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 X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3AA98C433F5 for ; Fri, 24 Sep 2021 11:36:58 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 05E0660F3A for ; Fri, 24 Sep 2021 11:36:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 05E0660F3A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=D5Cyxj6y763hbXz/BhXn9YKCvG8pqRmLqBQFNRnh7W4=; b=EdMNYr3+NNzDX/ 04eIZcAGjmpDU8XU1kHQyWxlYpJ3Pw8cThz/kxYQ4/gEx/EzS6lhFgI1fceOnFxImaYUglWL6wfz3 xrIbEAwyyVeImzzfVN1FKSPAAt06X3KMoGObYsyhsVLD3tVzKKmX9tIeUCsxGFXvkKZrqkhxqhdn+ hgYONYa69bIVP2UhhdGtwgilqkZOGakD6jXrdR8g1wnQoYnLA6RHD4UO3MQoCO/w7323RNQCkFG/o G3TbaPqk/Ed1Otb/g1uinY8BtavBFOpDq7WzmbNjARdymCIODHmqgR5BS1jWoNONhPbQZTn6UiYca E0ROZOLZ7wvEzQa1ULkA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mTjU0-00EBIR-VT; Fri, 24 Sep 2021 11:35:13 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mTjTx-00EBHC-2s for linux-arm-kernel@lists.infradead.org; Fri, 24 Sep 2021 11:35:10 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 92BF561241; Fri, 24 Sep 2021 11:35:07 +0000 (UTC) Date: Fri, 24 Sep 2021 12:35:04 +0100 From: Catalin Marinas To: Peter Collingbourne Cc: Vincenzo Frascino , Will Deacon , Andrey Konovalov , Evgenii Stepanov , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4] arm64: kasan: mte: move GCR_EL1 switch to task switch when KASAN disabled Message-ID: References: <20210924010655.2886918-1-pcc@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210924010655.2886918-1-pcc@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210924_043509_167313_3E03A4F1 X-CRM114-Status: GOOD ( 10.13 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Sep 23, 2021 at 06:06:55PM -0700, Peter Collingbourne wrote: > It is not necessary to write to GCR_EL1 on every kernel entry and > exit when HW tag-based KASAN is disabled because the kernel will not > execute any IRG instructions in that mode. Since accessing GCR_EL1 > can be expensive on some microarchitectures, avoid doing so by moving > the access to task switch when HW tag-based KASAN is disabled. > > Signed-off-by: Peter Collingbourne > Acked-by: Andrey Konovalov > Link: https://linux-review.googlesource.com/id/I78e90d60612a94c24344526f476ac4ff216e10d2 Reviewed-by: Catalin Marinas _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel