[S390] Force link error if xchg/cmpxchg gets called with unsupported size.

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

diff --git a/include/asm-s390/system.h b/include/asm-s390/system.h
index 64a3cd0..d866d33 100644 (file)
--- a/include/asm-s390/system.h
+++ b/include/asm-s390/system.h
@@ -130,6 +130,8 @@ extern void pfault_fini(void);
        __ret;                                                            \
 })
 
+extern void __xchg_called_with_bad_pointer(void);
+
 static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
 {
        unsigned long addr, old;
@@ -150,8 +152,7 @@ static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
                        : "=&d" (old), "=m" (*(int *) addr)
                        : "d" (x << shift), "d" (~(255 << shift)), "a" (addr),
                          "m" (*(int *) addr) : "memory", "cc", "0");
-               x = old >> shift;
-               break;
+               return old >> shift;
        case 2:
                addr = (unsigned long) ptr;
                shift = (2 ^ (addr & 2)) << 3;
@@ -166,8 +167,7 @@ static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
                        : "=&d" (old), "=m" (*(int *) addr)
                        : "d" (x << shift), "d" (~(65535 << shift)), "a" (addr),
                          "m" (*(int *) addr) : "memory", "cc", "0");
-               x = old >> shift;
-               break;
+               return old >> shift;
        case 4:
                asm volatile(
                        "       l       %0,0(%3)\n"
@@ -176,8 +176,7 @@ static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
                        : "=&d" (old), "=m" (*(int *) ptr)
                        : "d" (x), "a" (ptr), "m" (*(int *) ptr)
                        : "memory", "cc");
-               x = old;
-               break;
+               return old;
 #ifdef __s390x__
        case 8:
                asm volatile(
@@ -187,11 +186,11 @@ static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
                        : "=&d" (old), "=m" (*(long *) ptr)
                        : "d" (x), "a" (ptr), "m" (*(long *) ptr)
                        : "memory", "cc");
-               x = old;
-               break;
+               return old;
 #endif /* __s390x__ */
-        }
-        return x;
+       }
+       __xchg_called_with_bad_pointer();
+       return x;
 }
 
 /*
@@ -206,6 +205,8 @@ static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
        ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
                                        (unsigned long)(n),sizeof(*(ptr))))
 
+extern void __cmpxchg_called_with_bad_pointer(void);
+
 static inline unsigned long
 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
 {
@@ -270,7 +271,8 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
                return prev;
 #endif /* __s390x__ */
         }
-        return old;
+       __cmpxchg_called_with_bad_pointer();
+       return old;
 }
 
 /*