Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754679Ab0HIS5K (ORCPT ); Mon, 9 Aug 2010 14:57:10 -0400 Received: from terminus.zytor.com ([198.137.202.10]:53050 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753771Ab0HIS5J (ORCPT ); Mon, 9 Aug 2010 14:57:09 -0400 Message-ID: <4C604F70.1040902@zytor.com> Date: Mon, 09 Aug 2010 11:56:48 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.7) Gecko/20100720 Fedora/3.1.1-1.fc13 Thunderbird/3.1.1 MIME-Version: 1.0 To: Ingo Molnar CC: Namhyung Kim , Thomas Gleixner , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds , Rusty Russell Subject: Re: [PATCH] x86: remove __phys_reloc_hide References: <1281303490-390-1-git-send-email-namhyung@gmail.com> <20100809080723.GD24221@elte.hu> In-Reply-To: <20100809080723.GD24221@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1458 Lines: 38 On 08/09/2010 01:07 AM, Ingo Molnar wrote: > > * Namhyung Kim wrote: > >> remove unnecessary use of RELOC_HIDE(). It only does simple addition of ptr >> and offset, and in this case, offset 0, does nothing. It does NOT do anything >> with linker relocation things. I could find no reason to use it. >> >> The only user of __phys_reloc_hide() was __pa_symbol() so it can be removed >> safely here. >> >> Signed-off-by: Namhyung Kim >> --- >> arch/x86/include/asm/page.h | 5 ++--- >> arch/x86/include/asm/page_32.h | 1 - >> arch/x86/include/asm/page_64_types.h | 1 - >> 3 files changed, 2 insertions(+), 5 deletions(-) > > We do this as a general Voodoo barrier against GCC miscompilations. > > You are right that it's largely moot by today (and especially so on x86 - i > only remember a single instance of miscompilation that Rusty mentioned few > years ago, and that was on powerpc), but the wrapper is simple enough, so > unless there's some real tangible improvement in the binary output we might as > well keep it. > > Peter, what do you think? > I agree... I suspect it might make some difference for gcc 3 stragglers. -hpa -- 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/