2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org)
8 #ifndef __ASM_CMPXCHG_H
9 #define __ASM_CMPXCHG_H
11 #include <linux/irqflags.h>
14 static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
18 smp_mb__before_llsc();
20 if (kernel_uses_llsc && R10000_LLSC_WAR) {
25 "1: ll %0, %3 # xchg_u32 \n"
32 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
33 : "R" (*m), "Jr" (val)
35 } else if (kernel_uses_llsc) {
41 " ll %0, %3 # xchg_u32 \n"
47 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
48 : "R" (*m), "Jr" (val)
50 } while (unlikely(!dummy));
54 raw_local_irq_save(flags);
57 raw_local_irq_restore(flags); /* implies memory barrier */
66 static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
70 smp_mb__before_llsc();
72 if (kernel_uses_llsc && R10000_LLSC_WAR) {
77 "1: lld %0, %3 # xchg_u64 \n"
82 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
83 : "R" (*m), "Jr" (val)
85 } else if (kernel_uses_llsc) {
91 " lld %0, %3 # xchg_u64 \n"
95 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
96 : "R" (*m), "Jr" (val)
98 } while (unlikely(!dummy));
102 raw_local_irq_save(flags);
105 raw_local_irq_restore(flags); /* implies memory barrier */
113 extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
114 #define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
117 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
121 return __xchg_u32(ptr, x);
123 return __xchg_u64(ptr, x);
129 #define xchg(ptr, x) \
131 BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc); \
133 ((__typeof__(*(ptr))) \
134 __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
137 #define __HAVE_ARCH_CMPXCHG 1
139 #define __cmpxchg_asm(ld, st, m, old, new) \
141 __typeof(*(m)) __ret; \
143 if (kernel_uses_llsc && R10000_LLSC_WAR) { \
144 __asm__ __volatile__( \
148 "1: " ld " %0, %2 # __cmpxchg_asm \n" \
149 " bne %0, %z3, 2f \n" \
153 " " st " $1, %1 \n" \
157 : "=&r" (__ret), "=R" (*m) \
158 : "R" (*m), "Jr" (old), "Jr" (new) \
160 } else if (kernel_uses_llsc) { \
161 __asm__ __volatile__( \
165 "1: " ld " %0, %2 # __cmpxchg_asm \n" \
166 " bne %0, %z3, 2f \n" \
170 " " st " $1, %1 \n" \
174 : "=&r" (__ret), "=R" (*m) \
175 : "R" (*m), "Jr" (old), "Jr" (new) \
178 unsigned long __flags; \
180 raw_local_irq_save(__flags); \
184 raw_local_irq_restore(__flags); \
191 * This function doesn't exist, so you'll get a linker error
192 * if something tries to do an invalid cmpxchg().
194 extern void __cmpxchg_called_with_bad_pointer(void);
196 #define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \
198 __typeof__(ptr) __ptr = (ptr); \
199 __typeof__(*(ptr)) __old = (old); \
200 __typeof__(*(ptr)) __new = (new); \
201 __typeof__(*(ptr)) __res = 0; \
205 switch (sizeof(*(__ptr))) { \
207 __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
210 if (sizeof(long) == 8) { \
211 __res = __cmpxchg_asm("lld", "scd", __ptr, \
216 __cmpxchg_called_with_bad_pointer(); \
225 #define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())
226 #define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , )
228 #define cmpxchg64(ptr, o, n) \
230 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
231 cmpxchg((ptr), (o), (n)); \
235 #define cmpxchg64_local(ptr, o, n) \
237 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
238 cmpxchg_local((ptr), (o), (n)); \
241 #include <asm-generic/cmpxchg-local.h>
242 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
245 #endif /* __ASM_CMPXCHG_H */