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>
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index e9f80c7..10131fb 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -78,8 +78,18 @@
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 */