/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * arch/sh64/kernel/signal.c
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003  Paul Mundt
 * Copyright (C) 2004  Richard Curnow
 *
 * Started from sh version.
 *
 */
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/personality.h>
#include <linux/freezer.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>


#define REG_RET 9
#define REG_ARG1 2
#define REG_ARG2 3
#define REG_ARG3 4
#define REG_SP 15
#define REG_PR 18
#define REF_REG_RET regs->regs[REG_RET]
#define REF_REG_SP regs->regs[REG_SP]
#define DEREF_REG_PR regs->regs[REG_PR]

#define DEBUG_SIG 0

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

asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */

asmlinkage int
sys_sigsuspend(old_sigset_t mask,
	       unsigned long r3, unsigned long r4, unsigned long r5,
	       unsigned long r6, unsigned long r7,
	       struct pt_regs * regs)
{
	sigset_t saveset;

	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	REF_REG_RET = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		regs->pc += 4;    /* because sys_sigreturn decrements the pc */
		if (do_signal(regs, &saveset)) {
			/* pc now points at signal handler. Need to decrement
			   it because entry.S will increment it. */
			regs->pc -= 4;
			return -EINTR;
		}
	}
}

asmlinkage int
sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
	          unsigned long r4, unsigned long r5, unsigned long r6,
	          unsigned long r7,
	          struct pt_regs * regs)
{
	sigset_t saveset, newset;

	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	if (copy_from_user(&newset, unewset, sizeof(newset)))
		return -EFAULT;
	sigdelsetmask(&newset, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	REF_REG_RET = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		regs->pc += 4;    /* because sys_sigreturn decrements the pc */
		if (do_signal(regs, &saveset)) {
			/* pc now points at signal handler. Need to decrement
			   it because entry.S will increment it. */
			regs->pc -= 4;
			return -EINTR;
		}
	}
}

asmlinkage int
sys_sigaction(int sig, const struct old_sigaction __user *act,
	      struct old_sigaction __user *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	if (act) {
		old_sigset_t mask;
		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
			return -EFAULT;
		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
		__get_user(mask, &act->sa_mask);
		siginitset(&new_ka.sa.sa_mask, mask);
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
			return -EFAULT;
		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	}

	return ret;
}

asmlinkage int
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
	        unsigned long r4, unsigned long r5, unsigned long r6,
	        unsigned long r7,
	        struct pt_regs * regs)
{
	return do_sigaltstack(uss, uoss, REF_REG_SP);
}


/*
 * Do a signal return; undo the signal stack.
 */

struct sigframe
{
	struct sigcontext sc;
	unsigned long extramask[_NSIG_WORDS-1];
	long long retcode[2];
};

struct rt_sigframe
{
	struct siginfo __user *pinfo;
	void *puc;
	struct siginfo info;
	struct ucontext uc;
	long long retcode[2];
};

#ifdef CONFIG_SH_FPU
static inline int
restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
{
	int err = 0;
	int fpvalid;

	err |= __get_user (fpvalid, &sc->sc_fpvalid);
	conditional_used_math(fpvalid);
	if (! fpvalid)
		return err;

	if (current == last_task_used_math) {
		last_task_used_math = NULL;
		regs->sr |= SR_FD;
	}

	err |= __copy_from_user(&current->thread.fpu.hard, &sc->sc_fpregs[0],
				(sizeof(long long) * 32) + (sizeof(int) * 1));

	return err;
}

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

	fpvalid = !!used_math();
	err |= __put_user(fpvalid, &sc->sc_fpvalid);
	if (! fpvalid)
		return err;

	if (current == last_task_used_math) {
		grab_fpu();
		fpsave(&current->thread.fpu.hard);
		release_fpu();
		last_task_used_math = NULL;
		regs->sr |= SR_FD;
	}

	err |= __copy_to_user(&sc->sc_fpregs[0], &current->thread.fpu.hard,
			      (sizeof(long long) * 32) + (sizeof(int) * 1));
	clear_used_math();

	return err;
}
#else
static inline int
restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
{}
static inline int
setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
{}
#endif

static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, long long *r2_p)
{
	unsigned int err = 0;
        unsigned long long current_sr, new_sr;
#define SR_MASK 0xffff8cfd

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

	COPY(regs[0]);	COPY(regs[1]);	COPY(regs[2]);	COPY(regs[3]);
	COPY(regs[4]);	COPY(regs[5]);	COPY(regs[6]);	COPY(regs[7]);
	COPY(regs[8]);	COPY(regs[9]);  COPY(regs[10]);	COPY(regs[11]);
	COPY(regs[12]);	COPY(regs[13]);	COPY(regs[14]);	COPY(regs[15]);
	COPY(regs[16]);	COPY(regs[17]);	COPY(regs[18]);	COPY(regs[19]);
	COPY(regs[20]);	COPY(regs[21]);	COPY(regs[22]);	COPY(regs[23]);
	COPY(regs[24]);	COPY(regs[25]);	COPY(regs[26]);	COPY(regs[27]);
	COPY(regs[28]);	COPY(regs[29]);	COPY(regs[30]);	COPY(regs[31]);
	COPY(regs[32]);	COPY(regs[33]);	COPY(regs[34]);	COPY(regs[35]);
	COPY(regs[36]);	COPY(regs[37]);	COPY(regs[38]);	COPY(regs[39]);
	COPY(regs[40]);	COPY(regs[41]);	COPY(regs[42]);	COPY(regs[43]);
	COPY(regs[44]);	COPY(regs[45]);	COPY(regs[46]);	COPY(regs[47]);
	COPY(regs[48]);	COPY(regs[49]);	COPY(regs[50]);	COPY(regs[51]);
	COPY(regs[52]);	COPY(regs[53]);	COPY(regs[54]);	COPY(regs[55]);
	COPY(regs[56]);	COPY(regs[57]);	COPY(regs[58]);	COPY(regs[59]);
	COPY(regs[60]);	COPY(regs[61]);	COPY(regs[62]);
	COPY(tregs[0]);	COPY(tregs[1]);	COPY(tregs[2]);	COPY(tregs[3]);
	COPY(tregs[4]);	COPY(tregs[5]);	COPY(tregs[6]);	COPY(tregs[7]);

        /* Prevent the signal handler manipulating SR in a way that can
           crash the kernel. i.e. only allow S, Q, M, PR, SZ, FR to be
           modified */
        current_sr = regs->sr;
        err |= __get_user(new_sr, &sc->sc_sr);
        regs->sr &= SR_MASK;
        regs->sr |= (new_sr & ~SR_MASK);

	COPY(pc);

#undef COPY

	/* Must do this last in case it sets regs->sr.fd (i.e. after rest of sr
	 * has been restored above.) */
	err |= restore_sigcontext_fpu(regs, sc);

	regs->syscall_nr = -1;		/* disable syscall checks */
	err |= __get_user(*r2_p, &sc->sc_regs[REG_RET]);
	return err;
}

asmlinkage int sys_sigreturn(unsigned long r2, unsigned long r3,
				   unsigned long r4, unsigned long r5,
				   unsigned long r6, unsigned long r7,
				   struct pt_regs * regs)
{
	struct sigframe __user *frame = (struct sigframe __user *) (long) REF_REG_SP;
	sigset_t set;
	long long ret;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;

	if (__get_user(set.sig[0], &frame->sc.oldmask)
	    || (_NSIG_WORDS > 1
		&& __copy_from_user(&set.sig[1], &frame->extramask,
				    sizeof(frame->extramask))))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);

	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext(regs, &frame->sc, &ret))
		goto badframe;
	regs->pc -= 4;

	return (int) ret;

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

asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3,
				unsigned long r4, unsigned long r5,
				unsigned long r6, unsigned long r7,
				struct pt_regs * regs)
{
	struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (long) REF_REG_SP;
	sigset_t set;
	stack_t __user st;
	long long ret;

	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 (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ret))
		goto badframe;
	regs->pc -= 4;

	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
		goto badframe;
	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	do_sigaltstack(&st, NULL, REF_REG_SP);

	return (int) ret;

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

/*
 * Set up a signal frame.
 */

static int
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
		 unsigned long mask)
{
	int err = 0;

	/* Do this first, otherwise is this sets sr->fd, that value isn't preserved. */
	err |= setup_sigcontext_fpu(regs, sc);

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

	COPY(regs[0]);	COPY(regs[1]);	COPY(regs[2]);	COPY(regs[3]);
	COPY(regs[4]);	COPY(regs[5]);	COPY(regs[6]);	COPY(regs[7]);
	COPY(regs[8]);	COPY(regs[9]);	COPY(regs[10]);	COPY(regs[11]);
	COPY(regs[12]);	COPY(regs[13]);	COPY(regs[14]);	COPY(regs[15]);
	COPY(regs[16]);	COPY(regs[17]);	COPY(regs[18]);	COPY(regs[19]);
	COPY(regs[20]);	COPY(regs[21]);	COPY(regs[22]);	COPY(regs[23]);
	COPY(regs[24]);	COPY(regs[25]);	COPY(regs[26]);	COPY(regs[27]);
	COPY(regs[28]);	COPY(regs[29]);	COPY(regs[30]);	COPY(regs[31]);
	COPY(regs[32]);	COPY(regs[33]);	COPY(regs[34]);	COPY(regs[35]);
	COPY(regs[36]);	COPY(regs[37]);	COPY(regs[38]);	COPY(regs[39]);
	COPY(regs[40]);	COPY(regs[41]);	COPY(regs[42]);	COPY(regs[43]);
	COPY(regs[44]);	COPY(regs[45]);	COPY(regs[46]);	COPY(regs[47]);
	COPY(regs[48]);	COPY(regs[49]);	COPY(regs[50]);	COPY(regs[51]);
	COPY(regs[52]);	COPY(regs[53]);	COPY(regs[54]);	COPY(regs[55]);
	COPY(regs[56]);	COPY(regs[57]);	COPY(regs[58]);	COPY(regs[59]);
	COPY(regs[60]);	COPY(regs[61]);	COPY(regs[62]);
	COPY(tregs[0]);	COPY(tregs[1]);	COPY(tregs[2]);	COPY(tregs[3]);
	COPY(tregs[4]);	COPY(tregs[5]);	COPY(tregs[6]);	COPY(tregs[7]);
	COPY(sr);	COPY(pc);

#undef COPY

	err |= __put_user(mask, &sc->oldmask);

	return err;
}

/*
 * Determine which stack to use..
 */
static inline void __user *
get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
{
	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
		sp = current->sas_ss_sp + current->sas_ss_size;

	return (void __user *)((sp - frame_size) & -8ul);
}

void sa_default_restorer(void);		/* See comments below */
void sa_default_rt_restorer(void);	/* See comments below */

static void setup_frame(int sig, struct k_sigaction *ka,
			sigset_t *set, struct pt_regs *regs)
{
	struct sigframe __user *frame;
	int err = 0;
	int signal;

	frame = get_sigframe(ka, regs->regs[REG_SP], sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	if (_NSIG_WORDS > 1) {
		err |= __copy_to_user(frame->extramask, &set->sig[1],
				      sizeof(frame->extramask)); }

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1;

		/*
		 * On SH5 all edited pointers are subject to NEFF
		 */
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
	} else {
		/*
		 * Different approach on SH5.
	         * . Endianness independent asm code gets placed in entry.S .
		 *   This is limited to four ASM instructions corresponding
		 *   to two long longs in size.
		 * . err checking is done on the else branch only
		 * . flush_icache_range() is called upon __put_user() only
		 * . all edited pointers are subject to NEFF
		 * . being code, linker turns ShMedia bit on, always
		 *   dereference index -1.
		 */
		DEREF_REG_PR = (unsigned long) frame->retcode | 0x01;
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;

		if (__copy_to_user(frame->retcode,
			(unsigned long long)sa_default_restorer & (~1), 16) != 0)
			goto give_sigsegv;

		/* Cohere the trampoline with the I-cache. */
		flush_cache_sigtramp(DEREF_REG_PR-1, DEREF_REG_PR-1+16);
	}

	/*
	 * Set up registers for signal handler.
	 * All edited pointers are subject to NEFF.
	 */
	regs->regs[REG_SP] = (unsigned long) frame;
	regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ?
        		 (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP];
	regs->regs[REG_ARG1] = signal; /* Arg for signal handler */


	regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
	regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->sc;

	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc;

	set_fs(USER_DS);

#if DEBUG_SIG
	/* Broken %016Lx */
	printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
		signal,
		current->comm, current->pid, frame,
		regs->pc >> 32, regs->pc & 0xffffffff,
		DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
#endif

	return;

give_sigsegv:
	force_sigsegv(sig, current);
}

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

	frame = get_sigframe(ka, regs->regs[REG_SP], sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

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

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* 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(regs->regs[REG_SP]),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext,
			        regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1;

		/*
		 * On SH5 all edited pointers are subject to NEFF
		 */
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
	} else {
		/*
		 * Different approach on SH5.
	         * . Endianness independent asm code gets placed in entry.S .
		 *   This is limited to four ASM instructions corresponding
		 *   to two long longs in size.
		 * . err checking is done on the else branch only
		 * . flush_icache_range() is called upon __put_user() only
		 * . all edited pointers are subject to NEFF
		 * . being code, linker turns ShMedia bit on, always
		 *   dereference index -1.
		 */

		DEREF_REG_PR = (unsigned long) frame->retcode | 0x01;
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;

		if (__copy_to_user(frame->retcode,
			(unsigned long long)sa_default_rt_restorer & (~1), 16) != 0)
			goto give_sigsegv;

		flush_icache_range(DEREF_REG_PR-1, DEREF_REG_PR-1+15);
	}

	/*
	 * Set up registers for signal handler.
	 * All edited pointers are subject to NEFF.
	 */
	regs->regs[REG_SP] = (unsigned long) frame;
	regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ?
        		 (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP];
	regs->regs[REG_ARG1] = signal; /* Arg for signal handler */
	regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->info;
	regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->uc.uc_mcontext;
	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc;

	set_fs(USER_DS);

#if DEBUG_SIG
	/* Broken %016Lx */
	printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
		signal,
		current->comm, current->pid, frame,
		regs->pc >> 32, regs->pc & 0xffffffff,
		DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
#endif

	return;

give_sigsegv:
	force_sigsegv(sig, current);
}

/*
 * OK, we're invoking a handler
 */

static void
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
		sigset_t *oldset, struct pt_regs * regs)
{
	/* Are we from a system call? */
	if (regs->syscall_nr >= 0) {
		/* If so, check system call restarting.. */
		switch (regs->regs[REG_RET]) {
			case -ERESTART_RESTARTBLOCK:
			case -ERESTARTNOHAND:
				regs->regs[REG_RET] = -EINTR;
				break;

			case -ERESTARTSYS:
				if (!(ka->sa.sa_flags & SA_RESTART)) {
					regs->regs[REG_RET] = -EINTR;
					break;
				}
			/* fallthrough */
			case -ERESTARTNOINTR:
				/* Decode syscall # */
				regs->regs[REG_RET] = regs->syscall_nr;
				regs->pc -= 4;
		}
	}

	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		setup_rt_frame(sig, ka, info, oldset, regs);
	else
		setup_frame(sig, ka, oldset, regs);

	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);
}

/*
 * 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.
 */
int do_signal(struct pt_regs *regs, sigset_t *oldset)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;

	/*
	 * We want the common case to go fast, which
	 * is why we may in certain cases get here from
	 * kernel mode. Just return without doing anything
	 * if so.
	 */
	if (!user_mode(regs))
		return 1;

	if (try_to_freeze())
		goto no_signal;

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

	signr = get_signal_to_deliver(&info, &ka, regs, 0);

	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
		handle_signal(signr, &info, &ka, oldset, regs);

		/*
		 * If a signal was successfully delivered, the saved sigmask
		 * is in its frame, and we can clear the TIF_RESTORE_SIGMASK
		 * flag.
		 */
		if (test_thread_flag(TIF_RESTORE_SIGMASK))
			clear_thread_flag(TIF_RESTORE_SIGMASK);

		return 1;
	}

no_signal:
	/* Did we come from a system call? */
	if (regs->syscall_nr >= 0) {
		/* Restart the system call - no handlers present */
		switch (regs->regs[REG_RET]) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			/* Decode Syscall # */
			regs->regs[REG_RET] = regs->syscall_nr;
			regs->pc -= 4;
			break;

		case -ERESTART_RESTARTBLOCK:
			regs->regs[REG_RET] = __NR_restart_syscall;
			regs->pc -= 4;
			break;
		}
	}

	/* No signal to deliver -- 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);
	}

	return 0;
}