| 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(vma: &gate_vma, NULL); |
| 17 | gate_vma.vm_start = FIXADDR_USER_START; |
| 18 | gate_vma.vm_end = FIXADDR_USER_END; |
| 19 | vm_flags_init(vma: &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 |