From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com [202.81.31.142]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp09.au.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 9BC46DDDB2 for ; Fri, 5 Jun 2009 15:15:57 +1000 (EST) Received: from d23relay02.au.ibm.com (d23relay02.au.ibm.com [202.81.31.244]) by e23smtp09.au.ibm.com (8.13.1/8.13.1) with ESMTP id n55FCV5w029715 for ; Sat, 6 Jun 2009 01:12:31 +1000 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay02.au.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n555FqNY868354 for ; Fri, 5 Jun 2009 15:15:52 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n555FpCn002182 for ; Fri, 5 Jun 2009 15:15:52 +1000 Date: Fri, 5 Jun 2009 15:13:45 +1000 From: David Gibson To: "K.Prasad" Subject: Re: [Patch 3/6] Modify ptrace code to use Hardware Breakpoint interfaces Message-ID: <20090605051345.GK2054@yookeroo.seuss> References: <20090603162741.197115376@prasadkr_t60p.in.ibm.com> <20090603163524.GD5197@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20090603163524.GD5197@in.ibm.com> Cc: Michael Neuling , Benjamin Herrenschmidt , linuxppc-dev@ozlabs.org, paulus@samba.org, Alan Stern , Roland McGrath List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Jun 03, 2009 at 10:05:24PM +0530, K.Prasad wrote: > Modify the ptrace code to use the hardware breakpoint interfaces for user-space. > > Signed-off-by: K.Prasad > --- > arch/powerpc/kernel/ptrace.c | 47 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 47 insertions(+) > > Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c > =================================================================== > --- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/ptrace.c > +++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/ptrace.c > @@ -37,6 +37,7 @@ > #include > #include > #include > +#include > > /* > * does not yet catch signals sent when the child dies. > @@ -735,9 +736,26 @@ void user_disable_single_step(struct tas > clear_tsk_thread_flag(task, TIF_SINGLESTEP); > } > > +void ptrace_triggered(struct hw_breakpoint *bp, struct pt_regs *regs) > +{ > + /* > + * Unregister the breakpoint request here since ptrace has defined a > + * one-shot behaviour for breakpoint exceptions in PPC64. > + * The SIGTRAP signal is generated automatically for us in do_dabr(). > + * We don't have to do anything here > + */ > + unregister_user_hw_breakpoint(current, bp); > + kfree(bp); Couldn't you also clear the saved dabr info here, to avoid having to special case this in the actual breakpoint handler. Also, I think you should be delivering the signal here - for gdb compatibility I think we'll need to match the old behaviour which has the TRAP delivered before executing the breakpointed instruction. > +} > + > int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, > unsigned long data) > { > +#ifdef CONFIG_PPC64 > + struct thread_struct *thread = &(task->thread); > + struct hw_breakpoint *bp; > + int ret; > +#endif > /* For ppc64 we support one DABR and no IABR's at the moment (ppc64). > * For embedded processors we support one DAC and no IAC's at the > * moment. > @@ -767,6 +785,35 @@ int ptrace_set_debugreg(struct task_stru > if (data && !(data & DABR_TRANSLATION)) > return -EIO; > > +#ifdef CONFIG_PPC64 > + bp = thread->hbp[0]; > + if (data == 0) { > + if (bp) { > + unregister_user_hw_breakpoint(task, bp); > + kfree(bp); > + } > + return 0; > + } > + > + if (bp) { > + bp->info.type = data & HW_BREAKPOINT_RW; > + task->thread.dabr = bp->info.address = data; > + return modify_user_hw_breakpoint(task, bp); > + } > + bp = kzalloc(sizeof(struct hw_breakpoint), GFP_KERNEL); > + if (!bp) > + return -ENOMEM; > + > + /* Store the type of breakpoint */ > + bp->info.type = data & HW_BREAKPOINT_RW; > + bp->triggered = ptrace_triggered; > + task->thread.dabr = bp->info.address = data; > + > + ret = register_user_hw_breakpoint(task, bp); > + if (ret) > + return ret; > +#endif /* CONFIG_PPC64 */ > + > /* Move contents to the DABR register */ > task->thread.dabr = data; > > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-dev > -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson