From: Pranith Kumar <bobby.prani@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT
AND 64-BIT))
Subject: [PATCH] x86: cmpxchg_double: Add missing memory clobber
Date: Tue, 6 Oct 2015 14:54:29 -0400 [thread overview]
Message-ID: <1444157670-19951-1-git-send-email-bobby.prani@gmail.com> (raw)
We are reading from memory locations pointed to by p1 and p2 in the asm
block. Add a memory clobber flag to make gcc aware of this.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
arch/x86/include/asm/cmpxchg.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index 4a2e5bc..3e83949 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -214,7 +214,8 @@ extern void __add_wrong_size(void)
: "=a" (__ret), "+d" (__old2), \
"+m" (*(p1)), "+m" (*(p2)) \
: "i" (2 * sizeof(long)), "a" (__old1), \
- "b" (__new1), "c" (__new2)); \
+ "b" (__new1), "c" (__new2) \
+ : "memory"); \
__ret; \
})
--
2.5.3
next reply other threads:[~2015-10-06 18:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-06 18:54 Pranith Kumar [this message]
2015-10-06 20:16 ` H. Peter Anvin
2015-10-06 20:29 ` Pranith Kumar
2015-10-06 21:39 ` H. Peter Anvin
2015-10-07 13:00 ` Peter Zijlstra
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