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
profile_pc(struct pt_regs * regs)28 unsigned long profile_pc(struct pt_regs *regs)
29 {
30 unsigned long pc = instruction_pointer(regs);
31
32 if (!user_mode(regs) && in_lock_functions(pc)) {
33 #ifdef CONFIG_FRAME_POINTER
34 return *(unsigned long *)(regs->bp + sizeof(long));
35 #else
36 unsigned long *sp = (unsigned long *)regs->sp;
37 /*
38 * Return address is either directly at stack pointer
39 * or above a saved flags. Eflags has bits 22-31 zero,
40 * kernel addresses don't.
41 */
42 if (sp[0] >> 22)
43 return sp[0];
44 if (sp[1] >> 22)
45 return sp[1];
46 #endif
47 }
48 return pc;
49 }
50 EXPORT_SYMBOL(profile_pc);
51
52 /*
53 * Default timer interrupt handler for PIT/HPET
54 */
timer_interrupt(int irq,void * dev_id)55 static irqreturn_t timer_interrupt(int irq, void *dev_id)
56 {
57 global_clock_event->event_handler(global_clock_event);
58 return IRQ_HANDLED;
59 }
60
61 static struct irqaction irq0 = {
62 .handler = timer_interrupt,
63 .flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
64 .name = "timer"
65 };
66
setup_default_timer_irq(void)67 static void __init setup_default_timer_irq(void)
68 {
69 /*
70 * Unconditionally register the legacy timer; even without legacy
71 * PIC/PIT we need this for the HPET0 in legacy replacement mode.
72 */
73 if (setup_irq(0, &irq0))
74 pr_info("Failed to register legacy timer interrupt\n");
75 }
76
77 /* Default timer init function */
hpet_time_init(void)78 void __init hpet_time_init(void)
79 {
80 if (!hpet_enable()) {
81 if (!pit_timer_init())
82 return;
83 }
84
85 setup_default_timer_irq();
86 }
87
x86_late_time_init(void)88 static __init void x86_late_time_init(void)
89 {
90 /*
91 * Before PIT/HPET init, select the interrupt mode. This is required
92 * to make the decision whether PIT should be initialized correct.
93 */
94 x86_init.irqs.intr_mode_select();
95
96 /* Setup the legacy timers */
97 x86_init.timers.timer_init();
98
99 /*
100 * After PIT/HPET timers init, set up the final interrupt mode for
101 * delivering IRQs.
102 */
103 x86_init.irqs.intr_mode_init();
104 tsc_init();
105 }
106
107 /*
108 * Initialize TSC and delay the periodic timer init to
109 * late x86_late_time_init() so ioremap works.
110 */
time_init(void)111 void __init time_init(void)
112 {
113 late_time_init = x86_late_time_init;
114 }
115
116 /*
117 * Sanity check the vdso related archdata content.
118 */
clocksource_arch_init(struct clocksource * cs)119 void clocksource_arch_init(struct clocksource *cs)
120 {
121 if (cs->archdata.vclock_mode == VCLOCK_NONE)
122 return;
123
124 if (cs->archdata.vclock_mode > VCLOCK_MAX) {
125 pr_warn("clocksource %s registered with invalid vclock_mode %d. Disabling vclock.\n",
126 cs->name, cs->archdata.vclock_mode);
127 cs->archdata.vclock_mode = VCLOCK_NONE;
128 }
129
130 if (cs->mask != CLOCKSOURCE_MASK(64)) {
131 pr_warn("clocksource %s registered with invalid mask %016llx. Disabling vclock.\n",
132 cs->name, cs->mask);
133 cs->archdata.vclock_mode = VCLOCK_NONE;
134 }
135 }
136