* Linus Torvalds <[EMAIL PROTECTED]> wrote:
> > I don't see this in Linus's tree, am I just missing it? Do you have
> > a git commit id?
>
> Isn't this 9d55b9923a1b7ea8193b8875c57ec940dc2ff027 (possibly with
> 2532ec6d178abc55681d049097d3dc577eaa266c on top)?
yeah.
Greg: note that this is against post-unification asm-x86/futex.h so it
wont apply to .24.
I've backported the fix to .24 - find it below. (untested but obvious)
Ingo
----------------------->
Subject: x86: replace LOCK_PREFIX in futex.h
From: Thomas Gleixner <[EMAIL PROTECTED]>
The exception fixup for the futex macros __futex_atomic_op1/2 and
futex_atomic_cmpxchg_inatomic() is missing an entry when the lock
prefix is replaced by a NOP via SMP alternatives.
Chuck Ebert tracked this down from the information provided in:
https://bugzilla.redhat.com/show_bug.cgi?id=429412
A possible solution would be to add another fixup after the
LOCK_PREFIX, so both the LOCK and NOP case have their own entry in the
exception table, but it's not really worth the trouble.
Simply replace LOCK_PREFIX with lock and keep those untouched by SMP
alternatives.
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
---
include/asm-x86/futex_32.h | 6 +++---
include/asm-x86/futex_64.h | 6 +++---
2 files changed, 6 insertions(+), 6 deletions(-)
Index: linux-2.6.24/include/asm-x86/futex_32.h
===================================================================
--- linux-2.6.24.orig/include/asm-x86/futex_32.h
+++ linux-2.6.24/include/asm-x86/futex_32.h
@@ -28,7 +28,7 @@
"1: movl %2, %0\n\
movl %0, %3\n" \
insn "\n" \
-"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\
+"2: lock; cmpxchgl %3, %2\n \
jnz 1b\n\
3: .section .fixup,\"ax\"\n\
4: mov %5, %1\n\
@@ -68,7 +68,7 @@ futex_atomic_op_inuser (int encoded_op,
#endif
switch (op) {
case FUTEX_OP_ADD:
- __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret,
+ __futex_atomic_op1("lock; xaddl %0, %2", ret, oldval,
oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
@@ -111,8 +111,8 @@ futex_atomic_cmpxchg_inatomic(int __user
return -EFAULT;
__asm__ __volatile__(
- "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n"
+ "1: lock; cmpxchgl %3, %1 \n"
"2: .section .fixup, \"ax\" \n"
"3: mov %2, %0 \n"
" jmp 2b \n"
Index: linux-2.6.24/include/asm-x86/futex_64.h
===================================================================
--- linux-2.6.24.orig/include/asm-x86/futex_64.h
+++ linux-2.6.24/include/asm-x86/futex_64.h
@@ -27,7 +27,7 @@
"1: movl %2, %0\n\
movl %0, %3\n" \
insn "\n" \
-"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\
+"2: lock; cmpxchgl %3, %2\n \
jnz 1b\n\
3: .section .fixup,\"ax\"\n\
4: mov %5, %1\n\
@@ -62,7 +62,7 @@ futex_atomic_op_inuser (int encoded_op,
__futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
- __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
+ __futex_atomic_op1("lock; xaddl %0, %2", ret, oldval,
uaddr, oparg);
break;
case FUTEX_OP_OR:
@@ -101,8 +101,8 @@ futex_atomic_cmpxchg_inatomic(int __user
return -EFAULT;
__asm__ __volatile__(
- "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n"
+ "1: lock; cmpxchgl %3, %1 \n"
"2: .section .fixup, \"ax\" \n"
"3: mov %2, %0 \n"
" jmp 2b \n"
--
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