Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933482Ab0GOPFX (ORCPT ); Thu, 15 Jul 2010 11:05:23 -0400 Received: from pfepb.post.tele.dk ([195.41.46.236]:34432 "EHLO pfepb.post.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933453Ab0GOPFT (ORCPT ); Thu, 15 Jul 2010 11:05:19 -0400 Date: Thu, 15 Jul 2010 17:05:14 +0200 From: Sam Ravnborg To: Steven Rostedt , Zeev Tarantov Cc: Linus Torvalds , LKML , Ingo Molnar , Frederic Weisbecker , Andrew Morton , "Rafael J. Wysocki" Subject: Re: [PATCH] tracing: properly align linker defined symbols Message-ID: <20100715150514.GB14073@merkur.ravnborg.org> References: <1278705402.1537.157.camel@gandalf.stny.rr.com> <20100709203301.GA13839@merkur.ravnborg.org> <1278721339.1537.166.camel@gandalf.stny.rr.com> <20100710063459.GA14596@merkur.ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100710063459.GA14596@merkur.ravnborg.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 Content-Length: 2754 Lines: 84 On Sat, Jul 10, 2010 at 08:34:59AM +0200, Sam Ravnborg wrote: > Zeev - please try this replacement patch. > The alignmnet is increased to 32 bytes compared to my previous version and > we introduce alignmnet for ftrace_events too. > > Sam Steven - Zeev reported that this fixed the boot problem. What is next step? Do you forward this patch or do you prefer another fix? Sam > > From 40bedb8fda25d2cf9ecdd41ab48a24104607c37e Mon Sep 17 00:00:00 2001 > From: Sam Ravnborg > Date: Sat, 10 Jul 2010 08:24:12 +0200 > Subject: [PATCH] tracing: properly align linker defined symbols > > We define a number of symbols in the linker scipt like this: > > __start_syscalls_metadata = .; > *(__syscalls_metadata) > > But we do not know the alignment of "." when we assign > the __start_syscalls_metadata symbol. > gcc started to uses bigger alignment for structs (32 bytes), > so we saw situations where the linker due to alignment > constraints increased the value of "." after the symbol assignment. > > This resulted in boot fails. > > Fix this by forcing a 32 byte alignment of "." before the > assignment. > > This patch introduces the forced alignment for > ftrace_events and syscalls_metadata. > It may be required in more places. > > Reported-by: Zeev Tarantov > Signed-off-by: Sam Ravnborg > Cc: Steven Rostedt > Cc: Frederic Weisbecker > --- > include/asm-generic/vmlinux.lds.h | 10 ++++++++++ > 1 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index 48c5299..4b5902a 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -63,6 +63,12 @@ > /* Align . to a 8 byte boundary equals to maximum function alignment. */ > #define ALIGN_FUNCTION() . = ALIGN(8) > > +/* > + * Align to a 32 byte boundary equal to the > + * alignment gcc 4.5 uses for a struct > + */ > +#define STRUCT_ALIGN() . = ALIGN(32) > + > /* The actual configuration determine if the init/exit sections > * are handled as text/data or they can be discarded (which > * often happens at runtime) > @@ -166,7 +172,11 @@ > LIKELY_PROFILE() \ > BRANCH_PROFILE() \ > TRACE_PRINTKS() \ > + \ > + STRUCT_ALIGN(); \ > FTRACE_EVENTS() \ > + \ > + STRUCT_ALIGN(); \ > TRACE_SYSCALLS() > > /* > -- > 1.6.0.6 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/