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Linux 3.12.28
[linux/fpc-iii.git] / arch / x86 / tools / relocs.c
blobf7bab68a4b83e4094db9b70c50292fddd88098c1
1 /* This is included from relocs_32/64.c */
2
3 #define ElfW(type) _ElfW(ELF_BITS, type)
4 #define _ElfW(bits, type) __ElfW(bits, type)
5 #define __ElfW(bits, type) Elf##bits##_##type
6
7 #define Elf_Addr ElfW(Addr)
8 #define Elf_Ehdr ElfW(Ehdr)
9 #define Elf_Phdr ElfW(Phdr)
10 #define Elf_Shdr ElfW(Shdr)
11 #define Elf_Sym ElfW(Sym)
12
13 static Elf_Ehdr ehdr;
14
15 struct relocs {
16 uint32_t *offset;
17 unsigned long count;
18 unsigned long size;
19 };
20
21 static struct relocs relocs16;
22 static struct relocs relocs32;
23 static struct relocs relocs64;
24
25 struct section {
26 Elf_Shdr shdr;
27 struct section *link;
28 Elf_Sym *symtab;
29 Elf_Rel *reltab;
30 char *strtab;
31 };
32 static struct section *secs;
33
34 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
35 /*
36 * Following symbols have been audited. There values are constant and do
37 * not change if bzImage is loaded at a different physical address than
38 * the address for which it has been compiled. Don't warn user about
39 * absolute relocations present w.r.t these symbols.
40 */
41 [S_ABS] =
42 "^(xen_irq_disable_direct_reloc$|"
43 "xen_save_fl_direct_reloc$|"
44 "VDSO|"
45 "__crc_)",
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 [S_REL] =
52 "^(__init_(begin|end)|"
53 "__x86_cpu_dev_(start|end)|"
54 "(__parainstructions|__alt_instructions)(|_end)|"
55 "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
56 "__(start|end)_pci_.*|"
57 "__(start|end)_builtin_fw|"
58 "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
59 "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
60 "__(start|stop)___param|"
61 "__(start|stop)___modver|"
62 "__(start|stop)___bug_table|"
63 "__tracedata_(start|end)|"
64 "__(start|stop)_notes|"
65 "__end_rodata|"
66 "__initramfs_start|"
67 "(jiffies|jiffies_64)|"
68 #if ELF_BITS == 64
69 "__per_cpu_load|"
70 "init_per_cpu__.*|"
71 "__end_rodata_hpage_align|"
72 "__vvar_page|"
73 #endif
74 "_end)$"
75 };
76
77
78 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
79 /*
80 * These symbols are known to be relative, even if the linker marks them
81 * as absolute (typically defined outside any section in the linker script.)
82 */
83 [S_REL] =
84 "^pa_",
85
86 /*
87 * These are 16-bit segment symbols when compiling 16-bit code.
88 */
89 [S_SEG] =
90 "^real_mode_seg$",
91
92 /*
93 * These are offsets belonging to segments, as opposed to linear addresses,
94 * when compiling 16-bit code.
95 */
96 [S_LIN] =
97 "^pa_",
98 };
99
100 static const char * const *sym_regex;
101
102 static regex_t sym_regex_c[S_NSYMTYPES];
103 static int is_reloc(enum symtype type, const char *sym_name)
104 {
105 return sym_regex[type] &&
106 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
107 }
108
109 static void regex_init(int use_real_mode)
110 {
111 char errbuf[128];
112 int err;
113 int i;
114
115 if (use_real_mode)
116 sym_regex = sym_regex_realmode;
117 else
118 sym_regex = sym_regex_kernel;
119
120 for (i = 0; i < S_NSYMTYPES; i++) {
121 if (!sym_regex[i])
122 continue;
123
124 err = regcomp(&sym_regex_c[i], sym_regex[i],
125 REG_EXTENDED|REG_NOSUB);
126
127 if (err) {
128 regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
129 die("%s", errbuf);
130 }
131 }
132 }
133
134 static const char *sym_type(unsigned type)
135 {
136 static const char *type_name[] = {
137 #define SYM_TYPE(X) [X] = #X
138 SYM_TYPE(STT_NOTYPE),
139 SYM_TYPE(STT_OBJECT),
140 SYM_TYPE(STT_FUNC),
141 SYM_TYPE(STT_SECTION),
142 SYM_TYPE(STT_FILE),
143 SYM_TYPE(STT_COMMON),
144 SYM_TYPE(STT_TLS),
145 #undef SYM_TYPE
146 };
147 const char *name = "unknown sym type name";
148 if (type < ARRAY_SIZE(type_name)) {
149 name = type_name[type];
150 }
151 return name;
152 }
153
154 static const char *sym_bind(unsigned bind)
155 {
156 static const char *bind_name[] = {
157 #define SYM_BIND(X) [X] = #X
158 SYM_BIND(STB_LOCAL),
159 SYM_BIND(STB_GLOBAL),
160 SYM_BIND(STB_WEAK),
161 #undef SYM_BIND
162 };
163 const char *name = "unknown sym bind name";
164 if (bind < ARRAY_SIZE(bind_name)) {
165 name = bind_name[bind];
166 }
167 return name;
168 }
169
170 static const char *sym_visibility(unsigned visibility)
171 {
172 static const char *visibility_name[] = {
173 #define SYM_VISIBILITY(X) [X] = #X
174 SYM_VISIBILITY(STV_DEFAULT),
175 SYM_VISIBILITY(STV_INTERNAL),
176 SYM_VISIBILITY(STV_HIDDEN),
177 SYM_VISIBILITY(STV_PROTECTED),
178 #undef SYM_VISIBILITY
179 };
180 const char *name = "unknown sym visibility name";
181 if (visibility < ARRAY_SIZE(visibility_name)) {
182 name = visibility_name[visibility];
183 }
184 return name;
185 }
186
187 static const char *rel_type(unsigned type)
188 {
189 static const char *type_name[] = {
190 #define REL_TYPE(X) [X] = #X
191 #if ELF_BITS == 64
192 REL_TYPE(R_X86_64_NONE),
193 REL_TYPE(R_X86_64_64),
194 REL_TYPE(R_X86_64_PC32),
195 REL_TYPE(R_X86_64_GOT32),
196 REL_TYPE(R_X86_64_PLT32),
197 REL_TYPE(R_X86_64_COPY),
198 REL_TYPE(R_X86_64_GLOB_DAT),
199 REL_TYPE(R_X86_64_JUMP_SLOT),
200 REL_TYPE(R_X86_64_RELATIVE),
201 REL_TYPE(R_X86_64_GOTPCREL),
202 REL_TYPE(R_X86_64_32),
203 REL_TYPE(R_X86_64_32S),
204 REL_TYPE(R_X86_64_16),
205 REL_TYPE(R_X86_64_PC16),
206 REL_TYPE(R_X86_64_8),
207 REL_TYPE(R_X86_64_PC8),
208 #else
209 REL_TYPE(R_386_NONE),
210 REL_TYPE(R_386_32),
211 REL_TYPE(R_386_PC32),
212 REL_TYPE(R_386_GOT32),
213 REL_TYPE(R_386_PLT32),
214 REL_TYPE(R_386_COPY),
215 REL_TYPE(R_386_GLOB_DAT),
216 REL_TYPE(R_386_JMP_SLOT),
217 REL_TYPE(R_386_RELATIVE),
218 REL_TYPE(R_386_GOTOFF),
219 REL_TYPE(R_386_GOTPC),
220 REL_TYPE(R_386_8),
221 REL_TYPE(R_386_PC8),
222 REL_TYPE(R_386_16),
223 REL_TYPE(R_386_PC16),
224 #endif
225 #undef REL_TYPE
226 };
227 const char *name = "unknown type rel type name";
228 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
229 name = type_name[type];
230 }
231 return name;
232 }
233
234 static const char *sec_name(unsigned shndx)
235 {
236 const char *sec_strtab;
237 const char *name;
238 sec_strtab = secs[ehdr.e_shstrndx].strtab;
239 name = "<noname>";
240 if (shndx < ehdr.e_shnum) {
241 name = sec_strtab + secs[shndx].shdr.sh_name;
242 }
243 else if (shndx == SHN_ABS) {
244 name = "ABSOLUTE";
245 }
246 else if (shndx == SHN_COMMON) {
247 name = "COMMON";
248 }
249 return name;
250 }
251
252 static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
253 {
254 const char *name;
255 name = "<noname>";
256 if (sym->st_name) {
257 name = sym_strtab + sym->st_name;
258 }
259 else {
260 name = sec_name(sym->st_shndx);
261 }
262 return name;
263 }
264
265 static Elf_Sym *sym_lookup(const char *symname)
266 {
267 int i;
268 for (i = 0; i < ehdr.e_shnum; i++) {
269 struct section *sec = &secs[i];
270 long nsyms;
271 char *strtab;
272 Elf_Sym *symtab;
273 Elf_Sym *sym;
274
275 if (sec->shdr.sh_type != SHT_SYMTAB)
276 continue;
277
278 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
279 symtab = sec->symtab;
280 strtab = sec->link->strtab;
281
282 for (sym = symtab; --nsyms >= 0; sym++) {
283 if (!sym->st_name)
284 continue;
285 if (strcmp(symname, strtab + sym->st_name) == 0)
286 return sym;
287 }
288 }
289 return 0;
290 }
291
292 #if BYTE_ORDER == LITTLE_ENDIAN
293 #define le16_to_cpu(val) (val)
294 #define le32_to_cpu(val) (val)
295 #define le64_to_cpu(val) (val)
296 #endif
297 #if BYTE_ORDER == BIG_ENDIAN
298 #define le16_to_cpu(val) bswap_16(val)
299 #define le32_to_cpu(val) bswap_32(val)
300 #define le64_to_cpu(val) bswap_64(val)
301 #endif
302
303 static uint16_t elf16_to_cpu(uint16_t val)
304 {
305 return le16_to_cpu(val);
306 }
307
308 static uint32_t elf32_to_cpu(uint32_t val)
309 {
310 return le32_to_cpu(val);
311 }
312
313 #define elf_half_to_cpu(x) elf16_to_cpu(x)
314 #define elf_word_to_cpu(x) elf32_to_cpu(x)
315
316 #if ELF_BITS == 64
317 static uint64_t elf64_to_cpu(uint64_t val)
318 {
319 return le64_to_cpu(val);
320 }
321 #define elf_addr_to_cpu(x) elf64_to_cpu(x)
322 #define elf_off_to_cpu(x) elf64_to_cpu(x)
323 #define elf_xword_to_cpu(x) elf64_to_cpu(x)
324 #else
325 #define elf_addr_to_cpu(x) elf32_to_cpu(x)
326 #define elf_off_to_cpu(x) elf32_to_cpu(x)
327 #define elf_xword_to_cpu(x) elf32_to_cpu(x)
328 #endif
329
330 static void read_ehdr(FILE *fp)
331 {
332 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
333 die("Cannot read ELF header: %s\n",
334 strerror(errno));
335 }
336 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
337 die("No ELF magic\n");
338 }
339 if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
340 die("Not a %d bit executable\n", ELF_BITS);
341 }
342 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
343 die("Not a LSB ELF executable\n");
344 }
345 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
346 die("Unknown ELF version\n");
347 }
348 /* Convert the fields to native endian */
349 ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
350 ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
351 ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
352 ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
353 ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
354 ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
355 ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
356 ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
357 ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
358 ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
359 ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
360 ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
361 ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
362
363 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
364 die("Unsupported ELF header type\n");
365 }
366 if (ehdr.e_machine != ELF_MACHINE) {
367 die("Not for %s\n", ELF_MACHINE_NAME);
368 }
369 if (ehdr.e_version != EV_CURRENT) {
370 die("Unknown ELF version\n");
371 }
372 if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
373 die("Bad Elf header size\n");
374 }
375 if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
376 die("Bad program header entry\n");
377 }
378 if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
379 die("Bad section header entry\n");
380 }
381 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
382 die("String table index out of bounds\n");
383 }
384 }
385
386 static void read_shdrs(FILE *fp)
387 {
388 int i;
389 Elf_Shdr shdr;
390
391 secs = calloc(ehdr.e_shnum, sizeof(struct section));
392 if (!secs) {
393 die("Unable to allocate %d section headers\n",
394 ehdr.e_shnum);
395 }
396 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
397 die("Seek to %d failed: %s\n",
398 ehdr.e_shoff, strerror(errno));
399 }
400 for (i = 0; i < ehdr.e_shnum; i++) {
401 struct section *sec = &secs[i];
402 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
403 die("Cannot read ELF section headers %d/%d: %s\n",
404 i, ehdr.e_shnum, strerror(errno));
405 sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
406 sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
407 sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
408 sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
409 sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
410 sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
411 sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
412 sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
413 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
414 sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
415 if (sec->shdr.sh_link < ehdr.e_shnum)
416 sec->link = &secs[sec->shdr.sh_link];
417 }
418
419 }
420
421 static void read_strtabs(FILE *fp)
422 {
423 int i;
424 for (i = 0; i < ehdr.e_shnum; i++) {
425 struct section *sec = &secs[i];
426 if (sec->shdr.sh_type != SHT_STRTAB) {
427 continue;
428 }
429 sec->strtab = malloc(sec->shdr.sh_size);
430 if (!sec->strtab) {
431 die("malloc of %d bytes for strtab failed\n",
432 sec->shdr.sh_size);
433 }
434 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
435 die("Seek to %d failed: %s\n",
436 sec->shdr.sh_offset, strerror(errno));
437 }
438 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
439 != sec->shdr.sh_size) {
440 die("Cannot read symbol table: %s\n",
441 strerror(errno));
442 }
443 }
444 }
445
446 static void read_symtabs(FILE *fp)
447 {
448 int i,j;
449 for (i = 0; i < ehdr.e_shnum; i++) {
450 struct section *sec = &secs[i];
451 if (sec->shdr.sh_type != SHT_SYMTAB) {
452 continue;
453 }
454 sec->symtab = malloc(sec->shdr.sh_size);
455 if (!sec->symtab) {
456 die("malloc of %d bytes for symtab failed\n",
457 sec->shdr.sh_size);
458 }
459 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
460 die("Seek to %d failed: %s\n",
461 sec->shdr.sh_offset, strerror(errno));
462 }
463 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
464 != sec->shdr.sh_size) {
465 die("Cannot read symbol table: %s\n",
466 strerror(errno));
467 }
468 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
469 Elf_Sym *sym = &sec->symtab[j];
470 sym->st_name = elf_word_to_cpu(sym->st_name);
471 sym->st_value = elf_addr_to_cpu(sym->st_value);
472 sym->st_size = elf_xword_to_cpu(sym->st_size);
473 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
474 }
475 }
476 }
477
478
479 static void read_relocs(FILE *fp)
480 {
481 int i,j;
482 for (i = 0; i < ehdr.e_shnum; i++) {
483 struct section *sec = &secs[i];
484 if (sec->shdr.sh_type != SHT_REL_TYPE) {
485 continue;
486 }
487 sec->reltab = malloc(sec->shdr.sh_size);
488 if (!sec->reltab) {
489 die("malloc of %d bytes for relocs failed\n",
490 sec->shdr.sh_size);
491 }
492 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
493 die("Seek to %d failed: %s\n",
494 sec->shdr.sh_offset, strerror(errno));
495 }
496 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
497 != sec->shdr.sh_size) {
498 die("Cannot read symbol table: %s\n",
499 strerror(errno));
500 }
501 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
502 Elf_Rel *rel = &sec->reltab[j];
503 rel->r_offset = elf_addr_to_cpu(rel->r_offset);
504 rel->r_info = elf_xword_to_cpu(rel->r_info);
505 #if (SHT_REL_TYPE == SHT_RELA)
506 rel->r_addend = elf_xword_to_cpu(rel->r_addend);
507 #endif
508 }
509 }
510 }
511
512
513 static void print_absolute_symbols(void)
514 {
515 int i;
516 const char *format;
517
518 if (ELF_BITS == 64)
519 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
520 else
521 format = "%5d %08"PRIx32" %5"PRId32" %10s %10s %12s %s\n";
522
523 printf("Absolute symbols\n");
524 printf(" Num: Value Size Type Bind Visibility Name\n");
525 for (i = 0; i < ehdr.e_shnum; i++) {
526 struct section *sec = &secs[i];
527 char *sym_strtab;
528 int j;
529
530 if (sec->shdr.sh_type != SHT_SYMTAB) {
531 continue;
532 }
533 sym_strtab = sec->link->strtab;
534 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
535 Elf_Sym *sym;
536 const char *name;
537 sym = &sec->symtab[j];
538 name = sym_name(sym_strtab, sym);
539 if (sym->st_shndx != SHN_ABS) {
540 continue;
541 }
542 printf(format,
543 j, sym->st_value, sym->st_size,
544 sym_type(ELF_ST_TYPE(sym->st_info)),
545 sym_bind(ELF_ST_BIND(sym->st_info)),
546 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
547 name);
548 }
549 }
550 printf("\n");
551 }
552
553 static void print_absolute_relocs(void)
554 {
555 int i, printed = 0;
556 const char *format;
557
558 if (ELF_BITS == 64)
559 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64" %s\n";
560 else
561 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
562
563 for (i = 0; i < ehdr.e_shnum; i++) {
564 struct section *sec = &secs[i];
565 struct section *sec_applies, *sec_symtab;
566 char *sym_strtab;
567 Elf_Sym *sh_symtab;
568 int j;
569 if (sec->shdr.sh_type != SHT_REL_TYPE) {
570 continue;
571 }
572 sec_symtab = sec->link;
573 sec_applies = &secs[sec->shdr.sh_info];
574 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
575 continue;
576 }
577 sh_symtab = sec_symtab->symtab;
578 sym_strtab = sec_symtab->link->strtab;
579 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
580 Elf_Rel *rel;
581 Elf_Sym *sym;
582 const char *name;
583 rel = &sec->reltab[j];
584 sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
585 name = sym_name(sym_strtab, sym);
586 if (sym->st_shndx != SHN_ABS) {
587 continue;
588 }
589
590 /* Absolute symbols are not relocated if bzImage is
591 * loaded at a non-compiled address. Display a warning
592 * to user at compile time about the absolute
593 * relocations present.
594 *
595 * User need to audit the code to make sure
596 * some symbols which should have been section
597 * relative have not become absolute because of some
598 * linker optimization or wrong programming usage.
599 *
600 * Before warning check if this absolute symbol
601 * relocation is harmless.
602 */
603 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
604 continue;
605
606 if (!printed) {
607 printf("WARNING: Absolute relocations"
608 " present\n");
609 printf("Offset Info Type Sym.Value "
610 "Sym.Name\n");
611 printed = 1;
612 }
613
614 printf(format,
615 rel->r_offset,
616 rel->r_info,
617 rel_type(ELF_R_TYPE(rel->r_info)),
618 sym->st_value,
619 name);
620 }
621 }
622
623 if (printed)
624 printf("\n");
625 }
626
627 static void add_reloc(struct relocs *r, uint32_t offset)
628 {
629 if (r->count == r->size) {
630 unsigned long newsize = r->size + 50000;
631 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
632
633 if (!mem)
634 die("realloc of %ld entries for relocs failed\n",
635 newsize);
636 r->offset = mem;
637 r->size = newsize;
638 }
639 r->offset[r->count++] = offset;
640 }
641
642 static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
643 Elf_Sym *sym, const char *symname))
644 {
645 int i;
646 /* Walk through the relocations */
647 for (i = 0; i < ehdr.e_shnum; i++) {
648 char *sym_strtab;
649 Elf_Sym *sh_symtab;
650 struct section *sec_applies, *sec_symtab;
651 int j;
652 struct section *sec = &secs[i];
653
654 if (sec->shdr.sh_type != SHT_REL_TYPE) {
655 continue;
656 }
657 sec_symtab = sec->link;
658 sec_applies = &secs[sec->shdr.sh_info];
659 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
660 continue;
661 }
662 sh_symtab = sec_symtab->symtab;
663 sym_strtab = sec_symtab->link->strtab;
664 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
665 Elf_Rel *rel = &sec->reltab[j];
666 Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
667 const char *symname = sym_name(sym_strtab, sym);
668
669 process(sec, rel, sym, symname);
670 }
671 }
672 }
673
674 /*
675 * The .data..percpu section is a special case for x86_64 SMP kernels.
676 * It is used to initialize the actual per_cpu areas and to provide
677 * definitions for the per_cpu variables that correspond to their offsets
678 * within the percpu area. Since the values of all of the symbols need
679 * to be offsets from the start of the per_cpu area the virtual address
680 * (sh_addr) of .data..percpu is 0 in SMP kernels.
681 *
682 * This means that:
683 *
684 * Relocations that reference symbols in the per_cpu area do not
685 * need further relocation (since the value is an offset relative
686 * to the start of the per_cpu area that does not change).
687 *
688 * Relocations that apply to the per_cpu area need to have their
689 * offset adjusted by by the value of __per_cpu_load to make them
690 * point to the correct place in the loaded image (because the
691 * virtual address of .data..percpu is 0).
692 *
693 * For non SMP kernels .data..percpu is linked as part of the normal
694 * kernel data and does not require special treatment.
695 *
696 */
697 static int per_cpu_shndx = -1;
698 Elf_Addr per_cpu_load_addr;
699
700 static void percpu_init(void)
701 {
702 int i;
703 for (i = 0; i < ehdr.e_shnum; i++) {
704 ElfW(Sym) *sym;
705 if (strcmp(sec_name(i), ".data..percpu"))
706 continue;
707
708 if (secs[i].shdr.sh_addr != 0) /* non SMP kernel */
709 return;
710
711 sym = sym_lookup("__per_cpu_load");
712 if (!sym)
713 die("can't find __per_cpu_load\n");
714
715 per_cpu_shndx = i;
716 per_cpu_load_addr = sym->st_value;
717 return;
718 }
719 }
720
721 #if ELF_BITS == 64
722
723 /*
724 * Check to see if a symbol lies in the .data..percpu section.
725 * For some as yet not understood reason the "__init_begin"
726 * symbol which immediately preceeds the .data..percpu section
727 * also shows up as it it were part of it so we do an explict
728 * check for that symbol name and ignore it.
729 */
730 static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
731 {
732 return (sym->st_shndx == per_cpu_shndx) &&
733 strcmp(symname, "__init_begin");
734 }
735
736
737 static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
738 const char *symname)
739 {
740 unsigned r_type = ELF64_R_TYPE(rel->r_info);
741 ElfW(Addr) offset = rel->r_offset;
742 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
743
744 if (sym->st_shndx == SHN_UNDEF)
745 return 0;
746
747 /*
748 * Adjust the offset if this reloc applies to the percpu section.
749 */
750 if (sec->shdr.sh_info == per_cpu_shndx)
751 offset += per_cpu_load_addr;
752
753 switch (r_type) {
754 case R_X86_64_NONE:
755 case R_X86_64_PC32:
756 /*
757 * NONE can be ignored and PC relative relocations don't
758 * need to be adjusted.
759 */
760 break;
761
762 case R_X86_64_32:
763 case R_X86_64_32S:
764 case R_X86_64_64:
765 /*
766 * References to the percpu area don't need to be adjusted.
767 */
768 if (is_percpu_sym(sym, symname))
769 break;
770
771 if (shn_abs) {
772 /*
773 * Whitelisted absolute symbols do not require
774 * relocation.
775 */
776 if (is_reloc(S_ABS, symname))
777 break;
778
779 die("Invalid absolute %s relocation: %s\n",
780 rel_type(r_type), symname);
781 break;
782 }
783
784 /*
785 * Relocation offsets for 64 bit kernels are output
786 * as 32 bits and sign extended back to 64 bits when
787 * the relocations are processed.
788 * Make sure that the offset will fit.
789 */
790 if ((int32_t)offset != (int64_t)offset)
791 die("Relocation offset doesn't fit in 32 bits\n");
792
793 if (r_type == R_X86_64_64)
794 add_reloc(&relocs64, offset);
795 else
796 add_reloc(&relocs32, offset);
797 break;
798
799 default:
800 die("Unsupported relocation type: %s (%d)\n",
801 rel_type(r_type), r_type);
802 break;
803 }
804
805 return 0;
806 }
807
808 #else
809
810 static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
811 const char *symname)
812 {
813 unsigned r_type = ELF32_R_TYPE(rel->r_info);
814 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
815
816 switch (r_type) {
817 case R_386_NONE:
818 case R_386_PC32:
819 case R_386_PC16:
820 case R_386_PC8:
821 /*
822 * NONE can be ignored and PC relative relocations don't
823 * need to be adjusted.
824 */
825 break;
826
827 case R_386_32:
828 if (shn_abs) {
829 /*
830 * Whitelisted absolute symbols do not require
831 * relocation.
832 */
833 if (is_reloc(S_ABS, symname))
834 break;
835
836 die("Invalid absolute %s relocation: %s\n",
837 rel_type(r_type), symname);
838 break;
839 }
840
841 add_reloc(&relocs32, rel->r_offset);
842 break;
843
844 default:
845 die("Unsupported relocation type: %s (%d)\n",
846 rel_type(r_type), r_type);
847 break;
848 }
849
850 return 0;
851 }
852
853 static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
854 const char *symname)
855 {
856 unsigned r_type = ELF32_R_TYPE(rel->r_info);
857 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
858
859 switch (r_type) {
860 case R_386_NONE:
861 case R_386_PC32:
862 case R_386_PC16:
863 case R_386_PC8:
864 /*
865 * NONE can be ignored and PC relative relocations don't
866 * need to be adjusted.
867 */
868 break;
869
870 case R_386_16:
871 if (shn_abs) {
872 /*
873 * Whitelisted absolute symbols do not require
874 * relocation.
875 */
876 if (is_reloc(S_ABS, symname))
877 break;
878
879 if (is_reloc(S_SEG, symname)) {
880 add_reloc(&relocs16, rel->r_offset);
881 break;
882 }
883 } else {
884 if (!is_reloc(S_LIN, symname))
885 break;
886 }
887 die("Invalid %s %s relocation: %s\n",
888 shn_abs ? "absolute" : "relative",
889 rel_type(r_type), symname);
890 break;
891
892 case R_386_32:
893 if (shn_abs) {
894 /*
895 * Whitelisted absolute symbols do not require
896 * relocation.
897 */
898 if (is_reloc(S_ABS, symname))
899 break;
900
901 if (is_reloc(S_REL, symname)) {
902 add_reloc(&relocs32, rel->r_offset);
903 break;
904 }
905 } else {
906 if (is_reloc(S_LIN, symname))
907 add_reloc(&relocs32, rel->r_offset);
908 break;
909 }
910 die("Invalid %s %s relocation: %s\n",
911 shn_abs ? "absolute" : "relative",
912 rel_type(r_type), symname);
913 break;
914
915 default:
916 die("Unsupported relocation type: %s (%d)\n",
917 rel_type(r_type), r_type);
918 break;
919 }
920
921 return 0;
922 }
923
924 #endif
925
926 static int cmp_relocs(const void *va, const void *vb)
927 {
928 const uint32_t *a, *b;
929 a = va; b = vb;
930 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
931 }
932
933 static void sort_relocs(struct relocs *r)
934 {
935 qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
936 }
937
938 static int write32(uint32_t v, FILE *f)
939 {
940 unsigned char buf[4];
941
942 put_unaligned_le32(v, buf);
943 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
944 }
945
946 static int write32_as_text(uint32_t v, FILE *f)
947 {
948 return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
949 }
950
951 static void emit_relocs(int as_text, int use_real_mode)
952 {
953 int i;
954 int (*write_reloc)(uint32_t, FILE *) = write32;
955 int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
956 const char *symname);
957
958 #if ELF_BITS == 64
959 if (!use_real_mode)
960 do_reloc = do_reloc64;
961 else
962 die("--realmode not valid for a 64-bit ELF file");
963 #else
964 if (!use_real_mode)
965 do_reloc = do_reloc32;
966 else
967 do_reloc = do_reloc_real;
968 #endif
969
970 /* Collect up the relocations */
971 walk_relocs(do_reloc);
972
973 if (relocs16.count && !use_real_mode)
974 die("Segment relocations found but --realmode not specified\n");
975
976 /* Order the relocations for more efficient processing */
977 sort_relocs(&relocs16);
978 sort_relocs(&relocs32);
979 sort_relocs(&relocs64);
980
981 /* Print the relocations */
982 if (as_text) {
983 /* Print the relocations in a form suitable that
984 * gas will like.
985 */
986 printf(".section \".data.reloc\",\"a\"\n");
987 printf(".balign 4\n");
988 write_reloc = write32_as_text;
989 }
990
991 if (use_real_mode) {
992 write_reloc(relocs16.count, stdout);
993 for (i = 0; i < relocs16.count; i++)
994 write_reloc(relocs16.offset[i], stdout);
995
996 write_reloc(relocs32.count, stdout);
997 for (i = 0; i < relocs32.count; i++)
998 write_reloc(relocs32.offset[i], stdout);
999 } else {
1000 if (ELF_BITS == 64) {
1001 /* Print a stop */
1002 write_reloc(0, stdout);
1003
1004 /* Now print each relocation */
1005 for (i = 0; i < relocs64.count; i++)
1006 write_reloc(relocs64.offset[i], stdout);
1007 }
1008
1009 /* Print a stop */
1010 write_reloc(0, stdout);
1011
1012 /* Now print each relocation */
1013 for (i = 0; i < relocs32.count; i++)
1014 write_reloc(relocs32.offset[i], stdout);
1015 }
1016 }
1017
1018 #if ELF_BITS == 64
1019 # define process process_64
1020 #else
1021 # define process process_32
1022 #endif
1023
1024 void process(FILE *fp, int use_real_mode, int as_text,
1025 int show_absolute_syms, int show_absolute_relocs)
1026 {
1027 regex_init(use_real_mode);
1028 read_ehdr(fp);
1029 read_shdrs(fp);
1030 read_strtabs(fp);
1031 read_symtabs(fp);
1032 read_relocs(fp);
1033 if (ELF_BITS == 64)
1034 percpu_init();
1035 if (show_absolute_syms) {
1036 print_absolute_symbols();
1037 return;
1038 }
1039 if (show_absolute_relocs) {
1040 print_absolute_relocs();
1041 return;
1042 }
1043 emit_relocs(as_text, use_real_mode);
1044 }
Linux with added FPC-III support