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 #ifdef GENERIC_TIME_VSYSCALL
12 #include <vdso/datapage.h>
13 #else
14 #include <asm/vdso.h>
15 #endif
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;
29 struct vdso_data *vdso_data = &vdso_data_store.data;
30
vdso_init(void)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));
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
arch_setup_additional_pages(struct linux_binprm * bprm,int uses_interp)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
64 mmap_write_lock(mm);
65 vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
66 if (IS_ERR_VALUE(vdso_base)) {
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 =
79 install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
80 (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
81 vdso_pagelist);
82
83 if (unlikely(ret)) {
84 mm->context.vdso = NULL;
85 goto end;
86 }
87
88 vdso_base += (vdso_pages << PAGE_SHIFT);
89 ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
90 (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);
91
92 if (unlikely(ret))
93 mm->context.vdso = NULL;
94 end:
95 mmap_write_unlock(mm);
96 return ret;
97 }
98
arch_vma_name(struct vm_area_struct * vma)99 const char *arch_vma_name(struct vm_area_struct *vma)
100 {
101 if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
102 return "[vdso]";
103 if (vma->vm_mm && (vma->vm_start ==
104 (long)vma->vm_mm->context.vdso + PAGE_SIZE))
105 return "[vdso_data]";
106 return NULL;
107 }
108
