summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/signal.c
blob: a0da58db43a86ea9f2ec85154cd46bc2828c822e (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
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
 *  2000-2002   x86-64 support by Andi Kleen
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/tracehook.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/uaccess.h>
#include <linux/user-return-notifier.h>
#include <linux/uprobes.h>
#include <linux/context_tracking.h>

#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/i387.h>
#include <asm/fpu-internal.h>
#include <asm/vdso.h>
#include <asm/mce.h>
#include <asm/sighandling.h>

#ifdef CONFIG_X86_64
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#include <asm/sys_ia32.h>
#endif /* CONFIG_X86_64 */

#include <asm/syscall.h>
#include <asm/syscalls.h>

#include <asm/sigframe.h>

#define COPY(x)			do {			\
	get_user_ex(regs->x, &sc->x);			\
} while (0)

#define GET_SEG(seg)		({			\
	unsigned short tmp;				\
	get_user_ex(tmp, &sc->seg);			\
	tmp;						\
})

#define COPY_SEG(seg)		do {			\
	regs->seg = GET_SEG(seg);			\
} while (0)

#define COPY_SEG_CPL3(seg)	do {			\
	regs->seg = GET_SEG(seg) | 3;			\
} while (0)

int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
		       unsigned long *pax)
{
	void __user *buf;
	unsigned int tmpflags;
	unsigned int err = 0;

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

	get_user_try {

#ifdef CONFIG_X86_32
		set_user_gs(regs, GET_SEG(gs));
		COPY_SEG(fs);
		COPY_SEG(es);
		COPY_SEG(ds);
#endif /* CONFIG_X86_32 */

		COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
		COPY(dx); COPY(cx); COPY(ip);

#ifdef CONFIG_X86_64
		COPY(r8);
		COPY(r9);
		COPY(r10);
		COPY(r11);
		COPY(r12);
		COPY(r13);
		COPY(r14);
		COPY(r15);
#endif /* CONFIG_X86_64 */

#ifdef CONFIG_X86_32
		COPY_SEG_CPL3(cs);
		COPY_SEG_CPL3(ss);
#else /* !CONFIG_X86_32 */
		/* Kernel saves and restores only the CS segment register on signals,
		 * which is the bare minimum needed to allow mixed 32/64-bit code.
		 * App's signal handler can save/restore other segments if needed. */
		COPY_SEG_CPL3(cs);
#endif /* CONFIG_X86_32 */

		get_user_ex(tmpflags, &sc->flags);
		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
		regs->orig_ax = -1;		/* disable syscall checks */

		get_user_ex(buf, &sc->fpstate);

		get_user_ex(*pax, &sc->ax);
	} get_user_catch(err);

	err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));

	return err;
}

int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
		     struct pt_regs *regs, unsigned long mask)
{
	int err = 0;

	put_user_try {

#ifdef CONFIG_X86_32
		put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
		put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
		put_user_ex(regs->es, (unsigned int __user *)&sc->es);
		put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
#endif /* CONFIG_X86_32 */

		put_user_ex(regs->di, &sc->di);
		put_user_ex(regs->si, &sc->si);
		put_user_ex(regs->bp, &sc->bp);
		put_user_ex(regs->sp, &sc->sp);
		put_user_ex(regs->bx, &sc->bx);
		put_user_ex(regs->dx, &sc->dx);
		put_user_ex(regs->cx, &sc->cx);
		put_user_ex(regs->ax, &sc->ax);
#ifdef CONFIG_X86_64
		put_user_ex(regs->r8, &sc->r8);
		put_user_ex(regs->r9, &sc->r9);
		put_user_ex(regs->r10, &sc->r10);
		put_user_ex(regs->r11, &sc->r11);
		put_user_ex(regs->r12, &sc->r12);
		put_user_ex(regs->r13, &sc->r13);
		put_user_ex(regs->r14, &sc->r14);
		put_user_ex(regs->r15, &sc->r15);
#endif /* CONFIG_X86_64 */

		put_user_ex(current->thread.trap_nr, &sc->trapno);
		put_user_ex(current->thread.error_code, &sc->err);
		put_user_ex(regs->ip, &sc->ip);
#ifdef CONFIG_X86_32
		put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
		put_user_ex(regs->flags, &sc->flags);
		put_user_ex(regs->sp, &sc->sp_at_signal);
		put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
#else /* !CONFIG_X86_32 */
		put_user_ex(regs->flags, &sc->flags);
		put_user_ex(regs->cs, &sc->cs);
		put_user_ex(0, &sc->gs);
		put_user_ex(0, &sc->fs);
#endif /* CONFIG_X86_32 */

		put_user_ex(fpstate, &sc->fpstate);

		/* non-iBCS2 extensions.. */
		put_user_ex(mask, &sc->oldmask);
		put_user_ex(current->thread.cr2, &sc->cr2);
	} put_user_catch(err);

	return err;
}

/*
 * Set up a signal frame.
 */

/*
 * Determine which stack to use..
 */
static unsigned long align_sigframe(unsigned long sp)
{
#ifdef CONFIG_X86_32
	/*
	 * Align the stack pointer according to the i386 ABI,
	 * i.e. so that on function entry ((sp + 4) & 15) == 0.
	 */
	sp = ((sp + 4) & -16ul) - 4;
#else /* !CONFIG_X86_32 */
	sp = round_down(sp, 16) - 8;
#endif
	return sp;
}

static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
	     void __user **fpstate)
{
	/* Default to using normal stack */
	unsigned long math_size = 0;
	unsigned long sp = regs->sp;
	unsigned long buf_fx = 0;
	int onsigstack = on_sig_stack(sp);

	/* redzone */
	if (config_enabled(CONFIG_X86_64))
		sp -= 128;

	if (!onsigstack) {
		/* This is the X/Open sanctioned signal stack switching.  */
		if (ka->sa.sa_flags & SA_ONSTACK) {
			if (current->sas_ss_size)
				sp = current->sas_ss_sp + current->sas_ss_size;
		} else if (config_enabled(CONFIG_X86_32) &&
			   (regs->ss & 0xffff) != __USER_DS &&
			   !(ka->sa.sa_flags & SA_RESTORER) &&
			   ka->sa.sa_restorer) {
				/* This is the legacy signal stack switching. */
				sp = (unsigned long) ka->sa.sa_restorer;
		}
	}

	if (used_math()) {
		sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
				     &buf_fx, &math_size);
		*fpstate = (void __user *)sp;
	}

	sp = align_sigframe(sp - frame_size);

	/*
	 * If we are on the alternate signal stack and would overflow it, don't.
	 * Return an always-bogus address instead so we will die with SIGSEGV.
	 */
	if (onsigstack && !likely(on_sig_stack(sp)))
		return (void __user *)-1L;

	/* save i387 and extended state */
	if (used_math() &&
	    save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
		return (void __user *)-1L;

	return (void __user *)sp;
}

#ifdef CONFIG_X86_32
static const struct {
	u16 poplmovl;
	u32 val;
	u16 int80;
} __attribute__((packed)) retcode = {
	0xb858,		/* popl %eax; movl $..., %eax */
	__NR_sigreturn,
	0x80cd,		/* int $0x80 */
};

static const struct {
	u8  movl;
	u32 val;
	u16 int80;
	u8  pad;
} __attribute__((packed)) rt_retcode = {
	0xb8,		/* movl $..., %eax */
	__NR_rt_sigreturn,
	0x80cd,		/* int $0x80 */
	0
};

static int
__setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
	      struct pt_regs *regs)
{
	struct sigframe __user *frame;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (__put_user(sig, &frame->sig))
		return -EFAULT;

	if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
		return -EFAULT;

	if (_NSIG_WORDS > 1) {
		if (__copy_to_user(&frame->extramask, &set->sig[1],
				   sizeof(frame->extramask)))
			return -EFAULT;
	}

	if (current->mm->context.vdso)
		restorer = current->mm->context.vdso +
			selected_vdso32->sym___kernel_sigreturn;
	else
		restorer = &frame->retcode;
	if (ksig->ka.sa.sa_flags & SA_RESTORER)
		restorer = ksig->ka.sa.sa_restorer;

	/* Set up to return from userspace.  */
	err |= __put_user(restorer, &frame->pretcode);

	/*
	 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
	 *
	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
	 * reasons and because gdb uses it as a signature to notice
	 * signal handler stack frames.
	 */
	err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long)frame;
	regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
	regs->ax = (unsigned long)sig;
	regs->dx = 0;
	regs->cx = 0;

	regs->ds = __USER_DS;
	regs->es = __USER_DS;
	regs->ss = __USER_DS;
	regs->cs = __USER_CS;

	return 0;
}

static int __setup_rt_frame(int sig, struct ksignal *ksig,
			    sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	put_user_try {
		put_user_ex(sig, &frame->sig);
		put_user_ex(&frame->info, &frame->pinfo);
		put_user_ex(&frame->uc, &frame->puc);

		/* Create the ucontext.  */
		if (cpu_has_xsave)
			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
		else
			put_user_ex(0, &frame->uc.uc_flags);
		put_user_ex(0, &frame->uc.uc_link);
		save_altstack_ex(&frame->uc.uc_stack, regs->sp);

		/* Set up to return from userspace.  */
		restorer = current->mm->context.vdso +
			selected_vdso32->sym___kernel_sigreturn;
		if (ksig->ka.sa.sa_flags & SA_RESTORER)
			restorer = ksig->ka.sa.sa_restorer;
		put_user_ex(restorer, &frame->pretcode);

		/*
		 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
		 *
		 * WE DO NOT USE IT ANY MORE! It's only left here for historical
		 * reasons and because gdb uses it as a signature to notice
		 * signal handler stack frames.
		 */
		put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
	} put_user_catch(err);
	
	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
				regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long)frame;
	regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
	regs->ax = (unsigned long)sig;
	regs->dx = (unsigned long)&frame->info;
	regs->cx = (unsigned long)&frame->uc;

	regs->ds = __USER_DS;
	regs->es = __USER_DS;
	regs->ss = __USER_DS;
	regs->cs = __USER_CS;

	return 0;
}
#else /* !CONFIG_X86_32 */
static int __setup_rt_frame(int sig, struct ksignal *ksig,
			    sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	void __user *fp = NULL;
	int err = 0;

	frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
		if (copy_siginfo_to_user(&frame->info, &ksig->info))
			return -EFAULT;
	}

	put_user_try {
		/* Create the ucontext.  */
		if (cpu_has_xsave)
			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
		else
			put_user_ex(0, &frame->uc.uc_flags);
		put_user_ex(0, &frame->uc.uc_link);
		save_altstack_ex(&frame->uc.uc_stack, regs->sp);

		/* Set up to return from userspace.  If provided, use a stub
		   already in userspace.  */
		/* x86-64 should always use SA_RESTORER. */
		if (ksig->ka.sa.sa_flags & SA_RESTORER) {
			put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
		} else {
			/* could use a vstub here */
			err |= -EFAULT;
		}
	} put_user_catch(err);

	err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->di = sig;
	/* In case the signal handler was declared without prototypes */
	regs->ax = 0;

	/* This also works for non SA_SIGINFO handlers because they expect the
	   next argument after the signal number on the stack. */
	regs->si = (unsigned long)&frame->info;
	regs->dx = (unsigned long)&frame->uc;
	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;

	regs->sp = (unsigned long)frame;

	/* Set up the CS register to run signal handlers in 64-bit mode,
	   even if the handler happens to be interrupting 32-bit code. */
	regs->cs = __USER_CS;

	return 0;
}
#endif /* CONFIG_X86_32 */

static int x32_setup_rt_frame(struct ksignal *ksig,
			      compat_sigset_t *set,
			      struct pt_regs *regs)
{
#ifdef CONFIG_X86_X32_ABI
	struct rt_sigframe_x32 __user *frame;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
		if (copy_siginfo_to_user32(&frame->info, &ksig->info))
			return -EFAULT;
	}

	put_user_try {
		/* Create the ucontext.  */
		if (cpu_has_xsave)
			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
		else
			put_user_ex(0, &frame->uc.uc_flags);
		put_user_ex(0, &frame->uc.uc_link);
		compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
		put_user_ex(0, &frame->uc.uc__pad0);

		if (ksig->ka.sa.sa_flags & SA_RESTORER) {
			restorer = ksig->ka.sa.sa_restorer;
		} else {
			/* could use a vstub here */
			restorer = NULL;
			err |= -EFAULT;
		}
		put_user_ex(restorer, &frame->pretcode);
	} put_user_catch(err);

	err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
				regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long) frame;
	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;

	/* We use the x32 calling convention here... */
	regs->di = ksig->sig;
	regs->si = (unsigned long) &frame->info;
	regs->dx = (unsigned long) &frame->uc;

	loadsegment(ds, __USER_DS);
	loadsegment(es, __USER_DS);

	regs->cs = __USER_CS;
	regs->ss = __USER_DS;
#endif	/* CONFIG_X86_X32_ABI */

	return 0;
}

/*
 * Do a signal return; undo the signal stack.
 */
#ifdef CONFIG_X86_32
asmlinkage unsigned long sys_sigreturn(void)
{
	struct pt_regs *regs = current_pt_regs();
	struct sigframe __user *frame;
	unsigned long ax;
	sigset_t set;

	frame = (struct sigframe __user *)(regs->sp - 8);

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
		&& __copy_from_user(&set.sig[1], &frame->extramask,
				    sizeof(frame->extramask))))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(regs, &frame->sc, &ax))
		goto badframe;
	return ax;

badframe:
	signal_fault(regs, frame, "sigreturn");

	return 0;
}
#endif /* CONFIG_X86_32 */

asmlinkage long sys_rt_sigreturn(void)
{
	struct pt_regs *regs = current_pt_regs();
	struct rt_sigframe __user *frame;
	unsigned long ax;
	sigset_t set;

	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
		goto badframe;

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

	return ax;

badframe:
	signal_fault(regs, frame, "rt_sigreturn");
	return 0;
}

/*
 * OK, we're invoking a handler:
 */
static int signr_convert(int sig)
{
#ifdef CONFIG_X86_32
	struct thread_info *info = current_thread_info();

	if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
		return info->exec_domain->signal_invmap[sig];
#endif /* CONFIG_X86_32 */
	return sig;
}

static int
setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
{
	int usig = signr_convert(ksig->sig);
	sigset_t *set = sigmask_to_save();
	compat_sigset_t *cset = (compat_sigset_t *) set;

	/* Set up the stack frame */
	if (is_ia32_frame()) {
		if (ksig->ka.sa.sa_flags & SA_SIGINFO)
			return ia32_setup_rt_frame(usig, ksig, cset, regs);
		else
			return ia32_setup_frame(usig, ksig, cset, regs);
	} else if (is_x32_frame()) {
		return x32_setup_rt_frame(ksig, cset, regs);
	} else {
		return __setup_rt_frame(ksig->sig, ksig, set, regs);
	}
}

static void
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
	bool failed;
	/* Are we from a system call? */
	if (syscall_get_nr(current, regs) >= 0) {
		/* If so, check system call restarting.. */
		switch (syscall_get_error(current, regs)) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->ax = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
				regs->ax = -EINTR;
				break;
			}
		/* fallthrough */
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;
		}
	}

	/*
	 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
	 * flag so that register information in the sigcontext is correct.
	 */
	if (unlikely(regs->flags & X86_EFLAGS_TF) &&
	    likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
		regs->flags &= ~X86_EFLAGS_TF;

	failed = (setup_rt_frame(ksig, regs) < 0);
	if (!failed) {
		/*
		 * Clear the direction flag as per the ABI for function entry.
		 *
		 * Clear RF when entering the signal handler, because
		 * it might disable possible debug exception from the
		 * signal handler.
		 *
		 * Clear TF when entering the signal handler, but
		 * notify any tracer that was single-stepping it.
		 * The tracer may want to single-step inside the
		 * handler too.
		 */
		regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
	}
	signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP));
}

#ifdef CONFIG_X86_32
#define NR_restart_syscall	__NR_restart_syscall
#else /* !CONFIG_X86_32 */
#define NR_restart_syscall	\
	test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
#endif /* CONFIG_X86_32 */

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 */
static void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;

	if (get_signal(&ksig)) {
		/* Whee! Actually deliver the signal.  */
		handle_signal(&ksig, regs);
		return;
	}

	/* Did we come from a system call? */
	if (syscall_get_nr(current, regs) >= 0) {
		/* Restart the system call - no handlers present */
		switch (syscall_get_error(current, regs)) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;

		case -ERESTART_RESTARTBLOCK:
			regs->ax = NR_restart_syscall;
			regs->ip -= 2;
			break;
		}
	}

	/*
	 * If there's no signal to deliver, we just put the saved sigmask
	 * back.
	 */
	restore_saved_sigmask();
}

/*
 * notification of userspace execution resumption
 * - triggered by the TIF_WORK_MASK flags
 */
__visible void
do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
{
	user_exit();

#ifdef CONFIG_X86_MCE
	/* notify userspace of pending MCEs */
	if (thread_info_flags & _TIF_MCE_NOTIFY)
		mce_notify_process();
#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */

	if (thread_info_flags & _TIF_UPROBE)
		uprobe_notify_resume(regs);

	/* deal with pending signal delivery */
	if (thread_info_flags & _TIF_SIGPENDING)
		do_signal(regs);

	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
		clear_thread_flag(TIF_NOTIFY_RESUME);
		tracehook_notify_resume(regs);
	}
	if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
		fire_user_return_notifiers();

	user_enter();
}

void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
{
	struct task_struct *me = current;

	if (show_unhandled_signals && printk_ratelimit()) {
		printk("%s"
		       "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
		       task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
		       me->comm, me->pid, where, frame,
		       regs->ip, regs->sp, regs->orig_ax);
		print_vma_addr(" in ", regs->ip);
		pr_cont("\n");
	}

	force_sig(SIGSEGV, me);
}

#ifdef CONFIG_X86_X32_ABI
asmlinkage long sys32_x32_rt_sigreturn(void)
{
	struct pt_regs *regs = current_pt_regs();
	struct rt_sigframe_x32 __user *frame;
	sigset_t set;
	unsigned long ax;

	frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
		goto badframe;

	if (compat_restore_altstack(&frame->uc.uc_stack))
		goto badframe;

	return ax;

badframe:
	signal_fault(regs, frame, "x32 rt_sigreturn");
	return 0;
}
#endif