From patchwork Mon Jul 22 21:39:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 11053513 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 404571398 for ; Mon, 22 Jul 2019 21:41:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3193F2847E for ; Mon, 22 Jul 2019 21:41:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 25E20284DB; Mon, 22 Jul 2019 21:41:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id BF72E2847E for ; Mon, 22 Jul 2019 21:41:41 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hpg2j-0002nT-S6; Mon, 22 Jul 2019 21:40:25 +0000 Received: from us1-rack-dfw2.inumbo.com ([104.130.134.6]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hpg2i-0002jm-5e for xen-devel@lists.xenproject.org; Mon, 22 Jul 2019 21:40:24 +0000 X-Inumbo-ID: 4f58cf37-acc9-11e9-8980-bc764e045a96 Received: from foss.arm.com (unknown [217.140.110.172]) by us1-rack-dfw2.inumbo.com (Halon) with ESMTP id 4f58cf37-acc9-11e9-8980-bc764e045a96; Mon, 22 Jul 2019 21:40:23 +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 F3E3A152F; Mon, 22 Jul 2019 14:40:22 -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 4CC763F71F; Mon, 22 Jul 2019 14:40:22 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xenproject.org Date: Mon, 22 Jul 2019 22:39:42 +0100 Message-Id: <20190722213958.5761-20-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 19/35] xen/arm32: head: Add a macro to move an immediate constant into a 32-bit register 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" X-Virus-Scanned: ClamAV using ClamSMTP The current boot code is using the pattern ldr rX, =... to move an immediate constant into a 32-bit register. This pattern implies to load the immediate constant from a literal pool, meaning a memory access will be performed. The memory access can be avoided by using movw/movt instructions. A new macro is introduced to move an immediate constant into a 32-bit register without a memory load. Follow-up patches will make use of it. Signed-off-by: Julien Grall Acked-by: Stefano Stabellini --- Changes in v2: - Patch added --- xen/arch/arm/arm32/head.S | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index 18ded49a04..99f4af18d8 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -37,6 +37,15 @@ #endif /* + * Move an immediate constant into a 32-bit register using movw/movt + * instructions. + */ +.macro mov_w reg, word + movw \reg, #:lower16:\word + movt \reg, #:upper16:\word +.endm + +/* * Common register usage in this file: * r0 - * r1 -