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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}
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}