From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ftp.linux-mips.org ([194.74.144.162]:50380 "EHLO ftp.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757876AbXJLRwO (ORCPT ); Fri, 12 Oct 2007 13:52:14 -0400 Date: Fri, 12 Oct 2007 18:52:10 +0100 From: Ralf Baechle Subject: Re: [PATCH] Discardable strings for init and exit sections Message-ID: <20071012175209.GA1110@linux-mips.org> References: <20071012171938.GB6476@stusta.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071012171938.GB6476@stusta.de> Sender: linux-arch-owner@vger.kernel.org To: Adrian Bunk Cc: "Maciej W. Rozycki" , Franck Bui-Huu , linux-arch@vger.kernel.org, linux-mips@linux-mips.org, Andrew Morton , linux-kernel@vger.kernel.org List-ID: On Fri, Oct 12, 2007 at 07:19:38PM +0200, Adrian Bunk wrote: > I have an objection against this approach: > > Our __*init*/__*exit* annotations are already a constant source of bugs, > and adding more pifalls (e.g. forgotten removal of _i()/_e() when a > function is no longer __*init*/__*exit*) doesn't sound like a good plan. > > Shouldn't it be possible to automatically determine where to put the > strings? I don't know enough gcc/ld voodoo for being able to tell > whether it is currently possible, and if yes how, but doing it > automatically sounds like the only solution that wouldn't result in an > unmaintainable mess. gcc tends to place data such as strings or jump tables generated from switches not into a place were it would be easily discardable. The latter is the reason that on MIPS we can't discard __exit functions at all - a switch table in .rodata might be referencing discarded code in .exit.text which makes ld fail. When I discussed this with some gcc people a while ago nobody really had a good suggestion to solve this. Ralf