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=unavailable 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 600E8C47E49 for ; Wed, 30 Oct 2019 15:01:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 31F0220874 for ; Wed, 30 Oct 2019 15:01:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726879AbfJ3PBC (ORCPT ); Wed, 30 Oct 2019 11:01:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:47620 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726246AbfJ3PBC (ORCPT ); Wed, 30 Oct 2019 11:01:02 -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 25C5BB232; Wed, 30 Oct 2019 15:01:00 +0000 (UTC) Date: Wed, 30 Oct 2019 16:00:58 +0100 (CET) From: Miroslav Benes To: Mark Rutland cc: linux-arm-kernel@lists.infradead.org, Steven Rostedt , 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() In-Reply-To: <20191029165832.33606-2-mark.rutland@arm.com> Message-ID: References: <20191029165832.33606-1-mark.rutland@arm.com> <20191029165832.33606-2-mark.rutland@arm.com> 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 On Tue, 29 Oct 2019, 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 > Cc: Torsten Duwe Reviewed-by: Miroslav Benes M