From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: [PATCH v3 06/23] arm64: mte: Tags-aware clear_page() implementation Date: Tue, 21 Apr 2020 15:25:46 +0100 Message-ID: <20200421142603.3894-7-catalin.marinas@arm.com> References: <20200421142603.3894-1-catalin.marinas@arm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Received: from foss.arm.com ([217.140.110.172]:35920 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728645AbgDUO0W (ORCPT ); Tue, 21 Apr 2020 10:26:22 -0400 In-Reply-To: <20200421142603.3894-1-catalin.marinas@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon , Vincenzo Frascino , Szabolcs Nagy , Richard Earnshaw , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , linux-mm@kvack.org, linux-arch@vger.kernel.org From: Vincenzo Frascino When the Memory Tagging Extension is enabled, the tags need to be set to zero a page is cleared as they are visible to the user. Introduce an MTE-aware clear_page() which clears the tags in addition to data. Signed-off-by: Vincenzo Frascino Co-developed-by: Catalin Marinas Signed-off-by: Catalin Marinas Cc: Will Deacon --- arch/arm64/lib/clear_page.S | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm64/lib/clear_page.S b/arch/arm64/lib/clear_page.S index 073acbf02a7c..9f85a4cf9568 100644 --- a/arch/arm64/lib/clear_page.S +++ b/arch/arm64/lib/clear_page.S @@ -5,7 +5,9 @@ #include #include +#include #include +#include #include /* @@ -19,8 +21,9 @@ SYM_FUNC_START(clear_page) and w1, w1, #0xf mov x2, #4 lsl x1, x2, x1 - -1: dc zva, x0 +1: +alternative_insn "dc zva, x0", "stzgm xzr, [x0]", \ + ARM64_MTE, IS_ENABLED(CONFIG_ARM64_MTE), 1 add x0, x0, x1 tst x0, #(PAGE_SIZE - 1) b.ne 1b