From 346e15beb5343c2eb8216d820f2ed8f150822b08 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Tue, 12 Aug 2008 16:46:19 -0400 Subject: driver core: basic infrastructure for per-module dynamic debug messages Base infrastructure to enable per-module debug messages. I've introduced CONFIG_DYNAMIC_PRINTK_DEBUG, which when enabled centralizes control of debugging statements on a per-module basis in one /proc file, currently, /dynamic_printk/modules. When, CONFIG_DYNAMIC_PRINTK_DEBUG, is not set, debugging statements can still be enabled as before, often by defining 'DEBUG' for the proper compilation unit. Thus, this patch set has no affect when CONFIG_DYNAMIC_PRINTK_DEBUG is not set. The infrastructure currently ties into all pr_debug() and dev_dbg() calls. That is, if CONFIG_DYNAMIC_PRINTK_DEBUG is set, all pr_debug() and dev_dbg() calls can be dynamically enabled/disabled on a per-module basis. Future plans include extending this functionality to subsystems, that define their own debug levels and flags. Usage: Dynamic debugging is controlled by the debugfs file, /dynamic_printk/modules. This file contains a list of the modules that can be enabled. The format of the file is as follows: . . . : Name of the module in which the debug call resides : whether the messages are enabled or not For example: snd_hda_intel enabled=0 fixup enabled=1 driver enabled=0 Enable a module: $echo "set enabled=1 " > dynamic_printk/modules Disable a module: $echo "set enabled=0 " > dynamic_printk/modules Enable all modules: $echo "set enabled=1 all" > dynamic_printk/modules Disable all modules: $echo "set enabled=0 all" > dynamic_printk/modules Finally, passing "dynamic_printk" at the command line enables debugging for all modules. This mode can be turned off via the above disable command. [gkh: minor cleanups and tweaks to make the build work quietly] Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman --- lib/Kconfig.debug | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'lib/Kconfig.debug') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index aa81d284844..31d784dd80d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -807,6 +807,61 @@ menuconfig BUILD_DOCSRC Say N if you are unsure. +config DYNAMIC_PRINTK_DEBUG + bool "Enable dynamic printk() call support" + default n + depends on PRINTK + select PRINTK_DEBUG + help + + Compiles debug level messages into the kernel, which would not + otherwise be available at runtime. These messages can then be + enabled/disabled on a per module basis. This mechanism implicitly + enables all pr_debug() and dev_dbg() calls. The impact of this + compile option is a larger kernel text size of about 2%. + + Usage: + + Dynamic debugging is controlled by the debugfs file, + dynamic_printk/modules. This file contains a list of the modules that + can be enabled. The format of the file is the module name, followed + by a set of flags that can be enabled. The first flag is always the + 'enabled' flag. For example: + + + . + . + . + + : Name of the module in which the debug call resides + : whether the messages are enabled or not + + From a live system: + + snd_hda_intel enabled=0 + fixup enabled=0 + driver enabled=0 + + Enable a module: + + $echo "set enabled=1 " > dynamic_printk/modules + + Disable a module: + + $echo "set enabled=0 " > dynamic_printk/modules + + Enable all modules: + + $echo "set enabled=1 all" > dynamic_printk/modules + + Disable all modules: + + $echo "set enabled=0 all" > dynamic_printk/modules + + Finally, passing "dynamic_printk" at the command line enables + debugging for all modules. This mode can be turned off via the above + disable command. + source "samples/Kconfig" source "lib/Kconfig.kgdb" -- cgit v1.2.3