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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] qemu qemu-doc.texi
Date: Mon, 12 Jun 2006 17:47:12 +0100
References: <OF33112006.EFBB8BEE-ONC125718B.0055D73A-C125718B.00597A92@codingtechnologies.com>
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To: qemu-devel@nongnu.org
Cc: Wolfgang Schildbach <Wolfgang.Schildbach@codingtechnologies.com>

> Where would I (start to) look for the reasons behind this? Is this
> something that needs to be "fixed" on the ARM side (i.e. fix the location
> where the ARM code looks for the environment)?

Look at the code in load_elf_binary that uses target_mmap to map the loadable 
segments into memory. The page size I'm referring to below is the target page 
size (4k for qemu-arm). target_mmap is more-or-less a wrapper around normal 
mmap that deals with the corner cases and differences in page size when 
host != target. 

There are two issues:
- mmap requires the file offset be a multiple of the page size.  This is 
relatively easy to fix. If the file data is misaligned create an anonymous 
mapping and pread the data.

- The code assumes the VMA of the segments after roundind to a page boundary 
do not overlap. ie. a single memory page will contain data from no more than 
one segment. Fixing this is more complicated and probably involves merging 
the regions used by sections with "overlapping" pages.

Paul