1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* 32-bit atomic xchg() and cmpxchg() definitions.
3 *
4 * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
5 * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
6 * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
7 *
8 * Additions by Keith M Wesolowski (wesolows@foobazco.org) based
9 * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
10 */
11
12 #ifndef __ARCH_SPARC_CMPXCHG__
13 #define __ARCH_SPARC_CMPXCHG__
14
15 unsigned long __xchg_u32(volatile u32 *m, u32 new);
16 void __xchg_called_with_bad_pointer(void);
17
__xchg(unsigned long x,__volatile__ void * ptr,int size)18 static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, int size)
19 {
20 switch (size) {
21 case 4:
22 return __xchg_u32(ptr, x);
23 }
24 __xchg_called_with_bad_pointer();
25 return x;
26 }
27
28 #define arch_xchg(ptr,x) ({(__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)));})
29
30 /* Emulate cmpxchg() the same way we emulate atomics,
31 * by hashing the object address and indexing into an array
32 * of spinlocks to get a bit of performance...
33 *
34 * See arch/sparc/lib/atomic32.c for implementation.
35 *
36 * Cribbed from <asm-parisc/atomic.h>
37 */
38
39 /* bug catcher for when unsupported size is used - won't link */
40 void __cmpxchg_called_with_bad_pointer(void);
41 /* we only need to support cmpxchg of a u32 on sparc */
42 unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
43
44 /* don't worry...optimizer will get rid of most of this */
45 static inline unsigned long
__cmpxchg(volatile void * ptr,unsigned long old,unsigned long new_,int size)46 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
47 {
48 switch (size) {
49 case 4:
50 return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
51 default:
52 __cmpxchg_called_with_bad_pointer();
53 break;
54 }
55 return old;
56 }
57
58 #define arch_cmpxchg(ptr, o, n) \
59 ({ \
60 __typeof__(*(ptr)) _o_ = (o); \
61 __typeof__(*(ptr)) _n_ = (n); \
62 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
63 (unsigned long)_n_, sizeof(*(ptr))); \
64 })
65
66 u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new);
67 #define arch_cmpxchg64(ptr, old, new) __cmpxchg_u64(ptr, old, new)
68
69 #include <asm-generic/cmpxchg-local.h>
70
71 /*
72 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
73 * them available.
74 */
75 #define arch_cmpxchg_local(ptr, o, n) \
76 ((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o),\
77 (unsigned long)(n), sizeof(*(ptr))))
78 #define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
79
80 #endif /* __ARCH_SPARC_CMPXCHG__ */
81