| 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 |
| 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 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. |
