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/elf.h> 11 12 static struct vm_area_struct gate_vma; 13 14 static int __init gate_vma_init(void) 15 { 16 if (!FIXADDR_USER_START) 17 return 0; 18 19 gate_vma.vm_mm = NULL; 20 gate_vma.vm_start = FIXADDR_USER_START; 21 gate_vma.vm_end = FIXADDR_USER_END; 22 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; 23 gate_vma.vm_page_prot = __P101; 24 25 return 0; 26 } 27 __initcall(gate_vma_init); 28 29 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 30 { 31 return FIXADDR_USER_START ? &gate_vma : NULL; 32 } 33 34 int in_gate_area_no_mm(unsigned long addr) 35 { 36 if (!FIXADDR_USER_START) 37 return 0; 38 39 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 40 return 1; 41 42 return 0; 43 } 44 45 int in_gate_area(struct mm_struct *mm, unsigned long addr) 46 { 47 struct vm_area_struct *vma = get_gate_vma(mm); 48 49 if (!vma) 50 return 0; 51 52 return (addr >= vma->vm_start) && (addr < vma->vm_end); 53 } 54