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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A336BC433F5 for ; Thu, 12 May 2022 14:35:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0D43B6B0074; Thu, 12 May 2022 10:35:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 05C216B0075; Thu, 12 May 2022 10:35:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E3F636B0078; Thu, 12 May 2022 10:35:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id D07306B0074 for ; Thu, 12 May 2022 10:35:24 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id B5E7B3126E for ; Thu, 12 May 2022 14:35:24 +0000 (UTC) X-FDA: 79457338968.02.C0F605D Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf07.hostedemail.com (Postfix) with ESMTP id 82019400A7 for ; Thu, 12 May 2022 14:35:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=2H6oOa1Jm7efg8vMAP01Huzry7NOm7+jsbscO12jXSc=; b=qNMp9lA/tjtK+U8Y5Q5aoToURn 4ky/lfzh8PITgJopNm+26oJXcFvGZGwGViRjWwZMCPvo7zhlzyRU1phujiAKznYAi0+KA7eZ4M2Pg vwn75jgd+ehaSDWnLfr6Gn3ki7/fPY6B0+Ro9iE9bFWw97Y4kMISOleOfSX2aGzbPVg+Jk4WQJ64H mU43UkFm7MDRODr/dVE/8yKjo2EaQqA+J2cCuLtbeikumtJKJlU0EcyEyjMl20odnZzn6YR0X2SbX 6SQcM4hBu40I7i7e3DqmDLIAWxy1sM+vdaZXcjIlhtqat3CAUJTjDG5/sOEHP3JjwHkEe/NBEsfXb LzMsJYPw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1np9uO-006TT7-4P; Thu, 12 May 2022 14:35:16 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 6A0A130080B; Thu, 12 May 2022 16:35:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4D2AB201E235B; Thu, 12 May 2022 16:35:15 +0200 (CEST) Date: Thu, 12 May 2022 16:35:15 +0200 From: Peter Zijlstra To: David Laight Cc: "'Kirill A. Shutemov'" , Dave Hansen , Andy Lutomirski , "x86@kernel.org" , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: Implement Linear Address Masking support Message-ID: References: <20220511022751.65540-1-kirill.shutemov@linux.intel.com> <20220511022751.65540-2-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 82019400A7 X-Stat-Signature: hbmqs4abed8try4b6x3sne9uqh4t6cfc X-Rspam-User: Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="qNMp9lA/"; spf=none (imf07.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org; dmarc=none X-HE-Tag: 1652366117-139138 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, May 12, 2022 at 01:01:07PM +0000, David Laight wrote: > > +static inline int64_t sign_extend64(uint64_t value, int index) > > +{ > > + int shift = 63 - index; > > + return (int64_t)(value << shift) >> shift; > > +} > > Shift of signed integers are UB. The kernel uses -fno-strict-overflow, all the signed UB is gone.