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unify {de,}mangle_poll(), get rid of kernel-side POLL...
[cris-mirror.git] / arch / alpha / kernel / signal.c
blob9ebb3bcbc626b20150a1f6ca31b51563a6f3042a
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/arch/alpha/kernel/signal.c
4 *
5 * Copyright (C) 1995 Linus Torvalds
6 *
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
8 */
9
10 #include <linux/sched/signal.h>
11 #include <linux/sched/task_stack.h>
12 #include <linux/kernel.h>
13 #include <linux/signal.h>
14 #include <linux/errno.h>
15 #include <linux/wait.h>
16 #include <linux/ptrace.h>
17 #include <linux/unistd.h>
18 #include <linux/mm.h>
19 #include <linux/smp.h>
20 #include <linux/stddef.h>
21 #include <linux/tty.h>
22 #include <linux/binfmts.h>
23 #include <linux/bitops.h>
24 #include <linux/syscalls.h>
25 #include <linux/tracehook.h>
26
27 #include <linux/uaccess.h>
28 #include <asm/sigcontext.h>
29 #include <asm/ucontext.h>
30
31 #include "proto.h"
32
33
34 #define DEBUG_SIG 0
35
36 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
37
38 asmlinkage void ret_from_sys_call(void);
39
40 /*
41 * The OSF/1 sigprocmask calling sequence is different from the
42 * C sigprocmask() sequence..
43 */
44 SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
45 {
46 sigset_t oldmask;
47 sigset_t mask;
48 unsigned long res;
49
50 siginitset(&mask, newmask & _BLOCKABLE);
51 res = sigprocmask(how, &mask, &oldmask);
52 if (!res) {
53 force_successful_syscall_return();
54 res = oldmask.sig[0];
55 }
56 return res;
57 }
58
59 SYSCALL_DEFINE3(osf_sigaction, int, sig,
60 const struct osf_sigaction __user *, act,
61 struct osf_sigaction __user *, oact)
62 {
63 struct k_sigaction new_ka, old_ka;
64 int ret;
65
66 if (act) {
67 old_sigset_t mask;
68 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
69 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
70 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
71 __get_user(mask, &act->sa_mask))
72 return -EFAULT;
73 siginitset(&new_ka.sa.sa_mask, mask);
74 new_ka.ka_restorer = NULL;
75 }
76
77 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
78
79 if (!ret && oact) {
80 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
81 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
82 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
83 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
84 return -EFAULT;
85 }
86
87 return ret;
88 }
89
90 SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
91 struct sigaction __user *, oact,
92 size_t, sigsetsize, void __user *, restorer)
93 {
94 struct k_sigaction new_ka, old_ka;
95 int ret;
96
97 /* XXX: Don't preclude handling different sized sigset_t's. */
98 if (sigsetsize != sizeof(sigset_t))
99 return -EINVAL;
100
101 if (act) {
102 new_ka.ka_restorer = restorer;
103 if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
104 return -EFAULT;
105 }
106
107 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
108
109 if (!ret && oact) {
110 if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
111 return -EFAULT;
112 }
113
114 return ret;
115 }
116
117 /*
118 * Do a signal return; undo the signal stack.
119 */
120
121 #if _NSIG_WORDS > 1
122 # error "Non SA_SIGINFO frame needs rearranging"
123 #endif
124
125 struct sigframe
126 {
127 struct sigcontext sc;
128 unsigned int retcode[3];
129 };
130
131 struct rt_sigframe
132 {
133 struct siginfo info;
134 struct ucontext uc;
135 unsigned int retcode[3];
136 };
137
138 /* If this changes, userland unwinders that Know Things about our signal
139 frame will break. Do not undertake lightly. It also implies an ABI
140 change wrt the size of siginfo_t, which may cause some pain. */
141 extern char compile_time_assert
142 [offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1];
143
144 #define INSN_MOV_R30_R16 0x47fe0410
145 #define INSN_LDI_R0 0x201f0000
146 #define INSN_CALLSYS 0x00000083
147
148 static long
149 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
150 {
151 unsigned long usp;
152 struct switch_stack *sw = (struct switch_stack *)regs - 1;
153 long i, err = __get_user(regs->pc, &sc->sc_pc);
154
155 current->restart_block.fn = do_no_restart_syscall;
156
157 sw->r26 = (unsigned long) ret_from_sys_call;
158
159 err |= __get_user(regs->r0, sc->sc_regs+0);
160 err |= __get_user(regs->r1, sc->sc_regs+1);
161 err |= __get_user(regs->r2, sc->sc_regs+2);
162 err |= __get_user(regs->r3, sc->sc_regs+3);
163 err |= __get_user(regs->r4, sc->sc_regs+4);
164 err |= __get_user(regs->r5, sc->sc_regs+5);
165 err |= __get_user(regs->r6, sc->sc_regs+6);
166 err |= __get_user(regs->r7, sc->sc_regs+7);
167 err |= __get_user(regs->r8, sc->sc_regs+8);
168 err |= __get_user(sw->r9, sc->sc_regs+9);
169 err |= __get_user(sw->r10, sc->sc_regs+10);
170 err |= __get_user(sw->r11, sc->sc_regs+11);
171 err |= __get_user(sw->r12, sc->sc_regs+12);
172 err |= __get_user(sw->r13, sc->sc_regs+13);
173 err |= __get_user(sw->r14, sc->sc_regs+14);
174 err |= __get_user(sw->r15, sc->sc_regs+15);
175 err |= __get_user(regs->r16, sc->sc_regs+16);
176 err |= __get_user(regs->r17, sc->sc_regs+17);
177 err |= __get_user(regs->r18, sc->sc_regs+18);
178 err |= __get_user(regs->r19, sc->sc_regs+19);
179 err |= __get_user(regs->r20, sc->sc_regs+20);
180 err |= __get_user(regs->r21, sc->sc_regs+21);
181 err |= __get_user(regs->r22, sc->sc_regs+22);
182 err |= __get_user(regs->r23, sc->sc_regs+23);
183 err |= __get_user(regs->r24, sc->sc_regs+24);
184 err |= __get_user(regs->r25, sc->sc_regs+25);
185 err |= __get_user(regs->r26, sc->sc_regs+26);
186 err |= __get_user(regs->r27, sc->sc_regs+27);
187 err |= __get_user(regs->r28, sc->sc_regs+28);
188 err |= __get_user(regs->gp, sc->sc_regs+29);
189 err |= __get_user(usp, sc->sc_regs+30);
190 wrusp(usp);
191
192 for (i = 0; i < 31; i++)
193 err |= __get_user(sw->fp[i], sc->sc_fpregs+i);
194 err |= __get_user(sw->fp[31], &sc->sc_fpcr);
195
196 return err;
197 }
198
199 /* Note that this syscall is also used by setcontext(3) to install
200 a given sigcontext. This because it's impossible to set *all*
201 registers and transfer control from userland. */
202
203 asmlinkage void
204 do_sigreturn(struct sigcontext __user *sc)
205 {
206 struct pt_regs *regs = current_pt_regs();
207 sigset_t set;
208
209 /* Verify that it's a good sigcontext before using it */
210 if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
211 goto give_sigsegv;
212 if (__get_user(set.sig[0], &sc->sc_mask))
213 goto give_sigsegv;
214
215 set_current_blocked(&set);
216
217 if (restore_sigcontext(sc, regs))
218 goto give_sigsegv;
219
220 /* Send SIGTRAP if we're single-stepping: */
221 if (ptrace_cancel_bpt (current)) {
222 siginfo_t info;
223
224 info.si_signo = SIGTRAP;
225 info.si_errno = 0;
226 info.si_code = TRAP_BRKPT;
227 info.si_addr = (void __user *) regs->pc;
228 info.si_trapno = 0;
229 send_sig_info(SIGTRAP, &info, current);
230 }
231 return;
232
233 give_sigsegv:
234 force_sig(SIGSEGV, current);
235 }
236
237 asmlinkage void
238 do_rt_sigreturn(struct rt_sigframe __user *frame)
239 {
240 struct pt_regs *regs = current_pt_regs();
241 sigset_t set;
242
243 /* Verify that it's a good ucontext_t before using it */
244 if (!access_ok(VERIFY_READ, &frame->uc, sizeof(frame->uc)))
245 goto give_sigsegv;
246 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
247 goto give_sigsegv;
248
249 set_current_blocked(&set);
250
251 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
252 goto give_sigsegv;
253
254 /* Send SIGTRAP if we're single-stepping: */
255 if (ptrace_cancel_bpt (current)) {
256 siginfo_t info;
257
258 info.si_signo = SIGTRAP;
259 info.si_errno = 0;
260 info.si_code = TRAP_BRKPT;
261 info.si_addr = (void __user *) regs->pc;
262 info.si_trapno = 0;
263 send_sig_info(SIGTRAP, &info, current);
264 }
265 return;
266
267 give_sigsegv:
268 force_sig(SIGSEGV, current);
269 }
270
271
272 /*
273 * Set up a signal frame.
274 */
275
276 static inline void __user *
277 get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
278 {
279 return (void __user *)((sigsp(sp, ksig) - frame_size) & -32ul);
280 }
281
282 static long
283 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
284 unsigned long mask, unsigned long sp)
285 {
286 struct switch_stack *sw = (struct switch_stack *)regs - 1;
287 long i, err = 0;
288
289 err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
290 err |= __put_user(mask, &sc->sc_mask);
291 err |= __put_user(regs->pc, &sc->sc_pc);
292 err |= __put_user(8, &sc->sc_ps);
293
294 err |= __put_user(regs->r0 , sc->sc_regs+0);
295 err |= __put_user(regs->r1 , sc->sc_regs+1);
296 err |= __put_user(regs->r2 , sc->sc_regs+2);
297 err |= __put_user(regs->r3 , sc->sc_regs+3);
298 err |= __put_user(regs->r4 , sc->sc_regs+4);
299 err |= __put_user(regs->r5 , sc->sc_regs+5);
300 err |= __put_user(regs->r6 , sc->sc_regs+6);
301 err |= __put_user(regs->r7 , sc->sc_regs+7);
302 err |= __put_user(regs->r8 , sc->sc_regs+8);
303 err |= __put_user(sw->r9 , sc->sc_regs+9);
304 err |= __put_user(sw->r10 , sc->sc_regs+10);
305 err |= __put_user(sw->r11 , sc->sc_regs+11);
306 err |= __put_user(sw->r12 , sc->sc_regs+12);
307 err |= __put_user(sw->r13 , sc->sc_regs+13);
308 err |= __put_user(sw->r14 , sc->sc_regs+14);
309 err |= __put_user(sw->r15 , sc->sc_regs+15);
310 err |= __put_user(regs->r16, sc->sc_regs+16);
311 err |= __put_user(regs->r17, sc->sc_regs+17);
312 err |= __put_user(regs->r18, sc->sc_regs+18);
313 err |= __put_user(regs->r19, sc->sc_regs+19);
314 err |= __put_user(regs->r20, sc->sc_regs+20);
315 err |= __put_user(regs->r21, sc->sc_regs+21);
316 err |= __put_user(regs->r22, sc->sc_regs+22);
317 err |= __put_user(regs->r23, sc->sc_regs+23);
318 err |= __put_user(regs->r24, sc->sc_regs+24);
319 err |= __put_user(regs->r25, sc->sc_regs+25);
320 err |= __put_user(regs->r26, sc->sc_regs+26);
321 err |= __put_user(regs->r27, sc->sc_regs+27);
322 err |= __put_user(regs->r28, sc->sc_regs+28);
323 err |= __put_user(regs->gp , sc->sc_regs+29);
324 err |= __put_user(sp, sc->sc_regs+30);
325 err |= __put_user(0, sc->sc_regs+31);
326
327 for (i = 0; i < 31; i++)
328 err |= __put_user(sw->fp[i], sc->sc_fpregs+i);
329 err |= __put_user(0, sc->sc_fpregs+31);
330 err |= __put_user(sw->fp[31], &sc->sc_fpcr);
331
332 err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0);
333 err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1);
334 err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2);
335
336 return err;
337 }
338
339 static int
340 setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
341 {
342 unsigned long oldsp, r26, err = 0;
343 struct sigframe __user *frame;
344
345 oldsp = rdusp();
346 frame = get_sigframe(ksig, oldsp, sizeof(*frame));
347 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
348 return -EFAULT;
349
350 err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);
351 if (err)
352 return -EFAULT;
353
354 /* Set up to return from userspace. If provided, use a stub
355 already in userspace. */
356 r26 = (unsigned long) ksig->ka.ka_restorer;
357 if (!r26) {
358 err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
359 err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1);
360 err |= __put_user(INSN_CALLSYS, frame->retcode+2);
361 imb();
362 r26 = (unsigned long) frame->retcode;
363 }
364
365 /* Check that everything was written properly. */
366 if (err)
367 return err;
368
369 /* "Return" to the handler */
370 regs->r26 = r26;
371 regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
372 regs->r16 = ksig->sig; /* a0: signal number */
373 regs->r17 = 0; /* a1: exception code */
374 regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */
375 wrusp((unsigned long) frame);
376
377 #if DEBUG_SIG
378 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
379 current->comm, current->pid, frame, regs->pc, regs->r26);
380 #endif
381 return 0;
382 }
383
384 static int
385 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
386 {
387 unsigned long oldsp, r26, err = 0;
388 struct rt_sigframe __user *frame;
389
390 oldsp = rdusp();
391 frame = get_sigframe(ksig, oldsp, sizeof(*frame));
392 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
393 return -EFAULT;
394
395 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
396
397 /* Create the ucontext. */
398 err |= __put_user(0, &frame->uc.uc_flags);
399 err |= __put_user(0, &frame->uc.uc_link);
400 err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
401 err |= __save_altstack(&frame->uc.uc_stack, oldsp);
402 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs,
403 set->sig[0], oldsp);
404 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
405 if (err)
406 return -EFAULT;
407
408 /* Set up to return from userspace. If provided, use a stub
409 already in userspace. */
410 r26 = (unsigned long) ksig->ka.ka_restorer;
411 if (!r26) {
412 err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
413 err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn,
414 frame->retcode+1);
415 err |= __put_user(INSN_CALLSYS, frame->retcode+2);
416 imb();
417 r26 = (unsigned long) frame->retcode;
418 }
419
420 if (err)
421 return -EFAULT;
422
423 /* "Return" to the handler */
424 regs->r26 = r26;
425 regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
426 regs->r16 = ksig->sig; /* a0: signal number */
427 regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */
428 regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */
429 wrusp((unsigned long) frame);
430
431 #if DEBUG_SIG
432 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
433 current->comm, current->pid, frame, regs->pc, regs->r26);
434 #endif
435
436 return 0;
437 }
438
439
440 /*
441 * OK, we're invoking a handler.
442 */
443 static inline void
444 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
445 {
446 sigset_t *oldset = sigmask_to_save();
447 int ret;
448
449 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
450 ret = setup_rt_frame(ksig, oldset, regs);
451 else
452 ret = setup_frame(ksig, oldset, regs);
453
454 signal_setup_done(ret, ksig, 0);
455 }
456
457 static inline void
458 syscall_restart(unsigned long r0, unsigned long r19,
459 struct pt_regs *regs, struct k_sigaction *ka)
460 {
461 switch (regs->r0) {
462 case ERESTARTSYS:
463 if (!(ka->sa.sa_flags & SA_RESTART)) {
464 case ERESTARTNOHAND:
465 regs->r0 = EINTR;
466 break;
467 }
468 /* fallthrough */
469 case ERESTARTNOINTR:
470 regs->r0 = r0; /* reset v0 and a3 and replay syscall */
471 regs->r19 = r19;
472 regs->pc -= 4;
473 break;
474 case ERESTART_RESTARTBLOCK:
475 regs->r0 = EINTR;
476 break;
477 }
478 }
479
480
481 /*
482 * Note that 'init' is a special process: it doesn't get signals it doesn't
483 * want to handle. Thus you cannot kill init even with a SIGKILL even by
484 * mistake.
485 *
486 * Note that we go through the signals twice: once to check the signals that
487 * the kernel can handle, and then we build all the user-level signal handling
488 * stack-frames in one go after that.
489 *
490 * "r0" and "r19" are the registers we need to restore for system call
491 * restart. "r0" is also used as an indicator whether we can restart at
492 * all (if we get here from anything but a syscall return, it will be 0)
493 */
494 static void
495 do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
496 {
497 unsigned long single_stepping = ptrace_cancel_bpt(current);
498 struct ksignal ksig;
499
500 /* This lets the debugger run, ... */
501 if (get_signal(&ksig)) {
502 /* ... so re-check the single stepping. */
503 single_stepping |= ptrace_cancel_bpt(current);
504 /* Whee! Actually deliver the signal. */
505 if (r0)
506 syscall_restart(r0, r19, regs, &ksig.ka);
507 handle_signal(&ksig, regs);
508 } else {
509 single_stepping |= ptrace_cancel_bpt(current);
510 if (r0) {
511 switch (regs->r0) {
512 case ERESTARTNOHAND:
513 case ERESTARTSYS:
514 case ERESTARTNOINTR:
515 /* Reset v0 and a3 and replay syscall. */
516 regs->r0 = r0;
517 regs->r19 = r19;
518 regs->pc -= 4;
519 break;
520 case ERESTART_RESTARTBLOCK:
521 /* Set v0 to the restart_syscall and replay */
522 regs->r0 = __NR_restart_syscall;
523 regs->pc -= 4;
524 break;
525 }
526 }
527 restore_saved_sigmask();
528 }
529 if (single_stepping)
530 ptrace_set_bpt(current); /* re-set breakpoint */
531 }
532
533 void
534 do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
535 unsigned long r0, unsigned long r19)
536 {
537 do {
538 if (thread_flags & _TIF_NEED_RESCHED) {
539 schedule();
540 } else {
541 local_irq_enable();
542 if (thread_flags & _TIF_SIGPENDING) {
543 do_signal(regs, r0, r19);
544 r0 = 0;
545 } else {
546 clear_thread_flag(TIF_NOTIFY_RESUME);
547 tracehook_notify_resume(regs);
548 }
549 }
550 local_irq_disable();
551 thread_flags = current_thread_info()->flags;
552 } while (thread_flags & _TIF_WORK_MASK);
553 }
CRIS linux kernel tree