From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e1.ny.us.ibm.com (e1.ny.us.ibm.com [32.97.182.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e1.ny.us.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 8EDBC2C00D0 for ; Mon, 5 Nov 2012 19:16:02 +1100 (EST) Received: from /spool/local by e1.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 5 Nov 2012 03:15:58 -0500 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id DF9BB38C8026 for ; Mon, 5 Nov 2012 03:15:34 -0500 (EST) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id qA58FYst285222 for ; Mon, 5 Nov 2012 03:15:34 -0500 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id qA58FX12005614 for ; Mon, 5 Nov 2012 01:15:33 -0700 Subject: [PATCH] Enable hardware breakpoint upon re-registering To: linuxppc-dev@ozlabs.org, mikey@neuling.org, linux-kernel@vger.kernel.org, fweisbec@redhat.com, benh@kernel.crashing.org From: Aravinda Prasad Date: Mon, 05 Nov 2012 13:45:28 +0530 Message-ID: <20121105081527.29141.11384.stgit@aravinda> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On powerpc, ptrace will disable hardware breakpoint request once the breakpoint is hit. It is the responsibility of the caller to set it again. However, when the caller sets the hardware breakpoint again using ptrace(PTRACE_SET_DEBUGREG, child_pid, 0, addr), the hardware breakpoint is not enabled. While gdb's approach is to unregister and re-register the hardware breakpoint every time the breakpoint is hit - which is working fine, this could affect other programs trying to re-register hardware breakpoint without unregistering. This patch enables hardware breakpoint if the caller is re-registering. Signed-off-by: Aravinda Prasad --- arch/powerpc/kernel/ptrace.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index 79d8e56..09371d0 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -952,6 +952,10 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, arch_bp_generic_fields(data & (DABR_DATA_WRITE | DABR_DATA_READ), &attr.bp_type); + + /* Enable breakpoint */ + attr.disabled = false; + ret = modify_user_hw_breakpoint(bp, &attr); if (ret) { ptrace_put_breakpoints(task);