linux-toradex.git/drivers/tty/vt/vt.c, branch v3.10.41

vt: Fix secure clear screen

2014-02-22T20:41:27+00:00

commit 0930b0950a8996aa88b0d2ba4bb2bab27cc36bc7 upstream.

\E[3J console code (secure clear screen) needs to update_screen(vc)
in order to write-through blanks into off-screen video memory.

This has been removed accidentally in 3.6 by:

commit 81732c3b2fede049a692e58a7ceabb6d18ffb18c
Author: Jean-François Moine 
Date:   Thu Sep 6 19:24:13 2012 +0200

    tty vt: Fix line garbage in virtual console on command line edition

Signed-off-by: Petr Písař 
Signed-off-by: Greg Kroah-Hartman

tty/vt: Fix vc_deallocate() lock order

2013-05-20T19:15:59+00:00

Now that the tty port owns the flip buffers and i/o is allowed
from the driver even when no tty is attached, the destruction
of the tty port (and the flip buffers) must ensure that no
outstanding work is pending.

Unfortunately, this creates a lock order problem with the
console_lock (see attached lockdep report [1] below).

For single console deallocation, drop the console_lock prior
to port destruction. When multiple console deallocation,
defer port destruction until the consoles have been
deallocated.

tty_port_destroy() is not required if the port has not
been used; remove from vc_allocate() failure path.

[1] lockdep report from Dave Jones 

 ======================================================
 [ INFO: possible circular locking dependency detected ]
 3.9.0+ #16 Not tainted
 -------------------------------------------------------
 (agetty)/26163 is trying to acquire lock:
 blocked:  ((&buf->work)){+.+...}, instance: ffff88011c8b0020, at: [] flush_work+0x5/0x2e0

 but task is already holding lock:
 blocked:  (console_lock){+.+.+.}, instance: ffffffff81c2fde0, at: [] vt_ioctl+0xb61/0x1230

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (console_lock){+.+.+.}:
        [] lock_acquire+0xa4/0x210
        [] console_lock+0x77/0x80
        [] con_flush_chars+0x2d/0x50
        [] n_tty_receive_buf+0x122/0x14d0
        [] flush_to_ldisc+0x119/0x170
        [] process_one_work+0x211/0x700
        [] worker_thread+0x11b/0x3a0
        [] kthread+0xed/0x100
        [] ret_from_fork+0x7c/0xb0

 -> #0 ((&buf->work)){+.+...}:
        [] __lock_acquire+0x193a/0x1c00
        [] lock_acquire+0xa4/0x210
        [] flush_work+0x4e/0x2e0
        [] __cancel_work_timer+0x95/0x130
        [] cancel_work_sync+0x10/0x20
        [] tty_port_destroy+0x12/0x20
        [] vc_deallocate+0xf8/0x110
        [] vt_ioctl+0xb6c/0x1230
        [] tty_ioctl+0x285/0xd50
        [] do_vfs_ioctl+0x305/0x530
        [] sys_ioctl+0x81/0xa0
        [] system_call_fastpath+0x16/0x1b

 other info that might help us debug this:

 [ 6760.076175]  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(console_lock);
                                lock((&buf->work));
                                lock(console_lock);
   lock((&buf->work));

  *** DEADLOCK ***

 1 lock on stack by (agetty)/26163:
  #0: blocked:  (console_lock){+.+.+.}, instance: ffffffff81c2fde0, at: [] vt_ioctl+0xb61/0x1230
 stack backtrace:
 Pid: 26163, comm: (agetty) Not tainted 3.9.0+ #16
 Call Trace:
  [] print_circular_bug+0x200/0x20e
  [] __lock_acquire+0x193a/0x1c00
  [] ? sched_clock+0x9/0x10
  [] ? sched_clock+0x9/0x10
  [] ? native_sched_clock+0x20/0x80
  [] lock_acquire+0xa4/0x210
  [] ? flush_work+0x5/0x2e0
  [] flush_work+0x4e/0x2e0
  [] ? flush_work+0x5/0x2e0
  [] ? mark_held_locks+0xbb/0x140
  [] ? __free_pages_ok.part.57+0x93/0xc0
  [] ? mark_held_locks+0xbb/0x140
  [] ? __cancel_work_timer+0x82/0x130
  [] __cancel_work_timer+0x95/0x130
  [] cancel_work_sync+0x10/0x20
  [] tty_port_destroy+0x12/0x20
  [] vc_deallocate+0xf8/0x110
  [] vt_ioctl+0xb6c/0x1230
  [] ? lock_release_holdtime.part.30+0xa1/0x170
  [] tty_ioctl+0x285/0xd50
  [] ? inode_has_perm.isra.46.constprop.61+0x56/0x80
  [] do_vfs_ioctl+0x305/0x530
  [] ? selinux_file_ioctl+0x5b/0x110
  [] sys_ioctl+0x81/0xa0
  [] system_call_fastpath+0x16/0x1b

Cc: Dave Jones 
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux

2013-02-26T00:46:44+00:00

Pull drm merge from Dave Airlie:
 "Highlights:

   - TI LCD controller KMS driver

   - TI OMAP KMS driver merged from staging

   - drop gma500 stub driver

   - the fbcon locking fixes

   - the vgacon dirty like zebra fix.

   - open firmware videomode and hdmi common code helpers

   - major locking rework for kms object handling - pageflip/cursor
     won't block on polling anymore!

   - fbcon helper and prime helper cleanups

   - i915: all over the map, haswell power well enhancements, valleyview
     macro horrors cleaned up, killing lots of legacy GTT code,

   - radeon: CS ioctl unification, deprecated UMS support, gpu reset
     rework, VM fixes

   - nouveau: reworked thermal code, external dp/tmds encoder support
     (anx9805), fences sleep instead of polling,

   - exynos: all over the driver fixes."

Lovely conflict in radeon/evergreen_cs.c between commit de0babd60d8d
("drm/radeon: enforce use of radeon_get_ib_value when reading user cmd")
and the new changes that modified that evergreen_dma_cs_parse()
function.

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (508 commits)
  drm/tilcdc: only build on arm
  drm/i915: Revert hdmi HDP pin checks
  drm/tegra: Add list of framebuffers to debugfs
  drm/tegra: Fix color expansion
  drm/tegra: Split DC_CMD_STATE_CONTROL register write
  drm/tegra: Implement page-flipping support
  drm/tegra: Implement VBLANK support
  drm/tegra: Implement .mode_set_base()
  drm/tegra: Add plane support
  drm/tegra: Remove bogus tegra_framebuffer structure
  drm: Add consistency check for page-flipping
  drm/radeon: Use generic HDMI infoframe helpers
  drm/tegra: Use generic HDMI infoframe helpers
  drm: Add EDID helper documentation
  drm: Add HDMI infoframe helpers
  video: Add generic HDMI infoframe helpers
  drm: Add some missing forward declarations
  drm: Move mode tables to drm_edid.c
  drm: Remove duplicate drm_mode_cea_vic()
  gma500: Fix n, m1 and m2 clock limits for sdvo and lvds
  ...

tty vt: fix character insertion overflow

2013-02-25T01:29:49+00:00

Commit 81732c3b2fed ("tty vt: Fix line garbage in virtual console on
command line edition") broke insert_char() in multiple ways.  Then
commit b1a925f44a3a ("tty vt: Fix a regression in command line edition")
partially fixed it.  However, the buffer being moved is still too large
and overflowing beyond the end of the current line, corrupting existing
characters on the next line.

Example test case:

echo -e "abc\nde\x1b[A\x1b[4h \x1b[4l\x1b[B"

Expected result:

ab c
de

Current result:

ab c
 e

Needless to say that this is very annoying when inserting words in the
middle of paragraphs with certain text editors.

Signed-off-by: Nicolas Pitre 
Cc: Jean-François Moine 
Cc: Greg Kroah-Hartman 
Cc: 
Signed-off-by: Linus Torvalds

Merge branch 'console-fixes' into drm-next

2013-02-08T02:13:43+00:00

(not the fbcon maintainer pull 2)

fix bug in vgacon on bootup and fbcon losing fonts on startup.

* console-fixes: (50 commits)
  fbcon: don't lose the console font across generic->chip driver switch
  vgacon/vt: clear buffer attributes when we load a 512 character font (v2)

fb: Yet another band-aid for fixing lockdep mess

2013-02-08T02:02:41+00:00

I've still got lockdep warnings even after Alan's patch, and it seems that
yet more band aids are required to paper over similar paths for
unbind_con_driver() and unregister_con_driver().  After this hack, lockdep
warnings are finally gone.

Signed-off-by: Takashi Iwai 
Cc: Alan Cox 
Cc: Florian Tobias Schandinat 
Cc: Jiri Kosina 
Cc: stable 
Tested-by: Sedat Dilek 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Airlie

fb: rework locking to fix lock ordering on takeover

2013-02-08T02:02:40+00:00

Adjust the console layer to allow a take over call where the caller
already holds the locks.  Make the fb layer lock in order.

This is partly a band aid, the fb layer is terminally confused about the
locking rules it uses for its notifiers it seems.

[akpm@linux-foundation.org: remove stray non-ascii char, tidy comment]
[akpm@linux-foundation.org: export do_take_over_console()]
[airlied: cleanup another non-ascii char]
Signed-off-by: Alan Cox 
Cc: Florian Tobias Schandinat 
Cc: Stephen Rothwell 
Cc: Jiri Kosina 
Cc: stable 
Tested-by: Sedat Dilek 
Reviewed-by: Daniel Vetter 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Airlie

vgacon/vt: clear buffer attributes when we load a 512 character font (v2)

2013-02-07T02:37:03+00:00

When we switch from 256->512 byte font rendering mode, it means the
current contents of the screen is being reinterpreted. The bit that holds
the high bit of the 9-bit font, may have been previously set, and thus
the new font misrenders.

The problem case we see is grub2 writes spaces with the bit set, so it
ends up with data like 0x820, which gets reinterpreted into 0x120 char
which the font translates into G with a circumflex. This flashes up on
screen at boot and is quite ugly.

A current side effect of this patch though is that any rendering on the
screen changes color to a slightly darker color, but at least the screen
no longer corrupts.

v2: as suggested by hpa, always clear the attribute space, whether we
are are going to or from 512 chars.

Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie

TTY: switch tty_schedule_flip

2013-01-16T06:43:15+00:00

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

This is the last one: tty_schedule_flip

Signed-off-by: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

TTY: switch tty_insert_flip_char

2013-01-16T06:21:36+00:00

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

tty_insert_flip_char is the next one to proceed. This one is used all
over the code, so the patch is huge.

Signed-off-by: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman