1 /* 2 * (C) Copyright 2002 Linus Torvalds 3 * Portions based on the vdso-randomization code from exec-shield: 4 * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar 5 * 6 * This file contains the needed initializations to support sysenter. 7 */ 8 9 #include <linux/init.h> 10 #include <linux/smp.h> 11 #include <linux/kernel.h> 12 #include <linux/mm_types.h> 13 14 #include <asm/processor.h> 15 #include <asm/vdso.h> 16 17 #ifdef CONFIG_COMPAT_VDSO 18 #define VDSO_DEFAULT 0 19 #else 20 #define VDSO_DEFAULT 1 21 #endif 22 23 /* 24 * Should the kernel map a VDSO page into processes and pass its 25 * address down to glibc upon exec()? 26 */ 27 unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT; 28 29 static int __init vdso32_setup(char *s) 30 { 31 vdso32_enabled = simple_strtoul(s, NULL, 0); 32 33 if (vdso32_enabled > 1) { 34 pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n"); 35 vdso32_enabled = 0; 36 } 37 38 return 1; 39 } 40 41 /* 42 * For consistency, the argument vdso32=[012] affects the 32-bit vDSO 43 * behavior on both 64-bit and 32-bit kernels. 44 * On 32-bit kernels, vdso=[012] means the same thing. 45 */ 46 __setup("vdso32=", vdso32_setup); 47 48 #ifdef CONFIG_X86_32 49 __setup_param("vdso=", vdso_setup, vdso32_setup, 0); 50 #endif 51 52 int __init sysenter_setup(void) 53 { 54 init_vdso_image(&vdso_image_32); 55 56 return 0; 57 } 58 59 #ifdef CONFIG_X86_64 60 61 subsys_initcall(sysenter_setup); 62 63 #ifdef CONFIG_SYSCTL 64 /* Register vsyscall32 into the ABI table */ 65 #include <linux/sysctl.h> 66 67 static const int zero; 68 static const int one = 1; 69 70 static struct ctl_table abi_table2[] = { 71 { 72 .procname = "vsyscall32", 73 .data = &vdso32_enabled, 74 .maxlen = sizeof(int), 75 .mode = 0644, 76 .proc_handler = proc_dointvec_minmax, 77 .extra1 = (int *)&zero, 78 .extra2 = (int *)&one, 79 }, 80 {} 81 }; 82 83 static struct ctl_table abi_root_table2[] = { 84 { 85 .procname = "abi", 86 .mode = 0555, 87 .child = abi_table2 88 }, 89 {} 90 }; 91 92 static __init int ia32_binfmt_init(void) 93 { 94 register_sysctl_table(abi_root_table2); 95 return 0; 96 } 97 __initcall(ia32_binfmt_init); 98 #endif /* CONFIG_SYSCTL */ 99 100 #endif /* CONFIG_X86_64 */ 101