From 185f3d38900f750a4566f87cde6a178f3595a115 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 11 Oct 2007 11:17:08 +0200
Subject: x86_64: move lib

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/lib/rwlock_64.S | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 arch/x86/lib/rwlock_64.S

(limited to 'arch/x86/lib/rwlock_64.S')

diff --git a/arch/x86/lib/rwlock_64.S b/arch/x86/lib/rwlock_64.S
new file mode 100644
index 0000000..0cde1f8
--- /dev/null
+++ b/arch/x86/lib/rwlock_64.S
@@ -0,0 +1,38 @@
+/* Slow paths of read/write spinlocks. */
+
+#include <linux/linkage.h>
+#include <asm/rwlock.h>
+#include <asm/alternative-asm.i>
+#include <asm/dwarf2.h>
+
+/* rdi:	pointer to rwlock_t */
+ENTRY(__write_lock_failed)
+	CFI_STARTPROC
+	LOCK_PREFIX
+	addl $RW_LOCK_BIAS,(%rdi)
+1:	rep
+	nop
+	cmpl $RW_LOCK_BIAS,(%rdi)
+	jne 1b
+	LOCK_PREFIX
+	subl $RW_LOCK_BIAS,(%rdi)
+	jnz  __write_lock_failed
+	ret
+	CFI_ENDPROC
+END(__write_lock_failed)
+
+/* rdi:	pointer to rwlock_t */
+ENTRY(__read_lock_failed)
+	CFI_STARTPROC
+	LOCK_PREFIX
+	incl (%rdi)
+1:	rep
+	nop
+	cmpl $1,(%rdi)
+	js 1b
+	LOCK_PREFIX
+	decl (%rdi)
+	js __read_lock_failed
+	ret
+	CFI_ENDPROC
+END(__read_lock_failed)
-- 
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