[linux.git] / arch / blackfin / kernel / signal.c

/*
 * 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>

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

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

struct rt_sigframe {
	int sig;
	struct siginfo *pinfo;
	void *puc;
	char retcode[8];
	struct siginfo info;
	struct ucontext uc;
};

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

static inline int
rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext *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 push_cache(unsigned long vaddr, unsigned int len)
{
	flush_icache_range(vaddr, vaddr + len);
}

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));

	/* Set up to return from userspace.  */
	err |= __put_user(0x28, &(frame->retcode[0]));
	err |= __put_user(0xe1, &(frame->retcode[1]));
	err |= __put_user(0xad, &(frame->retcode[2]));
	err |= __put_user(0x00, &(frame->retcode[3]));
	err |= __put_user(0xa0, &(frame->retcode[4]));
	err |= __put_user(0x00, &(frame->retcode[5]));

	if (err)
		goto give_sigsegv;

	push_cache((unsigned long)&frame->retcode, sizeof(frame->retcode));

	/* Set up registers for signal handler */
	wrusp((unsigned long)frame);
	if (get_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 = (unsigned long)(frame->retcode);

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

	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);
	}
}
Commit	Line	Data
1394f032 BW	1	/*
	2	* File: arch/blackfin/kernel/signal.c
	3	* Based on:
	4	* Author:
	5	*
	6	* Created:
	7	* Description:
	8	*
	9	* Modified:
	10	* Copyright 2004-2006 Analog Devices Inc.
	11	*
	12	* Bugs: Enter bugs at http://blackfin.uclinux.org/
	13	*
	14	* This program is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU General Public License as published by
	16	* the Free Software Foundation; either version 2 of the License, or
	17	* (at your option) any later version.
	18	*
	19	* This program is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU General Public License
	25	* along with this program; if not, see the file COPYING, or write
	26	* to the Free Software Foundation, Inc.,
	27	* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	28	*/
	29
	30	#include <linux/signal.h>
	31	#include <linux/syscalls.h>
	32	#include <linux/ptrace.h>
	33	#include <linux/tty.h>
	34	#include <linux/personality.h>
	35	#include <linux/binfmts.h>
	36	#include <linux/freezer.h>
1f83b8f1	37	#include <linux/uaccess.h>
1394f032	38
1394f032 BW	39	#include <asm/cacheflush.h>
	40	#include <asm/ucontext.h>
	41
	42	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	43
	44	struct fdpic_func_descriptor {
	45	unsigned long text;
	46	unsigned long GOT;
	47	};
	48
	49	struct rt_sigframe {
	50	int sig;
	51	struct siginfo *pinfo;
	52	void *puc;
	53	char retcode[8];
	54	struct siginfo info;
	55	struct ucontext uc;
	56	};
	57
	58	asmlinkage int sys_sigaltstack(const stack_t * uss, stack_t * uoss)
	59	{
	60	return do_sigaltstack(uss, uoss, rdusp());
	61	}
	62
	63	static inline int
	64	rt_restore_sigcontext(struct pt_regs regs, struct sigcontext sc, int *pr0)
	65	{
	66	unsigned long usp = 0;
	67	int err = 0;
	68
	69	#define RESTORE(x) err \|= __get_user(regs->x, &sc->sc_##x)
	70
	71	/* restore passed registers */
	72	RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
	73	RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
	74	RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
	75	RESTORE(p4); RESTORE(p5);
	76	err \|= __get_user(usp, &sc->sc_usp);
	77	wrusp(usp);
	78	RESTORE(a0w); RESTORE(a1w);
	79	RESTORE(a0x); RESTORE(a1x);
	80	RESTORE(astat);
	81	RESTORE(rets);
	82	RESTORE(pc);
	83	RESTORE(retx);
	84	RESTORE(fp);
	85	RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
	86	RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
	87	RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
	88	RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
	89	RESTORE(lc0); RESTORE(lc1);
	90	RESTORE(lt0); RESTORE(lt1);
	91	RESTORE(lb0); RESTORE(lb1);
	92	RESTORE(seqstat);
	93
	94	regs->orig_p0 = -1; /* disable syscall checks */
	95
	96	*pr0 = regs->r0;
	97	return err;
	98	}
	99
	100	asmlinkage int do_rt_sigreturn(unsigned long __unused)
	101	{
	102	struct pt_regs regs = (struct pt_regs )__unused;
103	unsigned long usp = rdusp();
104	struct rt_sigframe frame = (struct rt_sigframe )(usp);
105	sigset_t set;
106	int r0;
107
108	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
109	goto badframe;
110	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
111	goto badframe;
112
113	sigdelsetmask(&set, ~_BLOCKABLE);
114	spin_lock_irq(&current->sighand->siglock);
115	current->blocked = set;
116	recalc_sigpending();
117	spin_unlock_irq(&current->sighand->siglock);
118
119	if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
120	goto badframe;
121
122	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
123	goto badframe;
124
125	return r0;
126
1f83b8f1	127	badframe:
1394f032 BW	128	force_sig(SIGSEGV, current);
	129	return 0;
	130	}
	131
	132	static inline int rt_setup_sigcontext(struct sigcontext sc, struct pt_regs regs)
	133	{
	134	int err = 0;
	135
	136	#define SETUP(x) err \|= __put_user(regs->x, &sc->sc_##x)
	137
	138	SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
	139	SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
	140	SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
	141	SETUP(p4); SETUP(p5);
	142	err \|= __put_user(rdusp(), &sc->sc_usp);
	143	SETUP(a0w); SETUP(a1w);
	144	SETUP(a0x); SETUP(a1x);
	145	SETUP(astat);
	146	SETUP(rets);
	147	SETUP(pc);
	148	SETUP(retx);
	149	SETUP(fp);
	150	SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
	151	SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
	152	SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
	153	SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
	154	SETUP(lc0); SETUP(lc1);
	155	SETUP(lt0); SETUP(lt1);
	156	SETUP(lb0); SETUP(lb1);
	157	SETUP(seqstat);
	158
	159	return err;
	160	}
	161
	162	static inline void push_cache(unsigned long vaddr, unsigned int len)
	163	{
	164	flush_icache_range(vaddr, vaddr + len);
	165	}
	166
	167	static inline void get_sigframe(struct k_sigaction ka, struct pt_regs *regs,
	168	size_t frame_size)
	169	{
	170	unsigned long usp;
	171
	172	/* Default to using normal stack. */
	173	usp = rdusp();
	174
	175	/* This is the X/Open sanctioned signal stack switching. */
	176	if (ka->sa.sa_flags & SA_ONSTACK) {
	177	if (!on_sig_stack(usp))
	178	usp = current->sas_ss_sp + current->sas_ss_size;
	179	}
	180	return (void *)((usp - frame_size) & -8UL);
	181	}
	182
	183	static int
	184	setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	185	sigset_t * set, struct pt_regs *regs)
	186	{
	187	struct rt_sigframe *frame;
	188	int err = 0;
	189
	190	frame = get_sigframe(ka, regs, sizeof(*frame));
	191
192	err \|= __put_user((current_thread_info()->exec_domain
193	&& current_thread_info()->exec_domain->signal_invmap
194	&& sig < 32
195	? current_thread_info()->exec_domain->
196	signal_invmap[sig] : sig), &frame->sig);
197
198	err \|= __put_user(&frame->info, &frame->pinfo);
199	err \|= __put_user(&frame->uc, &frame->puc);
200	err \|= copy_siginfo_to_user(&frame->info, info);
201
202	/* Create the ucontext. */
203	err \|= __put_user(0, &frame->uc.uc_flags);
204	err \|= __put_user(0, &frame->uc.uc_link);
205	err \|=
206	__put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
207	err \|= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
208	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
209	err \|= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
210	err \|= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
211
212	/* Set up to return from userspace. */
213	err \|= __put_user(0x28, &(frame->retcode[0]));
214	err \|= __put_user(0xe1, &(frame->retcode[1]));
215	err \|= __put_user(0xad, &(frame->retcode[2]));
216	err \|= __put_user(0x00, &(frame->retcode[3]));
217	err \|= __put_user(0xa0, &(frame->retcode[4]));
218	err \|= __put_user(0x00, &(frame->retcode[5]));
219
220	if (err)
221	goto give_sigsegv;
222
223	push_cache((unsigned long)&frame->retcode, sizeof(frame->retcode));
224
225	/* Set up registers for signal handler */
226	wrusp((unsigned long)frame);
227	if (get_personality & FDPIC_FUNCPTRS) {
228	struct fdpic_func_descriptor __user *funcptr =
229	(struct fdpic_func_descriptor *) ka->sa.sa_handler;
230	__get_user(regs->pc, &funcptr->text);
231	__get_user(regs->p3, &funcptr->GOT);
232	} else
233	regs->pc = (unsigned long)ka->sa.sa_handler;
234	regs->rets = (unsigned long)(frame->retcode);
235
236	regs->r0 = frame->sig;
237	regs->r1 = (unsigned long)(&frame->info);
238	regs->r2 = (unsigned long)(&frame->uc);
239
240	return 0;
241
1f83b8f1	242	give_sigsegv:
1394f032 BW	243	if (sig == SIGSEGV)
	244	ka->sa.sa_handler = SIG_DFL;
	245	force_sig(SIGSEGV, current);
	246	return -EFAULT;
	247	}
	248
	249	static inline void
	250	handle_restart(struct pt_regs regs, struct k_sigaction ka, int has_handler)
	251	{
	252	switch (regs->r0) {
	253	case -ERESTARTNOHAND:
	254	if (!has_handler)
	255	goto do_restart;
	256	regs->r0 = -EINTR;
	257	break;
	258
	259	case -ERESTARTSYS:
	260	if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
	261	regs->r0 = -EINTR;
	262	break;
	263	}
	264	/* fallthrough */
	265	case -ERESTARTNOINTR:
1f83b8f1	266	do_restart:
1394f032 BW	267	regs->p0 = regs->orig_p0;
	268	regs->r0 = regs->orig_r0;
	269	regs->pc -= 2;
	270	break;
	271	}
	272	}
	273
	274	/*
	275	* OK, we're invoking a handler
	276	*/
	277	static int
	278	handle_signal(int sig, siginfo_t info, struct k_sigaction ka,
	279	sigset_t oldset, struct pt_regs regs)
	280	{
	281	int ret;
	282
	283	/* are we from a system call? to see pt_regs->orig_p0 */
	284	if (regs->orig_p0 >= 0)
	285	/* If so, check system call restarting.. */
	286	handle_restart(regs, ka, 1);
	287
	288	/* set up the stack frame */
	289	ret = setup_rt_frame(sig, ka, info, oldset, regs);
	290
	291	if (ret == 0) {
	292	spin_lock_irq(&current->sighand->siglock);
	293	sigorsets(&current->blocked, &current->blocked,
	294	&ka->sa.sa_mask);
	295	if (!(ka->sa.sa_flags & SA_NODEFER))
	296	sigaddset(&current->blocked, sig);
	297	recalc_sigpending();
	298	spin_unlock_irq(&current->sighand->siglock);
	299	}
	300	return ret;
	301	}
	302
	303	/*
	304	* Note that 'init' is a special process: it doesn't get signals it doesn't
	305	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	306	* mistake.
	307	*
	308	* Note that we go through the signals twice: once to check the signals
	309	* that the kernel can handle, and then we build all the user-level signal
	310	* handling stack-frames in one go after that.
	311	*/
	312	asmlinkage void do_signal(struct pt_regs *regs)
	313	{
	314	siginfo_t info;
	315	int signr;
	316	struct k_sigaction ka;
	317	sigset_t *oldset;
	318
	319	current->thread.esp0 = (unsigned long)regs;
	320
	321	if (try_to_freeze())
	322	goto no_signal;
	323
	324	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	325	oldset = &current->saved_sigmask;
	326	else
	327	oldset = &current->blocked;
	328
	329	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	330	if (signr > 0) {
331	/* Whee! Actually deliver the signal. */
332	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
333	/* a signal was successfully delivered; the saved
334	* sigmask will have been stored in the signal frame,
335	* and will be restored by sigreturn, so we can simply
336	* clear the TIF_RESTORE_SIGMASK flag */
337	if (test_thread_flag(TIF_RESTORE_SIGMASK))
338	clear_thread_flag(TIF_RESTORE_SIGMASK);
339	}
340
341	return;
342	}
343
1f83b8f1	344	no_signal:
1394f032 BW	345	/* Did we come from a system call? */
	346	if (regs->orig_p0 >= 0)
	347	/* Restart the system call - no handlers present */
	348	handle_restart(regs, NULL, 0);
	349
	350	/* if there's no signal to deliver, we just put the saved sigmask
	351	* back */
	352	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	353	clear_thread_flag(TIF_RESTORE_SIGMASK);
	354	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	355	}
	356	}