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authorThomas Gleixner <tglx@linutronix.de>2009-08-20 15:54:21 +0200
committerThomas Gleixner <tglx@linutronix.de>2009-08-31 09:35:46 +0200
commit64fcbac1f38882d8ae82c44a1c2a676cfa5e79e1 (patch)
treeec1206322a8ca2a775db5ca552d5666b968be77c
parentdd3e6e8c6e7a2294f137c4dbccb3e73e7fa8ba15 (diff)
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>
-rw-r--r--arch/x86/include/asm/timer.h6
-rw-r--r--arch/x86/kernel/time_32.c5
-rw-r--r--arch/x86/kernel/time_64.c14
3 files changed, 21 insertions, 4 deletions
diff --git a/arch/x86/include/asm/timer.h b/arch/x86/include/asm/timer.h
index e854c7ab4169..65228ccc5f0d 100644
--- a/arch/x86/include/asm/timer.h
+++ b/arch/x86/include/asm/timer.h
@@ -9,11 +9,13 @@
unsigned long long native_sched_clock(void);
unsigned long native_calibrate_tsc(void);
+extern int recalibrate_cpu_khz(void);
-#ifdef CONFIG_X86_32
+#if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
extern int timer_ack;
+#else
+# define timer_ack (0)
#endif
-extern int recalibrate_cpu_khz(void);
extern int no_timer_check;
diff --git a/arch/x86/kernel/time_32.c b/arch/x86/kernel/time_32.c
index acbaefd61e8e..7a26bcf887f6 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 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
/* 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 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
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 45914f8844a7..35e0a925da56 100644
--- a/arch/x86/kernel/time_64.c
+++ b/arch/x86/kernel/time_64.c
@@ -51,6 +51,20 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
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