drm/panfrost: Add driver IOCTL for setting BO labels

Allow UM to label a BO for which it possesses a DRM handle.

Signed-off-by: Adrián Larumbe <[e-mail]>
Reviewed-by: Steven Price <[e-mail]>
Reviewed-by: Boris Brezillon <[e-mail]>
Signed-off-by: Steven Price <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/gpu/drm/panfrost/panfrost_drv.c

···
 	return ret;
 }
 
+static int panfrost_ioctl_set_label_bo(struct drm_device *ddev, void *data,
+				       struct drm_file *file)
+{
+	struct drm_panfrost_set_label_bo *args = data;
+	struct drm_gem_object *obj;
+	const char *label = NULL;
+	int ret = 0;
+
+	if (args->pad)
+		return -EINVAL;
+
+	obj = drm_gem_object_lookup(file, args->handle);
+	if (!obj)
+		return -ENOENT;
+
+	if (args->label) {
+		label = strndup_user(u64_to_user_ptr(args->label),
+				     PANFROST_BO_LABEL_MAXLEN);
+		if (IS_ERR(label)) {
+			ret = PTR_ERR(label);
+			if (ret == -EINVAL)
+				ret = -E2BIG;
+			goto err_put_obj;
+		}
+	}
+
+	/*
+	 * We treat passing a label of length 0 and passing a NULL label
+	 * differently, because even though they might seem conceptually
+	 * similar, future uses of the BO label might expect a different
+	 * behaviour in each case.
+	 */
+	panfrost_gem_set_label(obj, label);
+
+err_put_obj:
+	drm_gem_object_put(obj);
+
+	return ret;
+}
+
 int panfrost_unstable_ioctl_check(void)
 {
 	if (!unstable_ioctls)
···
 	PANFROST_IOCTL(PERFCNT_ENABLE,	perfcnt_enable,	DRM_RENDER_ALLOW),
 	PANFROST_IOCTL(PERFCNT_DUMP,	perfcnt_dump,	DRM_RENDER_ALLOW),
 	PANFROST_IOCTL(MADVISE,		madvise,	DRM_RENDER_ALLOW),
+	PANFROST_IOCTL(SET_LABEL_BO,	set_label_bo,	DRM_RENDER_ALLOW),
 };
 
 static void panfrost_gpu_show_fdinfo(struct panfrost_device *pfdev,
···
  * - 1.2 - adds AFBC_FEATURES query
  * - 1.3 - adds JD_REQ_CYCLE_COUNT job requirement for SUBMIT
  *       - adds SYSTEM_TIMESTAMP and SYSTEM_TIMESTAMP_FREQUENCY queries
+ * - 1.4 - adds SET_LABEL_BO
  */
 static const struct drm_driver panfrost_drm_driver = {
 	.driver_features	= DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ,
···
 	.name			= "panfrost",
 	.desc			= "panfrost DRM",
 	.major			= 1,
-	.minor			= 3,
+	.minor			= 4,
 
 	.gem_create_object	= panfrost_gem_create_object,
 	.gem_prime_import_sg_table = panfrost_gem_prime_import_sg_table,

drivers/gpu/drm/panfrost/panfrost_gem.h

···
 
 struct panfrost_mmu;
 
+#define PANFROST_BO_LABEL_MAXLEN	4096
+
 struct panfrost_gem_object {
 	struct drm_gem_shmem_object base;
 	struct sg_table *sgts;

include/uapi/drm/panfrost_drm.h

···
 #define DRM_PANFROST_PERFCNT_ENABLE		0x06
 #define DRM_PANFROST_PERFCNT_DUMP		0x07
 #define DRM_PANFROST_MADVISE			0x08
+#define DRM_PANFROST_SET_LABEL_BO		0x09
 
 #define DRM_IOCTL_PANFROST_SUBMIT		DRM_IOW(DRM_COMMAND_BASE + DRM_PANFROST_SUBMIT, struct drm_panfrost_submit)
 #define DRM_IOCTL_PANFROST_WAIT_BO		DRM_IOW(DRM_COMMAND_BASE + DRM_PANFROST_WAIT_BO, struct drm_panfrost_wait_bo)
···
 #define DRM_IOCTL_PANFROST_GET_PARAM		DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_GET_PARAM, struct drm_panfrost_get_param)
 #define DRM_IOCTL_PANFROST_GET_BO_OFFSET	DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_GET_BO_OFFSET, struct drm_panfrost_get_bo_offset)
 #define DRM_IOCTL_PANFROST_MADVISE		DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_MADVISE, struct drm_panfrost_madvise)
+#define DRM_IOCTL_PANFROST_SET_LABEL_BO		DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_SET_LABEL_BO, struct drm_panfrost_set_label_bo)
 
 /*
  * Unstable ioctl(s): only exposed when the unsafe unstable_ioctls module
···
 	__u32 handle;         /* in, GEM handle */
 	__u32 madv;           /* in, PANFROST_MADV_x */
 	__u32 retained;       /* out, whether backing store still exists */
+};
+
+/**
+ * struct drm_panfrost_set_label_bo - ioctl argument for labelling Panfrost BOs.
+ */
+struct drm_panfrost_set_label_bo {
+	/** @handle: Handle of the buffer object to label. */
+	__u32 handle;
+
+	/**  @pad: MBZ. */
+	__u32 pad;
+
+	/**
+	 * @label: User pointer to a NUL-terminated string
+	 *
+	 * Length cannot be greater than 4096.
+	 * NULL is permitted and means clear the label.
+	 */
+	__u64 label;
 };
 
 /* Definitions for coredump decoding in user space */