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 CE253CF6D28 for ; Wed, 2 Oct 2024 14:34:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:Mime-Version:References:In-Reply-To:Message-Id:Subject:Cc: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=nSHw6CWO4X22SEXCLmBQJtuHd+kee0vC4UTw6pETGbo=; b=jIPURsoHTh+e+nlzpN56aOkZzX IzqgttVcnPTDG/kjPxdAk/8jzU4+1awE4zK9rQraoWV+16Bam7aweAeq4othATOC8oYA2USLqTm9I lj3mgQiyVmxCqcEb2Z8zKJaMG6h/1Lr4R5rNj8RJqipxxQVhG2PIPnU2CfxuSysAwI5Fj0Z0XkGQj ABq7qkqMLVdmgfCiq4udJssh++5cd7JuLZMQ4tmGx3GqBTAAaJULr/Kl7bRguxLTS2k2aL1jwlpEm TUa5Kn0a6cmWv0U4YQ8YIEhicFv0lyG/jpd6X2jt7OAUUeBvv3GNFyNZTrVUNM2fRpIgjvG4WlG0/ hGzOHtWQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1sw0QK-00000006PQJ-1fTQ; Wed, 02 Oct 2024 14:33:52 +0000 Received: from nyc.source.kernel.org ([147.75.193.91]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1sw0Nm-00000006Okv-2E47 for linux-arm-kernel@lists.infradead.org; Wed, 02 Oct 2024 14:31:15 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 4E411A4336B; Wed, 2 Oct 2024 14:31:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67049C4CEC5; Wed, 2 Oct 2024 14:31:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727879473; bh=7QrNOvyhNom77KQGrs/t7eMr6qYJYQNHCPzn2XeEmZk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=eJKQKjtwuljUQETX3A01ZIMibs/ViHavZ74RNwceIvmWzOaQ5RnRGKG22YgnKlBut vfkpP2b4ZfHgZDr9i84lgp1trq+pD9VcWU9K8c9xat9EGT1pKlx2JHYN17t/UOiYOw iRM2aHuwdZ0ejp+4auqwjM2QJIEtyUxSybw/9523lYeYAACGiy5beFokFcCYXBAw3O sgbQ2QwIuR+W1/VO3diF34mCXir9CSb8JA5gNBZZmczNq3dYMPXic59LnyC7N/oyof 6Xx0Y5o1XX92jex1p1VnXPdcPsj7nYOGV6SU28hWvfk/it08ZluzzWtO6p1R7382I8 jSFURQZ7W0GNQ== Date: Wed, 2 Oct 2024 23:31:08 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: Will Deacon , Catalin Marinas , linux-arm-kernel@lists.infradead.org, Florent Revest , linux-trace-kernel@vger.kernel.org, LKML , Alexei Starovoitov , Jiri Olsa , Arnaldo Carvalho de Melo , Daniel Borkmann , Mark Rutland Subject: Re: [PATCH v14 04/19] function_graph: Replace fgraph_ret_regs with ftrace_regs Message-Id: <20241002233108.9e4c2aaa09b8532870016dc0@kernel.org> In-Reply-To: <20241001193234.2acb6147@gandalf.local.home> References: <172615368656.133222.2336770908714920670.stgit@devnote2> <172615373091.133222.1812791604518973124.stgit@devnote2> <20240915051144.445681c2@rorschach.local.home> <20240917095538.GA27384@willie-the-truck> <20240930145548.08c8f666@gandalf.local.home> <20241002081037.e9b825f7456ce4815eccad1b@kernel.org> <20241001193234.2acb6147@gandalf.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241002_073114_670319_4B801884 X-CRM114-Status: GOOD ( 19.86 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 1 Oct 2024 19:32:34 -0400 Steven Rostedt wrote: > On Wed, 2 Oct 2024 08:10:37 +0900 > Masami Hiramatsu (Google) wrote: > > > > > > I may add some compiler hacks to enforce this. Something like: > > > > > > struct ftrace_regs { > > > void *nothing_to_see_here; > > > }; > > > > Yeah, OK. But sizeof(fregs) may be changed. (Shouldn't we do too?) > > Honestly, I don't think anything should be doing a sizeof(struct ftrace_regs) > > Heck, perhaps we should make it totally zero! > > struct ftrace_regs { > long nothing_here[]; > }; > > If someone needs to allocate, then we could provide a: > > ftrace_regs_size() > > helper function. Ah, Indeed. > > > > > > > > > And then change the arch code to be something like: > > > > > > // in arch/arm64/include/asm/ftrace.h: > > > > > > struct arch_ftrace_regs { > > > /* x0 - x8 */ > > > unsigned long regs[9]; > > > > > > #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS > > > unsigned long direct_tramp; > > > #else > > > unsigned long __unused; > > > #endif > > > > > > unsigned long fp; > > > unsigned long lr; > > > > > > unsigned long sp; > > > unsigned long pc; > > > }; > > > > And if it is pt_regs compatible, > > > > #define arch_ftrace_regs pt_regs > > > > ? > > > > Only if it is fully pt_regs compatible. Yeah, OK, this is good idea. Thank you, > > -- Steve -- Masami Hiramatsu (Google)