Rename CONFIG_URCU_AVOID_SIGNALS to URCU_MB, and README updates
[urcu.git] / arch_x86.h
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1#ifndef _ARCH_X86_H
2#define _ARCH_X86_H
3
4/*
5 * arch_x86.h: trivial definitions for the x86 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/* Assume P4 or newer */
29#define CONFIG_HAVE_FENCE 1
30#define CONFIG_HAVE_MEM_COHERENCY
31
32#ifndef BITS_PER_LONG
33#define BITS_PER_LONG (__SIZEOF_LONG__ * 8)
34#endif
35
36#ifdef CONFIG_HAVE_FENCE
37#define mb() asm volatile("mfence":::"memory")
38#define rmb() asm volatile("lfence":::"memory")
39#define wmb() asm volatile("sfence"::: "memory")
40#else
41/*
42 * Some non-Intel clones support out of order store. wmb() ceases to be a
43 * nop for these.
44 */
45#define mb() asm volatile("lock; addl $0,0(%%esp)":::"memory")
46#define rmb() asm volatile("lock; addl $0,0(%%esp)":::"memory")
47#define wmb() asm volatile("lock; addl $0,0(%%esp)"::: "memory")
48#endif
49
50/*
51 * Architectures without cache coherency need something like the following:
52 *
53 * #define mb() mc()
54 * #define rmb() rmc()
55 * #define wmb() wmc()
56 * #define mc() arch_cache_flush()
57 * #define rmc() arch_cache_flush_read()
58 * #define wmc() arch_cache_flush_write()
59 */
60
61#define mc() barrier()
62#define rmc() barrier()
63#define wmc() barrier()
64
65/* Assume SMP machine, given we don't have this information */
66#define CONFIG_SMP 1
67
68#ifdef CONFIG_SMP
69#define smp_mb() mb()
70#define smp_rmb() rmb()
71#define smp_wmb() wmb()
72#define smp_mc() mc()
73#define smp_rmc() rmc()
74#define smp_wmc() wmc()
75#else
76#define smp_mb() barrier()
77#define smp_rmb() barrier()
78#define smp_wmb() barrier()
79#define smp_mc() barrier()
80#define smp_rmc() barrier()
81#define smp_wmc() barrier()
82#endif
83
84/* Nop everywhere except on alpha. */
85#define smp_read_barrier_depends()
86
87static inline void rep_nop(void)
88{
89 asm volatile("rep; nop" : : : "memory");
90}
91
92static inline void cpu_relax(void)
93{
94 rep_nop();
95}
96
97/*
98 * Serialize core instruction execution. Also acts as a compiler barrier.
99 */
100#ifdef __PIC__
101/*
102 * Cannot use cpuid because it clobbers the ebx register and clashes
103 * with -fPIC :
104 * error: PIC register 'ebx' clobbered in 'asm'
105 */
106static inline void sync_core(void)
107{
108 mb();
109}
110#else
111static inline void sync_core(void)
112{
113 asm volatile("cpuid" : : : "memory", "eax", "ebx", "ecx", "edx");
114}
115#endif
116
117#define rdtscll(val) \
118 do { \
119 unsigned int __a, __d; \
120 asm volatile("rdtsc" : "=a" (__a), "=d" (__d)); \
121 (val) = ((unsigned long long)__a) \
122 | (((unsigned long long)__d) << 32); \
123 } while(0)
124
125typedef unsigned long long cycles_t;
126
127static inline cycles_t get_cycles(void)
128{
129 cycles_t ret = 0;
130
131 rdtscll(ret);
132 return ret;
133}
134
135#endif /* _ARCH_X86_H */
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