From patchwork Mon Jul 22 21:39:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 11053543 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 4B8711398 for ; Mon, 22 Jul 2019 21:43:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3D0F32847E for ; Mon, 22 Jul 2019 21:43:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 319F8284DB; Mon, 22 Jul 2019 21:43:25 +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 C73722847E for ; Mon, 22 Jul 2019 21:43:24 +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 1hpg34-0003bm-OX; Mon, 22 Jul 2019 21:40:46 +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 1hpg2v-0003FY-KM for xen-devel@lists.xenproject.org; Mon, 22 Jul 2019 21:40:37 +0000 X-Inumbo-ID: 56e18d9c-acc9-11e9-a3cc-5319c96131f2 Received: from foss.arm.com (unknown [217.140.110.172]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTP id 56e18d9c-acc9-11e9-a3cc-5319c96131f2; Mon, 22 Jul 2019 21:40:35 +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 7D1291597; Mon, 22 Jul 2019 14:40:35 -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 CB1EA3F71F; Mon, 22 Jul 2019 14:40:34 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xenproject.org Date: Mon, 22 Jul 2019 22:39:56 +0100 Message-Id: <20190722213958.5761-34-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 33/35] xen/arm32: head: Rework and document launch() 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 Boot CPU and secondary CPUs will use different entry point to C code. At the moment, the decision on which entry to use is taken within launch(). In order to avoid using conditional instruction and make the call clearer, launch() is reworked to take in parameters the entry point and its arguments. Lastly, document the behavior and the main registers usage within the function. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini --- Changes in v2: - Patch added --- xen/arch/arm/arm32/head.S | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index e0f8c2e0cb..6d55a2119a 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -170,6 +170,11 @@ primary_switched: /* Use a virtual address to access the UART. */ mov_w r11, EARLY_UART_VIRTUAL_ADDRESS #endif + PRINT("- Ready -\r\n") + /* Setup the arguments for start_xen and jump to C world */ + mov r0, r10 /* r0 := Physical offset */ + mov r1, r8 /* r1 := paddr(FDT) */ + ldr r2, =start_xen b launch ENDPROC(start) @@ -234,6 +239,9 @@ secondary_switched: /* Use a virtual address to access the UART. */ mov_w r11, EARLY_UART_VIRTUAL_ADDRESS #endif + PRINT("- Ready -\r\n") + /* Jump to C world */ + ldr r2, =start_secondary b launch ENDPROC(init_secondary) @@ -578,19 +586,25 @@ setup_fixmap: mov pc, lr ENDPROC(setup_fixmap) +/* + * Setup the initial stack and jump to the C world + * + * Inputs: + * r0 : Argument 0 of the C function to call + * r1 : Argument 1 of the C function to call + * r2 : C entry point + * + * Clobbers r3 + */ launch: - PRINT("- Ready -\r\n") - - ldr r0, =init_data - add r0, #INITINFO_stack /* Find the boot-time stack */ - ldr sp, [r0] + ldr r3, =init_data + add r3, #INITINFO_stack /* Find the boot-time stack */ + ldr sp, [r3] add sp, #STACK_SIZE /* (which grows down from the top). */ sub sp, #CPUINFO_sizeof /* Make room for CPU save record */ - teq r12, #0 - moveq r0, r10 /* Marshal args: - phys_offset */ - moveq r1, r8 /* - DTB address */ - beq start_xen /* and disappear into the land of C */ - b start_secondary /* (to the appropriate entry point) */ + + /* Jump to C world */ + bx r2 ENDPROC(launch) /* Fail-stop */