linux-kernel - [PATCH] oprofile: don't set counter width from cpuid on core2

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Message-ID: <20090219173403.49871cac@thinkpad>
Date:	Thu, 19 Feb 2009 17:34:03 +0100
From:	Tim Blechmann <tim@...ngt.org>
To:	oprofile-list@...ts.sf.net, linux-kernel@...r.kernel.org
Cc:	Robert Richter <robert.richter@....com>,
	Andi Kleen <andi@...stfloor.org>
Subject: [PATCH] oprofile: don't set counter width from cpuid on core2

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Hash: SHA1

resetting the counter width of the performance counters on intel's
core2, 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@...ngt.org>
- ---
 arch/x86/oprofile/op_model_ppro.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index e9f80c7..ecba9f2 100644
- --- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -78,10 +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);
+
+		/* 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)
+			goto clear_all_counters;
+
 		if (counter_width < eax.split.bit_width)
 			counter_width = eax.split.bit_width;
 	}
 
+clear_all_counters:
+
 	/* clear all counters */
 	for (i = 0 ; i < num_counters; ++i) {
 		if (unlikely(!CTRL_IS_RESERVED(msrs, i)))
- -- 
1.6.1.2
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