This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / x86_64 / lib / rwlock.S

diff --git a/arch/x86_64/lib/rwlock.S b/arch/x86_64/lib/rwlock.S
new file mode 100644 (file)
index 0000000..0cde1f8
--- /dev/null
+++ b/arch/x86_64/lib/rwlock.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)