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Date: Fri, 04 Jan 2008 13:25:58 -0800
From: Maxim Sobolev <sobomax@FreeBSD.org>
Organization: Sippy Software, Inc.
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To: Tim Kientzle <kientzle@FreeBSD.org>
References: <477C82F0.5060809@freebsd.org>	<863ateemw2.fsf@ds4.des.no>	<200801032200.25650.peter.schuller@infidyne.com>	<alpine.BSF.1.00.0801031305340.39341@goat.gigo.com>	<8663yac62d.fsf@ds4.des.no>
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Cc: =?ISO-8859-1?Q?Dag-Erling_Sm=F8rgrav?= <des@des.no>,
	freebsd-current@FreeBSD.org, Peter Schuller <peter.schuller@infidyne.com>,
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Subject: ELF dynamic loader name [was: sbrk(2) broken]
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Tim Kientzle wrote:
>> "Sidegrading" is supposed to work now in HEAD; with a little hacking,
>> you can build an amd64 world and kernel on the i386 world, install the
>> kernel, reboot, and install world.  AFAIK, the required hacking involves
>> copying /libexec/ld-elf.so.1 to /libexec/ld-elf32.so.1 ...
> 
> I wonder when we'll have to standardize /libexec/<arch>/ to support
> multiple architectures for things like ld-elf.so.1.  It used to only
> be a concern for those rare people running diskless over multiple
> architectures, but the case of i386 binaries on amd64 is a little
> more common.
> 
> On the other hand, if ld-elf.so.1 is fairly unique in this
> concern, it might be simpler to rename it to:
>    ld-elf-{i386,amd64,ppc,...}.so.1

Good point, it's silly that i386 binary running on amd64 kernel requires 
ld-elf32.so.1, while ld-elf.so.1 when running on i386 kernel. It adds 
unneeded complexity for running i386 jail or chroot on amd64 for example.

I wonder if we can do what Tim said - rename dynamic loader to actually 
include architecture name. I am pretty sure it would allow to remove 
quite few special cases from the kernel elf/emulation code and possibly 
from the cross build logic.

-Maxim