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* [PATCH 1/2] locking/atomic/x86: Use ALT_OUTPUT_SP() for __alternative_atomic64()
@ 2024-10-24 18:05 Uros Bizjak
  2024-10-24 18:05 ` [PATCH 2/2] locking/atomic/x86: Use ALT_OUTPUT_SP() for __arch_{,try_}cmpxchg64_emu() Uros Bizjak
  0 siblings, 1 reply; 2+ messages in thread
From: Uros Bizjak @ 2024-10-24 18:05 UTC (permalink / raw)
  To: x86, linux-kernel
  Cc: Uros Bizjak, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	Dave Hansen, H. Peter Anvin

CONFIG_X86_CMPXCHG64 variant of x86_32 __alternative_atomic64()
macro uses CALL instruction inside asm statement. Use
ALT_OUTPUT_SP() macro to add required dependence on %esp register.

Fixes: 819165fb34b9 ("x86: Adjust asm constraints in atomic64 wrappers")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/include/asm/atomic64_32.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 1f650b4dde50..6c6e9b9f98a4 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -51,7 +51,8 @@ static __always_inline s64 arch_atomic64_read_nonatomic(const atomic64_t *v)
 #ifdef CONFIG_X86_CMPXCHG64
 #define __alternative_atomic64(f, g, out, in...) \
 	asm volatile("call %c[func]" \
-		     : out : [func] "i" (atomic64_##g##_cx8), ## in)
+		     : ALT_OUTPUT_SP(out) \
+		     : [func] "i" (atomic64_##g##_cx8), ## in)
 
 #define ATOMIC64_DECL(sym) ATOMIC64_DECL_ONE(sym##_cx8)
 #else
-- 
2.42.0


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* [PATCH 2/2] locking/atomic/x86: Use ALT_OUTPUT_SP() for __arch_{,try_}cmpxchg64_emu()
  2024-10-24 18:05 [PATCH 1/2] locking/atomic/x86: Use ALT_OUTPUT_SP() for __alternative_atomic64() Uros Bizjak
@ 2024-10-24 18:05 ` Uros Bizjak
  0 siblings, 0 replies; 2+ messages in thread
From: Uros Bizjak @ 2024-10-24 18:05 UTC (permalink / raw)
  To: x86, linux-kernel
  Cc: Uros Bizjak, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	Dave Hansen, H. Peter Anvin

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@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/include/asm/cmpxchg_32.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index 62cef2113ca7..fd1282a783dd 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");					\
 									\
-- 
2.42.0


^ permalink raw reply related	[flat|nested] 2+ messages in thread

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2024-10-24 18:05 ` [PATCH 2/2] locking/atomic/x86: Use ALT_OUTPUT_SP() for __arch_{,try_}cmpxchg64_emu() Uros Bizjak

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