release/src-rt-6.x.4708/linux/linux-2.6.36/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/time.h>
  15 #include <linux/mca.h>
  16
  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>
  22 #include <asm/hpet.h>
  23 #include <asm/time.h>
  24
  25 #if defined(CONFIG_X86_32) && defined(CONFIG_X86_IO_APIC)
  26 int timer_ack;
  27 #endif
  28
  29 #ifdef CONFIG_X86_64
  30 volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
  31 #endif
  32
  33 unsigned long profile_pc(struct pt_regs *regs)
  34 {
  35         unsigned long pc = instruction_pointer(regs);
  36
  37         if (!user_mode_vm(regs) && in_lock_functions(pc)) {
  38 #ifdef CONFIG_FRAME_POINTER
  39                 return *(unsigned long *)(regs->bp + sizeof(long));
  40 #else
  41                 unsigned long *sp =
  42                         (unsigned long *)kernel_stack_pointer(regs);
  43                 /*
  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.
  47                  */
  48                 if (sp[0] >> 22)
  49                         return sp[0];
  50                 if (sp[1] >> 22)
  51                         return sp[1];
  52 #endif
  53         }
  54         return pc;
  55 }
  56 EXPORT_SYMBOL(profile_pc);
  57
  58 /*
  59  * Default timer interrupt handler for PIT/HPET
  60  */
  61 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  62 {
  63         /* Keep nmi watchdog up to date */
  64         inc_irq_stat(irq0_irqs);
  65
  66         /* Optimized out for !IO_APIC and x86_64 */
  67         if (timer_ack) {
  68                 /*
  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.
  72                  */
  73                 raw_spin_lock(&i8259A_lock);
  74                 outb(0x0c, PIC_MASTER_OCW3);
  75                 /* Ack the IRQ; AEOI will end it automatically. */
  76                 inb(PIC_MASTER_POLL);
  77                 raw_spin_unlock(&i8259A_lock);
  78         }
  79
  80         global_clock_event->event_handler(global_clock_event);
  81
  82         /* MCA bus quirk: Acknowledge irq0 by setting bit 7 in port 0x61 */
  83         if (MCA_bus)
  84                 outb_p(inb_p(0x61)| 0x80, 0x61);
  85
  86         return IRQ_HANDLED;
  87 }
  88
  89 static struct irqaction irq0  = {
  90         .handler = timer_interrupt,
  91         .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
  92         .name = "timer"
  93 };
  94
  95 void __init setup_default_timer_irq(void)
  96 {
  97         setup_irq(0, &irq0);
  98 }
  99
 100 /* Default timer init function */
 101 void __init hpet_time_init(void)
 102 {
 103         if (!hpet_enable())
 104                 setup_pit_timer();
 105         setup_default_timer_irq();
 106 }
 107
 108 static __init void x86_late_time_init(void)
 109 {
 110         x86_init.timers.timer_init();
 111         tsc_init();
 112 }
 113
 114 /*
 115  * Initialize TSC and delay the periodic timer init to
 116  * late x86_late_time_init() so ioremap works.
 117  */
 118 void __init time_init(void)
 119 {
 120         late_time_init = x86_late_time_init;
 121 }