1 files changed, 70 insertions, 19 deletions

diff --git a/arch/s390/lib/uaccess_mvcos.c b/arch/s390/lib/uaccess_mvcos.c
index 95123f5..66f35e1 100644
--- a/arch/s390/lib/uaccess_mvcos.c
+++ b/arch/s390/lib/uaccess_mvcos.c
@@ -6,7 +6,9 @@
  *		 Gerald Schaefer (gerald.schaefer@de.ibm.com)
  */
 
+#include <linux/jump_label.h>
 #include <linux/errno.h>
+#include <linux/init.h>
 #include <linux/mm.h>
 #include <asm/uaccess.h>
 #include <asm/futex.h>
@@ -26,7 +28,10 @@
 #define SLR	"slgr"
 #endif
 
-static size_t copy_from_user_mvcos(void *x, const void __user *ptr, size_t size)
+static struct static_key have_mvcos = STATIC_KEY_INIT_TRUE;
+
+static inline size_t copy_from_user_mvcos(void *x, const void __user *ptr,
+					  size_t size)
 {
 	register unsigned long reg0 asm("0") = 0x81UL;
 	unsigned long tmp1, tmp2;
@@ -65,7 +70,16 @@ static size_t copy_from_user_mvcos(void *x, const void __user *ptr, size_t size)
 	return size;
 }
 
-static size_t copy_to_user_mvcos(void __user *ptr, const void *x, size_t size)
+size_t __copy_from_user(void *to, const void __user *from, size_t n)
+{
+	if (static_key_true(&have_mvcos))
+		return copy_from_user_mvcos(to, from, n);
+	return copy_from_user_pt(to, from, n);
+}
+EXPORT_SYMBOL(__copy_from_user);
+
+static inline size_t copy_to_user_mvcos(void __user *ptr, const void *x,
+					size_t size)
 {
 	register unsigned long reg0 asm("0") = 0x810000UL;
 	unsigned long tmp1, tmp2;
@@ -94,8 +108,16 @@ static size_t copy_to_user_mvcos(void __user *ptr, const void *x, size_t size)
 	return size;
 }
 
-static size_t copy_in_user_mvcos(void __user *to, const void __user *from,
-				 size_t size)
+size_t __copy_to_user(void __user *to, const void *from, size_t n)
+{
+	if (static_key_true(&have_mvcos))
+		return copy_to_user_mvcos(to, from, n);
+	return copy_to_user_pt(to, from, n);
+}
+EXPORT_SYMBOL(__copy_to_user);
+
+static inline size_t copy_in_user_mvcos(void __user *to, const void __user *from,
+					size_t size)
 {
 	register unsigned long reg0 asm("0") = 0x810081UL;
 	unsigned long tmp1, tmp2;
@@ -117,7 +139,15 @@ static size_t copy_in_user_mvcos(void __user *to, const void __user *from,
 	return size;
 }
 
-static size_t clear_user_mvcos(void __user *to, size_t size)
+size_t __copy_in_user(void __user *to, const void __user *from, size_t n)
+{
+	if (static_key_true(&have_mvcos))
+		return copy_in_user_mvcos(to, from, n);
+	return copy_in_user_pt(to, from, n);
+}
+EXPORT_SYMBOL(__copy_in_user);
+
+static inline size_t clear_user_mvcos(void __user *to, size_t size)
 {
 	register unsigned long reg0 asm("0") = 0x810000UL;
 	unsigned long tmp1, tmp2;
@@ -145,7 +175,15 @@ static size_t clear_user_mvcos(void __user *to, size_t size)
 	return size;
 }
 
-static size_t strnlen_user_mvcos(const char __user *src, size_t count)
+size_t __clear_user(void __user *to, size_t size)
+{
+	if (static_key_true(&have_mvcos))
+		return clear_user_mvcos(to, size);
+	return clear_user_pt(to, size);
+}
+EXPORT_SYMBOL(__clear_user);
+
+static inline size_t strnlen_user_mvcos(const char __user *src, size_t count)
 {
 	size_t done, len, offset, len_str;
 	char buf[256];
@@ -164,10 +202,18 @@ static size_t strnlen_user_mvcos(const char __user *src, size_t count)
 	return done + 1;
 }
 
-static size_t strncpy_from_user_mvcos(char *dst, const char __user *src,
-				      size_t count)
+size_t __strnlen_user(const char __user *src, size_t count)
 {
-	size_t done, len, offset, len_str;
+	if (static_key_true(&have_mvcos))
+		return strnlen_user_mvcos(src, count);
+	return strnlen_user_pt(src, count);
+}
+EXPORT_SYMBOL(__strnlen_user);
+
+static inline size_t strncpy_from_user_mvcos(char *dst, const char __user *src,
+					     size_t count)
+{
+	unsigned long done, len, offset, len_str;
 
 	if (unlikely(!count))
 		return 0;
@@ -185,13 +231,18 @@ static size_t strncpy_from_user_mvcos(char *dst, const char __user *src,
 	return done;
 }
 
-struct uaccess_ops uaccess_mvcos = {
-	.copy_from_user = copy_from_user_mvcos,
-	.copy_to_user = copy_to_user_mvcos,
-	.copy_in_user = copy_in_user_mvcos,
-	.clear_user = clear_user_mvcos,
-	.strnlen_user = strnlen_user_mvcos,
-	.strncpy_from_user = strncpy_from_user_mvcos,
-	.futex_atomic_op = futex_atomic_op_pt,
-	.futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
-};
+long __strncpy_from_user(char *dst, const char __user *src, long count)
+{
+	if (static_key_true(&have_mvcos))
+		return strncpy_from_user_mvcos(dst, src, count);
+	return strncpy_from_user_pt(dst, src, count);
+}
+EXPORT_SYMBOL(__strncpy_from_user);
+
+static int __init uaccess_init(void)
+{
+	if (!MACHINE_HAS_MVCOS)
+		static_key_slow_dec(&have_mvcos);
+	return 0;
+}
+early_initcall(uaccess_init);