diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 1227236..5c7e981 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -134,6 +134,31 @@
 	bool
 	default y
 
+config S390_SWITCH_AMODE
+	bool "Switch kernel/user addressing modes"
+	help
+	  This option allows to switch the addressing modes of kernel and user
+	  space. The kernel parameter switch_amode=on will enable this feature,
+	  default is disabled. Enabling this (via kernel parameter) on machines
+	  earlier than IBM System z9-109 EC/BC will reduce system performance.
+
+	  Note that this option will also be selected by selecting the execute
+	  protection option below. Enabling the execute protection via the
+	  noexec kernel parameter will also switch the addressing modes,
+	  independent of the switch_amode kernel parameter.
+
+
+config S390_EXEC_PROTECT
+	bool "Data execute protection"
+	select S390_SWITCH_AMODE
+	help
+	  This option allows to enable a buffer overflow protection for user
+	  space programs and it also selects the addressing mode option above.
+	  The kernel parameter noexec=on will enable this feature and also
+	  switch the addressing modes, default is disabled. Enabling this (via
+	  kernel parameter) on machines earlier than IBM System z9-109 EC/BC
+	  will reduce system performance.
+
 comment "Code generation options"
 
 choice
diff --git a/arch/s390/defconfig b/arch/s390/defconfig
index 46bb385..12eb97f 100644
--- a/arch/s390/defconfig
+++ b/arch/s390/defconfig
@@ -108,6 +108,8 @@
 CONFIG_COMPAT=y
 CONFIG_SYSVIPC_COMPAT=y
 CONFIG_AUDIT_ARCH=y
+CONFIG_S390_SWITCH_AMODE=y
+CONFIG_S390_EXEC_PROTECT=y
 
 #
 # Code generation options
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index cf84d69..666bb6d 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -69,6 +69,12 @@
 
 #include "compat_linux.h"
 
+long psw_user32_bits	= (PSW_BASE32_BITS | PSW_MASK_DAT | PSW_ASC_HOME |
+			   PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
+			   PSW_MASK_PSTATE | PSW_DEFAULT_KEY);
+long psw32_user_bits	= (PSW32_BASE_BITS | PSW32_MASK_DAT | PSW32_ASC_HOME |
+			   PSW32_MASK_IO | PSW32_MASK_EXT | PSW32_MASK_MCHECK |
+			   PSW32_MASK_PSTATE);
  
 /* For this source file, we want overflow handling. */
 
diff --git a/arch/s390/kernel/compat_linux.h b/arch/s390/kernel/compat_linux.h
index 1a18e29..e89f8c0 100644
--- a/arch/s390/kernel/compat_linux.h
+++ b/arch/s390/kernel/compat_linux.h
@@ -115,37 +115,6 @@
         __u32	addr;
 } _psw_t32 __attribute__ ((aligned(8)));
 
-#define PSW32_MASK_PER		0x40000000UL
-#define PSW32_MASK_DAT		0x04000000UL
-#define PSW32_MASK_IO		0x02000000UL
-#define PSW32_MASK_EXT		0x01000000UL
-#define PSW32_MASK_KEY		0x00F00000UL
-#define PSW32_MASK_MCHECK	0x00040000UL
-#define PSW32_MASK_WAIT		0x00020000UL
-#define PSW32_MASK_PSTATE	0x00010000UL
-#define PSW32_MASK_ASC		0x0000C000UL
-#define PSW32_MASK_CC		0x00003000UL
-#define PSW32_MASK_PM		0x00000f00UL
-
-#define PSW32_ADDR_AMODE31	0x80000000UL
-#define PSW32_ADDR_INSN		0x7FFFFFFFUL
-
-#define PSW32_BASE_BITS		0x00080000UL
-
-#define PSW32_ASC_PRIMARY	0x00000000UL
-#define PSW32_ASC_ACCREG	0x00004000UL
-#define PSW32_ASC_SECONDARY	0x00008000UL
-#define PSW32_ASC_HOME		0x0000C000UL
-
-#define PSW32_USER_BITS	(PSW32_BASE_BITS | PSW32_MASK_DAT | PSW32_ASC_HOME | \
-			 PSW32_MASK_IO | PSW32_MASK_EXT | PSW32_MASK_MCHECK | \
-			 PSW32_MASK_PSTATE)
-
-#define PSW32_MASK_MERGE(CURRENT,NEW) \
-        (((CURRENT) & ~(PSW32_MASK_CC|PSW32_MASK_PM)) | \
-         ((NEW) & (PSW32_MASK_CC|PSW32_MASK_PM)))
-
-
 typedef struct
 {
 	_psw_t32	psw;
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index 8d17b2a..887a988 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -298,7 +298,7 @@
 	_s390_regs_common32 regs32;
 	int err, i;
 
-	regs32.psw.mask = PSW32_MASK_MERGE(PSW32_USER_BITS,
+	regs32.psw.mask = PSW32_MASK_MERGE(psw32_user_bits,
 					   (__u32)(regs->psw.mask >> 32));
 	regs32.psw.addr = PSW32_ADDR_AMODE31 | (__u32) regs->psw.addr;
 	for (i = 0; i < NUM_GPRS; i++)
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 9e9972e..2c91226 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1016,12 +1016,12 @@
 	__ctl_clear_bit(0,28);
 
 	/* Set new machine check handler */
-	S390_lowcore.mcck_new_psw.mask = PSW_KERNEL_BITS & ~PSW_MASK_MCHECK;
+	S390_lowcore.mcck_new_psw.mask = psw_kernel_bits & ~PSW_MASK_MCHECK;
 	S390_lowcore.mcck_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) &reset_mcck_handler;
 
 	/* Set new program check handler */
-	S390_lowcore.program_new_psw.mask = PSW_KERNEL_BITS & ~PSW_MASK_MCHECK;
+	S390_lowcore.program_new_psw.mask = psw_kernel_bits & ~PSW_MASK_MCHECK;
 	S390_lowcore.program_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) &reset_pgm_handler;
 
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 6603fbb..5acfac6 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -144,7 +144,7 @@
 
 	trace_hardirqs_on();
 	/* Wait for external, I/O or machine check interrupt. */
-	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_WAIT |
+	__load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
 			PSW_MASK_IO | PSW_MASK_EXT);
 }
 
@@ -190,7 +190,7 @@
 	struct pt_regs regs;
 
 	memset(&regs, 0, sizeof(regs));
-	regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
+	regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
 	regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
 	regs.gprs[9] = (unsigned long) fn;
 	regs.gprs[10] = (unsigned long) arg;
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 29fde70..2a8f087 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -230,9 +230,9 @@
 		 */
 		if (addr == (addr_t) &dummy->regs.psw.mask &&
 #ifdef CONFIG_COMPAT
-		    data != PSW_MASK_MERGE(PSW_USER32_BITS, data) &&
+		    data != PSW_MASK_MERGE(psw_user32_bits, data) &&
 #endif
-		    data != PSW_MASK_MERGE(PSW_USER_BITS, data))
+		    data != PSW_MASK_MERGE(psw_user_bits, data))
 			/* Invalid psw mask. */
 			return -EINVAL;
 #ifndef CONFIG_64BIT
@@ -393,7 +393,7 @@
 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
 			/* Fake a 31 bit psw mask. */
 			tmp = (__u32)(task_pt_regs(child)->psw.mask >> 32);
-			tmp = PSW32_MASK_MERGE(PSW32_USER_BITS, tmp);
+			tmp = PSW32_MASK_MERGE(psw32_user_bits, tmp);
 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 			/* Fake a 31 bit psw address. */
 			tmp = (__u32) task_pt_regs(child)->psw.addr |
@@ -468,11 +468,11 @@
 		 */
 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
 			/* Build a 64 bit psw mask from 31 bit mask. */
-			if (tmp != PSW32_MASK_MERGE(PSW32_USER_BITS, tmp))
+			if (tmp != PSW32_MASK_MERGE(psw32_user_bits, tmp))
 				/* Invalid psw mask. */
 				return -EINVAL;
 			task_pt_regs(child)->psw.mask =
-				PSW_MASK_MERGE(PSW_USER32_BITS, (__u64) tmp << 32);
+				PSW_MASK_MERGE(psw_user32_bits, (__u64) tmp << 32);
 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 			/* Build a 64 bit psw address from 31 bit address. */
 			task_pt_regs(child)->psw.addr =
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 25bf727..b1b9a93 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -50,6 +50,13 @@
 #include <asm/page.h>
 #include <asm/ptrace.h>
 #include <asm/sections.h>
+#include <asm/compat.h>
+
+long psw_kernel_bits	= (PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_PRIMARY |
+			   PSW_MASK_MCHECK | PSW_DEFAULT_KEY);
+long psw_user_bits	= (PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_HOME |
+			   PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
+			   PSW_MASK_PSTATE | PSW_DEFAULT_KEY);
 
 /*
  * User copy operations.
@@ -383,6 +390,84 @@
 }
 early_param("ipldelay", early_parse_ipldelay);
 
+#ifdef CONFIG_S390_SWITCH_AMODE
+unsigned int switch_amode = 0;
+EXPORT_SYMBOL_GPL(switch_amode);
+
+static inline void set_amode_and_uaccess(unsigned long user_amode,
+					 unsigned long user32_amode)
+{
+	psw_user_bits = PSW_BASE_BITS | PSW_MASK_DAT | user_amode |
+			PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
+			PSW_MASK_PSTATE | PSW_DEFAULT_KEY;
+#ifdef CONFIG_COMPAT
+	psw_user32_bits = PSW_BASE32_BITS | PSW_MASK_DAT | user_amode |
+			  PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
+			  PSW_MASK_PSTATE | PSW_DEFAULT_KEY;
+	psw32_user_bits = PSW32_BASE_BITS | PSW32_MASK_DAT | user32_amode |
+			  PSW32_MASK_IO | PSW32_MASK_EXT | PSW32_MASK_MCHECK |
+			  PSW32_MASK_PSTATE;
+#endif
+	psw_kernel_bits = PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_HOME |
+			  PSW_MASK_MCHECK | PSW_DEFAULT_KEY;
+
+	if (MACHINE_HAS_MVCOS) {
+		printk("mvcos available.\n");
+		memcpy(&uaccess, &uaccess_mvcos_switch, sizeof(uaccess));
+	} else {
+		printk("mvcos not available.\n");
+		memcpy(&uaccess, &uaccess_pt, sizeof(uaccess));
+	}
+}
+
+/*
+ * Switch kernel/user addressing modes?
+ */
+static int __init early_parse_switch_amode(char *p)
+{
+	switch_amode = 1;
+	return 0;
+}
+early_param("switch_amode", early_parse_switch_amode);
+
+#else /* CONFIG_S390_SWITCH_AMODE */
+static inline void set_amode_and_uaccess(unsigned long user_amode,
+					 unsigned long user32_amode)
+{
+}
+#endif /* CONFIG_S390_SWITCH_AMODE */
+
+#ifdef CONFIG_S390_EXEC_PROTECT
+unsigned int s390_noexec = 0;
+EXPORT_SYMBOL_GPL(s390_noexec);
+
+/*
+ * Enable execute protection?
+ */
+static int __init early_parse_noexec(char *p)
+{
+	if (!strncmp(p, "off", 3))
+		return 0;
+	switch_amode = 1;
+	s390_noexec = 1;
+	return 0;
+}
+early_param("noexec", early_parse_noexec);
+#endif /* CONFIG_S390_EXEC_PROTECT */
+
+static void setup_addressing_mode(void)
+{
+	if (s390_noexec) {
+		printk("S390 execute protection active, ");
+		set_amode_and_uaccess(PSW_ASC_SECONDARY, PSW32_ASC_SECONDARY);
+		return;
+	}
+	if (switch_amode) {
+		printk("S390 address spaces switched, ");
+		set_amode_and_uaccess(PSW_ASC_PRIMARY, PSW32_ASC_PRIMARY);
+	}
+}
+
 static void __init
 setup_lowcore(void)
 {
@@ -399,19 +484,21 @@
 	lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
 	lc->restart_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
-	lc->external_new_psw.mask = PSW_KERNEL_BITS;
+	if (switch_amode)
+		lc->restart_psw.mask |= PSW_ASC_HOME;
+	lc->external_new_psw.mask = psw_kernel_bits;
 	lc->external_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) ext_int_handler;
-	lc->svc_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
+	lc->svc_new_psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
 	lc->svc_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) system_call;
-	lc->program_new_psw.mask = PSW_KERNEL_BITS;
+	lc->program_new_psw.mask = psw_kernel_bits;
 	lc->program_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long)pgm_check_handler;
 	lc->mcck_new_psw.mask =
-		PSW_KERNEL_BITS & ~PSW_MASK_MCHECK & ~PSW_MASK_DAT;
+		psw_kernel_bits & ~PSW_MASK_MCHECK & ~PSW_MASK_DAT;
 	lc->mcck_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
-	lc->io_new_psw.mask = PSW_KERNEL_BITS;
+	lc->io_new_psw.mask = psw_kernel_bits;
 	lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler;
 	lc->ipl_device = S390_lowcore.ipl_device;
 	lc->jiffy_timer = -1LL;
@@ -645,6 +732,7 @@
 	parse_early_param();
 
 	setup_memory_end();
+	setup_addressing_mode();
 	setup_memory();
 	setup_resources();
 	setup_lowcore();
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 4c8a795..554f9cf 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -119,7 +119,7 @@
 
 	/* Copy a 'clean' PSW mask to the user to avoid leaking
 	   information about whether PER is currently on.  */
-	user_sregs.regs.psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
+	user_sregs.regs.psw.mask = PSW_MASK_MERGE(psw_user_bits, regs->psw.mask);
 	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,
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 3cb7e10..cb155d9 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -244,7 +244,7 @@
 void smp_send_stop(void)
 {
 	/* Disable all interrupts/machine checks */
-	__load_psw_mask(PSW_KERNEL_BITS & ~PSW_MASK_MCHECK);
+	__load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
 
         /* write magic number to zero page (absolute 0) */
 	lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;
diff --git a/arch/s390/lib/uaccess_mvcos.c b/arch/s390/lib/uaccess_mvcos.c
index 78c48f8..6d87723 100644
--- a/arch/s390/lib/uaccess_mvcos.c
+++ b/arch/s390/lib/uaccess_mvcos.c
@@ -162,6 +162,44 @@
 	return size;
 }
 
+static size_t strnlen_user_mvcos(size_t count, const char __user *src)
+{
+	char buf[256];
+	int rc;
+	size_t done, len, len_str;
+
+	done = 0;
+	do {
+		len = min(count - done, (size_t) 256);
+		rc = uaccess.copy_from_user(len, src + done, buf);
+		if (unlikely(rc == len))
+			return 0;
+		len -= rc;
+		len_str = strnlen(buf, len);
+		done += len_str;
+	} while ((len_str == len) && (done < count));
+	return done + 1;
+}
+
+static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
+				      char *dst)
+{
+	int rc;
+	size_t done, len, len_str;
+
+	done = 0;
+	do {
+		len = min(count - done, (size_t) 4096);
+		rc = uaccess.copy_from_user(len, src + done, dst);
+		if (unlikely(rc == len))
+			return -EFAULT;
+		len -= rc;
+		len_str = strnlen(dst, len);
+		done += len_str;
+	} while ((len_str == len) && (done < count));
+	return done;
+}
+
 struct uaccess_ops uaccess_mvcos = {
 	.copy_from_user = copy_from_user_mvcos_check,
 	.copy_from_user_small = copy_from_user_std,
@@ -174,3 +212,18 @@
 	.futex_atomic_op = futex_atomic_op_std,
 	.futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
 };
+
+#ifdef CONFIG_S390_SWITCH_AMODE
+struct uaccess_ops uaccess_mvcos_switch = {
+	.copy_from_user = copy_from_user_mvcos,
+	.copy_from_user_small = copy_from_user_mvcos,
+	.copy_to_user = copy_to_user_mvcos,
+	.copy_to_user_small = copy_to_user_mvcos,
+	.copy_in_user = copy_in_user_mvcos,
+	.clear_user = clear_user_mvcos,
+	.strnlen_user = strnlen_user_mvcos,
+	.strncpy_from_user = strncpy_from_user_mvcos,
+	.futex_atomic_op = futex_atomic_op_pt,
+	.futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
+};
+#endif
diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index 24ead55..637192f 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -1,7 +1,8 @@
 /*
  *  arch/s390/lib/uaccess_pt.c
  *
- *  User access functions based on page table walks.
+ *  User access functions based on page table walks for enhanced
+ *  system layout without hardware support.
  *
  *    Copyright IBM Corp. 2006
  *    Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
@@ -134,6 +135,49 @@
 	goto retry;
 }
 
+/*
+ * Do DAT for user address by page table walk, return kernel address.
+ * This function needs to be called with current->mm->page_table_lock held.
+ */
+static inline unsigned long __dat_user_addr(unsigned long uaddr)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long pfn, ret;
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+	int rc;
+
+	ret = 0;
+retry:
+	pgd = pgd_offset(mm, uaddr);
+	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+		goto fault;
+
+	pmd = pmd_offset(pgd, uaddr);
+	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+		goto fault;
+
+	pte = pte_offset_map(pmd, uaddr);
+	if (!pte || !pte_present(*pte))
+		goto fault;
+
+	pfn = pte_pfn(*pte);
+	if (!pfn_valid(pfn))
+		goto out;
+
+	ret = (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
+out:
+	return ret;
+fault:
+	spin_unlock(&mm->page_table_lock);
+	rc = __handle_fault(mm, uaddr, 0);
+	spin_lock(&mm->page_table_lock);
+	if (rc)
+		goto out;
+	goto retry;
+}
+
 size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
 {
 	size_t rc;
@@ -156,3 +200,277 @@
 	}
 	return __user_copy_pt((unsigned long) to, (void *) from, n, 1);
 }
+
+static size_t clear_user_pt(size_t n, void __user *to)
+{
+	long done, size, ret;
+
+	if (segment_eq(get_fs(), KERNEL_DS)) {
+		memset((void __kernel __force *) to, 0, n);
+		return 0;
+	}
+	done = 0;
+	do {
+		if (n - done > PAGE_SIZE)
+			size = PAGE_SIZE;
+		else
+			size = n - done;
+		ret = __user_copy_pt((unsigned long) to + done,
+				      &empty_zero_page, size, 1);
+		done += size;
+		if (ret)
+			return ret + n - done;
+	} while (done < n);
+	return 0;
+}
+
+static size_t strnlen_user_pt(size_t count, const char __user *src)
+{
+	char *addr;
+	unsigned long uaddr = (unsigned long) src;
+	struct mm_struct *mm = current->mm;
+	unsigned long offset, pfn, done, len;
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+	size_t len_str;
+
+	if (segment_eq(get_fs(), KERNEL_DS))
+		return strnlen((const char __kernel __force *) src, count) + 1;
+	done = 0;
+retry:
+	spin_lock(&mm->page_table_lock);
+	do {
+		pgd = pgd_offset(mm, uaddr);
+		if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+			goto fault;
+
+		pmd = pmd_offset(pgd, uaddr);
+		if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+			goto fault;
+
+		pte = pte_offset_map(pmd, uaddr);
+		if (!pte || !pte_present(*pte))
+			goto fault;
+
+		pfn = pte_pfn(*pte);
+		if (!pfn_valid(pfn)) {
+			done = -1;
+			goto out;
+		}
+
+		offset = uaddr & (PAGE_SIZE-1);
+		addr = (char *)(pfn << PAGE_SHIFT) + offset;
+		len = min(count - done, PAGE_SIZE - offset);
+		len_str = strnlen(addr, len);
+		done += len_str;
+		uaddr += len_str;
+	} while ((len_str == len) && (done < count));
+out:
+	spin_unlock(&mm->page_table_lock);
+	return done + 1;
+fault:
+	spin_unlock(&mm->page_table_lock);
+	if (__handle_fault(mm, uaddr, 0)) {
+		return 0;
+	}
+	goto retry;
+}
+
+static size_t strncpy_from_user_pt(size_t count, const char __user *src,
+				   char *dst)
+{
+	size_t n = strnlen_user_pt(count, src);
+
+	if (!n)
+		return -EFAULT;
+	if (n > count)
+		n = count;
+	if (segment_eq(get_fs(), KERNEL_DS)) {
+		memcpy(dst, (const char __kernel __force *) src, n);
+		if (dst[n-1] == '\0')
+			return n-1;
+		else
+			return n;
+	}
+	if (__user_copy_pt((unsigned long) src, dst, n, 0))
+		return -EFAULT;
+	if (dst[n-1] == '\0')
+		return n-1;
+	else
+		return n;
+}
+
+static size_t copy_in_user_pt(size_t n, void __user *to,
+			      const void __user *from)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to,
+		      uaddr, done, size;
+	unsigned long uaddr_from = (unsigned long) from;
+	unsigned long uaddr_to = (unsigned long) to;
+	pgd_t *pgd_from, *pgd_to;
+	pmd_t *pmd_from, *pmd_to;
+	pte_t *pte_from, *pte_to;
+	int write_user;
+
+	done = 0;
+retry:
+	spin_lock(&mm->page_table_lock);
+	do {
+		pgd_from = pgd_offset(mm, uaddr_from);
+		if (pgd_none(*pgd_from) || unlikely(pgd_bad(*pgd_from))) {
+			uaddr = uaddr_from;
+			write_user = 0;
+			goto fault;
+		}
+		pgd_to = pgd_offset(mm, uaddr_to);
+		if (pgd_none(*pgd_to) || unlikely(pgd_bad(*pgd_to))) {
+			uaddr = uaddr_to;
+			write_user = 1;
+			goto fault;
+		}
+
+		pmd_from = pmd_offset(pgd_from, uaddr_from);
+		if (pmd_none(*pmd_from) || unlikely(pmd_bad(*pmd_from))) {
+			uaddr = uaddr_from;
+			write_user = 0;
+			goto fault;
+		}
+		pmd_to = pmd_offset(pgd_to, uaddr_to);
+		if (pmd_none(*pmd_to) || unlikely(pmd_bad(*pmd_to))) {
+			uaddr = uaddr_to;
+			write_user = 1;
+			goto fault;
+		}
+
+		pte_from = pte_offset_map(pmd_from, uaddr_from);
+		if (!pte_from || !pte_present(*pte_from)) {
+			uaddr = uaddr_from;
+			write_user = 0;
+			goto fault;
+		}
+		pte_to = pte_offset_map(pmd_to, uaddr_to);
+		if (!pte_to || !pte_present(*pte_to) || !pte_write(*pte_to)) {
+			uaddr = uaddr_to;
+			write_user = 1;
+			goto fault;
+		}
+
+		pfn_from = pte_pfn(*pte_from);
+		if (!pfn_valid(pfn_from))
+			goto out;
+		pfn_to = pte_pfn(*pte_to);
+		if (!pfn_valid(pfn_to))
+			goto out;
+
+		offset_from = uaddr_from & (PAGE_SIZE-1);
+		offset_to = uaddr_from & (PAGE_SIZE-1);
+		offset_max = max(offset_from, offset_to);
+		size = min(n - done, PAGE_SIZE - offset_max);
+
+		memcpy((void *)(pfn_to << PAGE_SHIFT) + offset_to,
+		       (void *)(pfn_from << PAGE_SHIFT) + offset_from, size);
+		done += size;
+		uaddr_from += size;
+		uaddr_to += size;
+	} while (done < n);
+out:
+	spin_unlock(&mm->page_table_lock);
+	return n - done;
+fault:
+	spin_unlock(&mm->page_table_lock);
+	if (__handle_fault(mm, uaddr, write_user))
+		return n - done;
+	goto retry;
+}
+
+#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)	\
+	asm volatile("0: l   %1,0(%6)\n"				\
+		     "1: " insn						\
+		     "2: cs  %1,%2,0(%6)\n"				\
+		     "3: jl  1b\n"					\
+		     "   lhi %0,0\n"					\
+		     "4:\n"						\
+		     EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)	\
+		     : "=d" (ret), "=&d" (oldval), "=&d" (newval),	\
+		       "=m" (*uaddr)					\
+		     : "0" (-EFAULT), "d" (oparg), "a" (uaddr),		\
+		       "m" (*uaddr) : "cc" );
+
+int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
+{
+	int oldval = 0, newval, ret;
+
+	spin_lock(&current->mm->page_table_lock);
+	uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
+	if (!uaddr) {
+		spin_unlock(&current->mm->page_table_lock);
+		return -EFAULT;
+	}
+	get_page(virt_to_page(uaddr));
+	spin_unlock(&current->mm->page_table_lock);
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("lr %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("lr %2,%1\nar %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("lr %2,%1\nor %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("lr %2,%1\nnr %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("lr %2,%1\nxr %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+	put_page(virt_to_page(uaddr));
+	*old = oldval;
+	return ret;
+}
+
+int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
+{
+	int ret;
+
+	spin_lock(&current->mm->page_table_lock);
+	uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
+	if (!uaddr) {
+		spin_unlock(&current->mm->page_table_lock);
+		return -EFAULT;
+	}
+	get_page(virt_to_page(uaddr));
+	spin_unlock(&current->mm->page_table_lock);
+	asm volatile("   cs   %1,%4,0(%5)\n"
+		     "0: lr   %0,%1\n"
+		     "1:\n"
+		     EX_TABLE(0b,1b)
+		     : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
+		     : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
+		     : "cc", "memory" );
+	put_page(virt_to_page(uaddr));
+	return ret;
+}
+
+struct uaccess_ops uaccess_pt = {
+	.copy_from_user		= copy_from_user_pt,
+	.copy_from_user_small	= copy_from_user_pt,
+	.copy_to_user		= copy_to_user_pt,
+	.copy_to_user_small	= copy_to_user_pt,
+	.copy_in_user		= copy_in_user_pt,
+	.clear_user		= clear_user_pt,
+	.strnlen_user		= strnlen_user_pt,
+	.strncpy_from_user	= strncpy_from_user_pt,
+	.futex_atomic_op	= futex_atomic_op_pt,
+	.futex_atomic_cmpxchg	= futex_atomic_cmpxchg_pt,
+};
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 3382e29..9ff143e 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -137,7 +137,9 @@
 
 /*
  * Check which address space the address belongs to.
- * Returns 1 for user space and 0 for kernel space.
+ * May return 1 or 2 for user space and 0 for kernel space.
+ * Returns 2 for user space in primary addressing mode with
+ * CONFIG_S390_EXEC_PROTECT on and kernel parameter noexec=on.
  */
 static inline int check_user_space(struct pt_regs *regs, int error_code)
 {
@@ -154,7 +156,7 @@
 		return __check_access_register(regs, error_code);
 	if (descriptor == 2)
 		return current->thread.mm_segment.ar4;
-	return descriptor != 0;
+	return ((descriptor != 0) ^ (switch_amode)) << s390_noexec;
 }
 
 /*
@@ -183,6 +185,77 @@
 	force_sig_info(SIGSEGV, &si, current);
 }
 
+#ifdef CONFIG_S390_EXEC_PROTECT
+extern long sys_sigreturn(struct pt_regs *regs);
+extern long sys_rt_sigreturn(struct pt_regs *regs);
+extern long sys32_sigreturn(struct pt_regs *regs);
+extern long sys32_rt_sigreturn(struct pt_regs *regs);
+
+static inline void do_sigreturn(struct mm_struct *mm, struct pt_regs *regs,
+				int rt)
+{
+	up_read(&mm->mmap_sem);
+	clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
+#ifdef CONFIG_COMPAT
+	if (test_tsk_thread_flag(current, TIF_31BIT)) {
+		if (rt)
+			sys32_rt_sigreturn(regs);
+		else
+			sys32_sigreturn(regs);
+		return;
+	}
+#endif /* CONFIG_COMPAT */
+	if (rt)
+		sys_rt_sigreturn(regs);
+	else
+		sys_sigreturn(regs);
+	return;
+}
+
+static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
+			 unsigned long address, unsigned long error_code)
+{
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+	u16 *instruction;
+	unsigned long pfn, uaddr = regs->psw.addr;
+
+	spin_lock(&mm->page_table_lock);
+	pgd = pgd_offset(mm, uaddr);
+	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+		goto out_fault;
+	pmd = pmd_offset(pgd, uaddr);
+	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+		goto out_fault;
+	pte = pte_offset_map(pmd_offset(pgd_offset(mm, uaddr), uaddr), uaddr);
+	if (!pte || !pte_present(*pte))
+		goto out_fault;
+	pfn = pte_pfn(*pte);
+	if (!pfn_valid(pfn))
+		goto out_fault;
+	spin_unlock(&mm->page_table_lock);
+
+	instruction = (u16 *) ((pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE-1)));
+	if (*instruction == 0x0a77)
+		do_sigreturn(mm, regs, 0);
+	else if (*instruction == 0x0aad)
+		do_sigreturn(mm, regs, 1);
+	else {
+		printk("- XXX - do_exception: task = %s, primary, NO EXEC "
+		       "-> SIGSEGV\n", current->comm);
+		up_read(&mm->mmap_sem);
+		current->thread.prot_addr = address;
+		current->thread.trap_no = error_code;
+		do_sigsegv(regs, error_code, SEGV_MAPERR, address);
+	}
+	return 0;
+out_fault:
+	spin_unlock(&mm->page_table_lock);
+	return -EFAULT;
+}
+#endif /* CONFIG_S390_EXEC_PROTECT */
+
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
@@ -260,6 +333,17 @@
         vma = find_vma(mm, address);
         if (!vma)
                 goto bad_area;
+
+#ifdef CONFIG_S390_EXEC_PROTECT
+	if (unlikely((user_address == 2) && !(vma->vm_flags & VM_EXEC)))
+		if (!signal_return(mm, regs, address, error_code))
+			/*
+			 * signal_return() has done an up_read(&mm->mmap_sem)
+			 * if it returns 0.
+			 */
+			return;
+#endif
+
         if (vma->vm_start <= address) 
                 goto good_area;
         if (!(vma->vm_flags & VM_GROWSDOWN))
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 0e7e9ac..162a338 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -104,7 +104,7 @@
 		pmd = pmd_offset(pgd, address);
 		pte = pte_offset_kernel(pmd, address);
 		new_pte = mk_pte_phys(address, __pgprot(_PAGE_RO));
-		set_pte(pte, new_pte);
+		*pte = new_pte;
 	}
 }
 
@@ -124,11 +124,11 @@
 #ifdef CONFIG_64BIT
 	pgdir_k = (__pa(swapper_pg_dir) & PAGE_MASK) | _KERN_REGION_TABLE;
 	for (i = 0; i < PTRS_PER_PGD; i++)
-		pgd_clear(pg_dir + i);
+		pgd_clear_kernel(pg_dir + i);
 #else
 	pgdir_k = (__pa(swapper_pg_dir) & PAGE_MASK) | _KERNSEG_TABLE;
 	for (i = 0; i < PTRS_PER_PGD; i++)
-		pmd_clear((pmd_t *)(pg_dir + i));
+		pmd_clear_kernel((pmd_t *)(pg_dir + i));
 #endif
 	vmem_map_init();
 	setup_ro_region();
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index cd3d93e..92a5651 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -82,7 +82,7 @@
 	if (!pmd)
 		return NULL;
 	for (i = 0; i < PTRS_PER_PMD; i++)
-		pmd_clear(pmd + i);
+		pmd_clear_kernel(pmd + i);
 	return pmd;
 }
 
@@ -97,7 +97,7 @@
 		return NULL;
 	pte_val(empty_pte) = _PAGE_TYPE_EMPTY;
 	for (i = 0; i < PTRS_PER_PTE; i++)
-		set_pte(pte + i, empty_pte);
+		pte[i] = empty_pte;
 	return pte;
 }
 
@@ -119,7 +119,7 @@
 			pm_dir = vmem_pmd_alloc();
 			if (!pm_dir)
 				goto out;
-			pgd_populate(&init_mm, pg_dir, pm_dir);
+			pgd_populate_kernel(&init_mm, pg_dir, pm_dir);
 		}
 
 		pm_dir = pmd_offset(pg_dir, address);
@@ -132,7 +132,7 @@
 
 		pt_dir = pte_offset_kernel(pm_dir, address);
 		pte = pfn_pte(address >> PAGE_SHIFT, PAGE_KERNEL);
-		set_pte(pt_dir, pte);
+		*pt_dir = pte;
 	}
 	ret = 0;
 out:
@@ -161,7 +161,7 @@
 		if (pmd_none(*pm_dir))
 			continue;
 		pt_dir = pte_offset_kernel(pm_dir, address);
-		set_pte(pt_dir, pte);
+		*pt_dir = pte;
 	}
 	flush_tlb_kernel_range(start, start + size);
 }
@@ -191,7 +191,7 @@
 			pm_dir = vmem_pmd_alloc();
 			if (!pm_dir)
 				goto out;
-			pgd_populate(&init_mm, pg_dir, pm_dir);
+			pgd_populate_kernel(&init_mm, pg_dir, pm_dir);
 		}
 
 		pm_dir = pmd_offset(pg_dir, address);
@@ -210,7 +210,7 @@
 			if (!new_page)
 				goto out;
 			pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
-			set_pte(pt_dir, pte);
+			*pt_dir = pte;
 		}
 	}
 	ret = 0;
diff --git a/include/asm-s390/compat.h b/include/asm-s390/compat.h
index 356a0b1..296f4f1 100644
--- a/include/asm-s390/compat.h
+++ b/include/asm-s390/compat.h
@@ -6,6 +6,34 @@
 #include <linux/types.h>
 #include <linux/sched.h>
 
+#define PSW32_MASK_PER		0x40000000UL
+#define PSW32_MASK_DAT		0x04000000UL
+#define PSW32_MASK_IO		0x02000000UL
+#define PSW32_MASK_EXT		0x01000000UL
+#define PSW32_MASK_KEY		0x00F00000UL
+#define PSW32_MASK_MCHECK	0x00040000UL
+#define PSW32_MASK_WAIT		0x00020000UL
+#define PSW32_MASK_PSTATE	0x00010000UL
+#define PSW32_MASK_ASC		0x0000C000UL
+#define PSW32_MASK_CC		0x00003000UL
+#define PSW32_MASK_PM		0x00000f00UL
+
+#define PSW32_ADDR_AMODE31	0x80000000UL
+#define PSW32_ADDR_INSN		0x7FFFFFFFUL
+
+#define PSW32_BASE_BITS		0x00080000UL
+
+#define PSW32_ASC_PRIMARY	0x00000000UL
+#define PSW32_ASC_ACCREG	0x00004000UL
+#define PSW32_ASC_SECONDARY	0x00008000UL
+#define PSW32_ASC_HOME		0x0000C000UL
+
+#define PSW32_MASK_MERGE(CURRENT,NEW) \
+	(((CURRENT) & ~(PSW32_MASK_CC|PSW32_MASK_PM)) | \
+	 ((NEW) & (PSW32_MASK_CC|PSW32_MASK_PM)))
+
+extern long psw32_user_bits;
+
 #define COMPAT_USER_HZ	100
 
 typedef u32		compat_size_t;
diff --git a/include/asm-s390/lowcore.h b/include/asm-s390/lowcore.h
index 74f7389..4a31d0a 100644
--- a/include/asm-s390/lowcore.h
+++ b/include/asm-s390/lowcore.h
@@ -220,7 +220,8 @@
 	__u32        kernel_asce;              /* 0xc4c */
 	__u32        user_asce;                /* 0xc50 */
 	__u32        panic_stack;              /* 0xc54 */
-	__u8         pad10[0xc60-0xc58];       /* 0xc58 */
+	__u32	     user_exec_asce;	       /* 0xc58 */
+	__u8	     pad10[0xc60-0xc5c];       /* 0xc5c */
 	/* entry.S sensitive area start */
 	struct       cpuinfo_S390 cpu_data;    /* 0xc60 */
 	__u32        ipl_device;               /* 0xc7c */
@@ -310,7 +311,8 @@
 	__u64        kernel_asce;              /* 0xd58 */
 	__u64        user_asce;                /* 0xd60 */
 	__u64        panic_stack;              /* 0xd68 */
-	__u8         pad10[0xd80-0xd70];       /* 0xd70 */
+	__u64	     user_exec_asce;	       /* 0xd70 */
+	__u8	     pad10[0xd80-0xd78];       /* 0xd78 */
 	/* entry.S sensitive area start */
 	struct       cpuinfo_S390 cpu_data;    /* 0xd80 */
 	__u32        ipl_device;               /* 0xdb8 */
diff --git a/include/asm-s390/mmu_context.h b/include/asm-s390/mmu_context.h
index bcf24a8..1d21da2 100644
--- a/include/asm-s390/mmu_context.h
+++ b/include/asm-s390/mmu_context.h
@@ -9,6 +9,7 @@
 #ifndef __S390_MMU_CONTEXT_H
 #define __S390_MMU_CONTEXT_H
 
+#include <asm/pgalloc.h>
 /*
  * get a new mmu context.. S390 don't know about contexts.
  */
@@ -16,29 +17,44 @@
 
 #define destroy_context(mm)             do { } while (0)
 
+#ifndef __s390x__
+#define LCTL_OPCODE "lctl"
+#define PGTABLE_BITS (_SEGMENT_TABLE|USER_STD_MASK)
+#else
+#define LCTL_OPCODE "lctlg"
+#define PGTABLE_BITS (_REGION_TABLE|USER_STD_MASK)
+#endif
+
 static inline void enter_lazy_tlb(struct mm_struct *mm,
                                   struct task_struct *tsk)
 {
 }
 
 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
-                             struct task_struct *tsk)
+			     struct task_struct *tsk)
 {
-        if (prev != next) {
-#ifndef __s390x__
-	        S390_lowcore.user_asce = (__pa(next->pgd)&PAGE_MASK) |
-                      (_SEGMENT_TABLE|USER_STD_MASK);
-                /* Load home space page table origin. */
-                asm volatile("lctl  13,13,%0"
-			     : : "m" (S390_lowcore.user_asce) );
-#else /* __s390x__ */
-                S390_lowcore.user_asce = (__pa(next->pgd) & PAGE_MASK) |
-			(_REGION_TABLE|USER_STD_MASK);
-		/* Load home space page table origin. */
-		asm volatile("lctlg  13,13,%0"
-			     : : "m" (S390_lowcore.user_asce) );
-#endif /* __s390x__ */
-        }
+	pgd_t *shadow_pgd = get_shadow_pgd(next->pgd);
+
+	if (prev != next) {
+		S390_lowcore.user_asce = (__pa(next->pgd) & PAGE_MASK) |
+					 PGTABLE_BITS;
+		if (shadow_pgd) {
+			/* Load primary/secondary space page table origin. */
+			S390_lowcore.user_exec_asce =
+				(__pa(shadow_pgd) & PAGE_MASK) | PGTABLE_BITS;
+			asm volatile(LCTL_OPCODE" 1,1,%0\n"
+				     LCTL_OPCODE" 7,7,%1"
+				     : : "m" (S390_lowcore.user_exec_asce),
+					 "m" (S390_lowcore.user_asce) );
+		} else if (switch_amode) {
+			/* Load primary space page table origin. */
+			asm volatile(LCTL_OPCODE" 1,1,%0"
+				     : : "m" (S390_lowcore.user_asce) );
+		} else
+			/* Load home space page table origin. */
+			asm volatile(LCTL_OPCODE" 13,13,%0"
+				     : : "m" (S390_lowcore.user_asce) );
+	}
 	cpu_set(smp_processor_id(), next->cpu_vm_mask);
 }
 
@@ -51,4 +67,4 @@
 	set_fs(current->thread.mm_segment);
 }
 
-#endif
+#endif /* __S390_MMU_CONTEXT_H */
diff --git a/include/asm-s390/pgalloc.h b/include/asm-s390/pgalloc.h
index 0707a7e..56c8a6c 100644
--- a/include/asm-s390/pgalloc.h
+++ b/include/asm-s390/pgalloc.h
@@ -47,6 +47,17 @@
 
 	if (!pgd)
 		return NULL;
+	if (s390_noexec) {
+		pgd_t *shadow_pgd = (pgd_t *)
+			__get_free_pages(GFP_KERNEL, PGD_ALLOC_ORDER);
+		struct page *page = virt_to_page(pgd);
+
+		if (!shadow_pgd) {
+			free_pages((unsigned long) pgd, PGD_ALLOC_ORDER);
+			return NULL;
+		}
+		page->lru.next = (void *) shadow_pgd;
+	}
 	for (i = 0; i < PTRS_PER_PGD; i++)
 #ifndef __s390x__
 		pmd_clear(pmd_offset(pgd + i, i*PGDIR_SIZE));
@@ -58,6 +69,10 @@
 
 static inline void pgd_free(pgd_t *pgd)
 {
+	pgd_t *shadow_pgd = get_shadow_pgd(pgd);
+
+	if (shadow_pgd)
+		free_pages((unsigned long) shadow_pgd, PGD_ALLOC_ORDER);
 	free_pages((unsigned long) pgd, PGD_ALLOC_ORDER);
 }
 
@@ -71,6 +86,7 @@
 #define pmd_free(x)                     do { } while (0)
 #define __pmd_free_tlb(tlb,x)		do { } while (0)
 #define pgd_populate(mm, pmd, pte)      BUG()
+#define pgd_populate_kernel(mm, pmd, pte)	BUG()
 #else /* __s390x__ */
 static inline pmd_t * pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
 {
@@ -79,6 +95,17 @@
 
 	if (!pmd)
 		return NULL;
+	if (s390_noexec) {
+		pmd_t *shadow_pmd = (pmd_t *)
+			__get_free_pages(GFP_KERNEL, PMD_ALLOC_ORDER);
+		struct page *page = virt_to_page(pmd);
+
+		if (!shadow_pmd) {
+			free_pages((unsigned long) pmd, PMD_ALLOC_ORDER);
+			return NULL;
+		}
+		page->lru.next = (void *) shadow_pmd;
+	}
 	for (i=0; i < PTRS_PER_PMD; i++)
 		pmd_clear(pmd + i);
 	return pmd;
@@ -86,6 +113,10 @@
 
 static inline void pmd_free (pmd_t *pmd)
 {
+	pmd_t *shadow_pmd = get_shadow_pmd(pmd);
+
+	if (shadow_pmd)
+		free_pages((unsigned long) shadow_pmd, PMD_ALLOC_ORDER);
 	free_pages((unsigned long) pmd, PMD_ALLOC_ORDER);
 }
 
@@ -95,11 +126,22 @@
 		pmd_free(pmd);			\
 	 } while (0)
 
-static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
+static inline void
+pgd_populate_kernel(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
 {
 	pgd_val(*pgd) = _PGD_ENTRY | __pa(pmd);
 }
 
+static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
+{
+	pgd_t *shadow_pgd = get_shadow_pgd(pgd);
+	pmd_t *shadow_pmd = get_shadow_pmd(pmd);
+
+	if (shadow_pgd && shadow_pmd)
+		pgd_populate_kernel(mm, shadow_pgd, shadow_pmd);
+	pgd_populate_kernel(mm, pgd, pmd);
+}
+
 #endif /* __s390x__ */
 
 static inline void 
@@ -119,7 +161,13 @@
 static inline void
 pmd_populate(struct mm_struct *mm, pmd_t *pmd, struct page *page)
 {
-	pmd_populate_kernel(mm, pmd, (pte_t *)page_to_phys(page));
+	pte_t *pte = (pte_t *)page_to_phys(page);
+	pmd_t *shadow_pmd = get_shadow_pmd(pmd);
+	pte_t *shadow_pte = get_shadow_pte(pte);
+
+	pmd_populate_kernel(mm, pmd, pte);
+	if (shadow_pmd && shadow_pte)
+		pmd_populate_kernel(mm, shadow_pmd, shadow_pte);
 }
 
 /*
@@ -133,6 +181,17 @@
 
 	if (!pte)
 		return NULL;
+	if (s390_noexec) {
+		pte_t *shadow_pte = (pte_t *)
+			__get_free_page(GFP_KERNEL|__GFP_REPEAT);
+		struct page *page = virt_to_page(pte);
+
+		if (!shadow_pte) {
+			free_page((unsigned long) pte);
+			return NULL;
+		}
+		page->lru.next = (void *) shadow_pte;
+	}
 	for (i=0; i < PTRS_PER_PTE; i++) {
 		pte_clear(mm, vmaddr, pte + i);
 		vmaddr += PAGE_SIZE;
@@ -151,14 +210,30 @@
 
 static inline void pte_free_kernel(pte_t *pte)
 {
-        free_page((unsigned long) pte);
+	pte_t *shadow_pte = get_shadow_pte(pte);
+
+	if (shadow_pte)
+		free_page((unsigned long) shadow_pte);
+	free_page((unsigned long) pte);
 }
 
 static inline void pte_free(struct page *pte)
 {
-        __free_page(pte);
+	struct page *shadow_page = get_shadow_page(pte);
+
+	if (shadow_page)
+		__free_page(shadow_page);
+	__free_page(pte);
 }
 
-#define __pte_free_tlb(tlb,pte) tlb_remove_page(tlb,pte)
+#define __pte_free_tlb(tlb, pte)					\
+({									\
+	struct mmu_gather *__tlb = (tlb);				\
+	struct page *__pte = (pte);					\
+	struct page *shadow_page = get_shadow_page(__pte);		\
+	if (shadow_page)						\
+		tlb_remove_page(__tlb, shadow_page);			\
+	tlb_remove_page(__tlb, __pte);					\
+})
 
 #endif /* _S390_PGALLOC_H */
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 304ee77..13c1654 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -224,6 +224,8 @@
 #define _PAGE_TYPE_FILE		0x601	/* bit 0x002 is used for offset !! */
 #define _PAGE_TYPE_RO		0x200
 #define _PAGE_TYPE_RW		0x000
+#define _PAGE_TYPE_EX_RO	0x202
+#define _PAGE_TYPE_EX_RW	0x002
 
 /*
  * PTE type bits are rather complicated. handle_pte_fault uses pte_present,
@@ -244,11 +246,13 @@
  * _PAGE_TYPE_FILE	11?1   ->   11?1
  * _PAGE_TYPE_RO	0100   ->   1100
  * _PAGE_TYPE_RW	0000   ->   1000
+ * _PAGE_TYPE_EX_RO	0110   ->   1110
+ * _PAGE_TYPE_EX_RW	0010   ->   1010
  *
- * pte_none is true for bits combinations 1000, 1100
+ * pte_none is true for bits combinations 1000, 1010, 1100, 1110
  * pte_present is true for bits combinations 0000, 0010, 0100, 0110, 1001
  * pte_file is true for bits combinations 1101, 1111
- * swap pte is 1011 and 0001, 0011, 0101, 0111, 1010 and 1110 are invalid.
+ * swap pte is 1011 and 0001, 0011, 0101, 0111 are invalid.
  */
 
 #ifndef __s390x__
@@ -313,33 +317,100 @@
 #define PAGE_NONE	__pgprot(_PAGE_TYPE_NONE)
 #define PAGE_RO		__pgprot(_PAGE_TYPE_RO)
 #define PAGE_RW		__pgprot(_PAGE_TYPE_RW)
+#define PAGE_EX_RO	__pgprot(_PAGE_TYPE_EX_RO)
+#define PAGE_EX_RW	__pgprot(_PAGE_TYPE_EX_RW)
 
 #define PAGE_KERNEL	PAGE_RW
 #define PAGE_COPY	PAGE_RO
 
 /*
- * The S390 can't do page protection for execute, and considers that the
- * same are read. Also, write permissions imply read permissions. This is
- * the closest we can get..
+ * Dependent on the EXEC_PROTECT option s390 can do execute protection.
+ * Write permission always implies read permission. In theory with a
+ * primary/secondary page table execute only can be implemented but
+ * it would cost an additional bit in the pte to distinguish all the
+ * different pte types. To avoid that execute permission currently
+ * implies read permission as well.
  */
          /*xwr*/
 #define __P000	PAGE_NONE
 #define __P001	PAGE_RO
 #define __P010	PAGE_RO
 #define __P011	PAGE_RO
-#define __P100	PAGE_RO
-#define __P101	PAGE_RO
-#define __P110	PAGE_RO
-#define __P111	PAGE_RO
+#define __P100	PAGE_EX_RO
+#define __P101	PAGE_EX_RO
+#define __P110	PAGE_EX_RO
+#define __P111	PAGE_EX_RO
 
 #define __S000	PAGE_NONE
 #define __S001	PAGE_RO
 #define __S010	PAGE_RW
 #define __S011	PAGE_RW
-#define __S100	PAGE_RO
-#define __S101	PAGE_RO
-#define __S110	PAGE_RW
-#define __S111	PAGE_RW
+#define __S100	PAGE_EX_RO
+#define __S101	PAGE_EX_RO
+#define __S110	PAGE_EX_RW
+#define __S111	PAGE_EX_RW
+
+#ifndef __s390x__
+# define PMD_SHADOW_SHIFT	1
+# define PGD_SHADOW_SHIFT	1
+#else /* __s390x__ */
+# define PMD_SHADOW_SHIFT	2
+# define PGD_SHADOW_SHIFT	2
+#endif /* __s390x__ */
+
+static inline struct page *get_shadow_page(struct page *page)
+{
+	if (s390_noexec && !list_empty(&page->lru))
+		return virt_to_page(page->lru.next);
+	return NULL;
+}
+
+static inline pte_t *get_shadow_pte(pte_t *ptep)
+{
+	unsigned long pteptr = (unsigned long) (ptep);
+
+	if (s390_noexec) {
+		unsigned long offset = pteptr & (PAGE_SIZE - 1);
+		void *addr = (void *) (pteptr ^ offset);
+		struct page *page = virt_to_page(addr);
+		if (!list_empty(&page->lru))
+			return (pte_t *) ((unsigned long) page->lru.next |
+								offset);
+	}
+	return NULL;
+}
+
+static inline pmd_t *get_shadow_pmd(pmd_t *pmdp)
+{
+	unsigned long pmdptr = (unsigned long) (pmdp);
+
+	if (s390_noexec) {
+		unsigned long offset = pmdptr &
+				((PAGE_SIZE << PMD_SHADOW_SHIFT) - 1);
+		void *addr = (void *) (pmdptr ^ offset);
+		struct page *page = virt_to_page(addr);
+		if (!list_empty(&page->lru))
+			return (pmd_t *) ((unsigned long) page->lru.next |
+								offset);
+	}
+	return NULL;
+}
+
+static inline pgd_t *get_shadow_pgd(pgd_t *pgdp)
+{
+	unsigned long pgdptr = (unsigned long) (pgdp);
+
+	if (s390_noexec) {
+		unsigned long offset = pgdptr &
+				((PAGE_SIZE << PGD_SHADOW_SHIFT) - 1);
+		void *addr = (void *) (pgdptr ^ offset);
+		struct page *page = virt_to_page(addr);
+		if (!list_empty(&page->lru))
+			return (pgd_t *) ((unsigned long) page->lru.next |
+								offset);
+	}
+	return NULL;
+}
 
 /*
  * Certain architectures need to do special things when PTEs
@@ -348,7 +419,16 @@
  */
 static inline void set_pte(pte_t *pteptr, pte_t pteval)
 {
+	pte_t *shadow_pte = get_shadow_pte(pteptr);
+
 	*pteptr = pteval;
+	if (shadow_pte) {
+		if (!(pte_val(pteval) & _PAGE_INVALID) &&
+		    (pte_val(pteval) & _PAGE_SWX))
+			pte_val(*shadow_pte) = pte_val(pteval) | _PAGE_RO;
+		else
+			pte_val(*shadow_pte) = _PAGE_TYPE_EMPTY;
+	}
 }
 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
 
@@ -466,7 +546,7 @@
 
 static inline void pgd_clear(pgd_t * pgdp)      { }
 
-static inline void pmd_clear(pmd_t * pmdp)
+static inline void pmd_clear_kernel(pmd_t * pmdp)
 {
 	pmd_val(pmdp[0]) = _PAGE_TABLE_INV;
 	pmd_val(pmdp[1]) = _PAGE_TABLE_INV;
@@ -474,24 +554,55 @@
 	pmd_val(pmdp[3]) = _PAGE_TABLE_INV;
 }
 
+static inline void pmd_clear(pmd_t * pmdp)
+{
+	pmd_t *shadow_pmd = get_shadow_pmd(pmdp);
+
+	pmd_clear_kernel(pmdp);
+	if (shadow_pmd)
+		pmd_clear_kernel(shadow_pmd);
+}
+
 #else /* __s390x__ */
 
-static inline void pgd_clear(pgd_t * pgdp)
+static inline void pgd_clear_kernel(pgd_t * pgdp)
 {
 	pgd_val(*pgdp) = _PGD_ENTRY_INV | _PGD_ENTRY;
 }
 
-static inline void pmd_clear(pmd_t * pmdp)
+static inline void pgd_clear(pgd_t * pgdp)
+{
+	pgd_t *shadow_pgd = get_shadow_pgd(pgdp);
+
+	pgd_clear_kernel(pgdp);
+	if (shadow_pgd)
+		pgd_clear_kernel(shadow_pgd);
+}
+
+static inline void pmd_clear_kernel(pmd_t * pmdp)
 {
 	pmd_val(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
 	pmd_val1(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
 }
 
+static inline void pmd_clear(pmd_t * pmdp)
+{
+	pmd_t *shadow_pmd = get_shadow_pmd(pmdp);
+
+	pmd_clear_kernel(pmdp);
+	if (shadow_pmd)
+		pmd_clear_kernel(shadow_pmd);
+}
+
 #endif /* __s390x__ */
 
 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
+	pte_t *shadow_pte = get_shadow_pte(ptep);
+
 	pte_val(*ptep) = _PAGE_TYPE_EMPTY;
+	if (shadow_pte)
+		pte_val(*shadow_pte) = _PAGE_TYPE_EMPTY;
 }
 
 /*
@@ -609,8 +720,11 @@
 		 unsigned long address, pte_t *ptep)
 {
 	pte_t pte = *ptep;
+	pte_t *shadow_pte = get_shadow_pte(ptep);
 
 	__ptep_ipte(address, ptep);
+	if (shadow_pte)
+		__ptep_ipte(address, shadow_pte);
 	return pte;
 }
 
diff --git a/include/asm-s390/processor.h b/include/asm-s390/processor.h
index 7a7f50e..5af8535 100644
--- a/include/asm-s390/processor.h
+++ b/include/asm-s390/processor.h
@@ -145,7 +145,7 @@
 
 #define start_thread(regs, new_psw, new_stackp) do {            \
 	set_fs(USER_DS);					\
-        regs->psw.mask  = PSW_USER_BITS;                        \
+	regs->psw.mask	= psw_user_bits;			\
         regs->psw.addr  = new_psw | PSW_ADDR_AMODE;             \
         regs->gprs[15]  = new_stackp ;                          \
 } while (0)
@@ -154,14 +154,14 @@
 
 #define start_thread(regs, new_psw, new_stackp) do {            \
 	set_fs(USER_DS);					\
-        regs->psw.mask  = PSW_USER_BITS;                        \
+	regs->psw.mask	= psw_user_bits;			\
         regs->psw.addr  = new_psw;                              \
         regs->gprs[15]  = new_stackp;                           \
 } while (0)
 
 #define start_thread31(regs, new_psw, new_stackp) do {          \
 	set_fs(USER_DS);					\
-	regs->psw.mask  = PSW_USER32_BITS;			\
+	regs->psw.mask	= psw_user32_bits;			\
         regs->psw.addr  = new_psw;                              \
         regs->gprs[15]  = new_stackp;                           \
 } while (0)
diff --git a/include/asm-s390/ptrace.h b/include/asm-s390/ptrace.h
index 7b768c5..fa6ca87 100644
--- a/include/asm-s390/ptrace.h
+++ b/include/asm-s390/ptrace.h
@@ -266,17 +266,12 @@
 #define PSW_ASC_SECONDARY	0x0000800000000000UL
 #define PSW_ASC_HOME		0x0000C00000000000UL
 
-#define PSW_USER32_BITS (PSW_BASE32_BITS | PSW_MASK_DAT | PSW_ASC_HOME | \
-			 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK | \
-			 PSW_MASK_PSTATE | PSW_DEFAULT_KEY)
+extern long psw_user32_bits;
 
 #endif /* __s390x__ */
 
-#define PSW_KERNEL_BITS	(PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_PRIMARY | \
-			 PSW_MASK_MCHECK | PSW_DEFAULT_KEY)
-#define PSW_USER_BITS	(PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_HOME | \
-			 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK | \
-			 PSW_MASK_PSTATE | PSW_DEFAULT_KEY)
+extern long psw_kernel_bits;
+extern long psw_user_bits;
 
 /* This macro merges a NEW PSW mask specified by the user into
    the currently active PSW mask CURRENT, modifying only those
diff --git a/include/asm-s390/setup.h b/include/asm-s390/setup.h
index 5427697..6b68ddd 100644
--- a/include/asm-s390/setup.h
+++ b/include/asm-s390/setup.h
@@ -42,6 +42,18 @@
 
 extern struct mem_chunk memory_chunk[];
 
+#ifdef CONFIG_S390_SWITCH_AMODE
+extern unsigned int switch_amode;
+#else
+#define switch_amode	(0)
+#endif
+
+#ifdef CONFIG_S390_EXEC_PROTECT
+extern unsigned int s390_noexec;
+#else
+#define s390_noexec	(0)
+#endif
+
 /*
  * Machine features detected in head.S
  */
diff --git a/include/asm-s390/smp.h b/include/asm-s390/smp.h
index 2d9e153..b957e4c 100644
--- a/include/asm-s390/smp.h
+++ b/include/asm-s390/smp.h
@@ -110,7 +110,7 @@
 static inline void smp_send_stop(void)
 {
 	/* Disable all interrupts/machine checks */
-	__load_psw_mask(PSW_KERNEL_BITS & ~PSW_MASK_MCHECK);
+	__load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
 }
 
 #define smp_cpu_not_running(cpu)	1
diff --git a/include/asm-s390/system.h b/include/asm-s390/system.h
index bd0b05a..bbe137c 100644
--- a/include/asm-s390/system.h
+++ b/include/asm-s390/system.h
@@ -373,8 +373,8 @@
 	__load_psw_mask(mask | (__raw_local_irq_stosm(0x00) & ~(-1UL >> 8)));
 }
 
-#define local_mcck_enable()  __set_psw_mask(PSW_KERNEL_BITS)
-#define local_mcck_disable() __set_psw_mask(PSW_KERNEL_BITS & ~PSW_MASK_MCHECK)
+#define local_mcck_enable()  __set_psw_mask(psw_kernel_bits)
+#define local_mcck_disable() __set_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK)
 
 #ifdef CONFIG_SMP
 
diff --git a/include/asm-s390/tlbflush.h b/include/asm-s390/tlbflush.h
index fa4dc91..66793f5 100644
--- a/include/asm-s390/tlbflush.h
+++ b/include/asm-s390/tlbflush.h
@@ -3,6 +3,7 @@
 
 #include <linux/mm.h>
 #include <asm/processor.h>
+#include <asm/pgalloc.h>
 
 /*
  * TLB flushing:
@@ -102,6 +103,14 @@
 	if (unlikely(cpus_empty(mm->cpu_vm_mask)))
 		return;
 	if (MACHINE_HAS_IDTE) {
+		pgd_t *shadow_pgd = get_shadow_pgd(mm->pgd);
+
+		if (shadow_pgd) {
+			asm volatile(
+				"	.insn	rrf,0xb98e0000,0,%0,%1,0"
+				: : "a" (2048),
+				"a" (__pa(shadow_pgd) & PAGE_MASK) : "cc" );
+		}
 		asm volatile(
 			"	.insn	rrf,0xb98e0000,0,%0,%1,0"
 			: : "a" (2048), "a" (__pa(mm->pgd)&PAGE_MASK) : "cc");
diff --git a/include/asm-s390/uaccess.h b/include/asm-s390/uaccess.h
index 73ac4e8..0235970 100644
--- a/include/asm-s390/uaccess.h
+++ b/include/asm-s390/uaccess.h
@@ -90,6 +90,8 @@
 extern struct uaccess_ops uaccess;
 extern struct uaccess_ops uaccess_std;
 extern struct uaccess_ops uaccess_mvcos;
+extern struct uaccess_ops uaccess_mvcos_switch;
+extern struct uaccess_ops uaccess_pt;
 
 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
 {