[linux-2.6-block.git] / arch / x86 / boot / compressed / relocs.c

#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>

#define MAX_SHDRS 100
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
static Elf32_Ehdr ehdr;
static Elf32_Shdr shdr[MAX_SHDRS];
static Elf32_Sym  *symtab[MAX_SHDRS];
static Elf32_Rel  *reltab[MAX_SHDRS];
static char *strtab[MAX_SHDRS];
static unsigned long reloc_count, reloc_idx;
static unsigned long *relocs;

/*
 * 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* safe_abs_relocs[] = {
		"xen_irq_disable_direct_reloc",
		"xen_save_fl_direct_reloc",
};

static int is_safe_abs_reloc(const char* sym_name)
{
	int i;

	for(i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
		if (!strcmp(sym_name, safe_abs_relocs[i]))
			/* Match found */
			return 1;
	}
	if (strncmp(sym_name, "VDSO", 4) == 0)
		return 1;
	if (strncmp(sym_name, "__crc_", 6) == 0)
		return 1;
	return 0;
}

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)) {
		name = type_name[type];
	}
	return name;
}

static const char *sec_name(unsigned shndx)
{
	const char *sec_strtab;
	const char *name;
	sec_strtab = strtab[ehdr.e_shstrndx];
	name = "<noname>";
	if (shndx < ehdr.e_shnum) {
		name = sec_strtab + shdr[shndx].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(shdr[sym->st_shndx].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;
	if (ehdr.e_shnum > MAX_SHDRS) {
		die("%d section headers supported: %d\n",
			ehdr.e_shnum, MAX_SHDRS);
	}
	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
		die("Seek to %d failed: %s\n",
			ehdr.e_shoff, strerror(errno));
	}
	if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
		die("Cannot read ELF section headers: %s\n",
			strerror(errno));
	}
	for(i = 0; i < ehdr.e_shnum; i++) {
		shdr[i].sh_name      = elf32_to_cpu(shdr[i].sh_name);
		shdr[i].sh_type      = elf32_to_cpu(shdr[i].sh_type);
		shdr[i].sh_flags     = elf32_to_cpu(shdr[i].sh_flags);
		shdr[i].sh_addr      = elf32_to_cpu(shdr[i].sh_addr);
		shdr[i].sh_offset    = elf32_to_cpu(shdr[i].sh_offset);
		shdr[i].sh_size      = elf32_to_cpu(shdr[i].sh_size);
		shdr[i].sh_link      = elf32_to_cpu(shdr[i].sh_link);
		shdr[i].sh_info      = elf32_to_cpu(shdr[i].sh_info);
		shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
		shdr[i].sh_entsize   = elf32_to_cpu(shdr[i].sh_entsize);
	}

}

static void read_strtabs(FILE *fp)
{
	int i;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_STRTAB) {
			continue;
		}
		strtab[i] = malloc(shdr[i].sh_size);
		if (!strtab[i]) {
			die("malloc of %d bytes for strtab failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].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++) {
		if (shdr[i].sh_type != SHT_SYMTAB) {
			continue;
		}
		symtab[i] = malloc(shdr[i].sh_size);
		if (!symtab[i]) {
			die("malloc of %d bytes for symtab failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
			symtab[i][j].st_name  = elf32_to_cpu(symtab[i][j].st_name);
			symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
			symtab[i][j].st_size  = elf32_to_cpu(symtab[i][j].st_size);
			symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
		}
	}
}


static void read_relocs(FILE *fp)
{
	int i,j;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		reltab[i] = malloc(shdr[i].sh_size);
		if (!reltab[i]) {
			die("malloc of %d bytes for relocs failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
			reltab[i][j].r_info   = elf32_to_cpu(reltab[i][j].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++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		int j;
		if (shdr[i].sh_type != SHT_SYMTAB) {
			continue;
		}
		sh_symtab = symtab[i];
		sym_strtab = strtab[shdr[i].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
			Elf32_Sym *sym;
			const char *name;
			sym = &symtab[i][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++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		unsigned sec_applies, sec_symtab;
		int j;
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = shdr[i].sh_link;
		sec_applies = shdr[i].sh_info;
		if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = symtab[sec_symtab];
		sym_strtab = strtab[shdr[sec_symtab].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			const char *name;
			rel = &reltab[i][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_safe_abs_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;
		unsigned sec_applies, sec_symtab;
		int j;
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = shdr[i].sh_link;
		sec_applies = shdr[i].sh_info;
		if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = symtab[sec_symtab];
		sym_strtab = strtab[shdr[sec_symtab].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			unsigned r_type;
			rel = &reltab[i][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) {
				continue;
			}
			if (r_type == R_386_PC32) {
				/* PC relative relocations don't need to be adjusted */
			}
			else if (r_type == R_386_32) {
				/* Visit relocations that need to be adjusted */
				visit(rel, sym);
			}
			else {
				die("Unsupported relocation type: %d\n", r_type);
			}
		}
	}
}

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];
		buf[0] = buf[1] = buf[2] = buf[3] = 0;
		/* Print a stop */
		printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
		/* Now print each relocation */
		for(i = 0; i < reloc_count; i++) {
			buf[0] = (relocs[i] >>  0) & 0xff;
			buf[1] = (relocs[i] >>  8) & 0xff;
			buf[2] = (relocs[i] >> 16) & 0xff;
			buf[3] = (relocs[i] >> 24) & 0xff;
			printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
		}
	}
}

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;

	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;
}
Commit	Line	Data
968de4f0 EB	1	#include <stdio.h>
	2	#include <stdarg.h>
	3	#include <stdlib.h>
	4	#include <stdint.h>
	5	#include <string.h>
	6	#include <errno.h>
	7	#include <unistd.h>
	8	#include <elf.h>
	9	#include <byteswap.h>
	10	#define USE_BSD
	11	#include <endian.h>
	12
	13	#define MAX_SHDRS 100
ca820181	14	#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
968de4f0 EB	15	static Elf32_Ehdr ehdr;
	16	static Elf32_Shdr shdr[MAX_SHDRS];
	17	static Elf32_Sym *symtab[MAX_SHDRS];
	18	static Elf32_Rel *reltab[MAX_SHDRS];
	19	static char *strtab[MAX_SHDRS];
	20	static unsigned long reloc_count, reloc_idx;
	21	static unsigned long *relocs;
	22
6a044b3a VG	23	/*
	24	* Following symbols have been audited. There values are constant and do
	25	* not change if bzImage is loaded at a different physical address than
	26	* the address for which it has been compiled. Don't warn user about
	27	* absolute relocations present w.r.t these symbols.
	28	*/
	29	static const char* safe_abs_relocs[] = {
600b2fc2 JF	30	"xen_irq_disable_direct_reloc",
600b2fc2 JF	31	"xen_save_fl_direct_reloc",
6a044b3a VG	32	};
	33
	34	static int is_safe_abs_reloc(const char* sym_name)
	35	{
4d022ada	36	int i;
6a044b3a	37
4d022ada	38	for(i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
6a044b3a VG	39	if (!strcmp(sym_name, safe_abs_relocs[i]))
	40	/* Match found */
	41	return 1;
	42	}
4707c471 RM	43	if (strncmp(sym_name, "VDSO", 4) == 0)
4707c471 RM	44	return 1;
2a3d4f1f AV	45	if (strncmp(sym_name, "__crc_", 6) == 0)
2a3d4f1f AV	46	return 1;
6a044b3a VG	47	return 0;
	48	}
	49
968de4f0 EB	50	static void die(char *fmt, ...)
	51	{
	52	va_list ap;
	53	va_start(ap, fmt);
	54	vfprintf(stderr, fmt, ap);
	55	va_end(ap);
	56	exit(1);
	57	}
	58
	59	static const char *sym_type(unsigned type)
	60	{
	61	static const char *type_name[] = {
	62	#define SYM_TYPE(X) [X] = #X
	63	SYM_TYPE(STT_NOTYPE),
	64	SYM_TYPE(STT_OBJECT),
	65	SYM_TYPE(STT_FUNC),
	66	SYM_TYPE(STT_SECTION),
	67	SYM_TYPE(STT_FILE),
	68	SYM_TYPE(STT_COMMON),
	69	SYM_TYPE(STT_TLS),
	70	#undef SYM_TYPE
	71	};
	72	const char *name = "unknown sym type name";
ca820181	73	if (type < ARRAY_SIZE(type_name)) {
968de4f0 EB	74	name = type_name[type];
	75	}
	76	return name;
	77	}
	78
	79	static const char *sym_bind(unsigned bind)
	80	{
	81	static const char *bind_name[] = {
	82	#define SYM_BIND(X) [X] = #X
	83	SYM_BIND(STB_LOCAL),
	84	SYM_BIND(STB_GLOBAL),
	85	SYM_BIND(STB_WEAK),
	86	#undef SYM_BIND
	87	};
	88	const char *name = "unknown sym bind name";
ca820181	89	if (bind < ARRAY_SIZE(bind_name)) {
968de4f0 EB	90	name = bind_name[bind];
	91	}
	92	return name;
	93	}
	94
	95	static const char *sym_visibility(unsigned visibility)
	96	{
	97	static const char *visibility_name[] = {
	98	#define SYM_VISIBILITY(X) [X] = #X
	99	SYM_VISIBILITY(STV_DEFAULT),
	100	SYM_VISIBILITY(STV_INTERNAL),
	101	SYM_VISIBILITY(STV_HIDDEN),
	102	SYM_VISIBILITY(STV_PROTECTED),
	103	#undef SYM_VISIBILITY
	104	};
	105	const char *name = "unknown sym visibility name";
ca820181	106	if (visibility < ARRAY_SIZE(visibility_name)) {
968de4f0 EB	107	name = visibility_name[visibility];
	108	}
	109	return name;
	110	}
	111
	112	static const char *rel_type(unsigned type)
	113	{
	114	static const char *type_name[] = {
	115	#define REL_TYPE(X) [X] = #X
	116	REL_TYPE(R_386_NONE),
	117	REL_TYPE(R_386_32),
	118	REL_TYPE(R_386_PC32),
	119	REL_TYPE(R_386_GOT32),
	120	REL_TYPE(R_386_PLT32),
	121	REL_TYPE(R_386_COPY),
	122	REL_TYPE(R_386_GLOB_DAT),
	123	REL_TYPE(R_386_JMP_SLOT),
	124	REL_TYPE(R_386_RELATIVE),
	125	REL_TYPE(R_386_GOTOFF),
	126	REL_TYPE(R_386_GOTPC),
	127	#undef REL_TYPE
	128	};
	129	const char *name = "unknown type rel type name";
ca820181	130	if (type < ARRAY_SIZE(type_name)) {
968de4f0 EB	131	name = type_name[type];
	132	}
	133	return name;
	134	}
	135
	136	static const char *sec_name(unsigned shndx)
	137	{
	138	const char *sec_strtab;
	139	const char *name;
	140	sec_strtab = strtab[ehdr.e_shstrndx];
	141	name = "<noname>";
	142	if (shndx < ehdr.e_shnum) {
	143	name = sec_strtab + shdr[shndx].sh_name;
	144	}
	145	else if (shndx == SHN_ABS) {
	146	name = "ABSOLUTE";
	147	}
	148	else if (shndx == SHN_COMMON) {
	149	name = "COMMON";
	150	}
	151	return name;
	152	}
	153
	154	static const char sym_name(const char sym_strtab, Elf32_Sym *sym)
	155	{
	156	const char *name;
	157	name = "<noname>";
	158	if (sym->st_name) {
	159	name = sym_strtab + sym->st_name;
	160	}
	161	else {
	162	name = sec_name(shdr[sym->st_shndx].sh_name);
	163	}
	164	return name;
	165	}
	166
	167
	168
	169	#if BYTE_ORDER == LITTLE_ENDIAN
	170	#define le16_to_cpu(val) (val)
	171	#define le32_to_cpu(val) (val)
	172	#endif
	173	#if BYTE_ORDER == BIG_ENDIAN
	174	#define le16_to_cpu(val) bswap_16(val)
	175	#define le32_to_cpu(val) bswap_32(val)
	176	#endif
	177
	178	static uint16_t elf16_to_cpu(uint16_t val)
	179	{
	180	return le16_to_cpu(val);
	181	}
	182
	183	static uint32_t elf32_to_cpu(uint32_t val)
	184	{
	185	return le32_to_cpu(val);
	186	}
	187
	188	static void read_ehdr(FILE *fp)
	189	{
	190	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
	191	die("Cannot read ELF header: %s\n",
	192	strerror(errno));
	193	}
8bd1796d	194	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
968de4f0 EB	195	die("No ELF magic\n");
	196	}
	197	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
	198	die("Not a 32 bit executable\n");
	199	}
	200	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
	201	die("Not a LSB ELF executable\n");
	202	}
	203	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
	204	die("Unknown ELF version\n");
	205	}
	206	/* Convert the fields to native endian */
	207	ehdr.e_type = elf16_to_cpu(ehdr.e_type);
	208	ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
	209	ehdr.e_version = elf32_to_cpu(ehdr.e_version);
	210	ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
	211	ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
	212	ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
	213	ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
	214	ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
	215	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
	216	ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
	217	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
	218	ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
	219	ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
	220
	221	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
	222	die("Unsupported ELF header type\n");
	223	}
	224	if (ehdr.e_machine != EM_386) {
	225	die("Not for x86\n");
	226	}
	227	if (ehdr.e_version != EV_CURRENT) {
	228	die("Unknown ELF version\n");
	229	}
	230	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
	231	die("Bad Elf header size\n");
	232	}
	233	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
	234	die("Bad program header entry\n");
	235	}
	236	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
	237	die("Bad section header entry\n");
	238	}
	239	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
	240	die("String table index out of bounds\n");
	241	}
	242	}
	243
	244	static void read_shdrs(FILE *fp)
	245	{
	246	int i;
	247	if (ehdr.e_shnum > MAX_SHDRS) {
	248	die("%d section headers supported: %d\n",
	249	ehdr.e_shnum, MAX_SHDRS);
	250	}
	251	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
	252	die("Seek to %d failed: %s\n",
	253	ehdr.e_shoff, strerror(errno));
	254	}
	255	if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
	256	die("Cannot read ELF section headers: %s\n",
	257	strerror(errno));
	258	}
259	for(i = 0; i < ehdr.e_shnum; i++) {
260	shdr[i].sh_name = elf32_to_cpu(shdr[i].sh_name);
261	shdr[i].sh_type = elf32_to_cpu(shdr[i].sh_type);
262	shdr[i].sh_flags = elf32_to_cpu(shdr[i].sh_flags);
263	shdr[i].sh_addr = elf32_to_cpu(shdr[i].sh_addr);
264	shdr[i].sh_offset = elf32_to_cpu(shdr[i].sh_offset);
265	shdr[i].sh_size = elf32_to_cpu(shdr[i].sh_size);
266	shdr[i].sh_link = elf32_to_cpu(shdr[i].sh_link);
267	shdr[i].sh_info = elf32_to_cpu(shdr[i].sh_info);
268	shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
269	shdr[i].sh_entsize = elf32_to_cpu(shdr[i].sh_entsize);
270	}
271
272	}
273
274	static void read_strtabs(FILE *fp)
275	{
276	int i;
277	for(i = 0; i < ehdr.e_shnum; i++) {
278	if (shdr[i].sh_type != SHT_STRTAB) {
279	continue;
280	}
281	strtab[i] = malloc(shdr[i].sh_size);
282	if (!strtab[i]) {
283	die("malloc of %d bytes for strtab failed\n",
284	shdr[i].sh_size);
285	}
286	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
287	die("Seek to %d failed: %s\n",
288	shdr[i].sh_offset, strerror(errno));
289	}
290	if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
291	die("Cannot read symbol table: %s\n",
292	strerror(errno));
293	}
294	}
295	}
296
297	static void read_symtabs(FILE *fp)
298	{
299	int i,j;
300	for(i = 0; i < ehdr.e_shnum; i++) {
301	if (shdr[i].sh_type != SHT_SYMTAB) {
302	continue;
303	}
304	symtab[i] = malloc(shdr[i].sh_size);
305	if (!symtab[i]) {
306	die("malloc of %d bytes for symtab failed\n",
307	shdr[i].sh_size);
308	}
309	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
310	die("Seek to %d failed: %s\n",
311	shdr[i].sh_offset, strerror(errno));
312	}
313	if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
314	die("Cannot read symbol table: %s\n",
315	strerror(errno));
316	}
317	for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
318	symtab[i][j].st_name = elf32_to_cpu(symtab[i][j].st_name);
319	symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
320	symtab[i][j].st_size = elf32_to_cpu(symtab[i][j].st_size);
321	symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
322	}
323	}
324	}
325
326
327	static void read_relocs(FILE *fp)
328	{
329	int i,j;
330	for(i = 0; i < ehdr.e_shnum; i++) {
331	if (shdr[i].sh_type != SHT_REL) {
332	continue;
333	}
334	reltab[i] = malloc(shdr[i].sh_size);
335	if (!reltab[i]) {
336	die("malloc of %d bytes for relocs failed\n",
337	shdr[i].sh_size);
338	}
339	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
340	die("Seek to %d failed: %s\n",
341	shdr[i].sh_offset, strerror(errno));
342	}
343	if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
344	die("Cannot read symbol table: %s\n",
345	strerror(errno));
346	}
347	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
348	reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
349	reltab[i][j].r_info = elf32_to_cpu(reltab[i][j].r_info);
350	}
351	}
352	}
353
354
355	static void print_absolute_symbols(void)
356	{
357	int i;
358	printf("Absolute symbols\n");
359	printf(" Num: Value Size Type Bind Visibility Name\n");
360	for(i = 0; i < ehdr.e_shnum; i++) {
361	char *sym_strtab;
362	Elf32_Sym *sh_symtab;
363	int j;
364	if (shdr[i].sh_type != SHT_SYMTAB) {
365	continue;
366	}
367	sh_symtab = symtab[i];
368	sym_strtab = strtab[shdr[i].sh_link];
369	for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
370	Elf32_Sym *sym;
371	const char *name;
372	sym = &symtab[i][j];
373	name = sym_name(sym_strtab, sym);
374	if (sym->st_shndx != SHN_ABS) {
375	continue;
376	}
377	printf("%5d %08x %5d %10s %10s %12s %s\n",
378	j, sym->st_value, sym->st_size,
379	sym_type(ELF32_ST_TYPE(sym->st_info)),
380	sym_bind(ELF32_ST_BIND(sym->st_info)),
381	sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
382	name);
383	}
384	}
385	printf("\n");
386	}
387
388	static void print_absolute_relocs(void)
389	{
6a044b3a VG	390	int i, printed = 0;
6a044b3a VG	391
968de4f0 EB	392	for(i = 0; i < ehdr.e_shnum; i++) {
	393	char *sym_strtab;
	394	Elf32_Sym *sh_symtab;
	395	unsigned sec_applies, sec_symtab;
	396	int j;
	397	if (shdr[i].sh_type != SHT_REL) {
	398	continue;
	399	}
	400	sec_symtab = shdr[i].sh_link;
	401	sec_applies = shdr[i].sh_info;
	402	if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
	403	continue;
	404	}
	405	sh_symtab = symtab[sec_symtab];
	406	sym_strtab = strtab[shdr[sec_symtab].sh_link];
	407	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
	408	Elf32_Rel *rel;
	409	Elf32_Sym *sym;
	410	const char *name;
	411	rel = &reltab[i][j];
	412	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
	413	name = sym_name(sym_strtab, sym);
	414	if (sym->st_shndx != SHN_ABS) {
	415	continue;
	416	}
6a044b3a VG	417
	418	/* Absolute symbols are not relocated if bzImage is
	419	* loaded at a non-compiled address. Display a warning
	420	* to user at compile time about the absolute
	421	* relocations present.
	422	*
	423	* User need to audit the code to make sure
	424	* some symbols which should have been section
	425	* relative have not become absolute because of some
	426	* linker optimization or wrong programming usage.
	427	*
	428	* Before warning check if this absolute symbol
	429	* relocation is harmless.
	430	*/
	431	if (is_safe_abs_reloc(name))
	432	continue;
	433
	434	if (!printed) {
	435	printf("WARNING: Absolute relocations"
	436	" present\n");
	437	printf("Offset Info Type Sym.Value "
	438	"Sym.Name\n");
	439	printed = 1;
	440	}
	441
968de4f0 EB	442	printf("%08x %08x %10s %08x %s\n",
	443	rel->r_offset,
	444	rel->r_info,
	445	rel_type(ELF32_R_TYPE(rel->r_info)),
	446	sym->st_value,
	447	name);
	448	}
	449	}
6a044b3a VG	450
	451	if (printed)
	452	printf("\n");
968de4f0 EB	453	}
	454
	455	static void walk_relocs(void (visit)(Elf32_Rel rel, Elf32_Sym *sym))
	456	{
	457	int i;
	458	/* Walk through the relocations */
	459	for(i = 0; i < ehdr.e_shnum; i++) {
	460	char *sym_strtab;
	461	Elf32_Sym *sh_symtab;
	462	unsigned sec_applies, sec_symtab;
	463	int j;
	464	if (shdr[i].sh_type != SHT_REL) {
	465	continue;
	466	}
	467	sec_symtab = shdr[i].sh_link;
	468	sec_applies = shdr[i].sh_info;
	469	if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
	470	continue;
	471	}
	472	sh_symtab = symtab[sec_symtab];
	473	sym_strtab = strtab[shdr[sec_symtab].sh_link];
	474	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
	475	Elf32_Rel *rel;
	476	Elf32_Sym *sym;
	477	unsigned r_type;
	478	rel = &reltab[i][j];
	479	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
	480	r_type = ELF32_R_TYPE(rel->r_info);
	481	/* Don't visit relocations to absolute symbols */
	482	if (sym->st_shndx == SHN_ABS) {
	483	continue;
	484	}
	485	if (r_type == R_386_PC32) {
	486	/* PC relative relocations don't need to be adjusted */
	487	}
	488	else if (r_type == R_386_32) {
	489	/* Visit relocations that need to be adjusted */
	490	visit(rel, sym);
	491	}
	492	else {
	493	die("Unsupported relocation type: %d\n", r_type);
	494	}
	495	}
	496	}
	497	}
	498
	499	static void count_reloc(Elf32_Rel rel, Elf32_Sym sym)
	500	{
	501	reloc_count += 1;
	502	}
	503
	504	static void collect_reloc(Elf32_Rel rel, Elf32_Sym sym)
	505	{
	506	/* Remember the address that needs to be adjusted. */
	507	relocs[reloc_idx++] = rel->r_offset;
	508	}
	509
	510	static int cmp_relocs(const void va, const void vb)
	511	{
	512	const unsigned long a, b;
	513	a = va; b = vb;
	514	return (a == b)? 0 : (a > b)? 1 : -1;
	515	}
	516
517	static void emit_relocs(int as_text)
518	{
519	int i;
520	/* Count how many relocations I have and allocate space for them. */
521	reloc_count = 0;
522	walk_relocs(count_reloc);
523	relocs = malloc(reloc_count * sizeof(relocs[0]));
524	if (!relocs) {
525	die("malloc of %d entries for relocs failed\n",
526	reloc_count);
527	}
528	/* Collect up the relocations */
529	reloc_idx = 0;
530	walk_relocs(collect_reloc);
531
532	/* Order the relocations for more efficient processing */
533	qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
534
535	/* Print the relocations */
536	if (as_text) {
537	/* Print the relocations in a form suitable that
538	* gas will like.
539	*/
540	printf(".section \".data.reloc\",\"a\"\n");
541	printf(".balign 4\n");
542	for(i = 0; i < reloc_count; i++) {
543	printf("\t .long 0x%08lx\n", relocs[i]);
544	}
545	printf("\n");
546	}
547	else {
548	unsigned char buf[4];
549	buf[0] = buf[1] = buf[2] = buf[3] = 0;
550	/* Print a stop */
551	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
552	/* Now print each relocation */
553	for(i = 0; i < reloc_count; i++) {
554	buf[0] = (relocs[i] >> 0) & 0xff;
555	buf[1] = (relocs[i] >> 8) & 0xff;
556	buf[2] = (relocs[i] >> 16) & 0xff;
557	buf[3] = (relocs[i] >> 24) & 0xff;
558	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
559	}
560	}
561	}
562
563	static void usage(void)
564	{
6a044b3a	565	die("relocs [--abs-syms \|--abs-relocs \| --text] vmlinux\n");
968de4f0 EB	566	}
	567
	568	int main(int argc, char **argv)
	569	{
6a044b3a	570	int show_absolute_syms, show_absolute_relocs;
968de4f0 EB	571	int as_text;
	572	const char *fname;
	573	FILE *fp;
	574	int i;
	575
6a044b3a VG	576	show_absolute_syms = 0;
6a044b3a VG	577	show_absolute_relocs = 0;
968de4f0 EB	578	as_text = 0;
	579	fname = NULL;
	580	for(i = 1; i < argc; i++) {
	581	char *arg = argv[i];
	582	if (*arg == '-') {
6a044b3a VG	583	if (strcmp(argv[1], "--abs-syms") == 0) {
	584	show_absolute_syms = 1;
	585	continue;
	586	}
	587
	588	if (strcmp(argv[1], "--abs-relocs") == 0) {
	589	show_absolute_relocs = 1;
968de4f0 EB	590	continue;
	591	}
	592	else if (strcmp(argv[1], "--text") == 0) {
	593	as_text = 1;
	594	continue;
	595	}
	596	}
	597	else if (!fname) {
	598	fname = arg;
	599	continue;
	600	}
	601	usage();
	602	}
	603	if (!fname) {
	604	usage();
	605	}
	606	fp = fopen(fname, "r");
	607	if (!fp) {
	608	die("Cannot open %s: %s\n",
	609	fname, strerror(errno));
	610	}
	611	read_ehdr(fp);
	612	read_shdrs(fp);
	613	read_strtabs(fp);
	614	read_symtabs(fp);
	615	read_relocs(fp);
6a044b3a	616	if (show_absolute_syms) {
968de4f0	617	print_absolute_symbols();
6a044b3a VG	618	return 0;
	619	}
	620	if (show_absolute_relocs) {
968de4f0 EB	621	print_absolute_relocs();
	622	return 0;
	623	}
	624	emit_relocs(as_text);
	625	return 0;
	626	}