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e430824f | 1 | /* Linux-specific atomic operations for Nios II Linux. |
7adcbafe | 2 | Copyright (C) 2008-2022 Free Software Foundation, Inc. |
e430824f CLT |
3 | |
4 | This file is free software; you can redistribute it and/or modify it | |
5 | under the terms of the GNU General Public License as published by the | |
6 | Free Software Foundation; either version 3, or (at your option) any | |
7 | later version. | |
8 | ||
9 | This file is distributed in the hope that it will be useful, but | |
10 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | General Public License for more details. | |
13 | ||
14 | Under Section 7 of GPL version 3, you are granted additional | |
15 | permissions described in the GCC Runtime Library Exception, version | |
16 | 3.1, as published by the Free Software Foundation. | |
17 | ||
18 | You should have received a copy of the GNU General Public License and | |
19 | a copy of the GCC Runtime Library Exception along with this program; | |
20 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
21 | <http://www.gnu.org/licenses/>. */ | |
22 | ||
e430824f CLT |
23 | /* We implement byte, short and int versions of each atomic operation |
24 | using the kernel helper defined below. There is no support for | |
25 | 64-bit operations yet. */ | |
26 | ||
27 | /* Crash a userspace program with SIGSEV. */ | |
28 | #define ABORT_INSTRUCTION asm ("stw zero, 0(zero)") | |
29 | ||
30 | /* Kernel helper for compare-and-exchange a 32-bit value. */ | |
31 | static inline long | |
32 | __kernel_cmpxchg (int oldval, int newval, int *mem) | |
33 | { | |
34 | register int r2 asm ("r2"); | |
35 | register int *r4 asm ("r4") = mem; | |
36 | register int r5 asm ("r5") = oldval; | |
37 | register int r6 asm ("r6") = newval; | |
38 | ||
39 | /* Call the kernel provided fixed address cmpxchg helper routine. */ | |
40 | asm volatile ("movi %0, %4\n\t" | |
41 | "callr %0\n" | |
42 | : "=r" (r2) | |
43 | : "r" (r4), "r" (r5), "r" (r6), "I" (0x00001004) | |
44 | : "ra", "memory"); | |
45 | return r2; | |
46 | } | |
47 | ||
48 | #define HIDDEN __attribute__ ((visibility ("hidden"))) | |
49 | ||
50 | #ifdef __nios2_little_endian__ | |
51 | #define INVERT_MASK_1 0 | |
52 | #define INVERT_MASK_2 0 | |
53 | #else | |
54 | #define INVERT_MASK_1 24 | |
55 | #define INVERT_MASK_2 16 | |
56 | #endif | |
57 | ||
58 | #define MASK_1 0xffu | |
59 | #define MASK_2 0xffffu | |
60 | ||
61 | #define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP) \ | |
62 | int HIDDEN \ | |
63 | __sync_fetch_and_##OP##_4 (int *ptr, int val) \ | |
64 | { \ | |
65 | int failure, tmp; \ | |
66 | \ | |
67 | do { \ | |
68 | tmp = *ptr; \ | |
69 | failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr); \ | |
70 | } while (failure != 0); \ | |
71 | \ | |
72 | return tmp; \ | |
73 | } | |
74 | ||
75 | FETCH_AND_OP_WORD (add, , +) | |
76 | FETCH_AND_OP_WORD (sub, , -) | |
77 | FETCH_AND_OP_WORD (or, , |) | |
78 | FETCH_AND_OP_WORD (and, , &) | |
79 | FETCH_AND_OP_WORD (xor, , ^) | |
80 | FETCH_AND_OP_WORD (nand, ~, &) | |
81 | ||
82 | #define NAME_oldval(OP, WIDTH) __sync_fetch_and_##OP##_##WIDTH | |
83 | #define NAME_newval(OP, WIDTH) __sync_##OP##_and_fetch_##WIDTH | |
84 | ||
85 | /* Implement both __sync_<op>_and_fetch and __sync_fetch_and_<op> for | |
86 | subword-sized quantities. */ | |
87 | ||
88 | #define SUBWORD_SYNC_OP(OP, PFX_OP, INF_OP, TYPE, WIDTH, RETURN) \ | |
89 | TYPE HIDDEN \ | |
90 | NAME##_##RETURN (OP, WIDTH) (TYPE *ptr, TYPE val) \ | |
91 | { \ | |
92 | int *wordptr = (int *) ((unsigned long) ptr & ~3); \ | |
93 | unsigned int mask, shift, oldval, newval; \ | |
94 | int failure; \ | |
95 | \ | |
96 | shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \ | |
97 | mask = MASK_##WIDTH << shift; \ | |
98 | \ | |
99 | do { \ | |
100 | oldval = *wordptr; \ | |
101 | newval = ((PFX_OP (((oldval & mask) >> shift) \ | |
102 | INF_OP (unsigned int) val)) << shift) & mask; \ | |
103 | newval |= oldval & ~mask; \ | |
104 | failure = __kernel_cmpxchg (oldval, newval, wordptr); \ | |
105 | } while (failure != 0); \ | |
106 | \ | |
107 | return (RETURN & mask) >> shift; \ | |
108 | } | |
109 | ||
110 | SUBWORD_SYNC_OP (add, , +, unsigned short, 2, oldval) | |
111 | SUBWORD_SYNC_OP (sub, , -, unsigned short, 2, oldval) | |
112 | SUBWORD_SYNC_OP (or, , |, unsigned short, 2, oldval) | |
113 | SUBWORD_SYNC_OP (and, , &, unsigned short, 2, oldval) | |
114 | SUBWORD_SYNC_OP (xor, , ^, unsigned short, 2, oldval) | |
115 | SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, oldval) | |
116 | ||
117 | SUBWORD_SYNC_OP (add, , +, unsigned char, 1, oldval) | |
118 | SUBWORD_SYNC_OP (sub, , -, unsigned char, 1, oldval) | |
119 | SUBWORD_SYNC_OP (or, , |, unsigned char, 1, oldval) | |
120 | SUBWORD_SYNC_OP (and, , &, unsigned char, 1, oldval) | |
121 | SUBWORD_SYNC_OP (xor, , ^, unsigned char, 1, oldval) | |
122 | SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, oldval) | |
123 | ||
124 | #define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP) \ | |
125 | int HIDDEN \ | |
126 | __sync_##OP##_and_fetch_4 (int *ptr, int val) \ | |
127 | { \ | |
128 | int tmp, failure; \ | |
129 | \ | |
130 | do { \ | |
131 | tmp = *ptr; \ | |
132 | failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr); \ | |
133 | } while (failure != 0); \ | |
134 | \ | |
135 | return PFX_OP (tmp INF_OP val); \ | |
136 | } | |
137 | ||
138 | OP_AND_FETCH_WORD (add, , +) | |
139 | OP_AND_FETCH_WORD (sub, , -) | |
140 | OP_AND_FETCH_WORD (or, , |) | |
141 | OP_AND_FETCH_WORD (and, , &) | |
142 | OP_AND_FETCH_WORD (xor, , ^) | |
143 | OP_AND_FETCH_WORD (nand, ~, &) | |
144 | ||
145 | SUBWORD_SYNC_OP (add, , +, unsigned short, 2, newval) | |
146 | SUBWORD_SYNC_OP (sub, , -, unsigned short, 2, newval) | |
147 | SUBWORD_SYNC_OP (or, , |, unsigned short, 2, newval) | |
148 | SUBWORD_SYNC_OP (and, , &, unsigned short, 2, newval) | |
149 | SUBWORD_SYNC_OP (xor, , ^, unsigned short, 2, newval) | |
150 | SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, newval) | |
151 | ||
152 | SUBWORD_SYNC_OP (add, , +, unsigned char, 1, newval) | |
153 | SUBWORD_SYNC_OP (sub, , -, unsigned char, 1, newval) | |
154 | SUBWORD_SYNC_OP (or, , |, unsigned char, 1, newval) | |
155 | SUBWORD_SYNC_OP (and, , &, unsigned char, 1, newval) | |
156 | SUBWORD_SYNC_OP (xor, , ^, unsigned char, 1, newval) | |
157 | SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, newval) | |
158 | ||
159 | int HIDDEN | |
160 | __sync_val_compare_and_swap_4 (int *ptr, int oldval, int newval) | |
161 | { | |
162 | int actual_oldval, fail; | |
163 | ||
164 | while (1) | |
165 | { | |
166 | actual_oldval = *ptr; | |
167 | ||
168 | if (oldval != actual_oldval) | |
169 | return actual_oldval; | |
170 | ||
171 | fail = __kernel_cmpxchg (actual_oldval, newval, ptr); | |
172 | ||
173 | if (!fail) | |
174 | return oldval; | |
175 | } | |
176 | } | |
177 | ||
178 | #define SUBWORD_VAL_CAS(TYPE, WIDTH) \ | |
179 | TYPE HIDDEN \ | |
180 | __sync_val_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \ | |
181 | TYPE newval) \ | |
182 | { \ | |
183 | int *wordptr = (int *)((unsigned long) ptr & ~3), fail; \ | |
184 | unsigned int mask, shift, actual_oldval, actual_newval; \ | |
185 | \ | |
186 | shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \ | |
187 | mask = MASK_##WIDTH << shift; \ | |
188 | \ | |
189 | while (1) \ | |
190 | { \ | |
191 | actual_oldval = *wordptr; \ | |
192 | \ | |
193 | if (((actual_oldval & mask) >> shift) != (unsigned int) oldval) \ | |
194 | return (actual_oldval & mask) >> shift; \ | |
195 | \ | |
196 | actual_newval = (actual_oldval & ~mask) \ | |
197 | | (((unsigned int) newval << shift) & mask); \ | |
198 | \ | |
199 | fail = __kernel_cmpxchg (actual_oldval, actual_newval, \ | |
200 | wordptr); \ | |
201 | \ | |
202 | if (!fail) \ | |
203 | return oldval; \ | |
204 | } \ | |
205 | } | |
206 | ||
207 | SUBWORD_VAL_CAS (unsigned short, 2) | |
208 | SUBWORD_VAL_CAS (unsigned char, 1) | |
209 | ||
210 | typedef unsigned char bool; | |
211 | ||
212 | bool HIDDEN | |
213 | __sync_bool_compare_and_swap_4 (int *ptr, int oldval, int newval) | |
214 | { | |
215 | int failure = __kernel_cmpxchg (oldval, newval, ptr); | |
216 | return (failure == 0); | |
217 | } | |
218 | ||
219 | #define SUBWORD_BOOL_CAS(TYPE, WIDTH) \ | |
220 | bool HIDDEN \ | |
221 | __sync_bool_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \ | |
222 | TYPE newval) \ | |
223 | { \ | |
224 | TYPE actual_oldval \ | |
225 | = __sync_val_compare_and_swap_##WIDTH (ptr, oldval, newval); \ | |
226 | return (oldval == actual_oldval); \ | |
227 | } | |
228 | ||
229 | SUBWORD_BOOL_CAS (unsigned short, 2) | |
230 | SUBWORD_BOOL_CAS (unsigned char, 1) | |
231 | ||
232 | int HIDDEN | |
233 | __sync_lock_test_and_set_4 (int *ptr, int val) | |
234 | { | |
235 | int failure, oldval; | |
236 | ||
237 | do { | |
238 | oldval = *ptr; | |
239 | failure = __kernel_cmpxchg (oldval, val, ptr); | |
240 | } while (failure != 0); | |
241 | ||
242 | return oldval; | |
243 | } | |
244 | ||
245 | #define SUBWORD_TEST_AND_SET(TYPE, WIDTH) \ | |
246 | TYPE HIDDEN \ | |
247 | __sync_lock_test_and_set_##WIDTH (TYPE *ptr, TYPE val) \ | |
248 | { \ | |
249 | int failure; \ | |
250 | unsigned int oldval, newval, shift, mask; \ | |
251 | int *wordptr = (int *) ((unsigned long) ptr & ~3); \ | |
252 | \ | |
253 | shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \ | |
254 | mask = MASK_##WIDTH << shift; \ | |
255 | \ | |
256 | do { \ | |
257 | oldval = *wordptr; \ | |
258 | newval = (oldval & ~mask) \ | |
259 | | (((unsigned int) val << shift) & mask); \ | |
260 | failure = __kernel_cmpxchg (oldval, newval, wordptr); \ | |
261 | } while (failure != 0); \ | |
262 | \ | |
263 | return (oldval & mask) >> shift; \ | |
264 | } | |
265 | ||
266 | SUBWORD_TEST_AND_SET (unsigned short, 2) | |
267 | SUBWORD_TEST_AND_SET (unsigned char, 1) | |
268 | ||
269 | #define SYNC_LOCK_RELEASE(TYPE, WIDTH) \ | |
270 | void HIDDEN \ | |
271 | __sync_lock_release_##WIDTH (TYPE *ptr) \ | |
272 | { \ | |
273 | /* All writes before this point must be seen before we release \ | |
274 | the lock itself. */ \ | |
275 | __builtin_sync (); \ | |
276 | *ptr = 0; \ | |
277 | } | |
278 | ||
279 | SYNC_LOCK_RELEASE (int, 4) | |
280 | SYNC_LOCK_RELEASE (short, 2) | |
281 | SYNC_LOCK_RELEASE (char, 1) |