From: Ralf Baechle <ralf@linux-mips.org>
To: Ronny Meeus <ronny.meeus@gmail.com>
Cc: linux-mips@linux-mips.org
Subject: Re: 2GB userspace limitation in ABI N32
Date: Wed, 10 Oct 2012 10:07:56 +0200 [thread overview]
Message-ID: <20121010080756.GC6740@linux-mips.org> (raw)
In-Reply-To: <CAMJ=MEfFsJH6Cqkow7-w3a352iYiWWi+ubOSJaqhh2bp2MqPZg@mail.gmail.com>
On Wed, Oct 10, 2012 at 08:32:47AM +0200, Ronny Meeus wrote:
> I have a legacy application that we want to port to a MIPS (Cavium)
> architecture from a PPC based one.
> The board has 4GB memory of which we actually need almost 3GB in
> application space. On the PPC this is no issue since the split
> user/kernel is 3GB/1GB.
> We have to use the N32 ABI Initial tests on MIPS showed me the
> user-space limit of 2GB.
> We do not want to port the application to a 64bit
>
> Now the question is: are there any workarounds, tricks existing to get
> around this limitation?
> I found some mailthreads on this subject (n32-big ABI -
> http://gcc.gnu.org/ml/gcc/2011-02/msg00278.html,
> http://elinux.org/images/1/1f/New-tricks-mips-linux.pdf) but is looks
> like this is not accepted by the community. Is there any process
> planned or made in this area?
I think limited time and gain killed the propoosed ABI rather than
theoretical issues raised. Other architectures such as i386 - well,
IIRC any 32-bit ABI with more than 2GB userspace and a signed
ptrdiff_t - are suffering from them as well.
Also there's limited gain and even more limited time to implement things ...
Ralf
next prev parent reply other threads:[~2012-10-10 8:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-10 6:32 2GB userspace limitation in ABI N32 Ronny Meeus
2012-10-10 8:07 ` Ralf Baechle [this message]
2012-10-10 12:57 ` Rich Felker
2012-10-10 16:56 ` David Daney
2012-10-10 17:10 ` Maciej W. Rozycki
2012-10-10 17:34 ` David Daney
2012-10-10 17:49 ` Ronny Meeus
2012-10-10 18:08 ` David Daney
2012-10-10 15:12 ` Ronny Meeus
2012-10-12 10:18 ` Ralf Baechle
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