kern/synch_internal.h

   1 /*
   2  * Copyright (c) 2000-2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #ifndef __SYNCH_INTERNAL_H__
  25 #define __SYNCH_INTERNAL_H__
  26
  27 // kwe_state
  28 enum {
  29         KWE_THREAD_INWAIT = 1,
  30         KWE_THREAD_PREPOST,
  31         KWE_THREAD_BROADCAST,
  32 };
  33
  34 #define _PTHREAD_MTX_OPT_PSHARED 0x010
  35 #define _PTHREAD_MTX_OPT_NOTIFY 0x1000  /* notify to drop mutex handling in cvwait */
  36 #define _PTHREAD_MTX_OPT_MUTEX  0x2000 /* this is a mutex type  */
  37
  38
  39 #define PTHRW_COUNT_SHIFT       8
  40 #define PTHRW_INC               (1 << PTHRW_COUNT_SHIFT)
  41 #define PTHRW_BIT_MASK          ((1 << PTHRW_COUNT_SHIFT) - 1)
  42 #define PTHRW_COUNT_MASK        ((uint32_t)~PTHRW_BIT_MASK)
  43 #define PTHRW_MAX_READERS       PTHRW_COUNT_MASK
  44
  45 // L word
  46 #define PTH_RWL_KBIT            0x01    // cannot acquire in user mode
  47 #define PTH_RWL_EBIT            0x02    // exclusive lock in progress
  48 #define PTH_RWL_WBIT            0x04    // write waiters pending in kernel
  49 #define PTH_RWL_PBIT            0x04    // prepost (cv) pending in kernel
  50
  51 #define PTH_RWL_MTX_WAIT        0x20    // in cvar in mutex wait
  52 #define PTH_RWL_UBIT            0x40    // lock is unlocked (no readers or writers)
  53 #define PTH_RWL_MBIT            0x40    // overlapping grants from kernel (only in updateval)
  54 #define PTH_RWL_IBIT            0x80    // lock reset, held until first successful unlock
  55
  56 #define PTHRW_RWL_INIT          PTH_RWL_IBIT    // reset on the lock bits (U)
  57 #define PTHRW_RWLOCK_INIT       (PTH_RWL_IBIT | PTH_RWL_UBIT)   // reset on the lock bits (U)
  58
  59 // S word
  60 #define PTH_RWS_SBIT            0x01    // kernel transition seq not set yet
  61 #define PTH_RWS_IBIT            0x02    // Sequence is not set on return from kernel
  62
  63 #define PTH_RWS_CV_CBIT         PTH_RWS_SBIT    // kernel has cleared all info w.r.s.t CV
  64 #define PTH_RWS_CV_PBIT         PTH_RWS_IBIT    // kernel has prepost/fake structs only,no waiters
  65 #define PTH_RWS_CV_BITSALL      (PTH_RWS_CV_CBIT | PTH_RWS_CV_PBIT)
  66 #define PTH_RWS_CV_MBIT         PTH_RWL_MBIT    // to indicate prepost return from kernel
  67 #define PTH_RWS_CV_RESET_PBIT   ((uint32_t)~PTH_RWS_CV_PBIT)
  68
  69 #define PTH_RWS_WSVBIT          0x04    // save W bit
  70
  71 #define PTHRW_RWS_SAVEMASK      (PTH_RWS_WSVBIT)        // save bits mask
  72
  73 #define PTHRW_RWS_INIT          PTH_RWS_SBIT    // reset on the lock bits (U)
  74
  75 // rw_flags
  76 #define PTHRW_KERN_PROCESS_SHARED       0x10
  77 #define PTHRW_KERN_PROCESS_PRIVATE      0x20
  78
  79 #define PTHREAD_MTX_TID_SWITCHING (uint64_t)-1
  80
  81 // L word tests
  82 #define is_rwl_ebit_set(x) (((x) & PTH_RWL_EBIT) != 0)
  83 #define is_rwl_wbit_set(x) (((x) & PTH_RWL_WBIT) != 0)
  84 #define is_rwl_ebit_clear(x) (((x) & PTH_RWL_EBIT) == 0)
  85 #define is_rwl_readoverlap(x) (((x) & PTH_RWL_MBIT) != 0)
  86
  87 // S word tests
  88 #define is_rws_sbit_set(x) (((x) & PTH_RWS_SBIT) != 0)
  89 #define is_rws_unlockinit_set(x) (((x) & PTH_RWS_IBIT) != 0)
  90 #define is_rws_savemask_set(x) (((x) & PTHRW_RWS_SAVEMASK) != 0)
  91 #define is_rws_pbit_set(x) (((x) & PTH_RWS_CV_PBIT) != 0)
  92
  93 // kwe_flags
  94 #define KWE_FLAG_LOCKPREPOST    0x1 // cvwait caused a lock prepost
  95
  96 static inline int
  97 is_seqlower(uint32_t x, uint32_t y)
  98 {
  99         x &= PTHRW_COUNT_MASK;
 100         y &= PTHRW_COUNT_MASK;
 101         if (x < y) {
 102                 return ((y - x) < (PTHRW_MAX_READERS / 2));
 103         } else {
 104                 return ((x - y) > (PTHRW_MAX_READERS / 2));
 105         }
 106 }
 107
 108 static inline int
 109 is_seqlower_eq(uint32_t x, uint32_t y)
 110 {
 111         if ((x & PTHRW_COUNT_MASK) == (y & PTHRW_COUNT_MASK)) {
 112                 return 1;
 113         } else {
 114                 return is_seqlower(x, y);
 115         }
 116 }
 117
 118 static inline int
 119 is_seqhigher(uint32_t x, uint32_t y)
 120 {
 121         x &= PTHRW_COUNT_MASK;
 122         y &= PTHRW_COUNT_MASK;
 123         if (x > y) {
 124                 return ((x - y) < (PTHRW_MAX_READERS / 2));
 125         } else {
 126                 return ((y - x) > (PTHRW_MAX_READERS / 2));
 127         }
 128 }
 129
 130 static inline int
 131 is_seqhigher_eq(uint32_t x, uint32_t y)
 132 {
 133         if ((x & PTHRW_COUNT_MASK) == (y & PTHRW_COUNT_MASK)) {
 134                 return 1;
 135         } else {
 136                 return is_seqhigher(x,y);
 137         }
 138 }
 139
 140 static inline int
 141 diff_genseq(uint32_t x, uint32_t y)
 142 {
 143         x &= PTHRW_COUNT_MASK;
 144         y &= PTHRW_COUNT_MASK;
 145         if (x == y) {
 146                 return 0;
 147         } else if (x > y)  {
 148                 return x - y;
 149         } else {
 150                 return ((PTHRW_MAX_READERS - y) + x + PTHRW_INC);
 151         }
 152 }
 153
 154 static inline int
 155 find_diff(uint32_t upto, uint32_t lowest)
 156 {
 157         uint32_t diff;
 158
 159         if (upto == lowest)
 160                 return(0);
 161 #if 0
 162         diff = diff_genseq(upto, lowest);
 163 #else
 164         if (is_seqlower(upto, lowest) != 0)
 165                 diff = diff_genseq(lowest, upto);
 166         else
 167                 diff = diff_genseq(upto, lowest);
 168 #endif
 169         diff = (diff >> PTHRW_COUNT_SHIFT);
 170         return(diff);
 171 }
 172
 173 #endif /* __SYNCH_INTERNAL_H__ */