1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1991, 1992  Linus Torvalds
7 * Copyright (C) 1994 - 2000  Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 */
10#include <linux/cache.h>
11#include <linux/sched.h>
12#include <linux/mm.h>
13#include <linux/personality.h>
14#include <linux/smp.h>
15#include <linux/kernel.h>
16#include <linux/signal.h>
17#include <linux/errno.h>
18#include <linux/wait.h>
19#include <linux/ptrace.h>
20#include <linux/unistd.h>
21#include <linux/compiler.h>
22#include <linux/uaccess.h>
23
24#include <asm/abi.h>
25#include <asm/asm.h>
26#include <linux/bitops.h>
27#include <asm/cacheflush.h>
28#include <asm/fpu.h>
29#include <asm/sim.h>
30#include <asm/ucontext.h>
31#include <asm/cpu-features.h>
32#include <asm/war.h>
33
34#include "signal-common.h"
35
36/*
37 * Horribly complicated - with the bloody RM9000 workarounds enabled
38 * the signal trampolines is moving to the end of the structure so we can
39 * increase the alignment without breaking software compatibility.
40 */
41#if ICACHE_REFILLS_WORKAROUND_WAR == 0
42
43struct sigframe {
44	u32 sf_ass[4];		/* argument save space for o32 */
45	u32 sf_code[2];		/* signal trampoline */
46	struct sigcontext sf_sc;
47	sigset_t sf_mask;
48};
49
50struct rt_sigframe {
51	u32 rs_ass[4];		/* argument save space for o32 */
52	u32 rs_code[2];		/* signal trampoline */
53	struct siginfo rs_info;
54	struct ucontext rs_uc;
55};
56
57#else
58
59struct sigframe {
60	u32 sf_ass[4];			/* argument save space for o32 */
61	u32 sf_pad[2];
62	struct sigcontext sf_sc;	/* hw context */
63	sigset_t sf_mask;
64	u32 sf_code[8] ____cacheline_aligned;	/* signal trampoline */
65};
66
67struct rt_sigframe {
68	u32 rs_ass[4];			/* argument save space for o32 */
69	u32 rs_pad[2];
70	struct siginfo rs_info;
71	struct ucontext rs_uc;
72	u32 rs_code[8] ____cacheline_aligned;	/* signal trampoline */
73};
74
75#endif
76
77/*
78 * Helper routines
79 */
80static int protected_save_fp_context(struct sigcontext __user *sc)
81{
82	int err;
83	while (1) {
84		lock_fpu_owner();
85		own_fpu_inatomic(1);
86		err = save_fp_context(sc); /* this might fail */
87		unlock_fpu_owner();
88		if (likely(!err))
89			break;
90		/* touch the sigcontext and try again */
91		err = __put_user(0, &sc->sc_fpregs[0]) |
92			__put_user(0, &sc->sc_fpregs[31]) |
93			__put_user(0, &sc->sc_fpc_csr);
94		if (err)
95			break;	/* really bad sigcontext */
96	}
97	return err;
98}
99
100static int protected_restore_fp_context(struct sigcontext __user *sc)
101{
102	int err, tmp;
103	while (1) {
104		lock_fpu_owner();
105		own_fpu_inatomic(0);
106		err = restore_fp_context(sc); /* this might fail */
107		unlock_fpu_owner();
108		if (likely(!err))
109			break;
110		/* touch the sigcontext and try again */
111		err = __get_user(tmp, &sc->sc_fpregs[0]) |
112			__get_user(tmp, &sc->sc_fpregs[31]) |
113			__get_user(tmp, &sc->sc_fpc_csr);
114		if (err)
115			break;	/* really bad sigcontext */
116	}
117	return err;
118}
119
120int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
121{
122	int err = 0;
123	int i;
124	unsigned int used_math;
125
126	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
127
128	err |= __put_user(0, &sc->sc_regs[0]);
129	for (i = 1; i < 32; i++)
130		err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
131
132#ifdef CONFIG_CPU_HAS_SMARTMIPS
133	err |= __put_user(regs->acx, &sc->sc_acx);
134#endif
135	err |= __put_user(regs->hi, &sc->sc_mdhi);
136	err |= __put_user(regs->lo, &sc->sc_mdlo);
137	if (cpu_has_dsp) {
138		err |= __put_user(mfhi1(), &sc->sc_hi1);
139		err |= __put_user(mflo1(), &sc->sc_lo1);
140		err |= __put_user(mfhi2(), &sc->sc_hi2);
141		err |= __put_user(mflo2(), &sc->sc_lo2);
142		err |= __put_user(mfhi3(), &sc->sc_hi3);
143		err |= __put_user(mflo3(), &sc->sc_lo3);
144		err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
145	}
146
147	used_math = !!used_math();
148	err |= __put_user(used_math, &sc->sc_used_math);
149
150	if (used_math) {
151		/*
152		 * Save FPU state to signal context. Signal handler
153		 * will "inherit" current FPU state.
154		 */
155		err |= protected_save_fp_context(sc);
156	}
157	return err;
158}
159
160int fpcsr_pending(unsigned int __user *fpcsr)
161{
162	int err, sig = 0;
163	unsigned int csr, enabled;
164
165	err = __get_user(csr, fpcsr);
166	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
167	/*
168	 * If the signal handler set some FPU exceptions, clear it and
169	 * send SIGFPE.
170	 */
171	if (csr & enabled) {
172		csr &= ~enabled;
173		err |= __put_user(csr, fpcsr);
174		sig = SIGFPE;
175	}
176	return err ?: sig;
177}
178
179static int
180check_and_restore_fp_context(struct sigcontext __user *sc)
181{
182	int err, sig;
183
184	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
185	if (err > 0)
186		err = 0;
187	err |= protected_restore_fp_context(sc);
188	return err ?: sig;
189}
190
191int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
192{
193	unsigned int used_math;
194	unsigned long treg;
195	int err = 0;
196	int i;
197
198	/* Always make any pending restarted system calls return -EINTR */
199	current_thread_info()->restart_block.fn = do_no_restart_syscall;
200
201	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
202
203#ifdef CONFIG_CPU_HAS_SMARTMIPS
204	err |= __get_user(regs->acx, &sc->sc_acx);
205#endif
206	err |= __get_user(regs->hi, &sc->sc_mdhi);
207	err |= __get_user(regs->lo, &sc->sc_mdlo);
208	if (cpu_has_dsp) {
209		err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
210		err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
211		err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
212		err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
213		err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
214		err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
215		err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
216	}
217
218	for (i = 1; i < 32; i++)
219		err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
220
221	err |= __get_user(used_math, &sc->sc_used_math);
222	conditional_used_math(used_math);
223
224	if (used_math) {
225		/* restore fpu context if we have used it before */
226		if (!err)
227			err = check_and_restore_fp_context(sc);
228	} else {
229		/* signal handler may have used FPU.  Give it up. */
230		lose_fpu(0);
231	}
232
233	return err;
234}
235
236void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
237			  size_t frame_size)
238{
239	unsigned long sp;
240
241	/* Default to using normal stack */
242	sp = regs->regs[29];
243
244	/*
245	 * FPU emulator may have it's own trampoline active just
246	 * above the user stack, 16-bytes before the next lowest
247	 * 16 byte boundary.  Try to avoid trashing it.
248	 */
249	sp -= 32;
250
251	/* This is the X/Open sanctioned signal stack switching.  */
252	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
253		sp = current->sas_ss_sp + current->sas_ss_size;
254
255	return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
256}
257
258int install_sigtramp(unsigned int __user *tramp, unsigned int syscall)
259{
260	int err;
261
262	/*
263	 * Set up the return code ...
264	 *
265	 *         li      v0, __NR__foo_sigreturn
266	 *         syscall
267	 */
268
269	err = __put_user(0x24020000 + syscall, tramp + 0);
270	err |= __put_user(0x0000000c         , tramp + 1);
271	if (ICACHE_REFILLS_WORKAROUND_WAR) {
272		err |= __put_user(0, tramp + 2);
273		err |= __put_user(0, tramp + 3);
274		err |= __put_user(0, tramp + 4);
275		err |= __put_user(0, tramp + 5);
276		err |= __put_user(0, tramp + 6);
277		err |= __put_user(0, tramp + 7);
278	}
279	flush_cache_sigtramp((unsigned long) tramp);
280
281	return err;
282}
283
284/*
285 * Atomically swap in the new signal mask, and wait for a signal.
286 */
287
288#ifdef CONFIG_TRAD_SIGNALS
289asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
290{
291	sigset_t newset;
292	sigset_t __user *uset;
293
294	uset = (sigset_t __user *) regs.regs[4];
295	if (copy_from_user(&newset, uset, sizeof(sigset_t)))
296		return -EFAULT;
297	sigdelsetmask(&newset, ~_BLOCKABLE);
298
299	spin_lock_irq(&current->sighand->siglock);
300	current->saved_sigmask = current->blocked;
301	current->blocked = newset;
302	recalc_sigpending();
303	spin_unlock_irq(&current->sighand->siglock);
304
305	current->state = TASK_INTERRUPTIBLE;
306	schedule();
307	set_thread_flag(TIF_RESTORE_SIGMASK);
308	return -ERESTARTNOHAND;
309}
310#endif
311
312asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
313{
314	sigset_t newset;
315	sigset_t __user *unewset;
316	size_t sigsetsize;
317
318	sigsetsize = regs.regs[5];
319	if (sigsetsize != sizeof(sigset_t))
320		return -EINVAL;
321
322	unewset = (sigset_t __user *) regs.regs[4];
323	if (copy_from_user(&newset, unewset, sizeof(newset)))
324		return -EFAULT;
325	sigdelsetmask(&newset, ~_BLOCKABLE);
326
327	spin_lock_irq(&current->sighand->siglock);
328	current->saved_sigmask = current->blocked;
329	current->blocked = newset;
330	recalc_sigpending();
331	spin_unlock_irq(&current->sighand->siglock);
332
333	current->state = TASK_INTERRUPTIBLE;
334	schedule();
335	set_thread_flag(TIF_RESTORE_SIGMASK);
336	return -ERESTARTNOHAND;
337}
338
339#ifdef CONFIG_TRAD_SIGNALS
340asmlinkage int sys_sigaction(int sig, const struct sigaction __user *act,
341	struct sigaction __user *oact)
342{
343	struct k_sigaction new_ka, old_ka;
344	int ret;
345	int err = 0;
346
347	if (act) {
348		old_sigset_t mask;
349
350		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
351			return -EFAULT;
352		err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
353		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
354		err |= __get_user(mask, &act->sa_mask.sig[0]);
355		if (err)
356			return -EFAULT;
357
358		siginitset(&new_ka.sa.sa_mask, mask);
359	}
360
361	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
362
363	if (!ret && oact) {
364		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
365			return -EFAULT;
366		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
367		err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
368		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
369		err |= __put_user(0, &oact->sa_mask.sig[1]);
370		err |= __put_user(0, &oact->sa_mask.sig[2]);
371		err |= __put_user(0, &oact->sa_mask.sig[3]);
372		if (err)
373			return -EFAULT;
374	}
375
376	return ret;
377}
378#endif
379
380asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
381{
382	const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
383	stack_t __user *uoss = (stack_t __user *) regs.regs[5];
384	unsigned long usp = regs.regs[29];
385
386	return do_sigaltstack(uss, uoss, usp);
387}
388
389#ifdef CONFIG_TRAD_SIGNALS
390asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
391{
392	struct sigframe __user *frame;
393	sigset_t blocked;
394	int sig;
395
396	frame = (struct sigframe __user *) regs.regs[29];
397	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
398		goto badframe;
399	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
400		goto badframe;
401
402	sigdelsetmask(&blocked, ~_BLOCKABLE);
403	spin_lock_irq(&current->sighand->siglock);
404	current->blocked = blocked;
405	recalc_sigpending();
406	spin_unlock_irq(&current->sighand->siglock);
407
408	sig = restore_sigcontext(&regs, &frame->sf_sc);
409	if (sig < 0)
410		goto badframe;
411	else if (sig)
412		force_sig(sig, current);
413
414	/*
415	 * Don't let your children do this ...
416	 */
417	__asm__ __volatile__(
418		"move\t$29, %0\n\t"
419		"j\tsyscall_exit"
420		:/* no outputs */
421		:"r" (&regs));
422	/* Unreached */
423
424badframe:
425	force_sig(SIGSEGV, current);
426}
427#endif /* CONFIG_TRAD_SIGNALS */
428
429asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
430{
431	struct rt_sigframe __user *frame;
432	sigset_t set;
433	stack_t st;
434	int sig;
435
436	frame = (struct rt_sigframe __user *) regs.regs[29];
437	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
438		goto badframe;
439	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
440		goto badframe;
441
442	sigdelsetmask(&set, ~_BLOCKABLE);
443	spin_lock_irq(&current->sighand->siglock);
444	current->blocked = set;
445	recalc_sigpending();
446	spin_unlock_irq(&current->sighand->siglock);
447
448	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
449	if (sig < 0)
450		goto badframe;
451	else if (sig)
452		force_sig(sig, current);
453
454	if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
455		goto badframe;
456	/* It is more difficult to avoid calling this function than to
457	   call it and ignore errors.  */
458	do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
459
460	/*
461	 * Don't let your children do this ...
462	 */
463	__asm__ __volatile__(
464		"move\t$29, %0\n\t"
465		"j\tsyscall_exit"
466		:/* no outputs */
467		:"r" (&regs));
468	/* Unreached */
469
470badframe:
471	force_sig(SIGSEGV, current);
472}
473
474#ifdef CONFIG_TRAD_SIGNALS
475static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
476	int signr, sigset_t *set)
477{
478	struct sigframe __user *frame;
479	int err = 0;
480
481	frame = get_sigframe(ka, regs, sizeof(*frame));
482	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
483		goto give_sigsegv;
484
485	err |= install_sigtramp(frame->sf_code, __NR_sigreturn);
486
487	err |= setup_sigcontext(regs, &frame->sf_sc);
488	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
489	if (err)
490		goto give_sigsegv;
491
492	/*
493	 * Arguments to signal handler:
494	 *
495	 *   a0 = signal number
496	 *   a1 = 0 (should be cause)
497	 *   a2 = pointer to struct sigcontext
498	 *
499	 * $25 and c0_epc point to the signal handler, $29 points to the
500	 * struct sigframe.
501	 */
502	regs->regs[ 4] = signr;
503	regs->regs[ 5] = 0;
504	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
505	regs->regs[29] = (unsigned long) frame;
506	regs->regs[31] = (unsigned long) frame->sf_code;
507	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
508
509	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
510	       current->comm, current->pid,
511	       frame, regs->cp0_epc, regs->regs[31]);
512	return 0;
513
514give_sigsegv:
515	force_sigsegv(signr, current);
516	return -EFAULT;
517}
518#endif
519
520static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
521	int signr, sigset_t *set, siginfo_t *info)
522{
523	struct rt_sigframe __user *frame;
524	int err = 0;
525
526	frame = get_sigframe(ka, regs, sizeof(*frame));
527	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
528		goto give_sigsegv;
529
530	err |= install_sigtramp(frame->rs_code, __NR_rt_sigreturn);
531
532	/* Create siginfo.  */
533	err |= copy_siginfo_to_user(&frame->rs_info, info);
534
535	/* Create the ucontext.  */
536	err |= __put_user(0, &frame->rs_uc.uc_flags);
537	err |= __put_user(NULL, &frame->rs_uc.uc_link);
538	err |= __put_user((void __user *)current->sas_ss_sp,
539	                  &frame->rs_uc.uc_stack.ss_sp);
540	err |= __put_user(sas_ss_flags(regs->regs[29]),
541	                  &frame->rs_uc.uc_stack.ss_flags);
542	err |= __put_user(current->sas_ss_size,
543	                  &frame->rs_uc.uc_stack.ss_size);
544	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
545	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
546
547	if (err)
548		goto give_sigsegv;
549
550	/*
551	 * Arguments to signal handler:
552	 *
553	 *   a0 = signal number
554	 *   a1 = 0 (should be cause)
555	 *   a2 = pointer to ucontext
556	 *
557	 * $25 and c0_epc point to the signal handler, $29 points to
558	 * the struct rt_sigframe.
559	 */
560	regs->regs[ 4] = signr;
561	regs->regs[ 5] = (unsigned long) &frame->rs_info;
562	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
563	regs->regs[29] = (unsigned long) frame;
564	regs->regs[31] = (unsigned long) frame->rs_code;
565	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
566
567	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
568	       current->comm, current->pid,
569	       frame, regs->cp0_epc, regs->regs[31]);
570
571	return 0;
572
573give_sigsegv:
574	force_sigsegv(signr, current);
575	return -EFAULT;
576}
577
578struct mips_abi mips_abi = {
579#ifdef CONFIG_TRAD_SIGNALS
580	.setup_frame	= setup_frame,
581#endif
582	.setup_rt_frame	= setup_rt_frame,
583	.restart	= __NR_restart_syscall
584};
585
586static int handle_signal(unsigned long sig, siginfo_t *info,
587	struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
588{
589	int ret;
590
591	switch(regs->regs[0]) {
592	case ERESTART_RESTARTBLOCK:
593	case ERESTARTNOHAND:
594		regs->regs[2] = EINTR;
595		break;
596	case ERESTARTSYS:
597		if (!(ka->sa.sa_flags & SA_RESTART)) {
598			regs->regs[2] = EINTR;
599			break;
600		}
601	/* fallthrough */
602	case ERESTARTNOINTR:		/* Userland will reload $v0.  */
603		regs->regs[7] = regs->regs[26];
604		regs->cp0_epc -= 8;
605	}
606
607	regs->regs[0] = 0;		/* Don't deal with this again.  */
608
609	if (sig_uses_siginfo(ka))
610		ret = current->thread.abi->setup_rt_frame(ka, regs, sig, oldset, info);
611	else
612		ret = current->thread.abi->setup_frame(ka, regs, sig, oldset);
613
614	spin_lock_irq(&current->sighand->siglock);
615	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
616	if (!(ka->sa.sa_flags & SA_NODEFER))
617		sigaddset(&current->blocked,sig);
618	recalc_sigpending();
619	spin_unlock_irq(&current->sighand->siglock);
620
621	return ret;
622}
623
624static void do_signal(struct pt_regs *regs)
625{
626	struct k_sigaction ka;
627	sigset_t *oldset;
628	siginfo_t info;
629	int signr;
630
631	/*
632	 * We want the common case to go fast, which is why we may in certain
633	 * cases get here from kernel mode. Just return without doing anything
634	 * if so.
635	 */
636	if (!user_mode(regs))
637		return;
638
639	if (test_thread_flag(TIF_RESTORE_SIGMASK))
640		oldset = &current->saved_sigmask;
641	else
642		oldset = &current->blocked;
643
644	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
645	if (signr > 0) {
646		/* Whee!  Actually deliver the signal.  */
647		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
648			/*
649			 * A signal was successfully delivered; the saved
650			 * sigmask will have been stored in the signal frame,
651			 * and will be restored by sigreturn, so we can simply
652			 * clear the TIF_RESTORE_SIGMASK flag.
653			 */
654			if (test_thread_flag(TIF_RESTORE_SIGMASK))
655				clear_thread_flag(TIF_RESTORE_SIGMASK);
656		}
657
658		return;
659	}
660
661	/*
662	 * Who's code doesn't conform to the restartable syscall convention
663	 * dies here!!!  The li instruction, a single machine instruction,
664	 * must directly be followed by the syscall instruction.
665	 */
666	if (regs->regs[0]) {
667		if (regs->regs[2] == ERESTARTNOHAND ||
668		    regs->regs[2] == ERESTARTSYS ||
669		    regs->regs[2] == ERESTARTNOINTR) {
670			regs->regs[7] = regs->regs[26];
671			regs->cp0_epc -= 8;
672		}
673		if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
674			regs->regs[2] = current->thread.abi->restart;
675			regs->regs[7] = regs->regs[26];
676			regs->cp0_epc -= 4;
677		}
678		regs->regs[0] = 0;	/* Don't deal with this again.  */
679	}
680
681	/*
682	 * If there's no signal to deliver, we just put the saved sigmask
683	 * back
684	 */
685	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
686		clear_thread_flag(TIF_RESTORE_SIGMASK);
687		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
688	}
689}
690
691/*
692 * notification of userspace execution resumption
693 * - triggered by the TIF_WORK_MASK flags
694 */
695asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
696	__u32 thread_info_flags)
697{
698	/* deal with pending signal delivery */
699	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
700		do_signal(regs);
701}
702