[deliverable/linux.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 ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
static Elf32_Ehdr ehdr;
static unsigned long reloc_count, reloc_idx;
static unsigned long *relocs;

struct section {
	Elf32_Shdr     shdr;
	struct section *link;
	Elf32_Sym      *symtab;
	Elf32_Rel      *reltab;
	char           *strtab;
};
static struct section *secs;

/*
 * Following symbols have been audited. There values are constant and do
 * not change if bzImage is loaded at a different physical address than
 * the address for which it has been compiled. Don't warn user about
 * absolute relocations present w.r.t these symbols.
 */
static const char* 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 = secs[ehdr.e_shstrndx].strtab;
	name = "<noname>";
	if (shndx < ehdr.e_shnum) {
		name = sec_strtab + secs[shndx].shdr.sh_name;
	}
	else if (shndx == SHN_ABS) {
		name = "ABSOLUTE";
	}
	else if (shndx == SHN_COMMON) {
		name = "COMMON";
	}
	return name;
}

static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
{
	const char *name;
	name = "<noname>";
	if (sym->st_name) {
		name = sym_strtab + sym->st_name;
	}
	else {
		name = sec_name(secs[sym->st_shndx].shdr.sh_name);
	}
	return name;
}


#if BYTE_ORDER == LITTLE_ENDIAN
#define le16_to_cpu(val) (val)
#define le32_to_cpu(val) (val)
#endif
#if BYTE_ORDER == BIG_ENDIAN
#define le16_to_cpu(val) bswap_16(val)
#define le32_to_cpu(val) bswap_32(val)
#endif

static uint16_t elf16_to_cpu(uint16_t val)
{
	return le16_to_cpu(val);
}

static uint32_t elf32_to_cpu(uint32_t val)
{
	return le32_to_cpu(val);
}

static void read_ehdr(FILE *fp)
{
	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
		die("Cannot read ELF header: %s\n",
			strerror(errno));
	}
	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
		die("No ELF magic\n");
	}
	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
		die("Not a 32 bit executable\n");
	}
	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
		die("Not a LSB ELF executable\n");
	}
	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
		die("Unknown ELF version\n");
	}
	/* Convert the fields to native endian */
	ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
	ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
	ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
	ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
	ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
	ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
	ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
	ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
	ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
	ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
	ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);

	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
		die("Unsupported ELF header type\n");
	}
	if (ehdr.e_machine != EM_386) {
		die("Not for x86\n");
	}
	if (ehdr.e_version != EV_CURRENT) {
		die("Unknown ELF version\n");
	}
	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
		die("Bad Elf header size\n");
	}
	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
		die("Bad program header entry\n");
	}
	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
		die("Bad section header entry\n");
	}
	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
		die("String table index out of bounds\n");
	}
}

static void read_shdrs(FILE *fp)
{
	int i;
	Elf32_Shdr shdr;

	secs = calloc(ehdr.e_shnum, sizeof(struct section));
	if (!secs) {
		die("Unable to allocate %d section headers\n",
		    ehdr.e_shnum);
	}
	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
		die("Seek to %d failed: %s\n",
			ehdr.e_shoff, strerror(errno));
	}
	for (i = 0; i < ehdr.e_shnum; i++) {
		struct section *sec = &secs[i];
		if (fread(&shdr, sizeof shdr, 1, fp) != 1)
			die("Cannot read ELF section headers %d/%d: %s\n",
			    i, ehdr.e_shnum, strerror(errno));
		sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
		sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
		sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
		sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
		sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
		sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
		sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
		sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
		sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
		sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
		if (sec->shdr.sh_link < ehdr.e_shnum)
			sec->link = &secs[sec->shdr.sh_link];
	}

}

static void read_strtabs(FILE *fp)
{
	int i;
	for (i = 0; i < ehdr.e_shnum; i++) {
		struct section *sec = &secs[i];
		if (sec->shdr.sh_type != SHT_STRTAB) {
			continue;
		}
		sec->strtab = malloc(sec->shdr.sh_size);
		if (!sec->strtab) {
			die("malloc of %d bytes for strtab failed\n",
				sec->shdr.sh_size);
		}
		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				sec->shdr.sh_offset, strerror(errno));
		}
		if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
		    != sec->shdr.sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
	}
}

static void read_symtabs(FILE *fp)
{
	int i,j;
	for (i = 0; i < ehdr.e_shnum; i++) {
		struct section *sec = &secs[i];
		if (sec->shdr.sh_type != SHT_SYMTAB) {
			continue;
		}
		sec->symtab = malloc(sec->shdr.sh_size);
		if (!sec->symtab) {
			die("malloc of %d bytes for symtab failed\n",
				sec->shdr.sh_size);
		}
		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				sec->shdr.sh_offset, strerror(errno));
		}
		if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
		    != sec->shdr.sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
			Elf32_Sym *sym = &sec->symtab[j];
			sym->st_name  = elf32_to_cpu(sym->st_name);
			sym->st_value = elf32_to_cpu(sym->st_value);
			sym->st_size  = elf32_to_cpu(sym->st_size);
			sym->st_shndx = elf16_to_cpu(sym->st_shndx);
		}
	}
}


static void read_relocs(FILE *fp)
{
	int i,j;
	for (i = 0; i < ehdr.e_shnum; i++) {
		struct section *sec = &secs[i];
		if (sec->shdr.sh_type != SHT_REL) {
			continue;
		}
		sec->reltab = malloc(sec->shdr.sh_size);
		if (!sec->reltab) {
			die("malloc of %d bytes for relocs failed\n",
				sec->shdr.sh_size);
		}
		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				sec->shdr.sh_offset, strerror(errno));
		}
		if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
		    != sec->shdr.sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
			Elf32_Rel *rel = &sec->reltab[j];
			rel->r_offset = elf32_to_cpu(rel->r_offset);
			rel->r_info   = elf32_to_cpu(rel->r_info);
		}
	}
}


static void print_absolute_symbols(void)
{
	int i;
	printf("Absolute symbols\n");
	printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
	for (i = 0; i < ehdr.e_shnum; i++) {
		struct section *sec = &secs[i];
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		int j;

		if (sec->shdr.sh_type != SHT_SYMTAB) {
			continue;
		}
		sh_symtab = sec->symtab;
		sym_strtab = sec->link->strtab;
		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
			Elf32_Sym *sym;
			const char *name;
			sym = &sec->symtab[j];
			name = sym_name(sym_strtab, sym);
			if (sym->st_shndx != SHN_ABS) {
				continue;
			}
			printf("%5d %08x %5d %10s %10s %12s %s\n",
				j, sym->st_value, sym->st_size,
				sym_type(ELF32_ST_TYPE(sym->st_info)),
				sym_bind(ELF32_ST_BIND(sym->st_info)),
				sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
				name);
		}
	}
	printf("\n");
}

static void print_absolute_relocs(void)
{
	int i, printed = 0;

	for (i = 0; i < ehdr.e_shnum; i++) {
		struct section *sec = &secs[i];
		struct section *sec_applies, *sec_symtab;
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		int j;
		if (sec->shdr.sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = sec->link;
		sec_applies = &secs[sec->shdr.sh_info];
		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab  = sec_symtab->symtab;
		sym_strtab = sec_symtab->link->strtab;
		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			const char *name;
			rel = &sec->reltab[j];
			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
			name = sym_name(sym_strtab, sym);
			if (sym->st_shndx != SHN_ABS) {
				continue;
			}

			/* Absolute symbols are not relocated if bzImage is
			 * loaded at a non-compiled address. Display a warning
			 * to user at compile time about the absolute
			 * relocations present.
			 *
			 * User need to audit the code to make sure
			 * some symbols which should have been section
			 * relative have not become absolute because of some
			 * linker optimization or wrong programming usage.
			 *
			 * Before warning check if this absolute symbol
			 * relocation is harmless.
			 */
			if (is_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;
		struct section *sec_applies, *sec_symtab;
		int j;
		struct section *sec = &secs[i];

		if (sec->shdr.sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = sec->link;
		sec_applies = &secs[sec->shdr.sh_info];
		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = sec_symtab->symtab;
		sym_strtab = sec_symtab->link->strtab;
		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			unsigned r_type;
			rel = &sec->reltab[j];
			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
			r_type = ELF32_R_TYPE(rel->r_info);
			/* Don't visit relocations to absolute symbols */
			if (sym->st_shndx == SHN_ABS) {
				continue;
			}
			if (r_type == R_386_NONE || r_type == R_386_PC32) {
				/*
				 * NONE can be ignored and and 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
ca820181	13	#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
968de4f0	14	static Elf32_Ehdr ehdr;
968de4f0 EB	15	static unsigned long reloc_count, reloc_idx;
	16	static unsigned long *relocs;
	17
908ec7af PA	18	struct section {
	19	Elf32_Shdr shdr;
	20	struct section *link;
	21	Elf32_Sym *symtab;
	22	Elf32_Rel *reltab;
	23	char *strtab;
	24	};
	25	static struct section *secs;
	26
6a044b3a VG	27	/*
	28	* Following symbols have been audited. There values are constant and do
	29	* not change if bzImage is loaded at a different physical address than
	30	* the address for which it has been compiled. Don't warn user about
	31	* absolute relocations present w.r.t these symbols.
	32	*/
	33	static const char* safe_abs_relocs[] = {
600b2fc2 JF	34	"xen_irq_disable_direct_reloc",
600b2fc2 JF	35	"xen_save_fl_direct_reloc",
6a044b3a VG	36	};
	37
	38	static int is_safe_abs_reloc(const char* sym_name)
	39	{
4d022ada	40	int i;
6a044b3a	41
908ec7af	42	for (i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
6a044b3a VG	43	if (!strcmp(sym_name, safe_abs_relocs[i]))
	44	/* Match found */
	45	return 1;
	46	}
4707c471 RM	47	if (strncmp(sym_name, "VDSO", 4) == 0)
4707c471 RM	48	return 1;
2a3d4f1f AV	49	if (strncmp(sym_name, "__crc_", 6) == 0)
2a3d4f1f AV	50	return 1;
6a044b3a VG	51	return 0;
	52	}
	53
968de4f0 EB	54	static void die(char *fmt, ...)
	55	{
	56	va_list ap;
	57	va_start(ap, fmt);
	58	vfprintf(stderr, fmt, ap);
	59	va_end(ap);
	60	exit(1);
	61	}
	62
	63	static const char *sym_type(unsigned type)
	64	{
	65	static const char *type_name[] = {
	66	#define SYM_TYPE(X) [X] = #X
	67	SYM_TYPE(STT_NOTYPE),
	68	SYM_TYPE(STT_OBJECT),
	69	SYM_TYPE(STT_FUNC),
	70	SYM_TYPE(STT_SECTION),
	71	SYM_TYPE(STT_FILE),
	72	SYM_TYPE(STT_COMMON),
	73	SYM_TYPE(STT_TLS),
	74	#undef SYM_TYPE
	75	};
	76	const char *name = "unknown sym type name";
ca820181	77	if (type < ARRAY_SIZE(type_name)) {
968de4f0 EB	78	name = type_name[type];
	79	}
	80	return name;
	81	}
	82
	83	static const char *sym_bind(unsigned bind)
	84	{
	85	static const char *bind_name[] = {
	86	#define SYM_BIND(X) [X] = #X
	87	SYM_BIND(STB_LOCAL),
	88	SYM_BIND(STB_GLOBAL),
	89	SYM_BIND(STB_WEAK),
	90	#undef SYM_BIND
	91	};
	92	const char *name = "unknown sym bind name";
ca820181	93	if (bind < ARRAY_SIZE(bind_name)) {
968de4f0 EB	94	name = bind_name[bind];
	95	}
	96	return name;
	97	}
	98
	99	static const char *sym_visibility(unsigned visibility)
	100	{
	101	static const char *visibility_name[] = {
	102	#define SYM_VISIBILITY(X) [X] = #X
	103	SYM_VISIBILITY(STV_DEFAULT),
	104	SYM_VISIBILITY(STV_INTERNAL),
	105	SYM_VISIBILITY(STV_HIDDEN),
	106	SYM_VISIBILITY(STV_PROTECTED),
	107	#undef SYM_VISIBILITY
	108	};
	109	const char *name = "unknown sym visibility name";
ca820181	110	if (visibility < ARRAY_SIZE(visibility_name)) {
968de4f0 EB	111	name = visibility_name[visibility];
	112	}
	113	return name;
	114	}
	115
	116	static const char *rel_type(unsigned type)
	117	{
	118	static const char *type_name[] = {
	119	#define REL_TYPE(X) [X] = #X
	120	REL_TYPE(R_386_NONE),
	121	REL_TYPE(R_386_32),
	122	REL_TYPE(R_386_PC32),
	123	REL_TYPE(R_386_GOT32),
	124	REL_TYPE(R_386_PLT32),
	125	REL_TYPE(R_386_COPY),
	126	REL_TYPE(R_386_GLOB_DAT),
	127	REL_TYPE(R_386_JMP_SLOT),
	128	REL_TYPE(R_386_RELATIVE),
	129	REL_TYPE(R_386_GOTOFF),
	130	REL_TYPE(R_386_GOTPC),
	131	#undef REL_TYPE
	132	};
	133	const char *name = "unknown type rel type name";
ca820181	134	if (type < ARRAY_SIZE(type_name)) {
968de4f0 EB	135	name = type_name[type];
	136	}
	137	return name;
	138	}
	139
	140	static const char *sec_name(unsigned shndx)
	141	{
	142	const char *sec_strtab;
	143	const char *name;
908ec7af	144	sec_strtab = secs[ehdr.e_shstrndx].strtab;
968de4f0 EB	145	name = "<noname>";
968de4f0 EB	146	if (shndx < ehdr.e_shnum) {
908ec7af	147	name = sec_strtab + secs[shndx].shdr.sh_name;
968de4f0 EB	148	}
	149	else if (shndx == SHN_ABS) {
	150	name = "ABSOLUTE";
	151	}
	152	else if (shndx == SHN_COMMON) {
	153	name = "COMMON";
	154	}
	155	return name;
	156	}
	157
	158	static const char sym_name(const char sym_strtab, Elf32_Sym *sym)
	159	{
	160	const char *name;
	161	name = "<noname>";
	162	if (sym->st_name) {
	163	name = sym_strtab + sym->st_name;
	164	}
	165	else {
908ec7af	166	name = sec_name(secs[sym->st_shndx].shdr.sh_name);
968de4f0 EB	167	}
	168	return name;
	169	}
	170
	171
	172
	173	#if BYTE_ORDER == LITTLE_ENDIAN
	174	#define le16_to_cpu(val) (val)
	175	#define le32_to_cpu(val) (val)
	176	#endif
	177	#if BYTE_ORDER == BIG_ENDIAN
	178	#define le16_to_cpu(val) bswap_16(val)
	179	#define le32_to_cpu(val) bswap_32(val)
	180	#endif
	181
	182	static uint16_t elf16_to_cpu(uint16_t val)
	183	{
	184	return le16_to_cpu(val);
	185	}
	186
	187	static uint32_t elf32_to_cpu(uint32_t val)
	188	{
	189	return le32_to_cpu(val);
	190	}
	191
	192	static void read_ehdr(FILE *fp)
	193	{
	194	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
	195	die("Cannot read ELF header: %s\n",
	196	strerror(errno));
	197	}
8bd1796d	198	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
968de4f0 EB	199	die("No ELF magic\n");
	200	}
	201	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
	202	die("Not a 32 bit executable\n");
	203	}
	204	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
	205	die("Not a LSB ELF executable\n");
	206	}
	207	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
	208	die("Unknown ELF version\n");
	209	}
	210	/* Convert the fields to native endian */
	211	ehdr.e_type = elf16_to_cpu(ehdr.e_type);
	212	ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
	213	ehdr.e_version = elf32_to_cpu(ehdr.e_version);
	214	ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
	215	ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
	216	ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
	217	ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
	218	ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
	219	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
	220	ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
	221	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
	222	ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
	223	ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
	224
	225	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
	226	die("Unsupported ELF header type\n");
	227	}
	228	if (ehdr.e_machine != EM_386) {
	229	die("Not for x86\n");
	230	}
	231	if (ehdr.e_version != EV_CURRENT) {
	232	die("Unknown ELF version\n");
	233	}
	234	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
	235	die("Bad Elf header size\n");
	236	}
	237	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
	238	die("Bad program header entry\n");
	239	}
	240	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
	241	die("Bad section header entry\n");
	242	}
	243	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
	244	die("String table index out of bounds\n");
	245	}
	246	}
	247
	248	static void read_shdrs(FILE *fp)
	249	{
	250	int i;
908ec7af PA	251	Elf32_Shdr shdr;
	252
	253	secs = calloc(ehdr.e_shnum, sizeof(struct section));
	254	if (!secs) {
	255	die("Unable to allocate %d section headers\n",
	256	ehdr.e_shnum);
968de4f0 EB	257	}
	258	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
	259	die("Seek to %d failed: %s\n",
	260	ehdr.e_shoff, strerror(errno));
	261	}
908ec7af PA	262	for (i = 0; i < ehdr.e_shnum; i++) {
	263	struct section *sec = &secs[i];
	264	if (fread(&shdr, sizeof shdr, 1, fp) != 1)
	265	die("Cannot read ELF section headers %d/%d: %s\n",
	266	i, ehdr.e_shnum, strerror(errno));
	267	sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name);
	268	sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type);
	269	sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags);
	270	sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr);
	271	sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset);
	272	sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size);
	273	sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link);
	274	sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info);
	275	sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
	276	sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize);
	277	if (sec->shdr.sh_link < ehdr.e_shnum)
	278	sec->link = &secs[sec->shdr.sh_link];
968de4f0 EB	279	}
	280
	281	}
	282
	283	static void read_strtabs(FILE *fp)
	284	{
	285	int i;
908ec7af PA	286	for (i = 0; i < ehdr.e_shnum; i++) {
	287	struct section *sec = &secs[i];
	288	if (sec->shdr.sh_type != SHT_STRTAB) {
968de4f0 EB	289	continue;
968de4f0 EB	290	}
908ec7af PA	291	sec->strtab = malloc(sec->shdr.sh_size);
908ec7af PA	292	if (!sec->strtab) {
968de4f0	293	die("malloc of %d bytes for strtab failed\n",
908ec7af	294	sec->shdr.sh_size);
968de4f0	295	}
908ec7af	296	if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
968de4f0	297	die("Seek to %d failed: %s\n",
908ec7af	298	sec->shdr.sh_offset, strerror(errno));
968de4f0	299	}
908ec7af PA	300	if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
908ec7af PA	301	!= sec->shdr.sh_size) {
968de4f0 EB	302	die("Cannot read symbol table: %s\n",
	303	strerror(errno));
	304	}
	305	}
	306	}
	307
	308	static void read_symtabs(FILE *fp)
	309	{
	310	int i,j;
908ec7af PA	311	for (i = 0; i < ehdr.e_shnum; i++) {
	312	struct section *sec = &secs[i];
	313	if (sec->shdr.sh_type != SHT_SYMTAB) {
968de4f0 EB	314	continue;
968de4f0 EB	315	}
908ec7af PA	316	sec->symtab = malloc(sec->shdr.sh_size);
908ec7af PA	317	if (!sec->symtab) {
968de4f0	318	die("malloc of %d bytes for symtab failed\n",
908ec7af	319	sec->shdr.sh_size);
968de4f0	320	}
908ec7af	321	if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
968de4f0	322	die("Seek to %d failed: %s\n",
908ec7af	323	sec->shdr.sh_offset, strerror(errno));
968de4f0	324	}
908ec7af PA	325	if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
908ec7af PA	326	!= sec->shdr.sh_size) {
968de4f0 EB	327	die("Cannot read symbol table: %s\n",
	328	strerror(errno));
	329	}
908ec7af PA	330	for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
	331	Elf32_Sym *sym = &sec->symtab[j];
	332	sym->st_name = elf32_to_cpu(sym->st_name);
	333	sym->st_value = elf32_to_cpu(sym->st_value);
	334	sym->st_size = elf32_to_cpu(sym->st_size);
	335	sym->st_shndx = elf16_to_cpu(sym->st_shndx);
968de4f0 EB	336	}
	337	}
	338	}
	339
	340
	341	static void read_relocs(FILE *fp)
	342	{
	343	int i,j;
908ec7af PA	344	for (i = 0; i < ehdr.e_shnum; i++) {
	345	struct section *sec = &secs[i];
	346	if (sec->shdr.sh_type != SHT_REL) {
968de4f0 EB	347	continue;
968de4f0 EB	348	}
908ec7af PA	349	sec->reltab = malloc(sec->shdr.sh_size);
908ec7af PA	350	if (!sec->reltab) {
968de4f0	351	die("malloc of %d bytes for relocs failed\n",
908ec7af	352	sec->shdr.sh_size);
968de4f0	353	}
908ec7af	354	if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
968de4f0	355	die("Seek to %d failed: %s\n",
908ec7af	356	sec->shdr.sh_offset, strerror(errno));
968de4f0	357	}
908ec7af PA	358	if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
908ec7af PA	359	!= sec->shdr.sh_size) {
968de4f0 EB	360	die("Cannot read symbol table: %s\n",
	361	strerror(errno));
	362	}
908ec7af PA	363	for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
	364	Elf32_Rel *rel = &sec->reltab[j];
	365	rel->r_offset = elf32_to_cpu(rel->r_offset);
	366	rel->r_info = elf32_to_cpu(rel->r_info);
968de4f0 EB	367	}
	368	}
	369	}
	370
	371
	372	static void print_absolute_symbols(void)
	373	{
	374	int i;
	375	printf("Absolute symbols\n");
	376	printf(" Num: Value Size Type Bind Visibility Name\n");
908ec7af PA	377	for (i = 0; i < ehdr.e_shnum; i++) {
908ec7af PA	378	struct section *sec = &secs[i];
968de4f0 EB	379	char *sym_strtab;
	380	Elf32_Sym *sh_symtab;
	381	int j;
908ec7af PA	382
908ec7af PA	383	if (sec->shdr.sh_type != SHT_SYMTAB) {
968de4f0 EB	384	continue;
968de4f0 EB	385	}
908ec7af PA	386	sh_symtab = sec->symtab;
	387	sym_strtab = sec->link->strtab;
	388	for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
968de4f0 EB	389	Elf32_Sym *sym;
968de4f0 EB	390	const char *name;
908ec7af	391	sym = &sec->symtab[j];
968de4f0 EB	392	name = sym_name(sym_strtab, sym);
	393	if (sym->st_shndx != SHN_ABS) {
	394	continue;
	395	}
	396	printf("%5d %08x %5d %10s %10s %12s %s\n",
	397	j, sym->st_value, sym->st_size,
	398	sym_type(ELF32_ST_TYPE(sym->st_info)),
	399	sym_bind(ELF32_ST_BIND(sym->st_info)),
	400	sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
	401	name);
	402	}
	403	}
	404	printf("\n");
	405	}
	406
	407	static void print_absolute_relocs(void)
	408	{
6a044b3a VG	409	int i, printed = 0;
6a044b3a VG	410
908ec7af PA	411	for (i = 0; i < ehdr.e_shnum; i++) {
	412	struct section *sec = &secs[i];
	413	struct section sec_applies, sec_symtab;
968de4f0 EB	414	char *sym_strtab;
968de4f0 EB	415	Elf32_Sym *sh_symtab;
968de4f0	416	int j;
908ec7af	417	if (sec->shdr.sh_type != SHT_REL) {
968de4f0 EB	418	continue;
968de4f0 EB	419	}
908ec7af PA	420	sec_symtab = sec->link;
	421	sec_applies = &secs[sec->shdr.sh_info];
	422	if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
968de4f0 EB	423	continue;
968de4f0 EB	424	}
908ec7af PA	425	sh_symtab = sec_symtab->symtab;
	426	sym_strtab = sec_symtab->link->strtab;
	427	for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
968de4f0 EB	428	Elf32_Rel *rel;
	429	Elf32_Sym *sym;
	430	const char *name;
908ec7af	431	rel = &sec->reltab[j];
968de4f0 EB	432	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
	433	name = sym_name(sym_strtab, sym);
	434	if (sym->st_shndx != SHN_ABS) {
	435	continue;
	436	}
6a044b3a VG	437
	438	/* Absolute symbols are not relocated if bzImage is
	439	* loaded at a non-compiled address. Display a warning
	440	* to user at compile time about the absolute
	441	* relocations present.
	442	*
	443	* User need to audit the code to make sure
	444	* some symbols which should have been section
	445	* relative have not become absolute because of some
	446	* linker optimization or wrong programming usage.
	447	*
	448	* Before warning check if this absolute symbol
	449	* relocation is harmless.
	450	*/
	451	if (is_safe_abs_reloc(name))
	452	continue;
	453
	454	if (!printed) {
	455	printf("WARNING: Absolute relocations"
	456	" present\n");
	457	printf("Offset Info Type Sym.Value "
	458	"Sym.Name\n");
	459	printed = 1;
	460	}
	461
968de4f0 EB	462	printf("%08x %08x %10s %08x %s\n",
	463	rel->r_offset,
	464	rel->r_info,
	465	rel_type(ELF32_R_TYPE(rel->r_info)),
	466	sym->st_value,
	467	name);
	468	}
	469	}
6a044b3a VG	470
	471	if (printed)
	472	printf("\n");
968de4f0 EB	473	}
	474
	475	static void walk_relocs(void (visit)(Elf32_Rel rel, Elf32_Sym *sym))
	476	{
	477	int i;
	478	/* Walk through the relocations */
908ec7af	479	for (i = 0; i < ehdr.e_shnum; i++) {
968de4f0 EB	480	char *sym_strtab;
968de4f0 EB	481	Elf32_Sym *sh_symtab;
908ec7af	482	struct section sec_applies, sec_symtab;
968de4f0	483	int j;
908ec7af PA	484	struct section *sec = &secs[i];
	485
	486	if (sec->shdr.sh_type != SHT_REL) {
968de4f0 EB	487	continue;
968de4f0 EB	488	}
908ec7af PA	489	sec_symtab = sec->link;
	490	sec_applies = &secs[sec->shdr.sh_info];
	491	if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
968de4f0 EB	492	continue;
968de4f0 EB	493	}
908ec7af	494	sh_symtab = sec_symtab->symtab;
cc65f1ec	495	sym_strtab = sec_symtab->link->strtab;
908ec7af	496	for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
968de4f0 EB	497	Elf32_Rel *rel;
	498	Elf32_Sym *sym;
	499	unsigned r_type;
908ec7af	500	rel = &sec->reltab[j];
968de4f0 EB	501	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
	502	r_type = ELF32_R_TYPE(rel->r_info);
	503	/* Don't visit relocations to absolute symbols */
	504	if (sym->st_shndx == SHN_ABS) {
	505	continue;
	506	}
46176b4f TH	507	if (r_type == R_386_NONE \|\| r_type == R_386_PC32) {
	508	/*
	509	* NONE can be ignored and and PC relative
	510	* relocations don't need to be adjusted.
	511	*/
968de4f0 EB	512	}
	513	else if (r_type == R_386_32) {
	514	/* Visit relocations that need to be adjusted */
	515	visit(rel, sym);
	516	}
	517	else {
	518	die("Unsupported relocation type: %d\n", r_type);
	519	}
	520	}
	521	}
	522	}
	523
	524	static void count_reloc(Elf32_Rel rel, Elf32_Sym sym)
	525	{
	526	reloc_count += 1;
	527	}
	528
	529	static void collect_reloc(Elf32_Rel rel, Elf32_Sym sym)
	530	{
	531	/* Remember the address that needs to be adjusted. */
	532	relocs[reloc_idx++] = rel->r_offset;
	533	}
	534
	535	static int cmp_relocs(const void va, const void vb)
	536	{
	537	const unsigned long a, b;
	538	a = va; b = vb;
	539	return (a == b)? 0 : (a > b)? 1 : -1;
	540	}
	541
	542	static void emit_relocs(int as_text)
	543	{
	544	int i;
	545	/* Count how many relocations I have and allocate space for them. */
	546	reloc_count = 0;
	547	walk_relocs(count_reloc);
	548	relocs = malloc(reloc_count * sizeof(relocs[0]));
	549	if (!relocs) {
	550	die("malloc of %d entries for relocs failed\n",
	551	reloc_count);
	552	}
	553	/* Collect up the relocations */
	554	reloc_idx = 0;
	555	walk_relocs(collect_reloc);
	556
	557	/* Order the relocations for more efficient processing */
	558	qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
	559
	560	/* Print the relocations */
	561	if (as_text) {
	562	/* Print the relocations in a form suitable that
	563	* gas will like.
	564	*/
	565	printf(".section \".data.reloc\",\"a\"\n");
	566	printf(".balign 4\n");
908ec7af	567	for (i = 0; i < reloc_count; i++) {
968de4f0 EB	568	printf("\t .long 0x%08lx\n", relocs[i]);
	569	}
	570	printf("\n");
	571	}
	572	else {
	573	unsigned char buf[4];
	574	buf[0] = buf[1] = buf[2] = buf[3] = 0;
	575	/* Print a stop */
	576	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
	577	/* Now print each relocation */
908ec7af	578	for (i = 0; i < reloc_count; i++) {
968de4f0 EB	579	buf[0] = (relocs[i] >> 0) & 0xff;
	580	buf[1] = (relocs[i] >> 8) & 0xff;
	581	buf[2] = (relocs[i] >> 16) & 0xff;
	582	buf[3] = (relocs[i] >> 24) & 0xff;
	583	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
	584	}
	585	}
	586	}
	587
	588	static void usage(void)
	589	{
6a044b3a	590	die("relocs [--abs-syms \|--abs-relocs \| --text] vmlinux\n");
968de4f0 EB	591	}
	592
	593	int main(int argc, char **argv)
	594	{
6a044b3a	595	int show_absolute_syms, show_absolute_relocs;
968de4f0 EB	596	int as_text;
	597	const char *fname;
	598	FILE *fp;
	599	int i;
	600
6a044b3a VG	601	show_absolute_syms = 0;
6a044b3a VG	602	show_absolute_relocs = 0;
968de4f0 EB	603	as_text = 0;
968de4f0 EB	604	fname = NULL;
908ec7af	605	for (i = 1; i < argc; i++) {
968de4f0 EB	606	char *arg = argv[i];
968de4f0 EB	607	if (*arg == '-') {
6a044b3a VG	608	if (strcmp(argv[1], "--abs-syms") == 0) {
	609	show_absolute_syms = 1;
	610	continue;
	611	}
	612
	613	if (strcmp(argv[1], "--abs-relocs") == 0) {
	614	show_absolute_relocs = 1;
968de4f0 EB	615	continue;
	616	}
	617	else if (strcmp(argv[1], "--text") == 0) {
	618	as_text = 1;
	619	continue;
	620	}
	621	}
	622	else if (!fname) {
	623	fname = arg;
	624	continue;
	625	}
	626	usage();
	627	}
	628	if (!fname) {
	629	usage();
	630	}
	631	fp = fopen(fname, "r");
	632	if (!fp) {
	633	die("Cannot open %s: %s\n",
	634	fname, strerror(errno));
	635	}
	636	read_ehdr(fp);
	637	read_shdrs(fp);
	638	read_strtabs(fp);
	639	read_symtabs(fp);
	640	read_relocs(fp);
6a044b3a	641	if (show_absolute_syms) {
968de4f0	642	print_absolute_symbols();
6a044b3a VG	643	return 0;
	644	}
	645	if (show_absolute_relocs) {
968de4f0 EB	646	print_absolute_relocs();
	647	return 0;
	648	}
	649	emit_relocs(as_text);
	650	return 0;
	651	}