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[PATCH] x86-64: Fix race in IO-APIC routing entry setup. 

Interrupt could happen between setting the IO-APIC entry
and setting its interrupt data.

Pointed out by Linus.

Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Andi Kleen 2006-12-07 02:14:07 +01:00 committed by Andi Kleen
parent d15512f442
commit 516d283643
1 changed files with 10 additions and 4 deletions
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14
arch/x86_64/kernel/io_apic.c
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@ -174,14 +174,20 @@ static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin)
* the interrupt, and we need to make sure the entry is fully populated
* before that happens.
*/
static void
__ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
{
union entry_union eu;
eu.entry = e;
io_apic_write(apic, 0x11 + 2*pin, eu.w2);
io_apic_write(apic, 0x10 + 2*pin, eu.w1);
}
static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
{
unsigned long flags;
union entry_union eu;
eu.entry = e;
spin_lock_irqsave(&ioapic_lock, flags);
io_apic_write(apic, 0x11 + 2*pin, eu.w2);
io_apic_write(apic, 0x10 + 2*pin, eu.w1);
__ioapic_write_entry(apic, pin, e);
spin_unlock_irqrestore(&ioapic_lock, flags);
}