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Commit d3432896 authored by Andi Kleen's avatar Andi Kleen Committed by Ingo Molnar
Browse files

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: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent ca74a6f8

arch/x86/kernel/apic_32.c

+8 −3
Original line number Original line Diff line number Diff line
@@ -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 */

/* Local APIC was disabled by the BIOS and enabled by the kernel */

static int enabled_via_apicbase;

static int enabled_via_apicbase;





static unsigned long apic_phys;



/*

/*

 * Get the LAPIC version

 * Get the LAPIC version

 */

 */
@@ -631,9 +633,14 @@ int setup_profiling_timer(unsigned int multiplier) 
 */

 */

void clear_local_APIC(void)

void clear_local_APIC(void)

{

{

	int maxlvt = lapic_get_maxlvt();

	int maxlvt;

	u32 v;

	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

	 * Masking an LVT entry can trigger a local APIC error

	 * if the vector is zero. Mask LVTERR first to prevent this.

	 * if the vector is zero. Mask LVTERR first to prevent this.
@@ -1120,8 +1127,6 @@ static int __init detect_init_APIC(void) 
 */

 */

void __init init_apic_mappings(void)

void __init init_apic_mappings(void)

{

{

	unsigned long apic_phys;



	/*

	/*

	 * If no local APIC can be found then set up a fake all

	 * If no local APIC can be found then set up a fake all

	 * zeroes page to simulate the local APIC and another

	 * zeroes page to simulate the local APIC and another

arch/x86/kernel/apic_64.c

+7 −2
Original line number Original line Diff line number Diff line
@@ -81,6 +81,8 @@ static struct clock_event_device lapic_clockevent = { 
};

};

static DEFINE_PER_CPU(struct clock_event_device, lapic_events);

static DEFINE_PER_CPU(struct clock_event_device, lapic_events);





static unsigned long apic_phys;



/*

/*

 * Get the LAPIC version

 * Get the LAPIC version

 */

 */
@@ -525,6 +527,11 @@ void clear_local_APIC(void) 
	int maxlvt = lapic_get_maxlvt();

	int maxlvt = lapic_get_maxlvt();

	u32 v;

	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

	 * Masking an LVT entry can trigger a local APIC error

	 * if the vector is zero. Mask LVTERR first to prevent this.

	 * 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)

void __init init_apic_mappings(void)

{

{

	unsigned long apic_phys;



	/*

	/*

	 * If no local APIC can be found then set up a fake all

	 * If no local APIC can be found then set up a fake all

	 * zeroes page to simulate the local APIC and another

	 * zeroes page to simulate the local APIC and another