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=-8.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 B2569C31E45 for ; Thu, 13 Jun 2019 15:48:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 877E520851 for ; Thu, 13 Jun 2019 15:48:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="RvVfgl22" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389231AbfFMPsJ (ORCPT ); Thu, 13 Jun 2019 11:48:09 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:50160 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726541AbfFMJVh (ORCPT ); Thu, 13 Jun 2019 05:21:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=KNxPWlWuxnDwYXMMhXWadjBNeF5Uv67xMzgxslH4spI=; b=RvVfgl22PpGBJDNLkXFMiMjLs u8EyR5xVLEFRoaxMXVmWkgS3oWG0cFcTq94IwDR7upEolKf/rdjFDkLH8uYoayUuNpIviET6kY9/8 tbb/DBMzpHXF5XxnKNtjV46uRJS0UaH/2h+CpUg5R5DWhCY6Q++wILsSOi+cl7IF0vBSJ90GTuunC bCj7nyddUBt0KfPVT3aZpEv8LRFzH7VdqyrF41olQSipswiMd3oI+WWxkn21LhC+JiiYWDkDaKY/j GfjiqyLLH4ow9K7AOYgLJrGwE8KfWhs1zsCVQlmoIR2Jbf7d9y07Ie9yPKBC1GIea5Nu6gR4dOV/y zHArEAOGg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hbLvA-0000K1-OV; Thu, 13 Jun 2019 09:21:24 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 33A9D209C844F; Thu, 13 Jun 2019 11:21:23 +0200 (CEST) Date: Thu, 13 Jun 2019 11:21:23 +0200 From: Peter Zijlstra To: Marco Elver Cc: aryabinin@virtuozzo.com, dvyukov@google.com, glider@google.com, andreyknvl@google.com, mark.rutland@arm.com, hpa@zytor.com, corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, arnd@arndb.de, jpoimboe@redhat.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, kasan-dev@googlegroups.com Subject: Re: [PATCH v3 2/3] x86: Use static_cpu_has in uaccess region to avoid instrumentation Message-ID: <20190613092123.GO3402@hirez.programming.kicks-ass.net> References: <20190531150828.157832-1-elver@google.com> <20190531150828.157832-3-elver@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190531150828.157832-3-elver@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 31, 2019 at 05:08:30PM +0200, Marco Elver wrote: > This patch is a pre-requisite for enabling KASAN bitops instrumentation; > using static_cpu_has instead of boot_cpu_has avoids instrumentation of > test_bit inside the uaccess region. With instrumentation, the KASAN > check would otherwise be flagged by objtool. > > For consistency, kernel/signal.c was changed to mirror this change, > however, is never instrumented with KASAN (currently unsupported under > x86 32bit). Acked-by: Peter Zijlstra (Intel) Thanks! > > Signed-off-by: Marco Elver > Suggested-by: H. Peter Anvin > --- > Changes in v3: > * Use static_cpu_has instead of moving boot_cpu_has outside uaccess > region. > > Changes in v2: > * Replaces patch: 'tools/objtool: add kasan_check_* to uaccess > whitelist' > --- > arch/x86/ia32/ia32_signal.c | 2 +- > arch/x86/kernel/signal.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c > index 629d1ee05599..1cee10091b9f 100644 > --- a/arch/x86/ia32/ia32_signal.c > +++ b/arch/x86/ia32/ia32_signal.c > @@ -358,7 +358,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, > put_user_ex(ptr_to_compat(&frame->uc), &frame->puc); > > /* Create the ucontext. */ > - if (boot_cpu_has(X86_FEATURE_XSAVE)) > + if (static_cpu_has(X86_FEATURE_XSAVE)) > put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); > else > put_user_ex(0, &frame->uc.uc_flags); > diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c > index 364813cea647..52eb1d551aed 100644 > --- a/arch/x86/kernel/signal.c > +++ b/arch/x86/kernel/signal.c > @@ -391,7 +391,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, > put_user_ex(&frame->uc, &frame->puc); > > /* Create the ucontext. */ > - if (boot_cpu_has(X86_FEATURE_XSAVE)) > + if (static_cpu_has(X86_FEATURE_XSAVE)) > put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); > else > put_user_ex(0, &frame->uc.uc_flags); > -- > 2.22.0.rc1.257.g3120a18244-goog >