linux-kernel - [PATCH] x86: Fix bogus warning in apic_noop.apic

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Message-ID: <alpine.LFD.2.00.0912071255420.3089@localhost.localdomain>
Date:	Mon, 7 Dec 2009 12:59:46 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	LKML <linux-kernel@...r.kernel.org>
cc:	x86@...nel.org, Cyrill Gorcunov <gorcunov@...nvz.org>
Subject: [PATCH] x86: Fix bogus warning in apic_noop.apic_write()

apic_noop is used to provide dummy apic functions. It's installed when
the CPU has no APIC or when the APIC is disabled on the kernel command
line.

The apic_noop implementation of apic_write() warns when the CPU has an
APIC or when the APIC is not disabled.

That's bogus. The warning should only happen when the CPU has an APIC
_AND_ the APIC is not disabled. apic_noop.apic_read() has the correct
check.

[ @stable: in <= .32 this typo resides in native_apic_write_dummy(). ]

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable@...nel.org
---
 arch/x86/kernel/apic/apic_noop.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/arch/x86/kernel/apic/apic_noop.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/apic_noop.c
+++ linux-2.6/arch/x86/kernel/apic/apic_noop.c
@@ -127,7 +127,7 @@ static u32 noop_apic_read(u32 reg)
 
 static void noop_apic_write(u32 reg, u32 v)
 {
-	WARN_ON_ONCE((cpu_has_apic || !disable_apic));
+	WARN_ON_ONCE((cpu_has_apic && !disable_apic));
 }
 
 struct apic apic_noop = {
--
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