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