1 // SPDX-License-Identifier: GPL-2.0
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
7 * This file contains the needed initializations to support sysenter.
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>
16 #include <asm/processor.h>
19 #ifdef CONFIG_COMPAT_VDSO
20 #define VDSO_DEFAULT 0
22 #define VDSO_DEFAULT 1
26 * Should the kernel map a VDSO page into processes and pass its
27 * address down to glibc upon exec()?
29 unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
31 static int __init vdso32_setup(char *s)
33 vdso32_enabled = simple_strtoul(s, NULL, 0);
35 if (vdso32_enabled > 1) {
36 pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n");
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.
48 __setup("vdso32=", vdso32_setup);
51 __setup_param("vdso=", vdso_setup, vdso32_setup, 0);
54 int __init sysenter_setup(void)
56 init_vdso_image(&vdso_image_32);
63 subsys_initcall(sysenter_setup);
66 /* Register vsyscall32 into the ABI table */
67 #include <linux/sysctl.h>
69 static const int zero;
70 static const int one = 1;
72 static struct ctl_table abi_table2[] = {
74 .procname = "vsyscall32",
75 .data = &vdso32_enabled,
76 .maxlen = sizeof(int),
78 .proc_handler = proc_dointvec_minmax,
79 .extra1 = (int *)&zero,
80 .extra2 = (int *)&one,
85 static struct ctl_table abi_root_table2[] = {
94 static __init int ia32_binfmt_init(void)
96 register_sysctl_table(abi_root_table2);
99 __initcall(ia32_binfmt_init);
100 #endif /* CONFIG_SYSCTL */
102 #endif /* CONFIG_X86_64 */