PageRenderTime 92ms CodeModel.GetById 34ms app.highlight 52ms RepoModel.GetById 1ms app.codeStats 0ms

/arch/frv/kernel/signal.c

https://bitbucket.org/evzijst/gittest
C | 588 lines | 390 code | 100 blank | 98 comment | 74 complexity | 05d58000795af1909ef8a9963f974816 MD5 | raw file
  1/* signal.c: FRV specific bits of signal handling
  2 *
  3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
  4 * Written by David Howells (dhowells@redhat.com)
  5 * - Derived from arch/m68k/kernel/signal.c
  6 *
  7 * This program is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU General Public License
  9 * as published by the Free Software Foundation; either version
 10 * 2 of the License, or (at your option) any later version.
 11 */
 12
 13#include <linux/sched.h>
 14#include <linux/mm.h>
 15#include <linux/smp.h>
 16#include <linux/smp_lock.h>
 17#include <linux/kernel.h>
 18#include <linux/signal.h>
 19#include <linux/errno.h>
 20#include <linux/wait.h>
 21#include <linux/ptrace.h>
 22#include <linux/unistd.h>
 23#include <linux/personality.h>
 24#include <linux/suspend.h>
 25#include <asm/ucontext.h>
 26#include <asm/uaccess.h>
 27#include <asm/cacheflush.h>
 28
 29#define DEBUG_SIG 0
 30
 31#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 32
 33struct fdpic_func_descriptor {
 34	unsigned long	text;
 35	unsigned long	GOT;
 36};
 37
 38asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
 39
 40/*
 41 * Atomically swap in the new signal mask, and wait for a signal.
 42 */
 43asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 44{
 45	sigset_t saveset;
 46
 47	mask &= _BLOCKABLE;
 48	spin_lock_irq(&current->sighand->siglock);
 49	saveset = current->blocked;
 50	siginitset(&current->blocked, mask);
 51	recalc_sigpending();
 52	spin_unlock_irq(&current->sighand->siglock);
 53
 54	__frame->gr8 = -EINTR;
 55	while (1) {
 56		current->state = TASK_INTERRUPTIBLE;
 57		schedule();
 58		if (do_signal(__frame, &saveset))
 59			/* return the signal number as the return value of this function
 60			 * - this is an utterly evil hack. syscalls should not invoke do_signal()
 61			 *   as entry.S sets regs->gr8 to the return value of the system call
 62			 * - we can't just use sigpending() as we'd have to discard SIG_IGN signals
 63			 *   and call waitpid() if SIGCHLD needed discarding
 64			 * - this only works on the i386 because it passes arguments to the signal
 65			 *   handler on the stack, and the return value in EAX is effectively
 66			 *   discarded
 67			 */
 68			return __frame->gr8;
 69	}
 70}
 71
 72asmlinkage int sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
 73{
 74	sigset_t saveset, newset;
 75
 76	/* XXX: Don't preclude handling different sized sigset_t's.  */
 77	if (sigsetsize != sizeof(sigset_t))
 78		return -EINVAL;
 79
 80	if (copy_from_user(&newset, unewset, sizeof(newset)))
 81		return -EFAULT;
 82	sigdelsetmask(&newset, ~_BLOCKABLE);
 83
 84	spin_lock_irq(&current->sighand->siglock);
 85	saveset = current->blocked;
 86	current->blocked = newset;
 87	recalc_sigpending();
 88	spin_unlock_irq(&current->sighand->siglock);
 89
 90	__frame->gr8 = -EINTR;
 91	while (1) {
 92		current->state = TASK_INTERRUPTIBLE;
 93		schedule();
 94		if (do_signal(__frame, &saveset))
 95			/* return the signal number as the return value of this function
 96			 * - this is an utterly evil hack. syscalls should not invoke do_signal()
 97			 *   as entry.S sets regs->gr8 to the return value of the system call
 98			 * - we can't just use sigpending() as we'd have to discard SIG_IGN signals
 99			 *   and call waitpid() if SIGCHLD needed discarding
100			 * - this only works on the i386 because it passes arguments to the signal
101			 *   handler on the stack, and the return value in EAX is effectively
102			 *   discarded
103			 */
104			return __frame->gr8;
105	}
106}
107
108asmlinkage int sys_sigaction(int sig,
109			     const struct old_sigaction __user *act,
110			     struct old_sigaction __user *oact)
111{
112	struct k_sigaction new_ka, old_ka;
113	int ret;
114
115	if (act) {
116		old_sigset_t mask;
117		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
118		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
119		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
120			return -EFAULT;
121		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
122		__get_user(mask, &act->sa_mask);
123		siginitset(&new_ka.sa.sa_mask, mask);
124	}
125
126	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
127
128	if (!ret && oact) {
129		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
130		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
131		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
132			return -EFAULT;
133		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
134		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
135	}
136
137	return ret;
138}
139
140asmlinkage
141int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
142{
143	return do_sigaltstack(uss, uoss, __frame->sp);
144}
145
146
147/*
148 * Do a signal return; undo the signal stack.
149 */
150
151struct sigframe
152{
153	void (*pretcode)(void);
154	int sig;
155	struct sigcontext sc;
156	unsigned long extramask[_NSIG_WORDS-1];
157	uint32_t retcode[2];
158};
159
160struct rt_sigframe
161{
162	void (*pretcode)(void);
163	int sig;
164	struct siginfo *pinfo;
165	void *puc;
166	struct siginfo info;
167	struct ucontext uc;
168	uint32_t retcode[2];
169};
170
171static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
172{
173	struct user_context *user = current->thread.user;
174	unsigned long tbr, psr;
175
176	tbr = user->i.tbr;
177	psr = user->i.psr;
178	if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
179		goto badframe;
180	user->i.tbr = tbr;
181	user->i.psr = psr;
182
183	restore_user_regs(user);
184
185	user->i.syscallno = -1;		/* disable syscall checks */
186
187	*_gr8 = user->i.gr[8];
188	return 0;
189
190 badframe:
191	return 1;
192}
193
194asmlinkage int sys_sigreturn(void)
195{
196	struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
197	sigset_t set;
198	int gr8;
199
200	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
201		goto badframe;
202	if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
203		goto badframe;
204
205	if (_NSIG_WORDS > 1 &&
206	    __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
207		goto badframe;
208
209	sigdelsetmask(&set, ~_BLOCKABLE);
210	spin_lock_irq(&current->sighand->siglock);
211	current->blocked = set;
212	recalc_sigpending();
213	spin_unlock_irq(&current->sighand->siglock);
214
215	if (restore_sigcontext(&frame->sc, &gr8))
216		goto badframe;
217	return gr8;
218
219 badframe:
220	force_sig(SIGSEGV, current);
221	return 0;
222}
223
224asmlinkage int sys_rt_sigreturn(void)
225{
226	struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
227	sigset_t set;
228	int gr8;
229
230	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
231		goto badframe;
232	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
233		goto badframe;
234
235	sigdelsetmask(&set, ~_BLOCKABLE);
236	spin_lock_irq(&current->sighand->siglock);
237	current->blocked = set;
238	recalc_sigpending();
239	spin_unlock_irq(&current->sighand->siglock);
240
241	if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
242		goto badframe;
243
244	if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
245		goto badframe;
246
247	return gr8;
248
249badframe:
250	force_sig(SIGSEGV, current);
251	return 0;
252}
253
254/*
255 * Set up a signal frame
256 */
257static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
258{
259	save_user_regs(current->thread.user);
260
261	if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
262		goto badframe;
263
264	/* non-iBCS2 extensions.. */
265	if (__put_user(mask, &sc->sc_oldmask) < 0)
266		goto badframe;
267
268	return 0;
269
270 badframe:
271	return 1;
272}
273
274/*****************************************************************************/
275/*
276 * Determine which stack to use..
277 */
278static inline void __user *get_sigframe(struct k_sigaction *ka,
279					struct pt_regs *regs,
280					size_t frame_size)
281{
282	unsigned long sp;
283
284	/* Default to using normal stack */
285	sp = regs->sp;
286
287	/* This is the X/Open sanctioned signal stack switching.  */
288	if (ka->sa.sa_flags & SA_ONSTACK) {
289		if (! on_sig_stack(sp))
290			sp = current->sas_ss_sp + current->sas_ss_size;
291	}
292
293	return (void __user *) ((sp - frame_size) & ~7UL);
294} /* end get_sigframe() */
295
296/*****************************************************************************/
297/*
298 *
299 */
300static void setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs * regs)
301{
302	struct sigframe __user *frame;
303	int rsig;
304
305	frame = get_sigframe(ka, regs, sizeof(*frame));
306
307	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
308		goto give_sigsegv;
309
310	rsig = sig;
311	if (sig < 32 &&
312	    __current_thread_info->exec_domain &&
313	    __current_thread_info->exec_domain->signal_invmap)
314		rsig = __current_thread_info->exec_domain->signal_invmap[sig];
315
316	if (__put_user(rsig, &frame->sig) < 0)
317		goto give_sigsegv;
318
319	if (setup_sigcontext(&frame->sc, set->sig[0]))
320		goto give_sigsegv;
321
322	if (_NSIG_WORDS > 1) {
323		if (__copy_to_user(frame->extramask, &set->sig[1],
324				   sizeof(frame->extramask)))
325			goto give_sigsegv;
326	}
327
328	/* Set up to return from userspace.  If provided, use a stub
329	 * already in userspace.  */
330	if (ka->sa.sa_flags & SA_RESTORER) {
331		if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
332			goto give_sigsegv;
333	}
334	else {
335		/* Set up the following code on the stack:
336		 *	setlos	#__NR_sigreturn,gr7
337		 *	tira	gr0,0
338		 */
339		if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
340		    __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
341		    __put_user(0xc0700000, &frame->retcode[1]))
342			goto give_sigsegv;
343
344		flush_icache_range((unsigned long) frame->retcode,
345				   (unsigned long) (frame->retcode + 2));
346	}
347
348	/* set up registers for signal handler */
349	regs->sp   = (unsigned long) frame;
350	regs->lr   = (unsigned long) &frame->retcode;
351	regs->gr8  = sig;
352
353	if (get_personality & FDPIC_FUNCPTRS) {
354		struct fdpic_func_descriptor __user *funcptr =
355			(struct fdpic_func_descriptor *) ka->sa.sa_handler;
356		__get_user(regs->pc, &funcptr->text);
357		__get_user(regs->gr15, &funcptr->GOT);
358	} else {
359		regs->pc   = (unsigned long) ka->sa.sa_handler;
360		regs->gr15 = 0;
361	}
362
363	set_fs(USER_DS);
364
365#if DEBUG_SIG
366	printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
367		sig, current->comm, current->pid, frame, regs->pc, frame->pretcode);
368#endif
369
370	return;
371
372give_sigsegv:
373	if (sig == SIGSEGV)
374		ka->sa.sa_handler = SIG_DFL;
375
376	force_sig(SIGSEGV, current);
377} /* end setup_frame() */
378
379/*****************************************************************************/
380/*
381 *
382 */
383static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
384			   sigset_t *set, struct pt_regs * regs)
385{
386	struct rt_sigframe __user *frame;
387	int rsig;
388
389	frame = get_sigframe(ka, regs, sizeof(*frame));
390
391	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
392		goto give_sigsegv;
393
394	rsig = sig;
395	if (sig < 32 &&
396	    __current_thread_info->exec_domain &&
397	    __current_thread_info->exec_domain->signal_invmap)
398		rsig = __current_thread_info->exec_domain->signal_invmap[sig];
399
400	if (__put_user(rsig,		&frame->sig) ||
401	    __put_user(&frame->info,	&frame->pinfo) ||
402	    __put_user(&frame->uc,	&frame->puc))
403		goto give_sigsegv;
404
405	if (copy_siginfo_to_user(&frame->info, info))
406		goto give_sigsegv;
407
408	/* Create the ucontext.  */
409	if (__put_user(0, &frame->uc.uc_flags) ||
410	    __put_user(0, &frame->uc.uc_link) ||
411	    __put_user((void*)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
412	    __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
413	    __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
414		goto give_sigsegv;
415
416	if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
417		goto give_sigsegv;
418
419	if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
420		goto give_sigsegv;
421
422	/* Set up to return from userspace.  If provided, use a stub
423	 * already in userspace.  */
424	if (ka->sa.sa_flags & SA_RESTORER) {
425		if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
426			goto give_sigsegv;
427	}
428	else {
429		/* Set up the following code on the stack:
430		 *	setlos	#__NR_sigreturn,gr7
431		 *	tira	gr0,0
432		 */
433		if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
434		    __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
435		    __put_user(0xc0700000, &frame->retcode[1]))
436			goto give_sigsegv;
437
438		flush_icache_range((unsigned long) frame->retcode,
439				   (unsigned long) (frame->retcode + 2));
440	}
441
442	/* Set up registers for signal handler */
443	regs->sp  = (unsigned long) frame;
444	regs->lr   = (unsigned long) &frame->retcode;
445	regs->gr8 = sig;
446	regs->gr9 = (unsigned long) &frame->info;
447
448	if (get_personality & FDPIC_FUNCPTRS) {
449		struct fdpic_func_descriptor *funcptr =
450			(struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
451		__get_user(regs->pc, &funcptr->text);
452		__get_user(regs->gr15, &funcptr->GOT);
453	} else {
454		regs->pc   = (unsigned long) ka->sa.sa_handler;
455		regs->gr15 = 0;
456	}
457
458	set_fs(USER_DS);
459
460#if DEBUG_SIG
461	printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
462		sig, current->comm, current->pid, frame, regs->pc, frame->pretcode);
463#endif
464
465	return;
466
467give_sigsegv:
468	if (sig == SIGSEGV)
469		ka->sa.sa_handler = SIG_DFL;
470	force_sig(SIGSEGV, current);
471
472} /* end setup_rt_frame() */
473
474/*****************************************************************************/
475/*
476 * OK, we're invoking a handler
477 */
478static void handle_signal(unsigned long sig, siginfo_t *info,
479			  struct k_sigaction *ka, sigset_t *oldset,
480			  struct pt_regs *regs)
481{
482	/* Are we from a system call? */
483	if (in_syscall(regs)) {
484		/* If so, check system call restarting.. */
485		switch (regs->gr8) {
486		case -ERESTART_RESTARTBLOCK:
487		case -ERESTARTNOHAND:
488			regs->gr8 = -EINTR;
489			break;
490
491		case -ERESTARTSYS:
492			if (!(ka->sa.sa_flags & SA_RESTART)) {
493				regs->gr8 = -EINTR;
494				break;
495			}
496			/* fallthrough */
497		case -ERESTARTNOINTR:
498			regs->gr8 = regs->orig_gr8;
499			regs->pc -= 4;
500		}
501	}
502
503	/* Set up the stack frame */
504	if (ka->sa.sa_flags & SA_SIGINFO)
505		setup_rt_frame(sig, ka, info, oldset, regs);
506	else
507		setup_frame(sig, ka, oldset, regs);
508
509	if (!(ka->sa.sa_flags & SA_NODEFER)) {
510		spin_lock_irq(&current->sighand->siglock);
511		sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
512		sigaddset(&current->blocked, sig);
513		recalc_sigpending();
514		spin_unlock_irq(&current->sighand->siglock);
515	}
516} /* end handle_signal() */
517
518/*****************************************************************************/
519/*
520 * Note that 'init' is a special process: it doesn't get signals it doesn't
521 * want to handle. Thus you cannot kill init even with a SIGKILL even by
522 * mistake.
523 */
524int do_signal(struct pt_regs *regs, sigset_t *oldset)
525{
526	struct k_sigaction ka;
527	siginfo_t info;
528	int signr;
529
530	/*
531	 * We want the common case to go fast, which
532	 * is why we may in certain cases get here from
533	 * kernel mode. Just return without doing anything
534	 * if so.
535	 */
536	if (!user_mode(regs))
537		return 1;
538
539	if (current->flags & PF_FREEZE) {
540		refrigerator(0);
541		goto no_signal;
542	}
543
544	if (!oldset)
545		oldset = &current->blocked;
546
547	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
548	if (signr > 0) {
549		handle_signal(signr, &info, &ka, oldset, regs);
550		return 1;
551	}
552
553 no_signal:
554	/* Did we come from a system call? */
555	if (regs->syscallno >= 0) {
556		/* Restart the system call - no handlers present */
557		if (regs->gr8 == -ERESTARTNOHAND ||
558		    regs->gr8 == -ERESTARTSYS ||
559		    regs->gr8 == -ERESTARTNOINTR) {
560			regs->gr8 = regs->orig_gr8;
561			regs->pc -= 4;
562		}
563
564		if (regs->gr8 == -ERESTART_RESTARTBLOCK){
565			regs->gr8 = __NR_restart_syscall;
566			regs->pc -= 4;
567		}
568	}
569
570	return 0;
571} /* end do_signal() */
572
573/*****************************************************************************/
574/*
575 * notification of userspace execution resumption
576 * - triggered by current->work.notify_resume
577 */
578asmlinkage void do_notify_resume(__u32 thread_info_flags)
579{
580	/* pending single-step? */
581	if (thread_info_flags & _TIF_SINGLESTEP)
582		clear_thread_flag(TIF_SINGLESTEP);
583
584	/* deal with pending signal delivery */
585	if (thread_info_flags & _TIF_SIGPENDING)
586		do_signal(__frame, NULL);
587
588} /* end do_notify_resume() */