8b41fc4454
Commit bc081dd6e9 ("kbuild: generate modules.builtin") added
infrastructure to generate modules.builtin, the list of all
builtin modules.
Basically, it works like this:
- Kconfig generates include/config/tristate.conf, the list of
tristate CONFIG options with a value in a capital letter.
- scripts/Makefile.modbuiltin makes Kbuild descend into
directories to collect the information of builtin modules.
I am not a big fan of it because Kbuild ends up with traversing
the source tree twice.
I am not sure how perfectly it should work, but this approach cannot
avoid false positives; even if the relevant CONFIG option is tristate,
some Makefiles forces obj-m to obj-y.
Some examples are:
arch/powerpc/platforms/powermac/Makefile:
obj-$(CONFIG_NVRAM:m=y) += nvram.o
net/ipv6/Makefile:
obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
net/netlabel/Makefile:
obj-$(subst m,y,$(CONFIG_IPV6)) += netlabel_calipso.o
Nobody has complained about (or noticed) it, so it is probably fine to
have false positives in modules.builtin.
This commit simplifies the implementation. Let's exploit the fact
that every module has MODULE_LICENSE(). (modpost shows a warning if
MODULE_LICENSE is missing. If so, 0-day bot would already have blocked
such a module.)
I added MODULE_FILE to <linux/module.h>. When the code is being compiled
as builtin, it will be filled with the file path of the module, and
collected into modules.builtin.info. Then, scripts/link-vmlinux.sh
extracts the list of builtin modules out of it.
This new approach fixes the false-positives above, but adds another
type of false-positives; non-modular code may have MODULE_LICENSE()
by mistake. This is not a big deal, it is just the code is always
orphan. We can clean it up if we like. You can see cleanup examples by:
$ git log --grep='make.* explicitly non-modular'
To sum up, this commits deletes lots of code, but still produces almost
equivalent results. Please note it does not increase the vmlinux size at
all. As you can see in include/asm-generic/vmlinux.lds.h, the .modinfo
section is discarded in the link stage.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
300 lines
9.1 KiB
ReStructuredText
300 lines
9.1 KiB
ReStructuredText
===================
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Kconfig make config
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===================
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This file contains some assistance for using `make *config`.
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Use "make help" to list all of the possible configuration targets.
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The xconfig ('qconf'), menuconfig ('mconf'), and nconfig ('nconf')
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programs also have embedded help text. Be sure to check that for
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navigation, search, and other general help text.
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General
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-------
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New kernel releases often introduce new config symbols. Often more
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important, new kernel releases may rename config symbols. When
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this happens, using a previously working .config file and running
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"make oldconfig" won't necessarily produce a working new kernel
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for you, so you may find that you need to see what NEW kernel
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symbols have been introduced.
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To see a list of new config symbols, use::
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cp user/some/old.config .config
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make listnewconfig
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and the config program will list any new symbols, one per line.
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Alternatively, you can use the brute force method::
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make oldconfig
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scripts/diffconfig .config.old .config | less
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----------------------------------------------------------------------
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Environment variables for `*config`
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KCONFIG_CONFIG
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--------------
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This environment variable can be used to specify a default kernel config
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file name to override the default name of ".config".
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KCONFIG_OVERWRITECONFIG
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-----------------------
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If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
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break symlinks when .config is a symlink to somewhere else.
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`CONFIG_`
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---------
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If you set `CONFIG_` in the environment, Kconfig will prefix all symbols
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with its value when saving the configuration, instead of using the default,
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`CONFIG_`.
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----------------------------------------------------------------------
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Environment variables for '{allyes/allmod/allno/rand}config'
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KCONFIG_ALLCONFIG
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-----------------
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(partially based on lkml email from/by Rob Landley, re: miniconfig)
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--------------------------------------------------
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The allyesconfig/allmodconfig/allnoconfig/randconfig variants can also
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use the environment variable KCONFIG_ALLCONFIG as a flag or a filename
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that contains config symbols that the user requires to be set to a
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specific value. If KCONFIG_ALLCONFIG is used without a filename where
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KCONFIG_ALLCONFIG == "" or KCONFIG_ALLCONFIG == "1", `make *config`
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checks for a file named "all{yes/mod/no/def/random}.config"
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(corresponding to the `*config` command that was used) for symbol values
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that are to be forced. If this file is not found, it checks for a
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file named "all.config" to contain forced values.
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This enables you to create "miniature" config (miniconfig) or custom
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config files containing just the config symbols that you are interested
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in. Then the kernel config system generates the full .config file,
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including symbols of your miniconfig file.
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This 'KCONFIG_ALLCONFIG' file is a config file which contains
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(usually a subset of all) preset config symbols. These variable
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settings are still subject to normal dependency checks.
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Examples::
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KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
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or::
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KCONFIG_ALLCONFIG=mini.config make allnoconfig
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or::
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make KCONFIG_ALLCONFIG=mini.config allnoconfig
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These examples will disable most options (allnoconfig) but enable or
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disable the options that are explicitly listed in the specified
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mini-config files.
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----------------------------------------------------------------------
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Environment variables for 'randconfig'
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KCONFIG_SEED
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------------
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You can set this to the integer value used to seed the RNG, if you want
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to somehow debug the behaviour of the kconfig parser/frontends.
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If not set, the current time will be used.
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KCONFIG_PROBABILITY
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-------------------
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This variable can be used to skew the probabilities. This variable can
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be unset or empty, or set to three different formats:
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======================= ================== =====================
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KCONFIG_PROBABILITY y:n split y:m:n split
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======================= ================== =====================
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unset or empty 50 : 50 33 : 33 : 34
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N N : 100-N N/2 : N/2 : 100-N
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[1] N:M N+M : 100-(N+M) N : M : 100-(N+M)
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[2] N:M:L N : 100-N M : L : 100-(M+L)
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======================= ================== =====================
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where N, M and L are integers (in base 10) in the range [0,100], and so
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that:
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[1] N+M is in the range [0,100]
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[2] M+L is in the range [0,100]
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Examples::
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KCONFIG_PROBABILITY=10
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10% of booleans will be set to 'y', 90% to 'n'
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5% of tristates will be set to 'y', 5% to 'm', 90% to 'n'
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KCONFIG_PROBABILITY=15:25
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40% of booleans will be set to 'y', 60% to 'n'
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15% of tristates will be set to 'y', 25% to 'm', 60% to 'n'
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KCONFIG_PROBABILITY=10:15:15
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10% of booleans will be set to 'y', 90% to 'n'
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15% of tristates will be set to 'y', 15% to 'm', 70% to 'n'
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----------------------------------------------------------------------
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Environment variables for 'syncconfig'
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KCONFIG_NOSILENTUPDATE
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----------------------
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If this variable has a non-blank value, it prevents silent kernel
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config updates (requires explicit updates).
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KCONFIG_AUTOCONFIG
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------------------
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This environment variable can be set to specify the path & name of the
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"auto.conf" file. Its default value is "include/config/auto.conf".
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KCONFIG_AUTOHEADER
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------------------
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This environment variable can be set to specify the path & name of the
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"autoconf.h" (header) file.
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Its default value is "include/generated/autoconf.h".
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----------------------------------------------------------------------
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menuconfig
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----------
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SEARCHING for CONFIG symbols
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Searching in menuconfig:
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The Search function searches for kernel configuration symbol
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names, so you have to know something close to what you are
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looking for.
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Example::
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/hotplug
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This lists all config symbols that contain "hotplug",
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e.g., HOTPLUG_CPU, MEMORY_HOTPLUG.
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For search help, enter / followed by TAB-TAB (to highlight
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<Help>) and Enter. This will tell you that you can also use
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regular expressions (regexes) in the search string, so if you
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are not interested in MEMORY_HOTPLUG, you could try::
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/^hotplug
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When searching, symbols are sorted thus:
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- first, exact matches, sorted alphabetically (an exact match
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is when the search matches the complete symbol name);
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- then, other matches, sorted alphabetically.
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For example: ^ATH.K matches:
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ATH5K ATH9K ATH5K_AHB ATH5K_DEBUG [...] ATH6KL ATH6KL_DEBUG
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[...] ATH9K_AHB ATH9K_BTCOEX_SUPPORT ATH9K_COMMON [...]
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of which only ATH5K and ATH9K match exactly and so are sorted
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first (and in alphabetical order), then come all other symbols,
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sorted in alphabetical order.
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----------------------------------------------------------------------
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User interface options for 'menuconfig'
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MENUCONFIG_COLOR
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----------------
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It is possible to select different color themes using the variable
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MENUCONFIG_COLOR. To select a theme use::
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make MENUCONFIG_COLOR=<theme> menuconfig
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Available themes are::
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- mono => selects colors suitable for monochrome displays
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- blackbg => selects a color scheme with black background
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- classic => theme with blue background. The classic look
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- bluetitle => a LCD friendly version of classic. (default)
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MENUCONFIG_MODE
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---------------
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This mode shows all sub-menus in one large tree.
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Example::
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make MENUCONFIG_MODE=single_menu menuconfig
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----------------------------------------------------------------------
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nconfig
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-------
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nconfig is an alternate text-based configurator. It lists function
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keys across the bottom of the terminal (window) that execute commands.
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You can also just use the corresponding numeric key to execute the
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commands unless you are in a data entry window. E.g., instead of F6
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for Save, you can just press 6.
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Use F1 for Global help or F3 for the Short help menu.
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Searching in nconfig:
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You can search either in the menu entry "prompt" strings
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or in the configuration symbols.
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Use / to begin a search through the menu entries. This does
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not support regular expressions. Use <Down> or <Up> for
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Next hit and Previous hit, respectively. Use <Esc> to
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terminate the search mode.
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F8 (SymSearch) searches the configuration symbols for the
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given string or regular expression (regex).
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NCONFIG_MODE
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------------
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This mode shows all sub-menus in one large tree.
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Example::
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make NCONFIG_MODE=single_menu nconfig
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----------------------------------------------------------------------
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xconfig
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-------
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Searching in xconfig:
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The Search function searches for kernel configuration symbol
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names, so you have to know something close to what you are
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looking for.
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Example::
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Ctrl-F hotplug
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or::
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Menu: File, Search, hotplug
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lists all config symbol entries that contain "hotplug" in
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the symbol name. In this Search dialog, you may change the
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config setting for any of the entries that are not grayed out.
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You can also enter a different search string without having
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to return to the main menu.
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----------------------------------------------------------------------
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gconfig
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-------
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Searching in gconfig:
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There is no search command in gconfig. However, gconfig does
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have several different viewing choices, modes, and options.
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