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>
diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c
index 85bd3d4..a7a38c9 100644
--- a/arch/x86/kernel/apic_64.c
+++ b/arch/x86/kernel/apic_64.c
@@ -81,6 +81,8 @@
};
static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
+static unsigned long apic_phys;
+
/*
* Get the LAPIC version
*/
@@ -525,6 +527,11 @@
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 @@
*/
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