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| author | Al Viro <viro@zeniv.linux.org.uk> | 2020-03-27 00:34:40 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-03-28 06:58:54 +0300 |
| commit | 8aef36dacb3a932cb77da8bb7eb21a154babd0b8 (patch) | |
| tree | dc536db1c2a979982e0f0020b114d55b3a1f4152 /arch/x86/include/asm | |
| parent | 0ec33c0171a138bedc1a39f4fd70455416dca926 (diff) | |
| download | linux-8aef36dacb3a932cb77da8bb7eb21a154babd0b8.tar.xz | |
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: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/futex.h | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h index 53c07ab63762..5ff7626a333d 100644 --- a/arch/x86/include/asm/futex.h +++ b/arch/x86/include/asm/futex.h @@ -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)); \ |