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 5BFFCC83F07 for ; Mon, 7 Jul 2025 11:50:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DE0F08D0003; Mon, 7 Jul 2025 07:50:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DB8D38D0002; Mon, 7 Jul 2025 07:50:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CF66C8D0003; Mon, 7 Jul 2025 07:50:08 -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 BC2898D0002 for ; Mon, 7 Jul 2025 07:50:08 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 42923B9B9C for ; Mon, 7 Jul 2025 11:50:08 +0000 (UTC) X-FDA: 83637300096.03.FDB4008 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf26.hostedemail.com (Postfix) with ESMTP id 8198214000E for ; Mon, 7 Jul 2025 11:50:06 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=AQnc7yKN; spf=pass (imf26.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@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=1751889006; 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=lb06dMDL2yXZ/VPDdE+aXdf6yrjhm0hIXg63yvABdIg=; b=1AeeyybpmG1cumHpQa0cW606howlUtGbSjyetLOtvZKYmBhj7o16E8cqX2dodkApbtqzNH tDw6NALQjrfBE0pP19tMqrGod4qtvj7d+KscAhPquEo/kgYJrFTK00r0z7y1VpWCXgjX33 qceboo4R2kUl+SbuNeUnXuEzyAxu3sQ= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=AQnc7yKN; spf=pass (imf26.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1751889006; a=rsa-sha256; cv=none; b=mBCzUMAkn2DhS4Jg4yzQxWPp3M6f6vhfoEuHZ5SBdg1W7Or7ereeN0rTRU3j3j8byPgYNA dbn1YYPl4sFteDQcocGRD1x610kPw4YpnSMOYb7JSMyQpx41jmZZZqjalGsFXRYINfswqS idUFVJTkkOmujDhbLxbTwwK0Lk89qf8= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 1877443D2B; Mon, 7 Jul 2025 11:50:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 727DEC4CEE3; Mon, 7 Jul 2025 11:49:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751889005; bh=gMlTu9+xpafBOmuhtK1ioviaKSGzsyQjs0ZPKAH3vHE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AQnc7yKNW3i8pmak2bYHKx2Cz85ciohsohKN9pxII2y9lEWftE7WydnybBVfZbIad INSkrf1uXq4CXyCWssKQEyW4K+HeEfwpUu059CUl4epfcb3RFELY+9g4TI5J/iEoyq lGMwEGBfUidqbLh87sxYEXp/waMNBs7XCaeR0yghvuco4KQDF2WUUJlRpNFWYphEhV Vc3DBNvJSS1XcyK7n8TnqH8X0zTcrsnvH3/9mg8H3LeOcaO1Xavw1t9xSzgGQ27jeS FLirz73cArp1zZ9eEA5vf6TRtDA2vz59Muxcjjpd8+OGLRVB/EHazahnfmDhH6n98h aLX0DWT5F92ug== Date: Mon, 7 Jul 2025 14:49:54 +0300 From: Mike Rapoport To: Christophe Leroy Cc: Andrew Morton , Andy Lutomirski , Borislav Petkov , Daniel Gomez , Dave Hansen , Ingo Molnar , Luis Chamberlain , Mark Rutland , Masami Hiramatsu , "H. Peter Anvin" , Peter Zijlstra , Petr Pavlu , Sami Tolvanen , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 1/8] execmem: drop unused execmem_update_copy() Message-ID: References: <20250704134943.3524829-1-rppt@kernel.org> <20250704134943.3524829-2-rppt@kernel.org> <7e52f721-1d8e-4c50-af33-bee3f0d2ac6e@csgroup.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <7e52f721-1d8e-4c50-af33-bee3f0d2ac6e@csgroup.eu> X-Stat-Signature: rkk8shjmxz9j3a3h5f4krqeykx953m6b X-Rspamd-Queue-Id: 8198214000E X-Rspam-User: X-Rspamd-Server: rspam07 X-HE-Tag: 1751889006-661130 X-HE-Meta: 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 jXP5V23B iYLPiolV3N9nCL6jgIZYIFVzAsgw9egluQlOoWcfynJ4/Ct4yDcFSrpE+NBP8Jf5izXZjwR8FAyg+KO/tLNv/kgdcChI2va/bETpQ1R6NK+SwQhDP6JoEFe13RbqD83z68V6H3kY3syk+GxWpagg6TQKecwWvRRdUjtlbAKYd+lrCbTd0QmlH4SlcvKQJVMbNkQ2BnROqMlgZHFgvx7OGKDREzI1qQWtvvoOwPKk5QfjvMG/YHSTIuL+p5WSaFwWJgtLeO2nMvaguGaTJ3KgCArNb3563x7VrcDZx/2fDyFZApr3K86xUuVadGhiyjP14AInMFJ2MVQw8YTBQ+F2WZ1yxlAnpBMs+B9TX 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 Mon, Jul 07, 2025 at 12:10:43PM +0200, Christophe Leroy wrote: > > Le 04/07/2025 à 15:49, Mike Rapoport a écrit : > > From: "Mike Rapoport (Microsoft)" > > > > The execmem_update_copy() that used text poking was required when memory > > allocated from ROX cache was always read-only. Since now its permissions > > can be switched to read-write there is no need in a function that updates > > memory with text poking. > > Erm. Looks like I missed the patch that introduced this change. > > On some variant of powerpc, namely book3s/32, this is not feasible. The only user of EXECMEM_ROX_CACHE for now is x86-64, we can always revisit when powerpc book3s/32 would want to opt in to cache usage. And it seems that [MODULES_VADDR, MODULES_END] is already mapped with "large pages", isn't it? > The granularity for setting the NX (non exec) bit is 256 Mbytes sections. > So the area dedicated to execmem [MODULES_VADDR; MODULES_END[ always have > the NX bit unset. > > You can change any page within this area from ROX to RWX but you can't make > it RW without X. If you want RW without X you must map it in the VMALLOC > area, as VMALLOC area have NX bit always set. So what will happen when one callse set_memory_nx() set_memory_rw() in such areas? > Christophe -- Sincerely yours, Mike.