On Fri Jan 10 2003 at 21:35:53 +0200, Ilpo Ruotsalainen wrote:
> On Fri Jan 10 2003 at 20:18:22 +0200, Ilpo Ruotsalainen wrote:
> > > Just tried booting my '060 A1200 with patched -current, gray screen
> > > nothing else... (I know the -current is otherwise good, so it must be
> > > this patch.)
> > 
> > I know this much now: It certainly finishes start_c(). It either doesn't
> > ever enter start_c_finish() or CUSTOMADDR (or the mappings) are hosed.
> 
> After some debugging I've managed to narrow it down to this:
> 
> LMMUenable_start:
> 
> /* enable the MMU */
> #if defined(M68040) || defined(M68060)
>         RELOC(mmutype, %a0)
>         cmpl    #MMU_68040,%a0@
>         jne     Lenable030
>         movl    #0xdff180,%a0
>         movw    #0xa00,%a0@
>         pflusha
>         movl    #0xdff180,%a0
>         movw    #0x00a,%a0@
>         movl    #0xc000,%d0
>         .word   0x4e7b, 0x0003          | movec %d0,%tc
>         jmp     Lunshadow:l
> #endif /* M68040 || M68060 */
> /* ENABLE, SRP_ENABLE, 8K pages, 8bit A-level, 11bit B-level */
> Ltc:    .long   0x82d08b00
> Lenable030:
>         movl    #0xdff180,%a0
>         movw    #0x0a0,%a0@
>         lea     Ltc,%a0
>         pmove   %a0@,%tc
>         jmp     Lunshadow:l
> 
> LMMUenable_end:
> 
> With the code looking like this, I end up with RED screen. Which seems
> to say it dies on the "pflusha" instruction (unless that instruction
> changes MMU mappings or such? I'd think it's the movec that changes them
> but I don't know really almost anything about 68k MMUs...).

Hmpf, sent this a few minutes too early. Next iteration with the
"pflusha" instruction removed produced a kernel that booted
successfully. So that seems to be the guilty one, I'm not m68k guru
enough to instantly know why it would die on that...

-- 
Ilpo Ruotsalainen - <lonewolf@iki.fi> - http://www.iki.fi/lonewolf/