1 /*
2 * Copyright (c) 2003 Hewlett-Packard Development Company, L.P.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 * SOFTWARE.
21 *
22 * Derived from the corresponding header file for gcc.
23 */
24
25 #include "../loadstore/atomic_load.h"
26 #include "../loadstore/atomic_store.h"
27
28 /* Some architecture set descriptions include special "ordered" memory */
29 /* operations. As far as we can tell, no existing processors actually */
30 /* require those. Nor does it appear likely that future processors */
31 /* will. */
32 /* FIXME: The PA emulator on Itanium may obey weaker restrictions. */
33 /* There should be a mode in which we don't assume sequential */
34 /* consistency here. */
35 #include "../ordered.h"
36
37 #include <machine/inline.h>
38
39 /* GCC will not guarantee the alignment we need, use four lock words */
40 /* and select the correctly aligned datum. See the glibc 2.3.2 */
41 /* linuxthread port for the original implementation. */
42 struct AO_pa_clearable_loc {
43 int data[4];
44 };
45
46 #undef AO_TS_INITIALIZER
47 #define AO_TS_t struct AO_pa_clearable_loc
48 #define AO_TS_INITIALIZER {1,1,1,1}
49 /* Switch meaning of set and clear, since we only have an atomic clear */
50 /* instruction. */
51 typedef enum {AO_PA_TS_set = 0, AO_PA_TS_clear = 1} AO_PA_TS_val;
52 #define AO_TS_VAL_t AO_PA_TS_val
53 #define AO_TS_CLEAR AO_PA_TS_clear
54 #define AO_TS_SET AO_PA_TS_set
55
56 /* The hppa only has one atomic read and modify memory operation, */
57 /* load and clear, so hppa spinlocks must use zero to signify that */
58 /* someone is holding the lock. The address used for the ldcw */
59 /* semaphore must be 16-byte aligned. */
60 #define AO_ldcw(a, ret) \
61 _LDCWX(0 /* index */, 0 /* s */, a /* base */, ret)
62
63 /* Because malloc only guarantees 8-byte alignment for malloc'd data, */
64 /* and GCC only guarantees 8-byte alignment for stack locals, we can't */
65 /* be assured of 16-byte alignment for atomic lock data even if we */
66 /* specify "__attribute ((aligned(16)))" in the type declaration. So, */
67 /* we use a struct containing an array of four ints for the atomic lock */
68 /* type and dynamically select the 16-byte aligned int from the array */
69 /* for the semaphore. */
70 #define AO_PA_LDCW_ALIGNMENT 16
71 #define AO_ldcw_align(addr) \
72 ((volatile unsigned *)(((unsigned long)(addr) \
73 + (AO_PA_LDCW_ALIGNMENT - 1)) \
74 & ~(AO_PA_LDCW_ALIGNMENT - 1)))
75
76 /* Works on PA 1.1 and PA 2.0 systems */
77 AO_INLINE AO_TS_VAL_t
AO_test_and_set_full(volatile AO_TS_t * addr)78 AO_test_and_set_full(volatile AO_TS_t * addr)
79 {
80 register unsigned int ret;
81 register unsigned long a = (unsigned long)AO_ldcw_align(addr);
82
83 # if defined(CPPCHECK)
84 ret = 0; /* to void 'uninitialized variable' warning */
85 # endif
86 AO_ldcw(a, ret);
87 return (AO_TS_VAL_t)ret;
88 }
89 #define AO_HAVE_test_and_set_full
90
91 AO_INLINE void
AO_pa_clear(volatile AO_TS_t * addr)92 AO_pa_clear(volatile AO_TS_t * addr)
93 {
94 volatile unsigned *a = AO_ldcw_align(addr);
95
96 AO_compiler_barrier();
97 *a = 1;
98 }
99 #define AO_CLEAR(addr) AO_pa_clear(addr)
100 #define AO_HAVE_CLEAR
101
102 #undef AO_PA_LDCW_ALIGNMENT
103 #undef AO_ldcw
104 #undef AO_ldcw_align
105