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=-15.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_2 autolearn=ham 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 6B33FC433DB for ; Thu, 25 Feb 2021 14:45:56 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 1337764E28 for ; Thu, 25 Feb 2021 14:45:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1337764E28 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Ea8gnPL6xGBLQszSNlN8CPYFD7jrkgOcTazF8cmLW5E=; b=Xf0lQsc3hnLww1IC5Rs0ygKpz GU1fTKkZWC+mcsGaZQZqTPv7bNRyyE0pag6xcRVJ9/wreZ9ZJQvTGVfPGRInIIstOh75bubM4cgAY rI1BOyq3jZh8jzlZmTC9NouyrzWuFLRggwuRtyFNIseEowrWKzWQ8WHSVXL/Ixn9i3TszoGCzfSP1 Crg8xsKPsDtMb5TILU0KyaCEL2/RAlyrZoeh9wFmoSYrtt3IY6Yc21t8sYZ3stj4T0fTi4wDFIjue Easw/sPnEsa7WSxQ7KfKan8rDh6Dto3WCua84lNJSGf9LnPpNRg217sAy/IlHkXJQ34Ii8D8XZ0mz zG99UzhQA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lFHsX-0002Ps-FN; Thu, 25 Feb 2021 14:44:33 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lFHsU-0002Oq-Bz for linux-arm-kernel@lists.infradead.org; Thu, 25 Feb 2021 14:44:31 +0000 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E0C5564EC3; Thu, 25 Feb 2021 14:44:27 +0000 (UTC) Date: Thu, 25 Feb 2021 09:44:26 -0500 From: Steven Rostedt To: Li Huafei Subject: Re: [PATCH] recordmcount: Fix the wrong use of w* in arm64_is_fake_mcount() Message-ID: <20210225094426.7729b9cc@gandalf.local.home> In-Reply-To: <20210225140747.10818-1-lihuafei1@huawei.com> References: <20210225140747.10818-1-lihuafei1@huawei.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210225_094430_829781_7CED87AB X-CRM114-Status: GOOD ( 26.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , linux-kernel@vger.kernel.org, christophe.leroy@csgroup.eu, zhangjinhao2@huawei.com, yangjihong1@huawei.com, gregory.herrero@oracle.com, xukuohai@huawei.com, Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This requires an acked-by from one of the ARM64 maintainers. -- Steve On Thu, 25 Feb 2021 22:07:47 +0800 Li Huafei wrote: > When cross-compiling the kernel, the endian of the target machine and > the local machine may not match, at this time the recordmcount tool > needs byte reversal when processing elf's variables to get the correct > value. w* callback function is used to solve this problem, w is used for > 4-byte variable processing, while w8 is used for 8-byte. > > arm64_is_fake_mcount() is used to filter '_mcount' relocations that are > not used by ftrace. In arm64_is_fake_mcount(), rp->info is 8 bytes in > size, but w is used. This causes arm64_is_fake_mcount() to get the wrong > type of relocation when we cross-compile the arm64_be kernel image on an > x86_le machine, and all valid '_mcount' is filtered out. The > recordmcount tool does not collect any mcount function call locations. > At kernel startup, the following ftrace log is seen: > > ftrace: No functions to be traced? > > and thus ftrace cannot be used. > > Using w8 to get the value of rp->r_info will fix the problem. > > Fixes: ea0eada45632 ("recordmcount: only record relocation of type > R_AARCH64_CALL26 on arm64") > Signed-off-by: Li Huafei > --- > scripts/recordmcount.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c > index b9c2ee7ab43f..cce12e1971d8 100644 > --- a/scripts/recordmcount.c > +++ b/scripts/recordmcount.c > @@ -438,7 +438,7 @@ static int arm_is_fake_mcount(Elf32_Rel const *rp) > > static int arm64_is_fake_mcount(Elf64_Rel const *rp) > { > - return ELF64_R_TYPE(w(rp->r_info)) != R_AARCH64_CALL26; > + return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26; > } > > /* 64-bit EM_MIPS has weird ELF64_Rela.r_info. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel