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 BB12DC38142 for ; Fri, 27 Jan 2023 05:36:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F408F8E0001; Fri, 27 Jan 2023 00:36:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EF0806B0072; Fri, 27 Jan 2023 00:36:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DDF748E0001; Fri, 27 Jan 2023 00:36:26 -0500 (EST) 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 CF8556B0071 for ; Fri, 27 Jan 2023 00:36:26 -0500 (EST) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 9761FA0354 for ; Fri, 27 Jan 2023 05:36:26 +0000 (UTC) X-FDA: 80399468772.10.B37AC83 Received: from mail-ej1-f51.google.com (mail-ej1-f51.google.com [209.85.218.51]) by imf28.hostedemail.com (Postfix) with ESMTP id CA80BC0005 for ; Fri, 27 Jan 2023 05:36:24 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=iV2nzANh; spf=pass (imf28.hostedemail.com: domain of jeffxu@chromium.org designates 209.85.218.51 as permitted sender) smtp.mailfrom=jeffxu@chromium.org; dmarc=pass (policy=none) header.from=chromium.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1674797784; 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=TpOphuzy2a3NFyLxvfyqEazARXycnC0W77+P8CV8Fhs=; b=QlByxjO9pCdvyXzkMD8eNlKo4ww2mSXbgW6LtttTXZCRle6HpXzt/m8wmZ3mQNALNHcLbv W2stWn16balbCAnnjLQKWi6jmnIM845dgnwFnFTk/lKpOE5wdCqrfJ99dFbJSCz2M8b75K hkY4Yxk982BSomCAsy3gKNCMkhjANk0= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=iV2nzANh; spf=pass (imf28.hostedemail.com: domain of jeffxu@chromium.org designates 209.85.218.51 as permitted sender) smtp.mailfrom=jeffxu@chromium.org; dmarc=pass (policy=none) header.from=chromium.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1674797785; a=rsa-sha256; cv=none; b=kPvEtwSLtxPLyuY6KPECzJLznaEjkAmFOoVpGfa1CyY3tI//aklmNZgb+H441OLXuxERYz v7ycEuNiC2pB9NRQeuVihBRNAgGjBwVneOXHXql0bI6sPS+vvnDmKRyX0Ybs5DHQy8TJH1 xzQX4shBYygx44Kn7wcG2eApbN/ciog= Received: by mail-ej1-f51.google.com with SMTP id qx13so10709664ejb.13 for ; Thu, 26 Jan 2023 21:36:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=TpOphuzy2a3NFyLxvfyqEazARXycnC0W77+P8CV8Fhs=; b=iV2nzANhQM1lA7C39xTBX2tUeS5H1sRA19kCTpfC/YBmeb4xfkisC9xZgKs0ZEE+iN SKXdENQUwmyAfZcA2mfQo1ZBiTw/ZQLsC+66a3TTrkvuqpgCGehdYbojKBfwq3io7/kl DKuc/Bq8NdRNFOajd3bZv+aYRuielN//mlYn8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=TpOphuzy2a3NFyLxvfyqEazARXycnC0W77+P8CV8Fhs=; b=X14HKAwAcz4Jj/f0NGHJHYLRoqFuY2n8A0cAVzQ22vmY8tKsu4egaMiPqk6zttwIkS tIdEz3xYizlB2DmNnfpRoLxYD1lIRUV++DlfrNwyFIa5ea2+rpmfU0YR1YXB+NjpSfWG n+T+S4ERA0FbAF+e0hQXN8GRgsnmfq1L9YN7bzq6xfTbdHZ78ygA/tG/9nr9Yn7BSDuX KA7iQpdRgPco+TcRXemWYOUR7AnCLijQ9MnQiie6YVPdZyovHYDulTUehNeAjSxLTlcG URWcs/iMcLO14tXemqtmIDvToAP31AQyIbe6AGh9nOEk1XyCE+nDhV4mQS9xJ1NMlYhR dEIw== X-Gm-Message-State: AFqh2koCnp5oJyI2Lxwty4DihTxS/My6A8SeSn+hRYjlCNaD3vt3MDfH R6T6AG98e8YWrTRijTNTT51Oy4EPpIKhsj0jGxckOA== X-Google-Smtp-Source: AMrXdXuHQ8d+lySL2+OYmZH54/Hx7h1SdqtpNukoIsgMDKlnqp6MWQRreTNUsS2Fx6SlBQYlbEiHyYIfbC00ZcOg594= X-Received: by 2002:a17:906:4988:b0:871:e963:1508 with SMTP id p8-20020a170906498800b00871e9631508mr6516100eju.185.1674797783148; Thu, 26 Jan 2023 21:36:23 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Jeff Xu Date: Thu, 26 Jan 2023 21:36:11 -0800 Message-ID: Subject: Re: x86/pkeys in early kernel version To: Dave Hansen , me@kylehuey.com Cc: linux-mm@kvack.org, =?UTF-8?Q?Stephen_R=C3=B6ttger?= , "tglx@linutronix.de" , Jorge Lucangeli Obes , Kees Cook Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: hatcu378th4w4opgt1xyi94skc59o6sm X-Rspamd-Queue-Id: CA80BC0005 X-HE-Tag: 1674797784-978466 X-HE-Meta: U2FsdGVkX1+vP46UZrUzxcsl42RZyAubIDF4bW6x86KJIItd6MnG0p+rVOLp6NkQ9W62TwjpvXaRS/Uw/by0rWLTT0m4OJt4vxsCtCFyYPxSjnz43L8ZJLSgRepdt2kDoEoGJTVf85xQ6YaC5sUq+fzj4l+e0PSoMznWxC5plwuTcgChmXAFrKkb9TiGnlLXtxZCScG7Rn9ek5BTunsdeLDN6lbXZmc2MSAFRaR5b8d3lCfw/XLBCKgkwhnDL5K+jGDg2d2it6EblAgefeNqekCKMOOdr2uTDioElO+zYIU0XGPpltA/ATrDN/L+FSeJgJrYsXtLrPB61qdaiQ1LvGSEpSQGbogK1fGr0FVTowo8U2JdspaO/4eFaMlh0gqNZomcQlgtZqfJSXwF9wzp23WBumaovbU7NZKfS2mM9fQkuWeh+5qYqGXQs9rnU77ScSc99XYTa9mTJ3qyd4Uw35S8+I+N3MF18FbBW8bHNrNmWqub38bKMNqjp7bt7mwKcOK8eaHrAPvrY/lXtWCc3/UO23AjaPTjCzvV51kydXveS5kNXHxsYmUUIdaY+8w+ZWI5xIUjP7Tp280QRdw+9K2y4jMwb1/Y1aDbCRBXHzSMVRP7efih6KZqaR6Rn/FI/XXtdA6lTPv+dcAHC/qsFxLDTqix/3/EjE7TQojm0xbQgftXUslzhASFYi0W8JgZqSA1p7+QpLXJvY3V/R2o4EyhnABIVEYg82Nk3xC9jfcxYbyA7SXyOeqmV/rQHW2aIW8cwImr1Qela4hZ2Sb13TE5gR/SPpkgQ4YgZPziMEkp2gKTtPZBxND08xoVoQqIhP3RmlsDKDTTX1JRvSBr5ddt4pHOU7S3hIn8jA0HWZgccdIQFH48uTkHhnSYxzeSQLpEtpnyZ96tX2EdrrQlNdkmF31ClgjIGflE9KiAOlmPQm0gIpoguXMSRlruVmcymh/5l4XXytA8HVL8Qix 67OLyD68 gxLOInyw52aJN89dwtWujw1FXxuAx/jayrt/GrdQYwS8FLT4caaAjJGfwIGXE1fodNceand7dPPXuLZ+8C4xYFP69ULhBqV23//42LQpDk4sAybrd77qV7P0iTd3CrC/+UxGcxWNe8xwyMOEcLkWqgFPjKZ5SxormE4kBqomCPlRRXisClc6ekLOycJtoaQNvaLSLUd/DYW209nOEuBEkzYp9NISoee6+7IyUnVI9r54uxqYQY6OR1r28BgRbvunTR+n1Eet/qujD5pfxN+rDYiIhae4+PPCcjcgi6dZcO9uYYWe78vEFV9bEQ1vkRTmpJWvuo0Am0bd3obGTU3ag7mxpMhAE2ablPSAYiGo4US7C375AQ9286fMA8w9SXuZsxxtr42iMgiVh3HX15ufyXIbIA4SV/FHJdGyVnKvNPvaZ84A= 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, Jan 25, 2023 at 5:43 PM Jeff Xu wrote: > > On Wed, Jan 25, 2023 at 11:13 AM Dave Hansen wrote: > > > > On 1/25/23 11:02, Jeff Xu wrote: > > > I'm investigating if there is a need to backport x86/pkeys > > > fix/feature into earlier kernel versions, Chrome is starting to use > > > PKEY in x86, and I hope experts here can give advice on this. > > > > > > For background, ChromeOS regularly syncs with upstream kernel > > > versions, and has production that uses 4.4/4.14/4.19/5.4/5.10/5.15. > > To be honest, I haven't got the foggiest idea what you need to backport. > > I can barely keep track of mainline. > > > > Are there really production 4.4 kernels that you need to run on > > pkey-capable hardware? That would mean running a 2015-era kernel on a > > CPU released in late 2020. I think Q3'2020 is when the 11th gen CPUs > > came out which were the first non-server CPUs that had pkeys. > > > Thanks! > For 11th gen CPUs, chromebook uses 5.4 and above, so that eliminate > half of the versions. > > > On a positive note, the pkeys selftest has been pretty consistently > > updated as we find bugs. I'd be curious how well a mainline version of > > that selftests runs on old kernels. But, I'm too scared to find out > > what's down that particular rabbit hole myself. > I took the latest selftest from main and run on 5.15 kernel, all passed except test_ptrace_modifies_pkru assert() at protection_keys.c::1623 test_nr: 20 iteration: 1 Is there a bugfix for the ptrace area ? Thanks > I can start with 5.10 or 5.15, it seems there are quite some changes though, > for example, this one by Thomas > https://lore.kernel.org/lkml/20210623120127.327154589@linutronix.de/ > > My question is, if I have to pick a version that doesn't require a lot > of backporting, > and functionality is stable enough, what version would this be ? 5.4/5.10/5.15 ? > > -Jeff