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v4.10.11
 
   1/* This is included from relocs_32/64.c */
   2
   3#define ElfW(type)		_ElfW(ELF_BITS, type)
   4#define _ElfW(bits, type)	__ElfW(bits, type)
   5#define __ElfW(bits, type)	Elf##bits##_##type
   6
   7#define Elf_Addr		ElfW(Addr)
   8#define Elf_Ehdr		ElfW(Ehdr)
   9#define Elf_Phdr		ElfW(Phdr)
  10#define Elf_Shdr		ElfW(Shdr)
  11#define Elf_Sym			ElfW(Sym)
  12
  13static Elf_Ehdr ehdr;
 
 
  14
  15struct relocs {
  16	uint32_t	*offset;
  17	unsigned long	count;
  18	unsigned long	size;
  19};
  20
  21static struct relocs relocs16;
  22static struct relocs relocs32;
  23#if ELF_BITS == 64
  24static struct relocs relocs32neg;
  25static struct relocs relocs64;
  26#endif
  27
  28struct section {
  29	Elf_Shdr       shdr;
  30	struct section *link;
  31	Elf_Sym        *symtab;
  32	Elf_Rel        *reltab;
  33	char           *strtab;
  34};
  35static struct section *secs;
  36
  37static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  38/*
  39 * Following symbols have been audited. There values are constant and do
  40 * not change if bzImage is loaded at a different physical address than
  41 * the address for which it has been compiled. Don't warn user about
  42 * absolute relocations present w.r.t these symbols.
  43 */
  44	[S_ABS] =
  45	"^(xen_irq_disable_direct_reloc$|"
  46	"xen_save_fl_direct_reloc$|"
  47	"VDSO|"
  48	"__crc_)",
  49
  50/*
  51 * These symbols are known to be relative, even if the linker marks them
  52 * as absolute (typically defined outside any section in the linker script.)
  53 */
  54	[S_REL] =
  55	"^(__init_(begin|end)|"
  56	"__x86_cpu_dev_(start|end)|"
  57	"(__parainstructions|__alt_instructions)(|_end)|"
  58	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
  59	"__(start|end)_pci_.*|"
  60	"__(start|end)_builtin_fw|"
  61	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  62	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  63	"__(start|stop)___param|"
  64	"__(start|stop)___modver|"
  65	"__(start|stop)___bug_table|"
  66	"__tracedata_(start|end)|"
  67	"__(start|stop)_notes|"
  68	"__end_rodata|"
 
  69	"__initramfs_start|"
  70	"(jiffies|jiffies_64)|"
  71#if ELF_BITS == 64
  72	"__per_cpu_load|"
  73	"init_per_cpu__.*|"
  74	"__end_rodata_hpage_align|"
  75#endif
  76	"__vvar_page|"
  77	"_end)$"
  78};
  79
  80
  81static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  82/*
  83 * These symbols are known to be relative, even if the linker marks them
  84 * as absolute (typically defined outside any section in the linker script.)
  85 */
  86	[S_REL] =
  87	"^pa_",
  88
  89/*
  90 * These are 16-bit segment symbols when compiling 16-bit code.
  91 */
  92	[S_SEG] =
  93	"^real_mode_seg$",
  94
  95/*
  96 * These are offsets belonging to segments, as opposed to linear addresses,
  97 * when compiling 16-bit code.
  98 */
  99	[S_LIN] =
 100	"^pa_",
 101};
 102
 103static const char * const *sym_regex;
 104
 105static regex_t sym_regex_c[S_NSYMTYPES];
 106static int is_reloc(enum symtype type, const char *sym_name)
 107{
 108	return sym_regex[type] &&
 109		!regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
 110}
 111
 112static void regex_init(int use_real_mode)
 113{
 114        char errbuf[128];
 115        int err;
 116	int i;
 117
 118	if (use_real_mode)
 119		sym_regex = sym_regex_realmode;
 120	else
 121		sym_regex = sym_regex_kernel;
 122
 123	for (i = 0; i < S_NSYMTYPES; i++) {
 124		if (!sym_regex[i])
 125			continue;
 126
 127		err = regcomp(&sym_regex_c[i], sym_regex[i],
 128			      REG_EXTENDED|REG_NOSUB);
 129
 130		if (err) {
 131			regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 132			die("%s", errbuf);
 133		}
 134        }
 135}
 136
 137static const char *sym_type(unsigned type)
 138{
 139	static const char *type_name[] = {
 140#define SYM_TYPE(X) [X] = #X
 141		SYM_TYPE(STT_NOTYPE),
 142		SYM_TYPE(STT_OBJECT),
 143		SYM_TYPE(STT_FUNC),
 144		SYM_TYPE(STT_SECTION),
 145		SYM_TYPE(STT_FILE),
 146		SYM_TYPE(STT_COMMON),
 147		SYM_TYPE(STT_TLS),
 148#undef SYM_TYPE
 149	};
 150	const char *name = "unknown sym type name";
 151	if (type < ARRAY_SIZE(type_name)) {
 152		name = type_name[type];
 153	}
 154	return name;
 155}
 156
 157static const char *sym_bind(unsigned bind)
 158{
 159	static const char *bind_name[] = {
 160#define SYM_BIND(X) [X] = #X
 161		SYM_BIND(STB_LOCAL),
 162		SYM_BIND(STB_GLOBAL),
 163		SYM_BIND(STB_WEAK),
 164#undef SYM_BIND
 165	};
 166	const char *name = "unknown sym bind name";
 167	if (bind < ARRAY_SIZE(bind_name)) {
 168		name = bind_name[bind];
 169	}
 170	return name;
 171}
 172
 173static const char *sym_visibility(unsigned visibility)
 174{
 175	static const char *visibility_name[] = {
 176#define SYM_VISIBILITY(X) [X] = #X
 177		SYM_VISIBILITY(STV_DEFAULT),
 178		SYM_VISIBILITY(STV_INTERNAL),
 179		SYM_VISIBILITY(STV_HIDDEN),
 180		SYM_VISIBILITY(STV_PROTECTED),
 181#undef SYM_VISIBILITY
 182	};
 183	const char *name = "unknown sym visibility name";
 184	if (visibility < ARRAY_SIZE(visibility_name)) {
 185		name = visibility_name[visibility];
 186	}
 187	return name;
 188}
 189
 190static const char *rel_type(unsigned type)
 191{
 192	static const char *type_name[] = {
 193#define REL_TYPE(X) [X] = #X
 194#if ELF_BITS == 64
 195		REL_TYPE(R_X86_64_NONE),
 196		REL_TYPE(R_X86_64_64),
 
 197		REL_TYPE(R_X86_64_PC32),
 198		REL_TYPE(R_X86_64_GOT32),
 199		REL_TYPE(R_X86_64_PLT32),
 200		REL_TYPE(R_X86_64_COPY),
 201		REL_TYPE(R_X86_64_GLOB_DAT),
 202		REL_TYPE(R_X86_64_JUMP_SLOT),
 203		REL_TYPE(R_X86_64_RELATIVE),
 204		REL_TYPE(R_X86_64_GOTPCREL),
 205		REL_TYPE(R_X86_64_32),
 206		REL_TYPE(R_X86_64_32S),
 207		REL_TYPE(R_X86_64_16),
 208		REL_TYPE(R_X86_64_PC16),
 209		REL_TYPE(R_X86_64_8),
 210		REL_TYPE(R_X86_64_PC8),
 211#else
 212		REL_TYPE(R_386_NONE),
 213		REL_TYPE(R_386_32),
 214		REL_TYPE(R_386_PC32),
 215		REL_TYPE(R_386_GOT32),
 216		REL_TYPE(R_386_PLT32),
 217		REL_TYPE(R_386_COPY),
 218		REL_TYPE(R_386_GLOB_DAT),
 219		REL_TYPE(R_386_JMP_SLOT),
 220		REL_TYPE(R_386_RELATIVE),
 221		REL_TYPE(R_386_GOTOFF),
 222		REL_TYPE(R_386_GOTPC),
 223		REL_TYPE(R_386_8),
 224		REL_TYPE(R_386_PC8),
 225		REL_TYPE(R_386_16),
 226		REL_TYPE(R_386_PC16),
 227#endif
 228#undef REL_TYPE
 229	};
 230	const char *name = "unknown type rel type name";
 231	if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 232		name = type_name[type];
 233	}
 234	return name;
 235}
 236
 237static const char *sec_name(unsigned shndx)
 238{
 239	const char *sec_strtab;
 240	const char *name;
 241	sec_strtab = secs[ehdr.e_shstrndx].strtab;
 242	name = "<noname>";
 243	if (shndx < ehdr.e_shnum) {
 244		name = sec_strtab + secs[shndx].shdr.sh_name;
 245	}
 246	else if (shndx == SHN_ABS) {
 247		name = "ABSOLUTE";
 248	}
 249	else if (shndx == SHN_COMMON) {
 250		name = "COMMON";
 251	}
 252	return name;
 253}
 254
 255static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
 256{
 257	const char *name;
 258	name = "<noname>";
 259	if (sym->st_name) {
 260		name = sym_strtab + sym->st_name;
 261	}
 262	else {
 263		name = sec_name(sym->st_shndx);
 264	}
 265	return name;
 266}
 267
 268static Elf_Sym *sym_lookup(const char *symname)
 269{
 270	int i;
 271	for (i = 0; i < ehdr.e_shnum; i++) {
 272		struct section *sec = &secs[i];
 273		long nsyms;
 274		char *strtab;
 275		Elf_Sym *symtab;
 276		Elf_Sym *sym;
 277
 278		if (sec->shdr.sh_type != SHT_SYMTAB)
 279			continue;
 280
 281		nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
 282		symtab = sec->symtab;
 283		strtab = sec->link->strtab;
 284
 285		for (sym = symtab; --nsyms >= 0; sym++) {
 286			if (!sym->st_name)
 287				continue;
 288			if (strcmp(symname, strtab + sym->st_name) == 0)
 289				return sym;
 290		}
 291	}
 292	return 0;
 293}
 294
 295#if BYTE_ORDER == LITTLE_ENDIAN
 296#define le16_to_cpu(val) (val)
 297#define le32_to_cpu(val) (val)
 298#define le64_to_cpu(val) (val)
 299#endif
 300#if BYTE_ORDER == BIG_ENDIAN
 301#define le16_to_cpu(val) bswap_16(val)
 302#define le32_to_cpu(val) bswap_32(val)
 303#define le64_to_cpu(val) bswap_64(val)
 304#endif
 305
 306static uint16_t elf16_to_cpu(uint16_t val)
 307{
 308	return le16_to_cpu(val);
 309}
 310
 311static uint32_t elf32_to_cpu(uint32_t val)
 312{
 313	return le32_to_cpu(val);
 314}
 315
 316#define elf_half_to_cpu(x)	elf16_to_cpu(x)
 317#define elf_word_to_cpu(x)	elf32_to_cpu(x)
 318
 319#if ELF_BITS == 64
 320static uint64_t elf64_to_cpu(uint64_t val)
 321{
 322        return le64_to_cpu(val);
 323}
 324#define elf_addr_to_cpu(x)	elf64_to_cpu(x)
 325#define elf_off_to_cpu(x)	elf64_to_cpu(x)
 326#define elf_xword_to_cpu(x)	elf64_to_cpu(x)
 327#else
 328#define elf_addr_to_cpu(x)	elf32_to_cpu(x)
 329#define elf_off_to_cpu(x)	elf32_to_cpu(x)
 330#define elf_xword_to_cpu(x)	elf32_to_cpu(x)
 331#endif
 332
 333static void read_ehdr(FILE *fp)
 334{
 335	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 336		die("Cannot read ELF header: %s\n",
 337			strerror(errno));
 338	}
 339	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 340		die("No ELF magic\n");
 341	}
 342	if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
 343		die("Not a %d bit executable\n", ELF_BITS);
 344	}
 345	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 346		die("Not a LSB ELF executable\n");
 347	}
 348	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 349		die("Unknown ELF version\n");
 350	}
 351	/* Convert the fields to native endian */
 352	ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
 353	ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
 354	ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
 355	ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
 356	ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
 357	ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
 358	ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
 359	ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
 360	ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
 361	ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
 362	ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
 363	ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
 364	ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);
 365
 366	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 
 
 
 367		die("Unsupported ELF header type\n");
 368	}
 369	if (ehdr.e_machine != ELF_MACHINE) {
 370		die("Not for %s\n", ELF_MACHINE_NAME);
 371	}
 372	if (ehdr.e_version != EV_CURRENT) {
 373		die("Unknown ELF version\n");
 374	}
 375	if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
 376		die("Bad Elf header size\n");
 377	}
 378	if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
 379		die("Bad program header entry\n");
 380	}
 381	if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
 382		die("Bad section header entry\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 383	}
 384	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 
 385		die("String table index out of bounds\n");
 386	}
 387}
 388
 389static void read_shdrs(FILE *fp)
 390{
 391	int i;
 392	Elf_Shdr shdr;
 393
 394	secs = calloc(ehdr.e_shnum, sizeof(struct section));
 395	if (!secs) {
 396		die("Unable to allocate %d section headers\n",
 397		    ehdr.e_shnum);
 398	}
 399	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 400		die("Seek to %d failed: %s\n",
 401			ehdr.e_shoff, strerror(errno));
 402	}
 403	for (i = 0; i < ehdr.e_shnum; i++) {
 404		struct section *sec = &secs[i];
 405		if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 406			die("Cannot read ELF section headers %d/%d: %s\n",
 407			    i, ehdr.e_shnum, strerror(errno));
 408		sec->shdr.sh_name      = elf_word_to_cpu(shdr.sh_name);
 409		sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
 410		sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
 411		sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
 412		sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
 413		sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
 414		sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
 415		sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
 416		sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
 417		sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
 418		if (sec->shdr.sh_link < ehdr.e_shnum)
 419			sec->link = &secs[sec->shdr.sh_link];
 420	}
 421
 422}
 423
 424static void read_strtabs(FILE *fp)
 425{
 426	int i;
 427	for (i = 0; i < ehdr.e_shnum; i++) {
 428		struct section *sec = &secs[i];
 429		if (sec->shdr.sh_type != SHT_STRTAB) {
 430			continue;
 431		}
 432		sec->strtab = malloc(sec->shdr.sh_size);
 433		if (!sec->strtab) {
 434			die("malloc of %d bytes for strtab failed\n",
 435				sec->shdr.sh_size);
 436		}
 437		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 438			die("Seek to %d failed: %s\n",
 439				sec->shdr.sh_offset, strerror(errno));
 440		}
 441		if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 442		    != sec->shdr.sh_size) {
 443			die("Cannot read symbol table: %s\n",
 444				strerror(errno));
 445		}
 446	}
 447}
 448
 449static void read_symtabs(FILE *fp)
 450{
 451	int i,j;
 452	for (i = 0; i < ehdr.e_shnum; i++) {
 453		struct section *sec = &secs[i];
 454		if (sec->shdr.sh_type != SHT_SYMTAB) {
 455			continue;
 456		}
 457		sec->symtab = malloc(sec->shdr.sh_size);
 458		if (!sec->symtab) {
 459			die("malloc of %d bytes for symtab failed\n",
 460				sec->shdr.sh_size);
 461		}
 462		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 463			die("Seek to %d failed: %s\n",
 464				sec->shdr.sh_offset, strerror(errno));
 465		}
 466		if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 467		    != sec->shdr.sh_size) {
 468			die("Cannot read symbol table: %s\n",
 469				strerror(errno));
 470		}
 471		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
 472			Elf_Sym *sym = &sec->symtab[j];
 473			sym->st_name  = elf_word_to_cpu(sym->st_name);
 474			sym->st_value = elf_addr_to_cpu(sym->st_value);
 475			sym->st_size  = elf_xword_to_cpu(sym->st_size);
 476			sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
 477		}
 478	}
 479}
 480
 481
 482static void read_relocs(FILE *fp)
 483{
 484	int i,j;
 485	for (i = 0; i < ehdr.e_shnum; i++) {
 486		struct section *sec = &secs[i];
 487		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 488			continue;
 489		}
 490		sec->reltab = malloc(sec->shdr.sh_size);
 491		if (!sec->reltab) {
 492			die("malloc of %d bytes for relocs failed\n",
 493				sec->shdr.sh_size);
 494		}
 495		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 496			die("Seek to %d failed: %s\n",
 497				sec->shdr.sh_offset, strerror(errno));
 498		}
 499		if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 500		    != sec->shdr.sh_size) {
 501			die("Cannot read symbol table: %s\n",
 502				strerror(errno));
 503		}
 504		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 505			Elf_Rel *rel = &sec->reltab[j];
 506			rel->r_offset = elf_addr_to_cpu(rel->r_offset);
 507			rel->r_info   = elf_xword_to_cpu(rel->r_info);
 508#if (SHT_REL_TYPE == SHT_RELA)
 509			rel->r_addend = elf_xword_to_cpu(rel->r_addend);
 510#endif
 511		}
 512	}
 513}
 514
 515
 516static void print_absolute_symbols(void)
 517{
 518	int i;
 519	const char *format;
 520
 521	if (ELF_BITS == 64)
 522		format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
 523	else
 524		format = "%5d %08"PRIx32"  %5"PRId32" %10s %10s %12s %s\n";
 525
 526	printf("Absolute symbols\n");
 527	printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 528	for (i = 0; i < ehdr.e_shnum; i++) {
 529		struct section *sec = &secs[i];
 530		char *sym_strtab;
 531		int j;
 532
 533		if (sec->shdr.sh_type != SHT_SYMTAB) {
 534			continue;
 535		}
 536		sym_strtab = sec->link->strtab;
 537		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
 538			Elf_Sym *sym;
 539			const char *name;
 540			sym = &sec->symtab[j];
 541			name = sym_name(sym_strtab, sym);
 542			if (sym->st_shndx != SHN_ABS) {
 543				continue;
 544			}
 545			printf(format,
 546				j, sym->st_value, sym->st_size,
 547				sym_type(ELF_ST_TYPE(sym->st_info)),
 548				sym_bind(ELF_ST_BIND(sym->st_info)),
 549				sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
 550				name);
 551		}
 552	}
 553	printf("\n");
 554}
 555
 556static void print_absolute_relocs(void)
 557{
 558	int i, printed = 0;
 559	const char *format;
 560
 561	if (ELF_BITS == 64)
 562		format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64"  %s\n";
 563	else
 564		format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32"  %s\n";
 565
 566	for (i = 0; i < ehdr.e_shnum; i++) {
 567		struct section *sec = &secs[i];
 568		struct section *sec_applies, *sec_symtab;
 569		char *sym_strtab;
 570		Elf_Sym *sh_symtab;
 571		int j;
 572		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 573			continue;
 574		}
 575		sec_symtab  = sec->link;
 576		sec_applies = &secs[sec->shdr.sh_info];
 577		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 578			continue;
 579		}
 580		sh_symtab  = sec_symtab->symtab;
 581		sym_strtab = sec_symtab->link->strtab;
 582		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 583			Elf_Rel *rel;
 584			Elf_Sym *sym;
 585			const char *name;
 586			rel = &sec->reltab[j];
 587			sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 588			name = sym_name(sym_strtab, sym);
 589			if (sym->st_shndx != SHN_ABS) {
 590				continue;
 591			}
 592
 593			/* Absolute symbols are not relocated if bzImage is
 594			 * loaded at a non-compiled address. Display a warning
 595			 * to user at compile time about the absolute
 596			 * relocations present.
 597			 *
 598			 * User need to audit the code to make sure
 599			 * some symbols which should have been section
 600			 * relative have not become absolute because of some
 601			 * linker optimization or wrong programming usage.
 602			 *
 603			 * Before warning check if this absolute symbol
 604			 * relocation is harmless.
 605			 */
 606			if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 607				continue;
 608
 609			if (!printed) {
 610				printf("WARNING: Absolute relocations"
 611					" present\n");
 612				printf("Offset     Info     Type     Sym.Value "
 613					"Sym.Name\n");
 614				printed = 1;
 615			}
 616
 617			printf(format,
 618				rel->r_offset,
 619				rel->r_info,
 620				rel_type(ELF_R_TYPE(rel->r_info)),
 621				sym->st_value,
 622				name);
 623		}
 624	}
 625
 626	if (printed)
 627		printf("\n");
 628}
 629
 630static void add_reloc(struct relocs *r, uint32_t offset)
 631{
 632	if (r->count == r->size) {
 633		unsigned long newsize = r->size + 50000;
 634		void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
 635
 636		if (!mem)
 637			die("realloc of %ld entries for relocs failed\n",
 638                                newsize);
 639		r->offset = mem;
 640		r->size = newsize;
 641	}
 642	r->offset[r->count++] = offset;
 643}
 644
 645static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 646			Elf_Sym *sym, const char *symname))
 647{
 648	int i;
 649	/* Walk through the relocations */
 650	for (i = 0; i < ehdr.e_shnum; i++) {
 651		char *sym_strtab;
 652		Elf_Sym *sh_symtab;
 653		struct section *sec_applies, *sec_symtab;
 654		int j;
 655		struct section *sec = &secs[i];
 656
 657		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 658			continue;
 659		}
 660		sec_symtab  = sec->link;
 661		sec_applies = &secs[sec->shdr.sh_info];
 662		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 663			continue;
 664		}
 665		sh_symtab = sec_symtab->symtab;
 666		sym_strtab = sec_symtab->link->strtab;
 667		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 668			Elf_Rel *rel = &sec->reltab[j];
 669			Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 670			const char *symname = sym_name(sym_strtab, sym);
 671
 672			process(sec, rel, sym, symname);
 673		}
 674	}
 675}
 676
 677/*
 678 * The .data..percpu section is a special case for x86_64 SMP kernels.
 679 * It is used to initialize the actual per_cpu areas and to provide
 680 * definitions for the per_cpu variables that correspond to their offsets
 681 * within the percpu area. Since the values of all of the symbols need
 682 * to be offsets from the start of the per_cpu area the virtual address
 683 * (sh_addr) of .data..percpu is 0 in SMP kernels.
 684 *
 685 * This means that:
 686 *
 687 *	Relocations that reference symbols in the per_cpu area do not
 688 *	need further relocation (since the value is an offset relative
 689 *	to the start of the per_cpu area that does not change).
 690 *
 691 *	Relocations that apply to the per_cpu area need to have their
 692 *	offset adjusted by by the value of __per_cpu_load to make them
 693 *	point to the correct place in the loaded image (because the
 694 *	virtual address of .data..percpu is 0).
 695 *
 696 * For non SMP kernels .data..percpu is linked as part of the normal
 697 * kernel data and does not require special treatment.
 698 *
 699 */
 700static int per_cpu_shndx	= -1;
 701static Elf_Addr per_cpu_load_addr;
 702
 703static void percpu_init(void)
 704{
 705	int i;
 706	for (i = 0; i < ehdr.e_shnum; i++) {
 707		ElfW(Sym) *sym;
 708		if (strcmp(sec_name(i), ".data..percpu"))
 709			continue;
 710
 711		if (secs[i].shdr.sh_addr != 0)	/* non SMP kernel */
 712			return;
 713
 714		sym = sym_lookup("__per_cpu_load");
 715		if (!sym)
 716			die("can't find __per_cpu_load\n");
 717
 718		per_cpu_shndx = i;
 719		per_cpu_load_addr = sym->st_value;
 720		return;
 721	}
 722}
 723
 724#if ELF_BITS == 64
 725
 726/*
 727 * Check to see if a symbol lies in the .data..percpu section.
 728 *
 729 * The linker incorrectly associates some symbols with the
 730 * .data..percpu section so we also need to check the symbol
 731 * name to make sure that we classify the symbol correctly.
 732 *
 733 * The GNU linker incorrectly associates:
 734 *	__init_begin
 735 *	__per_cpu_load
 736 *
 737 * The "gold" linker incorrectly associates:
 738 *	init_per_cpu__irq_stack_union
 739 *	init_per_cpu__gdt_page
 740 */
 741static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
 742{
 743	return (sym->st_shndx == per_cpu_shndx) &&
 744		strcmp(symname, "__init_begin") &&
 745		strcmp(symname, "__per_cpu_load") &&
 746		strncmp(symname, "init_per_cpu_", 13);
 747}
 748
 749
 750static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 751		      const char *symname)
 752{
 753	unsigned r_type = ELF64_R_TYPE(rel->r_info);
 754	ElfW(Addr) offset = rel->r_offset;
 755	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 756
 757	if (sym->st_shndx == SHN_UNDEF)
 758		return 0;
 759
 760	/*
 761	 * Adjust the offset if this reloc applies to the percpu section.
 762	 */
 763	if (sec->shdr.sh_info == per_cpu_shndx)
 764		offset += per_cpu_load_addr;
 765
 766	switch (r_type) {
 767	case R_X86_64_NONE:
 768		/* NONE can be ignored. */
 769		break;
 770
 771	case R_X86_64_PC32:
 
 772		/*
 773		 * PC relative relocations don't need to be adjusted unless
 774		 * referencing a percpu symbol.
 
 
 775		 */
 776		if (is_percpu_sym(sym, symname))
 777			add_reloc(&relocs32neg, offset);
 
 
 
 
 
 
 
 
 
 778		break;
 779
 780	case R_X86_64_32:
 781	case R_X86_64_32S:
 782	case R_X86_64_64:
 783		/*
 784		 * References to the percpu area don't need to be adjusted.
 785		 */
 786		if (is_percpu_sym(sym, symname))
 787			break;
 788
 789		if (shn_abs) {
 790			/*
 791			 * Whitelisted absolute symbols do not require
 792			 * relocation.
 793			 */
 794			if (is_reloc(S_ABS, symname))
 795				break;
 796
 797			die("Invalid absolute %s relocation: %s\n",
 798			    rel_type(r_type), symname);
 799			break;
 800		}
 801
 802		/*
 803		 * Relocation offsets for 64 bit kernels are output
 804		 * as 32 bits and sign extended back to 64 bits when
 805		 * the relocations are processed.
 806		 * Make sure that the offset will fit.
 807		 */
 808		if ((int32_t)offset != (int64_t)offset)
 809			die("Relocation offset doesn't fit in 32 bits\n");
 810
 811		if (r_type == R_X86_64_64)
 812			add_reloc(&relocs64, offset);
 813		else
 814			add_reloc(&relocs32, offset);
 815		break;
 816
 817	default:
 818		die("Unsupported relocation type: %s (%d)\n",
 819		    rel_type(r_type), r_type);
 820		break;
 821	}
 822
 823	return 0;
 824}
 825
 826#else
 827
 828static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 829		      const char *symname)
 830{
 831	unsigned r_type = ELF32_R_TYPE(rel->r_info);
 832	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 833
 834	switch (r_type) {
 835	case R_386_NONE:
 836	case R_386_PC32:
 837	case R_386_PC16:
 838	case R_386_PC8:
 839		/*
 840		 * NONE can be ignored and PC relative relocations don't
 841		 * need to be adjusted.
 842		 */
 843		break;
 844
 845	case R_386_32:
 846		if (shn_abs) {
 847			/*
 848			 * Whitelisted absolute symbols do not require
 849			 * relocation.
 850			 */
 851			if (is_reloc(S_ABS, symname))
 852				break;
 853
 854			die("Invalid absolute %s relocation: %s\n",
 855			    rel_type(r_type), symname);
 856			break;
 857		}
 858
 859		add_reloc(&relocs32, rel->r_offset);
 860		break;
 861
 862	default:
 863		die("Unsupported relocation type: %s (%d)\n",
 864		    rel_type(r_type), r_type);
 865		break;
 866	}
 867
 868	return 0;
 869}
 870
 871static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 872			 const char *symname)
 873{
 874	unsigned r_type = ELF32_R_TYPE(rel->r_info);
 875	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 876
 877	switch (r_type) {
 878	case R_386_NONE:
 879	case R_386_PC32:
 880	case R_386_PC16:
 881	case R_386_PC8:
 882		/*
 883		 * NONE can be ignored and PC relative relocations don't
 884		 * need to be adjusted.
 885		 */
 886		break;
 887
 888	case R_386_16:
 889		if (shn_abs) {
 890			/*
 891			 * Whitelisted absolute symbols do not require
 892			 * relocation.
 893			 */
 894			if (is_reloc(S_ABS, symname))
 895				break;
 896
 897			if (is_reloc(S_SEG, symname)) {
 898				add_reloc(&relocs16, rel->r_offset);
 899				break;
 900			}
 901		} else {
 902			if (!is_reloc(S_LIN, symname))
 903				break;
 904		}
 905		die("Invalid %s %s relocation: %s\n",
 906		    shn_abs ? "absolute" : "relative",
 907		    rel_type(r_type), symname);
 908		break;
 909
 910	case R_386_32:
 911		if (shn_abs) {
 912			/*
 913			 * Whitelisted absolute symbols do not require
 914			 * relocation.
 915			 */
 916			if (is_reloc(S_ABS, symname))
 917				break;
 918
 919			if (is_reloc(S_REL, symname)) {
 920				add_reloc(&relocs32, rel->r_offset);
 921				break;
 922			}
 923		} else {
 924			if (is_reloc(S_LIN, symname))
 925				add_reloc(&relocs32, rel->r_offset);
 926			break;
 927		}
 928		die("Invalid %s %s relocation: %s\n",
 929		    shn_abs ? "absolute" : "relative",
 930		    rel_type(r_type), symname);
 931		break;
 932
 933	default:
 934		die("Unsupported relocation type: %s (%d)\n",
 935		    rel_type(r_type), r_type);
 936		break;
 937	}
 938
 939	return 0;
 940}
 941
 942#endif
 943
 944static int cmp_relocs(const void *va, const void *vb)
 945{
 946	const uint32_t *a, *b;
 947	a = va; b = vb;
 948	return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 949}
 950
 951static void sort_relocs(struct relocs *r)
 952{
 953	qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
 954}
 955
 956static int write32(uint32_t v, FILE *f)
 957{
 958	unsigned char buf[4];
 959
 960	put_unaligned_le32(v, buf);
 961	return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 962}
 963
 964static int write32_as_text(uint32_t v, FILE *f)
 965{
 966	return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
 967}
 968
 969static void emit_relocs(int as_text, int use_real_mode)
 970{
 971	int i;
 972	int (*write_reloc)(uint32_t, FILE *) = write32;
 973	int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 974			const char *symname);
 975
 976#if ELF_BITS == 64
 977	if (!use_real_mode)
 978		do_reloc = do_reloc64;
 979	else
 980		die("--realmode not valid for a 64-bit ELF file");
 981#else
 982	if (!use_real_mode)
 983		do_reloc = do_reloc32;
 984	else
 985		do_reloc = do_reloc_real;
 986#endif
 987
 988	/* Collect up the relocations */
 989	walk_relocs(do_reloc);
 990
 991	if (relocs16.count && !use_real_mode)
 992		die("Segment relocations found but --realmode not specified\n");
 993
 994	/* Order the relocations for more efficient processing */
 995	sort_relocs(&relocs32);
 996#if ELF_BITS == 64
 997	sort_relocs(&relocs32neg);
 998	sort_relocs(&relocs64);
 999#else
1000	sort_relocs(&relocs16);
1001#endif
1002
1003	/* Print the relocations */
1004	if (as_text) {
1005		/* Print the relocations in a form suitable that
1006		 * gas will like.
1007		 */
1008		printf(".section \".data.reloc\",\"a\"\n");
1009		printf(".balign 4\n");
1010		write_reloc = write32_as_text;
1011	}
1012
1013	if (use_real_mode) {
1014		write_reloc(relocs16.count, stdout);
1015		for (i = 0; i < relocs16.count; i++)
1016			write_reloc(relocs16.offset[i], stdout);
1017
1018		write_reloc(relocs32.count, stdout);
1019		for (i = 0; i < relocs32.count; i++)
1020			write_reloc(relocs32.offset[i], stdout);
1021	} else {
1022#if ELF_BITS == 64
1023		/* Print a stop */
1024		write_reloc(0, stdout);
1025
1026		/* Now print each relocation */
1027		for (i = 0; i < relocs64.count; i++)
1028			write_reloc(relocs64.offset[i], stdout);
1029
1030		/* Print a stop */
1031		write_reloc(0, stdout);
1032
1033		/* Now print each inverse 32-bit relocation */
1034		for (i = 0; i < relocs32neg.count; i++)
1035			write_reloc(relocs32neg.offset[i], stdout);
1036#endif
1037
1038		/* Print a stop */
1039		write_reloc(0, stdout);
1040
1041		/* Now print each relocation */
1042		for (i = 0; i < relocs32.count; i++)
1043			write_reloc(relocs32.offset[i], stdout);
1044	}
1045}
1046
1047/*
1048 * As an aid to debugging problems with different linkers
1049 * print summary information about the relocs.
1050 * Since different linkers tend to emit the sections in
1051 * different orders we use the section names in the output.
1052 */
1053static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1054				const char *symname)
1055{
1056	printf("%s\t%s\t%s\t%s\n",
1057		sec_name(sec->shdr.sh_info),
1058		rel_type(ELF_R_TYPE(rel->r_info)),
1059		symname,
1060		sec_name(sym->st_shndx));
1061	return 0;
1062}
1063
1064static void print_reloc_info(void)
1065{
1066	printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1067	walk_relocs(do_reloc_info);
1068}
1069
1070#if ELF_BITS == 64
1071# define process process_64
1072#else
1073# define process process_32
1074#endif
1075
1076void process(FILE *fp, int use_real_mode, int as_text,
1077	     int show_absolute_syms, int show_absolute_relocs,
1078	     int show_reloc_info)
1079{
1080	regex_init(use_real_mode);
1081	read_ehdr(fp);
1082	read_shdrs(fp);
1083	read_strtabs(fp);
1084	read_symtabs(fp);
1085	read_relocs(fp);
1086	if (ELF_BITS == 64)
1087		percpu_init();
1088	if (show_absolute_syms) {
1089		print_absolute_symbols();
1090		return;
1091	}
1092	if (show_absolute_relocs) {
1093		print_absolute_relocs();
1094		return;
1095	}
1096	if (show_reloc_info) {
1097		print_reloc_info();
1098		return;
1099	}
1100	emit_relocs(as_text, use_real_mode);
1101}
v5.4
   1// SPDX-License-Identifier: GPL-2.0
   2/* This is included from relocs_32/64.c */
   3
   4#define ElfW(type)		_ElfW(ELF_BITS, type)
   5#define _ElfW(bits, type)	__ElfW(bits, type)
   6#define __ElfW(bits, type)	Elf##bits##_##type
   7
   8#define Elf_Addr		ElfW(Addr)
   9#define Elf_Ehdr		ElfW(Ehdr)
  10#define Elf_Phdr		ElfW(Phdr)
  11#define Elf_Shdr		ElfW(Shdr)
  12#define Elf_Sym			ElfW(Sym)
  13
  14static Elf_Ehdr		ehdr;
  15static unsigned long	shnum;
  16static unsigned int	shstrndx;
  17
  18struct relocs {
  19	uint32_t	*offset;
  20	unsigned long	count;
  21	unsigned long	size;
  22};
  23
  24static struct relocs relocs16;
  25static struct relocs relocs32;
  26#if ELF_BITS == 64
  27static struct relocs relocs32neg;
  28static struct relocs relocs64;
  29#endif
  30
  31struct section {
  32	Elf_Shdr       shdr;
  33	struct section *link;
  34	Elf_Sym        *symtab;
  35	Elf_Rel        *reltab;
  36	char           *strtab;
  37};
  38static struct section *secs;
  39
  40static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  41/*
  42 * Following symbols have been audited. There values are constant and do
  43 * not change if bzImage is loaded at a different physical address than
  44 * the address for which it has been compiled. Don't warn user about
  45 * absolute relocations present w.r.t these symbols.
  46 */
  47	[S_ABS] =
  48	"^(xen_irq_disable_direct_reloc$|"
  49	"xen_save_fl_direct_reloc$|"
  50	"VDSO|"
  51	"__crc_)",
  52
  53/*
  54 * These symbols are known to be relative, even if the linker marks them
  55 * as absolute (typically defined outside any section in the linker script.)
  56 */
  57	[S_REL] =
  58	"^(__init_(begin|end)|"
  59	"__x86_cpu_dev_(start|end)|"
  60	"(__parainstructions|__alt_instructions)(|_end)|"
  61	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
  62	"__(start|end)_pci_.*|"
  63	"__(start|end)_builtin_fw|"
  64	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  65	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  66	"__(start|stop)___param|"
  67	"__(start|stop)___modver|"
  68	"__(start|stop)___bug_table|"
  69	"__tracedata_(start|end)|"
  70	"__(start|stop)_notes|"
  71	"__end_rodata|"
  72	"__end_rodata_aligned|"
  73	"__initramfs_start|"
  74	"(jiffies|jiffies_64)|"
  75#if ELF_BITS == 64
  76	"__per_cpu_load|"
  77	"init_per_cpu__.*|"
  78	"__end_rodata_hpage_align|"
  79#endif
  80	"__vvar_page|"
  81	"_end)$"
  82};
  83
  84
  85static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  86/*
  87 * These symbols are known to be relative, even if the linker marks them
  88 * as absolute (typically defined outside any section in the linker script.)
  89 */
  90	[S_REL] =
  91	"^pa_",
  92
  93/*
  94 * These are 16-bit segment symbols when compiling 16-bit code.
  95 */
  96	[S_SEG] =
  97	"^real_mode_seg$",
  98
  99/*
 100 * These are offsets belonging to segments, as opposed to linear addresses,
 101 * when compiling 16-bit code.
 102 */
 103	[S_LIN] =
 104	"^pa_",
 105};
 106
 107static const char * const *sym_regex;
 108
 109static regex_t sym_regex_c[S_NSYMTYPES];
 110static int is_reloc(enum symtype type, const char *sym_name)
 111{
 112	return sym_regex[type] &&
 113		!regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
 114}
 115
 116static void regex_init(int use_real_mode)
 117{
 118        char errbuf[128];
 119        int err;
 120	int i;
 121
 122	if (use_real_mode)
 123		sym_regex = sym_regex_realmode;
 124	else
 125		sym_regex = sym_regex_kernel;
 126
 127	for (i = 0; i < S_NSYMTYPES; i++) {
 128		if (!sym_regex[i])
 129			continue;
 130
 131		err = regcomp(&sym_regex_c[i], sym_regex[i],
 132			      REG_EXTENDED|REG_NOSUB);
 133
 134		if (err) {
 135			regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf));
 136			die("%s", errbuf);
 137		}
 138        }
 139}
 140
 141static const char *sym_type(unsigned type)
 142{
 143	static const char *type_name[] = {
 144#define SYM_TYPE(X) [X] = #X
 145		SYM_TYPE(STT_NOTYPE),
 146		SYM_TYPE(STT_OBJECT),
 147		SYM_TYPE(STT_FUNC),
 148		SYM_TYPE(STT_SECTION),
 149		SYM_TYPE(STT_FILE),
 150		SYM_TYPE(STT_COMMON),
 151		SYM_TYPE(STT_TLS),
 152#undef SYM_TYPE
 153	};
 154	const char *name = "unknown sym type name";
 155	if (type < ARRAY_SIZE(type_name)) {
 156		name = type_name[type];
 157	}
 158	return name;
 159}
 160
 161static const char *sym_bind(unsigned bind)
 162{
 163	static const char *bind_name[] = {
 164#define SYM_BIND(X) [X] = #X
 165		SYM_BIND(STB_LOCAL),
 166		SYM_BIND(STB_GLOBAL),
 167		SYM_BIND(STB_WEAK),
 168#undef SYM_BIND
 169	};
 170	const char *name = "unknown sym bind name";
 171	if (bind < ARRAY_SIZE(bind_name)) {
 172		name = bind_name[bind];
 173	}
 174	return name;
 175}
 176
 177static const char *sym_visibility(unsigned visibility)
 178{
 179	static const char *visibility_name[] = {
 180#define SYM_VISIBILITY(X) [X] = #X
 181		SYM_VISIBILITY(STV_DEFAULT),
 182		SYM_VISIBILITY(STV_INTERNAL),
 183		SYM_VISIBILITY(STV_HIDDEN),
 184		SYM_VISIBILITY(STV_PROTECTED),
 185#undef SYM_VISIBILITY
 186	};
 187	const char *name = "unknown sym visibility name";
 188	if (visibility < ARRAY_SIZE(visibility_name)) {
 189		name = visibility_name[visibility];
 190	}
 191	return name;
 192}
 193
 194static const char *rel_type(unsigned type)
 195{
 196	static const char *type_name[] = {
 197#define REL_TYPE(X) [X] = #X
 198#if ELF_BITS == 64
 199		REL_TYPE(R_X86_64_NONE),
 200		REL_TYPE(R_X86_64_64),
 201		REL_TYPE(R_X86_64_PC64),
 202		REL_TYPE(R_X86_64_PC32),
 203		REL_TYPE(R_X86_64_GOT32),
 204		REL_TYPE(R_X86_64_PLT32),
 205		REL_TYPE(R_X86_64_COPY),
 206		REL_TYPE(R_X86_64_GLOB_DAT),
 207		REL_TYPE(R_X86_64_JUMP_SLOT),
 208		REL_TYPE(R_X86_64_RELATIVE),
 209		REL_TYPE(R_X86_64_GOTPCREL),
 210		REL_TYPE(R_X86_64_32),
 211		REL_TYPE(R_X86_64_32S),
 212		REL_TYPE(R_X86_64_16),
 213		REL_TYPE(R_X86_64_PC16),
 214		REL_TYPE(R_X86_64_8),
 215		REL_TYPE(R_X86_64_PC8),
 216#else
 217		REL_TYPE(R_386_NONE),
 218		REL_TYPE(R_386_32),
 219		REL_TYPE(R_386_PC32),
 220		REL_TYPE(R_386_GOT32),
 221		REL_TYPE(R_386_PLT32),
 222		REL_TYPE(R_386_COPY),
 223		REL_TYPE(R_386_GLOB_DAT),
 224		REL_TYPE(R_386_JMP_SLOT),
 225		REL_TYPE(R_386_RELATIVE),
 226		REL_TYPE(R_386_GOTOFF),
 227		REL_TYPE(R_386_GOTPC),
 228		REL_TYPE(R_386_8),
 229		REL_TYPE(R_386_PC8),
 230		REL_TYPE(R_386_16),
 231		REL_TYPE(R_386_PC16),
 232#endif
 233#undef REL_TYPE
 234	};
 235	const char *name = "unknown type rel type name";
 236	if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 237		name = type_name[type];
 238	}
 239	return name;
 240}
 241
 242static const char *sec_name(unsigned shndx)
 243{
 244	const char *sec_strtab;
 245	const char *name;
 246	sec_strtab = secs[shstrndx].strtab;
 247	name = "<noname>";
 248	if (shndx < shnum) {
 249		name = sec_strtab + secs[shndx].shdr.sh_name;
 250	}
 251	else if (shndx == SHN_ABS) {
 252		name = "ABSOLUTE";
 253	}
 254	else if (shndx == SHN_COMMON) {
 255		name = "COMMON";
 256	}
 257	return name;
 258}
 259
 260static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
 261{
 262	const char *name;
 263	name = "<noname>";
 264	if (sym->st_name) {
 265		name = sym_strtab + sym->st_name;
 266	}
 267	else {
 268		name = sec_name(sym->st_shndx);
 269	}
 270	return name;
 271}
 272
 273static Elf_Sym *sym_lookup(const char *symname)
 274{
 275	int i;
 276	for (i = 0; i < shnum; i++) {
 277		struct section *sec = &secs[i];
 278		long nsyms;
 279		char *strtab;
 280		Elf_Sym *symtab;
 281		Elf_Sym *sym;
 282
 283		if (sec->shdr.sh_type != SHT_SYMTAB)
 284			continue;
 285
 286		nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
 287		symtab = sec->symtab;
 288		strtab = sec->link->strtab;
 289
 290		for (sym = symtab; --nsyms >= 0; sym++) {
 291			if (!sym->st_name)
 292				continue;
 293			if (strcmp(symname, strtab + sym->st_name) == 0)
 294				return sym;
 295		}
 296	}
 297	return 0;
 298}
 299
 300#if BYTE_ORDER == LITTLE_ENDIAN
 301#define le16_to_cpu(val) (val)
 302#define le32_to_cpu(val) (val)
 303#define le64_to_cpu(val) (val)
 304#endif
 305#if BYTE_ORDER == BIG_ENDIAN
 306#define le16_to_cpu(val) bswap_16(val)
 307#define le32_to_cpu(val) bswap_32(val)
 308#define le64_to_cpu(val) bswap_64(val)
 309#endif
 310
 311static uint16_t elf16_to_cpu(uint16_t val)
 312{
 313	return le16_to_cpu(val);
 314}
 315
 316static uint32_t elf32_to_cpu(uint32_t val)
 317{
 318	return le32_to_cpu(val);
 319}
 320
 321#define elf_half_to_cpu(x)	elf16_to_cpu(x)
 322#define elf_word_to_cpu(x)	elf32_to_cpu(x)
 323
 324#if ELF_BITS == 64
 325static uint64_t elf64_to_cpu(uint64_t val)
 326{
 327        return le64_to_cpu(val);
 328}
 329#define elf_addr_to_cpu(x)	elf64_to_cpu(x)
 330#define elf_off_to_cpu(x)	elf64_to_cpu(x)
 331#define elf_xword_to_cpu(x)	elf64_to_cpu(x)
 332#else
 333#define elf_addr_to_cpu(x)	elf32_to_cpu(x)
 334#define elf_off_to_cpu(x)	elf32_to_cpu(x)
 335#define elf_xword_to_cpu(x)	elf32_to_cpu(x)
 336#endif
 337
 338static void read_ehdr(FILE *fp)
 339{
 340	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 341		die("Cannot read ELF header: %s\n",
 342			strerror(errno));
 343	}
 344	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 345		die("No ELF magic\n");
 346	}
 347	if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
 348		die("Not a %d bit executable\n", ELF_BITS);
 349	}
 350	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 351		die("Not a LSB ELF executable\n");
 352	}
 353	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 354		die("Unknown ELF version\n");
 355	}
 356	/* Convert the fields to native endian */
 357	ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
 358	ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
 359	ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
 360	ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
 361	ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
 362	ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
 363	ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
 364	ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
 365	ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
 366	ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
 367	ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
 368	ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
 369	ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);
 370
 371	shnum = ehdr.e_shnum;
 372	shstrndx = ehdr.e_shstrndx;
 373
 374	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
 375		die("Unsupported ELF header type\n");
 376	if (ehdr.e_machine != ELF_MACHINE)
 
 377		die("Not for %s\n", ELF_MACHINE_NAME);
 378	if (ehdr.e_version != EV_CURRENT)
 
 379		die("Unknown ELF version\n");
 380	if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
 
 381		die("Bad Elf header size\n");
 382	if (ehdr.e_phentsize != sizeof(Elf_Phdr))
 
 383		die("Bad program header entry\n");
 384	if (ehdr.e_shentsize != sizeof(Elf_Shdr))
 
 385		die("Bad section header entry\n");
 386
 387
 388	if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
 389		Elf_Shdr shdr;
 390
 391		if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
 392			die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));
 393
 394		if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 395			die("Cannot read initial ELF section header: %s\n", strerror(errno));
 396
 397		if (shnum == SHN_UNDEF)
 398			shnum = elf_xword_to_cpu(shdr.sh_size);
 399
 400		if (shstrndx == SHN_XINDEX)
 401			shstrndx = elf_word_to_cpu(shdr.sh_link);
 402	}
 403
 404	if (shstrndx >= shnum)
 405		die("String table index out of bounds\n");
 
 406}
 407
 408static void read_shdrs(FILE *fp)
 409{
 410	int i;
 411	Elf_Shdr shdr;
 412
 413	secs = calloc(shnum, sizeof(struct section));
 414	if (!secs) {
 415		die("Unable to allocate %d section headers\n",
 416		    shnum);
 417	}
 418	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 419		die("Seek to %d failed: %s\n",
 420			ehdr.e_shoff, strerror(errno));
 421	}
 422	for (i = 0; i < shnum; i++) {
 423		struct section *sec = &secs[i];
 424		if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 425			die("Cannot read ELF section headers %d/%d: %s\n",
 426			    i, shnum, strerror(errno));
 427		sec->shdr.sh_name      = elf_word_to_cpu(shdr.sh_name);
 428		sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
 429		sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
 430		sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
 431		sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
 432		sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
 433		sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
 434		sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
 435		sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
 436		sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
 437		if (sec->shdr.sh_link < shnum)
 438			sec->link = &secs[sec->shdr.sh_link];
 439	}
 440
 441}
 442
 443static void read_strtabs(FILE *fp)
 444{
 445	int i;
 446	for (i = 0; i < shnum; i++) {
 447		struct section *sec = &secs[i];
 448		if (sec->shdr.sh_type != SHT_STRTAB) {
 449			continue;
 450		}
 451		sec->strtab = malloc(sec->shdr.sh_size);
 452		if (!sec->strtab) {
 453			die("malloc of %d bytes for strtab failed\n",
 454				sec->shdr.sh_size);
 455		}
 456		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 457			die("Seek to %d failed: %s\n",
 458				sec->shdr.sh_offset, strerror(errno));
 459		}
 460		if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 461		    != sec->shdr.sh_size) {
 462			die("Cannot read symbol table: %s\n",
 463				strerror(errno));
 464		}
 465	}
 466}
 467
 468static void read_symtabs(FILE *fp)
 469{
 470	int i,j;
 471	for (i = 0; i < shnum; i++) {
 472		struct section *sec = &secs[i];
 473		if (sec->shdr.sh_type != SHT_SYMTAB) {
 474			continue;
 475		}
 476		sec->symtab = malloc(sec->shdr.sh_size);
 477		if (!sec->symtab) {
 478			die("malloc of %d bytes for symtab failed\n",
 479				sec->shdr.sh_size);
 480		}
 481		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 482			die("Seek to %d failed: %s\n",
 483				sec->shdr.sh_offset, strerror(errno));
 484		}
 485		if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 486		    != sec->shdr.sh_size) {
 487			die("Cannot read symbol table: %s\n",
 488				strerror(errno));
 489		}
 490		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
 491			Elf_Sym *sym = &sec->symtab[j];
 492			sym->st_name  = elf_word_to_cpu(sym->st_name);
 493			sym->st_value = elf_addr_to_cpu(sym->st_value);
 494			sym->st_size  = elf_xword_to_cpu(sym->st_size);
 495			sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
 496		}
 497	}
 498}
 499
 500
 501static void read_relocs(FILE *fp)
 502{
 503	int i,j;
 504	for (i = 0; i < shnum; i++) {
 505		struct section *sec = &secs[i];
 506		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 507			continue;
 508		}
 509		sec->reltab = malloc(sec->shdr.sh_size);
 510		if (!sec->reltab) {
 511			die("malloc of %d bytes for relocs failed\n",
 512				sec->shdr.sh_size);
 513		}
 514		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 515			die("Seek to %d failed: %s\n",
 516				sec->shdr.sh_offset, strerror(errno));
 517		}
 518		if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 519		    != sec->shdr.sh_size) {
 520			die("Cannot read symbol table: %s\n",
 521				strerror(errno));
 522		}
 523		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 524			Elf_Rel *rel = &sec->reltab[j];
 525			rel->r_offset = elf_addr_to_cpu(rel->r_offset);
 526			rel->r_info   = elf_xword_to_cpu(rel->r_info);
 527#if (SHT_REL_TYPE == SHT_RELA)
 528			rel->r_addend = elf_xword_to_cpu(rel->r_addend);
 529#endif
 530		}
 531	}
 532}
 533
 534
 535static void print_absolute_symbols(void)
 536{
 537	int i;
 538	const char *format;
 539
 540	if (ELF_BITS == 64)
 541		format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
 542	else
 543		format = "%5d %08"PRIx32"  %5"PRId32" %10s %10s %12s %s\n";
 544
 545	printf("Absolute symbols\n");
 546	printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 547	for (i = 0; i < shnum; i++) {
 548		struct section *sec = &secs[i];
 549		char *sym_strtab;
 550		int j;
 551
 552		if (sec->shdr.sh_type != SHT_SYMTAB) {
 553			continue;
 554		}
 555		sym_strtab = sec->link->strtab;
 556		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
 557			Elf_Sym *sym;
 558			const char *name;
 559			sym = &sec->symtab[j];
 560			name = sym_name(sym_strtab, sym);
 561			if (sym->st_shndx != SHN_ABS) {
 562				continue;
 563			}
 564			printf(format,
 565				j, sym->st_value, sym->st_size,
 566				sym_type(ELF_ST_TYPE(sym->st_info)),
 567				sym_bind(ELF_ST_BIND(sym->st_info)),
 568				sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
 569				name);
 570		}
 571	}
 572	printf("\n");
 573}
 574
 575static void print_absolute_relocs(void)
 576{
 577	int i, printed = 0;
 578	const char *format;
 579
 580	if (ELF_BITS == 64)
 581		format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64"  %s\n";
 582	else
 583		format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32"  %s\n";
 584
 585	for (i = 0; i < shnum; i++) {
 586		struct section *sec = &secs[i];
 587		struct section *sec_applies, *sec_symtab;
 588		char *sym_strtab;
 589		Elf_Sym *sh_symtab;
 590		int j;
 591		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 592			continue;
 593		}
 594		sec_symtab  = sec->link;
 595		sec_applies = &secs[sec->shdr.sh_info];
 596		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 597			continue;
 598		}
 599		sh_symtab  = sec_symtab->symtab;
 600		sym_strtab = sec_symtab->link->strtab;
 601		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 602			Elf_Rel *rel;
 603			Elf_Sym *sym;
 604			const char *name;
 605			rel = &sec->reltab[j];
 606			sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 607			name = sym_name(sym_strtab, sym);
 608			if (sym->st_shndx != SHN_ABS) {
 609				continue;
 610			}
 611
 612			/* Absolute symbols are not relocated if bzImage is
 613			 * loaded at a non-compiled address. Display a warning
 614			 * to user at compile time about the absolute
 615			 * relocations present.
 616			 *
 617			 * User need to audit the code to make sure
 618			 * some symbols which should have been section
 619			 * relative have not become absolute because of some
 620			 * linker optimization or wrong programming usage.
 621			 *
 622			 * Before warning check if this absolute symbol
 623			 * relocation is harmless.
 624			 */
 625			if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 626				continue;
 627
 628			if (!printed) {
 629				printf("WARNING: Absolute relocations"
 630					" present\n");
 631				printf("Offset     Info     Type     Sym.Value "
 632					"Sym.Name\n");
 633				printed = 1;
 634			}
 635
 636			printf(format,
 637				rel->r_offset,
 638				rel->r_info,
 639				rel_type(ELF_R_TYPE(rel->r_info)),
 640				sym->st_value,
 641				name);
 642		}
 643	}
 644
 645	if (printed)
 646		printf("\n");
 647}
 648
 649static void add_reloc(struct relocs *r, uint32_t offset)
 650{
 651	if (r->count == r->size) {
 652		unsigned long newsize = r->size + 50000;
 653		void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
 654
 655		if (!mem)
 656			die("realloc of %ld entries for relocs failed\n",
 657                                newsize);
 658		r->offset = mem;
 659		r->size = newsize;
 660	}
 661	r->offset[r->count++] = offset;
 662}
 663
 664static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 665			Elf_Sym *sym, const char *symname))
 666{
 667	int i;
 668	/* Walk through the relocations */
 669	for (i = 0; i < shnum; i++) {
 670		char *sym_strtab;
 671		Elf_Sym *sh_symtab;
 672		struct section *sec_applies, *sec_symtab;
 673		int j;
 674		struct section *sec = &secs[i];
 675
 676		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 677			continue;
 678		}
 679		sec_symtab  = sec->link;
 680		sec_applies = &secs[sec->shdr.sh_info];
 681		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 682			continue;
 683		}
 684		sh_symtab = sec_symtab->symtab;
 685		sym_strtab = sec_symtab->link->strtab;
 686		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 687			Elf_Rel *rel = &sec->reltab[j];
 688			Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 689			const char *symname = sym_name(sym_strtab, sym);
 690
 691			process(sec, rel, sym, symname);
 692		}
 693	}
 694}
 695
 696/*
 697 * The .data..percpu section is a special case for x86_64 SMP kernels.
 698 * It is used to initialize the actual per_cpu areas and to provide
 699 * definitions for the per_cpu variables that correspond to their offsets
 700 * within the percpu area. Since the values of all of the symbols need
 701 * to be offsets from the start of the per_cpu area the virtual address
 702 * (sh_addr) of .data..percpu is 0 in SMP kernels.
 703 *
 704 * This means that:
 705 *
 706 *	Relocations that reference symbols in the per_cpu area do not
 707 *	need further relocation (since the value is an offset relative
 708 *	to the start of the per_cpu area that does not change).
 709 *
 710 *	Relocations that apply to the per_cpu area need to have their
 711 *	offset adjusted by by the value of __per_cpu_load to make them
 712 *	point to the correct place in the loaded image (because the
 713 *	virtual address of .data..percpu is 0).
 714 *
 715 * For non SMP kernels .data..percpu is linked as part of the normal
 716 * kernel data and does not require special treatment.
 717 *
 718 */
 719static int per_cpu_shndx	= -1;
 720static Elf_Addr per_cpu_load_addr;
 721
 722static void percpu_init(void)
 723{
 724	int i;
 725	for (i = 0; i < shnum; i++) {
 726		ElfW(Sym) *sym;
 727		if (strcmp(sec_name(i), ".data..percpu"))
 728			continue;
 729
 730		if (secs[i].shdr.sh_addr != 0)	/* non SMP kernel */
 731			return;
 732
 733		sym = sym_lookup("__per_cpu_load");
 734		if (!sym)
 735			die("can't find __per_cpu_load\n");
 736
 737		per_cpu_shndx = i;
 738		per_cpu_load_addr = sym->st_value;
 739		return;
 740	}
 741}
 742
 743#if ELF_BITS == 64
 744
 745/*
 746 * Check to see if a symbol lies in the .data..percpu section.
 747 *
 748 * The linker incorrectly associates some symbols with the
 749 * .data..percpu section so we also need to check the symbol
 750 * name to make sure that we classify the symbol correctly.
 751 *
 752 * The GNU linker incorrectly associates:
 753 *	__init_begin
 754 *	__per_cpu_load
 755 *
 756 * The "gold" linker incorrectly associates:
 757 *	init_per_cpu__fixed_percpu_data
 758 *	init_per_cpu__gdt_page
 759 */
 760static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
 761{
 762	return (sym->st_shndx == per_cpu_shndx) &&
 763		strcmp(symname, "__init_begin") &&
 764		strcmp(symname, "__per_cpu_load") &&
 765		strncmp(symname, "init_per_cpu_", 13);
 766}
 767
 768
 769static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 770		      const char *symname)
 771{
 772	unsigned r_type = ELF64_R_TYPE(rel->r_info);
 773	ElfW(Addr) offset = rel->r_offset;
 774	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 775
 776	if (sym->st_shndx == SHN_UNDEF)
 777		return 0;
 778
 779	/*
 780	 * Adjust the offset if this reloc applies to the percpu section.
 781	 */
 782	if (sec->shdr.sh_info == per_cpu_shndx)
 783		offset += per_cpu_load_addr;
 784
 785	switch (r_type) {
 786	case R_X86_64_NONE:
 787		/* NONE can be ignored. */
 788		break;
 789
 790	case R_X86_64_PC32:
 791	case R_X86_64_PLT32:
 792		/*
 793		 * PC relative relocations don't need to be adjusted unless
 794		 * referencing a percpu symbol.
 795		 *
 796		 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
 797		 */
 798		if (is_percpu_sym(sym, symname))
 799			add_reloc(&relocs32neg, offset);
 800		break;
 801
 802	case R_X86_64_PC64:
 803		/*
 804		 * Only used by jump labels
 805		 */
 806		if (is_percpu_sym(sym, symname))
 807			die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
 808			    symname);
 809		break;
 810
 811	case R_X86_64_32:
 812	case R_X86_64_32S:
 813	case R_X86_64_64:
 814		/*
 815		 * References to the percpu area don't need to be adjusted.
 816		 */
 817		if (is_percpu_sym(sym, symname))
 818			break;
 819
 820		if (shn_abs) {
 821			/*
 822			 * Whitelisted absolute symbols do not require
 823			 * relocation.
 824			 */
 825			if (is_reloc(S_ABS, symname))
 826				break;
 827
 828			die("Invalid absolute %s relocation: %s\n",
 829			    rel_type(r_type), symname);
 830			break;
 831		}
 832
 833		/*
 834		 * Relocation offsets for 64 bit kernels are output
 835		 * as 32 bits and sign extended back to 64 bits when
 836		 * the relocations are processed.
 837		 * Make sure that the offset will fit.
 838		 */
 839		if ((int32_t)offset != (int64_t)offset)
 840			die("Relocation offset doesn't fit in 32 bits\n");
 841
 842		if (r_type == R_X86_64_64)
 843			add_reloc(&relocs64, offset);
 844		else
 845			add_reloc(&relocs32, offset);
 846		break;
 847
 848	default:
 849		die("Unsupported relocation type: %s (%d)\n",
 850		    rel_type(r_type), r_type);
 851		break;
 852	}
 853
 854	return 0;
 855}
 856
 857#else
 858
 859static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 860		      const char *symname)
 861{
 862	unsigned r_type = ELF32_R_TYPE(rel->r_info);
 863	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 864
 865	switch (r_type) {
 866	case R_386_NONE:
 867	case R_386_PC32:
 868	case R_386_PC16:
 869	case R_386_PC8:
 870		/*
 871		 * NONE can be ignored and PC relative relocations don't
 872		 * need to be adjusted.
 873		 */
 874		break;
 875
 876	case R_386_32:
 877		if (shn_abs) {
 878			/*
 879			 * Whitelisted absolute symbols do not require
 880			 * relocation.
 881			 */
 882			if (is_reloc(S_ABS, symname))
 883				break;
 884
 885			die("Invalid absolute %s relocation: %s\n",
 886			    rel_type(r_type), symname);
 887			break;
 888		}
 889
 890		add_reloc(&relocs32, rel->r_offset);
 891		break;
 892
 893	default:
 894		die("Unsupported relocation type: %s (%d)\n",
 895		    rel_type(r_type), r_type);
 896		break;
 897	}
 898
 899	return 0;
 900}
 901
 902static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 903			 const char *symname)
 904{
 905	unsigned r_type = ELF32_R_TYPE(rel->r_info);
 906	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 907
 908	switch (r_type) {
 909	case R_386_NONE:
 910	case R_386_PC32:
 911	case R_386_PC16:
 912	case R_386_PC8:
 913		/*
 914		 * NONE can be ignored and PC relative relocations don't
 915		 * need to be adjusted.
 916		 */
 917		break;
 918
 919	case R_386_16:
 920		if (shn_abs) {
 921			/*
 922			 * Whitelisted absolute symbols do not require
 923			 * relocation.
 924			 */
 925			if (is_reloc(S_ABS, symname))
 926				break;
 927
 928			if (is_reloc(S_SEG, symname)) {
 929				add_reloc(&relocs16, rel->r_offset);
 930				break;
 931			}
 932		} else {
 933			if (!is_reloc(S_LIN, symname))
 934				break;
 935		}
 936		die("Invalid %s %s relocation: %s\n",
 937		    shn_abs ? "absolute" : "relative",
 938		    rel_type(r_type), symname);
 939		break;
 940
 941	case R_386_32:
 942		if (shn_abs) {
 943			/*
 944			 * Whitelisted absolute symbols do not require
 945			 * relocation.
 946			 */
 947			if (is_reloc(S_ABS, symname))
 948				break;
 949
 950			if (is_reloc(S_REL, symname)) {
 951				add_reloc(&relocs32, rel->r_offset);
 952				break;
 953			}
 954		} else {
 955			if (is_reloc(S_LIN, symname))
 956				add_reloc(&relocs32, rel->r_offset);
 957			break;
 958		}
 959		die("Invalid %s %s relocation: %s\n",
 960		    shn_abs ? "absolute" : "relative",
 961		    rel_type(r_type), symname);
 962		break;
 963
 964	default:
 965		die("Unsupported relocation type: %s (%d)\n",
 966		    rel_type(r_type), r_type);
 967		break;
 968	}
 969
 970	return 0;
 971}
 972
 973#endif
 974
 975static int cmp_relocs(const void *va, const void *vb)
 976{
 977	const uint32_t *a, *b;
 978	a = va; b = vb;
 979	return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 980}
 981
 982static void sort_relocs(struct relocs *r)
 983{
 984	qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
 985}
 986
 987static int write32(uint32_t v, FILE *f)
 988{
 989	unsigned char buf[4];
 990
 991	put_unaligned_le32(v, buf);
 992	return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 993}
 994
 995static int write32_as_text(uint32_t v, FILE *f)
 996{
 997	return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
 998}
 999
1000static void emit_relocs(int as_text, int use_real_mode)
1001{
1002	int i;
1003	int (*write_reloc)(uint32_t, FILE *) = write32;
1004	int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
1005			const char *symname);
1006
1007#if ELF_BITS == 64
1008	if (!use_real_mode)
1009		do_reloc = do_reloc64;
1010	else
1011		die("--realmode not valid for a 64-bit ELF file");
1012#else
1013	if (!use_real_mode)
1014		do_reloc = do_reloc32;
1015	else
1016		do_reloc = do_reloc_real;
1017#endif
1018
1019	/* Collect up the relocations */
1020	walk_relocs(do_reloc);
1021
1022	if (relocs16.count && !use_real_mode)
1023		die("Segment relocations found but --realmode not specified\n");
1024
1025	/* Order the relocations for more efficient processing */
1026	sort_relocs(&relocs32);
1027#if ELF_BITS == 64
1028	sort_relocs(&relocs32neg);
1029	sort_relocs(&relocs64);
1030#else
1031	sort_relocs(&relocs16);
1032#endif
1033
1034	/* Print the relocations */
1035	if (as_text) {
1036		/* Print the relocations in a form suitable that
1037		 * gas will like.
1038		 */
1039		printf(".section \".data.reloc\",\"a\"\n");
1040		printf(".balign 4\n");
1041		write_reloc = write32_as_text;
1042	}
1043
1044	if (use_real_mode) {
1045		write_reloc(relocs16.count, stdout);
1046		for (i = 0; i < relocs16.count; i++)
1047			write_reloc(relocs16.offset[i], stdout);
1048
1049		write_reloc(relocs32.count, stdout);
1050		for (i = 0; i < relocs32.count; i++)
1051			write_reloc(relocs32.offset[i], stdout);
1052	} else {
1053#if ELF_BITS == 64
1054		/* Print a stop */
1055		write_reloc(0, stdout);
1056
1057		/* Now print each relocation */
1058		for (i = 0; i < relocs64.count; i++)
1059			write_reloc(relocs64.offset[i], stdout);
1060
1061		/* Print a stop */
1062		write_reloc(0, stdout);
1063
1064		/* Now print each inverse 32-bit relocation */
1065		for (i = 0; i < relocs32neg.count; i++)
1066			write_reloc(relocs32neg.offset[i], stdout);
1067#endif
1068
1069		/* Print a stop */
1070		write_reloc(0, stdout);
1071
1072		/* Now print each relocation */
1073		for (i = 0; i < relocs32.count; i++)
1074			write_reloc(relocs32.offset[i], stdout);
1075	}
1076}
1077
1078/*
1079 * As an aid to debugging problems with different linkers
1080 * print summary information about the relocs.
1081 * Since different linkers tend to emit the sections in
1082 * different orders we use the section names in the output.
1083 */
1084static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1085				const char *symname)
1086{
1087	printf("%s\t%s\t%s\t%s\n",
1088		sec_name(sec->shdr.sh_info),
1089		rel_type(ELF_R_TYPE(rel->r_info)),
1090		symname,
1091		sec_name(sym->st_shndx));
1092	return 0;
1093}
1094
1095static void print_reloc_info(void)
1096{
1097	printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1098	walk_relocs(do_reloc_info);
1099}
1100
1101#if ELF_BITS == 64
1102# define process process_64
1103#else
1104# define process process_32
1105#endif
1106
1107void process(FILE *fp, int use_real_mode, int as_text,
1108	     int show_absolute_syms, int show_absolute_relocs,
1109	     int show_reloc_info)
1110{
1111	regex_init(use_real_mode);
1112	read_ehdr(fp);
1113	read_shdrs(fp);
1114	read_strtabs(fp);
1115	read_symtabs(fp);
1116	read_relocs(fp);
1117	if (ELF_BITS == 64)
1118		percpu_init();
1119	if (show_absolute_syms) {
1120		print_absolute_symbols();
1121		return;
1122	}
1123	if (show_absolute_relocs) {
1124		print_absolute_relocs();
1125		return;
1126	}
1127	if (show_reloc_info) {
1128		print_reloc_info();
1129		return;
1130	}
1131	emit_relocs(as_text, use_real_mode);
1132}