From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBD48C4321E for ; Mon, 10 Sep 2018 17:45:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 872BB2086A for ; Mon, 10 Sep 2018 17:45:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=agner.ch header.i=@agner.ch header.b="niYr6EJW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 872BB2086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=agner.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728832AbeIJWkt (ORCPT ); Mon, 10 Sep 2018 18:40:49 -0400 Received: from mail.kmu-office.ch ([178.209.48.109]:54458 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726906AbeIJWkt (ORCPT ); Mon, 10 Sep 2018 18:40:49 -0400 Received: from webmail.kmu-office.ch (unknown [IPv6:2a02:418:6a02::a3]) by mail.kmu-office.ch (Postfix) with ESMTPSA id 82F475C0414; Mon, 10 Sep 2018 19:45:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=agner.ch; s=dkim; t=1536601533; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0ZWp9KqgbQjuOfzRPLcdogaqdPH6Fd/f5vgZjN9g17s=; b=niYr6EJWOmRdMezY+sIUyxPnftn1R6svpVZ2mH6eO/P8koTkhL548ASOk9VUrpvTvVrQ9O iJPNpc4f1IWjZL+4d9KipYfBl3ZJIyft4xe1WDMrqs4pswsWwp1tX7fgtgX8C53zsiqWoA THIL3j6lRjSXIAsgesVV9CFIJHWKbQk= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Mon, 10 Sep 2018 10:45:33 -0700 From: Stefan Agner To: Miguel Ojeda Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Rasmus Villemoes , Luc Van Oostenryck , Eli Friedman , Christopher Li , Kees Cook , Ingo Molnar , Geert Uytterhoeven , Arnd Bergmann , Greg Kroah-Hartman , Masahiro Yamada , Joe Perches , Dominique Martinet , Nick Desaulniers , linux-sparse@vger.kernel.org, linux-kernel-owner@vger.kernel.org Subject: Re: [PATCH v4 05/13] Compiler Attributes: naked was fixed in gcc 4.6 In-Reply-To: <20180908212459.19736-6-miguel.ojeda.sandonis@gmail.com> References: <20180908212459.19736-1-miguel.ojeda.sandonis@gmail.com> <20180908212459.19736-6-miguel.ojeda.sandonis@gmail.com> Message-ID: X-Sender: stefan@agner.ch User-Agent: Roundcube Webmail/1.3.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 08.09.2018 14:24, Miguel Ojeda wrote: > Commit 9c695203a7dd ("compiler-gcc.h: gcc-4.5 needs noclone > and noinline on __naked functions") added noinline and noclone > as a workaround for a gcc 4.5 bug, which was resolved in 4.6.0. > > Since now the minimum gcc supported version is 4.6, > we can clean it up. > > See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44290 > and https://godbolt.org/z/h6NMIL > > Cc: Rasmus Villemoes > Cc: Luc Van Oostenryck > Cc: Eli Friedman > Cc: Christopher Li > Cc: Kees Cook > Cc: Ingo Molnar > Cc: Geert Uytterhoeven > Cc: Arnd Bergmann > Cc: Greg Kroah-Hartman > Cc: Masahiro Yamada > Cc: Joe Perches > Cc: Dominique Martinet > Cc: Nick Desaulniers > Cc: Linus Torvalds > Cc: linux-sparse@vger.kernel.org > Signed-off-by: Miguel Ojeda > --- > include/linux/compiler-gcc.h | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h > index 76f4907ef707..4cd5e9264bce 100644 > --- a/include/linux/compiler-gcc.h > +++ b/include/linux/compiler-gcc.h > @@ -77,14 +77,8 @@ > * to trace naked functions because then mcount is called without > * stack and frame pointer being set up and there is no chance to > * restore the lr register to the value before mcount was called. I think this is also no longer required since GCC 4.6 and newer only have the new mcount interface: https://lore.kernel.org/lkml/20180826214022.4889-1-stefan@agner.ch/T/#u That said, I am not sure whether it is a good idea to enable tracing for naked functions even with the mcount interface. -- Stefan > - * > - * The asm() bodies of naked functions often depend on standard calling > - * conventions, therefore they must be noinline and noclone. > - * > - * GCC 4.[56] currently fail to enforce this, so we must do so ourselves. > - * See GCC PR44290. > */ > -#define __naked __attribute__((__naked__)) noinline __noclone notrace > +#define __naked __attribute__((__naked__)) notrace > > #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)