|'''''||
    .|'   ...'||
   ||   .|...|||  ..  .... 
 .|'    ||    || .' .|...|| 
||......|'|...||'|. || 
             .||. ||.'|...'

Zero Kernel is a tiny kernel implementation that was originally targeted for ARM Corex-M microcontrollers. The reason to start this project was that most of currently (or back then) available RTOSes for M0 were bit bloat and secondly I found architectures based on ARMv6-M to be quite challenging and interesting platforms for RTOS/kernel development, especially when ARMv6-M is compared to ARMv7-M used in M4 core or any Cortex-A cores using real ARM architectures.

One of the original goals of Zero Kernel was to make it CMSIS-RTOS compliant where possible, as some concepts of Zeke were not actually CMSIS compliant from the begining. However the scope of the project shifted pretty early and the kernel is no longer CMSIS compatible at any level. Currently Zeke is no moving towards POSIX-like system and its user space is taking a very Unix-like shape. Nowadays Zeke is a bit bloatty when compared to the original standard of a bloated OS but I claim Zeke is still quite tightly integrated system, compared to any other Unix-like OS implementation.

• Kernel
  • Fully pre-emptible kernel mode
  • Object-oriented thread scheduling system
  • One-to-one kernel threads for user processes
  • freeBSD-like sysctl interface
• Processes
  • ASLR
  • Copy-On-Write virtual memory
  • Per process capabilities
  • Unix-like fork and exec
  • elf32 support
• IPC
  • Signals
  • mmap
  • pipes
  • pty
• File Systems
  • Complete file system abstraction (VFS)
  • FAT12/16/32 support
  • Fast RAM file system
  • MBR support
  • freeBSD-like device file interface
• Userland
  • Mostly C99 compliant libc
  • Standard user application separation by using POSIX processes
  • System call based kernel services

Scheduler system redesigned to provide easier API to implement new scheduling policies as well as to make future migration to MP easier.

+-----------+-----------------------+
| HAL       | Status                |
+-----------+-----------------------+
| ARM11     | OK                    |
+-----------+-----------------------+
|   BCM2835 | OK                    |
+-----------+-----------------------+
| MIPSel32  | -                     |
+-----------+-----------------------+
|   JZ4780  | -                     |
+-----------+-----------------------+

To successfully compile Zeke, you'll need the following packages/tools:

• make >3.8
• llvm 3.3 or 3.4
• clang 3.3 or 3.4
• binutils -- arm-none-eabi -- mipsel-sde-elf
• bash
• mkdosfs and mtools for creating a rootfs image
• cloc for source code stats
• ncurses-devel

doc-book target:

• LaTeX + various packages
• latexmk
• gnuplot

Doxygen targets:

• Doxygen
• man for viewing man pages

• configure- Set defaults for files in config dir
• make all rootfs - Compile the kernel, user space and create a rootfs image
• make kernel.img - Compile the kernel
• make world - Compile only the user space without creating a rootfs image
• make opttest - Compile on target tests
• make clean - Clean all compilation targets

Run make help for full list of targets and compilation flags.

Qemu from rpi branch of git@github.com:Torlus/qemu.git repository seems to work best for BCM2835/Raspberry Pi version of Zeke.

../src/configure --prefix=[PATH TO BIN] --target-list=arm-softmmu,arm-linux-user,armeb-linux-user --enable-sdl
make -j4 && sudo make install

Zeke should boot just fine with, practically, any bootloader that is capable of loading a linux image. However Zeke only supports ATAGs for gathering device information so some older bootloader may work better. Though ATAGs are optional so basically any bootloader should work if you compile Zeke without configATAG.