xref: /openbmc/linux/arch/mips/kernel/signal.c (revision 8ac727c1)
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/syscalls.h>
23 #include <linux/uaccess.h>
24 #include <linux/tracehook.h>
25 
26 #include <asm/abi.h>
27 #include <asm/asm.h>
28 #include <linux/bitops.h>
29 #include <asm/cacheflush.h>
30 #include <asm/fpu.h>
31 #include <asm/sim.h>
32 #include <asm/ucontext.h>
33 #include <asm/cpu-features.h>
34 #include <asm/war.h>
35 #include <asm/vdso.h>
36 
37 #include "signal-common.h"
38 
39 static int (*save_fp_context)(struct sigcontext __user *sc);
40 static int (*restore_fp_context)(struct sigcontext __user *sc);
41 
42 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
43 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
44 
45 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
46 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
47 
48 struct sigframe {
49 	u32 sf_ass[4];		/* argument save space for o32 */
50 	u32 sf_pad[2];		/* Was: signal trampoline */
51 	struct sigcontext sf_sc;
52 	sigset_t sf_mask;
53 };
54 
55 struct rt_sigframe {
56 	u32 rs_ass[4];		/* argument save space for o32 */
57 	u32 rs_pad[2];		/* Was: signal trampoline */
58 	struct siginfo rs_info;
59 	struct ucontext rs_uc;
60 };
61 
62 /*
63  * Helper routines
64  */
65 static int protected_save_fp_context(struct sigcontext __user *sc)
66 {
67 	int err;
68 	while (1) {
69 		lock_fpu_owner();
70 		own_fpu_inatomic(1);
71 		err = save_fp_context(sc); /* this might fail */
72 		unlock_fpu_owner();
73 		if (likely(!err))
74 			break;
75 		/* touch the sigcontext and try again */
76 		err = __put_user(0, &sc->sc_fpregs[0]) |
77 			__put_user(0, &sc->sc_fpregs[31]) |
78 			__put_user(0, &sc->sc_fpc_csr);
79 		if (err)
80 			break;	/* really bad sigcontext */
81 	}
82 	return err;
83 }
84 
85 static int protected_restore_fp_context(struct sigcontext __user *sc)
86 {
87 	int err, tmp __maybe_unused;
88 	while (1) {
89 		lock_fpu_owner();
90 		own_fpu_inatomic(0);
91 		err = restore_fp_context(sc); /* this might fail */
92 		unlock_fpu_owner();
93 		if (likely(!err))
94 			break;
95 		/* touch the sigcontext and try again */
96 		err = __get_user(tmp, &sc->sc_fpregs[0]) |
97 			__get_user(tmp, &sc->sc_fpregs[31]) |
98 			__get_user(tmp, &sc->sc_fpc_csr);
99 		if (err)
100 			break;	/* really bad sigcontext */
101 	}
102 	return err;
103 }
104 
105 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
106 {
107 	int err = 0;
108 	int i;
109 	unsigned int used_math;
110 
111 	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
112 
113 	err |= __put_user(0, &sc->sc_regs[0]);
114 	for (i = 1; i < 32; i++)
115 		err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
116 
117 #ifdef CONFIG_CPU_HAS_SMARTMIPS
118 	err |= __put_user(regs->acx, &sc->sc_acx);
119 #endif
120 	err |= __put_user(regs->hi, &sc->sc_mdhi);
121 	err |= __put_user(regs->lo, &sc->sc_mdlo);
122 	if (cpu_has_dsp) {
123 		err |= __put_user(mfhi1(), &sc->sc_hi1);
124 		err |= __put_user(mflo1(), &sc->sc_lo1);
125 		err |= __put_user(mfhi2(), &sc->sc_hi2);
126 		err |= __put_user(mflo2(), &sc->sc_lo2);
127 		err |= __put_user(mfhi3(), &sc->sc_hi3);
128 		err |= __put_user(mflo3(), &sc->sc_lo3);
129 		err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
130 	}
131 
132 	used_math = !!used_math();
133 	err |= __put_user(used_math, &sc->sc_used_math);
134 
135 	if (used_math) {
136 		/*
137 		 * Save FPU state to signal context. Signal handler
138 		 * will "inherit" current FPU state.
139 		 */
140 		err |= protected_save_fp_context(sc);
141 	}
142 	return err;
143 }
144 
145 int fpcsr_pending(unsigned int __user *fpcsr)
146 {
147 	int err, sig = 0;
148 	unsigned int csr, enabled;
149 
150 	err = __get_user(csr, fpcsr);
151 	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
152 	/*
153 	 * If the signal handler set some FPU exceptions, clear it and
154 	 * send SIGFPE.
155 	 */
156 	if (csr & enabled) {
157 		csr &= ~enabled;
158 		err |= __put_user(csr, fpcsr);
159 		sig = SIGFPE;
160 	}
161 	return err ?: sig;
162 }
163 
164 static int
165 check_and_restore_fp_context(struct sigcontext __user *sc)
166 {
167 	int err, sig;
168 
169 	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
170 	if (err > 0)
171 		err = 0;
172 	err |= protected_restore_fp_context(sc);
173 	return err ?: sig;
174 }
175 
176 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
177 {
178 	unsigned int used_math;
179 	unsigned long treg;
180 	int err = 0;
181 	int i;
182 
183 	/* Always make any pending restarted system calls return -EINTR */
184 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
185 
186 	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
187 
188 #ifdef CONFIG_CPU_HAS_SMARTMIPS
189 	err |= __get_user(regs->acx, &sc->sc_acx);
190 #endif
191 	err |= __get_user(regs->hi, &sc->sc_mdhi);
192 	err |= __get_user(regs->lo, &sc->sc_mdlo);
193 	if (cpu_has_dsp) {
194 		err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
195 		err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
196 		err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
197 		err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
198 		err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
199 		err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
200 		err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
201 	}
202 
203 	for (i = 1; i < 32; i++)
204 		err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
205 
206 	err |= __get_user(used_math, &sc->sc_used_math);
207 	conditional_used_math(used_math);
208 
209 	if (used_math) {
210 		/* restore fpu context if we have used it before */
211 		if (!err)
212 			err = check_and_restore_fp_context(sc);
213 	} else {
214 		/* signal handler may have used FPU.  Give it up. */
215 		lose_fpu(0);
216 	}
217 
218 	return err;
219 }
220 
221 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
222 			  size_t frame_size)
223 {
224 	unsigned long sp;
225 
226 	/* Default to using normal stack */
227 	sp = regs->regs[29];
228 
229 	/*
230 	 * FPU emulator may have it's own trampoline active just
231 	 * above the user stack, 16-bytes before the next lowest
232 	 * 16 byte boundary.  Try to avoid trashing it.
233 	 */
234 	sp -= 32;
235 
236 	/* This is the X/Open sanctioned signal stack switching.  */
237 	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
238 		sp = current->sas_ss_sp + current->sas_ss_size;
239 
240 	return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
241 }
242 
243 /*
244  * Atomically swap in the new signal mask, and wait for a signal.
245  */
246 
247 #ifdef CONFIG_TRAD_SIGNALS
248 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
249 {
250 	sigset_t newset;
251 	sigset_t __user *uset;
252 
253 	uset = (sigset_t __user *) regs.regs[4];
254 	if (copy_from_user(&newset, uset, sizeof(sigset_t)))
255 		return -EFAULT;
256 	sigdelsetmask(&newset, ~_BLOCKABLE);
257 
258 	spin_lock_irq(&current->sighand->siglock);
259 	current->saved_sigmask = current->blocked;
260 	current->blocked = newset;
261 	recalc_sigpending();
262 	spin_unlock_irq(&current->sighand->siglock);
263 
264 	current->state = TASK_INTERRUPTIBLE;
265 	schedule();
266 	set_thread_flag(TIF_RESTORE_SIGMASK);
267 	return -ERESTARTNOHAND;
268 }
269 #endif
270 
271 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
272 {
273 	sigset_t newset;
274 	sigset_t __user *unewset;
275 	size_t sigsetsize;
276 
277 	/* XXX Don't preclude handling different sized sigset_t's.  */
278 	sigsetsize = regs.regs[5];
279 	if (sigsetsize != sizeof(sigset_t))
280 		return -EINVAL;
281 
282 	unewset = (sigset_t __user *) regs.regs[4];
283 	if (copy_from_user(&newset, unewset, sizeof(newset)))
284 		return -EFAULT;
285 	sigdelsetmask(&newset, ~_BLOCKABLE);
286 
287 	spin_lock_irq(&current->sighand->siglock);
288 	current->saved_sigmask = current->blocked;
289 	current->blocked = newset;
290 	recalc_sigpending();
291 	spin_unlock_irq(&current->sighand->siglock);
292 
293 	current->state = TASK_INTERRUPTIBLE;
294 	schedule();
295 	set_thread_flag(TIF_RESTORE_SIGMASK);
296 	return -ERESTARTNOHAND;
297 }
298 
299 #ifdef CONFIG_TRAD_SIGNALS
300 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
301 	struct sigaction __user *, oact)
302 {
303 	struct k_sigaction new_ka, old_ka;
304 	int ret;
305 	int err = 0;
306 
307 	if (act) {
308 		old_sigset_t mask;
309 
310 		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
311 			return -EFAULT;
312 		err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
313 		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
314 		err |= __get_user(mask, &act->sa_mask.sig[0]);
315 		if (err)
316 			return -EFAULT;
317 
318 		siginitset(&new_ka.sa.sa_mask, mask);
319 	}
320 
321 	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
322 
323 	if (!ret && oact) {
324 		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
325 			return -EFAULT;
326 		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
327 		err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
328 		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
329 		err |= __put_user(0, &oact->sa_mask.sig[1]);
330 		err |= __put_user(0, &oact->sa_mask.sig[2]);
331 		err |= __put_user(0, &oact->sa_mask.sig[3]);
332 		if (err)
333 			return -EFAULT;
334 	}
335 
336 	return ret;
337 }
338 #endif
339 
340 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
341 {
342 	const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
343 	stack_t __user *uoss = (stack_t __user *) regs.regs[5];
344 	unsigned long usp = regs.regs[29];
345 
346 	return do_sigaltstack(uss, uoss, usp);
347 }
348 
349 #ifdef CONFIG_TRAD_SIGNALS
350 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
351 {
352 	struct sigframe __user *frame;
353 	sigset_t blocked;
354 	int sig;
355 
356 	frame = (struct sigframe __user *) regs.regs[29];
357 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
358 		goto badframe;
359 	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
360 		goto badframe;
361 
362 	sigdelsetmask(&blocked, ~_BLOCKABLE);
363 	spin_lock_irq(&current->sighand->siglock);
364 	current->blocked = blocked;
365 	recalc_sigpending();
366 	spin_unlock_irq(&current->sighand->siglock);
367 
368 	sig = restore_sigcontext(&regs, &frame->sf_sc);
369 	if (sig < 0)
370 		goto badframe;
371 	else if (sig)
372 		force_sig(sig, current);
373 
374 	/*
375 	 * Don't let your children do this ...
376 	 */
377 	__asm__ __volatile__(
378 		"move\t$29, %0\n\t"
379 		"j\tsyscall_exit"
380 		:/* no outputs */
381 		:"r" (&regs));
382 	/* Unreached */
383 
384 badframe:
385 	force_sig(SIGSEGV, current);
386 }
387 #endif /* CONFIG_TRAD_SIGNALS */
388 
389 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
390 {
391 	struct rt_sigframe __user *frame;
392 	sigset_t set;
393 	int sig;
394 
395 	frame = (struct rt_sigframe __user *) regs.regs[29];
396 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
397 		goto badframe;
398 	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
399 		goto badframe;
400 
401 	sigdelsetmask(&set, ~_BLOCKABLE);
402 	spin_lock_irq(&current->sighand->siglock);
403 	current->blocked = set;
404 	recalc_sigpending();
405 	spin_unlock_irq(&current->sighand->siglock);
406 
407 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
408 	if (sig < 0)
409 		goto badframe;
410 	else if (sig)
411 		force_sig(sig, current);
412 
413 	/* It is more difficult to avoid calling this function than to
414 	   call it and ignore errors.  */
415 	do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
416 
417 	/*
418 	 * Don't let your children do this ...
419 	 */
420 	__asm__ __volatile__(
421 		"move\t$29, %0\n\t"
422 		"j\tsyscall_exit"
423 		:/* no outputs */
424 		:"r" (&regs));
425 	/* Unreached */
426 
427 badframe:
428 	force_sig(SIGSEGV, current);
429 }
430 
431 #ifdef CONFIG_TRAD_SIGNALS
432 static int setup_frame(void *sig_return, struct k_sigaction *ka,
433 		       struct pt_regs *regs, int signr, sigset_t *set)
434 {
435 	struct sigframe __user *frame;
436 	int err = 0;
437 
438 	frame = get_sigframe(ka, regs, sizeof(*frame));
439 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
440 		goto give_sigsegv;
441 
442 	err |= setup_sigcontext(regs, &frame->sf_sc);
443 	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
444 	if (err)
445 		goto give_sigsegv;
446 
447 	/*
448 	 * Arguments to signal handler:
449 	 *
450 	 *   a0 = signal number
451 	 *   a1 = 0 (should be cause)
452 	 *   a2 = pointer to struct sigcontext
453 	 *
454 	 * $25 and c0_epc point to the signal handler, $29 points to the
455 	 * struct sigframe.
456 	 */
457 	regs->regs[ 4] = signr;
458 	regs->regs[ 5] = 0;
459 	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
460 	regs->regs[29] = (unsigned long) frame;
461 	regs->regs[31] = (unsigned long) sig_return;
462 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
463 
464 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
465 	       current->comm, current->pid,
466 	       frame, regs->cp0_epc, regs->regs[31]);
467 	return 0;
468 
469 give_sigsegv:
470 	force_sigsegv(signr, current);
471 	return -EFAULT;
472 }
473 #endif
474 
475 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
476 			  struct pt_regs *regs,	int signr, sigset_t *set,
477 			  siginfo_t *info)
478 {
479 	struct rt_sigframe __user *frame;
480 	int err = 0;
481 
482 	frame = get_sigframe(ka, regs, sizeof(*frame));
483 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
484 		goto give_sigsegv;
485 
486 	/* Create siginfo.  */
487 	err |= copy_siginfo_to_user(&frame->rs_info, info);
488 
489 	/* Create the ucontext.  */
490 	err |= __put_user(0, &frame->rs_uc.uc_flags);
491 	err |= __put_user(NULL, &frame->rs_uc.uc_link);
492 	err |= __put_user((void __user *)current->sas_ss_sp,
493 	                  &frame->rs_uc.uc_stack.ss_sp);
494 	err |= __put_user(sas_ss_flags(regs->regs[29]),
495 	                  &frame->rs_uc.uc_stack.ss_flags);
496 	err |= __put_user(current->sas_ss_size,
497 	                  &frame->rs_uc.uc_stack.ss_size);
498 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
499 	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
500 
501 	if (err)
502 		goto give_sigsegv;
503 
504 	/*
505 	 * Arguments to signal handler:
506 	 *
507 	 *   a0 = signal number
508 	 *   a1 = 0 (should be cause)
509 	 *   a2 = pointer to ucontext
510 	 *
511 	 * $25 and c0_epc point to the signal handler, $29 points to
512 	 * the struct rt_sigframe.
513 	 */
514 	regs->regs[ 4] = signr;
515 	regs->regs[ 5] = (unsigned long) &frame->rs_info;
516 	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
517 	regs->regs[29] = (unsigned long) frame;
518 	regs->regs[31] = (unsigned long) sig_return;
519 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
520 
521 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
522 	       current->comm, current->pid,
523 	       frame, regs->cp0_epc, regs->regs[31]);
524 
525 	return 0;
526 
527 give_sigsegv:
528 	force_sigsegv(signr, current);
529 	return -EFAULT;
530 }
531 
532 struct mips_abi mips_abi = {
533 #ifdef CONFIG_TRAD_SIGNALS
534 	.setup_frame	= setup_frame,
535 	.signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
536 #endif
537 	.setup_rt_frame	= setup_rt_frame,
538 	.rt_signal_return_offset =
539 		offsetof(struct mips_vdso, rt_signal_trampoline),
540 	.restart	= __NR_restart_syscall
541 };
542 
543 static int handle_signal(unsigned long sig, siginfo_t *info,
544 	struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
545 {
546 	int ret;
547 	struct mips_abi *abi = current->thread.abi;
548 	void *vdso = current->mm->context.vdso;
549 
550 	if (regs->regs[0]) {
551 		switch(regs->regs[2]) {
552 		case ERESTART_RESTARTBLOCK:
553 		case ERESTARTNOHAND:
554 			regs->regs[2] = EINTR;
555 			break;
556 		case ERESTARTSYS:
557 			if (!(ka->sa.sa_flags & SA_RESTART)) {
558 				regs->regs[2] = EINTR;
559 				break;
560 			}
561 		/* fallthrough */
562 		case ERESTARTNOINTR:
563 			regs->regs[7] = regs->regs[26];
564 			regs->regs[2] = regs->regs[0];
565 			regs->cp0_epc -= 4;
566 		}
567 
568 		regs->regs[0] = 0;		/* Don't deal with this again.  */
569 	}
570 
571 	if (sig_uses_siginfo(ka))
572 		ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
573 					  ka, regs, sig, oldset, info);
574 	else
575 		ret = abi->setup_frame(vdso + abi->signal_return_offset,
576 				       ka, regs, sig, oldset);
577 
578 	if (ret)
579 		return ret;
580 
581 	spin_lock_irq(&current->sighand->siglock);
582 	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
583 	if (!(ka->sa.sa_flags & SA_NODEFER))
584 		sigaddset(&current->blocked, sig);
585 	recalc_sigpending();
586 	spin_unlock_irq(&current->sighand->siglock);
587 
588 	return ret;
589 }
590 
591 static void do_signal(struct pt_regs *regs)
592 {
593 	struct k_sigaction ka;
594 	sigset_t *oldset;
595 	siginfo_t info;
596 	int signr;
597 
598 	/*
599 	 * We want the common case to go fast, which is why we may in certain
600 	 * cases get here from kernel mode. Just return without doing anything
601 	 * if so.
602 	 */
603 	if (!user_mode(regs))
604 		return;
605 
606 	if (test_thread_flag(TIF_RESTORE_SIGMASK))
607 		oldset = &current->saved_sigmask;
608 	else
609 		oldset = &current->blocked;
610 
611 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
612 	if (signr > 0) {
613 		/* Whee!  Actually deliver the signal.  */
614 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
615 			/*
616 			 * A signal was successfully delivered; the saved
617 			 * sigmask will have been stored in the signal frame,
618 			 * and will be restored by sigreturn, so we can simply
619 			 * clear the TIF_RESTORE_SIGMASK flag.
620 			 */
621 			if (test_thread_flag(TIF_RESTORE_SIGMASK))
622 				clear_thread_flag(TIF_RESTORE_SIGMASK);
623 		}
624 
625 		return;
626 	}
627 
628 	if (regs->regs[0]) {
629 		if (regs->regs[2] == ERESTARTNOHAND ||
630 		    regs->regs[2] == ERESTARTSYS ||
631 		    regs->regs[2] == ERESTARTNOINTR) {
632 			regs->regs[2] = regs->regs[0];
633 			regs->regs[7] = regs->regs[26];
634 			regs->cp0_epc -= 4;
635 		}
636 		if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
637 			regs->regs[2] = current->thread.abi->restart;
638 			regs->regs[7] = regs->regs[26];
639 			regs->cp0_epc -= 4;
640 		}
641 		regs->regs[0] = 0;	/* Don't deal with this again.  */
642 	}
643 
644 	/*
645 	 * If there's no signal to deliver, we just put the saved sigmask
646 	 * back
647 	 */
648 	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
649 		clear_thread_flag(TIF_RESTORE_SIGMASK);
650 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
651 	}
652 }
653 
654 /*
655  * notification of userspace execution resumption
656  * - triggered by the TIF_WORK_MASK flags
657  */
658 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
659 	__u32 thread_info_flags)
660 {
661 	/* deal with pending signal delivery */
662 	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
663 		do_signal(regs);
664 
665 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
666 		clear_thread_flag(TIF_NOTIFY_RESUME);
667 		tracehook_notify_resume(regs);
668 		if (current->replacement_session_keyring)
669 			key_replace_session_keyring();
670 	}
671 }
672 
673 #ifdef CONFIG_SMP
674 static int smp_save_fp_context(struct sigcontext __user *sc)
675 {
676 	return raw_cpu_has_fpu
677 	       ? _save_fp_context(sc)
678 	       : fpu_emulator_save_context(sc);
679 }
680 
681 static int smp_restore_fp_context(struct sigcontext __user *sc)
682 {
683 	return raw_cpu_has_fpu
684 	       ? _restore_fp_context(sc)
685 	       : fpu_emulator_restore_context(sc);
686 }
687 #endif
688 
689 static int signal_setup(void)
690 {
691 #ifdef CONFIG_SMP
692 	/* For now just do the cpu_has_fpu check when the functions are invoked */
693 	save_fp_context = smp_save_fp_context;
694 	restore_fp_context = smp_restore_fp_context;
695 #else
696 	if (cpu_has_fpu) {
697 		save_fp_context = _save_fp_context;
698 		restore_fp_context = _restore_fp_context;
699 	} else {
700 		save_fp_context = fpu_emulator_save_context;
701 		restore_fp_context = fpu_emulator_restore_context;
702 	}
703 #endif
704 
705 	return 0;
706 }
707 
708 arch_initcall(signal_setup);
709