// 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; 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|" "__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_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[ehdr.e_shstrndx].strtab; name = "<noname>"; 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"; } 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 < ehdr.e_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); 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]; 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) { int i,j; 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); 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 < ehdr.e_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 < ehdr.e_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 < 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); } } } /* * 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 < ehdr.e_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__irq_stack_union * 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: /* * PC relative relocations don't need to be adjusted unless * referencing a percpu symbol. */ if (is_percpu_sym(sym, symname)) add_reloc(&relocs32neg, offset); 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: /* * NONE can be ignored and PC relative relocations don't * need to be adjusted. */ 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: /* * NONE can be ignored and PC relative relocations don't * need to be adjusted. */ 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); }