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 36 return 1; 37 } 38 39 /* 40 * For consistency, the argument vdso32=[012] affects the 32-bit vDSO 41 * behavior on both 64-bit and 32-bit kernels. 42 * On 32-bit kernels, vdso=[012] means the same thing. 43 */ 44 __setup("vdso32=", vdso32_setup); 45 46 #ifdef CONFIG_X86_32 47 __setup_param("vdso=", vdso_setup, vdso32_setup, 0); 48 #endif 49 50 int __init sysenter_setup(void) 51 { 52 init_vdso_image(&vdso_image_32); 53 54 return 0; 55 } 56 57 #ifdef CONFIG_X86_64 58 59 subsys_initcall(sysenter_setup); 60 61 #ifdef CONFIG_SYSCTL 62 /* Register vsyscall32 into the ABI table */ 63 #include <linux/sysctl.h> 64 65 static struct ctl_table abi_table2[] = { 66 { 67 .procname = "vsyscall32", 68 .data = &vdso32_enabled, 69 .maxlen = sizeof(int), 70 .mode = 0644, 71 .proc_handler = proc_dointvec 72 }, 73 {} 74 }; 75 76 static struct ctl_table abi_root_table2[] = { 77 { 78 .procname = "abi", 79 .mode = 0555, 80 .child = abi_table2 81 }, 82 {} 83 }; 84 85 static __init int ia32_binfmt_init(void) 86 { 87 register_sysctl_table(abi_root_table2); 88 return 0; 89 } 90 __initcall(ia32_binfmt_init); 91 #endif /* CONFIG_SYSCTL */ 92 93 #endif /* CONFIG_X86_64 */ 94