From a8cfdc68f6cfc0c7ffc6d664406fe7f06f17eef4 Mon Sep 17 00:00:00 2001 From: Olof Johansson Date: Mon, 12 Dec 2016 16:45:56 -0800 Subject: [PATCH] printk: add Kconfig option to set default console loglevel Add a configuration option to set the default console loglevel. This is, as before, still possible to override at runtime through bootargs (loglevel=), sysrq and /proc/printk. There are cases where adding additional arguments on the commandline is impractical, and changing the default for the kernel when being built makes more sense. Provide such a method here, for those who choose to do so. Also, while touching this code, clarify the difference between MESSAGE_LOGLEVEL_DEFAULT and CONSOLE_LOGLEVEL_DEFAULT. Link: http://lkml.kernel.org/r/1479676829-30031-1-git-send-email-olof@lixom.net Signed-off-by: Olof Johansson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/printk.h | 7 ++++++- lib/Kconfig.debug | 19 +++++++++++++++++++ 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/include/linux/printk.h b/include/linux/printk.h index afe8ccec1672..3472cc6b7a60 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -50,10 +50,15 @@ static inline const char *printk_skip_headers(const char *buffer) #define CONSOLE_LOGLEVEL_SILENT 0 /* Mum's the word */ #define CONSOLE_LOGLEVEL_MIN 1 /* Minimum loglevel we let people use */ #define CONSOLE_LOGLEVEL_QUIET 4 /* Shhh ..., when booted with "quiet" */ -#define CONSOLE_LOGLEVEL_DEFAULT 7 /* anything MORE serious than KERN_DEBUG */ #define CONSOLE_LOGLEVEL_DEBUG 10 /* issue debug messages */ #define CONSOLE_LOGLEVEL_MOTORMOUTH 15 /* You can't shut this one up */ +/* + * Default used to be hard-coded at 7, we're now allowing it to be set from + * kernel config. + */ +#define CONSOLE_LOGLEVEL_DEFAULT CONFIG_CONSOLE_LOGLEVEL_DEFAULT + extern int console_printk[]; #define console_loglevel (console_printk[0]) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 9bb7d825ba14..65a619e0ad5d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -15,6 +15,21 @@ config PRINTK_TIME The behavior is also controlled by the kernel command line parameter printk.time=1. See Documentation/kernel-parameters.txt +config CONSOLE_LOGLEVEL_DEFAULT + int "Default console loglevel (1-15)" + range 1 15 + default "7" + help + Default loglevel to determine what will be printed on the console. + + Setting a default here is equivalent to passing in loglevel= in + the kernel bootargs. loglevel= continues to override whatever + value is specified here as well. + + Note: This does not affect the log level of un-prefixed prink() + usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT + option. + config MESSAGE_LOGLEVEL_DEFAULT int "Default message log level (1-7)" range 1 7 @@ -26,6 +41,10 @@ config MESSAGE_LOGLEVEL_DEFAULT that are auditing their logs closely may want to set it to a lower priority. + Note: This does not affect what message level gets printed on the console + by default. To change that, use loglevel= in the kernel bootargs, + or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. + config BOOT_PRINTK_DELAY bool "Delay each boot printk message by N milliseconds" depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY -- 2.20.1