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authorTim Blechmann <tim@klingt.org>2009-02-19 17:34:03 +0100
committerIngo Molnar <mingo@elte.hu>2009-03-03 12:04:22 +0100
commit780eef9492b16a1543a3b2ae9f9526a735fc9856 (patch)
treed3c4942a98845558d45e4b36d5350ebf41cde524 /arch/x86/oprofile
parent0fc59d3a01820765e5f3a723733728758b0cf577 (diff)
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>
Diffstat (limited to 'arch/x86/oprofile')
-rw-r--r--arch/x86/oprofile/op_model_ppro.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index e9f80c744cf..10131fbdaad 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 */