Richard Weinberger | f1c2bb8 | 2011-07-25 17:12:54 -0700 | [diff] [blame] | 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/slab.h> |
| 10 | #include <linux/sched.h> |
| 11 | #include <linux/mm.h> |
| 12 | #include <asm/page.h> |
| 13 | #include <linux/init.h> |
| 14 | |
| 15 | unsigned int __read_mostly vdso_enabled = 1; |
| 16 | unsigned long um_vdso_addr; |
| 17 | |
| 18 | extern unsigned long task_size; |
| 19 | extern char vdso_start[], vdso_end[]; |
| 20 | |
| 21 | static struct page **vdsop; |
| 22 | |
| 23 | static int __init init_vdso(void) |
| 24 | { |
| 25 | struct page *um_vdso; |
| 26 | |
| 27 | BUG_ON(vdso_end - vdso_start > PAGE_SIZE); |
| 28 | |
| 29 | um_vdso_addr = task_size - PAGE_SIZE; |
| 30 | |
Dave Jones | 0d65ede | 2011-10-24 18:15:32 -0400 | [diff] [blame] | 31 | vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL); |
Richard Weinberger | f1c2bb8 | 2011-07-25 17:12:54 -0700 | [diff] [blame] | 32 | if (!vdsop) |
| 33 | goto oom; |
| 34 | |
| 35 | um_vdso = alloc_page(GFP_KERNEL); |
| 36 | if (!um_vdso) { |
| 37 | kfree(vdsop); |
| 38 | |
| 39 | goto oom; |
| 40 | } |
| 41 | |
| 42 | copy_page(page_address(um_vdso), vdso_start); |
| 43 | *vdsop = um_vdso; |
| 44 | |
| 45 | return 0; |
| 46 | |
| 47 | oom: |
| 48 | printk(KERN_ERR "Cannot allocate vdso\n"); |
| 49 | vdso_enabled = 0; |
| 50 | |
| 51 | return -ENOMEM; |
| 52 | } |
| 53 | subsys_initcall(init_vdso); |
| 54 | |
| 55 | int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) |
| 56 | { |
| 57 | int err; |
| 58 | struct mm_struct *mm = current->mm; |
| 59 | |
| 60 | if (!vdso_enabled) |
| 61 | return 0; |
| 62 | |
| 63 | down_write(&mm->mmap_sem); |
| 64 | |
| 65 | err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE, |
| 66 | VM_READ|VM_EXEC| |
| 67 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| |
| 68 | VM_ALWAYSDUMP, |
| 69 | vdsop); |
| 70 | |
| 71 | up_write(&mm->mmap_sem); |
| 72 | |
| 73 | return err; |
| 74 | } |