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/msa.h> 36 #include <asm/pgtable.h> 37 #include <asm/mipsregs.h> 38 #include <asm/processor.h> 39 #include <asm/uaccess.h> 40 #include <asm/io.h> 41 #include <asm/elf.h> 42 #include <asm/isadep.h> 43 #include <asm/inst.h> 44 #include <asm/stacktrace.h> 45 46 #ifdef CONFIG_HOTPLUG_CPU 47 void arch_cpu_idle_dead(void) 48 { 49 /* What the heck is this check doing ? */ 50 if (!cpu_isset(smp_processor_id(), cpu_callin_map)) 51 play_dead(); 52 } 53 #endif 54 55 asmlinkage void ret_from_fork(void); 56 asmlinkage void ret_from_kernel_thread(void); 57 58 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) 59 { 60 unsigned long status; 61 62 /* New thread loses kernel privileges. */ 63 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); 64 status |= KU_USER; 65 regs->cp0_status = status; 66 clear_used_math(); 67 clear_fpu_owner(); 68 init_dsp(); 69 clear_thread_flag(TIF_MSA_CTX_LIVE); 70 disable_msa(); 71 regs->cp0_epc = pc; 72 regs->regs[29] = sp; 73 } 74 75 void exit_thread(void) 76 { 77 } 78 79 void flush_thread(void) 80 { 81 } 82 83 int copy_thread(unsigned long clone_flags, unsigned long usp, 84 unsigned long arg, struct task_struct *p) 85 { 86 struct thread_info *ti = task_thread_info(p); 87 struct pt_regs *childregs, *regs = current_pt_regs(); 88 unsigned long childksp; 89 p->set_child_tid = p->clear_child_tid = NULL; 90 91 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; 92 93 preempt_disable(); 94 95 if (is_msa_enabled()) 96 save_msa(p); 97 else if (is_fpu_owner()) 98 save_fp(p); 99 100 if (cpu_has_dsp) 101 save_dsp(p); 102 103 preempt_enable(); 104 105 /* set up new TSS. */ 106 childregs = (struct pt_regs *) childksp - 1; 107 /* Put the stack after the struct pt_regs. */ 108 childksp = (unsigned long) childregs; 109 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); 110 if (unlikely(p->flags & PF_KTHREAD)) { 111 unsigned long status = p->thread.cp0_status; 112 memset(childregs, 0, sizeof(struct pt_regs)); 113 ti->addr_limit = KERNEL_DS; 114 p->thread.reg16 = usp; /* fn */ 115 p->thread.reg17 = arg; 116 p->thread.reg29 = childksp; 117 p->thread.reg31 = (unsigned long) ret_from_kernel_thread; 118 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) 119 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | 120 ((status & (ST0_KUC | ST0_IEC)) << 2); 121 #else 122 status |= ST0_EXL; 123 #endif 124 childregs->cp0_status = status; 125 return 0; 126 } 127 *childregs = *regs; 128 childregs->regs[7] = 0; /* Clear error flag */ 129 childregs->regs[2] = 0; /* Child gets zero as return value */ 130 if (usp) 131 childregs->regs[29] = usp; 132 ti->addr_limit = USER_DS; 133 134 p->thread.reg29 = (unsigned long) childregs; 135 p->thread.reg31 = (unsigned long) ret_from_fork; 136 137 /* 138 * New tasks lose permission to use the fpu. This accelerates context 139 * switching for most programs since they don't use the fpu. 140 */ 141 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); 142 143 clear_tsk_thread_flag(p, TIF_USEDFPU); 144 145 #ifdef CONFIG_MIPS_MT_FPAFF 146 clear_tsk_thread_flag(p, TIF_FPUBOUND); 147 #endif /* CONFIG_MIPS_MT_FPAFF */ 148 149 if (clone_flags & CLONE_SETTLS) 150 ti->tp_value = regs->regs[7]; 151 152 return 0; 153 } 154 155 /* Fill in the fpu structure for a core dump.. */ 156 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) 157 { 158 int i; 159 160 for (i = 0; i < NUM_FPU_REGS; i++) 161 memcpy(&r[i], ¤t->thread.fpu.fpr[i], sizeof(*r)); 162 163 memcpy(&r[NUM_FPU_REGS], ¤t->thread.fpu.fcr31, 164 sizeof(current->thread.fpu.fcr31)); 165 166 return 1; 167 } 168 169 void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) 170 { 171 int i; 172 173 for (i = 0; i < EF_R0; i++) 174 gp[i] = 0; 175 gp[EF_R0] = 0; 176 for (i = 1; i <= 31; i++) 177 gp[EF_R0 + i] = regs->regs[i]; 178 gp[EF_R26] = 0; 179 gp[EF_R27] = 0; 180 gp[EF_LO] = regs->lo; 181 gp[EF_HI] = regs->hi; 182 gp[EF_CP0_EPC] = regs->cp0_epc; 183 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; 184 gp[EF_CP0_STATUS] = regs->cp0_status; 185 gp[EF_CP0_CAUSE] = regs->cp0_cause; 186 #ifdef EF_UNUSED0 187 gp[EF_UNUSED0] = 0; 188 #endif 189 } 190 191 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) 192 { 193 elf_dump_regs(*regs, task_pt_regs(tsk)); 194 return 1; 195 } 196 197 int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) 198 { 199 int i; 200 201 for (i = 0; i < NUM_FPU_REGS; i++) 202 memcpy(&fpr[i], &t->thread.fpu.fpr[i], sizeof(*fpr)); 203 204 memcpy(&fpr[NUM_FPU_REGS], &t->thread.fpu.fcr31, 205 sizeof(t->thread.fpu.fcr31)); 206 207 return 1; 208 } 209 210 #ifdef CONFIG_CC_STACKPROTECTOR 211 #include <linux/stackprotector.h> 212 unsigned long __stack_chk_guard __read_mostly; 213 EXPORT_SYMBOL(__stack_chk_guard); 214 #endif 215 216 struct mips_frame_info { 217 void *func; 218 unsigned long func_size; 219 int frame_size; 220 int pc_offset; 221 }; 222 223 #define J_TARGET(pc,target) \ 224 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2)) 225 226 static inline int is_ra_save_ins(union mips_instruction *ip) 227 { 228 #ifdef CONFIG_CPU_MICROMIPS 229 union mips_instruction mmi; 230 231 /* 232 * swsp ra,offset 233 * swm16 reglist,offset(sp) 234 * swm32 reglist,offset(sp) 235 * sw32 ra,offset(sp) 236 * jradiussp - NOT SUPPORTED 237 * 238 * microMIPS is way more fun... 239 */ 240 if (mm_insn_16bit(ip->halfword[0])) { 241 mmi.word = (ip->halfword[0] << 16); 242 return ((mmi.mm16_r5_format.opcode == mm_swsp16_op && 243 mmi.mm16_r5_format.rt == 31) || 244 (mmi.mm16_m_format.opcode == mm_pool16c_op && 245 mmi.mm16_m_format.func == mm_swm16_op)); 246 } 247 else { 248 mmi.halfword[0] = ip->halfword[1]; 249 mmi.halfword[1] = ip->halfword[0]; 250 return ((mmi.mm_m_format.opcode == mm_pool32b_op && 251 mmi.mm_m_format.rd > 9 && 252 mmi.mm_m_format.base == 29 && 253 mmi.mm_m_format.func == mm_swm32_func) || 254 (mmi.i_format.opcode == mm_sw32_op && 255 mmi.i_format.rs == 29 && 256 mmi.i_format.rt == 31)); 257 } 258 #else 259 /* sw / sd $ra, offset($sp) */ 260 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && 261 ip->i_format.rs == 29 && 262 ip->i_format.rt == 31; 263 #endif 264 } 265 266 static inline int is_jump_ins(union mips_instruction *ip) 267 { 268 #ifdef CONFIG_CPU_MICROMIPS 269 /* 270 * jr16,jrc,jalr16,jalr16 271 * jal 272 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb 273 * jraddiusp - NOT SUPPORTED 274 * 275 * microMIPS is kind of more fun... 276 */ 277 union mips_instruction mmi; 278 279 mmi.word = (ip->halfword[0] << 16); 280 281 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op && 282 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) || 283 ip->j_format.opcode == mm_jal32_op) 284 return 1; 285 if (ip->r_format.opcode != mm_pool32a_op || 286 ip->r_format.func != mm_pool32axf_op) 287 return 0; 288 return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op); 289 #else 290 if (ip->j_format.opcode == j_op) 291 return 1; 292 if (ip->j_format.opcode == jal_op) 293 return 1; 294 if (ip->r_format.opcode != spec_op) 295 return 0; 296 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; 297 #endif 298 } 299 300 static inline int is_sp_move_ins(union mips_instruction *ip) 301 { 302 #ifdef CONFIG_CPU_MICROMIPS 303 /* 304 * addiusp -imm 305 * addius5 sp,-imm 306 * addiu32 sp,sp,-imm 307 * jradiussp - NOT SUPPORTED 308 * 309 * microMIPS is not more fun... 310 */ 311 if (mm_insn_16bit(ip->halfword[0])) { 312 union mips_instruction mmi; 313 314 mmi.word = (ip->halfword[0] << 16); 315 return ((mmi.mm16_r3_format.opcode == mm_pool16d_op && 316 mmi.mm16_r3_format.simmediate && mm_addiusp_func) || 317 (mmi.mm16_r5_format.opcode == mm_pool16d_op && 318 mmi.mm16_r5_format.rt == 29)); 319 } 320 return (ip->mm_i_format.opcode == mm_addiu32_op && 321 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29); 322 #else 323 /* addiu/daddiu sp,sp,-imm */ 324 if (ip->i_format.rs != 29 || ip->i_format.rt != 29) 325 return 0; 326 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) 327 return 1; 328 #endif 329 return 0; 330 } 331 332 static int get_frame_info(struct mips_frame_info *info) 333 { 334 #ifdef CONFIG_CPU_MICROMIPS 335 union mips_instruction *ip = (void *) (((char *) info->func) - 1); 336 #else 337 union mips_instruction *ip = info->func; 338 #endif 339 unsigned max_insns = info->func_size / sizeof(union mips_instruction); 340 unsigned i; 341 342 info->pc_offset = -1; 343 info->frame_size = 0; 344 345 if (!ip) 346 goto err; 347 348 if (max_insns == 0) 349 max_insns = 128U; /* unknown function size */ 350 max_insns = min(128U, max_insns); 351 352 for (i = 0; i < max_insns; i++, ip++) { 353 354 if (is_jump_ins(ip)) 355 break; 356 if (!info->frame_size) { 357 if (is_sp_move_ins(ip)) 358 { 359 #ifdef CONFIG_CPU_MICROMIPS 360 if (mm_insn_16bit(ip->halfword[0])) 361 { 362 unsigned short tmp; 363 364 if (ip->halfword[0] & mm_addiusp_func) 365 { 366 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2); 367 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0)); 368 } else { 369 tmp = (ip->halfword[0] >> 1); 370 info->frame_size = -(signed short)(tmp & 0xf); 371 } 372 ip = (void *) &ip->halfword[1]; 373 ip--; 374 } else 375 #endif 376 info->frame_size = - ip->i_format.simmediate; 377 } 378 continue; 379 } 380 if (info->pc_offset == -1 && is_ra_save_ins(ip)) { 381 info->pc_offset = 382 ip->i_format.simmediate / sizeof(long); 383 break; 384 } 385 } 386 if (info->frame_size && info->pc_offset >= 0) /* nested */ 387 return 0; 388 if (info->pc_offset < 0) /* leaf */ 389 return 1; 390 /* prologue seems boggus... */ 391 err: 392 return -1; 393 } 394 395 static struct mips_frame_info schedule_mfi __read_mostly; 396 397 #ifdef CONFIG_KALLSYMS 398 static unsigned long get___schedule_addr(void) 399 { 400 return kallsyms_lookup_name("__schedule"); 401 } 402 #else 403 static unsigned long get___schedule_addr(void) 404 { 405 union mips_instruction *ip = (void *)schedule; 406 int max_insns = 8; 407 int i; 408 409 for (i = 0; i < max_insns; i++, ip++) { 410 if (ip->j_format.opcode == j_op) 411 return J_TARGET(ip, ip->j_format.target); 412 } 413 return 0; 414 } 415 #endif 416 417 static int __init frame_info_init(void) 418 { 419 unsigned long size = 0; 420 #ifdef CONFIG_KALLSYMS 421 unsigned long ofs; 422 #endif 423 unsigned long addr; 424 425 addr = get___schedule_addr(); 426 if (!addr) 427 addr = (unsigned long)schedule; 428 429 #ifdef CONFIG_KALLSYMS 430 kallsyms_lookup_size_offset(addr, &size, &ofs); 431 #endif 432 schedule_mfi.func = (void *)addr; 433 schedule_mfi.func_size = size; 434 435 get_frame_info(&schedule_mfi); 436 437 /* 438 * Without schedule() frame info, result given by 439 * thread_saved_pc() and get_wchan() are not reliable. 440 */ 441 if (schedule_mfi.pc_offset < 0) 442 printk("Can't analyze schedule() prologue at %p\n", schedule); 443 444 return 0; 445 } 446 447 arch_initcall(frame_info_init); 448 449 /* 450 * Return saved PC of a blocked thread. 451 */ 452 unsigned long thread_saved_pc(struct task_struct *tsk) 453 { 454 struct thread_struct *t = &tsk->thread; 455 456 /* New born processes are a special case */ 457 if (t->reg31 == (unsigned long) ret_from_fork) 458 return t->reg31; 459 if (schedule_mfi.pc_offset < 0) 460 return 0; 461 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; 462 } 463 464 465 #ifdef CONFIG_KALLSYMS 466 /* generic stack unwinding function */ 467 unsigned long notrace unwind_stack_by_address(unsigned long stack_page, 468 unsigned long *sp, 469 unsigned long pc, 470 unsigned long *ra) 471 { 472 struct mips_frame_info info; 473 unsigned long size, ofs; 474 int leaf; 475 extern void ret_from_irq(void); 476 extern void ret_from_exception(void); 477 478 if (!stack_page) 479 return 0; 480 481 /* 482 * If we reached the bottom of interrupt context, 483 * return saved pc in pt_regs. 484 */ 485 if (pc == (unsigned long)ret_from_irq || 486 pc == (unsigned long)ret_from_exception) { 487 struct pt_regs *regs; 488 if (*sp >= stack_page && 489 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { 490 regs = (struct pt_regs *)*sp; 491 pc = regs->cp0_epc; 492 if (__kernel_text_address(pc)) { 493 *sp = regs->regs[29]; 494 *ra = regs->regs[31]; 495 return pc; 496 } 497 } 498 return 0; 499 } 500 if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) 501 return 0; 502 /* 503 * Return ra if an exception occurred at the first instruction 504 */ 505 if (unlikely(ofs == 0)) { 506 pc = *ra; 507 *ra = 0; 508 return pc; 509 } 510 511 info.func = (void *)(pc - ofs); 512 info.func_size = ofs; /* analyze from start to ofs */ 513 leaf = get_frame_info(&info); 514 if (leaf < 0) 515 return 0; 516 517 if (*sp < stack_page || 518 *sp + info.frame_size > stack_page + THREAD_SIZE - 32) 519 return 0; 520 521 if (leaf) 522 /* 523 * For some extreme cases, get_frame_info() can 524 * consider wrongly a nested function as a leaf 525 * one. In that cases avoid to return always the 526 * same value. 527 */ 528 pc = pc != *ra ? *ra : 0; 529 else 530 pc = ((unsigned long *)(*sp))[info.pc_offset]; 531 532 *sp += info.frame_size; 533 *ra = 0; 534 return __kernel_text_address(pc) ? pc : 0; 535 } 536 EXPORT_SYMBOL(unwind_stack_by_address); 537 538 /* used by show_backtrace() */ 539 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, 540 unsigned long pc, unsigned long *ra) 541 { 542 unsigned long stack_page = (unsigned long)task_stack_page(task); 543 return unwind_stack_by_address(stack_page, sp, pc, ra); 544 } 545 #endif 546 547 /* 548 * get_wchan - a maintenance nightmare^W^Wpain in the ass ... 549 */ 550 unsigned long get_wchan(struct task_struct *task) 551 { 552 unsigned long pc = 0; 553 #ifdef CONFIG_KALLSYMS 554 unsigned long sp; 555 unsigned long ra = 0; 556 #endif 557 558 if (!task || task == current || task->state == TASK_RUNNING) 559 goto out; 560 if (!task_stack_page(task)) 561 goto out; 562 563 pc = thread_saved_pc(task); 564 565 #ifdef CONFIG_KALLSYMS 566 sp = task->thread.reg29 + schedule_mfi.frame_size; 567 568 while (in_sched_functions(pc)) 569 pc = unwind_stack(task, &sp, pc, &ra); 570 #endif 571 572 out: 573 return pc; 574 } 575 576 /* 577 * Don't forget that the stack pointer must be aligned on a 8 bytes 578 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. 579 */ 580 unsigned long arch_align_stack(unsigned long sp) 581 { 582 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 583 sp -= get_random_int() & ~PAGE_MASK; 584 585 return sp & ALMASK; 586 } 587