8fac3fd697a6ec34c4908ca60386f2dee3c29bb0
[sfrench/cifs-2.6.git] / scripts / sortextable.h
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
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
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;
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 }