From f4353daf4905c0099fd25fa742e2ffd4a4bab26a Mon Sep 17 00:00:00 2001 From: Andri Yngvason Date: Wed, 14 Mar 2018 11:52:56 +0000 Subject: can: cc770: Fix stalls on rt-linux, remove redundant IRQ ack This has been reported to cause stalls on rt-linux. Suggested-by: Richard Weinberger Tested-by: Richard Weinberger Signed-off-by: Andri Yngvason Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/cc770/cc770.c | 15 --------------- 1 file changed, 15 deletions(-) (limited to 'drivers/net/can/cc770/cc770.c') diff --git a/drivers/net/can/cc770/cc770.c b/drivers/net/can/cc770/cc770.c index 1e37313054f3..9fed163262e0 100644 --- a/drivers/net/can/cc770/cc770.c +++ b/drivers/net/can/cc770/cc770.c @@ -447,15 +447,6 @@ static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev) stats->tx_bytes += dlc; - - /* - * HM: We had some cases of repeated IRQs so make sure the - * INT is acknowledged I know it's already further up, but - * doing again fixed the issue - */ - cc770_write_reg(priv, msgobj[mo].ctrl0, - MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES); - return NETDEV_TX_OK; } @@ -684,12 +675,6 @@ static void cc770_tx_interrupt(struct net_device *dev, unsigned int o) /* Nothing more to send, switch off interrupts */ cc770_write_reg(priv, msgobj[mo].ctrl0, MSGVAL_RES | TXIE_RES | RXIE_RES | INTPND_RES); - /* - * We had some cases of repeated IRQ so make sure the - * INT is acknowledged - */ - cc770_write_reg(priv, msgobj[mo].ctrl0, - MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES); stats->tx_packets++; can_get_echo_skb(dev, 0); -- cgit v1.2.3-58-ga151 From 746201235b3f876792099079f4c6fea941d76183 Mon Sep 17 00:00:00 2001 From: Andri Yngvason Date: Wed, 14 Mar 2018 11:52:57 +0000 Subject: can: cc770: Fix queue stall & dropped RTR reply While waiting for the TX object to send an RTR, an external message with a matching id can overwrite the TX data. In this case we must call the rx routine and then try transmitting the message that was overwritten again. The queue was being stalled because the RX event did not generate an interrupt to wake up the queue again and the TX event did not happen because the TXRQST flag is reset by the chip when new data is received. According to the CC770 datasheet the id of a message object should not be changed while the MSGVAL bit is set. This has been fixed by resetting the MSGVAL bit before modifying the object in the transmit function and setting it after. It is not enough to set & reset CPUUPD. It is important to keep the MSGVAL bit reset while the message object is being modified. Otherwise, during RTR transmission, a frame with matching id could trigger an rx-interrupt, which would cause a race condition between the interrupt routine and the transmit function. Signed-off-by: Andri Yngvason Tested-by: Richard Weinberger Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/cc770/cc770.c | 94 ++++++++++++++++++++++++++++++------------- drivers/net/can/cc770/cc770.h | 2 + 2 files changed, 68 insertions(+), 28 deletions(-) (limited to 'drivers/net/can/cc770/cc770.c') diff --git a/drivers/net/can/cc770/cc770.c b/drivers/net/can/cc770/cc770.c index 9fed163262e0..2743d82d4424 100644 --- a/drivers/net/can/cc770/cc770.c +++ b/drivers/net/can/cc770/cc770.c @@ -390,37 +390,23 @@ static int cc770_get_berr_counter(const struct net_device *dev, return 0; } -static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev) +static void cc770_tx(struct net_device *dev, int mo) { struct cc770_priv *priv = netdev_priv(dev); - struct net_device_stats *stats = &dev->stats; - struct can_frame *cf = (struct can_frame *)skb->data; - unsigned int mo = obj2msgobj(CC770_OBJ_TX); + struct can_frame *cf = (struct can_frame *)priv->tx_skb->data; u8 dlc, rtr; u32 id; int i; - if (can_dropped_invalid_skb(dev, skb)) - return NETDEV_TX_OK; - - if ((cc770_read_reg(priv, - msgobj[mo].ctrl1) & TXRQST_UNC) == TXRQST_SET) { - netdev_err(dev, "TX register is still occupied!\n"); - return NETDEV_TX_BUSY; - } - - netif_stop_queue(dev); - dlc = cf->can_dlc; id = cf->can_id; - if (cf->can_id & CAN_RTR_FLAG) - rtr = 0; - else - rtr = MSGCFG_DIR; + rtr = cf->can_id & CAN_RTR_FLAG ? 0 : MSGCFG_DIR; + + cc770_write_reg(priv, msgobj[mo].ctrl0, + MSGVAL_RES | TXIE_RES | RXIE_RES | INTPND_RES); cc770_write_reg(priv, msgobj[mo].ctrl1, RMTPND_RES | TXRQST_RES | CPUUPD_SET | NEWDAT_RES); - cc770_write_reg(priv, msgobj[mo].ctrl0, - MSGVAL_SET | TXIE_SET | RXIE_RES | INTPND_RES); + if (id & CAN_EFF_FLAG) { id &= CAN_EFF_MASK; cc770_write_reg(priv, msgobj[mo].config, @@ -439,13 +425,30 @@ static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev) for (i = 0; i < dlc; i++) cc770_write_reg(priv, msgobj[mo].data[i], cf->data[i]); - /* Store echo skb before starting the transfer */ - can_put_echo_skb(skb, dev, 0); - cc770_write_reg(priv, msgobj[mo].ctrl1, - RMTPND_RES | TXRQST_SET | CPUUPD_RES | NEWDAT_UNC); + RMTPND_UNC | TXRQST_SET | CPUUPD_RES | NEWDAT_UNC); + cc770_write_reg(priv, msgobj[mo].ctrl0, + MSGVAL_SET | TXIE_SET | RXIE_SET | INTPND_UNC); +} + +static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct cc770_priv *priv = netdev_priv(dev); + unsigned int mo = obj2msgobj(CC770_OBJ_TX); + + if (can_dropped_invalid_skb(dev, skb)) + return NETDEV_TX_OK; - stats->tx_bytes += dlc; + netif_stop_queue(dev); + + if ((cc770_read_reg(priv, + msgobj[mo].ctrl1) & TXRQST_UNC) == TXRQST_SET) { + netdev_err(dev, "TX register is still occupied!\n"); + return NETDEV_TX_BUSY; + } + + priv->tx_skb = skb; + cc770_tx(dev, mo); return NETDEV_TX_OK; } @@ -671,13 +674,47 @@ static void cc770_tx_interrupt(struct net_device *dev, unsigned int o) struct cc770_priv *priv = netdev_priv(dev); struct net_device_stats *stats = &dev->stats; unsigned int mo = obj2msgobj(o); + struct can_frame *cf; + u8 ctrl1; + + ctrl1 = cc770_read_reg(priv, msgobj[mo].ctrl1); - /* Nothing more to send, switch off interrupts */ cc770_write_reg(priv, msgobj[mo].ctrl0, MSGVAL_RES | TXIE_RES | RXIE_RES | INTPND_RES); + cc770_write_reg(priv, msgobj[mo].ctrl1, + RMTPND_RES | TXRQST_RES | MSGLST_RES | NEWDAT_RES); - stats->tx_packets++; + if (unlikely(!priv->tx_skb)) { + netdev_err(dev, "missing tx skb in tx interrupt\n"); + return; + } + + if (unlikely(ctrl1 & MSGLST_SET)) { + stats->rx_over_errors++; + stats->rx_errors++; + } + + /* When the CC770 is sending an RTR message and it receives a regular + * message that matches the id of the RTR message, it will overwrite the + * outgoing message in the TX register. When this happens we must + * process the received message and try to transmit the outgoing skb + * again. + */ + if (unlikely(ctrl1 & NEWDAT_SET)) { + cc770_rx(dev, mo, ctrl1); + cc770_tx(dev, mo); + return; + } + + can_put_echo_skb(priv->tx_skb, dev, 0); can_get_echo_skb(dev, 0); + + cf = (struct can_frame *)priv->tx_skb->data; + stats->tx_bytes += cf->can_dlc; + stats->tx_packets++; + + priv->tx_skb = NULL; + netif_wake_queue(dev); } @@ -789,6 +826,7 @@ struct net_device *alloc_cc770dev(int sizeof_priv) priv->can.do_set_bittiming = cc770_set_bittiming; priv->can.do_set_mode = cc770_set_mode; priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES; + priv->tx_skb = NULL; memcpy(priv->obj_flags, cc770_obj_flags, sizeof(cc770_obj_flags)); diff --git a/drivers/net/can/cc770/cc770.h b/drivers/net/can/cc770/cc770.h index a1739db98d91..95752e1d1283 100644 --- a/drivers/net/can/cc770/cc770.h +++ b/drivers/net/can/cc770/cc770.h @@ -193,6 +193,8 @@ struct cc770_priv { u8 cpu_interface; /* CPU interface register */ u8 clkout; /* Clock out register */ u8 bus_config; /* Bus conffiguration register */ + + struct sk_buff *tx_skb; }; struct net_device *alloc_cc770dev(int sizeof_priv); -- cgit v1.2.3-58-ga151 From 9ffd7503944ec7c0ef41c3245d1306c221aef2be Mon Sep 17 00:00:00 2001 From: Andri Yngvason Date: Thu, 15 Mar 2018 18:23:17 +0000 Subject: can: cc770: Fix use after free in cc770_tx_interrupt() This fixes use after free introduced by the last cc770 patch. Signed-off-by: Andri Yngvason Fixes: 746201235b3f ("can: cc770: Fix queue stall & dropped RTR reply") Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/cc770/cc770.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers/net/can/cc770/cc770.c') diff --git a/drivers/net/can/cc770/cc770.c b/drivers/net/can/cc770/cc770.c index 2743d82d4424..6da69af103e6 100644 --- a/drivers/net/can/cc770/cc770.c +++ b/drivers/net/can/cc770/cc770.c @@ -706,13 +706,12 @@ static void cc770_tx_interrupt(struct net_device *dev, unsigned int o) return; } - can_put_echo_skb(priv->tx_skb, dev, 0); - can_get_echo_skb(dev, 0); - cf = (struct can_frame *)priv->tx_skb->data; stats->tx_bytes += cf->can_dlc; stats->tx_packets++; + can_put_echo_skb(priv->tx_skb, dev, 0); + can_get_echo_skb(dev, 0); priv->tx_skb = NULL; netif_wake_queue(dev); -- cgit v1.2.3-58-ga151