# Linux Kernel Module Cheat
The perfect emulation setup to study and develop the <<linux-kernel>> v5.9.2, kernel modules, <<qemu-buildroot-setup,QEMU>>, <<gem5-buildroot-setup,gem5>> and x86_64, ARMv7 and ARMv8 <<userland-assembly,userland>> and <<baremetal-setup,baremetal>> assembly, <<c,ANSI C>>, <<cpp,C++>> and <<posix,POSIX>>. <<gdb>> and <<kgdb>> just work. Powered by <<about-the-qemu-buildroot-setup,Buildroot>> and <<about-the-baremetal-setup,crosstool-NG>>. Highly automated. Thoroughly documented. Automated <<test-this-repo,tests>>.

### 28.5. Userland assembly C standard library

All examples except the Freestanding programs link to the C standard library.

This allows using the C standard library for IO, which is very convenient and portable across host OSes.

It also exposes other non-IO functionality that is very convenient such as `memcmp`.

The C standard library infrastructure is implemented in the common userland / baremetal source files:

- lkmc.c

- lkmc.h

- lkmc/aarch64.h

- lkmc/arm.h

- lkmc/x86_64.h

- Freestanding programs