1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
4 */
5
6 #include <linux/slab.h>
7 #include <linux/sched.h>
8 #include <linux/mm.h>
9 #include <asm/page.h>
10 #include <asm/elf.h>
11 #include <linux/init.h>
12
13 unsigned long um_vdso_addr;
14 static struct page *um_vdso;
15
16 extern unsigned long task_size;
17 extern char vdso_start[], vdso_end[];
18
init_vdso(void)19 static int __init init_vdso(void)
20 {
21 BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
22
23 um_vdso_addr = task_size - PAGE_SIZE;
24
25 um_vdso = alloc_page(GFP_KERNEL);
26 if (!um_vdso)
27 panic("Cannot allocate vdso\n");
28
29 copy_page(page_address(um_vdso), vdso_start);
30
31 return 0;
32 }
33 subsys_initcall(init_vdso);
34
arch_setup_additional_pages(struct linux_binprm * bprm,int uses_interp)35 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
36 {
37 struct vm_area_struct *vma;
38 struct mm_struct *mm = current->mm;
39 static struct vm_special_mapping vdso_mapping = {
40 .name = "[vdso]",
41 .pages = &um_vdso,
42 };
43
44 if (mmap_write_lock_killable(mm))
45 return -EINTR;
46
47 vma = _install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
48 VM_READ|VM_EXEC|
49 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
50 &vdso_mapping);
51
52 mmap_write_unlock(mm);
53
54 return IS_ERR(vma) ? PTR_ERR(vma) : 0;
55 }
56