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;
29 static struct section *secs;
32 * Following symbols have been audited. There values are constant and do
33 * not change if bzImage is loaded at a different physical address than
34 * the address for which it has been compiled. Don't warn user about
35 * absolute relocations present w.r.t these symbols.
37 static const char abs_sym_regex[] =
38 "^(xen_irq_disable_direct_reloc$|"
39 "xen_save_fl_direct_reloc$|"
42 static regex_t abs_sym_regex_c;
43 static int is_abs_reloc(const char *sym_name)
45 return !regexec(&abs_sym_regex_c, sym_name, 0, NULL, 0);
49 * These symbols are known to be relative, even if the linker marks them
50 * as absolute (typically defined outside any section in the linker script.)
52 static const char rel_sym_regex[] =
54 static regex_t rel_sym_regex_c;
55 static int is_rel_reloc(const char *sym_name)
57 return !regexec(&rel_sym_regex_c, sym_name, 0, NULL, 0);
60 static void regex_init(void)
65 err = regcomp(&abs_sym_regex_c, abs_sym_regex,
66 REG_EXTENDED|REG_NOSUB);
68 regerror(err, &abs_sym_regex_c, errbuf, sizeof errbuf);
72 err = regcomp(&rel_sym_regex_c, rel_sym_regex,
73 REG_EXTENDED|REG_NOSUB);
75 regerror(err, &rel_sym_regex_c, errbuf, sizeof errbuf);
80 static void die(char *fmt, ...)
84 vfprintf(stderr, fmt, ap);
89 static const char *sym_type(unsigned type)
91 static const char *type_name[] = {
92 #define SYM_TYPE(X) [X] = #X
96 SYM_TYPE(STT_SECTION),
102 const char *name = "unknown sym type name";
103 if (type < ARRAY_SIZE(type_name)) {
104 name = type_name[type];
109 static const char *sym_bind(unsigned bind)
111 static const char *bind_name[] = {
112 #define SYM_BIND(X) [X] = #X
114 SYM_BIND(STB_GLOBAL),
118 const char *name = "unknown sym bind name";
119 if (bind < ARRAY_SIZE(bind_name)) {
120 name = bind_name[bind];
125 static const char *sym_visibility(unsigned visibility)
127 static const char *visibility_name[] = {
128 #define SYM_VISIBILITY(X) [X] = #X
129 SYM_VISIBILITY(STV_DEFAULT),
130 SYM_VISIBILITY(STV_INTERNAL),
131 SYM_VISIBILITY(STV_HIDDEN),
132 SYM_VISIBILITY(STV_PROTECTED),
133 #undef SYM_VISIBILITY
135 const char *name = "unknown sym visibility name";
136 if (visibility < ARRAY_SIZE(visibility_name)) {
137 name = visibility_name[visibility];
142 static const char *rel_type(unsigned type)
144 static const char *type_name[] = {
145 #define REL_TYPE(X) [X] = #X
146 REL_TYPE(R_386_NONE),
148 REL_TYPE(R_386_PC32),
149 REL_TYPE(R_386_GOT32),
150 REL_TYPE(R_386_PLT32),
151 REL_TYPE(R_386_COPY),
152 REL_TYPE(R_386_GLOB_DAT),
153 REL_TYPE(R_386_JMP_SLOT),
154 REL_TYPE(R_386_RELATIVE),
155 REL_TYPE(R_386_GOTOFF),
156 REL_TYPE(R_386_GOTPC),
159 const char *name = "unknown type rel type name";
160 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
161 name = type_name[type];
166 static const char *sec_name(unsigned shndx)
168 const char *sec_strtab;
170 sec_strtab = secs[ehdr.e_shstrndx].strtab;
172 if (shndx < ehdr.e_shnum) {
173 name = sec_strtab + secs[shndx].shdr.sh_name;
175 else if (shndx == SHN_ABS) {
178 else if (shndx == SHN_COMMON) {
184 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
189 name = sym_strtab + sym->st_name;
192 name = sec_name(secs[sym->st_shndx].shdr.sh_name);
199 #if BYTE_ORDER == LITTLE_ENDIAN
200 #define le16_to_cpu(val) (val)
201 #define le32_to_cpu(val) (val)
203 #if BYTE_ORDER == BIG_ENDIAN
204 #define le16_to_cpu(val) bswap_16(val)
205 #define le32_to_cpu(val) bswap_32(val)
208 static uint16_t elf16_to_cpu(uint16_t val)
210 return le16_to_cpu(val);
213 static uint32_t elf32_to_cpu(uint32_t val)
215 return le32_to_cpu(val);
218 static void read_ehdr(FILE *fp)
220 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
221 die("Cannot read ELF header: %s\n",
224 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
225 die("No ELF magic\n");
227 if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
228 die("Not a 32 bit executable\n");
230 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
231 die("Not a LSB ELF executable\n");
233 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
234 die("Unknown ELF version\n");
236 /* Convert the fields to native endian */
237 ehdr.e_type = elf16_to_cpu(ehdr.e_type);
238 ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
239 ehdr.e_version = elf32_to_cpu(ehdr.e_version);
240 ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
241 ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
242 ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
243 ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
244 ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
245 ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
246 ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
247 ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
248 ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
249 ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
251 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
252 die("Unsupported ELF header type\n");
254 if (ehdr.e_machine != EM_386) {
255 die("Not for x86\n");
257 if (ehdr.e_version != EV_CURRENT) {
258 die("Unknown ELF version\n");
260 if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
261 die("Bad Elf header size\n");
263 if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
264 die("Bad program header entry\n");
266 if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
267 die("Bad section header entry\n");
269 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
270 die("String table index out of bounds\n");
274 static void read_shdrs(FILE *fp)
279 secs = calloc(ehdr.e_shnum, sizeof(struct section));
281 die("Unable to allocate %d section headers\n",
284 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
285 die("Seek to %d failed: %s\n",
286 ehdr.e_shoff, strerror(errno));
288 for (i = 0; i < ehdr.e_shnum; i++) {
289 struct section *sec = &secs[i];
290 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
291 die("Cannot read ELF section headers %d/%d: %s\n",
292 i, ehdr.e_shnum, strerror(errno));
293 sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name);
294 sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type);
295 sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags);
296 sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr);
297 sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset);
298 sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size);
299 sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link);
300 sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info);
301 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
302 sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize);
303 if (sec->shdr.sh_link < ehdr.e_shnum)
304 sec->link = &secs[sec->shdr.sh_link];
309 static void read_strtabs(FILE *fp)
312 for (i = 0; i < ehdr.e_shnum; i++) {
313 struct section *sec = &secs[i];
314 if (sec->shdr.sh_type != SHT_STRTAB) {
317 sec->strtab = malloc(sec->shdr.sh_size);
319 die("malloc of %d bytes for strtab failed\n",
322 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
323 die("Seek to %d failed: %s\n",
324 sec->shdr.sh_offset, strerror(errno));
326 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
327 != sec->shdr.sh_size) {
328 die("Cannot read symbol table: %s\n",
334 static void read_symtabs(FILE *fp)
337 for (i = 0; i < ehdr.e_shnum; i++) {
338 struct section *sec = &secs[i];
339 if (sec->shdr.sh_type != SHT_SYMTAB) {
342 sec->symtab = malloc(sec->shdr.sh_size);
344 die("malloc of %d bytes for symtab failed\n",
347 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
348 die("Seek to %d failed: %s\n",
349 sec->shdr.sh_offset, strerror(errno));
351 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
352 != sec->shdr.sh_size) {
353 die("Cannot read symbol table: %s\n",
356 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
357 Elf32_Sym *sym = &sec->symtab[j];
358 sym->st_name = elf32_to_cpu(sym->st_name);
359 sym->st_value = elf32_to_cpu(sym->st_value);
360 sym->st_size = elf32_to_cpu(sym->st_size);
361 sym->st_shndx = elf16_to_cpu(sym->st_shndx);
367 static void read_relocs(FILE *fp)
370 for (i = 0; i < ehdr.e_shnum; i++) {
371 struct section *sec = &secs[i];
372 if (sec->shdr.sh_type != SHT_REL) {
375 sec->reltab = malloc(sec->shdr.sh_size);
377 die("malloc of %d bytes for relocs failed\n",
380 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
381 die("Seek to %d failed: %s\n",
382 sec->shdr.sh_offset, strerror(errno));
384 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
385 != sec->shdr.sh_size) {
386 die("Cannot read symbol table: %s\n",
389 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
390 Elf32_Rel *rel = &sec->reltab[j];
391 rel->r_offset = elf32_to_cpu(rel->r_offset);
392 rel->r_info = elf32_to_cpu(rel->r_info);
398 static void print_absolute_symbols(void)
401 printf("Absolute symbols\n");
402 printf(" Num: Value Size Type Bind Visibility Name\n");
403 for (i = 0; i < ehdr.e_shnum; i++) {
404 struct section *sec = &secs[i];
408 if (sec->shdr.sh_type != SHT_SYMTAB) {
411 sym_strtab = sec->link->strtab;
412 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
415 sym = &sec->symtab[j];
416 name = sym_name(sym_strtab, sym);
417 if (sym->st_shndx != SHN_ABS) {
420 printf("%5d %08x %5d %10s %10s %12s %s\n",
421 j, sym->st_value, sym->st_size,
422 sym_type(ELF32_ST_TYPE(sym->st_info)),
423 sym_bind(ELF32_ST_BIND(sym->st_info)),
424 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
431 static void print_absolute_relocs(void)
435 for (i = 0; i < ehdr.e_shnum; i++) {
436 struct section *sec = &secs[i];
437 struct section *sec_applies, *sec_symtab;
439 Elf32_Sym *sh_symtab;
441 if (sec->shdr.sh_type != SHT_REL) {
444 sec_symtab = sec->link;
445 sec_applies = &secs[sec->shdr.sh_info];
446 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
449 sh_symtab = sec_symtab->symtab;
450 sym_strtab = sec_symtab->link->strtab;
451 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
455 rel = &sec->reltab[j];
456 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
457 name = sym_name(sym_strtab, sym);
458 if (sym->st_shndx != SHN_ABS) {
462 /* Absolute symbols are not relocated if bzImage is
463 * loaded at a non-compiled address. Display a warning
464 * to user at compile time about the absolute
465 * relocations present.
467 * User need to audit the code to make sure
468 * some symbols which should have been section
469 * relative have not become absolute because of some
470 * linker optimization or wrong programming usage.
472 * Before warning check if this absolute symbol
473 * relocation is harmless.
475 if (is_abs_reloc(name) || is_rel_reloc(name))
479 printf("WARNING: Absolute relocations"
481 printf("Offset Info Type Sym.Value "
486 printf("%08x %08x %10s %08x %s\n",
489 rel_type(ELF32_R_TYPE(rel->r_info)),
499 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
502 /* Walk through the relocations */
503 for (i = 0; i < ehdr.e_shnum; i++) {
505 Elf32_Sym *sh_symtab;
506 struct section *sec_applies, *sec_symtab;
508 struct section *sec = &secs[i];
510 if (sec->shdr.sh_type != SHT_REL) {
513 sec_symtab = sec->link;
514 sec_applies = &secs[sec->shdr.sh_info];
515 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
518 sh_symtab = sec_symtab->symtab;
519 sym_strtab = sec_symtab->link->strtab;
520 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
524 rel = &sec->reltab[j];
525 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
526 r_type = ELF32_R_TYPE(rel->r_info);
527 /* Don't visit relocations to absolute symbols */
528 if (sym->st_shndx == SHN_ABS &&
529 !is_rel_reloc(sym_name(sym_strtab, sym))) {
536 * NONE can be ignored and and PC relative
537 * relocations don't need to be adjusted.
541 /* Visit relocations that need to be adjusted */
545 die("Unsupported relocation type: %s (%d)\n",
546 rel_type(r_type), r_type);
553 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
558 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
560 /* Remember the address that needs to be adjusted. */
561 relocs[reloc_idx++] = rel->r_offset;
564 static int cmp_relocs(const void *va, const void *vb)
566 const unsigned long *a, *b;
568 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
571 static void emit_relocs(int as_text)
574 /* Count how many relocations I have and allocate space for them. */
576 walk_relocs(count_reloc);
577 relocs = malloc(reloc_count * sizeof(relocs[0]));
579 die("malloc of %d entries for relocs failed\n",
582 /* Collect up the relocations */
584 walk_relocs(collect_reloc);
586 /* Order the relocations for more efficient processing */
587 qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
589 /* Print the relocations */
591 /* Print the relocations in a form suitable that
594 printf(".section \".data.reloc\",\"a\"\n");
595 printf(".balign 4\n");
596 for (i = 0; i < reloc_count; i++) {
597 printf("\t .long 0x%08lx\n", relocs[i]);
602 unsigned char buf[4];
604 fwrite("\0\0\0\0", 4, 1, stdout);
605 /* Now print each relocation */
606 for (i = 0; i < reloc_count; i++) {
607 put_unaligned_le32(relocs[i], buf);
608 fwrite(buf, 4, 1, stdout);
613 static void usage(void)
615 die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
618 int main(int argc, char **argv)
620 int show_absolute_syms, show_absolute_relocs;
628 show_absolute_syms = 0;
629 show_absolute_relocs = 0;
632 for (i = 1; i < argc; i++) {
635 if (strcmp(argv[1], "--abs-syms") == 0) {
636 show_absolute_syms = 1;
640 if (strcmp(argv[1], "--abs-relocs") == 0) {
641 show_absolute_relocs = 1;
644 else if (strcmp(argv[1], "--text") == 0) {
658 fp = fopen(fname, "r");
660 die("Cannot open %s: %s\n",
661 fname, strerror(errno));
668 if (show_absolute_syms) {
669 print_absolute_symbols();
672 if (show_absolute_relocs) {
673 print_absolute_relocs();
676 emit_relocs(as_text);