* 'core/printk' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, generic: mark early_printk as asmlinkage
printk: export console_drivers
printk: remember the message level for multi-line output
printk: refactor processing of line severity tokens
printk: don't prefer unsuited consoles on registration
printk: clean up recursion check related static variables
namespacecheck: more kernel/printk.c fixes
namespacecheck: fix kernel printk.c
It's not explicitly marked as asmlinkage, but invoked from x86_32
startup code with parameters on stack.
No other architectures define early_printk and none of them are affected
by this change, since defines asmlinkage as empty token.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Without console= arguments on the kernel command line, the first
console to register becomes enabled and the preferred console (the one
behind /dev/console). This is normally tty (assuming
CONFIG_VT_CONSOLE is enabled, which it commonly is).
This is okay as long tty is a useful console. But unless we have the
PV framebuffer, and it is enabled for this domain, tty0 in domU is
merely a dummy. In that case, we want the preferred console to be the
Xen console hvc0, and we want it without having to fiddle with the
kernel command line. Commit b8c2d3dfbc
did that for us.
Since we now have the PV framebuffer, we want to enable and prefer tty
again, but only when PVFB is enabled. But even then we still want to
enable the Xen console as well.
Problem: when tty registers, we can't yet know whether the PVFB is
enabled. By the time we can know (xenstore is up), the console setup
game is over.
Solution: enable console tty by default, but keep hvc as the preferred
console. Change the preferred console to tty when PVFB probes
successfully, unless we've been given console kernel parameters.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
printk(KERN_ALERT "Danger Will Robinson!\nAlien Approaching!\n");
At present this will result in one message at ALERT level and one
at the current default message loglevel (e.g. WARNING). This is
non-intuitive.
Modify vprintk() to remember the message loglevel each time it
is specified and use it for subsequent lines of output which do
not specify one, within the same call to printk.
Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Restructure the logic of vprintk() so the processing of the leading
3 characters of each input line is in one place, regardless whether
printk_time is enabled. This makes the code smaller and easier to
understand.
size reduction in kernel/printk.o:
text data bss dec hex filename
6157 397 1049804 1056358 101e66 printk.o.before
6117 397 1049804 1056318 101e3e printk.o.after
and some style uncleanlinesses removed as well as a side-effect:
Before:
total: 19 errors, 22 warnings, 1340 lines checked
After:
total: 17 errors, 22 warnings, 1333 lines checked
Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
console election: If some console happens to be registered first which does
not provide a tty binding (!console->device), it prevents that more suited
consoles which are registered later on can enter the candidate pool for
console_device(). This is observable with KGDB's console which may already
be registered (and exploited!) during early debugger connections, that is
before any regular console registration.
This patch fixes the issue by postponing the final, automated
preferred_console selection until someone with a non-NULL device handler
comes around.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Make printk_recursion_bug_msg static and drop printk prefix from recursion
variables.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This adds a minimalistic braille screen reader support. This is meant to
be used by blind people e.g. on boot failures or when / cannot be mounted
etc and thus the userland screen readers can not work.
[akpm@linux-foundation.org: fix exports]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Jiri Kosina <jikos@jikos.cz>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Operations are now a shared const function block as with most other Linux
objects
- Introduce wrappers for some optional functions to get consistent behaviour
- Wrap put_char which used to be patched by the tty layer
- Document which functions are needed/optional
- Make put_char report success/fail
- Cache the driver->ops pointer in the tty as tty->ops
- Remove various surplus lock calls we no longer need
- Remove proc_write method as noted by Alexey Dobriyan
- Introduce some missing sanity checks where certain driver/ldisc
combinations would oops as they didn't check needed methods were present
[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When I cleaned up printk() and split up the printk locking logic in
commit 266c2e0abe ("Make printk() console
semaphore accesses sensible") I had incorrectly moved the call to
have_callable_console() outside of the console semaphore.
That was buggy. The console semaphore protects the console_drivers list
that is used by have_callable_console().
Thanks go to Bongani Hlope who saw this as a hang on shutdown and reboot
and bisected the bug to the right commit, and tested this patch. See
http://lkml.org/lkml/2008/4/11/315
Bisected-and-tested-by: Bongani Hlope <bonganilinux@mweb.co.za>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The printk() logic on when/how to get the console semaphore was
unreadable, this splits the code up into a few helper functions and
makes it easier to follow what is going on.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
printk recursion detection prepends message to printk_buf and offsets
printk_buf when actual message is printed but it forgets to trim buffer
length accordingly. This can result in overrun in extreme cases. Fix it.
[ mingo@elte.hu:
bug was introduced by me via:
commit 32a7600668
Author: Ingo Molnar <mingo@elte.hu>
Date: Fri Jan 25 21:07:58 2008 +0100
printk: make printk more robust by not allowing recursion
]
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
