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authorThomas Gleixner <tglx@linutronix.de>2007-10-11 05:16:43 -0400
committerThomas Gleixner <tglx@linutronix.de>2007-10-11 05:16:43 -0400
commit0530bf37cebcf22a73652937c2340bc1ebd92000 (patch)
treeac2918d5eca7b0775875ad81fe98a0248ae5924f /arch/x86/boot/compressed/relocs.c
parent19d8d79ccfd2fb67b1eb86e3c634a2e68a4c4b11 (diff)
i386: move boot
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/boot/compressed/relocs.c')
-rw-r--r--arch/x86/boot/compressed/relocs.c631
1 files changed, 631 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c
new file mode 100644
index 000000000000..2d77ee728f92
--- /dev/null
+++ b/arch/x86/boot/compressed/relocs.c
@@ -0,0 +1,631 @@
1#include <stdio.h>
2#include <stdarg.h>
3#include <stdlib.h>
4#include <stdint.h>
5#include <string.h>
6#include <errno.h>
7#include <unistd.h>
8#include <elf.h>
9#include <byteswap.h>
10#define USE_BSD
11#include <endian.h>
12
13#define MAX_SHDRS 100
14#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
15static Elf32_Ehdr ehdr;
16static Elf32_Shdr shdr[MAX_SHDRS];
17static Elf32_Sym *symtab[MAX_SHDRS];
18static Elf32_Rel *reltab[MAX_SHDRS];
19static char *strtab[MAX_SHDRS];
20static unsigned long reloc_count, reloc_idx;
21static unsigned long *relocs;
22
23/*
24 * Following symbols have been audited. There values are constant and do
25 * not change if bzImage is loaded at a different physical address than
26 * the address for which it has been compiled. Don't warn user about
27 * absolute relocations present w.r.t these symbols.
28 */
29static const char* safe_abs_relocs[] = {
30 "__kernel_vsyscall",
31 "__kernel_rt_sigreturn",
32 "__kernel_sigreturn",
33 "SYSENTER_RETURN",
34 "VDSO_NOTE_MASK",
35 "xen_irq_disable_direct_reloc",
36 "xen_save_fl_direct_reloc",
37};
38
39static int is_safe_abs_reloc(const char* sym_name)
40{
41 int i, array_size;
42
43 array_size = sizeof(safe_abs_relocs)/sizeof(char*);
44
45 for(i = 0; i < array_size; i++) {
46 if (!strcmp(sym_name, safe_abs_relocs[i]))
47 /* Match found */
48 return 1;
49 }
50 if (strncmp(sym_name, "__crc_", 6) == 0)
51 return 1;
52 return 0;
53}
54
55static void die(char *fmt, ...)
56{
57 va_list ap;
58 va_start(ap, fmt);
59 vfprintf(stderr, fmt, ap);
60 va_end(ap);
61 exit(1);
62}
63
64static const char *sym_type(unsigned type)
65{
66 static const char *type_name[] = {
67#define SYM_TYPE(X) [X] = #X
68 SYM_TYPE(STT_NOTYPE),
69 SYM_TYPE(STT_OBJECT),
70 SYM_TYPE(STT_FUNC),
71 SYM_TYPE(STT_SECTION),
72 SYM_TYPE(STT_FILE),
73 SYM_TYPE(STT_COMMON),
74 SYM_TYPE(STT_TLS),
75#undef SYM_TYPE
76 };
77 const char *name = "unknown sym type name";
78 if (type < ARRAY_SIZE(type_name)) {
79 name = type_name[type];
80 }
81 return name;
82}
83
84static const char *sym_bind(unsigned bind)
85{
86 static const char *bind_name[] = {
87#define SYM_BIND(X) [X] = #X
88 SYM_BIND(STB_LOCAL),
89 SYM_BIND(STB_GLOBAL),
90 SYM_BIND(STB_WEAK),
91#undef SYM_BIND
92 };
93 const char *name = "unknown sym bind name";
94 if (bind < ARRAY_SIZE(bind_name)) {
95 name = bind_name[bind];
96 }
97 return name;
98}
99
100static const char *sym_visibility(unsigned visibility)
101{
102 static const char *visibility_name[] = {
103#define SYM_VISIBILITY(X) [X] = #X
104 SYM_VISIBILITY(STV_DEFAULT),
105 SYM_VISIBILITY(STV_INTERNAL),
106 SYM_VISIBILITY(STV_HIDDEN),
107 SYM_VISIBILITY(STV_PROTECTED),
108#undef SYM_VISIBILITY
109 };
110 const char *name = "unknown sym visibility name";
111 if (visibility < ARRAY_SIZE(visibility_name)) {
112 name = visibility_name[visibility];
113 }
114 return name;
115}
116
117static const char *rel_type(unsigned type)
118{
119 static const char *type_name[] = {
120#define REL_TYPE(X) [X] = #X
121 REL_TYPE(R_386_NONE),
122 REL_TYPE(R_386_32),
123 REL_TYPE(R_386_PC32),
124 REL_TYPE(R_386_GOT32),
125 REL_TYPE(R_386_PLT32),
126 REL_TYPE(R_386_COPY),
127 REL_TYPE(R_386_GLOB_DAT),
128 REL_TYPE(R_386_JMP_SLOT),
129 REL_TYPE(R_386_RELATIVE),
130 REL_TYPE(R_386_GOTOFF),
131 REL_TYPE(R_386_GOTPC),
132#undef REL_TYPE
133 };
134 const char *name = "unknown type rel type name";
135 if (type < ARRAY_SIZE(type_name)) {
136 name = type_name[type];
137 }
138 return name;
139}
140
141static const char *sec_name(unsigned shndx)
142{
143 const char *sec_strtab;
144 const char *name;
145 sec_strtab = strtab[ehdr.e_shstrndx];
146 name = "<noname>";
147 if (shndx < ehdr.e_shnum) {
148 name = sec_strtab + shdr[shndx].sh_name;
149 }
150 else if (shndx == SHN_ABS) {
151 name = "ABSOLUTE";
152 }
153 else if (shndx == SHN_COMMON) {
154 name = "COMMON";
155 }
156 return name;
157}
158
159static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
160{
161 const char *name;
162 name = "<noname>";
163 if (sym->st_name) {
164 name = sym_strtab + sym->st_name;
165 }
166 else {
167 name = sec_name(shdr[sym->st_shndx].sh_name);
168 }
169 return name;
170}
171
172
173
174#if BYTE_ORDER == LITTLE_ENDIAN
175#define le16_to_cpu(val) (val)
176#define le32_to_cpu(val) (val)
177#endif
178#if BYTE_ORDER == BIG_ENDIAN
179#define le16_to_cpu(val) bswap_16(val)
180#define le32_to_cpu(val) bswap_32(val)
181#endif
182
183static uint16_t elf16_to_cpu(uint16_t val)
184{
185 return le16_to_cpu(val);
186}
187
188static uint32_t elf32_to_cpu(uint32_t val)
189{
190 return le32_to_cpu(val);
191}
192
193static void read_ehdr(FILE *fp)
194{
195 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
196 die("Cannot read ELF header: %s\n",
197 strerror(errno));
198 }
199 if (memcmp(ehdr.e_ident, ELFMAG, 4) != 0) {
200 die("No ELF magic\n");
201 }
202 if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
203 die("Not a 32 bit executable\n");
204 }
205 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
206 die("Not a LSB ELF executable\n");
207 }
208 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
209 die("Unknown ELF version\n");
210 }
211 /* Convert the fields to native endian */
212 ehdr.e_type = elf16_to_cpu(ehdr.e_type);
213 ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
214 ehdr.e_version = elf32_to_cpu(ehdr.e_version);
215 ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
216 ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
217 ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
218 ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
219 ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
220 ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
221 ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
222 ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
223 ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
224 ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
225
226 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
227 die("Unsupported ELF header type\n");
228 }
229 if (ehdr.e_machine != EM_386) {
230 die("Not for x86\n");
231 }
232 if (ehdr.e_version != EV_CURRENT) {
233 die("Unknown ELF version\n");
234 }
235 if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
236 die("Bad Elf header size\n");
237 }
238 if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
239 die("Bad program header entry\n");
240 }
241 if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
242 die("Bad section header entry\n");
243 }
244 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
245 die("String table index out of bounds\n");
246 }
247}
248
249static void read_shdrs(FILE *fp)
250{
251 int i;
252 if (ehdr.e_shnum > MAX_SHDRS) {
253 die("%d section headers supported: %d\n",
254 ehdr.e_shnum, MAX_SHDRS);
255 }
256 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
257 die("Seek to %d failed: %s\n",
258 ehdr.e_shoff, strerror(errno));
259 }
260 if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
261 die("Cannot read ELF section headers: %s\n",
262 strerror(errno));
263 }
264 for(i = 0; i < ehdr.e_shnum; i++) {
265 shdr[i].sh_name = elf32_to_cpu(shdr[i].sh_name);
266 shdr[i].sh_type = elf32_to_cpu(shdr[i].sh_type);
267 shdr[i].sh_flags = elf32_to_cpu(shdr[i].sh_flags);
268 shdr[i].sh_addr = elf32_to_cpu(shdr[i].sh_addr);
269 shdr[i].sh_offset = elf32_to_cpu(shdr[i].sh_offset);
270 shdr[i].sh_size = elf32_to_cpu(shdr[i].sh_size);
271 shdr[i].sh_link = elf32_to_cpu(shdr[i].sh_link);
272 shdr[i].sh_info = elf32_to_cpu(shdr[i].sh_info);
273 shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
274 shdr[i].sh_entsize = elf32_to_cpu(shdr[i].sh_entsize);
275 }
276
277}
278
279static void read_strtabs(FILE *fp)
280{
281 int i;
282 for(i = 0; i < ehdr.e_shnum; i++) {
283 if (shdr[i].sh_type != SHT_STRTAB) {
284 continue;
285 }
286 strtab[i] = malloc(shdr[i].sh_size);
287 if (!strtab[i]) {
288 die("malloc of %d bytes for strtab failed\n",
289 shdr[i].sh_size);
290 }
291 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
292 die("Seek to %d failed: %s\n",
293 shdr[i].sh_offset, strerror(errno));
294 }
295 if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
296 die("Cannot read symbol table: %s\n",
297 strerror(errno));
298 }
299 }
300}
301
302static void read_symtabs(FILE *fp)
303{
304 int i,j;
305 for(i = 0; i < ehdr.e_shnum; i++) {
306 if (shdr[i].sh_type != SHT_SYMTAB) {
307 continue;
308 }
309 symtab[i] = malloc(shdr[i].sh_size);
310 if (!symtab[i]) {
311 die("malloc of %d bytes for symtab failed\n",
312 shdr[i].sh_size);
313 }
314 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
315 die("Seek to %d failed: %s\n",
316 shdr[i].sh_offset, strerror(errno));
317 }
318 if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
319 die("Cannot read symbol table: %s\n",
320 strerror(errno));
321 }
322 for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
323 symtab[i][j].st_name = elf32_to_cpu(symtab[i][j].st_name);
324 symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
325 symtab[i][j].st_size = elf32_to_cpu(symtab[i][j].st_size);
326 symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
327 }
328 }
329}
330
331
332static void read_relocs(FILE *fp)
333{
334 int i,j;
335 for(i = 0; i < ehdr.e_shnum; i++) {
336 if (shdr[i].sh_type != SHT_REL) {
337 continue;
338 }
339 reltab[i] = malloc(shdr[i].sh_size);
340 if (!reltab[i]) {
341 die("malloc of %d bytes for relocs failed\n",
342 shdr[i].sh_size);
343 }
344 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
345 die("Seek to %d failed: %s\n",
346 shdr[i].sh_offset, strerror(errno));
347 }
348 if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
349 die("Cannot read symbol table: %s\n",
350 strerror(errno));
351 }
352 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
353 reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
354 reltab[i][j].r_info = elf32_to_cpu(reltab[i][j].r_info);
355 }
356 }
357}
358
359
360static void print_absolute_symbols(void)
361{
362 int i;
363 printf("Absolute symbols\n");
364 printf(" Num: Value Size Type Bind Visibility Name\n");
365 for(i = 0; i < ehdr.e_shnum; i++) {
366 char *sym_strtab;
367 Elf32_Sym *sh_symtab;
368 int j;
369 if (shdr[i].sh_type != SHT_SYMTAB) {
370 continue;
371 }
372 sh_symtab = symtab[i];
373 sym_strtab = strtab[shdr[i].sh_link];
374 for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
375 Elf32_Sym *sym;
376 const char *name;
377 sym = &symtab[i][j];
378 name = sym_name(sym_strtab, sym);
379 if (sym->st_shndx != SHN_ABS) {
380 continue;
381 }
382 printf("%5d %08x %5d %10s %10s %12s %s\n",
383 j, sym->st_value, sym->st_size,
384 sym_type(ELF32_ST_TYPE(sym->st_info)),
385 sym_bind(ELF32_ST_BIND(sym->st_info)),
386 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
387 name);
388 }
389 }
390 printf("\n");
391}
392
393static void print_absolute_relocs(void)
394{
395 int i, printed = 0;
396
397 for(i = 0; i < ehdr.e_shnum; i++) {
398 char *sym_strtab;
399 Elf32_Sym *sh_symtab;
400 unsigned sec_applies, sec_symtab;
401 int j;
402 if (shdr[i].sh_type != SHT_REL) {
403 continue;
404 }
405 sec_symtab = shdr[i].sh_link;
406 sec_applies = shdr[i].sh_info;
407 if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
408 continue;
409 }
410 sh_symtab = symtab[sec_symtab];
411 sym_strtab = strtab[shdr[sec_symtab].sh_link];
412 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
413 Elf32_Rel *rel;
414 Elf32_Sym *sym;
415 const char *name;
416 rel = &reltab[i][j];
417 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
418 name = sym_name(sym_strtab, sym);
419 if (sym->st_shndx != SHN_ABS) {
420 continue;
421 }
422
423 /* Absolute symbols are not relocated if bzImage is
424 * loaded at a non-compiled address. Display a warning
425 * to user at compile time about the absolute
426 * relocations present.
427 *
428 * User need to audit the code to make sure
429 * some symbols which should have been section
430 * relative have not become absolute because of some
431 * linker optimization or wrong programming usage.
432 *
433 * Before warning check if this absolute symbol
434 * relocation is harmless.
435 */
436 if (is_safe_abs_reloc(name))
437 continue;
438
439 if (!printed) {
440 printf("WARNING: Absolute relocations"
441 " present\n");
442 printf("Offset Info Type Sym.Value "
443 "Sym.Name\n");
444 printed = 1;
445 }
446
447 printf("%08x %08x %10s %08x %s\n",
448 rel->r_offset,
449 rel->r_info,
450 rel_type(ELF32_R_TYPE(rel->r_info)),
451 sym->st_value,
452 name);
453 }
454 }
455
456 if (printed)
457 printf("\n");
458}
459
460static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
461{
462 int i;
463 /* Walk through the relocations */
464 for(i = 0; i < ehdr.e_shnum; i++) {
465 char *sym_strtab;
466 Elf32_Sym *sh_symtab;
467 unsigned sec_applies, sec_symtab;
468 int j;
469 if (shdr[i].sh_type != SHT_REL) {
470 continue;
471 }
472 sec_symtab = shdr[i].sh_link;
473 sec_applies = shdr[i].sh_info;
474 if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
475 continue;
476 }
477 sh_symtab = symtab[sec_symtab];
478 sym_strtab = strtab[shdr[sec_symtab].sh_link];
479 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
480 Elf32_Rel *rel;
481 Elf32_Sym *sym;
482 unsigned r_type;
483 rel = &reltab[i][j];
484 sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
485 r_type = ELF32_R_TYPE(rel->r_info);
486 /* Don't visit relocations to absolute symbols */
487 if (sym->st_shndx == SHN_ABS) {
488 continue;
489 }
490 if (r_type == R_386_PC32) {
491 /* PC relative relocations don't need to be adjusted */
492 }
493 else if (r_type == R_386_32) {
494 /* Visit relocations that need to be adjusted */
495 visit(rel, sym);
496 }
497 else {
498 die("Unsupported relocation type: %d\n", r_type);
499 }
500 }
501 }
502}
503
504static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
505{
506 reloc_count += 1;
507}
508
509static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
510{
511 /* Remember the address that needs to be adjusted. */
512 relocs[reloc_idx++] = rel->r_offset;
513}
514
515static int cmp_relocs(const void *va, const void *vb)
516{
517 const unsigned long *a, *b;
518 a = va; b = vb;
519 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
520}
521
522static void emit_relocs(int as_text)
523{
524 int i;
525 /* Count how many relocations I have and allocate space for them. */
526 reloc_count = 0;
527 walk_relocs(count_reloc);
528 relocs = malloc(reloc_count * sizeof(relocs[0]));
529 if (!relocs) {
530 die("malloc of %d entries for relocs failed\n",
531 reloc_count);
532 }
533 /* Collect up the relocations */
534 reloc_idx = 0;
535 walk_relocs(collect_reloc);
536
537 /* Order the relocations for more efficient processing */
538 qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
539
540 /* Print the relocations */
541 if (as_text) {
542 /* Print the relocations in a form suitable that
543 * gas will like.
544 */
545 printf(".section \".data.reloc\",\"a\"\n");
546 printf(".balign 4\n");
547 for(i = 0; i < reloc_count; i++) {
548 printf("\t .long 0x%08lx\n", relocs[i]);
549 }
550 printf("\n");
551 }
552 else {
553 unsigned char buf[4];
554 buf[0] = buf[1] = buf[2] = buf[3] = 0;
555 /* Print a stop */
556 printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
557 /* Now print each relocation */
558 for(i = 0; i < reloc_count; i++) {
559 buf[0] = (relocs[i] >> 0) & 0xff;
560 buf[1] = (relocs[i] >> 8) & 0xff;
561 buf[2] = (relocs[i] >> 16) & 0xff;
562 buf[3] = (relocs[i] >> 24) & 0xff;
563 printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
564 }
565 }
566}
567
568static void usage(void)
569{
570 die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
571}
572
573int main(int argc, char **argv)
574{
575 int show_absolute_syms, show_absolute_relocs;
576 int as_text;
577 const char *fname;
578 FILE *fp;
579 int i;
580
581 show_absolute_syms = 0;
582 show_absolute_relocs = 0;
583 as_text = 0;
584 fname = NULL;
585 for(i = 1; i < argc; i++) {
586 char *arg = argv[i];
587 if (*arg == '-') {
588 if (strcmp(argv[1], "--abs-syms") == 0) {
589 show_absolute_syms = 1;
590 continue;
591 }
592
593 if (strcmp(argv[1], "--abs-relocs") == 0) {
594 show_absolute_relocs = 1;
595 continue;
596 }
597 else if (strcmp(argv[1], "--text") == 0) {
598 as_text = 1;
599 continue;
600 }
601 }
602 else if (!fname) {
603 fname = arg;
604 continue;
605 }
606 usage();
607 }
608 if (!fname) {
609 usage();
610 }
611 fp = fopen(fname, "r");
612 if (!fp) {
613 die("Cannot open %s: %s\n",
614 fname, strerror(errno));
615 }
616 read_ehdr(fp);
617 read_shdrs(fp);
618 read_strtabs(fp);
619 read_symtabs(fp);
620 read_relocs(fp);
621 if (show_absolute_syms) {
622 print_absolute_symbols();
623 return 0;
624 }
625 if (show_absolute_relocs) {
626 print_absolute_relocs();
627 return 0;
628 }
629 emit_relocs(as_text);
630 return 0;
631}
generated by cgit v1.2.2 (git 2.25.0) at 2025-02-07 01:25:23 -0500