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 BE632C433EF for ; Thu, 27 Jan 2022 20:07:05 +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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Ksw7Y1D3eLMwj4ZCoAymeutLxrpX07/bmro9XjArkUA=; b=PRm6LPC/frNBsL xGkWztDsSb84XYoFF0kMfgEjP2MfxwlzOUTyLNZPUFNkrIWAz15JsuO0lv1fOboESDbqn6FZDrnZh MvGLByH7zq9Lbjmz0h+91aof68hcch7Gek5cwZzO4elXNsLXkqBRG/qZwLGBYo3+ZwLlLP+iDWKDf 9mUNlBSZ+Hf+W6ByN+Q0AtO55y6ucfiUNgCHZhXwZDUmXx2OXvxj0nrRRgq2gKGPvUlgyNzQBuoUL OouQIaPx5BOAEaYv6Ul9T3wri+PjIgJD+ep2Hue6cYm2M+rKuJo+cEKn4nLqS5sl2/nLkJ0Qz3Cne S7I6LiomGjfFh2gIV3aw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nDB1f-00H23K-AJ; Thu, 27 Jan 2022 20:05:47 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nDB1D-00H1xt-LV for linux-arm-kernel@lists.infradead.org; Thu, 27 Jan 2022 20:05:22 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 36C1761821; Thu, 27 Jan 2022 20:05:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3706EC340E9; Thu, 27 Jan 2022 20:05:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643313918; bh=CaFTRKHk47lD85Hpz3EcpcdinjIjErvX/1dDyKuKuLk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rPelgSDkhaI+ZhtyPZz0hrJBNbqnu7fkJahK4j15fJNVWr8+AHmmZcPi4fGcxv1KP YuWj32lf+ZRMTmCn45dnQyYpB5DcB2Z3L0rKEDPchjSuQV0vV85KhOAQWHpYxBLxqk SnZiRl+jovv4C6xu1KWJIYCCo00URXdf998PGsGZjxCWmmXi3deGixLryIedvdFVOk fgc9JOkPfniLEKUT3Z3hPc/rpCTvGuh2JhYgjBYMZnlCMIQM0oZg9TRJUU2GvR6oNW nhd1wtOWJYhvny6IiXHMR2RFtvVZJ5ab1GoeVj1HA+ocyugwnPGS4N/kz3wxoCspaI BYvEnM/MTwhFA== From: Mark Brown To: Catalin Marinas , Will Deacon Cc: Joey Gouly , Branislav Rankov , linux-arm-kernel@lists.infradead.org, Mark Brown Subject: [PATCH v1 2/4] arm64/mte: Add a little bit of documentation for mte_update_sctlr_user() Date: Thu, 27 Jan 2022 19:57:10 +0000 Message-Id: <20220127195712.748150-3-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220127195712.748150-1-broonie@kernel.org> References: <20220127195712.748150-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1475; h=from:subject; bh=CaFTRKHk47lD85Hpz3EcpcdinjIjErvX/1dDyKuKuLk=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBh8vkVz8KIeVXRvosyV1rfl11GkG2vUKsb25pZcx0N 9MtCjY6JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYfL5FQAKCRAk1otyXVSH0FziB/ 4qyWA29AtJAuusssFKbO5N2FTOdae9wJQc0eJa7YBe8G72MHkoctigPVS/LjVoWn4mYy8NQnUY2sEn 6VEhiIMncpxHz92MphPMa6aJWYhVh5K1mCZ0EMceq6lQT3Oi+LK06ZT/e+Uu5xrfmA208TF8+1hEu6 mPYy3sEdkttD1tENZoVWINCCPuQ0cU3Sij3kisfqux3AcPYbSoai4B/GhVkOsXnjR0XgCcr/FjBo1F QjcDdvEEV9L0IEGvwSPcUC3WcuqEYtIeJp1ys52TLdkaaBVm6j6fLWbo5iqMsVpj/8dTqKfj+yShJx DG3Lz8G7Rsn90zCDvVXj0WVnse3VdH X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220127_120519_800542_0C5A2595 X-CRM114-Status: GOOD ( 14.43 ) 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 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 --- 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) -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel