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From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: Saving to 32 bits of GPRs in signal context
Date: Wed, 30 May 2007 13:59:29 +0200
To: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>,
	Steve Munroe <sjmunroe@us.ibm.com>,
	Ulrich Weigand <Ulrich.Weigand@de.ibm.com>,
	Anton Blanchard <anton@samba.org>
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> I think actually it would be useful to have the saving/restoring of
> the high 32 bits controlled by a prctl, so that programs have to ask
> explicitly for the new behaviour (and programs that don't want to use
> the high 32 bits don't incur the extra overhead).

This prctl() is needed if you want to support DSOs containing
64-bit insns.  It would be nice to have some ELF flag as well
though, so most of this can be handled automatically.


Segher