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[PATCH] i386: Fix race in IO-APIC routing entry setup.

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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 e6536c1262
commit d15512f442
1 changed files with 12 additions and 6 deletions
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18
arch/i386/kernel/io_apic.c
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@ -153,14 +153,20 @@ 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);
}
@ -1360,8 +1366,8 @@ static void __init setup_IO_APIC_irqs(void)
if (!apic && (irq < 16))
disable_8259A_irq(irq);
}
ioapic_write_entry(apic, pin, entry);
spin_lock_irqsave(&ioapic_lock, flags);
__ioapic_write_entry(apic, pin, entry);
set_native_irq_info(irq, TARGET_CPUS);
spin_unlock_irqrestore(&ioapic_lock, flags);
}
@ -2856,8 +2862,8 @@ int io_apic_set_pci_routing (int ioapic, int pin, int irq, int edge_level, int a
if (!ioapic && (irq < 16))
disable_8259A_irq(irq);
ioapic_write_entry(ioapic, pin, entry);
spin_lock_irqsave(&ioapic_lock, flags);
__ioapic_write_entry(ioapic, pin, entry);
set_native_irq_info(irq, TARGET_CPUS);
spin_unlock_irqrestore(&ioapic_lock, flags);