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diff --git a/Documentation/kbuild/kconfig.rst b/Documentation/kbuild/kconfig.rst new file mode 100644 index 000000000000..88129af7e539 --- /dev/null +++ b/Documentation/kbuild/kconfig.rst @@ -0,0 +1,300 @@ +=================== +Kconfig make config +=================== + +This file contains some assistance for using `make *config`. + +Use "make help" to list all of the possible configuration targets. + +The xconfig ('qconf'), menuconfig ('mconf'), and nconfig ('nconf') +programs also have embedded help text. Be sure to check that for +navigation, search, and other general help text. + +General +------- + +New kernel releases often introduce new config symbols. Often more +important, new kernel releases may rename config symbols. When +this happens, using a previously working .config file and running +"make oldconfig" won't necessarily produce a working new kernel +for you, so you may find that you need to see what NEW kernel +symbols have been introduced. + +To see a list of new config symbols, use:: + + cp user/some/old.config .config + make listnewconfig + +and the config program will list any new symbols, one per line. + +Alternatively, you can use the brute force method:: + + make oldconfig + scripts/diffconfig .config.old .config | less + +---------------------------------------------------------------------- + +Environment variables for `*config` + +KCONFIG_CONFIG +-------------- +This environment variable can be used to specify a default kernel config +file name to override the default name of ".config". + +KCONFIG_OVERWRITECONFIG +----------------------- +If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not +break symlinks when .config is a symlink to somewhere else. + +`CONFIG_` +--------- +If you set `CONFIG_` in the environment, Kconfig will prefix all symbols +with its value when saving the configuration, instead of using the default, +`CONFIG_`. + +---------------------------------------------------------------------- + +Environment variables for '{allyes/allmod/allno/rand}config' + +KCONFIG_ALLCONFIG +----------------- +(partially based on lkml email from/by Rob Landley, re: miniconfig) + +-------------------------------------------------- + +The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also +use the environment variable KCONFIG_ALLCONFIG as a flag or a filename +that contains config symbols that the user requires to be set to a +specific value. If KCONFIG_ALLCONFIG is used without a filename where +KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", `make *config` +checks for a file named "all{yes/mod/no/def/random}.config" +(corresponding to the `*config` command that was used) for symbol values +that are to be forced. If this file is not found, it checks for a +file named "all.config" to contain forced values. + +This enables you to create "miniature" config (miniconfig) or custom +config files containing just the config symbols that you are interested +in. Then the kernel config system generates the full .config file, +including symbols of your miniconfig file. + +This 'KCONFIG_ALLCONFIG' file is a config file which contains +(usually a subset of all) preset config symbols. These variable +settings are still subject to normal dependency checks. + +Examples:: + + KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig + +or:: + + KCONFIG_ALLCONFIG=mini.config make allnoconfig + +or:: + + make KCONFIG_ALLCONFIG=mini.config allnoconfig + +These examples will disable most options (allnoconfig) but enable or +disable the options that are explicitly listed in the specified +mini-config files. + +---------------------------------------------------------------------- + +Environment variables for 'randconfig' + +KCONFIG_SEED +------------ +You can set this to the integer value used to seed the RNG, if you want +to somehow debug the behaviour of the kconfig parser/frontends. +If not set, the current time will be used. + +KCONFIG_PROBABILITY +------------------- +This variable can be used to skew the probabilities. This variable can +be unset or empty, or set to three different formats: + + ======================= ================== ===================== + KCONFIG_PROBABILITY y:n split y:m:n split + ======================= ================== ===================== + unset or empty 50 : 50 33 : 33 : 34 + N N : 100-N N/2 : N/2 : 100-N + [1] N:M N+M : 100-(N+M) N : M : 100-(N+M) + [2] N:M:L N : 100-N M : L : 100-(M+L) + ======================= ================== ===================== + +where N, M and L are integers (in base 10) in the range [0,100], and so +that: + + [1] N+M is in the range [0,100] + + [2] M+L is in the range [0,100] + +Examples:: + + KCONFIG_PROBABILITY=10 + 10% of booleans will be set to 'y', 90% to 'n' + 5% of tristates will be set to 'y', 5% to 'm', 90% to 'n' + KCONFIG_PROBABILITY=15:25 + 40% of booleans will be set to 'y', 60% to 'n' + 15% of tristates will be set to 'y', 25% to 'm', 60% to 'n' + KCONFIG_PROBABILITY=10:15:15 + 10% of booleans will be set to 'y', 90% to 'n' + 15% of tristates will be set to 'y', 15% to 'm', 70% to 'n' + +---------------------------------------------------------------------- + +Environment variables for 'syncconfig' + +KCONFIG_NOSILENTUPDATE +---------------------- +If this variable has a non-blank value, it prevents silent kernel +config updates (requires explicit updates). + +KCONFIG_AUTOCONFIG +------------------ +This environment variable can be set to specify the path & name of the +"auto.conf" file. Its default value is "include/config/auto.conf". + +KCONFIG_TRISTATE +---------------- +This environment variable can be set to specify the path & name of the +"tristate.conf" file. Its default value is "include/config/tristate.conf". + +KCONFIG_AUTOHEADER +------------------ +This environment variable can be set to specify the path & name of the +"autoconf.h" (header) file. +Its default value is "include/generated/autoconf.h". + + +---------------------------------------------------------------------- + +menuconfig +---------- + +SEARCHING for CONFIG symbols + +Searching in menuconfig: + + The Search function searches for kernel configuration symbol + names, so you have to know something close to what you are + looking for. + + Example:: + + /hotplug + This lists all config symbols that contain "hotplug", + e.g., HOTPLUG_CPU, MEMORY_HOTPLUG. + + For search help, enter / followed by TAB-TAB (to highlight + <Help>) and Enter. This will tell you that you can also use + regular expressions (regexes) in the search string, so if you + are not interested in MEMORY_HOTPLUG, you could try:: + + /^hotplug + + When searching, symbols are sorted thus: + + - first, exact matches, sorted alphabetically (an exact match + is when the search matches the complete symbol name); + - then, other matches, sorted alphabetically. + + For example: ^ATH.K matches: + + ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG + [...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...] + + of which only ATH5K and ATH9K match exactly and so are sorted + first (and in alphabetical order), then come all other symbols, + sorted in alphabetical order. + +---------------------------------------------------------------------- + +User interface options for 'menuconfig' + +MENUCONFIG_COLOR +---------------- +It is possible to select different color themes using the variable +MENUCONFIG_COLOR. To select a theme use:: + + make MENUCONFIG_COLOR=<theme> menuconfig + +Available themes are:: + + - mono => selects colors suitable for monochrome displays + - blackbg => selects a color scheme with black background + - classic => theme with blue background. The classic look + - bluetitle => a LCD friendly version of classic. (default) + +MENUCONFIG_MODE +--------------- +This mode shows all sub-menus in one large tree. + +Example:: + + make MENUCONFIG_MODE=single_menu menuconfig + +---------------------------------------------------------------------- + +nconfig +------- + +nconfig is an alternate text-based configurator. It lists function +keys across the bottom of the terminal (window) that execute commands. +You can also just use the corresponding numeric key to execute the +commands unless you are in a data entry window. E.g., instead of F6 +for Save, you can just press 6. + +Use F1 for Global help or F3 for the Short help menu. + +Searching in nconfig: + + You can search either in the menu entry "prompt" strings + or in the configuration symbols. + + Use / to begin a search through the menu entries. This does + not support regular expressions. Use <Down> or <Up> for + Next hit and Previous hit, respectively. Use <Esc> to + terminate the search mode. + + F8 (SymSearch) searches the configuration symbols for the + given string or regular expression (regex). + +NCONFIG_MODE +------------ +This mode shows all sub-menus in one large tree. + +Example:: + make NCONFIG_MODE=single_menu nconfig + +---------------------------------------------------------------------- + +xconfig +------- + +Searching in xconfig: + + The Search function searches for kernel configuration symbol + names, so you have to know something close to what you are + looking for. + + Example: + Ctrl-F hotplug + or + Menu: File, Search, hotplug + + lists all config symbol entries that contain "hotplug" in + the symbol name. In this Search dialog, you may change the + config setting for any of the entries that are not grayed out. + You can also enter a different search string without having + to return to the main menu. + + +---------------------------------------------------------------------- + +gconfig +------- + +Searching in gconfig: + + There is no search command in gconfig. However, gconfig does + have several different viewing choices, modes, and options. |