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 #ifdef CONFIG_PPC_47x 375 isync(); 376 #endif 377 #elif defined(CONFIG_PPC_BOOK3S) 378 mtspr(SPRN_DABR, dabr); 379 #endif 380 381 382 return 0; 383 } 384 385 #ifdef CONFIG_PPC64 386 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array); 387 #endif 388 389 struct task_struct *__switch_to(struct task_struct *prev, 390 struct task_struct *new) 391 { 392 struct thread_struct *new_thread, *old_thread; 393 unsigned long flags; 394 struct task_struct *last; 395 396 #ifdef CONFIG_SMP 397 /* avoid complexity of lazy save/restore of fpu 398 * by just saving it every time we switch out if 399 * this task used the fpu during the last quantum. 400 * 401 * If it tries to use the fpu again, it'll trap and 402 * reload its fp regs. So we don't have to do a restore 403 * every switch, just a save. 404 * -- Cort 405 */ 406 if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP)) 407 giveup_fpu(prev); 408 #ifdef CONFIG_ALTIVEC 409 /* 410 * If the previous thread used altivec in the last quantum 411 * (thus changing altivec regs) then save them. 412 * We used to check the VRSAVE register but not all apps 413 * set it, so we don't rely on it now (and in fact we need 414 * to save & restore VSCR even if VRSAVE == 0). -- paulus 415 * 416 * On SMP we always save/restore altivec regs just to avoid the 417 * complexity of changing processors. 418 * -- Cort 419 */ 420 if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC)) 421 giveup_altivec(prev); 422 #endif /* CONFIG_ALTIVEC */ 423 #ifdef CONFIG_VSX 424 if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX)) 425 /* VMX and FPU registers are already save here */ 426 __giveup_vsx(prev); 427 #endif /* CONFIG_VSX */ 428 #ifdef CONFIG_SPE 429 /* 430 * If the previous thread used spe in the last quantum 431 * (thus changing spe regs) then save them. 432 * 433 * On SMP we always save/restore spe regs just to avoid the 434 * complexity of changing processors. 435 */ 436 if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE))) 437 giveup_spe(prev); 438 #endif /* CONFIG_SPE */ 439 440 #else /* CONFIG_SMP */ 441 #ifdef CONFIG_ALTIVEC 442 /* Avoid the trap. On smp this this never happens since 443 * we don't set last_task_used_altivec -- Cort 444 */ 445 if (new->thread.regs && last_task_used_altivec == new) 446 new->thread.regs->msr |= MSR_VEC; 447 #endif /* CONFIG_ALTIVEC */ 448 #ifdef CONFIG_VSX 449 if (new->thread.regs && last_task_used_vsx == new) 450 new->thread.regs->msr |= MSR_VSX; 451 #endif /* CONFIG_VSX */ 452 #ifdef CONFIG_SPE 453 /* Avoid the trap. On smp this this never happens since 454 * we don't set last_task_used_spe 455 */ 456 if (new->thread.regs && last_task_used_spe == new) 457 new->thread.regs->msr |= MSR_SPE; 458 #endif /* CONFIG_SPE */ 459 460 #endif /* CONFIG_SMP */ 461 462 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 463 switch_booke_debug_regs(&new->thread); 464 #else 465 if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) 466 set_dabr(new->thread.dabr); 467 #endif 468 469 470 new_thread = &new->thread; 471 old_thread = ¤t->thread; 472 473 #ifdef CONFIG_PPC64 474 /* 475 * Collect processor utilization data per process 476 */ 477 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 478 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 479 long unsigned start_tb, current_tb; 480 start_tb = old_thread->start_tb; 481 cu->current_tb = current_tb = mfspr(SPRN_PURR); 482 old_thread->accum_tb += (current_tb - start_tb); 483 new_thread->start_tb = current_tb; 484 } 485 #endif 486 487 local_irq_save(flags); 488 489 account_system_vtime(current); 490 account_process_vtime(current); 491 calculate_steal_time(); 492 493 /* 494 * We can't take a PMU exception inside _switch() since there is a 495 * window where the kernel stack SLB and the kernel stack are out 496 * of sync. Hard disable here. 497 */ 498 hard_irq_disable(); 499 last = _switch(old_thread, new_thread); 500 501 local_irq_restore(flags); 502 503 return last; 504 } 505 506 static int instructions_to_print = 16; 507 508 static void show_instructions(struct pt_regs *regs) 509 { 510 int i; 511 unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 * 512 sizeof(int)); 513 514 printk("Instruction dump:"); 515 516 for (i = 0; i < instructions_to_print; i++) { 517 int instr; 518 519 if (!(i % 8)) 520 printk("\n"); 521 522 #if !defined(CONFIG_BOOKE) 523 /* If executing with the IMMU off, adjust pc rather 524 * than print XXXXXXXX. 525 */ 526 if (!(regs->msr & MSR_IR)) 527 pc = (unsigned long)phys_to_virt(pc); 528 #endif 529 530 /* We use __get_user here *only* to avoid an OOPS on a 531 * bad address because the pc *should* only be a 532 * kernel address. 533 */ 534 if (!__kernel_text_address(pc) || 535 __get_user(instr, (unsigned int __user *)pc)) { 536 printk("XXXXXXXX "); 537 } else { 538 if (regs->nip == pc) 539 printk("<%08x> ", instr); 540 else 541 printk("%08x ", instr); 542 } 543 544 pc += sizeof(int); 545 } 546 547 printk("\n"); 548 } 549 550 static struct regbit { 551 unsigned long bit; 552 const char *name; 553 } msr_bits[] = { 554 {MSR_EE, "EE"}, 555 {MSR_PR, "PR"}, 556 {MSR_FP, "FP"}, 557 {MSR_VEC, "VEC"}, 558 {MSR_VSX, "VSX"}, 559 {MSR_ME, "ME"}, 560 {MSR_CE, "CE"}, 561 {MSR_DE, "DE"}, 562 {MSR_IR, "IR"}, 563 {MSR_DR, "DR"}, 564 {0, NULL} 565 }; 566 567 static void printbits(unsigned long val, struct regbit *bits) 568 { 569 const char *sep = ""; 570 571 printk("<"); 572 for (; bits->bit; ++bits) 573 if (val & bits->bit) { 574 printk("%s%s", sep, bits->name); 575 sep = ","; 576 } 577 printk(">"); 578 } 579 580 #ifdef CONFIG_PPC64 581 #define REG "%016lx" 582 #define REGS_PER_LINE 4 583 #define LAST_VOLATILE 13 584 #else 585 #define REG "%08lx" 586 #define REGS_PER_LINE 8 587 #define LAST_VOLATILE 12 588 #endif 589 590 void show_regs(struct pt_regs * regs) 591 { 592 int i, trap; 593 594 printk("NIP: "REG" LR: "REG" CTR: "REG"\n", 595 regs->nip, regs->link, regs->ctr); 596 printk("REGS: %p TRAP: %04lx %s (%s)\n", 597 regs, regs->trap, print_tainted(), init_utsname()->release); 598 printk("MSR: "REG" ", regs->msr); 599 printbits(regs->msr, msr_bits); 600 printk(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); 601 trap = TRAP(regs); 602 if (trap == 0x300 || trap == 0x600) 603 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 604 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr); 605 #else 606 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr); 607 #endif 608 printk("TASK = %p[%d] '%s' THREAD: %p", 609 current, task_pid_nr(current), current->comm, task_thread_info(current)); 610 611 #ifdef CONFIG_SMP 612 printk(" CPU: %d", raw_smp_processor_id()); 613 #endif /* CONFIG_SMP */ 614 615 for (i = 0; i < 32; i++) { 616 if ((i % REGS_PER_LINE) == 0) 617 printk("\nGPR%02d: ", i); 618 printk(REG " ", regs->gpr[i]); 619 if (i == LAST_VOLATILE && !FULL_REGS(regs)) 620 break; 621 } 622 printk("\n"); 623 #ifdef CONFIG_KALLSYMS 624 /* 625 * Lookup NIP late so we have the best change of getting the 626 * above info out without failing 627 */ 628 printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip); 629 printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link); 630 #endif 631 show_stack(current, (unsigned long *) regs->gpr[1]); 632 if (!user_mode(regs)) 633 show_instructions(regs); 634 } 635 636 void exit_thread(void) 637 { 638 discard_lazy_cpu_state(); 639 } 640 641 void flush_thread(void) 642 { 643 discard_lazy_cpu_state(); 644 645 set_debug_reg_defaults(¤t->thread); 646 } 647 648 void 649 release_thread(struct task_struct *t) 650 { 651 } 652 653 /* 654 * This gets called before we allocate a new thread and copy 655 * the current task into it. 656 */ 657 void prepare_to_copy(struct task_struct *tsk) 658 { 659 flush_fp_to_thread(current); 660 flush_altivec_to_thread(current); 661 flush_vsx_to_thread(current); 662 flush_spe_to_thread(current); 663 } 664 665 /* 666 * Copy a thread.. 667 */ 668 int copy_thread(unsigned long clone_flags, unsigned long usp, 669 unsigned long unused, struct task_struct *p, 670 struct pt_regs *regs) 671 { 672 struct pt_regs *childregs, *kregs; 673 extern void ret_from_fork(void); 674 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; 675 676 CHECK_FULL_REGS(regs); 677 /* Copy registers */ 678 sp -= sizeof(struct pt_regs); 679 childregs = (struct pt_regs *) sp; 680 *childregs = *regs; 681 if ((childregs->msr & MSR_PR) == 0) { 682 /* for kernel thread, set `current' and stackptr in new task */ 683 childregs->gpr[1] = sp + sizeof(struct pt_regs); 684 #ifdef CONFIG_PPC32 685 childregs->gpr[2] = (unsigned long) p; 686 #else 687 clear_tsk_thread_flag(p, TIF_32BIT); 688 #endif 689 p->thread.regs = NULL; /* no user register state */ 690 } else { 691 childregs->gpr[1] = usp; 692 p->thread.regs = childregs; 693 if (clone_flags & CLONE_SETTLS) { 694 #ifdef CONFIG_PPC64 695 if (!test_thread_flag(TIF_32BIT)) 696 childregs->gpr[13] = childregs->gpr[6]; 697 else 698 #endif 699 childregs->gpr[2] = childregs->gpr[6]; 700 } 701 } 702 childregs->gpr[3] = 0; /* Result from fork() */ 703 sp -= STACK_FRAME_OVERHEAD; 704 705 /* 706 * The way this works is that at some point in the future 707 * some task will call _switch to switch to the new task. 708 * That will pop off the stack frame created below and start 709 * the new task running at ret_from_fork. The new task will 710 * do some house keeping and then return from the fork or clone 711 * system call, using the stack frame created above. 712 */ 713 sp -= sizeof(struct pt_regs); 714 kregs = (struct pt_regs *) sp; 715 sp -= STACK_FRAME_OVERHEAD; 716 p->thread.ksp = sp; 717 p->thread.ksp_limit = (unsigned long)task_stack_page(p) + 718 _ALIGN_UP(sizeof(struct thread_info), 16); 719 720 #ifdef CONFIG_PPC_STD_MMU_64 721 if (cpu_has_feature(CPU_FTR_SLB)) { 722 unsigned long sp_vsid; 723 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp; 724 725 if (cpu_has_feature(CPU_FTR_1T_SEGMENT)) 726 sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T) 727 << SLB_VSID_SHIFT_1T; 728 else 729 sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M) 730 << SLB_VSID_SHIFT; 731 sp_vsid |= SLB_VSID_KERNEL | llp; 732 p->thread.ksp_vsid = sp_vsid; 733 } 734 #endif /* CONFIG_PPC_STD_MMU_64 */ 735 736 /* 737 * The PPC64 ABI makes use of a TOC to contain function 738 * pointers. The function (ret_from_except) is actually a pointer 739 * to the TOC entry. The first entry is a pointer to the actual 740 * function. 741 */ 742 #ifdef CONFIG_PPC64 743 kregs->nip = *((unsigned long *)ret_from_fork); 744 #else 745 kregs->nip = (unsigned long)ret_from_fork; 746 #endif 747 748 return 0; 749 } 750 751 /* 752 * Set up a thread for executing a new program 753 */ 754 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) 755 { 756 #ifdef CONFIG_PPC64 757 unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */ 758 #endif 759 760 set_fs(USER_DS); 761 762 /* 763 * If we exec out of a kernel thread then thread.regs will not be 764 * set. Do it now. 765 */ 766 if (!current->thread.regs) { 767 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE; 768 current->thread.regs = regs - 1; 769 } 770 771 memset(regs->gpr, 0, sizeof(regs->gpr)); 772 regs->ctr = 0; 773 regs->link = 0; 774 regs->xer = 0; 775 regs->ccr = 0; 776 regs->gpr[1] = sp; 777 778 /* 779 * We have just cleared all the nonvolatile GPRs, so make 780 * FULL_REGS(regs) return true. This is necessary to allow 781 * ptrace to examine the thread immediately after exec. 782 */ 783 regs->trap &= ~1UL; 784 785 #ifdef CONFIG_PPC32 786 regs->mq = 0; 787 regs->nip = start; 788 regs->msr = MSR_USER; 789 #else 790 if (!test_thread_flag(TIF_32BIT)) { 791 unsigned long entry, toc; 792 793 /* start is a relocated pointer to the function descriptor for 794 * the elf _start routine. The first entry in the function 795 * descriptor is the entry address of _start and the second 796 * entry is the TOC value we need to use. 797 */ 798 __get_user(entry, (unsigned long __user *)start); 799 __get_user(toc, (unsigned long __user *)start+1); 800 801 /* Check whether the e_entry function descriptor entries 802 * need to be relocated before we can use them. 803 */ 804 if (load_addr != 0) { 805 entry += load_addr; 806 toc += load_addr; 807 } 808 regs->nip = entry; 809 regs->gpr[2] = toc; 810 regs->msr = MSR_USER64; 811 } else { 812 regs->nip = start; 813 regs->gpr[2] = 0; 814 regs->msr = MSR_USER32; 815 } 816 #endif 817 818 discard_lazy_cpu_state(); 819 #ifdef CONFIG_VSX 820 current->thread.used_vsr = 0; 821 #endif 822 memset(current->thread.fpr, 0, sizeof(current->thread.fpr)); 823 current->thread.fpscr.val = 0; 824 #ifdef CONFIG_ALTIVEC 825 memset(current->thread.vr, 0, sizeof(current->thread.vr)); 826 memset(¤t->thread.vscr, 0, sizeof(current->thread.vscr)); 827 current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */ 828 current->thread.vrsave = 0; 829 current->thread.used_vr = 0; 830 #endif /* CONFIG_ALTIVEC */ 831 #ifdef CONFIG_SPE 832 memset(current->thread.evr, 0, sizeof(current->thread.evr)); 833 current->thread.acc = 0; 834 current->thread.spefscr = 0; 835 current->thread.used_spe = 0; 836 #endif /* CONFIG_SPE */ 837 } 838 839 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \ 840 | PR_FP_EXC_RES | PR_FP_EXC_INV) 841 842 int set_fpexc_mode(struct task_struct *tsk, unsigned int val) 843 { 844 struct pt_regs *regs = tsk->thread.regs; 845 846 /* This is a bit hairy. If we are an SPE enabled processor 847 * (have embedded fp) we store the IEEE exception enable flags in 848 * fpexc_mode. fpexc_mode is also used for setting FP exception 849 * mode (asyn, precise, disabled) for 'Classic' FP. */ 850 if (val & PR_FP_EXC_SW_ENABLE) { 851 #ifdef CONFIG_SPE 852 if (cpu_has_feature(CPU_FTR_SPE)) { 853 tsk->thread.fpexc_mode = val & 854 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT); 855 return 0; 856 } else { 857 return -EINVAL; 858 } 859 #else 860 return -EINVAL; 861 #endif 862 } 863 864 /* on a CONFIG_SPE this does not hurt us. The bits that 865 * __pack_fe01 use do not overlap with bits used for 866 * PR_FP_EXC_SW_ENABLE. Additionally, the MSR[FE0,FE1] bits 867 * on CONFIG_SPE implementations are reserved so writing to 868 * them does not change anything */ 869 if (val > PR_FP_EXC_PRECISE) 870 return -EINVAL; 871 tsk->thread.fpexc_mode = __pack_fe01(val); 872 if (regs != NULL && (regs->msr & MSR_FP) != 0) 873 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1)) 874 | tsk->thread.fpexc_mode; 875 return 0; 876 } 877 878 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr) 879 { 880 unsigned int val; 881 882 if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE) 883 #ifdef CONFIG_SPE 884 if (cpu_has_feature(CPU_FTR_SPE)) 885 val = tsk->thread.fpexc_mode; 886 else 887 return -EINVAL; 888 #else 889 return -EINVAL; 890 #endif 891 else 892 val = __unpack_fe01(tsk->thread.fpexc_mode); 893 return put_user(val, (unsigned int __user *) adr); 894 } 895 896 int set_endian(struct task_struct *tsk, unsigned int val) 897 { 898 struct pt_regs *regs = tsk->thread.regs; 899 900 if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) || 901 (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE))) 902 return -EINVAL; 903 904 if (regs == NULL) 905 return -EINVAL; 906 907 if (val == PR_ENDIAN_BIG) 908 regs->msr &= ~MSR_LE; 909 else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE) 910 regs->msr |= MSR_LE; 911 else 912 return -EINVAL; 913 914 return 0; 915 } 916 917 int get_endian(struct task_struct *tsk, unsigned long adr) 918 { 919 struct pt_regs *regs = tsk->thread.regs; 920 unsigned int val; 921 922 if (!cpu_has_feature(CPU_FTR_PPC_LE) && 923 !cpu_has_feature(CPU_FTR_REAL_LE)) 924 return -EINVAL; 925 926 if (regs == NULL) 927 return -EINVAL; 928 929 if (regs->msr & MSR_LE) { 930 if (cpu_has_feature(CPU_FTR_REAL_LE)) 931 val = PR_ENDIAN_LITTLE; 932 else 933 val = PR_ENDIAN_PPC_LITTLE; 934 } else 935 val = PR_ENDIAN_BIG; 936 937 return put_user(val, (unsigned int __user *)adr); 938 } 939 940 int set_unalign_ctl(struct task_struct *tsk, unsigned int val) 941 { 942 tsk->thread.align_ctl = val; 943 return 0; 944 } 945 946 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr) 947 { 948 return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr); 949 } 950 951 #define TRUNC_PTR(x) ((typeof(x))(((unsigned long)(x)) & 0xffffffff)) 952 953 int sys_clone(unsigned long clone_flags, unsigned long usp, 954 int __user *parent_tidp, void __user *child_threadptr, 955 int __user *child_tidp, int p6, 956 struct pt_regs *regs) 957 { 958 CHECK_FULL_REGS(regs); 959 if (usp == 0) 960 usp = regs->gpr[1]; /* stack pointer for child */ 961 #ifdef CONFIG_PPC64 962 if (test_thread_flag(TIF_32BIT)) { 963 parent_tidp = TRUNC_PTR(parent_tidp); 964 child_tidp = TRUNC_PTR(child_tidp); 965 } 966 #endif 967 return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp); 968 } 969 970 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3, 971 unsigned long p4, unsigned long p5, unsigned long p6, 972 struct pt_regs *regs) 973 { 974 CHECK_FULL_REGS(regs); 975 return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL); 976 } 977 978 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3, 979 unsigned long p4, unsigned long p5, unsigned long p6, 980 struct pt_regs *regs) 981 { 982 CHECK_FULL_REGS(regs); 983 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1], 984 regs, 0, NULL, NULL); 985 } 986 987 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2, 988 unsigned long a3, unsigned long a4, unsigned long a5, 989 struct pt_regs *regs) 990 { 991 int error; 992 char *filename; 993 994 filename = getname((char __user *) a0); 995 error = PTR_ERR(filename); 996 if (IS_ERR(filename)) 997 goto out; 998 flush_fp_to_thread(current); 999 flush_altivec_to_thread(current); 1000 flush_spe_to_thread(current); 1001 error = do_execve(filename, (char __user * __user *) a1, 1002 (char __user * __user *) a2, regs); 1003 putname(filename); 1004 out: 1005 return error; 1006 } 1007 1008 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, 1009 unsigned long nbytes) 1010 { 1011 unsigned long stack_page; 1012 unsigned long cpu = task_cpu(p); 1013 1014 /* 1015 * Avoid crashing if the stack has overflowed and corrupted 1016 * task_cpu(p), which is in the thread_info struct. 1017 */ 1018 if (cpu < NR_CPUS && cpu_possible(cpu)) { 1019 stack_page = (unsigned long) hardirq_ctx[cpu]; 1020 if (sp >= stack_page + sizeof(struct thread_struct) 1021 && sp <= stack_page + THREAD_SIZE - nbytes) 1022 return 1; 1023 1024 stack_page = (unsigned long) softirq_ctx[cpu]; 1025 if (sp >= stack_page + sizeof(struct thread_struct) 1026 && sp <= stack_page + THREAD_SIZE - nbytes) 1027 return 1; 1028 } 1029 return 0; 1030 } 1031 1032 int validate_sp(unsigned long sp, struct task_struct *p, 1033 unsigned long nbytes) 1034 { 1035 unsigned long stack_page = (unsigned long)task_stack_page(p); 1036 1037 if (sp >= stack_page + sizeof(struct thread_struct) 1038 && sp <= stack_page + THREAD_SIZE - nbytes) 1039 return 1; 1040 1041 return valid_irq_stack(sp, p, nbytes); 1042 } 1043 1044 EXPORT_SYMBOL(validate_sp); 1045 1046 unsigned long get_wchan(struct task_struct *p) 1047 { 1048 unsigned long ip, sp; 1049 int count = 0; 1050 1051 if (!p || p == current || p->state == TASK_RUNNING) 1052 return 0; 1053 1054 sp = p->thread.ksp; 1055 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) 1056 return 0; 1057 1058 do { 1059 sp = *(unsigned long *)sp; 1060 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) 1061 return 0; 1062 if (count > 0) { 1063 ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE]; 1064 if (!in_sched_functions(ip)) 1065 return ip; 1066 } 1067 } while (count++ < 16); 1068 return 0; 1069 } 1070 1071 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; 1072 1073 void show_stack(struct task_struct *tsk, unsigned long *stack) 1074 { 1075 unsigned long sp, ip, lr, newsp; 1076 int count = 0; 1077 int firstframe = 1; 1078 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1079 int curr_frame = current->curr_ret_stack; 1080 extern void return_to_handler(void); 1081 unsigned long rth = (unsigned long)return_to_handler; 1082 unsigned long mrth = -1; 1083 #ifdef CONFIG_PPC64 1084 extern void mod_return_to_handler(void); 1085 rth = *(unsigned long *)rth; 1086 mrth = (unsigned long)mod_return_to_handler; 1087 mrth = *(unsigned long *)mrth; 1088 #endif 1089 #endif 1090 1091 sp = (unsigned long) stack; 1092 if (tsk == NULL) 1093 tsk = current; 1094 if (sp == 0) { 1095 if (tsk == current) 1096 asm("mr %0,1" : "=r" (sp)); 1097 else 1098 sp = tsk->thread.ksp; 1099 } 1100 1101 lr = 0; 1102 printk("Call Trace:\n"); 1103 do { 1104 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) 1105 return; 1106 1107 stack = (unsigned long *) sp; 1108 newsp = stack[0]; 1109 ip = stack[STACK_FRAME_LR_SAVE]; 1110 if (!firstframe || ip != lr) { 1111 printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip); 1112 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1113 if ((ip == rth || ip == mrth) && curr_frame >= 0) { 1114 printk(" (%pS)", 1115 (void *)current->ret_stack[curr_frame].ret); 1116 curr_frame--; 1117 } 1118 #endif 1119 if (firstframe) 1120 printk(" (unreliable)"); 1121 printk("\n"); 1122 } 1123 firstframe = 0; 1124 1125 /* 1126 * See if this is an exception frame. 1127 * We look for the "regshere" marker in the current frame. 1128 */ 1129 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE) 1130 && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { 1131 struct pt_regs *regs = (struct pt_regs *) 1132 (sp + STACK_FRAME_OVERHEAD); 1133 lr = regs->link; 1134 printk("--- Exception: %lx at %pS\n LR = %pS\n", 1135 regs->trap, (void *)regs->nip, (void *)lr); 1136 firstframe = 1; 1137 } 1138 1139 sp = newsp; 1140 } while (count++ < kstack_depth_to_print); 1141 } 1142 1143 void dump_stack(void) 1144 { 1145 show_stack(current, NULL); 1146 } 1147 EXPORT_SYMBOL(dump_stack); 1148 1149 #ifdef CONFIG_PPC64 1150 void ppc64_runlatch_on(void) 1151 { 1152 unsigned long ctrl; 1153 1154 if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) { 1155 HMT_medium(); 1156 1157 ctrl = mfspr(SPRN_CTRLF); 1158 ctrl |= CTRL_RUNLATCH; 1159 mtspr(SPRN_CTRLT, ctrl); 1160 1161 set_thread_flag(TIF_RUNLATCH); 1162 } 1163 } 1164 1165 void ppc64_runlatch_off(void) 1166 { 1167 unsigned long ctrl; 1168 1169 if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) { 1170 HMT_medium(); 1171 1172 clear_thread_flag(TIF_RUNLATCH); 1173 1174 ctrl = mfspr(SPRN_CTRLF); 1175 ctrl &= ~CTRL_RUNLATCH; 1176 mtspr(SPRN_CTRLT, ctrl); 1177 } 1178 } 1179 #endif 1180 1181 #if THREAD_SHIFT < PAGE_SHIFT 1182 1183 static struct kmem_cache *thread_info_cache; 1184 1185 struct thread_info *alloc_thread_info(struct task_struct *tsk) 1186 { 1187 struct thread_info *ti; 1188 1189 ti = kmem_cache_alloc(thread_info_cache, GFP_KERNEL); 1190 if (unlikely(ti == NULL)) 1191 return NULL; 1192 #ifdef CONFIG_DEBUG_STACK_USAGE 1193 memset(ti, 0, THREAD_SIZE); 1194 #endif 1195 return ti; 1196 } 1197 1198 void free_thread_info(struct thread_info *ti) 1199 { 1200 kmem_cache_free(thread_info_cache, ti); 1201 } 1202 1203 void thread_info_cache_init(void) 1204 { 1205 thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE, 1206 THREAD_SIZE, 0, NULL); 1207 BUG_ON(thread_info_cache == NULL); 1208 } 1209 1210 #endif /* THREAD_SHIFT < PAGE_SHIFT */ 1211 1212 unsigned long arch_align_stack(unsigned long sp) 1213 { 1214 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 1215 sp -= get_random_int() & ~PAGE_MASK; 1216 return sp & ~0xf; 1217 } 1218 1219 static inline unsigned long brk_rnd(void) 1220 { 1221 unsigned long rnd = 0; 1222 1223 /* 8MB for 32bit, 1GB for 64bit */ 1224 if (is_32bit_task()) 1225 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT))); 1226 else 1227 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT))); 1228 1229 return rnd << PAGE_SHIFT; 1230 } 1231 1232 unsigned long arch_randomize_brk(struct mm_struct *mm) 1233 { 1234 unsigned long base = mm->brk; 1235 unsigned long ret; 1236 1237 #ifdef CONFIG_PPC_STD_MMU_64 1238 /* 1239 * If we are using 1TB segments and we are allowed to randomise 1240 * the heap, we can put it above 1TB so it is backed by a 1TB 1241 * segment. Otherwise the heap will be in the bottom 1TB 1242 * which always uses 256MB segments and this may result in a 1243 * performance penalty. 1244 */ 1245 if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T)) 1246 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T); 1247 #endif 1248 1249 ret = PAGE_ALIGN(base + brk_rnd()); 1250 1251 if (ret < mm->brk) 1252 return mm->brk; 1253 1254 return ret; 1255 } 1256 1257 unsigned long randomize_et_dyn(unsigned long base) 1258 { 1259 unsigned long ret = PAGE_ALIGN(base + brk_rnd()); 1260 1261 if (ret < base) 1262 return base; 1263 1264 return ret; 1265 } 1266