arch/x86/um/mem_32.c

   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 }