diff options
Diffstat (limited to 'Documentation/kbuild')
| -rw-r--r-- | Documentation/kbuild/kbuild.txt | 13 | ||||
| -rw-r--r-- | Documentation/kbuild/kconfig-language.txt | 32 | ||||
| -rw-r--r-- | Documentation/kbuild/kconfig.txt | 5 | ||||
| -rw-r--r-- | Documentation/kbuild/makefiles.txt | 53 |
4 files changed, 97 insertions, 6 deletions
diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt index 7c2a89ba674c..68e32bb6bd80 100644 --- a/Documentation/kbuild/kbuild.txt +++ b/Documentation/kbuild/kbuild.txt @@ -201,3 +201,16 @@ KBUILD_ENABLE_EXTRA_GCC_CHECKS -------------------------------------------------- If enabled over the make command line with "W=1", it turns on additional gcc -W... options for more extensive build-time checking. + +KBUILD_BUILD_TIMESTAMP +-------------------------------------------------- +Setting this to a date string overrides the timestamp used in the +UTS_VERSION definition (uname -v in the running kernel). The value has to +be a string that can be passed to date -d. The default value +is the output of the date command at one point during build. + +KBUILD_BUILD_USER, KBUILD_BUILD_HOST +-------------------------------------------------- +These two variables allow to override the user@host string displayed during +boot and in /proc/version. The default value is the output of the commands +whoami and host, respectively. diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt index b507d61fd41c..44e2649fbb29 100644 --- a/Documentation/kbuild/kconfig-language.txt +++ b/Documentation/kbuild/kconfig-language.txt @@ -113,6 +113,13 @@ applicable everywhere (see syntax). That will limit the usefulness but on the other hand avoid the illegal configurations all over. +- limiting menu display: "visible if" <expr> + This attribute is only applicable to menu blocks, if the condition is + false, the menu block is not displayed to the user (the symbols + contained there can still be selected by other symbols, though). It is + similar to a conditional "prompt" attribude for individual menu + entries. Default value of "visible" is true. + - numerical ranges: "range" <symbol> <symbol> ["if" <expr>] This allows to limit the range of possible input values for int and hex symbols. The user can only input a value which is larger than @@ -303,7 +310,8 @@ menu: "endmenu" This defines a menu block, see "Menu structure" above for more -information. The only possible options are dependencies. +information. The only possible options are dependencies and "visible" +attributes. if: @@ -381,3 +389,25 @@ config FOO limits FOO to module (=m) or disabled (=n). +Kconfig symbol existence +~~~~~~~~~~~~~~~~~~~~~~~~ +The following two methods produce the same kconfig symbol dependencies +but differ greatly in kconfig symbol existence (production) in the +generated config file. + +case 1: + +config FOO + tristate "about foo" + depends on BAR + +vs. case 2: + +if BAR +config FOO + tristate "about foo" +endif + +In case 1, the symbol FOO will always exist in the config file (given +no other dependencies). In case 2, the symbol FOO will only exist in +the config file if BAR is enabled. diff --git a/Documentation/kbuild/kconfig.txt b/Documentation/kbuild/kconfig.txt index cca46b1a0f6c..c313d71324b4 100644 --- a/Documentation/kbuild/kconfig.txt +++ b/Documentation/kbuild/kconfig.txt @@ -48,11 +48,6 @@ KCONFIG_OVERWRITECONFIG If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not break symlinks when .config is a symlink to somewhere else. -KCONFIG_NOTIMESTAMP --------------------------------------------------- -If this environment variable exists and is non-null, the timestamp line -in generated .config files is omitted. - ______________________________________________________________________ Environment variables for '{allyes/allmod/allno/rand}config' diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 5d145bb443c0..47435e56c5da 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -40,11 +40,13 @@ This document describes the Linux kernel Makefiles. --- 6.6 Commands useful for building a boot image --- 6.7 Custom kbuild commands --- 6.8 Preprocessing linker scripts + --- 6.9 Generic header files === 7 Kbuild syntax for exported headers --- 7.1 header-y --- 7.2 objhdr-y --- 7.3 destination-y + --- 7.4 generic-y === 8 Kbuild Variables === 9 Makefile language @@ -499,6 +501,18 @@ more details, with real examples. gcc >= 3.00. For gcc < 3.00, -malign-functions=4 is used. Note: cc-option-align uses KBUILD_CFLAGS for $(CC) options + cc-disable-warning + cc-disable-warning checks if gcc supports a given warning and returns + the commandline switch to disable it. This special function is needed, + because gcc 4.4 and later accept any unknown -Wno-* option and only + warn about it if there is another warning in the source file. + + Example: + KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) + + In the above example, -Wno-unused-but-set-variable will be added to + KBUILD_CFLAGS only if gcc really accepts it. + cc-version cc-version returns a numerical version of the $(CC) compiler version. The format is <major><minor> where both are two digits. So for example @@ -955,6 +969,11 @@ When kbuild executes, the following steps are followed (roughly): used when linking modules. This is often a linker script. From commandline LDFLAGS_MODULE shall be used (see kbuild.txt). + KBUILD_ARFLAGS Options for $(AR) when creating archives + + $(KBUILD_ARFLAGS) set by the top level Makefile to "D" (deterministic + mode) if this option is supported by $(AR). + --- 6.2 Add prerequisites to archprepare: The archprepare: rule is used to list prerequisites that need to be @@ -1209,6 +1228,14 @@ When kbuild executes, the following steps are followed (roughly): The kbuild infrastructure for *lds file are used in several architecture-specific files. +--- 6.9 Generic header files + + The directory include/asm-generic contains the header files + that may be shared between individual architectures. + The recommended approach how to use a generic header file is + to list the file in the Kbuild file. + See "7.4 generic-y" for further info on syntax etc. + === 7 Kbuild syntax for exported headers The kernel include a set of headers that is exported to userspace. @@ -1265,6 +1292,32 @@ See subsequent chapter for the syntax of the Kbuild file. In the example above all exported headers in the Kbuild file will be located in the directory "include/linux" when exported. + --- 7.4 generic-y + + If an architecture uses a verbatim copy of a header from + include/asm-generic then this is listed in the file + arch/$(ARCH)/include/asm/Kbuild like this: + + Example: + #arch/x86/include/asm/Kbuild + generic-y += termios.h + generic-y += rtc.h + + During the prepare phase of the build a wrapper include + file is generated in the directory: + + arch/$(ARCH)/include/generated/asm + + When a header is exported where the architecture uses + the generic header a similar wrapper is generated as part + of the set of exported headers in the directory: + + usr/include/asm + + The generated wrapper will in both cases look like the following: + + Example: termios.h + #include <asm-generic/termios.h> === 8 Kbuild Variables |