1 /*
2 * sortextable.h
3 *
4 * Copyright 2011 - 2012 Cavium, Inc.
5 *
6 * Some of this code was taken out of recordmcount.h written by:
7 *
8 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
9 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
10 *
11 *
12 * Licensed under the GNU General Public License, version 2 (GPLv2).
13 */
14
15 #undef extable_ent_size
16 #undef compare_extable
17 #undef do_func
18 #undef Elf_Addr
19 #undef Elf_Ehdr
20 #undef Elf_Shdr
21 #undef Elf_Rel
22 #undef Elf_Rela
23 #undef Elf_Sym
24 #undef ELF_R_SYM
25 #undef Elf_r_sym
26 #undef ELF_R_INFO
27 #undef Elf_r_info
28 #undef ELF_ST_BIND
29 #undef ELF_ST_TYPE
30 #undef fn_ELF_R_SYM
31 #undef fn_ELF_R_INFO
32 #undef uint_t
33 #undef _r
34 #undef _w
35
36 #ifdef SORTEXTABLE_64
37 # define extable_ent_size 16
38 # define compare_extable compare_extable_64
39 # define do_func do64
40 # define Elf_Addr Elf64_Addr
41 # define Elf_Ehdr Elf64_Ehdr
42 # define Elf_Shdr Elf64_Shdr
43 # define Elf_Rel Elf64_Rel
44 # define Elf_Rela Elf64_Rela
45 # define Elf_Sym Elf64_Sym
46 # define ELF_R_SYM ELF64_R_SYM
47 # define Elf_r_sym Elf64_r_sym
48 # define ELF_R_INFO ELF64_R_INFO
49 # define Elf_r_info Elf64_r_info
50 # define ELF_ST_BIND ELF64_ST_BIND
51 # define ELF_ST_TYPE ELF64_ST_TYPE
52 # define fn_ELF_R_SYM fn_ELF64_R_SYM
53 # define fn_ELF_R_INFO fn_ELF64_R_INFO
54 # define uint_t uint64_t
55 # define _r r8
56 # define _w w8
57 #else
58 # define extable_ent_size 8
59 # define compare_extable compare_extable_32
60 # define do_func do32
61 # define Elf_Addr Elf32_Addr
62 # define Elf_Ehdr Elf32_Ehdr
63 # define Elf_Shdr Elf32_Shdr
64 # define Elf_Rel Elf32_Rel
65 # define Elf_Rela Elf32_Rela
66 # define Elf_Sym Elf32_Sym
67 # define ELF_R_SYM ELF32_R_SYM
68 # define Elf_r_sym Elf32_r_sym
69 # define ELF_R_INFO ELF32_R_INFO
70 # define Elf_r_info Elf32_r_info
71 # define ELF_ST_BIND ELF32_ST_BIND
72 # define ELF_ST_TYPE ELF32_ST_TYPE
73 # define fn_ELF_R_SYM fn_ELF32_R_SYM
74 # define fn_ELF_R_INFO fn_ELF32_R_INFO
75 # define uint_t uint32_t
76 # define _r r
77 # define _w w
78 #endif
79
compare_extable(const void * a,const void * b)80 static int compare_extable(const void *a, const void *b)
81 {
82 Elf_Addr av = _r(a);
83 Elf_Addr bv = _r(b);
84
85 if (av < bv)
86 return -1;
87 if (av > bv)
88 return 1;
89 return 0;
90 }
91
92 static void
do_func(Elf_Ehdr * ehdr,char const * const fname,table_sort_t custom_sort)93 do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
94 {
95 Elf_Shdr *shdr;
96 Elf_Shdr *shstrtab_sec;
97 Elf_Shdr *strtab_sec = NULL;
98 Elf_Shdr *symtab_sec = NULL;
99 Elf_Shdr *extab_sec = NULL;
100 Elf_Sym *sym;
101 const Elf_Sym *symtab;
102 Elf32_Word *symtab_shndx_start = NULL;
103 Elf_Sym *sort_needed_sym;
104 Elf_Shdr *sort_needed_sec;
105 Elf_Rel *relocs = NULL;
106 int relocs_size = 0;
107 uint32_t *sort_done_location;
108 const char *secstrtab;
109 const char *strtab;
110 char *extab_image;
111 int extab_index = 0;
112 int i;
113 int idx;
114 unsigned int num_sections;
115 unsigned int secindex_strings;
116
117 shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
118
119 num_sections = r2(&ehdr->e_shnum);
120 if (num_sections == SHN_UNDEF)
121 num_sections = _r(&shdr[0].sh_size);
122
123 secindex_strings = r2(&ehdr->e_shstrndx);
124 if (secindex_strings == SHN_XINDEX)
125 secindex_strings = r(&shdr[0].sh_link);
126
127 shstrtab_sec = shdr + secindex_strings;
128 secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
129 for (i = 0; i < num_sections; i++) {
130 idx = r(&shdr[i].sh_name);
131 if (strcmp(secstrtab + idx, "__ex_table") == 0) {
132 extab_sec = shdr + i;
133 extab_index = i;
134 }
135 if ((r(&shdr[i].sh_type) == SHT_REL ||
136 r(&shdr[i].sh_type) == SHT_RELA) &&
137 r(&shdr[i].sh_info) == extab_index) {
138 relocs = (void *)ehdr + _r(&shdr[i].sh_offset);
139 relocs_size = _r(&shdr[i].sh_size);
140 }
141 if (strcmp(secstrtab + idx, ".symtab") == 0)
142 symtab_sec = shdr + i;
143 if (strcmp(secstrtab + idx, ".strtab") == 0)
144 strtab_sec = shdr + i;
145 if (r(&shdr[i].sh_type) == SHT_SYMTAB_SHNDX)
146 symtab_shndx_start = (Elf32_Word *)(
147 (const char *)ehdr + _r(&shdr[i].sh_offset));
148 }
149 if (strtab_sec == NULL) {
150 fprintf(stderr, "no .strtab in file: %s\n", fname);
151 fail_file();
152 }
153 if (symtab_sec == NULL) {
154 fprintf(stderr, "no .symtab in file: %s\n", fname);
155 fail_file();
156 }
157 symtab = (const Elf_Sym *)((const char *)ehdr +
158 _r(&symtab_sec->sh_offset));
159 if (extab_sec == NULL) {
160 fprintf(stderr, "no __ex_table in file: %s\n", fname);
161 fail_file();
162 }
163 strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
164
165 extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
166
167 if (custom_sort) {
168 custom_sort(extab_image, _r(&extab_sec->sh_size));
169 } else {
170 int num_entries = _r(&extab_sec->sh_size) / extable_ent_size;
171 qsort(extab_image, num_entries,
172 extable_ent_size, compare_extable);
173 }
174 /* If there were relocations, we no longer need them. */
175 if (relocs)
176 memset(relocs, 0, relocs_size);
177
178 /* find main_extable_sort_needed */
179 sort_needed_sym = NULL;
180 for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
181 sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
182 sym += i;
183 if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
184 continue;
185 idx = r(&sym->st_name);
186 if (strcmp(strtab + idx, "main_extable_sort_needed") == 0) {
187 sort_needed_sym = sym;
188 break;
189 }
190 }
191 if (sort_needed_sym == NULL) {
192 fprintf(stderr,
193 "no main_extable_sort_needed symbol in file: %s\n",
194 fname);
195 fail_file();
196 }
197 sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
198 sort_needed_sym - symtab,
199 symtab_shndx_start)];
200 sort_done_location = (void *)ehdr +
201 _r(&sort_needed_sec->sh_offset) +
202 _r(&sort_needed_sym->st_value) -
203 _r(&sort_needed_sec->sh_addr);
204
205 #if 0
206 printf("sort done marker at %lx\n",
207 (unsigned long)((char *)sort_done_location - (char *)ehdr));
208 #endif
209 /* We sorted it, clear the flag. */
210 w(0, sort_done_location);
211 }
212
