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x86: fix debug message of CPU clock speed 

Impact: Fixes incorrect printk

LOCAL APIC is corrected by PM-Timer, when SMI occurred while LOCAL APIC is calibrated.
In this case, LOCAL APIC debug message(Boot with apic=debug) is displayed correctly,
however, CPU clock speed debug message is displayed wrongly .

When SMI occured on my machine, which has 1.6GHz CPU, CPU clock speed is displayed
3622.0205 MHz as follow.

	CPU0: Intel(R) Xeon(R) CPU            5110  @ 1.60GHz stepping 06
	Using local APIC timer interrupts.
	calibrating APIC timer ...
	... lapic delta = 3773130
	... PM timer delta = 812434
	APIC calibration not consistent with PM Timer: 226ms instead of 100ms
	APIC delta adjusted to PM-Timer: 1662420 (3773130)
	..... delta 1662420
	..... mult: 71411249
	..... calibration result: 265987
	..... CPU clock speed is 3622.0205 MHz.  =====>  here
	..... host bus clock speed is 265.0987 MHz.

This patch fixes to displaying CPU clock speed correctly as follow.

	CPU0: Intel(R) Xeon(R) CPU            5110  @ 1.60GHz stepping 06
	Using local APIC timer interrupts.
	calibrating APIC timer ...
	... lapic delta = 3773131
	... PM timer delta = 812434
	APIC calibration not consistent with PM Timer: 226ms instead of 100ms
	APIC delta adjusted to PM-Timer: 1662420 (3773131)
	TSC delta adjusted to PM-Timer: 159592409 (362220564)
	..... delta 1662420
	..... mult: 71411249
	..... calibration result: 265987
	..... CPU clock speed is 1595.0924 MHz.
	..... host bus clock speed is 265.0987 MHz.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
hifive-unleashed-5.1
Yasuaki Ishimatsu 2009-01-28 12:51:09 +09:00 committed by H. Peter Anvin
parent 5ee8100721
commit 754ef0cd65
1 changed files with 30 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
arch/x86/kernel/apic.c
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@ -535,7 +535,8 @@ static void __init lapic_cal_handler(struct clock_event_device *dev)
}
}
static int __init calibrate_by_pmtimer(long deltapm, long *delta)
static int __init
calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
{
const long pm_100ms = PMTMR_TICKS_PER_SEC / 10;
const long pm_thresh = pm_100ms / 100;
@ -557,18 +558,29 @@ static int __init calibrate_by_pmtimer(long deltapm, long *delta)
if (deltapm > (pm_100ms - pm_thresh) &&
deltapm < (pm_100ms + pm_thresh)) {
apic_printk(APIC_VERBOSE, "... PM timer result ok\n");
} else {
res = (((u64)deltapm) * mult) >> 22;
do_div(res, 1000000);
pr_warning("APIC calibration not consistent "
"with PM Timer: %ldms instead of 100ms\n",
(long)res);
/* Correct the lapic counter value */
res = (((u64)(*delta)) * pm_100ms);
return 0;
}
res = (((u64)deltapm) * mult) >> 22;
do_div(res, 1000000);
pr_warning("APIC calibration not consistent "
"with PM Timer: %ldms instead of 100ms\n",(long)res);
/* Correct the lapic counter value */
res = (((u64)(*delta)) * pm_100ms);
do_div(res, deltapm);
pr_info("APIC delta adjusted to PM-Timer: "
"%lu (%ld)\n", (unsigned long)res, *delta);
*delta = (long)res;
/* Correct the tsc counter value */
if (cpu_has_tsc) {
res = (((u64)(*deltatsc)) * pm_100ms);
do_div(res, deltapm);
pr_info("APIC delta adjusted to PM-Timer: "
"%lu (%ld)\n", (unsigned long)res, *delta);
*delta = (long)res;
apic_printk(APIC_VERBOSE, "TSC delta adjusted to "
"PM-Timer: %lu (%ld) \n",
(unsigned long)res, *deltatsc);
*deltatsc = (long)res;
}
return 0;
@ -579,7 +591,7 @@ static int __init calibrate_APIC_clock(void)
struct clock_event_device *levt = &__get_cpu_var(lapic_events);
void (*real_handler)(struct clock_event_device *dev);
unsigned long deltaj;
long delta;
long delta, deltatsc;
int pm_referenced = 0;
local_irq_disable();
@ -609,9 +621,11 @@ static int __init calibrate_APIC_clock(void)
delta = lapic_cal_t1 - lapic_cal_t2;
apic_printk(APIC_VERBOSE, "... lapic delta = %ld\n", delta);
deltatsc = (long)(lapic_cal_tsc2 - lapic_cal_tsc1);
/* we trust the PM based calibration if possible */
pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
&delta);
&delta, &deltatsc);
/* Calculate the scaled math multiplication factor */
lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
@ -629,11 +643,10 @@ static int __init calibrate_APIC_clock(void)
calibration_result);
if (cpu_has_tsc) {
delta = (long)(lapic_cal_tsc2 - lapic_cal_tsc1);
apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
"%ld.%04ld MHz.\n",
(delta / LAPIC_CAL_LOOPS) / (1000000 / HZ),
(delta / LAPIC_CAL_LOOPS) % (1000000 / HZ));
(deltatsc / LAPIC_CAL_LOOPS) / (1000000 / HZ),
(deltatsc / LAPIC_CAL_LOOPS) % (1000000 / HZ));
}
apic_printk(APIC_VERBOSE, "..... host bus clock speed is "