From: Richard Henderson <rth@redhat.com>
To: Mark Kettenis <mark.kettenis@xs4all.nl>
Cc: echristo@redhat.com, binutils@sourceware.org
Subject: Re: [RFA] Update OpenBSD/mips64 support
Date: Thu, 14 Apr 2005 01:24:00 -0000 [thread overview]
Message-ID: <20050414012436.GA1150@redhat.com> (raw)
In-Reply-To: <200504132248.j3DMmU9A016212@elgar.sibelius.xs4all.nl>
On Thu, Apr 14, 2005 at 12:48:30AM +0200, Mark Kettenis wrote:
> n32 is 32-bit pointers and 64-bit registers. 64-bit registers are
> required. It's also a heck of a lot faster than n64 :)
>
> And a bit of a security nightmare if you have a 64-bit kernel...
I wouldn't say that. Think of it as merely a 64-bit application that
Just So Happens to only use the low 31 bits.
The only thing the kernel needs to do is for mmap (0, ...) choose an
address in the low 32 bits. For everything else, the application will
provide a correct value or its broken and will suffer the consequences.
Unlike o32, you don't have to sign or zero-extend syscall arguments at
kernel entry points, because the application will have already done
that because of how n32 passes 32-bit arguments.
But it's not like I'm going to work on it, so feel free to ignore me.
r~
next prev parent reply other threads:[~2005-04-14 1:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-13 22:14 Mark Kettenis
2005-04-13 22:30 ` Eric Christopher
2005-04-13 22:37 ` Mark Kettenis
2005-04-13 22:39 ` Eric Christopher
2005-04-13 22:48 ` Mark Kettenis
2005-04-13 22:51 ` Eric Christopher
2005-04-14 10:42 ` Maciej W. Rozycki
2005-04-14 1:24 ` Richard Henderson [this message]
2005-04-14 10:44 ` Maciej W. Rozycki
2005-04-13 22:35 ` Thiemo Seufer
2005-04-13 22:45 ` Mark Kettenis
2005-04-13 23:34 ` Thiemo Seufer
2005-04-14 17:04 ` Mark Kettenis
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