sysdeps/m68k/nptl/tls.h

   1 /* Definition for thread-local data handling.  NPTL/m68k version.
   2    Copyright (C) 2010-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _TLS_H
  20 #define _TLS_H  1
  21
  22 #include <dl-sysdep.h>
  23
  24 #ifndef __ASSEMBLER__
  25 # include <stdbool.h>
  26 # include <stddef.h>
  27 # include <stdint.h>
  28 # include <dl-dtv.h>
  29 #endif /* __ASSEMBLER__ */
  30
  31 #ifndef __ASSEMBLER__
  32
  33 /* Get system call information.  */
  34 # include <sysdep.h>
  35
  36 /* The TP points to the start of the thread blocks.  */
  37 # define TLS_DTV_AT_TP  1
  38 # define TLS_TCB_AT_TP  0
  39
  40 /* Get the thread descriptor definition.  */
  41 # include <nptl/descr.h>
  42
  43 typedef struct
  44 {
  45   dtv_t *dtv;
  46   void *private;
  47 } tcbhead_t;
  48
  49 /* This is the size of the initial TCB.  Because our TCB is before the thread
  50    pointer, we don't need this.  */
  51 # define TLS_INIT_TCB_SIZE      0
  52
  53 /* This is the size of the TCB.  Because our TCB is before the thread
  54    pointer, we don't need this.  */
  55 # define TLS_TCB_SIZE           0
  56
  57 /* This is the size we need before TCB - actually, it includes the TCB.  */
  58 # define TLS_PRE_TCB_SIZE                                               \
  59   (sizeof (struct pthread)                                              \
  60    + ((sizeof (tcbhead_t) + __alignof (struct pthread) - 1)             \
  61       & ~(__alignof (struct pthread) - 1)))
  62
  63 /* The thread pointer (TP) points to the end of the
  64    TCB + 0x7000, as for PowerPC and MIPS.  This implies that TCB address is
  65    TP - 0x7000.  As we define TLS_DTV_AT_TP we can
  66    assume that the pthread struct is allocated immediately ahead of the
  67    TCB.  This implies that the pthread_descr address is
  68    TP - (TLS_PRE_TCB_SIZE + 0x7000).  */
  69 # define TLS_TCB_OFFSET 0x7000
  70
  71 /* Install the dtv pointer.  The pointer passed is to the element with
  72    index -1 which contain the length.  */
  73 # define INSTALL_DTV(tcbp, dtvp) \
  74   ((tcbhead_t *) (tcbp))[-1].dtv = dtvp + 1
  75
  76 /* Install new dtv for current thread.  */
  77 # define INSTALL_NEW_DTV(dtv) \
  78   (THREAD_DTV () = (dtv))
  79
  80 /* Return dtv of given thread descriptor.  */
  81 # define GET_DTV(tcbp) \
  82   (((tcbhead_t *) (tcbp))[-1].dtv)
  83
  84 /* Code to initially initialize the thread pointer.  This might need
  85    special attention since 'errno' is not yet available and if the
  86    operation can cause a failure 'errno' must not be touched.  */
  87 # define TLS_INIT_TP(tcbp)                                              \
  88   ({                                                                    \
  89     int _sys_result;                                                    \
  90                                                                         \
  91     _sys_result = INTERNAL_SYSCALL_CALL (set_thread_area,               \
  92                                     ((void *) (tcbp)) + TLS_TCB_OFFSET); \
  93     !INTERNAL_SYSCALL_ERROR_P (_sys_result); })
  94
  95 # define TLS_DEFINE_INIT_TP(tp, pd) \
  96   void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE
  97
  98 extern void * __m68k_read_tp (void);
  99
 100 /* Return the address of the dtv for the current thread.  */
 101 # define THREAD_DTV() \
 102   (((tcbhead_t *) (__m68k_read_tp () - TLS_TCB_OFFSET))[-1].dtv)
 103
 104 /* Return the thread descriptor for the current thread.  */
 105 # define THREAD_SELF \
 106   ((struct pthread *) (__m68k_read_tp () - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
 107
 108 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 109 # define DB_THREAD_SELF \
 110   CONST_THREAD_AREA (32, TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE)
 111
 112 # include <tcb-access.h>
 113
 114 /* l_tls_offset == 0 is perfectly valid on M68K, so we have to use some
 115    different value to mean unset l_tls_offset.  */
 116 # define NO_TLS_OFFSET          -1
 117
 118 /* Get and set the global scope generation counter in struct pthread.  */
 119 #define THREAD_GSCOPE_FLAG_UNUSED 0
 120 #define THREAD_GSCOPE_FLAG_USED   1
 121 #define THREAD_GSCOPE_FLAG_WAIT   2
 122 #define THREAD_GSCOPE_RESET_FLAG()                                      \
 123   do                                                                    \
 124     { int __res                                                         \
 125         = atomic_exchange_release (&THREAD_SELF->header.gscope_flag,    \
 126                                THREAD_GSCOPE_FLAG_UNUSED);              \
 127       if (__res == THREAD_GSCOPE_FLAG_WAIT)                             \
 128         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); \
 129     }                                                                   \
 130   while (0)
 131 #define THREAD_GSCOPE_SET_FLAG()                                        \
 132   do                                                                    \
 133     {                                                                   \
 134       THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED;        \
 135       atomic_write_barrier ();                                          \
 136     }                                                                   \
 137   while (0)
 138
 139 #endif /* __ASSEMBLER__ */
 140
 141 #endif  /* tls.h */