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/* Definitions for thread-local data handling. linuxthreads/PPC version.
Copyright (C) 2003 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _TLS_H
#define _TLS_H
#ifndef __ASSEMBLER__
# include <pt-machine.h>
# include <stddef.h>
/* Type for the dtv. */
typedef union dtv
{
size_t counter;
void *pointer;
} dtv_t;
#endif /* __ASSEMBLER__ */
#ifdef HAVE_TLS_SUPPORT
/* Signal that TLS support is available. */
# define USE_TLS 1
# ifndef __ASSEMBLER__
/* This layout is actually wholly private and not affected by the ABI.
Nor does it overlap the pthread data structure, so we need nothing
extra here at all. */
typedef struct
{
dtv_t *dtv;
} tcbhead_t;
/* This is the size of the initial TCB. */
# define TLS_INIT_TCB_SIZE 0
/* Alignment requirements for the initial TCB. */
# define TLS_INIT_TCB_ALIGN __alignof__ (struct _pthread_descr_struct)
/* This is the size of the TCB. */
# define TLS_TCB_SIZE 0
/* Alignment requirements for the TCB. */
# define TLS_TCB_ALIGN __alignof__ (struct _pthread_descr_struct)
/* This is the size we need before TCB. */
# define TLS_PRE_TCB_SIZE \
(sizeof (struct _pthread_descr_struct) \
+ ((sizeof (tcbhead_t) + TLS_TCB_ALIGN - 1) & ~(TLS_TCB_ALIGN - 1)))
/* The following assumes that TP (R2 or R13) is points to the end of the
TCB + 0x7000 (per the ABI). This implies that TCB address is
TP - 0x7000. As we define TLS_DTV_AT_TP we can
assume that the pthread_descr is allocated immediately ahead of the
TCB. This implies that the pthread_descr address is
TP - (TLS_PRE_TCB_SIZE + 0x7000). */
#define TLS_TCB_OFFSET 0x7000
/* The DTV is allocated at the TP; the TCB is placed elsewhere. */
/* This is not really true for powerpc64. We are following alpha
where the DTV pointer is first doubleword in the TCB. */
# define TLS_DTV_AT_TP 1
/* 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)
/* The global register variable is declared in pt-machine.h with
the wrong type, but the compiler doesn't like us declaring another. */
# define __thread_register ((void *) __thread_self)
/* 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, SECONDCALL) \
(__thread_register = (void *) (TCBP) + TLS_TCB_OFFSET, NULL)
/* Return the address of the dtv for the current thread. */
# define THREAD_DTV() \
(((tcbhead_t *) (__thread_register - TLS_TCB_OFFSET))[-1].dtv)
/* Return the thread descriptor for the current thread. */
# undef THREAD_SELF
# define THREAD_SELF \
((pthread_descr) (__thread_register \
- TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
# undef INIT_THREAD_SELF
# define INIT_THREAD_SELF(DESCR, NR) \
(__thread_register = ((void *) (DESCR) \
+ TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE))
/* Make sure we have the p_multiple_threads member in the thread structure.
See below. */
# ifndef __powerpc64__
# define TLS_MULTIPLE_THREADS_IN_TCB 1
# endif
/* Get the thread descriptor definition. */
# include <linuxthreads/descr.h>
/* l_tls_offset == 0 is perfectly valid on PPC, so we have to use some
different value to mean unset l_tls_offset. */
# define NO_TLS_OFFSET -1
# endif /* __ASSEMBLER__ */
#elif !defined __ASSEMBLER__ && !defined __powerpc64__
/* This overlaps the start of the pthread_descr. On PPC32, system
calls and such use this to find the multiple_threads flag and need
to use the same offset relative to the thread register in both
single-threaded and multi-threaded code. On PPC64, the global
variable is always used, so single-threaded code without TLS
never needs to initialize the thread register at all. */
typedef struct
{
void *tcb; /* Never used. */
dtv_t *dtv; /* Never used. */
void *self; /* Used only if multithreaded, and rarely. */
int multiple_threads; /* Only this member is really used. */
} tcbhead_t;
#define NONTLS_INIT_TP \
do { \
static const tcbhead_t nontls_init_tp = { .multiple_threads = 0 }; \
__thread_self = (__typeof (__thread_self)) &nontls_init_tp; \
} while (0)
#endif /* HAVE_TLS_SUPPORT */
#endif /* tls.h */
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