1 // SPDX-License-Identifier: GPL-2.0
2 /* This is included from relocs_32/64.c */
4 #define ElfW(type) _ElfW(ELF_BITS, type)
5 #define _ElfW(bits, type) __ElfW(bits, type)
6 #define __ElfW(bits, type) Elf##bits##_##type
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)
22 static struct relocs relocs;
32 static struct section *secs;
34 static const char * const regex_sym_kernel = {
35 /* Symbols matching these regex's should never be relocated */
39 static regex_t sym_regex_c;
41 static int regex_skip_reloc(const char *sym_name)
43 return !regexec(&sym_regex_c, sym_name, 0, NULL, 0);
46 static void regex_init(void)
51 err = regcomp(&sym_regex_c, regex_sym_kernel,
52 REG_EXTENDED|REG_NOSUB);
55 regerror(err, &sym_regex_c, errbuf, sizeof(errbuf));
60 static const char *rel_type(unsigned type)
62 static const char * const type_name[] = {
63 #define REL_TYPE(X)[X] = #X
64 REL_TYPE(R_MIPS_NONE),
67 REL_TYPE(R_MIPS_REL32),
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),
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),
84 const char *name = "unknown type rel type name";
86 if (type < ARRAY_SIZE(type_name) && type_name[type])
87 name = type_name[type];
91 static const char *sec_name(unsigned shndx)
93 const char *sec_strtab;
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)
101 else if (shndx == SHN_COMMON)
108 static struct section *sec_lookup(const char *secname)
112 for (i = 0; i < ehdr.e_shnum; i++)
113 if (strcmp(secname, sec_name(i)) == 0)
119 static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
124 name = sym_strtab + sym->st_name;
126 name = sec_name(sym->st_shndx);
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)
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)
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)
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)
161 static uint16_t elf16_to_cpu(uint16_t val)
163 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
164 return le16_to_cpu(val);
166 return be16_to_cpu(val);
169 static uint32_t elf32_to_cpu(uint32_t val)
171 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
172 return le32_to_cpu(val);
174 return be32_to_cpu(val);
177 static uint32_t cpu_to_elf32(uint32_t val)
179 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
180 return cpu_to_le32(val);
182 return cpu_to_be32(val);
185 #define elf_half_to_cpu(x) elf16_to_cpu(x)
186 #define elf_word_to_cpu(x) elf32_to_cpu(x)
189 static uint64_t elf64_to_cpu(uint64_t val)
191 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
192 return le64_to_cpu(val);
194 return be64_to_cpu(val);
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)
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)
205 static void read_ehdr(FILE *fp)
207 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
208 die("Cannot read ELF header: %s\n", strerror(errno));
210 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0)
211 die("No ELF magic\n");
213 if (ehdr.e_ident[EI_CLASS] != ELF_CLASS)
214 die("Not a %d bit executable\n", ELF_BITS);
216 if ((ehdr.e_ident[EI_DATA] != ELFDATA2LSB) &&
217 (ehdr.e_ident[EI_DATA] != ELFDATA2MSB))
218 die("Unknown ELF Endianness\n");
220 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT)
221 die("Unknown ELF version\n");
223 /* Convert the fields to native endian */
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);
238 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
239 die("Unsupported ELF header type\n");
241 if (ehdr.e_machine != ELF_MACHINE)
242 die("Not for %s\n", ELF_MACHINE_NAME);
244 if (ehdr.e_version != EV_CURRENT)
245 die("Unknown ELF version\n");
247 if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
248 die("Bad ELF header size\n");
250 if (ehdr.e_phentsize != sizeof(Elf_Phdr))
251 die("Bad program header entry\n");
253 if (ehdr.e_shentsize != sizeof(Elf_Shdr))
254 die("Bad section header entry\n");
256 if (ehdr.e_shstrndx >= ehdr.e_shnum)
257 die("String table index out of bounds\n");
260 static void read_shdrs(FILE *fp)
265 secs = calloc(ehdr.e_shnum, sizeof(struct section));
267 die("Unable to allocate %d section headers\n", ehdr.e_shnum);
269 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
270 die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));
272 for (i = 0; i < ehdr.e_shnum; i++) {
273 struct section *sec = &secs[i];
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];
294 static void read_strtabs(FILE *fp)
298 for (i = 0; i < ehdr.e_shnum; i++) {
299 struct section *sec = &secs[i];
301 if (sec->shdr.sh_type != SHT_STRTAB)
304 sec->strtab = malloc(sec->shdr.sh_size);
306 die("malloc of %d bytes for strtab failed\n",
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));
313 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp) !=
315 die("Cannot read symbol table: %s\n", strerror(errno));
319 static void read_symtabs(FILE *fp)
323 for (i = 0; i < ehdr.e_shnum; i++) {
324 struct section *sec = &secs[i];
325 if (sec->shdr.sh_type != SHT_SYMTAB)
328 sec->symtab = malloc(sec->shdr.sh_size);
330 die("malloc of %d bytes for symtab failed\n",
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));
337 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) !=
339 die("Cannot read symbol table: %s\n", strerror(errno));
341 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
342 Elf_Sym *sym = &sec->symtab[j];
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);
352 static void read_relocs(FILE *fp)
354 static unsigned long base;
358 struct section *sec = sec_lookup(".text");
361 die("Could not find .text section\n");
363 base = sec->shdr.sh_addr;
366 for (i = 0; i < ehdr.e_shnum; i++) {
367 struct section *sec = &secs[i];
369 if (sec->shdr.sh_type != SHT_REL_TYPE)
372 sec->reltab = malloc(sec->shdr.sh_size);
374 die("malloc of %d bytes for relocs failed\n",
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));
381 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp) !=
383 die("Cannot read symbol table: %s\n", strerror(errno));
385 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
386 Elf_Rel *rel = &sec->reltab[j];
388 rel->r_offset = elf_addr_to_cpu(rel->r_offset);
389 /* Set offset into kernel image */
390 rel->r_offset -= base;
392 rel->r_info = elf_xword_to_cpu(rel->r_info);
394 /* Convert MIPS64 RELA format - only the symbol
395 * index needs converting to native endianness
397 rel->r_info = rel->r_info;
398 ELF_R_SYM(rel->r_info) = elf32_to_cpu(ELF_R_SYM(rel->r_info));
400 #if (SHT_REL_TYPE == SHT_RELA)
401 rel->r_addend = elf_xword_to_cpu(rel->r_addend);
407 static void remove_relocs(FILE *fp)
412 for (i = 0; i < ehdr.e_shnum; i++) {
413 struct section *sec = &secs[i];
415 if (sec->shdr.sh_type != SHT_REL_TYPE)
418 if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
419 die("Seek to %d failed: %s\n",
420 sec->shdr_offset, strerror(errno));
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));
426 /* Set relocation section size to 0, effectively removing it.
427 * This is necessary due to lack of support for relocations
428 * in objcopy when creating 32bit elf from 64bit elf.
432 if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
433 die("Seek to %d failed: %s\n",
434 sec->shdr_offset, strerror(errno));
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));
442 static void add_reloc(struct relocs *r, uint32_t offset, unsigned type)
444 /* Relocation representation in binary table:
445 * |76543210|76543210|76543210|76543210|
446 * | Type | offset from _text >> 2 |
449 if (offset > 0x00FFFFFF)
450 die("Kernel image exceeds maximum size for relocation!\n");
452 offset = (offset & 0x00FFFFFF) | ((type & 0xFF) << 24);
454 if (r->count == r->size) {
455 unsigned long newsize = r->size + 50000;
456 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
459 die("realloc failed\n");
464 r->offset[r->count++] = offset;
467 static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
468 Elf_Sym *sym, const char *symname))
472 /* Walk through the relocations */
473 for (i = 0; i < ehdr.e_shnum; i++) {
476 struct section *sec_applies, *sec_symtab;
478 struct section *sec = &secs[i];
480 if (sec->shdr.sh_type != SHT_REL_TYPE)
483 sec_symtab = sec->link;
484 sec_applies = &secs[sec->shdr.sh_info];
485 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC))
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);
495 process(sec, rel, sym, symname);
500 static int do_reloc(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
503 unsigned r_type = ELF_R_TYPE(rel->r_info);
504 unsigned bind = ELF_ST_BIND(sym->st_info);
506 if ((bind == STB_WEAK) && (sym->st_value == 0)) {
507 /* Don't relocate weak symbols without a target */
511 if (regex_skip_reloc(symname))
521 * NONE can be ignored and PC relative relocations don't
522 * need to be adjusted.
526 /* We support relocating within the same 4Gb segment only,
527 * thus leaving the top 32bits unchanged
530 /* We support relocating by 64k jumps only
531 * thus leaving the bottom 16bits unchanged
539 add_reloc(&relocs, rel->r_offset, r_type);
543 die("Unsupported relocation type: %s (%d)\n",
544 rel_type(r_type), r_type);
551 static int write_reloc_as_bin(uint32_t v, FILE *f)
553 unsigned char buf[4];
557 memcpy(buf, &v, sizeof(uint32_t));
558 return fwrite(buf, 1, 4, f);
561 static int write_reloc_as_text(uint32_t v, FILE *f)
565 res = fprintf(f, "\t.long 0x%08"PRIx32"\n", v);
569 return sizeof(uint32_t);
572 static void emit_relocs(int as_text, int as_bin, FILE *outf)
575 int (*write_reloc)(uint32_t, FILE *) = write_reloc_as_bin;
578 struct section *sec_reloc;
580 sec_reloc = sec_lookup(".data.reloc");
582 die("Could not find relocation section\n");
584 size_reserved = sec_reloc->shdr.sh_size;
586 /* Collect up the relocations */
587 walk_relocs(do_reloc);
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 /* Output text to stdout */
597 write_reloc = write_reloc_as_text;
600 /* Output raw binary to stdout */
603 /* Seek to offset of the relocation section.
604 * Each relocation is then written into the
605 * vmlinux kernel image.
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));
613 for (i = 0; i < relocs.count; i++)
614 size += write_reloc(relocs.offset[i], outf);
616 /* Print a stop, but only if we've actually written some relocs */
618 size += write_reloc(0, outf);
620 if (size > size_reserved)
621 /* Die, but suggest a value for CONFIG_RELOCATION_TABLE_SIZE
622 * which will fix this problem and allow a bit of headroom
623 * if more kernel features are enabled
625 die("Relocations overflow available space!\n" \
626 "Please adjust CONFIG_RELOCATION_TABLE_SIZE " \
627 "to at least 0x%08x\n", (size + 0x1000) & ~0xFFF);
631 * As an aid to debugging problems with different linkers
632 * print summary information about the relocs.
633 * Since different linkers tend to emit the sections in
634 * different orders we use the section names in the output.
636 static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
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)),
644 sec_name(sym->st_shndx));
648 static void print_reloc_info(void)
650 printf("%16s %10s %16s %40s %16s\n",
656 walk_relocs(do_reloc_info);
660 # define process process_64
662 # define process process_32
665 void process(FILE *fp, int as_text, int as_bin,
666 int show_reloc_info, int keep_relocs)
674 if (show_reloc_info) {
678 emit_relocs(as_text, as_bin, fp);