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 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 2A277C433F5 for ; Fri, 28 Jan 2022 16:58:20 +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:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:Subject:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=t4AeOcmLn5oVivr2D9ls6xIF7QbK/y0NXsggzF4dzyA=; b=B052IvHec0BMCP2JjImwi9Zyej Vdvto1W/pKX2CIBTm0PkefjiDh71iAHSTRK3celOL8B2IgQ0opmZ9XENv2ZoiBCHAF5zyc/2UO2Pv VMwdpnAk7kLJQ6scP1mDc2mUHOrcDSbE9Z0fTDeVWsRYFMZmNXnrp17JoTSNXvRDOqOGR5FdrH/4Z FExGpxwtgDBLk4XO5TCwLK441MfA9AAwB7FRZiNrbC+8sI3poGUfGOUDe8DOgziE/BMMNhLdwvI+5 PD6PemQPXk1BviDgARWUU07dJZOd+DX8Q/qR9Bvt6kB4HVS4zGwvkBkCQrZMPb8INGP9Zci8uQgm9 jAQJQ/dQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nDUYi-0036Q9-4q; Fri, 28 Jan 2022 16:57:12 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nDUYd-0036P0-IF for linux-arm-kernel@lists.infradead.org; Fri, 28 Jan 2022 16:57:08 +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 94828113E; Fri, 28 Jan 2022 08:57:06 -0800 (PST) Received: from [192.168.4.21] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 56A4A3F793; Fri, 28 Jan 2022 08:57:05 -0800 (PST) Subject: Re: [PATCH v1 2/4] arm64/mte: Add a little bit of documentation for mte_update_sctlr_user() To: Mark Brown , Catalin Marinas , Will Deacon Cc: Joey Gouly , Branislav Rankov , linux-arm-kernel@lists.infradead.org References: <20220127195712.748150-1-broonie@kernel.org> <20220127195712.748150-3-broonie@kernel.org> From: Vincenzo Frascino Message-ID: Date: Fri, 28 Jan 2022 16:57:12 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20220127195712.748150-3-broonie@kernel.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220128_085707_708567_20C53FC2 X-CRM114-Status: GOOD ( 21.62 ) 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 1/27/22 7:57 PM, Mark Brown wrote: > The code isn't that obscure but it probably won't hurt to have a little > bit more documentation for anyone trying to find out where everything > actually takes effect. > > Signed-off-by: Mark Brown Reviewed-by: Vincenzo Frascino > --- > arch/arm64/kernel/mte.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c > index f418ebc65f95..fa4001fee12a 100644 > --- a/arch/arm64/kernel/mte.c > +++ b/arch/arm64/kernel/mte.c > @@ -186,6 +186,11 @@ void mte_check_tfsr_el1(void) > } > #endif > > +/* > + * This is where we actually resolve the system and process MTE mode > + * configuration into an actual value in SCTLR_EL1 that affects > + * userspace. > + */ > static void mte_update_sctlr_user(struct task_struct *task) > { > /* > @@ -199,8 +204,17 @@ static void mte_update_sctlr_user(struct task_struct *task) > unsigned long pref, resolved_mte_tcf; > > pref = __this_cpu_read(mte_tcf_preferred); > + /* > + * If there is no overlap between the system preferred and > + * program requested values go with what was requested. > + */ > resolved_mte_tcf = (mte_ctrl & pref) ? pref : mte_ctrl; > sctlr &= ~SCTLR_EL1_TCF0_MASK; > + /* > + * Pick an actual setting. The order in which we check for > + * set bits and map into register values determines our > + * default order. > + */ > if (resolved_mte_tcf & MTE_CTRL_TCF_ASYNC) > sctlr |= SCTLR_EL1_TCF0_ASYNC; > else if (resolved_mte_tcf & MTE_CTRL_TCF_SYNC) > -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel