2 * Copyright (c) 1991,1992,1995 Linus Torvalds
3 * Copyright (c) 1994 Alan Modra
4 * Copyright (c) 1995 Markus Kuhn
5 * Copyright (c) 1996 Ingo Molnar
6 * Copyright (c) 1998 Andrea Arcangeli
7 * Copyright (c) 2002,2006 Vojtech Pavlik
8 * Copyright (c) 2003 Andi Kleen
12 #include <linux/clockchips.h>
13 #include <linux/interrupt.h>
14 #include <linux/time.h>
15 #include <linux/mca.h>
17 #include <asm/vsyscall.h>
18 #include <asm/x86_init.h>
19 #include <asm/i8259.h>
20 #include <asm/i8253.h>
21 #include <asm/timer.h>
25 #if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
30 volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
33 unsigned long profile_pc(struct pt_regs *regs)
35 unsigned long pc = instruction_pointer(regs);
37 if (!user_mode_vm(regs) && in_lock_functions(pc)) {
38 #ifdef CONFIG_FRAME_POINTER
39 return *(unsigned long *)(regs->bp + sizeof(long));
42 (unsigned long *)kernel_stack_pointer(regs);
44 * Return address is either directly at stack pointer
45 * or above a saved flags. Eflags has bits 22-31 zero,
46 * kernel addresses don't.
56 EXPORT_SYMBOL(profile_pc);
59 * Default timer interrupt handler for PIT/HPET
61 static irqreturn_t timer_interrupt(int irq, void *dev_id)
63 /* Keep nmi watchdog up to date */
64 inc_irq_stat(irq0_irqs);
66 /* Optimized out for !IO_APIC and x86_64 */
69 * Subtle, when I/O APICs are used we have to ack timer IRQ
70 * manually to deassert NMI lines for the watchdog if run
71 * on an 82489DX-based system.
73 spin_lock(&i8259A_lock);
74 outb(0x0c, PIC_MASTER_OCW3);
75 /* Ack the IRQ; AEOI will end it automatically. */
77 spin_unlock(&i8259A_lock);
80 global_clock_event->event_handler(global_clock_event);
82 /* MCA bus quirk: Acknowledge irq0 by setting bit 7 in port 0x61 */
84 outb_p(inb_p(0x61)| 0x80, 0x61);
89 static struct irqaction irq0 = {
90 .handler = timer_interrupt,
91 .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
95 void __init setup_default_timer_irq(void)
100 /* Default timer init function */
101 void __init hpet_time_init(void)
105 setup_default_timer_irq();
108 static __init void x86_late_time_init(void)
110 x86_init.timers.timer_init();
115 * Initialize TSC and delay the periodic timer init to
116 * late x86_late_time_init() so ioremap works.
118 void __init time_init(void)
120 late_time_init = x86_late_time_init;