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x86: don't disable the APIC if it hasn't been mapped yet 

When the kernel panics early for some unrelated reason
there would be eventually an early exception inside panic because
clear_local_APIC tried to disable the not yet mapped APIC.
Check for that explicitely.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Andi Kleen 2008-01-30 13:33:17 +01:00 committed by Ingo Molnar
parent ca74a6f84e
commit d3432896da
2 changed files with 15 additions and 5 deletions
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11
arch/x86/kernel/apic_32.c
View File

@ -99,6 +99,8 @@ static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
/* Local APIC was disabled by the BIOS and enabled by the kernel */
static int enabled_via_apicbase;
static unsigned long apic_phys;
/*
* Get the LAPIC version
*/
@ -631,9 +633,14 @@ int setup_profiling_timer(unsigned int multiplier)
*/
void clear_local_APIC(void)
{
int maxlvt = lapic_get_maxlvt();
int maxlvt;
u32 v;
/* APIC hasn't been mapped yet */
if (!apic_phys)
return;
maxlvt = lapic_get_maxlvt();
/*
* Masking an LVT entry can trigger a local APIC error
* if the vector is zero. Mask LVTERR first to prevent this.
@ -1120,8 +1127,6 @@ no_apic:
*/
void __init init_apic_mappings(void)
{
unsigned long apic_phys;
/*
* If no local APIC can be found then set up a fake all
* zeroes page to simulate the local APIC and another

9
arch/x86/kernel/apic_64.c
View File

@ -81,6 +81,8 @@ static struct clock_event_device lapic_clockevent = {
};
static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
static unsigned long apic_phys;
/*
* Get the LAPIC version
*/
@ -525,6 +527,11 @@ void clear_local_APIC(void)
int maxlvt = lapic_get_maxlvt();
u32 v;
/* APIC hasn't been mapped yet */
if (!apic_phys)
return;
maxlvt = lapic_get_maxlvt();
/*
* Masking an LVT entry can trigger a local APIC error
* if the vector is zero. Mask LVTERR first to prevent this.
@ -859,8 +866,6 @@ static int __init detect_init_APIC(void)
*/
void __init init_apic_mappings(void)
{
unsigned long apic_phys;
/*
* If no local APIC can be found then set up a fake all
* zeroes page to simulate the local APIC and another