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// SPDX-License-Identifier: GPL-2.0
/*
* (C) Copyright 2002 Linus Torvalds
* Portions based on the vdso-randomization code from exec-shield:
* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
*
* This file contains the needed initializations to support sysenter.
*/
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/mm_types.h>
#include <linux/elf.h>
#include <asm/processor.h>
#include <asm/vdso.h>
#ifdef CONFIG_COMPAT_VDSO
#define VDSO_DEFAULT 0
#else
#define VDSO_DEFAULT 1
#endif
/*
* Should the kernel map a VDSO page into processes and pass its
* address down to glibc upon exec()?
*/
unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
static int __init vdso32_setup(char *s)
{
vdso32_enabled = simple_strtoul(s, NULL, 0);
if (vdso32_enabled > 1) {
pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n");
vdso32_enabled = 0;
}
return 1;
}
/*
* For consistency, the argument vdso32=[012] affects the 32-bit vDSO
* behavior on both 64-bit and 32-bit kernels.
* On 32-bit kernels, vdso=[012] means the same thing.
*/
__setup("vdso32=", vdso32_setup);
#ifdef CONFIG_X86_32
__setup_param("vdso=", vdso_setup, vdso32_setup, 0);
#endif
#ifdef CONFIG_X86_64
#ifdef CONFIG_SYSCTL
/* Register vsyscall32 into the ABI table */
#include <linux/sysctl.h>
static struct ctl_table abi_table2[] = {
{
.procname = "vsyscall32",
.data = &vdso32_enabled,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
};
static __init int ia32_binfmt_init(void)
{
register_sysctl("abi", abi_table2);
return 0;
}
__initcall(ia32_binfmt_init);
#endif /* CONFIG_SYSCTL */
#endif /* CONFIG_X86_64 */
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