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/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> 19 20 #include <asm/vsyscall.h> 21 #include <asm/x86_init.h> 22 #include <asm/i8259.h> 23 #include <asm/timer.h> 24 #include <asm/hpet.h> 25 #include <asm/time.h> 26 27 #ifdef CONFIG_X86_64 28 __visible volatile unsigned long jiffies __cacheline_aligned = INITIAL_JIFFIES; 29 #endif 30 31 unsigned long profile_pc(struct pt_regs *regs) 32 { 33 unsigned long pc = instruction_pointer(regs); 34 35 if (!user_mode(regs) && in_lock_functions(pc)) { 36 #ifdef CONFIG_FRAME_POINTER 37 return *(unsigned long *)(regs->bp + sizeof(long)); 38 #else 39 unsigned long *sp = 40 (unsigned long *)kernel_stack_pointer(regs); 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 setup_pit_timer(); 86 setup_default_timer_irq(); 87 } 88 89 static __init void x86_late_time_init(void) 90 { 91 x86_init.timers.timer_init(); 92 /* 93 * After PIT/HPET timers init, select and setup 94 * the final interrupt mode for delivering IRQs. 95 */ 96 x86_init.irqs.intr_mode_init(); 97 tsc_init(); 98 } 99 100 /* 101 * Initialize TSC and delay the periodic timer init to 102 * late x86_late_time_init() so ioremap works. 103 */ 104 void __init time_init(void) 105 { 106 late_time_init = x86_late_time_init; 107 } 108