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dccp: do not assume DCCP code is non preemptible
[linux/fpc-iii.git] / arch / alpha / kernel / signal.c
blob8dbfb15f17450501a80f6b3439e16aeab3546158
1 /*
2 * linux/arch/alpha/kernel/signal.c
3 *
4 * Copyright (C) 1995 Linus Torvalds
5 *
6 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
7 */
8
9 #include <linux/sched.h>
10 #include <linux/kernel.h>
11 #include <linux/signal.h>
12 #include <linux/errno.h>
13 #include <linux/wait.h>
14 #include <linux/ptrace.h>
15 #include <linux/unistd.h>
16 #include <linux/mm.h>
17 #include <linux/smp.h>
18 #include <linux/stddef.h>
19 #include <linux/tty.h>
20 #include <linux/binfmts.h>
21 #include <linux/bitops.h>
22 #include <linux/syscalls.h>
23 #include <linux/tracehook.h>
24
25 #include <asm/uaccess.h>
26 #include <asm/sigcontext.h>
27 #include <asm/ucontext.h>
28
29 #include "proto.h"
30
31
32 #define DEBUG_SIG 0
33
34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
35
36 asmlinkage void ret_from_sys_call(void);
37
38 /*
39 * The OSF/1 sigprocmask calling sequence is different from the
40 * C sigprocmask() sequence..
41 */
42 SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
43 {
44 sigset_t oldmask;
45 sigset_t mask;
46 unsigned long res;
47
48 siginitset(&mask, newmask & _BLOCKABLE);
49 res = sigprocmask(how, &mask, &oldmask);
50 if (!res) {
51 force_successful_syscall_return();
52 res = oldmask.sig[0];
53 }
54 return res;
55 }
56
57 SYSCALL_DEFINE3(osf_sigaction, int, sig,
58 const struct osf_sigaction __user *, act,
59 struct osf_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 (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
67 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
68 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
69 __get_user(mask, &act->sa_mask))
70 return -EFAULT;
71 siginitset(&new_ka.sa.sa_mask, mask);
72 new_ka.ka_restorer = NULL;
73 }
74
75 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
76
77 if (!ret && oact) {
78 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
79 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
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 return -EFAULT;
83 }
84
85 return ret;
86 }
87
88 SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
89 struct sigaction __user *, oact,
90 size_t, sigsetsize, void __user *, restorer)
91 {
92 struct k_sigaction new_ka, old_ka;
93 int ret;
94
95 /* XXX: Don't preclude handling different sized sigset_t's. */
96 if (sigsetsize != sizeof(sigset_t))
97 return -EINVAL;
98
99 if (act) {
100 new_ka.ka_restorer = restorer;
101 if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
102 return -EFAULT;
103 }
104
105 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
106
107 if (!ret && oact) {
108 if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
109 return -EFAULT;
110 }
111
112 return ret;
113 }
114
115 /*
116 * Do a signal return; undo the signal stack.
117 */
118
119 #if _NSIG_WORDS > 1
120 # error "Non SA_SIGINFO frame needs rearranging"
121 #endif
122
123 struct sigframe
124 {
125 struct sigcontext sc;
126 unsigned int retcode[3];
127 };
128
129 struct rt_sigframe
130 {
131 struct siginfo info;
132 struct ucontext uc;
133 unsigned int retcode[3];
134 };
135
136 /* If this changes, userland unwinders that Know Things about our signal
137 frame will break. Do not undertake lightly. It also implies an ABI
138 change wrt the size of siginfo_t, which may cause some pain. */
139 extern char compile_time_assert
140 [offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1];
141
142 #define INSN_MOV_R30_R16 0x47fe0410
143 #define INSN_LDI_R0 0x201f0000
144 #define INSN_CALLSYS 0x00000083
145
146 static long
147 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
148 {
149 unsigned long usp;
150 struct switch_stack *sw = (struct switch_stack *)regs - 1;
151 long i, err = __get_user(regs->pc, &sc->sc_pc);
152
153 current->restart_block.fn = do_no_restart_syscall;
154
155 sw->r26 = (unsigned long) ret_from_sys_call;
156
157 err |= __get_user(regs->r0, sc->sc_regs+0);
158 err |= __get_user(regs->r1, sc->sc_regs+1);
159 err |= __get_user(regs->r2, sc->sc_regs+2);
160 err |= __get_user(regs->r3, sc->sc_regs+3);
161 err |= __get_user(regs->r4, sc->sc_regs+4);
162 err |= __get_user(regs->r5, sc->sc_regs+5);
163 err |= __get_user(regs->r6, sc->sc_regs+6);
164 err |= __get_user(regs->r7, sc->sc_regs+7);
165 err |= __get_user(regs->r8, sc->sc_regs+8);
166 err |= __get_user(sw->r9, sc->sc_regs+9);
167 err |= __get_user(sw->r10, sc->sc_regs+10);
168 err |= __get_user(sw->r11, sc->sc_regs+11);
169 err |= __get_user(sw->r12, sc->sc_regs+12);
170 err |= __get_user(sw->r13, sc->sc_regs+13);
171 err |= __get_user(sw->r14, sc->sc_regs+14);
172 err |= __get_user(sw->r15, sc->sc_regs+15);
173 err |= __get_user(regs->r16, sc->sc_regs+16);
174 err |= __get_user(regs->r17, sc->sc_regs+17);
175 err |= __get_user(regs->r18, sc->sc_regs+18);
176 err |= __get_user(regs->r19, sc->sc_regs+19);
177 err |= __get_user(regs->r20, sc->sc_regs+20);
178 err |= __get_user(regs->r21, sc->sc_regs+21);
179 err |= __get_user(regs->r22, sc->sc_regs+22);
180 err |= __get_user(regs->r23, sc->sc_regs+23);
181 err |= __get_user(regs->r24, sc->sc_regs+24);
182 err |= __get_user(regs->r25, sc->sc_regs+25);
183 err |= __get_user(regs->r26, sc->sc_regs+26);
184 err |= __get_user(regs->r27, sc->sc_regs+27);
185 err |= __get_user(regs->r28, sc->sc_regs+28);
186 err |= __get_user(regs->gp, sc->sc_regs+29);
187 err |= __get_user(usp, sc->sc_regs+30);
188 wrusp(usp);
189
190 for (i = 0; i < 31; i++)
191 err |= __get_user(sw->fp[i], sc->sc_fpregs+i);
192 err |= __get_user(sw->fp[31], &sc->sc_fpcr);
193
194 return err;
195 }
196
197 /* Note that this syscall is also used by setcontext(3) to install
198 a given sigcontext. This because it's impossible to set *all*
199 registers and transfer control from userland. */
200
201 asmlinkage void
202 do_sigreturn(struct sigcontext __user *sc)
203 {
204 struct pt_regs *regs = current_pt_regs();
205 sigset_t set;
206
207 /* Verify that it's a good sigcontext before using it */
208 if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
209 goto give_sigsegv;
210 if (__get_user(set.sig[0], &sc->sc_mask))
211 goto give_sigsegv;
212
213 set_current_blocked(&set);
214
215 if (restore_sigcontext(sc, regs))
216 goto give_sigsegv;
217
218 /* Send SIGTRAP if we're single-stepping: */
219 if (ptrace_cancel_bpt (current)) {
220 siginfo_t info;
221
222 info.si_signo = SIGTRAP;
223 info.si_errno = 0;
224 info.si_code = TRAP_BRKPT;
225 info.si_addr = (void __user *) regs->pc;
226 info.si_trapno = 0;
227 send_sig_info(SIGTRAP, &info, current);
228 }
229 return;
230
231 give_sigsegv:
232 force_sig(SIGSEGV, current);
233 }
234
235 asmlinkage void
236 do_rt_sigreturn(struct rt_sigframe __user *frame)
237 {
238 struct pt_regs *regs = current_pt_regs();
239 sigset_t set;
240
241 /* Verify that it's a good ucontext_t before using it */
242 if (!access_ok(VERIFY_READ, &frame->uc, sizeof(frame->uc)))
243 goto give_sigsegv;
244 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
245 goto give_sigsegv;
246
247 set_current_blocked(&set);
248
249 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
250 goto give_sigsegv;
251
252 /* Send SIGTRAP if we're single-stepping: */
253 if (ptrace_cancel_bpt (current)) {
254 siginfo_t info;
255
256 info.si_signo = SIGTRAP;
257 info.si_errno = 0;
258 info.si_code = TRAP_BRKPT;
259 info.si_addr = (void __user *) regs->pc;
260 info.si_trapno = 0;
261 send_sig_info(SIGTRAP, &info, current);
262 }
263 return;
264
265 give_sigsegv:
266 force_sig(SIGSEGV, current);
267 }
268
269
270 /*
271 * Set up a signal frame.
272 */
273
274 static inline void __user *
275 get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
276 {
277 return (void __user *)((sigsp(sp, ksig) - frame_size) & -32ul);
278 }
279
280 static long
281 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
282 unsigned long mask, unsigned long sp)
283 {
284 struct switch_stack *sw = (struct switch_stack *)regs - 1;
285 long i, err = 0;
286
287 err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
288 err |= __put_user(mask, &sc->sc_mask);
289 err |= __put_user(regs->pc, &sc->sc_pc);
290 err |= __put_user(8, &sc->sc_ps);
291
292 err |= __put_user(regs->r0 , sc->sc_regs+0);
293 err |= __put_user(regs->r1 , sc->sc_regs+1);
294 err |= __put_user(regs->r2 , sc->sc_regs+2);
295 err |= __put_user(regs->r3 , sc->sc_regs+3);
296 err |= __put_user(regs->r4 , sc->sc_regs+4);
297 err |= __put_user(regs->r5 , sc->sc_regs+5);
298 err |= __put_user(regs->r6 , sc->sc_regs+6);
299 err |= __put_user(regs->r7 , sc->sc_regs+7);
300 err |= __put_user(regs->r8 , sc->sc_regs+8);
301 err |= __put_user(sw->r9 , sc->sc_regs+9);
302 err |= __put_user(sw->r10 , sc->sc_regs+10);
303 err |= __put_user(sw->r11 , sc->sc_regs+11);
304 err |= __put_user(sw->r12 , sc->sc_regs+12);
305 err |= __put_user(sw->r13 , sc->sc_regs+13);
306 err |= __put_user(sw->r14 , sc->sc_regs+14);
307 err |= __put_user(sw->r15 , sc->sc_regs+15);
308 err |= __put_user(regs->r16, sc->sc_regs+16);
309 err |= __put_user(regs->r17, sc->sc_regs+17);
310 err |= __put_user(regs->r18, sc->sc_regs+18);
311 err |= __put_user(regs->r19, sc->sc_regs+19);
312 err |= __put_user(regs->r20, sc->sc_regs+20);
313 err |= __put_user(regs->r21, sc->sc_regs+21);
314 err |= __put_user(regs->r22, sc->sc_regs+22);
315 err |= __put_user(regs->r23, sc->sc_regs+23);
316 err |= __put_user(regs->r24, sc->sc_regs+24);
317 err |= __put_user(regs->r25, sc->sc_regs+25);
318 err |= __put_user(regs->r26, sc->sc_regs+26);
319 err |= __put_user(regs->r27, sc->sc_regs+27);
320 err |= __put_user(regs->r28, sc->sc_regs+28);
321 err |= __put_user(regs->gp , sc->sc_regs+29);
322 err |= __put_user(sp, sc->sc_regs+30);
323 err |= __put_user(0, sc->sc_regs+31);
324
325 for (i = 0; i < 31; i++)
326 err |= __put_user(sw->fp[i], sc->sc_fpregs+i);
327 err |= __put_user(0, sc->sc_fpregs+31);
328 err |= __put_user(sw->fp[31], &sc->sc_fpcr);
329
330 err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0);
331 err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1);
332 err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2);
333
334 return err;
335 }
336
337 static int
338 setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
339 {
340 unsigned long oldsp, r26, err = 0;
341 struct sigframe __user *frame;
342
343 oldsp = rdusp();
344 frame = get_sigframe(ksig, oldsp, sizeof(*frame));
345 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
346 return -EFAULT;
347
348 err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);
349 if (err)
350 return -EFAULT;
351
352 /* Set up to return from userspace. If provided, use a stub
353 already in userspace. */
354 r26 = (unsigned long) ksig->ka.ka_restorer;
355 if (!r26) {
356 err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
357 err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1);
358 err |= __put_user(INSN_CALLSYS, frame->retcode+2);
359 imb();
360 r26 = (unsigned long) frame->retcode;
361 }
362
363 /* Check that everything was written properly. */
364 if (err)
365 return err;
366
367 /* "Return" to the handler */
368 regs->r26 = r26;
369 regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
370 regs->r16 = ksig->sig; /* a0: signal number */
371 regs->r17 = 0; /* a1: exception code */
372 regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */
373 wrusp((unsigned long) frame);
374
375 #if DEBUG_SIG
376 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
377 current->comm, current->pid, frame, regs->pc, regs->r26);
378 #endif
379 return 0;
380 }
381
382 static int
383 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
384 {
385 unsigned long oldsp, r26, err = 0;
386 struct rt_sigframe __user *frame;
387
388 oldsp = rdusp();
389 frame = get_sigframe(ksig, oldsp, sizeof(*frame));
390 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
391 return -EFAULT;
392
393 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
394
395 /* Create the ucontext. */
396 err |= __put_user(0, &frame->uc.uc_flags);
397 err |= __put_user(0, &frame->uc.uc_link);
398 err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
399 err |= __save_altstack(&frame->uc.uc_stack, oldsp);
400 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs,
401 set->sig[0], oldsp);
402 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
403 if (err)
404 return -EFAULT;
405
406 /* Set up to return from userspace. If provided, use a stub
407 already in userspace. */
408 r26 = (unsigned long) ksig->ka.ka_restorer;
409 if (!r26) {
410 err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
411 err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn,
412 frame->retcode+1);
413 err |= __put_user(INSN_CALLSYS, frame->retcode+2);
414 imb();
415 r26 = (unsigned long) frame->retcode;
416 }
417
418 if (err)
419 return -EFAULT;
420
421 /* "Return" to the handler */
422 regs->r26 = r26;
423 regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
424 regs->r16 = ksig->sig; /* a0: signal number */
425 regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */
426 regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */
427 wrusp((unsigned long) frame);
428
429 #if DEBUG_SIG
430 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
431 current->comm, current->pid, frame, regs->pc, regs->r26);
432 #endif
433
434 return 0;
435 }
436
437
438 /*
439 * OK, we're invoking a handler.
440 */
441 static inline void
442 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
443 {
444 sigset_t *oldset = sigmask_to_save();
445 int ret;
446
447 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
448 ret = setup_rt_frame(ksig, oldset, regs);
449 else
450 ret = setup_frame(ksig, oldset, regs);
451
452 signal_setup_done(ret, ksig, 0);
453 }
454
455 static inline void
456 syscall_restart(unsigned long r0, unsigned long r19,
457 struct pt_regs *regs, struct k_sigaction *ka)
458 {
459 switch (regs->r0) {
460 case ERESTARTSYS:
461 if (!(ka->sa.sa_flags & SA_RESTART)) {
462 case ERESTARTNOHAND:
463 regs->r0 = EINTR;
464 break;
465 }
466 /* fallthrough */
467 case ERESTARTNOINTR:
468 regs->r0 = r0; /* reset v0 and a3 and replay syscall */
469 regs->r19 = r19;
470 regs->pc -= 4;
471 break;
472 case ERESTART_RESTARTBLOCK:
473 regs->r0 = EINTR;
474 break;
475 }
476 }
477
478
479 /*
480 * Note that 'init' is a special process: it doesn't get signals it doesn't
481 * want to handle. Thus you cannot kill init even with a SIGKILL even by
482 * mistake.
483 *
484 * Note that we go through the signals twice: once to check the signals that
485 * the kernel can handle, and then we build all the user-level signal handling
486 * stack-frames in one go after that.
487 *
488 * "r0" and "r19" are the registers we need to restore for system call
489 * restart. "r0" is also used as an indicator whether we can restart at
490 * all (if we get here from anything but a syscall return, it will be 0)
491 */
492 static void
493 do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
494 {
495 unsigned long single_stepping = ptrace_cancel_bpt(current);
496 struct ksignal ksig;
497
498 /* This lets the debugger run, ... */
499 if (get_signal(&ksig)) {
500 /* ... so re-check the single stepping. */
501 single_stepping |= ptrace_cancel_bpt(current);
502 /* Whee! Actually deliver the signal. */
503 if (r0)
504 syscall_restart(r0, r19, regs, &ksig.ka);
505 handle_signal(&ksig, regs);
506 } else {
507 single_stepping |= ptrace_cancel_bpt(current);
508 if (r0) {
509 switch (regs->r0) {
510 case ERESTARTNOHAND:
511 case ERESTARTSYS:
512 case ERESTARTNOINTR:
513 /* Reset v0 and a3 and replay syscall. */
514 regs->r0 = r0;
515 regs->r19 = r19;
516 regs->pc -= 4;
517 break;
518 case ERESTART_RESTARTBLOCK:
519 /* Set v0 to the restart_syscall and replay */
520 regs->r0 = __NR_restart_syscall;
521 regs->pc -= 4;
522 break;
523 }
524 }
525 restore_saved_sigmask();
526 }
527 if (single_stepping)
528 ptrace_set_bpt(current); /* re-set breakpoint */
529 }
530
531 void
532 do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
533 unsigned long r0, unsigned long r19)
534 {
535 do {
536 if (thread_flags & _TIF_NEED_RESCHED) {
537 schedule();
538 } else {
539 local_irq_enable();
540 if (thread_flags & _TIF_SIGPENDING) {
541 do_signal(regs, r0, r19);
542 r0 = 0;
543 } else {
544 clear_thread_flag(TIF_NOTIFY_RESUME);
545 tracehook_notify_resume(regs);
546 }
547 }
548 local_irq_disable();
549 thread_flags = current_thread_info()->flags;
550 } while (thread_flags & _TIF_WORK_MASK);
551 }
Linux with added FPC-III support