From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 30 Jan 2008 12:33:04 +0000 (+0100)
Subject: x86: sanity check APIC timer frequency
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c2b84b30b8c8bbccf4d2e32f8a3a70ad09ba9ab8;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

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>
---

diff --git a/arch/x86/kernel/apic_32.c b/arch/x86/kernel/apic_32.c
index cbcf72cde956..20d4dbc42e6e 100644
--- a/arch/x86/kernel/apic_32.c
+++ b/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");
diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c
index d1a696673d9d..731b48660fc4 100644
--- a/arch/x86/kernel/apic_64.c
+++ b/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