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-rw-r--r--kernel/tracepoint.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 1ef5d3a601c..070a42bb892 100644
--- 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);
+}