1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Based on arch/arm/include/asm/cmpxchg.h
4 *
5 * Copyright (C) 2012 ARM Ltd.
6 */
7#ifndef __ASM_CMPXCHG_H
8#define __ASM_CMPXCHG_H
9
10#include <linux/build_bug.h>
11#include <linux/compiler.h>
12
13#include <asm/barrier.h>
14#include <asm/lse.h>
15
16/*
17 * We need separate acquire parameters for ll/sc and lse, since the full
18 * barrier case is generated as release+dmb for the former and
19 * acquire+release for the latter.
20 */
21#define __XCHG_CASE(w, sfx, name, sz, mb, nop_lse, acq, acq_lse, rel, cl)	\
22static inline u##sz __xchg_case_##name##sz(u##sz x, volatile void *ptr)		\
23{										\
24	u##sz ret;								\
25	unsigned long tmp;							\
26										\
27	asm volatile(ARM64_LSE_ATOMIC_INSN(					\
28	/* LL/SC */								\
29	"	prfm	pstl1strm, %2\n"					\
30	"1:	ld" #acq "xr" #sfx "\t%" #w "0, %2\n"				\
31	"	st" #rel "xr" #sfx "\t%w1, %" #w "3, %2\n"			\
32	"	cbnz	%w1, 1b\n"						\
33	"	" #mb,								\
34	/* LSE atomics */							\
35	"	swp" #acq_lse #rel #sfx "\t%" #w "3, %" #w "0, %2\n"		\
36		__nops(3)							\
37	"	" #nop_lse)							\
38	: "=&r" (ret), "=&r" (tmp), "+Q" (*(u##sz *)ptr)			\
39	: "r" (x)								\
40	: cl);									\
41										\
42	return ret;								\
43}
44
45__XCHG_CASE(w, b,     ,  8,        ,    ,  ,  ,  ,         )
46__XCHG_CASE(w, h,     , 16,        ,    ,  ,  ,  ,         )
47__XCHG_CASE(w,  ,     , 32,        ,    ,  ,  ,  ,         )
48__XCHG_CASE( ,  ,     , 64,        ,    ,  ,  ,  ,         )
49__XCHG_CASE(w, b, acq_,  8,        ,    , a, a,  , "memory")
50__XCHG_CASE(w, h, acq_, 16,        ,    , a, a,  , "memory")
51__XCHG_CASE(w,  , acq_, 32,        ,    , a, a,  , "memory")
52__XCHG_CASE( ,  , acq_, 64,        ,    , a, a,  , "memory")
53__XCHG_CASE(w, b, rel_,  8,        ,    ,  ,  , l, "memory")
54__XCHG_CASE(w, h, rel_, 16,        ,    ,  ,  , l, "memory")
55__XCHG_CASE(w,  , rel_, 32,        ,    ,  ,  , l, "memory")
56__XCHG_CASE( ,  , rel_, 64,        ,    ,  ,  , l, "memory")
57__XCHG_CASE(w, b,  mb_,  8, dmb ish, nop,  , a, l, "memory")
58__XCHG_CASE(w, h,  mb_, 16, dmb ish, nop,  , a, l, "memory")
59__XCHG_CASE(w,  ,  mb_, 32, dmb ish, nop,  , a, l, "memory")
60__XCHG_CASE( ,  ,  mb_, 64, dmb ish, nop,  , a, l, "memory")
61
62#undef __XCHG_CASE
63
64#define __XCHG_GEN(sfx)							\
65static __always_inline  unsigned long __xchg##sfx(unsigned long x,	\
66					volatile void *ptr,		\
67					int size)			\
68{									\
69	switch (size) {							\
70	case 1:								\
71		return __xchg_case##sfx##_8(x, ptr);			\
72	case 2:								\
73		return __xchg_case##sfx##_16(x, ptr);			\
74	case 4:								\
75		return __xchg_case##sfx##_32(x, ptr);			\
76	case 8:								\
77		return __xchg_case##sfx##_64(x, ptr);			\
78	default:							\
79		BUILD_BUG();						\
80	}								\
81									\
82	unreachable();							\
83}
84
85__XCHG_GEN()
86__XCHG_GEN(_acq)
87__XCHG_GEN(_rel)
88__XCHG_GEN(_mb)
89
90#undef __XCHG_GEN
91
92#define __xchg_wrapper(sfx, ptr, x)					\
93({									\
94	__typeof__(*(ptr)) __ret;					\
95	__ret = (__typeof__(*(ptr)))					\
96		__xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
97	__ret;								\
98})
99
100/* xchg */
101#define arch_xchg_relaxed(...)	__xchg_wrapper(    , __VA_ARGS__)
102#define arch_xchg_acquire(...)	__xchg_wrapper(_acq, __VA_ARGS__)
103#define arch_xchg_release(...)	__xchg_wrapper(_rel, __VA_ARGS__)
104#define arch_xchg(...)		__xchg_wrapper( _mb, __VA_ARGS__)
105
106#define __CMPXCHG_CASE(name, sz)			\
107static inline u##sz __cmpxchg_case_##name##sz(volatile void *ptr,	\
108					      u##sz old,		\
109					      u##sz new)		\
110{									\
111	return __lse_ll_sc_body(_cmpxchg_case_##name##sz,		\
112				ptr, old, new);				\
113}
114
115__CMPXCHG_CASE(    ,  8)
116__CMPXCHG_CASE(    , 16)
117__CMPXCHG_CASE(    , 32)
118__CMPXCHG_CASE(    , 64)
119__CMPXCHG_CASE(acq_,  8)
120__CMPXCHG_CASE(acq_, 16)
121__CMPXCHG_CASE(acq_, 32)
122__CMPXCHG_CASE(acq_, 64)
123__CMPXCHG_CASE(rel_,  8)
124__CMPXCHG_CASE(rel_, 16)
125__CMPXCHG_CASE(rel_, 32)
126__CMPXCHG_CASE(rel_, 64)
127__CMPXCHG_CASE(mb_,  8)
128__CMPXCHG_CASE(mb_, 16)
129__CMPXCHG_CASE(mb_, 32)
130__CMPXCHG_CASE(mb_, 64)
131
132#undef __CMPXCHG_CASE
133
134#define __CMPXCHG_DBL(name)						\
135static inline long __cmpxchg_double##name(unsigned long old1,		\
136					 unsigned long old2,		\
137					 unsigned long new1,		\
138					 unsigned long new2,		\
139					 volatile void *ptr)		\
140{									\
141	return __lse_ll_sc_body(_cmpxchg_double##name, 			\
142				old1, old2, new1, new2, ptr);		\
143}
144
145__CMPXCHG_DBL(   )
146__CMPXCHG_DBL(_mb)
147
148#undef __CMPXCHG_DBL
149
150#define __CMPXCHG_GEN(sfx)						\
151static __always_inline unsigned long __cmpxchg##sfx(volatile void *ptr,	\
152					   unsigned long old,		\
153					   unsigned long new,		\
154					   int size)			\
155{									\
156	switch (size) {							\
157	case 1:								\
158		return __cmpxchg_case##sfx##_8(ptr, old, new);		\
159	case 2:								\
160		return __cmpxchg_case##sfx##_16(ptr, old, new);		\
161	case 4:								\
162		return __cmpxchg_case##sfx##_32(ptr, old, new);		\
163	case 8:								\
164		return __cmpxchg_case##sfx##_64(ptr, old, new);		\
165	default:							\
166		BUILD_BUG();						\
167	}								\
168									\
169	unreachable();							\
170}
171
172__CMPXCHG_GEN()
173__CMPXCHG_GEN(_acq)
174__CMPXCHG_GEN(_rel)
175__CMPXCHG_GEN(_mb)
176
177#undef __CMPXCHG_GEN
178
179#define __cmpxchg_wrapper(sfx, ptr, o, n)				\
180({									\
181	__typeof__(*(ptr)) __ret;					\
182	__ret = (__typeof__(*(ptr)))					\
183		__cmpxchg##sfx((ptr), (unsigned long)(o),		\
184				(unsigned long)(n), sizeof(*(ptr)));	\
185	__ret;								\
186})
187
188/* cmpxchg */
189#define arch_cmpxchg_relaxed(...)	__cmpxchg_wrapper(    , __VA_ARGS__)
190#define arch_cmpxchg_acquire(...)	__cmpxchg_wrapper(_acq, __VA_ARGS__)
191#define arch_cmpxchg_release(...)	__cmpxchg_wrapper(_rel, __VA_ARGS__)
192#define arch_cmpxchg(...)		__cmpxchg_wrapper( _mb, __VA_ARGS__)
193#define arch_cmpxchg_local		arch_cmpxchg_relaxed
194
195/* cmpxchg64 */
196#define arch_cmpxchg64_relaxed		arch_cmpxchg_relaxed
197#define arch_cmpxchg64_acquire		arch_cmpxchg_acquire
198#define arch_cmpxchg64_release		arch_cmpxchg_release
199#define arch_cmpxchg64			arch_cmpxchg
200#define arch_cmpxchg64_local		arch_cmpxchg_local
201
202/* cmpxchg_double */
203#define system_has_cmpxchg_double()     1
204
205#define __cmpxchg_double_check(ptr1, ptr2)					\
206({										\
207	if (sizeof(*(ptr1)) != 8)						\
208		BUILD_BUG();							\
209	VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1);	\
210})
211
212#define arch_cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2)				\
213({										\
214	int __ret;								\
215	__cmpxchg_double_check(ptr1, ptr2);					\
216	__ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2),	\
217				     (unsigned long)(n1), (unsigned long)(n2),	\
218				     ptr1);					\
219	__ret;									\
220})
221
222#define arch_cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2)			\
223({										\
224	int __ret;								\
225	__cmpxchg_double_check(ptr1, ptr2);					\
226	__ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2),	\
227				  (unsigned long)(n1), (unsigned long)(n2),	\
228				  ptr1);					\
229	__ret;									\
230})
231
232#define __CMPWAIT_CASE(w, sfx, sz)					\
233static inline void __cmpwait_case_##sz(volatile void *ptr,		\
234				       unsigned long val)		\
235{									\
236	unsigned long tmp;						\
237									\
238	asm volatile(							\
239	"	sevl\n"							\
240	"	wfe\n"							\
241	"	ldxr" #sfx "\t%" #w "[tmp], %[v]\n"			\
242	"	eor	%" #w "[tmp], %" #w "[tmp], %" #w "[val]\n"	\
243	"	cbnz	%" #w "[tmp], 1f\n"				\
244	"	wfe\n"							\
245	"1:"								\
246	: [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr)		\
247	: [val] "r" (val));						\
248}
249
250__CMPWAIT_CASE(w, b, 8);
251__CMPWAIT_CASE(w, h, 16);
252__CMPWAIT_CASE(w,  , 32);
253__CMPWAIT_CASE( ,  , 64);
254
255#undef __CMPWAIT_CASE
256
257#define __CMPWAIT_GEN(sfx)						\
258static __always_inline void __cmpwait##sfx(volatile void *ptr,		\
259				  unsigned long val,			\
260				  int size)				\
261{									\
262	switch (size) {							\
263	case 1:								\
264		return __cmpwait_case##sfx##_8(ptr, (u8)val);		\
265	case 2:								\
266		return __cmpwait_case##sfx##_16(ptr, (u16)val);		\
267	case 4:								\
268		return __cmpwait_case##sfx##_32(ptr, val);		\
269	case 8:								\
270		return __cmpwait_case##sfx##_64(ptr, val);		\
271	default:							\
272		BUILD_BUG();						\
273	}								\
274									\
275	unreachable();							\
276}
277
278__CMPWAIT_GEN()
279
280#undef __CMPWAIT_GEN
281
282#define __cmpwait_relaxed(ptr, val) \
283	__cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr)))
284
285#endif	/* __ASM_CMPXCHG_H */
286