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caab277b | 1 | // SPDX-License-Identifier: GPL-2.0-only |
76d2a049 PD |
2 | /* |
3 | * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp. | |
4 | * <benh@kernel.crashing.org> | |
5 | * Copyright (C) 2012 ARM Limited | |
6 | * Copyright (C) 2015 Regents of the University of California | |
76d2a049 PD |
7 | */ |
8 | ||
5ed881bc | 9 | #include <linux/elf.h> |
76d2a049 PD |
10 | #include <linux/mm.h> |
11 | #include <linux/slab.h> | |
12 | #include <linux/binfmts.h> | |
13 | #include <linux/err.h> | |
14 | ||
15 | #include <asm/vdso.h> | |
16 | ||
17 | extern char vdso_start[], vdso_end[]; | |
18 | ||
19 | static unsigned int vdso_pages; | |
20 | static struct page **vdso_pagelist; | |
21 | ||
22 | /* | |
23 | * The vDSO data page. | |
24 | */ | |
25 | static union { | |
26 | struct vdso_data data; | |
27 | u8 page[PAGE_SIZE]; | |
28 | } vdso_data_store __page_aligned_data; | |
bf6df5dd | 29 | static struct vdso_data *vdso_data = &vdso_data_store.data; |
76d2a049 PD |
30 | |
31 | static int __init vdso_init(void) | |
32 | { | |
33 | unsigned int i; | |
34 | ||
35 | vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; | |
36 | vdso_pagelist = | |
37 | kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL); | |
38 | if (unlikely(vdso_pagelist == NULL)) { | |
39 | pr_err("vdso: pagelist allocation failed\n"); | |
40 | return -ENOMEM; | |
41 | } | |
42 | ||
43 | for (i = 0; i < vdso_pages; i++) { | |
44 | struct page *pg; | |
45 | ||
46 | pg = virt_to_page(vdso_start + (i << PAGE_SHIFT)); | |
76d2a049 PD |
47 | vdso_pagelist[i] = pg; |
48 | } | |
49 | vdso_pagelist[i] = virt_to_page(vdso_data); | |
50 | ||
51 | return 0; | |
52 | } | |
53 | arch_initcall(vdso_init); | |
54 | ||
55 | int arch_setup_additional_pages(struct linux_binprm *bprm, | |
56 | int uses_interp) | |
57 | { | |
58 | struct mm_struct *mm = current->mm; | |
59 | unsigned long vdso_base, vdso_len; | |
60 | int ret; | |
61 | ||
62 | vdso_len = (vdso_pages + 1) << PAGE_SHIFT; | |
63 | ||
d8ed45c5 | 64 | mmap_write_lock(mm); |
76d2a049 | 65 | vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0); |
509009cc | 66 | if (IS_ERR_VALUE(vdso_base)) { |
76d2a049 PD |
67 | ret = vdso_base; |
68 | goto end; | |
69 | } | |
70 | ||
71 | /* | |
72 | * Put vDSO base into mm struct. We need to do this before calling | |
73 | * install_special_mapping or the perf counter mmap tracking code | |
74 | * will fail to recognise it as a vDSO (since arch_vma_name fails). | |
75 | */ | |
76 | mm->context.vdso = (void *)vdso_base; | |
77 | ||
78 | ret = install_special_mapping(mm, vdso_base, vdso_len, | |
79 | (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC), | |
80 | vdso_pagelist); | |
81 | ||
82 | if (unlikely(ret)) | |
83 | mm->context.vdso = NULL; | |
84 | ||
85 | end: | |
d8ed45c5 | 86 | mmap_write_unlock(mm); |
76d2a049 PD |
87 | return ret; |
88 | } | |
89 | ||
90 | const char *arch_vma_name(struct vm_area_struct *vma) | |
91 | { | |
92 | if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso)) | |
93 | return "[vdso]"; | |
94 | return NULL; | |
95 | } |