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/include/asm/timer.h b/arch/x86/include/asm/timer.h
index e854c7a..65228cc 100644 (file)
--- 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 acbaefd..7a26bcf 100644 (file)
--- 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 45914f8..35e0a92 100644 (file)
--- 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