1
2
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;
15
16struct relocs {
17 uint32_t *offset;
18 unsigned long count;
19 unsigned long size;
20};
21
22static struct relocs relocs;
23
24struct section {
25 Elf_Shdr shdr;
26 struct section *link;
27 Elf_Sym *symtab;
28 Elf_Rel *reltab;
29 char *strtab;
30 long shdr_offset;
31};
32static struct section *secs;
33
34static const char * const regex_sym_kernel = {
35
36 "^(__crc_)",
37};
38
39static regex_t sym_regex_c;
40
41static int regex_skip_reloc(const char *sym_name)
42{
43 return !regexec(&sym_regex_c, sym_name, 0, NULL, 0);
44}
45
46static void regex_init(void)
47{
48 char errbuf[128];
49 int err;
50
51 err = regcomp(&sym_regex_c, regex_sym_kernel,
52 REG_EXTENDED|REG_NOSUB);
53
54 if (err) {
55 regerror(err, &sym_regex_c, errbuf, sizeof(errbuf));
56 die("%s", errbuf);
57 }
58}
59
60static const char *rel_type(unsigned type)
61{
62 static const char * const type_name[] = {
63#define REL_TYPE(X)[X] = #X
64 REL_TYPE(R_MIPS_NONE),
65 REL_TYPE(R_MIPS_16),
66 REL_TYPE(R_MIPS_32),
67 REL_TYPE(R_MIPS_REL32),
68 REL_TYPE(R_MIPS_26),
69 REL_TYPE(R_MIPS_HI16),
70 REL_TYPE(R_MIPS_LO16),
71 REL_TYPE(R_MIPS_GPREL16),
72 REL_TYPE(R_MIPS_LITERAL),
73 REL_TYPE(R_MIPS_GOT16),
74 REL_TYPE(R_MIPS_PC16),
75 REL_TYPE(R_MIPS_CALL16),
76 REL_TYPE(R_MIPS_GPREL32),
77 REL_TYPE(R_MIPS_64),
78 REL_TYPE(R_MIPS_HIGHER),
79 REL_TYPE(R_MIPS_HIGHEST),
80 REL_TYPE(R_MIPS_PC21_S2),
81 REL_TYPE(R_MIPS_PC26_S2),
82#undef REL_TYPE
83 };
84 const char *name = "unknown type rel type name";
85
86 if (type < ARRAY_SIZE(type_name) && type_name[type])
87 name = type_name[type];
88 return name;
89}
90
91static const char *sec_name(unsigned shndx)
92{
93 const char *sec_strtab;
94 const char *name;
95
96 sec_strtab = secs[ehdr.e_shstrndx].strtab;
97 if (shndx < ehdr.e_shnum)
98 name = sec_strtab + secs[shndx].shdr.sh_name;
99 else if (shndx == SHN_ABS)
100 name = "ABSOLUTE";
101 else if (shndx == SHN_COMMON)
102 name = "COMMON";
103 else
104 name = "<noname>";
105 return name;
106}
107
108static struct section *sec_lookup(const char *secname)
109{
110 int i;
111
112 for (i = 0; i < ehdr.e_shnum; i++)
113 if (strcmp(secname, sec_name(i)) == 0)
114 return &secs[i];
115
116 return NULL;
117}
118
119static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
120{
121 const char *name;
122
123 if (sym->st_name)
124 name = sym_strtab + sym->st_name;
125 else
126 name = sec_name(sym->st_shndx);
127 return name;
128}
129
130#if BYTE_ORDER == LITTLE_ENDIAN
131#define le16_to_cpu(val) (val)
132#define le32_to_cpu(val) (val)
133#define le64_to_cpu(val) (val)
134#define be16_to_cpu(val) bswap_16(val)
135#define be32_to_cpu(val) bswap_32(val)
136#define be64_to_cpu(val) bswap_64(val)
137
138#define cpu_to_le16(val) (val)
139#define cpu_to_le32(val) (val)
140#define cpu_to_le64(val) (val)
141#define cpu_to_be16(val) bswap_16(val)
142#define cpu_to_be32(val) bswap_32(val)
143#define cpu_to_be64(val) bswap_64(val)
144#endif
145#if BYTE_ORDER == BIG_ENDIAN
146#define le16_to_cpu(val) bswap_16(val)
147#define le32_to_cpu(val) bswap_32(val)
148#define le64_to_cpu(val) bswap_64(val)
149#define be16_to_cpu(val) (val)
150#define be32_to_cpu(val) (val)
151#define be64_to_cpu(val) (val)
152
153#define cpu_to_le16(val) bswap_16(val)
154#define cpu_to_le32(val) bswap_32(val)
155#define cpu_to_le64(val) bswap_64(val)
156#define cpu_to_be16(val) (val)
157#define cpu_to_be32(val) (val)
158#define cpu_to_be64(val) (val)
159#endif
160
161static uint16_t elf16_to_cpu(uint16_t val)
162{
163 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
164 return le16_to_cpu(val);
165 else
166 return be16_to_cpu(val);
167}
168
169static uint32_t elf32_to_cpu(uint32_t val)
170{
171 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
172 return le32_to_cpu(val);
173 else
174 return be32_to_cpu(val);
175}
176
177static uint32_t cpu_to_elf32(uint32_t val)
178{
179 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
180 return cpu_to_le32(val);
181 else
182 return cpu_to_be32(val);
183}
184
185#define elf_half_to_cpu(x) elf16_to_cpu(x)
186#define elf_word_to_cpu(x) elf32_to_cpu(x)
187
188#if ELF_BITS == 64
189static uint64_t elf64_to_cpu(uint64_t val)
190{
191 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
192 return le64_to_cpu(val);
193 else
194 return be64_to_cpu(val);
195}
196#define elf_addr_to_cpu(x) elf64_to_cpu(x)
197#define elf_off_to_cpu(x) elf64_to_cpu(x)
198#define elf_xword_to_cpu(x) elf64_to_cpu(x)
199#else
200#define elf_addr_to_cpu(x) elf32_to_cpu(x)
201#define elf_off_to_cpu(x) elf32_to_cpu(x)
202#define elf_xword_to_cpu(x) elf32_to_cpu(x)
203#endif
204
205static void read_ehdr(FILE *fp)
206{
207 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
208 die("Cannot read ELF header: %s\n", strerror(errno));
209
210 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0)
211 die("No ELF magic\n");
212
213 if (ehdr.e_ident[EI_CLASS] != ELF_CLASS)
214 die("Not a %d bit executable\n", ELF_BITS);
215
216 if ((ehdr.e_ident[EI_DATA] != ELFDATA2LSB) &&
217 (ehdr.e_ident[EI_DATA] != ELFDATA2MSB))
218 die("Unknown ELF Endianness\n");
219
220 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT)
221 die("Unknown ELF version\n");
222
223
224 ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
225 ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
226 ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
227 ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
228 ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
229 ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
230 ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
231 ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
232 ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
233 ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
234 ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
235 ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
236 ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
237
238 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
239 die("Unsupported ELF header type\n");
240
241 if (ehdr.e_machine != ELF_MACHINE)
242 die("Not for %s\n", ELF_MACHINE_NAME);
243
244 if (ehdr.e_version != EV_CURRENT)
245 die("Unknown ELF version\n");
246
247 if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
248 die("Bad Elf header size\n");
249
250 if (ehdr.e_phentsize != sizeof(Elf_Phdr))
251 die("Bad program header entry\n");
252
253 if (ehdr.e_shentsize != sizeof(Elf_Shdr))
254 die("Bad section header entry\n");
255
256 if (ehdr.e_shstrndx >= ehdr.e_shnum)
257 die("String table index out of bounds\n");
258}
259
260static void read_shdrs(FILE *fp)
261{
262 int i;
263 Elf_Shdr shdr;
264
265 secs = calloc(ehdr.e_shnum, sizeof(struct section));
266 if (!secs)
267 die("Unable to allocate %d section headers\n", ehdr.e_shnum);
268
269 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
270 die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));
271
272 for (i = 0; i < ehdr.e_shnum; i++) {
273 struct section *sec = &secs[i];
274
275 sec->shdr_offset = ftell(fp);
276 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
277 die("Cannot read ELF section headers %d/%d: %s\n",
278 i, ehdr.e_shnum, strerror(errno));
279 sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
280 sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
281 sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
282 sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
283 sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
284 sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
285 sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
286 sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
287 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
288 sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
289 if (sec->shdr.sh_link < ehdr.e_shnum)
290 sec->link = &secs[sec->shdr.sh_link];
291 }
292}
293
294static void read_strtabs(FILE *fp)
295{
296 int i;
297
298 for (i = 0; i < ehdr.e_shnum; i++) {
299 struct section *sec = &secs[i];
300
301 if (sec->shdr.sh_type != SHT_STRTAB)
302 continue;
303
304 sec->strtab = malloc(sec->shdr.sh_size);
305 if (!sec->strtab)
306 die("malloc of %d bytes for strtab failed\n",
307 sec->shdr.sh_size);
308
309 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
310 die("Seek to %d failed: %s\n",
311 sec->shdr.sh_offset, strerror(errno));
312
313 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp) !=
314 sec->shdr.sh_size)
315 die("Cannot read symbol table: %s\n", strerror(errno));
316 }
317}
318
319static void read_symtabs(FILE *fp)
320{
321 int i, j;
322
323 for (i = 0; i < ehdr.e_shnum; i++) {
324 struct section *sec = &secs[i];
325 if (sec->shdr.sh_type != SHT_SYMTAB)
326 continue;
327
328 sec->symtab = malloc(sec->shdr.sh_size);
329 if (!sec->symtab)
330 die("malloc of %d bytes for symtab failed\n",
331 sec->shdr.sh_size);
332
333 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
334 die("Seek to %d failed: %s\n",
335 sec->shdr.sh_offset, strerror(errno));
336
337 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) !=
338 sec->shdr.sh_size)
339 die("Cannot read symbol table: %s\n", strerror(errno));
340
341 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
342 Elf_Sym *sym = &sec->symtab[j];
343
344 sym->st_name = elf_word_to_cpu(sym->st_name);
345 sym->st_value = elf_addr_to_cpu(sym->st_value);
346 sym->st_size = elf_xword_to_cpu(sym->st_size);
347 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
348 }
349 }
350}
351
352static void read_relocs(FILE *fp)
353{
354 static unsigned long base = 0;
355 int i, j;
356
357 if (!base) {
358 struct section *sec = sec_lookup(".text");
359
360 if (!sec)
361 die("Could not find .text section\n");
362
363 base = sec->shdr.sh_addr;
364 }
365
366 for (i = 0; i < ehdr.e_shnum; i++) {
367 struct section *sec = &secs[i];
368
369 if (sec->shdr.sh_type != SHT_REL_TYPE)
370 continue;
371
372 sec->reltab = malloc(sec->shdr.sh_size);
373 if (!sec->reltab)
374 die("malloc of %d bytes for relocs failed\n",
375 sec->shdr.sh_size);
376
377 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
378 die("Seek to %d failed: %s\n",
379 sec->shdr.sh_offset, strerror(errno));
380
381 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp) !=
382 sec->shdr.sh_size)
383 die("Cannot read symbol table: %s\n", strerror(errno));
384
385 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
386 Elf_Rel *rel = &sec->reltab[j];
387
388 rel->r_offset = elf_addr_to_cpu(rel->r_offset);
389
390 rel->r_offset -= base;
391#if (ELF_BITS == 32)
392 rel->r_info = elf_xword_to_cpu(rel->r_info);
393#else
394
395
396
397 rel->r_info = rel->r_info;
398 ELF_R_SYM(rel->r_info) = elf32_to_cpu(ELF_R_SYM(rel->r_info));
399#endif
400#if (SHT_REL_TYPE == SHT_RELA)
401 rel->r_addend = elf_xword_to_cpu(rel->r_addend);
402#endif
403 }
404 }
405}
406
407static void remove_relocs(FILE *fp)
408{
409 int i;
410 Elf_Shdr shdr;
411
412 for (i = 0; i < ehdr.e_shnum; i++) {
413 struct section *sec = &secs[i];
414
415 if (sec->shdr.sh_type != SHT_REL_TYPE)
416 continue;
417
418 if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
419 die("Seek to %d failed: %s\n",
420 sec->shdr_offset, strerror(errno));
421
422 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
423 die("Cannot read ELF section headers %d/%d: %s\n",
424 i, ehdr.e_shnum, strerror(errno));
425
426
427
428
429
430 shdr.sh_size = 0;
431
432 if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
433 die("Seek to %d failed: %s\n",
434 sec->shdr_offset, strerror(errno));
435
436 if (fwrite(&shdr, sizeof(shdr), 1, fp) != 1)
437 die("Cannot write ELF section headers %d/%d: %s\n",
438 i, ehdr.e_shnum, strerror(errno));
439 }
440}
441
442static void add_reloc(struct relocs *r, uint32_t offset, unsigned type)
443{
444
445
446
447
448 offset >>= 2;
449 if (offset > 0x00FFFFFF)
450 die("Kernel image exceeds maximum size for relocation!\n");
451
452 offset = (offset & 0x00FFFFFF) | ((type & 0xFF) << 24);
453
454 if (r->count == r->size) {
455 unsigned long newsize = r->size + 50000;
456 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
457
458 if (!mem)
459 die("realloc failed\n");
460
461 r->offset = mem;
462 r->size = newsize;
463 }
464 r->offset[r->count++] = offset;
465}
466
467static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
468 Elf_Sym *sym, const char *symname))
469{
470 int i;
471
472
473 for (i = 0; i < ehdr.e_shnum; i++) {
474 char *sym_strtab;
475 Elf_Sym *sh_symtab;
476 struct section *sec_applies, *sec_symtab;
477 int j;
478 struct section *sec = &secs[i];
479
480 if (sec->shdr.sh_type != SHT_REL_TYPE)
481 continue;
482
483 sec_symtab = sec->link;
484 sec_applies = &secs[sec->shdr.sh_info];
485 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC))
486 continue;
487
488 sh_symtab = sec_symtab->symtab;
489 sym_strtab = sec_symtab->link->strtab;
490 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
491 Elf_Rel *rel = &sec->reltab[j];
492 Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
493 const char *symname = sym_name(sym_strtab, sym);
494
495 process(sec, rel, sym, symname);
496 }
497 }
498}
499
500static int do_reloc(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
501 const char *symname)
502{
503 unsigned r_type = ELF_R_TYPE(rel->r_info);
504 unsigned bind = ELF_ST_BIND(sym->st_info);
505
506 if ((bind == STB_WEAK) && (sym->st_value == 0)) {
507
508 return 0;
509 }
510
511 if (regex_skip_reloc(symname))
512 return 0;
513
514 switch (r_type) {
515 case R_MIPS_NONE:
516 case R_MIPS_REL32:
517 case R_MIPS_PC16:
518 case R_MIPS_PC21_S2:
519 case R_MIPS_PC26_S2:
520
521
522
523
524 case R_MIPS_HIGHEST:
525 case R_MIPS_HIGHER:
526
527
528
529 case R_MIPS_LO16:
530
531
532
533 break;
534
535 case R_MIPS_64:
536 case R_MIPS_32:
537 case R_MIPS_26:
538 case R_MIPS_HI16:
539 add_reloc(&relocs, rel->r_offset, r_type);
540 break;
541
542 default:
543 die("Unsupported relocation type: %s (%d)\n",
544 rel_type(r_type), r_type);
545 break;
546 }
547
548 return 0;
549}
550
551static int write_reloc_as_bin(uint32_t v, FILE *f)
552{
553 unsigned char buf[4];
554
555 v = cpu_to_elf32(v);
556
557 memcpy(buf, &v, sizeof(uint32_t));
558 return fwrite(buf, 1, 4, f);
559}
560
561static int write_reloc_as_text(uint32_t v, FILE *f)
562{
563 int res;
564
565 res = fprintf(f, "\t.long 0x%08"PRIx32"\n", v);
566 if (res < 0)
567 return res;
568 else
569 return sizeof(uint32_t);
570}
571
572static void emit_relocs(int as_text, int as_bin, FILE *outf)
573{
574 int i;
575 int (*write_reloc)(uint32_t, FILE *) = write_reloc_as_bin;
576 int size = 0;
577 int size_reserved;
578 struct section *sec_reloc;
579
580 sec_reloc = sec_lookup(".data.reloc");
581 if (!sec_reloc)
582 die("Could not find relocation section\n");
583
584 size_reserved = sec_reloc->shdr.sh_size;
585
586
587 walk_relocs(do_reloc);
588
589
590 if (as_text) {
591
592
593
594 printf(".section \".data.reloc\",\"a\"\n");
595 printf(".balign 4\n");
596
597 write_reloc = write_reloc_as_text;
598 outf = stdout;
599 } else if (as_bin) {
600
601 outf = stdout;
602 } else {
603
604
605
606
607 if (fseek(outf, sec_reloc->shdr.sh_offset, SEEK_SET) < 0) {
608 die("Seek to %d failed: %s\n",
609 sec_reloc->shdr.sh_offset, strerror(errno));
610 }
611 }
612
613 for (i = 0; i < relocs.count; i++)
614 size += write_reloc(relocs.offset[i], outf);
615
616
617 if (size)
618 size += write_reloc(0, outf);
619
620 if (size > size_reserved)
621
622
623
624
625 die("Relocations overflow available space!\n" \
626 "Please adjust CONFIG_RELOCATION_TABLE_SIZE " \
627 "to at least 0x%08x\n", (size + 0x1000) & ~0xFFF);
628}
629
630
631
632
633
634
635
636static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
637 const char *symname)
638{
639 printf("%16s 0x%08x %16s %40s %16s\n",
640 sec_name(sec->shdr.sh_info),
641 (unsigned int)rel->r_offset,
642 rel_type(ELF_R_TYPE(rel->r_info)),
643 symname,
644 sec_name(sym->st_shndx));
645 return 0;
646}
647
648static void print_reloc_info(void)
649{
650 printf("%16s %10s %16s %40s %16s\n",
651 "reloc section",
652 "offset",
653 "reloc type",
654 "symbol",
655 "symbol section");
656 walk_relocs(do_reloc_info);
657}
658
659#if ELF_BITS == 64
660# define process process_64
661#else
662# define process process_32
663#endif
664
665void process(FILE *fp, int as_text, int as_bin,
666 int show_reloc_info, int keep_relocs)
667{
668 regex_init();
669 read_ehdr(fp);
670 read_shdrs(fp);
671 read_strtabs(fp);
672 read_symtabs(fp);
673 read_relocs(fp);
674 if (show_reloc_info) {
675 print_reloc_info();
676 return;
677 }
678 emit_relocs(as_text, as_bin, fp);
679 if (!keep_relocs)
680 remove_relocs(fp);
681}
682
