Fix the NMI watchdog on Intel CoreDuo processor where the kernel would
get stuck during boot. The issue is related to errata AE49, where the
PERFEVTSEL1 counter does not have a working enable bit. Thus it is not
possible to use it for NMI.
The patch creates a dedicated wd_ops for CoreDuo which falls back to
using PERFEVTSEL0. The other Intel processors supporting the
architectural PMU will keep on using PERFEVTSEL1 as this allows other
subsystems, such as perfmon, to use PERFEVTSEL0 for PEBS monitoring in
particular. Bug initially reported by Daniel Walker.
AK: Added comments
Signed-off-by: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The performance counters on K7 are only 48 bits wide, so using bit 63 to
check if the counter overflowed is wrong. Let's use bit 47 instead.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I got an oops while booting a 32bit kernel on KVM because it doesn't
implement performance counters used by the NMI watchdog. Handle this
case.
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Intel PerfMon NMI watchdog reserves the first performance counter,
but uses the second one. Make it correctly reserve the second one.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With this change it works again when the nmi watchdog is disabled.
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Stephane Eranian <eranian@hpl.hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix oops triggered during: echo 0 > /proc/sys/kernel/nmi_watchdog
The culprit seems to be 09198e6850:
[PATCH] i386: Clean up NMI watchdog code
In two places, the parameters to release_{evntsel,perfctr}_nmi
got interchanged during the cleanup.
Fix interchanged parameters to release_{evntsel,perfctr}_nmi.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Stephane Eranian <eranian@hpl.hp.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When disabled through /proc/sys/kernel/nmi_watchdog, the NMI watchdog uses the
stop() method directly, which does not decrement the activity counter, leading
to a BUG(). Use the wrapper function instead to fix that.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At system boot time, the NMI watchdog no longer reserved its MSRs, allowing
other subsystems to mess with them. Fix that.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Introduce a wd_ops structure
- Convert the various nmi watchdogs over to it
- This allows to split the perfctr reservation from the watchdog
setup cleanly.
- Do perfctr reservation globally as it should have always been
- Remove dead code referenced only by unused EXPORT_SYMBOLs
Signed-off-by: Andi Kleen <ak@suse.de>
