1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
4 */
5
6 #include <linux/mm.h>
7 #include <asm/elf.h>
8
9 static struct vm_area_struct gate_vma;
10
11 static int __init gate_vma_init(void)
12 {
13 if (!FIXADDR_USER_START)
14 return 0;
15
16 vma_init(&gate_vma, NULL);
17 gate_vma.vm_start = FIXADDR_USER_START;
18 gate_vma.vm_end = FIXADDR_USER_END;
19 vm_flags_init(&gate_vma, VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC);
20 gate_vma.vm_page_prot = PAGE_READONLY;
21
22 return 0;
23 }
24 __initcall(gate_vma_init);
25
26 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
27 {
28 return FIXADDR_USER_START ? &gate_vma : NULL;
29 }
30
31 int in_gate_area_no_mm(unsigned long addr)
32 {
33 if (!FIXADDR_USER_START)
34 return 0;
35
36 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
37 return 1;
38
39 return 0;
40 }
41
42 int in_gate_area(struct mm_struct *mm, unsigned long addr)
43 {
44 struct vm_area_struct *vma = get_gate_vma(mm);
45
46 if (!vma)
47 return 0;
48
49 return (addr >= vma->vm_start) && (addr < vma->vm_end);
50 }
51
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