urcu/arch/x86.h

   1 #ifndef _URCU_ARCH_X86_H
   2 #define _URCU_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@efficios.com>
   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 <urcu/compiler.h>
  26 #include <urcu/config.h>
  27 #include <urcu/syscall-compat.h>
  28
  29 #ifdef __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 #define CAA_CACHE_LINE_SIZE     128
  34
  35 #ifdef CONFIG_RCU_HAVE_FENCE
  36 #define cmm_mb()    __asm__ __volatile__ ("mfence":::"memory")
  37
  38 /*
  39  * Define cmm_rmb/cmm_wmb to "strict" barriers that may be needed when
  40  * using SSE or working with I/O areas.  cmm_smp_rmb/cmm_smp_wmb are
  41  * only compiler barriers, which is enough for general use.
  42  */
  43 #define cmm_rmb()     __asm__ __volatile__ ("lfence":::"memory")
  44 #define cmm_wmb()     __asm__ __volatile__ ("sfence"::: "memory")
  45 #define cmm_smp_rmb() cmm_barrier()
  46 #define cmm_smp_wmb() cmm_barrier()
  47 #else
  48 /*
  49  * We leave smp_rmb/smp_wmb as full barriers for processors that do not have
  50  * fence instructions.
  51  *
  52  * An empty cmm_smp_rmb() may not be enough on old PentiumPro multiprocessor
  53  * systems, due to an erratum.  The Linux kernel says that "Even distro
  54  * kernels should think twice before enabling this", but for now let's
  55  * be conservative and leave the full barrier on 32-bit processors.  Also,
  56  * IDT WinChip supports weak store ordering, and the kernel may enable it
  57  * under our feet; cmm_smp_wmb() ceases to be a nop for these processors.
  58  */
  59 #if (CAA_BITS_PER_LONG == 32)
  60 #define cmm_mb()    __asm__ __volatile__ ("lock; addl $0,0(%%esp)":::"memory")
  61 #define cmm_rmb()    __asm__ __volatile__ ("lock; addl $0,0(%%esp)":::"memory")
  62 #define cmm_wmb()    __asm__ __volatile__ ("lock; addl $0,0(%%esp)":::"memory")
  63 #else
  64 #define cmm_mb()    __asm__ __volatile__ ("lock; addl $0,0(%%rsp)":::"memory")
  65 #define cmm_rmb()    __asm__ __volatile__ ("lock; addl $0,0(%%rsp)":::"memory")
  66 #define cmm_wmb()    __asm__ __volatile__ ("lock; addl $0,0(%%rsp)":::"memory")
  67 #endif
  68 #endif
  69
  70 #define caa_cpu_relax() __asm__ __volatile__ ("rep; nop" : : : "memory")
  71
  72 #define rdtscll(val)                                                      \
  73         do {                                                              \
  74              unsigned int __a, __d;                                       \
  75              __asm__ __volatile__ ("rdtsc" : "=a" (__a), "=d" (__d));     \
  76              (val) = ((unsigned long long)__a)                            \
  77                         | (((unsigned long long)__d) << 32);              \
  78         } while(0)
  79
  80 typedef unsigned long long cycles_t;
  81
  82 static inline cycles_t caa_get_cycles(void)
  83 {
  84         cycles_t ret = 0;
  85
  86         rdtscll(ret);
  87         return ret;
  88 }
  89
  90 /*
  91  * Define the membarrier system call number if not yet available in the
  92  * system headers.
  93  */
  94 #if (CAA_BITS_PER_LONG == 32)
  95 #ifndef __NR_membarrier
  96 #define __NR_membarrier         375
  97 #endif
  98 #else
  99 #ifndef __NR_membarrier
 100 #define __NR_membarrier         324
 101 #endif
 102 #endif
 103
 104 #ifdef __cplusplus
 105 }
 106 #endif
 107
 108 #include <urcu/arch/generic.h>
 109
 110 #endif /* _URCU_ARCH_X86_H */