From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001
From: root <root@artemis.panaceas.org>
Date: Fri, 25 Dec 2015 04:40:36 +0000
Subject: initial_commit

---
 arch/alpha/include/asm/spinlock.h | 176 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 arch/alpha/include/asm/spinlock.h

(limited to 'arch/alpha/include/asm/spinlock.h')

diff --git a/arch/alpha/include/asm/spinlock.h b/arch/alpha/include/asm/spinlock.h
new file mode 100644
index 00000000..d0faca1e
--- /dev/null
+++ b/arch/alpha/include/asm/spinlock.h
@@ -0,0 +1,176 @@
+#ifndef _ALPHA_SPINLOCK_H
+#define _ALPHA_SPINLOCK_H
+
+#include <asm/system.h>
+#include <linux/kernel.h>
+#include <asm/current.h>
+
+/*
+ * Simple spin lock operations.  There are two variants, one clears IRQ's
+ * on the local processor, one does not.
+ *
+ * We make no fairness assumptions. They have a cost.
+ */
+
+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
+#define arch_spin_is_locked(x)	((x)->lock != 0)
+#define arch_spin_unlock_wait(x) \
+		do { cpu_relax(); } while ((x)->lock)
+
+static inline void arch_spin_unlock(arch_spinlock_t * lock)
+{
+	mb();
+	lock->lock = 0;
+}
+
+static inline void arch_spin_lock(arch_spinlock_t * lock)
+{
+	long tmp;
+
+	__asm__ __volatile__(
+	"1:	ldl_l	%0,%1\n"
+	"	bne	%0,2f\n"
+	"	lda	%0,1\n"
+	"	stl_c	%0,%1\n"
+	"	beq	%0,2f\n"
+	"	mb\n"
+	".subsection 2\n"
+	"2:	ldl	%0,%1\n"
+	"	bne	%0,2b\n"
+	"	br	1b\n"
+	".previous"
+	: "=&r" (tmp), "=m" (lock->lock)
+	: "m"(lock->lock) : "memory");
+}
+
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+	return !test_and_set_bit(0, &lock->lock);
+}
+
+/***********************************************************/
+
+static inline int arch_read_can_lock(arch_rwlock_t *lock)
+{
+	return (lock->lock & 1) == 0;
+}
+
+static inline int arch_write_can_lock(arch_rwlock_t *lock)
+{
+	return lock->lock == 0;
+}
+
+static inline void arch_read_lock(arch_rwlock_t *lock)
+{
+	long regx;
+
+	__asm__ __volatile__(
+	"1:	ldl_l	%1,%0\n"
+	"	blbs	%1,6f\n"
+	"	subl	%1,2,%1\n"
+	"	stl_c	%1,%0\n"
+	"	beq	%1,6f\n"
+	"	mb\n"
+	".subsection 2\n"
+	"6:	ldl	%1,%0\n"
+	"	blbs	%1,6b\n"
+	"	br	1b\n"
+	".previous"
+	: "=m" (*lock), "=&r" (regx)
+	: "m" (*lock) : "memory");
+}
+
+static inline void arch_write_lock(arch_rwlock_t *lock)
+{
+	long regx;
+
+	__asm__ __volatile__(
+	"1:	ldl_l	%1,%0\n"
+	"	bne	%1,6f\n"
+	"	lda	%1,1\n"
+	"	stl_c	%1,%0\n"
+	"	beq	%1,6f\n"
+	"	mb\n"
+	".subsection 2\n"
+	"6:	ldl	%1,%0\n"
+	"	bne	%1,6b\n"
+	"	br	1b\n"
+	".previous"
+	: "=m" (*lock), "=&r" (regx)
+	: "m" (*lock) : "memory");
+}
+
+static inline int arch_read_trylock(arch_rwlock_t * lock)
+{
+	long regx;
+	int success;
+
+	__asm__ __volatile__(
+	"1:	ldl_l	%1,%0\n"
+	"	lda	%2,0\n"
+	"	blbs	%1,2f\n"
+	"	subl	%1,2,%2\n"
+	"	stl_c	%2,%0\n"
+	"	beq	%2,6f\n"
+	"2:	mb\n"
+	".subsection 2\n"
+	"6:	br	1b\n"
+	".previous"
+	: "=m" (*lock), "=&r" (regx), "=&r" (success)
+	: "m" (*lock) : "memory");
+
+	return success;
+}
+
+static inline int arch_write_trylock(arch_rwlock_t * lock)
+{
+	long regx;
+	int success;
+
+	__asm__ __volatile__(
+	"1:	ldl_l	%1,%0\n"
+	"	lda	%2,0\n"
+	"	bne	%1,2f\n"
+	"	lda	%2,1\n"
+	"	stl_c	%2,%0\n"
+	"	beq	%2,6f\n"
+	"2:	mb\n"
+	".subsection 2\n"
+	"6:	br	1b\n"
+	".previous"
+	: "=m" (*lock), "=&r" (regx), "=&r" (success)
+	: "m" (*lock) : "memory");
+
+	return success;
+}
+
+static inline void arch_read_unlock(arch_rwlock_t * lock)
+{
+	long regx;
+	__asm__ __volatile__(
+	"	mb\n"
+	"1:	ldl_l	%1,%0\n"
+	"	addl	%1,2,%1\n"
+	"	stl_c	%1,%0\n"
+	"	beq	%1,6f\n"
+	".subsection 2\n"
+	"6:	br	1b\n"
+	".previous"
+	: "=m" (*lock), "=&r" (regx)
+	: "m" (*lock) : "memory");
+}
+
+static inline void arch_write_unlock(arch_rwlock_t * lock)
+{
+	mb();
+	lock->lock = 0;
+}
+
+#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
+#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
+
+#define arch_spin_relax(lock)	cpu_relax()
+#define arch_read_relax(lock)	cpu_relax()
+#define arch_write_relax(lock)	cpu_relax()
+
+#endif /* _ALPHA_SPINLOCK_H */
-- 
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