sysdeps/unix/sysv/linux/x86_64/lowlevellock.h

   1 /* Copyright (C) 2002-2017 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _LOWLEVELLOCK_H
  20 #define _LOWLEVELLOCK_H 1
  21
  22 #include <stap-probe.h>
  23
  24 #ifndef __ASSEMBLER__
  25 # include <time.h>
  26 # include <sys/param.h>
  27 # include <bits/pthreadtypes.h>
  28 # include <kernel-features.h>
  29 # include <tcb-offsets.h>
  30
  31 # ifndef LOCK_INSTR
  32 #  ifdef UP
  33 #   define LOCK_INSTR   /* nothing */
  34 #  else
  35 #   define LOCK_INSTR "lock;"
  36 #  endif
  37 # endif
  38 #else
  39 # ifndef LOCK
  40 #  ifdef UP
  41 #   define LOCK
  42 #  else
  43 #   define LOCK lock
  44 #  endif
  45 # endif
  46 #endif
  47
  48 #include <lowlevellock-futex.h>
  49
  50 /* XXX Remove when no assembler code uses futexes anymore.  */
  51 #define SYS_futex               __NR_futex
  52
  53 #ifndef __ASSEMBLER__
  54
  55 /* Initializer for lock.  */
  56 #define LLL_LOCK_INITIALIZER            (0)
  57 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
  58 #define LLL_LOCK_INITIALIZER_WAITERS    (2)
  59
  60
  61 /* NB: in the lll_trylock macro we simply return the value in %eax
  62    after the cmpxchg instruction.  In case the operation succeded this
  63    value is zero.  In case the operation failed, the cmpxchg instruction
  64    has loaded the current value of the memory work which is guaranteed
  65    to be nonzero.  */
  66 #if !IS_IN (libc) || defined UP
  67 # define __lll_trylock_asm LOCK_INSTR "cmpxchgl %2, %1"
  68 #else
  69 # define __lll_trylock_asm "cmpl $0, __libc_multiple_threads(%%rip)\n\t"      \
  70                            "je 0f\n\t"                                        \
  71                            "lock; cmpxchgl %2, %1\n\t"                        \
  72                            "jmp 1f\n\t"                                       \
  73                            "0:\tcmpxchgl %2, %1\n\t"                          \
  74                            "1:"
  75 #endif
  76
  77 #define lll_trylock(futex) \
  78   ({ int ret;                                                                 \
  79      __asm __volatile (__lll_trylock_asm                                      \
  80                        : "=a" (ret), "=m" (futex)                             \
  81                        : "r" (LLL_LOCK_INITIALIZER_LOCKED), "m" (futex),      \
  82                          "0" (LLL_LOCK_INITIALIZER)                           \
  83                        : "memory");                                           \
  84      ret; })
  85
  86 #define lll_cond_trylock(futex) \
  87   ({ int ret;                                                                 \
  88      __asm __volatile (LOCK_INSTR "cmpxchgl %2, %1"                           \
  89                        : "=a" (ret), "=m" (futex)                             \
  90                        : "r" (LLL_LOCK_INITIALIZER_WAITERS),                  \
  91                          "m" (futex), "0" (LLL_LOCK_INITIALIZER)              \
  92                        : "memory");                                           \
  93      ret; })
  94
  95 #if !IS_IN (libc) || defined UP
  96 # define __lll_lock_asm_start LOCK_INSTR "cmpxchgl %4, %2\n\t"                \
  97                               "jz 24f\n\t"
  98 #else
  99 # define __lll_lock_asm_start "cmpl $0, __libc_multiple_threads(%%rip)\n\t"   \
 100                               "je 0f\n\t"                                     \
 101                               "lock; cmpxchgl %4, %2\n\t"                     \
 102                               "jnz 1f\n\t"                                    \
 103                               "jmp 24f\n"                                     \
 104                               "0:\tcmpxchgl %4, %2\n\t"                       \
 105                               "jz 24f\n\t"
 106 #endif
 107
 108 #define lll_lock(futex, private) \
 109   (void)                                                                      \
 110     ({ int ignore1, ignore2, ignore3;                                         \
 111        if (__builtin_constant_p (private) && (private) == LLL_PRIVATE)        \
 112          __asm __volatile (__lll_lock_asm_start                               \
 113                            "1:\tlea %2, %%" RDI_LP "\n"                       \
 114                            "2:\tsub $128, %%" RSP_LP "\n"                     \
 115                            ".cfi_adjust_cfa_offset 128\n"                     \
 116                            "3:\tcallq __lll_lock_wait_private\n"              \
 117                            "4:\tadd $128, %%" RSP_LP "\n"                     \
 118                            ".cfi_adjust_cfa_offset -128\n"                    \
 119                            "24:"                                              \
 120                            : "=S" (ignore1), "=&D" (ignore2), "=m" (futex),   \
 121                              "=a" (ignore3)                                   \
 122                            : "0" (1), "m" (futex), "3" (0)                    \
 123                            : "cx", "r11", "cc", "memory");                    \
 124        else                                                                   \
 125          __asm __volatile (__lll_lock_asm_start                               \
 126                            "1:\tlea %2, %%" RDI_LP "\n"                       \
 127                            "2:\tsub $128, %%" RSP_LP "\n"                     \
 128                            ".cfi_adjust_cfa_offset 128\n"                     \
 129                            "3:\tcallq __lll_lock_wait\n"                      \
 130                            "4:\tadd $128, %%" RSP_LP "\n"                     \
 131                            ".cfi_adjust_cfa_offset -128\n"                    \
 132                            "24:"                                              \
 133                            : "=S" (ignore1), "=D" (ignore2), "=m" (futex),    \
 134                              "=a" (ignore3)                                   \
 135                            : "1" (1), "m" (futex), "3" (0), "0" (private)     \
 136                            : "cx", "r11", "cc", "memory");                    \
 137     })                                                                        \
 138
 139 #define lll_cond_lock(futex, private) \
 140   (void)                                                                      \
 141     ({ int ignore1, ignore2, ignore3;                                         \
 142        __asm __volatile (LOCK_INSTR "cmpxchgl %4, %2\n\t"                     \
 143                          "jz 24f\n"                                           \
 144                          "1:\tlea %2, %%" RDI_LP "\n"                         \
 145                          "2:\tsub $128, %%" RSP_LP "\n"                       \
 146                          ".cfi_adjust_cfa_offset 128\n"                       \
 147                          "3:\tcallq __lll_lock_wait\n"                        \
 148                          "4:\tadd $128, %%" RSP_LP "\n"                       \
 149                          ".cfi_adjust_cfa_offset -128\n"                      \
 150                          "24:"                                                \
 151                          : "=S" (ignore1), "=D" (ignore2), "=m" (futex),      \
 152                            "=a" (ignore3)                                     \
 153                          : "1" (2), "m" (futex), "3" (0), "0" (private)       \
 154                          : "cx", "r11", "cc", "memory");                      \
 155     })
 156
 157 #define lll_timedlock(futex, timeout, private) \
 158   ({ int result, ignore1, ignore2, ignore3;                                   \
 159      __asm __volatile (LOCK_INSTR "cmpxchgl %1, %4\n\t"                       \
 160                        "jz 24f\n"                                             \
 161                        "1:\tlea %4, %%" RDI_LP "\n"                           \
 162                        "0:\tmov %8, %%" RDX_LP "\n"                           \
 163                        "2:\tsub $128, %%" RSP_LP "\n"                         \
 164                        ".cfi_adjust_cfa_offset 128\n"                         \
 165                        "3:\tcallq __lll_timedlock_wait\n"                     \
 166                        "4:\tadd $128, %%" RSP_LP "\n"                         \
 167                        ".cfi_adjust_cfa_offset -128\n"                        \
 168                        "24:"                                                  \
 169                        : "=a" (result), "=D" (ignore1), "=S" (ignore2),       \
 170                          "=&d" (ignore3), "=m" (futex)                        \
 171                        : "0" (0), "1" (1), "m" (futex), "m" (timeout),        \
 172                          "2" (private)                                        \
 173                        : "memory", "cx", "cc", "r10", "r11");                 \
 174      result; })
 175
 176 extern int __lll_timedlock_elision (int *futex, short *adapt_count,
 177                                          const struct timespec *timeout,
 178                                          int private) attribute_hidden;
 179
 180 #define lll_timedlock_elision(futex, adapt_count, timeout, private)     \
 181   __lll_timedlock_elision(&(futex), &(adapt_count), timeout, private)
 182
 183 #if !IS_IN (libc) || defined UP
 184 # define __lll_unlock_asm_start LOCK_INSTR "decl %0\n\t"                      \
 185                                 "je 24f\n\t"
 186 #else
 187 # define __lll_unlock_asm_start "cmpl $0, __libc_multiple_threads(%%rip)\n\t" \
 188                                 "je 0f\n\t"                                   \
 189                                 "lock; decl %0\n\t"                           \
 190                                 "jne 1f\n\t"                                  \
 191                                 "jmp 24f\n\t"                                 \
 192                                 "0:\tdecl %0\n\t"                             \
 193                                 "je 24f\n\t"
 194 #endif
 195
 196 #define lll_unlock(futex, private) \
 197   (void)                                                                      \
 198     ({ int ignore;                                                            \
 199        if (__builtin_constant_p (private) && (private) == LLL_PRIVATE)        \
 200          __asm __volatile (__lll_unlock_asm_start                             \
 201                            "1:\tlea %0, %%" RDI_LP "\n"                       \
 202                            "2:\tsub $128, %%" RSP_LP "\n"                     \
 203                            ".cfi_adjust_cfa_offset 128\n"                     \
 204                            "3:\tcallq __lll_unlock_wake_private\n"            \
 205                            "4:\tadd $128, %%" RSP_LP "\n"                     \
 206                            ".cfi_adjust_cfa_offset -128\n"                    \
 207                            "24:"                                              \
 208                            : "=m" (futex), "=&D" (ignore)                     \
 209                            : "m" (futex)                                      \
 210                            : "ax", "cx", "r11", "cc", "memory");              \
 211        else                                                                   \
 212          __asm __volatile (__lll_unlock_asm_start                             \
 213                            "1:\tlea %0, %%" RDI_LP "\n"                       \
 214                            "2:\tsub $128, %%" RSP_LP "\n"                     \
 215                            ".cfi_adjust_cfa_offset 128\n"                     \
 216                            "3:\tcallq __lll_unlock_wake\n"                    \
 217                            "4:\tadd $128, %%" RSP_LP "\n"                     \
 218                            ".cfi_adjust_cfa_offset -128\n"                    \
 219                            "24:"                                              \
 220                            : "=m" (futex), "=&D" (ignore)                     \
 221                            : "m" (futex), "S" (private)                       \
 222                            : "ax", "cx", "r11", "cc", "memory");              \
 223     })
 224
 225 #define lll_islocked(futex) \
 226   (futex != LLL_LOCK_INITIALIZER)
 227
 228
 229 /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
 230    wake-up when the clone terminates.  The memory location contains the
 231    thread ID while the clone is running and is reset to zero by the kernel
 232    afterwards.  The kernel up to version 3.16.3 does not use the private futex
 233    operations for futex wake-up when the clone terminates.  */
 234 #define lll_wait_tid(tid) \
 235   do {                                  \
 236     __typeof (tid) __tid;               \
 237     while ((__tid = (tid)) != 0)        \
 238       lll_futex_wait (&(tid), __tid, LLL_SHARED);\
 239   } while (0)
 240
 241 extern int __lll_timedwait_tid (int *, const struct timespec *)
 242      attribute_hidden;
 243
 244 /* As lll_wait_tid, but with a timeout.  If the timeout occurs then return
 245    ETIMEDOUT.  If ABSTIME is invalid, return EINVAL.
 246    XXX Note that this differs from the generic version in that we do the
 247    error checking here and not in __lll_timedwait_tid.  */
 248 #define lll_timedwait_tid(tid, abstime) \
 249   ({                                                                          \
 250     int __result = 0;                                                         \
 251     if ((tid) != 0)                                                           \
 252       __result = __lll_timedwait_tid (&(tid), (abstime));                     \
 253     __result; })
 254
 255 extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
 256   attribute_hidden;
 257
 258 extern int __lll_unlock_elision (int *lock, int private)
 259   attribute_hidden;
 260
 261 extern int __lll_trylock_elision (int *lock, short *adapt_count)
 262   attribute_hidden;
 263
 264 #define lll_lock_elision(futex, adapt_count, private) \
 265   __lll_lock_elision (&(futex), &(adapt_count), private)
 266 #define lll_unlock_elision(futex, adapt_count, private) \
 267   __lll_unlock_elision (&(futex), private)
 268 #define lll_trylock_elision(futex, adapt_count) \
 269   __lll_trylock_elision (&(futex), &(adapt_count))
 270
 271 #endif  /* !__ASSEMBLER__ */
 272
 273 #endif  /* lowlevellock.h */