diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index a34a9d612fc0f2d4ecc9a4bfbcef2794fba7de41..18cd6b592650962010b7c72f32b0d401cf572a57 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/uapi/asm/ptrace.h b/arch/s390/include/uapi/asm/ptrace.h
index 705588a16d70da6322ca349074a1b30de92f658a..a5ca214b34fdb1271e4fad48d9c7c7fb8c5a9437 100644
--- a/arch/s390/include/uapi/asm/ptrace.h
+++ b/arch/s390/include/uapi/asm/ptrace.h
@@ -239,7 +239,7 @@ 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		0x00003F8180000000UL
+#define PSW_MASK_USER		0x0000FF8180000000UL
 
 #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 a1e8a8694bb70561a8c78c35558ff3a635e2203e..593fcc9253fc433650e54fbc8f8f829f5d961e98 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -309,6 +309,10 @@ 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];
@@ -481,7 +485,10 @@ 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);
@@ -549,7 +556,10 @@ 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 c13a2a37ef007b2634a508b7053b0c3cc12e30b2..d1259d875074179ff11b232258fcc36ef98b90c3 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -136,6 +136,10 @@ 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;
@@ -273,7 +277,10 @@ 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);
@@ -346,7 +353,10 @@ 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);