Commit d4d25dec authored by Maciej W. Rozycki's avatar Maciej W. Rozycki Committed by Ingo Molnar
Browse files

x86: fix NMI watchdog & 'stopped time' problem 

More than 3 years ago Niclas Gustafsson reported a 'stopped time'
problem:

> Watching the /proc/interrupts with 10s apart after the "stop".
>
> [root@s151 root]# more /proc/interrupts
>            CPU0
>   0:   66413955  local-APIC-edge  timer
[...]
> LOC:   67355837
> ERR:          0
> MIS:          0
> [root@s151 root]# more /proc/interrupts
>            CPU0
>   0:   66413955  local-APIC-edge  timer
[...]
> LOC:   67379568
> ERR:          0
> MIS:          0

This may be because buggy SMM firmware messes with the 8259A (configured
for a transparent mode -- yes that rare "local-APIC-edge" mode is tricky
;-) ) insanely.

this should resolve:

  http://bugzilla.kernel.org/show_bug.cgi?id=2544
  http://bugzilla.kernel.org/show_bug.cgi?id=6296



Patch-dusted-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 2ffbb837

arch/x86/kernel/io_apic_32.c

+10 −2
Original line number Diff line number Diff line
@@ -2166,6 +2166,10 @@ static inline void __init check_timer(void) 
{

	int apic1, pin1, apic2, pin2;

	int vector;

	unsigned int ver;



	ver = apic_read(APIC_LVR);

	ver = GET_APIC_VERSION(ver);



	/*

	 * get/set the timer IRQ vector:
@@ -2179,11 +2183,15 @@ static inline void __init check_timer(void) 
	 * mode for the 8259A whenever interrupts are routed

	 * through I/O APICs.  Also IRQ0 has to be enabled in

	 * the 8259A which implies the virtual wire has to be

	 * disabled in the local APIC.

	 * disabled in the local APIC.  Finally timer interrupts

	 * need to be acknowledged manually in the 8259A for

	 * timer_interrupt() and for the i82489DX when using

	 * the NMI watchdog.

	 */

	apic_write_around(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);

	init_8259A(1);

	timer_ack = 1;

	timer_ack = !cpu_has_tsc;

	timer_ack |= (nmi_watchdog == NMI_IO_APIC && !APIC_INTEGRATED(ver));

	if (timer_over_8254 > 0)

		enable_8259A_irq(0);

arch/x86/kernel/nmi_32.c

+7 −2
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 


#include <asm/smp.h>

#include <asm/nmi.h>

#include <asm/timer.h>



#include "mach_traps.h"
@@ -83,7 +84,7 @@ static int __init check_nmi_watchdog(void) 


	prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);

	if (!prev_nmi_count)

		return -1;

		goto error;



	printk(KERN_INFO "Testing NMI watchdog ... ");
@@ -117,7 +118,7 @@ static int __init check_nmi_watchdog(void) 
	if (!atomic_read(&nmi_active)) {

		kfree(prev_nmi_count);

		atomic_set(&nmi_active, -1);

		return -1;

		goto error;

	}

	printk("OK.\n");
@@ -128,6 +129,10 @@ static int __init check_nmi_watchdog(void) 


	kfree(prev_nmi_count);

	return 0;

error:

	timer_ack = !cpu_has_tsc;



	return -1;

}

/* This needs to happen later in boot so counters are working */

late_initcall(check_nmi_watchdog);

CRA Git | Maintained and supported by SUSTech CRA and CCSE