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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>
This commit is contained in:
Thomas Gleixner 2009-08-20 15:54:21 +02:00
parent dd3e6e8c6e
commit 64fcbac1f3
3 changed files with 23 additions and 6 deletions
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10
arch/x86/include/asm/timer.h
View File

@ -9,12 +9,14 @@
unsigned long long native_sched_clock(void);
unsigned long native_calibrate_tsc(void);
#ifdef CONFIG_X86_32
extern int timer_ack;
#endif
extern int recalibrate_cpu_khz(void);
#if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
extern int timer_ack;
#else
# define timer_ack (0)
#endif
extern int no_timer_check;
#ifndef CONFIG_PARAVIRT

5
arch/x86/kernel/time_32.c
View File

@ -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);

14
arch/x86/kernel/time_64.c
View File

@ -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