From patchwork Mon Aug 12 17:30:12 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 11090279 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 554031395 for ; Mon, 12 Aug 2019 17:31:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 486BF283A5 for ; Mon, 12 Aug 2019 17:31:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3C9A1284E8; Mon, 12 Aug 2019 17:31:48 +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 D9A8F283A5 for ; Mon, 12 Aug 2019 17:31:47 +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 1hxE9g-0006v6-RG; Mon, 12 Aug 2019 17:30:48 +0000 Received: from us1-rack-dfw2.inumbo.com ([104.130.134.6]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hxE9f-0006tT-Jc for xen-devel@lists.xenproject.org; Mon, 12 Aug 2019 17:30:47 +0000 X-Inumbo-ID: eb29bb4c-bd26-11e9-8980-bc764e045a96 Received: from foss.arm.com (unknown [217.140.110.172]) by us1-rack-dfw2.inumbo.com (Halon) with ESMTP id eb29bb4c-bd26-11e9-8980-bc764e045a96; Mon, 12 Aug 2019 17:30:46 +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 3C15915AB; Mon, 12 Aug 2019 10:30:46 -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 8A9343F706; Mon, 12 Aug 2019 10:30:45 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xenproject.org Date: Mon, 12 Aug 2019 18:30:12 +0100 Message-Id: <20190812173019.11956-22-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 21/28] xen/arm32: head: Rework and document setup_fixmap() 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 At the moment, the fixmap table is only hooked when earlyprintk is used. This is fine today because in C land, the fixmap is not used by anyone until the the boot CPU is switching to the runtime page-tables. In the future, the boot CPU will not switch between page-tables to avoid TLB incoherency. Thus, the fixmap table will need to be always hooked beofre any use. Let's start doing it now in setup_fixmap(). Lastly, document the behavior and the main registers usage within the function. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini --- Changes in v3: - The unused label is now removed in the previous patch - Add Stefano's reviewed-by Changes in v2: - Patch added --- xen/arch/arm/arm32/head.S | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index 34fc9ffcee..ee5c3d2af8 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -541,8 +541,21 @@ identity_mapping_removed: mov pc, lr ENDPROC(remove_identity_mapping) +/* + * Map the UART in the fixmap (when earlyprintk is used) and hook the + * fixmap table in the page tables. + * + * The fixmap cannot be mapped in create_page_tables because it may + * clash with the 1:1 mapping. + * + * Inputs: + * r10: Physical offset + * r11: Early UART base physical address + * + * Clobbers r1 - r4 + */ setup_fixmap: -#if defined(CONFIG_EARLY_PRINTK) /* Fixmap is only used by early printk */ +#if defined(CONFIG_EARLY_PRINTK) /* Add UART to the fixmap table */ ldr r1, =xen_fixmap /* r1 := vaddr (xen_fixmap) */ lsr r2, r11, #THIRD_SHIFT @@ -551,6 +564,7 @@ setup_fixmap: orr r2, r2, #PT_LOWER(DEV_L3) /* r2:r3 := 4K dev map including UART */ mov r3, #0x0 strd r2, r3, [r1, #(FIXMAP_CONSOLE*8)] /* Map it in the first fixmap's slot */ +#endif /* Map fixmap into boot_second */ ldr r1, =boot_second /* r1 := vaddr (boot_second) */ @@ -565,7 +579,7 @@ setup_fixmap: /* Ensure any page table updates made above have occurred. */ dsb nshst -#endif + mov pc, lr ENDPROC(setup_fixmap)