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Re: 32-bit ABI

To: linux-mips@linux-mips.org
Subject: Re: 32-bit ABI
From: Thiemo Seufer <ica2_ts@csv.ica.uni-stuttgart.de>
Date: Sat, 24 Apr 2004 09:09:07 +0200
In-reply-to: <Pine.GSO.4.10.10404240825540.10762-100000@helios.et.put.poznan.pl>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <Pine.LNX.4.55.0404231849480.14494@jurand.ds.pg.gda.pl> <Pine.GSO.4.10.10404240825540.10762-100000@helios.et.put.poznan.pl>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.5.5.1i
Stanislaw Skowronek wrote:
> Hello,
> 
> why do we attempt to compile the kernel with 32-bit GAS abi and 64-bit GCC
> abi?

It optimizes away a few hundred kB of kernel code, but requires in turn
a sign-extended load-address plus ugly objcopy hacks.

> Is it because the module loader is broken and supports only 32-bit
> ELFs? Then what about machines which load their kernels at weird 64-bit
> addresses, like 0xa800000020004000 (Octane)?

Ah, the same as for IP28. :-) They can't be supported by the current
scheme.

> I have changed it to 64-bit abi in my Octane kernel, because it won't even
> compile otherwise. I've got gcc 3.3.2, gas 2.14.

You'll have to extend all the hand-coded asm memory accesses to do
64bit adressing as well.


Thiemo

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