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 #include <stdint.h>
  29
  30 #ifdef __cplusplus
  31 extern "C" {
  32 #endif
  33
  34 #define CAA_CACHE_LINE_SIZE     128
  35
  36 #ifdef CONFIG_RCU_HAVE_FENCE
  37 #define cmm_mb()    __asm__ __volatile__ ("mfence":::"memory")
  38
  39 /*
  40  * Define cmm_rmb/cmm_wmb to "strict" barriers that may be needed when
  41  * using SSE or working with I/O areas.  cmm_smp_rmb/cmm_smp_wmb are
  42  * only compiler barriers, which is enough for general use.
  43  */
  44 #define cmm_rmb()     __asm__ __volatile__ ("lfence":::"memory")
  45 #define cmm_wmb()     __asm__ __volatile__ ("sfence"::: "memory")
  46 #define cmm_smp_rmb() cmm_barrier()
  47 #define cmm_smp_wmb() cmm_barrier()
  48 #else
  49 /*
  50  * We leave smp_rmb/smp_wmb as full barriers for processors that do not have
  51  * fence instructions.
  52  *
  53  * An empty cmm_smp_rmb() may not be enough on old PentiumPro multiprocessor
  54  * systems, due to an erratum.  The Linux kernel says that "Even distro
  55  * kernels should think twice before enabling this", but for now let's
  56  * be conservative and leave the full barrier on 32-bit processors.  Also,
  57  * IDT WinChip supports weak store ordering, and the kernel may enable it
  58  * under our feet; cmm_smp_wmb() ceases to be a nop for these processors.
  59  */
  60 #if (CAA_BITS_PER_LONG == 32)
  61 #define cmm_mb()    __asm__ __volatile__ ("lock; addl $0,0(%%esp)":::"memory")
  62 #define cmm_rmb()    __asm__ __volatile__ ("lock; addl $0,0(%%esp)":::"memory")
  63 #define cmm_wmb()    __asm__ __volatile__ ("lock; addl $0,0(%%esp)":::"memory")
  64 #else
  65 #define cmm_mb()    __asm__ __volatile__ ("lock; addl $0,0(%%rsp)":::"memory")
  66 #define cmm_rmb()    __asm__ __volatile__ ("lock; addl $0,0(%%rsp)":::"memory")
  67 #define cmm_wmb()    __asm__ __volatile__ ("lock; addl $0,0(%%rsp)":::"memory")
  68 #endif
  69 #endif
  70
  71 #define caa_cpu_relax() __asm__ __volatile__ ("rep; nop" : : : "memory")
  72
  73 #define HAS_CAA_GET_CYCLES
  74
  75 #define rdtscll(val)                                                      \
  76         do {                                                              \
  77              unsigned int __a, __d;                                       \
  78              __asm__ __volatile__ ("rdtsc" : "=a" (__a), "=d" (__d));     \
  79              (val) = ((unsigned long long)__a)                            \
  80                         | (((unsigned long long)__d) << 32);              \
  81         } while(0)
  82
  83 typedef uint64_t caa_cycles_t;
  84
  85 static inline caa_cycles_t caa_get_cycles(void)
  86 {
  87         caa_cycles_t ret = 0;
  88
  89         rdtscll(ret);
  90         return ret;
  91 }
  92
  93 /*
  94  * On Linux, define the membarrier system call number if not yet available in
  95  * the system headers.
  96  */
  97 #if (defined(__linux__) && !defined(__NR_membarrier))
  98 #if (CAA_BITS_PER_LONG == 32)
  99 #define __NR_membarrier         375
 100 #else
 101 #define __NR_membarrier         324
 102 #endif
 103 #endif
 104
 105 #ifdef __cplusplus
 106 }
 107 #endif
 108
 109 #include <urcu/arch/generic.h>
 110
 111 #endif /* _URCU_ARCH_X86_H */