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kernel/linux-rt-4.4.41/arch/x86/um/vdso/vma.c 1.4 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/slab.h>
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <asm/page.h>
  #include <asm/elf.h>
  #include <linux/init.h>
  
  static unsigned int __read_mostly vdso_enabled = 1;
  unsigned long um_vdso_addr;
  
  extern unsigned long task_size;
  extern char vdso_start[], vdso_end[];
  
  static struct page **vdsop;
  
  static int __init init_vdso(void)
  {
  	struct page *um_vdso;
  
  	BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
  
  	um_vdso_addr = task_size - PAGE_SIZE;
  
  	vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL);
  	if (!vdsop)
  		goto oom;
  
  	um_vdso = alloc_page(GFP_KERNEL);
  	if (!um_vdso) {
  		kfree(vdsop);
  
  		goto oom;
  	}
  
  	copy_page(page_address(um_vdso), vdso_start);
  	*vdsop = um_vdso;
  
  	return 0;
  
  oom:
  	printk(KERN_ERR "Cannot allocate vdso
  ");
  	vdso_enabled = 0;
  
  	return -ENOMEM;
  }
  subsys_initcall(init_vdso);
  
  int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
  {
  	int err;
  	struct mm_struct *mm = current->mm;
  
  	if (!vdso_enabled)
  		return 0;
  
  	down_write(&mm->mmap_sem);
  
  	err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
  		VM_READ|VM_EXEC|
  		VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
  		vdsop);
  
  	up_write(&mm->mmap_sem);
  
  	return err;
  }