linux/kernel/printk.c, branch v2.6.24

[SERIAL]: Fix section mismatches in Sun serial console drivers.

2007-12-29T09:19:49Z

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

serial: turn serial console suspend a boot rather than compile time option

2007-10-18T21:37:19Z

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 Acked-by: "Rafael J. Wysocki" Acked-by: Pavel Machek Cc: Nigel Cunningham Cc: Russell King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

printk: add interfaces for external access to the log buffer

2007-10-17T15:42:50Z

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 Cc: Robin Getz Cc: Greg Ungerer Cc: Russell King Cc: Paul Mundt Acked-by: Tim Bird Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

slow down printk during boot

2007-10-16T16:42:49Z

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 Signed-off-by: Dave Jones Signed-off-by: Adrian Bunk Signed-off-by: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fix - ensure we don't use bootconsoles after init has been released

2007-08-22T03:23:53Z

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 Signed-off-by: Linus Torvalds

ensure we don't use bootconsoles after init has been released

2007-08-21T05:42:01Z

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 Acked-by: Gerd Hoffmann Acked-by: Paul Mundt Cc: Mike Frysinger Signed-off-by: Linus Torvalds

serial: fix 8250 early console setup

2007-08-03T22:02:56Z

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 Cc: Yinghai Lu Signed-off-by: Linus Torvalds

kernel/printk.c: document possible deadlock against scheduler

2007-07-16T16:05:52Z

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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

add printk.time option, deprecate 'time'

2007-07-16T16:05:45Z

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= 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

serial: convert early_uart to earlycon for 8250

2007-07-16T16:05:35Z

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: Cc: Andi Kleen Cc: Bjorn Helgaas Cc: Russell King Cc: Gerd Hoffmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds