From 516d2836434d279fef164bb1b964e83425d312d2 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 7 Dec 2006 02:14:07 +0100 Subject: [PATCH] [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 --- arch/x86_64/kernel/io_apic.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c index 88fcc4ebbf6..eaf0b708e67 100644 --- a/arch/x86_64/kernel/io_apic.c +++ b/arch/x86_64/kernel/io_apic.c @@ -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); }