| // SPDX-License-Identifier: GPL-2.0 |
| /* 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; |
| static unsigned long shnum; |
| static unsigned int shstrndx; |
| |
| struct relocs { |
| uint32_t *offset; |
| unsigned long count; |
| unsigned long size; |
| }; |
| |
| static struct relocs relocs16; |
| static struct relocs relocs32; |
| #if ELF_BITS == 64 |
| static struct relocs relocs32neg; |
| static struct relocs relocs64; |
| #endif |
| |
| struct section { |
| Elf_Shdr shdr; |
| struct section *link; |
| Elf_Sym *symtab; |
| Elf_Rel *reltab; |
| char *strtab; |
| }; |
| static struct section *secs; |
| |
| static const char * const sym_regex_kernel[S_NSYMTYPES] = { |
| /* |
| * Following symbols have been audited. There values are constant and do |
| * not change if bzImage is loaded at a different physical address than |
| * the address for which it has been compiled. Don't warn user about |
| * absolute relocations present w.r.t these symbols. |
| */ |
| [S_ABS] = |
| "^(xen_irq_disable_direct_reloc$|" |
| "xen_save_fl_direct_reloc$|" |
| "VDSO|" |
| "__crc_)", |
| |
| /* |
| * These symbols are known to be relative, even if the linker marks them |
| * as absolute (typically defined outside any section in the linker script.) |
| */ |
| [S_REL] = |
| "^(__init_(begin|end)|" |
| "__x86_cpu_dev_(start|end)|" |
| "(__parainstructions|__alt_instructions)(|_end)|" |
| "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|" |
| "__(start|end)_pci_.*|" |
| "__(start|end)_builtin_fw|" |
| "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|" |
| "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|" |
| "__(start|stop)___param|" |
| "__(start|stop)___modver|" |
| "__(start|stop)___bug_table|" |
| "__tracedata_(start|end)|" |
| "__(start|stop)_notes|" |
| "__end_rodata|" |
| "__end_rodata_aligned|" |
| "__initramfs_start|" |
| "(jiffies|jiffies_64)|" |
| #if ELF_BITS == 64 |
| "__per_cpu_load|" |
| "init_per_cpu__.*|" |
| "__end_rodata_hpage_align|" |
| #endif |
| "__vvar_page|" |
| "_end)$" |
| }; |
| |
| |
| static const char * const sym_regex_realmode[S_NSYMTYPES] = { |
| /* |
| * These symbols are known to be relative, even if the linker marks them |
| * as absolute (typically defined outside any section in the linker script.) |
| */ |
| [S_REL] = |
| "^pa_", |
| |
| /* |
| * These are 16-bit segment symbols when compiling 16-bit code. |
| */ |
| [S_SEG] = |
| "^real_mode_seg$", |
| |
| /* |
| * These are offsets belonging to segments, as opposed to linear addresses, |
| * when compiling 16-bit code. |
| */ |
| [S_LIN] = |
| "^pa_", |
| }; |
| |
| static const char * const *sym_regex; |
| |
| static regex_t sym_regex_c[S_NSYMTYPES]; |
| static int is_reloc(enum symtype type, const char *sym_name) |
| { |
| return sym_regex[type] && |
| !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0); |
| } |
| |
| static void regex_init(int use_real_mode) |
| { |
| char errbuf[128]; |
| int err; |
| int i; |
| |
| if (use_real_mode) |
| sym_regex = sym_regex_realmode; |
| else |
| sym_regex = sym_regex_kernel; |
| |
| for (i = 0; i < S_NSYMTYPES; i++) { |
| if (!sym_regex[i]) |
| continue; |
| |
| err = regcomp(&sym_regex_c[i], sym_regex[i], |
| REG_EXTENDED|REG_NOSUB); |
| |
| if (err) { |
| regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf)); |
| die("%s", errbuf); |
| } |
| } |
| } |
| |
| static const char *sym_type(unsigned type) |
| { |
| static const char *type_name[] = { |
| #define SYM_TYPE(X) [X] = #X |
| SYM_TYPE(STT_NOTYPE), |
| SYM_TYPE(STT_OBJECT), |
| SYM_TYPE(STT_FUNC), |
| SYM_TYPE(STT_SECTION), |
| SYM_TYPE(STT_FILE), |
| SYM_TYPE(STT_COMMON), |
| SYM_TYPE(STT_TLS), |
| #undef SYM_TYPE |
| }; |
| const char *name = "unknown sym type name"; |
| if (type < ARRAY_SIZE(type_name)) { |
| name = type_name[type]; |
| } |
| return name; |
| } |
| |
| static const char *sym_bind(unsigned bind) |
| { |
| static const char *bind_name[] = { |
| #define SYM_BIND(X) [X] = #X |
| SYM_BIND(STB_LOCAL), |
| SYM_BIND(STB_GLOBAL), |
| SYM_BIND(STB_WEAK), |
| #undef SYM_BIND |
| }; |
| const char *name = "unknown sym bind name"; |
| if (bind < ARRAY_SIZE(bind_name)) { |
| name = bind_name[bind]; |
| } |
| return name; |
| } |
| |
| static const char *sym_visibility(unsigned visibility) |
| { |
| static const char *visibility_name[] = { |
| #define SYM_VISIBILITY(X) [X] = #X |
| SYM_VISIBILITY(STV_DEFAULT), |
| SYM_VISIBILITY(STV_INTERNAL), |
| SYM_VISIBILITY(STV_HIDDEN), |
| SYM_VISIBILITY(STV_PROTECTED), |
| #undef SYM_VISIBILITY |
| }; |
| const char *name = "unknown sym visibility name"; |
| if (visibility < ARRAY_SIZE(visibility_name)) { |
| name = visibility_name[visibility]; |
| } |
| return name; |
| } |
| |
| static const char *rel_type(unsigned type) |
| { |
| static const char *type_name[] = { |
| #define REL_TYPE(X) [X] = #X |
| #if ELF_BITS == 64 |
| REL_TYPE(R_X86_64_NONE), |
| REL_TYPE(R_X86_64_64), |
| REL_TYPE(R_X86_64_PC64), |
| REL_TYPE(R_X86_64_PC32), |
| REL_TYPE(R_X86_64_GOT32), |
| REL_TYPE(R_X86_64_PLT32), |
| REL_TYPE(R_X86_64_COPY), |
| REL_TYPE(R_X86_64_GLOB_DAT), |
| REL_TYPE(R_X86_64_JUMP_SLOT), |
| REL_TYPE(R_X86_64_RELATIVE), |
| REL_TYPE(R_X86_64_GOTPCREL), |
| REL_TYPE(R_X86_64_32), |
| REL_TYPE(R_X86_64_32S), |
| REL_TYPE(R_X86_64_16), |
| REL_TYPE(R_X86_64_PC16), |
| REL_TYPE(R_X86_64_8), |
| REL_TYPE(R_X86_64_PC8), |
| #else |
| REL_TYPE(R_386_NONE), |
| REL_TYPE(R_386_32), |
| REL_TYPE(R_386_PC32), |
| REL_TYPE(R_386_GOT32), |
| REL_TYPE(R_386_PLT32), |
| REL_TYPE(R_386_COPY), |
| REL_TYPE(R_386_GLOB_DAT), |
| REL_TYPE(R_386_JMP_SLOT), |
| REL_TYPE(R_386_RELATIVE), |
| REL_TYPE(R_386_GOTOFF), |
| REL_TYPE(R_386_GOTPC), |
| REL_TYPE(R_386_8), |
| REL_TYPE(R_386_PC8), |
| REL_TYPE(R_386_16), |
| REL_TYPE(R_386_PC16), |
| #endif |
| #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[shstrndx].strtab; |
| name = "<noname>"; |
| if (shndx < shnum) { |
| name = sec_strtab + secs[shndx].shdr.sh_name; |
| } |
| else if (shndx == SHN_ABS) { |
| name = "ABSOLUTE"; |
| } |
| else if (shndx == SHN_COMMON) { |
| name = "COMMON"; |
| } |
| return name; |
| } |
| |
| static const char *sym_name(const char *sym_strtab, Elf_Sym *sym) |
| { |
| const char *name; |
| name = "<noname>"; |
| if (sym->st_name) { |
| name = sym_strtab + sym->st_name; |
| } |
| else { |
| name = sec_name(sym->st_shndx); |
| } |
| return name; |
| } |
| |
| static Elf_Sym *sym_lookup(const char *symname) |
| { |
| int i; |
| for (i = 0; i < shnum; i++) { |
| struct section *sec = &secs[i]; |
| long nsyms; |
| char *strtab; |
| Elf_Sym *symtab; |
| Elf_Sym *sym; |
| |
| if (sec->shdr.sh_type != SHT_SYMTAB) |
| continue; |
| |
| nsyms = sec->shdr.sh_size/sizeof(Elf_Sym); |
| symtab = sec->symtab; |
| strtab = sec->link->strtab; |
| |
| for (sym = symtab; --nsyms >= 0; sym++) { |
| if (!sym->st_name) |
| continue; |
| if (strcmp(symname, strtab + sym->st_name) == 0) |
| return sym; |
| } |
| } |
| return 0; |
| } |
| |
| #if BYTE_ORDER == LITTLE_ENDIAN |
| #define le16_to_cpu(val) (val) |
| #define le32_to_cpu(val) (val) |
| #define le64_to_cpu(val) (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) |
| #endif |
| |
| 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); |
| } |
| |
| #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) { |
| die("Not a LSB ELF executable\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); |
| |
| shnum = ehdr.e_shnum; |
| shstrndx = 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 (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) { |
| Elf_Shdr shdr; |
| |
| if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) |
| die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno)); |
| |
| if (fread(&shdr, sizeof(shdr), 1, fp) != 1) |
| die("Cannot read initial ELF section header: %s\n", strerror(errno)); |
| |
| if (shnum == SHN_UNDEF) |
| shnum = elf_xword_to_cpu(shdr.sh_size); |
| |
| if (shstrndx == SHN_XINDEX) |
| shstrndx = elf_word_to_cpu(shdr.sh_link); |
| } |
| |
| if (shstrndx >= shnum) |
| die("String table index out of bounds\n"); |
| } |
| |
| static void read_shdrs(FILE *fp) |
| { |
| int i; |
| Elf_Shdr shdr; |
| |
| secs = calloc(shnum, sizeof(struct section)); |
| if (!secs) { |
| die("Unable to allocate %d section headers\n", |
| 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 < shnum; i++) { |
| struct section *sec = &secs[i]; |
| if (fread(&shdr, sizeof(shdr), 1, fp) != 1) |
| die("Cannot read ELF section headers %d/%d: %s\n", |
| i, 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 < shnum) |
| sec->link = &secs[sec->shdr.sh_link]; |
| } |
| |
| } |
| |
| static void read_strtabs(FILE *fp) |
| { |
| int i; |
| for (i = 0; i < 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 < 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) |
| { |
| int i,j; |
| for (i = 0; i < 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); |
| 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 print_absolute_symbols(void) |
| { |
| int i; |
| const char *format; |
| |
| if (ELF_BITS == 64) |
| format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n"; |
| else |
| format = "%5d %08"PRIx32" %5"PRId32" %10s %10s %12s %s\n"; |
| |
| printf("Absolute symbols\n"); |
| printf(" Num: Value Size Type Bind Visibility Name\n"); |
| for (i = 0; i < shnum; i++) { |
| struct section *sec = &secs[i]; |
| char *sym_strtab; |
| int j; |
| |
| if (sec->shdr.sh_type != SHT_SYMTAB) { |
| continue; |
| } |
| sym_strtab = sec->link->strtab; |
| for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) { |
| Elf_Sym *sym; |
| const char *name; |
| sym = &sec->symtab[j]; |
| name = sym_name(sym_strtab, sym); |
| if (sym->st_shndx != SHN_ABS) { |
| continue; |
| } |
| printf(format, |
| j, sym->st_value, sym->st_size, |
| sym_type(ELF_ST_TYPE(sym->st_info)), |
| sym_bind(ELF_ST_BIND(sym->st_info)), |
| sym_visibility(ELF_ST_VISIBILITY(sym->st_other)), |
| name); |
| } |
| } |
| printf("\n"); |
| } |
| |
| static void print_absolute_relocs(void) |
| { |
| int i, printed = 0; |
| const char *format; |
| |
| if (ELF_BITS == 64) |
| format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64" %s\n"; |
| else |
| format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n"; |
| |
| for (i = 0; i < shnum; i++) { |
| struct section *sec = &secs[i]; |
| struct section *sec_applies, *sec_symtab; |
| char *sym_strtab; |
| Elf_Sym *sh_symtab; |
| int j; |
| 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; |
| Elf_Sym *sym; |
| const char *name; |
| rel = &sec->reltab[j]; |
| sym = &sh_symtab[ELF_R_SYM(rel->r_info)]; |
| name = sym_name(sym_strtab, sym); |
| if (sym->st_shndx != SHN_ABS) { |
| continue; |
| } |
| |
| /* Absolute symbols are not relocated if bzImage is |
| * loaded at a non-compiled address. Display a warning |
| * to user at compile time about the absolute |
| * relocations present. |
| * |
| * User need to audit the code to make sure |
| * some symbols which should have been section |
| * relative have not become absolute because of some |
| * linker optimization or wrong programming usage. |
| * |
| * Before warning check if this absolute symbol |
| * relocation is harmless. |
| */ |
| if (is_reloc(S_ABS, name) || is_reloc(S_REL, name)) |
| continue; |
| |
| if (!printed) { |
| printf("WARNING: Absolute relocations" |
| " present\n"); |
| printf("Offset Info Type Sym.Value " |
| "Sym.Name\n"); |
| printed = 1; |
| } |
| |
| printf(format, |
| rel->r_offset, |
| rel->r_info, |
| rel_type(ELF_R_TYPE(rel->r_info)), |
| sym->st_value, |
| name); |
| } |
| } |
| |
| if (printed) |
| printf("\n"); |
| } |
| |
| static void add_reloc(struct relocs *r, uint32_t offset) |
| { |
| 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 of %ld entries for relocs failed\n", |
| newsize); |
| 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 < 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); |
| } |
| } |
| } |
| |
| /* |
| * The .data..percpu section is a special case for x86_64 SMP kernels. |
| * It is used to initialize the actual per_cpu areas and to provide |
| * definitions for the per_cpu variables that correspond to their offsets |
| * within the percpu area. Since the values of all of the symbols need |
| * to be offsets from the start of the per_cpu area the virtual address |
| * (sh_addr) of .data..percpu is 0 in SMP kernels. |
| * |
| * This means that: |
| * |
| * Relocations that reference symbols in the per_cpu area do not |
| * need further relocation (since the value is an offset relative |
| * to the start of the per_cpu area that does not change). |
| * |
| * Relocations that apply to the per_cpu area need to have their |
| * offset adjusted by by the value of __per_cpu_load to make them |
| * point to the correct place in the loaded image (because the |
| * virtual address of .data..percpu is 0). |
| * |
| * For non SMP kernels .data..percpu is linked as part of the normal |
| * kernel data and does not require special treatment. |
| * |
| */ |
| static int per_cpu_shndx = -1; |
| static Elf_Addr per_cpu_load_addr; |
| |
| static void percpu_init(void) |
| { |
| int i; |
| for (i = 0; i < shnum; i++) { |
| ElfW(Sym) *sym; |
| if (strcmp(sec_name(i), ".data..percpu")) |
| continue; |
| |
| if (secs[i].shdr.sh_addr != 0) /* non SMP kernel */ |
| return; |
| |
| sym = sym_lookup("__per_cpu_load"); |
| if (!sym) |
| die("can't find __per_cpu_load\n"); |
| |
| per_cpu_shndx = i; |
| per_cpu_load_addr = sym->st_value; |
| return; |
| } |
| } |
| |
| #if ELF_BITS == 64 |
| |
| /* |
| * Check to see if a symbol lies in the .data..percpu section. |
| * |
| * The linker incorrectly associates some symbols with the |
| * .data..percpu section so we also need to check the symbol |
| * name to make sure that we classify the symbol correctly. |
| * |
| * The GNU linker incorrectly associates: |
| * __init_begin |
| * __per_cpu_load |
| * |
| * The "gold" linker incorrectly associates: |
| * init_per_cpu__fixed_percpu_data |
| * init_per_cpu__gdt_page |
| */ |
| static int is_percpu_sym(ElfW(Sym) *sym, const char *symname) |
| { |
| return (sym->st_shndx == per_cpu_shndx) && |
| strcmp(symname, "__init_begin") && |
| strcmp(symname, "__per_cpu_load") && |
| strncmp(symname, "init_per_cpu_", 13); |
| } |
| |
| |
| static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, |
| const char *symname) |
| { |
| unsigned r_type = ELF64_R_TYPE(rel->r_info); |
| ElfW(Addr) offset = rel->r_offset; |
| int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname); |
| |
| if (sym->st_shndx == SHN_UNDEF) |
| return 0; |
| |
| /* |
| * Adjust the offset if this reloc applies to the percpu section. |
| */ |
| if (sec->shdr.sh_info == per_cpu_shndx) |
| offset += per_cpu_load_addr; |
| |
| switch (r_type) { |
| case R_X86_64_NONE: |
| /* NONE can be ignored. */ |
| break; |
| |
| case R_X86_64_PC32: |
| case R_X86_64_PLT32: |
| /* |
| * PC relative relocations don't need to be adjusted unless |
| * referencing a percpu symbol. |
| * |
| * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32. |
| */ |
| if (is_percpu_sym(sym, symname)) |
| add_reloc(&relocs32neg, offset); |
| break; |
| |
| case R_X86_64_PC64: |
| /* |
| * Only used by jump labels |
| */ |
| if (is_percpu_sym(sym, symname)) |
| die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n", |
| symname); |
| break; |
| |
| case R_X86_64_32: |
| case R_X86_64_32S: |
| case R_X86_64_64: |
| /* |
| * References to the percpu area don't need to be adjusted. |
| */ |
| if (is_percpu_sym(sym, symname)) |
| break; |
| |
| if (shn_abs) { |
| /* |
| * Whitelisted absolute symbols do not require |
| * relocation. |
| */ |
| if (is_reloc(S_ABS, symname)) |
| break; |
| |
| die("Invalid absolute %s relocation: %s\n", |
| rel_type(r_type), symname); |
| break; |
| } |
| |
| /* |
| * Relocation offsets for 64 bit kernels are output |
| * as 32 bits and sign extended back to 64 bits when |
| * the relocations are processed. |
| * Make sure that the offset will fit. |
| */ |
| if ((int32_t)offset != (int64_t)offset) |
| die("Relocation offset doesn't fit in 32 bits\n"); |
| |
| if (r_type == R_X86_64_64) |
| add_reloc(&relocs64, offset); |
| else |
| add_reloc(&relocs32, offset); |
| break; |
| |
| default: |
| die("Unsupported relocation type: %s (%d)\n", |
| rel_type(r_type), r_type); |
| break; |
| } |
| |
| return 0; |
| } |
| |
| #else |
| |
| static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym, |
| const char *symname) |
| { |
| unsigned r_type = ELF32_R_TYPE(rel->r_info); |
| int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname); |
| |
| switch (r_type) { |
| case R_386_NONE: |
| case R_386_PC32: |
| case R_386_PC16: |
| case R_386_PC8: |
| case R_386_PLT32: |
| /* |
| * NONE can be ignored and PC relative relocations don't need |
| * to be adjusted. Because sym must be defined, R_386_PLT32 can |
| * be treated the same way as R_386_PC32. |
| */ |
| break; |
| |
| case R_386_32: |
| if (shn_abs) { |
| /* |
| * Whitelisted absolute symbols do not require |
| * relocation. |
| */ |
| if (is_reloc(S_ABS, symname)) |
| break; |
| |
| die("Invalid absolute %s relocation: %s\n", |
| rel_type(r_type), symname); |
| break; |
| } |
| |
| add_reloc(&relocs32, rel->r_offset); |
| break; |
| |
| default: |
| die("Unsupported relocation type: %s (%d)\n", |
| rel_type(r_type), r_type); |
| break; |
| } |
| |
| return 0; |
| } |
| |
| static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym, |
| const char *symname) |
| { |
| unsigned r_type = ELF32_R_TYPE(rel->r_info); |
| int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname); |
| |
| switch (r_type) { |
| case R_386_NONE: |
| case R_386_PC32: |
| case R_386_PC16: |
| case R_386_PC8: |
| case R_386_PLT32: |
| /* |
| * NONE can be ignored and PC relative relocations don't need |
| * to be adjusted. Because sym must be defined, R_386_PLT32 can |
| * be treated the same way as R_386_PC32. |
| */ |
| break; |
| |
| case R_386_16: |
| if (shn_abs) { |
| /* |
| * Whitelisted absolute symbols do not require |
| * relocation. |
| */ |
| if (is_reloc(S_ABS, symname)) |
| break; |
| |
| if (is_reloc(S_SEG, symname)) { |
| add_reloc(&relocs16, rel->r_offset); |
| break; |
| } |
| } else { |
| if (!is_reloc(S_LIN, symname)) |
| break; |
| } |
| die("Invalid %s %s relocation: %s\n", |
| shn_abs ? "absolute" : "relative", |
| rel_type(r_type), symname); |
| break; |
| |
| case R_386_32: |
| if (shn_abs) { |
| /* |
| * Whitelisted absolute symbols do not require |
| * relocation. |
| */ |
| if (is_reloc(S_ABS, symname)) |
| break; |
| |
| if (is_reloc(S_REL, symname)) { |
| add_reloc(&relocs32, rel->r_offset); |
| break; |
| } |
| } else { |
| if (is_reloc(S_LIN, symname)) |
| add_reloc(&relocs32, rel->r_offset); |
| break; |
| } |
| die("Invalid %s %s relocation: %s\n", |
| shn_abs ? "absolute" : "relative", |
| rel_type(r_type), symname); |
| break; |
| |
| default: |
| die("Unsupported relocation type: %s (%d)\n", |
| rel_type(r_type), r_type); |
| break; |
| } |
| |
| return 0; |
| } |
| |
| #endif |
| |
| static int cmp_relocs(const void *va, const void *vb) |
| { |
| const uint32_t *a, *b; |
| a = va; b = vb; |
| return (*a == *b)? 0 : (*a > *b)? 1 : -1; |
| } |
| |
| static void sort_relocs(struct relocs *r) |
| { |
| qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs); |
| } |
| |
| static int write32(uint32_t v, FILE *f) |
| { |
| unsigned char buf[4]; |
| |
| put_unaligned_le32(v, buf); |
| return fwrite(buf, 1, 4, f) == 4 ? 0 : -1; |
| } |
| |
| static int write32_as_text(uint32_t v, FILE *f) |
| { |
| return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1; |
| } |
| |
| static void emit_relocs(int as_text, int use_real_mode) |
| { |
| int i; |
| int (*write_reloc)(uint32_t, FILE *) = write32; |
| int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym, |
| const char *symname); |
| |
| #if ELF_BITS == 64 |
| if (!use_real_mode) |
| do_reloc = do_reloc64; |
| else |
| die("--realmode not valid for a 64-bit ELF file"); |
| #else |
| if (!use_real_mode) |
| do_reloc = do_reloc32; |
| else |
| do_reloc = do_reloc_real; |
| #endif |
| |
| /* Collect up the relocations */ |
| walk_relocs(do_reloc); |
| |
| if (relocs16.count && !use_real_mode) |
| die("Segment relocations found but --realmode not specified\n"); |
| |
| /* Order the relocations for more efficient processing */ |
| sort_relocs(&relocs32); |
| #if ELF_BITS == 64 |
| sort_relocs(&relocs32neg); |
| sort_relocs(&relocs64); |
| #else |
| sort_relocs(&relocs16); |
| #endif |
| |
| /* 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"); |
| write_reloc = write32_as_text; |
| } |
| |
| if (use_real_mode) { |
| write_reloc(relocs16.count, stdout); |
| for (i = 0; i < relocs16.count; i++) |
| write_reloc(relocs16.offset[i], stdout); |
| |
| write_reloc(relocs32.count, stdout); |
| for (i = 0; i < relocs32.count; i++) |
| write_reloc(relocs32.offset[i], stdout); |
| } else { |
| #if ELF_BITS == 64 |
| /* Print a stop */ |
| write_reloc(0, stdout); |
| |
| /* Now print each relocation */ |
| for (i = 0; i < relocs64.count; i++) |
| write_reloc(relocs64.offset[i], stdout); |
| |
| /* Print a stop */ |
| write_reloc(0, stdout); |
| |
| /* Now print each inverse 32-bit relocation */ |
| for (i = 0; i < relocs32neg.count; i++) |
| write_reloc(relocs32neg.offset[i], stdout); |
| #endif |
| |
| /* Print a stop */ |
| write_reloc(0, stdout); |
| |
| /* Now print each relocation */ |
| for (i = 0; i < relocs32.count; i++) |
| write_reloc(relocs32.offset[i], stdout); |
| } |
| } |
| |
| /* |
| * 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("%s\t%s\t%s\t%s\n", |
| sec_name(sec->shdr.sh_info), |
| rel_type(ELF_R_TYPE(rel->r_info)), |
| symname, |
| sec_name(sym->st_shndx)); |
| return 0; |
| } |
| |
| static void print_reloc_info(void) |
| { |
| printf("reloc section\treloc type\tsymbol\tsymbol section\n"); |
| walk_relocs(do_reloc_info); |
| } |
| |
| #if ELF_BITS == 64 |
| # define process process_64 |
| #else |
| # define process process_32 |
| #endif |
| |
| void process(FILE *fp, int use_real_mode, int as_text, |
| int show_absolute_syms, int show_absolute_relocs, |
| int show_reloc_info) |
| { |
| regex_init(use_real_mode); |
| read_ehdr(fp); |
| read_shdrs(fp); |
| read_strtabs(fp); |
| read_symtabs(fp); |
| read_relocs(fp); |
| if (ELF_BITS == 64) |
| percpu_init(); |
| if (show_absolute_syms) { |
| print_absolute_symbols(); |
| return; |
| } |
| if (show_absolute_relocs) { |
| print_absolute_relocs(); |
| return; |
| } |
| if (show_reloc_info) { |
| print_reloc_info(); |
| return; |
| } |
| emit_relocs(as_text, use_real_mode); |
| } |