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Commit c2b84b30 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

x86: sanity check APIC timer frequency 



Check the APIC timer calibration result for sanity. When the frequency
is out of range, issue a warning and disable the local APIC timer.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 387faedb

arch/x86/kernel/apic_32.c

+13 −0
Original line number Diff line number Diff line
@@ -470,6 +470,19 @@ void __init setup_boot_APIC_clock(void) 


	local_apic_timer_verify_ok = 1;



	/*

	 * Do a sanity check on the APIC calibration result

	 */

	if (calibration_result < (1000000 / HZ)) {

		local_irq_enable();

		printk(KERN_WARNING

		       "APIC frequency too slow, disabling apic timer\n");

		/* No broadcast on UP ! */

		if (num_possible_cpus() > 1)

			setup_APIC_timer();

		return;

	}



	/* We trust the pm timer based calibration */

	if (!pm_referenced) {

		apic_printk(APIC_VERBOSE, "... verify APIC timer\n");

arch/x86/kernel/apic_64.c

+12 −0
Original line number Diff line number Diff line
@@ -383,6 +383,18 @@ void __init setup_boot_APIC_clock(void) 
	printk(KERN_INFO "Using local APIC timer interrupts.\n");

	calibrate_APIC_clock();



	/*

	 * Do a sanity check on the APIC calibration result

	 */

	if (calibration_result < (1000000 / HZ)) {

		printk(KERN_WARNING

		       "APIC frequency too slow, disabling apic timer\n");

		/* No broadcast on UP ! */

		if (num_possible_cpus() > 1)

			setup_APIC_timer();

		return;

	}



	/*

	 * If nmi_watchdog is set to IO_APIC, we need the

	 * PIT/HPET going.  Otherwise register lapic as a dummy