drm: Add getfb2 ioctl

getfb2 allows us to pass multiple planes and modifiers, just like addfb2
over addfb.

Changes since v2:
 - add privilege checks from getfb1 since handles should only be
   returned to master/root

Changes since v1:
 - unused modifiers set to 0 instead of DRM_FORMAT_MOD_INVALID
 - update ioctl number
Signed-off-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Juston Li <juston.li@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191217034642.3814-1-juston.li@intel.com

drivers/gpu/drm/drm_crtc_internal.h

@@ -216,6 +216,8 @@ int drm_mode_rmfb_ioctl(struct drm_device *dev,
 			void *data, struct drm_file *file_priv);
 int drm_mode_getfb(struct drm_device *dev,
 		   void *data, struct drm_file *file_priv);
+int drm_mode_getfb2_ioctl(struct drm_device *dev,
+			  void *data, struct drm_file *file_priv);
 int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
 			   void *data, struct drm_file *file_priv);
 

drivers/gpu/drm/drm_framebuffer.c

@@ -31,6 +31,7 @@
 #include <drm/drm_file.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
+#include <drm/drm_gem.h>
 #include <drm/drm_print.h>
 #include <drm/drm_util.h>
 
@@ -548,7 +549,128 @@ int drm_mode_getfb(struct drm_device *dev,
 
 out:
 	drm_framebuffer_put(fb);
+	return ret;
+}
+
+/**
+ * drm_mode_getfb2 - get extended FB info
+ * @dev: drm device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: drm file for the ioctl call
+ *
+ * Lookup the FB given its ID and return info about it.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_getfb2_ioctl(struct drm_device *dev,
+			  void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_fb_cmd2 *r = data;
+	struct drm_framebuffer *fb;
+	unsigned int i;
+	int ret;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	fb = drm_framebuffer_lookup(dev, file_priv, r->fb_id);
+	if (!fb)
+		return -ENOENT;
+
+	/* For multi-plane framebuffers, we require the driver to place the
+	 * GEM objects directly in the drm_framebuffer. For single-plane
+	 * framebuffers, we can fall back to create_handle.
+	 */
+	if (!fb->obj[0] &&
+	    (fb->format->num_planes > 1 || !fb->funcs->create_handle)) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	r->height = fb->height;
+	r->width = fb->width;
+	r->pixel_format = fb->format->format;
+
+	r->flags = 0;
+	if (dev->mode_config.allow_fb_modifiers)
+		r->flags |= DRM_MODE_FB_MODIFIERS;
+
+	for (i = 0; i < ARRAY_SIZE(r->handles); i++) {
+		r->handles[i] = 0;
+		r->pitches[i] = 0;
+		r->offsets[i] = 0;
+		r->modifier[i] = 0;
+	}
+
+	for (i = 0; i < fb->format->num_planes; i++) {
+		r->pitches[i] = fb->pitches[i];
+		r->offsets[i] = fb->offsets[i];
+		if (dev->mode_config.allow_fb_modifiers)
+			r->modifier[i] = fb->modifier;
+	}
+
+	/* GET_FB2() is an unprivileged ioctl so we must not return a
+	 * buffer-handle to non master/root processes! To match GET_FB()
+	 * just return invalid handles (0) for non masters/root
+	 * rather than making GET_FB2() privileged.
+	 */
+	if (!drm_is_current_master(file_priv) && !capable(CAP_SYS_ADMIN)) {
+		ret = 0;
+		goto out;
+	}
 
+	for (i = 0; i < fb->format->num_planes; i++) {
+		int j;
+
+		/* If we reuse the same object for multiple planes, also
+		 * return the same handle.
+		 */
+		for (j = 0; j < i; j++) {
+			if (fb->obj[i] == fb->obj[j]) {
+				r->handles[i] = r->handles[j];
+				break;
+			}
+		}
+
+		if (r->handles[i])
+			continue;
+
+		if (fb->obj[i]) {
+			ret = drm_gem_handle_create(file_priv, fb->obj[i],
+						    &r->handles[i]);
+		} else {
+			WARN_ON(i > 0);
+			ret = fb->funcs->create_handle(fb, file_priv,
+						       &r->handles[i]);
+		}
+
+		if (ret != 0)
+			goto out;
+	}
+
+out:
+	if (ret != 0) {
+		/* Delete any previously-created handles on failure. */
+		for (i = 0; i < ARRAY_SIZE(r->handles); i++) {
+			int j;
+
+			if (r->handles[i])
+				drm_gem_handle_delete(file_priv, r->handles[i]);
+
+			/* Zero out any handles identical to the one we just
+			 * deleted.
+			 */
+			for (j = i + 1; j < ARRAY_SIZE(r->handles); j++) {
+				if (r->handles[j] == r->handles[i])
+					r->handles[j] = 0;
+			}
+		}
+	}
+
+	drm_framebuffer_put(fb);
 	return ret;
 }
 

drivers/gpu/drm/drm_ioctl.c

@@ -671,6 +671,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPROPERTY, drm_connector_property_set_ioctl, DRM_MASTER),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPBLOB, drm_mode_getblob_ioctl, 0),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB, drm_mode_getfb, 0),
+	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB2, drm_mode_getfb2_ioctl, 0),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb_ioctl, 0),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2_ioctl, 0),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb_ioctl, 0),

include/uapi/drm/drm.h

@@ -948,6 +948,8 @@ extern "C" {
 #define DRM_IOCTL_SYNCOBJ_TRANSFER	DRM_IOWR(0xCC, struct drm_syncobj_transfer)
 #define DRM_IOCTL_SYNCOBJ_TIMELINE_SIGNAL	DRM_IOWR(0xCD, struct drm_syncobj_timeline_array)
 
+#define DRM_IOCTL_MODE_GETFB2		DRM_IOWR(0xCE, struct drm_mode_fb_cmd2)
+
 /**
  * Device specific ioctls should only be in their respective headers
  * The device specific ioctl range is from 0x40 to 0x9f.