x86, realmode: 16-bit real-mode code support for relocs tool
authorH. Peter Anvin <hpa@linux.intel.com>
Tue, 8 May 2012 18:22:24 +0000 (21:22 +0300)
committerH. Peter Anvin <hpa@linux.intel.com>
Sat, 19 May 2012 02:49:40 +0000 (19:49 -0700)
A new option is added to the relocs tool called '--realmode'.
This option causes the generation of 16-bit segment relocations
and 32-bit linear relocations for the real-mode code. When
the real-mode code is moved to the low-memory during kernel
initialization, these relocation entries can be used to
relocate the code properly.

In the assembly code 16-bit segment relocations must be relative
to the 'real_mode_seg' absolute symbol. Linear relocations must be
relative to a symbol prefixed with 'pa_'.

16-bit segment relocation is used to load cs:ip in 16-bit code.
Linear relocations are used in the 32-bit code for relocatable
data references. They are declared in the linker script of the
real-mode code.

The relocs tool is moved to arch/x86/tools/relocs.c, and added new
target archscripts that can be used to build scripts needed building
an architecture.  be compiled before building the arch/x86 tree.

[ hpa: accelerating this because it detects invalid absolute
  relocations, a serious bug in binutils 2.22.52.0.x which currently
  produces bad kernels. ]

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-2-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>

Makefile
arch/x86/Makefile
arch/x86/boot/compressed/Makefile
arch/x86/boot/compressed/relocs.c [deleted file]
arch/x86/tools/.gitignore [new file with mode: 0644]
arch/x86/tools/Makefile
arch/x86/tools/relocs.c [new file with mode: 0644]
scripts/Makefile

index 48bd1f5..db2bcf3 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -442,7 +442,7 @@ asm-generic:
 
 no-dot-config-targets := clean mrproper distclean \
                         cscope gtags TAGS tags help %docs check% coccicheck \
-                        include/linux/version.h headers_% archheaders \
+                        include/linux/version.h headers_% archheaders archscripts \
                         kernelversion %src-pkg
 
 config-targets := 0
@@ -979,7 +979,7 @@ prepare1: prepare2 include/linux/version.h include/generated/utsrelease.h \
                    include/config/auto.conf
        $(cmd_crmodverdir)
 
-archprepare: archheaders prepare1 scripts_basic
+archprepare: archheaders archscripts prepare1 scripts_basic
 
 prepare0: archprepare FORCE
        $(Q)$(MAKE) $(build)=.
@@ -1049,8 +1049,11 @@ hdr-dst = $(if $(KBUILD_HEADERS), dst=include/asm-$(hdr-arch), dst=include/asm)
 PHONY += archheaders
 archheaders:
 
+PHONY += archscripts
+archscripts:
+
 PHONY += __headers
-__headers: include/linux/version.h scripts_basic asm-generic archheaders FORCE
+__headers: include/linux/version.h scripts_basic asm-generic archheaders archscripts FORCE
        $(Q)$(MAKE) $(build)=scripts build_unifdef
 
 PHONY += headers_install_all
index 41a7237..94e91e4 100644 (file)
@@ -134,6 +134,9 @@ KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
 KBUILD_CFLAGS += $(mflags-y)
 KBUILD_AFLAGS += $(mflags-y)
 
+archscripts:
+       $(Q)$(MAKE) $(build)=arch/x86/tools relocs
+
 ###
 # Syscall table generation
 
index fd55a2f..e398bb5 100644 (file)
@@ -40,13 +40,12 @@ OBJCOPYFLAGS_vmlinux.bin :=  -R .comment -S
 $(obj)/vmlinux.bin: vmlinux FORCE
        $(call if_changed,objcopy)
 
+targets += vmlinux.bin.all vmlinux.relocs
 
-targets += vmlinux.bin.all vmlinux.relocs relocs
-hostprogs-$(CONFIG_X86_NEED_RELOCS) += relocs
-
+CMD_RELOCS = arch/x86/tools/relocs
 quiet_cmd_relocs = RELOCS  $@
-      cmd_relocs = $(obj)/relocs $< > $@;$(obj)/relocs --abs-relocs $<
-$(obj)/vmlinux.relocs: vmlinux $(obj)/relocs FORCE
+      cmd_relocs = $(CMD_RELOCS) $< > $@;$(CMD_RELOCS) --abs-relocs $<
+$(obj)/vmlinux.relocs: vmlinux FORCE
        $(call if_changed,relocs)
 
 vmlinux.bin.all-y := $(obj)/vmlinux.bin
diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c
deleted file mode 100644 (file)
index fb7117a..0000000
+++ /dev/null
@@ -1,678 +0,0 @@
-#include <stdio.h>
-#include <stdarg.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
-#include <errno.h>
-#include <unistd.h>
-#include <elf.h>
-#include <byteswap.h>
-#define USE_BSD
-#include <endian.h>
-#include <regex.h>
-#include <tools/le_byteshift.h>
-
-static void die(char *fmt, ...);
-
-#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
-static Elf32_Ehdr ehdr;
-static unsigned long reloc_count, reloc_idx;
-static unsigned long *relocs;
-
-struct section {
-       Elf32_Shdr     shdr;
-       struct section *link;
-       Elf32_Sym      *symtab;
-       Elf32_Rel      *reltab;
-       char           *strtab;
-};
-static struct section *secs;
-
-/*
- * Following symbols have been audited. There values are constant and do
- * not change if bzImage is loaded at a different physical address than
- * the address for which it has been compiled. Don't warn user about
- * absolute relocations present w.r.t these symbols.
- */
-static const char abs_sym_regex[] =
-       "^(xen_irq_disable_direct_reloc$|"
-       "xen_save_fl_direct_reloc$|"
-       "VDSO|"
-       "__crc_)";
-static regex_t abs_sym_regex_c;
-static int is_abs_reloc(const char *sym_name)
-{
-       return !regexec(&abs_sym_regex_c, sym_name, 0, NULL, 0);
-}
-
-/*
- * These symbols are known to be relative, even if the linker marks them
- * as absolute (typically defined outside any section in the linker script.)
- */
-static const char rel_sym_regex[] =
-       "^_end$";
-static regex_t rel_sym_regex_c;
-static int is_rel_reloc(const char *sym_name)
-{
-       return !regexec(&rel_sym_regex_c, sym_name, 0, NULL, 0);
-}
-
-static void regex_init(void)
-{
-        char errbuf[128];
-        int err;
-       
-        err = regcomp(&abs_sym_regex_c, abs_sym_regex,
-                      REG_EXTENDED|REG_NOSUB);
-        if (err) {
-                regerror(err, &abs_sym_regex_c, errbuf, sizeof errbuf);
-                die("%s", errbuf);
-        }
-
-        err = regcomp(&rel_sym_regex_c, rel_sym_regex,
-                      REG_EXTENDED|REG_NOSUB);
-        if (err) {
-                regerror(err, &rel_sym_regex_c, errbuf, sizeof errbuf);
-                die("%s", errbuf);
-        }
-}
-
-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[] = {
-#define SYM_TYPE(X) [X] = #X
-               SYM_TYPE(STT_NOTYPE),
-               SYM_TYPE(STT_OBJECT),
-               SYM_TYPE(STT_FUNC),
-               SYM_TYPE(STT_SECTION),
-               SYM_TYPE(STT_FILE),
-               SYM_TYPE(STT_COMMON),
-               SYM_TYPE(STT_TLS),
-#undef SYM_TYPE
-       };
-       const char *name = "unknown sym type name";
-       if (type < ARRAY_SIZE(type_name)) {
-               name = type_name[type];
-       }
-       return name;
-}
-
-static const char *sym_bind(unsigned bind)
-{
-       static const char *bind_name[] = {
-#define SYM_BIND(X) [X] = #X
-               SYM_BIND(STB_LOCAL),
-               SYM_BIND(STB_GLOBAL),
-               SYM_BIND(STB_WEAK),
-#undef SYM_BIND
-       };
-       const char *name = "unknown sym bind name";
-       if (bind < ARRAY_SIZE(bind_name)) {
-               name = bind_name[bind];
-       }
-       return name;
-}
-
-static const char *sym_visibility(unsigned visibility)
-{
-       static const char *visibility_name[] = {
-#define SYM_VISIBILITY(X) [X] = #X
-               SYM_VISIBILITY(STV_DEFAULT),
-               SYM_VISIBILITY(STV_INTERNAL),
-               SYM_VISIBILITY(STV_HIDDEN),
-               SYM_VISIBILITY(STV_PROTECTED),
-#undef SYM_VISIBILITY
-       };
-       const char *name = "unknown sym visibility name";
-       if (visibility < ARRAY_SIZE(visibility_name)) {
-               name = visibility_name[visibility];
-       }
-       return name;
-}
-
-static const char *rel_type(unsigned type)
-{
-       static const char *type_name[] = {
-#define REL_TYPE(X) [X] = #X
-               REL_TYPE(R_386_NONE),
-               REL_TYPE(R_386_32),
-               REL_TYPE(R_386_PC32),
-               REL_TYPE(R_386_GOT32),
-               REL_TYPE(R_386_PLT32),
-               REL_TYPE(R_386_COPY),
-               REL_TYPE(R_386_GLOB_DAT),
-               REL_TYPE(R_386_JMP_SLOT),
-               REL_TYPE(R_386_RELATIVE),
-               REL_TYPE(R_386_GOTOFF),
-               REL_TYPE(R_386_GOTPC),
-#undef REL_TYPE
-       };
-       const char *name = "unknown type rel type name";
-       if (type < ARRAY_SIZE(type_name) && type_name[type]) {
-               name = type_name[type];
-       }
-       return name;
-}
-
-static const char *sec_name(unsigned shndx)
-{
-       const char *sec_strtab;
-       const char *name;
-       sec_strtab = secs[ehdr.e_shstrndx].strtab;
-       name = "<noname>";
-       if (shndx < ehdr.e_shnum) {
-               name = sec_strtab + secs[shndx].shdr.sh_name;
-       }
-       else if (shndx == SHN_ABS) {
-               name = "ABSOLUTE";
-       }
-       else if (shndx == SHN_COMMON) {
-               name = "COMMON";
-       }
-       return name;
-}
-
-static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
-{
-       const char *name;
-       name = "<noname>";
-       if (sym->st_name) {
-               name = sym_strtab + sym->st_name;
-       }
-       else {
-               name = sec_name(secs[sym->st_shndx].shdr.sh_name);
-       }
-       return name;
-}
-
-
-
-#if BYTE_ORDER == LITTLE_ENDIAN
-#define le16_to_cpu(val) (val)
-#define le32_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)
-#endif
-
-static uint16_t elf16_to_cpu(uint16_t val)
-{
-       return le16_to_cpu(val);
-}
-
-static uint32_t elf32_to_cpu(uint32_t val)
-{
-       return le32_to_cpu(val);
-}
-
-static void read_ehdr(FILE *fp)
-{
-       if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
-               die("Cannot read ELF header: %s\n",
-                       strerror(errno));
-       }
-       if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
-               die("No ELF magic\n");
-       }
-       if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
-               die("Not a 32 bit executable\n");
-       }
-       if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
-               die("Not a LSB ELF executable\n");
-       }
-       if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
-               die("Unknown ELF version\n");
-       }
-       /* Convert the fields to native endian */
-       ehdr.e_type      = 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);
-
-       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_version != EV_CURRENT) {
-               die("Unknown ELF version\n");
-       }
-       if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
-               die("Bad Elf header size\n");
-       }
-       if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
-               die("Bad program header entry\n");
-       }
-       if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
-               die("Bad section header entry\n");
-       }
-       if (ehdr.e_shstrndx >= ehdr.e_shnum) {
-               die("String table index out of bounds\n");
-       }
-}
-
-static void read_shdrs(FILE *fp)
-{
-       int i;
-       Elf32_Shdr shdr;
-
-       secs = calloc(ehdr.e_shnum, sizeof(struct section));
-       if (!secs) {
-               die("Unable to allocate %d section headers\n",
-                   ehdr.e_shnum);
-       }
-       if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
-               die("Seek to %d failed: %s\n",
-                       ehdr.e_shoff, strerror(errno));
-       }
-       for (i = 0; i < ehdr.e_shnum; i++) {
-               struct section *sec = &secs[i];
-               if (fread(&shdr, sizeof shdr, 1, fp) != 1)
-                       die("Cannot read ELF section headers %d/%d: %s\n",
-                           i, ehdr.e_shnum, strerror(errno));
-               sec->shdr.sh_name      = 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);
-               if (sec->shdr.sh_link < ehdr.e_shnum)
-                       sec->link = &secs[sec->shdr.sh_link];
-       }
-
-}
-
-static void read_strtabs(FILE *fp)
-{
-       int i;
-       for (i = 0; i < ehdr.e_shnum; i++) {
-               struct section *sec = &secs[i];
-               if (sec->shdr.sh_type != SHT_STRTAB) {
-                       continue;
-               }
-               sec->strtab = malloc(sec->shdr.sh_size);
-               if (!sec->strtab) {
-                       die("malloc of %d bytes for strtab failed\n",
-                               sec->shdr.sh_size);
-               }
-               if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
-                       die("Seek to %d failed: %s\n",
-                               sec->shdr.sh_offset, strerror(errno));
-               }
-               if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
-                   != sec->shdr.sh_size) {
-                       die("Cannot read symbol table: %s\n",
-                               strerror(errno));
-               }
-       }
-}
-
-static void read_symtabs(FILE *fp)
-{
-       int i,j;
-       for (i = 0; i < ehdr.e_shnum; i++) {
-               struct section *sec = &secs[i];
-               if (sec->shdr.sh_type != SHT_SYMTAB) {
-                       continue;
-               }
-               sec->symtab = malloc(sec->shdr.sh_size);
-               if (!sec->symtab) {
-                       die("malloc of %d bytes for symtab failed\n",
-                               sec->shdr.sh_size);
-               }
-               if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
-                       die("Seek to %d failed: %s\n",
-                               sec->shdr.sh_offset, strerror(errno));
-               }
-               if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
-                   != sec->shdr.sh_size) {
-                       die("Cannot read symbol table: %s\n",
-                               strerror(errno));
-               }
-               for (j = 0; j < sec->shdr.sh_size/sizeof(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);
-               }
-       }
-}
-
-
-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) {
-                       continue;
-               }
-               sec->reltab = malloc(sec->shdr.sh_size);
-               if (!sec->reltab) {
-                       die("malloc of %d bytes for relocs failed\n",
-                               sec->shdr.sh_size);
-               }
-               if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
-                       die("Seek to %d failed: %s\n",
-                               sec->shdr.sh_offset, strerror(errno));
-               }
-               if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
-                   != sec->shdr.sh_size) {
-                       die("Cannot read symbol table: %s\n",
-                               strerror(errno));
-               }
-               for (j = 0; j < sec->shdr.sh_size/sizeof(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);
-               }
-       }
-}
-
-
-static void print_absolute_symbols(void)
-{
-       int i;
-       printf("Absolute symbols\n");
-       printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
-       for (i = 0; i < ehdr.e_shnum; i++) {
-               struct section *sec = &secs[i];
-               char *sym_strtab;
-               int j;
-
-               if (sec->shdr.sh_type != SHT_SYMTAB) {
-                       continue;
-               }
-               sym_strtab = sec->link->strtab;
-               for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
-                       Elf32_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",
-                               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)),
-                               name);
-               }
-       }
-       printf("\n");
-}
-
-static void print_absolute_relocs(void)
-{
-       int i, printed = 0;
-
-       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;
-               int j;
-               if (sec->shdr.sh_type != SHT_REL) {
-                       continue;
-               }
-               sec_symtab  = sec->link;
-               sec_applies = &secs[sec->shdr.sh_info];
-               if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
-                       continue;
-               }
-               sh_symtab  = sec_symtab->symtab;
-               sym_strtab = sec_symtab->link->strtab;
-               for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
-                       Elf32_Rel *rel;
-                       Elf32_Sym *sym;
-                       const char *name;
-                       rel = &sec->reltab[j];
-                       sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
-                       name = sym_name(sym_strtab, sym);
-                       if (sym->st_shndx != SHN_ABS) {
-                               continue;
-                       }
-
-                       /* Absolute symbols are not relocated if bzImage is
-                        * loaded at a non-compiled address. Display a warning
-                        * to user at compile time about the absolute
-                        * relocations present.
-                        *
-                        * User need to audit the code to make sure
-                        * some symbols which should have been section
-                        * relative have not become absolute because of some
-                        * linker optimization or wrong programming usage.
-                        *
-                        * Before warning check if this absolute symbol
-                        * relocation is harmless.
-                        */
-                       if (is_abs_reloc(name) || is_rel_reloc(name))
-                               continue;
-
-                       if (!printed) {
-                               printf("WARNING: Absolute relocations"
-                                       " present\n");
-                               printf("Offset     Info     Type     Sym.Value "
-                                       "Sym.Name\n");
-                               printed = 1;
-                       }
-
-                       printf("%08x %08x %10s %08x  %s\n",
-                               rel->r_offset,
-                               rel->r_info,
-                               rel_type(ELF32_R_TYPE(rel->r_info)),
-                               sym->st_value,
-                               name);
-               }
-       }
-
-       if (printed)
-               printf("\n");
-}
-
-static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
-{
-       int i;
-       /* Walk through the relocations */
-       for (i = 0; i < ehdr.e_shnum; i++) {
-               char *sym_strtab;
-               Elf32_Sym *sh_symtab;
-               struct section *sec_applies, *sec_symtab;
-               int j;
-               struct section *sec = &secs[i];
-
-               if (sec->shdr.sh_type != SHT_REL) {
-                       continue;
-               }
-               sec_symtab  = sec->link;
-               sec_applies = &secs[sec->shdr.sh_info];
-               if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
-                       continue;
-               }
-               sh_symtab = sec_symtab->symtab;
-               sym_strtab = sec_symtab->link->strtab;
-               for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
-                       Elf32_Rel *rel;
-                       Elf32_Sym *sym;
-                       unsigned r_type;
-                       rel = &sec->reltab[j];
-                       sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
-                       r_type = ELF32_R_TYPE(rel->r_info);
-                       /* Don't visit relocations to absolute symbols */
-                       if (sym->st_shndx == SHN_ABS &&
-                           !is_rel_reloc(sym_name(sym_strtab, sym))) {
-                               continue;
-                       }
-                       switch (r_type) {
-                       case R_386_NONE:
-                       case R_386_PC32:
-                               /*
-                                * NONE can be ignored and and PC relative
-                                * relocations don't need to be adjusted.
-                                */
-                               break;
-                       case R_386_32:
-                               /* Visit relocations that need to be adjusted */
-                               visit(rel, sym);
-                               break;
-                       default:
-                               die("Unsupported relocation type: %s (%d)\n",
-                                   rel_type(r_type), r_type);
-                               break;
-                       }
-               }
-       }
-}
-
-static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
-{
-       reloc_count += 1;
-}
-
-static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
-{
-       /* Remember the address that needs to be adjusted. */
-       relocs[reloc_idx++] = rel->r_offset;
-}
-
-static int cmp_relocs(const void *va, const void *vb)
-{
-       const unsigned long *a, *b;
-       a = va; b = vb;
-       return (*a == *b)? 0 : (*a > *b)? 1 : -1;
-}
-
-static void emit_relocs(int as_text)
-{
-       int i;
-       /* Count how many relocations I have and allocate space for them. */
-       reloc_count = 0;
-       walk_relocs(count_reloc);
-       relocs = malloc(reloc_count * sizeof(relocs[0]));
-       if (!relocs) {
-               die("malloc of %d entries for relocs failed\n",
-                       reloc_count);
-       }
-       /* Collect up the relocations */
-       reloc_idx = 0;
-       walk_relocs(collect_reloc);
-
-       /* Order the relocations for more efficient processing */
-       qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
-
-       /* Print the relocations */
-       if (as_text) {
-               /* Print the relocations in a form suitable that
-                * gas will like.
-                */
-               printf(".section \".data.reloc\",\"a\"\n");
-               printf(".balign 4\n");
-               for (i = 0; i < reloc_count; i++) {
-                       printf("\t .long 0x%08lx\n", relocs[i]);
-               }
-               printf("\n");
-       }
-       else {
-               unsigned char buf[4];
-               /* Print a stop */
-               fwrite("\0\0\0\0", 4, 1, stdout);
-               /* Now print each relocation */
-               for (i = 0; i < reloc_count; i++) {
-                       put_unaligned_le32(relocs[i], buf);
-                       fwrite(buf, 4, 1, stdout);
-               }
-       }
-}
-
-static void usage(void)
-{
-       die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
-}
-
-int main(int argc, char **argv)
-{
-       int show_absolute_syms, show_absolute_relocs;
-       int as_text;
-       const char *fname;
-       FILE *fp;
-       int i;
-
-       regex_init();
-
-       show_absolute_syms = 0;
-       show_absolute_relocs = 0;
-       as_text = 0;
-       fname = NULL;
-       for (i = 1; i < argc; i++) {
-               char *arg = argv[i];
-               if (*arg == '-') {
-                       if (strcmp(argv[1], "--abs-syms") == 0) {
-                               show_absolute_syms = 1;
-                               continue;
-                       }
-
-                       if (strcmp(argv[1], "--abs-relocs") == 0) {
-                               show_absolute_relocs = 1;
-                               continue;
-                       }
-                       else if (strcmp(argv[1], "--text") == 0) {
-                               as_text = 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));
-       }
-       read_ehdr(fp);
-       read_shdrs(fp);
-       read_strtabs(fp);
-       read_symtabs(fp);
-       read_relocs(fp);
-       if (show_absolute_syms) {
-               print_absolute_symbols();
-               return 0;
-       }
-       if (show_absolute_relocs) {
-               print_absolute_relocs();
-               return 0;
-       }
-       emit_relocs(as_text);
-       return 0;
-}
diff --git a/arch/x86/tools/.gitignore b/arch/x86/tools/.gitignore
new file mode 100644 (file)
index 0000000..be0ed06
--- /dev/null
@@ -0,0 +1 @@
+relocs
index d511aa9..733057b 100644 (file)
@@ -36,3 +36,7 @@ HOSTCFLAGS_insn_sanity.o := -Wall -I$(objtree)/arch/x86/lib/ -I$(srctree)/arch/x
 $(obj)/test_get_len.o: $(srctree)/arch/x86/lib/insn.c $(srctree)/arch/x86/lib/inat.c $(srctree)/arch/x86/include/asm/inat_types.h $(srctree)/arch/x86/include/asm/inat.h $(srctree)/arch/x86/include/asm/insn.h $(objtree)/arch/x86/lib/inat-tables.c
 
 $(obj)/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 $(objtree)/arch/x86/lib/inat-tables.c
+
+HOST_EXTRACFLAGS += -I$(srctree)/tools/include
+hostprogs-y    += relocs
+relocs: $(obj)/relocs
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
new file mode 100644 (file)
index 0000000..0291470
--- /dev/null
@@ -0,0 +1,797 @@
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <elf.h>
+#include <byteswap.h>
+#define USE_BSD
+#include <endian.h>
+#include <regex.h>
+#include <tools/le_byteshift.h>
+
+static void die(char *fmt, ...);
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+static Elf32_Ehdr ehdr;
+static unsigned long reloc_count, reloc_idx;
+static unsigned long *relocs;
+static unsigned long reloc16_count, reloc16_idx;
+static unsigned long *relocs16;
+
+struct section {
+       Elf32_Shdr     shdr;
+       struct section *link;
+       Elf32_Sym      *symtab;
+       Elf32_Rel      *reltab;
+       char           *strtab;
+};
+static struct section *secs;
+
+enum symtype {
+       S_ABS,
+       S_REL,
+       S_SEG,
+       S_LIN,
+       S_NSYMTYPES
+};
+
+static const char * const sym_regex_kernel[S_NSYMTYPES] = {
+/*
+ * Following symbols have been audited. There values are constant and do
+ * not change if bzImage is loaded at a different physical address than
+ * the address for which it has been compiled. Don't warn user about
+ * absolute relocations present w.r.t these symbols.
+ */
+       [S_ABS] =
+       "^(xen_irq_disable_direct_reloc$|"
+       "xen_save_fl_direct_reloc$|"
+       "VDSO|"
+       "__crc_)",
+
+/*
+ * These symbols are known to be relative, even if the linker marks them
+ * as absolute (typically defined outside any section in the linker script.)
+ */
+       [S_REL] =
+       "^_end$",
+};
+
+
+static const char * const sym_regex_realmode[S_NSYMTYPES] = {
+/*
+ * These are 16-bit segment symbols when compiling 16-bit code.
+ */
+       [S_SEG] =
+       "^real_mode_seg$",
+
+/*
+ * These are offsets belonging to segments, as opposed to linear addresses,
+ * when compiling 16-bit code.
+ */
+       [S_LIN] =
+       "^pa_",
+};
+
+static const char * const *sym_regex;
+
+static regex_t sym_regex_c[S_NSYMTYPES];
+static int is_reloc(enum symtype type, const char *sym_name)
+{
+       return sym_regex[type] &&
+               !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
+}
+
+static void regex_init(int use_real_mode)
+{
+        char errbuf[128];
+        int err;
+       int i;
+
+       if (use_real_mode)
+               sym_regex = sym_regex_realmode;
+       else
+               sym_regex = sym_regex_kernel;
+
+       for (i = 0; i < S_NSYMTYPES; i++) {
+               if (!sym_regex[i])
+                       continue;
+
+               err = regcomp(&sym_regex_c[i], sym_regex[i],
+                             REG_EXTENDED|REG_NOSUB);
+
+               if (err) {
+                       regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
+                       die("%s", errbuf);
+               }
+        }
+}
+
+static 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[] = {
+#define SYM_TYPE(X) [X] = #X
+               SYM_TYPE(STT_NOTYPE),
+               SYM_TYPE(STT_OBJECT),
+               SYM_TYPE(STT_FUNC),
+               SYM_TYPE(STT_SECTION),
+               SYM_TYPE(STT_FILE),
+               SYM_TYPE(STT_COMMON),
+               SYM_TYPE(STT_TLS),
+#undef SYM_TYPE
+       };
+       const char *name = "unknown sym type name";
+       if (type < ARRAY_SIZE(type_name)) {
+               name = type_name[type];
+       }
+       return name;
+}
+
+static const char *sym_bind(unsigned bind)
+{
+       static const char *bind_name[] = {
+#define SYM_BIND(X) [X] = #X
+               SYM_BIND(STB_LOCAL),
+               SYM_BIND(STB_GLOBAL),
+               SYM_BIND(STB_WEAK),
+#undef SYM_BIND
+       };
+       const char *name = "unknown sym bind name";
+       if (bind < ARRAY_SIZE(bind_name)) {
+               name = bind_name[bind];
+       }
+       return name;
+}
+
+static const char *sym_visibility(unsigned visibility)
+{
+       static const char *visibility_name[] = {
+#define SYM_VISIBILITY(X) [X] = #X
+               SYM_VISIBILITY(STV_DEFAULT),
+               SYM_VISIBILITY(STV_INTERNAL),
+               SYM_VISIBILITY(STV_HIDDEN),
+               SYM_VISIBILITY(STV_PROTECTED),
+#undef SYM_VISIBILITY
+       };
+       const char *name = "unknown sym visibility name";
+       if (visibility < ARRAY_SIZE(visibility_name)) {
+               name = visibility_name[visibility];
+       }
+       return name;
+}
+
+static const char *rel_type(unsigned type)
+{
+       static const char *type_name[] = {
+#define REL_TYPE(X) [X] = #X
+               REL_TYPE(R_386_NONE),
+               REL_TYPE(R_386_32),
+               REL_TYPE(R_386_PC32),
+               REL_TYPE(R_386_GOT32),
+               REL_TYPE(R_386_PLT32),
+               REL_TYPE(R_386_COPY),
+               REL_TYPE(R_386_GLOB_DAT),
+               REL_TYPE(R_386_JMP_SLOT),
+               REL_TYPE(R_386_RELATIVE),
+               REL_TYPE(R_386_GOTOFF),
+               REL_TYPE(R_386_GOTPC),
+               REL_TYPE(R_386_8),
+               REL_TYPE(R_386_PC8),
+               REL_TYPE(R_386_16),
+               REL_TYPE(R_386_PC16),
+#undef REL_TYPE
+       };
+       const char *name = "unknown type rel type name";
+       if (type < ARRAY_SIZE(type_name) && type_name[type]) {
+               name = type_name[type];
+       }
+       return name;
+}
+
+static const char *sec_name(unsigned shndx)
+{
+       const char *sec_strtab;
+       const char *name;
+       sec_strtab = secs[ehdr.e_shstrndx].strtab;
+       name = "<noname>";
+       if (shndx < ehdr.e_shnum) {
+               name = sec_strtab + secs[shndx].shdr.sh_name;
+       }
+       else if (shndx == SHN_ABS) {
+               name = "ABSOLUTE";
+       }
+       else if (shndx == SHN_COMMON) {
+               name = "COMMON";
+       }
+       return name;
+}
+
+static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
+{
+       const char *name;
+       name = "<noname>";
+       if (sym->st_name) {
+               name = sym_strtab + sym->st_name;
+       }
+       else {
+               name = sec_name(sym->st_shndx);
+       }
+       return name;
+}
+
+
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define le16_to_cpu(val) (val)
+#define le32_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)
+#endif
+
+static uint16_t elf16_to_cpu(uint16_t val)
+{
+       return le16_to_cpu(val);
+}
+
+static uint32_t elf32_to_cpu(uint32_t val)
+{
+       return le32_to_cpu(val);
+}
+
+static void read_ehdr(FILE *fp)
+{
+       if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
+               die("Cannot read ELF header: %s\n",
+                       strerror(errno));
+       }
+       if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
+               die("No ELF magic\n");
+       }
+       if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
+               die("Not a 32 bit executable\n");
+       }
+       if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
+               die("Not a LSB ELF executable\n");
+       }
+       if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
+               die("Unknown ELF version\n");
+       }
+       /* Convert the fields to native endian */
+       ehdr.e_type      = 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);
+
+       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_version != EV_CURRENT) {
+               die("Unknown ELF version\n");
+       }
+       if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
+               die("Bad Elf header size\n");
+       }
+       if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
+               die("Bad program header entry\n");
+       }
+       if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
+               die("Bad section header entry\n");
+       }
+       if (ehdr.e_shstrndx >= ehdr.e_shnum) {
+               die("String table index out of bounds\n");
+       }
+}
+
+static void read_shdrs(FILE *fp)
+{
+       int i;
+       Elf32_Shdr shdr;
+
+       secs = calloc(ehdr.e_shnum, sizeof(struct section));
+       if (!secs) {
+               die("Unable to allocate %d section headers\n",
+                   ehdr.e_shnum);
+       }
+       if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
+               die("Seek to %d failed: %s\n",
+                       ehdr.e_shoff, strerror(errno));
+       }
+       for (i = 0; i < ehdr.e_shnum; i++) {
+               struct section *sec = &secs[i];
+               if (fread(&shdr, sizeof shdr, 1, fp) != 1)
+                       die("Cannot read ELF section headers %d/%d: %s\n",
+                           i, ehdr.e_shnum, strerror(errno));
+               sec->shdr.sh_name      = 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);
+               if (sec->shdr.sh_link < ehdr.e_shnum)
+                       sec->link = &secs[sec->shdr.sh_link];
+       }
+
+}
+
+static void read_strtabs(FILE *fp)
+{
+       int i;
+       for (i = 0; i < ehdr.e_shnum; i++) {
+               struct section *sec = &secs[i];
+               if (sec->shdr.sh_type != SHT_STRTAB) {
+                       continue;
+               }
+               sec->strtab = malloc(sec->shdr.sh_size);
+               if (!sec->strtab) {
+                       die("malloc of %d bytes for strtab failed\n",
+                               sec->shdr.sh_size);
+               }
+               if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
+                       die("Seek to %d failed: %s\n",
+                               sec->shdr.sh_offset, strerror(errno));
+               }
+               if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
+                   != sec->shdr.sh_size) {
+                       die("Cannot read symbol table: %s\n",
+                               strerror(errno));
+               }
+       }
+}
+
+static void read_symtabs(FILE *fp)
+{
+       int i,j;
+       for (i = 0; i < ehdr.e_shnum; i++) {
+               struct section *sec = &secs[i];
+               if (sec->shdr.sh_type != SHT_SYMTAB) {
+                       continue;
+               }
+               sec->symtab = malloc(sec->shdr.sh_size);
+               if (!sec->symtab) {
+                       die("malloc of %d bytes for symtab failed\n",
+                               sec->shdr.sh_size);
+               }
+               if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
+                       die("Seek to %d failed: %s\n",
+                               sec->shdr.sh_offset, strerror(errno));
+               }
+               if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
+                   != sec->shdr.sh_size) {
+                       die("Cannot read symbol table: %s\n",
+                               strerror(errno));
+               }
+               for (j = 0; j < sec->shdr.sh_size/sizeof(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);
+               }
+       }
+}
+
+
+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) {
+                       continue;
+               }
+               sec->reltab = malloc(sec->shdr.sh_size);
+               if (!sec->reltab) {
+                       die("malloc of %d bytes for relocs failed\n",
+                               sec->shdr.sh_size);
+               }
+               if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
+                       die("Seek to %d failed: %s\n",
+                               sec->shdr.sh_offset, strerror(errno));
+               }
+               if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
+                   != sec->shdr.sh_size) {
+                       die("Cannot read symbol table: %s\n",
+                               strerror(errno));
+               }
+               for (j = 0; j < sec->shdr.sh_size/sizeof(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);
+               }
+       }
+}
+
+
+static void print_absolute_symbols(void)
+{
+       int i;
+       printf("Absolute symbols\n");
+       printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
+       for (i = 0; i < ehdr.e_shnum; i++) {
+               struct section *sec = &secs[i];
+               char *sym_strtab;
+               int j;
+
+               if (sec->shdr.sh_type != SHT_SYMTAB) {
+                       continue;
+               }
+               sym_strtab = sec->link->strtab;
+               for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
+                       Elf32_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",
+                               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)),
+                               name);
+               }
+       }
+       printf("\n");
+}
+
+static void print_absolute_relocs(void)
+{
+       int i, printed = 0;
+
+       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;
+               int j;
+               if (sec->shdr.sh_type != SHT_REL) {
+                       continue;
+               }
+               sec_symtab  = sec->link;
+               sec_applies = &secs[sec->shdr.sh_info];
+               if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
+                       continue;
+               }
+               sh_symtab  = sec_symtab->symtab;
+               sym_strtab = sec_symtab->link->strtab;
+               for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
+                       Elf32_Rel *rel;
+                       Elf32_Sym *sym;
+                       const char *name;
+                       rel = &sec->reltab[j];
+                       sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
+                       name = sym_name(sym_strtab, sym);
+                       if (sym->st_shndx != SHN_ABS) {
+                               continue;
+                       }
+
+                       /* Absolute symbols are not relocated if bzImage is
+                        * loaded at a non-compiled address. Display a warning
+                        * to user at compile time about the absolute
+                        * relocations present.
+                        *
+                        * User need to audit the code to make sure
+                        * some symbols which should have been section
+                        * relative have not become absolute because of some
+                        * linker optimization or wrong programming usage.
+                        *
+                        * Before warning check if this absolute symbol
+                        * relocation is harmless.
+                        */
+                       if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
+                               continue;
+
+                       if (!printed) {
+                               printf("WARNING: Absolute relocations"
+                                       " present\n");
+                               printf("Offset     Info     Type     Sym.Value "
+                                       "Sym.Name\n");
+                               printed = 1;
+                       }
+
+                       printf("%08x %08x %10s %08x  %s\n",
+                               rel->r_offset,
+                               rel->r_info,
+                               rel_type(ELF32_R_TYPE(rel->r_info)),
+                               sym->st_value,
+                               name);
+               }
+       }
+
+       if (printed)
+               printf("\n");
+}
+
+static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_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;
+               struct section *sec_applies, *sec_symtab;
+               int j;
+               struct section *sec = &secs[i];
+
+               if (sec->shdr.sh_type != SHT_REL) {
+                       continue;
+               }
+               sec_symtab  = sec->link;
+               sec_applies = &secs[sec->shdr.sh_info];
+               if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
+                       continue;
+               }
+               sh_symtab = sec_symtab->symtab;
+               sym_strtab = sec_symtab->link->strtab;
+               for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
+                       Elf32_Rel *rel;
+                       Elf32_Sym *sym;
+                       unsigned r_type;
+                       const char *symname;
+                       rel = &sec->reltab[j];
+                       sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
+                       r_type = ELF32_R_TYPE(rel->r_info);
+
+                       switch (r_type) {
+                       case R_386_NONE:
+                       case R_386_PC32:
+                       case R_386_PC16:
+                       case R_386_PC8:
+                               /*
+                                * NONE can be ignored and and PC relative
+                                * relocations don't need to be adjusted.
+                                */
+                               break;
+
+                       case R_386_16:
+                               symname = sym_name(sym_strtab, sym);
+                               if (!use_real_mode)
+                                       goto bad;
+                               if (sym->st_shndx == SHN_ABS) {
+                                       if (is_reloc(S_ABS, symname))
+                                               break;
+                                       else if (!is_reloc(S_SEG, symname))
+                                               goto bad;
+                               } else {
+                                       if (is_reloc(S_LIN, symname))
+                                               goto bad;
+                                       else
+                                               break;
+                               }
+                               visit(rel, sym);
+                               break;
+
+                       case R_386_32:
+                               symname = sym_name(sym_strtab, sym);
+                               if (sym->st_shndx == SHN_ABS) {
+                                       if (is_reloc(S_ABS, symname))
+                                               break;
+                                       else if (!is_reloc(S_REL, symname))
+                                               goto bad;
+                               } else {
+                                       if (use_real_mode &&
+                                           !is_reloc(S_LIN, symname))
+                                               break;
+                               }
+                               visit(rel, sym);
+                               break;
+                       default:
+                               die("Unsupported relocation type: %s (%d)\n",
+                                   rel_type(r_type), r_type);
+                               break;
+                       bad:
+                               symname = sym_name(sym_strtab, sym);
+                               die("Invalid %s relocation: %s\n",
+                                   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++;
+}
+
+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;
+}
+
+static int cmp_relocs(const void *va, const void *vb)
+{
+       const unsigned long *a, *b;
+       a = va; b = vb;
+       return (*a == *b)? 0 : (*a > *b)? 1 : -1;
+}
+
+static int write32(unsigned int v, FILE *f)
+{
+       unsigned char buf[4];
+
+       put_unaligned_le32(v, buf);
+       return fwrite(buf, 1, 4, f) == 4 ? 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);
+       }
+
+       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);
+
+       if (reloc16_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);
+
+       /* Print the relocations */
+       if (as_text) {
+               /* Print the relocations in a form suitable that
+                * gas will like.
+                */
+               printf(".section \".data.reloc\",\"a\"\n");
+               printf(".balign 4\n");
+               if (use_real_mode) {
+                       printf("\t.long %lu\n", reloc16_count);
+                       for (i = 0; i < reloc16_count; i++)
+                               printf("\t.long 0x%08lx\n", relocs16[i]);
+                       printf("\t.long %lu\n", reloc_count);
+                       for (i = 0; i < reloc_count; i++) {
+                               printf("\t.long 0x%08lx\n", relocs[i]);
+                       }
+               } else {
+                       /* Print a stop */
+                       printf("\t.long 0x%08lx\n", (unsigned long)0);
+                       for (i = 0; i < reloc_count; i++) {
+                               printf("\t.long 0x%08lx\n", relocs[i]);
+                       }
+               }
+
+               printf("\n");
+       }
+       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);
+                       }
+               }
+       }
+}
+
+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;
+
+       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 (show_absolute_syms) {
+               print_absolute_symbols();
+               return 0;
+       }
+       if (show_absolute_relocs) {
+               print_absolute_relocs();
+               return 0;
+       }
+       emit_relocs(as_text, use_real_mode);
+       return 0;
+}
index df7678f..3626666 100644 (file)
@@ -8,6 +8,8 @@
 # conmakehash:  Create arrays for initializing the kernel console tables
 # docproc:       Used in Documentation/DocBook
 
+HOST_EXTRACFLAGS += -I$(srctree)/tools/include
+
 hostprogs-$(CONFIG_KALLSYMS)     += kallsyms
 hostprogs-$(CONFIG_LOGO)         += pnmtologo
 hostprogs-$(CONFIG_VT)           += conmakehash