arch/mips/kernel/process.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
   7  * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
   8  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   9  * Copyright (C) 2004 Thiemo Seufer
  10  * Copyright (C) 2013  Imagination Technologies Ltd.
  11  */
  12 #include <linux/errno.h>
  13 #include <linux/sched.h>
  14 #include <linux/tick.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/stddef.h>
  18 #include <linux/unistd.h>
  19 #include <linux/export.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/mman.h>
  22 #include <linux/personality.h>
  23 #include <linux/sys.h>
  24 #include <linux/init.h>
  25 #include <linux/completion.h>
  26 #include <linux/kallsyms.h>
  27 #include <linux/random.h>
  28 #include <linux/prctl.h>
  29
  30 #include <asm/asm.h>
  31 #include <asm/bootinfo.h>
  32 #include <asm/cpu.h>
  33 #include <asm/dsemul.h>
  34 #include <asm/dsp.h>
  35 #include <asm/fpu.h>
  36 #include <asm/msa.h>
  37 #include <asm/pgtable.h>
  38 #include <asm/mipsregs.h>
  39 #include <asm/processor.h>
  40 #include <asm/reg.h>
  41 #include <asm/uaccess.h>
  42 #include <asm/io.h>
  43 #include <asm/elf.h>
  44 #include <asm/isadep.h>
  45 #include <asm/inst.h>
  46 #include <asm/stacktrace.h>
  47 #include <asm/irq_regs.h>
  48
  49 #ifdef CONFIG_HOTPLUG_CPU
  50 void arch_cpu_idle_dead(void)
  51 {
  52         /* What the heck is this check doing ? */
  53         if (!cpumask_test_cpu(smp_processor_id(), &cpu_callin_map))
  54                 play_dead();
  55 }
  56 #endif
  57
  58 asmlinkage void ret_from_fork(void);
  59 asmlinkage void ret_from_kernel_thread(void);
  60
  61 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
  62 {
  63         unsigned long status;
  64
  65         /* New thread loses kernel privileges. */
  66         status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
  67         status |= KU_USER;
  68         regs->cp0_status = status;
  69         lose_fpu(0);
  70         clear_thread_flag(TIF_MSA_CTX_LIVE);
  71         clear_used_math();
  72         atomic_set(&current->thread.bd_emu_frame, BD_EMUFRAME_NONE);
  73         init_dsp();
  74         regs->cp0_epc = pc;
  75         regs->regs[29] = sp;
  76 }
  77
  78 void exit_thread(struct task_struct *tsk)
  79 {
  80         /*
  81          * User threads may have allocated a delay slot emulation frame.
  82          * If so, clean up that allocation.
  83          */
  84         if (!(current->flags & PF_KTHREAD))
  85                 dsemul_thread_cleanup(tsk);
  86 }
  87
  88 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
  89 {
  90         /*
  91          * Save any process state which is live in hardware registers to the
  92          * parent context prior to duplication. This prevents the new child
  93          * state becoming stale if the parent is preempted before copy_thread()
  94          * gets a chance to save the parent's live hardware registers to the
  95          * child context.
  96          */
  97         preempt_disable();
  98
  99         if (is_msa_enabled())
 100                 save_msa(current);
 101         else if (is_fpu_owner())
 102                 _save_fp(current);
 103
 104         save_dsp(current);
 105
 106         preempt_enable();
 107
 108         *dst = *src;
 109         return 0;
 110 }
 111
 112 /*
 113  * Copy architecture-specific thread state
 114  */
 115 int copy_thread(unsigned long clone_flags, unsigned long usp,
 116         unsigned long kthread_arg, struct task_struct *p)
 117 {
 118         struct thread_info *ti = task_thread_info(p);
 119         struct pt_regs *childregs, *regs = current_pt_regs();
 120         unsigned long childksp;
 121         p->set_child_tid = p->clear_child_tid = NULL;
 122
 123         childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
 124
 125         /* set up new TSS. */
 126         childregs = (struct pt_regs *) childksp - 1;
 127         /*  Put the stack after the struct pt_regs.  */
 128         childksp = (unsigned long) childregs;
 129         p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
 130         if (unlikely(p->flags & PF_KTHREAD)) {
 131                 /* kernel thread */
 132                 unsigned long status = p->thread.cp0_status;
 133                 memset(childregs, 0, sizeof(struct pt_regs));
 134                 ti->addr_limit = KERNEL_DS;
 135                 p->thread.reg16 = usp; /* fn */
 136                 p->thread.reg17 = kthread_arg;
 137                 p->thread.reg29 = childksp;
 138                 p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
 139 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 140                 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
 141                          ((status & (ST0_KUC | ST0_IEC)) << 2);
 142 #else
 143                 status |= ST0_EXL;
 144 #endif
 145                 childregs->cp0_status = status;
 146                 return 0;
 147         }
 148
 149         /* user thread */
 150         *childregs = *regs;
 151         childregs->regs[7] = 0; /* Clear error flag */
 152         childregs->regs[2] = 0; /* Child gets zero as return value */
 153         if (usp)
 154                 childregs->regs[29] = usp;
 155         ti->addr_limit = USER_DS;
 156
 157         p->thread.reg29 = (unsigned long) childregs;
 158         p->thread.reg31 = (unsigned long) ret_from_fork;
 159
 160         /*
 161          * New tasks lose permission to use the fpu. This accelerates context
 162          * switching for most programs since they don't use the fpu.
 163          */
 164         childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
 165
 166         clear_tsk_thread_flag(p, TIF_USEDFPU);
 167         clear_tsk_thread_flag(p, TIF_USEDMSA);
 168         clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
 169
 170 #ifdef CONFIG_MIPS_MT_FPAFF
 171         clear_tsk_thread_flag(p, TIF_FPUBOUND);
 172 #endif /* CONFIG_MIPS_MT_FPAFF */
 173
 174         atomic_set(&p->thread.bd_emu_frame, BD_EMUFRAME_NONE);
 175
 176         if (clone_flags & CLONE_SETTLS)
 177                 ti->tp_value = regs->regs[7];
 178
 179         return 0;
 180 }
 181
 182 #ifdef CONFIG_CC_STACKPROTECTOR
 183 #include <linux/stackprotector.h>
 184 unsigned long __stack_chk_guard __read_mostly;
 185 EXPORT_SYMBOL(__stack_chk_guard);
 186 #endif
 187
 188 struct mips_frame_info {
 189         void            *func;
 190         unsigned long   func_size;
 191         int             frame_size;
 192         int             pc_offset;
 193 };
 194
 195 #define J_TARGET(pc,target)     \
 196                 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
 197
 198 static inline int is_ra_save_ins(union mips_instruction *ip)
 199 {
 200 #ifdef CONFIG_CPU_MICROMIPS
 201         union mips_instruction mmi;
 202
 203         /*
 204          * swsp ra,offset
 205          * swm16 reglist,offset(sp)
 206          * swm32 reglist,offset(sp)
 207          * sw32 ra,offset(sp)
 208          * jradiussp - NOT SUPPORTED
 209          *
 210          * microMIPS is way more fun...
 211          */
 212         if (mm_insn_16bit(ip->halfword[0])) {
 213                 mmi.word = (ip->halfword[0] << 16);
 214                 return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&
 215                         mmi.mm16_r5_format.rt == 31) ||
 216                        (mmi.mm16_m_format.opcode == mm_pool16c_op &&
 217                         mmi.mm16_m_format.func == mm_swm16_op);
 218         }
 219         else {
 220                 mmi.halfword[0] = ip->halfword[1];
 221                 mmi.halfword[1] = ip->halfword[0];
 222                 return (mmi.mm_m_format.opcode == mm_pool32b_op &&
 223                         mmi.mm_m_format.rd > 9 &&
 224                         mmi.mm_m_format.base == 29 &&
 225                         mmi.mm_m_format.func == mm_swm32_func) ||
 226                        (mmi.i_format.opcode == mm_sw32_op &&
 227                         mmi.i_format.rs == 29 &&
 228                         mmi.i_format.rt == 31);
 229         }
 230 #else
 231         /* sw / sd $ra, offset($sp) */
 232         return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
 233                 ip->i_format.rs == 29 &&
 234                 ip->i_format.rt == 31;
 235 #endif
 236 }
 237
 238 static inline int is_jump_ins(union mips_instruction *ip)
 239 {
 240 #ifdef CONFIG_CPU_MICROMIPS
 241         /*
 242          * jr16,jrc,jalr16,jalr16
 243          * jal
 244          * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
 245          * jraddiusp - NOT SUPPORTED
 246          *
 247          * microMIPS is kind of more fun...
 248          */
 249         union mips_instruction mmi;
 250
 251         mmi.word = (ip->halfword[0] << 16);
 252
 253         if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
 254             (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
 255             ip->j_format.opcode == mm_jal32_op)
 256                 return 1;
 257         if (ip->r_format.opcode != mm_pool32a_op ||
 258                         ip->r_format.func != mm_pool32axf_op)
 259                 return 0;
 260         return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
 261 #else
 262         if (ip->j_format.opcode == j_op)
 263                 return 1;
 264         if (ip->j_format.opcode == jal_op)
 265                 return 1;
 266         if (ip->r_format.opcode != spec_op)
 267                 return 0;
 268         return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
 269 #endif
 270 }
 271
 272 static inline int is_sp_move_ins(union mips_instruction *ip)
 273 {
 274 #ifdef CONFIG_CPU_MICROMIPS
 275         /*
 276          * addiusp -imm
 277          * addius5 sp,-imm
 278          * addiu32 sp,sp,-imm
 279          * jradiussp - NOT SUPPORTED
 280          *
 281          * microMIPS is not more fun...
 282          */
 283         if (mm_insn_16bit(ip->halfword[0])) {
 284                 union mips_instruction mmi;
 285
 286                 mmi.word = (ip->halfword[0] << 16);
 287                 return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&
 288                         mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
 289                        (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
 290                         mmi.mm16_r5_format.rt == 29);
 291         }
 292         return ip->mm_i_format.opcode == mm_addiu32_op &&
 293                ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
 294 #else
 295         /* addiu/daddiu sp,sp,-imm */
 296         if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
 297                 return 0;
 298         if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
 299                 return 1;
 300 #endif
 301         return 0;
 302 }
 303
 304 static int get_frame_info(struct mips_frame_info *info)
 305 {
 306 #ifdef CONFIG_CPU_MICROMIPS
 307         union mips_instruction *ip = (void *) (((char *) info->func) - 1);
 308 #else
 309         union mips_instruction *ip = info->func;
 310 #endif
 311         unsigned max_insns = info->func_size / sizeof(union mips_instruction);
 312         unsigned i;
 313
 314         info->pc_offset = -1;
 315         info->frame_size = 0;
 316
 317         if (!ip)
 318                 goto err;
 319
 320         if (max_insns == 0)
 321                 max_insns = 128U;       /* unknown function size */
 322         max_insns = min(128U, max_insns);
 323
 324         for (i = 0; i < max_insns; i++, ip++) {
 325
 326                 if (is_jump_ins(ip))
 327                         break;
 328                 if (!info->frame_size) {
 329                         if (is_sp_move_ins(ip))
 330                         {
 331 #ifdef CONFIG_CPU_MICROMIPS
 332                                 if (mm_insn_16bit(ip->halfword[0]))
 333                                 {
 334                                         unsigned short tmp;
 335
 336                                         if (ip->halfword[0] & mm_addiusp_func)
 337                                         {
 338                                                 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
 339                                                 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
 340                                         } else {
 341                                                 tmp = (ip->halfword[0] >> 1);
 342                                                 info->frame_size = -(signed short)(tmp & 0xf);
 343                                         }
 344                                         ip = (void *) &ip->halfword[1];
 345                                         ip--;
 346                                 } else
 347 #endif
 348                                 info->frame_size = - ip->i_format.simmediate;
 349                         }
 350                         continue;
 351                 }
 352                 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
 353                         info->pc_offset =
 354                                 ip->i_format.simmediate / sizeof(long);
 355                         break;
 356                 }
 357         }
 358         if (info->frame_size && info->pc_offset >= 0) /* nested */
 359                 return 0;
 360         if (info->pc_offset < 0) /* leaf */
 361                 return 1;
 362         /* prologue seems bogus... */
 363 err:
 364         return -1;
 365 }
 366
 367 static struct mips_frame_info schedule_mfi __read_mostly;
 368
 369 #ifdef CONFIG_KALLSYMS
 370 static unsigned long get___schedule_addr(void)
 371 {
 372         return kallsyms_lookup_name("__schedule");
 373 }
 374 #else
 375 static unsigned long get___schedule_addr(void)
 376 {
 377         union mips_instruction *ip = (void *)schedule;
 378         int max_insns = 8;
 379         int i;
 380
 381         for (i = 0; i < max_insns; i++, ip++) {
 382                 if (ip->j_format.opcode == j_op)
 383                         return J_TARGET(ip, ip->j_format.target);
 384         }
 385         return 0;
 386 }
 387 #endif
 388
 389 static int __init frame_info_init(void)
 390 {
 391         unsigned long size = 0;
 392 #ifdef CONFIG_KALLSYMS
 393         unsigned long ofs;
 394 #endif
 395         unsigned long addr;
 396
 397         addr = get___schedule_addr();
 398         if (!addr)
 399                 addr = (unsigned long)schedule;
 400
 401 #ifdef CONFIG_KALLSYMS
 402         kallsyms_lookup_size_offset(addr, &size, &ofs);
 403 #endif
 404         schedule_mfi.func = (void *)addr;
 405         schedule_mfi.func_size = size;
 406
 407         get_frame_info(&schedule_mfi);
 408
 409         /*
 410          * Without schedule() frame info, result given by
 411          * thread_saved_pc() and get_wchan() are not reliable.
 412          */
 413         if (schedule_mfi.pc_offset < 0)
 414                 printk("Can't analyze schedule() prologue at %p\n", schedule);
 415
 416         return 0;
 417 }
 418
 419 arch_initcall(frame_info_init);
 420
 421 /*
 422  * Return saved PC of a blocked thread.
 423  */
 424 unsigned long thread_saved_pc(struct task_struct *tsk)
 425 {
 426         struct thread_struct *t = &tsk->thread;
 427
 428         /* New born processes are a special case */
 429         if (t->reg31 == (unsigned long) ret_from_fork)
 430                 return t->reg31;
 431         if (schedule_mfi.pc_offset < 0)
 432                 return 0;
 433         return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
 434 }
 435
 436
 437 #ifdef CONFIG_KALLSYMS
 438 /* generic stack unwinding function */
 439 unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
 440                                               unsigned long *sp,
 441                                               unsigned long pc,
 442                                               unsigned long *ra)
 443 {
 444         struct mips_frame_info info;
 445         unsigned long size, ofs;
 446         int leaf;
 447         extern void ret_from_irq(void);
 448         extern void ret_from_exception(void);
 449
 450         if (!stack_page)
 451                 return 0;
 452
 453         /*
 454          * If we reached the bottom of interrupt context,
 455          * return saved pc in pt_regs.
 456          */
 457         if (pc == (unsigned long)ret_from_irq ||
 458             pc == (unsigned long)ret_from_exception) {
 459                 struct pt_regs *regs;
 460                 if (*sp >= stack_page &&
 461                     *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
 462                         regs = (struct pt_regs *)*sp;
 463                         pc = regs->cp0_epc;
 464                         if (!user_mode(regs) && __kernel_text_address(pc)) {
 465                                 *sp = regs->regs[29];
 466                                 *ra = regs->regs[31];
 467                                 return pc;
 468                         }
 469                 }
 470                 return 0;
 471         }
 472         if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
 473                 return 0;
 474         /*
 475          * Return ra if an exception occurred at the first instruction
 476          */
 477         if (unlikely(ofs == 0)) {
 478                 pc = *ra;
 479                 *ra = 0;
 480                 return pc;
 481         }
 482
 483         info.func = (void *)(pc - ofs);
 484         info.func_size = ofs;   /* analyze from start to ofs */
 485         leaf = get_frame_info(&info);
 486         if (leaf < 0)
 487                 return 0;
 488
 489         if (*sp < stack_page ||
 490             *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
 491                 return 0;
 492
 493         if (leaf)
 494                 /*
 495                  * For some extreme cases, get_frame_info() can
 496                  * consider wrongly a nested function as a leaf
 497                  * one. In that cases avoid to return always the
 498                  * same value.
 499                  */
 500                 pc = pc != *ra ? *ra : 0;
 501         else
 502                 pc = ((unsigned long *)(*sp))[info.pc_offset];
 503
 504         *sp += info.frame_size;
 505         *ra = 0;
 506         return __kernel_text_address(pc) ? pc : 0;
 507 }
 508 EXPORT_SYMBOL(unwind_stack_by_address);
 509
 510 /* used by show_backtrace() */
 511 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
 512                            unsigned long pc, unsigned long *ra)
 513 {
 514         unsigned long stack_page = (unsigned long)task_stack_page(task);
 515         return unwind_stack_by_address(stack_page, sp, pc, ra);
 516 }
 517 #endif
 518
 519 /*
 520  * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
 521  */
 522 unsigned long get_wchan(struct task_struct *task)
 523 {
 524         unsigned long pc = 0;
 525 #ifdef CONFIG_KALLSYMS
 526         unsigned long sp;
 527         unsigned long ra = 0;
 528 #endif
 529
 530         if (!task || task == current || task->state == TASK_RUNNING)
 531                 goto out;
 532         if (!task_stack_page(task))
 533                 goto out;
 534
 535         pc = thread_saved_pc(task);
 536
 537 #ifdef CONFIG_KALLSYMS
 538         sp = task->thread.reg29 + schedule_mfi.frame_size;
 539
 540         while (in_sched_functions(pc))
 541                 pc = unwind_stack(task, &sp, pc, &ra);
 542 #endif
 543
 544 out:
 545         return pc;
 546 }
 547
 548 /*
 549  * Don't forget that the stack pointer must be aligned on a 8 bytes
 550  * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
 551  */
 552 unsigned long arch_align_stack(unsigned long sp)
 553 {
 554         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 555                 sp -= get_random_int() & ~PAGE_MASK;
 556
 557         return sp & ALMASK;
 558 }
 559
 560 static void arch_dump_stack(void *info)
 561 {
 562         struct pt_regs *regs;
 563
 564         regs = get_irq_regs();
 565
 566         if (regs)
 567                 show_regs(regs);
 568
 569         dump_stack();
 570 }
 571
 572 void arch_trigger_all_cpu_backtrace(bool include_self)
 573 {
 574         smp_call_function(arch_dump_stack, NULL, 1);
 575 }
 576
 577 int mips_get_process_fp_mode(struct task_struct *task)
 578 {
 579         int value = 0;
 580
 581         if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS))
 582                 value |= PR_FP_MODE_FR;
 583         if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS))
 584                 value |= PR_FP_MODE_FRE;
 585
 586         return value;
 587 }
 588
 589 static void prepare_for_fp_mode_switch(void *info)
 590 {
 591         struct mm_struct *mm = info;
 592
 593         if (current->mm == mm)
 594                 lose_fpu(1);
 595 }
 596
 597 int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
 598 {
 599         const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
 600         struct task_struct *t;
 601         int max_users;
 602
 603         /* Check the value is valid */
 604         if (value & ~known_bits)
 605                 return -EOPNOTSUPP;
 606
 607         /* Avoid inadvertently triggering emulation */
 608         if ((value & PR_FP_MODE_FR) && cpu_has_fpu &&
 609             !(current_cpu_data.fpu_id & MIPS_FPIR_F64))
 610                 return -EOPNOTSUPP;
 611         if ((value & PR_FP_MODE_FRE) && cpu_has_fpu && !cpu_has_fre)
 612                 return -EOPNOTSUPP;
 613
 614         /* FR = 0 not supported in MIPS R6 */
 615         if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6)
 616                 return -EOPNOTSUPP;
 617
 618         /* Proceed with the mode switch */
 619         preempt_disable();
 620
 621         /* Save FP & vector context, then disable FPU & MSA */
 622         if (task->signal == current->signal)
 623                 lose_fpu(1);
 624
 625         /* Prevent any threads from obtaining live FP context */
 626         atomic_set(&task->mm->context.fp_mode_switching, 1);
 627         smp_mb__after_atomic();
 628
 629         /*
 630          * If there are multiple online CPUs then force any which are running
 631          * threads in this process to lose their FPU context, which they can't
 632          * regain until fp_mode_switching is cleared later.
 633          */
 634         if (num_online_cpus() > 1) {
 635                 /* No need to send an IPI for the local CPU */
 636                 max_users = (task->mm == current->mm) ? 1 : 0;
 637
 638                 if (atomic_read(&current->mm->mm_users) > max_users)
 639                         smp_call_function(prepare_for_fp_mode_switch,
 640                                           (void *)current->mm, 1);
 641         }
 642
 643         /*
 644          * There are now no threads of the process with live FP context, so it
 645          * is safe to proceed with the FP mode switch.
 646          */
 647         for_each_thread(task, t) {
 648                 /* Update desired FP register width */
 649                 if (value & PR_FP_MODE_FR) {
 650                         clear_tsk_thread_flag(t, TIF_32BIT_FPREGS);
 651                 } else {
 652                         set_tsk_thread_flag(t, TIF_32BIT_FPREGS);
 653                         clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE);
 654                 }
 655
 656                 /* Update desired FP single layout */
 657                 if (value & PR_FP_MODE_FRE)
 658                         set_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
 659                 else
 660                         clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
 661         }
 662
 663         /* Allow threads to use FP again */
 664         atomic_set(&task->mm->context.fp_mode_switching, 0);
 665         preempt_enable();
 666
 667         return 0;
 668 }