[PATCH 1/2] drm/vc4: Fix termination of the initial scan for branch targets.

[PATCH 1/2] drm/vc4: Fix termination of the initial scan for branch targets.

[Eric Anholt]

The loop is scanning until the original max_ip (size of the BO), but
we want to not examine any code after the PROG_END's delay slots.
There was a block trying to do that, except that we had some early
continue statements if the signal wasn't a PROG_END or a BRANCH.

The failure mode would be that a valid shader is rejected because some
undefined memory after the PROG_END slots is parsed as a branch and
the rest of its setup is illegal.  I haven't seen this in the wild,
but valgrind was complaining when about this up in the userland
simulator mode.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_validate_shaders.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_validate_shaders.c b/drivers/gpu/drm/vc4/vc4_validate_shaders.c
index 2543cf5b8b51..917321ce832f 100644
--- a/drivers/gpu/drm/vc4/vc4_validate_shaders.c
+++ b/drivers/gpu/drm/vc4/vc4_validate_shaders.c
@@ -608,9 +608,7 @@ static bool
 vc4_validate_branches(struct vc4_shader_validation_state *validation_state)
 {
 	uint32_t max_branch_target = 0;
-	bool found_shader_end = false;
 	int ip;
-	int shader_end_ip = 0;
 	int last_branch = -2;
 
 	for (ip = 0; ip < validation_state->max_ip; ip++) {
@@ -621,8 +619,13 @@ vc4_validate_branches(struct vc4_shader_validation_state *validation_state)
 		uint32_t branch_target_ip;
 
 		if (sig == QPU_SIG_PROG_END) {
-			shader_end_ip = ip;
-			found_shader_end = true;
+			/* There are two delay slots after program end is
+			 * signaled that are still executed, then we're
+			 * finished.  validation_state->max_ip is the
+			 * instruction after the last valid instruction in the
+			 * program.
+			 */
+			validation_state->max_ip = ip + 3;
 			continue;
 		}
 
@@ -676,15 +679,9 @@ vc4_validate_branches(struct vc4_shader_validation_state *validation_state)
 		}
 		set_bit(after_delay_ip, validation_state->branch_targets);
 		max_branch_target = max(max_branch_target, after_delay_ip);
-
-		/* There are two delay slots after program end is signaled
-		 * that are still executed, then we're finished.
-		 */
-		if (found_shader_end && ip == shader_end_ip + 2)
-			break;
 	}
 
-	if (max_branch_target > shader_end_ip) {
+	if (max_branch_target > validation_state->max_ip - 3) {
 		DRM_ERROR("Branch landed after QPU_SIG_PROG_END");
 		return false;
 	}
-- 
2.10.1

[PATCH 2/2] drm/vc4: Add support for rendering with ETC1 textures.

[Eric Anholt]

The validation for it ends up being quite simple, but I hadn't got
around to it before merging the driver.  For backwards compatibility,
we also need to add a flag so that the userspace GL driver can easily
tell if the kernel will allow ETC1 textures (on an old kernel, it will
continue to convert to RGBA8)

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_drv.c      | 1 +
 drivers/gpu/drm/vc4/vc4_validate.c | 7 +++++++
 include/uapi/drm/vc4_drm.h         | 1 +
 3 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 8703f56b7947..b087404c2784 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -78,6 +78,7 @@ static int vc4_get_param_ioctl(struct drm_device *dev, void *data,
 		pm_runtime_put(&vc4->v3d->pdev->dev);
 		break;
 	case DRM_VC4_PARAM_SUPPORTS_BRANCHES:
+	case DRM_VC4_PARAM_SUPPORTS_ETC1:
 		args->value = true;
 		break;
 	default:
diff --git a/drivers/gpu/drm/vc4/vc4_validate.c b/drivers/gpu/drm/vc4/vc4_validate.c
index 26503e307438..e18f88203d32 100644
--- a/drivers/gpu/drm/vc4/vc4_validate.c
+++ b/drivers/gpu/drm/vc4/vc4_validate.c
@@ -644,6 +644,13 @@ reloc_tex(struct vc4_exec_info *exec,
 		cpp = 1;
 		break;
 	case VC4_TEXTURE_TYPE_ETC1:
+		/* ETC1 is arranged as 64-bit blocks, where each block is 4x4
+		 * pixels.
+		 */
+		cpp = 8;
+		width = (width + 3) >> 2;
+		height = (height + 3) >> 2;
+		break;
 	case VC4_TEXTURE_TYPE_BW1:
 	case VC4_TEXTURE_TYPE_A4:
 	case VC4_TEXTURE_TYPE_A1:
diff --git a/include/uapi/drm/vc4_drm.h b/include/uapi/drm/vc4_drm.h
index ad7edc3edf7c..69caa21f0cb2 100644
--- a/include/uapi/drm/vc4_drm.h
+++ b/include/uapi/drm/vc4_drm.h
@@ -286,6 +286,7 @@ struct drm_vc4_get_hang_state {
 #define DRM_VC4_PARAM_V3D_IDENT1		1
 #define DRM_VC4_PARAM_V3D_IDENT2		2
 #define DRM_VC4_PARAM_SUPPORTS_BRANCHES		3
+#define DRM_VC4_PARAM_SUPPORTS_ETC1		4
 
 struct drm_vc4_get_param {
 	__u32 param;
-- 
2.10.1