[PATCH] x86/pvqspinlock: Use LOCK_PREFIX in __pv_queued_spin_unlock assembly code

From: Waiman Long
Date: Tue Jul 17 2018 - 16:16:20 EST


The LOCK_PREFIX macro should be used in the assembly
__raw_callee_save___pv_queued_spin_unlock code so that the lock prefix
can be patched out on UP systems.

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
arch/x86/include/asm/qspinlock_paravirt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 9ef5ee0..159622e 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -43,7 +43,7 @@
"push %rdx;"
"mov $0x1,%eax;"
"xor %edx,%edx;"
- "lock cmpxchg %dl,(%rdi);"
+ LOCK_PREFIX "cmpxchg %dl,(%rdi);"
"cmp $0x1,%al;"
"jne .slowpath;"
"pop %rdx;"
--
1.8.3.1