drm/i915: Limit the for_each_set_bit() to the valid range

Let static analyzers (smatch) know that we are not going to wander off
the end of the array by providing a tight upper bound:

drivers/gpu/drm/i915/intel_display.c:9532 hsw_get_transcoder_state() error: buffer overflow 'dev_priv->__info.trans_offsets' 6 <= 31

References: 0716931a82b4 ("drm/i915/icl: fix transcoder state readout")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Madhav Chauhan <madhav.chauhan@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190116155421.7660-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8d6d7ae311f445e385eba5aeeea2151f703045bc..9a6fbce1cafc3d698a79b6558a008b2b1d51de56 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9526,7 +9526,9 @@ static bool hsw_get_transcoder_state(struct intel_crtc *crtc,
         * XXX: Do intel_display_power_get_if_enabled before reading this (for
         * consistency and less surprising code; it's in always on power).
         */
-       for_each_set_bit(panel_transcoder, &panel_transcoder_mask, 32) {
+       for_each_set_bit(panel_transcoder,
+                        &panel_transcoder_mask,
+                        ARRAY_SIZE(INTEL_INFO(dev_priv)->trans_offsets)) {
                enum pipe trans_pipe;
 
                tmp = I915_READ(TRANS_DDI_FUNC_CTL(panel_transcoder));