From 780eef9492b16a1543a3b2ae9f9526a735fc9856 Mon Sep 17 00:00:00 2001 From: Tim Blechmann Date: Thu, 19 Feb 2009 17:34:03 +0100 Subject: [PATCH] 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 Signed-off-by: Robert Richter LKML-Reference: <20090303100412.GC10085@erda.amd.com> Cc: Signed-off-by: Ingo Molnar --- arch/x86/oprofile/op_model_ppro.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c index e9f80c744cf3..10131fbdaada 100644 --- a/arch/x86/oprofile/op_model_ppro.c +++ b/arch/x86/oprofile/op_model_ppro.c @@ -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 */