[PATCH v4 2/3] drm: Add Gamma and Degamma LUT sizes props to drm_crtc to validate.

[Mark Yacoub]

From: Mark Yacoub <markyacoub@xxxxxxxxxx>

[Why]
1. drm_atomic_helper_check doesn't check for the LUT sizes of either Gamma
or Degamma props in the new CRTC state, allowing any invalid size to
be passed on.
2. Each driver has its own LUT size, which could also be different for
legacy users.

[How]
1. Create |degamma_lut_size| and |gamma_lut_size| to save the LUT sizes
assigned by the driver when it's initializing its color and CTM
management.
2. Create drm_atomic_helper_check_crtc which is called by
drm_atomic_helper_check to check the LUT sizes saved in drm_crtc that
they match the sizes in the new CRTC state.
3. As the LUT size check now happens in drm_atomic_helper_check, remove
the lut check in intel_color.c

Resolves: igt@kms_color@pipe-A-invalid-gamma-lut-sizes on MTK
Tested on Zork (amdgpu) and Jacuzzi (mediatek), volteer (TGL)

v3:
1. Check for lut pointer inside drm_check_lut_size.

v2:
1. Remove the rename to a parent commit.
2. Create a drm drm_check_lut_size instead of intel only function.

v1:
1. Fix typos
2. Remove the LUT size check from intel driver
3. Rename old LUT check to indicate it's a channel change

Signed-off-by: Mark Yacoub <markyacoub@xxxxxxxxxxxx>
---
 drivers/gpu/drm/drm_atomic_helper.c        | 52 ++++++++++++++++++++++
 drivers/gpu/drm/drm_color_mgmt.c           | 19 ++++++++
 drivers/gpu/drm/i915/display/intel_color.c | 32 ++++++-------
 include/drm/drm_atomic_helper.h            |  1 +
 include/drm/drm_color_mgmt.h               |  3 ++
 include/drm/drm_crtc.h                     | 11 +++++
 6 files changed, 99 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index bc3487964fb5e..548e5d8221fb4 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -929,6 +929,54 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_planes);
 
+/**
+ * drm_atomic_helper_check_crtcs - validate state object for CRTC changes
+ * @state: the driver state object
+ *
+ * Check the CRTC state object such as the Gamma/Degamma LUT sizes if the new
+ * state holds them.
+ *
+ * RETURNS:
+ * Zero for success or -errno
+ */
+int drm_atomic_helper_check_crtcs(struct drm_atomic_state *state)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *new_crtc_state;
+	int i;
+
+	for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
+		if (!new_crtc_state->color_mgmt_changed)
+			continue;
+
+		if (drm_check_lut_size(new_crtc_state->gamma_lut,
+				       crtc->gamma_lut_size) ||
+		    drm_check_lut_size(new_crtc_state->gamma_lut,
+				       crtc->gamma_size)) {
+			drm_dbg_state(
+				state->dev,
+				"Invalid Gamma LUT size. Expected %u/%u, got %u.\n",
+				crtc->gamma_lut_size, crtc->gamma_size,
+				drm_color_lut_size(new_crtc_state->gamma_lut));
+			return -EINVAL;
+		}
+
+		if (drm_check_lut_size(new_crtc_state->degamma_lut,
+				       crtc->degamma_lut_size)) {
+			drm_dbg_state(
+				state->dev,
+				"Invalid Degamma LUT size. Expected %u, got %u.\n",
+				crtc->degamma_lut_size,
+				drm_color_lut_size(
+					new_crtc_state->degamma_lut));
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_atomic_helper_check_crtcs);
+
 /**
  * drm_atomic_helper_check - validate state object
  * @dev: DRM device
@@ -974,6 +1022,10 @@ int drm_atomic_helper_check(struct drm_device *dev,
 	if (ret)
 		return ret;
 
+	ret = drm_atomic_helper_check_crtcs(state);
+	if (ret)
+		return ret;
+
 	if (state->legacy_cursor_update)
 		state->async_update = !drm_atomic_helper_async_check(dev, state);
 
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 16a07f84948f3..c85094223b535 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -166,6 +166,7 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
 	struct drm_mode_config *config = &dev->mode_config;
 
 	if (degamma_lut_size) {
+		crtc->degamma_lut_size = degamma_lut_size;
 		drm_object_attach_property(&crtc->base,
 					   config->degamma_lut_property, 0);
 		drm_object_attach_property(&crtc->base,
@@ -178,6 +179,7 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
 					   config->ctm_property, 0);
 
 	if (gamma_lut_size) {
+		crtc->gamma_lut_size = gamma_lut_size;
 		drm_object_attach_property(&crtc->base,
 					   config->gamma_lut_property, 0);
 		drm_object_attach_property(&crtc->base,
@@ -506,6 +508,23 @@ const char *drm_get_color_range_name(enum drm_color_range range)
 	return color_range_name[range];
 }
 
+/**
+ * drm_check_lut_size - Checks if LUT size matches the driver expected size.
+ * @lut: blob containing the LUT
+ * @expected_size: driver expected LUT size
+ *
+ * Returns -EINVAL on mismatch, 0 on match.
+ */
+int drm_check_lut_size(const struct drm_property_blob *lut,
+		       uint32_t expected_size)
+{
+	if (!lut)
+		return 0;
+
+	return drm_color_lut_size(lut) != expected_size ? -EINVAL : 0;
+}
+EXPORT_SYMBOL(drm_check_lut_size);
+
 /**
  * drm_plane_create_color_properties - color encoding related plane properties
  * @plane: plane object
diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
index bde98a155c9f3..30c23294556b4 100644
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -1262,23 +1262,6 @@ intel_color_add_affected_planes(struct intel_crtc_state *new_crtc_state)
 	return 0;
 }
 
-static int check_lut_size(const struct drm_property_blob *lut, int expected)
-{
-	int len;
-
-	if (!lut)
-		return 0;
-
-	len = drm_color_lut_size(lut);
-	if (len != expected) {
-		DRM_DEBUG_KMS("Invalid LUT size; got %d, expected %d\n",
-			      len, expected);
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
 static int test_luts(const struct drm_property_blob *lut, u32 tests)
 {
 	const struct drm_color_lut *entry;
@@ -1336,9 +1319,20 @@ static int check_luts(const struct intel_crtc_state *crtc_state)
 	degamma_channels_tests = INTEL_INFO(dev_priv)->color.degamma_lut_tests;
 	gamma_channels_tests = INTEL_INFO(dev_priv)->color.gamma_lut_tests;
 
-	if (check_lut_size(degamma_lut, degamma_length) ||
-	    check_lut_size(gamma_lut, gamma_length))
+	if (drm_check_lut_size(degamma_lut, degamma_length)) {
+		drm_dbg_state(
+			&dev_priv->drm,
+			"Invalid Degamma LUT size. Expected %u, got %u.\n",
+			degamma_length, drm_color_lut_size(degamma_lut));
 		return -EINVAL;
+	}
+
+	if (drm_check_lut_size(gamma_lut, gamma_length)) {
+		drm_dbg_state(&dev_priv->drm,
+			      "Invalid Gamma LUT size. Expected %u, got %u.\n",
+			      degamma_length, drm_color_lut_size(gamma_lut));
+		return -EINVAL;
+	}
 
 	if (test_luts(degamma_lut, degamma_channels_tests) ||
 	    test_luts(gamma_lut, gamma_channels_tests))
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 4045e2507e11c..a22d32a7a8719 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -38,6 +38,7 @@ struct drm_atomic_state;
 struct drm_private_obj;
 struct drm_private_state;
 
+int drm_atomic_helper_check_crtcs(struct drm_atomic_state *state);
 int drm_atomic_helper_check_modeset(struct drm_device *dev,
 				struct drm_atomic_state *state);
 int drm_atomic_helper_check_plane_state(struct drm_plane_state *plane_state,
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index 3537f3eeb3872..cb2d74719f2d5 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -74,6 +74,9 @@ static inline int drm_color_lut_size(const struct drm_property_blob *blob)
 	return blob->length / sizeof(struct drm_color_lut);
 }
 
+int drm_check_lut_size(const struct drm_property_blob *lut,
+		       uint32_t expected_size);
+
 enum drm_color_encoding {
 	DRM_COLOR_YCBCR_BT601,
 	DRM_COLOR_YCBCR_BT709,
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 2deb15d7e1610..4fd1c9a4bbba8 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1072,6 +1072,17 @@ struct drm_crtc {
 	/** @funcs: CRTC control functions */
 	const struct drm_crtc_funcs *funcs;
 
+	/**
+	 * @degamma_lut_size: Size of degamma LUT.
+	 */
+	size_t degamma_lut_size;
+
+	/**
+	 * @gamma_lut_size: Size of Gamma LUT. Not used by legacy userspace such as
+	 * X, which doesn't support large lut sizes.
+	 */
+	size_t gamma_lut_size;
+
 	/**
 	 * @gamma_size: Size of legacy gamma ramp reported to userspace. Set up
 	 * by calling drm_mode_crtc_set_gamma_size().
-- 
2.34.0.rc0.344.g81b53c2807-goog