Implementation of xchg primitives derived from MIT license
[urcu.git] / arch_ppc.h
1 #ifndef _ARCH_PPC_H
2 #define _ARCH_PPC_H
3
4 /*
5 * arch_ppc.h: trivial definitions for the powerpc architecture.
6 *
7 * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
8 * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
9 *
10 * This library is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * This library is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with this library; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 #include <compiler.h>
26 #include <arch_atomic.h>
27
28 #define CONFIG_HAVE_FENCE 1
29 #define CONFIG_HAVE_MEM_COHERENCY
30
31 #ifndef BITS_PER_LONG
32 #define BITS_PER_LONG (__SIZEOF_LONG__ * 8)
33 #endif
34
35 #define mb() asm volatile("sync":::"memory")
36 #define rmb() asm volatile("sync":::"memory")
37 #define wmb() asm volatile("sync"::: "memory")
38
39 /*
40 * Architectures without cache coherency need something like the following:
41 *
42 * #define mb() mc()
43 * #define rmb() rmc()
44 * #define wmb() wmc()
45 * #define mc() arch_cache_flush()
46 * #define rmc() arch_cache_flush_read()
47 * #define wmc() arch_cache_flush_write()
48 */
49
50 #define mc() barrier()
51 #define rmc() barrier()
52 #define wmc() barrier()
53
54 /* Assume SMP machine, given we don't have this information */
55 #define CONFIG_SMP 1
56
57 #ifdef CONFIG_SMP
58 #define smp_mb() mb()
59 #define smp_rmb() rmb()
60 #define smp_wmb() wmb()
61 #define smp_mc() mc()
62 #define smp_rmc() rmc()
63 #define smp_wmc() wmc()
64 #else
65 #define smp_mb() barrier()
66 #define smp_rmb() barrier()
67 #define smp_wmb() barrier()
68 #define smp_mc() barrier()
69 #define smp_rmc() barrier()
70 #define smp_wmc() barrier()
71 #endif
72
73 /* Nop everywhere except on alpha. */
74 #define smp_read_barrier_depends()
75
76 static inline void cpu_relax(void)
77 {
78 barrier();
79 }
80
81 #define mftbl() \
82 ({ \
83 unsigned long rval; \
84 asm volatile("mftbl %0" : "=r" (rval)); \
85 rval; \
86 })
87
88 #define mftbu() \
89 ({ \
90 unsigned long rval; \
91 asm volatile("mftbu %0" : "=r" (rval)); \
92 rval; \
93 })
94
95 typedef unsigned long long cycles_t;
96
97 static inline cycles_t get_cycles (void)
98 {
99 long h, l;
100
101 for (;;) {
102 h = mftbu();
103 barrier();
104 l = mftbl();
105 barrier();
106 if (mftbu() == h)
107 return (((cycles_t) h) << 32) + l;
108 }
109 }
110
111 #endif /* _ARCH_PPC_H */
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