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 E5F1AC5B543 for ; Tue, 10 Jun 2025 12:25:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=1cJe902L5Fmu1I390q3hKJDnbyZton5mKNCwWQ2f1zs=; b=0BhiWUM0yB0buD7rRTeUzLvXt8 NMENBDVWuWdbV2kXIQehSuMQQuFMW6vztlRBJ0YScQbIddpjbx2urB0KW9yi+tnT+6Jbz3AiT/nXn 1qpEeIuKSHeHc2VUWmpshZd3Yvn7I4DeEC5d/Bt8FtREtcqRoABJVHNMbu7BkjVUYkY5bE626eBtC j3yTILhqjWNn+81znYCKboh7ha+LLo2POBI3mUkvVgAye0beHR1U0Q8CDIo/i2Sfs+PzR4BxfrJiC 9ANc/BRZS3CrDezC3oG7lrYNJA23hTulIh+rv+i7FE32MeUdE9HCZIR8j8xq0pDMIZM9T9xRr4Bwc vIUZgQqg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uOy2b-00000006lQW-3Yr8; Tue, 10 Jun 2025 12:25:21 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uOxOu-00000006gNB-3PqV for linux-arm-kernel@bombadil.infradead.org; Tue, 10 Jun 2025 11:44:20 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:In-Reply-To:References; bh=1cJe902L5Fmu1I390q3hKJDnbyZton5mKNCwWQ2f1zs=; b=ByDqLY90WRl+veD0luxyzO8KeD 5NbNZaS+YerxM7S9WJwYQ+kXvKZgZgnprFKGYl/u7ezaprb5XxWwgn/xiKVaEFhSrhIbCxo/8n7Qp pYMi5z/hNsacN3fX2NSPX6NcQShCvcjaXCRod8swdqXGEqOy5adblkGq1iY7tnWf95xjhpSQXcc0e 4aLn04z5+3x1IcQ3GSTL9QCmZ6TkyMKwRdnjG2Gt79IzPXesREdKoI/jt3t1K8DX0JUjGtTOthELW 4ttH8mKlZ6hufp8lgiNDIQykqxJ2Gvxcj9ijifLOX0U1gc/A6/CsQlsdmt0zajxIMTFwNdhLvmd8O nIikkcNQ==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uOxOs-00000001mub-0a0x for linux-arm-kernel@lists.infradead.org; Tue, 10 Jun 2025 11:44:20 +0000 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 A987C169C; Tue, 10 Jun 2025 04:43:55 -0700 (PDT) Received: from MacBook-Pro.blr.arm.com (MacBook-Pro.blr.arm.com [10.164.18.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 3B5713F59E; Tue, 10 Jun 2025 04:44:08 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org, david@redhat.com, catalin.marinas@arm.com, will@kernel.org Cc: lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, suzuki.poulose@arm.com, steven.price@arm.com, gshan@redhat.com, linux-arm-kernel@lists.infradead.org, yang@os.amperecomputing.com, ryan.roberts@arm.com, anshuman.khandual@arm.com, Dev Jain Subject: [PATCH v2 0/2] Enable permission change on arm64 kernel block mappings Date: Tue, 10 Jun 2025 17:13:59 +0530 Message-Id: <20250610114401.7097-1-dev.jain@arm.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250610_124418_392997_86178821 X-CRM114-Status: GOOD ( 10.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This series paves the path to enable huge mappings in vmalloc space and linear map space by default on arm64. For this we must ensure that we can handle any permission games on the kernel (init_mm) pagetable. Currently, __change_memory_common() uses apply_to_page_range() which does not support changing permissions for leaf mappings. We attempt to move away from this by using walk_page_range_novma(), similar to what riscv does right now; however, it is the responsibility of the caller to ensure that we do not pass a range, or split the range covering a partial leaf mapping. This series is tied with Yang Shi's attempt [1] at using huge mappings in the linear mapping in case the system supports BBML2, in which case we will be able to split the linear mapping if needed without break-before-make. Thus, Yang's series, IIUC, will be one such user of my series; suppose we are changing permissions on a range of the linear map backed by PMD-hugepages, then the sequence of operations should look like the following: split_range(start) split_range(end); ___change_memory_common(start, end); However, this series can be used independently of Yang's; since currently permission games are being played only on pte mappings (due to apply_to_page_range not supporting otherwise), this series provides the mechanism for enabling huge mappings for various kernel mappings like linear map and vmalloc. [1] https://lore.kernel.org/all/20250304222018.615808-1-yang@os.amperecomputing.com/ v1->v2: - Squash patch 2 and 3 - Add comment describing the responsibility of the caller to ensure no partial overlap with block mapping - Add comments and return -EINVAL at relevant places to document the usage of PGWALK_NOLOCK (Lorenzo) - Nest walk_kernel_page_table_range() with lazy_mmu calls, instead of doing so only per PTE level, fix bug in the PTE callback, introduce callbacks for all pagetable levels, use ptdesc_t instead of unsigned long, introduce ___change_memory_common and use them for direct map permission change functions (Ryan) v1: https://lore.kernel.org/all/20250530090407.19237-1-dev.jain@arm.com/ Dev Jain (2): mm: Allow lockless kernel pagetable walking arm64: pageattr: Use walk_page_range_novma() to change memory permissions arch/arm64/mm/pageattr.c | 158 +++++++++++++++++++++++++++++++-------- include/linux/pagewalk.h | 7 ++ mm/pagewalk.c | 23 ++++-- 3 files changed, 151 insertions(+), 37 deletions(-) -- 2.30.2