Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 | 2 | * S390 version |
a53c8fab | 3 | * Copyright IBM Corp. 1999 |
1da177e4 LT |
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 | ||
052ff461 | 11 | #include <linux/kernel_stat.h> |
cdd6c482 | 12 | #include <linux/perf_event.h> |
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> | |
7757591a | 22 | #include <linux/compat.h> |
1da177e4 | 23 | #include <linux/smp.h> |
1eeb66a1 | 24 | #include <linux/kdebug.h> |
1da177e4 LT |
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> |
cbb870c8 | 32 | #include <asm/asm-offsets.h> |
1da177e4 | 33 | #include <asm/pgtable.h> |
d7b250e2 | 34 | #include <asm/irq.h> |
6252d702 | 35 | #include <asm/mmu_context.h> |
a0616cde | 36 | #include <asm/facility.h> |
a806170e | 37 | #include "../kernel/entry.h" |
1da177e4 | 38 | |
347a8dc3 | 39 | #ifndef CONFIG_64BIT |
1da177e4 | 40 | #define __FAIL_ADDR_MASK 0x7ffff000 |
1da177e4 LT |
41 | #define __SUBCODE_MASK 0x0200 |
42 | #define __PF_RES_FIELD 0ULL | |
347a8dc3 | 43 | #else /* CONFIG_64BIT */ |
1da177e4 | 44 | #define __FAIL_ADDR_MASK -4096L |
1da177e4 LT |
45 | #define __SUBCODE_MASK 0x0600 |
46 | #define __PF_RES_FIELD 0x8000000000000000ULL | |
347a8dc3 | 47 | #endif /* CONFIG_64BIT */ |
1da177e4 | 48 | |
50d7280d MS |
49 | #define VM_FAULT_BADCONTEXT 0x010000 |
50 | #define VM_FAULT_BADMAP 0x020000 | |
51 | #define VM_FAULT_BADACCESS 0x040000 | |
a4f32bdb | 52 | #define VM_FAULT_SIGNAL 0x080000 |
50d7280d | 53 | |
a4f32bdb | 54 | static unsigned long store_indication __read_mostly; |
92f842ea | 55 | |
a4f32bdb HC |
56 | #ifdef CONFIG_64BIT |
57 | static int __init fault_init(void) | |
92f842ea | 58 | { |
a4f32bdb | 59 | if (test_facility(75)) |
92f842ea | 60 | store_indication = 0xc00; |
a4f32bdb | 61 | return 0; |
92f842ea | 62 | } |
a4f32bdb HC |
63 | early_initcall(fault_init); |
64 | #endif | |
92f842ea | 65 | |
7ecb344a | 66 | static inline int notify_page_fault(struct pt_regs *regs) |
10c1031f | 67 | { |
33464e3b CH |
68 | int ret = 0; |
69 | ||
70 | /* kprobe_running() needs smp_processor_id() */ | |
22e0a046 | 71 | if (kprobes_built_in() && !user_mode(regs)) { |
33464e3b CH |
72 | preempt_disable(); |
73 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
74 | ret = 1; | |
75 | preempt_enable(); | |
76 | } | |
33464e3b | 77 | return ret; |
4ba069b8 | 78 | } |
4ba069b8 | 79 | |
1da177e4 LT |
80 | |
81 | /* | |
82 | * Unlock any spinlocks which will prevent us from getting the | |
cefc8be8 | 83 | * message out. |
1da177e4 LT |
84 | */ |
85 | void bust_spinlocks(int yes) | |
86 | { | |
87 | if (yes) { | |
88 | oops_in_progress = 1; | |
89 | } else { | |
90 | int loglevel_save = console_loglevel; | |
91 | console_unblank(); | |
92 | oops_in_progress = 0; | |
93 | /* | |
94 | * OK, the message is on the console. Now we call printk() | |
95 | * without oops_in_progress set so that printk will give klogd | |
96 | * a poke. Hold onto your hats... | |
97 | */ | |
98 | console_loglevel = 15; | |
99 | printk(" "); | |
100 | console_loglevel = loglevel_save; | |
101 | } | |
102 | } | |
103 | ||
104 | /* | |
482b05dd | 105 | * Returns the address space associated with the fault. |
61365e13 | 106 | * Returns 0 for kernel space and 1 for user space. |
1da177e4 | 107 | */ |
61365e13 | 108 | static inline int user_space_fault(unsigned long trans_exc_code) |
1da177e4 LT |
109 | { |
110 | /* | |
61365e13 MS |
111 | * The lowest two bits of the translation exception |
112 | * identification indicate which paging table was used. | |
1da177e4 | 113 | */ |
61365e13 MS |
114 | trans_exc_code &= 3; |
115 | if (trans_exc_code == 2) | |
116 | /* Access via secondary space, set_fs setting decides */ | |
117 | return current->thread.mm_segment.ar4; | |
d1b0d842 | 118 | if (s390_user_mode == HOME_SPACE_MODE) |
61365e13 MS |
119 | /* User space if the access has been done via home space. */ |
120 | return trans_exc_code == 3; | |
121 | /* | |
122 | * If the user space is not the home space the kernel runs in home | |
123 | * space. Access via secondary space has already been covered, | |
124 | * access via primary space or access register is from user space | |
125 | * and access via home space is from the kernel. | |
126 | */ | |
127 | return trans_exc_code != 3; | |
1da177e4 LT |
128 | } |
129 | ||
aa33c8cb | 130 | static inline void report_user_fault(struct pt_regs *regs, long signr) |
ab3c68ee HC |
131 | { |
132 | if ((task_pid_nr(current) > 1) && !show_unhandled_signals) | |
133 | return; | |
134 | if (!unhandled_signal(current, signr)) | |
135 | return; | |
136 | if (!printk_ratelimit()) | |
137 | return; | |
aa33c8cb MS |
138 | printk(KERN_ALERT "User process fault: interruption code 0x%X ", |
139 | regs->int_code); | |
ab3c68ee | 140 | print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); |
aa33c8cb MS |
141 | printk(KERN_CONT "\n"); |
142 | printk(KERN_ALERT "failing address: %lX\n", | |
143 | regs->int_parm_long & __FAIL_ADDR_MASK); | |
ab3c68ee HC |
144 | show_regs(regs); |
145 | } | |
146 | ||
1da177e4 LT |
147 | /* |
148 | * Send SIGSEGV to task. This is an external routine | |
149 | * to keep the stack usage of do_page_fault small. | |
150 | */ | |
aa33c8cb | 151 | static noinline void do_sigsegv(struct pt_regs *regs, int si_code) |
1da177e4 LT |
152 | { |
153 | struct siginfo si; | |
154 | ||
aa33c8cb | 155 | report_user_fault(regs, SIGSEGV); |
1da177e4 LT |
156 | si.si_signo = SIGSEGV; |
157 | si.si_code = si_code; | |
aa33c8cb | 158 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
1da177e4 LT |
159 | force_sig_info(SIGSEGV, &si, current); |
160 | } | |
161 | ||
aa33c8cb | 162 | static noinline void do_no_context(struct pt_regs *regs) |
10c1031f MS |
163 | { |
164 | const struct exception_table_entry *fixup; | |
61365e13 | 165 | unsigned long address; |
10c1031f MS |
166 | |
167 | /* Are we prepared to handle this kernel fault? */ | |
50d7280d | 168 | fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); |
10c1031f | 169 | if (fixup) { |
eb608fb3 | 170 | regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; |
10c1031f MS |
171 | return; |
172 | } | |
173 | ||
174 | /* | |
175 | * Oops. The kernel tried to access some bad page. We'll have to | |
176 | * terminate things with extreme prejudice. | |
177 | */ | |
aa33c8cb MS |
178 | address = regs->int_parm_long & __FAIL_ADDR_MASK; |
179 | if (!user_space_fault(regs->int_parm_long)) | |
10c1031f MS |
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 | ||
aa33c8cb | 186 | die(regs, "Oops"); |
10c1031f MS |
187 | do_exit(SIGKILL); |
188 | } | |
189 | ||
aa33c8cb | 190 | static noinline void do_low_address(struct pt_regs *regs) |
10c1031f MS |
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'. */ | |
aa33c8cb | 196 | die (regs, "Low-address protection"); |
10c1031f MS |
197 | do_exit(SIGKILL); |
198 | } | |
199 | ||
aa33c8cb | 200 | do_no_context(regs); |
10c1031f MS |
201 | } |
202 | ||
aa33c8cb | 203 | static noinline void do_sigbus(struct pt_regs *regs) |
10c1031f MS |
204 | { |
205 | struct task_struct *tsk = current; | |
36bf9680 | 206 | struct siginfo si; |
10c1031f | 207 | |
10c1031f MS |
208 | /* |
209 | * Send a sigbus, regardless of whether we were in kernel | |
210 | * or user mode. | |
211 | */ | |
36bf9680 MS |
212 | si.si_signo = SIGBUS; |
213 | si.si_errno = 0; | |
214 | si.si_code = BUS_ADRERR; | |
aa33c8cb | 215 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
36bf9680 | 216 | force_sig_info(SIGBUS, &si, tsk); |
10c1031f MS |
217 | } |
218 | ||
aa33c8cb | 219 | static noinline void do_fault_error(struct pt_regs *regs, int fault) |
50d7280d MS |
220 | { |
221 | int si_code; | |
222 | ||
223 | switch (fault) { | |
224 | case VM_FAULT_BADACCESS: | |
50d7280d MS |
225 | case VM_FAULT_BADMAP: |
226 | /* Bad memory access. Check if it is kernel or user space. */ | |
7d256175 | 227 | if (user_mode(regs)) { |
50d7280d MS |
228 | /* User mode accesses just cause a SIGSEGV */ |
229 | si_code = (fault == VM_FAULT_BADMAP) ? | |
230 | SEGV_MAPERR : SEGV_ACCERR; | |
aa33c8cb | 231 | do_sigsegv(regs, si_code); |
50d7280d MS |
232 | return; |
233 | } | |
234 | case VM_FAULT_BADCONTEXT: | |
aa33c8cb | 235 | do_no_context(regs); |
50d7280d | 236 | break; |
f2c76e3b HC |
237 | case VM_FAULT_SIGNAL: |
238 | if (!user_mode(regs)) | |
239 | do_no_context(regs); | |
240 | break; | |
50d7280d | 241 | default: /* fault & VM_FAULT_ERROR */ |
99583181 | 242 | if (fault & VM_FAULT_OOM) { |
7d256175 | 243 | if (!user_mode(regs)) |
aa33c8cb | 244 | do_no_context(regs); |
99583181 HC |
245 | else |
246 | pagefault_out_of_memory(); | |
247 | } else if (fault & VM_FAULT_SIGBUS) { | |
50d7280d | 248 | /* Kernel mode? Handle exceptions or die */ |
7d256175 | 249 | if (!user_mode(regs)) |
aa33c8cb | 250 | do_no_context(regs); |
36bf9680 | 251 | else |
aa33c8cb | 252 | do_sigbus(regs); |
50d7280d MS |
253 | } else |
254 | BUG(); | |
255 | break; | |
256 | } | |
257 | } | |
258 | ||
1da177e4 LT |
259 | /* |
260 | * This routine handles page faults. It determines the address, | |
261 | * and the problem, and then passes it off to one of the appropriate | |
262 | * routines. | |
263 | * | |
50d7280d | 264 | * interruption code (int_code): |
1da177e4 LT |
265 | * 04 Protection -> Write-Protection (suprression) |
266 | * 10 Segment translation -> Not present (nullification) | |
267 | * 11 Page translation -> Not present (nullification) | |
268 | * 3b Region third trans. -> Not present (nullification) | |
269 | */ | |
aa33c8cb | 270 | static inline int do_exception(struct pt_regs *regs, int access) |
1da177e4 | 271 | { |
10c1031f MS |
272 | struct task_struct *tsk; |
273 | struct mm_struct *mm; | |
274 | struct vm_area_struct *vma; | |
aa33c8cb | 275 | unsigned long trans_exc_code; |
10c1031f | 276 | unsigned long address; |
33ce6140 HC |
277 | unsigned int flags; |
278 | int fault; | |
1da177e4 | 279 | |
39efd4ec MS |
280 | tsk = current; |
281 | /* | |
282 | * The instruction that caused the program check has | |
283 | * been nullified. Don't signal single step via SIGTRAP. | |
284 | */ | |
285 | clear_tsk_thread_flag(tsk, TIF_PER_TRAP); | |
286 | ||
7ecb344a | 287 | if (notify_page_fault(regs)) |
50d7280d | 288 | return 0; |
4ba069b8 | 289 | |
10c1031f | 290 | mm = tsk->mm; |
aa33c8cb | 291 | trans_exc_code = regs->int_parm_long; |
1da177e4 | 292 | |
1da177e4 LT |
293 | /* |
294 | * Verify that the fault happened in user space, that | |
295 | * we are not in an interrupt and that there is a | |
296 | * user context. | |
297 | */ | |
50d7280d | 298 | fault = VM_FAULT_BADCONTEXT; |
61365e13 | 299 | if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) |
50d7280d | 300 | goto out; |
1da177e4 | 301 | |
61365e13 | 302 | address = trans_exc_code & __FAIL_ADDR_MASK; |
a8b0ca17 | 303 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
f2c76e3b | 304 | flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
33ce6140 HC |
305 | if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) |
306 | flags |= FAULT_FLAG_WRITE; | |
10c1031f | 307 | down_read(&mm->mmap_sem); |
1da177e4 | 308 | |
e5992f2e | 309 | #ifdef CONFIG_PGSTE |
5e8010cb | 310 | if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { |
499069e1 | 311 | address = __gmap_fault(address, |
e5992f2e MS |
312 | (struct gmap *) S390_lowcore.gmap); |
313 | if (address == -EFAULT) { | |
314 | fault = VM_FAULT_BADMAP; | |
315 | goto out_up; | |
316 | } | |
317 | if (address == -ENOMEM) { | |
318 | fault = VM_FAULT_OOM; | |
319 | goto out_up; | |
320 | } | |
321 | } | |
322 | #endif | |
323 | ||
324 | retry: | |
50d7280d | 325 | fault = VM_FAULT_BADMAP; |
482b05dd GS |
326 | vma = find_vma(mm, address); |
327 | if (!vma) | |
50d7280d | 328 | goto out_up; |
c1821c2e | 329 | |
50d7280d MS |
330 | if (unlikely(vma->vm_start > address)) { |
331 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
332 | goto out_up; | |
333 | if (expand_stack(vma, address)) | |
334 | goto out_up; | |
335 | } | |
336 | ||
337 | /* | |
338 | * Ok, we have a good vm_area for this memory access, so | |
339 | * we can handle it.. | |
340 | */ | |
341 | fault = VM_FAULT_BADACCESS; | |
1ab947de | 342 | if (unlikely(!(vma->vm_flags & access))) |
50d7280d | 343 | goto out_up; |
1da177e4 | 344 | |
53492b1d GS |
345 | if (is_vm_hugetlb_page(vma)) |
346 | address &= HPAGE_MASK; | |
1da177e4 LT |
347 | /* |
348 | * If for any reason at all we couldn't handle the fault, | |
349 | * make sure we exit gracefully rather than endlessly redo | |
350 | * the fault. | |
351 | */ | |
33ce6140 | 352 | fault = handle_mm_fault(mm, vma, address, flags); |
f2c76e3b HC |
353 | /* No reason to continue if interrupted by SIGKILL. */ |
354 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { | |
355 | fault = VM_FAULT_SIGNAL; | |
356 | goto out; | |
357 | } | |
50d7280d MS |
358 | if (unlikely(fault & VM_FAULT_ERROR)) |
359 | goto out_up; | |
360 | ||
33ce6140 HC |
361 | /* |
362 | * Major/minor page fault accounting is only done on the | |
363 | * initial attempt. If we go through a retry, it is extremely | |
364 | * likely that the page will be found in page cache at that point. | |
365 | */ | |
366 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
367 | if (fault & VM_FAULT_MAJOR) { | |
368 | tsk->maj_flt++; | |
a8b0ca17 | 369 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, |
33ce6140 HC |
370 | regs, address); |
371 | } else { | |
372 | tsk->min_flt++; | |
a8b0ca17 | 373 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, |
33ce6140 HC |
374 | regs, address); |
375 | } | |
376 | if (fault & VM_FAULT_RETRY) { | |
377 | /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk | |
378 | * of starvation. */ | |
379 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
45cac65b | 380 | flags |= FAULT_FLAG_TRIED; |
e5992f2e | 381 | down_read(&mm->mmap_sem); |
33ce6140 HC |
382 | goto retry; |
383 | } | |
bde69af2 | 384 | } |
50d7280d MS |
385 | fault = 0; |
386 | out_up: | |
10c1031f | 387 | up_read(&mm->mmap_sem); |
50d7280d MS |
388 | out: |
389 | return fault; | |
1da177e4 LT |
390 | } |
391 | ||
aa33c8cb | 392 | void __kprobes do_protection_exception(struct pt_regs *regs) |
1da177e4 | 393 | { |
aa33c8cb | 394 | unsigned long trans_exc_code; |
50d7280d | 395 | int fault; |
61365e13 | 396 | |
aa33c8cb | 397 | trans_exc_code = regs->int_parm_long; |
25985edc | 398 | /* Protection exception is suppressing, decrement psw address. */ |
aa33c8cb | 399 | regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); |
10c1031f MS |
400 | /* |
401 | * Check for low-address protection. This needs to be treated | |
402 | * as a special case because the translation exception code | |
403 | * field is not guaranteed to contain valid data in this case. | |
404 | */ | |
61365e13 | 405 | if (unlikely(!(trans_exc_code & 4))) { |
aa33c8cb | 406 | do_low_address(regs); |
10c1031f MS |
407 | return; |
408 | } | |
aa33c8cb | 409 | fault = do_exception(regs, VM_WRITE); |
50d7280d | 410 | if (unlikely(fault)) |
aa33c8cb | 411 | do_fault_error(regs, fault); |
1da177e4 LT |
412 | } |
413 | ||
aa33c8cb | 414 | void __kprobes do_dat_exception(struct pt_regs *regs) |
1da177e4 | 415 | { |
1ab947de | 416 | int access, fault; |
50d7280d | 417 | |
1ab947de | 418 | access = VM_READ | VM_EXEC | VM_WRITE; |
aa33c8cb | 419 | fault = do_exception(regs, access); |
50d7280d | 420 | if (unlikely(fault)) |
aa33c8cb | 421 | do_fault_error(regs, fault); |
1da177e4 LT |
422 | } |
423 | ||
6252d702 | 424 | #ifdef CONFIG_64BIT |
aa33c8cb | 425 | void __kprobes do_asce_exception(struct pt_regs *regs) |
6252d702 | 426 | { |
50d7280d | 427 | struct mm_struct *mm = current->mm; |
6252d702 | 428 | struct vm_area_struct *vma; |
aa33c8cb | 429 | unsigned long trans_exc_code; |
6252d702 | 430 | |
39efd4ec MS |
431 | /* |
432 | * The instruction that caused the program check has | |
433 | * been nullified. Don't signal single step via SIGTRAP. | |
434 | */ | |
435 | clear_tsk_thread_flag(current, TIF_PER_TRAP); | |
436 | ||
aa33c8cb | 437 | trans_exc_code = regs->int_parm_long; |
61365e13 | 438 | if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) |
6252d702 MS |
439 | goto no_context; |
440 | ||
6252d702 | 441 | down_read(&mm->mmap_sem); |
50d7280d | 442 | vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK); |
6252d702 MS |
443 | up_read(&mm->mmap_sem); |
444 | ||
445 | if (vma) { | |
446 | update_mm(mm, current); | |
447 | return; | |
448 | } | |
449 | ||
450 | /* User mode accesses just cause a SIGSEGV */ | |
7d256175 | 451 | if (user_mode(regs)) { |
aa33c8cb | 452 | do_sigsegv(regs, SEGV_MAPERR); |
6252d702 MS |
453 | return; |
454 | } | |
455 | ||
456 | no_context: | |
aa33c8cb | 457 | do_no_context(regs); |
6252d702 MS |
458 | } |
459 | #endif | |
460 | ||
1e54622e | 461 | int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) |
6c1e3e79 GS |
462 | { |
463 | struct pt_regs regs; | |
464 | int access, fault; | |
465 | ||
008c2e8f | 466 | /* Emulate a uaccess fault from kernel mode. */ |
b50511e4 | 467 | regs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK; |
6c1e3e79 GS |
468 | if (!irqs_disabled()) |
469 | regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; | |
470 | regs.psw.addr = (unsigned long) __builtin_return_address(0); | |
471 | regs.psw.addr |= PSW_ADDR_AMODE; | |
aa33c8cb MS |
472 | regs.int_code = pgm_int_code; |
473 | regs.int_parm_long = (uaddr & PAGE_MASK) | 2; | |
1e54622e | 474 | access = write ? VM_WRITE : VM_READ; |
aa33c8cb | 475 | fault = do_exception(®s, access); |
008c2e8f HC |
476 | /* |
477 | * Since the fault happened in kernel mode while performing a uaccess | |
478 | * all we need to do now is emulating a fixup in case "fault" is not | |
479 | * zero. | |
480 | * For the calling uaccess functions this results always in -EFAULT. | |
481 | */ | |
6c1e3e79 GS |
482 | return fault ? -EFAULT : 0; |
483 | } | |
484 | ||
1da177e4 LT |
485 | #ifdef CONFIG_PFAULT |
486 | /* | |
487 | * 'pfault' pseudo page faults routines. | |
488 | */ | |
fb0a9d7e | 489 | static int pfault_disable; |
1da177e4 LT |
490 | |
491 | static int __init nopfault(char *str) | |
492 | { | |
493 | pfault_disable = 1; | |
494 | return 1; | |
495 | } | |
496 | ||
497 | __setup("nopfault", nopfault); | |
498 | ||
7dd8fe1f HC |
499 | struct pfault_refbk { |
500 | u16 refdiagc; | |
501 | u16 reffcode; | |
502 | u16 refdwlen; | |
503 | u16 refversn; | |
504 | u64 refgaddr; | |
505 | u64 refselmk; | |
506 | u64 refcmpmk; | |
507 | u64 reserved; | |
508 | } __attribute__ ((packed, aligned(8))); | |
1da177e4 LT |
509 | |
510 | int pfault_init(void) | |
511 | { | |
7dd8fe1f HC |
512 | struct pfault_refbk refbk = { |
513 | .refdiagc = 0x258, | |
514 | .reffcode = 0, | |
515 | .refdwlen = 5, | |
516 | .refversn = 2, | |
517 | .refgaddr = __LC_CURRENT_PID, | |
518 | .refselmk = 1ULL << 48, | |
519 | .refcmpmk = 1ULL << 48, | |
520 | .reserved = __PF_RES_FIELD }; | |
1da177e4 LT |
521 | int rc; |
522 | ||
f32269a0 | 523 | if (pfault_disable) |
1da177e4 | 524 | return -1; |
94c12cc7 MS |
525 | asm volatile( |
526 | " diag %1,%0,0x258\n" | |
527 | "0: j 2f\n" | |
528 | "1: la %0,8\n" | |
1da177e4 | 529 | "2:\n" |
94c12cc7 MS |
530 | EX_TABLE(0b,1b) |
531 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
532 | return rc; |
533 | } | |
534 | ||
535 | void pfault_fini(void) | |
536 | { | |
7dd8fe1f HC |
537 | struct pfault_refbk refbk = { |
538 | .refdiagc = 0x258, | |
539 | .reffcode = 1, | |
540 | .refdwlen = 5, | |
541 | .refversn = 2, | |
542 | }; | |
1da177e4 | 543 | |
f32269a0 | 544 | if (pfault_disable) |
1da177e4 | 545 | return; |
94c12cc7 MS |
546 | asm volatile( |
547 | " diag %0,0,0x258\n" | |
1da177e4 | 548 | "0:\n" |
94c12cc7 MS |
549 | EX_TABLE(0b,0b) |
550 | : : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
551 | } |
552 | ||
f2db2e6c HC |
553 | static DEFINE_SPINLOCK(pfault_lock); |
554 | static LIST_HEAD(pfault_list); | |
555 | ||
fde15c3a | 556 | static void pfault_interrupt(struct ext_code ext_code, |
f6649a7e | 557 | unsigned int param32, unsigned long param64) |
1da177e4 LT |
558 | { |
559 | struct task_struct *tsk; | |
560 | __u16 subcode; | |
f2db2e6c | 561 | pid_t pid; |
1da177e4 LT |
562 | |
563 | /* | |
564 | * Get the external interruption subcode & pfault | |
565 | * initial/completion signal bit. VM stores this | |
566 | * in the 'cpu address' field associated with the | |
567 | * external interrupt. | |
568 | */ | |
fde15c3a | 569 | subcode = ext_code.subcode; |
1da177e4 LT |
570 | if ((subcode & 0xff00) != __SUBCODE_MASK) |
571 | return; | |
420f42ec | 572 | inc_irq_stat(IRQEXT_PFL); |
54c27791 HC |
573 | /* Get the token (= pid of the affected task). */ |
574 | pid = sizeof(void *) == 4 ? param32 : param64; | |
575 | rcu_read_lock(); | |
576 | tsk = find_task_by_pid_ns(pid, &init_pid_ns); | |
577 | if (tsk) | |
578 | get_task_struct(tsk); | |
579 | rcu_read_unlock(); | |
580 | if (!tsk) | |
581 | return; | |
f2db2e6c | 582 | spin_lock(&pfault_lock); |
1da177e4 LT |
583 | if (subcode & 0x0080) { |
584 | /* signal bit is set -> a page has been swapped in by VM */ | |
f2db2e6c | 585 | if (tsk->thread.pfault_wait == 1) { |
1da177e4 LT |
586 | /* Initial interrupt was faster than the completion |
587 | * interrupt. pfault_wait is valid. Set pfault_wait | |
588 | * back to zero and wake up the process. This can | |
589 | * safely be done because the task is still sleeping | |
b6d09449 | 590 | * and can't produce new pfaults. */ |
1da177e4 | 591 | tsk->thread.pfault_wait = 0; |
f2db2e6c | 592 | list_del(&tsk->thread.list); |
1da177e4 | 593 | wake_up_process(tsk); |
d5e50a51 | 594 | put_task_struct(tsk); |
f2db2e6c HC |
595 | } else { |
596 | /* Completion interrupt was faster than initial | |
597 | * interrupt. Set pfault_wait to -1 so the initial | |
fa2fb2f4 HC |
598 | * interrupt doesn't put the task to sleep. |
599 | * If the task is not running, ignore the completion | |
600 | * interrupt since it must be a leftover of a PFAULT | |
601 | * CANCEL operation which didn't remove all pending | |
602 | * completion interrupts. */ | |
603 | if (tsk->state == TASK_RUNNING) | |
604 | tsk->thread.pfault_wait = -1; | |
1da177e4 LT |
605 | } |
606 | } else { | |
607 | /* signal bit not set -> a real page is missing. */ | |
d49f47f8 HC |
608 | if (WARN_ON_ONCE(tsk != current)) |
609 | goto out; | |
d5e50a51 HC |
610 | if (tsk->thread.pfault_wait == 1) { |
611 | /* Already on the list with a reference: put to sleep */ | |
0a16ba78 | 612 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
d5e50a51 HC |
613 | set_tsk_need_resched(tsk); |
614 | } else if (tsk->thread.pfault_wait == -1) { | |
1da177e4 | 615 | /* Completion interrupt was faster than the initial |
f2db2e6c HC |
616 | * interrupt (pfault_wait == -1). Set pfault_wait |
617 | * back to zero and exit. */ | |
1da177e4 | 618 | tsk->thread.pfault_wait = 0; |
f2db2e6c HC |
619 | } else { |
620 | /* Initial interrupt arrived before completion | |
d5e50a51 HC |
621 | * interrupt. Let the task sleep. |
622 | * An extra task reference is needed since a different | |
623 | * cpu may set the task state to TASK_RUNNING again | |
624 | * before the scheduler is reached. */ | |
625 | get_task_struct(tsk); | |
f2db2e6c HC |
626 | tsk->thread.pfault_wait = 1; |
627 | list_add(&tsk->thread.list, &pfault_list); | |
0a16ba78 | 628 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
1da177e4 | 629 | set_tsk_need_resched(tsk); |
f2db2e6c HC |
630 | } |
631 | } | |
d49f47f8 | 632 | out: |
f2db2e6c | 633 | spin_unlock(&pfault_lock); |
54c27791 | 634 | put_task_struct(tsk); |
f2db2e6c HC |
635 | } |
636 | ||
637 | static int __cpuinit pfault_cpu_notify(struct notifier_block *self, | |
638 | unsigned long action, void *hcpu) | |
639 | { | |
640 | struct thread_struct *thread, *next; | |
641 | struct task_struct *tsk; | |
642 | ||
1c725922 | 643 | switch (action & ~CPU_TASKS_FROZEN) { |
f2db2e6c | 644 | case CPU_DEAD: |
f2db2e6c HC |
645 | spin_lock_irq(&pfault_lock); |
646 | list_for_each_entry_safe(thread, next, &pfault_list, list) { | |
647 | thread->pfault_wait = 0; | |
648 | list_del(&thread->list); | |
649 | tsk = container_of(thread, struct task_struct, thread); | |
650 | wake_up_process(tsk); | |
d5e50a51 | 651 | put_task_struct(tsk); |
f2db2e6c HC |
652 | } |
653 | spin_unlock_irq(&pfault_lock); | |
654 | break; | |
655 | default: | |
656 | break; | |
1da177e4 | 657 | } |
f2db2e6c | 658 | return NOTIFY_OK; |
1da177e4 | 659 | } |
1da177e4 | 660 | |
fb0a9d7e | 661 | static int __init pfault_irq_init(void) |
29b08d2b | 662 | { |
fb0a9d7e | 663 | int rc; |
29b08d2b | 664 | |
fb0a9d7e | 665 | rc = register_external_interrupt(0x2603, pfault_interrupt); |
7dd8fe1f HC |
666 | if (rc) |
667 | goto out_extint; | |
668 | rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; | |
669 | if (rc) | |
670 | goto out_pfault; | |
df7997ab | 671 | service_subclass_irq_register(); |
7dd8fe1f HC |
672 | hotcpu_notifier(pfault_cpu_notify, 0); |
673 | return 0; | |
29b08d2b | 674 | |
7dd8fe1f | 675 | out_pfault: |
fb0a9d7e | 676 | unregister_external_interrupt(0x2603, pfault_interrupt); |
7dd8fe1f HC |
677 | out_extint: |
678 | pfault_disable = 1; | |
679 | return rc; | |
29b08d2b | 680 | } |
fb0a9d7e HC |
681 | early_initcall(pfault_irq_init); |
682 | ||
7dd8fe1f | 683 | #endif /* CONFIG_PFAULT */ |