linux-stable.git/drivers/tty, branch v4.4.18

devpts: clean up interface to pty drivers

2016-08-16T07:30:49+00:00

commit 67245ff332064c01b760afa7a384ccda024bfd24 upstream.

This gets rid of the horrible notion of having that

    struct inode *ptmx_inode

be the linchpin of the interface between the pty code and devpts.

By de-emphasizing the ptmx inode, a lot of things actually get cleaner,
and we will have a much saner way forward.  In particular, this will
allow us to associate with any particular devpts instance at open-time,
and not be artificially tied to one particular ptmx inode.

The patch itself is actually fairly straightforward, and apart from some
locking and return path cleanups it's pretty mechanical:

 - the interfaces that devpts exposes all take "struct pts_fs_info *"
   instead of "struct inode *ptmx_inode" now.

   NOTE! The "struct pts_fs_info" thing is a completely opaque structure
   as far as the pty driver is concerned: it's still declared entirely
   internally to devpts. So the pty code can't actually access it in any
   way, just pass it as a "cookie" to the devpts code.

 - the "look up the pts fs info" is now a single clear operation, that
   also does the reference count increment on the pts superblock.

   So "devpts_add/del_ref()" is gone, and replaced by a "lookup and get
   ref" operation (devpts_get_ref(inode)), along with a "put ref" op
   (devpts_put_ref()).

 - the pty master "tty->driver_data" field now contains the pts_fs_info,
   not the ptmx inode.

 - because we don't care about the ptmx inode any more as some kind of
   base index, the ref counting can now drop the inode games - it just
   gets the ref on the superblock.

 - the pts_fs_info now has a back-pointer to the super_block. That's so
   that we can easily look up the information we actually need. Although
   quite often, the pts fs info was actually all we wanted, and not having
   to look it up based on some magical inode makes things more
   straightforward.

In particular, now that "devpts_get_ref(inode)" operation should really
be the *only* place we need to look up what devpts instance we're
associated with, and we do it exactly once, at ptmx_open() time.

The other side of this is that one ptmx node could now be associated
with multiple different devpts instances - you could have a single
/dev/ptmx node, and then have multiple mount namespaces with their own
instances of devpts mounted on /dev/pts/.  And that's all perfectly sane
in a model where we just look up the pts instance at open time.

This will eventually allow us to get rid of our odd single-vs-multiple
pts instance model, but this patch in itself changes no semantics, only
an internal binding model.

Cc: Eric Biederman 
Cc: Peter Anvin 
Cc: Andy Lutomirski 
Cc: Al Viro 
Cc: Peter Hurley 
Cc: Serge Hallyn 
Cc: Willy Tarreau 
Cc: Aurelien Jarno 
Cc: Alan Cox 
Cc: Jann Horn 
Cc: Greg KH 
Cc: Jiri Slaby 
Cc: Florian Weimer 
Signed-off-by: Linus Torvalds 
Cc: Francesco Ruggeri 
Cc: "Herton R. Krzesinski" 
Signed-off-by: Greg Kroah-Hartman

tty/vt/keyboard: fix OOB access in do_compute_shiftstate()

2016-07-27T16:47:37+00:00

commit 510cccb5b0c8868a2b302a0ab524da7912da648b upstream.

The size of individual keymap in drivers/tty/vt/keyboard.c is NR_KEYS,
which is currently 256, whereas number of keys/buttons in input device (and
therefor in key_down) is much larger - KEY_CNT - 768, and that can cause
out-of-bound access when we do

	sym = U(key_maps[0][k]);

with large 'k'.

To fix it we should not attempt iterating beyond smaller of NR_KEYS and
KEY_CNT.

Also while at it let's switch to for_each_set_bit() instead of open-coding
it.

Reported-by: Sasha Levin 
Reviewed-by: Guenter Roeck 
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

tty: vt: Fix soft lockup in fbcon cursor blink timer.

2016-07-27T16:47:37+00:00

commit 1b45996d2ebf9680ccd0db875fc668aa025f40fd upstream.

We are getting somewhat random soft lockups with this signature:

[   86.992215] [] el1_irq+0xa0/0x10c
[   86.997082] [] cursor_timer_handler+0x30/0x54
[   87.002991] [] call_timer_fn+0x54/0x1a8
[   87.008378] [] run_timer_softirq+0x1c4/0x2bc
[   87.014200] [] __do_softirq+0x114/0x344
[   87.019590] [] irq_exit+0x74/0x98
[   87.024458] [] __handle_domain_irq+0x98/0xfc
[   87.030278] [] gic_handle_irq+0x94/0x190

This is caused by the vt visual_init() function calling into
fbcon_init() with a vc_cur_blink_ms value of zero.  This is a
transient condition, as it is later set to a non-zero value.  But, if
the timer happens to expire while the blink rate is zero, it goes into
an endless loop, and we get soft lockup.

The fix is to initialize vc_cur_blink_ms before calling the con_init()
function.

Signed-off-by: David Daney 
Acked-by: Pavel Machek 
Tested-by: Ming Lei 
Acked-by: Scot Doyle 
Tested-by: Henrique de Moraes Holschuh 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

QE-UART: add "fsl,t1040-ucc-uart" to of_device_id

2016-06-08T01:14:35+00:00

commit 11ca2b7ab432eb90906168c327733575e68d388f upstream.

New bindings use "fsl,t1040-ucc-uart" as the compatible for qe-uart.
So add it.

Signed-off-by: Zhao Qiang 
Signed-off-by: Greg Kroah-Hartman

serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios()

2016-06-01T19:15:53+00:00

commit b8995f527aac143e83d3900ff39357651ea4e0f6 upstream.

This patch fixes the broken serial log when changing the clock source
of uart device. Before disabling the original clock source, this patch
enables the new clock source to protect the clock off state for a split second.

Signed-off-by: Chanwoo Choi 
Reviewed-by: Marek Szyprowski 
Signed-off-by: Greg Kroah-Hartman 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Krzysztof Kozlowski

serial: 8250_mid: recognize interrupt source in handler

2016-06-01T19:15:53+00:00

commit c42850f1ae7e70056f852e67bb9dddf927853b47 upstream.

There is a special register that shows interrupt status by source. In
particular case the source can be a combination of DMA Tx, DMA Rx, and UART.

Read the register and call the handlers only for sources that request an
interrupt.

Fixes: 6ede6dcd87aa ("serial: 8250_mid: add support for DMA engine handling from UART MMIO")
Reviewed-by: Heikki Krogerus 
Signed-off-by: Andy Shevchenko 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_mid: use proper bar for DNV platform

2016-06-01T19:15:53+00:00

commit 107e15fc1f8d6ef69eac5f175971252f76e82f0d upstream.

Unlike Intel Medfield and Tangier platforms DNV uses PCI BAR0 for IO compatible
resources and BAR1 for MMIO. We need latter in a way to support DMA. Introduce
an additional field in the internal structure and pass PCI BAR based on device
ID.

Reported-by: "Lai, Poey Seng" 
Fixes: 6ede6dcd87aa ("serial: 8250_mid: add support for DMA engine handling from UART MMIO")
Reviewed-by: Heikki Krogerus 
Signed-off-by: Andy Shevchenko 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: fix divide error bug if baud rate is 0

2016-06-01T19:15:52+00:00

commit 6f210c18c1c0f016772c8cd51ae12a02bfb9e7ef upstream.

Since commit 21947ba654a6 ("serial: 8250_pci: replace switch-case by
formula"), the 8250 driver crashes in the byt_set_termios() function
with a divide error. This is caused by the fact that a baud rate of 0 (B0)
is not handled properly. Fix it by falling back to B9600 in this case.

Signed-off-by: David Müller 
Fixes: 21947ba654a6 ("serial: 8250_pci: replace switch-case by formula")
Suggested-by: Andy Shevchenko 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Greg Kroah-Hartman

Fix OpenSSH pty regression on close

2016-06-01T19:15:52+00:00

commit 0f40fbbcc34e093255a2b2d70b6b0fb48c3f39aa upstream.

OpenSSH expects the (non-blocking) read() of pty master to return
EAGAIN only if it has received all of the slave-side output after
it has received SIGCHLD. This used to work on pre-3.12 kernels.

This fix effectively forces non-blocking read() and poll() to
block for parallel i/o to complete for all ttys. It also unwinds
these changes:

1) f8747d4a466ab2cafe56112c51b3379f9fdb7a12
   tty: Fix pty master read() after slave closes

2) 52bce7f8d4fc633c9a9d0646eef58ba6ae9a3b73
   pty, n_tty: Simplify input processing on final close

3) 1a48632ffed61352a7810ce089dc5a8bcd505a60
   pty: Fix input race when closing

Inspired by analysis and patch from Marc Aurele La France 

Reported-by: Volth 
Reported-by: Marc Aurele La France 
BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=52
BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=2492
Signed-off-by: Brian Bloniarz 
Reviewed-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: fix hardware handshake selection

2016-06-01T19:15:52+00:00

commit 5be605ac9af979265d7b64c160ad9928088a78be upstream.

Commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when
hardware handshake is enabled") actually allowed to enable hardware
handshaking.
Before, the CRTSCTS flags was silently ignored.

As the DMA controller can't drive RTS (as explain in the commit message).
Ensure that hardware flow control stays disabled when DMA is used and FIFOs
are not available.

Signed-off-by: Alexandre Belloni 
Acked-by: Nicolas Ferre 
Fixes: 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled")
Signed-off-by: Greg Kroah-Hartman