[PATCH resend -tip] x86,mcheck: Thermal monitoring depends on APICbeing enabled

From: Cyrill Gorcunov
Date: Sat Dec 12 2009 - 21:10:05 EST


Add check if APIC is not disabled since thermal
monitoring depends on it. As only apic gets disabled
we should not try to install "thermal monitor" vector,
print out that thermal monitoring is enabled and etc...

Note that "Intel Correct Machine Check Interrupts" already
has such a check.

Also I decided to not add cpu_has_apic check into mcheck_intel_therm_init
since even if it'll call apic_read on disabled apic -- it's safe
here and allow us to save a few code bytes.

Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
---

Please review. This should close a number of WARNs triggered
by intel_init_thermal when apic gets disabled state.

Ie the WARNs like

http://kerneloops.org/oops.php?number=974702

arch/x86/kernel/cpu/mcheck/therm_throt.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux-2.6.git/arch/x86/kernel/cpu/mcheck/therm_throt.c
=====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ linux-2.6.git/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -274,8 +274,9 @@ void intel_init_thermal(struct cpuinfo_x
int tm2 = 0;
u32 l, h;

- /* Thermal monitoring depends on ACPI and clock modulation*/
- if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
+ /* Thermal monitoring depends on APIC, ACPI and clock modulation */
+ if (!cpu_has_apic || !cpu_has(c, X86_FEATURE_ACPI) ||
+ !cpu_has(c, X86_FEATURE_ACC))
return;

/*

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