arch/um/sys-i386/signal.c - fp2-dev/kernel/msm - Gitiles

 /*
  * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */

 #include "linux/ptrace.h"
 #include "asm/unistd.h"
 #include "asm/uaccess.h"
 #include "asm/ucontext.h"
 #include "frame_kern.h"
 #include "skas.h"

 void copy_sc(struct uml_pt_regs *regs, void *from)
 {
 	struct sigcontext *sc = from;

 	REGS_GS(regs->regs) = sc->gs;
 	REGS_FS(regs->regs) = sc->fs;
 	REGS_ES(regs->regs) = sc->es;
 	REGS_DS(regs->regs) = sc->ds;
 	REGS_EDI(regs->regs) = sc->edi;
 	REGS_ESI(regs->regs) = sc->esi;
 	REGS_EBP(regs->regs) = sc->ebp;
 	REGS_SP(regs->regs) = sc->esp;
 	REGS_EBX(regs->regs) = sc->ebx;
 	REGS_EDX(regs->regs) = sc->edx;
 	REGS_ECX(regs->regs) = sc->ecx;
 	REGS_EAX(regs->regs) = sc->eax;
 	REGS_IP(regs->regs) = sc->eip;
 	REGS_CS(regs->regs) = sc->cs;
 	REGS_EFLAGS(regs->regs) = sc->eflags;
 	REGS_SS(regs->regs) = sc->ss;
 }

 static int copy_sc_from_user(struct pt_regs *regs,
 			     struct sigcontext __user *from)
 {
  	struct sigcontext sc;
 	unsigned long fpregs[HOST_FP_SIZE];
 	int err;

 	err = copy_from_user(&sc, from, sizeof(sc));
 	err |= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs));
 	if (err)
 		return err;

 	copy_sc(&regs->regs, &sc);

 	err = restore_fp_registers(userspace_pid[0], fpregs);
 	if (err < 0) {
 	  	printk(KERN_ERR "copy_sc_from_user_skas - PTRACE_SETFPREGS "
 		       "failed, errno = %d\n", -err);
 		return err;
 	}

 	return 0;
 }

 static int copy_sc_to_user(struct sigcontext __user *to,
 			   struct _fpstate __user *to_fp, struct pt_regs *regs,
 			   unsigned long sp)
 {
 	struct sigcontext sc;
 	unsigned long fpregs[HOST_FP_SIZE];
 	struct faultinfo * fi = &current->thread.arch.faultinfo;
 	int err;

 	sc.gs = REGS_GS(regs->regs.regs);
 	sc.fs = REGS_FS(regs->regs.regs);
 	sc.es = REGS_ES(regs->regs.regs);
 	sc.ds = REGS_DS(regs->regs.regs);
 	sc.edi = REGS_EDI(regs->regs.regs);
 	sc.esi = REGS_ESI(regs->regs.regs);
 	sc.ebp = REGS_EBP(regs->regs.regs);
 	sc.esp = sp;
 	sc.ebx = REGS_EBX(regs->regs.regs);
 	sc.edx = REGS_EDX(regs->regs.regs);
 	sc.ecx = REGS_ECX(regs->regs.regs);
 	sc.eax = REGS_EAX(regs->regs.regs);
 	sc.eip = REGS_IP(regs->regs.regs);
 	sc.cs = REGS_CS(regs->regs.regs);
 	sc.eflags = REGS_EFLAGS(regs->regs.regs);
 	sc.esp_at_signal = regs->regs.regs[UESP];
 	sc.ss = regs->regs.regs[SS];
 	sc.cr2 = fi->cr2;
 	sc.err = fi->error_code;
 	sc.trapno = fi->trap_no;

 	err = save_fp_registers(userspace_pid[0], fpregs);
 	if (err < 0) {
 	  	printk(KERN_ERR "copy_sc_to_user_skas - PTRACE_GETFPREGS "
 		       "failed, errno = %d\n", err);
 		return 1;
 	}
 	to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
 	sc.fpstate = to_fp;

 	if (err)
 	  	return err;

 	return copy_to_user(to, &sc, sizeof(sc)) ||
 	       copy_to_user(to_fp, fpregs, sizeof(fpregs));
 }

 static int copy_ucontext_to_user(struct ucontext __user *uc,
 				 struct _fpstate __user *fp, sigset_t *set,
 				 unsigned long sp)
 {
 	int err = 0;

 	err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
 	err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
 	err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
 	err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
 	err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
 	return err;
 }

 struct sigframe
 {
 	char __user *pretcode;
 	int sig;
 	struct sigcontext sc;
 	struct _fpstate fpstate;
 	unsigned long extramask[_NSIG_WORDS-1];
 	char retcode[8];
 };

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

 int setup_signal_stack_sc(unsigned long stack_top, int sig,
 			  struct k_sigaction *ka, struct pt_regs *regs,
 			  sigset_t *mask)
 {
 	struct sigframe __user *frame;
 	void __user *restorer;
 	unsigned long save_sp = PT_REGS_SP(regs);
 	int err = 0;

 	/* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
 	stack_top = ((stack_top + 4) & -16UL) - 4;
 	frame = (struct sigframe __user *) stack_top - 1;
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return 1;

 	restorer = frame->retcode;
 	if (ka->sa.sa_flags & SA_RESTORER)
 		restorer = ka->sa.sa_restorer;

 	/* Update SP now because the page fault handler refuses to extend
 	 * the stack if the faulting address is too far below the current
 	 * SP, which frame now certainly is.  If there's an error, the original
 	 * value is restored on the way out.
 	 * When writing the sigcontext to the stack, we have to write the
 	 * original value, so that's passed to copy_sc_to_user, which does
 	 * the right thing with it.
 	 */
 	PT_REGS_SP(regs) = (unsigned long) frame;

 	err |= __put_user(restorer, &frame->pretcode);
 	err |= __put_user(sig, &frame->sig);
 	err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
 	err |= __put_user(mask->sig[0], &frame->sc.oldmask);
 	if (_NSIG_WORDS > 1)
 		err |= __copy_to_user(&frame->extramask, &mask->sig[1],
 				      sizeof(frame->extramask));

 	/*
 	 * This is popl %eax ; movl $,%eax ; int $0x80
 	 *
 	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
 	 * reasons and because gdb uses it as a signature to notice
 	 * signal handler stack frames.
 	 */
 	err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 	err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 	err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));

 	if (err)
 		goto err;

 	PT_REGS_SP(regs) = (unsigned long) frame;
 	PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 	PT_REGS_EAX(regs) = (unsigned long) sig;
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;

 	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 		ptrace_notify(SIGTRAP);
 	return 0;

 err:
 	PT_REGS_SP(regs) = save_sp;
 	return err;
 }

 int setup_signal_stack_si(unsigned long stack_top, int sig,
 			  struct k_sigaction *ka, struct pt_regs *regs,
 			  siginfo_t *info, sigset_t *mask)
 {
 	struct rt_sigframe __user *frame;
 	void __user *restorer;
 	unsigned long save_sp = PT_REGS_SP(regs);
 	int err = 0;

 	stack_top &= -8UL;
 	frame = (struct rt_sigframe __user *) stack_top - 1;
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return 1;

 	restorer = frame->retcode;
 	if (ka->sa.sa_flags & SA_RESTORER)
 		restorer = ka->sa.sa_restorer;

 	/* See comment above about why this is here */
 	PT_REGS_SP(regs) = (unsigned long) frame;

 	err |= __put_user(restorer, &frame->pretcode);
 	err |= __put_user(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);
 	err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
 				     save_sp);

 	/*
 	 * This is movl $,%eax ; int $0x80
 	 *
 	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
 	 * reasons and because gdb uses it as a signature to notice
 	 * signal handler stack frames.
 	 */
 	err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 	err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 	err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));

 	if (err)
 		goto err;

 	PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 	PT_REGS_EAX(regs) = (unsigned long) sig;
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;

 	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 		ptrace_notify(SIGTRAP);
 	return 0;

 err:
 	PT_REGS_SP(regs) = save_sp;
 	return err;
 }

 long sys_sigreturn(struct pt_regs regs)
 {
 	unsigned long sp = PT_REGS_SP(&current->thread.regs);
 	struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
 	sigset_t set;
 	struct sigcontext __user *sc = &frame->sc;
 	unsigned long __user *oldmask = &sc->oldmask;
 	unsigned long __user *extramask = frame->extramask;
 	int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);

 	if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
 	    copy_from_user(&set.sig[1], extramask, sig_size))
 		goto segfault;

 	sigdelsetmask(&set, ~_BLOCKABLE);

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

 	if (copy_sc_from_user(&current->thread.regs, sc))
 		goto segfault;

 	/* Avoid ERESTART handling */
 	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 	return PT_REGS_SYSCALL_RET(&current->thread.regs);

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

 long sys_rt_sigreturn(struct pt_regs regs)
 {
 	unsigned long sp = PT_REGS_SP(&current->thread.regs);
 	struct rt_sigframe __user *frame =
 		(struct rt_sigframe __user *) (sp - 4);
 	sigset_t set;
 	struct ucontext __user *uc = &frame->uc;
 	int sig_size = _NSIG_WORDS * sizeof(unsigned long);

 	if (copy_from_user(&set, &uc->uc_sigmask, sig_size))
 		goto segfault;

 	sigdelsetmask(&set, ~_BLOCKABLE);

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

 	if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
 		goto segfault;

 	/* Avoid ERESTART handling */
 	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 	return PT_REGS_SYSCALL_RET(&current->thread.regs);

  segfault:
 	force_sig(SIGSEGV, current);
 	return 0;
 }
	/*
	* Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
	* Licensed under the GPL
	*/

	#include "linux/ptrace.h"
	#include "asm/unistd.h"
	#include "asm/uaccess.h"
	#include "asm/ucontext.h"
	#include "frame_kern.h"
	#include "skas.h"

	void copy_sc(struct uml_pt_regs regs, void from)
	{
	struct sigcontext *sc = from;

	REGS_GS(regs->regs) = sc->gs;
	REGS_FS(regs->regs) = sc->fs;
	REGS_ES(regs->regs) = sc->es;
	REGS_DS(regs->regs) = sc->ds;
	REGS_EDI(regs->regs) = sc->edi;
	REGS_ESI(regs->regs) = sc->esi;
	REGS_EBP(regs->regs) = sc->ebp;
	REGS_SP(regs->regs) = sc->esp;
	REGS_EBX(regs->regs) = sc->ebx;
	REGS_EDX(regs->regs) = sc->edx;
	REGS_ECX(regs->regs) = sc->ecx;
	REGS_EAX(regs->regs) = sc->eax;
	REGS_IP(regs->regs) = sc->eip;
	REGS_CS(regs->regs) = sc->cs;
	REGS_EFLAGS(regs->regs) = sc->eflags;
	REGS_SS(regs->regs) = sc->ss;
	}

	static int copy_sc_from_user(struct pt_regs *regs,
	struct sigcontext __user *from)
	{
	struct sigcontext sc;
	unsigned long fpregs[HOST_FP_SIZE];
	int err;

	err = copy_from_user(&sc, from, sizeof(sc));
	err \|= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs));
	if (err)
	return err;

	copy_sc(&regs->regs, &sc);

	err = restore_fp_registers(userspace_pid[0], fpregs);
	if (err < 0) {
	printk(KERN_ERR "copy_sc_from_user_skas - PTRACE_SETFPREGS "
	"failed, errno = %d\n", -err);
	return err;
	}

	return 0;
	}

	static int copy_sc_to_user(struct sigcontext __user *to,
	struct _fpstate __user to_fp, struct pt_regs regs,
	unsigned long sp)
	{
	struct sigcontext sc;
	unsigned long fpregs[HOST_FP_SIZE];
	struct faultinfo * fi = &current->thread.arch.faultinfo;
	int err;

	sc.gs = REGS_GS(regs->regs.regs);
	sc.fs = REGS_FS(regs->regs.regs);
	sc.es = REGS_ES(regs->regs.regs);
	sc.ds = REGS_DS(regs->regs.regs);
	sc.edi = REGS_EDI(regs->regs.regs);
	sc.esi = REGS_ESI(regs->regs.regs);
	sc.ebp = REGS_EBP(regs->regs.regs);
	sc.esp = sp;
	sc.ebx = REGS_EBX(regs->regs.regs);
	sc.edx = REGS_EDX(regs->regs.regs);
	sc.ecx = REGS_ECX(regs->regs.regs);
	sc.eax = REGS_EAX(regs->regs.regs);
	sc.eip = REGS_IP(regs->regs.regs);
	sc.cs = REGS_CS(regs->regs.regs);
	sc.eflags = REGS_EFLAGS(regs->regs.regs);
	sc.esp_at_signal = regs->regs.regs[UESP];
	sc.ss = regs->regs.regs[SS];
	sc.cr2 = fi->cr2;
	sc.err = fi->error_code;
	sc.trapno = fi->trap_no;

	err = save_fp_registers(userspace_pid[0], fpregs);
	if (err < 0) {
	printk(KERN_ERR "copy_sc_to_user_skas - PTRACE_GETFPREGS "
	"failed, errno = %d\n", err);
	return 1;
	}
	to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
	sc.fpstate = to_fp;

	if (err)
	return err;

	return copy_to_user(to, &sc, sizeof(sc)) \|\|
	copy_to_user(to_fp, fpregs, sizeof(fpregs));
	}

	static int copy_ucontext_to_user(struct ucontext __user *uc,
	struct _fpstate __user fp, sigset_t set,
	unsigned long sp)
	{
	int err = 0;

	err \|= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
	err \|= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
	err \|= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
	err \|= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
	err \|= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
	return err;
	}

	struct sigframe
	{
	char __user *pretcode;
	int sig;
	struct sigcontext sc;
	struct _fpstate fpstate;
	unsigned long extramask[_NSIG_WORDS-1];
	char retcode[8];
	};

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

	int setup_signal_stack_sc(unsigned long stack_top, int sig,
	struct k_sigaction ka, struct pt_regs regs,
	sigset_t *mask)
	{
	struct sigframe __user *frame;
	void __user *restorer;
	unsigned long save_sp = PT_REGS_SP(regs);
	int err = 0;

	/* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
	stack_top = ((stack_top + 4) & -16UL) - 4;
	frame = (struct sigframe __user *) stack_top - 1;
	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	return 1;

	restorer = frame->retcode;
	if (ka->sa.sa_flags & SA_RESTORER)
	restorer = ka->sa.sa_restorer;

	/* Update SP now because the page fault handler refuses to extend
	* the stack if the faulting address is too far below the current
	* SP, which frame now certainly is. If there's an error, the original
	* value is restored on the way out.
	* When writing the sigcontext to the stack, we have to write the
	* original value, so that's passed to copy_sc_to_user, which does
	* the right thing with it.
	*/
	PT_REGS_SP(regs) = (unsigned long) frame;

	err \|= __put_user(restorer, &frame->pretcode);
	err \|= __put_user(sig, &frame->sig);
	err \|= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
	err \|= __put_user(mask->sig[0], &frame->sc.oldmask);
	if (_NSIG_WORDS > 1)
	err \|= __copy_to_user(&frame->extramask, &mask->sig[1],
	sizeof(frame->extramask));

	/*
	* This is popl %eax ; movl $,%eax ; int $0x80
	*
	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	* reasons and because gdb uses it as a signature to notice
	* signal handler stack frames.
	*/
	err \|= __put_user(0xb858, (short __user *)(frame->retcode+0));
	err \|= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
	err \|= __put_user(0x80cd, (short __user *)(frame->retcode+6));

	if (err)
	goto err;

	PT_REGS_SP(regs) = (unsigned long) frame;
	PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
	PT_REGS_EAX(regs) = (unsigned long) sig;
	PT_REGS_EDX(regs) = (unsigned long) 0;
	PT_REGS_ECX(regs) = (unsigned long) 0;

	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
	ptrace_notify(SIGTRAP);
	return 0;

	err:
	PT_REGS_SP(regs) = save_sp;
	return err;
	}

	int setup_signal_stack_si(unsigned long stack_top, int sig,
	struct k_sigaction ka, struct pt_regs regs,
	siginfo_t info, sigset_t mask)
	{
	struct rt_sigframe __user *frame;
	void __user *restorer;
	unsigned long save_sp = PT_REGS_SP(regs);
	int err = 0;

	stack_top &= -8UL;
	frame = (struct rt_sigframe __user *) stack_top - 1;
	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	return 1;

	restorer = frame->retcode;
	if (ka->sa.sa_flags & SA_RESTORER)
	restorer = ka->sa.sa_restorer;

	/* See comment above about why this is here */
	PT_REGS_SP(regs) = (unsigned long) frame;

	err \|= __put_user(restorer, &frame->pretcode);
	err \|= __put_user(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);
	err \|= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
	save_sp);

	/*
	* This is movl $,%eax ; int $0x80
	*
	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	* reasons and because gdb uses it as a signature to notice
	* signal handler stack frames.
	*/
	err \|= __put_user(0xb8, (char __user *)(frame->retcode+0));
	err \|= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
	err \|= __put_user(0x80cd, (short __user *)(frame->retcode+5));

	if (err)
	goto err;

	PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
	PT_REGS_EAX(regs) = (unsigned long) sig;
	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;

	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
	ptrace_notify(SIGTRAP);
	return 0;

	err:
	PT_REGS_SP(regs) = save_sp;
	return err;
	}

	long sys_sigreturn(struct pt_regs regs)
	{
	unsigned long sp = PT_REGS_SP(&current->thread.regs);
	struct sigframe __user frame = (struct sigframe __user )(sp - 8);
	sigset_t set;
	struct sigcontext __user *sc = &frame->sc;
	unsigned long __user *oldmask = &sc->oldmask;
	unsigned long __user *extramask = frame->extramask;
	int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);

	if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) \|\|
	copy_from_user(&set.sig[1], extramask, sig_size))
	goto segfault;

	sigdelsetmask(&set, ~_BLOCKABLE);

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

	if (copy_sc_from_user(&current->thread.regs, sc))
	goto segfault;

	/* Avoid ERESTART handling */
	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
	return PT_REGS_SYSCALL_RET(&current->thread.regs);

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

	long sys_rt_sigreturn(struct pt_regs regs)
	{
	unsigned long sp = PT_REGS_SP(&current->thread.regs);
	struct rt_sigframe __user *frame =
	(struct rt_sigframe __user *) (sp - 4);
	sigset_t set;
	struct ucontext __user *uc = &frame->uc;
	int sig_size = _NSIG_WORDS * sizeof(unsigned long);

	if (copy_from_user(&set, &uc->uc_sigmask, sig_size))
	goto segfault;

	sigdelsetmask(&set, ~_BLOCKABLE);

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

	if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
	goto segfault;

	/* Avoid ERESTART handling */
	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
	return PT_REGS_SYSCALL_RET(&current->thread.regs);

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