1 /* 2 * Derived from "arch/i386/kernel/process.c" 3 * Copyright (C) 1995 Linus Torvalds 4 * 5 * Updated and modified by Cort Dougan (cort@cs.nmt.edu) and 6 * Paul Mackerras (paulus@cs.anu.edu.au) 7 * 8 * PowerPC version 9 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 */ 16 17 #include <linux/errno.h> 18 #include <linux/sched.h> 19 #include <linux/kernel.h> 20 #include <linux/mm.h> 21 #include <linux/smp.h> 22 #include <linux/stddef.h> 23 #include <linux/unistd.h> 24 #include <linux/ptrace.h> 25 #include <linux/slab.h> 26 #include <linux/user.h> 27 #include <linux/elf.h> 28 #include <linux/init.h> 29 #include <linux/prctl.h> 30 #include <linux/init_task.h> 31 #include <linux/module.h> 32 #include <linux/kallsyms.h> 33 #include <linux/mqueue.h> 34 #include <linux/hardirq.h> 35 #include <linux/utsname.h> 36 #include <linux/ftrace.h> 37 #include <linux/kernel_stat.h> 38 #include <linux/personality.h> 39 #include <linux/random.h> 40 41 #include <asm/pgtable.h> 42 #include <asm/uaccess.h> 43 #include <asm/system.h> 44 #include <asm/io.h> 45 #include <asm/processor.h> 46 #include <asm/mmu.h> 47 #include <asm/prom.h> 48 #include <asm/machdep.h> 49 #include <asm/time.h> 50 #include <asm/syscalls.h> 51 #ifdef CONFIG_PPC64 52 #include <asm/firmware.h> 53 #endif 54 #include <linux/kprobes.h> 55 #include <linux/kdebug.h> 56 57 extern unsigned long _get_SP(void); 58 59 #ifndef CONFIG_SMP 60 struct task_struct *last_task_used_math = NULL; 61 struct task_struct *last_task_used_altivec = NULL; 62 struct task_struct *last_task_used_vsx = NULL; 63 struct task_struct *last_task_used_spe = NULL; 64 #endif 65 66 /* 67 * Make sure the floating-point register state in the 68 * the thread_struct is up to date for task tsk. 69 */ 70 void flush_fp_to_thread(struct task_struct *tsk) 71 { 72 if (tsk->thread.regs) { 73 /* 74 * We need to disable preemption here because if we didn't, 75 * another process could get scheduled after the regs->msr 76 * test but before we have finished saving the FP registers 77 * to the thread_struct. That process could take over the 78 * FPU, and then when we get scheduled again we would store 79 * bogus values for the remaining FP registers. 80 */ 81 preempt_disable(); 82 if (tsk->thread.regs->msr & MSR_FP) { 83 #ifdef CONFIG_SMP 84 /* 85 * This should only ever be called for current or 86 * for a stopped child process. Since we save away 87 * the FP register state on context switch on SMP, 88 * there is something wrong if a stopped child appears 89 * to still have its FP state in the CPU registers. 90 */ 91 BUG_ON(tsk != current); 92 #endif 93 giveup_fpu(tsk); 94 } 95 preempt_enable(); 96 } 97 } 98 99 void enable_kernel_fp(void) 100 { 101 WARN_ON(preemptible()); 102 103 #ifdef CONFIG_SMP 104 if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) 105 giveup_fpu(current); 106 else 107 giveup_fpu(NULL); /* just enables FP for kernel */ 108 #else 109 giveup_fpu(last_task_used_math); 110 #endif /* CONFIG_SMP */ 111 } 112 EXPORT_SYMBOL(enable_kernel_fp); 113 114 #ifdef CONFIG_ALTIVEC 115 void enable_kernel_altivec(void) 116 { 117 WARN_ON(preemptible()); 118 119 #ifdef CONFIG_SMP 120 if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) 121 giveup_altivec(current); 122 else 123 giveup_altivec(NULL); /* just enable AltiVec for kernel - force */ 124 #else 125 giveup_altivec(last_task_used_altivec); 126 #endif /* CONFIG_SMP */ 127 } 128 EXPORT_SYMBOL(enable_kernel_altivec); 129 130 /* 131 * Make sure the VMX/Altivec register state in the 132 * the thread_struct is up to date for task tsk. 133 */ 134 void flush_altivec_to_thread(struct task_struct *tsk) 135 { 136 if (tsk->thread.regs) { 137 preempt_disable(); 138 if (tsk->thread.regs->msr & MSR_VEC) { 139 #ifdef CONFIG_SMP 140 BUG_ON(tsk != current); 141 #endif 142 giveup_altivec(tsk); 143 } 144 preempt_enable(); 145 } 146 } 147 #endif /* CONFIG_ALTIVEC */ 148 149 #ifdef CONFIG_VSX 150 #if 0 151 /* not currently used, but some crazy RAID module might want to later */ 152 void enable_kernel_vsx(void) 153 { 154 WARN_ON(preemptible()); 155 156 #ifdef CONFIG_SMP 157 if (current->thread.regs && (current->thread.regs->msr & MSR_VSX)) 158 giveup_vsx(current); 159 else 160 giveup_vsx(NULL); /* just enable vsx for kernel - force */ 161 #else 162 giveup_vsx(last_task_used_vsx); 163 #endif /* CONFIG_SMP */ 164 } 165 EXPORT_SYMBOL(enable_kernel_vsx); 166 #endif 167 168 void giveup_vsx(struct task_struct *tsk) 169 { 170 giveup_fpu(tsk); 171 giveup_altivec(tsk); 172 __giveup_vsx(tsk); 173 } 174 175 void flush_vsx_to_thread(struct task_struct *tsk) 176 { 177 if (tsk->thread.regs) { 178 preempt_disable(); 179 if (tsk->thread.regs->msr & MSR_VSX) { 180 #ifdef CONFIG_SMP 181 BUG_ON(tsk != current); 182 #endif 183 giveup_vsx(tsk); 184 } 185 preempt_enable(); 186 } 187 } 188 #endif /* CONFIG_VSX */ 189 190 #ifdef CONFIG_SPE 191 192 void enable_kernel_spe(void) 193 { 194 WARN_ON(preemptible()); 195 196 #ifdef CONFIG_SMP 197 if (current->thread.regs && (current->thread.regs->msr & MSR_SPE)) 198 giveup_spe(current); 199 else 200 giveup_spe(NULL); /* just enable SPE for kernel - force */ 201 #else 202 giveup_spe(last_task_used_spe); 203 #endif /* __SMP __ */ 204 } 205 EXPORT_SYMBOL(enable_kernel_spe); 206 207 void flush_spe_to_thread(struct task_struct *tsk) 208 { 209 if (tsk->thread.regs) { 210 preempt_disable(); 211 if (tsk->thread.regs->msr & MSR_SPE) { 212 #ifdef CONFIG_SMP 213 BUG_ON(tsk != current); 214 #endif 215 giveup_spe(tsk); 216 } 217 preempt_enable(); 218 } 219 } 220 #endif /* CONFIG_SPE */ 221 222 #ifndef CONFIG_SMP 223 /* 224 * If we are doing lazy switching of CPU state (FP, altivec or SPE), 225 * and the current task has some state, discard it. 226 */ 227 void discard_lazy_cpu_state(void) 228 { 229 preempt_disable(); 230 if (last_task_used_math == current) 231 last_task_used_math = NULL; 232 #ifdef CONFIG_ALTIVEC 233 if (last_task_used_altivec == current) 234 last_task_used_altivec = NULL; 235 #endif /* CONFIG_ALTIVEC */ 236 #ifdef CONFIG_VSX 237 if (last_task_used_vsx == current) 238 last_task_used_vsx = NULL; 239 #endif /* CONFIG_VSX */ 240 #ifdef CONFIG_SPE 241 if (last_task_used_spe == current) 242 last_task_used_spe = NULL; 243 #endif 244 preempt_enable(); 245 } 246 #endif /* CONFIG_SMP */ 247 248 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 249 void do_send_trap(struct pt_regs *regs, unsigned long address, 250 unsigned long error_code, int signal_code, int breakpt) 251 { 252 siginfo_t info; 253 254 if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, 255 11, SIGSEGV) == NOTIFY_STOP) 256 return; 257 258 /* Deliver the signal to userspace */ 259 info.si_signo = SIGTRAP; 260 info.si_errno = breakpt; /* breakpoint or watchpoint id */ 261 info.si_code = signal_code; 262 info.si_addr = (void __user *)address; 263 force_sig_info(SIGTRAP, &info, current); 264 } 265 #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ 266 void do_dabr(struct pt_regs *regs, unsigned long address, 267 unsigned long error_code) 268 { 269 siginfo_t info; 270 271 if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, 272 11, SIGSEGV) == NOTIFY_STOP) 273 return; 274 275 if (debugger_dabr_match(regs)) 276 return; 277 278 /* Clear the DABR */ 279 set_dabr(0); 280 281 /* Deliver the signal to userspace */ 282 info.si_signo = SIGTRAP; 283 info.si_errno = 0; 284 info.si_code = TRAP_HWBKPT; 285 info.si_addr = (void __user *)address; 286 force_sig_info(SIGTRAP, &info, current); 287 } 288 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ 289 290 static DEFINE_PER_CPU(unsigned long, current_dabr); 291 292 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 293 /* 294 * Set the debug registers back to their default "safe" values. 295 */ 296 static void set_debug_reg_defaults(struct thread_struct *thread) 297 { 298 thread->iac1 = thread->iac2 = 0; 299 #if CONFIG_PPC_ADV_DEBUG_IACS > 2 300 thread->iac3 = thread->iac4 = 0; 301 #endif 302 thread->dac1 = thread->dac2 = 0; 303 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0 304 thread->dvc1 = thread->dvc2 = 0; 305 #endif 306 thread->dbcr0 = 0; 307 #ifdef CONFIG_BOOKE 308 /* 309 * Force User/Supervisor bits to b11 (user-only MSR[PR]=1) 310 */ 311 thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US | \ 312 DBCR1_IAC3US | DBCR1_IAC4US; 313 /* 314 * Force Data Address Compare User/Supervisor bits to be User-only 315 * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0. 316 */ 317 thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; 318 #else 319 thread->dbcr1 = 0; 320 #endif 321 } 322 323 static void prime_debug_regs(struct thread_struct *thread) 324 { 325 mtspr(SPRN_IAC1, thread->iac1); 326 mtspr(SPRN_IAC2, thread->iac2); 327 #if CONFIG_PPC_ADV_DEBUG_IACS > 2 328 mtspr(SPRN_IAC3, thread->iac3); 329 mtspr(SPRN_IAC4, thread->iac4); 330 #endif 331 mtspr(SPRN_DAC1, thread->dac1); 332 mtspr(SPRN_DAC2, thread->dac2); 333 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0 334 mtspr(SPRN_DVC1, thread->dvc1); 335 mtspr(SPRN_DVC2, thread->dvc2); 336 #endif 337 mtspr(SPRN_DBCR0, thread->dbcr0); 338 mtspr(SPRN_DBCR1, thread->dbcr1); 339 #ifdef CONFIG_BOOKE 340 mtspr(SPRN_DBCR2, thread->dbcr2); 341 #endif 342 } 343 /* 344 * Unless neither the old or new thread are making use of the 345 * debug registers, set the debug registers from the values 346 * stored in the new thread. 347 */ 348 static void switch_booke_debug_regs(struct thread_struct *new_thread) 349 { 350 if ((current->thread.dbcr0 & DBCR0_IDM) 351 || (new_thread->dbcr0 & DBCR0_IDM)) 352 prime_debug_regs(new_thread); 353 } 354 #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ 355 static void set_debug_reg_defaults(struct thread_struct *thread) 356 { 357 if (thread->dabr) { 358 thread->dabr = 0; 359 set_dabr(0); 360 } 361 } 362 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ 363 364 int set_dabr(unsigned long dabr) 365 { 366 __get_cpu_var(current_dabr) = dabr; 367 368 if (ppc_md.set_dabr) 369 return ppc_md.set_dabr(dabr); 370 371 /* XXX should we have a CPU_FTR_HAS_DABR ? */ 372 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 373 mtspr(SPRN_DAC1, dabr); 374 #elif defined(CONFIG_PPC_BOOK3S) 375 mtspr(SPRN_DABR, dabr); 376 #endif 377 378 379 return 0; 380 } 381 382 #ifdef CONFIG_PPC64 383 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array); 384 #endif 385 386 struct task_struct *__switch_to(struct task_struct *prev, 387 struct task_struct *new) 388 { 389 struct thread_struct *new_thread, *old_thread; 390 unsigned long flags; 391 struct task_struct *last; 392 393 #ifdef CONFIG_SMP 394 /* avoid complexity of lazy save/restore of fpu 395 * by just saving it every time we switch out if 396 * this task used the fpu during the last quantum. 397 * 398 * If it tries to use the fpu again, it'll trap and 399 * reload its fp regs. So we don't have to do a restore 400 * every switch, just a save. 401 * -- Cort 402 */ 403 if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP)) 404 giveup_fpu(prev); 405 #ifdef CONFIG_ALTIVEC 406 /* 407 * If the previous thread used altivec in the last quantum 408 * (thus changing altivec regs) then save them. 409 * We used to check the VRSAVE register but not all apps 410 * set it, so we don't rely on it now (and in fact we need 411 * to save & restore VSCR even if VRSAVE == 0). -- paulus 412 * 413 * On SMP we always save/restore altivec regs just to avoid the 414 * complexity of changing processors. 415 * -- Cort 416 */ 417 if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC)) 418 giveup_altivec(prev); 419 #endif /* CONFIG_ALTIVEC */ 420 #ifdef CONFIG_VSX 421 if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX)) 422 /* VMX and FPU registers are already save here */ 423 __giveup_vsx(prev); 424 #endif /* CONFIG_VSX */ 425 #ifdef CONFIG_SPE 426 /* 427 * If the previous thread used spe in the last quantum 428 * (thus changing spe regs) then save them. 429 * 430 * On SMP we always save/restore spe regs just to avoid the 431 * complexity of changing processors. 432 */ 433 if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE))) 434 giveup_spe(prev); 435 #endif /* CONFIG_SPE */ 436 437 #else /* CONFIG_SMP */ 438 #ifdef CONFIG_ALTIVEC 439 /* Avoid the trap. On smp this this never happens since 440 * we don't set last_task_used_altivec -- Cort 441 */ 442 if (new->thread.regs && last_task_used_altivec == new) 443 new->thread.regs->msr |= MSR_VEC; 444 #endif /* CONFIG_ALTIVEC */ 445 #ifdef CONFIG_VSX 446 if (new->thread.regs && last_task_used_vsx == new) 447 new->thread.regs->msr |= MSR_VSX; 448 #endif /* CONFIG_VSX */ 449 #ifdef CONFIG_SPE 450 /* Avoid the trap. On smp this this never happens since 451 * we don't set last_task_used_spe 452 */ 453 if (new->thread.regs && last_task_used_spe == new) 454 new->thread.regs->msr |= MSR_SPE; 455 #endif /* CONFIG_SPE */ 456 457 #endif /* CONFIG_SMP */ 458 459 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 460 switch_booke_debug_regs(&new->thread); 461 #else 462 if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) 463 set_dabr(new->thread.dabr); 464 #endif 465 466 467 new_thread = &new->thread; 468 old_thread = ¤t->thread; 469 470 #ifdef CONFIG_PPC64 471 /* 472 * Collect processor utilization data per process 473 */ 474 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 475 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 476 long unsigned start_tb, current_tb; 477 start_tb = old_thread->start_tb; 478 cu->current_tb = current_tb = mfspr(SPRN_PURR); 479 old_thread->accum_tb += (current_tb - start_tb); 480 new_thread->start_tb = current_tb; 481 } 482 #endif 483 484 local_irq_save(flags); 485 486 account_system_vtime(current); 487 account_process_vtime(current); 488 calculate_steal_time(); 489 490 /* 491 * We can't take a PMU exception inside _switch() since there is a 492 * window where the kernel stack SLB and the kernel stack are out 493 * of sync. Hard disable here. 494 */ 495 hard_irq_disable(); 496 last = _switch(old_thread, new_thread); 497 498 local_irq_restore(flags); 499 500 return last; 501 } 502 503 static int instructions_to_print = 16; 504 505 static void show_instructions(struct pt_regs *regs) 506 { 507 int i; 508 unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 * 509 sizeof(int)); 510 511 printk("Instruction dump:"); 512 513 for (i = 0; i < instructions_to_print; i++) { 514 int instr; 515 516 if (!(i % 8)) 517 printk("\n"); 518 519 #if !defined(CONFIG_BOOKE) 520 /* If executing with the IMMU off, adjust pc rather 521 * than print XXXXXXXX. 522 */ 523 if (!(regs->msr & MSR_IR)) 524 pc = (unsigned long)phys_to_virt(pc); 525 #endif 526 527 /* We use __get_user here *only* to avoid an OOPS on a 528 * bad address because the pc *should* only be a 529 * kernel address. 530 */ 531 if (!__kernel_text_address(pc) || 532 __get_user(instr, (unsigned int __user *)pc)) { 533 printk("XXXXXXXX "); 534 } else { 535 if (regs->nip == pc) 536 printk("<%08x> ", instr); 537 else 538 printk("%08x ", instr); 539 } 540 541 pc += sizeof(int); 542 } 543 544 printk("\n"); 545 } 546 547 static struct regbit { 548 unsigned long bit; 549 const char *name; 550 } msr_bits[] = { 551 {MSR_EE, "EE"}, 552 {MSR_PR, "PR"}, 553 {MSR_FP, "FP"}, 554 {MSR_VEC, "VEC"}, 555 {MSR_VSX, "VSX"}, 556 {MSR_ME, "ME"}, 557 {MSR_CE, "CE"}, 558 {MSR_DE, "DE"}, 559 {MSR_IR, "IR"}, 560 {MSR_DR, "DR"}, 561 {0, NULL} 562 }; 563 564 static void printbits(unsigned long val, struct regbit *bits) 565 { 566 const char *sep = ""; 567 568 printk("<"); 569 for (; bits->bit; ++bits) 570 if (val & bits->bit) { 571 printk("%s%s", sep, bits->name); 572 sep = ","; 573 } 574 printk(">"); 575 } 576 577 #ifdef CONFIG_PPC64 578 #define REG "%016lx" 579 #define REGS_PER_LINE 4 580 #define LAST_VOLATILE 13 581 #else 582 #define REG "%08lx" 583 #define REGS_PER_LINE 8 584 #define LAST_VOLATILE 12 585 #endif 586 587 void show_regs(struct pt_regs * regs) 588 { 589 int i, trap; 590 591 printk("NIP: "REG" LR: "REG" CTR: "REG"\n", 592 regs->nip, regs->link, regs->ctr); 593 printk("REGS: %p TRAP: %04lx %s (%s)\n", 594 regs, regs->trap, print_tainted(), init_utsname()->release); 595 printk("MSR: "REG" ", regs->msr); 596 printbits(regs->msr, msr_bits); 597 printk(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); 598 trap = TRAP(regs); 599 if (trap == 0x300 || trap == 0x600) 600 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 601 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr); 602 #else 603 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr); 604 #endif 605 printk("TASK = %p[%d] '%s' THREAD: %p", 606 current, task_pid_nr(current), current->comm, task_thread_info(current)); 607 608 #ifdef CONFIG_SMP 609 printk(" CPU: %d", raw_smp_processor_id()); 610 #endif /* CONFIG_SMP */ 611 612 for (i = 0; i < 32; i++) { 613 if ((i % REGS_PER_LINE) == 0) 614 printk("\nGPR%02d: ", i); 615 printk(REG " ", regs->gpr[i]); 616 if (i == LAST_VOLATILE && !FULL_REGS(regs)) 617 break; 618 } 619 printk("\n"); 620 #ifdef CONFIG_KALLSYMS 621 /* 622 * Lookup NIP late so we have the best change of getting the 623 * above info out without failing 624 */ 625 printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip); 626 printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link); 627 #endif 628 show_stack(current, (unsigned long *) regs->gpr[1]); 629 if (!user_mode(regs)) 630 show_instructions(regs); 631 } 632 633 void exit_thread(void) 634 { 635 discard_lazy_cpu_state(); 636 } 637 638 void flush_thread(void) 639 { 640 discard_lazy_cpu_state(); 641 642 set_debug_reg_defaults(¤t->thread); 643 } 644 645 void 646 release_thread(struct task_struct *t) 647 { 648 } 649 650 /* 651 * This gets called before we allocate a new thread and copy 652 * the current task into it. 653 */ 654 void prepare_to_copy(struct task_struct *tsk) 655 { 656 flush_fp_to_thread(current); 657 flush_altivec_to_thread(current); 658 flush_vsx_to_thread(current); 659 flush_spe_to_thread(current); 660 } 661 662 /* 663 * Copy a thread.. 664 */ 665 int copy_thread(unsigned long clone_flags, unsigned long usp, 666 unsigned long unused, struct task_struct *p, 667 struct pt_regs *regs) 668 { 669 struct pt_regs *childregs, *kregs; 670 extern void ret_from_fork(void); 671 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; 672 673 CHECK_FULL_REGS(regs); 674 /* Copy registers */ 675 sp -= sizeof(struct pt_regs); 676 childregs = (struct pt_regs *) sp; 677 *childregs = *regs; 678 if ((childregs->msr & MSR_PR) == 0) { 679 /* for kernel thread, set `current' and stackptr in new task */ 680 childregs->gpr[1] = sp + sizeof(struct pt_regs); 681 #ifdef CONFIG_PPC32 682 childregs->gpr[2] = (unsigned long) p; 683 #else 684 clear_tsk_thread_flag(p, TIF_32BIT); 685 #endif 686 p->thread.regs = NULL; /* no user register state */ 687 } else { 688 childregs->gpr[1] = usp; 689 p->thread.regs = childregs; 690 if (clone_flags & CLONE_SETTLS) { 691 #ifdef CONFIG_PPC64 692 if (!test_thread_flag(TIF_32BIT)) 693 childregs->gpr[13] = childregs->gpr[6]; 694 else 695 #endif 696 childregs->gpr[2] = childregs->gpr[6]; 697 } 698 } 699 childregs->gpr[3] = 0; /* Result from fork() */ 700 sp -= STACK_FRAME_OVERHEAD; 701 702 /* 703 * The way this works is that at some point in the future 704 * some task will call _switch to switch to the new task. 705 * That will pop off the stack frame created below and start 706 * the new task running at ret_from_fork. The new task will 707 * do some house keeping and then return from the fork or clone 708 * system call, using the stack frame created above. 709 */ 710 sp -= sizeof(struct pt_regs); 711 kregs = (struct pt_regs *) sp; 712 sp -= STACK_FRAME_OVERHEAD; 713 p->thread.ksp = sp; 714 p->thread.ksp_limit = (unsigned long)task_stack_page(p) + 715 _ALIGN_UP(sizeof(struct thread_info), 16); 716 717 #ifdef CONFIG_PPC_STD_MMU_64 718 if (cpu_has_feature(CPU_FTR_SLB)) { 719 unsigned long sp_vsid; 720 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp; 721 722 if (cpu_has_feature(CPU_FTR_1T_SEGMENT)) 723 sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T) 724 << SLB_VSID_SHIFT_1T; 725 else 726 sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M) 727 << SLB_VSID_SHIFT; 728 sp_vsid |= SLB_VSID_KERNEL | llp; 729 p->thread.ksp_vsid = sp_vsid; 730 } 731 #endif /* CONFIG_PPC_STD_MMU_64 */ 732 733 /* 734 * The PPC64 ABI makes use of a TOC to contain function 735 * pointers. The function (ret_from_except) is actually a pointer 736 * to the TOC entry. The first entry is a pointer to the actual 737 * function. 738 */ 739 #ifdef CONFIG_PPC64 740 kregs->nip = *((unsigned long *)ret_from_fork); 741 #else 742 kregs->nip = (unsigned long)ret_from_fork; 743 #endif 744 745 return 0; 746 } 747 748 /* 749 * Set up a thread for executing a new program 750 */ 751 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) 752 { 753 #ifdef CONFIG_PPC64 754 unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */ 755 #endif 756 757 set_fs(USER_DS); 758 759 /* 760 * If we exec out of a kernel thread then thread.regs will not be 761 * set. Do it now. 762 */ 763 if (!current->thread.regs) { 764 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE; 765 current->thread.regs = regs - 1; 766 } 767 768 memset(regs->gpr, 0, sizeof(regs->gpr)); 769 regs->ctr = 0; 770 regs->link = 0; 771 regs->xer = 0; 772 regs->ccr = 0; 773 regs->gpr[1] = sp; 774 775 /* 776 * We have just cleared all the nonvolatile GPRs, so make 777 * FULL_REGS(regs) return true. This is necessary to allow 778 * ptrace to examine the thread immediately after exec. 779 */ 780 regs->trap &= ~1UL; 781 782 #ifdef CONFIG_PPC32 783 regs->mq = 0; 784 regs->nip = start; 785 regs->msr = MSR_USER; 786 #else 787 if (!test_thread_flag(TIF_32BIT)) { 788 unsigned long entry, toc; 789 790 /* start is a relocated pointer to the function descriptor for 791 * the elf _start routine. The first entry in the function 792 * descriptor is the entry address of _start and the second 793 * entry is the TOC value we need to use. 794 */ 795 __get_user(entry, (unsigned long __user *)start); 796 __get_user(toc, (unsigned long __user *)start+1); 797 798 /* Check whether the e_entry function descriptor entries 799 * need to be relocated before we can use them. 800 */ 801 if (load_addr != 0) { 802 entry += load_addr; 803 toc += load_addr; 804 } 805 regs->nip = entry; 806 regs->gpr[2] = toc; 807 regs->msr = MSR_USER64; 808 } else { 809 regs->nip = start; 810 regs->gpr[2] = 0; 811 regs->msr = MSR_USER32; 812 } 813 #endif 814 815 discard_lazy_cpu_state(); 816 #ifdef CONFIG_VSX 817 current->thread.used_vsr = 0; 818 #endif 819 memset(current->thread.fpr, 0, sizeof(current->thread.fpr)); 820 current->thread.fpscr.val = 0; 821 #ifdef CONFIG_ALTIVEC 822 memset(current->thread.vr, 0, sizeof(current->thread.vr)); 823 memset(¤t->thread.vscr, 0, sizeof(current->thread.vscr)); 824 current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */ 825 current->thread.vrsave = 0; 826 current->thread.used_vr = 0; 827 #endif /* CONFIG_ALTIVEC */ 828 #ifdef CONFIG_SPE 829 memset(current->thread.evr, 0, sizeof(current->thread.evr)); 830 current->thread.acc = 0; 831 current->thread.spefscr = 0; 832 current->thread.used_spe = 0; 833 #endif /* CONFIG_SPE */ 834 } 835 836 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \ 837 | PR_FP_EXC_RES | PR_FP_EXC_INV) 838 839 int set_fpexc_mode(struct task_struct *tsk, unsigned int val) 840 { 841 struct pt_regs *regs = tsk->thread.regs; 842 843 /* This is a bit hairy. If we are an SPE enabled processor 844 * (have embedded fp) we store the IEEE exception enable flags in 845 * fpexc_mode. fpexc_mode is also used for setting FP exception 846 * mode (asyn, precise, disabled) for 'Classic' FP. */ 847 if (val & PR_FP_EXC_SW_ENABLE) { 848 #ifdef CONFIG_SPE 849 if (cpu_has_feature(CPU_FTR_SPE)) { 850 tsk->thread.fpexc_mode = val & 851 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT); 852 return 0; 853 } else { 854 return -EINVAL; 855 } 856 #else 857 return -EINVAL; 858 #endif 859 } 860 861 /* on a CONFIG_SPE this does not hurt us. The bits that 862 * __pack_fe01 use do not overlap with bits used for 863 * PR_FP_EXC_SW_ENABLE. Additionally, the MSR[FE0,FE1] bits 864 * on CONFIG_SPE implementations are reserved so writing to 865 * them does not change anything */ 866 if (val > PR_FP_EXC_PRECISE) 867 return -EINVAL; 868 tsk->thread.fpexc_mode = __pack_fe01(val); 869 if (regs != NULL && (regs->msr & MSR_FP) != 0) 870 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1)) 871 | tsk->thread.fpexc_mode; 872 return 0; 873 } 874 875 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr) 876 { 877 unsigned int val; 878 879 if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE) 880 #ifdef CONFIG_SPE 881 if (cpu_has_feature(CPU_FTR_SPE)) 882 val = tsk->thread.fpexc_mode; 883 else 884 return -EINVAL; 885 #else 886 return -EINVAL; 887 #endif 888 else 889 val = __unpack_fe01(tsk->thread.fpexc_mode); 890 return put_user(val, (unsigned int __user *) adr); 891 } 892 893 int set_endian(struct task_struct *tsk, unsigned int val) 894 { 895 struct pt_regs *regs = tsk->thread.regs; 896 897 if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) || 898 (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE))) 899 return -EINVAL; 900 901 if (regs == NULL) 902 return -EINVAL; 903 904 if (val == PR_ENDIAN_BIG) 905 regs->msr &= ~MSR_LE; 906 else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE) 907 regs->msr |= MSR_LE; 908 else 909 return -EINVAL; 910 911 return 0; 912 } 913 914 int get_endian(struct task_struct *tsk, unsigned long adr) 915 { 916 struct pt_regs *regs = tsk->thread.regs; 917 unsigned int val; 918 919 if (!cpu_has_feature(CPU_FTR_PPC_LE) && 920 !cpu_has_feature(CPU_FTR_REAL_LE)) 921 return -EINVAL; 922 923 if (regs == NULL) 924 return -EINVAL; 925 926 if (regs->msr & MSR_LE) { 927 if (cpu_has_feature(CPU_FTR_REAL_LE)) 928 val = PR_ENDIAN_LITTLE; 929 else 930 val = PR_ENDIAN_PPC_LITTLE; 931 } else 932 val = PR_ENDIAN_BIG; 933 934 return put_user(val, (unsigned int __user *)adr); 935 } 936 937 int set_unalign_ctl(struct task_struct *tsk, unsigned int val) 938 { 939 tsk->thread.align_ctl = val; 940 return 0; 941 } 942 943 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr) 944 { 945 return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr); 946 } 947 948 #define TRUNC_PTR(x) ((typeof(x))(((unsigned long)(x)) & 0xffffffff)) 949 950 int sys_clone(unsigned long clone_flags, unsigned long usp, 951 int __user *parent_tidp, void __user *child_threadptr, 952 int __user *child_tidp, int p6, 953 struct pt_regs *regs) 954 { 955 CHECK_FULL_REGS(regs); 956 if (usp == 0) 957 usp = regs->gpr[1]; /* stack pointer for child */ 958 #ifdef CONFIG_PPC64 959 if (test_thread_flag(TIF_32BIT)) { 960 parent_tidp = TRUNC_PTR(parent_tidp); 961 child_tidp = TRUNC_PTR(child_tidp); 962 } 963 #endif 964 return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp); 965 } 966 967 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3, 968 unsigned long p4, unsigned long p5, unsigned long p6, 969 struct pt_regs *regs) 970 { 971 CHECK_FULL_REGS(regs); 972 return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL); 973 } 974 975 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3, 976 unsigned long p4, unsigned long p5, unsigned long p6, 977 struct pt_regs *regs) 978 { 979 CHECK_FULL_REGS(regs); 980 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1], 981 regs, 0, NULL, NULL); 982 } 983 984 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2, 985 unsigned long a3, unsigned long a4, unsigned long a5, 986 struct pt_regs *regs) 987 { 988 int error; 989 char *filename; 990 991 filename = getname((char __user *) a0); 992 error = PTR_ERR(filename); 993 if (IS_ERR(filename)) 994 goto out; 995 flush_fp_to_thread(current); 996 flush_altivec_to_thread(current); 997 flush_spe_to_thread(current); 998 error = do_execve(filename, (char __user * __user *) a1, 999 (char __user * __user *) a2, regs); 1000 putname(filename); 1001 out: 1002 return error; 1003 } 1004 1005 #ifdef CONFIG_IRQSTACKS 1006 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, 1007 unsigned long nbytes) 1008 { 1009 unsigned long stack_page; 1010 unsigned long cpu = task_cpu(p); 1011 1012 /* 1013 * Avoid crashing if the stack has overflowed and corrupted 1014 * task_cpu(p), which is in the thread_info struct. 1015 */ 1016 if (cpu < NR_CPUS && cpu_possible(cpu)) { 1017 stack_page = (unsigned long) hardirq_ctx[cpu]; 1018 if (sp >= stack_page + sizeof(struct thread_struct) 1019 && sp <= stack_page + THREAD_SIZE - nbytes) 1020 return 1; 1021 1022 stack_page = (unsigned long) softirq_ctx[cpu]; 1023 if (sp >= stack_page + sizeof(struct thread_struct) 1024 && sp <= stack_page + THREAD_SIZE - nbytes) 1025 return 1; 1026 } 1027 return 0; 1028 } 1029 1030 #else 1031 #define valid_irq_stack(sp, p, nb) 0 1032 #endif /* CONFIG_IRQSTACKS */ 1033 1034 int validate_sp(unsigned long sp, struct task_struct *p, 1035 unsigned long nbytes) 1036 { 1037 unsigned long stack_page = (unsigned long)task_stack_page(p); 1038 1039 if (sp >= stack_page + sizeof(struct thread_struct) 1040 && sp <= stack_page + THREAD_SIZE - nbytes) 1041 return 1; 1042 1043 return valid_irq_stack(sp, p, nbytes); 1044 } 1045 1046 EXPORT_SYMBOL(validate_sp); 1047 1048 unsigned long get_wchan(struct task_struct *p) 1049 { 1050 unsigned long ip, sp; 1051 int count = 0; 1052 1053 if (!p || p == current || p->state == TASK_RUNNING) 1054 return 0; 1055 1056 sp = p->thread.ksp; 1057 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) 1058 return 0; 1059 1060 do { 1061 sp = *(unsigned long *)sp; 1062 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) 1063 return 0; 1064 if (count > 0) { 1065 ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE]; 1066 if (!in_sched_functions(ip)) 1067 return ip; 1068 } 1069 } while (count++ < 16); 1070 return 0; 1071 } 1072 1073 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; 1074 1075 void show_stack(struct task_struct *tsk, unsigned long *stack) 1076 { 1077 unsigned long sp, ip, lr, newsp; 1078 int count = 0; 1079 int firstframe = 1; 1080 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1081 int curr_frame = current->curr_ret_stack; 1082 extern void return_to_handler(void); 1083 unsigned long rth = (unsigned long)return_to_handler; 1084 unsigned long mrth = -1; 1085 #ifdef CONFIG_PPC64 1086 extern void mod_return_to_handler(void); 1087 rth = *(unsigned long *)rth; 1088 mrth = (unsigned long)mod_return_to_handler; 1089 mrth = *(unsigned long *)mrth; 1090 #endif 1091 #endif 1092 1093 sp = (unsigned long) stack; 1094 if (tsk == NULL) 1095 tsk = current; 1096 if (sp == 0) { 1097 if (tsk == current) 1098 asm("mr %0,1" : "=r" (sp)); 1099 else 1100 sp = tsk->thread.ksp; 1101 } 1102 1103 lr = 0; 1104 printk("Call Trace:\n"); 1105 do { 1106 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) 1107 return; 1108 1109 stack = (unsigned long *) sp; 1110 newsp = stack[0]; 1111 ip = stack[STACK_FRAME_LR_SAVE]; 1112 if (!firstframe || ip != lr) { 1113 printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip); 1114 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1115 if ((ip == rth || ip == mrth) && curr_frame >= 0) { 1116 printk(" (%pS)", 1117 (void *)current->ret_stack[curr_frame].ret); 1118 curr_frame--; 1119 } 1120 #endif 1121 if (firstframe) 1122 printk(" (unreliable)"); 1123 printk("\n"); 1124 } 1125 firstframe = 0; 1126 1127 /* 1128 * See if this is an exception frame. 1129 * We look for the "regshere" marker in the current frame. 1130 */ 1131 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE) 1132 && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { 1133 struct pt_regs *regs = (struct pt_regs *) 1134 (sp + STACK_FRAME_OVERHEAD); 1135 lr = regs->link; 1136 printk("--- Exception: %lx at %pS\n LR = %pS\n", 1137 regs->trap, (void *)regs->nip, (void *)lr); 1138 firstframe = 1; 1139 } 1140 1141 sp = newsp; 1142 } while (count++ < kstack_depth_to_print); 1143 } 1144 1145 void dump_stack(void) 1146 { 1147 show_stack(current, NULL); 1148 } 1149 EXPORT_SYMBOL(dump_stack); 1150 1151 #ifdef CONFIG_PPC64 1152 void ppc64_runlatch_on(void) 1153 { 1154 unsigned long ctrl; 1155 1156 if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) { 1157 HMT_medium(); 1158 1159 ctrl = mfspr(SPRN_CTRLF); 1160 ctrl |= CTRL_RUNLATCH; 1161 mtspr(SPRN_CTRLT, ctrl); 1162 1163 set_thread_flag(TIF_RUNLATCH); 1164 } 1165 } 1166 1167 void ppc64_runlatch_off(void) 1168 { 1169 unsigned long ctrl; 1170 1171 if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) { 1172 HMT_medium(); 1173 1174 clear_thread_flag(TIF_RUNLATCH); 1175 1176 ctrl = mfspr(SPRN_CTRLF); 1177 ctrl &= ~CTRL_RUNLATCH; 1178 mtspr(SPRN_CTRLT, ctrl); 1179 } 1180 } 1181 #endif 1182 1183 #if THREAD_SHIFT < PAGE_SHIFT 1184 1185 static struct kmem_cache *thread_info_cache; 1186 1187 struct thread_info *alloc_thread_info(struct task_struct *tsk) 1188 { 1189 struct thread_info *ti; 1190 1191 ti = kmem_cache_alloc(thread_info_cache, GFP_KERNEL); 1192 if (unlikely(ti == NULL)) 1193 return NULL; 1194 #ifdef CONFIG_DEBUG_STACK_USAGE 1195 memset(ti, 0, THREAD_SIZE); 1196 #endif 1197 return ti; 1198 } 1199 1200 void free_thread_info(struct thread_info *ti) 1201 { 1202 kmem_cache_free(thread_info_cache, ti); 1203 } 1204 1205 void thread_info_cache_init(void) 1206 { 1207 thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE, 1208 THREAD_SIZE, 0, NULL); 1209 BUG_ON(thread_info_cache == NULL); 1210 } 1211 1212 #endif /* THREAD_SHIFT < PAGE_SHIFT */ 1213 1214 unsigned long arch_align_stack(unsigned long sp) 1215 { 1216 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 1217 sp -= get_random_int() & ~PAGE_MASK; 1218 return sp & ~0xf; 1219 } 1220 1221 static inline unsigned long brk_rnd(void) 1222 { 1223 unsigned long rnd = 0; 1224 1225 /* 8MB for 32bit, 1GB for 64bit */ 1226 if (is_32bit_task()) 1227 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT))); 1228 else 1229 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT))); 1230 1231 return rnd << PAGE_SHIFT; 1232 } 1233 1234 unsigned long arch_randomize_brk(struct mm_struct *mm) 1235 { 1236 unsigned long base = mm->brk; 1237 unsigned long ret; 1238 1239 #ifdef CONFIG_PPC_STD_MMU_64 1240 /* 1241 * If we are using 1TB segments and we are allowed to randomise 1242 * the heap, we can put it above 1TB so it is backed by a 1TB 1243 * segment. Otherwise the heap will be in the bottom 1TB 1244 * which always uses 256MB segments and this may result in a 1245 * performance penalty. 1246 */ 1247 if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T)) 1248 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T); 1249 #endif 1250 1251 ret = PAGE_ALIGN(base + brk_rnd()); 1252 1253 if (ret < mm->brk) 1254 return mm->brk; 1255 1256 return ret; 1257 } 1258 1259 unsigned long randomize_et_dyn(unsigned long base) 1260 { 1261 unsigned long ret = PAGE_ALIGN(base + brk_rnd()); 1262 1263 if (ret < base) 1264 return base; 1265 1266 return ret; 1267 } 1268