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/sched/debug.h> 15 #include <linux/sched/task.h> 16 #include <linux/sched/task_stack.h> 17 #include <linux/tick.h> 18 #include <linux/kernel.h> 19 #include <linux/mm.h> 20 #include <linux/stddef.h> 21 #include <linux/unistd.h> 22 #include <linux/export.h> 23 #include <linux/ptrace.h> 24 #include <linux/mman.h> 25 #include <linux/personality.h> 26 #include <linux/sys.h> 27 #include <linux/init.h> 28 #include <linux/completion.h> 29 #include <linux/kallsyms.h> 30 #include <linux/random.h> 31 #include <linux/prctl.h> 32 33 #include <asm/asm.h> 34 #include <asm/bootinfo.h> 35 #include <asm/cpu.h> 36 #include <asm/dsemul.h> 37 #include <asm/dsp.h> 38 #include <asm/fpu.h> 39 #include <asm/irq.h> 40 #include <asm/msa.h> 41 #include <asm/pgtable.h> 42 #include <asm/mipsregs.h> 43 #include <asm/processor.h> 44 #include <asm/reg.h> 45 #include <linux/uaccess.h> 46 #include <asm/io.h> 47 #include <asm/elf.h> 48 #include <asm/isadep.h> 49 #include <asm/inst.h> 50 #include <asm/stacktrace.h> 51 #include <asm/irq_regs.h> 52 53 #ifdef CONFIG_HOTPLUG_CPU 54 void arch_cpu_idle_dead(void) 55 { 56 play_dead(); 57 } 58 #endif 59 60 asmlinkage void ret_from_fork(void); 61 asmlinkage void ret_from_kernel_thread(void); 62 63 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) 64 { 65 unsigned long status; 66 67 /* New thread loses kernel privileges. */ 68 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); 69 status |= KU_USER; 70 regs->cp0_status = status; 71 lose_fpu(0); 72 clear_thread_flag(TIF_MSA_CTX_LIVE); 73 clear_used_math(); 74 atomic_set(¤t->thread.bd_emu_frame, BD_EMUFRAME_NONE); 75 init_dsp(); 76 regs->cp0_epc = pc; 77 regs->regs[29] = sp; 78 } 79 80 void exit_thread(struct task_struct *tsk) 81 { 82 /* 83 * User threads may have allocated a delay slot emulation frame. 84 * If so, clean up that allocation. 85 */ 86 if (!(current->flags & PF_KTHREAD)) 87 dsemul_thread_cleanup(tsk); 88 } 89 90 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 91 { 92 /* 93 * Save any process state which is live in hardware registers to the 94 * parent context prior to duplication. This prevents the new child 95 * state becoming stale if the parent is preempted before copy_thread() 96 * gets a chance to save the parent's live hardware registers to the 97 * child context. 98 */ 99 preempt_disable(); 100 101 if (is_msa_enabled()) 102 save_msa(current); 103 else if (is_fpu_owner()) 104 _save_fp(current); 105 106 save_dsp(current); 107 108 preempt_enable(); 109 110 *dst = *src; 111 return 0; 112 } 113 114 /* 115 * Copy architecture-specific thread state 116 */ 117 int copy_thread_tls(unsigned long clone_flags, unsigned long usp, 118 unsigned long kthread_arg, struct task_struct *p, unsigned long tls) 119 { 120 struct thread_info *ti = task_thread_info(p); 121 struct pt_regs *childregs, *regs = current_pt_regs(); 122 unsigned long childksp; 123 124 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; 125 126 /* set up new TSS. */ 127 childregs = (struct pt_regs *) childksp - 1; 128 /* Put the stack after the struct pt_regs. */ 129 childksp = (unsigned long) childregs; 130 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); 131 if (unlikely(p->flags & PF_KTHREAD)) { 132 /* kernel thread */ 133 unsigned long status = p->thread.cp0_status; 134 memset(childregs, 0, sizeof(struct pt_regs)); 135 ti->addr_limit = KERNEL_DS; 136 p->thread.reg16 = usp; /* fn */ 137 p->thread.reg17 = kthread_arg; 138 p->thread.reg29 = childksp; 139 p->thread.reg31 = (unsigned long) ret_from_kernel_thread; 140 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) 141 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | 142 ((status & (ST0_KUC | ST0_IEC)) << 2); 143 #else 144 status |= ST0_EXL; 145 #endif 146 childregs->cp0_status = status; 147 return 0; 148 } 149 150 /* user thread */ 151 *childregs = *regs; 152 childregs->regs[7] = 0; /* Clear error flag */ 153 childregs->regs[2] = 0; /* Child gets zero as return value */ 154 if (usp) 155 childregs->regs[29] = usp; 156 ti->addr_limit = USER_DS; 157 158 p->thread.reg29 = (unsigned long) childregs; 159 p->thread.reg31 = (unsigned long) ret_from_fork; 160 161 /* 162 * New tasks lose permission to use the fpu. This accelerates context 163 * switching for most programs since they don't use the fpu. 164 */ 165 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); 166 167 clear_tsk_thread_flag(p, TIF_USEDFPU); 168 clear_tsk_thread_flag(p, TIF_USEDMSA); 169 clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE); 170 171 #ifdef CONFIG_MIPS_MT_FPAFF 172 clear_tsk_thread_flag(p, TIF_FPUBOUND); 173 #endif /* CONFIG_MIPS_MT_FPAFF */ 174 175 atomic_set(&p->thread.bd_emu_frame, BD_EMUFRAME_NONE); 176 177 if (clone_flags & CLONE_SETTLS) 178 ti->tp_value = tls; 179 180 return 0; 181 } 182 183 #ifdef CONFIG_CC_STACKPROTECTOR 184 #include <linux/stackprotector.h> 185 unsigned long __stack_chk_guard __read_mostly; 186 EXPORT_SYMBOL(__stack_chk_guard); 187 #endif 188 189 struct mips_frame_info { 190 void *func; 191 unsigned long func_size; 192 int frame_size; 193 int pc_offset; 194 }; 195 196 #define J_TARGET(pc,target) \ 197 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2)) 198 199 static inline int is_ra_save_ins(union mips_instruction *ip, int *poff) 200 { 201 #ifdef CONFIG_CPU_MICROMIPS 202 /* 203 * swsp ra,offset 204 * swm16 reglist,offset(sp) 205 * swm32 reglist,offset(sp) 206 * sw32 ra,offset(sp) 207 * jradiussp - NOT SUPPORTED 208 * 209 * microMIPS is way more fun... 210 */ 211 if (mm_insn_16bit(ip->word >> 16)) { 212 switch (ip->mm16_r5_format.opcode) { 213 case mm_swsp16_op: 214 if (ip->mm16_r5_format.rt != 31) 215 return 0; 216 217 *poff = ip->mm16_r5_format.imm; 218 *poff = (*poff << 2) / sizeof(ulong); 219 return 1; 220 221 case mm_pool16c_op: 222 switch (ip->mm16_m_format.func) { 223 case mm_swm16_op: 224 *poff = ip->mm16_m_format.imm; 225 *poff += 1 + ip->mm16_m_format.rlist; 226 *poff = (*poff << 2) / sizeof(ulong); 227 return 1; 228 229 default: 230 return 0; 231 } 232 233 default: 234 return 0; 235 } 236 } 237 238 switch (ip->i_format.opcode) { 239 case mm_sw32_op: 240 if (ip->i_format.rs != 29) 241 return 0; 242 if (ip->i_format.rt != 31) 243 return 0; 244 245 *poff = ip->i_format.simmediate / sizeof(ulong); 246 return 1; 247 248 case mm_pool32b_op: 249 switch (ip->mm_m_format.func) { 250 case mm_swm32_func: 251 if (ip->mm_m_format.rd < 0x10) 252 return 0; 253 if (ip->mm_m_format.base != 29) 254 return 0; 255 256 *poff = ip->mm_m_format.simmediate; 257 *poff += (ip->mm_m_format.rd & 0xf) * sizeof(u32); 258 *poff /= sizeof(ulong); 259 return 1; 260 default: 261 return 0; 262 } 263 264 default: 265 return 0; 266 } 267 #else 268 /* sw / sd $ra, offset($sp) */ 269 if ((ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && 270 ip->i_format.rs == 29 && ip->i_format.rt == 31) { 271 *poff = ip->i_format.simmediate / sizeof(ulong); 272 return 1; 273 } 274 275 return 0; 276 #endif 277 } 278 279 static inline int is_jump_ins(union mips_instruction *ip) 280 { 281 #ifdef CONFIG_CPU_MICROMIPS 282 /* 283 * jr16,jrc,jalr16,jalr16 284 * jal 285 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb 286 * jraddiusp - NOT SUPPORTED 287 * 288 * microMIPS is kind of more fun... 289 */ 290 if (mm_insn_16bit(ip->word >> 16)) { 291 if ((ip->mm16_r5_format.opcode == mm_pool16c_op && 292 (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op)) 293 return 1; 294 return 0; 295 } 296 297 if (ip->j_format.opcode == mm_j32_op) 298 return 1; 299 if (ip->j_format.opcode == mm_jal32_op) 300 return 1; 301 if (ip->r_format.opcode != mm_pool32a_op || 302 ip->r_format.func != mm_pool32axf_op) 303 return 0; 304 return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op; 305 #else 306 if (ip->j_format.opcode == j_op) 307 return 1; 308 if (ip->j_format.opcode == jal_op) 309 return 1; 310 if (ip->r_format.opcode != spec_op) 311 return 0; 312 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; 313 #endif 314 } 315 316 static inline int is_sp_move_ins(union mips_instruction *ip, int *frame_size) 317 { 318 #ifdef CONFIG_CPU_MICROMIPS 319 unsigned short tmp; 320 321 /* 322 * addiusp -imm 323 * addius5 sp,-imm 324 * addiu32 sp,sp,-imm 325 * jradiussp - NOT SUPPORTED 326 * 327 * microMIPS is not more fun... 328 */ 329 if (mm_insn_16bit(ip->word >> 16)) { 330 if (ip->mm16_r3_format.opcode == mm_pool16d_op && 331 ip->mm16_r3_format.simmediate & mm_addiusp_func) { 332 tmp = ip->mm_b0_format.simmediate >> 1; 333 tmp = ((tmp & 0x1ff) ^ 0x100) - 0x100; 334 if ((tmp + 2) < 4) /* 0x0,0x1,0x1fe,0x1ff are special */ 335 tmp ^= 0x100; 336 *frame_size = -(signed short)(tmp << 2); 337 return 1; 338 } 339 if (ip->mm16_r5_format.opcode == mm_pool16d_op && 340 ip->mm16_r5_format.rt == 29) { 341 tmp = ip->mm16_r5_format.imm >> 1; 342 *frame_size = -(signed short)(tmp & 0xf); 343 return 1; 344 } 345 return 0; 346 } 347 348 if (ip->mm_i_format.opcode == mm_addiu32_op && 349 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29) { 350 *frame_size = -ip->i_format.simmediate; 351 return 1; 352 } 353 #else 354 /* addiu/daddiu sp,sp,-imm */ 355 if (ip->i_format.rs != 29 || ip->i_format.rt != 29) 356 return 0; 357 358 if (ip->i_format.opcode == addiu_op || 359 ip->i_format.opcode == daddiu_op) { 360 *frame_size = -ip->i_format.simmediate; 361 return 1; 362 } 363 #endif 364 return 0; 365 } 366 367 static int get_frame_info(struct mips_frame_info *info) 368 { 369 bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS); 370 union mips_instruction insn, *ip, *ip_end; 371 const unsigned int max_insns = 128; 372 unsigned int last_insn_size = 0; 373 unsigned int i; 374 bool saw_jump = false; 375 376 info->pc_offset = -1; 377 info->frame_size = 0; 378 379 ip = (void *)msk_isa16_mode((ulong)info->func); 380 if (!ip) 381 goto err; 382 383 ip_end = (void *)ip + info->func_size; 384 385 for (i = 0; i < max_insns && ip < ip_end; i++) { 386 ip = (void *)ip + last_insn_size; 387 if (is_mmips && mm_insn_16bit(ip->halfword[0])) { 388 insn.word = ip->halfword[0] << 16; 389 last_insn_size = 2; 390 } else if (is_mmips) { 391 insn.word = ip->halfword[0] << 16 | ip->halfword[1]; 392 last_insn_size = 4; 393 } else { 394 insn.word = ip->word; 395 last_insn_size = 4; 396 } 397 398 if (!info->frame_size) { 399 is_sp_move_ins(&insn, &info->frame_size); 400 continue; 401 } else if (!saw_jump && is_jump_ins(ip)) { 402 /* 403 * If we see a jump instruction, we are finished 404 * with the frame save. 405 * 406 * Some functions can have a shortcut return at 407 * the beginning of the function, so don't start 408 * looking for jump instruction until we see the 409 * frame setup. 410 * 411 * The RA save instruction can get put into the 412 * delay slot of the jump instruction, so look 413 * at the next instruction, too. 414 */ 415 saw_jump = true; 416 continue; 417 } 418 if (info->pc_offset == -1 && 419 is_ra_save_ins(&insn, &info->pc_offset)) 420 break; 421 if (saw_jump) 422 break; 423 } 424 if (info->frame_size && info->pc_offset >= 0) /* nested */ 425 return 0; 426 if (info->pc_offset < 0) /* leaf */ 427 return 1; 428 /* prologue seems bogus... */ 429 err: 430 return -1; 431 } 432 433 static struct mips_frame_info schedule_mfi __read_mostly; 434 435 #ifdef CONFIG_KALLSYMS 436 static unsigned long get___schedule_addr(void) 437 { 438 return kallsyms_lookup_name("__schedule"); 439 } 440 #else 441 static unsigned long get___schedule_addr(void) 442 { 443 union mips_instruction *ip = (void *)schedule; 444 int max_insns = 8; 445 int i; 446 447 for (i = 0; i < max_insns; i++, ip++) { 448 if (ip->j_format.opcode == j_op) 449 return J_TARGET(ip, ip->j_format.target); 450 } 451 return 0; 452 } 453 #endif 454 455 static int __init frame_info_init(void) 456 { 457 unsigned long size = 0; 458 #ifdef CONFIG_KALLSYMS 459 unsigned long ofs; 460 #endif 461 unsigned long addr; 462 463 addr = get___schedule_addr(); 464 if (!addr) 465 addr = (unsigned long)schedule; 466 467 #ifdef CONFIG_KALLSYMS 468 kallsyms_lookup_size_offset(addr, &size, &ofs); 469 #endif 470 schedule_mfi.func = (void *)addr; 471 schedule_mfi.func_size = size; 472 473 get_frame_info(&schedule_mfi); 474 475 /* 476 * Without schedule() frame info, result given by 477 * thread_saved_pc() and get_wchan() are not reliable. 478 */ 479 if (schedule_mfi.pc_offset < 0) 480 printk("Can't analyze schedule() prologue at %p\n", schedule); 481 482 return 0; 483 } 484 485 arch_initcall(frame_info_init); 486 487 /* 488 * Return saved PC of a blocked thread. 489 */ 490 static unsigned long thread_saved_pc(struct task_struct *tsk) 491 { 492 struct thread_struct *t = &tsk->thread; 493 494 /* New born processes are a special case */ 495 if (t->reg31 == (unsigned long) ret_from_fork) 496 return t->reg31; 497 if (schedule_mfi.pc_offset < 0) 498 return 0; 499 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; 500 } 501 502 503 #ifdef CONFIG_KALLSYMS 504 /* generic stack unwinding function */ 505 unsigned long notrace unwind_stack_by_address(unsigned long stack_page, 506 unsigned long *sp, 507 unsigned long pc, 508 unsigned long *ra) 509 { 510 unsigned long low, high, irq_stack_high; 511 struct mips_frame_info info; 512 unsigned long size, ofs; 513 struct pt_regs *regs; 514 int leaf; 515 516 if (!stack_page) 517 return 0; 518 519 /* 520 * IRQ stacks start at IRQ_STACK_START 521 * task stacks at THREAD_SIZE - 32 522 */ 523 low = stack_page; 524 if (!preemptible() && on_irq_stack(raw_smp_processor_id(), *sp)) { 525 high = stack_page + IRQ_STACK_START; 526 irq_stack_high = high; 527 } else { 528 high = stack_page + THREAD_SIZE - 32; 529 irq_stack_high = 0; 530 } 531 532 /* 533 * If we reached the top of the interrupt stack, start unwinding 534 * the interrupted task stack. 535 */ 536 if (unlikely(*sp == irq_stack_high)) { 537 unsigned long task_sp = *(unsigned long *)*sp; 538 539 /* 540 * Check that the pointer saved in the IRQ stack head points to 541 * something within the stack of the current task 542 */ 543 if (!object_is_on_stack((void *)task_sp)) 544 return 0; 545 546 /* 547 * Follow pointer to tasks kernel stack frame where interrupted 548 * state was saved. 549 */ 550 regs = (struct pt_regs *)task_sp; 551 pc = regs->cp0_epc; 552 if (!user_mode(regs) && __kernel_text_address(pc)) { 553 *sp = regs->regs[29]; 554 *ra = regs->regs[31]; 555 return pc; 556 } 557 return 0; 558 } 559 if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) 560 return 0; 561 /* 562 * Return ra if an exception occurred at the first instruction 563 */ 564 if (unlikely(ofs == 0)) { 565 pc = *ra; 566 *ra = 0; 567 return pc; 568 } 569 570 info.func = (void *)(pc - ofs); 571 info.func_size = ofs; /* analyze from start to ofs */ 572 leaf = get_frame_info(&info); 573 if (leaf < 0) 574 return 0; 575 576 if (*sp < low || *sp + info.frame_size > high) 577 return 0; 578 579 if (leaf) 580 /* 581 * For some extreme cases, get_frame_info() can 582 * consider wrongly a nested function as a leaf 583 * one. In that cases avoid to return always the 584 * same value. 585 */ 586 pc = pc != *ra ? *ra : 0; 587 else 588 pc = ((unsigned long *)(*sp))[info.pc_offset]; 589 590 *sp += info.frame_size; 591 *ra = 0; 592 return __kernel_text_address(pc) ? pc : 0; 593 } 594 EXPORT_SYMBOL(unwind_stack_by_address); 595 596 /* used by show_backtrace() */ 597 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, 598 unsigned long pc, unsigned long *ra) 599 { 600 unsigned long stack_page = 0; 601 int cpu; 602 603 for_each_possible_cpu(cpu) { 604 if (on_irq_stack(cpu, *sp)) { 605 stack_page = (unsigned long)irq_stack[cpu]; 606 break; 607 } 608 } 609 610 if (!stack_page) 611 stack_page = (unsigned long)task_stack_page(task); 612 613 return unwind_stack_by_address(stack_page, sp, pc, ra); 614 } 615 #endif 616 617 /* 618 * get_wchan - a maintenance nightmare^W^Wpain in the ass ... 619 */ 620 unsigned long get_wchan(struct task_struct *task) 621 { 622 unsigned long pc = 0; 623 #ifdef CONFIG_KALLSYMS 624 unsigned long sp; 625 unsigned long ra = 0; 626 #endif 627 628 if (!task || task == current || task->state == TASK_RUNNING) 629 goto out; 630 if (!task_stack_page(task)) 631 goto out; 632 633 pc = thread_saved_pc(task); 634 635 #ifdef CONFIG_KALLSYMS 636 sp = task->thread.reg29 + schedule_mfi.frame_size; 637 638 while (in_sched_functions(pc)) 639 pc = unwind_stack(task, &sp, pc, &ra); 640 #endif 641 642 out: 643 return pc; 644 } 645 646 /* 647 * Don't forget that the stack pointer must be aligned on a 8 bytes 648 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. 649 */ 650 unsigned long arch_align_stack(unsigned long sp) 651 { 652 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 653 sp -= get_random_int() & ~PAGE_MASK; 654 655 return sp & ALMASK; 656 } 657 658 static void arch_dump_stack(void *info) 659 { 660 struct pt_regs *regs; 661 662 regs = get_irq_regs(); 663 664 if (regs) 665 show_regs(regs); 666 667 dump_stack(); 668 } 669 670 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) 671 { 672 long this_cpu = get_cpu(); 673 674 if (cpumask_test_cpu(this_cpu, mask) && !exclude_self) 675 dump_stack(); 676 677 smp_call_function_many(mask, arch_dump_stack, NULL, 1); 678 679 put_cpu(); 680 } 681 682 int mips_get_process_fp_mode(struct task_struct *task) 683 { 684 int value = 0; 685 686 if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS)) 687 value |= PR_FP_MODE_FR; 688 if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS)) 689 value |= PR_FP_MODE_FRE; 690 691 return value; 692 } 693 694 static void prepare_for_fp_mode_switch(void *info) 695 { 696 struct mm_struct *mm = info; 697 698 if (current->mm == mm) 699 lose_fpu(1); 700 } 701 702 int mips_set_process_fp_mode(struct task_struct *task, unsigned int value) 703 { 704 const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE; 705 struct task_struct *t; 706 int max_users; 707 708 /* If nothing to change, return right away, successfully. */ 709 if (value == mips_get_process_fp_mode(task)) 710 return 0; 711 712 /* Only accept a mode change if 64-bit FP enabled for o32. */ 713 if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT)) 714 return -EOPNOTSUPP; 715 716 /* And only for o32 tasks. */ 717 if (IS_ENABLED(CONFIG_64BIT) && !test_thread_flag(TIF_32BIT_REGS)) 718 return -EOPNOTSUPP; 719 720 /* Check the value is valid */ 721 if (value & ~known_bits) 722 return -EOPNOTSUPP; 723 724 /* Avoid inadvertently triggering emulation */ 725 if ((value & PR_FP_MODE_FR) && raw_cpu_has_fpu && 726 !(raw_current_cpu_data.fpu_id & MIPS_FPIR_F64)) 727 return -EOPNOTSUPP; 728 if ((value & PR_FP_MODE_FRE) && raw_cpu_has_fpu && !cpu_has_fre) 729 return -EOPNOTSUPP; 730 731 /* FR = 0 not supported in MIPS R6 */ 732 if (!(value & PR_FP_MODE_FR) && raw_cpu_has_fpu && cpu_has_mips_r6) 733 return -EOPNOTSUPP; 734 735 /* Proceed with the mode switch */ 736 preempt_disable(); 737 738 /* Save FP & vector context, then disable FPU & MSA */ 739 if (task->signal == current->signal) 740 lose_fpu(1); 741 742 /* Prevent any threads from obtaining live FP context */ 743 atomic_set(&task->mm->context.fp_mode_switching, 1); 744 smp_mb__after_atomic(); 745 746 /* 747 * If there are multiple online CPUs then force any which are running 748 * threads in this process to lose their FPU context, which they can't 749 * regain until fp_mode_switching is cleared later. 750 */ 751 if (num_online_cpus() > 1) { 752 /* No need to send an IPI for the local CPU */ 753 max_users = (task->mm == current->mm) ? 1 : 0; 754 755 if (atomic_read(¤t->mm->mm_users) > max_users) 756 smp_call_function(prepare_for_fp_mode_switch, 757 (void *)current->mm, 1); 758 } 759 760 /* 761 * There are now no threads of the process with live FP context, so it 762 * is safe to proceed with the FP mode switch. 763 */ 764 for_each_thread(task, t) { 765 /* Update desired FP register width */ 766 if (value & PR_FP_MODE_FR) { 767 clear_tsk_thread_flag(t, TIF_32BIT_FPREGS); 768 } else { 769 set_tsk_thread_flag(t, TIF_32BIT_FPREGS); 770 clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE); 771 } 772 773 /* Update desired FP single layout */ 774 if (value & PR_FP_MODE_FRE) 775 set_tsk_thread_flag(t, TIF_HYBRID_FPREGS); 776 else 777 clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS); 778 } 779 780 /* Allow threads to use FP again */ 781 atomic_set(&task->mm->context.fp_mode_switching, 0); 782 preempt_enable(); 783 784 return 0; 785 } 786 787 #if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32) 788 void mips_dump_regs32(u32 *uregs, const struct pt_regs *regs) 789 { 790 unsigned int i; 791 792 for (i = MIPS32_EF_R1; i <= MIPS32_EF_R31; i++) { 793 /* k0/k1 are copied as zero. */ 794 if (i == MIPS32_EF_R26 || i == MIPS32_EF_R27) 795 uregs[i] = 0; 796 else 797 uregs[i] = regs->regs[i - MIPS32_EF_R0]; 798 } 799 800 uregs[MIPS32_EF_LO] = regs->lo; 801 uregs[MIPS32_EF_HI] = regs->hi; 802 uregs[MIPS32_EF_CP0_EPC] = regs->cp0_epc; 803 uregs[MIPS32_EF_CP0_BADVADDR] = regs->cp0_badvaddr; 804 uregs[MIPS32_EF_CP0_STATUS] = regs->cp0_status; 805 uregs[MIPS32_EF_CP0_CAUSE] = regs->cp0_cause; 806 } 807 #endif /* CONFIG_32BIT || CONFIG_MIPS32_O32 */ 808 809 #ifdef CONFIG_64BIT 810 void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs) 811 { 812 unsigned int i; 813 814 for (i = MIPS64_EF_R1; i <= MIPS64_EF_R31; i++) { 815 /* k0/k1 are copied as zero. */ 816 if (i == MIPS64_EF_R26 || i == MIPS64_EF_R27) 817 uregs[i] = 0; 818 else 819 uregs[i] = regs->regs[i - MIPS64_EF_R0]; 820 } 821 822 uregs[MIPS64_EF_LO] = regs->lo; 823 uregs[MIPS64_EF_HI] = regs->hi; 824 uregs[MIPS64_EF_CP0_EPC] = regs->cp0_epc; 825 uregs[MIPS64_EF_CP0_BADVADDR] = regs->cp0_badvaddr; 826 uregs[MIPS64_EF_CP0_STATUS] = regs->cp0_status; 827 uregs[MIPS64_EF_CP0_CAUSE] = regs->cp0_cause; 828 } 829 #endif /* CONFIG_64BIT */ 830