1  /* Copyright (C) 2005-2023 Free Software Foundation, Inc.
       2  
       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 License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     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.  */
      50  # define TLS_INIT_TCB_SIZE	sizeof (tcbhead_t)
      51  
      52  /* This is the size of the TCB.  */
      53  # define TLS_TCB_SIZE		sizeof (tcbhead_t)
      54  
      55  /* This is the size we need before TCB.  */
      56  # define TLS_PRE_TCB_SIZE	sizeof (struct pthread)
      57  
      58  /* Install the dtv pointer.  The pointer passed is to the element with
      59     index -1 which contain the length.  */
      60  # define INSTALL_DTV(tcbp, dtvp) \
      61    (((tcbhead_t *) (tcbp))->dtv = (dtvp) + 1)
      62  
      63  /* Install new dtv for current thread.  */
      64  # define INSTALL_NEW_DTV(dtv) \
      65    (THREAD_DTV() = (dtv))
      66  
      67  /* Return dtv of given thread descriptor.  */
      68  # define GET_DTV(tcbp) \
      69    (((tcbhead_t *) (tcbp))->dtv)
      70  
      71  /* Code to initially initialize the thread pointer.  This might need
      72     special attention since 'errno' is not yet available and if the
      73     operation can cause a failure 'errno' must not be touched.  */
      74  # define TLS_INIT_TP(tcbp) \
      75    ({ __asm __volatile ("msr tpidr_el0, %0" : : "r" (tcbp)); true; })
      76  
      77  /* Value passed to 'clone' for initialization of the thread register.  */
      78  # define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd) + 1
      79  
      80  /* Return the address of the dtv for the current thread.  */
      81  # define THREAD_DTV() \
      82    (((tcbhead_t *) __builtin_thread_pointer ())->dtv)
      83  
      84  /* Return the thread descriptor for the current thread.  */
      85  # define THREAD_SELF \
      86   ((struct pthread *)__builtin_thread_pointer () - 1)
      87  
      88  /* Magic for libthread_db to know how to do THREAD_SELF.  */
      89  # define DB_THREAD_SELF \
      90    CONST_THREAD_AREA (64, sizeof (struct pthread))
      91  
      92  # include <tcb-access.h>
      93  
      94  /* Get and set the global scope generation counter in struct pthread.  */
      95  # define THREAD_GSCOPE_FLAG_UNUSED 0
      96  # define THREAD_GSCOPE_FLAG_USED   1
      97  # define THREAD_GSCOPE_FLAG_WAIT   2
      98  # define THREAD_GSCOPE_RESET_FLAG() \
      99    do									     \
     100      { int __res								     \
     101  	= atomic_exchange_release (&THREAD_SELF->header.gscope_flag,	     \
     102  			       THREAD_GSCOPE_FLAG_UNUSED);		     \
     103        if (__res == THREAD_GSCOPE_FLAG_WAIT)				     \
     104  	lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);   \
     105      }									     \
     106    while (0)
     107  # define THREAD_GSCOPE_SET_FLAG() \
     108    do									     \
     109      {									     \
     110        THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED;	     \
     111        atomic_write_barrier ();						     \
     112      }									     \
     113    while (0)
     114  
     115  # endif /* __ASSEMBLER__ */
     116  
     117  #endif	/* tls.h */