[PATCH] convert signal handling of NODEFER to act like other Unix boxes.
[linux-3.10.git] / arch / s390 / kernel / signal.c
1 /*
2  *  arch/s390/kernel/signal.c
3  *
4  *  S390 version
5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
7  *
8  *    Based on Intel version
9  * 
10  *  Copyright (C) 1991, 1992  Linus Torvalds
11  *
12  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
13  */
14
15 #include <linux/config.h>
16 #include <linux/sched.h>
17 #include <linux/mm.h>
18 #include <linux/smp.h>
19 #include <linux/smp_lock.h>
20 #include <linux/kernel.h>
21 #include <linux/signal.h>
22 #include <linux/errno.h>
23 #include <linux/wait.h>
24 #include <linux/ptrace.h>
25 #include <linux/unistd.h>
26 #include <linux/stddef.h>
27 #include <linux/tty.h>
28 #include <linux/personality.h>
29 #include <linux/binfmts.h>
30 #include <asm/ucontext.h>
31 #include <asm/uaccess.h>
32 #include <asm/lowcore.h>
33
34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
35
36
37 typedef struct 
38 {
39         __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
40         struct sigcontext sc;
41         _sigregs sregs;
42         int signo;
43         __u8 retcode[S390_SYSCALL_SIZE];
44 } sigframe;
45
46 typedef struct 
47 {
48         __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
49         __u8 retcode[S390_SYSCALL_SIZE];
50         struct siginfo info;
51         struct ucontext uc;
52 } rt_sigframe;
53
54 int do_signal(struct pt_regs *regs, sigset_t *oldset);
55
56 /*
57  * Atomically swap in the new signal mask, and wait for a signal.
58  */
59 asmlinkage int
60 sys_sigsuspend(struct pt_regs * regs, int history0, int history1,
61                old_sigset_t mask)
62 {
63         sigset_t saveset;
64
65         mask &= _BLOCKABLE;
66         spin_lock_irq(&current->sighand->siglock);
67         saveset = current->blocked;
68         siginitset(&current->blocked, mask);
69         recalc_sigpending();
70         spin_unlock_irq(&current->sighand->siglock);
71         regs->gprs[2] = -EINTR;
72
73         while (1) {
74                 set_current_state(TASK_INTERRUPTIBLE);
75                 schedule();
76                 if (do_signal(regs, &saveset))
77                         return -EINTR;
78         }
79 }
80
81 asmlinkage long
82 sys_rt_sigsuspend(struct pt_regs *regs, sigset_t __user *unewset,
83                                                 size_t sigsetsize)
84 {
85         sigset_t saveset, newset;
86
87         /* XXX: Don't preclude handling different sized sigset_t's.  */
88         if (sigsetsize != sizeof(sigset_t))
89                 return -EINVAL;
90
91         if (copy_from_user(&newset, unewset, sizeof(newset)))
92                 return -EFAULT;
93         sigdelsetmask(&newset, ~_BLOCKABLE);
94
95         spin_lock_irq(&current->sighand->siglock);
96         saveset = current->blocked;
97         current->blocked = newset;
98         recalc_sigpending();
99         spin_unlock_irq(&current->sighand->siglock);
100         regs->gprs[2] = -EINTR;
101
102         while (1) {
103                 set_current_state(TASK_INTERRUPTIBLE);
104                 schedule();
105                 if (do_signal(regs, &saveset))
106                         return -EINTR;
107         }
108 }
109
110 asmlinkage long
111 sys_sigaction(int sig, const struct old_sigaction __user *act,
112               struct old_sigaction __user *oact)
113 {
114         struct k_sigaction new_ka, old_ka;
115         int ret;
116
117         if (act) {
118                 old_sigset_t mask;
119                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
120                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
121                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
122                         return -EFAULT;
123                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
124                 __get_user(mask, &act->sa_mask);
125                 siginitset(&new_ka.sa.sa_mask, mask);
126         }
127
128         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
129
130         if (!ret && oact) {
131                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
132                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
133                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
134                         return -EFAULT;
135                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
136                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
137         }
138
139         return ret;
140 }
141
142 asmlinkage long
143 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
144                                         struct pt_regs *regs)
145 {
146         return do_sigaltstack(uss, uoss, regs->gprs[15]);
147 }
148
149
150
151 /* Returns non-zero on fault. */
152 static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
153 {
154         unsigned long old_mask = regs->psw.mask;
155         int err;
156   
157         save_access_regs(current->thread.acrs);
158
159         /* Copy a 'clean' PSW mask to the user to avoid leaking
160            information about whether PER is currently on.  */
161         regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
162         err = __copy_to_user(&sregs->regs.psw, &regs->psw,
163                              sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
164         regs->psw.mask = old_mask;
165         if (err != 0)
166                 return err;
167         err = __copy_to_user(&sregs->regs.acrs, current->thread.acrs,
168                              sizeof(sregs->regs.acrs));
169         if (err != 0)
170                 return err;
171         /* 
172          * We have to store the fp registers to current->thread.fp_regs
173          * to merge them with the emulated registers.
174          */
175         save_fp_regs(&current->thread.fp_regs);
176         return __copy_to_user(&sregs->fpregs, &current->thread.fp_regs,
177                               sizeof(s390_fp_regs));
178 }
179
180 /* Returns positive number on error */
181 static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
182 {
183         unsigned long old_mask = regs->psw.mask;
184         int err;
185
186         /* Alwys make any pending restarted system call return -EINTR */
187         current_thread_info()->restart_block.fn = do_no_restart_syscall;
188
189         err = __copy_from_user(&regs->psw, &sregs->regs.psw,
190                                sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
191         regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask);
192         regs->psw.addr |= PSW_ADDR_AMODE;
193         if (err)
194                 return err;
195         err = __copy_from_user(&current->thread.acrs, &sregs->regs.acrs,
196                                sizeof(sregs->regs.acrs));
197         if (err)
198                 return err;
199         restore_access_regs(current->thread.acrs);
200
201         err = __copy_from_user(&current->thread.fp_regs, &sregs->fpregs,
202                                sizeof(s390_fp_regs));
203         current->thread.fp_regs.fpc &= FPC_VALID_MASK;
204         if (err)
205                 return err;
206
207         restore_fp_regs(&current->thread.fp_regs);
208         regs->trap = -1;        /* disable syscall checks */
209         return 0;
210 }
211
212 asmlinkage long sys_sigreturn(struct pt_regs *regs)
213 {
214         sigframe __user *frame = (sigframe __user *)regs->gprs[15];
215         sigset_t set;
216
217         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
218                 goto badframe;
219         if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
220                 goto badframe;
221
222         sigdelsetmask(&set, ~_BLOCKABLE);
223         spin_lock_irq(&current->sighand->siglock);
224         current->blocked = set;
225         recalc_sigpending();
226         spin_unlock_irq(&current->sighand->siglock);
227
228         if (restore_sigregs(regs, &frame->sregs))
229                 goto badframe;
230
231         return regs->gprs[2];
232
233 badframe:
234         force_sig(SIGSEGV, current);
235         return 0;
236 }
237
238 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
239 {
240         rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
241         sigset_t set;
242
243         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
244                 goto badframe;
245         if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
246                 goto badframe;
247
248         sigdelsetmask(&set, ~_BLOCKABLE);
249         spin_lock_irq(&current->sighand->siglock);
250         current->blocked = set;
251         recalc_sigpending();
252         spin_unlock_irq(&current->sighand->siglock);
253
254         if (restore_sigregs(regs, &frame->uc.uc_mcontext))
255                 goto badframe;
256
257         /* It is more difficult to avoid calling this function than to
258            call it and ignore errors.  */
259         do_sigaltstack(&frame->uc.uc_stack, NULL, regs->gprs[15]);
260         return regs->gprs[2];
261
262 badframe:
263         force_sig(SIGSEGV, current);
264         return 0;
265 }
266
267 /*
268  * Set up a signal frame.
269  */
270
271
272 /*
273  * Determine which stack to use..
274  */
275 static inline void __user *
276 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
277 {
278         unsigned long sp;
279
280         /* Default to using normal stack */
281         sp = regs->gprs[15];
282
283         /* This is the X/Open sanctioned signal stack switching.  */
284         if (ka->sa.sa_flags & SA_ONSTACK) {
285                 if (! sas_ss_flags(sp))
286                         sp = current->sas_ss_sp + current->sas_ss_size;
287         }
288
289         /* This is the legacy signal stack switching. */
290         else if (!user_mode(regs) &&
291                  !(ka->sa.sa_flags & SA_RESTORER) &&
292                  ka->sa.sa_restorer) {
293                 sp = (unsigned long) ka->sa.sa_restorer;
294         }
295
296         return (void __user *)((sp - frame_size) & -8ul);
297 }
298
299 static inline int map_signal(int sig)
300 {
301         if (current_thread_info()->exec_domain
302             && current_thread_info()->exec_domain->signal_invmap
303             && sig < 32)
304                 return current_thread_info()->exec_domain->signal_invmap[sig];
305         else
306                 return sig;
307 }
308
309 static void setup_frame(int sig, struct k_sigaction *ka,
310                         sigset_t *set, struct pt_regs * regs)
311 {
312         sigframe __user *frame;
313
314         frame = get_sigframe(ka, regs, sizeof(sigframe));
315         if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
316                 goto give_sigsegv;
317
318         if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
319                 goto give_sigsegv;
320
321         if (save_sigregs(regs, &frame->sregs))
322                 goto give_sigsegv;
323         if (__put_user(&frame->sregs, &frame->sc.sregs))
324                 goto give_sigsegv;
325
326         /* Set up to return from userspace.  If provided, use a stub
327            already in userspace.  */
328         if (ka->sa.sa_flags & SA_RESTORER) {
329                 regs->gprs[14] = (unsigned long)
330                         ka->sa.sa_restorer | PSW_ADDR_AMODE;
331         } else {
332                 regs->gprs[14] = (unsigned long)
333                         frame->retcode | PSW_ADDR_AMODE;
334                 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
335                                (u16 __user *)(frame->retcode)))
336                         goto give_sigsegv;
337         }
338
339         /* Set up backchain. */
340         if (__put_user(regs->gprs[15], (addr_t __user *) frame))
341                 goto give_sigsegv;
342
343         /* Set up registers for signal handler */
344         regs->gprs[15] = (unsigned long) frame;
345         regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
346
347         regs->gprs[2] = map_signal(sig);
348         regs->gprs[3] = (unsigned long) &frame->sc;
349
350         /* We forgot to include these in the sigcontext.
351            To avoid breaking binary compatibility, they are passed as args. */
352         regs->gprs[4] = current->thread.trap_no;
353         regs->gprs[5] = current->thread.prot_addr;
354
355         /* Place signal number on stack to allow backtrace from handler.  */
356         if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
357                 goto give_sigsegv;
358         return;
359
360 give_sigsegv:
361         force_sigsegv(sig, current);
362 }
363
364 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
365                            sigset_t *set, struct pt_regs * regs)
366 {
367         int err = 0;
368         rt_sigframe __user *frame;
369
370         frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
371         if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
372                 goto give_sigsegv;
373
374         if (copy_siginfo_to_user(&frame->info, info))
375                 goto give_sigsegv;
376
377         /* Create the ucontext.  */
378         err |= __put_user(0, &frame->uc.uc_flags);
379         err |= __put_user(0, &frame->uc.uc_link);
380         err |= __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
381         err |= __put_user(sas_ss_flags(regs->gprs[15]),
382                           &frame->uc.uc_stack.ss_flags);
383         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
384         err |= save_sigregs(regs, &frame->uc.uc_mcontext);
385         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
386         if (err)
387                 goto give_sigsegv;
388
389         /* Set up to return from userspace.  If provided, use a stub
390            already in userspace.  */
391         if (ka->sa.sa_flags & SA_RESTORER) {
392                 regs->gprs[14] = (unsigned long)
393                         ka->sa.sa_restorer | PSW_ADDR_AMODE;
394         } else {
395                 regs->gprs[14] = (unsigned long)
396                         frame->retcode | PSW_ADDR_AMODE;
397                 err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
398                                   (u16 __user *)(frame->retcode));
399         }
400
401         /* Set up backchain. */
402         if (__put_user(regs->gprs[15], (addr_t __user *) frame))
403                 goto give_sigsegv;
404
405         /* Set up registers for signal handler */
406         regs->gprs[15] = (unsigned long) frame;
407         regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
408
409         regs->gprs[2] = map_signal(sig);
410         regs->gprs[3] = (unsigned long) &frame->info;
411         regs->gprs[4] = (unsigned long) &frame->uc;
412         return;
413
414 give_sigsegv:
415         force_sigsegv(sig, current);
416 }
417
418 /*
419  * OK, we're invoking a handler
420  */     
421
422 static void
423 handle_signal(unsigned long sig, struct k_sigaction *ka,
424               siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
425 {
426         /* Set up the stack frame */
427         if (ka->sa.sa_flags & SA_SIGINFO)
428                 setup_rt_frame(sig, ka, info, oldset, regs);
429         else
430                 setup_frame(sig, ka, oldset, regs);
431
432         spin_lock_irq(&current->sighand->siglock);
433         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
434         if (!(ka->sa.sa_flags & SA_NODEFER))
435                 sigaddset(&current->blocked,sig);
436         recalc_sigpending();
437         spin_unlock_irq(&current->sighand->siglock);
438 }
439
440 /*
441  * Note that 'init' is a special process: it doesn't get signals it doesn't
442  * want to handle. Thus you cannot kill init even with a SIGKILL even by
443  * mistake.
444  *
445  * Note that we go through the signals twice: once to check the signals that
446  * the kernel can handle, and then we build all the user-level signal handling
447  * stack-frames in one go after that.
448  */
449 int do_signal(struct pt_regs *regs, sigset_t *oldset)
450 {
451         unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
452         siginfo_t info;
453         int signr;
454         struct k_sigaction ka;
455
456         /*
457          * We want the common case to go fast, which
458          * is why we may in certain cases get here from
459          * kernel mode. Just return without doing anything
460          * if so.
461          */
462         if (!user_mode(regs))
463                 return 1;
464
465         if (!oldset)
466                 oldset = &current->blocked;
467
468         /* Are we from a system call? */
469         if (regs->trap == __LC_SVC_OLD_PSW) {
470                 continue_addr = regs->psw.addr;
471                 restart_addr = continue_addr - regs->ilc;
472                 retval = regs->gprs[2];
473
474                 /* Prepare for system call restart.  We do this here so that a
475                    debugger will see the already changed PSW. */
476                 if (retval == -ERESTARTNOHAND ||
477                     retval == -ERESTARTSYS ||
478                     retval == -ERESTARTNOINTR) {
479                         regs->gprs[2] = regs->orig_gpr2;
480                         regs->psw.addr = restart_addr;
481                 } else if (retval == -ERESTART_RESTARTBLOCK) {
482                         regs->gprs[2] = -EINTR;
483                 }
484         }
485
486         /* Get signal to deliver.  When running under ptrace, at this point
487            the debugger may change all our registers ... */
488         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
489
490         /* Depending on the signal settings we may need to revert the
491            decision to restart the system call. */
492         if (signr > 0 && regs->psw.addr == restart_addr) {
493                 if (retval == -ERESTARTNOHAND
494                     || (retval == -ERESTARTSYS
495                          && !(current->sighand->action[signr-1].sa.sa_flags
496                               & SA_RESTART))) {
497                         regs->gprs[2] = -EINTR;
498                         regs->psw.addr = continue_addr;
499                 }
500         }
501
502         if (signr > 0) {
503                 /* Whee!  Actually deliver the signal.  */
504 #ifdef CONFIG_S390_SUPPORT
505                 if (test_thread_flag(TIF_31BIT)) {
506                         extern void handle_signal32(unsigned long sig,
507                                                     struct k_sigaction *ka,
508                                                     siginfo_t *info,
509                                                     sigset_t *oldset,
510                                                     struct pt_regs *regs);
511                         handle_signal32(signr, &ka, &info, oldset, regs);
512                         return 1;
513                 }
514 #endif
515                 handle_signal(signr, &ka, &info, oldset, regs);
516                 return 1;
517         }
518
519         /* Restart a different system call. */
520         if (retval == -ERESTART_RESTARTBLOCK
521             && regs->psw.addr == continue_addr) {
522                 regs->gprs[2] = __NR_restart_syscall;
523                 set_thread_flag(TIF_RESTART_SVC);
524         }
525         return 0;
526 }