glibc/sysdeps/s390/nptl/tls.h

/* Definition for thread-local data handling.  NPTL/s390 version.
   Copyright (C) 2003-2024 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 _TLS_H
#define _TLS_H	1

#include <dl-sysdep.h>
#ifndef __ASSEMBLER__
# include <stdbool.h>
# include <stddef.h>
# include <stdint.h>
# include <stdlib.h>
# include <list.h>
# include <kernel-features.h>
# include <dl-dtv.h>

typedef struct
{
  void *tcb;		/* Pointer to the TCB.  Not necessary the
			   thread descriptor used by libpthread.  */
  dtv_t *dtv;
  void *self;		/* Pointer to the thread descriptor.  */
  int multiple_threads;
  uintptr_t sysinfo;
  uintptr_t stack_guard;
  int gscope_flag;
  int __glibc_reserved1;
  /* GCC split stack support.  */
  void *__private_ss;
} tcbhead_t;

# ifndef __s390x__
#  define TLS_MULTIPLE_THREADS_IN_TCB 1
# endif

#else /* __ASSEMBLER__ */
# include <tcb-offsets.h>
#endif


/* Alignment requirement for the stack.  For IA-32 this is governed by
   the SSE memory functions.  */
#define STACK_ALIGN	16

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

/* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
   because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
   struct pthread even when not linked with -lpthread.  */
# define TLS_INIT_TCB_SIZE sizeof (struct pthread)

/* This is the size of the TCB.  */
# define TLS_TCB_SIZE sizeof (struct pthread)

/* The TCB can have any size and the memory following the address the
   thread pointer points to is unspecified.  Allocate the TCB there.  */
# define TLS_TCB_AT_TP	1
# define TLS_DTV_AT_TP	0

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


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

/* Install new dtv for current thread.  */
#  define INSTALL_NEW_DTV(dtv) \
  (((tcbhead_t *) __builtin_thread_pointer ())->dtv = (dtv))

/* Return dtv of given thread descriptor.  */
#  define GET_DTV(descr) \
  (((tcbhead_t *) (descr))->dtv)

#if defined NEED_DL_SYSINFO && defined SHARED
# define INIT_SYSINFO \
  _head->sysinfo = GLRO(dl_sysinfo)
#else
# define INIT_SYSINFO
#endif

/* Code to initially initialize the thread pointer.  This might need
   special attention since 'errno' is not yet available and if the
   operation can cause a failure 'errno' must not be touched.  */
# define TLS_INIT_TP(thrdescr) \
  ({ void *_thrdescr = (thrdescr);					      \
     tcbhead_t *_head = _thrdescr;					      \
									      \
     _head->tcb = _thrdescr;						      \
     /* For now the thread descriptor is at the same address.  */	      \
     _head->self = _thrdescr;						      \
     /* New syscall handling support.  */				      \
     INIT_SYSINFO;							      \
									      \
    __builtin_set_thread_pointer (_thrdescr);				      \
    true;								      \
  })

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

/* Return the address of the dtv for the current thread.  */
#  define THREAD_DTV() \
  (((tcbhead_t *) __builtin_thread_pointer ())->dtv)

/* Return the thread descriptor for the current thread.  */
# define THREAD_SELF ((struct pthread *) __builtin_thread_pointer ())

/* Magic for libthread_db to know how to do THREAD_SELF.  */
# define DB_THREAD_SELF REGISTER (32, 32, 18 * 4, 0) \
			REGISTER (64, __WORDSIZE, 18 * 8, 0)

# include <tcb-access.h>

/* Set the stack guard field in TCB head.  */
#define THREAD_SET_STACK_GUARD(value) \
  do									      \
   {									      \
     __asm__ __volatile__ ("" : : : "a0", "a1");			      \
     THREAD_SETMEM (THREAD_SELF, header.stack_guard, value);		      \
   }									      \
  while (0)
#define THREAD_COPY_STACK_GUARD(descr) \
  ((descr)->header.stack_guard						      \
   = THREAD_GETMEM (THREAD_SELF, header.stack_guard))

/* s390 doesn't have HP_TIMING_*, so for the time being
   use stack_guard as pointer_guard.  */
#define THREAD_GET_POINTER_GUARD() \
  THREAD_GETMEM (THREAD_SELF, header.stack_guard)
#define THREAD_SET_POINTER_GUARD(value)	((void) (value))
#define THREAD_COPY_POINTER_GUARD(descr)

/* Get and set the global scope generation counter in struct pthread.  */
#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 */