nptl/sysdeps/unix/sysv/linux/i386/lowlevelsem.h

   1 /* Copyright (C) 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _LOWLEVELSEM_H
  21 #define _LOWLEVELSEM_H  1
  22
  23 #include <dl-sysdep.h>
  24 #include <tls.h>
  25
  26 #ifndef LOCK
  27 # ifdef UP
  28 #  define LOCK  /* nothing */
  29 # else
  30 #  define LOCK "lock;"
  31 # endif
  32 #endif
  33
  34 #define SYS_futex               240
  35
  36
  37 #ifdef I386_USE_SYSENTER
  38 # ifdef SHARED
  39 # define LLL_SEM_ENTER_KERNEL(arg)      "call *%%gs:%P" #arg "\n\t"
  40 # else
  41 # define LLL_SEM_ENTER_KERNEL(arg)      "call *_dl_sysinfo\n\t"
  42 # endif
  43 #else
  44 # define LLL_SEM_ENTER_KERNEL(arg)      "int $0x80\n\t"
  45 #endif
  46
  47 #define lll_sem_wait(sem) \
  48   ({ int result, ignore1, ignore2;                                            \
  49      __asm __volatile ("1:\tincl 8(%4)\n\t"                                   \
  50                        LOCK "incl (%4)\n\t"                                   \
  51                        "jng 2f\n"                                             \
  52                        ".subsection 1\n"                                      \
  53                        "2:\tmovl %4, %%eax\n\t"                               \
  54                        "call __lll_unlock_wake\n\t"                           \
  55                        "jmp 3f\n\t"                                           \
  56                        ".previous\n"                                          \
  57                        "3:\tpushl %%ebx\n\t"                                  \
  58                        "movl %%esi, %%ecx\n\t"                                \
  59                        "movl %%esi, %%edx\n\t"                                \
  60                        "leal 4(%4), %%ebx\n\t"                                \
  61                        "movl %5, %%eax\n\t"                                   \
  62                        LLL_SEM_ENTER_KERNEL (9)                               \
  63                        "movl %%eax, %%edx\n\t"                                \
  64                        "popl %%ebx\n\t"                                       \
  65                        "orl $-1, %%eax\n\t"                                   \
  66                        LOCK "xaddl %%eax, (%4)\n\t"                           \
  67                        "jne 4f\n\t"                                           \
  68                        ".subsection 1\n"                                      \
  69                        "4:\tmovl %4, %%ecx\n\t"                               \
  70                        "call __lll_lock_wait\n\t"                             \
  71                        "jmp 5f\n\t"                                           \
  72                        ".previous\n"                                          \
  73                        "5:\tdecl 8(%4)\n\t"                                   \
  74                        "xorl %0, %0\n\t"                                      \
  75                        "cmpl $0, 4(%4)\n\t"                                   \
  76                        "jne,pt 6f\n\t"                                        \
  77                        "cmpl %7, %%edx\n\t"                                   \
  78                        "jne,pn 1b\n\t"                                        \
  79                        "addl %8, %0\n\t" /* Shorter than movl %7, %0 */       \
  80                        "6:"                                                   \
  81                        : "=a" (result), "=c" (ignore1), "=d" (ignore2),       \
  82                          "=m" (*sem)                                          \
  83                        : "D" (sem), "i" (SYS_futex), "S" (0),                 \
  84                          "i" (-EINTR), "i" (EINTR),                           \
  85                          "i" (offsetof (tcbhead_t, sysinfo)));                \
  86      result; })
  87
  88
  89 extern int __lll_sem_timedwait (struct sem *sem, const struct timespec *ts)
  90      __attribute__ ((regparm (2))) attribute_hidden;
  91 #define lll_sem_timedwait(sem, timeout) \
  92   __lll_sem_timedwait (sem, timeout)
  93
  94
  95 #define lll_sem_post(sem) \
  96   (void) ({ int ignore1, ignore2, ignore3;                                    \
  97             __asm __volatile ("movl $1, %%eax\n\t"                            \
  98                               LOCK                                            \
  99                               "xaddl %%eax, (%4)\n\t"                         \
 100                               "pushl %%esi\n\t"                               \
 101                               "pushl %%ebx\n\t"                               \
 102                               "movl %4, %%ebx\n\t"                            \
 103                               "leal 1(%%eax), %%edx\n\t"                      \
 104                               "xorl %%esi, %%esi\n\t"                         \
 105                               "movl %5, %%eax\n\t"                            \
 106                               /* movl $FUTEX_WAKE, %ecx */                    \
 107                               "movl $1, %%ecx\n\t"                            \
 108                               LLL_SEM_ENTER_KERNEL (6)                        \
 109                               "popl %%ebx\n\t"                                \
 110                               "popl %%esi"                                    \
 111                               : "=&a" (ignore1), "=c" (ignore2),              \
 112                                 "=m" (*sem), "=d" (ignore3)                   \
 113                               : "r" (sem), "i" (SYS_futex),                   \
 114                                 "i" (offsetof (tcbhead_t, sysinfo))); })
 115
 116 #endif  /* lowlevelsem.h */