From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andi Kleen <ak@suse.de>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: 32-bit syscalls from 64-bit process on x86-64?
Date: Fri, 03 Dec 2004 15:16:29 -0800 [thread overview]
Message-ID: <1102115789.8707.122.camel@localhost> (raw)
In-Reply-To: <20041203061520.GG31767@wotan.suse.de>
On Fri, 2004-12-03 at 07:15 +0100, Andi Kleen wrote:
> int 0x80 from 64bit will call 32bit syscalls.
Hm, that's not what I found. If I run int 0x80 with [re]ax=1, I get
exit with a 32-bit process and write with a 64-bit one.
> But some things
> will not work properly, e.g. signals because they test the 32bit
> flag in the task_struct. So you would still get 64bit signal frames.
OK, I can deal with that, since signals are never directly delivered to
the client.
> There are some other such tests, but they probably wont affect you.
>
> There were some plans at one point to allow to toggle the flag
> using personality or prctl, but so far it hasn't been implemented.
> There is also no way to do 64bit calls from a 32bit executable.
What about my idea of using distinct ranges of syscall numbers to
disambiguate them?
J
next prev parent reply other threads:[~2004-12-03 23:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-02 16:22 32-bit syscalls from 64-bit process on x86-64? Jeremy Fitzhardinge
2004-12-02 18:52 ` Jeremy Fitzhardinge
2004-12-03 6:15 ` Andi Kleen
2004-12-03 23:16 ` Jeremy Fitzhardinge [this message]
2004-12-04 14:40 ` Petr Vandrovec
2004-12-04 21:33 ` Jeremy Fitzhardinge
2004-12-08 2:30 ` Jeremy Fitzhardinge
2004-12-14 7:45 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2004-12-14 22:01 Petr Vandrovec
2004-12-15 4:27 ` Andi Kleen
2004-12-15 10:50 ` Jeremy Fitzhardinge
2004-12-15 10:55 ` Andi Kleen
2004-12-15 20:58 ` Jeremy Fitzhardinge
2004-12-16 4:35 ` Andi Kleen
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