1 /* MN10300 Signal handling
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/smp.h>
15 #include <linux/kernel.h>
16 #include <linux/signal.h>
17 #include <linux/errno.h>
18 #include <linux/wait.h>
19 #include <linux/ptrace.h>
20 #include <linux/unistd.h>
21 #include <linux/stddef.h>
22 #include <linux/tty.h>
23 #include <linux/personality.h>
24 #include <linux/suspend.h>
25 #include <linux/tracehook.h>
26 #include <asm/cacheflush.h>
27 #include <asm/ucontext.h>
28 #include <asm/uaccess.h>
29 #include <asm/fpu.h>
30 #include "sigframe.h"
31
32 #define DEBUG_SIG 0
33
34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
35
36 /*
37 * atomically swap in the new signal mask, and wait for a signal.
38 */
sys_sigsuspend(int history0,int history1,old_sigset_t mask)39 asmlinkage long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
40 {
41 mask &= _BLOCKABLE;
42 spin_lock_irq(¤t->sighand->siglock);
43 current->saved_sigmask = current->blocked;
44 siginitset(¤t->blocked, mask);
45 recalc_sigpending();
46 spin_unlock_irq(¤t->sighand->siglock);
47
48 current->state = TASK_INTERRUPTIBLE;
49 schedule();
50 set_thread_flag(TIF_RESTORE_SIGMASK);
51 return -ERESTARTNOHAND;
52 }
53
54 /*
55 * set signal action syscall
56 */
sys_sigaction(int sig,const struct old_sigaction __user * act,struct old_sigaction __user * oact)57 asmlinkage long sys_sigaction(int sig,
58 const struct old_sigaction __user *act,
59 struct old_sigaction __user *oact)
60 {
61 struct k_sigaction new_ka, old_ka;
62 int ret;
63
64 if (act) {
65 old_sigset_t mask;
66 if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
67 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
68 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
69 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
70 __get_user(mask, &act->sa_mask))
71 return -EFAULT;
72 siginitset(&new_ka.sa.sa_mask, mask);
73 }
74
75 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
76
77 if (!ret && oact) {
78 if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
79 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
80 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
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 return -EFAULT;
84 }
85
86 return ret;
87 }
88
89 /*
90 * set alternate signal stack syscall
91 */
sys_sigaltstack(const stack_t __user * uss,stack_t * uoss)92 asmlinkage long sys_sigaltstack(const stack_t __user *uss, stack_t *uoss)
93 {
94 return do_sigaltstack(uss, uoss, current_frame()->sp);
95 }
96
97 /*
98 * do a signal return; undo the signal stack.
99 */
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc,long * _d0)100 static int restore_sigcontext(struct pt_regs *regs,
101 struct sigcontext __user *sc, long *_d0)
102 {
103 unsigned int err = 0;
104
105 /* Always make any pending restarted system calls return -EINTR */
106 current_thread_info()->restart_block.fn = do_no_restart_syscall;
107
108 if (is_using_fpu(current))
109 fpu_kill_state(current);
110
111 #define COPY(x) err |= __get_user(regs->x, &sc->x)
112 COPY(d1); COPY(d2); COPY(d3);
113 COPY(a0); COPY(a1); COPY(a2); COPY(a3);
114 COPY(e0); COPY(e1); COPY(e2); COPY(e3);
115 COPY(e4); COPY(e5); COPY(e6); COPY(e7);
116 COPY(lar); COPY(lir);
117 COPY(mdr); COPY(mdrq);
118 COPY(mcvf); COPY(mcrl); COPY(mcrh);
119 COPY(sp); COPY(pc);
120 #undef COPY
121
122 {
123 unsigned int tmpflags;
124 #ifndef CONFIG_MN10300_USING_JTAG
125 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
126 EPSW_T | EPSW_nAR)
127 #else
128 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
129 EPSW_nAR)
130 #endif
131 err |= __get_user(tmpflags, &sc->epsw);
132 regs->epsw = (regs->epsw & ~USER_EPSW) |
133 (tmpflags & USER_EPSW);
134 regs->orig_d0 = -1; /* disable syscall checks */
135 }
136
137 {
138 struct fpucontext *buf;
139 err |= __get_user(buf, &sc->fpucontext);
140 if (buf) {
141 if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
142 goto badframe;
143 err |= fpu_restore_sigcontext(buf);
144 }
145 }
146
147 err |= __get_user(*_d0, &sc->d0);
148 return err;
149
150 badframe:
151 return 1;
152 }
153
154 /*
155 * standard signal return syscall
156 */
sys_sigreturn(void)157 asmlinkage long sys_sigreturn(void)
158 {
159 struct sigframe __user *frame;
160 sigset_t set;
161 long d0;
162
163 frame = (struct sigframe __user *) current_frame()->sp;
164 if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
165 goto badframe;
166 if (__get_user(set.sig[0], &frame->sc.oldmask))
167 goto badframe;
168
169 if (_NSIG_WORDS > 1 &&
170 __copy_from_user(&set.sig[1], &frame->extramask,
171 sizeof(frame->extramask)))
172 goto badframe;
173
174 sigdelsetmask(&set, ~_BLOCKABLE);
175 spin_lock_irq(¤t->sighand->siglock);
176 current->blocked = set;
177 recalc_sigpending();
178 spin_unlock_irq(¤t->sighand->siglock);
179
180 if (restore_sigcontext(current_frame(), &frame->sc, &d0))
181 goto badframe;
182
183 return d0;
184
185 badframe:
186 force_sig(SIGSEGV, current);
187 return 0;
188 }
189
190 /*
191 * realtime signal return syscall
192 */
sys_rt_sigreturn(void)193 asmlinkage long sys_rt_sigreturn(void)
194 {
195 struct rt_sigframe __user *frame;
196 sigset_t set;
197 long d0;
198
199 frame = (struct rt_sigframe __user *) current_frame()->sp;
200 if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
201 goto badframe;
202 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
203 goto badframe;
204
205 sigdelsetmask(&set, ~_BLOCKABLE);
206 spin_lock_irq(¤t->sighand->siglock);
207 current->blocked = set;
208 recalc_sigpending();
209 spin_unlock_irq(¤t->sighand->siglock);
210
211 if (restore_sigcontext(current_frame(), &frame->uc.uc_mcontext, &d0))
212 goto badframe;
213
214 if (do_sigaltstack(&frame->uc.uc_stack, NULL, current_frame()->sp) ==
215 -EFAULT)
216 goto badframe;
217
218 return d0;
219
220 badframe:
221 force_sig(SIGSEGV, current);
222 return 0;
223 }
224
225 /*
226 * store the userspace context into a signal frame
227 */
setup_sigcontext(struct sigcontext __user * sc,struct fpucontext * fpuctx,struct pt_regs * regs,unsigned long mask)228 static int setup_sigcontext(struct sigcontext __user *sc,
229 struct fpucontext *fpuctx,
230 struct pt_regs *regs,
231 unsigned long mask)
232 {
233 int tmp, err = 0;
234
235 #define COPY(x) err |= __put_user(regs->x, &sc->x)
236 COPY(d0); COPY(d1); COPY(d2); COPY(d3);
237 COPY(a0); COPY(a1); COPY(a2); COPY(a3);
238 COPY(e0); COPY(e1); COPY(e2); COPY(e3);
239 COPY(e4); COPY(e5); COPY(e6); COPY(e7);
240 COPY(lar); COPY(lir);
241 COPY(mdr); COPY(mdrq);
242 COPY(mcvf); COPY(mcrl); COPY(mcrh);
243 COPY(sp); COPY(epsw); COPY(pc);
244 #undef COPY
245
246 tmp = fpu_setup_sigcontext(fpuctx);
247 if (tmp < 0)
248 err = 1;
249 else
250 err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);
251
252 /* non-iBCS2 extensions.. */
253 err |= __put_user(mask, &sc->oldmask);
254
255 return err;
256 }
257
258 /*
259 * determine which stack to use..
260 */
get_sigframe(struct k_sigaction * ka,struct pt_regs * regs,size_t frame_size)261 static inline void __user *get_sigframe(struct k_sigaction *ka,
262 struct pt_regs *regs,
263 size_t frame_size)
264 {
265 unsigned long sp;
266
267 /* default to using normal stack */
268 sp = regs->sp;
269
270 /* this is the X/Open sanctioned signal stack switching. */
271 if (ka->sa.sa_flags & SA_ONSTACK) {
272 if (sas_ss_flags(sp) == 0)
273 sp = current->sas_ss_sp + current->sas_ss_size;
274 }
275
276 return (void __user *) ((sp - frame_size) & ~7UL);
277 }
278
279 /*
280 * set up a normal signal frame
281 */
setup_frame(int sig,struct k_sigaction * ka,sigset_t * set,struct pt_regs * regs)282 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
283 struct pt_regs *regs)
284 {
285 struct sigframe __user *frame;
286 int rsig;
287
288 frame = get_sigframe(ka, regs, sizeof(*frame));
289
290 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
291 goto give_sigsegv;
292
293 rsig = sig;
294 if (sig < 32 &&
295 current_thread_info()->exec_domain &&
296 current_thread_info()->exec_domain->signal_invmap)
297 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
298
299 if (__put_user(rsig, &frame->sig) < 0 ||
300 __put_user(&frame->sc, &frame->psc) < 0)
301 goto give_sigsegv;
302
303 if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
304 goto give_sigsegv;
305
306 if (_NSIG_WORDS > 1) {
307 if (__copy_to_user(frame->extramask, &set->sig[1],
308 sizeof(frame->extramask)))
309 goto give_sigsegv;
310 }
311
312 /* set up to return from userspace. If provided, use a stub already in
313 * userspace */
314 if (ka->sa.sa_flags & SA_RESTORER) {
315 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
316 goto give_sigsegv;
317 } else {
318 if (__put_user((void (*)(void))frame->retcode,
319 &frame->pretcode))
320 goto give_sigsegv;
321 /* this is mov $,d0; syscall 0 */
322 if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
323 __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
324 __put_user(0x00, (char *)(frame->retcode + 2)) ||
325 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
326 __put_user(0xe0, (char *)(frame->retcode + 4)))
327 goto give_sigsegv;
328 flush_icache_range((unsigned long) frame->retcode,
329 (unsigned long) frame->retcode + 5);
330 }
331
332 /* set up registers for signal handler */
333 regs->sp = (unsigned long) frame;
334 regs->pc = (unsigned long) ka->sa.sa_handler;
335 regs->d0 = sig;
336 regs->d1 = (unsigned long) &frame->sc;
337
338 /* the tracer may want to single-step inside the handler */
339 if (test_thread_flag(TIF_SINGLESTEP))
340 ptrace_notify(SIGTRAP);
341
342 #if DEBUG_SIG
343 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
344 sig, current->comm, current->pid, frame, regs->pc,
345 frame->pretcode);
346 #endif
347
348 return 0;
349
350 give_sigsegv:
351 force_sigsegv(sig, current);
352 return -EFAULT;
353 }
354
355 /*
356 * set up a realtime signal frame
357 */
setup_rt_frame(int sig,struct k_sigaction * ka,siginfo_t * info,sigset_t * set,struct pt_regs * regs)358 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
359 sigset_t *set, struct pt_regs *regs)
360 {
361 struct rt_sigframe __user *frame;
362 int rsig;
363
364 frame = get_sigframe(ka, regs, sizeof(*frame));
365
366 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
367 goto give_sigsegv;
368
369 rsig = sig;
370 if (sig < 32 &&
371 current_thread_info()->exec_domain &&
372 current_thread_info()->exec_domain->signal_invmap)
373 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
374
375 if (__put_user(rsig, &frame->sig) ||
376 __put_user(&frame->info, &frame->pinfo) ||
377 __put_user(&frame->uc, &frame->puc) ||
378 copy_siginfo_to_user(&frame->info, info))
379 goto give_sigsegv;
380
381 /* create the ucontext. */
382 if (__put_user(0, &frame->uc.uc_flags) ||
383 __put_user(0, &frame->uc.uc_link) ||
384 __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
385 __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
386 __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size) ||
387 setup_sigcontext(&frame->uc.uc_mcontext,
388 &frame->fpuctx, regs, set->sig[0]) ||
389 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
390 goto give_sigsegv;
391
392 /* set up to return from userspace. If provided, use a stub already in
393 * userspace */
394 if (ka->sa.sa_flags & SA_RESTORER) {
395 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
396 goto give_sigsegv;
397 } else {
398 if (__put_user((void(*)(void))frame->retcode,
399 &frame->pretcode) ||
400 /* This is mov $,d0; syscall 0 */
401 __put_user(0x2c, (char *)(frame->retcode + 0)) ||
402 __put_user(__NR_rt_sigreturn,
403 (char *)(frame->retcode + 1)) ||
404 __put_user(0x00, (char *)(frame->retcode + 2)) ||
405 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
406 __put_user(0xe0, (char *)(frame->retcode + 4)))
407 goto give_sigsegv;
408
409 flush_icache_range((u_long) frame->retcode,
410 (u_long) frame->retcode + 5);
411 }
412
413 /* Set up registers for signal handler */
414 regs->sp = (unsigned long) frame;
415 regs->pc = (unsigned long) ka->sa.sa_handler;
416 regs->d0 = sig;
417 regs->d1 = (long) &frame->info;
418
419 /* the tracer may want to single-step inside the handler */
420 if (test_thread_flag(TIF_SINGLESTEP))
421 ptrace_notify(SIGTRAP);
422
423 #if DEBUG_SIG
424 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
425 sig, current->comm, current->pid, frame, regs->pc,
426 frame->pretcode);
427 #endif
428
429 return 0;
430
431 give_sigsegv:
432 force_sigsegv(sig, current);
433 return -EFAULT;
434 }
435
stepback(struct pt_regs * regs)436 static inline void stepback(struct pt_regs *regs)
437 {
438 regs->pc -= 2;
439 regs->orig_d0 = -1;
440 }
441
442 /*
443 * handle the actual delivery of a signal to userspace
444 */
handle_signal(int sig,siginfo_t * info,struct k_sigaction * ka,sigset_t * oldset,struct pt_regs * regs)445 static int handle_signal(int sig,
446 siginfo_t *info, struct k_sigaction *ka,
447 sigset_t *oldset, struct pt_regs *regs)
448 {
449 int ret;
450
451 /* Are we from a system call? */
452 if (regs->orig_d0 >= 0) {
453 /* If so, check system call restarting.. */
454 switch (regs->d0) {
455 case -ERESTART_RESTARTBLOCK:
456 case -ERESTARTNOHAND:
457 regs->d0 = -EINTR;
458 break;
459
460 case -ERESTARTSYS:
461 if (!(ka->sa.sa_flags & SA_RESTART)) {
462 regs->d0 = -EINTR;
463 break;
464 }
465
466 /* fallthrough */
467 case -ERESTARTNOINTR:
468 regs->d0 = regs->orig_d0;
469 stepback(regs);
470 }
471 }
472
473 /* Set up the stack frame */
474 if (ka->sa.sa_flags & SA_SIGINFO)
475 ret = setup_rt_frame(sig, ka, info, oldset, regs);
476 else
477 ret = setup_frame(sig, ka, oldset, regs);
478
479 if (ret == 0) {
480 spin_lock_irq(¤t->sighand->siglock);
481 sigorsets(¤t->blocked, ¤t->blocked,
482 &ka->sa.sa_mask);
483 if (!(ka->sa.sa_flags & SA_NODEFER))
484 sigaddset(¤t->blocked, sig);
485 recalc_sigpending();
486 spin_unlock_irq(¤t->sighand->siglock);
487 }
488
489 return ret;
490 }
491
492 /*
493 * handle a potential signal
494 */
do_signal(struct pt_regs * regs)495 static void do_signal(struct pt_regs *regs)
496 {
497 struct k_sigaction ka;
498 siginfo_t info;
499 sigset_t *oldset;
500 int signr;
501
502 /* we want the common case to go fast, which is why we may in certain
503 * cases get here from kernel mode */
504 if (!user_mode(regs))
505 return;
506
507 if (test_thread_flag(TIF_RESTORE_SIGMASK))
508 oldset = ¤t->saved_sigmask;
509 else
510 oldset = ¤t->blocked;
511
512 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
513 if (signr > 0) {
514 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
515 /* a signal was successfully delivered; the saved
516 * sigmask will have been stored in the signal frame,
517 * and will be restored by sigreturn, so we can simply
518 * clear the TIF_RESTORE_SIGMASK flag */
519 if (test_thread_flag(TIF_RESTORE_SIGMASK))
520 clear_thread_flag(TIF_RESTORE_SIGMASK);
521
522 tracehook_signal_handler(signr, &info, &ka, regs,
523 test_thread_flag(TIF_SINGLESTEP));
524 }
525
526 return;
527 }
528
529 /* did we come from a system call? */
530 if (regs->orig_d0 >= 0) {
531 /* restart the system call - no handlers present */
532 switch (regs->d0) {
533 case -ERESTARTNOHAND:
534 case -ERESTARTSYS:
535 case -ERESTARTNOINTR:
536 regs->d0 = regs->orig_d0;
537 stepback(regs);
538 break;
539
540 case -ERESTART_RESTARTBLOCK:
541 regs->d0 = __NR_restart_syscall;
542 stepback(regs);
543 break;
544 }
545 }
546
547 /* if there's no signal to deliver, we just put the saved sigmask
548 * back */
549 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
550 clear_thread_flag(TIF_RESTORE_SIGMASK);
551 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
552 }
553 }
554
555 /*
556 * notification of userspace execution resumption
557 * - triggered by current->work.notify_resume
558 */
do_notify_resume(struct pt_regs * regs,u32 thread_info_flags)559 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
560 {
561 /* Pending single-step? */
562 if (thread_info_flags & _TIF_SINGLESTEP) {
563 #ifndef CONFIG_MN10300_USING_JTAG
564 regs->epsw |= EPSW_T;
565 clear_thread_flag(TIF_SINGLESTEP);
566 #else
567 BUG(); /* no h/w single-step if using JTAG unit */
568 #endif
569 }
570
571 /* deal with pending signal delivery */
572 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
573 do_signal(regs);
574
575 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
576 clear_thread_flag(TIF_NOTIFY_RESUME);
577 tracehook_notify_resume(current_frame());
578 if (current->replacement_session_keyring)
579 key_replace_session_keyring();
580 }
581 }
582