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 gate_vma.vm_flags = 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