Commit | Line | Data |
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1da177e4 LT |
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 | ||
1da177e4 LT |
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> | |
1eeb66a1 | 23 | #include <linux/kdebug.h> |
1da177e4 LT |
24 | #include <linux/smp_lock.h> |
25 | #include <linux/init.h> | |
26 | #include <linux/console.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/hardirq.h> | |
4ba069b8 | 29 | #include <linux/kprobes.h> |
be5ec363 | 30 | #include <linux/uaccess.h> |
53492b1d | 31 | #include <linux/hugetlb.h> |
1da177e4 | 32 | #include <asm/system.h> |
1da177e4 | 33 | #include <asm/pgtable.h> |
29b08d2b | 34 | #include <asm/s390_ext.h> |
6252d702 | 35 | #include <asm/mmu_context.h> |
a806170e | 36 | #include "../kernel/entry.h" |
1da177e4 | 37 | |
347a8dc3 | 38 | #ifndef CONFIG_64BIT |
1da177e4 LT |
39 | #define __FAIL_ADDR_MASK 0x7ffff000 |
40 | #define __FIXUP_MASK 0x7fffffff | |
41 | #define __SUBCODE_MASK 0x0200 | |
42 | #define __PF_RES_FIELD 0ULL | |
347a8dc3 | 43 | #else /* CONFIG_64BIT */ |
1da177e4 LT |
44 | #define __FAIL_ADDR_MASK -4096L |
45 | #define __FIXUP_MASK ~0L | |
46 | #define __SUBCODE_MASK 0x0600 | |
47 | #define __PF_RES_FIELD 0x8000000000000000ULL | |
347a8dc3 | 48 | #endif /* CONFIG_64BIT */ |
1da177e4 LT |
49 | |
50 | #ifdef CONFIG_SYSCTL | |
51 | extern int sysctl_userprocess_debug; | |
52 | #endif | |
53 | ||
4ba069b8 | 54 | #ifdef CONFIG_KPROBES |
10c1031f MS |
55 | static inline int notify_page_fault(struct pt_regs *regs, long err) |
56 | { | |
33464e3b CH |
57 | int ret = 0; |
58 | ||
59 | /* kprobe_running() needs smp_processor_id() */ | |
60 | if (!user_mode(regs)) { | |
61 | preempt_disable(); | |
62 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
63 | ret = 1; | |
64 | preempt_enable(); | |
65 | } | |
66 | ||
67 | return ret; | |
4ba069b8 MG |
68 | } |
69 | #else | |
10c1031f | 70 | static inline int notify_page_fault(struct pt_regs *regs, long err) |
4ba069b8 | 71 | { |
33464e3b | 72 | return 0; |
4ba069b8 MG |
73 | } |
74 | #endif | |
75 | ||
1da177e4 LT |
76 | |
77 | /* | |
78 | * Unlock any spinlocks which will prevent us from getting the | |
cefc8be8 | 79 | * message out. |
1da177e4 LT |
80 | */ |
81 | void bust_spinlocks(int yes) | |
82 | { | |
83 | if (yes) { | |
84 | oops_in_progress = 1; | |
85 | } else { | |
86 | int loglevel_save = console_loglevel; | |
87 | console_unblank(); | |
88 | oops_in_progress = 0; | |
89 | /* | |
90 | * OK, the message is on the console. Now we call printk() | |
91 | * without oops_in_progress set so that printk will give klogd | |
92 | * a poke. Hold onto your hats... | |
93 | */ | |
94 | console_loglevel = 15; | |
95 | printk(" "); | |
96 | console_loglevel = loglevel_save; | |
97 | } | |
98 | } | |
99 | ||
100 | /* | |
482b05dd GS |
101 | * Returns the address space associated with the fault. |
102 | * Returns 0 for kernel space, 1 for user space and | |
103 | * 2 for code execution in user space with noexec=on. | |
1da177e4 | 104 | */ |
482b05dd | 105 | static inline int check_space(struct task_struct *tsk) |
1da177e4 LT |
106 | { |
107 | /* | |
482b05dd GS |
108 | * The lowest two bits of S390_lowcore.trans_exc_code |
109 | * indicate which paging table was used. | |
1da177e4 | 110 | */ |
482b05dd GS |
111 | int desc = S390_lowcore.trans_exc_code & 3; |
112 | ||
113 | if (desc == 3) /* Home Segment Table Descriptor */ | |
114 | return switch_amode == 0; | |
115 | if (desc == 2) /* Secondary Segment Table Descriptor */ | |
116 | return tsk->thread.mm_segment.ar4; | |
117 | #ifdef CONFIG_S390_SWITCH_AMODE | |
118 | if (unlikely(desc == 1)) { /* STD determined via access register */ | |
119 | /* %a0 always indicates primary space. */ | |
120 | if (S390_lowcore.exc_access_id != 0) { | |
121 | save_access_regs(tsk->thread.acrs); | |
122 | /* | |
123 | * An alet of 0 indicates primary space. | |
124 | * An alet of 1 indicates secondary space. | |
125 | * Any other alet values generate an | |
126 | * alen-translation exception. | |
127 | */ | |
128 | if (tsk->thread.acrs[S390_lowcore.exc_access_id]) | |
129 | return tsk->thread.mm_segment.ar4; | |
130 | } | |
131 | } | |
132 | #endif | |
133 | /* Primary Segment Table Descriptor */ | |
134 | return switch_amode << s390_noexec; | |
1da177e4 LT |
135 | } |
136 | ||
137 | /* | |
138 | * Send SIGSEGV to task. This is an external routine | |
139 | * to keep the stack usage of do_page_fault small. | |
140 | */ | |
141 | static void do_sigsegv(struct pt_regs *regs, unsigned long error_code, | |
142 | int si_code, unsigned long address) | |
143 | { | |
144 | struct siginfo si; | |
145 | ||
146 | #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG) | |
147 | #if defined(CONFIG_SYSCTL) | |
148 | if (sysctl_userprocess_debug) | |
149 | #endif | |
150 | { | |
151 | printk("User process fault: interruption code 0x%lX\n", | |
152 | error_code); | |
153 | printk("failing address: %lX\n", address); | |
154 | show_regs(regs); | |
155 | } | |
156 | #endif | |
157 | si.si_signo = SIGSEGV; | |
158 | si.si_code = si_code; | |
d2c993d8 | 159 | si.si_addr = (void __user *) address; |
1da177e4 LT |
160 | force_sig_info(SIGSEGV, &si, current); |
161 | } | |
162 | ||
10c1031f MS |
163 | static void do_no_context(struct pt_regs *regs, unsigned long error_code, |
164 | unsigned long address) | |
165 | { | |
166 | const struct exception_table_entry *fixup; | |
167 | ||
168 | /* Are we prepared to handle this kernel fault? */ | |
169 | fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK); | |
170 | if (fixup) { | |
171 | regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; | |
172 | return; | |
173 | } | |
174 | ||
175 | /* | |
176 | * Oops. The kernel tried to access some bad page. We'll have to | |
177 | * terminate things with extreme prejudice. | |
178 | */ | |
179 | if (check_space(current) == 0) | |
180 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" | |
181 | " at virtual kernel address %p\n", (void *)address); | |
182 | else | |
183 | printk(KERN_ALERT "Unable to handle kernel paging request" | |
184 | " at virtual user address %p\n", (void *)address); | |
185 | ||
186 | die("Oops", regs, error_code); | |
187 | do_exit(SIGKILL); | |
188 | } | |
189 | ||
190 | static void do_low_address(struct pt_regs *regs, unsigned long error_code) | |
191 | { | |
192 | /* Low-address protection hit in kernel mode means | |
193 | NULL pointer write access in kernel mode. */ | |
194 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
195 | /* Low-address protection hit in user mode 'cannot happen'. */ | |
196 | die ("Low-address protection", regs, error_code); | |
197 | do_exit(SIGKILL); | |
198 | } | |
199 | ||
200 | do_no_context(regs, error_code, 0); | |
201 | } | |
202 | ||
10c1031f MS |
203 | static void do_sigbus(struct pt_regs *regs, unsigned long error_code, |
204 | unsigned long address) | |
205 | { | |
206 | struct task_struct *tsk = current; | |
207 | struct mm_struct *mm = tsk->mm; | |
208 | ||
209 | up_read(&mm->mmap_sem); | |
210 | /* | |
211 | * Send a sigbus, regardless of whether we were in kernel | |
212 | * or user mode. | |
213 | */ | |
214 | tsk->thread.prot_addr = address; | |
215 | tsk->thread.trap_no = error_code; | |
216 | force_sig(SIGBUS, tsk); | |
217 | ||
218 | /* Kernel mode? Handle exceptions or die */ | |
219 | if (!(regs->psw.mask & PSW_MASK_PSTATE)) | |
220 | do_no_context(regs, error_code, address); | |
221 | } | |
222 | ||
c1821c2e | 223 | #ifdef CONFIG_S390_EXEC_PROTECT |
be5ec363 MS |
224 | static int signal_return(struct mm_struct *mm, struct pt_regs *regs, |
225 | unsigned long address, unsigned long error_code) | |
c1821c2e | 226 | { |
be5ec363 | 227 | u16 instruction; |
490f03d6 HC |
228 | int rc; |
229 | #ifdef CONFIG_COMPAT | |
230 | int compat; | |
231 | #endif | |
be5ec363 MS |
232 | |
233 | pagefault_disable(); | |
234 | rc = __get_user(instruction, (u16 __user *) regs->psw.addr); | |
235 | pagefault_enable(); | |
236 | if (rc) | |
237 | return -EFAULT; | |
238 | ||
c1821c2e GS |
239 | up_read(&mm->mmap_sem); |
240 | clear_tsk_thread_flag(current, TIF_SINGLE_STEP); | |
241 | #ifdef CONFIG_COMPAT | |
be5ec363 MS |
242 | compat = test_tsk_thread_flag(current, TIF_31BIT); |
243 | if (compat && instruction == 0x0a77) | |
c2e8b853 | 244 | sys32_sigreturn(); |
be5ec363 | 245 | else if (compat && instruction == 0x0aad) |
c2e8b853 | 246 | sys32_rt_sigreturn(); |
c1821c2e | 247 | else |
be5ec363 MS |
248 | #endif |
249 | if (instruction == 0x0a77) | |
c2e8b853 | 250 | sys_sigreturn(); |
be5ec363 | 251 | else if (instruction == 0x0aad) |
c2e8b853 | 252 | sys_rt_sigreturn(); |
c1821c2e | 253 | else { |
c1821c2e GS |
254 | current->thread.prot_addr = address; |
255 | current->thread.trap_no = error_code; | |
256 | do_sigsegv(regs, error_code, SEGV_MAPERR, address); | |
257 | } | |
258 | return 0; | |
c1821c2e GS |
259 | } |
260 | #endif /* CONFIG_S390_EXEC_PROTECT */ | |
261 | ||
1da177e4 LT |
262 | /* |
263 | * This routine handles page faults. It determines the address, | |
264 | * and the problem, and then passes it off to one of the appropriate | |
265 | * routines. | |
266 | * | |
267 | * error_code: | |
268 | * 04 Protection -> Write-Protection (suprression) | |
269 | * 10 Segment translation -> Not present (nullification) | |
270 | * 11 Page translation -> Not present (nullification) | |
271 | * 3b Region third trans. -> Not present (nullification) | |
272 | */ | |
482b05dd | 273 | static inline void |
10c1031f | 274 | do_exception(struct pt_regs *regs, unsigned long error_code, int write) |
1da177e4 | 275 | { |
10c1031f MS |
276 | struct task_struct *tsk; |
277 | struct mm_struct *mm; | |
278 | struct vm_area_struct *vma; | |
279 | unsigned long address; | |
482b05dd | 280 | int space; |
10c1031f | 281 | int si_code; |
83c54070 | 282 | int fault; |
1da177e4 | 283 | |
33464e3b | 284 | if (notify_page_fault(regs, error_code)) |
4ba069b8 MG |
285 | return; |
286 | ||
10c1031f MS |
287 | tsk = current; |
288 | mm = tsk->mm; | |
1da177e4 | 289 | |
10c1031f MS |
290 | /* get the failing address and the affected space */ |
291 | address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; | |
482b05dd | 292 | space = check_space(tsk); |
1da177e4 LT |
293 | |
294 | /* | |
295 | * Verify that the fault happened in user space, that | |
296 | * we are not in an interrupt and that there is a | |
297 | * user context. | |
298 | */ | |
482b05dd GS |
299 | if (unlikely(space == 0 || in_atomic() || !mm)) |
300 | goto no_context; | |
1da177e4 LT |
301 | |
302 | /* | |
303 | * When we get here, the fault happened in the current | |
304 | * task's user address space, so we can switch on the | |
305 | * interrupts again and then search the VMAs | |
306 | */ | |
307 | local_irq_enable(); | |
308 | ||
10c1031f | 309 | down_read(&mm->mmap_sem); |
1da177e4 | 310 | |
482b05dd GS |
311 | si_code = SEGV_MAPERR; |
312 | vma = find_vma(mm, address); | |
313 | if (!vma) | |
314 | goto bad_area; | |
c1821c2e GS |
315 | |
316 | #ifdef CONFIG_S390_EXEC_PROTECT | |
482b05dd | 317 | if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC))) |
c1821c2e GS |
318 | if (!signal_return(mm, regs, address, error_code)) |
319 | /* | |
320 | * signal_return() has done an up_read(&mm->mmap_sem) | |
321 | * if it returns 0. | |
322 | */ | |
323 | return; | |
324 | #endif | |
325 | ||
10c1031f MS |
326 | if (vma->vm_start <= address) |
327 | goto good_area; | |
328 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
329 | goto bad_area; | |
330 | if (expand_stack(vma, address)) | |
331 | goto bad_area; | |
1da177e4 LT |
332 | /* |
333 | * Ok, we have a good vm_area for this memory access, so | |
334 | * we can handle it.. | |
335 | */ | |
336 | good_area: | |
337 | si_code = SEGV_ACCERR; | |
10c1031f | 338 | if (!write) { |
1da177e4 LT |
339 | /* page not present, check vm flags */ |
340 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) | |
341 | goto bad_area; | |
342 | } else { | |
343 | if (!(vma->vm_flags & VM_WRITE)) | |
344 | goto bad_area; | |
345 | } | |
346 | ||
53492b1d GS |
347 | if (is_vm_hugetlb_page(vma)) |
348 | address &= HPAGE_MASK; | |
1da177e4 LT |
349 | /* |
350 | * If for any reason at all we couldn't handle the fault, | |
351 | * make sure we exit gracefully rather than endlessly redo | |
352 | * the fault. | |
353 | */ | |
83c54070 NP |
354 | fault = handle_mm_fault(mm, vma, address, write); |
355 | if (unlikely(fault & VM_FAULT_ERROR)) { | |
356 | if (fault & VM_FAULT_OOM) { | |
59fa4392 HC |
357 | up_read(&mm->mmap_sem); |
358 | pagefault_out_of_memory(); | |
83c54070 NP |
359 | return; |
360 | } else if (fault & VM_FAULT_SIGBUS) { | |
361 | do_sigbus(regs, error_code, address); | |
362 | return; | |
363 | } | |
1da177e4 LT |
364 | BUG(); |
365 | } | |
83c54070 NP |
366 | if (fault & VM_FAULT_MAJOR) |
367 | tsk->maj_flt++; | |
368 | else | |
369 | tsk->min_flt++; | |
1da177e4 LT |
370 | |
371 | up_read(&mm->mmap_sem); | |
372 | /* | |
373 | * The instruction that caused the program check will | |
374 | * be repeated. Don't signal single step via SIGTRAP. | |
375 | */ | |
482b05dd | 376 | clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP); |
1da177e4 LT |
377 | return; |
378 | ||
379 | /* | |
380 | * Something tried to access memory that isn't in our memory map.. | |
381 | * Fix it, but check if it's kernel or user first.. | |
382 | */ | |
383 | bad_area: | |
10c1031f | 384 | up_read(&mm->mmap_sem); |
1da177e4 | 385 | |
10c1031f MS |
386 | /* User mode accesses just cause a SIGSEGV */ |
387 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
388 | tsk->thread.prot_addr = address; | |
389 | tsk->thread.trap_no = error_code; | |
1da177e4 | 390 | do_sigsegv(regs, error_code, si_code, address); |
10c1031f | 391 | return; |
1da177e4 LT |
392 | } |
393 | ||
394 | no_context: | |
10c1031f | 395 | do_no_context(regs, error_code, address); |
1da177e4 LT |
396 | } |
397 | ||
482b05dd | 398 | void __kprobes do_protection_exception(struct pt_regs *regs, |
a806170e | 399 | long error_code) |
1da177e4 | 400 | { |
10c1031f | 401 | /* Protection exception is supressing, decrement psw address. */ |
1da177e4 | 402 | regs->psw.addr -= (error_code >> 16); |
10c1031f MS |
403 | /* |
404 | * Check for low-address protection. This needs to be treated | |
405 | * as a special case because the translation exception code | |
406 | * field is not guaranteed to contain valid data in this case. | |
407 | */ | |
408 | if (unlikely(!(S390_lowcore.trans_exc_code & 4))) { | |
409 | do_low_address(regs, error_code); | |
410 | return; | |
411 | } | |
1da177e4 LT |
412 | do_exception(regs, 4, 1); |
413 | } | |
414 | ||
a806170e | 415 | void __kprobes do_dat_exception(struct pt_regs *regs, long error_code) |
1da177e4 LT |
416 | { |
417 | do_exception(regs, error_code & 0xff, 0); | |
418 | } | |
419 | ||
6252d702 MS |
420 | #ifdef CONFIG_64BIT |
421 | void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code) | |
422 | { | |
423 | struct mm_struct *mm; | |
424 | struct vm_area_struct *vma; | |
425 | unsigned long address; | |
426 | int space; | |
427 | ||
428 | mm = current->mm; | |
429 | address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; | |
430 | space = check_space(current); | |
431 | ||
432 | if (unlikely(space == 0 || in_atomic() || !mm)) | |
433 | goto no_context; | |
434 | ||
435 | local_irq_enable(); | |
436 | ||
437 | down_read(&mm->mmap_sem); | |
438 | vma = find_vma(mm, address); | |
439 | up_read(&mm->mmap_sem); | |
440 | ||
441 | if (vma) { | |
442 | update_mm(mm, current); | |
443 | return; | |
444 | } | |
445 | ||
446 | /* User mode accesses just cause a SIGSEGV */ | |
447 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
448 | current->thread.prot_addr = address; | |
449 | current->thread.trap_no = error_code; | |
450 | do_sigsegv(regs, error_code, SEGV_MAPERR, address); | |
451 | return; | |
452 | } | |
453 | ||
454 | no_context: | |
455 | do_no_context(regs, error_code, address); | |
456 | } | |
457 | #endif | |
458 | ||
1da177e4 LT |
459 | #ifdef CONFIG_PFAULT |
460 | /* | |
461 | * 'pfault' pseudo page faults routines. | |
462 | */ | |
29b08d2b | 463 | static ext_int_info_t ext_int_pfault; |
1da177e4 LT |
464 | static int pfault_disable = 0; |
465 | ||
466 | static int __init nopfault(char *str) | |
467 | { | |
468 | pfault_disable = 1; | |
469 | return 1; | |
470 | } | |
471 | ||
472 | __setup("nopfault", nopfault); | |
473 | ||
474 | typedef struct { | |
475 | __u16 refdiagc; | |
476 | __u16 reffcode; | |
477 | __u16 refdwlen; | |
478 | __u16 refversn; | |
479 | __u64 refgaddr; | |
480 | __u64 refselmk; | |
481 | __u64 refcmpmk; | |
482 | __u64 reserved; | |
c41fbc69 | 483 | } __attribute__ ((packed, aligned(8))) pfault_refbk_t; |
1da177e4 LT |
484 | |
485 | int pfault_init(void) | |
486 | { | |
487 | pfault_refbk_t refbk = | |
488 | { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, | |
489 | __PF_RES_FIELD }; | |
490 | int rc; | |
491 | ||
29b08d2b | 492 | if (!MACHINE_IS_VM || pfault_disable) |
1da177e4 | 493 | return -1; |
94c12cc7 MS |
494 | asm volatile( |
495 | " diag %1,%0,0x258\n" | |
496 | "0: j 2f\n" | |
497 | "1: la %0,8\n" | |
1da177e4 | 498 | "2:\n" |
94c12cc7 MS |
499 | EX_TABLE(0b,1b) |
500 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
501 | __ctl_set_bit(0, 9); |
502 | return rc; | |
503 | } | |
504 | ||
505 | void pfault_fini(void) | |
506 | { | |
507 | pfault_refbk_t refbk = | |
508 | { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; | |
509 | ||
29b08d2b | 510 | if (!MACHINE_IS_VM || pfault_disable) |
1da177e4 LT |
511 | return; |
512 | __ctl_clear_bit(0,9); | |
94c12cc7 MS |
513 | asm volatile( |
514 | " diag %0,0,0x258\n" | |
1da177e4 | 515 | "0:\n" |
94c12cc7 MS |
516 | EX_TABLE(0b,0b) |
517 | : : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
518 | } |
519 | ||
2b67fc46 | 520 | static void pfault_interrupt(__u16 error_code) |
1da177e4 LT |
521 | { |
522 | struct task_struct *tsk; | |
523 | __u16 subcode; | |
524 | ||
525 | /* | |
526 | * Get the external interruption subcode & pfault | |
527 | * initial/completion signal bit. VM stores this | |
528 | * in the 'cpu address' field associated with the | |
529 | * external interrupt. | |
530 | */ | |
531 | subcode = S390_lowcore.cpu_addr; | |
532 | if ((subcode & 0xff00) != __SUBCODE_MASK) | |
533 | return; | |
534 | ||
535 | /* | |
536 | * Get the token (= address of the task structure of the affected task). | |
537 | */ | |
538 | tsk = *(struct task_struct **) __LC_PFAULT_INTPARM; | |
539 | ||
540 | if (subcode & 0x0080) { | |
541 | /* signal bit is set -> a page has been swapped in by VM */ | |
542 | if (xchg(&tsk->thread.pfault_wait, -1) != 0) { | |
543 | /* Initial interrupt was faster than the completion | |
544 | * interrupt. pfault_wait is valid. Set pfault_wait | |
545 | * back to zero and wake up the process. This can | |
546 | * safely be done because the task is still sleeping | |
b6d09449 | 547 | * and can't produce new pfaults. */ |
1da177e4 LT |
548 | tsk->thread.pfault_wait = 0; |
549 | wake_up_process(tsk); | |
b6d09449 | 550 | put_task_struct(tsk); |
1da177e4 LT |
551 | } |
552 | } else { | |
553 | /* signal bit not set -> a real page is missing. */ | |
b6d09449 | 554 | get_task_struct(tsk); |
1da177e4 LT |
555 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
556 | if (xchg(&tsk->thread.pfault_wait, 1) != 0) { | |
557 | /* Completion interrupt was faster than the initial | |
558 | * interrupt (swapped in a -1 for pfault_wait). Set | |
559 | * pfault_wait back to zero and exit. This can be | |
560 | * done safely because tsk is running in kernel | |
561 | * mode and can't produce new pfaults. */ | |
562 | tsk->thread.pfault_wait = 0; | |
563 | set_task_state(tsk, TASK_RUNNING); | |
b6d09449 | 564 | put_task_struct(tsk); |
1da177e4 LT |
565 | } else |
566 | set_tsk_need_resched(tsk); | |
567 | } | |
568 | } | |
1da177e4 | 569 | |
29b08d2b HC |
570 | void __init pfault_irq_init(void) |
571 | { | |
572 | if (!MACHINE_IS_VM) | |
573 | return; | |
574 | ||
575 | /* | |
576 | * Try to get pfault pseudo page faults going. | |
577 | */ | |
578 | if (register_early_external_interrupt(0x2603, pfault_interrupt, | |
579 | &ext_int_pfault) != 0) | |
580 | panic("Couldn't request external interrupt 0x2603"); | |
581 | ||
582 | if (pfault_init() == 0) | |
583 | return; | |
584 | ||
585 | /* Tough luck, no pfault. */ | |
586 | pfault_disable = 1; | |
587 | unregister_early_external_interrupt(0x2603, pfault_interrupt, | |
588 | &ext_int_pfault); | |
589 | } | |
590 | #endif |