x86: Simplify timer_ack magic in time_32.c
Let the compiler optimize the timer_ack magic away in the 32bit timer
interrupt and put the same code into time_64.c. It's optimized out for
CONFIG_X86_IO_APIC on 32bit and for 64bit because timer_ack is const 0
in both cases.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/time_32.c b/arch/x86/kernel/time_32.c
index acbaefd..7a26bcf 100644
--- a/arch/x86/kernel/time_32.c
+++ b/arch/x86/kernel/time_32.c
@@ -23,7 +23,9 @@
#include <asm/time.h>
#include <asm/nmi.h>
+#if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
int timer_ack;
+#endif
unsigned long profile_pc(struct pt_regs *regs)
{
@@ -60,7 +62,7 @@
/* Keep nmi watchdog up to date */
inc_irq_stat(irq0_irqs);
-#ifdef CONFIG_X86_IO_APIC
+ /* Optimized out for !IO_APIC and x86_64 */
if (timer_ack) {
/*
* Subtle, when I/O APICs are used we have to ack timer IRQ
@@ -73,7 +75,6 @@
inb(PIC_MASTER_POLL);
spin_unlock(&i8259A_lock);
}
-#endif
global_clock_event->event_handler(global_clock_event);
diff --git a/arch/x86/kernel/time_64.c b/arch/x86/kernel/time_64.c
index 45914f8..35e0a92 100644
--- a/arch/x86/kernel/time_64.c
+++ b/arch/x86/kernel/time_64.c
@@ -51,6 +51,20 @@
{
inc_irq_stat(irq0_irqs);
+ /* Optimized out for !IO_APIC and x86_64 */
+ if (timer_ack) {
+ /*
+ * Subtle, when I/O APICs are used we have to ack timer IRQ
+ * manually to deassert NMI lines for the watchdog if run
+ * on an 82489DX-based system.
+ */
+ spin_lock(&i8259A_lock);
+ outb(0x0c, PIC_MASTER_OCW3);
+ /* Ack the IRQ; AEOI will end it automatically. */
+ inb(PIC_MASTER_POLL);
+ spin_unlock(&i8259A_lock);
+ }
+
global_clock_event->event_handler(global_clock_event);
#ifdef CONFIG_MCA