summaryrefslogtreecommitdiffstats
path: root/Documentation/kbuild/kconfig.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/kbuild/kconfig.rst')
-rw-r--r--Documentation/kbuild/kconfig.rst300
1 files changed, 300 insertions, 0 deletions
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.