Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1110 insertions, 0 deletions

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
new file mode 100644
index 000000000..aa046d46f
--- /dev/null
+++ b/arch/x86/tools/relocs.c
@@ -0,0 +1,1110 @@
+// SPDX-License-Identifier: GPL-2.0
+/* This is included from relocs_32/64.c */
+
+#define ElfW(type)		_ElfW(ELF_BITS, type)
+#define _ElfW(bits, type)	__ElfW(bits, type)
+#define __ElfW(bits, type)	Elf##bits##_##type
+
+#define Elf_Addr		ElfW(Addr)
+#define Elf_Ehdr		ElfW(Ehdr)
+#define Elf_Phdr		ElfW(Phdr)
+#define Elf_Shdr		ElfW(Shdr)
+#define Elf_Sym			ElfW(Sym)
+
+static Elf_Ehdr ehdr;
+
+struct relocs {
+	uint32_t	*offset;
+	unsigned long	count;
+	unsigned long	size;
+};
+
+static struct relocs relocs16;
+static struct relocs relocs32;
+#if ELF_BITS == 64
+static struct relocs relocs32neg;
+static struct relocs relocs64;
+#endif
+
+struct section {
+	Elf_Shdr       shdr;
+	struct section *link;
+	Elf_Sym        *symtab;
+	Elf_Rel        *reltab;
+	char           *strtab;
+};
+static struct section *secs;
+
+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] =
+	"^(__init_(begin|end)|"
+	"__x86_cpu_dev_(start|end)|"
+	"(__parainstructions|__alt_instructions)(|_end)|"
+	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
+	"__(start|end)_pci_.*|"
+	"__(start|end)_builtin_fw|"
+	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
+	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
+	"__(start|stop)___param|"
+	"__(start|stop)___modver|"
+	"__(start|stop)___bug_table|"
+	"__tracedata_(start|end)|"
+	"__(start|stop)_notes|"
+	"__end_rodata|"
+	"__end_rodata_aligned|"
+	"__initramfs_start|"
+	"(jiffies|jiffies_64)|"
+#if ELF_BITS == 64
+	"__per_cpu_load|"
+	"init_per_cpu__.*|"
+	"__end_rodata_hpage_align|"
+#endif
+	"__vvar_page|"
+	"_end)$"
+};
+
+
+static const char * const sym_regex_realmode[S_NSYMTYPES] = {
+/*
+ * These symbols are known to be relative, even if the linker marks them
+ * as absolute (typically defined outside any section in the linker script.)
+ */
+	[S_REL] =
+	"^pa_",
+
+/*
+ * These are 16-bit segment symbols when compiling 16-bit code.
+ */
+	[S_SEG] =
+	"^real_mode_seg$",
+
+/*
+ * 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 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
+#if ELF_BITS == 64
+		REL_TYPE(R_X86_64_NONE),
+		REL_TYPE(R_X86_64_64),
+		REL_TYPE(R_X86_64_PC32),
+		REL_TYPE(R_X86_64_GOT32),
+		REL_TYPE(R_X86_64_PLT32),
+		REL_TYPE(R_X86_64_COPY),
+		REL_TYPE(R_X86_64_GLOB_DAT),
+		REL_TYPE(R_X86_64_JUMP_SLOT),
+		REL_TYPE(R_X86_64_RELATIVE),
+		REL_TYPE(R_X86_64_GOTPCREL),
+		REL_TYPE(R_X86_64_32),
+		REL_TYPE(R_X86_64_32S),
+		REL_TYPE(R_X86_64_16),
+		REL_TYPE(R_X86_64_PC16),
+		REL_TYPE(R_X86_64_8),
+		REL_TYPE(R_X86_64_PC8),
+#else
+		REL_TYPE(R_386_NONE),
+		REL_TYPE(R_386_32),
+		REL_TYPE(R_386_PC32),
+		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),
+#endif
+#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, Elf_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;
+}
+
+static Elf_Sym *sym_lookup(const char *symname)
+{
+	int i;
+	for (i = 0; i < ehdr.e_shnum; i++) {
+		struct section *sec = &secs[i];
+		long nsyms;
+		char *strtab;
+		Elf_Sym *symtab;
+		Elf_Sym *sym;
+
+		if (sec->shdr.sh_type != SHT_SYMTAB)
+			continue;
+
+		nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
+		symtab = sec->symtab;
+		strtab = sec->link->strtab;
+
+		for (sym = symtab; --nsyms >= 0; sym++) {
+			if (!sym->st_name)
+				continue;
+			if (strcmp(symname, strtab + sym->st_name) == 0)
+				return sym;
+		}
+	}
+	return 0;
+}
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define le16_to_cpu(val) (val)
+#define le32_to_cpu(val) (val)
+#define le64_to_cpu(val) (val)
+#endif
+#if BYTE_ORDER == BIG_ENDIAN
+#define le16_to_cpu(val) bswap_16(val)
+#define le32_to_cpu(val) bswap_32(val)
+#define le64_to_cpu(val) bswap_64(val)
+#endif
+
+static uint16_t elf16_to_cpu(uint16_t val)
+{
+	return le16_to_cpu(val);
+}
+
+static uint32_t elf32_to_cpu(uint32_t val)
+{
+	return le32_to_cpu(val);
+}
+
+#define elf_half_to_cpu(x)	elf16_to_cpu(x)
+#define elf_word_to_cpu(x)	elf32_to_cpu(x)
+
+#if ELF_BITS == 64
+static uint64_t elf64_to_cpu(uint64_t val)
+{
+        return le64_to_cpu(val);
+}
+#define elf_addr_to_cpu(x)	elf64_to_cpu(x)
+#define elf_off_to_cpu(x)	elf64_to_cpu(x)
+#define elf_xword_to_cpu(x)	elf64_to_cpu(x)
+#else
+#define elf_addr_to_cpu(x)	elf32_to_cpu(x)
+#define elf_off_to_cpu(x)	elf32_to_cpu(x)
+#define elf_xword_to_cpu(x)	elf32_to_cpu(x)
+#endif
+
+static void read_ehdr(FILE *fp)
+{
+	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
+		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] != ELF_CLASS) {
+		die("Not a %d bit executable\n", ELF_BITS);
+	}
+	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
+		die("Not a LSB ELF executable\n");
+	}
+	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
+		die("Unknown ELF version\n");
+	}
+	/* Convert the fields to native endian */
+	ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
+	ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
+	ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
+	ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
+	ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
+	ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
+	ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
+	ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
+	ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
+	ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
+	ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
+	ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
+	ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);
+
+	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
+		die("Unsupported ELF header type\n");
+	}
+	if (ehdr.e_machine != ELF_MACHINE) {
+		die("Not for %s\n", ELF_MACHINE_NAME);
+	}
+	if (ehdr.e_version != EV_CURRENT) {
+		die("Unknown ELF version\n");
+	}
+	if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
+		die("Bad Elf header size\n");
+	}
+	if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
+		die("Bad program header entry\n");
+	}
+	if (ehdr.e_shentsize != sizeof(Elf_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;
+	Elf_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      = elf_word_to_cpu(shdr.sh_name);
+		sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
+		sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
+		sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
+		sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
+		sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
+		sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
+		sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
+		sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
+		sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
+		if (sec->shdr.sh_link < ehdr.e_shnum)
+			sec->link = &secs[sec->shdr.sh_link];
+	}
+
+}
+
+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(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;
+static 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:
+		/* NONE can be ignored. */
+		break;
+
+	case R_X86_64_PC32:
+	case R_X86_64_PLT32:
+		/*
+		 * PC relative relocations don't need to be adjusted unless
+		 * referencing a percpu symbol.
+		 *
+		 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
+		 */
+		if (is_percpu_sym(sym, symname))
+			add_reloc(&relocs32neg, offset);
+		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:
+	case R_386_PLT32:
+		/*
+		 * NONE can be ignored and PC relative relocations don't need
+		 * to be adjusted. Because sym must be defined, R_386_PLT32 can
+		 * be treated the same way as R_386_PC32.
+		 */
+		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:
+	case R_386_PLT32:
+		/*
+		 * NONE can be ignored and PC relative relocations don't need
+		 * to be adjusted. Because sym must be defined, R_386_PLT32 can
+		 * be treated the same way as R_386_PC32.
+		 */
+		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(&relocs32);
+#if ELF_BITS == 64
+	sort_relocs(&relocs32neg);
+	sort_relocs(&relocs64);
+#else
+	sort_relocs(&relocs16);
+#endif
+
+	/* 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 inverse 32-bit relocation */
+		for (i = 0; i < relocs32neg.count; i++)
+			write_reloc(relocs32neg.offset[i], stdout);
+#endif
+
+		/* 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);
+}