arch/microblaze/kernel/signal.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Signal handling
  *
  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
  * Copyright (C) 2008-2009 PetaLogix
  * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
  * Copyright (C) 2001 NEC Corporation
  * Copyright (C) 2001 Miles Bader <miles@gnu.org>
  * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
  * Copyright (C) 1991,1992 Linus Torvalds
  *
  * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
  *
  * This file was was derived from the sh version, arch/sh/kernel/signal.c
  *
  * 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.
  */

 #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 <linux/personality.h>
 #include <linux/percpu.h>
 #include <linux/linkage.h>
 #include <asm/entry.h>
 #include <asm/ucontext.h>
 #include <linux/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <linux/syscalls.h>
 #include <asm/cacheflush.h>
 #include <asm/syscalls.h>

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

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

 asmlinkage long
 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 		struct pt_regs *regs)
 {
 	return do_sigaltstack(uss, uoss, regs->r1);
 }

 /*
  * Do a signal return; undo the signal stack.
  */
 struct sigframe {
 	struct sigcontext sc;
 	unsigned long extramask[_NSIG_WORDS-1];
 	unsigned long tramp[2];	/* signal trampoline */
 };

 struct rt_sigframe {
 	struct siginfo info;
 	struct ucontext uc;
 	unsigned long tramp[2];	/* signal trampoline */
 };

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

 #define COPY(x)		{err |= __get_user(regs->x, &sc->regs.x); }
 	COPY(r0);
 	COPY(r1);
 	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
 	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
 	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
 	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
 	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
 	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
 	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
 	COPY(r30);	COPY(r31);
 	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
 #undef COPY

 	*rval_p = regs->r3;

 	return err;
 }

 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 {
 	struct rt_sigframe __user *frame =
 		(struct rt_sigframe __user *)(regs->r1);

 	sigset_t set;
 	int rval;

 	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, &rval))
 		goto badframe;

 	/* It is more difficult to avoid calling this function than to
 	 call it and ignore errors. */
 	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->r1))
 		goto badframe;

 	return rval;

 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;

 #define COPY(x)		{err |= __put_user(regs->x, &sc->regs.x); }
 	COPY(r0);
 	COPY(r1);
 	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
 	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
 	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
 	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
 	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
 	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
 	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
 	COPY(r30);	COPY(r31);
 	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
 #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, struct pt_regs *regs, size_t frame_size)
 {
 	/* Default to using normal stack */
 	unsigned long sp = regs->r1;

 	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp))
 		sp = current->sas_ss_sp + current->sas_ss_size;

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

 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;
 	unsigned long address = 0;
 #ifdef CONFIG_MMU
 	pmd_t *pmdp;
 	pte_t *ptep;
 #endif

 	frame = get_sigframe(ka, regs, 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;

 	if (info)
 		err |= copy_siginfo_to_user(&frame->info, info);

 	/* Create the ucontext. */
 	err |= __put_user(0, &frame->uc.uc_flags);
 	err |= __put_user(NULL, &frame->uc.uc_link);
 	err |= __put_user((void __user *)current->sas_ss_sp,
 			&frame->uc.uc_stack.ss_sp);
 	err |= __put_user(sas_ss_flags(regs->r1),
 			&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));

 	/* Set up to return from userspace. If provided, use a stub
 	 already in userspace. */
 	/* minus 8 is offset to cater for "rtsd r15,8" */
 	/* addi r12, r0, __NR_sigreturn */
 	err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
 			frame->tramp + 0);
 	/* brki r14, 0x8 */
 	err |= __put_user(0xb9cc0008, frame->tramp + 1);

 	/* Return from sighandler will jump to the tramp.
 	 Negative 8 offset because return is rtsd r15, 8 */
 	regs->r15 = ((unsigned long)frame->tramp)-8;

 	address = ((unsigned long)frame->tramp);
 #ifdef CONFIG_MMU
 	pmdp = pmd_offset(pud_offset(
 			pgd_offset(current->mm, address),
 					address), address);

 	preempt_disable();
 	ptep = pte_offset_map(pmdp, address);
 	if (pte_present(*ptep)) {
 		address = (unsigned long) page_address(pte_page(*ptep));
 		/* MS: I need add offset in page */
 		address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
 		/* MS address is virtual */
 		address = virt_to_phys(address);
 		invalidate_icache_range(address, address + 8);
 		flush_dcache_range(address, address + 8);
 	}
 	pte_unmap(ptep);
 	preempt_enable();
 #else
 	flush_icache_range(address, address + 8);
 	flush_dcache_range(address, address + 8);
 #endif
 	if (err)
 		goto give_sigsegv;

 	/* Set up registers for signal handler */
 	regs->r1 = (unsigned long) frame;

 	/* Signal handler args: */
 	regs->r5 = signal; /* arg 0: signum */
 	regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
 	regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
 	/* Offset to handle microblaze rtid r14, 0 */
 	regs->pc = (unsigned long)ka->sa.sa_handler;

 	set_fs(USER_DS);

 	/* the tracer may want to single-step inside the handler */
 	if (test_thread_flag(TIF_SINGLESTEP))
 		ptrace_notify(SIGTRAP);

 #ifdef DEBUG_SIG
 	printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
 		current->comm, current->pid, frame, regs->pc);
 #endif

 	return;

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

 /* Handle restarting system calls */
 static inline void
 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 {
 	switch (regs->r3) {
 	case -ERESTART_RESTARTBLOCK:
 	case -ERESTARTNOHAND:
 		if (!has_handler)
 			goto do_restart;
 		regs->r3 = -EINTR;
 		break;
 	case -ERESTARTSYS:
 		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 			regs->r3 = -EINTR;
 			break;
 	}
 	/* fallthrough */
 	case -ERESTARTNOINTR:
 do_restart:
 		/* offset of 4 bytes to re-execute trap (brki) instruction */
 #ifndef CONFIG_MMU
 		regs->pc -= 4;
 #else
 		/* offset of 8 bytes required = 4 for rtbd
 		   offset, plus 4 for size of
 			"brki r14,8"
 		   instruction. */
 		regs->pc -= 8;
 #endif
 		break;
 	}
 }

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

 static int
 handle_signal(unsigned long sig, struct k_sigaction *ka,
 		siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
 {
 	/* Set up the stack frame */
 	if (ka->sa.sa_flags & SA_SIGINFO)
 		setup_rt_frame(sig, ka, info, oldset, regs);
 	else
 		setup_rt_frame(sig, ka, NULL, oldset, regs);

 	if (ka->sa.sa_flags & SA_ONESHOT)
 		ka->sa.sa_handler = SIG_DFL;

 	if (!(ka->sa.sa_flags & SA_NODEFER)) {
 		spin_lock_irq(&current->sighand->siglock);
 		sigorsets(&current->blocked,
 				&current->blocked, &ka->sa.sa_mask);
 		sigaddset(&current->blocked, sig);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
 	}
 	return 1;
 }

 /*
  * 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, int in_syscall)
 {
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;
 #ifdef DEBUG_SIG
 	printk(KERN_INFO "do signal: %p %p %d\n", regs, oldset, in_syscall);
 	printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
 			regs->r12, current_thread_info()->flags);
 #endif
 	/*
 	 * 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 (kernel_mode(regs))
 		return 1;

 	if (current_thread_info()->status & TS_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 (in_syscall)
 			handle_restart(regs, &ka, 1);
 		if (handle_signal(signr, &ka, &info, 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 TS_RESTORE_SIGMASK flag.
 			 */
 			current_thread_info()->status &=
 			    ~TS_RESTORE_SIGMASK;
 		}
 		return 1;
 	}

 	if (in_syscall)
 		handle_restart(regs, NULL, 0);

 	/*
 	 * If there's no signal to deliver, we just put the saved sigmask
 	 * back.
 	 */
 	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 	}

 	/* Did we come from a system call? */
 	return 0;
 }
	/*
	* Signal handling
	*
	* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
	* Copyright (C) 2008-2009 PetaLogix
	* Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
	* Copyright (C) 2001 NEC Corporation
	* Copyright (C) 2001 Miles Bader <miles@gnu.org>
	* Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
	* Copyright (C) 1991,1992 Linus Torvalds
	*
	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	*
	* This file was was derived from the sh version, arch/sh/kernel/signal.c
	*
	* 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.
	*/

	#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 <linux/personality.h>
	#include <linux/percpu.h>
	#include <linux/linkage.h>
	#include <asm/entry.h>
	#include <asm/ucontext.h>
	#include <linux/uaccess.h>
	#include <asm/pgtable.h>
	#include <asm/pgalloc.h>
	#include <linux/syscalls.h>
	#include <asm/cacheflush.h>
	#include <asm/syscalls.h>

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

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

	asmlinkage long
	sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	struct pt_regs *regs)
	{
	return do_sigaltstack(uss, uoss, regs->r1);
	}

	/*
	* Do a signal return; undo the signal stack.
	*/
	struct sigframe {
	struct sigcontext sc;
	unsigned long extramask[_NSIG_WORDS-1];
	unsigned long tramp[2]; /* signal trampoline */
	};

	struct rt_sigframe {
	struct siginfo info;
	struct ucontext uc;
	unsigned long tramp[2]; /* signal trampoline */
	};

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

	#define COPY(x) {err \|= __get_user(regs->x, &sc->regs.x); }
	COPY(r0);
	COPY(r1);
	COPY(r2); COPY(r3); COPY(r4); COPY(r5);
	COPY(r6); COPY(r7); COPY(r8); COPY(r9);
	COPY(r10); COPY(r11); COPY(r12); COPY(r13);
	COPY(r14); COPY(r15); COPY(r16); COPY(r17);
	COPY(r18); COPY(r19); COPY(r20); COPY(r21);
	COPY(r22); COPY(r23); COPY(r24); COPY(r25);
	COPY(r26); COPY(r27); COPY(r28); COPY(r29);
	COPY(r30); COPY(r31);
	COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
	#undef COPY

	*rval_p = regs->r3;

	return err;
	}

	asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
	{
	struct rt_sigframe __user *frame =
	(struct rt_sigframe __user *)(regs->r1);

	sigset_t set;
	int rval;

	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, &rval))
	goto badframe;

	/* It is more difficult to avoid calling this function than to
	call it and ignore errors. */
	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->r1))
	goto badframe;

	return rval;

	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;

	#define COPY(x) {err \|= __put_user(regs->x, &sc->regs.x); }
	COPY(r0);
	COPY(r1);
	COPY(r2); COPY(r3); COPY(r4); COPY(r5);
	COPY(r6); COPY(r7); COPY(r8); COPY(r9);
	COPY(r10); COPY(r11); COPY(r12); COPY(r13);
	COPY(r14); COPY(r15); COPY(r16); COPY(r17);
	COPY(r18); COPY(r19); COPY(r20); COPY(r21);
	COPY(r22); COPY(r23); COPY(r24); COPY(r25);
	COPY(r26); COPY(r27); COPY(r28); COPY(r29);
	COPY(r30); COPY(r31);
	COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
	#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, struct pt_regs regs, size_t frame_size)
	{
	/* Default to using normal stack */
	unsigned long sp = regs->r1;

	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp))
	sp = current->sas_ss_sp + current->sas_ss_size;

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

	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;
	unsigned long address = 0;
	#ifdef CONFIG_MMU
	pmd_t *pmdp;
	pte_t *ptep;
	#endif

	frame = get_sigframe(ka, regs, 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;

	if (info)
	err \|= copy_siginfo_to_user(&frame->info, info);

	/* Create the ucontext. */
	err \|= __put_user(0, &frame->uc.uc_flags);
	err \|= __put_user(NULL, &frame->uc.uc_link);
	err \|= __put_user((void __user *)current->sas_ss_sp,
	&frame->uc.uc_stack.ss_sp);
	err \|= __put_user(sas_ss_flags(regs->r1),
	&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));

	/* Set up to return from userspace. If provided, use a stub
	already in userspace. */
	/* minus 8 is offset to cater for "rtsd r15,8" */
	/* addi r12, r0, __NR_sigreturn */
	err \|= __put_user(0x31800000 \| __NR_rt_sigreturn ,
	frame->tramp + 0);
	/* brki r14, 0x8 */
	err \|= __put_user(0xb9cc0008, frame->tramp + 1);

	/* Return from sighandler will jump to the tramp.
	Negative 8 offset because return is rtsd r15, 8 */
	regs->r15 = ((unsigned long)frame->tramp)-8;

	address = ((unsigned long)frame->tramp);
	#ifdef CONFIG_MMU
	pmdp = pmd_offset(pud_offset(
	pgd_offset(current->mm, address),
	address), address);

	preempt_disable();
	ptep = pte_offset_map(pmdp, address);
	if (pte_present(*ptep)) {
	address = (unsigned long) page_address(pte_page(*ptep));
	/* MS: I need add offset in page */
	address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
	/* MS address is virtual */
	address = virt_to_phys(address);
	invalidate_icache_range(address, address + 8);
	flush_dcache_range(address, address + 8);
	}
	pte_unmap(ptep);
	preempt_enable();
	#else
	flush_icache_range(address, address + 8);
	flush_dcache_range(address, address + 8);
	#endif
	if (err)
	goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->r1 = (unsigned long) frame;

	/* Signal handler args: */
	regs->r5 = signal; /* arg 0: signum */
	regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
	regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
	/* Offset to handle microblaze rtid r14, 0 */
	regs->pc = (unsigned long)ka->sa.sa_handler;

	set_fs(USER_DS);

	/* the tracer may want to single-step inside the handler */
	if (test_thread_flag(TIF_SINGLESTEP))
	ptrace_notify(SIGTRAP);

	#ifdef DEBUG_SIG
	printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
	current->comm, current->pid, frame, regs->pc);
	#endif

	return;

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

	/* Handle restarting system calls */
	static inline void
	handle_restart(struct pt_regs regs, struct k_sigaction ka, int has_handler)
	{
	switch (regs->r3) {
	case -ERESTART_RESTARTBLOCK:
	case -ERESTARTNOHAND:
	if (!has_handler)
	goto do_restart;
	regs->r3 = -EINTR;
	break;
	case -ERESTARTSYS:
	if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
	regs->r3 = -EINTR;
	break;
	}
	/* fallthrough */
	case -ERESTARTNOINTR:
	do_restart:
	/* offset of 4 bytes to re-execute trap (brki) instruction */
	#ifndef CONFIG_MMU
	regs->pc -= 4;
	#else
	/* offset of 8 bytes required = 4 for rtbd
	offset, plus 4 for size of
	"brki r14,8"
	instruction. */
	regs->pc -= 8;
	#endif
	break;
	}
	}

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

	static int
	handle_signal(unsigned long sig, struct k_sigaction *ka,
	siginfo_t info, sigset_t oldset, struct pt_regs *regs)
	{
	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
	setup_rt_frame(sig, ka, info, oldset, regs);
	else
	setup_rt_frame(sig, ka, NULL, oldset, regs);

	if (ka->sa.sa_flags & SA_ONESHOT)
	ka->sa.sa_handler = SIG_DFL;

	if (!(ka->sa.sa_flags & SA_NODEFER)) {
	spin_lock_irq(&current->sighand->siglock);
	sigorsets(&current->blocked,
	&current->blocked, &ka->sa.sa_mask);
	sigaddset(&current->blocked, sig);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	}
	return 1;
	}

	/*
	* 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, int in_syscall)
	{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	#ifdef DEBUG_SIG
	printk(KERN_INFO "do signal: %p %p %d\n", regs, oldset, in_syscall);
	printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
	regs->r12, current_thread_info()->flags);
	#endif
	/*
	* 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 (kernel_mode(regs))
	return 1;

	if (current_thread_info()->status & TS_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 (in_syscall)
	handle_restart(regs, &ka, 1);
	if (handle_signal(signr, &ka, &info, 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 TS_RESTORE_SIGMASK flag.
	*/
	current_thread_info()->status &=
	~TS_RESTORE_SIGMASK;
	}
	return 1;
	}

	if (in_syscall)
	handle_restart(regs, NULL, 0);

	/*
	* If there's no signal to deliver, we just put the saved sigmask
	* back.
	*/
	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}

	/* Did we come from a system call? */
	return 0;
	}