From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764654AbZEHV17 (ORCPT ); Fri, 8 May 2009 17:27:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761057AbZEHVXv (ORCPT ); Fri, 8 May 2009 17:23:51 -0400 Received: from mail.windriver.com ([147.11.1.11]:44769 "EHLO mail.wrs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757970AbZEHVXh (ORCPT ); Fri, 8 May 2009 17:23:37 -0400 From: Jason Wessel To: linux-kernel@vger.kernel.org Cc: kgdb-bugreport@lists.sourceforge.net, kdb@oss.sgi.com, Jason Wessel Subject: [PATCH 11/13] kgdb: Add the ability to schedule a breakpoint via a tasklet Date: Fri, 8 May 2009 16:23:18 -0500 Message-Id: <1241817800-9320-12-git-send-email-jason.wessel@windriver.com> X-Mailer: git-send-email 1.6.3.rc0.1.gf800 In-Reply-To: <1241817800-9320-11-git-send-email-jason.wessel@windriver.com> References: <1241817800-9320-1-git-send-email-jason.wessel@windriver.com> <1241817800-9320-2-git-send-email-jason.wessel@windriver.com> <1241817800-9320-3-git-send-email-jason.wessel@windriver.com> <1241817800-9320-4-git-send-email-jason.wessel@windriver.com> <1241817800-9320-5-git-send-email-jason.wessel@windriver.com> <1241817800-9320-6-git-send-email-jason.wessel@windriver.com> <1241817800-9320-7-git-send-email-jason.wessel@windriver.com> <1241817800-9320-8-git-send-email-jason.wessel@windriver.com> <1241817800-9320-9-git-send-email-jason.wessel@windriver.com> <1241817800-9320-10-git-send-email-jason.wessel@windriver.com> <1241817800-9320-11-git-send-email-jason.wessel@windriver.com> X-OriginalArrivalTime: 08 May 2009 21:23:32.0513 (UTC) FILETIME=[3D266910:01C9D023] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some kgdb I/O modules require the ability to create a breakpoint tasklet, such as kgdboc and external modules such as kgdboe. The breakpoint tasklet is used as an asynchronous entry point into the debugger which will have a different function scope than the current execution path where it might not be safe to have an inline breakpoint inside the kgdb I/O driver. Signed-off-by: Jason Wessel --- include/linux/kgdb.h | 1 + kernel/kgdb.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 0 deletions(-) diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index 166cd07..1fa0bcc 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -270,6 +270,7 @@ extern int kgdb_use_passthrough; extern void kgdb_msg_write(const char *s, int len); extern int kgdb_single_step; extern atomic_t kgdb_active; +extern void kgdb_schedule_breakpoint(void); #ifdef CONFIG_KGDB_SERIAL_CONSOLE extern void __init early_kgdboc_init(void); diff --git a/kernel/kgdb.c b/kernel/kgdb.c index da738a2..f303410 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -136,6 +136,7 @@ atomic_t kgdb_active = ATOMIC_INIT(-1); */ static atomic_t passive_cpu_wait[NR_CPUS]; static atomic_t cpu_in_kgdb[NR_CPUS]; +static atomic_t kgdb_break_tasklet_var; atomic_t kgdb_setting_breakpoint; struct task_struct *kgdb_usethread; @@ -1862,6 +1863,31 @@ static void kgdb_unregister_callbacks(void) } } +/* + * There are times a tasklet needs to be used vs a compiled in + * break point so as to cause an exception outside a kgdb I/O module, + * such as is the case with kgdboe, where calling a breakpoint in the + * I/O driver itself would be fatal. + */ +static void kgdb_tasklet_bpt(unsigned long ing) +{ + kgdb_breakpoint(); + atomic_set(&kgdb_break_tasklet_var, 0); +} + +static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0); + +void kgdb_schedule_breakpoint(void) +{ + if (atomic_read(&kgdb_break_tasklet_var) || + atomic_read(&kgdb_active) != -1 || + atomic_read(&kgdb_setting_breakpoint)) + return; + atomic_inc(&kgdb_break_tasklet_var); + tasklet_schedule(&kgdb_tasklet_breakpoint); +} +EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint); + static void kgdb_initial_breakpoint(void) { kgdb_break_asap = 0; -- 1.6.3.rc0.1.gf800