Commit 8aef36da authored by Al Viro's avatar Al Viro

x86: don't reload after cmpxchg in unsafe_atomic_op2() loop

lock cmpxchg leaves the current value in eax; no need to reload it.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 0ec33c01
......@@ -34,17 +34,17 @@ do { \
do { \
int oldval = 0, ret, tem; \
asm volatile("1:\tmovl %2, %0\n" \
"\tmovl\t%0, %3\n" \
"2:\tmovl\t%0, %3\n" \
"\t" insn "\n" \
"2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
"\tjnz\t1b\n" \
"3:\n" \
"3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
"\tjnz\t2b\n" \
"4:\n" \
"\t.section .fixup,\"ax\"\n" \
"4:\tmov\t%5, %1\n" \
"\tjmp\t3b\n" \
"5:\tmov\t%5, %1\n" \
"\tjmp\t4b\n" \
"\t.previous\n" \
_ASM_EXTABLE_UA(1b, 4b) \
_ASM_EXTABLE_UA(2b, 4b) \
_ASM_EXTABLE_UA(1b, 5b) \
_ASM_EXTABLE_UA(3b, 5b) \
: "=&a" (oldval), "=&r" (ret), \
"+m" (*uaddr), "=&r" (tem) \
: "r" (oparg), "i" (-EFAULT), "1" (0)); \
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment