linux-kernel - [PATCH] x86: fix dummy apic read/write warning

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Date:	Sat, 06 Jun 2009 15:16:38 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>
CC:	Cyrill Gorcunov <gorcunov@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] x86: fix dummy apic read/write warning

ingo got
[    0.000000] Using APIC driver default
[    0.000000] SMP: Allowing 1 CPUs, 0 hotplug CPUs
[    0.000000] Local APIC disabled by BIOS -- you can enable it with "lapic"
[    0.000000] APIC: disable apic facility
[    0.000000] ------------[ cut here ]------------
[    0.000000] WARNING: at arch/x86/kernel/apic/apic.c:254 native_apic_read_dummy+0x2d/0x3b()
[    0.000000] Hardware name: HP OmniBook PC

we have wrong check in dummy read and write.
[we only test on system that have APIC with "disableapic"...]

Signed-off-by: yinghai Lu <yinghai@...nel.org>

---
 arch/x86/kernel/apic/apic.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6/arch/x86/kernel/apic/apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/apic.c
+++ linux-2.6/arch/x86/kernel/apic/apic.c
@@ -246,12 +246,12 @@ static int modern_apic(void)
  */
 static void native_apic_write_dummy(u32 reg, u32 v)
 {
-	WARN_ON_ONCE((cpu_has_apic || !disable_apic));
+	WARN_ON_ONCE((cpu_has_apic && !disable_apic));
 }
 
 static u32 native_apic_read_dummy(u32 reg)
 {
-	WARN_ON_ONCE((cpu_has_apic || !disable_apic));
+	WARN_ON_ONCE((cpu_has_apic && !disable_apic));
 	return 0;
 }
 

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