summaryrefslogtreecommitdiff
path: root/arch/x86/tools/relocs.c
blob: 04c5a44b968276ec3975acbe035acce8a438572d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
// SPDX-License-Identifier: GPL-2.0
/* This is included from relocs_32/64.c */

#define ElfW(type)		_ElfW(ELF_BITS, type)
#define _ElfW(bits, type)	__ElfW(bits, type)
#define __ElfW(bits, type)	Elf##bits##_##type

#define Elf_Addr		ElfW(Addr)
#define Elf_Ehdr		ElfW(Ehdr)
#define Elf_Phdr		ElfW(Phdr)
#define Elf_Shdr		ElfW(Shdr)
#define Elf_Sym			ElfW(Sym)

static Elf_Ehdr		ehdr;
static unsigned long	shnum;
static unsigned int	shstrndx;

struct relocs {
	uint32_t	*offset;
	unsigned long	count;
	unsigned long	size;
};

static struct relocs relocs16;
static struct relocs relocs32;
#if ELF_BITS == 64
static struct relocs relocs32neg;
static struct relocs relocs64;
#endif

struct section {
	Elf_Shdr       shdr;
	struct section *link;
	Elf_Sym        *symtab;
	Elf_Rel        *reltab;
	char           *strtab;
};
static struct section *secs;

static const char * const sym_regex_kernel[S_NSYMTYPES] = {
/*
 * Following symbols have been audited. There values are constant and do
 * not change if bzImage is loaded at a different physical address than
 * the address for which it has been compiled. Don't warn user about
 * absolute relocations present w.r.t these symbols.
 */
	[S_ABS] =
	"^(xen_irq_disable_direct_reloc$|"
	"xen_save_fl_direct_reloc$|"
	"VDSO|"
	"__crc_)",

/*
 * These symbols are known to be relative, even if the linker marks them
 * as absolute (typically defined outside any section in the linker script.)
 */
	[S_REL] =
	"^(__init_(begin|end)|"
	"__x86_cpu_dev_(start|end)|"
	"(__parainstructions|__alt_instructions)(|_end)|"
	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
	"__(start|end)_pci_.*|"
	"__(start|end)_builtin_fw|"
	"__(start|stop)___ksymtab(|_gpl)|"
	"__(start|stop)___kcrctab(|_gpl)|"
	"__(start|stop)___param|"
	"__(start|stop)___modver|"
	"__(start|stop)___bug_table|"
	"__tracedata_(start|end)|"
	"__(start|stop)_notes|"
	"__end_rodata|"
	"__end_rodata_aligned|"
	"__initramfs_start|"
	"(jiffies|jiffies_64)|"
#if ELF_BITS == 64
	"__per_cpu_load|"
	"init_per_cpu__.*|"
	"__end_rodata_hpage_align|"
#endif
	"__vvar_page|"
	"_end)$"
};


static const char * const sym_regex_realmode[S_NSYMTYPES] = {
/*
 * These symbols are known to be relative, even if the linker marks them
 * as absolute (typically defined outside any section in the linker script.)
 */
	[S_REL] =
	"^pa_",

/*
 * These are 16-bit segment symbols when compiling 16-bit code.
 */
	[S_SEG] =
	"^real_mode_seg$",

/*
 * These are offsets belonging to segments, as opposed to linear addresses,
 * when compiling 16-bit code.
 */
	[S_LIN] =
	"^pa_",
};

static const char * const *sym_regex;

static regex_t sym_regex_c[S_NSYMTYPES];
static int is_reloc(enum symtype type, const char *sym_name)
{
	return sym_regex[type] &&
		!regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
}

static void regex_init(int use_real_mode)
{
        char errbuf[128];
        int err;
	int i;

	if (use_real_mode)
		sym_regex = sym_regex_realmode;
	else
		sym_regex = sym_regex_kernel;

	for (i = 0; i < S_NSYMTYPES; i++) {
		if (!sym_regex[i])
			continue;

		err = regcomp(&sym_regex_c[i], sym_regex[i],
			      REG_EXTENDED|REG_NOSUB);

		if (err) {
			regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf));
			die("%s", errbuf);
		}
        }
}

static const char *sym_type(unsigned type)
{
	static const char *type_name[] = {
#define SYM_TYPE(X) [X] = #X
		SYM_TYPE(STT_NOTYPE),
		SYM_TYPE(STT_OBJECT),
		SYM_TYPE(STT_FUNC),
		SYM_TYPE(STT_SECTION),
		SYM_TYPE(STT_FILE),
		SYM_TYPE(STT_COMMON),
		SYM_TYPE(STT_TLS),
#undef SYM_TYPE
	};
	const char *name = "unknown sym type name";
	if (type < ARRAY_SIZE(type_name)) {
		name = type_name[type];
	}
	return name;
}

static const char *sym_bind(unsigned bind)
{
	static const char *bind_name[] = {
#define SYM_BIND(X) [X] = #X
		SYM_BIND(STB_LOCAL),
		SYM_BIND(STB_GLOBAL),
		SYM_BIND(STB_WEAK),
#undef SYM_BIND
	};
	const char *name = "unknown sym bind name";
	if (bind < ARRAY_SIZE(bind_name)) {
		name = bind_name[bind];
	}
	return name;
}

static const char *sym_visibility(unsigned visibility)
{
	static const char *visibility_name[] = {
#define SYM_VISIBILITY(X) [X] = #X
		SYM_VISIBILITY(STV_DEFAULT),
		SYM_VISIBILITY(STV_INTERNAL),
		SYM_VISIBILITY(STV_HIDDEN),
		SYM_VISIBILITY(STV_PROTECTED),
#undef SYM_VISIBILITY
	};
	const char *name = "unknown sym visibility name";
	if (visibility < ARRAY_SIZE(visibility_name)) {
		name = visibility_name[visibility];
	}
	return name;
}

static const char *rel_type(unsigned type)
{
	static const char *type_name[] = {
#define REL_TYPE(X) [X] = #X
#if ELF_BITS == 64
		REL_TYPE(R_X86_64_NONE),
		REL_TYPE(R_X86_64_64),
		REL_TYPE(R_X86_64_PC64),
		REL_TYPE(R_X86_64_PC32),
		REL_TYPE(R_X86_64_GOT32),
		REL_TYPE(R_X86_64_PLT32),
		REL_TYPE(R_X86_64_COPY),
		REL_TYPE(R_X86_64_GLOB_DAT),
		REL_TYPE(R_X86_64_JUMP_SLOT),
		REL_TYPE(R_X86_64_RELATIVE),
		REL_TYPE(R_X86_64_GOTPCREL),
		REL_TYPE(R_X86_64_32),
		REL_TYPE(R_X86_64_32S),
		REL_TYPE(R_X86_64_16),
		REL_TYPE(R_X86_64_PC16),
		REL_TYPE(R_X86_64_8),
		REL_TYPE(R_X86_64_PC8),
#else
		REL_TYPE(R_386_NONE),
		REL_TYPE(R_386_32),
		REL_TYPE(R_386_PC32),
		REL_TYPE(R_386_GOT32),
		REL_TYPE(R_386_PLT32),
		REL_TYPE(R_386_COPY),
		REL_TYPE(R_386_GLOB_DAT),
		REL_TYPE(R_386_JMP_SLOT),
		REL_TYPE(R_386_RELATIVE),
		REL_TYPE(R_386_GOTOFF),
		REL_TYPE(R_386_GOTPC),
		REL_TYPE(R_386_8),
		REL_TYPE(R_386_PC8),
		REL_TYPE(R_386_16),
		REL_TYPE(R_386_PC16),
#endif
#undef REL_TYPE
	};
	const char *name = "unknown type rel type name";
	if (type < ARRAY_SIZE(type_name) && type_name[type]) {
		name = type_name[type];
	}
	return name;
}

static const char *sec_name(unsigned shndx)
{
	const char *sec_strtab;
	const char *name;
	sec_strtab = secs[shstrndx].strtab;
	name = "<noname>";
	if (shndx < shnum) {
		name = sec_strtab + secs[shndx].shdr.sh_name;
	}
	else if (shndx == SHN_ABS) {
		name = "ABSOLUTE";
	}
	else if (shndx == SHN_COMMON) {
		name = "COMMON";
	}
	return name;
}

static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
{
	const char *name;
	name = "<noname>";
	if (sym->st_name) {
		name = sym_strtab + sym->st_name;
	}
	else {
		name = sec_name(sym->st_shndx);
	}
	return name;
}

static Elf_Sym *sym_lookup(const char *symname)
{
	int i;
	for (i = 0; i < shnum; i++) {
		struct section *sec = &secs[i];
		long nsyms;
		char *strtab;
		Elf_Sym *symtab;
		Elf_Sym *sym;

		if (sec->shdr.sh_type != SHT_SYMTAB)
			continue;

		nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
		symtab = sec->symtab;
		strtab = sec->link->strtab;

		for (sym = symtab; --nsyms >= 0; sym++) {
			if (!sym->st_name)
				continue;
			if (strcmp(symname, strtab + sym->st_name) == 0)
				return sym;
		}
	}
	return 0;
}

#if BYTE_ORDER == LITTLE_ENDIAN
#define le16_to_cpu(val) (val)
#define le32_to_cpu(val) (val)
#define le64_to_cpu(val) (val)
#endif
#if BYTE_ORDER == BIG_ENDIAN
#define le16_to_cpu(val) bswap_16(val)
#define le32_to_cpu(val) bswap_32(val)
#define le64_to_cpu(val) bswap_64(val)
#endif

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

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

#define elf_half_to_cpu(x)	elf16_to_cpu(x)
#define elf_word_to_cpu(x)	elf32_to_cpu(x)

#if ELF_BITS == 64
static uint64_t elf64_to_cpu(uint64_t val)
{
        return le64_to_cpu(val);
}
#define elf_addr_to_cpu(x)	elf64_to_cpu(x)
#define elf_off_to_cpu(x)	elf64_to_cpu(x)
#define elf_xword_to_cpu(x)	elf64_to_cpu(x)
#else
#define elf_addr_to_cpu(x)	elf32_to_cpu(x)
#define elf_off_to_cpu(x)	elf32_to_cpu(x)
#define elf_xword_to_cpu(x)	elf32_to_cpu(x)
#endif

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

	shnum = ehdr.e_shnum;
	shstrndx = ehdr.e_shstrndx;

	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
		die("Unsupported ELF header type\n");
	if (ehdr.e_machine != ELF_MACHINE)
		die("Not for %s\n", ELF_MACHINE_NAME);
	if (ehdr.e_version != EV_CURRENT)
		die("Unknown ELF version\n");
	if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
		die("Bad Elf header size\n");
	if (ehdr.e_phentsize != sizeof(Elf_Phdr))
		die("Bad program header entry\n");
	if (ehdr.e_shentsize != sizeof(Elf_Shdr))
		die("Bad section header entry\n");


	if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
		Elf_Shdr shdr;

		if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
			die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));

		if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
			die("Cannot read initial ELF section header: %s\n", strerror(errno));

		if (shnum == SHN_UNDEF)
			shnum = elf_xword_to_cpu(shdr.sh_size);

		if (shstrndx == SHN_XINDEX)
			shstrndx = elf_word_to_cpu(shdr.sh_link);
	}

	if (shstrndx >= shnum)
		die("String table index out of bounds\n");
}

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

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

}

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

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


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


static void print_absolute_symbols(void)
{
	int i;
	const char *format;

	if (ELF_BITS == 64)
		format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
	else
		format = "%5d %08"PRIx32"  %5"PRId32" %10s %10s %12s %s\n";

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

		if (sec->shdr.sh_type != SHT_SYMTAB) {
			continue;
		}
		sym_strtab = sec->link->strtab;
		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
			Elf_Sym *sym;
			const char *name;
			sym = &sec->symtab[j];
			name = sym_name(sym_strtab, sym);
			if (sym->st_shndx != SHN_ABS) {
				continue;
			}
			printf(format,
				j, sym->st_value, sym->st_size,
				sym_type(ELF_ST_TYPE(sym->st_info)),
				sym_bind(ELF_ST_BIND(sym->st_info)),
				sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
				name);
		}
	}
	printf("\n");
}

static void print_absolute_relocs(void)
{
	int i, printed = 0;
	const char *format;

	if (ELF_BITS == 64)
		format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64"  %s\n";
	else
		format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32"  %s\n";

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

			/* Absolute symbols are not relocated if bzImage is
			 * loaded at a non-compiled address. Display a warning
			 * to user at compile time about the absolute
			 * relocations present.
			 *
			 * User need to audit the code to make sure
			 * some symbols which should have been section
			 * relative have not become absolute because of some
			 * linker optimization or wrong programming usage.
			 *
			 * Before warning check if this absolute symbol
			 * relocation is harmless.
			 */
			if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
				continue;

			if (!printed) {
				printf("WARNING: Absolute relocations"
					" present\n");
				printf("Offset     Info     Type     Sym.Value "
					"Sym.Name\n");
				printed = 1;
			}

			printf(format,
				rel->r_offset,
				rel->r_info,
				rel_type(ELF_R_TYPE(rel->r_info)),
				sym->st_value,
				name);
		}
	}

	if (printed)
		printf("\n");
}

static void add_reloc(struct relocs *r, uint32_t offset)
{
	if (r->count == r->size) {
		unsigned long newsize = r->size + 50000;
		void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));

		if (!mem)
			die("realloc of %ld entries for relocs failed\n",
                                newsize);
		r->offset = mem;
		r->size = newsize;
	}
	r->offset[r->count++] = offset;
}

static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
			Elf_Sym *sym, const char *symname))
{
	int i;
	/* Walk through the relocations */
	for (i = 0; i < shnum; i++) {
		char *sym_strtab;
		Elf_Sym *sh_symtab;
		struct section *sec_applies, *sec_symtab;
		int j;
		struct section *sec = &secs[i];

		if (sec->shdr.sh_type != SHT_REL_TYPE) {
			continue;
		}
		sec_symtab  = sec->link;
		sec_applies = &secs[sec->shdr.sh_info];
		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = sec_symtab->symtab;
		sym_strtab = sec_symtab->link->strtab;
		for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
			Elf_Rel *rel = &sec->reltab[j];
			Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
			const char *symname = sym_name(sym_strtab, sym);

			process(sec, rel, sym, symname);
		}
	}
}

/*
 * The .data..percpu section is a special case for x86_64 SMP kernels.
 * It is used to initialize the actual per_cpu areas and to provide
 * definitions for the per_cpu variables that correspond to their offsets
 * within the percpu area. Since the values of all of the symbols need
 * to be offsets from the start of the per_cpu area the virtual address
 * (sh_addr) of .data..percpu is 0 in SMP kernels.
 *
 * This means that:
 *
 *	Relocations that reference symbols in the per_cpu area do not
 *	need further relocation (since the value is an offset relative
 *	to the start of the per_cpu area that does not change).
 *
 *	Relocations that apply to the per_cpu area need to have their
 *	offset adjusted by by the value of __per_cpu_load to make them
 *	point to the correct place in the loaded image (because the
 *	virtual address of .data..percpu is 0).
 *
 * For non SMP kernels .data..percpu is linked as part of the normal
 * kernel data and does not require special treatment.
 *
 */
static int per_cpu_shndx	= -1;
static Elf_Addr per_cpu_load_addr;

static void percpu_init(void)
{
	int i;
	for (i = 0; i < shnum; i++) {
		ElfW(Sym) *sym;
		if (strcmp(sec_name(i), ".data..percpu"))
			continue;

		if (secs[i].shdr.sh_addr != 0)	/* non SMP kernel */
			return;

		sym = sym_lookup("__per_cpu_load");
		if (!sym)
			die("can't find __per_cpu_load\n");

		per_cpu_shndx = i;
		per_cpu_load_addr = sym->st_value;
		return;
	}
}

#if ELF_BITS == 64

/*
 * Check to see if a symbol lies in the .data..percpu section.
 *
 * The linker incorrectly associates some symbols with the
 * .data..percpu section so we also need to check the symbol
 * name to make sure that we classify the symbol correctly.
 *
 * The GNU linker incorrectly associates:
 *	__init_begin
 *	__per_cpu_load
 *
 * The "gold" linker incorrectly associates:
 *	init_per_cpu__fixed_percpu_data
 *	init_per_cpu__gdt_page
 */
static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
{
	return (sym->st_shndx == per_cpu_shndx) &&
		strcmp(symname, "__init_begin") &&
		strcmp(symname, "__per_cpu_load") &&
		strncmp(symname, "init_per_cpu_", 13);
}


static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
		      const char *symname)
{
	unsigned r_type = ELF64_R_TYPE(rel->r_info);
	ElfW(Addr) offset = rel->r_offset;
	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);

	if (sym->st_shndx == SHN_UNDEF)
		return 0;

	/*
	 * Adjust the offset if this reloc applies to the percpu section.
	 */
	if (sec->shdr.sh_info == per_cpu_shndx)
		offset += per_cpu_load_addr;

	switch (r_type) {
	case R_X86_64_NONE:
		/* NONE can be ignored. */
		break;

	case R_X86_64_PC32:
	case R_X86_64_PLT32:
		/*
		 * PC relative relocations don't need to be adjusted unless
		 * referencing a percpu symbol.
		 *
		 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
		 */
		if (is_percpu_sym(sym, symname))
			add_reloc(&relocs32neg, offset);
		break;

	case R_X86_64_PC64:
		/*
		 * Only used by jump labels
		 */
		if (is_percpu_sym(sym, symname))
			die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
			    symname);
		break;

	case R_X86_64_32:
	case R_X86_64_32S:
	case R_X86_64_64:
		/*
		 * References to the percpu area don't need to be adjusted.
		 */
		if (is_percpu_sym(sym, symname))
			break;

		if (shn_abs) {
			/*
			 * Whitelisted absolute symbols do not require
			 * relocation.
			 */
			if (is_reloc(S_ABS, symname))
				break;

			die("Invalid absolute %s relocation: %s\n",
			    rel_type(r_type), symname);
			break;
		}

		/*
		 * Relocation offsets for 64 bit kernels are output
		 * as 32 bits and sign extended back to 64 bits when
		 * the relocations are processed.
		 * Make sure that the offset will fit.
		 */
		if ((int32_t)offset != (int64_t)offset)
			die("Relocation offset doesn't fit in 32 bits\n");

		if (r_type == R_X86_64_64)
			add_reloc(&relocs64, offset);
		else
			add_reloc(&relocs32, offset);
		break;

	default:
		die("Unsupported relocation type: %s (%d)\n",
		    rel_type(r_type), r_type);
		break;
	}

	return 0;
}

#else

static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
		      const char *symname)
{
	unsigned r_type = ELF32_R_TYPE(rel->r_info);
	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);

	switch (r_type) {
	case R_386_NONE:
	case R_386_PC32:
	case R_386_PC16:
	case R_386_PC8:
	case R_386_PLT32:
		/*
		 * NONE can be ignored and PC relative relocations don't need
		 * to be adjusted. Because sym must be defined, R_386_PLT32 can
		 * be treated the same way as R_386_PC32.
		 */
		break;

	case R_386_32:
		if (shn_abs) {
			/*
			 * Whitelisted absolute symbols do not require
			 * relocation.
			 */
			if (is_reloc(S_ABS, symname))
				break;

			die("Invalid absolute %s relocation: %s\n",
			    rel_type(r_type), symname);
			break;
		}

		add_reloc(&relocs32, rel->r_offset);
		break;

	default:
		die("Unsupported relocation type: %s (%d)\n",
		    rel_type(r_type), r_type);
		break;
	}

	return 0;
}

static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
			 const char *symname)
{
	unsigned r_type = ELF32_R_TYPE(rel->r_info);
	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);

	switch (r_type) {
	case R_386_NONE:
	case R_386_PC32:
	case R_386_PC16:
	case R_386_PC8:
	case R_386_PLT32:
		/*
		 * NONE can be ignored and PC relative relocations don't need
		 * to be adjusted. Because sym must be defined, R_386_PLT32 can
		 * be treated the same way as R_386_PC32.
		 */
		break;

	case R_386_16:
		if (shn_abs) {
			/*
			 * Whitelisted absolute symbols do not require
			 * relocation.
			 */
			if (is_reloc(S_ABS, symname))
				break;

			if (is_reloc(S_SEG, symname)) {
				add_reloc(&relocs16, rel->r_offset);
				break;
			}
		} else {
			if (!is_reloc(S_LIN, symname))
				break;
		}
		die("Invalid %s %s relocation: %s\n",
		    shn_abs ? "absolute" : "relative",
		    rel_type(r_type), symname);
		break;

	case R_386_32:
		if (shn_abs) {
			/*
			 * Whitelisted absolute symbols do not require
			 * relocation.
			 */
			if (is_reloc(S_ABS, symname))
				break;

			if (is_reloc(S_REL, symname)) {
				add_reloc(&relocs32, rel->r_offset);
				break;
			}
		} else {
			if (is_reloc(S_LIN, symname))
				add_reloc(&relocs32, rel->r_offset);
			break;
		}
		die("Invalid %s %s relocation: %s\n",
		    shn_abs ? "absolute" : "relative",
		    rel_type(r_type), symname);
		break;

	default:
		die("Unsupported relocation type: %s (%d)\n",
		    rel_type(r_type), r_type);
		break;
	}

	return 0;
}

#endif

static int cmp_relocs(const void *va, const void *vb)
{
	const uint32_t *a, *b;
	a = va; b = vb;
	return (*a == *b)? 0 : (*a > *b)? 1 : -1;
}

static void sort_relocs(struct relocs *r)
{
	qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
}

static int write32(uint32_t v, FILE *f)
{
	unsigned char buf[4];

	put_unaligned_le32(v, buf);
	return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
}

static int write32_as_text(uint32_t v, FILE *f)
{
	return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
}

static void emit_relocs(int as_text, int use_real_mode)
{
	int i;
	int (*write_reloc)(uint32_t, FILE *) = write32;
	int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
			const char *symname);

#if ELF_BITS == 64
	if (!use_real_mode)
		do_reloc = do_reloc64;
	else
		die("--realmode not valid for a 64-bit ELF file");
#else
	if (!use_real_mode)
		do_reloc = do_reloc32;
	else
		do_reloc = do_reloc_real;
#endif

	/* Collect up the relocations */
	walk_relocs(do_reloc);

	if (relocs16.count && !use_real_mode)
		die("Segment relocations found but --realmode not specified\n");

	/* Order the relocations for more efficient processing */
	sort_relocs(&relocs32);
#if ELF_BITS == 64
	sort_relocs(&relocs32neg);
	sort_relocs(&relocs64);
#else
	sort_relocs(&relocs16);
#endif

	/* Print the relocations */
	if (as_text) {
		/* Print the relocations in a form suitable that
		 * gas will like.
		 */
		printf(".section \".data.reloc\",\"a\"\n");
		printf(".balign 4\n");
		write_reloc = write32_as_text;
	}

	if (use_real_mode) {
		write_reloc(relocs16.count, stdout);
		for (i = 0; i < relocs16.count; i++)
			write_reloc(relocs16.offset[i], stdout);

		write_reloc(relocs32.count, stdout);
		for (i = 0; i < relocs32.count; i++)
			write_reloc(relocs32.offset[i], stdout);
	} else {
#if ELF_BITS == 64
		/* Print a stop */
		write_reloc(0, stdout);

		/* Now print each relocation */
		for (i = 0; i < relocs64.count; i++)
			write_reloc(relocs64.offset[i], stdout);

		/* Print a stop */
		write_reloc(0, stdout);

		/* Now print each inverse 32-bit relocation */
		for (i = 0; i < relocs32neg.count; i++)
			write_reloc(relocs32neg.offset[i], stdout);
#endif

		/* Print a stop */
		write_reloc(0, stdout);

		/* Now print each relocation */
		for (i = 0; i < relocs32.count; i++)
			write_reloc(relocs32.offset[i], stdout);
	}
}

/*
 * As an aid to debugging problems with different linkers
 * print summary information about the relocs.
 * Since different linkers tend to emit the sections in
 * different orders we use the section names in the output.
 */
static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
				const char *symname)
{
	printf("%s\t%s\t%s\t%s\n",
		sec_name(sec->shdr.sh_info),
		rel_type(ELF_R_TYPE(rel->r_info)),
		symname,
		sec_name(sym->st_shndx));
	return 0;
}

static void print_reloc_info(void)
{
	printf("reloc section\treloc type\tsymbol\tsymbol section\n");
	walk_relocs(do_reloc_info);
}

#if ELF_BITS == 64
# define process process_64
#else
# define process process_32
#endif

void process(FILE *fp, int use_real_mode, int as_text,
	     int show_absolute_syms, int show_absolute_relocs,
	     int show_reloc_info)
{
	regex_init(use_real_mode);
	read_ehdr(fp);
	read_shdrs(fp);
	read_strtabs(fp);
	read_symtabs(fp);
	read_relocs(fp);
	if (ELF_BITS == 64)
		percpu_init();
	if (show_absolute_syms) {
		print_absolute_symbols();
		return;
	}
	if (show_absolute_relocs) {
		print_absolute_relocs();
		return;
	}
	if (show_reloc_info) {
		print_reloc_info();
		return;
	}
	emit_relocs(as_text, use_real_mode);
}