-/*
- * Atomic compare and exchange. Compare OLD with MEM, if identical,
- * store NEW in MEM. Return the initial value in MEM. Success is
- * indicated by comparing RETURN with OLD.
- */
-
-#define __HAVE_ARCH_CMPXCHG
-
-extern void __cmpxchg_called_with_bad_pointer(void);
-
-static inline unsigned long __cmpxchg(void *ptr, unsigned long old,
- unsigned long new, int size)
-{
- unsigned long addr, prev, tmp;
- int shift;
-
- switch (size) {
- case 1:
- addr = (unsigned long) ptr;
- shift = (3 ^ (addr & 3)) << 3;
- addr ^= addr & 3;
- asm volatile(
- " l %0,%2\n"
- "0: nr %0,%5\n"
- " lr %1,%0\n"
- " or %0,%3\n"
- " or %1,%4\n"
- " cs %0,%1,%2\n"
- " jnl 1f\n"
- " xr %1,%0\n"
- " nr %1,%5\n"
- " jnz 0b\n"
- "1:"
- : "=&d" (prev), "=&d" (tmp), "+Q" (*(int *) addr)
- : "d" ((old & 0xff) << shift),
- "d" ((new & 0xff) << shift),
- "d" (~(0xff << shift))
- : "memory", "cc");
- return prev >> shift;
- case 2:
- addr = (unsigned long) ptr;
- shift = (2 ^ (addr & 2)) << 3;
- addr ^= addr & 2;
- asm volatile(
- " l %0,%2\n"
- "0: nr %0,%5\n"
- " lr %1,%0\n"
- " or %0,%3\n"
- " or %1,%4\n"
- " cs %0,%1,%2\n"
- " jnl 1f\n"
- " xr %1,%0\n"
- " nr %1,%5\n"
- " jnz 0b\n"
- "1:"
- : "=&d" (prev), "=&d" (tmp), "+Q" (*(int *) addr)
- : "d" ((old & 0xffff) << shift),
- "d" ((new & 0xffff) << shift),
- "d" (~(0xffff << shift))
- : "memory", "cc");
- return prev >> shift;
- case 4:
- asm volatile(
- " cs %0,%3,%1\n"
- : "=&d" (prev), "=Q" (*(int *) ptr)
- : "0" (old), "d" (new), "Q" (*(int *) ptr)
- : "memory", "cc");
- return prev;
-#ifdef CONFIG_64BIT
- case 8:
- asm volatile(
- " csg %0,%3,%1\n"
- : "=&d" (prev), "=Q" (*(long *) ptr)
- : "0" (old), "d" (new), "Q" (*(long *) ptr)
- : "memory", "cc");
- return prev;
-#endif /* CONFIG_64BIT */
- }
- __cmpxchg_called_with_bad_pointer();
- return old;
-}
-
-#define cmpxchg(ptr, o, n) \
-({ \
- __typeof__(*(ptr)) __ret; \
- __ret = (__typeof__(*(ptr))) \
- __cmpxchg((ptr), (unsigned long)(o), (unsigned long)(n), \
- sizeof(*(ptr))); \
- __ret; \
-})