diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-09-11 04:34:46 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-09-11 04:34:46 -0300 |
commit | 863981e96738983919de841ec669e157e6bdaeb0 (patch) | |
tree | d6d89a12e7eb8017837c057935a2271290907f76 /arch/mips/boot/tools/relocs.c | |
parent | 8dec7c70575785729a6a9e6719a955e9c545bcab (diff) |
Linux-libre 4.7.1-gnupck-4.7.1-gnu
Diffstat (limited to 'arch/mips/boot/tools/relocs.c')
-rw-r--r-- | arch/mips/boot/tools/relocs.c | 680 |
1 files changed, 680 insertions, 0 deletions
diff --git a/arch/mips/boot/tools/relocs.c b/arch/mips/boot/tools/relocs.c new file mode 100644 index 000000000..b9cbf7852 --- /dev/null +++ b/arch/mips/boot/tools/relocs.c @@ -0,0 +1,680 @@ +/* This is included from relocs_32/64.c */ + +#define ElfW(type) _ElfW(ELF_BITS, type) +#define _ElfW(bits, type) __ElfW(bits, type) +#define __ElfW(bits, type) Elf##bits##_##type + +#define Elf_Addr ElfW(Addr) +#define Elf_Ehdr ElfW(Ehdr) +#define Elf_Phdr ElfW(Phdr) +#define Elf_Shdr ElfW(Shdr) +#define Elf_Sym ElfW(Sym) + +static Elf_Ehdr ehdr; + +struct relocs { + uint32_t *offset; + unsigned long count; + unsigned long size; +}; + +static struct relocs relocs; + +struct section { + Elf_Shdr shdr; + struct section *link; + Elf_Sym *symtab; + Elf_Rel *reltab; + char *strtab; + long shdr_offset; +}; +static struct section *secs; + +static const char * const regex_sym_kernel = { +/* Symbols matching these regex's should never be relocated */ + "^(__crc_)", +}; + +static regex_t sym_regex_c; + +static int regex_skip_reloc(const char *sym_name) +{ + return !regexec(&sym_regex_c, sym_name, 0, NULL, 0); +} + +static void regex_init(void) +{ + char errbuf[128]; + int err; + + err = regcomp(&sym_regex_c, regex_sym_kernel, + REG_EXTENDED|REG_NOSUB); + + if (err) { + regerror(err, &sym_regex_c, errbuf, sizeof(errbuf)); + die("%s", errbuf); + } +} + +static const char *rel_type(unsigned type) +{ + static const char * const type_name[] = { +#define REL_TYPE(X)[X] = #X + REL_TYPE(R_MIPS_NONE), + REL_TYPE(R_MIPS_16), + REL_TYPE(R_MIPS_32), + REL_TYPE(R_MIPS_REL32), + REL_TYPE(R_MIPS_26), + REL_TYPE(R_MIPS_HI16), + REL_TYPE(R_MIPS_LO16), + REL_TYPE(R_MIPS_GPREL16), + REL_TYPE(R_MIPS_LITERAL), + REL_TYPE(R_MIPS_GOT16), + REL_TYPE(R_MIPS_PC16), + REL_TYPE(R_MIPS_CALL16), + REL_TYPE(R_MIPS_GPREL32), + REL_TYPE(R_MIPS_64), + REL_TYPE(R_MIPS_HIGHER), + REL_TYPE(R_MIPS_HIGHEST), + REL_TYPE(R_MIPS_PC21_S2), + REL_TYPE(R_MIPS_PC26_S2), +#undef REL_TYPE + }; + const char *name = "unknown type rel type name"; + + if (type < ARRAY_SIZE(type_name) && type_name[type]) + name = type_name[type]; + return name; +} + +static const char *sec_name(unsigned shndx) +{ + const char *sec_strtab; + const char *name; + + sec_strtab = secs[ehdr.e_shstrndx].strtab; + if (shndx < ehdr.e_shnum) + name = sec_strtab + secs[shndx].shdr.sh_name; + else if (shndx == SHN_ABS) + name = "ABSOLUTE"; + else if (shndx == SHN_COMMON) + name = "COMMON"; + else + name = "<noname>"; + return name; +} + +static struct section *sec_lookup(const char *secname) +{ + int i; + + for (i = 0; i < ehdr.e_shnum; i++) + if (strcmp(secname, sec_name(i)) == 0) + return &secs[i]; + + return NULL; +} + +static const char *sym_name(const char *sym_strtab, Elf_Sym *sym) +{ + const char *name; + + if (sym->st_name) + name = sym_strtab + sym->st_name; + else + name = sec_name(sym->st_shndx); + return name; +} + +#if BYTE_ORDER == LITTLE_ENDIAN +#define le16_to_cpu(val) (val) +#define le32_to_cpu(val) (val) +#define le64_to_cpu(val) (val) +#define be16_to_cpu(val) bswap_16(val) +#define be32_to_cpu(val) bswap_32(val) +#define be64_to_cpu(val) bswap_64(val) + +#define cpu_to_le16(val) (val) +#define cpu_to_le32(val) (val) +#define cpu_to_le64(val) (val) +#define cpu_to_be16(val) bswap_16(val) +#define cpu_to_be32(val) bswap_32(val) +#define cpu_to_be64(val) bswap_64(val) +#endif +#if BYTE_ORDER == BIG_ENDIAN +#define le16_to_cpu(val) bswap_16(val) +#define le32_to_cpu(val) bswap_32(val) +#define le64_to_cpu(val) bswap_64(val) +#define be16_to_cpu(val) (val) +#define be32_to_cpu(val) (val) +#define be64_to_cpu(val) (val) + +#define cpu_to_le16(val) bswap_16(val) +#define cpu_to_le32(val) bswap_32(val) +#define cpu_to_le64(val) bswap_64(val) +#define cpu_to_be16(val) (val) +#define cpu_to_be32(val) (val) +#define cpu_to_be64(val) (val) +#endif + +static uint16_t elf16_to_cpu(uint16_t val) +{ + if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB) + return le16_to_cpu(val); + else + return be16_to_cpu(val); +} + +static uint32_t elf32_to_cpu(uint32_t val) +{ + if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB) + return le32_to_cpu(val); + else + return be32_to_cpu(val); +} + +static uint32_t cpu_to_elf32(uint32_t val) +{ + if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB) + return cpu_to_le32(val); + else + return cpu_to_be32(val); +} + +#define elf_half_to_cpu(x) elf16_to_cpu(x) +#define elf_word_to_cpu(x) elf32_to_cpu(x) + +#if ELF_BITS == 64 +static uint64_t elf64_to_cpu(uint64_t val) +{ + if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB) + return le64_to_cpu(val); + else + return be64_to_cpu(val); +} +#define elf_addr_to_cpu(x) elf64_to_cpu(x) +#define elf_off_to_cpu(x) elf64_to_cpu(x) +#define elf_xword_to_cpu(x) elf64_to_cpu(x) +#else +#define elf_addr_to_cpu(x) elf32_to_cpu(x) +#define elf_off_to_cpu(x) elf32_to_cpu(x) +#define elf_xword_to_cpu(x) elf32_to_cpu(x) +#endif + +static void read_ehdr(FILE *fp) +{ + if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) + die("Cannot read ELF header: %s\n", strerror(errno)); + + if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) + die("No ELF magic\n"); + + if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) + die("Not a %d bit executable\n", ELF_BITS); + + if ((ehdr.e_ident[EI_DATA] != ELFDATA2LSB) && + (ehdr.e_ident[EI_DATA] != ELFDATA2MSB)) + die("Unknown ELF Endianness\n"); + + if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) + die("Unknown ELF version\n"); + + /* Convert the fields to native endian */ + ehdr.e_type = elf_half_to_cpu(ehdr.e_type); + ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine); + ehdr.e_version = elf_word_to_cpu(ehdr.e_version); + ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry); + ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff); + ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff); + ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags); + ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize); + ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize); + ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum); + ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize); + ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum); + ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx); + + if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) + die("Unsupported ELF header type\n"); + + if (ehdr.e_machine != ELF_MACHINE) + die("Not for %s\n", ELF_MACHINE_NAME); + + if (ehdr.e_version != EV_CURRENT) + die("Unknown ELF version\n"); + + if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) + die("Bad Elf header size\n"); + + if (ehdr.e_phentsize != sizeof(Elf_Phdr)) + die("Bad program header entry\n"); + + if (ehdr.e_shentsize != sizeof(Elf_Shdr)) + die("Bad section header entry\n"); + + if (ehdr.e_shstrndx >= ehdr.e_shnum) + die("String table index out of bounds\n"); +} + +static void read_shdrs(FILE *fp) +{ + int i; + Elf_Shdr shdr; + + secs = calloc(ehdr.e_shnum, sizeof(struct section)); + if (!secs) + die("Unable to allocate %d section headers\n", ehdr.e_shnum); + + if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) + die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno)); + + for (i = 0; i < ehdr.e_shnum; i++) { + struct section *sec = &secs[i]; + + sec->shdr_offset = ftell(fp); + if (fread(&shdr, sizeof(shdr), 1, fp) != 1) + die("Cannot read ELF section headers %d/%d: %s\n", + i, ehdr.e_shnum, strerror(errno)); + sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name); + sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type); + sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags); + sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr); + sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset); + sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size); + sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link); + sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info); + sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign); + sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize); + if (sec->shdr.sh_link < ehdr.e_shnum) + sec->link = &secs[sec->shdr.sh_link]; + } +} + +static void read_strtabs(FILE *fp) +{ + int i; + + for (i = 0; i < ehdr.e_shnum; i++) { + struct section *sec = &secs[i]; + + if (sec->shdr.sh_type != SHT_STRTAB) + continue; + + sec->strtab = malloc(sec->shdr.sh_size); + if (!sec->strtab) + die("malloc of %d bytes for strtab failed\n", + sec->shdr.sh_size); + + if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) + die("Seek to %d failed: %s\n", + sec->shdr.sh_offset, strerror(errno)); + + if (fread(sec->strtab, 1, sec->shdr.sh_size, fp) != + sec->shdr.sh_size) + die("Cannot read symbol table: %s\n", strerror(errno)); + } +} + +static void read_symtabs(FILE *fp) +{ + int i, j; + + for (i = 0; i < ehdr.e_shnum; i++) { + struct section *sec = &secs[i]; + if (sec->shdr.sh_type != SHT_SYMTAB) + continue; + + sec->symtab = malloc(sec->shdr.sh_size); + if (!sec->symtab) + die("malloc of %d bytes for symtab failed\n", + sec->shdr.sh_size); + + if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) + die("Seek to %d failed: %s\n", + sec->shdr.sh_offset, strerror(errno)); + + if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) != + sec->shdr.sh_size) + die("Cannot read symbol table: %s\n", strerror(errno)); + + for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) { + Elf_Sym *sym = &sec->symtab[j]; + + sym->st_name = elf_word_to_cpu(sym->st_name); + sym->st_value = elf_addr_to_cpu(sym->st_value); + sym->st_size = elf_xword_to_cpu(sym->st_size); + sym->st_shndx = elf_half_to_cpu(sym->st_shndx); + } + } +} + +static void read_relocs(FILE *fp) +{ + static unsigned long base = 0; + int i, j; + + if (!base) { + struct section *sec = sec_lookup(".text"); + + if (!sec) + die("Could not find .text section\n"); + + base = sec->shdr.sh_addr; + } + + for (i = 0; i < ehdr.e_shnum; i++) { + struct section *sec = &secs[i]; + + if (sec->shdr.sh_type != SHT_REL_TYPE) + continue; + + sec->reltab = malloc(sec->shdr.sh_size); + if (!sec->reltab) + die("malloc of %d bytes for relocs failed\n", + sec->shdr.sh_size); + + if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) + die("Seek to %d failed: %s\n", + sec->shdr.sh_offset, strerror(errno)); + + if (fread(sec->reltab, 1, sec->shdr.sh_size, fp) != + sec->shdr.sh_size) + die("Cannot read symbol table: %s\n", strerror(errno)); + + for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) { + Elf_Rel *rel = &sec->reltab[j]; + + rel->r_offset = elf_addr_to_cpu(rel->r_offset); + /* Set offset into kernel image */ + rel->r_offset -= base; +#if (ELF_BITS == 32) + rel->r_info = elf_xword_to_cpu(rel->r_info); +#else + /* Convert MIPS64 RELA format - only the symbol + * index needs converting to native endianness + */ + rel->r_info = rel->r_info; + ELF_R_SYM(rel->r_info) = elf32_to_cpu(ELF_R_SYM(rel->r_info)); +#endif +#if (SHT_REL_TYPE == SHT_RELA) + rel->r_addend = elf_xword_to_cpu(rel->r_addend); +#endif + } + } +} + +static void remove_relocs(FILE *fp) +{ + int i; + Elf_Shdr shdr; + + for (i = 0; i < ehdr.e_shnum; i++) { + struct section *sec = &secs[i]; + + if (sec->shdr.sh_type != SHT_REL_TYPE) + continue; + + if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0) + die("Seek to %d failed: %s\n", + sec->shdr_offset, strerror(errno)); + + if (fread(&shdr, sizeof(shdr), 1, fp) != 1) + die("Cannot read ELF section headers %d/%d: %s\n", + i, ehdr.e_shnum, strerror(errno)); + + /* Set relocation section size to 0, effectively removing it. + * This is necessary due to lack of support for relocations + * in objcopy when creating 32bit elf from 64bit elf. + */ + shdr.sh_size = 0; + + if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0) + die("Seek to %d failed: %s\n", + sec->shdr_offset, strerror(errno)); + + if (fwrite(&shdr, sizeof(shdr), 1, fp) != 1) + die("Cannot write ELF section headers %d/%d: %s\n", + i, ehdr.e_shnum, strerror(errno)); + } +} + +static void add_reloc(struct relocs *r, uint32_t offset, unsigned type) +{ + /* Relocation representation in binary table: + * |76543210|76543210|76543210|76543210| + * | Type | offset from _text >> 2 | + */ + offset >>= 2; + if (offset > 0x00FFFFFF) + die("Kernel image exceeds maximum size for relocation!\n"); + + offset = (offset & 0x00FFFFFF) | ((type & 0xFF) << 24); + + if (r->count == r->size) { + unsigned long newsize = r->size + 50000; + void *mem = realloc(r->offset, newsize * sizeof(r->offset[0])); + + if (!mem) + die("realloc failed\n"); + + r->offset = mem; + r->size = newsize; + } + r->offset[r->count++] = offset; +} + +static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel, + Elf_Sym *sym, const char *symname)) +{ + int i; + + /* Walk through the relocations */ + for (i = 0; i < ehdr.e_shnum; i++) { + char *sym_strtab; + Elf_Sym *sh_symtab; + struct section *sec_applies, *sec_symtab; + int j; + struct section *sec = &secs[i]; + + if (sec->shdr.sh_type != SHT_REL_TYPE) + continue; + + sec_symtab = sec->link; + sec_applies = &secs[sec->shdr.sh_info]; + if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) + continue; + + sh_symtab = sec_symtab->symtab; + sym_strtab = sec_symtab->link->strtab; + for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) { + Elf_Rel *rel = &sec->reltab[j]; + Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)]; + const char *symname = sym_name(sym_strtab, sym); + + process(sec, rel, sym, symname); + } + } +} + +static int do_reloc(struct section *sec, Elf_Rel *rel, Elf_Sym *sym, + const char *symname) +{ + unsigned r_type = ELF_R_TYPE(rel->r_info); + unsigned bind = ELF_ST_BIND(sym->st_info); + + if ((bind == STB_WEAK) && (sym->st_value == 0)) { + /* Don't relocate weak symbols without a target */ + return 0; + } + + if (regex_skip_reloc(symname)) + return 0; + + switch (r_type) { + case R_MIPS_NONE: + case R_MIPS_REL32: + case R_MIPS_PC16: + case R_MIPS_PC21_S2: + case R_MIPS_PC26_S2: + /* + * NONE can be ignored and PC relative relocations don't + * need to be adjusted. + */ + case R_MIPS_HIGHEST: + case R_MIPS_HIGHER: + /* We support relocating within the same 4Gb segment only, + * thus leaving the top 32bits unchanged + */ + case R_MIPS_LO16: + /* We support relocating by 64k jumps only + * thus leaving the bottom 16bits unchanged + */ + break; + + case R_MIPS_64: + case R_MIPS_32: + case R_MIPS_26: + case R_MIPS_HI16: + add_reloc(&relocs, rel->r_offset, r_type); + break; + + default: + die("Unsupported relocation type: %s (%d)\n", + rel_type(r_type), r_type); + break; + } + + return 0; +} + +static int write_reloc_as_bin(uint32_t v, FILE *f) +{ + unsigned char buf[4]; + + v = cpu_to_elf32(v); + + memcpy(buf, &v, sizeof(uint32_t)); + return fwrite(buf, 1, 4, f); +} + +static int write_reloc_as_text(uint32_t v, FILE *f) +{ + int res; + + res = fprintf(f, "\t.long 0x%08"PRIx32"\n", v); + if (res < 0) + return res; + else + return sizeof(uint32_t); +} + +static void emit_relocs(int as_text, int as_bin, FILE *outf) +{ + int i; + int (*write_reloc)(uint32_t, FILE *) = write_reloc_as_bin; + int size = 0; + int size_reserved; + struct section *sec_reloc; + + sec_reloc = sec_lookup(".data.reloc"); + if (!sec_reloc) + die("Could not find relocation section\n"); + + size_reserved = sec_reloc->shdr.sh_size; + + /* Collect up the relocations */ + walk_relocs(do_reloc); + + /* Print the relocations */ + if (as_text) { + /* Print the relocations in a form suitable that + * gas will like. + */ + printf(".section \".data.reloc\",\"a\"\n"); + printf(".balign 4\n"); + /* Output text to stdout */ + write_reloc = write_reloc_as_text; + outf = stdout; + } else if (as_bin) { + /* Output raw binary to stdout */ + outf = stdout; + } else { + /* Seek to offset of the relocation section. + * Each relocation is then written into the + * vmlinux kernel image. + */ + if (fseek(outf, sec_reloc->shdr.sh_offset, SEEK_SET) < 0) { + die("Seek to %d failed: %s\n", + sec_reloc->shdr.sh_offset, strerror(errno)); + } + } + + for (i = 0; i < relocs.count; i++) + size += write_reloc(relocs.offset[i], outf); + + /* Print a stop, but only if we've actually written some relocs */ + if (size) + size += write_reloc(0, outf); + + if (size > size_reserved) + /* Die, but suggest a value for CONFIG_RELOCATION_TABLE_SIZE + * which will fix this problem and allow a bit of headroom + * if more kernel features are enabled + */ + die("Relocations overflow available space!\n" \ + "Please adjust CONFIG_RELOCATION_TABLE_SIZE " \ + "to at least 0x%08x\n", (size + 0x1000) & ~0xFFF); +} + +/* + * As an aid to debugging problems with different linkers + * print summary information about the relocs. + * Since different linkers tend to emit the sections in + * different orders we use the section names in the output. + */ +static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, + const char *symname) +{ + printf("%16s 0x%08x %16s %40s %16s\n", + sec_name(sec->shdr.sh_info), + (unsigned int)rel->r_offset, + rel_type(ELF_R_TYPE(rel->r_info)), + symname, + sec_name(sym->st_shndx)); + return 0; +} + +static void print_reloc_info(void) +{ + printf("%16s %10s %16s %40s %16s\n", + "reloc section", + "offset", + "reloc type", + "symbol", + "symbol section"); + walk_relocs(do_reloc_info); +} + +#if ELF_BITS == 64 +# define process process_64 +#else +# define process process_32 +#endif + +void process(FILE *fp, int as_text, int as_bin, + int show_reloc_info, int keep_relocs) +{ + regex_init(); + read_ehdr(fp); + read_shdrs(fp); + read_strtabs(fp); + read_symtabs(fp); + read_relocs(fp); + if (show_reloc_info) { + print_reloc_info(); + return; + } + emit_relocs(as_text, as_bin, fp); + if (!keep_relocs) + remove_relocs(fp); +} |