1 files changed, 87 insertions, 20 deletions

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index ac90118b9e7a..dc4446d589e7 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -320,6 +320,9 @@ static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr
 	hdr->broadcast = (buf[idx] >> 7) & 0x1;
 	hdr->path_msg = (buf[idx] >> 6) & 0x1;
 	hdr->msg_len = buf[idx] & 0x3f;
+	if (hdr->msg_len < 1)		/* min space for body CRC */
+		return false;
+
 	idx++;
 	hdr->somt = (buf[idx] >> 7) & 0x1;
 	hdr->eomt = (buf[idx] >> 6) & 0x1;
@@ -3697,8 +3700,7 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 		ret = 0;
 		mgr->payload_id_table_cleared = false;
 
-		memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
-		memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
+		mgr->reset_rx_state = true;
 	}
 
 out_unlock:
@@ -3856,6 +3858,11 @@ out_fail:
 }
 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
 
+static void reset_msg_rx_state(struct drm_dp_sideband_msg_rx *msg)
+{
+	memset(msg, 0, sizeof(*msg));
+}
+
 static bool
 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
 		      struct drm_dp_mst_branch **mstb)
@@ -3934,6 +3941,34 @@ drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
 	return true;
 }
 
+static int get_msg_request_type(u8 data)
+{
+	return data & 0x7f;
+}
+
+static bool verify_rx_request_type(struct drm_dp_mst_topology_mgr *mgr,
+				   const struct drm_dp_sideband_msg_tx *txmsg,
+				   const struct drm_dp_sideband_msg_rx *rxmsg)
+{
+	const struct drm_dp_sideband_msg_hdr *hdr = &rxmsg->initial_hdr;
+	const struct drm_dp_mst_branch *mstb = txmsg->dst;
+	int tx_req_type = get_msg_request_type(txmsg->msg[0]);
+	int rx_req_type = get_msg_request_type(rxmsg->msg[0]);
+	char rad_str[64];
+
+	if (tx_req_type == rx_req_type)
+		return true;
+
+	drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, rad_str, sizeof(rad_str));
+	drm_dbg_kms(mgr->dev,
+		    "Got unexpected MST reply, mstb: %p seqno: %d lct: %d rad: %s rx_req_type: %s (%02x) != tx_req_type: %s (%02x)\n",
+		    mstb, hdr->seqno, mstb->lct, rad_str,
+		    drm_dp_mst_req_type_str(rx_req_type), rx_req_type,
+		    drm_dp_mst_req_type_str(tx_req_type), tx_req_type);
+
+	return false;
+}
+
 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 {
 	struct drm_dp_sideband_msg_tx *txmsg;
@@ -3949,9 +3984,9 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 
 	/* find the message */
 	mutex_lock(&mgr->qlock);
+
 	txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
 					 struct drm_dp_sideband_msg_tx, next);
-	mutex_unlock(&mgr->qlock);
 
 	/* Were we actually expecting a response, and from this mstb? */
 	if (!txmsg || txmsg->dst != mstb) {
@@ -3960,6 +3995,15 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 		hdr = &msg->initial_hdr;
 		drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
 			    mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
+
+		mutex_unlock(&mgr->qlock);
+
+		goto out_clear_reply;
+	}
+
+	if (!verify_rx_request_type(mgr, txmsg, msg)) {
+		mutex_unlock(&mgr->qlock);
+
 		goto out_clear_reply;
 	}
 
@@ -3975,20 +4019,15 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 			    txmsg->reply.u.nak.nak_data);
 	}
 
-	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
-	drm_dp_mst_topology_put_mstb(mstb);
-
-	mutex_lock(&mgr->qlock);
 	txmsg->state = DRM_DP_SIDEBAND_TX_RX;
 	list_del(&txmsg->next);
+
 	mutex_unlock(&mgr->qlock);
 
 	wake_up_all(&mgr->tx_waitq);
 
-	return 0;
-
 out_clear_reply:
-	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
+	reset_msg_rx_state(msg);
 out:
 	if (mstb)
 		drm_dp_mst_topology_put_mstb(mstb);
@@ -4070,16 +4109,20 @@ static void drm_dp_mst_up_req_work(struct work_struct *work)
 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
 {
 	struct drm_dp_pending_up_req *up_req;
+	struct drm_dp_mst_branch *mst_primary;
+	int ret = 0;
 
 	if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
-		goto out;
+		goto out_clear_reply;
 
 	if (!mgr->up_req_recv.have_eomt)
 		return 0;
 
 	up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
-	if (!up_req)
-		return -ENOMEM;
+	if (!up_req) {
+		ret = -ENOMEM;
+		goto out_clear_reply;
+	}
 
 	INIT_LIST_HEAD(&up_req->next);
 
@@ -4090,10 +4133,19 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
 		drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
 			    up_req->msg.req_type);
 		kfree(up_req);
-		goto out;
+		goto out_clear_reply;
 	}
 
-	drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
+	mutex_lock(&mgr->lock);
+	mst_primary = mgr->mst_primary;
+	if (!mst_primary || !drm_dp_mst_topology_try_get_mstb(mst_primary)) {
+		mutex_unlock(&mgr->lock);
+		kfree(up_req);
+		goto out_clear_reply;
+	}
+	mutex_unlock(&mgr->lock);
+
+	drm_dp_send_up_ack_reply(mgr, mst_primary, up_req->msg.req_type,
 				 false);
 
 	if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
@@ -4110,13 +4162,13 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
 			    conn_stat->peer_device_type);
 
 		mutex_lock(&mgr->probe_lock);
-		handle_csn = mgr->mst_primary->link_address_sent;
+		handle_csn = mst_primary->link_address_sent;
 		mutex_unlock(&mgr->probe_lock);
 
 		if (!handle_csn) {
 			drm_dbg_kms(mgr->dev, "Got CSN before finish topology probing. Skip it.");
 			kfree(up_req);
-			goto out;
+			goto out_put_primary;
 		}
 	} else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
 		const struct drm_dp_resource_status_notify *res_stat =
@@ -4133,9 +4185,22 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
 	mutex_unlock(&mgr->up_req_lock);
 	queue_work(system_long_wq, &mgr->up_req_work);
 
-out:
-	memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
-	return 0;
+out_put_primary:
+	drm_dp_mst_topology_put_mstb(mst_primary);
+out_clear_reply:
+	reset_msg_rx_state(&mgr->up_req_recv);
+	return ret;
+}
+
+static void update_msg_rx_state(struct drm_dp_mst_topology_mgr *mgr)
+{
+	mutex_lock(&mgr->lock);
+	if (mgr->reset_rx_state) {
+		mgr->reset_rx_state = false;
+		reset_msg_rx_state(&mgr->down_rep_recv);
+		reset_msg_rx_state(&mgr->up_req_recv);
+	}
+	mutex_unlock(&mgr->lock);
 }
 
 /**
@@ -4172,6 +4237,8 @@ int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr, const u
 		*handled = true;
 	}
 
+	update_msg_rx_state(mgr);
+
 	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
 		ret = drm_dp_mst_handle_down_rep(mgr);
 		*handled = true;