What is kbuild file?

The kbuild Makefile specifies object files for vmlinux in the $(obj-y) lists. These lists depend on the kernel configuration. Kbuild compiles all the $(obj-y) files. It then calls “$(AR) rcSTP” to merge these files into one built-in.a file. This is a thin archive without a symbol table.

What does obj m mean?

1. From the Linux kernel documentation for obj-m: “$(obj-m) specifies object files that are built as kernel modules.”. There isn’t an obj-m+ . The + is part of the += operator to append to a variable. It can also be used to append subdirectories which will be entered recursively.

What is Kbuild?

kbuild is an assortment of scripts that are built-in inside the kernel’s sources, and the kernel build process does not depend on anything named kmk. The kernel build system depends only on the standard GNU make, and it takes care of compiling its own helper programs, most of which are located under scripts/ directory.

What is built-in O?

built-in.o files are the compiled product of each directory target of the kernel that is not built as a module. See Documentation/kbuild/makefiles.txt. Each subdirectory has a kbuild Makefile which carries out the commands passed down from above.

What is kernel build?

The kernel build system allows you to specify a different architecture from the current system with the ARCH= argument. The build system also allows you to specify the specific compiler that you wish to use for the build by using the CC= argument or a cross-compile toolchain with the CROSS_COMPILE argument.

What are KConfig files?

What is KConfig? KConfig is a selection-based configuration system originally developed for the Linux kernel. It is commonly used to select build-time options and to enable or disable features, and has now found use in other projects beyond the Linux kernel.

What is Symvers?

symvers is a plain text file which is generated after kernel building. It records CRC values of all the exported symbols in both vmlinux and modules.

What is a Makefile target?

A simple makefile consists of “rules” with the following shape: target … : prerequisites … recipe … … A target is usually the name of a file that is generated by a program; examples of targets are executable or object files. A target can also be the name of an action to carry out, such as ‘ clean ‘ (see Phony Targets).

What is Kconfiglib?

Kconfiglib is a Python 2/3 library for scripting and extracting information from Kconfig configuration systems. It can do the following, among other things: Programmatically get and set symbol values.

What is Defconfig?

defconfig. Generates a new kernel configuration with the default answer being used for all options. The default values are taken from a file located in the arch/$ARCH/defconfig file, where $ARCH refers to the specific architecture for which the kernel is being built.

What is Vmlinux bin?

vmlinux is a statically linked executable file that contains the Linux kernel in one of the object file formats supported by Linux, which includes Executable and Linkable Format (ELF), Common Object File Format (COFF) and a. out.