From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 81605 invoked by alias); 23 Feb 2016 02:00:46 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 81327 invoked by uid 89); 23 Feb 2016 02:00:44 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=cell, Cell, watchpoint X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 23 Feb 2016 02:00:43 +0000 Received: from svr-orw-fem-03.mgc.mentorg.com ([147.34.97.39]) by relay1.mentorg.com with esmtp id 1aY2HH-0005yd-Bb from Luis_Gustavo@mentor.com ; Mon, 22 Feb 2016 18:00:39 -0800 Received: from [172.30.1.130] (147.34.91.1) by svr-orw-fem-03.mgc.mentorg.com (147.34.97.39) with Microsoft SMTP Server id 14.3.224.2; Mon, 22 Feb 2016 18:00:38 -0800 Reply-To: Luis Machado Subject: Re: [PATCH, v3] Expect SI_KERNEL or TRAP_BRKPT si_code values for MIPS breakpoint traps References: <1456179628-14249-1-git-send-email-lgustavo@codesourcery.com> <56CB8E9D.70605@redhat.com> To: Pedro Alves , CC: From: Luis Machado Message-ID: <56CBBD44.8020808@codesourcery.com> Date: Tue, 23 Feb 2016 02:00:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <56CB8E9D.70605@redhat.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2016-02/txt/msg00676.txt.bz2 On 02/22/2016 07:41 PM, Pedro Alves wrote: > On 02/22/2016 10:20 PM, Luis Machado wrote: > >> diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h >> index ba58717..72b32b1 100644 >> --- a/gdb/nat/linux-ptrace.h >> +++ b/gdb/nat/linux-ptrace.h >> @@ -140,11 +140,16 @@ struct buffer; >> in SPU code on a Cell/B.E. However, SI_KERNEL is never seen >> on a SIGTRAP for any other reason. >> >> + The MIPS kernel uses the default si_code of SI_KERNEL for software >> + breakpoints, hardware watchpoints and SIGTRAP's in general. > > If we get this for both software breakpoints and hardware watchpoints, > then it seems to me that this change still leaves watchpoints broken, > as I can't see how check_stopped_by_watchpoint is reached, in either > gdb/linux-nat.c or gdbserver/linux-low.c. With or without this specific breakpoint fix, hardware watchpoints are already broken for MIPS AFAICS. MIPS' kernel has never set si_code to anything other than SI_KERNEL. When the change to expect TRAP_HWBKPT was committed, then hardware watchpoints stopped working properly for MIPS. Now all hardware watchpoints produce are breakpoint-like traps that get silently ignored by GDB as "delayed software breakpoint trap". Neither GDB nor GDBserver can tell when a hardware watchpoint really happened by using si_code information. But this seems to be a different issue and i think it should be handle separately. > > Also, "and SIGTRAP's in general." seems wrong. I hope that that's > not the case for user-sent SIGTRAPs? > I'll get this updated in the next version.