diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index 234f1d8..2e0a15b 100644
--- a/arch/s390/include/asm/compat.h
+++ b/arch/s390/include/asm/compat.h
@@ -20,7 +20,7 @@
 #define PSW32_MASK_CC		0x00003000UL
 #define PSW32_MASK_PM		0x00000f00UL

-#define PSW32_MASK_USER		0x00003F00UL
+#define PSW32_MASK_USER		0x0000FF00UL

 #define PSW32_ADDR_AMODE	0x80000000UL
 #define PSW32_ADDR_INSN		0x7FFFFFFFUL
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index aeb77f0..d3750e7 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -240,7 +240,7 @@ typedef struct
 #define PSW_MASK_EA		0x00000000UL
 #define PSW_MASK_BA		0x00000000UL

-#define PSW_MASK_USER		0x00003F00UL
+#define PSW_MASK_USER		0x0000FF00UL

 #define PSW_ADDR_AMODE		0x80000000UL
 #define PSW_ADDR_INSN		0x7FFFFFFFUL
@@ -269,7 +269,7 @@ typedef struct
 #define PSW_MASK_EA		0x0000000100000000UL
 #define PSW_MASK_BA		0x0000000080000000UL

-#define PSW_MASK_USER		0x00003F0180000000UL
+#define PSW_MASK_USER		0x0000FF0180000000UL

 #define PSW_ADDR_AMODE		0x0000000000000000UL
 #define PSW_ADDR_INSN		0xFFFFFFFFFFFFFFFFUL
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index 3c0c198..3901276 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -311,6 +311,10 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
 	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 		(__u64)(regs32.psw.mask & PSW32_MASK_USER) << 32 |
 		(__u64)(regs32.psw.addr & PSW32_ADDR_AMODE);
+	/* Check for invalid user address space control. */
+	if ((regs->psw.mask & PSW_MASK_ASC) >= (psw_kernel_bits & PSW_MASK_ASC))
+		regs->psw.mask = (psw_user_bits & PSW_MASK_ASC) |
+			(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (__u64)(regs32.psw.addr & PSW32_ADDR_INSN);
 	for (i = 0; i < NUM_GPRS; i++)
 		regs->gprs[i] = (__u64) regs32.gprs[i];
@@ -483,7 +487,10 @@ static int setup_frame32(int sig, struct k_sigaction *ka,

 	/* Set up registers for signal handler */
 	regs->gprs[15] = (__force __u64) frame;
-	regs->psw.mask |= PSW_MASK_BA;		/* force amode 31 */
+	/* Force 31 bit amode and default user address space control. */
+	regs->psw.mask = PSW_MASK_BA |
+		(psw_user_bits & PSW_MASK_ASC) |
+		(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (__force __u64) ka->sa.sa_handler;

 	regs->gprs[2] = map_signal(sig);
@@ -551,7 +558,10 @@ static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,

 	/* Set up registers for signal handler */
 	regs->gprs[15] = (__force __u64) frame;
-	regs->psw.mask |= PSW_MASK_BA;		/* force amode 31 */
+	/* Force 31 bit amode and default user address space control. */
+	regs->psw.mask = PSW_MASK_BA |
+		(psw_user_bits & PSW_MASK_ASC) |
+		(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (__u64) ka->sa.sa_handler;

 	regs->gprs[2] = map_signal(sig);
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index ac565b4..ddddb80 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -138,6 +138,10 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 	/* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */
 	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 		(user_sregs.regs.psw.mask & PSW_MASK_USER);
+	/* Check for invalid user address space control. */
+	if ((regs->psw.mask & PSW_MASK_ASC) >= (psw_kernel_bits & PSW_MASK_ASC))
+		regs->psw.mask = (psw_user_bits & PSW_MASK_ASC) |
+			(regs->psw.mask & ~PSW_MASK_ASC);
 	/* Check for invalid amode */
 	if (regs->psw.mask & PSW_MASK_EA)
 		regs->psw.mask |= PSW_MASK_BA;
@@ -275,7 +279,10 @@ static int setup_frame(int sig, struct k_sigaction *ka,

 	/* Set up registers for signal handler */
 	regs->gprs[15] = (unsigned long) frame;
-	regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;	/* 64 bit amode */
+	/* 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);
@@ -348,7 +355,10 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,

 	/* Set up registers for signal handler */
 	regs->gprs[15] = (unsigned long) frame;
-	regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;	/* 64 bit amode */
+	/* 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);