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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1B9C3C982D2 for ; Thu, 17 Sep 2026 18:13:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 143746B0096; Thu, 17 Sep 2026 14:13:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 11B386B0098; Thu, 17 Sep 2026 14:13:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 058266B0099; Thu, 17 Sep 2026 14:13:33 -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 D57216B0096 for ; Thu, 17 Sep 2026 14:13:32 -0400 (EDT) Received: from smtpin16.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 06DEE120454 for ; Thu, 17 Sep 2026 18:13:32 +0000 (UTC) X-FDA: 85224051864.16.E5F8B5D Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf19.hostedemail.com (Postfix) with ESMTP id 2B8801A000F for ; Thu, 17 Sep 2026 18:13:30 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=aYA7qe3T; spf=pass (imf19.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789668810; b=a5X3awK7RvBh9irsTkfW6/JBH1xjfdUDZio3lSEPvfje+rFUG5/SuFPNY2R57CtBrikuyO I0LlkzB7z5fOUX1A+aYxkqsijntC2/5UO3mZV1occVi8yZXe0UEG914KKlsUvSq5PNtY2g 4u7qgSx5Ap8PpxdkjHhG71NGoaBK5dw= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=aYA7qe3T; spf=pass (imf19.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789668810; 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=QAr23lhx8wGsXT6yVi+oXiSZp/vetZhFYtO/kqi1324=; b=nfeUxg+TXFT8SR+degDzBo8XiBDzeLGcP+8ORHn3tpEVt4Wb3m55Igeh6S4XLuKvSZusRn 7XXl5m8n1sEbgswCj8KVLSvcZvLVKbXjsIN3XuI2q96scCLX9i4qkulperxpIH59F/BnpN Idi544xLRPS58EE36FsRdcFqoiR6xlQ= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AB24D1F91; Thu, 17 Sep 2026 11:13:25 -0700 (PDT) Received: from [10.57.7.135] (unknown [10.57.7.135]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D69F63F86F; Thu, 17 Sep 2026 11:13:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789668809; bh=QAr23lhx8wGsXT6yVi+oXiSZp/vetZhFYtO/kqi1324=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=aYA7qe3TJmI5eXy7zuCDNvjC424BNkx9TqHpOMlyNEkNvwpgRn5lsECsH9o7hC0RG 5jIxS0q8ZHaQOP2dIWzY39HZw+w/QDzFAaZ5etprv7QyoTOG2UkZgMUVBbr0E0ztmK wHMiHRGdA5HaFJ3DgcETN41w6QqxGhhxvHgViRbE= Message-ID: <685fa7b1-af6d-4dc0-8764-5bcb169b39ae@arm.com> Date: Thu, 17 Sep 2026 20:13:19 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 5/6] mm/execmem: use VM_FLUSH_RESET_PERMS for ROX cache allocations To: "Mike Rapoport (Microsoft)" , Andrew Morton Cc: =?UTF-8?Q?Adrian_Barna=C5=9B?= , Albert Ou , Alexander Gordeev , Alexandre Ghiti , Andy Lutomirski , Borislav Petkov , Brendan Jackman , Catalin Marinas , Christian Borntraeger , Dave Hansen , David Hildenbrand , Gerald Schaefer , Heiko Carstens , Huacai Chen , Ingo Molnar , Len Brown , Palmer Dabbelt , Paul Walmsley , Pavel Machek , Peter Zijlstra , "H. Peter Anvin" , "Rafael J. Wysocki" , Ryan Roberts , Sven Schnelle , Thomas Gleixner , Uladzislau Rezki , Vasily Gorbik , WANG Xuerui , Will Deacon , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, loongarch@lists.linux.dev References: <20260903-execmem-set-vm-perms-v0-2-v3-0-949b64a9f755@kernel.org> <20260903-execmem-set-vm-perms-v0-2-v3-5-949b64a9f755@kernel.org> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: <20260903-execmem-set-vm-perms-v0-2-v3-5-949b64a9f755@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 2B8801A000F X-Rspam-User: X-Stat-Signature: grtnsrpym617jqrhrc4tfaaex334qn4b X-HE-Tag: 1789668810-248290 X-HE-Meta: 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 xdMwgV9X ulMg9c0LuriqyEPmAjVYLSmlNkas/G5W+CQ9DBK1Kf6Mf9yibXQq3BjBsnozyl1VJ/TBeBNQL//hVirv4zDGjWf2kSPghoNc12T0sZP8GJNH38xG43zyD2a9styubhccdzr6sijIb4TLqEA40iqWSjQIrtKRz2nGiQmX+FmLcmbrdldZfeUsBlwsQqTaxRj1iYDbQoTct0R7yuqv85yHaBDPD1WWrFI65vFNLJ7SmhntbXJEWty4GoZIU68i7LZXz8jOXc70B1IyI2gLj7IKLT2yzYhAKzQKxgVj35RLTnqjJ0E908wkxgUNp1j7EVVFTwNQ21WsoaSWSwHI7FeyRQiPWRzpbMv+BiE+LTRA9R0bwYS0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 03/09/2026 11:28, Mike Rapoport (Microsoft) wrote: > Initially execmem completely removed direct map alias for the memory > allocated for the ROX cache in PMD_SIZE chunks. When that memory was > freed, its direct map was restored also in PMD_SIZE chunks to avoid > fragmentation of the direct map caused by vmalloc::vm_reset_perms(). > > This required execmem to implement the wrappers for set_direct_map APIs for > proper sequencing of removal and restoration of the direct map aliases. > > Since then x86's CPA gained support for collapsing the direct map page > tables for ROX pages and execmem switched from removing ROX caches from the > direct map to making them ROX there, so execmem only needs to update direct > map alias permissions when freeing the ROX cache memory. > > vmalloc already handles those updates for areas with VM_FLUSH_RESET_PERMS > set and vmalloc::vm_reset_perms() does not force split of the direct map > for PMD_SIZE chunks. > > Set the area permissions with set_vm_flush_reset_perms() when populating > the execmem cache just before flipping the area to ROX. > > This way freeing an allocated area on an error path won't incur two > updates of the direct map alias of that area and TLB flushing in > vm_reset_perms(). > > Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Kevin Brodsky