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[2620:137:e000::1:20]) by mx.google.com with ESMTP id w2-20020a170902ca0200b001b69de1eaecsi892442pld.489.2023.06.23.01.13.38; Fri, 23 Jun 2023 01:13:50 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230245AbjFWH6M (ORCPT + 99 others); Fri, 23 Jun 2023 03:58:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230163AbjFWH6K (ORCPT ); Fri, 23 Jun 2023 03:58:10 -0400 Received: from lgeamrelo11.lge.com (lgeamrelo11.lge.com [156.147.23.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1B9381BCC for ; Fri, 23 Jun 2023 00:58:07 -0700 (PDT) Received: from unknown (HELO lgeamrelo01.lge.com) (156.147.1.125) by 156.147.23.51 with ESMTP; 23 Jun 2023 16:58:05 +0900 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: chanho.min@lge.com Received: from unknown (HELO localhost.localdomain) (10.178.31.96) by 156.147.1.125 with ESMTP; 23 Jun 2023 16:58:05 +0900 X-Original-SENDERIP: 10.178.31.96 X-Original-MAILFROM: chanho.min@lge.com From: Chanho Min To: andreyknvl@gmail.com Cc: chanho.min@lge.com, dvyukov@google.com, elver@google.com, glider@google.com, gunho.lee@lge.com, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ryabinin.a.a@gmail.com, vincenzo.frascino@arm.com Subject: [PATCH v2] kasan: fix mention for KASAN_HW_TAGS Date: Fri, 23 Jun 2023 16:58:05 +0900 Message-Id: <20230623075805.1630-1-chanho.min@lge.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SORTED_RECIPS,SPF_HELO_NONE, SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1769126114589219327?= X-GMAIL-MSGID: =?utf-8?q?1769480420827444225?= This patch fixes description of the KASAN_HW_TAGS's memory consumption. KASAN_HW_TAGS are dependent on the HW implementation and are not reserved from system memory like shadow memory. Suggested-by: Andrey Konovalov Signed-off-by: Chanho Min Reviewed-by: Andrey Konovalov --- lib/Kconfig.kasan | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index fdca89c05745..f8f9e12510b7 100644 --- a/lib/Kconfig.kasan +++ b/lib/Kconfig.kasan @@ -124,7 +124,8 @@ config KASAN_HW_TAGS Supported only on arm64 CPUs starting from ARMv8.5 and relies on Memory Tagging Extension and Top Byte Ignore. - Consumes about 1/32nd of available memory. + Does not consume memory by itself but relies on the 1/32nd of + available memory being reserved by the firmware when MTE is enabled. May potentially introduce problems related to pointer casting and comparison, as it embeds a tag into the top byte of each pointer.