Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Andy Lutomirski | 95c46b5 | 2014-10-29 14:33:46 -0700 | [diff] [blame] | 2 | * Copyright (c) 2012-2014 Andy Lutomirski <luto@amacapital.net> |
| 3 | * |
| 4 | * Based on the original implementation which is: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE |
| 6 | * Copyright 2003 Andi Kleen, SuSE Labs. |
| 7 | * |
Andy Lutomirski | 95c46b5 | 2014-10-29 14:33:46 -0700 | [diff] [blame] | 8 | * Parts of the original code have been moved to arch/x86/vdso/vma.c |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 9 | * |
Andy Lutomirski | 95c46b5 | 2014-10-29 14:33:46 -0700 | [diff] [blame] | 10 | * This file implements vsyscall emulation. vsyscalls are a legacy ABI: |
| 11 | * Userspace can request certain kernel services by calling fixed |
| 12 | * addresses. This concept is problematic: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | * |
Andy Lutomirski | 95c46b5 | 2014-10-29 14:33:46 -0700 | [diff] [blame] | 14 | * - It interferes with ASLR. |
| 15 | * - It's awkward to write code that lives in kernel addresses but is |
| 16 | * callable by userspace at fixed addresses. |
| 17 | * - The whole concept is impossible for 32-bit compat userspace. |
| 18 | * - UML cannot easily virtualize a vsyscall. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | * |
Andy Lutomirski | 95c46b5 | 2014-10-29 14:33:46 -0700 | [diff] [blame] | 20 | * As of mid-2014, I believe that there is no new userspace code that |
| 21 | * will use a vsyscall if the vDSO is present. I hope that there will |
| 22 | * soon be no new userspace code that will ever use a vsyscall. |
| 23 | * |
| 24 | * The code in this file emulates vsyscalls when notified of a page |
| 25 | * fault to a vsyscall address. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | */ |
| 27 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <linux/kernel.h> |
| 29 | #include <linux/timer.h> |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 30 | #include <linux/syscalls.h> |
| 31 | #include <linux/ratelimit.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
| 33 | #include <asm/vsyscall.h> |
john stultz | 7460ed2 | 2007-02-16 01:28:21 -0800 | [diff] [blame] | 34 | #include <asm/unistd.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <asm/fixmap.h> |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 36 | #include <asm/traps.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | |
Andy Lutomirski | c149a66 | 2011-08-03 09:31:54 -0400 | [diff] [blame] | 38 | #define CREATE_TRACE_POINTS |
| 39 | #include "vsyscall_trace.h" |
| 40 | |
Kees Cook | 3dc33bd | 2015-08-12 17:55:19 -0700 | [diff] [blame] | 41 | static enum { EMULATE, NATIVE, NONE } vsyscall_mode = |
Borislav Petkov | 93f13a9 | 2015-09-21 09:48:29 +0200 | [diff] [blame] | 42 | #if defined(CONFIG_LEGACY_VSYSCALL_NATIVE) |
Kees Cook | 3dc33bd | 2015-08-12 17:55:19 -0700 | [diff] [blame] | 43 | NATIVE; |
Borislav Petkov | 93f13a9 | 2015-09-21 09:48:29 +0200 | [diff] [blame] | 44 | #elif defined(CONFIG_LEGACY_VSYSCALL_NONE) |
Kees Cook | 3dc33bd | 2015-08-12 17:55:19 -0700 | [diff] [blame] | 45 | NONE; |
| 46 | #else |
| 47 | EMULATE; |
| 48 | #endif |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 49 | |
| 50 | static int __init vsyscall_setup(char *str) |
| 51 | { |
| 52 | if (str) { |
| 53 | if (!strcmp("emulate", str)) |
| 54 | vsyscall_mode = EMULATE; |
| 55 | else if (!strcmp("native", str)) |
| 56 | vsyscall_mode = NATIVE; |
| 57 | else if (!strcmp("none", str)) |
| 58 | vsyscall_mode = NONE; |
| 59 | else |
| 60 | return -EINVAL; |
| 61 | |
| 62 | return 0; |
| 63 | } |
| 64 | |
| 65 | return -EINVAL; |
| 66 | } |
| 67 | early_param("vsyscall", vsyscall_setup); |
| 68 | |
Borislav Petkov | beca4e2 | 2018-01-04 17:42:45 +0100 | [diff] [blame] | 69 | bool vsyscall_enabled(void) |
| 70 | { |
| 71 | return vsyscall_mode != NONE; |
| 72 | } |
| 73 | |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 74 | static void warn_bad_vsyscall(const char *level, struct pt_regs *regs, |
| 75 | const char *message) |
| 76 | { |
Joe Perches | c767a54 | 2012-05-21 19:50:07 -0700 | [diff] [blame] | 77 | if (!show_unhandled_signals) |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 78 | return; |
| 79 | |
Andy Lutomirski | 53b884a | 2014-07-25 16:30:27 -0700 | [diff] [blame] | 80 | printk_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n", |
| 81 | level, current->comm, task_pid_nr(current), |
| 82 | message, regs->ip, regs->cs, |
| 83 | regs->sp, regs->ax, regs->si, regs->di); |
Andy Lutomirski | c971294 | 2011-07-13 09:24:09 -0400 | [diff] [blame] | 84 | } |
| 85 | |
| 86 | static int addr_to_vsyscall_nr(unsigned long addr) |
| 87 | { |
| 88 | int nr; |
| 89 | |
Andy Lutomirski | f40c330 | 2014-05-05 12:19:36 -0700 | [diff] [blame] | 90 | if ((addr & ~0xC00UL) != VSYSCALL_ADDR) |
Andy Lutomirski | c971294 | 2011-07-13 09:24:09 -0400 | [diff] [blame] | 91 | return -EINVAL; |
| 92 | |
| 93 | nr = (addr & 0xC00UL) >> 10; |
| 94 | if (nr >= 3) |
| 95 | return -EINVAL; |
| 96 | |
| 97 | return nr; |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 98 | } |
| 99 | |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 100 | static bool write_ok_or_segv(unsigned long ptr, size_t size) |
| 101 | { |
| 102 | /* |
| 103 | * XXX: if access_ok, get_user, and put_user handled |
Ingo Molnar | 2a53ccb | 2016-07-15 10:21:11 +0200 | [diff] [blame] | 104 | * sig_on_uaccess_err, this could go away. |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 105 | */ |
| 106 | |
| 107 | if (!access_ok(VERIFY_WRITE, (void __user *)ptr, size)) { |
| 108 | siginfo_t info; |
| 109 | struct thread_struct *thread = ¤t->thread; |
| 110 | |
| 111 | thread->error_code = 6; /* user fault, no page, write */ |
| 112 | thread->cr2 = ptr; |
Srikar Dronamraju | 51e7dc7 | 2012-03-12 14:55:55 +0530 | [diff] [blame] | 113 | thread->trap_nr = X86_TRAP_PF; |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 114 | |
| 115 | memset(&info, 0, sizeof(info)); |
| 116 | info.si_signo = SIGSEGV; |
| 117 | info.si_errno = 0; |
| 118 | info.si_code = SEGV_MAPERR; |
| 119 | info.si_addr = (void __user *)ptr; |
| 120 | |
| 121 | force_sig_info(SIGSEGV, &info, current); |
| 122 | return false; |
| 123 | } else { |
| 124 | return true; |
| 125 | } |
| 126 | } |
| 127 | |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 128 | bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 129 | { |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 130 | struct task_struct *tsk; |
| 131 | unsigned long caller; |
Andy Lutomirski | 87b526d | 2012-10-01 11:40:45 -0700 | [diff] [blame] | 132 | int vsyscall_nr, syscall_nr, tmp; |
Ingo Molnar | 2a53ccb | 2016-07-15 10:21:11 +0200 | [diff] [blame] | 133 | int prev_sig_on_uaccess_err; |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 134 | long ret; |
| 135 | |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 136 | /* |
| 137 | * No point in checking CS -- the only way to get here is a user mode |
| 138 | * trap to a high address, which means that we're in 64-bit user code. |
| 139 | */ |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 140 | |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 141 | WARN_ON_ONCE(address != regs->ip); |
Andy Lutomirski | c971294 | 2011-07-13 09:24:09 -0400 | [diff] [blame] | 142 | |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 143 | if (vsyscall_mode == NONE) { |
| 144 | warn_bad_vsyscall(KERN_INFO, regs, |
| 145 | "vsyscall attempted with vsyscall=none"); |
| 146 | return false; |
Andy Lutomirski | c971294 | 2011-07-13 09:24:09 -0400 | [diff] [blame] | 147 | } |
| 148 | |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 149 | vsyscall_nr = addr_to_vsyscall_nr(address); |
Andy Lutomirski | c149a66 | 2011-08-03 09:31:54 -0400 | [diff] [blame] | 150 | |
| 151 | trace_emulate_vsyscall(vsyscall_nr); |
| 152 | |
Andy Lutomirski | c971294 | 2011-07-13 09:24:09 -0400 | [diff] [blame] | 153 | if (vsyscall_nr < 0) { |
| 154 | warn_bad_vsyscall(KERN_WARNING, regs, |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 155 | "misaligned vsyscall (exploit attempt or buggy program) -- look up the vsyscall kernel parameter if you need a workaround"); |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 156 | goto sigsegv; |
| 157 | } |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 158 | |
| 159 | if (get_user(caller, (unsigned long __user *)regs->sp) != 0) { |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 160 | warn_bad_vsyscall(KERN_WARNING, regs, |
| 161 | "vsyscall with bad stack (exploit attempt?)"); |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 162 | goto sigsegv; |
| 163 | } |
| 164 | |
| 165 | tsk = current; |
Andy Lutomirski | 87b526d | 2012-10-01 11:40:45 -0700 | [diff] [blame] | 166 | |
| 167 | /* |
| 168 | * Check for access_ok violations and find the syscall nr. |
| 169 | * |
| 170 | * NULL is a valid user pointer (in the access_ok sense) on 32-bit and |
| 171 | * 64-bit, so we don't need to special-case it here. For all the |
| 172 | * vsyscalls, NULL means "don't write anything" not "write it at |
| 173 | * address 0". |
| 174 | */ |
| 175 | switch (vsyscall_nr) { |
| 176 | case 0: |
| 177 | if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) || |
| 178 | !write_ok_or_segv(regs->si, sizeof(struct timezone))) { |
| 179 | ret = -EFAULT; |
| 180 | goto check_fault; |
| 181 | } |
| 182 | |
| 183 | syscall_nr = __NR_gettimeofday; |
| 184 | break; |
| 185 | |
| 186 | case 1: |
| 187 | if (!write_ok_or_segv(regs->di, sizeof(time_t))) { |
| 188 | ret = -EFAULT; |
| 189 | goto check_fault; |
| 190 | } |
| 191 | |
| 192 | syscall_nr = __NR_time; |
| 193 | break; |
| 194 | |
| 195 | case 2: |
| 196 | if (!write_ok_or_segv(regs->di, sizeof(unsigned)) || |
| 197 | !write_ok_or_segv(regs->si, sizeof(unsigned))) { |
| 198 | ret = -EFAULT; |
| 199 | goto check_fault; |
| 200 | } |
| 201 | |
| 202 | syscall_nr = __NR_getcpu; |
| 203 | break; |
| 204 | } |
| 205 | |
| 206 | /* |
| 207 | * Handle seccomp. regs->ip must be the original value. |
| 208 | * See seccomp_send_sigsys and Documentation/prctl/seccomp_filter.txt. |
| 209 | * |
| 210 | * We could optimize the seccomp disabled case, but performance |
| 211 | * here doesn't matter. |
| 212 | */ |
| 213 | regs->orig_ax = syscall_nr; |
| 214 | regs->ax = -ENOSYS; |
Andy Lutomirski | 2f275de | 2016-05-27 12:57:02 -0700 | [diff] [blame] | 215 | tmp = secure_computing(NULL); |
Andy Lutomirski | 87b526d | 2012-10-01 11:40:45 -0700 | [diff] [blame] | 216 | if ((!tmp && regs->orig_ax != syscall_nr) || regs->ip != address) { |
| 217 | warn_bad_vsyscall(KERN_DEBUG, regs, |
| 218 | "seccomp tried to change syscall nr or ip"); |
| 219 | do_exit(SIGSYS); |
| 220 | } |
Andy Lutomirski | 2689310 | 2014-11-04 15:36:50 -0800 | [diff] [blame] | 221 | regs->orig_ax = -1; |
Andy Lutomirski | 87b526d | 2012-10-01 11:40:45 -0700 | [diff] [blame] | 222 | if (tmp) |
| 223 | goto do_ret; /* skip requested */ |
| 224 | |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 225 | /* |
| 226 | * With a real vsyscall, page faults cause SIGSEGV. We want to |
| 227 | * preserve that behavior to make writing exploits harder. |
| 228 | */ |
Ingo Molnar | 2a53ccb | 2016-07-15 10:21:11 +0200 | [diff] [blame] | 229 | prev_sig_on_uaccess_err = current->thread.sig_on_uaccess_err; |
| 230 | current->thread.sig_on_uaccess_err = 1; |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 231 | |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 232 | ret = -EFAULT; |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 233 | switch (vsyscall_nr) { |
| 234 | case 0: |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 235 | ret = sys_gettimeofday( |
| 236 | (struct timeval __user *)regs->di, |
| 237 | (struct timezone __user *)regs->si); |
| 238 | break; |
| 239 | |
| 240 | case 1: |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 241 | ret = sys_time((time_t __user *)regs->di); |
| 242 | break; |
| 243 | |
| 244 | case 2: |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 245 | ret = sys_getcpu((unsigned __user *)regs->di, |
| 246 | (unsigned __user *)regs->si, |
Emil Goode | 46ed99d | 2012-04-01 20:48:04 +0200 | [diff] [blame] | 247 | NULL); |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 248 | break; |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 249 | } |
| 250 | |
Ingo Molnar | 2a53ccb | 2016-07-15 10:21:11 +0200 | [diff] [blame] | 251 | current->thread.sig_on_uaccess_err = prev_sig_on_uaccess_err; |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 252 | |
Andy Lutomirski | 87b526d | 2012-10-01 11:40:45 -0700 | [diff] [blame] | 253 | check_fault: |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 254 | if (ret == -EFAULT) { |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 255 | /* Bad news -- userspace fed a bad pointer to a vsyscall. */ |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 256 | warn_bad_vsyscall(KERN_INFO, regs, |
| 257 | "vsyscall fault (exploit attempt?)"); |
Andy Lutomirski | 4fc3490 | 2011-11-07 16:33:40 -0800 | [diff] [blame] | 258 | |
| 259 | /* |
| 260 | * If we failed to generate a signal for any reason, |
| 261 | * generate one here. (This should be impossible.) |
| 262 | */ |
| 263 | if (WARN_ON_ONCE(!sigismember(&tsk->pending.signal, SIGBUS) && |
| 264 | !sigismember(&tsk->pending.signal, SIGSEGV))) |
| 265 | goto sigsegv; |
| 266 | |
| 267 | return true; /* Don't emulate the ret. */ |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 268 | } |
| 269 | |
| 270 | regs->ax = ret; |
| 271 | |
Will Drewry | 5651721 | 2012-07-13 12:06:35 -0500 | [diff] [blame] | 272 | do_ret: |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 273 | /* Emulate a ret instruction. */ |
| 274 | regs->ip = caller; |
| 275 | regs->sp += 8; |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 276 | return true; |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 277 | |
| 278 | sigsegv: |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 279 | force_sig(SIGSEGV, current); |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 280 | return true; |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 281 | } |
| 282 | |
| 283 | /* |
Andy Lutomirski | b935909 | 2014-09-23 10:50:51 -0700 | [diff] [blame] | 284 | * A pseudo VMA to allow ptrace access for the vsyscall page. This only |
| 285 | * covers the 64bit vsyscall page now. 32bit has a real VMA now and does |
| 286 | * not need special handling anymore: |
| 287 | */ |
| 288 | static const char *gate_vma_name(struct vm_area_struct *vma) |
| 289 | { |
| 290 | return "[vsyscall]"; |
| 291 | } |
Kirill A. Shutemov | 7cbea8d | 2015-09-09 15:39:26 -0700 | [diff] [blame] | 292 | static const struct vm_operations_struct gate_vma_ops = { |
Andy Lutomirski | b935909 | 2014-09-23 10:50:51 -0700 | [diff] [blame] | 293 | .name = gate_vma_name, |
| 294 | }; |
| 295 | static struct vm_area_struct gate_vma = { |
| 296 | .vm_start = VSYSCALL_ADDR, |
| 297 | .vm_end = VSYSCALL_ADDR + PAGE_SIZE, |
| 298 | .vm_page_prot = PAGE_READONLY_EXEC, |
| 299 | .vm_flags = VM_READ | VM_EXEC, |
| 300 | .vm_ops = &gate_vma_ops, |
| 301 | }; |
| 302 | |
| 303 | struct vm_area_struct *get_gate_vma(struct mm_struct *mm) |
| 304 | { |
Brian Gerst | c338867 | 2015-06-22 07:55:16 -0400 | [diff] [blame] | 305 | #ifdef CONFIG_COMPAT |
Andy Lutomirski | b935909 | 2014-09-23 10:50:51 -0700 | [diff] [blame] | 306 | if (!mm || mm->context.ia32_compat) |
| 307 | return NULL; |
| 308 | #endif |
Andy Lutomirski | 87983c6 | 2014-10-29 14:33:45 -0700 | [diff] [blame] | 309 | if (vsyscall_mode == NONE) |
| 310 | return NULL; |
Andy Lutomirski | b935909 | 2014-09-23 10:50:51 -0700 | [diff] [blame] | 311 | return &gate_vma; |
| 312 | } |
| 313 | |
| 314 | int in_gate_area(struct mm_struct *mm, unsigned long addr) |
| 315 | { |
| 316 | struct vm_area_struct *vma = get_gate_vma(mm); |
| 317 | |
| 318 | if (!vma) |
| 319 | return 0; |
| 320 | |
| 321 | return (addr >= vma->vm_start) && (addr < vma->vm_end); |
| 322 | } |
| 323 | |
| 324 | /* |
| 325 | * Use this when you have no reliable mm, typically from interrupt |
| 326 | * context. It is less reliable than using a task's mm and may give |
| 327 | * false positives. |
| 328 | */ |
| 329 | int in_gate_area_no_mm(unsigned long addr) |
| 330 | { |
Andy Lutomirski | 87983c6 | 2014-10-29 14:33:45 -0700 | [diff] [blame] | 331 | return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR; |
Andy Lutomirski | b935909 | 2014-09-23 10:50:51 -0700 | [diff] [blame] | 332 | } |
| 333 | |
Ingo Molnar | e402644 | 2008-01-30 13:32:39 +0100 | [diff] [blame] | 334 | void __init map_vsyscall(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | { |
Andy Lutomirski | 3ae3665 | 2011-08-10 11:15:32 -0400 | [diff] [blame] | 336 | extern char __vsyscall_page; |
| 337 | unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | |
Andy Lutomirski | 87983c6 | 2014-10-29 14:33:45 -0700 | [diff] [blame] | 339 | if (vsyscall_mode != NONE) |
| 340 | __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall, |
| 341 | vsyscall_mode == NATIVE |
| 342 | ? PAGE_KERNEL_VSYSCALL |
| 343 | : PAGE_KERNEL_VVAR); |
| 344 | |
Andy Lutomirski | f40c330 | 2014-05-05 12:19:36 -0700 | [diff] [blame] | 345 | BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) != |
| 346 | (unsigned long)VSYSCALL_ADDR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | } |