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 are 16-bit segment symbols when compiling 16-bit code.
87 * These are offsets belonging to segments, as opposed to linear addresses,
88 * when compiling 16-bit code.
94 static const char * const *sym_regex;
96 static regex_t sym_regex_c[S_NSYMTYPES];
97 static int is_reloc(enum symtype type, const char *sym_name)
99 return sym_regex[type] &&
100 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
103 static void regex_init(int use_real_mode)
110 sym_regex = sym_regex_realmode;
112 sym_regex = sym_regex_kernel;
114 for (i = 0; i < S_NSYMTYPES; i++) {
118 err = regcomp(&sym_regex_c[i], sym_regex[i],
119 REG_EXTENDED|REG_NOSUB);
122 regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
128 static void die(char *fmt, ...)
132 vfprintf(stderr, fmt, ap);
137 static const char *sym_type(unsigned type)
139 static const char *type_name[] = {
140 #define SYM_TYPE(X) [X] = #X
141 SYM_TYPE(STT_NOTYPE),
142 SYM_TYPE(STT_OBJECT),
144 SYM_TYPE(STT_SECTION),
146 SYM_TYPE(STT_COMMON),
150 const char *name = "unknown sym type name";
151 if (type < ARRAY_SIZE(type_name)) {
152 name = type_name[type];
157 static const char *sym_bind(unsigned bind)
159 static const char *bind_name[] = {
160 #define SYM_BIND(X) [X] = #X
162 SYM_BIND(STB_GLOBAL),
166 const char *name = "unknown sym bind name";
167 if (bind < ARRAY_SIZE(bind_name)) {
168 name = bind_name[bind];
173 static const char *sym_visibility(unsigned visibility)
175 static const char *visibility_name[] = {
176 #define SYM_VISIBILITY(X) [X] = #X
177 SYM_VISIBILITY(STV_DEFAULT),
178 SYM_VISIBILITY(STV_INTERNAL),
179 SYM_VISIBILITY(STV_HIDDEN),
180 SYM_VISIBILITY(STV_PROTECTED),
181 #undef SYM_VISIBILITY
183 const char *name = "unknown sym visibility name";
184 if (visibility < ARRAY_SIZE(visibility_name)) {
185 name = visibility_name[visibility];
190 static const char *rel_type(unsigned type)
192 static const char *type_name[] = {
193 #define REL_TYPE(X) [X] = #X
194 REL_TYPE(R_386_NONE),
196 REL_TYPE(R_386_PC32),
197 REL_TYPE(R_386_GOT32),
198 REL_TYPE(R_386_PLT32),
199 REL_TYPE(R_386_COPY),
200 REL_TYPE(R_386_GLOB_DAT),
201 REL_TYPE(R_386_JMP_SLOT),
202 REL_TYPE(R_386_RELATIVE),
203 REL_TYPE(R_386_GOTOFF),
204 REL_TYPE(R_386_GOTPC),
208 REL_TYPE(R_386_PC16),
211 const char *name = "unknown type rel type name";
212 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
213 name = type_name[type];
218 static const char *sec_name(unsigned shndx)
220 const char *sec_strtab;
222 sec_strtab = secs[ehdr.e_shstrndx].strtab;
224 if (shndx < ehdr.e_shnum) {
225 name = sec_strtab + secs[shndx].shdr.sh_name;
227 else if (shndx == SHN_ABS) {
230 else if (shndx == SHN_COMMON) {
236 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
241 name = sym_strtab + sym->st_name;
244 name = sec_name(sym->st_shndx);
251 #if BYTE_ORDER == LITTLE_ENDIAN
252 #define le16_to_cpu(val) (val)
253 #define le32_to_cpu(val) (val)
255 #if BYTE_ORDER == BIG_ENDIAN
256 #define le16_to_cpu(val) bswap_16(val)
257 #define le32_to_cpu(val) bswap_32(val)
260 static uint16_t elf16_to_cpu(uint16_t val)
262 return le16_to_cpu(val);
265 static uint32_t elf32_to_cpu(uint32_t val)
267 return le32_to_cpu(val);
270 static void read_ehdr(FILE *fp)
272 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
273 die("Cannot read ELF header: %s\n",
276 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
277 die("No ELF magic\n");
279 if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
280 die("Not a 32 bit executable\n");
282 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
283 die("Not a LSB ELF executable\n");
285 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
286 die("Unknown ELF version\n");
288 /* Convert the fields to native endian */
289 ehdr.e_type = elf16_to_cpu(ehdr.e_type);
290 ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
291 ehdr.e_version = elf32_to_cpu(ehdr.e_version);
292 ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
293 ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
294 ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
295 ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
296 ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
297 ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
298 ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
299 ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
300 ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
301 ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
303 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
304 die("Unsupported ELF header type\n");
306 if (ehdr.e_machine != EM_386) {
307 die("Not for x86\n");
309 if (ehdr.e_version != EV_CURRENT) {
310 die("Unknown ELF version\n");
312 if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
313 die("Bad Elf header size\n");
315 if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
316 die("Bad program header entry\n");
318 if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
319 die("Bad section header entry\n");
321 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
322 die("String table index out of bounds\n");
326 static void read_shdrs(FILE *fp)
331 secs = calloc(ehdr.e_shnum, sizeof(struct section));
333 die("Unable to allocate %d section headers\n",
336 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
337 die("Seek to %d failed: %s\n",
338 ehdr.e_shoff, strerror(errno));
340 for (i = 0; i < ehdr.e_shnum; i++) {
341 struct section *sec = &secs[i];
342 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
343 die("Cannot read ELF section headers %d/%d: %s\n",
344 i, ehdr.e_shnum, strerror(errno));
345 sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name);
346 sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type);
347 sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags);
348 sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr);
349 sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset);
350 sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size);
351 sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link);
352 sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info);
353 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
354 sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize);
355 if (sec->shdr.sh_link < ehdr.e_shnum)
356 sec->link = &secs[sec->shdr.sh_link];
361 static void read_strtabs(FILE *fp)
364 for (i = 0; i < ehdr.e_shnum; i++) {
365 struct section *sec = &secs[i];
366 if (sec->shdr.sh_type != SHT_STRTAB) {
369 sec->strtab = malloc(sec->shdr.sh_size);
371 die("malloc of %d bytes for strtab failed\n",
374 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
375 die("Seek to %d failed: %s\n",
376 sec->shdr.sh_offset, strerror(errno));
378 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
379 != sec->shdr.sh_size) {
380 die("Cannot read symbol table: %s\n",
386 static void read_symtabs(FILE *fp)
389 for (i = 0; i < ehdr.e_shnum; i++) {
390 struct section *sec = &secs[i];
391 if (sec->shdr.sh_type != SHT_SYMTAB) {
394 sec->symtab = malloc(sec->shdr.sh_size);
396 die("malloc of %d bytes for symtab failed\n",
399 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
400 die("Seek to %d failed: %s\n",
401 sec->shdr.sh_offset, strerror(errno));
403 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
404 != sec->shdr.sh_size) {
405 die("Cannot read symbol table: %s\n",
408 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
409 Elf32_Sym *sym = &sec->symtab[j];
410 sym->st_name = elf32_to_cpu(sym->st_name);
411 sym->st_value = elf32_to_cpu(sym->st_value);
412 sym->st_size = elf32_to_cpu(sym->st_size);
413 sym->st_shndx = elf16_to_cpu(sym->st_shndx);
419 static void read_relocs(FILE *fp)
422 for (i = 0; i < ehdr.e_shnum; i++) {
423 struct section *sec = &secs[i];
424 if (sec->shdr.sh_type != SHT_REL) {
427 sec->reltab = malloc(sec->shdr.sh_size);
429 die("malloc of %d bytes for relocs failed\n",
432 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
433 die("Seek to %d failed: %s\n",
434 sec->shdr.sh_offset, strerror(errno));
436 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
437 != sec->shdr.sh_size) {
438 die("Cannot read symbol table: %s\n",
441 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
442 Elf32_Rel *rel = &sec->reltab[j];
443 rel->r_offset = elf32_to_cpu(rel->r_offset);
444 rel->r_info = elf32_to_cpu(rel->r_info);
450 static void print_absolute_symbols(void)
453 printf("Absolute symbols\n");
454 printf(" Num: Value Size Type Bind Visibility Name\n");
455 for (i = 0; i < ehdr.e_shnum; i++) {
456 struct section *sec = &secs[i];
460 if (sec->shdr.sh_type != SHT_SYMTAB) {
463 sym_strtab = sec->link->strtab;
464 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
467 sym = &sec->symtab[j];
468 name = sym_name(sym_strtab, sym);
469 if (sym->st_shndx != SHN_ABS) {
472 printf("%5d %08x %5d %10s %10s %12s %s\n",
473 j, sym->st_value, sym->st_size,
474 sym_type(ELF32_ST_TYPE(sym->st_info)),
475 sym_bind(ELF32_ST_BIND(sym->st_info)),
476 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
483 static void print_absolute_relocs(void)
487 for (i = 0; i < ehdr.e_shnum; i++) {
488 struct section *sec = &secs[i];
489 struct section *sec_applies, *sec_symtab;
491 Elf32_Sym *sh_symtab;
493 if (sec->shdr.sh_type != SHT_REL) {
496 sec_symtab = sec->link;
497 sec_applies = &secs[sec->shdr.sh_info];
498 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
501 sh_symtab = sec_symtab->symtab;
502 sym_strtab = sec_symtab->link->strtab;
503 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
507 rel = &sec->reltab[j];
508 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
509 name = sym_name(sym_strtab, sym);
510 if (sym->st_shndx != SHN_ABS) {
514 /* Absolute symbols are not relocated if bzImage is
515 * loaded at a non-compiled address. Display a warning
516 * to user at compile time about the absolute
517 * relocations present.
519 * User need to audit the code to make sure
520 * some symbols which should have been section
521 * relative have not become absolute because of some
522 * linker optimization or wrong programming usage.
524 * Before warning check if this absolute symbol
525 * relocation is harmless.
527 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
531 printf("WARNING: Absolute relocations"
533 printf("Offset Info Type Sym.Value "
538 printf("%08x %08x %10s %08x %s\n",
541 rel_type(ELF32_R_TYPE(rel->r_info)),
551 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
555 /* Walk through the relocations */
556 for (i = 0; i < ehdr.e_shnum; i++) {
558 Elf32_Sym *sh_symtab;
559 struct section *sec_applies, *sec_symtab;
561 struct section *sec = &secs[i];
563 if (sec->shdr.sh_type != SHT_REL) {
566 sec_symtab = sec->link;
567 sec_applies = &secs[sec->shdr.sh_info];
568 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
571 sh_symtab = sec_symtab->symtab;
572 sym_strtab = sec_symtab->link->strtab;
573 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
580 rel = &sec->reltab[j];
581 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
582 r_type = ELF32_R_TYPE(rel->r_info);
584 shn_abs = sym->st_shndx == SHN_ABS;
592 * NONE can be ignored and and PC relative
593 * relocations don't need to be adjusted.
598 symname = sym_name(sym_strtab, sym);
602 if (is_reloc(S_ABS, symname))
604 else if (!is_reloc(S_SEG, symname))
607 if (is_reloc(S_LIN, symname))
616 symname = sym_name(sym_strtab, sym);
618 if (is_reloc(S_ABS, symname))
620 else if (!is_reloc(S_REL, symname))
624 !is_reloc(S_LIN, symname))
630 die("Unsupported relocation type: %s (%d)\n",
631 rel_type(r_type), r_type);
634 symname = sym_name(sym_strtab, sym);
635 die("Invalid %s %s relocation: %s\n",
636 shn_abs ? "absolute" : "relative",
637 rel_type(r_type), symname);
643 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
645 if (ELF32_R_TYPE(rel->r_info) == R_386_16)
651 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
653 /* Remember the address that needs to be adjusted. */
654 if (ELF32_R_TYPE(rel->r_info) == R_386_16)
655 relocs16[reloc16_idx++] = rel->r_offset;
657 relocs[reloc_idx++] = rel->r_offset;
660 static int cmp_relocs(const void *va, const void *vb)
662 const unsigned long *a, *b;
664 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
667 static int write32(unsigned int v, FILE *f)
669 unsigned char buf[4];
671 put_unaligned_le32(v, buf);
672 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
675 static void emit_relocs(int as_text, int use_real_mode)
678 /* Count how many relocations I have and allocate space for them. */
680 walk_relocs(count_reloc, use_real_mode);
681 relocs = malloc(reloc_count * sizeof(relocs[0]));
683 die("malloc of %d entries for relocs failed\n",
687 relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
689 die("malloc of %d entries for relocs16 failed\n",
692 /* Collect up the relocations */
694 walk_relocs(collect_reloc, use_real_mode);
696 if (reloc16_count && !use_real_mode)
697 die("Segment relocations found but --realmode not specified\n");
699 /* Order the relocations for more efficient processing */
700 qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
701 qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
703 /* Print the relocations */
705 /* Print the relocations in a form suitable that
708 printf(".section \".data.reloc\",\"a\"\n");
709 printf(".balign 4\n");
711 printf("\t.long %lu\n", reloc16_count);
712 for (i = 0; i < reloc16_count; i++)
713 printf("\t.long 0x%08lx\n", relocs16[i]);
714 printf("\t.long %lu\n", reloc_count);
715 for (i = 0; i < reloc_count; i++) {
716 printf("\t.long 0x%08lx\n", relocs[i]);
720 printf("\t.long 0x%08lx\n", (unsigned long)0);
721 for (i = 0; i < reloc_count; i++) {
722 printf("\t.long 0x%08lx\n", relocs[i]);
730 write32(reloc16_count, stdout);
731 for (i = 0; i < reloc16_count; i++)
732 write32(relocs16[i], stdout);
733 write32(reloc_count, stdout);
735 /* Now print each relocation */
736 for (i = 0; i < reloc_count; i++)
737 write32(relocs[i], stdout);
742 /* Now print each relocation */
743 for (i = 0; i < reloc_count; i++) {
744 write32(relocs[i], stdout);
750 static void usage(void)
752 die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
755 int main(int argc, char **argv)
757 int show_absolute_syms, show_absolute_relocs;
758 int as_text, use_real_mode;
763 show_absolute_syms = 0;
764 show_absolute_relocs = 0;
768 for (i = 1; i < argc; i++) {
771 if (strcmp(arg, "--abs-syms") == 0) {
772 show_absolute_syms = 1;
775 if (strcmp(arg, "--abs-relocs") == 0) {
776 show_absolute_relocs = 1;
779 if (strcmp(arg, "--text") == 0) {
783 if (strcmp(arg, "--realmode") == 0) {
797 regex_init(use_real_mode);
798 fp = fopen(fname, "r");
800 die("Cannot open %s: %s\n",
801 fname, strerror(errno));
808 if (show_absolute_syms) {
809 print_absolute_symbols();
812 if (show_absolute_relocs) {
813 print_absolute_relocs();
816 emit_relocs(as_text, use_real_mode);