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
|
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <asm/page.h>
#include <vdso/datapage.h>
extern char vdso_start[], vdso_end[];
static unsigned int vdso_pages;
static struct page **vdso_pagelist;
static union vdso_data_store vdso_data_store __page_aligned_data;
struct vdso_data *vdso_data = vdso_data_store.data;
static int __init vdso_init(void)
{
unsigned int i;
vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
vdso_pagelist =
kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
if (unlikely(vdso_pagelist == NULL)) {
pr_err("vdso: pagelist allocation failed\n");
return -ENOMEM;
}
for (i = 0; i < vdso_pages; i++) {
struct page *pg;
pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
vdso_pagelist[i] = pg;
}
vdso_pagelist[i] = virt_to_page(vdso_data);
return 0;
}
arch_initcall(vdso_init);
int arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long vdso_base, vdso_len;
int ret;
static struct vm_special_mapping vdso_mapping = {
.name = "[vdso]",
};
static struct vm_special_mapping vvar_mapping = {
.name = "[vvar]",
};
vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
mmap_write_lock(mm);
vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
if (IS_ERR_VALUE(vdso_base)) {
ret = vdso_base;
goto end;
}
/*
* Put vDSO base into mm struct. We need to do this before calling
* install_special_mapping or the perf counter mmap tracking code
* will fail to recognise it as a vDSO (since arch_vma_name fails).
*/
mm->context.vdso = (void *)vdso_base;
vdso_mapping.pages = vdso_pagelist;
vma =
_install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
(VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
&vdso_mapping);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
mm->context.vdso = NULL;
goto end;
}
vdso_base += (vdso_pages << PAGE_SHIFT);
vvar_mapping.pages = &vdso_pagelist[vdso_pages];
vma = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
(VM_READ | VM_MAYREAD), &vvar_mapping);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
mm->context.vdso = NULL;
goto end;
}
ret = 0;
end:
mmap_write_unlock(mm);
return ret;
}
const char *arch_vma_name(struct vm_area_struct *vma)
{
if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
return "[vdso]";
if (vma->vm_mm && (vma->vm_start ==
(long)vma->vm_mm->context.vdso + PAGE_SIZE))
return "[vdso_data]";
return NULL;
}
|
