kgdb: Add the ability to schedule a breakpoint via a tasklet

[safe/jmp/linux-2.6] / kernel / debug / debug_core.c

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 375e42f..fff5901 100644 (file)
--- 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;
@@ -789,6 +790,31 @@ 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;