Output files modules.order -------------------------------------------------- This file records the order in which modules appear in Makefiles. This is used by modprobe to deterministically resolve aliases that match multiple modules. modules.builtin -------------------------------------------------- This file lists all modules that are built into the kernel. This is used by modprobe to not fail when trying to load something builtin. Environment variables KCPPFLAGS -------------------------------------------------- Additional options to pass when preprocessing. The preprocessing options will be used in all cases where kbuild does preprocessing including building C files and assembler files. KAFLAGS -------------------------------------------------- Additional options to the assembler (for built-in and modules). AFLAGS_MODULE -------------------------------------------------- Additional module specific options to use for $(AS). AFLAGS_KERNEL -------------------------------------------------- Additional options for $(AS) when used for assembler code for code that is compiled as built-in. KCFLAGS -------------------------------------------------- Additional options to the C compiler (for built-in and modules). CFLAGS_KERNEL -------------------------------------------------- Additional options for $(CC) when used to compile code that is compiled as built-in. CFLAGS_MODULE -------------------------------------------------- Additional module specific options to use for $(CC). LDFLAGS_MODULE -------------------------------------------------- Additional options used for $(LD) when linking modules. KBUILD_VERBOSE -------------------------------------------------- Set the kbuild verbosity. Can be assigned 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) Environment variable KBUILD_EXTMOD 3) Environment 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 specified using "O=...". Setting "O=..." takes precedence over KBUILD_OUTPUT. KBUILD_DEBARCH -------------------------------------------------- For the deb-pkg target, allows overriding the normal heuristics deployed by deb-pkg. Normally deb-pkg attempts to guess the right architecture based on the UTS_MACHINE variable, and on some architectures also the kernel config. The value of KBUILD_DEBARCH is assumed (not checked) to be a valid Debian architecture. 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 such as x86 and sparc have aliases. x86: i386 for 32 bit, x86_64 for 64 bit sh: sh for 32 bit, sh64 for 64 bit sparc: sparc32 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 in 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. INSTALLKERNEL -------------------------------------------------- Install script called when using "make install". The default name is "installkernel". The script will be called with the following arguments: $1 - kernel version $2 - kernel image file $3 - kernel map file $4 - default install path (use root directory if blank) The implementation of "make install" is architecture specific and it may differ from the above. INSTALLKERNEL is provided to enable the possibility to specify a custom installer when cross compiling a kernel. 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 value will be used as the options to the strip command. INSTALL_FW_PATH -------------------------------------------------- INSTALL_FW_PATH specifies 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 specifies 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_SIGN_PIN -------------------------------------------------- This variable allows a passphrase or PIN to be passed to the sign-file utility when signing kernel modules, if the private key requires such. KBUILD_MODPOST_WARN -------------------------------------------------- KBUILD_MODPOST_WARN can be set to avoid errors in case of undefined symbols in the final module linking stage. It changes such errors into warnings. KBUILD_MODPOST_NOFINAL -------------------------------------------------- KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. This is solely useful to speed up test compiles. KBUILD_EXTRA_SYMBOLS -------------------------------------------------- For modules that use symbols from other modules. See more details in modules.txt. ALLSOURCE_ARCHS -------------------------------------------------- For tags/TAGS/cscope targets, you can specify more than one arch to be included in the databases, separated by blank space. E.g.: $ make ALLSOURCE_ARCHS="x86 mips arm" tags To get all available archs you can also specify all. E.g.: $ make ALLSOURCE_ARCHS=all tags 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. KBUILD_LDS -------------------------------------------------- The linker script with full path. Assigned by the top-level Makefile. KBUILD_VMLINUX_INIT -------------------------------------------------- All object files for the init (first) part of vmlinux. Files specified with KBUILD_VMLINUX_INIT are linked first. KBUILD_VMLINUX_MAIN -------------------------------------------------- All object files for the main part of vmlinux. KBUILD_VMLINUX_LIBS -------------------------------------------------- All .a "lib" files for vmlinux. KBUILD_VMLINUX_INIT, KBUILD_VMLINUX_MAIN, and KBUILD_VMLINUX_LIBS together specify all the object files used to link vmlinux.