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;
  17static unsigned int	shsymtabndx;
  18static unsigned int	shxsymtabndx;
  19
  20static int sym_index(Elf_Sym *sym);
  21
  22struct relocs {
  23	uint32_t	*offset;
  24	unsigned long	count;
  25	unsigned long	size;
  26};
  27
  28static struct relocs relocs16;
  29static struct relocs relocs32;
  30#if ELF_BITS == 64
  31static struct relocs relocs32neg;
  32static struct relocs relocs64;
  33#define FMT PRIu64
  34#else
  35#define FMT PRIu32
  36#endif
  37
  38struct section {
  39	Elf_Shdr       shdr;
  40	struct section *link;
  41	Elf_Sym        *symtab;
  42	Elf32_Word     *xsymtab;
  43	Elf_Rel        *reltab;
  44	char           *strtab;
  45};
  46static struct section *secs;
  47
  48static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  49/*
  50 * Following symbols have been audited. There values are constant and do
  51 * not change if bzImage is loaded at a different physical address than
  52 * the address for which it has been compiled. Don't warn user about
  53 * absolute relocations present w.r.t these symbols.
  54 */
  55	[S_ABS] =
  56	"^(xen_irq_disable_direct_reloc$|"
  57	"xen_save_fl_direct_reloc$|"
  58	"VDSO|"
  59	"__kcfi_typeid_|"
  60	"__crc_)",
  61
  62/*
  63 * These symbols are known to be relative, even if the linker marks them
  64 * as absolute (typically defined outside any section in the linker script.)
  65 */
  66	[S_REL] =
  67	"^(__init_(begin|end)|"
  68	"__x86_cpu_dev_(start|end)|"
  69	"__alt_instructions(_end)?|"
  70	"(__iommu_table|__apicdrivers|__smp_locks)(_end)?|"
  71	"__(start|end)_pci_.*|"
  72#if CONFIG_FW_LOADER
  73	"__(start|end)_builtin_fw|"
  74#endif
  75	"__(start|stop)___ksymtab(_gpl)?|"
  76	"__(start|stop)___kcrctab(_gpl)?|"
  77	"__(start|stop)___param|"
  78	"__(start|stop)___modver|"
  79	"__(start|stop)___bug_table|"
  80	"__tracedata_(start|end)|"
  81	"__(start|stop)_notes|"
  82	"__end_rodata|"
  83	"__end_rodata_aligned|"
  84	"__initramfs_start|"
  85	"(jiffies|jiffies_64)|"
  86#if ELF_BITS == 64
  87	"__per_cpu_load|"
  88	"init_per_cpu__.*|"
  89	"__end_rodata_hpage_align|"
  90#endif
  91	"__vvar_page|"
  92	"_end)$"
  93};
  94
  95
  96static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  97/*
  98 * These symbols are known to be relative, even if the linker marks them
  99 * as absolute (typically defined outside any section in the linker script.)
 100 */
 101	[S_REL] =
 102	"^pa_",
 103
 104/*
 105 * These are 16-bit segment symbols when compiling 16-bit code.
 106 */
 107	[S_SEG] =
 108	"^real_mode_seg$",
 109
 110/*
 111 * These are offsets belonging to segments, as opposed to linear addresses,
 112 * when compiling 16-bit code.
 113 */
 114	[S_LIN] =
 115	"^pa_",
 116};
 117
 118static const char * const *sym_regex;
 119
 120static regex_t sym_regex_c[S_NSYMTYPES];
 121static int is_reloc(enum symtype type, const char *sym_name)
 122{
 123	return sym_regex[type] &&
 124		!regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
 125}
 126
 127static void regex_init(int use_real_mode)
 128{
 129        char errbuf[128];
 130        int err;
 131	int i;
 132
 133	if (use_real_mode)
 134		sym_regex = sym_regex_realmode;
 135	else
 136		sym_regex = sym_regex_kernel;
 137
 138	for (i = 0; i < S_NSYMTYPES; i++) {
 139		if (!sym_regex[i])
 140			continue;
 141
 142		err = regcomp(&sym_regex_c[i], sym_regex[i],
 143			      REG_EXTENDED|REG_NOSUB);
 144
 145		if (err) {
 146			regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf));
 147			die("%s", errbuf);
 148		}
 149        }
 150}
 151
 152static const char *sym_type(unsigned type)
 153{
 154	static const char *type_name[] = {
 155#define SYM_TYPE(X) [X] = #X
 156		SYM_TYPE(STT_NOTYPE),
 157		SYM_TYPE(STT_OBJECT),
 158		SYM_TYPE(STT_FUNC),
 159		SYM_TYPE(STT_SECTION),
 160		SYM_TYPE(STT_FILE),
 161		SYM_TYPE(STT_COMMON),
 162		SYM_TYPE(STT_TLS),
 163#undef SYM_TYPE
 164	};
 165	const char *name = "unknown sym type name";
 166	if (type < ARRAY_SIZE(type_name)) {
 167		name = type_name[type];
 168	}
 169	return name;
 170}
 171
 172static const char *sym_bind(unsigned bind)
 173{
 174	static const char *bind_name[] = {
 175#define SYM_BIND(X) [X] = #X
 176		SYM_BIND(STB_LOCAL),
 177		SYM_BIND(STB_GLOBAL),
 178		SYM_BIND(STB_WEAK),
 179#undef SYM_BIND
 180	};
 181	const char *name = "unknown sym bind name";
 182	if (bind < ARRAY_SIZE(bind_name)) {
 183		name = bind_name[bind];
 184	}
 185	return name;
 186}
 187
 188static const char *sym_visibility(unsigned visibility)
 189{
 190	static const char *visibility_name[] = {
 191#define SYM_VISIBILITY(X) [X] = #X
 192		SYM_VISIBILITY(STV_DEFAULT),
 193		SYM_VISIBILITY(STV_INTERNAL),
 194		SYM_VISIBILITY(STV_HIDDEN),
 195		SYM_VISIBILITY(STV_PROTECTED),
 196#undef SYM_VISIBILITY
 197	};
 198	const char *name = "unknown sym visibility name";
 199	if (visibility < ARRAY_SIZE(visibility_name)) {
 200		name = visibility_name[visibility];
 201	}
 202	return name;
 203}
 204
 205static const char *rel_type(unsigned type)
 206{
 207	static const char *type_name[] = {
 208#define REL_TYPE(X) [X] = #X
 209#if ELF_BITS == 64
 210		REL_TYPE(R_X86_64_NONE),
 211		REL_TYPE(R_X86_64_64),
 212		REL_TYPE(R_X86_64_PC64),
 213		REL_TYPE(R_X86_64_PC32),
 214		REL_TYPE(R_X86_64_GOT32),
 215		REL_TYPE(R_X86_64_PLT32),
 216		REL_TYPE(R_X86_64_COPY),
 217		REL_TYPE(R_X86_64_GLOB_DAT),
 218		REL_TYPE(R_X86_64_JUMP_SLOT),
 219		REL_TYPE(R_X86_64_RELATIVE),
 220		REL_TYPE(R_X86_64_GOTPCREL),
 221		REL_TYPE(R_X86_64_32),
 222		REL_TYPE(R_X86_64_32S),
 223		REL_TYPE(R_X86_64_16),
 224		REL_TYPE(R_X86_64_PC16),
 225		REL_TYPE(R_X86_64_8),
 226		REL_TYPE(R_X86_64_PC8),
 227#else
 228		REL_TYPE(R_386_NONE),
 229		REL_TYPE(R_386_32),
 230		REL_TYPE(R_386_PC32),
 231		REL_TYPE(R_386_GOT32),
 232		REL_TYPE(R_386_PLT32),
 233		REL_TYPE(R_386_COPY),
 234		REL_TYPE(R_386_GLOB_DAT),
 235		REL_TYPE(R_386_JMP_SLOT),
 236		REL_TYPE(R_386_RELATIVE),
 237		REL_TYPE(R_386_GOTOFF),
 238		REL_TYPE(R_386_GOTPC),
 239		REL_TYPE(R_386_8),
 240		REL_TYPE(R_386_PC8),
 241		REL_TYPE(R_386_16),
 242		REL_TYPE(R_386_PC16),
 243#endif
 244#undef REL_TYPE
 245	};
 246	const char *name = "unknown type rel type name";
 247	if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 248		name = type_name[type];
 249	}
 250	return name;
 251}
 252
 253static const char *sec_name(unsigned shndx)
 254{
 255	const char *sec_strtab;
 256	const char *name;
 257	sec_strtab = secs[shstrndx].strtab;
 258	name = "<noname>";
 259	if (shndx < shnum) {
 260		name = sec_strtab + secs[shndx].shdr.sh_name;
 261	}
 262	else if (shndx == SHN_ABS) {
 263		name = "ABSOLUTE";
 264	}
 265	else if (shndx == SHN_COMMON) {
 266		name = "COMMON";
 267	}
 268	return name;
 269}
 270
 271static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
 272{
 273	const char *name;
 274	name = "<noname>";
 275	if (sym->st_name) {
 276		name = sym_strtab + sym->st_name;
 277	}
 278	else {
 279		name = sec_name(sym_index(sym));
 280	}
 281	return name;
 282}
 283
 284static Elf_Sym *sym_lookup(const char *symname)
 285{
 286	int i;
 287	for (i = 0; i < shnum; i++) {
 288		struct section *sec = &secs[i];
 289		long nsyms;
 290		char *strtab;
 291		Elf_Sym *symtab;
 292		Elf_Sym *sym;
 293
 294		if (sec->shdr.sh_type != SHT_SYMTAB)
 295			continue;
 296
 297		nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
 298		symtab = sec->symtab;
 299		strtab = sec->link->strtab;
 300
 301		for (sym = symtab; --nsyms >= 0; sym++) {
 302			if (!sym->st_name)
 303				continue;
 304			if (strcmp(symname, strtab + sym->st_name) == 0)
 305				return sym;
 306		}
 307	}
 308	return 0;
 309}
 310
 311#if BYTE_ORDER == LITTLE_ENDIAN
 312#define le16_to_cpu(val) (val)
 313#define le32_to_cpu(val) (val)
 314#define le64_to_cpu(val) (val)
 315#endif
 316#if BYTE_ORDER == BIG_ENDIAN
 317#define le16_to_cpu(val) bswap_16(val)
 318#define le32_to_cpu(val) bswap_32(val)
 319#define le64_to_cpu(val) bswap_64(val)
 320#endif
 321
 322static uint16_t elf16_to_cpu(uint16_t val)
 323{
 324	return le16_to_cpu(val);
 325}
 326
 327static uint32_t elf32_to_cpu(uint32_t val)
 328{
 329	return le32_to_cpu(val);
 330}
 331
 332#define elf_half_to_cpu(x)	elf16_to_cpu(x)
 333#define elf_word_to_cpu(x)	elf32_to_cpu(x)
 334
 335#if ELF_BITS == 64
 336static uint64_t elf64_to_cpu(uint64_t val)
 337{
 338        return le64_to_cpu(val);
 339}
 340#define elf_addr_to_cpu(x)	elf64_to_cpu(x)
 341#define elf_off_to_cpu(x)	elf64_to_cpu(x)
 342#define elf_xword_to_cpu(x)	elf64_to_cpu(x)
 343#else
 344#define elf_addr_to_cpu(x)	elf32_to_cpu(x)
 345#define elf_off_to_cpu(x)	elf32_to_cpu(x)
 346#define elf_xword_to_cpu(x)	elf32_to_cpu(x)
 347#endif
 348
 349static int sym_index(Elf_Sym *sym)
 350{
 351	Elf_Sym *symtab = secs[shsymtabndx].symtab;
 352	Elf32_Word *xsymtab = secs[shxsymtabndx].xsymtab;
 353	unsigned long offset;
 354	int index;
 355
 356	if (sym->st_shndx != SHN_XINDEX)
 357		return sym->st_shndx;
 358
 359	/* calculate offset of sym from head of table. */
 360	offset = (unsigned long)sym - (unsigned long)symtab;
 361	index = offset / sizeof(*sym);
 362
 363	return elf32_to_cpu(xsymtab[index]);
 364}
 365
 366static void read_ehdr(FILE *fp)
 367{
 368	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 369		die("Cannot read ELF header: %s\n",
 370			strerror(errno));
 371	}
 372	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 373		die("No ELF magic\n");
 374	}
 375	if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
 376		die("Not a %d bit executable\n", ELF_BITS);
 377	}
 378	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 379		die("Not a LSB ELF executable\n");
 380	}
 381	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 382		die("Unknown ELF version\n");
 383	}
 384	/* Convert the fields to native endian */
 385	ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
 386	ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
 387	ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
 388	ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
 389	ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
 390	ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
 391	ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
 392	ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
 393	ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
 394	ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
 395	ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
 396	ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
 397	ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);
 398
 399	shnum = ehdr.e_shnum;
 400	shstrndx = ehdr.e_shstrndx;
 401
 402	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
 403		die("Unsupported ELF header type\n");
 404	if (ehdr.e_machine != ELF_MACHINE)
 405		die("Not for %s\n", ELF_MACHINE_NAME);
 406	if (ehdr.e_version != EV_CURRENT)
 407		die("Unknown ELF version\n");
 408	if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
 409		die("Bad ELF header size\n");
 410	if (ehdr.e_phentsize != sizeof(Elf_Phdr))
 411		die("Bad program header entry\n");
 412	if (ehdr.e_shentsize != sizeof(Elf_Shdr))
 413		die("Bad section header entry\n");
 414
 415
 416	if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
 417		Elf_Shdr shdr;
 418
 419		if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
 420			die("Seek to %" FMT " failed: %s\n", ehdr.e_shoff, strerror(errno));
 421
 422		if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 423			die("Cannot read initial ELF section header: %s\n", strerror(errno));
 424
 425		if (shnum == SHN_UNDEF)
 426			shnum = elf_xword_to_cpu(shdr.sh_size);
 427
 428		if (shstrndx == SHN_XINDEX)
 429			shstrndx = elf_word_to_cpu(shdr.sh_link);
 430	}
 431
 432	if (shstrndx >= shnum)
 433		die("String table index out of bounds\n");
 434}
 435
 436static void read_shdrs(FILE *fp)
 437{
 438	int i;
 439	Elf_Shdr shdr;
 440
 441	secs = calloc(shnum, sizeof(struct section));
 442	if (!secs) {
 443		die("Unable to allocate %ld section headers\n",
 444		    shnum);
 445	}
 446	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 447		die("Seek to %" FMT " failed: %s\n",
 448		    ehdr.e_shoff, strerror(errno));
 449	}
 450	for (i = 0; i < shnum; i++) {
 451		struct section *sec = &secs[i];
 452		if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 453			die("Cannot read ELF section headers %d/%ld: %s\n",
 454			    i, shnum, strerror(errno));
 455		sec->shdr.sh_name      = elf_word_to_cpu(shdr.sh_name);
 456		sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
 457		sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
 458		sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
 459		sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
 460		sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
 461		sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
 462		sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
 463		sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
 464		sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
 465		if (sec->shdr.sh_link < shnum)
 466			sec->link = &secs[sec->shdr.sh_link];
 467	}
 468
 469}
 470
 471static void read_strtabs(FILE *fp)
 472{
 473	int i;
 474	for (i = 0; i < shnum; i++) {
 475		struct section *sec = &secs[i];
 476		if (sec->shdr.sh_type != SHT_STRTAB) {
 477			continue;
 478		}
 479		sec->strtab = malloc(sec->shdr.sh_size);
 480		if (!sec->strtab) {
 481			die("malloc of %" FMT " bytes for strtab failed\n",
 482			    sec->shdr.sh_size);
 483		}
 484		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 485			die("Seek to %" FMT " failed: %s\n",
 486			    sec->shdr.sh_offset, strerror(errno));
 487		}
 488		if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 489		    != sec->shdr.sh_size) {
 490			die("Cannot read symbol table: %s\n",
 491				strerror(errno));
 492		}
 493	}
 494}
 495
 496static void read_symtabs(FILE *fp)
 497{
 498	int i,j;
 499
 500	for (i = 0; i < shnum; i++) {
 501		struct section *sec = &secs[i];
 502		int num_syms;
 503
 504		switch (sec->shdr.sh_type) {
 505		case SHT_SYMTAB_SHNDX:
 506			sec->xsymtab = malloc(sec->shdr.sh_size);
 507			if (!sec->xsymtab) {
 508				die("malloc of %" FMT " bytes for xsymtab failed\n",
 509				    sec->shdr.sh_size);
 510			}
 511			if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 512				die("Seek to %" FMT " failed: %s\n",
 513				    sec->shdr.sh_offset, strerror(errno));
 514			}
 515			if (fread(sec->xsymtab, 1, sec->shdr.sh_size, fp)
 516			    != sec->shdr.sh_size) {
 517				die("Cannot read extended symbol table: %s\n",
 518				    strerror(errno));
 519			}
 520			shxsymtabndx = i;
 521			continue;
 522
 523		case SHT_SYMTAB:
 524			num_syms = sec->shdr.sh_size / sizeof(Elf_Sym);
 525
 526			sec->symtab = malloc(sec->shdr.sh_size);
 527			if (!sec->symtab) {
 528				die("malloc of %" FMT " bytes for symtab failed\n",
 529				    sec->shdr.sh_size);
 530			}
 531			if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 532				die("Seek to %" FMT " failed: %s\n",
 533				    sec->shdr.sh_offset, strerror(errno));
 534			}
 535			if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 536			    != sec->shdr.sh_size) {
 537				die("Cannot read symbol table: %s\n",
 538				    strerror(errno));
 539			}
 540			for (j = 0; j < num_syms; j++) {
 541				Elf_Sym *sym = &sec->symtab[j];
 542
 543				sym->st_name  = elf_word_to_cpu(sym->st_name);
 544				sym->st_value = elf_addr_to_cpu(sym->st_value);
 545				sym->st_size  = elf_xword_to_cpu(sym->st_size);
 546				sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
 547			}
 548			shsymtabndx = i;
 549			continue;
 550
 551		default:
 552			continue;
 553		}
 554	}
 555}
 556
 557
 558static void read_relocs(FILE *fp)
 559{
 560	int i,j;
 561	for (i = 0; i < shnum; i++) {
 562		struct section *sec = &secs[i];
 563		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 564			continue;
 565		}
 566		sec->reltab = malloc(sec->shdr.sh_size);
 567		if (!sec->reltab) {
 568			die("malloc of %" FMT " bytes for relocs failed\n",
 569			    sec->shdr.sh_size);
 570		}
 571		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 572			die("Seek to %" FMT " failed: %s\n",
 573			    sec->shdr.sh_offset, strerror(errno));
 574		}
 575		if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 576		    != sec->shdr.sh_size) {
 577			die("Cannot read symbol table: %s\n",
 578				strerror(errno));
 579		}
 580		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 581			Elf_Rel *rel = &sec->reltab[j];
 582			rel->r_offset = elf_addr_to_cpu(rel->r_offset);
 583			rel->r_info   = elf_xword_to_cpu(rel->r_info);
 584#if (SHT_REL_TYPE == SHT_RELA)
 585			rel->r_addend = elf_xword_to_cpu(rel->r_addend);
 586#endif
 587		}
 588	}
 589}
 590
 591
 592static void print_absolute_symbols(void)
 593{
 594	int i;
 595	const char *format;
 596
 597	if (ELF_BITS == 64)
 598		format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
 599	else
 600		format = "%5d %08"PRIx32"  %5"PRId32" %10s %10s %12s %s\n";
 601
 602	printf("Absolute symbols\n");
 603	printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 604	for (i = 0; i < shnum; i++) {
 605		struct section *sec = &secs[i];
 606		char *sym_strtab;
 607		int j;
 608
 609		if (sec->shdr.sh_type != SHT_SYMTAB) {
 610			continue;
 611		}
 612		sym_strtab = sec->link->strtab;
 613		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
 614			Elf_Sym *sym;
 615			const char *name;
 616			sym = &sec->symtab[j];
 617			name = sym_name(sym_strtab, sym);
 618			if (sym->st_shndx != SHN_ABS) {
 619				continue;
 620			}
 621			printf(format,
 622				j, sym->st_value, sym->st_size,
 623				sym_type(ELF_ST_TYPE(sym->st_info)),
 624				sym_bind(ELF_ST_BIND(sym->st_info)),
 625				sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
 626				name);
 627		}
 628	}
 629	printf("\n");
 630}
 631
 632static void print_absolute_relocs(void)
 633{
 634	int i, printed = 0;
 635	const char *format;
 636
 637	if (ELF_BITS == 64)
 638		format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64"  %s\n";
 639	else
 640		format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32"  %s\n";
 641
 642	for (i = 0; i < shnum; i++) {
 643		struct section *sec = &secs[i];
 644		struct section *sec_applies, *sec_symtab;
 645		char *sym_strtab;
 646		Elf_Sym *sh_symtab;
 647		int j;
 648		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 649			continue;
 650		}
 651		sec_symtab  = sec->link;
 652		sec_applies = &secs[sec->shdr.sh_info];
 653		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 654			continue;
 655		}
 
 
 
 
 
 
 
 
 656		sh_symtab  = sec_symtab->symtab;
 657		sym_strtab = sec_symtab->link->strtab;
 658		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 659			Elf_Rel *rel;
 660			Elf_Sym *sym;
 661			const char *name;
 662			rel = &sec->reltab[j];
 663			sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 664			name = sym_name(sym_strtab, sym);
 665			if (sym->st_shndx != SHN_ABS) {
 666				continue;
 667			}
 668
 669			/* Absolute symbols are not relocated if bzImage is
 670			 * loaded at a non-compiled address. Display a warning
 671			 * to user at compile time about the absolute
 672			 * relocations present.
 673			 *
 674			 * User need to audit the code to make sure
 675			 * some symbols which should have been section
 676			 * relative have not become absolute because of some
 677			 * linker optimization or wrong programming usage.
 678			 *
 679			 * Before warning check if this absolute symbol
 680			 * relocation is harmless.
 681			 */
 682			if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 683				continue;
 684
 685			if (!printed) {
 686				printf("WARNING: Absolute relocations"
 687					" present\n");
 688				printf("Offset     Info     Type     Sym.Value "
 689					"Sym.Name\n");
 690				printed = 1;
 691			}
 692
 693			printf(format,
 694				rel->r_offset,
 695				rel->r_info,
 696				rel_type(ELF_R_TYPE(rel->r_info)),
 697				sym->st_value,
 698				name);
 699		}
 700	}
 701
 702	if (printed)
 703		printf("\n");
 704}
 705
 706static void add_reloc(struct relocs *r, uint32_t offset)
 707{
 708	if (r->count == r->size) {
 709		unsigned long newsize = r->size + 50000;
 710		void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
 711
 712		if (!mem)
 713			die("realloc of %ld entries for relocs failed\n",
 714                                newsize);
 715		r->offset = mem;
 716		r->size = newsize;
 717	}
 718	r->offset[r->count++] = offset;
 719}
 720
 721static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 722			Elf_Sym *sym, const char *symname))
 723{
 724	int i;
 725	/* Walk through the relocations */
 726	for (i = 0; i < shnum; i++) {
 727		char *sym_strtab;
 728		Elf_Sym *sh_symtab;
 729		struct section *sec_applies, *sec_symtab;
 730		int j;
 731		struct section *sec = &secs[i];
 732
 733		if (sec->shdr.sh_type != SHT_REL_TYPE) {
 734			continue;
 735		}
 736		sec_symtab  = sec->link;
 737		sec_applies = &secs[sec->shdr.sh_info];
 738		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 739			continue;
 740		}
 
 
 
 
 
 
 
 
 
 741		sh_symtab = sec_symtab->symtab;
 742		sym_strtab = sec_symtab->link->strtab;
 743		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 744			Elf_Rel *rel = &sec->reltab[j];
 745			Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 746			const char *symname = sym_name(sym_strtab, sym);
 747
 748			process(sec, rel, sym, symname);
 749		}
 750	}
 751}
 752
 753/*
 754 * The .data..percpu section is a special case for x86_64 SMP kernels.
 755 * It is used to initialize the actual per_cpu areas and to provide
 756 * definitions for the per_cpu variables that correspond to their offsets
 757 * within the percpu area. Since the values of all of the symbols need
 758 * to be offsets from the start of the per_cpu area the virtual address
 759 * (sh_addr) of .data..percpu is 0 in SMP kernels.
 760 *
 761 * This means that:
 762 *
 763 *	Relocations that reference symbols in the per_cpu area do not
 764 *	need further relocation (since the value is an offset relative
 765 *	to the start of the per_cpu area that does not change).
 766 *
 767 *	Relocations that apply to the per_cpu area need to have their
 768 *	offset adjusted by by the value of __per_cpu_load to make them
 769 *	point to the correct place in the loaded image (because the
 770 *	virtual address of .data..percpu is 0).
 771 *
 772 * For non SMP kernels .data..percpu is linked as part of the normal
 773 * kernel data and does not require special treatment.
 774 *
 775 */
 776static int per_cpu_shndx	= -1;
 777static Elf_Addr per_cpu_load_addr;
 778
 779static void percpu_init(void)
 780{
 781	int i;
 782	for (i = 0; i < shnum; i++) {
 783		ElfW(Sym) *sym;
 784		if (strcmp(sec_name(i), ".data..percpu"))
 785			continue;
 786
 787		if (secs[i].shdr.sh_addr != 0)	/* non SMP kernel */
 788			return;
 789
 790		sym = sym_lookup("__per_cpu_load");
 791		if (!sym)
 792			die("can't find __per_cpu_load\n");
 793
 794		per_cpu_shndx = i;
 795		per_cpu_load_addr = sym->st_value;
 796		return;
 797	}
 798}
 799
 800#if ELF_BITS == 64
 801
 802/*
 803 * Check to see if a symbol lies in the .data..percpu section.
 804 *
 805 * The linker incorrectly associates some symbols with the
 806 * .data..percpu section so we also need to check the symbol
 807 * name to make sure that we classify the symbol correctly.
 808 *
 809 * The GNU linker incorrectly associates:
 810 *	__init_begin
 811 *	__per_cpu_load
 812 *
 813 * The "gold" linker incorrectly associates:
 814 *	init_per_cpu__fixed_percpu_data
 815 *	init_per_cpu__gdt_page
 816 */
 817static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
 818{
 819	int shndx = sym_index(sym);
 820
 821	return (shndx == per_cpu_shndx) &&
 822		strcmp(symname, "__init_begin") &&
 823		strcmp(symname, "__per_cpu_load") &&
 824		strncmp(symname, "init_per_cpu_", 13);
 825}
 826
 827
 828static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 829		      const char *symname)
 830{
 831	unsigned r_type = ELF64_R_TYPE(rel->r_info);
 832	ElfW(Addr) offset = rel->r_offset;
 833	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 834
 835	if (sym->st_shndx == SHN_UNDEF)
 836		return 0;
 837
 838	/*
 839	 * Adjust the offset if this reloc applies to the percpu section.
 840	 */
 841	if (sec->shdr.sh_info == per_cpu_shndx)
 842		offset += per_cpu_load_addr;
 843
 844	switch (r_type) {
 845	case R_X86_64_NONE:
 846		/* NONE can be ignored. */
 847		break;
 848
 849	case R_X86_64_PC32:
 850	case R_X86_64_PLT32:
 851		/*
 852		 * PC relative relocations don't need to be adjusted unless
 853		 * referencing a percpu symbol.
 854		 *
 855		 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
 856		 */
 857		if (is_percpu_sym(sym, symname))
 858			add_reloc(&relocs32neg, offset);
 859		break;
 860
 861	case R_X86_64_PC64:
 862		/*
 863		 * Only used by jump labels
 864		 */
 865		if (is_percpu_sym(sym, symname))
 866			die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
 867			    symname);
 868		break;
 869
 870	case R_X86_64_32:
 871	case R_X86_64_32S:
 872	case R_X86_64_64:
 873		/*
 874		 * References to the percpu area don't need to be adjusted.
 875		 */
 876		if (is_percpu_sym(sym, symname))
 877			break;
 878
 879		if (shn_abs) {
 880			/*
 881			 * Whitelisted absolute symbols do not require
 882			 * relocation.
 883			 */
 884			if (is_reloc(S_ABS, symname))
 885				break;
 886
 887			die("Invalid absolute %s relocation: %s\n",
 888			    rel_type(r_type), symname);
 889			break;
 890		}
 891
 892		/*
 893		 * Relocation offsets for 64 bit kernels are output
 894		 * as 32 bits and sign extended back to 64 bits when
 895		 * the relocations are processed.
 896		 * Make sure that the offset will fit.
 897		 */
 898		if ((int32_t)offset != (int64_t)offset)
 899			die("Relocation offset doesn't fit in 32 bits\n");
 900
 901		if (r_type == R_X86_64_64)
 902			add_reloc(&relocs64, offset);
 903		else
 904			add_reloc(&relocs32, offset);
 905		break;
 906
 907	default:
 908		die("Unsupported relocation type: %s (%d)\n",
 909		    rel_type(r_type), r_type);
 910		break;
 911	}
 912
 913	return 0;
 914}
 915
 916#else
 917
 918static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 919		      const char *symname)
 920{
 921	unsigned r_type = ELF32_R_TYPE(rel->r_info);
 922	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 923
 924	switch (r_type) {
 925	case R_386_NONE:
 926	case R_386_PC32:
 927	case R_386_PC16:
 928	case R_386_PC8:
 929	case R_386_PLT32:
 930		/*
 931		 * NONE can be ignored and PC relative relocations don't need
 932		 * to be adjusted. Because sym must be defined, R_386_PLT32 can
 933		 * be treated the same way as R_386_PC32.
 934		 */
 935		break;
 936
 937	case R_386_32:
 938		if (shn_abs) {
 939			/*
 940			 * Whitelisted absolute symbols do not require
 941			 * relocation.
 942			 */
 943			if (is_reloc(S_ABS, symname))
 944				break;
 945
 946			die("Invalid absolute %s relocation: %s\n",
 947			    rel_type(r_type), symname);
 948			break;
 949		}
 950
 951		add_reloc(&relocs32, rel->r_offset);
 952		break;
 953
 954	default:
 955		die("Unsupported relocation type: %s (%d)\n",
 956		    rel_type(r_type), r_type);
 957		break;
 958	}
 959
 960	return 0;
 961}
 962
 963static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 964			 const char *symname)
 965{
 966	unsigned r_type = ELF32_R_TYPE(rel->r_info);
 967	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 968
 969	switch (r_type) {
 970	case R_386_NONE:
 971	case R_386_PC32:
 972	case R_386_PC16:
 973	case R_386_PC8:
 974	case R_386_PLT32:
 975		/*
 976		 * NONE can be ignored and PC relative relocations don't need
 977		 * to be adjusted. Because sym must be defined, R_386_PLT32 can
 978		 * be treated the same way as R_386_PC32.
 979		 */
 980		break;
 981
 982	case R_386_16:
 983		if (shn_abs) {
 984			/*
 985			 * Whitelisted absolute symbols do not require
 986			 * relocation.
 987			 */
 988			if (is_reloc(S_ABS, symname))
 989				break;
 990
 991			if (is_reloc(S_SEG, symname)) {
 992				add_reloc(&relocs16, rel->r_offset);
 993				break;
 994			}
 995		} else {
 996			if (!is_reloc(S_LIN, symname))
 997				break;
 998		}
 999		die("Invalid %s %s relocation: %s\n",
1000		    shn_abs ? "absolute" : "relative",
1001		    rel_type(r_type), symname);
1002		break;
1003
1004	case R_386_32:
1005		if (shn_abs) {
1006			/*
1007			 * Whitelisted absolute symbols do not require
1008			 * relocation.
1009			 */
1010			if (is_reloc(S_ABS, symname))
1011				break;
1012
1013			if (is_reloc(S_REL, symname)) {
1014				add_reloc(&relocs32, rel->r_offset);
1015				break;
1016			}
1017		} else {
1018			if (is_reloc(S_LIN, symname))
1019				add_reloc(&relocs32, rel->r_offset);
1020			break;
1021		}
1022		die("Invalid %s %s relocation: %s\n",
1023		    shn_abs ? "absolute" : "relative",
1024		    rel_type(r_type), symname);
1025		break;
1026
1027	default:
1028		die("Unsupported relocation type: %s (%d)\n",
1029		    rel_type(r_type), r_type);
1030		break;
1031	}
1032
1033	return 0;
1034}
1035
1036#endif
1037
1038static int cmp_relocs(const void *va, const void *vb)
1039{
1040	const uint32_t *a, *b;
1041	a = va; b = vb;
1042	return (*a == *b)? 0 : (*a > *b)? 1 : -1;
1043}
1044
1045static void sort_relocs(struct relocs *r)
1046{
1047	qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
1048}
1049
1050static int write32(uint32_t v, FILE *f)
1051{
1052	unsigned char buf[4];
1053
1054	put_unaligned_le32(v, buf);
1055	return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
1056}
1057
1058static int write32_as_text(uint32_t v, FILE *f)
1059{
1060	return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
1061}
1062
1063static void emit_relocs(int as_text, int use_real_mode)
1064{
1065	int i;
1066	int (*write_reloc)(uint32_t, FILE *) = write32;
1067	int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
1068			const char *symname);
1069
1070#if ELF_BITS == 64
1071	if (!use_real_mode)
1072		do_reloc = do_reloc64;
1073	else
1074		die("--realmode not valid for a 64-bit ELF file");
1075#else
1076	if (!use_real_mode)
1077		do_reloc = do_reloc32;
1078	else
1079		do_reloc = do_reloc_real;
1080#endif
1081
1082	/* Collect up the relocations */
1083	walk_relocs(do_reloc);
1084
1085	if (relocs16.count && !use_real_mode)
1086		die("Segment relocations found but --realmode not specified\n");
1087
1088	/* Order the relocations for more efficient processing */
1089	sort_relocs(&relocs32);
1090#if ELF_BITS == 64
1091	sort_relocs(&relocs32neg);
1092	sort_relocs(&relocs64);
1093#else
1094	sort_relocs(&relocs16);
1095#endif
1096
1097	/* Print the relocations */
1098	if (as_text) {
1099		/* Print the relocations in a form suitable that
1100		 * gas will like.
1101		 */
1102		printf(".section \".data.reloc\",\"a\"\n");
1103		printf(".balign 4\n");
1104		write_reloc = write32_as_text;
1105	}
1106
1107	if (use_real_mode) {
1108		write_reloc(relocs16.count, stdout);
1109		for (i = 0; i < relocs16.count; i++)
1110			write_reloc(relocs16.offset[i], stdout);
1111
1112		write_reloc(relocs32.count, stdout);
1113		for (i = 0; i < relocs32.count; i++)
1114			write_reloc(relocs32.offset[i], stdout);
1115	} else {
1116#if ELF_BITS == 64
1117		/* Print a stop */
1118		write_reloc(0, stdout);
1119
1120		/* Now print each relocation */
1121		for (i = 0; i < relocs64.count; i++)
1122			write_reloc(relocs64.offset[i], stdout);
1123
1124		/* Print a stop */
1125		write_reloc(0, stdout);
1126
1127		/* Now print each inverse 32-bit relocation */
1128		for (i = 0; i < relocs32neg.count; i++)
1129			write_reloc(relocs32neg.offset[i], stdout);
1130#endif
1131
1132		/* Print a stop */
1133		write_reloc(0, stdout);
1134
1135		/* Now print each relocation */
1136		for (i = 0; i < relocs32.count; i++)
1137			write_reloc(relocs32.offset[i], stdout);
1138	}
1139}
1140
1141/*
1142 * As an aid to debugging problems with different linkers
1143 * print summary information about the relocs.
1144 * Since different linkers tend to emit the sections in
1145 * different orders we use the section names in the output.
1146 */
1147static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1148				const char *symname)
1149{
1150	printf("%s\t%s\t%s\t%s\n",
1151		sec_name(sec->shdr.sh_info),
1152		rel_type(ELF_R_TYPE(rel->r_info)),
1153		symname,
1154		sec_name(sym_index(sym)));
1155	return 0;
1156}
1157
1158static void print_reloc_info(void)
1159{
1160	printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1161	walk_relocs(do_reloc_info);
1162}
1163
1164#if ELF_BITS == 64
1165# define process process_64
1166#else
1167# define process process_32
1168#endif
1169
1170void process(FILE *fp, int use_real_mode, int as_text,
1171	     int show_absolute_syms, int show_absolute_relocs,
1172	     int show_reloc_info)
1173{
1174	regex_init(use_real_mode);
1175	read_ehdr(fp);
1176	read_shdrs(fp);
1177	read_strtabs(fp);
1178	read_symtabs(fp);
1179	read_relocs(fp);
1180	if (ELF_BITS == 64)
1181		percpu_init();
1182	if (show_absolute_syms) {
1183		print_absolute_symbols();
1184		return;
1185	}
1186	if (show_absolute_relocs) {
1187		print_absolute_relocs();
1188		return;
1189	}
1190	if (show_reloc_info) {
1191		print_reloc_info();
1192		return;
1193	}
1194	emit_relocs(as_text, use_real_mode);
1195}