arch/blackfin/kernel/signal.c - maze/linux - Git at Google

 /*
  * File:         arch/blackfin/kernel/signal.c
  * Based on:
  * Author:
  *
  * Created:
  * Description:
  *
  * Modified:
  *               Copyright 2004-2006 Analog Devices Inc.
  *
  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see the file COPYING, or write
  * to the Free Software Foundation, Inc.,
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */

 #include <linux/signal.h>
 #include <linux/syscalls.h>
 #include <linux/ptrace.h>
 #include <linux/tty.h>
 #include <linux/personality.h>
 #include <linux/binfmts.h>
 #include <linux/freezer.h>
 #include <linux/uaccess.h>

 #include <asm/cacheflush.h>
 #include <asm/ucontext.h>
 #include <asm/fixed_code.h>

 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

 /* Location of the trace bit in SYSCFG. */
 #define TRACE_BITS 0x0001

 struct fdpic_func_descriptor {
 	unsigned long	text;
 	unsigned long	GOT;
 };

 struct rt_sigframe {
 	int sig;
 	struct siginfo *pinfo;
 	void *puc;
 	/* This is no longer needed by the kernel, but unfortunately userspace
 	 * code expects it to be there.  */
 	char retcode[8];
 	struct siginfo info;
 	struct ucontext uc;
 };

 asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 {
 	return do_sigaltstack(uss, uoss, rdusp());
 }

 static inline int
 rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *pr0)
 {
 	unsigned long usp = 0;
 	int err = 0;

 #define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)

 	/* restore passed registers */
 	RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
 	RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
 	RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
 	RESTORE(p4); RESTORE(p5);
 	err |= __get_user(usp, &sc->sc_usp);
 	wrusp(usp);
 	RESTORE(a0w); RESTORE(a1w);
 	RESTORE(a0x); RESTORE(a1x);
 	RESTORE(astat);
 	RESTORE(rets);
 	RESTORE(pc);
 	RESTORE(retx);
 	RESTORE(fp);
 	RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
 	RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
 	RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
 	RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
 	RESTORE(lc0); RESTORE(lc1);
 	RESTORE(lt0); RESTORE(lt1);
 	RESTORE(lb0); RESTORE(lb1);
 	RESTORE(seqstat);

 	regs->orig_p0 = -1;	/* disable syscall checks */

 	*pr0 = regs->r0;
 	return err;
 }

 asmlinkage int do_rt_sigreturn(unsigned long __unused)
 {
 	struct pt_regs *regs = (struct pt_regs *)__unused;
 	unsigned long usp = rdusp();
 	struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
 	sigset_t set;
 	int r0;

 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 		goto badframe;
 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 		goto badframe;

 	sigdelsetmask(&set, ~_BLOCKABLE);
 	spin_lock_irq(&current->sighand->siglock);
 	current->blocked = set;
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);

 	if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 		goto badframe;

 	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
 		goto badframe;

 	return r0;

  badframe:
 	force_sig(SIGSEGV, current);
 	return 0;
 }

 static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
 {
 	int err = 0;

 #define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)

 	SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
 	SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
 	SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
 	SETUP(p4); SETUP(p5);
 	err |= __put_user(rdusp(), &sc->sc_usp);
 	SETUP(a0w); SETUP(a1w);
 	SETUP(a0x); SETUP(a1x);
 	SETUP(astat);
 	SETUP(rets);
 	SETUP(pc);
 	SETUP(retx);
 	SETUP(fp);
 	SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
 	SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
 	SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
 	SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
 	SETUP(lc0); SETUP(lc1);
 	SETUP(lt0); SETUP(lt1);
 	SETUP(lb0); SETUP(lb1);
 	SETUP(seqstat);

 	return err;
 }

 static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 				 size_t frame_size)
 {
 	unsigned long usp;

 	/* Default to using normal stack.  */
 	usp = rdusp();

 	/* This is the X/Open sanctioned signal stack switching.  */
 	if (ka->sa.sa_flags & SA_ONSTACK) {
 		if (!on_sig_stack(usp))
 			usp = current->sas_ss_sp + current->sas_ss_size;
 	}
 	return (void *)((usp - frame_size) & -8UL);
 }

 static int
 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 	       sigset_t * set, struct pt_regs *regs)
 {
 	struct rt_sigframe *frame;
 	int err = 0;

 	frame = get_sigframe(ka, regs, sizeof(*frame));

 	err |= __put_user((current_thread_info()->exec_domain
 			   && current_thread_info()->exec_domain->signal_invmap
 			   && sig < 32
 			   ? current_thread_info()->exec_domain->
 			   signal_invmap[sig] : sig), &frame->sig);

 	err |= __put_user(&frame->info, &frame->pinfo);
 	err |= __put_user(&frame->uc, &frame->puc);
 	err |= copy_siginfo_to_user(&frame->info, info);

 	/* Create the ucontext.  */
 	err |= __put_user(0, &frame->uc.uc_flags);
 	err |= __put_user(0, &frame->uc.uc_link);
 	err |=
 	    __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 	err |= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
 	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 	err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
 	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

 	if (err)
 		goto give_sigsegv;

 	/* Set up registers for signal handler */
 	wrusp((unsigned long)frame);
 	if (current->personality & FDPIC_FUNCPTRS) {
 		struct fdpic_func_descriptor __user *funcptr =
 			(struct fdpic_func_descriptor *) ka->sa.sa_handler;
 		__get_user(regs->pc, &funcptr->text);
 		__get_user(regs->p3, &funcptr->GOT);
 	} else
 		regs->pc = (unsigned long)ka->sa.sa_handler;
 	regs->rets = SIGRETURN_STUB;

 	regs->r0 = frame->sig;
 	regs->r1 = (unsigned long)(&frame->info);
 	regs->r2 = (unsigned long)(&frame->uc);

 	/*
 	 * Clear the trace flag when entering the signal handler, but
 	 * notify any tracer that was single-stepping it. The tracer
 	 * may want to single-step inside the handler too.
 	 */
 	if (regs->syscfg & TRACE_BITS) {
 		regs->syscfg &= ~TRACE_BITS;
 		ptrace_notify(SIGTRAP);
 	}

 	return 0;

  give_sigsegv:
 	if (sig == SIGSEGV)
 		ka->sa.sa_handler = SIG_DFL;
 	force_sig(SIGSEGV, current);
 	return -EFAULT;
 }

 static inline void
 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 {
 	switch (regs->r0) {
 	case -ERESTARTNOHAND:
 		if (!has_handler)
 			goto do_restart;
 		regs->r0 = -EINTR;
 		break;

 	case -ERESTARTSYS:
 		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 			regs->r0 = -EINTR;
 			break;
 		}
 		/* fallthrough */
 	case -ERESTARTNOINTR:
  do_restart:
 		regs->p0 = regs->orig_p0;
 		regs->r0 = regs->orig_r0;
 		regs->pc -= 2;
 		break;
 	}
 }

 /*
  * OK, we're invoking a handler
  */
 static int
 handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
 	      sigset_t *oldset, struct pt_regs *regs)
 {
 	int ret;

 	/* are we from a system call? to see pt_regs->orig_p0 */
 	if (regs->orig_p0 >= 0)
 		/* If so, check system call restarting.. */
 		handle_restart(regs, ka, 1);

 	/* set up the stack frame */
 	ret = setup_rt_frame(sig, ka, info, oldset, regs);

 	if (ret == 0) {
 		spin_lock_irq(&current->sighand->siglock);
 		sigorsets(&current->blocked, &current->blocked,
 			  &ka->sa.sa_mask);
 		if (!(ka->sa.sa_flags & SA_NODEFER))
 			sigaddset(&current->blocked, sig);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
 	}
 	return ret;
 }

 /*
  * Note that 'init' is a special process: it doesn't get signals it doesn't
  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  * mistake.
  *
  * Note that we go through the signals twice: once to check the signals
  * that the kernel can handle, and then we build all the user-level signal
  * handling stack-frames in one go after that.
  */
 asmlinkage void do_signal(struct pt_regs *regs)
 {
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;
 	sigset_t *oldset;

 	current->thread.esp0 = (unsigned long)regs;

 	if (try_to_freeze())
 		goto no_signal;

 	if (test_thread_flag(TIF_RESTORE_SIGMASK))
 		oldset = &current->saved_sigmask;
 	else
 		oldset = &current->blocked;

 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
 		/* Whee!  Actually deliver the signal.  */
 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 			/* a signal was successfully delivered; the saved
 			 * sigmask will have been stored in the signal frame,
 			 * and will be restored by sigreturn, so we can simply
 			 * clear the TIF_RESTORE_SIGMASK flag */
 			if (test_thread_flag(TIF_RESTORE_SIGMASK))
 				clear_thread_flag(TIF_RESTORE_SIGMASK);
 		}

 		return;
 	}

  no_signal:
 	/* Did we come from a system call? */
 	if (regs->orig_p0 >= 0)
 		/* Restart the system call - no handlers present */
 		handle_restart(regs, NULL, 0);

 	/* if there's no signal to deliver, we just put the saved sigmask
 	 * back */
 	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 		clear_thread_flag(TIF_RESTORE_SIGMASK);
 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 	}
 }
	/*
	* File: arch/blackfin/kernel/signal.c
	* Based on:
	* Author:
	*
	* Created:
	* Description:
	*
	* Modified:
	* Copyright 2004-2006 Analog Devices Inc.
	*
	* Bugs: Enter bugs at http://blackfin.uclinux.org/
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see the file COPYING, or write
	* to the Free Software Foundation, Inc.,
	* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#include <linux/signal.h>
	#include <linux/syscalls.h>
	#include <linux/ptrace.h>
	#include <linux/tty.h>
	#include <linux/personality.h>
	#include <linux/binfmts.h>
	#include <linux/freezer.h>
	#include <linux/uaccess.h>

	#include <asm/cacheflush.h>
	#include <asm/ucontext.h>
	#include <asm/fixed_code.h>

	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))

	/* Location of the trace bit in SYSCFG. */
	#define TRACE_BITS 0x0001

	struct fdpic_func_descriptor {
	unsigned long text;
	unsigned long GOT;
	};

	struct rt_sigframe {
	int sig;
	struct siginfo *pinfo;
	void *puc;
	/* This is no longer needed by the kernel, but unfortunately userspace
	* code expects it to be there. */
	char retcode[8];
	struct siginfo info;
	struct ucontext uc;
	};

	asmlinkage int sys_sigaltstack(const stack_t __user uss, stack_t __user uoss)
	{
	return do_sigaltstack(uss, uoss, rdusp());
	}

	static inline int
	rt_restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc, int *pr0)
	{
	unsigned long usp = 0;
	int err = 0;

	#define RESTORE(x) err \|= __get_user(regs->x, &sc->sc_##x)

	/* restore passed registers */
	RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
	RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
	RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
	RESTORE(p4); RESTORE(p5);
	err \|= __get_user(usp, &sc->sc_usp);
	wrusp(usp);
	RESTORE(a0w); RESTORE(a1w);
	RESTORE(a0x); RESTORE(a1x);
	RESTORE(astat);
	RESTORE(rets);
	RESTORE(pc);
	RESTORE(retx);
	RESTORE(fp);
	RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
	RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
	RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
	RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
	RESTORE(lc0); RESTORE(lc1);
	RESTORE(lt0); RESTORE(lt1);
	RESTORE(lb0); RESTORE(lb1);
	RESTORE(seqstat);

	regs->orig_p0 = -1; /* disable syscall checks */

	*pr0 = regs->r0;
	return err;
	}

	asmlinkage int do_rt_sigreturn(unsigned long __unused)
	{
	struct pt_regs regs = (struct pt_regs )__unused;
	unsigned long usp = rdusp();
	struct rt_sigframe frame = (struct rt_sigframe )(usp);
	sigset_t set;
	int r0;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
	goto badframe;

	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
	goto badframe;

	return r0;

	badframe:
	force_sig(SIGSEGV, current);
	return 0;
	}

	static inline int rt_setup_sigcontext(struct sigcontext sc, struct pt_regs regs)
	{
	int err = 0;

	#define SETUP(x) err \|= __put_user(regs->x, &sc->sc_##x)

	SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
	SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
	SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
	SETUP(p4); SETUP(p5);
	err \|= __put_user(rdusp(), &sc->sc_usp);
	SETUP(a0w); SETUP(a1w);
	SETUP(a0x); SETUP(a1x);
	SETUP(astat);
	SETUP(rets);
	SETUP(pc);
	SETUP(retx);
	SETUP(fp);
	SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
	SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
	SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
	SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
	SETUP(lc0); SETUP(lc1);
	SETUP(lt0); SETUP(lt1);
	SETUP(lb0); SETUP(lb1);
	SETUP(seqstat);

	return err;
	}

	static inline void get_sigframe(struct k_sigaction ka, struct pt_regs *regs,
	size_t frame_size)
	{
	unsigned long usp;

	/* Default to using normal stack. */
	usp = rdusp();

	/* This is the X/Open sanctioned signal stack switching. */
	if (ka->sa.sa_flags & SA_ONSTACK) {
	if (!on_sig_stack(usp))
	usp = current->sas_ss_sp + current->sas_ss_size;
	}
	return (void *)((usp - frame_size) & -8UL);
	}

	static int
	setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	sigset_t * set, struct pt_regs *regs)
	{
	struct rt_sigframe *frame;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));

	err \|= __put_user((current_thread_info()->exec_domain
	&& current_thread_info()->exec_domain->signal_invmap
	&& sig < 32
	? current_thread_info()->exec_domain->
	signal_invmap[sig] : sig), &frame->sig);

	err \|= __put_user(&frame->info, &frame->pinfo);
	err \|= __put_user(&frame->uc, &frame->puc);
	err \|= copy_siginfo_to_user(&frame->info, info);

	/* Create the ucontext. */
	err \|= __put_user(0, &frame->uc.uc_flags);
	err \|= __put_user(0, &frame->uc.uc_link);
	err \|=
	__put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err \|= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err \|= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
	err \|= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
	goto give_sigsegv;

	/* Set up registers for signal handler */
	wrusp((unsigned long)frame);
	if (current->personality & FDPIC_FUNCPTRS) {
	struct fdpic_func_descriptor __user *funcptr =
	(struct fdpic_func_descriptor *) ka->sa.sa_handler;
	__get_user(regs->pc, &funcptr->text);
	__get_user(regs->p3, &funcptr->GOT);
	} else
	regs->pc = (unsigned long)ka->sa.sa_handler;
	regs->rets = SIGRETURN_STUB;

	regs->r0 = frame->sig;
	regs->r1 = (unsigned long)(&frame->info);
	regs->r2 = (unsigned long)(&frame->uc);

	/*
	* Clear the trace flag when entering the signal handler, but
	* notify any tracer that was single-stepping it. The tracer
	* may want to single-step inside the handler too.
	*/
	if (regs->syscfg & TRACE_BITS) {
	regs->syscfg &= ~TRACE_BITS;
	ptrace_notify(SIGTRAP);
	}

	return 0;

	give_sigsegv:
	if (sig == SIGSEGV)
	ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
	return -EFAULT;
	}

	static inline void
	handle_restart(struct pt_regs regs, struct k_sigaction ka, int has_handler)
	{
	switch (regs->r0) {
	case -ERESTARTNOHAND:
	if (!has_handler)
	goto do_restart;
	regs->r0 = -EINTR;
	break;

	case -ERESTARTSYS:
	if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
	regs->r0 = -EINTR;
	break;
	}
	/* fallthrough */
	case -ERESTARTNOINTR:
	do_restart:
	regs->p0 = regs->orig_p0;
	regs->r0 = regs->orig_r0;
	regs->pc -= 2;
	break;
	}
	}

	/*
	* OK, we're invoking a handler
	*/
	static int
	handle_signal(int sig, siginfo_t info, struct k_sigaction ka,
	sigset_t oldset, struct pt_regs regs)
	{
	int ret;

	/* are we from a system call? to see pt_regs->orig_p0 */
	if (regs->orig_p0 >= 0)
	/* If so, check system call restarting.. */
	handle_restart(regs, ka, 1);

	/* set up the stack frame */
	ret = setup_rt_frame(sig, ka, info, oldset, regs);

	if (ret == 0) {
	spin_lock_irq(&current->sighand->siglock);
	sigorsets(&current->blocked, &current->blocked,
	&ka->sa.sa_mask);
	if (!(ka->sa.sa_flags & SA_NODEFER))
	sigaddset(&current->blocked, sig);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	}
	return ret;
	}

	/*
	* Note that 'init' is a special process: it doesn't get signals it doesn't
	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	* mistake.
	*
	* Note that we go through the signals twice: once to check the signals
	* that the kernel can handle, and then we build all the user-level signal
	* handling stack-frames in one go after that.
	*/
	asmlinkage void do_signal(struct pt_regs *regs)
	{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	sigset_t *oldset;

	current->thread.esp0 = (unsigned long)regs;

	if (try_to_freeze())
	goto no_signal;

	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	oldset = &current->saved_sigmask;
	else
	oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
	/* Whee! Actually deliver the signal. */
	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
	/* a signal was successfully delivered; the saved
	* sigmask will have been stored in the signal frame,
	* and will be restored by sigreturn, so we can simply
	* clear the TIF_RESTORE_SIGMASK flag */
	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	clear_thread_flag(TIF_RESTORE_SIGMASK);
	}

	return;
	}

	no_signal:
	/* Did we come from a system call? */
	if (regs->orig_p0 >= 0)
	/* Restart the system call - no handlers present */
	handle_restart(regs, NULL, 0);

	/* if there's no signal to deliver, we just put the saved sigmask
	* back */
	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	clear_thread_flag(TIF_RESTORE_SIGMASK);
	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}
	}