linux-kernel - [tip:x86/urgent] x86: Fix bogus warning in apic_noop.apic

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Message-ID: <tip-a946d8f11f0da9cfc714248036fcfd3a794d1e27@git.kernel.org>
Date:	Mon, 7 Dec 2009 12:18:37 GMT
From:	tip-bot for Thomas Gleixner <tglx@...utronix.de>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	gorcunov@...nvz.org, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:x86/urgent] x86: Fix bogus warning in apic_noop.apic_write()

Commit-ID:  a946d8f11f0da9cfc714248036fcfd3a794d1e27
Gitweb:     http://git.kernel.org/tip/a946d8f11f0da9cfc714248036fcfd3a794d1e27
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 7 Dec 2009 12:59:46 +0100
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Mon, 7 Dec 2009 13:16:37 +0100

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.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Cyrill Gorcunov <gorcunov@...nvz.org>
Cc: <stable@...nel.org> # in <= .32 this typo resides in native_apic_write_dummy()
LKML-Reference: <alpine.LFD.2.00.0912071255420.3089@...alhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/kernel/apic/apic_noop.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/apic/apic_noop.c b/arch/x86/kernel/apic/apic_noop.c
index d9acc3b..e31b9ff 100644
--- a/arch/x86/kernel/apic/apic_noop.c
+++ b/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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