The purpose of this repo, is to show how to write and test a very simple Linux kernel module, using the V programming language .
NB: this is very experimental and may break in the future.
It works as of 2021/10/23, with gcc 10.3.0
and V 0.2.4 008d15d
.
Update: it also works as of 2022/08/16, with gcc 10.3.0
and V 0.3.0 3bc01d6
too.
The -no-builtin -no-preludes
options produce C code, that may not
even compile, if it depends on some of V's builtin
module features, like
dynamic arrays, maps, array/string methods, string interpolation etc.
A C compiler, and a V compiler.
On a Debian system, you can install them with:
apt-get install gcc
git clone https://github.com/vlang/v && cd v && make && ./v symlink
Once you have them installed, you can keep them up to date with:
apt-get upgrade
v up
make
See also https://www.kernel.org/doc/html/latest/kbuild/modules.html .
sudo insmod vhellokernel.ko
cat /proc/modules |grep vhellokernel
If everything is ok, you should see something like this:
vhellokernel 16384 0 - Live 0x0000000000000000 (OE)
Use dmesg | tail
to see the messages that the module wrote.
sudo rmmod vhellokernel.ko
0[12:47:53] /v/misc/2021_10_22__02/simple_kernel_module_in_v LINUX $ make clean test
make -C /lib/modules/`uname -r`/build M=$PWD clean
make[1]: Entering directory '/usr/src/linux-headers-5.11.0-38-generic'
CLEAN /v/misc/2021_10_22__02/simple_kernel_module_in_v/Module.symvers
make[1]: Leaving directory '/usr/src/linux-headers-5.11.0-38-generic'
rm -rf vhellokernel.o vhellokernel.c
v -no-builtin -no-preludes -o vhellokernel.c vhellokernel.v
make -C /lib/modules/`uname -r`/build M=$PWD modules
make[1]: Entering directory '/usr/src/linux-headers-5.11.0-38-generic'
CC [M] /v/misc/2021_10_22__02/simple_kernel_module_in_v/vhellokernel.o
MODPOST /v/misc/2021_10_22__02/simple_kernel_module_in_v/Module.symvers
CC [M] /v/misc/2021_10_22__02/simple_kernel_module_in_v/vhellokernel.mod.o
LD [M] /v/misc/2021_10_22__02/simple_kernel_module_in_v/vhellokernel.ko
make[1]: Leaving directory '/usr/src/linux-headers-5.11.0-38-generic'
make load
make[1]: Entering directory '/v/misc/2021_10_22__02/simple_kernel_module_in_v'
sudo insmod vhellokernel.ko
make[1]: Leaving directory '/v/misc/2021_10_22__02/simple_kernel_module_in_v'
cat /proc/modules |grep vhellokernel
vhellokernel 16384 0 - Live 0x0000000000000000 (OE)
make unload
make[1]: Entering directory '/v/misc/2021_10_22__02/simple_kernel_module_in_v'
sudo rmmod vhellokernel.ko
make[1]: Leaving directory '/v/misc/2021_10_22__02/simple_kernel_module_in_v'
0[12:47:56] /v/misc/2021_10_22__02/simple_kernel_module_in_v LINUX $