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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 46ACCC43441 for ; Tue, 27 Nov 2018 23:56:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05A2620851 for ; Tue, 27 Nov 2018 23:56:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="QemfJRMV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 05A2620851 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726773AbeK1Kze (ORCPT ); Wed, 28 Nov 2018 05:55:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:60678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726354AbeK1Kze (ORCPT ); Wed, 28 Nov 2018 05:55:34 -0500 Received: from devnote (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 E3172206B6; Tue, 27 Nov 2018 23:55:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543362959; bh=NwmAfCvjrtIu027XRWGklT99k8OoEMCM0fPWNpvoAg0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QemfJRMV2NexJ1aagIkbv5ABn1RPDKSF5IcBHqwkQzIIQZfhArXbrpK8XuVzdL2aj DzNmuUB2fKXreUqHKB6OA8TaxauVO1xmSiZt+rvK2ib3TWH05DEvYvshcCa8fE08SE qMxT2c0A22c/GGWClHTC0yGWLiMbVacuUYc1Eg4Q= Date: Wed, 28 Nov 2018 08:55:55 +0900 From: Masami Hiramatsu To: Steven Rostedt Cc: Will Deacon , Masami Hiramatsu , Catalin Marinas , Naresh Kamboju , Mark Rutland , Ingo Molnar , Masami Hiramatsu , linux-kernel@vger.kernel.org, stable@vger.kernel.org, AKASHI Takahiro Subject: Re: [PATCH] arm64: ftrace: Fix to enable syscall events on arm64 Message-Id: <20181128085555.a8987cbe18aa6d1d1f0a827e@kernel.org> In-Reply-To: <20181127131859.79ce7da9@gandalf.local.home> References: <154333618522.27355.8094935453351562295.stgit@devbox> <20181127165848.GA19569@arm.com> <20181127131859.79ce7da9@gandalf.local.home> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Will, On Tue, 27 Nov 2018 13:18:59 -0500 Steven Rostedt wrote: > On Tue, 27 Nov 2018 16:58:49 +0000 > Will Deacon wrote: > > > This looks fine to me, but I'm curious about whether this is supposed to > > work with compat syscalls as well, where the prefix is "__arm64_compat_". > > > > If we broadly follow the x86 lead, we'd have: > > > > return (!strncmp(sym, "__arm64_", 8) && !strcmp(sym + 8, name)) || > > (!strncmp(sym, "__arm64_compat_", 15) && !strcmp(sym + 15, name)); > > > > Do we need to handle compat (i.e. 32-bit) tasks here? > > Only if you want to trace compat syscalls as well ;-) Actually I thought about that, but I found below comment in arch/arm64/include/asm/ftrace.h * Because AArch32 mode does not share the same syscall table with AArch64, * tracing compat syscalls may result in reporting bogus syscalls or even * hang-up, so just do not trace them. That's why I dropped compat syscall support. Thank you, -- Masami Hiramatsu