Re: [Qemu-devel] ARM v4t support

[Rob Landley <rob@landley.net>]

On Sunday 29 November 2009 03:57:37 Filip Navara wrote:
> On Sun, Nov 29, 2009 at 8:00 AM, Rob Landley <rob@landley.net> wrote:
> > On Friday 27 November 2009 05:35:26 Filip Navara wrote:
> >> On Fri, Nov 27, 2009 at 12:17 PM, Vincent Sanders <vince@kyllikki.org>
> >
> > wrote:
> >> > I appear to be unable to take a hint, your silence on this patch in
> >> > the past probably ought to have been a clue. however this will be the
> >> > last time I bother to try and get anything merged so you wont have to
> >> > be disturbed again.
> >> >
> >> > The attached patch adds V4t support to the ARM emulation, its pretty
> >> > much the same as the last time it was posted. It is correct in
> >> > everything it does to the best of my knowledge however you will as
> >> > usual no doubt find a corner case it does not cover and reject it.
> >>
> >> I have already sent more complete patch for ARM7TDMI emulation:
> >>
> >> http://www.mail-archive.com/qemu-devel@nongnu.org/msg17205.html
> >> http://patchwork.ozlabs.org/patch/36841/
> >
> > That's a link to an archive that gives you html but not a raw patch.
> >  (Huh, it says you sent it to the list but I'm not finding it in my mail
> > folder. Rummage, rummage, rummage...  Ah, your original patch was dated
> > December 31 1969.)
>
> Yep, a bug in TortoiseGIT that was later fixed.
>
> > Ok, dug it up, applied it, booted an -M versatilepb kernel built with an
> > armv4tl compiler that I'm assured works for real armv4tl hardware, and I
> > get no boot messages if I say "-cpu arm7tdmi", but it boots fine if I
> > don't say that.
> >
> > Let's try my armv4l setup (which I've booted on real armv4tl hardware,
> > albeit with a different kernel .config but qemu hasn't got a board
> > emulation for the Tin Can Tools Hammer, last I checked...)  That's an
> > OABI which doesn't depend on the Thumb extensions...
> >
> > Nope, that's armv4 OABI, and I've tested the output of that compiler on
> > real hardware, albeit with a different kernel .config.
> >
> > Your patch does not work for me.  Is there a kernel .config change I need
> > to do for this?  Looking in the kernel kconfig stuff, the only way to
> > select arm7tdmi is to disable MMU support.  Is this a nommu processor?
> >  (I know there are armv4t processors _with_ mmu...)
>
> It is nommu processor, so I would be surprised to see any of the
> kernels running. Unfortunately I don't have a ready-to-use kernel
> .config file for it, since I never even tried it with Linux.

Did you add any armv4t processors with mmu?  I believe the actual hardware I 
tested was an ARM920T.  Vincent's patch claims to add arm920T, I tested yours 
because you claimed it was "more complete".

I guess I should go test vincent's.

> > What kernel .config, -M, and -cpu and  did you use to test an armv4t
> > system image with your patch?
>
> -M at91pes (which is included in other patches from around the same
> time, but was never merged)

"Included in other patches"...  How _many_ other patches?  And how far is 
"around"?

If you'd like to resubmit them as a batch, I can try coming up with a kernel 
.config.  (And a uClibc .config since I haven't actually tried a nommu system 
yet.)

Thanks,

Rob
-- 
Latency is more important than throughput. It's that simple. - Linus Torvalds