From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26861 invoked by alias); 9 Jun 2011 13:10:05 -0000 Received: (qmail 26484 invoked by uid 22791); 9 Jun 2011 13:10:04 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,TW_XF,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 09 Jun 2011 13:09:50 +0000 Received: (qmail 6769 invoked from network); 9 Jun 2011 13:09:49 -0000 Received: from unknown (HELO ?192.168.0.102?) (yao@127.0.0.2) by mail.codesourcery.com with ESMTPA; 9 Jun 2011 13:09:49 -0000 Message-ID: <4DF0C613.70101@codesourcery.com> Date: Thu, 09 Jun 2011 13:10:00 -0000 From: Yao Qi User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110424 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: Mark Kettenis CC: gdb-patches@sourceware.org Subject: Re: [patch, testsuite] gdb.base/savedregs.exp: SIGSEGV -> SIGILL References: <4DF09229.4070704@codesourcery.com> <201106091117.p59BHRWi025356@glazunov.sibelius.xs4all.nl> In-Reply-To: <201106091117.p59BHRWi025356@glazunov.sibelius.xs4all.nl> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-IsSubscribed: yes 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 X-SW-Source: 2011-06/txt/msg00129.txt.bz2 On 06/09/2011 07:17 PM, Mark Kettenis wrote: >> Date: Thu, 09 Jun 2011 17:28:09 +0800 >> From: Yao Qi >> >> In current gdb.base/savedregs.exp, signal handler is installed for >> signal SIGSEGV, and SIGSEGV is trigger by `*(char *)0 = 0;'. However, >> on non-mmu uclinux system, writing to an address 0x0 doesn't trigger >> SIGSEGV. >> >> In my patch, SIGILL is chosen to replace SIGSEGV. One assumption here >> is that 0xffff is an invalid instruction on all ports. > > Please don't do this. You're changing the test significantly. And I don't think the test is changed *significantly*. The purpose of writing to zero, at least in this case, is to trigger a signal, and check the register in signal trampoline frame. Either SIGSEGV or SIGILL meets this need. > there is no guarantee that 0xffff is an invalid instruction. Heck > most platforms don't even have 16-bit instructions. It is possible to find a `common' invalid instruction over all ports, even 0xffff may not be. -- Yao (齐尧)