From 0bfd464d3fdd5bb322f9cace4cc47f1796545cf7 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 9 Jan 2016 21:13:44 -0800 Subject: tty: Wait interruptibly for tty lock on reopen Allow a signal to interrupt the wait for a tty reopen; eg., if the tty has starting final close and is waiting for the device to drain. Signed-off-by: Peter Hurley Cc: stable # 4.4 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 8 +++++++- drivers/tty/tty_mutex.c | 8 ++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) (limited to 'drivers/tty') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 892c92354745..765935b144d6 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2065,7 +2065,12 @@ retry_open: if (tty) { mutex_unlock(&tty_mutex); - tty_lock(tty); + retval = tty_lock_interruptible(tty); + if (retval) { + if (retval == -EINTR) + retval = -ERESTARTSYS; + goto err_unref; + } /* safe to drop the kref from tty_driver_lookup_tty() */ tty_kref_put(tty); retval = tty_reopen(tty); @@ -2152,6 +2157,7 @@ retry_open: return 0; err_unlock: mutex_unlock(&tty_mutex); +err_unref: /* after locks to avoid deadlock */ if (!IS_ERR_OR_NULL(driver)) tty_driver_kref_put(driver); diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 77703a391207..d2f3c4cd697f 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -19,6 +19,14 @@ void __lockfunc tty_lock(struct tty_struct *tty) } EXPORT_SYMBOL(tty_lock); +int tty_lock_interruptible(struct tty_struct *tty) +{ + if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty)) + return -EIO; + tty_kref_get(tty); + return mutex_lock_interruptible(&tty->legacy_mutex); +} + void __lockfunc tty_unlock(struct tty_struct *tty) { if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty)) -- cgit v1.2.3 From 7f22f6c935cda600660e623a411fe380015d28d9 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 9 Jan 2016 21:13:45 -0800 Subject: tty: Retry failed reopen if tty teardown in-progress A small window exists where a tty reopen will observe the tty just prior to imminent teardown (tty->count == 0); in this case, open() returns EIO to userspace. Instead, retry the open after checking for signals and yielding; this interruptible retry loop allows teardown to commence and initialize a new tty on retry. Never retry the BSD master pty reopen; there is no guarantee the pty pair teardown is imminent since the slave file descriptors may remain open indefinitely. Signed-off-by: Peter Hurley Cc: stable # 4.4 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 765935b144d6..a1b36bf545e8 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1463,13 +1463,13 @@ static int tty_reopen(struct tty_struct *tty) { struct tty_driver *driver = tty->driver; - if (!tty->count) - return -EIO; - if (driver->type == TTY_DRIVER_TYPE_PTY && driver->subtype == PTY_TYPE_MASTER) return -EIO; + if (!tty->count) + return -EAGAIN; + if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) return -EBUSY; @@ -2088,7 +2088,11 @@ retry_open: if (IS_ERR(tty)) { retval = PTR_ERR(tty); - goto err_file; + if (retval != -EAGAIN || signal_pending(current)) + goto err_file; + tty_free_file(filp); + schedule(); + goto retry_open; } tty_add_file(tty, filp); -- cgit v1.2.3 From 5c17c861a357e9458001f021a7afa7aab9937439 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 10 Jan 2016 22:40:55 -0800 Subject: tty: Fix unsafe ldisc reference via ioctl(TIOCGETD) ioctl(TIOCGETD) retrieves the line discipline id directly from the ldisc because the line discipline id (c_line) in termios is untrustworthy; userspace may have set termios via ioctl(TCSETS*) without actually changing the line discipline via ioctl(TIOCSETD). However, directly accessing the current ldisc via tty->ldisc is unsafe; the ldisc ptr dereferenced may be stale if the line discipline is changing via ioctl(TIOCSETD) or hangup. Wait for the line discipline reference (just like read() or write()) to retrieve the "current" line discipline id. Cc: Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'drivers/tty') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index a1b36bf545e8..5cec01c75691 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2658,6 +2658,28 @@ static int tiocsetd(struct tty_struct *tty, int __user *p) return ret; } +/** + * tiocgetd - get line discipline + * @tty: tty device + * @p: pointer to user data + * + * Retrieves the line discipline id directly from the ldisc. + * + * Locking: waits for ldisc reference (in case the line discipline + * is changing or the tty is being hungup) + */ + +static int tiocgetd(struct tty_struct *tty, int __user *p) +{ + struct tty_ldisc *ld; + int ret; + + ld = tty_ldisc_ref_wait(tty); + ret = put_user(ld->ops->num, p); + tty_ldisc_deref(ld); + return ret; +} + /** * send_break - performed time break * @tty: device to break on @@ -2884,7 +2906,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case TIOCGSID: return tiocgsid(tty, real_tty, p); case TIOCGETD: - return put_user(tty->ldisc->ops->num, (int __user *)p); + return tiocgetd(tty, p); case TIOCSETD: return tiocsetd(tty, p); case TIOCVHANGUP: -- cgit v1.2.3 From 6d27a63caad3f13e96cf065d2d96828c2006be6b Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 10 Jan 2016 22:40:56 -0800 Subject: n_tty: Fix unsafe reference to "other" ldisc Although n_tty_check_unthrottle() has a valid ldisc reference (since the tty core gets the ldisc ref in tty_read() before calling the line discipline read() method), it does not have a valid ldisc reference to the "other" pty of a pty pair. Since getting an ldisc reference for tty->link essentially open-codes tty_wakeup(), just replace with the equivalent tty_wakeup(). Cc: Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_tty.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index d9a5fc28fef4..b280abaad91b 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -269,16 +269,13 @@ static void n_tty_check_throttle(struct tty_struct *tty) static void n_tty_check_unthrottle(struct tty_struct *tty) { - if (tty->driver->type == TTY_DRIVER_TYPE_PTY && - tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) { + if (tty->driver->type == TTY_DRIVER_TYPE_PTY) { if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) return; if (!tty->count) return; n_tty_kick_worker(tty); - n_tty_write_wakeup(tty->link); - if (waitqueue_active(&tty->link->write_wait)) - wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); + tty_wakeup(tty->link); return; } -- cgit v1.2.3 From 6c55d9b98335f7f6bd5f061866ff1633401f3a44 Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Fri, 29 Jan 2016 16:49:47 +0200 Subject: serial: 8250_pci: Add Intel Broadwell ports Some recent (early 2015) macbooks have Intel Broadwell where LPSS UARTs are PCI enumerated instead of ACPI. The LPSS UART block is pretty much same as used on Intel Baytrail so we can reuse the existing Baytrail setup code. Add both Broadwell LPSS UART ports to the list of supported devices. Signed-off-by: Leif Liddy Signed-off-by: Mika Westerberg Reviewed-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index 4097f3f65b3b..e71ec78fc11e 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1379,6 +1379,9 @@ ce4100_serial_setup(struct serial_private *priv, #define PCI_DEVICE_ID_INTEL_BSW_UART1 0x228a #define PCI_DEVICE_ID_INTEL_BSW_UART2 0x228c +#define PCI_DEVICE_ID_INTEL_BDW_UART1 0x9ce3 +#define PCI_DEVICE_ID_INTEL_BDW_UART2 0x9ce4 + #define BYT_PRV_CLK 0x800 #define BYT_PRV_CLK_EN (1 << 0) #define BYT_PRV_CLK_M_VAL_SHIFT 1 @@ -1461,11 +1464,13 @@ byt_serial_setup(struct serial_private *priv, switch (pdev->device) { case PCI_DEVICE_ID_INTEL_BYT_UART1: case PCI_DEVICE_ID_INTEL_BSW_UART1: + case PCI_DEVICE_ID_INTEL_BDW_UART1: rx_param->src_id = 3; tx_param->dst_id = 2; break; case PCI_DEVICE_ID_INTEL_BYT_UART2: case PCI_DEVICE_ID_INTEL_BSW_UART2: + case PCI_DEVICE_ID_INTEL_BDW_UART2: rx_param->src_id = 5; tx_param->dst_id = 4; break; @@ -2062,6 +2067,20 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = { .subdevice = PCI_ANY_ID, .setup = byt_serial_setup, }, + { + .vendor = PCI_VENDOR_ID_INTEL, + .device = PCI_DEVICE_ID_INTEL_BDW_UART1, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .setup = byt_serial_setup, + }, + { + .vendor = PCI_VENDOR_ID_INTEL, + .device = PCI_DEVICE_ID_INTEL_BDW_UART2, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .setup = byt_serial_setup, + }, /* * ITE */ @@ -5506,6 +5525,16 @@ static struct pci_device_id serial_pci_tbl[] = { PCI_CLASS_COMMUNICATION_SERIAL << 8, 0xff0000, pbn_byt }, + /* Intel Broadwell */ + { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BDW_UART1, + PCI_ANY_ID, PCI_ANY_ID, + PCI_CLASS_COMMUNICATION_SERIAL << 8, 0xff0000, + pbn_byt }, + { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BDW_UART2, + PCI_ANY_ID, PCI_ANY_ID, + PCI_CLASS_COMMUNICATION_SERIAL << 8, 0xff0000, + pbn_byt }, + /* * Intel Quark x1000 */ -- cgit v1.2.3