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/arch/x86/kernel/time.c

https://bitbucket.org/ndreys/linux-sunxi
C | 103 lines | 64 code | 14 blank | 25 comment | 6 complexity | d5528212de8db0ae4da20cc11cc7962b MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  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#ifdef CONFIG_X86_64
 26DEFINE_VVAR(volatile unsigned long, jiffies) = 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_vm(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	/* Keep nmi watchdog up to date */
 60	inc_irq_stat(irq0_irqs);
 61
 62	global_clock_event->event_handler(global_clock_event);
 63
 64	/* MCA bus quirk: Acknowledge irq0 by setting bit 7 in port 0x61 */
 65	if (MCA_bus)
 66		outb_p(inb_p(0x61)| 0x80, 0x61);
 67
 68	return IRQ_HANDLED;
 69}
 70
 71static struct irqaction irq0  = {
 72	.handler = timer_interrupt,
 73	.flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
 74	.name = "timer"
 75};
 76
 77void __init setup_default_timer_irq(void)
 78{
 79	setup_irq(0, &irq0);
 80}
 81
 82/* Default timer init function */
 83void __init hpet_time_init(void)
 84{
 85	if (!hpet_enable())
 86		setup_pit_timer();
 87	setup_default_timer_irq();
 88}
 89
 90static __init void x86_late_time_init(void)
 91{
 92	x86_init.timers.timer_init();
 93	tsc_init();
 94}
 95
 96/*
 97 * Initialize TSC and delay the periodic timer init to
 98 * late x86_late_time_init() so ioremap works.
 99 */
100void __init time_init(void)
101{
102	late_time_init = x86_late_time_init;
103}