From nobody Mon Feb 9 23:59:54 2026 Delivered-To: importer@patchew.org Received-SPF: none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org ARC-Seal: i=1; a=rsa-sha256; t=1565631096; cv=none; d=zoho.com; s=zohoarc; b=Y2J952HOXZ3BZyNkQFo0ZL/q0hRIfsQvDasWKJJ579NQdjLiJTpKMys1slzkh7RbuLRc9H/o/+mrXz3toP6IEco09Nx93Q4ryZ8ymx61bTJiyqWFoVYKuh8HWo5qudMlxeh4ZauV7xlOu8nEy13eUHTiUCVBtGl+8yc5Avs1LPc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1565631096; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=/s5EPjYegcOAe62m+pveZEHcZyiV91rrUeU5gXuqjVY=; b=U2CBMGhUFvFBw7/TMp0NYVy3E3DtcD89ZH46xbCqMPSAVGLvv+ssLbTzzFydEdwbBxDYJLOiAD+XBwUGForArlzbWddbPleIkpsuMKh1L/YdVZpdanHbSo5ox0Uce6lWop7n7HuRvywt4wjxLWGncAz4jEv32J9U3Iw2SN2sEas= ARC-Authentication-Results: i=1; mx.zoho.com; spf=none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1565631096683478.80030305901096; Mon, 12 Aug 2019 10:31:36 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hxE9W-0006iK-Lg; Mon, 12 Aug 2019 17:30:38 +0000 Received: from us1-rack-dfw2.inumbo.com ([104.130.134.6]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hxE9V-0006ha-Ev for xen-devel@lists.xenproject.org; Mon, 12 Aug 2019 17:30:37 +0000 Received: from foss.arm.com (unknown [217.140.110.172]) by us1-rack-dfw2.inumbo.com (Halon) with ESMTP id e555a358-bd26-11e9-8980-bc764e045a96; Mon, 12 Aug 2019 17:30:36 +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 60AA51715; Mon, 12 Aug 2019 10:30:36 -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 AF5953F706; Mon, 12 Aug 2019 10:30:35 -0700 (PDT) X-Inumbo-ID: e555a358-bd26-11e9-8980-bc764e045a96 From: Julien Grall To: xen-devel@lists.xenproject.org Date: Mon, 12 Aug 2019 18:30:01 +0100 Message-Id: <20190812173019.11956-11-julien.grall@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190812173019.11956-1-julien.grall@arm.com> References: <20190812173019.11956-1-julien.grall@arm.com> Subject: [Xen-devel] [PATCH v3 10/28] xen/arm32: head: Don't clobber r14/lr in the macro PRINT 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 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" The current implementation of the macro PRINT will clobber r14/lr. This means the user should save r14 if it cares about it. Follow-up patches will introduce more use of PRINT in places where lr should be preserved. Rather than requiring all the user to preserve lr, the macro PRINT is modified to save and restore it. While the comment state r3 will be clobbered, this is not the case. So PRINT will use r3 to preserve lr. Lastly, take the opportunity to move the comment on top of PRINT and use PRINT in init_uart. Both changes will be helpful in a follow-up patch. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini --- Changes in v3: - Add Stefano's acked-by Changes in v2: - Patch added --- xen/arch/arm/arm32/head.S | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index 8b4c8a4714..b54331c19d 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -64,15 +64,20 @@ * r14 - LR * r15 - PC */ -/* Macro to print a string to the UART, if there is one. - * Clobbers r0-r3. */ #ifdef CONFIG_EARLY_PRINTK -#define PRINT(_s) \ - adr r0, 98f ; \ - bl puts ; \ - b 99f ; \ -98: .asciz _s ; \ - .align 2 ; \ +/* + * Macro to print a string to the UART, if there is one. + * + * Clobbers r0 - r3 + */ +#define PRINT(_s) \ + mov r3, lr ;\ + adr r0, 98f ;\ + bl puts ;\ + mov lr, r3 ;\ + b 99f ;\ +98: .asciz _s ;\ + .align 2 ;\ 99: #else /* CONFIG_EARLY_PRINTK */ #define PRINT(s) @@ -500,10 +505,8 @@ init_uart: #ifdef EARLY_PRINTK_INIT_UART early_uart_init r11, r1, r2 #endif - adr r0, 1f - b puts /* Jump to puts */ -1: .asciz "- UART enabled -\r\n" - .align 4 + PRINT("- UART enabled -\r\n") + mov pc, lr =20 /* * Print early debug messages. --=20 2.11.0 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel