From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755702Ab0HIIH7 (ORCPT ); Mon, 9 Aug 2010 04:07:59 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:45665 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755611Ab0HIIH5 (ORCPT ); Mon, 9 Aug 2010 04:07:57 -0400 Date: Mon, 9 Aug 2010 10:07:23 +0200 From: Ingo Molnar To: Namhyung Kim Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds , Rusty Russell Subject: Re: [PATCH] x86: remove __phys_reloc_hide Message-ID: <20100809080723.GD24221@elte.hu> References: <1281303490-390-1-git-send-email-namhyung@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1281303490-390-1-git-send-email-namhyung@gmail.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 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 * 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? Ingo