Subject: Re: Linux on a RiscPC 600

From: David Seery <[email-masked]>
Date: Wed, 17 May 2000 17:12:39 +0100

On 16 May, Philip Blundell <[email-masked]> wrote:

> Ah, I see.  Well, you can download a tarball of the source that lkab is
> using from its ftp directory and give that a go.

I can't seem to get this at the moment, inkvine is refusing me
permission to access that directory.

> Check that you turned on floating point emulation when you built the
> kernel.

Ah, another quality mistake there.  I think I did have that wrong first
time round.  I still can't get it to work though.  Now it crashes
round about trying to calculate the module dependencies (the first process
it starts, I take it), with something like

Calculating module dependencies...
Unable to handle kernel paging request at virtual address 000e3390
memmap=1C3CC000, pgd=c0bcc000
*pgd=1c3d2011, *pmd=1c3d2011, *pte=00000000, *ppte=00000000
Internal error: Oops 2
CPU: 0
pc:  [<c0043d4c>]  lr: [<c0040148>]
sp:  c01afecc  ip: c01afeec  fp: c01afee8
r10: 400fed50  r9: 00000000  r8: 0000000a
r7:  c000a140  r6: c01c8a2c  r5: 000e338c  r4: 000e338c
r3:  4001dab8  r2: 400fed50  r1: c01c8a3c  r0: c000a140
Flags nzCv  IRQs on  FIQs on  Mode SVC_32  Segment user
Process init (pid 1, stackpage=c01af000)

I'm quite sure that getting this thing to build properly is not as
difficult as I'm making out, so I'm rapidly coming to the conclusion
that I'm missing something pretty elementary.  I've tried various
combinations of processor type and putting bits and pieces into the
kernel and taking them out again, and none of it seems to make a scrap
of difference, so I've attached my current .config file to this
mail.  If anyone can spot anything very wrong with it I'll be
grateful.  At the moment it's nothing much more than the basic
rpc_config defaults.

I can't now remember the ins and outs of each processor type,
and all my documentation is at home so I can't get at it,
but I tried building with the 26-bit APCS instead.  It failed
to build (looks like my arch-rpc/hardware.h file wasn't meant to
coexist with entry-armo.S?), but would it be worth trying to get
this to work?

David

-- 
David Seery                       Room H6
[email-masked]                   Christ's College

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---

From: Russell King - ARM Linux Admin <[email-masked]>
Date: Thu, 18 May 2000 00:55:20 +0100 (BST)

> coexist with entry-armo.S?), but would it be worth trying to get

No.  Definitely not.  The processor vectors in page 0 for interrupts
and exceptions are all entered in 32-bit mode, and some processors
do not support the 26-bit model here (StrongARM, ARM7xx I believe).
ARM6xx does however.

There is a fundamental problem though with 26-bit and that is the
mere fact that it is 26-bit, and not 32-bit.  Not enough space in
memory for everything to be reasonably positioned without imposing
stupidly small limits.
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