Re: Kernel progress

[David Brownlee <abs%netbsd.org@localhost>]

On 14 February 2015 at 20:01, Jean-Baptiste Boric <jblbeurope%gmail.com@localhost> wrote:
> Yet more updates :
>
> I got NetBSD booting up to being prompted for a root device (log from the
> serial port) :

Pretty cool :)

> [...]
> Jump to kernel!
> kernel_text=0x80100000 edata=0x802ebe10 end=0x802fb0f0
> phys segment: 0x1eff000 @ 0x100000
> adding 0x1d03000 @ 0x2fc000 to freelist 0
> pmap_steal_memory: seg 0: 0x2fc 0x2fc 0x1ffe 0x1ffe
> pmap_steal_memory: seg 0: 0x31b 0x31b 0x1ffe 0x1ffe
> pmap_steal_memory: seg 0: 0x31d 0x31d 0x1ffe 0x1ffe
> Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
>     2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015
>     The NetBSD Foundation, Inc.  All rights reserved.
> Copyright (c) 1982, 1986, 1989, 1991, 1993
>     The Regents of the University of California.  All rights reserved.
>
> NetBSD 7.99.4 (RAMDISK) #50: Thu Feb 12 19:26:12 CET 2015
>
> boricj%vm-netbsd.mail.net@localhost:/home/boricj/obj.playstation2/sys/arch/playstation2/compile/RAMDISK
> total memory = 32768 KB
> avail memory = 28956 KB
> mainbus0 (root)cpu0 at mainbus0 addr 0xffffffff: Toshiba R5900 CPU (0x2e20)
> Rev. 2.0 with software emulated floating point
> cpu0: 48 TLB entries, 16MB max page size
> cpu0: 16KB/64B 2-way set-associative L1 instruction cache
> cpu0: 8KB/64B 2-way set-associative write-back L1 data cache
> rn_init: radix functions require max_keylen be set
> root on md0a dumps on md0b
> Supported file systems: procfs null msdos mfs ffs cd9660
> no file system for md0 (dev 0x600)
> cannot mount root, error = 79
> root device (default md0a):
>
> More importantly, I found out that GXemul can emulate the PlayStation 2.
> Although it doesn't emulate much beyond the Emotion Engine, COP0, a
> framebuffer and a bunch of timers/interrupts, it can handle the NetBSD
> kernel. I added basic serial port support to GXemul to see the logs, and I
> could use DDB from within the emulator (no working interrupts means a panic
> is needed to drop into DDB). It reached the root device prompt too.
>
> Now the bad news : it seems that GXemul is a dead project, so I have nowhere
> to put the patch beyond GitHub (https://github.com/boricj/gxemul, branch
> playstation2).

If the original gxemul author is non responsive after sending patches
back you could always provide a patchset which could be used by the
emulators/gxemul pkgsrc package, so the out of the box gxemul on
NetBSD and related systems is ps2 serial capable :)

> Also, I don't think I'm going to be able to make much more
> progress on my own, as I basically still don't know what I'm doing (newbie
> and kernel porting is a poor match). I don't think I'm going to make
> interrupts work without studying the kernel (and the hardware) in-depth
> first.

Is the interrupt hardware similar to any of the other MIPS based
NetBSD or gxemul targets?