1 /* Definition for thread-local data handling. NPTL/RISC-V version.
2 Copyright (C) 2011-2023 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 _RISCV_TLS_H
20 #define _RISCV_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
30 register void *__thread_self asm ("tp");
31 # define READ_THREAD_POINTER() ({ __thread_self; })
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
43 typedef 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 TCB.
64 The pthread_descr structure is immediately in front of the TCB. */
65 # define TLS_TCB_OFFSET 0
66
67 /* Install the dtv pointer. The pointer passed is to the element with
68 index -1 which contain the length. */
69 # define INSTALL_DTV(tcbp, dtvp) \
70 (((tcbhead_t *) (tcbp))[-1].dtv = (dtvp) + 1)
71
72 /* Install new dtv for current thread. */
73 # define INSTALL_NEW_DTV(dtv) \
74 (THREAD_DTV() = (dtv))
75
76 /* Return dtv of given thread descriptor. */
77 # define GET_DTV(tcbp) \
78 (((tcbhead_t *) (tcbp))[-1].dtv)
79
80 /* Code to initially initialize the thread pointer. */
81 # define TLS_INIT_TP(tcbp) \
82 ({ __thread_self = (char*)tcbp + TLS_TCB_OFFSET; true; })
83
84 /* Return the address of the dtv for the current thread. */
85 # define THREAD_DTV() \
86 (((tcbhead_t *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET))[-1].dtv)
87
88 /* Return the thread descriptor for the current thread. */
89 # define THREAD_SELF \
90 ((struct pthread *) (READ_THREAD_POINTER () \
91 - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
92
93 /* Value passed to 'clone' for initialization of the thread register. */
94 # define TLS_DEFINE_INIT_TP(tp, pd) \
95 void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE
96
97 /* Informs libthread_db that the thread pointer is register 4, which is used
98 * to know how to do THREAD_SELF. */
99 # define DB_THREAD_SELF \
100 REGISTER (64, 64, 4 * 8, - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE)
101
102 /* Access to data in the thread descriptor is easy. */
103 # include <tcb-access.h>
104
105 /* l_tls_offset == 0 is perfectly valid, so we have to use some different
106 value to mean unset l_tls_offset. */
107 # define NO_TLS_OFFSET -1
108
109 /* Get and set the global scope generation counter in struct pthread. */
110 # define THREAD_GSCOPE_FLAG_UNUSED 0
111 # define THREAD_GSCOPE_FLAG_USED 1
112 # define THREAD_GSCOPE_FLAG_WAIT 2
113 # define THREAD_GSCOPE_RESET_FLAG() \
114 do \
115 { int __res \
116 = atomic_exchange_release (&THREAD_SELF->header.gscope_flag, \
117 THREAD_GSCOPE_FLAG_UNUSED); \
118 if (__res == THREAD_GSCOPE_FLAG_WAIT) \
119 lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); \
120 } \
121 while (0)
122 # define THREAD_GSCOPE_SET_FLAG() \
123 do \
124 { \
125 THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED; \
126 atomic_write_barrier (); \
127 } \
128 while (0)
129
130 #endif /* __ASSEMBLER__ */
131
132 #endif /* tls.h */