xref: /openbmc/linux/tools/lib/bpf/btf.c (revision 4a3b33f8579af182ebcf9c7e9304effce505500e)
11bc38b8fSAlexei Starovoitov // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
28a138aedSMartin KaFai Lau /* Copyright (c) 2018 Facebook */
38a138aedSMartin KaFai Lau 
4cdb2f920SArnaldo Carvalho de Melo #include <endian.h>
596408c43SYonghong Song #include <stdio.h>
68a138aedSMartin KaFai Lau #include <stdlib.h>
78a138aedSMartin KaFai Lau #include <string.h>
8e6c64855SAndrii Nakryiko #include <fcntl.h>
98a138aedSMartin KaFai Lau #include <unistd.h>
108a138aedSMartin KaFai Lau #include <errno.h>
11fb2426adSMartin KaFai Lau #include <sys/utsname.h>
12fb2426adSMartin KaFai Lau #include <sys/param.h>
13fb2426adSMartin KaFai Lau #include <sys/stat.h>
14fb2426adSMartin KaFai Lau #include <linux/kernel.h>
158a138aedSMartin KaFai Lau #include <linux/err.h>
168a138aedSMartin KaFai Lau #include <linux/btf.h>
17e6c64855SAndrii Nakryiko #include <gelf.h>
188a138aedSMartin KaFai Lau #include "btf.h"
198a138aedSMartin KaFai Lau #include "bpf.h"
208461ef8bSYonghong Song #include "libbpf.h"
21d72386feSAndrii Nakryiko #include "libbpf_internal.h"
222fc3fc0bSAndrii Nakryiko #include "hashmap.h"
238a138aedSMartin KaFai Lau 
24fb2426adSMartin KaFai Lau #define BTF_MAX_NR_TYPES 0x7fffffffU
25fb2426adSMartin KaFai Lau #define BTF_MAX_STR_OFFSET 0x7fffffffU
268a138aedSMartin KaFai Lau 
278a138aedSMartin KaFai Lau static struct btf_type btf_void;
288a138aedSMartin KaFai Lau 
298a138aedSMartin KaFai Lau struct btf {
30b8604247SAndrii Nakryiko 	void *raw_data;
31b8604247SAndrii Nakryiko 	__u32 raw_size;
32b8604247SAndrii Nakryiko 
33b8604247SAndrii Nakryiko 	/*
34b8604247SAndrii Nakryiko 	 * When BTF is loaded from ELF or raw memory it is stored
35b8604247SAndrii Nakryiko 	 * in contiguous memory block, pointed to by raw_data pointer, and
36b8604247SAndrii Nakryiko 	 * hdr, types_data, and strs_data point inside that memory region to
37b8604247SAndrii Nakryiko 	 * respective parts of BTF representation:
38b8604247SAndrii Nakryiko 	 *
39b8604247SAndrii Nakryiko 	 * +--------------------------------+
40b8604247SAndrii Nakryiko 	 * |  Header  |  Types  |  Strings  |
41b8604247SAndrii Nakryiko 	 * +--------------------------------+
42b8604247SAndrii Nakryiko 	 * ^          ^         ^
43b8604247SAndrii Nakryiko 	 * |          |         |
44b8604247SAndrii Nakryiko 	 * hdr        |         |
45b8604247SAndrii Nakryiko 	 * types_data-+         |
46b8604247SAndrii Nakryiko 	 * strs_data------------+
47919d2b1dSAndrii Nakryiko 	 *
48919d2b1dSAndrii Nakryiko 	 * If BTF data is later modified, e.g., due to types added or
49919d2b1dSAndrii Nakryiko 	 * removed, BTF deduplication performed, etc, this contiguous
50919d2b1dSAndrii Nakryiko 	 * representation is broken up into three independently allocated
51919d2b1dSAndrii Nakryiko 	 * memory regions to be able to modify them independently.
52919d2b1dSAndrii Nakryiko 	 * raw_data is nulled out at that point, but can be later allocated
53919d2b1dSAndrii Nakryiko 	 * and cached again if user calls btf__get_raw_data(), at which point
54919d2b1dSAndrii Nakryiko 	 * raw_data will contain a contiguous copy of header, types, and
55919d2b1dSAndrii Nakryiko 	 * strings:
56919d2b1dSAndrii Nakryiko 	 *
57919d2b1dSAndrii Nakryiko 	 * +----------+  +---------+  +-----------+
58919d2b1dSAndrii Nakryiko 	 * |  Header  |  |  Types  |  |  Strings  |
59919d2b1dSAndrii Nakryiko 	 * +----------+  +---------+  +-----------+
60919d2b1dSAndrii Nakryiko 	 * ^             ^            ^
61919d2b1dSAndrii Nakryiko 	 * |             |            |
62919d2b1dSAndrii Nakryiko 	 * hdr           |            |
63919d2b1dSAndrii Nakryiko 	 * types_data----+            |
64919d2b1dSAndrii Nakryiko 	 * strs_data------------------+
65919d2b1dSAndrii Nakryiko 	 *
66919d2b1dSAndrii Nakryiko 	 *               +----------+---------+-----------+
67919d2b1dSAndrii Nakryiko 	 *               |  Header  |  Types  |  Strings  |
68919d2b1dSAndrii Nakryiko 	 * raw_data----->+----------+---------+-----------+
69b8604247SAndrii Nakryiko 	 */
708a138aedSMartin KaFai Lau 	struct btf_header *hdr;
71919d2b1dSAndrii Nakryiko 
72b8604247SAndrii Nakryiko 	void *types_data;
73919d2b1dSAndrii Nakryiko 	size_t types_data_cap; /* used size stored in hdr->type_len */
74b8604247SAndrii Nakryiko 
75b8604247SAndrii Nakryiko 	/* type ID to `struct btf_type *` lookup index */
76740e69c3SAndrii Nakryiko 	__u32 *type_offs;
77192f5a1fSAndrii Nakryiko 	size_t type_offs_cap;
785b891af7SMartin KaFai Lau 	__u32 nr_types;
79b8604247SAndrii Nakryiko 
80919d2b1dSAndrii Nakryiko 	void *strs_data;
81919d2b1dSAndrii Nakryiko 	size_t strs_data_cap; /* used size stored in hdr->str_len */
82919d2b1dSAndrii Nakryiko 
83919d2b1dSAndrii Nakryiko 	/* lookup index for each unique string in strings section */
84919d2b1dSAndrii Nakryiko 	struct hashmap *strs_hash;
85919d2b1dSAndrii Nakryiko 	/* whether strings are already deduplicated */
86919d2b1dSAndrii Nakryiko 	bool strs_deduped;
87b8604247SAndrii Nakryiko 	/* BTF object FD, if loaded into kernel */
888a138aedSMartin KaFai Lau 	int fd;
89b8604247SAndrii Nakryiko 
90b8604247SAndrii Nakryiko 	/* Pointer size (in bytes) for a target architecture of this BTF */
9144ad23dfSAndrii Nakryiko 	int ptr_sz;
928a138aedSMartin KaFai Lau };
938a138aedSMartin KaFai Lau 
94d7f5b5e0SYonghong Song static inline __u64 ptr_to_u64(const void *ptr)
95d7f5b5e0SYonghong Song {
96d7f5b5e0SYonghong Song 	return (__u64) (unsigned long) ptr;
97d7f5b5e0SYonghong Song }
98d7f5b5e0SYonghong Song 
99192f5a1fSAndrii Nakryiko /* Ensure given dynamically allocated memory region pointed to by *data* with
100192f5a1fSAndrii Nakryiko  * capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough
101192f5a1fSAndrii Nakryiko  * memory to accomodate *add_cnt* new elements, assuming *cur_cnt* elements
102192f5a1fSAndrii Nakryiko  * are already used. At most *max_cnt* elements can be ever allocated.
103192f5a1fSAndrii Nakryiko  * If necessary, memory is reallocated and all existing data is copied over,
104192f5a1fSAndrii Nakryiko  * new pointer to the memory region is stored at *data, new memory region
105192f5a1fSAndrii Nakryiko  * capacity (in number of elements) is stored in *cap.
106192f5a1fSAndrii Nakryiko  * On success, memory pointer to the beginning of unused memory is returned.
107192f5a1fSAndrii Nakryiko  * On error, NULL is returned.
108192f5a1fSAndrii Nakryiko  */
109192f5a1fSAndrii Nakryiko void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
110192f5a1fSAndrii Nakryiko 		  size_t cur_cnt, size_t max_cnt, size_t add_cnt)
1118a138aedSMartin KaFai Lau {
112192f5a1fSAndrii Nakryiko 	size_t new_cnt;
113192f5a1fSAndrii Nakryiko 	void *new_data;
1148a138aedSMartin KaFai Lau 
115192f5a1fSAndrii Nakryiko 	if (cur_cnt + add_cnt <= *cap_cnt)
116192f5a1fSAndrii Nakryiko 		return *data + cur_cnt * elem_sz;
1178a138aedSMartin KaFai Lau 
118192f5a1fSAndrii Nakryiko 	/* requested more than the set limit */
119192f5a1fSAndrii Nakryiko 	if (cur_cnt + add_cnt > max_cnt)
120192f5a1fSAndrii Nakryiko 		return NULL;
1218a138aedSMartin KaFai Lau 
122192f5a1fSAndrii Nakryiko 	new_cnt = *cap_cnt;
123192f5a1fSAndrii Nakryiko 	new_cnt += new_cnt / 4;		  /* expand by 25% */
124192f5a1fSAndrii Nakryiko 	if (new_cnt < 16)		  /* but at least 16 elements */
125192f5a1fSAndrii Nakryiko 		new_cnt = 16;
126192f5a1fSAndrii Nakryiko 	if (new_cnt > max_cnt)		  /* but not exceeding a set limit */
127192f5a1fSAndrii Nakryiko 		new_cnt = max_cnt;
128192f5a1fSAndrii Nakryiko 	if (new_cnt < cur_cnt + add_cnt)  /* also ensure we have enough memory */
129192f5a1fSAndrii Nakryiko 		new_cnt = cur_cnt + add_cnt;
1308a138aedSMartin KaFai Lau 
131192f5a1fSAndrii Nakryiko 	new_data = libbpf_reallocarray(*data, new_cnt, elem_sz);
132192f5a1fSAndrii Nakryiko 	if (!new_data)
133192f5a1fSAndrii Nakryiko 		return NULL;
1348a138aedSMartin KaFai Lau 
135192f5a1fSAndrii Nakryiko 	/* zero out newly allocated portion of memory */
136192f5a1fSAndrii Nakryiko 	memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz);
137192f5a1fSAndrii Nakryiko 
138192f5a1fSAndrii Nakryiko 	*data = new_data;
139192f5a1fSAndrii Nakryiko 	*cap_cnt = new_cnt;
140192f5a1fSAndrii Nakryiko 	return new_data + cur_cnt * elem_sz;
1418a138aedSMartin KaFai Lau }
1428a138aedSMartin KaFai Lau 
143192f5a1fSAndrii Nakryiko static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off)
144192f5a1fSAndrii Nakryiko {
145192f5a1fSAndrii Nakryiko 	__u32 *p;
1468a138aedSMartin KaFai Lau 
147192f5a1fSAndrii Nakryiko 	p = btf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32),
148192f5a1fSAndrii Nakryiko 			btf->nr_types + 1, BTF_MAX_NR_TYPES, 1);
149192f5a1fSAndrii Nakryiko 	if (!p)
150192f5a1fSAndrii Nakryiko 		return -ENOMEM;
151192f5a1fSAndrii Nakryiko 
152192f5a1fSAndrii Nakryiko 	*p = type_off;
1538a138aedSMartin KaFai Lau 	return 0;
1548a138aedSMartin KaFai Lau }
1558a138aedSMartin KaFai Lau 
1568461ef8bSYonghong Song static int btf_parse_hdr(struct btf *btf)
1578a138aedSMartin KaFai Lau {
1588a138aedSMartin KaFai Lau 	const struct btf_header *hdr = btf->hdr;
1595b891af7SMartin KaFai Lau 	__u32 meta_left;
1608a138aedSMartin KaFai Lau 
161b8604247SAndrii Nakryiko 	if (btf->raw_size < sizeof(struct btf_header)) {
1628461ef8bSYonghong Song 		pr_debug("BTF header not found\n");
1638a138aedSMartin KaFai Lau 		return -EINVAL;
1648a138aedSMartin KaFai Lau 	}
1658a138aedSMartin KaFai Lau 
1668a138aedSMartin KaFai Lau 	if (hdr->magic != BTF_MAGIC) {
1678461ef8bSYonghong Song 		pr_debug("Invalid BTF magic:%x\n", hdr->magic);
1688a138aedSMartin KaFai Lau 		return -EINVAL;
1698a138aedSMartin KaFai Lau 	}
1708a138aedSMartin KaFai Lau 
1718a138aedSMartin KaFai Lau 	if (hdr->version != BTF_VERSION) {
1728461ef8bSYonghong Song 		pr_debug("Unsupported BTF version:%u\n", hdr->version);
1738a138aedSMartin KaFai Lau 		return -ENOTSUP;
1748a138aedSMartin KaFai Lau 	}
1758a138aedSMartin KaFai Lau 
1768a138aedSMartin KaFai Lau 	if (hdr->flags) {
1778461ef8bSYonghong Song 		pr_debug("Unsupported BTF flags:%x\n", hdr->flags);
1788a138aedSMartin KaFai Lau 		return -ENOTSUP;
1798a138aedSMartin KaFai Lau 	}
1808a138aedSMartin KaFai Lau 
181b8604247SAndrii Nakryiko 	meta_left = btf->raw_size - sizeof(*hdr);
1828a138aedSMartin KaFai Lau 	if (!meta_left) {
1838461ef8bSYonghong Song 		pr_debug("BTF has no data\n");
1848a138aedSMartin KaFai Lau 		return -EINVAL;
1858a138aedSMartin KaFai Lau 	}
1868a138aedSMartin KaFai Lau 
1878a138aedSMartin KaFai Lau 	if (meta_left < hdr->type_off) {
1888461ef8bSYonghong Song 		pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off);
1898a138aedSMartin KaFai Lau 		return -EINVAL;
1908a138aedSMartin KaFai Lau 	}
1918a138aedSMartin KaFai Lau 
1928a138aedSMartin KaFai Lau 	if (meta_left < hdr->str_off) {
1938461ef8bSYonghong Song 		pr_debug("Invalid BTF string section offset:%u\n", hdr->str_off);
1948a138aedSMartin KaFai Lau 		return -EINVAL;
1958a138aedSMartin KaFai Lau 	}
1968a138aedSMartin KaFai Lau 
1978a138aedSMartin KaFai Lau 	if (hdr->type_off >= hdr->str_off) {
1988461ef8bSYonghong Song 		pr_debug("BTF type section offset >= string section offset. No type?\n");
1998a138aedSMartin KaFai Lau 		return -EINVAL;
2008a138aedSMartin KaFai Lau 	}
2018a138aedSMartin KaFai Lau 
2028a138aedSMartin KaFai Lau 	if (hdr->type_off & 0x02) {
2038461ef8bSYonghong Song 		pr_debug("BTF type section is not aligned to 4 bytes\n");
2048a138aedSMartin KaFai Lau 		return -EINVAL;
2058a138aedSMartin KaFai Lau 	}
2068a138aedSMartin KaFai Lau 
2078a138aedSMartin KaFai Lau 	return 0;
2088a138aedSMartin KaFai Lau }
2098a138aedSMartin KaFai Lau 
2108461ef8bSYonghong Song static int btf_parse_str_sec(struct btf *btf)
2118a138aedSMartin KaFai Lau {
2128a138aedSMartin KaFai Lau 	const struct btf_header *hdr = btf->hdr;
213b8604247SAndrii Nakryiko 	const char *start = btf->strs_data;
2148a138aedSMartin KaFai Lau 	const char *end = start + btf->hdr->str_len;
2158a138aedSMartin KaFai Lau 
2165aab392cSAndrii Nakryiko 	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET ||
2178a138aedSMartin KaFai Lau 	    start[0] || end[-1]) {
2188461ef8bSYonghong Song 		pr_debug("Invalid BTF string section\n");
2198a138aedSMartin KaFai Lau 		return -EINVAL;
2208a138aedSMartin KaFai Lau 	}
2218a138aedSMartin KaFai Lau 
2228a138aedSMartin KaFai Lau 	return 0;
2238a138aedSMartin KaFai Lau }
2248a138aedSMartin KaFai Lau 
225740e69c3SAndrii Nakryiko static int btf_type_size(const struct btf_type *t)
22669eaab04SAndrii Nakryiko {
22769eaab04SAndrii Nakryiko 	int base_size = sizeof(struct btf_type);
228b03bc685SAndrii Nakryiko 	__u16 vlen = btf_vlen(t);
22969eaab04SAndrii Nakryiko 
230b03bc685SAndrii Nakryiko 	switch (btf_kind(t)) {
23169eaab04SAndrii Nakryiko 	case BTF_KIND_FWD:
23269eaab04SAndrii Nakryiko 	case BTF_KIND_CONST:
23369eaab04SAndrii Nakryiko 	case BTF_KIND_VOLATILE:
23469eaab04SAndrii Nakryiko 	case BTF_KIND_RESTRICT:
23569eaab04SAndrii Nakryiko 	case BTF_KIND_PTR:
23669eaab04SAndrii Nakryiko 	case BTF_KIND_TYPEDEF:
23769eaab04SAndrii Nakryiko 	case BTF_KIND_FUNC:
23869eaab04SAndrii Nakryiko 		return base_size;
23969eaab04SAndrii Nakryiko 	case BTF_KIND_INT:
24069eaab04SAndrii Nakryiko 		return base_size + sizeof(__u32);
24169eaab04SAndrii Nakryiko 	case BTF_KIND_ENUM:
24269eaab04SAndrii Nakryiko 		return base_size + vlen * sizeof(struct btf_enum);
24369eaab04SAndrii Nakryiko 	case BTF_KIND_ARRAY:
24469eaab04SAndrii Nakryiko 		return base_size + sizeof(struct btf_array);
24569eaab04SAndrii Nakryiko 	case BTF_KIND_STRUCT:
24669eaab04SAndrii Nakryiko 	case BTF_KIND_UNION:
24769eaab04SAndrii Nakryiko 		return base_size + vlen * sizeof(struct btf_member);
24869eaab04SAndrii Nakryiko 	case BTF_KIND_FUNC_PROTO:
24969eaab04SAndrii Nakryiko 		return base_size + vlen * sizeof(struct btf_param);
2501713d68bSDaniel Borkmann 	case BTF_KIND_VAR:
2511713d68bSDaniel Borkmann 		return base_size + sizeof(struct btf_var);
2521713d68bSDaniel Borkmann 	case BTF_KIND_DATASEC:
2531713d68bSDaniel Borkmann 		return base_size + vlen * sizeof(struct btf_var_secinfo);
25469eaab04SAndrii Nakryiko 	default:
255b03bc685SAndrii Nakryiko 		pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
25669eaab04SAndrii Nakryiko 		return -EINVAL;
25769eaab04SAndrii Nakryiko 	}
25869eaab04SAndrii Nakryiko }
25969eaab04SAndrii Nakryiko 
2608461ef8bSYonghong Song static int btf_parse_type_sec(struct btf *btf)
2618a138aedSMartin KaFai Lau {
2628a138aedSMartin KaFai Lau 	struct btf_header *hdr = btf->hdr;
263b8604247SAndrii Nakryiko 	void *next_type = btf->types_data;
264740e69c3SAndrii Nakryiko 	void *end_type = next_type + hdr->type_len;
265192f5a1fSAndrii Nakryiko 	int err, type_size;
266192f5a1fSAndrii Nakryiko 
267192f5a1fSAndrii Nakryiko 	/* VOID (type_id == 0) is specially handled by btf__get_type_by_id(),
268192f5a1fSAndrii Nakryiko 	 * so ensure we can never properly use its offset from index by
269192f5a1fSAndrii Nakryiko 	 * setting it to a large value
270192f5a1fSAndrii Nakryiko 	 */
271192f5a1fSAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, UINT_MAX);
272192f5a1fSAndrii Nakryiko 	if (err)
273192f5a1fSAndrii Nakryiko 		return err;
274740e69c3SAndrii Nakryiko 
2758a138aedSMartin KaFai Lau 	while (next_type < end_type) {
276740e69c3SAndrii Nakryiko 		err = btf_add_type_idx_entry(btf, next_type - btf->types_data);
2778a138aedSMartin KaFai Lau 		if (err)
2788a138aedSMartin KaFai Lau 			return err;
279740e69c3SAndrii Nakryiko 
280740e69c3SAndrii Nakryiko 		type_size = btf_type_size(next_type);
281740e69c3SAndrii Nakryiko 		if (type_size < 0)
282740e69c3SAndrii Nakryiko 			return type_size;
283740e69c3SAndrii Nakryiko 
284740e69c3SAndrii Nakryiko 		next_type += type_size;
285740e69c3SAndrii Nakryiko 		btf->nr_types++;
2868a138aedSMartin KaFai Lau 	}
2878a138aedSMartin KaFai Lau 
2888a138aedSMartin KaFai Lau 	return 0;
2898a138aedSMartin KaFai Lau }
2908a138aedSMartin KaFai Lau 
2919c651127SAndrii Nakryiko __u32 btf__get_nr_types(const struct btf *btf)
2929c651127SAndrii Nakryiko {
2939c651127SAndrii Nakryiko 	return btf->nr_types;
2949c651127SAndrii Nakryiko }
2959c651127SAndrii Nakryiko 
296740e69c3SAndrii Nakryiko /* internal helper returning non-const pointer to a type */
297740e69c3SAndrii Nakryiko static struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id)
298740e69c3SAndrii Nakryiko {
299740e69c3SAndrii Nakryiko 	if (type_id == 0)
300740e69c3SAndrii Nakryiko 		return &btf_void;
301740e69c3SAndrii Nakryiko 
302740e69c3SAndrii Nakryiko 	return btf->types_data + btf->type_offs[type_id];
303740e69c3SAndrii Nakryiko }
304740e69c3SAndrii Nakryiko 
30538d5d3b3SMartin KaFai Lau const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
3068a138aedSMartin KaFai Lau {
3078a138aedSMartin KaFai Lau 	if (type_id > btf->nr_types)
3088a138aedSMartin KaFai Lau 		return NULL;
309740e69c3SAndrii Nakryiko 	return btf_type_by_id((struct btf *)btf, type_id);
3108a138aedSMartin KaFai Lau }
3118a138aedSMartin KaFai Lau 
31244ad23dfSAndrii Nakryiko static int determine_ptr_size(const struct btf *btf)
31344ad23dfSAndrii Nakryiko {
31444ad23dfSAndrii Nakryiko 	const struct btf_type *t;
31544ad23dfSAndrii Nakryiko 	const char *name;
31644ad23dfSAndrii Nakryiko 	int i;
31744ad23dfSAndrii Nakryiko 
31844ad23dfSAndrii Nakryiko 	for (i = 1; i <= btf->nr_types; i++) {
31944ad23dfSAndrii Nakryiko 		t = btf__type_by_id(btf, i);
32044ad23dfSAndrii Nakryiko 		if (!btf_is_int(t))
32144ad23dfSAndrii Nakryiko 			continue;
32244ad23dfSAndrii Nakryiko 
32344ad23dfSAndrii Nakryiko 		name = btf__name_by_offset(btf, t->name_off);
32444ad23dfSAndrii Nakryiko 		if (!name)
32544ad23dfSAndrii Nakryiko 			continue;
32644ad23dfSAndrii Nakryiko 
32744ad23dfSAndrii Nakryiko 		if (strcmp(name, "long int") == 0 ||
32844ad23dfSAndrii Nakryiko 		    strcmp(name, "long unsigned int") == 0) {
32944ad23dfSAndrii Nakryiko 			if (t->size != 4 && t->size != 8)
33044ad23dfSAndrii Nakryiko 				continue;
33144ad23dfSAndrii Nakryiko 			return t->size;
33244ad23dfSAndrii Nakryiko 		}
33344ad23dfSAndrii Nakryiko 	}
33444ad23dfSAndrii Nakryiko 
33544ad23dfSAndrii Nakryiko 	return -1;
33644ad23dfSAndrii Nakryiko }
33744ad23dfSAndrii Nakryiko 
33844ad23dfSAndrii Nakryiko static size_t btf_ptr_sz(const struct btf *btf)
33944ad23dfSAndrii Nakryiko {
34044ad23dfSAndrii Nakryiko 	if (!btf->ptr_sz)
34144ad23dfSAndrii Nakryiko 		((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
34244ad23dfSAndrii Nakryiko 	return btf->ptr_sz < 0 ? sizeof(void *) : btf->ptr_sz;
34344ad23dfSAndrii Nakryiko }
34444ad23dfSAndrii Nakryiko 
34544ad23dfSAndrii Nakryiko /* Return pointer size this BTF instance assumes. The size is heuristically
34644ad23dfSAndrii Nakryiko  * determined by looking for 'long' or 'unsigned long' integer type and
34744ad23dfSAndrii Nakryiko  * recording its size in bytes. If BTF type information doesn't have any such
34844ad23dfSAndrii Nakryiko  * type, this function returns 0. In the latter case, native architecture's
34944ad23dfSAndrii Nakryiko  * pointer size is assumed, so will be either 4 or 8, depending on
35044ad23dfSAndrii Nakryiko  * architecture that libbpf was compiled for. It's possible to override
35144ad23dfSAndrii Nakryiko  * guessed value by using btf__set_pointer_size() API.
35244ad23dfSAndrii Nakryiko  */
35344ad23dfSAndrii Nakryiko size_t btf__pointer_size(const struct btf *btf)
35444ad23dfSAndrii Nakryiko {
35544ad23dfSAndrii Nakryiko 	if (!btf->ptr_sz)
35644ad23dfSAndrii Nakryiko 		((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
35744ad23dfSAndrii Nakryiko 
35844ad23dfSAndrii Nakryiko 	if (btf->ptr_sz < 0)
35944ad23dfSAndrii Nakryiko 		/* not enough BTF type info to guess */
36044ad23dfSAndrii Nakryiko 		return 0;
36144ad23dfSAndrii Nakryiko 
36244ad23dfSAndrii Nakryiko 	return btf->ptr_sz;
36344ad23dfSAndrii Nakryiko }
36444ad23dfSAndrii Nakryiko 
36544ad23dfSAndrii Nakryiko /* Override or set pointer size in bytes. Only values of 4 and 8 are
36644ad23dfSAndrii Nakryiko  * supported.
36744ad23dfSAndrii Nakryiko  */
36844ad23dfSAndrii Nakryiko int btf__set_pointer_size(struct btf *btf, size_t ptr_sz)
36944ad23dfSAndrii Nakryiko {
37044ad23dfSAndrii Nakryiko 	if (ptr_sz != 4 && ptr_sz != 8)
37144ad23dfSAndrii Nakryiko 		return -EINVAL;
37244ad23dfSAndrii Nakryiko 	btf->ptr_sz = ptr_sz;
37344ad23dfSAndrii Nakryiko 	return 0;
37444ad23dfSAndrii Nakryiko }
37544ad23dfSAndrii Nakryiko 
3768a138aedSMartin KaFai Lau static bool btf_type_is_void(const struct btf_type *t)
3778a138aedSMartin KaFai Lau {
378b03bc685SAndrii Nakryiko 	return t == &btf_void || btf_is_fwd(t);
3798a138aedSMartin KaFai Lau }
3808a138aedSMartin KaFai Lau 
3818a138aedSMartin KaFai Lau static bool btf_type_is_void_or_null(const struct btf_type *t)
3828a138aedSMartin KaFai Lau {
3838a138aedSMartin KaFai Lau 	return !t || btf_type_is_void(t);
3848a138aedSMartin KaFai Lau }
3858a138aedSMartin KaFai Lau 
3868a138aedSMartin KaFai Lau #define MAX_RESOLVE_DEPTH 32
3878a138aedSMartin KaFai Lau 
3885b891af7SMartin KaFai Lau __s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
3898a138aedSMartin KaFai Lau {
3908a138aedSMartin KaFai Lau 	const struct btf_array *array;
3918a138aedSMartin KaFai Lau 	const struct btf_type *t;
3925b891af7SMartin KaFai Lau 	__u32 nelems = 1;
3935b891af7SMartin KaFai Lau 	__s64 size = -1;
3948a138aedSMartin KaFai Lau 	int i;
3958a138aedSMartin KaFai Lau 
39692b57121SOkash Khawaja 	t = btf__type_by_id(btf, type_id);
3978a138aedSMartin KaFai Lau 	for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
3988a138aedSMartin KaFai Lau 	     i++) {
399b03bc685SAndrii Nakryiko 		switch (btf_kind(t)) {
40069eaab04SAndrii Nakryiko 		case BTF_KIND_INT:
40169eaab04SAndrii Nakryiko 		case BTF_KIND_STRUCT:
40269eaab04SAndrii Nakryiko 		case BTF_KIND_UNION:
40369eaab04SAndrii Nakryiko 		case BTF_KIND_ENUM:
4041713d68bSDaniel Borkmann 		case BTF_KIND_DATASEC:
40569eaab04SAndrii Nakryiko 			size = t->size;
40669eaab04SAndrii Nakryiko 			goto done;
40769eaab04SAndrii Nakryiko 		case BTF_KIND_PTR:
40844ad23dfSAndrii Nakryiko 			size = btf_ptr_sz(btf);
40969eaab04SAndrii Nakryiko 			goto done;
4108a138aedSMartin KaFai Lau 		case BTF_KIND_TYPEDEF:
4118a138aedSMartin KaFai Lau 		case BTF_KIND_VOLATILE:
4128a138aedSMartin KaFai Lau 		case BTF_KIND_CONST:
4138a138aedSMartin KaFai Lau 		case BTF_KIND_RESTRICT:
4141713d68bSDaniel Borkmann 		case BTF_KIND_VAR:
4158a138aedSMartin KaFai Lau 			type_id = t->type;
4168a138aedSMartin KaFai Lau 			break;
4178a138aedSMartin KaFai Lau 		case BTF_KIND_ARRAY:
418b03bc685SAndrii Nakryiko 			array = btf_array(t);
4198a138aedSMartin KaFai Lau 			if (nelems && array->nelems > UINT32_MAX / nelems)
4208a138aedSMartin KaFai Lau 				return -E2BIG;
4218a138aedSMartin KaFai Lau 			nelems *= array->nelems;
4228a138aedSMartin KaFai Lau 			type_id = array->type;
4238a138aedSMartin KaFai Lau 			break;
4248a138aedSMartin KaFai Lau 		default:
4258a138aedSMartin KaFai Lau 			return -EINVAL;
4268a138aedSMartin KaFai Lau 		}
4278a138aedSMartin KaFai Lau 
42892b57121SOkash Khawaja 		t = btf__type_by_id(btf, type_id);
4298a138aedSMartin KaFai Lau 	}
4308a138aedSMartin KaFai Lau 
431994021a7SAndrii Nakryiko done:
4328a138aedSMartin KaFai Lau 	if (size < 0)
4338a138aedSMartin KaFai Lau 		return -EINVAL;
4348a138aedSMartin KaFai Lau 	if (nelems && size > UINT32_MAX / nelems)
4358a138aedSMartin KaFai Lau 		return -E2BIG;
4368a138aedSMartin KaFai Lau 
4378a138aedSMartin KaFai Lau 	return nelems * size;
4388a138aedSMartin KaFai Lau }
4398a138aedSMartin KaFai Lau 
4403d208f4cSAndrii Nakryiko int btf__align_of(const struct btf *btf, __u32 id)
4413d208f4cSAndrii Nakryiko {
4423d208f4cSAndrii Nakryiko 	const struct btf_type *t = btf__type_by_id(btf, id);
4433d208f4cSAndrii Nakryiko 	__u16 kind = btf_kind(t);
4443d208f4cSAndrii Nakryiko 
4453d208f4cSAndrii Nakryiko 	switch (kind) {
4463d208f4cSAndrii Nakryiko 	case BTF_KIND_INT:
4473d208f4cSAndrii Nakryiko 	case BTF_KIND_ENUM:
44844ad23dfSAndrii Nakryiko 		return min(btf_ptr_sz(btf), (size_t)t->size);
4493d208f4cSAndrii Nakryiko 	case BTF_KIND_PTR:
45044ad23dfSAndrii Nakryiko 		return btf_ptr_sz(btf);
4513d208f4cSAndrii Nakryiko 	case BTF_KIND_TYPEDEF:
4523d208f4cSAndrii Nakryiko 	case BTF_KIND_VOLATILE:
4533d208f4cSAndrii Nakryiko 	case BTF_KIND_CONST:
4543d208f4cSAndrii Nakryiko 	case BTF_KIND_RESTRICT:
4553d208f4cSAndrii Nakryiko 		return btf__align_of(btf, t->type);
4563d208f4cSAndrii Nakryiko 	case BTF_KIND_ARRAY:
4573d208f4cSAndrii Nakryiko 		return btf__align_of(btf, btf_array(t)->type);
4583d208f4cSAndrii Nakryiko 	case BTF_KIND_STRUCT:
4593d208f4cSAndrii Nakryiko 	case BTF_KIND_UNION: {
4603d208f4cSAndrii Nakryiko 		const struct btf_member *m = btf_members(t);
4613d208f4cSAndrii Nakryiko 		__u16 vlen = btf_vlen(t);
462a79ac2d1SPrashant Bhole 		int i, max_align = 1, align;
4633d208f4cSAndrii Nakryiko 
4643d208f4cSAndrii Nakryiko 		for (i = 0; i < vlen; i++, m++) {
465a79ac2d1SPrashant Bhole 			align = btf__align_of(btf, m->type);
466a79ac2d1SPrashant Bhole 			if (align <= 0)
467a79ac2d1SPrashant Bhole 				return align;
468a79ac2d1SPrashant Bhole 			max_align = max(max_align, align);
4693d208f4cSAndrii Nakryiko 		}
4703d208f4cSAndrii Nakryiko 
471a79ac2d1SPrashant Bhole 		return max_align;
4723d208f4cSAndrii Nakryiko 	}
4733d208f4cSAndrii Nakryiko 	default:
4743d208f4cSAndrii Nakryiko 		pr_warn("unsupported BTF_KIND:%u\n", btf_kind(t));
4753d208f4cSAndrii Nakryiko 		return 0;
4763d208f4cSAndrii Nakryiko 	}
4773d208f4cSAndrii Nakryiko }
4783d208f4cSAndrii Nakryiko 
47992b57121SOkash Khawaja int btf__resolve_type(const struct btf *btf, __u32 type_id)
48092b57121SOkash Khawaja {
48192b57121SOkash Khawaja 	const struct btf_type *t;
48292b57121SOkash Khawaja 	int depth = 0;
48392b57121SOkash Khawaja 
48492b57121SOkash Khawaja 	t = btf__type_by_id(btf, type_id);
48592b57121SOkash Khawaja 	while (depth < MAX_RESOLVE_DEPTH &&
48692b57121SOkash Khawaja 	       !btf_type_is_void_or_null(t) &&
487b03bc685SAndrii Nakryiko 	       (btf_is_mod(t) || btf_is_typedef(t) || btf_is_var(t))) {
48892b57121SOkash Khawaja 		type_id = t->type;
48992b57121SOkash Khawaja 		t = btf__type_by_id(btf, type_id);
49092b57121SOkash Khawaja 		depth++;
49192b57121SOkash Khawaja 	}
49292b57121SOkash Khawaja 
49392b57121SOkash Khawaja 	if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
49492b57121SOkash Khawaja 		return -EINVAL;
49592b57121SOkash Khawaja 
49692b57121SOkash Khawaja 	return type_id;
49792b57121SOkash Khawaja }
49892b57121SOkash Khawaja 
4995b891af7SMartin KaFai Lau __s32 btf__find_by_name(const struct btf *btf, const char *type_name)
5008a138aedSMartin KaFai Lau {
5015b891af7SMartin KaFai Lau 	__u32 i;
5028a138aedSMartin KaFai Lau 
5038a138aedSMartin KaFai Lau 	if (!strcmp(type_name, "void"))
5048a138aedSMartin KaFai Lau 		return 0;
5058a138aedSMartin KaFai Lau 
5068a138aedSMartin KaFai Lau 	for (i = 1; i <= btf->nr_types; i++) {
507740e69c3SAndrii Nakryiko 		const struct btf_type *t = btf__type_by_id(btf, i);
50892b57121SOkash Khawaja 		const char *name = btf__name_by_offset(btf, t->name_off);
5098a138aedSMartin KaFai Lau 
5108a138aedSMartin KaFai Lau 		if (name && !strcmp(type_name, name))
5118a138aedSMartin KaFai Lau 			return i;
5128a138aedSMartin KaFai Lau 	}
5138a138aedSMartin KaFai Lau 
5148a138aedSMartin KaFai Lau 	return -ENOENT;
5158a138aedSMartin KaFai Lau }
5168a138aedSMartin KaFai Lau 
5171442e287SAlexei Starovoitov __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
5181442e287SAlexei Starovoitov 			     __u32 kind)
5191442e287SAlexei Starovoitov {
5201442e287SAlexei Starovoitov 	__u32 i;
5211442e287SAlexei Starovoitov 
5221442e287SAlexei Starovoitov 	if (kind == BTF_KIND_UNKN || !strcmp(type_name, "void"))
5231442e287SAlexei Starovoitov 		return 0;
5241442e287SAlexei Starovoitov 
5251442e287SAlexei Starovoitov 	for (i = 1; i <= btf->nr_types; i++) {
526740e69c3SAndrii Nakryiko 		const struct btf_type *t = btf__type_by_id(btf, i);
5271442e287SAlexei Starovoitov 		const char *name;
5281442e287SAlexei Starovoitov 
5291442e287SAlexei Starovoitov 		if (btf_kind(t) != kind)
5301442e287SAlexei Starovoitov 			continue;
5311442e287SAlexei Starovoitov 		name = btf__name_by_offset(btf, t->name_off);
5321442e287SAlexei Starovoitov 		if (name && !strcmp(type_name, name))
5331442e287SAlexei Starovoitov 			return i;
5341442e287SAlexei Starovoitov 	}
5351442e287SAlexei Starovoitov 
5361442e287SAlexei Starovoitov 	return -ENOENT;
5371442e287SAlexei Starovoitov }
5381442e287SAlexei Starovoitov 
539919d2b1dSAndrii Nakryiko static bool btf_is_modifiable(const struct btf *btf)
540919d2b1dSAndrii Nakryiko {
541919d2b1dSAndrii Nakryiko 	return (void *)btf->hdr != btf->raw_data;
542919d2b1dSAndrii Nakryiko }
543919d2b1dSAndrii Nakryiko 
5448a138aedSMartin KaFai Lau void btf__free(struct btf *btf)
5458a138aedSMartin KaFai Lau {
54650450fc7SAndrii Nakryiko 	if (IS_ERR_OR_NULL(btf))
5478a138aedSMartin KaFai Lau 		return;
5488a138aedSMartin KaFai Lau 
54981372e12SAndrii Nakryiko 	if (btf->fd >= 0)
5508a138aedSMartin KaFai Lau 		close(btf->fd);
5518a138aedSMartin KaFai Lau 
552919d2b1dSAndrii Nakryiko 	if (btf_is_modifiable(btf)) {
553919d2b1dSAndrii Nakryiko 		/* if BTF was modified after loading, it will have a split
554919d2b1dSAndrii Nakryiko 		 * in-memory representation for header, types, and strings
555919d2b1dSAndrii Nakryiko 		 * sections, so we need to free all of them individually. It
556919d2b1dSAndrii Nakryiko 		 * might still have a cached contiguous raw data present,
557919d2b1dSAndrii Nakryiko 		 * which will be unconditionally freed below.
558919d2b1dSAndrii Nakryiko 		 */
559919d2b1dSAndrii Nakryiko 		free(btf->hdr);
560919d2b1dSAndrii Nakryiko 		free(btf->types_data);
561919d2b1dSAndrii Nakryiko 		free(btf->strs_data);
562919d2b1dSAndrii Nakryiko 	}
563b8604247SAndrii Nakryiko 	free(btf->raw_data);
564740e69c3SAndrii Nakryiko 	free(btf->type_offs);
5658a138aedSMartin KaFai Lau 	free(btf);
5668a138aedSMartin KaFai Lau }
5678a138aedSMartin KaFai Lau 
568a871b043SAndrii Nakryiko struct btf *btf__new_empty(void)
569a871b043SAndrii Nakryiko {
570a871b043SAndrii Nakryiko 	struct btf *btf;
571a871b043SAndrii Nakryiko 
572a871b043SAndrii Nakryiko 	btf = calloc(1, sizeof(*btf));
573a871b043SAndrii Nakryiko 	if (!btf)
574a871b043SAndrii Nakryiko 		return ERR_PTR(-ENOMEM);
575a871b043SAndrii Nakryiko 	btf->fd = -1;
576a871b043SAndrii Nakryiko 	btf->ptr_sz = sizeof(void *);
577a871b043SAndrii Nakryiko 
578a871b043SAndrii Nakryiko 	/* +1 for empty string at offset 0 */
579a871b043SAndrii Nakryiko 	btf->raw_size = sizeof(struct btf_header) + 1;
580a871b043SAndrii Nakryiko 	btf->raw_data = calloc(1, btf->raw_size);
581a871b043SAndrii Nakryiko 	if (!btf->raw_data) {
582a871b043SAndrii Nakryiko 		free(btf);
583a871b043SAndrii Nakryiko 		return ERR_PTR(-ENOMEM);
584a871b043SAndrii Nakryiko 	}
585a871b043SAndrii Nakryiko 
586a871b043SAndrii Nakryiko 	btf->hdr = btf->raw_data;
587a871b043SAndrii Nakryiko 	btf->hdr->hdr_len = sizeof(struct btf_header);
588a871b043SAndrii Nakryiko 	btf->hdr->magic = BTF_MAGIC;
589a871b043SAndrii Nakryiko 	btf->hdr->version = BTF_VERSION;
590a871b043SAndrii Nakryiko 
591a871b043SAndrii Nakryiko 	btf->types_data = btf->raw_data + btf->hdr->hdr_len;
592a871b043SAndrii Nakryiko 	btf->strs_data = btf->raw_data + btf->hdr->hdr_len;
593a871b043SAndrii Nakryiko 	btf->hdr->str_len = 1; /* empty string at offset 0 */
594a871b043SAndrii Nakryiko 
595a871b043SAndrii Nakryiko 	return btf;
596a871b043SAndrii Nakryiko }
597a871b043SAndrii Nakryiko 
5985c3320d7SAndrii Nakryiko struct btf *btf__new(const void *data, __u32 size)
5998a138aedSMartin KaFai Lau {
6008a138aedSMartin KaFai Lau 	struct btf *btf;
6018a138aedSMartin KaFai Lau 	int err;
6028a138aedSMartin KaFai Lau 
6038a138aedSMartin KaFai Lau 	btf = calloc(1, sizeof(struct btf));
6048a138aedSMartin KaFai Lau 	if (!btf)
6058a138aedSMartin KaFai Lau 		return ERR_PTR(-ENOMEM);
6068a138aedSMartin KaFai Lau 
6078a138aedSMartin KaFai Lau 	btf->fd = -1;
6088a138aedSMartin KaFai Lau 
609b8604247SAndrii Nakryiko 	btf->raw_data = malloc(size);
610b8604247SAndrii Nakryiko 	if (!btf->raw_data) {
6118a138aedSMartin KaFai Lau 		err = -ENOMEM;
6128a138aedSMartin KaFai Lau 		goto done;
6138a138aedSMartin KaFai Lau 	}
614b8604247SAndrii Nakryiko 	memcpy(btf->raw_data, data, size);
615b8604247SAndrii Nakryiko 	btf->raw_size = size;
6168a138aedSMartin KaFai Lau 
617b8604247SAndrii Nakryiko 	btf->hdr = btf->raw_data;
6188461ef8bSYonghong Song 	err = btf_parse_hdr(btf);
6198a138aedSMartin KaFai Lau 	if (err)
6208a138aedSMartin KaFai Lau 		goto done;
6218a138aedSMartin KaFai Lau 
622b8604247SAndrii Nakryiko 	btf->strs_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->str_off;
623b8604247SAndrii Nakryiko 	btf->types_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->type_off;
6248a138aedSMartin KaFai Lau 
625b8604247SAndrii Nakryiko 	err = btf_parse_str_sec(btf);
626b8604247SAndrii Nakryiko 	err = err ?: btf_parse_type_sec(btf);
6278a138aedSMartin KaFai Lau 
6288a138aedSMartin KaFai Lau done:
6298a138aedSMartin KaFai Lau 	if (err) {
6308a138aedSMartin KaFai Lau 		btf__free(btf);
6318a138aedSMartin KaFai Lau 		return ERR_PTR(err);
6328a138aedSMartin KaFai Lau 	}
6338a138aedSMartin KaFai Lau 
6348a138aedSMartin KaFai Lau 	return btf;
6358a138aedSMartin KaFai Lau }
6368a138aedSMartin KaFai Lau 
637e6c64855SAndrii Nakryiko static bool btf_check_endianness(const GElf_Ehdr *ehdr)
638e6c64855SAndrii Nakryiko {
639cdb2f920SArnaldo Carvalho de Melo #if __BYTE_ORDER == __LITTLE_ENDIAN
640e6c64855SAndrii Nakryiko 	return ehdr->e_ident[EI_DATA] == ELFDATA2LSB;
641cdb2f920SArnaldo Carvalho de Melo #elif __BYTE_ORDER == __BIG_ENDIAN
642e6c64855SAndrii Nakryiko 	return ehdr->e_ident[EI_DATA] == ELFDATA2MSB;
643e6c64855SAndrii Nakryiko #else
644e6c64855SAndrii Nakryiko # error "Unrecognized __BYTE_ORDER__"
645e6c64855SAndrii Nakryiko #endif
646e6c64855SAndrii Nakryiko }
647e6c64855SAndrii Nakryiko 
648e6c64855SAndrii Nakryiko struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext)
649e6c64855SAndrii Nakryiko {
650e6c64855SAndrii Nakryiko 	Elf_Data *btf_data = NULL, *btf_ext_data = NULL;
651e6c64855SAndrii Nakryiko 	int err = 0, fd = -1, idx = 0;
652e6c64855SAndrii Nakryiko 	struct btf *btf = NULL;
653e6c64855SAndrii Nakryiko 	Elf_Scn *scn = NULL;
654e6c64855SAndrii Nakryiko 	Elf *elf = NULL;
655e6c64855SAndrii Nakryiko 	GElf_Ehdr ehdr;
656e6c64855SAndrii Nakryiko 
657e6c64855SAndrii Nakryiko 	if (elf_version(EV_CURRENT) == EV_NONE) {
658be18010eSKefeng Wang 		pr_warn("failed to init libelf for %s\n", path);
659e6c64855SAndrii Nakryiko 		return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
660e6c64855SAndrii Nakryiko 	}
661e6c64855SAndrii Nakryiko 
662e6c64855SAndrii Nakryiko 	fd = open(path, O_RDONLY);
663e6c64855SAndrii Nakryiko 	if (fd < 0) {
664e6c64855SAndrii Nakryiko 		err = -errno;
665be18010eSKefeng Wang 		pr_warn("failed to open %s: %s\n", path, strerror(errno));
666e6c64855SAndrii Nakryiko 		return ERR_PTR(err);
667e6c64855SAndrii Nakryiko 	}
668e6c64855SAndrii Nakryiko 
669e6c64855SAndrii Nakryiko 	err = -LIBBPF_ERRNO__FORMAT;
670e6c64855SAndrii Nakryiko 
671e6c64855SAndrii Nakryiko 	elf = elf_begin(fd, ELF_C_READ, NULL);
672e6c64855SAndrii Nakryiko 	if (!elf) {
673be18010eSKefeng Wang 		pr_warn("failed to open %s as ELF file\n", path);
674e6c64855SAndrii Nakryiko 		goto done;
675e6c64855SAndrii Nakryiko 	}
676e6c64855SAndrii Nakryiko 	if (!gelf_getehdr(elf, &ehdr)) {
677be18010eSKefeng Wang 		pr_warn("failed to get EHDR from %s\n", path);
678e6c64855SAndrii Nakryiko 		goto done;
679e6c64855SAndrii Nakryiko 	}
680e6c64855SAndrii Nakryiko 	if (!btf_check_endianness(&ehdr)) {
681be18010eSKefeng Wang 		pr_warn("non-native ELF endianness is not supported\n");
682e6c64855SAndrii Nakryiko 		goto done;
683e6c64855SAndrii Nakryiko 	}
684e6c64855SAndrii Nakryiko 	if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) {
685be18010eSKefeng Wang 		pr_warn("failed to get e_shstrndx from %s\n", path);
686e6c64855SAndrii Nakryiko 		goto done;
687e6c64855SAndrii Nakryiko 	}
688e6c64855SAndrii Nakryiko 
689e6c64855SAndrii Nakryiko 	while ((scn = elf_nextscn(elf, scn)) != NULL) {
690e6c64855SAndrii Nakryiko 		GElf_Shdr sh;
691e6c64855SAndrii Nakryiko 		char *name;
692e6c64855SAndrii Nakryiko 
693e6c64855SAndrii Nakryiko 		idx++;
694e6c64855SAndrii Nakryiko 		if (gelf_getshdr(scn, &sh) != &sh) {
695be18010eSKefeng Wang 			pr_warn("failed to get section(%d) header from %s\n",
696e6c64855SAndrii Nakryiko 				idx, path);
697e6c64855SAndrii Nakryiko 			goto done;
698e6c64855SAndrii Nakryiko 		}
699e6c64855SAndrii Nakryiko 		name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name);
700e6c64855SAndrii Nakryiko 		if (!name) {
701be18010eSKefeng Wang 			pr_warn("failed to get section(%d) name from %s\n",
702e6c64855SAndrii Nakryiko 				idx, path);
703e6c64855SAndrii Nakryiko 			goto done;
704e6c64855SAndrii Nakryiko 		}
705e6c64855SAndrii Nakryiko 		if (strcmp(name, BTF_ELF_SEC) == 0) {
706e6c64855SAndrii Nakryiko 			btf_data = elf_getdata(scn, 0);
707e6c64855SAndrii Nakryiko 			if (!btf_data) {
708be18010eSKefeng Wang 				pr_warn("failed to get section(%d, %s) data from %s\n",
709e6c64855SAndrii Nakryiko 					idx, name, path);
710e6c64855SAndrii Nakryiko 				goto done;
711e6c64855SAndrii Nakryiko 			}
712e6c64855SAndrii Nakryiko 			continue;
713e6c64855SAndrii Nakryiko 		} else if (btf_ext && strcmp(name, BTF_EXT_ELF_SEC) == 0) {
714e6c64855SAndrii Nakryiko 			btf_ext_data = elf_getdata(scn, 0);
715e6c64855SAndrii Nakryiko 			if (!btf_ext_data) {
716be18010eSKefeng Wang 				pr_warn("failed to get section(%d, %s) data from %s\n",
717e6c64855SAndrii Nakryiko 					idx, name, path);
718e6c64855SAndrii Nakryiko 				goto done;
719e6c64855SAndrii Nakryiko 			}
720e6c64855SAndrii Nakryiko 			continue;
721e6c64855SAndrii Nakryiko 		}
722e6c64855SAndrii Nakryiko 	}
723e6c64855SAndrii Nakryiko 
724e6c64855SAndrii Nakryiko 	err = 0;
725e6c64855SAndrii Nakryiko 
726e6c64855SAndrii Nakryiko 	if (!btf_data) {
727e6c64855SAndrii Nakryiko 		err = -ENOENT;
728e6c64855SAndrii Nakryiko 		goto done;
729e6c64855SAndrii Nakryiko 	}
730e6c64855SAndrii Nakryiko 	btf = btf__new(btf_data->d_buf, btf_data->d_size);
731e6c64855SAndrii Nakryiko 	if (IS_ERR(btf))
732e6c64855SAndrii Nakryiko 		goto done;
733e6c64855SAndrii Nakryiko 
73444ad23dfSAndrii Nakryiko 	switch (gelf_getclass(elf)) {
73544ad23dfSAndrii Nakryiko 	case ELFCLASS32:
73644ad23dfSAndrii Nakryiko 		btf__set_pointer_size(btf, 4);
73744ad23dfSAndrii Nakryiko 		break;
73844ad23dfSAndrii Nakryiko 	case ELFCLASS64:
73944ad23dfSAndrii Nakryiko 		btf__set_pointer_size(btf, 8);
74044ad23dfSAndrii Nakryiko 		break;
74144ad23dfSAndrii Nakryiko 	default:
74244ad23dfSAndrii Nakryiko 		pr_warn("failed to get ELF class (bitness) for %s\n", path);
74344ad23dfSAndrii Nakryiko 		break;
74444ad23dfSAndrii Nakryiko 	}
74544ad23dfSAndrii Nakryiko 
746e6c64855SAndrii Nakryiko 	if (btf_ext && btf_ext_data) {
747e6c64855SAndrii Nakryiko 		*btf_ext = btf_ext__new(btf_ext_data->d_buf,
748e6c64855SAndrii Nakryiko 					btf_ext_data->d_size);
749e6c64855SAndrii Nakryiko 		if (IS_ERR(*btf_ext))
750e6c64855SAndrii Nakryiko 			goto done;
751e6c64855SAndrii Nakryiko 	} else if (btf_ext) {
752e6c64855SAndrii Nakryiko 		*btf_ext = NULL;
753e6c64855SAndrii Nakryiko 	}
754e6c64855SAndrii Nakryiko done:
755e6c64855SAndrii Nakryiko 	if (elf)
756e6c64855SAndrii Nakryiko 		elf_end(elf);
757e6c64855SAndrii Nakryiko 	close(fd);
758e6c64855SAndrii Nakryiko 
759e6c64855SAndrii Nakryiko 	if (err)
760e6c64855SAndrii Nakryiko 		return ERR_PTR(err);
761e6c64855SAndrii Nakryiko 	/*
762e6c64855SAndrii Nakryiko 	 * btf is always parsed before btf_ext, so no need to clean up
763e6c64855SAndrii Nakryiko 	 * btf_ext, if btf loading failed
764e6c64855SAndrii Nakryiko 	 */
765e6c64855SAndrii Nakryiko 	if (IS_ERR(btf))
766e6c64855SAndrii Nakryiko 		return btf;
767e6c64855SAndrii Nakryiko 	if (btf_ext && IS_ERR(*btf_ext)) {
768e6c64855SAndrii Nakryiko 		btf__free(btf);
769e6c64855SAndrii Nakryiko 		err = PTR_ERR(*btf_ext);
770e6c64855SAndrii Nakryiko 		return ERR_PTR(err);
771e6c64855SAndrii Nakryiko 	}
772e6c64855SAndrii Nakryiko 	return btf;
773e6c64855SAndrii Nakryiko }
774e6c64855SAndrii Nakryiko 
77594a1feddSAndrii Nakryiko struct btf *btf__parse_raw(const char *path)
77694a1feddSAndrii Nakryiko {
777932ac54aSDaniel T. Lee 	struct btf *btf = NULL;
77894a1feddSAndrii Nakryiko 	void *data = NULL;
77994a1feddSAndrii Nakryiko 	FILE *f = NULL;
78094a1feddSAndrii Nakryiko 	__u16 magic;
78194a1feddSAndrii Nakryiko 	int err = 0;
78294a1feddSAndrii Nakryiko 	long sz;
78394a1feddSAndrii Nakryiko 
78494a1feddSAndrii Nakryiko 	f = fopen(path, "rb");
78594a1feddSAndrii Nakryiko 	if (!f) {
78694a1feddSAndrii Nakryiko 		err = -errno;
78794a1feddSAndrii Nakryiko 		goto err_out;
78894a1feddSAndrii Nakryiko 	}
78994a1feddSAndrii Nakryiko 
79094a1feddSAndrii Nakryiko 	/* check BTF magic */
79194a1feddSAndrii Nakryiko 	if (fread(&magic, 1, sizeof(magic), f) < sizeof(magic)) {
79294a1feddSAndrii Nakryiko 		err = -EIO;
79394a1feddSAndrii Nakryiko 		goto err_out;
79494a1feddSAndrii Nakryiko 	}
79594a1feddSAndrii Nakryiko 	if (magic != BTF_MAGIC) {
79694a1feddSAndrii Nakryiko 		/* definitely not a raw BTF */
79794a1feddSAndrii Nakryiko 		err = -EPROTO;
79894a1feddSAndrii Nakryiko 		goto err_out;
79994a1feddSAndrii Nakryiko 	}
80094a1feddSAndrii Nakryiko 
80194a1feddSAndrii Nakryiko 	/* get file size */
80294a1feddSAndrii Nakryiko 	if (fseek(f, 0, SEEK_END)) {
80394a1feddSAndrii Nakryiko 		err = -errno;
80494a1feddSAndrii Nakryiko 		goto err_out;
80594a1feddSAndrii Nakryiko 	}
80694a1feddSAndrii Nakryiko 	sz = ftell(f);
80794a1feddSAndrii Nakryiko 	if (sz < 0) {
80894a1feddSAndrii Nakryiko 		err = -errno;
80994a1feddSAndrii Nakryiko 		goto err_out;
81094a1feddSAndrii Nakryiko 	}
81194a1feddSAndrii Nakryiko 	/* rewind to the start */
81294a1feddSAndrii Nakryiko 	if (fseek(f, 0, SEEK_SET)) {
81394a1feddSAndrii Nakryiko 		err = -errno;
81494a1feddSAndrii Nakryiko 		goto err_out;
81594a1feddSAndrii Nakryiko 	}
81694a1feddSAndrii Nakryiko 
81794a1feddSAndrii Nakryiko 	/* pre-alloc memory and read all of BTF data */
81894a1feddSAndrii Nakryiko 	data = malloc(sz);
81994a1feddSAndrii Nakryiko 	if (!data) {
82094a1feddSAndrii Nakryiko 		err = -ENOMEM;
82194a1feddSAndrii Nakryiko 		goto err_out;
82294a1feddSAndrii Nakryiko 	}
82394a1feddSAndrii Nakryiko 	if (fread(data, 1, sz, f) < sz) {
82494a1feddSAndrii Nakryiko 		err = -EIO;
82594a1feddSAndrii Nakryiko 		goto err_out;
82694a1feddSAndrii Nakryiko 	}
82794a1feddSAndrii Nakryiko 
82894a1feddSAndrii Nakryiko 	/* finally parse BTF data */
82994a1feddSAndrii Nakryiko 	btf = btf__new(data, sz);
83094a1feddSAndrii Nakryiko 
83194a1feddSAndrii Nakryiko err_out:
83294a1feddSAndrii Nakryiko 	free(data);
83394a1feddSAndrii Nakryiko 	if (f)
83494a1feddSAndrii Nakryiko 		fclose(f);
83594a1feddSAndrii Nakryiko 	return err ? ERR_PTR(err) : btf;
83694a1feddSAndrii Nakryiko }
83794a1feddSAndrii Nakryiko 
83894a1feddSAndrii Nakryiko struct btf *btf__parse(const char *path, struct btf_ext **btf_ext)
83994a1feddSAndrii Nakryiko {
84094a1feddSAndrii Nakryiko 	struct btf *btf;
84194a1feddSAndrii Nakryiko 
84294a1feddSAndrii Nakryiko 	if (btf_ext)
84394a1feddSAndrii Nakryiko 		*btf_ext = NULL;
84494a1feddSAndrii Nakryiko 
84594a1feddSAndrii Nakryiko 	btf = btf__parse_raw(path);
84694a1feddSAndrii Nakryiko 	if (!IS_ERR(btf) || PTR_ERR(btf) != -EPROTO)
84794a1feddSAndrii Nakryiko 		return btf;
84894a1feddSAndrii Nakryiko 
84994a1feddSAndrii Nakryiko 	return btf__parse_elf(path, btf_ext);
85094a1feddSAndrii Nakryiko }
85194a1feddSAndrii Nakryiko 
8521713d68bSDaniel Borkmann static int compare_vsi_off(const void *_a, const void *_b)
8531713d68bSDaniel Borkmann {
8541713d68bSDaniel Borkmann 	const struct btf_var_secinfo *a = _a;
8551713d68bSDaniel Borkmann 	const struct btf_var_secinfo *b = _b;
8561713d68bSDaniel Borkmann 
8571713d68bSDaniel Borkmann 	return a->offset - b->offset;
8581713d68bSDaniel Borkmann }
8591713d68bSDaniel Borkmann 
8601713d68bSDaniel Borkmann static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf,
8611713d68bSDaniel Borkmann 			     struct btf_type *t)
8621713d68bSDaniel Borkmann {
863b03bc685SAndrii Nakryiko 	__u32 size = 0, off = 0, i, vars = btf_vlen(t);
8641713d68bSDaniel Borkmann 	const char *name = btf__name_by_offset(btf, t->name_off);
8651713d68bSDaniel Borkmann 	const struct btf_type *t_var;
8661713d68bSDaniel Borkmann 	struct btf_var_secinfo *vsi;
867b03bc685SAndrii Nakryiko 	const struct btf_var *var;
8681713d68bSDaniel Borkmann 	int ret;
8691713d68bSDaniel Borkmann 
8701713d68bSDaniel Borkmann 	if (!name) {
8711713d68bSDaniel Borkmann 		pr_debug("No name found in string section for DATASEC kind.\n");
8721713d68bSDaniel Borkmann 		return -ENOENT;
8731713d68bSDaniel Borkmann 	}
8741713d68bSDaniel Borkmann 
875166750bcSAndrii Nakryiko 	/* .extern datasec size and var offsets were set correctly during
876166750bcSAndrii Nakryiko 	 * extern collection step, so just skip straight to sorting variables
877166750bcSAndrii Nakryiko 	 */
878166750bcSAndrii Nakryiko 	if (t->size)
879166750bcSAndrii Nakryiko 		goto sort_vars;
880166750bcSAndrii Nakryiko 
8811713d68bSDaniel Borkmann 	ret = bpf_object__section_size(obj, name, &size);
8821713d68bSDaniel Borkmann 	if (ret || !size || (t->size && t->size != size)) {
8831713d68bSDaniel Borkmann 		pr_debug("Invalid size for section %s: %u bytes\n", name, size);
8841713d68bSDaniel Borkmann 		return -ENOENT;
8851713d68bSDaniel Borkmann 	}
8861713d68bSDaniel Borkmann 
8871713d68bSDaniel Borkmann 	t->size = size;
8881713d68bSDaniel Borkmann 
889b03bc685SAndrii Nakryiko 	for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) {
8901713d68bSDaniel Borkmann 		t_var = btf__type_by_id(btf, vsi->type);
891b03bc685SAndrii Nakryiko 		var = btf_var(t_var);
8921713d68bSDaniel Borkmann 
893b03bc685SAndrii Nakryiko 		if (!btf_is_var(t_var)) {
8941713d68bSDaniel Borkmann 			pr_debug("Non-VAR type seen in section %s\n", name);
8951713d68bSDaniel Borkmann 			return -EINVAL;
8961713d68bSDaniel Borkmann 		}
8971713d68bSDaniel Borkmann 
8981713d68bSDaniel Borkmann 		if (var->linkage == BTF_VAR_STATIC)
8991713d68bSDaniel Borkmann 			continue;
9001713d68bSDaniel Borkmann 
9011713d68bSDaniel Borkmann 		name = btf__name_by_offset(btf, t_var->name_off);
9021713d68bSDaniel Borkmann 		if (!name) {
9031713d68bSDaniel Borkmann 			pr_debug("No name found in string section for VAR kind\n");
9041713d68bSDaniel Borkmann 			return -ENOENT;
9051713d68bSDaniel Borkmann 		}
9061713d68bSDaniel Borkmann 
9071713d68bSDaniel Borkmann 		ret = bpf_object__variable_offset(obj, name, &off);
9081713d68bSDaniel Borkmann 		if (ret) {
909b03bc685SAndrii Nakryiko 			pr_debug("No offset found in symbol table for VAR %s\n",
910b03bc685SAndrii Nakryiko 				 name);
9111713d68bSDaniel Borkmann 			return -ENOENT;
9121713d68bSDaniel Borkmann 		}
9131713d68bSDaniel Borkmann 
9141713d68bSDaniel Borkmann 		vsi->offset = off;
9151713d68bSDaniel Borkmann 	}
9161713d68bSDaniel Borkmann 
917166750bcSAndrii Nakryiko sort_vars:
918166750bcSAndrii Nakryiko 	qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off);
9191713d68bSDaniel Borkmann 	return 0;
9201713d68bSDaniel Borkmann }
9211713d68bSDaniel Borkmann 
9221713d68bSDaniel Borkmann int btf__finalize_data(struct bpf_object *obj, struct btf *btf)
9231713d68bSDaniel Borkmann {
9241713d68bSDaniel Borkmann 	int err = 0;
9251713d68bSDaniel Borkmann 	__u32 i;
9261713d68bSDaniel Borkmann 
9271713d68bSDaniel Borkmann 	for (i = 1; i <= btf->nr_types; i++) {
928740e69c3SAndrii Nakryiko 		struct btf_type *t = btf_type_by_id(btf, i);
9291713d68bSDaniel Borkmann 
9301713d68bSDaniel Borkmann 		/* Loader needs to fix up some of the things compiler
9311713d68bSDaniel Borkmann 		 * couldn't get its hands on while emitting BTF. This
9321713d68bSDaniel Borkmann 		 * is section size and global variable offset. We use
9331713d68bSDaniel Borkmann 		 * the info from the ELF itself for this purpose.
9341713d68bSDaniel Borkmann 		 */
935b03bc685SAndrii Nakryiko 		if (btf_is_datasec(t)) {
9361713d68bSDaniel Borkmann 			err = btf_fixup_datasec(obj, btf, t);
9371713d68bSDaniel Borkmann 			if (err)
9381713d68bSDaniel Borkmann 				break;
9391713d68bSDaniel Borkmann 		}
9401713d68bSDaniel Borkmann 	}
9411713d68bSDaniel Borkmann 
9421713d68bSDaniel Borkmann 	return err;
9431713d68bSDaniel Borkmann }
9441713d68bSDaniel Borkmann 
945d29d87f7SAndrii Nakryiko int btf__load(struct btf *btf)
946d29d87f7SAndrii Nakryiko {
947b8604247SAndrii Nakryiko 	__u32 log_buf_size = 0, raw_size;
948d29d87f7SAndrii Nakryiko 	char *log_buf = NULL;
949b8604247SAndrii Nakryiko 	const void *raw_data;
950d29d87f7SAndrii Nakryiko 	int err = 0;
951d29d87f7SAndrii Nakryiko 
952d29d87f7SAndrii Nakryiko 	if (btf->fd >= 0)
953d29d87f7SAndrii Nakryiko 		return -EEXIST;
954d29d87f7SAndrii Nakryiko 
9558395f320SStanislav Fomichev retry_load:
9568395f320SStanislav Fomichev 	if (log_buf_size) {
957d29d87f7SAndrii Nakryiko 		log_buf = malloc(log_buf_size);
958d29d87f7SAndrii Nakryiko 		if (!log_buf)
959d29d87f7SAndrii Nakryiko 			return -ENOMEM;
960d29d87f7SAndrii Nakryiko 
961d29d87f7SAndrii Nakryiko 		*log_buf = 0;
9628395f320SStanislav Fomichev 	}
963d29d87f7SAndrii Nakryiko 
964b8604247SAndrii Nakryiko 	raw_data = btf__get_raw_data(btf, &raw_size);
965b8604247SAndrii Nakryiko 	if (!raw_data) {
966b8604247SAndrii Nakryiko 		err = -ENOMEM;
967b8604247SAndrii Nakryiko 		goto done;
968b8604247SAndrii Nakryiko 	}
969b8604247SAndrii Nakryiko 
970b8604247SAndrii Nakryiko 	btf->fd = bpf_load_btf(raw_data, raw_size, log_buf, log_buf_size, false);
971d29d87f7SAndrii Nakryiko 	if (btf->fd < 0) {
9728395f320SStanislav Fomichev 		if (!log_buf || errno == ENOSPC) {
9738395f320SStanislav Fomichev 			log_buf_size = max((__u32)BPF_LOG_BUF_SIZE,
9748395f320SStanislav Fomichev 					   log_buf_size << 1);
9758395f320SStanislav Fomichev 			free(log_buf);
9768395f320SStanislav Fomichev 			goto retry_load;
9778395f320SStanislav Fomichev 		}
9788395f320SStanislav Fomichev 
979d29d87f7SAndrii Nakryiko 		err = -errno;
980be18010eSKefeng Wang 		pr_warn("Error loading BTF: %s(%d)\n", strerror(errno), errno);
981d29d87f7SAndrii Nakryiko 		if (*log_buf)
982be18010eSKefeng Wang 			pr_warn("%s\n", log_buf);
983d29d87f7SAndrii Nakryiko 		goto done;
984d29d87f7SAndrii Nakryiko 	}
985d29d87f7SAndrii Nakryiko 
986d29d87f7SAndrii Nakryiko done:
987d29d87f7SAndrii Nakryiko 	free(log_buf);
988d29d87f7SAndrii Nakryiko 	return err;
989d29d87f7SAndrii Nakryiko }
990d29d87f7SAndrii Nakryiko 
9918a138aedSMartin KaFai Lau int btf__fd(const struct btf *btf)
9928a138aedSMartin KaFai Lau {
9938a138aedSMartin KaFai Lau 	return btf->fd;
9948a138aedSMartin KaFai Lau }
99592b57121SOkash Khawaja 
99681372e12SAndrii Nakryiko void btf__set_fd(struct btf *btf, int fd)
99781372e12SAndrii Nakryiko {
99881372e12SAndrii Nakryiko 	btf->fd = fd;
99981372e12SAndrii Nakryiko }
100081372e12SAndrii Nakryiko 
1001919d2b1dSAndrii Nakryiko const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size)
100202c87446SAndrii Nakryiko {
1003919d2b1dSAndrii Nakryiko 	struct btf *btf = (struct btf *)btf_ro;
1004919d2b1dSAndrii Nakryiko 
1005919d2b1dSAndrii Nakryiko 	if (!btf->raw_data) {
1006919d2b1dSAndrii Nakryiko 		struct btf_header *hdr = btf->hdr;
1007919d2b1dSAndrii Nakryiko 		void *data;
1008919d2b1dSAndrii Nakryiko 
1009919d2b1dSAndrii Nakryiko 		btf->raw_size = hdr->hdr_len + hdr->type_len + hdr->str_len;
1010919d2b1dSAndrii Nakryiko 		btf->raw_data = calloc(1, btf->raw_size);
1011919d2b1dSAndrii Nakryiko 		if (!btf->raw_data)
1012919d2b1dSAndrii Nakryiko 			return NULL;
1013919d2b1dSAndrii Nakryiko 		data = btf->raw_data;
1014919d2b1dSAndrii Nakryiko 
1015919d2b1dSAndrii Nakryiko 		memcpy(data, hdr, hdr->hdr_len);
1016919d2b1dSAndrii Nakryiko 		data += hdr->hdr_len;
1017919d2b1dSAndrii Nakryiko 
1018919d2b1dSAndrii Nakryiko 		memcpy(data, btf->types_data, hdr->type_len);
1019919d2b1dSAndrii Nakryiko 		data += hdr->type_len;
1020919d2b1dSAndrii Nakryiko 
1021919d2b1dSAndrii Nakryiko 		memcpy(data, btf->strs_data, hdr->str_len);
1022919d2b1dSAndrii Nakryiko 		data += hdr->str_len;
1023919d2b1dSAndrii Nakryiko 	}
1024b8604247SAndrii Nakryiko 	*size = btf->raw_size;
1025b8604247SAndrii Nakryiko 	return btf->raw_data;
102602c87446SAndrii Nakryiko }
102702c87446SAndrii Nakryiko 
102892b57121SOkash Khawaja const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
102992b57121SOkash Khawaja {
103092b57121SOkash Khawaja 	if (offset < btf->hdr->str_len)
1031b8604247SAndrii Nakryiko 		return btf->strs_data + offset;
103292b57121SOkash Khawaja 	else
103392b57121SOkash Khawaja 		return NULL;
103492b57121SOkash Khawaja }
10352993e051SYonghong Song 
10361d2f44caSMartin KaFai Lau int btf__get_from_id(__u32 id, struct btf **btf)
1037d7f5b5e0SYonghong Song {
1038d7f5b5e0SYonghong Song 	struct bpf_btf_info btf_info = { 0 };
1039d7f5b5e0SYonghong Song 	__u32 len = sizeof(btf_info);
1040d7f5b5e0SYonghong Song 	__u32 last_size;
1041d7f5b5e0SYonghong Song 	int btf_fd;
1042d7f5b5e0SYonghong Song 	void *ptr;
1043d7f5b5e0SYonghong Song 	int err;
1044d7f5b5e0SYonghong Song 
1045d7f5b5e0SYonghong Song 	err = 0;
1046d7f5b5e0SYonghong Song 	*btf = NULL;
1047d7f5b5e0SYonghong Song 	btf_fd = bpf_btf_get_fd_by_id(id);
1048d7f5b5e0SYonghong Song 	if (btf_fd < 0)
1049d7f5b5e0SYonghong Song 		return 0;
1050d7f5b5e0SYonghong Song 
1051d7f5b5e0SYonghong Song 	/* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
1052d7f5b5e0SYonghong Song 	 * let's start with a sane default - 4KiB here - and resize it only if
1053d7f5b5e0SYonghong Song 	 * bpf_obj_get_info_by_fd() needs a bigger buffer.
1054d7f5b5e0SYonghong Song 	 */
1055d7f5b5e0SYonghong Song 	btf_info.btf_size = 4096;
1056d7f5b5e0SYonghong Song 	last_size = btf_info.btf_size;
1057d7f5b5e0SYonghong Song 	ptr = malloc(last_size);
1058d7f5b5e0SYonghong Song 	if (!ptr) {
1059d7f5b5e0SYonghong Song 		err = -ENOMEM;
1060d7f5b5e0SYonghong Song 		goto exit_free;
1061d7f5b5e0SYonghong Song 	}
1062d7f5b5e0SYonghong Song 
10631ad9cbb8SAndrii Nakryiko 	memset(ptr, 0, last_size);
1064d7f5b5e0SYonghong Song 	btf_info.btf = ptr_to_u64(ptr);
1065d7f5b5e0SYonghong Song 	err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
1066d7f5b5e0SYonghong Song 
1067d7f5b5e0SYonghong Song 	if (!err && btf_info.btf_size > last_size) {
1068d7f5b5e0SYonghong Song 		void *temp_ptr;
1069d7f5b5e0SYonghong Song 
1070d7f5b5e0SYonghong Song 		last_size = btf_info.btf_size;
1071d7f5b5e0SYonghong Song 		temp_ptr = realloc(ptr, last_size);
1072d7f5b5e0SYonghong Song 		if (!temp_ptr) {
1073d7f5b5e0SYonghong Song 			err = -ENOMEM;
1074d7f5b5e0SYonghong Song 			goto exit_free;
1075d7f5b5e0SYonghong Song 		}
1076d7f5b5e0SYonghong Song 		ptr = temp_ptr;
10771ad9cbb8SAndrii Nakryiko 		memset(ptr, 0, last_size);
1078d7f5b5e0SYonghong Song 		btf_info.btf = ptr_to_u64(ptr);
1079d7f5b5e0SYonghong Song 		err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
1080d7f5b5e0SYonghong Song 	}
1081d7f5b5e0SYonghong Song 
1082d7f5b5e0SYonghong Song 	if (err || btf_info.btf_size > last_size) {
1083d7f5b5e0SYonghong Song 		err = errno;
1084d7f5b5e0SYonghong Song 		goto exit_free;
1085d7f5b5e0SYonghong Song 	}
1086d7f5b5e0SYonghong Song 
10878461ef8bSYonghong Song 	*btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size);
1088d7f5b5e0SYonghong Song 	if (IS_ERR(*btf)) {
1089d7f5b5e0SYonghong Song 		err = PTR_ERR(*btf);
1090d7f5b5e0SYonghong Song 		*btf = NULL;
1091d7f5b5e0SYonghong Song 	}
1092d7f5b5e0SYonghong Song 
1093d7f5b5e0SYonghong Song exit_free:
1094d7f5b5e0SYonghong Song 	close(btf_fd);
1095d7f5b5e0SYonghong Song 	free(ptr);
1096d7f5b5e0SYonghong Song 
1097d7f5b5e0SYonghong Song 	return err;
1098d7f5b5e0SYonghong Song }
1099d7f5b5e0SYonghong Song 
1100a6c109a6SYonghong Song int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
110196408c43SYonghong Song 			 __u32 expected_key_size, __u32 expected_value_size,
110296408c43SYonghong Song 			 __u32 *key_type_id, __u32 *value_type_id)
110396408c43SYonghong Song {
110496408c43SYonghong Song 	const struct btf_type *container_type;
110596408c43SYonghong Song 	const struct btf_member *key, *value;
110696408c43SYonghong Song 	const size_t max_name = 256;
110796408c43SYonghong Song 	char container_name[max_name];
110896408c43SYonghong Song 	__s64 key_size, value_size;
110996408c43SYonghong Song 	__s32 container_id;
111096408c43SYonghong Song 
111196408c43SYonghong Song 	if (snprintf(container_name, max_name, "____btf_map_%s", map_name) ==
111296408c43SYonghong Song 	    max_name) {
1113be18010eSKefeng Wang 		pr_warn("map:%s length of '____btf_map_%s' is too long\n",
111496408c43SYonghong Song 			map_name, map_name);
111596408c43SYonghong Song 		return -EINVAL;
111696408c43SYonghong Song 	}
111796408c43SYonghong Song 
111896408c43SYonghong Song 	container_id = btf__find_by_name(btf, container_name);
111996408c43SYonghong Song 	if (container_id < 0) {
1120f7748e29SYonghong Song 		pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n",
112196408c43SYonghong Song 			 map_name, container_name);
112296408c43SYonghong Song 		return container_id;
112396408c43SYonghong Song 	}
112496408c43SYonghong Song 
112596408c43SYonghong Song 	container_type = btf__type_by_id(btf, container_id);
112696408c43SYonghong Song 	if (!container_type) {
1127be18010eSKefeng Wang 		pr_warn("map:%s cannot find BTF type for container_id:%u\n",
112896408c43SYonghong Song 			map_name, container_id);
112996408c43SYonghong Song 		return -EINVAL;
113096408c43SYonghong Song 	}
113196408c43SYonghong Song 
1132b03bc685SAndrii Nakryiko 	if (!btf_is_struct(container_type) || btf_vlen(container_type) < 2) {
1133be18010eSKefeng Wang 		pr_warn("map:%s container_name:%s is an invalid container struct\n",
113496408c43SYonghong Song 			map_name, container_name);
113596408c43SYonghong Song 		return -EINVAL;
113696408c43SYonghong Song 	}
113796408c43SYonghong Song 
1138b03bc685SAndrii Nakryiko 	key = btf_members(container_type);
113996408c43SYonghong Song 	value = key + 1;
114096408c43SYonghong Song 
114196408c43SYonghong Song 	key_size = btf__resolve_size(btf, key->type);
114296408c43SYonghong Song 	if (key_size < 0) {
1143be18010eSKefeng Wang 		pr_warn("map:%s invalid BTF key_type_size\n", map_name);
114496408c43SYonghong Song 		return key_size;
114596408c43SYonghong Song 	}
114696408c43SYonghong Song 
114796408c43SYonghong Song 	if (expected_key_size != key_size) {
1148be18010eSKefeng Wang 		pr_warn("map:%s btf_key_type_size:%u != map_def_key_size:%u\n",
114996408c43SYonghong Song 			map_name, (__u32)key_size, expected_key_size);
115096408c43SYonghong Song 		return -EINVAL;
115196408c43SYonghong Song 	}
115296408c43SYonghong Song 
115396408c43SYonghong Song 	value_size = btf__resolve_size(btf, value->type);
115496408c43SYonghong Song 	if (value_size < 0) {
1155be18010eSKefeng Wang 		pr_warn("map:%s invalid BTF value_type_size\n", map_name);
115696408c43SYonghong Song 		return value_size;
115796408c43SYonghong Song 	}
115896408c43SYonghong Song 
115996408c43SYonghong Song 	if (expected_value_size != value_size) {
1160be18010eSKefeng Wang 		pr_warn("map:%s btf_value_type_size:%u != map_def_value_size:%u\n",
116196408c43SYonghong Song 			map_name, (__u32)value_size, expected_value_size);
116296408c43SYonghong Song 		return -EINVAL;
116396408c43SYonghong Song 	}
116496408c43SYonghong Song 
116596408c43SYonghong Song 	*key_type_id = key->type;
116696408c43SYonghong Song 	*value_type_id = value->type;
116796408c43SYonghong Song 
116896408c43SYonghong Song 	return 0;
116996408c43SYonghong Song }
117096408c43SYonghong Song 
1171919d2b1dSAndrii Nakryiko static size_t strs_hash_fn(const void *key, void *ctx)
1172919d2b1dSAndrii Nakryiko {
1173919d2b1dSAndrii Nakryiko 	struct btf *btf = ctx;
1174919d2b1dSAndrii Nakryiko 	const char *str = btf->strs_data + (long)key;
1175919d2b1dSAndrii Nakryiko 
1176919d2b1dSAndrii Nakryiko 	return str_hash(str);
1177919d2b1dSAndrii Nakryiko }
1178919d2b1dSAndrii Nakryiko 
1179919d2b1dSAndrii Nakryiko static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx)
1180919d2b1dSAndrii Nakryiko {
1181919d2b1dSAndrii Nakryiko 	struct btf *btf = ctx;
1182919d2b1dSAndrii Nakryiko 	const char *str1 = btf->strs_data + (long)key1;
1183919d2b1dSAndrii Nakryiko 	const char *str2 = btf->strs_data + (long)key2;
1184919d2b1dSAndrii Nakryiko 
1185919d2b1dSAndrii Nakryiko 	return strcmp(str1, str2) == 0;
1186919d2b1dSAndrii Nakryiko }
1187919d2b1dSAndrii Nakryiko 
1188919d2b1dSAndrii Nakryiko /* Ensure BTF is ready to be modified (by splitting into a three memory
1189919d2b1dSAndrii Nakryiko  * regions for header, types, and strings). Also invalidate cached
1190919d2b1dSAndrii Nakryiko  * raw_data, if any.
1191919d2b1dSAndrii Nakryiko  */
1192919d2b1dSAndrii Nakryiko static int btf_ensure_modifiable(struct btf *btf)
1193919d2b1dSAndrii Nakryiko {
1194919d2b1dSAndrii Nakryiko 	void *hdr, *types, *strs, *strs_end, *s;
1195919d2b1dSAndrii Nakryiko 	struct hashmap *hash = NULL;
1196919d2b1dSAndrii Nakryiko 	long off;
1197919d2b1dSAndrii Nakryiko 	int err;
1198919d2b1dSAndrii Nakryiko 
1199919d2b1dSAndrii Nakryiko 	if (btf_is_modifiable(btf)) {
1200919d2b1dSAndrii Nakryiko 		/* any BTF modification invalidates raw_data */
1201919d2b1dSAndrii Nakryiko 		if (btf->raw_data) {
1202919d2b1dSAndrii Nakryiko 			free(btf->raw_data);
1203919d2b1dSAndrii Nakryiko 			btf->raw_data = NULL;
1204919d2b1dSAndrii Nakryiko 		}
1205919d2b1dSAndrii Nakryiko 		return 0;
1206919d2b1dSAndrii Nakryiko 	}
1207919d2b1dSAndrii Nakryiko 
1208919d2b1dSAndrii Nakryiko 	/* split raw data into three memory regions */
1209919d2b1dSAndrii Nakryiko 	hdr = malloc(btf->hdr->hdr_len);
1210919d2b1dSAndrii Nakryiko 	types = malloc(btf->hdr->type_len);
1211919d2b1dSAndrii Nakryiko 	strs = malloc(btf->hdr->str_len);
1212919d2b1dSAndrii Nakryiko 	if (!hdr || !types || !strs)
1213919d2b1dSAndrii Nakryiko 		goto err_out;
1214919d2b1dSAndrii Nakryiko 
1215919d2b1dSAndrii Nakryiko 	memcpy(hdr, btf->hdr, btf->hdr->hdr_len);
1216919d2b1dSAndrii Nakryiko 	memcpy(types, btf->types_data, btf->hdr->type_len);
1217919d2b1dSAndrii Nakryiko 	memcpy(strs, btf->strs_data, btf->hdr->str_len);
1218919d2b1dSAndrii Nakryiko 
1219919d2b1dSAndrii Nakryiko 	/* build lookup index for all strings */
1220919d2b1dSAndrii Nakryiko 	hash = hashmap__new(strs_hash_fn, strs_hash_equal_fn, btf);
1221919d2b1dSAndrii Nakryiko 	if (IS_ERR(hash)) {
1222919d2b1dSAndrii Nakryiko 		err = PTR_ERR(hash);
1223919d2b1dSAndrii Nakryiko 		hash = NULL;
1224919d2b1dSAndrii Nakryiko 		goto err_out;
1225919d2b1dSAndrii Nakryiko 	}
1226919d2b1dSAndrii Nakryiko 
1227919d2b1dSAndrii Nakryiko 	strs_end = strs + btf->hdr->str_len;
1228919d2b1dSAndrii Nakryiko 	for (off = 0, s = strs; s < strs_end; off += strlen(s) + 1, s = strs + off) {
1229919d2b1dSAndrii Nakryiko 		/* hashmap__add() returns EEXIST if string with the same
1230919d2b1dSAndrii Nakryiko 		 * content already is in the hash map
1231919d2b1dSAndrii Nakryiko 		 */
1232919d2b1dSAndrii Nakryiko 		err = hashmap__add(hash, (void *)off, (void *)off);
1233919d2b1dSAndrii Nakryiko 		if (err == -EEXIST)
1234919d2b1dSAndrii Nakryiko 			continue; /* duplicate */
1235919d2b1dSAndrii Nakryiko 		if (err)
1236919d2b1dSAndrii Nakryiko 			goto err_out;
1237919d2b1dSAndrii Nakryiko 	}
1238919d2b1dSAndrii Nakryiko 
1239919d2b1dSAndrii Nakryiko 	/* only when everything was successful, update internal state */
1240919d2b1dSAndrii Nakryiko 	btf->hdr = hdr;
1241919d2b1dSAndrii Nakryiko 	btf->types_data = types;
1242919d2b1dSAndrii Nakryiko 	btf->types_data_cap = btf->hdr->type_len;
1243919d2b1dSAndrii Nakryiko 	btf->strs_data = strs;
1244919d2b1dSAndrii Nakryiko 	btf->strs_data_cap = btf->hdr->str_len;
1245919d2b1dSAndrii Nakryiko 	btf->strs_hash = hash;
1246919d2b1dSAndrii Nakryiko 	/* if BTF was created from scratch, all strings are guaranteed to be
1247919d2b1dSAndrii Nakryiko 	 * unique and deduplicated
1248919d2b1dSAndrii Nakryiko 	 */
1249919d2b1dSAndrii Nakryiko 	btf->strs_deduped = btf->hdr->str_len <= 1;
1250919d2b1dSAndrii Nakryiko 
1251919d2b1dSAndrii Nakryiko 	/* invalidate raw_data representation */
1252919d2b1dSAndrii Nakryiko 	free(btf->raw_data);
1253919d2b1dSAndrii Nakryiko 	btf->raw_data = NULL;
1254919d2b1dSAndrii Nakryiko 
1255919d2b1dSAndrii Nakryiko 	return 0;
1256919d2b1dSAndrii Nakryiko 
1257919d2b1dSAndrii Nakryiko err_out:
1258919d2b1dSAndrii Nakryiko 	hashmap__free(hash);
1259919d2b1dSAndrii Nakryiko 	free(hdr);
1260919d2b1dSAndrii Nakryiko 	free(types);
1261919d2b1dSAndrii Nakryiko 	free(strs);
1262919d2b1dSAndrii Nakryiko 	return -ENOMEM;
1263919d2b1dSAndrii Nakryiko }
1264919d2b1dSAndrii Nakryiko 
1265919d2b1dSAndrii Nakryiko static void *btf_add_str_mem(struct btf *btf, size_t add_sz)
1266919d2b1dSAndrii Nakryiko {
1267919d2b1dSAndrii Nakryiko 	return btf_add_mem(&btf->strs_data, &btf->strs_data_cap, 1,
1268919d2b1dSAndrii Nakryiko 			   btf->hdr->str_len, BTF_MAX_STR_OFFSET, add_sz);
1269919d2b1dSAndrii Nakryiko }
1270919d2b1dSAndrii Nakryiko 
1271919d2b1dSAndrii Nakryiko /* Find an offset in BTF string section that corresponds to a given string *s*.
1272919d2b1dSAndrii Nakryiko  * Returns:
1273919d2b1dSAndrii Nakryiko  *   - >0 offset into string section, if string is found;
1274919d2b1dSAndrii Nakryiko  *   - -ENOENT, if string is not in the string section;
1275919d2b1dSAndrii Nakryiko  *   - <0, on any other error.
1276919d2b1dSAndrii Nakryiko  */
1277919d2b1dSAndrii Nakryiko int btf__find_str(struct btf *btf, const char *s)
1278919d2b1dSAndrii Nakryiko {
1279919d2b1dSAndrii Nakryiko 	long old_off, new_off, len;
1280919d2b1dSAndrii Nakryiko 	void *p;
1281919d2b1dSAndrii Nakryiko 
1282919d2b1dSAndrii Nakryiko 	/* BTF needs to be in a modifiable state to build string lookup index */
1283919d2b1dSAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1284919d2b1dSAndrii Nakryiko 		return -ENOMEM;
1285919d2b1dSAndrii Nakryiko 
1286919d2b1dSAndrii Nakryiko 	/* see btf__add_str() for why we do this */
1287919d2b1dSAndrii Nakryiko 	len = strlen(s) + 1;
1288919d2b1dSAndrii Nakryiko 	p = btf_add_str_mem(btf, len);
1289919d2b1dSAndrii Nakryiko 	if (!p)
1290919d2b1dSAndrii Nakryiko 		return -ENOMEM;
1291919d2b1dSAndrii Nakryiko 
1292919d2b1dSAndrii Nakryiko 	new_off = btf->hdr->str_len;
1293919d2b1dSAndrii Nakryiko 	memcpy(p, s, len);
1294919d2b1dSAndrii Nakryiko 
1295919d2b1dSAndrii Nakryiko 	if (hashmap__find(btf->strs_hash, (void *)new_off, (void **)&old_off))
1296919d2b1dSAndrii Nakryiko 		return old_off;
1297919d2b1dSAndrii Nakryiko 
1298919d2b1dSAndrii Nakryiko 	return -ENOENT;
1299919d2b1dSAndrii Nakryiko }
1300919d2b1dSAndrii Nakryiko 
1301919d2b1dSAndrii Nakryiko /* Add a string s to the BTF string section.
1302919d2b1dSAndrii Nakryiko  * Returns:
1303919d2b1dSAndrii Nakryiko  *   - > 0 offset into string section, on success;
1304919d2b1dSAndrii Nakryiko  *   - < 0, on error.
1305919d2b1dSAndrii Nakryiko  */
1306919d2b1dSAndrii Nakryiko int btf__add_str(struct btf *btf, const char *s)
1307919d2b1dSAndrii Nakryiko {
1308919d2b1dSAndrii Nakryiko 	long old_off, new_off, len;
1309919d2b1dSAndrii Nakryiko 	void *p;
1310919d2b1dSAndrii Nakryiko 	int err;
1311919d2b1dSAndrii Nakryiko 
1312919d2b1dSAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1313919d2b1dSAndrii Nakryiko 		return -ENOMEM;
1314919d2b1dSAndrii Nakryiko 
1315919d2b1dSAndrii Nakryiko 	/* Hashmap keys are always offsets within btf->strs_data, so to even
1316919d2b1dSAndrii Nakryiko 	 * look up some string from the "outside", we need to first append it
1317919d2b1dSAndrii Nakryiko 	 * at the end, so that it can be addressed with an offset. Luckily,
1318919d2b1dSAndrii Nakryiko 	 * until btf->hdr->str_len is incremented, that string is just a piece
1319919d2b1dSAndrii Nakryiko 	 * of garbage for the rest of BTF code, so no harm, no foul. On the
1320919d2b1dSAndrii Nakryiko 	 * other hand, if the string is unique, it's already appended and
1321919d2b1dSAndrii Nakryiko 	 * ready to be used, only a simple btf->hdr->str_len increment away.
1322919d2b1dSAndrii Nakryiko 	 */
1323919d2b1dSAndrii Nakryiko 	len = strlen(s) + 1;
1324919d2b1dSAndrii Nakryiko 	p = btf_add_str_mem(btf, len);
1325919d2b1dSAndrii Nakryiko 	if (!p)
1326919d2b1dSAndrii Nakryiko 		return -ENOMEM;
1327919d2b1dSAndrii Nakryiko 
1328919d2b1dSAndrii Nakryiko 	new_off = btf->hdr->str_len;
1329919d2b1dSAndrii Nakryiko 	memcpy(p, s, len);
1330919d2b1dSAndrii Nakryiko 
1331919d2b1dSAndrii Nakryiko 	/* Now attempt to add the string, but only if the string with the same
1332919d2b1dSAndrii Nakryiko 	 * contents doesn't exist already (HASHMAP_ADD strategy). If such
1333919d2b1dSAndrii Nakryiko 	 * string exists, we'll get its offset in old_off (that's old_key).
1334919d2b1dSAndrii Nakryiko 	 */
1335919d2b1dSAndrii Nakryiko 	err = hashmap__insert(btf->strs_hash, (void *)new_off, (void *)new_off,
1336919d2b1dSAndrii Nakryiko 			      HASHMAP_ADD, (const void **)&old_off, NULL);
1337919d2b1dSAndrii Nakryiko 	if (err == -EEXIST)
1338919d2b1dSAndrii Nakryiko 		return old_off; /* duplicated string, return existing offset */
1339919d2b1dSAndrii Nakryiko 	if (err)
1340919d2b1dSAndrii Nakryiko 		return err;
1341919d2b1dSAndrii Nakryiko 
1342919d2b1dSAndrii Nakryiko 	btf->hdr->str_len += len; /* new unique string, adjust data length */
1343919d2b1dSAndrii Nakryiko 	return new_off;
1344919d2b1dSAndrii Nakryiko }
1345919d2b1dSAndrii Nakryiko 
1346*4a3b33f8SAndrii Nakryiko static void *btf_add_type_mem(struct btf *btf, size_t add_sz)
1347*4a3b33f8SAndrii Nakryiko {
1348*4a3b33f8SAndrii Nakryiko 	return btf_add_mem(&btf->types_data, &btf->types_data_cap, 1,
1349*4a3b33f8SAndrii Nakryiko 			   btf->hdr->type_len, UINT_MAX, add_sz);
1350*4a3b33f8SAndrii Nakryiko }
1351*4a3b33f8SAndrii Nakryiko 
1352*4a3b33f8SAndrii Nakryiko static __u32 btf_type_info(int kind, int vlen, int kflag)
1353*4a3b33f8SAndrii Nakryiko {
1354*4a3b33f8SAndrii Nakryiko 	return (kflag << 31) | (kind << 24) | vlen;
1355*4a3b33f8SAndrii Nakryiko }
1356*4a3b33f8SAndrii Nakryiko 
1357*4a3b33f8SAndrii Nakryiko static void btf_type_inc_vlen(struct btf_type *t)
1358*4a3b33f8SAndrii Nakryiko {
1359*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t));
1360*4a3b33f8SAndrii Nakryiko }
1361*4a3b33f8SAndrii Nakryiko 
1362*4a3b33f8SAndrii Nakryiko /*
1363*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_INT type with:
1364*4a3b33f8SAndrii Nakryiko  *   - *name* - non-empty, non-NULL type name;
1365*4a3b33f8SAndrii Nakryiko  *   - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes;
1366*4a3b33f8SAndrii Nakryiko  *   - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL.
1367*4a3b33f8SAndrii Nakryiko  * Returns:
1368*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1369*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1370*4a3b33f8SAndrii Nakryiko  */
1371*4a3b33f8SAndrii Nakryiko int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding)
1372*4a3b33f8SAndrii Nakryiko {
1373*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1374*4a3b33f8SAndrii Nakryiko 	int sz, err, name_off;
1375*4a3b33f8SAndrii Nakryiko 
1376*4a3b33f8SAndrii Nakryiko 	/* non-empty name */
1377*4a3b33f8SAndrii Nakryiko 	if (!name || !name[0])
1378*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1379*4a3b33f8SAndrii Nakryiko 	/* byte_sz must be power of 2 */
1380*4a3b33f8SAndrii Nakryiko 	if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16)
1381*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1382*4a3b33f8SAndrii Nakryiko 	if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL))
1383*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1384*4a3b33f8SAndrii Nakryiko 
1385*4a3b33f8SAndrii Nakryiko 	/* deconstruct BTF, if necessary, and invalidate raw_data */
1386*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1387*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1388*4a3b33f8SAndrii Nakryiko 
1389*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type) + sizeof(int);
1390*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
1391*4a3b33f8SAndrii Nakryiko 	if (!t)
1392*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1393*4a3b33f8SAndrii Nakryiko 
1394*4a3b33f8SAndrii Nakryiko 	/* if something goes wrong later, we might end up with an extra string,
1395*4a3b33f8SAndrii Nakryiko 	 * but that shouldn't be a problem, because BTF can't be constructed
1396*4a3b33f8SAndrii Nakryiko 	 * completely anyway and will most probably be just discarded
1397*4a3b33f8SAndrii Nakryiko 	 */
1398*4a3b33f8SAndrii Nakryiko 	name_off = btf__add_str(btf, name);
1399*4a3b33f8SAndrii Nakryiko 	if (name_off < 0)
1400*4a3b33f8SAndrii Nakryiko 		return name_off;
1401*4a3b33f8SAndrii Nakryiko 
1402*4a3b33f8SAndrii Nakryiko 	t->name_off = name_off;
1403*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(BTF_KIND_INT, 0, 0);
1404*4a3b33f8SAndrii Nakryiko 	t->size = byte_sz;
1405*4a3b33f8SAndrii Nakryiko 	/* set INT info, we don't allow setting legacy bit offset/size */
1406*4a3b33f8SAndrii Nakryiko 	*(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8);
1407*4a3b33f8SAndrii Nakryiko 
1408*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
1409*4a3b33f8SAndrii Nakryiko 	if (err)
1410*4a3b33f8SAndrii Nakryiko 		return err;
1411*4a3b33f8SAndrii Nakryiko 
1412*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1413*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1414*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
1415*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
1416*4a3b33f8SAndrii Nakryiko }
1417*4a3b33f8SAndrii Nakryiko 
1418*4a3b33f8SAndrii Nakryiko /* it's completely legal to append BTF types with type IDs pointing forward to
1419*4a3b33f8SAndrii Nakryiko  * types that haven't been appended yet, so we only make sure that id looks
1420*4a3b33f8SAndrii Nakryiko  * sane, we can't guarantee that ID will always be valid
1421*4a3b33f8SAndrii Nakryiko  */
1422*4a3b33f8SAndrii Nakryiko static int validate_type_id(int id)
1423*4a3b33f8SAndrii Nakryiko {
1424*4a3b33f8SAndrii Nakryiko 	if (id < 0 || id > BTF_MAX_NR_TYPES)
1425*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1426*4a3b33f8SAndrii Nakryiko 	return 0;
1427*4a3b33f8SAndrii Nakryiko }
1428*4a3b33f8SAndrii Nakryiko 
1429*4a3b33f8SAndrii Nakryiko /* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */
1430*4a3b33f8SAndrii Nakryiko static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id)
1431*4a3b33f8SAndrii Nakryiko {
1432*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1433*4a3b33f8SAndrii Nakryiko 	int sz, name_off = 0, err;
1434*4a3b33f8SAndrii Nakryiko 
1435*4a3b33f8SAndrii Nakryiko 	if (validate_type_id(ref_type_id))
1436*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1437*4a3b33f8SAndrii Nakryiko 
1438*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1439*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1440*4a3b33f8SAndrii Nakryiko 
1441*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type);
1442*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
1443*4a3b33f8SAndrii Nakryiko 	if (!t)
1444*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1445*4a3b33f8SAndrii Nakryiko 
1446*4a3b33f8SAndrii Nakryiko 	if (name && name[0]) {
1447*4a3b33f8SAndrii Nakryiko 		name_off = btf__add_str(btf, name);
1448*4a3b33f8SAndrii Nakryiko 		if (name_off < 0)
1449*4a3b33f8SAndrii Nakryiko 			return name_off;
1450*4a3b33f8SAndrii Nakryiko 	}
1451*4a3b33f8SAndrii Nakryiko 
1452*4a3b33f8SAndrii Nakryiko 	t->name_off = name_off;
1453*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(kind, 0, 0);
1454*4a3b33f8SAndrii Nakryiko 	t->type = ref_type_id;
1455*4a3b33f8SAndrii Nakryiko 
1456*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
1457*4a3b33f8SAndrii Nakryiko 	if (err)
1458*4a3b33f8SAndrii Nakryiko 		return err;
1459*4a3b33f8SAndrii Nakryiko 
1460*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1461*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1462*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
1463*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
1464*4a3b33f8SAndrii Nakryiko }
1465*4a3b33f8SAndrii Nakryiko 
1466*4a3b33f8SAndrii Nakryiko /*
1467*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_PTR type with:
1468*4a3b33f8SAndrii Nakryiko  *   - *ref_type_id* - referenced type ID, it might not exist yet;
1469*4a3b33f8SAndrii Nakryiko  * Returns:
1470*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1471*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1472*4a3b33f8SAndrii Nakryiko  */
1473*4a3b33f8SAndrii Nakryiko int btf__add_ptr(struct btf *btf, int ref_type_id)
1474*4a3b33f8SAndrii Nakryiko {
1475*4a3b33f8SAndrii Nakryiko 	return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id);
1476*4a3b33f8SAndrii Nakryiko }
1477*4a3b33f8SAndrii Nakryiko 
1478*4a3b33f8SAndrii Nakryiko /*
1479*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_ARRAY type with:
1480*4a3b33f8SAndrii Nakryiko  *   - *index_type_id* - type ID of the type describing array index;
1481*4a3b33f8SAndrii Nakryiko  *   - *elem_type_id* - type ID of the type describing array element;
1482*4a3b33f8SAndrii Nakryiko  *   - *nr_elems* - the size of the array;
1483*4a3b33f8SAndrii Nakryiko  * Returns:
1484*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1485*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1486*4a3b33f8SAndrii Nakryiko  */
1487*4a3b33f8SAndrii Nakryiko int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems)
1488*4a3b33f8SAndrii Nakryiko {
1489*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1490*4a3b33f8SAndrii Nakryiko 	struct btf_array *a;
1491*4a3b33f8SAndrii Nakryiko 	int sz, err;
1492*4a3b33f8SAndrii Nakryiko 
1493*4a3b33f8SAndrii Nakryiko 	if (validate_type_id(index_type_id) || validate_type_id(elem_type_id))
1494*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1495*4a3b33f8SAndrii Nakryiko 
1496*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1497*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1498*4a3b33f8SAndrii Nakryiko 
1499*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type) + sizeof(struct btf_array);
1500*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
1501*4a3b33f8SAndrii Nakryiko 	if (!t)
1502*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1503*4a3b33f8SAndrii Nakryiko 
1504*4a3b33f8SAndrii Nakryiko 	t->name_off = 0;
1505*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0);
1506*4a3b33f8SAndrii Nakryiko 	t->size = 0;
1507*4a3b33f8SAndrii Nakryiko 
1508*4a3b33f8SAndrii Nakryiko 	a = btf_array(t);
1509*4a3b33f8SAndrii Nakryiko 	a->type = elem_type_id;
1510*4a3b33f8SAndrii Nakryiko 	a->index_type = index_type_id;
1511*4a3b33f8SAndrii Nakryiko 	a->nelems = nr_elems;
1512*4a3b33f8SAndrii Nakryiko 
1513*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
1514*4a3b33f8SAndrii Nakryiko 	if (err)
1515*4a3b33f8SAndrii Nakryiko 		return err;
1516*4a3b33f8SAndrii Nakryiko 
1517*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1518*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1519*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
1520*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
1521*4a3b33f8SAndrii Nakryiko }
1522*4a3b33f8SAndrii Nakryiko 
1523*4a3b33f8SAndrii Nakryiko /* generic STRUCT/UNION append function */
1524*4a3b33f8SAndrii Nakryiko static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz)
1525*4a3b33f8SAndrii Nakryiko {
1526*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1527*4a3b33f8SAndrii Nakryiko 	int sz, err, name_off = 0;
1528*4a3b33f8SAndrii Nakryiko 
1529*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1530*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1531*4a3b33f8SAndrii Nakryiko 
1532*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type);
1533*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
1534*4a3b33f8SAndrii Nakryiko 	if (!t)
1535*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1536*4a3b33f8SAndrii Nakryiko 
1537*4a3b33f8SAndrii Nakryiko 	if (name && name[0]) {
1538*4a3b33f8SAndrii Nakryiko 		name_off = btf__add_str(btf, name);
1539*4a3b33f8SAndrii Nakryiko 		if (name_off < 0)
1540*4a3b33f8SAndrii Nakryiko 			return name_off;
1541*4a3b33f8SAndrii Nakryiko 	}
1542*4a3b33f8SAndrii Nakryiko 
1543*4a3b33f8SAndrii Nakryiko 	/* start out with vlen=0 and no kflag; this will be adjusted when
1544*4a3b33f8SAndrii Nakryiko 	 * adding each member
1545*4a3b33f8SAndrii Nakryiko 	 */
1546*4a3b33f8SAndrii Nakryiko 	t->name_off = name_off;
1547*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(kind, 0, 0);
1548*4a3b33f8SAndrii Nakryiko 	t->size = bytes_sz;
1549*4a3b33f8SAndrii Nakryiko 
1550*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
1551*4a3b33f8SAndrii Nakryiko 	if (err)
1552*4a3b33f8SAndrii Nakryiko 		return err;
1553*4a3b33f8SAndrii Nakryiko 
1554*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1555*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1556*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
1557*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
1558*4a3b33f8SAndrii Nakryiko }
1559*4a3b33f8SAndrii Nakryiko 
1560*4a3b33f8SAndrii Nakryiko /*
1561*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_STRUCT type with:
1562*4a3b33f8SAndrii Nakryiko  *   - *name* - name of the struct, can be NULL or empty for anonymous structs;
1563*4a3b33f8SAndrii Nakryiko  *   - *byte_sz* - size of the struct, in bytes;
1564*4a3b33f8SAndrii Nakryiko  *
1565*4a3b33f8SAndrii Nakryiko  * Struct initially has no fields in it. Fields can be added by
1566*4a3b33f8SAndrii Nakryiko  * btf__add_field() right after btf__add_struct() succeeds.
1567*4a3b33f8SAndrii Nakryiko  *
1568*4a3b33f8SAndrii Nakryiko  * Returns:
1569*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1570*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1571*4a3b33f8SAndrii Nakryiko  */
1572*4a3b33f8SAndrii Nakryiko int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz)
1573*4a3b33f8SAndrii Nakryiko {
1574*4a3b33f8SAndrii Nakryiko 	return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz);
1575*4a3b33f8SAndrii Nakryiko }
1576*4a3b33f8SAndrii Nakryiko 
1577*4a3b33f8SAndrii Nakryiko /*
1578*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_UNION type with:
1579*4a3b33f8SAndrii Nakryiko  *   - *name* - name of the union, can be NULL or empty for anonymous union;
1580*4a3b33f8SAndrii Nakryiko  *   - *byte_sz* - size of the union, in bytes;
1581*4a3b33f8SAndrii Nakryiko  *
1582*4a3b33f8SAndrii Nakryiko  * Union initially has no fields in it. Fields can be added by
1583*4a3b33f8SAndrii Nakryiko  * btf__add_field() right after btf__add_union() succeeds. All fields
1584*4a3b33f8SAndrii Nakryiko  * should have *bit_offset* of 0.
1585*4a3b33f8SAndrii Nakryiko  *
1586*4a3b33f8SAndrii Nakryiko  * Returns:
1587*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1588*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1589*4a3b33f8SAndrii Nakryiko  */
1590*4a3b33f8SAndrii Nakryiko int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz)
1591*4a3b33f8SAndrii Nakryiko {
1592*4a3b33f8SAndrii Nakryiko 	return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz);
1593*4a3b33f8SAndrii Nakryiko }
1594*4a3b33f8SAndrii Nakryiko 
1595*4a3b33f8SAndrii Nakryiko /*
1596*4a3b33f8SAndrii Nakryiko  * Append new field for the current STRUCT/UNION type with:
1597*4a3b33f8SAndrii Nakryiko  *   - *name* - name of the field, can be NULL or empty for anonymous field;
1598*4a3b33f8SAndrii Nakryiko  *   - *type_id* - type ID for the type describing field type;
1599*4a3b33f8SAndrii Nakryiko  *   - *bit_offset* - bit offset of the start of the field within struct/union;
1600*4a3b33f8SAndrii Nakryiko  *   - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields;
1601*4a3b33f8SAndrii Nakryiko  * Returns:
1602*4a3b33f8SAndrii Nakryiko  *   -  0, on success;
1603*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1604*4a3b33f8SAndrii Nakryiko  */
1605*4a3b33f8SAndrii Nakryiko int btf__add_field(struct btf *btf, const char *name, int type_id,
1606*4a3b33f8SAndrii Nakryiko 		   __u32 bit_offset, __u32 bit_size)
1607*4a3b33f8SAndrii Nakryiko {
1608*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1609*4a3b33f8SAndrii Nakryiko 	struct btf_member *m;
1610*4a3b33f8SAndrii Nakryiko 	bool is_bitfield;
1611*4a3b33f8SAndrii Nakryiko 	int sz, name_off = 0;
1612*4a3b33f8SAndrii Nakryiko 
1613*4a3b33f8SAndrii Nakryiko 	/* last type should be union/struct */
1614*4a3b33f8SAndrii Nakryiko 	if (btf->nr_types == 0)
1615*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1616*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
1617*4a3b33f8SAndrii Nakryiko 	if (!btf_is_composite(t))
1618*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1619*4a3b33f8SAndrii Nakryiko 
1620*4a3b33f8SAndrii Nakryiko 	if (validate_type_id(type_id))
1621*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1622*4a3b33f8SAndrii Nakryiko 	/* best-effort bit field offset/size enforcement */
1623*4a3b33f8SAndrii Nakryiko 	is_bitfield = bit_size || (bit_offset % 8 != 0);
1624*4a3b33f8SAndrii Nakryiko 	if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff))
1625*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1626*4a3b33f8SAndrii Nakryiko 
1627*4a3b33f8SAndrii Nakryiko 	/* only offset 0 is allowed for unions */
1628*4a3b33f8SAndrii Nakryiko 	if (btf_is_union(t) && bit_offset)
1629*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1630*4a3b33f8SAndrii Nakryiko 
1631*4a3b33f8SAndrii Nakryiko 	/* decompose and invalidate raw data */
1632*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1633*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1634*4a3b33f8SAndrii Nakryiko 
1635*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_member);
1636*4a3b33f8SAndrii Nakryiko 	m = btf_add_type_mem(btf, sz);
1637*4a3b33f8SAndrii Nakryiko 	if (!m)
1638*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1639*4a3b33f8SAndrii Nakryiko 
1640*4a3b33f8SAndrii Nakryiko 	if (name && name[0]) {
1641*4a3b33f8SAndrii Nakryiko 		name_off = btf__add_str(btf, name);
1642*4a3b33f8SAndrii Nakryiko 		if (name_off < 0)
1643*4a3b33f8SAndrii Nakryiko 			return name_off;
1644*4a3b33f8SAndrii Nakryiko 	}
1645*4a3b33f8SAndrii Nakryiko 
1646*4a3b33f8SAndrii Nakryiko 	m->name_off = name_off;
1647*4a3b33f8SAndrii Nakryiko 	m->type = type_id;
1648*4a3b33f8SAndrii Nakryiko 	m->offset = bit_offset | (bit_size << 24);
1649*4a3b33f8SAndrii Nakryiko 
1650*4a3b33f8SAndrii Nakryiko 	/* btf_add_type_mem can invalidate t pointer */
1651*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
1652*4a3b33f8SAndrii Nakryiko 	/* update parent type's vlen and kflag */
1653*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t));
1654*4a3b33f8SAndrii Nakryiko 
1655*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1656*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1657*4a3b33f8SAndrii Nakryiko 	return 0;
1658*4a3b33f8SAndrii Nakryiko }
1659*4a3b33f8SAndrii Nakryiko 
1660*4a3b33f8SAndrii Nakryiko /*
1661*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_ENUM type with:
1662*4a3b33f8SAndrii Nakryiko  *   - *name* - name of the enum, can be NULL or empty for anonymous enums;
1663*4a3b33f8SAndrii Nakryiko  *   - *byte_sz* - size of the enum, in bytes.
1664*4a3b33f8SAndrii Nakryiko  *
1665*4a3b33f8SAndrii Nakryiko  * Enum initially has no enum values in it (and corresponds to enum forward
1666*4a3b33f8SAndrii Nakryiko  * declaration). Enumerator values can be added by btf__add_enum_value()
1667*4a3b33f8SAndrii Nakryiko  * immediately after btf__add_enum() succeeds.
1668*4a3b33f8SAndrii Nakryiko  *
1669*4a3b33f8SAndrii Nakryiko  * Returns:
1670*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1671*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1672*4a3b33f8SAndrii Nakryiko  */
1673*4a3b33f8SAndrii Nakryiko int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz)
1674*4a3b33f8SAndrii Nakryiko {
1675*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1676*4a3b33f8SAndrii Nakryiko 	int sz, err, name_off = 0;
1677*4a3b33f8SAndrii Nakryiko 
1678*4a3b33f8SAndrii Nakryiko 	/* byte_sz must be power of 2 */
1679*4a3b33f8SAndrii Nakryiko 	if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8)
1680*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1681*4a3b33f8SAndrii Nakryiko 
1682*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1683*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1684*4a3b33f8SAndrii Nakryiko 
1685*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type);
1686*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
1687*4a3b33f8SAndrii Nakryiko 	if (!t)
1688*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1689*4a3b33f8SAndrii Nakryiko 
1690*4a3b33f8SAndrii Nakryiko 	if (name && name[0]) {
1691*4a3b33f8SAndrii Nakryiko 		name_off = btf__add_str(btf, name);
1692*4a3b33f8SAndrii Nakryiko 		if (name_off < 0)
1693*4a3b33f8SAndrii Nakryiko 			return name_off;
1694*4a3b33f8SAndrii Nakryiko 	}
1695*4a3b33f8SAndrii Nakryiko 
1696*4a3b33f8SAndrii Nakryiko 	/* start out with vlen=0; it will be adjusted when adding enum values */
1697*4a3b33f8SAndrii Nakryiko 	t->name_off = name_off;
1698*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(BTF_KIND_ENUM, 0, 0);
1699*4a3b33f8SAndrii Nakryiko 	t->size = byte_sz;
1700*4a3b33f8SAndrii Nakryiko 
1701*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
1702*4a3b33f8SAndrii Nakryiko 	if (err)
1703*4a3b33f8SAndrii Nakryiko 		return err;
1704*4a3b33f8SAndrii Nakryiko 
1705*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1706*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1707*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
1708*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
1709*4a3b33f8SAndrii Nakryiko }
1710*4a3b33f8SAndrii Nakryiko 
1711*4a3b33f8SAndrii Nakryiko /*
1712*4a3b33f8SAndrii Nakryiko  * Append new enum value for the current ENUM type with:
1713*4a3b33f8SAndrii Nakryiko  *   - *name* - name of the enumerator value, can't be NULL or empty;
1714*4a3b33f8SAndrii Nakryiko  *   - *value* - integer value corresponding to enum value *name*;
1715*4a3b33f8SAndrii Nakryiko  * Returns:
1716*4a3b33f8SAndrii Nakryiko  *   -  0, on success;
1717*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1718*4a3b33f8SAndrii Nakryiko  */
1719*4a3b33f8SAndrii Nakryiko int btf__add_enum_value(struct btf *btf, const char *name, __s64 value)
1720*4a3b33f8SAndrii Nakryiko {
1721*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1722*4a3b33f8SAndrii Nakryiko 	struct btf_enum *v;
1723*4a3b33f8SAndrii Nakryiko 	int sz, name_off;
1724*4a3b33f8SAndrii Nakryiko 
1725*4a3b33f8SAndrii Nakryiko 	/* last type should be BTF_KIND_ENUM */
1726*4a3b33f8SAndrii Nakryiko 	if (btf->nr_types == 0)
1727*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1728*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
1729*4a3b33f8SAndrii Nakryiko 	if (!btf_is_enum(t))
1730*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1731*4a3b33f8SAndrii Nakryiko 
1732*4a3b33f8SAndrii Nakryiko 	/* non-empty name */
1733*4a3b33f8SAndrii Nakryiko 	if (!name || !name[0])
1734*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1735*4a3b33f8SAndrii Nakryiko 	if (value < INT_MIN || value > UINT_MAX)
1736*4a3b33f8SAndrii Nakryiko 		return -E2BIG;
1737*4a3b33f8SAndrii Nakryiko 
1738*4a3b33f8SAndrii Nakryiko 	/* decompose and invalidate raw data */
1739*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1740*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1741*4a3b33f8SAndrii Nakryiko 
1742*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_enum);
1743*4a3b33f8SAndrii Nakryiko 	v = btf_add_type_mem(btf, sz);
1744*4a3b33f8SAndrii Nakryiko 	if (!v)
1745*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1746*4a3b33f8SAndrii Nakryiko 
1747*4a3b33f8SAndrii Nakryiko 	name_off = btf__add_str(btf, name);
1748*4a3b33f8SAndrii Nakryiko 	if (name_off < 0)
1749*4a3b33f8SAndrii Nakryiko 		return name_off;
1750*4a3b33f8SAndrii Nakryiko 
1751*4a3b33f8SAndrii Nakryiko 	v->name_off = name_off;
1752*4a3b33f8SAndrii Nakryiko 	v->val = value;
1753*4a3b33f8SAndrii Nakryiko 
1754*4a3b33f8SAndrii Nakryiko 	/* update parent type's vlen */
1755*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
1756*4a3b33f8SAndrii Nakryiko 	btf_type_inc_vlen(t);
1757*4a3b33f8SAndrii Nakryiko 
1758*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1759*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1760*4a3b33f8SAndrii Nakryiko 	return 0;
1761*4a3b33f8SAndrii Nakryiko }
1762*4a3b33f8SAndrii Nakryiko 
1763*4a3b33f8SAndrii Nakryiko /*
1764*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_FWD type with:
1765*4a3b33f8SAndrii Nakryiko  *   - *name*, non-empty/non-NULL name;
1766*4a3b33f8SAndrii Nakryiko  *   - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT,
1767*4a3b33f8SAndrii Nakryiko  *     BTF_FWD_UNION, or BTF_FWD_ENUM;
1768*4a3b33f8SAndrii Nakryiko  * Returns:
1769*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1770*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1771*4a3b33f8SAndrii Nakryiko  */
1772*4a3b33f8SAndrii Nakryiko int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind)
1773*4a3b33f8SAndrii Nakryiko {
1774*4a3b33f8SAndrii Nakryiko 	if (!name || !name[0])
1775*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1776*4a3b33f8SAndrii Nakryiko 
1777*4a3b33f8SAndrii Nakryiko 	switch (fwd_kind) {
1778*4a3b33f8SAndrii Nakryiko 	case BTF_FWD_STRUCT:
1779*4a3b33f8SAndrii Nakryiko 	case BTF_FWD_UNION: {
1780*4a3b33f8SAndrii Nakryiko 		struct btf_type *t;
1781*4a3b33f8SAndrii Nakryiko 		int id;
1782*4a3b33f8SAndrii Nakryiko 
1783*4a3b33f8SAndrii Nakryiko 		id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0);
1784*4a3b33f8SAndrii Nakryiko 		if (id <= 0)
1785*4a3b33f8SAndrii Nakryiko 			return id;
1786*4a3b33f8SAndrii Nakryiko 		t = btf_type_by_id(btf, id);
1787*4a3b33f8SAndrii Nakryiko 		t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION);
1788*4a3b33f8SAndrii Nakryiko 		return id;
1789*4a3b33f8SAndrii Nakryiko 	}
1790*4a3b33f8SAndrii Nakryiko 	case BTF_FWD_ENUM:
1791*4a3b33f8SAndrii Nakryiko 		/* enum forward in BTF currently is just an enum with no enum
1792*4a3b33f8SAndrii Nakryiko 		 * values; we also assume a standard 4-byte size for it
1793*4a3b33f8SAndrii Nakryiko 		 */
1794*4a3b33f8SAndrii Nakryiko 		return btf__add_enum(btf, name, sizeof(int));
1795*4a3b33f8SAndrii Nakryiko 	default:
1796*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1797*4a3b33f8SAndrii Nakryiko 	}
1798*4a3b33f8SAndrii Nakryiko }
1799*4a3b33f8SAndrii Nakryiko 
1800*4a3b33f8SAndrii Nakryiko /*
1801*4a3b33f8SAndrii Nakryiko  * Append new BTF_KING_TYPEDEF type with:
1802*4a3b33f8SAndrii Nakryiko  *   - *name*, non-empty/non-NULL name;
1803*4a3b33f8SAndrii Nakryiko  *   - *ref_type_id* - referenced type ID, it might not exist yet;
1804*4a3b33f8SAndrii Nakryiko  * Returns:
1805*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1806*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1807*4a3b33f8SAndrii Nakryiko  */
1808*4a3b33f8SAndrii Nakryiko int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id)
1809*4a3b33f8SAndrii Nakryiko {
1810*4a3b33f8SAndrii Nakryiko 	if (!name || !name[0])
1811*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1812*4a3b33f8SAndrii Nakryiko 
1813*4a3b33f8SAndrii Nakryiko 	return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id);
1814*4a3b33f8SAndrii Nakryiko }
1815*4a3b33f8SAndrii Nakryiko 
1816*4a3b33f8SAndrii Nakryiko /*
1817*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_VOLATILE type with:
1818*4a3b33f8SAndrii Nakryiko  *   - *ref_type_id* - referenced type ID, it might not exist yet;
1819*4a3b33f8SAndrii Nakryiko  * Returns:
1820*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1821*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1822*4a3b33f8SAndrii Nakryiko  */
1823*4a3b33f8SAndrii Nakryiko int btf__add_volatile(struct btf *btf, int ref_type_id)
1824*4a3b33f8SAndrii Nakryiko {
1825*4a3b33f8SAndrii Nakryiko 	return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id);
1826*4a3b33f8SAndrii Nakryiko }
1827*4a3b33f8SAndrii Nakryiko 
1828*4a3b33f8SAndrii Nakryiko /*
1829*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_CONST type with:
1830*4a3b33f8SAndrii Nakryiko  *   - *ref_type_id* - referenced type ID, it might not exist yet;
1831*4a3b33f8SAndrii Nakryiko  * Returns:
1832*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1833*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1834*4a3b33f8SAndrii Nakryiko  */
1835*4a3b33f8SAndrii Nakryiko int btf__add_const(struct btf *btf, int ref_type_id)
1836*4a3b33f8SAndrii Nakryiko {
1837*4a3b33f8SAndrii Nakryiko 	return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id);
1838*4a3b33f8SAndrii Nakryiko }
1839*4a3b33f8SAndrii Nakryiko 
1840*4a3b33f8SAndrii Nakryiko /*
1841*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_RESTRICT type with:
1842*4a3b33f8SAndrii Nakryiko  *   - *ref_type_id* - referenced type ID, it might not exist yet;
1843*4a3b33f8SAndrii Nakryiko  * Returns:
1844*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1845*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1846*4a3b33f8SAndrii Nakryiko  */
1847*4a3b33f8SAndrii Nakryiko int btf__add_restrict(struct btf *btf, int ref_type_id)
1848*4a3b33f8SAndrii Nakryiko {
1849*4a3b33f8SAndrii Nakryiko 	return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id);
1850*4a3b33f8SAndrii Nakryiko }
1851*4a3b33f8SAndrii Nakryiko 
1852*4a3b33f8SAndrii Nakryiko /*
1853*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_FUNC type with:
1854*4a3b33f8SAndrii Nakryiko  *   - *name*, non-empty/non-NULL name;
1855*4a3b33f8SAndrii Nakryiko  *   - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet;
1856*4a3b33f8SAndrii Nakryiko  * Returns:
1857*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1858*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1859*4a3b33f8SAndrii Nakryiko  */
1860*4a3b33f8SAndrii Nakryiko int btf__add_func(struct btf *btf, const char *name,
1861*4a3b33f8SAndrii Nakryiko 		  enum btf_func_linkage linkage, int proto_type_id)
1862*4a3b33f8SAndrii Nakryiko {
1863*4a3b33f8SAndrii Nakryiko 	int id;
1864*4a3b33f8SAndrii Nakryiko 
1865*4a3b33f8SAndrii Nakryiko 	if (!name || !name[0])
1866*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1867*4a3b33f8SAndrii Nakryiko 	if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL &&
1868*4a3b33f8SAndrii Nakryiko 	    linkage != BTF_FUNC_EXTERN)
1869*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1870*4a3b33f8SAndrii Nakryiko 
1871*4a3b33f8SAndrii Nakryiko 	id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id);
1872*4a3b33f8SAndrii Nakryiko 	if (id > 0) {
1873*4a3b33f8SAndrii Nakryiko 		struct btf_type *t = btf_type_by_id(btf, id);
1874*4a3b33f8SAndrii Nakryiko 
1875*4a3b33f8SAndrii Nakryiko 		t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0);
1876*4a3b33f8SAndrii Nakryiko 	}
1877*4a3b33f8SAndrii Nakryiko 	return id;
1878*4a3b33f8SAndrii Nakryiko }
1879*4a3b33f8SAndrii Nakryiko 
1880*4a3b33f8SAndrii Nakryiko /*
1881*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_FUNC_PROTO with:
1882*4a3b33f8SAndrii Nakryiko  *   - *ret_type_id* - type ID for return result of a function.
1883*4a3b33f8SAndrii Nakryiko  *
1884*4a3b33f8SAndrii Nakryiko  * Function prototype initially has no arguments, but they can be added by
1885*4a3b33f8SAndrii Nakryiko  * btf__add_func_param() one by one, immediately after
1886*4a3b33f8SAndrii Nakryiko  * btf__add_func_proto() succeeded.
1887*4a3b33f8SAndrii Nakryiko  *
1888*4a3b33f8SAndrii Nakryiko  * Returns:
1889*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1890*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1891*4a3b33f8SAndrii Nakryiko  */
1892*4a3b33f8SAndrii Nakryiko int btf__add_func_proto(struct btf *btf, int ret_type_id)
1893*4a3b33f8SAndrii Nakryiko {
1894*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1895*4a3b33f8SAndrii Nakryiko 	int sz, err;
1896*4a3b33f8SAndrii Nakryiko 
1897*4a3b33f8SAndrii Nakryiko 	if (validate_type_id(ret_type_id))
1898*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1899*4a3b33f8SAndrii Nakryiko 
1900*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1901*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1902*4a3b33f8SAndrii Nakryiko 
1903*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type);
1904*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
1905*4a3b33f8SAndrii Nakryiko 	if (!t)
1906*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1907*4a3b33f8SAndrii Nakryiko 
1908*4a3b33f8SAndrii Nakryiko 	/* start out with vlen=0; this will be adjusted when adding enum
1909*4a3b33f8SAndrii Nakryiko 	 * values, if necessary
1910*4a3b33f8SAndrii Nakryiko 	 */
1911*4a3b33f8SAndrii Nakryiko 	t->name_off = 0;
1912*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0);
1913*4a3b33f8SAndrii Nakryiko 	t->type = ret_type_id;
1914*4a3b33f8SAndrii Nakryiko 
1915*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
1916*4a3b33f8SAndrii Nakryiko 	if (err)
1917*4a3b33f8SAndrii Nakryiko 		return err;
1918*4a3b33f8SAndrii Nakryiko 
1919*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1920*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1921*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
1922*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
1923*4a3b33f8SAndrii Nakryiko }
1924*4a3b33f8SAndrii Nakryiko 
1925*4a3b33f8SAndrii Nakryiko /*
1926*4a3b33f8SAndrii Nakryiko  * Append new function parameter for current FUNC_PROTO type with:
1927*4a3b33f8SAndrii Nakryiko  *   - *name* - parameter name, can be NULL or empty;
1928*4a3b33f8SAndrii Nakryiko  *   - *type_id* - type ID describing the type of the parameter.
1929*4a3b33f8SAndrii Nakryiko  * Returns:
1930*4a3b33f8SAndrii Nakryiko  *   -  0, on success;
1931*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1932*4a3b33f8SAndrii Nakryiko  */
1933*4a3b33f8SAndrii Nakryiko int btf__add_func_param(struct btf *btf, const char *name, int type_id)
1934*4a3b33f8SAndrii Nakryiko {
1935*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1936*4a3b33f8SAndrii Nakryiko 	struct btf_param *p;
1937*4a3b33f8SAndrii Nakryiko 	int sz, name_off = 0;
1938*4a3b33f8SAndrii Nakryiko 
1939*4a3b33f8SAndrii Nakryiko 	if (validate_type_id(type_id))
1940*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1941*4a3b33f8SAndrii Nakryiko 
1942*4a3b33f8SAndrii Nakryiko 	/* last type should be BTF_KIND_FUNC_PROTO */
1943*4a3b33f8SAndrii Nakryiko 	if (btf->nr_types == 0)
1944*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1945*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
1946*4a3b33f8SAndrii Nakryiko 	if (!btf_is_func_proto(t))
1947*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1948*4a3b33f8SAndrii Nakryiko 
1949*4a3b33f8SAndrii Nakryiko 	/* decompose and invalidate raw data */
1950*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
1951*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1952*4a3b33f8SAndrii Nakryiko 
1953*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_param);
1954*4a3b33f8SAndrii Nakryiko 	p = btf_add_type_mem(btf, sz);
1955*4a3b33f8SAndrii Nakryiko 	if (!p)
1956*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
1957*4a3b33f8SAndrii Nakryiko 
1958*4a3b33f8SAndrii Nakryiko 	if (name && name[0]) {
1959*4a3b33f8SAndrii Nakryiko 		name_off = btf__add_str(btf, name);
1960*4a3b33f8SAndrii Nakryiko 		if (name_off < 0)
1961*4a3b33f8SAndrii Nakryiko 			return name_off;
1962*4a3b33f8SAndrii Nakryiko 	}
1963*4a3b33f8SAndrii Nakryiko 
1964*4a3b33f8SAndrii Nakryiko 	p->name_off = name_off;
1965*4a3b33f8SAndrii Nakryiko 	p->type = type_id;
1966*4a3b33f8SAndrii Nakryiko 
1967*4a3b33f8SAndrii Nakryiko 	/* update parent type's vlen */
1968*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
1969*4a3b33f8SAndrii Nakryiko 	btf_type_inc_vlen(t);
1970*4a3b33f8SAndrii Nakryiko 
1971*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
1972*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
1973*4a3b33f8SAndrii Nakryiko 	return 0;
1974*4a3b33f8SAndrii Nakryiko }
1975*4a3b33f8SAndrii Nakryiko 
1976*4a3b33f8SAndrii Nakryiko /*
1977*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_VAR type with:
1978*4a3b33f8SAndrii Nakryiko  *   - *name* - non-empty/non-NULL name;
1979*4a3b33f8SAndrii Nakryiko  *   - *linkage* - variable linkage, one of BTF_VAR_STATIC,
1980*4a3b33f8SAndrii Nakryiko  *     BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN;
1981*4a3b33f8SAndrii Nakryiko  *   - *type_id* - type ID of the type describing the type of the variable.
1982*4a3b33f8SAndrii Nakryiko  * Returns:
1983*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
1984*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
1985*4a3b33f8SAndrii Nakryiko  */
1986*4a3b33f8SAndrii Nakryiko int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id)
1987*4a3b33f8SAndrii Nakryiko {
1988*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
1989*4a3b33f8SAndrii Nakryiko 	struct btf_var *v;
1990*4a3b33f8SAndrii Nakryiko 	int sz, err, name_off;
1991*4a3b33f8SAndrii Nakryiko 
1992*4a3b33f8SAndrii Nakryiko 	/* non-empty name */
1993*4a3b33f8SAndrii Nakryiko 	if (!name || !name[0])
1994*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1995*4a3b33f8SAndrii Nakryiko 	if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED &&
1996*4a3b33f8SAndrii Nakryiko 	    linkage != BTF_VAR_GLOBAL_EXTERN)
1997*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
1998*4a3b33f8SAndrii Nakryiko 	if (validate_type_id(type_id))
1999*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
2000*4a3b33f8SAndrii Nakryiko 
2001*4a3b33f8SAndrii Nakryiko 	/* deconstruct BTF, if necessary, and invalidate raw_data */
2002*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
2003*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
2004*4a3b33f8SAndrii Nakryiko 
2005*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type) + sizeof(struct btf_var);
2006*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
2007*4a3b33f8SAndrii Nakryiko 	if (!t)
2008*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
2009*4a3b33f8SAndrii Nakryiko 
2010*4a3b33f8SAndrii Nakryiko 	name_off = btf__add_str(btf, name);
2011*4a3b33f8SAndrii Nakryiko 	if (name_off < 0)
2012*4a3b33f8SAndrii Nakryiko 		return name_off;
2013*4a3b33f8SAndrii Nakryiko 
2014*4a3b33f8SAndrii Nakryiko 	t->name_off = name_off;
2015*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(BTF_KIND_VAR, 0, 0);
2016*4a3b33f8SAndrii Nakryiko 	t->type = type_id;
2017*4a3b33f8SAndrii Nakryiko 
2018*4a3b33f8SAndrii Nakryiko 	v = btf_var(t);
2019*4a3b33f8SAndrii Nakryiko 	v->linkage = linkage;
2020*4a3b33f8SAndrii Nakryiko 
2021*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
2022*4a3b33f8SAndrii Nakryiko 	if (err)
2023*4a3b33f8SAndrii Nakryiko 		return err;
2024*4a3b33f8SAndrii Nakryiko 
2025*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
2026*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
2027*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
2028*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
2029*4a3b33f8SAndrii Nakryiko }
2030*4a3b33f8SAndrii Nakryiko 
2031*4a3b33f8SAndrii Nakryiko /*
2032*4a3b33f8SAndrii Nakryiko  * Append new BTF_KIND_DATASEC type with:
2033*4a3b33f8SAndrii Nakryiko  *   - *name* - non-empty/non-NULL name;
2034*4a3b33f8SAndrii Nakryiko  *   - *byte_sz* - data section size, in bytes.
2035*4a3b33f8SAndrii Nakryiko  *
2036*4a3b33f8SAndrii Nakryiko  * Data section is initially empty. Variables info can be added with
2037*4a3b33f8SAndrii Nakryiko  * btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds.
2038*4a3b33f8SAndrii Nakryiko  *
2039*4a3b33f8SAndrii Nakryiko  * Returns:
2040*4a3b33f8SAndrii Nakryiko  *   - >0, type ID of newly added BTF type;
2041*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
2042*4a3b33f8SAndrii Nakryiko  */
2043*4a3b33f8SAndrii Nakryiko int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz)
2044*4a3b33f8SAndrii Nakryiko {
2045*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
2046*4a3b33f8SAndrii Nakryiko 	int sz, err, name_off;
2047*4a3b33f8SAndrii Nakryiko 
2048*4a3b33f8SAndrii Nakryiko 	/* non-empty name */
2049*4a3b33f8SAndrii Nakryiko 	if (!name || !name[0])
2050*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
2051*4a3b33f8SAndrii Nakryiko 
2052*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
2053*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
2054*4a3b33f8SAndrii Nakryiko 
2055*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_type);
2056*4a3b33f8SAndrii Nakryiko 	t = btf_add_type_mem(btf, sz);
2057*4a3b33f8SAndrii Nakryiko 	if (!t)
2058*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
2059*4a3b33f8SAndrii Nakryiko 
2060*4a3b33f8SAndrii Nakryiko 	name_off = btf__add_str(btf, name);
2061*4a3b33f8SAndrii Nakryiko 	if (name_off < 0)
2062*4a3b33f8SAndrii Nakryiko 		return name_off;
2063*4a3b33f8SAndrii Nakryiko 
2064*4a3b33f8SAndrii Nakryiko 	/* start with vlen=0, which will be update as var_secinfos are added */
2065*4a3b33f8SAndrii Nakryiko 	t->name_off = name_off;
2066*4a3b33f8SAndrii Nakryiko 	t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0);
2067*4a3b33f8SAndrii Nakryiko 	t->size = byte_sz;
2068*4a3b33f8SAndrii Nakryiko 
2069*4a3b33f8SAndrii Nakryiko 	err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
2070*4a3b33f8SAndrii Nakryiko 	if (err)
2071*4a3b33f8SAndrii Nakryiko 		return err;
2072*4a3b33f8SAndrii Nakryiko 
2073*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
2074*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
2075*4a3b33f8SAndrii Nakryiko 	btf->nr_types++;
2076*4a3b33f8SAndrii Nakryiko 	return btf->nr_types;
2077*4a3b33f8SAndrii Nakryiko }
2078*4a3b33f8SAndrii Nakryiko 
2079*4a3b33f8SAndrii Nakryiko /*
2080*4a3b33f8SAndrii Nakryiko  * Append new data section variable information entry for current DATASEC type:
2081*4a3b33f8SAndrii Nakryiko  *   - *var_type_id* - type ID, describing type of the variable;
2082*4a3b33f8SAndrii Nakryiko  *   - *offset* - variable offset within data section, in bytes;
2083*4a3b33f8SAndrii Nakryiko  *   - *byte_sz* - variable size, in bytes.
2084*4a3b33f8SAndrii Nakryiko  *
2085*4a3b33f8SAndrii Nakryiko  * Returns:
2086*4a3b33f8SAndrii Nakryiko  *   -  0, on success;
2087*4a3b33f8SAndrii Nakryiko  *   - <0, on error.
2088*4a3b33f8SAndrii Nakryiko  */
2089*4a3b33f8SAndrii Nakryiko int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz)
2090*4a3b33f8SAndrii Nakryiko {
2091*4a3b33f8SAndrii Nakryiko 	struct btf_type *t;
2092*4a3b33f8SAndrii Nakryiko 	struct btf_var_secinfo *v;
2093*4a3b33f8SAndrii Nakryiko 	int sz;
2094*4a3b33f8SAndrii Nakryiko 
2095*4a3b33f8SAndrii Nakryiko 	/* last type should be BTF_KIND_DATASEC */
2096*4a3b33f8SAndrii Nakryiko 	if (btf->nr_types == 0)
2097*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
2098*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
2099*4a3b33f8SAndrii Nakryiko 	if (!btf_is_datasec(t))
2100*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
2101*4a3b33f8SAndrii Nakryiko 
2102*4a3b33f8SAndrii Nakryiko 	if (validate_type_id(var_type_id))
2103*4a3b33f8SAndrii Nakryiko 		return -EINVAL;
2104*4a3b33f8SAndrii Nakryiko 
2105*4a3b33f8SAndrii Nakryiko 	/* decompose and invalidate raw data */
2106*4a3b33f8SAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
2107*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
2108*4a3b33f8SAndrii Nakryiko 
2109*4a3b33f8SAndrii Nakryiko 	sz = sizeof(struct btf_var_secinfo);
2110*4a3b33f8SAndrii Nakryiko 	v = btf_add_type_mem(btf, sz);
2111*4a3b33f8SAndrii Nakryiko 	if (!v)
2112*4a3b33f8SAndrii Nakryiko 		return -ENOMEM;
2113*4a3b33f8SAndrii Nakryiko 
2114*4a3b33f8SAndrii Nakryiko 	v->type = var_type_id;
2115*4a3b33f8SAndrii Nakryiko 	v->offset = offset;
2116*4a3b33f8SAndrii Nakryiko 	v->size = byte_sz;
2117*4a3b33f8SAndrii Nakryiko 
2118*4a3b33f8SAndrii Nakryiko 	/* update parent type's vlen */
2119*4a3b33f8SAndrii Nakryiko 	t = btf_type_by_id(btf, btf->nr_types);
2120*4a3b33f8SAndrii Nakryiko 	btf_type_inc_vlen(t);
2121*4a3b33f8SAndrii Nakryiko 
2122*4a3b33f8SAndrii Nakryiko 	btf->hdr->type_len += sz;
2123*4a3b33f8SAndrii Nakryiko 	btf->hdr->str_off += sz;
2124*4a3b33f8SAndrii Nakryiko 	return 0;
2125*4a3b33f8SAndrii Nakryiko }
2126*4a3b33f8SAndrii Nakryiko 
2127ae4ab4b4SAndrii Nakryiko struct btf_ext_sec_setup_param {
21283d650141SMartin KaFai Lau 	__u32 off;
21293d650141SMartin KaFai Lau 	__u32 len;
21303d650141SMartin KaFai Lau 	__u32 min_rec_size;
21313d650141SMartin KaFai Lau 	struct btf_ext_info *ext_info;
21323d650141SMartin KaFai Lau 	const char *desc;
21333d650141SMartin KaFai Lau };
21343d650141SMartin KaFai Lau 
2135ae4ab4b4SAndrii Nakryiko static int btf_ext_setup_info(struct btf_ext *btf_ext,
2136ae4ab4b4SAndrii Nakryiko 			      struct btf_ext_sec_setup_param *ext_sec)
21372993e051SYonghong Song {
21383d650141SMartin KaFai Lau 	const struct btf_ext_info_sec *sinfo;
21393d650141SMartin KaFai Lau 	struct btf_ext_info *ext_info;
2140f0187f0bSMartin KaFai Lau 	__u32 info_left, record_size;
2141f0187f0bSMartin KaFai Lau 	/* The start of the info sec (including the __u32 record_size). */
2142ae4ab4b4SAndrii Nakryiko 	void *info;
2143f0187f0bSMartin KaFai Lau 
21444cedc0daSAndrii Nakryiko 	if (ext_sec->len == 0)
21454cedc0daSAndrii Nakryiko 		return 0;
21464cedc0daSAndrii Nakryiko 
21473d650141SMartin KaFai Lau 	if (ext_sec->off & 0x03) {
21488461ef8bSYonghong Song 		pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n",
21493d650141SMartin KaFai Lau 		     ext_sec->desc);
2150f0187f0bSMartin KaFai Lau 		return -EINVAL;
2151f0187f0bSMartin KaFai Lau 	}
2152f0187f0bSMartin KaFai Lau 
2153ae4ab4b4SAndrii Nakryiko 	info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off;
2154ae4ab4b4SAndrii Nakryiko 	info_left = ext_sec->len;
2155ae4ab4b4SAndrii Nakryiko 
2156ae4ab4b4SAndrii Nakryiko 	if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) {
21578461ef8bSYonghong Song 		pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n",
21583d650141SMartin KaFai Lau 			 ext_sec->desc, ext_sec->off, ext_sec->len);
2159f0187f0bSMartin KaFai Lau 		return -EINVAL;
2160f0187f0bSMartin KaFai Lau 	}
2161f0187f0bSMartin KaFai Lau 
21623d650141SMartin KaFai Lau 	/* At least a record size */
2163f0187f0bSMartin KaFai Lau 	if (info_left < sizeof(__u32)) {
21648461ef8bSYonghong Song 		pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc);
21652993e051SYonghong Song 		return -EINVAL;
21662993e051SYonghong Song 	}
21672993e051SYonghong Song 
2168f0187f0bSMartin KaFai Lau 	/* The record size needs to meet the minimum standard */
2169f0187f0bSMartin KaFai Lau 	record_size = *(__u32 *)info;
21703d650141SMartin KaFai Lau 	if (record_size < ext_sec->min_rec_size ||
2171f0187f0bSMartin KaFai Lau 	    record_size & 0x03) {
21728461ef8bSYonghong Song 		pr_debug("%s section in .BTF.ext has invalid record size %u\n",
21733d650141SMartin KaFai Lau 			 ext_sec->desc, record_size);
21742993e051SYonghong Song 		return -EINVAL;
21752993e051SYonghong Song 	}
21762993e051SYonghong Song 
2177f0187f0bSMartin KaFai Lau 	sinfo = info + sizeof(__u32);
2178f0187f0bSMartin KaFai Lau 	info_left -= sizeof(__u32);
21792993e051SYonghong Song 
21803d650141SMartin KaFai Lau 	/* If no records, return failure now so .BTF.ext won't be used. */
2181f0187f0bSMartin KaFai Lau 	if (!info_left) {
21828461ef8bSYonghong Song 		pr_debug("%s section in .BTF.ext has no records", ext_sec->desc);
21832993e051SYonghong Song 		return -EINVAL;
21842993e051SYonghong Song 	}
21852993e051SYonghong Song 
2186f0187f0bSMartin KaFai Lau 	while (info_left) {
21873d650141SMartin KaFai Lau 		unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
2188f0187f0bSMartin KaFai Lau 		__u64 total_record_size;
2189f0187f0bSMartin KaFai Lau 		__u32 num_records;
2190f0187f0bSMartin KaFai Lau 
2191f0187f0bSMartin KaFai Lau 		if (info_left < sec_hdrlen) {
21928461ef8bSYonghong Song 			pr_debug("%s section header is not found in .BTF.ext\n",
21933d650141SMartin KaFai Lau 			     ext_sec->desc);
21942993e051SYonghong Song 			return -EINVAL;
21952993e051SYonghong Song 		}
21962993e051SYonghong Song 
21973d650141SMartin KaFai Lau 		num_records = sinfo->num_info;
21982993e051SYonghong Song 		if (num_records == 0) {
21998461ef8bSYonghong Song 			pr_debug("%s section has incorrect num_records in .BTF.ext\n",
22003d650141SMartin KaFai Lau 			     ext_sec->desc);
22012993e051SYonghong Song 			return -EINVAL;
22022993e051SYonghong Song 		}
22032993e051SYonghong Song 
22042993e051SYonghong Song 		total_record_size = sec_hdrlen +
22052993e051SYonghong Song 				    (__u64)num_records * record_size;
2206f0187f0bSMartin KaFai Lau 		if (info_left < total_record_size) {
22078461ef8bSYonghong Song 			pr_debug("%s section has incorrect num_records in .BTF.ext\n",
22083d650141SMartin KaFai Lau 			     ext_sec->desc);
22092993e051SYonghong Song 			return -EINVAL;
22102993e051SYonghong Song 		}
22112993e051SYonghong Song 
2212f0187f0bSMartin KaFai Lau 		info_left -= total_record_size;
22132993e051SYonghong Song 		sinfo = (void *)sinfo + total_record_size;
22142993e051SYonghong Song 	}
22152993e051SYonghong Song 
22163d650141SMartin KaFai Lau 	ext_info = ext_sec->ext_info;
22173d650141SMartin KaFai Lau 	ext_info->len = ext_sec->len - sizeof(__u32);
22183d650141SMartin KaFai Lau 	ext_info->rec_size = record_size;
2219ae4ab4b4SAndrii Nakryiko 	ext_info->info = info + sizeof(__u32);
2220f0187f0bSMartin KaFai Lau 
22212993e051SYonghong Song 	return 0;
22222993e051SYonghong Song }
22232993e051SYonghong Song 
2224ae4ab4b4SAndrii Nakryiko static int btf_ext_setup_func_info(struct btf_ext *btf_ext)
22253d650141SMartin KaFai Lau {
2226ae4ab4b4SAndrii Nakryiko 	struct btf_ext_sec_setup_param param = {
2227ae4ab4b4SAndrii Nakryiko 		.off = btf_ext->hdr->func_info_off,
2228ae4ab4b4SAndrii Nakryiko 		.len = btf_ext->hdr->func_info_len,
22293d650141SMartin KaFai Lau 		.min_rec_size = sizeof(struct bpf_func_info_min),
22303d650141SMartin KaFai Lau 		.ext_info = &btf_ext->func_info,
22313d650141SMartin KaFai Lau 		.desc = "func_info"
22323d650141SMartin KaFai Lau 	};
22333d650141SMartin KaFai Lau 
2234ae4ab4b4SAndrii Nakryiko 	return btf_ext_setup_info(btf_ext, &param);
22353d650141SMartin KaFai Lau }
22363d650141SMartin KaFai Lau 
2237ae4ab4b4SAndrii Nakryiko static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
22383d650141SMartin KaFai Lau {
2239ae4ab4b4SAndrii Nakryiko 	struct btf_ext_sec_setup_param param = {
2240ae4ab4b4SAndrii Nakryiko 		.off = btf_ext->hdr->line_info_off,
2241ae4ab4b4SAndrii Nakryiko 		.len = btf_ext->hdr->line_info_len,
22423d650141SMartin KaFai Lau 		.min_rec_size = sizeof(struct bpf_line_info_min),
22433d650141SMartin KaFai Lau 		.ext_info = &btf_ext->line_info,
22443d650141SMartin KaFai Lau 		.desc = "line_info",
22453d650141SMartin KaFai Lau 	};
22463d650141SMartin KaFai Lau 
2247ae4ab4b4SAndrii Nakryiko 	return btf_ext_setup_info(btf_ext, &param);
22483d650141SMartin KaFai Lau }
22493d650141SMartin KaFai Lau 
225028b93c64SAndrii Nakryiko static int btf_ext_setup_core_relos(struct btf_ext *btf_ext)
22514cedc0daSAndrii Nakryiko {
22524cedc0daSAndrii Nakryiko 	struct btf_ext_sec_setup_param param = {
225328b93c64SAndrii Nakryiko 		.off = btf_ext->hdr->core_relo_off,
225428b93c64SAndrii Nakryiko 		.len = btf_ext->hdr->core_relo_len,
225528b93c64SAndrii Nakryiko 		.min_rec_size = sizeof(struct bpf_core_relo),
225628b93c64SAndrii Nakryiko 		.ext_info = &btf_ext->core_relo_info,
225728b93c64SAndrii Nakryiko 		.desc = "core_relo",
22584cedc0daSAndrii Nakryiko 	};
22594cedc0daSAndrii Nakryiko 
22604cedc0daSAndrii Nakryiko 	return btf_ext_setup_info(btf_ext, &param);
22614cedc0daSAndrii Nakryiko }
22624cedc0daSAndrii Nakryiko 
22638461ef8bSYonghong Song static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
22642993e051SYonghong Song {
22652993e051SYonghong Song 	const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
22662993e051SYonghong Song 
22674cedc0daSAndrii Nakryiko 	if (data_size < offsetofend(struct btf_ext_header, hdr_len) ||
22682993e051SYonghong Song 	    data_size < hdr->hdr_len) {
22698461ef8bSYonghong Song 		pr_debug("BTF.ext header not found");
22702993e051SYonghong Song 		return -EINVAL;
22712993e051SYonghong Song 	}
22722993e051SYonghong Song 
22732993e051SYonghong Song 	if (hdr->magic != BTF_MAGIC) {
22748461ef8bSYonghong Song 		pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic);
22752993e051SYonghong Song 		return -EINVAL;
22762993e051SYonghong Song 	}
22772993e051SYonghong Song 
22782993e051SYonghong Song 	if (hdr->version != BTF_VERSION) {
22798461ef8bSYonghong Song 		pr_debug("Unsupported BTF.ext version:%u\n", hdr->version);
22802993e051SYonghong Song 		return -ENOTSUP;
22812993e051SYonghong Song 	}
22822993e051SYonghong Song 
22832993e051SYonghong Song 	if (hdr->flags) {
22848461ef8bSYonghong Song 		pr_debug("Unsupported BTF.ext flags:%x\n", hdr->flags);
22852993e051SYonghong Song 		return -ENOTSUP;
22862993e051SYonghong Song 	}
22872993e051SYonghong Song 
2288f0187f0bSMartin KaFai Lau 	if (data_size == hdr->hdr_len) {
22898461ef8bSYonghong Song 		pr_debug("BTF.ext has no data\n");
22902993e051SYonghong Song 		return -EINVAL;
22912993e051SYonghong Song 	}
22922993e051SYonghong Song 
2293f0187f0bSMartin KaFai Lau 	return 0;
22942993e051SYonghong Song }
22952993e051SYonghong Song 
22962993e051SYonghong Song void btf_ext__free(struct btf_ext *btf_ext)
22972993e051SYonghong Song {
229850450fc7SAndrii Nakryiko 	if (IS_ERR_OR_NULL(btf_ext))
22992993e051SYonghong Song 		return;
2300ae4ab4b4SAndrii Nakryiko 	free(btf_ext->data);
23012993e051SYonghong Song 	free(btf_ext);
23022993e051SYonghong Song }
23032993e051SYonghong Song 
23048461ef8bSYonghong Song struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
23052993e051SYonghong Song {
23062993e051SYonghong Song 	struct btf_ext *btf_ext;
23072993e051SYonghong Song 	int err;
23082993e051SYonghong Song 
23098461ef8bSYonghong Song 	err = btf_ext_parse_hdr(data, size);
23102993e051SYonghong Song 	if (err)
23112993e051SYonghong Song 		return ERR_PTR(err);
23122993e051SYonghong Song 
23132993e051SYonghong Song 	btf_ext = calloc(1, sizeof(struct btf_ext));
23142993e051SYonghong Song 	if (!btf_ext)
23152993e051SYonghong Song 		return ERR_PTR(-ENOMEM);
23162993e051SYonghong Song 
2317ae4ab4b4SAndrii Nakryiko 	btf_ext->data_size = size;
2318ae4ab4b4SAndrii Nakryiko 	btf_ext->data = malloc(size);
2319ae4ab4b4SAndrii Nakryiko 	if (!btf_ext->data) {
2320ae4ab4b4SAndrii Nakryiko 		err = -ENOMEM;
2321ae4ab4b4SAndrii Nakryiko 		goto done;
23222993e051SYonghong Song 	}
2323ae4ab4b4SAndrii Nakryiko 	memcpy(btf_ext->data, data, size);
23242993e051SYonghong Song 
23254cedc0daSAndrii Nakryiko 	if (btf_ext->hdr->hdr_len <
23264cedc0daSAndrii Nakryiko 	    offsetofend(struct btf_ext_header, line_info_len))
23274cedc0daSAndrii Nakryiko 		goto done;
2328ae4ab4b4SAndrii Nakryiko 	err = btf_ext_setup_func_info(btf_ext);
2329ae4ab4b4SAndrii Nakryiko 	if (err)
2330ae4ab4b4SAndrii Nakryiko 		goto done;
2331ae4ab4b4SAndrii Nakryiko 
2332ae4ab4b4SAndrii Nakryiko 	err = btf_ext_setup_line_info(btf_ext);
2333ae4ab4b4SAndrii Nakryiko 	if (err)
2334ae4ab4b4SAndrii Nakryiko 		goto done;
2335ae4ab4b4SAndrii Nakryiko 
233628b93c64SAndrii Nakryiko 	if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
23374cedc0daSAndrii Nakryiko 		goto done;
233828b93c64SAndrii Nakryiko 	err = btf_ext_setup_core_relos(btf_ext);
23394cedc0daSAndrii Nakryiko 	if (err)
23404cedc0daSAndrii Nakryiko 		goto done;
23414cedc0daSAndrii Nakryiko 
2342ae4ab4b4SAndrii Nakryiko done:
23433d650141SMartin KaFai Lau 	if (err) {
23443d650141SMartin KaFai Lau 		btf_ext__free(btf_ext);
23453d650141SMartin KaFai Lau 		return ERR_PTR(err);
23463d650141SMartin KaFai Lau 	}
23473d650141SMartin KaFai Lau 
23482993e051SYonghong Song 	return btf_ext;
23492993e051SYonghong Song }
23502993e051SYonghong Song 
2351ae4ab4b4SAndrii Nakryiko const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size)
2352ae4ab4b4SAndrii Nakryiko {
2353ae4ab4b4SAndrii Nakryiko 	*size = btf_ext->data_size;
2354ae4ab4b4SAndrii Nakryiko 	return btf_ext->data;
2355ae4ab4b4SAndrii Nakryiko }
2356ae4ab4b4SAndrii Nakryiko 
23573d650141SMartin KaFai Lau static int btf_ext_reloc_info(const struct btf *btf,
23583d650141SMartin KaFai Lau 			      const struct btf_ext_info *ext_info,
23592993e051SYonghong Song 			      const char *sec_name, __u32 insns_cnt,
23603d650141SMartin KaFai Lau 			      void **info, __u32 *cnt)
23612993e051SYonghong Song {
23623d650141SMartin KaFai Lau 	__u32 sec_hdrlen = sizeof(struct btf_ext_info_sec);
23633d650141SMartin KaFai Lau 	__u32 i, record_size, existing_len, records_len;
23643d650141SMartin KaFai Lau 	struct btf_ext_info_sec *sinfo;
23652993e051SYonghong Song 	const char *info_sec_name;
23662993e051SYonghong Song 	__u64 remain_len;
23672993e051SYonghong Song 	void *data;
23682993e051SYonghong Song 
23693d650141SMartin KaFai Lau 	record_size = ext_info->rec_size;
23703d650141SMartin KaFai Lau 	sinfo = ext_info->info;
23713d650141SMartin KaFai Lau 	remain_len = ext_info->len;
23722993e051SYonghong Song 	while (remain_len > 0) {
23733d650141SMartin KaFai Lau 		records_len = sinfo->num_info * record_size;
23742993e051SYonghong Song 		info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off);
23752993e051SYonghong Song 		if (strcmp(info_sec_name, sec_name)) {
23762993e051SYonghong Song 			remain_len -= sec_hdrlen + records_len;
23772993e051SYonghong Song 			sinfo = (void *)sinfo + sec_hdrlen + records_len;
23782993e051SYonghong Song 			continue;
23792993e051SYonghong Song 		}
23802993e051SYonghong Song 
23813d650141SMartin KaFai Lau 		existing_len = (*cnt) * record_size;
23823d650141SMartin KaFai Lau 		data = realloc(*info, existing_len + records_len);
23832993e051SYonghong Song 		if (!data)
23842993e051SYonghong Song 			return -ENOMEM;
23852993e051SYonghong Song 
23863d650141SMartin KaFai Lau 		memcpy(data + existing_len, sinfo->data, records_len);
238784ecc1f9SMartin KaFai Lau 		/* adjust insn_off only, the rest data will be passed
23882993e051SYonghong Song 		 * to the kernel.
23892993e051SYonghong Song 		 */
23903d650141SMartin KaFai Lau 		for (i = 0; i < sinfo->num_info; i++) {
23913d650141SMartin KaFai Lau 			__u32 *insn_off;
23922993e051SYonghong Song 
23933d650141SMartin KaFai Lau 			insn_off = data + existing_len + (i * record_size);
23943d650141SMartin KaFai Lau 			*insn_off = *insn_off / sizeof(struct bpf_insn) +
23952993e051SYonghong Song 				insns_cnt;
23962993e051SYonghong Song 		}
23973d650141SMartin KaFai Lau 		*info = data;
23983d650141SMartin KaFai Lau 		*cnt += sinfo->num_info;
23992993e051SYonghong Song 		return 0;
24002993e051SYonghong Song 	}
24012993e051SYonghong Song 
2402f0187f0bSMartin KaFai Lau 	return -ENOENT;
2403f0187f0bSMartin KaFai Lau }
2404f0187f0bSMartin KaFai Lau 
2405ae4ab4b4SAndrii Nakryiko int btf_ext__reloc_func_info(const struct btf *btf,
2406ae4ab4b4SAndrii Nakryiko 			     const struct btf_ext *btf_ext,
24073d650141SMartin KaFai Lau 			     const char *sec_name, __u32 insns_cnt,
24083d650141SMartin KaFai Lau 			     void **func_info, __u32 *cnt)
24093d650141SMartin KaFai Lau {
24103d650141SMartin KaFai Lau 	return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name,
24113d650141SMartin KaFai Lau 				  insns_cnt, func_info, cnt);
24123d650141SMartin KaFai Lau }
24133d650141SMartin KaFai Lau 
2414ae4ab4b4SAndrii Nakryiko int btf_ext__reloc_line_info(const struct btf *btf,
2415ae4ab4b4SAndrii Nakryiko 			     const struct btf_ext *btf_ext,
24163d650141SMartin KaFai Lau 			     const char *sec_name, __u32 insns_cnt,
24173d650141SMartin KaFai Lau 			     void **line_info, __u32 *cnt)
24183d650141SMartin KaFai Lau {
24193d650141SMartin KaFai Lau 	return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name,
24203d650141SMartin KaFai Lau 				  insns_cnt, line_info, cnt);
24213d650141SMartin KaFai Lau }
24223d650141SMartin KaFai Lau 
2423f0187f0bSMartin KaFai Lau __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext)
2424f0187f0bSMartin KaFai Lau {
24253d650141SMartin KaFai Lau 	return btf_ext->func_info.rec_size;
24263d650141SMartin KaFai Lau }
24273d650141SMartin KaFai Lau 
24283d650141SMartin KaFai Lau __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext)
24293d650141SMartin KaFai Lau {
24303d650141SMartin KaFai Lau 	return btf_ext->line_info.rec_size;
24312993e051SYonghong Song }
2432d5caef5bSAndrii Nakryiko 
2433d5caef5bSAndrii Nakryiko struct btf_dedup;
2434d5caef5bSAndrii Nakryiko 
2435d5caef5bSAndrii Nakryiko static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
2436d5caef5bSAndrii Nakryiko 				       const struct btf_dedup_opts *opts);
2437d5caef5bSAndrii Nakryiko static void btf_dedup_free(struct btf_dedup *d);
2438d5caef5bSAndrii Nakryiko static int btf_dedup_strings(struct btf_dedup *d);
2439d5caef5bSAndrii Nakryiko static int btf_dedup_prim_types(struct btf_dedup *d);
2440d5caef5bSAndrii Nakryiko static int btf_dedup_struct_types(struct btf_dedup *d);
2441d5caef5bSAndrii Nakryiko static int btf_dedup_ref_types(struct btf_dedup *d);
2442d5caef5bSAndrii Nakryiko static int btf_dedup_compact_types(struct btf_dedup *d);
2443d5caef5bSAndrii Nakryiko static int btf_dedup_remap_types(struct btf_dedup *d);
2444d5caef5bSAndrii Nakryiko 
2445d5caef5bSAndrii Nakryiko /*
2446d5caef5bSAndrii Nakryiko  * Deduplicate BTF types and strings.
2447d5caef5bSAndrii Nakryiko  *
2448d5caef5bSAndrii Nakryiko  * BTF dedup algorithm takes as an input `struct btf` representing `.BTF` ELF
2449d5caef5bSAndrii Nakryiko  * section with all BTF type descriptors and string data. It overwrites that
2450d5caef5bSAndrii Nakryiko  * memory in-place with deduplicated types and strings without any loss of
2451d5caef5bSAndrii Nakryiko  * information. If optional `struct btf_ext` representing '.BTF.ext' ELF section
2452d5caef5bSAndrii Nakryiko  * is provided, all the strings referenced from .BTF.ext section are honored
2453d5caef5bSAndrii Nakryiko  * and updated to point to the right offsets after deduplication.
2454d5caef5bSAndrii Nakryiko  *
2455d5caef5bSAndrii Nakryiko  * If function returns with error, type/string data might be garbled and should
2456d5caef5bSAndrii Nakryiko  * be discarded.
2457d5caef5bSAndrii Nakryiko  *
2458d5caef5bSAndrii Nakryiko  * More verbose and detailed description of both problem btf_dedup is solving,
2459d5caef5bSAndrii Nakryiko  * as well as solution could be found at:
2460d5caef5bSAndrii Nakryiko  * https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html
2461d5caef5bSAndrii Nakryiko  *
2462d5caef5bSAndrii Nakryiko  * Problem description and justification
2463d5caef5bSAndrii Nakryiko  * =====================================
2464d5caef5bSAndrii Nakryiko  *
2465d5caef5bSAndrii Nakryiko  * BTF type information is typically emitted either as a result of conversion
2466d5caef5bSAndrii Nakryiko  * from DWARF to BTF or directly by compiler. In both cases, each compilation
2467d5caef5bSAndrii Nakryiko  * unit contains information about a subset of all the types that are used
2468d5caef5bSAndrii Nakryiko  * in an application. These subsets are frequently overlapping and contain a lot
2469d5caef5bSAndrii Nakryiko  * of duplicated information when later concatenated together into a single
2470d5caef5bSAndrii Nakryiko  * binary. This algorithm ensures that each unique type is represented by single
2471d5caef5bSAndrii Nakryiko  * BTF type descriptor, greatly reducing resulting size of BTF data.
2472d5caef5bSAndrii Nakryiko  *
2473d5caef5bSAndrii Nakryiko  * Compilation unit isolation and subsequent duplication of data is not the only
2474d5caef5bSAndrii Nakryiko  * problem. The same type hierarchy (e.g., struct and all the type that struct
2475d5caef5bSAndrii Nakryiko  * references) in different compilation units can be represented in BTF to
2476d5caef5bSAndrii Nakryiko  * various degrees of completeness (or, rather, incompleteness) due to
2477d5caef5bSAndrii Nakryiko  * struct/union forward declarations.
2478d5caef5bSAndrii Nakryiko  *
2479d5caef5bSAndrii Nakryiko  * Let's take a look at an example, that we'll use to better understand the
2480d5caef5bSAndrii Nakryiko  * problem (and solution). Suppose we have two compilation units, each using
2481d5caef5bSAndrii Nakryiko  * same `struct S`, but each of them having incomplete type information about
2482d5caef5bSAndrii Nakryiko  * struct's fields:
2483d5caef5bSAndrii Nakryiko  *
2484d5caef5bSAndrii Nakryiko  * // CU #1:
2485d5caef5bSAndrii Nakryiko  * struct S;
2486d5caef5bSAndrii Nakryiko  * struct A {
2487d5caef5bSAndrii Nakryiko  *	int a;
2488d5caef5bSAndrii Nakryiko  *	struct A* self;
2489d5caef5bSAndrii Nakryiko  *	struct S* parent;
2490d5caef5bSAndrii Nakryiko  * };
2491d5caef5bSAndrii Nakryiko  * struct B;
2492d5caef5bSAndrii Nakryiko  * struct S {
2493d5caef5bSAndrii Nakryiko  *	struct A* a_ptr;
2494d5caef5bSAndrii Nakryiko  *	struct B* b_ptr;
2495d5caef5bSAndrii Nakryiko  * };
2496d5caef5bSAndrii Nakryiko  *
2497d5caef5bSAndrii Nakryiko  * // CU #2:
2498d5caef5bSAndrii Nakryiko  * struct S;
2499d5caef5bSAndrii Nakryiko  * struct A;
2500d5caef5bSAndrii Nakryiko  * struct B {
2501d5caef5bSAndrii Nakryiko  *	int b;
2502d5caef5bSAndrii Nakryiko  *	struct B* self;
2503d5caef5bSAndrii Nakryiko  *	struct S* parent;
2504d5caef5bSAndrii Nakryiko  * };
2505d5caef5bSAndrii Nakryiko  * struct S {
2506d5caef5bSAndrii Nakryiko  *	struct A* a_ptr;
2507d5caef5bSAndrii Nakryiko  *	struct B* b_ptr;
2508d5caef5bSAndrii Nakryiko  * };
2509d5caef5bSAndrii Nakryiko  *
2510d5caef5bSAndrii Nakryiko  * In case of CU #1, BTF data will know only that `struct B` exist (but no
2511d5caef5bSAndrii Nakryiko  * more), but will know the complete type information about `struct A`. While
2512d5caef5bSAndrii Nakryiko  * for CU #2, it will know full type information about `struct B`, but will
2513d5caef5bSAndrii Nakryiko  * only know about forward declaration of `struct A` (in BTF terms, it will
2514d5caef5bSAndrii Nakryiko  * have `BTF_KIND_FWD` type descriptor with name `B`).
2515d5caef5bSAndrii Nakryiko  *
2516d5caef5bSAndrii Nakryiko  * This compilation unit isolation means that it's possible that there is no
2517d5caef5bSAndrii Nakryiko  * single CU with complete type information describing structs `S`, `A`, and
2518d5caef5bSAndrii Nakryiko  * `B`. Also, we might get tons of duplicated and redundant type information.
2519d5caef5bSAndrii Nakryiko  *
2520d5caef5bSAndrii Nakryiko  * Additional complication we need to keep in mind comes from the fact that
2521d5caef5bSAndrii Nakryiko  * types, in general, can form graphs containing cycles, not just DAGs.
2522d5caef5bSAndrii Nakryiko  *
2523d5caef5bSAndrii Nakryiko  * While algorithm does deduplication, it also merges and resolves type
2524d5caef5bSAndrii Nakryiko  * information (unless disabled throught `struct btf_opts`), whenever possible.
2525d5caef5bSAndrii Nakryiko  * E.g., in the example above with two compilation units having partial type
2526d5caef5bSAndrii Nakryiko  * information for structs `A` and `B`, the output of algorithm will emit
2527d5caef5bSAndrii Nakryiko  * a single copy of each BTF type that describes structs `A`, `B`, and `S`
2528d5caef5bSAndrii Nakryiko  * (as well as type information for `int` and pointers), as if they were defined
2529d5caef5bSAndrii Nakryiko  * in a single compilation unit as:
2530d5caef5bSAndrii Nakryiko  *
2531d5caef5bSAndrii Nakryiko  * struct A {
2532d5caef5bSAndrii Nakryiko  *	int a;
2533d5caef5bSAndrii Nakryiko  *	struct A* self;
2534d5caef5bSAndrii Nakryiko  *	struct S* parent;
2535d5caef5bSAndrii Nakryiko  * };
2536d5caef5bSAndrii Nakryiko  * struct B {
2537d5caef5bSAndrii Nakryiko  *	int b;
2538d5caef5bSAndrii Nakryiko  *	struct B* self;
2539d5caef5bSAndrii Nakryiko  *	struct S* parent;
2540d5caef5bSAndrii Nakryiko  * };
2541d5caef5bSAndrii Nakryiko  * struct S {
2542d5caef5bSAndrii Nakryiko  *	struct A* a_ptr;
2543d5caef5bSAndrii Nakryiko  *	struct B* b_ptr;
2544d5caef5bSAndrii Nakryiko  * };
2545d5caef5bSAndrii Nakryiko  *
2546d5caef5bSAndrii Nakryiko  * Algorithm summary
2547d5caef5bSAndrii Nakryiko  * =================
2548d5caef5bSAndrii Nakryiko  *
2549d5caef5bSAndrii Nakryiko  * Algorithm completes its work in 6 separate passes:
2550d5caef5bSAndrii Nakryiko  *
2551d5caef5bSAndrii Nakryiko  * 1. Strings deduplication.
2552d5caef5bSAndrii Nakryiko  * 2. Primitive types deduplication (int, enum, fwd).
2553d5caef5bSAndrii Nakryiko  * 3. Struct/union types deduplication.
2554d5caef5bSAndrii Nakryiko  * 4. Reference types deduplication (pointers, typedefs, arrays, funcs, func
2555d5caef5bSAndrii Nakryiko  *    protos, and const/volatile/restrict modifiers).
2556d5caef5bSAndrii Nakryiko  * 5. Types compaction.
2557d5caef5bSAndrii Nakryiko  * 6. Types remapping.
2558d5caef5bSAndrii Nakryiko  *
2559d5caef5bSAndrii Nakryiko  * Algorithm determines canonical type descriptor, which is a single
2560d5caef5bSAndrii Nakryiko  * representative type for each truly unique type. This canonical type is the
2561d5caef5bSAndrii Nakryiko  * one that will go into final deduplicated BTF type information. For
2562d5caef5bSAndrii Nakryiko  * struct/unions, it is also the type that algorithm will merge additional type
2563d5caef5bSAndrii Nakryiko  * information into (while resolving FWDs), as it discovers it from data in
2564d5caef5bSAndrii Nakryiko  * other CUs. Each input BTF type eventually gets either mapped to itself, if
2565d5caef5bSAndrii Nakryiko  * that type is canonical, or to some other type, if that type is equivalent
2566d5caef5bSAndrii Nakryiko  * and was chosen as canonical representative. This mapping is stored in
2567d5caef5bSAndrii Nakryiko  * `btf_dedup->map` array. This map is also used to record STRUCT/UNION that
2568d5caef5bSAndrii Nakryiko  * FWD type got resolved to.
2569d5caef5bSAndrii Nakryiko  *
2570d5caef5bSAndrii Nakryiko  * To facilitate fast discovery of canonical types, we also maintain canonical
2571d5caef5bSAndrii Nakryiko  * index (`btf_dedup->dedup_table`), which maps type descriptor's signature hash
2572d5caef5bSAndrii Nakryiko  * (i.e., hashed kind, name, size, fields, etc) into a list of canonical types
2573d5caef5bSAndrii Nakryiko  * that match that signature. With sufficiently good choice of type signature
2574d5caef5bSAndrii Nakryiko  * hashing function, we can limit number of canonical types for each unique type
2575d5caef5bSAndrii Nakryiko  * signature to a very small number, allowing to find canonical type for any
2576d5caef5bSAndrii Nakryiko  * duplicated type very quickly.
2577d5caef5bSAndrii Nakryiko  *
2578d5caef5bSAndrii Nakryiko  * Struct/union deduplication is the most critical part and algorithm for
2579d5caef5bSAndrii Nakryiko  * deduplicating structs/unions is described in greater details in comments for
2580d5caef5bSAndrii Nakryiko  * `btf_dedup_is_equiv` function.
2581d5caef5bSAndrii Nakryiko  */
2582d5caef5bSAndrii Nakryiko int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
2583d5caef5bSAndrii Nakryiko 	       const struct btf_dedup_opts *opts)
2584d5caef5bSAndrii Nakryiko {
2585d5caef5bSAndrii Nakryiko 	struct btf_dedup *d = btf_dedup_new(btf, btf_ext, opts);
2586d5caef5bSAndrii Nakryiko 	int err;
2587d5caef5bSAndrii Nakryiko 
2588d5caef5bSAndrii Nakryiko 	if (IS_ERR(d)) {
2589d5caef5bSAndrii Nakryiko 		pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d));
2590d5caef5bSAndrii Nakryiko 		return -EINVAL;
2591d5caef5bSAndrii Nakryiko 	}
2592d5caef5bSAndrii Nakryiko 
2593919d2b1dSAndrii Nakryiko 	if (btf_ensure_modifiable(btf))
2594919d2b1dSAndrii Nakryiko 		return -ENOMEM;
2595919d2b1dSAndrii Nakryiko 
2596d5caef5bSAndrii Nakryiko 	err = btf_dedup_strings(d);
2597d5caef5bSAndrii Nakryiko 	if (err < 0) {
2598d5caef5bSAndrii Nakryiko 		pr_debug("btf_dedup_strings failed:%d\n", err);
2599d5caef5bSAndrii Nakryiko 		goto done;
2600d5caef5bSAndrii Nakryiko 	}
2601d5caef5bSAndrii Nakryiko 	err = btf_dedup_prim_types(d);
2602d5caef5bSAndrii Nakryiko 	if (err < 0) {
2603d5caef5bSAndrii Nakryiko 		pr_debug("btf_dedup_prim_types failed:%d\n", err);
2604d5caef5bSAndrii Nakryiko 		goto done;
2605d5caef5bSAndrii Nakryiko 	}
2606d5caef5bSAndrii Nakryiko 	err = btf_dedup_struct_types(d);
2607d5caef5bSAndrii Nakryiko 	if (err < 0) {
2608d5caef5bSAndrii Nakryiko 		pr_debug("btf_dedup_struct_types failed:%d\n", err);
2609d5caef5bSAndrii Nakryiko 		goto done;
2610d5caef5bSAndrii Nakryiko 	}
2611d5caef5bSAndrii Nakryiko 	err = btf_dedup_ref_types(d);
2612d5caef5bSAndrii Nakryiko 	if (err < 0) {
2613d5caef5bSAndrii Nakryiko 		pr_debug("btf_dedup_ref_types failed:%d\n", err);
2614d5caef5bSAndrii Nakryiko 		goto done;
2615d5caef5bSAndrii Nakryiko 	}
2616d5caef5bSAndrii Nakryiko 	err = btf_dedup_compact_types(d);
2617d5caef5bSAndrii Nakryiko 	if (err < 0) {
2618d5caef5bSAndrii Nakryiko 		pr_debug("btf_dedup_compact_types failed:%d\n", err);
2619d5caef5bSAndrii Nakryiko 		goto done;
2620d5caef5bSAndrii Nakryiko 	}
2621d5caef5bSAndrii Nakryiko 	err = btf_dedup_remap_types(d);
2622d5caef5bSAndrii Nakryiko 	if (err < 0) {
2623d5caef5bSAndrii Nakryiko 		pr_debug("btf_dedup_remap_types failed:%d\n", err);
2624d5caef5bSAndrii Nakryiko 		goto done;
2625d5caef5bSAndrii Nakryiko 	}
2626d5caef5bSAndrii Nakryiko 
2627d5caef5bSAndrii Nakryiko done:
2628d5caef5bSAndrii Nakryiko 	btf_dedup_free(d);
2629d5caef5bSAndrii Nakryiko 	return err;
2630d5caef5bSAndrii Nakryiko }
2631d5caef5bSAndrii Nakryiko 
2632d5caef5bSAndrii Nakryiko #define BTF_UNPROCESSED_ID ((__u32)-1)
2633d5caef5bSAndrii Nakryiko #define BTF_IN_PROGRESS_ID ((__u32)-2)
2634d5caef5bSAndrii Nakryiko 
2635d5caef5bSAndrii Nakryiko struct btf_dedup {
2636d5caef5bSAndrii Nakryiko 	/* .BTF section to be deduped in-place */
2637d5caef5bSAndrii Nakryiko 	struct btf *btf;
2638d5caef5bSAndrii Nakryiko 	/*
2639d5caef5bSAndrii Nakryiko 	 * Optional .BTF.ext section. When provided, any strings referenced
2640d5caef5bSAndrii Nakryiko 	 * from it will be taken into account when deduping strings
2641d5caef5bSAndrii Nakryiko 	 */
2642d5caef5bSAndrii Nakryiko 	struct btf_ext *btf_ext;
2643d5caef5bSAndrii Nakryiko 	/*
2644d5caef5bSAndrii Nakryiko 	 * This is a map from any type's signature hash to a list of possible
2645d5caef5bSAndrii Nakryiko 	 * canonical representative type candidates. Hash collisions are
2646d5caef5bSAndrii Nakryiko 	 * ignored, so even types of various kinds can share same list of
2647d5caef5bSAndrii Nakryiko 	 * candidates, which is fine because we rely on subsequent
2648d5caef5bSAndrii Nakryiko 	 * btf_xxx_equal() checks to authoritatively verify type equality.
2649d5caef5bSAndrii Nakryiko 	 */
26502fc3fc0bSAndrii Nakryiko 	struct hashmap *dedup_table;
2651d5caef5bSAndrii Nakryiko 	/* Canonical types map */
2652d5caef5bSAndrii Nakryiko 	__u32 *map;
2653d5caef5bSAndrii Nakryiko 	/* Hypothetical mapping, used during type graph equivalence checks */
2654d5caef5bSAndrii Nakryiko 	__u32 *hypot_map;
2655d5caef5bSAndrii Nakryiko 	__u32 *hypot_list;
2656d5caef5bSAndrii Nakryiko 	size_t hypot_cnt;
2657d5caef5bSAndrii Nakryiko 	size_t hypot_cap;
2658d5caef5bSAndrii Nakryiko 	/* Various option modifying behavior of algorithm */
2659d5caef5bSAndrii Nakryiko 	struct btf_dedup_opts opts;
2660d5caef5bSAndrii Nakryiko };
2661d5caef5bSAndrii Nakryiko 
2662d5caef5bSAndrii Nakryiko struct btf_str_ptr {
2663d5caef5bSAndrii Nakryiko 	const char *str;
2664d5caef5bSAndrii Nakryiko 	__u32 new_off;
2665d5caef5bSAndrii Nakryiko 	bool used;
2666d5caef5bSAndrii Nakryiko };
2667d5caef5bSAndrii Nakryiko 
2668d5caef5bSAndrii Nakryiko struct btf_str_ptrs {
2669d5caef5bSAndrii Nakryiko 	struct btf_str_ptr *ptrs;
2670d5caef5bSAndrii Nakryiko 	const char *data;
2671d5caef5bSAndrii Nakryiko 	__u32 cnt;
2672d5caef5bSAndrii Nakryiko 	__u32 cap;
2673d5caef5bSAndrii Nakryiko };
2674d5caef5bSAndrii Nakryiko 
26752fc3fc0bSAndrii Nakryiko static long hash_combine(long h, long value)
2676d5caef5bSAndrii Nakryiko {
26772fc3fc0bSAndrii Nakryiko 	return h * 31 + value;
2678d5caef5bSAndrii Nakryiko }
2679d5caef5bSAndrii Nakryiko 
26802fc3fc0bSAndrii Nakryiko #define for_each_dedup_cand(d, node, hash) \
26812fc3fc0bSAndrii Nakryiko 	hashmap__for_each_key_entry(d->dedup_table, node, (void *)hash)
2682d5caef5bSAndrii Nakryiko 
26832fc3fc0bSAndrii Nakryiko static int btf_dedup_table_add(struct btf_dedup *d, long hash, __u32 type_id)
2684d5caef5bSAndrii Nakryiko {
26852fc3fc0bSAndrii Nakryiko 	return hashmap__append(d->dedup_table,
26862fc3fc0bSAndrii Nakryiko 			       (void *)hash, (void *)(long)type_id);
2687d5caef5bSAndrii Nakryiko }
2688d5caef5bSAndrii Nakryiko 
2689d5caef5bSAndrii Nakryiko static int btf_dedup_hypot_map_add(struct btf_dedup *d,
2690d5caef5bSAndrii Nakryiko 				   __u32 from_id, __u32 to_id)
2691d5caef5bSAndrii Nakryiko {
2692d5caef5bSAndrii Nakryiko 	if (d->hypot_cnt == d->hypot_cap) {
2693d5caef5bSAndrii Nakryiko 		__u32 *new_list;
2694d5caef5bSAndrii Nakryiko 
2695fb2426adSMartin KaFai Lau 		d->hypot_cap += max((size_t)16, d->hypot_cap / 2);
2696029258d7SAndrii Nakryiko 		new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32));
2697d5caef5bSAndrii Nakryiko 		if (!new_list)
2698d5caef5bSAndrii Nakryiko 			return -ENOMEM;
2699d5caef5bSAndrii Nakryiko 		d->hypot_list = new_list;
2700d5caef5bSAndrii Nakryiko 	}
2701d5caef5bSAndrii Nakryiko 	d->hypot_list[d->hypot_cnt++] = from_id;
2702d5caef5bSAndrii Nakryiko 	d->hypot_map[from_id] = to_id;
2703d5caef5bSAndrii Nakryiko 	return 0;
2704d5caef5bSAndrii Nakryiko }
2705d5caef5bSAndrii Nakryiko 
2706d5caef5bSAndrii Nakryiko static void btf_dedup_clear_hypot_map(struct btf_dedup *d)
2707d5caef5bSAndrii Nakryiko {
2708d5caef5bSAndrii Nakryiko 	int i;
2709d5caef5bSAndrii Nakryiko 
2710d5caef5bSAndrii Nakryiko 	for (i = 0; i < d->hypot_cnt; i++)
2711d5caef5bSAndrii Nakryiko 		d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID;
2712d5caef5bSAndrii Nakryiko 	d->hypot_cnt = 0;
2713d5caef5bSAndrii Nakryiko }
2714d5caef5bSAndrii Nakryiko 
2715d5caef5bSAndrii Nakryiko static void btf_dedup_free(struct btf_dedup *d)
2716d5caef5bSAndrii Nakryiko {
27172fc3fc0bSAndrii Nakryiko 	hashmap__free(d->dedup_table);
27182fc3fc0bSAndrii Nakryiko 	d->dedup_table = NULL;
2719d5caef5bSAndrii Nakryiko 
2720d5caef5bSAndrii Nakryiko 	free(d->map);
2721d5caef5bSAndrii Nakryiko 	d->map = NULL;
2722d5caef5bSAndrii Nakryiko 
2723d5caef5bSAndrii Nakryiko 	free(d->hypot_map);
2724d5caef5bSAndrii Nakryiko 	d->hypot_map = NULL;
2725d5caef5bSAndrii Nakryiko 
2726d5caef5bSAndrii Nakryiko 	free(d->hypot_list);
2727d5caef5bSAndrii Nakryiko 	d->hypot_list = NULL;
2728d5caef5bSAndrii Nakryiko 
2729d5caef5bSAndrii Nakryiko 	free(d);
2730d5caef5bSAndrii Nakryiko }
2731d5caef5bSAndrii Nakryiko 
27322fc3fc0bSAndrii Nakryiko static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx)
273351edf5f6SAndrii Nakryiko {
27342fc3fc0bSAndrii Nakryiko 	return (size_t)key;
273551edf5f6SAndrii Nakryiko }
273651edf5f6SAndrii Nakryiko 
27372fc3fc0bSAndrii Nakryiko static size_t btf_dedup_collision_hash_fn(const void *key, void *ctx)
27382fc3fc0bSAndrii Nakryiko {
27392fc3fc0bSAndrii Nakryiko 	return 0;
27402fc3fc0bSAndrii Nakryiko }
27412fc3fc0bSAndrii Nakryiko 
27422fc3fc0bSAndrii Nakryiko static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx)
27432fc3fc0bSAndrii Nakryiko {
27442fc3fc0bSAndrii Nakryiko 	return k1 == k2;
27452fc3fc0bSAndrii Nakryiko }
274651edf5f6SAndrii Nakryiko 
2747d5caef5bSAndrii Nakryiko static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
2748d5caef5bSAndrii Nakryiko 				       const struct btf_dedup_opts *opts)
2749d5caef5bSAndrii Nakryiko {
2750d5caef5bSAndrii Nakryiko 	struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup));
27512fc3fc0bSAndrii Nakryiko 	hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn;
2752d5caef5bSAndrii Nakryiko 	int i, err = 0;
2753d5caef5bSAndrii Nakryiko 
2754d5caef5bSAndrii Nakryiko 	if (!d)
2755d5caef5bSAndrii Nakryiko 		return ERR_PTR(-ENOMEM);
2756d5caef5bSAndrii Nakryiko 
275751edf5f6SAndrii Nakryiko 	d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds;
27582fc3fc0bSAndrii Nakryiko 	/* dedup_table_size is now used only to force collisions in tests */
27592fc3fc0bSAndrii Nakryiko 	if (opts && opts->dedup_table_size == 1)
27602fc3fc0bSAndrii Nakryiko 		hash_fn = btf_dedup_collision_hash_fn;
276151edf5f6SAndrii Nakryiko 
2762d5caef5bSAndrii Nakryiko 	d->btf = btf;
2763d5caef5bSAndrii Nakryiko 	d->btf_ext = btf_ext;
2764d5caef5bSAndrii Nakryiko 
27652fc3fc0bSAndrii Nakryiko 	d->dedup_table = hashmap__new(hash_fn, btf_dedup_equal_fn, NULL);
27662fc3fc0bSAndrii Nakryiko 	if (IS_ERR(d->dedup_table)) {
27672fc3fc0bSAndrii Nakryiko 		err = PTR_ERR(d->dedup_table);
27682fc3fc0bSAndrii Nakryiko 		d->dedup_table = NULL;
2769d5caef5bSAndrii Nakryiko 		goto done;
2770d5caef5bSAndrii Nakryiko 	}
2771d5caef5bSAndrii Nakryiko 
2772d5caef5bSAndrii Nakryiko 	d->map = malloc(sizeof(__u32) * (1 + btf->nr_types));
2773d5caef5bSAndrii Nakryiko 	if (!d->map) {
2774d5caef5bSAndrii Nakryiko 		err = -ENOMEM;
2775d5caef5bSAndrii Nakryiko 		goto done;
2776d5caef5bSAndrii Nakryiko 	}
2777d5caef5bSAndrii Nakryiko 	/* special BTF "void" type is made canonical immediately */
2778d5caef5bSAndrii Nakryiko 	d->map[0] = 0;
2779189cf5a4SAndrii Nakryiko 	for (i = 1; i <= btf->nr_types; i++) {
2780740e69c3SAndrii Nakryiko 		struct btf_type *t = btf_type_by_id(d->btf, i);
2781189cf5a4SAndrii Nakryiko 
2782189cf5a4SAndrii Nakryiko 		/* VAR and DATASEC are never deduped and are self-canonical */
2783b03bc685SAndrii Nakryiko 		if (btf_is_var(t) || btf_is_datasec(t))
2784189cf5a4SAndrii Nakryiko 			d->map[i] = i;
2785189cf5a4SAndrii Nakryiko 		else
2786d5caef5bSAndrii Nakryiko 			d->map[i] = BTF_UNPROCESSED_ID;
2787189cf5a4SAndrii Nakryiko 	}
2788d5caef5bSAndrii Nakryiko 
2789d5caef5bSAndrii Nakryiko 	d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types));
2790d5caef5bSAndrii Nakryiko 	if (!d->hypot_map) {
2791d5caef5bSAndrii Nakryiko 		err = -ENOMEM;
2792d5caef5bSAndrii Nakryiko 		goto done;
2793d5caef5bSAndrii Nakryiko 	}
2794d5caef5bSAndrii Nakryiko 	for (i = 0; i <= btf->nr_types; i++)
2795d5caef5bSAndrii Nakryiko 		d->hypot_map[i] = BTF_UNPROCESSED_ID;
2796d5caef5bSAndrii Nakryiko 
2797d5caef5bSAndrii Nakryiko done:
2798d5caef5bSAndrii Nakryiko 	if (err) {
2799d5caef5bSAndrii Nakryiko 		btf_dedup_free(d);
2800d5caef5bSAndrii Nakryiko 		return ERR_PTR(err);
2801d5caef5bSAndrii Nakryiko 	}
2802d5caef5bSAndrii Nakryiko 
2803d5caef5bSAndrii Nakryiko 	return d;
2804d5caef5bSAndrii Nakryiko }
2805d5caef5bSAndrii Nakryiko 
2806d5caef5bSAndrii Nakryiko typedef int (*str_off_fn_t)(__u32 *str_off_ptr, void *ctx);
2807d5caef5bSAndrii Nakryiko 
2808d5caef5bSAndrii Nakryiko /*
2809d5caef5bSAndrii Nakryiko  * Iterate over all possible places in .BTF and .BTF.ext that can reference
2810d5caef5bSAndrii Nakryiko  * string and pass pointer to it to a provided callback `fn`.
2811d5caef5bSAndrii Nakryiko  */
2812d5caef5bSAndrii Nakryiko static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx)
2813d5caef5bSAndrii Nakryiko {
2814d5caef5bSAndrii Nakryiko 	void *line_data_cur, *line_data_end;
2815d5caef5bSAndrii Nakryiko 	int i, j, r, rec_size;
2816d5caef5bSAndrii Nakryiko 	struct btf_type *t;
2817d5caef5bSAndrii Nakryiko 
2818d5caef5bSAndrii Nakryiko 	for (i = 1; i <= d->btf->nr_types; i++) {
2819740e69c3SAndrii Nakryiko 		t = btf_type_by_id(d->btf, i);
2820d5caef5bSAndrii Nakryiko 		r = fn(&t->name_off, ctx);
2821d5caef5bSAndrii Nakryiko 		if (r)
2822d5caef5bSAndrii Nakryiko 			return r;
2823d5caef5bSAndrii Nakryiko 
2824b03bc685SAndrii Nakryiko 		switch (btf_kind(t)) {
2825d5caef5bSAndrii Nakryiko 		case BTF_KIND_STRUCT:
2826d5caef5bSAndrii Nakryiko 		case BTF_KIND_UNION: {
2827b03bc685SAndrii Nakryiko 			struct btf_member *m = btf_members(t);
2828b03bc685SAndrii Nakryiko 			__u16 vlen = btf_vlen(t);
2829d5caef5bSAndrii Nakryiko 
2830d5caef5bSAndrii Nakryiko 			for (j = 0; j < vlen; j++) {
2831d5caef5bSAndrii Nakryiko 				r = fn(&m->name_off, ctx);
2832d5caef5bSAndrii Nakryiko 				if (r)
2833d5caef5bSAndrii Nakryiko 					return r;
2834d5caef5bSAndrii Nakryiko 				m++;
2835d5caef5bSAndrii Nakryiko 			}
2836d5caef5bSAndrii Nakryiko 			break;
2837d5caef5bSAndrii Nakryiko 		}
2838d5caef5bSAndrii Nakryiko 		case BTF_KIND_ENUM: {
2839b03bc685SAndrii Nakryiko 			struct btf_enum *m = btf_enum(t);
2840b03bc685SAndrii Nakryiko 			__u16 vlen = btf_vlen(t);
2841d5caef5bSAndrii Nakryiko 
2842d5caef5bSAndrii Nakryiko 			for (j = 0; j < vlen; j++) {
2843d5caef5bSAndrii Nakryiko 				r = fn(&m->name_off, ctx);
2844d5caef5bSAndrii Nakryiko 				if (r)
2845d5caef5bSAndrii Nakryiko 					return r;
2846d5caef5bSAndrii Nakryiko 				m++;
2847d5caef5bSAndrii Nakryiko 			}
2848d5caef5bSAndrii Nakryiko 			break;
2849d5caef5bSAndrii Nakryiko 		}
2850d5caef5bSAndrii Nakryiko 		case BTF_KIND_FUNC_PROTO: {
2851b03bc685SAndrii Nakryiko 			struct btf_param *m = btf_params(t);
2852b03bc685SAndrii Nakryiko 			__u16 vlen = btf_vlen(t);
2853d5caef5bSAndrii Nakryiko 
2854d5caef5bSAndrii Nakryiko 			for (j = 0; j < vlen; j++) {
2855d5caef5bSAndrii Nakryiko 				r = fn(&m->name_off, ctx);
2856d5caef5bSAndrii Nakryiko 				if (r)
2857d5caef5bSAndrii Nakryiko 					return r;
2858d5caef5bSAndrii Nakryiko 				m++;
2859d5caef5bSAndrii Nakryiko 			}
2860d5caef5bSAndrii Nakryiko 			break;
2861d5caef5bSAndrii Nakryiko 		}
2862d5caef5bSAndrii Nakryiko 		default:
2863d5caef5bSAndrii Nakryiko 			break;
2864d5caef5bSAndrii Nakryiko 		}
2865d5caef5bSAndrii Nakryiko 	}
2866d5caef5bSAndrii Nakryiko 
2867d5caef5bSAndrii Nakryiko 	if (!d->btf_ext)
2868d5caef5bSAndrii Nakryiko 		return 0;
2869d5caef5bSAndrii Nakryiko 
2870d5caef5bSAndrii Nakryiko 	line_data_cur = d->btf_ext->line_info.info;
2871d5caef5bSAndrii Nakryiko 	line_data_end = d->btf_ext->line_info.info + d->btf_ext->line_info.len;
2872d5caef5bSAndrii Nakryiko 	rec_size = d->btf_ext->line_info.rec_size;
2873d5caef5bSAndrii Nakryiko 
2874d5caef5bSAndrii Nakryiko 	while (line_data_cur < line_data_end) {
2875d5caef5bSAndrii Nakryiko 		struct btf_ext_info_sec *sec = line_data_cur;
2876d5caef5bSAndrii Nakryiko 		struct bpf_line_info_min *line_info;
2877d5caef5bSAndrii Nakryiko 		__u32 num_info = sec->num_info;
2878d5caef5bSAndrii Nakryiko 
2879d5caef5bSAndrii Nakryiko 		r = fn(&sec->sec_name_off, ctx);
2880d5caef5bSAndrii Nakryiko 		if (r)
2881d5caef5bSAndrii Nakryiko 			return r;
2882d5caef5bSAndrii Nakryiko 
2883d5caef5bSAndrii Nakryiko 		line_data_cur += sizeof(struct btf_ext_info_sec);
2884d5caef5bSAndrii Nakryiko 		for (i = 0; i < num_info; i++) {
2885d5caef5bSAndrii Nakryiko 			line_info = line_data_cur;
2886d5caef5bSAndrii Nakryiko 			r = fn(&line_info->file_name_off, ctx);
2887d5caef5bSAndrii Nakryiko 			if (r)
2888d5caef5bSAndrii Nakryiko 				return r;
2889d5caef5bSAndrii Nakryiko 			r = fn(&line_info->line_off, ctx);
2890d5caef5bSAndrii Nakryiko 			if (r)
2891d5caef5bSAndrii Nakryiko 				return r;
2892d5caef5bSAndrii Nakryiko 			line_data_cur += rec_size;
2893d5caef5bSAndrii Nakryiko 		}
2894d5caef5bSAndrii Nakryiko 	}
2895d5caef5bSAndrii Nakryiko 
2896d5caef5bSAndrii Nakryiko 	return 0;
2897d5caef5bSAndrii Nakryiko }
2898d5caef5bSAndrii Nakryiko 
2899d5caef5bSAndrii Nakryiko static int str_sort_by_content(const void *a1, const void *a2)
2900d5caef5bSAndrii Nakryiko {
2901d5caef5bSAndrii Nakryiko 	const struct btf_str_ptr *p1 = a1;
2902d5caef5bSAndrii Nakryiko 	const struct btf_str_ptr *p2 = a2;
2903d5caef5bSAndrii Nakryiko 
2904d5caef5bSAndrii Nakryiko 	return strcmp(p1->str, p2->str);
2905d5caef5bSAndrii Nakryiko }
2906d5caef5bSAndrii Nakryiko 
2907d5caef5bSAndrii Nakryiko static int str_sort_by_offset(const void *a1, const void *a2)
2908d5caef5bSAndrii Nakryiko {
2909d5caef5bSAndrii Nakryiko 	const struct btf_str_ptr *p1 = a1;
2910d5caef5bSAndrii Nakryiko 	const struct btf_str_ptr *p2 = a2;
2911d5caef5bSAndrii Nakryiko 
2912d5caef5bSAndrii Nakryiko 	if (p1->str != p2->str)
2913d5caef5bSAndrii Nakryiko 		return p1->str < p2->str ? -1 : 1;
2914d5caef5bSAndrii Nakryiko 	return 0;
2915d5caef5bSAndrii Nakryiko }
2916d5caef5bSAndrii Nakryiko 
2917d5caef5bSAndrii Nakryiko static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem)
2918d5caef5bSAndrii Nakryiko {
2919d5caef5bSAndrii Nakryiko 	const struct btf_str_ptr *p = pelem;
2920d5caef5bSAndrii Nakryiko 
2921d5caef5bSAndrii Nakryiko 	if (str_ptr != p->str)
2922d5caef5bSAndrii Nakryiko 		return (const char *)str_ptr < p->str ? -1 : 1;
2923d5caef5bSAndrii Nakryiko 	return 0;
2924d5caef5bSAndrii Nakryiko }
2925d5caef5bSAndrii Nakryiko 
2926d5caef5bSAndrii Nakryiko static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx)
2927d5caef5bSAndrii Nakryiko {
2928d5caef5bSAndrii Nakryiko 	struct btf_str_ptrs *strs;
2929d5caef5bSAndrii Nakryiko 	struct btf_str_ptr *s;
2930d5caef5bSAndrii Nakryiko 
2931d5caef5bSAndrii Nakryiko 	if (*str_off_ptr == 0)
2932d5caef5bSAndrii Nakryiko 		return 0;
2933d5caef5bSAndrii Nakryiko 
2934d5caef5bSAndrii Nakryiko 	strs = ctx;
2935d5caef5bSAndrii Nakryiko 	s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
2936d5caef5bSAndrii Nakryiko 		    sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
2937d5caef5bSAndrii Nakryiko 	if (!s)
2938d5caef5bSAndrii Nakryiko 		return -EINVAL;
2939d5caef5bSAndrii Nakryiko 	s->used = true;
2940d5caef5bSAndrii Nakryiko 	return 0;
2941d5caef5bSAndrii Nakryiko }
2942d5caef5bSAndrii Nakryiko 
2943d5caef5bSAndrii Nakryiko static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx)
2944d5caef5bSAndrii Nakryiko {
2945d5caef5bSAndrii Nakryiko 	struct btf_str_ptrs *strs;
2946d5caef5bSAndrii Nakryiko 	struct btf_str_ptr *s;
2947d5caef5bSAndrii Nakryiko 
2948d5caef5bSAndrii Nakryiko 	if (*str_off_ptr == 0)
2949d5caef5bSAndrii Nakryiko 		return 0;
2950d5caef5bSAndrii Nakryiko 
2951d5caef5bSAndrii Nakryiko 	strs = ctx;
2952d5caef5bSAndrii Nakryiko 	s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
2953d5caef5bSAndrii Nakryiko 		    sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
2954d5caef5bSAndrii Nakryiko 	if (!s)
2955d5caef5bSAndrii Nakryiko 		return -EINVAL;
2956d5caef5bSAndrii Nakryiko 	*str_off_ptr = s->new_off;
2957d5caef5bSAndrii Nakryiko 	return 0;
2958d5caef5bSAndrii Nakryiko }
2959d5caef5bSAndrii Nakryiko 
2960d5caef5bSAndrii Nakryiko /*
2961d5caef5bSAndrii Nakryiko  * Dedup string and filter out those that are not referenced from either .BTF
2962d5caef5bSAndrii Nakryiko  * or .BTF.ext (if provided) sections.
2963d5caef5bSAndrii Nakryiko  *
2964d5caef5bSAndrii Nakryiko  * This is done by building index of all strings in BTF's string section,
2965d5caef5bSAndrii Nakryiko  * then iterating over all entities that can reference strings (e.g., type
2966d5caef5bSAndrii Nakryiko  * names, struct field names, .BTF.ext line info, etc) and marking corresponding
2967d5caef5bSAndrii Nakryiko  * strings as used. After that all used strings are deduped and compacted into
2968d5caef5bSAndrii Nakryiko  * sequential blob of memory and new offsets are calculated. Then all the string
2969d5caef5bSAndrii Nakryiko  * references are iterated again and rewritten using new offsets.
2970d5caef5bSAndrii Nakryiko  */
2971d5caef5bSAndrii Nakryiko static int btf_dedup_strings(struct btf_dedup *d)
2972d5caef5bSAndrii Nakryiko {
2973b8604247SAndrii Nakryiko 	char *start = d->btf->strs_data;
2974d5caef5bSAndrii Nakryiko 	char *end = start + d->btf->hdr->str_len;
2975d5caef5bSAndrii Nakryiko 	char *p = start, *tmp_strs = NULL;
2976d5caef5bSAndrii Nakryiko 	struct btf_str_ptrs strs = {
2977d5caef5bSAndrii Nakryiko 		.cnt = 0,
2978d5caef5bSAndrii Nakryiko 		.cap = 0,
2979d5caef5bSAndrii Nakryiko 		.ptrs = NULL,
2980d5caef5bSAndrii Nakryiko 		.data = start,
2981d5caef5bSAndrii Nakryiko 	};
2982d5caef5bSAndrii Nakryiko 	int i, j, err = 0, grp_idx;
2983d5caef5bSAndrii Nakryiko 	bool grp_used;
2984d5caef5bSAndrii Nakryiko 
2985919d2b1dSAndrii Nakryiko 	if (d->btf->strs_deduped)
2986919d2b1dSAndrii Nakryiko 		return 0;
2987919d2b1dSAndrii Nakryiko 
2988d5caef5bSAndrii Nakryiko 	/* build index of all strings */
2989d5caef5bSAndrii Nakryiko 	while (p < end) {
2990d5caef5bSAndrii Nakryiko 		if (strs.cnt + 1 > strs.cap) {
2991d5caef5bSAndrii Nakryiko 			struct btf_str_ptr *new_ptrs;
2992d5caef5bSAndrii Nakryiko 
2993fb2426adSMartin KaFai Lau 			strs.cap += max(strs.cnt / 2, 16U);
2994029258d7SAndrii Nakryiko 			new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0]));
2995d5caef5bSAndrii Nakryiko 			if (!new_ptrs) {
2996d5caef5bSAndrii Nakryiko 				err = -ENOMEM;
2997d5caef5bSAndrii Nakryiko 				goto done;
2998d5caef5bSAndrii Nakryiko 			}
2999d5caef5bSAndrii Nakryiko 			strs.ptrs = new_ptrs;
3000d5caef5bSAndrii Nakryiko 		}
3001d5caef5bSAndrii Nakryiko 
3002d5caef5bSAndrii Nakryiko 		strs.ptrs[strs.cnt].str = p;
3003d5caef5bSAndrii Nakryiko 		strs.ptrs[strs.cnt].used = false;
3004d5caef5bSAndrii Nakryiko 
3005d5caef5bSAndrii Nakryiko 		p += strlen(p) + 1;
3006d5caef5bSAndrii Nakryiko 		strs.cnt++;
3007d5caef5bSAndrii Nakryiko 	}
3008d5caef5bSAndrii Nakryiko 
3009d5caef5bSAndrii Nakryiko 	/* temporary storage for deduplicated strings */
3010d5caef5bSAndrii Nakryiko 	tmp_strs = malloc(d->btf->hdr->str_len);
3011d5caef5bSAndrii Nakryiko 	if (!tmp_strs) {
3012d5caef5bSAndrii Nakryiko 		err = -ENOMEM;
3013d5caef5bSAndrii Nakryiko 		goto done;
3014d5caef5bSAndrii Nakryiko 	}
3015d5caef5bSAndrii Nakryiko 
3016d5caef5bSAndrii Nakryiko 	/* mark all used strings */
3017d5caef5bSAndrii Nakryiko 	strs.ptrs[0].used = true;
3018d5caef5bSAndrii Nakryiko 	err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs);
3019d5caef5bSAndrii Nakryiko 	if (err)
3020d5caef5bSAndrii Nakryiko 		goto done;
3021d5caef5bSAndrii Nakryiko 
3022d5caef5bSAndrii Nakryiko 	/* sort strings by context, so that we can identify duplicates */
3023d5caef5bSAndrii Nakryiko 	qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content);
3024d5caef5bSAndrii Nakryiko 
3025d5caef5bSAndrii Nakryiko 	/*
3026d5caef5bSAndrii Nakryiko 	 * iterate groups of equal strings and if any instance in a group was
3027d5caef5bSAndrii Nakryiko 	 * referenced, emit single instance and remember new offset
3028d5caef5bSAndrii Nakryiko 	 */
3029d5caef5bSAndrii Nakryiko 	p = tmp_strs;
3030d5caef5bSAndrii Nakryiko 	grp_idx = 0;
3031d5caef5bSAndrii Nakryiko 	grp_used = strs.ptrs[0].used;
3032d5caef5bSAndrii Nakryiko 	/* iterate past end to avoid code duplication after loop */
3033d5caef5bSAndrii Nakryiko 	for (i = 1; i <= strs.cnt; i++) {
3034d5caef5bSAndrii Nakryiko 		/*
3035d5caef5bSAndrii Nakryiko 		 * when i == strs.cnt, we want to skip string comparison and go
3036d5caef5bSAndrii Nakryiko 		 * straight to handling last group of strings (otherwise we'd
3037d5caef5bSAndrii Nakryiko 		 * need to handle last group after the loop w/ duplicated code)
3038d5caef5bSAndrii Nakryiko 		 */
3039d5caef5bSAndrii Nakryiko 		if (i < strs.cnt &&
3040d5caef5bSAndrii Nakryiko 		    !strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) {
3041d5caef5bSAndrii Nakryiko 			grp_used = grp_used || strs.ptrs[i].used;
3042d5caef5bSAndrii Nakryiko 			continue;
3043d5caef5bSAndrii Nakryiko 		}
3044d5caef5bSAndrii Nakryiko 
3045d5caef5bSAndrii Nakryiko 		/*
3046d5caef5bSAndrii Nakryiko 		 * this check would have been required after the loop to handle
3047d5caef5bSAndrii Nakryiko 		 * last group of strings, but due to <= condition in a loop
3048d5caef5bSAndrii Nakryiko 		 * we avoid that duplication
3049d5caef5bSAndrii Nakryiko 		 */
3050d5caef5bSAndrii Nakryiko 		if (grp_used) {
3051d5caef5bSAndrii Nakryiko 			int new_off = p - tmp_strs;
3052d5caef5bSAndrii Nakryiko 			__u32 len = strlen(strs.ptrs[grp_idx].str);
3053d5caef5bSAndrii Nakryiko 
3054d5caef5bSAndrii Nakryiko 			memmove(p, strs.ptrs[grp_idx].str, len + 1);
3055d5caef5bSAndrii Nakryiko 			for (j = grp_idx; j < i; j++)
3056d5caef5bSAndrii Nakryiko 				strs.ptrs[j].new_off = new_off;
3057d5caef5bSAndrii Nakryiko 			p += len + 1;
3058d5caef5bSAndrii Nakryiko 		}
3059d5caef5bSAndrii Nakryiko 
3060d5caef5bSAndrii Nakryiko 		if (i < strs.cnt) {
3061d5caef5bSAndrii Nakryiko 			grp_idx = i;
3062d5caef5bSAndrii Nakryiko 			grp_used = strs.ptrs[i].used;
3063d5caef5bSAndrii Nakryiko 		}
3064d5caef5bSAndrii Nakryiko 	}
3065d5caef5bSAndrii Nakryiko 
3066d5caef5bSAndrii Nakryiko 	/* replace original strings with deduped ones */
3067d5caef5bSAndrii Nakryiko 	d->btf->hdr->str_len = p - tmp_strs;
3068d5caef5bSAndrii Nakryiko 	memmove(start, tmp_strs, d->btf->hdr->str_len);
3069d5caef5bSAndrii Nakryiko 	end = start + d->btf->hdr->str_len;
3070d5caef5bSAndrii Nakryiko 
3071d5caef5bSAndrii Nakryiko 	/* restore original order for further binary search lookups */
3072d5caef5bSAndrii Nakryiko 	qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset);
3073d5caef5bSAndrii Nakryiko 
3074d5caef5bSAndrii Nakryiko 	/* remap string offsets */
3075d5caef5bSAndrii Nakryiko 	err = btf_for_each_str_off(d, btf_str_remap_offset, &strs);
3076d5caef5bSAndrii Nakryiko 	if (err)
3077d5caef5bSAndrii Nakryiko 		goto done;
3078d5caef5bSAndrii Nakryiko 
3079d5caef5bSAndrii Nakryiko 	d->btf->hdr->str_len = end - start;
3080919d2b1dSAndrii Nakryiko 	d->btf->strs_deduped = true;
3081d5caef5bSAndrii Nakryiko 
3082d5caef5bSAndrii Nakryiko done:
3083d5caef5bSAndrii Nakryiko 	free(tmp_strs);
3084d5caef5bSAndrii Nakryiko 	free(strs.ptrs);
3085d5caef5bSAndrii Nakryiko 	return err;
3086d5caef5bSAndrii Nakryiko }
3087d5caef5bSAndrii Nakryiko 
30882fc3fc0bSAndrii Nakryiko static long btf_hash_common(struct btf_type *t)
3089d5caef5bSAndrii Nakryiko {
30902fc3fc0bSAndrii Nakryiko 	long h;
3091d5caef5bSAndrii Nakryiko 
3092d5caef5bSAndrii Nakryiko 	h = hash_combine(0, t->name_off);
3093d5caef5bSAndrii Nakryiko 	h = hash_combine(h, t->info);
3094d5caef5bSAndrii Nakryiko 	h = hash_combine(h, t->size);
3095d5caef5bSAndrii Nakryiko 	return h;
3096d5caef5bSAndrii Nakryiko }
3097d5caef5bSAndrii Nakryiko 
3098d5caef5bSAndrii Nakryiko static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2)
3099d5caef5bSAndrii Nakryiko {
3100d5caef5bSAndrii Nakryiko 	return t1->name_off == t2->name_off &&
3101d5caef5bSAndrii Nakryiko 	       t1->info == t2->info &&
3102d5caef5bSAndrii Nakryiko 	       t1->size == t2->size;
3103d5caef5bSAndrii Nakryiko }
3104d5caef5bSAndrii Nakryiko 
3105d5caef5bSAndrii Nakryiko /* Calculate type signature hash of INT. */
31062fc3fc0bSAndrii Nakryiko static long btf_hash_int(struct btf_type *t)
3107d5caef5bSAndrii Nakryiko {
3108d5caef5bSAndrii Nakryiko 	__u32 info = *(__u32 *)(t + 1);
31092fc3fc0bSAndrii Nakryiko 	long h;
3110d5caef5bSAndrii Nakryiko 
3111d5caef5bSAndrii Nakryiko 	h = btf_hash_common(t);
3112d5caef5bSAndrii Nakryiko 	h = hash_combine(h, info);
3113d5caef5bSAndrii Nakryiko 	return h;
3114d5caef5bSAndrii Nakryiko }
3115d5caef5bSAndrii Nakryiko 
3116d5caef5bSAndrii Nakryiko /* Check structural equality of two INTs. */
3117d5caef5bSAndrii Nakryiko static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2)
3118d5caef5bSAndrii Nakryiko {
3119d5caef5bSAndrii Nakryiko 	__u32 info1, info2;
3120d5caef5bSAndrii Nakryiko 
3121d5caef5bSAndrii Nakryiko 	if (!btf_equal_common(t1, t2))
3122d5caef5bSAndrii Nakryiko 		return false;
3123d5caef5bSAndrii Nakryiko 	info1 = *(__u32 *)(t1 + 1);
3124d5caef5bSAndrii Nakryiko 	info2 = *(__u32 *)(t2 + 1);
3125d5caef5bSAndrii Nakryiko 	return info1 == info2;
3126d5caef5bSAndrii Nakryiko }
3127d5caef5bSAndrii Nakryiko 
3128d5caef5bSAndrii Nakryiko /* Calculate type signature hash of ENUM. */
31292fc3fc0bSAndrii Nakryiko static long btf_hash_enum(struct btf_type *t)
3130d5caef5bSAndrii Nakryiko {
31312fc3fc0bSAndrii Nakryiko 	long h;
3132d5caef5bSAndrii Nakryiko 
31339768095bSAndrii Nakryiko 	/* don't hash vlen and enum members to support enum fwd resolving */
31349768095bSAndrii Nakryiko 	h = hash_combine(0, t->name_off);
31359768095bSAndrii Nakryiko 	h = hash_combine(h, t->info & ~0xffff);
31369768095bSAndrii Nakryiko 	h = hash_combine(h, t->size);
3137d5caef5bSAndrii Nakryiko 	return h;
3138d5caef5bSAndrii Nakryiko }
3139d5caef5bSAndrii Nakryiko 
3140d5caef5bSAndrii Nakryiko /* Check structural equality of two ENUMs. */
3141d5caef5bSAndrii Nakryiko static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
3142d5caef5bSAndrii Nakryiko {
3143b03bc685SAndrii Nakryiko 	const struct btf_enum *m1, *m2;
3144d5caef5bSAndrii Nakryiko 	__u16 vlen;
3145d5caef5bSAndrii Nakryiko 	int i;
3146d5caef5bSAndrii Nakryiko 
3147d5caef5bSAndrii Nakryiko 	if (!btf_equal_common(t1, t2))
3148d5caef5bSAndrii Nakryiko 		return false;
3149d5caef5bSAndrii Nakryiko 
3150b03bc685SAndrii Nakryiko 	vlen = btf_vlen(t1);
3151b03bc685SAndrii Nakryiko 	m1 = btf_enum(t1);
3152b03bc685SAndrii Nakryiko 	m2 = btf_enum(t2);
3153d5caef5bSAndrii Nakryiko 	for (i = 0; i < vlen; i++) {
3154d5caef5bSAndrii Nakryiko 		if (m1->name_off != m2->name_off || m1->val != m2->val)
3155d5caef5bSAndrii Nakryiko 			return false;
3156d5caef5bSAndrii Nakryiko 		m1++;
3157d5caef5bSAndrii Nakryiko 		m2++;
3158d5caef5bSAndrii Nakryiko 	}
3159d5caef5bSAndrii Nakryiko 	return true;
3160d5caef5bSAndrii Nakryiko }
3161d5caef5bSAndrii Nakryiko 
31629768095bSAndrii Nakryiko static inline bool btf_is_enum_fwd(struct btf_type *t)
31639768095bSAndrii Nakryiko {
3164b03bc685SAndrii Nakryiko 	return btf_is_enum(t) && btf_vlen(t) == 0;
31659768095bSAndrii Nakryiko }
31669768095bSAndrii Nakryiko 
31679768095bSAndrii Nakryiko static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
31689768095bSAndrii Nakryiko {
31699768095bSAndrii Nakryiko 	if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
31709768095bSAndrii Nakryiko 		return btf_equal_enum(t1, t2);
31719768095bSAndrii Nakryiko 	/* ignore vlen when comparing */
31729768095bSAndrii Nakryiko 	return t1->name_off == t2->name_off &&
31739768095bSAndrii Nakryiko 	       (t1->info & ~0xffff) == (t2->info & ~0xffff) &&
31749768095bSAndrii Nakryiko 	       t1->size == t2->size;
31759768095bSAndrii Nakryiko }
31769768095bSAndrii Nakryiko 
3177d5caef5bSAndrii Nakryiko /*
3178d5caef5bSAndrii Nakryiko  * Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs,
3179d5caef5bSAndrii Nakryiko  * as referenced type IDs equivalence is established separately during type
3180d5caef5bSAndrii Nakryiko  * graph equivalence check algorithm.
3181d5caef5bSAndrii Nakryiko  */
31822fc3fc0bSAndrii Nakryiko static long btf_hash_struct(struct btf_type *t)
3183d5caef5bSAndrii Nakryiko {
3184b03bc685SAndrii Nakryiko 	const struct btf_member *member = btf_members(t);
3185b03bc685SAndrii Nakryiko 	__u32 vlen = btf_vlen(t);
31862fc3fc0bSAndrii Nakryiko 	long h = btf_hash_common(t);
3187d5caef5bSAndrii Nakryiko 	int i;
3188d5caef5bSAndrii Nakryiko 
3189d5caef5bSAndrii Nakryiko 	for (i = 0; i < vlen; i++) {
3190d5caef5bSAndrii Nakryiko 		h = hash_combine(h, member->name_off);
3191d5caef5bSAndrii Nakryiko 		h = hash_combine(h, member->offset);
3192d5caef5bSAndrii Nakryiko 		/* no hashing of referenced type ID, it can be unresolved yet */
3193d5caef5bSAndrii Nakryiko 		member++;
3194d5caef5bSAndrii Nakryiko 	}
3195d5caef5bSAndrii Nakryiko 	return h;
3196d5caef5bSAndrii Nakryiko }
3197d5caef5bSAndrii Nakryiko 
3198d5caef5bSAndrii Nakryiko /*
3199d5caef5bSAndrii Nakryiko  * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
3200d5caef5bSAndrii Nakryiko  * IDs. This check is performed during type graph equivalence check and
3201d5caef5bSAndrii Nakryiko  * referenced types equivalence is checked separately.
3202d5caef5bSAndrii Nakryiko  */
320391097fbeSAndrii Nakryiko static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2)
3204d5caef5bSAndrii Nakryiko {
3205b03bc685SAndrii Nakryiko 	const struct btf_member *m1, *m2;
3206d5caef5bSAndrii Nakryiko 	__u16 vlen;
3207d5caef5bSAndrii Nakryiko 	int i;
3208d5caef5bSAndrii Nakryiko 
3209d5caef5bSAndrii Nakryiko 	if (!btf_equal_common(t1, t2))
3210d5caef5bSAndrii Nakryiko 		return false;
3211d5caef5bSAndrii Nakryiko 
3212b03bc685SAndrii Nakryiko 	vlen = btf_vlen(t1);
3213b03bc685SAndrii Nakryiko 	m1 = btf_members(t1);
3214b03bc685SAndrii Nakryiko 	m2 = btf_members(t2);
3215d5caef5bSAndrii Nakryiko 	for (i = 0; i < vlen; i++) {
3216d5caef5bSAndrii Nakryiko 		if (m1->name_off != m2->name_off || m1->offset != m2->offset)
3217d5caef5bSAndrii Nakryiko 			return false;
3218d5caef5bSAndrii Nakryiko 		m1++;
3219d5caef5bSAndrii Nakryiko 		m2++;
3220d5caef5bSAndrii Nakryiko 	}
3221d5caef5bSAndrii Nakryiko 	return true;
3222d5caef5bSAndrii Nakryiko }
3223d5caef5bSAndrii Nakryiko 
3224d5caef5bSAndrii Nakryiko /*
3225d5caef5bSAndrii Nakryiko  * Calculate type signature hash of ARRAY, including referenced type IDs,
3226d5caef5bSAndrii Nakryiko  * under assumption that they were already resolved to canonical type IDs and
3227d5caef5bSAndrii Nakryiko  * are not going to change.
3228d5caef5bSAndrii Nakryiko  */
32292fc3fc0bSAndrii Nakryiko static long btf_hash_array(struct btf_type *t)
3230d5caef5bSAndrii Nakryiko {
3231b03bc685SAndrii Nakryiko 	const struct btf_array *info = btf_array(t);
32322fc3fc0bSAndrii Nakryiko 	long h = btf_hash_common(t);
3233d5caef5bSAndrii Nakryiko 
3234d5caef5bSAndrii Nakryiko 	h = hash_combine(h, info->type);
3235d5caef5bSAndrii Nakryiko 	h = hash_combine(h, info->index_type);
3236d5caef5bSAndrii Nakryiko 	h = hash_combine(h, info->nelems);
3237d5caef5bSAndrii Nakryiko 	return h;
3238d5caef5bSAndrii Nakryiko }
3239d5caef5bSAndrii Nakryiko 
3240d5caef5bSAndrii Nakryiko /*
3241d5caef5bSAndrii Nakryiko  * Check exact equality of two ARRAYs, taking into account referenced
3242d5caef5bSAndrii Nakryiko  * type IDs, under assumption that they were already resolved to canonical
3243d5caef5bSAndrii Nakryiko  * type IDs and are not going to change.
3244d5caef5bSAndrii Nakryiko  * This function is called during reference types deduplication to compare
3245d5caef5bSAndrii Nakryiko  * ARRAY to potential canonical representative.
3246d5caef5bSAndrii Nakryiko  */
3247d5caef5bSAndrii Nakryiko static bool btf_equal_array(struct btf_type *t1, struct btf_type *t2)
3248d5caef5bSAndrii Nakryiko {
3249b03bc685SAndrii Nakryiko 	const struct btf_array *info1, *info2;
3250d5caef5bSAndrii Nakryiko 
3251d5caef5bSAndrii Nakryiko 	if (!btf_equal_common(t1, t2))
3252d5caef5bSAndrii Nakryiko 		return false;
3253d5caef5bSAndrii Nakryiko 
3254b03bc685SAndrii Nakryiko 	info1 = btf_array(t1);
3255b03bc685SAndrii Nakryiko 	info2 = btf_array(t2);
3256d5caef5bSAndrii Nakryiko 	return info1->type == info2->type &&
3257d5caef5bSAndrii Nakryiko 	       info1->index_type == info2->index_type &&
3258d5caef5bSAndrii Nakryiko 	       info1->nelems == info2->nelems;
3259d5caef5bSAndrii Nakryiko }
3260d5caef5bSAndrii Nakryiko 
3261d5caef5bSAndrii Nakryiko /*
3262d5caef5bSAndrii Nakryiko  * Check structural compatibility of two ARRAYs, ignoring referenced type
3263d5caef5bSAndrii Nakryiko  * IDs. This check is performed during type graph equivalence check and
3264d5caef5bSAndrii Nakryiko  * referenced types equivalence is checked separately.
3265d5caef5bSAndrii Nakryiko  */
3266d5caef5bSAndrii Nakryiko static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2)
3267d5caef5bSAndrii Nakryiko {
3268d5caef5bSAndrii Nakryiko 	if (!btf_equal_common(t1, t2))
3269d5caef5bSAndrii Nakryiko 		return false;
3270d5caef5bSAndrii Nakryiko 
3271b03bc685SAndrii Nakryiko 	return btf_array(t1)->nelems == btf_array(t2)->nelems;
3272d5caef5bSAndrii Nakryiko }
3273d5caef5bSAndrii Nakryiko 
3274d5caef5bSAndrii Nakryiko /*
3275d5caef5bSAndrii Nakryiko  * Calculate type signature hash of FUNC_PROTO, including referenced type IDs,
3276d5caef5bSAndrii Nakryiko  * under assumption that they were already resolved to canonical type IDs and
3277d5caef5bSAndrii Nakryiko  * are not going to change.
3278d5caef5bSAndrii Nakryiko  */
32792fc3fc0bSAndrii Nakryiko static long btf_hash_fnproto(struct btf_type *t)
3280d5caef5bSAndrii Nakryiko {
3281b03bc685SAndrii Nakryiko 	const struct btf_param *member = btf_params(t);
3282b03bc685SAndrii Nakryiko 	__u16 vlen = btf_vlen(t);
32832fc3fc0bSAndrii Nakryiko 	long h = btf_hash_common(t);
3284d5caef5bSAndrii Nakryiko 	int i;
3285d5caef5bSAndrii Nakryiko 
3286d5caef5bSAndrii Nakryiko 	for (i = 0; i < vlen; i++) {
3287d5caef5bSAndrii Nakryiko 		h = hash_combine(h, member->name_off);
3288d5caef5bSAndrii Nakryiko 		h = hash_combine(h, member->type);
3289d5caef5bSAndrii Nakryiko 		member++;
3290d5caef5bSAndrii Nakryiko 	}
3291d5caef5bSAndrii Nakryiko 	return h;
3292d5caef5bSAndrii Nakryiko }
3293d5caef5bSAndrii Nakryiko 
3294d5caef5bSAndrii Nakryiko /*
3295d5caef5bSAndrii Nakryiko  * Check exact equality of two FUNC_PROTOs, taking into account referenced
3296d5caef5bSAndrii Nakryiko  * type IDs, under assumption that they were already resolved to canonical
3297d5caef5bSAndrii Nakryiko  * type IDs and are not going to change.
3298d5caef5bSAndrii Nakryiko  * This function is called during reference types deduplication to compare
3299d5caef5bSAndrii Nakryiko  * FUNC_PROTO to potential canonical representative.
3300d5caef5bSAndrii Nakryiko  */
33012fc3fc0bSAndrii Nakryiko static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2)
3302d5caef5bSAndrii Nakryiko {
3303b03bc685SAndrii Nakryiko 	const struct btf_param *m1, *m2;
3304d5caef5bSAndrii Nakryiko 	__u16 vlen;
3305d5caef5bSAndrii Nakryiko 	int i;
3306d5caef5bSAndrii Nakryiko 
3307d5caef5bSAndrii Nakryiko 	if (!btf_equal_common(t1, t2))
3308d5caef5bSAndrii Nakryiko 		return false;
3309d5caef5bSAndrii Nakryiko 
3310b03bc685SAndrii Nakryiko 	vlen = btf_vlen(t1);
3311b03bc685SAndrii Nakryiko 	m1 = btf_params(t1);
3312b03bc685SAndrii Nakryiko 	m2 = btf_params(t2);
3313d5caef5bSAndrii Nakryiko 	for (i = 0; i < vlen; i++) {
3314d5caef5bSAndrii Nakryiko 		if (m1->name_off != m2->name_off || m1->type != m2->type)
3315d5caef5bSAndrii Nakryiko 			return false;
3316d5caef5bSAndrii Nakryiko 		m1++;
3317d5caef5bSAndrii Nakryiko 		m2++;
3318d5caef5bSAndrii Nakryiko 	}
3319d5caef5bSAndrii Nakryiko 	return true;
3320d5caef5bSAndrii Nakryiko }
3321d5caef5bSAndrii Nakryiko 
3322d5caef5bSAndrii Nakryiko /*
3323d5caef5bSAndrii Nakryiko  * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
3324d5caef5bSAndrii Nakryiko  * IDs. This check is performed during type graph equivalence check and
3325d5caef5bSAndrii Nakryiko  * referenced types equivalence is checked separately.
3326d5caef5bSAndrii Nakryiko  */
33272fc3fc0bSAndrii Nakryiko static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2)
3328d5caef5bSAndrii Nakryiko {
3329b03bc685SAndrii Nakryiko 	const struct btf_param *m1, *m2;
3330d5caef5bSAndrii Nakryiko 	__u16 vlen;
3331d5caef5bSAndrii Nakryiko 	int i;
3332d5caef5bSAndrii Nakryiko 
3333d5caef5bSAndrii Nakryiko 	/* skip return type ID */
3334d5caef5bSAndrii Nakryiko 	if (t1->name_off != t2->name_off || t1->info != t2->info)
3335d5caef5bSAndrii Nakryiko 		return false;
3336d5caef5bSAndrii Nakryiko 
3337b03bc685SAndrii Nakryiko 	vlen = btf_vlen(t1);
3338b03bc685SAndrii Nakryiko 	m1 = btf_params(t1);
3339b03bc685SAndrii Nakryiko 	m2 = btf_params(t2);
3340d5caef5bSAndrii Nakryiko 	for (i = 0; i < vlen; i++) {
3341d5caef5bSAndrii Nakryiko 		if (m1->name_off != m2->name_off)
3342d5caef5bSAndrii Nakryiko 			return false;
3343d5caef5bSAndrii Nakryiko 		m1++;
3344d5caef5bSAndrii Nakryiko 		m2++;
3345d5caef5bSAndrii Nakryiko 	}
3346d5caef5bSAndrii Nakryiko 	return true;
3347d5caef5bSAndrii Nakryiko }
3348d5caef5bSAndrii Nakryiko 
3349d5caef5bSAndrii Nakryiko /*
3350d5caef5bSAndrii Nakryiko  * Deduplicate primitive types, that can't reference other types, by calculating
3351d5caef5bSAndrii Nakryiko  * their type signature hash and comparing them with any possible canonical
3352d5caef5bSAndrii Nakryiko  * candidate. If no canonical candidate matches, type itself is marked as
3353d5caef5bSAndrii Nakryiko  * canonical and is added into `btf_dedup->dedup_table` as another candidate.
3354d5caef5bSAndrii Nakryiko  */
3355d5caef5bSAndrii Nakryiko static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
3356d5caef5bSAndrii Nakryiko {
3357740e69c3SAndrii Nakryiko 	struct btf_type *t = btf_type_by_id(d->btf, type_id);
33582fc3fc0bSAndrii Nakryiko 	struct hashmap_entry *hash_entry;
3359d5caef5bSAndrii Nakryiko 	struct btf_type *cand;
3360d5caef5bSAndrii Nakryiko 	/* if we don't find equivalent type, then we are canonical */
3361d5caef5bSAndrii Nakryiko 	__u32 new_id = type_id;
33622fc3fc0bSAndrii Nakryiko 	__u32 cand_id;
33632fc3fc0bSAndrii Nakryiko 	long h;
3364d5caef5bSAndrii Nakryiko 
3365b03bc685SAndrii Nakryiko 	switch (btf_kind(t)) {
3366d5caef5bSAndrii Nakryiko 	case BTF_KIND_CONST:
3367d5caef5bSAndrii Nakryiko 	case BTF_KIND_VOLATILE:
3368d5caef5bSAndrii Nakryiko 	case BTF_KIND_RESTRICT:
3369d5caef5bSAndrii Nakryiko 	case BTF_KIND_PTR:
3370d5caef5bSAndrii Nakryiko 	case BTF_KIND_TYPEDEF:
3371d5caef5bSAndrii Nakryiko 	case BTF_KIND_ARRAY:
3372d5caef5bSAndrii Nakryiko 	case BTF_KIND_STRUCT:
3373d5caef5bSAndrii Nakryiko 	case BTF_KIND_UNION:
3374d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC:
3375d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC_PROTO:
3376189cf5a4SAndrii Nakryiko 	case BTF_KIND_VAR:
3377189cf5a4SAndrii Nakryiko 	case BTF_KIND_DATASEC:
3378d5caef5bSAndrii Nakryiko 		return 0;
3379d5caef5bSAndrii Nakryiko 
3380d5caef5bSAndrii Nakryiko 	case BTF_KIND_INT:
3381d5caef5bSAndrii Nakryiko 		h = btf_hash_int(t);
33822fc3fc0bSAndrii Nakryiko 		for_each_dedup_cand(d, hash_entry, h) {
33832fc3fc0bSAndrii Nakryiko 			cand_id = (__u32)(long)hash_entry->value;
3384740e69c3SAndrii Nakryiko 			cand = btf_type_by_id(d->btf, cand_id);
3385d5caef5bSAndrii Nakryiko 			if (btf_equal_int(t, cand)) {
33862fc3fc0bSAndrii Nakryiko 				new_id = cand_id;
3387d5caef5bSAndrii Nakryiko 				break;
3388d5caef5bSAndrii Nakryiko 			}
3389d5caef5bSAndrii Nakryiko 		}
3390d5caef5bSAndrii Nakryiko 		break;
3391d5caef5bSAndrii Nakryiko 
3392d5caef5bSAndrii Nakryiko 	case BTF_KIND_ENUM:
3393d5caef5bSAndrii Nakryiko 		h = btf_hash_enum(t);
33942fc3fc0bSAndrii Nakryiko 		for_each_dedup_cand(d, hash_entry, h) {
33952fc3fc0bSAndrii Nakryiko 			cand_id = (__u32)(long)hash_entry->value;
3396740e69c3SAndrii Nakryiko 			cand = btf_type_by_id(d->btf, cand_id);
3397d5caef5bSAndrii Nakryiko 			if (btf_equal_enum(t, cand)) {
33982fc3fc0bSAndrii Nakryiko 				new_id = cand_id;
3399d5caef5bSAndrii Nakryiko 				break;
3400d5caef5bSAndrii Nakryiko 			}
34019768095bSAndrii Nakryiko 			if (d->opts.dont_resolve_fwds)
34029768095bSAndrii Nakryiko 				continue;
34039768095bSAndrii Nakryiko 			if (btf_compat_enum(t, cand)) {
34049768095bSAndrii Nakryiko 				if (btf_is_enum_fwd(t)) {
34059768095bSAndrii Nakryiko 					/* resolve fwd to full enum */
34062fc3fc0bSAndrii Nakryiko 					new_id = cand_id;
34079768095bSAndrii Nakryiko 					break;
34089768095bSAndrii Nakryiko 				}
34099768095bSAndrii Nakryiko 				/* resolve canonical enum fwd to full enum */
34102fc3fc0bSAndrii Nakryiko 				d->map[cand_id] = type_id;
34119768095bSAndrii Nakryiko 			}
3412d5caef5bSAndrii Nakryiko 		}
3413d5caef5bSAndrii Nakryiko 		break;
3414d5caef5bSAndrii Nakryiko 
3415d5caef5bSAndrii Nakryiko 	case BTF_KIND_FWD:
3416d5caef5bSAndrii Nakryiko 		h = btf_hash_common(t);
34172fc3fc0bSAndrii Nakryiko 		for_each_dedup_cand(d, hash_entry, h) {
34182fc3fc0bSAndrii Nakryiko 			cand_id = (__u32)(long)hash_entry->value;
3419740e69c3SAndrii Nakryiko 			cand = btf_type_by_id(d->btf, cand_id);
3420d5caef5bSAndrii Nakryiko 			if (btf_equal_common(t, cand)) {
34212fc3fc0bSAndrii Nakryiko 				new_id = cand_id;
3422d5caef5bSAndrii Nakryiko 				break;
3423d5caef5bSAndrii Nakryiko 			}
3424d5caef5bSAndrii Nakryiko 		}
3425d5caef5bSAndrii Nakryiko 		break;
3426d5caef5bSAndrii Nakryiko 
3427d5caef5bSAndrii Nakryiko 	default:
3428d5caef5bSAndrii Nakryiko 		return -EINVAL;
3429d5caef5bSAndrii Nakryiko 	}
3430d5caef5bSAndrii Nakryiko 
3431d5caef5bSAndrii Nakryiko 	d->map[type_id] = new_id;
3432d5caef5bSAndrii Nakryiko 	if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
3433d5caef5bSAndrii Nakryiko 		return -ENOMEM;
3434d5caef5bSAndrii Nakryiko 
3435d5caef5bSAndrii Nakryiko 	return 0;
3436d5caef5bSAndrii Nakryiko }
3437d5caef5bSAndrii Nakryiko 
3438d5caef5bSAndrii Nakryiko static int btf_dedup_prim_types(struct btf_dedup *d)
3439d5caef5bSAndrii Nakryiko {
3440d5caef5bSAndrii Nakryiko 	int i, err;
3441d5caef5bSAndrii Nakryiko 
3442d5caef5bSAndrii Nakryiko 	for (i = 1; i <= d->btf->nr_types; i++) {
3443d5caef5bSAndrii Nakryiko 		err = btf_dedup_prim_type(d, i);
3444d5caef5bSAndrii Nakryiko 		if (err)
3445d5caef5bSAndrii Nakryiko 			return err;
3446d5caef5bSAndrii Nakryiko 	}
3447d5caef5bSAndrii Nakryiko 	return 0;
3448d5caef5bSAndrii Nakryiko }
3449d5caef5bSAndrii Nakryiko 
3450d5caef5bSAndrii Nakryiko /*
3451d5caef5bSAndrii Nakryiko  * Check whether type is already mapped into canonical one (could be to itself).
3452d5caef5bSAndrii Nakryiko  */
3453d5caef5bSAndrii Nakryiko static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id)
3454d5caef5bSAndrii Nakryiko {
34555aab392cSAndrii Nakryiko 	return d->map[type_id] <= BTF_MAX_NR_TYPES;
3456d5caef5bSAndrii Nakryiko }
3457d5caef5bSAndrii Nakryiko 
3458d5caef5bSAndrii Nakryiko /*
3459d5caef5bSAndrii Nakryiko  * Resolve type ID into its canonical type ID, if any; otherwise return original
3460d5caef5bSAndrii Nakryiko  * type ID. If type is FWD and is resolved into STRUCT/UNION already, follow
3461d5caef5bSAndrii Nakryiko  * STRUCT/UNION link and resolve it into canonical type ID as well.
3462d5caef5bSAndrii Nakryiko  */
3463d5caef5bSAndrii Nakryiko static inline __u32 resolve_type_id(struct btf_dedup *d, __u32 type_id)
3464d5caef5bSAndrii Nakryiko {
3465d5caef5bSAndrii Nakryiko 	while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
3466d5caef5bSAndrii Nakryiko 		type_id = d->map[type_id];
3467d5caef5bSAndrii Nakryiko 	return type_id;
3468d5caef5bSAndrii Nakryiko }
3469d5caef5bSAndrii Nakryiko 
3470d5caef5bSAndrii Nakryiko /*
3471d5caef5bSAndrii Nakryiko  * Resolve FWD to underlying STRUCT/UNION, if any; otherwise return original
3472d5caef5bSAndrii Nakryiko  * type ID.
3473d5caef5bSAndrii Nakryiko  */
3474d5caef5bSAndrii Nakryiko static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id)
3475d5caef5bSAndrii Nakryiko {
3476d5caef5bSAndrii Nakryiko 	__u32 orig_type_id = type_id;
3477d5caef5bSAndrii Nakryiko 
3478740e69c3SAndrii Nakryiko 	if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
3479d5caef5bSAndrii Nakryiko 		return type_id;
3480d5caef5bSAndrii Nakryiko 
3481d5caef5bSAndrii Nakryiko 	while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
3482d5caef5bSAndrii Nakryiko 		type_id = d->map[type_id];
3483d5caef5bSAndrii Nakryiko 
3484740e69c3SAndrii Nakryiko 	if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
3485d5caef5bSAndrii Nakryiko 		return type_id;
3486d5caef5bSAndrii Nakryiko 
3487d5caef5bSAndrii Nakryiko 	return orig_type_id;
3488d5caef5bSAndrii Nakryiko }
3489d5caef5bSAndrii Nakryiko 
3490d5caef5bSAndrii Nakryiko 
3491d5caef5bSAndrii Nakryiko static inline __u16 btf_fwd_kind(struct btf_type *t)
3492d5caef5bSAndrii Nakryiko {
3493b03bc685SAndrii Nakryiko 	return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT;
3494d5caef5bSAndrii Nakryiko }
3495d5caef5bSAndrii Nakryiko 
3496d5caef5bSAndrii Nakryiko /*
3497d5caef5bSAndrii Nakryiko  * Check equivalence of BTF type graph formed by candidate struct/union (we'll
3498d5caef5bSAndrii Nakryiko  * call it "candidate graph" in this description for brevity) to a type graph
3499d5caef5bSAndrii Nakryiko  * formed by (potential) canonical struct/union ("canonical graph" for brevity
3500d5caef5bSAndrii Nakryiko  * here, though keep in mind that not all types in canonical graph are
3501d5caef5bSAndrii Nakryiko  * necessarily canonical representatives themselves, some of them might be
3502d5caef5bSAndrii Nakryiko  * duplicates or its uniqueness might not have been established yet).
3503d5caef5bSAndrii Nakryiko  * Returns:
3504d5caef5bSAndrii Nakryiko  *  - >0, if type graphs are equivalent;
3505d5caef5bSAndrii Nakryiko  *  -  0, if not equivalent;
3506d5caef5bSAndrii Nakryiko  *  - <0, on error.
3507d5caef5bSAndrii Nakryiko  *
3508d5caef5bSAndrii Nakryiko  * Algorithm performs side-by-side DFS traversal of both type graphs and checks
3509d5caef5bSAndrii Nakryiko  * equivalence of BTF types at each step. If at any point BTF types in candidate
3510d5caef5bSAndrii Nakryiko  * and canonical graphs are not compatible structurally, whole graphs are
3511d5caef5bSAndrii Nakryiko  * incompatible. If types are structurally equivalent (i.e., all information
3512d5caef5bSAndrii Nakryiko  * except referenced type IDs is exactly the same), a mapping from `canon_id` to
3513d5caef5bSAndrii Nakryiko  * a `cand_id` is recored in hypothetical mapping (`btf_dedup->hypot_map`).
3514d5caef5bSAndrii Nakryiko  * If a type references other types, then those referenced types are checked
3515d5caef5bSAndrii Nakryiko  * for equivalence recursively.
3516d5caef5bSAndrii Nakryiko  *
3517d5caef5bSAndrii Nakryiko  * During DFS traversal, if we find that for current `canon_id` type we
3518d5caef5bSAndrii Nakryiko  * already have some mapping in hypothetical map, we check for two possible
3519d5caef5bSAndrii Nakryiko  * situations:
3520d5caef5bSAndrii Nakryiko  *   - `canon_id` is mapped to exactly the same type as `cand_id`. This will
3521d5caef5bSAndrii Nakryiko  *     happen when type graphs have cycles. In this case we assume those two
3522d5caef5bSAndrii Nakryiko  *     types are equivalent.
3523d5caef5bSAndrii Nakryiko  *   - `canon_id` is mapped to different type. This is contradiction in our
3524d5caef5bSAndrii Nakryiko  *     hypothetical mapping, because same graph in canonical graph corresponds
3525d5caef5bSAndrii Nakryiko  *     to two different types in candidate graph, which for equivalent type
3526d5caef5bSAndrii Nakryiko  *     graphs shouldn't happen. This condition terminates equivalence check
3527d5caef5bSAndrii Nakryiko  *     with negative result.
3528d5caef5bSAndrii Nakryiko  *
3529d5caef5bSAndrii Nakryiko  * If type graphs traversal exhausts types to check and find no contradiction,
3530d5caef5bSAndrii Nakryiko  * then type graphs are equivalent.
3531d5caef5bSAndrii Nakryiko  *
3532d5caef5bSAndrii Nakryiko  * When checking types for equivalence, there is one special case: FWD types.
3533d5caef5bSAndrii Nakryiko  * If FWD type resolution is allowed and one of the types (either from canonical
3534d5caef5bSAndrii Nakryiko  * or candidate graph) is FWD and other is STRUCT/UNION (depending on FWD's kind
3535d5caef5bSAndrii Nakryiko  * flag) and their names match, hypothetical mapping is updated to point from
3536d5caef5bSAndrii Nakryiko  * FWD to STRUCT/UNION. If graphs will be determined as equivalent successfully,
3537d5caef5bSAndrii Nakryiko  * this mapping will be used to record FWD -> STRUCT/UNION mapping permanently.
3538d5caef5bSAndrii Nakryiko  *
3539d5caef5bSAndrii Nakryiko  * Technically, this could lead to incorrect FWD to STRUCT/UNION resolution,
3540d5caef5bSAndrii Nakryiko  * if there are two exactly named (or anonymous) structs/unions that are
3541d5caef5bSAndrii Nakryiko  * compatible structurally, one of which has FWD field, while other is concrete
3542d5caef5bSAndrii Nakryiko  * STRUCT/UNION, but according to C sources they are different structs/unions
3543d5caef5bSAndrii Nakryiko  * that are referencing different types with the same name. This is extremely
3544d5caef5bSAndrii Nakryiko  * unlikely to happen, but btf_dedup API allows to disable FWD resolution if
3545d5caef5bSAndrii Nakryiko  * this logic is causing problems.
3546d5caef5bSAndrii Nakryiko  *
3547d5caef5bSAndrii Nakryiko  * Doing FWD resolution means that both candidate and/or canonical graphs can
3548d5caef5bSAndrii Nakryiko  * consists of portions of the graph that come from multiple compilation units.
3549d5caef5bSAndrii Nakryiko  * This is due to the fact that types within single compilation unit are always
3550d5caef5bSAndrii Nakryiko  * deduplicated and FWDs are already resolved, if referenced struct/union
3551d5caef5bSAndrii Nakryiko  * definiton is available. So, if we had unresolved FWD and found corresponding
3552d5caef5bSAndrii Nakryiko  * STRUCT/UNION, they will be from different compilation units. This
3553d5caef5bSAndrii Nakryiko  * consequently means that when we "link" FWD to corresponding STRUCT/UNION,
3554d5caef5bSAndrii Nakryiko  * type graph will likely have at least two different BTF types that describe
3555d5caef5bSAndrii Nakryiko  * same type (e.g., most probably there will be two different BTF types for the
3556d5caef5bSAndrii Nakryiko  * same 'int' primitive type) and could even have "overlapping" parts of type
3557d5caef5bSAndrii Nakryiko  * graph that describe same subset of types.
3558d5caef5bSAndrii Nakryiko  *
3559d5caef5bSAndrii Nakryiko  * This in turn means that our assumption that each type in canonical graph
3560d5caef5bSAndrii Nakryiko  * must correspond to exactly one type in candidate graph might not hold
3561d5caef5bSAndrii Nakryiko  * anymore and will make it harder to detect contradictions using hypothetical
3562d5caef5bSAndrii Nakryiko  * map. To handle this problem, we allow to follow FWD -> STRUCT/UNION
3563d5caef5bSAndrii Nakryiko  * resolution only in canonical graph. FWDs in candidate graphs are never
3564d5caef5bSAndrii Nakryiko  * resolved. To see why it's OK, let's check all possible situations w.r.t. FWDs
3565d5caef5bSAndrii Nakryiko  * that can occur:
3566d5caef5bSAndrii Nakryiko  *   - Both types in canonical and candidate graphs are FWDs. If they are
3567d5caef5bSAndrii Nakryiko  *     structurally equivalent, then they can either be both resolved to the
3568d5caef5bSAndrii Nakryiko  *     same STRUCT/UNION or not resolved at all. In both cases they are
3569d5caef5bSAndrii Nakryiko  *     equivalent and there is no need to resolve FWD on candidate side.
3570d5caef5bSAndrii Nakryiko  *   - Both types in canonical and candidate graphs are concrete STRUCT/UNION,
3571d5caef5bSAndrii Nakryiko  *     so nothing to resolve as well, algorithm will check equivalence anyway.
3572d5caef5bSAndrii Nakryiko  *   - Type in canonical graph is FWD, while type in candidate is concrete
3573d5caef5bSAndrii Nakryiko  *     STRUCT/UNION. In this case candidate graph comes from single compilation
3574d5caef5bSAndrii Nakryiko  *     unit, so there is exactly one BTF type for each unique C type. After
3575d5caef5bSAndrii Nakryiko  *     resolving FWD into STRUCT/UNION, there might be more than one BTF type
3576d5caef5bSAndrii Nakryiko  *     in canonical graph mapping to single BTF type in candidate graph, but
3577d5caef5bSAndrii Nakryiko  *     because hypothetical mapping maps from canonical to candidate types, it's
3578d5caef5bSAndrii Nakryiko  *     alright, and we still maintain the property of having single `canon_id`
3579d5caef5bSAndrii Nakryiko  *     mapping to single `cand_id` (there could be two different `canon_id`
3580d5caef5bSAndrii Nakryiko  *     mapped to the same `cand_id`, but it's not contradictory).
3581d5caef5bSAndrii Nakryiko  *   - Type in canonical graph is concrete STRUCT/UNION, while type in candidate
3582d5caef5bSAndrii Nakryiko  *     graph is FWD. In this case we are just going to check compatibility of
3583d5caef5bSAndrii Nakryiko  *     STRUCT/UNION and corresponding FWD, and if they are compatible, we'll
3584d5caef5bSAndrii Nakryiko  *     assume that whatever STRUCT/UNION FWD resolves to must be equivalent to
3585d5caef5bSAndrii Nakryiko  *     a concrete STRUCT/UNION from canonical graph. If the rest of type graphs
3586d5caef5bSAndrii Nakryiko  *     turn out equivalent, we'll re-resolve FWD to concrete STRUCT/UNION from
3587d5caef5bSAndrii Nakryiko  *     canonical graph.
3588d5caef5bSAndrii Nakryiko  */
3589d5caef5bSAndrii Nakryiko static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
3590d5caef5bSAndrii Nakryiko 			      __u32 canon_id)
3591d5caef5bSAndrii Nakryiko {
3592d5caef5bSAndrii Nakryiko 	struct btf_type *cand_type;
3593d5caef5bSAndrii Nakryiko 	struct btf_type *canon_type;
3594d5caef5bSAndrii Nakryiko 	__u32 hypot_type_id;
3595d5caef5bSAndrii Nakryiko 	__u16 cand_kind;
3596d5caef5bSAndrii Nakryiko 	__u16 canon_kind;
3597d5caef5bSAndrii Nakryiko 	int i, eq;
3598d5caef5bSAndrii Nakryiko 
3599d5caef5bSAndrii Nakryiko 	/* if both resolve to the same canonical, they must be equivalent */
3600d5caef5bSAndrii Nakryiko 	if (resolve_type_id(d, cand_id) == resolve_type_id(d, canon_id))
3601d5caef5bSAndrii Nakryiko 		return 1;
3602d5caef5bSAndrii Nakryiko 
3603d5caef5bSAndrii Nakryiko 	canon_id = resolve_fwd_id(d, canon_id);
3604d5caef5bSAndrii Nakryiko 
3605d5caef5bSAndrii Nakryiko 	hypot_type_id = d->hypot_map[canon_id];
36065aab392cSAndrii Nakryiko 	if (hypot_type_id <= BTF_MAX_NR_TYPES)
3607d5caef5bSAndrii Nakryiko 		return hypot_type_id == cand_id;
3608d5caef5bSAndrii Nakryiko 
3609d5caef5bSAndrii Nakryiko 	if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
3610d5caef5bSAndrii Nakryiko 		return -ENOMEM;
3611d5caef5bSAndrii Nakryiko 
3612740e69c3SAndrii Nakryiko 	cand_type = btf_type_by_id(d->btf, cand_id);
3613740e69c3SAndrii Nakryiko 	canon_type = btf_type_by_id(d->btf, canon_id);
3614b03bc685SAndrii Nakryiko 	cand_kind = btf_kind(cand_type);
3615b03bc685SAndrii Nakryiko 	canon_kind = btf_kind(canon_type);
3616d5caef5bSAndrii Nakryiko 
3617d5caef5bSAndrii Nakryiko 	if (cand_type->name_off != canon_type->name_off)
3618d5caef5bSAndrii Nakryiko 		return 0;
3619d5caef5bSAndrii Nakryiko 
3620d5caef5bSAndrii Nakryiko 	/* FWD <--> STRUCT/UNION equivalence check, if enabled */
3621d5caef5bSAndrii Nakryiko 	if (!d->opts.dont_resolve_fwds
3622d5caef5bSAndrii Nakryiko 	    && (cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD)
3623d5caef5bSAndrii Nakryiko 	    && cand_kind != canon_kind) {
3624d5caef5bSAndrii Nakryiko 		__u16 real_kind;
3625d5caef5bSAndrii Nakryiko 		__u16 fwd_kind;
3626d5caef5bSAndrii Nakryiko 
3627d5caef5bSAndrii Nakryiko 		if (cand_kind == BTF_KIND_FWD) {
3628d5caef5bSAndrii Nakryiko 			real_kind = canon_kind;
3629d5caef5bSAndrii Nakryiko 			fwd_kind = btf_fwd_kind(cand_type);
3630d5caef5bSAndrii Nakryiko 		} else {
3631d5caef5bSAndrii Nakryiko 			real_kind = cand_kind;
3632d5caef5bSAndrii Nakryiko 			fwd_kind = btf_fwd_kind(canon_type);
3633d5caef5bSAndrii Nakryiko 		}
3634d5caef5bSAndrii Nakryiko 		return fwd_kind == real_kind;
3635d5caef5bSAndrii Nakryiko 	}
3636d5caef5bSAndrii Nakryiko 
36379ec71c1cSAndrii Nakryiko 	if (cand_kind != canon_kind)
36389ec71c1cSAndrii Nakryiko 		return 0;
36399ec71c1cSAndrii Nakryiko 
3640d5caef5bSAndrii Nakryiko 	switch (cand_kind) {
3641d5caef5bSAndrii Nakryiko 	case BTF_KIND_INT:
3642d5caef5bSAndrii Nakryiko 		return btf_equal_int(cand_type, canon_type);
3643d5caef5bSAndrii Nakryiko 
3644d5caef5bSAndrii Nakryiko 	case BTF_KIND_ENUM:
36459768095bSAndrii Nakryiko 		if (d->opts.dont_resolve_fwds)
3646d5caef5bSAndrii Nakryiko 			return btf_equal_enum(cand_type, canon_type);
36479768095bSAndrii Nakryiko 		else
36489768095bSAndrii Nakryiko 			return btf_compat_enum(cand_type, canon_type);
3649d5caef5bSAndrii Nakryiko 
3650d5caef5bSAndrii Nakryiko 	case BTF_KIND_FWD:
3651d5caef5bSAndrii Nakryiko 		return btf_equal_common(cand_type, canon_type);
3652d5caef5bSAndrii Nakryiko 
3653d5caef5bSAndrii Nakryiko 	case BTF_KIND_CONST:
3654d5caef5bSAndrii Nakryiko 	case BTF_KIND_VOLATILE:
3655d5caef5bSAndrii Nakryiko 	case BTF_KIND_RESTRICT:
3656d5caef5bSAndrii Nakryiko 	case BTF_KIND_PTR:
3657d5caef5bSAndrii Nakryiko 	case BTF_KIND_TYPEDEF:
3658d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC:
36599768095bSAndrii Nakryiko 		if (cand_type->info != canon_type->info)
36609768095bSAndrii Nakryiko 			return 0;
3661d5caef5bSAndrii Nakryiko 		return btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
3662d5caef5bSAndrii Nakryiko 
3663d5caef5bSAndrii Nakryiko 	case BTF_KIND_ARRAY: {
3664b03bc685SAndrii Nakryiko 		const struct btf_array *cand_arr, *canon_arr;
3665d5caef5bSAndrii Nakryiko 
3666d5caef5bSAndrii Nakryiko 		if (!btf_compat_array(cand_type, canon_type))
3667d5caef5bSAndrii Nakryiko 			return 0;
3668b03bc685SAndrii Nakryiko 		cand_arr = btf_array(cand_type);
3669b03bc685SAndrii Nakryiko 		canon_arr = btf_array(canon_type);
3670d5caef5bSAndrii Nakryiko 		eq = btf_dedup_is_equiv(d,
3671d5caef5bSAndrii Nakryiko 			cand_arr->index_type, canon_arr->index_type);
3672d5caef5bSAndrii Nakryiko 		if (eq <= 0)
3673d5caef5bSAndrii Nakryiko 			return eq;
3674d5caef5bSAndrii Nakryiko 		return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type);
3675d5caef5bSAndrii Nakryiko 	}
3676d5caef5bSAndrii Nakryiko 
3677d5caef5bSAndrii Nakryiko 	case BTF_KIND_STRUCT:
3678d5caef5bSAndrii Nakryiko 	case BTF_KIND_UNION: {
3679b03bc685SAndrii Nakryiko 		const struct btf_member *cand_m, *canon_m;
3680d5caef5bSAndrii Nakryiko 		__u16 vlen;
3681d5caef5bSAndrii Nakryiko 
368291097fbeSAndrii Nakryiko 		if (!btf_shallow_equal_struct(cand_type, canon_type))
3683d5caef5bSAndrii Nakryiko 			return 0;
3684b03bc685SAndrii Nakryiko 		vlen = btf_vlen(cand_type);
3685b03bc685SAndrii Nakryiko 		cand_m = btf_members(cand_type);
3686b03bc685SAndrii Nakryiko 		canon_m = btf_members(canon_type);
3687d5caef5bSAndrii Nakryiko 		for (i = 0; i < vlen; i++) {
3688d5caef5bSAndrii Nakryiko 			eq = btf_dedup_is_equiv(d, cand_m->type, canon_m->type);
3689d5caef5bSAndrii Nakryiko 			if (eq <= 0)
3690d5caef5bSAndrii Nakryiko 				return eq;
3691d5caef5bSAndrii Nakryiko 			cand_m++;
3692d5caef5bSAndrii Nakryiko 			canon_m++;
3693d5caef5bSAndrii Nakryiko 		}
3694d5caef5bSAndrii Nakryiko 
3695d5caef5bSAndrii Nakryiko 		return 1;
3696d5caef5bSAndrii Nakryiko 	}
3697d5caef5bSAndrii Nakryiko 
3698d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC_PROTO: {
3699b03bc685SAndrii Nakryiko 		const struct btf_param *cand_p, *canon_p;
3700d5caef5bSAndrii Nakryiko 		__u16 vlen;
3701d5caef5bSAndrii Nakryiko 
3702d5caef5bSAndrii Nakryiko 		if (!btf_compat_fnproto(cand_type, canon_type))
3703d5caef5bSAndrii Nakryiko 			return 0;
3704d5caef5bSAndrii Nakryiko 		eq = btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
3705d5caef5bSAndrii Nakryiko 		if (eq <= 0)
3706d5caef5bSAndrii Nakryiko 			return eq;
3707b03bc685SAndrii Nakryiko 		vlen = btf_vlen(cand_type);
3708b03bc685SAndrii Nakryiko 		cand_p = btf_params(cand_type);
3709b03bc685SAndrii Nakryiko 		canon_p = btf_params(canon_type);
3710d5caef5bSAndrii Nakryiko 		for (i = 0; i < vlen; i++) {
3711d5caef5bSAndrii Nakryiko 			eq = btf_dedup_is_equiv(d, cand_p->type, canon_p->type);
3712d5caef5bSAndrii Nakryiko 			if (eq <= 0)
3713d5caef5bSAndrii Nakryiko 				return eq;
3714d5caef5bSAndrii Nakryiko 			cand_p++;
3715d5caef5bSAndrii Nakryiko 			canon_p++;
3716d5caef5bSAndrii Nakryiko 		}
3717d5caef5bSAndrii Nakryiko 		return 1;
3718d5caef5bSAndrii Nakryiko 	}
3719d5caef5bSAndrii Nakryiko 
3720d5caef5bSAndrii Nakryiko 	default:
3721d5caef5bSAndrii Nakryiko 		return -EINVAL;
3722d5caef5bSAndrii Nakryiko 	}
3723d5caef5bSAndrii Nakryiko 	return 0;
3724d5caef5bSAndrii Nakryiko }
3725d5caef5bSAndrii Nakryiko 
3726d5caef5bSAndrii Nakryiko /*
3727d5caef5bSAndrii Nakryiko  * Use hypothetical mapping, produced by successful type graph equivalence
3728d5caef5bSAndrii Nakryiko  * check, to augment existing struct/union canonical mapping, where possible.
3729d5caef5bSAndrii Nakryiko  *
3730d5caef5bSAndrii Nakryiko  * If BTF_KIND_FWD resolution is allowed, this mapping is also used to record
3731d5caef5bSAndrii Nakryiko  * FWD -> STRUCT/UNION correspondence as well. FWD resolution is bidirectional:
3732d5caef5bSAndrii Nakryiko  * it doesn't matter if FWD type was part of canonical graph or candidate one,
3733d5caef5bSAndrii Nakryiko  * we are recording the mapping anyway. As opposed to carefulness required
3734d5caef5bSAndrii Nakryiko  * for struct/union correspondence mapping (described below), for FWD resolution
3735d5caef5bSAndrii Nakryiko  * it's not important, as by the time that FWD type (reference type) will be
3736d5caef5bSAndrii Nakryiko  * deduplicated all structs/unions will be deduped already anyway.
3737d5caef5bSAndrii Nakryiko  *
3738d5caef5bSAndrii Nakryiko  * Recording STRUCT/UNION mapping is purely a performance optimization and is
3739d5caef5bSAndrii Nakryiko  * not required for correctness. It needs to be done carefully to ensure that
3740d5caef5bSAndrii Nakryiko  * struct/union from candidate's type graph is not mapped into corresponding
3741d5caef5bSAndrii Nakryiko  * struct/union from canonical type graph that itself hasn't been resolved into
3742d5caef5bSAndrii Nakryiko  * canonical representative. The only guarantee we have is that canonical
3743d5caef5bSAndrii Nakryiko  * struct/union was determined as canonical and that won't change. But any
3744d5caef5bSAndrii Nakryiko  * types referenced through that struct/union fields could have been not yet
3745d5caef5bSAndrii Nakryiko  * resolved, so in case like that it's too early to establish any kind of
3746d5caef5bSAndrii Nakryiko  * correspondence between structs/unions.
3747d5caef5bSAndrii Nakryiko  *
3748d5caef5bSAndrii Nakryiko  * No canonical correspondence is derived for primitive types (they are already
3749d5caef5bSAndrii Nakryiko  * deduplicated completely already anyway) or reference types (they rely on
3750d5caef5bSAndrii Nakryiko  * stability of struct/union canonical relationship for equivalence checks).
3751d5caef5bSAndrii Nakryiko  */
3752d5caef5bSAndrii Nakryiko static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
3753d5caef5bSAndrii Nakryiko {
3754d5caef5bSAndrii Nakryiko 	__u32 cand_type_id, targ_type_id;
3755d5caef5bSAndrii Nakryiko 	__u16 t_kind, c_kind;
3756d5caef5bSAndrii Nakryiko 	__u32 t_id, c_id;
3757d5caef5bSAndrii Nakryiko 	int i;
3758d5caef5bSAndrii Nakryiko 
3759d5caef5bSAndrii Nakryiko 	for (i = 0; i < d->hypot_cnt; i++) {
3760d5caef5bSAndrii Nakryiko 		cand_type_id = d->hypot_list[i];
3761d5caef5bSAndrii Nakryiko 		targ_type_id = d->hypot_map[cand_type_id];
3762d5caef5bSAndrii Nakryiko 		t_id = resolve_type_id(d, targ_type_id);
3763d5caef5bSAndrii Nakryiko 		c_id = resolve_type_id(d, cand_type_id);
3764740e69c3SAndrii Nakryiko 		t_kind = btf_kind(btf__type_by_id(d->btf, t_id));
3765740e69c3SAndrii Nakryiko 		c_kind = btf_kind(btf__type_by_id(d->btf, c_id));
3766d5caef5bSAndrii Nakryiko 		/*
3767d5caef5bSAndrii Nakryiko 		 * Resolve FWD into STRUCT/UNION.
3768d5caef5bSAndrii Nakryiko 		 * It's ok to resolve FWD into STRUCT/UNION that's not yet
3769d5caef5bSAndrii Nakryiko 		 * mapped to canonical representative (as opposed to
3770d5caef5bSAndrii Nakryiko 		 * STRUCT/UNION <--> STRUCT/UNION mapping logic below), because
3771d5caef5bSAndrii Nakryiko 		 * eventually that struct is going to be mapped and all resolved
3772d5caef5bSAndrii Nakryiko 		 * FWDs will automatically resolve to correct canonical
3773d5caef5bSAndrii Nakryiko 		 * representative. This will happen before ref type deduping,
3774d5caef5bSAndrii Nakryiko 		 * which critically depends on stability of these mapping. This
3775d5caef5bSAndrii Nakryiko 		 * stability is not a requirement for STRUCT/UNION equivalence
3776d5caef5bSAndrii Nakryiko 		 * checks, though.
3777d5caef5bSAndrii Nakryiko 		 */
3778d5caef5bSAndrii Nakryiko 		if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD)
3779d5caef5bSAndrii Nakryiko 			d->map[c_id] = t_id;
3780d5caef5bSAndrii Nakryiko 		else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
3781d5caef5bSAndrii Nakryiko 			d->map[t_id] = c_id;
3782d5caef5bSAndrii Nakryiko 
3783d5caef5bSAndrii Nakryiko 		if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) &&
3784d5caef5bSAndrii Nakryiko 		    c_kind != BTF_KIND_FWD &&
3785d5caef5bSAndrii Nakryiko 		    is_type_mapped(d, c_id) &&
3786d5caef5bSAndrii Nakryiko 		    !is_type_mapped(d, t_id)) {
3787d5caef5bSAndrii Nakryiko 			/*
3788d5caef5bSAndrii Nakryiko 			 * as a perf optimization, we can map struct/union
3789d5caef5bSAndrii Nakryiko 			 * that's part of type graph we just verified for
3790d5caef5bSAndrii Nakryiko 			 * equivalence. We can do that for struct/union that has
3791d5caef5bSAndrii Nakryiko 			 * canonical representative only, though.
3792d5caef5bSAndrii Nakryiko 			 */
3793d5caef5bSAndrii Nakryiko 			d->map[t_id] = c_id;
3794d5caef5bSAndrii Nakryiko 		}
3795d5caef5bSAndrii Nakryiko 	}
3796d5caef5bSAndrii Nakryiko }
3797d5caef5bSAndrii Nakryiko 
3798d5caef5bSAndrii Nakryiko /*
3799d5caef5bSAndrii Nakryiko  * Deduplicate struct/union types.
3800d5caef5bSAndrii Nakryiko  *
3801d5caef5bSAndrii Nakryiko  * For each struct/union type its type signature hash is calculated, taking
3802d5caef5bSAndrii Nakryiko  * into account type's name, size, number, order and names of fields, but
3803d5caef5bSAndrii Nakryiko  * ignoring type ID's referenced from fields, because they might not be deduped
3804d5caef5bSAndrii Nakryiko  * completely until after reference types deduplication phase. This type hash
3805d5caef5bSAndrii Nakryiko  * is used to iterate over all potential canonical types, sharing same hash.
3806d5caef5bSAndrii Nakryiko  * For each canonical candidate we check whether type graphs that they form
3807d5caef5bSAndrii Nakryiko  * (through referenced types in fields and so on) are equivalent using algorithm
3808d5caef5bSAndrii Nakryiko  * implemented in `btf_dedup_is_equiv`. If such equivalence is found and
3809d5caef5bSAndrii Nakryiko  * BTF_KIND_FWD resolution is allowed, then hypothetical mapping
3810d5caef5bSAndrii Nakryiko  * (btf_dedup->hypot_map) produced by aforementioned type graph equivalence
3811d5caef5bSAndrii Nakryiko  * algorithm is used to record FWD -> STRUCT/UNION mapping. It's also used to
3812d5caef5bSAndrii Nakryiko  * potentially map other structs/unions to their canonical representatives,
3813d5caef5bSAndrii Nakryiko  * if such relationship hasn't yet been established. This speeds up algorithm
3814d5caef5bSAndrii Nakryiko  * by eliminating some of the duplicate work.
3815d5caef5bSAndrii Nakryiko  *
3816d5caef5bSAndrii Nakryiko  * If no matching canonical representative was found, struct/union is marked
3817d5caef5bSAndrii Nakryiko  * as canonical for itself and is added into btf_dedup->dedup_table hash map
3818d5caef5bSAndrii Nakryiko  * for further look ups.
3819d5caef5bSAndrii Nakryiko  */
3820d5caef5bSAndrii Nakryiko static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
3821d5caef5bSAndrii Nakryiko {
382291097fbeSAndrii Nakryiko 	struct btf_type *cand_type, *t;
38232fc3fc0bSAndrii Nakryiko 	struct hashmap_entry *hash_entry;
3824d5caef5bSAndrii Nakryiko 	/* if we don't find equivalent type, then we are canonical */
3825d5caef5bSAndrii Nakryiko 	__u32 new_id = type_id;
3826d5caef5bSAndrii Nakryiko 	__u16 kind;
38272fc3fc0bSAndrii Nakryiko 	long h;
3828d5caef5bSAndrii Nakryiko 
3829d5caef5bSAndrii Nakryiko 	/* already deduped or is in process of deduping (loop detected) */
38305aab392cSAndrii Nakryiko 	if (d->map[type_id] <= BTF_MAX_NR_TYPES)
3831d5caef5bSAndrii Nakryiko 		return 0;
3832d5caef5bSAndrii Nakryiko 
3833740e69c3SAndrii Nakryiko 	t = btf_type_by_id(d->btf, type_id);
3834b03bc685SAndrii Nakryiko 	kind = btf_kind(t);
3835d5caef5bSAndrii Nakryiko 
3836d5caef5bSAndrii Nakryiko 	if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION)
3837d5caef5bSAndrii Nakryiko 		return 0;
3838d5caef5bSAndrii Nakryiko 
3839d5caef5bSAndrii Nakryiko 	h = btf_hash_struct(t);
38402fc3fc0bSAndrii Nakryiko 	for_each_dedup_cand(d, hash_entry, h) {
38412fc3fc0bSAndrii Nakryiko 		__u32 cand_id = (__u32)(long)hash_entry->value;
3842d5caef5bSAndrii Nakryiko 		int eq;
3843d5caef5bSAndrii Nakryiko 
384491097fbeSAndrii Nakryiko 		/*
384591097fbeSAndrii Nakryiko 		 * Even though btf_dedup_is_equiv() checks for
384691097fbeSAndrii Nakryiko 		 * btf_shallow_equal_struct() internally when checking two
384791097fbeSAndrii Nakryiko 		 * structs (unions) for equivalence, we need to guard here
384891097fbeSAndrii Nakryiko 		 * from picking matching FWD type as a dedup candidate.
384991097fbeSAndrii Nakryiko 		 * This can happen due to hash collision. In such case just
385091097fbeSAndrii Nakryiko 		 * relying on btf_dedup_is_equiv() would lead to potentially
385191097fbeSAndrii Nakryiko 		 * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because
385291097fbeSAndrii Nakryiko 		 * FWD and compatible STRUCT/UNION are considered equivalent.
385391097fbeSAndrii Nakryiko 		 */
3854740e69c3SAndrii Nakryiko 		cand_type = btf_type_by_id(d->btf, cand_id);
385591097fbeSAndrii Nakryiko 		if (!btf_shallow_equal_struct(t, cand_type))
385691097fbeSAndrii Nakryiko 			continue;
385791097fbeSAndrii Nakryiko 
3858d5caef5bSAndrii Nakryiko 		btf_dedup_clear_hypot_map(d);
38592fc3fc0bSAndrii Nakryiko 		eq = btf_dedup_is_equiv(d, type_id, cand_id);
3860d5caef5bSAndrii Nakryiko 		if (eq < 0)
3861d5caef5bSAndrii Nakryiko 			return eq;
3862d5caef5bSAndrii Nakryiko 		if (!eq)
3863d5caef5bSAndrii Nakryiko 			continue;
38642fc3fc0bSAndrii Nakryiko 		new_id = cand_id;
3865d5caef5bSAndrii Nakryiko 		btf_dedup_merge_hypot_map(d);
3866d5caef5bSAndrii Nakryiko 		break;
3867d5caef5bSAndrii Nakryiko 	}
3868d5caef5bSAndrii Nakryiko 
3869d5caef5bSAndrii Nakryiko 	d->map[type_id] = new_id;
3870d5caef5bSAndrii Nakryiko 	if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
3871d5caef5bSAndrii Nakryiko 		return -ENOMEM;
3872d5caef5bSAndrii Nakryiko 
3873d5caef5bSAndrii Nakryiko 	return 0;
3874d5caef5bSAndrii Nakryiko }
3875d5caef5bSAndrii Nakryiko 
3876d5caef5bSAndrii Nakryiko static int btf_dedup_struct_types(struct btf_dedup *d)
3877d5caef5bSAndrii Nakryiko {
3878d5caef5bSAndrii Nakryiko 	int i, err;
3879d5caef5bSAndrii Nakryiko 
3880d5caef5bSAndrii Nakryiko 	for (i = 1; i <= d->btf->nr_types; i++) {
3881d5caef5bSAndrii Nakryiko 		err = btf_dedup_struct_type(d, i);
3882d5caef5bSAndrii Nakryiko 		if (err)
3883d5caef5bSAndrii Nakryiko 			return err;
3884d5caef5bSAndrii Nakryiko 	}
3885d5caef5bSAndrii Nakryiko 	return 0;
3886d5caef5bSAndrii Nakryiko }
3887d5caef5bSAndrii Nakryiko 
3888d5caef5bSAndrii Nakryiko /*
3889d5caef5bSAndrii Nakryiko  * Deduplicate reference type.
3890d5caef5bSAndrii Nakryiko  *
3891d5caef5bSAndrii Nakryiko  * Once all primitive and struct/union types got deduplicated, we can easily
3892d5caef5bSAndrii Nakryiko  * deduplicate all other (reference) BTF types. This is done in two steps:
3893d5caef5bSAndrii Nakryiko  *
3894d5caef5bSAndrii Nakryiko  * 1. Resolve all referenced type IDs into their canonical type IDs. This
3895d5caef5bSAndrii Nakryiko  * resolution can be done either immediately for primitive or struct/union types
3896d5caef5bSAndrii Nakryiko  * (because they were deduped in previous two phases) or recursively for
3897d5caef5bSAndrii Nakryiko  * reference types. Recursion will always terminate at either primitive or
3898d5caef5bSAndrii Nakryiko  * struct/union type, at which point we can "unwind" chain of reference types
3899d5caef5bSAndrii Nakryiko  * one by one. There is no danger of encountering cycles because in C type
3900d5caef5bSAndrii Nakryiko  * system the only way to form type cycle is through struct/union, so any chain
3901d5caef5bSAndrii Nakryiko  * of reference types, even those taking part in a type cycle, will inevitably
3902d5caef5bSAndrii Nakryiko  * reach struct/union at some point.
3903d5caef5bSAndrii Nakryiko  *
3904d5caef5bSAndrii Nakryiko  * 2. Once all referenced type IDs are resolved into canonical ones, BTF type
3905d5caef5bSAndrii Nakryiko  * becomes "stable", in the sense that no further deduplication will cause
3906d5caef5bSAndrii Nakryiko  * any changes to it. With that, it's now possible to calculate type's signature
3907d5caef5bSAndrii Nakryiko  * hash (this time taking into account referenced type IDs) and loop over all
3908d5caef5bSAndrii Nakryiko  * potential canonical representatives. If no match was found, current type
3909d5caef5bSAndrii Nakryiko  * will become canonical representative of itself and will be added into
3910d5caef5bSAndrii Nakryiko  * btf_dedup->dedup_table as another possible canonical representative.
3911d5caef5bSAndrii Nakryiko  */
3912d5caef5bSAndrii Nakryiko static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
3913d5caef5bSAndrii Nakryiko {
39142fc3fc0bSAndrii Nakryiko 	struct hashmap_entry *hash_entry;
39152fc3fc0bSAndrii Nakryiko 	__u32 new_id = type_id, cand_id;
3916d5caef5bSAndrii Nakryiko 	struct btf_type *t, *cand;
3917d5caef5bSAndrii Nakryiko 	/* if we don't find equivalent type, then we are representative type */
39183d8669e6SDan Carpenter 	int ref_type_id;
39192fc3fc0bSAndrii Nakryiko 	long h;
3920d5caef5bSAndrii Nakryiko 
3921d5caef5bSAndrii Nakryiko 	if (d->map[type_id] == BTF_IN_PROGRESS_ID)
3922d5caef5bSAndrii Nakryiko 		return -ELOOP;
39235aab392cSAndrii Nakryiko 	if (d->map[type_id] <= BTF_MAX_NR_TYPES)
3924d5caef5bSAndrii Nakryiko 		return resolve_type_id(d, type_id);
3925d5caef5bSAndrii Nakryiko 
3926740e69c3SAndrii Nakryiko 	t = btf_type_by_id(d->btf, type_id);
3927d5caef5bSAndrii Nakryiko 	d->map[type_id] = BTF_IN_PROGRESS_ID;
3928d5caef5bSAndrii Nakryiko 
3929b03bc685SAndrii Nakryiko 	switch (btf_kind(t)) {
3930d5caef5bSAndrii Nakryiko 	case BTF_KIND_CONST:
3931d5caef5bSAndrii Nakryiko 	case BTF_KIND_VOLATILE:
3932d5caef5bSAndrii Nakryiko 	case BTF_KIND_RESTRICT:
3933d5caef5bSAndrii Nakryiko 	case BTF_KIND_PTR:
3934d5caef5bSAndrii Nakryiko 	case BTF_KIND_TYPEDEF:
3935d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC:
3936d5caef5bSAndrii Nakryiko 		ref_type_id = btf_dedup_ref_type(d, t->type);
3937d5caef5bSAndrii Nakryiko 		if (ref_type_id < 0)
3938d5caef5bSAndrii Nakryiko 			return ref_type_id;
3939d5caef5bSAndrii Nakryiko 		t->type = ref_type_id;
3940d5caef5bSAndrii Nakryiko 
3941d5caef5bSAndrii Nakryiko 		h = btf_hash_common(t);
39422fc3fc0bSAndrii Nakryiko 		for_each_dedup_cand(d, hash_entry, h) {
39432fc3fc0bSAndrii Nakryiko 			cand_id = (__u32)(long)hash_entry->value;
3944740e69c3SAndrii Nakryiko 			cand = btf_type_by_id(d->btf, cand_id);
3945d5caef5bSAndrii Nakryiko 			if (btf_equal_common(t, cand)) {
39462fc3fc0bSAndrii Nakryiko 				new_id = cand_id;
3947d5caef5bSAndrii Nakryiko 				break;
3948d5caef5bSAndrii Nakryiko 			}
3949d5caef5bSAndrii Nakryiko 		}
3950d5caef5bSAndrii Nakryiko 		break;
3951d5caef5bSAndrii Nakryiko 
3952d5caef5bSAndrii Nakryiko 	case BTF_KIND_ARRAY: {
3953b03bc685SAndrii Nakryiko 		struct btf_array *info = btf_array(t);
3954d5caef5bSAndrii Nakryiko 
3955d5caef5bSAndrii Nakryiko 		ref_type_id = btf_dedup_ref_type(d, info->type);
3956d5caef5bSAndrii Nakryiko 		if (ref_type_id < 0)
3957d5caef5bSAndrii Nakryiko 			return ref_type_id;
3958d5caef5bSAndrii Nakryiko 		info->type = ref_type_id;
3959d5caef5bSAndrii Nakryiko 
3960d5caef5bSAndrii Nakryiko 		ref_type_id = btf_dedup_ref_type(d, info->index_type);
3961d5caef5bSAndrii Nakryiko 		if (ref_type_id < 0)
3962d5caef5bSAndrii Nakryiko 			return ref_type_id;
3963d5caef5bSAndrii Nakryiko 		info->index_type = ref_type_id;
3964d5caef5bSAndrii Nakryiko 
3965d5caef5bSAndrii Nakryiko 		h = btf_hash_array(t);
39662fc3fc0bSAndrii Nakryiko 		for_each_dedup_cand(d, hash_entry, h) {
39672fc3fc0bSAndrii Nakryiko 			cand_id = (__u32)(long)hash_entry->value;
3968740e69c3SAndrii Nakryiko 			cand = btf_type_by_id(d->btf, cand_id);
3969d5caef5bSAndrii Nakryiko 			if (btf_equal_array(t, cand)) {
39702fc3fc0bSAndrii Nakryiko 				new_id = cand_id;
3971d5caef5bSAndrii Nakryiko 				break;
3972d5caef5bSAndrii Nakryiko 			}
3973d5caef5bSAndrii Nakryiko 		}
3974d5caef5bSAndrii Nakryiko 		break;
3975d5caef5bSAndrii Nakryiko 	}
3976d5caef5bSAndrii Nakryiko 
3977d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC_PROTO: {
3978d5caef5bSAndrii Nakryiko 		struct btf_param *param;
3979d5caef5bSAndrii Nakryiko 		__u16 vlen;
3980d5caef5bSAndrii Nakryiko 		int i;
3981d5caef5bSAndrii Nakryiko 
3982d5caef5bSAndrii Nakryiko 		ref_type_id = btf_dedup_ref_type(d, t->type);
3983d5caef5bSAndrii Nakryiko 		if (ref_type_id < 0)
3984d5caef5bSAndrii Nakryiko 			return ref_type_id;
3985d5caef5bSAndrii Nakryiko 		t->type = ref_type_id;
3986d5caef5bSAndrii Nakryiko 
3987b03bc685SAndrii Nakryiko 		vlen = btf_vlen(t);
3988b03bc685SAndrii Nakryiko 		param = btf_params(t);
3989d5caef5bSAndrii Nakryiko 		for (i = 0; i < vlen; i++) {
3990d5caef5bSAndrii Nakryiko 			ref_type_id = btf_dedup_ref_type(d, param->type);
3991d5caef5bSAndrii Nakryiko 			if (ref_type_id < 0)
3992d5caef5bSAndrii Nakryiko 				return ref_type_id;
3993d5caef5bSAndrii Nakryiko 			param->type = ref_type_id;
3994d5caef5bSAndrii Nakryiko 			param++;
3995d5caef5bSAndrii Nakryiko 		}
3996d5caef5bSAndrii Nakryiko 
3997d5caef5bSAndrii Nakryiko 		h = btf_hash_fnproto(t);
39982fc3fc0bSAndrii Nakryiko 		for_each_dedup_cand(d, hash_entry, h) {
39992fc3fc0bSAndrii Nakryiko 			cand_id = (__u32)(long)hash_entry->value;
4000740e69c3SAndrii Nakryiko 			cand = btf_type_by_id(d->btf, cand_id);
4001d5caef5bSAndrii Nakryiko 			if (btf_equal_fnproto(t, cand)) {
40022fc3fc0bSAndrii Nakryiko 				new_id = cand_id;
4003d5caef5bSAndrii Nakryiko 				break;
4004d5caef5bSAndrii Nakryiko 			}
4005d5caef5bSAndrii Nakryiko 		}
4006d5caef5bSAndrii Nakryiko 		break;
4007d5caef5bSAndrii Nakryiko 	}
4008d5caef5bSAndrii Nakryiko 
4009d5caef5bSAndrii Nakryiko 	default:
4010d5caef5bSAndrii Nakryiko 		return -EINVAL;
4011d5caef5bSAndrii Nakryiko 	}
4012d5caef5bSAndrii Nakryiko 
4013d5caef5bSAndrii Nakryiko 	d->map[type_id] = new_id;
4014d5caef5bSAndrii Nakryiko 	if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
4015d5caef5bSAndrii Nakryiko 		return -ENOMEM;
4016d5caef5bSAndrii Nakryiko 
4017d5caef5bSAndrii Nakryiko 	return new_id;
4018d5caef5bSAndrii Nakryiko }
4019d5caef5bSAndrii Nakryiko 
4020d5caef5bSAndrii Nakryiko static int btf_dedup_ref_types(struct btf_dedup *d)
4021d5caef5bSAndrii Nakryiko {
4022d5caef5bSAndrii Nakryiko 	int i, err;
4023d5caef5bSAndrii Nakryiko 
4024d5caef5bSAndrii Nakryiko 	for (i = 1; i <= d->btf->nr_types; i++) {
4025d5caef5bSAndrii Nakryiko 		err = btf_dedup_ref_type(d, i);
4026d5caef5bSAndrii Nakryiko 		if (err < 0)
4027d5caef5bSAndrii Nakryiko 			return err;
4028d5caef5bSAndrii Nakryiko 	}
40292fc3fc0bSAndrii Nakryiko 	/* we won't need d->dedup_table anymore */
40302fc3fc0bSAndrii Nakryiko 	hashmap__free(d->dedup_table);
40312fc3fc0bSAndrii Nakryiko 	d->dedup_table = NULL;
4032d5caef5bSAndrii Nakryiko 	return 0;
4033d5caef5bSAndrii Nakryiko }
4034d5caef5bSAndrii Nakryiko 
4035d5caef5bSAndrii Nakryiko /*
4036d5caef5bSAndrii Nakryiko  * Compact types.
4037d5caef5bSAndrii Nakryiko  *
4038d5caef5bSAndrii Nakryiko  * After we established for each type its corresponding canonical representative
4039d5caef5bSAndrii Nakryiko  * type, we now can eliminate types that are not canonical and leave only
4040d5caef5bSAndrii Nakryiko  * canonical ones layed out sequentially in memory by copying them over
4041d5caef5bSAndrii Nakryiko  * duplicates. During compaction btf_dedup->hypot_map array is reused to store
4042d5caef5bSAndrii Nakryiko  * a map from original type ID to a new compacted type ID, which will be used
4043d5caef5bSAndrii Nakryiko  * during next phase to "fix up" type IDs, referenced from struct/union and
4044d5caef5bSAndrii Nakryiko  * reference types.
4045d5caef5bSAndrii Nakryiko  */
4046d5caef5bSAndrii Nakryiko static int btf_dedup_compact_types(struct btf_dedup *d)
4047d5caef5bSAndrii Nakryiko {
4048740e69c3SAndrii Nakryiko 	__u32 *new_offs;
4049d5caef5bSAndrii Nakryiko 	__u32 next_type_id = 1;
4050740e69c3SAndrii Nakryiko 	void *p;
4051d5caef5bSAndrii Nakryiko 	int i, len;
4052d5caef5bSAndrii Nakryiko 
4053d5caef5bSAndrii Nakryiko 	/* we are going to reuse hypot_map to store compaction remapping */
4054d5caef5bSAndrii Nakryiko 	d->hypot_map[0] = 0;
4055d5caef5bSAndrii Nakryiko 	for (i = 1; i <= d->btf->nr_types; i++)
4056d5caef5bSAndrii Nakryiko 		d->hypot_map[i] = BTF_UNPROCESSED_ID;
4057d5caef5bSAndrii Nakryiko 
4058740e69c3SAndrii Nakryiko 	p = d->btf->types_data;
4059d5caef5bSAndrii Nakryiko 
4060d5caef5bSAndrii Nakryiko 	for (i = 1; i <= d->btf->nr_types; i++) {
4061d5caef5bSAndrii Nakryiko 		if (d->map[i] != i)
4062d5caef5bSAndrii Nakryiko 			continue;
4063d5caef5bSAndrii Nakryiko 
4064740e69c3SAndrii Nakryiko 		len = btf_type_size(btf__type_by_id(d->btf, i));
4065d5caef5bSAndrii Nakryiko 		if (len < 0)
4066d5caef5bSAndrii Nakryiko 			return len;
4067d5caef5bSAndrii Nakryiko 
4068740e69c3SAndrii Nakryiko 		memmove(p, btf__type_by_id(d->btf, i), len);
4069d5caef5bSAndrii Nakryiko 		d->hypot_map[i] = next_type_id;
4070740e69c3SAndrii Nakryiko 		d->btf->type_offs[next_type_id] = p - d->btf->types_data;
4071d5caef5bSAndrii Nakryiko 		p += len;
4072d5caef5bSAndrii Nakryiko 		next_type_id++;
4073d5caef5bSAndrii Nakryiko 	}
4074d5caef5bSAndrii Nakryiko 
4075d5caef5bSAndrii Nakryiko 	/* shrink struct btf's internal types index and update btf_header */
4076d5caef5bSAndrii Nakryiko 	d->btf->nr_types = next_type_id - 1;
4077740e69c3SAndrii Nakryiko 	d->btf->type_offs_cap = d->btf->nr_types + 1;
4078740e69c3SAndrii Nakryiko 	d->btf->hdr->type_len = p - d->btf->types_data;
4079740e69c3SAndrii Nakryiko 	new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap,
4080740e69c3SAndrii Nakryiko 				       sizeof(*new_offs));
4081740e69c3SAndrii Nakryiko 	if (!new_offs)
4082d5caef5bSAndrii Nakryiko 		return -ENOMEM;
4083740e69c3SAndrii Nakryiko 	d->btf->type_offs = new_offs;
4084919d2b1dSAndrii Nakryiko 	d->btf->hdr->str_off = d->btf->hdr->type_len;
4085b8604247SAndrii Nakryiko 	d->btf->raw_size = d->btf->hdr->hdr_len + d->btf->hdr->type_len + d->btf->hdr->str_len;
4086d5caef5bSAndrii Nakryiko 	return 0;
4087d5caef5bSAndrii Nakryiko }
4088d5caef5bSAndrii Nakryiko 
4089d5caef5bSAndrii Nakryiko /*
4090d5caef5bSAndrii Nakryiko  * Figure out final (deduplicated and compacted) type ID for provided original
4091d5caef5bSAndrii Nakryiko  * `type_id` by first resolving it into corresponding canonical type ID and
4092d5caef5bSAndrii Nakryiko  * then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map,
4093d5caef5bSAndrii Nakryiko  * which is populated during compaction phase.
4094d5caef5bSAndrii Nakryiko  */
4095d5caef5bSAndrii Nakryiko static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id)
4096d5caef5bSAndrii Nakryiko {
4097d5caef5bSAndrii Nakryiko 	__u32 resolved_type_id, new_type_id;
4098d5caef5bSAndrii Nakryiko 
4099d5caef5bSAndrii Nakryiko 	resolved_type_id = resolve_type_id(d, type_id);
4100d5caef5bSAndrii Nakryiko 	new_type_id = d->hypot_map[resolved_type_id];
41015aab392cSAndrii Nakryiko 	if (new_type_id > BTF_MAX_NR_TYPES)
4102d5caef5bSAndrii Nakryiko 		return -EINVAL;
4103d5caef5bSAndrii Nakryiko 	return new_type_id;
4104d5caef5bSAndrii Nakryiko }
4105d5caef5bSAndrii Nakryiko 
4106d5caef5bSAndrii Nakryiko /*
4107d5caef5bSAndrii Nakryiko  * Remap referenced type IDs into deduped type IDs.
4108d5caef5bSAndrii Nakryiko  *
4109d5caef5bSAndrii Nakryiko  * After BTF types are deduplicated and compacted, their final type IDs may
4110d5caef5bSAndrii Nakryiko  * differ from original ones. The map from original to a corresponding
4111d5caef5bSAndrii Nakryiko  * deduped type ID is stored in btf_dedup->hypot_map and is populated during
4112d5caef5bSAndrii Nakryiko  * compaction phase. During remapping phase we are rewriting all type IDs
4113d5caef5bSAndrii Nakryiko  * referenced from any BTF type (e.g., struct fields, func proto args, etc) to
4114d5caef5bSAndrii Nakryiko  * their final deduped type IDs.
4115d5caef5bSAndrii Nakryiko  */
4116d5caef5bSAndrii Nakryiko static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id)
4117d5caef5bSAndrii Nakryiko {
4118740e69c3SAndrii Nakryiko 	struct btf_type *t = btf_type_by_id(d->btf, type_id);
4119d5caef5bSAndrii Nakryiko 	int i, r;
4120d5caef5bSAndrii Nakryiko 
4121b03bc685SAndrii Nakryiko 	switch (btf_kind(t)) {
4122d5caef5bSAndrii Nakryiko 	case BTF_KIND_INT:
4123d5caef5bSAndrii Nakryiko 	case BTF_KIND_ENUM:
4124d5caef5bSAndrii Nakryiko 		break;
4125d5caef5bSAndrii Nakryiko 
4126d5caef5bSAndrii Nakryiko 	case BTF_KIND_FWD:
4127d5caef5bSAndrii Nakryiko 	case BTF_KIND_CONST:
4128d5caef5bSAndrii Nakryiko 	case BTF_KIND_VOLATILE:
4129d5caef5bSAndrii Nakryiko 	case BTF_KIND_RESTRICT:
4130d5caef5bSAndrii Nakryiko 	case BTF_KIND_PTR:
4131d5caef5bSAndrii Nakryiko 	case BTF_KIND_TYPEDEF:
4132d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC:
4133189cf5a4SAndrii Nakryiko 	case BTF_KIND_VAR:
4134d5caef5bSAndrii Nakryiko 		r = btf_dedup_remap_type_id(d, t->type);
4135d5caef5bSAndrii Nakryiko 		if (r < 0)
4136d5caef5bSAndrii Nakryiko 			return r;
4137d5caef5bSAndrii Nakryiko 		t->type = r;
4138d5caef5bSAndrii Nakryiko 		break;
4139d5caef5bSAndrii Nakryiko 
4140d5caef5bSAndrii Nakryiko 	case BTF_KIND_ARRAY: {
4141b03bc685SAndrii Nakryiko 		struct btf_array *arr_info = btf_array(t);
4142d5caef5bSAndrii Nakryiko 
4143d5caef5bSAndrii Nakryiko 		r = btf_dedup_remap_type_id(d, arr_info->type);
4144d5caef5bSAndrii Nakryiko 		if (r < 0)
4145d5caef5bSAndrii Nakryiko 			return r;
4146d5caef5bSAndrii Nakryiko 		arr_info->type = r;
4147d5caef5bSAndrii Nakryiko 		r = btf_dedup_remap_type_id(d, arr_info->index_type);
4148d5caef5bSAndrii Nakryiko 		if (r < 0)
4149d5caef5bSAndrii Nakryiko 			return r;
4150d5caef5bSAndrii Nakryiko 		arr_info->index_type = r;
4151d5caef5bSAndrii Nakryiko 		break;
4152d5caef5bSAndrii Nakryiko 	}
4153d5caef5bSAndrii Nakryiko 
4154d5caef5bSAndrii Nakryiko 	case BTF_KIND_STRUCT:
4155d5caef5bSAndrii Nakryiko 	case BTF_KIND_UNION: {
4156b03bc685SAndrii Nakryiko 		struct btf_member *member = btf_members(t);
4157b03bc685SAndrii Nakryiko 		__u16 vlen = btf_vlen(t);
4158d5caef5bSAndrii Nakryiko 
4159d5caef5bSAndrii Nakryiko 		for (i = 0; i < vlen; i++) {
4160d5caef5bSAndrii Nakryiko 			r = btf_dedup_remap_type_id(d, member->type);
4161d5caef5bSAndrii Nakryiko 			if (r < 0)
4162d5caef5bSAndrii Nakryiko 				return r;
4163d5caef5bSAndrii Nakryiko 			member->type = r;
4164d5caef5bSAndrii Nakryiko 			member++;
4165d5caef5bSAndrii Nakryiko 		}
4166d5caef5bSAndrii Nakryiko 		break;
4167d5caef5bSAndrii Nakryiko 	}
4168d5caef5bSAndrii Nakryiko 
4169d5caef5bSAndrii Nakryiko 	case BTF_KIND_FUNC_PROTO: {
4170b03bc685SAndrii Nakryiko 		struct btf_param *param = btf_params(t);
4171b03bc685SAndrii Nakryiko 		__u16 vlen = btf_vlen(t);
4172d5caef5bSAndrii Nakryiko 
4173d5caef5bSAndrii Nakryiko 		r = btf_dedup_remap_type_id(d, t->type);
4174d5caef5bSAndrii Nakryiko 		if (r < 0)
4175d5caef5bSAndrii Nakryiko 			return r;
4176d5caef5bSAndrii Nakryiko 		t->type = r;
4177d5caef5bSAndrii Nakryiko 
4178d5caef5bSAndrii Nakryiko 		for (i = 0; i < vlen; i++) {
4179d5caef5bSAndrii Nakryiko 			r = btf_dedup_remap_type_id(d, param->type);
4180d5caef5bSAndrii Nakryiko 			if (r < 0)
4181d5caef5bSAndrii Nakryiko 				return r;
4182d5caef5bSAndrii Nakryiko 			param->type = r;
4183d5caef5bSAndrii Nakryiko 			param++;
4184d5caef5bSAndrii Nakryiko 		}
4185d5caef5bSAndrii Nakryiko 		break;
4186d5caef5bSAndrii Nakryiko 	}
4187d5caef5bSAndrii Nakryiko 
4188189cf5a4SAndrii Nakryiko 	case BTF_KIND_DATASEC: {
4189b03bc685SAndrii Nakryiko 		struct btf_var_secinfo *var = btf_var_secinfos(t);
4190b03bc685SAndrii Nakryiko 		__u16 vlen = btf_vlen(t);
4191189cf5a4SAndrii Nakryiko 
4192189cf5a4SAndrii Nakryiko 		for (i = 0; i < vlen; i++) {
4193189cf5a4SAndrii Nakryiko 			r = btf_dedup_remap_type_id(d, var->type);
4194189cf5a4SAndrii Nakryiko 			if (r < 0)
4195189cf5a4SAndrii Nakryiko 				return r;
4196189cf5a4SAndrii Nakryiko 			var->type = r;
4197189cf5a4SAndrii Nakryiko 			var++;
4198189cf5a4SAndrii Nakryiko 		}
4199189cf5a4SAndrii Nakryiko 		break;
4200189cf5a4SAndrii Nakryiko 	}
4201189cf5a4SAndrii Nakryiko 
4202d5caef5bSAndrii Nakryiko 	default:
4203d5caef5bSAndrii Nakryiko 		return -EINVAL;
4204d5caef5bSAndrii Nakryiko 	}
4205d5caef5bSAndrii Nakryiko 
4206d5caef5bSAndrii Nakryiko 	return 0;
4207d5caef5bSAndrii Nakryiko }
4208d5caef5bSAndrii Nakryiko 
4209d5caef5bSAndrii Nakryiko static int btf_dedup_remap_types(struct btf_dedup *d)
4210d5caef5bSAndrii Nakryiko {
4211d5caef5bSAndrii Nakryiko 	int i, r;
4212d5caef5bSAndrii Nakryiko 
4213d5caef5bSAndrii Nakryiko 	for (i = 1; i <= d->btf->nr_types; i++) {
4214d5caef5bSAndrii Nakryiko 		r = btf_dedup_remap_type(d, i);
4215d5caef5bSAndrii Nakryiko 		if (r < 0)
4216d5caef5bSAndrii Nakryiko 			return r;
4217d5caef5bSAndrii Nakryiko 	}
4218d5caef5bSAndrii Nakryiko 	return 0;
4219d5caef5bSAndrii Nakryiko }
4220fb2426adSMartin KaFai Lau 
4221fb2426adSMartin KaFai Lau /*
4222fb2426adSMartin KaFai Lau  * Probe few well-known locations for vmlinux kernel image and try to load BTF
4223fb2426adSMartin KaFai Lau  * data out of it to use for target BTF.
4224fb2426adSMartin KaFai Lau  */
4225fb2426adSMartin KaFai Lau struct btf *libbpf_find_kernel_btf(void)
4226fb2426adSMartin KaFai Lau {
4227fb2426adSMartin KaFai Lau 	struct {
4228fb2426adSMartin KaFai Lau 		const char *path_fmt;
4229fb2426adSMartin KaFai Lau 		bool raw_btf;
4230fb2426adSMartin KaFai Lau 	} locations[] = {
4231fb2426adSMartin KaFai Lau 		/* try canonical vmlinux BTF through sysfs first */
4232fb2426adSMartin KaFai Lau 		{ "/sys/kernel/btf/vmlinux", true /* raw BTF */ },
4233fb2426adSMartin KaFai Lau 		/* fall back to trying to find vmlinux ELF on disk otherwise */
4234fb2426adSMartin KaFai Lau 		{ "/boot/vmlinux-%1$s" },
4235fb2426adSMartin KaFai Lau 		{ "/lib/modules/%1$s/vmlinux-%1$s" },
4236fb2426adSMartin KaFai Lau 		{ "/lib/modules/%1$s/build/vmlinux" },
4237fb2426adSMartin KaFai Lau 		{ "/usr/lib/modules/%1$s/kernel/vmlinux" },
4238fb2426adSMartin KaFai Lau 		{ "/usr/lib/debug/boot/vmlinux-%1$s" },
4239fb2426adSMartin KaFai Lau 		{ "/usr/lib/debug/boot/vmlinux-%1$s.debug" },
4240fb2426adSMartin KaFai Lau 		{ "/usr/lib/debug/lib/modules/%1$s/vmlinux" },
4241fb2426adSMartin KaFai Lau 	};
4242fb2426adSMartin KaFai Lau 	char path[PATH_MAX + 1];
4243fb2426adSMartin KaFai Lau 	struct utsname buf;
4244fb2426adSMartin KaFai Lau 	struct btf *btf;
4245fb2426adSMartin KaFai Lau 	int i;
4246fb2426adSMartin KaFai Lau 
4247fb2426adSMartin KaFai Lau 	uname(&buf);
4248fb2426adSMartin KaFai Lau 
4249fb2426adSMartin KaFai Lau 	for (i = 0; i < ARRAY_SIZE(locations); i++) {
4250fb2426adSMartin KaFai Lau 		snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release);
4251fb2426adSMartin KaFai Lau 
4252fb2426adSMartin KaFai Lau 		if (access(path, R_OK))
4253fb2426adSMartin KaFai Lau 			continue;
4254fb2426adSMartin KaFai Lau 
4255fb2426adSMartin KaFai Lau 		if (locations[i].raw_btf)
425694a1feddSAndrii Nakryiko 			btf = btf__parse_raw(path);
4257fb2426adSMartin KaFai Lau 		else
4258fb2426adSMartin KaFai Lau 			btf = btf__parse_elf(path, NULL);
4259fb2426adSMartin KaFai Lau 
4260fb2426adSMartin KaFai Lau 		pr_debug("loading kernel BTF '%s': %ld\n",
4261fb2426adSMartin KaFai Lau 			 path, IS_ERR(btf) ? PTR_ERR(btf) : 0);
4262fb2426adSMartin KaFai Lau 		if (IS_ERR(btf))
4263fb2426adSMartin KaFai Lau 			continue;
4264fb2426adSMartin KaFai Lau 
4265fb2426adSMartin KaFai Lau 		return btf;
4266fb2426adSMartin KaFai Lau 	}
4267fb2426adSMartin KaFai Lau 
4268fb2426adSMartin KaFai Lau 	pr_warn("failed to find valid kernel BTF\n");
4269fb2426adSMartin KaFai Lau 	return ERR_PTR(-ESRCH);
4270fb2426adSMartin KaFai Lau }
4271