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
|
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "runtime.h"
#include "arch_GOARCH.h"
#include "defs_GOOS_GOARCH.h"
#include "os_GOOS.h"
#include "malloc.h"
enum
{
_PAGE_SIZE = 4096,
};
static int32
addrspace_free(void *v, uintptr n)
{
int32 errval;
uintptr chunk;
uintptr off;
static byte vec[4096];
for(off = 0; off < n; off += chunk) {
chunk = _PAGE_SIZE * sizeof vec;
if(chunk > (n - off))
chunk = n - off;
errval = runtime·mincore((int8*)v + off, chunk, vec);
// errval is 0 if success, or -(error_code) if error.
if (errval == 0 || errval != -ENOMEM)
return 0;
}
return 1;
}
static void *
mmap_fixed(byte *v, uintptr n, int32 prot, int32 flags, int32 fd, uint32 offset)
{
void *p;
p = runtime·mmap(v, n, prot, flags, fd, offset);
if(p != v && addrspace_free(v, n)) {
// On some systems, mmap ignores v without
// MAP_FIXED, so retry if the address space is free.
if(p > (void*)4096)
runtime·munmap(p, n);
p = runtime·mmap(v, n, prot, flags|MAP_FIXED, fd, offset);
}
return p;
}
void*
runtime·SysAlloc(uintptr n, uint64 *stat)
{
void *p;
p = runtime·mmap(nil, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p < (void*)4096) {
if(p == (void*)EACCES) {
runtime·printf("runtime: mmap: access denied\n");
runtime·printf("if you're running SELinux, enable execmem for this process.\n");
runtime·exit(2);
}
if(p == (void*)EAGAIN) {
runtime·printf("runtime: mmap: too much locked memory (check 'ulimit -l').\n");
runtime·exit(2);
}
return nil;
}
runtime·xadd64(stat, n);
return p;
}
void
runtime·SysUnused(void *v, uintptr n)
{
runtime·madvise(v, n, MADV_DONTNEED);
}
void
runtime·SysUsed(void *v, uintptr n)
{
USED(v);
USED(n);
}
void
runtime·SysFree(void *v, uintptr n, uint64 *stat)
{
runtime·xadd64(stat, -(uint64)n);
runtime·munmap(v, n);
}
void*
runtime·SysReserve(void *v, uintptr n)
{
void *p;
// On 64-bit, people with ulimit -v set complain if we reserve too
// much address space. Instead, assume that the reservation is okay
// if we can reserve at least 64K and check the assumption in SysMap.
// Only user-mode Linux (UML) rejects these requests.
if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) {
p = mmap_fixed(v, 64<<10, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
if (p != v) {
if(p >= (void*)4096)
runtime·munmap(p, 64<<10);
return nil;
}
runtime·munmap(p, 64<<10);
return v;
}
p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
if((uintptr)p < 4096)
return nil;
return p;
}
void
runtime·SysMap(void *v, uintptr n, uint64 *stat)
{
void *p;
runtime·xadd64(stat, n);
// On 64-bit, we don't actually have v reserved, so tread carefully.
if(sizeof(void*) == 8 && (uintptr)v >= 0xffffffffU) {
p = mmap_fixed(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p == (void*)ENOMEM)
runtime·throw("runtime: out of memory");
if(p != v) {
runtime·printf("runtime: address space conflict: map(%p) = %p\n", v, p);
runtime·throw("runtime: address space conflict");
}
return;
}
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
if(p == (void*)ENOMEM)
runtime·throw("runtime: out of memory");
if(p != v)
runtime·throw("runtime: cannot map pages in arena address space");
}
|
