time.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 1991,1992,1995 Linus Torvalds
* Copyright (c) 1994 Alan Modra
* Copyright (c) 1995 Markus Kuhn
* Copyright (c) 1996 Ingo Molnar
* Copyright (c) 1998 Andrea Arcangeli
* Copyright (c) 2002,2006 Vojtech Pavlik
* Copyright (c) 2003 Andi Kleen
*
*/
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/i8253.h>
#include <linux/time.h>
#include <linux/export.h>
#include <asm/vsyscall.h>
#include <asm/x86_init.h>
#include <asm/i8259.h>
#include <asm/timer.h>
#include <asm/hpet.h>
#include <asm/time.h>
unsigned long profile_pc(struct pt_regs *regs)
{
unsigned long pc = instruction_pointer(regs);
if (!user_mode(regs) && in_lock_functions(pc)) {
#ifdef CONFIG_FRAME_POINTER
return *(unsigned long *)(regs->bp + sizeof(long));
#else
unsigned long *sp = (unsigned long *)regs->sp;
/*
* Return address is either directly at stack pointer
* or above a saved flags. Eflags has bits 22-31 zero,
* kernel addresses don't.
*/
if (sp[0] >> 22)
return sp[0];
if (sp[1] >> 22)
return sp[1];
#endif
}
return pc;
}
EXPORT_SYMBOL(profile_pc);
/*
* Default timer interrupt handler for PIT/HPET
*/
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
global_clock_event->event_handler(global_clock_event);
return IRQ_HANDLED;
}
static void __init setup_default_timer_irq(void)
{
unsigned long flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER;
/*
* Unconditionally register the legacy timer interrupt; even
* without legacy PIC/PIT we need this for the HPET0 in legacy
* replacement mode.
*/
if (request_irq(0, timer_interrupt, flags, "timer", NULL))
pr_info("Failed to register legacy timer interrupt\n");
}
/* Default timer init function */
void __init hpet_time_init(void)
{
if (!hpet_enable()) {
if (!pit_timer_init())
return;
}
setup_default_timer_irq();
}
static __init void x86_late_time_init(void)
{
/*
* Before PIT/HPET init, select the interrupt mode. This is required
* to make the decision whether PIT should be initialized correct.
*/
x86_init.irqs.intr_mode_select();
/* Setup the legacy timers */
x86_init.timers.timer_init();
/*
* After PIT/HPET timers init, set up the final interrupt mode for
* delivering IRQs.
*/
x86_init.irqs.intr_mode_init();
tsc_init();
if (static_cpu_has(X86_FEATURE_WAITPKG))
use_tpause_delay();
}
/*
* Initialize TSC and delay the periodic timer init to
* late x86_late_time_init() so ioremap works.
*/
void __init time_init(void)
{
late_time_init = x86_late_time_init;
}
/*
* Sanity check the vdso related archdata content.
*/
void clocksource_arch_init(struct clocksource *cs)
{
if (cs->vdso_clock_mode == VDSO_CLOCKMODE_NONE)
return;
if (cs->mask != CLOCKSOURCE_MASK(64)) {
pr_warn("clocksource %s registered with invalid mask %016llx for VDSO. Disabling VDSO support.\n",
cs->name, cs->mask);
cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;
}
}