aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ia64/kernel/module.c
blob: 6ab0ae7d6535db4d9bf8950eda5c4c980f65bb82 (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
/*
 * IA-64-specific support for kernel module loader.
 *
 * Copyright (C) 2003 Hewlett-Packard Co
 *	David Mosberger-Tang <davidm@hpl.hp.com>
 *
 * Loosely based on patch by Rusty Russell.
 */

/* relocs tested so far:

   DIR64LSB
   FPTR64LSB
   GPREL22
   LDXMOV
   LDXMOV
   LTOFF22
   LTOFF22X
   LTOFF22X
   LTOFF_FPTR22
   PCREL21B	(for br.call only; br.cond is not supported out of modules!)
   PCREL60B	(for brl.cond only; brl.call is not supported for modules!)
   PCREL64LSB
   SECREL32LSB
   SEGREL64LSB
 */


#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/elf.h>
#include <linux/moduleloader.h>
#include <linux/string.h>
#include <linux/vmalloc.h>

#include <asm/patch.h>
#include <asm/unaligned.h>

#define ARCH_MODULE_DEBUG 0

#if ARCH_MODULE_DEBUG
# define DEBUGP printk
# define inline
#else
# define DEBUGP(fmt , a...)
#endif

#ifdef CONFIG_ITANIUM
# define USE_BRL	0
#else
# define USE_BRL	1
#endif

#define MAX_LTOFF	((uint64_t) (1 << 22))	/* max. allowable linkage-table offset */

/* Define some relocation helper macros/types: */

#define FORMAT_SHIFT	0
#define FORMAT_BITS	3
#define FORMAT_MASK	((1 << FORMAT_BITS) - 1)
#define VALUE_SHIFT	3
#define VALUE_BITS	5
#define VALUE_MASK	((1 << VALUE_BITS) - 1)

enum reloc_target_format {
	/* direct encoded formats: */
	RF_NONE = 0,
	RF_INSN14 = 1,
	RF_INSN22 = 2,
	RF_INSN64 = 3,
	RF_32MSB = 4,
	RF_32LSB = 5,
	RF_64MSB = 6,
	RF_64LSB = 7,

	/* formats that cannot be directly decoded: */
	RF_INSN60,
	RF_INSN21B,	/* imm21 form 1 */
	RF_INSN21M,	/* imm21 form 2 */
	RF_INSN21F	/* imm21 form 3 */
};

enum reloc_value_formula {
	RV_DIRECT = 4,		/* S + A */
	RV_GPREL = 5,		/* @gprel(S + A) */
	RV_LTREL = 6,		/* @ltoff(S + A) */
	RV_PLTREL = 7,		/* @pltoff(S + A) */
	RV_FPTR = 8,		/* @fptr(S + A) */
	RV_PCREL = 9,		/* S + A - P */
	RV_LTREL_FPTR = 10,	/* @ltoff(@fptr(S + A)) */
	RV_SEGREL = 11,		/* @segrel(S + A) */
	RV_SECREL = 12,		/* @secrel(S + A) */
	RV_BDREL = 13,		/* BD + A */
	RV_LTV = 14,		/* S + A (like RV_DIRECT, except frozen at static link-time) */
	RV_PCREL2 = 15,		/* S + A - P */
	RV_SPECIAL = 16,	/* various (see below) */
	RV_RSVD17 = 17,
	RV_TPREL = 18,		/* @tprel(S + A) */
	RV_LTREL_TPREL = 19,	/* @ltoff(@tprel(S + A)) */
	RV_DTPMOD = 20,		/* @dtpmod(S + A) */
	RV_LTREL_DTPMOD = 21,	/* @ltoff(@dtpmod(S + A)) */
	RV_DTPREL = 22,		/* @dtprel(S + A) */
	RV_LTREL_DTPREL = 23,	/* @ltoff(@dtprel(S + A)) */
	RV_RSVD24 = 24,
	RV_RSVD25 = 25,
	RV_RSVD26 = 26,
	RV_RSVD27 = 27
	/* 28-31 reserved for implementation-specific purposes.  */
};

#define N(reloc)	[R_IA64_##reloc] = #reloc

static const char *reloc_name[256] = {
	N(NONE),		N(IMM14),		N(IMM22),		N(IMM64),
	N(DIR32MSB),		N(DIR32LSB),		N(DIR64MSB),		N(DIR64LSB),
	N(GPREL22),		N(GPREL64I),		N(GPREL32MSB),		N(GPREL32LSB),
	N(GPREL64MSB),		N(GPREL64LSB),		N(LTOFF22),		N(LTOFF64I),
	N(PLTOFF22),		N(PLTOFF64I),		N(PLTOFF64MSB),		N(PLTOFF64LSB),
	N(FPTR64I),		N(FPTR32MSB),		N(FPTR32LSB),		N(FPTR64MSB),
	N(FPTR64LSB),		N(PCREL60B),		N(PCREL21B),		N(PCREL21M),
	N(PCREL21F),		N(PCREL32MSB),		N(PCREL32LSB),		N(PCREL64MSB),
	N(PCREL64LSB),		N(LTOFF_FPTR22),	N(LTOFF_FPTR64I),	N(LTOFF_FPTR32MSB),
	N(LTOFF_FPTR32LSB),	N(LTOFF_FPTR64MSB),	N(LTOFF_FPTR64LSB),	N(SEGREL32MSB),
	N(SEGREL32LSB),		N(SEGREL64MSB),		N(SEGREL64LSB),		N(SECREL32MSB),
	N(SECREL32LSB),		N(SECREL64MSB),		N(SECREL64LSB),		N(REL32MSB),
	N(REL32LSB),		N(REL64MSB),		N(REL64LSB),		N(LTV32MSB),
	N(LTV32LSB),		N(LTV64MSB),		N(LTV64LSB),		N(PCREL21BI),
	N(PCREL22),		N(PCREL64I),		N(IPLTMSB),		N(IPLTLSB),
	N(COPY),		N(LTOFF22X),		N(LDXMOV),		N(TPREL14),
	N(TPREL22),		N(TPREL64I),		N(TPREL64MSB),		N(TPREL64LSB),
	N(LTOFF_TPREL22),	N(DTPMOD64MSB),		N(DTPMOD64LSB),		N(LTOFF_DTPMOD22),
	N(DTPREL14),		N(DTPREL22),		N(DTPREL64I),		N(DTPREL32MSB),
	N(DTPREL32LSB),		N(DTPREL64MSB),		N(DTPREL64LSB),		N(LTOFF_DTPREL22)
};

#undef N

/* Opaque struct for insns, to protect against derefs. */
struct insn;

static inline uint64_t
bundle (const struct insn *insn)
{
	return (uint64_t) insn & ~0xfUL;
}

static inline int
slot (const struct insn *insn)
{
	return (uint64_t) insn & 0x3;
}

static int
apply_imm64 (struct module *mod, struct insn *insn, uint64_t val)
{
	if (slot(insn) != 2) {
		printk(KERN_ERR "%s: invalid slot number %d for IMM64\n",
		       mod->name, slot(insn));
		return 0;
	}
	ia64_patch_imm64((u64) insn, val);
	return 1;
}

static int
apply_imm60 (struct module *mod, struct insn *insn, uint64_t val)
{
	if (slot(insn) != 2) {
		printk(KERN_ERR "%s: invalid slot number %d for IMM60\n",
		       mod->name, slot(insn));
		return 0;
	}
	if (val + ((uint64_t) 1 << 59) >= (1UL << 60)) {
		printk(KERN_ERR "%s: value %ld out of IMM60 range\n",
			mod->name, (long) val);
		return 0;
	}
	ia64_patch_imm60((u64) insn, val);
	return 1;
}

static int
apply_imm22 (struct module *mod, struct insn *insn, uint64_t val)
{
	if (val + (1 << 21) >= (1 << 22)) {
		printk(KERN_ERR "%s: value %li out of IMM22 range\n",
			mod->name, (long)val);
		return 0;
	}
	ia64_patch((u64) insn, 0x01fffcfe000UL, (  ((val & 0x200000UL) << 15) /* bit 21 -> 36 */
					         | ((val & 0x1f0000UL) <<  6) /* bit 16 -> 22 */
					         | ((val & 0x00ff80UL) << 20) /* bit  7 -> 27 */
					         | ((val & 0x00007fUL) << 13) /* bit  0 -> 13 */));
	return 1;
}

static int
apply_imm21b (struct module *mod, struct insn *insn, uint64_t val)
{
	if (val + (1 << 20) >= (1 << 21)) {
		printk(KERN_ERR "%s: value %li out of IMM21b range\n",
			mod->name, (long)val);
		return 0;
	}
	ia64_patch((u64) insn, 0x11ffffe000UL, (  ((val & 0x100000UL) << 16) /* bit 20 -> 36 */
					        | ((val & 0x0fffffUL) << 13) /* bit  0 -> 13 */));
	return 1;
}

#if USE_BRL

struct plt_entry {
	/* Three instruction bundles in PLT. */
 	unsigned char bundle[2][16];
};

static const struct plt_entry ia64_plt_template = {
	{
		{
			0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */
			0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /*	     movl gp=TARGET_GP */
			0x00, 0x00, 0x00, 0x60
		},
		{
			0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */
			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*	     brl.many gp=TARGET_GP */
			0x08, 0x00, 0x00, 0xc0
		}
	}
};

static int
patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp)
{
	if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_gp)
	    && apply_imm60(mod, (struct insn *) (plt->bundle[1] + 2),
			   (target_ip - (int64_t) plt->bundle[1]) / 16))
		return 1;
	return 0;
}

unsigned long
plt_target (struct plt_entry *plt)
{
	uint64_t b0, b1, *b = (uint64_t *) plt->bundle[1];
	long off;

	b0 = b[0]; b1 = b[1];
	off = (  ((b1 & 0x00fffff000000000UL) >> 36)		/* imm20b -> bit 0 */
	       | ((b0 >> 48) << 20) | ((b1 & 0x7fffffUL) << 36)	/* imm39 -> bit 20 */
	       | ((b1 & 0x0800000000000000UL) << 0));		/* i -> bit 59 */
	return (long) plt->bundle[1] + 16*off;
}

#else /* !USE_BRL */

struct plt_entry {
	/* Three instruction bundles in PLT. */
 	unsigned char bundle[3][16];
};

static const struct plt_entry ia64_plt_template = {
	{
		{
			0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */
			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /*	     movl r16=TARGET_IP */
			0x02, 0x00, 0x00, 0x60
		},
		{
			0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */
			0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /*	     movl gp=TARGET_GP */
			0x00, 0x00, 0x00, 0x60
		},
		{
			0x11, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MIB] nop.m 0 */
			0x60, 0x80, 0x04, 0x80, 0x03, 0x00, /*	     mov b6=r16 */
			0x60, 0x00, 0x80, 0x00		    /*	     br.few b6 */
		}
	}
};

static int
patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp)
{
	if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_ip)
	    && apply_imm64(mod, (struct insn *) (plt->bundle[1] + 2), target_gp))
		return 1;
	return 0;
}

unsigned long
plt_target (struct plt_entry *plt)
{
	uint64_t b0, b1, *b = (uint64_t *) plt->bundle[0];

	b0 = b[0]; b1 = b[1];
	return (  ((b1 & 0x000007f000000000) >> 36)		/* imm7b -> bit 0 */
		| ((b1 & 0x07fc000000000000) >> 43)		/* imm9d -> bit 7 */
		| ((b1 & 0x0003e00000000000) >> 29)		/* imm5c -> bit 16 */
		| ((b1 & 0x0000100000000000) >> 23)		/* ic -> bit 21 */
		| ((b0 >> 46) << 22) | ((b1 & 0x7fffff) << 40)	/* imm41 -> bit 22 */
		| ((b1 & 0x0800000000000000) <<  4));		/* i -> bit 63 */
}

#endif /* !USE_BRL */

void
module_arch_freeing_init (struct module *mod)
{
	if (mod->arch.init_unw_table) {
		unw_remove_unwind_table(mod->arch.init_unw_table);
		mod->arch.init_unw_table = NULL;
	}
}

/* Have we already seen one of these relocations? */
/* FIXME: we could look in other sections, too --RR */
static int
duplicate_reloc (const Elf64_Rela *rela, unsigned int num)
{
	unsigned int i;

	for (i = 0; i < num; i++) {
		if (rela[i].r_info == rela[num].r_info && rela[i].r_addend == rela[num].r_addend)
			return 1;
	}
	return 0;
}

/* Count how many GOT entries we may need */
static unsigned int
count_gots (const Elf64_Rela *rela, unsigned int num)
{
	unsigned int i, ret = 0;

	/* Sure, this is order(n^2), but it's usually short, and not
           time critical */
	for (i = 0; i < num; i++) {
		switch (ELF64_R_TYPE(rela[i].r_info)) {
		      case R_IA64_LTOFF22:
		      case R_IA64_LTOFF22X:
		      case R_IA64_LTOFF64I:
		      case R_IA64_LTOFF_FPTR22:
		      case R_IA64_LTOFF_FPTR64I:
		      case R_IA64_LTOFF_FPTR32MSB:
		      case R_IA64_LTOFF_FPTR32LSB:
		      case R_IA64_LTOFF_FPTR64MSB:
		      case R_IA64_LTOFF_FPTR64LSB:
			if (!duplicate_reloc(rela, i))
				ret++;
			break;
		}
	}
	return ret;
}

/* Count how many PLT entries we may need */
static unsigned int
count_plts (const Elf64_Rela *rela, unsigned int num)
{
	unsigned int i, ret = 0;

	/* Sure, this is order(n^2), but it's usually short, and not
           time critical */
	for (i = 0; i < num; i++) {
		switch (ELF64_R_TYPE(rela[i].r_info)) {
		      case R_IA64_PCREL21B:
		      case R_IA64_PLTOFF22:
		      case R_IA64_PLTOFF64I:
		      case R_IA64_PLTOFF64MSB:
		      case R_IA64_PLTOFF64LSB:
		      case R_IA64_IPLTMSB:
		      case R_IA64_IPLTLSB:
			if (!duplicate_reloc(rela, i))
				ret++;
			break;
		}
	}
	return ret;
}

/* We need to create an function-descriptors for any internal function
   which is referenced. */
static unsigned int
count_fdescs (const Elf64_Rela *rela, unsigned int num)
{
	unsigned int i, ret = 0;

	/* Sure, this is order(n^2), but it's usually short, and not time critical.  */
	for (i = 0; i < num; i++) {
		switch (ELF64_R_TYPE(rela[i].r_info)) {
		      case R_IA64_FPTR64I:
		      case R_IA64_FPTR32LSB:
		      case R_IA64_FPTR32MSB:
		      case R_IA64_FPTR64LSB:
		      case R_IA64_FPTR64MSB:
		      case R_IA64_LTOFF_FPTR22:
		      case R_IA64_LTOFF_FPTR32LSB:
		      case R_IA64_LTOFF_FPTR32MSB:
		      case R_IA64_LTOFF_FPTR64I:
		      case R_IA64_LTOFF_FPTR64LSB:
		      case R_IA64_LTOFF_FPTR64MSB:
		      case R_IA64_IPLTMSB:
		      case R_IA64_IPLTLSB:
			/*
			 * Jumps to static functions sometimes go straight to their
			 * offset.  Of course, that may not be possible if the jump is
			 * from init -> core or vice. versa, so we need to generate an
			 * FDESC (and PLT etc) for that.
			 */
		      case R_IA64_PCREL21B:
			if (!duplicate_reloc(rela, i))
				ret++;
			break;
		}
	}
	return ret;
}

int
module_frob_arch_sections (Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings,
			   struct module *mod)
{
	unsigned long core_plts = 0, init_plts = 0, gots = 0, fdescs = 0;
	Elf64_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum;

	/*
	 * To store the PLTs and function-descriptors, we expand the .text section for
	 * core module-code and the .init.text section for initialization code.
	 */
	for (s = sechdrs; s < sechdrs_end; ++s)
		if (strcmp(".core.plt", secstrings + s->sh_name) == 0)
			mod->arch.core_plt = s;
		else if (strcmp(".init.plt", secstrings + s->sh_name) == 0)
			mod->arch.init_plt = s;
		else if (strcmp(".got", secstrings + s->sh_name) == 0)
			mod->arch.got = s;
		else if (strcmp(".opd", secstrings + s->sh_name) == 0)
			mod->arch.opd = s;
		else if (strcmp(".IA_64.unwind", secstrings + s->sh_name) == 0)
			mod->arch.unwind = s;

	if (!mod->arch.core_plt || !mod->arch.init_plt || !mod->arch.got || !mod->arch.opd) {
		printk(KERN_ERR "%s: sections missing\n", mod->name);
		return -ENOEXEC;
	}

	/* GOT and PLTs can occur in any relocated section... */
	for (s = sechdrs + 1; s < sechdrs_end; ++s) {
		const Elf64_Rela *rels = (void *)ehdr + s->sh_offset;
		unsigned long numrels = s->sh_size/sizeof(Elf64_Rela);

		if (s->sh_type != SHT_RELA)
			continue;

		gots += count_gots(rels, numrels);
		fdescs += count_fdescs(rels, numrels);
		if (strstr(secstrings + s->sh_name, ".init"))
			init_plts += count_plts(rels, numrels);
		else
			core_plts += count_plts(rels, numrels);
	}

	mod->arch.core_plt->sh_type = SHT_NOBITS;
	mod->arch.core_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
	mod->arch.core_plt->sh_addralign = 16;
	mod->arch.core_plt->sh_size = core_plts * sizeof(struct plt_entry);
	mod->arch.init_plt->sh_type = SHT_NOBITS;
	mod->arch.init_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
	mod->arch.init_plt->sh_addralign = 16;
	mod->arch.init_plt->sh_size = init_plts * sizeof(struct plt_entry);
	mod->arch.got->sh_type = SHT_NOBITS;
	mod->arch.got->sh_flags = ARCH_SHF_SMALL | SHF_ALLOC;
	mod->arch.got->sh_addralign = 8;
	mod->arch.got->sh_size = gots * sizeof(struct got_entry);
	mod->arch.opd->sh_type = SHT_NOBITS;
	mod->arch.opd->sh_flags = SHF_ALLOC;
	mod->arch.opd->sh_addralign = 8;
	mod->arch.opd->sh_size = fdescs * sizeof(struct fdesc);
	DEBUGP("%s: core.plt=%lx, init.plt=%lx, got=%lx, fdesc=%lx\n",
	       __func__, mod->arch.core_plt->sh_size, mod->arch.init_plt->sh_size,
	       mod->arch.got->sh_size, mod->arch.opd->sh_size);
	return 0;
}

static inline int
in_init (const struct module *mod, uint64_t addr)
{
	return addr - (uint64_t) mod->init_layout.base < mod->init_layout.size;
}

static inline int
in_core (const struct module *mod, uint64_t addr)
{
	return addr - (uint64_t) mod->core_layout.base < mod->core_layout.size;
}

static inline int
is_internal (const struct module *mod, uint64_t value)
{
	return in_init(mod, value) || in_core(mod, value);
}

/*
 * Get gp-relative offset for the linkage-table entry of VALUE.
 */
static uint64_t
get_ltoff (struct module *mod, uint64_t value, int *okp)
{
	struct got_entry *got, *e;

	if (!*okp)
		return 0;

	got = (void *) mod->arch.got->sh_addr;
	for (e = got; e < got + mod->arch.next_got_entry; ++e)
		if (e->val == value)
			goto found;

	/* Not enough GOT entries? */
	BUG_ON(e >= (struct got_entry *) (mod->arch.got->sh_addr + mod->arch.got->sh_size));

	e->val = value;
	++mod->arch.next_got_entry;
  found:
	return (uint64_t) e - mod->arch.gp;
}

static inline int
gp_addressable (struct module *mod, uint64_t value)
{
	return value - mod->arch.gp + MAX_LTOFF/2 < MAX_LTOFF;
}

/* Get PC-relative PLT entry for this value.  Returns 0 on failure. */
static uint64_t
get_plt (struct module *mod, const struct insn *insn, uint64_t value, int *okp)
{
	struct plt_entry *plt, *plt_end;
	uint64_t target_ip, target_gp;

	if (!*okp)
		return 0;

	if (in_init(mod, (uint64_t) insn)) {
		plt = (void *) mod->arch.init_plt->sh_addr;
		plt_end = (void *) plt + mod->arch.init_plt->sh_size;
	} else {
		plt = (void *) mod->arch.core_plt->sh_addr;
		plt_end = (void *) plt + mod->arch.core_plt->sh_size;
	}

	/* "value" is a pointer to a function-descriptor; fetch the target ip/gp from it: */
	target_ip = ((uint64_t *) value)[0];
	target_gp = ((uint64_t *) value)[1];

	/* Look for existing PLT entry. */
	while (plt->bundle[0][0]) {
		if (plt_target(plt) == target_ip)
			goto found;
		if (++plt >= plt_end)
			BUG();
	}
	*plt = ia64_plt_template;
	if (!patch_plt(mod, plt, target_ip, target_gp)) {
		*okp = 0;
		return 0;
	}
#if ARCH_MODULE_DEBUG
	if (plt_target(plt) != target_ip) {
		printk("%s: mistargeted PLT: wanted %lx, got %lx\n",
		       __func__, target_ip, plt_target(plt));
		*okp = 0;
		return 0;
	}
#endif
  found:
	return (uint64_t) plt;
}

/* Get function descriptor for VALUE. */
static uint64_t
get_fdesc (struct module *mod, uint64_t value, int *okp)
{
	struct fdesc *fdesc = (void *) mod->arch.opd->sh_addr;

	if (!*okp)
		return 0;

	if (!value) {
		printk(KERN_ERR "%s: fdesc for zero requested!\n", mod->name);
		return 0;
	}

	if (!is_internal(mod, value))
		/*
		 * If it's not a module-local entry-point, "value" already points to a
		 * function-descriptor.
		 */
		return value;

	/* Look for existing function descriptor. */
	while (fdesc->ip) {
		if (fdesc->ip == value)
			return (uint64_t)fdesc;
		if ((uint64_t) ++fdesc >= mod->arch.opd->sh_addr + mod->arch.opd->sh_size)
			BUG();
	}

	/* Create new one */
	fdesc->ip = value;
	fdesc->gp = mod->arch.gp;
	return (uint64_t) fdesc;
}

static inline int
do_reloc (struct module *mod, uint8_t r_type, Elf64_Sym *sym, uint64_t addend,
	  Elf64_Shdr *sec, void *location)
{
	enum reloc_target_format format = (r_type >> FORMAT_SHIFT) & FORMAT_MASK;
	enum reloc_value_formula formula = (r_type >> VALUE_SHIFT) & VALUE_MASK;
	uint64_t val;
	int ok = 1;

	val = sym->st_value + addend;

	switch (formula) {
	      case RV_SEGREL:	/* segment base is arbitrarily chosen to be 0 for kernel modules */
	      case RV_DIRECT:
		break;

	      case RV_GPREL:	  val -= mod->arch.gp; break;
	      case RV_LTREL:	  val = get_ltoff(mod, val, &ok); break;
	      case RV_PLTREL:	  val = get_plt(mod, location, val, &ok); break;
	      case RV_FPTR:	  val = get_fdesc(mod, val, &ok); break;
	      case RV_SECREL:	  val -= sec->sh_addr; break;
	      case RV_LTREL_FPTR: val = get_ltoff(mod, get_fdesc(mod, val, &ok), &ok); break;

	      case RV_PCREL:
		switch (r_type) {
		      case R_IA64_PCREL21B:
			if ((in_init(mod, val) && in_core(mod, (uint64_t)location)) ||
			    (in_core(mod, val) && in_init(mod, (uint64_t)location))) {
				/*
				 * Init section may have been allocated far away from core,
				 * if the branch won't reach, then allocate a plt for it.
				 */
				uint64_t delta = ((int64_t)val - (int64_t)location) / 16;
				if (delta + (1 << 20) >= (1 << 21)) {
					val = get_fdesc(mod, val, &ok);
					val = get_plt(mod, location, val, &ok);
				}
			} else if (!is_internal(mod, val))
				val = get_plt(mod, location, val, &ok);
			/* FALL THROUGH */
		      default:
			val -= bundle(location);
			break;

		      case R_IA64_PCREL32MSB:
		      case R_IA64_PCREL32LSB:
		      case R_IA64_PCREL64MSB:
		      case R_IA64_PCREL64LSB:
			val -= (uint64_t) location;
			break;

		}
		switch (r_type) {
		      case R_IA64_PCREL60B: format = RF_INSN60; break;
		      case R_IA64_PCREL21B: format = RF_INSN21B; break;
		      case R_IA64_PCREL21M: format = RF_INSN21M; break;
		      case R_IA64_PCREL21F: format = RF_INSN21F; break;
		      default: break;
		}
		break;

	      case RV_BDREL:
		val -= (uint64_t) (in_init(mod, val) ? mod->init_layout.base : mod->core_layout.base);
		break;

	      case RV_LTV:
		/* can link-time value relocs happen here?  */
		BUG();
		break;

	      case RV_PCREL2:
		if (r_type == R_IA64_PCREL21BI) {
			if (!is_internal(mod, val)) {
				printk(KERN_ERR "%s: %s reloc against "
					"non-local symbol (%lx)\n", __func__,
					reloc_name[r_type], (unsigned long)val);
				return -ENOEXEC;
			}
			format = RF_INSN21B;
		}
		val -= bundle(location);
		break;

	      case RV_SPECIAL:
		switch (r_type) {
		      case R_IA64_IPLTMSB:
		      case R_IA64_IPLTLSB:
			val = get_fdesc(mod, get_plt(mod, location, val, &ok), &ok);
			format = RF_64LSB;
			if (r_type == R_IA64_IPLTMSB)
				format = RF_64MSB;
			break;

		      case R_IA64_SUB:
			val = addend - sym->st_value;
			format = RF_INSN64;
			break;

		      case R_IA64_LTOFF22X:
			if (gp_addressable(mod, val))
				val -= mod->arch.gp;
			else
				val = get_ltoff(mod, val, &ok);
			format = RF_INSN22;
			break;

		      case R_IA64_LDXMOV:
			if (gp_addressable(mod, val)) {
				/* turn "ld8" into "mov": */
				DEBUGP("%s: patching ld8 at %p to mov\n", __func__, location);
				ia64_patch((u64) location, 0x1fff80fe000UL, 0x10000000000UL);
			}
			return 0;

		      default:
			if (reloc_name[r_type])
				printk(KERN_ERR "%s: special reloc %s not supported",
				       mod->name, reloc_name[r_type]);
			else
				printk(KERN_ERR "%s: unknown special reloc %x\n",
				       mod->name, r_type);
			return -ENOEXEC;
		}
		break;

	      case RV_TPREL:
	      case RV_LTREL_TPREL:
	      case RV_DTPMOD:
	      case RV_LTREL_DTPMOD:
	      case RV_DTPREL:
	      case RV_LTREL_DTPREL:
		printk(KERN_ERR "%s: %s reloc not supported\n",
		       mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?");
		return -ENOEXEC;

	      default:
		printk(KERN_ERR "%s: unknown reloc %x\n", mod->name, r_type);
		return -ENOEXEC;
	}

	if (!ok)
		return -ENOEXEC;

	DEBUGP("%s: [%p]<-%016lx = %s(%lx)\n", __func__, location, val,
	       reloc_name[r_type] ? reloc_name[r_type] : "?", sym->st_value + addend);

	switch (format) {
	      case RF_INSN21B:	ok = apply_imm21b(mod, location, (int64_t) val / 16); break;
	      case RF_INSN22:	ok = apply_imm22(mod, location, val); break;
	      case RF_INSN64:	ok = apply_imm64(mod, location, val); break;
	      case RF_INSN60:	ok = apply_imm60(mod, location, (int64_t) val / 16); break;
	      case RF_32LSB:	put_unaligned(val, (uint32_t *) location); break;
	      case RF_64LSB:	put_unaligned(val, (uint64_t *) location); break;
	      case RF_32MSB:	/* ia64 Linux is little-endian... */
	      case RF_64MSB:	/* ia64 Linux is little-endian... */
	      case RF_INSN14:	/* must be within-module, i.e., resolved by "ld -r" */
	      case RF_INSN21M:	/* must be within-module, i.e., resolved by "ld -r" */
	      case RF_INSN21F:	/* must be within-module, i.e., resolved by "ld -r" */
		printk(KERN_ERR "%s: format %u needed by %s reloc is not supported\n",
		       mod->name, format, reloc_name[r_type] ? reloc_name[r_type] : "?");
		return -ENOEXEC;

	      default:
		printk(KERN_ERR "%s: relocation %s resulted in unknown format %u\n",
		       mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?", format);
		return -ENOEXEC;
	}
	return ok ? 0 : -ENOEXEC;
}

int
apply_relocate_add (Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex,
		    unsigned int relsec, struct module *mod)
{
	unsigned int i, n = sechdrs[relsec].sh_size / sizeof(Elf64_Rela);
	Elf64_Rela *rela = (void *) sechdrs[relsec].sh_addr;
	Elf64_Shdr *target_sec;
	int ret;

	DEBUGP("%s: applying section %u (%u relocs) to %u\n", __func__,
	       relsec, n, sechdrs[relsec].sh_info);

	target_sec = sechdrs + sechdrs[relsec].sh_info;

	if (target_sec->sh_entsize == ~0UL)
		/*
		 * If target section wasn't allocated, we don't need to relocate it.
		 * Happens, e.g., for debug sections.
		 */
		return 0;

	if (!mod->arch.gp) {
		/*
		 * XXX Should have an arch-hook for running this after final section
		 *     addresses have been selected...
		 */
		uint64_t gp;
		if (mod->core_layout.size > MAX_LTOFF)
			/*
			 * This takes advantage of fact that SHF_ARCH_SMALL gets allocated
			 * at the end of the module.
			 */
			gp = mod->core_layout.size - MAX_LTOFF / 2;
		else
			gp = mod->core_layout.size / 2;
		gp = (uint64_t) mod->core_layout.base + ((gp + 7) & -8);
		mod->arch.gp = gp;
		DEBUGP("%s: placing gp at 0x%lx\n", __func__, gp);
	}

	for (i = 0; i < n; i++) {
		ret = do_reloc(mod, ELF64_R_TYPE(rela[i].r_info),
			       ((Elf64_Sym *) sechdrs[symindex].sh_addr
				+ ELF64_R_SYM(rela[i].r_info)),
			       rela[i].r_addend, target_sec,
			       (void *) target_sec->sh_addr + rela[i].r_offset);
		if (ret < 0)
			return ret;
	}
	return 0;
}

/*
 * Modules contain a single unwind table which covers both the core and the init text
 * sections but since the two are not contiguous, we need to split this table up such that
 * we can register (and unregister) each "segment" separately.  Fortunately, this sounds
 * more complicated than it really is.
 */
static void
register_unwind_table (struct module *mod)
{
	struct unw_table_entry *start = (void *) mod->arch.unwind->sh_addr;
	struct unw_table_entry *end = start + mod->arch.unwind->sh_size / sizeof (*start);
	struct unw_table_entry tmp, *e1, *e2, *core, *init;
	unsigned long num_init = 0, num_core = 0;

	/* First, count how many init and core unwind-table entries there are.  */
	for (e1 = start; e1 < end; ++e1)
		if (in_init(mod, e1->start_offset))
			++num_init;
		else
			++num_core;
	/*
	 * Second, sort the table such that all unwind-table entries for the init and core
	 * text sections are nicely separated.  We do this with a stupid bubble sort
	 * (unwind tables don't get ridiculously huge).
	 */
	for (e1 = start; e1 < end; ++e1) {
		for (e2 = e1 + 1; e2 < end; ++e2) {
			if (e2->start_offset < e1->start_offset) {
				tmp = *e1;
				*e1 = *e2;
				*e2 = tmp;
			}
		}
	}
	/*
	 * Third, locate the init and core segments in the unwind table:
	 */
	if (in_init(mod, start->start_offset)) {
		init = start;
		core = start + num_init;
	} else {
		core = start;
		init = start + num_core;
	}

	DEBUGP("%s: name=%s, gp=%lx, num_init=%lu, num_core=%lu\n", __func__,
	       mod->name, mod->arch.gp, num_init, num_core);

	/*
	 * Fourth, register both tables (if not empty).
	 */
	if (num_core > 0) {
		mod->arch.core_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp,
								core, core + num_core);
		DEBUGP("%s:  core: handle=%p [%p-%p)\n", __func__,
		       mod->arch.core_unw_table, core, core + num_core);
	}
	if (num_init > 0) {
		mod->arch.init_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp,
								init, init + num_init);
		DEBUGP("%s:  init: handle=%p [%p-%p)\n", __func__,
		       mod->arch.init_unw_table, init, init + num_init);
	}
}

int
module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod)
{
	DEBUGP("%s: init: entry=%p\n", __func__, mod->init);
	if (mod->arch.unwind)
		register_unwind_table(mod);
	return 0;
}

void
module_arch_cleanup (struct module *mod)
{
	if (mod->arch.init_unw_table)
		unw_remove_unwind_table(mod->arch.init_unw_table);
	if (mod->arch.core_unw_table)
		unw_remove_unwind_table(mod->arch.core_unw_table);
}

Privacy Policy