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* printk: fix comment for printk ratelimitingUwe Kleine-König2008-07-301-4/+4
| | | | | | | | | | The comment assumed the burst to be one and the ratelimit used to be named printk_ratelimit_jiffies. Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com> Cc: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk ratelimiting rewriteDave Young2008-07-251-14/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | All ratelimit user use same jiffies and burst params, so some messages (callbacks) will be lost. For example: a call printk_ratelimit(5 * HZ, 1) b call printk_ratelimit(5 * HZ, 1) before the 5*HZ timeout of a, then b will will be supressed. - rewrite __ratelimit, and use a ratelimit_state as parameter. Thanks for hints from andrew. - Add WARN_ON_RATELIMIT, update rcupreempt.h - remove __printk_ratelimit - use __ratelimit in net_ratelimit Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* swsusp: provide users with a hint about the no_console_suspend optionPavel Machek2008-07-241-1/+1
| | | | | | | | | | | Tell the user about the no_console_suspend option, so that we don't have to tell each bug reporter personally. [akpm@linux-foundation.org: clarify the text a little] Signed-off-by: Pavel Machek <pavel@suse.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'core/printk' of ↵Linus Torvalds2008-07-141-62/+43
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * '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
| * x86, generic: mark early_printk as asmlinkageJiri Slaby2008-06-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * printk: export console_driversIngo Molnar2008-06-161-0/+2
| | | | | | | | | | | | this symbol is needed by drivers/video/xen-fbfront.ko. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * printk: remember the message level for multi-line outputNick Andrew2008-05-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * printk: refactor processing of line severity tokensNick Andrew2008-05-241-34/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * printk: don't prefer unsuited consoles on registrationJan Kiszka2008-05-241-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * printk: clean up recursion check related static variablesTejun Heo2008-05-241-12/+10
| | | | | | | | | | | | | | | | | | 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>
| * namespacecheck: more kernel/printk.c fixesThomas Gleixner2008-05-241-13/+0
| | | | | | | | | | | | | | [ Stephen Rothwell <sfr@canb.auug.org.au>: build fix ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * namespacecheck: fix kernel printk.cThomas Gleixner2008-05-241-2/+2
| | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'auto-ftrace-next' into tracing/for-linusIngo Molnar2008-07-141-0/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/entry_32.S arch/x86/kernel/process_32.c arch/x86/kernel/process_64.c arch/x86/lib/Makefile include/asm-x86/irqflags.h kernel/Makefile kernel/sched.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * \ Merge branch 'tracing/ftrace' into auto-ftrace-nextIngo Molnar2008-07-101-0/+2
| |\ \
| | * | ftrace: trace irq disabled critical timingsSteven Rostedt2008-05-231-0/+2
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds latency tracing for critical timings (how long interrupts are disabled for). "irqsoff" is added to /debugfs/tracing/available_tracers Note: tracing_max_latency also holds the max latency for irqsoff (in usecs). (default to large number so one must start latency tracing) tracing_thresh threshold (in usecs) to always print out if irqs off is detected to be longer than stated here. If irq_thresh is non-zero, then max_irq_latency is ignored. Here's an example of a trace with ftrace_enabled = 0 ======= preemption latency trace v1.1.5 on 2.6.24-rc7 Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 100 us, #3/3, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- => started at: _spin_lock_irqsave+0x2a/0xb7 => ended at: _spin_unlock_irqrestore+0x32/0x5f _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 1d.s3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000]) swapper-0 1d.s3 100us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1d.s3 100us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f) vim:ft=help ======= And this is a trace with ftrace_enabled == 1 ======= preemption latency trace v1.1.5 on 2.6.24-rc7 -------------------------------------------------------------------- latency: 102 us, #12/12, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- => started at: _spin_lock_irqsave+0x2a/0xb7 => ended at: _spin_unlock_irqrestore+0x32/0x5f _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 1dNs3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000]) swapper-0 1dNs3 46us : e1000_read_phy_reg+0x16/0x225 [e1000] (e1000_update_stats+0x5e2/0x64c [e1000]) swapper-0 1dNs3 46us : e1000_swfw_sync_acquire+0x10/0x99 [e1000] (e1000_read_phy_reg+0x49/0x225 [e1000]) swapper-0 1dNs3 46us : e1000_get_hw_eeprom_semaphore+0x12/0xa6 [e1000] (e1000_swfw_sync_acquire+0x36/0x99 [e1000]) swapper-0 1dNs3 47us : __const_udelay+0x9/0x47 (e1000_read_phy_reg+0x116/0x225 [e1000]) swapper-0 1dNs3 47us+: __delay+0x9/0x50 (__const_udelay+0x45/0x47) swapper-0 1dNs3 97us : preempt_schedule+0xc/0x84 (__delay+0x4e/0x50) swapper-0 1dNs3 98us : e1000_swfw_sync_release+0xc/0x55 [e1000] (e1000_read_phy_reg+0x211/0x225 [e1000]) swapper-0 1dNs3 99us+: e1000_put_hw_eeprom_semaphore+0x9/0x35 [e1000] (e1000_swfw_sync_release+0x50/0x55 [e1000]) swapper-0 1dNs3 101us : _spin_unlock_irqrestore+0xe/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1dNs3 102us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1dNs3 102us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f) vim:ft=help ======= Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'linus' into x86/coreIngo Molnar2008-07-121-1/+1
|\ \ \ | |/ / | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/mm/ioremap.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | kernel/printk.c: Made printk_recursion_bug_msg static.Daniel Guilak2008-07-081-1/+1
| |/ | | | | | | | | | | Signed-off-by: Daniel Guilak <daniel@danielguilak.com> Acked-by: Josh Triplett <josh@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | printk: export console_driversIngo Molnar2008-07-081-0/+2
| | | | | | | | | | | | | | | | this symbol is needed by drivers/video/xen-fbfront.ko. [ cherry-picked from tip/core/printk ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | xen: Enable console tty by default in domU if it's not a dummyMarkus Armbruster2008-05-271-0/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 b8c2d3dfbc117dff26058fbac316b8acfc2cb5f7 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: don't read beyond string arguments' terminating zeroMarkus Armbruster2008-04-301-1/+1
| | | | | | | | | Fix update_console_cmdline() not to to read beyond the terminating zero of its name argument. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Basic braille screen reader supportSamuel Thibault2008-04-301-24/+66
| | | | | | | | | | | | | | | 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>
* tty: The big operations reworkAlan Cox2008-04-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - 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>
* isolate ratelimit from printk.c for other useDave Young2008-04-291-25/+1
| | | | | | | | | | | | Due to the rcupreempt.h WARN_ON trigged, I got 2G syslog file. For some serious complaining of kernel, we need repeat the warnings, so here I isolate the ratelimit part of printk.c to a standalone file. Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix locking bug in "acquire_console_semaphore_for_printk()"Linus Torvalds2008-04-151-2/+15
| | | | | | | | | | | | | | | | | | | When I cleaned up printk() and split up the printk locking logic in commit 266c2e0abeca649fa6667a1a427ad1da507c6375 ("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>
* Make printk() console semaphore accesses sensibleLinus Torvalds2008-03-241-35/+48
| | | | | | | | 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: fix possible printk overrunTejun Heo2008-02-261-1/+1
| | | | | | | | | | | | | | | | | | | | | 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 32a76006683f7b28ae3cc491da37716e002f198e 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>
* printk_ratelimit() functions should use CONFIG_PRINTKJoe Perches2008-02-081-0/+2
| | | | | | | | Makes an embedded image a bit smaller. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* The scheduled 'time' option removalAdrian Bunk2008-02-081-13/+0
| | | | | | | | | The scheduled removal of the 'time' option. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Nuke duplicate include from printk.cJesper Juhl2008-02-081-1/+0
| | | | | | | | Remove the duplicate inclusion of linux/jiffies.h from kernel/printk.c Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk.c: use unsigned ints instead of longs for logbuf indexDenys Vlasenko2008-02-061-18/+18
| | | | | | | | | | | | | | | | Stop using unsigned _longs_ for printk buffer indexes. Log buffer is way smaller than 2 gigabytes and unsigned ints will work too . Indeed, they do work nicely on all 32-bit platforms where longs and ints are the same. With this patch, we have following size savings on amd64: text data bss dec hex filename 5997 313 17736 24046 5dee 2.6.23.1.t64/kernel/printk.o 5858 313 17700 23871 5d3f 2.6.23.1.printk.t64/kernel/printk.o Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* debug: turn ignore_loglevel into an early paramIngo Molnar2008-01-311-2/+2
| | | | | | | i was debugging early crashes and wondered where all the printks went. The reason: ignore_loglevel_setup() was not called yet ... Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: make early printk selectable on 64-bit as wellIngo Molnar2008-01-301-0/+7
| | | | | | | | | | | | | Enable CONFIG_EMBEDDED to select CONFIG_EARLY_PRINTK on 64-bit as well. saves ~2K: text data bss dec hex filename 7290283 3672091 1907848 12870222 c4624e vmlinux.before 7288373 3671795 1907848 12868016 c459b0 vmlinux.after Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* printk: revert ktime_get() timestampsIngo Molnar2008-01-271-3/+1
| | | | | | | | | | revert 19ef9309273d26cb005cb23e6a370353dca91099. Kevin Winchester reported a lockup during X startup an bisected it to this commit. Reported-by: Kevin Winchester <kjwinchester@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* printk: use ktime_get()Ingo Molnar2008-01-251-1/+3
| | | | | | | | | | | | | printk timestamps: use ktime_get(). Some platforms have a functioning clocksource function only after they are done with early bootup, so delay this until out of SYSTEM_BOOTING state. it's also inherently safe now, as any bugs in this area will be caught by the printk recursion checks. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove printk_clock()Ingo Molnar2008-01-251-5/+0
| | | | | | printk_clock() is obsolete - it has been replaced with cpu_clock(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix CONFIG_PRINT_TIME's reliance on sched_clock()Ingo Molnar2008-01-251-1/+1
| | | | | | | | | | | | | Stefano Brivio reported weird printk timestamp behavior during CPU frequency changes: http://bugzilla.kernel.org/show_bug.cgi?id=9475 fix CONFIG_PRINT_TIME's reliance on sched_clock() and use cpu_clock() instead. Reported-and-bisected-by: Stefano Brivio <stefano.brivio@polimi.it> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* printk: make printk more robust by not allowing recursionIngo Molnar2008-01-251-10/+38
| | | | | | | | | | | | | | | | | make printk more robust by allowing recursion only if there's a crash going on. Also add recursion detection. I've tested it with an artificially injected printk recursion - instead of a lockup or spontaneous reboot or other crash, the output was a well controlled: [ 41.057335] SysRq : <2>BUG: recent printk recursion! [ 41.057335] loglevel0-8 reBoot Crashdump show-all-locks(D) tErm Full kIll saK showMem Nice powerOff showPc show-all-timers(Q) unRaw Sync showTasks Unmount shoW-blocked-tasks also do all this printk-debug logic with irqs disabled. Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Nick Piggin <npiggin@suse.de>
* [SERIAL]: Fix section mismatches in Sun serial console drivers.David S. Miller2007-12-291-1/+1
| | | | | | | | | | | | | | | | | | | We're exporting an __init function, oops :-) The core issue here is that add_preferred_console() is marked as __init, this makes it impossible to invoke this thing from a driver probe routine which is what the Sparc serial drivers need to do. There is no harm in dropping the __init marker. This code will actually work properly when invoked from a modular driver, except that init will probably not pick up the console change without some other support code. Then we can drop the __init from sunserial_console_match() and we're no longer exporting an __init function to modules. Signed-off-by: David S. Miller <davem@davemloft.net>
* serial: turn serial console suspend a boot rather than compile time optionAndres Salomon2007-10-181-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, there's a CONFIG_DISABLE_CONSOLE_SUSPEND that allows one to stop the serial console from being suspended when the rest of the machine goes to sleep. This is incredibly useful for debugging power management-related things; however, having it as a compile-time option has proved to be incredibly inconvenient for us (OLPC). There are plenty of times that we want serial console to not suspend, but for the most part we'd like serial console to be suspended. This drops CONFIG_DISABLE_CONSOLE_SUSPEND, and replaces it with a kernel boot parameter (no_console_suspend). By default, the serial console will be suspended along with the rest of the system; by passing 'no_console_suspend' to the kernel during boot, serial console will remain alive during suspend. For now, this is pretty serial console specific; further fixes could be applied to make this work for things like netconsole. Signed-off-by: Andres Salomon <dilinger@debian.org> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@suspend2.net> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk: add interfaces for external access to the log bufferMike Frysinger2007-10-171-0/+52
| | | | | | | | | | | | | | | | | Add two new functions for reading the kernel log buffer. The intention is for them to be used by recovery/dump/debug code so the kernel log can be easily retrieved/parsed in a crash scenario, but they are generic enough for other people to dream up other fun uses. [akpm@linux-foundation.org: buncha fixes] Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Robin Getz <rgetz@blackfin.uclinux.org> Cc: Greg Ungerer <gerg@snapgear.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: Tim Bird <tim.bird@am.sony.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slow down printk during bootRandy Dunlap2007-10-161-0/+59
| | | | | | | | | | | | | | | | | | | | | | | | | Optionally add a boot delay after each kernel printk() call, crudely measured in milliseconds, with a maximum delay of 10 seconds per printk. Enable CONFIG_BOOT_PRINTK_DELAY=y and then add (e.g.): "lpj=loops_per_jiffy boot_delay=100" to the kernel command line. It has been useful in cases like "during boot, my machine just reboots or the screen goes black" by slowing down printk, (and adding initcall_debug), we can usually see the last thing that happened before the lights went out which is usually a valuable clue. [akpm@linux-foundation.org: not all architectures implement CONFIG_HZ] [akpm@linux-foundation.org: fix lots of stuff] [bunk@stusta.de: kernel/printk.c: make 2 variables static] [heiko.carstens@de.ibm.com: fix slow down printk on boot compile error] Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fix - ensure we don't use bootconsoles after init has been releasedRobin Getz2007-08-211-4/+6
| | | | | | | | | Gerd Hoffmann pointed out that my patch from yesterday can lead to a null pointer dereference if the kernel is booted with no console, and no earlyprintk defined. This fixes that issue. Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ensure we don't use bootconsoles after init has been releasedRobin Getz2007-08-201-0/+11
| | | | | | | | | | | | | | | | | This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=69331af79cf29e26d1231152a172a1a10c2df511 This ensures that a bootconsole is unregistered if it is not replaced. The current implementation spews garbage out the bootconsole in this case, since the bootconsole structure is normally in the init section, and is freed, but still used. Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org> Acked-by: Gerd Hoffmann <kraxel@redhat.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Mike Frysinger <vapier.adi@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* serial: fix 8250 early console setupDaniel Ritz2007-08-031-1/+1
| | | | | | | | | | the early setup function serial8250_console_early_setup() can be called from non __init code (eg. hotpluggable serial ports like serial_cs) so remove the __init from the call chain to avoid crashes. Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch> Cc: Yinghai Lu <yinghai.lu@sun.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/printk.c: document possible deadlock against schedulerJiri Kosina2007-07-161-0/+3
| | | | | | | | | | | | | | | | kernel/printk.c: document possible deadlock against scheduler The printk's comment states that it can be called from every context, which might lead to false illusion that it could be called from everywhere without any restrictions. This is however not true - a call to printk() could deadlock if called from scheduler code (namely from schedule(), wake_up(), etc) on runqueue lock when it tries to wake up klogd. Document this. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* add printk.time option, deprecate 'time'Randy Dunlap2007-07-161-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow printk_time to be enabled or disabled at boot time. Previously it could be enabled only, but not disabled. Change printk_time from an int to a bool since that's what it is. Make its logical (exposed) name just be "time" (was "printk_time"). Note: Changes kernel boot option syntax from "time" to "printk.time=value". Since printk_time is declared as a module_param, it can also be changed at run-time by modifying /sys/module/printk/parameters/time to a value of 1/Y/y to enabled it or 0/N/n to disable it. Since printk_time is declared as a module_param, its value can also be set at boot-time by using linux printk.time=<bool> If the "time" boot option is used, print a message that it is deprecated and will be removed. Note its planned removal in feature-removal-schedule.txt. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* serial: convert early_uart to earlycon for 8250Yinghai Lu2007-07-161-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and include/asm-x86_64/serial.h. the serial8250_ports need to be probed late in serial initializing stage. the console_init=>serial8250_console_init=> register_console=>serial8250_console_setup will return -ENDEV, and console ttyS0 can not be enabled at that time. need to wait till uart_add_one_port in drivers/serial/serial_core.c to call register_console to get console ttyS0. that is too late. Make early_uart to use early_param, so uart console can be used earlier. Make it to be bootconsole with CON_BOOT flag, so can use console handover feature. and it will switch to corresponding normal serial console automatically. new command line will be: console=uart8250,io,0x3f8,9600n8 console=uart8250,mmio,0xff5e0000,115200n8 or earlycon=uart8250,io,0x3f8,9600n8 earlycon=uart8250,mmio,0xff5e0000,115200n8 it will print in very early stage: Early serial console at I/O port 0x3f8 (options '9600n8') console [uart0] enabled later for console it will print: console handover: boot [uart0] -> real [ttyS0] Signed-off-by: <yinghai.lu@sun.com> Cc: Andi Kleen <ak@suse.de> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* console: console handover to preferred consoleYinghai Lu2007-07-161-1/+4
| | | | | | | | | | | | | | | | | | | | | for earlyprintk=ttyS0,9600 console=tty0 console=ttyS0,9600n8 the handover will happen from earlyser0 to tty0. but what we want is to hand over to ttyS0. Later with serial-convert-early_uart-to-earlycon-for-8250.patch, console=tty0 console=uart8250,io,0x3f8,9600n8 will handover to ttyS0 instead of tty0. Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Cc: Andi Kleen <ak@suse.de> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* console: more buf for index parsingYinghai Lu2007-07-161-10/+10
| | | | | | | | | | | | Change name to buf according to the usage as name + index Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Cc: Andi Kleen <ak@suse.de> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* header cleaning: don't include smp_lock.h when not usedRandy Dunlap2007-05-081-1/+0
| | | | | | | | | | | | Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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