From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755564AbYJUTP0 (ORCPT ); Tue, 21 Oct 2008 15:15:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754637AbYJUTPH (ORCPT ); Tue, 21 Oct 2008 15:15:07 -0400 Received: from mail.windriver.com ([147.11.1.11]:44621 "EHLO mail.wrs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755524AbYJUTPE (ORCPT ); Tue, 21 Oct 2008 15:15:04 -0400 From: Jason Wessel To: kgdb-bugreport@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org, Jason Wessel Subject: [PATCH 1/7] kgdb: Add the ability to schedule a breakpoint via a tasklet Date: Tue, 21 Oct 2008 14:14:47 -0500 Message-Id: <1224616493-23237-2-git-send-email-jason.wessel@windriver.com> X-Mailer: git-send-email 1.6.0.2 In-Reply-To: <1224616493-23237-1-git-send-email-jason.wessel@windriver.com> References: <1224616493-23237-1-git-send-email-jason.wessel@windriver.com> X-OriginalArrivalTime: 21 Oct 2008 19:14:54.0810 (UTC) FILETIME=[4CD623A0:01C933B1] 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 6adcc29..8fdd3cb 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -279,5 +279,6 @@ extern int kgdb_nmicallback(int cpu, void *regs); extern int kgdb_single_step; extern atomic_t kgdb_active; +extern void kgdb_schedule_breakpoint(void); #endif /* _KGDB_H_ */ diff --git a/kernel/kgdb.c b/kernel/kgdb.c index e4dcfb2..5365d46 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -123,6 +123,7 @@ 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; @@ -1623,6 +1624,31 @@ static void kgdb_unregister_callbacks(void) } } +/* + * There are times a tasklet needs to be used vs a compiled in 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; -- 1.6.0.2