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 BFE40C433EF for ; Wed, 11 May 2022 07:21:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 36B716B0073; Wed, 11 May 2022 03:21:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 31C3B6B0075; Wed, 11 May 2022 03:21:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 20C106B0078; Wed, 11 May 2022 03:21:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 0DD2A6B0073 for ; Wed, 11 May 2022 03:21:30 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id C8AC022020 for ; Wed, 11 May 2022 07:21:29 +0000 (UTC) X-FDA: 79452616698.03.48A5ECA Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf16.hostedemail.com (Postfix) with ESMTP id 802BB1800C2 for ; Wed, 11 May 2022 07:21:20 +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=nMRpbJleYc5yXSKfAh469GiqgmI5a5rlLDX2lTpL2HA=; b=tVWjkQb2cURhuPXrhSfCi+DTAI zH/u/Qvh49vdQmyr/ovrIE+n+bktaSIfepangYCiGD+WEBEK+K9uPGWj51UJM08ip//jTXsxoCK/M /iG3sRWfUXVUjew9igsnJxlQOxEodrqMRipiHGI1olAKKYTpHxC+hrity27hL3UDUMvocqt32RiV4 iUap+uYSaSpvUR4vFVC4a87yF3Jdi3SpY69BIpJpH0+e22TdktChgGbLF+H3fuNg1aFG5EfF2ljNt Wh3jOci1FfDJe5hQGO9m1wIpp3L+ui1CmD73RRXcl6FOGvb9+UyOPi5atBj07Y51DBMP1qp9Ysach +KXZsXRQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1noges-005E93-2L; Wed, 11 May 2022 07:21:18 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 7F985980E3A; Wed, 11 May 2022 09:21:16 +0200 (CEST) Date: Wed, 11 May 2022 09:21:16 +0200 From: Peter Zijlstra To: "Kirill A. Shutemov" Cc: 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: [RFCv2 05/10] x86/mm: Provide untagged_addr() helper Message-ID: <20220511072116.GT76023@worktop.programming.kicks-ass.net> References: <20220511022751.65540-1-kirill.shutemov@linux.intel.com> <20220511022751.65540-7-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220511022751.65540-7-kirill.shutemov@linux.intel.com> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 802BB1800C2 X-Stat-Signature: ga45fyop5bgg66c484wyzx64o3w9k9a4 X-Rspam-User: Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=tVWjkQb2; spf=none (imf16.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: 1652253680-510936 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 Wed, May 11, 2022 at 05:27:46AM +0300, Kirill A. Shutemov wrote: > +#define __untagged_addr(addr, n) \ > + ((__force __typeof__(addr))sign_extend64((__force u64)(addr), n)) > + > +#define untagged_addr(addr) ({ \ > + u64 __addr = (__force u64)(addr); \ > + if (__addr >> 63 == 0) { \ > + if (current->thread.features & X86_THREAD_LAM_U57) \ > + __addr &= __untagged_addr(__addr, 56); \ > + else if (current->thread.features & X86_THREAD_LAM_U48) \ > + __addr &= __untagged_addr(__addr, 47); \ > + } \ > + (__force __typeof__(addr))__addr; \ > +}) Assuming you got your bits in hardware order: u64 __addr = addr; if ((s64)__addr >= 0) { int lam = (current->thread.features >> X86_THREAD_LAM_U57) & 3; if (lam) __addr &= sign_extend64(__addr, 65 - 9*lam); } __addr; has less branches on and should definitely result in better code (or I need more morning juice). > + > +#define untagged_ptr(ptr) ({ \ > + u64 __ptrval = (__force u64)(ptr); \ > + __ptrval = untagged_addr(__ptrval); \ > + (__force __typeof__(*(ptr)) *)__ptrval; \ > +}) > #endif /* !__ASSEMBLY__ */ > > #ifdef CONFIG_X86_VSYSCALL_EMULATION > -- > 2.35.1 >