| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 */ |