1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/* Initialization code for TLS in statically linked application.
Copyright (C) 2002 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. */
#include <errno.h>
#include <ldsodefs.h>
#include <tls.h>
#include <unistd.h>
#ifdef SHARED
#error makefile bug, this file is for static only
#endif
#ifdef USE_TLS
extern ElfW(Phdr) *_dl_phdr;
extern size_t _dl_phnum;
/* DTV with just one element plus overhead. */
static dtv_t static_dtv[3];
static struct
{
struct dtv_slotinfo_list si;
/* The dtv_slotinfo_list data structure does not include the actual
information since it is defined as an array of size zero. We define
here the necessary entries. Note that it is not important whether
there is padding or not since we will always access the information
through the 'si' element. */
struct dtv_slotinfo info[2 + TLS_SLOTINFO_SURPLUS];
} static_slotinfo;
/* Fake link map for the application. */
static struct link_map static_map;
/* Highest dtv index currently needed. */
size_t _dl_tls_max_dtv_idx;
/* Flag signalling whether there are gaps in the module ID allocation. */
bool _dl_tls_dtv_gaps;
/* Information about the dtv slots. */
struct dtv_slotinfo_list *_dl_tls_dtv_slotinfo_list;
/* Number of modules in the static TLS block. */
size_t _dl_tls_static_nelem;
/* Size of the static TLS block. */
size_t _dl_tls_static_size;
/* Alignment requirement of the static TLS block. */
size_t _dl_tls_static_align;
/* Generation counter for the dtv. */
size_t _dl_tls_generation;
/* Additional definitions needed by TLS initialization. */
#ifdef TLS_INIT_HELPER
TLS_INIT_HELPER
#endif
void
__libc_setup_tls (size_t tcbsize, size_t tcbalign)
{
void *tlsblock;
size_t memsz = 0;
size_t filesz = 0;
void *initimage = NULL;
size_t align = 0;
size_t max_align = tcbalign;
size_t tcb_offset;
ElfW(Phdr) *phdr;
/* Look through the TLS segment if there is any. */
if (_dl_phdr != NULL)
for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)
if (phdr->p_type == PT_TLS)
{
/* Remember the values we need. */
memsz = phdr->p_memsz;
filesz = phdr->p_filesz;
initimage = (void *) phdr->p_vaddr;
align = phdr->p_align;
if (phdr->p_align > max_align)
max_align = phdr->p_align;
break;
}
if (memsz == 0 && tcbsize == 0)
/* We do not need a TLS block and no thread descriptor. */
return;
/* We have to set up the TCB block which also (possibly) contains
'errno'. Therefore we avoid 'malloc' which might touch 'errno'.
Instead we use 'sbrk' which would only uses 'errno' if it fails.
In this case we are right away out of memory and the user gets
what she/he deserves. */
# if TLS_TCB_AT_TP
tlsblock = __sbrk (roundup (memsz, tcbalign) + tcbsize + max_align);
# elif TLS_DTV_AT_TP
tlsblock = __sbrk (roundup (tcbsize, align) + memsz + max_align);
# else
/* In case a model with a different layout for the TCB and DTV
is defined add another #elif here and in the following #ifs. */
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif
/* Align the TLS block. */
tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
& ~(max_align - 1));
/* Initialize the dtv. [0] is the length, [1] the generation counter. */
static_dtv[0].counter = 1;
// static_dtv[1].counter = 0; would be needed if not already done
/* Initialize the TLS block. */
# if TLS_TCB_AT_TP
static_dtv[2].pointer = tlsblock;
# elif TLS_DTV_AT_TP
tcb_offset = roundup (tcbsize, align);
static_dtv[2].pointer = (char *) tlsblock + tcb_offset;
# else
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif
memset (__mempcpy (static_dtv[2].pointer, initimage, filesz),
'\0', memsz - filesz);
/* Install the pointer to the dtv. */
/* Initialize the thread pointer. */
# if TLS_TCB_AT_TP
tcb_offset = roundup (memsz, tcbalign);
INSTALL_DTV ((char *) tlsblock + tcb_offset, static_dtv);
TLS_INIT_TP ((char *) tlsblock + tcb_offset, 0);
# elif TLS_DTV_AT_TP
INSTALL_DTV (tlsblock, static_dtv);
TLS_INIT_TP (tlsblock, 0);
# else
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif
/* We have to create a fake link map which normally would be created
by the dynamic linker. It just has to have enough information to
make the TLS routines happy. */
static_map.l_tls_align = align;
static_map.l_tls_blocksize = memsz;
static_map.l_tls_initimage = initimage;
static_map.l_tls_initimage_size = filesz;
static_map.l_tls_offset = tcb_offset;
static_map.l_type = lt_executable;
static_map.l_tls_modid = 1;
/* Create the slotinfo list. */
static_slotinfo.si.len = (((char *) (&static_slotinfo + 1)
- (char *) &static_slotinfo.si.slotinfo[0])
/ sizeof static_slotinfo.si.slotinfo[0]);
// static_slotinfo.si.next = NULL; already zero
static_slotinfo.si.slotinfo[1].gen = 0;
static_slotinfo.si.slotinfo[1].map = &static_map;
/* The slotinfo list. Will be extended by the code doing dynamic
linking. */
GL(dl_tls_max_dtv_idx) = 1;
GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo.si;
/* That is the size of the TLS memory for this object. */
GL(dl_tls_static_size) = (roundup (memsz, align ?: 1)
# if TLS_TCB_AT_TP
+ tcbsize
# endif
);
/* The alignment requirement for the static TLS block. */
GL(dl_tls_static_align) = MAX (TLS_TCB_ALIGN, max_align);
/* Number of elements in the static TLS block. */
GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
}
/* This is the minimal initialization function used when libpthread is
not used. */
void
__attribute__ ((weak))
__pthread_initialize_minimal (void)
{
__libc_setup_tls (TLS_INIT_TCB_SIZE, TLS_INIT_TCB_ALIGN);
}
#endif
|
