1 /*
2 * (C) Copyright 2002 Linus Torvalds
3 * Portions based on the vdso-randomization code from exec-shield:
4 * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
5 *
6 * This file contains the needed initializations to support sysenter.
7 */
8
9 #include <linux/init.h>
10 #include <linux/smp.h>
11 #include <linux/kernel.h>
12 #include <linux/mm_types.h>
13
14 #include <asm/cpufeature.h>
15 #include <asm/processor.h>
16 #include <asm/vdso.h>
17
18 #ifdef CONFIG_COMPAT_VDSO
19 #define VDSO_DEFAULT 0
20 #else
21 #define VDSO_DEFAULT 1
22 #endif
23
24 /*
25 * Should the kernel map a VDSO page into processes and pass its
26 * address down to glibc upon exec()?
27 */
28 unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
29
vdso32_setup(char * s)30 static int __init vdso32_setup(char *s)
31 {
32 vdso32_enabled = simple_strtoul(s, NULL, 0);
33
34 if (vdso32_enabled > 1)
35 pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n");
36
37 return 1;
38 }
39
40 /*
41 * For consistency, the argument vdso32=[012] affects the 32-bit vDSO
42 * behavior on both 64-bit and 32-bit kernels.
43 * On 32-bit kernels, vdso=[012] means the same thing.
44 */
45 __setup("vdso32=", vdso32_setup);
46
47 #ifdef CONFIG_X86_32
48 __setup_param("vdso=", vdso_setup, vdso32_setup, 0);
49 #endif
50
sysenter_setup(void)51 int __init sysenter_setup(void)
52 {
53 init_vdso_image(&vdso_image_32);
54
55 return 0;
56 }
57
58 #ifdef CONFIG_X86_64
59
60 subsys_initcall(sysenter_setup);
61
62 #ifdef CONFIG_SYSCTL
63 /* Register vsyscall32 into the ABI table */
64 #include <linux/sysctl.h>
65
66 static struct ctl_table abi_table2[] = {
67 {
68 .procname = "vsyscall32",
69 .data = &vdso32_enabled,
70 .maxlen = sizeof(int),
71 .mode = 0644,
72 .proc_handler = proc_dointvec
73 },
74 {}
75 };
76
77 static struct ctl_table abi_root_table2[] = {
78 {
79 .procname = "abi",
80 .mode = 0555,
81 .child = abi_table2
82 },
83 {}
84 };
85
ia32_binfmt_init(void)86 static __init int ia32_binfmt_init(void)
87 {
88 register_sysctl_table(abi_root_table2);
89 return 0;
90 }
91 __initcall(ia32_binfmt_init);
92 #endif /* CONFIG_SYSCTL */
93
94 #endif /* CONFIG_X86_64 */
95