summaryrefslogtreecommitdiffstats
path: root/arch/ppc/kernel/signal.c
blob: 79847fa0d759af9b8b911f457b079b36eaebd3ac (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
/*
 *  linux/arch/ppc/kernel/signal.c
 *
 *  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/smp_lock.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/elf.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>

#define DEBUG_SIG 0

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

#ifndef MIN
#define MIN(a,b) (((a) < (b)) ? (a) : (b))
#endif

#define GP_REGS_SIZE	MIN(sizeof(elf_gregset_t), sizeof(struct pt_regs))

/* 
 * These are the flags in the MSR that the user is allowed to change
 * by modifying the saved value of the MSR on the stack.  SE and BE
 * should not be in this list since gdb may want to change these.  I.e,
 * you should be able to step out of a signal handler to see what
 * instruction executes next after the signal handler completes.
 * Alternately, if you stepped into a signal handler, you should be
 * able to continue 'til the next breakpoint from within the signal
 * handler, even if the handler returns.
 */
#define MSR_USERCHANGE	(MSR_FE0 | MSR_FE1)

int do_signal(sigset_t *oldset, struct pt_regs *regs);
extern int sys_wait4(pid_t pid, unsigned long *stat_addr,
		     int options, unsigned long *ru);

int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
{
	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
		return -EFAULT;
	if (from->si_code < 0)
		return __copy_to_user(to, from, sizeof(siginfo_t));
	else {
		int err;

		/* If you change siginfo_t structure, please be sure
		   this code is fixed accordingly.
		   It should never copy any pad contained in the structure
		   to avoid security leaks, but must copy the generic
		   3 ints plus the relevant union member.  */
		err = __put_user(from->si_signo, &to->si_signo);
		err |= __put_user(from->si_errno, &to->si_errno);
		err |= __put_user((short)from->si_code, &to->si_code);
		/* First 32bits of unions are always present.  */
		err |= __put_user(from->si_pid, &to->si_pid);
		switch (from->si_code >> 16) {
		case __SI_FAULT >> 16:
			break;
		case __SI_CHLD >> 16:
			err |= __put_user(from->si_utime, &to->si_utime);
			err |= __put_user(from->si_stime, &to->si_stime);
			err |= __put_user(from->si_status, &to->si_status);
		default:
			err |= __put_user(from->si_uid, &to->si_uid);
			break;
		/* case __SI_RT: This is not generated by the kernel as of now.  */
		}
		return err;
	}
}

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
int
sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int p7,
	       struct pt_regs *regs)
{
	sigset_t saveset;

	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sigmask_lock);
	saveset = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	regs->gpr[3] = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, regs))
			/*
			 * If a signal handler needs to be called,
			 * do_signal() has set R3 to the signal number (the
			 * first argument of the signal handler), so don't
			 * overwrite that with EINTR !
			 * In the other cases, do_signal() doesn't touch 
			 * R3, so it's still set to -EINTR (see above).
			 */
			return regs->gpr[3];
	}
}

int
sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, int p3, int p4, int p6,
		  int p7, struct pt_regs *regs)
{
	sigset_t saveset, newset;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	if (copy_from_user(&newset, unewset, sizeof(newset)))
		return -EFAULT;
	sigdelsetmask(&newset, ~_BLOCKABLE);

	spin_lock_irq(&current->sigmask_lock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	regs->gpr[3] = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, regs))
			return regs->gpr[3];
	}
}


asmlinkage int
sys_sigaltstack(const stack_t *uss, stack_t *uoss)
{
	struct pt_regs *regs = (struct pt_regs *) &uss;
	return do_sigaltstack(uss, uoss, regs->gpr[1]);
}

int 
sys_sigaction(int sig, const struct old_sigaction *act,
	      struct old_sigaction *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	if (act) {
		old_sigset_t mask;
		if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
			return -EFAULT;
		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
		__get_user(mask, &act->sa_mask);
		siginitset(&new_ka.sa.sa_mask, mask);
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
			return -EFAULT;
		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	}

	return ret;
}

/*
 * When we have signals to deliver, we set up on the
 * user stack, going down from the original stack pointer:
 *	a sigregs struct
 *	one or more sigcontext structs with
 *	a gap of __SIGNAL_FRAMESIZE bytes
 *
 * Each of these things must be a multiple of 16 bytes in size.
 *
 */
struct sigregs {
	elf_gregset_t	gp_regs;
	double		fp_regs[ELF_NFPREG];
	unsigned long	tramp[2];
	/* Programs using the rs6000/xcoff abi can save up to 19 gp regs
	   and 18 fp regs below sp before decrementing it. */
	int		abigap[56];
};

struct rt_sigframe
{
	unsigned long	_unused[2];
	struct siginfo *pinfo;
	void *puc;
	struct siginfo info;
	struct ucontext uc;
};


/*
 *  When we have rt signals to deliver, we set up on the
 *  user stack, going down from the original stack pointer:
 *	   a sigregs struct
 *	   one rt_sigframe struct (siginfo + ucontext)
 *	   a gap of __SIGNAL_FRAMESIZE bytes
 *
 *  Each of these things must be a multiple of 16 bytes in size.
 *
 */
asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_sigframe *rt_sf;
	struct sigcontext_struct sigctx;
	struct sigregs *sr;
	int ret;
	elf_gregset_t saved_regs;  /* an array of ELF_NGREG unsigned longs */
	sigset_t set;
	stack_t st;
	unsigned long prevsp;

	rt_sf = (struct rt_sigframe *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
	if (copy_from_user(&sigctx, &rt_sf->uc.uc_mcontext, sizeof(sigctx))
	    || copy_from_user(&set, &rt_sf->uc.uc_sigmask, sizeof(set))
	    || copy_from_user(&st, &rt_sf->uc.uc_stack, sizeof(st)))
		goto badframe;
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	current->blocked = set;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	rt_sf++;			/* Look at next rt_sigframe */
	if (rt_sf == (struct rt_sigframe *)(sigctx.regs)) {
		/* Last stacked signal - restore registers -
		 * sigctx is initialized to point to the 
		 * preamble frame (where registers are stored) 
		 * see handle_signal()
		 */
		sr = (struct sigregs *) sigctx.regs;
		if (regs->msr & MSR_FP )
			giveup_fpu(current);
		if (copy_from_user(saved_regs, &sr->gp_regs,
				   sizeof(sr->gp_regs)))
			goto badframe;
		saved_regs[PT_MSR] = (regs->msr & ~MSR_USERCHANGE)
			| (saved_regs[PT_MSR] & MSR_USERCHANGE);
		memcpy(regs, saved_regs, GP_REGS_SIZE);
		if (copy_from_user(current->thread.fpr, &sr->fp_regs,
				   sizeof(sr->fp_regs)))
			goto badframe;
		/* This function sets back the stack flags into
		   the current task structure.  */
		sys_sigaltstack(&st, NULL);

		ret = regs->result;
	} else {
		/* More signals to go */
		/* Set up registers for next signal handler */
		regs->gpr[1] = (unsigned long)rt_sf - __SIGNAL_FRAMESIZE;
		if (copy_from_user(&sigctx, &rt_sf->uc.uc_mcontext, sizeof(sigctx)))
			goto badframe;
		sr = (struct sigregs *) sigctx.regs;
		regs->gpr[3] = ret = sigctx.signal;
		/* Get the siginfo   */
		get_user(regs->gpr[4], (unsigned long *)&rt_sf->pinfo);
		/* Get the ucontext */
		get_user(regs->gpr[5], (unsigned long *)&rt_sf->puc);
		regs->gpr[6] = (unsigned long) rt_sf;

		regs->link = (unsigned long) &sr->tramp;
		regs->nip = sigctx.handler;
		if (get_user(prevsp, &sr->gp_regs[PT_R1])
		    || put_user(prevsp, (unsigned long *) regs->gpr[1]))
			goto badframe;
	}
	return ret;

badframe:
	lock_kernel();
	do_exit(SIGSEGV);
}

static void
setup_rt_frame(struct pt_regs *regs, struct sigregs *frame,
	       signed long newsp)
{
	struct rt_sigframe *rt_sf = (struct rt_sigframe *) newsp;

	/* Set up preamble frame */
	if (verify_area(VERIFY_WRITE, frame, sizeof(*frame)))
		goto badframe;
	if (regs->msr & MSR_FP)
		giveup_fpu(current);
	if (__copy_to_user(&frame->gp_regs, regs, GP_REGS_SIZE)
	    || __copy_to_user(&frame->fp_regs, current->thread.fpr,
			      ELF_NFPREG * sizeof(double))
	/* Set up to return from user space.
	   It calls the sc exception at offset 0x9999 
	   for sys_rt_sigreturn().
	*/
	    || __put_user(0x38006666UL, &frame->tramp[0])	/* li r0,0x6666 */
	    || __put_user(0x44000002UL, &frame->tramp[1]))	/* sc */
		goto badframe;
	flush_icache_range((unsigned long) &frame->tramp[0],
			   (unsigned long) &frame->tramp[2]);

	/* Retrieve rt_sigframe from stack and
	   set up registers for signal handler
	*/
	newsp -= __SIGNAL_FRAMESIZE;
	if (put_user(regs->gpr[1], (unsigned long *)newsp)
	    || get_user(regs->nip, &rt_sf->uc.uc_mcontext.handler)
	    || get_user(regs->gpr[3], &rt_sf->uc.uc_mcontext.signal)
	    || get_user(regs->gpr[4], (unsigned long *)&rt_sf->pinfo)
	    || get_user(regs->gpr[5], (unsigned long *)&rt_sf->puc))
		goto badframe;

	regs->gpr[1] = newsp;
	regs->gpr[6] = (unsigned long) rt_sf;
	regs->link = (unsigned long) frame->tramp;

	return;

badframe:
#if DEBUG_SIG
	printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
	       regs, frame, newsp);
#endif
	lock_kernel();
	do_exit(SIGSEGV);
}

/*
 * Do a signal return; undo the signal stack.
 */
int sys_sigreturn(struct pt_regs *regs)
{
	struct sigcontext_struct *sc, sigctx;
	struct sigregs *sr;
	int ret;
	elf_gregset_t saved_regs;  /* an array of ELF_NGREG unsigned longs */
	sigset_t set;
	unsigned long prevsp;

	sc = (struct sigcontext_struct *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
	if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
		goto badframe;

	set.sig[0] = sigctx.oldmask;
#if _NSIG_WORDS > 1
	set.sig[1] = sigctx._unused[3];
#endif
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	current->blocked = set;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	sc++;			/* Look at next sigcontext */
	if (sc == (struct sigcontext_struct *)(sigctx.regs)) {
		/* Last stacked signal - restore registers */
		sr = (struct sigregs *) sigctx.regs;
		if (regs->msr & MSR_FP )
			giveup_fpu(current);
		if (copy_from_user(saved_regs, &sr->gp_regs,
				   sizeof(sr->gp_regs)))
			goto badframe;
		saved_regs[PT_MSR] = (regs->msr & ~MSR_USERCHANGE)
			| (saved_regs[PT_MSR] & MSR_USERCHANGE);
		memcpy(regs, saved_regs, GP_REGS_SIZE);

		if (copy_from_user(current->thread.fpr, &sr->fp_regs,
				   sizeof(sr->fp_regs)))
			goto badframe;

		ret = regs->result;

	} else {
		/* More signals to go */
		regs->gpr[1] = (unsigned long)sc - __SIGNAL_FRAMESIZE;
		if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
			goto badframe;
		sr = (struct sigregs *) sigctx.regs;
		regs->gpr[3] = ret = sigctx.signal;
		regs->gpr[4] = (unsigned long) sc;
		regs->link = (unsigned long) &sr->tramp;
		regs->nip = sigctx.handler;

		if (get_user(prevsp, &sr->gp_regs[PT_R1])
		    || put_user(prevsp, (unsigned long *) regs->gpr[1]))
			goto badframe;
	}
	return ret;

badframe:
	lock_kernel();
	do_exit(SIGSEGV);
}	

/*
 * Set up a signal frame.
 */
static void
setup_frame(struct pt_regs *regs, struct sigregs *frame,
	    unsigned long newsp)
{
	struct sigcontext_struct *sc = (struct sigcontext_struct *) newsp;

	if (verify_area(VERIFY_WRITE, frame, sizeof(*frame)))
		goto badframe;
		if (regs->msr & MSR_FP)
			giveup_fpu(current);
	if (__copy_to_user(&frame->gp_regs, regs, GP_REGS_SIZE)
	    || __copy_to_user(&frame->fp_regs, current->thread.fpr,
			      ELF_NFPREG * sizeof(double))
	    || __put_user(0x38007777UL, &frame->tramp[0])    /* li r0,0x7777 */
	    || __put_user(0x44000002UL, &frame->tramp[1]))   /* sc */
		goto badframe;
	flush_icache_range((unsigned long) &frame->tramp[0],
			   (unsigned long) &frame->tramp[2]);

	newsp -= __SIGNAL_FRAMESIZE;
	if (put_user(regs->gpr[1], (unsigned long *)newsp)
	    || get_user(regs->nip, &sc->handler)
	    || get_user(regs->gpr[3], &sc->signal))
		goto badframe;
	regs->gpr[1] = newsp;
	regs->gpr[4] = (unsigned long) sc;
	regs->link = (unsigned long) frame->tramp;

	return;

badframe:
#if DEBUG_SIG
	printk("badframe in setup_frame, regs=%p frame=%p newsp=%lx\n",
	       regs, frame, newsp);
#endif
	lock_kernel();
	do_exit(SIGSEGV);
}

/*
 * OK, we're invoking a handler
 */
static void
handle_signal(unsigned long sig, struct k_sigaction *ka,
	      siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
	      unsigned long *newspp, unsigned long frame)
{
	struct sigcontext_struct *sc;
	struct rt_sigframe *rt_sf;

	if (regs->trap == 0x0C00 /* System Call! */
	    && ((int)regs->result == -ERESTARTNOHAND ||
		((int)regs->result == -ERESTARTSYS &&
		 !(ka->sa.sa_flags & SA_RESTART))))
		regs->result = -EINTR;

	/* Set up Signal Frame */
	if (ka->sa.sa_flags & SA_SIGINFO) {
		/* Put a Real Time Context onto stack */
		*newspp -= sizeof(*rt_sf);
		rt_sf = (struct rt_sigframe *) *newspp;
		if (verify_area(VERIFY_WRITE, rt_sf, sizeof(*rt_sf)))
			goto badframe;

		if (__put_user((unsigned long) ka->sa.sa_handler, &rt_sf->uc.uc_mcontext.handler)
		    || __put_user(&rt_sf->info, &rt_sf->pinfo)
		    || __put_user(&rt_sf->uc, &rt_sf->puc)
		    /* Put the siginfo */
		    || __copy_to_user(&rt_sf->info, info, sizeof(*info))
		    /* Create the ucontext */
		    || __put_user(0, &rt_sf->uc.uc_flags)
		    || __put_user(0, &rt_sf->uc.uc_link)
		    || __put_user(current->sas_ss_sp, &rt_sf->uc.uc_stack.ss_sp)
		    || __put_user(sas_ss_flags(regs->gpr[1]), 
				  &rt_sf->uc.uc_stack.ss_flags)
		    || __put_user(current->sas_ss_size, &rt_sf->uc.uc_stack.ss_size)
		    || __copy_to_user(&rt_sf->uc.uc_sigmask, oldset, sizeof(*oldset))
		    /* mcontext.regs points to preamble register frame */
		    || __put_user((struct pt_regs *)frame, &rt_sf->uc.uc_mcontext.regs)
		    || __put_user(sig, &rt_sf->uc.uc_mcontext.signal))
			goto badframe;
	} else {
		/* Put another sigcontext on the stack */
		*newspp -= sizeof(*sc);
		sc = (struct sigcontext_struct *) *newspp;
		if (verify_area(VERIFY_WRITE, sc, sizeof(*sc)))
			goto badframe;
		
		if (__put_user((unsigned long) ka->sa.sa_handler, &sc->handler)
		    || __put_user(oldset->sig[0], &sc->oldmask)
#if _NSIG_WORDS > 1
		    || __put_user(oldset->sig[1], &sc->_unused[3])
#endif
		    || __put_user((struct pt_regs *)frame, &sc->regs)
		    || __put_user(sig, &sc->signal))
			goto badframe;
	}

	if (ka->sa.sa_flags & SA_ONESHOT)
		ka->sa.sa_handler = SIG_DFL;

	if (!(ka->sa.sa_flags & SA_NODEFER)) {
		spin_lock_irq(&current->sigmask_lock);
		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
		sigaddset(&current->blocked,sig);
		recalc_sigpending(current);
		spin_unlock_irq(&current->sigmask_lock);
	}
	return;

badframe:
#if DEBUG_SIG
	printk("badframe in handle_signal, regs=%p frame=%lx newsp=%lx\n",
	       regs, frame, *newspp);
	printk("sc=%p sig=%d ka=%p info=%p oldset=%p\n", sc, sig, ka, info, oldset);
#endif
	lock_kernel();
	do_exit(SIGSEGV);
}

/*
 * 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.
 */
int do_signal(sigset_t *oldset, struct pt_regs *regs)
{
	siginfo_t info;
	struct k_sigaction *ka;
	unsigned long frame, newsp;

	if (!oldset)
		oldset = &current->blocked;

	newsp = frame = 0;

	for (;;) {
		unsigned long signr;

		spin_lock_irq(&current->sigmask_lock);
		signr = dequeue_signal(&current->blocked, &info);
		spin_unlock_irq(&current->sigmask_lock);

		if (!signr)
			break;

		if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
			/* Let the debugger run.  */
			current->exit_code = signr;
			current->state = TASK_STOPPED;
			notify_parent(current, SIGCHLD);
			schedule();

			/* We're back.  Did the debugger cancel the sig?  */
			if (!(signr = current->exit_code))
				continue;
			current->exit_code = 0;

			/* The debugger continued.  Ignore SIGSTOP.  */
			if (signr == SIGSTOP)
				continue;

			/* Update the siginfo structure.  Is this good?  */
			if (signr != info.si_signo) {
				info.si_signo = signr;
				info.si_errno = 0;
				info.si_code = SI_USER;
				info.si_pid = current->p_pptr->pid;
				info.si_uid = current->p_pptr->uid;
			}

			/* If the (new) signal is now blocked, requeue it.  */
			if (sigismember(&current->blocked, signr)) {
				send_sig_info(signr, &info, current);
				continue;
			}
		}

		ka = &current->sig->action[signr-1];
		if (ka->sa.sa_handler == SIG_IGN) {
			if (signr != SIGCHLD)
				continue;
			/* Check for SIGCHLD: it's special.  */
			while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
				/* nothing */;
			continue;
		}

		if (ka->sa.sa_handler == SIG_DFL) {
			int exit_code = signr;

			/* Init gets no signals it doesn't want.  */
			if (current->pid == 1)
				continue;

			switch (signr) {
			case SIGCONT: case SIGCHLD: case SIGWINCH:
				continue;

			case SIGTSTP: case SIGTTIN: case SIGTTOU:
				if (is_orphaned_pgrp(current->pgrp))
					continue;
				/* FALLTHRU */

			case SIGSTOP:
				current->state = TASK_STOPPED;
				current->exit_code = signr;
				if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
					notify_parent(current, SIGCHLD);
				schedule();
				continue;

			case SIGQUIT: case SIGILL: case SIGTRAP:
			case SIGABRT: case SIGFPE: case SIGSEGV:
			case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
				if (do_coredump(signr, regs))
					exit_code |= 0x80;
				/* FALLTHRU */

			default:
				lock_kernel();
				sigaddset(&current->signal, signr);
				recalc_sigpending(current);
				current->flags |= PF_SIGNALED;
				do_exit(exit_code);
				/* NOTREACHED */
			}
		}

		if ( (ka->sa.sa_flags & SA_ONSTACK)
		     && (! on_sig_stack(regs->gpr[1])))
			newsp = (current->sas_ss_sp + current->sas_ss_size);
		else
			newsp = regs->gpr[1];
		newsp = frame = newsp - sizeof(struct sigregs);

		/* Whee!  Actually deliver the signal.  */
		handle_signal(signr, ka, &info, oldset, regs, &newsp, frame);
	}

	if (regs->trap == 0x0C00 /* System Call! */ &&
	    ((int)regs->result == -ERESTARTNOHAND ||
	     (int)regs->result == -ERESTARTSYS ||
	     (int)regs->result == -ERESTARTNOINTR)) {
		regs->gpr[3] = regs->orig_gpr3;
		regs->nip -= 4;		/* Back up & retry system call */
		regs->result = 0;
	}

	if (newsp == frame)
		return 0;		/* no signals delivered */

	if (ka->sa.sa_flags & SA_SIGINFO)
		setup_rt_frame(regs, (struct sigregs *) frame, newsp);
	else
		setup_frame(regs, (struct sigregs *) frame, newsp);
	return 1;
}