![Stefani Seibold](/assets/img/avatar_default.png)
This patch move the vsyscall_gtod_data handling out of vsyscall_64.c into an additonal file vsyscall_gtod.c to make the functionality available for x86 32 bit kernel. It also adds a new vsyscall_32.c which setup the VVAR page. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-2-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
1083 lines
26 KiB
C
1083 lines
26 KiB
C
/* This is included from relocs_32/64.c */
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#define ElfW(type) _ElfW(ELF_BITS, type)
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#define _ElfW(bits, type) __ElfW(bits, type)
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#define __ElfW(bits, type) Elf##bits##_##type
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#define Elf_Addr ElfW(Addr)
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#define Elf_Ehdr ElfW(Ehdr)
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#define Elf_Phdr ElfW(Phdr)
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#define Elf_Shdr ElfW(Shdr)
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#define Elf_Sym ElfW(Sym)
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static Elf_Ehdr ehdr;
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struct relocs {
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uint32_t *offset;
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unsigned long count;
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unsigned long size;
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};
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static struct relocs relocs16;
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static struct relocs relocs32;
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static struct relocs relocs64;
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struct section {
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Elf_Shdr shdr;
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struct section *link;
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Elf_Sym *symtab;
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Elf_Rel *reltab;
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char *strtab;
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};
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static struct section *secs;
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static const char * const sym_regex_kernel[S_NSYMTYPES] = {
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/*
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* Following symbols have been audited. There values are constant and do
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* not change if bzImage is loaded at a different physical address than
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* the address for which it has been compiled. Don't warn user about
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* absolute relocations present w.r.t these symbols.
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*/
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[S_ABS] =
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"^(xen_irq_disable_direct_reloc$|"
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"xen_save_fl_direct_reloc$|"
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"VDSO|"
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"__crc_)",
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/*
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* These symbols are known to be relative, even if the linker marks them
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* as absolute (typically defined outside any section in the linker script.)
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*/
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[S_REL] =
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"^(__init_(begin|end)|"
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"__x86_cpu_dev_(start|end)|"
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"(__parainstructions|__alt_instructions)(|_end)|"
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"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
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"__(start|end)_pci_.*|"
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"__(start|end)_builtin_fw|"
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"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
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"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
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"__(start|stop)___param|"
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"__(start|stop)___modver|"
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"__(start|stop)___bug_table|"
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"__tracedata_(start|end)|"
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"__(start|stop)_notes|"
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"__end_rodata|"
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"__initramfs_start|"
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"(jiffies|jiffies_64)|"
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#if ELF_BITS == 64
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"__per_cpu_load|"
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"init_per_cpu__.*|"
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"__end_rodata_hpage_align|"
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#endif
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"__vvar_page|"
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"_end)$"
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};
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static const char * const sym_regex_realmode[S_NSYMTYPES] = {
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/*
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* These symbols are known to be relative, even if the linker marks them
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* as absolute (typically defined outside any section in the linker script.)
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*/
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[S_REL] =
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"^pa_",
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/*
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* These are 16-bit segment symbols when compiling 16-bit code.
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*/
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[S_SEG] =
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"^real_mode_seg$",
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/*
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* These are offsets belonging to segments, as opposed to linear addresses,
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* when compiling 16-bit code.
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*/
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[S_LIN] =
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"^pa_",
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};
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static const char * const *sym_regex;
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static regex_t sym_regex_c[S_NSYMTYPES];
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static int is_reloc(enum symtype type, const char *sym_name)
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{
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return sym_regex[type] &&
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!regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
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}
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static void regex_init(int use_real_mode)
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{
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char errbuf[128];
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int err;
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int i;
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if (use_real_mode)
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sym_regex = sym_regex_realmode;
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else
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sym_regex = sym_regex_kernel;
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for (i = 0; i < S_NSYMTYPES; i++) {
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if (!sym_regex[i])
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continue;
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err = regcomp(&sym_regex_c[i], sym_regex[i],
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REG_EXTENDED|REG_NOSUB);
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if (err) {
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regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
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die("%s", errbuf);
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}
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}
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}
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static const char *sym_type(unsigned type)
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{
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static const char *type_name[] = {
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#define SYM_TYPE(X) [X] = #X
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SYM_TYPE(STT_NOTYPE),
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SYM_TYPE(STT_OBJECT),
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SYM_TYPE(STT_FUNC),
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SYM_TYPE(STT_SECTION),
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SYM_TYPE(STT_FILE),
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SYM_TYPE(STT_COMMON),
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SYM_TYPE(STT_TLS),
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#undef SYM_TYPE
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};
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const char *name = "unknown sym type name";
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if (type < ARRAY_SIZE(type_name)) {
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name = type_name[type];
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}
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return name;
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}
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static const char *sym_bind(unsigned bind)
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{
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static const char *bind_name[] = {
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#define SYM_BIND(X) [X] = #X
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SYM_BIND(STB_LOCAL),
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SYM_BIND(STB_GLOBAL),
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SYM_BIND(STB_WEAK),
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#undef SYM_BIND
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};
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const char *name = "unknown sym bind name";
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if (bind < ARRAY_SIZE(bind_name)) {
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name = bind_name[bind];
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}
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return name;
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}
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static const char *sym_visibility(unsigned visibility)
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{
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static const char *visibility_name[] = {
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#define SYM_VISIBILITY(X) [X] = #X
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SYM_VISIBILITY(STV_DEFAULT),
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SYM_VISIBILITY(STV_INTERNAL),
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SYM_VISIBILITY(STV_HIDDEN),
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SYM_VISIBILITY(STV_PROTECTED),
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#undef SYM_VISIBILITY
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};
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const char *name = "unknown sym visibility name";
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if (visibility < ARRAY_SIZE(visibility_name)) {
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name = visibility_name[visibility];
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}
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return name;
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}
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static const char *rel_type(unsigned type)
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{
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static const char *type_name[] = {
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#define REL_TYPE(X) [X] = #X
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#if ELF_BITS == 64
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REL_TYPE(R_X86_64_NONE),
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REL_TYPE(R_X86_64_64),
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REL_TYPE(R_X86_64_PC32),
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REL_TYPE(R_X86_64_GOT32),
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REL_TYPE(R_X86_64_PLT32),
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REL_TYPE(R_X86_64_COPY),
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REL_TYPE(R_X86_64_GLOB_DAT),
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REL_TYPE(R_X86_64_JUMP_SLOT),
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REL_TYPE(R_X86_64_RELATIVE),
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REL_TYPE(R_X86_64_GOTPCREL),
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REL_TYPE(R_X86_64_32),
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REL_TYPE(R_X86_64_32S),
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REL_TYPE(R_X86_64_16),
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REL_TYPE(R_X86_64_PC16),
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REL_TYPE(R_X86_64_8),
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REL_TYPE(R_X86_64_PC8),
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#else
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REL_TYPE(R_386_NONE),
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REL_TYPE(R_386_32),
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REL_TYPE(R_386_PC32),
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REL_TYPE(R_386_GOT32),
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REL_TYPE(R_386_PLT32),
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REL_TYPE(R_386_COPY),
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REL_TYPE(R_386_GLOB_DAT),
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REL_TYPE(R_386_JMP_SLOT),
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REL_TYPE(R_386_RELATIVE),
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REL_TYPE(R_386_GOTOFF),
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REL_TYPE(R_386_GOTPC),
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REL_TYPE(R_386_8),
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REL_TYPE(R_386_PC8),
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REL_TYPE(R_386_16),
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REL_TYPE(R_386_PC16),
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#endif
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#undef REL_TYPE
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};
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const char *name = "unknown type rel type name";
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if (type < ARRAY_SIZE(type_name) && type_name[type]) {
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name = type_name[type];
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}
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return name;
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}
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static const char *sec_name(unsigned shndx)
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{
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const char *sec_strtab;
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const char *name;
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sec_strtab = secs[ehdr.e_shstrndx].strtab;
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name = "<noname>";
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if (shndx < ehdr.e_shnum) {
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name = sec_strtab + secs[shndx].shdr.sh_name;
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}
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else if (shndx == SHN_ABS) {
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name = "ABSOLUTE";
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}
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else if (shndx == SHN_COMMON) {
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name = "COMMON";
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}
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return name;
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}
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static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
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{
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const char *name;
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name = "<noname>";
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if (sym->st_name) {
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name = sym_strtab + sym->st_name;
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}
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else {
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name = sec_name(sym->st_shndx);
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}
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return name;
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}
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static Elf_Sym *sym_lookup(const char *symname)
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{
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int i;
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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long nsyms;
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char *strtab;
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Elf_Sym *symtab;
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Elf_Sym *sym;
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if (sec->shdr.sh_type != SHT_SYMTAB)
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continue;
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nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
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symtab = sec->symtab;
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strtab = sec->link->strtab;
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for (sym = symtab; --nsyms >= 0; sym++) {
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if (!sym->st_name)
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continue;
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if (strcmp(symname, strtab + sym->st_name) == 0)
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return sym;
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}
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}
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return 0;
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}
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#if BYTE_ORDER == LITTLE_ENDIAN
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#define le16_to_cpu(val) (val)
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#define le32_to_cpu(val) (val)
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#define le64_to_cpu(val) (val)
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#endif
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#if BYTE_ORDER == BIG_ENDIAN
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#define le16_to_cpu(val) bswap_16(val)
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#define le32_to_cpu(val) bswap_32(val)
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#define le64_to_cpu(val) bswap_64(val)
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#endif
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static uint16_t elf16_to_cpu(uint16_t val)
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{
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return le16_to_cpu(val);
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}
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static uint32_t elf32_to_cpu(uint32_t val)
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{
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return le32_to_cpu(val);
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}
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#define elf_half_to_cpu(x) elf16_to_cpu(x)
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#define elf_word_to_cpu(x) elf32_to_cpu(x)
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#if ELF_BITS == 64
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static uint64_t elf64_to_cpu(uint64_t val)
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{
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return le64_to_cpu(val);
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}
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#define elf_addr_to_cpu(x) elf64_to_cpu(x)
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#define elf_off_to_cpu(x) elf64_to_cpu(x)
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#define elf_xword_to_cpu(x) elf64_to_cpu(x)
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#else
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#define elf_addr_to_cpu(x) elf32_to_cpu(x)
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#define elf_off_to_cpu(x) elf32_to_cpu(x)
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#define elf_xword_to_cpu(x) elf32_to_cpu(x)
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#endif
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static void read_ehdr(FILE *fp)
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{
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if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
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die("Cannot read ELF header: %s\n",
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strerror(errno));
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}
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if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
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die("No ELF magic\n");
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}
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if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
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die("Not a %d bit executable\n", ELF_BITS);
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}
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if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
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die("Not a LSB ELF executable\n");
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}
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if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
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die("Unknown ELF version\n");
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}
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/* Convert the fields to native endian */
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ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
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ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
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ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
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ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
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ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
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ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
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ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
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ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
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ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
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ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
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ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
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ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
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ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
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if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
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die("Unsupported ELF header type\n");
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}
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if (ehdr.e_machine != ELF_MACHINE) {
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die("Not for %s\n", ELF_MACHINE_NAME);
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}
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if (ehdr.e_version != EV_CURRENT) {
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die("Unknown ELF version\n");
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}
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if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
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die("Bad Elf header size\n");
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}
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if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
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die("Bad program header entry\n");
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}
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if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
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die("Bad section header entry\n");
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}
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if (ehdr.e_shstrndx >= ehdr.e_shnum) {
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die("String table index out of bounds\n");
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}
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}
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static void read_shdrs(FILE *fp)
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{
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int i;
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Elf_Shdr shdr;
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secs = calloc(ehdr.e_shnum, sizeof(struct section));
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if (!secs) {
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die("Unable to allocate %d section headers\n",
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ehdr.e_shnum);
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}
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if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
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die("Seek to %d failed: %s\n",
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ehdr.e_shoff, strerror(errno));
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}
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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if (fread(&shdr, sizeof shdr, 1, fp) != 1)
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die("Cannot read ELF section headers %d/%d: %s\n",
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i, ehdr.e_shnum, strerror(errno));
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sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
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sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
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sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
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sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
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sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
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sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
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sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
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sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
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sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
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sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
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if (sec->shdr.sh_link < ehdr.e_shnum)
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sec->link = &secs[sec->shdr.sh_link];
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}
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}
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static void read_strtabs(FILE *fp)
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{
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int i;
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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if (sec->shdr.sh_type != SHT_STRTAB) {
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continue;
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}
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sec->strtab = malloc(sec->shdr.sh_size);
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if (!sec->strtab) {
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die("malloc of %d bytes for strtab failed\n",
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sec->shdr.sh_size);
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}
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if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
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die("Seek to %d failed: %s\n",
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sec->shdr.sh_offset, strerror(errno));
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}
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if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
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!= sec->shdr.sh_size) {
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die("Cannot read symbol table: %s\n",
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strerror(errno));
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}
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}
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}
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static void read_symtabs(FILE *fp)
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{
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int i,j;
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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if (sec->shdr.sh_type != SHT_SYMTAB) {
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continue;
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}
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sec->symtab = malloc(sec->shdr.sh_size);
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if (!sec->symtab) {
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die("malloc of %d bytes for symtab failed\n",
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sec->shdr.sh_size);
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}
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if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
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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(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);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
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_TYPE) {
|
|
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(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
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
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++) {
|
|
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(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(format,
|
|
j, sym->st_value, sym->st_size,
|
|
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);
|
|
}
|
|
}
|
|
printf("\n");
|
|
}
|
|
|
|
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;
|
|
Elf_Sym *sh_symtab;
|
|
int j;
|
|
if (sec->shdr.sh_type != SHT_REL_TYPE) {
|
|
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(Elf_Rel); j++) {
|
|
Elf_Rel *rel;
|
|
Elf_Sym *sym;
|
|
const char *name;
|
|
rel = &sec->reltab[j];
|
|
sym = &sh_symtab[ELF_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(format,
|
|
rel->r_offset,
|
|
rel->r_info,
|
|
rel_type(ELF_R_TYPE(rel->r_info)),
|
|
sym->st_value,
|
|
name);
|
|
}
|
|
}
|
|
|
|
if (printed)
|
|
printf("\n");
|
|
}
|
|
|
|
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;
|
|
Elf_Sym *sh_symtab;
|
|
struct section *sec_applies, *sec_symtab;
|
|
int j;
|
|
struct section *sec = &secs[i];
|
|
|
|
if (sec->shdr.sh_type != SHT_REL_TYPE) {
|
|
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(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);
|
|
|
|
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.
|
|
*
|
|
* The linker incorrectly associates some symbols with the
|
|
* .data..percpu section so we also need to check the symbol
|
|
* name to make sure that we classify the symbol correctly.
|
|
*
|
|
* The GNU linker incorrectly associates:
|
|
* __init_begin
|
|
* __per_cpu_load
|
|
*
|
|
* The "gold" linker incorrectly associates:
|
|
* init_per_cpu__irq_stack_union
|
|
* init_per_cpu__gdt_page
|
|
*/
|
|
static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
|
|
{
|
|
return (sym->st_shndx == per_cpu_shndx) &&
|
|
strcmp(symname, "__init_begin") &&
|
|
strcmp(symname, "__per_cpu_load") &&
|
|
strncmp(symname, "init_per_cpu_", 13);
|
|
}
|
|
|
|
|
|
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;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
|
|
const char *symname)
|
|
{
|
|
unsigned r_type = ELF32_R_TYPE(rel->r_info);
|
|
int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
|
|
|
|
switch (r_type) {
|
|
case R_386_NONE:
|
|
case R_386_PC32:
|
|
case R_386_PC16:
|
|
case R_386_PC8:
|
|
/*
|
|
* NONE can be ignored and PC relative relocations don't
|
|
* need to be adjusted.
|
|
*/
|
|
break;
|
|
|
|
case R_386_16:
|
|
if (shn_abs) {
|
|
/*
|
|
* Whitelisted absolute symbols do not require
|
|
* relocation.
|
|
*/
|
|
if (is_reloc(S_ABS, symname))
|
|
break;
|
|
|
|
if (is_reloc(S_SEG, symname)) {
|
|
add_reloc(&relocs16, rel->r_offset);
|
|
break;
|
|
}
|
|
} else {
|
|
if (!is_reloc(S_LIN, symname))
|
|
break;
|
|
}
|
|
die("Invalid %s %s relocation: %s\n",
|
|
shn_abs ? "absolute" : "relative",
|
|
rel_type(r_type), symname);
|
|
break;
|
|
|
|
case R_386_32:
|
|
if (shn_abs) {
|
|
/*
|
|
* Whitelisted absolute symbols do not require
|
|
* relocation.
|
|
*/
|
|
if (is_reloc(S_ABS, symname))
|
|
break;
|
|
|
|
if (is_reloc(S_REL, symname)) {
|
|
add_reloc(&relocs32, rel->r_offset);
|
|
break;
|
|
}
|
|
} else {
|
|
if (is_reloc(S_LIN, symname))
|
|
add_reloc(&relocs32, rel->r_offset);
|
|
break;
|
|
}
|
|
die("Invalid %s %s relocation: %s\n",
|
|
shn_abs ? "absolute" : "relative",
|
|
rel_type(r_type), symname);
|
|
break;
|
|
|
|
default:
|
|
die("Unsupported relocation type: %s (%d)\n",
|
|
rel_type(r_type), r_type);
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
static int cmp_relocs(const void *va, const void *vb)
|
|
{
|
|
const uint32_t *a, *b;
|
|
a = va; b = vb;
|
|
return (*a == *b)? 0 : (*a > *b)? 1 : -1;
|
|
}
|
|
|
|
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];
|
|
|
|
put_unaligned_le32(v, buf);
|
|
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;
|
|
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
|
|
|
|
/* Collect up the relocations */
|
|
walk_relocs(do_reloc);
|
|
|
|
if (relocs16.count && !use_real_mode)
|
|
die("Segment relocations found but --realmode not specified\n");
|
|
|
|
/* Order the relocations for more efficient processing */
|
|
sort_relocs(&relocs16);
|
|
sort_relocs(&relocs32);
|
|
sort_relocs(&relocs64);
|
|
|
|
/* 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");
|
|
write_reloc = write32_as_text;
|
|
}
|
|
|
|
if (use_real_mode) {
|
|
write_reloc(relocs16.count, stdout);
|
|
for (i = 0; i < relocs16.count; i++)
|
|
write_reloc(relocs16.offset[i], stdout);
|
|
|
|
write_reloc(relocs32.count, stdout);
|
|
for (i = 0; i < relocs32.count; i++)
|
|
write_reloc(relocs32.offset[i], stdout);
|
|
} else {
|
|
if (ELF_BITS == 64) {
|
|
/* Print a stop */
|
|
write_reloc(0, stdout);
|
|
|
|
/* Now print each relocation */
|
|
for (i = 0; i < relocs64.count; i++)
|
|
write_reloc(relocs64.offset[i], stdout);
|
|
}
|
|
|
|
/* Print a stop */
|
|
write_reloc(0, stdout);
|
|
|
|
/* Now print each relocation */
|
|
for (i = 0; i < relocs32.count; i++)
|
|
write_reloc(relocs32.offset[i], stdout);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* As an aid to debugging problems with different linkers
|
|
* print summary information about the relocs.
|
|
* Since different linkers tend to emit the sections in
|
|
* different orders we use the section names in the output.
|
|
*/
|
|
static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
|
|
const char *symname)
|
|
{
|
|
printf("%s\t%s\t%s\t%s\n",
|
|
sec_name(sec->shdr.sh_info),
|
|
rel_type(ELF_R_TYPE(rel->r_info)),
|
|
symname,
|
|
sec_name(sym->st_shndx));
|
|
return 0;
|
|
}
|
|
|
|
static void print_reloc_info(void)
|
|
{
|
|
printf("reloc section\treloc type\tsymbol\tsymbol section\n");
|
|
walk_relocs(do_reloc_info);
|
|
}
|
|
|
|
#if ELF_BITS == 64
|
|
# define process process_64
|
|
#else
|
|
# define process process_32
|
|
#endif
|
|
|
|
void process(FILE *fp, int use_real_mode, int as_text,
|
|
int show_absolute_syms, int show_absolute_relocs,
|
|
int show_reloc_info)
|
|
{
|
|
regex_init(use_real_mode);
|
|
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();
|
|
return;
|
|
}
|
|
if (show_absolute_relocs) {
|
|
print_absolute_relocs();
|
|
return;
|
|
}
|
|
if (show_reloc_info) {
|
|
print_reloc_info();
|
|
return;
|
|
}
|
|
emit_relocs(as_text, use_real_mode);
|
|
}
|