linux-kernel - Re: [PATCH RFC 1/2] Makefile: Never use -fno-omit-frame-pointer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 14 Jul 2009 17:37:16 +0400
From:	Anton Vorontsov <avorontsov@...mvista.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org,
	Steven Rostedt <srostedt@...hat.com>,
	Sam Ravnborg <sam@...nborg.org>
Subject: Re: [PATCH RFC 1/2] Makefile: Never use -fno-omit-frame-pointer

On Wed, Jun 17, 2009 at 12:16:30AM +0400, Anton Vorontsov wrote:
> According to Segher Boessenkool and GCC manual, -fomit-frame-pointer
> is only the default when optimising on archs/ABIs where it doesn't
> hinder debugging and -pg. So, we do not get it by default on x86,
> not at any optimisation level.
> 
> On the other hand, *using* -fno-omit-frame-pointer causes gcc to
> produce buggy code on PowerPC targets.
> 
> If Segher and GCC manual are right, this patch should be a no-op
> for all arches except PowerPC, where the patch fixes gcc issues.
> 
> Signed-off-by: Anton Vorontsov <avorontsov@...mvista.com>
> ---
> 
> See this thread for more discussion:
> http://osdir.com/ml/linux-kernel/2009-05/msg01754.html
> 
> p.s.
> Obviously, I didn't test this patch on anything else but PPC32. ;-)
> 
> Segher, do you know if all GCC versions that we support for
> building Linux are behaving the way that GCC manual describe?

No news is good news... Ingo, can we merge this into -tip for testing?

Thanks,

>  Makefile |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index ea63667..70ad1ff 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -535,7 +535,7 @@ KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
>  endif
>  
>  ifdef CONFIG_FRAME_POINTER
> -KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls
> +KBUILD_CFLAGS	+= -fno-optimize-sibling-calls
>  else
>  KBUILD_CFLAGS	+= -fomit-frame-pointer
>  endif
> -- 
> 1.6.3.1
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@...ts.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev

-- 
Anton Vorontsov
email: cbouatmailru@...il.com
irc://irc.freenode.net/bd2
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/