/arch/mn10300/kernel/signal.c

  1/* MN10300 Signal handling
  2 *
  3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  4 * Written by David Howells (dhowells@redhat.com)
  5 *
  6 * This program is free software; you can redistribute it and/or
  7 * modify it under the terms of the GNU General Public Licence
  8 * as published by the Free Software Foundation; either version
  9 * 2 of the Licence, or (at your option) any later version.
 10 */
 11
 12#include <linux/sched.h>
 13#include <linux/mm.h>
 14#include <linux/smp.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/personality.h>
 24#include <linux/suspend.h>
 25#include <linux/tracehook.h>
 26#include <asm/cacheflush.h>
 27#include <asm/ucontext.h>
 28#include <asm/uaccess.h>
 29#include <asm/fpu.h>
 30#include "sigframe.h"
 31
 32#define DEBUG_SIG 0
 33
 34#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 35
 36/*
 37 * atomically swap in the new signal mask, and wait for a signal.
 38 */
 39asmlinkage long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 40{
 41	mask &= _BLOCKABLE;
 42	spin_lock_irq(&current->sighand->siglock);
 43	current->saved_sigmask = current->blocked;
 44	siginitset(&current->blocked, mask);
 45	recalc_sigpending();
 46	spin_unlock_irq(&current->sighand->siglock);
 47
 48	current->state = TASK_INTERRUPTIBLE;
 49	schedule();
 50	set_thread_flag(TIF_RESTORE_SIGMASK);
 51	return -ERESTARTNOHAND;
 52}
 53
 54/*
 55 * set signal action syscall
 56 */
 57asmlinkage long sys_sigaction(int sig,
 58			      const struct old_sigaction __user *act,
 59			      struct old_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 (verify_area(VERIFY_READ, act, sizeof(*act)) ||
 67		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 68		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 69			return -EFAULT;
 70		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
 71		__get_user(mask, &act->sa_mask);
 72		siginitset(&new_ka.sa.sa_mask, mask);
 73	}
 74
 75	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 76
 77	if (!ret && oact) {
 78		if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
 79		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 80		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 81			return -EFAULT;
 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	}
 85
 86	return ret;
 87}
 88
 89/*
 90 * set alternate signal stack syscall
 91 */
 92asmlinkage long sys_sigaltstack(const stack_t __user *uss, stack_t *uoss)
 93{
 94	return do_sigaltstack(uss, uoss, __frame->sp);
 95}
 96
 97/*
 98 * do a signal return; undo the signal stack.
 99 */
100static int restore_sigcontext(struct pt_regs *regs,
101			      struct sigcontext __user *sc, long *_d0)
102{
103	unsigned int err = 0;
104
105	if (is_using_fpu(current))
106		fpu_kill_state(current);
107
108#define COPY(x) err |= __get_user(regs->x, &sc->x)
109	COPY(d1); COPY(d2); COPY(d3);
110	COPY(a0); COPY(a1); COPY(a2); COPY(a3);
111	COPY(e0); COPY(e1); COPY(e2); COPY(e3);
112	COPY(e4); COPY(e5); COPY(e6); COPY(e7);
113	COPY(lar); COPY(lir);
114	COPY(mdr); COPY(mdrq);
115	COPY(mcvf); COPY(mcrl); COPY(mcrh);
116	COPY(sp); COPY(pc);
117#undef COPY
118
119	{
120		unsigned int tmpflags;
121#ifndef CONFIG_MN10300_USING_JTAG
122#define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
123		   EPSW_T | EPSW_nAR)
124#else
125#define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
126		   EPSW_nAR)
127#endif
128		err |= __get_user(tmpflags, &sc->epsw);
129		regs->epsw = (regs->epsw & ~USER_EPSW) |
130		  (tmpflags & USER_EPSW);
131		regs->orig_d0 = -1;		/* disable syscall checks */
132	}
133
134	{
135		struct fpucontext *buf;
136		err |= __get_user(buf, &sc->fpucontext);
137		if (buf) {
138			if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
139				goto badframe;
140			err |= fpu_restore_sigcontext(buf);
141		}
142	}
143
144	err |= __get_user(*_d0, &sc->d0);
145	return err;
146
147badframe:
148	return 1;
149}
150
151/*
152 * standard signal return syscall
153 */
154asmlinkage long sys_sigreturn(void)
155{
156	struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
157	sigset_t set;
158	long d0;
159
160	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
161		goto badframe;
162	if (__get_user(set.sig[0], &frame->sc.oldmask))
163		goto badframe;
164
165	if (_NSIG_WORDS > 1 &&
166	    __copy_from_user(&set.sig[1], &frame->extramask,
167			     sizeof(frame->extramask)))
168		goto badframe;
169
170	sigdelsetmask(&set, ~_BLOCKABLE);
171	spin_lock_irq(&current->sighand->siglock);
172	current->blocked = set;
173	recalc_sigpending();
174	spin_unlock_irq(&current->sighand->siglock);
175
176	if (restore_sigcontext(__frame, &frame->sc, &d0))
177		goto badframe;
178
179	return d0;
180
181badframe:
182	force_sig(SIGSEGV, current);
183	return 0;
184}
185
186/*
187 * realtime signal return syscall
188 */
189asmlinkage long sys_rt_sigreturn(void)
190{
191	struct rt_sigframe __user *frame =
192		(struct rt_sigframe __user *) __frame->sp;
193	sigset_t set;
194	unsigned long d0;
195
196	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
197		goto badframe;
198	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
199		goto badframe;
200
201	sigdelsetmask(&set, ~_BLOCKABLE);
202	spin_lock_irq(&current->sighand->siglock);
203	current->blocked = set;
204	recalc_sigpending();
205	spin_unlock_irq(&current->sighand->siglock);
206
207	if (restore_sigcontext(__frame, &frame->uc.uc_mcontext, &d0))
208		goto badframe;
209
210	if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
211		goto badframe;
212
213	return d0;
214
215badframe:
216	force_sig(SIGSEGV, current);
217	return 0;
218}
219
220/*
221 * store the userspace context into a signal frame
222 */
223static int setup_sigcontext(struct sigcontext __user *sc,
224			    struct fpucontext *fpuctx,
225			    struct pt_regs *regs,
226			    unsigned long mask)
227{
228	int tmp, err = 0;
229
230#define COPY(x) err |= __put_user(regs->x, &sc->x)
231	COPY(d0); COPY(d1); COPY(d2); COPY(d3);
232	COPY(a0); COPY(a1); COPY(a2); COPY(a3);
233	COPY(e0); COPY(e1); COPY(e2); COPY(e3);
234	COPY(e4); COPY(e5); COPY(e6); COPY(e7);
235	COPY(lar); COPY(lir);
236	COPY(mdr); COPY(mdrq);
237	COPY(mcvf); COPY(mcrl); COPY(mcrh);
238	COPY(sp); COPY(epsw); COPY(pc);
239#undef COPY
240
241	tmp = fpu_setup_sigcontext(fpuctx);
242	if (tmp < 0)
243		err = 1;
244	else
245		err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);
246
247	/* non-iBCS2 extensions.. */
248	err |= __put_user(mask, &sc->oldmask);
249
250	return err;
251}
252
253/*
254 * determine which stack to use..
255 */
256static inline void __user *get_sigframe(struct k_sigaction *ka,
257					struct pt_regs *regs,
258					size_t frame_size)
259{
260	unsigned long sp;
261
262	/* default to using normal stack */
263	sp = regs->sp;
264
265	/* this is the X/Open sanctioned signal stack switching.  */
266	if (ka->sa.sa_flags & SA_ONSTACK) {
267		if (sas_ss_flags(sp) == 0)
268			sp = current->sas_ss_sp + current->sas_ss_size;
269	}
270
271	return (void __user *) ((sp - frame_size) & ~7UL);
272}
273
274/*
275 * set up a normal signal frame
276 */
277static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
278		       struct pt_regs *regs)
279{
280	struct sigframe __user *frame;
281	int rsig;
282
283	frame = get_sigframe(ka, regs, sizeof(*frame));
284
285	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
286		goto give_sigsegv;
287
288	rsig = sig;
289	if (sig < 32 &&
290	    current_thread_info()->exec_domain &&
291	    current_thread_info()->exec_domain->signal_invmap)
292		rsig = current_thread_info()->exec_domain->signal_invmap[sig];
293
294	if (__put_user(rsig, &frame->sig) < 0 ||
295	    __put_user(&frame->sc, &frame->psc) < 0)
296		goto give_sigsegv;
297
298	if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
299		goto give_sigsegv;
300
301	if (_NSIG_WORDS > 1) {
302		if (__copy_to_user(frame->extramask, &set->sig[1],
303				   sizeof(frame->extramask)))
304			goto give_sigsegv;
305	}
306
307	/* set up to return from userspace.  If provided, use a stub already in
308	 * userspace */
309	if (ka->sa.sa_flags & SA_RESTORER) {
310		if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
311			goto give_sigsegv;
312	} else {
313		if (__put_user((void (*)(void))frame->retcode,
314			       &frame->pretcode))
315			goto give_sigsegv;
316		/* this is mov $,d0; syscall 0 */
317		if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
318		    __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
319		    __put_user(0x00, (char *)(frame->retcode + 2)) ||
320		    __put_user(0xf0, (char *)(frame->retcode + 3)) ||
321		    __put_user(0xe0, (char *)(frame->retcode + 4)))
322			goto give_sigsegv;
323		flush_icache_range((unsigned long) frame->retcode,
324				   (unsigned long) frame->retcode + 5);
325	}
326
327	/* set up registers for signal handler */
328	regs->sp = (unsigned long) frame;
329	regs->pc = (unsigned long) ka->sa.sa_handler;
330	regs->d0 = sig;
331	regs->d1 = (unsigned long) &frame->sc;
332
333	set_fs(USER_DS);
334
335	/* the tracer may want to single-step inside the handler */
336	if (test_thread_flag(TIF_SINGLESTEP))
337		ptrace_notify(SIGTRAP);
338
339#if DEBUG_SIG
340	printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
341	       sig, current->comm, current->pid, frame, regs->pc,
342	       frame->pretcode);
343#endif
344
345	return 0;
346
347give_sigsegv:
348	force_sig(SIGSEGV, current);
349	return -EFAULT;
350}
351
352/*
353 * set up a realtime signal frame
354 */
355static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
356			  sigset_t *set, struct pt_regs *regs)
357{
358	struct rt_sigframe __user *frame;
359	int rsig;
360
361	frame = get_sigframe(ka, regs, sizeof(*frame));
362
363	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
364		goto give_sigsegv;
365
366	rsig = sig;
367	if (sig < 32 &&
368	    current_thread_info()->exec_domain &&
369	    current_thread_info()->exec_domain->signal_invmap)
370		rsig = current_thread_info()->exec_domain->signal_invmap[sig];
371
372	if (__put_user(rsig, &frame->sig) ||
373	    __put_user(&frame->info, &frame->pinfo) ||
374	    __put_user(&frame->uc, &frame->puc) ||
375	    copy_siginfo_to_user(&frame->info, info))
376		goto give_sigsegv;
377
378	/* create the ucontext.  */
379	if (__put_user(0, &frame->uc.uc_flags) ||
380	    __put_user(0, &frame->uc.uc_link) ||
381	    __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
382	    __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
383	    __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size) ||
384	    setup_sigcontext(&frame->uc.uc_mcontext,
385			     &frame->fpuctx, regs, set->sig[0]) ||
386	    __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
387		goto give_sigsegv;
388
389	/* set up to return from userspace.  If provided, use a stub already in
390	 * userspace */
391	if (ka->sa.sa_flags & SA_RESTORER) {
392		if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
393			goto give_sigsegv;
394	} else {
395		if (__put_user((void(*)(void))frame->retcode,
396			       &frame->pretcode) ||
397		    /* This is mov $,d0; syscall 0 */
398		    __put_user(0x2c, (char *)(frame->retcode + 0)) ||
399		    __put_user(__NR_rt_sigreturn,
400			       (char *)(frame->retcode + 1)) ||
401		    __put_user(0x00, (char *)(frame->retcode + 2)) ||
402		    __put_user(0xf0, (char *)(frame->retcode + 3)) ||
403		    __put_user(0xe0, (char *)(frame->retcode + 4)))
404			goto give_sigsegv;
405
406		flush_icache_range((u_long) frame->retcode,
407				   (u_long) frame->retcode + 5);
408	}
409
410	/* Set up registers for signal handler */
411	regs->sp = (unsigned long) frame;
412	regs->pc = (unsigned long) ka->sa.sa_handler;
413	regs->d0 = sig;
414	regs->d1 = (long) &frame->info;
415
416	set_fs(USER_DS);
417
418	/* the tracer may want to single-step inside the handler */
419	if (test_thread_flag(TIF_SINGLESTEP))
420		ptrace_notify(SIGTRAP);
421
422#if DEBUG_SIG
423	printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
424	       sig, current->comm, current->pid, frame, regs->pc,
425	       frame->pretcode);
426#endif
427
428	return 0;
429
430give_sigsegv:
431	force_sig(SIGSEGV, current);
432	return -EFAULT;
433}
434
435/*
436 * handle the actual delivery of a signal to userspace
437 */
438static int handle_signal(int sig,
439			 siginfo_t *info, struct k_sigaction *ka,
440			 sigset_t *oldset, struct pt_regs *regs)
441{
442	int ret;
443
444	/* Are we from a system call? */
445	if (regs->orig_d0 >= 0) {
446		/* If so, check system call restarting.. */
447		switch (regs->d0) {
448		case -ERESTART_RESTARTBLOCK:
449		case -ERESTARTNOHAND:
450			regs->d0 = -EINTR;
451			break;
452
453		case -ERESTARTSYS:
454			if (!(ka->sa.sa_flags & SA_RESTART)) {
455				regs->d0 = -EINTR;
456				break;
457			}
458
459			/* fallthrough */
460		case -ERESTARTNOINTR:
461			regs->d0 = regs->orig_d0;
462			regs->pc -= 2;
463		}
464	}
465
466	/* Set up the stack frame */
467	if (ka->sa.sa_flags & SA_SIGINFO)
468		ret = setup_rt_frame(sig, ka, info, oldset, regs);
469	else
470		ret = setup_frame(sig, ka, oldset, regs);
471
472	if (ret == 0) {
473		spin_lock_irq(&current->sighand->siglock);
474		sigorsets(&current->blocked, &current->blocked,
475			  &ka->sa.sa_mask);
476		if (!(ka->sa.sa_flags & SA_NODEFER))
477			sigaddset(&current->blocked, sig);
478		recalc_sigpending();
479		spin_unlock_irq(&current->sighand->siglock);
480	}
481
482	return ret;
483}
484
485/*
486 * handle a potential signal
487 */
488static void do_signal(struct pt_regs *regs)
489{
490	struct k_sigaction ka;
491	siginfo_t info;
492	sigset_t *oldset;
493	int signr;
494
495	/* we want the common case to go fast, which is why we may in certain
496	 * cases get here from kernel mode */
497	if (!user_mode(regs))
498		return;
499
500	if (test_thread_flag(TIF_RESTORE_SIGMASK))
501		oldset = &current->saved_sigmask;
502	else
503		oldset = &current->blocked;
504
505	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
506	if (signr > 0) {
507		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
508			/* a signal was successfully delivered; the saved
509			 * sigmask will have been stored in the signal frame,
510			 * and will be restored by sigreturn, so we can simply
511			 * clear the TIF_RESTORE_SIGMASK flag */
512			if (test_thread_flag(TIF_RESTORE_SIGMASK))
513				clear_thread_flag(TIF_RESTORE_SIGMASK);
514
515			tracehook_signal_handler(signr, &info, &ka, regs,
516						 test_thread_flag(TIF_SINGLESTEP));
517		}
518
519		return;
520	}
521
522	/* did we come from a system call? */
523	if (regs->orig_d0 >= 0) {
524		/* restart the system call - no handlers present */
525		switch (regs->d0) {
526		case -ERESTARTNOHAND:
527		case -ERESTARTSYS:
528		case -ERESTARTNOINTR:
529			regs->d0 = regs->orig_d0;
530			regs->pc -= 2;
531			break;
532
533		case -ERESTART_RESTARTBLOCK:
534			regs->d0 = __NR_restart_syscall;
535			regs->pc -= 2;
536			break;
537		}
538	}
539
540	/* if there's no signal to deliver, we just put the saved sigmask
541	 * back */
542	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
543		clear_thread_flag(TIF_RESTORE_SIGMASK);
544		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
545	}
546}
547
548/*
549 * notification of userspace execution resumption
550 * - triggered by current->work.notify_resume
551 */
552asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
553{
554	/* Pending single-step? */
555	if (thread_info_flags & _TIF_SINGLESTEP) {
556#ifndef CONFIG_MN10300_USING_JTAG
557		regs->epsw |= EPSW_T;
558		clear_thread_flag(TIF_SINGLESTEP);
559#else
560		BUG(); /* no h/w single-step if using JTAG unit */
561#endif
562	}
563
564	/* deal with pending signal delivery */
565	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
566		do_signal(regs);
567
568	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
569		clear_thread_flag(TIF_NOTIFY_RESUME);
570		tracehook_notify_resume(__frame);
571		if (current->replacement_session_keyring)
572			key_replace_session_keyring();
573	}
574}