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CRISv10: remove redundant tests on unsigned
[linux-2.6/mini2440.git] / arch / microblaze / kernel / signal.c
blob40d36931e363eccefd2857383e60fb162f6bf492
1 /*
2 * Signal handling
3 *
4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2008-2009 PetaLogix
6 * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
7 * Copyright (C) 2001 NEC Corporation
8 * Copyright (C) 2001 Miles Bader <miles@gnu.org>
9 * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
10 * Copyright (C) 1991,1992 Linus Torvalds
11 *
12 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
13 *
14 * This file was was derived from the sh version, arch/sh/kernel/signal.c
15 *
16 * This file is subject to the terms and conditions of the GNU General
17 * Public License. See the file COPYING in the main directory of this
18 * archive for more details.
19 */
20
21 #include <linux/sched.h>
22 #include <linux/mm.h>
23 #include <linux/smp.h>
24 #include <linux/smp_lock.h>
25 #include <linux/kernel.h>
26 #include <linux/signal.h>
27 #include <linux/errno.h>
28 #include <linux/wait.h>
29 #include <linux/ptrace.h>
30 #include <linux/unistd.h>
31 #include <linux/stddef.h>
32 #include <linux/personality.h>
33 #include <linux/percpu.h>
34 #include <linux/linkage.h>
35 #include <asm/entry.h>
36 #include <asm/ucontext.h>
37 #include <linux/uaccess.h>
38 #include <asm/pgtable.h>
39 #include <asm/pgalloc.h>
40 #include <linux/syscalls.h>
41 #include <asm/cacheflush.h>
42 #include <asm/syscalls.h>
43
44 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
45
46 asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_sycall);
47
48 /*
49 * Atomically swap in the new signal mask, and wait for a signal.
50 */
51 asmlinkage int
52 sys_sigsuspend(old_sigset_t mask, struct pt_regs *regs)
53 {
54 sigset_t saveset;
55
56 mask &= _BLOCKABLE;
57 spin_lock_irq(&current->sighand->siglock);
58 saveset = current->blocked;
59 siginitset(&current->blocked, mask);
60 recalc_sigpending();
61 spin_unlock_irq(&current->sighand->siglock);
62
63 regs->r3 = -EINTR;
64 while (1) {
65 current->state = TASK_INTERRUPTIBLE;
66 schedule();
67 if (do_signal(regs, &saveset, 1))
68 return -EINTR;
69 }
70 }
71
72 asmlinkage int
73 sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize,
74 struct pt_regs *regs)
75 {
76 sigset_t saveset, newset;
77
78 /* XXX: Don't preclude handling different sized sigset_t's. */
79 if (sigsetsize != sizeof(sigset_t))
80 return -EINVAL;
81
82 if (copy_from_user(&newset, unewset, sizeof(newset)))
83 return -EFAULT;
84 sigdelsetmask(&newset, ~_BLOCKABLE);
85 spin_lock_irq(&current->sighand->siglock);
86 saveset = current->blocked;
87 current->blocked = newset;
88 recalc_sigpending();
89 spin_unlock_irq(&current->sighand->siglock);
90
91 regs->r3 = -EINTR;
92 while (1) {
93 current->state = TASK_INTERRUPTIBLE;
94 schedule();
95 if (do_signal(regs, &saveset, 1))
96 return -EINTR;
97 }
98 }
99
100 asmlinkage int
101 sys_sigaction(int sig, const struct old_sigaction *act,
102 struct old_sigaction *oact)
103 {
104 struct k_sigaction new_ka, old_ka;
105 int ret;
106
107 if (act) {
108 old_sigset_t mask;
109 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
110 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
111 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
112 return -EFAULT;
113 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
114 __get_user(mask, &act->sa_mask);
115 siginitset(&new_ka.sa.sa_mask, mask);
116 }
117
118 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
119
120 if (!ret && oact) {
121 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
122 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
123 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
124 return -EFAULT;
125 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
126 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
127 }
128
129 return ret;
130 }
131
132 asmlinkage int
133 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
134 struct pt_regs *regs)
135 {
136 return do_sigaltstack(uss, uoss, regs->r1);
137 }
138
139 /*
140 * Do a signal return; undo the signal stack.
141 */
142
143 struct sigframe {
144 struct sigcontext sc;
145 unsigned long extramask[_NSIG_WORDS-1];
146 unsigned long tramp[2]; /* signal trampoline */
147 };
148
149 struct rt_sigframe {
150 struct siginfo info;
151 struct ucontext uc;
152 unsigned long tramp[2]; /* signal trampoline */
153 };
154
155 static int
156 restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *rval_p)
157 {
158 unsigned int err = 0;
159
160 #define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); }
161 COPY(r0);
162 COPY(r1);
163 COPY(r2); COPY(r3); COPY(r4); COPY(r5);
164 COPY(r6); COPY(r7); COPY(r8); COPY(r9);
165 COPY(r10); COPY(r11); COPY(r12); COPY(r13);
166 COPY(r14); COPY(r15); COPY(r16); COPY(r17);
167 COPY(r18); COPY(r19); COPY(r20); COPY(r21);
168 COPY(r22); COPY(r23); COPY(r24); COPY(r25);
169 COPY(r26); COPY(r27); COPY(r28); COPY(r29);
170 COPY(r30); COPY(r31);
171 COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
172 #undef COPY
173
174 *rval_p = regs->r3;
175
176 return err;
177 }
178
179 asmlinkage int sys_sigreturn(struct pt_regs *regs)
180 {
181 struct sigframe *frame =
182 (struct sigframe *)(regs->r1 + STATE_SAVE_ARG_SPACE);
183
184 sigset_t set;
185 int rval;
186
187 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
188 goto badframe;
189
190 if (__get_user(set.sig[0], &frame->sc.oldmask)
191 || (_NSIG_WORDS > 1
192 && __copy_from_user(&set.sig[1], &frame->extramask,
193 sizeof(frame->extramask))))
194 goto badframe;
195
196 sigdelsetmask(&set, ~_BLOCKABLE);
197
198 spin_lock_irq(&current->sighand->siglock);
199 current->blocked = set;
200 recalc_sigpending();
201 spin_unlock_irq(&current->sighand->siglock);
202
203 if (restore_sigcontext(regs, &frame->sc, &rval))
204 goto badframe;
205 return rval;
206
207 badframe:
208 force_sig(SIGSEGV, current);
209 return 0;
210 }
211
212 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
213 {
214 struct rt_sigframe *frame =
215 (struct rt_sigframe *)(regs->r1 + STATE_SAVE_ARG_SPACE);
216
217 sigset_t set;
218 stack_t st;
219 int rval;
220
221 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
222 goto badframe;
223
224 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
225 goto badframe;
226
227 sigdelsetmask(&set, ~_BLOCKABLE);
228 spin_lock_irq(&current->sighand->siglock);
229 current->blocked = set;
230 recalc_sigpending();
231 spin_unlock_irq(&current->sighand->siglock);
232
233 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
234 goto badframe;
235
236 if (__copy_from_user((void *)&st, &frame->uc.uc_stack, sizeof(st)))
237 goto badframe;
238 /* It is more difficult to avoid calling this function than to
239 call it and ignore errors. */
240 do_sigaltstack(&st, NULL, regs->r1);
241
242 return rval;
243
244 badframe:
245 force_sig(SIGSEGV, current);
246 return 0;
247 }
248
249 /*
250 * Set up a signal frame.
251 */
252
253 static int
254 setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
255 unsigned long mask)
256 {
257 int err = 0;
258
259 #define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); }
260 COPY(r0);
261 COPY(r1);
262 COPY(r2); COPY(r3); COPY(r4); COPY(r5);
263 COPY(r6); COPY(r7); COPY(r8); COPY(r9);
264 COPY(r10); COPY(r11); COPY(r12); COPY(r13);
265 COPY(r14); COPY(r15); COPY(r16); COPY(r17);
266 COPY(r18); COPY(r19); COPY(r20); COPY(r21);
267 COPY(r22); COPY(r23); COPY(r24); COPY(r25);
268 COPY(r26); COPY(r27); COPY(r28); COPY(r29);
269 COPY(r30); COPY(r31);
270 COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
271 #undef COPY
272
273 err |= __put_user(mask, &sc->oldmask);
274
275 return err;
276 }
277
278 /*
279 * Determine which stack to use..
280 */
281 static inline void *
282 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
283 {
284 /* Default to using normal stack */
285 unsigned long sp = regs->r1;
286
287 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp))
288 sp = current->sas_ss_sp + current->sas_ss_size;
289
290 return (void *)((sp - frame_size) & -8UL);
291 }
292
293 static void setup_frame(int sig, struct k_sigaction *ka,
294 sigset_t *set, struct pt_regs *regs)
295 {
296 struct sigframe *frame;
297 int err = 0;
298 int signal;
299
300 frame = get_sigframe(ka, regs, sizeof(*frame));
301
302 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
303 goto give_sigsegv;
304
305 signal = current_thread_info()->exec_domain
306 && current_thread_info()->exec_domain->signal_invmap
307 && sig < 32
308 ? current_thread_info()->exec_domain->signal_invmap[sig]
309 : sig;
310
311 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
312
313 if (_NSIG_WORDS > 1) {
314 err |= __copy_to_user(frame->extramask, &set->sig[1],
315 sizeof(frame->extramask));
316 }
317
318 /* Set up to return from userspace. If provided, use a stub
319 already in userspace. */
320 /* minus 8 is offset to cater for "rtsd r15,8" offset */
321 if (ka->sa.sa_flags & SA_RESTORER) {
322 regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8;
323 } else {
324 /* Note, these encodings are _big endian_! */
325
326 /* addi r12, r0, __NR_sigreturn */
327 err |= __put_user(0x31800000 | __NR_sigreturn ,
328 frame->tramp + 0);
329 /* brki r14, 0x8 */
330 err |= __put_user(0xb9cc0008, frame->tramp + 1);
331
332 /* Return from sighandler will jump to the tramp.
333 Negative 8 offset because return is rtsd r15, 8 */
334 regs->r15 = ((unsigned long)frame->tramp)-8;
335
336 __invalidate_cache_sigtramp((unsigned long)frame->tramp);
337 }
338
339 if (err)
340 goto give_sigsegv;
341
342 /* Set up registers for signal handler */
343 regs->r1 = (unsigned long) frame - STATE_SAVE_ARG_SPACE;
344
345 /* Signal handler args: */
346 regs->r5 = signal; /* Arg 0: signum */
347 regs->r6 = (unsigned long) &frame->sc; /* arg 1: sigcontext */
348
349 /* Offset of 4 to handle microblaze rtid r14, 0 */
350 regs->pc = (unsigned long)ka->sa.sa_handler;
351
352 set_fs(USER_DS);
353
354 #ifdef DEBUG_SIG
355 printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
356 current->comm, current->pid, frame, regs->pc);
357 #endif
358
359 return;
360
361 give_sigsegv:
362 if (sig == SIGSEGV)
363 ka->sa.sa_handler = SIG_DFL;
364 force_sig(SIGSEGV, current);
365 }
366
367 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
368 sigset_t *set, struct pt_regs *regs)
369 {
370 struct rt_sigframe *frame;
371 int err = 0;
372 int signal;
373
374 frame = get_sigframe(ka, regs, sizeof(*frame));
375
376 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
377 goto give_sigsegv;
378
379 signal = current_thread_info()->exec_domain
380 && current_thread_info()->exec_domain->signal_invmap
381 && sig < 32
382 ? current_thread_info()->exec_domain->signal_invmap[sig]
383 : sig;
384
385 err |= copy_siginfo_to_user(&frame->info, info);
386
387 /* Create the ucontext. */
388 err |= __put_user(0, &frame->uc.uc_flags);
389 err |= __put_user(0, &frame->uc.uc_link);
390 err |= __put_user((void *)current->sas_ss_sp,
391 &frame->uc.uc_stack.ss_sp);
392 err |= __put_user(sas_ss_flags(regs->r1),
393 &frame->uc.uc_stack.ss_flags);
394 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
395 err |= setup_sigcontext(&frame->uc.uc_mcontext,
396 regs, set->sig[0]);
397 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
398
399 /* Set up to return from userspace. If provided, use a stub
400 already in userspace. */
401 /* minus 8 is offset to cater for "rtsd r15,8" */
402 if (ka->sa.sa_flags & SA_RESTORER) {
403 regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8;
404 } else {
405 /* addi r12, r0, __NR_sigreturn */
406 err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
407 frame->tramp + 0);
408 /* brki r14, 0x8 */
409 err |= __put_user(0xb9cc0008, frame->tramp + 1);
410
411 /* Return from sighandler will jump to the tramp.
412 Negative 8 offset because return is rtsd r15, 8 */
413 regs->r15 = ((unsigned long)frame->tramp)-8;
414
415 __invalidate_cache_sigtramp((unsigned long)frame->tramp);
416 }
417
418 if (err)
419 goto give_sigsegv;
420
421 /* Set up registers for signal handler */
422 regs->r1 = (unsigned long) frame - STATE_SAVE_ARG_SPACE;
423
424 /* Signal handler args: */
425 regs->r5 = signal; /* arg 0: signum */
426 regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
427 regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
428 /* Offset to handle microblaze rtid r14, 0 */
429 regs->pc = (unsigned long)ka->sa.sa_handler;
430
431 set_fs(USER_DS);
432
433 #ifdef DEBUG_SIG
434 printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
435 current->comm, current->pid, frame, regs->pc);
436 #endif
437
438 return;
439
440 give_sigsegv:
441 if (sig == SIGSEGV)
442 ka->sa.sa_handler = SIG_DFL;
443 force_sig(SIGSEGV, current);
444 }
445
446 /* Handle restarting system calls */
447 static inline void
448 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
449 {
450 switch (regs->r3) {
451 case -ERESTART_RESTARTBLOCK:
452 case -ERESTARTNOHAND:
453 if (!has_handler)
454 goto do_restart;
455 regs->r3 = -EINTR;
456 break;
457 case -ERESTARTSYS:
458 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
459 regs->r3 = -EINTR;
460 break;
461 }
462 /* fallthrough */
463 case -ERESTARTNOINTR:
464 do_restart:
465 /* offset of 4 bytes to re-execute trap (brki) instruction */
466 regs->pc -= 4;
467 break;
468 }
469 }
470
471 /*
472 * OK, we're invoking a handler
473 */
474
475 static void
476 handle_signal(unsigned long sig, struct k_sigaction *ka,
477 siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
478 {
479 /* Set up the stack frame */
480 if (ka->sa.sa_flags & SA_SIGINFO)
481 setup_rt_frame(sig, ka, info, oldset, regs);
482 else
483 setup_frame(sig, ka, oldset, regs);
484
485 if (ka->sa.sa_flags & SA_ONESHOT)
486 ka->sa.sa_handler = SIG_DFL;
487
488 if (!(ka->sa.sa_flags & SA_NODEFER)) {
489 spin_lock_irq(&current->sighand->siglock);
490 sigorsets(&current->blocked,
491 &current->blocked, &ka->sa.sa_mask);
492 sigaddset(&current->blocked, sig);
493 recalc_sigpending();
494 spin_unlock_irq(&current->sighand->siglock);
495 }
496 }
497
498 /*
499 * Note that 'init' is a special process: it doesn't get signals it doesn't
500 * want to handle. Thus you cannot kill init even with a SIGKILL even by
501 * mistake.
502 *
503 * Note that we go through the signals twice: once to check the signals that
504 * the kernel can handle, and then we build all the user-level signal handling
505 * stack-frames in one go after that.
506 */
507 int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall)
508 {
509 siginfo_t info;
510 int signr;
511 struct k_sigaction ka;
512 #ifdef DEBUG_SIG
513 printk(KERN_INFO "do signal: %p %p %d\n", regs, oldset, in_syscall);
514 printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
515 regs->r12, current_thread_info()->flags);
516 #endif
517 /*
518 * We want the common case to go fast, which
519 * is why we may in certain cases get here from
520 * kernel mode. Just return without doing anything
521 * if so.
522 */
523 if (kernel_mode(regs))
524 return 1;
525
526 if (!oldset)
527 oldset = &current->blocked;
528
529 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
530 if (signr > 0) {
531 /* Whee! Actually deliver the signal. */
532 if (in_syscall)
533 handle_restart(regs, &ka, 1);
534 handle_signal(signr, &ka, &info, oldset, regs);
535 return 1;
536 }
537
538 if (in_syscall)
539 handle_restart(regs, NULL, 0);
540
541 /* Did we come from a system call? */
542 return 0;
543 }
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