summaryrefslogtreecommitdiffstats
path: root/arch/xtensa/kernel/signal.c
blob: e252b61e45a5b36ff6d1ddadbe1aeb172dc3a359 (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
// TODO coprocessor stuff
/*
 *  linux/arch/xtensa/kernel/signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *
 *  Joe Taylor <joe@tensilica.com>
 *  Chris Zankel <chris@zankel.net>
 *
 *
 *
 */

#include <xtensa/config/core.h>
#include <xtensa/hal.h>
#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/personality.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>

#define DEBUG_SIG  0

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

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

extern struct task_struct *coproc_owners[];


/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */

int sys_sigsuspend(struct pt_regs *regs)
{
	old_sigset_t mask = (old_sigset_t) regs->areg[3];
	sigset_t saveset;

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

	regs->areg[2] = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(regs, &saveset))
			return -EINTR;
	}
}

asmlinkage int
sys_rt_sigsuspend(struct pt_regs *regs)
{
	sigset_t *unewset = (sigset_t *) regs->areg[4];
	size_t sigsetsize = (size_t) regs->areg[3];
	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->sighand->siglock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	regs->areg[2] = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(regs, &saveset))
			return -EINTR;
	}
}

asmlinkage 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;
}

asmlinkage int
sys_sigaltstack(struct pt_regs *regs)
{
	const stack_t *uss = (stack_t *) regs->areg[4];
	stack_t *uoss = (stack_t *) regs->areg[3];

	if (regs->depc > 64)
		panic ("Double exception sys_sigreturn\n");


	return do_sigaltstack(uss, uoss, regs->areg[1]);
}


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

struct sigframe
{
	struct sigcontext sc;
	struct _cpstate cpstate;
	unsigned long extramask[_NSIG_WORDS-1];
	unsigned char retcode[6];
	unsigned int reserved[4]; /* Reserved area for chaining */
	unsigned int window[4]; /* Window of 4 registers for initial context */
};

struct rt_sigframe
{
	struct siginfo info;
	struct ucontext uc;
	struct _cpstate cpstate;
	unsigned char retcode[6];
	unsigned int reserved[4]; /* Reserved area for chaining */
	unsigned int window[4]; /* Window of 4 registers for initial context */
};

extern void release_all_cp (struct task_struct *);


// FIXME restore_cpextra
static inline int
restore_cpextra (struct _cpstate *buf)
{
#if 0
	/* The signal handler may have used coprocessors in which
	 * case they are still enabled.  We disable them to force a
	 * reloading of the original task's CP state by the lazy
	 * context-switching mechanisms of CP exception handling.
	 * Also, we essentially discard any coprocessor state that the
	 * signal handler created. */

	struct task_struct *tsk = current;
	release_all_cp(tsk);
	return __copy_from_user(tsk->thread.cpextra, buf, XTENSA_CP_EXTRA_SIZE);
#endif
	return 0;
}

/* Note: We don't copy double exception 'tregs', we have to finish double exc. first before we return to signal handler! This dbl.exc.handler might cause another double exception, but I think we are fine as the situation is the same as if we had returned to the signal handerl and got an interrupt immediately...
 */


static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
{
	struct thread_struct *thread;
	unsigned int err = 0;
	unsigned long ps;
	struct _cpstate *buf;

#define COPY(x)	err |= __get_user(regs->x, &sc->sc_##x)
	COPY(pc);
	COPY(depc);
	COPY(wmask);
	COPY(lbeg);
	COPY(lend);
	COPY(lcount);
	COPY(sar);
	COPY(windowbase);
	COPY(windowstart);
#undef COPY

	/* For PS, restore only PS.CALLINC.
	 * Assume that all other bits are either the same as for the signal
	 * handler, or the user mode value doesn't matter (e.g. PS.OWB).
	 */
	err |= __get_user(ps, &sc->sc_ps);
	regs->ps = (regs->ps & ~XCHAL_PS_CALLINC_MASK)
		| (ps & XCHAL_PS_CALLINC_MASK);

	/* Additional corruption checks */

	if ((regs->windowbase >= (XCHAL_NUM_AREGS/4))
	|| ((regs->windowstart & ~((1<<(XCHAL_NUM_AREGS/4)) - 1)) != 0) )
		err = 1;
	if ((regs->lcount > 0)
	&& ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) )
		err = 1;

	/* Restore extended register state.
	 * See struct thread_struct in processor.h.
	 */
	thread = &current->thread;

	err |= __copy_from_user (regs->areg, sc->sc_areg, XCHAL_NUM_AREGS*4);
	err |= __get_user(buf, &sc->sc_cpstate);
	if (buf) {
		if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
			goto badframe;
		err |= restore_cpextra(buf);
	}

	regs->syscall = -1;		/* disable syscall checks */
	return err;

badframe:
	return 1;
}

static inline void
flush_my_cpstate(struct task_struct *tsk)
{
	unsigned long flags;
	local_irq_save(flags);

#if 0	// FIXME
	for (i = 0; i < XCHAL_CP_NUM; i++) {
		if (tsk == coproc_owners[i]) {
			xthal_validate_cp(i);
			xthal_save_cpregs(tsk->thread.cpregs_ptr[i], i);

			/* Invalidate and "disown" the cp to allow
			 * callers the chance to reset cp state in the
			 * task_struct. */

			xthal_invalidate_cp(i);
			coproc_owners[i] = 0;
		}
	}
#endif
	local_irq_restore(flags);
}

/* Return codes:
	0:  nothing saved
	1:  stuff to save, successful
       -1:  stuff to save, error happened
*/
static int
save_cpextra (struct _cpstate *buf)
{
#if (XCHAL_EXTRA_SA_SIZE == 0) && (XCHAL_CP_NUM == 0)
	return 0;
#else

	/* FIXME: If a task has never used a coprocessor, there is
	 * no need to save and restore anything.  Tracking this
	 * information would allow us to optimize this section.
	 * Perhaps we can use current->used_math or (current->flags &
	 * PF_USEDFPU) or define a new field in the thread
	 * structure. */

	/* We flush any live, task-owned cp state to the task_struct,
	 * then copy it all to the sigframe.  Then we clear all
	 * cp/extra state in the task_struct, effectively
	 * clearing/resetting all cp/extra state for the signal
	 * handler (cp-exception handling will load these new values
	 * into the cp/extra registers.)  This step is important for
	 * things like a floating-point cp, where the OS must reset
	 * the FCR to the default rounding mode. */

	int err = 0;
	struct task_struct *tsk = current;

	flush_my_cpstate(tsk);
	/* Note that we just copy everything: 'extra' and 'cp' state together.*/
	err |= __copy_to_user(buf, tsk->thread.cp_save, XTENSA_CP_EXTRA_SIZE);
	memset(tsk->thread.cp_save, 0, XTENSA_CP_EXTRA_SIZE);

#if (XTENSA_CP_EXTRA_SIZE == 0)
#error Sanity check on memset above, cpextra_size should not be zero.
#endif

	return err ? -1 : 1;
#endif
}

static int
setup_sigcontext(struct sigcontext *sc, struct _cpstate *cpstate,
		 struct pt_regs *regs, unsigned long mask)
{
	struct thread_struct *thread;
	int err = 0;

//printk("setup_sigcontext\n");
#define COPY(x)	err |= __put_user(regs->x, &sc->sc_##x)
	COPY(pc);
	COPY(ps);
	COPY(depc);
	COPY(wmask);
	COPY(lbeg);
	COPY(lend);
	COPY(lcount);
	COPY(sar);
	COPY(windowbase);
	COPY(windowstart);
#undef COPY

	/* Save extended register state.
	 * See struct thread_struct in processor.h.
	 */
	thread = &current->thread;
	err |= __copy_to_user (sc->sc_areg, regs->areg, XCHAL_NUM_AREGS * 4);
	err |= save_cpextra(cpstate);
	err |= __put_user(err ? NULL : cpstate, &sc->sc_cpstate);
	/* non-iBCS2 extensions.. */
	err |= __put_user(mask, &sc->oldmask);

	return err;
}

asmlinkage int sys_sigreturn(struct pt_regs *regs)
{
	struct sigframe *frame = (struct sigframe *)regs->areg[1];
	sigset_t set;
	if (regs->depc > 64)
		panic ("Double exception sys_sigreturn\n");

	if (verify_area(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;

	sigdelsetmask(&set, ~_BLOCKABLE);

	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext(regs, &frame->sc))
		goto badframe;
	return regs->areg[2];

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_sigframe *frame = (struct rt_sigframe *)regs->areg[1];
	sigset_t set;
	stack_t st;
	int ret;
	if (regs->depc > 64)
	{
		printk("!!!!!!! DEPC !!!!!!!\n");
		return 0;
	}

	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;

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

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
		goto badframe;
	ret = regs->areg[2];

	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
		goto badframe;
	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	do_sigaltstack(&st, NULL, regs->areg[1]);

	return ret;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

/*
 * Set up a signal frame.
 */

/*
 * Determine which stack to use..
 */
static inline void *
get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
{
	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp))
		sp = current->sas_ss_sp + current->sas_ss_size;

	return (void *)((sp - frame_size) & -16ul);
}

#define USE_SIGRETURN		0
#define USE_RT_SIGRETURN	1

static int
gen_return_code(unsigned char *codemem, unsigned int use_rt_sigreturn)
{
	unsigned int retcall;
	int err = 0;

#if 0
	/* Ignoring SA_RESTORER for now; it's supposed to be obsolete,
	 * and the xtensa glibc doesn't use it.
	 */
	if (ka->sa.sa_flags & SA_RESTORER) {
		regs->pr = (unsigned long) ka->sa.sa_restorer;
	} else
#endif /* 0 */
	{

#if (__NR_sigreturn > 255) || (__NR_rt_sigreturn > 255)

/* The 12-bit immediate is really split up within the 24-bit MOVI
 * instruction.  As long as the above system call numbers fit within
 * 8-bits, the following code works fine. See the Xtensa ISA for
 * details.
 */

#error Generating the MOVI instruction below breaks!
#endif

		retcall = use_rt_sigreturn ? __NR_rt_sigreturn : __NR_sigreturn;

#ifdef __XTENSA_EB__   /* Big Endian version */
		/* Generate instruction:  MOVI a2, retcall */
		err |= __put_user(0x22, &codemem[0]);
		err |= __put_user(0x0a, &codemem[1]);
		err |= __put_user(retcall, &codemem[2]);
		/* Generate instruction:  SYSCALL */
		err |= __put_user(0x00, &codemem[3]);
		err |= __put_user(0x05, &codemem[4]);
		err |= __put_user(0x00, &codemem[5]);

#elif defined __XTENSA_EL__   /* Little Endian version */
		/* Generate instruction:  MOVI a2, retcall */
		err |= __put_user(0x22, &codemem[0]);
		err |= __put_user(0xa0, &codemem[1]);
		err |= __put_user(retcall, &codemem[2]);
		/* Generate instruction:  SYSCALL */
		err |= __put_user(0x00, &codemem[3]);
		err |= __put_user(0x50, &codemem[4]);
		err |= __put_user(0x00, &codemem[5]);
#else
#error Must use compiler for Xtensa processors.
#endif
	}

	/* Flush generated code out of the data cache */

	if (err == 0)
		__flush_invalidate_cache_range((unsigned long)codemem, 6UL);

	return err;
}

static void
set_thread_state(struct pt_regs *regs, void *stack, unsigned char *retaddr,
	void *handler, unsigned long arg1, void *arg2, void *arg3)
{
	/* Set up registers for signal handler */
	start_thread(regs, (unsigned long) handler, (unsigned long) stack);

	/* Set up a stack frame for a call4
	 * Note: PS.CALLINC is set to one by start_thread
	 */
	regs->areg[4] = (((unsigned long) retaddr) & 0x3fffffff) | 0x40000000;
	regs->areg[6] = arg1;
	regs->areg[7] = (unsigned long) arg2;
	regs->areg[8] = (unsigned long) arg3;
}

static void setup_frame(int sig, struct k_sigaction *ka,
			sigset_t *set, struct pt_regs *regs)
{
	struct sigframe *frame;
	int err = 0;
	int signal;

	frame = get_sigframe(ka, regs->areg[1], sizeof(*frame));
	if (regs->depc > 64)
	{
		printk("!!!!!!! DEPC !!!!!!!\n");
		return;
	}


	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= setup_sigcontext(&frame->sc, &frame->cpstate, regs, set->sig[0]);

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

	/* Create sys_sigreturn syscall in stack frame */
	err |= gen_return_code(frame->retcode, USE_SIGRETURN);

	if (err)
		goto give_sigsegv;

	/* Create signal handler execution context.
	 * Return context not modified until this point.
	 */
	set_thread_state(regs, frame, frame->retcode,
		ka->sa.sa_handler, signal, &frame->sc, NULL);

	/* Set access mode to USER_DS.  Nomenclature is outdated, but
	 * functionality is used in uaccess.h
	 */
	set_fs(USER_DS);


#if DEBUG_SIG
	printk("SIG deliver (%s:%d): signal=%d sp=%p pc=%08x\n",
		current->comm, current->pid, signal, frame, regs->pc);
#endif

	return;

give_sigsegv:
	if (sig == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
}

static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe *frame;
	int err = 0;
	int signal;

	frame = get_sigframe(ka, regs->areg[1], sizeof(*frame));
	if (regs->depc > 64)
		panic ("Double exception sys_sigreturn\n");

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= copy_siginfo_to_user(&frame->info, info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user((void *)current->sas_ss_sp,
			  &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->areg[1]),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->cpstate,
			        regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Create sys_rt_sigreturn syscall in stack frame */
	err |= gen_return_code(frame->retcode, USE_RT_SIGRETURN);

	if (err)
		goto give_sigsegv;

	/* Create signal handler execution context.
	 * Return context not modified until this point.
	 */
	set_thread_state(regs, frame, frame->retcode,
		ka->sa.sa_handler, signal, &frame->info, &frame->uc);

	/* Set access mode to USER_DS.  Nomenclature is outdated, but
	 * functionality is used in uaccess.h
	 */
	set_fs(USER_DS);

#if DEBUG_SIG
	printk("SIG rt deliver (%s:%d): signal=%d sp=%p pc=%08x\n",
		current->comm, current->pid, signal, frame, regs->pc);
#endif

	return;

give_sigsegv:
	if (sig == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
}



/*
 * 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.
 *
 * Note that we go through the signals twice: once to check the signals that
 * the kernel can handle, and then we build all the user-level signal handling
 * stack-frames in one go after that.
 */
int do_signal(struct pt_regs *regs, sigset_t *oldset)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;

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

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	/* Are we from a system call? */
	if (regs->syscall >= 0) {
		/* If so, check system call restarting.. */
		switch (regs->areg[2]) {
			case ERESTARTNOHAND:
			case ERESTART_RESTARTBLOCK:
				regs->areg[2] = -EINTR;
				break;

			case ERESTARTSYS:
				if (!(ka.sa.sa_flags & SA_RESTART)) {
					regs->areg[2] = -EINTR;
					break;
				}
			/* fallthrough */
			case ERESTARTNOINTR:
				regs->areg[2] = regs->syscall;
				regs->pc -= 3;
		}
	}

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

	/* Whee!  Actually deliver the signal.  */

	/* Set up the stack frame */
	if (ka.sa.sa_flags & SA_SIGINFO)
		setup_rt_frame(signr, &ka, &info, oldset, regs);
	else
		setup_frame(signr, &ka, oldset, regs);

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

	spin_lock_irq(&current->sighand->siglock);
	sigorsets(&current->blocked, &current->blocked, &ka.sa.sa_mask);
	if (!(ka.sa.sa_flags & SA_NODEFER))
		sigaddset(&current->blocked, signr);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	return 1;
}
OpenPOWER on IntegriCloud