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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 8BCFFCA9ED3 for ; Mon, 4 Nov 2019 13:38:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 630042184C for ; Mon, 4 Nov 2019 13:38:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729193AbfKDNil (ORCPT ); Mon, 4 Nov 2019 08:38:41 -0500 Received: from foss.arm.com ([217.140.110.172]:43224 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727236AbfKDNil (ORCPT ); Mon, 4 Nov 2019 08:38:41 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 97DD81FB; Mon, 4 Nov 2019 05:38:40 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5FE8D3F6C4; Mon, 4 Nov 2019 05:38:38 -0800 (PST) Date: Mon, 4 Nov 2019 13:38:36 +0000 From: Mark Rutland To: Steven Rostedt Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, amit.kachhap@arm.com, catalin.marinas@arm.com, deller@gmx.de, duwe@suse.de, James.Bottomley@HansenPartnership.com, james.morse@arm.com, jeyu@kernel.org, jpoimboe@redhat.com, jthierry@redhat.com, linux-parisc@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, svens@stackframe.org, takahiro.akashi@linaro.org, will@kernel.org Subject: Re: [PATCHv2 1/8] ftrace: add ftrace_init_nop() Message-ID: <20191104133836.GF45140@lakrids.cambridge.arm.com> References: <20191029165832.33606-1-mark.rutland@arm.com> <20191029165832.33606-2-mark.rutland@arm.com> <20191104081620.732320a8@grimm.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191104081620.732320a8@grimm.local.home> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 04, 2019 at 08:16:20AM -0500, Steven Rostedt wrote: > On Tue, 29 Oct 2019 16:58:25 +0000 > Mark Rutland wrote: > > > Architectures may need to perform special initialization of ftrace > > callsites, and today they do so by special-casing ftrace_make_nop() when > > the expected branch address is MCOUNT_ADDR. In some cases (e.g. for > > patchable-function-entry), we don't have an mcount-like symbol and don't > > want a synthetic MCOUNT_ADDR, but we may need to perform some > > initialization of callsites. > > > > To make it possible to separate initialization from runtime > > modification, and to handle cases without an mcount-like symbol, this > > patch adds an optional ftrace_init_nop() function that architectures can > > implement, which does not pass a branch address. > > > > Where an architecture does not provide ftrace_init_nop(), we will fall > > back to the existing behaviour of calling ftrace_make_nop() with > > MCOUNT_ADDR. > > > > At the same time, ftrace_code_disable() is renamed to > > ftrace_nop_initialize() to make it clearer that it is intended to > > intialize a callsite into a disabled state, and is not for disabling a > > callsite that has been runtime enabled. The kerneldoc description of rec > > arguments is updated to cover non-mcount callsites. > > > > Signed-off-by: Mark Rutland > > Reviewed-by: Ard Biesheuvel > > Cc: Ingo Molnar > > Cc: Steven Rostedt > > Reviewed-by: Steven Rostedt (VMware) Thanks! Just to check, are you happy if this were to go via the arm64 tree with the rest of the patches? Mark.