1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only 2*4882a593Smuzhiyun /* 3*4882a593Smuzhiyun * Copyright (C) 2011 Richard Weinberger <richrd@nod.at> 4*4882a593Smuzhiyun */ 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun #include <linux/mm.h> 7*4882a593Smuzhiyun #include <asm/elf.h> 8*4882a593Smuzhiyun 9*4882a593Smuzhiyun static struct vm_area_struct gate_vma; 10*4882a593Smuzhiyun gate_vma_init(void)11*4882a593Smuzhiyunstatic int __init gate_vma_init(void) 12*4882a593Smuzhiyun { 13*4882a593Smuzhiyun if (!FIXADDR_USER_START) 14*4882a593Smuzhiyun return 0; 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun vma_init(&gate_vma, NULL); 17*4882a593Smuzhiyun gate_vma.vm_start = FIXADDR_USER_START; 18*4882a593Smuzhiyun gate_vma.vm_end = FIXADDR_USER_END; 19*4882a593Smuzhiyun gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; 20*4882a593Smuzhiyun gate_vma.vm_page_prot = __P101; 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun return 0; 23*4882a593Smuzhiyun } 24*4882a593Smuzhiyun __initcall(gate_vma_init); 25*4882a593Smuzhiyun get_gate_vma(struct mm_struct * mm)26*4882a593Smuzhiyunstruct vm_area_struct *get_gate_vma(struct mm_struct *mm) 27*4882a593Smuzhiyun { 28*4882a593Smuzhiyun return FIXADDR_USER_START ? &gate_vma : NULL; 29*4882a593Smuzhiyun } 30*4882a593Smuzhiyun in_gate_area_no_mm(unsigned long addr)31*4882a593Smuzhiyunint in_gate_area_no_mm(unsigned long addr) 32*4882a593Smuzhiyun { 33*4882a593Smuzhiyun if (!FIXADDR_USER_START) 34*4882a593Smuzhiyun return 0; 35*4882a593Smuzhiyun 36*4882a593Smuzhiyun if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 37*4882a593Smuzhiyun return 1; 38*4882a593Smuzhiyun 39*4882a593Smuzhiyun return 0; 40*4882a593Smuzhiyun } 41*4882a593Smuzhiyun in_gate_area(struct mm_struct * mm,unsigned long addr)42*4882a593Smuzhiyunint in_gate_area(struct mm_struct *mm, unsigned long addr) 43*4882a593Smuzhiyun { 44*4882a593Smuzhiyun struct vm_area_struct *vma = get_gate_vma(mm); 45*4882a593Smuzhiyun 46*4882a593Smuzhiyun if (!vma) 47*4882a593Smuzhiyun return 0; 48*4882a593Smuzhiyun 49*4882a593Smuzhiyun return (addr >= vma->vm_start) && (addr < vma->vm_end); 50*4882a593Smuzhiyun } 51