Commit Graph

340 Commits

Author SHA1 Message Date
Andy Shevchenko d6d9d17aba tty: tty_io: Switch to vmalloc() fallback in case of TTY_NO_WRITE_SPLIT
When TTY_NO_WRITE_SPLIT is set and 64 KiB chunks are used, allow
vmalloc() fallback. Supply __GFP_RETRY_MAYFAIL to make kmalloc()
preferable over vmalloc() since we may want a better performance.

Note, both current users copy data to another buffer anyway, so
the type of our allocation doesn't affect their expectations.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211220133250.3070-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-21 09:18:44 +01:00
Jiri Slaby 31bc35d334 tty: add kernel-doc for tty_standard_install
It is the only missing exported function which is not documented. Fix
it.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-23-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26 16:27:43 +01:00
Jiri Slaby 3858128354 tty: add kernel-doc for more tty_driver functions
The only documented function for tty_driver structure
allocation/registration was __tty_alloc_driver(). Fix highlighting in
that comment.

And add kernel-doc headers to all tty_driver_kref_put(),
tty_register_driver(), and tty_unregister_driver() -- i.e. the main
ones. More to follow later.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-18-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26 16:27:43 +01:00
Jiri Slaby 796a75a987 tty: reformat kernel-doc in tty_io.c
Kernel-doc is a bit strict about some formatting. So fix these:
1) When there is a tab in comments, it thinks the line is a continuation
   one. So the description of the functions end up as descriptions of
   the last parameter described. Remove the tabs.

2) Remove newlines before parameters description and after the comments.
   This was not wrong per se, only inconsistent with the rest of the
   file.

3) Add periods to the end of sentences where appropriate.

4) Add "()" to function names and "%" to constants, so that they are
   properly highlighted.

By the above, this patch also unifies these docs with the other
kernel-doc's in this file.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-13-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26 16:27:43 +01:00
Jiri Slaby d78328bcc4 tty: remove file from tty_ldisc_ops::ioctl and compat_ioctl
After the previous patches, noone needs 'file' parameter in neither
ioctl hook from tty_ldisc_ops. So remove 'file' from both of them.

Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> [NFC]
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122094529.24171-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25 18:36:27 +01:00
Jiri Slaby 954a0881a9 tty: clean up whitespace in __do_SAK()
Remove spaces before the 'i' variable declaration and wrap parameters of
group_send_sig_info().

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118071911.12059-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25 18:31:32 +01:00
Jiri Slaby 8cb28417dd tty: remove tty NULL check from __do_SAK()
Both do_SAK_work() and vc_SAK() provide a valid tty to __do_SAK(), so
remove the check.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118071911.12059-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25 18:31:32 +01:00
Jiri Slaby 463d4c74bf tty: remove TTY_SOFT_SAK part from __do_SAK()
Remove the TTY_SOFT_SAK part. It is never defined, so this is only
confusing.

It was actually never defined since its introduction in
0.99.14g.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118071911.12059-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25 18:31:32 +01:00
Nguyen Dinh Phi bb2853a6a4 tty: Fix data race between tiocsti() and flush_to_ldisc()
The ops->receive_buf() may be accessed concurrently from these two
functions.  If the driver flushes data to the line discipline
receive_buf() method while tiocsti() is waiting for the
ops->receive_buf() to finish its work, the data race will happen.

For example:
tty_ioctl			|tty_ldisc_receive_buf
 ->tioctsi			| ->tty_port_default_receive_buf
				|  ->tty_ldisc_receive_buf
   ->hci_uart_tty_receive	|   ->hci_uart_tty_receive
    ->h4_recv                   |    ->h4_recv

In this case, the h4 receive buffer will be overwritten by the
latecomer, and we will lost the data.

Hence, change tioctsi() function to use the exclusive lock interface
from tty_buffer to avoid the data race.

Reported-by: syzbot+97388eb9d31b997fe1d0@syzkaller.appspotmail.com
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Link: https://lore.kernel.org/r/20210823000641.2082292-1-phind.uet@gmail.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-26 14:51:38 +02:00
Jiri Slaby 9f90a4ddef tty: drop put_tty_driver
put_tty_driver() is an alias for tty_driver_kref_put(). There is no need
for two exported identical functions, therefore switch all users of
old put_tty_driver() to new tty_driver_kref_put() and remove the former
for good.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Cc: Jens Taprogge <jens.taprogge@taprogge.org>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: Scott Branden <scott.branden@broadcom.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Lin <dtwlin@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Mathias Nyman <mathias.nyman@intel.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Acked-by: Alex Elder <elder@linaro.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723074317.32690-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-27 12:17:21 +02:00
Jiri Slaby cb9ea618ee tty: make tty_set_operations an inline
Since commit f34d7a5b70 (tty: The big operations rework) in 2008,
tty_set_operations() is a simple one-line assignment. There is no reason
for this to be an exported function, hence move it to a header and make
an inline from that.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723074317.32690-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-27 12:17:21 +02:00
Jiri Slaby d06e256f7a tty: fix kernel-doc for {start,stop}_tty
Commit f9e053dcfc (tty: Serialize tty flow control changes with
flow_lock) renamed start_tty to __start_tty and stop_tty to __stop_tty
and introduced new start_tty and stop_tty. But it left kernel-doc
comments on the old locations:
 tty_io.c:785: warning: expecting prototype for stop_tty(). Prototype was for __stop_tty() instead
 tty_io.c:816: warning: expecting prototype for start_tty(). Prototype was for __start_tty() instead

Fix that by moving the comments to appropriate locations.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210519072153.3859-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20 16:59:14 +02:00
Jiri Slaby 756a4e4a7a tty: fix kernel-doc for tty_{read,write}
After commits a9cbbb80e3 (tty: avoid using vfs_iocb_iter_write() for
redirected console writes) and dd78b0c483 (tty: implement read_iter),
the tty_read and tty_write kernel-doc comments don't match the code:
 tty_io.c:931: warning: Function parameter or member 'iocb' not described in 'tty_read'
 tty_io.c:931: warning: Function parameter or member 'to' not described in 'tty_read'
 tty_io.c:931: warning: Excess function parameter 'file' description in 'tty_read'
 tty_io.c:931: warning: Excess function parameter 'buf' description in 'tty_read'
 tty_io.c:931: warning: Excess function parameter 'count' description in 'tty_read'
 tty_io.c:931: warning: Excess function parameter 'ppos' description in 'tty_read'
 tty_io.c:1115: warning: Function parameter or member 'iocb' not described in 'file_tty_write'
 tty_io.c:1115: warning: Function parameter or member 'from' not described in 'file_tty_write'
 tty_io.c:1115: warning: expecting prototype for tty_write(). Prototype was for file_tty_write() instead

Fix them to correspond the reality, i.e. the switch from read/write to
read_iter/write_iter.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210519072153.3859-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20 16:59:14 +02:00
Xiaofei Tan fab491030c tty: tty_io: Remove return in void function
Remove return in void function, reported by checkpatch.pl.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-15-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan 27eab12932 tty: tty_io: Delete a blank line before EXPORT_SYMBOL(foo)
Delete a blank line before EXPORT_SYMBOL(foo) so that EXPORT_SYMBOL(foo)
immediately follow its function/variable, reported by checkpatch.pl.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-14-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan 5e4d5ac32b tty: tty_io: Fix an issue of code indent for conditional statements
Fix an issue of code indent for conditional statements,reported by
checkpatch.pl.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-13-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan 44969f8540 tty: tty_io: Remove the repeated word 'can'
Remove the repeated word 'can' following advice of checkpatch.pl

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-12-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan b426a5b815 tty: tty_io: Fix coding style issues of block comments
Fix coding style issues of block comments, reported by checkpatch.pl.
Besides, add a period at the end of the sentenses.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-11-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan d91c1a3eed tty: tty_io: Fix trailing whitespace issues
Fix trailing whitespace issues, reported by checkpatch.pl.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-10-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan 94bc2eb5fb tty: tty_io: Fix spaces required around that ':'
Fix spaces required around that ':', reported by checkpatch.pl.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-9-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan e73b240785 tty: tty_io: Add a blank line after declarations
Add a blank line after declarations, reported by checkpatch.pl.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-8-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:13 +02:00
Xiaofei Tan 395e783371 tty: tty_io: Remove spaces before tabs
Remove spaces before tabs following the advice of checkpatch.pl.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-7-git-send-email-tanxiaofei@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 18:29:12 +02:00
Jiri Slaby 64d608db38 tty: cumulate and document tty_struct::ctrl* members
Group the ctrl members under a single struct called ctrl. The new struct
contains 'pgrp', 'session', 'pktstatus', and 'packet'. 'pktstatus' and
'packet' used to be bits in a bitfield. The struct also contains the
lock protecting them to share the same cache line.

Note that commit c545b66c69 (tty: Serialize tcflow() with other tty
flow control changes) added a padding to the original bitfield. It was
for the bitfield to occupy a whole 64b word to avoid interferring stores
on Alpha (cannot we evaporate this arch with weird implications to C
code yet?). But it doesn't work as expected as the padding
(tty_struct::ctrl_unused) is aligned to a 8B boundary too and occupies
some bytes from the next word.

So make it reliable by:
1) setting __aligned of the struct -- that aligns the start, and
2) making 'unsigned long unused[0]' as the last member of the struct --
   pads the end.

Add a kerneldoc comment for this grouped members.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20210505091928.22010-14-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 16:57:16 +02:00
Jiri Slaby 6e94dbc7a4 tty: cumulate and document tty_struct::flow* members
Group the flow flags under a single struct called flow. The new struct
contains 'stopped' and 'tco_stopped' bools which used to be bits in a
bitfield. The struct also contains the lock protecting them to
potentially share the same cache line.

Note that commit c545b66c69 (tty: Serialize tcflow() with other tty
flow control changes) added a padding to the original bitfield. It was
for the bitfield to occupy a whole 64b word to avoid interferring stores
on Alpha (cannot we evaporate this arch with weird implications to C
code yet?). But it doesn't work as expected as the padding
(tty_struct::unused) is aligned to a 8B boundary too and occupies some
bytes from the next word.

So make it reliable by:
1) setting __aligned of the struct -- that aligns the start, and
2) making 'unsigned long unused[0]' as the last member of the struct --
   pads the end.

This is also the perfect time to start the documentation of tty_struct
where all this lives. So we start by documenting what these bools
actually serve for. And why we do all the alignment dances. Only the few
up-to-date information from the Theodore's comment made it into this new
Kerneldoc comment.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: "Maciej W. Rozycki" <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/20210505091928.22010-13-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 16:57:16 +02:00
Greg Kroah-Hartman dd9f611442 tty: make tty_release_redirect() static
No one calls this outside of the tty_io.c file, so mark this static and
do not export the symbol anymore.

Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20210408125134.3016837-11-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15 10:28:30 +02:00
Greg Kroah-Hartman 98602c010c tty: create internal tty.h file
There are a number of functions and #defines in include/linux/tty.h that
do not belong there as they are private to the tty core code.

Create an initial drivers/tty/tty.h file and copy the odd "tty logging"
macros into it to seed the file with some initial things that we know
nothing outside of the tty core should be calling.

Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20210408125134.3016837-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15 10:22:17 +02:00
Johan Hovold 885c77d528 tty: refactor TIOCSSERIAL handling
Factor out the deprecated serial flags handling and tty-operation check
shared with the compat TIOCSSERIAL handler.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-6-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10 10:36:34 +02:00
Johan Hovold 1b7bc6b10a tty: use pr_warn_ratelimited() for deprecated serial flags
Use pr_warn_ratelimited() when warning about deprecated serial flags
instead of open coding.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-5-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10 10:36:34 +02:00
Johan Hovold 1b8b20868a tty: fix return value for unsupported ioctls
Drivers should return -ENOTTY ("Inappropriate I/O control operation")
when an ioctl isn't supported, while -EINVAL is used for invalid
arguments.

Fix up the TIOCMGET, TIOCMSET and TIOCGICOUNT helpers which returned
-EINVAL when a tty driver did not implement the corresponding
operations.

Note that the TIOCMGET and TIOCMSET helpers predate git and do not get a
corresponding Fixes tag below.

Fixes: d281da7ff6 ("tty: Make tiocgicount a handler")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10 10:36:34 +02:00
Greg Kroah-Hartman 280def1e1c Merge 5.12-rc3 into tty-next
Resolves a merge issue with:
	drivers/tty/hvc/hvcs.c
and we want the tty/serial fixes from 5.12-rc3 in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-15 08:43:49 +01:00
Jiri Slaby a846dcf9d7 tty: localise ptychar and make it const
ptychar was not const, so mark it as such. And move this variable to the
only place where it's used.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-36-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:09 +01:00
Jiri Slaby a872ab4d6d tty: let tty_unregister_driver return void
Now that noone checks the return value, switch the return type of
tty_unregister_driver to void. We can do that as we always return zero.

Generally, drivers are not allowed to call tty_unregister_driver while
there are open devices.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-35-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:09 +01:00
Greg Kroah-Hartman c776b77a27 Revert "drivers:tty:pty: Fix a race causing data loss on close"
This reverts commit 33d4ae9885.

Pierre-Louis writes:

	Our SOF/audio CI shows an across-the-board regression when we try v5.12-rc1,
	specifically on pause/resume tests with an interactive terminal running 'aplay
	-i' commands managed by expect to simulate the user pressing the space bar to
	pause/unpause. It turns out the processes are not longer killed and the audio
	devices remain busy (see publicly available test results listed below).

	git bisect points to commit 33d4ae9885 ("drivers:tty:pty: Fix a race
	causing data loss on close"). Reverting the patch fixes the issue on all test
	devices.

	Further analysis with Corey Minyard points to a problem where a slave tty will
	not get a SIGHUP when the master is closed.

So revert this for now:

Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/00154592-c5ee-aaba-956e-b265473b53bc@linux.intel.com
Cc: Corey Minyard <cminyard@mvista.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mark Brown <broonie@kernel.org>,
Fixes: 33d4ae9885 ("drivers:tty:pty: Fix a race causing data loss on close")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:27:56 +01:00
Linus Torvalds e4286926ab TTY/Serial driver changes for 5.12-rc1
Here is the big set of tty/serial driver changes for 5.12-rc1.
 
 Nothing huge, just lots of good cleanups and additions:
 	- Your n_tty line discipline cleanups
 	- vt core cleanups and reworks to make the code more "modern"
 	- stm32 driver additions
 	- tty led support added to the tty core and led layer
 	- minor serial driver fixups and additions
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the big set of tty/serial driver changes for 5.12-rc1.

  Nothing huge, just lots of good cleanups and additions:

   - n_tty line discipline cleanups

   - vt core cleanups and reworks to make the code more "modern"

   - stm32 driver additions

   - tty led support added to the tty core and led layer

   - minor serial driver fixups and additions

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (54 commits)
  serial: core: Remove BUG_ON(in_interrupt()) check
  vt_ioctl: Remove in_interrupt() check
  dt-bindings: serial: imx: Switch to my personal address
  vt: keyboard, use new API for keyboard_tasklet
  serial: stm32: improve platform_get_irq condition handling in init_port
  serial: ifx6x60: Remove driver for deprecated platform
  tty: fix up iterate_tty_read() EOVERFLOW handling
  tty: fix up hung_up_tty_read() conversion
  tty: fix up hung_up_tty_write() conversion
  tty: teach the n_tty ICANON case about the new "cookie continuations" too
  tty: teach n_tty line discipline about the new "cookie continuations"
  tty: clean up legacy leftovers from n_tty line discipline
  tty: implement read_iter
  tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer
  serial: remove sirf prima/atlas driver
  serial: mxs-auart: Remove <asm/cacheflush.h>
  serial: mxs-auart: Remove serial_mxs_probe_dt()
  serial: fsl_lpuart: Use of_device_get_match_data()
  dt-bindings: serial: renesas,hscif: Add r8a779a0 support
  tty: serial: Drop unused efm32 serial driver
  ...
2021-02-20 21:28:04 -08:00
Linus Torvalds 3342ff2698 tty: protect tty_write from odd low-level tty disciplines
Al root-caused a new warning from syzbot to the ttyprintk tty driver
returning a write count larger than the data the tty layer actually gave
it.  Which confused the tty write code mightily, and with the new
iov_iter based code, caused a WARNING in iov_iter_revert().

syzbot correctly bisected the source of the new warning to commit
9bb48c82ac ("tty: implement write_iter"), but the oddity goes back
much further, it just didn't get caught by anything before.

Reported-by: syzbot+3d2c27c2b7dc2a94814d@syzkaller.appspotmail.com
Fixes: 9bb48c82ac ("tty: implement write_iter")
Debugged-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-20 21:15:00 -08:00
Linus Torvalds a9cbbb80e3 tty: avoid using vfs_iocb_iter_write() for redirected console writes
It turns out that the vfs_iocb_iter_{read,write}() functions are
entirely broken, and don't actually use the passed-in file pointer for
IO - only for the preparatory work (permission checking and for the
write_iter function lookup).

That worked fine for overlayfs, which always builds the new iocb with
the same file pointer that it passes in, but in the general case it ends
up doing nonsensical things (and could cause an iterator call that
doesn't even match the passed-in file pointer).

This subtly broke the tty conversion to write_iter in commit
9bb48c82ac ("tty: implement write_iter"), because the console
redirection didn't actually end up redirecting anything, since the
passed-in file pointer was basically ignored, and the actual write was
done with the original non-redirected console tty after all.

The main visible effect of this is that the console messages were no
longer logged to /var/log/boot.log during graphical boot.

Fix the issue by simply not using the vfs write "helper" function at
all, and just redirecting the write entirely internally to the tty
layer.  Do the target writability permission checks when actually
registering the target tty with TIOCCONS instead of at write time.

Fixes: 9bb48c82ac ("tty: implement write_iter")
Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-29 13:12:17 -08:00
Sami Tolvanen 9f12e37cae Commit 9bb48c82ac ("tty: implement write_iter") converted the tty
layer to use write_iter. Fix the redirected_tty_write declaration
also in n_tty and change the comparisons to use write_iter instead of
write.

[ Also moved the declaration of redirected_tty_write() to the proper
  location in a header file. The reason for the bug was the bogus extern
  declaration in n_tty.c silently not matching the changed definition in
  tty_io.c, and because it wasn't in a shared header file, there was no
  cross-checking of the declaration.

  Sami noticed because Clang's Control Flow Integrity checking ended up
  incidentally noticing the inconsistent declaration.    - Linus ]

Fixes: 9bb48c82ac ("tty: implement write_iter")
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-25 12:08:07 -08:00
Linus Torvalds 17749851eb tty: fix up hung_up_tty_write() conversion
In commit "tty: implement write_iter", I left the write_iter conversion
of the hung up tty case alone, because I incorrectly thought it didn't
matter.

Jiri showed me the errors of my ways, and pointed out the problems with
that incomplete conversion.  Fix it all up.

Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22 11:01:55 +01:00
Linus Torvalds e71a8d5cf4 tty: fix up iterate_tty_read() EOVERFLOW handling
When I converted the tty_ldisc_ops 'read()' function to take a kernel
pointer, I was a bit too aggressive about the ldisc returning EOVERFLOW.

Yes, we want to have EOVERFLOW override any partially read data (because
the whole point is that the buffer was too small for the whole packet,
and we don't want to see partial packets), but it shouldn't override a
previous EFAULT.

And in fact, it really is just EOVERFLOW that is special and should
throw away any partially read data, not "any error".  Admittedly
EOVERFLOW is currently the only one that can happen for a continuation
read - and if the first read iteration returns an error we won't have this issue.

So this is more of a technicality, but let's just make the intent very
explicit, and re-organize the error handling a bit so that this is all
clearer.

Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22 10:53:10 +01:00
Linus Torvalds ddc5fda745 tty: fix up hung_up_tty_read() conversion
In commit "tty: implement read_iter", I left the read_iter conversion of
the hung up tty case alone, because I incorrectly thought it didn't
matter.

Jiri showed me the errors of my ways, and pointed out the problems with
that incomplete conversion.  Fix it all up.

Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22 10:53:07 +01:00
Linus Torvalds c7135bbe5a tty: fix up hung_up_tty_write() conversion
In commit "tty: implement write_iter", I left the write_iter conversion
of the hung up tty case alone, because I incorrectly thought it didn't
matter.

Jiri showed me the errors of my ways, and pointed out the problems with
that incomplete conversion.  Fix it all up.

Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22 10:52:43 +01:00
Greg Kroah-Hartman 3cfade53c7 Merge branch 'tty-splice' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into tty-next
Fixes both the "splice/sendfile to a tty" and "splice/sendfile from a
tty" regression from 5.10.

* 'tty-splice' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux:
  tty: teach the n_tty ICANON case about the new "cookie continuations" too
  tty: teach n_tty line discipline about the new "cookie continuations"
  tty: clean up legacy leftovers from n_tty line discipline
  tty: implement read_iter
  tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer
  tty: implement write_iter
2021-01-21 09:40:55 +01:00
Greg Kroah-Hartman 494e63ee9c Merge 9bb48c82ac ("tty: implement write_iter") into tty-linus
We want the single "splice/sendfile to a tty" regression fix into
tty-linus so it can get into 5.11-final, while the larger patch series
fixing "splice/sendfile from a tty" should wait for 5.12-rc1 so that we
get more testing.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-21 09:38:37 +01:00
Linus Torvalds 9bb48c82ac tty: implement write_iter
This makes the tty layer use the .write_iter() function instead of the
traditional .write() functionality.

That allows writev(), but more importantly also makes it possible to
enable .splice_write() for ttys, reinstating the "splice to tty"
functionality that was lost in commit 36e2c7421f ("fs: don't allow
splice read/write without explicit ops").

Fixes: 36e2c7421f ("fs: don't allow splice read/write without explicit ops")
Reported-by: Oliver Giles <ohw.giles@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20 16:48:47 -08:00
Linus Torvalds dd78b0c483 tty: implement read_iter
Now that the ldisc read() function takes kernel pointers, it's fairly
straightforward to make the tty file operations use .read_iter() instead
of .read().

That automatically gives us vread() and friends, and also makes it
possible to do .splice_read() on ttys again.

Fixes: 36e2c7421f ("fs: don't allow splice read/write without explicit ops")
Reported-by: Oliver Giles <ohw.giles@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20 16:48:47 -08:00
Linus Torvalds 3b830a9c34 tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer
The tty line discipline .read() function was passed the final user
pointer destination as an argument, which doesn't match the 'write()'
function, and makes it very inconvenient to do a splice method for
ttys.

This is a conversion to use a kernel buffer instead.

NOTE! It does this by passing the tty line discipline ->read() function
an additional "cookie" to fill in, and an offset into the cookie data.

The line discipline can fill in the cookie data with its own private
information, and then the reader will repeat the read until either the
cookie is cleared or it runs out of data.

The only real user of this is N_HDLC, which can use this to handle big
packets, even if the kernel buffer is smaller than the whole packet.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20 16:48:47 -08:00
Corey Minyard 33d4ae9885 drivers:tty:pty: Fix a race causing data loss on close
Remove the tty_vhangup() from the pty code and just release the
redirect.  The tty_vhangup() results in data loss and data out of order
issues.

If you write to a pty master an immediately close the pty master, the
receiver might get a chunk of data dropped, but then receive some later
data.  That's obviously something rather unexpected for a user.  It
certainly confused my test program.

It turns out that tty_vhangup() on the slave pty gets called from
pty_close(), and that causes the data on the slave side to be flushed,
but due to races more data can be copied into the slave side's buffer
after that.  Consider the following sequence:

thread1          thread2         thread3
-------          -------         -------
 |                |-write data into buffer,
 |                | n_tty buffer is filled
 |                | along with other buffers
 |                |-pty_close(master)
 |                |--tty_vhangup(slave)
 |                |---tty_ldisc_hangup()
 |                |----n_tty_flush_buffer()
 |                |-----reset_buffer_flags()
 |-n_tty_read()   |
 |--up_read(&tty->termios_rwsem);
 |                |------down_read(&tty->termios_rwsem)
 |                |------clear n_tty buffer contents
 |                |------up_read(&tty->termios_rwsem)
 |--tty_buffer_flush_work()       |
 |--schedules work calling        |
 |  flush_to_ldisc()              |
 |                                |-flush_to_ldisc()
 |                                |--receive_buf()
 |                                |---tty_port_default_receive_buf()
 |                                |----tty_ldisc_receive_buf()
 |                                |-----n_tty_receive_buf2()
 |                                |------n_tty_receive_buf_common()
 |                                |-------down_read(&tty->termios_rwsem)
 |                                |-------__receive_buf()
 |                                |       copies data into n_tty buffer
 |                                |-------up_read(&tty->termios_rwsem)
 |--down_read(&tty->termios_rwsem)
 |--copy buffer data to user

>From this sequence, you can see that thread2 writes to the buffer then
only clears the part of the buffer in n_tty.  The n_tty receive buffer
code then copies more data into the n_tty buffer.

But part of the vhangup, releasing the redirect, is still required to
avoid issues with consoles running on pty slaves.  So do that.
As far as I can tell, that is all that should be required.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Link: https://lore.kernel.org/r/20201124004902.1398477-3-minyard@acm.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:30:55 +01:00
Corey Minyard f446776ebf tty: Export redirect release
This will be required by the pty code when it removes tty_vhangup() on
master close.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Link: https://lore.kernel.org/r/20201124004902.1398477-2-minyard@acm.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 16:30:55 +01:00
Uwe Kleine-König d20c219c73 tty: new helper function tty_get_icount()
For a given struct tty_struct this yields the corresponding statistics
about sent and received characters (and some more) which is needed to
implement an LED trigger for tty devices.

The new function is then used to simplify tty_tiocgicount().

Reviewed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201218104246.591315-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-28 16:09:29 +01:00
Uwe Kleine-König 4ea3cd65e0 tty: rename tty_kopen() and add new function tty_kopen_shared()
Introduce a new function tty_kopen_shared() that yields a struct
tty_struct. The semantic difference to tty_kopen() is that the tty is
expected to be used already. So rename tty_kopen() to
tty_kopen_exclusive() for clearness, adapt the single user and put the
common code in a new static helper function.

tty_kopen_shared is to be used to implement an LED trigger for tty
devices in one of the next patches.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201218104246.591315-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-28 16:09:11 +01:00