Line data    Source code

       1             : // SPDX-License-Identifier: GPL-2.0-only
       2             : /*
       3             :  * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
       4             :  */
       5             : 
       6             : #include <linux/slab.h>
       7             : #include <linux/sched.h>
       8             : #include <linux/mm.h>
       9             : #include <asm/page.h>
      10             : #include <asm/elf.h>
      11             : #include <linux/init.h>
      12             : 
      13             : static unsigned int __read_mostly vdso_enabled = 1;
      14             : unsigned long um_vdso_addr;
      15             : 
      16             : extern unsigned long task_size;
      17             : extern char vdso_start[], vdso_end[];
      18             : 
      19             : static struct page **vdsop;
      20             : 
      21           1 : static int __init init_vdso(void)
      22             : {
      23             :         struct page *um_vdso;
      24             : 
      25           1 :         BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
      26             : 
      27           1 :         um_vdso_addr = task_size - PAGE_SIZE;
      28             : 
      29           1 :         vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL);
      30           1 :         if (!vdsop)
      31             :                 goto oom;
      32             : 
      33           1 :         um_vdso = alloc_page(GFP_KERNEL);
      34           1 :         if (!um_vdso) {
      35           0 :                 kfree(vdsop);
      36             : 
      37           0 :                 goto oom;
      38             :         }
      39             : 
      40           2 :         copy_page(page_address(um_vdso), vdso_start);
      41           1 :         *vdsop = um_vdso;
      42             : 
      43           1 :         return 0;
      44             : 
      45             : oom:
      46           0 :         printk(KERN_ERR "Cannot allocate vdso\n");
      47           0 :         vdso_enabled = 0;
      48             : 
      49           0 :         return -ENOMEM;
      50             : }
      51             : subsys_initcall(init_vdso);
      52             : 
      53           0 : int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
      54             : {
      55             :         int err;
      56           0 :         struct mm_struct *mm = current->mm;
      57             : 
      58           0 :         if (!vdso_enabled)
      59             :                 return 0;
      60             : 
      61           0 :         if (mmap_write_lock_killable(mm))
      62             :                 return -EINTR;
      63             : 
      64           0 :         err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
      65             :                 VM_READ|VM_EXEC|
      66             :                 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
      67             :                 vdsop);
      68             : 
      69           0 :         mmap_write_unlock(mm);
      70             : 
      71           0 :         return err;
      72             : }