Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756189AbZLWV0R (ORCPT ); Wed, 23 Dec 2009 16:26:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756323AbZLWVUs (ORCPT ); Wed, 23 Dec 2009 16:20:48 -0500 Received: from mail.windriver.com ([147.11.1.11]:45132 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756189AbZLWVUq (ORCPT ); Wed, 23 Dec 2009 16:20:46 -0500 From: Jason Wessel To: linux-kernel@vger.kernel.org Cc: kgdb-bugreport@lists.sourceforge.net, kdb@oss.sgi.com, mingo@elte.hu, Jason Wessel Subject: [PATCH 23/37] kgdb: Add the ability to schedule a breakpoint via a tasklet Date: Wed, 23 Dec 2009 15:19:36 -0600 Message-Id: <1261603190-5036-24-git-send-email-jason.wessel@windriver.com> X-Mailer: git-send-email 1.6.4.rc1 In-Reply-To: <1261603190-5036-23-git-send-email-jason.wessel@windriver.com> References: <1261603190-5036-1-git-send-email-jason.wessel@windriver.com> <1261603190-5036-2-git-send-email-jason.wessel@windriver.com> <1261603190-5036-3-git-send-email-jason.wessel@windriver.com> <1261603190-5036-4-git-send-email-jason.wessel@windriver.com> <1261603190-5036-5-git-send-email-jason.wessel@windriver.com> <1261603190-5036-6-git-send-email-jason.wessel@windriver.com> <1261603190-5036-7-git-send-email-jason.wessel@windriver.com> <1261603190-5036-8-git-send-email-jason.wessel@windriver.com> <1261603190-5036-9-git-send-email-jason.wessel@windriver.com> <1261603190-5036-10-git-send-email-jason.wessel@windriver.com> <1261603190-5036-11-git-send-email-jason.wessel@windriver.com> <1261603190-5036-12-git-send-email-jason.wessel@windriver.com> <1261603190-5036-13-git-send-email-jason.wessel@windriver.com> <1261603190-5036-14-git-send-email-jason.wessel@windriver.com> <1261603190-5036-15-git-send-email-jason.wessel@windriver.com> <1261603190-5036-16-git-send-email-jason.wessel@windriver.com> <1261603190-5036-17-git-send-email-jason.wessel@windriver.com> <1261603190-5036-18-git-send-email-jason.wessel@windriver.com> <1261603190-5036-19-git-send-email-jason.wessel@windriver.com> <1261603190-5036-20-git-send-email-jason.wessel@windriver.com> <1261603190-5036-21-git-send-email-jason.wessel@windriver.com> <1261603190-5036-22-git-send-email-jason.wessel@windriver.com> <1261603190-5036-23-git-send-email-jason.wessel@windriver.com> X-OriginalArrivalTime: 23 Dec 2009 21:20:23.0536 (UTC) FILETIME=[BD1B8F00:01CA8415] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2654 Lines: 78 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. This is true of some of the kgdb I/O drivers which share code with kgdb and rest of the kernel users. Signed-off-by: Jason Wessel --- include/linux/kgdb.h | 1 + kernel/debug/debug_core.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 0 deletions(-) diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index f46d466..b5de457 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -303,6 +303,7 @@ extern int kgdb_nmicallback(int cpu, void *regs); 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/debug/debug_core.c b/kernel/debug/debug_core.c index 06e73e0..e44e693 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -112,6 +112,7 @@ 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; @@ -777,6 +778,31 @@ 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; -- 1.6.4.rc1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/