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1 /*
2 * linux/arch/sh/kernel/signal.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
7 *
8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
9 *
10 */
11 #include <linux/sched.h>
12 #include <linux/mm.h>
13 #include <linux/smp.h>
14 #include <linux/smp_lock.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/stddef.h>
22 #include <linux/tty.h>
23 #include <linux/elf.h>
24 #include <linux/personality.h>
25 #include <linux/binfmts.h>
26
27 #include <asm/ucontext.h>
28 #include <asm/uaccess.h>
29 #include <asm/pgtable.h>
30 #include <asm/cacheflush.h>
31
32 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
33
34 /*
35 * Atomically swap in the new signal mask, and wait for a signal.
36 */
37 asmlinkage int
38 sys_sigsuspend(old_sigset_t mask,
39 unsigned long r5, unsigned long r6, unsigned long r7,
40 struct pt_regs __regs)
41 {
42 mask &= _BLOCKABLE;
43 spin_lock_irq(&current->sighand->siglock);
44 current->saved_sigmask = current->blocked;
45 siginitset(&current->blocked, mask);
46 recalc_sigpending();
47 spin_unlock_irq(&current->sighand->siglock);
48
49 current->state = TASK_INTERRUPTIBLE;
50 schedule();
51 set_thread_flag(TIF_RESTORE_SIGMASK);
52 return -ERESTARTNOHAND;
53 }
54
55 asmlinkage int
56 sys_sigaction(int sig, const struct old_sigaction __user *act,
57 struct old_sigaction __user *oact)
58 {
59 struct k_sigaction new_ka, old_ka;
60 int ret;
61
62 if (act) {
63 old_sigset_t mask;
64 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
65 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
66 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
67 return -EFAULT;
68 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
69 __get_user(mask, &act->sa_mask);
70 siginitset(&new_ka.sa.sa_mask, mask);
71 }
72
73 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
74
75 if (!ret && oact) {
76 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
77 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
78 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
79 return -EFAULT;
80 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
81 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
82 }
83
84 return ret;
85 }
86
87 asmlinkage int
88 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
89 unsigned long r6, unsigned long r7,
90 struct pt_regs __regs)
91 {
92 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
93
94 return do_sigaltstack(uss, uoss, regs->regs[15]);
95 }
96
97
98 /*
99 * Do a signal return; undo the signal stack.
100 */
101
102 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
103 #if defined(CONFIG_CPU_SH2) || defined(CONFIG_CPU_SH2A)
104 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */
105 #else
106 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */
107 #endif
108 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */
109
110 struct sigframe
111 {
112 struct sigcontext sc;
113 unsigned long extramask[_NSIG_WORDS-1];
114 u16 retcode[8];
115 };
116
117 struct rt_sigframe
118 {
119 struct siginfo info;
120 struct ucontext uc;
121 u16 retcode[8];
122 };
123
124 #ifdef CONFIG_SH_FPU
125 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
126 {
127 struct task_struct *tsk = current;
128
129 if (!(cpu_data->flags & CPU_HAS_FPU))
130 return 0;
131
132 set_used_math();
133 return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],
134 sizeof(long)*(16*2+2));
135 }
136
137 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
138 struct pt_regs *regs)
139 {
140 struct task_struct *tsk = current;
141
142 if (!(cpu_data->flags & CPU_HAS_FPU))
143 return 0;
144
145 if (!used_math()) {
146 __put_user(0, &sc->sc_ownedfp);
147 return 0;
148 }
149
150 __put_user(1, &sc->sc_ownedfp);
151
152 /* This will cause a "finit" to be triggered by the next
153 attempted FPU operation by the 'current' process.
154 */
155 clear_used_math();
156
157 unlazy_fpu(tsk, regs);
158 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,
159 sizeof(long)*(16*2+2));
160 }
161 #endif /* CONFIG_SH_FPU */
162
163 static int
164 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
165 {
166 unsigned int err = 0;
167
168 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
169 COPY(regs[1]);
170 COPY(regs[2]); COPY(regs[3]);
171 COPY(regs[4]); COPY(regs[5]);
172 COPY(regs[6]); COPY(regs[7]);
173 COPY(regs[8]); COPY(regs[9]);
174 COPY(regs[10]); COPY(regs[11]);
175 COPY(regs[12]); COPY(regs[13]);
176 COPY(regs[14]); COPY(regs[15]);
177 COPY(gbr); COPY(mach);
178 COPY(macl); COPY(pr);
179 COPY(sr); COPY(pc);
180 #undef COPY
181
182 #ifdef CONFIG_SH_FPU
183 if (cpu_data->flags & CPU_HAS_FPU) {
184 int owned_fp;
185 struct task_struct *tsk = current;
186
187 regs->sr |= SR_FD; /* Release FPU */
188 clear_fpu(tsk, regs);
189 clear_used_math();
190 __get_user (owned_fp, &sc->sc_ownedfp);
191 if (owned_fp)
192 err |= restore_sigcontext_fpu(sc);
193 }
194 #endif
195
196 regs->tra = -1; /* disable syscall checks */
197 err |= __get_user(*r0_p, &sc->sc_regs[0]);
198 return err;
199 }
200
201 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
202 unsigned long r6, unsigned long r7,
203 struct pt_regs __regs)
204 {
205 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
206 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
207 sigset_t set;
208 int r0;
209
210 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
211 goto badframe;
212
213 if (__get_user(set.sig[0], &frame->sc.oldmask)
214 || (_NSIG_WORDS > 1
215 && __copy_from_user(&set.sig[1], &frame->extramask,
216 sizeof(frame->extramask))))
217 goto badframe;
218
219 sigdelsetmask(&set, ~_BLOCKABLE);
220
221 spin_lock_irq(&current->sighand->siglock);
222 current->blocked = set;
223 recalc_sigpending();
224 spin_unlock_irq(&current->sighand->siglock);
225
226 if (restore_sigcontext(regs, &frame->sc, &r0))
227 goto badframe;
228 return r0;
229
230 badframe:
231 force_sig(SIGSEGV, current);
232 return 0;
233 }
234
235 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
236 unsigned long r6, unsigned long r7,
237 struct pt_regs __regs)
238 {
239 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
240 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
241 sigset_t set;
242 stack_t st;
243 int r0;
244
245 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
246 goto badframe;
247
248 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
249 goto badframe;
250
251 sigdelsetmask(&set, ~_BLOCKABLE);
252 spin_lock_irq(&current->sighand->siglock);
253 current->blocked = set;
254 recalc_sigpending();
255 spin_unlock_irq(&current->sighand->siglock);
256
257 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
258 goto badframe;
259
260 if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
261 goto badframe;
262 /* It is more difficult to avoid calling this function than to
263 call it and ignore errors. */
264 do_sigaltstack(&st, NULL, regs->regs[15]);
265
266 return r0;
267
268 badframe:
269 force_sig(SIGSEGV, current);
270 return 0;
271 }
272
273 /*
274 * Set up a signal frame.
275 */
276
277 static int
278 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
279 unsigned long mask)
280 {
281 int err = 0;
282
283 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
284 COPY(regs[0]); COPY(regs[1]);
285 COPY(regs[2]); COPY(regs[3]);
286 COPY(regs[4]); COPY(regs[5]);
287 COPY(regs[6]); COPY(regs[7]);
288 COPY(regs[8]); COPY(regs[9]);
289 COPY(regs[10]); COPY(regs[11]);
290 COPY(regs[12]); COPY(regs[13]);
291 COPY(regs[14]); COPY(regs[15]);
292 COPY(gbr); COPY(mach);
293 COPY(macl); COPY(pr);
294 COPY(sr); COPY(pc);
295 #undef COPY
296
297 #ifdef CONFIG_SH_FPU
298 err |= save_sigcontext_fpu(sc, regs);
299 #endif
300
301 /* non-iBCS2 extensions.. */
302 err |= __put_user(mask, &sc->oldmask);
303
304 return err;
305 }
306
307 /*
308 * Determine which stack to use..
309 */
310 static inline void __user *
311 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
312 {
313 if (ka->sa.sa_flags & SA_ONSTACK) {
314 if (sas_ss_flags(sp) == 0)
315 sp = current->sas_ss_sp + current->sas_ss_size;
316 }
317
318 return (void __user *)((sp - frame_size) & -8ul);
319 }
320
321 /* These symbols are defined with the addresses in the vsyscall page.
322 See vsyscall-trapa.S. */
323 extern void __user __kernel_sigreturn;
324 extern void __user __kernel_rt_sigreturn;
325
326 static int setup_frame(int sig, struct k_sigaction *ka,
327 sigset_t *set, struct pt_regs *regs)
328 {
329 struct sigframe __user *frame;
330 int err = 0;
331 int signal;
332
333 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
334
335 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
336 goto give_sigsegv;
337
338 signal = current_thread_info()->exec_domain
339 && current_thread_info()->exec_domain->signal_invmap
340 && sig < 32
341 ? current_thread_info()->exec_domain->signal_invmap[sig]
342 : sig;
343
344 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
345
346 if (_NSIG_WORDS > 1)
347 err |= __copy_to_user(frame->extramask, &set->sig[1],
348 sizeof(frame->extramask));
349
350 /* Set up to return from userspace. If provided, use a stub
351 already in userspace. */
352 if (ka->sa.sa_flags & SA_RESTORER) {
353 regs->pr = (unsigned long) ka->sa.sa_restorer;
354 #ifdef CONFIG_VSYSCALL
355 } else if (likely(current->mm->context.vdso)) {
356 regs->pr = VDSO_SYM(&__kernel_sigreturn);
357 #endif
358 } else {
359 /* Generate return code (system call to sigreturn) */
360 err |= __put_user(MOVW(7), &frame->retcode[0]);
361 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
362 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
363 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
364 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
365 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
366 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
367 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
368 regs->pr = (unsigned long) frame->retcode;
369 }
370
371 if (err)
372 goto give_sigsegv;
373
374 /* Set up registers for signal handler */
375 regs->regs[15] = (unsigned long) frame;
376 regs->regs[4] = signal; /* Arg for signal handler */
377 regs->regs[5] = 0;
378 regs->regs[6] = (unsigned long) &frame->sc;
379 regs->pc = (unsigned long) ka->sa.sa_handler;
380
381 set_fs(USER_DS);
382
383 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
384 current->comm, current->pid, frame, regs->pc, regs->pr);
385
386 flush_cache_sigtramp(regs->pr);
387
388 if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
389 flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
390
391 return 0;
392
393 give_sigsegv:
394 force_sigsegv(sig, current);
395 return -EFAULT;
396 }
397
398 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
399 sigset_t *set, struct pt_regs *regs)
400 {
401 struct rt_sigframe __user *frame;
402 int err = 0;
403 int signal;
404
405 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
406
407 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
408 goto give_sigsegv;
409
410 signal = current_thread_info()->exec_domain
411 && current_thread_info()->exec_domain->signal_invmap
412 && sig < 32
413 ? current_thread_info()->exec_domain->signal_invmap[sig]
414 : sig;
415
416 err |= copy_siginfo_to_user(&frame->info, info);
417
418 /* Create the ucontext. */
419 err |= __put_user(0, &frame->uc.uc_flags);
420 err |= __put_user(0, &frame->uc.uc_link);
421 err |= __put_user((void *)current->sas_ss_sp,
422 &frame->uc.uc_stack.ss_sp);
423 err |= __put_user(sas_ss_flags(regs->regs[15]),
424 &frame->uc.uc_stack.ss_flags);
425 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
426 err |= setup_sigcontext(&frame->uc.uc_mcontext,
427 regs, set->sig[0]);
428 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
429
430 /* Set up to return from userspace. If provided, use a stub
431 already in userspace. */
432 if (ka->sa.sa_flags & SA_RESTORER) {
433 regs->pr = (unsigned long) ka->sa.sa_restorer;
434 #ifdef CONFIG_VSYSCALL
435 } else if (likely(current->mm->context.vdso)) {
436 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
437 #endif
438 } else {
439 /* Generate return code (system call to rt_sigreturn) */
440 err |= __put_user(MOVW(7), &frame->retcode[0]);
441 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
442 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
443 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
444 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
445 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
446 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
447 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
448 regs->pr = (unsigned long) frame->retcode;
449 }
450
451 if (err)
452 goto give_sigsegv;
453
454 /* Set up registers for signal handler */
455 regs->regs[15] = (unsigned long) frame;
456 regs->regs[4] = signal; /* Arg for signal handler */
457 regs->regs[5] = (unsigned long) &frame->info;
458 regs->regs[6] = (unsigned long) &frame->uc;
459 regs->pc = (unsigned long) ka->sa.sa_handler;
460
461 set_fs(USER_DS);
462
463 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
464 current->comm, current->pid, frame, regs->pc, regs->pr);
465
466 flush_cache_sigtramp(regs->pr);
467
468 if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
469 flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
470
471 return 0;
472
473 give_sigsegv:
474 force_sigsegv(sig, current);
475 return -EFAULT;
476 }
477
478 /*
479 * OK, we're invoking a handler
480 */
481
482 static int
483 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
484 sigset_t *oldset, struct pt_regs *regs)
485 {
486 int ret;
487
488 /* Are we from a system call? */
489 if (regs->tra >= 0) {
490 /* If so, check system call restarting.. */
491 switch (regs->regs[0]) {
492 case -ERESTARTNOHAND:
493 regs->regs[0] = -EINTR;
494 break;
495
496 case -ERESTARTSYS:
497 if (!(ka->sa.sa_flags & SA_RESTART)) {
498 regs->regs[0] = -EINTR;
499 break;
500 }
501 /* fallthrough */
502 case -ERESTARTNOINTR:
503 regs->pc -= 2;
504 }
505 } else {
506 /* gUSA handling */
507 #ifdef CONFIG_PREEMPT
508 unsigned long flags;
509
510 local_irq_save(flags);
511 #endif
512 if (regs->regs[15] >= 0xc0000000) {
513 int offset = (int)regs->regs[15];
514
515 /* Reset stack pointer: clear critical region mark */
516 regs->regs[15] = regs->regs[1];
517 if (regs->pc < regs->regs[0])
518 /* Go to rewind point #1 */
519 regs->pc = regs->regs[0] + offset - 2;
520 }
521 #ifdef CONFIG_PREEMPT
522 local_irq_restore(flags);
523 #endif
524 }
525
526 /* Set up the stack frame */
527 if (ka->sa.sa_flags & SA_SIGINFO)
528 ret = setup_rt_frame(sig, ka, info, oldset, regs);
529 else
530 ret = setup_frame(sig, ka, oldset, regs);
531
532 if (ka->sa.sa_flags & SA_ONESHOT)
533 ka->sa.sa_handler = SIG_DFL;
534
535 if (ret == 0) {
536 spin_lock_irq(&current->sighand->siglock);
537 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
538 if (!(ka->sa.sa_flags & SA_NODEFER))
539 sigaddset(&current->blocked,sig);
540 recalc_sigpending();
541 spin_unlock_irq(&current->sighand->siglock);
542 }
543
544 return ret;
545 }
546
547 /*
548 * Note that 'init' is a special process: it doesn't get signals it doesn't
549 * want to handle. Thus you cannot kill init even with a SIGKILL even by
550 * mistake.
551 *
552 * Note that we go through the signals twice: once to check the signals that
553 * the kernel can handle, and then we build all the user-level signal handling
554 * stack-frames in one go after that.
555 */
556 static void do_signal(struct pt_regs *regs, unsigned int save_r0)
557 {
558 siginfo_t info;
559 int signr;
560 struct k_sigaction ka;
561 sigset_t *oldset;
562
563 /*
564 * We want the common case to go fast, which
565 * is why we may in certain cases get here from
566 * kernel mode. Just return without doing anything
567 * if so.
568 */
569 if (!user_mode(regs))
570 return;
571
572 if (try_to_freeze())
573 goto no_signal;
574
575 if (test_thread_flag(TIF_RESTORE_SIGMASK))
576 oldset = &current->saved_sigmask;
577 else
578 oldset = &current->blocked;
579
580 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
581 if (signr > 0) {
582 /* Whee! Actually deliver the signal. */
583 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
584 /* a signal was successfully delivered; the saved
585 * sigmask will have been stored in the signal frame,
586 * and will be restored by sigreturn, so we can simply
587 * clear the TIF_RESTORE_SIGMASK flag */
588 if (test_thread_flag(TIF_RESTORE_SIGMASK))
589 clear_thread_flag(TIF_RESTORE_SIGMASK);
590 }
591 }
592
593 no_signal:
594 /* Did we come from a system call? */
595 if (regs->tra >= 0) {
596 /* Restart the system call - no handlers present */
597 if (regs->regs[0] == -ERESTARTNOHAND ||
598 regs->regs[0] == -ERESTARTSYS ||
599 regs->regs[0] == -ERESTARTNOINTR) {
600 regs->regs[0] = save_r0;
601 regs->pc -= 2;
602 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
603 regs->pc -= 2;
604 regs->regs[3] = __NR_restart_syscall;
605 }
606 }
607
608 /* if there's no signal to deliver, we just put the saved sigmask
609 * back */
610 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
611 clear_thread_flag(TIF_RESTORE_SIGMASK);
612 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
613 }
614 }
615
616 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
617 __u32 thread_info_flags)
618 {
619 /* deal with pending signal delivery */
620 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
621 do_signal(regs, save_r0);
622 }