arch/x86/kernel/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
  28 unsigned long profile_pc(struct pt_regs *regs)
  29 {
  30         return instruction_pointer(regs);
  31 }
  32 EXPORT_SYMBOL(profile_pc);
  33
  34 /*
  35  * Default timer interrupt handler for PIT/HPET
  36  */
  37 static 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
  43 static 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 */
  57 void __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
  67 static __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  */
  93 void __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  */
 101 void 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 }