linux-user/s390x/signal.c - qemu - Git at Google

 /*
  *  Emulation of Linux signals
  *
  *  Copyright (c) 2003 Fabrice Bellard
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 #include "qemu/osdep.h"
 #include "qemu.h"
 #include "user-internals.h"
 #include "signal-common.h"
 #include "linux-user/trace.h"

 #define __NUM_GPRS 16
 #define __NUM_FPRS 16
 #define __NUM_ACRS 16

 #define __SIGNAL_FRAMESIZE      160 /* FIXME: 31-bit mode -> 96 */

 #define _SIGCONTEXT_NSIG        64
 #define _SIGCONTEXT_NSIG_BPW    64 /* FIXME: 31-bit mode -> 32 */
 #define _SIGCONTEXT_NSIG_WORDS  (_SIGCONTEXT_NSIG / _SIGCONTEXT_NSIG_BPW)
 #define _SIGMASK_COPY_SIZE    (sizeof(unsigned long)*_SIGCONTEXT_NSIG_WORDS)
 #define S390_SYSCALL_OPCODE ((uint16_t)0x0a00)

 typedef struct {
     target_psw_t psw;
     abi_ulong gprs[__NUM_GPRS];
     abi_uint acrs[__NUM_ACRS];
 } target_s390_regs_common;

 typedef struct {
     uint32_t fpc;
     uint32_t pad;
     uint64_t fprs[__NUM_FPRS];
 } target_s390_fp_regs;

 typedef struct {
     target_s390_regs_common regs;
     target_s390_fp_regs     fpregs;
 } target_sigregs;

 typedef struct {
     uint64_t vxrs_low[16];
     uint64_t vxrs_high[16][2];
     uint8_t reserved[128];
 } target_sigregs_ext;

 typedef struct {
     abi_ulong oldmask[_SIGCONTEXT_NSIG_WORDS];
     abi_ulong sregs;
 } target_sigcontext;

 typedef struct {
     uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
     target_sigcontext sc;
     target_sigregs sregs;
     int signo;
     target_sigregs_ext sregs_ext;
 } sigframe;

 #define TARGET_UC_VXRS 2

 struct target_ucontext {
     abi_ulong tuc_flags;
     abi_ulong tuc_link;
     target_stack_t tuc_stack;
     target_sigregs tuc_mcontext;
     target_sigset_t tuc_sigmask;
     uint8_t reserved[128 - sizeof(target_sigset_t)];
     target_sigregs_ext tuc_mcontext_ext;
 };

 typedef struct {
     uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
     /*
      * This field is no longer initialized by the kernel, but it's still a part
      * of the ABI.
      */
     uint16_t svc_insn;
     struct target_siginfo info;
     struct target_ucontext uc;
 } rt_sigframe;

 static inline abi_ulong
 get_sigframe(struct target_sigaction *ka, CPUS390XState *env, size_t frame_size)
 {
     abi_ulong sp;

     /* Default to using normal stack */
     sp = get_sp_from_cpustate(env);

     /* This is the X/Open sanctioned signal stack switching.  */
     if (ka->sa_flags & TARGET_SA_ONSTACK) {
         sp = target_sigsp(sp, ka);
     }

     /* This is the legacy signal stack switching. */
     else if (/* FIXME !user_mode(regs) */ 0 &&
              !(ka->sa_flags & TARGET_SA_RESTORER) &&
              ka->sa_restorer) {
         sp = (abi_ulong) ka->sa_restorer;
     }

     return (sp - frame_size) & -8ul;
 }

 #define PSW_USER_BITS   (PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | \
                          PSW_MASK_MCHECK | PSW_MASK_PSTATE | PSW_ASC_PRIMARY)
 #define PSW_MASK_USER   (PSW_MASK_ASC | PSW_MASK_CC | PSW_MASK_PM | \
                          PSW_MASK_64 | PSW_MASK_32)

 static void save_sigregs(CPUS390XState *env, target_sigregs *sregs)
 {
     uint64_t psw_mask = s390_cpu_get_psw_mask(env);
     int i;

     /*
      * Copy a 'clean' PSW mask to the user to avoid leaking
      * information about whether PER is currently on.
      * TODO: qemu does not support PSW_MASK_RI; it will never be set.
      */
     psw_mask = PSW_USER_BITS | (psw_mask & PSW_MASK_USER);
     __put_user(psw_mask, &sregs->regs.psw.mask);
     __put_user(env->psw.addr, &sregs->regs.psw.addr);

     for (i = 0; i < 16; i++) {
         __put_user(env->regs[i], &sregs->regs.gprs[i]);
     }
     for (i = 0; i < 16; i++) {
         __put_user(env->aregs[i], &sregs->regs.acrs[i]);
     }

     /*
      * We have to store the fp registers to current->thread.fp_regs
      * to merge them with the emulated registers.
      */
     __put_user(env->fpc, &sregs->fpregs.fpc);
     for (i = 0; i < 16; i++) {
         __put_user(*get_freg(env, i), &sregs->fpregs.fprs[i]);
     }
 }

 static void save_sigregs_ext(CPUS390XState *env, target_sigregs_ext *ext)
 {
     int i;

     /*
      * if (MACHINE_HAS_VX) ...
      * That said, we always allocate the stack storage and the
      * space is always available in env.
      */
     for (i = 0; i < 16; ++i) {
         __put_user(env->vregs[i][1], &ext->vxrs_low[i]);
     }
     for (i = 0; i < 16; ++i) {
         __put_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
         __put_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
     }
 }

 void setup_frame(int sig, struct target_sigaction *ka,
                  target_sigset_t *set, CPUS390XState *env)
 {
     sigframe *frame;
     abi_ulong frame_addr;
     abi_ulong restorer;

     frame_addr = get_sigframe(ka, env, sizeof(*frame));
     trace_user_setup_frame(env, frame_addr);
     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
         force_sigsegv(sig);
         return;
     }

     /* Set up backchain. */
     __put_user(env->regs[15], (abi_ulong *) frame);

     /* Create struct sigcontext on the signal stack. */
     /* Make sure that we're initializing all of oldmask. */
     QEMU_BUILD_BUG_ON(ARRAY_SIZE(frame->sc.oldmask) != 1);
     __put_user(set->sig[0], &frame->sc.oldmask[0]);
     __put_user(frame_addr + offsetof(sigframe, sregs), &frame->sc.sregs);

     /* Create _sigregs on the signal stack */
     save_sigregs(env, &frame->sregs);

     /*
      * ??? The kernel uses regs->gprs[2] here, which is not yet the signo.
      * Moreover the comment talks about allowing backtrace, which is really
      * done by the r15 copy above.
      */
     __put_user(sig, &frame->signo);

     /* Create sigregs_ext on the signal stack. */
     save_sigregs_ext(env, &frame->sregs_ext);

     /*
      * Set up to return from userspace.
      * If provided, use a stub already in userspace.
      */
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         restorer = ka->sa_restorer;
     } else {
         restorer = default_sigreturn;
     }

     /* Set up registers for signal handler */
     env->regs[14] = restorer;
     env->regs[15] = frame_addr;
     /* Force default amode and default user address space control. */
     env->psw.mask = PSW_MASK_64 | PSW_MASK_32 | PSW_ASC_PRIMARY
                   | (env->psw.mask & ~PSW_MASK_ASC);
     env->psw.addr = ka->_sa_handler;

     env->regs[2] = sig;
     env->regs[3] = frame_addr + offsetof(typeof(*frame), sc);

     /*
      * We forgot to include these in the sigcontext.
      * To avoid breaking binary compatibility, they are passed as args.
      */
     env->regs[4] = 0; /* FIXME: regs->int_code & 127 */
     env->regs[5] = 0; /* FIXME: regs->int_parm_long */
     env->regs[6] = 0; /* FIXME: current->thread.last_break */

     unlock_user_struct(frame, frame_addr, 1);
 }

 void setup_rt_frame(int sig, struct target_sigaction *ka,
                     target_siginfo_t *info,
                     target_sigset_t *set, CPUS390XState *env)
 {
     rt_sigframe *frame;
     abi_ulong frame_addr;
     abi_ulong restorer;
     abi_ulong uc_flags;

     frame_addr = get_sigframe(ka, env, sizeof *frame);
     trace_user_setup_rt_frame(env, frame_addr);
     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
         force_sigsegv(sig);
         return;
     }

     /* Set up backchain. */
     __put_user(env->regs[15], (abi_ulong *) frame);

     /*
      * Set up to return from userspace.
      * If provided, use a stub already in userspace.
      */
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         restorer = ka->sa_restorer;
     } else {
         restorer = default_rt_sigreturn;
     }

     /* Create siginfo on the signal stack. */
     tswap_siginfo(&frame->info, info);

     /* Create ucontext on the signal stack. */
     uc_flags = 0;
     if (s390_has_feat(S390_FEAT_VECTOR)) {
         uc_flags |= TARGET_UC_VXRS;
     }
     __put_user(uc_flags, &frame->uc.tuc_flags);
     __put_user(0, &frame->uc.tuc_link);
     target_save_altstack(&frame->uc.tuc_stack, env);
     save_sigregs(env, &frame->uc.tuc_mcontext);
     save_sigregs_ext(env, &frame->uc.tuc_mcontext_ext);
     tswap_sigset(&frame->uc.tuc_sigmask, set);

     /* Set up registers for signal handler */
     env->regs[14] = restorer;
     env->regs[15] = frame_addr;
     /* Force default amode and default user address space control. */
     env->psw.mask = PSW_MASK_64 | PSW_MASK_32 | PSW_ASC_PRIMARY
                   | (env->psw.mask & ~PSW_MASK_ASC);
     env->psw.addr = ka->_sa_handler;

     env->regs[2] = sig;
     env->regs[3] = frame_addr + offsetof(typeof(*frame), info);
     env->regs[4] = frame_addr + offsetof(typeof(*frame), uc);
     env->regs[5] = 0; /* FIXME: current->thread.last_break */
 }

 static void restore_sigregs(CPUS390XState *env, target_sigregs *sc)
 {
     uint64_t prev_addr, prev_mask, mask, addr;
     int i;

     for (i = 0; i < 16; i++) {
         __get_user(env->regs[i], &sc->regs.gprs[i]);
     }

     prev_addr = env->psw.addr;
     __get_user(mask, &sc->regs.psw.mask);
     __get_user(addr, &sc->regs.psw.addr);
     trace_user_s390x_restore_sigregs(env, addr, prev_addr);

     /*
      * Use current psw.mask to preserve PER bit.
      * TODO:
      *  if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
      *          return -EINVAL;
      * Simply do not allow it to be set in mask.
      */
     prev_mask = s390_cpu_get_psw_mask(env);
     mask = (prev_mask & ~PSW_MASK_USER) | (mask & PSW_MASK_USER);
     /* Check for invalid user address space control. */
     if ((mask & PSW_MASK_ASC) == PSW_ASC_HOME) {
         mask = (mask & ~PSW_MASK_ASC) | PSW_ASC_PRIMARY;
     }
     /* Check for invalid amode. */
     if (mask & PSW_MASK_64) {
         mask |= PSW_MASK_32;
     }
     s390_cpu_set_psw(env, mask, addr);

     for (i = 0; i < 16; i++) {
         __get_user(env->aregs[i], &sc->regs.acrs[i]);
     }
     __get_user(env->fpc, &sc->fpregs.fpc);
     for (i = 0; i < 16; i++) {
         __get_user(*get_freg(env, i), &sc->fpregs.fprs[i]);
     }
 }

 static void restore_sigregs_ext(CPUS390XState *env, target_sigregs_ext *ext)
 {
     int i;

     /*
      * if (MACHINE_HAS_VX) ...
      * That said, we always allocate the stack storage and the
      * space is always available in env.
      */
     for (i = 0; i < 16; ++i) {
         __get_user(env->vregs[i][1], &ext->vxrs_low[i]);
     }
     for (i = 0; i < 16; ++i) {
         __get_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
         __get_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
     }
 }

 long do_sigreturn(CPUS390XState *env)
 {
     sigframe *frame;
     abi_ulong frame_addr = env->regs[15];
     target_sigset_t target_set;
     sigset_t set;

     trace_user_do_sigreturn(env, frame_addr);
     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
         force_sig(TARGET_SIGSEGV);
         return -QEMU_ESIGRETURN;
     }

     /* Make sure that we're initializing all of target_set. */
     QEMU_BUILD_BUG_ON(ARRAY_SIZE(target_set.sig) != 1);
     __get_user(target_set.sig[0], &frame->sc.oldmask[0]);

     target_to_host_sigset_internal(&set, &target_set);
     set_sigmask(&set); /* ~_BLOCKABLE? */

     restore_sigregs(env, &frame->sregs);
     restore_sigregs_ext(env, &frame->sregs_ext);

     unlock_user_struct(frame, frame_addr, 0);
     return -QEMU_ESIGRETURN;
 }

 long do_rt_sigreturn(CPUS390XState *env)
 {
     rt_sigframe *frame;
     abi_ulong frame_addr = env->regs[15];
     sigset_t set;

     trace_user_do_rt_sigreturn(env, frame_addr);
     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
         force_sig(TARGET_SIGSEGV);
         return -QEMU_ESIGRETURN;
     }
     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);

     set_sigmask(&set); /* ~_BLOCKABLE? */

     restore_sigregs(env, &frame->uc.tuc_mcontext);
     restore_sigregs_ext(env, &frame->uc.tuc_mcontext_ext);

     target_restore_altstack(&frame->uc.tuc_stack, env);

     unlock_user_struct(frame, frame_addr, 0);
     return -QEMU_ESIGRETURN;
 }

 void setup_sigtramp(abi_ulong sigtramp_page)
 {
     uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 + 2, 0);
     assert(tramp != NULL);

     default_sigreturn = sigtramp_page;
     __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn, &tramp[0]);

     default_rt_sigreturn = sigtramp_page + 2;
     __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, &tramp[1]);

     unlock_user(tramp, sigtramp_page, 2 + 2);
 }
	/*
	* Emulation of Linux signals
	*
	* Copyright (c) 2003 Fabrice Bellard
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	*/
	#include "qemu/osdep.h"
	#include "qemu.h"
	#include "user-internals.h"
	#include "signal-common.h"
	#include "linux-user/trace.h"

	#define __NUM_GPRS 16
	#define __NUM_FPRS 16
	#define __NUM_ACRS 16

	#define __SIGNAL_FRAMESIZE 160 /* FIXME: 31-bit mode -> 96 */

	#define _SIGCONTEXT_NSIG 64
	#define _SIGCONTEXT_NSIG_BPW 64 /* FIXME: 31-bit mode -> 32 */
	#define _SIGCONTEXT_NSIG_WORDS (_SIGCONTEXT_NSIG / _SIGCONTEXT_NSIG_BPW)
	#define _SIGMASK_COPY_SIZE (sizeof(unsigned long)*_SIGCONTEXT_NSIG_WORDS)
	#define S390_SYSCALL_OPCODE ((uint16_t)0x0a00)

	typedef struct {
	target_psw_t psw;
	abi_ulong gprs[__NUM_GPRS];
	abi_uint acrs[__NUM_ACRS];
	} target_s390_regs_common;

	typedef struct {
	uint32_t fpc;
	uint32_t pad;
	uint64_t fprs[__NUM_FPRS];
	} target_s390_fp_regs;

	typedef struct {
	target_s390_regs_common regs;
	target_s390_fp_regs fpregs;
	} target_sigregs;

	typedef struct {
	uint64_t vxrs_low[16];
	uint64_t vxrs_high[16][2];
	uint8_t reserved[128];
	} target_sigregs_ext;

	typedef struct {
	abi_ulong oldmask[_SIGCONTEXT_NSIG_WORDS];
	abi_ulong sregs;
	} target_sigcontext;

	typedef struct {
	uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
	target_sigcontext sc;
	target_sigregs sregs;
	int signo;
	target_sigregs_ext sregs_ext;
	} sigframe;

	#define TARGET_UC_VXRS 2

	struct target_ucontext {
	abi_ulong tuc_flags;
	abi_ulong tuc_link;
	target_stack_t tuc_stack;
	target_sigregs tuc_mcontext;
	target_sigset_t tuc_sigmask;
	uint8_t reserved[128 - sizeof(target_sigset_t)];
	target_sigregs_ext tuc_mcontext_ext;
	};

	typedef struct {
	uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
	/*
	* This field is no longer initialized by the kernel, but it's still a part
	* of the ABI.
	*/
	uint16_t svc_insn;
	struct target_siginfo info;
	struct target_ucontext uc;
	} rt_sigframe;

	static inline abi_ulong
	get_sigframe(struct target_sigaction ka, CPUS390XState env, size_t frame_size)
	{
	abi_ulong sp;

	/* Default to using normal stack */
	sp = get_sp_from_cpustate(env);

	/* This is the X/Open sanctioned signal stack switching. */
	if (ka->sa_flags & TARGET_SA_ONSTACK) {
	sp = target_sigsp(sp, ka);
	}

	/* This is the legacy signal stack switching. */
	else if (/* FIXME !user_mode(regs) */ 0 &&
	!(ka->sa_flags & TARGET_SA_RESTORER) &&
	ka->sa_restorer) {
	sp = (abi_ulong) ka->sa_restorer;
	}

	return (sp - frame_size) & -8ul;
	}

	#define PSW_USER_BITS (PSW_MASK_DAT \| PSW_MASK_IO \| PSW_MASK_EXT \| \
	PSW_MASK_MCHECK \| PSW_MASK_PSTATE \| PSW_ASC_PRIMARY)
	#define PSW_MASK_USER (PSW_MASK_ASC \| PSW_MASK_CC \| PSW_MASK_PM \| \
	PSW_MASK_64 \| PSW_MASK_32)

	static void save_sigregs(CPUS390XState env, target_sigregs sregs)
	{
	uint64_t psw_mask = s390_cpu_get_psw_mask(env);
	int i;

	/*
	* Copy a 'clean' PSW mask to the user to avoid leaking
	* information about whether PER is currently on.
	* TODO: qemu does not support PSW_MASK_RI; it will never be set.
	*/
	psw_mask = PSW_USER_BITS \| (psw_mask & PSW_MASK_USER);
	__put_user(psw_mask, &sregs->regs.psw.mask);
	__put_user(env->psw.addr, &sregs->regs.psw.addr);

	for (i = 0; i < 16; i++) {
	__put_user(env->regs[i], &sregs->regs.gprs[i]);
	}
	for (i = 0; i < 16; i++) {
	__put_user(env->aregs[i], &sregs->regs.acrs[i]);
	}

	/*
	* We have to store the fp registers to current->thread.fp_regs
	* to merge them with the emulated registers.
	*/
	__put_user(env->fpc, &sregs->fpregs.fpc);
	for (i = 0; i < 16; i++) {
	__put_user(*get_freg(env, i), &sregs->fpregs.fprs[i]);
	}
	}

	static void save_sigregs_ext(CPUS390XState env, target_sigregs_ext ext)
	{
	int i;

	/*
	* if (MACHINE_HAS_VX) ...
	* That said, we always allocate the stack storage and the
	* space is always available in env.
	*/
	for (i = 0; i < 16; ++i) {
	__put_user(env->vregs[i][1], &ext->vxrs_low[i]);
	}
	for (i = 0; i < 16; ++i) {
	__put_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
	__put_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
	}
	}

	void setup_frame(int sig, struct target_sigaction *ka,
	target_sigset_t set, CPUS390XState env)
	{
	sigframe *frame;
	abi_ulong frame_addr;
	abi_ulong restorer;

	frame_addr = get_sigframe(ka, env, sizeof(*frame));
	trace_user_setup_frame(env, frame_addr);
	if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
	force_sigsegv(sig);
	return;
	}

	/* Set up backchain. */
	__put_user(env->regs[15], (abi_ulong *) frame);

	/* Create struct sigcontext on the signal stack. */
	/* Make sure that we're initializing all of oldmask. */
	QEMU_BUILD_BUG_ON(ARRAY_SIZE(frame->sc.oldmask) != 1);
	__put_user(set->sig[0], &frame->sc.oldmask[0]);
	__put_user(frame_addr + offsetof(sigframe, sregs), &frame->sc.sregs);

	/* Create _sigregs on the signal stack */
	save_sigregs(env, &frame->sregs);

	/*
	* ??? The kernel uses regs->gprs[2] here, which is not yet the signo.
	* Moreover the comment talks about allowing backtrace, which is really
	* done by the r15 copy above.
	*/
	__put_user(sig, &frame->signo);

	/* Create sigregs_ext on the signal stack. */
	save_sigregs_ext(env, &frame->sregs_ext);

	/*
	* Set up to return from userspace.
	* If provided, use a stub already in userspace.
	*/
	if (ka->sa_flags & TARGET_SA_RESTORER) {
	restorer = ka->sa_restorer;
	} else {
	restorer = default_sigreturn;
	}

	/* Set up registers for signal handler */
	env->regs[14] = restorer;
	env->regs[15] = frame_addr;
	/* Force default amode and default user address space control. */
	env->psw.mask = PSW_MASK_64 \| PSW_MASK_32 \| PSW_ASC_PRIMARY
	\| (env->psw.mask & ~PSW_MASK_ASC);
	env->psw.addr = ka->_sa_handler;

	env->regs[2] = sig;
	env->regs[3] = frame_addr + offsetof(typeof(*frame), sc);

	/*
	* We forgot to include these in the sigcontext.
	* To avoid breaking binary compatibility, they are passed as args.
	*/
	env->regs[4] = 0; /* FIXME: regs->int_code & 127 */
	env->regs[5] = 0; /* FIXME: regs->int_parm_long */
	env->regs[6] = 0; /* FIXME: current->thread.last_break */

	unlock_user_struct(frame, frame_addr, 1);
	}

	void setup_rt_frame(int sig, struct target_sigaction *ka,
	target_siginfo_t *info,
	target_sigset_t set, CPUS390XState env)
	{
	rt_sigframe *frame;
	abi_ulong frame_addr;
	abi_ulong restorer;
	abi_ulong uc_flags;

	frame_addr = get_sigframe(ka, env, sizeof *frame);
	trace_user_setup_rt_frame(env, frame_addr);
	if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
	force_sigsegv(sig);
	return;
	}

	/* Set up backchain. */
	__put_user(env->regs[15], (abi_ulong *) frame);

	/*
	* Set up to return from userspace.
	* If provided, use a stub already in userspace.
	*/
	if (ka->sa_flags & TARGET_SA_RESTORER) {
	restorer = ka->sa_restorer;
	} else {
	restorer = default_rt_sigreturn;
	}

	/* Create siginfo on the signal stack. */
	tswap_siginfo(&frame->info, info);

	/* Create ucontext on the signal stack. */
	uc_flags = 0;
	if (s390_has_feat(S390_FEAT_VECTOR)) {
	uc_flags \|= TARGET_UC_VXRS;
	}
	__put_user(uc_flags, &frame->uc.tuc_flags);
	__put_user(0, &frame->uc.tuc_link);
	target_save_altstack(&frame->uc.tuc_stack, env);
	save_sigregs(env, &frame->uc.tuc_mcontext);
	save_sigregs_ext(env, &frame->uc.tuc_mcontext_ext);
	tswap_sigset(&frame->uc.tuc_sigmask, set);

	/* Set up registers for signal handler */
	env->regs[14] = restorer;
	env->regs[15] = frame_addr;
	/* Force default amode and default user address space control. */
	env->psw.mask = PSW_MASK_64 \| PSW_MASK_32 \| PSW_ASC_PRIMARY
	\| (env->psw.mask & ~PSW_MASK_ASC);
	env->psw.addr = ka->_sa_handler;

	env->regs[2] = sig;
	env->regs[3] = frame_addr + offsetof(typeof(*frame), info);
	env->regs[4] = frame_addr + offsetof(typeof(*frame), uc);
	env->regs[5] = 0; /* FIXME: current->thread.last_break */
	}

	static void restore_sigregs(CPUS390XState env, target_sigregs sc)
	{
	uint64_t prev_addr, prev_mask, mask, addr;
	int i;

	for (i = 0; i < 16; i++) {
	__get_user(env->regs[i], &sc->regs.gprs[i]);
	}

	prev_addr = env->psw.addr;
	__get_user(mask, &sc->regs.psw.mask);
	__get_user(addr, &sc->regs.psw.addr);
	trace_user_s390x_restore_sigregs(env, addr, prev_addr);

	/*
	* Use current psw.mask to preserve PER bit.
	* TODO:
	* if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
	* return -EINVAL;
	* Simply do not allow it to be set in mask.
	*/
	prev_mask = s390_cpu_get_psw_mask(env);
	mask = (prev_mask & ~PSW_MASK_USER) \| (mask & PSW_MASK_USER);
	/* Check for invalid user address space control. */
	if ((mask & PSW_MASK_ASC) == PSW_ASC_HOME) {
	mask = (mask & ~PSW_MASK_ASC) \| PSW_ASC_PRIMARY;
	}
	/* Check for invalid amode. */
	if (mask & PSW_MASK_64) {
	mask \|= PSW_MASK_32;
	}
	s390_cpu_set_psw(env, mask, addr);

	for (i = 0; i < 16; i++) {
	__get_user(env->aregs[i], &sc->regs.acrs[i]);
	}
	__get_user(env->fpc, &sc->fpregs.fpc);
	for (i = 0; i < 16; i++) {
	__get_user(*get_freg(env, i), &sc->fpregs.fprs[i]);
	}
	}

	static void restore_sigregs_ext(CPUS390XState env, target_sigregs_ext ext)
	{
	int i;

	/*
	* if (MACHINE_HAS_VX) ...
	* That said, we always allocate the stack storage and the
	* space is always available in env.
	*/
	for (i = 0; i < 16; ++i) {
	__get_user(env->vregs[i][1], &ext->vxrs_low[i]);
	}
	for (i = 0; i < 16; ++i) {
	__get_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
	__get_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
	}
	}

	long do_sigreturn(CPUS390XState *env)
	{
	sigframe *frame;
	abi_ulong frame_addr = env->regs[15];
	target_sigset_t target_set;
	sigset_t set;

	trace_user_do_sigreturn(env, frame_addr);
	if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
	force_sig(TARGET_SIGSEGV);
	return -QEMU_ESIGRETURN;
	}

	/* Make sure that we're initializing all of target_set. */
	QEMU_BUILD_BUG_ON(ARRAY_SIZE(target_set.sig) != 1);
	__get_user(target_set.sig[0], &frame->sc.oldmask[0]);

	target_to_host_sigset_internal(&set, &target_set);
	set_sigmask(&set); /* ~_BLOCKABLE? */

	restore_sigregs(env, &frame->sregs);
	restore_sigregs_ext(env, &frame->sregs_ext);

	unlock_user_struct(frame, frame_addr, 0);
	return -QEMU_ESIGRETURN;
	}

	long do_rt_sigreturn(CPUS390XState *env)
	{
	rt_sigframe *frame;
	abi_ulong frame_addr = env->regs[15];
	sigset_t set;

	trace_user_do_rt_sigreturn(env, frame_addr);
	if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
	force_sig(TARGET_SIGSEGV);
	return -QEMU_ESIGRETURN;
	}
	target_to_host_sigset(&set, &frame->uc.tuc_sigmask);

	set_sigmask(&set); /* ~_BLOCKABLE? */

	restore_sigregs(env, &frame->uc.tuc_mcontext);
	restore_sigregs_ext(env, &frame->uc.tuc_mcontext_ext);

	target_restore_altstack(&frame->uc.tuc_stack, env);

	unlock_user_struct(frame, frame_addr, 0);
	return -QEMU_ESIGRETURN;
	}

	void setup_sigtramp(abi_ulong sigtramp_page)
	{
	uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 + 2, 0);
	assert(tramp != NULL);

	default_sigreturn = sigtramp_page;
	__put_user(S390_SYSCALL_OPCODE \| TARGET_NR_sigreturn, &tramp[0]);

	default_rt_sigreturn = sigtramp_page + 2;
	__put_user(S390_SYSCALL_OPCODE \| TARGET_NR_rt_sigreturn, &tramp[1]);

	unlock_user(tramp, sigtramp_page, 2 + 2);
	}