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x86: oprofile: don't set counter width from cpuid on Core2 

Impact: fix stuck NMIs and non-working oprofile on certain CPUs

Resetting the counter width of the performance counters on Intel's
Core2 CPUs, breaks the delivery of NMIs, when running in x86_64 mode.

This should fix bug #12395:

  http://bugzilla.kernel.org/show_bug.cgi?id=12395

Signed-off-by: Tim Blechmann <tim@klingt.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <20090303100412.GC10085@erda.amd.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Tim Blechmann 2009-02-19 17:34:03 +01:00 committed by Ingo Molnar
parent 0fc59d3a01
commit 780eef9492
1 changed files with 12 additions and 2 deletions
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14
arch/x86/oprofile/op_model_ppro.c
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@ -78,8 +78,18 @@ static void ppro_setup_ctrs(struct op_msrs const * const msrs)
if (cpu_has_arch_perfmon) {
union cpuid10_eax eax;
eax.full = cpuid_eax(0xa);
if (counter_width < eax.split.bit_width)
counter_width = eax.split.bit_width;
/*
* For Core2 (family 6, model 15), don't reset the
* counter width:
*/
if (!(eax.split.version_id == 0 &&
current_cpu_data.x86 == 6 &&
current_cpu_data.x86_model == 15)) {
if (counter_width < eax.split.bit_width)
counter_width = eax.split.bit_width;
}
}
/* clear all counters */