x86: apic - introduce dummy apic operations
Impact: refactor, speed up and robustize code
In case if apic was disabled by kernel option
or by hardware limits we can use dummy operations
in apic->write to simplify the ack_APIC_irq() code.
At the lame time the patch fixes the missed EOI in
do_IRQ function (which has place if kernel is compiled
as X86-32 and interrupt without handler happens where
apic was not asked to be disabled via kernel option).
Note that native_apic_write_dummy() consists of
WARN_ON_ONCE to catch any buggy writes on enabled
APICs. Could be removed after some time of testing.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090412165058.724788431@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 6603492..fd57bf3 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -27,7 +27,6 @@
if (printk_ratelimit())
pr_err("unexpected IRQ trap at vector %02x\n", irq);
-#ifdef CONFIG_X86_LOCAL_APIC
/*
* Currently unexpected vectors happen only on SMP and APIC.
* We _must_ ack these because every local APIC has only N
@@ -37,9 +36,7 @@
* completely.
* But only ack when the APIC is enabled -AK
*/
- if (cpu_has_apic)
- ack_APIC_irq();
-#endif
+ ack_APIC_irq();
}
#define irq_stats(x) (&per_cpu(irq_stat, x))
@@ -214,10 +211,7 @@
irq = __get_cpu_var(vector_irq)[vector];
if (!handle_irq(irq, regs)) {
-#ifdef CONFIG_X86_64
- if (!disable_apic)
- ack_APIC_irq();
-#endif
+ ack_APIC_irq();
if (printk_ratelimit())
pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",