LXR linux/arch/x86/kernel/time.c

   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
   9 *
  10 */
  11
  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
  18#include <asm/vsyscall.h>
  19#include <asm/x86_init.h>
  20#include <asm/i8259.h>
  21#include <asm/timer.h>
  22#include <asm/hpet.h>
  23#include <asm/time.h>
  24
  25#ifdef CONFIG_X86_64
  26__visible volatile unsigned long jiffies __cacheline_aligned = INITIAL_JIFFIES;
  27#endif
  28
  29unsigned long profile_pc(struct pt_regs *regs)
  30{
  31        unsigned long pc = instruction_pointer(regs);
  32
  33        if (!user_mode(regs) && in_lock_functions(pc)) {
  34#ifdef CONFIG_FRAME_POINTER
  35                return *(unsigned long *)(regs->bp + sizeof(long));
  36#else
  37                unsigned long *sp =
  38                        (unsigned long *)kernel_stack_pointer(regs);
  39                /*
  40                 * Return address is either directly at stack pointer
  41                 * or above a saved flags. Eflags has bits 22-31 zero,
  42                 * kernel addresses don't.
  43                 */
  44                if (sp[0] >> 22)
  45                        return sp[0];
  46                if (sp[1] >> 22)
  47                        return sp[1];
  48#endif
  49        }
  50        return pc;
  51}
  52EXPORT_SYMBOL(profile_pc);
  53
  54/*
  55 * Default timer interrupt handler for PIT/HPET
  56 */
  57static irqreturn_t timer_interrupt(int irq, void *dev_id)
  58{
  59        global_clock_event->event_handler(global_clock_event);
  60        return IRQ_HANDLED;
  61}
  62
  63static struct irqaction irq0  = {
  64        .handler = timer_interrupt,
  65        .flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
  66        .name = "timer"
  67};
  68
  69void __init setup_default_timer_irq(void)
  70{
  71        if (!nr_legacy_irqs())
  72                return;
  73        setup_irq(0, &irq0);
  74}
  75
  76/* Default timer init function */
  77void __init hpet_time_init(void)
  78{
  79        if (!hpet_enable())
  80                setup_pit_timer();
  81        setup_default_timer_irq();
  82}
  83
  84static __init void x86_late_time_init(void)
  85{
  86        x86_init.timers.timer_init();
  87        tsc_init();
  88}
  89
  90/*
  91 * Initialize TSC and delay the periodic timer init to
  92 * late x86_late_time_init() so ioremap works.
  93 */
  94void __init time_init(void)
  95{
  96        late_time_init = x86_late_time_init;
  97}
  98