Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BDBAC433FE for ; Wed, 22 Dec 2021 14:19:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245662AbhLVOTX (ORCPT ); Wed, 22 Dec 2021 09:19:23 -0500 Received: from smtp-out1.suse.de ([195.135.220.28]:50806 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245647AbhLVOTW (ORCPT ); Wed, 22 Dec 2021 09:19:22 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id DE13B212B9; Wed, 22 Dec 2021 14:19:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1640182760; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Zhr+Afm9qhm7LXnYhc731sR+IngmPtrNRK+NJVmgKNs=; b=xdk2jG0G0otlY+ZrBepZfL4FsYG+3amHldl6XT78E5OMXDCNt53VlsY/4KCA2iGJUbdyPb bKqXHEwQ1EMHkmMnofxOOyioayEurrupL+l/HHXnzXaTjI+TCZMo25//m8HN1si2ctz4fS anZS9KfAh5j3XE8d19HruXGvd6xixaw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1640182760; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Zhr+Afm9qhm7LXnYhc731sR+IngmPtrNRK+NJVmgKNs=; b=Ke6NY5LDOqwezFEELCgm1wBttjIxKixV5PSmi3L6yOjKJMWiWNgKI0WPgaKRDjitu9dis3 DH3vhMXF23LHzxDw== Received: from pobox.suse.cz (pobox.suse.cz [10.100.2.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 8B234A3B81; Wed, 22 Dec 2021 14:19:20 +0000 (UTC) Date: Wed, 22 Dec 2021 15:19:20 +0100 (CET) From: Miroslav Benes To: Christophe Leroy cc: Josh Poimboeuf , Jiri Kosina , Petr Mladek , Joe Lawrence , Steven Rostedt , Ingo Molnar , "Naveen N . Rao" , "linux-kernel@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "live-patching@vger.kernel.org" , linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, broonie@kernel.org, madvenka@linux.microsoft.com Subject: Re: [PATCH v2 09/13] powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS In-Reply-To: <5831f711a778fcd6eb51eb5898f1faae4378b35b.1640017960.git.christophe.leroy@csgroup.eu> Message-ID: References: <5831f711a778fcd6eb51eb5898f1faae4378b35b.1640017960.git.christophe.leroy@csgroup.eu> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 20 Dec 2021, Christophe Leroy wrote: > Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS. It accelerates the call > of livepatching. > > Also note that powerpc being the last one to convert to > CONFIG_DYNAMIC_FTRACE_WITH_ARGS, it will now be possible to remove > klp_arch_set_pc() on all architectures. Correct. We could replace it ftrace_instruction_pointer_set() and that is it. In fact, livepatch.h in both arch/x86/include/asm/ and arch/s390/include/asm/ could be removed with that. On the other hand, there is arm64 live patching support being worked on and I am not sure what their plans about DYNAMIC_FTRACE_WITH_ARGS are. The above would make it a prerequisite. Adding CCs... you can find the whole thread at https://lore.kernel.org/all/cover.1640017960.git.christophe.leroy@csgroup.eu/ Miroslav