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=-13.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_PDS_SHORTFWD_URISHRT_QP, USER_IN_DEF_DKIM_WL autolearn=no 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 1BFB9C433EF for ; Wed, 22 Sep 2021 20:03:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B631B611CA for ; Wed, 22 Sep 2021 20:03:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B631B611CA Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 51BC1900003; Wed, 22 Sep 2021 16:03:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4CB37900002; Wed, 22 Sep 2021 16:03:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3450B900003; Wed, 22 Sep 2021 16:03:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0184.hostedemail.com [216.40.44.184]) by kanga.kvack.org (Postfix) with ESMTP id 25B9F900002 for ; Wed, 22 Sep 2021 16:03:45 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id CFA22182CA8FD for ; Wed, 22 Sep 2021 20:03:44 +0000 (UTC) X-FDA: 78616284768.11.692DAE2 Received: from mail-ot1-f49.google.com (mail-ot1-f49.google.com [209.85.210.49]) by imf15.hostedemail.com (Postfix) with ESMTP id 77E46D00009B for ; Wed, 22 Sep 2021 20:03:44 +0000 (UTC) Received: by mail-ot1-f49.google.com with SMTP id h9-20020a9d2f09000000b005453f95356cso5166876otb.11 for ; Wed, 22 Sep 2021 13:03:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=kEm2SFVN0qjXNkIh8Gnf2RTGMo+YdlReLvRWFG8knT4=; b=QHWBEI3tAorbb+ikzEGeckYHlgv6S7VPBtQkLNIh9N4JefCrneXNEJyB6+zD8eEsfs 3cRSB0G3ucw/9V8jCN2+mKGR8QBJy0xOIkf0mCGyhJAII0Slfdty2HH3+f5OGEJVrwPU UMOTvpyV33Wfj0JN4UqtxX0vDO9orCS7IF3I/zBWoyF5sXGuDkEcMkl+zwniw2OEra0J GBpz28YNvOQOkSkS4b6MBzfjNtcjyExSXHKm4Cp1heCXmwErbvkIeNCB78owVLt4qpPn rba2jeNrjm4wpT8w5FuTeKAx4d3qgZY7wx/HHzMqv8wMGjyWCaOD2R9EtzufCYuFUpH9 kWzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=kEm2SFVN0qjXNkIh8Gnf2RTGMo+YdlReLvRWFG8knT4=; b=pbEqRMKIiCGYF3zqQtMfubOcICtN2fWL9IGWsOGoNpQ9CiRRXoXh1zaQOZL/ctnffW /3AStaa1XnMWakl6I9m02wBSeCZ9/7iREX0pzrWfp6ra2s9c7/L1D2hRKn6M0kYU6Qqj jhxLHxKdC3u5Bt0msPWWKQ6IjAOvaIZB4ujbGF3MeVn6KnlwQHt7K9egoikcCDqKuyot Num0D1hdMq45q5vXN8sKgCfH8Gp0+qE/dC3naEGd8KKC+KnPhcYSS+ozRHbckLiy6WZz 1DuGmqPi2nwnhGc6nWxTCZrFDAfFqPg/aElWvgP9CCaiNeg5xmtaj24D77SZX1kI64ZD 7/aQ== X-Gm-Message-State: AOAM530Emi+1Nq89aZNJj4yPSL4ryaLJyKerrIHCiN8q0SyEWWP4HCXe oX6RGVc9aoLybOm2bqVGWH6a0gl2nP1/7viHZeaYfw== X-Google-Smtp-Source: ABdhPJxToJ6KZIlOwD9Bmi0UBSQLp019+AgNAjB4oui3kk+79mrRQ6EylSpbFdbg0JsJBVg2bD29wC8hcHmg4YopGdc= X-Received: by 2002:a05:6830:82b:: with SMTP id t11mr820891ots.319.1632341023516; Wed, 22 Sep 2021 13:03:43 -0700 (PDT) MIME-Version: 1.0 References: <20210205151631.43511-1-kirill.shutemov@linux.intel.com> <20210207141104.ikxbdxhoisgqaoio@box> In-Reply-To: From: Dmitry Vyukov Date: Wed, 22 Sep 2021 22:03:32 +0200 Message-ID: Subject: Re: [RFC 0/9] Linear Address Masking enabling To: "Zhang, Xiang1" Cc: "H.J. Lu" , "Kirill A. Shutemov" , "Kirill A. Shutemov" , Dave Hansen , "Lutomirski, Andy" , Peter Zijlstra , "the arch/x86 maintainers" , Andrey Ryabinin , Alexander Potapenko , Catalin Marinas , Will Deacon , Andi Kleen , Linux-MM , LKML , "Carlos O'Donell" , Marco Elver , Taras Madan Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: 4ncgthcbxbg19scb3fpxr9c15r5a7n1y Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=QHWBEI3t; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf15.hostedemail.com: domain of dvyukov@google.com designates 209.85.210.49 as permitted sender) smtp.mailfrom=dvyukov@google.com X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 77E46D00009B X-HE-Tag: 1632341024-161620 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, 22 Sept 2021 at 14:54, Dmitry Vyukov wrote: > > On Wed, 22 Sept 2021 at 03:15, Zhang, Xiang1 wro= te: > > > > There are already in llvm.org. > > One of my old patch is https://reviews.llvm.org/D102472 which has been = committed by https://reviews.llvm.org/D102901 and https://reviews.llvm.org= /D109790 > > Hi Xiang, > > Good sanitizer patches are upstream! > > Please help me to understand the status of other pieces (H.J. you > probably talked about this yesterday, but I wasn't able to build a > complete picture during the talk, I think it will be useful to have > this in written form). > > 1. The presentation mentions "GCC: enable memory tagging with LAM in > x86 codegen". > What exactly is needed? Isn't LAM transparent for codegen? What's the > status in gcc? Does a corresponding change need to be done in llvm? > > 2. "Enable LAM in binutils". > This is already upstream in binutils 2.36, right? > > 3. The mentioned glibc patch: > http://patchwork.ozlabs.org/project/glibc/patch/20210211173711.71736-1-hj= l.tools@gmail.com/ > Not upstream yet, targeting glibc 2.34. Do we need any support in other libc's, e.g. Android bionic? > 4. "Avoid pointer operations incompatible with LAM. memmove: mask out > memory tags before comparing pointers". > Is this upstream? Where is the patch? Are there other similar patches? > > As a side note, regarding the memmove change: do we really need it? > Memory regions can overlap only if they come from the same > allocation/base object. If they come from different allocations, they > can't overlap (undefined behavior already). > > 5. Do we need any additional enabling changes in clang/llvm? > > 6. The kernel patches (this email thread) depend on the CET patches > (for the interface part only). And the CET patches is this, right? > https://lore.kernel.org/linux-doc/?q=3Dx86%2Fcet%2Fshstk > > 7. Do I miss anything else? > > H.J. please upload your slides here: > https://linuxplumbersconf.org/event/11/contributions/1010/ > It would help with links and copy-pasting text. > > FTR here is the link to the Plumbers talk: > https://youtu.be/zUw0ZVXCwoM?t=3D10456 > > Thank you > > > > BR > > Xiang > > > > -----Original Message----- > > From: H.J. Lu > > Sent: Wednesday, September 22, 2021 1:16 AM > > To: Dmitry Vyukov > > Cc: Kirill A. Shutemov ; Kirill A. Shutemov ; Dave Hansen ; Lu= tomirski, Andy ; Peter Zijlstra ; th= e arch/x86 maintainers ; Andrey Ryabinin ; Alexander Potapenko ; Catalin Marinas ; Will Deacon ; Andi Kleen ; Linux-MM ; LKML ; = Carlos O'Donell ; Marco Elver ; Taras = Madan ; Zhang, Xiang1 > > Subject: Re: [RFC 0/9] Linear Address Masking enabling > > > > On Tue, Sep 21, 2021 at 9:52 AM Dmitry Vyukov wrot= e: > > > > > > On Sun, 7 Feb 2021 at 15:11, Kirill A. Shutemov wrote: > > > > > > > > On Sun, Feb 07, 2021 at 09:24:23AM +0100, Dmitry Vyukov wrote: > > > > > On Fri, Feb 5, 2021 at 4:16 PM Kirill A. Shutemov > > > > > wrote: > > > > > > > > > > > > Linear Address Masking[1] (LAM) modifies the checking that is > > > > > > applied to 64-bit linear addresses, allowing software to use of > > > > > > the untranslated address bits for metadata. > > > > > > > > > > > > The patchset brings support for LAM for userspace addresses. > > > > > > > > > > > > The most sensitive part of enabling is change in tlb.c, where > > > > > > CR3 flags get set. Please take a look that what I'm doing makes= sense. > > > > > > > > > > > > The patchset is RFC quality and the code requires more testing > > > > > > before it can be applied. > > > > > > > > > > > > The userspace API is not finalized yet. The patchset extends AP= I > > > > > > used by > > > > > > ARM64: PR_GET/SET_TAGGED_ADDR_CTRL. The API is adjusted to not > > > > > > imply ARM > > > > > > TBI: it now allows to request a number of bits of metadata > > > > > > needed and report where these bits are located in the address. > > > > > > > > > > > > There's an alternative proposal[2] for the API based on Intel > > > > > > CET interface. Please let us know if you prefer one over anothe= r. > > > > > > > > > > > > The feature competes for bits with 5-level paging: LAM_U48 make= s > > > > > > it impossible to map anything about 47-bits. The patchset made > > > > > > these capability mutually exclusive: whatever used first wins. > > > > > > LAM_U57 can be combined with mappings above 47-bits. > > > > > > > > > > > > I include QEMU patch in case if somebody wants to play with the= feature. > > > > > > > > > > Exciting! Do you plan to send the QEMU patch to QEMU? > > > > > > > > Sure. After more testing, once I'm sure it's conforming to the hard= ware. > > > > > > A follow up after H.J.'s LPC talk: > > > https://linuxplumbersconf.org/event/11/contributions/1010/ > > > (also +Carlos) > > > > > > As far as I understood, this kernel series depends on the Intel CET p= atches. > > > > > > Where are these compiler-rt patches that block gcc support? > > > > Hi Xiang, > > > > Please share your compiler-rt changes for LAM. > > > > -- > > H.J.