1 /* signal.c: FRV specific bits of signal handling
2 *
3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from arch/m68k/kernel/signal.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13 #include <linux/sched.h>
14 #include <linux/mm.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/personality.h>
23 #include <linux/freezer.h>
24 #include <linux/tracehook.h>
25 #include <asm/ucontext.h>
26 #include <asm/uaccess.h>
27 #include <asm/cacheflush.h>
28
29 #define DEBUG_SIG 0
30
31 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
32
33 struct fdpic_func_descriptor {
34 unsigned long text;
35 unsigned long GOT;
36 };
37
38 /*
39 * Atomically swap in the new signal mask, and wait for a signal.
40 */
sys_sigsuspend(int history0,int history1,old_sigset_t mask)41 asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
42 {
43 mask &= _BLOCKABLE;
44 spin_lock_irq(¤t->sighand->siglock);
45 current->saved_sigmask = current->blocked;
46 siginitset(¤t->blocked, mask);
47 recalc_sigpending();
48 spin_unlock_irq(¤t->sighand->siglock);
49
50 current->state = TASK_INTERRUPTIBLE;
51 schedule();
52 set_thread_flag(TIF_RESTORE_SIGMASK);
53 return -ERESTARTNOHAND;
54 }
55
sys_sigaction(int sig,const struct old_sigaction __user * act,struct old_sigaction __user * oact)56 asmlinkage int sys_sigaction(int sig,
57 const struct old_sigaction __user *act,
58 struct old_sigaction __user *oact)
59 {
60 struct k_sigaction new_ka, old_ka;
61 int ret;
62
63 if (act) {
64 old_sigset_t mask;
65 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
66 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
67 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
68 return -EFAULT;
69 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
70 __get_user(mask, &act->sa_mask);
71 siginitset(&new_ka.sa.sa_mask, mask);
72 }
73
74 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
75
76 if (!ret && oact) {
77 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
78 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
79 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
80 return -EFAULT;
81 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
82 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
83 }
84
85 return ret;
86 }
87
88 asmlinkage
sys_sigaltstack(const stack_t __user * uss,stack_t __user * uoss)89 int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
90 {
91 return do_sigaltstack(uss, uoss, __frame->sp);
92 }
93
94
95 /*
96 * Do a signal return; undo the signal stack.
97 */
98
99 struct sigframe
100 {
101 __sigrestore_t pretcode;
102 int sig;
103 struct sigcontext sc;
104 unsigned long extramask[_NSIG_WORDS-1];
105 uint32_t retcode[2];
106 };
107
108 struct rt_sigframe
109 {
110 __sigrestore_t pretcode;
111 int sig;
112 struct siginfo __user *pinfo;
113 void __user *puc;
114 struct siginfo info;
115 struct ucontext uc;
116 uint32_t retcode[2];
117 };
118
restore_sigcontext(struct sigcontext __user * sc,int * _gr8)119 static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
120 {
121 struct user_context *user = current->thread.user;
122 unsigned long tbr, psr;
123
124 /* Always make any pending restarted system calls return -EINTR */
125 current_thread_info()->restart_block.fn = do_no_restart_syscall;
126
127 tbr = user->i.tbr;
128 psr = user->i.psr;
129 if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
130 goto badframe;
131 user->i.tbr = tbr;
132 user->i.psr = psr;
133
134 restore_user_regs(user);
135
136 user->i.syscallno = -1; /* disable syscall checks */
137
138 *_gr8 = user->i.gr[8];
139 return 0;
140
141 badframe:
142 return 1;
143 }
144
sys_sigreturn(void)145 asmlinkage int sys_sigreturn(void)
146 {
147 struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
148 sigset_t set;
149 int gr8;
150
151 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
152 goto badframe;
153 if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
154 goto badframe;
155
156 if (_NSIG_WORDS > 1 &&
157 __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
158 goto badframe;
159
160 sigdelsetmask(&set, ~_BLOCKABLE);
161 spin_lock_irq(¤t->sighand->siglock);
162 current->blocked = set;
163 recalc_sigpending();
164 spin_unlock_irq(¤t->sighand->siglock);
165
166 if (restore_sigcontext(&frame->sc, &gr8))
167 goto badframe;
168 return gr8;
169
170 badframe:
171 force_sig(SIGSEGV, current);
172 return 0;
173 }
174
sys_rt_sigreturn(void)175 asmlinkage int sys_rt_sigreturn(void)
176 {
177 struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
178 sigset_t set;
179 int gr8;
180
181 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
182 goto badframe;
183 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
184 goto badframe;
185
186 sigdelsetmask(&set, ~_BLOCKABLE);
187 spin_lock_irq(¤t->sighand->siglock);
188 current->blocked = set;
189 recalc_sigpending();
190 spin_unlock_irq(¤t->sighand->siglock);
191
192 if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
193 goto badframe;
194
195 if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
196 goto badframe;
197
198 return gr8;
199
200 badframe:
201 force_sig(SIGSEGV, current);
202 return 0;
203 }
204
205 /*
206 * Set up a signal frame
207 */
setup_sigcontext(struct sigcontext __user * sc,unsigned long mask)208 static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
209 {
210 save_user_regs(current->thread.user);
211
212 if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
213 goto badframe;
214
215 /* non-iBCS2 extensions.. */
216 if (__put_user(mask, &sc->sc_oldmask) < 0)
217 goto badframe;
218
219 return 0;
220
221 badframe:
222 return 1;
223 }
224
225 /*****************************************************************************/
226 /*
227 * Determine which stack to use..
228 */
get_sigframe(struct k_sigaction * ka,size_t frame_size)229 static inline void __user *get_sigframe(struct k_sigaction *ka,
230 size_t frame_size)
231 {
232 unsigned long sp;
233
234 /* Default to using normal stack */
235 sp = __frame->sp;
236
237 /* This is the X/Open sanctioned signal stack switching. */
238 if (ka->sa.sa_flags & SA_ONSTACK) {
239 if (! sas_ss_flags(sp))
240 sp = current->sas_ss_sp + current->sas_ss_size;
241 }
242
243 return (void __user *) ((sp - frame_size) & ~7UL);
244
245 } /* end get_sigframe() */
246
247 /*****************************************************************************/
248 /*
249 *
250 */
setup_frame(int sig,struct k_sigaction * ka,sigset_t * set)251 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
252 {
253 struct sigframe __user *frame;
254 int rsig;
255
256 set_fs(USER_DS);
257
258 frame = get_sigframe(ka, sizeof(*frame));
259
260 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
261 goto give_sigsegv;
262
263 rsig = sig;
264 if (sig < 32 &&
265 __current_thread_info->exec_domain &&
266 __current_thread_info->exec_domain->signal_invmap)
267 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
268
269 if (__put_user(rsig, &frame->sig) < 0)
270 goto give_sigsegv;
271
272 if (setup_sigcontext(&frame->sc, set->sig[0]))
273 goto give_sigsegv;
274
275 if (_NSIG_WORDS > 1) {
276 if (__copy_to_user(frame->extramask, &set->sig[1],
277 sizeof(frame->extramask)))
278 goto give_sigsegv;
279 }
280
281 /* Set up to return from userspace. If provided, use a stub
282 * already in userspace. */
283 if (ka->sa.sa_flags & SA_RESTORER) {
284 if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
285 goto give_sigsegv;
286 }
287 else {
288 /* Set up the following code on the stack:
289 * setlos #__NR_sigreturn,gr7
290 * tira gr0,0
291 */
292 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
293 __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
294 __put_user(0xc0700000, &frame->retcode[1]))
295 goto give_sigsegv;
296
297 flush_icache_range((unsigned long) frame->retcode,
298 (unsigned long) (frame->retcode + 2));
299 }
300
301 /* Set up registers for the signal handler */
302 if (current->personality & FDPIC_FUNCPTRS) {
303 struct fdpic_func_descriptor __user *funcptr =
304 (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
305 struct fdpic_func_descriptor desc;
306 if (copy_from_user(&desc, funcptr, sizeof(desc)))
307 goto give_sigsegv;
308 __frame->pc = desc.text;
309 __frame->gr15 = desc.GOT;
310 } else {
311 __frame->pc = (unsigned long) ka->sa.sa_handler;
312 __frame->gr15 = 0;
313 }
314
315 __frame->sp = (unsigned long) frame;
316 __frame->lr = (unsigned long) &frame->retcode;
317 __frame->gr8 = sig;
318
319 /* the tracer may want to single-step inside the handler */
320 if (test_thread_flag(TIF_SINGLESTEP))
321 ptrace_notify(SIGTRAP);
322
323 #if DEBUG_SIG
324 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
325 sig, current->comm, current->pid, frame, __frame->pc,
326 frame->pretcode);
327 #endif
328
329 return 0;
330
331 give_sigsegv:
332 force_sigsegv(sig, current);
333 return -EFAULT;
334
335 } /* end setup_frame() */
336
337 /*****************************************************************************/
338 /*
339 *
340 */
setup_rt_frame(int sig,struct k_sigaction * ka,siginfo_t * info,sigset_t * set)341 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
342 sigset_t *set)
343 {
344 struct rt_sigframe __user *frame;
345 int rsig;
346
347 set_fs(USER_DS);
348
349 frame = get_sigframe(ka, sizeof(*frame));
350
351 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
352 goto give_sigsegv;
353
354 rsig = sig;
355 if (sig < 32 &&
356 __current_thread_info->exec_domain &&
357 __current_thread_info->exec_domain->signal_invmap)
358 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
359
360 if (__put_user(rsig, &frame->sig) ||
361 __put_user(&frame->info, &frame->pinfo) ||
362 __put_user(&frame->uc, &frame->puc))
363 goto give_sigsegv;
364
365 if (copy_siginfo_to_user(&frame->info, info))
366 goto give_sigsegv;
367
368 /* Create the ucontext. */
369 if (__put_user(0, &frame->uc.uc_flags) ||
370 __put_user(NULL, &frame->uc.uc_link) ||
371 __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
372 __put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) ||
373 __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
374 goto give_sigsegv;
375
376 if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
377 goto give_sigsegv;
378
379 if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
380 goto give_sigsegv;
381
382 /* Set up to return from userspace. If provided, use a stub
383 * already in userspace. */
384 if (ka->sa.sa_flags & SA_RESTORER) {
385 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
386 goto give_sigsegv;
387 }
388 else {
389 /* Set up the following code on the stack:
390 * setlos #__NR_sigreturn,gr7
391 * tira gr0,0
392 */
393 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
394 __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
395 __put_user(0xc0700000, &frame->retcode[1]))
396 goto give_sigsegv;
397
398 flush_icache_range((unsigned long) frame->retcode,
399 (unsigned long) (frame->retcode + 2));
400 }
401
402 /* Set up registers for signal handler */
403 if (current->personality & FDPIC_FUNCPTRS) {
404 struct fdpic_func_descriptor __user *funcptr =
405 (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
406 struct fdpic_func_descriptor desc;
407 if (copy_from_user(&desc, funcptr, sizeof(desc)))
408 goto give_sigsegv;
409 __frame->pc = desc.text;
410 __frame->gr15 = desc.GOT;
411 } else {
412 __frame->pc = (unsigned long) ka->sa.sa_handler;
413 __frame->gr15 = 0;
414 }
415
416 __frame->sp = (unsigned long) frame;
417 __frame->lr = (unsigned long) &frame->retcode;
418 __frame->gr8 = sig;
419 __frame->gr9 = (unsigned long) &frame->info;
420
421 /* the tracer may want to single-step inside the handler */
422 if (test_thread_flag(TIF_SINGLESTEP))
423 ptrace_notify(SIGTRAP);
424
425 #if DEBUG_SIG
426 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
427 sig, current->comm, current->pid, frame, __frame->pc,
428 frame->pretcode);
429 #endif
430
431 return 0;
432
433 give_sigsegv:
434 force_sigsegv(sig, current);
435 return -EFAULT;
436
437 } /* end setup_rt_frame() */
438
439 /*****************************************************************************/
440 /*
441 * OK, we're invoking a handler
442 */
handle_signal(unsigned long sig,siginfo_t * info,struct k_sigaction * ka,sigset_t * oldset)443 static int handle_signal(unsigned long sig, siginfo_t *info,
444 struct k_sigaction *ka, sigset_t *oldset)
445 {
446 int ret;
447
448 /* Are we from a system call? */
449 if (__frame->syscallno != -1) {
450 /* If so, check system call restarting.. */
451 switch (__frame->gr8) {
452 case -ERESTART_RESTARTBLOCK:
453 case -ERESTARTNOHAND:
454 __frame->gr8 = -EINTR;
455 break;
456
457 case -ERESTARTSYS:
458 if (!(ka->sa.sa_flags & SA_RESTART)) {
459 __frame->gr8 = -EINTR;
460 break;
461 }
462
463 /* fallthrough */
464 case -ERESTARTNOINTR:
465 __frame->gr8 = __frame->orig_gr8;
466 __frame->pc -= 4;
467 }
468 __frame->syscallno = -1;
469 }
470
471 /* Set up the stack frame */
472 if (ka->sa.sa_flags & SA_SIGINFO)
473 ret = setup_rt_frame(sig, ka, info, oldset);
474 else
475 ret = setup_frame(sig, ka, oldset);
476
477 if (ret == 0) {
478 spin_lock_irq(¤t->sighand->siglock);
479 sigorsets(¤t->blocked, ¤t->blocked,
480 &ka->sa.sa_mask);
481 if (!(ka->sa.sa_flags & SA_NODEFER))
482 sigaddset(¤t->blocked, sig);
483 recalc_sigpending();
484 spin_unlock_irq(¤t->sighand->siglock);
485 }
486
487 return ret;
488
489 } /* end handle_signal() */
490
491 /*****************************************************************************/
492 /*
493 * Note that 'init' is a special process: it doesn't get signals it doesn't
494 * want to handle. Thus you cannot kill init even with a SIGKILL even by
495 * mistake.
496 */
do_signal(void)497 static void do_signal(void)
498 {
499 struct k_sigaction ka;
500 siginfo_t info;
501 sigset_t *oldset;
502 int signr;
503
504 /*
505 * We want the common case to go fast, which
506 * is why we may in certain cases get here from
507 * kernel mode. Just return without doing anything
508 * if so.
509 */
510 if (!user_mode(__frame))
511 return;
512
513 if (try_to_freeze())
514 goto no_signal;
515
516 if (test_thread_flag(TIF_RESTORE_SIGMASK))
517 oldset = ¤t->saved_sigmask;
518 else
519 oldset = ¤t->blocked;
520
521 signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
522 if (signr > 0) {
523 if (handle_signal(signr, &info, &ka, oldset) == 0) {
524 /* a signal was successfully delivered; the saved
525 * sigmask will have been stored in the signal frame,
526 * and will be restored by sigreturn, so we can simply
527 * clear the TIF_RESTORE_SIGMASK flag */
528 if (test_thread_flag(TIF_RESTORE_SIGMASK))
529 clear_thread_flag(TIF_RESTORE_SIGMASK);
530
531 tracehook_signal_handler(signr, &info, &ka, __frame,
532 test_thread_flag(TIF_SINGLESTEP));
533 }
534
535 return;
536 }
537
538 no_signal:
539 /* Did we come from a system call? */
540 if (__frame->syscallno != -1) {
541 /* Restart the system call - no handlers present */
542 switch (__frame->gr8) {
543 case -ERESTARTNOHAND:
544 case -ERESTARTSYS:
545 case -ERESTARTNOINTR:
546 __frame->gr8 = __frame->orig_gr8;
547 __frame->pc -= 4;
548 break;
549
550 case -ERESTART_RESTARTBLOCK:
551 __frame->gr7 = __NR_restart_syscall;
552 __frame->pc -= 4;
553 break;
554 }
555 __frame->syscallno = -1;
556 }
557
558 /* if there's no signal to deliver, we just put the saved sigmask
559 * back */
560 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
561 clear_thread_flag(TIF_RESTORE_SIGMASK);
562 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
563 }
564
565 } /* end do_signal() */
566
567 /*****************************************************************************/
568 /*
569 * notification of userspace execution resumption
570 * - triggered by the TIF_WORK_MASK flags
571 */
do_notify_resume(__u32 thread_info_flags)572 asmlinkage void do_notify_resume(__u32 thread_info_flags)
573 {
574 /* pending single-step? */
575 if (thread_info_flags & _TIF_SINGLESTEP)
576 clear_thread_flag(TIF_SINGLESTEP);
577
578 /* deal with pending signal delivery */
579 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
580 do_signal();
581
582 /* deal with notification on about to resume userspace execution */
583 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
584 clear_thread_flag(TIF_NOTIFY_RESUME);
585 tracehook_notify_resume(__frame);
586 if (current->replacement_session_keyring)
587 key_replace_session_keyring();
588 }
589
590 } /* end do_notify_resume() */
591