xref: /openbmc/linux/arch/x86/tools/relocs.c (revision c54a354c)
1 #include <stdio.h>
2 #include <stdarg.h>
3 #include <stdlib.h>
4 #include <stdint.h>
5 #include <string.h>
6 #include <errno.h>
7 #include <unistd.h>
8 #include <elf.h>
9 #include <byteswap.h>
10 #define USE_BSD
11 #include <endian.h>
12 #include <regex.h>
13 #include <tools/le_byteshift.h>
14 
15 static void die(char *fmt, ...);
16 
17 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
18 static Elf32_Ehdr ehdr;
19 static unsigned long reloc_count, reloc_idx;
20 static unsigned long *relocs;
21 static unsigned long reloc16_count, reloc16_idx;
22 static unsigned long *relocs16;
23 
24 struct section {
25 	Elf32_Shdr     shdr;
26 	struct section *link;
27 	Elf32_Sym      *symtab;
28 	Elf32_Rel      *reltab;
29 	char           *strtab;
30 };
31 static struct section *secs;
32 
33 enum symtype {
34 	S_ABS,
35 	S_REL,
36 	S_SEG,
37 	S_LIN,
38 	S_NSYMTYPES
39 };
40 
41 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
42 /*
43  * Following symbols have been audited. There values are constant and do
44  * not change if bzImage is loaded at a different physical address than
45  * the address for which it has been compiled. Don't warn user about
46  * absolute relocations present w.r.t these symbols.
47  */
48 	[S_ABS] =
49 	"^(xen_irq_disable_direct_reloc$|"
50 	"xen_save_fl_direct_reloc$|"
51 	"VDSO|"
52 	"__crc_)",
53 
54 /*
55  * These symbols are known to be relative, even if the linker marks them
56  * as absolute (typically defined outside any section in the linker script.)
57  */
58 	[S_REL] =
59 	"^(__init_(begin|end)|"
60 	"__x86_cpu_dev_(start|end)|"
61 	"(__parainstructions|__alt_instructions)(|_end)|"
62 	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
63 	"_end)$"
64 };
65 
66 
67 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
68 /*
69  * These symbols are known to be relative, even if the linker marks them
70  * as absolute (typically defined outside any section in the linker script.)
71  */
72 	[S_REL] =
73 	"^pa_",
74 
75 /*
76  * These are 16-bit segment symbols when compiling 16-bit code.
77  */
78 	[S_SEG] =
79 	"^real_mode_seg$",
80 
81 /*
82  * These are offsets belonging to segments, as opposed to linear addresses,
83  * when compiling 16-bit code.
84  */
85 	[S_LIN] =
86 	"^pa_",
87 };
88 
89 static const char * const *sym_regex;
90 
91 static regex_t sym_regex_c[S_NSYMTYPES];
92 static int is_reloc(enum symtype type, const char *sym_name)
93 {
94 	return sym_regex[type] &&
95 		!regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
96 }
97 
98 static void regex_init(int use_real_mode)
99 {
100         char errbuf[128];
101         int err;
102 	int i;
103 
104 	if (use_real_mode)
105 		sym_regex = sym_regex_realmode;
106 	else
107 		sym_regex = sym_regex_kernel;
108 
109 	for (i = 0; i < S_NSYMTYPES; i++) {
110 		if (!sym_regex[i])
111 			continue;
112 
113 		err = regcomp(&sym_regex_c[i], sym_regex[i],
114 			      REG_EXTENDED|REG_NOSUB);
115 
116 		if (err) {
117 			regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
118 			die("%s", errbuf);
119 		}
120         }
121 }
122 
123 static void die(char *fmt, ...)
124 {
125 	va_list ap;
126 	va_start(ap, fmt);
127 	vfprintf(stderr, fmt, ap);
128 	va_end(ap);
129 	exit(1);
130 }
131 
132 static const char *sym_type(unsigned type)
133 {
134 	static const char *type_name[] = {
135 #define SYM_TYPE(X) [X] = #X
136 		SYM_TYPE(STT_NOTYPE),
137 		SYM_TYPE(STT_OBJECT),
138 		SYM_TYPE(STT_FUNC),
139 		SYM_TYPE(STT_SECTION),
140 		SYM_TYPE(STT_FILE),
141 		SYM_TYPE(STT_COMMON),
142 		SYM_TYPE(STT_TLS),
143 #undef SYM_TYPE
144 	};
145 	const char *name = "unknown sym type name";
146 	if (type < ARRAY_SIZE(type_name)) {
147 		name = type_name[type];
148 	}
149 	return name;
150 }
151 
152 static const char *sym_bind(unsigned bind)
153 {
154 	static const char *bind_name[] = {
155 #define SYM_BIND(X) [X] = #X
156 		SYM_BIND(STB_LOCAL),
157 		SYM_BIND(STB_GLOBAL),
158 		SYM_BIND(STB_WEAK),
159 #undef SYM_BIND
160 	};
161 	const char *name = "unknown sym bind name";
162 	if (bind < ARRAY_SIZE(bind_name)) {
163 		name = bind_name[bind];
164 	}
165 	return name;
166 }
167 
168 static const char *sym_visibility(unsigned visibility)
169 {
170 	static const char *visibility_name[] = {
171 #define SYM_VISIBILITY(X) [X] = #X
172 		SYM_VISIBILITY(STV_DEFAULT),
173 		SYM_VISIBILITY(STV_INTERNAL),
174 		SYM_VISIBILITY(STV_HIDDEN),
175 		SYM_VISIBILITY(STV_PROTECTED),
176 #undef SYM_VISIBILITY
177 	};
178 	const char *name = "unknown sym visibility name";
179 	if (visibility < ARRAY_SIZE(visibility_name)) {
180 		name = visibility_name[visibility];
181 	}
182 	return name;
183 }
184 
185 static const char *rel_type(unsigned type)
186 {
187 	static const char *type_name[] = {
188 #define REL_TYPE(X) [X] = #X
189 		REL_TYPE(R_386_NONE),
190 		REL_TYPE(R_386_32),
191 		REL_TYPE(R_386_PC32),
192 		REL_TYPE(R_386_GOT32),
193 		REL_TYPE(R_386_PLT32),
194 		REL_TYPE(R_386_COPY),
195 		REL_TYPE(R_386_GLOB_DAT),
196 		REL_TYPE(R_386_JMP_SLOT),
197 		REL_TYPE(R_386_RELATIVE),
198 		REL_TYPE(R_386_GOTOFF),
199 		REL_TYPE(R_386_GOTPC),
200 		REL_TYPE(R_386_8),
201 		REL_TYPE(R_386_PC8),
202 		REL_TYPE(R_386_16),
203 		REL_TYPE(R_386_PC16),
204 #undef REL_TYPE
205 	};
206 	const char *name = "unknown type rel type name";
207 	if (type < ARRAY_SIZE(type_name) && type_name[type]) {
208 		name = type_name[type];
209 	}
210 	return name;
211 }
212 
213 static const char *sec_name(unsigned shndx)
214 {
215 	const char *sec_strtab;
216 	const char *name;
217 	sec_strtab = secs[ehdr.e_shstrndx].strtab;
218 	name = "<noname>";
219 	if (shndx < ehdr.e_shnum) {
220 		name = sec_strtab + secs[shndx].shdr.sh_name;
221 	}
222 	else if (shndx == SHN_ABS) {
223 		name = "ABSOLUTE";
224 	}
225 	else if (shndx == SHN_COMMON) {
226 		name = "COMMON";
227 	}
228 	return name;
229 }
230 
231 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
232 {
233 	const char *name;
234 	name = "<noname>";
235 	if (sym->st_name) {
236 		name = sym_strtab + sym->st_name;
237 	}
238 	else {
239 		name = sec_name(sym->st_shndx);
240 	}
241 	return name;
242 }
243 
244 
245 
246 #if BYTE_ORDER == LITTLE_ENDIAN
247 #define le16_to_cpu(val) (val)
248 #define le32_to_cpu(val) (val)
249 #endif
250 #if BYTE_ORDER == BIG_ENDIAN
251 #define le16_to_cpu(val) bswap_16(val)
252 #define le32_to_cpu(val) bswap_32(val)
253 #endif
254 
255 static uint16_t elf16_to_cpu(uint16_t val)
256 {
257 	return le16_to_cpu(val);
258 }
259 
260 static uint32_t elf32_to_cpu(uint32_t val)
261 {
262 	return le32_to_cpu(val);
263 }
264 
265 static void read_ehdr(FILE *fp)
266 {
267 	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
268 		die("Cannot read ELF header: %s\n",
269 			strerror(errno));
270 	}
271 	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
272 		die("No ELF magic\n");
273 	}
274 	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
275 		die("Not a 32 bit executable\n");
276 	}
277 	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
278 		die("Not a LSB ELF executable\n");
279 	}
280 	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
281 		die("Unknown ELF version\n");
282 	}
283 	/* Convert the fields to native endian */
284 	ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
285 	ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
286 	ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
287 	ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
288 	ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
289 	ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
290 	ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
291 	ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
292 	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
293 	ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
294 	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
295 	ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
296 	ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
297 
298 	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
299 		die("Unsupported ELF header type\n");
300 	}
301 	if (ehdr.e_machine != EM_386) {
302 		die("Not for x86\n");
303 	}
304 	if (ehdr.e_version != EV_CURRENT) {
305 		die("Unknown ELF version\n");
306 	}
307 	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
308 		die("Bad Elf header size\n");
309 	}
310 	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
311 		die("Bad program header entry\n");
312 	}
313 	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
314 		die("Bad section header entry\n");
315 	}
316 	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
317 		die("String table index out of bounds\n");
318 	}
319 }
320 
321 static void read_shdrs(FILE *fp)
322 {
323 	int i;
324 	Elf32_Shdr shdr;
325 
326 	secs = calloc(ehdr.e_shnum, sizeof(struct section));
327 	if (!secs) {
328 		die("Unable to allocate %d section headers\n",
329 		    ehdr.e_shnum);
330 	}
331 	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
332 		die("Seek to %d failed: %s\n",
333 			ehdr.e_shoff, strerror(errno));
334 	}
335 	for (i = 0; i < ehdr.e_shnum; i++) {
336 		struct section *sec = &secs[i];
337 		if (fread(&shdr, sizeof shdr, 1, fp) != 1)
338 			die("Cannot read ELF section headers %d/%d: %s\n",
339 			    i, ehdr.e_shnum, strerror(errno));
340 		sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
341 		sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
342 		sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
343 		sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
344 		sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
345 		sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
346 		sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
347 		sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
348 		sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
349 		sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
350 		if (sec->shdr.sh_link < ehdr.e_shnum)
351 			sec->link = &secs[sec->shdr.sh_link];
352 	}
353 
354 }
355 
356 static void read_strtabs(FILE *fp)
357 {
358 	int i;
359 	for (i = 0; i < ehdr.e_shnum; i++) {
360 		struct section *sec = &secs[i];
361 		if (sec->shdr.sh_type != SHT_STRTAB) {
362 			continue;
363 		}
364 		sec->strtab = malloc(sec->shdr.sh_size);
365 		if (!sec->strtab) {
366 			die("malloc of %d bytes for strtab failed\n",
367 				sec->shdr.sh_size);
368 		}
369 		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
370 			die("Seek to %d failed: %s\n",
371 				sec->shdr.sh_offset, strerror(errno));
372 		}
373 		if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
374 		    != sec->shdr.sh_size) {
375 			die("Cannot read symbol table: %s\n",
376 				strerror(errno));
377 		}
378 	}
379 }
380 
381 static void read_symtabs(FILE *fp)
382 {
383 	int i,j;
384 	for (i = 0; i < ehdr.e_shnum; i++) {
385 		struct section *sec = &secs[i];
386 		if (sec->shdr.sh_type != SHT_SYMTAB) {
387 			continue;
388 		}
389 		sec->symtab = malloc(sec->shdr.sh_size);
390 		if (!sec->symtab) {
391 			die("malloc of %d bytes for symtab failed\n",
392 				sec->shdr.sh_size);
393 		}
394 		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
395 			die("Seek to %d failed: %s\n",
396 				sec->shdr.sh_offset, strerror(errno));
397 		}
398 		if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
399 		    != sec->shdr.sh_size) {
400 			die("Cannot read symbol table: %s\n",
401 				strerror(errno));
402 		}
403 		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
404 			Elf32_Sym *sym = &sec->symtab[j];
405 			sym->st_name  = elf32_to_cpu(sym->st_name);
406 			sym->st_value = elf32_to_cpu(sym->st_value);
407 			sym->st_size  = elf32_to_cpu(sym->st_size);
408 			sym->st_shndx = elf16_to_cpu(sym->st_shndx);
409 		}
410 	}
411 }
412 
413 
414 static void read_relocs(FILE *fp)
415 {
416 	int i,j;
417 	for (i = 0; i < ehdr.e_shnum; i++) {
418 		struct section *sec = &secs[i];
419 		if (sec->shdr.sh_type != SHT_REL) {
420 			continue;
421 		}
422 		sec->reltab = malloc(sec->shdr.sh_size);
423 		if (!sec->reltab) {
424 			die("malloc of %d bytes for relocs failed\n",
425 				sec->shdr.sh_size);
426 		}
427 		if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
428 			die("Seek to %d failed: %s\n",
429 				sec->shdr.sh_offset, strerror(errno));
430 		}
431 		if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
432 		    != sec->shdr.sh_size) {
433 			die("Cannot read symbol table: %s\n",
434 				strerror(errno));
435 		}
436 		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
437 			Elf32_Rel *rel = &sec->reltab[j];
438 			rel->r_offset = elf32_to_cpu(rel->r_offset);
439 			rel->r_info   = elf32_to_cpu(rel->r_info);
440 		}
441 	}
442 }
443 
444 
445 static void print_absolute_symbols(void)
446 {
447 	int i;
448 	printf("Absolute symbols\n");
449 	printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
450 	for (i = 0; i < ehdr.e_shnum; i++) {
451 		struct section *sec = &secs[i];
452 		char *sym_strtab;
453 		int j;
454 
455 		if (sec->shdr.sh_type != SHT_SYMTAB) {
456 			continue;
457 		}
458 		sym_strtab = sec->link->strtab;
459 		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
460 			Elf32_Sym *sym;
461 			const char *name;
462 			sym = &sec->symtab[j];
463 			name = sym_name(sym_strtab, sym);
464 			if (sym->st_shndx != SHN_ABS) {
465 				continue;
466 			}
467 			printf("%5d %08x %5d %10s %10s %12s %s\n",
468 				j, sym->st_value, sym->st_size,
469 				sym_type(ELF32_ST_TYPE(sym->st_info)),
470 				sym_bind(ELF32_ST_BIND(sym->st_info)),
471 				sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
472 				name);
473 		}
474 	}
475 	printf("\n");
476 }
477 
478 static void print_absolute_relocs(void)
479 {
480 	int i, printed = 0;
481 
482 	for (i = 0; i < ehdr.e_shnum; i++) {
483 		struct section *sec = &secs[i];
484 		struct section *sec_applies, *sec_symtab;
485 		char *sym_strtab;
486 		Elf32_Sym *sh_symtab;
487 		int j;
488 		if (sec->shdr.sh_type != SHT_REL) {
489 			continue;
490 		}
491 		sec_symtab  = sec->link;
492 		sec_applies = &secs[sec->shdr.sh_info];
493 		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
494 			continue;
495 		}
496 		sh_symtab  = sec_symtab->symtab;
497 		sym_strtab = sec_symtab->link->strtab;
498 		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
499 			Elf32_Rel *rel;
500 			Elf32_Sym *sym;
501 			const char *name;
502 			rel = &sec->reltab[j];
503 			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
504 			name = sym_name(sym_strtab, sym);
505 			if (sym->st_shndx != SHN_ABS) {
506 				continue;
507 			}
508 
509 			/* Absolute symbols are not relocated if bzImage is
510 			 * loaded at a non-compiled address. Display a warning
511 			 * to user at compile time about the absolute
512 			 * relocations present.
513 			 *
514 			 * User need to audit the code to make sure
515 			 * some symbols which should have been section
516 			 * relative have not become absolute because of some
517 			 * linker optimization or wrong programming usage.
518 			 *
519 			 * Before warning check if this absolute symbol
520 			 * relocation is harmless.
521 			 */
522 			if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
523 				continue;
524 
525 			if (!printed) {
526 				printf("WARNING: Absolute relocations"
527 					" present\n");
528 				printf("Offset     Info     Type     Sym.Value "
529 					"Sym.Name\n");
530 				printed = 1;
531 			}
532 
533 			printf("%08x %08x %10s %08x  %s\n",
534 				rel->r_offset,
535 				rel->r_info,
536 				rel_type(ELF32_R_TYPE(rel->r_info)),
537 				sym->st_value,
538 				name);
539 		}
540 	}
541 
542 	if (printed)
543 		printf("\n");
544 }
545 
546 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
547 			int use_real_mode)
548 {
549 	int i;
550 	/* Walk through the relocations */
551 	for (i = 0; i < ehdr.e_shnum; i++) {
552 		char *sym_strtab;
553 		Elf32_Sym *sh_symtab;
554 		struct section *sec_applies, *sec_symtab;
555 		int j;
556 		struct section *sec = &secs[i];
557 
558 		if (sec->shdr.sh_type != SHT_REL) {
559 			continue;
560 		}
561 		sec_symtab  = sec->link;
562 		sec_applies = &secs[sec->shdr.sh_info];
563 		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
564 			continue;
565 		}
566 		sh_symtab = sec_symtab->symtab;
567 		sym_strtab = sec_symtab->link->strtab;
568 		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
569 			Elf32_Rel *rel;
570 			Elf32_Sym *sym;
571 			unsigned r_type;
572 			const char *symname;
573 			rel = &sec->reltab[j];
574 			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
575 			r_type = ELF32_R_TYPE(rel->r_info);
576 
577 			switch (r_type) {
578 			case R_386_NONE:
579 			case R_386_PC32:
580 			case R_386_PC16:
581 			case R_386_PC8:
582 				/*
583 				 * NONE can be ignored and and PC relative
584 				 * relocations don't need to be adjusted.
585 				 */
586 				break;
587 
588 			case R_386_16:
589 				symname = sym_name(sym_strtab, sym);
590 				if (!use_real_mode)
591 					goto bad;
592 				if (sym->st_shndx == SHN_ABS) {
593 					if (is_reloc(S_ABS, symname))
594 						break;
595 					else if (!is_reloc(S_SEG, symname))
596 						goto bad;
597 				} else {
598 					if (is_reloc(S_LIN, symname))
599 						goto bad;
600 					else
601 						break;
602 				}
603 				visit(rel, sym);
604 				break;
605 
606 			case R_386_32:
607 				symname = sym_name(sym_strtab, sym);
608 				if (sym->st_shndx == SHN_ABS) {
609 					if (is_reloc(S_ABS, symname))
610 						break;
611 					else if (!is_reloc(S_REL, symname))
612 						goto bad;
613 				} else {
614 					if (use_real_mode &&
615 					    !is_reloc(S_LIN, symname))
616 						break;
617 				}
618 				visit(rel, sym);
619 				break;
620 			default:
621 				die("Unsupported relocation type: %s (%d)\n",
622 				    rel_type(r_type), r_type);
623 				break;
624 			bad:
625 				symname = sym_name(sym_strtab, sym);
626 				die("Invalid %s relocation: %s\n",
627 				    rel_type(r_type), symname);
628 			}
629 		}
630 	}
631 }
632 
633 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
634 {
635 	if (ELF32_R_TYPE(rel->r_info) == R_386_16)
636 		reloc16_count++;
637 	else
638 		reloc_count++;
639 }
640 
641 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
642 {
643 	/* Remember the address that needs to be adjusted. */
644 	if (ELF32_R_TYPE(rel->r_info) == R_386_16)
645 		relocs16[reloc16_idx++] = rel->r_offset;
646 	else
647 		relocs[reloc_idx++] = rel->r_offset;
648 }
649 
650 static int cmp_relocs(const void *va, const void *vb)
651 {
652 	const unsigned long *a, *b;
653 	a = va; b = vb;
654 	return (*a == *b)? 0 : (*a > *b)? 1 : -1;
655 }
656 
657 static int write32(unsigned int v, FILE *f)
658 {
659 	unsigned char buf[4];
660 
661 	put_unaligned_le32(v, buf);
662 	return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
663 }
664 
665 static void emit_relocs(int as_text, int use_real_mode)
666 {
667 	int i;
668 	/* Count how many relocations I have and allocate space for them. */
669 	reloc_count = 0;
670 	walk_relocs(count_reloc, use_real_mode);
671 	relocs = malloc(reloc_count * sizeof(relocs[0]));
672 	if (!relocs) {
673 		die("malloc of %d entries for relocs failed\n",
674 			reloc_count);
675 	}
676 
677 	relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
678 	if (!relocs16) {
679 		die("malloc of %d entries for relocs16 failed\n",
680 			reloc16_count);
681 	}
682 	/* Collect up the relocations */
683 	reloc_idx = 0;
684 	walk_relocs(collect_reloc, use_real_mode);
685 
686 	if (reloc16_count && !use_real_mode)
687 		die("Segment relocations found but --realmode not specified\n");
688 
689 	/* Order the relocations for more efficient processing */
690 	qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
691 	qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
692 
693 	/* Print the relocations */
694 	if (as_text) {
695 		/* Print the relocations in a form suitable that
696 		 * gas will like.
697 		 */
698 		printf(".section \".data.reloc\",\"a\"\n");
699 		printf(".balign 4\n");
700 		if (use_real_mode) {
701 			printf("\t.long %lu\n", reloc16_count);
702 			for (i = 0; i < reloc16_count; i++)
703 				printf("\t.long 0x%08lx\n", relocs16[i]);
704 			printf("\t.long %lu\n", reloc_count);
705 			for (i = 0; i < reloc_count; i++) {
706 				printf("\t.long 0x%08lx\n", relocs[i]);
707 			}
708 		} else {
709 			/* Print a stop */
710 			printf("\t.long 0x%08lx\n", (unsigned long)0);
711 			for (i = 0; i < reloc_count; i++) {
712 				printf("\t.long 0x%08lx\n", relocs[i]);
713 			}
714 		}
715 
716 		printf("\n");
717 	}
718 	else {
719 		if (use_real_mode) {
720 			write32(reloc16_count, stdout);
721 			for (i = 0; i < reloc16_count; i++)
722 				write32(relocs16[i], stdout);
723 			write32(reloc_count, stdout);
724 
725 			/* Now print each relocation */
726 			for (i = 0; i < reloc_count; i++)
727 				write32(relocs[i], stdout);
728 		} else {
729 			/* Print a stop */
730 			write32(0, stdout);
731 
732 			/* Now print each relocation */
733 			for (i = 0; i < reloc_count; i++) {
734 				write32(relocs[i], stdout);
735 			}
736 		}
737 	}
738 }
739 
740 static void usage(void)
741 {
742 	die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
743 }
744 
745 int main(int argc, char **argv)
746 {
747 	int show_absolute_syms, show_absolute_relocs;
748 	int as_text, use_real_mode;
749 	const char *fname;
750 	FILE *fp;
751 	int i;
752 
753 	show_absolute_syms = 0;
754 	show_absolute_relocs = 0;
755 	as_text = 0;
756 	use_real_mode = 0;
757 	fname = NULL;
758 	for (i = 1; i < argc; i++) {
759 		char *arg = argv[i];
760 		if (*arg == '-') {
761 			if (strcmp(arg, "--abs-syms") == 0) {
762 				show_absolute_syms = 1;
763 				continue;
764 			}
765 			if (strcmp(arg, "--abs-relocs") == 0) {
766 				show_absolute_relocs = 1;
767 				continue;
768 			}
769 			if (strcmp(arg, "--text") == 0) {
770 				as_text = 1;
771 				continue;
772 			}
773 			if (strcmp(arg, "--realmode") == 0) {
774 				use_real_mode = 1;
775 				continue;
776 			}
777 		}
778 		else if (!fname) {
779 			fname = arg;
780 			continue;
781 		}
782 		usage();
783 	}
784 	if (!fname) {
785 		usage();
786 	}
787 	regex_init(use_real_mode);
788 	fp = fopen(fname, "r");
789 	if (!fp) {
790 		die("Cannot open %s: %s\n",
791 			fname, strerror(errno));
792 	}
793 	read_ehdr(fp);
794 	read_shdrs(fp);
795 	read_strtabs(fp);
796 	read_symtabs(fp);
797 	read_relocs(fp);
798 	if (show_absolute_syms) {
799 		print_absolute_symbols();
800 		return 0;
801 	}
802 	if (show_absolute_relocs) {
803 		print_absolute_relocs();
804 		return 0;
805 	}
806 	emit_relocs(as_text, use_real_mode);
807 	return 0;
808 }
809