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 static inline int is_ra_save_ins(union mips_instruction *ip) 228 { 229 #ifdef CONFIG_CPU_MICROMIPS 230 union mips_instruction mmi; 231 232 /* 233 * swsp ra,offset 234 * swm16 reglist,offset(sp) 235 * swm32 reglist,offset(sp) 236 * sw32 ra,offset(sp) 237 * jradiussp - NOT SUPPORTED 238 * 239 * microMIPS is way more fun... 240 */ 241 if (mm_insn_16bit(ip->halfword[0])) { 242 mmi.word = (ip->halfword[0] << 16); 243 return ((mmi.mm16_r5_format.opcode == mm_swsp16_op && 244 mmi.mm16_r5_format.rt == 31) || 245 (mmi.mm16_m_format.opcode == mm_pool16c_op && 246 mmi.mm16_m_format.func == mm_swm16_op)); 247 } 248 else { 249 mmi.halfword[0] = ip->halfword[1]; 250 mmi.halfword[1] = ip->halfword[0]; 251 return ((mmi.mm_m_format.opcode == mm_pool32b_op && 252 mmi.mm_m_format.rd > 9 && 253 mmi.mm_m_format.base == 29 && 254 mmi.mm_m_format.func == mm_swm32_func) || 255 (mmi.i_format.opcode == mm_sw32_op && 256 mmi.i_format.rs == 29 && 257 mmi.i_format.rt == 31)); 258 } 259 #else 260 /* sw / sd $ra, offset($sp) */ 261 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && 262 ip->i_format.rs == 29 && 263 ip->i_format.rt == 31; 264 #endif 265 } 266 267 static inline int is_jal_jalr_jr_ins(union mips_instruction *ip) 268 { 269 #ifdef CONFIG_CPU_MICROMIPS 270 /* 271 * jr16,jrc,jalr16,jalr16 272 * jal 273 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb 274 * jraddiusp - NOT SUPPORTED 275 * 276 * microMIPS is kind of more fun... 277 */ 278 union mips_instruction mmi; 279 280 mmi.word = (ip->halfword[0] << 16); 281 282 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op && 283 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) || 284 ip->j_format.opcode == mm_jal32_op) 285 return 1; 286 if (ip->r_format.opcode != mm_pool32a_op || 287 ip->r_format.func != mm_pool32axf_op) 288 return 0; 289 return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op); 290 #else 291 if (ip->j_format.opcode == jal_op) 292 return 1; 293 if (ip->r_format.opcode != spec_op) 294 return 0; 295 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; 296 #endif 297 } 298 299 static inline int is_sp_move_ins(union mips_instruction *ip) 300 { 301 #ifdef CONFIG_CPU_MICROMIPS 302 /* 303 * addiusp -imm 304 * addius5 sp,-imm 305 * addiu32 sp,sp,-imm 306 * jradiussp - NOT SUPPORTED 307 * 308 * microMIPS is not more fun... 309 */ 310 if (mm_insn_16bit(ip->halfword[0])) { 311 union mips_instruction mmi; 312 313 mmi.word = (ip->halfword[0] << 16); 314 return ((mmi.mm16_r3_format.opcode == mm_pool16d_op && 315 mmi.mm16_r3_format.simmediate && mm_addiusp_func) || 316 (mmi.mm16_r5_format.opcode == mm_pool16d_op && 317 mmi.mm16_r5_format.rt == 29)); 318 } 319 return (ip->mm_i_format.opcode == mm_addiu32_op && 320 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29); 321 #else 322 /* addiu/daddiu sp,sp,-imm */ 323 if (ip->i_format.rs != 29 || ip->i_format.rt != 29) 324 return 0; 325 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) 326 return 1; 327 #endif 328 return 0; 329 } 330 331 static int get_frame_info(struct mips_frame_info *info) 332 { 333 #ifdef CONFIG_CPU_MICROMIPS 334 union mips_instruction *ip = (void *) (((char *) info->func) - 1); 335 #else 336 union mips_instruction *ip = info->func; 337 #endif 338 unsigned max_insns = info->func_size / sizeof(union mips_instruction); 339 unsigned i; 340 341 info->pc_offset = -1; 342 info->frame_size = 0; 343 344 if (!ip) 345 goto err; 346 347 if (max_insns == 0) 348 max_insns = 128U; /* unknown function size */ 349 max_insns = min(128U, max_insns); 350 351 for (i = 0; i < max_insns; i++, ip++) { 352 353 if (is_jal_jalr_jr_ins(ip)) 354 break; 355 if (!info->frame_size) { 356 if (is_sp_move_ins(ip)) 357 { 358 #ifdef CONFIG_CPU_MICROMIPS 359 if (mm_insn_16bit(ip->halfword[0])) 360 { 361 unsigned short tmp; 362 363 if (ip->halfword[0] & mm_addiusp_func) 364 { 365 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2); 366 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0)); 367 } else { 368 tmp = (ip->halfword[0] >> 1); 369 info->frame_size = -(signed short)(tmp & 0xf); 370 } 371 ip = (void *) &ip->halfword[1]; 372 ip--; 373 } else 374 #endif 375 info->frame_size = - ip->i_format.simmediate; 376 } 377 continue; 378 } 379 if (info->pc_offset == -1 && is_ra_save_ins(ip)) { 380 info->pc_offset = 381 ip->i_format.simmediate / sizeof(long); 382 break; 383 } 384 } 385 if (info->frame_size && info->pc_offset >= 0) /* nested */ 386 return 0; 387 if (info->pc_offset < 0) /* leaf */ 388 return 1; 389 /* prologue seems boggus... */ 390 err: 391 return -1; 392 } 393 394 static struct mips_frame_info schedule_mfi __read_mostly; 395 396 static int __init frame_info_init(void) 397 { 398 unsigned long size = 0; 399 #ifdef CONFIG_KALLSYMS 400 unsigned long ofs; 401 402 kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs); 403 #endif 404 schedule_mfi.func = schedule; 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 (__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