From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nathan Froyd Date: Mon, 27 Jul 2009 13:14:08 +0000 Subject: Re: [PATCH 0/5] Message-Id: <20090727131408.GW32566@codesourcery.com> List-Id: References: <1248511217-22681-1-git-send-email-yu.liu@freescale.com> In-Reply-To: <1248511217-22681-1-git-send-email-yu.liu@freescale.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Liu Yu Cc: kvm-ppc@vger.kernel.org, jan.kiszka@siemens.com, qemu-devel@nongnu.org, hollisb@us.ibm.com On Sat, Jul 25, 2009 at 04:40:12PM +0800, Liu Yu wrote: > For example booke has a code template for > jumping to and returning from interrupt handlers: > > bl transfer > .long handler_addr > .long ret_addr > > when call transfer, it never return but > in transfer assembly code it will read the handler_addr > and ultimately call the handler. > Gdb doesn't know that and treat it as a normal function call. > so gdb put a software breakpoint instruction at handler_addr, > in order to get trap there when return from transfer. > > Then guest will read software breakpoint as handler_addr and jump to there.. > > I'm not sure if x86 suffer this kind of issue. > Is there any way to avoid this? You would need to modify GDB to recognize this sort of case with the skip_trampoline_code gdbarch method. -Nathan