Subversion Repositories HelenOS-historic

Rev

Rev 532 | Rev 1434 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
153 jermar 1
/*
2
 * Copyright (C) 2005 Jakub Jermar
3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
13
 *   documentation and/or other materials provided with the distribution.
14
 * - The name of the author may not be used to endorse or promote products
15
 *   derived from this software without specific prior written permission.
16
 *
17
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
29
#ifndef __ia32_BARRIER_H__
30
#define __ia32_BARRIER_H__
31
 
469 jermar 32
#include <arch/types.h>
33
 
153 jermar 34
/*
35
 * NOTE:
36
 * No barriers for critical section (i.e. spinlock) on IA-32 are needed:
37
 * - spinlock_lock() and spinlock_trylock() use serializing XCHG instruction
38
 * - writes cannot pass reads on IA-32 => spinlock_unlock() needs no barriers
39
 */
40
 
41
/*
42
 * Provisions are made to prevent compiler from reordering instructions itself.
43
 */
44
 
45
#define CS_ENTER_BARRIER()  __asm__ volatile ("" ::: "memory")
46
#define CS_LEAVE_BARRIER()  __asm__ volatile ("" ::: "memory")
47
 
469 jermar 48
static inline void cpuid_serialization(void)
49
{
50
    __asm__ volatile (
51
        "xorl %%eax, %%eax\n"
52
        "cpuid\n"
53
        ::: "eax", "ebx", "ecx", "edx", "memory"
54
    );
55
}
56
 
468 decky 57
#ifdef CONFIG_FENCES_P4
470 jermar 58
#   define memory_barrier()     __asm__ volatile ("mfence\n" ::: "memory")
468 decky 59
#   define read_barrier()       __asm__ volatile ("lfence\n" ::: "memory")
470 jermar 60
#   ifdef CONFIG_WEAK_MEMORY
61
#       define write_barrier()  __asm__ volatile ("sfence\n" ::: "memory")
62
#   else
63
#       define write_barrier()
64
#   endif
468 decky 65
#elif CONFIG_FENCES_P3
469 jermar 66
#   define memory_barrier()     cpuid_serialization()
67
#   define read_barrier()       cpuid_serialization()
470 jermar 68
#   ifdef CONFIG_WEAK_MEMORY
69
#       define write_barrier()  __asm__ volatile ("sfence\n" ::: "memory")
70
#   else
71
#       define write_barrier()
72
#   endif
469 jermar 73
#else
74
#   define memory_barrier()     cpuid_serialization()
75
#   define read_barrier()       cpuid_serialization()
470 jermar 76
#   ifdef CONFIG_WEAK_MEMORY
77
#       define write_barrier()  cpuid_serialization()
78
#   else
79
#       define write_barrier()
80
#   endif
153 jermar 81
#endif
423 decky 82
 
83
#endif