1 files changed, 22 insertions, 12 deletions

diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c
index ffe666c2c6b5..5b804f96ad66 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_pt.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c
@@ -615,7 +615,8 @@ static int pt_buffer_reset_markers(struct pt_buffer *buf,
                                    struct perf_output_handle *handle)
 
 {
-        unsigned long idx, npages, end;
+        unsigned long head = local64_read(&buf->head);
+        unsigned long idx, npages, wakeup;
 
         if (buf->snapshot)
                 return 0;
@@ -634,17 +635,26 @@ static int pt_buffer_reset_markers(struct pt_buffer *buf,
         buf->topa_index[buf->stop_pos]->stop = 0;
         buf->topa_index[buf->intr_pos]->intr = 0;
 
-        if (pt_cap_get(PT_CAP_topa_multiple_entries)) {
-                npages = (handle->size + 1) >> PAGE_SHIFT;
-                end = (local64_read(&buf->head) >> PAGE_SHIFT) + npages;
-                /*if (end > handle->wakeup >> PAGE_SHIFT)
-                  end = handle->wakeup >> PAGE_SHIFT;*/
-                idx = end & (buf->nr_pages - 1);
-                buf->stop_pos = idx;
-                idx = (local64_read(&buf->head) >> PAGE_SHIFT) + npages - 1;
-                idx &= buf->nr_pages - 1;
-                buf->intr_pos = idx;
-        }
+        /* how many pages till the STOP marker */
+        npages = handle->size >> PAGE_SHIFT;
+
+        /* if it's on a page boundary, fill up one more page */
+        if (!offset_in_page(head + handle->size + 1))
+                npages++;
+
+        idx = (head >> PAGE_SHIFT) + npages;
+        idx &= buf->nr_pages - 1;
+        buf->stop_pos = idx;
+
+        wakeup = handle->wakeup >> PAGE_SHIFT;
+
+        /* in the worst case, wake up the consumer one page before hard stop */
+        idx = (head >> PAGE_SHIFT) + npages - 1;
+        if (idx > wakeup)
+                idx = wakeup;
+
+        idx &= buf->nr_pages - 1;
+        buf->intr_pos = idx;
 
         buf->topa_index[buf->stop_pos]->stop = 1;
         buf->topa_index[buf->intr_pos]->intr = 1;