Initial import

8 files changed, 1468 insertions, 0 deletions

diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
new file mode 100644
index 000000000..0e8fefe5b
--- /dev/null
+++ b/arch/s390/lib/Makefile
@@ -0,0 +1,9 @@
+#
+# Makefile for s390-specific library files..
+#
+
+lib-y += delay.o string.o uaccess.o find.o
+obj-y += mem.o
+lib-$(CONFIG_SMP) += spinlock.o
+lib-$(CONFIG_KPROBES) += probes.o
+lib-$(CONFIG_UPROBES) += probes.o
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
new file mode 100644
index 000000000..16dc42d83
--- /dev/null
+++ b/arch/s390/lib/delay.c
@@ -0,0 +1,129 @@
+/*
+ *    Precise Delay Loops for S390
+ *
+ *    Copyright IBM Corp. 1999, 2008
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ *		 Heiko Carstens <heiko.carstens@de.ibm.com>,
+ */
+
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/timex.h>
+#include <linux/module.h>
+#include <linux/irqflags.h>
+#include <linux/interrupt.h>
+#include <asm/vtimer.h>
+#include <asm/div64.h>
+
+void __delay(unsigned long loops)
+{
+        /*
+         * To end the bloody studid and useless discussion about the
+         * BogoMips number I took the liberty to define the __delay
+         * function in a way that that resulting BogoMips number will
+         * yield the megahertz number of the cpu. The important function
+         * is udelay and that is done using the tod clock. -- martin.
+         */
+	asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
+}
+
+static void __udelay_disabled(unsigned long long usecs)
+{
+	unsigned long cr0, cr6, new;
+	u64 clock_saved, end;
+
+	end = get_tod_clock() + (usecs << 12);
+	clock_saved = local_tick_disable();
+	__ctl_store(cr0, 0, 0);
+	__ctl_store(cr6, 6, 6);
+	new = (cr0 &  0xffff00e0) | 0x00000800;
+	__ctl_load(new , 0, 0);
+	new = 0;
+	__ctl_load(new, 6, 6);
+	lockdep_off();
+	do {
+		set_clock_comparator(end);
+		enabled_wait();
+	} while (get_tod_clock_fast() < end);
+	lockdep_on();
+	__ctl_load(cr0, 0, 0);
+	__ctl_load(cr6, 6, 6);
+	local_tick_enable(clock_saved);
+}
+
+static void __udelay_enabled(unsigned long long usecs)
+{
+	u64 clock_saved, end;
+
+	end = get_tod_clock_fast() + (usecs << 12);
+	do {
+		clock_saved = 0;
+		if (end < S390_lowcore.clock_comparator) {
+			clock_saved = local_tick_disable();
+			set_clock_comparator(end);
+		}
+		enabled_wait();
+		if (clock_saved)
+			local_tick_enable(clock_saved);
+	} while (get_tod_clock_fast() < end);
+}
+
+/*
+ * Waits for 'usecs' microseconds using the TOD clock comparator.
+ */
+void __udelay(unsigned long long usecs)
+{
+	unsigned long flags;
+
+	preempt_disable();
+	local_irq_save(flags);
+	if (in_irq()) {
+		__udelay_disabled(usecs);
+		goto out;
+	}
+	if (in_softirq()) {
+		if (raw_irqs_disabled_flags(flags))
+			__udelay_disabled(usecs);
+		else
+			__udelay_enabled(usecs);
+		goto out;
+	}
+	if (raw_irqs_disabled_flags(flags)) {
+		local_bh_disable();
+		__udelay_disabled(usecs);
+		_local_bh_enable();
+		goto out;
+	}
+	__udelay_enabled(usecs);
+out:
+	local_irq_restore(flags);
+	preempt_enable();
+}
+EXPORT_SYMBOL(__udelay);
+
+/*
+ * Simple udelay variant. To be used on startup and reboot
+ * when the interrupt handler isn't working.
+ */
+void udelay_simple(unsigned long long usecs)
+{
+	u64 end;
+
+	end = get_tod_clock_fast() + (usecs << 12);
+	while (get_tod_clock_fast() < end)
+		cpu_relax();
+}
+
+void __ndelay(unsigned long long nsecs)
+{
+	u64 end;
+
+	nsecs <<= 9;
+	do_div(nsecs, 125);
+	end = get_tod_clock_fast() + nsecs;
+	if (nsecs & ~0xfffUL)
+		__udelay(nsecs >> 12);
+	while (get_tod_clock_fast() < end)
+		barrier();
+}
+EXPORT_SYMBOL(__ndelay);
diff --git a/arch/s390/lib/find.c b/arch/s390/lib/find.c
new file mode 100644
index 000000000..922003c1b
--- /dev/null
+++ b/arch/s390/lib/find.c
@@ -0,0 +1,77 @@
+/*
+ * MSB0 numbered special bitops handling.
+ *
+ * On s390x the bits are numbered:
+ *   |0..............63|64............127|128...........191|192...........255|
+ * and on s390:
+ *   |0.....31|32....63|64....95|96...127|128..159|160..191|192..223|224..255|
+ *
+ * The reason for this bit numbering is the fact that the hardware sets bits
+ * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap
+ * from the 'wrong end'.
+ */
+
+#include <linux/compiler.h>
+#include <linux/bitops.h>
+#include <linux/export.h>
+
+unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size)
+{
+	const unsigned long *p = addr;
+	unsigned long result = 0;
+	unsigned long tmp;
+
+	while (size & ~(BITS_PER_LONG - 1)) {
+		if ((tmp = *(p++)))
+			goto found;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = (*p) & (~0UL << (BITS_PER_LONG - size));
+	if (!tmp)		/* Are any bits set? */
+		return result + size;	/* Nope. */
+found:
+	return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
+}
+EXPORT_SYMBOL(find_first_bit_inv);
+
+unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size,
+				unsigned long offset)
+{
+	const unsigned long *p = addr + (offset / BITS_PER_LONG);
+	unsigned long result = offset & ~(BITS_PER_LONG - 1);
+	unsigned long tmp;
+
+	if (offset >= size)
+		return size;
+	size -= result;
+	offset %= BITS_PER_LONG;
+	if (offset) {
+		tmp = *(p++);
+		tmp &= (~0UL >> offset);
+		if (size < BITS_PER_LONG)
+			goto found_first;
+		if (tmp)
+			goto found_middle;
+		size -= BITS_PER_LONG;
+		result += BITS_PER_LONG;
+	}
+	while (size & ~(BITS_PER_LONG-1)) {
+		if ((tmp = *(p++)))
+			goto found_middle;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+found_first:
+	tmp &= (~0UL << (BITS_PER_LONG - size));
+	if (!tmp)		/* Are any bits set? */
+		return result + size;	/* Nope. */
+found_middle:
+	return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
+}
+EXPORT_SYMBOL(find_next_bit_inv);
diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S
new file mode 100644
index 000000000..c6d553e85
--- /dev/null
+++ b/arch/s390/lib/mem.S
@@ -0,0 +1,88 @@
+/*
+ * String handling functions.
+ *
+ * Copyright IBM Corp. 2012
+ */
+
+#include <linux/linkage.h>
+
+/*
+ * memset implementation
+ *
+ * This code corresponds to the C construct below. We do distinguish
+ * between clearing (c == 0) and setting a memory array (c != 0) simply
+ * because nearly all memset invocations in the kernel clear memory and
+ * the xc instruction is preferred in such cases.
+ *
+ * void *memset(void *s, int c, size_t n)
+ * {
+ *	if (likely(c == 0))
+ *		return __builtin_memset(s, 0, n);
+ *	return __builtin_memset(s, c, n);
+ * }
+ */
+ENTRY(memset)
+	ltgr	%r4,%r4
+	bzr	%r14
+	ltgr	%r3,%r3
+	jnz	.Lmemset_fill
+	aghi	%r4,-1
+	srlg	%r3,%r4,8
+	ltgr	%r3,%r3
+	lgr	%r1,%r2
+	jz	.Lmemset_clear_rest
+.Lmemset_clear_loop:
+	xc	0(256,%r1),0(%r1)
+	la	%r1,256(%r1)
+	brctg	%r3,.Lmemset_clear_loop
+.Lmemset_clear_rest:
+	larl	%r3,.Lmemset_xc
+	ex	%r4,0(%r3)
+	br	%r14
+.Lmemset_fill:
+	stc	%r3,0(%r2)
+	cghi	%r4,1
+	lgr	%r1,%r2
+	ber	%r14
+	aghi	%r4,-2
+	srlg	%r3,%r4,8
+	ltgr	%r3,%r3
+	jz	.Lmemset_fill_rest
+.Lmemset_fill_loop:
+	mvc	1(256,%r1),0(%r1)
+	la	%r1,256(%r1)
+	brctg	%r3,.Lmemset_fill_loop
+.Lmemset_fill_rest:
+	larl	%r3,.Lmemset_mvc
+	ex	%r4,0(%r3)
+	br	%r14
+.Lmemset_xc:
+	xc	0(1,%r1),0(%r1)
+.Lmemset_mvc:
+	mvc	1(1,%r1),0(%r1)
+
+/*
+ * memcpy implementation
+ *
+ * void *memcpy(void *dest, const void *src, size_t n)
+ */
+ENTRY(memcpy)
+	ltgr	%r4,%r4
+	bzr	%r14
+	aghi	%r4,-1
+	srlg	%r5,%r4,8
+	ltgr	%r5,%r5
+	lgr	%r1,%r2
+	jnz	.Lmemcpy_loop
+.Lmemcpy_rest:
+	larl	%r5,.Lmemcpy_mvc
+	ex	%r4,0(%r5)
+	br	%r14
+.Lmemcpy_loop:
+	mvc	0(256,%r1),0(%r3)
+	la	%r1,256(%r1)
+	la	%r3,256(%r3)
+	brctg	%r5,.Lmemcpy_loop
+	j	.Lmemcpy_rest
+.Lmemcpy_mvc:
+	mvc	0(1,%r1),0(%r3)
diff --git a/arch/s390/lib/probes.c b/arch/s390/lib/probes.c
new file mode 100644
index 000000000..ae90e1ae3
--- /dev/null
+++ b/arch/s390/lib/probes.c
@@ -0,0 +1,159 @@
+/*
+ *    Common helper functions for kprobes and uprobes
+ *
+ *    Copyright IBM Corp. 2014
+ */
+
+#include <asm/kprobes.h>
+#include <asm/dis.h>
+
+int probe_is_prohibited_opcode(u16 *insn)
+{
+	if (!is_known_insn((unsigned char *)insn))
+		return -EINVAL;
+	switch (insn[0] >> 8) {
+	case 0x0c:	/* bassm */
+	case 0x0b:	/* bsm	 */
+	case 0x83:	/* diag  */
+	case 0x44:	/* ex	 */
+	case 0xac:	/* stnsm */
+	case 0xad:	/* stosm */
+		return -EINVAL;
+	case 0xc6:
+		switch (insn[0] & 0x0f) {
+		case 0x00: /* exrl   */
+			return -EINVAL;
+		}
+	}
+	switch (insn[0]) {
+	case 0x0101:	/* pr	 */
+	case 0xb25a:	/* bsa	 */
+	case 0xb240:	/* bakr  */
+	case 0xb258:	/* bsg	 */
+	case 0xb218:	/* pc	 */
+	case 0xb228:	/* pt	 */
+	case 0xb98d:	/* epsw	 */
+	case 0xe560:	/* tbegin */
+	case 0xe561:	/* tbeginc */
+	case 0xb2f8:	/* tend	 */
+		return -EINVAL;
+	}
+	return 0;
+}
+
+int probe_get_fixup_type(u16 *insn)
+{
+	/* default fixup method */
+	int fixup = FIXUP_PSW_NORMAL;
+
+	switch (insn[0] >> 8) {
+	case 0x05:	/* balr	*/
+	case 0x0d:	/* basr */
+		fixup = FIXUP_RETURN_REGISTER;
+		/* if r2 = 0, no branch will be taken */
+		if ((insn[0] & 0x0f) == 0)
+			fixup |= FIXUP_BRANCH_NOT_TAKEN;
+		break;
+	case 0x06:	/* bctr	*/
+	case 0x07:	/* bcr	*/
+		fixup = FIXUP_BRANCH_NOT_TAKEN;
+		break;
+	case 0x45:	/* bal	*/
+	case 0x4d:	/* bas	*/
+		fixup = FIXUP_RETURN_REGISTER;
+		break;
+	case 0x47:	/* bc	*/
+	case 0x46:	/* bct	*/
+	case 0x86:	/* bxh	*/
+	case 0x87:	/* bxle	*/
+		fixup = FIXUP_BRANCH_NOT_TAKEN;
+		break;
+	case 0x82:	/* lpsw	*/
+		fixup = FIXUP_NOT_REQUIRED;
+		break;
+	case 0xb2:	/* lpswe */
+		if ((insn[0] & 0xff) == 0xb2)
+			fixup = FIXUP_NOT_REQUIRED;
+		break;
+	case 0xa7:	/* bras	*/
+		if ((insn[0] & 0x0f) == 0x05)
+			fixup |= FIXUP_RETURN_REGISTER;
+		break;
+	case 0xc0:
+		if ((insn[0] & 0x0f) == 0x05)	/* brasl */
+			fixup |= FIXUP_RETURN_REGISTER;
+		break;
+	case 0xeb:
+		switch (insn[2] & 0xff) {
+		case 0x44: /* bxhg  */
+		case 0x45: /* bxleg */
+			fixup = FIXUP_BRANCH_NOT_TAKEN;
+			break;
+		}
+		break;
+	case 0xe3:	/* bctg	*/
+		if ((insn[2] & 0xff) == 0x46)
+			fixup = FIXUP_BRANCH_NOT_TAKEN;
+		break;
+	case 0xec:
+		switch (insn[2] & 0xff) {
+		case 0xe5: /* clgrb */
+		case 0xe6: /* cgrb  */
+		case 0xf6: /* crb   */
+		case 0xf7: /* clrb  */
+		case 0xfc: /* cgib  */
+		case 0xfd: /* cglib */
+		case 0xfe: /* cib   */
+		case 0xff: /* clib  */
+			fixup = FIXUP_BRANCH_NOT_TAKEN;
+			break;
+		}
+		break;
+	}
+	return fixup;
+}
+
+int probe_is_insn_relative_long(u16 *insn)
+{
+	/* Check if we have a RIL-b or RIL-c format instruction which
+	 * we need to modify in order to avoid instruction emulation. */
+	switch (insn[0] >> 8) {
+	case 0xc0:
+		if ((insn[0] & 0x0f) == 0x00) /* larl */
+			return true;
+		break;
+	case 0xc4:
+		switch (insn[0] & 0x0f) {
+		case 0x02: /* llhrl  */
+		case 0x04: /* lghrl  */
+		case 0x05: /* lhrl   */
+		case 0x06: /* llghrl */
+		case 0x07: /* sthrl  */
+		case 0x08: /* lgrl   */
+		case 0x0b: /* stgrl  */
+		case 0x0c: /* lgfrl  */
+		case 0x0d: /* lrl    */
+		case 0x0e: /* llgfrl */
+		case 0x0f: /* strl   */
+			return true;
+		}
+		break;
+	case 0xc6:
+		switch (insn[0] & 0x0f) {
+		case 0x02: /* pfdrl  */
+		case 0x04: /* cghrl  */
+		case 0x05: /* chrl   */
+		case 0x06: /* clghrl */
+		case 0x07: /* clhrl  */
+		case 0x08: /* cgrl   */
+		case 0x0a: /* clgrl  */
+		case 0x0c: /* cgfrl  */
+		case 0x0d: /* crl    */
+		case 0x0e: /* clgfrl */
+		case 0x0f: /* clrl   */
+			return true;
+		}
+		break;
+	}
+	return false;
+}
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
new file mode 100644
index 000000000..d6c9991f7
--- /dev/null
+++ b/arch/s390/lib/spinlock.c
@@ -0,0 +1,272 @@
+/*
+ *    Out of line spinlock code.
+ *
+ *    Copyright IBM Corp. 2004, 2006
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <asm/io.h>
+
+int spin_retry = -1;
+
+static int __init spin_retry_init(void)
+{
+	if (spin_retry < 0)
+		spin_retry = MACHINE_HAS_CAD ? 10 : 1000;
+	return 0;
+}
+early_initcall(spin_retry_init);
+
+/**
+ * spin_retry= parameter
+ */
+static int __init spin_retry_setup(char *str)
+{
+	spin_retry = simple_strtoul(str, &str, 0);
+	return 1;
+}
+__setup("spin_retry=", spin_retry_setup);
+
+static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old)
+{
+	asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock));
+}
+
+void arch_spin_lock_wait(arch_spinlock_t *lp)
+{
+	unsigned int cpu = SPINLOCK_LOCKVAL;
+	unsigned int owner;
+	int count;
+
+	while (1) {
+		owner = ACCESS_ONCE(lp->lock);
+		/* Try to get the lock if it is free. */
+		if (!owner) {
+			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+				return;
+			continue;
+		}
+		/* Check if the lock owner is running. */
+		if (!smp_vcpu_scheduled(~owner)) {
+			smp_yield_cpu(~owner);
+			continue;
+		}
+		/* Loop for a while on the lock value. */
+		count = spin_retry;
+		do {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&lp->lock, owner);
+			owner = ACCESS_ONCE(lp->lock);
+		} while (owner && count-- > 0);
+		if (!owner)
+			continue;
+		/*
+		 * For multiple layers of hypervisors, e.g. z/VM + LPAR
+		 * yield the CPU if the lock is still unavailable.
+		 */
+		if (!MACHINE_IS_LPAR)
+			smp_yield_cpu(~owner);
+	}
+}
+EXPORT_SYMBOL(arch_spin_lock_wait);
+
+void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
+{
+	unsigned int cpu = SPINLOCK_LOCKVAL;
+	unsigned int owner;
+	int count;
+
+	local_irq_restore(flags);
+	while (1) {
+		owner = ACCESS_ONCE(lp->lock);
+		/* Try to get the lock if it is free. */
+		if (!owner) {
+			local_irq_disable();
+			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+				return;
+			local_irq_restore(flags);
+		}
+		/* Check if the lock owner is running. */
+		if (!smp_vcpu_scheduled(~owner)) {
+			smp_yield_cpu(~owner);
+			continue;
+		}
+		/* Loop for a while on the lock value. */
+		count = spin_retry;
+		do {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&lp->lock, owner);
+			owner = ACCESS_ONCE(lp->lock);
+		} while (owner && count-- > 0);
+		if (!owner)
+			continue;
+		/*
+		 * For multiple layers of hypervisors, e.g. z/VM + LPAR
+		 * yield the CPU if the lock is still unavailable.
+		 */
+		if (!MACHINE_IS_LPAR)
+			smp_yield_cpu(~owner);
+	}
+}
+EXPORT_SYMBOL(arch_spin_lock_wait_flags);
+
+int arch_spin_trylock_retry(arch_spinlock_t *lp)
+{
+	unsigned int cpu = SPINLOCK_LOCKVAL;
+	unsigned int owner;
+	int count;
+
+	for (count = spin_retry; count > 0; count--) {
+		owner = ACCESS_ONCE(lp->lock);
+		/* Try to get the lock if it is free. */
+		if (!owner) {
+			if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+				return 1;
+		} else if (MACHINE_HAS_CAD)
+			_raw_compare_and_delay(&lp->lock, owner);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(arch_spin_trylock_retry);
+
+void _raw_read_lock_wait(arch_rwlock_t *rw)
+{
+	unsigned int owner, old;
+	int count = spin_retry;
+
+#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
+	__RAW_LOCK(&rw->lock, -1, __RAW_OP_ADD);
+#endif
+	owner = 0;
+	while (1) {
+		if (count-- <= 0) {
+			if (owner && !smp_vcpu_scheduled(~owner))
+				smp_yield_cpu(~owner);
+			count = spin_retry;
+		}
+		old = ACCESS_ONCE(rw->lock);
+		owner = ACCESS_ONCE(rw->owner);
+		if ((int) old < 0) {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&rw->lock, old);
+			continue;
+		}
+		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
+			return;
+	}
+}
+EXPORT_SYMBOL(_raw_read_lock_wait);
+
+int _raw_read_trylock_retry(arch_rwlock_t *rw)
+{
+	unsigned int old;
+	int count = spin_retry;
+
+	while (count-- > 0) {
+		old = ACCESS_ONCE(rw->lock);
+		if ((int) old < 0) {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&rw->lock, old);
+			continue;
+		}
+		if (_raw_compare_and_swap(&rw->lock, old, old + 1))
+			return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(_raw_read_trylock_retry);
+
+#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
+
+void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev)
+{
+	unsigned int owner, old;
+	int count = spin_retry;
+
+	owner = 0;
+	while (1) {
+		if (count-- <= 0) {
+			if (owner && !smp_vcpu_scheduled(~owner))
+				smp_yield_cpu(~owner);
+			count = spin_retry;
+		}
+		old = ACCESS_ONCE(rw->lock);
+		owner = ACCESS_ONCE(rw->owner);
+		smp_rmb();
+		if ((int) old >= 0) {
+			prev = __RAW_LOCK(&rw->lock, 0x80000000, __RAW_OP_OR);
+			old = prev;
+		}
+		if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
+			break;
+		if (MACHINE_HAS_CAD)
+			_raw_compare_and_delay(&rw->lock, old);
+	}
+}
+EXPORT_SYMBOL(_raw_write_lock_wait);
+
+#else /* CONFIG_HAVE_MARCH_Z196_FEATURES */
+
+void _raw_write_lock_wait(arch_rwlock_t *rw)
+{
+	unsigned int owner, old, prev;
+	int count = spin_retry;
+
+	prev = 0x80000000;
+	owner = 0;
+	while (1) {
+		if (count-- <= 0) {
+			if (owner && !smp_vcpu_scheduled(~owner))
+				smp_yield_cpu(~owner);
+			count = spin_retry;
+		}
+		old = ACCESS_ONCE(rw->lock);
+		owner = ACCESS_ONCE(rw->owner);
+		if ((int) old >= 0 &&
+		    _raw_compare_and_swap(&rw->lock, old, old | 0x80000000))
+			prev = old;
+		else
+			smp_rmb();
+		if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
+			break;
+		if (MACHINE_HAS_CAD)
+			_raw_compare_and_delay(&rw->lock, old);
+	}
+}
+EXPORT_SYMBOL(_raw_write_lock_wait);
+
+#endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
+
+int _raw_write_trylock_retry(arch_rwlock_t *rw)
+{
+	unsigned int old;
+	int count = spin_retry;
+
+	while (count-- > 0) {
+		old = ACCESS_ONCE(rw->lock);
+		if (old) {
+			if (MACHINE_HAS_CAD)
+				_raw_compare_and_delay(&rw->lock, old);
+			continue;
+		}
+		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
+			return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(_raw_write_trylock_retry);
+
+void arch_lock_relax(unsigned int cpu)
+{
+	if (!cpu)
+		return;
+	if (MACHINE_IS_LPAR && smp_vcpu_scheduled(~cpu))
+		return;
+	smp_yield_cpu(~cpu);
+}
+EXPORT_SYMBOL(arch_lock_relax);
diff --git a/arch/s390/lib/string.c b/arch/s390/lib/string.c
new file mode 100644
index 000000000..b647d5ff0
--- /dev/null
+++ b/arch/s390/lib/string.c
@@ -0,0 +1,342 @@
+/*
+ *    Optimized string functions
+ *
+ *  S390 version
+ *    Copyright IBM Corp. 2004
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ */
+
+#define IN_ARCH_STRING_C 1
+
+#include <linux/types.h>
+#include <linux/module.h>
+
+/*
+ * Helper functions to find the end of a string
+ */
+static inline char *__strend(const char *s)
+{
+	register unsigned long r0 asm("0") = 0;
+
+	asm volatile ("0: srst  %0,%1\n"
+		      "   jo    0b"
+		      : "+d" (r0), "+a" (s) :  : "cc" );
+	return (char *) r0;
+}
+
+static inline char *__strnend(const char *s, size_t n)
+{
+	register unsigned long r0 asm("0") = 0;
+	const char *p = s + n;
+
+	asm volatile ("0: srst  %0,%1\n"
+		      "   jo    0b"
+		      : "+d" (p), "+a" (s) : "d" (r0) : "cc" );
+	return (char *) p;
+}
+
+/**
+ * strlen - Find the length of a string
+ * @s: The string to be sized
+ *
+ * returns the length of @s
+ */
+size_t strlen(const char *s)
+{
+	return __strend(s) - s;
+}
+EXPORT_SYMBOL(strlen);
+
+/**
+ * strnlen - Find the length of a length-limited string
+ * @s: The string to be sized
+ * @n: The maximum number of bytes to search
+ *
+ * returns the minimum of the length of @s and @n
+ */
+size_t strnlen(const char * s, size_t n)
+{
+	return __strnend(s, n) - s;
+}
+EXPORT_SYMBOL(strnlen);
+
+/**
+ * strcpy - Copy a %NUL terminated string
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ *
+ * returns a pointer to @dest
+ */
+char *strcpy(char *dest, const char *src)
+{
+	register int r0 asm("0") = 0;
+	char *ret = dest;
+
+	asm volatile ("0: mvst  %0,%1\n"
+		      "   jo    0b"
+		      : "+&a" (dest), "+&a" (src) : "d" (r0)
+		      : "cc", "memory" );
+	return ret;
+}
+EXPORT_SYMBOL(strcpy);
+
+/**
+ * strlcpy - Copy a %NUL terminated string into a sized buffer
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @size: size of destination buffer
+ *
+ * Compatible with *BSD: the result is always a valid
+ * NUL-terminated string that fits in the buffer (unless,
+ * of course, the buffer size is zero). It does not pad
+ * out the result like strncpy() does.
+ */
+size_t strlcpy(char *dest, const char *src, size_t size)
+{
+	size_t ret = __strend(src) - src;
+
+	if (size) {
+		size_t len = (ret >= size) ? size-1 : ret;
+		dest[len] = '\0';
+		memcpy(dest, src, len);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(strlcpy);
+
+/**
+ * strncpy - Copy a length-limited, %NUL-terminated string
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @n: The maximum number of bytes to copy
+ *
+ * The result is not %NUL-terminated if the source exceeds
+ * @n bytes.
+ */
+char *strncpy(char *dest, const char *src, size_t n)
+{
+	size_t len = __strnend(src, n) - src;
+	memset(dest + len, 0, n - len);
+	memcpy(dest, src, len);
+	return dest;
+}
+EXPORT_SYMBOL(strncpy);
+
+/**
+ * strcat - Append one %NUL-terminated string to another
+ * @dest: The string to be appended to
+ * @src: The string to append to it
+ *
+ * returns a pointer to @dest
+ */
+char *strcat(char *dest, const char *src)
+{
+	register int r0 asm("0") = 0;
+	unsigned long dummy;
+	char *ret = dest;
+
+	asm volatile ("0: srst  %0,%1\n"
+		      "   jo    0b\n"
+		      "1: mvst  %0,%2\n"
+		      "   jo    1b"
+		      : "=&a" (dummy), "+a" (dest), "+a" (src)
+		      : "d" (r0), "0" (0UL) : "cc", "memory" );
+	return ret;
+}
+EXPORT_SYMBOL(strcat);
+
+/**
+ * strlcat - Append a length-limited, %NUL-terminated string to another
+ * @dest: The string to be appended to
+ * @src: The string to append to it
+ * @n: The size of the destination buffer.
+ */
+size_t strlcat(char *dest, const char *src, size_t n)
+{
+	size_t dsize = __strend(dest) - dest;
+	size_t len = __strend(src) - src;
+	size_t res = dsize + len;
+
+	if (dsize < n) {
+		dest += dsize;
+		n -= dsize;
+		if (len >= n)
+			len = n - 1;
+		dest[len] = '\0';
+		memcpy(dest, src, len);
+	}
+	return res;
+}
+EXPORT_SYMBOL(strlcat);
+
+/**
+ * strncat - Append a length-limited, %NUL-terminated string to another
+ * @dest: The string to be appended to
+ * @src: The string to append to it
+ * @n: The maximum numbers of bytes to copy
+ *
+ * returns a pointer to @dest
+ *
+ * Note that in contrast to strncpy, strncat ensures the result is
+ * terminated.
+ */
+char *strncat(char *dest, const char *src, size_t n)
+{
+	size_t len = __strnend(src, n) - src;
+	char *p = __strend(dest);
+
+	p[len] = '\0';
+	memcpy(p, src, len);
+	return dest;
+}
+EXPORT_SYMBOL(strncat);
+
+/**
+ * strcmp - Compare two strings
+ * @cs: One string
+ * @ct: Another string
+ *
+ * returns   0 if @cs and @ct are equal,
+ *         < 0 if @cs is less than @ct
+ *         > 0 if @cs is greater than @ct
+ */
+int strcmp(const char *cs, const char *ct)
+{
+	register int r0 asm("0") = 0;
+	int ret = 0;
+
+	asm volatile ("0: clst %2,%3\n"
+		      "   jo   0b\n"
+		      "   je   1f\n"
+		      "   ic   %0,0(%2)\n"
+		      "   ic   %1,0(%3)\n"
+		      "   sr   %0,%1\n"
+		      "1:"
+		      : "+d" (ret), "+d" (r0), "+a" (cs), "+a" (ct)
+		      : : "cc" );
+	return ret;
+}
+EXPORT_SYMBOL(strcmp);
+
+/**
+ * strrchr - Find the last occurrence of a character in a string
+ * @s: The string to be searched
+ * @c: The character to search for
+ */
+char * strrchr(const char * s, int c)
+{
+       size_t len = __strend(s) - s;
+
+       if (len)
+	       do {
+		       if (s[len] == (char) c)
+			       return (char *) s + len;
+	       } while (--len > 0);
+       return NULL;
+}
+EXPORT_SYMBOL(strrchr);
+
+/**
+ * strstr - Find the first substring in a %NUL terminated string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ */
+char * strstr(const char * s1,const char * s2)
+{
+	int l1, l2;
+
+	l2 = __strend(s2) - s2;
+	if (!l2)
+		return (char *) s1;
+	l1 = __strend(s1) - s1;
+	while (l1-- >= l2) {
+		register unsigned long r2 asm("2") = (unsigned long) s1;
+		register unsigned long r3 asm("3") = (unsigned long) l2;
+		register unsigned long r4 asm("4") = (unsigned long) s2;
+		register unsigned long r5 asm("5") = (unsigned long) l2;
+		int cc;
+
+		asm volatile ("0: clcle %1,%3,0\n"
+			      "   jo    0b\n"
+			      "   ipm   %0\n"
+			      "   srl   %0,28"
+			      : "=&d" (cc), "+a" (r2), "+a" (r3),
+			        "+a" (r4), "+a" (r5) : : "cc" );
+		if (!cc)
+			return (char *) s1;
+		s1++;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(strstr);
+
+/**
+ * memchr - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the first occurrence of @c, or %NULL
+ * if @c is not found
+ */
+void *memchr(const void *s, int c, size_t n)
+{
+	register int r0 asm("0") = (char) c;
+	const void *ret = s + n;
+
+	asm volatile ("0: srst  %0,%1\n"
+		      "   jo    0b\n"
+		      "   jl	1f\n"
+		      "   la    %0,0\n"
+		      "1:"
+		      : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
+	return (void *) ret;
+}
+EXPORT_SYMBOL(memchr);
+
+/**
+ * memcmp - Compare two areas of memory
+ * @cs: One area of memory
+ * @ct: Another area of memory
+ * @count: The size of the area.
+ */
+int memcmp(const void *cs, const void *ct, size_t n)
+{
+	register unsigned long r2 asm("2") = (unsigned long) cs;
+	register unsigned long r3 asm("3") = (unsigned long) n;
+	register unsigned long r4 asm("4") = (unsigned long) ct;
+	register unsigned long r5 asm("5") = (unsigned long) n;
+	int ret;
+
+	asm volatile ("0: clcle %1,%3,0\n"
+		      "   jo    0b\n"
+		      "   ipm   %0\n"
+		      "   srl   %0,28"
+		      : "=&d" (ret), "+a" (r2), "+a" (r3), "+a" (r4), "+a" (r5)
+		      : : "cc" );
+	if (ret)
+		ret = *(char *) r2 - *(char *) r4;
+	return ret;
+}
+EXPORT_SYMBOL(memcmp);
+
+/**
+ * memscan - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the first occurrence of @c, or 1 byte past
+ * the area if @c is not found
+ */
+void *memscan(void *s, int c, size_t n)
+{
+	register int r0 asm("0") = (char) c;
+	const void *ret = s + n;
+
+	asm volatile ("0: srst  %0,%1\n"
+		      "   jo    0b\n"
+		      : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
+	return (void *) ret;
+}
+EXPORT_SYMBOL(memscan);
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
new file mode 100644
index 000000000..4614d415b
--- /dev/null
+++ b/arch/s390/lib/uaccess.c
@@ -0,0 +1,392 @@
+/*
+ *  Standard user space access functions based on mvcp/mvcs and doing
+ *  interesting things in the secondary space mode.
+ *
+ *    Copyright IBM Corp. 2006,2014
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ *		 Gerald Schaefer (gerald.schaefer@de.ibm.com)
+ */
+
+#include <linux/jump_label.h>
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <asm/mmu_context.h>
+#include <asm/facility.h>
+
+static struct static_key have_mvcos = STATIC_KEY_INIT_FALSE;
+
+static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
+						 unsigned long size)
+{
+	register unsigned long reg0 asm("0") = 0x81UL;
+	unsigned long tmp1, tmp2;
+
+	tmp1 = -4096UL;
+	asm volatile(
+		"0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
+		"9: jz    7f\n"
+		"1: algr  %0,%3\n"
+		"   slgr  %1,%3\n"
+		"   slgr  %2,%3\n"
+		"   j     0b\n"
+		"2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
+		"   nr    %4,%3\n"	/* %4 = (ptr + 4095) & -4096 */
+		"   slgr  %4,%1\n"
+		"   clgr  %0,%4\n"	/* copy crosses next page boundary? */
+		"   jnh   4f\n"
+		"3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
+		"10:slgr  %0,%4\n"
+		"   algr  %2,%4\n"
+		"4: lghi  %4,-1\n"
+		"   algr  %4,%0\n"	/* copy remaining size, subtract 1 */
+		"   bras  %3,6f\n"	/* memset loop */
+		"   xc    0(1,%2),0(%2)\n"
+		"5: xc    0(256,%2),0(%2)\n"
+		"   la    %2,256(%2)\n"
+		"6: aghi  %4,-256\n"
+		"   jnm   5b\n"
+		"   ex    %4,0(%3)\n"
+		"   j     8f\n"
+		"7:slgr  %0,%0\n"
+		"8:\n"
+		EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
+		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+		: "d" (reg0) : "cc", "memory");
+	return size;
+}
+
+static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
+						unsigned long size)
+{
+	unsigned long tmp1, tmp2;
+
+	load_kernel_asce();
+	tmp1 = -256UL;
+	asm volatile(
+		"   sacf  0\n"
+		"0: mvcp  0(%0,%2),0(%1),%3\n"
+		"10:jz    8f\n"
+		"1: algr  %0,%3\n"
+		"   la    %1,256(%1)\n"
+		"   la    %2,256(%2)\n"
+		"2: mvcp  0(%0,%2),0(%1),%3\n"
+		"11:jnz   1b\n"
+		"   j     8f\n"
+		"3: la    %4,255(%1)\n"	/* %4 = ptr + 255 */
+		"   lghi  %3,-4096\n"
+		"   nr    %4,%3\n"	/* %4 = (ptr + 255) & -4096 */
+		"   slgr  %4,%1\n"
+		"   clgr  %0,%4\n"	/* copy crosses next page boundary? */
+		"   jnh   5f\n"
+		"4: mvcp  0(%4,%2),0(%1),%3\n"
+		"12:slgr  %0,%4\n"
+		"   algr  %2,%4\n"
+		"5: lghi  %4,-1\n"
+		"   algr  %4,%0\n"	/* copy remaining size, subtract 1 */
+		"   bras  %3,7f\n"	/* memset loop */
+		"   xc    0(1,%2),0(%2)\n"
+		"6: xc    0(256,%2),0(%2)\n"
+		"   la    %2,256(%2)\n"
+		"7: aghi  %4,-256\n"
+		"   jnm   6b\n"
+		"   ex    %4,0(%3)\n"
+		"   j     9f\n"
+		"8:slgr  %0,%0\n"
+		"9: sacf  768\n"
+		EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
+		EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
+		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+		: : "cc", "memory");
+	return size;
+}
+
+unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+	if (static_key_false(&have_mvcos))
+		return copy_from_user_mvcos(to, from, n);
+	return copy_from_user_mvcp(to, from, n);
+}
+EXPORT_SYMBOL(__copy_from_user);
+
+static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
+					       unsigned long size)
+{
+	register unsigned long reg0 asm("0") = 0x810000UL;
+	unsigned long tmp1, tmp2;
+
+	tmp1 = -4096UL;
+	asm volatile(
+		"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
+		"6: jz    4f\n"
+		"1: algr  %0,%3\n"
+		"   slgr  %1,%3\n"
+		"   slgr  %2,%3\n"
+		"   j     0b\n"
+		"2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
+		"   nr    %4,%3\n"	/* %4 = (ptr + 4095) & -4096 */
+		"   slgr  %4,%1\n"
+		"   clgr  %0,%4\n"	/* copy crosses next page boundary? */
+		"   jnh   5f\n"
+		"3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
+		"7: slgr  %0,%4\n"
+		"   j     5f\n"
+		"4: slgr  %0,%0\n"
+		"5:\n"
+		EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
+		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+		: "d" (reg0) : "cc", "memory");
+	return size;
+}
+
+static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
+					      unsigned long size)
+{
+	unsigned long tmp1, tmp2;
+
+	load_kernel_asce();
+	tmp1 = -256UL;
+	asm volatile(
+		"   sacf  0\n"
+		"0: mvcs  0(%0,%1),0(%2),%3\n"
+		"7: jz    5f\n"
+		"1: algr  %0,%3\n"
+		"   la    %1,256(%1)\n"
+		"   la    %2,256(%2)\n"
+		"2: mvcs  0(%0,%1),0(%2),%3\n"
+		"8: jnz   1b\n"
+		"   j     5f\n"
+		"3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
+		"   lghi  %3,-4096\n"
+		"   nr    %4,%3\n"	/* %4 = (ptr + 255) & -4096 */
+		"   slgr  %4,%1\n"
+		"   clgr  %0,%4\n"	/* copy crosses next page boundary? */
+		"   jnh   6f\n"
+		"4: mvcs  0(%4,%1),0(%2),%3\n"
+		"9: slgr  %0,%4\n"
+		"   j     6f\n"
+		"5: slgr  %0,%0\n"
+		"6: sacf  768\n"
+		EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
+		EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
+		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+		: : "cc", "memory");
+	return size;
+}
+
+unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+	if (static_key_false(&have_mvcos))
+		return copy_to_user_mvcos(to, from, n);
+	return copy_to_user_mvcs(to, from, n);
+}
+EXPORT_SYMBOL(__copy_to_user);
+
+static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
+					       unsigned long size)
+{
+	register unsigned long reg0 asm("0") = 0x810081UL;
+	unsigned long tmp1, tmp2;
+
+	tmp1 = -4096UL;
+	/* FIXME: copy with reduced length. */
+	asm volatile(
+		"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
+		"   jz	  2f\n"
+		"1: algr  %0,%3\n"
+		"   slgr  %1,%3\n"
+		"   slgr  %2,%3\n"
+		"   j	  0b\n"
+		"2:slgr  %0,%0\n"
+		"3: \n"
+		EX_TABLE(0b,3b)
+		: "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
+		: "d" (reg0) : "cc", "memory");
+	return size;
+}
+
+static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
+					     unsigned long size)
+{
+	unsigned long tmp1;
+
+	load_kernel_asce();
+	asm volatile(
+		"   sacf  256\n"
+		"   aghi  %0,-1\n"
+		"   jo	  5f\n"
+		"   bras  %3,3f\n"
+		"0: aghi  %0,257\n"
+		"1: mvc	  0(1,%1),0(%2)\n"
+		"   la	  %1,1(%1)\n"
+		"   la	  %2,1(%2)\n"
+		"   aghi  %0,-1\n"
+		"   jnz	  1b\n"
+		"   j	  5f\n"
+		"2: mvc	  0(256,%1),0(%2)\n"
+		"   la	  %1,256(%1)\n"
+		"   la	  %2,256(%2)\n"
+		"3: aghi  %0,-256\n"
+		"   jnm	  2b\n"
+		"4: ex	  %0,1b-0b(%3)\n"
+		"5: slgr  %0,%0\n"
+		"6: sacf  768\n"
+		EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
+		: "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
+		: : "cc", "memory");
+	return size;
+}
+
+unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n)
+{
+	if (static_key_false(&have_mvcos))
+		return copy_in_user_mvcos(to, from, n);
+	return copy_in_user_mvc(to, from, n);
+}
+EXPORT_SYMBOL(__copy_in_user);
+
+static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
+{
+	register unsigned long reg0 asm("0") = 0x810000UL;
+	unsigned long tmp1, tmp2;
+
+	tmp1 = -4096UL;
+	asm volatile(
+		"0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
+		"   jz	  4f\n"
+		"1: algr  %0,%2\n"
+		"   slgr  %1,%2\n"
+		"   j	  0b\n"
+		"2: la	  %3,4095(%1)\n"/* %4 = to + 4095 */
+		"   nr	  %3,%2\n"	/* %4 = (to + 4095) & -4096 */
+		"   slgr  %3,%1\n"
+		"   clgr  %0,%3\n"	/* copy crosses next page boundary? */
+		"   jnh	  5f\n"
+		"3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
+		"   slgr  %0,%3\n"
+		"   j	  5f\n"
+		"4:slgr  %0,%0\n"
+		"5:\n"
+		EX_TABLE(0b,2b) EX_TABLE(3b,5b)
+		: "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
+		: "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
+	return size;
+}
+
+static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
+{
+	unsigned long tmp1, tmp2;
+
+	load_kernel_asce();
+	asm volatile(
+		"   sacf  256\n"
+		"   aghi  %0,-1\n"
+		"   jo    5f\n"
+		"   bras  %3,3f\n"
+		"   xc    0(1,%1),0(%1)\n"
+		"0: aghi  %0,257\n"
+		"   la    %2,255(%1)\n" /* %2 = ptr + 255 */
+		"   srl   %2,12\n"
+		"   sll   %2,12\n"	/* %2 = (ptr + 255) & -4096 */
+		"   slgr  %2,%1\n"
+		"   clgr  %0,%2\n"	/* clear crosses next page boundary? */
+		"   jnh   5f\n"
+		"   aghi  %2,-1\n"
+		"1: ex    %2,0(%3)\n"
+		"   aghi  %2,1\n"
+		"   slgr  %0,%2\n"
+		"   j     5f\n"
+		"2: xc    0(256,%1),0(%1)\n"
+		"   la    %1,256(%1)\n"
+		"3: aghi  %0,-256\n"
+		"   jnm   2b\n"
+		"4: ex    %0,0(%3)\n"
+		"5: slgr  %0,%0\n"
+		"6: sacf  768\n"
+		EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
+		: "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
+		: : "cc", "memory");
+	return size;
+}
+
+unsigned long __clear_user(void __user *to, unsigned long size)
+{
+	if (static_key_false(&have_mvcos))
+			return clear_user_mvcos(to, size);
+	return clear_user_xc(to, size);
+}
+EXPORT_SYMBOL(__clear_user);
+
+static inline unsigned long strnlen_user_srst(const char __user *src,
+					      unsigned long size)
+{
+	register unsigned long reg0 asm("0") = 0;
+	unsigned long tmp1, tmp2;
+
+	asm volatile(
+		"   la    %2,0(%1)\n"
+		"   la    %3,0(%0,%1)\n"
+		"   slgr  %0,%0\n"
+		"   sacf  256\n"
+		"0: srst  %3,%2\n"
+		"   jo    0b\n"
+		"   la    %0,1(%3)\n"	/* strnlen_user results includes \0 */
+		"   slgr  %0,%1\n"
+		"1: sacf  768\n"
+		EX_TABLE(0b,1b)
+		: "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
+		: "d" (reg0) : "cc", "memory");
+	return size;
+}
+
+unsigned long __strnlen_user(const char __user *src, unsigned long size)
+{
+	if (unlikely(!size))
+		return 0;
+	load_kernel_asce();
+	return strnlen_user_srst(src, size);
+}
+EXPORT_SYMBOL(__strnlen_user);
+
+long __strncpy_from_user(char *dst, const char __user *src, long size)
+{
+	size_t done, len, offset, len_str;
+
+	if (unlikely(size <= 0))
+		return 0;
+	done = 0;
+	do {
+		offset = (size_t)src & ~PAGE_MASK;
+		len = min(size - done, PAGE_SIZE - offset);
+		if (copy_from_user(dst, src, len))
+			return -EFAULT;
+		len_str = strnlen(dst, len);
+		done += len_str;
+		src += len_str;
+		dst += len_str;
+	} while ((len_str == len) && (done < size));
+	return done;
+}
+EXPORT_SYMBOL(__strncpy_from_user);
+
+/*
+ * The "old" uaccess variant without mvcos can be enforced with the
+ * uaccess_primary kernel parameter. This is mainly for debugging purposes.
+ */
+static int uaccess_primary __initdata;
+
+static int __init parse_uaccess_pt(char *__unused)
+{
+	uaccess_primary = 1;
+	return 0;
+}
+early_param("uaccess_primary", parse_uaccess_pt);
+
+static int __init uaccess_init(void)
+{
+	if (!uaccess_primary && test_facility(27))
+		static_key_slow_inc(&have_mvcos);
+	return 0;
+}
+early_initcall(uaccess_init);