From patchwork Sun Nov 19 16:57:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 13460573 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7C8C1172D; Sun, 19 Nov 2023 08:58:53 -0800 (PST) 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 8E171DA7; Sun, 19 Nov 2023 08:59:39 -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 5A3EA3F6C4; Sun, 19 Nov 2023 08:58:48 -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 v2 14/27] arm64: mte: Disable dynamic tag storage management if HW KASAN is enabled Date: Sun, 19 Nov 2023 16:57:08 +0000 Message-Id: <20231119165721.9849-15-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231119165721.9849-1-alexandru.elisei@arm.com> References: <20231119165721.9849-1-alexandru.elisei@arm.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To be able to reserve the tag storage associated with a page requires that the tag storage page can be migrated. When HW KASAN is enabled, the kernel allocates pages, which are now tagged, in non-preemptible contexts, which can make reserving the associate tag storage impossible. Keep the tag storage pages reserved if HW KASAN is enabled. Signed-off-by: Alexandru Elisei --- arch/arm64/kernel/mte_tag_storage.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/kernel/mte_tag_storage.c b/arch/arm64/kernel/mte_tag_storage.c index 427f4f1909f3..8b9bedf7575d 100644 --- a/arch/arm64/kernel/mte_tag_storage.c +++ b/arch/arm64/kernel/mte_tag_storage.c @@ -308,6 +308,19 @@ static int __init mte_tag_storage_activate_regions(void) goto out_disabled; } + /* + * The kernel allocates memory in non-preemptible contexts, which makes + * migration impossible when reserving the associated tag storage. + * + * The check is safe to make because KASAN HW tags are enabled before + * the rest of the init functions are called, in smp_prepare_boot_cpu(). + */ + if (kasan_hw_tags_enabled()) { + pr_info("KASAN HW tags incompatible with MTE tag storage management"); + ret = 0; + goto out_disabled; + } + for (i = 0; i < num_tag_regions; i++) { tag_range = &tag_regions[i].tag_range; for (pfn = tag_range->start; pfn <= tag_range->end; pfn += pageblock_nr_pages)