1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2 /* Copyright (c) 2019 Facebook */ 3 4 #ifndef __RELO_CORE_H 5 #define __RELO_CORE_H 6 7 #include <linux/bpf.h> 8 9 struct bpf_core_cand { 10 const struct btf *btf; 11 __u32 id; 12 }; 13 14 /* dynamically sized list of type IDs and its associated struct btf */ 15 struct bpf_core_cand_list { 16 struct bpf_core_cand *cands; 17 int len; 18 }; 19 20 #define BPF_CORE_SPEC_MAX_LEN 64 21 22 /* represents BPF CO-RE field or array element accessor */ 23 struct bpf_core_accessor { 24 __u32 type_id; /* struct/union type or array element type */ 25 __u32 idx; /* field index or array index */ 26 const char *name; /* field name or NULL for array accessor */ 27 }; 28 29 struct bpf_core_spec { 30 const struct btf *btf; 31 /* high-level spec: named fields and array indices only */ 32 struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN]; 33 /* original unresolved (no skip_mods_or_typedefs) root type ID */ 34 __u32 root_type_id; 35 /* CO-RE relocation kind */ 36 enum bpf_core_relo_kind relo_kind; 37 /* high-level spec length */ 38 int len; 39 /* raw, low-level spec: 1-to-1 with accessor spec string */ 40 int raw_spec[BPF_CORE_SPEC_MAX_LEN]; 41 /* raw spec length */ 42 int raw_len; 43 /* field bit offset represented by spec */ 44 __u32 bit_offset; 45 }; 46 47 struct bpf_core_relo_res { 48 /* expected value in the instruction, unless validate == false */ 49 __u32 orig_val; 50 /* new value that needs to be patched up to */ 51 __u32 new_val; 52 /* relocation unsuccessful, poison instruction, but don't fail load */ 53 bool poison; 54 /* some relocations can't be validated against orig_val */ 55 bool validate; 56 /* for field byte offset relocations or the forms: 57 * *(T *)(rX + <off>) = rY 58 * rX = *(T *)(rY + <off>), 59 * we remember original and resolved field size to adjust direct 60 * memory loads of pointers and integers; this is necessary for 32-bit 61 * host kernel architectures, but also allows to automatically 62 * relocate fields that were resized from, e.g., u32 to u64, etc. 63 */ 64 bool fail_memsz_adjust; 65 __u32 orig_sz; 66 __u32 orig_type_id; 67 __u32 new_sz; 68 __u32 new_type_id; 69 }; 70 71 int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, 72 const struct btf *targ_btf, __u32 targ_id); 73 74 size_t bpf_core_essential_name_len(const char *name); 75 76 int bpf_core_calc_relo_insn(const char *prog_name, 77 const struct bpf_core_relo *relo, int relo_idx, 78 const struct btf *local_btf, 79 struct bpf_core_cand_list *cands, 80 struct bpf_core_spec *specs_scratch, 81 struct bpf_core_relo_res *targ_res); 82 83 int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn, 84 int insn_idx, const struct bpf_core_relo *relo, 85 int relo_idx, const struct bpf_core_relo_res *res); 86 87 #endif 88