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/user.h> 25 #include <linux/init.h> 26 #include <linux/completion.h> 27 #include <linux/kallsyms.h> 28 #include <linux/random.h> 29 30 #include <asm/asm.h> 31 #include <asm/bootinfo.h> 32 #include <asm/cpu.h> 33 #include <asm/dsp.h> 34 #include <asm/fpu.h> 35 #include <asm/pgtable.h> 36 #include <asm/mipsregs.h> 37 #include <asm/processor.h> 38 #include <asm/uaccess.h> 39 #include <asm/io.h> 40 #include <asm/elf.h> 41 #include <asm/isadep.h> 42 #include <asm/inst.h> 43 #include <asm/stacktrace.h> 44 45 #ifdef CONFIG_HOTPLUG_CPU 46 void arch_cpu_idle_dead(void) 47 { 48 /* What the heck is this check doing ? */ 49 if (!cpu_isset(smp_processor_id(), cpu_callin_map)) 50 play_dead(); 51 } 52 #endif 53 54 void arch_cpu_idle(void) 55 { 56 #ifdef CONFIG_MIPS_MT_SMTC 57 extern void smtc_idle_loop_hook(void); 58 59 smtc_idle_loop_hook(); 60 #endif 61 if (cpu_wait) 62 (*cpu_wait)(); 63 else 64 local_irq_enable(); 65 } 66 67 asmlinkage void ret_from_fork(void); 68 asmlinkage void ret_from_kernel_thread(void); 69 70 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) 71 { 72 unsigned long status; 73 74 /* New thread loses kernel privileges. */ 75 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); 76 #ifdef CONFIG_64BIT 77 status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR; 78 #endif 79 status |= KU_USER; 80 regs->cp0_status = status; 81 clear_used_math(); 82 clear_fpu_owner(); 83 if (cpu_has_dsp) 84 __init_dsp(); 85 regs->cp0_epc = pc; 86 regs->regs[29] = sp; 87 } 88 89 void exit_thread(void) 90 { 91 } 92 93 void flush_thread(void) 94 { 95 } 96 97 int copy_thread(unsigned long clone_flags, unsigned long usp, 98 unsigned long arg, struct task_struct *p) 99 { 100 struct thread_info *ti = task_thread_info(p); 101 struct pt_regs *childregs, *regs = current_pt_regs(); 102 unsigned long childksp; 103 p->set_child_tid = p->clear_child_tid = NULL; 104 105 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; 106 107 preempt_disable(); 108 109 if (is_fpu_owner()) 110 save_fp(p); 111 112 if (cpu_has_dsp) 113 save_dsp(p); 114 115 preempt_enable(); 116 117 /* set up new TSS. */ 118 childregs = (struct pt_regs *) childksp - 1; 119 /* Put the stack after the struct pt_regs. */ 120 childksp = (unsigned long) childregs; 121 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); 122 if (unlikely(p->flags & PF_KTHREAD)) { 123 unsigned long status = p->thread.cp0_status; 124 memset(childregs, 0, sizeof(struct pt_regs)); 125 ti->addr_limit = KERNEL_DS; 126 p->thread.reg16 = usp; /* fn */ 127 p->thread.reg17 = arg; 128 p->thread.reg29 = childksp; 129 p->thread.reg31 = (unsigned long) ret_from_kernel_thread; 130 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) 131 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | 132 ((status & (ST0_KUC | ST0_IEC)) << 2); 133 #else 134 status |= ST0_EXL; 135 #endif 136 childregs->cp0_status = status; 137 return 0; 138 } 139 *childregs = *regs; 140 childregs->regs[7] = 0; /* Clear error flag */ 141 childregs->regs[2] = 0; /* Child gets zero as return value */ 142 if (usp) 143 childregs->regs[29] = usp; 144 ti->addr_limit = USER_DS; 145 146 p->thread.reg29 = (unsigned long) childregs; 147 p->thread.reg31 = (unsigned long) ret_from_fork; 148 149 /* 150 * New tasks lose permission to use the fpu. This accelerates context 151 * switching for most programs since they don't use the fpu. 152 */ 153 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); 154 155 #ifdef CONFIG_MIPS_MT_SMTC 156 /* 157 * SMTC restores TCStatus after Status, and the CU bits 158 * are aliased there. 159 */ 160 childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1); 161 #endif 162 clear_tsk_thread_flag(p, TIF_USEDFPU); 163 164 #ifdef CONFIG_MIPS_MT_FPAFF 165 clear_tsk_thread_flag(p, TIF_FPUBOUND); 166 #endif /* CONFIG_MIPS_MT_FPAFF */ 167 168 if (clone_flags & CLONE_SETTLS) 169 ti->tp_value = regs->regs[7]; 170 171 return 0; 172 } 173 174 /* Fill in the fpu structure for a core dump.. */ 175 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) 176 { 177 memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); 178 179 return 1; 180 } 181 182 void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) 183 { 184 int i; 185 186 for (i = 0; i < EF_R0; i++) 187 gp[i] = 0; 188 gp[EF_R0] = 0; 189 for (i = 1; i <= 31; i++) 190 gp[EF_R0 + i] = regs->regs[i]; 191 gp[EF_R26] = 0; 192 gp[EF_R27] = 0; 193 gp[EF_LO] = regs->lo; 194 gp[EF_HI] = regs->hi; 195 gp[EF_CP0_EPC] = regs->cp0_epc; 196 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; 197 gp[EF_CP0_STATUS] = regs->cp0_status; 198 gp[EF_CP0_CAUSE] = regs->cp0_cause; 199 #ifdef EF_UNUSED0 200 gp[EF_UNUSED0] = 0; 201 #endif 202 } 203 204 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) 205 { 206 elf_dump_regs(*regs, task_pt_regs(tsk)); 207 return 1; 208 } 209 210 int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) 211 { 212 memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); 213 214 return 1; 215 } 216 217 /* 218 * 219 */ 220 struct mips_frame_info { 221 void *func; 222 unsigned long func_size; 223 int frame_size; 224 int pc_offset; 225 }; 226 227 #define J_TARGET(pc,target) \ 228 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2)) 229 230 static inline int is_ra_save_ins(union mips_instruction *ip) 231 { 232 #ifdef CONFIG_CPU_MICROMIPS 233 union mips_instruction mmi; 234 235 /* 236 * swsp ra,offset 237 * swm16 reglist,offset(sp) 238 * swm32 reglist,offset(sp) 239 * sw32 ra,offset(sp) 240 * jradiussp - NOT SUPPORTED 241 * 242 * microMIPS is way more fun... 243 */ 244 if (mm_insn_16bit(ip->halfword[0])) { 245 mmi.word = (ip->halfword[0] << 16); 246 return ((mmi.mm16_r5_format.opcode == mm_swsp16_op && 247 mmi.mm16_r5_format.rt == 31) || 248 (mmi.mm16_m_format.opcode == mm_pool16c_op && 249 mmi.mm16_m_format.func == mm_swm16_op)); 250 } 251 else { 252 mmi.halfword[0] = ip->halfword[1]; 253 mmi.halfword[1] = ip->halfword[0]; 254 return ((mmi.mm_m_format.opcode == mm_pool32b_op && 255 mmi.mm_m_format.rd > 9 && 256 mmi.mm_m_format.base == 29 && 257 mmi.mm_m_format.func == mm_swm32_func) || 258 (mmi.i_format.opcode == mm_sw32_op && 259 mmi.i_format.rs == 29 && 260 mmi.i_format.rt == 31)); 261 } 262 #else 263 /* sw / sd $ra, offset($sp) */ 264 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && 265 ip->i_format.rs == 29 && 266 ip->i_format.rt == 31; 267 #endif 268 } 269 270 static inline int is_jump_ins(union mips_instruction *ip) 271 { 272 #ifdef CONFIG_CPU_MICROMIPS 273 /* 274 * jr16,jrc,jalr16,jalr16 275 * jal 276 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb 277 * jraddiusp - NOT SUPPORTED 278 * 279 * microMIPS is kind of more fun... 280 */ 281 union mips_instruction mmi; 282 283 mmi.word = (ip->halfword[0] << 16); 284 285 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op && 286 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) || 287 ip->j_format.opcode == mm_jal32_op) 288 return 1; 289 if (ip->r_format.opcode != mm_pool32a_op || 290 ip->r_format.func != mm_pool32axf_op) 291 return 0; 292 return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op); 293 #else 294 if (ip->j_format.opcode == j_op) 295 return 1; 296 if (ip->j_format.opcode == jal_op) 297 return 1; 298 if (ip->r_format.opcode != spec_op) 299 return 0; 300 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; 301 #endif 302 } 303 304 static inline int is_sp_move_ins(union mips_instruction *ip) 305 { 306 #ifdef CONFIG_CPU_MICROMIPS 307 /* 308 * addiusp -imm 309 * addius5 sp,-imm 310 * addiu32 sp,sp,-imm 311 * jradiussp - NOT SUPPORTED 312 * 313 * microMIPS is not more fun... 314 */ 315 if (mm_insn_16bit(ip->halfword[0])) { 316 union mips_instruction mmi; 317 318 mmi.word = (ip->halfword[0] << 16); 319 return ((mmi.mm16_r3_format.opcode == mm_pool16d_op && 320 mmi.mm16_r3_format.simmediate && mm_addiusp_func) || 321 (mmi.mm16_r5_format.opcode == mm_pool16d_op && 322 mmi.mm16_r5_format.rt == 29)); 323 } 324 return (ip->mm_i_format.opcode == mm_addiu32_op && 325 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29); 326 #else 327 /* addiu/daddiu sp,sp,-imm */ 328 if (ip->i_format.rs != 29 || ip->i_format.rt != 29) 329 return 0; 330 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) 331 return 1; 332 #endif 333 return 0; 334 } 335 336 static int get_frame_info(struct mips_frame_info *info) 337 { 338 #ifdef CONFIG_CPU_MICROMIPS 339 union mips_instruction *ip = (void *) (((char *) info->func) - 1); 340 #else 341 union mips_instruction *ip = info->func; 342 #endif 343 unsigned max_insns = info->func_size / sizeof(union mips_instruction); 344 unsigned i; 345 346 info->pc_offset = -1; 347 info->frame_size = 0; 348 349 if (!ip) 350 goto err; 351 352 if (max_insns == 0) 353 max_insns = 128U; /* unknown function size */ 354 max_insns = min(128U, max_insns); 355 356 for (i = 0; i < max_insns; i++, ip++) { 357 358 if (is_jump_ins(ip)) 359 break; 360 if (!info->frame_size) { 361 if (is_sp_move_ins(ip)) 362 { 363 #ifdef CONFIG_CPU_MICROMIPS 364 if (mm_insn_16bit(ip->halfword[0])) 365 { 366 unsigned short tmp; 367 368 if (ip->halfword[0] & mm_addiusp_func) 369 { 370 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2); 371 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0)); 372 } else { 373 tmp = (ip->halfword[0] >> 1); 374 info->frame_size = -(signed short)(tmp & 0xf); 375 } 376 ip = (void *) &ip->halfword[1]; 377 ip--; 378 } else 379 #endif 380 info->frame_size = - ip->i_format.simmediate; 381 } 382 continue; 383 } 384 if (info->pc_offset == -1 && is_ra_save_ins(ip)) { 385 info->pc_offset = 386 ip->i_format.simmediate / sizeof(long); 387 break; 388 } 389 } 390 if (info->frame_size && info->pc_offset >= 0) /* nested */ 391 return 0; 392 if (info->pc_offset < 0) /* leaf */ 393 return 1; 394 /* prologue seems boggus... */ 395 err: 396 return -1; 397 } 398 399 static struct mips_frame_info schedule_mfi __read_mostly; 400 401 #ifdef CONFIG_KALLSYMS 402 static unsigned long get___schedule_addr(void) 403 { 404 return kallsyms_lookup_name("__schedule"); 405 } 406 #else 407 static unsigned long get___schedule_addr(void) 408 { 409 union mips_instruction *ip = (void *)schedule; 410 int max_insns = 8; 411 int i; 412 413 for (i = 0; i < max_insns; i++, ip++) { 414 if (ip->j_format.opcode == j_op) 415 return J_TARGET(ip, ip->j_format.target); 416 } 417 return 0; 418 } 419 #endif 420 421 static int __init frame_info_init(void) 422 { 423 unsigned long size = 0; 424 #ifdef CONFIG_KALLSYMS 425 unsigned long ofs; 426 #endif 427 unsigned long addr; 428 429 addr = get___schedule_addr(); 430 if (!addr) 431 addr = (unsigned long)schedule; 432 433 #ifdef CONFIG_KALLSYMS 434 kallsyms_lookup_size_offset(addr, &size, &ofs); 435 #endif 436 schedule_mfi.func = (void *)addr; 437 schedule_mfi.func_size = size; 438 439 get_frame_info(&schedule_mfi); 440 441 /* 442 * Without schedule() frame info, result given by 443 * thread_saved_pc() and get_wchan() are not reliable. 444 */ 445 if (schedule_mfi.pc_offset < 0) 446 printk("Can't analyze schedule() prologue at %p\n", schedule); 447 448 return 0; 449 } 450 451 arch_initcall(frame_info_init); 452 453 /* 454 * Return saved PC of a blocked thread. 455 */ 456 unsigned long thread_saved_pc(struct task_struct *tsk) 457 { 458 struct thread_struct *t = &tsk->thread; 459 460 /* New born processes are a special case */ 461 if (t->reg31 == (unsigned long) ret_from_fork) 462 return t->reg31; 463 if (schedule_mfi.pc_offset < 0) 464 return 0; 465 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; 466 } 467 468 469 #ifdef CONFIG_KALLSYMS 470 /* generic stack unwinding function */ 471 unsigned long notrace unwind_stack_by_address(unsigned long stack_page, 472 unsigned long *sp, 473 unsigned long pc, 474 unsigned long *ra) 475 { 476 struct mips_frame_info info; 477 unsigned long size, ofs; 478 int leaf; 479 extern void ret_from_irq(void); 480 extern void ret_from_exception(void); 481 482 if (!stack_page) 483 return 0; 484 485 /* 486 * If we reached the bottom of interrupt context, 487 * return saved pc in pt_regs. 488 */ 489 if (pc == (unsigned long)ret_from_irq || 490 pc == (unsigned long)ret_from_exception) { 491 struct pt_regs *regs; 492 if (*sp >= stack_page && 493 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { 494 regs = (struct pt_regs *)*sp; 495 pc = regs->cp0_epc; 496 if (__kernel_text_address(pc)) { 497 *sp = regs->regs[29]; 498 *ra = regs->regs[31]; 499 return pc; 500 } 501 } 502 return 0; 503 } 504 if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) 505 return 0; 506 /* 507 * Return ra if an exception occurred at the first instruction 508 */ 509 if (unlikely(ofs == 0)) { 510 pc = *ra; 511 *ra = 0; 512 return pc; 513 } 514 515 info.func = (void *)(pc - ofs); 516 info.func_size = ofs; /* analyze from start to ofs */ 517 leaf = get_frame_info(&info); 518 if (leaf < 0) 519 return 0; 520 521 if (*sp < stack_page || 522 *sp + info.frame_size > stack_page + THREAD_SIZE - 32) 523 return 0; 524 525 if (leaf) 526 /* 527 * For some extreme cases, get_frame_info() can 528 * consider wrongly a nested function as a leaf 529 * one. In that cases avoid to return always the 530 * same value. 531 */ 532 pc = pc != *ra ? *ra : 0; 533 else 534 pc = ((unsigned long *)(*sp))[info.pc_offset]; 535 536 *sp += info.frame_size; 537 *ra = 0; 538 return __kernel_text_address(pc) ? pc : 0; 539 } 540 EXPORT_SYMBOL(unwind_stack_by_address); 541 542 /* used by show_backtrace() */ 543 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, 544 unsigned long pc, unsigned long *ra) 545 { 546 unsigned long stack_page = (unsigned long)task_stack_page(task); 547 return unwind_stack_by_address(stack_page, sp, pc, ra); 548 } 549 #endif 550 551 /* 552 * get_wchan - a maintenance nightmare^W^Wpain in the ass ... 553 */ 554 unsigned long get_wchan(struct task_struct *task) 555 { 556 unsigned long pc = 0; 557 #ifdef CONFIG_KALLSYMS 558 unsigned long sp; 559 unsigned long ra = 0; 560 #endif 561 562 if (!task || task == current || task->state == TASK_RUNNING) 563 goto out; 564 if (!task_stack_page(task)) 565 goto out; 566 567 pc = thread_saved_pc(task); 568 569 #ifdef CONFIG_KALLSYMS 570 sp = task->thread.reg29 + schedule_mfi.frame_size; 571 572 while (in_sched_functions(pc)) 573 pc = unwind_stack(task, &sp, pc, &ra); 574 #endif 575 576 out: 577 return pc; 578 } 579 580 /* 581 * Don't forget that the stack pointer must be aligned on a 8 bytes 582 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. 583 */ 584 unsigned long arch_align_stack(unsigned long sp) 585 { 586 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 587 sp -= get_random_int() & ~PAGE_MASK; 588 589 return sp & ALMASK; 590 } 591