1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
3
4 #include <linux/binfmts.h>
5 #include <linux/elf.h>
6 #include <linux/err.h>
7 #include <linux/mm.h>
8 #include <linux/slab.h>
9
10 #include <asm/page.h>
11 #include <vdso/datapage.h>
12
13 extern char vdso_start[], vdso_end[];
14
15 static unsigned int vdso_pages;
16 static struct page **vdso_pagelist;
17
18 static union vdso_data_store vdso_data_store __page_aligned_data;
19 struct vdso_data *vdso_data = vdso_data_store.data;
20
21 static int __init vdso_init(void)
22 {
23 unsigned int i;
24
25 vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
26 vdso_pagelist =
27 kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
28 if (unlikely(vdso_pagelist == NULL)) {
29 pr_err("vdso: pagelist allocation failed\n");
30 return -ENOMEM;
31 }
32
33 for (i = 0; i < vdso_pages; i++) {
34 struct page *pg;
35
36 pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
37 vdso_pagelist[i] = pg;
38 }
39 vdso_pagelist[i] = virt_to_page(vdso_data);
40
41 return 0;
42 }
43 arch_initcall(vdso_init);
44
45 int arch_setup_additional_pages(struct linux_binprm *bprm,
46 int uses_interp)
47 {
48 struct mm_struct *mm = current->mm;
49 unsigned long vdso_base, vdso_len;
50 int ret;
51
52 vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
53
54 mmap_write_lock(mm);
55 vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
56 if (IS_ERR_VALUE(vdso_base)) {
57 ret = vdso_base;
58 goto end;
59 }
60
61 /*
62 * Put vDSO base into mm struct. We need to do this before calling
63 * install_special_mapping or the perf counter mmap tracking code
64 * will fail to recognise it as a vDSO (since arch_vma_name fails).
65 */
66 mm->context.vdso = (void *)vdso_base;
67
68 ret =
69 install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
70 (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
71 vdso_pagelist);
72
73 if (unlikely(ret)) {
74 mm->context.vdso = NULL;
75 goto end;
76 }
77
78 vdso_base += (vdso_pages << PAGE_SHIFT);
79 ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
80 (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);
81
82 if (unlikely(ret))
83 mm->context.vdso = NULL;
84 end:
85 mmap_write_unlock(mm);
86 return ret;
87 }
88
89 const char *arch_vma_name(struct vm_area_struct *vma)
90 {
91 if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
92 return "[vdso]";
93 if (vma->vm_mm && (vma->vm_start ==
94 (long)vma->vm_mm->context.vdso + PAGE_SIZE))
95 return "[vdso_data]";
96 return NULL;
97 }
98
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