1 // SPDX-License-Identifier: GPL-2.0
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
13 #include <linux/clockchips.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/i8253.h>
17 #include <linux/time.h>
18 #include <linux/export.h>
20 #include <asm/vsyscall.h>
21 #include <asm/x86_init.h>
22 #include <asm/i8259.h>
23 #include <asm/timer.h>
28 __visible volatile unsigned long jiffies __cacheline_aligned_in_smp = INITIAL_JIFFIES;
31 unsigned long profile_pc(struct pt_regs *regs)
33 unsigned long pc = instruction_pointer(regs);
35 if (!user_mode(regs) && in_lock_functions(pc)) {
36 #ifdef CONFIG_FRAME_POINTER
37 return *(unsigned long *)(regs->bp + sizeof(long));
40 (unsigned long *)kernel_stack_pointer(regs);
42 * Return address is either directly at stack pointer
43 * or above a saved flags. Eflags has bits 22-31 zero,
44 * kernel addresses don't.
54 EXPORT_SYMBOL(profile_pc);
57 * Default timer interrupt handler for PIT/HPET
59 static irqreturn_t timer_interrupt(int irq, void *dev_id)
61 global_clock_event->event_handler(global_clock_event);
65 static struct irqaction irq0 = {
66 .handler = timer_interrupt,
67 .flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
71 static void __init setup_default_timer_irq(void)
74 * Unconditionally register the legacy timer; even without legacy
75 * PIC/PIT we need this for the HPET0 in legacy replacement mode.
77 if (setup_irq(0, &irq0))
78 pr_info("Failed to register legacy timer interrupt\n");
81 /* Default timer init function */
82 void __init hpet_time_init(void)
86 setup_default_timer_irq();
89 static __init void x86_late_time_init(void)
91 x86_init.timers.timer_init();
93 * After PIT/HPET timers init, select and setup
94 * the final interrupt mode for delivering IRQs.
96 x86_init.irqs.intr_mode_init();
101 * Initialize TSC and delay the periodic timer init to
102 * late x86_late_time_init() so ioremap works.
104 void __init time_init(void)
106 late_time_init = x86_late_time_init;