arjun024 / mkeykernel

A kernel that can read from keyboard and print on-screen

mkeykernel

This is a kernel that can read the characters a-z and 0-9 from the keyboard and print them on screen.

See the repo mkernel which is a minimal kernel that prints a string on the screen. mkeykernel just extends this to include keyboard support.

Blog post

Kernel 201 - Let’s write a Kernel with keyboard and screen support

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

If you get the following error message:

kc.o: In function `idt_init':
kernel.c:(.text+0x129): undefined reference to `__stack_chk_fail'

compile with the -fno-stack-protector option:

gcc -fno-stack-protector -m32 -c kernel.c -o bin/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 of mkernel repo.

Reboot.

Voila!

mkeykernel's Issues

qemu: fatal: Trying to execute code outside RAM or ROM at 0x0e0a0000

qemu: fatal: Trying to execute code outside RAM or ROM at 0x0e0a0000

EAX=00006f04 EBX=00009500 ECX=000b80a0 EDX=00006f04
ESI=00000000 EDI=00102000 EBP=00000000 ESP=00006f24
EIP=0e0a0000 EFL=00000202 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT= 000cca10 00000027
IDT= 001004e0 00000800
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000
DR6=ffff0ff0 DR7=00000400
CCS=00000020 CCD=00000010 CCO=SARL
EFER=0000000000000000
FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000
XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000
XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000
XMM06=00000000000000000000000000000000 XMM07=00000000000000000000000000000000
./debug_debian.sh: line 5: 3842 Aborted qemu-system-i386 -kernel kernel-101

yup

error ld

ld: warning: cannot find entry symbol entry; defaulting to 0000000000100000
ld: kc.o:kernel.c:(.text+0x8f): undefined reference to keyboard_handler' ld: kc.o:kernel.c:(.text+0xcf): undefined reference to write_port'
ld: kc.o:kernel.c:(.text+0xe3): undefined reference to write_port' ld: kc.o:kernel.c:(.text+0xf7): undefined reference to write_port'
ld: kc.o:kernel.c:(.text+0x10b): undefined reference to write_port' ld: kc.o:kernel.c:(.text+0x11f): undefined reference to write_port'
ld: kc.o:kernel.c:(.text+0x133): more undefined references to write_port' follow ld: kc.o:kernel.c:(.text+0x1ac): undefined reference to load_idt'
ld: kc.o:kernel.c:(.text+0x1c9): undefined reference to write_port' ld: kc.o:kernel.c:(.text+0x1e7): undefined reference to write_port'
ld: kc.o:kernel.c:(.text+0x1f3): undefined reference to read_port' ld: kc.o:kernel.c:(.text+0x20d): undefined reference to read_port'

Can't work on bochs, always reboot when i click.