xref: /linux/arch/mips/kernel/signal.c (revision 2dbf708448c836754d25fe6108c5bfe1f5697c95)
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 #include <asm/dsp.h>
38 
39 #include "signal-common.h"
40 
41 static int (*save_fp_context)(struct sigcontext __user *sc);
42 static int (*restore_fp_context)(struct sigcontext __user *sc);
43 
44 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
45 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
46 
47 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
48 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
49 
50 struct sigframe {
51 	u32 sf_ass[4];		/* argument save space for o32 */
52 	u32 sf_pad[2];		/* Was: signal trampoline */
53 	struct sigcontext sf_sc;
54 	sigset_t sf_mask;
55 };
56 
57 struct rt_sigframe {
58 	u32 rs_ass[4];		/* argument save space for o32 */
59 	u32 rs_pad[2];		/* Was: signal trampoline */
60 	struct siginfo rs_info;
61 	struct ucontext rs_uc;
62 };
63 
64 /*
65  * Helper routines
66  */
67 static int protected_save_fp_context(struct sigcontext __user *sc)
68 {
69 	int err;
70 	while (1) {
71 		lock_fpu_owner();
72 		own_fpu_inatomic(1);
73 		err = save_fp_context(sc); /* this might fail */
74 		unlock_fpu_owner();
75 		if (likely(!err))
76 			break;
77 		/* touch the sigcontext and try again */
78 		err = __put_user(0, &sc->sc_fpregs[0]) |
79 			__put_user(0, &sc->sc_fpregs[31]) |
80 			__put_user(0, &sc->sc_fpc_csr);
81 		if (err)
82 			break;	/* really bad sigcontext */
83 	}
84 	return err;
85 }
86 
87 static int protected_restore_fp_context(struct sigcontext __user *sc)
88 {
89 	int err, tmp __maybe_unused;
90 	while (1) {
91 		lock_fpu_owner();
92 		own_fpu_inatomic(0);
93 		err = restore_fp_context(sc); /* this might fail */
94 		unlock_fpu_owner();
95 		if (likely(!err))
96 			break;
97 		/* touch the sigcontext and try again */
98 		err = __get_user(tmp, &sc->sc_fpregs[0]) |
99 			__get_user(tmp, &sc->sc_fpregs[31]) |
100 			__get_user(tmp, &sc->sc_fpc_csr);
101 		if (err)
102 			break;	/* really bad sigcontext */
103 	}
104 	return err;
105 }
106 
107 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
108 {
109 	int err = 0;
110 	int i;
111 	unsigned int used_math;
112 
113 	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
114 
115 	err |= __put_user(0, &sc->sc_regs[0]);
116 	for (i = 1; i < 32; i++)
117 		err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
118 
119 #ifdef CONFIG_CPU_HAS_SMARTMIPS
120 	err |= __put_user(regs->acx, &sc->sc_acx);
121 #endif
122 	err |= __put_user(regs->hi, &sc->sc_mdhi);
123 	err |= __put_user(regs->lo, &sc->sc_mdlo);
124 	if (cpu_has_dsp) {
125 		err |= __put_user(mfhi1(), &sc->sc_hi1);
126 		err |= __put_user(mflo1(), &sc->sc_lo1);
127 		err |= __put_user(mfhi2(), &sc->sc_hi2);
128 		err |= __put_user(mflo2(), &sc->sc_lo2);
129 		err |= __put_user(mfhi3(), &sc->sc_hi3);
130 		err |= __put_user(mflo3(), &sc->sc_lo3);
131 		err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
132 	}
133 
134 	used_math = !!used_math();
135 	err |= __put_user(used_math, &sc->sc_used_math);
136 
137 	if (used_math) {
138 		/*
139 		 * Save FPU state to signal context. Signal handler
140 		 * will "inherit" current FPU state.
141 		 */
142 		err |= protected_save_fp_context(sc);
143 	}
144 	return err;
145 }
146 
147 int fpcsr_pending(unsigned int __user *fpcsr)
148 {
149 	int err, sig = 0;
150 	unsigned int csr, enabled;
151 
152 	err = __get_user(csr, fpcsr);
153 	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
154 	/*
155 	 * If the signal handler set some FPU exceptions, clear it and
156 	 * send SIGFPE.
157 	 */
158 	if (csr & enabled) {
159 		csr &= ~enabled;
160 		err |= __put_user(csr, fpcsr);
161 		sig = SIGFPE;
162 	}
163 	return err ?: sig;
164 }
165 
166 static int
167 check_and_restore_fp_context(struct sigcontext __user *sc)
168 {
169 	int err, sig;
170 
171 	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
172 	if (err > 0)
173 		err = 0;
174 	err |= protected_restore_fp_context(sc);
175 	return err ?: sig;
176 }
177 
178 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
179 {
180 	unsigned int used_math;
181 	unsigned long treg;
182 	int err = 0;
183 	int i;
184 
185 	/* Always make any pending restarted system calls return -EINTR */
186 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
187 
188 	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
189 
190 #ifdef CONFIG_CPU_HAS_SMARTMIPS
191 	err |= __get_user(regs->acx, &sc->sc_acx);
192 #endif
193 	err |= __get_user(regs->hi, &sc->sc_mdhi);
194 	err |= __get_user(regs->lo, &sc->sc_mdlo);
195 	if (cpu_has_dsp) {
196 		err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
197 		err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
198 		err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
199 		err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
200 		err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
201 		err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
202 		err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
203 	}
204 
205 	for (i = 1; i < 32; i++)
206 		err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
207 
208 	err |= __get_user(used_math, &sc->sc_used_math);
209 	conditional_used_math(used_math);
210 
211 	if (used_math) {
212 		/* restore fpu context if we have used it before */
213 		if (!err)
214 			err = check_and_restore_fp_context(sc);
215 	} else {
216 		/* signal handler may have used FPU.  Give it up. */
217 		lose_fpu(0);
218 	}
219 
220 	return err;
221 }
222 
223 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
224 			  size_t frame_size)
225 {
226 	unsigned long sp;
227 
228 	/* Default to using normal stack */
229 	sp = regs->regs[29];
230 
231 	/*
232 	 * FPU emulator may have it's own trampoline active just
233 	 * above the user stack, 16-bytes before the next lowest
234 	 * 16 byte boundary.  Try to avoid trashing it.
235 	 */
236 	sp -= 32;
237 
238 	/* This is the X/Open sanctioned signal stack switching.  */
239 	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
240 		sp = current->sas_ss_sp + current->sas_ss_size;
241 
242 	return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
243 }
244 
245 /*
246  * Atomically swap in the new signal mask, and wait for a signal.
247  */
248 
249 #ifdef CONFIG_TRAD_SIGNALS
250 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
251 {
252 	sigset_t newset;
253 	sigset_t __user *uset;
254 
255 	uset = (sigset_t __user *) regs.regs[4];
256 	if (copy_from_user(&newset, uset, sizeof(sigset_t)))
257 		return -EFAULT;
258 	sigdelsetmask(&newset, ~_BLOCKABLE);
259 
260 	spin_lock_irq(&current->sighand->siglock);
261 	current->saved_sigmask = current->blocked;
262 	current->blocked = newset;
263 	recalc_sigpending();
264 	spin_unlock_irq(&current->sighand->siglock);
265 
266 	current->state = TASK_INTERRUPTIBLE;
267 	schedule();
268 	set_thread_flag(TIF_RESTORE_SIGMASK);
269 	return -ERESTARTNOHAND;
270 }
271 #endif
272 
273 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
274 {
275 	sigset_t newset;
276 	sigset_t __user *unewset;
277 	size_t sigsetsize;
278 
279 	/* XXX Don't preclude handling different sized sigset_t's.  */
280 	sigsetsize = regs.regs[5];
281 	if (sigsetsize != sizeof(sigset_t))
282 		return -EINVAL;
283 
284 	unewset = (sigset_t __user *) regs.regs[4];
285 	if (copy_from_user(&newset, unewset, sizeof(newset)))
286 		return -EFAULT;
287 	sigdelsetmask(&newset, ~_BLOCKABLE);
288 
289 	spin_lock_irq(&current->sighand->siglock);
290 	current->saved_sigmask = current->blocked;
291 	current->blocked = newset;
292 	recalc_sigpending();
293 	spin_unlock_irq(&current->sighand->siglock);
294 
295 	current->state = TASK_INTERRUPTIBLE;
296 	schedule();
297 	set_thread_flag(TIF_RESTORE_SIGMASK);
298 	return -ERESTARTNOHAND;
299 }
300 
301 #ifdef CONFIG_TRAD_SIGNALS
302 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
303 	struct sigaction __user *, oact)
304 {
305 	struct k_sigaction new_ka, old_ka;
306 	int ret;
307 	int err = 0;
308 
309 	if (act) {
310 		old_sigset_t mask;
311 
312 		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
313 			return -EFAULT;
314 		err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
315 		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
316 		err |= __get_user(mask, &act->sa_mask.sig[0]);
317 		if (err)
318 			return -EFAULT;
319 
320 		siginitset(&new_ka.sa.sa_mask, mask);
321 	}
322 
323 	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
324 
325 	if (!ret && oact) {
326 		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
327 			return -EFAULT;
328 		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
329 		err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
330 		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
331 		err |= __put_user(0, &oact->sa_mask.sig[1]);
332 		err |= __put_user(0, &oact->sa_mask.sig[2]);
333 		err |= __put_user(0, &oact->sa_mask.sig[3]);
334 		if (err)
335 			return -EFAULT;
336 	}
337 
338 	return ret;
339 }
340 #endif
341 
342 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
343 {
344 	const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
345 	stack_t __user *uoss = (stack_t __user *) regs.regs[5];
346 	unsigned long usp = regs.regs[29];
347 
348 	return do_sigaltstack(uss, uoss, usp);
349 }
350 
351 #ifdef CONFIG_TRAD_SIGNALS
352 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
353 {
354 	struct sigframe __user *frame;
355 	sigset_t blocked;
356 	int sig;
357 
358 	frame = (struct sigframe __user *) regs.regs[29];
359 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
360 		goto badframe;
361 	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
362 		goto badframe;
363 
364 	sigdelsetmask(&blocked, ~_BLOCKABLE);
365 	spin_lock_irq(&current->sighand->siglock);
366 	current->blocked = blocked;
367 	recalc_sigpending();
368 	spin_unlock_irq(&current->sighand->siglock);
369 
370 	sig = restore_sigcontext(&regs, &frame->sf_sc);
371 	if (sig < 0)
372 		goto badframe;
373 	else if (sig)
374 		force_sig(sig, current);
375 
376 	/*
377 	 * Don't let your children do this ...
378 	 */
379 	__asm__ __volatile__(
380 		"move\t$29, %0\n\t"
381 		"j\tsyscall_exit"
382 		:/* no outputs */
383 		:"r" (&regs));
384 	/* Unreached */
385 
386 badframe:
387 	force_sig(SIGSEGV, current);
388 }
389 #endif /* CONFIG_TRAD_SIGNALS */
390 
391 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
392 {
393 	struct rt_sigframe __user *frame;
394 	sigset_t set;
395 	int sig;
396 
397 	frame = (struct rt_sigframe __user *) regs.regs[29];
398 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
399 		goto badframe;
400 	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
401 		goto badframe;
402 
403 	sigdelsetmask(&set, ~_BLOCKABLE);
404 	spin_lock_irq(&current->sighand->siglock);
405 	current->blocked = set;
406 	recalc_sigpending();
407 	spin_unlock_irq(&current->sighand->siglock);
408 
409 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
410 	if (sig < 0)
411 		goto badframe;
412 	else if (sig)
413 		force_sig(sig, current);
414 
415 	/* It is more difficult to avoid calling this function than to
416 	   call it and ignore errors.  */
417 	do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
418 
419 	/*
420 	 * Don't let your children do this ...
421 	 */
422 	__asm__ __volatile__(
423 		"move\t$29, %0\n\t"
424 		"j\tsyscall_exit"
425 		:/* no outputs */
426 		:"r" (&regs));
427 	/* Unreached */
428 
429 badframe:
430 	force_sig(SIGSEGV, current);
431 }
432 
433 #ifdef CONFIG_TRAD_SIGNALS
434 static int setup_frame(void *sig_return, struct k_sigaction *ka,
435 		       struct pt_regs *regs, int signr, sigset_t *set)
436 {
437 	struct sigframe __user *frame;
438 	int err = 0;
439 
440 	frame = get_sigframe(ka, regs, sizeof(*frame));
441 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
442 		goto give_sigsegv;
443 
444 	err |= setup_sigcontext(regs, &frame->sf_sc);
445 	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
446 	if (err)
447 		goto give_sigsegv;
448 
449 	/*
450 	 * Arguments to signal handler:
451 	 *
452 	 *   a0 = signal number
453 	 *   a1 = 0 (should be cause)
454 	 *   a2 = pointer to struct sigcontext
455 	 *
456 	 * $25 and c0_epc point to the signal handler, $29 points to the
457 	 * struct sigframe.
458 	 */
459 	regs->regs[ 4] = signr;
460 	regs->regs[ 5] = 0;
461 	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
462 	regs->regs[29] = (unsigned long) frame;
463 	regs->regs[31] = (unsigned long) sig_return;
464 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
465 
466 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
467 	       current->comm, current->pid,
468 	       frame, regs->cp0_epc, regs->regs[31]);
469 	return 0;
470 
471 give_sigsegv:
472 	force_sigsegv(signr, current);
473 	return -EFAULT;
474 }
475 #endif
476 
477 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
478 			  struct pt_regs *regs,	int signr, sigset_t *set,
479 			  siginfo_t *info)
480 {
481 	struct rt_sigframe __user *frame;
482 	int err = 0;
483 
484 	frame = get_sigframe(ka, regs, sizeof(*frame));
485 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
486 		goto give_sigsegv;
487 
488 	/* Create siginfo.  */
489 	err |= copy_siginfo_to_user(&frame->rs_info, info);
490 
491 	/* Create the ucontext.  */
492 	err |= __put_user(0, &frame->rs_uc.uc_flags);
493 	err |= __put_user(NULL, &frame->rs_uc.uc_link);
494 	err |= __put_user((void __user *)current->sas_ss_sp,
495 	                  &frame->rs_uc.uc_stack.ss_sp);
496 	err |= __put_user(sas_ss_flags(regs->regs[29]),
497 	                  &frame->rs_uc.uc_stack.ss_flags);
498 	err |= __put_user(current->sas_ss_size,
499 	                  &frame->rs_uc.uc_stack.ss_size);
500 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
501 	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
502 
503 	if (err)
504 		goto give_sigsegv;
505 
506 	/*
507 	 * Arguments to signal handler:
508 	 *
509 	 *   a0 = signal number
510 	 *   a1 = 0 (should be cause)
511 	 *   a2 = pointer to ucontext
512 	 *
513 	 * $25 and c0_epc point to the signal handler, $29 points to
514 	 * the struct rt_sigframe.
515 	 */
516 	regs->regs[ 4] = signr;
517 	regs->regs[ 5] = (unsigned long) &frame->rs_info;
518 	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
519 	regs->regs[29] = (unsigned long) frame;
520 	regs->regs[31] = (unsigned long) sig_return;
521 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
522 
523 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
524 	       current->comm, current->pid,
525 	       frame, regs->cp0_epc, regs->regs[31]);
526 
527 	return 0;
528 
529 give_sigsegv:
530 	force_sigsegv(signr, current);
531 	return -EFAULT;
532 }
533 
534 struct mips_abi mips_abi = {
535 #ifdef CONFIG_TRAD_SIGNALS
536 	.setup_frame	= setup_frame,
537 	.signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
538 #endif
539 	.setup_rt_frame	= setup_rt_frame,
540 	.rt_signal_return_offset =
541 		offsetof(struct mips_vdso, rt_signal_trampoline),
542 	.restart	= __NR_restart_syscall
543 };
544 
545 static int handle_signal(unsigned long sig, siginfo_t *info,
546 	struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
547 {
548 	int ret;
549 	struct mips_abi *abi = current->thread.abi;
550 	void *vdso = current->mm->context.vdso;
551 
552 	if (regs->regs[0]) {
553 		switch(regs->regs[2]) {
554 		case ERESTART_RESTARTBLOCK:
555 		case ERESTARTNOHAND:
556 			regs->regs[2] = EINTR;
557 			break;
558 		case ERESTARTSYS:
559 			if (!(ka->sa.sa_flags & SA_RESTART)) {
560 				regs->regs[2] = EINTR;
561 				break;
562 			}
563 		/* fallthrough */
564 		case ERESTARTNOINTR:
565 			regs->regs[7] = regs->regs[26];
566 			regs->regs[2] = regs->regs[0];
567 			regs->cp0_epc -= 4;
568 		}
569 
570 		regs->regs[0] = 0;		/* Don't deal with this again.  */
571 	}
572 
573 	if (sig_uses_siginfo(ka))
574 		ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
575 					  ka, regs, sig, oldset, info);
576 	else
577 		ret = abi->setup_frame(vdso + abi->signal_return_offset,
578 				       ka, regs, sig, oldset);
579 
580 	if (ret)
581 		return ret;
582 
583 	spin_lock_irq(&current->sighand->siglock);
584 	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
585 	if (!(ka->sa.sa_flags & SA_NODEFER))
586 		sigaddset(&current->blocked, sig);
587 	recalc_sigpending();
588 	spin_unlock_irq(&current->sighand->siglock);
589 
590 	return ret;
591 }
592 
593 static void do_signal(struct pt_regs *regs)
594 {
595 	struct k_sigaction ka;
596 	sigset_t *oldset;
597 	siginfo_t info;
598 	int signr;
599 
600 	/*
601 	 * We want the common case to go fast, which is why we may in certain
602 	 * cases get here from kernel mode. Just return without doing anything
603 	 * if so.
604 	 */
605 	if (!user_mode(regs))
606 		return;
607 
608 	if (test_thread_flag(TIF_RESTORE_SIGMASK))
609 		oldset = &current->saved_sigmask;
610 	else
611 		oldset = &current->blocked;
612 
613 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
614 	if (signr > 0) {
615 		/* Whee!  Actually deliver the signal.  */
616 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
617 			/*
618 			 * A signal was successfully delivered; the saved
619 			 * sigmask will have been stored in the signal frame,
620 			 * and will be restored by sigreturn, so we can simply
621 			 * clear the TIF_RESTORE_SIGMASK flag.
622 			 */
623 			if (test_thread_flag(TIF_RESTORE_SIGMASK))
624 				clear_thread_flag(TIF_RESTORE_SIGMASK);
625 		}
626 
627 		return;
628 	}
629 
630 	if (regs->regs[0]) {
631 		if (regs->regs[2] == ERESTARTNOHAND ||
632 		    regs->regs[2] == ERESTARTSYS ||
633 		    regs->regs[2] == ERESTARTNOINTR) {
634 			regs->regs[2] = regs->regs[0];
635 			regs->regs[7] = regs->regs[26];
636 			regs->cp0_epc -= 4;
637 		}
638 		if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
639 			regs->regs[2] = current->thread.abi->restart;
640 			regs->regs[7] = regs->regs[26];
641 			regs->cp0_epc -= 4;
642 		}
643 		regs->regs[0] = 0;	/* Don't deal with this again.  */
644 	}
645 
646 	/*
647 	 * If there's no signal to deliver, we just put the saved sigmask
648 	 * back
649 	 */
650 	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
651 		clear_thread_flag(TIF_RESTORE_SIGMASK);
652 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
653 	}
654 }
655 
656 /*
657  * notification of userspace execution resumption
658  * - triggered by the TIF_WORK_MASK flags
659  */
660 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
661 	__u32 thread_info_flags)
662 {
663 	local_irq_enable();
664 
665 	/* deal with pending signal delivery */
666 	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
667 		do_signal(regs);
668 
669 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
670 		clear_thread_flag(TIF_NOTIFY_RESUME);
671 		tracehook_notify_resume(regs);
672 		if (current->replacement_session_keyring)
673 			key_replace_session_keyring();
674 	}
675 }
676 
677 #ifdef CONFIG_SMP
678 static int smp_save_fp_context(struct sigcontext __user *sc)
679 {
680 	return raw_cpu_has_fpu
681 	       ? _save_fp_context(sc)
682 	       : fpu_emulator_save_context(sc);
683 }
684 
685 static int smp_restore_fp_context(struct sigcontext __user *sc)
686 {
687 	return raw_cpu_has_fpu
688 	       ? _restore_fp_context(sc)
689 	       : fpu_emulator_restore_context(sc);
690 }
691 #endif
692 
693 static int signal_setup(void)
694 {
695 #ifdef CONFIG_SMP
696 	/* For now just do the cpu_has_fpu check when the functions are invoked */
697 	save_fp_context = smp_save_fp_context;
698 	restore_fp_context = smp_restore_fp_context;
699 #else
700 	if (cpu_has_fpu) {
701 		save_fp_context = _save_fp_context;
702 		restore_fp_context = _restore_fp_context;
703 	} else {
704 		save_fp_context = fpu_emulator_save_context;
705 		restore_fp_context = fpu_emulator_restore_context;
706 	}
707 #endif
708 
709 	return 0;
710 }
711 
712 arch_initcall(signal_setup);
713