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Diffstat (limited to 'Documentation/kbuild/kbuild.txt')
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diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt new file mode 100644 index 00000000000..51771847e81 --- /dev/null +++ b/Documentation/kbuild/kbuild.txt @@ -0,0 +1,126 @@ +Environment variables + +KCPPFLAGS +-------------------------------------------------- +Additional options to pass when preprocessing. The preprocessing options +will be used in all cases where kbuild do preprocessing including +building C files and assembler files. + +KAFLAGS +-------------------------------------------------- +Additional options to the assembler. + +KCFLAGS +-------------------------------------------------- +Additional options to the C compiler. + +KBUILD_VERBOSE +-------------------------------------------------- +Set the kbuild verbosity. Can be assinged same values as "V=...". +See make help for the full list. +Setting "V=..." takes precedence over KBUILD_VERBOSE. + +KBUILD_EXTMOD +-------------------------------------------------- +Set the directory to look for the kernel source when building external +modules. +The directory can be specified in several ways: +1) Use "M=..." on the command line +2) Environmnet variable KBUILD_EXTMOD +3) Environmnet variable SUBDIRS +The possibilities are listed in the order they take precedence. +Using "M=..." will always override the others. + +KBUILD_OUTPUT +-------------------------------------------------- +Specify the output directory when building the kernel. +The output directory can also be specificed using "O=...". +Setting "O=..." takes precedence over KBUILD_OUTPUT + +ARCH +-------------------------------------------------- +Set ARCH to the architecture to be built. +In most cases the name of the architecture is the same as the +directory name found in the arch/ directory. +But some architectures suach as x86 and sparc has aliases. +x86: i386 for 32 bit, x86_64 for 64 bit +sparc: sparc for 32 bit, sparc64 for 64 bit + +CROSS_COMPILE +-------------------------------------------------- +Specify an optional fixed part of the binutils filename. +CROSS_COMPILE can be a part of the filename or the full path. + +CROSS_COMPILE is also used for ccache is some setups. + +CF +-------------------------------------------------- +Additional options for sparse. +CF is often used on the command-line like this: + + make CF=-Wbitwise C=2 + +INSTALL_PATH +-------------------------------------------------- +INSTALL_PATH specifies where to place the updated kernel and system map +images. Default is /boot, but you can set it to other values + + +MODLIB +-------------------------------------------------- +Specify where to install modules. +The default value is: + + $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE) + +The value can be overridden in which case the default value is ignored. + +INSTALL_MOD_PATH +-------------------------------------------------- +INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory +relocations required by build roots. This is not defined in the +makefile but the argument can be passed to make if needed. + +INSTALL_MOD_STRIP +-------------------------------------------------- +INSTALL_MOD_STRIP, if defined, will cause modules to be +stripped after they are installed. If INSTALL_MOD_STRIP is '1', then +the default option --strip-debug will be used. Otherwise, +INSTALL_MOD_STRIP will used as the options to the strip command. + +INSTALL_FW_PATH +-------------------------------------------------- +INSTALL_FW_PATH specify where to install the firmware blobs. +The default value is: + + $(INSTALL_MOD_PATH)/lib/firmware + +The value can be overridden in which case the default value is ignored. + +INSTALL_HDR_PATH +-------------------------------------------------- +INSTALL_HDR_PATH specify where to install user space headers when +executing "make headers_*". +The default value is: + + $(objtree)/usr + +$(objtree) is the directory where output files are saved. +The output directory is often set using "O=..." on the commandline. + +The value can be overridden in which case the default value is ignored. + +KBUILD_MODPOST_WARN +-------------------------------------------------- +KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined +symbols in the final module linking stage. + +KBUILD_MODPOST_FINAL +-------------------------------------------------- +KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. +This is solely usefull to speed up test compiles. + +KBUILD_EXTRA_SYMBOLS +-------------------------------------------------- +For modules use symbols from another modules. +See more details in modules.txt. |