| 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/gmap.h> |
| 36 | #include <asm/irq.h> |
| 37 | #include <asm/mmu_context.h> |
| 38 | #include <asm/facility.h> |
| 39 | #include "../kernel/entry.h" |
| 40 | |
| 41 | #define __FAIL_ADDR_MASK -4096L |
| 42 | #define __SUBCODE_MASK 0x0600 |
| 43 | #define __PF_RES_FIELD 0x8000000000000000ULL |
| 44 | |
| 45 | #define VM_FAULT_BADCONTEXT 0x010000 |
| 46 | #define VM_FAULT_BADMAP 0x020000 |
| 47 | #define VM_FAULT_BADACCESS 0x040000 |
| 48 | #define VM_FAULT_SIGNAL 0x080000 |
| 49 | #define VM_FAULT_PFAULT 0x100000 |
| 50 | |
| 51 | static unsigned long store_indication __read_mostly; |
| 52 | |
| 53 | static int __init fault_init(void) |
| 54 | { |
| 55 | if (test_facility(75)) |
| 56 | store_indication = 0xc00; |
| 57 | return 0; |
| 58 | } |
| 59 | early_initcall(fault_init); |
| 60 | |
| 61 | static inline int notify_page_fault(struct pt_regs *regs) |
| 62 | { |
| 63 | int ret = 0; |
| 64 | |
| 65 | /* kprobe_running() needs smp_processor_id() */ |
| 66 | if (kprobes_built_in() && !user_mode(regs)) { |
| 67 | preempt_disable(); |
| 68 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) |
| 69 | ret = 1; |
| 70 | preempt_enable(); |
| 71 | } |
| 72 | return ret; |
| 73 | } |
| 74 | |
| 75 | |
| 76 | /* |
| 77 | * Unlock any spinlocks which will prevent us from getting the |
| 78 | * message out. |
| 79 | */ |
| 80 | void bust_spinlocks(int yes) |
| 81 | { |
| 82 | if (yes) { |
| 83 | oops_in_progress = 1; |
| 84 | } else { |
| 85 | int loglevel_save = console_loglevel; |
| 86 | console_unblank(); |
| 87 | oops_in_progress = 0; |
| 88 | /* |
| 89 | * OK, the message is on the console. Now we call printk() |
| 90 | * without oops_in_progress set so that printk will give klogd |
| 91 | * a poke. Hold onto your hats... |
| 92 | */ |
| 93 | console_loglevel = 15; |
| 94 | printk(" "); |
| 95 | console_loglevel = loglevel_save; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * Returns the address space associated with the fault. |
| 101 | * Returns 0 for kernel space and 1 for user space. |
| 102 | */ |
| 103 | static inline int user_space_fault(struct pt_regs *regs) |
| 104 | { |
| 105 | unsigned long trans_exc_code; |
| 106 | |
| 107 | /* |
| 108 | * The lowest two bits of the translation exception |
| 109 | * identification indicate which paging table was used. |
| 110 | */ |
| 111 | trans_exc_code = regs->int_parm_long & 3; |
| 112 | if (trans_exc_code == 3) /* home space -> kernel */ |
| 113 | return 0; |
| 114 | if (user_mode(regs)) |
| 115 | return 1; |
| 116 | if (trans_exc_code == 2) /* secondary space -> set_fs */ |
| 117 | return current->thread.mm_segment.ar4; |
| 118 | if (current->flags & PF_VCPU) |
| 119 | return 1; |
| 120 | return 0; |
| 121 | } |
| 122 | |
| 123 | static int bad_address(void *p) |
| 124 | { |
| 125 | unsigned long dummy; |
| 126 | |
| 127 | return probe_kernel_address((unsigned long *)p, dummy); |
| 128 | } |
| 129 | |
| 130 | static void dump_pagetable(unsigned long asce, unsigned long address) |
| 131 | { |
| 132 | unsigned long *table = __va(asce & PAGE_MASK); |
| 133 | |
| 134 | pr_alert("AS:%016lx ", asce); |
| 135 | switch (asce & _ASCE_TYPE_MASK) { |
| 136 | case _ASCE_TYPE_REGION1: |
| 137 | table = table + ((address >> 53) & 0x7ff); |
| 138 | if (bad_address(table)) |
| 139 | goto bad; |
| 140 | pr_cont("R1:%016lx ", *table); |
| 141 | if (*table & _REGION_ENTRY_INVALID) |
| 142 | goto out; |
| 143 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); |
| 144 | /* fallthrough */ |
| 145 | case _ASCE_TYPE_REGION2: |
| 146 | table = table + ((address >> 42) & 0x7ff); |
| 147 | if (bad_address(table)) |
| 148 | goto bad; |
| 149 | pr_cont("R2:%016lx ", *table); |
| 150 | if (*table & _REGION_ENTRY_INVALID) |
| 151 | goto out; |
| 152 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); |
| 153 | /* fallthrough */ |
| 154 | case _ASCE_TYPE_REGION3: |
| 155 | table = table + ((address >> 31) & 0x7ff); |
| 156 | if (bad_address(table)) |
| 157 | goto bad; |
| 158 | pr_cont("R3:%016lx ", *table); |
| 159 | if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) |
| 160 | goto out; |
| 161 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); |
| 162 | /* fallthrough */ |
| 163 | case _ASCE_TYPE_SEGMENT: |
| 164 | table = table + ((address >> 20) & 0x7ff); |
| 165 | if (bad_address(table)) |
| 166 | goto bad; |
| 167 | pr_cont("S:%016lx ", *table); |
| 168 | if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) |
| 169 | goto out; |
| 170 | table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); |
| 171 | } |
| 172 | table = table + ((address >> 12) & 0xff); |
| 173 | if (bad_address(table)) |
| 174 | goto bad; |
| 175 | pr_cont("P:%016lx ", *table); |
| 176 | out: |
| 177 | pr_cont("\n"); |
| 178 | return; |
| 179 | bad: |
| 180 | pr_cont("BAD\n"); |
| 181 | } |
| 182 | |
| 183 | static void dump_fault_info(struct pt_regs *regs) |
| 184 | { |
| 185 | unsigned long asce; |
| 186 | |
| 187 | pr_alert("Failing address: %016lx TEID: %016lx\n", |
| 188 | regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); |
| 189 | pr_alert("Fault in "); |
| 190 | switch (regs->int_parm_long & 3) { |
| 191 | case 3: |
| 192 | pr_cont("home space "); |
| 193 | break; |
| 194 | case 2: |
| 195 | pr_cont("secondary space "); |
| 196 | break; |
| 197 | case 1: |
| 198 | pr_cont("access register "); |
| 199 | break; |
| 200 | case 0: |
| 201 | pr_cont("primary space "); |
| 202 | break; |
| 203 | } |
| 204 | pr_cont("mode while using "); |
| 205 | if (!user_space_fault(regs)) { |
| 206 | asce = S390_lowcore.kernel_asce; |
| 207 | pr_cont("kernel "); |
| 208 | } |
| 209 | #ifdef CONFIG_PGSTE |
| 210 | else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { |
| 211 | struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; |
| 212 | asce = gmap->asce; |
| 213 | pr_cont("gmap "); |
| 214 | } |
| 215 | #endif |
| 216 | else { |
| 217 | asce = S390_lowcore.user_asce; |
| 218 | pr_cont("user "); |
| 219 | } |
| 220 | pr_cont("ASCE.\n"); |
| 221 | dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); |
| 222 | } |
| 223 | |
| 224 | int show_unhandled_signals = 1; |
| 225 | |
| 226 | void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault) |
| 227 | { |
| 228 | if ((task_pid_nr(current) > 1) && !show_unhandled_signals) |
| 229 | return; |
| 230 | if (!unhandled_signal(current, signr)) |
| 231 | return; |
| 232 | if (!printk_ratelimit()) |
| 233 | return; |
| 234 | printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ", |
| 235 | regs->int_code & 0xffff, regs->int_code >> 17); |
| 236 | print_vma_addr(KERN_CONT "in ", regs->psw.addr); |
| 237 | printk(KERN_CONT "\n"); |
| 238 | if (is_mm_fault) |
| 239 | dump_fault_info(regs); |
| 240 | show_regs(regs); |
| 241 | } |
| 242 | |
| 243 | /* |
| 244 | * Send SIGSEGV to task. This is an external routine |
| 245 | * to keep the stack usage of do_page_fault small. |
| 246 | */ |
| 247 | static noinline void do_sigsegv(struct pt_regs *regs, int si_code) |
| 248 | { |
| 249 | struct siginfo si; |
| 250 | |
| 251 | report_user_fault(regs, SIGSEGV, 1); |
| 252 | si.si_signo = SIGSEGV; |
| 253 | si.si_code = si_code; |
| 254 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
| 255 | force_sig_info(SIGSEGV, &si, current); |
| 256 | } |
| 257 | |
| 258 | static noinline void do_no_context(struct pt_regs *regs) |
| 259 | { |
| 260 | const struct exception_table_entry *fixup; |
| 261 | |
| 262 | /* Are we prepared to handle this kernel fault? */ |
| 263 | fixup = search_exception_tables(regs->psw.addr); |
| 264 | if (fixup) { |
| 265 | regs->psw.addr = extable_fixup(fixup); |
| 266 | return; |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | * Oops. The kernel tried to access some bad page. We'll have to |
| 271 | * terminate things with extreme prejudice. |
| 272 | */ |
| 273 | if (!user_space_fault(regs)) |
| 274 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" |
| 275 | " in virtual kernel address space\n"); |
| 276 | else |
| 277 | printk(KERN_ALERT "Unable to handle kernel paging request" |
| 278 | " in virtual user address space\n"); |
| 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 */ |