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 15 #include <asm/processor.h> 16 #include <asm/vdso.h> 17 18 #ifdef CONFIG_COMPAT_VDSO 19 #define VDSO_DEFAULT 0 20 #else 21 #define VDSO_DEFAULT 1 22 #endif 23 24 /* 25 * Should the kernel map a VDSO page into processes and pass its 26 * address down to glibc upon exec()? 27 */ 28 unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT; 29 30 static int __init vdso32_setup(char *s) 31 { 32 vdso32_enabled = simple_strtoul(s, NULL, 0); 33 34 if (vdso32_enabled > 1) { 35 pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n"); 36 vdso32_enabled = 0; 37 } 38 39 return 1; 40 } 41 42 /* 43 * For consistency, the argument vdso32=[012] affects the 32-bit vDSO 44 * behavior on both 64-bit and 32-bit kernels. 45 * On 32-bit kernels, vdso=[012] means the same thing. 46 */ 47 __setup("vdso32=", vdso32_setup); 48 49 #ifdef CONFIG_X86_32 50 __setup_param("vdso=", vdso_setup, vdso32_setup, 0); 51 #endif 52 53 int __init sysenter_setup(void) 54 { 55 init_vdso_image(&vdso_image_32); 56 57 return 0; 58 } 59 60 #ifdef CONFIG_X86_64 61 62 subsys_initcall(sysenter_setup); 63 64 #ifdef CONFIG_SYSCTL 65 /* Register vsyscall32 into the ABI table */ 66 #include <linux/sysctl.h> 67 68 static const int zero; 69 static const int one = 1; 70 71 static struct ctl_table abi_table2[] = { 72 { 73 .procname = "vsyscall32", 74 .data = &vdso32_enabled, 75 .maxlen = sizeof(int), 76 .mode = 0644, 77 .proc_handler = proc_dointvec_minmax, 78 .extra1 = (int *)&zero, 79 .extra2 = (int *)&one, 80 }, 81 {} 82 }; 83 84 static struct ctl_table abi_root_table2[] = { 85 { 86 .procname = "abi", 87 .mode = 0555, 88 .child = abi_table2 89 }, 90 {} 91 }; 92 93 static __init int ia32_binfmt_init(void) 94 { 95 register_sysctl_table(abi_root_table2); 96 return 0; 97 } 98 __initcall(ia32_binfmt_init); 99 #endif /* CONFIG_SYSCTL */ 100 101 #endif /* CONFIG_X86_64 */ 102