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
|
#include <elf.h>
#include <limits.h>
#include <sys/mman.h>
#include <string.h>
#include "pthread_impl.h"
#include "libc.h"
#include "atomic.h"
#include "syscall.h"
int __init_tp(void *p)
{
pthread_t td = p;
td->self = td;
if (__set_thread_area(TP_ADJ(p)) < 0)
return -1;
td->tid = td->pid = __syscall(SYS_set_tid_address, &td->tid);
td->errno_ptr = &td->errno_val;
/* Currently, both of these predicates depend in the same thing:
* successful initialization of the thread pointer. However, in
* the future, we may support setups where setting the thread
* pointer is possible but threads other than the main thread
* cannot work, so it's best to keep the predicates separate. */
libc.has_thread_pointer = 1;
libc.can_do_threads = 1;
return 0;
}
#ifndef SHARED
static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
struct tls_image {
void *image;
size_t len, size, align;
} __static_tls ATTR_LIBC_VISIBILITY;
#define T __static_tls
void *__copy_tls(unsigned char *mem)
{
pthread_t td;
if (!T.image) return mem;
void **dtv = (void *)mem;
dtv[0] = (void *)1;
#ifdef TLS_ABOVE_TP
mem += sizeof(void *) * 2;
mem += -((uintptr_t)mem + sizeof(struct pthread)) & (T.align-1);
td = (pthread_t)mem;
mem += sizeof(struct pthread);
#else
mem += libc.tls_size - sizeof(struct pthread);
mem -= (uintptr_t)mem & (T.align-1);
td = (pthread_t)mem;
mem -= T.size;
#endif
td->dtv = dtv;
dtv[1] = mem;
memcpy(mem, T.image, T.len);
return td;
}
void *__tls_get_addr(size_t *v)
{
return (char *)__pthread_self()->dtv[1]+v[1];
}
void *__mmap(void *, size_t, int, int, int, off_t);
#if ULONG_MAX == 0xffffffff
typedef Elf32_Phdr Phdr;
#else
typedef Elf64_Phdr Phdr;
#endif
void __init_tls(size_t *aux)
{
unsigned char *p;
size_t n;
Phdr *phdr, *tls_phdr=0;
size_t base = 0;
void *mem;
libc.tls_size = sizeof(struct pthread);
for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
phdr = (void *)p;
if (phdr->p_type == PT_PHDR)
base = aux[AT_PHDR] - phdr->p_vaddr;
if (phdr->p_type == PT_TLS)
tls_phdr = phdr;
}
if (tls_phdr) {
T.image = (void *)(base + tls_phdr->p_vaddr);
T.len = tls_phdr->p_filesz;
T.size = tls_phdr->p_memsz;
T.align = tls_phdr->p_align;
}
T.size += (-T.size - (uintptr_t)T.image) & (T.align-1);
if (T.align < 4*sizeof(size_t)) T.align = 4*sizeof(size_t);
libc.tls_size = 2*sizeof(void *)+T.size+T.align+sizeof(struct pthread);
if (libc.tls_size > sizeof builtin_tls) {
mem = (void *)__syscall(
#ifdef SYS_mmap2
SYS_mmap2,
#else
SYS_mmap,
#endif
0, libc.tls_size, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
/* -4095...-1 cast to void * will crash on dereference anyway,
* so don't bloat the init code checking for error codes and
* explicitly calling a_crash(). */
} else {
mem = builtin_tls;
}
/* Failure to initialize thread pointer is fatal if TLS is used. */
if (__init_tp(__copy_tls(mem)) < 0 && tls_phdr)
a_crash();
}
#else
void __init_tls(size_t *auxv) { }
#endif
|
