1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * sortextable.h
4 *
5 * Copyright 2011 - 2012 Cavium, Inc.
6 *
7 * Some of this code was taken out of recordmcount.h written by:
8 *
9 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
10 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
11 */
12
13 #undef extable_ent_size
14 #undef compare_extable
15 #undef do_func
16 #undef Elf_Addr
17 #undef Elf_Ehdr
18 #undef Elf_Shdr
19 #undef Elf_Rel
20 #undef Elf_Rela
21 #undef Elf_Sym
22 #undef ELF_R_SYM
23 #undef Elf_r_sym
24 #undef ELF_R_INFO
25 #undef Elf_r_info
26 #undef ELF_ST_BIND
27 #undef ELF_ST_TYPE
28 #undef fn_ELF_R_SYM
29 #undef fn_ELF_R_INFO
30 #undef uint_t
31 #undef _r
32 #undef _w
33
34 #ifdef SORTEXTABLE_64
35 # define extable_ent_size 16
36 # define compare_extable compare_extable_64
37 # define do_func do64
38 # define Elf_Addr Elf64_Addr
39 # define Elf_Ehdr Elf64_Ehdr
40 # define Elf_Shdr Elf64_Shdr
41 # define Elf_Rel Elf64_Rel
42 # define Elf_Rela Elf64_Rela
43 # define Elf_Sym Elf64_Sym
44 # define ELF_R_SYM ELF64_R_SYM
45 # define Elf_r_sym Elf64_r_sym
46 # define ELF_R_INFO ELF64_R_INFO
47 # define Elf_r_info Elf64_r_info
48 # define ELF_ST_BIND ELF64_ST_BIND
49 # define ELF_ST_TYPE ELF64_ST_TYPE
50 # define fn_ELF_R_SYM fn_ELF64_R_SYM
51 # define fn_ELF_R_INFO fn_ELF64_R_INFO
52 # define uint_t uint64_t
53 # define _r r8
54 # define _w w8
55 #else
56 # define extable_ent_size 8
57 # define compare_extable compare_extable_32
58 # define do_func do32
59 # define Elf_Addr Elf32_Addr
60 # define Elf_Ehdr Elf32_Ehdr
61 # define Elf_Shdr Elf32_Shdr
62 # define Elf_Rel Elf32_Rel
63 # define Elf_Rela Elf32_Rela
64 # define Elf_Sym Elf32_Sym
65 # define ELF_R_SYM ELF32_R_SYM
66 # define Elf_r_sym Elf32_r_sym
67 # define ELF_R_INFO ELF32_R_INFO
68 # define Elf_r_info Elf32_r_info
69 # define ELF_ST_BIND ELF32_ST_BIND
70 # define ELF_ST_TYPE ELF32_ST_TYPE
71 # define fn_ELF_R_SYM fn_ELF32_R_SYM
72 # define fn_ELF_R_INFO fn_ELF32_R_INFO
73 # define uint_t uint32_t
74 # define _r r
75 # define _w w
76 #endif
77
compare_extable(const void * a,const void * b)78 static int compare_extable(const void *a, const void *b)
79 {
80 Elf_Addr av = _r(a);
81 Elf_Addr bv = _r(b);
82
83 if (av < bv)
84 return -1;
85 if (av > bv)
86 return 1;
87 return 0;
88 }
89
90 static void
do_func(Elf_Ehdr * ehdr,char const * const fname,table_sort_t custom_sort)91 do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
92 {
93 Elf_Shdr *shdr;
94 Elf_Shdr *shstrtab_sec;
95 Elf_Shdr *strtab_sec = NULL;
96 Elf_Shdr *symtab_sec = NULL;
97 Elf_Shdr *extab_sec = NULL;
98 Elf_Sym *sym;
99 const Elf_Sym *symtab;
100 Elf32_Word *symtab_shndx_start = NULL;
101 Elf_Sym *sort_needed_sym;
102 Elf_Shdr *sort_needed_sec;
103 Elf_Rel *relocs = NULL;
104 int relocs_size = 0;
105 uint32_t *sort_done_location;
106 const char *secstrtab;
107 const char *strtab;
108 char *extab_image;
109 int extab_index = 0;
110 int i;
111 int idx;
112 unsigned int num_sections;
113 unsigned int secindex_strings;
114
115 shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
116
117 num_sections = r2(&ehdr->e_shnum);
118 if (num_sections == SHN_UNDEF)
119 num_sections = _r(&shdr[0].sh_size);
120
121 secindex_strings = r2(&ehdr->e_shstrndx);
122 if (secindex_strings == SHN_XINDEX)
123 secindex_strings = r(&shdr[0].sh_link);
124
125 shstrtab_sec = shdr + secindex_strings;
126 secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
127 for (i = 0; i < num_sections; i++) {
128 idx = r(&shdr[i].sh_name);
129 if (strcmp(secstrtab + idx, "__ex_table") == 0) {
130 extab_sec = shdr + i;
131 extab_index = i;
132 }
133 if ((r(&shdr[i].sh_type) == SHT_REL ||
134 r(&shdr[i].sh_type) == SHT_RELA) &&
135 r(&shdr[i].sh_info) == extab_index) {
136 relocs = (void *)ehdr + _r(&shdr[i].sh_offset);
137 relocs_size = _r(&shdr[i].sh_size);
138 }
139 if (strcmp(secstrtab + idx, ".symtab") == 0)
140 symtab_sec = shdr + i;
141 if (strcmp(secstrtab + idx, ".strtab") == 0)
142 strtab_sec = shdr + i;
143 if (r(&shdr[i].sh_type) == SHT_SYMTAB_SHNDX)
144 symtab_shndx_start = (Elf32_Word *)(
145 (const char *)ehdr + _r(&shdr[i].sh_offset));
146 }
147 if (strtab_sec == NULL) {
148 fprintf(stderr, "no .strtab in file: %s\n", fname);
149 fail_file();
150 }
151 if (symtab_sec == NULL) {
152 fprintf(stderr, "no .symtab in file: %s\n", fname);
153 fail_file();
154 }
155 symtab = (const Elf_Sym *)((const char *)ehdr +
156 _r(&symtab_sec->sh_offset));
157 if (extab_sec == NULL) {
158 fprintf(stderr, "no __ex_table in file: %s\n", fname);
159 fail_file();
160 }
161 strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
162
163 extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
164
165 if (custom_sort) {
166 custom_sort(extab_image, _r(&extab_sec->sh_size));
167 } else {
168 int num_entries = _r(&extab_sec->sh_size) / extable_ent_size;
169 qsort(extab_image, num_entries,
170 extable_ent_size, compare_extable);
171 }
172 /* If there were relocations, we no longer need them. */
173 if (relocs)
174 memset(relocs, 0, relocs_size);
175
176 /* find main_extable_sort_needed */
177 sort_needed_sym = NULL;
178 for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
179 sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
180 sym += i;
181 if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
182 continue;
183 idx = r(&sym->st_name);
184 if (strcmp(strtab + idx, "main_extable_sort_needed") == 0) {
185 sort_needed_sym = sym;
186 break;
187 }
188 }
189 if (sort_needed_sym == NULL) {
190 fprintf(stderr,
191 "no main_extable_sort_needed symbol in file: %s\n",
192 fname);
193 fail_file();
194 }
195 sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
196 sort_needed_sym - symtab,
197 symtab_shndx_start)];
198 sort_done_location = (void *)ehdr +
199 _r(&sort_needed_sec->sh_offset) +
200 _r(&sort_needed_sym->st_value) -
201 _r(&sort_needed_sec->sh_addr);
202
203 #if 0
204 printf("sort done marker at %lx\n",
205 (unsigned long)((char *)sort_done_location - (char *)ehdr));
206 #endif
207 /* We sorted it, clear the flag. */
208 w(0, sort_done_location);
209 }
210
