cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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vdso32-setup.c (2023B)

      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 */
     29unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
     30
     31static 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
     54int __init sysenter_setup(void)
     55{
     56	init_vdso_image(&vdso_image_32);
     57
     58	return 0;
     59}
     60
     61#ifdef CONFIG_X86_64
     62
     63subsys_initcall(sysenter_setup);
     64
     65#ifdef CONFIG_SYSCTL
     66/* Register vsyscall32 into the ABI table */
     67#include <linux/sysctl.h>
     68
     69static struct ctl_table abi_table2[] = {
     70	{
     71		.procname	= "vsyscall32",
     72		.data		= &vdso32_enabled,
     73		.maxlen		= sizeof(int),
     74		.mode		= 0644,
     75		.proc_handler	= proc_dointvec_minmax,
     76		.extra1		= SYSCTL_ZERO,
     77		.extra2		= SYSCTL_ONE,
     78	},
     79	{}
     80};
     81
     82static struct ctl_table abi_root_table2[] = {
     83	{
     84		.procname = "abi",
     85		.mode = 0555,
     86		.child = abi_table2
     87	},
     88	{}
     89};
     90
     91static __init int ia32_binfmt_init(void)
     92{
     93	register_sysctl_table(abi_root_table2);
     94	return 0;
     95}
     96__initcall(ia32_binfmt_init);
     97#endif /* CONFIG_SYSCTL */
     98
     99#endif	/* CONFIG_X86_64 */