From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 28D0EC433EF for ; Mon, 18 Apr 2022 15:09:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=PG01N55Xx7vVWEz2jyCquoiHL9hZkvnfwzFpNRc1cV0=; b=PT0tX1p+gYWIVW H1DpqvIAbXQgiVCDfLP/GaiEu60z1tUaLarp8+4h6aHWpMtHUGotPDAbLdJBnuE6jwcz+e3yU15eS ZiRM8ja8W37LZsP0+DYaApLQG51GQAAG9BzdWcH8DJIF2Y6z8pWRydH8Rpot1+T2friyZp/ykT2nt ng98s1RqZ8eR9Eyu4oflMoECFnQn+k0mZb5AAch15hQzKVnbHrsEvwcB8I6wvX9FX6w5C+MMnh5ax NJks919YUrz8soqJ3V8LcZ1sSgwbqj8TjibRs7HPapmYe9FdimIMtEWBxWXZIfF8Xi3v5x8j3uEDk 6iXfLNYpuqQmGkBQJjDg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngSzE-00HPLS-4I; Mon, 18 Apr 2022 15:08:20 +0000 Received: from out28-147.mail.aliyun.com ([115.124.28.147]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngSz9-00HPK4-Mo for linux-arm-kernel@lists.infradead.org; Mon, 18 Apr 2022 15:08:17 +0000 X-Alimail-AntiSpam: AC=CONTINUE; BC=0.1217452|-1; CH=green; DM=|CONTINUE|false|; DS=CONTINUE|ham_regular_dialog|0.0823759-0.00362085-0.914003; FP=0|0|0|0|0|-1|-1|-1; HT=ay29a033018047212; MF=victor@allwinnertech.com; NM=1; PH=DS; RN=11; RT=11; SR=0; TI=SMTPD_---.NT4Udz._1650294482; Received: from 192.168.10.102(mailfrom:victor@allwinnertech.com fp:SMTPD_---.NT4Udz._1650294482) by smtp.aliyun-inc.com(11.95.168.178); Mon, 18 Apr 2022 23:08:03 +0800 Message-ID: <0fa192d1-b6cc-4a8a-c319-36471cba79e8@allwinnertech.com> Date: Mon, 18 Apr 2022 23:08:09 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH] ARM: mmu: fix access to illegal address when using earlycon & memblock=debug Content-Language: en-GB To: Linus Walleij Cc: linux@armlinux.org.uk, rmk+kernel@armlinux.org.uk, yanfei.xu@windriver.com, ardb@kernel.org, tglx@linutronix.de, mirq-linux@rere.qmqm.pl, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, allwinner-opensource-support@allwinnertech.com References: <20220316023356.120595-1-victor@allwinnertech.com> From: Victor Hassan In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220418_080815_986729_3E453B25 X-CRM114-Status: GOOD ( 12.36 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 18/04/2022 07:21, Linus Walleij wrote: > On Wed, Mar 16, 2022 at 3:33 AM Victor Hassan wrote: > >> earlycon uses fixmap to create a memory map, >> So we need to close earlycon before closing fixmap, >> otherwise printk will access illegal addresses. >> After creating a new memory map, we open earlycon again. >> >> Signed-off-by: Victor Hassan > > I think noone really noticed this because everyone on Arm systems > use CONFIG_DEBUG_LL, and that makes printascii hammer out > stuff on the console very early, it even accounts for whether we have > MMU on or not. > Hi Linus, Thank you for the reply. I used earlycon, in early_fixmap_shutdown, the base address of earlycon is in the critical stage of release and reassignment, so early_fixmap_shutdown -> create_mapping should not call earlycon in this process, and create_mapping has a lot of conditions that trigger print, memblock=debug just makes it easier to expose problems. > How are you using this on Arm even? What system and what serial > driver? I'm using serial driver 8250 on arm32, with cmdline: memblock=debug. CONFIG_SERIAL_8250=y CONFIG_SERIAL_8520_CONSOLE=y > > That said, it looks correct. > Acked-by: Linus Walleij Thank you. > > Yours, > Linus Walleij Sincerely, Victor Hassan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel