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