time.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  Copyright (c) 1991,1992,1995  Linus Torvalds
  4 *  Copyright (c) 1994  Alan Modra
  5 *  Copyright (c) 1995  Markus Kuhn
  6 *  Copyright (c) 1996  Ingo Molnar
  7 *  Copyright (c) 1998  Andrea Arcangeli
  8 *  Copyright (c) 2002,2006  Vojtech Pavlik
  9 *  Copyright (c) 2003  Andi Kleen
 10 *
 11 */
 12
 13#include <linux/clocksource.h>
 14#include <linux/clockchips.h>
 15#include <linux/interrupt.h>
 16#include <linux/irq.h>
 17#include <linux/i8253.h>
 18#include <linux/time.h>
 19#include <linux/export.h>
 20
 21#include <asm/vsyscall.h>
 22#include <asm/x86_init.h>
 23#include <asm/i8259.h>
 24#include <asm/timer.h>
 25#include <asm/hpet.h>
 26#include <asm/time.h>
 27
 28unsigned long profile_pc(struct pt_regs *regs)
 29{
 30	return instruction_pointer(regs);
 31}
 32EXPORT_SYMBOL(profile_pc);
 33
 34/*
 35 * Default timer interrupt handler for PIT/HPET
 36 */
 37static irqreturn_t timer_interrupt(int irq, void *dev_id)
 38{
 39	global_clock_event->event_handler(global_clock_event);
 40	return IRQ_HANDLED;
 41}
 42
 43static void __init setup_default_timer_irq(void)
 44{
 45	unsigned long flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER;
 46
 47	/*
 48	 * Unconditionally register the legacy timer interrupt; even
 49	 * without legacy PIC/PIT we need this for the HPET0 in legacy
 50	 * replacement mode.
 51	 */
 52	if (request_irq(0, timer_interrupt, flags, "timer", NULL))
 53		pr_info("Failed to register legacy timer interrupt\n");
 54}
 55
 56/* Default timer init function */
 57void __init hpet_time_init(void)
 58{
 59	if (!hpet_enable()) {
 60		if (!pit_timer_init())
 61			return;
 62	}
 63
 64	setup_default_timer_irq();
 65}
 66
 67static __init void x86_late_time_init(void)
 68{
 69	/*
 70	 * Before PIT/HPET init, select the interrupt mode. This is required
 71	 * to make the decision whether PIT should be initialized correct.
 72	 */
 73	x86_init.irqs.intr_mode_select();
 74
 75	/* Setup the legacy timers */
 76	x86_init.timers.timer_init();
 77
 78	/*
 79	 * After PIT/HPET timers init, set up the final interrupt mode for
 80	 * delivering IRQs.
 81	 */
 82	x86_init.irqs.intr_mode_init();
 83	tsc_init();
 84
 85	if (static_cpu_has(X86_FEATURE_WAITPKG))
 86		use_tpause_delay();
 87}
 88
 89/*
 90 * Initialize TSC and delay the periodic timer init to
 91 * late x86_late_time_init() so ioremap works.
 92 */
 93void __init time_init(void)
 94{
 95	late_time_init = x86_late_time_init;
 96}
 97
 98/*
 99 * Sanity check the vdso related archdata content.
100 */
101void clocksource_arch_init(struct clocksource *cs)
102{
103	if (cs->vdso_clock_mode == VDSO_CLOCKMODE_NONE)
104		return;
105
106	if (cs->mask != CLOCKSOURCE_MASK(64)) {
107		pr_warn("clocksource %s registered with invalid mask %016llx for VDSO. Disabling VDSO support.\n",
108			cs->name, cs->mask);
109		cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;
110	}
111}