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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-23 17:44:35 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-23 17:44:35 (GMT)
commit269af9a1a08d368b46d72e74126564d04c354f7e (patch)
treef0f2a8dd54075edebbb728602822e2b7378588d0 /scripts
parent8ca038dc10eec80f280d9d483f1835ac2763a787 (diff)
parent8b5ad472991796b2347464922c72de2ca5a028f3 (diff)
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Merge branch 'x86-extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull exception table generation updates from Ingo Molnar: "The biggest change here is to allow the build-time sorting of the exception table, to speed up booting. This is achieved by the architecture enabling BUILDTIME_EXTABLE_SORT. This option is enabled for x86 and MIPS currently. On x86 a number of fixes and changes were needed to allow build-time sorting of the exception table, in particular a relocation invariant exception table format was needed. This required the abstracting out of exception table protocol and the removal of 20 years of accumulated assumptions about the x86 exception table format. While at it, this tree also cleans up various other aspects of exception handling, such as early(er) exception handling for rdmsr_safe() et al. All in one, as the result of these changes the x86 exception code is now pretty nice and modern. As an added bonus any regressions in this code will be early and violent crashes, so if you see any of those, you'll know whom to blame!" Fix up trivial conflicts in arch/{mips,x86}/Kconfig files due to nearby modifications of other core architecture options. * 'x86-extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits) Revert "x86, extable: Disable presorted exception table for now" scripts/sortextable: Handle relative entries, and other cleanups x86, extable: Switch to relative exception table entries x86, extable: Disable presorted exception table for now x86, extable: Add _ASM_EXTABLE_EX() macro x86, extable: Remove open-coded exception table entries in arch/x86/ia32/ia32entry.S x86, extable: Remove open-coded exception table entries in arch/x86/include/asm/xsave.h x86, extable: Remove open-coded exception table entries in arch/x86/include/asm/kvm_host.h x86, extable: Remove the now-unused __ASM_EX_SEC macros x86, extable: Remove open-coded exception table entries in arch/x86/xen/xen-asm_32.S x86, extable: Remove open-coded exception table entries in arch/x86/um/checksum_32.S x86, extable: Remove open-coded exception table entries in arch/x86/lib/usercopy_32.c x86, extable: Remove open-coded exception table entries in arch/x86/lib/putuser.S x86, extable: Remove open-coded exception table entries in arch/x86/lib/getuser.S x86, extable: Remove open-coded exception table entries in arch/x86/lib/csum-copy_64.S x86, extable: Remove open-coded exception table entries in arch/x86/lib/copy_user_nocache_64.S x86, extable: Remove open-coded exception table entries in arch/x86/lib/copy_user_64.S x86, extable: Remove open-coded exception table entries in arch/x86/lib/checksum_32.S x86, extable: Remove open-coded exception table entries in arch/x86/kernel/test_rodata.c x86, extable: Remove open-coded exception table entries in arch/x86/kernel/entry_64.S ...
Diffstat (limited to 'scripts')
-rw-r--r--scripts/.gitignore1
-rw-r--r--scripts/Makefile3
-rw-r--r--scripts/sortextable.c322
-rw-r--r--scripts/sortextable.h191
4 files changed, 517 insertions, 0 deletions
diff --git a/scripts/.gitignore b/scripts/.gitignore
index 105b21f..65f362d 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -9,3 +9,4 @@ unifdef
ihex2fw
recordmcount
docproc
+sortextable
diff --git a/scripts/Makefile b/scripts/Makefile
index 3626666..a55b006 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -15,6 +15,9 @@ hostprogs-$(CONFIG_LOGO) += pnmtologo
hostprogs-$(CONFIG_VT) += conmakehash
hostprogs-$(CONFIG_IKCONFIG) += bin2c
hostprogs-$(BUILD_C_RECORDMCOUNT) += recordmcount
+hostprogs-$(CONFIG_BUILDTIME_EXTABLE_SORT) += sortextable
+
+HOSTCFLAGS_sortextable.o = -I$(srctree)/tools/include
always := $(hostprogs-y) $(hostprogs-m)
diff --git a/scripts/sortextable.c b/scripts/sortextable.c
new file mode 100644
index 0000000..1ca9ceb
--- /dev/null
+++ b/scripts/sortextable.c
@@ -0,0 +1,322 @@
+/*
+ * sortextable.c: Sort the kernel's exception table
+ *
+ * Copyright 2011 - 2012 Cavium, Inc.
+ *
+ * Based on code taken from recortmcount.c which is:
+ *
+ * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
+ * Licensed under the GNU General Public License, version 2 (GPLv2).
+ *
+ * Restructured to fit Linux format, as well as other updates:
+ * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
+ */
+
+/*
+ * Strategy: alter the vmlinux file in-place.
+ */
+
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <getopt.h>
+#include <elf.h>
+#include <fcntl.h>
+#include <setjmp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <tools/be_byteshift.h>
+#include <tools/le_byteshift.h>
+
+static int fd_map; /* File descriptor for file being modified. */
+static int mmap_failed; /* Boolean flag. */
+static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
+static struct stat sb; /* Remember .st_size, etc. */
+static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
+
+/* setjmp() return values */
+enum {
+ SJ_SETJMP = 0, /* hardwired first return */
+ SJ_FAIL,
+ SJ_SUCCEED
+};
+
+/* Per-file resource cleanup when multiple files. */
+static void
+cleanup(void)
+{
+ if (!mmap_failed)
+ munmap(ehdr_curr, sb.st_size);
+ close(fd_map);
+}
+
+static void __attribute__((noreturn))
+fail_file(void)
+{
+ cleanup();
+ longjmp(jmpenv, SJ_FAIL);
+}
+
+static void __attribute__((noreturn))
+succeed_file(void)
+{
+ cleanup();
+ longjmp(jmpenv, SJ_SUCCEED);
+}
+
+
+/*
+ * Get the whole file as a programming convenience in order to avoid
+ * malloc+lseek+read+free of many pieces. If successful, then mmap
+ * avoids copying unused pieces; else just read the whole file.
+ * Open for both read and write.
+ */
+static void *mmap_file(char const *fname)
+{
+ void *addr;
+
+ fd_map = open(fname, O_RDWR);
+ if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
+ perror(fname);
+ fail_file();
+ }
+ if (!S_ISREG(sb.st_mode)) {
+ fprintf(stderr, "not a regular file: %s\n", fname);
+ fail_file();
+ }
+ addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED,
+ fd_map, 0);
+ if (addr == MAP_FAILED) {
+ mmap_failed = 1;
+ fprintf(stderr, "Could not mmap file: %s\n", fname);
+ fail_file();
+ }
+ return addr;
+}
+
+static uint64_t r8be(const uint64_t *x)
+{
+ return get_unaligned_be64(x);
+}
+static uint32_t rbe(const uint32_t *x)
+{
+ return get_unaligned_be32(x);
+}
+static uint16_t r2be(const uint16_t *x)
+{
+ return get_unaligned_be16(x);
+}
+static uint64_t r8le(const uint64_t *x)
+{
+ return get_unaligned_le64(x);
+}
+static uint32_t rle(const uint32_t *x)
+{
+ return get_unaligned_le32(x);
+}
+static uint16_t r2le(const uint16_t *x)
+{
+ return get_unaligned_le16(x);
+}
+
+static void w8be(uint64_t val, uint64_t *x)
+{
+ put_unaligned_be64(val, x);
+}
+static void wbe(uint32_t val, uint32_t *x)
+{
+ put_unaligned_be32(val, x);
+}
+static void w2be(uint16_t val, uint16_t *x)
+{
+ put_unaligned_be16(val, x);
+}
+static void w8le(uint64_t val, uint64_t *x)
+{
+ put_unaligned_le64(val, x);
+}
+static void wle(uint32_t val, uint32_t *x)
+{
+ put_unaligned_le32(val, x);
+}
+static void w2le(uint16_t val, uint16_t *x)
+{
+ put_unaligned_le16(val, x);
+}
+
+static uint64_t (*r8)(const uint64_t *);
+static uint32_t (*r)(const uint32_t *);
+static uint16_t (*r2)(const uint16_t *);
+static void (*w8)(uint64_t, uint64_t *);
+static void (*w)(uint32_t, uint32_t *);
+static void (*w2)(uint16_t, uint16_t *);
+
+typedef void (*table_sort_t)(char *, int);
+
+/* 32 bit and 64 bit are very similar */
+#include "sortextable.h"
+#define SORTEXTABLE_64
+#include "sortextable.h"
+
+static int compare_x86_table(const void *a, const void *b)
+{
+ int32_t av = (int32_t)r(a);
+ int32_t bv = (int32_t)r(b);
+
+ if (av < bv)
+ return -1;
+ if (av > bv)
+ return 1;
+ return 0;
+}
+
+static void sort_x86_table(char *extab_image, int image_size)
+{
+ int i;
+
+ /*
+ * Do the same thing the runtime sort does, first normalize to
+ * being relative to the start of the section.
+ */
+ i = 0;
+ while (i < image_size) {
+ uint32_t *loc = (uint32_t *)(extab_image + i);
+ w(r(loc) + i, loc);
+ i += 4;
+ }
+
+ qsort(extab_image, image_size / 8, 8, compare_x86_table);
+
+ /* Now denormalize. */
+ i = 0;
+ while (i < image_size) {
+ uint32_t *loc = (uint32_t *)(extab_image + i);
+ w(r(loc) - i, loc);
+ i += 4;
+ }
+}
+
+static void
+do_file(char const *const fname)
+{
+ table_sort_t custom_sort;
+ Elf32_Ehdr *ehdr = mmap_file(fname);
+
+ ehdr_curr = ehdr;
+ switch (ehdr->e_ident[EI_DATA]) {
+ default:
+ fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
+ ehdr->e_ident[EI_DATA], fname);
+ fail_file();
+ break;
+ case ELFDATA2LSB:
+ r = rle;
+ r2 = r2le;
+ r8 = r8le;
+ w = wle;
+ w2 = w2le;
+ w8 = w8le;
+ break;
+ case ELFDATA2MSB:
+ r = rbe;
+ r2 = r2be;
+ r8 = r8be;
+ w = wbe;
+ w2 = w2be;
+ w8 = w8be;
+ break;
+ } /* end switch */
+ if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
+ || r2(&ehdr->e_type) != ET_EXEC
+ || ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
+ fprintf(stderr, "unrecognized ET_EXEC file %s\n", fname);
+ fail_file();
+ }
+
+ custom_sort = NULL;
+ switch (r2(&ehdr->e_machine)) {
+ default:
+ fprintf(stderr, "unrecognized e_machine %d %s\n",
+ r2(&ehdr->e_machine), fname);
+ fail_file();
+ break;
+ case EM_386:
+ case EM_X86_64:
+ custom_sort = sort_x86_table;
+ break;
+ case EM_MIPS:
+ break;
+ } /* end switch */
+
+ switch (ehdr->e_ident[EI_CLASS]) {
+ default:
+ fprintf(stderr, "unrecognized ELF class %d %s\n",
+ ehdr->e_ident[EI_CLASS], fname);
+ fail_file();
+ break;
+ case ELFCLASS32:
+ if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
+ || r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
+ fprintf(stderr,
+ "unrecognized ET_EXEC file: %s\n", fname);
+ fail_file();
+ }
+ do32(ehdr, fname, custom_sort);
+ break;
+ case ELFCLASS64: {
+ Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
+ if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
+ || r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
+ fprintf(stderr,
+ "unrecognized ET_EXEC file: %s\n", fname);
+ fail_file();
+ }
+ do64(ghdr, fname, custom_sort);
+ break;
+ }
+ } /* end switch */
+
+ cleanup();
+}
+
+int
+main(int argc, char *argv[])
+{
+ int n_error = 0; /* gcc-4.3.0 false positive complaint */
+ int i;
+
+ if (argc < 2) {
+ fprintf(stderr, "usage: sortextable vmlinux...\n");
+ return 0;
+ }
+
+ /* Process each file in turn, allowing deep failure. */
+ for (i = 1; i < argc; i++) {
+ char *file = argv[i];
+ int const sjval = setjmp(jmpenv);
+
+ switch (sjval) {
+ default:
+ fprintf(stderr, "internal error: %s\n", file);
+ exit(1);
+ break;
+ case SJ_SETJMP: /* normal sequence */
+ /* Avoid problems if early cleanup() */
+ fd_map = -1;
+ ehdr_curr = NULL;
+ mmap_failed = 1;
+ do_file(file);
+ break;
+ case SJ_FAIL: /* error in do_file or below */
+ ++n_error;
+ break;
+ case SJ_SUCCEED: /* premature success */
+ /* do nothing */
+ break;
+ } /* end switch */
+ }
+ return !!n_error;
+}
diff --git a/scripts/sortextable.h b/scripts/sortextable.h
new file mode 100644
index 0000000..e4fd45b
--- /dev/null
+++ b/scripts/sortextable.h
@@ -0,0 +1,191 @@
+/*
+ * sortextable.h
+ *
+ * Copyright 2011 - 2012 Cavium, Inc.
+ *
+ * Some of this code was taken out of recordmcount.h written by:
+ *
+ * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
+ * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
+ *
+ *
+ * Licensed under the GNU General Public License, version 2 (GPLv2).
+ */
+
+#undef extable_ent_size
+#undef compare_extable
+#undef do_func
+#undef Elf_Addr
+#undef Elf_Ehdr
+#undef Elf_Shdr
+#undef Elf_Rel
+#undef Elf_Rela
+#undef Elf_Sym
+#undef ELF_R_SYM
+#undef Elf_r_sym
+#undef ELF_R_INFO
+#undef Elf_r_info
+#undef ELF_ST_BIND
+#undef ELF_ST_TYPE
+#undef fn_ELF_R_SYM
+#undef fn_ELF_R_INFO
+#undef uint_t
+#undef _r
+#undef _w
+
+#ifdef SORTEXTABLE_64
+# define extable_ent_size 16
+# define compare_extable compare_extable_64
+# define do_func do64
+# define Elf_Addr Elf64_Addr
+# define Elf_Ehdr Elf64_Ehdr
+# define Elf_Shdr Elf64_Shdr
+# define Elf_Rel Elf64_Rel
+# define Elf_Rela Elf64_Rela
+# define Elf_Sym Elf64_Sym
+# define ELF_R_SYM ELF64_R_SYM
+# define Elf_r_sym Elf64_r_sym
+# define ELF_R_INFO ELF64_R_INFO
+# define Elf_r_info Elf64_r_info
+# define ELF_ST_BIND ELF64_ST_BIND
+# define ELF_ST_TYPE ELF64_ST_TYPE
+# define fn_ELF_R_SYM fn_ELF64_R_SYM
+# define fn_ELF_R_INFO fn_ELF64_R_INFO
+# define uint_t uint64_t
+# define _r r8
+# define _w w8
+#else
+# define extable_ent_size 8
+# define compare_extable compare_extable_32
+# define do_func do32
+# define Elf_Addr Elf32_Addr
+# define Elf_Ehdr Elf32_Ehdr
+# define Elf_Shdr Elf32_Shdr
+# define Elf_Rel Elf32_Rel
+# define Elf_Rela Elf32_Rela
+# define Elf_Sym Elf32_Sym
+# define ELF_R_SYM ELF32_R_SYM
+# define Elf_r_sym Elf32_r_sym
+# define ELF_R_INFO ELF32_R_INFO
+# define Elf_r_info Elf32_r_info
+# define ELF_ST_BIND ELF32_ST_BIND
+# define ELF_ST_TYPE ELF32_ST_TYPE
+# define fn_ELF_R_SYM fn_ELF32_R_SYM
+# define fn_ELF_R_INFO fn_ELF32_R_INFO
+# define uint_t uint32_t
+# define _r r
+# define _w w
+#endif
+
+static int compare_extable(const void *a, const void *b)
+{
+ Elf_Addr av = _r(a);
+ Elf_Addr bv = _r(b);
+
+ if (av < bv)
+ return -1;
+ if (av > bv)
+ return 1;
+ return 0;
+}
+
+static void
+do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
+{
+ Elf_Shdr *shdr;
+ Elf_Shdr *shstrtab_sec;
+ Elf_Shdr *strtab_sec = NULL;
+ Elf_Shdr *symtab_sec = NULL;
+ Elf_Shdr *extab_sec = NULL;
+ Elf_Sym *sym;
+ Elf_Sym *sort_needed_sym;
+ Elf_Shdr *sort_needed_sec;
+ Elf_Rel *relocs = NULL;
+ int relocs_size;
+ uint32_t *sort_done_location;
+ const char *secstrtab;
+ const char *strtab;
+ char *extab_image;
+ int extab_index = 0;
+ int i;
+ int idx;
+
+ shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
+ shstrtab_sec = shdr + r2(&ehdr->e_shstrndx);
+ secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
+ for (i = 0; i < r2(&ehdr->e_shnum); i++) {
+ idx = r(&shdr[i].sh_name);
+ if (strcmp(secstrtab + idx, "__ex_table") == 0) {
+ extab_sec = shdr + i;
+ extab_index = i;
+ }
+ if ((r(&shdr[i].sh_type) == SHT_REL ||
+ r(&shdr[i].sh_type) == SHT_RELA) &&
+ r(&shdr[i].sh_info) == extab_index) {
+ relocs = (void *)ehdr + _r(&shdr[i].sh_offset);
+ relocs_size = _r(&shdr[i].sh_size);
+ }
+ if (strcmp(secstrtab + idx, ".symtab") == 0)
+ symtab_sec = shdr + i;
+ if (strcmp(secstrtab + idx, ".strtab") == 0)
+ strtab_sec = shdr + i;
+ }
+ if (strtab_sec == NULL) {
+ fprintf(stderr, "no .strtab in file: %s\n", fname);
+ fail_file();
+ }
+ if (symtab_sec == NULL) {
+ fprintf(stderr, "no .symtab in file: %s\n", fname);
+ fail_file();
+ }
+ if (extab_sec == NULL) {
+ fprintf(stderr, "no __ex_table in file: %s\n", fname);
+ fail_file();
+ }
+ strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
+
+ extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
+
+ if (custom_sort) {
+ custom_sort(extab_image, _r(&extab_sec->sh_size));
+ } else {
+ int num_entries = _r(&extab_sec->sh_size) / extable_ent_size;
+ qsort(extab_image, num_entries,
+ extable_ent_size, compare_extable);
+ }
+ /* If there were relocations, we no longer need them. */
+ if (relocs)
+ memset(relocs, 0, relocs_size);
+
+ /* find main_extable_sort_needed */
+ sort_needed_sym = NULL;
+ for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
+ sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
+ sym += i;
+ if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
+ continue;
+ idx = r(&sym->st_name);
+ if (strcmp(strtab + idx, "main_extable_sort_needed") == 0) {
+ sort_needed_sym = sym;
+ break;
+ }
+ }
+ if (sort_needed_sym == NULL) {
+ fprintf(stderr,
+ "no main_extable_sort_needed symbol in file: %s\n",
+ fname);
+ fail_file();
+ }
+ sort_needed_sec = &shdr[r2(&sort_needed_sym->st_shndx)];
+ sort_done_location = (void *)ehdr +
+ _r(&sort_needed_sec->sh_offset) +
+ _r(&sort_needed_sym->st_value) -
+ _r(&sort_needed_sec->sh_addr);
+
+#if 1
+ printf("sort done marker at %lx\n",
+ (unsigned long)((char *)sort_done_location - (char *)ehdr));
+#endif
+ /* We sorted it, clear the flag. */
+ w(0, sort_done_location);
+}