Merge branch 'master' of git://oak/home/sfr/kernels/iseries/work
[linux-2.6] / arch / sh / kernel / signal.c
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         return do_sigaltstack(uss, uoss, regs.regs[15]);
93 }
94
95
96 /*
97  * Do a signal return; undo the signal stack.
98  */
99
100 #define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */
101 #define TRAP16   0xc310                 /* Syscall w/no args (NR in R3) */
102 #define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */
103
104 struct sigframe
105 {
106         struct sigcontext sc;
107         unsigned long extramask[_NSIG_WORDS-1];
108         u16 retcode[8];
109 };
110
111 struct rt_sigframe
112 {
113         struct siginfo info;
114         struct ucontext uc;
115         u16 retcode[8];
116 };
117
118 #ifdef CONFIG_SH_FPU
119 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
120 {
121         struct task_struct *tsk = current;
122
123         if (!(cpu_data->flags & CPU_HAS_FPU))
124                 return 0;
125
126         set_used_math();
127         return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],
128                                 sizeof(long)*(16*2+2));
129 }
130
131 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
132                                       struct pt_regs *regs)
133 {
134         struct task_struct *tsk = current;
135
136         if (!(cpu_data->flags & CPU_HAS_FPU))
137                 return 0;
138
139         if (!used_math()) {
140                 __put_user(0, &sc->sc_ownedfp);
141                 return 0;
142         }
143
144         __put_user(1, &sc->sc_ownedfp);
145
146         /* This will cause a "finit" to be triggered by the next
147            attempted FPU operation by the 'current' process.
148            */
149         clear_used_math();
150
151         unlazy_fpu(tsk, regs);
152         return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,
153                               sizeof(long)*(16*2+2));
154 }
155 #endif /* CONFIG_SH_FPU */
156
157 static int
158 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
159 {
160         unsigned int err = 0;
161
162 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
163                         COPY(regs[1]);
164         COPY(regs[2]);  COPY(regs[3]);
165         COPY(regs[4]);  COPY(regs[5]);
166         COPY(regs[6]);  COPY(regs[7]);
167         COPY(regs[8]);  COPY(regs[9]);
168         COPY(regs[10]); COPY(regs[11]);
169         COPY(regs[12]); COPY(regs[13]);
170         COPY(regs[14]); COPY(regs[15]);
171         COPY(gbr);      COPY(mach);
172         COPY(macl);     COPY(pr);
173         COPY(sr);       COPY(pc);
174 #undef COPY
175
176 #ifdef CONFIG_SH_FPU
177         if (cpu_data->flags & CPU_HAS_FPU) {
178                 int owned_fp;
179                 struct task_struct *tsk = current;
180
181                 regs->sr |= SR_FD; /* Release FPU */
182                 clear_fpu(tsk, regs);
183                 clear_used_math();
184                 __get_user (owned_fp, &sc->sc_ownedfp);
185                 if (owned_fp)
186                         err |= restore_sigcontext_fpu(sc);
187         }
188 #endif
189
190         regs->tra = -1;         /* disable syscall checks */
191         err |= __get_user(*r0_p, &sc->sc_regs[0]);
192         return err;
193 }
194
195 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
196                              unsigned long r6, unsigned long r7,
197                              struct pt_regs regs)
198 {
199         struct sigframe __user *frame = (struct sigframe __user *)regs.regs[15];
200         sigset_t set;
201         int r0;
202
203         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
204                 goto badframe;
205
206         if (__get_user(set.sig[0], &frame->sc.oldmask)
207             || (_NSIG_WORDS > 1
208                 && __copy_from_user(&set.sig[1], &frame->extramask,
209                                     sizeof(frame->extramask))))
210                 goto badframe;
211
212         sigdelsetmask(&set, ~_BLOCKABLE);
213
214         spin_lock_irq(&current->sighand->siglock);
215         current->blocked = set;
216         recalc_sigpending();
217         spin_unlock_irq(&current->sighand->siglock);
218
219         if (restore_sigcontext(&regs, &frame->sc, &r0))
220                 goto badframe;
221         return r0;
222
223 badframe:
224         force_sig(SIGSEGV, current);
225         return 0;
226 }
227
228 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
229                                 unsigned long r6, unsigned long r7,
230                                 struct pt_regs regs)
231 {
232         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs.regs[15];
233         sigset_t set;
234         stack_t st;
235         int r0;
236
237         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
238                 goto badframe;
239
240         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
241                 goto badframe;
242
243         sigdelsetmask(&set, ~_BLOCKABLE);
244         spin_lock_irq(&current->sighand->siglock);
245         current->blocked = set;
246         recalc_sigpending();
247         spin_unlock_irq(&current->sighand->siglock);
248
249         if (restore_sigcontext(&regs, &frame->uc.uc_mcontext, &r0))
250                 goto badframe;
251
252         if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
253                 goto badframe;
254         /* It is more difficult to avoid calling this function than to
255            call it and ignore errors.  */
256         do_sigaltstack(&st, NULL, regs.regs[15]);
257
258         return r0;
259
260 badframe:
261         force_sig(SIGSEGV, current);
262         return 0;
263 }       
264
265 /*
266  * Set up a signal frame.
267  */
268
269 static int
270 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
271                  unsigned long mask)
272 {
273         int err = 0;
274
275 #define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)
276         COPY(regs[0]);  COPY(regs[1]);
277         COPY(regs[2]);  COPY(regs[3]);
278         COPY(regs[4]);  COPY(regs[5]);
279         COPY(regs[6]);  COPY(regs[7]);
280         COPY(regs[8]);  COPY(regs[9]);
281         COPY(regs[10]); COPY(regs[11]);
282         COPY(regs[12]); COPY(regs[13]);
283         COPY(regs[14]); COPY(regs[15]);
284         COPY(gbr);      COPY(mach);
285         COPY(macl);     COPY(pr);
286         COPY(sr);       COPY(pc);
287 #undef COPY
288
289 #ifdef CONFIG_SH_FPU
290         err |= save_sigcontext_fpu(sc, regs);
291 #endif
292
293         /* non-iBCS2 extensions.. */
294         err |= __put_user(mask, &sc->oldmask);
295
296         return err;
297 }
298
299 /*
300  * Determine which stack to use..
301  */
302 static inline void __user *
303 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
304 {
305         if (ka->sa.sa_flags & SA_ONSTACK) {
306                 if (sas_ss_flags(sp) == 0)
307                         sp = current->sas_ss_sp + current->sas_ss_size;
308         }
309
310         return (void __user *)((sp - frame_size) & -8ul);
311 }
312
313 /* These symbols are defined with the addresses in the vsyscall page.
314    See vsyscall-trapa.S.  */
315 extern void __user __kernel_sigreturn;
316 extern void __user __kernel_rt_sigreturn;
317
318 static int setup_frame(int sig, struct k_sigaction *ka,
319                         sigset_t *set, struct pt_regs *regs)
320 {
321         struct sigframe __user *frame;
322         int err = 0;
323         int signal;
324
325         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
326
327         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
328                 goto give_sigsegv;
329
330         signal = current_thread_info()->exec_domain
331                 && current_thread_info()->exec_domain->signal_invmap
332                 && sig < 32
333                 ? current_thread_info()->exec_domain->signal_invmap[sig]
334                 : sig;
335
336         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
337
338         if (_NSIG_WORDS > 1)
339                 err |= __copy_to_user(frame->extramask, &set->sig[1],
340                                       sizeof(frame->extramask));
341
342         /* Set up to return from userspace.  If provided, use a stub
343            already in userspace.  */
344         if (ka->sa.sa_flags & SA_RESTORER) {
345                 regs->pr = (unsigned long) ka->sa.sa_restorer;
346 #ifdef CONFIG_VSYSCALL
347         } else if (likely(current->mm->context.vdso)) {
348                 regs->pr = VDSO_SYM(&__kernel_sigreturn);
349 #endif
350         } else {
351                 /* Generate return code (system call to sigreturn) */
352                 err |= __put_user(MOVW(7), &frame->retcode[0]);
353                 err |= __put_user(TRAP16, &frame->retcode[1]);
354                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
355                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
356                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
357                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
358                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
359                 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
360                 regs->pr = (unsigned long) frame->retcode;
361         }
362
363         if (err)
364                 goto give_sigsegv;
365
366         /* Set up registers for signal handler */
367         regs->regs[15] = (unsigned long) frame;
368         regs->regs[4] = signal; /* Arg for signal handler */
369         regs->regs[5] = 0;
370         regs->regs[6] = (unsigned long) &frame->sc;
371         regs->pc = (unsigned long) ka->sa.sa_handler;
372
373         set_fs(USER_DS);
374
375         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
376                  current->comm, current->pid, frame, regs->pc, regs->pr);
377
378         flush_cache_sigtramp(regs->pr);
379
380         if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
381                 flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
382
383         return 0;
384
385 give_sigsegv:
386         force_sigsegv(sig, current);
387         return -EFAULT;
388 }
389
390 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
391                            sigset_t *set, struct pt_regs *regs)
392 {
393         struct rt_sigframe __user *frame;
394         int err = 0;
395         int signal;
396
397         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
398
399         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
400                 goto give_sigsegv;
401
402         signal = current_thread_info()->exec_domain
403                 && current_thread_info()->exec_domain->signal_invmap
404                 && sig < 32
405                 ? current_thread_info()->exec_domain->signal_invmap[sig]
406                 : sig;
407
408         err |= copy_siginfo_to_user(&frame->info, info);
409
410         /* Create the ucontext.  */
411         err |= __put_user(0, &frame->uc.uc_flags);
412         err |= __put_user(0, &frame->uc.uc_link);
413         err |= __put_user((void *)current->sas_ss_sp,
414                           &frame->uc.uc_stack.ss_sp);
415         err |= __put_user(sas_ss_flags(regs->regs[15]),
416                           &frame->uc.uc_stack.ss_flags);
417         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
418         err |= setup_sigcontext(&frame->uc.uc_mcontext,
419                                 regs, set->sig[0]);
420         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
421
422         /* Set up to return from userspace.  If provided, use a stub
423            already in userspace.  */
424         if (ka->sa.sa_flags & SA_RESTORER) {
425                 regs->pr = (unsigned long) ka->sa.sa_restorer;
426 #ifdef CONFIG_VSYSCALL
427         } else if (likely(current->mm->context.vdso)) {
428                 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
429 #endif
430         } else {
431                 /* Generate return code (system call to rt_sigreturn) */
432                 err |= __put_user(MOVW(7), &frame->retcode[0]);
433                 err |= __put_user(TRAP16, &frame->retcode[1]);
434                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
435                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
436                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
437                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
438                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
439                 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
440                 regs->pr = (unsigned long) frame->retcode;
441         }
442
443         if (err)
444                 goto give_sigsegv;
445
446         /* Set up registers for signal handler */
447         regs->regs[15] = (unsigned long) frame;
448         regs->regs[4] = signal; /* Arg for signal handler */
449         regs->regs[5] = (unsigned long) &frame->info;
450         regs->regs[6] = (unsigned long) &frame->uc;
451         regs->pc = (unsigned long) ka->sa.sa_handler;
452
453         set_fs(USER_DS);
454
455         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
456                  current->comm, current->pid, frame, regs->pc, regs->pr);
457
458         flush_cache_sigtramp(regs->pr);
459
460         if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
461                 flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
462
463         return 0;
464
465 give_sigsegv:
466         force_sigsegv(sig, current);
467         return -EFAULT;
468 }
469
470 /*
471  * OK, we're invoking a handler
472  */
473
474 static int
475 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
476               sigset_t *oldset, struct pt_regs *regs)
477 {
478         int ret;
479
480         /* Are we from a system call? */
481         if (regs->tra >= 0) {
482                 /* If so, check system call restarting.. */
483                 switch (regs->regs[0]) {
484                         case -ERESTARTNOHAND:
485                                 regs->regs[0] = -EINTR;
486                                 break;
487
488                         case -ERESTARTSYS:
489                                 if (!(ka->sa.sa_flags & SA_RESTART)) {
490                                         regs->regs[0] = -EINTR;
491                                         break;
492                                 }
493                         /* fallthrough */
494                         case -ERESTARTNOINTR:
495                                 regs->pc -= 2;
496                 }
497         } else {
498                 /* gUSA handling */
499 #ifdef CONFIG_PREEMPT
500                 unsigned long flags;
501
502                 local_irq_save(flags);
503 #endif
504                 if (regs->regs[15] >= 0xc0000000) {
505                         int offset = (int)regs->regs[15];
506
507                         /* Reset stack pointer: clear critical region mark */
508                         regs->regs[15] = regs->regs[1];
509                         if (regs->pc < regs->regs[0])
510                                 /* Go to rewind point #1 */
511                                 regs->pc = regs->regs[0] + offset - 2;
512                 }
513 #ifdef CONFIG_PREEMPT
514                 local_irq_restore(flags);
515 #endif
516         }
517
518         /* Set up the stack frame */
519         if (ka->sa.sa_flags & SA_SIGINFO)
520                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
521         else
522                 ret = setup_frame(sig, ka, oldset, regs);
523
524         if (ka->sa.sa_flags & SA_ONESHOT)
525                 ka->sa.sa_handler = SIG_DFL;
526
527         if (ret == 0) {
528                 spin_lock_irq(&current->sighand->siglock);
529                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
530                 if (!(ka->sa.sa_flags & SA_NODEFER))
531                         sigaddset(&current->blocked,sig);
532                 recalc_sigpending();
533                 spin_unlock_irq(&current->sighand->siglock);
534         }
535
536         return ret;
537 }
538
539 /*
540  * Note that 'init' is a special process: it doesn't get signals it doesn't
541  * want to handle. Thus you cannot kill init even with a SIGKILL even by
542  * mistake.
543  *
544  * Note that we go through the signals twice: once to check the signals that
545  * the kernel can handle, and then we build all the user-level signal handling
546  * stack-frames in one go after that.
547  */
548 static void do_signal(struct pt_regs *regs, unsigned int save_r0)
549 {
550         siginfo_t info;
551         int signr;
552         struct k_sigaction ka;
553         sigset_t *oldset;
554
555         /*
556          * We want the common case to go fast, which
557          * is why we may in certain cases get here from
558          * kernel mode. Just return without doing anything
559          * if so.
560          */
561         if (!user_mode(regs))
562                 return;
563
564         if (try_to_freeze())
565                 goto no_signal;
566
567         if (test_thread_flag(TIF_RESTORE_SIGMASK))
568                 oldset = &current->saved_sigmask;
569         else
570                 oldset = &current->blocked;
571
572         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
573         if (signr > 0) {
574                 /* Whee!  Actually deliver the signal.  */
575                 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
576                         /* a signal was successfully delivered; the saved
577                          * sigmask will have been stored in the signal frame,
578                          * and will be restored by sigreturn, so we can simply
579                          * clear the TIF_RESTORE_SIGMASK flag */
580                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
581                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
582                 }
583         }
584
585  no_signal:
586         /* Did we come from a system call? */
587         if (regs->tra >= 0) {
588                 /* Restart the system call - no handlers present */
589                 if (regs->regs[0] == -ERESTARTNOHAND ||
590                     regs->regs[0] == -ERESTARTSYS ||
591                     regs->regs[0] == -ERESTARTNOINTR) {
592                         regs->regs[0] = save_r0;
593                         regs->pc -= 2;
594                 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
595                         regs->pc -= 2;
596                         regs->regs[3] = __NR_restart_syscall;
597                 }
598         }
599
600         /* if there's no signal to deliver, we just put the saved sigmask
601          * back */
602         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
603                 clear_thread_flag(TIF_RESTORE_SIGMASK);
604                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
605         }
606 }
607
608 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
609                                  __u32 thread_info_flags)
610 {
611         /* deal with pending signal delivery */
612         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
613                 do_signal(regs, save_r0);
614 }