1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_ATOMIC_H
3#define _ASM_X86_ATOMIC_H
4
5#include <linux/compiler.h>
6#include <linux/types.h>
7#include <asm/alternative.h>
8#include <asm/cmpxchg.h>
9#include <asm/rmwcc.h>
10#include <asm/barrier.h>
11
12/*
13 * Atomic operations that C can't guarantee us. Useful for
14 * resource counting etc..
15 */
16
17#define ATOMIC_INIT(i) { (i) }
18
19/**
20 * arch_atomic_read - read atomic variable
21 * @v: pointer of type atomic_t
22 *
23 * Atomically reads the value of @v.
24 */
25static __always_inline int arch_atomic_read(const atomic_t *v)
26{
27 /*
28 * Note for KASAN: we deliberately don't use READ_ONCE_NOCHECK() here,
29 * it's non-inlined function that increases binary size and stack usage.
30 */
31 return READ_ONCE((v)->counter);
32}
33
34/**
35 * arch_atomic_set - set atomic variable
36 * @v: pointer of type atomic_t
37 * @i: required value
38 *
39 * Atomically sets the value of @v to @i.
40 */
41static __always_inline void arch_atomic_set(atomic_t *v, int i)
42{
43 WRITE_ONCE(v->counter, i);
44}
45
46/**
47 * arch_atomic_add - add integer to atomic variable
48 * @i: integer value to add
49 * @v: pointer of type atomic_t
50 *
51 * Atomically adds @i to @v.
52 */
53static __always_inline void arch_atomic_add(int i, atomic_t *v)
54{
55 asm volatile(LOCK_PREFIX "addl %1,%0"
56 : "+m" (v->counter)
57 : "ir" (i));
58}
59
60/**
61 * arch_atomic_sub - subtract integer from atomic variable
62 * @i: integer value to subtract
63 * @v: pointer of type atomic_t
64 *
65 * Atomically subtracts @i from @v.
66 */
67static __always_inline void arch_atomic_sub(int i, atomic_t *v)
68{
69 asm volatile(LOCK_PREFIX "subl %1,%0"
70 : "+m" (v->counter)
71 : "ir" (i));
72}
73
74/**
75 * arch_atomic_sub_and_test - subtract value from variable and test result
76 * @i: integer value to subtract
77 * @v: pointer of type atomic_t
78 *
79 * Atomically subtracts @i from @v and returns
80 * true if the result is zero, or false for all
81 * other cases.
82 */
83static __always_inline bool arch_atomic_sub_and_test(int i, atomic_t *v)
84{
85 return GEN_BINARY_RMWcc(LOCK_PREFIX "subl", v->counter, e, "er", i);
86}
87#define arch_atomic_sub_and_test arch_atomic_sub_and_test
88
89/**
90 * arch_atomic_inc - increment atomic variable
91 * @v: pointer of type atomic_t
92 *
93 * Atomically increments @v by 1.
94 */
95static __always_inline void arch_atomic_inc(atomic_t *v)
96{
97 asm volatile(LOCK_PREFIX "incl %0"
98 : "+m" (v->counter));
99}
100#define arch_atomic_inc arch_atomic_inc
101
102/**
103 * arch_atomic_dec - decrement atomic variable
104 * @v: pointer of type atomic_t
105 *
106 * Atomically decrements @v by 1.
107 */
108static __always_inline void arch_atomic_dec(atomic_t *v)
109{
110 asm volatile(LOCK_PREFIX "decl %0"
111 : "+m" (v->counter));
112}
113#define arch_atomic_dec arch_atomic_dec
114
115/**
116 * arch_atomic_dec_and_test - decrement and test
117 * @v: pointer of type atomic_t
118 *
119 * Atomically decrements @v by 1 and
120 * returns true if the result is 0, or false for all other
121 * cases.
122 */
123static __always_inline bool arch_atomic_dec_and_test(atomic_t *v)
124{
125 return GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, e);
126}
127#define arch_atomic_dec_and_test arch_atomic_dec_and_test
128
129/**
130 * arch_atomic_inc_and_test - increment and test
131 * @v: pointer of type atomic_t
132 *
133 * Atomically increments @v by 1
134 * and returns true if the result is zero, or false for all
135 * other cases.
136 */
137static __always_inline bool arch_atomic_inc_and_test(atomic_t *v)
138{
139 return GEN_UNARY_RMWcc(LOCK_PREFIX "incl", v->counter, e);
140}
141#define arch_atomic_inc_and_test arch_atomic_inc_and_test
142
143/**
144 * arch_atomic_add_negative - add and test if negative
145 * @i: integer value to add
146 * @v: pointer of type atomic_t
147 *
148 * Atomically adds @i to @v and returns true
149 * if the result is negative, or false when
150 * result is greater than or equal to zero.
151 */
152static __always_inline bool arch_atomic_add_negative(int i, atomic_t *v)
153{
154 return GEN_BINARY_RMWcc(LOCK_PREFIX "addl", v->counter, s, "er", i);
155}
156#define arch_atomic_add_negative arch_atomic_add_negative
157
158/**
159 * arch_atomic_add_return - add integer and return
160 * @i: integer value to add
161 * @v: pointer of type atomic_t
162 *
163 * Atomically adds @i to @v and returns @i + @v
164 */
165static __always_inline int arch_atomic_add_return(int i, atomic_t *v)
166{
167 return i + xadd(&v->counter, i);
168}
169
170/**
171 * arch_atomic_sub_return - subtract integer and return
172 * @v: pointer of type atomic_t
173 * @i: integer value to subtract
174 *
175 * Atomically subtracts @i from @v and returns @v - @i
176 */
177static __always_inline int arch_atomic_sub_return(int i, atomic_t *v)
178{
179 return arch_atomic_add_return(-i, v);
180}
181
182static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v)
183{
184 return xadd(&v->counter, i);
185}
186
187static __always_inline int arch_atomic_fetch_sub(int i, atomic_t *v)
188{
189 return xadd(&v->counter, -i);
190}
191
192static __always_inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
193{
194 return arch_cmpxchg(&v->counter, old, new);
195}
196
197#define arch_atomic_try_cmpxchg arch_atomic_try_cmpxchg
198static __always_inline bool arch_atomic_try_cmpxchg(atomic_t *v, int *old, int new)
199{
200 return try_cmpxchg(&v->counter, old, new);
201}
202
203static inline int arch_atomic_xchg(atomic_t *v, int new)
204{
205 return arch_xchg(&v->counter, new);
206}
207
208static inline void arch_atomic_and(int i, atomic_t *v)
209{
210 asm volatile(LOCK_PREFIX "andl %1,%0"
211 : "+m" (v->counter)
212 : "ir" (i)
213 : "memory");
214}
215
216static inline int arch_atomic_fetch_and(int i, atomic_t *v)
217{
218 int val = arch_atomic_read(v);
219
220 do { } while (!arch_atomic_try_cmpxchg(v, &val, val & i));
221
222 return val;
223}
224
225static inline void arch_atomic_or(int i, atomic_t *v)
226{
227 asm volatile(LOCK_PREFIX "orl %1,%0"
228 : "+m" (v->counter)
229 : "ir" (i)
230 : "memory");
231}
232
233static inline int arch_atomic_fetch_or(int i, atomic_t *v)
234{
235 int val = arch_atomic_read(v);
236
237 do { } while (!arch_atomic_try_cmpxchg(v, &val, val | i));
238
239 return val;
240}
241
242static inline void arch_atomic_xor(int i, atomic_t *v)
243{
244 asm volatile(LOCK_PREFIX "xorl %1,%0"
245 : "+m" (v->counter)
246 : "ir" (i)
247 : "memory");
248}
249
250static inline int arch_atomic_fetch_xor(int i, atomic_t *v)
251{
252 int val = arch_atomic_read(v);
253
254 do { } while (!arch_atomic_try_cmpxchg(v, &val, val ^ i));
255
256 return val;
257}
258
259#ifdef CONFIG_X86_32
260# include <asm/atomic64_32.h>
261#else
262# include <asm/atomic64_64.h>
263#endif
264
265#include <asm-generic/atomic-instrumented.h>
266
267#endif /* _ASM_X86_ATOMIC_H */
268