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/cpufeature.h> 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 37 return 1; 38 } 39 40 /* 41 * For consistency, the argument vdso32=[012] affects the 32-bit vDSO 42 * behavior on both 64-bit and 32-bit kernels. 43 * On 32-bit kernels, vdso=[012] means the same thing. 44 */ 45 __setup("vdso32=", vdso32_setup); 46 47 #ifdef CONFIG_X86_32 48 __setup_param("vdso=", vdso_setup, vdso32_setup, 0); 49 #endif 50 51 int __init sysenter_setup(void) 52 { 53 init_vdso_image(&vdso_image_32); 54 55 return 0; 56 } 57 58 #ifdef CONFIG_X86_64 59 60 subsys_initcall(sysenter_setup); 61 62 #ifdef CONFIG_SYSCTL 63 /* Register vsyscall32 into the ABI table */ 64 #include <linux/sysctl.h> 65 66 static struct ctl_table abi_table2[] = { 67 { 68 .procname = "vsyscall32", 69 .data = &vdso32_enabled, 70 .maxlen = sizeof(int), 71 .mode = 0644, 72 .proc_handler = proc_dointvec 73 }, 74 {} 75 }; 76 77 static struct ctl_table abi_root_table2[] = { 78 { 79 .procname = "abi", 80 .mode = 0555, 81 .child = abi_table2 82 }, 83 {} 84 }; 85 86 static __init int ia32_binfmt_init(void) 87 { 88 register_sysctl_table(abi_root_table2); 89 return 0; 90 } 91 __initcall(ia32_binfmt_init); 92 #endif /* CONFIG_SYSCTL */ 93 94 #endif /* CONFIG_X86_64 */ 95