1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Copyright (C) 2015 Imagination Technologies
4 * Author: Alex Smith <alex.smith@imgtec.com>
5 */
6
7 static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
8 {
9 const ELF(Ehdr) *ehdr = vdso;
10 void *shdrs;
11 ELF(Shdr) *shdr;
12 char *shstrtab, *name;
13 uint16_t sh_count, sh_entsize, i;
14
15 shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
16 sh_count = swap_uint16(ehdr->e_shnum);
17 sh_entsize = swap_uint16(ehdr->e_shentsize);
18
19 shdr = shdrs + (sh_entsize * swap_uint16(ehdr->e_shstrndx));
20 shstrtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
21
22 for (i = 0; i < sh_count; i++) {
23 shdr = shdrs + (i * sh_entsize);
24 name = shstrtab + swap_uint32(shdr->sh_name);
25
26 /*
27 * Ensure there are no relocation sections - ld.so does not
28 * relocate the VDSO so if there are relocations things will
29 * break.
30 */
31 switch (swap_uint32(shdr->sh_type)) {
32 case SHT_REL:
33 case SHT_RELA:
34 fprintf(stderr,
35 "%s: '%s' contains relocation sections\n",
36 program_name, path);
37 return false;
38 }
39
40 /* Check for existing sections. */
41 if (strcmp(name, ".MIPS.abiflags") == 0) {
42 fprintf(stderr,
43 "%s: '%s' already contains a '.MIPS.abiflags' section\n",
44 program_name, path);
45 return false;
46 }
47
48 if (strcmp(name, ".mips_abiflags") == 0) {
49 strcpy(name, ".MIPS.abiflags");
50 shdr->sh_type = swap_uint32(SHT_MIPS_ABIFLAGS);
51 shdr->sh_entsize = shdr->sh_size;
52 }
53 }
54
55 return true;
56 }
57
58 static inline bool FUNC(get_symbols)(const char *path, void *vdso)
59 {
60 const ELF(Ehdr) *ehdr = vdso;
61 void *shdrs, *symtab;
62 ELF(Shdr) *shdr;
63 const ELF(Sym) *sym;
64 char *strtab, *name;
65 uint16_t sh_count, sh_entsize, st_count, st_entsize, i, j;
66 uint64_t offset;
67 uint32_t flags;
68
69 shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
70 sh_count = swap_uint16(ehdr->e_shnum);
71 sh_entsize = swap_uint16(ehdr->e_shentsize);
72
73 for (i = 0; i < sh_count; i++) {
74 shdr = shdrs + (i * sh_entsize);
75
76 if (swap_uint32(shdr->sh_type) == SHT_SYMTAB)
77 break;
78 }
79
80 if (i == sh_count) {
81 fprintf(stderr, "%s: '%s' has no symbol table\n", program_name,
82 path);
83 return false;
84 }
85
86 /* Get flags */
87 flags = swap_uint32(ehdr->e_flags);
88 if (elf_class == ELFCLASS64)
89 elf_abi = ABI_N64;
90 else if (flags & EF_MIPS_ABI2)
91 elf_abi = ABI_N32;
92 else
93 elf_abi = ABI_O32;
94
95 /* Get symbol table. */
96 symtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
97 st_entsize = FUNC(swap_uint)(shdr->sh_entsize);
98 st_count = FUNC(swap_uint)(shdr->sh_size) / st_entsize;
99
100 /* Get string table. */
101 shdr = shdrs + (swap_uint32(shdr->sh_link) * sh_entsize);
102 strtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
103
104 /* Write offsets for symbols needed by the kernel. */
105 for (i = 0; vdso_symbols[i].name; i++) {
106 if (!(vdso_symbols[i].abis & elf_abi))
107 continue;
108
109 for (j = 0; j < st_count; j++) {
110 sym = symtab + (j * st_entsize);
111 name = strtab + swap_uint32(sym->st_name);
112
113 if (!strcmp(name, vdso_symbols[i].name)) {
114 offset = FUNC(swap_uint)(sym->st_value);
115
116 fprintf(out_file,
117 "\t.%s = 0x%" PRIx64 ",\n",
118 vdso_symbols[i].offset_name, offset);
119 break;
120 }
121 }
122
123 if (j == st_count) {
124 fprintf(stderr,
125 "%s: '%s' is missing required symbol '%s'\n",
126 program_name, path, vdso_symbols[i].name);
127 return false;
128 }
129 }
130
131 return true;
132 }
133
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