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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9E94C43613 for ; Tue, 18 Dec 2018 14:57:59 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EE84721852 for ; Tue, 18 Dec 2018 14:57:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE84721852 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43K1NN6hvMzDqY0 for ; Wed, 19 Dec 2018 01:57:56 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43K1Kc5jC0zDqSN for ; Wed, 19 Dec 2018 01:55:32 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 43K1KV0wPXz9v0vZ; Tue, 18 Dec 2018 15:55:26 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id HAKZSdOcLbiJ; Tue, 18 Dec 2018 15:55:26 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 43K1KV0PFDz9v0vY; Tue, 18 Dec 2018 15:55:26 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 791C28B849; Tue, 18 Dec 2018 15:55:27 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id iK2ajVVAcyhI; Tue, 18 Dec 2018 15:55:27 +0100 (CET) Received: from PO15451 (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 052108B848; Tue, 18 Dec 2018 15:55:26 +0100 (CET) Subject: Re: [PATCH v1 03/13] powerpc/mm/32s: rework mmu_mapin_ram() To: =?UTF-8?Q?Jonathan_Neusch=c3=a4fer?= References: <8835330baa77d88e0267b0b1215b78c991e6d17a.1543517818.git.christophe.leroy@c-s.fr> <20181203215558.GK15324@latitude> <84624899-bbda-9f08-2527-151fddbd1b01@c-s.fr> <20181217012837.GT15324@latitude> <18ba3a7c-ebfa-66aa-e231-b56985d0e89a@c-s.fr> <20181218030538.GA24278@latitude> <9a39d910-2a05-3ce7-c949-296db2d458b9@c-s.fr> <20181218140714.GC24278@latitude> <96539c09-ea57-43d6-bae9-7371235b175f@c-s.fr> From: Christophe Leroy Message-ID: Date: Tue, 18 Dec 2018 15:55:26 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 MIME-Version: 1.0 In-Reply-To: <96539c09-ea57-43d6-bae9-7371235b175f@c-s.fr> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Le 18/12/2018 à 15:15, Christophe Leroy a écrit : > > > Le 18/12/2018 à 15:07, Jonathan Neuschäfer a écrit : >> On Tue, Dec 18, 2018 at 09:18:42AM +0000, Christophe Leroy wrote: >>> The only difference I see then are the flags. Everything else is seems >>> identical. >>> >>> I know you tried already, but would you mind trying once more with the >>> following change ? >>> >> [...] >>> - setbat(idx, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT); >>> + setbat(idx, PAGE_OFFSET + base, base, size, PAGE_KERNEL_X); >> >> Good call, with this workaround on top of patches 1-3, it boots again: >> >> # mount -t debugfs d /sys/kernel/debug >> # cat /sys/kernel/debug/powerpc/block_address_translation >> ---[ Instruction Block Address Translation ]--- >> 0: 0xc0000000-0xc0ffffff 0x00000000 Kernel EXEC >> 1: - >> 2: 0xc1000000-0xc17fffff 0x01000000 Kernel EXEC >> 3: - >> 4: 0xd0000000-0xd1ffffff 0x10000000 Kernel EXEC >> 5: - >> 6: - >> 7: - >> >> ---[ Data Block Address Translation ]--- >> 0: 0xc0000000-0xc0ffffff 0x00000000 Kernel RW >> 1: 0xfffe0000-0xffffffff 0x0d000000 Kernel RW no cache guarded >> 2: 0xc1000000-0xc17fffff 0x01000000 Kernel RW >> 3: - >> 4: 0xd0000000-0xd1ffffff 0x10000000 Kernel RW >> 5: - >> 6: - >> 7: - >> >>> I think we may have some code trying to modify the kernel text >>> without using >>> code patching functions. >> >> Is there any faster way than to sprinkle some printks in setup_kernel >> and try to find the guilty piece of code this way? > > Can you start with the serie > https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=75072 ? Ok, the thing I was thinking about was the MMU_init_hw() but it is called before mapin_ram() so it should not be a problem. Not sure that serie improves anything at all here. So there must be something else, pretty early (before the system is able to properly handle and display an Oops for write to RO area.) Does anybody have an idea of what it can be ? Christophe > > Christophe > >> >> >> Jonathan >>