Re: Kernel progress

[Jean-Baptiste Boric <jblbeurope%gmail.com@localhost>]

2015-01-10 18:01 GMT+01:00 David Brownlee <abs%netbsd.org@localhost>:
> How its going? Anything that is likely to boot on a standard playstation? :)

It already does (for some definition of booting) :-)

On the real hardware, the kernel can be booted using kernelloader3.0.
I have a standard PlayStation 2 (SCPH-30006, no Network Adapter/Hard
Drive/modchip, FreeMCBoot installed on Memory Card) with the serial
port mod (see http://www.kanshima.net/mirrors/ee-sio/ps2-ee-sio.html
and PS2DEV for details).

On PCSX2, it can be booted by directly loading the ELF file. While it
is useful for poking around with its integrated debugger, PCSX2 won't
be able to support a NetBSD (or Linux) kernel because of various
technical limitations (its objective is to run games and homebrews,
not a full-blown operating system).

For now, the kernel runs up to sysctl_init(), where it chokes on
invalid pointers. The exception handler is working (or at least it was
last time I stumbled upon an illegal instruction) and the kernel
output is sent over the Emotion Engine's serial port.

There's no drivers yet (had to comment everything due to bitrot), but
if a proper serial port driver is written, I suppose DDB/KGDB might
work over it. No drivers also means that without the serial port mod
the kernel will boot, but nothing interesting will happen.

Strangely enough, the real hardware and PCSX2 do not crash on the same spot.

I don't have much time to work on this for now (exams...), but I plan
on keep going. (How hard can resurrecting NetBSD ports be, anyway?
Turns out pretty darn hard).

Random notes : the code is on GitHub mainly for backup, but I can post
a patch here if needed. I had to modify the kernel linker script for
the gcc-mips-current external toolchain, so I broke every MIPS port.
NOGCCERROR=1 is required.

About the crash in sysctl_init() : for now I have no idea why it
crashes, and no idea why PCSX2 behaves differently from the hardware
in this case. For all I know, it can range from a stupid n00b mistake
up to a toolchain issue.