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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E59AFC47DD9 for ; Wed, 27 Mar 2024 16:24:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Subject:Cc:To:From:Date:References: In-Reply-To:Message-Id:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ceD2wek7KzkYp5jtKdlPpwZ9wR4AXri/7ayAklDhrvQ=; b=D0MU2cSEbmHCM3 hvh4qmnlluTPB15KV9rrky1SRBrbSNmWgzst16llIdThWtHpt4L7engtZa657eRV7PwVpmlYSCtGr uv52ek6uzh1Cs/lXRf3jZ5EncebeJhpc2E0romQM93t4k7HgDdOxXQxSpW7P6omAR1nFLdsF6KHkI ueIKy4tfwRekOn9OVpwxPvQxKhK82z93jXMhZoMRnzRKEgPXEIwsaurmjFuNTvQa0RLEHsT9kBWDM ewRznrVnbZl2KyFv/qM38NVI44j334/TsTAtUnSNgdqLFhPOk0A1/iheEV/kJ6QrCsirXCWU1P5kg hlIgS8z7j50dFoEGWYZw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rpW4x-0000000A4Uh-41wU; Wed, 27 Mar 2024 16:24:43 +0000 Received: from fhigh7-smtp.messagingengine.com ([103.168.172.158]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rpW4u-0000000A4Ts-2wPk for linux-riscv@lists.infradead.org; Wed, 27 Mar 2024 16:24:42 +0000 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailfhigh.nyi.internal (Postfix) with ESMTP id 35B2E1140164; Wed, 27 Mar 2024 12:24:38 -0400 (EDT) Received: from imap51 ([10.202.2.101]) by compute5.internal (MEProxy); Wed, 27 Mar 2024 12:24:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:subject :subject:to:to; s=fm1; t=1711556678; x=1711643078; bh=fdt0R9lStJ 8mfdJYKIs6B7xZtVK2mxT5Rl1pe5p+Hik=; b=PXVUiX/pq9Y35PYlE8mKVAEzBy tGBvQVWMdfylmG0RXDdVIg8YzbhSv9deUbwUFgCqUXeSU+q73W08XcJwgKaLXXe0 MbsngyksrPKUGVyJ3J3sXhRRwfoSkH+6aBFRMOwMEKEqA0Cp+3fn7ljxgLvmlJQ0 m/AYZ7Lbyk9EmvoUbahZLB/UdXtIngo158eXbIg8KvL5O5qj66x8IaaFJLZqvBGr as5uAvF51xhnoFNxUbOWPooSvIsSDXphnj9Rmm/wUF8BsdNn6IsDMARMW9LW7jHw w8IohPhRjqZzTxrcTUCFR2wsEIehTF9tN0tN2j6E+B6K2LQVfkatdW9hnYUA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; t=1711556678; x=1711643078; bh=fdt0R9lStJ8mfdJYKIs6B7xZtVK2 mxT5Rl1pe5p+Hik=; b=Q4PamvyQ3XQ2dFVVQGAnrcx0rXFTTHfaUrQW9QMaL/r/ egqAD4IvvIz0S+tztS4FzCXpaGuoGzl5qswSXlZ7RGkVDrpvIKMEej49rRm02JWi psZGkg0nLQ21xsraQ/fjdWPQPOL8ZHAhBtZt4zuADrsYfQU/Cob45NzzbE3gmOFQ tLMzgIjoF2jlRMVpvPXXHZKi8zwSlFyvVkH1nSU1xe0hR9MveqdPNfgj5AtYN4rd V4+1JrCd/LSASPzBuALH5Phfa9eE/AYJFmUh8qkKMtCGiKVQ1VPkpoPDVk+IWoxc kNWfvd22+OKD1ZfKUwDK8OznPdM+Yc0ZONgavFFceg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvledrudduiedgieegucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehr nhguuceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrth htvghrnhepffehueegteeihfegtefhjefgtdeugfegjeelheejueethfefgeeghfektdek teffnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprg hrnhgusegrrhhnuggsrdguvg X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 92528B6008D; Wed, 27 Mar 2024 12:24:37 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.11.0-alpha0-328-gc998c829b7-fm-20240325.002-gc998c829 MIME-Version: 1.0 Message-Id: <4d2fa4cd-4e21-4504-b29b-cfabe90693aa@app.fastmail.com> In-Reply-To: <20240327143858.711792-3-samuel.holland@sifive.com> References: <20240327143858.711792-1-samuel.holland@sifive.com> <20240327143858.711792-3-samuel.holland@sifive.com> Date: Wed, 27 Mar 2024 17:24:06 +0100 From: "Arnd Bergmann" To: "Samuel Holland" , "Palmer Dabbelt" , linux-riscv@lists.infradead.org Cc: "Mark Rutland" , "David Laight" , "Alexandre Ghiti" Subject: Re: [PATCH v2 2/2] riscv: Define TASK_SIZE_MAX for __access_ok() X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240327_092440_824974_2F5B456D X-CRM114-Status: GOOD ( 11.58 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Wed, Mar 27, 2024, at 15:38, Samuel Holland wrote: > TASK_SIZE_MAX should be set to a constant value, at least the largest > valid userspace address under any runtime configuration. This optimizes > the check in __access_ok(), which no longer needs to compute the runtime > value of TASK_SIZE. The check does not need to be exact, as long as it > accepts all valid userspace addresses and rejects all valid kernel > addresses; well-behaved programs will never fail the access_ok() check. > > For RISC-V, which requires all virtual addresses to be sign extended, > the optimal choice is LONG_MAX because it simplifies the limit > comparison to a sign bit test. > > This removes about half of the references to pgtable_l[45]_enabled. > > Signed-off-by: Samuel Holland Reviewed-by: Arnd Bergmann _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv