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
15unsigned long __xchg_u32(volatile u32 *m, u32 new);
16void __xchg_called_with_bad_pointer(void);
17
18static __always_inline unsigned long __arch_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)))__arch_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 */
40void __cmpxchg_called_with_bad_pointer(void);
41/* we only need to support cmpxchg of a u32 on sparc */
42unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
43
44/* don't worry...optimizer will get rid of most of this */
45static inline unsigned long
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
66u64 __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