1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ALPHA_CMPXCHG_H
3 #error Do not include xchg.h directly!
6 * xchg/xchg_local and cmpxchg/cmpxchg_local share the same code
7 * except that local version do not have the expensive memory barrier.
8 * So this file is included twice from asm/cmpxchg.h.
13 * Since it can be used to implement critical sections
14 * it must clobber "memory" (also for interrupts in UP).
17 static inline unsigned long
18 ____xchg(_u8, volatile char *m, unsigned long val)
20 unsigned long ret, tmp, addr64;
35 : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
36 : "r" ((long)m), "1" (val) : "memory");
41 static inline unsigned long
42 ____xchg(_u16, volatile short *m, unsigned long val)
44 unsigned long ret, tmp, addr64;
59 : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
60 : "r" ((long)m), "1" (val) : "memory");
65 static inline unsigned long
66 ____xchg(_u32, volatile int *m, unsigned long val)
79 : "=&r" (val), "=&r" (dummy), "=m" (*m)
80 : "rI" (val), "m" (*m) : "memory");
85 static inline unsigned long
86 ____xchg(_u64, volatile long *m, unsigned long val)
99 : "=&r" (val), "=&r" (dummy), "=m" (*m)
100 : "rI" (val), "m" (*m) : "memory");
105 /* This function doesn't exist, so you'll get a linker error
106 if something tries to do an invalid xchg(). */
107 extern void __xchg_called_with_bad_pointer(void);
109 static __always_inline unsigned long
110 ____xchg(, volatile void *ptr, unsigned long x, int size)
114 return ____xchg(_u8, ptr, x);
116 return ____xchg(_u16, ptr, x);
118 return ____xchg(_u32, ptr, x);
120 return ____xchg(_u64, ptr, x);
122 __xchg_called_with_bad_pointer();
127 * Atomic compare and exchange. Compare OLD with MEM, if identical,
128 * store NEW in MEM. Return the initial value in MEM. Success is
129 * indicated by comparing RETURN with OLD.
131 * The memory barrier is placed in SMP unconditionally, in order to
132 * guarantee that dependency ordering is preserved when a dependency
133 * is headed by an unsuccessful operation.
136 static inline unsigned long
137 ____cmpxchg(_u8, volatile char *m, unsigned char old, unsigned char new)
139 unsigned long prev, tmp, cmp, addr64;
141 __asm__ __volatile__(
144 "1: ldq_l %2,0(%4)\n"
157 : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
158 : "r" ((long)m), "Ir" (old), "1" (new) : "memory");
163 static inline unsigned long
164 ____cmpxchg(_u16, volatile short *m, unsigned short old, unsigned short new)
166 unsigned long prev, tmp, cmp, addr64;
168 __asm__ __volatile__(
171 "1: ldq_l %2,0(%4)\n"
184 : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
185 : "r" ((long)m), "Ir" (old), "1" (new) : "memory");
190 static inline unsigned long
191 ____cmpxchg(_u32, volatile int *m, int old, int new)
193 unsigned long prev, cmp;
195 __asm__ __volatile__(
207 : "=&r"(prev), "=&r"(cmp), "=m"(*m)
208 : "r"((long) old), "r"(new), "m"(*m) : "memory");
213 static inline unsigned long
214 ____cmpxchg(_u64, volatile long *m, unsigned long old, unsigned long new)
216 unsigned long prev, cmp;
218 __asm__ __volatile__(
230 : "=&r"(prev), "=&r"(cmp), "=m"(*m)
231 : "r"((long) old), "r"(new), "m"(*m) : "memory");
236 /* This function doesn't exist, so you'll get a linker error
237 if something tries to do an invalid cmpxchg(). */
238 extern void __cmpxchg_called_with_bad_pointer(void);
240 static __always_inline unsigned long
241 ____cmpxchg(, volatile void *ptr, unsigned long old, unsigned long new,
246 return ____cmpxchg(_u8, ptr, old, new);
248 return ____cmpxchg(_u16, ptr, old, new);
250 return ____cmpxchg(_u32, ptr, old, new);
252 return ____cmpxchg(_u64, ptr, old, new);
254 __cmpxchg_called_with_bad_pointer();