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From: Mathieu Ropert <mro@adviseo.fr>
To: xen-devel@lists.xensource.com
Subject: Guest image and symtable alignement
Date: Tue, 11 Apr 2006 15:14:51 +0200	[thread overview]
Message-ID: <443BABCB.6000900@adviseo.fr> (raw)

Hi,

I found a difference between Xen's domain kernel symbol table alignement 
and alignement found in some other OS, like BSD.

On Xen (looking at loadelfsymtab() in common/elf.c), symtable length is 
stored on an ELFROUND rounded address (4 bytes on 32bits, 8 bytes on 64 
bits) followed by the ELF header. As length is an int, header isn't 8 
bytes aligned on 64 bits (no problem on 32 bit as sizeof (int) == 
ELFROUND), whereas OS like BSD expects the header to be aligned on a 
long boundary.

I'd like to know whichever is right (if there is any standard about 
that), because this may cause some incompatibilty problems with future 
ports attempts.
Was also wondering if we could just fix it be moving all this 4 bytes 
forward in the guest OS code (may break pointer references, if any?).

Thanks,
Mathieu

             reply	other threads:[~2006-04-11 13:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-04-11 13:14 Mathieu Ropert [this message]
2006-04-13  9:18 ` Guest image and symtable alignement Keir Fraser

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