xref: /linux/arch/mips/kernel/signal.c (revision f2ee442115c9b6219083c019939a9cc0c9abb2f8)
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/irqflags.h>
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/personality.h>
15 #include <linux/smp.h>
16 #include <linux/kernel.h>
17 #include <linux/signal.h>
18 #include <linux/errno.h>
19 #include <linux/wait.h>
20 #include <linux/ptrace.h>
21 #include <linux/unistd.h>
22 #include <linux/compiler.h>
23 #include <linux/syscalls.h>
24 #include <linux/uaccess.h>
25 #include <linux/tracehook.h>
26 
27 #include <asm/abi.h>
28 #include <asm/asm.h>
29 #include <linux/bitops.h>
30 #include <asm/cacheflush.h>
31 #include <asm/fpu.h>
32 #include <asm/sim.h>
33 #include <asm/ucontext.h>
34 #include <asm/cpu-features.h>
35 #include <asm/war.h>
36 #include <asm/vdso.h>
37 
38 #include "signal-common.h"
39 
40 static int (*save_fp_context)(struct sigcontext __user *sc);
41 static int (*restore_fp_context)(struct sigcontext __user *sc);
42 
43 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
44 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
45 
46 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
47 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
48 
49 struct sigframe {
50 	u32 sf_ass[4];		/* argument save space for o32 */
51 	u32 sf_pad[2];		/* Was: signal trampoline */
52 	struct sigcontext sf_sc;
53 	sigset_t sf_mask;
54 };
55 
56 struct rt_sigframe {
57 	u32 rs_ass[4];		/* argument save space for o32 */
58 	u32 rs_pad[2];		/* Was: signal trampoline */
59 	struct siginfo rs_info;
60 	struct ucontext rs_uc;
61 };
62 
63 /*
64  * Helper routines
65  */
66 static int protected_save_fp_context(struct sigcontext __user *sc)
67 {
68 	int err;
69 	while (1) {
70 		lock_fpu_owner();
71 		own_fpu_inatomic(1);
72 		err = save_fp_context(sc); /* this might fail */
73 		unlock_fpu_owner();
74 		if (likely(!err))
75 			break;
76 		/* touch the sigcontext and try again */
77 		err = __put_user(0, &sc->sc_fpregs[0]) |
78 			__put_user(0, &sc->sc_fpregs[31]) |
79 			__put_user(0, &sc->sc_fpc_csr);
80 		if (err)
81 			break;	/* really bad sigcontext */
82 	}
83 	return err;
84 }
85 
86 static int protected_restore_fp_context(struct sigcontext __user *sc)
87 {
88 	int err, tmp __maybe_unused;
89 	while (1) {
90 		lock_fpu_owner();
91 		own_fpu_inatomic(0);
92 		err = restore_fp_context(sc); /* this might fail */
93 		unlock_fpu_owner();
94 		if (likely(!err))
95 			break;
96 		/* touch the sigcontext and try again */
97 		err = __get_user(tmp, &sc->sc_fpregs[0]) |
98 			__get_user(tmp, &sc->sc_fpregs[31]) |
99 			__get_user(tmp, &sc->sc_fpc_csr);
100 		if (err)
101 			break;	/* really bad sigcontext */
102 	}
103 	return err;
104 }
105 
106 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
107 {
108 	int err = 0;
109 	int i;
110 	unsigned int used_math;
111 
112 	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
113 
114 	err |= __put_user(0, &sc->sc_regs[0]);
115 	for (i = 1; i < 32; i++)
116 		err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
117 
118 #ifdef CONFIG_CPU_HAS_SMARTMIPS
119 	err |= __put_user(regs->acx, &sc->sc_acx);
120 #endif
121 	err |= __put_user(regs->hi, &sc->sc_mdhi);
122 	err |= __put_user(regs->lo, &sc->sc_mdlo);
123 	if (cpu_has_dsp) {
124 		err |= __put_user(mfhi1(), &sc->sc_hi1);
125 		err |= __put_user(mflo1(), &sc->sc_lo1);
126 		err |= __put_user(mfhi2(), &sc->sc_hi2);
127 		err |= __put_user(mflo2(), &sc->sc_lo2);
128 		err |= __put_user(mfhi3(), &sc->sc_hi3);
129 		err |= __put_user(mflo3(), &sc->sc_lo3);
130 		err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
131 	}
132 
133 	used_math = !!used_math();
134 	err |= __put_user(used_math, &sc->sc_used_math);
135 
136 	if (used_math) {
137 		/*
138 		 * Save FPU state to signal context. Signal handler
139 		 * will "inherit" current FPU state.
140 		 */
141 		err |= protected_save_fp_context(sc);
142 	}
143 	return err;
144 }
145 
146 int fpcsr_pending(unsigned int __user *fpcsr)
147 {
148 	int err, sig = 0;
149 	unsigned int csr, enabled;
150 
151 	err = __get_user(csr, fpcsr);
152 	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
153 	/*
154 	 * If the signal handler set some FPU exceptions, clear it and
155 	 * send SIGFPE.
156 	 */
157 	if (csr & enabled) {
158 		csr &= ~enabled;
159 		err |= __put_user(csr, fpcsr);
160 		sig = SIGFPE;
161 	}
162 	return err ?: sig;
163 }
164 
165 static int
166 check_and_restore_fp_context(struct sigcontext __user *sc)
167 {
168 	int err, sig;
169 
170 	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
171 	if (err > 0)
172 		err = 0;
173 	err |= protected_restore_fp_context(sc);
174 	return err ?: sig;
175 }
176 
177 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
178 {
179 	unsigned int used_math;
180 	unsigned long treg;
181 	int err = 0;
182 	int i;
183 
184 	/* Always make any pending restarted system calls return -EINTR */
185 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
186 
187 	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
188 
189 #ifdef CONFIG_CPU_HAS_SMARTMIPS
190 	err |= __get_user(regs->acx, &sc->sc_acx);
191 #endif
192 	err |= __get_user(regs->hi, &sc->sc_mdhi);
193 	err |= __get_user(regs->lo, &sc->sc_mdlo);
194 	if (cpu_has_dsp) {
195 		err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
196 		err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
197 		err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
198 		err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
199 		err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
200 		err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
201 		err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
202 	}
203 
204 	for (i = 1; i < 32; i++)
205 		err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
206 
207 	err |= __get_user(used_math, &sc->sc_used_math);
208 	conditional_used_math(used_math);
209 
210 	if (used_math) {
211 		/* restore fpu context if we have used it before */
212 		if (!err)
213 			err = check_and_restore_fp_context(sc);
214 	} else {
215 		/* signal handler may have used FPU.  Give it up. */
216 		lose_fpu(0);
217 	}
218 
219 	return err;
220 }
221 
222 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
223 			  size_t frame_size)
224 {
225 	unsigned long sp;
226 
227 	/* Default to using normal stack */
228 	sp = regs->regs[29];
229 
230 	/*
231 	 * FPU emulator may have it's own trampoline active just
232 	 * above the user stack, 16-bytes before the next lowest
233 	 * 16 byte boundary.  Try to avoid trashing it.
234 	 */
235 	sp -= 32;
236 
237 	/* This is the X/Open sanctioned signal stack switching.  */
238 	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
239 		sp = current->sas_ss_sp + current->sas_ss_size;
240 
241 	return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
242 }
243 
244 /*
245  * Atomically swap in the new signal mask, and wait for a signal.
246  */
247 
248 #ifdef CONFIG_TRAD_SIGNALS
249 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
250 {
251 	sigset_t newset;
252 	sigset_t __user *uset;
253 
254 	uset = (sigset_t __user *) regs.regs[4];
255 	if (copy_from_user(&newset, uset, sizeof(sigset_t)))
256 		return -EFAULT;
257 	sigdelsetmask(&newset, ~_BLOCKABLE);
258 
259 	spin_lock_irq(&current->sighand->siglock);
260 	current->saved_sigmask = current->blocked;
261 	current->blocked = newset;
262 	recalc_sigpending();
263 	spin_unlock_irq(&current->sighand->siglock);
264 
265 	current->state = TASK_INTERRUPTIBLE;
266 	schedule();
267 	set_thread_flag(TIF_RESTORE_SIGMASK);
268 	return -ERESTARTNOHAND;
269 }
270 #endif
271 
272 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
273 {
274 	sigset_t newset;
275 	sigset_t __user *unewset;
276 	size_t sigsetsize;
277 
278 	/* XXX Don't preclude handling different sized sigset_t's.  */
279 	sigsetsize = regs.regs[5];
280 	if (sigsetsize != sizeof(sigset_t))
281 		return -EINVAL;
282 
283 	unewset = (sigset_t __user *) regs.regs[4];
284 	if (copy_from_user(&newset, unewset, sizeof(newset)))
285 		return -EFAULT;
286 	sigdelsetmask(&newset, ~_BLOCKABLE);
287 
288 	spin_lock_irq(&current->sighand->siglock);
289 	current->saved_sigmask = current->blocked;
290 	current->blocked = newset;
291 	recalc_sigpending();
292 	spin_unlock_irq(&current->sighand->siglock);
293 
294 	current->state = TASK_INTERRUPTIBLE;
295 	schedule();
296 	set_thread_flag(TIF_RESTORE_SIGMASK);
297 	return -ERESTARTNOHAND;
298 }
299 
300 #ifdef CONFIG_TRAD_SIGNALS
301 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
302 	struct sigaction __user *, oact)
303 {
304 	struct k_sigaction new_ka, old_ka;
305 	int ret;
306 	int err = 0;
307 
308 	if (act) {
309 		old_sigset_t mask;
310 
311 		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
312 			return -EFAULT;
313 		err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
314 		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
315 		err |= __get_user(mask, &act->sa_mask.sig[0]);
316 		if (err)
317 			return -EFAULT;
318 
319 		siginitset(&new_ka.sa.sa_mask, mask);
320 	}
321 
322 	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
323 
324 	if (!ret && oact) {
325 		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
326 			return -EFAULT;
327 		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
328 		err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
329 		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
330 		err |= __put_user(0, &oact->sa_mask.sig[1]);
331 		err |= __put_user(0, &oact->sa_mask.sig[2]);
332 		err |= __put_user(0, &oact->sa_mask.sig[3]);
333 		if (err)
334 			return -EFAULT;
335 	}
336 
337 	return ret;
338 }
339 #endif
340 
341 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
342 {
343 	const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
344 	stack_t __user *uoss = (stack_t __user *) regs.regs[5];
345 	unsigned long usp = regs.regs[29];
346 
347 	return do_sigaltstack(uss, uoss, usp);
348 }
349 
350 #ifdef CONFIG_TRAD_SIGNALS
351 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
352 {
353 	struct sigframe __user *frame;
354 	sigset_t blocked;
355 	int sig;
356 
357 	frame = (struct sigframe __user *) regs.regs[29];
358 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
359 		goto badframe;
360 	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
361 		goto badframe;
362 
363 	sigdelsetmask(&blocked, ~_BLOCKABLE);
364 	spin_lock_irq(&current->sighand->siglock);
365 	current->blocked = blocked;
366 	recalc_sigpending();
367 	spin_unlock_irq(&current->sighand->siglock);
368 
369 	sig = restore_sigcontext(&regs, &frame->sf_sc);
370 	if (sig < 0)
371 		goto badframe;
372 	else if (sig)
373 		force_sig(sig, current);
374 
375 	/*
376 	 * Don't let your children do this ...
377 	 */
378 	__asm__ __volatile__(
379 		"move\t$29, %0\n\t"
380 		"j\tsyscall_exit"
381 		:/* no outputs */
382 		:"r" (&regs));
383 	/* Unreached */
384 
385 badframe:
386 	force_sig(SIGSEGV, current);
387 }
388 #endif /* CONFIG_TRAD_SIGNALS */
389 
390 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
391 {
392 	struct rt_sigframe __user *frame;
393 	sigset_t set;
394 	int sig;
395 
396 	frame = (struct rt_sigframe __user *) regs.regs[29];
397 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
398 		goto badframe;
399 	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
400 		goto badframe;
401 
402 	sigdelsetmask(&set, ~_BLOCKABLE);
403 	spin_lock_irq(&current->sighand->siglock);
404 	current->blocked = set;
405 	recalc_sigpending();
406 	spin_unlock_irq(&current->sighand->siglock);
407 
408 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
409 	if (sig < 0)
410 		goto badframe;
411 	else if (sig)
412 		force_sig(sig, current);
413 
414 	/* It is more difficult to avoid calling this function than to
415 	   call it and ignore errors.  */
416 	do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
417 
418 	/*
419 	 * Don't let your children do this ...
420 	 */
421 	__asm__ __volatile__(
422 		"move\t$29, %0\n\t"
423 		"j\tsyscall_exit"
424 		:/* no outputs */
425 		:"r" (&regs));
426 	/* Unreached */
427 
428 badframe:
429 	force_sig(SIGSEGV, current);
430 }
431 
432 #ifdef CONFIG_TRAD_SIGNALS
433 static int setup_frame(void *sig_return, struct k_sigaction *ka,
434 		       struct pt_regs *regs, int signr, sigset_t *set)
435 {
436 	struct sigframe __user *frame;
437 	int err = 0;
438 
439 	frame = get_sigframe(ka, regs, sizeof(*frame));
440 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
441 		goto give_sigsegv;
442 
443 	err |= setup_sigcontext(regs, &frame->sf_sc);
444 	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
445 	if (err)
446 		goto give_sigsegv;
447 
448 	/*
449 	 * Arguments to signal handler:
450 	 *
451 	 *   a0 = signal number
452 	 *   a1 = 0 (should be cause)
453 	 *   a2 = pointer to struct sigcontext
454 	 *
455 	 * $25 and c0_epc point to the signal handler, $29 points to the
456 	 * struct sigframe.
457 	 */
458 	regs->regs[ 4] = signr;
459 	regs->regs[ 5] = 0;
460 	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
461 	regs->regs[29] = (unsigned long) frame;
462 	regs->regs[31] = (unsigned long) sig_return;
463 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
464 
465 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
466 	       current->comm, current->pid,
467 	       frame, regs->cp0_epc, regs->regs[31]);
468 	return 0;
469 
470 give_sigsegv:
471 	force_sigsegv(signr, current);
472 	return -EFAULT;
473 }
474 #endif
475 
476 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
477 			  struct pt_regs *regs,	int signr, sigset_t *set,
478 			  siginfo_t *info)
479 {
480 	struct rt_sigframe __user *frame;
481 	int err = 0;
482 
483 	frame = get_sigframe(ka, regs, sizeof(*frame));
484 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
485 		goto give_sigsegv;
486 
487 	/* Create siginfo.  */
488 	err |= copy_siginfo_to_user(&frame->rs_info, info);
489 
490 	/* Create the ucontext.  */
491 	err |= __put_user(0, &frame->rs_uc.uc_flags);
492 	err |= __put_user(NULL, &frame->rs_uc.uc_link);
493 	err |= __put_user((void __user *)current->sas_ss_sp,
494 	                  &frame->rs_uc.uc_stack.ss_sp);
495 	err |= __put_user(sas_ss_flags(regs->regs[29]),
496 	                  &frame->rs_uc.uc_stack.ss_flags);
497 	err |= __put_user(current->sas_ss_size,
498 	                  &frame->rs_uc.uc_stack.ss_size);
499 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
500 	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
501 
502 	if (err)
503 		goto give_sigsegv;
504 
505 	/*
506 	 * Arguments to signal handler:
507 	 *
508 	 *   a0 = signal number
509 	 *   a1 = 0 (should be cause)
510 	 *   a2 = pointer to ucontext
511 	 *
512 	 * $25 and c0_epc point to the signal handler, $29 points to
513 	 * the struct rt_sigframe.
514 	 */
515 	regs->regs[ 4] = signr;
516 	regs->regs[ 5] = (unsigned long) &frame->rs_info;
517 	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
518 	regs->regs[29] = (unsigned long) frame;
519 	regs->regs[31] = (unsigned long) sig_return;
520 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
521 
522 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
523 	       current->comm, current->pid,
524 	       frame, regs->cp0_epc, regs->regs[31]);
525 
526 	return 0;
527 
528 give_sigsegv:
529 	force_sigsegv(signr, current);
530 	return -EFAULT;
531 }
532 
533 struct mips_abi mips_abi = {
534 #ifdef CONFIG_TRAD_SIGNALS
535 	.setup_frame	= setup_frame,
536 	.signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
537 #endif
538 	.setup_rt_frame	= setup_rt_frame,
539 	.rt_signal_return_offset =
540 		offsetof(struct mips_vdso, rt_signal_trampoline),
541 	.restart	= __NR_restart_syscall
542 };
543 
544 static int handle_signal(unsigned long sig, siginfo_t *info,
545 	struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
546 {
547 	int ret;
548 	struct mips_abi *abi = current->thread.abi;
549 	void *vdso = current->mm->context.vdso;
550 
551 	if (regs->regs[0]) {
552 		switch(regs->regs[2]) {
553 		case ERESTART_RESTARTBLOCK:
554 		case ERESTARTNOHAND:
555 			regs->regs[2] = EINTR;
556 			break;
557 		case ERESTARTSYS:
558 			if (!(ka->sa.sa_flags & SA_RESTART)) {
559 				regs->regs[2] = EINTR;
560 				break;
561 			}
562 		/* fallthrough */
563 		case ERESTARTNOINTR:
564 			regs->regs[7] = regs->regs[26];
565 			regs->regs[2] = regs->regs[0];
566 			regs->cp0_epc -= 4;
567 		}
568 
569 		regs->regs[0] = 0;		/* Don't deal with this again.  */
570 	}
571 
572 	if (sig_uses_siginfo(ka))
573 		ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
574 					  ka, regs, sig, oldset, info);
575 	else
576 		ret = abi->setup_frame(vdso + abi->signal_return_offset,
577 				       ka, regs, sig, oldset);
578 
579 	if (ret)
580 		return ret;
581 
582 	spin_lock_irq(&current->sighand->siglock);
583 	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
584 	if (!(ka->sa.sa_flags & SA_NODEFER))
585 		sigaddset(&current->blocked, sig);
586 	recalc_sigpending();
587 	spin_unlock_irq(&current->sighand->siglock);
588 
589 	return ret;
590 }
591 
592 static void do_signal(struct pt_regs *regs)
593 {
594 	struct k_sigaction ka;
595 	sigset_t *oldset;
596 	siginfo_t info;
597 	int signr;
598 
599 	/*
600 	 * We want the common case to go fast, which is why we may in certain
601 	 * cases get here from kernel mode. Just return without doing anything
602 	 * if so.
603 	 */
604 	if (!user_mode(regs))
605 		return;
606 
607 	if (test_thread_flag(TIF_RESTORE_SIGMASK))
608 		oldset = &current->saved_sigmask;
609 	else
610 		oldset = &current->blocked;
611 
612 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
613 	if (signr > 0) {
614 		/* Whee!  Actually deliver the signal.  */
615 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
616 			/*
617 			 * A signal was successfully delivered; the saved
618 			 * sigmask will have been stored in the signal frame,
619 			 * and will be restored by sigreturn, so we can simply
620 			 * clear the TIF_RESTORE_SIGMASK flag.
621 			 */
622 			if (test_thread_flag(TIF_RESTORE_SIGMASK))
623 				clear_thread_flag(TIF_RESTORE_SIGMASK);
624 		}
625 
626 		return;
627 	}
628 
629 	if (regs->regs[0]) {
630 		if (regs->regs[2] == ERESTARTNOHAND ||
631 		    regs->regs[2] == ERESTARTSYS ||
632 		    regs->regs[2] == ERESTARTNOINTR) {
633 			regs->regs[2] = regs->regs[0];
634 			regs->regs[7] = regs->regs[26];
635 			regs->cp0_epc -= 4;
636 		}
637 		if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
638 			regs->regs[2] = current->thread.abi->restart;
639 			regs->regs[7] = regs->regs[26];
640 			regs->cp0_epc -= 4;
641 		}
642 		regs->regs[0] = 0;	/* Don't deal with this again.  */
643 	}
644 
645 	/*
646 	 * If there's no signal to deliver, we just put the saved sigmask
647 	 * back
648 	 */
649 	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
650 		clear_thread_flag(TIF_RESTORE_SIGMASK);
651 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
652 	}
653 }
654 
655 /*
656  * notification of userspace execution resumption
657  * - triggered by the TIF_WORK_MASK flags
658  */
659 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
660 	__u32 thread_info_flags)
661 {
662 	local_irq_enable();
663 
664 	/* deal with pending signal delivery */
665 	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
666 		do_signal(regs);
667 
668 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
669 		clear_thread_flag(TIF_NOTIFY_RESUME);
670 		tracehook_notify_resume(regs);
671 		if (current->replacement_session_keyring)
672 			key_replace_session_keyring();
673 	}
674 }
675 
676 #ifdef CONFIG_SMP
677 static int smp_save_fp_context(struct sigcontext __user *sc)
678 {
679 	return raw_cpu_has_fpu
680 	       ? _save_fp_context(sc)
681 	       : fpu_emulator_save_context(sc);
682 }
683 
684 static int smp_restore_fp_context(struct sigcontext __user *sc)
685 {
686 	return raw_cpu_has_fpu
687 	       ? _restore_fp_context(sc)
688 	       : fpu_emulator_restore_context(sc);
689 }
690 #endif
691 
692 static int signal_setup(void)
693 {
694 #ifdef CONFIG_SMP
695 	/* For now just do the cpu_has_fpu check when the functions are invoked */
696 	save_fp_context = smp_save_fp_context;
697 	restore_fp_context = smp_restore_fp_context;
698 #else
699 	if (cpu_has_fpu) {
700 		save_fp_context = _save_fp_context;
701 		restore_fp_context = _restore_fp_context;
702 	} else {
703 		save_fp_context = fpu_emulator_save_context;
704 		restore_fp_context = fpu_emulator_restore_context;
705 	}
706 #endif
707 
708 	return 0;
709 }
710 
711 arch_initcall(signal_setup);
712