diff options
| author | Mathieu Desnoyers <[email protected]> | 2008-08-15 12:45:09 -0400 |
|---|---|---|
| committer | H. Peter Anvin <[email protected]> | 2008-08-15 12:49:45 -0700 |
| commit | 1f49a2c2aeb22d5abc6d4ea574ff63d37ca55fbe (patch) | |
| tree | d559e223017b1c39ccaea3056ae3af0e62635509 | |
| parent | f88f07e0f0fd6376e081b10930d272a08fbf082f (diff) | |
x86: revert replace LOCK_PREFIX in futex.h
Since we now use DS prefixes instead of NOP to remove LOCK prefixes,
there are no longer any issues with instruction boundaries moving around.
Depends on :
x86 alternatives : fix LOCK_PREFIX race with preemptible kernel and CPU hotplug
On Thu, 14 Aug 2008, Mathieu Desnoyers wrote:
>
> Changing the 0x90 (single-byte nop) currently used into a 0x3E DS segment
> override prefix should fix this issue. Since the default of the atomic
> instructions is to use the DS segment anyway, it should not affect the
> behavior.
Ok, so I think this is an _excellent_ patch, but I'd like to also then use
LOCK_PREFIX in include/asm-x86/futex.h.
See commit 9d55b9923a1b7ea8193b8875c57ec940dc2ff027.
Linus
Applies to 2.6.27-rc2 (and -rc3 unless hell broke loose in futex.h between rc2
and rc3).
Signed-off-by: Mathieu Desnoyers <[email protected]>
CC: Linus Torvalds <[email protected]>
CC: H. Peter Anvin <[email protected]>
CC: Jeremy Fitzhardinge <[email protected]>
CC: Roland McGrath <[email protected]>
CC: Ingo Molnar <[email protected]>
Cc: Steven Rostedt <[email protected]>
CC: Steven Rostedt <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Peter Zijlstra <[email protected]>
CC: Andrew Morton <[email protected]>
CC: David Miller <[email protected]>
CC: Ulrich Drepper <[email protected]>
CC: Rusty Russell <[email protected]>
CC: Gregory Haskins <[email protected]>
CC: Arnaldo Carvalho de Melo <[email protected]>
CC: "Luis Claudio R. Goncalves" <[email protected]>
CC: Clark Williams <[email protected]>
CC: Christoph Lameter <[email protected]>
CC: Andi Kleen <[email protected]>
CC: Harvey Harrison <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
| -rw-r--r-- | include/asm-x86/futex.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/asm-x86/futex.h b/include/asm-x86/futex.h index e7a76b37b333..d1b988ce080a 100644 --- a/include/asm-x86/futex.h +++ b/include/asm-x86/futex.h @@ -25,7 +25,7 @@ asm volatile("1:\tmovl %2, %0\n" \ "\tmovl\t%0, %3\n" \ "\t" insn "\n" \ - "2:\tlock; cmpxchgl %3, %2\n" \ + "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \ "\tjnz\t1b\n" \ "3:\t.section .fixup,\"ax\"\n" \ "4:\tmov\t%5, %1\n" \ @@ -64,7 +64,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr) __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg); break; case FUTEX_OP_ADD: - __futex_atomic_op1("lock; xaddl %0, %2", ret, oldval, + __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval, uaddr, oparg); break; case FUTEX_OP_OR: @@ -122,7 +122,7 @@ static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) return -EFAULT; - asm volatile("1:\tlock; cmpxchgl %3, %1\n" + asm volatile("1:\t" LOCK_PREFIX "cmpxchgl %3, %1\n" "2:\t.section .fixup, \"ax\"\n" "3:\tmov %2, %0\n" "\tjmp 2b\n" |