13 #include <tools/le_byteshift.h>
15 static void die(char *fmt, ...);
17 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
18 static Elf32_Ehdr ehdr;
19 static unsigned long reloc_count, reloc_idx;
20 static unsigned long *relocs;
21 static unsigned long reloc16_count, reloc16_idx;
22 static unsigned long *relocs16;
31 static struct section *secs;
41 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
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.
49 "^(xen_irq_disable_direct_reloc$|"
50 "xen_save_fl_direct_reloc$|"
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.)
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|"
74 "(jiffies|jiffies_64)|"
79 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
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.)
88 * These are 16-bit segment symbols when compiling 16-bit code.
94 * These are offsets belonging to segments, as opposed to linear addresses,
95 * when compiling 16-bit code.
101 static const char * const *sym_regex;
103 static regex_t sym_regex_c[S_NSYMTYPES];
104 static int is_reloc(enum symtype type, const char *sym_name)
106 return sym_regex[type] &&
107 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
110 static void regex_init(int use_real_mode)
117 sym_regex = sym_regex_realmode;
119 sym_regex = sym_regex_kernel;
121 for (i = 0; i < S_NSYMTYPES; i++) {
125 err = regcomp(&sym_regex_c[i], sym_regex[i],
126 REG_EXTENDED|REG_NOSUB);
129 regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
135 static void die(char *fmt, ...)
139 vfprintf(stderr, fmt, ap);
144 static const char *sym_type(unsigned type)
146 static const char *type_name[] = {
147 #define SYM_TYPE(X) [X] = #X
148 SYM_TYPE(STT_NOTYPE),
149 SYM_TYPE(STT_OBJECT),
151 SYM_TYPE(STT_SECTION),
153 SYM_TYPE(STT_COMMON),
157 const char *name = "unknown sym type name";
158 if (type < ARRAY_SIZE(type_name)) {
159 name = type_name[type];
164 static const char *sym_bind(unsigned bind)
166 static const char *bind_name[] = {
167 #define SYM_BIND(X) [X] = #X
169 SYM_BIND(STB_GLOBAL),
173 const char *name = "unknown sym bind name";
174 if (bind < ARRAY_SIZE(bind_name)) {
175 name = bind_name[bind];
180 static const char *sym_visibility(unsigned visibility)
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
190 const char *name = "unknown sym visibility name";
191 if (visibility < ARRAY_SIZE(visibility_name)) {
192 name = visibility_name[visibility];
197 static const char *rel_type(unsigned type)
199 static const char *type_name[] = {
200 #define REL_TYPE(X) [X] = #X
201 REL_TYPE(R_386_NONE),
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),
215 REL_TYPE(R_386_PC16),
218 const char *name = "unknown type rel type name";
219 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
220 name = type_name[type];
225 static const char *sec_name(unsigned shndx)
227 const char *sec_strtab;
229 sec_strtab = secs[ehdr.e_shstrndx].strtab;
231 if (shndx < ehdr.e_shnum) {
232 name = sec_strtab + secs[shndx].shdr.sh_name;
234 else if (shndx == SHN_ABS) {
237 else if (shndx == SHN_COMMON) {
243 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
248 name = sym_strtab + sym->st_name;
251 name = sec_name(sym->st_shndx);
258 #if BYTE_ORDER == LITTLE_ENDIAN
259 #define le16_to_cpu(val) (val)
260 #define le32_to_cpu(val) (val)
262 #if BYTE_ORDER == BIG_ENDIAN
263 #define le16_to_cpu(val) bswap_16(val)
264 #define le32_to_cpu(val) bswap_32(val)
267 static uint16_t elf16_to_cpu(uint16_t val)
269 return le16_to_cpu(val);
272 static uint32_t elf32_to_cpu(uint32_t val)
274 return le32_to_cpu(val);
277 static void read_ehdr(FILE *fp)
279 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
280 die("Cannot read ELF header: %s\n",
283 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
284 die("No ELF magic\n");
286 if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
287 die("Not a 32 bit executable\n");
289 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
290 die("Not a LSB ELF executable\n");
292 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
293 die("Unknown ELF version\n");
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);
310 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
311 die("Unsupported ELF header type\n");
313 if (ehdr.e_machine != EM_386) {
314 die("Not for x86\n");
316 if (ehdr.e_version != EV_CURRENT) {
317 die("Unknown ELF version\n");
319 if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
320 die("Bad Elf header size\n");
322 if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
323 die("Bad program header entry\n");
325 if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
326 die("Bad section header entry\n");
328 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
329 die("String table index out of bounds\n");
333 static void read_shdrs(FILE *fp)
338 secs = calloc(ehdr.e_shnum, sizeof(struct section));
340 die("Unable to allocate %d section headers\n",
343 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
344 die("Seek to %d failed: %s\n",
345 ehdr.e_shoff, strerror(errno));
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];
368 static void read_strtabs(FILE *fp)
371 for (i = 0; i < ehdr.e_shnum; i++) {
372 struct section *sec = &secs[i];
373 if (sec->shdr.sh_type != SHT_STRTAB) {
376 sec->strtab = malloc(sec->shdr.sh_size);
378 die("malloc of %d bytes for strtab failed\n",
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));
385 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
386 != sec->shdr.sh_size) {
387 die("Cannot read symbol table: %s\n",
393 static void read_symtabs(FILE *fp)
396 for (i = 0; i < ehdr.e_shnum; i++) {
397 struct section *sec = &secs[i];
398 if (sec->shdr.sh_type != SHT_SYMTAB) {
401 sec->symtab = malloc(sec->shdr.sh_size);
403 die("malloc of %d bytes for symtab failed\n",
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));
410 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
411 != sec->shdr.sh_size) {
412 die("Cannot read symbol table: %s\n",
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);
426 static void read_relocs(FILE *fp)
429 for (i = 0; i < ehdr.e_shnum; i++) {
430 struct section *sec = &secs[i];
431 if (sec->shdr.sh_type != SHT_REL) {
434 sec->reltab = malloc(sec->shdr.sh_size);
436 die("malloc of %d bytes for relocs failed\n",
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));
443 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
444 != sec->shdr.sh_size) {
445 die("Cannot read symbol table: %s\n",
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);
457 static void print_absolute_symbols(void)
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];
467 if (sec->shdr.sh_type != SHT_SYMTAB) {
470 sym_strtab = sec->link->strtab;
471 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
474 sym = &sec->symtab[j];
475 name = sym_name(sym_strtab, sym);
476 if (sym->st_shndx != SHN_ABS) {
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)),
490 static void print_absolute_relocs(void)
494 for (i = 0; i < ehdr.e_shnum; i++) {
495 struct section *sec = &secs[i];
496 struct section *sec_applies, *sec_symtab;
498 Elf32_Sym *sh_symtab;
500 if (sec->shdr.sh_type != SHT_REL) {
503 sec_symtab = sec->link;
504 sec_applies = &secs[sec->shdr.sh_info];
505 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
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++) {
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) {
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.
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.
531 * Before warning check if this absolute symbol
532 * relocation is harmless.
534 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
538 printf("WARNING: Absolute relocations"
540 printf("Offset Info Type Sym.Value "
545 printf("%08x %08x %10s %08x %s\n",
548 rel_type(ELF32_R_TYPE(rel->r_info)),
558 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
562 /* Walk through the relocations */
563 for (i = 0; i < ehdr.e_shnum; i++) {
565 Elf32_Sym *sh_symtab;
566 struct section *sec_applies, *sec_symtab;
568 struct section *sec = &secs[i];
570 if (sec->shdr.sh_type != SHT_REL) {
573 sec_symtab = sec->link;
574 sec_applies = &secs[sec->shdr.sh_info];
575 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
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++) {
587 rel = &sec->reltab[j];
588 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
589 r_type = ELF32_R_TYPE(rel->r_info);
591 shn_abs = sym->st_shndx == SHN_ABS;
599 * NONE can be ignored and and PC relative
600 * relocations don't need to be adjusted.
605 symname = sym_name(sym_strtab, sym);
609 if (is_reloc(S_ABS, symname))
611 else if (!is_reloc(S_SEG, symname))
614 if (is_reloc(S_LIN, symname))
623 symname = sym_name(sym_strtab, sym);
625 if (is_reloc(S_ABS, symname))
627 else if (!is_reloc(S_REL, symname))
631 !is_reloc(S_LIN, symname))
637 die("Unsupported relocation type: %s (%d)\n",
638 rel_type(r_type), r_type);
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);
650 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
652 if (ELF32_R_TYPE(rel->r_info) == R_386_16)
658 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
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;
664 relocs[reloc_idx++] = rel->r_offset;
667 static int cmp_relocs(const void *va, const void *vb)
669 const unsigned long *a, *b;
671 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
674 static int write32(unsigned int v, FILE *f)
676 unsigned char buf[4];
678 put_unaligned_le32(v, buf);
679 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
682 static void emit_relocs(int as_text, int use_real_mode)
685 /* Count how many relocations I have and allocate space for them. */
687 walk_relocs(count_reloc, use_real_mode);
688 relocs = malloc(reloc_count * sizeof(relocs[0]));
690 die("malloc of %d entries for relocs failed\n",
694 relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
696 die("malloc of %d entries for relocs16 failed\n",
699 /* Collect up the relocations */
701 walk_relocs(collect_reloc, use_real_mode);
703 if (reloc16_count && !use_real_mode)
704 die("Segment relocations found but --realmode not specified\n");
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);
710 /* Print the relocations */
712 /* Print the relocations in a form suitable that
715 printf(".section \".data.reloc\",\"a\"\n");
716 printf(".balign 4\n");
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]);
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]);
737 write32(reloc16_count, stdout);
738 for (i = 0; i < reloc16_count; i++)
739 write32(relocs16[i], stdout);
740 write32(reloc_count, stdout);
742 /* Now print each relocation */
743 for (i = 0; i < reloc_count; i++)
744 write32(relocs[i], stdout);
749 /* Now print each relocation */
750 for (i = 0; i < reloc_count; i++) {
751 write32(relocs[i], stdout);
757 static void usage(void)
759 die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
762 int main(int argc, char **argv)
764 int show_absolute_syms, show_absolute_relocs;
765 int as_text, use_real_mode;
770 show_absolute_syms = 0;
771 show_absolute_relocs = 0;
775 for (i = 1; i < argc; i++) {
778 if (strcmp(arg, "--abs-syms") == 0) {
779 show_absolute_syms = 1;
782 if (strcmp(arg, "--abs-relocs") == 0) {
783 show_absolute_relocs = 1;
786 if (strcmp(arg, "--text") == 0) {
790 if (strcmp(arg, "--realmode") == 0) {
804 regex_init(use_real_mode);
805 fp = fopen(fname, "r");
807 die("Cannot open %s: %s\n",
808 fname, strerror(errno));
815 if (show_absolute_syms) {
816 print_absolute_symbols();
819 if (show_absolute_relocs) {
820 print_absolute_relocs();
823 emit_relocs(as_text, use_real_mode);