perf_counter/x86: Add a quirk for Atom processors

The fixed-function performance counters do not work on current Atom
processors. Use the general-purpose ones instead.

Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20090612080855.GA2286@ywang-moblin2.bj.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 895c82e..275bc14 100644 (file)
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -968,6 +968,13 @@ fixed_mode_idx(struct perf_counter *counter, struct hw_perf_counter *hwc)
        if (!x86_pmu.num_counters_fixed)
                return -1;
 
+       /*
+        * Quirk, IA32_FIXED_CTRs do not work on current Atom processors:
+        */
+       if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
+                                       boot_cpu_data.x86_model == 28)
+               return -1;
+
        event = hwc->config & ARCH_PERFMON_EVENT_MASK;
 
        if (unlikely(event == x86_pmu.event_map(PERF_COUNT_HW_INSTRUCTIONS)))