tracing: Add syscall tracepoints

[pandora-kernel.git] / kernel / tracepoint.c

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 1ef5d3a..070a42b 100644 (file)
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -24,6 +24,7 @@
 #include <linux/tracepoint.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <linux/sched.h>
 
 extern struct tracepoint __start___tracepoints[];
 extern struct tracepoint __stop___tracepoints[];
@@ -577,3 +578,40 @@ static int init_tracepoints(void)
 __initcall(init_tracepoints);
 
 #endif /* CONFIG_MODULES */
+
+static DEFINE_MUTEX(regfunc_mutex);
+static int sys_tracepoint_refcount;
+
+void syscall_regfunc(void)
+{
+       unsigned long flags;
+       struct task_struct *g, *t;
+
+       mutex_lock(&regfunc_mutex);
+       if (!sys_tracepoint_refcount) {
+               read_lock_irqsave(&tasklist_lock, flags);
+               do_each_thread(g, t) {
+                       set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
+               } while_each_thread(g, t);
+               read_unlock_irqrestore(&tasklist_lock, flags);
+       }
+       sys_tracepoint_refcount++;
+       mutex_unlock(&regfunc_mutex);
+}
+
+void syscall_unregfunc(void)
+{
+       unsigned long flags;
+       struct task_struct *g, *t;
+
+       mutex_lock(&regfunc_mutex);
+       sys_tracepoint_refcount--;
+       if (!sys_tracepoint_refcount) {
+               read_lock_irqsave(&tasklist_lock, flags);
+               do_each_thread(g, t) {
+                       clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
+               } while_each_thread(g, t);
+               read_unlock_irqrestore(&tasklist_lock, flags);
+       }
+       mutex_unlock(&regfunc_mutex);
+}