arm: Fix build error with context tracking calls

ad65782fba50 (context_tracking: Optimize main APIs off case
with static key) converted context tracking main APIs to inline
function and left ARM asm callers behind.

This can be easily fixed by making ARM calling the post static
keys context tracking function. We just need to replicate the
static key checks there. We'll remove these later when ARM will
support the context tracking static keys.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Anil Kumar <anilk4.v@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Kevin Hilman <khilman@linaro.org>

2 files changed, 16 insertions, 4 deletions

diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index de23a9beed13..39f89fbd5111 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -329,10 +329,10 @@
 #ifdef CONFIG_CONTEXT_TRACKING
         .if     \save
         stmdb   sp!, {r0-r3, ip, lr}
-        bl      user_exit
+        bl      context_tracking_user_exit
         ldmia   sp!, {r0-r3, ip, lr}
         .else
-        bl      user_exit
+        bl      context_tracking_user_exit
         .endif
 #endif
         .endm
@@ -341,10 +341,10 @@
 #ifdef CONFIG_CONTEXT_TRACKING
         .if     \save
         stmdb   sp!, {r0-r3, ip, lr}
-        bl      user_enter
+        bl      context_tracking_user_enter
         ldmia   sp!, {r0-r3, ip, lr}
         .else
-        bl      user_enter
+        bl      context_tracking_user_enter
         .endif
 #endif
         .endm
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 247091bf0587..859c8dfd78a1 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -51,6 +51,15 @@ void context_tracking_user_enter(void)
         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 static key
+         * check.
+         */
+        if (!static_key_false(&context_tracking_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()
@@ -151,6 +160,9 @@ void context_tracking_user_exit(void)
 {
         unsigned long flags;
 
+        if (!static_key_false(&context_tracking_enabled))
+                return;
+
         if (in_interrupt())
                 return;