| /* |
| * 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 <linux/init.h> |
| |
| 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(GFP_KERNEL, sizeof(struct page *)); |
| 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\n"); |
| 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| |
| VM_ALWAYSDUMP, |
| vdsop); |
| |
| up_write(&mm->mmap_sem); |
| |
| return err; |
| } |