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