7ad7a5acfb
The mxsfb driver will crash if the mxsfb DT node has a subnode, but the content of the subnode is not of-graph binding with an endpoint linking to panel. The crash was triggered by providing old-style panel bindings to the mxsfb driver instead of the new of-graph ones. The problem happens in mxsfb_create_output(), which is invoked from mxsfb_load(). The mxsfb_create_output() iterates over all mxsfb DT subnode endpoints and tries to bind a panel on each endpoint. If there is any problem binding the panel, that is, mxsfb->panel == NULL, this function will return an error code, otherwise success 0 is returned. If the subnodes do not specify of-graph binding with an endpoint, the iteration over endpoints in mxsfb_create_output() will have zero cycles and the function will immediatelly return 0, but the mxsfb->panel will remain NULL. This is propagated back into the mxsfb_load(), which does not detect any problem and expects that the mxsfb->panel is valid, thus calls mxsfb_panel_attach(). But since mxsfb->panel == NULL, mxsfb_panel_attach() is called with first argument NULL and this crashes the kernel. This patch fixes the problem by explicitly checking for valid mxsfb->panel at the end of the iteration in mxsfb_create_output(). Signed-off-by: Marek Vasut <marex@denx.de> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dave Airlie <airlied@redhat.com> Cc: Stefan Agner <stefan@agner.ch> Cc: Breno Matheus Lima <brenomatheus@gmail.com> Tested-by: Breno Lima <breno.lima@nxp.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
136 lines
3.6 KiB
C
136 lines
3.6 KiB
C
/*
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* Copyright (C) 2016 Marek Vasut <marex@denx.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/of_graph.h>
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#include <drm/drm_atomic.h>
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#include <drm/drm_atomic_helper.h>
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#include <drm/drm_crtc.h>
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#include <drm/drm_crtc_helper.h>
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#include <drm/drm_fb_cma_helper.h>
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#include <drm/drm_gem_cma_helper.h>
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#include <drm/drm_panel.h>
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#include <drm/drm_plane_helper.h>
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#include <drm/drm_simple_kms_helper.h>
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#include <drm/drmP.h>
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#include "mxsfb_drv.h"
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static struct mxsfb_drm_private *
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drm_connector_to_mxsfb_drm_private(struct drm_connector *connector)
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{
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return container_of(connector, struct mxsfb_drm_private, connector);
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}
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static int mxsfb_panel_get_modes(struct drm_connector *connector)
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{
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struct mxsfb_drm_private *mxsfb =
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drm_connector_to_mxsfb_drm_private(connector);
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if (mxsfb->panel)
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return mxsfb->panel->funcs->get_modes(mxsfb->panel);
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return 0;
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}
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static const struct
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drm_connector_helper_funcs mxsfb_panel_connector_helper_funcs = {
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.get_modes = mxsfb_panel_get_modes,
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};
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static enum drm_connector_status
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mxsfb_panel_connector_detect(struct drm_connector *connector, bool force)
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{
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struct mxsfb_drm_private *mxsfb =
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drm_connector_to_mxsfb_drm_private(connector);
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if (mxsfb->panel)
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return connector_status_connected;
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return connector_status_disconnected;
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}
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static void mxsfb_panel_connector_destroy(struct drm_connector *connector)
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{
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struct mxsfb_drm_private *mxsfb =
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drm_connector_to_mxsfb_drm_private(connector);
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if (mxsfb->panel)
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drm_panel_detach(mxsfb->panel);
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drm_connector_unregister(connector);
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drm_connector_cleanup(connector);
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}
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static const struct drm_connector_funcs mxsfb_panel_connector_funcs = {
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.dpms = drm_atomic_helper_connector_dpms,
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.detect = mxsfb_panel_connector_detect,
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.fill_modes = drm_helper_probe_single_connector_modes,
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.destroy = mxsfb_panel_connector_destroy,
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.reset = drm_atomic_helper_connector_reset,
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.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
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.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
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};
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static int mxsfb_attach_endpoint(struct drm_device *drm,
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const struct of_endpoint *ep)
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{
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struct mxsfb_drm_private *mxsfb = drm->dev_private;
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struct device_node *np;
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struct drm_panel *panel;
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int ret = -EPROBE_DEFER;
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np = of_graph_get_remote_port_parent(ep->local_node);
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panel = of_drm_find_panel(np);
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of_node_put(np);
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if (!panel)
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return -EPROBE_DEFER;
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mxsfb->connector.dpms = DRM_MODE_DPMS_OFF;
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mxsfb->connector.polled = 0;
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drm_connector_helper_add(&mxsfb->connector,
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&mxsfb_panel_connector_helper_funcs);
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ret = drm_connector_init(drm, &mxsfb->connector,
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&mxsfb_panel_connector_funcs,
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DRM_MODE_CONNECTOR_Unknown);
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if (!ret)
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mxsfb->panel = panel;
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return ret;
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}
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int mxsfb_create_output(struct drm_device *drm)
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{
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struct mxsfb_drm_private *mxsfb = drm->dev_private;
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struct device_node *ep_np = NULL;
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struct of_endpoint ep;
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int ret;
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for_each_endpoint_of_node(drm->dev->of_node, ep_np) {
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ret = of_graph_parse_endpoint(ep_np, &ep);
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if (!ret)
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ret = mxsfb_attach_endpoint(drm, &ep);
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if (ret) {
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of_node_put(ep_np);
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return ret;
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}
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}
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if (!mxsfb->panel)
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return -EPROBE_DEFER;
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return 0;
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}
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