diff options
| author | Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> | 2008-08-15 12:56:59 -0400 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-08-15 12:51:11 -0700 |
| commit | 5bbd4c3724008c93cf3efdfc38a3402e245ab506 (patch) | |
| tree | 5b74f2b70396f2cf808b368d415ae444fe94bfac | |
| parent | 1f49a2c2aeb22d5abc6d4ea574ff63d37ca55fbe (diff) | |
x86: spinlock use LOCK_PREFIX
Since we are now using DS prefixes instead of NOP to remove LOCK
prefixes, there is no longer any problems with instruction boundaries
moving around.
* Linus Torvalds (torvalds@linux-foundation.org) wrote:
>
>
> 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
Unless there a rationale for this, I think these be changed to LOCK_PREFIX
too.
grep "lock ;" include/asm-x86/spinlock.h
"lock ; cmpxchgw %w1,%2\n\t"
asm volatile("lock ; xaddl %0, %1\n"
"lock ; cmpxchgl %1,%2\n\t"
Applies to 2.6.27-rc2.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: H. Peter Anvin <hpa@zytor.com>
CC: Jeremy Fitzhardinge <jeremy@goop.org>
CC: Roland McGrath <roland@redhat.com>
CC: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
CC: Steven Rostedt <srostedt@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: David Miller <davem@davemloft.net>
CC: Ulrich Drepper <drepper@redhat.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Gregory Haskins <ghaskins@novell.com>
CC: Arnaldo Carvalho de Melo <acme@redhat.com>
CC: "Luis Claudio R. Goncalves" <lclaudio@uudg.org>
CC: Clark Williams <williams@redhat.com>
CC: Christoph Lameter <cl@linux-foundation.org>
CC: Andi Kleen <andi@firstfloor.org>
CC: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| -rw-r--r-- | include/asm-x86/spinlock.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/asm-x86/spinlock.h b/include/asm-x86/spinlock.h index 4f9a9861799a..0b4d59a93d23 100644 --- a/include/asm-x86/spinlock.h +++ b/include/asm-x86/spinlock.h @@ -97,7 +97,7 @@ static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock) "jne 1f\n\t" "movw %w0,%w1\n\t" "incb %h1\n\t" - "lock ; cmpxchgw %w1,%2\n\t" + LOCK_PREFIX "cmpxchgw %w1,%2\n\t" "1:" "sete %b1\n\t" "movzbl %b1,%0\n\t" @@ -135,7 +135,7 @@ static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) int inc = 0x00010000; int tmp; - asm volatile("lock ; xaddl %0, %1\n" + asm volatile(LOCK_PREFIX "xaddl %0, %1\n" "movzwl %w0, %2\n\t" "shrl $16, %0\n\t" "1:\t" @@ -162,7 +162,7 @@ static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock) "cmpl %0,%1\n\t" "jne 1f\n\t" "addl $0x00010000, %1\n\t" - "lock ; cmpxchgl %1,%2\n\t" + LOCK_PREFIX "cmpxchgl %1,%2\n\t" "1:" "sete %b1\n\t" "movzbl %b1,%0\n\t" |