This is a note to let you know that I've just added the patch titled
locking/atomic/x86: Use ALT_OUTPUT_SP() for __arch_{,try_}cmpxchg64_emu()
to the 6.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
locking-atomic-x86-use-alt_output_sp-for-__arch_-try.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 43475031565904994d5547d1c220805a6898fb2c
Author: Uros Bizjak <ubizjak@xxxxxxxxx>
Date: Sun Nov 3 17:09:32 2024 +0100
locking/atomic/x86: Use ALT_OUTPUT_SP() for __arch_{,try_}cmpxchg64_emu()
[ Upstream commit 25cf4fbb596d730476afcc0fb87a9d708db14078 ]
x86_32 __arch_{,try_}cmpxchg64_emu()() macros use CALL instruction
inside asm statement. Use ALT_OUTPUT_SP() macro to add required
dependence on %esp register.
Fixes: 79e1dd05d1a2 ("x86: Provide an alternative() based cmpxchg64()")
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20241103160954.3329-2-ubizjak@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index 62cef2113ca74..fd1282a783ddb 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -94,7 +94,7 @@ static __always_inline bool __try_cmpxchg64_local(volatile u64 *ptr, u64 *oldp,
asm volatile(ALTERNATIVE(_lock_loc \
"call cmpxchg8b_emu", \
_lock "cmpxchg8b %a[ptr]", X86_FEATURE_CX8) \
- : "+a" (o.low), "+d" (o.high) \
+ : ALT_OUTPUT_SP("+a" (o.low), "+d" (o.high)) \
: "b" (n.low), "c" (n.high), [ptr] "S" (_ptr) \
: "memory"); \
\
@@ -123,8 +123,8 @@ static __always_inline u64 arch_cmpxchg64_local(volatile u64 *ptr, u64 old, u64
"call cmpxchg8b_emu", \
_lock "cmpxchg8b %a[ptr]", X86_FEATURE_CX8) \
CC_SET(e) \
- : CC_OUT(e) (ret), \
- "+a" (o.low), "+d" (o.high) \
+ : ALT_OUTPUT_SP(CC_OUT(e) (ret), \
+ "+a" (o.low), "+d" (o.high)) \
: "b" (n.low), "c" (n.high), [ptr] "S" (_ptr) \
: "memory"); \
\
