drm/i915/display: Fix out-of-bounds access in pipe-related tracepoints

drm/i915/display: Fix out-of-bounds access in pipe-related tracepoints

Some display trace events use array members to store frame and scanline
counts for each pipe. However, those arrays are declared with 3 as the
hardcoded size, which cause out-of-bounds access when the trace event is
enabled on a platform that contains pipe D.

For example, when looking at the last 10 intel_pipe_enable events after
running IGT's testdisplay, we see the following on a MTL machine that
has pipe D available:

    $ trace-cmd report -R -F intel_pipe_enable \
    > | tail \
    > | sed 's,\(frame=.*\) \(scanline=.*\),\n\t   \1\n\t\2,'
         testdisplay-6715  [002] 17591.063491: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[83, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [003] 17591.264742: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[89, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [003] 17591.464541: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[8f, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [001] 17591.695827: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[95, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [000] 17591.915841: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[9a, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [000] 17592.127114: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[a0, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [002] 17592.358351: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[a8, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [002] 17592.580467: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[ae, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [000] 17592.950946: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[b8, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-6715  [004] 17593.079597: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[bf, 01, 00, 00, 01, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[00, 00, 00, 00, 3a, 04, 00, 00, 00, 00, 00, 00] pipe=1

Which shows zeros for pipe A's scanline counts. That happens because
pipe D's frame counts are overwriting them.

Let's fix that by making the arrays bring able to store info for all
possible pipes.

With the fix, we get the following:

    $ trace-cmd report -R -F intel_pipe_enable \
    > | tail \
    > | sed 's,\(frame=.*\) \(scanline=.*\),\n\t   \1\n\t\2,'
         testdisplay-7040  [003] 18067.489565: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[8c, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[8e, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [002] 18067.699312: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[92, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[58, 02, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [002] 18067.908868: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[98, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[58, 02, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [002] 18068.122802: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[9d, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[58, 02, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [003] 18068.331019: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[a2, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[e0, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [002] 18068.529067: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[a8, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[e0, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [003] 18068.742033: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[ae, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[e0, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [002] 18068.956229: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[b3, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[1f, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [002] 18069.295322: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[bb, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[7b, 08, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=0
         testdisplay-7040  [010] 18069.423527: intel_pipe_enable:     dev=0000:00:02.0
               frame=ARRAY[c2, 01, 00, 00, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
            scanline=ARRAY[d0, 05, 00, 00, 3a, 04, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe=1

Which makes more sense now.

Reviewed-by: Matt Roper <[email protected]>
Reviewed-by: Ville Syrjälä <[email protected]>
Signed-off-by: Gustavo Sousa <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]