arch_x86.h

   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
  87 static inline void rep_nop(void)
  88 {
  89         asm volatile("rep; nop" : : : "memory");
  90 }
  91
  92 static 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  */
 106 static inline void sync_core(void)
 107 {
 108         mb();
 109 }
 110 #else
 111 static 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
 125 typedef unsigned long long cycles_t;
 126
 127 static 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 */