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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 C1EF2C3A589 for ; Tue, 20 Aug 2019 09:27:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99F3222CF9 for ; Tue, 20 Aug 2019 09:27:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729518AbfHTJ1r (ORCPT ); Tue, 20 Aug 2019 05:27:47 -0400 Received: from mx2.suse.de ([195.135.220.15]:43680 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729198AbfHTJ1r (ORCPT ); Tue, 20 Aug 2019 05:27:47 -0400 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 3195DADD9; Tue, 20 Aug 2019 09:27:46 +0000 (UTC) Date: Tue, 20 Aug 2019 11:27:38 +0200 (CEST) From: Miroslav Benes To: Jisheng Zhang cc: Catalin Marinas , Will Deacon , Steven Rostedt , Mark Rutland , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Torsten Duwe Subject: Re: [PATCH 1/3] ftrace: introdue ftrace_call_init In-Reply-To: <20190819191622.57050fdf@xhacker.debian> Message-ID: References: <20190819191530.0f47b9b1@xhacker.debian> <20190819191622.57050fdf@xhacker.debian> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, 19 Aug 2019, Jisheng Zhang wrote: > On some arch, the FTRACE_WITH_REGS is implemented with gcc's > -fpatchable-function-entry (=2), gcc adds 2 NOPs at the beginning > of each function, so this makes the MCOUNT_ADDR useless. In ftrace > common framework, MCOUNT_ADDR is mostly used to "init" the nop, so > let's introcude ftrace_call_init(). > > Signed-off-by: Jisheng Zhang > --- > include/linux/ftrace.h | 1 + > kernel/trace/ftrace.c | 4 ++++ > 2 files changed, 5 insertions(+) > > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > index 8a8cb3c401b2..8175ffb671f0 100644 > --- a/include/linux/ftrace.h > +++ b/include/linux/ftrace.h > @@ -458,6 +458,7 @@ extern void ftrace_regs_caller(void); > extern void ftrace_call(void); > extern void ftrace_regs_call(void); > extern void mcount_call(void); > +extern int ftrace_call_init(struct module *mod, struct dyn_ftrace *rec); > > void ftrace_modify_all_code(int command); > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index eca34503f178..9df5a66a6811 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -2500,7 +2500,11 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) > if (unlikely(ftrace_disabled)) > return 0; > > +#ifdef MCOUNT_ADDR > ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); > +#else > + ret = ftrace_call_init(mod, rec); > +#endif > if (ret) { > ftrace_bug_type = FTRACE_BUG_INIT; > ftrace_bug(ret, rec); I may be missing something, but the patch does not seem to be complete. There is no ftrace_call_init() implemented. MCOUNT_ADDR is still defined, so it does not change much. I don't think it is what Mark had in his mind. Miroslav