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 <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
LKML-Reference: <20090612080855[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 895c82e78455036810b21302cf2bea49a40466a1..275bc142cd5ddab2d530be5819744fbaafd831d9 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)))