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/*
* "High Precision Event Timer" based timekeeping.
*
* Copyright (c) 1991,1992,1995 Linus Torvalds
* Copyright (c) 1994 Alan Modra
* Copyright (c) 1995 Markus Kuhn
* Copyright (c) 1996 Ingo Molnar
* Copyright (c) 1998 Andrea Arcangeli
* Copyright (c) 2002,2006 Vojtech Pavlik
* Copyright (c) 2003 Andi Kleen
* RTC support code taken from arch/i386/kernel/timers/time_hpet.c
*/
#include <linux/clockchips.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/time.h>
#include <asm/i8253.h>
#include <asm/hpet.h>
#include <asm/nmi.h>
#include <asm/vgtod.h>
volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
unsigned long profile_pc(struct pt_regs *regs)
{
unsigned long pc = instruction_pointer(regs);
/* Assume the lock function has either no stack frame or a copy
of eflags from PUSHF
Eflags always has bits 22 and up cleared unlike kernel addresses. */
if (!user_mode(regs) && in_lock_functions(pc)) {
unsigned long *sp = (unsigned long *)regs->rsp;
if (sp[0] >> 22)
return sp[0];
if (sp[1] >> 22)
return sp[1];
}
return pc;
}
EXPORT_SYMBOL(profile_pc);
static irqreturn_t timer_event_interrupt(int irq, void *dev_id)
{
add_pda(irq0_irqs, 1);
global_clock_event->event_handler(global_clock_event);
return IRQ_HANDLED;
}
/* calibrate_cpu is used on systems with fixed rate TSCs to determine
* processor frequency */
#define TICK_COUNT 100000000
static unsigned int __init tsc_calibrate_cpu_khz(void)
{
int tsc_start, tsc_now;
int i, no_ctr_free;
unsigned long evntsel3 = 0, pmc3 = 0, pmc_now = 0;
unsigned long flags;
for (i = 0; i < 4; i++)
if (avail_to_resrv_perfctr_nmi_bit(i))
break;
no_ctr_free = (i == 4);
if (no_ctr_free) {
i = 3;
rdmsrl(MSR_K7_EVNTSEL3, evntsel3);
wrmsrl(MSR_K7_EVNTSEL3, 0);
rdmsrl(MSR_K7_PERFCTR3, pmc3);
} else {
reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i);
reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
}
local_irq_save(flags);
/* start meauring cycles, incrementing from 0 */
wrmsrl(MSR_K7_PERFCTR0 + i, 0);
wrmsrl(MSR_K7_EVNTSEL0 + i, 1 << 22 | 3 << 16 | 0x76);
rdtscl(tsc_start);
do {
rdmsrl(MSR_K7_PERFCTR0 + i, pmc_now);
tsc_now = get_cycles_sync();
} while ((tsc_now - tsc_start) < TICK_COUNT);
local_irq_restore(flags);
if (no_ctr_free) {
wrmsrl(MSR_K7_EVNTSEL3, 0);
wrmsrl(MSR_K7_PERFCTR3, pmc3);
wrmsrl(MSR_K7_EVNTSEL3, evntsel3);
} else {
release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
release_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
}
return pmc_now * tsc_khz / (tsc_now - tsc_start);
}
static struct irqaction irq0 = {
.handler = timer_event_interrupt,
.flags = IRQF_DISABLED | IRQF_IRQPOLL | IRQF_NOBALANCING,
.mask = CPU_MASK_NONE,
.name = "timer"
};
void __init time_init(void)
{
if (!hpet_enable())
setup_pit_timer();
setup_irq(0, &irq0);
tsc_calibrate();
cpu_khz = tsc_khz;
if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) &&
boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
boot_cpu_data.x86 == 16)
cpu_khz = tsc_calibrate_cpu_khz();
if (unsynchronized_tsc())
mark_tsc_unstable("TSCs unsynchronized");
if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
vgetcpu_mode = VGETCPU_RDTSCP;
else
vgetcpu_mode = VGETCPU_LSL;
printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n",
cpu_khz / 1000, cpu_khz % 1000);
init_tsc_clocksource();
}
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