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>
26 #if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
31 volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
34 unsigned long profile_pc(struct pt_regs *regs)
36 unsigned long pc = instruction_pointer(regs);
39 if (!user_mode_vm(regs) && in_lock_functions(pc)) {
40 #ifdef CONFIG_FRAME_POINTER
41 return *(unsigned long *)(regs->bp + sizeof(long));
43 unsigned long *sp = (unsigned long *)®s->sp;
45 /* Return address is either directly at stack pointer
46 or above a saved flags. Eflags has bits 22-31 zero,
47 kernel addresses don't. */
57 EXPORT_SYMBOL(profile_pc);
60 * Default timer interrupt handler for PIT/HPET
62 static irqreturn_t timer_interrupt(int irq, void *dev_id)
64 /* Keep nmi watchdog up to date */
65 inc_irq_stat(irq0_irqs);
67 /* Optimized out for !IO_APIC and x86_64 */
70 * Subtle, when I/O APICs are used we have to ack timer IRQ
71 * manually to deassert NMI lines for the watchdog if run
72 * on an 82489DX-based system.
74 spin_lock(&i8259A_lock);
75 outb(0x0c, PIC_MASTER_OCW3);
76 /* Ack the IRQ; AEOI will end it automatically. */
78 spin_unlock(&i8259A_lock);
81 global_clock_event->event_handler(global_clock_event);
83 /* MCA bus quirk: Acknowledge irq0 by setting bit 7 in port 0x61 */
85 outb_p(inb_p(0x61)| 0x80, 0x61);
90 static struct irqaction irq0 = {
91 .handler = timer_interrupt,
92 .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
96 void __init setup_default_timer_irq(void)
98 irq0.mask = cpumask_of_cpu(0);
102 /* Default timer init function */
103 void __init hpet_time_init(void)
107 setup_default_timer_irq();
110 static void x86_late_time_init(void)
112 x86_init.timers.timer_init();
116 * Initialize TSC and delay the periodic timer init to
117 * late x86_late_time_init() so ioremap works.
119 void __init time_init(void)
122 late_time_init = x86_late_time_init;