glibc/sysdeps/mips/nptl/tls.h

/* Definition for thread-local data handling.  NPTL/MIPS version.
   Copyright (C) 2005-2024 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 <dl-dtv.h>

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

#ifdef __mips16
/* MIPS16 uses GCC builtin to access the TP.  */
# define READ_THREAD_POINTER() (__builtin_thread_pointer ())
#else
/* Note: rd must be $v1 to be ABI-conformant.  */
# if defined (__mips_isa_rev) &&  __mips_isa_rev >= 2
#  define READ_THREAD_POINTER() \
     ({ void *__result;							      \
        asm volatile ("rdhwr\t%0, $29" : "=v" (__result));	      	      \
        __result; })
# else
#  define READ_THREAD_POINTER() \
     ({ void *__result;							      \
        asm volatile (".set\tpush\n\t.set\tmips32r2\n\t"			      \
		      "rdhwr\t%0, $29\n\t.set\tpop" : "=v" (__result));	      \
        __result; })
# endif
#endif

#else /* __ASSEMBLER__ */
# if __mips_isa_rev >= 2
#  define READ_THREAD_POINTER(rd) rdhwr	rd, $29
# else
#  define READ_THREAD_POINTER(rd) \
	 .set	push;							      \
	 .set	mips32r2;						      \
	 rdhwr	rd, $29;						      \
	 .set	pop
# endif
#endif /* __ASSEMBLER__ */


#ifndef __ASSEMBLER__

/* 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

/* 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

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

/* The thread pointer (in hardware register $29) points to the end of
   the TCB + 0x7000, as for PowerPC.  The pthread_descr structure is
   immediately in front of the TCB.  */
# define TLS_TCB_OFFSET	0x7000

/* 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.  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(tcbp) \
  ({ long int result_var;						\
     result_var = INTERNAL_SYSCALL_CALL (set_thread_area, 		\
				    (char *) (tcbp) + TLS_TCB_OFFSET);	\
     !INTERNAL_SYSCALL_ERROR_P (result_var); })

/* 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

/* 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))

/* Magic for libthread_db to know how to do THREAD_SELF.  */
# define DB_THREAD_SELF \
  CONST_THREAD_AREA (32, 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 on MIPS, 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_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 */