Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764506Ab3DDUIP (ORCPT ); Thu, 4 Apr 2013 16:08:15 -0400 Received: from smtp.outflux.net ([198.145.64.163]:38109 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764334Ab3DDUIL (ORCPT ); Thu, 4 Apr 2013 16:08:11 -0400 From: Kees Cook To: linux-kernel@vger.kernel.org Cc: kernel-hardening@lists.openwall.com, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , x86@kernel.org, Jarkko Sakkinen , Matthew Garrett , Matt Fleming , Eric Northup , Dan Rosenberg , Julien Tinnes , Will Drewry , Kees Cook Subject: [PATCH 2/3] x86: build reloc tool for both 64 and 32 bit Date: Thu, 4 Apr 2013 13:07:34 -0700 Message-Id: <1365106055-22939-3-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1365106055-22939-1-git-send-email-keescook@chromium.org> References: <1365106055-22939-1-git-send-email-keescook@chromium.org> X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 31020 Lines: 1074 Add logic for 64-bit kernel relocations. Since there is no need to handle 32 and 64 bit at the same time, refactor away most of the 32/64 bit ELF differences and split the build into producing two separate binaries. Additionally switches to using realloc instead of a two-pass approach. Heavily based on work by Neill Clift and Michael Davidson. Signed-off-by: Kees Cook Cc: Eric Northup --- arch/x86/boot/compressed/Makefile | 2 +- arch/x86/realmode/rm/Makefile | 2 +- arch/x86/tools/.gitignore | 3 +- arch/x86/tools/Makefile | 14 +- arch/x86/tools/relocs.c | 717 ++++++++++++++++++++++++++----------- arch/x86/tools/relocs_32.c | 1 + arch/x86/tools/relocs_64.c | 2 + 7 files changed, 533 insertions(+), 208 deletions(-) create mode 100644 arch/x86/tools/relocs_32.c create mode 100644 arch/x86/tools/relocs_64.c diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 376ef47..deaed7d 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -48,7 +48,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE targets += vmlinux.bin.all vmlinux.relocs -CMD_RELOCS = arch/x86/tools/relocs +CMD_RELOCS = arch/x86/tools/relocs_$(BITS) quiet_cmd_relocs = RELOCS $@ cmd_relocs = $(CMD_RELOCS) $< > $@;$(CMD_RELOCS) --abs-relocs $< $(obj)/vmlinux.relocs: vmlinux FORCE diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index 8869287..2b1e429 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -56,7 +56,7 @@ $(obj)/realmode.bin: $(obj)/realmode.elf $(obj)/realmode.relocs $(call if_changed,objcopy) quiet_cmd_relocs = RELOCS $@ - cmd_relocs = arch/x86/tools/relocs --realmode $< > $@ + cmd_relocs = arch/x86/tools/relocs_32 --realmode $< > $@ targets += realmode.relocs $(obj)/realmode.relocs: $(obj)/realmode.elf FORCE diff --git a/arch/x86/tools/.gitignore b/arch/x86/tools/.gitignore index be0ed06..51374a2 100644 --- a/arch/x86/tools/.gitignore +++ b/arch/x86/tools/.gitignore @@ -1 +1,2 @@ -relocs +relocs_32 +relocs_64 diff --git a/arch/x86/tools/Makefile b/arch/x86/tools/Makefile index bae601f..8c3b17a 100644 --- a/arch/x86/tools/Makefile +++ b/arch/x86/tools/Makefile @@ -37,6 +37,16 @@ $(obj)/test_get_len.o: $(srctree)/arch/x86/lib/insn.c $(srctree)/arch/x86/lib/in $(obj)/insn_sanity.o: $(srctree)/arch/x86/lib/insn.c $(srctree)/arch/x86/lib/inat.c $(srctree)/arch/x86/include/asm/inat_types.h $(srctree)/arch/x86/include/asm/inat.h $(srctree)/arch/x86/include/asm/insn.h $(objtree)/arch/x86/lib/inat-tables.c +$(obj)/relocs_64.o: $(srctree)/arch/x86/tools/relocs.c $(srctree)/arch/x86/tools/relocs_64.c +$(obj)/relocs_32.o: $(srctree)/arch/x86/tools/relocs.c $(srctree)/arch/x86/tools/relocs_32.c + HOST_EXTRACFLAGS += -I$(srctree)/tools/include -hostprogs-y += relocs -relocs: $(obj)/relocs +hostprogs-y += relocs_$(BITS) +relocs_binaries = relocs_$(BITS) +ifeq ($(CONFIG_64BIT),y) + hostprogs-y += relocs_32 + relocs_binaries += relocs_32 +endif +relocs: $(relocs_binaries) +relocs_64: $(obj)/relocs_64 +relocs_32: $(obj)/relocs_32 diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index 79d67bd..63c5090 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -2,6 +2,7 @@ #include #include #include +#include #include #include #include @@ -12,21 +13,78 @@ #include #include +#ifdef CONFIG_X86_64 +#define ELF_BITS 64 +#define ELF_MACHINE EM_X86_64 +#define ELF_MACHINE_NAME "x86_64" +#define SHT_REL_TYPE SHT_RELA +#define Elf_Rel Elf64_Rela +#else +#define ELF_BITS 32 +#define ELF_MACHINE EM_386 +#define ELF_MACHINE_NAME "i386" +#define SHT_REL_TYPE SHT_REL +#define Elf_Rel Elf32_Rel +#endif + +#if (ELF_BITS == 64) +#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) +#else +#define ELF_CLASS ELFCLASS32 +#define ELF_R_SYM(val) ELF32_R_SYM(val) +#define ELF_R_TYPE(val) ELF32_R_TYPE(val) +#define ELF_ST_TYPE(o) ELF32_ST_TYPE(o) +#define ELF_ST_BIND(o) ELF32_ST_BIND(o) +#define ELF_ST_VISIBILITY(o) ELF32_ST_VISIBILITY(o) +#endif + +#define ElfW(type) _ElfW(ELF_BITS, type) +#define _ElfW(bits, type) __ElfW(bits, type) +#define __ElfW(bits, type) Elf##bits##_##type + static void die(char *fmt, ...); #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) -static Elf32_Ehdr ehdr; -static unsigned long reloc_count, reloc_idx; -static unsigned long *relocs; -static unsigned long reloc16_count, reloc16_idx; -static unsigned long *relocs16; +static ElfW(Ehdr) ehdr; + +struct relocs { + uint32_t *offset; + unsigned long count; + unsigned long size; +}; + +struct relocs relocs16; +struct relocs relocs32; +#ifdef CONFIG_X86_64 +struct relocs relocs64; +#endif + +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; +} struct section { - Elf32_Shdr shdr; - struct section *link; - Elf32_Sym *symtab; - Elf32_Rel *reltab; - char *strtab; + ElfW(Shdr) shdr; + struct section *link; + ElfW(Sym) *symtab; + Elf_Rel *reltab; + char *strtab; }; static struct section *secs; @@ -49,6 +107,9 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = { "^(xen_irq_disable_direct_reloc$|" "xen_save_fl_direct_reloc$|" "VDSO|" +#ifdef CONFIG_X86_64 + "__vvar_page|" +#endif "__crc_)", /* @@ -72,6 +133,11 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = { "__end_rodata|" "__initramfs_start|" "(jiffies|jiffies_64)|" +#ifdef CONFIG_X86_64 + "__per_cpu_load|" + "init_per_cpu__.*|" + "__end_rodata_hpage_align|" +#endif "_end)$" }; @@ -198,6 +264,24 @@ static const char *rel_type(unsigned type) { static const char *type_name[] = { #define REL_TYPE(X) [X] = #X +#ifdef CONFIG_X86_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), @@ -213,6 +297,7 @@ static const char *rel_type(unsigned type) 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"; @@ -240,7 +325,7 @@ static const char *sec_name(unsigned shndx) return name; } -static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym) +static const char *sym_name(const char *sym_strtab, ElfW(Sym) *sym) { const char *name; name = ""; @@ -253,15 +338,45 @@ static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym) return name; } +#ifdef CONFIG_X86_64 +static ElfW(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; + ElfW(Sym) *symtab; + ElfW(Sym) *sym; + + if (sec->shdr.sh_type != SHT_SYMTAB) + continue; + + nsyms = sec->shdr.sh_size/sizeof(ElfW(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; +} +#endif #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) @@ -274,6 +389,25 @@ static uint32_t elf32_to_cpu(uint32_t val) return le32_to_cpu(val); } +#if (ELF_BITS == 64) +static uint64_t elf64_to_cpu(uint64_t val) +{ + return le64_to_cpu(val); +} +#endif + +#define elf_half_to_cpu(x) elf16_to_cpu(x) +#define elf_word_to_cpu(x) elf32_to_cpu(x) +#if (ELF_BITS == 64) +#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) { @@ -283,8 +417,8 @@ static void read_ehdr(FILE *fp) if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) { die("No ELF magic\n"); } - if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) { - die("Not a 32 bit executable\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"); @@ -293,36 +427,36 @@ static void read_ehdr(FILE *fp) die("Unknown ELF version\n"); } /* Convert the fields to native endian */ - ehdr.e_type = elf16_to_cpu(ehdr.e_type); - ehdr.e_machine = elf16_to_cpu(ehdr.e_machine); - ehdr.e_version = elf32_to_cpu(ehdr.e_version); - ehdr.e_entry = elf32_to_cpu(ehdr.e_entry); - ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff); - ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff); - ehdr.e_flags = elf32_to_cpu(ehdr.e_flags); - ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize); - ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize); - ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum); - ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize); - ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum); - ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx); + 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 != EM_386) { - die("Not for x86\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(Elf32_Ehdr)) { + if (ehdr.e_ehsize != sizeof(ElfW(Ehdr))) { die("Bad Elf header size\n"); } - if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) { + if (ehdr.e_phentsize != sizeof(ElfW(Phdr))) { die("Bad program header entry\n"); } - if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) { + if (ehdr.e_shentsize != sizeof(ElfW(Shdr))) { die("Bad section header entry\n"); } if (ehdr.e_shstrndx >= ehdr.e_shnum) { @@ -333,7 +467,7 @@ static void read_ehdr(FILE *fp) static void read_shdrs(FILE *fp) { int i; - Elf32_Shdr shdr; + ElfW(Shdr) shdr; secs = calloc(ehdr.e_shnum, sizeof(struct section)); if (!secs) { @@ -349,16 +483,16 @@ static void read_shdrs(FILE *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 = elf32_to_cpu(shdr.sh_name); - sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type); - sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags); - sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr); - sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset); - sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size); - sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link); - sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info); - sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign); - sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize); + 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]; } @@ -412,12 +546,12 @@ static void read_symtabs(FILE *fp) die("Cannot read symbol table: %s\n", strerror(errno)); } - for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) { - Elf32_Sym *sym = &sec->symtab[j]; - sym->st_name = elf32_to_cpu(sym->st_name); - sym->st_value = elf32_to_cpu(sym->st_value); - sym->st_size = elf32_to_cpu(sym->st_size); - sym->st_shndx = elf16_to_cpu(sym->st_shndx); + for (j = 0; j < sec->shdr.sh_size/sizeof(ElfW(Sym)); j++) { + ElfW(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); } } } @@ -428,7 +562,7 @@ 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) { + if (sec->shdr.sh_type != SHT_REL_TYPE) { continue; } sec->reltab = malloc(sec->shdr.sh_size); @@ -445,10 +579,13 @@ static void read_relocs(FILE *fp) die("Cannot read symbol table: %s\n", strerror(errno)); } - for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { - Elf32_Rel *rel = &sec->reltab[j]; - rel->r_offset = elf32_to_cpu(rel->r_offset); - rel->r_info = elf32_to_cpu(rel->r_info); + 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 } } } @@ -468,19 +605,25 @@ static void print_absolute_symbols(void) continue; } sym_strtab = sec->link->strtab; - for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) { - Elf32_Sym *sym; + for (j = 0; j < sec->shdr.sh_size/sizeof(ElfW(Sym)); j++) { + ElfW(Sym) *sym; const char *name; sym = &sec->symtab[j]; name = sym_name(sym_strtab, sym); if (sym->st_shndx != SHN_ABS) { continue; } - printf("%5d %08x %5d %10s %10s %12s %s\n", +#if (ELF_BITS == 64) + printf("%5d %016"PRIx64" %5"PRId64 + " %10s %10s %12s %s\n", +#else + printf("%5d %08"PRIx32" %5"PRId32 + " %10s %10s %12s %s\n", +#endif j, sym->st_value, sym->st_size, - sym_type(ELF32_ST_TYPE(sym->st_info)), - sym_bind(ELF32_ST_BIND(sym->st_info)), - sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)), + 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); } } @@ -495,9 +638,9 @@ static void print_absolute_relocs(void) struct section *sec = &secs[i]; struct section *sec_applies, *sec_symtab; char *sym_strtab; - Elf32_Sym *sh_symtab; + ElfW(Sym) *sh_symtab; int j; - if (sec->shdr.sh_type != SHT_REL) { + if (sec->shdr.sh_type != SHT_REL_TYPE) { continue; } sec_symtab = sec->link; @@ -507,12 +650,12 @@ static void print_absolute_relocs(void) } sh_symtab = sec_symtab->symtab; sym_strtab = sec_symtab->link->strtab; - for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { - Elf32_Rel *rel; - Elf32_Sym *sym; + for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) { + Elf_Rel *rel; + ElfW(Sym) *sym; const char *name; rel = &sec->reltab[j]; - sym = &sh_symtab[ELF32_R_SYM(rel->r_info)]; + sym = &sh_symtab[ELF_R_SYM(rel->r_info)]; name = sym_name(sym_strtab, sym); if (sym->st_shndx != SHN_ABS) { continue; @@ -542,10 +685,16 @@ static void print_absolute_relocs(void) printed = 1; } - printf("%08x %08x %10s %08x %s\n", +#if (ELF_BITS == 64) + printf("%016"PRIx64" %016"PRIx64 + " %10s %016"PRIx64" %s\n", +#else + printf("%08"PRIx32" %08"PRIx32 + " %10s %08"PRIx32" %s\n", +#endif rel->r_offset, rel->r_info, - rel_type(ELF32_R_TYPE(rel->r_info)), + rel_type(ELF_R_TYPE(rel->r_info)), sym->st_value, name); } @@ -555,19 +704,20 @@ static void print_absolute_relocs(void) printf("\n"); } -static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym), - int use_real_mode) + +static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *, + ElfW(Sym) *, const char *)) { int i; /* Walk through the relocations */ for (i = 0; i < ehdr.e_shnum; i++) { char *sym_strtab; - Elf32_Sym *sh_symtab; + ElfW(Sym) *sh_symtab; struct section *sec_applies, *sec_symtab; int j; struct section *sec = &secs[i]; - if (sec->shdr.sh_type != SHT_REL) { + if (sec->shdr.sh_type != SHT_REL_TYPE) { continue; } sec_symtab = sec->link; @@ -577,101 +727,276 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym), } sh_symtab = sec_symtab->symtab; sym_strtab = sec_symtab->link->strtab; - for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { - Elf32_Rel *rel; - Elf32_Sym *sym; - unsigned r_type; - const char *symname; - int shn_abs; - rel = &sec->reltab[j]; - sym = &sh_symtab[ELF32_R_SYM(rel->r_info)]; - r_type = ELF32_R_TYPE(rel->r_info); - - shn_abs = sym->st_shndx == SHN_ABS; - - switch (r_type) { - case R_386_NONE: - case R_386_PC32: - case R_386_PC16: - case R_386_PC8: - /* - * NONE can be ignored and and PC relative - * relocations don't need to be adjusted. - */ - break; + for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) { + Elf_Rel *rel = &sec->reltab[j]; + ElfW(Sym) *sym = &sh_symtab[ELF_R_SYM(rel->r_info)]; + const char *symname = sym_name(sym_strtab, sym); - case R_386_16: - symname = sym_name(sym_strtab, sym); - if (!use_real_mode) - goto bad; - if (shn_abs) { - if (is_reloc(S_ABS, symname)) - break; - else if (!is_reloc(S_SEG, symname)) - goto bad; - } else { - if (is_reloc(S_LIN, symname)) - goto bad; - else - break; - } - visit(rel, sym); - break; + process(sec, rel, sym, symname); + } + } +} - case R_386_32: - symname = sym_name(sym_strtab, sym); - if (shn_abs) { - if (is_reloc(S_ABS, symname)) - break; - else if (!is_reloc(S_REL, symname)) - goto bad; - } else { - if (use_real_mode && - !is_reloc(S_LIN, symname)) - break; - } - visit(rel, sym); - break; - default: - die("Unsupported relocation type: %s (%d)\n", - rel_type(r_type), r_type); +#ifdef CONFIG_X86_64 + +#define PER_CPU_SECTION ".data..percpu" +static int per_cpu_shndx = -1; +ElfW(Addr) per_cpu_load_addr; + +/* + * 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 void percpu_init(void) +{ + int i; + for (i = 0; i < ehdr.e_shnum; i++) { + ElfW(Sym) *sym; + if (strcmp(sec_name(i), PER_CPU_SECTION)) + 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; + } +} + +/* + * Check to see if a symbol lies in the .data..percpu section. + * For some as yet not understood reason the "__init_begin" + * symbol which immediately preceeds the .data..percpu section + * also shows up as it it were part of it so we do an explict + * check for that symbol name and ignore it. + */ +static int is_percpu_sym(ElfW(Sym) *sym, const char *symname) +{ + return (sym->st_shndx == per_cpu_shndx) && + strcmp(symname, "__init_begin"); +} + + +static int do_reloc(struct section *sec, Elf64_Rela *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: + case R_X86_64_PC32: + /* + * NONE can be ignored and PC relative + * relocations don't need to be adjusted. + */ + 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; - bad: - symname = sym_name(sym_strtab, sym); - die("Invalid %s %s relocation: %s\n", - shn_abs ? "absolute" : "relative", - rel_type(r_type), symname); - } + + 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; } -static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym) +#else + +static int do_reloc(struct section *sec, Elf32_Rel *rel, ElfW(Sym) *sym, + const char *symname) { - if (ELF32_R_TYPE(rel->r_info) == R_386_16) - reloc16_count++; - else - reloc_count++; + 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; } +#endif -static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym) + +static int do_reloc_real(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, + const char *symname) { - /* Remember the address that needs to be adjusted. */ - if (ELF32_R_TYPE(rel->r_info) == R_386_16) - relocs16[reloc16_idx++] = rel->r_offset; - else - relocs[reloc_idx++] = rel->r_offset; + 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) { + 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) { + 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; } + static int cmp_relocs(const void *va, const void *vb) { - const unsigned long *a, *b; + const uint32_t *a, *b; a = va; b = vb; return (*a == *b)? 0 : (*a > *b)? 1 : -1; } -static int write32(unsigned int v, FILE *f) +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]; @@ -679,79 +1004,62 @@ static int write32(unsigned int v, FILE *f) 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; - /* Count how many relocations I have and allocate space for them. */ - reloc_count = 0; - walk_relocs(count_reloc, use_real_mode); - relocs = malloc(reloc_count * sizeof(relocs[0])); - if (!relocs) { - die("malloc of %d entries for relocs failed\n", - reloc_count); - } + int (*write_reloc)(uint32_t, FILE *) = write32; - relocs16 = malloc(reloc16_count * sizeof(relocs[0])); - if (!relocs16) { - die("malloc of %d entries for relocs16 failed\n", - reloc16_count); - } /* Collect up the relocations */ - reloc_idx = 0; - walk_relocs(collect_reloc, use_real_mode); + walk_relocs(use_real_mode ? do_reloc_real : do_reloc); - if (reloc16_count && !use_real_mode) + if (relocs16.count && !use_real_mode) die("Segment relocations found but --realmode not specified\n"); /* Order the relocations for more efficient processing */ - qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs); - qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs); + sort_relocs(&relocs16); + sort_relocs(&relocs32); +#ifdef CONFIG_X86_64 + sort_relocs(&relocs64); +#endif + + /* output the relocations */ - /* 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"); - if (use_real_mode) { - printf("\t.long %lu\n", reloc16_count); - for (i = 0; i < reloc16_count; i++) - printf("\t.long 0x%08lx\n", relocs16[i]); - printf("\t.long %lu\n", reloc_count); - for (i = 0; i < reloc_count; i++) { - printf("\t.long 0x%08lx\n", relocs[i]); - } - } else { - /* Print a stop */ - printf("\t.long 0x%08lx\n", (unsigned long)0); - for (i = 0; i < reloc_count; i++) { - printf("\t.long 0x%08lx\n", relocs[i]); - } - } - - printf("\n"); + write_reloc = write32_as_text; } - else { - if (use_real_mode) { - write32(reloc16_count, stdout); - for (i = 0; i < reloc16_count; i++) - write32(relocs16[i], stdout); - write32(reloc_count, stdout); - - /* Now print each relocation */ - for (i = 0; i < reloc_count; i++) - write32(relocs[i], stdout); - } else { - /* Print a stop */ - write32(0, stdout); - /* Now print each relocation */ - for (i = 0; i < reloc_count; i++) { - write32(relocs[i], stdout); - } - } + 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 { +#ifdef CONFIG_X86_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); +#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); } + } static void usage(void) @@ -812,6 +1120,9 @@ int main(int argc, char **argv) read_strtabs(fp); read_symtabs(fp); read_relocs(fp); +#ifdef CONFIG_X86_64 + percpu_init(); +#endif if (show_absolute_syms) { print_absolute_symbols(); goto out; diff --git a/arch/x86/tools/relocs_32.c b/arch/x86/tools/relocs_32.c new file mode 100644 index 0000000..8cf7e94 --- /dev/null +++ b/arch/x86/tools/relocs_32.c @@ -0,0 +1 @@ +#include "relocs.c" diff --git a/arch/x86/tools/relocs_64.c b/arch/x86/tools/relocs_64.c new file mode 100644 index 0000000..419b05a --- /dev/null +++ b/arch/x86/tools/relocs_64.c @@ -0,0 +1,2 @@ +#define CONFIG_X86_64 1 +#include "relocs.c" -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/