From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753575AbZHBUZd (ORCPT ); Sun, 2 Aug 2009 16:25:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753275AbZHBUZd (ORCPT ); Sun, 2 Aug 2009 16:25:33 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:55137 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752396AbZHBUZc (ORCPT ); Sun, 2 Aug 2009 16:25:32 -0400 Date: Sun, 2 Aug 2009 22:25:22 +0200 From: Ingo Molnar To: David Miller Cc: jens.axboe@oracle.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, fweisbec@gmail.com Subject: Re: [PATCH] basic perf support for sparc Message-ID: <20090802202522.GK24486@elte.hu> References: <20090729112509.GN4148@kernel.dk> <20090802.131705.81498579.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090802.131705.81498579.davem@davemloft.net> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * David Miller wrote: > From: Jens Axboe > Date: Wed, 29 Jul 2009 13:25:10 +0200 > > > -#define NR_SYSCALLS 327 > > +#define NR_SYSCALLS 328 > > When you increase this value, you have to add entries to all of > the syscall tables. The syscall dispatch checks against this as a > limit, so if you don't explicitly add an entry to all the tables, > it's possible to deref garbage past the end of the table and try > to jump to it as a syscall. > > And if you somehow arrange for adding a compat syscall entry here > for this, and build the perf tools 32-bit, you can forego all of > these rediculious issues with trying to get a 64-bit BFD library. > If the perf tools are written portably and use types like u64 etc. > for holding addresses and similar things, this should not be an > issue. > > The 32-bit sparc BFD library has full support for all the 64-bit > binary formats and whatnot. That would work too. On x86 perf works all across the compatibility spectrum, and we do use strict u32/u64 typing and ABIs. Note that we'll also solve (remove) the binutils-devel dependency, it creates a way too large set of external build constraints for perf. But in any case both 32-bit and 64-bit perf should work just fine. Ingo