Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * arch/s390/mm/fault.c |
| 3 | * |
| 4 | * S390 version |
| 5 | * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation |
| 6 | * Author(s): Hartmut Penner (hp@de.ibm.com) |
| 7 | * Ulrich Weigand (uweigand@de.ibm.com) |
| 8 | * |
| 9 | * Derived from "arch/i386/mm/fault.c" |
| 10 | * Copyright (C) 1995 Linus Torvalds |
| 11 | */ |
| 12 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/smp.h> |
| 23 | #include <linux/smp_lock.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/console.h> |
| 26 | #include <linux/module.h> |
| 27 | #include <linux/hardirq.h> |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 28 | #include <linux/kprobes.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
| 30 | #include <asm/system.h> |
| 31 | #include <asm/uaccess.h> |
| 32 | #include <asm/pgtable.h> |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 33 | #include <asm/kdebug.h> |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 34 | #include <asm/s390_ext.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 36 | #ifndef CONFIG_64BIT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | #define __FAIL_ADDR_MASK 0x7ffff000 |
| 38 | #define __FIXUP_MASK 0x7fffffff |
| 39 | #define __SUBCODE_MASK 0x0200 |
| 40 | #define __PF_RES_FIELD 0ULL |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 41 | #else /* CONFIG_64BIT */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | #define __FAIL_ADDR_MASK -4096L |
| 43 | #define __FIXUP_MASK ~0L |
| 44 | #define __SUBCODE_MASK 0x0600 |
| 45 | #define __PF_RES_FIELD 0x8000000000000000ULL |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 46 | #endif /* CONFIG_64BIT */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
| 48 | #ifdef CONFIG_SYSCTL |
| 49 | extern int sysctl_userprocess_debug; |
| 50 | #endif |
| 51 | |
| 52 | extern void die(const char *,struct pt_regs *,long); |
| 53 | |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 54 | #ifdef CONFIG_KPROBES |
Heiko Carstens | 2b67fc4 | 2007-02-05 21:16:47 +0100 | [diff] [blame] | 55 | static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 56 | int register_page_fault_notifier(struct notifier_block *nb) |
| 57 | { |
| 58 | return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); |
| 59 | } |
| 60 | |
| 61 | int unregister_page_fault_notifier(struct notifier_block *nb) |
| 62 | { |
| 63 | return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); |
| 64 | } |
| 65 | |
| 66 | static inline int notify_page_fault(enum die_val val, const char *str, |
| 67 | struct pt_regs *regs, long err, int trap, int sig) |
| 68 | { |
| 69 | struct die_args args = { |
| 70 | .regs = regs, |
| 71 | .str = str, |
| 72 | .err = err, |
| 73 | .trapnr = trap, |
| 74 | .signr = sig |
| 75 | }; |
| 76 | return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args); |
| 77 | } |
| 78 | #else |
| 79 | static inline int notify_page_fault(enum die_val val, const char *str, |
| 80 | struct pt_regs *regs, long err, int trap, int sig) |
| 81 | { |
| 82 | return NOTIFY_DONE; |
| 83 | } |
| 84 | #endif |
| 85 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | extern spinlock_t timerlist_lock; |
| 87 | |
| 88 | /* |
| 89 | * Unlock any spinlocks which will prevent us from getting the |
| 90 | * message out (timerlist_lock is acquired through the |
| 91 | * console unblank code) |
| 92 | */ |
| 93 | void bust_spinlocks(int yes) |
| 94 | { |
| 95 | if (yes) { |
| 96 | oops_in_progress = 1; |
| 97 | } else { |
| 98 | int loglevel_save = console_loglevel; |
| 99 | console_unblank(); |
| 100 | oops_in_progress = 0; |
| 101 | /* |
| 102 | * OK, the message is on the console. Now we call printk() |
| 103 | * without oops_in_progress set so that printk will give klogd |
| 104 | * a poke. Hold onto your hats... |
| 105 | */ |
| 106 | console_loglevel = 15; |
| 107 | printk(" "); |
| 108 | console_loglevel = loglevel_save; |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | /* |
| 113 | * Check which address space is addressed by the access |
| 114 | * register in S390_lowcore.exc_access_id. |
| 115 | * Returns 1 for user space and 0 for kernel space. |
| 116 | */ |
| 117 | static int __check_access_register(struct pt_regs *regs, int error_code) |
| 118 | { |
| 119 | int areg = S390_lowcore.exc_access_id; |
| 120 | |
| 121 | if (areg == 0) |
| 122 | /* Access via access register 0 -> kernel address */ |
| 123 | return 0; |
| 124 | save_access_regs(current->thread.acrs); |
| 125 | if (regs && areg < NUM_ACRS && current->thread.acrs[areg] <= 1) |
| 126 | /* |
| 127 | * access register contains 0 -> kernel address, |
| 128 | * access register contains 1 -> user space address |
| 129 | */ |
| 130 | return current->thread.acrs[areg]; |
| 131 | |
| 132 | /* Something unhealthy was done with the access registers... */ |
| 133 | die("page fault via unknown access register", regs, error_code); |
| 134 | do_exit(SIGKILL); |
| 135 | return 0; |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | * Check which address space the address belongs to. |
| 140 | * Returns 1 for user space and 0 for kernel space. |
| 141 | */ |
| 142 | static inline int check_user_space(struct pt_regs *regs, int error_code) |
| 143 | { |
| 144 | /* |
| 145 | * The lowest two bits of S390_lowcore.trans_exc_code indicate |
| 146 | * which paging table was used: |
| 147 | * 0: Primary Segment Table Descriptor |
| 148 | * 1: STD determined via access register |
| 149 | * 2: Secondary Segment Table Descriptor |
| 150 | * 3: Home Segment Table Descriptor |
| 151 | */ |
| 152 | int descriptor = S390_lowcore.trans_exc_code & 3; |
| 153 | if (unlikely(descriptor == 1)) |
| 154 | return __check_access_register(regs, error_code); |
| 155 | if (descriptor == 2) |
| 156 | return current->thread.mm_segment.ar4; |
| 157 | return descriptor != 0; |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * Send SIGSEGV to task. This is an external routine |
| 162 | * to keep the stack usage of do_page_fault small. |
| 163 | */ |
| 164 | static void do_sigsegv(struct pt_regs *regs, unsigned long error_code, |
| 165 | int si_code, unsigned long address) |
| 166 | { |
| 167 | struct siginfo si; |
| 168 | |
| 169 | #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG) |
| 170 | #if defined(CONFIG_SYSCTL) |
| 171 | if (sysctl_userprocess_debug) |
| 172 | #endif |
| 173 | { |
| 174 | printk("User process fault: interruption code 0x%lX\n", |
| 175 | error_code); |
| 176 | printk("failing address: %lX\n", address); |
| 177 | show_regs(regs); |
| 178 | } |
| 179 | #endif |
| 180 | si.si_signo = SIGSEGV; |
| 181 | si.si_code = si_code; |
Heiko Carstens | d2c993d | 2006-07-12 16:41:55 +0200 | [diff] [blame] | 182 | si.si_addr = (void __user *) address; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | force_sig_info(SIGSEGV, &si, current); |
| 184 | } |
| 185 | |
| 186 | /* |
| 187 | * This routine handles page faults. It determines the address, |
| 188 | * and the problem, and then passes it off to one of the appropriate |
| 189 | * routines. |
| 190 | * |
| 191 | * error_code: |
| 192 | * 04 Protection -> Write-Protection (suprression) |
| 193 | * 10 Segment translation -> Not present (nullification) |
| 194 | * 11 Page translation -> Not present (nullification) |
| 195 | * 3b Region third trans. -> Not present (nullification) |
| 196 | */ |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 197 | static inline void __kprobes |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection) |
| 199 | { |
| 200 | struct task_struct *tsk; |
| 201 | struct mm_struct *mm; |
| 202 | struct vm_area_struct * vma; |
| 203 | unsigned long address; |
| 204 | int user_address; |
| 205 | const struct exception_table_entry *fixup; |
| 206 | int si_code = SEGV_MAPERR; |
| 207 | |
| 208 | tsk = current; |
| 209 | mm = tsk->mm; |
| 210 | |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 211 | if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, |
| 212 | SIGSEGV) == NOTIFY_STOP) |
| 213 | return; |
| 214 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | /* |
| 216 | * Check for low-address protection. This needs to be treated |
| 217 | * as a special case because the translation exception code |
| 218 | * field is not guaranteed to contain valid data in this case. |
| 219 | */ |
| 220 | if (is_protection && !(S390_lowcore.trans_exc_code & 4)) { |
| 221 | |
| 222 | /* Low-address protection hit in kernel mode means |
| 223 | NULL pointer write access in kernel mode. */ |
| 224 | if (!(regs->psw.mask & PSW_MASK_PSTATE)) { |
| 225 | address = 0; |
| 226 | user_address = 0; |
| 227 | goto no_context; |
| 228 | } |
| 229 | |
| 230 | /* Low-address protection hit in user mode 'cannot happen'. */ |
| 231 | die ("Low-address protection", regs, error_code); |
| 232 | do_exit(SIGKILL); |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * get the failing address |
| 237 | * more specific the segment and page table portion of |
| 238 | * the address |
| 239 | */ |
| 240 | address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; |
| 241 | user_address = check_user_space(regs, error_code); |
| 242 | |
| 243 | /* |
| 244 | * Verify that the fault happened in user space, that |
| 245 | * we are not in an interrupt and that there is a |
| 246 | * user context. |
| 247 | */ |
Martin Schwidefsky | 595bf2a | 2005-06-04 15:43:32 -0700 | [diff] [blame] | 248 | if (user_address == 0 || in_atomic() || !mm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | goto no_context; |
| 250 | |
| 251 | /* |
| 252 | * When we get here, the fault happened in the current |
| 253 | * task's user address space, so we can switch on the |
| 254 | * interrupts again and then search the VMAs |
| 255 | */ |
| 256 | local_irq_enable(); |
| 257 | |
| 258 | down_read(&mm->mmap_sem); |
| 259 | |
| 260 | vma = find_vma(mm, address); |
| 261 | if (!vma) |
| 262 | goto bad_area; |
| 263 | if (vma->vm_start <= address) |
| 264 | goto good_area; |
| 265 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
| 266 | goto bad_area; |
| 267 | if (expand_stack(vma, address)) |
| 268 | goto bad_area; |
| 269 | /* |
| 270 | * Ok, we have a good vm_area for this memory access, so |
| 271 | * we can handle it.. |
| 272 | */ |
| 273 | good_area: |
| 274 | si_code = SEGV_ACCERR; |
| 275 | if (!is_protection) { |
| 276 | /* page not present, check vm flags */ |
| 277 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
| 278 | goto bad_area; |
| 279 | } else { |
| 280 | if (!(vma->vm_flags & VM_WRITE)) |
| 281 | goto bad_area; |
| 282 | } |
| 283 | |
| 284 | survive: |
| 285 | /* |
| 286 | * If for any reason at all we couldn't handle the fault, |
| 287 | * make sure we exit gracefully rather than endlessly redo |
| 288 | * the fault. |
| 289 | */ |
| 290 | switch (handle_mm_fault(mm, vma, address, is_protection)) { |
| 291 | case VM_FAULT_MINOR: |
| 292 | tsk->min_flt++; |
| 293 | break; |
| 294 | case VM_FAULT_MAJOR: |
| 295 | tsk->maj_flt++; |
| 296 | break; |
| 297 | case VM_FAULT_SIGBUS: |
| 298 | goto do_sigbus; |
| 299 | case VM_FAULT_OOM: |
| 300 | goto out_of_memory; |
| 301 | default: |
| 302 | BUG(); |
| 303 | } |
| 304 | |
| 305 | up_read(&mm->mmap_sem); |
| 306 | /* |
| 307 | * The instruction that caused the program check will |
| 308 | * be repeated. Don't signal single step via SIGTRAP. |
| 309 | */ |
| 310 | clear_tsk_thread_flag(current, TIF_SINGLE_STEP); |
| 311 | return; |
| 312 | |
| 313 | /* |
| 314 | * Something tried to access memory that isn't in our memory map.. |
| 315 | * Fix it, but check if it's kernel or user first.. |
| 316 | */ |
| 317 | bad_area: |
| 318 | up_read(&mm->mmap_sem); |
| 319 | |
| 320 | /* User mode accesses just cause a SIGSEGV */ |
| 321 | if (regs->psw.mask & PSW_MASK_PSTATE) { |
| 322 | tsk->thread.prot_addr = address; |
| 323 | tsk->thread.trap_no = error_code; |
| 324 | do_sigsegv(regs, error_code, si_code, address); |
| 325 | return; |
| 326 | } |
| 327 | |
| 328 | no_context: |
| 329 | /* Are we prepared to handle this kernel fault? */ |
| 330 | fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK); |
| 331 | if (fixup) { |
| 332 | regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; |
| 333 | return; |
| 334 | } |
| 335 | |
| 336 | /* |
| 337 | * Oops. The kernel tried to access some bad page. We'll have to |
| 338 | * terminate things with extreme prejudice. |
| 339 | */ |
| 340 | if (user_address == 0) |
| 341 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" |
| 342 | " at virtual kernel address %p\n", (void *)address); |
| 343 | else |
| 344 | printk(KERN_ALERT "Unable to handle kernel paging request" |
| 345 | " at virtual user address %p\n", (void *)address); |
| 346 | |
| 347 | die("Oops", regs, error_code); |
| 348 | do_exit(SIGKILL); |
| 349 | |
| 350 | |
| 351 | /* |
| 352 | * We ran out of memory, or some other thing happened to us that made |
| 353 | * us unable to handle the page fault gracefully. |
| 354 | */ |
| 355 | out_of_memory: |
| 356 | up_read(&mm->mmap_sem); |
Sukadev Bhattiprolu | f400e19 | 2006-09-29 02:00:07 -0700 | [diff] [blame] | 357 | if (is_init(tsk)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | yield(); |
Akinobu Mita | bac9c66 | 2006-09-28 16:55:18 +0200 | [diff] [blame] | 359 | down_read(&mm->mmap_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | goto survive; |
| 361 | } |
| 362 | printk("VM: killing process %s\n", tsk->comm); |
| 363 | if (regs->psw.mask & PSW_MASK_PSTATE) |
| 364 | do_exit(SIGKILL); |
| 365 | goto no_context; |
| 366 | |
| 367 | do_sigbus: |
| 368 | up_read(&mm->mmap_sem); |
| 369 | |
| 370 | /* |
| 371 | * Send a sigbus, regardless of whether we were in kernel |
| 372 | * or user mode. |
| 373 | */ |
| 374 | tsk->thread.prot_addr = address; |
| 375 | tsk->thread.trap_no = error_code; |
| 376 | force_sig(SIGBUS, tsk); |
| 377 | |
| 378 | /* Kernel mode? Handle exceptions or die */ |
| 379 | if (!(regs->psw.mask & PSW_MASK_PSTATE)) |
| 380 | goto no_context; |
| 381 | } |
| 382 | |
| 383 | void do_protection_exception(struct pt_regs *regs, unsigned long error_code) |
| 384 | { |
| 385 | regs->psw.addr -= (error_code >> 16); |
| 386 | do_exception(regs, 4, 1); |
| 387 | } |
| 388 | |
| 389 | void do_dat_exception(struct pt_regs *regs, unsigned long error_code) |
| 390 | { |
| 391 | do_exception(regs, error_code & 0xff, 0); |
| 392 | } |
| 393 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | #ifdef CONFIG_PFAULT |
| 395 | /* |
| 396 | * 'pfault' pseudo page faults routines. |
| 397 | */ |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 398 | static ext_int_info_t ext_int_pfault; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | static int pfault_disable = 0; |
| 400 | |
| 401 | static int __init nopfault(char *str) |
| 402 | { |
| 403 | pfault_disable = 1; |
| 404 | return 1; |
| 405 | } |
| 406 | |
| 407 | __setup("nopfault", nopfault); |
| 408 | |
| 409 | typedef struct { |
| 410 | __u16 refdiagc; |
| 411 | __u16 reffcode; |
| 412 | __u16 refdwlen; |
| 413 | __u16 refversn; |
| 414 | __u64 refgaddr; |
| 415 | __u64 refselmk; |
| 416 | __u64 refcmpmk; |
| 417 | __u64 reserved; |
| 418 | } __attribute__ ((packed)) pfault_refbk_t; |
| 419 | |
| 420 | int pfault_init(void) |
| 421 | { |
| 422 | pfault_refbk_t refbk = |
| 423 | { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, |
| 424 | __PF_RES_FIELD }; |
| 425 | int rc; |
| 426 | |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 427 | if (!MACHINE_IS_VM || pfault_disable) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | return -1; |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 429 | asm volatile( |
| 430 | " diag %1,%0,0x258\n" |
| 431 | "0: j 2f\n" |
| 432 | "1: la %0,8\n" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | "2:\n" |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 434 | EX_TABLE(0b,1b) |
| 435 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | __ctl_set_bit(0, 9); |
| 437 | return rc; |
| 438 | } |
| 439 | |
| 440 | void pfault_fini(void) |
| 441 | { |
| 442 | pfault_refbk_t refbk = |
| 443 | { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; |
| 444 | |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 445 | if (!MACHINE_IS_VM || pfault_disable) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | return; |
| 447 | __ctl_clear_bit(0,9); |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 448 | asm volatile( |
| 449 | " diag %0,0,0x258\n" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | "0:\n" |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 451 | EX_TABLE(0b,0b) |
| 452 | : : "a" (&refbk), "m" (refbk) : "cc"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | } |
| 454 | |
Heiko Carstens | 2b67fc4 | 2007-02-05 21:16:47 +0100 | [diff] [blame] | 455 | static void pfault_interrupt(__u16 error_code) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | { |
| 457 | struct task_struct *tsk; |
| 458 | __u16 subcode; |
| 459 | |
| 460 | /* |
| 461 | * Get the external interruption subcode & pfault |
| 462 | * initial/completion signal bit. VM stores this |
| 463 | * in the 'cpu address' field associated with the |
| 464 | * external interrupt. |
| 465 | */ |
| 466 | subcode = S390_lowcore.cpu_addr; |
| 467 | if ((subcode & 0xff00) != __SUBCODE_MASK) |
| 468 | return; |
| 469 | |
| 470 | /* |
| 471 | * Get the token (= address of the task structure of the affected task). |
| 472 | */ |
| 473 | tsk = *(struct task_struct **) __LC_PFAULT_INTPARM; |
| 474 | |
| 475 | if (subcode & 0x0080) { |
| 476 | /* signal bit is set -> a page has been swapped in by VM */ |
| 477 | if (xchg(&tsk->thread.pfault_wait, -1) != 0) { |
| 478 | /* Initial interrupt was faster than the completion |
| 479 | * interrupt. pfault_wait is valid. Set pfault_wait |
| 480 | * back to zero and wake up the process. This can |
| 481 | * safely be done because the task is still sleeping |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 482 | * and can't produce new pfaults. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 483 | tsk->thread.pfault_wait = 0; |
| 484 | wake_up_process(tsk); |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 485 | put_task_struct(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | } |
| 487 | } else { |
| 488 | /* signal bit not set -> a real page is missing. */ |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 489 | get_task_struct(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
| 491 | if (xchg(&tsk->thread.pfault_wait, 1) != 0) { |
| 492 | /* Completion interrupt was faster than the initial |
| 493 | * interrupt (swapped in a -1 for pfault_wait). Set |
| 494 | * pfault_wait back to zero and exit. This can be |
| 495 | * done safely because tsk is running in kernel |
| 496 | * mode and can't produce new pfaults. */ |
| 497 | tsk->thread.pfault_wait = 0; |
| 498 | set_task_state(tsk, TASK_RUNNING); |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 499 | put_task_struct(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | } else |
| 501 | set_tsk_need_resched(tsk); |
| 502 | } |
| 503 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 505 | void __init pfault_irq_init(void) |
| 506 | { |
| 507 | if (!MACHINE_IS_VM) |
| 508 | return; |
| 509 | |
| 510 | /* |
| 511 | * Try to get pfault pseudo page faults going. |
| 512 | */ |
| 513 | if (register_early_external_interrupt(0x2603, pfault_interrupt, |
| 514 | &ext_int_pfault) != 0) |
| 515 | panic("Couldn't request external interrupt 0x2603"); |
| 516 | |
| 517 | if (pfault_init() == 0) |
| 518 | return; |
| 519 | |
| 520 | /* Tough luck, no pfault. */ |
| 521 | pfault_disable = 1; |
| 522 | unregister_early_external_interrupt(0x2603, pfault_interrupt, |
| 523 | &ext_int_pfault); |
| 524 | } |
| 525 | #endif |