Merge remote-tracking branch 'powerpc/next'

[karo-tx-linux.git] / arch / x86 / kernel / cpu / perf_event_intel_ds.c

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 84f236ab96b03459907662de8842958a3645d011..5db1c7755548e2ad472b2fbe5541125a45d90376 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -510,10 +510,11 @@ int intel_pmu_drain_bts_buffer(void)
                u64     flags;
        };
        struct perf_event *event = cpuc->events[INTEL_PMC_IDX_FIXED_BTS];
-       struct bts_record *at, *top;
+       struct bts_record *at, *base, *top;
        struct perf_output_handle handle;
        struct perf_event_header header;
        struct perf_sample_data data;
+       unsigned long skip = 0;
        struct pt_regs regs;
 
        if (!event)
@@ -522,10 +523,10 @@ int intel_pmu_drain_bts_buffer(void)
        if (!x86_pmu.bts_active)
                return 0;
 
-       at  = (struct bts_record *)(unsigned long)ds->bts_buffer_base;
-       top = (struct bts_record *)(unsigned long)ds->bts_index;
+       base = (struct bts_record *)(unsigned long)ds->bts_buffer_base;
+       top  = (struct bts_record *)(unsigned long)ds->bts_index;
 
-       if (top <= at)
+       if (top <= base)
                return 0;
 
        memset(&regs, 0, sizeof(regs));
@@ -534,6 +535,27 @@ int intel_pmu_drain_bts_buffer(void)
 
        perf_sample_data_init(&data, 0, event->hw.last_period);
 
+       /*
+        * BTS leaks kernel addresses in branches across the cpl boundary,
+        * such as traps or system calls, so unless the user is asking for
+        * kernel tracing (and right now it's not possible), we'd need to
+        * filter them out. But first we need to count how many of those we
+        * have in the current batch. This is an extra O(n) pass, however,
+        * it's much faster than the other one especially considering that
+        * n <= 2560 (BTS_BUFFER_SIZE / BTS_RECORD_SIZE * 15/16; see the
+        * alloc_bts_buffer()).
+        */
+       for (at = base; at < top; at++) {
+               /*
+                * Note that right now *this* BTS code only works if
+                * attr::exclude_kernel is set, but let's keep this extra
+                * check here in case that changes.
+                */
+               if (event->attr.exclude_kernel &&
+                   (kernel_ip(at->from) || kernel_ip(at->to)))
+                       skip++;
+       }
+
        /*
         * Prepare a generic sample, i.e. fill in the invariant fields.
         * We will overwrite the from and to address before we output
@@ -541,10 +563,16 @@ int intel_pmu_drain_bts_buffer(void)
         */
        perf_prepare_sample(&header, &data, event, &regs);
 
-       if (perf_output_begin(&handle, event, header.size * (top - at)))
+       if (perf_output_begin(&handle, event, header.size *
+                             (top - base - skip)))
                return 1;
 
-       for (; at < top; at++) {
+       for (at = base; at < top; at++) {
+               /* Filter out any records that contain kernel addresses. */
+               if (event->attr.exclude_kernel &&
+                   (kernel_ip(at->from) || kernel_ip(at->to)))
+                       continue;
+
                data.ip         = at->from;
                data.addr       = at->to;