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1// SPDX-License-Identifier: GPL-2.0
2/* This is included from relocs_32/64.c */
3
4#define ElfW(type) _ElfW(ELF_BITS, type)
5#define _ElfW(bits, type) __ElfW(bits, type)
6#define __ElfW(bits, type) Elf##bits##_##type
7
8#define Elf_Addr ElfW(Addr)
9#define Elf_Ehdr ElfW(Ehdr)
10#define Elf_Phdr ElfW(Phdr)
11#define Elf_Shdr ElfW(Shdr)
12#define Elf_Sym ElfW(Sym)
13
14static Elf_Ehdr ehdr;
15static unsigned long shnum;
16static unsigned int shstrndx;
17
18struct relocs {
19 uint32_t *offset;
20 unsigned long count;
21 unsigned long size;
22};
23
24static struct relocs relocs16;
25static struct relocs relocs32;
26#if ELF_BITS == 64
27static struct relocs relocs32neg;
28static struct relocs relocs64;
29#endif
30
31struct section {
32 Elf_Shdr shdr;
33 struct section *link;
34 Elf_Sym *symtab;
35 Elf_Rel *reltab;
36 char *strtab;
37};
38static struct section *secs;
39
40static const char * const sym_regex_kernel[S_NSYMTYPES] = {
41/*
42 * Following symbols have been audited. There values are constant and do
43 * not change if bzImage is loaded at a different physical address than
44 * the address for which it has been compiled. Don't warn user about
45 * absolute relocations present w.r.t these symbols.
46 */
47 [S_ABS] =
48 "^(xen_irq_disable_direct_reloc$|"
49 "xen_save_fl_direct_reloc$|"
50 "VDSO|"
51 "__crc_)",
52
53/*
54 * These symbols are known to be relative, even if the linker marks them
55 * as absolute (typically defined outside any section in the linker script.)
56 */
57 [S_REL] =
58 "^(__init_(begin|end)|"
59 "__x86_cpu_dev_(start|end)|"
60 "(__parainstructions|__alt_instructions)(|_end)|"
61 "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
62 "__(start|end)_pci_.*|"
63 "__(start|end)_builtin_fw|"
64 "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
65 "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
66 "__(start|stop)___param|"
67 "__(start|stop)___modver|"
68 "__(start|stop)___bug_table|"
69 "__tracedata_(start|end)|"
70 "__(start|stop)_notes|"
71 "__end_rodata|"
72 "__end_rodata_aligned|"
73 "__initramfs_start|"
74 "(jiffies|jiffies_64)|"
75#if ELF_BITS == 64
76 "__per_cpu_load|"
77 "init_per_cpu__.*|"
78 "__end_rodata_hpage_align|"
79#endif
80 "__vvar_page|"
81 "_end)$"
82};
83
84
85static const char * const sym_regex_realmode[S_NSYMTYPES] = {
86/*
87 * These symbols are known to be relative, even if the linker marks them
88 * as absolute (typically defined outside any section in the linker script.)
89 */
90 [S_REL] =
91 "^pa_",
92
93/*
94 * These are 16-bit segment symbols when compiling 16-bit code.
95 */
96 [S_SEG] =
97 "^real_mode_seg$",
98
99/*
100 * These are offsets belonging to segments, as opposed to linear addresses,
101 * when compiling 16-bit code.
102 */
103 [S_LIN] =
104 "^pa_",
105};
106
107static const char * const *sym_regex;
108
109static regex_t sym_regex_c[S_NSYMTYPES];
110static int is_reloc(enum symtype type, const char *sym_name)
111{
112 return sym_regex[type] &&
113 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
114}
115
116static void regex_init(int use_real_mode)
117{
118 char errbuf[128];
119 int err;
120 int i;
121
122 if (use_real_mode)
123 sym_regex = sym_regex_realmode;
124 else
125 sym_regex = sym_regex_kernel;
126
127 for (i = 0; i < S_NSYMTYPES; i++) {
128 if (!sym_regex[i])
129 continue;
130
131 err = regcomp(&sym_regex_c[i], sym_regex[i],
132 REG_EXTENDED|REG_NOSUB);
133
134 if (err) {
135 regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf));
136 die("%s", errbuf);
137 }
138 }
139}
140
141static const char *sym_type(unsigned type)
142{
143 static const char *type_name[] = {
144#define SYM_TYPE(X) [X] = #X
145 SYM_TYPE(STT_NOTYPE),
146 SYM_TYPE(STT_OBJECT),
147 SYM_TYPE(STT_FUNC),
148 SYM_TYPE(STT_SECTION),
149 SYM_TYPE(STT_FILE),
150 SYM_TYPE(STT_COMMON),
151 SYM_TYPE(STT_TLS),
152#undef SYM_TYPE
153 };
154 const char *name = "unknown sym type name";
155 if (type < ARRAY_SIZE(type_name)) {
156 name = type_name[type];
157 }
158 return name;
159}
160
161static const char *sym_bind(unsigned bind)
162{
163 static const char *bind_name[] = {
164#define SYM_BIND(X) [X] = #X
165 SYM_BIND(STB_LOCAL),
166 SYM_BIND(STB_GLOBAL),
167 SYM_BIND(STB_WEAK),
168#undef SYM_BIND
169 };
170 const char *name = "unknown sym bind name";
171 if (bind < ARRAY_SIZE(bind_name)) {
172 name = bind_name[bind];
173 }
174 return name;
175}
176
177static const char *sym_visibility(unsigned visibility)
178{
179 static const char *visibility_name[] = {
180#define SYM_VISIBILITY(X) [X] = #X
181 SYM_VISIBILITY(STV_DEFAULT),
182 SYM_VISIBILITY(STV_INTERNAL),
183 SYM_VISIBILITY(STV_HIDDEN),
184 SYM_VISIBILITY(STV_PROTECTED),
185#undef SYM_VISIBILITY
186 };
187 const char *name = "unknown sym visibility name";
188 if (visibility < ARRAY_SIZE(visibility_name)) {
189 name = visibility_name[visibility];
190 }
191 return name;
192}
193
194static const char *rel_type(unsigned type)
195{
196 static const char *type_name[] = {
197#define REL_TYPE(X) [X] = #X
198#if ELF_BITS == 64
199 REL_TYPE(R_X86_64_NONE),
200 REL_TYPE(R_X86_64_64),
201 REL_TYPE(R_X86_64_PC64),
202 REL_TYPE(R_X86_64_PC32),
203 REL_TYPE(R_X86_64_GOT32),
204 REL_TYPE(R_X86_64_PLT32),
205 REL_TYPE(R_X86_64_COPY),
206 REL_TYPE(R_X86_64_GLOB_DAT),
207 REL_TYPE(R_X86_64_JUMP_SLOT),
208 REL_TYPE(R_X86_64_RELATIVE),
209 REL_TYPE(R_X86_64_GOTPCREL),
210 REL_TYPE(R_X86_64_32),
211 REL_TYPE(R_X86_64_32S),
212 REL_TYPE(R_X86_64_16),
213 REL_TYPE(R_X86_64_PC16),
214 REL_TYPE(R_X86_64_8),
215 REL_TYPE(R_X86_64_PC8),
216#else
217 REL_TYPE(R_386_NONE),
218 REL_TYPE(R_386_32),
219 REL_TYPE(R_386_PC32),
220 REL_TYPE(R_386_GOT32),
221 REL_TYPE(R_386_PLT32),
222 REL_TYPE(R_386_COPY),
223 REL_TYPE(R_386_GLOB_DAT),
224 REL_TYPE(R_386_JMP_SLOT),
225 REL_TYPE(R_386_RELATIVE),
226 REL_TYPE(R_386_GOTOFF),
227 REL_TYPE(R_386_GOTPC),
228 REL_TYPE(R_386_8),
229 REL_TYPE(R_386_PC8),
230 REL_TYPE(R_386_16),
231 REL_TYPE(R_386_PC16),
232#endif
233#undef REL_TYPE
234 };
235 const char *name = "unknown type rel type name";
236 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
237 name = type_name[type];
238 }
239 return name;
240}
241
242static const char *sec_name(unsigned shndx)
243{
244 const char *sec_strtab;
245 const char *name;
246 sec_strtab = secs[shstrndx].strtab;
247 name = "<noname>";
248 if (shndx < shnum) {
249 name = sec_strtab + secs[shndx].shdr.sh_name;
250 }
251 else if (shndx == SHN_ABS) {
252 name = "ABSOLUTE";
253 }
254 else if (shndx == SHN_COMMON) {
255 name = "COMMON";
256 }
257 return name;
258}
259
260static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
261{
262 const char *name;
263 name = "<noname>";
264 if (sym->st_name) {
265 name = sym_strtab + sym->st_name;
266 }
267 else {
268 name = sec_name(sym->st_shndx);
269 }
270 return name;
271}
272
273static Elf_Sym *sym_lookup(const char *symname)
274{
275 int i;
276 for (i = 0; i < shnum; i++) {
277 struct section *sec = &secs[i];
278 long nsyms;
279 char *strtab;
280 Elf_Sym *symtab;
281 Elf_Sym *sym;
282
283 if (sec->shdr.sh_type != SHT_SYMTAB)
284 continue;
285
286 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
287 symtab = sec->symtab;
288 strtab = sec->link->strtab;
289
290 for (sym = symtab; --nsyms >= 0; sym++) {
291 if (!sym->st_name)
292 continue;
293 if (strcmp(symname, strtab + sym->st_name) == 0)
294 return sym;
295 }
296 }
297 return 0;
298}
299
300#if BYTE_ORDER == LITTLE_ENDIAN
301#define le16_to_cpu(val) (val)
302#define le32_to_cpu(val) (val)
303#define le64_to_cpu(val) (val)
304#endif
305#if BYTE_ORDER == BIG_ENDIAN
306#define le16_to_cpu(val) bswap_16(val)
307#define le32_to_cpu(val) bswap_32(val)
308#define le64_to_cpu(val) bswap_64(val)
309#endif
310
311static uint16_t elf16_to_cpu(uint16_t val)
312{
313 return le16_to_cpu(val);
314}
315
316static uint32_t elf32_to_cpu(uint32_t val)
317{
318 return le32_to_cpu(val);
319}
320
321#define elf_half_to_cpu(x) elf16_to_cpu(x)
322#define elf_word_to_cpu(x) elf32_to_cpu(x)
323
324#if ELF_BITS == 64
325static uint64_t elf64_to_cpu(uint64_t val)
326{
327 return le64_to_cpu(val);
328}
329#define elf_addr_to_cpu(x) elf64_to_cpu(x)
330#define elf_off_to_cpu(x) elf64_to_cpu(x)
331#define elf_xword_to_cpu(x) elf64_to_cpu(x)
332#else
333#define elf_addr_to_cpu(x) elf32_to_cpu(x)
334#define elf_off_to_cpu(x) elf32_to_cpu(x)
335#define elf_xword_to_cpu(x) elf32_to_cpu(x)
336#endif
337
338static void read_ehdr(FILE *fp)
339{
340 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
341 die("Cannot read ELF header: %s\n",
342 strerror(errno));
343 }
344 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
345 die("No ELF magic\n");
346 }
347 if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
348 die("Not a %d bit executable\n", ELF_BITS);
349 }
350 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
351 die("Not a LSB ELF executable\n");
352 }
353 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
354 die("Unknown ELF version\n");
355 }
356 /* Convert the fields to native endian */
357 ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
358 ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
359 ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
360 ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
361 ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
362 ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
363 ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
364 ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
365 ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
366 ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
367 ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
368 ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
369 ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
370
371 shnum = ehdr.e_shnum;
372 shstrndx = ehdr.e_shstrndx;
373
374 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
375 die("Unsupported ELF header type\n");
376 if (ehdr.e_machine != ELF_MACHINE)
377 die("Not for %s\n", ELF_MACHINE_NAME);
378 if (ehdr.e_version != EV_CURRENT)
379 die("Unknown ELF version\n");
380 if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
381 die("Bad Elf header size\n");
382 if (ehdr.e_phentsize != sizeof(Elf_Phdr))
383 die("Bad program header entry\n");
384 if (ehdr.e_shentsize != sizeof(Elf_Shdr))
385 die("Bad section header entry\n");
386
387
388 if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
389 Elf_Shdr shdr;
390
391 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
392 die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));
393
394 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
395 die("Cannot read initial ELF section header: %s\n", strerror(errno));
396
397 if (shnum == SHN_UNDEF)
398 shnum = elf_xword_to_cpu(shdr.sh_size);
399
400 if (shstrndx == SHN_XINDEX)
401 shstrndx = elf_word_to_cpu(shdr.sh_link);
402 }
403
404 if (shstrndx >= shnum)
405 die("String table index out of bounds\n");
406}
407
408static void read_shdrs(FILE *fp)
409{
410 int i;
411 Elf_Shdr shdr;
412
413 secs = calloc(shnum, sizeof(struct section));
414 if (!secs) {
415 die("Unable to allocate %d section headers\n",
416 shnum);
417 }
418 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
419 die("Seek to %d failed: %s\n",
420 ehdr.e_shoff, strerror(errno));
421 }
422 for (i = 0; i < shnum; i++) {
423 struct section *sec = &secs[i];
424 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
425 die("Cannot read ELF section headers %d/%d: %s\n",
426 i, shnum, strerror(errno));
427 sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
428 sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
429 sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
430 sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
431 sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
432 sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
433 sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
434 sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
435 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
436 sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
437 if (sec->shdr.sh_link < shnum)
438 sec->link = &secs[sec->shdr.sh_link];
439 }
440
441}
442
443static void read_strtabs(FILE *fp)
444{
445 int i;
446 for (i = 0; i < shnum; i++) {
447 struct section *sec = &secs[i];
448 if (sec->shdr.sh_type != SHT_STRTAB) {
449 continue;
450 }
451 sec->strtab = malloc(sec->shdr.sh_size);
452 if (!sec->strtab) {
453 die("malloc of %d bytes for strtab failed\n",
454 sec->shdr.sh_size);
455 }
456 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
457 die("Seek to %d failed: %s\n",
458 sec->shdr.sh_offset, strerror(errno));
459 }
460 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
461 != sec->shdr.sh_size) {
462 die("Cannot read symbol table: %s\n",
463 strerror(errno));
464 }
465 }
466}
467
468static void read_symtabs(FILE *fp)
469{
470 int i,j;
471 for (i = 0; i < shnum; i++) {
472 struct section *sec = &secs[i];
473 if (sec->shdr.sh_type != SHT_SYMTAB) {
474 continue;
475 }
476 sec->symtab = malloc(sec->shdr.sh_size);
477 if (!sec->symtab) {
478 die("malloc of %d bytes for symtab failed\n",
479 sec->shdr.sh_size);
480 }
481 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
482 die("Seek to %d failed: %s\n",
483 sec->shdr.sh_offset, strerror(errno));
484 }
485 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
486 != sec->shdr.sh_size) {
487 die("Cannot read symbol table: %s\n",
488 strerror(errno));
489 }
490 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
491 Elf_Sym *sym = &sec->symtab[j];
492 sym->st_name = elf_word_to_cpu(sym->st_name);
493 sym->st_value = elf_addr_to_cpu(sym->st_value);
494 sym->st_size = elf_xword_to_cpu(sym->st_size);
495 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
496 }
497 }
498}
499
500
501static void read_relocs(FILE *fp)
502{
503 int i,j;
504 for (i = 0; i < shnum; i++) {
505 struct section *sec = &secs[i];
506 if (sec->shdr.sh_type != SHT_REL_TYPE) {
507 continue;
508 }
509 sec->reltab = malloc(sec->shdr.sh_size);
510 if (!sec->reltab) {
511 die("malloc of %d bytes for relocs failed\n",
512 sec->shdr.sh_size);
513 }
514 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
515 die("Seek to %d failed: %s\n",
516 sec->shdr.sh_offset, strerror(errno));
517 }
518 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
519 != sec->shdr.sh_size) {
520 die("Cannot read symbol table: %s\n",
521 strerror(errno));
522 }
523 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
524 Elf_Rel *rel = &sec->reltab[j];
525 rel->r_offset = elf_addr_to_cpu(rel->r_offset);
526 rel->r_info = elf_xword_to_cpu(rel->r_info);
527#if (SHT_REL_TYPE == SHT_RELA)
528 rel->r_addend = elf_xword_to_cpu(rel->r_addend);
529#endif
530 }
531 }
532}
533
534
535static void print_absolute_symbols(void)
536{
537 int i;
538 const char *format;
539
540 if (ELF_BITS == 64)
541 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
542 else
543 format = "%5d %08"PRIx32" %5"PRId32" %10s %10s %12s %s\n";
544
545 printf("Absolute symbols\n");
546 printf(" Num: Value Size Type Bind Visibility Name\n");
547 for (i = 0; i < shnum; i++) {
548 struct section *sec = &secs[i];
549 char *sym_strtab;
550 int j;
551
552 if (sec->shdr.sh_type != SHT_SYMTAB) {
553 continue;
554 }
555 sym_strtab = sec->link->strtab;
556 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
557 Elf_Sym *sym;
558 const char *name;
559 sym = &sec->symtab[j];
560 name = sym_name(sym_strtab, sym);
561 if (sym->st_shndx != SHN_ABS) {
562 continue;
563 }
564 printf(format,
565 j, sym->st_value, sym->st_size,
566 sym_type(ELF_ST_TYPE(sym->st_info)),
567 sym_bind(ELF_ST_BIND(sym->st_info)),
568 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
569 name);
570 }
571 }
572 printf("\n");
573}
574
575static void print_absolute_relocs(void)
576{
577 int i, printed = 0;
578 const char *format;
579
580 if (ELF_BITS == 64)
581 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64" %s\n";
582 else
583 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
584
585 for (i = 0; i < shnum; i++) {
586 struct section *sec = &secs[i];
587 struct section *sec_applies, *sec_symtab;
588 char *sym_strtab;
589 Elf_Sym *sh_symtab;
590 int j;
591 if (sec->shdr.sh_type != SHT_REL_TYPE) {
592 continue;
593 }
594 sec_symtab = sec->link;
595 sec_applies = &secs[sec->shdr.sh_info];
596 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
597 continue;
598 }
599 sh_symtab = sec_symtab->symtab;
600 sym_strtab = sec_symtab->link->strtab;
601 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
602 Elf_Rel *rel;
603 Elf_Sym *sym;
604 const char *name;
605 rel = &sec->reltab[j];
606 sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
607 name = sym_name(sym_strtab, sym);
608 if (sym->st_shndx != SHN_ABS) {
609 continue;
610 }
611
612 /* Absolute symbols are not relocated if bzImage is
613 * loaded at a non-compiled address. Display a warning
614 * to user at compile time about the absolute
615 * relocations present.
616 *
617 * User need to audit the code to make sure
618 * some symbols which should have been section
619 * relative have not become absolute because of some
620 * linker optimization or wrong programming usage.
621 *
622 * Before warning check if this absolute symbol
623 * relocation is harmless.
624 */
625 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
626 continue;
627
628 if (!printed) {
629 printf("WARNING: Absolute relocations"
630 " present\n");
631 printf("Offset Info Type Sym.Value "
632 "Sym.Name\n");
633 printed = 1;
634 }
635
636 printf(format,
637 rel->r_offset,
638 rel->r_info,
639 rel_type(ELF_R_TYPE(rel->r_info)),
640 sym->st_value,
641 name);
642 }
643 }
644
645 if (printed)
646 printf("\n");
647}
648
649static void add_reloc(struct relocs *r, uint32_t offset)
650{
651 if (r->count == r->size) {
652 unsigned long newsize = r->size + 50000;
653 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
654
655 if (!mem)
656 die("realloc of %ld entries for relocs failed\n",
657 newsize);
658 r->offset = mem;
659 r->size = newsize;
660 }
661 r->offset[r->count++] = offset;
662}
663
664static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
665 Elf_Sym *sym, const char *symname))
666{
667 int i;
668 /* Walk through the relocations */
669 for (i = 0; i < shnum; i++) {
670 char *sym_strtab;
671 Elf_Sym *sh_symtab;
672 struct section *sec_applies, *sec_symtab;
673 int j;
674 struct section *sec = &secs[i];
675
676 if (sec->shdr.sh_type != SHT_REL_TYPE) {
677 continue;
678 }
679 sec_symtab = sec->link;
680 sec_applies = &secs[sec->shdr.sh_info];
681 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
682 continue;
683 }
684 sh_symtab = sec_symtab->symtab;
685 sym_strtab = sec_symtab->link->strtab;
686 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
687 Elf_Rel *rel = &sec->reltab[j];
688 Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
689 const char *symname = sym_name(sym_strtab, sym);
690
691 process(sec, rel, sym, symname);
692 }
693 }
694}
695
696/*
697 * The .data..percpu section is a special case for x86_64 SMP kernels.
698 * It is used to initialize the actual per_cpu areas and to provide
699 * definitions for the per_cpu variables that correspond to their offsets
700 * within the percpu area. Since the values of all of the symbols need
701 * to be offsets from the start of the per_cpu area the virtual address
702 * (sh_addr) of .data..percpu is 0 in SMP kernels.
703 *
704 * This means that:
705 *
706 * Relocations that reference symbols in the per_cpu area do not
707 * need further relocation (since the value is an offset relative
708 * to the start of the per_cpu area that does not change).
709 *
710 * Relocations that apply to the per_cpu area need to have their
711 * offset adjusted by by the value of __per_cpu_load to make them
712 * point to the correct place in the loaded image (because the
713 * virtual address of .data..percpu is 0).
714 *
715 * For non SMP kernels .data..percpu is linked as part of the normal
716 * kernel data and does not require special treatment.
717 *
718 */
719static int per_cpu_shndx = -1;
720static Elf_Addr per_cpu_load_addr;
721
722static void percpu_init(void)
723{
724 int i;
725 for (i = 0; i < shnum; i++) {
726 ElfW(Sym) *sym;
727 if (strcmp(sec_name(i), ".data..percpu"))
728 continue;
729
730 if (secs[i].shdr.sh_addr != 0) /* non SMP kernel */
731 return;
732
733 sym = sym_lookup("__per_cpu_load");
734 if (!sym)
735 die("can't find __per_cpu_load\n");
736
737 per_cpu_shndx = i;
738 per_cpu_load_addr = sym->st_value;
739 return;
740 }
741}
742
743#if ELF_BITS == 64
744
745/*
746 * Check to see if a symbol lies in the .data..percpu section.
747 *
748 * The linker incorrectly associates some symbols with the
749 * .data..percpu section so we also need to check the symbol
750 * name to make sure that we classify the symbol correctly.
751 *
752 * The GNU linker incorrectly associates:
753 * __init_begin
754 * __per_cpu_load
755 *
756 * The "gold" linker incorrectly associates:
757 * init_per_cpu__fixed_percpu_data
758 * init_per_cpu__gdt_page
759 */
760static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
761{
762 return (sym->st_shndx == per_cpu_shndx) &&
763 strcmp(symname, "__init_begin") &&
764 strcmp(symname, "__per_cpu_load") &&
765 strncmp(symname, "init_per_cpu_", 13);
766}
767
768
769static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
770 const char *symname)
771{
772 unsigned r_type = ELF64_R_TYPE(rel->r_info);
773 ElfW(Addr) offset = rel->r_offset;
774 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
775
776 if (sym->st_shndx == SHN_UNDEF)
777 return 0;
778
779 /*
780 * Adjust the offset if this reloc applies to the percpu section.
781 */
782 if (sec->shdr.sh_info == per_cpu_shndx)
783 offset += per_cpu_load_addr;
784
785 switch (r_type) {
786 case R_X86_64_NONE:
787 /* NONE can be ignored. */
788 break;
789
790 case R_X86_64_PC32:
791 case R_X86_64_PLT32:
792 /*
793 * PC relative relocations don't need to be adjusted unless
794 * referencing a percpu symbol.
795 *
796 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
797 */
798 if (is_percpu_sym(sym, symname))
799 add_reloc(&relocs32neg, offset);
800 break;
801
802 case R_X86_64_PC64:
803 /*
804 * Only used by jump labels
805 */
806 if (is_percpu_sym(sym, symname))
807 die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
808 symname);
809 break;
810
811 case R_X86_64_32:
812 case R_X86_64_32S:
813 case R_X86_64_64:
814 /*
815 * References to the percpu area don't need to be adjusted.
816 */
817 if (is_percpu_sym(sym, symname))
818 break;
819
820 if (shn_abs) {
821 /*
822 * Whitelisted absolute symbols do not require
823 * relocation.
824 */
825 if (is_reloc(S_ABS, symname))
826 break;
827
828 die("Invalid absolute %s relocation: %s\n",
829 rel_type(r_type), symname);
830 break;
831 }
832
833 /*
834 * Relocation offsets for 64 bit kernels are output
835 * as 32 bits and sign extended back to 64 bits when
836 * the relocations are processed.
837 * Make sure that the offset will fit.
838 */
839 if ((int32_t)offset != (int64_t)offset)
840 die("Relocation offset doesn't fit in 32 bits\n");
841
842 if (r_type == R_X86_64_64)
843 add_reloc(&relocs64, offset);
844 else
845 add_reloc(&relocs32, offset);
846 break;
847
848 default:
849 die("Unsupported relocation type: %s (%d)\n",
850 rel_type(r_type), r_type);
851 break;
852 }
853
854 return 0;
855}
856
857#else
858
859static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
860 const char *symname)
861{
862 unsigned r_type = ELF32_R_TYPE(rel->r_info);
863 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
864
865 switch (r_type) {
866 case R_386_NONE:
867 case R_386_PC32:
868 case R_386_PC16:
869 case R_386_PC8:
870 /*
871 * NONE can be ignored and PC relative relocations don't
872 * need to be adjusted.
873 */
874 break;
875
876 case R_386_32:
877 if (shn_abs) {
878 /*
879 * Whitelisted absolute symbols do not require
880 * relocation.
881 */
882 if (is_reloc(S_ABS, symname))
883 break;
884
885 die("Invalid absolute %s relocation: %s\n",
886 rel_type(r_type), symname);
887 break;
888 }
889
890 add_reloc(&relocs32, rel->r_offset);
891 break;
892
893 default:
894 die("Unsupported relocation type: %s (%d)\n",
895 rel_type(r_type), r_type);
896 break;
897 }
898
899 return 0;
900}
901
902static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
903 const char *symname)
904{
905 unsigned r_type = ELF32_R_TYPE(rel->r_info);
906 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
907
908 switch (r_type) {
909 case R_386_NONE:
910 case R_386_PC32:
911 case R_386_PC16:
912 case R_386_PC8:
913 /*
914 * NONE can be ignored and PC relative relocations don't
915 * need to be adjusted.
916 */
917 break;
918
919 case R_386_16:
920 if (shn_abs) {
921 /*
922 * Whitelisted absolute symbols do not require
923 * relocation.
924 */
925 if (is_reloc(S_ABS, symname))
926 break;
927
928 if (is_reloc(S_SEG, symname)) {
929 add_reloc(&relocs16, rel->r_offset);
930 break;
931 }
932 } else {
933 if (!is_reloc(S_LIN, symname))
934 break;
935 }
936 die("Invalid %s %s relocation: %s\n",
937 shn_abs ? "absolute" : "relative",
938 rel_type(r_type), symname);
939 break;
940
941 case R_386_32:
942 if (shn_abs) {
943 /*
944 * Whitelisted absolute symbols do not require
945 * relocation.
946 */
947 if (is_reloc(S_ABS, symname))
948 break;
949
950 if (is_reloc(S_REL, symname)) {
951 add_reloc(&relocs32, rel->r_offset);
952 break;
953 }
954 } else {
955 if (is_reloc(S_LIN, symname))
956 add_reloc(&relocs32, rel->r_offset);
957 break;
958 }
959 die("Invalid %s %s relocation: %s\n",
960 shn_abs ? "absolute" : "relative",
961 rel_type(r_type), symname);
962 break;
963
964 default:
965 die("Unsupported relocation type: %s (%d)\n",
966 rel_type(r_type), r_type);
967 break;
968 }
969
970 return 0;
971}
972
973#endif
974
975static int cmp_relocs(const void *va, const void *vb)
976{
977 const uint32_t *a, *b;
978 a = va; b = vb;
979 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
980}
981
982static void sort_relocs(struct relocs *r)
983{
984 qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
985}
986
987static int write32(uint32_t v, FILE *f)
988{
989 unsigned char buf[4];
990
991 put_unaligned_le32(v, buf);
992 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
993}
994
995static int write32_as_text(uint32_t v, FILE *f)
996{
997 return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
998}
999
1000static void emit_relocs(int as_text, int use_real_mode)
1001{
1002 int i;
1003 int (*write_reloc)(uint32_t, FILE *) = write32;
1004 int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
1005 const char *symname);
1006
1007#if ELF_BITS == 64
1008 if (!use_real_mode)
1009 do_reloc = do_reloc64;
1010 else
1011 die("--realmode not valid for a 64-bit ELF file");
1012#else
1013 if (!use_real_mode)
1014 do_reloc = do_reloc32;
1015 else
1016 do_reloc = do_reloc_real;
1017#endif
1018
1019 /* Collect up the relocations */
1020 walk_relocs(do_reloc);
1021
1022 if (relocs16.count && !use_real_mode)
1023 die("Segment relocations found but --realmode not specified\n");
1024
1025 /* Order the relocations for more efficient processing */
1026 sort_relocs(&relocs32);
1027#if ELF_BITS == 64
1028 sort_relocs(&relocs32neg);
1029 sort_relocs(&relocs64);
1030#else
1031 sort_relocs(&relocs16);
1032#endif
1033
1034 /* Print the relocations */
1035 if (as_text) {
1036 /* Print the relocations in a form suitable that
1037 * gas will like.
1038 */
1039 printf(".section \".data.reloc\",\"a\"\n");
1040 printf(".balign 4\n");
1041 write_reloc = write32_as_text;
1042 }
1043
1044 if (use_real_mode) {
1045 write_reloc(relocs16.count, stdout);
1046 for (i = 0; i < relocs16.count; i++)
1047 write_reloc(relocs16.offset[i], stdout);
1048
1049 write_reloc(relocs32.count, stdout);
1050 for (i = 0; i < relocs32.count; i++)
1051 write_reloc(relocs32.offset[i], stdout);
1052 } else {
1053#if ELF_BITS == 64
1054 /* Print a stop */
1055 write_reloc(0, stdout);
1056
1057 /* Now print each relocation */
1058 for (i = 0; i < relocs64.count; i++)
1059 write_reloc(relocs64.offset[i], stdout);
1060
1061 /* Print a stop */
1062 write_reloc(0, stdout);
1063
1064 /* Now print each inverse 32-bit relocation */
1065 for (i = 0; i < relocs32neg.count; i++)
1066 write_reloc(relocs32neg.offset[i], stdout);
1067#endif
1068
1069 /* Print a stop */
1070 write_reloc(0, stdout);
1071
1072 /* Now print each relocation */
1073 for (i = 0; i < relocs32.count; i++)
1074 write_reloc(relocs32.offset[i], stdout);
1075 }
1076}
1077
1078/*
1079 * As an aid to debugging problems with different linkers
1080 * print summary information about the relocs.
1081 * Since different linkers tend to emit the sections in
1082 * different orders we use the section names in the output.
1083 */
1084static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1085 const char *symname)
1086{
1087 printf("%s\t%s\t%s\t%s\n",
1088 sec_name(sec->shdr.sh_info),
1089 rel_type(ELF_R_TYPE(rel->r_info)),
1090 symname,
1091 sec_name(sym->st_shndx));
1092 return 0;
1093}
1094
1095static void print_reloc_info(void)
1096{
1097 printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1098 walk_relocs(do_reloc_info);
1099}
1100
1101#if ELF_BITS == 64
1102# define process process_64
1103#else
1104# define process process_32
1105#endif
1106
1107void process(FILE *fp, int use_real_mode, int as_text,
1108 int show_absolute_syms, int show_absolute_relocs,
1109 int show_reloc_info)
1110{
1111 regex_init(use_real_mode);
1112 read_ehdr(fp);
1113 read_shdrs(fp);
1114 read_strtabs(fp);
1115 read_symtabs(fp);
1116 read_relocs(fp);
1117 if (ELF_BITS == 64)
1118 percpu_init();
1119 if (show_absolute_syms) {
1120 print_absolute_symbols();
1121 return;
1122 }
1123 if (show_absolute_relocs) {
1124 print_absolute_relocs();
1125 return;
1126 }
1127 if (show_reloc_info) {
1128 print_reloc_info();
1129 return;
1130 }
1131 emit_relocs(as_text, use_real_mode);
1132}
1// SPDX-License-Identifier: GPL-2.0
2/* This is included from relocs_32/64.c */
3
4#define ElfW(type) _ElfW(ELF_BITS, type)
5#define _ElfW(bits, type) __ElfW(bits, type)
6#define __ElfW(bits, type) Elf##bits##_##type
7
8#define Elf_Addr ElfW(Addr)
9#define Elf_Ehdr ElfW(Ehdr)
10#define Elf_Phdr ElfW(Phdr)
11#define Elf_Shdr ElfW(Shdr)
12#define Elf_Sym ElfW(Sym)
13
14static Elf_Ehdr ehdr;
15static unsigned long shnum;
16static unsigned int shstrndx;
17static unsigned int shsymtabndx;
18static unsigned int shxsymtabndx;
19
20static int sym_index(Elf_Sym *sym);
21
22struct relocs {
23 uint32_t *offset;
24 unsigned long count;
25 unsigned long size;
26};
27
28static struct relocs relocs16;
29static struct relocs relocs32;
30#if ELF_BITS == 64
31static struct relocs relocs32neg;
32static struct relocs relocs64;
33#define FMT PRIu64
34#else
35#define FMT PRIu32
36#endif
37
38struct section {
39 Elf_Shdr shdr;
40 struct section *link;
41 Elf_Sym *symtab;
42 Elf32_Word *xsymtab;
43 Elf_Rel *reltab;
44 char *strtab;
45};
46static struct section *secs;
47
48static const char * const sym_regex_kernel[S_NSYMTYPES] = {
49/*
50 * Following symbols have been audited. There values are constant and do
51 * not change if bzImage is loaded at a different physical address than
52 * the address for which it has been compiled. Don't warn user about
53 * absolute relocations present w.r.t these symbols.
54 */
55 [S_ABS] =
56 "^(xen_irq_disable_direct_reloc$|"
57 "xen_save_fl_direct_reloc$|"
58 "VDSO|"
59 "__kcfi_typeid_|"
60 "__crc_)",
61
62/*
63 * These symbols are known to be relative, even if the linker marks them
64 * as absolute (typically defined outside any section in the linker script.)
65 */
66 [S_REL] =
67 "^(__init_(begin|end)|"
68 "__x86_cpu_dev_(start|end)|"
69 "__alt_instructions(_end)?|"
70 "(__iommu_table|__apicdrivers|__smp_locks)(_end)?|"
71 "__(start|end)_pci_.*|"
72#if CONFIG_FW_LOADER
73 "__(start|end)_builtin_fw|"
74#endif
75 "__(start|stop)___ksymtab(_gpl)?|"
76 "__(start|stop)___kcrctab(_gpl)?|"
77 "__(start|stop)___param|"
78 "__(start|stop)___modver|"
79 "__(start|stop)___bug_table|"
80 "__tracedata_(start|end)|"
81 "__(start|stop)_notes|"
82 "__end_rodata|"
83 "__end_rodata_aligned|"
84 "__initramfs_start|"
85 "(jiffies|jiffies_64)|"
86#if ELF_BITS == 64
87 "__per_cpu_load|"
88 "init_per_cpu__.*|"
89 "__end_rodata_hpage_align|"
90#endif
91 "__vvar_page|"
92 "_end)$"
93};
94
95
96static const char * const sym_regex_realmode[S_NSYMTYPES] = {
97/*
98 * These symbols are known to be relative, even if the linker marks them
99 * as absolute (typically defined outside any section in the linker script.)
100 */
101 [S_REL] =
102 "^pa_",
103
104/*
105 * These are 16-bit segment symbols when compiling 16-bit code.
106 */
107 [S_SEG] =
108 "^real_mode_seg$",
109
110/*
111 * These are offsets belonging to segments, as opposed to linear addresses,
112 * when compiling 16-bit code.
113 */
114 [S_LIN] =
115 "^pa_",
116};
117
118static const char * const *sym_regex;
119
120static regex_t sym_regex_c[S_NSYMTYPES];
121static int is_reloc(enum symtype type, const char *sym_name)
122{
123 return sym_regex[type] &&
124 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
125}
126
127static void regex_init(int use_real_mode)
128{
129 char errbuf[128];
130 int err;
131 int i;
132
133 if (use_real_mode)
134 sym_regex = sym_regex_realmode;
135 else
136 sym_regex = sym_regex_kernel;
137
138 for (i = 0; i < S_NSYMTYPES; i++) {
139 if (!sym_regex[i])
140 continue;
141
142 err = regcomp(&sym_regex_c[i], sym_regex[i],
143 REG_EXTENDED|REG_NOSUB);
144
145 if (err) {
146 regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf));
147 die("%s", errbuf);
148 }
149 }
150}
151
152static const char *sym_type(unsigned type)
153{
154 static const char *type_name[] = {
155#define SYM_TYPE(X) [X] = #X
156 SYM_TYPE(STT_NOTYPE),
157 SYM_TYPE(STT_OBJECT),
158 SYM_TYPE(STT_FUNC),
159 SYM_TYPE(STT_SECTION),
160 SYM_TYPE(STT_FILE),
161 SYM_TYPE(STT_COMMON),
162 SYM_TYPE(STT_TLS),
163#undef SYM_TYPE
164 };
165 const char *name = "unknown sym type name";
166 if (type < ARRAY_SIZE(type_name)) {
167 name = type_name[type];
168 }
169 return name;
170}
171
172static const char *sym_bind(unsigned bind)
173{
174 static const char *bind_name[] = {
175#define SYM_BIND(X) [X] = #X
176 SYM_BIND(STB_LOCAL),
177 SYM_BIND(STB_GLOBAL),
178 SYM_BIND(STB_WEAK),
179#undef SYM_BIND
180 };
181 const char *name = "unknown sym bind name";
182 if (bind < ARRAY_SIZE(bind_name)) {
183 name = bind_name[bind];
184 }
185 return name;
186}
187
188static const char *sym_visibility(unsigned visibility)
189{
190 static const char *visibility_name[] = {
191#define SYM_VISIBILITY(X) [X] = #X
192 SYM_VISIBILITY(STV_DEFAULT),
193 SYM_VISIBILITY(STV_INTERNAL),
194 SYM_VISIBILITY(STV_HIDDEN),
195 SYM_VISIBILITY(STV_PROTECTED),
196#undef SYM_VISIBILITY
197 };
198 const char *name = "unknown sym visibility name";
199 if (visibility < ARRAY_SIZE(visibility_name)) {
200 name = visibility_name[visibility];
201 }
202 return name;
203}
204
205static const char *rel_type(unsigned type)
206{
207 static const char *type_name[] = {
208#define REL_TYPE(X) [X] = #X
209#if ELF_BITS == 64
210 REL_TYPE(R_X86_64_NONE),
211 REL_TYPE(R_X86_64_64),
212 REL_TYPE(R_X86_64_PC64),
213 REL_TYPE(R_X86_64_PC32),
214 REL_TYPE(R_X86_64_GOT32),
215 REL_TYPE(R_X86_64_PLT32),
216 REL_TYPE(R_X86_64_COPY),
217 REL_TYPE(R_X86_64_GLOB_DAT),
218 REL_TYPE(R_X86_64_JUMP_SLOT),
219 REL_TYPE(R_X86_64_RELATIVE),
220 REL_TYPE(R_X86_64_GOTPCREL),
221 REL_TYPE(R_X86_64_32),
222 REL_TYPE(R_X86_64_32S),
223 REL_TYPE(R_X86_64_16),
224 REL_TYPE(R_X86_64_PC16),
225 REL_TYPE(R_X86_64_8),
226 REL_TYPE(R_X86_64_PC8),
227#else
228 REL_TYPE(R_386_NONE),
229 REL_TYPE(R_386_32),
230 REL_TYPE(R_386_PC32),
231 REL_TYPE(R_386_GOT32),
232 REL_TYPE(R_386_PLT32),
233 REL_TYPE(R_386_COPY),
234 REL_TYPE(R_386_GLOB_DAT),
235 REL_TYPE(R_386_JMP_SLOT),
236 REL_TYPE(R_386_RELATIVE),
237 REL_TYPE(R_386_GOTOFF),
238 REL_TYPE(R_386_GOTPC),
239 REL_TYPE(R_386_8),
240 REL_TYPE(R_386_PC8),
241 REL_TYPE(R_386_16),
242 REL_TYPE(R_386_PC16),
243#endif
244#undef REL_TYPE
245 };
246 const char *name = "unknown type rel type name";
247 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
248 name = type_name[type];
249 }
250 return name;
251}
252
253static const char *sec_name(unsigned shndx)
254{
255 const char *sec_strtab;
256 const char *name;
257 sec_strtab = secs[shstrndx].strtab;
258 name = "<noname>";
259 if (shndx < shnum) {
260 name = sec_strtab + secs[shndx].shdr.sh_name;
261 }
262 else if (shndx == SHN_ABS) {
263 name = "ABSOLUTE";
264 }
265 else if (shndx == SHN_COMMON) {
266 name = "COMMON";
267 }
268 return name;
269}
270
271static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
272{
273 const char *name;
274 name = "<noname>";
275 if (sym->st_name) {
276 name = sym_strtab + sym->st_name;
277 }
278 else {
279 name = sec_name(sym_index(sym));
280 }
281 return name;
282}
283
284static Elf_Sym *sym_lookup(const char *symname)
285{
286 int i;
287 for (i = 0; i < shnum; i++) {
288 struct section *sec = &secs[i];
289 long nsyms;
290 char *strtab;
291 Elf_Sym *symtab;
292 Elf_Sym *sym;
293
294 if (sec->shdr.sh_type != SHT_SYMTAB)
295 continue;
296
297 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
298 symtab = sec->symtab;
299 strtab = sec->link->strtab;
300
301 for (sym = symtab; --nsyms >= 0; sym++) {
302 if (!sym->st_name)
303 continue;
304 if (strcmp(symname, strtab + sym->st_name) == 0)
305 return sym;
306 }
307 }
308 return 0;
309}
310
311#if BYTE_ORDER == LITTLE_ENDIAN
312#define le16_to_cpu(val) (val)
313#define le32_to_cpu(val) (val)
314#define le64_to_cpu(val) (val)
315#endif
316#if BYTE_ORDER == BIG_ENDIAN
317#define le16_to_cpu(val) bswap_16(val)
318#define le32_to_cpu(val) bswap_32(val)
319#define le64_to_cpu(val) bswap_64(val)
320#endif
321
322static uint16_t elf16_to_cpu(uint16_t val)
323{
324 return le16_to_cpu(val);
325}
326
327static uint32_t elf32_to_cpu(uint32_t val)
328{
329 return le32_to_cpu(val);
330}
331
332#define elf_half_to_cpu(x) elf16_to_cpu(x)
333#define elf_word_to_cpu(x) elf32_to_cpu(x)
334
335#if ELF_BITS == 64
336static uint64_t elf64_to_cpu(uint64_t val)
337{
338 return le64_to_cpu(val);
339}
340#define elf_addr_to_cpu(x) elf64_to_cpu(x)
341#define elf_off_to_cpu(x) elf64_to_cpu(x)
342#define elf_xword_to_cpu(x) elf64_to_cpu(x)
343#else
344#define elf_addr_to_cpu(x) elf32_to_cpu(x)
345#define elf_off_to_cpu(x) elf32_to_cpu(x)
346#define elf_xword_to_cpu(x) elf32_to_cpu(x)
347#endif
348
349static int sym_index(Elf_Sym *sym)
350{
351 Elf_Sym *symtab = secs[shsymtabndx].symtab;
352 Elf32_Word *xsymtab = secs[shxsymtabndx].xsymtab;
353 unsigned long offset;
354 int index;
355
356 if (sym->st_shndx != SHN_XINDEX)
357 return sym->st_shndx;
358
359 /* calculate offset of sym from head of table. */
360 offset = (unsigned long)sym - (unsigned long)symtab;
361 index = offset / sizeof(*sym);
362
363 return elf32_to_cpu(xsymtab[index]);
364}
365
366static void read_ehdr(FILE *fp)
367{
368 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
369 die("Cannot read ELF header: %s\n",
370 strerror(errno));
371 }
372 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
373 die("No ELF magic\n");
374 }
375 if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
376 die("Not a %d bit executable\n", ELF_BITS);
377 }
378 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
379 die("Not a LSB ELF executable\n");
380 }
381 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
382 die("Unknown ELF version\n");
383 }
384 /* Convert the fields to native endian */
385 ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
386 ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
387 ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
388 ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
389 ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
390 ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
391 ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
392 ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
393 ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
394 ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
395 ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
396 ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
397 ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
398
399 shnum = ehdr.e_shnum;
400 shstrndx = ehdr.e_shstrndx;
401
402 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
403 die("Unsupported ELF header type\n");
404 if (ehdr.e_machine != ELF_MACHINE)
405 die("Not for %s\n", ELF_MACHINE_NAME);
406 if (ehdr.e_version != EV_CURRENT)
407 die("Unknown ELF version\n");
408 if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
409 die("Bad ELF header size\n");
410 if (ehdr.e_phentsize != sizeof(Elf_Phdr))
411 die("Bad program header entry\n");
412 if (ehdr.e_shentsize != sizeof(Elf_Shdr))
413 die("Bad section header entry\n");
414
415
416 if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
417 Elf_Shdr shdr;
418
419 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
420 die("Seek to %" FMT " failed: %s\n", ehdr.e_shoff, strerror(errno));
421
422 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
423 die("Cannot read initial ELF section header: %s\n", strerror(errno));
424
425 if (shnum == SHN_UNDEF)
426 shnum = elf_xword_to_cpu(shdr.sh_size);
427
428 if (shstrndx == SHN_XINDEX)
429 shstrndx = elf_word_to_cpu(shdr.sh_link);
430 }
431
432 if (shstrndx >= shnum)
433 die("String table index out of bounds\n");
434}
435
436static void read_shdrs(FILE *fp)
437{
438 int i;
439 Elf_Shdr shdr;
440
441 secs = calloc(shnum, sizeof(struct section));
442 if (!secs) {
443 die("Unable to allocate %ld section headers\n",
444 shnum);
445 }
446 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
447 die("Seek to %" FMT " failed: %s\n",
448 ehdr.e_shoff, strerror(errno));
449 }
450 for (i = 0; i < shnum; i++) {
451 struct section *sec = &secs[i];
452 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
453 die("Cannot read ELF section headers %d/%ld: %s\n",
454 i, shnum, strerror(errno));
455 sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
456 sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
457 sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
458 sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
459 sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
460 sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
461 sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
462 sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
463 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
464 sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
465 if (sec->shdr.sh_link < shnum)
466 sec->link = &secs[sec->shdr.sh_link];
467 }
468
469}
470
471static void read_strtabs(FILE *fp)
472{
473 int i;
474 for (i = 0; i < shnum; i++) {
475 struct section *sec = &secs[i];
476 if (sec->shdr.sh_type != SHT_STRTAB) {
477 continue;
478 }
479 sec->strtab = malloc(sec->shdr.sh_size);
480 if (!sec->strtab) {
481 die("malloc of %" FMT " bytes for strtab failed\n",
482 sec->shdr.sh_size);
483 }
484 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
485 die("Seek to %" FMT " failed: %s\n",
486 sec->shdr.sh_offset, strerror(errno));
487 }
488 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
489 != sec->shdr.sh_size) {
490 die("Cannot read symbol table: %s\n",
491 strerror(errno));
492 }
493 }
494}
495
496static void read_symtabs(FILE *fp)
497{
498 int i,j;
499
500 for (i = 0; i < shnum; i++) {
501 struct section *sec = &secs[i];
502 int num_syms;
503
504 switch (sec->shdr.sh_type) {
505 case SHT_SYMTAB_SHNDX:
506 sec->xsymtab = malloc(sec->shdr.sh_size);
507 if (!sec->xsymtab) {
508 die("malloc of %" FMT " bytes for xsymtab failed\n",
509 sec->shdr.sh_size);
510 }
511 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
512 die("Seek to %" FMT " failed: %s\n",
513 sec->shdr.sh_offset, strerror(errno));
514 }
515 if (fread(sec->xsymtab, 1, sec->shdr.sh_size, fp)
516 != sec->shdr.sh_size) {
517 die("Cannot read extended symbol table: %s\n",
518 strerror(errno));
519 }
520 shxsymtabndx = i;
521 continue;
522
523 case SHT_SYMTAB:
524 num_syms = sec->shdr.sh_size / sizeof(Elf_Sym);
525
526 sec->symtab = malloc(sec->shdr.sh_size);
527 if (!sec->symtab) {
528 die("malloc of %" FMT " bytes for symtab failed\n",
529 sec->shdr.sh_size);
530 }
531 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
532 die("Seek to %" FMT " failed: %s\n",
533 sec->shdr.sh_offset, strerror(errno));
534 }
535 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
536 != sec->shdr.sh_size) {
537 die("Cannot read symbol table: %s\n",
538 strerror(errno));
539 }
540 for (j = 0; j < num_syms; j++) {
541 Elf_Sym *sym = &sec->symtab[j];
542
543 sym->st_name = elf_word_to_cpu(sym->st_name);
544 sym->st_value = elf_addr_to_cpu(sym->st_value);
545 sym->st_size = elf_xword_to_cpu(sym->st_size);
546 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
547 }
548 shsymtabndx = i;
549 continue;
550
551 default:
552 continue;
553 }
554 }
555}
556
557
558static void read_relocs(FILE *fp)
559{
560 int i,j;
561 for (i = 0; i < shnum; i++) {
562 struct section *sec = &secs[i];
563 if (sec->shdr.sh_type != SHT_REL_TYPE) {
564 continue;
565 }
566 sec->reltab = malloc(sec->shdr.sh_size);
567 if (!sec->reltab) {
568 die("malloc of %" FMT " bytes for relocs failed\n",
569 sec->shdr.sh_size);
570 }
571 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
572 die("Seek to %" FMT " failed: %s\n",
573 sec->shdr.sh_offset, strerror(errno));
574 }
575 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
576 != sec->shdr.sh_size) {
577 die("Cannot read symbol table: %s\n",
578 strerror(errno));
579 }
580 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
581 Elf_Rel *rel = &sec->reltab[j];
582 rel->r_offset = elf_addr_to_cpu(rel->r_offset);
583 rel->r_info = elf_xword_to_cpu(rel->r_info);
584#if (SHT_REL_TYPE == SHT_RELA)
585 rel->r_addend = elf_xword_to_cpu(rel->r_addend);
586#endif
587 }
588 }
589}
590
591
592static void print_absolute_symbols(void)
593{
594 int i;
595 const char *format;
596
597 if (ELF_BITS == 64)
598 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
599 else
600 format = "%5d %08"PRIx32" %5"PRId32" %10s %10s %12s %s\n";
601
602 printf("Absolute symbols\n");
603 printf(" Num: Value Size Type Bind Visibility Name\n");
604 for (i = 0; i < shnum; i++) {
605 struct section *sec = &secs[i];
606 char *sym_strtab;
607 int j;
608
609 if (sec->shdr.sh_type != SHT_SYMTAB) {
610 continue;
611 }
612 sym_strtab = sec->link->strtab;
613 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
614 Elf_Sym *sym;
615 const char *name;
616 sym = &sec->symtab[j];
617 name = sym_name(sym_strtab, sym);
618 if (sym->st_shndx != SHN_ABS) {
619 continue;
620 }
621 printf(format,
622 j, sym->st_value, sym->st_size,
623 sym_type(ELF_ST_TYPE(sym->st_info)),
624 sym_bind(ELF_ST_BIND(sym->st_info)),
625 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
626 name);
627 }
628 }
629 printf("\n");
630}
631
632static void print_absolute_relocs(void)
633{
634 int i, printed = 0;
635 const char *format;
636
637 if (ELF_BITS == 64)
638 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64" %s\n";
639 else
640 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
641
642 for (i = 0; i < shnum; i++) {
643 struct section *sec = &secs[i];
644 struct section *sec_applies, *sec_symtab;
645 char *sym_strtab;
646 Elf_Sym *sh_symtab;
647 int j;
648 if (sec->shdr.sh_type != SHT_REL_TYPE) {
649 continue;
650 }
651 sec_symtab = sec->link;
652 sec_applies = &secs[sec->shdr.sh_info];
653 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
654 continue;
655 }
656 /*
657 * Do not perform relocations in .notes section; any
658 * values there are meant for pre-boot consumption (e.g.
659 * startup_xen).
660 */
661 if (sec_applies->shdr.sh_type == SHT_NOTE) {
662 continue;
663 }
664 sh_symtab = sec_symtab->symtab;
665 sym_strtab = sec_symtab->link->strtab;
666 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
667 Elf_Rel *rel;
668 Elf_Sym *sym;
669 const char *name;
670 rel = &sec->reltab[j];
671 sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
672 name = sym_name(sym_strtab, sym);
673 if (sym->st_shndx != SHN_ABS) {
674 continue;
675 }
676
677 /* Absolute symbols are not relocated if bzImage is
678 * loaded at a non-compiled address. Display a warning
679 * to user at compile time about the absolute
680 * relocations present.
681 *
682 * User need to audit the code to make sure
683 * some symbols which should have been section
684 * relative have not become absolute because of some
685 * linker optimization or wrong programming usage.
686 *
687 * Before warning check if this absolute symbol
688 * relocation is harmless.
689 */
690 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
691 continue;
692
693 if (!printed) {
694 printf("WARNING: Absolute relocations"
695 " present\n");
696 printf("Offset Info Type Sym.Value "
697 "Sym.Name\n");
698 printed = 1;
699 }
700
701 printf(format,
702 rel->r_offset,
703 rel->r_info,
704 rel_type(ELF_R_TYPE(rel->r_info)),
705 sym->st_value,
706 name);
707 }
708 }
709
710 if (printed)
711 printf("\n");
712}
713
714static void add_reloc(struct relocs *r, uint32_t offset)
715{
716 if (r->count == r->size) {
717 unsigned long newsize = r->size + 50000;
718 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
719
720 if (!mem)
721 die("realloc of %ld entries for relocs failed\n",
722 newsize);
723 r->offset = mem;
724 r->size = newsize;
725 }
726 r->offset[r->count++] = offset;
727}
728
729static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
730 Elf_Sym *sym, const char *symname))
731{
732 int i;
733 /* Walk through the relocations */
734 for (i = 0; i < shnum; i++) {
735 char *sym_strtab;
736 Elf_Sym *sh_symtab;
737 struct section *sec_applies, *sec_symtab;
738 int j;
739 struct section *sec = &secs[i];
740
741 if (sec->shdr.sh_type != SHT_REL_TYPE) {
742 continue;
743 }
744 sec_symtab = sec->link;
745 sec_applies = &secs[sec->shdr.sh_info];
746 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
747 continue;
748 }
749
750 /*
751 * Do not perform relocations in .notes sections; any
752 * values there are meant for pre-boot consumption (e.g.
753 * startup_xen).
754 */
755 if (sec_applies->shdr.sh_type == SHT_NOTE)
756 continue;
757
758 sh_symtab = sec_symtab->symtab;
759 sym_strtab = sec_symtab->link->strtab;
760 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
761 Elf_Rel *rel = &sec->reltab[j];
762 Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
763 const char *symname = sym_name(sym_strtab, sym);
764
765 process(sec, rel, sym, symname);
766 }
767 }
768}
769
770/*
771 * The .data..percpu section is a special case for x86_64 SMP kernels.
772 * It is used to initialize the actual per_cpu areas and to provide
773 * definitions for the per_cpu variables that correspond to their offsets
774 * within the percpu area. Since the values of all of the symbols need
775 * to be offsets from the start of the per_cpu area the virtual address
776 * (sh_addr) of .data..percpu is 0 in SMP kernels.
777 *
778 * This means that:
779 *
780 * Relocations that reference symbols in the per_cpu area do not
781 * need further relocation (since the value is an offset relative
782 * to the start of the per_cpu area that does not change).
783 *
784 * Relocations that apply to the per_cpu area need to have their
785 * offset adjusted by by the value of __per_cpu_load to make them
786 * point to the correct place in the loaded image (because the
787 * virtual address of .data..percpu is 0).
788 *
789 * For non SMP kernels .data..percpu is linked as part of the normal
790 * kernel data and does not require special treatment.
791 *
792 */
793static int per_cpu_shndx = -1;
794static Elf_Addr per_cpu_load_addr;
795
796static void percpu_init(void)
797{
798 int i;
799 for (i = 0; i < shnum; i++) {
800 ElfW(Sym) *sym;
801 if (strcmp(sec_name(i), ".data..percpu"))
802 continue;
803
804 if (secs[i].shdr.sh_addr != 0) /* non SMP kernel */
805 return;
806
807 sym = sym_lookup("__per_cpu_load");
808 if (!sym)
809 die("can't find __per_cpu_load\n");
810
811 per_cpu_shndx = i;
812 per_cpu_load_addr = sym->st_value;
813 return;
814 }
815}
816
817#if ELF_BITS == 64
818
819/*
820 * Check to see if a symbol lies in the .data..percpu section.
821 *
822 * The linker incorrectly associates some symbols with the
823 * .data..percpu section so we also need to check the symbol
824 * name to make sure that we classify the symbol correctly.
825 *
826 * The GNU linker incorrectly associates:
827 * __init_begin
828 * __per_cpu_load
829 *
830 * The "gold" linker incorrectly associates:
831 * init_per_cpu__fixed_percpu_data
832 * init_per_cpu__gdt_page
833 */
834static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
835{
836 int shndx = sym_index(sym);
837
838 return (shndx == per_cpu_shndx) &&
839 strcmp(symname, "__init_begin") &&
840 strcmp(symname, "__per_cpu_load") &&
841 strncmp(symname, "init_per_cpu_", 13);
842}
843
844
845static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
846 const char *symname)
847{
848 unsigned r_type = ELF64_R_TYPE(rel->r_info);
849 ElfW(Addr) offset = rel->r_offset;
850 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
851
852 if (sym->st_shndx == SHN_UNDEF)
853 return 0;
854
855 /*
856 * Adjust the offset if this reloc applies to the percpu section.
857 */
858 if (sec->shdr.sh_info == per_cpu_shndx)
859 offset += per_cpu_load_addr;
860
861 switch (r_type) {
862 case R_X86_64_NONE:
863 /* NONE can be ignored. */
864 break;
865
866 case R_X86_64_PC32:
867 case R_X86_64_PLT32:
868 /*
869 * PC relative relocations don't need to be adjusted unless
870 * referencing a percpu symbol.
871 *
872 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
873 */
874 if (is_percpu_sym(sym, symname))
875 add_reloc(&relocs32neg, offset);
876 break;
877
878 case R_X86_64_PC64:
879 /*
880 * Only used by jump labels
881 */
882 if (is_percpu_sym(sym, symname))
883 die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
884 symname);
885 break;
886
887 case R_X86_64_32:
888 case R_X86_64_32S:
889 case R_X86_64_64:
890 /*
891 * References to the percpu area don't need to be adjusted.
892 */
893 if (is_percpu_sym(sym, symname))
894 break;
895
896 if (shn_abs) {
897 /*
898 * Whitelisted absolute symbols do not require
899 * relocation.
900 */
901 if (is_reloc(S_ABS, symname))
902 break;
903
904 die("Invalid absolute %s relocation: %s\n",
905 rel_type(r_type), symname);
906 break;
907 }
908
909 /*
910 * Relocation offsets for 64 bit kernels are output
911 * as 32 bits and sign extended back to 64 bits when
912 * the relocations are processed.
913 * Make sure that the offset will fit.
914 */
915 if ((int32_t)offset != (int64_t)offset)
916 die("Relocation offset doesn't fit in 32 bits\n");
917
918 if (r_type == R_X86_64_64)
919 add_reloc(&relocs64, offset);
920 else
921 add_reloc(&relocs32, offset);
922 break;
923
924 default:
925 die("Unsupported relocation type: %s (%d)\n",
926 rel_type(r_type), r_type);
927 break;
928 }
929
930 return 0;
931}
932
933#else
934
935static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
936 const char *symname)
937{
938 unsigned r_type = ELF32_R_TYPE(rel->r_info);
939 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
940
941 switch (r_type) {
942 case R_386_NONE:
943 case R_386_PC32:
944 case R_386_PC16:
945 case R_386_PC8:
946 case R_386_PLT32:
947 /*
948 * NONE can be ignored and PC relative relocations don't need
949 * to be adjusted. Because sym must be defined, R_386_PLT32 can
950 * be treated the same way as R_386_PC32.
951 */
952 break;
953
954 case R_386_32:
955 if (shn_abs) {
956 /*
957 * Whitelisted absolute symbols do not require
958 * relocation.
959 */
960 if (is_reloc(S_ABS, symname))
961 break;
962
963 die("Invalid absolute %s relocation: %s\n",
964 rel_type(r_type), symname);
965 break;
966 }
967
968 add_reloc(&relocs32, rel->r_offset);
969 break;
970
971 default:
972 die("Unsupported relocation type: %s (%d)\n",
973 rel_type(r_type), r_type);
974 break;
975 }
976
977 return 0;
978}
979
980static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
981 const char *symname)
982{
983 unsigned r_type = ELF32_R_TYPE(rel->r_info);
984 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
985
986 switch (r_type) {
987 case R_386_NONE:
988 case R_386_PC32:
989 case R_386_PC16:
990 case R_386_PC8:
991 case R_386_PLT32:
992 /*
993 * NONE can be ignored and PC relative relocations don't need
994 * to be adjusted. Because sym must be defined, R_386_PLT32 can
995 * be treated the same way as R_386_PC32.
996 */
997 break;
998
999 case R_386_16:
1000 if (shn_abs) {
1001 /*
1002 * Whitelisted absolute symbols do not require
1003 * relocation.
1004 */
1005 if (is_reloc(S_ABS, symname))
1006 break;
1007
1008 if (is_reloc(S_SEG, symname)) {
1009 add_reloc(&relocs16, rel->r_offset);
1010 break;
1011 }
1012 } else {
1013 if (!is_reloc(S_LIN, symname))
1014 break;
1015 }
1016 die("Invalid %s %s relocation: %s\n",
1017 shn_abs ? "absolute" : "relative",
1018 rel_type(r_type), symname);
1019 break;
1020
1021 case R_386_32:
1022 if (shn_abs) {
1023 /*
1024 * Whitelisted absolute symbols do not require
1025 * relocation.
1026 */
1027 if (is_reloc(S_ABS, symname))
1028 break;
1029
1030 if (is_reloc(S_REL, symname)) {
1031 add_reloc(&relocs32, rel->r_offset);
1032 break;
1033 }
1034 } else {
1035 if (is_reloc(S_LIN, symname))
1036 add_reloc(&relocs32, rel->r_offset);
1037 break;
1038 }
1039 die("Invalid %s %s relocation: %s\n",
1040 shn_abs ? "absolute" : "relative",
1041 rel_type(r_type), symname);
1042 break;
1043
1044 default:
1045 die("Unsupported relocation type: %s (%d)\n",
1046 rel_type(r_type), r_type);
1047 break;
1048 }
1049
1050 return 0;
1051}
1052
1053#endif
1054
1055static int cmp_relocs(const void *va, const void *vb)
1056{
1057 const uint32_t *a, *b;
1058 a = va; b = vb;
1059 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
1060}
1061
1062static void sort_relocs(struct relocs *r)
1063{
1064 qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
1065}
1066
1067static int write32(uint32_t v, FILE *f)
1068{
1069 unsigned char buf[4];
1070
1071 put_unaligned_le32(v, buf);
1072 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
1073}
1074
1075static int write32_as_text(uint32_t v, FILE *f)
1076{
1077 return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
1078}
1079
1080static void emit_relocs(int as_text, int use_real_mode)
1081{
1082 int i;
1083 int (*write_reloc)(uint32_t, FILE *) = write32;
1084 int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
1085 const char *symname);
1086
1087#if ELF_BITS == 64
1088 if (!use_real_mode)
1089 do_reloc = do_reloc64;
1090 else
1091 die("--realmode not valid for a 64-bit ELF file");
1092#else
1093 if (!use_real_mode)
1094 do_reloc = do_reloc32;
1095 else
1096 do_reloc = do_reloc_real;
1097#endif
1098
1099 /* Collect up the relocations */
1100 walk_relocs(do_reloc);
1101
1102 if (relocs16.count && !use_real_mode)
1103 die("Segment relocations found but --realmode not specified\n");
1104
1105 /* Order the relocations for more efficient processing */
1106 sort_relocs(&relocs32);
1107#if ELF_BITS == 64
1108 sort_relocs(&relocs32neg);
1109 sort_relocs(&relocs64);
1110#else
1111 sort_relocs(&relocs16);
1112#endif
1113
1114 /* Print the relocations */
1115 if (as_text) {
1116 /* Print the relocations in a form suitable that
1117 * gas will like.
1118 */
1119 printf(".section \".data.reloc\",\"a\"\n");
1120 printf(".balign 4\n");
1121 write_reloc = write32_as_text;
1122 }
1123
1124 if (use_real_mode) {
1125 write_reloc(relocs16.count, stdout);
1126 for (i = 0; i < relocs16.count; i++)
1127 write_reloc(relocs16.offset[i], stdout);
1128
1129 write_reloc(relocs32.count, stdout);
1130 for (i = 0; i < relocs32.count; i++)
1131 write_reloc(relocs32.offset[i], stdout);
1132 } else {
1133#if ELF_BITS == 64
1134 /* Print a stop */
1135 write_reloc(0, stdout);
1136
1137 /* Now print each relocation */
1138 for (i = 0; i < relocs64.count; i++)
1139 write_reloc(relocs64.offset[i], stdout);
1140
1141 /* Print a stop */
1142 write_reloc(0, stdout);
1143
1144 /* Now print each inverse 32-bit relocation */
1145 for (i = 0; i < relocs32neg.count; i++)
1146 write_reloc(relocs32neg.offset[i], stdout);
1147#endif
1148
1149 /* Print a stop */
1150 write_reloc(0, stdout);
1151
1152 /* Now print each relocation */
1153 for (i = 0; i < relocs32.count; i++)
1154 write_reloc(relocs32.offset[i], stdout);
1155 }
1156}
1157
1158/*
1159 * As an aid to debugging problems with different linkers
1160 * print summary information about the relocs.
1161 * Since different linkers tend to emit the sections in
1162 * different orders we use the section names in the output.
1163 */
1164static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1165 const char *symname)
1166{
1167 printf("%s\t%s\t%s\t%s\n",
1168 sec_name(sec->shdr.sh_info),
1169 rel_type(ELF_R_TYPE(rel->r_info)),
1170 symname,
1171 sec_name(sym_index(sym)));
1172 return 0;
1173}
1174
1175static void print_reloc_info(void)
1176{
1177 printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1178 walk_relocs(do_reloc_info);
1179}
1180
1181#if ELF_BITS == 64
1182# define process process_64
1183#else
1184# define process process_32
1185#endif
1186
1187void process(FILE *fp, int use_real_mode, int as_text,
1188 int show_absolute_syms, int show_absolute_relocs,
1189 int show_reloc_info)
1190{
1191 regex_init(use_real_mode);
1192 read_ehdr(fp);
1193 read_shdrs(fp);
1194 read_strtabs(fp);
1195 read_symtabs(fp);
1196 read_relocs(fp);
1197 if (ELF_BITS == 64)
1198 percpu_init();
1199 if (show_absolute_syms) {
1200 print_absolute_symbols();
1201 return;
1202 }
1203 if (show_absolute_relocs) {
1204 print_absolute_relocs();
1205 return;
1206 }
1207 if (show_reloc_info) {
1208 print_reloc_info();
1209 return;
1210 }
1211 emit_relocs(as_text, use_real_mode);
1212}