context_tracking: Move exception handling to generic code

Exceptions handling on context tracking should share common
treatment: on entry we exit user mode if the exception triggered
in that context. Then on exception exit we return to that previous
context.

Generalize this to avoid duplication across archs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Mats Liljegren <mats.liljegren@enea.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index b28d161c1091..5a69273e93e6 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -1,10 +1,11 @@
 #ifndef _LINUX_CONTEXT_TRACKING_H
 #define _LINUX_CONTEXT_TRACKING_H
 
-#ifdef CONFIG_CONTEXT_TRACKING
 #include <linux/sched.h>
 #include <linux/percpu.h>
+#include <asm/ptrace.h>
 
+#ifdef CONFIG_CONTEXT_TRACKING
 struct context_tracking {
         /*
          * When active is false, probes are unset in order
@@ -33,12 +34,26 @@ static inline bool context_tracking_active(void)
 
 extern void user_enter(void);
 extern void user_exit(void);
+
+static inline void exception_enter(struct pt_regs *regs)
+{
+        user_exit();
+}
+
+static inline void exception_exit(struct pt_regs *regs)
+{
+        if (user_mode(regs))
+                user_enter();
+}
+
 extern void context_tracking_task_switch(struct task_struct *prev,
                                          struct task_struct *next);
 #else
 static inline bool context_tracking_in_user(void) { return false; }
 static inline void user_enter(void) { }
 static inline void user_exit(void) { }
+static inline void exception_enter(struct pt_regs *regs) { }
+static inline void exception_exit(struct pt_regs *regs) { }
 static inline void context_tracking_task_switch(struct task_struct *prev,
                                                 struct task_struct *next) { }
 #endif /* !CONFIG_CONTEXT_TRACKING */