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Commit | Line | Data |
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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 | |
1da177e4 | 39 | #define __FAIL_ADDR_MASK -4096L |
1da177e4 LT |
40 | #define __SUBCODE_MASK 0x0600 |
41 | #define __PF_RES_FIELD 0x8000000000000000ULL | |
1da177e4 | 42 | |
50d7280d MS |
43 | #define VM_FAULT_BADCONTEXT 0x010000 |
44 | #define VM_FAULT_BADMAP 0x020000 | |
45 | #define VM_FAULT_BADACCESS 0x040000 | |
a4f32bdb | 46 | #define VM_FAULT_SIGNAL 0x080000 |
24eb3a82 | 47 | #define VM_FAULT_PFAULT 0x100000 |
50d7280d | 48 | |
a4f32bdb | 49 | static unsigned long store_indication __read_mostly; |
92f842ea | 50 | |
a4f32bdb | 51 | static int __init fault_init(void) |
92f842ea | 52 | { |
a4f32bdb | 53 | if (test_facility(75)) |
92f842ea | 54 | store_indication = 0xc00; |
a4f32bdb | 55 | return 0; |
92f842ea | 56 | } |
a4f32bdb | 57 | early_initcall(fault_init); |
92f842ea | 58 | |
7ecb344a | 59 | static inline int notify_page_fault(struct pt_regs *regs) |
10c1031f | 60 | { |
33464e3b CH |
61 | int ret = 0; |
62 | ||
63 | /* kprobe_running() needs smp_processor_id() */ | |
22e0a046 | 64 | if (kprobes_built_in() && !user_mode(regs)) { |
33464e3b CH |
65 | preempt_disable(); |
66 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
67 | ret = 1; | |
68 | preempt_enable(); | |
69 | } | |
33464e3b | 70 | return ret; |
4ba069b8 | 71 | } |
4ba069b8 | 72 | |
1da177e4 LT |
73 | |
74 | /* | |
75 | * Unlock any spinlocks which will prevent us from getting the | |
cefc8be8 | 76 | * message out. |
1da177e4 LT |
77 | */ |
78 | void bust_spinlocks(int yes) | |
79 | { | |
80 | if (yes) { | |
81 | oops_in_progress = 1; | |
82 | } else { | |
83 | int loglevel_save = console_loglevel; | |
84 | console_unblank(); | |
85 | oops_in_progress = 0; | |
86 | /* | |
87 | * OK, the message is on the console. Now we call printk() | |
88 | * without oops_in_progress set so that printk will give klogd | |
89 | * a poke. Hold onto your hats... | |
90 | */ | |
91 | console_loglevel = 15; | |
92 | printk(" "); | |
93 | console_loglevel = loglevel_save; | |
94 | } | |
95 | } | |
96 | ||
97 | /* | |
482b05dd | 98 | * Returns the address space associated with the fault. |
61365e13 | 99 | * Returns 0 for kernel space and 1 for user space. |
1da177e4 | 100 | */ |
457f2180 | 101 | static inline int user_space_fault(struct pt_regs *regs) |
1da177e4 | 102 | { |
457f2180 HC |
103 | unsigned long trans_exc_code; |
104 | ||
1da177e4 | 105 | /* |
61365e13 MS |
106 | * The lowest two bits of the translation exception |
107 | * identification indicate which paging table was used. | |
1da177e4 | 108 | */ |
457f2180 HC |
109 | trans_exc_code = regs->int_parm_long & 3; |
110 | if (trans_exc_code == 3) /* home space -> kernel */ | |
111 | return 0; | |
112 | if (user_mode(regs)) | |
113 | return 1; | |
114 | if (trans_exc_code == 2) /* secondary space -> set_fs */ | |
61365e13 | 115 | return current->thread.mm_segment.ar4; |
457f2180 HC |
116 | if (current->flags & PF_VCPU) |
117 | return 1; | |
118 | return 0; | |
1da177e4 LT |
119 | } |
120 | ||
3b7df342 HC |
121 | static int bad_address(void *p) |
122 | { | |
123 | unsigned long dummy; | |
124 | ||
125 | return probe_kernel_address((unsigned long *)p, dummy); | |
126 | } | |
127 | ||
3b7df342 HC |
128 | static void dump_pagetable(unsigned long asce, unsigned long address) |
129 | { | |
130 | unsigned long *table = __va(asce & PAGE_MASK); | |
131 | ||
132 | pr_alert("AS:%016lx ", asce); | |
133 | switch (asce & _ASCE_TYPE_MASK) { | |
134 | case _ASCE_TYPE_REGION1: | |
135 | table = table + ((address >> 53) & 0x7ff); | |
136 | if (bad_address(table)) | |
137 | goto bad; | |
138 | pr_cont("R1:%016lx ", *table); | |
139 | if (*table & _REGION_ENTRY_INVALID) | |
140 | goto out; | |
141 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); | |
142 | /* fallthrough */ | |
143 | case _ASCE_TYPE_REGION2: | |
144 | table = table + ((address >> 42) & 0x7ff); | |
145 | if (bad_address(table)) | |
146 | goto bad; | |
147 | pr_cont("R2:%016lx ", *table); | |
148 | if (*table & _REGION_ENTRY_INVALID) | |
149 | goto out; | |
150 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); | |
151 | /* fallthrough */ | |
152 | case _ASCE_TYPE_REGION3: | |
153 | table = table + ((address >> 31) & 0x7ff); | |
154 | if (bad_address(table)) | |
155 | goto bad; | |
156 | pr_cont("R3:%016lx ", *table); | |
157 | if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) | |
158 | goto out; | |
159 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); | |
160 | /* fallthrough */ | |
161 | case _ASCE_TYPE_SEGMENT: | |
162 | table = table + ((address >> 20) & 0x7ff); | |
163 | if (bad_address(table)) | |
164 | goto bad; | |
91c0837e | 165 | pr_cont("S:%016lx ", *table); |
3b7df342 HC |
166 | if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) |
167 | goto out; | |
168 | table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); | |
169 | } | |
170 | table = table + ((address >> 12) & 0xff); | |
171 | if (bad_address(table)) | |
172 | goto bad; | |
173 | pr_cont("P:%016lx ", *table); | |
174 | out: | |
175 | pr_cont("\n"); | |
176 | return; | |
177 | bad: | |
178 | pr_cont("BAD\n"); | |
179 | } | |
180 | ||
3b7df342 HC |
181 | static void dump_fault_info(struct pt_regs *regs) |
182 | { | |
183 | unsigned long asce; | |
184 | ||
185 | pr_alert("Fault in "); | |
186 | switch (regs->int_parm_long & 3) { | |
187 | case 3: | |
188 | pr_cont("home space "); | |
189 | break; | |
190 | case 2: | |
191 | pr_cont("secondary space "); | |
192 | break; | |
193 | case 1: | |
194 | pr_cont("access register "); | |
195 | break; | |
196 | case 0: | |
197 | pr_cont("primary space "); | |
198 | break; | |
199 | } | |
200 | pr_cont("mode while using "); | |
201 | if (!user_space_fault(regs)) { | |
202 | asce = S390_lowcore.kernel_asce; | |
203 | pr_cont("kernel "); | |
204 | } | |
205 | #ifdef CONFIG_PGSTE | |
206 | else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { | |
207 | struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; | |
208 | asce = gmap->asce; | |
209 | pr_cont("gmap "); | |
210 | } | |
211 | #endif | |
212 | else { | |
213 | asce = S390_lowcore.user_asce; | |
214 | pr_cont("user "); | |
215 | } | |
216 | pr_cont("ASCE.\n"); | |
217 | dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); | |
218 | } | |
219 | ||
aa33c8cb | 220 | static inline void report_user_fault(struct pt_regs *regs, long signr) |
ab3c68ee HC |
221 | { |
222 | if ((task_pid_nr(current) > 1) && !show_unhandled_signals) | |
223 | return; | |
224 | if (!unhandled_signal(current, signr)) | |
225 | return; | |
226 | if (!printk_ratelimit()) | |
227 | return; | |
db1177ee | 228 | printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ", |
413d4047 | 229 | regs->int_code & 0xffff, regs->int_code >> 17); |
ab3c68ee | 230 | print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); |
aa33c8cb | 231 | printk(KERN_CONT "\n"); |
3b7df342 HC |
232 | printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", |
233 | regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); | |
234 | dump_fault_info(regs); | |
ab3c68ee HC |
235 | show_regs(regs); |
236 | } | |
237 | ||
1da177e4 LT |
238 | /* |
239 | * Send SIGSEGV to task. This is an external routine | |
240 | * to keep the stack usage of do_page_fault small. | |
241 | */ | |
aa33c8cb | 242 | static noinline void do_sigsegv(struct pt_regs *regs, int si_code) |
1da177e4 LT |
243 | { |
244 | struct siginfo si; | |
245 | ||
aa33c8cb | 246 | report_user_fault(regs, SIGSEGV); |
1da177e4 LT |
247 | si.si_signo = SIGSEGV; |
248 | si.si_code = si_code; | |
aa33c8cb | 249 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
1da177e4 LT |
250 | force_sig_info(SIGSEGV, &si, current); |
251 | } | |
252 | ||
aa33c8cb | 253 | static noinline void do_no_context(struct pt_regs *regs) |
10c1031f MS |
254 | { |
255 | const struct exception_table_entry *fixup; | |
61365e13 | 256 | unsigned long address; |
10c1031f MS |
257 | |
258 | /* Are we prepared to handle this kernel fault? */ | |
50d7280d | 259 | fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); |
10c1031f | 260 | if (fixup) { |
eb608fb3 | 261 | regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; |
10c1031f MS |
262 | return; |
263 | } | |
264 | ||
265 | /* | |
266 | * Oops. The kernel tried to access some bad page. We'll have to | |
267 | * terminate things with extreme prejudice. | |
268 | */ | |
aa33c8cb | 269 | address = regs->int_parm_long & __FAIL_ADDR_MASK; |
457f2180 | 270 | if (!user_space_fault(regs)) |
10c1031f | 271 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" |
3b7df342 | 272 | " in virtual kernel address space\n"); |
10c1031f MS |
273 | else |
274 | printk(KERN_ALERT "Unable to handle kernel paging request" | |
3b7df342 HC |
275 | " in virtual user address space\n"); |
276 | printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", | |
277 | regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); | |
278 | dump_fault_info(regs); | |
aa33c8cb | 279 | die(regs, "Oops"); |
10c1031f MS |
280 | do_exit(SIGKILL); |
281 | } | |
282 | ||
aa33c8cb | 283 | static noinline void do_low_address(struct pt_regs *regs) |
10c1031f MS |
284 | { |
285 | /* Low-address protection hit in kernel mode means | |
286 | NULL pointer write access in kernel mode. */ | |
287 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
288 | /* Low-address protection hit in user mode 'cannot happen'. */ | |
aa33c8cb | 289 | die (regs, "Low-address protection"); |
10c1031f MS |
290 | do_exit(SIGKILL); |
291 | } | |
292 | ||
aa33c8cb | 293 | do_no_context(regs); |
10c1031f MS |
294 | } |
295 | ||
aa33c8cb | 296 | static noinline void do_sigbus(struct pt_regs *regs) |
10c1031f MS |
297 | { |
298 | struct task_struct *tsk = current; | |
36bf9680 | 299 | struct siginfo si; |
10c1031f | 300 | |
10c1031f MS |
301 | /* |
302 | * Send a sigbus, regardless of whether we were in kernel | |
303 | * or user mode. | |
304 | */ | |
36bf9680 MS |
305 | si.si_signo = SIGBUS; |
306 | si.si_errno = 0; | |
307 | si.si_code = BUS_ADRERR; | |
aa33c8cb | 308 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
36bf9680 | 309 | force_sig_info(SIGBUS, &si, tsk); |
10c1031f MS |
310 | } |
311 | ||
aa33c8cb | 312 | static noinline void do_fault_error(struct pt_regs *regs, int fault) |
50d7280d MS |
313 | { |
314 | int si_code; | |
315 | ||
316 | switch (fault) { | |
317 | case VM_FAULT_BADACCESS: | |
50d7280d MS |
318 | case VM_FAULT_BADMAP: |
319 | /* Bad memory access. Check if it is kernel or user space. */ | |
7d256175 | 320 | if (user_mode(regs)) { |
50d7280d MS |
321 | /* User mode accesses just cause a SIGSEGV */ |
322 | si_code = (fault == VM_FAULT_BADMAP) ? | |
323 | SEGV_MAPERR : SEGV_ACCERR; | |
aa33c8cb | 324 | do_sigsegv(regs, si_code); |
50d7280d MS |
325 | return; |
326 | } | |
327 | case VM_FAULT_BADCONTEXT: | |
24eb3a82 | 328 | case VM_FAULT_PFAULT: |
aa33c8cb | 329 | do_no_context(regs); |
50d7280d | 330 | break; |
f2c76e3b HC |
331 | case VM_FAULT_SIGNAL: |
332 | if (!user_mode(regs)) | |
333 | do_no_context(regs); | |
334 | break; | |
50d7280d | 335 | default: /* fault & VM_FAULT_ERROR */ |
99583181 | 336 | if (fault & VM_FAULT_OOM) { |
7d256175 | 337 | if (!user_mode(regs)) |
aa33c8cb | 338 | do_no_context(regs); |
99583181 HC |
339 | else |
340 | pagefault_out_of_memory(); | |
33692f27 LT |
341 | } else if (fault & VM_FAULT_SIGSEGV) { |
342 | /* Kernel mode? Handle exceptions or die */ | |
343 | if (!user_mode(regs)) | |
344 | do_no_context(regs); | |
345 | else | |
346 | do_sigsegv(regs, SEGV_MAPERR); | |
99583181 | 347 | } else if (fault & VM_FAULT_SIGBUS) { |
50d7280d | 348 | /* Kernel mode? Handle exceptions or die */ |
7d256175 | 349 | if (!user_mode(regs)) |
aa33c8cb | 350 | do_no_context(regs); |
36bf9680 | 351 | else |
aa33c8cb | 352 | do_sigbus(regs); |
50d7280d MS |
353 | } else |
354 | BUG(); | |
355 | break; | |
356 | } | |
357 | } | |
358 | ||
1da177e4 LT |
359 | /* |
360 | * This routine handles page faults. It determines the address, | |
361 | * and the problem, and then passes it off to one of the appropriate | |
362 | * routines. | |
363 | * | |
50d7280d | 364 | * interruption code (int_code): |
1da177e4 LT |
365 | * 04 Protection -> Write-Protection (suprression) |
366 | * 10 Segment translation -> Not present (nullification) | |
367 | * 11 Page translation -> Not present (nullification) | |
368 | * 3b Region third trans. -> Not present (nullification) | |
369 | */ | |
aa33c8cb | 370 | static inline int do_exception(struct pt_regs *regs, int access) |
1da177e4 | 371 | { |
24eb3a82 DD |
372 | #ifdef CONFIG_PGSTE |
373 | struct gmap *gmap; | |
374 | #endif | |
10c1031f MS |
375 | struct task_struct *tsk; |
376 | struct mm_struct *mm; | |
377 | struct vm_area_struct *vma; | |
aa33c8cb | 378 | unsigned long trans_exc_code; |
10c1031f | 379 | unsigned long address; |
33ce6140 HC |
380 | unsigned int flags; |
381 | int fault; | |
1da177e4 | 382 | |
39efd4ec MS |
383 | tsk = current; |
384 | /* | |
385 | * The instruction that caused the program check has | |
386 | * been nullified. Don't signal single step via SIGTRAP. | |
387 | */ | |
d3a73acb | 388 | clear_pt_regs_flag(regs, PIF_PER_TRAP); |
39efd4ec | 389 | |
7ecb344a | 390 | if (notify_page_fault(regs)) |
50d7280d | 391 | return 0; |
4ba069b8 | 392 | |
10c1031f | 393 | mm = tsk->mm; |
aa33c8cb | 394 | trans_exc_code = regs->int_parm_long; |
1da177e4 | 395 | |
1da177e4 LT |
396 | /* |
397 | * Verify that the fault happened in user space, that | |
398 | * we are not in an interrupt and that there is a | |
399 | * user context. | |
400 | */ | |
50d7280d | 401 | fault = VM_FAULT_BADCONTEXT; |
457f2180 | 402 | if (unlikely(!user_space_fault(regs) || in_atomic() || !mm)) |
50d7280d | 403 | goto out; |
1da177e4 | 404 | |
61365e13 | 405 | address = trans_exc_code & __FAIL_ADDR_MASK; |
a8b0ca17 | 406 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
f2c76e3b | 407 | flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
759496ba JW |
408 | if (user_mode(regs)) |
409 | flags |= FAULT_FLAG_USER; | |
33ce6140 HC |
410 | if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) |
411 | flags |= FAULT_FLAG_WRITE; | |
10c1031f | 412 | down_read(&mm->mmap_sem); |
1da177e4 | 413 | |
e5992f2e | 414 | #ifdef CONFIG_PGSTE |
527e30b4 MS |
415 | gmap = (current->flags & PF_VCPU) ? |
416 | (struct gmap *) S390_lowcore.gmap : NULL; | |
24eb3a82 | 417 | if (gmap) { |
527e30b4 MS |
418 | current->thread.gmap_addr = address; |
419 | address = __gmap_translate(gmap, address); | |
e5992f2e MS |
420 | if (address == -EFAULT) { |
421 | fault = VM_FAULT_BADMAP; | |
422 | goto out_up; | |
423 | } | |
24eb3a82 DD |
424 | if (gmap->pfault_enabled) |
425 | flags |= FAULT_FLAG_RETRY_NOWAIT; | |
e5992f2e MS |
426 | } |
427 | #endif | |
428 | ||
429 | retry: | |
50d7280d | 430 | fault = VM_FAULT_BADMAP; |
482b05dd GS |
431 | vma = find_vma(mm, address); |
432 | if (!vma) | |
50d7280d | 433 | goto out_up; |
c1821c2e | 434 | |
50d7280d MS |
435 | if (unlikely(vma->vm_start > address)) { |
436 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
437 | goto out_up; | |
438 | if (expand_stack(vma, address)) | |
439 | goto out_up; | |
440 | } | |
441 | ||
442 | /* | |
443 | * Ok, we have a good vm_area for this memory access, so | |
444 | * we can handle it.. | |
445 | */ | |
446 | fault = VM_FAULT_BADACCESS; | |
1ab947de | 447 | if (unlikely(!(vma->vm_flags & access))) |
50d7280d | 448 | goto out_up; |
1da177e4 | 449 | |
53492b1d GS |
450 | if (is_vm_hugetlb_page(vma)) |
451 | address &= HPAGE_MASK; | |
1da177e4 LT |
452 | /* |
453 | * If for any reason at all we couldn't handle the fault, | |
454 | * make sure we exit gracefully rather than endlessly redo | |
455 | * the fault. | |
456 | */ | |
33ce6140 | 457 | fault = handle_mm_fault(mm, vma, address, flags); |
f2c76e3b HC |
458 | /* No reason to continue if interrupted by SIGKILL. */ |
459 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { | |
460 | fault = VM_FAULT_SIGNAL; | |
461 | goto out; | |
462 | } | |
50d7280d MS |
463 | if (unlikely(fault & VM_FAULT_ERROR)) |
464 | goto out_up; | |
465 | ||
33ce6140 HC |
466 | /* |
467 | * Major/minor page fault accounting is only done on the | |
468 | * initial attempt. If we go through a retry, it is extremely | |
469 | * likely that the page will be found in page cache at that point. | |
470 | */ | |
471 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
472 | if (fault & VM_FAULT_MAJOR) { | |
473 | tsk->maj_flt++; | |
a8b0ca17 | 474 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, |
33ce6140 HC |
475 | regs, address); |
476 | } else { | |
477 | tsk->min_flt++; | |
a8b0ca17 | 478 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, |
33ce6140 HC |
479 | regs, address); |
480 | } | |
481 | if (fault & VM_FAULT_RETRY) { | |
24eb3a82 DD |
482 | #ifdef CONFIG_PGSTE |
483 | if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { | |
484 | /* FAULT_FLAG_RETRY_NOWAIT has been set, | |
485 | * mmap_sem has not been released */ | |
486 | current->thread.gmap_pfault = 1; | |
487 | fault = VM_FAULT_PFAULT; | |
488 | goto out_up; | |
489 | } | |
490 | #endif | |
33ce6140 HC |
491 | /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk |
492 | * of starvation. */ | |
24eb3a82 DD |
493 | flags &= ~(FAULT_FLAG_ALLOW_RETRY | |
494 | FAULT_FLAG_RETRY_NOWAIT); | |
45cac65b | 495 | flags |= FAULT_FLAG_TRIED; |
e5992f2e | 496 | down_read(&mm->mmap_sem); |
33ce6140 HC |
497 | goto retry; |
498 | } | |
bde69af2 | 499 | } |
527e30b4 MS |
500 | #ifdef CONFIG_PGSTE |
501 | if (gmap) { | |
502 | address = __gmap_link(gmap, current->thread.gmap_addr, | |
503 | address); | |
504 | if (address == -EFAULT) { | |
505 | fault = VM_FAULT_BADMAP; | |
506 | goto out_up; | |
507 | } | |
508 | if (address == -ENOMEM) { | |
509 | fault = VM_FAULT_OOM; | |
510 | goto out_up; | |
511 | } | |
512 | } | |
513 | #endif | |
50d7280d MS |
514 | fault = 0; |
515 | out_up: | |
10c1031f | 516 | up_read(&mm->mmap_sem); |
50d7280d MS |
517 | out: |
518 | return fault; | |
1da177e4 LT |
519 | } |
520 | ||
7a5388de | 521 | void do_protection_exception(struct pt_regs *regs) |
1da177e4 | 522 | { |
aa33c8cb | 523 | unsigned long trans_exc_code; |
50d7280d | 524 | int fault; |
61365e13 | 525 | |
aa33c8cb | 526 | trans_exc_code = regs->int_parm_long; |
f752ac4d MS |
527 | /* |
528 | * Protection exceptions are suppressing, decrement psw address. | |
529 | * The exception to this rule are aborted transactions, for these | |
530 | * the PSW already points to the correct location. | |
531 | */ | |
532 | if (!(regs->int_code & 0x200)) | |
533 | regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); | |
10c1031f MS |
534 | /* |
535 | * Check for low-address protection. This needs to be treated | |
536 | * as a special case because the translation exception code | |
537 | * field is not guaranteed to contain valid data in this case. | |
538 | */ | |
61365e13 | 539 | if (unlikely(!(trans_exc_code & 4))) { |
aa33c8cb | 540 | do_low_address(regs); |
10c1031f MS |
541 | return; |
542 | } | |
aa33c8cb | 543 | fault = do_exception(regs, VM_WRITE); |
50d7280d | 544 | if (unlikely(fault)) |
aa33c8cb | 545 | do_fault_error(regs, fault); |
1da177e4 | 546 | } |
7a5388de | 547 | NOKPROBE_SYMBOL(do_protection_exception); |
1da177e4 | 548 | |
7a5388de | 549 | void do_dat_exception(struct pt_regs *regs) |
1da177e4 | 550 | { |
1ab947de | 551 | int access, fault; |
50d7280d | 552 | |
1ab947de | 553 | access = VM_READ | VM_EXEC | VM_WRITE; |
aa33c8cb | 554 | fault = do_exception(regs, access); |
50d7280d | 555 | if (unlikely(fault)) |
aa33c8cb | 556 | do_fault_error(regs, fault); |
1da177e4 | 557 | } |
7a5388de | 558 | NOKPROBE_SYMBOL(do_dat_exception); |
1da177e4 | 559 | |
1da177e4 LT |
560 | #ifdef CONFIG_PFAULT |
561 | /* | |
562 | * 'pfault' pseudo page faults routines. | |
563 | */ | |
fb0a9d7e | 564 | static int pfault_disable; |
1da177e4 LT |
565 | |
566 | static int __init nopfault(char *str) | |
567 | { | |
568 | pfault_disable = 1; | |
569 | return 1; | |
570 | } | |
571 | ||
572 | __setup("nopfault", nopfault); | |
573 | ||
7dd8fe1f HC |
574 | struct pfault_refbk { |
575 | u16 refdiagc; | |
576 | u16 reffcode; | |
577 | u16 refdwlen; | |
578 | u16 refversn; | |
579 | u64 refgaddr; | |
580 | u64 refselmk; | |
581 | u64 refcmpmk; | |
582 | u64 reserved; | |
583 | } __attribute__ ((packed, aligned(8))); | |
1da177e4 LT |
584 | |
585 | int pfault_init(void) | |
586 | { | |
7dd8fe1f HC |
587 | struct pfault_refbk refbk = { |
588 | .refdiagc = 0x258, | |
589 | .reffcode = 0, | |
590 | .refdwlen = 5, | |
591 | .refversn = 2, | |
592 | .refgaddr = __LC_CURRENT_PID, | |
593 | .refselmk = 1ULL << 48, | |
594 | .refcmpmk = 1ULL << 48, | |
595 | .reserved = __PF_RES_FIELD }; | |
1da177e4 LT |
596 | int rc; |
597 | ||
f32269a0 | 598 | if (pfault_disable) |
1da177e4 | 599 | return -1; |
94c12cc7 MS |
600 | asm volatile( |
601 | " diag %1,%0,0x258\n" | |
602 | "0: j 2f\n" | |
603 | "1: la %0,8\n" | |
1da177e4 | 604 | "2:\n" |
94c12cc7 MS |
605 | EX_TABLE(0b,1b) |
606 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
607 | return rc; |
608 | } | |
609 | ||
610 | void pfault_fini(void) | |
611 | { | |
7dd8fe1f HC |
612 | struct pfault_refbk refbk = { |
613 | .refdiagc = 0x258, | |
614 | .reffcode = 1, | |
615 | .refdwlen = 5, | |
616 | .refversn = 2, | |
617 | }; | |
1da177e4 | 618 | |
f32269a0 | 619 | if (pfault_disable) |
1da177e4 | 620 | return; |
94c12cc7 MS |
621 | asm volatile( |
622 | " diag %0,0,0x258\n" | |
1da177e4 | 623 | "0:\n" |
94c12cc7 MS |
624 | EX_TABLE(0b,0b) |
625 | : : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
626 | } |
627 | ||
f2db2e6c HC |
628 | static DEFINE_SPINLOCK(pfault_lock); |
629 | static LIST_HEAD(pfault_list); | |
630 | ||
fde15c3a | 631 | static void pfault_interrupt(struct ext_code ext_code, |
f6649a7e | 632 | unsigned int param32, unsigned long param64) |
1da177e4 LT |
633 | { |
634 | struct task_struct *tsk; | |
635 | __u16 subcode; | |
f2db2e6c | 636 | pid_t pid; |
1da177e4 LT |
637 | |
638 | /* | |
639 | * Get the external interruption subcode & pfault | |
640 | * initial/completion signal bit. VM stores this | |
641 | * in the 'cpu address' field associated with the | |
642 | * external interrupt. | |
643 | */ | |
fde15c3a | 644 | subcode = ext_code.subcode; |
1da177e4 LT |
645 | if ((subcode & 0xff00) != __SUBCODE_MASK) |
646 | return; | |
420f42ec | 647 | inc_irq_stat(IRQEXT_PFL); |
54c27791 HC |
648 | /* Get the token (= pid of the affected task). */ |
649 | pid = sizeof(void *) == 4 ? param32 : param64; | |
650 | rcu_read_lock(); | |
651 | tsk = find_task_by_pid_ns(pid, &init_pid_ns); | |
652 | if (tsk) | |
653 | get_task_struct(tsk); | |
654 | rcu_read_unlock(); | |
655 | if (!tsk) | |
656 | return; | |
f2db2e6c | 657 | spin_lock(&pfault_lock); |
1da177e4 LT |
658 | if (subcode & 0x0080) { |
659 | /* signal bit is set -> a page has been swapped in by VM */ | |
f2db2e6c | 660 | if (tsk->thread.pfault_wait == 1) { |
1da177e4 LT |
661 | /* Initial interrupt was faster than the completion |
662 | * interrupt. pfault_wait is valid. Set pfault_wait | |
663 | * back to zero and wake up the process. This can | |
664 | * safely be done because the task is still sleeping | |
b6d09449 | 665 | * and can't produce new pfaults. */ |
1da177e4 | 666 | tsk->thread.pfault_wait = 0; |
f2db2e6c | 667 | list_del(&tsk->thread.list); |
1da177e4 | 668 | wake_up_process(tsk); |
d5e50a51 | 669 | put_task_struct(tsk); |
f2db2e6c HC |
670 | } else { |
671 | /* Completion interrupt was faster than initial | |
672 | * interrupt. Set pfault_wait to -1 so the initial | |
fa2fb2f4 HC |
673 | * interrupt doesn't put the task to sleep. |
674 | * If the task is not running, ignore the completion | |
675 | * interrupt since it must be a leftover of a PFAULT | |
676 | * CANCEL operation which didn't remove all pending | |
677 | * completion interrupts. */ | |
678 | if (tsk->state == TASK_RUNNING) | |
679 | tsk->thread.pfault_wait = -1; | |
1da177e4 LT |
680 | } |
681 | } else { | |
682 | /* signal bit not set -> a real page is missing. */ | |
d49f47f8 HC |
683 | if (WARN_ON_ONCE(tsk != current)) |
684 | goto out; | |
d5e50a51 HC |
685 | if (tsk->thread.pfault_wait == 1) { |
686 | /* Already on the list with a reference: put to sleep */ | |
0a16ba78 | 687 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
d5e50a51 HC |
688 | set_tsk_need_resched(tsk); |
689 | } else if (tsk->thread.pfault_wait == -1) { | |
1da177e4 | 690 | /* Completion interrupt was faster than the initial |
f2db2e6c HC |
691 | * interrupt (pfault_wait == -1). Set pfault_wait |
692 | * back to zero and exit. */ | |
1da177e4 | 693 | tsk->thread.pfault_wait = 0; |
f2db2e6c HC |
694 | } else { |
695 | /* Initial interrupt arrived before completion | |
d5e50a51 HC |
696 | * interrupt. Let the task sleep. |
697 | * An extra task reference is needed since a different | |
698 | * cpu may set the task state to TASK_RUNNING again | |
699 | * before the scheduler is reached. */ | |
700 | get_task_struct(tsk); | |
f2db2e6c HC |
701 | tsk->thread.pfault_wait = 1; |
702 | list_add(&tsk->thread.list, &pfault_list); | |
0a16ba78 | 703 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
1da177e4 | 704 | set_tsk_need_resched(tsk); |
f2db2e6c HC |
705 | } |
706 | } | |
d49f47f8 | 707 | out: |
f2db2e6c | 708 | spin_unlock(&pfault_lock); |
54c27791 | 709 | put_task_struct(tsk); |
f2db2e6c HC |
710 | } |
711 | ||
e2741f17 PG |
712 | static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, |
713 | void *hcpu) | |
f2db2e6c HC |
714 | { |
715 | struct thread_struct *thread, *next; | |
716 | struct task_struct *tsk; | |
717 | ||
1c725922 | 718 | switch (action & ~CPU_TASKS_FROZEN) { |
f2db2e6c | 719 | case CPU_DEAD: |
f2db2e6c HC |
720 | spin_lock_irq(&pfault_lock); |
721 | list_for_each_entry_safe(thread, next, &pfault_list, list) { | |
722 | thread->pfault_wait = 0; | |
723 | list_del(&thread->list); | |
724 | tsk = container_of(thread, struct task_struct, thread); | |
725 | wake_up_process(tsk); | |
d5e50a51 | 726 | put_task_struct(tsk); |
f2db2e6c HC |
727 | } |
728 | spin_unlock_irq(&pfault_lock); | |
729 | break; | |
730 | default: | |
731 | break; | |
1da177e4 | 732 | } |
f2db2e6c | 733 | return NOTIFY_OK; |
1da177e4 | 734 | } |
1da177e4 | 735 | |
fb0a9d7e | 736 | static int __init pfault_irq_init(void) |
29b08d2b | 737 | { |
fb0a9d7e | 738 | int rc; |
29b08d2b | 739 | |
1dad093b | 740 | rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); |
7dd8fe1f HC |
741 | if (rc) |
742 | goto out_extint; | |
743 | rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; | |
744 | if (rc) | |
745 | goto out_pfault; | |
82003c3e | 746 | irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); |
7dd8fe1f HC |
747 | hotcpu_notifier(pfault_cpu_notify, 0); |
748 | return 0; | |
29b08d2b | 749 | |
7dd8fe1f | 750 | out_pfault: |
1dad093b | 751 | unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); |
7dd8fe1f HC |
752 | out_extint: |
753 | pfault_disable = 1; | |
754 | return rc; | |
29b08d2b | 755 | } |
fb0a9d7e HC |
756 | early_initcall(pfault_irq_init); |
757 | ||
7dd8fe1f | 758 | #endif /* CONFIG_PFAULT */ |