Pull video into test branch
[linux-2.6] / arch / s390 / kernel / signal.c
1 /*
2  *  arch/s390/kernel/signal.c
3  *
4  *    Copyright (C) IBM Corp. 1999,2006
5  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
6  *
7  *    Based on Intel version
8  * 
9  *  Copyright (C) 1991, 1992  Linus Torvalds
10  *
11  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
12  */
13
14 #include <linux/sched.h>
15 #include <linux/mm.h>
16 #include <linux/smp.h>
17 #include <linux/smp_lock.h>
18 #include <linux/kernel.h>
19 #include <linux/signal.h>
20 #include <linux/errno.h>
21 #include <linux/wait.h>
22 #include <linux/ptrace.h>
23 #include <linux/unistd.h>
24 #include <linux/stddef.h>
25 #include <linux/tty.h>
26 #include <linux/personality.h>
27 #include <linux/binfmts.h>
28 #include <asm/ucontext.h>
29 #include <asm/uaccess.h>
30 #include <asm/lowcore.h>
31
32 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
33
34
35 typedef struct 
36 {
37         __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
38         struct sigcontext sc;
39         _sigregs sregs;
40         int signo;
41         __u8 retcode[S390_SYSCALL_SIZE];
42 } sigframe;
43
44 typedef struct 
45 {
46         __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
47         __u8 retcode[S390_SYSCALL_SIZE];
48         struct siginfo info;
49         struct ucontext uc;
50 } rt_sigframe;
51
52 /*
53  * Atomically swap in the new signal mask, and wait for a signal.
54  */
55 asmlinkage int
56 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
57 {
58         mask &= _BLOCKABLE;
59         spin_lock_irq(&current->sighand->siglock);
60         current->saved_sigmask = current->blocked;
61         siginitset(&current->blocked, mask);
62         recalc_sigpending();
63         spin_unlock_irq(&current->sighand->siglock);
64
65         current->state = TASK_INTERRUPTIBLE;
66         schedule();
67         set_thread_flag(TIF_RESTORE_SIGMASK);
68
69         return -ERESTARTNOHAND;
70 }
71
72 asmlinkage long
73 sys_sigaction(int sig, const struct old_sigaction __user *act,
74               struct old_sigaction __user *oact)
75 {
76         struct k_sigaction new_ka, old_ka;
77         int ret;
78
79         if (act) {
80                 old_sigset_t mask;
81                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
82                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
83                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
84                     __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
85                     __get_user(mask, &act->sa_mask))
86                         return -EFAULT;
87                 siginitset(&new_ka.sa.sa_mask, mask);
88         }
89
90         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
91
92         if (!ret && oact) {
93                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
94                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
95                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
96                     __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
97                     __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
98                         return -EFAULT;
99         }
100
101         return ret;
102 }
103
104 asmlinkage long
105 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
106                                         struct pt_regs *regs)
107 {
108         return do_sigaltstack(uss, uoss, regs->gprs[15]);
109 }
110
111
112
113 /* Returns non-zero on fault. */
114 static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
115 {
116         _sigregs user_sregs;
117
118         save_access_regs(current->thread.acrs);
119
120         /* Copy a 'clean' PSW mask to the user to avoid leaking
121            information about whether PER is currently on.  */
122         user_sregs.regs.psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
123         user_sregs.regs.psw.addr = regs->psw.addr;
124         memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
125         memcpy(&user_sregs.regs.acrs, current->thread.acrs,
126                sizeof(sregs->regs.acrs));
127         /* 
128          * We have to store the fp registers to current->thread.fp_regs
129          * to merge them with the emulated registers.
130          */
131         save_fp_regs(&current->thread.fp_regs);
132         memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
133                sizeof(s390_fp_regs));
134         return __copy_to_user(sregs, &user_sregs, sizeof(_sigregs));
135 }
136
137 /* Returns positive number on error */
138 static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
139 {
140         int err;
141         _sigregs user_sregs;
142
143         /* Alwys make any pending restarted system call return -EINTR */
144         current_thread_info()->restart_block.fn = do_no_restart_syscall;
145
146         err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
147         if (err)
148                 return err;
149         regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask,
150                                         user_sregs.regs.psw.mask);
151         regs->psw.addr = PSW_ADDR_AMODE | user_sregs.regs.psw.addr;
152         memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
153         memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
154                sizeof(sregs->regs.acrs));
155         restore_access_regs(current->thread.acrs);
156
157         memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
158                sizeof(s390_fp_regs));
159         current->thread.fp_regs.fpc &= FPC_VALID_MASK;
160
161         restore_fp_regs(&current->thread.fp_regs);
162         regs->trap = -1;        /* disable syscall checks */
163         return 0;
164 }
165
166 asmlinkage long sys_sigreturn(struct pt_regs *regs)
167 {
168         sigframe __user *frame = (sigframe __user *)regs->gprs[15];
169         sigset_t set;
170
171         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
172                 goto badframe;
173         if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
174                 goto badframe;
175
176         sigdelsetmask(&set, ~_BLOCKABLE);
177         spin_lock_irq(&current->sighand->siglock);
178         current->blocked = set;
179         recalc_sigpending();
180         spin_unlock_irq(&current->sighand->siglock);
181
182         if (restore_sigregs(regs, &frame->sregs))
183                 goto badframe;
184
185         return regs->gprs[2];
186
187 badframe:
188         force_sig(SIGSEGV, current);
189         return 0;
190 }
191
192 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
193 {
194         rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
195         sigset_t set;
196
197         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
198                 goto badframe;
199         if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
200                 goto badframe;
201
202         sigdelsetmask(&set, ~_BLOCKABLE);
203         spin_lock_irq(&current->sighand->siglock);
204         current->blocked = set;
205         recalc_sigpending();
206         spin_unlock_irq(&current->sighand->siglock);
207
208         if (restore_sigregs(regs, &frame->uc.uc_mcontext))
209                 goto badframe;
210
211         if (do_sigaltstack(&frame->uc.uc_stack, NULL,
212                            regs->gprs[15]) == -EFAULT)
213                 goto badframe;
214         return regs->gprs[2];
215
216 badframe:
217         force_sig(SIGSEGV, current);
218         return 0;
219 }
220
221 /*
222  * Set up a signal frame.
223  */
224
225
226 /*
227  * Determine which stack to use..
228  */
229 static inline void __user *
230 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
231 {
232         unsigned long sp;
233
234         /* Default to using normal stack */
235         sp = regs->gprs[15];
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         /* This is the legacy signal stack switching. */
244         else if (!user_mode(regs) &&
245                  !(ka->sa.sa_flags & SA_RESTORER) &&
246                  ka->sa.sa_restorer) {
247                 sp = (unsigned long) ka->sa.sa_restorer;
248         }
249
250         return (void __user *)((sp - frame_size) & -8ul);
251 }
252
253 static inline int map_signal(int sig)
254 {
255         if (current_thread_info()->exec_domain
256             && current_thread_info()->exec_domain->signal_invmap
257             && sig < 32)
258                 return current_thread_info()->exec_domain->signal_invmap[sig];
259         else
260                 return sig;
261 }
262
263 static int setup_frame(int sig, struct k_sigaction *ka,
264                        sigset_t *set, struct pt_regs * regs)
265 {
266         sigframe __user *frame;
267
268         frame = get_sigframe(ka, regs, sizeof(sigframe));
269         if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
270                 goto give_sigsegv;
271
272         if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
273                 goto give_sigsegv;
274
275         if (save_sigregs(regs, &frame->sregs))
276                 goto give_sigsegv;
277         if (__put_user(&frame->sregs, &frame->sc.sregs))
278                 goto give_sigsegv;
279
280         /* Set up to return from userspace.  If provided, use a stub
281            already in userspace.  */
282         if (ka->sa.sa_flags & SA_RESTORER) {
283                 regs->gprs[14] = (unsigned long)
284                         ka->sa.sa_restorer | PSW_ADDR_AMODE;
285         } else {
286                 regs->gprs[14] = (unsigned long)
287                         frame->retcode | PSW_ADDR_AMODE;
288                 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
289                                (u16 __user *)(frame->retcode)))
290                         goto give_sigsegv;
291         }
292
293         /* Set up backchain. */
294         if (__put_user(regs->gprs[15], (addr_t __user *) frame))
295                 goto give_sigsegv;
296
297         /* Set up registers for signal handler */
298         regs->gprs[15] = (unsigned long) frame;
299         regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
300
301         regs->gprs[2] = map_signal(sig);
302         regs->gprs[3] = (unsigned long) &frame->sc;
303
304         /* We forgot to include these in the sigcontext.
305            To avoid breaking binary compatibility, they are passed as args. */
306         regs->gprs[4] = current->thread.trap_no;
307         regs->gprs[5] = current->thread.prot_addr;
308
309         /* Place signal number on stack to allow backtrace from handler.  */
310         if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
311                 goto give_sigsegv;
312         return 0;
313
314 give_sigsegv:
315         force_sigsegv(sig, current);
316         return -EFAULT;
317 }
318
319 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
320                            sigset_t *set, struct pt_regs * regs)
321 {
322         int err = 0;
323         rt_sigframe __user *frame;
324
325         frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
326         if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
327                 goto give_sigsegv;
328
329         if (copy_siginfo_to_user(&frame->info, info))
330                 goto give_sigsegv;
331
332         /* Create the ucontext.  */
333         err |= __put_user(0, &frame->uc.uc_flags);
334         err |= __put_user(NULL, &frame->uc.uc_link);
335         err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
336         err |= __put_user(sas_ss_flags(regs->gprs[15]),
337                           &frame->uc.uc_stack.ss_flags);
338         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
339         err |= save_sigregs(regs, &frame->uc.uc_mcontext);
340         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
341         if (err)
342                 goto give_sigsegv;
343
344         /* Set up to return from userspace.  If provided, use a stub
345            already in userspace.  */
346         if (ka->sa.sa_flags & SA_RESTORER) {
347                 regs->gprs[14] = (unsigned long)
348                         ka->sa.sa_restorer | PSW_ADDR_AMODE;
349         } else {
350                 regs->gprs[14] = (unsigned long)
351                         frame->retcode | PSW_ADDR_AMODE;
352                 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
353                                (u16 __user *)(frame->retcode)))
354                         goto give_sigsegv;
355         }
356
357         /* Set up backchain. */
358         if (__put_user(regs->gprs[15], (addr_t __user *) frame))
359                 goto give_sigsegv;
360
361         /* Set up registers for signal handler */
362         regs->gprs[15] = (unsigned long) frame;
363         regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
364
365         regs->gprs[2] = map_signal(sig);
366         regs->gprs[3] = (unsigned long) &frame->info;
367         regs->gprs[4] = (unsigned long) &frame->uc;
368         return 0;
369
370 give_sigsegv:
371         force_sigsegv(sig, current);
372         return -EFAULT;
373 }
374
375 /*
376  * OK, we're invoking a handler
377  */     
378
379 static int
380 handle_signal(unsigned long sig, struct k_sigaction *ka,
381               siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
382 {
383         int ret;
384
385         /* Set up the stack frame */
386         if (ka->sa.sa_flags & SA_SIGINFO)
387                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
388         else
389                 ret = setup_frame(sig, ka, oldset, regs);
390
391         if (ret == 0) {
392                 spin_lock_irq(&current->sighand->siglock);
393                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
394                 if (!(ka->sa.sa_flags & SA_NODEFER))
395                         sigaddset(&current->blocked,sig);
396                 recalc_sigpending();
397                 spin_unlock_irq(&current->sighand->siglock);
398         }
399
400         return ret;
401 }
402
403 /*
404  * Note that 'init' is a special process: it doesn't get signals it doesn't
405  * want to handle. Thus you cannot kill init even with a SIGKILL even by
406  * mistake.
407  *
408  * Note that we go through the signals twice: once to check the signals that
409  * the kernel can handle, and then we build all the user-level signal handling
410  * stack-frames in one go after that.
411  */
412 void do_signal(struct pt_regs *regs)
413 {
414         unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
415         siginfo_t info;
416         int signr;
417         struct k_sigaction ka;
418         sigset_t *oldset;
419
420         /*
421          * We want the common case to go fast, which
422          * is why we may in certain cases get here from
423          * kernel mode. Just return without doing anything
424          * if so.
425          */
426         if (!user_mode(regs))
427                 return;
428
429         if (test_thread_flag(TIF_RESTORE_SIGMASK))
430                 oldset = &current->saved_sigmask;
431         else
432                 oldset = &current->blocked;
433
434         /* Are we from a system call? */
435         if (regs->trap == __LC_SVC_OLD_PSW) {
436                 continue_addr = regs->psw.addr;
437                 restart_addr = continue_addr - regs->ilc;
438                 retval = regs->gprs[2];
439
440                 /* Prepare for system call restart.  We do this here so that a
441                    debugger will see the already changed PSW. */
442                 switch (retval) {
443                 case -ERESTARTNOHAND:
444                 case -ERESTARTSYS:
445                 case -ERESTARTNOINTR:
446                         regs->gprs[2] = regs->orig_gpr2;
447                         regs->psw.addr = restart_addr;
448                         break;
449                 case -ERESTART_RESTARTBLOCK:
450                         regs->gprs[2] = -EINTR;
451                 }
452                 regs->trap = -1;        /* Don't deal with this again. */
453         }
454
455         /* Get signal to deliver.  When running under ptrace, at this point
456            the debugger may change all our registers ... */
457         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
458
459         /* Depending on the signal settings we may need to revert the
460            decision to restart the system call. */
461         if (signr > 0 && regs->psw.addr == restart_addr) {
462                 if (retval == -ERESTARTNOHAND
463                     || (retval == -ERESTARTSYS
464                          && !(current->sighand->action[signr-1].sa.sa_flags
465                               & SA_RESTART))) {
466                         regs->gprs[2] = -EINTR;
467                         regs->psw.addr = continue_addr;
468                 }
469         }
470
471         if (signr > 0) {
472                 /* Whee!  Actually deliver the signal.  */
473 #ifdef CONFIG_COMPAT
474                 if (test_thread_flag(TIF_31BIT)) {
475                         extern int handle_signal32(unsigned long sig,
476                                                    struct k_sigaction *ka,
477                                                    siginfo_t *info,
478                                                    sigset_t *oldset,
479                                                    struct pt_regs *regs);
480                         if (handle_signal32(
481                                     signr, &ka, &info, oldset, regs) == 0) {
482                                 if (test_thread_flag(TIF_RESTORE_SIGMASK))
483                                         clear_thread_flag(TIF_RESTORE_SIGMASK);
484                         }
485                         return;
486                 }
487 #endif
488                 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
489                         /*
490                          * A signal was successfully delivered; the saved
491                          * sigmask will have been stored in the signal frame,
492                          * and will be restored by sigreturn, so we can simply
493                          * clear the TIF_RESTORE_SIGMASK flag.
494                          */
495                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
496                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
497                 }
498                 return;
499         }
500
501         /*
502          * If there's no signal to deliver, we just put the saved sigmask back.
503          */
504         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
505                 clear_thread_flag(TIF_RESTORE_SIGMASK);
506                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
507         }
508
509         /* Restart a different system call. */
510         if (retval == -ERESTART_RESTARTBLOCK
511             && regs->psw.addr == continue_addr) {
512                 regs->gprs[2] = __NR_restart_syscall;
513                 set_thread_flag(TIF_RESTART_SVC);
514         }
515 }