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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 7AB27C04AB4 for ; Tue, 14 May 2019 10:18:48 +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 C3DD62085A for ; Tue, 14 May 2019 10:18:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C3DD62085A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au 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 453DDP1vK4zDqMF for ; Tue, 14 May 2019 20:18:45 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 453DC04h3RzDqJ3 for ; Tue, 14 May 2019 20:17:32 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 453DBx2lqDz9sNK; Tue, 14 May 2019 20:17:29 +1000 (AEST) From: Michael Ellerman To: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Greg KH , erhard_f@mailbox.org, Michael Neuling Subject: Re: [PATCH stable 4.9] powerpc/lib: fix code patching during early init on PPC32 In-Reply-To: <015040d922a68fa15c81879cc2fc9ed7ac106e60.1557827275.git.christophe.leroy@c-s.fr> References: <015040d922a68fa15c81879cc2fc9ed7ac106e60.1557827275.git.christophe.leroy@c-s.fr> Date: Tue, 14 May 2019 20:17:27 +1000 Message-ID: <87y339s5l4.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "stable@vger.kernel.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Christophe Leroy writes: > [Backport of upstream commit b45ba4a51cde29b2939365ef0c07ad34c8321789] > > On powerpc32, patch_instruction() is called by apply_feature_fixups() > which is called from early_init() > > There is the following note in front of early_init(): > * Note that the kernel may be running at an address which is different > * from the address that it was linked at, so we must use RELOC/PTRRELOC > * to access static data (including strings). -- paulus > > Therefore init_mem_is_free must be accessed with PTRRELOC() > > Fixes: 1c38a84d4586 ("powerpc: Avoid code patching freed init sections") > Link: https://bugzilla.kernel.org/show_bug.cgi?id=203597 > Signed-off-by: Christophe Leroy > > --- > Can't apply the upstream commit as such due to several of other unrelated stuff > like STRICT_KERNEL_RWX which are missing for instance. > So instead, using same approach as for commit 252eb55816a6f69ef9464cad303cdb3326cdc61d Yeah this looks good to me. Though should we keep the same subject as the upstream commit this is sort of a backport of? That might make it simpler for people who are trying to keep track of things? ie. "powerpc/lib: fix book3s/32 boot failure due to code patching" cheers > diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c > index 14535ad4cdd1..c312955977ce 100644 > --- a/arch/powerpc/lib/code-patching.c > +++ b/arch/powerpc/lib/code-patching.c > @@ -23,7 +23,7 @@ int patch_instruction(unsigned int *addr, unsigned int instr) > int err; > > /* Make sure we aren't patching a freed init section */ > - if (init_mem_is_free && init_section_contains(addr, 4)) { > + if (*PTRRELOC(&init_mem_is_free) && init_section_contains(addr, 4)) { > pr_debug("Skipping init section patching addr: 0x%px\n", addr); > return 0; > } > -- > 2.13.3