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/smp_lock.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/stddef.h>
23 #include <linux/tty.h>
24 #include <linux/personality.h>
25 #include <linux/suspend.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 return -EFAULT;
70 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
71 __get_user(mask, &act->sa_mask);
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 return -EFAULT;
82 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
83 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
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, __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 if (is_using_fpu(current))
106 fpu_kill_state(current);
107
108 #define COPY(x) err |= __get_user(regs->x, &sc->x)
109 COPY(d1); COPY(d2); COPY(d3);
110 COPY(a0); COPY(a1); COPY(a2); COPY(a3);
111 COPY(e0); COPY(e1); COPY(e2); COPY(e3);
112 COPY(e4); COPY(e5); COPY(e6); COPY(e7);
113 COPY(lar); COPY(lir);
114 COPY(mdr); COPY(mdrq);
115 COPY(mcvf); COPY(mcrl); COPY(mcrh);
116 COPY(sp); COPY(pc);
117 #undef COPY
118
119 {
120 unsigned int tmpflags;
121 #ifndef CONFIG_MN10300_USING_JTAG
122 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
123 EPSW_T | EPSW_nAR)
124 #else
125 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
126 EPSW_nAR)
127 #endif
128 err |= __get_user(tmpflags, &sc->epsw);
129 regs->epsw = (regs->epsw & ~USER_EPSW) |
130 (tmpflags & USER_EPSW);
131 regs->orig_d0 = -1; /* disable syscall checks */
132 }
133
134 {
135 struct fpucontext *buf;
136 err |= __get_user(buf, &sc->fpucontext);
137 if (buf) {
138 if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
139 goto badframe;
140 err |= fpu_restore_sigcontext(buf);
141 }
142 }
143
144 err |= __get_user(*_d0, &sc->d0);
145 return err;
146
147 badframe:
148 return 1;
149 }
150
151 /*
152 * standard signal return syscall
153 */
sys_sigreturn(void)154 asmlinkage long sys_sigreturn(void)
155 {
156 struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
157 sigset_t set;
158 long d0;
159
160 if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
161 goto badframe;
162 if (__get_user(set.sig[0], &frame->sc.oldmask))
163 goto badframe;
164
165 if (_NSIG_WORDS > 1 &&
166 __copy_from_user(&set.sig[1], &frame->extramask,
167 sizeof(frame->extramask)))
168 goto badframe;
169
170 sigdelsetmask(&set, ~_BLOCKABLE);
171 spin_lock_irq(¤t->sighand->siglock);
172 current->blocked = set;
173 recalc_sigpending();
174 spin_unlock_irq(¤t->sighand->siglock);
175
176 if (restore_sigcontext(__frame, &frame->sc, &d0))
177 goto badframe;
178
179 return d0;
180
181 badframe:
182 force_sig(SIGSEGV, current);
183 return 0;
184 }
185
186 /*
187 * realtime signal return syscall
188 */
sys_rt_sigreturn(void)189 asmlinkage long sys_rt_sigreturn(void)
190 {
191 struct rt_sigframe __user *frame =
192 (struct rt_sigframe __user *) __frame->sp;
193 sigset_t set;
194 unsigned long d0;
195
196 if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
197 goto badframe;
198 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
199 goto badframe;
200
201 sigdelsetmask(&set, ~_BLOCKABLE);
202 spin_lock_irq(¤t->sighand->siglock);
203 current->blocked = set;
204 recalc_sigpending();
205 spin_unlock_irq(¤t->sighand->siglock);
206
207 if (restore_sigcontext(__frame, &frame->uc.uc_mcontext, &d0))
208 goto badframe;
209
210 if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
211 goto badframe;
212
213 return d0;
214
215 badframe:
216 force_sig(SIGSEGV, current);
217 return 0;
218 }
219
220 /*
221 * store the userspace context into a signal frame
222 */
setup_sigcontext(struct sigcontext __user * sc,struct fpucontext * fpuctx,struct pt_regs * regs,unsigned long mask)223 static int setup_sigcontext(struct sigcontext __user *sc,
224 struct fpucontext *fpuctx,
225 struct pt_regs *regs,
226 unsigned long mask)
227 {
228 int tmp, err = 0;
229
230 #define COPY(x) err |= __put_user(regs->x, &sc->x)
231 COPY(d0); COPY(d1); COPY(d2); COPY(d3);
232 COPY(a0); COPY(a1); COPY(a2); COPY(a3);
233 COPY(e0); COPY(e1); COPY(e2); COPY(e3);
234 COPY(e4); COPY(e5); COPY(e6); COPY(e7);
235 COPY(lar); COPY(lir);
236 COPY(mdr); COPY(mdrq);
237 COPY(mcvf); COPY(mcrl); COPY(mcrh);
238 COPY(sp); COPY(epsw); COPY(pc);
239 #undef COPY
240
241 tmp = fpu_setup_sigcontext(fpuctx);
242 if (tmp < 0)
243 err = 1;
244 else
245 err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);
246
247 /* non-iBCS2 extensions.. */
248 err |= __put_user(mask, &sc->oldmask);
249
250 return err;
251 }
252
253 /*
254 * determine which stack to use..
255 */
get_sigframe(struct k_sigaction * ka,struct pt_regs * regs,size_t frame_size)256 static inline void __user *get_sigframe(struct k_sigaction *ka,
257 struct pt_regs *regs,
258 size_t frame_size)
259 {
260 unsigned long sp;
261
262 /* default to using normal stack */
263 sp = regs->sp;
264
265 /* this is the X/Open sanctioned signal stack switching. */
266 if (ka->sa.sa_flags & SA_ONSTACK) {
267 if (!on_sig_stack(sp))
268 sp = current->sas_ss_sp + current->sas_ss_size;
269 }
270
271 return (void __user *) ((sp - frame_size) & ~7UL);
272 }
273
274 /*
275 * set up a normal signal frame
276 */
setup_frame(int sig,struct k_sigaction * ka,sigset_t * set,struct pt_regs * regs)277 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
278 struct pt_regs *regs)
279 {
280 struct sigframe __user *frame;
281 int rsig;
282
283 frame = get_sigframe(ka, regs, sizeof(*frame));
284
285 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
286 goto give_sigsegv;
287
288 rsig = sig;
289 if (sig < 32 &&
290 current_thread_info()->exec_domain &&
291 current_thread_info()->exec_domain->signal_invmap)
292 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
293
294 if (__put_user(rsig, &frame->sig) < 0 ||
295 __put_user(&frame->sc, &frame->psc) < 0)
296 goto give_sigsegv;
297
298 if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
299 goto give_sigsegv;
300
301 if (_NSIG_WORDS > 1) {
302 if (__copy_to_user(frame->extramask, &set->sig[1],
303 sizeof(frame->extramask)))
304 goto give_sigsegv;
305 }
306
307 /* set up to return from userspace. If provided, use a stub already in
308 * userspace */
309 if (ka->sa.sa_flags & SA_RESTORER) {
310 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
311 goto give_sigsegv;
312 } else {
313 if (__put_user((void (*)(void))frame->retcode,
314 &frame->pretcode))
315 goto give_sigsegv;
316 /* this is mov $,d0; syscall 0 */
317 if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
318 __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
319 __put_user(0x00, (char *)(frame->retcode + 2)) ||
320 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
321 __put_user(0xe0, (char *)(frame->retcode + 4)))
322 goto give_sigsegv;
323 flush_icache_range((unsigned long) frame->retcode,
324 (unsigned long) frame->retcode + 5);
325 }
326
327 /* set up registers for signal handler */
328 regs->sp = (unsigned long) frame;
329 regs->pc = (unsigned long) ka->sa.sa_handler;
330 regs->d0 = sig;
331 regs->d1 = (unsigned long) &frame->sc;
332
333 set_fs(USER_DS);
334
335 /* the tracer may want to single-step inside the handler */
336 if (test_thread_flag(TIF_SINGLESTEP))
337 ptrace_notify(SIGTRAP);
338
339 #if DEBUG_SIG
340 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
341 sig, current->comm, current->pid, frame, regs->pc,
342 frame->pretcode);
343 #endif
344
345 return 0;
346
347 give_sigsegv:
348 force_sig(SIGSEGV, current);
349 return -EFAULT;
350 }
351
352 /*
353 * set up a realtime signal frame
354 */
setup_rt_frame(int sig,struct k_sigaction * ka,siginfo_t * info,sigset_t * set,struct pt_regs * regs)355 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
356 sigset_t *set, struct pt_regs *regs)
357 {
358 struct rt_sigframe __user *frame;
359 int rsig;
360
361 frame = get_sigframe(ka, regs, sizeof(*frame));
362
363 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
364 goto give_sigsegv;
365
366 rsig = sig;
367 if (sig < 32 &&
368 current_thread_info()->exec_domain &&
369 current_thread_info()->exec_domain->signal_invmap)
370 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
371
372 if (__put_user(rsig, &frame->sig) ||
373 __put_user(&frame->info, &frame->pinfo) ||
374 __put_user(&frame->uc, &frame->puc) ||
375 copy_siginfo_to_user(&frame->info, info))
376 goto give_sigsegv;
377
378 /* create the ucontext. */
379 if (__put_user(0, &frame->uc.uc_flags) ||
380 __put_user(0, &frame->uc.uc_link) ||
381 __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
382 __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
383 __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size) ||
384 setup_sigcontext(&frame->uc.uc_mcontext,
385 &frame->fpuctx, regs, set->sig[0]) ||
386 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
387 goto give_sigsegv;
388
389 /* set up to return from userspace. If provided, use a stub already in
390 * userspace */
391 if (ka->sa.sa_flags & SA_RESTORER) {
392 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
393 goto give_sigsegv;
394 } else {
395 if (__put_user((void(*)(void))frame->retcode,
396 &frame->pretcode) ||
397 /* This is mov $,d0; syscall 0 */
398 __put_user(0x2c, (char *)(frame->retcode + 0)) ||
399 __put_user(__NR_rt_sigreturn,
400 (char *)(frame->retcode + 1)) ||
401 __put_user(0x00, (char *)(frame->retcode + 2)) ||
402 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
403 __put_user(0xe0, (char *)(frame->retcode + 4)))
404 goto give_sigsegv;
405
406 flush_icache_range((u_long) frame->retcode,
407 (u_long) frame->retcode + 5);
408 }
409
410 /* Set up registers for signal handler */
411 regs->sp = (unsigned long) frame;
412 regs->pc = (unsigned long) ka->sa.sa_handler;
413 regs->d0 = sig;
414 regs->d1 = (long) &frame->info;
415
416 set_fs(USER_DS);
417
418 /* the tracer may want to single-step inside the handler */
419 if (test_thread_flag(TIF_SINGLESTEP))
420 ptrace_notify(SIGTRAP);
421
422 #if DEBUG_SIG
423 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
424 sig, current->comm, current->pid, frame, regs->pc,
425 frame->pretcode);
426 #endif
427
428 return 0;
429
430 give_sigsegv:
431 force_sig(SIGSEGV, current);
432 return -EFAULT;
433 }
434
435 /*
436 * handle the actual delivery of a signal to userspace
437 */
handle_signal(int sig,siginfo_t * info,struct k_sigaction * ka,sigset_t * oldset,struct pt_regs * regs)438 static int handle_signal(int sig,
439 siginfo_t *info, struct k_sigaction *ka,
440 sigset_t *oldset, struct pt_regs *regs)
441 {
442 int ret;
443
444 /* Are we from a system call? */
445 if (regs->orig_d0 >= 0) {
446 /* If so, check system call restarting.. */
447 switch (regs->d0) {
448 case -ERESTART_RESTARTBLOCK:
449 case -ERESTARTNOHAND:
450 regs->d0 = -EINTR;
451 break;
452
453 case -ERESTARTSYS:
454 if (!(ka->sa.sa_flags & SA_RESTART)) {
455 regs->d0 = -EINTR;
456 break;
457 }
458
459 /* fallthrough */
460 case -ERESTARTNOINTR:
461 regs->d0 = regs->orig_d0;
462 regs->pc -= 2;
463 }
464 }
465
466 /* Set up the stack frame */
467 if (ka->sa.sa_flags & SA_SIGINFO)
468 ret = setup_rt_frame(sig, ka, info, oldset, regs);
469 else
470 ret = setup_frame(sig, ka, oldset, regs);
471
472 if (ret == 0) {
473 spin_lock_irq(¤t->sighand->siglock);
474 sigorsets(¤t->blocked, ¤t->blocked,
475 &ka->sa.sa_mask);
476 if (!(ka->sa.sa_flags & SA_NODEFER))
477 sigaddset(¤t->blocked, sig);
478 recalc_sigpending();
479 spin_unlock_irq(¤t->sighand->siglock);
480 }
481
482 return ret;
483 }
484
485 /*
486 * handle a potential signal
487 */
do_signal(struct pt_regs * regs)488 static void do_signal(struct pt_regs *regs)
489 {
490 struct k_sigaction ka;
491 siginfo_t info;
492 sigset_t *oldset;
493 int signr;
494
495 /* we want the common case to go fast, which is why we may in certain
496 * cases get here from kernel mode */
497 if (!user_mode(regs))
498 return;
499
500 if (test_thread_flag(TIF_RESTORE_SIGMASK))
501 oldset = ¤t->saved_sigmask;
502 else
503 oldset = ¤t->blocked;
504
505 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
506 if (signr > 0) {
507 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
508 /* a signal was successfully delivered; the saved
509 * sigmask will have been stored in the signal frame,
510 * and will be restored by sigreturn, so we can simply
511 * clear the TIF_RESTORE_SIGMASK flag */
512 if (test_thread_flag(TIF_RESTORE_SIGMASK))
513 clear_thread_flag(TIF_RESTORE_SIGMASK);
514 }
515
516 return;
517 }
518
519 /* did we come from a system call? */
520 if (regs->orig_d0 >= 0) {
521 /* restart the system call - no handlers present */
522 switch (regs->d0) {
523 case -ERESTARTNOHAND:
524 case -ERESTARTSYS:
525 case -ERESTARTNOINTR:
526 regs->d0 = regs->orig_d0;
527 regs->pc -= 2;
528 break;
529
530 case -ERESTART_RESTARTBLOCK:
531 regs->d0 = __NR_restart_syscall;
532 regs->pc -= 2;
533 break;
534 }
535 }
536
537 /* if there's no signal to deliver, we just put the saved sigmask
538 * back */
539 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
540 clear_thread_flag(TIF_RESTORE_SIGMASK);
541 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
542 }
543 }
544
545 /*
546 * notification of userspace execution resumption
547 * - triggered by current->work.notify_resume
548 */
do_notify_resume(struct pt_regs * regs,u32 thread_info_flags)549 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
550 {
551 /* Pending single-step? */
552 if (thread_info_flags & _TIF_SINGLESTEP) {
553 #ifndef CONFIG_MN10300_USING_JTAG
554 regs->epsw |= EPSW_T;
555 clear_thread_flag(TIF_SINGLESTEP);
556 #else
557 BUG(); /* no h/w single-step if using JTAG unit */
558 #endif
559 }
560
561 /* deal with pending signal delivery */
562 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
563 do_signal(regs);
564 }
565