summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/signal_64.c
blob: ef518535d436878cdc869725789bdaf048f5d3c5 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  PowerPC version 
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Derived from "arch/i386/kernel/signal.c"
 *    Copyright (C) 1991, 1992 Linus Torvalds
 *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/elf.h>
#include <linux/ptrace.h>
#include <linux/ratelimit.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>

#include <asm/sigcontext.h>
#include <asm/ucontext.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/cacheflush.h>
#include <asm/syscalls.h>
#include <asm/vdso.h>
#include <asm/switch_to.h>
#include <asm/tm.h>
#include <asm/asm-prototypes.h>

#include "signal.h"


#define GP_REGS_SIZE	min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
#define FP_REGS_SIZE	sizeof(elf_fpregset_t)

#define TRAMP_TRACEBACK	4
#define TRAMP_SIZE	7

/*
 * When we have signals to deliver, we set up on the user stack,
 * going down from the original stack pointer:
 *	1) a rt_sigframe struct which contains the ucontext	
 *	2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
 *	   frame for the signal handler.
 */

struct rt_sigframe {
	/* sys_rt_sigreturn requires the ucontext be the first field */
	struct ucontext uc;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	struct ucontext uc_transact;
#endif
	unsigned long _unused[2];
	unsigned int tramp[TRAMP_SIZE];
	struct siginfo __user *pinfo;
	void __user *puc;
	struct siginfo info;
	/* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
	char abigap[USER_REDZONE_SIZE];
} __attribute__ ((aligned (16)));

/*
 * This computes a quad word aligned pointer inside the vmx_reserve array
 * element. For historical reasons sigcontext might not be quad word aligned,
 * but the location we write the VMX regs to must be. See the comment in
 * sigcontext for more detail.
 */
#ifdef CONFIG_ALTIVEC
static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
{
	return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
}
#endif

static void prepare_setup_sigcontext(struct task_struct *tsk)
{
#ifdef CONFIG_ALTIVEC
	/* save altivec registers */
	if (tsk->thread.used_vr)
		flush_altivec_to_thread(tsk);
	if (cpu_has_feature(CPU_FTR_ALTIVEC))
		tsk->thread.vrsave = mfspr(SPRN_VRSAVE);
#endif /* CONFIG_ALTIVEC */

	flush_fp_to_thread(tsk);

#ifdef CONFIG_VSX
	if (tsk->thread.used_vsr)
		flush_vsx_to_thread(tsk);
#endif /* CONFIG_VSX */
}

/*
 * Set up the sigcontext for the signal frame.
 */

#define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\
do {											\
	if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region))\
		goto label;								\
} while (0)
static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc,
					struct task_struct *tsk, int signr, sigset_t *set,
					unsigned long handler, int ctx_has_vsx_region)
{
	/* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
	 * process never used altivec yet (MSR_VEC is zero in pt_regs of
	 * the context). This is very important because we must ensure we
	 * don't lose the VRSAVE content that may have been set prior to
	 * the process doing its first vector operation
	 * Userland shall check AT_HWCAP to know whether it can rely on the
	 * v_regs pointer or not
	 */
#ifdef CONFIG_ALTIVEC
	elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
#endif
	struct pt_regs *regs = tsk->thread.regs;
	unsigned long msr = regs->msr;
	/* Force usr to alway see softe as 1 (interrupts enabled) */
	unsigned long softe = 0x1;

	BUG_ON(tsk != current);

#ifdef CONFIG_ALTIVEC
	unsafe_put_user(v_regs, &sc->v_regs, efault_out);

	/* save altivec registers */
	if (tsk->thread.used_vr) {
		/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
		unsafe_copy_to_user(v_regs, &tsk->thread.vr_state,
				    33 * sizeof(vector128), efault_out);
		/* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
		 * contains valid data.
		 */
		msr |= MSR_VEC;
	}
	/* We always copy to/from vrsave, it's 0 if we don't have or don't
	 * use altivec.
	 */
	unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
#else /* CONFIG_ALTIVEC */
	unsafe_put_user(0, &sc->v_regs, efault_out);
#endif /* CONFIG_ALTIVEC */
	/* copy fpr regs and fpscr */
	unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out);

	/*
	 * Clear the MSR VSX bit to indicate there is no valid state attached
	 * to this context, except in the specific case below where we set it.
	 */
	msr &= ~MSR_VSX;
#ifdef CONFIG_VSX
	/*
	 * Copy VSX low doubleword to local buffer for formatting,
	 * then out to userspace.  Update v_regs to point after the
	 * VMX data.
	 */
	if (tsk->thread.used_vsr && ctx_has_vsx_region) {
		v_regs += ELF_NVRREG;
		unsafe_copy_vsx_to_user(v_regs, tsk, efault_out);
		/* set MSR_VSX in the MSR value in the frame to
		 * indicate that sc->vs_reg) contains valid data.
		 */
		msr |= MSR_VSX;
	}
#endif /* CONFIG_VSX */
	unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out);
	unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out);
	unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out);
	unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out);
	unsafe_put_user(signr, &sc->signal, efault_out);
	unsafe_put_user(handler, &sc->handler, efault_out);
	if (set != NULL)
		unsafe_put_user(set->sig[0], &sc->oldmask, efault_out);

	return 0;

efault_out:
	return -EFAULT;
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/*
 * As above, but Transactional Memory is in use, so deliver sigcontexts
 * containing checkpointed and transactional register states.
 *
 * To do this, we treclaim (done before entering here) to gather both sets of
 * registers and set up the 'normal' sigcontext registers with rolled-back
 * register values such that a simple signal handler sees a correct
 * checkpointed register state.  If interested, a TM-aware sighandler can
 * examine the transactional registers in the 2nd sigcontext to determine the
 * real origin of the signal.
 */
static long setup_tm_sigcontexts(struct sigcontext __user *sc,
				 struct sigcontext __user *tm_sc,
				 struct task_struct *tsk,
				 int signr, sigset_t *set, unsigned long handler,
				 unsigned long msr)
{
	/* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
	 * process never used altivec yet (MSR_VEC is zero in pt_regs of
	 * the context). This is very important because we must ensure we
	 * don't lose the VRSAVE content that may have been set prior to
	 * the process doing its first vector operation
	 * Userland shall check AT_HWCAP to know wether it can rely on the
	 * v_regs pointer or not.
	 */
#ifdef CONFIG_ALTIVEC
	elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
	elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
#endif
	struct pt_regs *regs = tsk->thread.regs;
	long err = 0;

	BUG_ON(tsk != current);

	BUG_ON(!MSR_TM_ACTIVE(msr));

	WARN_ON(tm_suspend_disabled);

	/* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as
	 * it contains the correct FP, VEC, VSX state after we treclaimed
	 * the transaction and giveup_all() was called on reclaiming.
	 */
	msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX);

#ifdef CONFIG_ALTIVEC
	err |= __put_user(v_regs, &sc->v_regs);
	err |= __put_user(tm_v_regs, &tm_sc->v_regs);

	/* save altivec registers */
	if (tsk->thread.used_vr) {
		/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
		err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state,
				      33 * sizeof(vector128));
		/* If VEC was enabled there are transactional VRs valid too,
		 * else they're a copy of the checkpointed VRs.
		 */
		if (msr & MSR_VEC)
			err |= __copy_to_user(tm_v_regs,
					      &tsk->thread.vr_state,
					      33 * sizeof(vector128));
		else
			err |= __copy_to_user(tm_v_regs,
					      &tsk->thread.ckvr_state,
					      33 * sizeof(vector128));

		/* set MSR_VEC in the MSR value in the frame to indicate
		 * that sc->v_reg contains valid data.
		 */
		msr |= MSR_VEC;
	}
	/* We always copy to/from vrsave, it's 0 if we don't have or don't
	 * use altivec.
	 */
	if (cpu_has_feature(CPU_FTR_ALTIVEC))
		tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE);
	err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]);
	if (msr & MSR_VEC)
		err |= __put_user(tsk->thread.vrsave,
				  (u32 __user *)&tm_v_regs[33]);
	else
		err |= __put_user(tsk->thread.ckvrsave,
				  (u32 __user *)&tm_v_regs[33]);

#else /* CONFIG_ALTIVEC */
	err |= __put_user(0, &sc->v_regs);
	err |= __put_user(0, &tm_sc->v_regs);
#endif /* CONFIG_ALTIVEC */

	/* copy fpr regs and fpscr */
	err |= copy_ckfpr_to_user(&sc->fp_regs, tsk);
	if (msr & MSR_FP)
		err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk);
	else
		err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk);

#ifdef CONFIG_VSX
	/*
	 * Copy VSX low doubleword to local buffer for formatting,
	 * then out to userspace.  Update v_regs to point after the
	 * VMX data.
	 */
	if (tsk->thread.used_vsr) {
		v_regs += ELF_NVRREG;
		tm_v_regs += ELF_NVRREG;

		err |= copy_ckvsx_to_user(v_regs, tsk);

		if (msr & MSR_VSX)
			err |= copy_vsx_to_user(tm_v_regs, tsk);
		else
			err |= copy_ckvsx_to_user(tm_v_regs, tsk);

		/* set MSR_VSX in the MSR value in the frame to
		 * indicate that sc->vs_reg) contains valid data.
		 */
		msr |= MSR_VSX;
	}
#endif /* CONFIG_VSX */

	err |= __put_user(&sc->gp_regs, &sc->regs);
	err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
	err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
	err |= __copy_to_user(&sc->gp_regs,
			      &tsk->thread.ckpt_regs, GP_REGS_SIZE);
	err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
	err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
	err |= __put_user(signr, &sc->signal);
	err |= __put_user(handler, &sc->handler);
	if (set != NULL)
		err |=  __put_user(set->sig[0], &sc->oldmask);

	return err;
}
#endif

/*
 * Restore the sigcontext from the signal frame.
 */
#define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do {	\
	if (__unsafe_restore_sigcontext(tsk, set, sig, sc))		\
		goto label;						\
} while (0)
static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set,
						int sig, struct sigcontext __user *sc)
{
#ifdef CONFIG_ALTIVEC
	elf_vrreg_t __user *v_regs;
#endif
	unsigned long save_r13 = 0;
	unsigned long msr;
	struct pt_regs *regs = tsk->thread.regs;
#ifdef CONFIG_VSX
	int i;
#endif

	BUG_ON(tsk != current);

	/* If this is not a signal return, we preserve the TLS in r13 */
	if (!sig)
		save_r13 = regs->gpr[13];

	/* copy the GPRs */
	unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out);
	unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out);
	/* get MSR separately, transfer the LE bit if doing signal return */
	unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out);
	if (sig)
		regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE));
	unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out);
	unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out);
	unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out);
	unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out);
	unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out);
	/* Don't allow userspace to set SOFTE */
	set_trap_norestart(regs);
	unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out);
	unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out);
	unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out);

	if (!sig)
		regs->gpr[13] = save_r13;
	if (set != NULL)
		unsafe_get_user(set->sig[0], &sc->oldmask, efault_out);

	/*
	 * Force reload of FP/VEC.
	 * This has to be done before copying stuff into tsk->thread.fpr/vr
	 * for the reasons explained in the previous comment.
	 */
	regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX));

#ifdef CONFIG_ALTIVEC
	unsafe_get_user(v_regs, &sc->v_regs, efault_out);
	if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
		return -EFAULT;
	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
	if (v_regs != NULL && (msr & MSR_VEC) != 0) {
		unsafe_copy_from_user(&tsk->thread.vr_state, v_regs,
				      33 * sizeof(vector128), efault_out);
		tsk->thread.used_vr = true;
	} else if (tsk->thread.used_vr) {
		memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
	}
	/* Always get VRSAVE back */
	if (v_regs != NULL)
		unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
	else
		tsk->thread.vrsave = 0;
	if (cpu_has_feature(CPU_FTR_ALTIVEC))
		mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
#endif /* CONFIG_ALTIVEC */
	/* restore floating point */
	unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out);
#ifdef CONFIG_VSX
	/*
	 * Get additional VSX data. Update v_regs to point after the
	 * VMX data.  Copy VSX low doubleword from userspace to local
	 * buffer for formatting, then into the taskstruct.
	 */
	v_regs += ELF_NVRREG;
	if ((msr & MSR_VSX) != 0) {
		unsafe_copy_vsx_from_user(tsk, v_regs, efault_out);
		tsk->thread.used_vsr = true;
	} else {
		for (i = 0; i < 32 ; i++)
			tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
	}
#endif
	return 0;

efault_out:
	return -EFAULT;
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
/*
 * Restore the two sigcontexts from the frame of a transactional processes.
 */

static long restore_tm_sigcontexts(struct task_struct *tsk,
				   struct sigcontext __user *sc,
				   struct sigcontext __user *tm_sc)
{
#ifdef CONFIG_ALTIVEC
	elf_vrreg_t __user *v_regs, *tm_v_regs;
#endif
	unsigned long err = 0;
	unsigned long msr;
	struct pt_regs *regs = tsk->thread.regs;
#ifdef CONFIG_VSX
	int i;
#endif

	BUG_ON(tsk != current);

	if (tm_suspend_disabled)
		return -EINVAL;

	/* copy the GPRs */
	err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
	err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs,
				sizeof(regs->gpr));

	/*
	 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
	 * TEXASR was set by the signal delivery reclaim, as was TFIAR.
	 * Users doing anything abhorrent like thread-switching w/ signals for
	 * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
	 * For the case of getting a signal and simply returning from it,
	 * we don't need to re-copy them here.
	 */
	err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
	err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);

	/* get MSR separately, transfer the LE bit if doing signal return */
	err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
	/* Don't allow reserved mode. */
	if (MSR_TM_RESV(msr))
		return -EINVAL;

	/* pull in MSR LE from user context */
	regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE));

	/* The following non-GPR non-FPR non-VR state is also checkpointed: */
	err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
	err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
	err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
	err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
	err |= __get_user(tsk->thread.ckpt_regs.ctr,
			  &sc->gp_regs[PT_CTR]);
	err |= __get_user(tsk->thread.ckpt_regs.link,
			  &sc->gp_regs[PT_LNK]);
	err |= __get_user(tsk->thread.ckpt_regs.xer,
			  &sc->gp_regs[PT_XER]);
	err |= __get_user(tsk->thread.ckpt_regs.ccr,
			  &sc->gp_regs[PT_CCR]);
	/* Don't allow userspace to set SOFTE */
	set_trap_norestart(regs);
	/* These regs are not checkpointed; they can go in 'regs'. */
	err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
	err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
	err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);

	/*
	 * Force reload of FP/VEC.
	 * This has to be done before copying stuff into tsk->thread.fpr/vr
	 * for the reasons explained in the previous comment.
	 */
	regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX));

#ifdef CONFIG_ALTIVEC
	err |= __get_user(v_regs, &sc->v_regs);
	err |= __get_user(tm_v_regs, &tm_sc->v_regs);
	if (err)
		return err;
	if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
		return -EFAULT;
	if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128)))
		return -EFAULT;
	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
	if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
		err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs,
					33 * sizeof(vector128));
		err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
					33 * sizeof(vector128));
		current->thread.used_vr = true;
	}
	else if (tsk->thread.used_vr) {
		memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
		memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
	}
	/* Always get VRSAVE back */
	if (v_regs != NULL && tm_v_regs != NULL) {
		err |= __get_user(tsk->thread.ckvrsave,
				  (u32 __user *)&v_regs[33]);
		err |= __get_user(tsk->thread.vrsave,
				  (u32 __user *)&tm_v_regs[33]);
	}
	else {
		tsk->thread.vrsave = 0;
		tsk->thread.ckvrsave = 0;
	}
	if (cpu_has_feature(CPU_FTR_ALTIVEC))
		mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
#endif /* CONFIG_ALTIVEC */
	/* restore floating point */
	err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
	err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
#ifdef CONFIG_VSX
	/*
	 * Get additional VSX data. Update v_regs to point after the
	 * VMX data.  Copy VSX low doubleword from userspace to local
	 * buffer for formatting, then into the taskstruct.
	 */
	if (v_regs && ((msr & MSR_VSX) != 0)) {
		v_regs += ELF_NVRREG;
		tm_v_regs += ELF_NVRREG;
		err |= copy_vsx_from_user(tsk, tm_v_regs);
		err |= copy_ckvsx_from_user(tsk, v_regs);
		tsk->thread.used_vsr = true;
	} else {
		for (i = 0; i < 32 ; i++) {
			tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
			tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
		}
	}
#endif
	tm_enable();
	/* Make sure the transaction is marked as failed */
	tsk->thread.tm_texasr |= TEXASR_FS;

	/*
	 * Disabling preemption, since it is unsafe to be preempted
	 * with MSR[TS] set without recheckpointing.
	 */
	preempt_disable();

	/* pull in MSR TS bits from user context */
	regs_set_return_msr(regs, regs->msr | (msr & MSR_TS_MASK));

	/*
	 * Ensure that TM is enabled in regs->msr before we leave the signal
	 * handler. It could be the case that (a) user disabled the TM bit
	 * through the manipulation of the MSR bits in uc_mcontext or (b) the
	 * TM bit was disabled because a sufficient number of context switches
	 * happened whilst in the signal handler and load_tm overflowed,
	 * disabling the TM bit. In either case we can end up with an illegal
	 * TM state leading to a TM Bad Thing when we return to userspace.
	 *
	 * CAUTION:
	 * After regs->MSR[TS] being updated, make sure that get_user(),
	 * put_user() or similar functions are *not* called. These
	 * functions can generate page faults which will cause the process
	 * to be de-scheduled with MSR[TS] set but without calling
	 * tm_recheckpoint(). This can cause a bug.
	 */
	regs_set_return_msr(regs, regs->msr | MSR_TM);

	/* This loads the checkpointed FP/VEC state, if used */
	tm_recheckpoint(&tsk->thread);

	msr_check_and_set(msr & (MSR_FP | MSR_VEC));
	if (msr & MSR_FP) {
		load_fp_state(&tsk->thread.fp_state);
		regs_set_return_msr(regs, regs->msr | (MSR_FP | tsk->thread.fpexc_mode));
	}
	if (msr & MSR_VEC) {
		load_vr_state(&tsk->thread.vr_state);
		regs_set_return_msr(regs, regs->msr | MSR_VEC);
	}

	preempt_enable();

	return err;
}
#else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc,
				   struct sigcontext __user *tm_sc)
{
	return -EINVAL;
}
#endif

/*
 * Setup the trampoline code on the stack
 */
static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
{
	int i;
	long err = 0;

	/* Call the handler and pop the dummy stackframe*/
	err |= __put_user(PPC_RAW_BCTRL(), &tramp[0]);
	err |= __put_user(PPC_RAW_ADDI(_R1, _R1, __SIGNAL_FRAMESIZE), &tramp[1]);

	err |= __put_user(PPC_RAW_LI(_R0, syscall), &tramp[2]);
	err |= __put_user(PPC_RAW_SC(), &tramp[3]);

	/* Minimal traceback info */
	for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
		err |= __put_user(0, &tramp[i]);

	if (!err)
		flush_icache_range((unsigned long) &tramp[0],
			   (unsigned long) &tramp[TRAMP_SIZE]);

	return err;
}

/*
 * Userspace code may pass a ucontext which doesn't include VSX added
 * at the end.  We need to check for this case.
 */
#define UCONTEXTSIZEWITHOUTVSX \
		(sizeof(struct ucontext) - 32*sizeof(long))

/*
 * Handle {get,set,swap}_context operations
 */
SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
		struct ucontext __user *, new_ctx, long, ctx_size)
{
	sigset_t set;
	unsigned long new_msr = 0;
	int ctx_has_vsx_region = 0;

	if (new_ctx &&
	    get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
		return -EFAULT;
	/*
	 * Check that the context is not smaller than the original
	 * size (with VMX but without VSX)
	 */
	if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
		return -EINVAL;
	/*
	 * If the new context state sets the MSR VSX bits but
	 * it doesn't provide VSX state.
	 */
	if ((ctx_size < sizeof(struct ucontext)) &&
	    (new_msr & MSR_VSX))
		return -EINVAL;
	/* Does the context have enough room to store VSX data? */
	if (ctx_size >= sizeof(struct ucontext))
		ctx_has_vsx_region = 1;

	if (old_ctx != NULL) {
		prepare_setup_sigcontext(current);
		if (!user_write_access_begin(old_ctx, ctx_size))
			return -EFAULT;

		unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL,
					0, ctx_has_vsx_region, efault_out);
		unsafe_copy_to_user(&old_ctx->uc_sigmask, &current->blocked,
				    sizeof(sigset_t), efault_out);

		user_write_access_end();
	}
	if (new_ctx == NULL)
		return 0;
	if (!access_ok(new_ctx, ctx_size) ||
	    fault_in_readable((char __user *)new_ctx, ctx_size))
		return -EFAULT;

	/*
	 * If we get a fault copying the context into the kernel's
	 * image of the user's registers, we can't just return -EFAULT
	 * because the user's registers will be corrupted.  For instance
	 * the NIP value may have been updated but not some of the
	 * other registers.  Given that we have done the access_ok
	 * and successfully read the first and last bytes of the region
	 * above, this should only happen in an out-of-memory situation
	 * or if another thread unmaps the region containing the context.
	 * We kill the task with a SIGSEGV in this situation.
	 */

	if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) {
		force_fatal_sig(SIGSEGV);
		return -EFAULT;
	}
	set_current_blocked(&set);

	if (!user_read_access_begin(new_ctx, ctx_size))
		return -EFAULT;
	if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) {
		user_read_access_end();
		force_fatal_sig(SIGSEGV);
		return -EFAULT;
	}
	user_read_access_end();

	/* This returns like rt_sigreturn */
	set_thread_flag(TIF_RESTOREALL);

	return 0;

efault_out:
	user_write_access_end();
	return -EFAULT;
}


/*
 * Do a signal return; undo the signal stack.
 */

SYSCALL_DEFINE0(rt_sigreturn)
{
	struct pt_regs *regs = current_pt_regs();
	struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
	sigset_t set;
	unsigned long msr;

	/* Always make any pending restarted system calls return -EINTR */
	current->restart_block.fn = do_no_restart_syscall;

	if (!access_ok(uc, sizeof(*uc)))
		goto badframe;

	if (__get_user_sigset(&set, &uc->uc_sigmask))
		goto badframe;
	set_current_blocked(&set);

	if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) {
		/*
		 * If there is a transactional state then throw it away.
		 * The purpose of a sigreturn is to destroy all traces of the
		 * signal frame, this includes any transactional state created
		 * within in. We only check for suspended as we can never be
		 * active in the kernel, we are active, there is nothing better to
		 * do than go ahead and Bad Thing later.
		 * The cause is not important as there will never be a
		 * recheckpoint so it's not user visible.
		 */
		if (MSR_TM_SUSPENDED(mfmsr()))
			tm_reclaim_current(0);

		/*
		 * Disable MSR[TS] bit also, so, if there is an exception in the
		 * code below (as a page fault in copy_ckvsx_to_user()), it does
		 * not recheckpoint this task if there was a context switch inside
		 * the exception.
		 *
		 * A major page fault can indirectly call schedule(). A reschedule
		 * process in the middle of an exception can have a side effect
		 * (Changing the CPU MSR[TS] state), since schedule() is called
		 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
		 * (switch_to() calls tm_recheckpoint() for the 'new' process). In
		 * this case, the process continues to be the same in the CPU, but
		 * the CPU state just changed.
		 *
		 * This can cause a TM Bad Thing, since the MSR in the stack will
		 * have the MSR[TS]=0, and this is what will be used to RFID.
		 *
		 * Clearing MSR[TS] state here will avoid a recheckpoint if there
		 * is any process reschedule in kernel space. The MSR[TS] state
		 * does not need to be saved also, since it will be replaced with
		 * the MSR[TS] that came from user context later, at
		 * restore_tm_sigcontexts.
		 */
		regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK);

		if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
			goto badframe;
	}

	if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) {
		/* We recheckpoint on return. */
		struct ucontext __user *uc_transact;

		/* Trying to start TM on non TM system */
		if (!cpu_has_feature(CPU_FTR_TM))
			goto badframe;

		if (__get_user(uc_transact, &uc->uc_link))
			goto badframe;
		if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
					   &uc_transact->uc_mcontext))
			goto badframe;
	} else {
		/*
		 * Fall through, for non-TM restore
		 *
		 * Unset MSR[TS] on the thread regs since MSR from user
		 * context does not have MSR active, and recheckpoint was
		 * not called since restore_tm_sigcontexts() was not called
		 * also.
		 *
		 * If not unsetting it, the code can RFID to userspace with
		 * MSR[TS] set, but without CPU in the proper state,
		 * causing a TM bad thing.
		 */
		regs_set_return_msr(current->thread.regs,
				current->thread.regs->msr & ~MSR_TS_MASK);
		if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext)))
			goto badframe;

		unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext,
					  badframe_block);

		user_read_access_end();
	}

	if (restore_altstack(&uc->uc_stack))
		goto badframe;

	set_thread_flag(TIF_RESTOREALL);

	return 0;

badframe_block:
	user_read_access_end();
badframe:
	signal_fault(current, regs, "rt_sigreturn", uc);

	force_sig(SIGSEGV);
	return 0;
}

int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
		struct task_struct *tsk)
{
	struct rt_sigframe __user *frame;
	unsigned long newsp = 0;
	long err = 0;
	struct pt_regs *regs = tsk->thread.regs;
	/* Save the thread's msr before get_tm_stackpointer() changes it */
	unsigned long msr = regs->msr;

	frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);

	/*
	 * This only applies when calling unsafe_setup_sigcontext() and must be
	 * called before opening the uaccess window.
	 */
	if (!MSR_TM_ACTIVE(msr))
		prepare_setup_sigcontext(tsk);

	if (!user_write_access_begin(frame, sizeof(*frame)))
		goto badframe;

	unsafe_put_user(&frame->info, &frame->pinfo, badframe_block);
	unsafe_put_user(&frame->uc, &frame->puc, badframe_block);

	/* Create the ucontext.  */
	unsafe_put_user(0, &frame->uc.uc_flags, badframe_block);
	unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block);

	if (MSR_TM_ACTIVE(msr)) {
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
		/* The ucontext_t passed to userland points to the second
		 * ucontext_t (for transactional state) with its uc_link ptr.
		 */
		unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block);

		user_write_access_end();

		err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
					    &frame->uc_transact.uc_mcontext,
					    tsk, ksig->sig, NULL,
					    (unsigned long)ksig->ka.sa.sa_handler,
					    msr);

		if (!user_write_access_begin(&frame->uc.uc_sigmask,
					     sizeof(frame->uc.uc_sigmask)))
			goto badframe;

#endif
	} else {
		unsafe_put_user(0, &frame->uc.uc_link, badframe_block);
		unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
					NULL, (unsigned long)ksig->ka.sa.sa_handler,
					1, badframe_block);
	}

	unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block);
	user_write_access_end();

	/* Save the siginfo outside of the unsafe block. */
	if (copy_siginfo_to_user(&frame->info, &ksig->info))
		goto badframe;

	/* Make sure signal handler doesn't get spurious FP exceptions */
	tsk->thread.fp_state.fpscr = 0;

	/* Set up to return from userspace. */
	if (tsk->mm->context.vdso) {
		regs_set_return_ip(regs, VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64));
	} else {
		err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
		if (err)
			goto badframe;
		regs_set_return_ip(regs, (unsigned long) &frame->tramp[0]);
	}

	/* Allocate a dummy caller frame for the signal handler. */
	newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
	err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);

	/* Set up "regs" so we "return" to the signal handler. */
	if (is_elf2_task()) {
		regs->ctr = (unsigned long) ksig->ka.sa.sa_handler;
		regs->gpr[12] = regs->ctr;
	} else {
		/* Handler is *really* a pointer to the function descriptor for
		 * the signal routine.  The first entry in the function
		 * descriptor is the entry address of signal and the second
		 * entry is the TOC value we need to use.
		 */
		func_descr_t __user *funct_desc_ptr =
			(func_descr_t __user *) ksig->ka.sa.sa_handler;

		err |= get_user(regs->ctr, &funct_desc_ptr->entry);
		err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
	}

	/* enter the signal handler in native-endian mode */
	regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (MSR_KERNEL & MSR_LE));
	regs->gpr[1] = newsp;
	regs->gpr[3] = ksig->sig;
	regs->result = 0;
	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
		regs->gpr[4] = (unsigned long)&frame->info;
		regs->gpr[5] = (unsigned long)&frame->uc;
		regs->gpr[6] = (unsigned long) frame;
	} else {
		regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
	}
	if (err)
		goto badframe;

	return 0;

badframe_block:
	user_write_access_end();
badframe:
	signal_fault(current, regs, "handle_rt_signal64", frame);

	return 1;
}