Loading...
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
40static int (*save_fp_context)(struct sigcontext __user *sc);
41static int (*restore_fp_context)(struct sigcontext __user *sc);
42
43extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
44extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
45
46extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
47extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
48
49struct 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
56struct 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 */
66static 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
86static 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
106int 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
146int 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
165static int
166check_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
177int 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
222void __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
249asmlinkage 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(¤t->sighand->siglock);
260 current->saved_sigmask = current->blocked;
261 current->blocked = newset;
262 recalc_sigpending();
263 spin_unlock_irq(¤t->sighand->siglock);
264
265 current->state = TASK_INTERRUPTIBLE;
266 schedule();
267 set_thread_flag(TIF_RESTORE_SIGMASK);
268 return -ERESTARTNOHAND;
269}
270#endif
271
272asmlinkage 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(¤t->sighand->siglock);
289 current->saved_sigmask = current->blocked;
290 current->blocked = newset;
291 recalc_sigpending();
292 spin_unlock_irq(¤t->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
301SYSCALL_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
341asmlinkage 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
351asmlinkage 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(¤t->sighand->siglock);
365 current->blocked = blocked;
366 recalc_sigpending();
367 spin_unlock_irq(¤t->sighand->siglock);
368
369 sig = restore_sigcontext(®s, &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" (®s));
383 /* Unreached */
384
385badframe:
386 force_sig(SIGSEGV, current);
387}
388#endif /* CONFIG_TRAD_SIGNALS */
389
390asmlinkage 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(¤t->sighand->siglock);
404 current->blocked = set;
405 recalc_sigpending();
406 spin_unlock_irq(¤t->sighand->siglock);
407
408 sig = restore_sigcontext(®s, &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" (®s));
426 /* Unreached */
427
428badframe:
429 force_sig(SIGSEGV, current);
430}
431
432#ifdef CONFIG_TRAD_SIGNALS
433static 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
470give_sigsegv:
471 force_sigsegv(signr, current);
472 return -EFAULT;
473}
474#endif
475
476static 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
528give_sigsegv:
529 force_sigsegv(signr, current);
530 return -EFAULT;
531}
532
533struct 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
544static 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(¤t->sighand->siglock);
583 sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
584 if (!(ka->sa.sa_flags & SA_NODEFER))
585 sigaddset(¤t->blocked, sig);
586 recalc_sigpending();
587 spin_unlock_irq(¤t->sighand->siglock);
588
589 return ret;
590}
591
592static 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 = ¤t->saved_sigmask;
609 else
610 oldset = ¤t->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, ¤t->saved_sigmask, NULL);
652 }
653}
654
655/*
656 * notification of userspace execution resumption
657 * - triggered by the TIF_WORK_MASK flags
658 */
659asmlinkage 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
677static 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
684static 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
692static 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
711arch_initcall(signal_setup);
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
41static int (*save_fp_context)(struct sigcontext __user *sc);
42static int (*restore_fp_context)(struct sigcontext __user *sc);
43
44extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
45extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
46
47extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
48extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
49
50struct 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
57struct 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 */
67static 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
87static 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
107int 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
147int 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
166static int
167check_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
178int 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
223void __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
250asmlinkage 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 return sigsuspend(&newset);
259}
260#endif
261
262asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
263{
264 sigset_t newset;
265 sigset_t __user *unewset;
266 size_t sigsetsize;
267
268 /* XXX Don't preclude handling different sized sigset_t's. */
269 sigsetsize = regs.regs[5];
270 if (sigsetsize != sizeof(sigset_t))
271 return -EINVAL;
272
273 unewset = (sigset_t __user *) regs.regs[4];
274 if (copy_from_user(&newset, unewset, sizeof(newset)))
275 return -EFAULT;
276 return sigsuspend(&newset);
277}
278
279#ifdef CONFIG_TRAD_SIGNALS
280SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
281 struct sigaction __user *, oact)
282{
283 struct k_sigaction new_ka, old_ka;
284 int ret;
285 int err = 0;
286
287 if (act) {
288 old_sigset_t mask;
289
290 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
291 return -EFAULT;
292 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
293 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
294 err |= __get_user(mask, &act->sa_mask.sig[0]);
295 if (err)
296 return -EFAULT;
297
298 siginitset(&new_ka.sa.sa_mask, mask);
299 }
300
301 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
302
303 if (!ret && oact) {
304 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
305 return -EFAULT;
306 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
307 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
308 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
309 err |= __put_user(0, &oact->sa_mask.sig[1]);
310 err |= __put_user(0, &oact->sa_mask.sig[2]);
311 err |= __put_user(0, &oact->sa_mask.sig[3]);
312 if (err)
313 return -EFAULT;
314 }
315
316 return ret;
317}
318#endif
319
320asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
321{
322 const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
323 stack_t __user *uoss = (stack_t __user *) regs.regs[5];
324 unsigned long usp = regs.regs[29];
325
326 return do_sigaltstack(uss, uoss, usp);
327}
328
329#ifdef CONFIG_TRAD_SIGNALS
330asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
331{
332 struct sigframe __user *frame;
333 sigset_t blocked;
334 int sig;
335
336 frame = (struct sigframe __user *) regs.regs[29];
337 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
338 goto badframe;
339 if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
340 goto badframe;
341
342 set_current_blocked(&blocked);
343
344 sig = restore_sigcontext(®s, &frame->sf_sc);
345 if (sig < 0)
346 goto badframe;
347 else if (sig)
348 force_sig(sig, current);
349
350 /*
351 * Don't let your children do this ...
352 */
353 __asm__ __volatile__(
354 "move\t$29, %0\n\t"
355 "j\tsyscall_exit"
356 :/* no outputs */
357 :"r" (®s));
358 /* Unreached */
359
360badframe:
361 force_sig(SIGSEGV, current);
362}
363#endif /* CONFIG_TRAD_SIGNALS */
364
365asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
366{
367 struct rt_sigframe __user *frame;
368 sigset_t set;
369 int sig;
370
371 frame = (struct rt_sigframe __user *) regs.regs[29];
372 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
373 goto badframe;
374 if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
375 goto badframe;
376
377 set_current_blocked(&set);
378
379 sig = restore_sigcontext(®s, &frame->rs_uc.uc_mcontext);
380 if (sig < 0)
381 goto badframe;
382 else if (sig)
383 force_sig(sig, current);
384
385 /* It is more difficult to avoid calling this function than to
386 call it and ignore errors. */
387 do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
388
389 /*
390 * Don't let your children do this ...
391 */
392 __asm__ __volatile__(
393 "move\t$29, %0\n\t"
394 "j\tsyscall_exit"
395 :/* no outputs */
396 :"r" (®s));
397 /* Unreached */
398
399badframe:
400 force_sig(SIGSEGV, current);
401}
402
403#ifdef CONFIG_TRAD_SIGNALS
404static int setup_frame(void *sig_return, struct k_sigaction *ka,
405 struct pt_regs *regs, int signr, sigset_t *set)
406{
407 struct sigframe __user *frame;
408 int err = 0;
409
410 frame = get_sigframe(ka, regs, sizeof(*frame));
411 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
412 goto give_sigsegv;
413
414 err |= setup_sigcontext(regs, &frame->sf_sc);
415 err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
416 if (err)
417 goto give_sigsegv;
418
419 /*
420 * Arguments to signal handler:
421 *
422 * a0 = signal number
423 * a1 = 0 (should be cause)
424 * a2 = pointer to struct sigcontext
425 *
426 * $25 and c0_epc point to the signal handler, $29 points to the
427 * struct sigframe.
428 */
429 regs->regs[ 4] = signr;
430 regs->regs[ 5] = 0;
431 regs->regs[ 6] = (unsigned long) &frame->sf_sc;
432 regs->regs[29] = (unsigned long) frame;
433 regs->regs[31] = (unsigned long) sig_return;
434 regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
435
436 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
437 current->comm, current->pid,
438 frame, regs->cp0_epc, regs->regs[31]);
439 return 0;
440
441give_sigsegv:
442 force_sigsegv(signr, current);
443 return -EFAULT;
444}
445#endif
446
447static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
448 struct pt_regs *regs, int signr, sigset_t *set,
449 siginfo_t *info)
450{
451 struct rt_sigframe __user *frame;
452 int err = 0;
453
454 frame = get_sigframe(ka, regs, sizeof(*frame));
455 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
456 goto give_sigsegv;
457
458 /* Create siginfo. */
459 err |= copy_siginfo_to_user(&frame->rs_info, info);
460
461 /* Create the ucontext. */
462 err |= __put_user(0, &frame->rs_uc.uc_flags);
463 err |= __put_user(NULL, &frame->rs_uc.uc_link);
464 err |= __put_user((void __user *)current->sas_ss_sp,
465 &frame->rs_uc.uc_stack.ss_sp);
466 err |= __put_user(sas_ss_flags(regs->regs[29]),
467 &frame->rs_uc.uc_stack.ss_flags);
468 err |= __put_user(current->sas_ss_size,
469 &frame->rs_uc.uc_stack.ss_size);
470 err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
471 err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
472
473 if (err)
474 goto give_sigsegv;
475
476 /*
477 * Arguments to signal handler:
478 *
479 * a0 = signal number
480 * a1 = 0 (should be cause)
481 * a2 = pointer to ucontext
482 *
483 * $25 and c0_epc point to the signal handler, $29 points to
484 * the struct rt_sigframe.
485 */
486 regs->regs[ 4] = signr;
487 regs->regs[ 5] = (unsigned long) &frame->rs_info;
488 regs->regs[ 6] = (unsigned long) &frame->rs_uc;
489 regs->regs[29] = (unsigned long) frame;
490 regs->regs[31] = (unsigned long) sig_return;
491 regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
492
493 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
494 current->comm, current->pid,
495 frame, regs->cp0_epc, regs->regs[31]);
496
497 return 0;
498
499give_sigsegv:
500 force_sigsegv(signr, current);
501 return -EFAULT;
502}
503
504struct mips_abi mips_abi = {
505#ifdef CONFIG_TRAD_SIGNALS
506 .setup_frame = setup_frame,
507 .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
508#endif
509 .setup_rt_frame = setup_rt_frame,
510 .rt_signal_return_offset =
511 offsetof(struct mips_vdso, rt_signal_trampoline),
512 .restart = __NR_restart_syscall
513};
514
515static void handle_signal(unsigned long sig, siginfo_t *info,
516 struct k_sigaction *ka, struct pt_regs *regs)
517{
518 sigset_t *oldset = sigmask_to_save();
519 int ret;
520 struct mips_abi *abi = current->thread.abi;
521 void *vdso = current->mm->context.vdso;
522
523 if (regs->regs[0]) {
524 switch(regs->regs[2]) {
525 case ERESTART_RESTARTBLOCK:
526 case ERESTARTNOHAND:
527 regs->regs[2] = EINTR;
528 break;
529 case ERESTARTSYS:
530 if (!(ka->sa.sa_flags & SA_RESTART)) {
531 regs->regs[2] = EINTR;
532 break;
533 }
534 /* fallthrough */
535 case ERESTARTNOINTR:
536 regs->regs[7] = regs->regs[26];
537 regs->regs[2] = regs->regs[0];
538 regs->cp0_epc -= 4;
539 }
540
541 regs->regs[0] = 0; /* Don't deal with this again. */
542 }
543
544 if (sig_uses_siginfo(ka))
545 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
546 ka, regs, sig, oldset, info);
547 else
548 ret = abi->setup_frame(vdso + abi->signal_return_offset,
549 ka, regs, sig, oldset);
550
551 if (ret)
552 return;
553
554 signal_delivered(sig, info, ka, regs, 0);
555}
556
557static void do_signal(struct pt_regs *regs)
558{
559 struct k_sigaction ka;
560 siginfo_t info;
561 int signr;
562
563 /*
564 * We want the common case to go fast, which is why we may in certain
565 * cases get here from kernel mode. Just return without doing anything
566 * if so.
567 */
568 if (!user_mode(regs))
569 return;
570
571 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
572 if (signr > 0) {
573 /* Whee! Actually deliver the signal. */
574 handle_signal(signr, &info, &ka, regs);
575 return;
576 }
577
578 if (regs->regs[0]) {
579 if (regs->regs[2] == ERESTARTNOHAND ||
580 regs->regs[2] == ERESTARTSYS ||
581 regs->regs[2] == ERESTARTNOINTR) {
582 regs->regs[2] = regs->regs[0];
583 regs->regs[7] = regs->regs[26];
584 regs->cp0_epc -= 4;
585 }
586 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
587 regs->regs[2] = current->thread.abi->restart;
588 regs->regs[7] = regs->regs[26];
589 regs->cp0_epc -= 4;
590 }
591 regs->regs[0] = 0; /* Don't deal with this again. */
592 }
593
594 /*
595 * If there's no signal to deliver, we just put the saved sigmask
596 * back
597 */
598 restore_saved_sigmask();
599}
600
601/*
602 * notification of userspace execution resumption
603 * - triggered by the TIF_WORK_MASK flags
604 */
605asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
606 __u32 thread_info_flags)
607{
608 local_irq_enable();
609
610 /* deal with pending signal delivery */
611 if (thread_info_flags & _TIF_SIGPENDING)
612 do_signal(regs);
613
614 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
615 clear_thread_flag(TIF_NOTIFY_RESUME);
616 tracehook_notify_resume(regs);
617 }
618}
619
620#ifdef CONFIG_SMP
621static int smp_save_fp_context(struct sigcontext __user *sc)
622{
623 return raw_cpu_has_fpu
624 ? _save_fp_context(sc)
625 : fpu_emulator_save_context(sc);
626}
627
628static int smp_restore_fp_context(struct sigcontext __user *sc)
629{
630 return raw_cpu_has_fpu
631 ? _restore_fp_context(sc)
632 : fpu_emulator_restore_context(sc);
633}
634#endif
635
636static int signal_setup(void)
637{
638#ifdef CONFIG_SMP
639 /* For now just do the cpu_has_fpu check when the functions are invoked */
640 save_fp_context = smp_save_fp_context;
641 restore_fp_context = smp_restore_fp_context;
642#else
643 if (cpu_has_fpu) {
644 save_fp_context = _save_fp_context;
645 restore_fp_context = _restore_fp_context;
646 } else {
647 save_fp_context = fpu_emulator_save_context;
648 restore_fp_context = fpu_emulator_restore_context;
649 }
650#endif
651
652 return 0;
653}
654
655arch_initcall(signal_setup);