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(n: vdso_pages + 1, size: 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, addr: vdso_base, len: vdso_pages << PAGE_SHIFT, |
70 | flags: (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC), |
71 | pages: 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, addr: vdso_base, PAGE_SIZE, |
80 | flags: (VM_READ | VM_MAYREAD), pages: &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 | |