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 #ifdef CONFIG_X86_64
  29 __visible volatile unsigned long jiffies __cacheline_aligned_in_smp = INITIAL_JIFFIES;
  30 #endif
  31
  32 unsigned long profile_pc(struct pt_regs *regs)
  33 {
  34         unsigned long pc = instruction_pointer(regs);
  35
  36         if (!user_mode(regs) && in_lock_functions(pc)) {
  37 #ifdef CONFIG_FRAME_POINTER
  38                 return *(unsigned long *)(regs->bp + sizeof(long));
  39 #else
  40                 unsigned long *sp =
  41                         (unsigned long *)kernel_stack_pointer(regs);
  42                 /*
  43                  * Return address is either directly at stack pointer
  44                  * or above a saved flags. Eflags has bits 22-31 zero,
  45                  * kernel addresses don't.
  46                  */
  47                 if (sp[0] >> 22)
  48                         return sp[0];
  49                 if (sp[1] >> 22)
  50                         return sp[1];
  51 #endif
  52         }
  53         return pc;
  54 }
  55 EXPORT_SYMBOL(profile_pc);
  56
  57 /*
  58  * Default timer interrupt handler for PIT/HPET
  59  */
  60 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  61 {
  62         global_clock_event->event_handler(global_clock_event);
  63         return IRQ_HANDLED;
  64 }
  65
  66 static struct irqaction irq0  = {
  67         .handler = timer_interrupt,
  68         .flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
  69         .name = "timer"
  70 };
  71
  72 static void __init setup_default_timer_irq(void)
  73 {
  74         /*
  75          * Unconditionally register the legacy timer; even without legacy
  76          * PIC/PIT we need this for the HPET0 in legacy replacement mode.
  77          */
  78         if (setup_irq(0, &irq0))
  79                 pr_info("Failed to register legacy timer interrupt\n");
  80 }
  81
  82 /* Default timer init function */
  83 void __init hpet_time_init(void)
  84 {
  85         if (!hpet_enable())
  86                 setup_pit_timer();
  87         setup_default_timer_irq();
  88 }
  89
  90 static __init void x86_late_time_init(void)
  91 {
  92         x86_init.timers.timer_init();
  93         /*
  94          * After PIT/HPET timers init, select and setup
  95          * the final interrupt mode for delivering IRQs.
  96          */
  97         x86_init.irqs.intr_mode_init();
  98         tsc_init();
  99 }
 100
 101 /*
 102  * Initialize TSC and delay the periodic timer init to
 103  * late x86_late_time_init() so ioremap works.
 104  */
 105 void __init time_init(void)
 106 {
 107         late_time_init = x86_late_time_init;
 108 }
 109
 110 /*
 111  * Sanity check the vdso related archdata content.
 112  */
 113 void clocksource_arch_init(struct clocksource *cs)
 114 {
 115         if (cs->archdata.vclock_mode == VCLOCK_NONE)
 116                 return;
 117
 118         if (cs->archdata.vclock_mode > VCLOCK_MAX) {
 119                 pr_warn("clocksource %s registered with invalid vclock_mode %d. Disabling vclock.\n",
 120                         cs->name, cs->archdata.vclock_mode);
 121                 cs->archdata.vclock_mode = VCLOCK_NONE;
 122         }
 123
 124         if (cs->mask != CLOCKSOURCE_MASK(64)) {
 125                 pr_warn("clocksource %s registered with invalid mask %016llx. Disabling vclock.\n",
 126                         cs->name, cs->mask);
 127                 cs->archdata.vclock_mode = VCLOCK_NONE;
 128         }
 129 }