arch/s390/kernel/signal.c - arm/linux-arm64-legacy - Git at Google

 /*
  *    Copyright IBM Corp. 1999, 2006
  *    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/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/tty.h>
 #include <linux/personality.h>
 #include <linux/binfmts.h>
 #include <linux/tracehook.h>
 #include <linux/syscalls.h>
 #include <linux/compat.h>
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
 #include <asm/lowcore.h>
 #include <asm/switch_to.h>
 #include "entry.h"

 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;

 /* Returns non-zero on fault. */
 static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 {
 	_sigregs user_sregs;

 	save_access_regs(current->thread.acrs);

 	/* Copy a 'clean' PSW mask to the user to avoid leaking
 	   information about whether PER is currently on.  */
 	user_sregs.regs.psw.mask = PSW_USER_BITS |
 		(regs->psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
 	user_sregs.regs.psw.addr = regs->psw.addr;
 	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
 	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
 	       sizeof(user_sregs.regs.acrs));
 	/*
 	 * We have to store the fp registers to current->thread.fp_regs
 	 * to merge them with the emulated registers.
 	 */
 	save_fp_ctl(&current->thread.fp_regs.fpc);
 	save_fp_regs(current->thread.fp_regs.fprs);
 	memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
 	       sizeof(user_sregs.fpregs));
 	if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
 		return -EFAULT;
 	return 0;
 }

 static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 {
 	_sigregs user_sregs;

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

 	if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
 		return -EFAULT;

 	if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
 		return -EINVAL;

 	/* Loading the floating-point-control word can fail. Do that first. */
 	if (restore_fp_ctl(&user_sregs.fpregs.fpc))
 		return -EINVAL;

 	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
 	regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
 		(user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
 	/* Check for invalid user address space control. */
 	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
 		regs->psw.mask = PSW_ASC_PRIMARY |
 			(regs->psw.mask & ~PSW_MASK_ASC);
 	/* Check for invalid amode */
 	if (regs->psw.mask & PSW_MASK_EA)
 		regs->psw.mask |= PSW_MASK_BA;
 	regs->psw.addr = user_sregs.regs.psw.addr;
 	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
 	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
 	       sizeof(current->thread.acrs));
 	restore_access_regs(current->thread.acrs);

 	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
 	       sizeof(current->thread.fp_regs));

 	restore_fp_regs(current->thread.fp_regs.fprs);
 	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
 	return 0;
 }

 SYSCALL_DEFINE0(sigreturn)
 {
 	struct pt_regs *regs = task_pt_regs(current);
 	sigframe __user *frame = (sigframe __user *)regs->gprs[15];
 	sigset_t set;

 	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
 		goto badframe;
 	set_current_blocked(&set);
 	if (restore_sigregs(regs, &frame->sregs))
 		goto badframe;
 	return regs->gprs[2];
 badframe:
 	force_sig(SIGSEGV, current);
 	return 0;
 }

 SYSCALL_DEFINE0(rt_sigreturn)
 {
 	struct pt_regs *regs = task_pt_regs(current);
 	rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
 	sigset_t set;

 	if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
 		goto badframe;
 	set_current_blocked(&set);
 	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
 		goto badframe;
 	if (restore_altstack(&frame->uc.uc_stack))
 		goto badframe;
 	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];

 	/* Overflow on alternate signal stack gives SIGSEGV. */
 	if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
 		return (void __user *) -1UL;

 	/* 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;
 	}

 	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 int 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 (frame == (void __user *) -1UL)
 		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;
 	/* Force default amode and default user address space control. */
 	regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
 		(PSW_USER_BITS & PSW_MASK_ASC) |
 		(regs->psw.mask & ~PSW_MASK_ASC);
 	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. */
 	if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
 	    sig == SIGTRAP || sig == SIGFPE) {
 		/* set extra registers only for synchronous signals */
 		regs->gprs[4] = regs->int_code & 127;
 		regs->gprs[5] = regs->int_parm_long;
 		regs->gprs[6] = task_thread_info(current)->last_break;
 	}

 	/* Place signal number on stack to allow backtrace from handler.  */
 	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
 		goto give_sigsegv;
 	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)
 {
 	int err = 0;
 	rt_sigframe __user *frame;

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

 	if (frame == (void __user *) -1UL)
 		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(NULL, &frame->uc.uc_link);
 	err |= __save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
 	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;
 		if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_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;
 	/* Force default amode and default user address space control. */
 	regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
 		(PSW_USER_BITS & PSW_MASK_ASC) |
 		(regs->psw.mask & ~PSW_MASK_ASC);
 	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;
 	regs->gprs[5] = task_thread_info(current)->last_break;
 	return 0;

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

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

 	/* 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)
 		return;
 	signal_delivered(sig, info, ka, regs,
 				 test_thread_flag(TIF_SINGLE_STEP));
 }

 /*
  * 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.
  */
 void do_signal(struct pt_regs *regs)
 {
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;
 	sigset_t *oldset = sigmask_to_save();

 	/*
 	 * Get signal to deliver. When running under ptrace, at this point
 	 * the debugger may change all our registers, including the system
 	 * call information.
 	 */
 	current_thread_info()->system_call =
 		test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

 	if (signr > 0) {
 		/* Whee!  Actually deliver the signal.  */
 		if (current_thread_info()->system_call) {
 			regs->int_code = current_thread_info()->system_call;
 			/* Check for system call restarting. */
 			switch (regs->gprs[2]) {
 			case -ERESTART_RESTARTBLOCK:
 			case -ERESTARTNOHAND:
 				regs->gprs[2] = -EINTR;
 				break;
 			case -ERESTARTSYS:
 				if (!(ka.sa.sa_flags & SA_RESTART)) {
 					regs->gprs[2] = -EINTR;
 					break;
 				}
 			/* fallthrough */
 			case -ERESTARTNOINTR:
 				regs->gprs[2] = regs->orig_gpr2;
 				regs->psw.addr =
 					__rewind_psw(regs->psw,
 						     regs->int_code >> 16);
 				break;
 			}
 		}
 		/* No longer in a system call */
 		clear_pt_regs_flag(regs, PIF_SYSCALL);

 		if (is_compat_task())
 			handle_signal32(signr, &ka, &info, oldset, regs);
 		else
 			handle_signal(signr, &ka, &info, oldset, regs);
 		return;
 	}

 	/* No handlers present - check for system call restart */
 	clear_pt_regs_flag(regs, PIF_SYSCALL);
 	if (current_thread_info()->system_call) {
 		regs->int_code = current_thread_info()->system_call;
 		switch (regs->gprs[2]) {
 		case -ERESTART_RESTARTBLOCK:
 			/* Restart with sys_restart_syscall */
 			regs->int_code = __NR_restart_syscall;
 		/* fallthrough */
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:
 			/* Restart system call with magic TIF bit. */
 			regs->gprs[2] = regs->orig_gpr2;
 			set_pt_regs_flag(regs, PIF_SYSCALL);
 			if (test_thread_flag(TIF_SINGLE_STEP))
 				clear_pt_regs_flag(regs, PIF_PER_TRAP);
 			break;
 		}
 	}

 	/*
 	 * If there's no signal to deliver, we just put the saved sigmask back.
 	 */
 	restore_saved_sigmask();
 }

 void do_notify_resume(struct pt_regs *regs)
 {
 	clear_thread_flag(TIF_NOTIFY_RESUME);
 	tracehook_notify_resume(regs);
 }
	/*
	* Copyright IBM Corp. 1999, 2006
	* 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/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/tty.h>
	#include <linux/personality.h>
	#include <linux/binfmts.h>
	#include <linux/tracehook.h>
	#include <linux/syscalls.h>
	#include <linux/compat.h>
	#include <asm/ucontext.h>
	#include <asm/uaccess.h>
	#include <asm/lowcore.h>
	#include <asm/switch_to.h>
	#include "entry.h"

	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;

	/* Returns non-zero on fault. */
	static int save_sigregs(struct pt_regs regs, _sigregs __user sregs)
	{
	_sigregs user_sregs;

	save_access_regs(current->thread.acrs);

	/* Copy a 'clean' PSW mask to the user to avoid leaking
	information about whether PER is currently on. */
	user_sregs.regs.psw.mask = PSW_USER_BITS \|
	(regs->psw.mask & (PSW_MASK_USER \| PSW_MASK_RI));
	user_sregs.regs.psw.addr = regs->psw.addr;
	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
	sizeof(user_sregs.regs.acrs));
	/*
	* We have to store the fp registers to current->thread.fp_regs
	* to merge them with the emulated registers.
	*/
	save_fp_ctl(&current->thread.fp_regs.fpc);
	save_fp_regs(current->thread.fp_regs.fprs);
	memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
	sizeof(user_sregs.fpregs));
	if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
	return -EFAULT;
	return 0;
	}

	static int restore_sigregs(struct pt_regs regs, _sigregs __user sregs)
	{
	_sigregs user_sregs;

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

	if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
	return -EFAULT;

	if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
	return -EINVAL;

	/* Loading the floating-point-control word can fail. Do that first. */
	if (restore_fp_ctl(&user_sregs.fpregs.fpc))
	return -EINVAL;

	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
	regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER \| PSW_MASK_RI)) \|
	(user_sregs.regs.psw.mask & (PSW_MASK_USER \| PSW_MASK_RI));
	/* Check for invalid user address space control. */
	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
	regs->psw.mask = PSW_ASC_PRIMARY \|
	(regs->psw.mask & ~PSW_MASK_ASC);
	/* Check for invalid amode */
	if (regs->psw.mask & PSW_MASK_EA)
	regs->psw.mask \|= PSW_MASK_BA;
	regs->psw.addr = user_sregs.regs.psw.addr;
	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	sizeof(current->thread.acrs));
	restore_access_regs(current->thread.acrs);

	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
	sizeof(current->thread.fp_regs));

	restore_fp_regs(current->thread.fp_regs.fprs);
	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
	return 0;
	}

	SYSCALL_DEFINE0(sigreturn)
	{
	struct pt_regs *regs = task_pt_regs(current);
	sigframe __user frame = (sigframe __user )regs->gprs[15];
	sigset_t set;

	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
	goto badframe;
	set_current_blocked(&set);
	if (restore_sigregs(regs, &frame->sregs))
	goto badframe;
	return regs->gprs[2];
	badframe:
	force_sig(SIGSEGV, current);
	return 0;
	}

	SYSCALL_DEFINE0(rt_sigreturn)
	{
	struct pt_regs *regs = task_pt_regs(current);
	rt_sigframe __user frame = (rt_sigframe __user )regs->gprs[15];
	sigset_t set;

	if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
	goto badframe;
	set_current_blocked(&set);
	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
	goto badframe;
	if (restore_altstack(&frame->uc.uc_stack))
	goto badframe;
	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];

	/* Overflow on alternate signal stack gives SIGSEGV. */
	if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
	return (void __user *) -1UL;

	/* 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;
	}

	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 int 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 (frame == (void __user *) -1UL)
	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;
	/* Force default amode and default user address space control. */
	regs->psw.mask = PSW_MASK_EA \| PSW_MASK_BA \|
	(PSW_USER_BITS & PSW_MASK_ASC) \|
	(regs->psw.mask & ~PSW_MASK_ASC);
	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. */
	if (sig == SIGSEGV \|\| sig == SIGBUS \|\| sig == SIGILL \|\|
	sig == SIGTRAP \|\| sig == SIGFPE) {
	/* set extra registers only for synchronous signals */
	regs->gprs[4] = regs->int_code & 127;
	regs->gprs[5] = regs->int_parm_long;
	regs->gprs[6] = task_thread_info(current)->last_break;
	}

	/* Place signal number on stack to allow backtrace from handler. */
	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
	goto give_sigsegv;
	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)
	{
	int err = 0;
	rt_sigframe __user *frame;

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

	if (frame == (void __user *) -1UL)
	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(NULL, &frame->uc.uc_link);
	err \|= __save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
	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;
	if (__put_user(S390_SYSCALL_OPCODE \| __NR_rt_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;
	/* Force default amode and default user address space control. */
	regs->psw.mask = PSW_MASK_EA \| PSW_MASK_BA \|
	(PSW_USER_BITS & PSW_MASK_ASC) \|
	(regs->psw.mask & ~PSW_MASK_ASC);
	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;
	regs->gprs[5] = task_thread_info(current)->last_break;
	return 0;

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

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

	/* 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)
	return;
	signal_delivered(sig, info, ka, regs,
	test_thread_flag(TIF_SINGLE_STEP));
	}

	/*
	* 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.
	*/
	void do_signal(struct pt_regs *regs)
	{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	sigset_t *oldset = sigmask_to_save();

	/*
	* Get signal to deliver. When running under ptrace, at this point
	* the debugger may change all our registers, including the system
	* call information.
	*/
	current_thread_info()->system_call =
	test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	if (signr > 0) {
	/* Whee! Actually deliver the signal. */
	if (current_thread_info()->system_call) {
	regs->int_code = current_thread_info()->system_call;
	/* Check for system call restarting. */
	switch (regs->gprs[2]) {
	case -ERESTART_RESTARTBLOCK:
	case -ERESTARTNOHAND:
	regs->gprs[2] = -EINTR;
	break;
	case -ERESTARTSYS:
	if (!(ka.sa.sa_flags & SA_RESTART)) {
	regs->gprs[2] = -EINTR;
	break;
	}
	/* fallthrough */
	case -ERESTARTNOINTR:
	regs->gprs[2] = regs->orig_gpr2;
	regs->psw.addr =
	__rewind_psw(regs->psw,
	regs->int_code >> 16);
	break;
	}
	}
	/* No longer in a system call */
	clear_pt_regs_flag(regs, PIF_SYSCALL);

	if (is_compat_task())
	handle_signal32(signr, &ka, &info, oldset, regs);
	else
	handle_signal(signr, &ka, &info, oldset, regs);
	return;
	}

	/* No handlers present - check for system call restart */
	clear_pt_regs_flag(regs, PIF_SYSCALL);
	if (current_thread_info()->system_call) {
	regs->int_code = current_thread_info()->system_call;
	switch (regs->gprs[2]) {
	case -ERESTART_RESTARTBLOCK:
	/* Restart with sys_restart_syscall */
	regs->int_code = __NR_restart_syscall;
	/* fallthrough */
	case -ERESTARTNOHAND:
	case -ERESTARTSYS:
	case -ERESTARTNOINTR:
	/* Restart system call with magic TIF bit. */
	regs->gprs[2] = regs->orig_gpr2;
	set_pt_regs_flag(regs, PIF_SYSCALL);
	if (test_thread_flag(TIF_SINGLE_STEP))
	clear_pt_regs_flag(regs, PIF_PER_TRAP);
	break;
	}
	}

	/*
	* If there's no signal to deliver, we just put the saved sigmask back.
	*/
	restore_saved_sigmask();
	}

	void do_notify_resume(struct pt_regs *regs)
	{
	clear_thread_flag(TIF_NOTIFY_RESUME);
	tracehook_notify_resume(regs);
	}