1 /*
2 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
3 * Copyright 2007, 2008, 2011 Red Hat, Inc.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #ifndef OS_CPU_LINUX_ZERO_VM_ATOMIC_LINUX_ZERO_INLINE_HPP
27 #define OS_CPU_LINUX_ZERO_VM_ATOMIC_LINUX_ZERO_INLINE_HPP
28
29 #include "orderAccess_linux_zero.inline.hpp"
30 #include "runtime/atomic.hpp"
31 #include "runtime/os.hpp"
32 #include "vm_version_zero.hpp"
33
34 // Implementation of class atomic
35
36 #ifdef M68K
37
38 /*
39 * __m68k_cmpxchg
40 *
41 * Atomically store newval in *ptr if *ptr is equal to oldval for user space.
42 * Returns newval on success and oldval if no exchange happened.
43 * This implementation is processor specific and works on
44 * 68020 68030 68040 and 68060.
45 *
46 * It will not work on ColdFire, 68000 and 68010 since they lack the CAS
47 * instruction.
48 * Using a kernelhelper would be better for arch complete implementation.
49 *
50 */
51
52 static inline int __m68k_cmpxchg(int oldval, int newval, volatile int *ptr) {
53 int ret;
54 __asm __volatile ("cas%.l %0,%2,%1"
55 : "=d" (ret), "+m" (*(ptr))
56 : "d" (newval), "0" (oldval));
57 return ret;
58 }
59
60 /* Perform an atomic compare and swap: if the current value of `*PTR'
61 is OLDVAL, then write NEWVAL into `*PTR'. Return the contents of
62 `*PTR' before the operation.*/
63 static inline int m68k_compare_and_swap(volatile int *ptr,
64 int oldval,
65 int newval) {
66 for (;;) {
67 int prev = *ptr;
68 if (prev != oldval)
69 return prev;
70
71 if (__m68k_cmpxchg (prev, newval, ptr) == newval)
72 // Success.
73 return prev;
74
75 // We failed even though prev == oldval. Try again.
76 }
77 }
78
79 /* Atomically add an int to memory. */
80 static inline int m68k_add_and_fetch(volatile int *ptr, int add_value) {
81 for (;;) {
82 // Loop until success.
83
84 int prev = *ptr;
85
86 if (__m68k_cmpxchg (prev, prev + add_value, ptr) == prev + add_value)
87 return prev + add_value;
88 }
89 }
90
91 /* Atomically write VALUE into `*PTR' and returns the previous
92 contents of `*PTR'. */
93 static inline int m68k_lock_test_and_set(volatile int *ptr, int newval) {
94 for (;;) {
95 // Loop until success.
96 int prev = *ptr;
97
98 if (__m68k_cmpxchg (prev, newval, ptr) == prev)
99 return prev;
100 }
101 }
102 #endif // M68K
103
104 #ifdef ARM
105
106 /*
107 * __kernel_cmpxchg
108 *
109 * Atomically store newval in *ptr if *ptr is equal to oldval for user space.
110 * Return zero if *ptr was changed or non-zero if no exchange happened.
111 * The C flag is also set if *ptr was changed to allow for assembly
112 * optimization in the calling code.
113 *
114 */
115
116 typedef int (__kernel_cmpxchg_t)(int oldval, int newval, volatile int *ptr);
117 #define __kernel_cmpxchg (*(__kernel_cmpxchg_t *) 0xffff0fc0)
118
119
120
121 /* Perform an atomic compare and swap: if the current value of `*PTR'
122 is OLDVAL, then write NEWVAL into `*PTR'. Return the contents of
123 `*PTR' before the operation.*/
124 static inline int arm_compare_and_swap(volatile int *ptr,
125 int oldval,
126 int newval) {
127 for (;;) {
128 int prev = *ptr;
129 if (prev != oldval)
130 return prev;
131
132 if (__kernel_cmpxchg (prev, newval, ptr) == 0)
133 // Success.
134 return prev;
135
136 // We failed even though prev == oldval. Try again.
137 }
138 }
139
140 /* Atomically add an int to memory. */
141 static inline int arm_add_and_fetch(volatile int *ptr, int add_value) {
142 for (;;) {
143 // Loop until a __kernel_cmpxchg succeeds.
144
145 int prev = *ptr;
146
147 if (__kernel_cmpxchg (prev, prev + add_value, ptr) == 0)
148 return prev + add_value;
149 }
150 }
151
152 /* Atomically write VALUE into `*PTR' and returns the previous
153 contents of `*PTR'. */
154 static inline int arm_lock_test_and_set(volatile int *ptr, int newval) {
155 for (;;) {
156 // Loop until a __kernel_cmpxchg succeeds.
157 int prev = *ptr;
158
159 if (__kernel_cmpxchg (prev, newval, ptr) == 0)
160 return prev;
161 }
162 }
163 #endif // ARM
164
165 inline void Atomic::store(jint store_value, volatile jint* dest) {
166 *dest = store_value;
167 }
168
169 inline void Atomic::store_ptr(intptr_t store_value, intptr_t* dest) {
170 *dest = store_value;
171 }
172
173 inline jint Atomic::add(jint add_value, volatile jint* dest) {
174 #ifdef ARM
175 return arm_add_and_fetch(dest, add_value);
176 #else
177 #ifdef M68K
178 return m68k_add_and_fetch(dest, add_value);
179 #else
180 return __sync_add_and_fetch(dest, add_value);
181 #endif // M68K
182 #endif // ARM
183 }
184
185 inline intptr_t Atomic::add_ptr(intptr_t add_value, volatile intptr_t* dest) {
186 #ifdef ARM
187 return arm_add_and_fetch(dest, add_value);
188 #else
189 #ifdef M68K
190 return m68k_add_and_fetch(dest, add_value);
191 #else
192 return __sync_add_and_fetch(dest, add_value);
193 #endif // M68K
194 #endif // ARM
195 }
196
197 inline void* Atomic::add_ptr(intptr_t add_value, volatile void* dest) {
198 return (void *) add_ptr(add_value, (volatile intptr_t *) dest);
199 }
200
201 inline void Atomic::inc(volatile jint* dest) {
202 add(1, dest);
203 }
204
205 inline void Atomic::inc_ptr(volatile intptr_t* dest) {
206 add_ptr(1, dest);
207 }
208
209 inline void Atomic::inc_ptr(volatile void* dest) {
210 add_ptr(1, dest);
211 }
212
213 inline void Atomic::dec(volatile jint* dest) {
214 add(-1, dest);
215 }
216
217 inline void Atomic::dec_ptr(volatile intptr_t* dest) {
218 add_ptr(-1, dest);
219 }
220
221 inline void Atomic::dec_ptr(volatile void* dest) {
222 add_ptr(-1, dest);
223 }
224
225 inline jint Atomic::xchg(jint exchange_value, volatile jint* dest) {
226 #ifdef ARM
227 return arm_lock_test_and_set(dest, exchange_value);
228 #else
229 #ifdef M68K
230 return m68k_lock_test_and_set(dest, exchange_value);
231 #else
232 // __sync_lock_test_and_set is a bizarrely named atomic exchange
233 // operation. Note that some platforms only support this with the
234 // limitation that the only valid value to store is the immediate
235 // constant 1. There is a test for this in JNI_CreateJavaVM().
236 return __sync_lock_test_and_set (dest, exchange_value);
237 #endif // M68K
238 #endif // ARM
239 }
240
241 inline intptr_t Atomic::xchg_ptr(intptr_t exchange_value,
242 volatile intptr_t* dest) {
243 #ifdef ARM
244 return arm_lock_test_and_set(dest, exchange_value);
245 #else
246 #ifdef M68K
247 return m68k_lock_test_and_set(dest, exchange_value);
248 #else
249 return __sync_lock_test_and_set (dest, exchange_value);
250 #endif // M68K
251 #endif // ARM
252 }
253
254 inline void* Atomic::xchg_ptr(void* exchange_value, volatile void* dest) {
255 return (void *) xchg_ptr((intptr_t) exchange_value,
256 (volatile intptr_t*) dest);
257 }
258
259 inline jint Atomic::cmpxchg(jint exchange_value,
260 volatile jint* dest,
261 jint compare_value) {
262 #ifdef ARM
263 return arm_compare_and_swap(dest, compare_value, exchange_value);
264 #else
265 #ifdef M68K
266 return m68k_compare_and_swap(dest, compare_value, exchange_value);
267 #else
268 return __sync_val_compare_and_swap(dest, compare_value, exchange_value);
269 #endif // M68K
270 #endif // ARM
271 }
272
273 inline jlong Atomic::cmpxchg(jlong exchange_value,
274 volatile jlong* dest,
275 jlong compare_value) {
276
277 return __sync_val_compare_and_swap(dest, compare_value, exchange_value);
278 }
279
280 inline intptr_t Atomic::cmpxchg_ptr(intptr_t exchange_value,
281 volatile intptr_t* dest,
282 intptr_t compare_value) {
283 #ifdef ARM
284 return arm_compare_and_swap(dest, compare_value, exchange_value);
285 #else
286 #ifdef M68K
287 return m68k_compare_and_swap(dest, compare_value, exchange_value);
288 #else
289 return __sync_val_compare_and_swap(dest, compare_value, exchange_value);
290 #endif // M68K
291 #endif // ARM
292 }
293
294 inline void* Atomic::cmpxchg_ptr(void* exchange_value,
295 volatile void* dest,
296 void* compare_value) {
297
298 return (void *) cmpxchg_ptr((intptr_t) exchange_value,
299 (volatile intptr_t*) dest,
300 (intptr_t) compare_value);
301 }
302
303 inline jlong Atomic::load(volatile jlong* src) {
304 volatile jlong dest;
305 os::atomic_copy64(src, &dest);
306 return dest;
307 }
308
309 inline void Atomic::store(jlong store_value, jlong* dest) {
310 os::atomic_copy64((volatile jlong*)&store_value, (volatile jlong*)dest);
311 }
312
313 inline void Atomic::store(jlong store_value, volatile jlong* dest) {
314 os::atomic_copy64((volatile jlong*)&store_value, dest);
315 }
316
317 #endif // OS_CPU_LINUX_ZERO_VM_ATOMIC_LINUX_ZERO_INLINE_HPP