Commit Graph

217 Commits

Author SHA1 Message Date
Meng Xu 8ffb82094b tty: vt: remove multi-fetch, derive font.height from font.data
In con_font_set(), when we need to guess font height (for
compat reasons?), the current approach uses multiple userspace
fetches, i.e., get_user(tmp, &charmap[32*i+h-1]), to derive
the height. This has two drawbacks:

1. performance: accessing userspace memory is less efficient than
directly de-reference the byte

2. security: a more critical problem is that the height derived
might not match with the actual font.data. This is because a user
thread might race condition to change the memory of op->data after
the op->height guessing but before the second fetch: font.data =
memdup_user(op->data, size). Leaving font.height = 32 while the
actual height is 1 or vice-versa.

This patch tries to resolve both issues by re-locating the height
guessing part after the font.data is fetched in. In this way, the
userspace data is fetched in one shot and we directly dereference
the font.data in kernel space to probe for the height.

Signed-off-by: Meng Xu <mengxu.gatech@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-20 14:06:45 +02:00
Joe Perches bccf1da354 vt: Use consistent logging style
vt has a mixture of pr_<level> and printk.
Convert to using only pr_<level>.

Miscellanea:

o Coalesce formats
o Realign arguments
o Add missing braces around an if/else with the printk conversion

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-04 10:52:01 +02:00
Thomas Meyer f0a8d84fa1 vt: Use bsearch library function in is_double_width
Use bsearch library function instead of duplicated functionality.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-18 18:31:48 +02:00
Adam Borowski 1c65a879cc vt: fix \e[2m using the wrong placeholder color on graphical consoles
Only vgacon and sisusbcon did it right, the rest (via generic code) tried
underline (usually cyan).

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:20:08 +02:00
Greg Kroah-Hartman e0ac3f9825 Merge branch 'vt_copy_cleanup' into tty-next
The vt copy_from/to_user cleanups were in a separate branch for others
to work off of.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:19:02 +02:00
Adam Borowski f8564c93e0 vt: drop access_ok() calls in unimap ioctls
Done by copy_{from,to}_user().

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:07:36 +02:00
Adam Borowski 4f1be1b5d9 vt: use memdup_user in PIO_UNIMAP ioctl
Again, a nice linear transfer that simplifies the code.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:07:36 +02:00
Adam Borowski 915f0a8d28 vt: use copy_to_user instead of __put_user in GIO_UNIMAP ioctl
A nice big linear transfer, no need to flip stac/PAN/etc every half-entry.
Also, yay __put_user() after checking only read.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:07:36 +02:00
Adam Borowski 6987dc8a70 vt: fix unchecked __put_user() in tioclinux ioctls
Only read access is checked before this call.

Actually, at the moment this is not an issue, as every in-tree arch does
the same manual checks for VERIFY_READ vs VERIFY_WRITE, relying on the MMU
to tell them apart, but this wasn't the case in the past and may happen
again on some odd arch in the future.

If anyone cares about 3.7 and earlier, this is a security hole (untested)
on real 80386 CPUs.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
CC: stable@vger.kernel.org # v3.7-
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:07:36 +02:00
Adam Borowski cc1e66f92b vt: use copy_from/to_user instead of __get/put_user for scrnmap ioctls
Linus wants to get rid of these functions, and these uses are especially
egregious: they copy a big linear array element by element.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:07:36 +02:00
Andy Shevchenko 7b6d539944 tty/vt/keyboard: Remove AVR32 bits from the driver
AVR32 is gone. Now it's time to clean up the driver by removing
leftovers that was used by AVR32 related code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-18 16:34:55 +02:00
Adam Borowski 7f1534e172 vt: make mouse selection of non-ASCII consistent
For some reason a handful of ISO-8859-1 symbols are excluded from "word
chars" while the vast majority of Unicode is hard-coded as included, even
when inappropriate (we really would want to _not_ select line-drawing/etc).
Those symbols are: ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿×÷

Thus, let's not special-case any non-ASCII anymore.  Attempts to set these
via ioctl will be silently ignored.

As an extra bonus, we debloat the kernel by 128 bytes.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-11 21:39:15 +02:00
Adam Borowski 7d6d44aee0 vt: set mouse selection word-chars to gpm's default
Since forever, gpm was this code's only user, and it overrides the table on
start so the default was never seen -- until Bill Allombert's "consolation"
came in.  The in-kernel set is "A-Za-z0-9_" which fails to catch typical
file names, etc.  Let's change this to gpm's conservative default, ie
"-A-Za-z0-9_./"; most terminals include more, for example xfce4-terminal has
"-A-Za-z0-9,./?%&#:_=+@~".

There's some discussion at https://bugs.debian.org/846587

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-11 21:39:14 +02:00
Greg Kroah-Hartman 9ccd8d7445 Merge 4.11-rc5 into tty-next
We want the serial fixes in here as well to handle merge issues.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-03 14:18:16 +02:00
Tim Gardner a4199f5eb8 tty: Disable default console blanking interval
BugLink: http://bugs.launchpad.net/bugs/869017

Console blanking is not enabling DPMS power saving (thereby negating any
power-saving benefit), and is simply turning the screen content blank. This
means that any crash output is invisible which is unhelpful on a server
(virtual or otherwise).

Furthermore, CRT burn in concerns should no longer govern the default case.
Affected users could always set consoleblank on the kernel command line.

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-31 16:56:10 +02:00
Ingo Molnar 658b299580 sched/headers: Remove duplicate #include <linux/sched/debug.h> line
Vito Caputo reported that the sched.h split-up series
introduced a duplicate #include <linux/sched/debug.h> line
in drivers/tty/vt/keyboard.c.

Remove it.

Reported-by: Vito Caputo <vcaputo@pengaru.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-28 09:56:03 +02:00
Ingo Molnar b17b01533b sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:34 +01:00
Ingo Molnar 3f07c01441 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Michal Hocko 9af744d743 lib/show_mem.c: teach show_mem to work with the given nodemask
show_mem() allows to filter out node specific data which is irrelevant
to the allocation request via SHOW_MEM_FILTER_NODES.  The filtering is
done in skip_free_areas_node which skips all nodes which are not in the
mems_allowed of the current process.  This works most of the time as
expected because the nodemask shouldn't be outside of the allocating
task but there are some exceptions.  E.g.  memory hotplug might want to
request allocations from outside of the allowed nodes (see
new_node_page).

Get rid of this hardcoded behavior and push the allocation mask down the
show_mem path and use it instead of cpuset_current_mems_allowed.  NULL
nodemask is interpreted as cpuset_current_mems_allowed.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170117091543.25850-5-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22 16:41:30 -08:00
Manuel Schölling bcd375f7f7 console: Add callback to flush scrollback buffer to consw struct
This new callback is in preparation for persistent scrollback buffer
support for VGA consoles.
With a single scrollback buffer for all consoles, we could flush the
buffer just by invocating consw->con_switch(). But when each VGA console
has its own scrollback buffer, we need a new callback to tell the
video console driver which buffer to flush.

Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de>
Reviewed-by: Andrey Utkin <andrey_utkin@fastmail.com>
Tested-by: Andrey Utkin <andrey_utkin@fastmail.com>
Tested-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-25 11:54:02 +01:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Linus Torvalds c11a6cfb01 Merge branch 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo:
 "Mostly patches to initialize workqueue subsystem earlier and get rid
  of keventd_up().

  The patches were headed for the last merge cycle but got delayed due
  to a bug found late minute, which is fixed now.

  Also, to help debugging, destroy_workqueue() is more chatty now on a
  sanity check failure."

* 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: move wq_numa_init() to workqueue_init()
  workqueue: remove keventd_up()
  debugobj, workqueue: remove keventd_up() usage
  slab, workqueue: remove keventd_up() usage
  power, workqueue: remove keventd_up() usage
  tty, workqueue: remove keventd_up() usage
  mce, workqueue: remove keventd_up() usage
  workqueue: make workqueue available early during boot
  workqueue: dump workqueue state on sanity check failures in destroy_workqueue()
2016-12-13 12:59:57 -08:00
Waiman Long 7edd7e82b9 console: Move userspace I/O out of console_lock to fix lockdep warning
When running certain workload on a debug kernel with lockdep turned on,
a ppc64 kvm guest could sometimes hit the following lockdep warning:

  [ INFO: possible circular locking dependency detected ]
  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&mm->mmap_sem);
                                lock(console_lock);
                                lock(&mm->mmap_sem);
   lock(cpu_hotplug.lock);

  *** DEADLOCK ***

Looking at the console code, the console_lock-->mmap_sem scenario will
only happen when reading or writing the console unicode map leading to
a page fault.

To break this circular locking dependency, all the userspace I/O
operations in consolemap.c are now moved outside of the console_lock
critical sections so that the mmap_sem won't be acquired when holding
the console_lock.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-29 21:42:40 +01:00
Maciej S. Szmigiero 31b5929d53 vt: fix Scroll Lock LED trigger name
There is a disagreement between drivers/tty/vt/keyboard.c and
drivers/input/input-leds.c with regard to what is a Scroll Lock LED
trigger name: input calls it "kbd-scrolllock", but vt calls it
"kbd-scrollock" (two l's).
This prevents Scroll Lock LED trigger from binding to this LED by default.

Since it is a scroLL Lock LED, this interface was introduced only about a
year ago and in an Internet search people seem to reference this trigger
only to set it to this LED let's simply rename it to "kbd-scrolllock".

Also, it looks like this was supposed to be changed before this code was
merged: https://lkml.org/lkml/2015/6/9/697 but it was done only on
the input side.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: stable <stable@vger.kernel.org> # 4.2+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-16 10:03:52 +01:00
Askar Safin 26ba68d2f8 tty: typo in comments in drivers/tty/vt/keyboard.c
Fixed typo in comments in drivers/tty/vt/keyboard.c

Signed-off-by: Askar Safin <safinaskar@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-10 15:10:37 +01:00
Greg Kroah-Hartman 5131dcd781 Merge 4.9-rc3 into tty-next
We want the serial/tty fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 06:42:10 -04:00
Scot Doyle 009e39ae44 vt: clear selection before resizing
When resizing a vt its selection may exceed the new size, resulting in
an invalid memory access [1]. Clear the selection before resizing.

[1] http://lkml.kernel.org/r/CACT4Y+acDTwy4umEvf5ROBGiRJNrxHN4Cn5szCXE5Jw-d1B=Xw@mail.gmail.com

Reported-and-tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 17:19:35 +02:00
Dmitry Vyukov 32b2921e6a tty: limit terminal size to 4M chars
Size of kmalloc() in vc_do_resize() is controlled by user.
Too large kmalloc() size triggers WARNING message on console.
Put a reasonable upper bound on terminal size to prevent WARNINGs.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
CC: David Rientjes <rientjes@google.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-kernel@vger.kernel.org
Cc: syzkaller@googlegroups.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 16:41:56 +02:00
Jiri Slaby 7c918cdceb tty: vt, rename variables to sane names
This makes the code understandable at least. No functional changes.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 16:37:44 +02:00
Jiri Slaby 210fd7460e tty: vt, compute vc offsets in advance
Only improves readability, no functional changes.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 16:37:44 +02:00
Jiri Slaby 35cc56f9a3 tty: vgacon+sisusb, move scrolldelta to a common helper
The code is mirrorred in scrolldelta implementations of both vgacon
and sisusb. Let's move the code to a separate helper where we will
perform a common cleanup and further changes.

While we are moving the code, make it linear and save one indentation
level. This is done by returning from the "!lines" then-branch
immediatelly. This allows flushing the else-branch 1 level to the
left, obviously.

Few more new lines and comments were added too.

And do not forget to export the helper function given sisusb can be
built as module.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 16:37:44 +02:00
Jiri Slaby 89765b9424 tty: vt, unify scrolling functions
Both scrup and scrdown are copies of the same code except source and
destination pointers computation. Unify those functions into a single
one named con_scroll.

Note that scrdown used step to compute the destination, while scrup
did the computation explicitly. We sticked to the latter here.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 16:37:43 +02:00
Jiri Slaby d705ff3818 tty: vt, cleanup and document con_scroll
Scrolling helpers scrup and scrdown both accept 'top' and 'bottom' as
unsigned int. Number of lines 'nr' is accepted as int, but all callers
pass down unsigned too. So change the type of 'nr' to unsigned too.
Now, promote unsigned int from the helpers up to the con_scroll
hook which actually accepted all those as signed int.

Next, the 'dir' parameter can have only two values and we define
constants for that: SM_UP and SM_DOWN. Switch them to enum and do
proper type checking on 'dir' too.

Finally, document the behaviour of the hook.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-usb@vger.kernel.org>
Cc: <linux-parisc@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 16:37:43 +02:00
Jiri Slaby 42acfc6615 tty: vt, fix bogus division in csi_J
In csi_J(3), the third parameter of scr_memsetw (vc_screenbuf_size) is
divided by 2 inappropriatelly. But scr_memsetw expects size, not
count, because it divides the size by 2 on its own before doing actual
memset-by-words.

So remove the bogus division.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Petr Písař <ppisar@redhat.com>
Fixes: f8df13e0a9 (tty: Clean console safely)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-27 16:00:31 +02:00
Tejun Heo 8bc4a04455 Merge branch 'for-4.9' into for-4.10 2016-10-19 12:12:40 -04:00
Linus Torvalds 563873318d Merge branch 'printk-cleanups'
Merge my system logging cleanups, triggered by the broken '\n' patches.

The line continuation handling has been broken basically forever, and
the code to handle the system log records was both confusing and
dubious.  And it would do entirely the wrong thing unless you always had
a terminating newline, partly because it couldn't actually see whether a
message was marked KERN_CONT or not (but partly because the LOG_CONT
handling in the recording code was rather confusing too).

This re-introduces a real semantically meaningful KERN_CONT, and fixes
the few places I noticed where it was missing.  There are probably more
missing cases, since KERN_CONT hasn't actually had any semantic meaning
for at least four years (other than the checkpatch meaning of "no log
level necessary, this is a continuation line").

This also allows the combination of KERN_CONT and a log level.  In that
case the log level will be ignored if the merging with a previous line
is successful, but if a new record is needed, that new record will now
get the right log level.

That also means that you can at least in theory combine KERN_CONT with
the "pr_info()" style helpers, although any use of pr_fmt() prefixing
would make that just result in a mess, of course (the prefix would end
up in the middle of a continuing line).

* printk-cleanups:
  printk: make reading the kernel log flush pending lines
  printk: re-organize log_output() to be more legible
  printk: split out core logging code into helper function
  printk: reinstate KERN_CONT for printing continuation lines
2016-10-10 09:29:50 -07:00
Linus Torvalds 4bcc595ccd printk: reinstate KERN_CONT for printing continuation lines
Long long ago the kernel log buffer was a buffered stream of bytes, very
much like stdio in user space.  It supported log levels by scanning the
stream and noticing the log level markers at the beginning of each line,
but if you wanted to print a partial line in multiple chunks, you just
did multiple printk() calls, and it just automatically worked.

Except when it didn't, and you had very confusing output when different
lines got all mixed up with each other.  Then you got fragment lines
mixing with each other, or with non-fragment lines, because it was
traditionally impossible to tell whether a printk() call was a
continuation or not.

To at least help clarify the issue of continuation lines, we added a
KERN_CONT marker back in 2007 to mark continuation lines:

  4749252776 ("printk: add KERN_CONT annotation").

That continuation marker was initially an empty string, and didn't
actuall make any semantic difference.  But it at least made it possible
to annotate the source code, and have check-patch notice that a printk()
didn't need or want a log level marker, because it was a continuation of
a previous line.

To avoid the ambiguity between a continuation line that had that
KERN_CONT marker, and a printk with no level information at all, we then
in 2009 made KERN_CONT be a real log level marker which meant that we
could now reliably tell the difference between the two cases.

  5fd29d6ccb ("printk: clean up handling of log-levels and newlines")

and we could take advantage of that to make sure we didn't mix up
continuation lines with lines that just didn't have any loglevel at all.

Then, in 2012, the kernel log buffer was changed to be a "record" based
log, where each line was a record that has a loglevel and a timestamp.

You can see the beginning of that conversion in commits

  e11fea92e1 ("kmsg: export printk records to the /dev/kmsg interface")
  7ff9554bb5 ("printk: convert byte-buffer to variable-length record buffer")

with a number of follow-up commits to fix some painful fallout from that
conversion.  Over all, it took a couple of months to sort out most of
it.  But the upside was that you could have concurrent readers (and
writers) of the kernel log and not have lines with mixed output in them.

And one particular pain-point for the record-based kernel logging was
exactly the fragmentary lines that are generated in smaller chunks.  In
order to still log them as one recrod, the continuation lines need to be
attached to the previous record properly.

However the explicit continuation record marker that is actually useful
for this exact case was actually removed in aroundm the same time by commit

  61e99ab8e3 ("printk: remove the now unnecessary "C" annotation for KERN_CONT")

due to the incorrect belief that KERN_CONT wasn't meaningful.  The
ambiguity between "is this a continuation line" or "is this a plain
printk with no log level information" was reintroduced, and in fact
became an even bigger pain point because there was now the whole
record-level merging of kernel messages going on.

This patch reinstates the KERN_CONT as a real non-empty string marker,
so that the ambiguity is fixed once again.

But it's not a plain revert of that original removal: in the four years
since we made KERN_CONT an empty string again, not only has the format
of the log level markers changed, we've also had some usage changes in
this area.

For example, some ACPI code seems to use KERN_CONT _together_ with a log
level, and now uses both the KERN_CONT marker and (for example) a
KERN_INFO marker to show that it's an informational continuation of a
line.

Which is actually not a bad idea - if the continuation line cannot be
attached to its predecessor, without the log level information we don't
know what log level to assign to it (and we traditionally just assigned
it the default loglevel).  So having both a log level and the KERN_CONT
marker is not necessarily a bad idea, but it does mean that we need to
actually iterate over potentially multiple markers, rather than just a
single one.

Also, since KERN_CONT was still conceptually needed, and encouraged, but
didn't actually _do_ anything, we've also had the reverse problem:
rather than having too many annotations it has too few, and there is bit
rot with code that no longer marks the continuation lines with the
KERN_CONT marker.

So this patch not only re-instates the non-empty KERN_CONT marker, it
also fixes up the cases of bit-rot I noticed in my own logs.

There are probably other cases where KERN_CONT will be needed to be
added, either because it is new code that never dealt with the need for
KERN_CONT, or old code that has bitrotted without anybody noticing.

That said, we should strive to avoid the need for KERN_CONT.  It does
result in real problems for logging, and should generally not be seen as
a good feature.  If we some day can get rid of the feature entirely,
because nobody does any fragmented printk calls, that would be lovely.

But until that point, let's at mark the code that relies on the hacky
multi-fragment kernel printk's.  Not only does it avoid the ambiguity,
it also annotates code as "maybe this would be good to fix some day".

(That said, particularly during single-threaded bootup, the downsides of
KERN_CONT are very limited.  Things get much hairier when you have
multiple threads going on and user level reading and writing logs too).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-09 12:23:38 -07:00
Adam Borowski fadb424408 vt: Emulate \e[100-107m (bright background colors).
For now, these fall back to regular (dark) colors.

It'd be tempting to replace blink with bright backgrounds, as permitted by
CGA/VGA -- we already muck with the other programmable bit (foreground
brightness vs 512 character font).  This would bring vgacon in line with
fbcon, which doesn't support blink anywhere but on some drivers renders
that bit as bright background.  If that is done, this commit should be
amended to be one of ways of setting that bit.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-22 11:41:54 +02:00
Adam Borowski cc67dc28b3 vt: Support \e[90-97m (bright foreground colors).
These codes are supported by all major terminals, thus they occasionally see
some use despite being redundant with \e[38;5;(x+8)m or (less exactly)
\e[1;3(x)m.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-22 11:41:54 +02:00
Adam Borowski 3e7ec4a0e6 vt: Drop a no longer true comment.
Some guy went on a patching spree, adding 24-bit colour support all around:
https://gist.github.com/XVilka/8346728

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-22 11:41:54 +02:00
Adam Borowski 0bf1f4a8a3 vt: Make a comparison <= for readability.
All other uses of vc_npar are inclusive (save for < NPAR) which raises
eyebrows, so let's at least do so consistently.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-22 11:41:54 +02:00
Adam Borowski 669e0a51b1 vt: Fix a read-past-array in vc_t416_color().
This makes it show up on UBSAN:
perl -e 'for (0..15) {my @x=("0")x$_;push @x,qw(38 2 64 128 192 4);printf
"\e[%smAfter %d zeroes.\e[0m\n", join(";",@x[0..($_+5<15?$_+5:15)]), $_}'

Seems harmless: if you can programmatically read attributes of a vt
character (/dev/vcsa*), multiple probes can obtain parts of vt_mode then
lowest byte (5th on 64-bit big-endian) of a pointer.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-22 11:41:54 +02:00
Tejun Heo 1bb0802460 tty, workqueue: remove keventd_up() usage
Now that workqueue can handle work item queueing from very early
during boot, there is no need to delay schedule_work() while
!keventd_up().  Remove it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
2016-09-17 13:18:21 -04:00
Linus Torvalds 721413aff2 TTY/Serial driver update for 4.8-rc1
Here is the big tty and serial driver update for 4.8-rc1.
 
 Lots of good cleanups from Jiri on a number of vt and other tty related
 things, and the normal driver updates.  Full details are in the
 shortlog.
 
 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-4.8-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 tty and serial driver update for 4.8-rc1.

  Lots of good cleanups from Jiri on a number of vt and other tty
  related things, and the normal driver updates.  Full details are in
  the shortlog.

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

* tag 'tty-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (90 commits)
  tty/serial: atmel: enforce tasklet init and termination sequences
  serial: sh-sci: Stop transfers in sci_shutdown()
  serial: 8250_ingenic: drop #if conditional surrounding earlycon code
  serial: 8250_mtk: drop !defined(MODULE) conditional
  serial: 8250_uniphier: drop !defined(MODULE) conditional
  earlycon: mark earlycon code as __used iif the caller is built-in
  tty/serial/8250: use mctrl_gpio helpers
  serial: mctrl_gpio: enable API usage only for initialized mctrl_gpios struct
  serial: mctrl_gpio: add modem control read routine
  tty/serial/8250: make UART_MCR register access consistent
  serial: 8250_mid: Read RX buffer on RX DMA timeout for DNV
  serial: 8250_dma: Export serial8250_rx_dma_flush()
  dmaengine: hsu: Export hsu_dma_get_status()
  tty: serial: 8250: add CON_CONSDEV to flags
  tty: serial: samsung: add byte-order aware bit functions
  tty: serial: samsung: fixup accessors for endian
  serial: sirf: make fifo functions static
  serial: mps2-uart: make driver explicitly non-modular
  serial: mvebu-uart: free the IRQ in ->shutdown()
  serial/bcm63xx_uart: use correct alias naming
  ...
2016-07-24 17:14:37 -07:00
Linus Torvalds 3aa536d9aa Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input fixes from Dmitry Torokhov:
 "A few more fixes for the input subsystem:

   - restore naming for tsc2005 touchscreens as some userspace match on it
   - fix out of bound access in legacy keyboard driver
   - fixup in RMI4 driver

  Everything is tagged for stable as well"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: tsc200x - report proper input_dev name
  tty/vt/keyboard: fix OOB access in do_compute_shiftstate()
  Input: synaptics-rmi4 - fix maximum size check for F12 control register 8
2016-07-23 12:10:48 +09:00
Dmitry Torokhov 510cccb5b0 tty/vt/keyboard: fix OOB access in do_compute_shiftstate()
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 <sasha.levin@oracle.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2016-07-20 17:50:23 -07:00
Greg Kroah-Hartman 67417f9c26 Merge 4.7-rc6 into tty-next
We want the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-07-04 08:17:08 -07:00
David Daney 1b45996d2e tty: vt: Fix soft lockup in fbcon cursor blink timer.
We are getting somewhat random soft lockups with this signature:

[   86.992215] [<fffffc00080935e0>] el1_irq+0xa0/0x10c
[   86.997082] [<fffffc000841822c>] cursor_timer_handler+0x30/0x54
[   87.002991] [<fffffc000810ec44>] call_timer_fn+0x54/0x1a8
[   87.008378] [<fffffc000810ef88>] run_timer_softirq+0x1c4/0x2bc
[   87.014200] [<fffffc000809077c>] __do_softirq+0x114/0x344
[   87.019590] [<fffffc00080af45c>] irq_exit+0x74/0x98
[   87.024458] [<fffffc00080fac20>] __handle_domain_irq+0x98/0xfc
[   87.030278] [<fffffc000809056c>] 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 <david.daney@cavium.com>
Cc: stable@vger.kernel.org
Acked-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Scot Doyle <lkml14@scotdoyle.com>
Tested-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25 10:41:13 -07:00
Muhammad Falak R Wani 9b6519009d tty/vt/keyboard: use memdup_user().
Use memdup_user to duplicate a memory region from user-space to
kernel-space, instead of open coding using kmalloc & copy_from_user.

Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25 10:40:33 -07:00
Jiri Slaby abd530de2a tty: vt, remove unused vc_deccolm
vc_deccolm is only set and never read, remove the member from vc_data.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25 09:04:48 -07:00