Commit d15512f4 authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
Browse files

[PATCH] i386: 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: default avatarAndi Kleen <ak@suse.de>
parent e6536c12

arch/i386/kernel/io_apic.c

+11 −5
Original line number Diff line number Diff line
@@ -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)

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);

}



static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)

{

	unsigned long flags;

	spin_lock_irqsave(&ioapic_lock, flags);

	__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);