1 files changed, 272 insertions, 0 deletions
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);