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Commit 827014be authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

x86: TSC: use one set of reference variables 



Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d683ef7a

arch/x86/kernel/tsc.c

+11 −11
Original line number Diff line number Diff line
@@ -104,7 +104,7 @@ __setup("notsc", notsc_setup); 
/*

 * Read TSC and the reference counters. Take care of SMI disturbance

 */

static u64 tsc_read_refs(u64 *pm, u64 *hpet)

static u64 tsc_read_refs(u64 *p, int hpet)

{

	u64 t1, t2;

	int i;
@@ -112,9 +112,9 @@ static u64 tsc_read_refs(u64 *pm, u64 *hpet) 
	for (i = 0; i < MAX_RETRIES; i++) {

		t1 = get_cycles();

		if (hpet)

			*hpet = hpet_readl(HPET_COUNTER) & 0xFFFFFFFF;

			*p = hpet_readl(HPET_COUNTER) & 0xFFFFFFFF;

		else

			*pm = acpi_pm_read_early();

			*p = acpi_pm_read_early();

		t2 = get_cycles();

		if ((t2 - t1) < SMI_TRESHOLD)

			return t2;
@@ -228,7 +228,7 @@ static unsigned long pit_calibrate_tsc(void) 
 */

unsigned long native_calibrate_tsc(void)

{

	u64 tsc1, tsc2, delta, pm1, pm2, hpet1, hpet2;

	u64 tsc1, tsc2, delta, ref1, ref2;

	unsigned long tsc_pit_min = ULONG_MAX, tsc_ref_min = ULONG_MAX;

	unsigned long flags;

	int hpet = is_hpet_enabled(), i;
@@ -267,16 +267,16 @@ unsigned long native_calibrate_tsc(void) 
		 * read the end value.

		 */

		local_irq_save(flags);

		tsc1 = tsc_read_refs(&pm1, hpet ? &hpet1 : NULL);

		tsc1 = tsc_read_refs(&ref1, hpet);

		tsc_pit_khz = pit_calibrate_tsc();

		tsc2 = tsc_read_refs(&pm2, hpet ? &hpet2 : NULL);

		tsc2 = tsc_read_refs(&ref2, hpet);

		local_irq_restore(flags);



		/* Pick the lowest PIT TSC calibration so far */

		tsc_pit_min = min(tsc_pit_min, tsc_pit_khz);



		/* hpet or pmtimer available ? */

		if (!hpet && !pm1 && !pm2)

		if (!hpet && !ref1 && !ref2)

			continue;



		/* Check, whether the sampling was disturbed by an SMI */
@@ -285,9 +285,9 @@ unsigned long native_calibrate_tsc(void) 


		tsc2 = (tsc2 - tsc1) * 1000000LL;

		if (hpet)

			tsc2 = calc_hpet_ref(tsc2, hpet1, hpet2);

			tsc2 = calc_hpet_ref(tsc2, ref1, ref2);

		else

			tsc2 = calc_pmtimer_ref(tsc2, pm1, pm2);

			tsc2 = calc_pmtimer_ref(tsc2, ref1, ref2);



		tsc_ref_min = min(tsc_ref_min, (unsigned long) tsc2);

	}
@@ -301,7 +301,7 @@ unsigned long native_calibrate_tsc(void) 
		       "SMI disturbance.\n");



		/* We don't have an alternative source, disable TSC */

		if (!hpet && !pm1 && !pm2) {

		if (!hpet && !ref1 && !ref2) {

			printk("TSC: No reference (HPET/PMTIMER) available\n");

			return 0;

		}
@@ -321,7 +321,7 @@ unsigned long native_calibrate_tsc(void) 
	}



	/* We don't have an alternative source, use the PIT calibration value */

	if (!hpet && !pm1 && !pm2) {

	if (!hpet && !ref1 && !ref2) {

		printk(KERN_INFO "TSC: Using PIT calibration value\n");

		return tsc_pit_min;

	}