[Intel-gfx] [PATCH 6/6] drm/i915/dp: Sanitize link common rate array lookups

Imre Deak
2021-10-18T09:42:19Z

Add an assert that lookups from the intel_dp->common_rates[] array
are always valid.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
drivers/gpu/drm/i915/display/intel_dp.c | 33 ++++++++++++-------------
1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index f8082eb8e7263..3869d454c10f0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -267,10 +267,19 @@ static int intel_dp_common_len_rate_limit(const struct intel_dp *intel_dp,
intel_dp->num_common_rates, max_rate);
}

+static int intel_dp_common_rate(struct intel_dp *intel_dp, int index)
+{
+ if (drm_WARN_ON(&dp_to_i915(intel_dp)->drm,
+ index < 0 || index >= intel_dp->num_common_rates))
+ return 162000;
+
+ return intel_dp->common_rates[index];
+}
+
/* Theoretical max between source and sink */
static int intel_dp_max_common_rate(struct intel_dp *intel_dp)
{
- return intel_dp->common_rates[intel_dp->num_common_rates - 1];
+ return intel_dp_common_rate(intel_dp, intel_dp->num_common_rates - 1);
}

/* Theoretical max between source and sink */
@@ -610,13 +619,13 @@ int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
if (index > 0) {
if (intel_dp_is_edp(intel_dp) &&
!intel_dp_can_link_train_fallback_for_edp(intel_dp,
- intel_dp->common_rates[index - 1],
+ intel_dp_common_rate(intel_dp, index - 1),
lane_count)) {
drm_dbg_kms(&i915->drm,
"Retrying Link training for eDP with same parameters\n");
return 0;
}
- intel_dp->max_link_rate = intel_dp->common_rates[index - 1];
+ intel_dp->max_link_rate = intel_dp_common_rate(intel_dp, index - 1);
intel_dp->max_link_lane_count = lane_count;
} else if (lane_count > 1) {
if (intel_dp_is_edp(intel_dp) &&
@@ -1056,14 +1065,11 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
int
intel_dp_max_link_rate(struct intel_dp *intel_dp)
{
- struct drm_i915_private *i915 = dp_to_i915(intel_dp);
int len;

len = intel_dp_common_len_rate_limit(intel_dp, intel_dp->max_link_rate);
- if (drm_WARN_ON(&i915->drm, len <= 0))
- return 162000;

- return intel_dp->common_rates[len - 1];
+ return intel_dp_common_rate(intel_dp, len - 1);
}

int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
@@ -1260,7 +1266,7 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
output_bpp);

for (i = 0; i < intel_dp->num_common_rates; i++) {
- link_rate = intel_dp->common_rates[i];
+ link_rate = intel_dp_common_rate(intel_dp, i);
if (link_rate < limits->min_rate ||
link_rate > limits->max_rate)
continue;
@@ -1508,17 +1514,10 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
&pipe_config->hw.adjusted_mode;
struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
struct link_config_limits limits;
- int common_len;
int ret;

- common_len = intel_dp_common_len_rate_limit(intel_dp,
- intel_dp->max_link_rate);
-
- /* No common link rates between source and sink */
- drm_WARN_ON(encoder->base.dev, common_len <= 0);
-
- limits.min_rate = intel_dp->common_rates[0];
- limits.max_rate = intel_dp->common_rates[common_len - 1];
+ limits.min_rate = intel_dp_common_rate(intel_dp, 0);
+ limits.max_rate = intel_dp_max_link_rate(intel_dp);

limits.min_lane_count = 1;
limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
--
2.27.0