From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755797AbYESEnT (ORCPT ); Mon, 19 May 2008 00:43:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751301AbYESEnM (ORCPT ); Mon, 19 May 2008 00:43:12 -0400 Received: from mta23.gyao.ne.jp ([125.63.38.249]:42480 "EHLO mx.gate01.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750785AbYESEnM (ORCPT ); Mon, 19 May 2008 00:43:12 -0400 Date: Mon, 19 May 2008 13:41:41 +0900 From: Paul Mundt To: David Howells Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] binfmt_elf_fdpic: Magical stack pointer index, for NEW_AUX_ENT compat. Message-ID: <20080519044141.GA10077@linux-sh.org> Mail-Followup-To: Paul Mundt , David Howells , Andrew Morton , linux-kernel@vger.kernel.org References: <20080516090150.GA16496@linux-sh.org> <12478.1210936953@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12478.1210936953@redhat.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 16, 2008 at 12:22:33PM +0100, David Howells wrote: > Paul Mundt wrote: > > > While implementing binfmt_elf_fdpic on SH it quickly became apparent > > that SH was the first platform to support both binfmt_elf_fdpic and > > binfmt_elf, as well as the only of the FDPIC platforms to make use of the > > auxvt. > > > > Currently binfmt_elf_fdpic uses a special version of NEW_AUX_ENT() where > > the first argument is the entry displacement after csp has been adjusted, > > being reset after each adjustment. As we have no ability to sort this out > > through the platform's ARCH_DLINFO, this index needs to be managed > > entirely in create_elf_fdpic_tables(). Presently none of the platforms > > that set their own auxvt entries are able to do so through their > > respective ARCH_DLINFOs when using binfmt_elf_fdpic. > > > > In addition to this, binfmt_elf_fdpic has been looking at > > DLINFO_ARCH_ITEMS for the number of architecture-specific entries in the > > auxvt. This is legacy cruft, and is not defined by any platforms in-tree, > > even those that make heavy use of the auxvt. AT_VECTOR_SIZE_ARCH is > > always available, and contains the number that is of interest here, so we > > switch to using that unconditionally as well. > > > > As this has direct bearing on how much stack is used, platforms that have > > configurable (or dynamically adjustable) NEW_AUX_ENT calls need to either > > make AT_VECTOR_SIZE_ARCH more fine-grained, or leave it as a worst-case > > and live with some lost stack space if those entries aren't pushed (some > > platforms may also need to purposely sacrifice some space here for > > alignment considerations, as noted in the code -- although not an issue > > for any FDPIC-capable platform today). > > > > Signed-off-by: Paul Mundt > > Acked-by: David Howells As the SH FDPIC stuff depends on this, I'll fold this in to my 2.6.27 tree with the above Acked-by, which will trickle in to -mm and linux-next directly.