linux-kernel - Re: [PATCH 1/2 v2] FLAT: split the stack & data alignments

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Date:	Fri, 28 May 2010 02:05:27 -0400
From:	Mike Frysinger <vapier.adi@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	uclinux-dev@...inux.org, David Howells <dhowells@...hat.com>,
	David McCullough <davidm@...pgear.com>,
	Greg Ungerer <gerg@...inux.org>,
	Paul Mundt <lethal@...ux-sh.org>,
	uclinux-dist-devel@...ckfin.uclinux.org,
	microblaze-uclinux@...e.uq.edu.au, Michal Simek <monstr@...str.eu>,
	linux-m32r@...linux-m32r.org,
	Hirokazu Takata <takata@...ux-m32r.org>,
	Yoshinori Sato <ysato@...rs.sourceforge.jp>
Subject: Re: [PATCH 1/2 v2] FLAT: split the stack & data alignments

On Wed, May 26, 2010 at 04:45, Mike Frysinger wrote:
> The stack and data have different alignment requirements, so don't force
> them to wear the same shoe.  Increase the data alignment to match that
> which the elf2flt linker script has always been using: 0x20 bytes.  Not
> only does this bring the kernel loader in line with the toolchain, but
> it also fixes a swath of gcc tests which try to force larger alignment
> values but randomly fail when the FLAT loader fails to deliver.

btw, a follow up patch might be to move the shared lib identifiers
from the start of the data section to the end of it so that the
re-aligning isnt necessary (we'd get a 4k page alignment from mmap and
such).  but i cant seem to figure out how these identifiers are being
read/written.  otherwise, the fact that we're force aligning to 0x20
bytes means that there is always room for 8 identifiers ... no point
in flipping between 1 or 4, at least from this point of view ...
-mike
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