/*
* (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 <asm/cpufeature.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");
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
#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SYSENTER32))
#define vdso32_syscall() (boot_cpu_has(X86_FEATURE_SYSCALL32))
#else /* CONFIG_X86_32 */
#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SEP))
#define vdso32_syscall() (0)
#endif /* CONFIG_X86_64 */
#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
const struct vdso_image *selected_vdso32;
#endif
int __init sysenter_setup(void)
{
#ifdef CONFIG_COMPAT
if (vdso32_syscall())
selected_vdso32 = &vdso_image_32_syscall;
else
#endif
if (vdso32_sysenter())
selected_vdso32 = &vdso_image_32_sysenter;
else
selected_vdso32 = &vdso_image_32_int80;
init_vdso_image(selected_vdso32);
return 0;
}
#ifdef CONFIG_X86_64
subsys_initcall(sysenter_setup);
#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
},
{}
};
static struct ctl_table abi_root_table2[] = {
{
.procname = "abi",
.mode = 0555,
.child = abi_table2
},
{}
};
static __init int ia32_binfmt_init(void)
{
register_sysctl_table(abi_root_table2);
return 0;
}
__initcall(ia32_binfmt_init);
#endif /* CONFIG_SYSCTL */
#endif /* CONFIG_X86_64 */
