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)	\
22 static 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)							\
65 static __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)			\
107 static 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)						\
135 static 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)						\
151 static __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)					\
233 static 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)						\
258 static __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