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
9static struct vm_area_struct gate_vma;
10
11static 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
26struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
27{
28	return FIXADDR_USER_START ? &gate_vma : NULL;
29}
30
31int 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
42int 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