i386: Fix perfctr watchdog on core duo

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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>

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Stephane Eranian 2007-09-06 16:59:51 +02:00 • committed by Linus Torvalds

parent b8da0d1c27

commit 23d5ea5d3e

1 changed files with 22 additions and 6 deletions

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arch/i386/kernel/cpu/perfctr-watchdog.c

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