X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=kernel%2Fcontext_tracking.c;h=d8560ee3bab788c15be6d1be8eb610473fc5c4b5;hb=85e7a1d463badc2813b7fdac50942517674015ba;hp=0a495ab35bc72b55d8eab13f0922e6fdb8099d9a;hpb=d7b273685fedba5359a4ba0ae4f542e3ece28153;p=firefly-linux-kernel-4.4.55.git

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 0a495ab35bc7..d8560ee3bab7 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -58,36 +58,13 @@ static void context_tracking_recursion_exit(void)
  * instructions to execute won't use any RCU read side critical section
  * because this function sets RCU in extended quiescent state.
  */
-void context_tracking_enter(enum ctx_state state)
+void __context_tracking_enter(enum ctx_state state)
 {
-	unsigned long flags;
-
-	/*
-	 * Repeat the user_enter() check here because some archs may be calling
-	 * this from asm and if no CPU needs context tracking, they shouldn't
-	 * go further. Repeat the check here until they support the inline static
-	 * key check.
-	 */
-	if (!context_tracking_is_enabled())
-		return;
-
-	/*
-	 * Some contexts may involve an exception occuring in an irq,
-	 * leading to that nesting:
-	 * rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit()
-	 * This would mess up the dyntick_nesting count though. And rcu_irq_*()
-	 * helpers are enough to protect RCU uses inside the exception. So
-	 * just return immediately if we detect we are in an IRQ.
-	 */
-	if (in_interrupt())
-		return;
-
 	/* Kernel threads aren't supposed to go to userspace */
 	WARN_ON_ONCE(!current->mm);
 
-	local_irq_save(flags);
 	if (!context_tracking_recursion_enter())
-		goto out_irq_restore;
+		return;
 
 	if ( __this_cpu_read(context_tracking.state) != state) {
 		if (__this_cpu_read(context_tracking.active)) {
@@ -120,7 +97,27 @@ void context_tracking_enter(enum ctx_state state)
 		__this_cpu_write(context_tracking.state, state);
 	}
 	context_tracking_recursion_exit();
-out_irq_restore:
+}
+NOKPROBE_SYMBOL(__context_tracking_enter);
+EXPORT_SYMBOL_GPL(__context_tracking_enter);
+
+void context_tracking_enter(enum ctx_state state)
+{
+	unsigned long flags;
+
+	/*
+	 * Some contexts may involve an exception occuring in an irq,
+	 * leading to that nesting:
+	 * rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit()
+	 * This would mess up the dyntick_nesting count though. And rcu_irq_*()
+	 * helpers are enough to protect RCU uses inside the exception. So
+	 * just return immediately if we detect we are in an IRQ.
+	 */
+	if (in_interrupt())
+		return;
+
+	local_irq_save(flags);
+	__context_tracking_enter(state);
 	local_irq_restore(flags);
 }
 NOKPROBE_SYMBOL(context_tracking_enter);
@@ -128,7 +125,7 @@ EXPORT_SYMBOL_GPL(context_tracking_enter);
 
 void context_tracking_user_enter(void)
 {
-	context_tracking_enter(CONTEXT_USER);
+	user_enter();
 }
 NOKPROBE_SYMBOL(context_tracking_user_enter);
 
@@ -144,19 +141,10 @@ NOKPROBE_SYMBOL(context_tracking_user_enter);
  * This call supports re-entrancy. This way it can be called from any exception
  * handler without needing to know if we came from userspace or not.
  */
-void context_tracking_exit(enum ctx_state state)
+void __context_tracking_exit(enum ctx_state state)
 {
-	unsigned long flags;
-
-	if (!context_tracking_is_enabled())
-		return;
-
-	if (in_interrupt())
-		return;
-
-	local_irq_save(flags);
 	if (!context_tracking_recursion_enter())
-		goto out_irq_restore;
+		return;
 
 	if (__this_cpu_read(context_tracking.state) == state) {
 		if (__this_cpu_read(context_tracking.active)) {
@@ -173,7 +161,19 @@ void context_tracking_exit(enum ctx_state state)
 		__this_cpu_write(context_tracking.state, CONTEXT_KERNEL);
 	}
 	context_tracking_recursion_exit();
-out_irq_restore:
+}
+NOKPROBE_SYMBOL(__context_tracking_exit);
+EXPORT_SYMBOL_GPL(__context_tracking_exit);
+
+void context_tracking_exit(enum ctx_state state)
+{
+	unsigned long flags;
+
+	if (in_interrupt())
+		return;
+
+	local_irq_save(flags);
+	__context_tracking_exit(state);
 	local_irq_restore(flags);
 }
 NOKPROBE_SYMBOL(context_tracking_exit);
@@ -181,7 +181,7 @@ EXPORT_SYMBOL_GPL(context_tracking_exit);
 
 void context_tracking_user_exit(void)
 {
-	context_tracking_exit(CONTEXT_USER);
+	user_exit();
 }
 NOKPROBE_SYMBOL(context_tracking_user_exit);