source: src/linux/universal/linux-4.4/arch/x86/entry/vdso/vdso32-setup.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 3 months ago

update

File size: 2.0 KB
Line 
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 */
28unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
29
30static 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                vdso32_enabled = 0;
37        }
38
39        return 1;
40}
41
42/*
43 * For consistency, the argument vdso32=[012] affects the 32-bit vDSO
44 * behavior on both 64-bit and 32-bit kernels.
45 * On 32-bit kernels, vdso=[012] means the same thing.
46 */
47__setup("vdso32=", vdso32_setup);
48
49#ifdef CONFIG_X86_32
50__setup_param("vdso=", vdso_setup, vdso32_setup, 0);
51#endif
52
53int __init sysenter_setup(void)
54{
55        init_vdso_image(&vdso_image_32);
56
57        return 0;
58}
59
60#ifdef CONFIG_X86_64
61
62subsys_initcall(sysenter_setup);
63
64#ifdef CONFIG_SYSCTL
65/* Register vsyscall32 into the ABI table */
66#include <linux/sysctl.h>
67
68static const int zero;
69static const int one = 1;
70
71static struct ctl_table abi_table2[] = {
72        {
73                .procname       = "vsyscall32",
74                .data           = &vdso32_enabled,
75                .maxlen         = sizeof(int),
76                .mode           = 0644,
77                .proc_handler   = proc_dointvec_minmax,
78                .extra1         = (int *)&zero,
79                .extra2         = (int *)&one,
80        },
81        {}
82};
83
84static struct ctl_table abi_root_table2[] = {
85        {
86                .procname = "abi",
87                .mode = 0555,
88                .child = abi_table2
89        },
90        {}
91};
92
93static __init int ia32_binfmt_init(void)
94{
95        register_sysctl_table(abi_root_table2);
96        return 0;
97}
98__initcall(ia32_binfmt_init);
99#endif /* CONFIG_SYSCTL */
100
101#endif  /* CONFIG_X86_64 */
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