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> |
cbb870c8 | 33 | #include <asm/asm-offsets.h> |
1da177e4 | 34 | #include <asm/system.h> |
1da177e4 | 35 | #include <asm/pgtable.h> |
29b08d2b | 36 | #include <asm/s390_ext.h> |
6252d702 | 37 | #include <asm/mmu_context.h> |
50d7280d | 38 | #include <asm/compat.h> |
a806170e | 39 | #include "../kernel/entry.h" |
1da177e4 | 40 | |
347a8dc3 | 41 | #ifndef CONFIG_64BIT |
1da177e4 | 42 | #define __FAIL_ADDR_MASK 0x7ffff000 |
1da177e4 LT |
43 | #define __SUBCODE_MASK 0x0200 |
44 | #define __PF_RES_FIELD 0ULL | |
347a8dc3 | 45 | #else /* CONFIG_64BIT */ |
1da177e4 | 46 | #define __FAIL_ADDR_MASK -4096L |
1da177e4 LT |
47 | #define __SUBCODE_MASK 0x0600 |
48 | #define __PF_RES_FIELD 0x8000000000000000ULL | |
347a8dc3 | 49 | #endif /* CONFIG_64BIT */ |
1da177e4 | 50 | |
50d7280d MS |
51 | #define VM_FAULT_BADCONTEXT 0x010000 |
52 | #define VM_FAULT_BADMAP 0x020000 | |
53 | #define VM_FAULT_BADACCESS 0x040000 | |
54 | ||
92f842ea MS |
55 | static unsigned long store_indication; |
56 | ||
57 | void fault_init(void) | |
58 | { | |
14375bc4 | 59 | if (test_facility(2) && test_facility(75)) |
92f842ea MS |
60 | store_indication = 0xc00; |
61 | } | |
62 | ||
7ecb344a | 63 | static inline int notify_page_fault(struct pt_regs *regs) |
10c1031f | 64 | { |
33464e3b CH |
65 | int ret = 0; |
66 | ||
67 | /* kprobe_running() needs smp_processor_id() */ | |
22e0a046 | 68 | if (kprobes_built_in() && !user_mode(regs)) { |
33464e3b CH |
69 | preempt_disable(); |
70 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
71 | ret = 1; | |
72 | preempt_enable(); | |
73 | } | |
33464e3b | 74 | return ret; |
4ba069b8 | 75 | } |
4ba069b8 | 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 | 102 | * Returns the address space associated with the fault. |
61365e13 | 103 | * Returns 0 for kernel space and 1 for user space. |
1da177e4 | 104 | */ |
61365e13 | 105 | static inline int user_space_fault(unsigned long trans_exc_code) |
1da177e4 LT |
106 | { |
107 | /* | |
61365e13 MS |
108 | * The lowest two bits of the translation exception |
109 | * identification indicate which paging table was used. | |
1da177e4 | 110 | */ |
61365e13 MS |
111 | trans_exc_code &= 3; |
112 | if (trans_exc_code == 2) | |
113 | /* Access via secondary space, set_fs setting decides */ | |
114 | return current->thread.mm_segment.ar4; | |
b11b5334 | 115 | if (user_mode == HOME_SPACE_MODE) |
61365e13 MS |
116 | /* User space if the access has been done via home space. */ |
117 | return trans_exc_code == 3; | |
118 | /* | |
119 | * If the user space is not the home space the kernel runs in home | |
120 | * space. Access via secondary space has already been covered, | |
121 | * access via primary space or access register is from user space | |
122 | * and access via home space is from the kernel. | |
123 | */ | |
124 | return trans_exc_code != 3; | |
1da177e4 LT |
125 | } |
126 | ||
ab3c68ee HC |
127 | static inline void report_user_fault(struct pt_regs *regs, long int_code, |
128 | int signr, unsigned long address) | |
129 | { | |
130 | if ((task_pid_nr(current) > 1) && !show_unhandled_signals) | |
131 | return; | |
132 | if (!unhandled_signal(current, signr)) | |
133 | return; | |
134 | if (!printk_ratelimit()) | |
135 | return; | |
136 | printk("User process fault: interruption code 0x%lX ", int_code); | |
137 | print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); | |
138 | printk("\n"); | |
139 | printk("failing address: %lX\n", address); | |
140 | show_regs(regs); | |
141 | } | |
142 | ||
1da177e4 LT |
143 | /* |
144 | * Send SIGSEGV to task. This is an external routine | |
145 | * to keep the stack usage of do_page_fault small. | |
146 | */ | |
50d7280d MS |
147 | static noinline void do_sigsegv(struct pt_regs *regs, long int_code, |
148 | int si_code, unsigned long trans_exc_code) | |
1da177e4 LT |
149 | { |
150 | struct siginfo si; | |
50d7280d | 151 | unsigned long address; |
1da177e4 | 152 | |
50d7280d MS |
153 | address = trans_exc_code & __FAIL_ADDR_MASK; |
154 | current->thread.prot_addr = address; | |
155 | current->thread.trap_no = int_code; | |
ab3c68ee | 156 | report_user_fault(regs, int_code, SIGSEGV, address); |
1da177e4 LT |
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 | ||
50d7280d MS |
163 | static noinline void do_no_context(struct pt_regs *regs, long int_code, |
164 | unsigned long trans_exc_code) | |
10c1031f MS |
165 | { |
166 | const struct exception_table_entry *fixup; | |
61365e13 | 167 | unsigned long address; |
10c1031f MS |
168 | |
169 | /* Are we prepared to handle this kernel fault? */ | |
50d7280d | 170 | fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); |
10c1031f MS |
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 | */ | |
61365e13 | 180 | address = trans_exc_code & __FAIL_ADDR_MASK; |
b11b5334 | 181 | if (!user_space_fault(trans_exc_code)) |
10c1031f MS |
182 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" |
183 | " at virtual kernel address %p\n", (void *)address); | |
184 | else | |
185 | printk(KERN_ALERT "Unable to handle kernel paging request" | |
186 | " at virtual user address %p\n", (void *)address); | |
187 | ||
50d7280d | 188 | die("Oops", regs, int_code); |
10c1031f MS |
189 | do_exit(SIGKILL); |
190 | } | |
191 | ||
50d7280d MS |
192 | static noinline void do_low_address(struct pt_regs *regs, long int_code, |
193 | unsigned long trans_exc_code) | |
10c1031f MS |
194 | { |
195 | /* Low-address protection hit in kernel mode means | |
196 | NULL pointer write access in kernel mode. */ | |
197 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
198 | /* Low-address protection hit in user mode 'cannot happen'. */ | |
50d7280d | 199 | die ("Low-address protection", regs, int_code); |
10c1031f MS |
200 | do_exit(SIGKILL); |
201 | } | |
202 | ||
50d7280d | 203 | do_no_context(regs, int_code, trans_exc_code); |
10c1031f MS |
204 | } |
205 | ||
50d7280d MS |
206 | static noinline void do_sigbus(struct pt_regs *regs, long int_code, |
207 | unsigned long trans_exc_code) | |
10c1031f MS |
208 | { |
209 | struct task_struct *tsk = current; | |
36bf9680 MS |
210 | unsigned long address; |
211 | struct siginfo si; | |
10c1031f | 212 | |
10c1031f MS |
213 | /* |
214 | * Send a sigbus, regardless of whether we were in kernel | |
215 | * or user mode. | |
216 | */ | |
36bf9680 MS |
217 | address = trans_exc_code & __FAIL_ADDR_MASK; |
218 | tsk->thread.prot_addr = address; | |
50d7280d | 219 | tsk->thread.trap_no = int_code; |
36bf9680 MS |
220 | si.si_signo = SIGBUS; |
221 | si.si_errno = 0; | |
222 | si.si_code = BUS_ADRERR; | |
223 | si.si_addr = (void __user *) address; | |
224 | force_sig_info(SIGBUS, &si, tsk); | |
10c1031f MS |
225 | } |
226 | ||
c1821c2e | 227 | #ifdef CONFIG_S390_EXEC_PROTECT |
50d7280d MS |
228 | static noinline int signal_return(struct pt_regs *regs, long int_code, |
229 | unsigned long trans_exc_code) | |
c1821c2e | 230 | { |
be5ec363 | 231 | u16 instruction; |
490f03d6 | 232 | int rc; |
be5ec363 | 233 | |
be5ec363 | 234 | rc = __get_user(instruction, (u16 __user *) regs->psw.addr); |
be5ec363 | 235 | |
50d7280d MS |
236 | if (!rc && instruction == 0x0a77) { |
237 | clear_tsk_thread_flag(current, TIF_SINGLE_STEP); | |
238 | if (is_compat_task()) | |
239 | sys32_sigreturn(); | |
240 | else | |
241 | sys_sigreturn(); | |
242 | } else if (!rc && instruction == 0x0aad) { | |
243 | clear_tsk_thread_flag(current, TIF_SINGLE_STEP); | |
244 | if (is_compat_task()) | |
245 | sys32_rt_sigreturn(); | |
246 | else | |
247 | sys_rt_sigreturn(); | |
248 | } else | |
249 | do_sigsegv(regs, int_code, SEGV_MAPERR, trans_exc_code); | |
c1821c2e | 250 | return 0; |
c1821c2e GS |
251 | } |
252 | #endif /* CONFIG_S390_EXEC_PROTECT */ | |
253 | ||
50d7280d MS |
254 | static noinline void do_fault_error(struct pt_regs *regs, long int_code, |
255 | unsigned long trans_exc_code, int fault) | |
256 | { | |
257 | int si_code; | |
258 | ||
259 | switch (fault) { | |
260 | case VM_FAULT_BADACCESS: | |
261 | #ifdef CONFIG_S390_EXEC_PROTECT | |
262 | if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY && | |
263 | (trans_exc_code & 3) == 0) { | |
264 | signal_return(regs, int_code, trans_exc_code); | |
265 | break; | |
266 | } | |
267 | #endif /* CONFIG_S390_EXEC_PROTECT */ | |
268 | case VM_FAULT_BADMAP: | |
269 | /* Bad memory access. Check if it is kernel or user space. */ | |
270 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
271 | /* User mode accesses just cause a SIGSEGV */ | |
272 | si_code = (fault == VM_FAULT_BADMAP) ? | |
273 | SEGV_MAPERR : SEGV_ACCERR; | |
274 | do_sigsegv(regs, int_code, si_code, trans_exc_code); | |
275 | return; | |
276 | } | |
277 | case VM_FAULT_BADCONTEXT: | |
278 | do_no_context(regs, int_code, trans_exc_code); | |
279 | break; | |
280 | default: /* fault & VM_FAULT_ERROR */ | |
281 | if (fault & VM_FAULT_OOM) | |
282 | pagefault_out_of_memory(); | |
283 | else if (fault & VM_FAULT_SIGBUS) { | |
50d7280d MS |
284 | /* Kernel mode? Handle exceptions or die */ |
285 | if (!(regs->psw.mask & PSW_MASK_PSTATE)) | |
286 | do_no_context(regs, int_code, trans_exc_code); | |
36bf9680 MS |
287 | else |
288 | do_sigbus(regs, int_code, trans_exc_code); | |
50d7280d MS |
289 | } else |
290 | BUG(); | |
291 | break; | |
292 | } | |
293 | } | |
294 | ||
1da177e4 LT |
295 | /* |
296 | * This routine handles page faults. It determines the address, | |
297 | * and the problem, and then passes it off to one of the appropriate | |
298 | * routines. | |
299 | * | |
50d7280d | 300 | * interruption code (int_code): |
1da177e4 LT |
301 | * 04 Protection -> Write-Protection (suprression) |
302 | * 10 Segment translation -> Not present (nullification) | |
303 | * 11 Page translation -> Not present (nullification) | |
304 | * 3b Region third trans. -> Not present (nullification) | |
305 | */ | |
1ab947de | 306 | static inline int do_exception(struct pt_regs *regs, int access, |
50d7280d | 307 | unsigned long trans_exc_code) |
1da177e4 | 308 | { |
10c1031f MS |
309 | struct task_struct *tsk; |
310 | struct mm_struct *mm; | |
311 | struct vm_area_struct *vma; | |
312 | unsigned long address; | |
92f842ea | 313 | int fault, write; |
1da177e4 | 314 | |
7ecb344a | 315 | if (notify_page_fault(regs)) |
50d7280d | 316 | return 0; |
4ba069b8 | 317 | |
10c1031f MS |
318 | tsk = current; |
319 | mm = tsk->mm; | |
1da177e4 | 320 | |
1da177e4 LT |
321 | /* |
322 | * Verify that the fault happened in user space, that | |
323 | * we are not in an interrupt and that there is a | |
324 | * user context. | |
325 | */ | |
50d7280d | 326 | fault = VM_FAULT_BADCONTEXT; |
61365e13 | 327 | if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) |
50d7280d | 328 | goto out; |
1da177e4 | 329 | |
61365e13 | 330 | address = trans_exc_code & __FAIL_ADDR_MASK; |
cdd6c482 | 331 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address); |
10c1031f | 332 | down_read(&mm->mmap_sem); |
1da177e4 | 333 | |
50d7280d | 334 | fault = VM_FAULT_BADMAP; |
482b05dd GS |
335 | vma = find_vma(mm, address); |
336 | if (!vma) | |
50d7280d | 337 | goto out_up; |
c1821c2e | 338 | |
50d7280d MS |
339 | if (unlikely(vma->vm_start > address)) { |
340 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
341 | goto out_up; | |
342 | if (expand_stack(vma, address)) | |
343 | goto out_up; | |
344 | } | |
345 | ||
346 | /* | |
347 | * Ok, we have a good vm_area for this memory access, so | |
348 | * we can handle it.. | |
349 | */ | |
350 | fault = VM_FAULT_BADACCESS; | |
1ab947de | 351 | if (unlikely(!(vma->vm_flags & access))) |
50d7280d | 352 | goto out_up; |
1da177e4 | 353 | |
53492b1d GS |
354 | if (is_vm_hugetlb_page(vma)) |
355 | address &= HPAGE_MASK; | |
1da177e4 LT |
356 | /* |
357 | * If for any reason at all we couldn't handle the fault, | |
358 | * make sure we exit gracefully rather than endlessly redo | |
359 | * the fault. | |
360 | */ | |
92f842ea MS |
361 | write = (access == VM_WRITE || |
362 | (trans_exc_code & store_indication) == 0x400) ? | |
363 | FAULT_FLAG_WRITE : 0; | |
364 | fault = handle_mm_fault(mm, vma, address, write); | |
50d7280d MS |
365 | if (unlikely(fault & VM_FAULT_ERROR)) |
366 | goto out_up; | |
367 | ||
bde69af2 | 368 | if (fault & VM_FAULT_MAJOR) { |
83c54070 | 369 | tsk->maj_flt++; |
cdd6c482 | 370 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, |
bde69af2 HC |
371 | regs, address); |
372 | } else { | |
83c54070 | 373 | tsk->min_flt++; |
cdd6c482 | 374 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, |
bde69af2 HC |
375 | regs, address); |
376 | } | |
1da177e4 LT |
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); |
50d7280d MS |
382 | fault = 0; |
383 | out_up: | |
10c1031f | 384 | up_read(&mm->mmap_sem); |
50d7280d MS |
385 | out: |
386 | return fault; | |
1da177e4 LT |
387 | } |
388 | ||
1e54622e MS |
389 | void __kprobes do_protection_exception(struct pt_regs *regs, long pgm_int_code, |
390 | unsigned long trans_exc_code) | |
1da177e4 | 391 | { |
50d7280d | 392 | int fault; |
61365e13 | 393 | |
10c1031f | 394 | /* Protection exception is supressing, decrement psw address. */ |
1e54622e | 395 | regs->psw.addr -= (pgm_int_code >> 16); |
10c1031f MS |
396 | /* |
397 | * Check for low-address protection. This needs to be treated | |
398 | * as a special case because the translation exception code | |
399 | * field is not guaranteed to contain valid data in this case. | |
400 | */ | |
61365e13 | 401 | if (unlikely(!(trans_exc_code & 4))) { |
1e54622e | 402 | do_low_address(regs, pgm_int_code, trans_exc_code); |
10c1031f MS |
403 | return; |
404 | } | |
1ab947de | 405 | fault = do_exception(regs, VM_WRITE, trans_exc_code); |
50d7280d MS |
406 | if (unlikely(fault)) |
407 | do_fault_error(regs, 4, trans_exc_code, fault); | |
1da177e4 LT |
408 | } |
409 | ||
1e54622e MS |
410 | void __kprobes do_dat_exception(struct pt_regs *regs, long pgm_int_code, |
411 | unsigned long trans_exc_code) | |
1da177e4 | 412 | { |
1ab947de | 413 | int access, fault; |
50d7280d | 414 | |
1ab947de MS |
415 | access = VM_READ | VM_EXEC | VM_WRITE; |
416 | #ifdef CONFIG_S390_EXEC_PROTECT | |
417 | if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY && | |
418 | (trans_exc_code & 3) == 0) | |
419 | access = VM_EXEC; | |
420 | #endif | |
421 | fault = do_exception(regs, access, trans_exc_code); | |
50d7280d | 422 | if (unlikely(fault)) |
1e54622e | 423 | do_fault_error(regs, pgm_int_code & 255, trans_exc_code, fault); |
1da177e4 LT |
424 | } |
425 | ||
6252d702 | 426 | #ifdef CONFIG_64BIT |
1e54622e MS |
427 | void __kprobes do_asce_exception(struct pt_regs *regs, long pgm_int_code, |
428 | unsigned long trans_exc_code) | |
6252d702 | 429 | { |
50d7280d | 430 | struct mm_struct *mm = current->mm; |
6252d702 | 431 | struct vm_area_struct *vma; |
6252d702 | 432 | |
61365e13 | 433 | if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) |
6252d702 MS |
434 | goto no_context; |
435 | ||
6252d702 | 436 | down_read(&mm->mmap_sem); |
50d7280d | 437 | vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK); |
6252d702 MS |
438 | up_read(&mm->mmap_sem); |
439 | ||
440 | if (vma) { | |
441 | update_mm(mm, current); | |
442 | return; | |
443 | } | |
444 | ||
445 | /* User mode accesses just cause a SIGSEGV */ | |
446 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
1e54622e | 447 | do_sigsegv(regs, pgm_int_code, SEGV_MAPERR, trans_exc_code); |
6252d702 MS |
448 | return; |
449 | } | |
450 | ||
451 | no_context: | |
1e54622e | 452 | do_no_context(regs, pgm_int_code, trans_exc_code); |
6252d702 MS |
453 | } |
454 | #endif | |
455 | ||
1e54622e | 456 | int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) |
6c1e3e79 GS |
457 | { |
458 | struct pt_regs regs; | |
459 | int access, fault; | |
460 | ||
461 | regs.psw.mask = psw_kernel_bits; | |
462 | if (!irqs_disabled()) | |
463 | regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; | |
464 | regs.psw.addr = (unsigned long) __builtin_return_address(0); | |
465 | regs.psw.addr |= PSW_ADDR_AMODE; | |
466 | uaddr &= PAGE_MASK; | |
1e54622e | 467 | access = write ? VM_WRITE : VM_READ; |
6c1e3e79 GS |
468 | fault = do_exception(®s, access, uaddr | 2); |
469 | if (unlikely(fault)) { | |
470 | if (fault & VM_FAULT_OOM) { | |
471 | pagefault_out_of_memory(); | |
472 | fault = 0; | |
473 | } else if (fault & VM_FAULT_SIGBUS) | |
1e54622e | 474 | do_sigbus(®s, pgm_int_code, uaddr); |
6c1e3e79 GS |
475 | } |
476 | return fault ? -EFAULT : 0; | |
477 | } | |
478 | ||
1da177e4 LT |
479 | #ifdef CONFIG_PFAULT |
480 | /* | |
481 | * 'pfault' pseudo page faults routines. | |
482 | */ | |
29b08d2b | 483 | static ext_int_info_t ext_int_pfault; |
1da177e4 LT |
484 | static int pfault_disable = 0; |
485 | ||
486 | static int __init nopfault(char *str) | |
487 | { | |
488 | pfault_disable = 1; | |
489 | return 1; | |
490 | } | |
491 | ||
492 | __setup("nopfault", nopfault); | |
493 | ||
494 | typedef struct { | |
495 | __u16 refdiagc; | |
496 | __u16 reffcode; | |
497 | __u16 refdwlen; | |
498 | __u16 refversn; | |
499 | __u64 refgaddr; | |
500 | __u64 refselmk; | |
501 | __u64 refcmpmk; | |
502 | __u64 reserved; | |
c41fbc69 | 503 | } __attribute__ ((packed, aligned(8))) pfault_refbk_t; |
1da177e4 LT |
504 | |
505 | int pfault_init(void) | |
506 | { | |
507 | pfault_refbk_t refbk = | |
508 | { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, | |
509 | __PF_RES_FIELD }; | |
510 | int rc; | |
511 | ||
29b08d2b | 512 | if (!MACHINE_IS_VM || pfault_disable) |
1da177e4 | 513 | return -1; |
94c12cc7 MS |
514 | asm volatile( |
515 | " diag %1,%0,0x258\n" | |
516 | "0: j 2f\n" | |
517 | "1: la %0,8\n" | |
1da177e4 | 518 | "2:\n" |
94c12cc7 MS |
519 | EX_TABLE(0b,1b) |
520 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
521 | __ctl_set_bit(0, 9); |
522 | return rc; | |
523 | } | |
524 | ||
525 | void pfault_fini(void) | |
526 | { | |
527 | pfault_refbk_t refbk = | |
528 | { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; | |
529 | ||
29b08d2b | 530 | if (!MACHINE_IS_VM || pfault_disable) |
1da177e4 LT |
531 | return; |
532 | __ctl_clear_bit(0,9); | |
94c12cc7 MS |
533 | asm volatile( |
534 | " diag %0,0,0x258\n" | |
1da177e4 | 535 | "0:\n" |
94c12cc7 MS |
536 | EX_TABLE(0b,0b) |
537 | : : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
538 | } |
539 | ||
f6649a7e MS |
540 | static void pfault_interrupt(unsigned int ext_int_code, |
541 | unsigned int param32, unsigned long param64) | |
1da177e4 LT |
542 | { |
543 | struct task_struct *tsk; | |
544 | __u16 subcode; | |
545 | ||
546 | /* | |
547 | * Get the external interruption subcode & pfault | |
548 | * initial/completion signal bit. VM stores this | |
549 | * in the 'cpu address' field associated with the | |
550 | * external interrupt. | |
551 | */ | |
f6649a7e | 552 | subcode = ext_int_code >> 16; |
1da177e4 LT |
553 | if ((subcode & 0xff00) != __SUBCODE_MASK) |
554 | return; | |
555 | ||
556 | /* | |
557 | * Get the token (= address of the task structure of the affected task). | |
558 | */ | |
f6649a7e MS |
559 | #ifdef CONFIG_64BIT |
560 | tsk = *(struct task_struct **) param64; | |
561 | #else | |
562 | tsk = *(struct task_struct **) param32; | |
563 | #endif | |
1da177e4 LT |
564 | |
565 | if (subcode & 0x0080) { | |
566 | /* signal bit is set -> a page has been swapped in by VM */ | |
567 | if (xchg(&tsk->thread.pfault_wait, -1) != 0) { | |
568 | /* Initial interrupt was faster than the completion | |
569 | * interrupt. pfault_wait is valid. Set pfault_wait | |
570 | * back to zero and wake up the process. This can | |
571 | * safely be done because the task is still sleeping | |
b6d09449 | 572 | * and can't produce new pfaults. */ |
1da177e4 LT |
573 | tsk->thread.pfault_wait = 0; |
574 | wake_up_process(tsk); | |
b6d09449 | 575 | put_task_struct(tsk); |
1da177e4 LT |
576 | } |
577 | } else { | |
578 | /* signal bit not set -> a real page is missing. */ | |
b6d09449 | 579 | get_task_struct(tsk); |
1da177e4 LT |
580 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
581 | if (xchg(&tsk->thread.pfault_wait, 1) != 0) { | |
582 | /* Completion interrupt was faster than the initial | |
583 | * interrupt (swapped in a -1 for pfault_wait). Set | |
584 | * pfault_wait back to zero and exit. This can be | |
585 | * done safely because tsk is running in kernel | |
586 | * mode and can't produce new pfaults. */ | |
587 | tsk->thread.pfault_wait = 0; | |
588 | set_task_state(tsk, TASK_RUNNING); | |
b6d09449 | 589 | put_task_struct(tsk); |
1da177e4 LT |
590 | } else |
591 | set_tsk_need_resched(tsk); | |
592 | } | |
593 | } | |
1da177e4 | 594 | |
29b08d2b HC |
595 | void __init pfault_irq_init(void) |
596 | { | |
597 | if (!MACHINE_IS_VM) | |
598 | return; | |
599 | ||
600 | /* | |
601 | * Try to get pfault pseudo page faults going. | |
602 | */ | |
603 | if (register_early_external_interrupt(0x2603, pfault_interrupt, | |
604 | &ext_int_pfault) != 0) | |
605 | panic("Couldn't request external interrupt 0x2603"); | |
606 | ||
607 | if (pfault_init() == 0) | |
608 | return; | |
609 | ||
610 | /* Tough luck, no pfault. */ | |
611 | pfault_disable = 1; | |
612 | unregister_early_external_interrupt(0x2603, pfault_interrupt, | |
613 | &ext_int_pfault); | |
614 | } | |
615 | #endif |