From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752595AbZHXOHy (ORCPT ); Mon, 24 Aug 2009 10:07:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752484AbZHXOHw (ORCPT ); Mon, 24 Aug 2009 10:07:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2806 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752468AbZHXOHv (ORCPT ); Mon, 24 Aug 2009 10:07:51 -0400 Date: Mon, 24 Aug 2009 10:06:29 -0400 From: Jason Baron To: Paul Mundt , Frederic Weisbecker , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, rostedt@goodmis.org, peterz@infradead.org, mathieu.desnoyers@polymtl.ca, jiayingz@google.com, mbligh@google.com, lizf@cn.fujitsu.com Subject: Re: [PATCH 05/12] update FTRACE_SYSCALL_MAX Message-ID: <20090824140629.GA2656@redhat.com> References: <7fca984182691041c0d139eccd080f82045f86f7.1249932670.git.jbaron@redhat.com> <20090811110023.GC4938@nowhere> <20090824134151.GB18974@linux-sh.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090824134151.GB18974@linux-sh.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 24, 2009 at 10:41:52PM +0900, Paul Mundt wrote: > > On Mon, Aug 10, 2009 at 04:52:35PM -0400, Jason Baron wrote: > > > update FTRACE_SYSCALL_MAX to the current number of syscalls > > > > > > Signed-off-by: Jason Baron > > > > > > --- > > > arch/x86/include/asm/ftrace.h | 4 ++-- > > > 1 files changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h > > > index bd2c651..7113654 100644 > > > --- a/arch/x86/include/asm/ftrace.h > > > +++ b/arch/x86/include/asm/ftrace.h > > > @@ -30,9 +30,9 @@ > > > > > > /* FIXME: I don't want to stay hardcoded */ > > > #ifdef CONFIG_X86_64 > > > -# define FTRACE_SYSCALL_MAX 296 > > > +# define FTRACE_SYSCALL_MAX 299 > > > #else > > > -# define FTRACE_SYSCALL_MAX 333 > > > +# define FTRACE_SYSCALL_MAX 337 > > > #endif > > > > > > I don't remember why we had to use a hardcoded number. > > Is there no way to keep being sync with the current number of > > syscalls? We dwant to avoid patching the kernel each time we > > have a new syscall :-) > > > I hope you can clarify what the meaning of this is supposed to be > exactly. Is this number supposed to be the last usable syscall, or is it > supposed to be the equivalent of NR_syscalls? > I am using as the equivalent of NR_syscalls. > Presently on SH we have this as NR_syscalls - 1, while on s390 I see it > is treated as NR_syscalls directly. s390 opencodes the NR_syscalls > directly and so presently blows up in -next due to a missing > FTRACE_SYSCALL_MAX definition: > > http://kisskb.ellerman.id.au/kisskb/buildresult/1120523/ > > I was in the process of fixing that up when I noticed this difference. > x86 seems to also treat this as NR_syscalls - 1, but that looks to me > like there is an off-by-1 in arch_init_ftrace_syscalls() causing the last > syscall to be skipped? I don't see how its used as 'NR_syscalls - 1' on x86, arch_init_ftrace_syscalls() does: for (i = 0; i < FTRACE_SYSCALL_MAX; i++) { meta = find_syscall_meta(psys_syscall_table[i]); syscalls_metadata[i] = meta; } So the last syscall should not be skipped. We should probably convert *all* the arches to be using NR_syscalls directly. thanks, -Jason