Re: [PATCH 2/3] perf_events: fix validation of events using an extra reg (v3)

[Peter Zijlstra <peterz@infradead.org>]

On Mon, 2011-05-23 at 18:12 +0200, Stephane Eranian wrote:
> +static struct cpu_hw_events *allocate_fake_cpuc(void)
> +{
> +       struct cpu_hw_events *cpuc;
> +       int cpu = smp_processor_id();
> +
> +       cpuc = kzalloc(sizeof(*cpuc), GFP_KERNEL);
> +       if (!cpuc)
> +               return ERR_PTR(-ENOMEM);
> +
> +       /* only needed, if we have extra_regs */
> +       if (x86_pmu.extra_regs) {
> +               cpuc->shared_regs = allocate_shared_regs(cpu);
> +               if (!cpuc->shared_regs)
> +                       goto error;
> +       }
> +       return cpuc;
> +error:
> +       free_fake_cpuc(cpuc);
> +       return ERR_PTR(-ENOMEM);
> +} 

Ingo found a case where that use of allocate_shared_regs() failed to
compile but didn't provide a .config. I suspect its CONFIG_CPU_SUP_INTEL
and the below should fix it. I will try to push that again later today.

---
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 41178c8..cf90e31 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1528,4 +1623,9 @@ static int intel_pmu_init(void)
 	return 0;
 }
 
+static struct intel_shared_regs *allocate_shared_regs(int cpu)
+{
+	return NULL;
+}
+
 #endif /* CONFIG_CPU_SUP_INTEL */