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diff --git a/scripts/kconfig/lkc_overview b/scripts/kconfig/lkc_overview new file mode 100644 index 0000000..e9db60e --- a/dev/null +++ b/scripts/kconfig/lkc_overview @@ -0,0 +1,111 @@ +Introduction +------------ + +The configuration database is collection of configuration options +organized in a tree structure: + + +- Code maturity level options + | +- Prompt for development and/or incomplete code/drivers + +- General setup + | +- Networking support + | +- System V IPC + | +- BSD Process Accounting + | +- Sysctl support + +- Loadable module support + | +- Enable loadable module support + | +- Set version information on all module symbols + | +- Kernel module loader + +- ... + +Every entry has its own dependencies. These dependencies are used +to determine the visible of an entry. Any child entry is only +visible if its parent entry is also visible. + +Menu entries +------------ + +A single configuration option is defined like this: + +config MODVERSIONS + bool "Set version information on all module symbols" + depends MODULES + help + Usually, modules have to be recompiled whenever you switch to a new + kernel. ... + +Every line starts with a key word and can be followed by multiple arguments. +"config" starts a new config entry. The following lines define attributes +for this config option. Attributes can be the type of the config option, +input prompt, dependencies, help text and default values. A config option +can be defined multiple times, but every definition can have only a single +input prompt and the type must not conflict. + +Menu dependencies +----------------- + +Dependencies define the visibility of a menu entry. When a dependency +exprecession evaluates not to 'n', the entry is visible. Additionally +the dependency limits the input range of tristate choice symbols. + +Menu structure +-------------- + +The position of a menu entry in the tree is determined in two ways. First +it can be specified explicitely: + +menu "Network device support" + depends NET + +config NETDEVICES + ... + +endmenu + +All entries within the "menu" ... "endmenu" block become a submenu of +"Processor type and features". All subentries have the same dependencies +than the menu entry, e.g. this means the dependency "NET" is added to the +dependencies of the option NETDEVICES. +The other way to generate the menu structure is done by analyzing the +dependencies. If a menu entry somehow depends on the previous entry, it +can be made a submenu of it. + +config MODULES + bool "Enable loadable module support" + +config MODVERSIONS + bool "Set version information on all module symbols" + depends MODULES + +comment "module support disabled" + depends !MODULES + +MODVERSIONS directly depends on MODULES, this means it's only visible if +MODULES is different from 'n'. The comment on the other hand is always +visible when MODULES it's visible (the dependency of MODULES are part +of the comment dependencies). + +Menu attributes +--------------- + +A menu attribute can have a number of attributes. Not all of them are +applicable everywhere (see spec). +Input prompt: Every menu entry can have at most one menu entry, which +is used to display to the user. An input prompt is either defined with +"prompt" or it can be defined with the type. +Type definition: Every config option must have a type, known types are +currently: bool, tristate, string, hex, integer. +Default value: It's possible to assign a config option a default value. +This default is always used, when the option wasn't explicitly set by +the user. This means it's either used as default value for input prompts +or the value is saved to the kernel configuration. Multiple default +values can be specified and every one has it's own dependencies. If +multiple default values are visible, the first defined one is active. +A default is not limited to a single menu entry, this means the default +doesn't has to be defined with a input prompt, but it can also be +overridden by prepend it with another definition. +Dependencies: Dependencies can be either defined with "depends", then +there are applied to all attributes of a menu entry, or attribute +specific dependencies can be defined with "if", which immediately +follows the attribute. + + |