diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c
index e5bc4f0358..fb7065f243 100644
--- a/linux-user/s390x/signal.c
+++ b/linux-user/s390x/signal.c
@@ -32,7 +32,6 @@
 #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 PSW_ADDR_AMODE            0x0000000000000000UL /* 0x80000000UL for 31-bit */
 #define S390_SYSCALL_OPCODE ((uint16_t)0x0a00)
 
 typedef struct {
@@ -106,23 +105,25 @@ get_sigframe(struct target_sigaction *ka, CPUS390XState *env, size_t frame_size)
 static void save_sigregs(CPUS390XState *env, target_sigregs *sregs)
 {
     int i;
-    //save_access_regs(current->thread.acrs); FIXME
 
-    /* Copy a 'clean' PSW mask to the user to avoid leaking
-       information about whether PER is currently on.  */
+    /*
+     * Copy a 'clean' PSW mask to the user to avoid leaking
+     * information about whether PER is currently on.
+     */
     __put_user(env->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.
      */
-    //save_fp_regs(&current->thread.fp_regs); FIXME
     for (i = 0; i < 16; i++) {
         __put_user(*get_freg(env, i), &sregs->fpregs.fprs[i]);
     }
@@ -137,120 +138,124 @@ void setup_frame(int sig, struct target_sigaction *ka,
     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)) {
-        goto give_sigsegv;
-    }
-
-    __put_user(set->sig[0], &frame->sc.oldmask[0]);
-
-    save_sigregs(env, &frame->sregs);
-
-    __put_user((abi_ulong)(unsigned long)&frame->sregs,
-               (abi_ulong *)&frame->sc.sregs);
-
-    /* Set up to return from userspace.  If provided, use a stub
-       already in userspace.  */
-    if (ka->sa_flags & TARGET_SA_RESTORER) {
-        env->regs[14] = (unsigned long)
-                ka->sa_restorer | PSW_ADDR_AMODE;
-    } else {
-        env->regs[14] = (frame_addr + offsetof(sigframe, retcode))
-                        | PSW_ADDR_AMODE;
-        __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn,
-                   (uint16_t *)(frame->retcode));
+        force_sigsegv(sig);
+        return;
     }
 
     /* Set up backchain. */
     __put_user(env->regs[15], (abi_ulong *) frame);
 
+    /* Create struct sigcontext on the signal stack. */
+    for (int i = 0; i < ARRAY_SIZE(frame->sc.oldmask); ++i) {
+        __put_user(set->sig[i], &frame->sc.oldmask[i]);
+    }
+
+    save_sigregs(env, &frame->sregs);
+    __put_user(frame_addr + offsetof(sigframe, sregs), &frame->sc.sregs);
+
+    /* Place signal number on stack to allow backtrace from handler.  */
+    __put_user(sig, &frame->signo);
+
+    /*
+     * Set up to return from userspace.
+     * If provided, use a stub already in userspace.
+     */
+    if (ka->sa_flags & TARGET_SA_RESTORER) {
+        env->regs[14] = ka->sa_restorer;
+    } else {
+        env->regs[14] = frame_addr + offsetof(sigframe, retcode);
+        __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn,
+                   (uint16_t *)(frame->retcode));
+    }
+
     /* Set up registers for signal handler */
     env->regs[15] = frame_addr;
-    env->psw.addr = (target_ulong) ka->_sa_handler | PSW_ADDR_AMODE;
+
+    /* 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; //map_signal(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: no clue... current->thread.trap_no;
-    env->regs[5] = 0; // FIXME: no clue... current->thread.prot_addr;
+    /*
+     * 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 */
 
-    /* Place signal number on stack to allow backtrace from handler.  */
-    __put_user(env->regs[2], &frame->signo);
     unlock_user_struct(frame, frame_addr, 1);
-    return;
-
-give_sigsegv:
-    force_sigsegv(sig);
 }
 
 void setup_rt_frame(int sig, struct target_sigaction *ka,
                     target_siginfo_t *info,
                     target_sigset_t *set, CPUS390XState *env)
 {
-    int i;
     rt_sigframe *frame;
     abi_ulong frame_addr;
 
     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)) {
-        goto give_sigsegv;
-    }
-
-    tswap_siginfo(&frame->info, info);
-
-    /* Create the ucontext.  */
-    __put_user(0, &frame->uc.tuc_flags);
-    __put_user((abi_ulong)0, (abi_ulong *)&frame->uc.tuc_link);
-    target_save_altstack(&frame->uc.tuc_stack, env);
-    save_sigregs(env, &frame->uc.tuc_mcontext);
-    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
-        __put_user((abi_ulong)set->sig[i],
-                   (abi_ulong *)&frame->uc.tuc_sigmask.sig[i]);
-    }
-
-    /* Set up to return from userspace.  If provided, use a stub
-       already in userspace.  */
-    if (ka->sa_flags & TARGET_SA_RESTORER) {
-        env->regs[14] = ka->sa_restorer | PSW_ADDR_AMODE;
-    } else {
-        env->regs[14] = (frame_addr + offsetof(typeof(*frame), retcode))
-                        | PSW_ADDR_AMODE;
-        __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn,
-                   (uint16_t *)(frame->retcode));
+        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) {
+        env->regs[14] = ka->sa_restorer;
+    } else {
+        env->regs[14] = frame_addr + offsetof(typeof(*frame), retcode);
+        __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn,
+                   (uint16_t *)(frame->retcode));
+    }
+
+    /* Create siginfo on the signal stack. */
+    tswap_siginfo(&frame->info, info);
+
+    /* Create the ucontext.  */
+    __put_user(0, &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);
+    tswap_sigset(&frame->uc.tuc_sigmask, set);
+
     /* Set up registers for signal handler */
     env->regs[15] = frame_addr;
-    env->psw.addr = (target_ulong) ka->_sa_handler | PSW_ADDR_AMODE;
 
-    env->regs[2] = sig; //map_signal(sig);
+    /* 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);
-    return;
-
-give_sigsegv:
-    force_sigsegv(sig);
+    env->regs[5] = 0; /* FIXME: current->thread.last_break */
 }
 
-static int
-restore_sigregs(CPUS390XState *env, target_sigregs *sc)
+static void restore_sigregs(CPUS390XState *env, target_sigregs *sc)
 {
-    int err = 0;
+    target_ulong prev_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(env->psw.mask, &sc->regs.psw.mask);
-    trace_user_s390x_restore_sigregs(env, (unsigned long long)sc->regs.psw.addr,
-                                     (unsigned long long)env->psw.addr);
     __get_user(env->psw.addr, &sc->regs.psw.addr);
-    /* FIXME: 31-bit -> | PSW_ADDR_AMODE */
+    trace_user_s390x_restore_sigregs(env, env->psw.addr, prev_addr);
 
     for (i = 0; i < 16; i++) {
         __get_user(env->aregs[i], &sc->regs.acrs[i]);
@@ -258,8 +263,6 @@ restore_sigregs(CPUS390XState *env, target_sigregs *sc)
     for (i = 0; i < 16; i++) {
         __get_user(*get_freg(env, i), &sc->fpregs.fprs[i]);
     }
-
-    return err;
 }
 
 long do_sigreturn(CPUS390XState *env)
@@ -271,23 +274,21 @@ long do_sigreturn(CPUS390XState *env)
 
     trace_user_do_sigreturn(env, frame_addr);
     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
-        goto badframe;
+        force_sig(TARGET_SIGSEGV);
+        return -TARGET_QEMU_ESIGRETURN;
     }
-    __get_user(target_set.sig[0], &frame->sc.oldmask[0]);
 
+    QEMU_BUILD_BUG_ON(sizeof(target_set) != sizeof(frame->sc.oldmask));
+    for (int i = 0; i < ARRAY_SIZE(frame->sc.oldmask); ++i) {
+        __get_user(target_set.sig[i], &frame->sc.oldmask[i]);
+    }
     target_to_host_sigset_internal(&set, &target_set);
     set_sigmask(&set); /* ~_BLOCKABLE? */
 
-    if (restore_sigregs(env, &frame->sregs)) {
-        goto badframe;
-    }
+    restore_sigregs(env, &frame->sregs);
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
-
-badframe:
-    force_sig(TARGET_SIGSEGV);
-    return -TARGET_QEMU_ESIGRETURN;
 }
 
 long do_rt_sigreturn(CPUS390XState *env)
@@ -298,23 +299,16 @@ long do_rt_sigreturn(CPUS390XState *env)
 
     trace_user_do_rt_sigreturn(env, frame_addr);
     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
-        goto badframe;
+        force_sig(TARGET_SIGSEGV);
+        return -TARGET_QEMU_ESIGRETURN;
     }
-    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
 
+    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
     set_sigmask(&set); /* ~_BLOCKABLE? */
 
-    if (restore_sigregs(env, &frame->uc.tuc_mcontext)) {
-        goto badframe;
-    }
-
     target_restore_altstack(&frame->uc.tuc_stack, env);
+    restore_sigregs(env, &frame->uc.tuc_mcontext);
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
-
-badframe:
-    unlock_user_struct(frame, frame_addr, 0);
-    force_sig(TARGET_SIGSEGV);
-    return -TARGET_QEMU_ESIGRETURN;
 }
