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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 5F27EC31E45 for ; Thu, 13 Jun 2019 15:32:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E3392082C for ; Thu, 13 Jun 2019 15:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728585AbfFMPcE (ORCPT ); Thu, 13 Jun 2019 11:32:04 -0400 Received: from relay.sw.ru ([185.231.240.75]:40084 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728554AbfFMKub (ORCPT ); Thu, 13 Jun 2019 06:50:31 -0400 Received: from [172.16.25.12] by relay.sw.ru with esmtp (Exim 4.92) (envelope-from ) id 1hbNJM-0000cp-C9; Thu, 13 Jun 2019 13:50:28 +0300 Subject: Re: [PATCH v3 2/3] x86: Use static_cpu_has in uaccess region to avoid instrumentation To: Marco Elver , peterz@infradead.org, dvyukov@google.com, glider@google.com, andreyknvl@google.com, mark.rutland@arm.com, hpa@zytor.com Cc: 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 References: <20190531150828.157832-1-elver@google.com> <20190531150828.157832-3-elver@google.com> From: Andrey Ryabinin Message-ID: Date: Thu, 13 Jun 2019 13:50:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190531150828.157832-3-elver@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/31/19 6:08 PM, 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). > > Signed-off-by: Marco Elver > Suggested-by: H. Peter Anvin Reviewed-by: Andrey Ryabinin