From 3bfd1300abfe3adb18e84a89d97a0e82a22124bb Mon Sep 17 00:00:00 2001 From: Matt Wilson Date: Mon, 13 Nov 2017 11:31:31 -0800 Subject: [PATCH 1/7] serial: 8250_pci: Add Amazon PCI serial device ID This device will be used in future Amazon EC2 instances as the primary serial port (i.e., data sent to this port will be available via the GetConsoleOuput [1] EC2 API). [1] http://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_GetConsoleOutput.html Cc: stable Signed-off-by: Matt Wilson Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index b7e0e3416641..54adf8d56350 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -5135,6 +5135,9 @@ static const struct pci_device_id serial_pci_tbl[] = { { PCI_DEVICE(0x1601, 0x0800), .driver_data = pbn_b0_4_1250000 }, { PCI_DEVICE(0x1601, 0xa801), .driver_data = pbn_b0_4_1250000 }, + /* Amazon PCI serial device */ + { PCI_DEVICE(0x1d0f, 0x8250), .driver_data = pbn_b0_1_115200 }, + /* * These entries match devices with class COMMUNICATION_SERIAL, * COMMUNICATION_MODEM or COMMUNICATION_MULTISERIAL From 0ff3ab701963a845d52337ded7eebf2d1a14fe00 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Wed, 22 Nov 2017 09:57:28 +0000 Subject: [PATCH 2/7] serial: 8250_early: Only set divisor if valid clk & baud If either uartclk or baud are 0, avoid calculating and setting a divisor based on them since the output will almost certainly be garbage. This also allows platforms such as the MIPS generic kernel, which has no way to know a valid BASE_BASE for the board it is actually booted on at compile time, to set BASE_BAUD to 0 and avoid early_8250 setting a bad divisor. This fixes a regression caused by commit 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure"), which changed the behavior of of_setup_earlycon such that it sets a baud rate in the earlycon structure where previously it was left as 0. All boards supported by the MIPS generic kernel started outputting garbage from the boot console due to an incorrect divisor being set. Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") Cc: stable # 4.14 Signed-off-by: Matt Redfearn Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_early.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c index 362c25ff188a..ae6a256524d8 100644 --- a/drivers/tty/serial/8250/8250_early.c +++ b/drivers/tty/serial/8250/8250_early.c @@ -122,12 +122,14 @@ static void __init init_port(struct earlycon_device *device) serial8250_early_out(port, UART_FCR, 0); /* no fifo */ serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */ - divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud); - c = serial8250_early_in(port, UART_LCR); - serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB); - serial8250_early_out(port, UART_DLL, divisor & 0xff); - serial8250_early_out(port, UART_DLM, (divisor >> 8) & 0xff); - serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB); + if (port->uartclk && device->baud) { + divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud); + c = serial8250_early_in(port, UART_LCR); + serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB); + serial8250_early_out(port, UART_DLL, divisor & 0xff); + serial8250_early_out(port, UART_DLM, (divisor >> 8) & 0xff); + serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB); + } } int __init early_serial8250_setup(struct earlycon_device *device, From eb281683621b71ab9710d9dccbbef0c2e1769c97 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 3 Nov 2017 15:30:52 +0100 Subject: [PATCH 3/7] serdev: ttyport: add missing receive_buf sanity checks The receive_buf tty-port callback should return the number of bytes accepted and must specifically never return a negative errno (or a value larger than the buffer size) to the tty layer. A serdev driver not providing a receive_buf callback would currently cause the flush_to_ldisc() worker to spin in a tight loop when the tty buffer pointers are incremented with -EINVAL (-22) after data has been received. A serdev driver occasionally returning a negative errno (or a too large byte count) could cause information leaks or crashes when accessing memory outside the tty buffers in consecutive callbacks. Fixes: cd6484e1830b ("serdev: Introduce new bus for serial attached devices") Cc: stable # 4.11 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serdev/serdev-ttyport.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c index ce7ad0acee7a..09fbdd52a561 100644 --- a/drivers/tty/serdev/serdev-ttyport.c +++ b/drivers/tty/serdev/serdev-ttyport.c @@ -27,11 +27,22 @@ static int ttyport_receive_buf(struct tty_port *port, const unsigned char *cp, { struct serdev_controller *ctrl = port->client_data; struct serport *serport = serdev_controller_get_drvdata(ctrl); + int ret; if (!test_bit(SERPORT_ACTIVE, &serport->flags)) return 0; - return serdev_controller_receive_buf(ctrl, cp, count); + ret = serdev_controller_receive_buf(ctrl, cp, count); + + dev_WARN_ONCE(&ctrl->dev, ret < 0 || ret > count, + "receive_buf returns %d (count = %zu)\n", + ret, count); + if (ret < 0) + return 0; + else if (ret > count) + return count; + + return ret; } static void ttyport_write_wakeup(struct tty_port *port) From fd00cf81a9a84776ba58e56bd042c726dcf75cf3 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 3 Nov 2017 15:30:53 +0100 Subject: [PATCH 4/7] serdev: fix receive_buf return value when no callback The receive_buf callback is supposed to return the number of bytes processed and should specifically not return a negative errno. Due to missing sanity checks in the serdev tty-port controller, a driver not providing a receive_buf callback could cause the flush_to_ldisc() worker to spin in a tight loop when the tty buffer pointers are incremented with -EINVAL (-22). The missing sanity checks have now been added to the tty-port controller, but let's fix up the serdev-controller helper as well. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- include/linux/serdev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/serdev.h b/include/linux/serdev.h index e69402d4a8ae..d609e6dc5bad 100644 --- a/include/linux/serdev.h +++ b/include/linux/serdev.h @@ -184,7 +184,7 @@ static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl, struct serdev_device *serdev = ctrl->serdev; if (!serdev || !serdev->ops->receive_buf) - return -EINVAL; + return 0; return serdev->ops->receive_buf(serdev, data, count); } From 8bcd4e6a8decac251d55c4377e2e67f052777ce0 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 3 Nov 2017 15:30:55 +0100 Subject: [PATCH 5/7] serdev: ttyport: fix NULL-deref on hangup Make sure to use a properly refcounted tty_struct in write_wake up to avoid dereferencing a NULL-pointer when a port is being hung up. Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver") Cc: stable # 4.11 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serdev/serdev-ttyport.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c index 09fbdd52a561..12cb9139073e 100644 --- a/drivers/tty/serdev/serdev-ttyport.c +++ b/drivers/tty/serdev/serdev-ttyport.c @@ -49,12 +49,19 @@ static void ttyport_write_wakeup(struct tty_port *port) { struct serdev_controller *ctrl = port->client_data; struct serport *serport = serdev_controller_get_drvdata(ctrl); + struct tty_struct *tty; - if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags) && + tty = tty_port_tty_get(port); + if (!tty) + return; + + if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) && test_bit(SERPORT_ACTIVE, &serport->flags)) serdev_controller_write_wakeup(ctrl); - wake_up_interruptible_poll(&port->tty->write_wait, POLLOUT); + wake_up_interruptible_poll(&tty->write_wait, POLLOUT); + + tty_kref_put(tty); } static const struct tty_port_client_operations client_ops = { From 90dbad8cd6efccbdce109d5ef0724f8434a6cdde Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 3 Nov 2017 15:30:56 +0100 Subject: [PATCH 6/7] serdev: ttyport: fix tty locking in close Make sure to hold the tty lock as required when calling tty-driver close() (e.g. to avoid racing with hangup()). Note that the serport active flag is currently set under the lock at controller open, but really isn't protected by it. Fixes: cd6484e1830b ("serdev: Introduce new bus for serial attached devices") Signed-off-by: Johan Hovold Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serdev/serdev-ttyport.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c index 12cb9139073e..247788a16f0b 100644 --- a/drivers/tty/serdev/serdev-ttyport.c +++ b/drivers/tty/serdev/serdev-ttyport.c @@ -154,8 +154,10 @@ static void ttyport_close(struct serdev_controller *ctrl) clear_bit(SERPORT_ACTIVE, &serport->flags); + tty_lock(tty); if (tty->ops->close) tty->ops->close(tty, NULL); + tty_unlock(tty); tty_release_struct(tty, serport->tty_idx); } From c8ec2041f549e7f2dee0c34d25381be6f7805f99 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Tue, 28 Nov 2017 15:22:20 +0000 Subject: [PATCH 7/7] MIPS: Add custom serial.h with BASE_BAUD override for generic kernel Add a custom serial.h header for MIPS, allowing platforms to override the asm-generic version if required. The generic platform uses this header to set BASE_BAUD to 0. The generic platform supports multiple boards, which may have different UART clocks. Also one of the boards supported is the Boston FPGA board, where the UART clock depends on the loaded FPGA bitfile. As such there is no way that the generic kernel can set a compile time default BASE_BAUD. Commit 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") changed the behavior of of_setup_earlycon such that any baud rate set in the device tree is now set in the earlycon structure. The UART driver will then calculate a divisor based on BASE_BAUD and set it. With MIPS generic kernels this resulted in garbage output due to the incorrect uart clock rate being used to calculate a divisor. This commit, combined with "serial: 8250_early: Only set divisor if valid clk & baud" prevents the earlycon code setting a bad divisor and restores earlycon output. Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") Cc: stable # 4.14 Signed-off-by: Matt Redfearn Signed-off-by: Greg Kroah-Hartman --- arch/mips/include/asm/Kbuild | 1 - arch/mips/include/asm/serial.h | 22 ++++++++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-) create mode 100644 arch/mips/include/asm/serial.h diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild index 7c8aab23bce8..b1f66699677d 100644 --- a/arch/mips/include/asm/Kbuild +++ b/arch/mips/include/asm/Kbuild @@ -16,7 +16,6 @@ generic-y += qrwlock.h generic-y += qspinlock.h generic-y += sections.h generic-y += segment.h -generic-y += serial.h generic-y += trace_clock.h generic-y += unaligned.h generic-y += user.h diff --git a/arch/mips/include/asm/serial.h b/arch/mips/include/asm/serial.h new file mode 100644 index 000000000000..1d830c6666c2 --- /dev/null +++ b/arch/mips/include/asm/serial.h @@ -0,0 +1,22 @@ +/* + * Copyright (C) 2017 MIPS Tech, LLC + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ +#ifndef __ASM__SERIAL_H +#define __ASM__SERIAL_H + +#ifdef CONFIG_MIPS_GENERIC +/* + * Generic kernels cannot know a correct value for all platforms at + * compile time. Set it to 0 to prevent 8250_early using it + */ +#define BASE_BAUD 0 +#else +#include +#endif + +#endif /* __ASM__SERIAL_H */