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 DABD4C35FFC for ; Tue, 25 Mar 2025 13:14:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 97E9D280035; Tue, 25 Mar 2025 09:14:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 92D14280034; Tue, 25 Mar 2025 09:14:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7AA51280035; Tue, 25 Mar 2025 09:14:14 -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 56057280034 for ; Tue, 25 Mar 2025 09:14:14 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 4AC421603F0 for ; Tue, 25 Mar 2025 13:14:14 +0000 (UTC) X-FDA: 83260116828.21.EE0B590 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf28.hostedemail.com (Postfix) with ESMTP id 53EEBC0006 for ; Tue, 25 Mar 2025 13:14:12 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=NyPrZX2z; spf=pass (imf28.hostedemail.com: domain of guoren@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=guoren@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1742908452; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7bzJUIwY16l63QfKJmsiupVF7IYNqpkd3IzG9gYAALc=; b=loHzRw8Pc4W3mehGdDTE4Dgc+05QGKWSgpBhxdjr/K4PSmMbNQ2rahULvifHxeGQizhxEk +E0j0invx+O2EKGPCwknS4S1epvzWVo3noQQNBuXN/+7l9bmo3UGVysfTL5J2tvBXY5RJU 9KkMRI+ipTlSvQ1URD/rjc4zVVMTYqM= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=NyPrZX2z; spf=pass (imf28.hostedemail.com: domain of guoren@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=guoren@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1742908452; a=rsa-sha256; cv=none; b=39I9YlCYU4NK7raa0kwLWWpX54adlr3iwo+pfqhvQ80WnQel3FJt8Np9g4Sr9XnKizQbPl BrFuO6GEUSOrlrX3IAZg09VBKu5nlalZ+hRAdT8ZWxly73LhgcCNNsZYxEvM3fNYE6s9mY ydaZg/2e5eDCG6z36CXia3KfIMqnWss= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 9D288A490DC for ; Tue, 25 Mar 2025 13:08:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55384C4CEE4 for ; Tue, 25 Mar 2025 13:14:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742908451; bh=7bzJUIwY16l63QfKJmsiupVF7IYNqpkd3IzG9gYAALc=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=NyPrZX2zvYx4m3VH9Fc1wiiQCHtp81BxhFIgJErfM1e6iK8yvSerc4sfbMDBzx1kQ QplIQZnPOseIWFkTXjK02uSDnGG6Uzq1AYv5KPHeujZiOAlbpwn4SbWEHhmX/gy469 fFXR2na2foa9uxqRXn9AF0M+fongqdtMQAsDD80dHI5sfoaBLx23YVNceFsMWYKaVs C7/p11hnQkANTPBqtf0OU6Q+v+kaVBZb6VFrZLAR7m0krBlnMAO88LNmzTdnsOfaKI VpbZ0yXg04wccCBO9NlBypwixYU1z2XvmV1vo+KcGfLfjl1MuRnqI83HTSb88ieULT G+VRbIUrF/dSg== Received: by mail-wm1-f43.google.com with SMTP id 5b1f17b1804b1-43bb6b0b898so53855875e9.1 for ; Tue, 25 Mar 2025 06:14:11 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCWbg1h1YYwQbSNZmwNyuKutJGZ4Uh3AtTJXzA8Ekd5U7WTMQT70+7oMDNth+Y5L/ePi51Uc69g77g==@kvack.org X-Gm-Message-State: AOJu0YxAV3heFpE0SpN8XfVFbNA/X9NNiwWmJIs1+wKrm8VoL1/NAmXO RZ4iVmXfbwyZFxiqWwN4yiG7fBNDsXervTFr29kG1CdnGv0q2Ln874iMMpys0eJWDJsP5zhJ0jb JQeRjXiM3oKxT9J6Yk1XbCVKaYMY= X-Google-Smtp-Source: AGHT+IGfKexksGgX0maV0KTcsKLOGrgVH5YKmlbhOfh8iEjwSz3eKgWZcomNnjiD6N1+SrsmiEpO9V65lbI9UvtGx1A= X-Received: by 2002:a5d:59a2:0:b0:38f:6287:6474 with SMTP id ffacd0b85a97d-3997f8fc43dmr15193020f8f.15.1742908449922; Tue, 25 Mar 2025 06:14:09 -0700 (PDT) MIME-Version: 1.0 References: <20250325121624.523258-1-guoren@kernel.org> <20250325122640.GK36322@noisy.programming.kicks-ass.net> In-Reply-To: <20250325122640.GK36322@noisy.programming.kicks-ass.net> From: Guo Ren Date: Tue, 25 Mar 2025 21:13:57 +0800 X-Gmail-Original-Message-ID: X-Gm-Features: AQ5f1JorUn_mZoEMhlL0Xe-AITZgnQPYbvOfeukBw1Vy-vsynC2mh-QB0cq8pe8 Message-ID: Subject: Re: [RFC PATCH V3 00/43] rv64ilp32_abi: Build CONFIG_64BIT kernel-self with ILP32 ABI To: Peter Zijlstra Cc: arnd@arndb.de, gregkh@linuxfoundation.org, torvalds@linux-foundation.org, paul.walmsley@sifive.com, palmer@dabbelt.com, anup@brainfault.org, atishp@atishpatra.org, oleg@redhat.com, kees@kernel.org, tglx@linutronix.de, will@kernel.org, mark.rutland@arm.com, brauner@kernel.org, akpm@linux-foundation.org, rostedt@goodmis.org, edumazet@google.com, unicorn_wang@outlook.com, inochiama@outlook.com, gaohan@iscas.ac.cn, shihua@iscas.ac.cn, jiawei@iscas.ac.cn, wuwei2016@iscas.ac.cn, drew@pdp7.com, prabhakar.mahadev-lad.rj@bp.renesas.com, ctsai390@andestech.com, wefu@redhat.com, kuba@kernel.org, pabeni@redhat.com, josef@toxicpanda.com, dsterba@suse.com, mingo@redhat.com, boqun.feng@gmail.com, xiao.w.wang@intel.com, qingfang.deng@siflower.com.cn, leobras@redhat.com, jszhang@kernel.org, conor.dooley@microchip.com, samuel.holland@sifive.com, yongxuan.wang@sifive.com, luxu.kernel@bytedance.com, david@redhat.com, ruanjinjie@huawei.com, cuiyunhui@bytedance.com, wangkefeng.wang@huawei.com, qiaozhe@iscas.ac.cn, ardb@kernel.org, ast@kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-mm@kvack.org, linux-crypto@vger.kernel.org, bpf@vger.kernel.org, linux-input@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-serial@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, maple-tree@lists.infradead.org, linux-trace-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-atm-general@lists.sourceforge.net, linux-btrfs@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, linux-nfs@vger.kernel.org, linux-sctp@vger.kernel.org, linux-usb@vger.kernel.org, linux-media@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 53EEBC0006 X-Rspamd-Server: rspam05 X-Rspam-User: X-Stat-Signature: skjhmfsf65q1pjgdaiwwywim8swcgf4p X-HE-Tag: 1742908452-810578 X-HE-Meta: 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 qbr4ErFw RZLUNSQm1lZxRs0IsYVH78mdfVJTFsqAzRJHCrWENvCn5B5mlzSlO8dYq5k4MD0UMM8h8BTd5QRDrt6zOXBf7+GSBPJ5SURzr9/4YBNSGhdVxzE1aQnToRCAfD10u0EFdcNan3Yh++phPTN5CQJTZYhSUjFNJaG07zpBDnm2Fy58SjZ2ju+9EaVRTbnTuXb1ICrzA2716gdTrLsaCGW0OWikKSxbHiKCnjazPzhNqUv1Zn04Om0EiLsWfJvXiwWZiFMMyU0zFf+7g9I6gkrrY7ji8eQhs7JmgKjD8ea3BxvkQZYcMzjbZRPlJvZq+XP7c/KsVK1EwqBRi6IjKfxkRVT9Iju5JJ7J6XxTrmdEUPVfEXQTH7OUkIQKYaC4yCnX5p1gsssQBUPrYcVIdgWfjSaRbR+blL0tUL0PqOgsjt712050vD7W3GhhT543rjbS7M/4XRFeF93DfYPc+AjaeyOtrqOrhszYy374w/SXhVdSW0HA= 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: On Tue, Mar 25, 2025 at 8:27=E2=80=AFPM Peter Zijlstra wrote: > > On Tue, Mar 25, 2025 at 08:15:41AM -0400, guoren@kernel.org wrote: > > From: "Guo Ren (Alibaba DAMO Academy)" > > > > Since 2001, the CONFIG_64BIT kernel has been built with the LP64 ABI, > > but this patchset allows the CONFIG_64BIT kernel to use an ILP32 ABI > > I'm thinking you're going to be finding a metric ton of assumptions > about 'unsigned long' being 64bit when 64BIT=3Dy throughout the kernel. Less than you imagined. Most code is compatible with ILP32 ABI due to the CONFIG_32BIT. In my practice, it's deemed acceptable. > > I know of a couple of places where 64BIT will result in different math > such that a 32bit 'unsigned long' will trivially overflow. I would be grateful if you could share some with me. > > Please, don't do this. This adds a significant maintenance burden on all > of us. The 64ILP32 ABI would bear the maintenance burden, not traditional 64-bit or 32-bit ABIs. The patch set won't impact other CONFIG_64BIT or CONFIG_32BIT. Numerous RV64 chips require the RV64ILP32 ABI to reduce the memory and cache footprint; we will bear the burden. The core code maintainers would receive patches that would make them use BITS_PER_LONG and CONFIG_64BIT more accurately. --=20 Best Regards Guo Ren