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Linux 4.9.243
[linux/fpc-iii.git] / arch / x86 / tools / relocs.c
blob5b6c8486a0bece83fe9af6248537675d41f9a3ac
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 #if ELF_BITS == 64
24 static struct relocs relocs32neg;
25 static struct relocs relocs64;
26 #endif
27
28 struct section {
29 Elf_Shdr shdr;
30 struct section *link;
31 Elf_Sym *symtab;
32 Elf_Rel *reltab;
33 char *strtab;
34 };
35 static struct section *secs;
36
37 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
38 /*
39 * Following symbols have been audited. There values are constant and do
40 * not change if bzImage is loaded at a different physical address than
41 * the address for which it has been compiled. Don't warn user about
42 * absolute relocations present w.r.t these symbols.
43 */
44 [S_ABS] =
45 "^(xen_irq_disable_direct_reloc$|"
46 "xen_save_fl_direct_reloc$|"
47 "VDSO|"
48 "__crc_)",
49
50 /*
51 * These symbols are known to be relative, even if the linker marks them
52 * as absolute (typically defined outside any section in the linker script.)
53 */
54 [S_REL] =
55 "^(__init_(begin|end)|"
56 "__x86_cpu_dev_(start|end)|"
57 "(__parainstructions|__alt_instructions)(|_end)|"
58 "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
59 "__(start|end)_pci_.*|"
60 "__(start|end)_builtin_fw|"
61 "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
62 "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
63 "__(start|stop)___param|"
64 "__(start|stop)___modver|"
65 "__(start|stop)___bug_table|"
66 "__tracedata_(start|end)|"
67 "__(start|stop)_notes|"
68 "__end_rodata|"
69 "__initramfs_start|"
70 "(jiffies|jiffies_64)|"
71 #if ELF_BITS == 64
72 "__per_cpu_load|"
73 "init_per_cpu__.*|"
74 "__end_rodata_hpage_align|"
75 #endif
76 "__vvar_page|"
77 "_end)$"
78 };
79
80
81 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
82 /*
83 * These symbols are known to be relative, even if the linker marks them
84 * as absolute (typically defined outside any section in the linker script.)
85 */
86 [S_REL] =
87 "^pa_",
88
89 /*
90 * These are 16-bit segment symbols when compiling 16-bit code.
91 */
92 [S_SEG] =
93 "^real_mode_seg$",
94
95 /*
96 * These are offsets belonging to segments, as opposed to linear addresses,
97 * when compiling 16-bit code.
98 */
99 [S_LIN] =
100 "^pa_",
101 };
102
103 static const char * const *sym_regex;
104
105 static regex_t sym_regex_c[S_NSYMTYPES];
106 static int is_reloc(enum symtype type, const char *sym_name)
107 {
108 return sym_regex[type] &&
109 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
110 }
111
112 static void regex_init(int use_real_mode)
113 {
114 char errbuf[128];
115 int err;
116 int i;
117
118 if (use_real_mode)
119 sym_regex = sym_regex_realmode;
120 else
121 sym_regex = sym_regex_kernel;
122
123 for (i = 0; i < S_NSYMTYPES; i++) {
124 if (!sym_regex[i])
125 continue;
126
127 err = regcomp(&sym_regex_c[i], sym_regex[i],
128 REG_EXTENDED|REG_NOSUB);
129
130 if (err) {
131 regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
132 die("%s", errbuf);
133 }
134 }
135 }
136
137 static const char *sym_type(unsigned type)
138 {
139 static const char *type_name[] = {
140 #define SYM_TYPE(X) [X] = #X
141 SYM_TYPE(STT_NOTYPE),
142 SYM_TYPE(STT_OBJECT),
143 SYM_TYPE(STT_FUNC),
144 SYM_TYPE(STT_SECTION),
145 SYM_TYPE(STT_FILE),
146 SYM_TYPE(STT_COMMON),
147 SYM_TYPE(STT_TLS),
148 #undef SYM_TYPE
149 };
150 const char *name = "unknown sym type name";
151 if (type < ARRAY_SIZE(type_name)) {
152 name = type_name[type];
153 }
154 return name;
155 }
156
157 static const char *sym_bind(unsigned bind)
158 {
159 static const char *bind_name[] = {
160 #define SYM_BIND(X) [X] = #X
161 SYM_BIND(STB_LOCAL),
162 SYM_BIND(STB_GLOBAL),
163 SYM_BIND(STB_WEAK),
164 #undef SYM_BIND
165 };
166 const char *name = "unknown sym bind name";
167 if (bind < ARRAY_SIZE(bind_name)) {
168 name = bind_name[bind];
169 }
170 return name;
171 }
172
173 static const char *sym_visibility(unsigned visibility)
174 {
175 static const char *visibility_name[] = {
176 #define SYM_VISIBILITY(X) [X] = #X
177 SYM_VISIBILITY(STV_DEFAULT),
178 SYM_VISIBILITY(STV_INTERNAL),
179 SYM_VISIBILITY(STV_HIDDEN),
180 SYM_VISIBILITY(STV_PROTECTED),
181 #undef SYM_VISIBILITY
182 };
183 const char *name = "unknown sym visibility name";
184 if (visibility < ARRAY_SIZE(visibility_name)) {
185 name = visibility_name[visibility];
186 }
187 return name;
188 }
189
190 static const char *rel_type(unsigned type)
191 {
192 static const char *type_name[] = {
193 #define REL_TYPE(X) [X] = #X
194 #if ELF_BITS == 64
195 REL_TYPE(R_X86_64_NONE),
196 REL_TYPE(R_X86_64_64),
197 REL_TYPE(R_X86_64_PC32),
198 REL_TYPE(R_X86_64_GOT32),
199 REL_TYPE(R_X86_64_PLT32),
200 REL_TYPE(R_X86_64_COPY),
201 REL_TYPE(R_X86_64_GLOB_DAT),
202 REL_TYPE(R_X86_64_JUMP_SLOT),
203 REL_TYPE(R_X86_64_RELATIVE),
204 REL_TYPE(R_X86_64_GOTPCREL),
205 REL_TYPE(R_X86_64_32),
206 REL_TYPE(R_X86_64_32S),
207 REL_TYPE(R_X86_64_16),
208 REL_TYPE(R_X86_64_PC16),
209 REL_TYPE(R_X86_64_8),
210 REL_TYPE(R_X86_64_PC8),
211 #else
212 REL_TYPE(R_386_NONE),
213 REL_TYPE(R_386_32),
214 REL_TYPE(R_386_PC32),
215 REL_TYPE(R_386_GOT32),
216 REL_TYPE(R_386_PLT32),
217 REL_TYPE(R_386_COPY),
218 REL_TYPE(R_386_GLOB_DAT),
219 REL_TYPE(R_386_JMP_SLOT),
220 REL_TYPE(R_386_RELATIVE),
221 REL_TYPE(R_386_GOTOFF),
222 REL_TYPE(R_386_GOTPC),
223 REL_TYPE(R_386_8),
224 REL_TYPE(R_386_PC8),
225 REL_TYPE(R_386_16),
226 REL_TYPE(R_386_PC16),
227 #endif
228 #undef REL_TYPE
229 };
230 const char *name = "unknown type rel type name";
231 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
232 name = type_name[type];
233 }
234 return name;
235 }
236
237 static const char *sec_name(unsigned shndx)
238 {
239 const char *sec_strtab;
240 const char *name;
241 sec_strtab = secs[ehdr.e_shstrndx].strtab;
242 name = "<noname>";
243 if (shndx < ehdr.e_shnum) {
244 name = sec_strtab + secs[shndx].shdr.sh_name;
245 }
246 else if (shndx == SHN_ABS) {
247 name = "ABSOLUTE";
248 }
249 else if (shndx == SHN_COMMON) {
250 name = "COMMON";
251 }
252 return name;
253 }
254
255 static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
256 {
257 const char *name;
258 name = "<noname>";
259 if (sym->st_name) {
260 name = sym_strtab + sym->st_name;
261 }
262 else {
263 name = sec_name(sym->st_shndx);
264 }
265 return name;
266 }
267
268 static Elf_Sym *sym_lookup(const char *symname)
269 {
270 int i;
271 for (i = 0; i < ehdr.e_shnum; i++) {
272 struct section *sec = &secs[i];
273 long nsyms;
274 char *strtab;
275 Elf_Sym *symtab;
276 Elf_Sym *sym;
277
278 if (sec->shdr.sh_type != SHT_SYMTAB)
279 continue;
280
281 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
282 symtab = sec->symtab;
283 strtab = sec->link->strtab;
284
285 for (sym = symtab; --nsyms >= 0; sym++) {
286 if (!sym->st_name)
287 continue;
288 if (strcmp(symname, strtab + sym->st_name) == 0)
289 return sym;
290 }
291 }
292 return 0;
293 }
294
295 #if BYTE_ORDER == LITTLE_ENDIAN
296 #define le16_to_cpu(val) (val)
297 #define le32_to_cpu(val) (val)
298 #define le64_to_cpu(val) (val)
299 #endif
300 #if BYTE_ORDER == BIG_ENDIAN
301 #define le16_to_cpu(val) bswap_16(val)
302 #define le32_to_cpu(val) bswap_32(val)
303 #define le64_to_cpu(val) bswap_64(val)
304 #endif
305
306 static uint16_t elf16_to_cpu(uint16_t val)
307 {
308 return le16_to_cpu(val);
309 }
310
311 static uint32_t elf32_to_cpu(uint32_t val)
312 {
313 return le32_to_cpu(val);
314 }
315
316 #define elf_half_to_cpu(x) elf16_to_cpu(x)
317 #define elf_word_to_cpu(x) elf32_to_cpu(x)
318
319 #if ELF_BITS == 64
320 static uint64_t elf64_to_cpu(uint64_t val)
321 {
322 return le64_to_cpu(val);
323 }
324 #define elf_addr_to_cpu(x) elf64_to_cpu(x)
325 #define elf_off_to_cpu(x) elf64_to_cpu(x)
326 #define elf_xword_to_cpu(x) elf64_to_cpu(x)
327 #else
328 #define elf_addr_to_cpu(x) elf32_to_cpu(x)
329 #define elf_off_to_cpu(x) elf32_to_cpu(x)
330 #define elf_xword_to_cpu(x) elf32_to_cpu(x)
331 #endif
332
333 static void read_ehdr(FILE *fp)
334 {
335 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
336 die("Cannot read ELF header: %s\n",
337 strerror(errno));
338 }
339 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
340 die("No ELF magic\n");
341 }
342 if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
343 die("Not a %d bit executable\n", ELF_BITS);
344 }
345 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
346 die("Not a LSB ELF executable\n");
347 }
348 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
349 die("Unknown ELF version\n");
350 }
351 /* Convert the fields to native endian */
352 ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
353 ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
354 ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
355 ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
356 ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
357 ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
358 ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
359 ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
360 ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
361 ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
362 ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
363 ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
364 ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
365
366 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
367 die("Unsupported ELF header type\n");
368 }
369 if (ehdr.e_machine != ELF_MACHINE) {
370 die("Not for %s\n", ELF_MACHINE_NAME);
371 }
372 if (ehdr.e_version != EV_CURRENT) {
373 die("Unknown ELF version\n");
374 }
375 if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
376 die("Bad Elf header size\n");
377 }
378 if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
379 die("Bad program header entry\n");
380 }
381 if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
382 die("Bad section header entry\n");
383 }
384 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
385 die("String table index out of bounds\n");
386 }
387 }
388
389 static void read_shdrs(FILE *fp)
390 {
391 int i;
392 Elf_Shdr shdr;
393
394 secs = calloc(ehdr.e_shnum, sizeof(struct section));
395 if (!secs) {
396 die("Unable to allocate %d section headers\n",
397 ehdr.e_shnum);
398 }
399 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
400 die("Seek to %d failed: %s\n",
401 ehdr.e_shoff, strerror(errno));
402 }
403 for (i = 0; i < ehdr.e_shnum; i++) {
404 struct section *sec = &secs[i];
405 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
406 die("Cannot read ELF section headers %d/%d: %s\n",
407 i, ehdr.e_shnum, strerror(errno));
408 sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
409 sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
410 sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
411 sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
412 sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
413 sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
414 sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
415 sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
416 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
417 sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
418 if (sec->shdr.sh_link < ehdr.e_shnum)
419 sec->link = &secs[sec->shdr.sh_link];
420 }
421
422 }
423
424 static void read_strtabs(FILE *fp)
425 {
426 int i;
427 for (i = 0; i < ehdr.e_shnum; i++) {
428 struct section *sec = &secs[i];
429 if (sec->shdr.sh_type != SHT_STRTAB) {
430 continue;
431 }
432 sec->strtab = malloc(sec->shdr.sh_size);
433 if (!sec->strtab) {
434 die("malloc of %d bytes for strtab failed\n",
435 sec->shdr.sh_size);
436 }
437 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
438 die("Seek to %d failed: %s\n",
439 sec->shdr.sh_offset, strerror(errno));
440 }
441 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
442 != sec->shdr.sh_size) {
443 die("Cannot read symbol table: %s\n",
444 strerror(errno));
445 }
446 }
447 }
448
449 static void read_symtabs(FILE *fp)
450 {
451 int i,j;
452 for (i = 0; i < ehdr.e_shnum; i++) {
453 struct section *sec = &secs[i];
454 if (sec->shdr.sh_type != SHT_SYMTAB) {
455 continue;
456 }
457 sec->symtab = malloc(sec->shdr.sh_size);
458 if (!sec->symtab) {
459 die("malloc of %d bytes for symtab failed\n",
460 sec->shdr.sh_size);
461 }
462 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
463 die("Seek to %d failed: %s\n",
464 sec->shdr.sh_offset, strerror(errno));
465 }
466 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
467 != sec->shdr.sh_size) {
468 die("Cannot read symbol table: %s\n",
469 strerror(errno));
470 }
471 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
472 Elf_Sym *sym = &sec->symtab[j];
473 sym->st_name = elf_word_to_cpu(sym->st_name);
474 sym->st_value = elf_addr_to_cpu(sym->st_value);
475 sym->st_size = elf_xword_to_cpu(sym->st_size);
476 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
477 }
478 }
479 }
480
481
482 static void read_relocs(FILE *fp)
483 {
484 int i,j;
485 for (i = 0; i < ehdr.e_shnum; i++) {
486 struct section *sec = &secs[i];
487 if (sec->shdr.sh_type != SHT_REL_TYPE) {
488 continue;
489 }
490 sec->reltab = malloc(sec->shdr.sh_size);
491 if (!sec->reltab) {
492 die("malloc of %d bytes for relocs failed\n",
493 sec->shdr.sh_size);
494 }
495 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
496 die("Seek to %d failed: %s\n",
497 sec->shdr.sh_offset, strerror(errno));
498 }
499 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
500 != sec->shdr.sh_size) {
501 die("Cannot read symbol table: %s\n",
502 strerror(errno));
503 }
504 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
505 Elf_Rel *rel = &sec->reltab[j];
506 rel->r_offset = elf_addr_to_cpu(rel->r_offset);
507 rel->r_info = elf_xword_to_cpu(rel->r_info);
508 #if (SHT_REL_TYPE == SHT_RELA)
509 rel->r_addend = elf_xword_to_cpu(rel->r_addend);
510 #endif
511 }
512 }
513 }
514
515
516 static void print_absolute_symbols(void)
517 {
518 int i;
519 const char *format;
520
521 if (ELF_BITS == 64)
522 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
523 else
524 format = "%5d %08"PRIx32" %5"PRId32" %10s %10s %12s %s\n";
525
526 printf("Absolute symbols\n");
527 printf(" Num: Value Size Type Bind Visibility Name\n");
528 for (i = 0; i < ehdr.e_shnum; i++) {
529 struct section *sec = &secs[i];
530 char *sym_strtab;
531 int j;
532
533 if (sec->shdr.sh_type != SHT_SYMTAB) {
534 continue;
535 }
536 sym_strtab = sec->link->strtab;
537 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
538 Elf_Sym *sym;
539 const char *name;
540 sym = &sec->symtab[j];
541 name = sym_name(sym_strtab, sym);
542 if (sym->st_shndx != SHN_ABS) {
543 continue;
544 }
545 printf(format,
546 j, sym->st_value, sym->st_size,
547 sym_type(ELF_ST_TYPE(sym->st_info)),
548 sym_bind(ELF_ST_BIND(sym->st_info)),
549 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
550 name);
551 }
552 }
553 printf("\n");
554 }
555
556 static void print_absolute_relocs(void)
557 {
558 int i, printed = 0;
559 const char *format;
560
561 if (ELF_BITS == 64)
562 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64" %s\n";
563 else
564 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
565
566 for (i = 0; i < ehdr.e_shnum; i++) {
567 struct section *sec = &secs[i];
568 struct section *sec_applies, *sec_symtab;
569 char *sym_strtab;
570 Elf_Sym *sh_symtab;
571 int j;
572 if (sec->shdr.sh_type != SHT_REL_TYPE) {
573 continue;
574 }
575 sec_symtab = sec->link;
576 sec_applies = &secs[sec->shdr.sh_info];
577 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
578 continue;
579 }
580 sh_symtab = sec_symtab->symtab;
581 sym_strtab = sec_symtab->link->strtab;
582 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
583 Elf_Rel *rel;
584 Elf_Sym *sym;
585 const char *name;
586 rel = &sec->reltab[j];
587 sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
588 name = sym_name(sym_strtab, sym);
589 if (sym->st_shndx != SHN_ABS) {
590 continue;
591 }
592
593 /* Absolute symbols are not relocated if bzImage is
594 * loaded at a non-compiled address. Display a warning
595 * to user at compile time about the absolute
596 * relocations present.
597 *
598 * User need to audit the code to make sure
599 * some symbols which should have been section
600 * relative have not become absolute because of some
601 * linker optimization or wrong programming usage.
602 *
603 * Before warning check if this absolute symbol
604 * relocation is harmless.
605 */
606 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
607 continue;
608
609 if (!printed) {
610 printf("WARNING: Absolute relocations"
611 " present\n");
612 printf("Offset Info Type Sym.Value "
613 "Sym.Name\n");
614 printed = 1;
615 }
616
617 printf(format,
618 rel->r_offset,
619 rel->r_info,
620 rel_type(ELF_R_TYPE(rel->r_info)),
621 sym->st_value,
622 name);
623 }
624 }
625
626 if (printed)
627 printf("\n");
628 }
629
630 static void add_reloc(struct relocs *r, uint32_t offset)
631 {
632 if (r->count == r->size) {
633 unsigned long newsize = r->size + 50000;
634 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
635
636 if (!mem)
637 die("realloc of %ld entries for relocs failed\n",
638 newsize);
639 r->offset = mem;
640 r->size = newsize;
641 }
642 r->offset[r->count++] = offset;
643 }
644
645 static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
646 Elf_Sym *sym, const char *symname))
647 {
648 int i;
649 /* Walk through the relocations */
650 for (i = 0; i < ehdr.e_shnum; i++) {
651 char *sym_strtab;
652 Elf_Sym *sh_symtab;
653 struct section *sec_applies, *sec_symtab;
654 int j;
655 struct section *sec = &secs[i];
656
657 if (sec->shdr.sh_type != SHT_REL_TYPE) {
658 continue;
659 }
660 sec_symtab = sec->link;
661 sec_applies = &secs[sec->shdr.sh_info];
662 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
663 continue;
664 }
665 sh_symtab = sec_symtab->symtab;
666 sym_strtab = sec_symtab->link->strtab;
667 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
668 Elf_Rel *rel = &sec->reltab[j];
669 Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
670 const char *symname = sym_name(sym_strtab, sym);
671
672 process(sec, rel, sym, symname);
673 }
674 }
675 }
676
677 /*
678 * The .data..percpu section is a special case for x86_64 SMP kernels.
679 * It is used to initialize the actual per_cpu areas and to provide
680 * definitions for the per_cpu variables that correspond to their offsets
681 * within the percpu area. Since the values of all of the symbols need
682 * to be offsets from the start of the per_cpu area the virtual address
683 * (sh_addr) of .data..percpu is 0 in SMP kernels.
684 *
685 * This means that:
686 *
687 * Relocations that reference symbols in the per_cpu area do not
688 * need further relocation (since the value is an offset relative
689 * to the start of the per_cpu area that does not change).
690 *
691 * Relocations that apply to the per_cpu area need to have their
692 * offset adjusted by by the value of __per_cpu_load to make them
693 * point to the correct place in the loaded image (because the
694 * virtual address of .data..percpu is 0).
695 *
696 * For non SMP kernels .data..percpu is linked as part of the normal
697 * kernel data and does not require special treatment.
698 *
699 */
700 static int per_cpu_shndx = -1;
701 static Elf_Addr per_cpu_load_addr;
702
703 static void percpu_init(void)
704 {
705 int i;
706 for (i = 0; i < ehdr.e_shnum; i++) {
707 ElfW(Sym) *sym;
708 if (strcmp(sec_name(i), ".data..percpu"))
709 continue;
710
711 if (secs[i].shdr.sh_addr != 0) /* non SMP kernel */
712 return;
713
714 sym = sym_lookup("__per_cpu_load");
715 if (!sym)
716 die("can't find __per_cpu_load\n");
717
718 per_cpu_shndx = i;
719 per_cpu_load_addr = sym->st_value;
720 return;
721 }
722 }
723
724 #if ELF_BITS == 64
725
726 /*
727 * Check to see if a symbol lies in the .data..percpu section.
728 *
729 * The linker incorrectly associates some symbols with the
730 * .data..percpu section so we also need to check the symbol
731 * name to make sure that we classify the symbol correctly.
732 *
733 * The GNU linker incorrectly associates:
734 * __init_begin
735 * __per_cpu_load
736 *
737 * The "gold" linker incorrectly associates:
738 * init_per_cpu__irq_stack_union
739 * init_per_cpu__gdt_page
740 */
741 static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
742 {
743 return (sym->st_shndx == per_cpu_shndx) &&
744 strcmp(symname, "__init_begin") &&
745 strcmp(symname, "__per_cpu_load") &&
746 strncmp(symname, "init_per_cpu_", 13);
747 }
748
749
750 static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
751 const char *symname)
752 {
753 unsigned r_type = ELF64_R_TYPE(rel->r_info);
754 ElfW(Addr) offset = rel->r_offset;
755 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
756
757 if (sym->st_shndx == SHN_UNDEF)
758 return 0;
759
760 /*
761 * Adjust the offset if this reloc applies to the percpu section.
762 */
763 if (sec->shdr.sh_info == per_cpu_shndx)
764 offset += per_cpu_load_addr;
765
766 switch (r_type) {
767 case R_X86_64_NONE:
768 /* NONE can be ignored. */
769 break;
770
771 case R_X86_64_PC32:
772 case R_X86_64_PLT32:
773 /*
774 * PC relative relocations don't need to be adjusted unless
775 * referencing a percpu symbol.
776 *
777 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
778 */
779 if (is_percpu_sym(sym, symname))
780 add_reloc(&relocs32neg, offset);
781 break;
782
783 case R_X86_64_32:
784 case R_X86_64_32S:
785 case R_X86_64_64:
786 /*
787 * References to the percpu area don't need to be adjusted.
788 */
789 if (is_percpu_sym(sym, symname))
790 break;
791
792 if (shn_abs) {
793 /*
794 * Whitelisted absolute symbols do not require
795 * relocation.
796 */
797 if (is_reloc(S_ABS, symname))
798 break;
799
800 die("Invalid absolute %s relocation: %s\n",
801 rel_type(r_type), symname);
802 break;
803 }
804
805 /*
806 * Relocation offsets for 64 bit kernels are output
807 * as 32 bits and sign extended back to 64 bits when
808 * the relocations are processed.
809 * Make sure that the offset will fit.
810 */
811 if ((int32_t)offset != (int64_t)offset)
812 die("Relocation offset doesn't fit in 32 bits\n");
813
814 if (r_type == R_X86_64_64)
815 add_reloc(&relocs64, offset);
816 else
817 add_reloc(&relocs32, offset);
818 break;
819
820 default:
821 die("Unsupported relocation type: %s (%d)\n",
822 rel_type(r_type), r_type);
823 break;
824 }
825
826 return 0;
827 }
828
829 #else
830
831 static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
832 const char *symname)
833 {
834 unsigned r_type = ELF32_R_TYPE(rel->r_info);
835 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
836
837 switch (r_type) {
838 case R_386_NONE:
839 case R_386_PC32:
840 case R_386_PC16:
841 case R_386_PC8:
842 /*
843 * NONE can be ignored and PC relative relocations don't
844 * need to be adjusted.
845 */
846 break;
847
848 case R_386_32:
849 if (shn_abs) {
850 /*
851 * Whitelisted absolute symbols do not require
852 * relocation.
853 */
854 if (is_reloc(S_ABS, symname))
855 break;
856
857 die("Invalid absolute %s relocation: %s\n",
858 rel_type(r_type), symname);
859 break;
860 }
861
862 add_reloc(&relocs32, rel->r_offset);
863 break;
864
865 default:
866 die("Unsupported relocation type: %s (%d)\n",
867 rel_type(r_type), r_type);
868 break;
869 }
870
871 return 0;
872 }
873
874 static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
875 const char *symname)
876 {
877 unsigned r_type = ELF32_R_TYPE(rel->r_info);
878 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
879
880 switch (r_type) {
881 case R_386_NONE:
882 case R_386_PC32:
883 case R_386_PC16:
884 case R_386_PC8:
885 /*
886 * NONE can be ignored and PC relative relocations don't
887 * need to be adjusted.
888 */
889 break;
890
891 case R_386_16:
892 if (shn_abs) {
893 /*
894 * Whitelisted absolute symbols do not require
895 * relocation.
896 */
897 if (is_reloc(S_ABS, symname))
898 break;
899
900 if (is_reloc(S_SEG, symname)) {
901 add_reloc(&relocs16, rel->r_offset);
902 break;
903 }
904 } else {
905 if (!is_reloc(S_LIN, symname))
906 break;
907 }
908 die("Invalid %s %s relocation: %s\n",
909 shn_abs ? "absolute" : "relative",
910 rel_type(r_type), symname);
911 break;
912
913 case R_386_32:
914 if (shn_abs) {
915 /*
916 * Whitelisted absolute symbols do not require
917 * relocation.
918 */
919 if (is_reloc(S_ABS, symname))
920 break;
921
922 if (is_reloc(S_REL, symname)) {
923 add_reloc(&relocs32, rel->r_offset);
924 break;
925 }
926 } else {
927 if (is_reloc(S_LIN, symname))
928 add_reloc(&relocs32, rel->r_offset);
929 break;
930 }
931 die("Invalid %s %s relocation: %s\n",
932 shn_abs ? "absolute" : "relative",
933 rel_type(r_type), symname);
934 break;
935
936 default:
937 die("Unsupported relocation type: %s (%d)\n",
938 rel_type(r_type), r_type);
939 break;
940 }
941
942 return 0;
943 }
944
945 #endif
946
947 static int cmp_relocs(const void *va, const void *vb)
948 {
949 const uint32_t *a, *b;
950 a = va; b = vb;
951 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
952 }
953
954 static void sort_relocs(struct relocs *r)
955 {
956 qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
957 }
958
959 static int write32(uint32_t v, FILE *f)
960 {
961 unsigned char buf[4];
962
963 put_unaligned_le32(v, buf);
964 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
965 }
966
967 static int write32_as_text(uint32_t v, FILE *f)
968 {
969 return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
970 }
971
972 static void emit_relocs(int as_text, int use_real_mode)
973 {
974 int i;
975 int (*write_reloc)(uint32_t, FILE *) = write32;
976 int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
977 const char *symname);
978
979 #if ELF_BITS == 64
980 if (!use_real_mode)
981 do_reloc = do_reloc64;
982 else
983 die("--realmode not valid for a 64-bit ELF file");
984 #else
985 if (!use_real_mode)
986 do_reloc = do_reloc32;
987 else
988 do_reloc = do_reloc_real;
989 #endif
990
991 /* Collect up the relocations */
992 walk_relocs(do_reloc);
993
994 if (relocs16.count && !use_real_mode)
995 die("Segment relocations found but --realmode not specified\n");
996
997 /* Order the relocations for more efficient processing */
998 sort_relocs(&relocs32);
999 #if ELF_BITS == 64
1000 sort_relocs(&relocs32neg);
1001 sort_relocs(&relocs64);
1002 #else
1003 sort_relocs(&relocs16);
1004 #endif
1005
1006 /* Print the relocations */
1007 if (as_text) {
1008 /* Print the relocations in a form suitable that
1009 * gas will like.
1010 */
1011 printf(".section \".data.reloc\",\"a\"\n");
1012 printf(".balign 4\n");
1013 write_reloc = write32_as_text;
1014 }
1015
1016 if (use_real_mode) {
1017 write_reloc(relocs16.count, stdout);
1018 for (i = 0; i < relocs16.count; i++)
1019 write_reloc(relocs16.offset[i], stdout);
1020
1021 write_reloc(relocs32.count, stdout);
1022 for (i = 0; i < relocs32.count; i++)
1023 write_reloc(relocs32.offset[i], stdout);
1024 } else {
1025 #if ELF_BITS == 64
1026 /* Print a stop */
1027 write_reloc(0, stdout);
1028
1029 /* Now print each relocation */
1030 for (i = 0; i < relocs64.count; i++)
1031 write_reloc(relocs64.offset[i], stdout);
1032
1033 /* Print a stop */
1034 write_reloc(0, stdout);
1035
1036 /* Now print each inverse 32-bit relocation */
1037 for (i = 0; i < relocs32neg.count; i++)
1038 write_reloc(relocs32neg.offset[i], stdout);
1039 #endif
1040
1041 /* Print a stop */
1042 write_reloc(0, stdout);
1043
1044 /* Now print each relocation */
1045 for (i = 0; i < relocs32.count; i++)
1046 write_reloc(relocs32.offset[i], stdout);
1047 }
1048 }
1049
1050 /*
1051 * As an aid to debugging problems with different linkers
1052 * print summary information about the relocs.
1053 * Since different linkers tend to emit the sections in
1054 * different orders we use the section names in the output.
1055 */
1056 static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1057 const char *symname)
1058 {
1059 printf("%s\t%s\t%s\t%s\n",
1060 sec_name(sec->shdr.sh_info),
1061 rel_type(ELF_R_TYPE(rel->r_info)),
1062 symname,
1063 sec_name(sym->st_shndx));
1064 return 0;
1065 }
1066
1067 static void print_reloc_info(void)
1068 {
1069 printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1070 walk_relocs(do_reloc_info);
1071 }
1072
1073 #if ELF_BITS == 64
1074 # define process process_64
1075 #else
1076 # define process process_32
1077 #endif
1078
1079 void process(FILE *fp, int use_real_mode, int as_text,
1080 int show_absolute_syms, int show_absolute_relocs,
1081 int show_reloc_info)
1082 {
1083 regex_init(use_real_mode);
1084 read_ehdr(fp);
1085 read_shdrs(fp);
1086 read_strtabs(fp);
1087 read_symtabs(fp);
1088 read_relocs(fp);
1089 if (ELF_BITS == 64)
1090 percpu_init();
1091 if (show_absolute_syms) {
1092 print_absolute_symbols();
1093 return;
1094 }
1095 if (show_absolute_relocs) {
1096 print_absolute_relocs();
1097 return;
1098 }
1099 if (show_reloc_info) {
1100 print_reloc_info();
1101 return;
1102 }
1103 emit_relocs(as_text, use_real_mode);
1104 }
Linux with added FPC-III support