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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
13static Elf_Ehdr ehdr;
14
15struct relocs {
16 uint32_t *offset;
17 unsigned long count;
18 unsigned long size;
19};
20
21static struct relocs relocs16;
22static struct relocs relocs32;
23#if ELF_BITS == 64
24static struct relocs relocs32neg;
25static struct relocs relocs64;
26#endif
27
28struct section {
29 Elf_Shdr shdr;
30 struct section *link;
31 Elf_Sym *symtab;
32 Elf_Rel *reltab;
33 char *strtab;
34};
35static struct section *secs;
36
37static 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)$"
78};
79
80
81static const char * const sym_regex_realmode[S_NSYMTYPES] = {
82/*
83 * These symbols are known to be relative, even if the linker marks them
84 * as absolute (typically defined outside any section in the linker script.)
85 */
86 [S_REL] =
87 "^pa_",
88
89/*
90 * These are 16-bit segment symbols when compiling 16-bit code.
91 */
92 [S_SEG] =
93 "^real_mode_seg$",
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
103static const char * const *sym_regex;
104
105static regex_t sym_regex_c[S_NSYMTYPES];
106static 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
112static 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
137static 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
157static 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
173static 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
190static 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
237static 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
255static 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
268static 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
306static uint16_t elf16_to_cpu(uint16_t val)
307{
308 return le16_to_cpu(val);
309}
310
311static 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
320static 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
333static 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
389static 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
424static 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
449static 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
482static 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
516static 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
556static 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
630static 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
645static 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 */
700static int per_cpu_shndx = -1;
701static Elf_Addr per_cpu_load_addr;
702
703static 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 */
741static 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
750static 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 /*
773 * PC relative relocations don't need to be adjusted unless
774 * referencing a percpu symbol.
775 */
776 if (is_percpu_sym(sym, symname))
777 add_reloc(&relocs32neg, offset);
778 break;
779
780 case R_X86_64_32:
781 case R_X86_64_32S:
782 case R_X86_64_64:
783 /*
784 * References to the percpu area don't need to be adjusted.
785 */
786 if (is_percpu_sym(sym, symname))
787 break;
788
789 if (shn_abs) {
790 /*
791 * Whitelisted absolute symbols do not require
792 * relocation.
793 */
794 if (is_reloc(S_ABS, symname))
795 break;
796
797 die("Invalid absolute %s relocation: %s\n",
798 rel_type(r_type), symname);
799 break;
800 }
801
802 /*
803 * Relocation offsets for 64 bit kernels are output
804 * as 32 bits and sign extended back to 64 bits when
805 * the relocations are processed.
806 * Make sure that the offset will fit.
807 */
808 if ((int32_t)offset != (int64_t)offset)
809 die("Relocation offset doesn't fit in 32 bits\n");
810
811 if (r_type == R_X86_64_64)
812 add_reloc(&relocs64, offset);
813 else
814 add_reloc(&relocs32, offset);
815 break;
816
817 default:
818 die("Unsupported relocation type: %s (%d)\n",
819 rel_type(r_type), r_type);
820 break;
821 }
822
823 return 0;
824}
825
826#else
827
828static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
829 const char *symname)
830{
831 unsigned r_type = ELF32_R_TYPE(rel->r_info);
832 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
833
834 switch (r_type) {
835 case R_386_NONE:
836 case R_386_PC32:
837 case R_386_PC16:
838 case R_386_PC8:
839 /*
840 * NONE can be ignored and PC relative relocations don't
841 * need to be adjusted.
842 */
843 break;
844
845 case R_386_32:
846 if (shn_abs) {
847 /*
848 * Whitelisted absolute symbols do not require
849 * relocation.
850 */
851 if (is_reloc(S_ABS, symname))
852 break;
853
854 die("Invalid absolute %s relocation: %s\n",
855 rel_type(r_type), symname);
856 break;
857 }
858
859 add_reloc(&relocs32, rel->r_offset);
860 break;
861
862 default:
863 die("Unsupported relocation type: %s (%d)\n",
864 rel_type(r_type), r_type);
865 break;
866 }
867
868 return 0;
869}
870
871static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
872 const char *symname)
873{
874 unsigned r_type = ELF32_R_TYPE(rel->r_info);
875 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
876
877 switch (r_type) {
878 case R_386_NONE:
879 case R_386_PC32:
880 case R_386_PC16:
881 case R_386_PC8:
882 /*
883 * NONE can be ignored and PC relative relocations don't
884 * need to be adjusted.
885 */
886 break;
887
888 case R_386_16:
889 if (shn_abs) {
890 /*
891 * Whitelisted absolute symbols do not require
892 * relocation.
893 */
894 if (is_reloc(S_ABS, symname))
895 break;
896
897 if (is_reloc(S_SEG, symname)) {
898 add_reloc(&relocs16, rel->r_offset);
899 break;
900 }
901 } else {
902 if (!is_reloc(S_LIN, symname))
903 break;
904 }
905 die("Invalid %s %s relocation: %s\n",
906 shn_abs ? "absolute" : "relative",
907 rel_type(r_type), symname);
908 break;
909
910 case R_386_32:
911 if (shn_abs) {
912 /*
913 * Whitelisted absolute symbols do not require
914 * relocation.
915 */
916 if (is_reloc(S_ABS, symname))
917 break;
918
919 if (is_reloc(S_REL, symname)) {
920 add_reloc(&relocs32, rel->r_offset);
921 break;
922 }
923 } else {
924 if (is_reloc(S_LIN, symname))
925 add_reloc(&relocs32, rel->r_offset);
926 break;
927 }
928 die("Invalid %s %s relocation: %s\n",
929 shn_abs ? "absolute" : "relative",
930 rel_type(r_type), symname);
931 break;
932
933 default:
934 die("Unsupported relocation type: %s (%d)\n",
935 rel_type(r_type), r_type);
936 break;
937 }
938
939 return 0;
940}
941
942#endif
943
944static int cmp_relocs(const void *va, const void *vb)
945{
946 const uint32_t *a, *b;
947 a = va; b = vb;
948 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
949}
950
951static void sort_relocs(struct relocs *r)
952{
953 qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
954}
955
956static int write32(uint32_t v, FILE *f)
957{
958 unsigned char buf[4];
959
960 put_unaligned_le32(v, buf);
961 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
962}
963
964static int write32_as_text(uint32_t v, FILE *f)
965{
966 return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
967}
968
969static void emit_relocs(int as_text, int use_real_mode)
970{
971 int i;
972 int (*write_reloc)(uint32_t, FILE *) = write32;
973 int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
974 const char *symname);
975
976#if ELF_BITS == 64
977 if (!use_real_mode)
978 do_reloc = do_reloc64;
979 else
980 die("--realmode not valid for a 64-bit ELF file");
981#else
982 if (!use_real_mode)
983 do_reloc = do_reloc32;
984 else
985 do_reloc = do_reloc_real;
986#endif
987
988 /* Collect up the relocations */
989 walk_relocs(do_reloc);
990
991 if (relocs16.count && !use_real_mode)
992 die("Segment relocations found but --realmode not specified\n");
993
994 /* Order the relocations for more efficient processing */
995 sort_relocs(&relocs32);
996#if ELF_BITS == 64
997 sort_relocs(&relocs32neg);
998 sort_relocs(&relocs64);
999#else
1000 sort_relocs(&relocs16);
1001#endif
1002
1003 /* Print the relocations */
1004 if (as_text) {
1005 /* Print the relocations in a form suitable that
1006 * gas will like.
1007 */
1008 printf(".section \".data.reloc\",\"a\"\n");
1009 printf(".balign 4\n");
1010 write_reloc = write32_as_text;
1011 }
1012
1013 if (use_real_mode) {
1014 write_reloc(relocs16.count, stdout);
1015 for (i = 0; i < relocs16.count; i++)
1016 write_reloc(relocs16.offset[i], stdout);
1017
1018 write_reloc(relocs32.count, stdout);
1019 for (i = 0; i < relocs32.count; i++)
1020 write_reloc(relocs32.offset[i], stdout);
1021 } else {
1022#if ELF_BITS == 64
1023 /* Print a stop */
1024 write_reloc(0, stdout);
1025
1026 /* Now print each relocation */
1027 for (i = 0; i < relocs64.count; i++)
1028 write_reloc(relocs64.offset[i], stdout);
1029
1030 /* Print a stop */
1031 write_reloc(0, stdout);
1032
1033 /* Now print each inverse 32-bit relocation */
1034 for (i = 0; i < relocs32neg.count; i++)
1035 write_reloc(relocs32neg.offset[i], stdout);
1036#endif
1037
1038 /* Print a stop */
1039 write_reloc(0, stdout);
1040
1041 /* Now print each relocation */
1042 for (i = 0; i < relocs32.count; i++)
1043 write_reloc(relocs32.offset[i], stdout);
1044 }
1045}
1046
1047/*
1048 * As an aid to debugging problems with different linkers
1049 * print summary information about the relocs.
1050 * Since different linkers tend to emit the sections in
1051 * different orders we use the section names in the output.
1052 */
1053static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1054 const char *symname)
1055{
1056 printf("%s\t%s\t%s\t%s\n",
1057 sec_name(sec->shdr.sh_info),
1058 rel_type(ELF_R_TYPE(rel->r_info)),
1059 symname,
1060 sec_name(sym->st_shndx));
1061 return 0;
1062}
1063
1064static void print_reloc_info(void)
1065{
1066 printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1067 walk_relocs(do_reloc_info);
1068}
1069
1070#if ELF_BITS == 64
1071# define process process_64
1072#else
1073# define process process_32
1074#endif
1075
1076void process(FILE *fp, int use_real_mode, int as_text,
1077 int show_absolute_syms, int show_absolute_relocs,
1078 int show_reloc_info)
1079{
1080 regex_init(use_real_mode);
1081 read_ehdr(fp);
1082 read_shdrs(fp);
1083 read_strtabs(fp);
1084 read_symtabs(fp);
1085 read_relocs(fp);
1086 if (ELF_BITS == 64)
1087 percpu_init();
1088 if (show_absolute_syms) {
1089 print_absolute_symbols();
1090 return;
1091 }
1092 if (show_absolute_relocs) {
1093 print_absolute_relocs();
1094 return;
1095 }
1096 if (show_reloc_info) {
1097 print_reloc_info();
1098 return;
1099 }
1100 emit_relocs(as_text, use_real_mode);
1101}
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#include <tools/le_byteshift.h>
14
15static void die(char *fmt, ...);
16
17#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
18static Elf32_Ehdr ehdr;
19static unsigned long reloc_count, reloc_idx;
20static unsigned long *relocs;
21static unsigned long reloc16_count, reloc16_idx;
22static unsigned long *relocs16;
23
24struct section {
25 Elf32_Shdr shdr;
26 struct section *link;
27 Elf32_Sym *symtab;
28 Elf32_Rel *reltab;
29 char *strtab;
30};
31static struct section *secs;
32
33enum symtype {
34 S_ABS,
35 S_REL,
36 S_SEG,
37 S_LIN,
38 S_NSYMTYPES
39};
40
41static const char * const sym_regex_kernel[S_NSYMTYPES] = {
42/*
43 * Following symbols have been audited. There values are constant and do
44 * not change if bzImage is loaded at a different physical address than
45 * the address for which it has been compiled. Don't warn user about
46 * absolute relocations present w.r.t these symbols.
47 */
48 [S_ABS] =
49 "^(xen_irq_disable_direct_reloc$|"
50 "xen_save_fl_direct_reloc$|"
51 "VDSO|"
52 "__crc_)",
53
54/*
55 * These symbols are known to be relative, even if the linker marks them
56 * as absolute (typically defined outside any section in the linker script.)
57 */
58 [S_REL] =
59 "^(__init_(begin|end)|"
60 "__x86_cpu_dev_(start|end)|"
61 "(__parainstructions|__alt_instructions)(|_end)|"
62 "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
63 "__(start|end)_pci_.*|"
64 "__(start|end)_builtin_fw|"
65 "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
66 "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
67 "__(start|stop)___param|"
68 "__(start|stop)___modver|"
69 "__(start|stop)___bug_table|"
70 "__tracedata_(start|end)|"
71 "__(start|stop)_notes|"
72 "__end_rodata|"
73 "__initramfs_start|"
74 "(jiffies|jiffies_64)|"
75 "_end)$"
76};
77
78
79static const char * const sym_regex_realmode[S_NSYMTYPES] = {
80/*
81 * These symbols are known to be relative, even if the linker marks them
82 * as absolute (typically defined outside any section in the linker script.)
83 */
84 [S_REL] =
85 "^pa_",
86
87/*
88 * These are 16-bit segment symbols when compiling 16-bit code.
89 */
90 [S_SEG] =
91 "^real_mode_seg$",
92
93/*
94 * These are offsets belonging to segments, as opposed to linear addresses,
95 * when compiling 16-bit code.
96 */
97 [S_LIN] =
98 "^pa_",
99};
100
101static const char * const *sym_regex;
102
103static regex_t sym_regex_c[S_NSYMTYPES];
104static int is_reloc(enum symtype type, const char *sym_name)
105{
106 return sym_regex[type] &&
107 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
108}
109
110static void regex_init(int use_real_mode)
111{
112 char errbuf[128];
113 int err;
114 int i;
115
116 if (use_real_mode)
117 sym_regex = sym_regex_realmode;
118 else
119 sym_regex = sym_regex_kernel;
120
121 for (i = 0; i < S_NSYMTYPES; i++) {
122 if (!sym_regex[i])
123 continue;
124
125 err = regcomp(&sym_regex_c[i], sym_regex[i],
126 REG_EXTENDED|REG_NOSUB);
127
128 if (err) {
129 regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
130 die("%s", errbuf);
131 }
132 }
133}
134
135static void die(char *fmt, ...)
136{
137 va_list ap;
138 va_start(ap, fmt);
139 vfprintf(stderr, fmt, ap);
140 va_end(ap);
141 exit(1);
142}
143
144static const char *sym_type(unsigned type)
145{
146 static const char *type_name[] = {
147#define SYM_TYPE(X) [X] = #X
148 SYM_TYPE(STT_NOTYPE),
149 SYM_TYPE(STT_OBJECT),
150 SYM_TYPE(STT_FUNC),
151 SYM_TYPE(STT_SECTION),
152 SYM_TYPE(STT_FILE),
153 SYM_TYPE(STT_COMMON),
154 SYM_TYPE(STT_TLS),
155#undef SYM_TYPE
156 };
157 const char *name = "unknown sym type name";
158 if (type < ARRAY_SIZE(type_name)) {
159 name = type_name[type];
160 }
161 return name;
162}
163
164static const char *sym_bind(unsigned bind)
165{
166 static const char *bind_name[] = {
167#define SYM_BIND(X) [X] = #X
168 SYM_BIND(STB_LOCAL),
169 SYM_BIND(STB_GLOBAL),
170 SYM_BIND(STB_WEAK),
171#undef SYM_BIND
172 };
173 const char *name = "unknown sym bind name";
174 if (bind < ARRAY_SIZE(bind_name)) {
175 name = bind_name[bind];
176 }
177 return name;
178}
179
180static const char *sym_visibility(unsigned visibility)
181{
182 static const char *visibility_name[] = {
183#define SYM_VISIBILITY(X) [X] = #X
184 SYM_VISIBILITY(STV_DEFAULT),
185 SYM_VISIBILITY(STV_INTERNAL),
186 SYM_VISIBILITY(STV_HIDDEN),
187 SYM_VISIBILITY(STV_PROTECTED),
188#undef SYM_VISIBILITY
189 };
190 const char *name = "unknown sym visibility name";
191 if (visibility < ARRAY_SIZE(visibility_name)) {
192 name = visibility_name[visibility];
193 }
194 return name;
195}
196
197static const char *rel_type(unsigned type)
198{
199 static const char *type_name[] = {
200#define REL_TYPE(X) [X] = #X
201 REL_TYPE(R_386_NONE),
202 REL_TYPE(R_386_32),
203 REL_TYPE(R_386_PC32),
204 REL_TYPE(R_386_GOT32),
205 REL_TYPE(R_386_PLT32),
206 REL_TYPE(R_386_COPY),
207 REL_TYPE(R_386_GLOB_DAT),
208 REL_TYPE(R_386_JMP_SLOT),
209 REL_TYPE(R_386_RELATIVE),
210 REL_TYPE(R_386_GOTOFF),
211 REL_TYPE(R_386_GOTPC),
212 REL_TYPE(R_386_8),
213 REL_TYPE(R_386_PC8),
214 REL_TYPE(R_386_16),
215 REL_TYPE(R_386_PC16),
216#undef REL_TYPE
217 };
218 const char *name = "unknown type rel type name";
219 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
220 name = type_name[type];
221 }
222 return name;
223}
224
225static const char *sec_name(unsigned shndx)
226{
227 const char *sec_strtab;
228 const char *name;
229 sec_strtab = secs[ehdr.e_shstrndx].strtab;
230 name = "<noname>";
231 if (shndx < ehdr.e_shnum) {
232 name = sec_strtab + secs[shndx].shdr.sh_name;
233 }
234 else if (shndx == SHN_ABS) {
235 name = "ABSOLUTE";
236 }
237 else if (shndx == SHN_COMMON) {
238 name = "COMMON";
239 }
240 return name;
241}
242
243static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
244{
245 const char *name;
246 name = "<noname>";
247 if (sym->st_name) {
248 name = sym_strtab + sym->st_name;
249 }
250 else {
251 name = sec_name(sym->st_shndx);
252 }
253 return name;
254}
255
256
257
258#if BYTE_ORDER == LITTLE_ENDIAN
259#define le16_to_cpu(val) (val)
260#define le32_to_cpu(val) (val)
261#endif
262#if BYTE_ORDER == BIG_ENDIAN
263#define le16_to_cpu(val) bswap_16(val)
264#define le32_to_cpu(val) bswap_32(val)
265#endif
266
267static uint16_t elf16_to_cpu(uint16_t val)
268{
269 return le16_to_cpu(val);
270}
271
272static uint32_t elf32_to_cpu(uint32_t val)
273{
274 return le32_to_cpu(val);
275}
276
277static void read_ehdr(FILE *fp)
278{
279 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
280 die("Cannot read ELF header: %s\n",
281 strerror(errno));
282 }
283 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
284 die("No ELF magic\n");
285 }
286 if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
287 die("Not a 32 bit executable\n");
288 }
289 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
290 die("Not a LSB ELF executable\n");
291 }
292 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
293 die("Unknown ELF version\n");
294 }
295 /* Convert the fields to native endian */
296 ehdr.e_type = elf16_to_cpu(ehdr.e_type);
297 ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
298 ehdr.e_version = elf32_to_cpu(ehdr.e_version);
299 ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
300 ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
301 ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
302 ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
303 ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
304 ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
305 ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
306 ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
307 ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
308 ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
309
310 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
311 die("Unsupported ELF header type\n");
312 }
313 if (ehdr.e_machine != EM_386) {
314 die("Not for x86\n");
315 }
316 if (ehdr.e_version != EV_CURRENT) {
317 die("Unknown ELF version\n");
318 }
319 if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
320 die("Bad Elf header size\n");
321 }
322 if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
323 die("Bad program header entry\n");
324 }
325 if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
326 die("Bad section header entry\n");
327 }
328 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
329 die("String table index out of bounds\n");
330 }
331}
332
333static void read_shdrs(FILE *fp)
334{
335 int i;
336 Elf32_Shdr shdr;
337
338 secs = calloc(ehdr.e_shnum, sizeof(struct section));
339 if (!secs) {
340 die("Unable to allocate %d section headers\n",
341 ehdr.e_shnum);
342 }
343 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
344 die("Seek to %d failed: %s\n",
345 ehdr.e_shoff, strerror(errno));
346 }
347 for (i = 0; i < ehdr.e_shnum; i++) {
348 struct section *sec = &secs[i];
349 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
350 die("Cannot read ELF section headers %d/%d: %s\n",
351 i, ehdr.e_shnum, strerror(errno));
352 sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name);
353 sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type);
354 sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags);
355 sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr);
356 sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset);
357 sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size);
358 sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link);
359 sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info);
360 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
361 sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize);
362 if (sec->shdr.sh_link < ehdr.e_shnum)
363 sec->link = &secs[sec->shdr.sh_link];
364 }
365
366}
367
368static void read_strtabs(FILE *fp)
369{
370 int i;
371 for (i = 0; i < ehdr.e_shnum; i++) {
372 struct section *sec = &secs[i];
373 if (sec->shdr.sh_type != SHT_STRTAB) {
374 continue;
375 }
376 sec->strtab = malloc(sec->shdr.sh_size);
377 if (!sec->strtab) {
378 die("malloc of %d bytes for strtab failed\n",
379 sec->shdr.sh_size);
380 }
381 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
382 die("Seek to %d failed: %s\n",
383 sec->shdr.sh_offset, strerror(errno));
384 }
385 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
386 != sec->shdr.sh_size) {
387 die("Cannot read symbol table: %s\n",
388 strerror(errno));
389 }
390 }
391}
392
393static void read_symtabs(FILE *fp)
394{
395 int i,j;
396 for (i = 0; i < ehdr.e_shnum; i++) {
397 struct section *sec = &secs[i];
398 if (sec->shdr.sh_type != SHT_SYMTAB) {
399 continue;
400 }
401 sec->symtab = malloc(sec->shdr.sh_size);
402 if (!sec->symtab) {
403 die("malloc of %d bytes for symtab failed\n",
404 sec->shdr.sh_size);
405 }
406 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
407 die("Seek to %d failed: %s\n",
408 sec->shdr.sh_offset, strerror(errno));
409 }
410 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
411 != sec->shdr.sh_size) {
412 die("Cannot read symbol table: %s\n",
413 strerror(errno));
414 }
415 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
416 Elf32_Sym *sym = &sec->symtab[j];
417 sym->st_name = elf32_to_cpu(sym->st_name);
418 sym->st_value = elf32_to_cpu(sym->st_value);
419 sym->st_size = elf32_to_cpu(sym->st_size);
420 sym->st_shndx = elf16_to_cpu(sym->st_shndx);
421 }
422 }
423}
424
425
426static void read_relocs(FILE *fp)
427{
428 int i,j;
429 for (i = 0; i < ehdr.e_shnum; i++) {
430 struct section *sec = &secs[i];
431 if (sec->shdr.sh_type != SHT_REL) {
432 continue;
433 }
434 sec->reltab = malloc(sec->shdr.sh_size);
435 if (!sec->reltab) {
436 die("malloc of %d bytes for relocs failed\n",
437 sec->shdr.sh_size);
438 }
439 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
440 die("Seek to %d failed: %s\n",
441 sec->shdr.sh_offset, strerror(errno));
442 }
443 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
444 != sec->shdr.sh_size) {
445 die("Cannot read symbol table: %s\n",
446 strerror(errno));
447 }
448 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
449 Elf32_Rel *rel = &sec->reltab[j];
450 rel->r_offset = elf32_to_cpu(rel->r_offset);
451 rel->r_info = elf32_to_cpu(rel->r_info);
452 }
453 }
454}
455
456
457static void print_absolute_symbols(void)
458{
459 int i;
460 printf("Absolute symbols\n");
461 printf(" Num: Value Size Type Bind Visibility Name\n");
462 for (i = 0; i < ehdr.e_shnum; i++) {
463 struct section *sec = &secs[i];
464 char *sym_strtab;
465 int j;
466
467 if (sec->shdr.sh_type != SHT_SYMTAB) {
468 continue;
469 }
470 sym_strtab = sec->link->strtab;
471 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
472 Elf32_Sym *sym;
473 const char *name;
474 sym = &sec->symtab[j];
475 name = sym_name(sym_strtab, sym);
476 if (sym->st_shndx != SHN_ABS) {
477 continue;
478 }
479 printf("%5d %08x %5d %10s %10s %12s %s\n",
480 j, sym->st_value, sym->st_size,
481 sym_type(ELF32_ST_TYPE(sym->st_info)),
482 sym_bind(ELF32_ST_BIND(sym->st_info)),
483 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
484 name);
485 }
486 }
487 printf("\n");
488}
489
490static void print_absolute_relocs(void)
491{
492 int i, printed = 0;
493
494 for (i = 0; i < ehdr.e_shnum; i++) {
495 struct section *sec = &secs[i];
496 struct section *sec_applies, *sec_symtab;
497 char *sym_strtab;
498 Elf32_Sym *sh_symtab;
499 int j;
500 if (sec->shdr.sh_type != SHT_REL) {
501 continue;
502 }
503 sec_symtab = sec->link;
504 sec_applies = &secs[sec->shdr.sh_info];
505 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
506 continue;
507 }
508 sh_symtab = sec_symtab->symtab;
509 sym_strtab = sec_symtab->link->strtab;
510 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
511 Elf32_Rel *rel;
512 Elf32_Sym *sym;
513 const char *name;
514 rel = &sec->reltab[j];
515 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
516 name = sym_name(sym_strtab, sym);
517 if (sym->st_shndx != SHN_ABS) {
518 continue;
519 }
520
521 /* Absolute symbols are not relocated if bzImage is
522 * loaded at a non-compiled address. Display a warning
523 * to user at compile time about the absolute
524 * relocations present.
525 *
526 * User need to audit the code to make sure
527 * some symbols which should have been section
528 * relative have not become absolute because of some
529 * linker optimization or wrong programming usage.
530 *
531 * Before warning check if this absolute symbol
532 * relocation is harmless.
533 */
534 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
535 continue;
536
537 if (!printed) {
538 printf("WARNING: Absolute relocations"
539 " present\n");
540 printf("Offset Info Type Sym.Value "
541 "Sym.Name\n");
542 printed = 1;
543 }
544
545 printf("%08x %08x %10s %08x %s\n",
546 rel->r_offset,
547 rel->r_info,
548 rel_type(ELF32_R_TYPE(rel->r_info)),
549 sym->st_value,
550 name);
551 }
552 }
553
554 if (printed)
555 printf("\n");
556}
557
558static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
559 int use_real_mode)
560{
561 int i;
562 /* Walk through the relocations */
563 for (i = 0; i < ehdr.e_shnum; i++) {
564 char *sym_strtab;
565 Elf32_Sym *sh_symtab;
566 struct section *sec_applies, *sec_symtab;
567 int j;
568 struct section *sec = &secs[i];
569
570 if (sec->shdr.sh_type != SHT_REL) {
571 continue;
572 }
573 sec_symtab = sec->link;
574 sec_applies = &secs[sec->shdr.sh_info];
575 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
576 continue;
577 }
578 sh_symtab = sec_symtab->symtab;
579 sym_strtab = sec_symtab->link->strtab;
580 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
581 Elf32_Rel *rel;
582 Elf32_Sym *sym;
583 unsigned r_type;
584 const char *symname;
585 int shn_abs;
586
587 rel = &sec->reltab[j];
588 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
589 r_type = ELF32_R_TYPE(rel->r_info);
590
591 shn_abs = sym->st_shndx == SHN_ABS;
592
593 switch (r_type) {
594 case R_386_NONE:
595 case R_386_PC32:
596 case R_386_PC16:
597 case R_386_PC8:
598 /*
599 * NONE can be ignored and and PC relative
600 * relocations don't need to be adjusted.
601 */
602 break;
603
604 case R_386_16:
605 symname = sym_name(sym_strtab, sym);
606 if (!use_real_mode)
607 goto bad;
608 if (shn_abs) {
609 if (is_reloc(S_ABS, symname))
610 break;
611 else if (!is_reloc(S_SEG, symname))
612 goto bad;
613 } else {
614 if (is_reloc(S_LIN, symname))
615 goto bad;
616 else
617 break;
618 }
619 visit(rel, sym);
620 break;
621
622 case R_386_32:
623 symname = sym_name(sym_strtab, sym);
624 if (shn_abs) {
625 if (is_reloc(S_ABS, symname))
626 break;
627 else if (!is_reloc(S_REL, symname))
628 goto bad;
629 } else {
630 if (use_real_mode &&
631 !is_reloc(S_LIN, symname))
632 break;
633 }
634 visit(rel, sym);
635 break;
636 default:
637 die("Unsupported relocation type: %s (%d)\n",
638 rel_type(r_type), r_type);
639 break;
640 bad:
641 symname = sym_name(sym_strtab, sym);
642 die("Invalid %s %s relocation: %s\n",
643 shn_abs ? "absolute" : "relative",
644 rel_type(r_type), symname);
645 }
646 }
647 }
648}
649
650static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
651{
652 if (ELF32_R_TYPE(rel->r_info) == R_386_16)
653 reloc16_count++;
654 else
655 reloc_count++;
656}
657
658static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
659{
660 /* Remember the address that needs to be adjusted. */
661 if (ELF32_R_TYPE(rel->r_info) == R_386_16)
662 relocs16[reloc16_idx++] = rel->r_offset;
663 else
664 relocs[reloc_idx++] = rel->r_offset;
665}
666
667static int cmp_relocs(const void *va, const void *vb)
668{
669 const unsigned long *a, *b;
670 a = va; b = vb;
671 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
672}
673
674static int write32(unsigned int v, FILE *f)
675{
676 unsigned char buf[4];
677
678 put_unaligned_le32(v, buf);
679 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
680}
681
682static void emit_relocs(int as_text, int use_real_mode)
683{
684 int i;
685 /* Count how many relocations I have and allocate space for them. */
686 reloc_count = 0;
687 walk_relocs(count_reloc, use_real_mode);
688 relocs = malloc(reloc_count * sizeof(relocs[0]));
689 if (!relocs) {
690 die("malloc of %d entries for relocs failed\n",
691 reloc_count);
692 }
693
694 relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
695 if (!relocs16) {
696 die("malloc of %d entries for relocs16 failed\n",
697 reloc16_count);
698 }
699 /* Collect up the relocations */
700 reloc_idx = 0;
701 walk_relocs(collect_reloc, use_real_mode);
702
703 if (reloc16_count && !use_real_mode)
704 die("Segment relocations found but --realmode not specified\n");
705
706 /* Order the relocations for more efficient processing */
707 qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
708 qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
709
710 /* Print the relocations */
711 if (as_text) {
712 /* Print the relocations in a form suitable that
713 * gas will like.
714 */
715 printf(".section \".data.reloc\",\"a\"\n");
716 printf(".balign 4\n");
717 if (use_real_mode) {
718 printf("\t.long %lu\n", reloc16_count);
719 for (i = 0; i < reloc16_count; i++)
720 printf("\t.long 0x%08lx\n", relocs16[i]);
721 printf("\t.long %lu\n", reloc_count);
722 for (i = 0; i < reloc_count; i++) {
723 printf("\t.long 0x%08lx\n", relocs[i]);
724 }
725 } else {
726 /* Print a stop */
727 printf("\t.long 0x%08lx\n", (unsigned long)0);
728 for (i = 0; i < reloc_count; i++) {
729 printf("\t.long 0x%08lx\n", relocs[i]);
730 }
731 }
732
733 printf("\n");
734 }
735 else {
736 if (use_real_mode) {
737 write32(reloc16_count, stdout);
738 for (i = 0; i < reloc16_count; i++)
739 write32(relocs16[i], stdout);
740 write32(reloc_count, stdout);
741
742 /* Now print each relocation */
743 for (i = 0; i < reloc_count; i++)
744 write32(relocs[i], stdout);
745 } else {
746 /* Print a stop */
747 write32(0, stdout);
748
749 /* Now print each relocation */
750 for (i = 0; i < reloc_count; i++) {
751 write32(relocs[i], stdout);
752 }
753 }
754 }
755}
756
757static void usage(void)
758{
759 die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
760}
761
762int main(int argc, char **argv)
763{
764 int show_absolute_syms, show_absolute_relocs;
765 int as_text, use_real_mode;
766 const char *fname;
767 FILE *fp;
768 int i;
769
770 show_absolute_syms = 0;
771 show_absolute_relocs = 0;
772 as_text = 0;
773 use_real_mode = 0;
774 fname = NULL;
775 for (i = 1; i < argc; i++) {
776 char *arg = argv[i];
777 if (*arg == '-') {
778 if (strcmp(arg, "--abs-syms") == 0) {
779 show_absolute_syms = 1;
780 continue;
781 }
782 if (strcmp(arg, "--abs-relocs") == 0) {
783 show_absolute_relocs = 1;
784 continue;
785 }
786 if (strcmp(arg, "--text") == 0) {
787 as_text = 1;
788 continue;
789 }
790 if (strcmp(arg, "--realmode") == 0) {
791 use_real_mode = 1;
792 continue;
793 }
794 }
795 else if (!fname) {
796 fname = arg;
797 continue;
798 }
799 usage();
800 }
801 if (!fname) {
802 usage();
803 }
804 regex_init(use_real_mode);
805 fp = fopen(fname, "r");
806 if (!fp) {
807 die("Cannot open %s: %s\n",
808 fname, strerror(errno));
809 }
810 read_ehdr(fp);
811 read_shdrs(fp);
812 read_strtabs(fp);
813 read_symtabs(fp);
814 read_relocs(fp);
815 if (show_absolute_syms) {
816 print_absolute_symbols();
817 return 0;
818 }
819 if (show_absolute_relocs) {
820 print_absolute_relocs();
821 return 0;
822 }
823 emit_relocs(as_text, use_real_mode);
824 return 0;
825}