1 /* 2 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #include <linux/mm.h> 10 #include <asm/page.h> 11 #include <asm/mman.h> 12 13 static struct vm_area_struct gate_vma; 14 15 static int __init gate_vma_init(void) 16 { 17 if (!FIXADDR_USER_START) 18 return 0; 19 20 gate_vma.vm_mm = NULL; 21 gate_vma.vm_start = FIXADDR_USER_START; 22 gate_vma.vm_end = FIXADDR_USER_END; 23 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; 24 gate_vma.vm_page_prot = __P101; 25 26 return 0; 27 } 28 __initcall(gate_vma_init); 29 30 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 31 { 32 return FIXADDR_USER_START ? &gate_vma : NULL; 33 } 34 35 int in_gate_area_no_mm(unsigned long addr) 36 { 37 if (!FIXADDR_USER_START) 38 return 0; 39 40 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 41 return 1; 42 43 return 0; 44 } 45 46 int in_gate_area(struct mm_struct *mm, unsigned long addr) 47 { 48 struct vm_area_struct *vma = get_gate_vma(mm); 49 50 if (!vma) 51 return 0; 52 53 return (addr >= vma->vm_start) && (addr < vma->vm_end); 54 } 55