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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B8FFBC43381 for ; Tue, 5 Mar 2019 00:22:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DAC220684 for ; Tue, 5 Mar 2019 00:22:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726865AbfCEAWE (ORCPT ); Mon, 4 Mar 2019 19:22:04 -0500 Received: from 59-120-53-16.HINET-IP.hinet.net ([59.120.53.16]:28879 "EHLO ATCSQR.andestech.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726066AbfCEAWE (ORCPT ); Mon, 4 Mar 2019 19:22:04 -0500 Received: from mail.andestech.com (atcpcs16.andestech.com [10.0.1.222]) by ATCSQR.andestech.com with ESMTP id x250KMj2014854; Tue, 5 Mar 2019 08:20:22 +0800 (GMT-8) (envelope-from vincentc@andestech.com) Received: from andestech.com (10.0.15.65) by ATCPCS16.andestech.com (10.0.1.222) with Microsoft SMTP Server id 14.3.123.3; Tue, 5 Mar 2019 08:21:20 +0800 Date: Tue, 5 Mar 2019 08:21:17 +0800 From: Vincent Chen To: Palmer Dabbelt CC: "aou@eecs.berkeley.edu" , "ebiederm@xmission.com" , Jim Wilson , Arnd Bergmann , "linux-riscv@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "deanbo422@gmail.com" Subject: Re: [PATCH 0/3] riscv: Fix debug instruction check and support trap-based WARN() Message-ID: <20190305002116.GA5887@andestech.com> References: <1551349891-22683-1-git-send-email-vincentc@andestech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Originating-IP: [10.0.15.65] X-DNSRBL: X-MAIL: ATCSQR.andestech.com x250KMj2014854 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 05, 2019 at 04:35:08AM +0800, Palmer Dabbelt wrote: > On Thu, 28 Feb 2019 02:31:28 PST (-0800), vincentc@andestech.com wrote: > > The handler for the debug exception will call is_valid_bugaddr(bugaddr) to > > check if the instruction in bugaddr is a real debug instruction. However, > > the expected instruction, ebreak, is possibly translated to c.ebreak by > > assmebler when C extension is supported. This patchset will add c.ebreak > > into the check mechanism. In addition, BUG() is currently unable to work in > > the kernel module due to an inappropriated condition in is_valid_bugaddr(). > > This issue will be fixed in this patchset. Finally, this patchset enables > > WARN() related functions to trap the code to help developers debug it. > > > > > > > > > > > > Vincent Chen (3): > > riscv: Add the support for c.ebreak check in is_valid_bugaddr() > > riscv: Support BUG() in kernel module > > riscv: Make WARN() related functions able to trigger a trap exception > > I'm finding this patch set a bit hard to follow, and I think it has more diff > than is necessary. For example, the first patch introduces a new die() only to > have it removed by the third patch. There's also some unnecessary > non-functional diff, like > > @@ -149,12 +161,13 @@ int is_valid_bugaddr(unsigned long pc) > if (probe_kernel_address((bug_insn_t *)pc, insn)) > return 0; > if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) > - return insn == __BUG_INSN_32; > + return (insn == __BUG_INSN_32); > else > - return (insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16; > + return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); > } > #endif /* CONFIG_GENERIC_BUG */ > > + > void __init trap_init(void) > { > /* > > I like the idea of the patch set, though. Do you have time to clean it up and > submit a v2? OK, I will improve it and submit a v2 patch.