From patchwork Thu Jan 25 16:42:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 13531482 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 82FC5C47258 for ; Thu, 25 Jan 2024 17:49:56 +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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=sC8JmadykEqQNsicIIpK9lpCMfCYt+jKC1VtRtbNoF0=; b=qfmy4uf7YZvihC ddxJF5hcOLsv4haAoj7gELxD7Dkh/77+i6+UnIRHaDRJs/VCOuuFV9UKo+naEebWsJSj6hp4rXcta vj5jfkYWqxl7uu4PIQGXRRulv4KxvMfKioNKOrWw7VEutE3lm2HwMWxcw45IF5x1nRo9v5kv1Y6Uj L+vwDYVqTxLt/P7J+owKAp3KeFHqSgcSnzlTVIV6L6Xj73NM3S6qt6kiqV4fYy9efGKJuz+wCUwyn XIkFUisQ7qe0gBgq6DxqB9Ac1TIaabX5GngNc96UVTFgPjDG4MdwEbRXLDxXKpMY6ceo6W4edB2D5 XQds+Dy1HjLWy/BXPjVQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rT3rG-00000001DDZ-3MYh; Thu, 25 Jan 2024 17:49:46 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rT2qQ-00000000tDE-3Ett for linux-arm-kernel@lists.infradead.org; Thu, 25 Jan 2024 16:44:52 +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 E894C1688; Thu, 25 Jan 2024 08:45:32 -0800 (PST) Received: from e121798.cable.virginm.net (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 03CA73F5A1; Thu, 25 Jan 2024 08:44:42 -0800 (PST) From: Alexandru Elisei To: catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com Cc: pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, david@redhat.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH RFC v3 21/35] arm64: mte: Disable dynamic tag storage management if HW KASAN is enabled Date: Thu, 25 Jan 2024 16:42:42 +0000 Message-Id: <20240125164256.4147-22-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240125164256.4147-1-alexandru.elisei@arm.com> References: <20240125164256.4147-1-alexandru.elisei@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240125_084450_890922_9342D8EB X-CRM114-Status: GOOD ( 10.48 ) 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 To be able to reserve the tag storage associated with a tagged page requires that the tag storage can be migrated, if it's in use for data. The kernel allocates pages in non-preemptible contexts, which makes migration impossible. The only user of tagged pages in the kernel is HW KASAN, so don't use tag storage pages if HW KASAN is enabled. Signed-off-by: Alexandru Elisei --- Changes since rfc v2: * Expanded commit message (David Hildenbrand) arch/arm64/kernel/mte_tag_storage.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/arm64/kernel/mte_tag_storage.c b/arch/arm64/kernel/mte_tag_storage.c index 90b157132efa..9a1a8a45171e 100644 --- a/arch/arm64/kernel/mte_tag_storage.c +++ b/arch/arm64/kernel/mte_tag_storage.c @@ -256,6 +256,16 @@ void __init mte_init_tag_storage(void) goto out_disabled; } + /* + * The kernel allocates memory in non-preemptible contexts, which makes + * migration impossible when reserving the associated tag storage. The + * only in-kernel user of tagged pages is HW KASAN. + */ + if (kasan_hw_tags_enabled()) { + pr_info("KASAN HW tags incompatible with MTE tag storage management"); + goto out_disabled; + } + /* * Check that tag storage is addressable by the kernel. * cma_init_reserved_mem(), unlike cma_declare_contiguous_nid(), doesn't