From 4eefbe792baedb474e256d35370849992fcf1c79 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Wed, 10 Apr 2013 12:24:22 -0700
Subject: x86: Use a read-only IDT alias on all CPUs

Make a copy of the IDT (as seen via the "sidt" instruction) read-only.
This primarily removes the IDT from being a target for arbitrary memory
write attacks, and has the added benefit of also not leaking the kernel
base offset, if it has been relocated.

We already did this on vendor == Intel and family == 5 because of the
F0 0F bug -- regardless of if a particular CPU had the F0 0F bug or
not.  Since the workaround was so cheap, there simply was no reason to
be very specific.  This patch extends the readonly alias to all CPUs,
but does not activate the #PF to #UD conversion code needed to deliver
the proper exception in the F0 0F case except on Intel family 5
processors.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20130410192422.GA17344@www.outflux.net
Cc: Eric Northup <digitaleric@google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/fixmap.h |  4 +---
 arch/x86/kernel/cpu/intel.c   | 18 +-----------------
 arch/x86/kernel/traps.c       |  9 +++++++++
 arch/x86/xen/mmu.c            |  4 +---
 4 files changed, 12 insertions(+), 23 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index a09c28571064..51b9e322cb8f 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -104,9 +104,7 @@ enum fixed_addresses {
 	FIX_LI_PCIA,	/* Lithium PCI Bridge A */
 	FIX_LI_PCIB,	/* Lithium PCI Bridge B */
 #endif
-#ifdef CONFIG_X86_F00F_BUG
-	FIX_F00F_IDT,	/* Virtual mapping for IDT */
-#endif
+	FIX_RO_IDT,	/* Virtual mapping for read-only IDT */
 #ifdef CONFIG_X86_CYCLONE_TIMER
 	FIX_CYCLONE_TIMER, /*cyclone timer register*/
 #endif
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1905ce98bee0..71700247a5d7 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -164,20 +164,6 @@ int __cpuinit ppro_with_ram_bug(void)
 	return 0;
 }
 
-#ifdef CONFIG_X86_F00F_BUG
-static void __cpuinit trap_init_f00f_bug(void)
-{
-	__set_fixmap(FIX_F00F_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
-
-	/*
-	 * Update the IDT descriptor and reload the IDT so that
-	 * it uses the read-only mapped virtual address.
-	 */
-	idt_descr.address = fix_to_virt(FIX_F00F_IDT);
-	load_idt(&idt_descr);
-}
-#endif
-
 static void __cpuinit intel_smp_check(struct cpuinfo_x86 *c)
 {
 	/* calling is from identify_secondary_cpu() ? */
@@ -206,8 +192,7 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
 	/*
 	 * All current models of Pentium and Pentium with MMX technology CPUs
 	 * have the F0 0F bug, which lets nonprivileged users lock up the
-	 * system.
-	 * Note that the workaround only should be initialized once...
+	 * system. Announce that the fault handler will be checking for it.
 	 */
 	c->f00f_bug = 0;
 	if (!paravirt_enabled() && c->x86 == 5) {
@@ -215,7 +200,6 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
 
 		c->f00f_bug = 1;
 		if (!f00f_workaround_enabled) {
-			trap_init_f00f_bug();
 			printk(KERN_NOTICE "Intel Pentium with F0 0F bug - workaround enabled.\n");
 			f00f_workaround_enabled = 1;
 		}
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 68bda7a84159..10e24462c058 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -56,6 +56,7 @@
 #include <asm/fpu-internal.h>
 #include <asm/mce.h>
 #include <asm/context_tracking.h>
+#include <asm/fixmap.h>
 
 #include <asm/mach_traps.h>
 
@@ -752,6 +753,14 @@ void __init trap_init(void)
 	set_bit(SYSCALL_VECTOR, used_vectors);
 #endif
 
+	/*
+	 * Set the IDT descriptor to a fixed read-only location, so that the
+	 * "sidt" instruction will not leak the location of the kernel, and
+	 * to defend the IDT against arbitrary memory write vulnerabilities.
+	 * It will be reloaded in cpu_init() */
+	__set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
+	idt_descr.address = fix_to_virt(FIX_RO_IDT);
+
 	/*
 	 * Should be a barrier for any external CPU state:
 	 */
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 6afbb2ca9a0a..8bc4decb14ca 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2039,9 +2039,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
 
 	switch (idx) {
 	case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
-#ifdef CONFIG_X86_F00F_BUG
-	case FIX_F00F_IDT:
-#endif
+	case FIX_RO_IDT:
 #ifdef CONFIG_X86_32
 	case FIX_WP_TEST:
 	case FIX_VDSO:
-- 
cgit v1.2.3


From bf11655cf2ecdcfaacbc8324da4a3edfe276ba9d Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 12 Apr 2013 13:13:42 -0700
Subject: x86, relocs: Generalize ELF structure names

In preparation for making the reloc tool operate on 64-bit relocations,
generalize the structure names for easy recompilation via #defines.

Based on work by Neill Clift and Michael Davidson.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1365797627-20874-2-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/tools/relocs.c | 170 ++++++++++++++++++++++++++++--------------------
 1 file changed, 99 insertions(+), 71 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 79d67bd507fa..fd28ef7dfbb9 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -12,20 +12,42 @@
 #include <regex.h>
 #include <tools/le_byteshift.h>
 
+#define ElfW(type)		_ElfW(ELF_BITS, type)
+#define _ElfW(bits, type)	__ElfW(bits, type)
+#define __ElfW(bits, type)	Elf##bits##_##type
+
+#define ELF_BITS		32
+#define ELF_MACHINE		EM_386
+#define ELF_MACHINE_NAME	"i386"
+#define SHT_REL_TYPE		SHT_REL
+
+#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)
+
+#define Elf_Rel			ElfW(Rel)
+#define Elf_Ehdr		ElfW(Ehdr)
+#define Elf_Phdr		ElfW(Phdr)
+#define Elf_Shdr		ElfW(Shdr)
+#define Elf_Sym			ElfW(Sym)
+
 static void die(char *fmt, ...);
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
-static Elf32_Ehdr ehdr;
+static Elf_Ehdr ehdr;
 static unsigned long reloc_count, reloc_idx;
 static unsigned long *relocs;
 static unsigned long reloc16_count, reloc16_idx;
 static unsigned long *relocs16;
 
 struct section {
-	Elf32_Shdr     shdr;
+	Elf_Shdr       shdr;
 	struct section *link;
-	Elf32_Sym      *symtab;
-	Elf32_Rel      *reltab;
+	Elf_Sym        *symtab;
+	Elf_Rel        *reltab;
 	char           *strtab;
 };
 static struct section *secs;
@@ -240,7 +262,7 @@ 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, Elf_Sym *sym)
 {
 	const char *name;
 	name = "<noname>";
@@ -274,6 +296,12 @@ 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)
+#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)
+
 static void read_ehdr(FILE *fp)
 {
 	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
@@ -283,8 +311,8 @@ 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 +321,36 @@ 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(Elf_Ehdr)) {
 		die("Bad Elf header size\n");
 	}
-	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
+	if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
 		die("Bad program header entry\n");
 	}
-	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
+	if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
 		die("Bad section header entry\n");
 	}
 	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
@@ -333,7 +361,7 @@ static void read_ehdr(FILE *fp)
 static void read_shdrs(FILE *fp)
 {
 	int i;
-	Elf32_Shdr shdr;
+	Elf_Shdr shdr;
 
 	secs = calloc(ehdr.e_shnum, sizeof(struct section));
 	if (!secs) {
@@ -349,16 +377,16 @@ 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 +440,12 @@ 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(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);
 		}
 	}
 }
@@ -428,7 +456,7 @@ 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 +473,10 @@ 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);
 		}
 	}
 }
@@ -468,8 +496,8 @@ 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(Elf_Sym); j++) {
+			Elf_Sym *sym;
 			const char *name;
 			sym = &sec->symtab[j];
 			name = sym_name(sym_strtab, sym);
@@ -478,9 +506,9 @@ static void print_absolute_symbols(void)
 			}
 			printf("%5d %08x %5d %10s %10s %12s %s\n",
 				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 +523,9 @@ static void print_absolute_relocs(void)
 		struct section *sec = &secs[i];
 		struct section *sec_applies, *sec_symtab;
 		char *sym_strtab;
-		Elf32_Sym *sh_symtab;
+		Elf_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 +535,12 @@ 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;
+			Elf_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;
@@ -545,7 +573,7 @@ static void print_absolute_relocs(void)
 			printf("%08x %08x %10s %08x  %s\n",
 				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 +583,19 @@ static void print_absolute_relocs(void)
 		printf("\n");
 }
 
-static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
+static void walk_relocs(void (*visit)(Elf_Rel *rel, Elf_Sym *sym),
 			int use_real_mode)
 {
 	int i;
 	/* Walk through the relocations */
 	for (i = 0; i < ehdr.e_shnum; i++) {
 		char *sym_strtab;
-		Elf32_Sym *sh_symtab;
+		Elf_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;
@@ -577,16 +605,16 @@ 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;
+		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
+			Elf_Rel *rel;
+			Elf_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);
+			sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
+			r_type = ELF_R_TYPE(rel->r_info);
 
 			shn_abs = sym->st_shndx == SHN_ABS;
 
@@ -647,18 +675,18 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 	}
 }
 
-static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
+static void count_reloc(Elf_Rel *rel, Elf_Sym *sym)
 {
-	if (ELF32_R_TYPE(rel->r_info) == R_386_16)
+	if (ELF_R_TYPE(rel->r_info) == R_386_16)
 		reloc16_count++;
 	else
 		reloc_count++;
 }
 
-static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
+static void collect_reloc(Elf_Rel *rel, Elf_Sym *sym)
 {
 	/* Remember the address that needs to be adjusted. */
-	if (ELF32_R_TYPE(rel->r_info) == R_386_16)
+	if (ELF_R_TYPE(rel->r_info) == R_386_16)
 		relocs16[reloc16_idx++] = rel->r_offset;
 	else
 		relocs[reloc_idx++] = rel->r_offset;
-- 
cgit v1.2.3


From 5d442e63d6a1b5736fd48a907bd7d2d87e411816 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 12 Apr 2013 13:13:43 -0700
Subject: x86, relocs: Consolidate processing logic

Instead of counting and then processing relocations, do it in a single
pass. This splits the processing logic into separate functions for
realmode and 32-bit (and paves the way for 64-bit). Also extracts helper
functions when emitting relocations.

Based on work by Neill Clift and Michael Davidson.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1365797627-20874-3-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/tools/relocs.c | 304 +++++++++++++++++++++++++++---------------------
 1 file changed, 170 insertions(+), 134 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index fd28ef7dfbb9..bdc5930b3a1b 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -2,6 +2,7 @@
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <inttypes.h>
 #include <string.h>
 #include <errno.h>
 #include <unistd.h>
@@ -38,10 +39,15 @@ static void die(char *fmt, ...);
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 static Elf_Ehdr ehdr;
-static unsigned long reloc_count, reloc_idx;
-static unsigned long *relocs;
-static unsigned long reloc16_count, reloc16_idx;
-static unsigned long *relocs16;
+
+struct relocs {
+	uint32_t	*offset;
+	unsigned long	count;
+	unsigned long	size;
+};
+
+static struct relocs relocs16;
+static struct relocs relocs32;
 
 struct section {
 	Elf_Shdr       shdr;
@@ -583,8 +589,23 @@ static void print_absolute_relocs(void)
 		printf("\n");
 }
 
-static void walk_relocs(void (*visit)(Elf_Rel *rel, Elf_Sym *sym),
-			int use_real_mode)
+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 */
@@ -606,100 +627,142 @@ static void walk_relocs(void (*visit)(Elf_Rel *rel, Elf_Sym *sym),
 		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;
-			unsigned r_type;
-			const char *symname;
-			int shn_abs;
+			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);
 
-			rel = &sec->reltab[j];
-			sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
-			r_type = ELF_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.
-				 */
+			process(sec, rel, sym, symname);
+		}
+	}
+}
+
+static int do_reloc(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;
 
-			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);
+			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;
 
-			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);
+			if (is_reloc(S_SEG, symname)) {
+				add_reloc(&relocs16, rel->r_offset);
+				break;
+			}
+		} else {
+			if (!is_reloc(S_LIN, symname))
 				break;
-			default:
-				die("Unsupported relocation type: %s (%d)\n",
-				    rel_type(r_type), r_type);
+		}
+		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;
-			bad:
-				symname = sym_name(sym_strtab, sym);
-				die("Invalid %s %s relocation: %s\n",
-				    shn_abs ? "absolute" : "relative",
-				    rel_type(r_type), symname);
 			}
+		} 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;
 
-static void count_reloc(Elf_Rel *rel, Elf_Sym *sym)
-{
-	if (ELF_R_TYPE(rel->r_info) == R_386_16)
-		reloc16_count++;
-	else
-		reloc_count++;
-}
+	default:
+		die("Unsupported relocation type: %s (%d)\n",
+		    rel_type(r_type), r_type);
+		break;
+	}
 
-static void collect_reloc(Elf_Rel *rel, Elf_Sym *sym)
-{
-	/* Remember the address that needs to be adjusted. */
-	if (ELF_R_TYPE(rel->r_info) == R_386_16)
-		relocs16[reloc16_idx++] = rel->r_offset;
-	else
-		relocs[reloc_idx++] = rel->r_offset;
+	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];
 
@@ -707,33 +770,25 @@ 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);
 
 	/* Print the relocations */
 	if (as_text) {
@@ -742,43 +797,24 @@ static void emit_relocs(int as_text, int use_real_mode)
 		 */
 		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 {
+		/* Print a stop */
+		write_reloc(0, stdout);
+
+		/* Now print each relocation */
+		for (i = 0; i < relocs32.count; i++)
+			write_reloc(relocs32.offset[i], stdout);
 	}
 }
 
-- 
cgit v1.2.3


From 946166af95d1defacfbc21e7c902d0556a2a7660 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 12 Apr 2013 13:13:44 -0700
Subject: x86, relocs: Add 64-bit ELF support to relocs tool

This adds the ability to process relocations from the 64-bit kernel ELF,
if built with ELF_BITS=64 defined. The special case for the percpu area is
handled, along with some other symbols specific to the 64-bit kernel.

Based on work by Neill Clift and Michael Davidson.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1365797627-20874-4-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/tools/relocs.c | 267 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 261 insertions(+), 6 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index bdc5930b3a1b..1f7ff3d11a05 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -17,19 +17,39 @@
 #define _ElfW(bits, type)	__ElfW(bits, type)
 #define __ElfW(bits, type)	Elf##bits##_##type
 
+#ifndef ELF_BITS
 #define ELF_BITS		32
+#endif
+
+#if (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_MACHINE		EM_386
 #define ELF_MACHINE_NAME	"i386"
 #define SHT_REL_TYPE		SHT_REL
+#define Elf_Rel			ElfW(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 Elf_Rel			ElfW(Rel)
+#define Elf_Addr		ElfW(Addr)
 #define Elf_Ehdr		ElfW(Ehdr)
 #define Elf_Phdr		ElfW(Phdr)
 #define Elf_Shdr		ElfW(Shdr)
@@ -48,6 +68,7 @@ struct relocs {
 
 static struct relocs relocs16;
 static struct relocs relocs32;
+static struct relocs relocs64;
 
 struct section {
 	Elf_Shdr       shdr;
@@ -77,6 +98,9 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"^(xen_irq_disable_direct_reloc$|"
 	"xen_save_fl_direct_reloc$|"
 	"VDSO|"
+#if (ELF_BITS == 64)
+	"__vvar_page|"
+#endif
 	"__crc_)",
 
 /*
@@ -100,6 +124,11 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"__end_rodata|"
 	"__initramfs_start|"
 	"(jiffies|jiffies_64)|"
+#if (ELF_BITS == 64)
+	"__per_cpu_load|"
+	"init_per_cpu__.*|"
+	"__end_rodata_hpage_align|"
+#endif
 	"_end)$"
 };
 
@@ -226,6 +255,24 @@ 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),
@@ -241,6 +288,7 @@ 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";
@@ -281,15 +329,42 @@ static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
 	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)
@@ -304,9 +379,20 @@ static uint32_t elf32_to_cpu(uint32_t 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)
 {
@@ -483,6 +569,9 @@ static void read_relocs(FILE *fp)
 			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
 		}
 	}
 }
@@ -491,6 +580,13 @@ static void read_relocs(FILE *fp)
 static void print_absolute_symbols(void)
 {
 	int i;
+	const char *format;
+
+	if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+		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++) {
@@ -510,7 +606,7 @@ static void print_absolute_symbols(void)
 			if (sym->st_shndx != SHN_ABS) {
 				continue;
 			}
-			printf("%5d %08x %5d %10s %10s %12s %s\n",
+			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)),
@@ -524,6 +620,12 @@ static void print_absolute_symbols(void)
 static void print_absolute_relocs(void)
 {
 	int i, printed = 0;
+	const char *format;
+
+	if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+		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];
@@ -576,7 +678,7 @@ static void print_absolute_relocs(void)
 				printed = 1;
 			}
 
-			printf("%08x %08x %10s %08x  %s\n",
+			printf(format,
 				rel->r_offset,
 				rel->r_info,
 				rel_type(ELF_R_TYPE(rel->r_info)),
@@ -636,8 +738,140 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 	}
 }
 
-static int do_reloc(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
-		    const char *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;
+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;
+	}
+}
+
+/*
+ * 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_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:
+	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;
+
+			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 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);
@@ -779,9 +1013,18 @@ 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 (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+		do_reloc = do_reloc64;
+	else if (!use_real_mode)
+		do_reloc = do_reloc32;
+	else
+		do_reloc = do_reloc_real;
 
 	/* Collect up the relocations */
-	walk_relocs(use_real_mode ? do_reloc_real : do_reloc);
+	walk_relocs(do_reloc);
 
 	if (relocs16.count && !use_real_mode)
 		die("Segment relocations found but --realmode not specified\n");
@@ -789,6 +1032,7 @@ static void emit_relocs(int as_text, int use_real_mode)
 	/* Order the relocations for more efficient processing */
 	sort_relocs(&relocs16);
 	sort_relocs(&relocs32);
+	sort_relocs(&relocs64);
 
 	/* Print the relocations */
 	if (as_text) {
@@ -809,6 +1053,15 @@ static void emit_relocs(int as_text, int use_real_mode)
 		for (i = 0; i < relocs32.count; i++)
 			write_reloc(relocs32.offset[i], stdout);
 	} else {
+		if (ehdr.e_ident[EI_CLASS] == ELFCLASS64) {
+			/* 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);
 
@@ -876,6 +1129,8 @@ int main(int argc, char **argv)
 	read_strtabs(fp);
 	read_symtabs(fp);
 	read_relocs(fp);
+	if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+		percpu_init();
 	if (show_absolute_syms) {
 		print_absolute_symbols();
 		goto out;
-- 
cgit v1.2.3


From 17c961f7702ff6037b66bb2e5f3ddd58de4ce7e5 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 12 Apr 2013 13:13:45 -0700
Subject: x86, relocs: Build separate 32/64-bit tools

Since the ELF structures and access macros change size based on 32 vs
64 bits, build a separate 32-bit relocs tool (for handling realmode
and 32-bit relocations), and a 64-bit relocs tool (for handling 64-bit
kernel relocations).

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1365797627-20874-5-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/boot/compressed/Makefile |  2 +-
 arch/x86/realmode/rm/Makefile     |  2 +-
 arch/x86/tools/.gitignore         |  3 ++-
 arch/x86/tools/Makefile           | 20 ++++++++++++++++++--
 4 files changed, 22 insertions(+), 5 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 5ef205c5f37b..0dac17528099 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -44,7 +44,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE
 
 targets += $(patsubst $(obj)/%,%,$(VMLINUX_OBJS)) 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 88692871823f..2b1e4294b8b9 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 be0ed065249b..2b45d5f063ba 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 bae601f900ef..a8cb70c6b8a1 100644
--- a/arch/x86/tools/Makefile
+++ b/arch/x86/tools/Makefile
@@ -37,6 +37,22 @@ $(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
 
+HOSTCFLAGS_relocs_32.o += -DELF_BITS=32
+HOSTCFLAGS_relocs_64.o += -DELF_BITS=64
+
+quiet_cmd_cp_reloc = GEN     $@
+      cmd_cp_reloc = cp $< $@
+
+$(obj)/relocs_%.c: $(srctree)/arch/x86/tools/relocs.c
+	$(call cmd,cp_reloc)
+
 HOST_EXTRACFLAGS += -I$(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_32: $(obj)/relocs_32
+relocs_64: $(obj)/relocs_64
-- 
cgit v1.2.3


From c889ba801dc3b3a0155fa77d567f2c3a6097de1c Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@linux.intel.com>
Date: Tue, 16 Apr 2013 16:02:58 -0700
Subject: x86, relocs: Refactor the relocs tool to merge 32- and 64-bit ELF

Refactor the relocs tool so that the same tool can handle 32- and
64-bit ELF.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1365797627-20874-5-git-send-email-keescook@chromium.org
---
 arch/x86/boot/compressed/Makefile |   2 +-
 arch/x86/realmode/rm/Makefile     |   2 +-
 arch/x86/tools/.gitignore         |   3 +-
 arch/x86/tools/Makefile           |  21 +----
 arch/x86/tools/relocs.c           | 162 ++++++++------------------------------
 arch/x86/tools/relocs.h           |  36 +++++++++
 arch/x86/tools/relocs_32.c        |  17 ++++
 arch/x86/tools/relocs_64.c        |  17 ++++
 arch/x86/tools/relocs_common.c    |  76 ++++++++++++++++++
 9 files changed, 183 insertions(+), 153 deletions(-)
 create mode 100644 arch/x86/tools/relocs.h
 create mode 100644 arch/x86/tools/relocs_32.c
 create mode 100644 arch/x86/tools/relocs_64.c
 create mode 100644 arch/x86/tools/relocs_common.c

(limited to 'arch/x86')

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 0dac17528099..5ef205c5f37b 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -44,7 +44,7 @@ $(obj)/vmlinux.bin: vmlinux FORCE
 
 targets += $(patsubst $(obj)/%,%,$(VMLINUX_OBJS)) vmlinux.bin.all vmlinux.relocs
 
-CMD_RELOCS = arch/x86/tools/relocs_$(BITS)
+CMD_RELOCS = arch/x86/tools/relocs
 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 2b1e4294b8b9..88692871823f 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_32 --realmode $< > $@
+      cmd_relocs = arch/x86/tools/relocs --realmode $< > $@
 
 targets += realmode.relocs
 $(obj)/realmode.relocs: $(obj)/realmode.elf FORCE
diff --git a/arch/x86/tools/.gitignore b/arch/x86/tools/.gitignore
index 2b45d5f063ba..be0ed065249b 100644
--- a/arch/x86/tools/.gitignore
+++ b/arch/x86/tools/.gitignore
@@ -1,2 +1 @@
-relocs_32*
-relocs_64*
+relocs
diff --git a/arch/x86/tools/Makefile b/arch/x86/tools/Makefile
index a8cb70c6b8a1..e8120346903b 100644
--- a/arch/x86/tools/Makefile
+++ b/arch/x86/tools/Makefile
@@ -37,22 +37,7 @@ $(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
 
-HOSTCFLAGS_relocs_32.o += -DELF_BITS=32
-HOSTCFLAGS_relocs_64.o += -DELF_BITS=64
-
-quiet_cmd_cp_reloc = GEN     $@
-      cmd_cp_reloc = cp $< $@
-
-$(obj)/relocs_%.c: $(srctree)/arch/x86/tools/relocs.c
-	$(call cmd,cp_reloc)
-
 HOST_EXTRACFLAGS += -I$(srctree)/tools/include
-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_32: $(obj)/relocs_32
-relocs_64: $(obj)/relocs_64
+hostprogs-y	+= relocs
+relocs-objs     := relocs_32.o relocs_64.o relocs_common.o
+relocs: $(obj)/relocs
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 1f7ff3d11a05..590be1090892 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -1,63 +1,15 @@
-#include <stdio.h>
-#include <stdarg.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <inttypes.h>
-#include <string.h>
-#include <errno.h>
-#include <unistd.h>
-#include <elf.h>
-#include <byteswap.h>
-#define USE_BSD
-#include <endian.h>
-#include <regex.h>
-#include <tools/le_byteshift.h>
+/* 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
 
-#ifndef ELF_BITS
-#define ELF_BITS		32
-#endif
-
-#if (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_MACHINE		EM_386
-#define ELF_MACHINE_NAME	"i386"
-#define SHT_REL_TYPE		SHT_REL
-#define Elf_Rel			ElfW(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 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 void die(char *fmt, ...);
-
-#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 static Elf_Ehdr ehdr;
 
 struct relocs {
@@ -79,14 +31,6 @@ struct section {
 };
 static struct section *secs;
 
-enum symtype {
-	S_ABS,
-	S_REL,
-	S_SEG,
-	S_LIN,
-	S_NSYMTYPES
-};
-
 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 /*
  * Following symbols have been audited. There values are constant and do
@@ -98,7 +42,7 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"^(xen_irq_disable_direct_reloc$|"
 	"xen_save_fl_direct_reloc$|"
 	"VDSO|"
-#if (ELF_BITS == 64)
+#if ELF_BITS == 64
 	"__vvar_page|"
 #endif
 	"__crc_)",
@@ -124,7 +68,7 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"__end_rodata|"
 	"__initramfs_start|"
 	"(jiffies|jiffies_64)|"
-#if (ELF_BITS == 64)
+#if ELF_BITS == 64
 	"__per_cpu_load|"
 	"init_per_cpu__.*|"
 	"__end_rodata_hpage_align|"
@@ -189,15 +133,6 @@ static void regex_init(int use_real_mode)
         }
 }
 
-static void die(char *fmt, ...)
-{
-	va_list ap;
-	va_start(ap, fmt);
-	vfprintf(stderr, fmt, ap);
-	va_end(ap);
-	exit(1);
-}
-
 static const char *sym_type(unsigned type)
 {
 	static const char *type_name[] = {
@@ -255,7 +190,7 @@ static const char *rel_type(unsigned type)
 {
 	static const char *type_name[] = {
 #define REL_TYPE(X) [X] = #X
-#if (ELF_BITS == 64)
+#if ELF_BITS == 64
 		REL_TYPE(R_X86_64_NONE),
 		REL_TYPE(R_X86_64_64),
 		REL_TYPE(R_X86_64_PC32),
@@ -380,7 +315,7 @@ static uint32_t elf32_to_cpu(uint32_t 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)
+#if ELF_BITS == 64
 static uint64_t elf64_to_cpu(uint64_t val)
 {
         return le64_to_cpu(val);
@@ -582,7 +517,7 @@ static void print_absolute_symbols(void)
 	int i;
 	const char *format;
 
-	if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+	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";
@@ -622,7 +557,7 @@ static void print_absolute_relocs(void)
 	int i, printed = 0;
 	const char *format;
 
-	if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+	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";
@@ -785,6 +720,8 @@ static void percpu_init(void)
 	}
 }
 
+#if ELF_BITS == 64
+
 /*
  * Check to see if a symbol lies in the .data..percpu section.
  * For some as yet not understood reason the "__init_begin"
@@ -798,6 +735,7 @@ static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
 		strcmp(symname, "__init_begin");
 }
 
+
 static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 		      const char *symname)
 {
@@ -869,6 +807,7 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 	return 0;
 }
 
+#else
 
 static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 		      const char *symname)
@@ -984,6 +923,8 @@ static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 	return 0;
 }
 
+#endif
+
 static int cmp_relocs(const void *va, const void *vb)
 {
 	const uint32_t *a, *b;
@@ -1016,12 +957,17 @@ static void emit_relocs(int as_text, int use_real_mode)
 	int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 			const char *symname);
 
-	if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+#if ELF_BITS == 64
+	if (!use_real_mode)
 		do_reloc = do_reloc64;
-	else if (!use_real_mode)
+	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);
@@ -1053,7 +999,7 @@ static void emit_relocs(int as_text, int use_real_mode)
 		for (i = 0; i < relocs32.count; i++)
 			write_reloc(relocs32.offset[i], stdout);
 	} else {
-		if (ehdr.e_ident[EI_CLASS] == ELFCLASS64) {
+		if (ELF_BITS == 64) {
 			/* Print a stop */
 			write_reloc(0, stdout);
 
@@ -1071,76 +1017,30 @@ static void emit_relocs(int as_text, int use_real_mode)
 	}
 }
 
-static void usage(void)
-{
-	die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
-}
+#if ELF_BITS == 64
+# define process process_64
+#else
+# define process process_32
+#endif
 
-int main(int argc, char **argv)
+void process(FILE *fp, int use_real_mode, int as_text,
+	     int show_absolute_syms, int show_absolute_relocs)
 {
-	int show_absolute_syms, show_absolute_relocs;
-	int as_text, use_real_mode;
-	const char *fname;
-	FILE *fp;
-	int i;
-
-	show_absolute_syms = 0;
-	show_absolute_relocs = 0;
-	as_text = 0;
-	use_real_mode = 0;
-	fname = NULL;
-	for (i = 1; i < argc; i++) {
-		char *arg = argv[i];
-		if (*arg == '-') {
-			if (strcmp(arg, "--abs-syms") == 0) {
-				show_absolute_syms = 1;
-				continue;
-			}
-			if (strcmp(arg, "--abs-relocs") == 0) {
-				show_absolute_relocs = 1;
-				continue;
-			}
-			if (strcmp(arg, "--text") == 0) {
-				as_text = 1;
-				continue;
-			}
-			if (strcmp(arg, "--realmode") == 0) {
-				use_real_mode = 1;
-				continue;
-			}
-		}
-		else if (!fname) {
-			fname = arg;
-			continue;
-		}
-		usage();
-	}
-	if (!fname) {
-		usage();
-	}
 	regex_init(use_real_mode);
-	fp = fopen(fname, "r");
-	if (!fp) {
-		die("Cannot open %s: %s\n",
-			fname, strerror(errno));
-	}
 	read_ehdr(fp);
 	read_shdrs(fp);
 	read_strtabs(fp);
 	read_symtabs(fp);
 	read_relocs(fp);
-	if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
+	if (ELF_BITS == 64)
 		percpu_init();
 	if (show_absolute_syms) {
 		print_absolute_symbols();
-		goto out;
+		return;
 	}
 	if (show_absolute_relocs) {
 		print_absolute_relocs();
-		goto out;
+		return;
 	}
 	emit_relocs(as_text, use_real_mode);
-out:
-	fclose(fp);
-	return 0;
 }
diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
new file mode 100644
index 000000000000..07cdb1eca4fa
--- /dev/null
+++ b/arch/x86/tools/relocs.h
@@ -0,0 +1,36 @@
+#ifndef RELOCS_H
+#define RELOCS_H
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <elf.h>
+#include <byteswap.h>
+#define USE_BSD
+#include <endian.h>
+#include <regex.h>
+#include <tools/le_byteshift.h>
+
+void die(char *fmt, ...);
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+enum symtype {
+	S_ABS,
+	S_REL,
+	S_SEG,
+	S_LIN,
+	S_NSYMTYPES
+};
+
+void process_32(FILE *fp, int use_real_mode, int as_text,
+		int show_absolute_syms, int show_absolute_relocs);
+void process_64(FILE *fp, int use_real_mode, int as_text,
+		int show_absolute_syms, int show_absolute_relocs);
+
+#endif /* RELOCS_H */
diff --git a/arch/x86/tools/relocs_32.c b/arch/x86/tools/relocs_32.c
new file mode 100644
index 000000000000..b2ade2bb4162
--- /dev/null
+++ b/arch/x86/tools/relocs_32.c
@@ -0,0 +1,17 @@
+#include "relocs.h"
+
+#define ELF_BITS 32
+
+#define ELF_MACHINE		EM_386
+#define ELF_MACHINE_NAME	"i386"
+#define SHT_REL_TYPE		SHT_REL
+#define Elf_Rel			ElfW(Rel)
+
+#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)
+
+#include "relocs.c"
diff --git a/arch/x86/tools/relocs_64.c b/arch/x86/tools/relocs_64.c
new file mode 100644
index 000000000000..56b61b743c4c
--- /dev/null
+++ b/arch/x86/tools/relocs_64.c
@@ -0,0 +1,17 @@
+#include "relocs.h"
+
+#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
+
+#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)
+
+#include "relocs.c"
diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
new file mode 100644
index 000000000000..44d396823a53
--- /dev/null
+++ b/arch/x86/tools/relocs_common.c
@@ -0,0 +1,76 @@
+#include "relocs.h"
+
+void die(char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	exit(1);
+}
+
+static void usage(void)
+{
+	die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
+}
+
+int main(int argc, char **argv)
+{
+	int show_absolute_syms, show_absolute_relocs;
+	int as_text, use_real_mode;
+	const char *fname;
+	FILE *fp;
+	int i;
+	unsigned char e_ident[EI_NIDENT];
+
+	show_absolute_syms = 0;
+	show_absolute_relocs = 0;
+	as_text = 0;
+	use_real_mode = 0;
+	fname = NULL;
+	for (i = 1; i < argc; i++) {
+		char *arg = argv[i];
+		if (*arg == '-') {
+			if (strcmp(arg, "--abs-syms") == 0) {
+				show_absolute_syms = 1;
+				continue;
+			}
+			if (strcmp(arg, "--abs-relocs") == 0) {
+				show_absolute_relocs = 1;
+				continue;
+			}
+			if (strcmp(arg, "--text") == 0) {
+				as_text = 1;
+				continue;
+			}
+			if (strcmp(arg, "--realmode") == 0) {
+				use_real_mode = 1;
+				continue;
+			}
+		}
+		else if (!fname) {
+			fname = arg;
+			continue;
+		}
+		usage();
+	}
+	if (!fname) {
+		usage();
+	}
+	fp = fopen(fname, "r");
+	if (!fp) {
+		die("Cannot open %s: %s\n", fname, strerror(errno));
+	}
+	if (fread(&e_ident, 1, EI_NIDENT, fp) != EI_NIDENT) {
+		die("Cannot read %s: %s", fname, strerror(errno));
+	}
+	rewind(fp);
+	if (e_ident[EI_CLASS] == ELFCLASS64)
+		process_64(fp, use_real_mode, as_text,
+			   show_absolute_syms, show_absolute_relocs);
+	else
+		process_32(fp, use_real_mode, as_text,
+			   show_absolute_syms, show_absolute_relocs);
+	fclose(fp);
+	return 0;
+}
-- 
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