1 /* Definition for thread-local data handling.
2    Copyright (C) 2022 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 _LOONGARCH_TLS_H
20 #define _LOONGARCH_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 /* Alignment requirements for the initial TCB.  */
54 #define TLS_INIT_TCB_ALIGN __alignof__(struct pthread)
55 
56 /* This is the size of the TCB.  Because our TCB is before the thread
57    pointer, we don't need this.  */
58 #define TLS_TCB_SIZE 0
59 
60 /* Alignment requirements for the TCB.  */
61 #define TLS_TCB_ALIGN __alignof__(struct pthread)
62 
63 /* This is the size we need before TCB - actually, it includes the TCB.  */
64 #define TLS_PRE_TCB_SIZE \
65   (sizeof (struct pthread) \
66    + ((sizeof (tcbhead_t) + TLS_TCB_ALIGN - 1) & ~(TLS_TCB_ALIGN - 1)))
67 
68 /* The thread pointer tp points to the end of the TCB.
69    The pthread_descr structure is immediately in front of the TCB.  */
70 #define TLS_TCB_OFFSET 0
71 
72 /* Install the dtv pointer.  The pointer passed is to the element with
73    index -1 which contain the length.  */
74 #define INSTALL_DTV(tcbp, dtvp) (((tcbhead_t *) (tcbp))[-1].dtv = (dtvp) + 1)
75 
76 /* Install new dtv for current thread.  */
77 #define INSTALL_NEW_DTV(dtv) (THREAD_DTV () = (dtv))
78 
79 /* Return dtv of given thread descriptor.  */
80 #define GET_DTV(tcbp) (((tcbhead_t *) (tcbp))[-1].dtv)
81 
82 /* Code to initially initialize the thread pointer.  */
83 #define TLS_INIT_TP(tcbp) \
84   ({ \
85     __thread_self = (char *) tcbp + TLS_TCB_OFFSET; \
86     NULL; \
87   })
88 
89 /* Return the address of the dtv for the current thread.  */
90 #define THREAD_DTV() \
91   (((tcbhead_t *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET))[-1].dtv)
92 
93 /* Return the thread descriptor for the current thread.  */
94 #define THREAD_SELF \
95   ((struct pthread *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET \
96 		       - TLS_PRE_TCB_SIZE))
97 
98 /* Value passed to 'clone' for initialization of the thread register.  */
99 #define TLS_DEFINE_INIT_TP(tp, pd) \
100   void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE
101 
102 /* Informs libthread_db that the thread pointer is register 2, which is used
103  * to know how to do THREAD_SELF.  */
104 #define DB_THREAD_SELF \
105   REGISTER (64, 64, 2 * 8, -TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE)
106 
107 /* Access to data in the thread descriptor is easy.  */
108 # include <tcb-access.h>
109 
110 /* l_tls_offset == 0 is perfectly valid, so we have to use some different
111    value to mean unset l_tls_offset.  */
112 #define NO_TLS_OFFSET -1
113 
114 /* Get and set the global scope generation counter in struct pthread.  */
115 #define THREAD_GSCOPE_IN_TCB 1
116 #define THREAD_GSCOPE_FLAG_UNUSED 0
117 #define THREAD_GSCOPE_FLAG_USED 1
118 #define THREAD_GSCOPE_FLAG_WAIT 2
119 #define THREAD_GSCOPE_RESET_FLAG() \
120   do \
121     { \
122       int __res = atomic_exchange_rel (&THREAD_SELF->header.gscope_flag, \
123 				       THREAD_GSCOPE_FLAG_UNUSED); \
124       if (__res == THREAD_GSCOPE_FLAG_WAIT) \
125 	lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); \
126     } \
127   while (0)
128 #define THREAD_GSCOPE_SET_FLAG() \
129   do \
130     { \
131       THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED; \
132       atomic_write_barrier (); \
133     } \
134   while (0)
135 
136 #endif /* __ASSEMBLER__ */
137 
138 #endif /* tls.h */
139