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1/* Definition for thread-local data handling. NPTL/m68k version.
2 Copyright (C) 2010-2024 Free Software Foundation, Inc.
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
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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
43typedef struct
44{
45 dtv_t *dtv;
46 void *private;
47} tcbhead_t;
48
49/* This is the size of the initial TCB. Because our TCB is before the thread
50 pointer, we don't need this. */
51# define TLS_INIT_TCB_SIZE 0
52
53/* This is the size of the TCB. Because our TCB is before the thread
54 pointer, we don't need this. */
55# define TLS_TCB_SIZE 0
56
57/* This is the size we need before TCB - actually, it includes the TCB. */
58# define TLS_PRE_TCB_SIZE \
59 (sizeof (struct pthread) \
60 + ((sizeof (tcbhead_t) + __alignof (struct pthread) - 1) \
61 & ~(__alignof (struct pthread) - 1)))
62
63/* The thread pointer (TP) points to the end of the
64 TCB + 0x7000, as for PowerPC and MIPS. This implies that TCB address is
65 TP - 0x7000. As we define TLS_DTV_AT_TP we can
66 assume that the pthread struct is allocated immediately ahead of the
67 TCB. This implies that the pthread_descr address is
68 TP - (TLS_PRE_TCB_SIZE + 0x7000). */
69# define TLS_TCB_OFFSET 0x7000
70
71/* Install the dtv pointer. The pointer passed is to the element with
72 index -1 which contain the length. */
73# define INSTALL_DTV(tcbp, dtvp) \
74 ((tcbhead_t *) (tcbp))[-1].dtv = dtvp + 1
75
76/* Install new dtv for current thread. */
77# define INSTALL_NEW_DTV(dtv) \
78 (THREAD_DTV () = (dtv))
79
80/* Return dtv of given thread descriptor. */
81# define GET_DTV(tcbp) \
82 (((tcbhead_t *) (tcbp))[-1].dtv)
83
84/* Code to initially initialize the thread pointer. This might need
85 special attention since 'errno' is not yet available and if the
86 operation can cause a failure 'errno' must not be touched. */
87# define TLS_INIT_TP(tcbp) \
88 ({ \
89 int _sys_result; \
90 \
91 _sys_result = INTERNAL_SYSCALL_CALL (set_thread_area, \
92 ((void *) (tcbp)) + TLS_TCB_OFFSET); \
93 !INTERNAL_SYSCALL_ERROR_P (_sys_result); })
94
95# define TLS_DEFINE_INIT_TP(tp, pd) \
96 void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE
97
98extern void * __m68k_read_tp (void);
99
100/* Return the address of the dtv for the current thread. */
101# define THREAD_DTV() \
102 (((tcbhead_t *) (__m68k_read_tp () - TLS_TCB_OFFSET))[-1].dtv)
103
104/* Return the thread descriptor for the current thread. */
105# define THREAD_SELF \
106 ((struct pthread *) (__m68k_read_tp () - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
107
108/* Magic for libthread_db to know how to do THREAD_SELF. */
109# define DB_THREAD_SELF \
110 CONST_THREAD_AREA (32, TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE)
111
112# include <tcb-access.h>
113
114/* l_tls_offset == 0 is perfectly valid on M68K, so we have to use some
115 different value to mean unset l_tls_offset. */
116# define NO_TLS_OFFSET -1
117
118/* Get and set the global scope generation counter in struct pthread. */
119#define THREAD_GSCOPE_FLAG_UNUSED 0
120#define THREAD_GSCOPE_FLAG_USED 1
121#define THREAD_GSCOPE_FLAG_WAIT 2
122#define THREAD_GSCOPE_RESET_FLAG() \
123 do \
124 { int __res \
125 = atomic_exchange_release (&THREAD_SELF->header.gscope_flag, \
126 THREAD_GSCOPE_FLAG_UNUSED); \
127 if (__res == THREAD_GSCOPE_FLAG_WAIT) \
128 lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); \
129 } \
130 while (0)
131#define THREAD_GSCOPE_SET_FLAG() \
132 do \
133 { \
134 THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED; \
135 atomic_write_barrier (); \
136 } \
137 while (0)
138
139#endif /* __ASSEMBLER__ */
140
141#endif /* tls.h */
142

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source code of glibc/sysdeps/m68k/nptl/tls.h