diff options
author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
---|---|---|
committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /arch/x86/boot | |
parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) |
Diffstat (limited to 'arch/x86/boot')
-rw-r--r-- | arch/x86/boot/compressed/relocs.c | 682 |
1 files changed, 682 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c new file mode 100644 index 00000000000..89bbf4e4d05 --- /dev/null +++ b/arch/x86/boot/compressed/relocs.c | |||
@@ -0,0 +1,682 @@ | |||
1 | #include <stdio.h> | ||
2 | #include <stdarg.h> | ||
3 | #include <stdlib.h> | ||
4 | #include <stdint.h> | ||
5 | #include <string.h> | ||
6 | #include <errno.h> | ||
7 | #include <unistd.h> | ||
8 | #include <elf.h> | ||
9 | #include <byteswap.h> | ||
10 | #define USE_BSD | ||
11 | #include <endian.h> | ||
12 | #include <regex.h> | ||
13 | |||
14 | static void die(char *fmt, ...); | ||
15 | |||
16 | #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) | ||
17 | static Elf32_Ehdr ehdr; | ||
18 | static unsigned long reloc_count, reloc_idx; | ||
19 | static unsigned long *relocs; | ||
20 | |||
21 | struct section { | ||
22 | Elf32_Shdr shdr; | ||
23 | struct section *link; | ||
24 | Elf32_Sym *symtab; | ||
25 | Elf32_Rel *reltab; | ||
26 | char *strtab; | ||
27 | }; | ||
28 | static struct section *secs; | ||
29 | |||
30 | /* | ||
31 | * Following symbols have been audited. There values are constant and do | ||
32 | * not change if bzImage is loaded at a different physical address than | ||
33 | * the address for which it has been compiled. Don't warn user about | ||
34 | * absolute relocations present w.r.t these symbols. | ||
35 | */ | ||
36 | static const char abs_sym_regex[] = | ||
37 | "^(xen_irq_disable_direct_reloc$|" | ||
38 | "xen_save_fl_direct_reloc$|" | ||
39 | "VDSO|" | ||
40 | "__crc_)"; | ||
41 | static regex_t abs_sym_regex_c; | ||
42 | static int is_abs_reloc(const char *sym_name) | ||
43 | { | ||
44 | return !regexec(&abs_sym_regex_c, sym_name, 0, NULL, 0); | ||
45 | } | ||
46 | |||
47 | /* | ||
48 | * These symbols are known to be relative, even if the linker marks them | ||
49 | * as absolute (typically defined outside any section in the linker script.) | ||
50 | */ | ||
51 | static const char rel_sym_regex[] = | ||
52 | "^_end$"; | ||
53 | static regex_t rel_sym_regex_c; | ||
54 | static int is_rel_reloc(const char *sym_name) | ||
55 | { | ||
56 | return !regexec(&rel_sym_regex_c, sym_name, 0, NULL, 0); | ||
57 | } | ||
58 | |||
59 | static void regex_init(void) | ||
60 | { | ||
61 | char errbuf[128]; | ||
62 | int err; | ||
63 | |||
64 | err = regcomp(&abs_sym_regex_c, abs_sym_regex, | ||
65 | REG_EXTENDED|REG_NOSUB); | ||
66 | if (err) { | ||
67 | regerror(err, &abs_sym_regex_c, errbuf, sizeof errbuf); | ||
68 | die("%s", errbuf); | ||
69 | } | ||
70 | |||
71 | err = regcomp(&rel_sym_regex_c, rel_sym_regex, | ||
72 | REG_EXTENDED|REG_NOSUB); | ||
73 | if (err) { | ||
74 | regerror(err, &rel_sym_regex_c, errbuf, sizeof errbuf); | ||
75 | die("%s", errbuf); | ||
76 | } | ||
77 | } | ||
78 | |||
79 | static void die(char *fmt, ...) | ||
80 | { | ||
81 | va_list ap; | ||
82 | va_start(ap, fmt); | ||
83 | vfprintf(stderr, fmt, ap); | ||
84 | va_end(ap); | ||
85 | exit(1); | ||
86 | } | ||
87 | |||
88 | static const char *sym_type(unsigned type) | ||
89 | { | ||
90 | static const char *type_name[] = { | ||
91 | #define SYM_TYPE(X) [X] = #X | ||
92 | SYM_TYPE(STT_NOTYPE), | ||
93 | SYM_TYPE(STT_OBJECT), | ||
94 | SYM_TYPE(STT_FUNC), | ||
95 | SYM_TYPE(STT_SECTION), | ||
96 | SYM_TYPE(STT_FILE), | ||
97 | SYM_TYPE(STT_COMMON), | ||
98 | SYM_TYPE(STT_TLS), | ||
99 | #undef SYM_TYPE | ||
100 | }; | ||
101 | const char *name = "unknown sym type name"; | ||
102 | if (type < ARRAY_SIZE(type_name)) { | ||
103 | name = type_name[type]; | ||
104 | } | ||
105 | return name; | ||
106 | } | ||
107 | |||
108 | static const char *sym_bind(unsigned bind) | ||
109 | { | ||
110 | static const char *bind_name[] = { | ||
111 | #define SYM_BIND(X) [X] = #X | ||
112 | SYM_BIND(STB_LOCAL), | ||
113 | SYM_BIND(STB_GLOBAL), | ||
114 | SYM_BIND(STB_WEAK), | ||
115 | #undef SYM_BIND | ||
116 | }; | ||
117 | const char *name = "unknown sym bind name"; | ||
118 | if (bind < ARRAY_SIZE(bind_name)) { | ||
119 | name = bind_name[bind]; | ||
120 | } | ||
121 | return name; | ||
122 | } | ||
123 | |||
124 | static const char *sym_visibility(unsigned visibility) | ||
125 | { | ||
126 | static const char *visibility_name[] = { | ||
127 | #define SYM_VISIBILITY(X) [X] = #X | ||
128 | SYM_VISIBILITY(STV_DEFAULT), | ||
129 | SYM_VISIBILITY(STV_INTERNAL), | ||
130 | SYM_VISIBILITY(STV_HIDDEN), | ||
131 | SYM_VISIBILITY(STV_PROTECTED), | ||
132 | #undef SYM_VISIBILITY | ||
133 | }; | ||
134 | const char *name = "unknown sym visibility name"; | ||
135 | if (visibility < ARRAY_SIZE(visibility_name)) { | ||
136 | name = visibility_name[visibility]; | ||
137 | } | ||
138 | return name; | ||
139 | } | ||
140 | |||
141 | static const char *rel_type(unsigned type) | ||
142 | { | ||
143 | static const char *type_name[] = { | ||
144 | #define REL_TYPE(X) [X] = #X | ||
145 | REL_TYPE(R_386_NONE), | ||
146 | REL_TYPE(R_386_32), | ||
147 | REL_TYPE(R_386_PC32), | ||
148 | REL_TYPE(R_386_GOT32), | ||
149 | REL_TYPE(R_386_PLT32), | ||
150 | REL_TYPE(R_386_COPY), | ||
151 | REL_TYPE(R_386_GLOB_DAT), | ||
152 | REL_TYPE(R_386_JMP_SLOT), | ||
153 | REL_TYPE(R_386_RELATIVE), | ||
154 | REL_TYPE(R_386_GOTOFF), | ||
155 | REL_TYPE(R_386_GOTPC), | ||
156 | #undef REL_TYPE | ||
157 | }; | ||
158 | const char *name = "unknown type rel type name"; | ||
159 | if (type < ARRAY_SIZE(type_name) && type_name[type]) { | ||
160 | name = type_name[type]; | ||
161 | } | ||
162 | return name; | ||
163 | } | ||
164 | |||
165 | static const char *sec_name(unsigned shndx) | ||
166 | { | ||
167 | const char *sec_strtab; | ||
168 | const char *name; | ||
169 | sec_strtab = secs[ehdr.e_shstrndx].strtab; | ||
170 | name = "<noname>"; | ||
171 | if (shndx < ehdr.e_shnum) { | ||
172 | name = sec_strtab + secs[shndx].shdr.sh_name; | ||
173 | } | ||
174 | else if (shndx == SHN_ABS) { | ||
175 | name = "ABSOLUTE"; | ||
176 | } | ||
177 | else if (shndx == SHN_COMMON) { | ||
178 | name = "COMMON"; | ||
179 | } | ||
180 | return name; | ||
181 | } | ||
182 | |||
183 | static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym) | ||
184 | { | ||
185 | const char *name; | ||
186 | name = "<noname>"; | ||
187 | if (sym->st_name) { | ||
188 | name = sym_strtab + sym->st_name; | ||
189 | } | ||
190 | else { | ||
191 | name = sec_name(secs[sym->st_shndx].shdr.sh_name); | ||
192 | } | ||
193 | return name; | ||
194 | } | ||
195 | |||
196 | |||
197 | |||
198 | #if BYTE_ORDER == LITTLE_ENDIAN | ||
199 | #define le16_to_cpu(val) (val) | ||
200 | #define le32_to_cpu(val) (val) | ||
201 | #endif | ||
202 | #if BYTE_ORDER == BIG_ENDIAN | ||
203 | #define le16_to_cpu(val) bswap_16(val) | ||
204 | #define le32_to_cpu(val) bswap_32(val) | ||
205 | #endif | ||
206 | |||
207 | static uint16_t elf16_to_cpu(uint16_t val) | ||
208 | { | ||
209 | return le16_to_cpu(val); | ||
210 | } | ||
211 | |||
212 | static uint32_t elf32_to_cpu(uint32_t val) | ||
213 | { | ||
214 | return le32_to_cpu(val); | ||
215 | } | ||
216 | |||
217 | static void read_ehdr(FILE *fp) | ||
218 | { | ||
219 | if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) { | ||
220 | die("Cannot read ELF header: %s\n", | ||
221 | strerror(errno)); | ||
222 | } | ||
223 | if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) { | ||
224 | die("No ELF magic\n"); | ||
225 | } | ||
226 | if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) { | ||
227 | die("Not a 32 bit executable\n"); | ||
228 | } | ||
229 | if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) { | ||
230 | die("Not a LSB ELF executable\n"); | ||
231 | } | ||
232 | if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) { | ||
233 | die("Unknown ELF version\n"); | ||
234 | } | ||
235 | /* Convert the fields to native endian */ | ||
236 | ehdr.e_type = elf16_to_cpu(ehdr.e_type); | ||
237 | ehdr.e_machine = elf16_to_cpu(ehdr.e_machine); | ||
238 | ehdr.e_version = elf32_to_cpu(ehdr.e_version); | ||
239 | ehdr.e_entry = elf32_to_cpu(ehdr.e_entry); | ||
240 | ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff); | ||
241 | ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff); | ||
242 | ehdr.e_flags = elf32_to_cpu(ehdr.e_flags); | ||
243 | ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize); | ||
244 | ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize); | ||
245 | ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum); | ||
246 | ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize); | ||
247 | ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum); | ||
248 | ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx); | ||
249 | |||
250 | if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) { | ||
251 | die("Unsupported ELF header type\n"); | ||
252 | } | ||
253 | if (ehdr.e_machine != EM_386) { | ||
254 | die("Not for x86\n"); | ||
255 | } | ||
256 | if (ehdr.e_version != EV_CURRENT) { | ||
257 | die("Unknown ELF version\n"); | ||
258 | } | ||
259 | if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) { | ||
260 | die("Bad Elf header size\n"); | ||
261 | } | ||
262 | if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) { | ||
263 | die("Bad program header entry\n"); | ||
264 | } | ||
265 | if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) { | ||
266 | die("Bad section header entry\n"); | ||
267 | } | ||
268 | if (ehdr.e_shstrndx >= ehdr.e_shnum) { | ||
269 | die("String table index out of bounds\n"); | ||
270 | } | ||
271 | } | ||
272 | |||
273 | static void read_shdrs(FILE *fp) | ||
274 | { | ||
275 | int i; | ||
276 | Elf32_Shdr shdr; | ||
277 | |||
278 | secs = calloc(ehdr.e_shnum, sizeof(struct section)); | ||
279 | if (!secs) { | ||
280 | die("Unable to allocate %d section headers\n", | ||
281 | ehdr.e_shnum); | ||
282 | } | ||
283 | if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) { | ||
284 | die("Seek to %d failed: %s\n", | ||
285 | ehdr.e_shoff, strerror(errno)); | ||
286 | } | ||
287 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
288 | struct section *sec = &secs[i]; | ||
289 | if (fread(&shdr, sizeof shdr, 1, fp) != 1) | ||
290 | die("Cannot read ELF section headers %d/%d: %s\n", | ||
291 | i, ehdr.e_shnum, strerror(errno)); | ||
292 | sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name); | ||
293 | sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type); | ||
294 | sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags); | ||
295 | sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr); | ||
296 | sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset); | ||
297 | sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size); | ||
298 | sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link); | ||
299 | sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info); | ||
300 | sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign); | ||
301 | sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize); | ||
302 | if (sec->shdr.sh_link < ehdr.e_shnum) | ||
303 | sec->link = &secs[sec->shdr.sh_link]; | ||
304 | } | ||
305 | |||
306 | } | ||
307 | |||
308 | static void read_strtabs(FILE *fp) | ||
309 | { | ||
310 | int i; | ||
311 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
312 | struct section *sec = &secs[i]; | ||
313 | if (sec->shdr.sh_type != SHT_STRTAB) { | ||
314 | continue; | ||
315 | } | ||
316 | sec->strtab = malloc(sec->shdr.sh_size); | ||
317 | if (!sec->strtab) { | ||
318 | die("malloc of %d bytes for strtab failed\n", | ||
319 | sec->shdr.sh_size); | ||
320 | } | ||
321 | if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { | ||
322 | die("Seek to %d failed: %s\n", | ||
323 | sec->shdr.sh_offset, strerror(errno)); | ||
324 | } | ||
325 | if (fread(sec->strtab, 1, sec->shdr.sh_size, fp) | ||
326 | != sec->shdr.sh_size) { | ||
327 | die("Cannot read symbol table: %s\n", | ||
328 | strerror(errno)); | ||
329 | } | ||
330 | } | ||
331 | } | ||
332 | |||
333 | static void read_symtabs(FILE *fp) | ||
334 | { | ||
335 | int i,j; | ||
336 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
337 | struct section *sec = &secs[i]; | ||
338 | if (sec->shdr.sh_type != SHT_SYMTAB) { | ||
339 | continue; | ||
340 | } | ||
341 | sec->symtab = malloc(sec->shdr.sh_size); | ||
342 | if (!sec->symtab) { | ||
343 | die("malloc of %d bytes for symtab failed\n", | ||
344 | sec->shdr.sh_size); | ||
345 | } | ||
346 | if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { | ||
347 | die("Seek to %d failed: %s\n", | ||
348 | sec->shdr.sh_offset, strerror(errno)); | ||
349 | } | ||
350 | if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) | ||
351 | != sec->shdr.sh_size) { | ||
352 | die("Cannot read symbol table: %s\n", | ||
353 | strerror(errno)); | ||
354 | } | ||
355 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) { | ||
356 | Elf32_Sym *sym = &sec->symtab[j]; | ||
357 | sym->st_name = elf32_to_cpu(sym->st_name); | ||
358 | sym->st_value = elf32_to_cpu(sym->st_value); | ||
359 | sym->st_size = elf32_to_cpu(sym->st_size); | ||
360 | sym->st_shndx = elf16_to_cpu(sym->st_shndx); | ||
361 | } | ||
362 | } | ||
363 | } | ||
364 | |||
365 | |||
366 | static void read_relocs(FILE *fp) | ||
367 | { | ||
368 | int i,j; | ||
369 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
370 | struct section *sec = &secs[i]; | ||
371 | if (sec->shdr.sh_type != SHT_REL) { | ||
372 | continue; | ||
373 | } | ||
374 | sec->reltab = malloc(sec->shdr.sh_size); | ||
375 | if (!sec->reltab) { | ||
376 | die("malloc of %d bytes for relocs failed\n", | ||
377 | sec->shdr.sh_size); | ||
378 | } | ||
379 | if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { | ||
380 | die("Seek to %d failed: %s\n", | ||
381 | sec->shdr.sh_offset, strerror(errno)); | ||
382 | } | ||
383 | if (fread(sec->reltab, 1, sec->shdr.sh_size, fp) | ||
384 | != sec->shdr.sh_size) { | ||
385 | die("Cannot read symbol table: %s\n", | ||
386 | strerror(errno)); | ||
387 | } | ||
388 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { | ||
389 | Elf32_Rel *rel = &sec->reltab[j]; | ||
390 | rel->r_offset = elf32_to_cpu(rel->r_offset); | ||
391 | rel->r_info = elf32_to_cpu(rel->r_info); | ||
392 | } | ||
393 | } | ||
394 | } | ||
395 | |||
396 | |||
397 | static void print_absolute_symbols(void) | ||
398 | { | ||
399 | int i; | ||
400 | printf("Absolute symbols\n"); | ||
401 | printf(" Num: Value Size Type Bind Visibility Name\n"); | ||
402 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
403 | struct section *sec = &secs[i]; | ||
404 | char *sym_strtab; | ||
405 | Elf32_Sym *sh_symtab; | ||
406 | int j; | ||
407 | |||
408 | if (sec->shdr.sh_type != SHT_SYMTAB) { | ||
409 | continue; | ||
410 | } | ||
411 | sh_symtab = sec->symtab; | ||
412 | sym_strtab = sec->link->strtab; | ||
413 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) { | ||
414 | Elf32_Sym *sym; | ||
415 | const char *name; | ||
416 | sym = &sec->symtab[j]; | ||
417 | name = sym_name(sym_strtab, sym); | ||
418 | if (sym->st_shndx != SHN_ABS) { | ||
419 | continue; | ||
420 | } | ||
421 | printf("%5d %08x %5d %10s %10s %12s %s\n", | ||
422 | j, sym->st_value, sym->st_size, | ||
423 | sym_type(ELF32_ST_TYPE(sym->st_info)), | ||
424 | sym_bind(ELF32_ST_BIND(sym->st_info)), | ||
425 | sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)), | ||
426 | name); | ||
427 | } | ||
428 | } | ||
429 | printf("\n"); | ||
430 | } | ||
431 | |||
432 | static void print_absolute_relocs(void) | ||
433 | { | ||
434 | int i, printed = 0; | ||
435 | |||
436 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
437 | struct section *sec = &secs[i]; | ||
438 | struct section *sec_applies, *sec_symtab; | ||
439 | char *sym_strtab; | ||
440 | Elf32_Sym *sh_symtab; | ||
441 | int j; | ||
442 | if (sec->shdr.sh_type != SHT_REL) { | ||
443 | continue; | ||
444 | } | ||
445 | sec_symtab = sec->link; | ||
446 | sec_applies = &secs[sec->shdr.sh_info]; | ||
447 | if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) { | ||
448 | continue; | ||
449 | } | ||
450 | sh_symtab = sec_symtab->symtab; | ||
451 | sym_strtab = sec_symtab->link->strtab; | ||
452 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { | ||
453 | Elf32_Rel *rel; | ||
454 | Elf32_Sym *sym; | ||
455 | const char *name; | ||
456 | rel = &sec->reltab[j]; | ||
457 | sym = &sh_symtab[ELF32_R_SYM(rel->r_info)]; | ||
458 | name = sym_name(sym_strtab, sym); | ||
459 | if (sym->st_shndx != SHN_ABS) { | ||
460 | continue; | ||
461 | } | ||
462 | |||
463 | /* Absolute symbols are not relocated if bzImage is | ||
464 | * loaded at a non-compiled address. Display a warning | ||
465 | * to user at compile time about the absolute | ||
466 | * relocations present. | ||
467 | * | ||
468 | * User need to audit the code to make sure | ||
469 | * some symbols which should have been section | ||
470 | * relative have not become absolute because of some | ||
471 | * linker optimization or wrong programming usage. | ||
472 | * | ||
473 | * Before warning check if this absolute symbol | ||
474 | * relocation is harmless. | ||
475 | */ | ||
476 | if (is_abs_reloc(name) || is_rel_reloc(name)) | ||
477 | continue; | ||
478 | |||
479 | if (!printed) { | ||
480 | printf("WARNING: Absolute relocations" | ||
481 | " present\n"); | ||
482 | printf("Offset Info Type Sym.Value " | ||
483 | "Sym.Name\n"); | ||
484 | printed = 1; | ||
485 | } | ||
486 | |||
487 | printf("%08x %08x %10s %08x %s\n", | ||
488 | rel->r_offset, | ||
489 | rel->r_info, | ||
490 | rel_type(ELF32_R_TYPE(rel->r_info)), | ||
491 | sym->st_value, | ||
492 | name); | ||
493 | } | ||
494 | } | ||
495 | |||
496 | if (printed) | ||
497 | printf("\n"); | ||
498 | } | ||
499 | |||
500 | static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym)) | ||
501 | { | ||
502 | int i; | ||
503 | /* Walk through the relocations */ | ||
504 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
505 | char *sym_strtab; | ||
506 | Elf32_Sym *sh_symtab; | ||
507 | struct section *sec_applies, *sec_symtab; | ||
508 | int j; | ||
509 | struct section *sec = &secs[i]; | ||
510 | |||
511 | if (sec->shdr.sh_type != SHT_REL) { | ||
512 | continue; | ||
513 | } | ||
514 | sec_symtab = sec->link; | ||
515 | sec_applies = &secs[sec->shdr.sh_info]; | ||
516 | if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) { | ||
517 | continue; | ||
518 | } | ||
519 | sh_symtab = sec_symtab->symtab; | ||
520 | sym_strtab = sec_symtab->link->strtab; | ||
521 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { | ||
522 | Elf32_Rel *rel; | ||
523 | Elf32_Sym *sym; | ||
524 | unsigned r_type; | ||
525 | rel = &sec->reltab[j]; | ||
526 | sym = &sh_symtab[ELF32_R_SYM(rel->r_info)]; | ||
527 | r_type = ELF32_R_TYPE(rel->r_info); | ||
528 | /* Don't visit relocations to absolute symbols */ | ||
529 | if (sym->st_shndx == SHN_ABS && | ||
530 | !is_rel_reloc(sym_name(sym_strtab, sym))) { | ||
531 | continue; | ||
532 | } | ||
533 | switch (r_type) { | ||
534 | case R_386_NONE: | ||
535 | case R_386_PC32: | ||
536 | /* | ||
537 | * NONE can be ignored and and PC relative | ||
538 | * relocations don't need to be adjusted. | ||
539 | */ | ||
540 | break; | ||
541 | case R_386_32: | ||
542 | /* Visit relocations that need to be adjusted */ | ||
543 | visit(rel, sym); | ||
544 | break; | ||
545 | default: | ||
546 | die("Unsupported relocation type: %s (%d)\n", | ||
547 | rel_type(r_type), r_type); | ||
548 | break; | ||
549 | } | ||
550 | } | ||
551 | } | ||
552 | } | ||
553 | |||
554 | static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym) | ||
555 | { | ||
556 | reloc_count += 1; | ||
557 | } | ||
558 | |||
559 | static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym) | ||
560 | { | ||
561 | /* Remember the address that needs to be adjusted. */ | ||
562 | relocs[reloc_idx++] = rel->r_offset; | ||
563 | } | ||
564 | |||
565 | static int cmp_relocs(const void *va, const void *vb) | ||
566 | { | ||
567 | const unsigned long *a, *b; | ||
568 | a = va; b = vb; | ||
569 | return (*a == *b)? 0 : (*a > *b)? 1 : -1; | ||
570 | } | ||
571 | |||
572 | static void emit_relocs(int as_text) | ||
573 | { | ||
574 | int i; | ||
575 | /* Count how many relocations I have and allocate space for them. */ | ||
576 | reloc_count = 0; | ||
577 | walk_relocs(count_reloc); | ||
578 | relocs = malloc(reloc_count * sizeof(relocs[0])); | ||
579 | if (!relocs) { | ||
580 | die("malloc of %d entries for relocs failed\n", | ||
581 | reloc_count); | ||
582 | } | ||
583 | /* Collect up the relocations */ | ||
584 | reloc_idx = 0; | ||
585 | walk_relocs(collect_reloc); | ||
586 | |||
587 | /* Order the relocations for more efficient processing */ | ||
588 | qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs); | ||
589 | |||
590 | /* Print the relocations */ | ||
591 | if (as_text) { | ||
592 | /* Print the relocations in a form suitable that | ||
593 | * gas will like. | ||
594 | */ | ||
595 | printf(".section \".data.reloc\",\"a\"\n"); | ||
596 | printf(".balign 4\n"); | ||
597 | for (i = 0; i < reloc_count; i++) { | ||
598 | printf("\t .long 0x%08lx\n", relocs[i]); | ||
599 | } | ||
600 | printf("\n"); | ||
601 | } | ||
602 | else { | ||
603 | unsigned char buf[4]; | ||
604 | /* Print a stop */ | ||
605 | fwrite("\0\0\0\0", 4, 1, stdout); | ||
606 | /* Now print each relocation */ | ||
607 | for (i = 0; i < reloc_count; i++) { | ||
608 | buf[0] = (relocs[i] >> 0) & 0xff; | ||
609 | buf[1] = (relocs[i] >> 8) & 0xff; | ||
610 | buf[2] = (relocs[i] >> 16) & 0xff; | ||
611 | buf[3] = (relocs[i] >> 24) & 0xff; | ||
612 | fwrite(buf, 4, 1, stdout); | ||
613 | } | ||
614 | } | ||
615 | } | ||
616 | |||
617 | static void usage(void) | ||
618 | { | ||
619 | die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n"); | ||
620 | } | ||
621 | |||
622 | int main(int argc, char **argv) | ||
623 | { | ||
624 | int show_absolute_syms, show_absolute_relocs; | ||
625 | int as_text; | ||
626 | const char *fname; | ||
627 | FILE *fp; | ||
628 | int i; | ||
629 | |||
630 | regex_init(); | ||
631 | |||
632 | show_absolute_syms = 0; | ||
633 | show_absolute_relocs = 0; | ||
634 | as_text = 0; | ||
635 | fname = NULL; | ||
636 | for (i = 1; i < argc; i++) { | ||
637 | char *arg = argv[i]; | ||
638 | if (*arg == '-') { | ||
639 | if (strcmp(argv[1], "--abs-syms") == 0) { | ||
640 | show_absolute_syms = 1; | ||
641 | continue; | ||
642 | } | ||
643 | |||
644 | if (strcmp(argv[1], "--abs-relocs") == 0) { | ||
645 | show_absolute_relocs = 1; | ||
646 | continue; | ||
647 | } | ||
648 | else if (strcmp(argv[1], "--text") == 0) { | ||
649 | as_text = 1; | ||
650 | continue; | ||
651 | } | ||
652 | } | ||
653 | else if (!fname) { | ||
654 | fname = arg; | ||
655 | continue; | ||
656 | } | ||
657 | usage(); | ||
658 | } | ||
659 | if (!fname) { | ||
660 | usage(); | ||
661 | } | ||
662 | fp = fopen(fname, "r"); | ||
663 | if (!fp) { | ||
664 | die("Cannot open %s: %s\n", | ||
665 | fname, strerror(errno)); | ||
666 | } | ||
667 | read_ehdr(fp); | ||
668 | read_shdrs(fp); | ||
669 | read_strtabs(fp); | ||
670 | read_symtabs(fp); | ||
671 | read_relocs(fp); | ||
672 | if (show_absolute_syms) { | ||
673 | print_absolute_symbols(); | ||
674 | return 0; | ||
675 | } | ||
676 | if (show_absolute_relocs) { | ||
677 | print_absolute_relocs(); | ||
678 | return 0; | ||
679 | } | ||
680 | emit_relocs(as_text); | ||
681 | return 0; | ||
682 | } | ||