From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757816Ab0BLWgq (ORCPT ); Fri, 12 Feb 2010 17:36:46 -0500 Received: from mail.windriver.com ([147.11.1.11]:44142 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757739Ab0BLWgj (ORCPT ); Fri, 12 Feb 2010 17:36:39 -0500 From: Jason Wessel To: linux-kernel@vger.kernel.org Cc: kgdb-bugreport@lists.sourceforge.net, mingo@elte.hu, Jason Wessel Subject: [PATCH 20/28] kgdb: Add the ability to schedule a breakpoint via a tasklet Date: Fri, 12 Feb 2010 16:35:35 -0600 Message-Id: <1266014143-29444-21-git-send-email-jason.wessel@windriver.com> X-Mailer: git-send-email 1.6.4.rc1 In-Reply-To: <1266014143-29444-1-git-send-email-jason.wessel@windriver.com> References: <1266014143-29444-1-git-send-email-jason.wessel@windriver.com> X-OriginalArrivalTime: 12 Feb 2010 22:36:21.0583 (UTC) FILETIME=[CCFB95F0:01CAAC33] 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. 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 19d1b29..ee007ea 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -271,6 +271,7 @@ extern int kgdb_mem2hex(char *mem, char *buf, int count); extern int kgdb_hex2mem(char *buf, char *mem, int count); extern int kgdb_isremovedbreak(unsigned long addr); +extern void kgdb_schedule_breakpoint(void); extern int kgdb_handle_exception(int ex_vector, int signo, int err_code, diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 8db8e40..ef46af3 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -114,6 +114,7 @@ EXPORT_SYMBOL_GPL(kgdb_active); */ 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; @@ -781,6 +782,31 @@ 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