This is Chickadee, a teaching operating system built for Harvard’s CS 161.
You will need a crosscompiler and an installation of QEMU for Chickadee to run on Mac OS X. Follow these instructions:
- Install Homebrew
- Install Homebrew’s new GCC package:
brew install gcc@8 - Install Homebrew’s QEMU:
brew install qemu - Tap Sergio Benitez’s collection of cross-compilers: brew tap SergioBenitez/osxct
- Install the
x86_64-unknown-linux-gnucross-compiler toolchain: `brew install x86_64-unknown-linux-gnu`` - Edit the file
config.mkin your Chickadee directory to contain this:
CCPREFIX=x86_64-unknown-linux-gnu-
HOSTCC=gcc-8
HOSTCXX=g++-8
make run or make run-PROGRAM
Run make run-sh to start a Shell, which supports commands (e.g., echo and cat),
redirections (i.e., > and >&), pipe (i.e., |), background (i.e., &) and much more.
Play around :)
Run make NCPU=N run to run with N virtual CPUs (default is 2).
Run make SAN=1 run to run with sanitizers.
Normally Chickadee’s debug log is written to log.txt. Run make LOG=stdio run to redirect the debug log to the standard output, or make LOG=file:FILENAME run to redirect it to FILENAME.
Run make D=1 run to ask QEMU to print verbose information about interrupts
and CPU resets to the standard error. This setting will also cause QEMU to
quit after encountering a triple fault (normally it will reboot).
make run-PROGRAM runs p-PROGRAM.cc as the first non-init process. The
default is alloc.
make HALT=1 run-PROGRAM should make QEMU exit once all processes are done.
If you experience runtime errors involving obj/libqemu-nograb.so.1, put
QEMU_PRELOAD_LIBRARY= in config.mk. This disables a shim we use that
prevents QEMU from grabbing the mouse.
| File | Description |
|---|---|
types.h |
Type definitions |
lib.hh/cc |
Chickadee C library |
x86-64.h |
x86-64 hardware definitions |
elf.h |
ELF64 structures |
| File | Description |
|---|---|
bootentry.S |
Boot loader entry point |
boot.cc |
Boot loader main code |
boot.ld |
Boot loader linker script |
| File | Description |
|---|---|
kernel.hh |
Kernel declarations |
k-exception.S |
Kernel entry points |
k-init.cc |
Kernel initialization |
k-lock.hh |
Kernel spinlock |
k-vmiter.hh/cc |
Page table iterators |
k-cpu.cc |
Kernel cpustate type |
k-proc.cc |
Kernel proc type |
kernel.cc |
Kernel exception handlers |
k-memviewer.cc |
Kernel memory viewer |
kernel.ld |
Kernel linker script |
| File | Description |
|---|---|
k-memrange.hh |
Memory range type tracker |
k-hardware.cc |
General hardware access |
k-devices.hh/cc |
Keyboard, console, memory files |
k-apic.hh/cc |
Interrupt controller hardware |
k-pci.hh |
PCI bus hardware |
k-mpspec.cc |
Boot-time configuration |
k-sanitizers.cc |
Sanitizer support |
| File | Description |
|---|---|
u-lib.cc/hh |
Process library and system call implementations |
p-allocator.cc |
Allocator process |
process.ld |
Process binary linker script |
| File | Description |
|---|---|
chickadeefs.hh |
Defines chkfs (ChickadeeFS) layout |
journalreplayer.cc |
Logic for replaying chkfs journals |
The main output of the build process is a disk image,
chickadeeos.img. QEMU “boots” off this disk image, but the image
could conceivably boot on real hardware! The build process also
produces other files that can be useful to examine.
| File | Description |
|---|---|
obj/kernel.asm |
Kernel assembly (with addresses) |
obj/kernel.sym |
Kernel defined symbols |
obj/p-allocator.asm, sym |
Same for process binaries |