July 2024 - Linux-stable-mirror

FAILED: patch "[PATCH] serial: qcom-geni: fix soft lockup on sw flow control and" failed to apply to 6.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.9.y git checkout FETCH_HEAD git cherry-pick -x 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071536-cope-capillary-34c4@gregkh' --subject-prefix 'PATCH 6.9.y' HEAD^.. Possible dependencies: 947cc4ecc06c ("serial: qcom-geni: fix soft lockup on sw flow control and suspend") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:03 +0200 Subject: [PATCH] serial: qcom-geni: fix soft lockup on sw flow control and suspend The stop_tx() callback is used to implement software flow control and must not discard data as the Qualcomm GENI driver is currently doing when there is an active TX command. Cancelling an active command can also leave data in the hardware FIFO, which prevents the watermark interrupt from being enabled when TX is later restarted. This results in a soft lockup and is easily triggered by stopping TX using software flow control in a serial console but this can also happen after suspend. Fix this by only stopping any active command, and effectively clearing the hardware fifo, when shutting down the port. When TX is later restarted, a transfer command may need to be issued to discard any stale data that could prevent the watermark interrupt from firing. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Cc: stable(a)vger.kernel.org # 4.17 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-2-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2bd25afe0d92..a41360d34790 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -649,15 +649,25 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport) static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) { + unsigned char c; u32 irq_en; - if (qcom_geni_serial_main_active(uport) || - !qcom_geni_serial_tx_empty(uport)) - return; + /* + * Start a new transfer in case the previous command was cancelled and + * left data in the FIFO which may prevent the watermark interrupt + * from triggering. Note that the stale data is discarded. + */ + if (!qcom_geni_serial_main_active(uport) && + !qcom_geni_serial_tx_empty(uport)) { + if (uart_fifo_out(uport, &c, 1) == 1) { + writel(M_CMD_DONE_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + qcom_geni_serial_setup_tx(uport, 1); + writel(c, uport->membase + SE_GENI_TX_FIFOn); + } + } irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en |= M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN; - writel(DEF_TX_WM, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); } @@ -665,13 +675,17 @@ static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) { u32 irq_en; - struct qcom_geni_serial_port *port = to_dev_port(uport); irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en &= ~(M_CMD_DONE_EN | M_TX_FIFO_WATERMARK_EN); writel(0, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); - /* Possible stop tx is called multiple times. */ +} + +static void qcom_geni_serial_cancel_tx_cmd(struct uart_port *uport) +{ + struct qcom_geni_serial_port *port = to_dev_port(uport); + if (!qcom_geni_serial_main_active(uport)) return; @@ -684,6 +698,8 @@ static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); } writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + + port->tx_remaining = 0; } static void qcom_geni_serial_handle_rx_fifo(struct uart_port *uport, bool drop) @@ -1069,11 +1085,10 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) { disable_irq(uport->irq); - if (uart_console(uport)) - return; - qcom_geni_serial_stop_tx(uport); qcom_geni_serial_stop_rx(uport); + + qcom_geni_serial_cancel_tx_cmd(uport); } static int qcom_geni_serial_port_setup(struct uart_port *uport)

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix hard lockup on buffer flush" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 507786c51ccf8df726df804ae316a8c52537b407 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071518-alfalfa-identify-0afb@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: 507786c51ccf ("serial: qcom-geni: fix hard lockup on buffer flush") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 507786c51ccf8df726df804ae316a8c52537b407 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:04 +0200 Subject: [PATCH] serial: qcom-geni: fix hard lockup on buffer flush The Qualcomm GENI serial driver does not handle buffer flushing and used to continue printing discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead results in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. This is easily triggered by interrupting a command such as dmesg in a serial console but can also happen when stopping a serial getty on reboot. Implement the flush_buffer() callback and use it to cancel any active TX command when the write buffer has been emptied. Reported-by: Douglas Anderson <dianders(a)chromium.org> Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Cc: stable(a)vger.kernel.org # 5.0 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index a41360d34790..b2bbd2d79dbb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -906,13 +906,17 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, else pending = kfifo_len(&tport->xmit_fifo); - /* All data has been transmitted and acknowledged as received */ - if (!pending && !status && done) { + /* All data has been transmitted or command has been cancelled */ + if (!pending && done) { qcom_geni_serial_stop_tx_fifo(uport); goto out_write_wakeup; } - avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + if (active) + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + else + avail = port->tx_fifo_depth; + avail *= BYTES_PER_FIFO_WORD; chunk = min(avail, pending); @@ -1091,6 +1095,11 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); } +static void qcom_geni_serial_flush_buffer(struct uart_port *uport) +{ + qcom_geni_serial_cancel_tx_cmd(uport); +} + static int qcom_geni_serial_port_setup(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); @@ -1547,6 +1556,7 @@ static const struct uart_ops qcom_geni_console_pops = { .request_port = qcom_geni_serial_request_port, .config_port = qcom_geni_serial_config_port, .shutdown = qcom_geni_serial_shutdown, + .flush_buffer = qcom_geni_serial_flush_buffer, .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl,

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix soft lockup on sw flow control and" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071554-rebel-footsore-1818@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: 947cc4ecc06c ("serial: qcom-geni: fix soft lockup on sw flow control and suspend") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:03 +0200 Subject: [PATCH] serial: qcom-geni: fix soft lockup on sw flow control and suspend The stop_tx() callback is used to implement software flow control and must not discard data as the Qualcomm GENI driver is currently doing when there is an active TX command. Cancelling an active command can also leave data in the hardware FIFO, which prevents the watermark interrupt from being enabled when TX is later restarted. This results in a soft lockup and is easily triggered by stopping TX using software flow control in a serial console but this can also happen after suspend. Fix this by only stopping any active command, and effectively clearing the hardware fifo, when shutting down the port. When TX is later restarted, a transfer command may need to be issued to discard any stale data that could prevent the watermark interrupt from firing. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Cc: stable(a)vger.kernel.org # 4.17 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-2-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2bd25afe0d92..a41360d34790 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -649,15 +649,25 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport) static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) { + unsigned char c; u32 irq_en; - if (qcom_geni_serial_main_active(uport) || - !qcom_geni_serial_tx_empty(uport)) - return; + /* + * Start a new transfer in case the previous command was cancelled and + * left data in the FIFO which may prevent the watermark interrupt + * from triggering. Note that the stale data is discarded. + */ + if (!qcom_geni_serial_main_active(uport) && + !qcom_geni_serial_tx_empty(uport)) { + if (uart_fifo_out(uport, &c, 1) == 1) { + writel(M_CMD_DONE_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + qcom_geni_serial_setup_tx(uport, 1); + writel(c, uport->membase + SE_GENI_TX_FIFOn); + } + } irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en |= M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN; - writel(DEF_TX_WM, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); } @@ -665,13 +675,17 @@ static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) { u32 irq_en; - struct qcom_geni_serial_port *port = to_dev_port(uport); irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en &= ~(M_CMD_DONE_EN | M_TX_FIFO_WATERMARK_EN); writel(0, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); - /* Possible stop tx is called multiple times. */ +} + +static void qcom_geni_serial_cancel_tx_cmd(struct uart_port *uport) +{ + struct qcom_geni_serial_port *port = to_dev_port(uport); + if (!qcom_geni_serial_main_active(uport)) return; @@ -684,6 +698,8 @@ static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); } writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + + port->tx_remaining = 0; } static void qcom_geni_serial_handle_rx_fifo(struct uart_port *uport, bool drop) @@ -1069,11 +1085,10 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) { disable_irq(uport->irq); - if (uart_console(uport)) - return; - qcom_geni_serial_stop_tx(uport); qcom_geni_serial_stop_rx(uport); + + qcom_geni_serial_cancel_tx_cmd(uport); } static int qcom_geni_serial_port_setup(struct uart_port *uport)

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix hard lockup on buffer flush" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 507786c51ccf8df726df804ae316a8c52537b407 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071557-bullion-punk-ee0a@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: 507786c51ccf ("serial: qcom-geni: fix hard lockup on buffer flush") 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") 40ec6d41c841 ("tty: serial: qcom-geni-serial: use of_device_id data") 0626afe57b1f ("tty: serial: qcom-geni-serial: drop the return value from handle_rx") bd7955840cbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()") d420fb491cbc ("tty: serial: qcom-geni-serial: split out the FIFO tx code") fe6a00e8fcbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()") 00ce7c6e86b5 ("tty: serial: qcom-geni-serial: improve the to_dev_port() macro") 6cde11dbf4b6 ("tty: serial: qcom-geni-serial: align #define values") 68c6bd92c86c ("tty: serial: qcom-geni-serial: remove unused symbols") d0fabb0dc1a6 ("tty: serial: qcom-geni-serial: drop unneeded forward definitions") 35781d8356a2 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature") 654a8d6c93e7 ("tty: serial: qcom-geni-serial: Implement start_rx callback") c2194bc999d4 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate.") d6efb3ac3e6c ("Merge tag 'tty-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 507786c51ccf8df726df804ae316a8c52537b407 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:04 +0200 Subject: [PATCH] serial: qcom-geni: fix hard lockup on buffer flush The Qualcomm GENI serial driver does not handle buffer flushing and used to continue printing discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead results in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. This is easily triggered by interrupting a command such as dmesg in a serial console but can also happen when stopping a serial getty on reboot. Implement the flush_buffer() callback and use it to cancel any active TX command when the write buffer has been emptied. Reported-by: Douglas Anderson <dianders(a)chromium.org> Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Cc: stable(a)vger.kernel.org # 5.0 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index a41360d34790..b2bbd2d79dbb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -906,13 +906,17 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, else pending = kfifo_len(&tport->xmit_fifo); - /* All data has been transmitted and acknowledged as received */ - if (!pending && !status && done) { + /* All data has been transmitted or command has been cancelled */ + if (!pending && done) { qcom_geni_serial_stop_tx_fifo(uport); goto out_write_wakeup; } - avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + if (active) + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + else + avail = port->tx_fifo_depth; + avail *= BYTES_PER_FIFO_WORD; chunk = min(avail, pending); @@ -1091,6 +1095,11 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); } +static void qcom_geni_serial_flush_buffer(struct uart_port *uport) +{ + qcom_geni_serial_cancel_tx_cmd(uport); +} + static int qcom_geni_serial_port_setup(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); @@ -1547,6 +1556,7 @@ static const struct uart_ops qcom_geni_console_pops = { .request_port = qcom_geni_serial_request_port, .config_port = qcom_geni_serial_config_port, .shutdown = qcom_geni_serial_shutdown, + .flush_buffer = qcom_geni_serial_flush_buffer, .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl,

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix hard lockup on buffer flush" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 507786c51ccf8df726df804ae316a8c52537b407 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071555-occupy-tables-792a@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: 507786c51ccf ("serial: qcom-geni: fix hard lockup on buffer flush") 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") 40ec6d41c841 ("tty: serial: qcom-geni-serial: use of_device_id data") 0626afe57b1f ("tty: serial: qcom-geni-serial: drop the return value from handle_rx") bd7955840cbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()") d420fb491cbc ("tty: serial: qcom-geni-serial: split out the FIFO tx code") fe6a00e8fcbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()") 00ce7c6e86b5 ("tty: serial: qcom-geni-serial: improve the to_dev_port() macro") 6cde11dbf4b6 ("tty: serial: qcom-geni-serial: align #define values") 68c6bd92c86c ("tty: serial: qcom-geni-serial: remove unused symbols") d0fabb0dc1a6 ("tty: serial: qcom-geni-serial: drop unneeded forward definitions") 35781d8356a2 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature") 654a8d6c93e7 ("tty: serial: qcom-geni-serial: Implement start_rx callback") c2194bc999d4 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate.") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 507786c51ccf8df726df804ae316a8c52537b407 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:04 +0200 Subject: [PATCH] serial: qcom-geni: fix hard lockup on buffer flush The Qualcomm GENI serial driver does not handle buffer flushing and used to continue printing discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead results in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. This is easily triggered by interrupting a command such as dmesg in a serial console but can also happen when stopping a serial getty on reboot. Implement the flush_buffer() callback and use it to cancel any active TX command when the write buffer has been emptied. Reported-by: Douglas Anderson <dianders(a)chromium.org> Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Cc: stable(a)vger.kernel.org # 5.0 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index a41360d34790..b2bbd2d79dbb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -906,13 +906,17 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, else pending = kfifo_len(&tport->xmit_fifo); - /* All data has been transmitted and acknowledged as received */ - if (!pending && !status && done) { + /* All data has been transmitted or command has been cancelled */ + if (!pending && done) { qcom_geni_serial_stop_tx_fifo(uport); goto out_write_wakeup; } - avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + if (active) + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + else + avail = port->tx_fifo_depth; + avail *= BYTES_PER_FIFO_WORD; chunk = min(avail, pending); @@ -1091,6 +1095,11 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); } +static void qcom_geni_serial_flush_buffer(struct uart_port *uport) +{ + qcom_geni_serial_cancel_tx_cmd(uport); +} + static int qcom_geni_serial_port_setup(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); @@ -1547,6 +1556,7 @@ static const struct uart_ops qcom_geni_console_pops = { .request_port = qcom_geni_serial_request_port, .config_port = qcom_geni_serial_config_port, .shutdown = qcom_geni_serial_shutdown, + .flush_buffer = qcom_geni_serial_flush_buffer, .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl,

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix hard lockup on buffer flush" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 507786c51ccf8df726df804ae316a8c52537b407 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071556-cognition-backstab-964b@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: 507786c51ccf ("serial: qcom-geni: fix hard lockup on buffer flush") 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") 40ec6d41c841 ("tty: serial: qcom-geni-serial: use of_device_id data") 0626afe57b1f ("tty: serial: qcom-geni-serial: drop the return value from handle_rx") bd7955840cbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()") d420fb491cbc ("tty: serial: qcom-geni-serial: split out the FIFO tx code") fe6a00e8fcbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()") 00ce7c6e86b5 ("tty: serial: qcom-geni-serial: improve the to_dev_port() macro") 6cde11dbf4b6 ("tty: serial: qcom-geni-serial: align #define values") 68c6bd92c86c ("tty: serial: qcom-geni-serial: remove unused symbols") d0fabb0dc1a6 ("tty: serial: qcom-geni-serial: drop unneeded forward definitions") 35781d8356a2 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature") 654a8d6c93e7 ("tty: serial: qcom-geni-serial: Implement start_rx callback") c2194bc999d4 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate.") d6efb3ac3e6c ("Merge tag 'tty-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 507786c51ccf8df726df804ae316a8c52537b407 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:04 +0200 Subject: [PATCH] serial: qcom-geni: fix hard lockup on buffer flush The Qualcomm GENI serial driver does not handle buffer flushing and used to continue printing discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead results in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. This is easily triggered by interrupting a command such as dmesg in a serial console but can also happen when stopping a serial getty on reboot. Implement the flush_buffer() callback and use it to cancel any active TX command when the write buffer has been emptied. Reported-by: Douglas Anderson <dianders(a)chromium.org> Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Cc: stable(a)vger.kernel.org # 5.0 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index a41360d34790..b2bbd2d79dbb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -906,13 +906,17 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, else pending = kfifo_len(&tport->xmit_fifo); - /* All data has been transmitted and acknowledged as received */ - if (!pending && !status && done) { + /* All data has been transmitted or command has been cancelled */ + if (!pending && done) { qcom_geni_serial_stop_tx_fifo(uport); goto out_write_wakeup; } - avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + if (active) + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + else + avail = port->tx_fifo_depth; + avail *= BYTES_PER_FIFO_WORD; chunk = min(avail, pending); @@ -1091,6 +1095,11 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); } +static void qcom_geni_serial_flush_buffer(struct uart_port *uport) +{ + qcom_geni_serial_cancel_tx_cmd(uport); +} + static int qcom_geni_serial_port_setup(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); @@ -1547,6 +1556,7 @@ static const struct uart_ops qcom_geni_console_pops = { .request_port = qcom_geni_serial_request_port, .config_port = qcom_geni_serial_config_port, .shutdown = qcom_geni_serial_shutdown, + .flush_buffer = qcom_geni_serial_flush_buffer, .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl,

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix hard lockup on buffer flush" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 507786c51ccf8df726df804ae316a8c52537b407 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071554-arrival-handiness-71ea@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: 507786c51ccf ("serial: qcom-geni: fix hard lockup on buffer flush") 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") 40ec6d41c841 ("tty: serial: qcom-geni-serial: use of_device_id data") 0626afe57b1f ("tty: serial: qcom-geni-serial: drop the return value from handle_rx") bd7955840cbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()") d420fb491cbc ("tty: serial: qcom-geni-serial: split out the FIFO tx code") fe6a00e8fcbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()") 00ce7c6e86b5 ("tty: serial: qcom-geni-serial: improve the to_dev_port() macro") 6cde11dbf4b6 ("tty: serial: qcom-geni-serial: align #define values") 68c6bd92c86c ("tty: serial: qcom-geni-serial: remove unused symbols") d0fabb0dc1a6 ("tty: serial: qcom-geni-serial: drop unneeded forward definitions") 35781d8356a2 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature") 654a8d6c93e7 ("tty: serial: qcom-geni-serial: Implement start_rx callback") c2194bc999d4 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate.") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 507786c51ccf8df726df804ae316a8c52537b407 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:04 +0200 Subject: [PATCH] serial: qcom-geni: fix hard lockup on buffer flush The Qualcomm GENI serial driver does not handle buffer flushing and used to continue printing discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead results in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. This is easily triggered by interrupting a command such as dmesg in a serial console but can also happen when stopping a serial getty on reboot. Implement the flush_buffer() callback and use it to cancel any active TX command when the write buffer has been emptied. Reported-by: Douglas Anderson <dianders(a)chromium.org> Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Cc: stable(a)vger.kernel.org # 5.0 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index a41360d34790..b2bbd2d79dbb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -906,13 +906,17 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, else pending = kfifo_len(&tport->xmit_fifo); - /* All data has been transmitted and acknowledged as received */ - if (!pending && !status && done) { + /* All data has been transmitted or command has been cancelled */ + if (!pending && done) { qcom_geni_serial_stop_tx_fifo(uport); goto out_write_wakeup; } - avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + if (active) + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + else + avail = port->tx_fifo_depth; + avail *= BYTES_PER_FIFO_WORD; chunk = min(avail, pending); @@ -1091,6 +1095,11 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); } +static void qcom_geni_serial_flush_buffer(struct uart_port *uport) +{ + qcom_geni_serial_cancel_tx_cmd(uport); +} + static int qcom_geni_serial_port_setup(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); @@ -1547,6 +1556,7 @@ static const struct uart_ops qcom_geni_console_pops = { .request_port = qcom_geni_serial_request_port, .config_port = qcom_geni_serial_config_port, .shutdown = qcom_geni_serial_shutdown, + .flush_buffer = qcom_geni_serial_flush_buffer, .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl,

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix hard lockup on buffer flush" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 507786c51ccf8df726df804ae316a8c52537b407 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071554-plunder-envelope-5c9d@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 507786c51ccf ("serial: qcom-geni: fix hard lockup on buffer flush") 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") 40ec6d41c841 ("tty: serial: qcom-geni-serial: use of_device_id data") 0626afe57b1f ("tty: serial: qcom-geni-serial: drop the return value from handle_rx") bd7955840cbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()") d420fb491cbc ("tty: serial: qcom-geni-serial: split out the FIFO tx code") fe6a00e8fcbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()") 00ce7c6e86b5 ("tty: serial: qcom-geni-serial: improve the to_dev_port() macro") 6cde11dbf4b6 ("tty: serial: qcom-geni-serial: align #define values") 68c6bd92c86c ("tty: serial: qcom-geni-serial: remove unused symbols") d0fabb0dc1a6 ("tty: serial: qcom-geni-serial: drop unneeded forward definitions") 35781d8356a2 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 507786c51ccf8df726df804ae316a8c52537b407 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:04 +0200 Subject: [PATCH] serial: qcom-geni: fix hard lockup on buffer flush The Qualcomm GENI serial driver does not handle buffer flushing and used to continue printing discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead results in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. This is easily triggered by interrupting a command such as dmesg in a serial console but can also happen when stopping a serial getty on reboot. Implement the flush_buffer() callback and use it to cancel any active TX command when the write buffer has been emptied. Reported-by: Douglas Anderson <dianders(a)chromium.org> Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Cc: stable(a)vger.kernel.org # 5.0 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index a41360d34790..b2bbd2d79dbb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -906,13 +906,17 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, else pending = kfifo_len(&tport->xmit_fifo); - /* All data has been transmitted and acknowledged as received */ - if (!pending && !status && done) { + /* All data has been transmitted or command has been cancelled */ + if (!pending && done) { qcom_geni_serial_stop_tx_fifo(uport); goto out_write_wakeup; } - avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + if (active) + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + else + avail = port->tx_fifo_depth; + avail *= BYTES_PER_FIFO_WORD; chunk = min(avail, pending); @@ -1091,6 +1095,11 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); } +static void qcom_geni_serial_flush_buffer(struct uart_port *uport) +{ + qcom_geni_serial_cancel_tx_cmd(uport); +} + static int qcom_geni_serial_port_setup(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); @@ -1547,6 +1556,7 @@ static const struct uart_ops qcom_geni_console_pops = { .request_port = qcom_geni_serial_request_port, .config_port = qcom_geni_serial_config_port, .shutdown = qcom_geni_serial_shutdown, + .flush_buffer = qcom_geni_serial_flush_buffer, .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl,

2 months, 3 weeks

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FAILED: patch "[PATCH] serial: qcom-geni: fix soft lockup on sw flow control and" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071534-designer-distract-6edf@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: 947cc4ecc06c ("serial: qcom-geni: fix soft lockup on sw flow control and suspend") 9aff74cc4e9e ("serial: qcom-geni: fix console shutdown hang") 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") 40ec6d41c841 ("tty: serial: qcom-geni-serial: use of_device_id data") 0626afe57b1f ("tty: serial: qcom-geni-serial: drop the return value from handle_rx") bd7955840cbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()") d420fb491cbc ("tty: serial: qcom-geni-serial: split out the FIFO tx code") fe6a00e8fcbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()") 00ce7c6e86b5 ("tty: serial: qcom-geni-serial: improve the to_dev_port() macro") 6cde11dbf4b6 ("tty: serial: qcom-geni-serial: align #define values") 68c6bd92c86c ("tty: serial: qcom-geni-serial: remove unused symbols") d0fabb0dc1a6 ("tty: serial: qcom-geni-serial: drop unneeded forward definitions") d8aca2f96813 ("tty: serial: qcom-geni-serial: stop operations in progress at shutdown") 35781d8356a2 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature") 654a8d6c93e7 ("tty: serial: qcom-geni-serial: Implement start_rx callback") c2194bc999d4 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate.") d6efb3ac3e6c ("Merge tag 'tty-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:03 +0200 Subject: [PATCH] serial: qcom-geni: fix soft lockup on sw flow control and suspend The stop_tx() callback is used to implement software flow control and must not discard data as the Qualcomm GENI driver is currently doing when there is an active TX command. Cancelling an active command can also leave data in the hardware FIFO, which prevents the watermark interrupt from being enabled when TX is later restarted. This results in a soft lockup and is easily triggered by stopping TX using software flow control in a serial console but this can also happen after suspend. Fix this by only stopping any active command, and effectively clearing the hardware fifo, when shutting down the port. When TX is later restarted, a transfer command may need to be issued to discard any stale data that could prevent the watermark interrupt from firing. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Cc: stable(a)vger.kernel.org # 4.17 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-2-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2bd25afe0d92..a41360d34790 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -649,15 +649,25 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport) static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) { + unsigned char c; u32 irq_en; - if (qcom_geni_serial_main_active(uport) || - !qcom_geni_serial_tx_empty(uport)) - return; + /* + * Start a new transfer in case the previous command was cancelled and + * left data in the FIFO which may prevent the watermark interrupt + * from triggering. Note that the stale data is discarded. + */ + if (!qcom_geni_serial_main_active(uport) && + !qcom_geni_serial_tx_empty(uport)) { + if (uart_fifo_out(uport, &c, 1) == 1) { + writel(M_CMD_DONE_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + qcom_geni_serial_setup_tx(uport, 1); + writel(c, uport->membase + SE_GENI_TX_FIFOn); + } + } irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en |= M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN; - writel(DEF_TX_WM, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); } @@ -665,13 +675,17 @@ static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) { u32 irq_en; - struct qcom_geni_serial_port *port = to_dev_port(uport); irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en &= ~(M_CMD_DONE_EN | M_TX_FIFO_WATERMARK_EN); writel(0, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); - /* Possible stop tx is called multiple times. */ +} + +static void qcom_geni_serial_cancel_tx_cmd(struct uart_port *uport) +{ + struct qcom_geni_serial_port *port = to_dev_port(uport); + if (!qcom_geni_serial_main_active(uport)) return; @@ -684,6 +698,8 @@ static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); } writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + + port->tx_remaining = 0; } static void qcom_geni_serial_handle_rx_fifo(struct uart_port *uport, bool drop) @@ -1069,11 +1085,10 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) { disable_irq(uport->irq); - if (uart_console(uport)) - return; - qcom_geni_serial_stop_tx(uport); qcom_geni_serial_stop_rx(uport); + + qcom_geni_serial_cancel_tx_cmd(uport); } static int qcom_geni_serial_port_setup(struct uart_port *uport)

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FAILED: patch "[PATCH] serial: qcom-geni: fix soft lockup on sw flow control and" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024071533-imply-commute-d073@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: 947cc4ecc06c ("serial: qcom-geni: fix soft lockup on sw flow control and suspend") 9aff74cc4e9e ("serial: qcom-geni: fix console shutdown hang") 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") 40ec6d41c841 ("tty: serial: qcom-geni-serial: use of_device_id data") 0626afe57b1f ("tty: serial: qcom-geni-serial: drop the return value from handle_rx") bd7955840cbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_send_chunk_fifo()") d420fb491cbc ("tty: serial: qcom-geni-serial: split out the FIFO tx code") fe6a00e8fcbe ("tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()") 00ce7c6e86b5 ("tty: serial: qcom-geni-serial: improve the to_dev_port() macro") 6cde11dbf4b6 ("tty: serial: qcom-geni-serial: align #define values") 68c6bd92c86c ("tty: serial: qcom-geni-serial: remove unused symbols") d0fabb0dc1a6 ("tty: serial: qcom-geni-serial: drop unneeded forward definitions") d8aca2f96813 ("tty: serial: qcom-geni-serial: stop operations in progress at shutdown") 35781d8356a2 ("tty: serial: qcom-geni-serial: Add support for Hibernation feature") 654a8d6c93e7 ("tty: serial: qcom-geni-serial: Implement start_rx callback") c2194bc999d4 ("tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate.") d6efb3ac3e6c ("Merge tag 'tty-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan+linaro(a)kernel.org> Date: Thu, 4 Jul 2024 12:18:03 +0200 Subject: [PATCH] serial: qcom-geni: fix soft lockup on sw flow control and suspend The stop_tx() callback is used to implement software flow control and must not discard data as the Qualcomm GENI driver is currently doing when there is an active TX command. Cancelling an active command can also leave data in the hardware FIFO, which prevents the watermark interrupt from being enabled when TX is later restarted. This results in a soft lockup and is easily triggered by stopping TX using software flow control in a serial console but this can also happen after suspend. Fix this by only stopping any active command, and effectively clearing the hardware fifo, when shutting down the port. When TX is later restarted, a transfer command may need to be issued to discard any stale data that could prevent the watermark interrupt from firing. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Cc: stable(a)vger.kernel.org # 4.17 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> Link: https://lore.kernel.org/r/20240704101805.30612-2-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2bd25afe0d92..a41360d34790 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -649,15 +649,25 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport) static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) { + unsigned char c; u32 irq_en; - if (qcom_geni_serial_main_active(uport) || - !qcom_geni_serial_tx_empty(uport)) - return; + /* + * Start a new transfer in case the previous command was cancelled and + * left data in the FIFO which may prevent the watermark interrupt + * from triggering. Note that the stale data is discarded. + */ + if (!qcom_geni_serial_main_active(uport) && + !qcom_geni_serial_tx_empty(uport)) { + if (uart_fifo_out(uport, &c, 1) == 1) { + writel(M_CMD_DONE_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + qcom_geni_serial_setup_tx(uport, 1); + writel(c, uport->membase + SE_GENI_TX_FIFOn); + } + } irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en |= M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN; - writel(DEF_TX_WM, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); } @@ -665,13 +675,17 @@ static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) { u32 irq_en; - struct qcom_geni_serial_port *port = to_dev_port(uport); irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en &= ~(M_CMD_DONE_EN | M_TX_FIFO_WATERMARK_EN); writel(0, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); - /* Possible stop tx is called multiple times. */ +} + +static void qcom_geni_serial_cancel_tx_cmd(struct uart_port *uport) +{ + struct qcom_geni_serial_port *port = to_dev_port(uport); + if (!qcom_geni_serial_main_active(uport)) return; @@ -684,6 +698,8 @@ static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); } writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + + port->tx_remaining = 0; } static void qcom_geni_serial_handle_rx_fifo(struct uart_port *uport, bool drop) @@ -1069,11 +1085,10 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) { disable_irq(uport->irq); - if (uart_console(uport)) - return; - qcom_geni_serial_stop_tx(uport); qcom_geni_serial_stop_rx(uport); + + qcom_geni_serial_cancel_tx_cmd(uport); } static int qcom_geni_serial_port_setup(struct uart_port *uport)

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