From patchwork Mon Jul 22 21:39:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 169458 Delivered-To: patch@linaro.org Received: by 2002:a92:4782:0:0:0:0:0 with SMTP id e2csp8013538ilk; Mon, 22 Jul 2019 14:42:53 -0700 (PDT) X-Google-Smtp-Source: APXvYqzjq1CZL7xTQGpTO4emDNa3qh/6RBa2UaQpj6gU0DTbotRbVSZrfC1pMGzRIUZlseJjoYHQ X-Received: by 2002:a6b:bc42:: with SMTP id m63mr52691711iof.189.1563831694010; Mon, 22 Jul 2019 14:41:34 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1563831694; cv=none; d=google.com; s=arc-20160816; b=AWqDbxqsaE84zHpjzah63H/8EoNZc6WWJqpkccbWcJMvH8/qxwIDH9kD5FjjKFVcAR YOFaNEghC0aYKYg+lJfdCX+ek7+aappHwA9g+bFMGw0i6t6I2kFj2B/t0ZnnPfjpMpdw ZhaDi9zs/Go6YDwKE+7TC2LRRF+cDkr1DVTyxH/F99Wp8dT84wvI//pdiEHalxCxMOu9 2h5sRDZBYngTlb6XoR2qo4QDuYIujAdEPPCrPW4LOnLJKiCaJxYIUX2DkXP3H6r09itn kjI6bLHYTf85u60N/5l2eqUVqRO2rOzaOaIfiY1pB9Td+tMrlSdnqhHVy/1r2YJhzGKl R1sQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:content-transfer-encoding:mime-version:cc :list-subscribe:list-help:list-post:list-unsubscribe:list-id :precedence:subject:references:in-reply-to:message-id:date:to:from; bh=Y6lpgC7dWmuUJ2PROGjWlsAg+wVvCc2iX4lSbZ7AX8g=; b=XwgTZ/KqWCWfvXoHsW41ZQCMCSn/7k4ew5QztidGG/qSnm7GmD28gJFUI5FOfHO5m3 2Zxr66oY05M39aGn5Zzek342qb410INA9xwSlwqzDQayG1xhK3yjy9q9WcyJeQiqbG3n N4wLFo8d8yDuOf0Bntqy4KN0g5hj+s1PTD6TrqitT4wpYcBhzKm4e8lZwqj3dcmV+zsM 3SgdXZkByfaAjgJtZcKKUAqq78PEXr0FEO2bHvUW3xg5fZA0mistCI9EuB+SjpgEEfrp IdHXqGdBsiDaWYuG6ZevplG6FYsyxkeTiFXb5xDttdMTyrT3hG0+Baw8wQHtYCo7a0sp sjMQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of xen-devel-bounces@lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org. [192.237.175.120]) by mx.google.com with ESMTPS id c24si13544083iod.82.2019.07.22.14.41.33 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 22 Jul 2019 14:41:34 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of xen-devel-bounces@lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of xen-devel-bounces@lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hpg2a-0002Vq-BA; Mon, 22 Jul 2019 21:40:16 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hpg2Y-0002TG-NT for xen-devel@lists.xenproject.org; Mon, 22 Jul 2019 21:40:14 +0000 X-Inumbo-ID: 48c8466a-acc9-11e9-bc40-333e19a5e78f Received: from foss.arm.com (unknown [217.140.110.172]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTP id 48c8466a-acc9-11e9-bc40-333e19a5e78f; Mon, 22 Jul 2019 21:40:12 +0000 (UTC) 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 03D7E153B; Mon, 22 Jul 2019 14:40:12 -0700 (PDT) Received: from e108454-lin.cambridge.arm.com (e108454-lin.cambridge.arm.com [10.1.196.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 51A093F71F; Mon, 22 Jul 2019 14:40:11 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xenproject.org Date: Mon, 22 Jul 2019 22:39:30 +0100 Message-Id: <20190722213958.5761-8-julien.grall@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190722213958.5761-1-julien.grall@arm.com> References: <20190722213958.5761-1-julien.grall@arm.com> Subject: [Xen-devel] [PATCH v2 07/35] xen/arm64: head: Rework and document check_cpu_mode() X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Julien Grall , Stefano Stabellini , Volodymyr Babchuk MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" A branch in the success case can be avoided by inverting the branch condition. At the same time, remove a pointless comment as Xen can only run at EL2. Lastly, document the behavior and the main registers usage within the function. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini --- Changes in v2: - Add Stefano's reviewed-by --- xen/arch/arm/arm64/head.S | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S index df797a1573..fbcc792ade 100644 --- a/xen/arch/arm/arm64/head.S +++ b/xen/arch/arm/arm64/head.S @@ -350,6 +350,13 @@ secondary_switched: b launch ENDPROC(init_secondary) +/* + * Check if the CPU has been booted in Hypervisor mode. + * This function will never return when the CPU is booted in another mode + * than Hypervisor mode. + * + * Clobbers x0 - x5 + */ check_cpu_mode: PRINT("- Current EL ") mrs x5, CurrentEL @@ -359,15 +366,13 @@ check_cpu_mode: /* Are we in EL2 */ cmp x5, #PSR_MODE_EL2t ccmp x5, #PSR_MODE_EL2h, #0x4, ne - b.eq el2 /* Yes */ - + b.ne 1f /* No */ + ret +1: /* OK, we're boned. */ PRINT("- Xen must be entered in NS EL2 mode -\r\n") PRINT("- Please update the bootloader -\r\n") b fail - -el2: PRINT("- Xen starting at EL2 -\r\n") - ret ENDPROC(check_cpu_mode) zero_bss: