Commit 01c7cd0e authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perparatory x86 kasrl changes from Ingo Molnar:
 "This contains changes from the ongoing KASLR work, by Kees Cook.

  The main changes are the use of a read-only IDT on x86 (which
  decouples the userspace visible virtual IDT address from the physical
  address), and a rework of ELF relocation support, in preparation of
  random, boot-time kernel image relocation."

* 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, relocs: Refactor the relocs tool to merge 32- and 64-bit ELF
  x86, relocs: Build separate 32/64-bit tools
  x86, relocs: Add 64-bit ELF support to relocs tool
  x86, relocs: Consolidate processing logic
  x86, relocs: Generalize ELF structure names
  x86: Use a read-only IDT alias on all CPUs
parents 39b2f865 c889ba80
......@@ -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
......
......@@ -176,20 +176,6 @@ 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() ? */
......@@ -218,8 +204,7 @@ 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.
*/
clear_cpu_bug(c, X86_BUG_F00F);
if (!paravirt_enabled() && c->x86 == 5) {
......@@ -227,7 +212,6 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
set_cpu_bug(c, X86_BUG_F00F);
if (!f00f_workaround_enabled) {
trap_init_f00f_bug();
printk(KERN_NOTICE "Intel Pentium with F0 0F bug - workaround enabled.\n");
f00f_workaround_enabled = 1;
}
......
......@@ -56,6 +56,7 @@
#include <asm/i387.h>
#include <asm/fpu-internal.h>
#include <asm/mce.h>
#include <asm/fixmap.h>
#include <asm/mach_traps.h>
#ifdef CONFIG_X86_64
......@@ -768,6 +769,14 @@ 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:
*/
......
......@@ -39,4 +39,5 @@ $(obj)/insn_sanity.o: $(srctree)/arch/x86/lib/insn.c $(srctree)/arch/x86/lib/ina
HOST_EXTRACFLAGS += -I$(srctree)/tools/include
hostprogs-y += relocs
relocs-objs := relocs_32.o relocs_64.o relocs_common.o
relocs: $(obj)/relocs
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <elf.h>
#include <byteswap.h>
#define USE_BSD
#include <endian.h>
#include <regex.h>
#include <tools/le_byteshift.h>
static void die(char *fmt, ...);
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
static Elf32_Ehdr ehdr;
static unsigned long reloc_count, reloc_idx;
static unsigned long *relocs;
static unsigned long reloc16_count, reloc16_idx;
static unsigned long *relocs16;
/* This is included from relocs_32/64.c */
#define ElfW(type) _ElfW(ELF_BITS, type)
#define _ElfW(bits, type) __ElfW(bits, type)
#define __ElfW(bits, type) Elf##bits##_##type
#define Elf_Addr ElfW(Addr)
#define Elf_Ehdr ElfW(Ehdr)
#define Elf_Phdr ElfW(Phdr)
#define Elf_Shdr ElfW(Shdr)
#define Elf_Sym ElfW(Sym)
static Elf_Ehdr ehdr;
struct relocs {
uint32_t *offset;
unsigned long count;
unsigned long size;
};
static struct relocs relocs16;
static struct relocs relocs32;
static struct relocs relocs64;
struct section {
Elf32_Shdr shdr;
Elf_Shdr shdr;
struct section *link;
Elf32_Sym *symtab;
Elf32_Rel *reltab;
Elf_Sym *symtab;
Elf_Rel *reltab;
char *strtab;
};
static struct section *secs;
enum symtype {
S_ABS,
S_REL,
S_SEG,
S_LIN,
S_NSYMTYPES
};
static const char * const sym_regex_kernel[S_NSYMTYPES] = {
/*
* Following symbols have been audited. There values are constant and do
......@@ -49,6 +42,9 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
"^(xen_irq_disable_direct_reloc$|"
"xen_save_fl_direct_reloc$|"
"VDSO|"
#if ELF_BITS == 64
"__vvar_page|"
#endif
"__crc_)",
/*
......@@ -72,6 +68,11 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
"__end_rodata|"
"__initramfs_start|"
"(jiffies|jiffies_64)|"
#if ELF_BITS == 64
"__per_cpu_load|"
"init_per_cpu__.*|"
"__end_rodata_hpage_align|"
#endif
"_end)$"
};
......@@ -132,15 +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[] = {
......@@ -198,6 +190,24 @@ 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),
......@@ -213,6 +223,7 @@ 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 +251,7 @@ 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>";
......@@ -253,15 +264,42 @@ static const char *sym_name(const char *sym_strtab, Elf32_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)
......@@ -274,6 +312,23 @@ 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) {
......@@ -283,8 +338,8 @@ 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 +348,36 @@ 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 +388,7 @@ 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 +404,16 @@ 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 +467,12 @@ 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 +483,7 @@ 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 +500,13 @@ 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
}
}
}
......@@ -457,6 +515,13 @@ static void read_relocs(FILE *fp)
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++) {
......@@ -468,19 +533,19 @@ 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);
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(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);
}
}
......@@ -490,14 +555,20 @@ static void print_absolute_symbols(void)
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;
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 +578,12 @@ 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;
......@@ -542,10 +613,10 @@ 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(ELF32_R_TYPE(rel->r_info)),
rel_type(ELF_R_TYPE(rel->r_info)),
sym->st_value,
name);
}
......@@ -555,19 +626,34 @@ 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 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;
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;
......@@ -577,18 +663,200 @@ 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;
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);
rel = &sec->reltab[j];
sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
r_type = ELF32_R_TYPE(rel->r_info);
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;
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.
* 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;
}
#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;
}
shn_abs = sym->st_shndx == SHN_ABS;
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:
......@@ -596,82 +864,80 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
case R_386_PC16:
case R_386_PC8:
/*
* NONE can be ignored and and PC relative
* relocations don't need to be adjusted.
* NONE can be ignored and PC relative relocations don't
* need to be adjusted.
*/
break;
case R_386_16:
symname = sym_name(sym_strtab, sym);
if (!use_real_mode)
goto bad;
if (shn_abs) {
/*
* Whitelisted absolute symbols do not require
* relocation.
*/
if (is_reloc(S_ABS, symname))
break;
else if (!is_reloc(S_SEG, symname))
goto bad;
if (is_reloc(S_SEG, symname)) {
add_reloc(&relocs16, rel->r_offset);
break;
}
} else {
if (is_reloc(S_LIN, symname))
goto bad;
else
if (!is_reloc(S_LIN, symname))
break;
}
visit(rel, sym);
die("Invalid %s %s relocation: %s\n",
shn_abs ? "absolute" : "relative",
rel_type(r_type), symname);
break;
case R_386_32:
symname = sym_name(sym_strtab, sym);
if (shn_abs) {
/*
* Whitelisted absolute symbols do not require
* relocation.
*/
if (is_reloc(S_ABS, symname))
break;
else if (!is_reloc(S_REL, symname))
goto bad;
if (is_reloc(S_REL, symname)) {
add_reloc(&relocs32, rel->r_offset);
break;
}
} else {
if (use_real_mode &&
!is_reloc(S_LIN, symname))
if (is_reloc(S_LIN, symname))
add_reloc(&relocs32, rel->r_offset);
break;
}
visit(rel, sym);
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;
bad:
symname = sym_name(sym_strtab, sym);
die("Invalid %s %s relocation: %s\n",
shn_abs ? "absolute" : "relative",
rel_type(r_type), symname);
}
}
}
}
static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
{
if (ELF32_R_TYPE(rel->r_info) == R_386_16)
reloc16_count++;
else
reloc_count++;
return 0;
}
static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
{
/* 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;
}
#endif
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];
......@@ -679,33 +945,40 @@ 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;
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
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(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);
sort_relocs(&relocs64);
/* Print the relocations */
if (as_text) {
......@@ -714,114 +987,60 @@ 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]);
}
write_reloc = write32_as_text;
}
printf("\n");
}
else {
if (use_real_mode) {
write32(reloc16_count, stdout);
for (i = 0; i < reloc16_count; i++)
write32(relocs16[i], stdout);
write32(reloc_count, stdout);
write_reloc(relocs16.count, stdout);
for (i = 0; i < relocs16.count; i++)
write_reloc(relocs16.offset[i], stdout);
/* Now print each relocation */
for (i = 0; i < reloc_count; i++)
write32(relocs[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 */
write32(0, stdout);
write_reloc(0, stdout);
/* Now print each relocation */
for (i = 0; i < reloc_count; i++) {
write32(relocs[i], stdout);
}
for (i = 0; i < relocs64.count; i++)
write_reloc(relocs64.offset[i], stdout);
}
/* 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)
{
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 (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;
}
#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 */
#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"
#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"
#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;
}
......@@ -2043,9 +2043,7 @@ 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:
......
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