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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 8C9FCC43441 for ; Wed, 28 Nov 2018 12:04:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A03F208E7 for ; Wed, 28 Nov 2018 12:04:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A03F208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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 S1728020AbeK1XGL (ORCPT ); Wed, 28 Nov 2018 18:06:11 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:37218 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727673AbeK1XGL (ORCPT ); Wed, 28 Nov 2018 18:06:11 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1003137D0; Wed, 28 Nov 2018 04:04:45 -0800 (PST) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D46623F59C; Wed, 28 Nov 2018 04:04:44 -0800 (PST) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 0133E1AE0808; Wed, 28 Nov 2018 12:05:02 +0000 (GMT) Date: Wed, 28 Nov 2018 12:05:02 +0000 From: Will Deacon To: Masami Hiramatsu Cc: Steven Rostedt , 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: <20181128120502.GC24868@arm.com> References: <154333618522.27355.8094935453351562295.stgit@devbox> <20181127165848.GA19569@arm.com> <20181127131859.79ce7da9@gandalf.local.home> <20181128085555.a8987cbe18aa6d1d1f0a827e@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181128085555.a8987cbe18aa6d1d1f0a827e@kernel.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Masami, On Wed, Nov 28, 2018 at 08:55:55AM +0900, Masami Hiramatsu wrote: > 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. Ok! Then please add a comment to arch_syscall_match_sym_name() along those lines, and you can add my ack: Acked-by: Will Deacon Thanks, Will