1 /* 2 * S390 version 3 * Copyright IBM Corp. 1999 4 * Author(s): Hartmut Penner (hp@de.ibm.com) 5 * Ulrich Weigand (uweigand@de.ibm.com) 6 * 7 * Derived from "arch/i386/mm/fault.c" 8 * Copyright (C) 1995 Linus Torvalds 9 */ 10 11 #include <linux/kernel_stat.h> 12 #include <linux/perf_event.h> 13 #include <linux/signal.h> 14 #include <linux/sched.h> 15 #include <linux/kernel.h> 16 #include <linux/errno.h> 17 #include <linux/string.h> 18 #include <linux/types.h> 19 #include <linux/ptrace.h> 20 #include <linux/mman.h> 21 #include <linux/mm.h> 22 #include <linux/compat.h> 23 #include <linux/smp.h> 24 #include <linux/kdebug.h> 25 #include <linux/init.h> 26 #include <linux/console.h> 27 #include <linux/module.h> 28 #include <linux/hardirq.h> 29 #include <linux/kprobes.h> 30 #include <linux/uaccess.h> 31 #include <linux/hugetlb.h> 32 #include <asm/asm-offsets.h> 33 #include <asm/diag.h> 34 #include <asm/pgtable.h> 35 #include <asm/irq.h> 36 #include <asm/mmu_context.h> 37 #include <asm/facility.h> 38 #include "../kernel/entry.h" 39 40 #define __FAIL_ADDR_MASK -4096L 41 #define __SUBCODE_MASK 0x0600 42 #define __PF_RES_FIELD 0x8000000000000000ULL 43 44 #define VM_FAULT_BADCONTEXT 0x010000 45 #define VM_FAULT_BADMAP 0x020000 46 #define VM_FAULT_BADACCESS 0x040000 47 #define VM_FAULT_SIGNAL 0x080000 48 #define VM_FAULT_PFAULT 0x100000 49 50 static unsigned long store_indication __read_mostly; 51 52 static int __init fault_init(void) 53 { 54 if (test_facility(75)) 55 store_indication = 0xc00; 56 return 0; 57 } 58 early_initcall(fault_init); 59 60 static inline int notify_page_fault(struct pt_regs *regs) 61 { 62 int ret = 0; 63 64 /* kprobe_running() needs smp_processor_id() */ 65 if (kprobes_built_in() && !user_mode(regs)) { 66 preempt_disable(); 67 if (kprobe_running() && kprobe_fault_handler(regs, 14)) 68 ret = 1; 69 preempt_enable(); 70 } 71 return ret; 72 } 73 74 75 /* 76 * Unlock any spinlocks which will prevent us from getting the 77 * message out. 78 */ 79 void bust_spinlocks(int yes) 80 { 81 if (yes) { 82 oops_in_progress = 1; 83 } else { 84 int loglevel_save = console_loglevel; 85 console_unblank(); 86 oops_in_progress = 0; 87 /* 88 * OK, the message is on the console. Now we call printk() 89 * without oops_in_progress set so that printk will give klogd 90 * a poke. Hold onto your hats... 91 */ 92 console_loglevel = 15; 93 printk(" "); 94 console_loglevel = loglevel_save; 95 } 96 } 97 98 /* 99 * Returns the address space associated with the fault. 100 * Returns 0 for kernel space and 1 for user space. 101 */ 102 static inline int user_space_fault(struct pt_regs *regs) 103 { 104 unsigned long trans_exc_code; 105 106 /* 107 * The lowest two bits of the translation exception 108 * identification indicate which paging table was used. 109 */ 110 trans_exc_code = regs->int_parm_long & 3; 111 if (trans_exc_code == 3) /* home space -> kernel */ 112 return 0; 113 if (user_mode(regs)) 114 return 1; 115 if (trans_exc_code == 2) /* secondary space -> set_fs */ 116 return current->thread.mm_segment.ar4; 117 if (current->flags & PF_VCPU) 118 return 1; 119 return 0; 120 } 121 122 static int bad_address(void *p) 123 { 124 unsigned long dummy; 125 126 return probe_kernel_address((unsigned long *)p, dummy); 127 } 128 129 static void dump_pagetable(unsigned long asce, unsigned long address) 130 { 131 unsigned long *table = __va(asce & PAGE_MASK); 132 133 pr_alert("AS:%016lx ", asce); 134 switch (asce & _ASCE_TYPE_MASK) { 135 case _ASCE_TYPE_REGION1: 136 table = table + ((address >> 53) & 0x7ff); 137 if (bad_address(table)) 138 goto bad; 139 pr_cont("R1:%016lx ", *table); 140 if (*table & _REGION_ENTRY_INVALID) 141 goto out; 142 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 143 /* fallthrough */ 144 case _ASCE_TYPE_REGION2: 145 table = table + ((address >> 42) & 0x7ff); 146 if (bad_address(table)) 147 goto bad; 148 pr_cont("R2:%016lx ", *table); 149 if (*table & _REGION_ENTRY_INVALID) 150 goto out; 151 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 152 /* fallthrough */ 153 case _ASCE_TYPE_REGION3: 154 table = table + ((address >> 31) & 0x7ff); 155 if (bad_address(table)) 156 goto bad; 157 pr_cont("R3:%016lx ", *table); 158 if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) 159 goto out; 160 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 161 /* fallthrough */ 162 case _ASCE_TYPE_SEGMENT: 163 table = table + ((address >> 20) & 0x7ff); 164 if (bad_address(table)) 165 goto bad; 166 pr_cont("S:%016lx ", *table); 167 if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) 168 goto out; 169 table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); 170 } 171 table = table + ((address >> 12) & 0xff); 172 if (bad_address(table)) 173 goto bad; 174 pr_cont("P:%016lx ", *table); 175 out: 176 pr_cont("\n"); 177 return; 178 bad: 179 pr_cont("BAD\n"); 180 } 181 182 static void dump_fault_info(struct pt_regs *regs) 183 { 184 unsigned long asce; 185 186 pr_alert("Fault in "); 187 switch (regs->int_parm_long & 3) { 188 case 3: 189 pr_cont("home space "); 190 break; 191 case 2: 192 pr_cont("secondary space "); 193 break; 194 case 1: 195 pr_cont("access register "); 196 break; 197 case 0: 198 pr_cont("primary space "); 199 break; 200 } 201 pr_cont("mode while using "); 202 if (!user_space_fault(regs)) { 203 asce = S390_lowcore.kernel_asce; 204 pr_cont("kernel "); 205 } 206 #ifdef CONFIG_PGSTE 207 else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { 208 struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; 209 asce = gmap->asce; 210 pr_cont("gmap "); 211 } 212 #endif 213 else { 214 asce = S390_lowcore.user_asce; 215 pr_cont("user "); 216 } 217 pr_cont("ASCE.\n"); 218 dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); 219 } 220 221 static inline void report_user_fault(struct pt_regs *regs, long signr) 222 { 223 if ((task_pid_nr(current) > 1) && !show_unhandled_signals) 224 return; 225 if (!unhandled_signal(current, signr)) 226 return; 227 if (!printk_ratelimit()) 228 return; 229 printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ", 230 regs->int_code & 0xffff, regs->int_code >> 17); 231 print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); 232 printk(KERN_CONT "\n"); 233 printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", 234 regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); 235 dump_fault_info(regs); 236 show_regs(regs); 237 } 238 239 /* 240 * Send SIGSEGV to task. This is an external routine 241 * to keep the stack usage of do_page_fault small. 242 */ 243 static noinline void do_sigsegv(struct pt_regs *regs, int si_code) 244 { 245 struct siginfo si; 246 247 report_user_fault(regs, SIGSEGV); 248 si.si_signo = SIGSEGV; 249 si.si_code = si_code; 250 si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 251 force_sig_info(SIGSEGV, &si, current); 252 } 253 254 static noinline void do_no_context(struct pt_regs *regs) 255 { 256 const struct exception_table_entry *fixup; 257 unsigned long address; 258 259 /* Are we prepared to handle this kernel fault? */ 260 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); 261 if (fixup) { 262 regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; 263 return; 264 } 265 266 /* 267 * Oops. The kernel tried to access some bad page. We'll have to 268 * terminate things with extreme prejudice. 269 */ 270 address = regs->int_parm_long & __FAIL_ADDR_MASK; 271 if (!user_space_fault(regs)) 272 printk(KERN_ALERT "Unable to handle kernel pointer dereference" 273 " in virtual kernel address space\n"); 274 else 275 printk(KERN_ALERT "Unable to handle kernel paging request" 276 " in virtual user address space\n"); 277 printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", 278 regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); 279 dump_fault_info(regs); 280 die(regs, "Oops"); 281 do_exit(SIGKILL); 282 } 283 284 static noinline void do_low_address(struct pt_regs *regs) 285 { 286 /* Low-address protection hit in kernel mode means 287 NULL pointer write access in kernel mode. */ 288 if (regs->psw.mask & PSW_MASK_PSTATE) { 289 /* Low-address protection hit in user mode 'cannot happen'. */ 290 die (regs, "Low-address protection"); 291 do_exit(SIGKILL); 292 } 293 294 do_no_context(regs); 295 } 296 297 static noinline void do_sigbus(struct pt_regs *regs) 298 { 299 struct task_struct *tsk = current; 300 struct siginfo si; 301 302 /* 303 * Send a sigbus, regardless of whether we were in kernel 304 * or user mode. 305 */ 306 si.si_signo = SIGBUS; 307 si.si_errno = 0; 308 si.si_code = BUS_ADRERR; 309 si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 310 force_sig_info(SIGBUS, &si, tsk); 311 } 312 313 static noinline void do_fault_error(struct pt_regs *regs, int fault) 314 { 315 int si_code; 316 317 switch (fault) { 318 case VM_FAULT_BADACCESS: 319 case VM_FAULT_BADMAP: 320 /* Bad memory access. Check if it is kernel or user space. */ 321 if (user_mode(regs)) { 322 /* User mode accesses just cause a SIGSEGV */ 323 si_code = (fault == VM_FAULT_BADMAP) ? 324 SEGV_MAPERR : SEGV_ACCERR; 325 do_sigsegv(regs, si_code); 326 return; 327 } 328 case VM_FAULT_BADCONTEXT: 329 case VM_FAULT_PFAULT: 330 do_no_context(regs); 331 break; 332 case VM_FAULT_SIGNAL: 333 if (!user_mode(regs)) 334 do_no_context(regs); 335 break; 336 default: /* fault & VM_FAULT_ERROR */ 337 if (fault & VM_FAULT_OOM) { 338 if (!user_mode(regs)) 339 do_no_context(regs); 340 else 341 pagefault_out_of_memory(); 342 } else if (fault & VM_FAULT_SIGSEGV) { 343 /* Kernel mode? Handle exceptions or die */ 344 if (!user_mode(regs)) 345 do_no_context(regs); 346 else 347 do_sigsegv(regs, SEGV_MAPERR); 348 } else if (fault & VM_FAULT_SIGBUS) { 349 /* Kernel mode? Handle exceptions or die */ 350 if (!user_mode(regs)) 351 do_no_context(regs); 352 else 353 do_sigbus(regs); 354 } else 355 BUG(); 356 break; 357 } 358 } 359 360 /* 361 * This routine handles page faults. It determines the address, 362 * and the problem, and then passes it off to one of the appropriate 363 * routines. 364 * 365 * interruption code (int_code): 366 * 04 Protection -> Write-Protection (suprression) 367 * 10 Segment translation -> Not present (nullification) 368 * 11 Page translation -> Not present (nullification) 369 * 3b Region third trans. -> Not present (nullification) 370 */ 371 static inline int do_exception(struct pt_regs *regs, int access) 372 { 373 #ifdef CONFIG_PGSTE 374 struct gmap *gmap; 375 #endif 376 struct task_struct *tsk; 377 struct mm_struct *mm; 378 struct vm_area_struct *vma; 379 unsigned long trans_exc_code; 380 unsigned long address; 381 unsigned int flags; 382 int fault; 383 384 tsk = current; 385 /* 386 * The instruction that caused the program check has 387 * been nullified. Don't signal single step via SIGTRAP. 388 */ 389 clear_pt_regs_flag(regs, PIF_PER_TRAP); 390 391 if (notify_page_fault(regs)) 392 return 0; 393 394 mm = tsk->mm; 395 trans_exc_code = regs->int_parm_long; 396 397 /* 398 * Verify that the fault happened in user space, that 399 * we are not in an interrupt and that there is a 400 * user context. 401 */ 402 fault = VM_FAULT_BADCONTEXT; 403 if (unlikely(!user_space_fault(regs) || faulthandler_disabled() || !mm)) 404 goto out; 405 406 address = trans_exc_code & __FAIL_ADDR_MASK; 407 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 408 flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; 409 if (user_mode(regs)) 410 flags |= FAULT_FLAG_USER; 411 if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) 412 flags |= FAULT_FLAG_WRITE; 413 down_read(&mm->mmap_sem); 414 415 #ifdef CONFIG_PGSTE 416 gmap = (current->flags & PF_VCPU) ? 417 (struct gmap *) S390_lowcore.gmap : NULL; 418 if (gmap) { 419 current->thread.gmap_addr = address; 420 address = __gmap_translate(gmap, address); 421 if (address == -EFAULT) { 422 fault = VM_FAULT_BADMAP; 423 goto out_up; 424 } 425 if (gmap->pfault_enabled) 426 flags |= FAULT_FLAG_RETRY_NOWAIT; 427 } 428 #endif 429 430 retry: 431 fault = VM_FAULT_BADMAP; 432 vma = find_vma(mm, address); 433 if (!vma) 434 goto out_up; 435 436 if (unlikely(vma->vm_start > address)) { 437 if (!(vma->vm_flags & VM_GROWSDOWN)) 438 goto out_up; 439 if (expand_stack(vma, address)) 440 goto out_up; 441 } 442 443 /* 444 * Ok, we have a good vm_area for this memory access, so 445 * we can handle it.. 446 */ 447 fault = VM_FAULT_BADACCESS; 448 if (unlikely(!(vma->vm_flags & access))) 449 goto out_up; 450 451 if (is_vm_hugetlb_page(vma)) 452 address &= HPAGE_MASK; 453 /* 454 * If for any reason at all we couldn't handle the fault, 455 * make sure we exit gracefully rather than endlessly redo 456 * the fault. 457 */ 458 fault = handle_mm_fault(mm, vma, address, flags); 459 /* No reason to continue if interrupted by SIGKILL. */ 460 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { 461 fault = VM_FAULT_SIGNAL; 462 goto out; 463 } 464 if (unlikely(fault & VM_FAULT_ERROR)) 465 goto out_up; 466 467 /* 468 * Major/minor page fault accounting is only done on the 469 * initial attempt. If we go through a retry, it is extremely 470 * likely that the page will be found in page cache at that point. 471 */ 472 if (flags & FAULT_FLAG_ALLOW_RETRY) { 473 if (fault & VM_FAULT_MAJOR) { 474 tsk->maj_flt++; 475 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 476 regs, address); 477 } else { 478 tsk->min_flt++; 479 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 480 regs, address); 481 } 482 if (fault & VM_FAULT_RETRY) { 483 #ifdef CONFIG_PGSTE 484 if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { 485 /* FAULT_FLAG_RETRY_NOWAIT has been set, 486 * mmap_sem has not been released */ 487 current->thread.gmap_pfault = 1; 488 fault = VM_FAULT_PFAULT; 489 goto out_up; 490 } 491 #endif 492 /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk 493 * of starvation. */ 494 flags &= ~(FAULT_FLAG_ALLOW_RETRY | 495 FAULT_FLAG_RETRY_NOWAIT); 496 flags |= FAULT_FLAG_TRIED; 497 down_read(&mm->mmap_sem); 498 goto retry; 499 } 500 } 501 #ifdef CONFIG_PGSTE 502 if (gmap) { 503 address = __gmap_link(gmap, current->thread.gmap_addr, 504 address); 505 if (address == -EFAULT) { 506 fault = VM_FAULT_BADMAP; 507 goto out_up; 508 } 509 if (address == -ENOMEM) { 510 fault = VM_FAULT_OOM; 511 goto out_up; 512 } 513 } 514 #endif 515 fault = 0; 516 out_up: 517 up_read(&mm->mmap_sem); 518 out: 519 return fault; 520 } 521 522 void do_protection_exception(struct pt_regs *regs) 523 { 524 unsigned long trans_exc_code; 525 int fault; 526 527 trans_exc_code = regs->int_parm_long; 528 /* 529 * Protection exceptions are suppressing, decrement psw address. 530 * The exception to this rule are aborted transactions, for these 531 * the PSW already points to the correct location. 532 */ 533 if (!(regs->int_code & 0x200)) 534 regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 535 /* 536 * Check for low-address protection. This needs to be treated 537 * as a special case because the translation exception code 538 * field is not guaranteed to contain valid data in this case. 539 */ 540 if (unlikely(!(trans_exc_code & 4))) { 541 do_low_address(regs); 542 return; 543 } 544 fault = do_exception(regs, VM_WRITE); 545 if (unlikely(fault)) 546 do_fault_error(regs, fault); 547 } 548 NOKPROBE_SYMBOL(do_protection_exception); 549 550 void do_dat_exception(struct pt_regs *regs) 551 { 552 int access, fault; 553 554 access = VM_READ | VM_EXEC | VM_WRITE; 555 fault = do_exception(regs, access); 556 if (unlikely(fault)) 557 do_fault_error(regs, fault); 558 } 559 NOKPROBE_SYMBOL(do_dat_exception); 560 561 #ifdef CONFIG_PFAULT 562 /* 563 * 'pfault' pseudo page faults routines. 564 */ 565 static int pfault_disable; 566 567 static int __init nopfault(char *str) 568 { 569 pfault_disable = 1; 570 return 1; 571 } 572 573 __setup("nopfault", nopfault); 574 575 struct pfault_refbk { 576 u16 refdiagc; 577 u16 reffcode; 578 u16 refdwlen; 579 u16 refversn; 580 u64 refgaddr; 581 u64 refselmk; 582 u64 refcmpmk; 583 u64 reserved; 584 } __attribute__ ((packed, aligned(8))); 585 586 int pfault_init(void) 587 { 588 struct pfault_refbk refbk = { 589 .refdiagc = 0x258, 590 .reffcode = 0, 591 .refdwlen = 5, 592 .refversn = 2, 593 .refgaddr = __LC_LPP, 594 .refselmk = 1ULL << 48, 595 .refcmpmk = 1ULL << 48, 596 .reserved = __PF_RES_FIELD }; 597 int rc; 598 599 if (pfault_disable) 600 return -1; 601 diag_stat_inc(DIAG_STAT_X258); 602 asm volatile( 603 " diag %1,%0,0x258\n" 604 "0: j 2f\n" 605 "1: la %0,8\n" 606 "2:\n" 607 EX_TABLE(0b,1b) 608 : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 609 return rc; 610 } 611 612 void pfault_fini(void) 613 { 614 struct pfault_refbk refbk = { 615 .refdiagc = 0x258, 616 .reffcode = 1, 617 .refdwlen = 5, 618 .refversn = 2, 619 }; 620 621 if (pfault_disable) 622 return; 623 diag_stat_inc(DIAG_STAT_X258); 624 asm volatile( 625 " diag %0,0,0x258\n" 626 "0:\n" 627 EX_TABLE(0b,0b) 628 : : "a" (&refbk), "m" (refbk) : "cc"); 629 } 630 631 static DEFINE_SPINLOCK(pfault_lock); 632 static LIST_HEAD(pfault_list); 633 634 static void pfault_interrupt(struct ext_code ext_code, 635 unsigned int param32, unsigned long param64) 636 { 637 struct task_struct *tsk; 638 __u16 subcode; 639 pid_t pid; 640 641 /* 642 * Get the external interruption subcode & pfault 643 * initial/completion signal bit. VM stores this 644 * in the 'cpu address' field associated with the 645 * external interrupt. 646 */ 647 subcode = ext_code.subcode; 648 if ((subcode & 0xff00) != __SUBCODE_MASK) 649 return; 650 inc_irq_stat(IRQEXT_PFL); 651 /* Get the token (= pid of the affected task). */ 652 pid = param64 & LPP_PFAULT_PID_MASK; 653 rcu_read_lock(); 654 tsk = find_task_by_pid_ns(pid, &init_pid_ns); 655 if (tsk) 656 get_task_struct(tsk); 657 rcu_read_unlock(); 658 if (!tsk) 659 return; 660 spin_lock(&pfault_lock); 661 if (subcode & 0x0080) { 662 /* signal bit is set -> a page has been swapped in by VM */ 663 if (tsk->thread.pfault_wait == 1) { 664 /* Initial interrupt was faster than the completion 665 * interrupt. pfault_wait is valid. Set pfault_wait 666 * back to zero and wake up the process. This can 667 * safely be done because the task is still sleeping 668 * and can't produce new pfaults. */ 669 tsk->thread.pfault_wait = 0; 670 list_del(&tsk->thread.list); 671 wake_up_process(tsk); 672 put_task_struct(tsk); 673 } else { 674 /* Completion interrupt was faster than initial 675 * interrupt. Set pfault_wait to -1 so the initial 676 * interrupt doesn't put the task to sleep. 677 * If the task is not running, ignore the completion 678 * interrupt since it must be a leftover of a PFAULT 679 * CANCEL operation which didn't remove all pending 680 * completion interrupts. */ 681 if (tsk->state == TASK_RUNNING) 682 tsk->thread.pfault_wait = -1; 683 } 684 } else { 685 /* signal bit not set -> a real page is missing. */ 686 if (WARN_ON_ONCE(tsk != current)) 687 goto out; 688 if (tsk->thread.pfault_wait == 1) { 689 /* Already on the list with a reference: put to sleep */ 690 __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 691 set_tsk_need_resched(tsk); 692 } else if (tsk->thread.pfault_wait == -1) { 693 /* Completion interrupt was faster than the initial 694 * interrupt (pfault_wait == -1). Set pfault_wait 695 * back to zero and exit. */ 696 tsk->thread.pfault_wait = 0; 697 } else { 698 /* Initial interrupt arrived before completion 699 * interrupt. Let the task sleep. 700 * An extra task reference is needed since a different 701 * cpu may set the task state to TASK_RUNNING again 702 * before the scheduler is reached. */ 703 get_task_struct(tsk); 704 tsk->thread.pfault_wait = 1; 705 list_add(&tsk->thread.list, &pfault_list); 706 __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 707 set_tsk_need_resched(tsk); 708 } 709 } 710 out: 711 spin_unlock(&pfault_lock); 712 put_task_struct(tsk); 713 } 714 715 static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, 716 void *hcpu) 717 { 718 struct thread_struct *thread, *next; 719 struct task_struct *tsk; 720 721 switch (action & ~CPU_TASKS_FROZEN) { 722 case CPU_DEAD: 723 spin_lock_irq(&pfault_lock); 724 list_for_each_entry_safe(thread, next, &pfault_list, list) { 725 thread->pfault_wait = 0; 726 list_del(&thread->list); 727 tsk = container_of(thread, struct task_struct, thread); 728 wake_up_process(tsk); 729 put_task_struct(tsk); 730 } 731 spin_unlock_irq(&pfault_lock); 732 break; 733 default: 734 break; 735 } 736 return NOTIFY_OK; 737 } 738 739 static int __init pfault_irq_init(void) 740 { 741 int rc; 742 743 rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 744 if (rc) 745 goto out_extint; 746 rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 747 if (rc) 748 goto out_pfault; 749 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); 750 hotcpu_notifier(pfault_cpu_notify, 0); 751 return 0; 752 753 out_pfault: 754 unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 755 out_extint: 756 pfault_disable = 1; 757 return rc; 758 } 759 early_initcall(pfault_irq_init); 760 761 #endif /* CONFIG_PFAULT */ 762