summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/signal_64.c
blob: 7a76ee48a952db2b1409c397f7c0e0acfc9f2edd (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
/*
 *  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
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#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 <asm/sigcontext.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.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 "signal.h"

#define DEBUG_SIG 0

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

#define TRAMP_TRACEBACK	3
#define TRAMP_SIZE	6

/*
 * 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;
	/* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
	char abigap[288];
} __attribute__ ((aligned (16)));

static const char fmt32[] = KERN_INFO \
	"%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n";
static const char fmt64[] = KERN_INFO \
	"%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";

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

static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
		 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 = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
#endif
	unsigned long msr = regs->msr;
	long err = 0;

	flush_fp_to_thread(current);

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

	/* save altivec registers */
	if (current->thread.used_vr) {
		flush_altivec_to_thread(current);
		/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
		err |= __copy_to_user(v_regs, current->thread.vr, 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.
	 */
	err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
#else /* CONFIG_ALTIVEC */
	err |= __put_user(0, &sc->v_regs);
#endif /* CONFIG_ALTIVEC */
	flush_fp_to_thread(current);
	/* copy fpr regs and fpscr */
	err |= copy_fpr_to_user(&sc->fp_regs, current);
#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 (current->thread.used_vsr && ctx_has_vsx_region) {
		__giveup_vsx(current);
		v_regs += ELF_NVRREG;
		err |= copy_vsx_to_user(v_regs, current);
		/* 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);
	WARN_ON(!FULL_REGS(regs));
	err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
	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;
}

#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 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 pt_regs *regs,
				 int signr, sigset_t *set, unsigned long handler)
{
	/* 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 = (elf_vrreg_t __user *)
		(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
	elf_vrreg_t __user *tm_v_regs = (elf_vrreg_t __user *)
		(((unsigned long)tm_sc->vmx_reserve + 15) & ~0xful);
#endif
	unsigned long msr = regs->msr;
	long err = 0;

	BUG_ON(!MSR_TM_ACTIVE(regs->msr));

	/* tm_reclaim rolls back all reg states, saving checkpointed (older)
	 * GPRs to thread.ckpt_regs and (if used) FPRs to (newer)
	 * thread.transact_fp and/or VRs to (newer) thread.transact_vr.
	 * THEN we save out FP/VRs, if necessary, to the checkpointed (older)
	 * thread.fr[]/vr[]s.  The transactional (newer) GPRs are on the
	 * stack, in *regs.
	 */
	tm_enable();
	tm_reclaim(&current->thread, msr, TM_CAUSE_SIGNAL);

	flush_fp_to_thread(current);

#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 (current->thread.used_vr) {
		flush_altivec_to_thread(current);
		/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
		err |= __copy_to_user(v_regs, current->thread.vr,
				      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,
					      current->thread.transact_vr,
					      33 * sizeof(vector128));
		else
			err |= __copy_to_user(tm_v_regs,
					      current->thread.vr,
					      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.
	 */
	err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
	if (msr & MSR_VEC)
		err |= __put_user(current->thread.transact_vrsave,
				  (u32 __user *)&tm_v_regs[33]);
	else
		err |= __put_user(current->thread.vrsave,
				  (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_fpr_to_user(&sc->fp_regs, current);
	if (msr & MSR_FP)
		err |= copy_transact_fpr_to_user(&tm_sc->fp_regs, current);
	else
		err |= copy_fpr_to_user(&tm_sc->fp_regs, current);

#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 (current->thread.used_vsr) {
		__giveup_vsx(current);
		v_regs += ELF_NVRREG;
		tm_v_regs += ELF_NVRREG;

		err |= copy_vsx_to_user(v_regs, current);

		if (msr & MSR_VSX)
			err |= copy_transact_vsx_to_user(tm_v_regs, current);
		else
			err |= copy_vsx_to_user(tm_v_regs, current);

		/* 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);
	WARN_ON(!FULL_REGS(regs));
	err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
	err |= __copy_to_user(&sc->gp_regs,
			      &current->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.
 */

static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
			      struct sigcontext __user *sc)
{
#ifdef CONFIG_ALTIVEC
	elf_vrreg_t __user *v_regs;
#endif
	unsigned long err = 0;
	unsigned long save_r13 = 0;
	unsigned long msr;
#ifdef CONFIG_VSX
	int i;
#endif

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

	/* copy the GPRs */
	err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
	err |= __get_user(regs->nip, &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]);
	if (sig)
		regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
	err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
	err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
	err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
	err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
	err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
	/* skip SOFTE */
	regs->trap = 0;
	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]);

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

	/*
	 * Do this before updating the thread state in
	 * current->thread.fpr/vr.  That way, if we get preempted
	 * and another task grabs the FPU/Altivec, it won't be
	 * tempted to save the current CPU state into the thread_struct
	 * and corrupt what we are writing there.
	 */
	discard_lazy_cpu_state();

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

#ifdef CONFIG_ALTIVEC
	err |= __get_user(v_regs, &sc->v_regs);
	if (err)
		return err;
	if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
		return -EFAULT;
	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
	if (v_regs != 0 && (msr & MSR_VEC) != 0)
		err |= __copy_from_user(current->thread.vr, v_regs,
					33 * sizeof(vector128));
	else if (current->thread.used_vr)
		memset(current->thread.vr, 0, 33 * sizeof(vector128));
	/* Always get VRSAVE back */
	if (v_regs != 0)
		err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
	else
		current->thread.vrsave = 0;
#endif /* CONFIG_ALTIVEC */
	/* restore floating point */
	err |= copy_fpr_from_user(current, &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.
	 */
	v_regs += ELF_NVRREG;
	if ((msr & MSR_VSX) != 0)
		err |= copy_vsx_from_user(current, v_regs);
	else
		for (i = 0; i < 32 ; i++)
			current->thread.fpr[i][TS_VSRLOWOFFSET] = 0;
#endif
	return err;
}

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

static long restore_tm_sigcontexts(struct pt_regs *regs,
				   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;
#ifdef CONFIG_VSX
	int i;
#endif
	/* copy the GPRs */
	err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
	err |= __copy_from_user(&current->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(current->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]);
	regs->msr = (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(current->thread.ckpt_regs.ctr,
			  &sc->gp_regs[PT_CTR]);
	err |= __get_user(current->thread.ckpt_regs.link,
			  &sc->gp_regs[PT_LNK]);
	err |= __get_user(current->thread.ckpt_regs.xer,
			  &sc->gp_regs[PT_XER]);
	err |= __get_user(current->thread.ckpt_regs.ccr,
			  &sc->gp_regs[PT_CCR]);

	/* These regs are not checkpointed; they can go in 'regs'. */
	err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
	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]);

	/*
	 * Do this before updating the thread state in
	 * current->thread.fpr/vr.  That way, if we get preempted
	 * and another task grabs the FPU/Altivec, it won't be
	 * tempted to save the current CPU state into the thread_struct
	 * and corrupt what we are writing there.
	 */
	discard_lazy_cpu_state();

	/*
	 * Force reload of FP/VEC.
	 * This has to be done before copying stuff into current->thread.fpr/vr
	 * for the reasons explained in the previous comment.
	 */
	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(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
		return -EFAULT;
	if (tm_v_regs && !access_ok(VERIFY_READ,
				    tm_v_regs, 34 * sizeof(vector128)))
		return -EFAULT;
	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
	if (v_regs != 0 && tm_v_regs != 0 && (msr & MSR_VEC) != 0) {
		err |= __copy_from_user(current->thread.vr, v_regs,
					33 * sizeof(vector128));
		err |= __copy_from_user(current->thread.transact_vr, tm_v_regs,
					33 * sizeof(vector128));
	}
	else if (current->thread.used_vr) {
		memset(current->thread.vr, 0, 33 * sizeof(vector128));
		memset(current->thread.transact_vr, 0, 33 * sizeof(vector128));
	}
	/* Always get VRSAVE back */
	if (v_regs != 0 && tm_v_regs != 0) {
		err |= __get_user(current->thread.vrsave,
				  (u32 __user *)&v_regs[33]);
		err |= __get_user(current->thread.transact_vrsave,
				  (u32 __user *)&tm_v_regs[33]);
	}
	else {
		current->thread.vrsave = 0;
		current->thread.transact_vrsave = 0;
	}
#endif /* CONFIG_ALTIVEC */
	/* restore floating point */
	err |= copy_fpr_from_user(current, &sc->fp_regs);
	err |= copy_transact_fpr_from_user(current, &tm_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(current, v_regs);
		err |= copy_transact_vsx_from_user(current, tm_v_regs);
	} else {
		for (i = 0; i < 32 ; i++) {
			current->thread.fpr[i][TS_VSRLOWOFFSET] = 0;
			current->thread.transact_fpr[i][TS_VSRLOWOFFSET] = 0;
		}
	}
#endif
	tm_enable();
	/* This loads the checkpointed FP/VEC state, if used */
	tm_recheckpoint(&current->thread, msr);
	/* The task has moved into TM state S, so ensure MSR reflects this: */
	regs->msr = (regs->msr & ~MSR_TS_MASK) | __MASK(33);

	/* This loads the speculative FP/VEC state, if used */
	if (msr & MSR_FP) {
		do_load_up_transact_fpu(&current->thread);
		regs->msr |= (MSR_FP | current->thread.fpexc_mode);
	}
	if (msr & MSR_VEC) {
		do_load_up_transact_altivec(&current->thread);
		regs->msr |= MSR_VEC;
	}

	return err;
}
#endif

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

	/* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
	err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
	/* li r0, __NR_[rt_]sigreturn| */
	err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
	/* sc */
	err |= __put_user(0x44000002UL, &tramp[2]);

	/* 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
 */
int sys_swapcontext(struct ucontext __user *old_ctx,
		    struct ucontext __user *new_ctx,
		    long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
{
	unsigned char tmp;
	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) {
		if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
		    || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0,
					ctx_has_vsx_region)
		    || __copy_to_user(&old_ctx->uc_sigmask,
				      &current->blocked, sizeof(sigset_t)))
			return -EFAULT;
	}
	if (new_ctx == NULL)
		return 0;
	if (!access_ok(VERIFY_READ, new_ctx, ctx_size)
	    || __get_user(tmp, (u8 __user *) new_ctx)
	    || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
		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 (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
		do_exit(SIGSEGV);
	set_current_blocked(&set);
	if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
		do_exit(SIGSEGV);

	/* This returns like rt_sigreturn */
	set_thread_flag(TIF_RESTOREALL);
	return 0;
}


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

int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
		     unsigned long r6, unsigned long r7, unsigned long r8,
		     struct pt_regs *regs)
{
	struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
	sigset_t set;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	unsigned long msr;
#endif

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

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

	if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
		goto badframe;
	set_current_blocked(&set);
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
		goto badframe;
	if (MSR_TM_SUSPENDED(msr)) {
		/* We recheckpoint on return. */
		struct ucontext __user *uc_transact;
		if (__get_user(uc_transact, &uc->uc_link))
			goto badframe;
		if (restore_tm_sigcontexts(regs, &uc->uc_mcontext,
					   &uc_transact->uc_mcontext))
			goto badframe;
	}
	else
	/* Fall through, for non-TM restore */
#endif
	if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
		goto badframe;

	/* do_sigaltstack expects a __user pointer and won't modify
	 * what's in there anyway
	 */
	do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);

	set_thread_flag(TIF_RESTOREALL);
	return 0;

badframe:
#if DEBUG_SIG
	printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
	       regs, uc, &uc->uc_mcontext);
#endif
	if (show_unhandled_signals)
		printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
				   current->comm, current->pid, "rt_sigreturn",
				   (long)uc, regs->nip, regs->link);

	force_sig(SIGSEGV, current);
	return 0;
}

int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info,
		sigset_t *set, struct pt_regs *regs)
{
	/* 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;
	struct rt_sigframe __user *frame;
	unsigned long newsp = 0;
	long err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame), 0);
	if (unlikely(frame == NULL))
		goto badframe;

	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	err |= copy_siginfo_to_user(&frame->info, info);
	if (err)
		goto badframe;

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->gpr[1]),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	if (MSR_TM_ACTIVE(regs->msr)) {
		/* The ucontext_t passed to userland points to the second
		 * ucontext_t (for transactional state) with its uc_link ptr.
		 */
		err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
		err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
					    &frame->uc_transact.uc_mcontext,
					    regs, signr,
					    NULL,
					    (unsigned long)ka->sa.sa_handler);
	} else
#endif
	{
		err |= __put_user(0, &frame->uc.uc_link);
		err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr,
					NULL, (unsigned long)ka->sa.sa_handler,
					1);
	}
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto badframe;

	/* Make sure signal handler doesn't get spurious FP exceptions */
	current->thread.fpscr.val = 0;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	/* Remove TM bits from thread's MSR.  The MSR in the sigcontext
	 * just indicates to userland that we were doing a transaction, but we
	 * don't want to return in transactional state:
	 */
	regs->msr &= ~MSR_TS_MASK;
#endif

	/* Set up to return from userspace. */
	if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
		regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
	} else {
		err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
		if (err)
			goto badframe;
		regs->link = (unsigned long) &frame->tramp[0];
	}
	funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;

	/* 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. */
	err |= get_user(regs->nip, &funct_desc_ptr->entry);
	/* enter the signal handler in big-endian mode */
	regs->msr &= ~MSR_LE;
	regs->gpr[1] = newsp;
	err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
	regs->gpr[3] = signr;
	regs->result = 0;
	if (ka->sa.sa_flags & SA_SIGINFO) {
		err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
		err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
		regs->gpr[6] = (unsigned long) frame;
	} else {
		regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
	}
	if (err)
		goto badframe;

	return 1;

badframe:
#if DEBUG_SIG
	printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
	       regs, frame, newsp);
#endif
	if (show_unhandled_signals)
		printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
				   current->comm, current->pid, "setup_rt_frame",
				   (long)frame, regs->nip, regs->link);

	force_sigsegv(signr, current);
	return 0;
}