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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/apic_32.c

@@ -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

@@ -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