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authorSrikant Patnaik2015-01-13 15:08:24 +0530
committerSrikant Patnaik2015-01-13 15:08:24 +0530
commit97327692361306d1e6259021bc425e32832fdb50 (patch)
treefe9088f3248ec61e24f404f21b9793cb644b7f01 /arch/x86/lib/rwlock.S
parent2d05a8f663478a44e088d122e0d62109bbc801d0 (diff)
parenta3a8b90b61e21be3dde9101c4e86c881e0f06210 (diff)
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dirty fix to merging
Diffstat (limited to 'arch/x86/lib/rwlock.S')
-rw-r--r--arch/x86/lib/rwlock.S44
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/x86/lib/rwlock.S b/arch/x86/lib/rwlock.S
new file mode 100644
index 00000000..1cad2213
--- /dev/null
+++ b/arch/x86/lib/rwlock.S
@@ -0,0 +1,44 @@
+/* Slow paths of read/write spinlocks. */
+
+#include <linux/linkage.h>
+#include <asm/alternative-asm.h>
+#include <asm/frame.h>
+#include <asm/rwlock.h>
+
+#ifdef CONFIG_X86_32
+# define __lock_ptr eax
+#else
+# define __lock_ptr rdi
+#endif
+
+ENTRY(__write_lock_failed)
+ CFI_STARTPROC
+ FRAME
+0: LOCK_PREFIX
+ WRITE_LOCK_ADD($RW_LOCK_BIAS) (%__lock_ptr)
+1: rep; nop
+ cmpl $WRITE_LOCK_CMP, (%__lock_ptr)
+ jne 1b
+ LOCK_PREFIX
+ WRITE_LOCK_SUB($RW_LOCK_BIAS) (%__lock_ptr)
+ jnz 0b
+ ENDFRAME
+ ret
+ CFI_ENDPROC
+END(__write_lock_failed)
+
+ENTRY(__read_lock_failed)
+ CFI_STARTPROC
+ FRAME
+0: LOCK_PREFIX
+ READ_LOCK_SIZE(inc) (%__lock_ptr)
+1: rep; nop
+ READ_LOCK_SIZE(cmp) $1, (%__lock_ptr)
+ js 1b
+ LOCK_PREFIX
+ READ_LOCK_SIZE(dec) (%__lock_ptr)
+ js 0b
+ ENDFRAME
+ ret
+ CFI_ENDPROC
+END(__read_lock_failed)