glibc/sysdeps/loongarch/nptl/tls.h

/* Definition for thread-local data handling.
   Copyright (C) 2022-2023 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library.  If not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _LOONGARCH_TLS_H
#define _LOONGARCH_TLS_H 1

#include <dl-sysdep.h>

#ifndef __ASSEMBLER__
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <dl-dtv.h>

register void *__thread_self asm ("$tp");
#define READ_THREAD_POINTER() ({ __thread_self; })

/* Get system call information.  */
#include <sysdep.h>

/* The TP points to the start of the thread blocks.  */
#define TLS_DTV_AT_TP 1
#define TLS_TCB_AT_TP 0

/* Get the thread descriptor definition.  */
#include <nptl/descr.h>

typedef struct
{
  dtv_t *dtv;
  void *private;
} tcbhead_t;

/* This is the size of the initial TCB.  Because our TCB is before the thread
   pointer, we don't need this.  */
#define TLS_INIT_TCB_SIZE 0

/* Alignment requirements for the initial TCB.  */
#define TLS_INIT_TCB_ALIGN __alignof__(struct pthread)

/* This is the size of the TCB.  Because our TCB is before the thread
   pointer, we don't need this.  */
#define TLS_TCB_SIZE 0

/* Alignment requirements for the TCB.  */
#define TLS_TCB_ALIGN __alignof__(struct pthread)

/* This is the size we need before TCB - actually, it includes the TCB.  */
#define TLS_PRE_TCB_SIZE \
  (sizeof (struct pthread) \
   + ((sizeof (tcbhead_t) + TLS_TCB_ALIGN - 1) & ~(TLS_TCB_ALIGN - 1)))

/* The thread pointer tp points to the end of the TCB.
   The pthread_descr structure is immediately in front of the TCB.  */
#define TLS_TCB_OFFSET 0

/* Install the dtv pointer.  The pointer passed is to the element with
   index -1 which contain the length.  */
#define INSTALL_DTV(tcbp, dtvp) (((tcbhead_t *) (tcbp))[-1].dtv = (dtvp) + 1)

/* Install new dtv for current thread.  */
#define INSTALL_NEW_DTV(dtv) (THREAD_DTV () = (dtv))

/* Return dtv of given thread descriptor.  */
#define GET_DTV(tcbp) (((tcbhead_t *) (tcbp))[-1].dtv)

/* Code to initially initialize the thread pointer.  */
#define TLS_INIT_TP(tcbp) \
  ({ \
    __thread_self = (char *) tcbp + TLS_TCB_OFFSET; \
    true; \
  })

/* Return the address of the dtv for the current thread.  */
#define THREAD_DTV() \
  (((tcbhead_t *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET))[-1].dtv)

/* Return the thread descriptor for the current thread.  */
#define THREAD_SELF \
  ((struct pthread *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET \
		       - TLS_PRE_TCB_SIZE))

/* Value passed to 'clone' for initialization of the thread register.  */
#define TLS_DEFINE_INIT_TP(tp, pd) \
  void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE

/* Informs libthread_db that the thread pointer is register 2, which is used
 * to know how to do THREAD_SELF.  */
#define DB_THREAD_SELF \
  REGISTER (64, 64, 2 * 8, -TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE)

/* Access to data in the thread descriptor is easy.  */
# include <tcb-access.h>

/* l_tls_offset == 0 is perfectly valid, so we have to use some different
   value to mean unset l_tls_offset.  */
#define NO_TLS_OFFSET -1

/* Get and set the global scope generation counter in struct pthread.  */
#define THREAD_GSCOPE_IN_TCB 1
#define THREAD_GSCOPE_FLAG_UNUSED 0
#define THREAD_GSCOPE_FLAG_USED 1
#define THREAD_GSCOPE_FLAG_WAIT 2
#define THREAD_GSCOPE_RESET_FLAG() \
  do \
    { \
      int __res = atomic_exchange_release (&THREAD_SELF->header.gscope_flag, \
					   THREAD_GSCOPE_FLAG_UNUSED); \
      if (__res == THREAD_GSCOPE_FLAG_WAIT) \
	lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); \
    } \
  while (0)
#define THREAD_GSCOPE_SET_FLAG() \
  do \
    { \
      THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED; \
      atomic_write_barrier (); \
    } \
  while (0)

#endif /* __ASSEMBLER__ */

#endif /* tls.h */