From patchwork Thu Dec 13 18:44:41 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 10729591 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 419D03E9D for ; Thu, 13 Dec 2018 18:44:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3406D2C851 for ; Thu, 13 Dec 2018 18:44:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 283512C858; Thu, 13 Dec 2018 18:44:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BFD472C83E for ; Thu, 13 Dec 2018 18:44:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726494AbeLMSot (ORCPT ); Thu, 13 Dec 2018 13:44:49 -0500 Received: from andre.telenet-ops.be ([195.130.132.53]:49212 "EHLO andre.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726437AbeLMSos (ORCPT ); Thu, 13 Dec 2018 13:44:48 -0500 Received: from ramsan ([84.194.111.163]) by andre.telenet-ops.be with bizsmtp id BWkl1z00K3XaVaC01Wklyl; Thu, 13 Dec 2018 19:44:46 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1gXVyX-0007qp-Dt; Thu, 13 Dec 2018 19:44:45 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1gXVyX-0005i7-CR; Thu, 13 Dec 2018 19:44:45 +0100 From: Geert Uytterhoeven To: Greg Kroah-Hartman , Jiri Slaby Cc: Ulrich Hecht , Wolfram Sang , Yoshihiro Shimoda , Yoshinori Sato , linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, linux-serial@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v4 1/4] serial: sh-sci: Fix locking in sci_submit_rx() Date: Thu, 13 Dec 2018 19:44:41 +0100 Message-Id: <20181213184444.21904-2-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181213184444.21904-1-geert+renesas@glider.be> References: <20181213184444.21904-1-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some callers of sci_submit_rx() hold the port spinlock, others don't. During fallback to PIO, the driver needs to obtain the port spinlock. If the lock was already held, spinlock recursion is detected, causing a deadlock: BUG: spinlock recursion on CPU#0. Fix this by adding a flag parameter to sci_submit_rx() for the caller to indicate the port spinlock is already held, so spinlock recursion can be avoided. Move the spin_lock_irqsave() up, so all DMA disable steps are protected, which is safe as the recently introduced dmaengine_terminate_async() can be called in atomic context. Signed-off-by: Geert Uytterhoeven Reviewed-by: Simon Horman --- v4: - No changes, v3: - Split in multiple patches. --- drivers/tty/serial/sh-sci.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 8146d9cef0cbe2d0..2a08039f792235e5 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1331,7 +1331,7 @@ static void sci_tx_dma_release(struct sci_port *s) dma_release_channel(chan); } -static void sci_submit_rx(struct sci_port *s) +static void sci_submit_rx(struct sci_port *s, bool port_lock_held) { struct dma_chan *chan = s->chan_rx; struct uart_port *port = &s->port; @@ -1362,16 +1362,18 @@ static void sci_submit_rx(struct sci_port *s) return; fail: + /* Switch to PIO */ + if (!port_lock_held) + spin_lock_irqsave(&port->lock, flags); if (i) dmaengine_terminate_async(chan); for (i = 0; i < 2; i++) s->cookie_rx[i] = -EINVAL; s->active_rx = -EINVAL; - /* Switch to PIO */ - spin_lock_irqsave(&port->lock, flags); s->chan_rx = NULL; sci_start_rx(port); - spin_unlock_irqrestore(&port->lock, flags); + if (!port_lock_held) + spin_unlock_irqrestore(&port->lock, flags); } static void work_fn_tx(struct work_struct *work) @@ -1491,7 +1493,7 @@ static enum hrtimer_restart rx_timer_fn(struct hrtimer *t) } if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) - sci_submit_rx(s); + sci_submit_rx(s, true); /* Direct new serial port interrupts back to CPU */ scr = serial_port_in(port, SCSCR); @@ -1617,7 +1619,7 @@ static void sci_request_dma(struct uart_port *port) s->chan_rx_saved = s->chan_rx = chan; if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) - sci_submit_rx(s); + sci_submit_rx(s, false); } } @@ -1667,7 +1669,7 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr) scr |= SCSCR_RDRQE; } else { scr &= ~SCSCR_RIE; - sci_submit_rx(s); + sci_submit_rx(s, false); } serial_port_out(port, SCSCR, scr); /* Clear current interrupt */ From patchwork Thu Dec 13 18:44:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 10729583 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A1BEB174F for ; Thu, 13 Dec 2018 18:44:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8CB5E2C83E for ; Thu, 13 Dec 2018 18:44:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 80BC02C855; Thu, 13 Dec 2018 18:44:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 69F0C2C83E for ; Thu, 13 Dec 2018 18:44:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726781AbeLMSos (ORCPT ); Thu, 13 Dec 2018 13:44:48 -0500 Received: from albert.telenet-ops.be ([195.130.137.90]:45564 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726480AbeLMSor (ORCPT ); Thu, 13 Dec 2018 13:44:47 -0500 Received: from ramsan ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id BWkl1z00K3XaVaC06Wklb9; Thu, 13 Dec 2018 19:44:46 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1gXVyX-0007qq-EQ; Thu, 13 Dec 2018 19:44:45 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1gXVyX-0005i9-DI; Thu, 13 Dec 2018 19:44:45 +0100 From: Geert Uytterhoeven To: Greg Kroah-Hartman , Jiri Slaby Cc: Ulrich Hecht , Wolfram Sang , Yoshihiro Shimoda , Yoshinori Sato , linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, linux-serial@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v4 2/4] serial: sh-sci: Fix crash in rx_timer_fn() on PIO fallback Date: Thu, 13 Dec 2018 19:44:42 +0100 Message-Id: <20181213184444.21904-3-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181213184444.21904-1-geert+renesas@glider.be> References: <20181213184444.21904-1-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When falling back to PIO, active_rx must be set to a different value than cookie_rx[i], else sci_dma_rx_find_active() will incorrectly find a match, leading to a NULL pointer dereference in rx_timer_fn() later. Use zero instead, which is the same value as after driver initialization. Signed-off-by: Geert Uytterhoeven Reviewed-by: Simon Horman --- v4: - No changes, v3: - Split in multiple patches. --- drivers/tty/serial/sh-sci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 2a08039f792235e5..e353e03ce2602559 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1369,7 +1369,7 @@ static void sci_submit_rx(struct sci_port *s, bool port_lock_held) dmaengine_terminate_async(chan); for (i = 0; i < 2; i++) s->cookie_rx[i] = -EINVAL; - s->active_rx = -EINVAL; + s->active_rx = 0; s->chan_rx = NULL; sci_start_rx(port); if (!port_lock_held) From patchwork Thu Dec 13 18:44:43 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 10729601 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 363F33E9D for ; Thu, 13 Dec 2018 18:44:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 284CB2C84A for ; Thu, 13 Dec 2018 18:44:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1CEF52C83E; Thu, 13 Dec 2018 18:44:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CE9702C84D for ; Thu, 13 Dec 2018 18:44:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726764AbeLMSos (ORCPT ); Thu, 13 Dec 2018 13:44:48 -0500 Received: from michel.telenet-ops.be ([195.130.137.88]:57182 "EHLO michel.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726630AbeLMSor (ORCPT ); Thu, 13 Dec 2018 13:44:47 -0500 Received: from ramsan ([84.194.111.163]) by michel.telenet-ops.be with bizsmtp id BWkl1z00m3XaVaC06WklEH; Thu, 13 Dec 2018 19:44:46 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1gXVyX-0007qu-F5; Thu, 13 Dec 2018 19:44:45 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1gXVyX-0005iD-Dz; Thu, 13 Dec 2018 19:44:45 +0100 From: Geert Uytterhoeven To: Greg Kroah-Hartman , Jiri Slaby Cc: Ulrich Hecht , Wolfram Sang , Yoshihiro Shimoda , Yoshinori Sato , linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, linux-serial@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v4 3/4] serial: sh-sci: Resume PIO in sci_rx_interrupt() on DMA failure Date: Thu, 13 Dec 2018 19:44:43 +0100 Message-Id: <20181213184444.21904-4-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181213184444.21904-1-geert+renesas@glider.be> References: <20181213184444.21904-1-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On (H)SCIF, sci_submit_rx() is called in the receive interrupt handler. Hence if DMA submission fails, the interrupt handler should resume handling reception using PIO, else no more data is received. Make sci_submit_rx() return an error indicator, so the receive interrupt handler can act appropriately. Signed-off-by: Geert Uytterhoeven Acked-by: Wolfram Sang Reviewed-by: Simon Horman --- v4: - Let sci_submit_rx() return -EAGAIN instead of -1 on failure, - Check for negative error in sci_submit_rx() caller, v3: - Move label handle_pio inside #ifdef to kill defined but not used compiler warning when CONFIG_SERIAL_SH_SCI_DMA=n, - Move the call sci_submit_rx() in sci_rx_interrupt() up, as it may fail, rendering the modification of scr unused, - Split in multiple patches. --- drivers/tty/serial/sh-sci.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index e353e03ce2602559..8df0fd8245203f8b 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1331,7 +1331,7 @@ static void sci_tx_dma_release(struct sci_port *s) dma_release_channel(chan); } -static void sci_submit_rx(struct sci_port *s, bool port_lock_held) +static int sci_submit_rx(struct sci_port *s, bool port_lock_held) { struct dma_chan *chan = s->chan_rx; struct uart_port *port = &s->port; @@ -1359,7 +1359,7 @@ static void sci_submit_rx(struct sci_port *s, bool port_lock_held) s->active_rx = s->cookie_rx[0]; dma_async_issue_pending(chan); - return; + return 0; fail: /* Switch to PIO */ @@ -1374,6 +1374,7 @@ static void sci_submit_rx(struct sci_port *s, bool port_lock_held) sci_start_rx(port); if (!port_lock_held) spin_unlock_irqrestore(&port->lock, flags); + return -EAGAIN; } static void work_fn_tx(struct work_struct *work) @@ -1668,8 +1669,10 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr) disable_irq_nosync(irq); scr |= SCSCR_RDRQE; } else { + if (sci_submit_rx(s, false) < 0) + goto handle_pio; + scr &= ~SCSCR_RIE; - sci_submit_rx(s, false); } serial_port_out(port, SCSCR, scr); /* Clear current interrupt */ @@ -1681,6 +1684,8 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr) return IRQ_HANDLED; } + +handle_pio: #endif if (s->rx_trigger > 1 && s->rx_fifo_timeout > 0) { From patchwork Thu Dec 13 18:44:44 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 10729587 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 07D2A13BF for ; Thu, 13 Dec 2018 18:44:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F020D2C84A for ; Thu, 13 Dec 2018 18:44:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D6B662C858; Thu, 13 Dec 2018 18:44:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 548302C851 for ; Thu, 13 Dec 2018 18:44:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726772AbeLMSos (ORCPT ); Thu, 13 Dec 2018 13:44:48 -0500 Received: from albert.telenet-ops.be ([195.130.137.90]:45566 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726442AbeLMSos (ORCPT ); Thu, 13 Dec 2018 13:44:48 -0500 Received: from ramsan ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id BWkl1z00L3XaVaC06Wklb8; Thu, 13 Dec 2018 19:44:46 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1gXVyX-0007qx-Ft; Thu, 13 Dec 2018 19:44:45 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1gXVyX-0005iG-Ed; Thu, 13 Dec 2018 19:44:45 +0100 From: Geert Uytterhoeven To: Greg Kroah-Hartman , Jiri Slaby Cc: Ulrich Hecht , Wolfram Sang , Yoshihiro Shimoda , Yoshinori Sato , linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, linux-serial@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v4 4/4] serial: sh-sci: Fix fallback to PIO in sci_dma_rx_complete() Date: Thu, 13 Dec 2018 19:44:44 +0100 Message-Id: <20181213184444.21904-5-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181213184444.21904-1-geert+renesas@glider.be> References: <20181213184444.21904-1-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When submitting a DMA request fails in sci_dma_rx_complete(), the driver tries to fall back to PIO, but that does not work: no more data will be received, or the kernel will even crash. Fix this similar as in (but not identical to) sci_submit_rx(): - On SCIF, PIO cannot take over if any DMA transactions are pending, hence they must be terminated first. - All active cookies must be invalidated, else rx_timer_fn() may trigger a NULL pointer dereference. - Restarting the port is not needed, as it is already running, but serial port interrupts must be directed back from the DMA engine to the CPU. Signed-off-by: Geert Uytterhoeven --- v4: - No changes, v3: - Add missing definition of "u16 scr", - Move call to dmaengine_terminate_async() inside the spinlock, for symmetry with sci_submit_rx(), - Split in multiple patches. --- drivers/tty/serial/sh-sci.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 8df0fd8245203f8b..44c29ce3fcc5d894 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1272,6 +1272,8 @@ static void sci_dma_rx_complete(void *arg) struct dma_async_tx_descriptor *desc; unsigned long flags; int active, count = 0; + unsigned int i; + u16 scr; dev_dbg(port->dev, "%s(%d) active cookie %d\n", __func__, port->line, s->active_rx); @@ -1313,8 +1315,18 @@ static void sci_dma_rx_complete(void *arg) dev_warn(port->dev, "Failed submitting Rx DMA descriptor\n"); /* Switch to PIO */ spin_lock_irqsave(&port->lock, flags); + dmaengine_terminate_async(chan); + for (i = 0; i < 2; i++) + s->cookie_rx[i] = -EINVAL; + s->active_rx = 0; s->chan_rx = NULL; - sci_start_rx(port); + /* Direct new serial port interrupts back to CPU */ + scr = serial_port_in(port, SCSCR); + if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) { + scr &= ~SCSCR_RDRQE; + enable_irq(s->irqs[SCIx_RXI_IRQ]); + } + serial_port_out(port, SCSCR, scr | SCSCR_RIE); spin_unlock_irqrestore(&port->lock, flags); }