arch/arm64/kernel/armv8_deprecated.c

   1 /*
   2  *  Copyright (C) 2014 ARM Limited
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/cpu.h>
  10 #include <linux/init.h>
  11 #include <linux/list.h>
  12 #include <linux/perf_event.h>
  13 #include <linux/sched.h>
  14 #include <linux/slab.h>
  15 #include <linux/sysctl.h>
  16
  17 #include <asm/cpufeature.h>
  18 #include <asm/insn.h>
  19 #include <asm/sysreg.h>
  20 #include <asm/system_misc.h>
  21 #include <asm/traps.h>
  22 #include <asm/uaccess.h>
  23 #include <asm/cpufeature.h>
  24
  25 #define CREATE_TRACE_POINTS
  26 #include "trace-events-emulation.h"
  27
  28 /*
  29  * The runtime support for deprecated instruction support can be in one of
  30  * following three states -
  31  *
  32  * 0 = undef
  33  * 1 = emulate (software emulation)
  34  * 2 = hw (supported in hardware)
  35  */
  36 enum insn_emulation_mode {
  37         INSN_UNDEF,
  38         INSN_EMULATE,
  39         INSN_HW,
  40 };
  41
  42 enum legacy_insn_status {
  43         INSN_DEPRECATED,
  44         INSN_OBSOLETE,
  45 };
  46
  47 struct insn_emulation_ops {
  48         const char              *name;
  49         enum legacy_insn_status status;
  50         struct undef_hook       *hooks;
  51         int                     (*set_hw_mode)(bool enable);
  52 };
  53
  54 struct insn_emulation {
  55         struct list_head node;
  56         struct insn_emulation_ops *ops;
  57         int current_mode;
  58         int min;
  59         int max;
  60 };
  61
  62 static LIST_HEAD(insn_emulation);
  63 static int nr_insn_emulated __initdata;
  64 static DEFINE_RAW_SPINLOCK(insn_emulation_lock);
  65
  66 static void register_emulation_hooks(struct insn_emulation_ops *ops)
  67 {
  68         struct undef_hook *hook;
  69
  70         BUG_ON(!ops->hooks);
  71
  72         for (hook = ops->hooks; hook->instr_mask; hook++)
  73                 register_undef_hook(hook);
  74
  75         pr_notice("Registered %s emulation handler\n", ops->name);
  76 }
  77
  78 static void remove_emulation_hooks(struct insn_emulation_ops *ops)
  79 {
  80         struct undef_hook *hook;
  81
  82         BUG_ON(!ops->hooks);
  83
  84         for (hook = ops->hooks; hook->instr_mask; hook++)
  85                 unregister_undef_hook(hook);
  86
  87         pr_notice("Removed %s emulation handler\n", ops->name);
  88 }
  89
  90 static void enable_insn_hw_mode(void *data)
  91 {
  92         struct insn_emulation *insn = (struct insn_emulation *)data;
  93         if (insn->ops->set_hw_mode)
  94                 insn->ops->set_hw_mode(true);
  95 }
  96
  97 static void disable_insn_hw_mode(void *data)
  98 {
  99         struct insn_emulation *insn = (struct insn_emulation *)data;
 100         if (insn->ops->set_hw_mode)
 101                 insn->ops->set_hw_mode(false);
 102 }
 103
 104 /* Run set_hw_mode(mode) on all active CPUs */
 105 static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable)
 106 {
 107         if (!insn->ops->set_hw_mode)
 108                 return -EINVAL;
 109         if (enable)
 110                 on_each_cpu(enable_insn_hw_mode, (void *)insn, true);
 111         else
 112                 on_each_cpu(disable_insn_hw_mode, (void *)insn, true);
 113         return 0;
 114 }
 115
 116 /*
 117  * Run set_hw_mode for all insns on a starting CPU.
 118  * Returns:
 119  *  0           - If all the hooks ran successfully.
 120  * -EINVAL      - At least one hook is not supported by the CPU.
 121  */
 122 static int run_all_insn_set_hw_mode(unsigned int cpu)
 123 {
 124         int rc = 0;
 125         unsigned long flags;
 126         struct insn_emulation *insn;
 127
 128         raw_spin_lock_irqsave(&insn_emulation_lock, flags);
 129         list_for_each_entry(insn, &insn_emulation, node) {
 130                 bool enable = (insn->current_mode == INSN_HW);
 131                 if (insn->ops->set_hw_mode && insn->ops->set_hw_mode(enable)) {
 132                         pr_warn("CPU[%u] cannot support the emulation of %s",
 133                                 cpu, insn->ops->name);
 134                         rc = -EINVAL;
 135                 }
 136         }
 137         raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
 138         return rc;
 139 }
 140
 141 static int update_insn_emulation_mode(struct insn_emulation *insn,
 142                                        enum insn_emulation_mode prev)
 143 {
 144         int ret = 0;
 145
 146         switch (prev) {
 147         case INSN_UNDEF: /* Nothing to be done */
 148                 break;
 149         case INSN_EMULATE:
 150                 remove_emulation_hooks(insn->ops);
 151                 break;
 152         case INSN_HW:
 153                 if (!run_all_cpu_set_hw_mode(insn, false))
 154                         pr_notice("Disabled %s support\n", insn->ops->name);
 155                 break;
 156         }
 157
 158         switch (insn->current_mode) {
 159         case INSN_UNDEF:
 160                 break;
 161         case INSN_EMULATE:
 162                 register_emulation_hooks(insn->ops);
 163                 break;
 164         case INSN_HW:
 165                 ret = run_all_cpu_set_hw_mode(insn, true);
 166                 if (!ret)
 167                         pr_notice("Enabled %s support\n", insn->ops->name);
 168                 break;
 169         }
 170
 171         return ret;
 172 }
 173
 174 static void __init register_insn_emulation(struct insn_emulation_ops *ops)
 175 {
 176         unsigned long flags;
 177         struct insn_emulation *insn;
 178
 179         insn = kzalloc(sizeof(*insn), GFP_KERNEL);
 180         insn->ops = ops;
 181         insn->min = INSN_UNDEF;
 182
 183         switch (ops->status) {
 184         case INSN_DEPRECATED:
 185                 insn->current_mode = INSN_EMULATE;
 186                 /* Disable the HW mode if it was turned on at early boot time */
 187                 run_all_cpu_set_hw_mode(insn, false);
 188                 insn->max = INSN_HW;
 189                 break;
 190         case INSN_OBSOLETE:
 191                 insn->current_mode = INSN_UNDEF;
 192                 insn->max = INSN_EMULATE;
 193                 break;
 194         }
 195
 196         raw_spin_lock_irqsave(&insn_emulation_lock, flags);
 197         list_add(&insn->node, &insn_emulation);
 198         nr_insn_emulated++;
 199         raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
 200
 201         /* Register any handlers if required */
 202         update_insn_emulation_mode(insn, INSN_UNDEF);
 203 }
 204
 205 static int emulation_proc_handler(struct ctl_table *table, int write,
 206                                   void __user *buffer, size_t *lenp,
 207                                   loff_t *ppos)
 208 {
 209         int ret = 0;
 210         struct insn_emulation *insn = (struct insn_emulation *) table->data;
 211         enum insn_emulation_mode prev_mode = insn->current_mode;
 212
 213         table->data = &insn->current_mode;
 214         ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 215
 216         if (ret || !write || prev_mode == insn->current_mode)
 217                 goto ret;
 218
 219         ret = update_insn_emulation_mode(insn, prev_mode);
 220         if (ret) {
 221                 /* Mode change failed, revert to previous mode. */
 222                 insn->current_mode = prev_mode;
 223                 update_insn_emulation_mode(insn, INSN_UNDEF);
 224         }
 225 ret:
 226         table->data = insn;
 227         return ret;
 228 }
 229
 230 static struct ctl_table ctl_abi[] = {
 231         {
 232                 .procname = "abi",
 233                 .mode = 0555,
 234         },
 235         { }
 236 };
 237
 238 static void __init register_insn_emulation_sysctl(struct ctl_table *table)
 239 {
 240         unsigned long flags;
 241         int i = 0;
 242         struct insn_emulation *insn;
 243         struct ctl_table *insns_sysctl, *sysctl;
 244
 245         insns_sysctl = kzalloc(sizeof(*sysctl) * (nr_insn_emulated + 1),
 246                               GFP_KERNEL);
 247
 248         raw_spin_lock_irqsave(&insn_emulation_lock, flags);
 249         list_for_each_entry(insn, &insn_emulation, node) {
 250                 sysctl = &insns_sysctl[i];
 251
 252                 sysctl->mode = 0644;
 253                 sysctl->maxlen = sizeof(int);
 254
 255                 sysctl->procname = insn->ops->name;
 256                 sysctl->data = insn;
 257                 sysctl->extra1 = &insn->min;
 258                 sysctl->extra2 = &insn->max;
 259                 sysctl->proc_handler = emulation_proc_handler;
 260                 i++;
 261         }
 262         raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
 263
 264         table->child = insns_sysctl;
 265         register_sysctl_table(table);
 266 }
 267
 268 /*
 269  *  Implement emulation of the SWP/SWPB instructions using load-exclusive and
 270  *  store-exclusive.
 271  *
 272  *  Syntax of SWP{B} instruction: SWP{B}<c> <Rt>, <Rt2>, [<Rn>]
 273  *  Where: Rt  = destination
 274  *         Rt2 = source
 275  *         Rn  = address
 276  */
 277
 278 /*
 279  * Error-checking SWP macros implemented using ldxr{b}/stxr{b}
 280  */
 281
 282 /* Arbitrary constant to ensure forward-progress of the LL/SC loop */
 283 #define __SWP_LL_SC_LOOPS       4
 284
 285 #define __user_swpX_asm(data, addr, res, temp, temp2, B)        \
 286 do {                                                            \
 287         uaccess_enable();                                       \
 288         __asm__ __volatile__(                                   \
 289         "       mov             %w3, %w7\n"                     \
 290         "0:     ldxr"B"         %w2, [%4]\n"                    \
 291         "1:     stxr"B"         %w0, %w1, [%4]\n"               \
 292         "       cbz             %w0, 2f\n"                      \
 293         "       sub             %w3, %w3, #1\n"                 \
 294         "       cbnz            %w3, 0b\n"                      \
 295         "       mov             %w0, %w5\n"                     \
 296         "       b               3f\n"                           \
 297         "2:\n"                                                  \
 298         "       mov             %w1, %w2\n"                     \
 299         "3:\n"                                                  \
 300         "       .pushsection     .fixup,\"ax\"\n"               \
 301         "       .align          2\n"                            \
 302         "4:     mov             %w0, %w6\n"                     \
 303         "       b               3b\n"                           \
 304         "       .popsection"                                    \
 305         _ASM_EXTABLE(0b, 4b)                                    \
 306         _ASM_EXTABLE(1b, 4b)                                    \
 307         : "=&r" (res), "+r" (data), "=&r" (temp), "=&r" (temp2) \
 308         : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT),             \
 309           "i" (__SWP_LL_SC_LOOPS)                               \
 310         : "memory");                                            \
 311         uaccess_disable();                                      \
 312 } while (0)
 313
 314 #define __user_swp_asm(data, addr, res, temp, temp2) \
 315         __user_swpX_asm(data, addr, res, temp, temp2, "")
 316 #define __user_swpb_asm(data, addr, res, temp, temp2) \
 317         __user_swpX_asm(data, addr, res, temp, temp2, "b")
 318
 319 /*
 320  * Bit 22 of the instruction encoding distinguishes between
 321  * the SWP and SWPB variants (bit set means SWPB).
 322  */
 323 #define TYPE_SWPB (1 << 22)
 324
 325 static int emulate_swpX(unsigned int address, unsigned int *data,
 326                         unsigned int type)
 327 {
 328         unsigned int res = 0;
 329
 330         if ((type != TYPE_SWPB) && (address & 0x3)) {
 331                 /* SWP to unaligned address not permitted */
 332                 pr_debug("SWP instruction on unaligned pointer!\n");
 333                 return -EFAULT;
 334         }
 335
 336         while (1) {
 337                 unsigned long temp, temp2;
 338
 339                 if (type == TYPE_SWPB)
 340                         __user_swpb_asm(*data, address, res, temp, temp2);
 341                 else
 342                         __user_swp_asm(*data, address, res, temp, temp2);
 343
 344                 if (likely(res != -EAGAIN) || signal_pending(current))
 345                         break;
 346
 347                 cond_resched();
 348         }
 349
 350         return res;
 351 }
 352
 353 #define ARM_OPCODE_CONDTEST_FAIL   0
 354 #define ARM_OPCODE_CONDTEST_PASS   1
 355 #define ARM_OPCODE_CONDTEST_UNCOND 2
 356
 357 #define ARM_OPCODE_CONDITION_UNCOND     0xf
 358
 359 static unsigned int __kprobes aarch32_check_condition(u32 opcode, u32 psr)
 360 {
 361         u32 cc_bits  = opcode >> 28;
 362
 363         if (cc_bits != ARM_OPCODE_CONDITION_UNCOND) {
 364                 if ((*aarch32_opcode_cond_checks[cc_bits])(psr))
 365                         return ARM_OPCODE_CONDTEST_PASS;
 366                 else
 367                         return ARM_OPCODE_CONDTEST_FAIL;
 368         }
 369         return ARM_OPCODE_CONDTEST_UNCOND;
 370 }
 371
 372 /*
 373  * swp_handler logs the id of calling process, dissects the instruction, sanity
 374  * checks the memory location, calls emulate_swpX for the actual operation and
 375  * deals with fixup/error handling before returning
 376  */
 377 static int swp_handler(struct pt_regs *regs, u32 instr)
 378 {
 379         u32 destreg, data, type, address = 0;
 380         int rn, rt2, res = 0;
 381
 382         perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
 383
 384         type = instr & TYPE_SWPB;
 385
 386         switch (aarch32_check_condition(instr, regs->pstate)) {
 387         case ARM_OPCODE_CONDTEST_PASS:
 388                 break;
 389         case ARM_OPCODE_CONDTEST_FAIL:
 390                 /* Condition failed - return to next instruction */
 391                 goto ret;
 392         case ARM_OPCODE_CONDTEST_UNCOND:
 393                 /* If unconditional encoding - not a SWP, undef */
 394                 return -EFAULT;
 395         default:
 396                 return -EINVAL;
 397         }
 398
 399         rn = aarch32_insn_extract_reg_num(instr, A32_RN_OFFSET);
 400         rt2 = aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET);
 401
 402         address = (u32)regs->user_regs.regs[rn];
 403         data    = (u32)regs->user_regs.regs[rt2];
 404         destreg = aarch32_insn_extract_reg_num(instr, A32_RT_OFFSET);
 405
 406         pr_debug("addr in r%d->0x%08x, dest is r%d, source in r%d->0x%08x)\n",
 407                 rn, address, destreg,
 408                 aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET), data);
 409
 410         /* Check access in reasonable access range for both SWP and SWPB */
 411         if (!access_ok(VERIFY_WRITE, (address & ~3), 4)) {
 412                 pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n",
 413                         address);
 414                 goto fault;
 415         }
 416
 417         res = emulate_swpX(address, &data, type);
 418         if (res == -EFAULT)
 419                 goto fault;
 420         else if (res == 0)
 421                 regs->user_regs.regs[destreg] = data;
 422
 423 ret:
 424         if (type == TYPE_SWPB)
 425                 trace_instruction_emulation("swpb", regs->pc);
 426         else
 427                 trace_instruction_emulation("swp", regs->pc);
 428
 429         pr_warn_ratelimited("\"%s\" (%ld) uses obsolete SWP{B} instruction at 0x%llx\n",
 430                         current->comm, (unsigned long)current->pid, regs->pc);
 431
 432         regs->pc += 4;
 433         return 0;
 434
 435 fault:
 436         pr_debug("SWP{B} emulation: access caused memory abort!\n");
 437         arm64_notify_segfault(regs, address);
 438
 439         return 0;
 440 }
 441
 442 /*
 443  * Only emulate SWP/SWPB executed in ARM state/User mode.
 444  * The kernel must be SWP free and SWP{B} does not exist in Thumb.
 445  */
 446 static struct undef_hook swp_hooks[] = {
 447         {
 448                 .instr_mask     = 0x0fb00ff0,
 449                 .instr_val      = 0x01000090,
 450                 .pstate_mask    = COMPAT_PSR_MODE_MASK,
 451                 .pstate_val     = COMPAT_PSR_MODE_USR,
 452                 .fn             = swp_handler
 453         },
 454         { }
 455 };
 456
 457 static struct insn_emulation_ops swp_ops = {
 458         .name = "swp",
 459         .status = INSN_OBSOLETE,
 460         .hooks = swp_hooks,
 461         .set_hw_mode = NULL,
 462 };
 463
 464 static int cp15barrier_handler(struct pt_regs *regs, u32 instr)
 465 {
 466         perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
 467
 468         switch (aarch32_check_condition(instr, regs->pstate)) {
 469         case ARM_OPCODE_CONDTEST_PASS:
 470                 break;
 471         case ARM_OPCODE_CONDTEST_FAIL:
 472                 /* Condition failed - return to next instruction */
 473                 goto ret;
 474         case ARM_OPCODE_CONDTEST_UNCOND:
 475                 /* If unconditional encoding - not a barrier instruction */
 476                 return -EFAULT;
 477         default:
 478                 return -EINVAL;
 479         }
 480
 481         switch (aarch32_insn_mcr_extract_crm(instr)) {
 482         case 10:
 483                 /*
 484                  * dmb - mcr p15, 0, Rt, c7, c10, 5
 485                  * dsb - mcr p15, 0, Rt, c7, c10, 4
 486                  */
 487                 if (aarch32_insn_mcr_extract_opc2(instr) == 5) {
 488                         dmb(sy);
 489                         trace_instruction_emulation(
 490                                 "mcr p15, 0, Rt, c7, c10, 5 ; dmb", regs->pc);
 491                 } else {
 492                         dsb(sy);
 493                         trace_instruction_emulation(
 494                                 "mcr p15, 0, Rt, c7, c10, 4 ; dsb", regs->pc);
 495                 }
 496                 break;
 497         case 5:
 498                 /*
 499                  * isb - mcr p15, 0, Rt, c7, c5, 4
 500                  *
 501                  * Taking an exception or returning from one acts as an
 502                  * instruction barrier. So no explicit barrier needed here.
 503                  */
 504                 trace_instruction_emulation(
 505                         "mcr p15, 0, Rt, c7, c5, 4 ; isb", regs->pc);
 506                 break;
 507         }
 508
 509 ret:
 510         pr_warn_ratelimited("\"%s\" (%ld) uses deprecated CP15 Barrier instruction at 0x%llx\n",
 511                         current->comm, (unsigned long)current->pid, regs->pc);
 512
 513         regs->pc += 4;
 514         return 0;
 515 }
 516
 517 static int cp15_barrier_set_hw_mode(bool enable)
 518 {
 519         if (enable)
 520                 config_sctlr_el1(0, SCTLR_EL1_CP15BEN);
 521         else
 522                 config_sctlr_el1(SCTLR_EL1_CP15BEN, 0);
 523         return 0;
 524 }
 525
 526 static struct undef_hook cp15_barrier_hooks[] = {
 527         {
 528                 .instr_mask     = 0x0fff0fdf,
 529                 .instr_val      = 0x0e070f9a,
 530                 .pstate_mask    = COMPAT_PSR_MODE_MASK,
 531                 .pstate_val     = COMPAT_PSR_MODE_USR,
 532                 .fn             = cp15barrier_handler,
 533         },
 534         {
 535                 .instr_mask     = 0x0fff0fff,
 536                 .instr_val      = 0x0e070f95,
 537                 .pstate_mask    = COMPAT_PSR_MODE_MASK,
 538                 .pstate_val     = COMPAT_PSR_MODE_USR,
 539                 .fn             = cp15barrier_handler,
 540         },
 541         { }
 542 };
 543
 544 static struct insn_emulation_ops cp15_barrier_ops = {
 545         .name = "cp15_barrier",
 546         .status = INSN_DEPRECATED,
 547         .hooks = cp15_barrier_hooks,
 548         .set_hw_mode = cp15_barrier_set_hw_mode,
 549 };
 550
 551 static int setend_set_hw_mode(bool enable)
 552 {
 553         if (!cpu_supports_mixed_endian_el0())
 554                 return -EINVAL;
 555
 556         if (enable)
 557                 config_sctlr_el1(SCTLR_EL1_SED, 0);
 558         else
 559                 config_sctlr_el1(0, SCTLR_EL1_SED);
 560         return 0;
 561 }
 562
 563 static int compat_setend_handler(struct pt_regs *regs, u32 big_endian)
 564 {
 565         char *insn;
 566
 567         perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
 568
 569         if (big_endian) {
 570                 insn = "setend be";
 571                 regs->pstate |= COMPAT_PSR_E_BIT;
 572         } else {
 573                 insn = "setend le";
 574                 regs->pstate &= ~COMPAT_PSR_E_BIT;
 575         }
 576
 577         trace_instruction_emulation(insn, regs->pc);
 578         pr_warn_ratelimited("\"%s\" (%ld) uses deprecated setend instruction at 0x%llx\n",
 579                         current->comm, (unsigned long)current->pid, regs->pc);
 580
 581         return 0;
 582 }
 583
 584 static int a32_setend_handler(struct pt_regs *regs, u32 instr)
 585 {
 586         int rc = compat_setend_handler(regs, (instr >> 9) & 1);
 587         regs->pc += 4;
 588         return rc;
 589 }
 590
 591 static int t16_setend_handler(struct pt_regs *regs, u32 instr)
 592 {
 593         int rc = compat_setend_handler(regs, (instr >> 3) & 1);
 594         regs->pc += 2;
 595         return rc;
 596 }
 597
 598 static struct undef_hook setend_hooks[] = {
 599         {
 600                 .instr_mask     = 0xfffffdff,
 601                 .instr_val      = 0xf1010000,
 602                 .pstate_mask    = COMPAT_PSR_MODE_MASK,
 603                 .pstate_val     = COMPAT_PSR_MODE_USR,
 604                 .fn             = a32_setend_handler,
 605         },
 606         {
 607                 /* Thumb mode */
 608                 .instr_mask     = 0x0000fff7,
 609                 .instr_val      = 0x0000b650,
 610                 .pstate_mask    = (COMPAT_PSR_T_BIT | COMPAT_PSR_MODE_MASK),
 611                 .pstate_val     = (COMPAT_PSR_T_BIT | COMPAT_PSR_MODE_USR),
 612                 .fn             = t16_setend_handler,
 613         },
 614         {}
 615 };
 616
 617 static struct insn_emulation_ops setend_ops = {
 618         .name = "setend",
 619         .status = INSN_DEPRECATED,
 620         .hooks = setend_hooks,
 621         .set_hw_mode = setend_set_hw_mode,
 622 };
 623
 624 /*
 625  * Invoked as late_initcall, since not needed before init spawned.
 626  */
 627 static int __init armv8_deprecated_init(void)
 628 {
 629         if (IS_ENABLED(CONFIG_SWP_EMULATION))
 630                 register_insn_emulation(&swp_ops);
 631
 632         if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION))
 633                 register_insn_emulation(&cp15_barrier_ops);
 634
 635         if (IS_ENABLED(CONFIG_SETEND_EMULATION)) {
 636                 if(system_supports_mixed_endian_el0())
 637                         register_insn_emulation(&setend_ops);
 638                 else
 639                         pr_info("setend instruction emulation is not supported on the system");
 640         }
 641
 642         cpuhp_setup_state_nocalls(CPUHP_AP_ARM64_ISNDEP_STARTING,
 643                                   "AP_ARM64_ISNDEP_STARTING",
 644                                   run_all_insn_set_hw_mode, NULL);
 645         register_insn_emulation_sysctl(ctl_abi);
 646
 647         return 0;
 648 }
 649
 650 late_initcall(armv8_deprecated_init);