| // SPDX-License-Identifier: GPL-2.0 |
| #include "relocs.h" |
| |
| #define ELF_BITS 64 |
| |
| #define ELF_MACHINE EM_SW64 |
| #define ELF_MACHINE_NAME "SW64" |
| #define SHT_REL_TYPE SHT_RELA |
| #define Elf_Rel Elf64_Rela |
| |
| #define ELF_CLASS ELFCLASS64 |
| #define ELF_R_SYM(val) ELF64_R_SYM(val) |
| #define ELF_R_TYPE(val) ELF64_R_TYPE(val) |
| #define ELF_ST_TYPE(o) ELF64_ST_TYPE(o) |
| #define ELF_ST_BIND(o) ELF64_ST_BIND(o) |
| #define ELF_ST_VISIBILITY(o) ELF64_ST_VISIBILITY(o) |
| |
| #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 int type) |
| { |
| static const char * const type_name[] = { |
| #define REL_TYPE(X)[X] = #X |
| REL_TYPE(R_SW64_NONE), |
| REL_TYPE(R_SW64_REFQUAD), |
| REL_TYPE(R_SW64_LITERAL), |
| REL_TYPE(R_SW64_LITUSE), |
| REL_TYPE(R_SW64_GPDISP), |
| REL_TYPE(R_SW64_BRADDR), |
| REL_TYPE(R_SW64_HINT), |
| REL_TYPE(R_SW64_SREL32), |
| REL_TYPE(R_SW64_GPRELHIGH), |
| REL_TYPE(R_SW64_GPRELLOW), |
| #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 int 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; |
| } |
| |
| #define le16_to_cpu(val) (val) |
| #define le32_to_cpu(val) (val) |
| #define le64_to_cpu(val) (val) |
| |
| #define cpu_to_le16(val) (val) |
| #define cpu_to_le32(val) (val) |
| #define cpu_to_le64(val) (val) |
| |
| static uint16_t elf16_to_cpu(uint16_t val) |
| { |
| return le16_to_cpu(val); |
| } |
| |
| static uint32_t elf32_to_cpu(uint32_t val) |
| { |
| return le32_to_cpu(val); |
| } |
| |
| static uint32_t cpu_to_elf32(uint32_t val) |
| { |
| return cpu_to_le32(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) |
| { |
| return le64_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; |
| 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; |
| /* Convert SW64 RELA format - only the symbol |
| * index needs converting to native endianness |
| */ |
| rel->r_info = elf_xword_to_cpu(rel->r_info); |
| #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 int 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 int r_type = ELF_R_TYPE(rel->r_info); |
| unsigned int 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_SW64_NONE: |
| case R_SW64_LITERAL: /* relocated by GOT */ |
| case R_SW64_LITUSE: |
| case R_SW64_GPDISP: |
| case R_SW64_BRADDR: |
| case R_SW64_HINT: |
| case R_SW64_SREL32: |
| case R_SW64_GPRELHIGH: |
| case R_SW64_GPRELLOW: |
| case R_SW64_LITERAL_GOT: |
| /* |
| * NONE can be ignored and PC relative relocations don't |
| * need to be adjusted. |
| */ |
| break; |
| |
| case R_SW64_REFQUAD: |
| 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 8\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%x %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); |
| } |
| |
| 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); |
| } |