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A minimalist kernel

Home Page: https://arjunsreedharan.org/post/82710718100/kernels-101-lets-write-a-kernel

License: GNU General Public License v2.0

C 60.33% Assembly 39.67%

mkernel's Introduction

mkernel

This is a minimalist kernel which prints "my first kernel" on the screen and then hangs.

The kernel is multi-boot compliant and loads with GRUB.

Blog post

Kernel 101 – Let’s write a Kernel

Build commands

nasm -f elf32 kernel.asm -o kasm.o

gcc -m32 -c kernel.c -o kc.o

ld -m elf_i386 -T link.ld -o kernel kasm.o kc.o

Test on emulator

qemu-system-i386 -kernel kernel

Get to boot

GRUB requires your kernel executable to be of the pattern kernel-<version>.

So, rename the kernel:

mv kernel kernel-701

Copy it to your boot partition (assuming you are superuser):

cp kernel-701 /boot/kernel-701

Configure your grub/grub2 similar to what is given in _grub_grub2_config folder.

Reboot.

Voila!

The next step

See mkeykernel repo

mkernel's People

Contributors

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mohamed lcmust balazsbela psachin docooler ecerulm maitreyak bmanojkumar iwpiv michals atticus88 loveragred njohncash samkerliham cronjoe alfonsokim nickaby siomkim cartertsai cameronp98 natashalouien markmelham shirgho mattervin keikoabe colourful987 killinux insionng liusongwei jethrochen calvinlee wsygb yitusandan nishiwode322 idontknowwhatiam airbaycreative brandon515 justbabychub gongchengra maxwellyu1024 satejk mrtrix niuruyutian marsmallowed zglx2008 mannmann2 yiivon thezawad ywang2014 richardkiene qwjzh lesterbogran atmo losintikfos hotelzululima prog012 udaykadaboina supermanever virajshah chaoticadev chenbk85 m0n0ph1 kuldeepiitg gabouh hytd chandrakanthmg dentmaged glumpo kyler-m rbrovko putizl radu-matei steven0129 bryant1410 iwritethings rako9000 geek14 nonsensecreativity j4cobgarby helderfigueiredo slaffcheff sidoshiro jasoncox576 rwscarb nullcore1024 cnchenpu huddy1985 1ay1 programming086 johnlunney zhzenghui neo4reo sursir vandeurenglenn tadryanom wei-n-ning fromasmtodisasm sharpist stuartwesterman debugpro

mkernel's Issues

Adding grub entry in 0.97

How should I add entry to grub 0.97
I have created VM and installed Ubuntu 12.04
I have also compiled kernel file and moved in to /boot directory
I edited file /etc/default/grub by adding an entry

title myKernel
    root (hd0,0)
    kernel /boot/kernel-701 ro

After this I try to update grub #sudo update-grub
But I got error saying title command not found.
What am I missing here?

Is there any way to compile them into ISO file?

so that we can run it on VMware etc.

You should be using a cross-compiler

The tutorial seems to be assuming the use of a hosted compiler, but if anyone wants to do serious development you should be using a cross-compiler or you will run into problems.

No mitigation against Meltdown attack

mkernel doesn't unmap vulnerable memory pages from userspace, which makes it vulnerable to the Meltdown attack on Intel CPUs. I advise against using it for critical cloud services as long as this issue remains.

Invalid magic number

Hi,
I am using Ubuntu 14.04.
I followed the steps on your blog, added an entry to grub.cfg like this

menuentry 'My Kernel' { 
   set root='hd0,msdos1'
   #my kernel executable is kernel-101, I even tried simply /kernel-101 btw
   multiboot /boot/kernel-101 ro
}

And I updated my grub with
sudo update-grub

And when I restart, it throws me
error: invalid magic number

What could be the problem?