The x86 timer interrupt handler is the only handler not traced in the
[linux-2.6/next.git] / arch / x86 / kernel / time.c
blob25046df137f24653e810ed63220482106a965ad4
1 /*
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/i8253.h>
15 #include <linux/time.h>
16 #include <linux/export.h>
17 #include <linux/mca.h>
19 #include <asm/vsyscall.h>
20 #include <asm/x86_init.h>
21 #include <asm/i8259.h>
22 #include <asm/timer.h>
23 #include <asm/hpet.h>
24 #include <asm/time.h>
26 #ifdef CONFIG_X86_64
27 DEFINE_VVAR(volatile unsigned long, jiffies) = INITIAL_JIFFIES;
28 #endif
30 unsigned long profile_pc(struct pt_regs *regs)
32 unsigned long pc = instruction_pointer(regs);
34 if (!user_mode_vm(regs) && in_lock_functions(pc)) {
35 #ifdef CONFIG_FRAME_POINTER
36 return *(unsigned long *)(regs->bp + sizeof(long));
37 #else
38 unsigned long *sp =
39 (unsigned long *)kernel_stack_pointer(regs);
41 * Return address is either directly at stack pointer
42 * or above a saved flags. Eflags has bits 22-31 zero,
43 * kernel addresses don't.
45 if (sp[0] >> 22)
46 return sp[0];
47 if (sp[1] >> 22)
48 return sp[1];
49 #endif
51 return pc;
53 EXPORT_SYMBOL(profile_pc);
55 static irqreturn_t timer_interrupt(int irq, void *dev_id);
56 static struct irqaction irq0 = {
57 .handler = timer_interrupt,
58 .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
59 .name = "timer"
63 * Default timer interrupt handler for PIT/HPET
65 static irqreturn_t timer_interrupt(int irq, void *dev_id)
67 /* Keep nmi watchdog up to date */
68 inc_irq_stat(irq0_irqs);
70 trace_irq_handler_entry(irq, &irq0);
71 global_clock_event->event_handler(global_clock_event);
72 trace_irq_handler_exit(irq, &irq0, 1);
74 /* MCA bus quirk: Acknowledge irq0 by setting bit 7 in port 0x61 */
75 if (MCA_bus)
76 outb_p(inb_p(0x61)| 0x80, 0x61);
78 return IRQ_HANDLED;
81 void __init setup_default_timer_irq(void)
83 setup_irq(0, &irq0);
86 /* Default timer init function */
87 void __init hpet_time_init(void)
89 if (!hpet_enable())
90 setup_pit_timer();
91 setup_default_timer_irq();
94 static __init void x86_late_time_init(void)
96 x86_init.timers.timer_init();
97 tsc_init();
101 * Initialize TSC and delay the periodic timer init to
102 * late x86_late_time_init() so ioremap works.
104 void __init time_init(void)
106 late_time_init = x86_late_time_init;