tinylaker / EwokOS

A microkernel os

EwokOS

.Author

Misa.Z [e-mail]

.About

A microkernel os for learning operating system. 

.Environment & Tools

Linux:	
	Ubuntu Linux 16.04 with "qemu-system-arm","gcc-arm-none-eabi","gdb-arm-none-eabi"
	installed(can install by "apt")

Mac OSX(with brew installed):	
	brew tap PX4/homebrew-px4
	brew install gcc-arm-none-eabi-49
	brew install qemu
	(set the right PATH environment after installed)

.make and run

make rootfs first, and then make kernel.

"make run": run EwokOS; 
  "qemu-system-arm -kernel build/EwokOS.bin -initrd ../rootfs/build/initfs"
  boot kernel file and load init ramdisk.

"make debug": run EwokOS at debug server-mode;
"make gdb": debug EwokOS (debug client-mode);

.commands

Most of commands are in 'rootfs/sbin' directory, like:
ls, ps, pwd, test ......

.Source code read-guide

kernel/arm/boot.S
kernel/src/mm/kalloc.c
kernel/src/mm/mmu.c
kernel/src/proc.c 
kernel/src/sheduler.c
kernel/src/syscalls.c
kernel/src/kipc.c
kernel/src/vfs.c
kernel/src/mm/shm.c

rootfs/lib/src/stdlib.c
rootfs/lib/src/unistd.c
rootfs/lib/src/pmessage.c
rootfs/lib/src/shm.c

rootfs/sbin/init/init.c
rootfs/kdev/initfs/initfs.c
rootfs/sbin/shell/shell.c

Tips: Don't fall in love with assembly too much;).

. Kernel init memory map

PhyMem                         VMem
0x00000000-0x00080000  map to  0x80000000-0x80080000  (8M)

PhyMem        VMem         Desc
----------------------------------------------------
0x00000000    0xFFFF0000   interrupt table
0x00010000    0x80010000   Kernel start (load to)
***           ***          (_initStack, _irqStack, _startupPageDir)
***           ***          Kernel end, Kernel PageDir Table start
+16KB         +16KB        Kernel PageDir Table end.
+32KB         +32KB        kernel malloc base
+2M           +2M          kernel malloc end (size=2M).
......
0x08000000    0x08000000   init ramdisk base (load initrd to)
0x08010000    0x08010000   init ramdisk end (size=1M).
......
physical ram top           Share memory start base               
......
MMIO_BASE_PHY MMIO_BASE    MMIO base (arch)
......