From Ivan Kokshaysky <ink@jurassic.park.msu.ru>:

Implement alpha xchg and cmpxchg for 8 and 16 bit quantities.

include/asm-alpha/system.h

@@ -366,7 +366,59 @@ extern void __global_restore_flags(unsigned long flags);
  * it must clobber "memory" (also for interrupts in UP).
  */
 
-extern __inline__ unsigned long
+static inline unsigned long
+__xchg_u8(volatile char *m, unsigned long val)
+{
+	unsigned long ret, tmp, addr64;
+
+	__asm__ __volatile__(
+	"	andnot	%4,7,%3\n"
+	"	insbl	%1,%4,%1\n"
+	"1:	ldq_l	%2,0(%3)\n"
+	"	extbl	%2,%4,%0\n"
+	"	mskbl	%2,%4,%2\n"
+	"	or	%1,%2,%2\n"
+	"	stq_c	%2,0(%3)\n"
+	"	beq	%2,2f\n"
+#ifdef CONFIG_SMP
+	"	mb\n"
+#endif
+	".subsection 2\n"
+	"2:	br	1b\n"
+	".previous"
+	: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
+	: "r" ((long)m), "1" (val) : "memory");
+
+	return ret;
+}
+
+static inline unsigned long
+__xchg_u16(volatile short *m, unsigned long val)
+{
+	unsigned long ret, tmp, addr64;
+
+	__asm__ __volatile__(
+	"	andnot	%4,7,%3\n"
+	"	inswl	%1,%4,%1\n"
+	"1:	ldq_l	%2,0(%3)\n"
+	"	extwl	%2,%4,%0\n"
+	"	mskwl	%2,%4,%2\n"
+	"	or	%1,%2,%2\n"
+	"	stq_c	%2,0(%3)\n"
+	"	beq	%2,2f\n"
+#ifdef CONFIG_SMP
+	"	mb\n"
+#endif
+	".subsection 2\n"
+	"2:	br	1b\n"
+	".previous"
+	: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
+	: "r" ((long)m), "1" (val) : "memory");
+
+	return ret;
+}
+
+static inline unsigned long
 __xchg_u32(volatile int *m, unsigned long val)
 {
 	unsigned long dummy;
@@ -388,7 +440,7 @@ __xchg_u32(volatile int *m, unsigned long val)
 	return val;
 }
 
-extern __inline__ unsigned long
+static inline unsigned long
 __xchg_u64(volatile long *m, unsigned long val)
 {
 	unsigned long dummy;
@@ -414,10 +466,14 @@ __xchg_u64(volatile long *m, unsigned long val)
    if something tries to do an invalid xchg().  */
 extern void __xchg_called_with_bad_pointer(void);
 
-static __inline__ unsigned long
+static inline unsigned long
 __xchg(volatile void *ptr, unsigned long x, int size)
 {
 	switch (size) {
+		case 1:
+			return __xchg_u8(ptr, x);
+		case 2:
+			return __xchg_u16(ptr, x);
 		case 4:
 			return __xchg_u32(ptr, x);
 		case 8:
@@ -449,7 +505,65 @@ __xchg(volatile void *ptr, unsigned long x, int size)
 
 #define __HAVE_ARCH_CMPXCHG 1
 
-extern __inline__ unsigned long
+static inline unsigned long
+__cmpxchg_u8(volatile char *m, long old, long new)
+{
+	unsigned long prev, tmp, cmp, addr64;
+
+	__asm__ __volatile__(
+	"	andnot	%5,7,%4\n"
+	"	insbl	%1,%5,%1\n"
+	"1:	ldq_l	%2,0(%4)\n"
+	"	extbl	%2,%5,%0\n"
+	"	cmpeq	%0,%6,%3\n"
+	"	beq	%3,2f\n"
+	"	mskbl	%2,%5,%2\n"
+	"	or	%1,%2,%2\n"
+	"	stq_c	%2,0(%4)\n"
+	"	beq	%2,3f\n"
+#ifdef CONFIG_SMP
+	"	mb\n"
+#endif
+	"2:\n"
+	".subsection 2\n"
+	"3:	br	1b\n"
+	".previous"
+	: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
+	: "r" ((long)m), "Ir" (old), "1" (new) : "memory");
+
+	return prev;
+}
+
+static inline unsigned long
+__cmpxchg_u16(volatile short *m, long old, long new)
+{
+	unsigned long prev, tmp, cmp, addr64;
+
+	__asm__ __volatile__(
+	"	andnot	%5,7,%4\n"
+	"	inswl	%1,%5,%1\n"
+	"1:	ldq_l	%2,0(%4)\n"
+	"	extwl	%2,%5,%0\n"
+	"	cmpeq	%0,%6,%3\n"
+	"	beq	%3,2f\n"
+	"	mskwl	%2,%5,%2\n"
+	"	or	%1,%2,%2\n"
+	"	stq_c	%2,0(%4)\n"
+	"	beq	%2,3f\n"
+#ifdef CONFIG_SMP
+	"	mb\n"
+#endif
+	"2:\n"
+	".subsection 2\n"
+	"3:	br	1b\n"
+	".previous"
+	: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
+	: "r" ((long)m), "Ir" (old), "1" (new) : "memory");
+
+	return prev;
+}
+
+static inline unsigned long
 __cmpxchg_u32(volatile int *m, int old, int new)
 {
 	unsigned long prev, cmp;
@@ -474,7 +588,7 @@ __cmpxchg_u32(volatile int *m, int old, int new)
 	return prev;
 }
 
-extern __inline__ unsigned long
+static inline unsigned long
 __cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
 {
 	unsigned long prev, cmp;
@@ -503,10 +617,14 @@ __cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
    if something tries to do an invalid cmpxchg().  */
 extern void __cmpxchg_called_with_bad_pointer(void);
 
-static __inline__ unsigned long
+static inline unsigned long
 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
 {
 	switch (size) {
+		case 1:
+			return __cmpxchg_u8(ptr, old, new);
+		case 2:
+			return __cmpxchg_u16(ptr, old, new);
 		case 4:
 			return __cmpxchg_u32(ptr, old, new);
 		case 8: