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=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 851F1C433E0 for ; Wed, 10 Mar 2021 08:18:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49E1964FDE for ; Wed, 10 Mar 2021 08:18:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231278AbhCJISO (ORCPT ); Wed, 10 Mar 2021 03:18:14 -0500 Received: from mx2.suse.de ([195.135.220.15]:58982 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229900AbhCJISI (ORCPT ); Wed, 10 Mar 2021 03:18:08 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D3C81AC1F; Wed, 10 Mar 2021 08:18:06 +0000 (UTC) Date: Wed, 10 Mar 2021 09:18:06 +0100 (CET) From: Miroslav Benes To: Jinyang He cc: Thomas Bogendoerfer , Tiezhu Yang , Xuefeng Li , linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org Subject: Re: [PATCH RFC] MIPS: livepatch: Add LIVEPATCH basic code In-Reply-To: <1614598201-17858-1-git-send-email-hejinyang@loongson.cn> Message-ID: References: <1614598201-17858-1-git-send-email-hejinyang@loongson.cn> 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: live-patching@vger.kernel.org Hi, I cannot really comment on mips arch specifics but few words from the live patching perspective. On Mon, 1 Mar 2021, Jinyang He wrote: > Add the basic code of livepatch. livepatch is temporarily unavailable. > Two core functions are missing, one is DYNAMIC_FTRACE_WITH_REGS, and > another is save_stack_trace_tsk_reliable(). > `Huang Pei ` is doing for ftrace. He will use > `-fpatchable-function-entry` to achieve more complete ftrace. DYNAMIC_FTRACE_WITH_ARGS has been introduced recently, so you might also look at that. As far as the live patching is concerned, DYNAMIC_FTRACE_WITH_ARGS is sufficient. > save_stack_trace_tsk_reliable() currently has difficulties. This function > may be improved in the future, but that seems to be a long time away. > This is also the reason for delivering this RFC. Hope to get any help. You may want to look at Documentation/livepatch/reliable-stacktrace.rst which nicely describes the requirements for the reliable stacktraces. Regards Miroslav