arch/s390/kernel/signal.c - third_party/linux - Git at Google

 /*
  *  arch/s390/kernel/signal.c
  *
  *  S390 version
  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
  *
  *    Based on Intel version
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  */

 #include <linux/config.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/smp_lock.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/tty.h>
 #include <linux/personality.h>
 #include <linux/binfmts.h>
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
 #include <asm/lowcore.h>

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


 typedef struct
 {
 	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
 	struct sigcontext sc;
 	_sigregs sregs;
 	int signo;
 	__u8 retcode[S390_SYSCALL_SIZE];
 } sigframe;

 typedef struct
 {
 	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
 	__u8 retcode[S390_SYSCALL_SIZE];
 	struct siginfo info;
 	struct ucontext uc;
 } rt_sigframe;

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

 /*
  * Atomically swap in the new signal mask, and wait for a signal.
  */
 asmlinkage int
 sys_sigsuspend(struct pt_regs * regs, int history0, int history1,
 	       old_sigset_t mask)
 {
 	sigset_t saveset;

 	mask &= _BLOCKABLE;
 	spin_lock_irq(&current->sighand->siglock);
 	saveset = current->blocked;
 	siginitset(&current->blocked, mask);
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 	regs->gprs[2] = -EINTR;

 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule();
 		if (do_signal(regs, &saveset))
 			return -EINTR;
 	}
 }

 asmlinkage long
 sys_rt_sigsuspend(struct pt_regs *regs, sigset_t __user *unewset,
 						size_t sigsetsize)
 {
 	sigset_t saveset, newset;

 	/* XXX: Don't preclude handling different sized sigset_t's.  */
 	if (sigsetsize != sizeof(sigset_t))
 		return -EINVAL;

 	if (copy_from_user(&newset, unewset, sizeof(newset)))
 		return -EFAULT;
 	sigdelsetmask(&newset, ~_BLOCKABLE);

 	spin_lock_irq(&current->sighand->siglock);
 	saveset = current->blocked;
 	current->blocked = newset;
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 	regs->gprs[2] = -EINTR;

 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule();
 		if (do_signal(regs, &saveset))
 			return -EINTR;
 	}
 }

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

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

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

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

 	return ret;
 }

 asmlinkage long
 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 					struct pt_regs *regs)
 {
 	return do_sigaltstack(uss, uoss, regs->gprs[15]);
 }


 /* Returns non-zero on fault. */
 static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 {
 	unsigned long old_mask = regs->psw.mask;
 	int err;

 	save_access_regs(current->thread.acrs);

 	/* Copy a 'clean' PSW mask to the user to avoid leaking
 	   information about whether PER is currently on.  */
 	regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
 	err = __copy_to_user(&sregs->regs.psw, &regs->psw,
 			     sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
 	regs->psw.mask = old_mask;
 	if (err != 0)
 		return err;
 	err = __copy_to_user(&sregs->regs.acrs, current->thread.acrs,
 			     sizeof(sregs->regs.acrs));
 	if (err != 0)
 		return err;
 	/*
 	 * We have to store the fp registers to current->thread.fp_regs
 	 * to merge them with the emulated registers.
 	 */
 	save_fp_regs(&current->thread.fp_regs);
 	return __copy_to_user(&sregs->fpregs, &current->thread.fp_regs,
 			      sizeof(s390_fp_regs));
 }

 /* Returns positive number on error */
 static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 {
 	unsigned long old_mask = regs->psw.mask;
 	int err;

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

 	err = __copy_from_user(&regs->psw, &sregs->regs.psw,
 			       sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
 	regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask);
 	regs->psw.addr |= PSW_ADDR_AMODE;
 	if (err)
 		return err;
 	err = __copy_from_user(&current->thread.acrs, &sregs->regs.acrs,
 			       sizeof(sregs->regs.acrs));
 	if (err)
 		return err;
 	restore_access_regs(current->thread.acrs);

 	err = __copy_from_user(&current->thread.fp_regs, &sregs->fpregs,
 			       sizeof(s390_fp_regs));
 	current->thread.fp_regs.fpc &= FPC_VALID_MASK;
 	if (err)
 		return err;

 	restore_fp_regs(&current->thread.fp_regs);
 	regs->trap = -1;	/* disable syscall checks */
 	return 0;
 }

 asmlinkage long sys_sigreturn(struct pt_regs *regs)
 {
 	sigframe __user *frame = (sigframe __user *)regs->gprs[15];
 	sigset_t set;

 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 		goto badframe;
 	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
 		goto badframe;

 	sigdelsetmask(&set, ~_BLOCKABLE);
 	spin_lock_irq(&current->sighand->siglock);
 	current->blocked = set;
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);

 	if (restore_sigregs(regs, &frame->sregs))
 		goto badframe;

 	return regs->gprs[2];

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

 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 {
 	rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
 	sigset_t set;

 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 		goto badframe;
 	if (__copy_from_user(&set.sig, &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_sigregs(regs, &frame->uc.uc_mcontext))
 		goto badframe;

 	/* It is more difficult to avoid calling this function than to
 	   call it and ignore errors.  */
 	do_sigaltstack(&frame->uc.uc_stack, NULL, regs->gprs[15]);
 	return regs->gprs[2];

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

 /*
  * Set up a signal frame.
  */


 /*
  * Determine which stack to use..
  */
 static inline void __user *
 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 {
 	unsigned long sp;

 	/* Default to using normal stack */
 	sp = regs->gprs[15];

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

 	/* This is the legacy signal stack switching. */
 	else if (!user_mode(regs) &&
 		 !(ka->sa.sa_flags & SA_RESTORER) &&
 		 ka->sa.sa_restorer) {
 		sp = (unsigned long) ka->sa.sa_restorer;
 	}

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

 static inline int map_signal(int sig)
 {
 	if (current_thread_info()->exec_domain
 	    && current_thread_info()->exec_domain->signal_invmap
 	    && sig < 32)
 		return current_thread_info()->exec_domain->signal_invmap[sig];
 	else
 		return sig;
 }

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

 	frame = get_sigframe(ka, regs, sizeof(sigframe));
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
 		goto give_sigsegv;

 	if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
 		goto give_sigsegv;

 	if (save_sigregs(regs, &frame->sregs))
 		goto give_sigsegv;
 	if (__put_user(&frame->sregs, &frame->sc.sregs))
 		goto give_sigsegv;

 	/* Set up to return from userspace.  If provided, use a stub
 	   already in userspace.  */
 	if (ka->sa.sa_flags & SA_RESTORER) {
                 regs->gprs[14] = (unsigned long)
 			ka->sa.sa_restorer | PSW_ADDR_AMODE;
 	} else {
                 regs->gprs[14] = (unsigned long)
 			frame->retcode | PSW_ADDR_AMODE;
 		if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
 	                       (u16 __user *)(frame->retcode)))
 			goto give_sigsegv;
 	}

 	/* Set up backchain. */
 	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
 		goto give_sigsegv;

 	/* Set up registers for signal handler */
 	regs->gprs[15] = (unsigned long) frame;
 	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;

 	regs->gprs[2] = map_signal(sig);
 	regs->gprs[3] = (unsigned long) &frame->sc;

 	/* We forgot to include these in the sigcontext.
 	   To avoid breaking binary compatibility, they are passed as args. */
 	regs->gprs[4] = current->thread.trap_no;
 	regs->gprs[5] = current->thread.prot_addr;

 	/* Place signal number on stack to allow backtrace from handler.  */
 	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
 		goto give_sigsegv;
 	return;

 give_sigsegv:
 	force_sigsegv(sig, current);
 }

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

 	frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
 		goto give_sigsegv;

 	if (copy_siginfo_to_user(&frame->info, info))
 		goto give_sigsegv;

 	/* Create the ucontext.  */
 	err |= __put_user(0, &frame->uc.uc_flags);
 	err |= __put_user(0, &frame->uc.uc_link);
 	err |= __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 	err |= __put_user(sas_ss_flags(regs->gprs[15]),
 			  &frame->uc.uc_stack.ss_flags);
 	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 	err |= save_sigregs(regs, &frame->uc.uc_mcontext);
 	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) {
                 regs->gprs[14] = (unsigned long)
 			ka->sa.sa_restorer | PSW_ADDR_AMODE;
 	} else {
                 regs->gprs[14] = (unsigned long)
 			frame->retcode | PSW_ADDR_AMODE;
 		err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
 	                          (u16 __user *)(frame->retcode));
 	}

 	/* Set up backchain. */
 	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
 		goto give_sigsegv;

 	/* Set up registers for signal handler */
 	regs->gprs[15] = (unsigned long) frame;
 	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;

 	regs->gprs[2] = map_signal(sig);
 	regs->gprs[3] = (unsigned long) &frame->info;
 	regs->gprs[4] = (unsigned long) &frame->uc;
 	return;

 give_sigsegv:
 	force_sigsegv(sig, current);
 }

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

 static void
 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_frame(sig, ka, oldset, regs);

 	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);
 	}
 }

 /*
  * 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)
 {
 	unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;

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

 	if (!oldset)
 		oldset = &current->blocked;

 	/* Are we from a system call? */
 	if (regs->trap == __LC_SVC_OLD_PSW) {
 		continue_addr = regs->psw.addr;
 		restart_addr = continue_addr - regs->ilc;
 		retval = regs->gprs[2];

 		/* Prepare for system call restart.  We do this here so that a
 		   debugger will see the already changed PSW. */
 		if (retval == -ERESTARTNOHAND ||
 		    retval == -ERESTARTSYS ||
 		    retval == -ERESTARTNOINTR) {
 			regs->gprs[2] = regs->orig_gpr2;
 			regs->psw.addr = restart_addr;
 		} else if (retval == -ERESTART_RESTARTBLOCK) {
 			regs->gprs[2] = -EINTR;
 		}
 	}

 	/* Get signal to deliver.  When running under ptrace, at this point
 	   the debugger may change all our registers ... */
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

 	/* Depending on the signal settings we may need to revert the
 	   decision to restart the system call. */
 	if (signr > 0 && regs->psw.addr == restart_addr) {
 		if (retval == -ERESTARTNOHAND
 		    || (retval == -ERESTARTSYS
 			 && !(current->sighand->action[signr-1].sa.sa_flags
 			      & SA_RESTART))) {
 			regs->gprs[2] = -EINTR;
 			regs->psw.addr = continue_addr;
 		}
 	}

 	if (signr > 0) {
 		/* Whee!  Actually deliver the signal.  */
 #ifdef CONFIG_S390_SUPPORT
 		if (test_thread_flag(TIF_31BIT)) {
 			extern void handle_signal32(unsigned long sig,
 						    struct k_sigaction *ka,
 						    siginfo_t *info,
 						    sigset_t *oldset,
 						    struct pt_regs *regs);
 			handle_signal32(signr, &ka, &info, oldset, regs);
 			return 1;
 	        }
 #endif
 		handle_signal(signr, &ka, &info, oldset, regs);
 		return 1;
 	}

 	/* Restart a different system call. */
 	if (retval == -ERESTART_RESTARTBLOCK
 	    && regs->psw.addr == continue_addr) {
 		regs->gprs[2] = __NR_restart_syscall;
 		set_thread_flag(TIF_RESTART_SVC);
 	}
 	return 0;
 }
	/*
	* arch/s390/kernel/signal.c
	*
	* S390 version
	* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
	* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
	*
	* Based on Intel version
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*
	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	*/

	#include <linux/config.h>
	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/smp.h>
	#include <linux/smp_lock.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/tty.h>
	#include <linux/personality.h>
	#include <linux/binfmts.h>
	#include <asm/ucontext.h>
	#include <asm/uaccess.h>
	#include <asm/lowcore.h>

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


	typedef struct
	{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	struct sigcontext sc;
	_sigregs sregs;
	int signo;
	__u8 retcode[S390_SYSCALL_SIZE];
	} sigframe;

	typedef struct
	{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	__u8 retcode[S390_SYSCALL_SIZE];
	struct siginfo info;
	struct ucontext uc;
	} rt_sigframe;

	int do_signal(struct pt_regs regs, sigset_t oldset);

	/*
	* Atomically swap in the new signal mask, and wait for a signal.
	*/
	asmlinkage int
	sys_sigsuspend(struct pt_regs * regs, int history0, int history1,
	old_sigset_t mask)
	{
	sigset_t saveset;

	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	regs->gprs[2] = -EINTR;

	while (1) {
	set_current_state(TASK_INTERRUPTIBLE);
	schedule();
	if (do_signal(regs, &saveset))
	return -EINTR;
	}
	}

	asmlinkage long
	sys_rt_sigsuspend(struct pt_regs regs, sigset_t __user unewset,
	size_t sigsetsize)
	{
	sigset_t saveset, newset;

	/* XXX: Don't preclude handling different sized sigset_t's. */
	if (sigsetsize != sizeof(sigset_t))
	return -EINVAL;

	if (copy_from_user(&newset, unewset, sizeof(newset)))
	return -EFAULT;
	sigdelsetmask(&newset, ~_BLOCKABLE);

	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	regs->gprs[2] = -EINTR;

	while (1) {
	set_current_state(TASK_INTERRUPTIBLE);
	schedule();
	if (do_signal(regs, &saveset))
	return -EINTR;
	}
	}

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

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

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

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

	return ret;
	}

	asmlinkage long
	sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	struct pt_regs *regs)
	{
	return do_sigaltstack(uss, uoss, regs->gprs[15]);
	}



	/* Returns non-zero on fault. */
	static int save_sigregs(struct pt_regs regs, _sigregs __user sregs)
	{
	unsigned long old_mask = regs->psw.mask;
	int err;

	save_access_regs(current->thread.acrs);

	/* Copy a 'clean' PSW mask to the user to avoid leaking
	information about whether PER is currently on. */
	regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
	err = __copy_to_user(&sregs->regs.psw, &regs->psw,
	sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
	regs->psw.mask = old_mask;
	if (err != 0)
	return err;
	err = __copy_to_user(&sregs->regs.acrs, current->thread.acrs,
	sizeof(sregs->regs.acrs));
	if (err != 0)
	return err;
	/*
	* We have to store the fp registers to current->thread.fp_regs
	* to merge them with the emulated registers.
	*/
	save_fp_regs(&current->thread.fp_regs);
	return __copy_to_user(&sregs->fpregs, &current->thread.fp_regs,
	sizeof(s390_fp_regs));
	}

	/* Returns positive number on error */
	static int restore_sigregs(struct pt_regs regs, _sigregs __user sregs)
	{
	unsigned long old_mask = regs->psw.mask;
	int err;

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

	err = __copy_from_user(&regs->psw, &sregs->regs.psw,
	sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
	regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask);
	regs->psw.addr \|= PSW_ADDR_AMODE;
	if (err)
	return err;
	err = __copy_from_user(&current->thread.acrs, &sregs->regs.acrs,
	sizeof(sregs->regs.acrs));
	if (err)
	return err;
	restore_access_regs(current->thread.acrs);

	err = __copy_from_user(&current->thread.fp_regs, &sregs->fpregs,
	sizeof(s390_fp_regs));
	current->thread.fp_regs.fpc &= FPC_VALID_MASK;
	if (err)
	return err;

	restore_fp_regs(&current->thread.fp_regs);
	regs->trap = -1; /* disable syscall checks */
	return 0;
	}

	asmlinkage long sys_sigreturn(struct pt_regs *regs)
	{
	sigframe __user frame = (sigframe __user )regs->gprs[15];
	sigset_t set;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	goto badframe;
	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
	goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigregs(regs, &frame->sregs))
	goto badframe;

	return regs->gprs[2];

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

	asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
	{
	rt_sigframe __user frame = (rt_sigframe __user )regs->gprs[15];
	sigset_t set;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	goto badframe;
	if (__copy_from_user(&set.sig, &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_sigregs(regs, &frame->uc.uc_mcontext))
	goto badframe;

	/* It is more difficult to avoid calling this function than to
	call it and ignore errors. */
	do_sigaltstack(&frame->uc.uc_stack, NULL, regs->gprs[15]);
	return regs->gprs[2];

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

	/*
	* Set up a signal frame.
	*/


	/*
	* Determine which stack to use..
	*/
	static inline void __user *
	get_sigframe(struct k_sigaction ka, struct pt_regs regs, size_t frame_size)
	{
	unsigned long sp;

	/* Default to using normal stack */
	sp = regs->gprs[15];

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

	/* This is the legacy signal stack switching. */
	else if (!user_mode(regs) &&
	!(ka->sa.sa_flags & SA_RESTORER) &&
	ka->sa.sa_restorer) {
	sp = (unsigned long) ka->sa.sa_restorer;
	}

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

	static inline int map_signal(int sig)
	{
	if (current_thread_info()->exec_domain
	&& current_thread_info()->exec_domain->signal_invmap
	&& sig < 32)
	return current_thread_info()->exec_domain->signal_invmap[sig];
	else
	return sig;
	}

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

	frame = get_sigframe(ka, regs, sizeof(sigframe));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
	goto give_sigsegv;

	if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
	goto give_sigsegv;

	if (save_sigregs(regs, &frame->sregs))
	goto give_sigsegv;
	if (__put_user(&frame->sregs, &frame->sc.sregs))
	goto give_sigsegv;

	/* Set up to return from userspace. If provided, use a stub
	already in userspace. */
	if (ka->sa.sa_flags & SA_RESTORER) {
	regs->gprs[14] = (unsigned long)
	ka->sa.sa_restorer \| PSW_ADDR_AMODE;
	} else {
	regs->gprs[14] = (unsigned long)
	frame->retcode \| PSW_ADDR_AMODE;
	if (__put_user(S390_SYSCALL_OPCODE \| __NR_sigreturn,
	(u16 __user *)(frame->retcode)))
	goto give_sigsegv;
	}

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
	goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (unsigned long) frame;
	regs->psw.addr = (unsigned long) ka->sa.sa_handler \| PSW_ADDR_AMODE;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (unsigned long) &frame->sc;

	/* We forgot to include these in the sigcontext.
	To avoid breaking binary compatibility, they are passed as args. */
	regs->gprs[4] = current->thread.trap_no;
	regs->gprs[5] = current->thread.prot_addr;

	/* Place signal number on stack to allow backtrace from handler. */
	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
	goto give_sigsegv;
	return;

	give_sigsegv:
	force_sigsegv(sig, current);
	}

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

	frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
	goto give_sigsegv;

	if (copy_siginfo_to_user(&frame->info, info))
	goto give_sigsegv;

	/* Create the ucontext. */
	err \|= __put_user(0, &frame->uc.uc_flags);
	err \|= __put_user(0, &frame->uc.uc_link);
	err \|= __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err \|= __put_user(sas_ss_flags(regs->gprs[15]),
	&frame->uc.uc_stack.ss_flags);
	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err \|= save_sigregs(regs, &frame->uc.uc_mcontext);
	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) {
	regs->gprs[14] = (unsigned long)
	ka->sa.sa_restorer \| PSW_ADDR_AMODE;
	} else {
	regs->gprs[14] = (unsigned long)
	frame->retcode \| PSW_ADDR_AMODE;
	err \|= __put_user(S390_SYSCALL_OPCODE \| __NR_rt_sigreturn,
	(u16 __user *)(frame->retcode));
	}

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
	goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (unsigned long) frame;
	regs->psw.addr = (unsigned long) ka->sa.sa_handler \| PSW_ADDR_AMODE;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (unsigned long) &frame->info;
	regs->gprs[4] = (unsigned long) &frame->uc;
	return;

	give_sigsegv:
	force_sigsegv(sig, current);
	}

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

	static void
	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_frame(sig, ka, oldset, regs);

	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);
	}
	}

	/*
	* 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)
	{
	unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
	siginfo_t info;
	int signr;
	struct k_sigaction ka;

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

	if (!oldset)
	oldset = &current->blocked;

	/* Are we from a system call? */
	if (regs->trap == __LC_SVC_OLD_PSW) {
	continue_addr = regs->psw.addr;
	restart_addr = continue_addr - regs->ilc;
	retval = regs->gprs[2];

	/* Prepare for system call restart. We do this here so that a
	debugger will see the already changed PSW. */
	if (retval == -ERESTARTNOHAND \|\|
	retval == -ERESTARTSYS \|\|
	retval == -ERESTARTNOINTR) {
	regs->gprs[2] = regs->orig_gpr2;
	regs->psw.addr = restart_addr;
	} else if (retval == -ERESTART_RESTARTBLOCK) {
	regs->gprs[2] = -EINTR;
	}
	}

	/* Get signal to deliver. When running under ptrace, at this point
	the debugger may change all our registers ... */
	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	/* Depending on the signal settings we may need to revert the
	decision to restart the system call. */
	if (signr > 0 && regs->psw.addr == restart_addr) {
	if (retval == -ERESTARTNOHAND
	\|\| (retval == -ERESTARTSYS
	&& !(current->sighand->action[signr-1].sa.sa_flags
	& SA_RESTART))) {
	regs->gprs[2] = -EINTR;
	regs->psw.addr = continue_addr;
	}
	}

	if (signr > 0) {
	/* Whee! Actually deliver the signal. */
	#ifdef CONFIG_S390_SUPPORT
	if (test_thread_flag(TIF_31BIT)) {
	extern void handle_signal32(unsigned long sig,
	struct k_sigaction *ka,
	siginfo_t *info,
	sigset_t *oldset,
	struct pt_regs *regs);
	handle_signal32(signr, &ka, &info, oldset, regs);
	return 1;
	}
	#endif
	handle_signal(signr, &ka, &info, oldset, regs);
	return 1;
	}

	/* Restart a different system call. */
	if (retval == -ERESTART_RESTARTBLOCK
	&& regs->psw.addr == continue_addr) {
	regs->gprs[2] = __NR_restart_syscall;
	set_thread_flag(TIF_RESTART_SVC);
	}
	return 0;
	}