1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * (C) Copyright 2002 Linus Torvalds
4*4882a593Smuzhiyun * Portions based on the vdso-randomization code from exec-shield:
5*4882a593Smuzhiyun * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * This file contains the needed initializations to support sysenter.
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <linux/init.h>
11*4882a593Smuzhiyun #include <linux/smp.h>
12*4882a593Smuzhiyun #include <linux/kernel.h>
13*4882a593Smuzhiyun #include <linux/mm_types.h>
14*4882a593Smuzhiyun #include <linux/elf.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include <asm/processor.h>
17*4882a593Smuzhiyun #include <asm/vdso.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #ifdef CONFIG_COMPAT_VDSO
20*4882a593Smuzhiyun #define VDSO_DEFAULT 0
21*4882a593Smuzhiyun #else
22*4882a593Smuzhiyun #define VDSO_DEFAULT 1
23*4882a593Smuzhiyun #endif
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun /*
26*4882a593Smuzhiyun * Should the kernel map a VDSO page into processes and pass its
27*4882a593Smuzhiyun * address down to glibc upon exec()?
28*4882a593Smuzhiyun */
29*4882a593Smuzhiyun unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
30*4882a593Smuzhiyun
vdso32_setup(char * s)31*4882a593Smuzhiyun static int __init vdso32_setup(char *s)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun vdso32_enabled = simple_strtoul(s, NULL, 0);
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun if (vdso32_enabled > 1) {
36*4882a593Smuzhiyun pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n");
37*4882a593Smuzhiyun vdso32_enabled = 0;
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun return 1;
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun /*
44*4882a593Smuzhiyun * For consistency, the argument vdso32=[012] affects the 32-bit vDSO
45*4882a593Smuzhiyun * behavior on both 64-bit and 32-bit kernels.
46*4882a593Smuzhiyun * On 32-bit kernels, vdso=[012] means the same thing.
47*4882a593Smuzhiyun */
48*4882a593Smuzhiyun __setup("vdso32=", vdso32_setup);
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun #ifdef CONFIG_X86_32
51*4882a593Smuzhiyun __setup_param("vdso=", vdso_setup, vdso32_setup, 0);
52*4882a593Smuzhiyun #endif
53*4882a593Smuzhiyun
sysenter_setup(void)54*4882a593Smuzhiyun int __init sysenter_setup(void)
55*4882a593Smuzhiyun {
56*4882a593Smuzhiyun init_vdso_image(&vdso_image_32);
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun return 0;
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun #ifdef CONFIG_X86_64
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun subsys_initcall(sysenter_setup);
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun #ifdef CONFIG_SYSCTL
66*4882a593Smuzhiyun /* Register vsyscall32 into the ABI table */
67*4882a593Smuzhiyun #include <linux/sysctl.h>
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun static struct ctl_table abi_table2[] = {
70*4882a593Smuzhiyun {
71*4882a593Smuzhiyun .procname = "vsyscall32",
72*4882a593Smuzhiyun .data = &vdso32_enabled,
73*4882a593Smuzhiyun .maxlen = sizeof(int),
74*4882a593Smuzhiyun .mode = 0644,
75*4882a593Smuzhiyun .proc_handler = proc_dointvec_minmax,
76*4882a593Smuzhiyun .extra1 = SYSCTL_ZERO,
77*4882a593Smuzhiyun .extra2 = SYSCTL_ONE,
78*4882a593Smuzhiyun },
79*4882a593Smuzhiyun {}
80*4882a593Smuzhiyun };
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun static struct ctl_table abi_root_table2[] = {
83*4882a593Smuzhiyun {
84*4882a593Smuzhiyun .procname = "abi",
85*4882a593Smuzhiyun .mode = 0555,
86*4882a593Smuzhiyun .child = abi_table2
87*4882a593Smuzhiyun },
88*4882a593Smuzhiyun {}
89*4882a593Smuzhiyun };
90*4882a593Smuzhiyun
ia32_binfmt_init(void)91*4882a593Smuzhiyun static __init int ia32_binfmt_init(void)
92*4882a593Smuzhiyun {
93*4882a593Smuzhiyun register_sysctl_table(abi_root_table2);
94*4882a593Smuzhiyun return 0;
95*4882a593Smuzhiyun }
96*4882a593Smuzhiyun __initcall(ia32_binfmt_init);
97*4882a593Smuzhiyun #endif /* CONFIG_SYSCTL */
98*4882a593Smuzhiyun
99*4882a593Smuzhiyun #endif /* CONFIG_X86_64 */
100