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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 F359FCA9EC3 for ; Thu, 31 Oct 2019 11:42:36 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id BF6EE2086D for ; Thu, 31 Oct 2019 11:42:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="YYLQ+FIB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF6EE2086D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: 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=vcXr3Ua1x5pQMO47gESsMjRXmkvvihzw9lEBocCjoII=; b=YYLQ+FIBAaRIEl pfABR4bQqJAq5JOhaT0HaSt+yPLRTLCQsP88MY/0XVKGjVTvkBwLyW0OyWGZVxycY4nUFiux9gyfp iu0RQgbWqxZ8kzuIkc3AcRCKsf/OiNE0NQw3GInpooeRuUcQPLkSiLYTvBzwWHCuCGFtxSKmRbjRN C7WRyJ9HSfoFkdOejDO6nj0iCA1SbvHA/kSz90W/hKyA3FMUfkNm7K3FKhR+Ledo0WzIcCvVYTEWD I+rR9y1PWzIiw8gHu7w3AhfD3ODGM8hnot5Pc8lDmrTgAwFx+cbvzlQwJu1mXTPlZofOfiH9WDWv4 ECNgP3NSoimzsZbjwcfg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iQ8qU-000635-8q; Thu, 31 Oct 2019 11:42:30 +0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iQ8qR-00062N-LK for linux-arm-kernel@lists.infradead.org; Thu, 31 Oct 2019 11:42:29 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 83BABAF7A; Thu, 31 Oct 2019 11:42:25 +0000 (UTC) Date: Thu, 31 Oct 2019 12:42:23 +0100 From: Torsten Duwe To: Mark Rutland Subject: Re: [PATCHv2 2/8] module/ftrace: handle patchable-function-entry Message-ID: <20191031114223.GA11684@suse.de> References: <20191029165832.33606-1-mark.rutland@arm.com> <20191029165832.33606-3-mark.rutland@arm.com> <20191030150302.GA965@suse.de> <20191031090231.GA3340@blommer> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191031090231.GA3340@blommer> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191031_044227_841366_4BC12B0D X-CRM114-Status: GOOD ( 18.37 ) 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: jthierry@redhat.com, linux-parisc@vger.kernel.org, peterz@infradead.org, catalin.marinas@arm.com, Helge Deller , jpoimboe@redhat.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, "James E.J. Bottomley" , takahiro.akashi@linaro.org, will@kernel.org, mingo@redhat.com, james.morse@arm.com, Jessica Yu , amit.kachhap@arm.com, svens@stackframe.org, 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+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Oct 31, 2019 at 09:02:32AM +0000, Mark Rutland wrote: > On Wed, Oct 30, 2019 at 04:03:02PM +0100, Torsten Duwe wrote: > > On Tue, Oct 29, 2019 at 04:58:26PM +0000, Mark Rutland wrote: > > > > > > I built parisc generic-{32,64}bit_defconfig with DYNAMIC_FTRACE enabled, > > > and verified that the section made it into the .ko files for modules. > > > > This is because of remaining #ifdeffery in include/asm-generic/vmlinux.lds.h: > > > > #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY > > #define MCOUNT_REC() . = ALIGN(8); \ > > __start_mcount_loc = .; \ > > KEEP(*(__patchable_function_entries)) \ > > __stop_mcount_loc = .; > > #else > > #define MCOUNT_REC() . = ALIGN(8); \ > > __start_mcount_loc = .; \ > > KEEP(*(__mcount_loc)) \ > > __stop_mcount_loc = .; > > #endif > > For modules we use a combination of scripts/module-common.lds and an > architecture's own module.lds, not vmlinux.lds.h. So I don't think the above is > relevant for modules. Sure, this is only loosely related,... > I agree that the CC_USING_PATCHABLE_FUNCTION_ENTRY ifdeffery could be > simplified, and that it would be nice to consistently use > FTRACE_CALLSITE_SECTION if we can. However, the generic linker script doesn't > include anything, and I don't see a good location for that to live. > > What I could do is add an explicit comment: > > /* > * The ftrace call sites are logged to a section whose name depends on the > * compiler option used. A given kernel image will only use one, AKA > * FTRACE_CALLSITE_SECTION. We capture all of them here to avoid header > * dependencies. > */ > #define MCOUNT_REC() \ > . = ALIGN(8); \ > __start_mcount_loc = .; \ > KEEP(*(__patchable_function_entries)) \ > KEEP(*(__mcount_loc)) \ > __stop_mcount_loc = .; > > ... which should make the dependency clear. Does that sound good to you? Beautiful. I just didn't want to miss the opportunity to have this cleaned up as well, and deemed this patch "closest" because of the definition of FTRACE_CALLSITE_SECTION. Put it where you see it fit best. Thanks, Torsten _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel