blob: e5cdfd603f8fb6dabbdf22051b043604c8ad6496 [file] [log] [blame]
David Daneyc52d0d32010-02-18 16:13:04 -08001/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2009, 2010 Cavium Networks, Inc.
7 */
8
9
10#include <linux/kernel.h>
11#include <linux/err.h>
12#include <linux/sched.h>
13#include <linux/mm.h>
14#include <linux/init.h>
15#include <linux/binfmts.h>
16#include <linux/elf.h>
17#include <linux/vmalloc.h>
18#include <linux/unistd.h>
19
20#include <asm/vdso.h>
21#include <asm/uasm.h>
22
23/*
24 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
25 */
26#define __NR_O32_sigreturn 4119
27#define __NR_O32_rt_sigreturn 4193
28#define __NR_N32_rt_sigreturn 6211
29
30static struct page *vdso_page;
31
32static void __init install_trampoline(u32 *tramp, unsigned int sigreturn)
33{
34 uasm_i_addiu(&tramp, 2, 0, sigreturn); /* li v0, sigreturn */
35 uasm_i_syscall(&tramp, 0);
36}
37
38static int __init init_vdso(void)
39{
40 struct mips_vdso *vdso;
41
42 vdso_page = alloc_page(GFP_KERNEL);
43 if (!vdso_page)
44 panic("Cannot allocate vdso");
45
46 vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
47 if (!vdso)
48 panic("Cannot map vdso");
49 clear_page(vdso);
50
51 install_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn);
52#ifdef CONFIG_32BIT
53 install_trampoline(vdso->signal_trampoline, __NR_sigreturn);
54#else
55 install_trampoline(vdso->n32_rt_signal_trampoline,
56 __NR_N32_rt_sigreturn);
57 install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn);
58 install_trampoline(vdso->o32_rt_signal_trampoline,
59 __NR_O32_rt_sigreturn);
60#endif
61
62 vunmap(vdso);
63
David Daneyc52d0d32010-02-18 16:13:04 -080064 return 0;
65}
David Daney1ed84532010-06-16 15:00:28 -070066subsys_initcall(init_vdso);
David Daneyc52d0d32010-02-18 16:13:04 -080067
68static unsigned long vdso_addr(unsigned long start)
69{
70 return STACK_TOP;
71}
72
73int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
74{
75 int ret;
76 unsigned long addr;
77 struct mm_struct *mm = current->mm;
78
79 down_write(&mm->mmap_sem);
80
81 addr = vdso_addr(mm->start_stack);
82
83 addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0);
84 if (IS_ERR_VALUE(addr)) {
85 ret = addr;
86 goto up_fail;
87 }
88
89 ret = install_special_mapping(mm, addr, PAGE_SIZE,
90 VM_READ|VM_EXEC|
91 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
92 VM_ALWAYSDUMP,
93 &vdso_page);
94
95 if (ret)
96 goto up_fail;
97
98 mm->context.vdso = (void *)addr;
99
100up_fail:
101 up_write(&mm->mmap_sem);
102 return ret;
103}
104
105const char *arch_vma_name(struct vm_area_struct *vma)
106{
107 if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
108 return "[vdso]";
109 return NULL;
110}