xref: /openbmc/linux/arch/powerpc/kernel/module.c (revision 3a2699cf)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*  Kernel module help for powerpc.
3     Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
4     Copyright (C) 2008 Freescale Semiconductor, Inc.
5 
6 */
7 #include <linux/elf.h>
8 #include <linux/moduleloader.h>
9 #include <linux/err.h>
10 #include <linux/vmalloc.h>
11 #include <linux/mm.h>
12 #include <linux/bug.h>
13 #include <asm/module.h>
14 #include <linux/uaccess.h>
15 #include <asm/firmware.h>
16 #include <linux/sort.h>
17 #include <asm/setup.h>
18 #include <asm/sections.h>
19 
20 static LIST_HEAD(module_bug_list);
21 
22 static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
23 				    const Elf_Shdr *sechdrs,
24 				    const char *name)
25 {
26 	char *secstrings;
27 	unsigned int i;
28 
29 	secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
30 	for (i = 1; i < hdr->e_shnum; i++)
31 		if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
32 			return &sechdrs[i];
33 	return NULL;
34 }
35 
36 int module_finalize(const Elf_Ehdr *hdr,
37 		const Elf_Shdr *sechdrs, struct module *me)
38 {
39 	const Elf_Shdr *sect;
40 	int rc;
41 
42 	rc = module_finalize_ftrace(me, sechdrs);
43 	if (rc)
44 		return rc;
45 
46 	/* Apply feature fixups */
47 	sect = find_section(hdr, sechdrs, "__ftr_fixup");
48 	if (sect != NULL)
49 		do_feature_fixups(cur_cpu_spec->cpu_features,
50 				  (void *)sect->sh_addr,
51 				  (void *)sect->sh_addr + sect->sh_size);
52 
53 	sect = find_section(hdr, sechdrs, "__mmu_ftr_fixup");
54 	if (sect != NULL)
55 		do_feature_fixups(cur_cpu_spec->mmu_features,
56 				  (void *)sect->sh_addr,
57 				  (void *)sect->sh_addr + sect->sh_size);
58 
59 #ifdef CONFIG_PPC64
60 	sect = find_section(hdr, sechdrs, "__fw_ftr_fixup");
61 	if (sect != NULL)
62 		do_feature_fixups(powerpc_firmware_features,
63 				  (void *)sect->sh_addr,
64 				  (void *)sect->sh_addr + sect->sh_size);
65 #endif /* CONFIG_PPC64 */
66 
67 #ifdef PPC64_ELF_ABI_v1
68 	sect = find_section(hdr, sechdrs, ".opd");
69 	if (sect != NULL) {
70 		me->arch.start_opd = sect->sh_addr;
71 		me->arch.end_opd = sect->sh_addr + sect->sh_size;
72 	}
73 #endif /* PPC64_ELF_ABI_v1 */
74 
75 #ifdef CONFIG_PPC_BARRIER_NOSPEC
76 	sect = find_section(hdr, sechdrs, "__spec_barrier_fixup");
77 	if (sect != NULL)
78 		do_barrier_nospec_fixups_range(barrier_nospec_enabled,
79 				  (void *)sect->sh_addr,
80 				  (void *)sect->sh_addr + sect->sh_size);
81 #endif /* CONFIG_PPC_BARRIER_NOSPEC */
82 
83 	sect = find_section(hdr, sechdrs, "__lwsync_fixup");
84 	if (sect != NULL)
85 		do_lwsync_fixups(cur_cpu_spec->cpu_features,
86 				 (void *)sect->sh_addr,
87 				 (void *)sect->sh_addr + sect->sh_size);
88 
89 	return 0;
90 }
91 
92 static __always_inline void *
93 __module_alloc(unsigned long size, unsigned long start, unsigned long end, bool nowarn)
94 {
95 	pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL : PAGE_KERNEL_EXEC;
96 	gfp_t gfp = GFP_KERNEL | (nowarn ? __GFP_NOWARN : 0);
97 
98 	/*
99 	 * Don't do huge page allocations for modules yet until more testing
100 	 * is done. STRICT_MODULE_RWX may require extra work to support this
101 	 * too.
102 	 */
103 	return __vmalloc_node_range(size, 1, start, end, gfp, prot,
104 				    VM_FLUSH_RESET_PERMS,
105 				    NUMA_NO_NODE, __builtin_return_address(0));
106 }
107 
108 void *module_alloc(unsigned long size)
109 {
110 #ifdef MODULES_VADDR
111 	unsigned long limit = (unsigned long)_etext - SZ_32M;
112 	void *ptr = NULL;
113 
114 	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
115 
116 	/* First try within 32M limit from _etext to avoid branch trampolines */
117 	if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit)
118 		ptr = __module_alloc(size, limit, MODULES_END, true);
119 
120 	if (!ptr)
121 		ptr = __module_alloc(size, MODULES_VADDR, MODULES_END, false);
122 
123 	return ptr;
124 #else
125 	return __module_alloc(size, VMALLOC_START, VMALLOC_END, false);
126 #endif
127 }
128