lib/libpthread/arch/i386/pthread_md.h

   1 /*      $NetBSD: pthread_md.h,v 1.16 2009/03/29 09:30:05 ad Exp $       */
   2
   3 /*-
   4  * Copyright (c) 2001, 2007, 2008 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Nathan J. Williams, and by Andrew Doran.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #ifndef _LIB_PTHREAD_I386_MD_H
  33 #define _LIB_PTHREAD_I386_MD_H
  34
  35 #include <sys/ucontext.h>
  36 #include <ucontext.h>
  37
  38 static inline long
  39 pthread__sp(void)
  40 {
  41         long ret;
  42         __asm("movl %%esp, %0" : "=g" (ret));
  43
  44         return ret;
  45 }
  46
  47 #define pthread__uc_sp(ucp) ((ucp)->uc_mcontext.__gregs[_REG_UESP])
  48
  49 /*
  50  * Set initial, sane values for registers whose values aren't just
  51  * "don't care".
  52  *
  53  * We use the current context instead of a guessed one because we cannot
  54  * assume how the GDT entries are ordered:  what is true on i386 is not
  55  * true anymore on amd64.
  56  */
  57 #define _INITCONTEXT_U_MD(ucp)                                          \
  58         do {                                                            \
  59                 ucontext_t ucur;                                        \
  60                 (void)getcontext(&ucur);                                \
  61                 (ucp)->uc_mcontext.__gregs[_REG_GS] =                   \
  62                     ucur.uc_mcontext.__gregs[_REG_GS],                  \
  63                 (ucp)->uc_mcontext.__gregs[_REG_FS] =                   \
  64                     ucur.uc_mcontext.__gregs[_REG_FS],                  \
  65                 (ucp)->uc_mcontext.__gregs[_REG_ES] =                   \
  66                     ucur.uc_mcontext.__gregs[_REG_ES],                  \
  67                 (ucp)->uc_mcontext.__gregs[_REG_DS] =                   \
  68                     ucur.uc_mcontext.__gregs[_REG_DS],                  \
  69                 (ucp)->uc_mcontext.__gregs[_REG_CS] =                   \
  70                     ucur.uc_mcontext.__gregs[_REG_CS],                  \
  71                 (ucp)->uc_mcontext.__gregs[_REG_SS] =                   \
  72                     ucur.uc_mcontext.__gregs[_REG_SS],                  \
  73                 (ucp)->uc_mcontext.__gregs[_REG_EFL] =                  \
  74                     ucur.uc_mcontext.__gregs[_REG_EFL];                 \
  75         } while (/*CONSTCOND*/0);
  76
  77 #define pthread__smt_pause()    __asm __volatile("rep; nop" ::: "memory")
  78 /*      #define PTHREAD__HAVE_THREADREG */
  79
  80 /* Don't need additional memory barriers. */
  81 #define PTHREAD__ATOMIC_IS_MEMBAR
  82
  83 static inline pthread_t
  84 #ifdef __GNUC__
  85 __attribute__ ((__const__))
  86 #endif
  87 pthread__threadreg_get(void)
  88 {
  89         pthread_t self;
  90
  91         __asm volatile("movl %%gs:0, %0"
  92                 : "=r" (self)
  93                 :);
  94
  95         return self;
  96 }
  97
  98 static inline void *
  99 _atomic_cas_ptr(volatile void *ptr, void *old, void *new)
 100 {
 101         volatile uintptr_t *cast = ptr;
 102         void *ret;
 103
 104         __asm __volatile ("lock; cmpxchgl %2, %1"
 105                 : "=a" (ret), "=m" (*cast)
 106                 : "r" (new), "m" (*cast), "0" (old));
 107
 108         return ret;
 109 }
 110
 111 static inline void *
 112 _atomic_cas_ptr_ni(volatile void *ptr, void *old, void *new)
 113 {
 114         volatile uintptr_t *cast = ptr;
 115         void *ret;
 116
 117         __asm __volatile ("cmpxchgl %2, %1"
 118                 : "=a" (ret), "=m" (*cast)
 119                 : "r" (new), "m" (*cast), "0" (old));
 120
 121         return ret;
 122 }
 123
 124 #endif /* _LIB_PTHREAD_I386_MD_H */