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

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=6296Patch-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
......@@ -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);
......
......@@ -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);
......
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