[deliverable/linux.git] / arch / cris / arch-v10 / kernel / signal.c

/*
 *  linux/arch/cris/kernel/signal.c
 *
 *  Based on arch/i386/kernel/signal.c by
 *     Copyright (C) 1991, 1992  Linus Torvalds
 *     1997-11-28  Modified for POSIX.1b signals by Richard Henderson *
 *
 *  Ideas also taken from arch/arm.
 *
 *  Copyright (C) 2000-2007 Axis Communications AB
 *
 *  Authors:  Bjorn Wesen (bjornw@axis.com)
 *
 */

#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/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>

#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <arch/system.h>

#define DEBUG_SIG 0

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

/* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */
/* manipulate regs so that upon return, it will be re-executed */

/* We rely on that pc points to the instruction after "break 13", so the
 * library must never do strange things like putting it in a delay slot.
 */
#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2;

void do_signal(int canrestart, struct pt_regs *regs);

/*
 * Atomically swap in the new signal mask, and wait for a signal.  Define
 * dummy arguments to be able to reach the regs argument.  (Note that this
 * arrangement relies on old_sigset_t occupying one register.)
 */
int sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof,
	long srp, struct pt_regs *regs)
{
	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	current->saved_sigmask = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	current->state = TASK_INTERRUPTIBLE;
	schedule();
	set_thread_flag(TIF_RESTORE_SIGMASK);
	return -ERESTARTNOHAND;
}

int sys_sigaction(int sig, const struct old_sigaction __user *act,
	struct old_sigaction *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;
}

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


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

struct sigframe {
	struct sigcontext sc;
	unsigned long extramask[_NSIG_WORDS-1];
	unsigned char retcode[8];  /* trampoline code */
};

struct rt_sigframe {
	struct siginfo *pinfo;
	void *puc;
	struct siginfo info;
	struct ucontext uc;
	unsigned char retcode[8];  /* trampoline code */
};


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

        /* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	/* restore the regs from &sc->regs (same as sc, since regs is first)
	 * (sc is already checked for VERIFY_READ since the sigframe was
	 *  checked in sys_sigreturn previously)
	 */

	if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
                goto badframe;

	/* make sure the U-flag is set so user-mode cannot fool us */

	regs->dccr |= 1 << 8;

	/* restore the old USP as it was before we stacked the sc etc.
	 * (we cannot just pop the sigcontext since we aligned the sp and
	 *  stuff after pushing it)
	 */

	err |= __get_user(old_usp, &sc->usp);

	wrusp(old_usp);

	/* TODO: the other ports use regs->orig_XX to disable syscall checks
	 * after this completes, but we don't use that mechanism. maybe we can
	 * use it now ?
	 */

	return err;

badframe:
	return 1;
}

/* Define dummy arguments to be able to reach the regs argument.  */

asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof,
                             long srp, struct pt_regs *regs)
{
	struct sigframe __user *frame = (struct sigframe *)rdusp();
	sigset_t set;

        /*
         * Since we stacked the signal on a dword boundary,
         * then frame should be dword aligned here.  If it's
         * not, then the user is trying to mess with us.
         */
        if (((long)frame) & 3)
                goto badframe;

	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))
		goto badframe;

	/* TODO: SIGTRAP when single-stepping as in arm ? */

	return regs->r10;

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

/* Define dummy arguments to be able to reach the regs argument.  */

asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13,
                                long mof, long srp, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame = (struct rt_sigframe *)rdusp();
	sigset_t set;

        /*
         * Since we stacked the signal on a dword boundary,
         * then frame should be dword aligned here.  If it's
         * not, then the user is trying to mess with us.
         */
        if (((long)frame) & 3)
                goto badframe;

	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))
		goto badframe;

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

	return regs->r10;

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;
	unsigned long usp = rdusp();

	/* copy the regs. they are first in sc so we can use sc directly */

	err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));

        /* Set the frametype to CRIS_FRAME_NORMAL for the execution of
           the signal handler. The frametype will be restored to its previous
           value in restore_sigcontext. */
        regs->frametype = CRIS_FRAME_NORMAL;

	/* then some other stuff */

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

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

	return err;
}

/* Figure out where we want to put the new signal frame
 * - usually on the stack. */

static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
{
	unsigned long sp = rdusp();

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

	/* make sure the frame is dword-aligned */

	sp &= ~3;

	return (void __user*)(sp - frame_size);
}

/* grab and setup a signal frame.
 *
 * basically we stack a lot of state info, and arrange for the
 * user-mode program to return to the kernel using either a
 * trampoline which performs the syscall sigreturn, or a provided
 * user-mode trampoline.
 */

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

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

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

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

	if (_NSIG_WORDS > 1) {
		err |= __copy_to_user(frame->extramask, &set->sig[1],
				      sizeof(frame->extramask));
	}
	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) {
		return_ip = (unsigned long)ka->sa.sa_restorer;
	} else {
		/* trampoline - the desired return ip is the retcode itself */
		return_ip = (unsigned long)&frame->retcode;
		/* This is movu.w __NR_sigreturn, r9; break 13; */
		err |= __put_user(0x9c5f,         (short __user*)(frame->retcode+0));
		err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2));
		err |= __put_user(0xe93d,         (short __user*)(frame->retcode+4));
	}

	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */

	regs->irp = (unsigned long) ka->sa.sa_handler;  /* what we enter NOW   */
	regs->srp = return_ip;                          /* what we enter LATER */
	regs->r10 = sig;                                /* first argument is signo */

	/* actually move the usp to reflect the stacked frame */

	wrusp((unsigned long)frame);

	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

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

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

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

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

	/* Clear all the bits of the ucontext we don't use.  */
        err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));

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

	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	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) {
		return_ip = (unsigned long)ka->sa.sa_restorer;
	} else {
		/* trampoline - the desired return ip is the retcode itself */
		return_ip = (unsigned long)&frame->retcode;
		/* This is movu.w __NR_rt_sigreturn, r9; break 13; */
		err |= __put_user(0x9c5f, (short __user *)(frame->retcode+0));
		err |= __put_user(__NR_rt_sigreturn,
			(short __user *)(frame->retcode+2));
		err |= __put_user(0xe93d, (short __user *)(frame->retcode+4));
	}

	if (err)
		goto give_sigsegv;

	/* TODO what is the current->exec_domain stuff and invmap ? */

	/* Set up registers for signal handler */

	/* What we enter NOW   */
	regs->irp = (unsigned long) ka->sa.sa_handler;
	/* What we enter LATER */
	regs->srp = return_ip;
	/* First argument is signo */
	regs->r10 = sig;
	/* Second argument is (siginfo_t *) */
	regs->r11 = (unsigned long)&frame->info;
	/* Third argument is unused */
	regs->r12 = 0;

	/* Actually move the usp to reflect the stacked frame */
	wrusp((unsigned long)frame);

	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

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

static inline int handle_signal(int canrestart, unsigned long sig,
	siginfo_t *info, struct k_sigaction *ka,
	sigset_t *oldset, struct pt_regs *regs)
{
	int ret;

	/* Are we from a system call? */
	if (canrestart) {
		/* If so, check system call restarting.. */
		switch (regs->r10) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			/* ERESTARTNOHAND means that the syscall should
			 * only be restarted if there was no handler for
			 * the signal, and since we only get here if there
			 * is a handler, we don't restart */
			regs->r10 = -EINTR;
			break;
		case -ERESTARTSYS:
			/* ERESTARTSYS means to restart the syscall if
			 * there is no handler or the handler was
			 * registered with SA_RESTART */
			if (!(ka->sa.sa_flags & SA_RESTART)) {
				regs->r10 = -EINTR;
				break;
			}
		/* fallthrough */
		case -ERESTARTNOINTR:
			/* ERESTARTNOINTR means that the syscall should
			 * be called again after the signal handler returns. */
			RESTART_CRIS_SYS(regs);
		}
	}

	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		ret = setup_rt_frame(sig, ka, info, oldset, regs);
	else
		ret = setup_frame(sig, ka, 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.
 *
 * Also note that the regs structure given here as an argument, is the latest
 * pushed pt_regs. It may or may not be the same as the first pushed registers
 * when the initial usermode->kernelmode transition took place. Therefore
 * we can use user_mode(regs) to see if we came directly from kernel or user
 * mode below.
 */

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

	/*
	 * 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;

	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(canrestart, signr, &info, &ka,
				oldset, regs)) {
			/* 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;
	}

	/* Did we come from a system call? */
	if (canrestart) {
		/* Restart the system call - no handlers present */
		if (regs->r10 == -ERESTARTNOHAND ||
		    regs->r10 == -ERESTARTSYS ||
		    regs->r10 == -ERESTARTNOINTR) {
			RESTART_CRIS_SYS(regs);
		}
		if (regs->r10 == -ERESTART_RESTARTBLOCK) {
			regs->r9 = __NR_restart_syscall;
			regs->irp -= 2;
		}
	}

	/* 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);
	}
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/cris/kernel/signal.c
	3	*
	4	* Based on arch/i386/kernel/signal.c by
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson *
	7	*
	8	* Ideas also taken from arch/arm.
	9	*
a4858d4d	10	* Copyright (C) 2000-2007 Axis Communications AB
1da177e4 LT	11	*
	12	* Authors: Bjorn Wesen (bjornw@axis.com)
	13	*
	14	*/
	15
	16	#include <linux/sched.h>
	17	#include <linux/mm.h>
	18	#include <linux/smp.h>
1da177e4 LT	19	#include <linux/kernel.h>
	20	#include <linux/signal.h>
	21	#include <linux/errno.h>
	22	#include <linux/wait.h>
	23	#include <linux/ptrace.h>
	24	#include <linux/unistd.h>
	25	#include <linux/stddef.h>
	26
	27	#include <asm/processor.h>
	28	#include <asm/ucontext.h>
	29	#include <asm/uaccess.h>
b1a154db	30	#include <arch/system.h>
1da177e4 LT	31
	32	#define DEBUG_SIG 0
	33
	34	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	35
	36	/* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */
	37	/* manipulate regs so that upon return, it will be re-executed */
	38
	39	/* We rely on that pc points to the instruction after "break 13", so the
	40	* library must never do strange things like putting it in a delay slot.
	41	*/
	42	#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2;
	43
a4858d4d	44	void do_signal(int canrestart, struct pt_regs *regs);
1da177e4 LT	45
1da177e4 LT	46	/*
a4858d4d	47	* Atomically swap in the new signal mask, and wait for a signal. Define
1da177e4 LT	48	* dummy arguments to be able to reach the regs argument. (Note that this
	49	* arrangement relies on old_sigset_t occupying one register.)
	50	*/
a4858d4d JN	51	int sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof,
a4858d4d JN	52	long srp, struct pt_regs *regs)
1da177e4	53	{
1da177e4 LT	54	mask &= _BLOCKABLE;
1da177e4 LT	55	spin_lock_irq(&current->sighand->siglock);
a4858d4d	56	current->saved_sigmask = current->blocked;
1da177e4 LT	57	siginitset(&current->blocked, mask);
	58	recalc_sigpending();
	59	spin_unlock_irq(&current->sighand->siglock);
a4858d4d JN	60	current->state = TASK_INTERRUPTIBLE;
	61	schedule();
	62	set_thread_flag(TIF_RESTORE_SIGMASK);
	63	return -ERESTARTNOHAND;
1da177e4 LT	64	}
1da177e4 LT	65
a4858d4d JN	66	int sys_sigaction(int sig, const struct old_sigaction __user *act,
a4858d4d JN	67	struct old_sigaction *oact)
1da177e4 LT	68	{
	69	struct k_sigaction new_ka, old_ka;
	70	int ret;
	71
	72	if (act) {
	73	old_sigset_t mask;
	74	if (!access_ok(VERIFY_READ, act, sizeof(*act)) \|\|
	75	__get_user(new_ka.sa.sa_handler, &act->sa_handler) \|\|
	76	__get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
	77	return -EFAULT;
	78	__get_user(new_ka.sa.sa_flags, &act->sa_flags);
	79	__get_user(mask, &act->sa_mask);
	80	siginitset(&new_ka.sa.sa_mask, mask);
	81	}
	82
	83	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
	84
	85	if (!ret && oact) {
	86	if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) \|\|
	87	__put_user(old_ka.sa.sa_handler, &oact->sa_handler) \|\|
	88	__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
	89	return -EFAULT;
	90	__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
	91	__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	92	}
	93
	94	return ret;
	95	}
	96
a4858d4d	97	int sys_sigaltstack(const stack_t uss, stack_t __user uoss)
1da177e4 LT	98	{
	99	return do_sigaltstack(uss, uoss, rdusp());
	100	}
	101
	102
	103	/*
	104	* Do a signal return; undo the signal stack.
	105	*/
	106
	107	struct sigframe {
	108	struct sigcontext sc;
	109	unsigned long extramask[_NSIG_WORDS-1];
	110	unsigned char retcode[8]; /* trampoline code */
	111	};
	112
	113	struct rt_sigframe {
	114	struct siginfo *pinfo;
	115	void *puc;
	116	struct siginfo info;
	117	struct ucontext uc;
	118	unsigned char retcode[8]; /* trampoline code */
	119	};
	120
	121
	122	static int
	123	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc)
	124	{
	125	unsigned int err = 0;
	126	unsigned long old_usp;
	127
	128	/* Always make any pending restarted system calls return -EINTR */
	129	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	130
	131	/* restore the regs from &sc->regs (same as sc, since regs is first)
	132	* (sc is already checked for VERIFY_READ since the sigframe was
	133	* checked in sys_sigreturn previously)
	134	*/
	135
	136	if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
	137	goto badframe;
	138
	139	/* make sure the U-flag is set so user-mode cannot fool us */
	140
	141	regs->dccr \|= 1 << 8;
	142
	143	/* restore the old USP as it was before we stacked the sc etc.
	144	* (we cannot just pop the sigcontext since we aligned the sp and
	145	* stuff after pushing it)
	146	*/
	147
	148	err \|= __get_user(old_usp, &sc->usp);
	149
	150	wrusp(old_usp);
	151
	152	/* TODO: the other ports use regs->orig_XX to disable syscall checks
	153	* after this completes, but we don't use that mechanism. maybe we can
a4858d4d	154	* use it now ?
1da177e4 LT	155	*/
	156
	157	return err;
	158
	159	badframe:
	160	return 1;
	161	}
	162
	163	/* Define dummy arguments to be able to reach the regs argument. */
	164
a4858d4d	165	asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof,
1da177e4 LT	166	long srp, struct pt_regs *regs)
	167	{
	168	struct sigframe __user frame = (struct sigframe )rdusp();
	169	sigset_t set;
	170
	171	/*
	172	* Since we stacked the signal on a dword boundary,
	173	* then frame should be dword aligned here. If it's
	174	* not, then the user is trying to mess with us.
	175	*/
	176	if (((long)frame) & 3)
	177	goto badframe;
	178
	179	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	180	goto badframe;
	181	if (__get_user(set.sig[0], &frame->sc.oldmask)
	182	\|\| (_NSIG_WORDS > 1
	183	&& __copy_from_user(&set.sig[1], frame->extramask,
	184	sizeof(frame->extramask))))
	185	goto badframe;
	186
	187	sigdelsetmask(&set, ~_BLOCKABLE);
	188	spin_lock_irq(&current->sighand->siglock);
	189	current->blocked = set;
	190	recalc_sigpending();
	191	spin_unlock_irq(&current->sighand->siglock);
a4858d4d	192
1da177e4 LT	193	if (restore_sigcontext(regs, &frame->sc))
	194	goto badframe;
	195
	196	/* TODO: SIGTRAP when single-stepping as in arm ? */
	197
	198	return regs->r10;
	199
	200	badframe:
	201	force_sig(SIGSEGV, current);
	202	return 0;
a4858d4d	203	}
1da177e4 LT	204
	205	/* Define dummy arguments to be able to reach the regs argument. */
	206
a4858d4d	207	asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13,
1da177e4 LT	208	long mof, long srp, struct pt_regs *regs)
	209	{
	210	struct rt_sigframe __user frame = (struct rt_sigframe )rdusp();
	211	sigset_t set;
	212
	213	/*
	214	* Since we stacked the signal on a dword boundary,
	215	* then frame should be dword aligned here. If it's
	216	* not, then the user is trying to mess with us.
	217	*/
	218	if (((long)frame) & 3)
	219	goto badframe;
	220
	221	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	222	goto badframe;
	223	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	224	goto badframe;
	225
	226	sigdelsetmask(&set, ~_BLOCKABLE);
	227	spin_lock_irq(&current->sighand->siglock);
	228	current->blocked = set;
	229	recalc_sigpending();
	230	spin_unlock_irq(&current->sighand->siglock);
a4858d4d	231
1da177e4 LT	232	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	233	goto badframe;
	234
	235	if (do_sigaltstack(&frame->uc.uc_stack, NULL, rdusp()) == -EFAULT)
	236	goto badframe;
	237
	238	return regs->r10;
	239
	240	badframe:
	241	force_sig(SIGSEGV, current);
	242	return 0;
a4858d4d	243	}
1da177e4 LT	244
	245	/*
	246	* Set up a signal frame.
	247	*/
	248
a4858d4d JN	249	static int setup_sigcontext(struct sigcontext __user *sc,
a4858d4d JN	250	struct pt_regs *regs, unsigned long mask)
1da177e4 LT	251	{
	252	int err = 0;
	253	unsigned long usp = rdusp();
	254
	255	/* copy the regs. they are first in sc so we can use sc directly */
	256
	257	err \|= __copy_to_user(sc, regs, sizeof(struct pt_regs));
	258
	259	/* Set the frametype to CRIS_FRAME_NORMAL for the execution of
	260	the signal handler. The frametype will be restored to its previous
	261	value in restore_sigcontext. */
	262	regs->frametype = CRIS_FRAME_NORMAL;
	263
	264	/* then some other stuff */
	265
	266	err \|= __put_user(mask, &sc->oldmask);
	267
	268	err \|= __put_user(usp, &sc->usp);
	269
	270	return err;
	271	}
	272
a4858d4d JN	273	/* Figure out where we want to put the new signal frame
a4858d4d JN	274	* - usually on the stack. */
1da177e4 LT	275
1da177e4 LT	276	static inline void __user *
a4858d4d	277	get_sigframe(struct k_sigaction ka, struct pt_regs regs, size_t frame_size)
1da177e4 LT	278	{
	279	unsigned long sp = rdusp();
	280
	281	/* This is the X/Open sanctioned signal stack switching. */
	282	if (ka->sa.sa_flags & SA_ONSTACK) {
	283	if (! on_sig_stack(sp))
	284	sp = current->sas_ss_sp + current->sas_ss_size;
	285	}
	286
	287	/* make sure the frame is dword-aligned */
	288
	289	sp &= ~3;
	290
	291	return (void __user*)(sp - frame_size);
	292	}
	293
	294	/* grab and setup a signal frame.
a4858d4d	295	*
1da177e4 LT	296	* basically we stack a lot of state info, and arrange for the
	297	* user-mode program to return to the kernel using either a
	298	* trampoline which performs the syscall sigreturn, or a provided
	299	* user-mode trampoline.
	300	*/
	301
a4858d4d JN	302	static int setup_frame(int sig, struct k_sigaction *ka,
a4858d4d JN	303	sigset_t set, struct pt_regs regs)
1da177e4 LT	304	{
	305	struct sigframe __user *frame;
	306	unsigned long return_ip;
	307	int err = 0;
	308
	309	frame = get_sigframe(ka, regs, sizeof(*frame));
	310
	311	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	312	goto give_sigsegv;
	313
	314	err \|= setup_sigcontext(&frame->sc, regs, set->sig[0]);
	315	if (err)
	316	goto give_sigsegv;
	317
	318	if (_NSIG_WORDS > 1) {
	319	err \|= __copy_to_user(frame->extramask, &set->sig[1],
	320	sizeof(frame->extramask));
	321	}
	322	if (err)
	323	goto give_sigsegv;
	324
	325	/* Set up to return from userspace. If provided, use a stub
	326	already in userspace. */
	327	if (ka->sa.sa_flags & SA_RESTORER) {
	328	return_ip = (unsigned long)ka->sa.sa_restorer;
	329	} else {
	330	/* trampoline - the desired return ip is the retcode itself */
	331	return_ip = (unsigned long)&frame->retcode;
	332	/* This is movu.w __NR_sigreturn, r9; break 13; */
	333	err \|= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
	334	err \|= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2));
	335	err \|= __put_user(0xe93d, (short __user*)(frame->retcode+4));
	336	}
	337
	338	if (err)
	339	goto give_sigsegv;
	340
	341	/* Set up registers for signal handler */
	342
	343	regs->irp = (unsigned long) ka->sa.sa_handler; /* what we enter NOW */
	344	regs->srp = return_ip; /* what we enter LATER */
	345	regs->r10 = sig; /* first argument is signo */
	346
	347	/* actually move the usp to reflect the stacked frame */
	348
	349	wrusp((unsigned long)frame);
	350
a4858d4d	351	return 0;
1da177e4 LT	352
	353	give_sigsegv:
	354	force_sigsegv(sig, current);
a4858d4d	355	return -EFAULT;
1da177e4 LT	356	}
1da177e4 LT	357
a4858d4d JN	358	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
a4858d4d JN	359	sigset_t set, struct pt_regs regs)
1da177e4 LT	360	{
	361	struct rt_sigframe __user *frame;
	362	unsigned long return_ip;
	363	int err = 0;
	364
	365	frame = get_sigframe(ka, regs, sizeof(*frame));
	366
	367	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	368	goto give_sigsegv;
	369
	370	err \|= __put_user(&frame->info, &frame->pinfo);
	371	err \|= __put_user(&frame->uc, &frame->puc);
	372	err \|= copy_siginfo_to_user(&frame->info, info);
	373	if (err)
	374	goto give_sigsegv;
	375
	376	/* Clear all the bits of the ucontext we don't use. */
	377	err \|= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
	378
	379	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
	380
	381	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	382
	383	if (err)
	384	goto give_sigsegv;
	385
	386	/* Set up to return from userspace. If provided, use a stub
	387	already in userspace. */
	388	if (ka->sa.sa_flags & SA_RESTORER) {
	389	return_ip = (unsigned long)ka->sa.sa_restorer;
	390	} else {
	391	/* trampoline - the desired return ip is the retcode itself */
	392	return_ip = (unsigned long)&frame->retcode;
	393	/* This is movu.w __NR_rt_sigreturn, r9; break 13; */
a4858d4d JN	394	err \|= __put_user(0x9c5f, (short __user *)(frame->retcode+0));
	395	err \|= __put_user(__NR_rt_sigreturn,
	396	(short __user *)(frame->retcode+2));
	397	err \|= __put_user(0xe93d, (short __user *)(frame->retcode+4));
1da177e4 LT	398	}
	399
	400	if (err)
	401	goto give_sigsegv;
	402
	403	/* TODO what is the current->exec_domain stuff and invmap ? */
	404
	405	/* Set up registers for signal handler */
	406
a4858d4d JN	407	/* What we enter NOW */
	408	regs->irp = (unsigned long) ka->sa.sa_handler;
	409	/* What we enter LATER */
	410	regs->srp = return_ip;
	411	/* First argument is signo */
	412	regs->r10 = sig;
	413	/* Second argument is (siginfo_t ) /
	414	regs->r11 = (unsigned long)&frame->info;
	415	/* Third argument is unused */
	416	regs->r12 = 0;
	417
	418	/* Actually move the usp to reflect the stacked frame */
1da177e4 LT	419	wrusp((unsigned long)frame);
1da177e4 LT	420
a4858d4d	421	return 0;
1da177e4 LT	422
	423	give_sigsegv:
	424	force_sigsegv(sig, current);
a4858d4d	425	return -EFAULT;
1da177e4 LT	426	}
	427
	428	/*
	429	* OK, we're invoking a handler
a4858d4d	430	*/
1da177e4	431
a4858d4d JN	432	static inline int handle_signal(int canrestart, unsigned long sig,
	433	siginfo_t info, struct k_sigaction ka,
	434	sigset_t oldset, struct pt_regs regs)
1da177e4	435	{
a4858d4d JN	436	int ret;
a4858d4d JN	437
1da177e4 LT	438	/* Are we from a system call? */
	439	if (canrestart) {
	440	/* If so, check system call restarting.. */
	441	switch (regs->r10) {
a4858d4d JN	442	case -ERESTART_RESTARTBLOCK:
	443	case -ERESTARTNOHAND:
	444	/* ERESTARTNOHAND means that the syscall should
	445	* only be restarted if there was no handler for
	446	* the signal, and since we only get here if there
	447	* is a handler, we don't restart */
	448	regs->r10 = -EINTR;
	449	break;
	450	case -ERESTARTSYS:
	451	/* ERESTARTSYS means to restart the syscall if
	452	* there is no handler or the handler was
	453	* registered with SA_RESTART */
	454	if (!(ka->sa.sa_flags & SA_RESTART)) {
1da177e4 LT	455	regs->r10 = -EINTR;
1da177e4 LT	456	break;
a4858d4d JN	457	}
	458	/* fallthrough */
	459	case -ERESTARTNOINTR:
	460	/* ERESTARTNOINTR means that the syscall should
	461	* be called again after the signal handler returns. */
	462	RESTART_CRIS_SYS(regs);
1da177e4 LT	463	}
	464	}
	465
	466	/* Set up the stack frame */
	467	if (ka->sa.sa_flags & SA_SIGINFO)
a4858d4d	468	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	469	else
a4858d4d JN	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	return ret;
1da177e4 LT	482	}
	483
	484	/*
	485	* Note that 'init' is a special process: it doesn't get signals it doesn't
	486	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	487	* mistake.
	488	*
	489	* Also note that the regs structure given here as an argument, is the latest
	490	* pushed pt_regs. It may or may not be the same as the first pushed registers
	491	* when the initial usermode->kernelmode transition took place. Therefore
	492	* we can use user_mode(regs) to see if we came directly from kernel or user
	493	* mode below.
	494	*/
	495
a4858d4d	496	void do_signal(int canrestart, struct pt_regs *regs)
1da177e4 LT	497	{
	498	siginfo_t info;
	499	int signr;
	500	struct k_sigaction ka;
a4858d4d	501	sigset_t *oldset;
1da177e4 LT	502
	503	/*
	504	* We want the common case to go fast, which
	505	* is why we may in certain cases get here from
	506	* kernel mode. Just return without doing anything
	507	* if so.
	508	*/
	509	if (!user_mode(regs))
a4858d4d	510	return;
1da177e4	511
a4858d4d JN	512	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	513	oldset = &current->saved_sigmask;
	514	else
1da177e4 LT	515	oldset = &current->blocked;
	516
	517	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	518	if (signr > 0) {
	519	/* Whee! Actually deliver the signal. */
a4858d4d JN	520	if (handle_signal(canrestart, signr, &info, &ka,
	521	oldset, regs)) {
	522	/* a signal was successfully delivered; the saved
	523	* sigmask will have been stored in the signal frame,
	524	* and will be restored by sigreturn, so we can simply
	525	* clear the TIF_RESTORE_SIGMASK flag */
	526	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	527	clear_thread_flag(TIF_RESTORE_SIGMASK);
	528	}
	529	return;
1da177e4 LT	530	}
	531
	532	/* Did we come from a system call? */
	533	if (canrestart) {
	534	/* Restart the system call - no handlers present */
	535	if (regs->r10 == -ERESTARTNOHAND \|\|
	536	regs->r10 == -ERESTARTSYS \|\|
	537	regs->r10 == -ERESTARTNOINTR) {
	538	RESTART_CRIS_SYS(regs);
	539	}
a4858d4d	540	if (regs->r10 == -ERESTART_RESTARTBLOCK) {
33dc0ad7	541	regs->r9 = __NR_restart_syscall;
1da177e4 LT	542	regs->irp -= 2;
	543	}
	544	}
a4858d4d JN	545
	546	/* if there's no signal to deliver, we just put the saved sigmask
	547	* back */
	548	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	549	clear_thread_flag(TIF_RESTORE_SIGMASK);
	550	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	551	}
1da177e4	552	}