Commit | Line | Data |
---|---|---|
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 | ||
cdd6c482 | 13 | #include <linux/perf_event.h> |
1da177e4 LT |
14 | #include <linux/signal.h> |
15 | #include <linux/sched.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/errno.h> | |
18 | #include <linux/string.h> | |
19 | #include <linux/types.h> | |
20 | #include <linux/ptrace.h> | |
21 | #include <linux/mman.h> | |
22 | #include <linux/mm.h> | |
7757591a | 23 | #include <linux/compat.h> |
1da177e4 | 24 | #include <linux/smp.h> |
1eeb66a1 | 25 | #include <linux/kdebug.h> |
1da177e4 LT |
26 | #include <linux/init.h> |
27 | #include <linux/console.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/hardirq.h> | |
4ba069b8 | 30 | #include <linux/kprobes.h> |
be5ec363 | 31 | #include <linux/uaccess.h> |
53492b1d | 32 | #include <linux/hugetlb.h> |
1da177e4 | 33 | #include <asm/system.h> |
1da177e4 | 34 | #include <asm/pgtable.h> |
29b08d2b | 35 | #include <asm/s390_ext.h> |
6252d702 | 36 | #include <asm/mmu_context.h> |
a806170e | 37 | #include "../kernel/entry.h" |
1da177e4 | 38 | |
347a8dc3 | 39 | #ifndef CONFIG_64BIT |
1da177e4 LT |
40 | #define __FAIL_ADDR_MASK 0x7ffff000 |
41 | #define __FIXUP_MASK 0x7fffffff | |
42 | #define __SUBCODE_MASK 0x0200 | |
43 | #define __PF_RES_FIELD 0ULL | |
347a8dc3 | 44 | #else /* CONFIG_64BIT */ |
1da177e4 LT |
45 | #define __FAIL_ADDR_MASK -4096L |
46 | #define __FIXUP_MASK ~0L | |
47 | #define __SUBCODE_MASK 0x0600 | |
48 | #define __PF_RES_FIELD 0x8000000000000000ULL | |
347a8dc3 | 49 | #endif /* CONFIG_64BIT */ |
1da177e4 LT |
50 | |
51 | #ifdef CONFIG_SYSCTL | |
52 | extern int sysctl_userprocess_debug; | |
53 | #endif | |
54 | ||
4ba069b8 | 55 | #ifdef CONFIG_KPROBES |
10c1031f MS |
56 | static inline int notify_page_fault(struct pt_regs *regs, long err) |
57 | { | |
33464e3b CH |
58 | int ret = 0; |
59 | ||
60 | /* kprobe_running() needs smp_processor_id() */ | |
61 | if (!user_mode(regs)) { | |
62 | preempt_disable(); | |
63 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
64 | ret = 1; | |
65 | preempt_enable(); | |
66 | } | |
67 | ||
68 | return ret; | |
4ba069b8 MG |
69 | } |
70 | #else | |
10c1031f | 71 | static inline int notify_page_fault(struct pt_regs *regs, long err) |
4ba069b8 | 72 | { |
33464e3b | 73 | return 0; |
4ba069b8 MG |
74 | } |
75 | #endif | |
76 | ||
1da177e4 LT |
77 | |
78 | /* | |
79 | * Unlock any spinlocks which will prevent us from getting the | |
cefc8be8 | 80 | * message out. |
1da177e4 LT |
81 | */ |
82 | void bust_spinlocks(int yes) | |
83 | { | |
84 | if (yes) { | |
85 | oops_in_progress = 1; | |
86 | } else { | |
87 | int loglevel_save = console_loglevel; | |
88 | console_unblank(); | |
89 | oops_in_progress = 0; | |
90 | /* | |
91 | * OK, the message is on the console. Now we call printk() | |
92 | * without oops_in_progress set so that printk will give klogd | |
93 | * a poke. Hold onto your hats... | |
94 | */ | |
95 | console_loglevel = 15; | |
96 | printk(" "); | |
97 | console_loglevel = loglevel_save; | |
98 | } | |
99 | } | |
100 | ||
101 | /* | |
482b05dd GS |
102 | * Returns the address space associated with the fault. |
103 | * Returns 0 for kernel space, 1 for user space and | |
104 | * 2 for code execution in user space with noexec=on. | |
1da177e4 | 105 | */ |
482b05dd | 106 | static inline int check_space(struct task_struct *tsk) |
1da177e4 LT |
107 | { |
108 | /* | |
482b05dd GS |
109 | * The lowest two bits of S390_lowcore.trans_exc_code |
110 | * indicate which paging table was used. | |
1da177e4 | 111 | */ |
482b05dd GS |
112 | int desc = S390_lowcore.trans_exc_code & 3; |
113 | ||
114 | if (desc == 3) /* Home Segment Table Descriptor */ | |
115 | return switch_amode == 0; | |
116 | if (desc == 2) /* Secondary Segment Table Descriptor */ | |
117 | return tsk->thread.mm_segment.ar4; | |
118 | #ifdef CONFIG_S390_SWITCH_AMODE | |
119 | if (unlikely(desc == 1)) { /* STD determined via access register */ | |
120 | /* %a0 always indicates primary space. */ | |
121 | if (S390_lowcore.exc_access_id != 0) { | |
122 | save_access_regs(tsk->thread.acrs); | |
123 | /* | |
124 | * An alet of 0 indicates primary space. | |
125 | * An alet of 1 indicates secondary space. | |
126 | * Any other alet values generate an | |
127 | * alen-translation exception. | |
128 | */ | |
129 | if (tsk->thread.acrs[S390_lowcore.exc_access_id]) | |
130 | return tsk->thread.mm_segment.ar4; | |
131 | } | |
132 | } | |
133 | #endif | |
134 | /* Primary Segment Table Descriptor */ | |
135 | return switch_amode << s390_noexec; | |
1da177e4 LT |
136 | } |
137 | ||
138 | /* | |
139 | * Send SIGSEGV to task. This is an external routine | |
140 | * to keep the stack usage of do_page_fault small. | |
141 | */ | |
142 | static void do_sigsegv(struct pt_regs *regs, unsigned long error_code, | |
143 | int si_code, unsigned long address) | |
144 | { | |
145 | struct siginfo si; | |
146 | ||
147 | #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG) | |
148 | #if defined(CONFIG_SYSCTL) | |
149 | if (sysctl_userprocess_debug) | |
150 | #endif | |
151 | { | |
152 | printk("User process fault: interruption code 0x%lX\n", | |
153 | error_code); | |
154 | printk("failing address: %lX\n", address); | |
155 | show_regs(regs); | |
156 | } | |
157 | #endif | |
158 | si.si_signo = SIGSEGV; | |
159 | si.si_code = si_code; | |
d2c993d8 | 160 | si.si_addr = (void __user *) address; |
1da177e4 LT |
161 | force_sig_info(SIGSEGV, &si, current); |
162 | } | |
163 | ||
10c1031f MS |
164 | static void do_no_context(struct pt_regs *regs, unsigned long error_code, |
165 | unsigned long address) | |
166 | { | |
167 | const struct exception_table_entry *fixup; | |
168 | ||
169 | /* Are we prepared to handle this kernel fault? */ | |
170 | fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK); | |
171 | if (fixup) { | |
172 | regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; | |
173 | return; | |
174 | } | |
175 | ||
176 | /* | |
177 | * Oops. The kernel tried to access some bad page. We'll have to | |
178 | * terminate things with extreme prejudice. | |
179 | */ | |
180 | if (check_space(current) == 0) | |
181 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" | |
182 | " at virtual kernel address %p\n", (void *)address); | |
183 | else | |
184 | printk(KERN_ALERT "Unable to handle kernel paging request" | |
185 | " at virtual user address %p\n", (void *)address); | |
186 | ||
187 | die("Oops", regs, error_code); | |
188 | do_exit(SIGKILL); | |
189 | } | |
190 | ||
191 | static void do_low_address(struct pt_regs *regs, unsigned long error_code) | |
192 | { | |
193 | /* Low-address protection hit in kernel mode means | |
194 | NULL pointer write access in kernel mode. */ | |
195 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
196 | /* Low-address protection hit in user mode 'cannot happen'. */ | |
197 | die ("Low-address protection", regs, error_code); | |
198 | do_exit(SIGKILL); | |
199 | } | |
200 | ||
201 | do_no_context(regs, error_code, 0); | |
202 | } | |
203 | ||
10c1031f MS |
204 | static void do_sigbus(struct pt_regs *regs, unsigned long error_code, |
205 | unsigned long address) | |
206 | { | |
207 | struct task_struct *tsk = current; | |
208 | struct mm_struct *mm = tsk->mm; | |
209 | ||
210 | up_read(&mm->mmap_sem); | |
211 | /* | |
212 | * Send a sigbus, regardless of whether we were in kernel | |
213 | * or user mode. | |
214 | */ | |
215 | tsk->thread.prot_addr = address; | |
216 | tsk->thread.trap_no = error_code; | |
217 | force_sig(SIGBUS, tsk); | |
218 | ||
219 | /* Kernel mode? Handle exceptions or die */ | |
220 | if (!(regs->psw.mask & PSW_MASK_PSTATE)) | |
221 | do_no_context(regs, error_code, address); | |
222 | } | |
223 | ||
c1821c2e | 224 | #ifdef CONFIG_S390_EXEC_PROTECT |
be5ec363 MS |
225 | static int signal_return(struct mm_struct *mm, struct pt_regs *regs, |
226 | unsigned long address, unsigned long error_code) | |
c1821c2e | 227 | { |
be5ec363 | 228 | u16 instruction; |
490f03d6 HC |
229 | int rc; |
230 | #ifdef CONFIG_COMPAT | |
231 | int compat; | |
232 | #endif | |
be5ec363 MS |
233 | |
234 | pagefault_disable(); | |
235 | rc = __get_user(instruction, (u16 __user *) regs->psw.addr); | |
236 | pagefault_enable(); | |
237 | if (rc) | |
238 | return -EFAULT; | |
239 | ||
c1821c2e GS |
240 | up_read(&mm->mmap_sem); |
241 | clear_tsk_thread_flag(current, TIF_SINGLE_STEP); | |
242 | #ifdef CONFIG_COMPAT | |
7757591a | 243 | compat = is_compat_task(); |
be5ec363 | 244 | if (compat && instruction == 0x0a77) |
c2e8b853 | 245 | sys32_sigreturn(); |
be5ec363 | 246 | else if (compat && instruction == 0x0aad) |
c2e8b853 | 247 | sys32_rt_sigreturn(); |
c1821c2e | 248 | else |
be5ec363 MS |
249 | #endif |
250 | if (instruction == 0x0a77) | |
c2e8b853 | 251 | sys_sigreturn(); |
be5ec363 | 252 | else if (instruction == 0x0aad) |
c2e8b853 | 253 | sys_rt_sigreturn(); |
c1821c2e | 254 | else { |
c1821c2e GS |
255 | current->thread.prot_addr = address; |
256 | current->thread.trap_no = error_code; | |
257 | do_sigsegv(regs, error_code, SEGV_MAPERR, address); | |
258 | } | |
259 | return 0; | |
c1821c2e GS |
260 | } |
261 | #endif /* CONFIG_S390_EXEC_PROTECT */ | |
262 | ||
1da177e4 LT |
263 | /* |
264 | * This routine handles page faults. It determines the address, | |
265 | * and the problem, and then passes it off to one of the appropriate | |
266 | * routines. | |
267 | * | |
268 | * error_code: | |
269 | * 04 Protection -> Write-Protection (suprression) | |
270 | * 10 Segment translation -> Not present (nullification) | |
271 | * 11 Page translation -> Not present (nullification) | |
272 | * 3b Region third trans. -> Not present (nullification) | |
273 | */ | |
482b05dd | 274 | static inline void |
10c1031f | 275 | do_exception(struct pt_regs *regs, unsigned long error_code, int write) |
1da177e4 | 276 | { |
10c1031f MS |
277 | struct task_struct *tsk; |
278 | struct mm_struct *mm; | |
279 | struct vm_area_struct *vma; | |
280 | unsigned long address; | |
482b05dd | 281 | int space; |
10c1031f | 282 | int si_code; |
83c54070 | 283 | int fault; |
1da177e4 | 284 | |
33464e3b | 285 | if (notify_page_fault(regs, error_code)) |
4ba069b8 MG |
286 | return; |
287 | ||
10c1031f MS |
288 | tsk = current; |
289 | mm = tsk->mm; | |
1da177e4 | 290 | |
10c1031f MS |
291 | /* get the failing address and the affected space */ |
292 | address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; | |
482b05dd | 293 | space = check_space(tsk); |
1da177e4 LT |
294 | |
295 | /* | |
296 | * Verify that the fault happened in user space, that | |
297 | * we are not in an interrupt and that there is a | |
298 | * user context. | |
299 | */ | |
482b05dd GS |
300 | if (unlikely(space == 0 || in_atomic() || !mm)) |
301 | goto no_context; | |
1da177e4 LT |
302 | |
303 | /* | |
304 | * When we get here, the fault happened in the current | |
305 | * task's user address space, so we can switch on the | |
306 | * interrupts again and then search the VMAs | |
307 | */ | |
308 | local_irq_enable(); | |
cdd6c482 | 309 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address); |
10c1031f | 310 | down_read(&mm->mmap_sem); |
1da177e4 | 311 | |
482b05dd GS |
312 | si_code = SEGV_MAPERR; |
313 | vma = find_vma(mm, address); | |
314 | if (!vma) | |
315 | goto bad_area; | |
c1821c2e GS |
316 | |
317 | #ifdef CONFIG_S390_EXEC_PROTECT | |
482b05dd | 318 | if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC))) |
c1821c2e GS |
319 | if (!signal_return(mm, regs, address, error_code)) |
320 | /* | |
321 | * signal_return() has done an up_read(&mm->mmap_sem) | |
322 | * if it returns 0. | |
323 | */ | |
324 | return; | |
325 | #endif | |
326 | ||
10c1031f MS |
327 | if (vma->vm_start <= address) |
328 | goto good_area; | |
329 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
330 | goto bad_area; | |
331 | if (expand_stack(vma, address)) | |
332 | goto bad_area; | |
1da177e4 LT |
333 | /* |
334 | * Ok, we have a good vm_area for this memory access, so | |
335 | * we can handle it.. | |
336 | */ | |
337 | good_area: | |
338 | si_code = SEGV_ACCERR; | |
10c1031f | 339 | if (!write) { |
1da177e4 LT |
340 | /* page not present, check vm flags */ |
341 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) | |
342 | goto bad_area; | |
343 | } else { | |
344 | if (!(vma->vm_flags & VM_WRITE)) | |
345 | goto bad_area; | |
346 | } | |
347 | ||
53492b1d GS |
348 | if (is_vm_hugetlb_page(vma)) |
349 | address &= HPAGE_MASK; | |
1da177e4 LT |
350 | /* |
351 | * If for any reason at all we couldn't handle the fault, | |
352 | * make sure we exit gracefully rather than endlessly redo | |
353 | * the fault. | |
354 | */ | |
d06063cc | 355 | fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0); |
83c54070 NP |
356 | if (unlikely(fault & VM_FAULT_ERROR)) { |
357 | if (fault & VM_FAULT_OOM) { | |
59fa4392 HC |
358 | up_read(&mm->mmap_sem); |
359 | pagefault_out_of_memory(); | |
83c54070 NP |
360 | return; |
361 | } else if (fault & VM_FAULT_SIGBUS) { | |
362 | do_sigbus(regs, error_code, address); | |
363 | return; | |
364 | } | |
1da177e4 LT |
365 | BUG(); |
366 | } | |
bde69af2 | 367 | if (fault & VM_FAULT_MAJOR) { |
83c54070 | 368 | tsk->maj_flt++; |
cdd6c482 | 369 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, |
bde69af2 HC |
370 | regs, address); |
371 | } else { | |
83c54070 | 372 | tsk->min_flt++; |
cdd6c482 | 373 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, |
bde69af2 HC |
374 | regs, address); |
375 | } | |
1da177e4 LT |
376 | up_read(&mm->mmap_sem); |
377 | /* | |
378 | * The instruction that caused the program check will | |
379 | * be repeated. Don't signal single step via SIGTRAP. | |
380 | */ | |
482b05dd | 381 | clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP); |
1da177e4 LT |
382 | return; |
383 | ||
384 | /* | |
385 | * Something tried to access memory that isn't in our memory map.. | |
386 | * Fix it, but check if it's kernel or user first.. | |
387 | */ | |
388 | bad_area: | |
10c1031f | 389 | up_read(&mm->mmap_sem); |
1da177e4 | 390 | |
10c1031f MS |
391 | /* User mode accesses just cause a SIGSEGV */ |
392 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
393 | tsk->thread.prot_addr = address; | |
394 | tsk->thread.trap_no = error_code; | |
1da177e4 | 395 | do_sigsegv(regs, error_code, si_code, address); |
10c1031f | 396 | return; |
1da177e4 LT |
397 | } |
398 | ||
399 | no_context: | |
10c1031f | 400 | do_no_context(regs, error_code, address); |
1da177e4 LT |
401 | } |
402 | ||
482b05dd | 403 | void __kprobes do_protection_exception(struct pt_regs *regs, |
a806170e | 404 | long error_code) |
1da177e4 | 405 | { |
10c1031f | 406 | /* Protection exception is supressing, decrement psw address. */ |
1da177e4 | 407 | regs->psw.addr -= (error_code >> 16); |
10c1031f MS |
408 | /* |
409 | * Check for low-address protection. This needs to be treated | |
410 | * as a special case because the translation exception code | |
411 | * field is not guaranteed to contain valid data in this case. | |
412 | */ | |
413 | if (unlikely(!(S390_lowcore.trans_exc_code & 4))) { | |
414 | do_low_address(regs, error_code); | |
415 | return; | |
416 | } | |
1da177e4 LT |
417 | do_exception(regs, 4, 1); |
418 | } | |
419 | ||
a806170e | 420 | void __kprobes do_dat_exception(struct pt_regs *regs, long error_code) |
1da177e4 LT |
421 | { |
422 | do_exception(regs, error_code & 0xff, 0); | |
423 | } | |
424 | ||
6252d702 MS |
425 | #ifdef CONFIG_64BIT |
426 | void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code) | |
427 | { | |
428 | struct mm_struct *mm; | |
429 | struct vm_area_struct *vma; | |
430 | unsigned long address; | |
431 | int space; | |
432 | ||
433 | mm = current->mm; | |
434 | address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; | |
435 | space = check_space(current); | |
436 | ||
437 | if (unlikely(space == 0 || in_atomic() || !mm)) | |
438 | goto no_context; | |
439 | ||
440 | local_irq_enable(); | |
441 | ||
442 | down_read(&mm->mmap_sem); | |
443 | vma = find_vma(mm, address); | |
444 | up_read(&mm->mmap_sem); | |
445 | ||
446 | if (vma) { | |
447 | update_mm(mm, current); | |
448 | return; | |
449 | } | |
450 | ||
451 | /* User mode accesses just cause a SIGSEGV */ | |
452 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
453 | current->thread.prot_addr = address; | |
454 | current->thread.trap_no = error_code; | |
455 | do_sigsegv(regs, error_code, SEGV_MAPERR, address); | |
456 | return; | |
457 | } | |
458 | ||
459 | no_context: | |
460 | do_no_context(regs, error_code, address); | |
461 | } | |
462 | #endif | |
463 | ||
1da177e4 LT |
464 | #ifdef CONFIG_PFAULT |
465 | /* | |
466 | * 'pfault' pseudo page faults routines. | |
467 | */ | |
29b08d2b | 468 | static ext_int_info_t ext_int_pfault; |
1da177e4 LT |
469 | static int pfault_disable = 0; |
470 | ||
471 | static int __init nopfault(char *str) | |
472 | { | |
473 | pfault_disable = 1; | |
474 | return 1; | |
475 | } | |
476 | ||
477 | __setup("nopfault", nopfault); | |
478 | ||
479 | typedef struct { | |
480 | __u16 refdiagc; | |
481 | __u16 reffcode; | |
482 | __u16 refdwlen; | |
483 | __u16 refversn; | |
484 | __u64 refgaddr; | |
485 | __u64 refselmk; | |
486 | __u64 refcmpmk; | |
487 | __u64 reserved; | |
c41fbc69 | 488 | } __attribute__ ((packed, aligned(8))) pfault_refbk_t; |
1da177e4 LT |
489 | |
490 | int pfault_init(void) | |
491 | { | |
492 | pfault_refbk_t refbk = | |
493 | { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, | |
494 | __PF_RES_FIELD }; | |
495 | int rc; | |
496 | ||
29b08d2b | 497 | if (!MACHINE_IS_VM || pfault_disable) |
1da177e4 | 498 | return -1; |
94c12cc7 MS |
499 | asm volatile( |
500 | " diag %1,%0,0x258\n" | |
501 | "0: j 2f\n" | |
502 | "1: la %0,8\n" | |
1da177e4 | 503 | "2:\n" |
94c12cc7 MS |
504 | EX_TABLE(0b,1b) |
505 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
506 | __ctl_set_bit(0, 9); |
507 | return rc; | |
508 | } | |
509 | ||
510 | void pfault_fini(void) | |
511 | { | |
512 | pfault_refbk_t refbk = | |
513 | { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; | |
514 | ||
29b08d2b | 515 | if (!MACHINE_IS_VM || pfault_disable) |
1da177e4 LT |
516 | return; |
517 | __ctl_clear_bit(0,9); | |
94c12cc7 MS |
518 | asm volatile( |
519 | " diag %0,0,0x258\n" | |
1da177e4 | 520 | "0:\n" |
94c12cc7 MS |
521 | EX_TABLE(0b,0b) |
522 | : : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
523 | } |
524 | ||
2b67fc46 | 525 | static void pfault_interrupt(__u16 error_code) |
1da177e4 LT |
526 | { |
527 | struct task_struct *tsk; | |
528 | __u16 subcode; | |
529 | ||
530 | /* | |
531 | * Get the external interruption subcode & pfault | |
532 | * initial/completion signal bit. VM stores this | |
533 | * in the 'cpu address' field associated with the | |
534 | * external interrupt. | |
535 | */ | |
536 | subcode = S390_lowcore.cpu_addr; | |
537 | if ((subcode & 0xff00) != __SUBCODE_MASK) | |
538 | return; | |
539 | ||
540 | /* | |
541 | * Get the token (= address of the task structure of the affected task). | |
542 | */ | |
543 | tsk = *(struct task_struct **) __LC_PFAULT_INTPARM; | |
544 | ||
545 | if (subcode & 0x0080) { | |
546 | /* signal bit is set -> a page has been swapped in by VM */ | |
547 | if (xchg(&tsk->thread.pfault_wait, -1) != 0) { | |
548 | /* Initial interrupt was faster than the completion | |
549 | * interrupt. pfault_wait is valid. Set pfault_wait | |
550 | * back to zero and wake up the process. This can | |
551 | * safely be done because the task is still sleeping | |
b6d09449 | 552 | * and can't produce new pfaults. */ |
1da177e4 LT |
553 | tsk->thread.pfault_wait = 0; |
554 | wake_up_process(tsk); | |
b6d09449 | 555 | put_task_struct(tsk); |
1da177e4 LT |
556 | } |
557 | } else { | |
558 | /* signal bit not set -> a real page is missing. */ | |
b6d09449 | 559 | get_task_struct(tsk); |
1da177e4 LT |
560 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
561 | if (xchg(&tsk->thread.pfault_wait, 1) != 0) { | |
562 | /* Completion interrupt was faster than the initial | |
563 | * interrupt (swapped in a -1 for pfault_wait). Set | |
564 | * pfault_wait back to zero and exit. This can be | |
565 | * done safely because tsk is running in kernel | |
566 | * mode and can't produce new pfaults. */ | |
567 | tsk->thread.pfault_wait = 0; | |
568 | set_task_state(tsk, TASK_RUNNING); | |
b6d09449 | 569 | put_task_struct(tsk); |
1da177e4 LT |
570 | } else |
571 | set_tsk_need_resched(tsk); | |
572 | } | |
573 | } | |
1da177e4 | 574 | |
29b08d2b HC |
575 | void __init pfault_irq_init(void) |
576 | { | |
577 | if (!MACHINE_IS_VM) | |
578 | return; | |
579 | ||
580 | /* | |
581 | * Try to get pfault pseudo page faults going. | |
582 | */ | |
583 | if (register_early_external_interrupt(0x2603, pfault_interrupt, | |
584 | &ext_int_pfault) != 0) | |
585 | panic("Couldn't request external interrupt 0x2603"); | |
586 | ||
587 | if (pfault_init() == 0) | |
588 | return; | |
589 | ||
590 | /* Tough luck, no pfault. */ | |
591 | pfault_disable = 1; | |
592 | unregister_early_external_interrupt(0x2603, pfault_interrupt, | |
593 | &ext_int_pfault); | |
594 | } | |
595 | #endif |