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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5364BCA9EC5 for ; Wed, 30 Oct 2019 15:03:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DC8F20874 for ; Wed, 30 Oct 2019 15:03:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726269AbfJ3PDF (ORCPT ); Wed, 30 Oct 2019 11:03:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:48256 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726175AbfJ3PDF (ORCPT ); Wed, 30 Oct 2019 11:03:05 -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 D41D1B3B1; Wed, 30 Oct 2019 15:03:03 +0000 (UTC) Date: Wed, 30 Oct 2019 16:03:02 +0100 From: Torsten Duwe To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, Jessica Yu , Helge Deller , "James E.J. Bottomley" , linux-kernel@vger.kernel.org, amit.kachhap@arm.com, catalin.marinas@arm.com, james.morse@arm.com, jpoimboe@redhat.com, jthierry@redhat.com, linux-parisc@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, svens@stackframe.org, takahiro.akashi@linaro.org, will@kernel.org Subject: Re: [PATCHv2 2/8] module/ftrace: handle patchable-function-entry Message-ID: <20191030150302.GA965@suse.de> References: <20191029165832.33606-1-mark.rutland@arm.com> <20191029165832.33606-3-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191029165832.33606-3-mark.rutland@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Tue, Oct 29, 2019 at 04:58:26PM +0000, Mark Rutland wrote: > When using patchable-function-entry, the compiler will record the > callsites into a section named "__patchable_function_entries" rather > than "__mcount_loc". Let's abstract this difference behind a new > FTRACE_CALLSITE_SECTION, so that architectures don't have to handle this > explicitly (e.g. with custom module linker scripts). > > As parisc currently handles this explicitly, it is fixed up accordingly, > with its custom linker script removed. Since FTRACE_CALLSITE_SECTION is > only defined when DYNAMIC_FTRACE is selected, the parisc module loading > code is updated to only use the definition in that case. When > DYNAMIC_FTRACE is not selected, modules shouldn't have this section, so > this removes some redundant work in that case. > > I built parisc generic-{32,64}bit_defconfig with DYNAMIC_FTRACE enabled, > and verified that the section made it into the .ko files for modules. This is because of remaining #ifdeffery in include/asm-generic/vmlinux.lds.h: #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY #define MCOUNT_REC() . = ALIGN(8); \ __start_mcount_loc = .; \ KEEP(*(__patchable_function_entries)) \ __stop_mcount_loc = .; #else #define MCOUNT_REC() . = ALIGN(8); \ __start_mcount_loc = .; \ KEEP(*(__mcount_loc)) \ __stop_mcount_loc = .; #endif Maybe you want to tackle that as well? I suggest to have at least one FTRACE_CALLSITE_SECTION definition without double quotes. Alternatively, my earlier solution just kept both sections, in case either one or both are present. KEEP(*(__patchable_function_entries)) \ KEEP(*(__mcount_loc)) \ Torsten