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
  28 #define _PTHREAD_MTX_OPT_PSHARED 0x010
  29 #define _PTHREAD_MTX_OPT_NOTIFY 0x1000  /* notify to drop mutex handling in cvwait */
  30 #define _PTHREAD_MTX_OPT_MUTEX  0x2000 /* this is a mutex type  */
  31
  32
  33 #define PTHRW_COUNT_SHIFT       8
  34 #define PTHRW_INC               (1 << PTHRW_COUNT_SHIFT)
  35 #define PTHRW_BIT_MASK          ((1 << PTHRW_COUNT_SHIFT) - 1)
  36 #define PTHRW_COUNT_MASK        ((uint32_t)~PTHRW_BIT_MASK)
  37 #define PTHRW_MAX_READERS       PTHRW_COUNT_MASK
  38
  39 // L word
  40 #define PTH_RWL_KBIT            0x01    // cannot acquire in user mode
  41 #define PTH_RWL_EBIT            0x02    // exclusive lock in progress
  42 #define PTH_RWL_WBIT            0x04    // write waiters pending in kernel
  43 #define PTH_RWL_PBIT            0x04    // prepost (cv) pending in kernel
  44
  45 #define PTH_RWL_MTX_WAIT        0x20    // in cvar in mutex wait
  46 #define PTH_RWL_RBIT            0x40    // reader pending in kernel (not used)
  47 #define PTH_RWL_MBIT            0x40    // overlapping grants from kernel
  48 #define PTH_RWL_IBIT            0x80    // lock reset, held until first successful unlock
  49
  50 #define PTHRW_RWL_INIT          PTH_RWL_IBIT    // reset on the lock bits (U)
  51 #define PTHRW_RWLOCK_INIT       (PTH_RWL_IBIT | PTH_RWL_RBIT)   // reset on the lock bits (U)
  52 #define PTH_RWLOCK_RESET_RBIT   ((uint32_t)~PTH_RWL_RBIT)
  53
  54 // S word
  55 #define PTH_RWS_SBIT            0x01    // kernel transition seq not set yet
  56 #define PTH_RWS_IBIT            0x02    // Sequence is not set on return from kernel
  57
  58 #define PTH_RWS_CV_CBIT         PTH_RWS_SBIT    // kernel has cleared all info w.r.s.t CV
  59 #define PTH_RWS_CV_PBIT         PTH_RWS_IBIT    // kernel has prepost/fake structs only,no waiters
  60 #define PTH_RWS_CV_BITSALL      (PTH_RWS_CV_CBIT | PTH_RWS_CV_PBIT)
  61 #define PTH_RWS_CV_MBIT         PTH_RWL_MBIT    // to indicate prepost return from kernel
  62 #define PTH_RWS_CV_RESET_PBIT   ((uint32_t)~PTH_RWS_CV_PBIT)
  63
  64 #define PTH_RWS_WSVBIT          0x04    // save W bit
  65
  66 #define PTHRW_RWS_SAVEMASK      (PTH_RWS_WSVBIT)        // save bits mask
  67
  68 #define PTHRW_RWS_INIT          PTH_RWS_SBIT    // reset on the lock bits (U)
  69 #define PTHRW_SW_Reset_BIT_MASK (PTHRW_BIT_MASK & ~PTH_RWS_SBIT)        // All bits except the S bit
  70
  71 // rw_flags
  72 #define PTHRW_KERN_PROCESS_SHARED       0x10
  73 #define PTHRW_KERN_PROCESS_PRIVATE      0x20
  74
  75 #define PTHREAD_MTX_TID_SWITCHING (uint64_t)-1
  76
  77 // L word tests
  78 #define can_rwl_readinuser(x) (((x) & (PTH_RWL_WBIT | PTH_RWL_KBIT)) == 0)
  79 #define is_rwl_ebit_set(x) (((x) & PTH_RWL_EBIT) != 0)
  80 #define is_rwl_wbit_set(x) (((x) & PTH_RWL_WBIT) != 0)
  81 #define is_rwl_ebit_clear(x) (((x) & PTH_RWL_EBIT) == 0)
  82 #define is_rwl_readoverlap(x) (((x) & PTH_RWL_MBIT) != 0)
  83
  84 // S word tests
  85 #define is_rws_setseq(x) (((x) & PTH_RWS_SBIT))
  86 #define is_rws_setunlockinit(x) (((x) & PTH_RWS_IBIT))
  87
  88 static inline int
  89 is_seqlower(uint32_t x, uint32_t y)
  90 {
  91         x &= PTHRW_COUNT_MASK;
  92         y &= PTHRW_COUNT_MASK;
  93         if (x < y) {
  94                 return ((y - x) < (PTHRW_MAX_READERS / 2));
  95         } else {
  96                 return ((x - y) > (PTHRW_MAX_READERS / 2));
  97         }
  98 }
  99
 100 static inline int
 101 is_seqlower_eq(uint32_t x, uint32_t y)
 102 {
 103         if ((x & PTHRW_COUNT_MASK) == (y & PTHRW_COUNT_MASK)) {
 104                 return 1;
 105         } else {
 106                 return is_seqlower(x, y);
 107         }
 108 }
 109
 110 static inline int
 111 is_seqhigher(uint32_t x, uint32_t y)
 112 {
 113         x &= PTHRW_COUNT_MASK;
 114         y &= PTHRW_COUNT_MASK;
 115         if (x > y) {
 116                 return ((x - y) < (PTHRW_MAX_READERS / 2));
 117         } else {
 118                 return ((y - x) > (PTHRW_MAX_READERS / 2));
 119         }
 120 }
 121
 122 static inline int
 123 is_seqhigher_eq(uint32_t x, uint32_t y)
 124 {
 125         if ((x & PTHRW_COUNT_MASK) == (y & PTHRW_COUNT_MASK)) {
 126                 return 1;
 127         } else {
 128                 return is_seqhigher(x,y);
 129         }
 130 }
 131
 132 static inline int
 133 diff_genseq(uint32_t x, uint32_t y)
 134 {
 135         x &= PTHRW_COUNT_MASK;
 136         y &= PTHRW_COUNT_MASK;
 137         if (x == y) {
 138                 return 0;
 139         } else if (x > y)  {
 140                 return x - y;
 141         } else {
 142                 return ((PTHRW_MAX_READERS - y) + x + PTHRW_INC);
 143         }
 144 }
 145
 146 static inline int
 147 find_diff(uint32_t upto, uint32_t lowest)
 148 {
 149         uint32_t diff;
 150
 151         if (upto == lowest)
 152                 return(0);
 153 #if 0
 154         diff = diff_genseq(upto, lowest);
 155 #else
 156         if (is_seqlower(upto, lowest) != 0)
 157                 diff = diff_genseq(lowest, upto);
 158         else
 159                 diff = diff_genseq(upto, lowest);
 160 #endif
 161         diff = (diff >> PTHRW_COUNT_SHIFT);
 162         return(diff);
 163 }
 164
 165 #endif /* __SYNCH_INTERNAL_H__ */