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 = (unsigned long *)regs->sp;
  41                 /*
  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.
  45                  */
  46                 if (sp[0] >> 22)
  47                         return sp[0];
  48                 if (sp[1] >> 22)
  49                         return sp[1];
  50 #endif
  51         }
  52         return pc;
  53 }
  54 EXPORT_SYMBOL(profile_pc);
  55
  56 /*
  57  * Default timer interrupt handler for PIT/HPET
  58  */
  59 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  60 {
  61         global_clock_event->event_handler(global_clock_event);
  62         return IRQ_HANDLED;
  63 }
  64
  65 static struct irqaction irq0  = {
  66         .handler = timer_interrupt,
  67         .flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
  68         .name = "timer"
  69 };
  70
  71 static void __init setup_default_timer_irq(void)
  72 {
  73         /*
  74          * Unconditionally register the legacy timer; even without legacy
  75          * PIC/PIT we need this for the HPET0 in legacy replacement mode.
  76          */
  77         if (setup_irq(0, &irq0))
  78                 pr_info("Failed to register legacy timer interrupt\n");
  79 }
  80
  81 /* Default timer init function */
  82 void __init hpet_time_init(void)
  83 {
  84         if (!hpet_enable()) {
  85                 if (!pit_timer_init())
  86                         return;
  87         }
  88
  89         setup_default_timer_irq();
  90 }
  91
  92 static __init void x86_late_time_init(void)
  93 {
  94         /*
  95          * Before PIT/HPET init, select the interrupt mode. This is required
  96          * to make the decision whether PIT should be initialized correct.
  97          */
  98         x86_init.irqs.intr_mode_select();
  99
 100         /* Setup the legacy timers */
 101         x86_init.timers.timer_init();
 102
 103         /*
 104          * After PIT/HPET timers init, set up the final interrupt mode for
 105          * delivering IRQs.
 106          */
 107         x86_init.irqs.intr_mode_init();
 108         tsc_init();
 109 }
 110
 111 /*
 112  * Initialize TSC and delay the periodic timer init to
 113  * late x86_late_time_init() so ioremap works.
 114  */
 115 void __init time_init(void)
 116 {
 117         late_time_init = x86_late_time_init;
 118 }
 119
 120 /*
 121  * Sanity check the vdso related archdata content.
 122  */
 123 void clocksource_arch_init(struct clocksource *cs)
 124 {
 125         if (cs->archdata.vclock_mode == VCLOCK_NONE)
 126                 return;
 127
 128         if (cs->archdata.vclock_mode > VCLOCK_MAX) {
 129                 pr_warn("clocksource %s registered with invalid vclock_mode %d. Disabling vclock.\n",
 130                         cs->name, cs->archdata.vclock_mode);
 131                 cs->archdata.vclock_mode = VCLOCK_NONE;
 132         }
 133
 134         if (cs->mask != CLOCKSOURCE_MASK(64)) {
 135                 pr_warn("clocksource %s registered with invalid mask %016llx. Disabling vclock.\n",
 136                         cs->name, cs->mask);
 137                 cs->archdata.vclock_mode = VCLOCK_NONE;
 138         }
 139 }