s390/uaccess: avoid mvcos jump label

If the kernel is compiled for z10 or later machines the uaccess
code inlines the mvcos instruction. The facility bit 27 which
indicates the availability of MVCOS has to be set. The have_mvcos
jump label will always be true.

Make the generation of the have_mvcos jump label conditional on
!CONFIG_HAVE_MARCH_Z10_FEATURES.

Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/lib/uaccess.c

···
 #include <asm/mmu_context.h>
 #include <asm/facility.h>
 
+#ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
+
+static int __init uaccess_init(void)
+{
+	if (test_facility(27))
+		static_branch_enable(&have_mvcos);
+	return 0;
+}
+early_initcall(uaccess_init);
+
+static inline int copy_with_mvcos(void)
+{
+	if (static_branch_likely(&have_mvcos))
+		return 1;
+	return 0;
+}
+#else
+static inline int copy_with_mvcos(void)
+{
+	return 1;
+}
+#endif
 
 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
 						 unsigned long size)
···
 
 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 		return copy_from_user_mvcos(to, from, n);
 	return copy_from_user_mvcp(to, from, n);
 }
···
 
 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 		return copy_to_user_mvcos(to, from, n);
 	return copy_to_user_mvcs(to, from, n);
 }
···
 
 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 		return copy_in_user_mvcos(to, from, n);
 	return copy_in_user_mvc(to, from, n);
 }
···
 
 unsigned long __clear_user(void __user *to, unsigned long size)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 			return clear_user_mvcos(to, size);
 	return clear_user_xc(to, size);
 }
···
 	return done;
 }
 EXPORT_SYMBOL(__strncpy_from_user);
-
-static int __init uaccess_init(void)
-{
-	if (test_facility(27))
-		static_branch_enable(&have_mvcos);
-	return 0;
-}
-early_initcall(uaccess_init);