[S390] implement is_compat_task

Implement is_compat_task and use it all over the place.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index de065b32381..01a08020bc0 100644
--- a/arch/s390/include/asm/compat.h
+++ b/arch/s390/include/asm/compat.h
@@ -5,6 +5,7 @@
  */
 #include <linux/types.h>
 #include <linux/sched.h>
+#include <linux/thread_info.h>
 
 #define PSW32_MASK_PER		0x40000000UL
 #define PSW32_MASK_DAT		0x04000000UL
@@ -163,12 +164,28 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
 	return (u32)(unsigned long)uptr;
 }
 
+#ifdef CONFIG_COMPAT
+
+static inline int is_compat_task(void)
+{
+	return test_thread_flag(TIF_31BIT);
+}
+
+#else
+
+static inline int is_compat_task(void)
+{
+	return 0;
+}
+
+#endif
+
 static inline void __user *compat_alloc_user_space(long len)
 {
 	unsigned long stack;
 
 	stack = KSTK_ESP(current);
-	if (test_thread_flag(TIF_31BIT))
+	if (is_compat_task())
 		stack &= 0x7fffffffUL;
 	return (void __user *) (stack - len);
 }