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 7E5D7EE49A9 for ; Wed, 11 Sep 2024 13:50:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 031F694003E; Wed, 11 Sep 2024 09:50:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F249D940021; Wed, 11 Sep 2024 09:50:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DEBE894003E; Wed, 11 Sep 2024 09:50:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id C09AD940021 for ; Wed, 11 Sep 2024 09:50:14 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 6C22B81551 for ; Wed, 11 Sep 2024 13:50:14 +0000 (UTC) X-FDA: 82552591548.21.DD69704 Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by imf01.hostedemail.com (Postfix) with ESMTP id 5055A40009 for ; Wed, 11 Sep 2024 13:50:10 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=ellerman.id.au header.s=201909 header.b=b6rCWOCp; spf=pass (imf01.hostedemail.com: domain of mpe@ellerman.id.au designates 150.107.74.76 as permitted sender) smtp.mailfrom=mpe@ellerman.id.au; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1726062584; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=lpBzbgWttHYkkQ41sscZ0OOoe2UyQs048+I1EnGEnbs=; b=ZfEuzRSfquAzdlw+Je8S/g0Vz+VCigOUFQDrkapAGpV7ajYmzqpZT8AcSNrRK1pikAWK6g +hGJK3iD2PErF9PlaDtoNiXsgseDWXeaC0YLIs2WGf9pC3pIrgTKyQPsCREQ7qwUFDRago M3XcoGqjdpvSO9xtYB8aXKxpHFd9zzk= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=ellerman.id.au header.s=201909 header.b=b6rCWOCp; spf=pass (imf01.hostedemail.com: domain of mpe@ellerman.id.au designates 150.107.74.76 as permitted sender) smtp.mailfrom=mpe@ellerman.id.au; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1726062584; a=rsa-sha256; cv=none; b=5YvQkVENK66o/XzO/t+ky+TEn+yM9aIDZcVz9tZrNoa6EqA+FC1hsjLBLDCIPnsYcg/ldw ydxhQiPkCxQp/cdgJs8MPkUbzUTzFDBCPL9j3yHgpu78Es7Q9NVHzZ3JfFOpCxgZv8wQQJ +ZX4zHS+mKmUaLPi4E0exgxmXhbog6g= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1726062608; bh=lpBzbgWttHYkkQ41sscZ0OOoe2UyQs048+I1EnGEnbs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=b6rCWOCpsR6QTZU68icEH6ah28jcqnXyKEGoUH0ohvJRhp/Mm3QMMNf7cz1PRZVJk qZnhrbEZQSdtE52b5m7L8yLtR87aHqZ9Y3U05UdXnLFYWT6W/Gva4cteQod4+pDscF iq9WFey+WYHFyzKGuoKHndEZ0KUL/iVZ82dFsXKNk1jKIZA3FOkaV87mvcYAUlbhmC QSm0f+2sovoKzmv6FOXBVgqAL9iWpzg6XychwCtrVghD79R/XByY5tXAMuIaTpHV5g 0oMsPLM4pI21UqirAlt8h43LH7OPXzxNCN5RDMbPbQlnnQRUFay141JPyB1XvhsCzO l8YWjW9+O5+hg== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mail.ozlabs.org (Postfix) with ESMTPSA id 4X3hlf1JyWz4x8D; Wed, 11 Sep 2024 23:50:06 +1000 (AEST) From: Michael Ellerman To: Arnd Bergmann , Charlie Jenkins , Lorenzo Stoakes Cc: Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King , guoren , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , "James E . J . Bottomley" , Helge Deller , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , "David S . Miller" , Andreas Larsson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Muchun Song , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , shuah , Christoph Hellwig , Michal Hocko , "Kirill A. Shutemov" , Chris Torek , Linux-Arch , linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, "linux-csky@vger.kernel.org" , loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-abi-devel@lists.sourceforge.net Subject: Re: [PATCH RFC v3 1/2] mm: Add personality flag to limit address to 47 bits In-Reply-To: <89d21669-8daa-4225-b6d2-33d439ebd746@app.fastmail.com> References: <20240905-patches-below_hint_mmap-v3-0-3cd5564efbbb@rivosinc.com> <20240905-patches-below_hint_mmap-v3-1-3cd5564efbbb@rivosinc.com> <9fc4746b-8e9d-4a75-b966-e0906187e6b7@app.fastmail.com> <58f39d58-579e-4dd3-8084-baebf86f1ae0@lucifer.local> <7be08ea9-f343-42da-805f-e5f0d61bde26@app.fastmail.com> <016c7857-9ea8-4333-96e6-3ae3870f375f@lucifer.local> <89d21669-8daa-4225-b6d2-33d439ebd746@app.fastmail.com> Date: Wed, 11 Sep 2024 23:50:05 +1000 Message-ID: <87zfoeqoz6.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Stat-Signature: figm1o5tgus8ozhnbe9id3516m4mc7cx X-Rspamd-Queue-Id: 5055A40009 X-Rspamd-Server: rspam11 X-HE-Tag: 1726062610-609955 X-HE-Meta: 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 rS0LI7ys ug0V/IWIn6Mb0OkUWWuPjlhMKiiSkQUuaBeKL/H/zcwYETtNoymvH4XENC2p7I42w0wXNNmb3Oa5tFBRJdniiR3i8qLpzXQp2i5o4H1chWF7nFZh0J1thOp0Hh+j5fOvaMspxD7VUtQyjOkljNcF2hrbDY251t3WJFy63WIfl0WaOOds6epZFxOnR3BCGUBgpuV1FNBtn2fRvhWtLTUqnwp01kWXGgAraHu40XQTbea14juQv9HgkUD7Gs5HoZRQ8Wi93XJU5+lKo9d6Eey+4BIwykO/XS8bbUm/W 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: List-Subscribe: List-Unsubscribe: "Arnd Bergmann" writes: > On Mon, Sep 9, 2024, at 23:22, Charlie Jenkins wrote: >> On Fri, Sep 06, 2024 at 10:52:34AM +0100, Lorenzo Stoakes wrote: >>> On Fri, Sep 06, 2024 at 09:14:08AM GMT, Arnd Bergmann wrote: >>> The intent is to optionally be able to run a process that keeps higher bits >>> free for tagging and to be sure no memory mapping in the process will >>> clobber these (correct me if I'm wrong Charlie! :) ... > Let's see what the other architectures do and then come up with > a way that fixes the pointer tagging case first on those that are > broken. We can see if there needs to be an extra flag after that. > Here is what I found: > > - x86_64 uses DEFAULT_MAP_WINDOW of BIT(47), uses a 57 bit > address space when an addr hint is passed. > - arm64 uses DEFAULT_MAP_WINDOW of BIT(47) or BIT(48), returns > higher 52-bit addresses when either a hint is passed or > CONFIG_EXPERT and CONFIG_ARM64_FORCE_52BIT is set (this > is a debugging option) > - ppc64 uses a DEFAULT_MAP_WINDOW of BIT(47) or BIT(48), > returns 52 bit address when an addr hint is passed It's 46 or 47 depending on PAGE_SIZE (4K or 64K): $ git grep "define DEFAULT_MAP_WINDOW_USER64" arch/powerpc/include/asm/task_size_64.h arch/powerpc/include/asm/task_size_64.h:#define DEFAULT_MAP_WINDOW_USER64 TASK_SIZE_128TB arch/powerpc/include/asm/task_size_64.h:#define DEFAULT_MAP_WINDOW_USER64 TASK_SIZE_64TB cheers