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 |
24eb3a82 | 53 | #define VM_FAULT_PFAULT 0x100000 |
50d7280d | 54 | |
a4f32bdb | 55 | static unsigned long store_indication __read_mostly; |
92f842ea | 56 | |
a4f32bdb HC |
57 | #ifdef CONFIG_64BIT |
58 | static int __init fault_init(void) | |
92f842ea | 59 | { |
a4f32bdb | 60 | if (test_facility(75)) |
92f842ea | 61 | store_indication = 0xc00; |
a4f32bdb | 62 | return 0; |
92f842ea | 63 | } |
a4f32bdb HC |
64 | early_initcall(fault_init); |
65 | #endif | |
92f842ea | 66 | |
7ecb344a | 67 | static inline int notify_page_fault(struct pt_regs *regs) |
10c1031f | 68 | { |
33464e3b CH |
69 | int ret = 0; |
70 | ||
71 | /* kprobe_running() needs smp_processor_id() */ | |
22e0a046 | 72 | if (kprobes_built_in() && !user_mode(regs)) { |
33464e3b CH |
73 | preempt_disable(); |
74 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
75 | ret = 1; | |
76 | preempt_enable(); | |
77 | } | |
33464e3b | 78 | return ret; |
4ba069b8 | 79 | } |
4ba069b8 | 80 | |
1da177e4 LT |
81 | |
82 | /* | |
83 | * Unlock any spinlocks which will prevent us from getting the | |
cefc8be8 | 84 | * message out. |
1da177e4 LT |
85 | */ |
86 | void bust_spinlocks(int yes) | |
87 | { | |
88 | if (yes) { | |
89 | oops_in_progress = 1; | |
90 | } else { | |
91 | int loglevel_save = console_loglevel; | |
92 | console_unblank(); | |
93 | oops_in_progress = 0; | |
94 | /* | |
95 | * OK, the message is on the console. Now we call printk() | |
96 | * without oops_in_progress set so that printk will give klogd | |
97 | * a poke. Hold onto your hats... | |
98 | */ | |
99 | console_loglevel = 15; | |
100 | printk(" "); | |
101 | console_loglevel = loglevel_save; | |
102 | } | |
103 | } | |
104 | ||
105 | /* | |
482b05dd | 106 | * Returns the address space associated with the fault. |
61365e13 | 107 | * Returns 0 for kernel space and 1 for user space. |
1da177e4 | 108 | */ |
457f2180 | 109 | static inline int user_space_fault(struct pt_regs *regs) |
1da177e4 | 110 | { |
457f2180 HC |
111 | unsigned long trans_exc_code; |
112 | ||
1da177e4 | 113 | /* |
61365e13 MS |
114 | * The lowest two bits of the translation exception |
115 | * identification indicate which paging table was used. | |
1da177e4 | 116 | */ |
457f2180 HC |
117 | trans_exc_code = regs->int_parm_long & 3; |
118 | if (trans_exc_code == 3) /* home space -> kernel */ | |
119 | return 0; | |
120 | if (user_mode(regs)) | |
121 | return 1; | |
122 | if (trans_exc_code == 2) /* secondary space -> set_fs */ | |
61365e13 | 123 | return current->thread.mm_segment.ar4; |
457f2180 HC |
124 | if (current->flags & PF_VCPU) |
125 | return 1; | |
126 | return 0; | |
1da177e4 LT |
127 | } |
128 | ||
3b7df342 HC |
129 | static int bad_address(void *p) |
130 | { | |
131 | unsigned long dummy; | |
132 | ||
133 | return probe_kernel_address((unsigned long *)p, dummy); | |
134 | } | |
135 | ||
136 | #ifdef CONFIG_64BIT | |
137 | static void dump_pagetable(unsigned long asce, unsigned long address) | |
138 | { | |
139 | unsigned long *table = __va(asce & PAGE_MASK); | |
140 | ||
141 | pr_alert("AS:%016lx ", asce); | |
142 | switch (asce & _ASCE_TYPE_MASK) { | |
143 | case _ASCE_TYPE_REGION1: | |
144 | table = table + ((address >> 53) & 0x7ff); | |
145 | if (bad_address(table)) | |
146 | goto bad; | |
147 | pr_cont("R1:%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_REGION2: | |
153 | table = table + ((address >> 42) & 0x7ff); | |
154 | if (bad_address(table)) | |
155 | goto bad; | |
156 | pr_cont("R2:%016lx ", *table); | |
157 | if (*table & _REGION_ENTRY_INVALID) | |
158 | goto out; | |
159 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); | |
160 | /* fallthrough */ | |
161 | case _ASCE_TYPE_REGION3: | |
162 | table = table + ((address >> 31) & 0x7ff); | |
163 | if (bad_address(table)) | |
164 | goto bad; | |
165 | pr_cont("R3:%016lx ", *table); | |
166 | if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) | |
167 | goto out; | |
168 | table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); | |
169 | /* fallthrough */ | |
170 | case _ASCE_TYPE_SEGMENT: | |
171 | table = table + ((address >> 20) & 0x7ff); | |
172 | if (bad_address(table)) | |
173 | goto bad; | |
174 | pr_cont(KERN_CONT "S:%016lx ", *table); | |
175 | if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) | |
176 | goto out; | |
177 | table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); | |
178 | } | |
179 | table = table + ((address >> 12) & 0xff); | |
180 | if (bad_address(table)) | |
181 | goto bad; | |
182 | pr_cont("P:%016lx ", *table); | |
183 | out: | |
184 | pr_cont("\n"); | |
185 | return; | |
186 | bad: | |
187 | pr_cont("BAD\n"); | |
188 | } | |
189 | ||
190 | #else /* CONFIG_64BIT */ | |
191 | ||
192 | static void dump_pagetable(unsigned long asce, unsigned long address) | |
193 | { | |
194 | unsigned long *table = __va(asce & PAGE_MASK); | |
195 | ||
196 | pr_alert("AS:%08lx ", asce); | |
197 | table = table + ((address >> 20) & 0x7ff); | |
198 | if (bad_address(table)) | |
199 | goto bad; | |
200 | pr_cont("S:%08lx ", *table); | |
201 | if (*table & _SEGMENT_ENTRY_INVALID) | |
202 | goto out; | |
203 | table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); | |
204 | table = table + ((address >> 12) & 0xff); | |
205 | if (bad_address(table)) | |
206 | goto bad; | |
207 | pr_cont("P:%08lx ", *table); | |
208 | out: | |
209 | pr_cont("\n"); | |
210 | return; | |
211 | bad: | |
212 | pr_cont("BAD\n"); | |
213 | } | |
214 | ||
215 | #endif /* CONFIG_64BIT */ | |
216 | ||
217 | static void dump_fault_info(struct pt_regs *regs) | |
218 | { | |
219 | unsigned long asce; | |
220 | ||
221 | pr_alert("Fault in "); | |
222 | switch (regs->int_parm_long & 3) { | |
223 | case 3: | |
224 | pr_cont("home space "); | |
225 | break; | |
226 | case 2: | |
227 | pr_cont("secondary space "); | |
228 | break; | |
229 | case 1: | |
230 | pr_cont("access register "); | |
231 | break; | |
232 | case 0: | |
233 | pr_cont("primary space "); | |
234 | break; | |
235 | } | |
236 | pr_cont("mode while using "); | |
237 | if (!user_space_fault(regs)) { | |
238 | asce = S390_lowcore.kernel_asce; | |
239 | pr_cont("kernel "); | |
240 | } | |
241 | #ifdef CONFIG_PGSTE | |
242 | else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { | |
243 | struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; | |
244 | asce = gmap->asce; | |
245 | pr_cont("gmap "); | |
246 | } | |
247 | #endif | |
248 | else { | |
249 | asce = S390_lowcore.user_asce; | |
250 | pr_cont("user "); | |
251 | } | |
252 | pr_cont("ASCE.\n"); | |
253 | dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); | |
254 | } | |
255 | ||
aa33c8cb | 256 | static inline void report_user_fault(struct pt_regs *regs, long signr) |
ab3c68ee HC |
257 | { |
258 | if ((task_pid_nr(current) > 1) && !show_unhandled_signals) | |
259 | return; | |
260 | if (!unhandled_signal(current, signr)) | |
261 | return; | |
262 | if (!printk_ratelimit()) | |
263 | return; | |
aa33c8cb MS |
264 | printk(KERN_ALERT "User process fault: interruption code 0x%X ", |
265 | regs->int_code); | |
ab3c68ee | 266 | print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); |
aa33c8cb | 267 | printk(KERN_CONT "\n"); |
3b7df342 HC |
268 | printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", |
269 | regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); | |
270 | dump_fault_info(regs); | |
ab3c68ee HC |
271 | show_regs(regs); |
272 | } | |
273 | ||
1da177e4 LT |
274 | /* |
275 | * Send SIGSEGV to task. This is an external routine | |
276 | * to keep the stack usage of do_page_fault small. | |
277 | */ | |
aa33c8cb | 278 | static noinline void do_sigsegv(struct pt_regs *regs, int si_code) |
1da177e4 LT |
279 | { |
280 | struct siginfo si; | |
281 | ||
aa33c8cb | 282 | report_user_fault(regs, SIGSEGV); |
1da177e4 LT |
283 | si.si_signo = SIGSEGV; |
284 | si.si_code = si_code; | |
aa33c8cb | 285 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
1da177e4 LT |
286 | force_sig_info(SIGSEGV, &si, current); |
287 | } | |
288 | ||
aa33c8cb | 289 | static noinline void do_no_context(struct pt_regs *regs) |
10c1031f MS |
290 | { |
291 | const struct exception_table_entry *fixup; | |
61365e13 | 292 | unsigned long address; |
10c1031f MS |
293 | |
294 | /* Are we prepared to handle this kernel fault? */ | |
50d7280d | 295 | fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); |
10c1031f | 296 | if (fixup) { |
eb608fb3 | 297 | regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; |
10c1031f MS |
298 | return; |
299 | } | |
300 | ||
301 | /* | |
302 | * Oops. The kernel tried to access some bad page. We'll have to | |
303 | * terminate things with extreme prejudice. | |
304 | */ | |
aa33c8cb | 305 | address = regs->int_parm_long & __FAIL_ADDR_MASK; |
457f2180 | 306 | if (!user_space_fault(regs)) |
10c1031f | 307 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" |
3b7df342 | 308 | " in virtual kernel address space\n"); |
10c1031f MS |
309 | else |
310 | printk(KERN_ALERT "Unable to handle kernel paging request" | |
3b7df342 HC |
311 | " in virtual user address space\n"); |
312 | printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", | |
313 | regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); | |
314 | dump_fault_info(regs); | |
aa33c8cb | 315 | die(regs, "Oops"); |
10c1031f MS |
316 | do_exit(SIGKILL); |
317 | } | |
318 | ||
aa33c8cb | 319 | static noinline void do_low_address(struct pt_regs *regs) |
10c1031f MS |
320 | { |
321 | /* Low-address protection hit in kernel mode means | |
322 | NULL pointer write access in kernel mode. */ | |
323 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
324 | /* Low-address protection hit in user mode 'cannot happen'. */ | |
aa33c8cb | 325 | die (regs, "Low-address protection"); |
10c1031f MS |
326 | do_exit(SIGKILL); |
327 | } | |
328 | ||
aa33c8cb | 329 | do_no_context(regs); |
10c1031f MS |
330 | } |
331 | ||
aa33c8cb | 332 | static noinline void do_sigbus(struct pt_regs *regs) |
10c1031f MS |
333 | { |
334 | struct task_struct *tsk = current; | |
36bf9680 | 335 | struct siginfo si; |
10c1031f | 336 | |
10c1031f MS |
337 | /* |
338 | * Send a sigbus, regardless of whether we were in kernel | |
339 | * or user mode. | |
340 | */ | |
36bf9680 MS |
341 | si.si_signo = SIGBUS; |
342 | si.si_errno = 0; | |
343 | si.si_code = BUS_ADRERR; | |
aa33c8cb | 344 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
36bf9680 | 345 | force_sig_info(SIGBUS, &si, tsk); |
10c1031f MS |
346 | } |
347 | ||
aa33c8cb | 348 | static noinline void do_fault_error(struct pt_regs *regs, int fault) |
50d7280d MS |
349 | { |
350 | int si_code; | |
351 | ||
352 | switch (fault) { | |
353 | case VM_FAULT_BADACCESS: | |
50d7280d MS |
354 | case VM_FAULT_BADMAP: |
355 | /* Bad memory access. Check if it is kernel or user space. */ | |
7d256175 | 356 | if (user_mode(regs)) { |
50d7280d MS |
357 | /* User mode accesses just cause a SIGSEGV */ |
358 | si_code = (fault == VM_FAULT_BADMAP) ? | |
359 | SEGV_MAPERR : SEGV_ACCERR; | |
aa33c8cb | 360 | do_sigsegv(regs, si_code); |
50d7280d MS |
361 | return; |
362 | } | |
363 | case VM_FAULT_BADCONTEXT: | |
24eb3a82 | 364 | case VM_FAULT_PFAULT: |
aa33c8cb | 365 | do_no_context(regs); |
50d7280d | 366 | break; |
f2c76e3b HC |
367 | case VM_FAULT_SIGNAL: |
368 | if (!user_mode(regs)) | |
369 | do_no_context(regs); | |
370 | break; | |
50d7280d | 371 | default: /* fault & VM_FAULT_ERROR */ |
99583181 | 372 | if (fault & VM_FAULT_OOM) { |
7d256175 | 373 | if (!user_mode(regs)) |
aa33c8cb | 374 | do_no_context(regs); |
99583181 HC |
375 | else |
376 | pagefault_out_of_memory(); | |
377 | } else if (fault & VM_FAULT_SIGBUS) { | |
50d7280d | 378 | /* Kernel mode? Handle exceptions or die */ |
7d256175 | 379 | if (!user_mode(regs)) |
aa33c8cb | 380 | do_no_context(regs); |
36bf9680 | 381 | else |
aa33c8cb | 382 | do_sigbus(regs); |
50d7280d MS |
383 | } else |
384 | BUG(); | |
385 | break; | |
386 | } | |
387 | } | |
388 | ||
1da177e4 LT |
389 | /* |
390 | * This routine handles page faults. It determines the address, | |
391 | * and the problem, and then passes it off to one of the appropriate | |
392 | * routines. | |
393 | * | |
50d7280d | 394 | * interruption code (int_code): |
1da177e4 LT |
395 | * 04 Protection -> Write-Protection (suprression) |
396 | * 10 Segment translation -> Not present (nullification) | |
397 | * 11 Page translation -> Not present (nullification) | |
398 | * 3b Region third trans. -> Not present (nullification) | |
399 | */ | |
aa33c8cb | 400 | static inline int do_exception(struct pt_regs *regs, int access) |
1da177e4 | 401 | { |
24eb3a82 DD |
402 | #ifdef CONFIG_PGSTE |
403 | struct gmap *gmap; | |
404 | #endif | |
10c1031f MS |
405 | struct task_struct *tsk; |
406 | struct mm_struct *mm; | |
407 | struct vm_area_struct *vma; | |
aa33c8cb | 408 | unsigned long trans_exc_code; |
10c1031f | 409 | unsigned long address; |
33ce6140 HC |
410 | unsigned int flags; |
411 | int fault; | |
1da177e4 | 412 | |
39efd4ec MS |
413 | tsk = current; |
414 | /* | |
415 | * The instruction that caused the program check has | |
416 | * been nullified. Don't signal single step via SIGTRAP. | |
417 | */ | |
d3a73acb | 418 | clear_pt_regs_flag(regs, PIF_PER_TRAP); |
39efd4ec | 419 | |
7ecb344a | 420 | if (notify_page_fault(regs)) |
50d7280d | 421 | return 0; |
4ba069b8 | 422 | |
10c1031f | 423 | mm = tsk->mm; |
aa33c8cb | 424 | trans_exc_code = regs->int_parm_long; |
1da177e4 | 425 | |
1da177e4 LT |
426 | /* |
427 | * Verify that the fault happened in user space, that | |
428 | * we are not in an interrupt and that there is a | |
429 | * user context. | |
430 | */ | |
50d7280d | 431 | fault = VM_FAULT_BADCONTEXT; |
457f2180 | 432 | if (unlikely(!user_space_fault(regs) || in_atomic() || !mm)) |
50d7280d | 433 | goto out; |
1da177e4 | 434 | |
61365e13 | 435 | address = trans_exc_code & __FAIL_ADDR_MASK; |
a8b0ca17 | 436 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
f2c76e3b | 437 | flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
759496ba JW |
438 | if (user_mode(regs)) |
439 | flags |= FAULT_FLAG_USER; | |
33ce6140 HC |
440 | if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) |
441 | flags |= FAULT_FLAG_WRITE; | |
10c1031f | 442 | down_read(&mm->mmap_sem); |
1da177e4 | 443 | |
e5992f2e | 444 | #ifdef CONFIG_PGSTE |
24eb3a82 DD |
445 | gmap = (struct gmap *) |
446 | ((current->flags & PF_VCPU) ? S390_lowcore.gmap : 0); | |
447 | if (gmap) { | |
6e0a0431 | 448 | address = __gmap_fault(gmap, address); |
e5992f2e MS |
449 | if (address == -EFAULT) { |
450 | fault = VM_FAULT_BADMAP; | |
451 | goto out_up; | |
452 | } | |
453 | if (address == -ENOMEM) { | |
454 | fault = VM_FAULT_OOM; | |
455 | goto out_up; | |
456 | } | |
24eb3a82 DD |
457 | if (gmap->pfault_enabled) |
458 | flags |= FAULT_FLAG_RETRY_NOWAIT; | |
e5992f2e MS |
459 | } |
460 | #endif | |
461 | ||
462 | retry: | |
50d7280d | 463 | fault = VM_FAULT_BADMAP; |
482b05dd GS |
464 | vma = find_vma(mm, address); |
465 | if (!vma) | |
50d7280d | 466 | goto out_up; |
c1821c2e | 467 | |
50d7280d MS |
468 | if (unlikely(vma->vm_start > address)) { |
469 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
470 | goto out_up; | |
471 | if (expand_stack(vma, address)) | |
472 | goto out_up; | |
473 | } | |
474 | ||
475 | /* | |
476 | * Ok, we have a good vm_area for this memory access, so | |
477 | * we can handle it.. | |
478 | */ | |
479 | fault = VM_FAULT_BADACCESS; | |
1ab947de | 480 | if (unlikely(!(vma->vm_flags & access))) |
50d7280d | 481 | goto out_up; |
1da177e4 | 482 | |
53492b1d GS |
483 | if (is_vm_hugetlb_page(vma)) |
484 | address &= HPAGE_MASK; | |
1da177e4 LT |
485 | /* |
486 | * If for any reason at all we couldn't handle the fault, | |
487 | * make sure we exit gracefully rather than endlessly redo | |
488 | * the fault. | |
489 | */ | |
33ce6140 | 490 | fault = handle_mm_fault(mm, vma, address, flags); |
f2c76e3b HC |
491 | /* No reason to continue if interrupted by SIGKILL. */ |
492 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { | |
493 | fault = VM_FAULT_SIGNAL; | |
494 | goto out; | |
495 | } | |
50d7280d MS |
496 | if (unlikely(fault & VM_FAULT_ERROR)) |
497 | goto out_up; | |
498 | ||
33ce6140 HC |
499 | /* |
500 | * Major/minor page fault accounting is only done on the | |
501 | * initial attempt. If we go through a retry, it is extremely | |
502 | * likely that the page will be found in page cache at that point. | |
503 | */ | |
504 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
505 | if (fault & VM_FAULT_MAJOR) { | |
506 | tsk->maj_flt++; | |
a8b0ca17 | 507 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, |
33ce6140 HC |
508 | regs, address); |
509 | } else { | |
510 | tsk->min_flt++; | |
a8b0ca17 | 511 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, |
33ce6140 HC |
512 | regs, address); |
513 | } | |
514 | if (fault & VM_FAULT_RETRY) { | |
24eb3a82 DD |
515 | #ifdef CONFIG_PGSTE |
516 | if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { | |
517 | /* FAULT_FLAG_RETRY_NOWAIT has been set, | |
518 | * mmap_sem has not been released */ | |
519 | current->thread.gmap_pfault = 1; | |
520 | fault = VM_FAULT_PFAULT; | |
521 | goto out_up; | |
522 | } | |
523 | #endif | |
33ce6140 HC |
524 | /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk |
525 | * of starvation. */ | |
24eb3a82 DD |
526 | flags &= ~(FAULT_FLAG_ALLOW_RETRY | |
527 | FAULT_FLAG_RETRY_NOWAIT); | |
45cac65b | 528 | flags |= FAULT_FLAG_TRIED; |
e5992f2e | 529 | down_read(&mm->mmap_sem); |
33ce6140 HC |
530 | goto retry; |
531 | } | |
bde69af2 | 532 | } |
50d7280d MS |
533 | fault = 0; |
534 | out_up: | |
10c1031f | 535 | up_read(&mm->mmap_sem); |
50d7280d MS |
536 | out: |
537 | return fault; | |
1da177e4 LT |
538 | } |
539 | ||
aa33c8cb | 540 | void __kprobes do_protection_exception(struct pt_regs *regs) |
1da177e4 | 541 | { |
aa33c8cb | 542 | unsigned long trans_exc_code; |
50d7280d | 543 | int fault; |
61365e13 | 544 | |
aa33c8cb | 545 | trans_exc_code = regs->int_parm_long; |
f752ac4d MS |
546 | /* |
547 | * Protection exceptions are suppressing, decrement psw address. | |
548 | * The exception to this rule are aborted transactions, for these | |
549 | * the PSW already points to the correct location. | |
550 | */ | |
551 | if (!(regs->int_code & 0x200)) | |
552 | regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); | |
10c1031f MS |
553 | /* |
554 | * Check for low-address protection. This needs to be treated | |
555 | * as a special case because the translation exception code | |
556 | * field is not guaranteed to contain valid data in this case. | |
557 | */ | |
61365e13 | 558 | if (unlikely(!(trans_exc_code & 4))) { |
aa33c8cb | 559 | do_low_address(regs); |
10c1031f MS |
560 | return; |
561 | } | |
aa33c8cb | 562 | fault = do_exception(regs, VM_WRITE); |
50d7280d | 563 | if (unlikely(fault)) |
aa33c8cb | 564 | do_fault_error(regs, fault); |
1da177e4 LT |
565 | } |
566 | ||
aa33c8cb | 567 | void __kprobes do_dat_exception(struct pt_regs *regs) |
1da177e4 | 568 | { |
1ab947de | 569 | int access, fault; |
50d7280d | 570 | |
1ab947de | 571 | access = VM_READ | VM_EXEC | VM_WRITE; |
aa33c8cb | 572 | fault = do_exception(regs, access); |
50d7280d | 573 | if (unlikely(fault)) |
aa33c8cb | 574 | do_fault_error(regs, fault); |
1da177e4 LT |
575 | } |
576 | ||
1da177e4 LT |
577 | #ifdef CONFIG_PFAULT |
578 | /* | |
579 | * 'pfault' pseudo page faults routines. | |
580 | */ | |
fb0a9d7e | 581 | static int pfault_disable; |
1da177e4 LT |
582 | |
583 | static int __init nopfault(char *str) | |
584 | { | |
585 | pfault_disable = 1; | |
586 | return 1; | |
587 | } | |
588 | ||
589 | __setup("nopfault", nopfault); | |
590 | ||
7dd8fe1f HC |
591 | struct pfault_refbk { |
592 | u16 refdiagc; | |
593 | u16 reffcode; | |
594 | u16 refdwlen; | |
595 | u16 refversn; | |
596 | u64 refgaddr; | |
597 | u64 refselmk; | |
598 | u64 refcmpmk; | |
599 | u64 reserved; | |
600 | } __attribute__ ((packed, aligned(8))); | |
1da177e4 LT |
601 | |
602 | int pfault_init(void) | |
603 | { | |
7dd8fe1f HC |
604 | struct pfault_refbk refbk = { |
605 | .refdiagc = 0x258, | |
606 | .reffcode = 0, | |
607 | .refdwlen = 5, | |
608 | .refversn = 2, | |
609 | .refgaddr = __LC_CURRENT_PID, | |
610 | .refselmk = 1ULL << 48, | |
611 | .refcmpmk = 1ULL << 48, | |
612 | .reserved = __PF_RES_FIELD }; | |
1da177e4 LT |
613 | int rc; |
614 | ||
f32269a0 | 615 | if (pfault_disable) |
1da177e4 | 616 | return -1; |
94c12cc7 MS |
617 | asm volatile( |
618 | " diag %1,%0,0x258\n" | |
619 | "0: j 2f\n" | |
620 | "1: la %0,8\n" | |
1da177e4 | 621 | "2:\n" |
94c12cc7 MS |
622 | EX_TABLE(0b,1b) |
623 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
624 | return rc; |
625 | } | |
626 | ||
627 | void pfault_fini(void) | |
628 | { | |
7dd8fe1f HC |
629 | struct pfault_refbk refbk = { |
630 | .refdiagc = 0x258, | |
631 | .reffcode = 1, | |
632 | .refdwlen = 5, | |
633 | .refversn = 2, | |
634 | }; | |
1da177e4 | 635 | |
f32269a0 | 636 | if (pfault_disable) |
1da177e4 | 637 | return; |
94c12cc7 MS |
638 | asm volatile( |
639 | " diag %0,0,0x258\n" | |
1da177e4 | 640 | "0:\n" |
94c12cc7 MS |
641 | EX_TABLE(0b,0b) |
642 | : : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
643 | } |
644 | ||
f2db2e6c HC |
645 | static DEFINE_SPINLOCK(pfault_lock); |
646 | static LIST_HEAD(pfault_list); | |
647 | ||
fde15c3a | 648 | static void pfault_interrupt(struct ext_code ext_code, |
f6649a7e | 649 | unsigned int param32, unsigned long param64) |
1da177e4 LT |
650 | { |
651 | struct task_struct *tsk; | |
652 | __u16 subcode; | |
f2db2e6c | 653 | pid_t pid; |
1da177e4 LT |
654 | |
655 | /* | |
656 | * Get the external interruption subcode & pfault | |
657 | * initial/completion signal bit. VM stores this | |
658 | * in the 'cpu address' field associated with the | |
659 | * external interrupt. | |
660 | */ | |
fde15c3a | 661 | subcode = ext_code.subcode; |
1da177e4 LT |
662 | if ((subcode & 0xff00) != __SUBCODE_MASK) |
663 | return; | |
420f42ec | 664 | inc_irq_stat(IRQEXT_PFL); |
54c27791 HC |
665 | /* Get the token (= pid of the affected task). */ |
666 | pid = sizeof(void *) == 4 ? param32 : param64; | |
667 | rcu_read_lock(); | |
668 | tsk = find_task_by_pid_ns(pid, &init_pid_ns); | |
669 | if (tsk) | |
670 | get_task_struct(tsk); | |
671 | rcu_read_unlock(); | |
672 | if (!tsk) | |
673 | return; | |
f2db2e6c | 674 | spin_lock(&pfault_lock); |
1da177e4 LT |
675 | if (subcode & 0x0080) { |
676 | /* signal bit is set -> a page has been swapped in by VM */ | |
f2db2e6c | 677 | if (tsk->thread.pfault_wait == 1) { |
1da177e4 LT |
678 | /* Initial interrupt was faster than the completion |
679 | * interrupt. pfault_wait is valid. Set pfault_wait | |
680 | * back to zero and wake up the process. This can | |
681 | * safely be done because the task is still sleeping | |
b6d09449 | 682 | * and can't produce new pfaults. */ |
1da177e4 | 683 | tsk->thread.pfault_wait = 0; |
f2db2e6c | 684 | list_del(&tsk->thread.list); |
1da177e4 | 685 | wake_up_process(tsk); |
d5e50a51 | 686 | put_task_struct(tsk); |
f2db2e6c HC |
687 | } else { |
688 | /* Completion interrupt was faster than initial | |
689 | * interrupt. Set pfault_wait to -1 so the initial | |
fa2fb2f4 HC |
690 | * interrupt doesn't put the task to sleep. |
691 | * If the task is not running, ignore the completion | |
692 | * interrupt since it must be a leftover of a PFAULT | |
693 | * CANCEL operation which didn't remove all pending | |
694 | * completion interrupts. */ | |
695 | if (tsk->state == TASK_RUNNING) | |
696 | tsk->thread.pfault_wait = -1; | |
1da177e4 LT |
697 | } |
698 | } else { | |
699 | /* signal bit not set -> a real page is missing. */ | |
d49f47f8 HC |
700 | if (WARN_ON_ONCE(tsk != current)) |
701 | goto out; | |
d5e50a51 HC |
702 | if (tsk->thread.pfault_wait == 1) { |
703 | /* Already on the list with a reference: put to sleep */ | |
0a16ba78 | 704 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
d5e50a51 HC |
705 | set_tsk_need_resched(tsk); |
706 | } else if (tsk->thread.pfault_wait == -1) { | |
1da177e4 | 707 | /* Completion interrupt was faster than the initial |
f2db2e6c HC |
708 | * interrupt (pfault_wait == -1). Set pfault_wait |
709 | * back to zero and exit. */ | |
1da177e4 | 710 | tsk->thread.pfault_wait = 0; |
f2db2e6c HC |
711 | } else { |
712 | /* Initial interrupt arrived before completion | |
d5e50a51 HC |
713 | * interrupt. Let the task sleep. |
714 | * An extra task reference is needed since a different | |
715 | * cpu may set the task state to TASK_RUNNING again | |
716 | * before the scheduler is reached. */ | |
717 | get_task_struct(tsk); | |
f2db2e6c HC |
718 | tsk->thread.pfault_wait = 1; |
719 | list_add(&tsk->thread.list, &pfault_list); | |
0a16ba78 | 720 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
1da177e4 | 721 | set_tsk_need_resched(tsk); |
f2db2e6c HC |
722 | } |
723 | } | |
d49f47f8 | 724 | out: |
f2db2e6c | 725 | spin_unlock(&pfault_lock); |
54c27791 | 726 | put_task_struct(tsk); |
f2db2e6c HC |
727 | } |
728 | ||
e2741f17 PG |
729 | static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, |
730 | void *hcpu) | |
f2db2e6c HC |
731 | { |
732 | struct thread_struct *thread, *next; | |
733 | struct task_struct *tsk; | |
734 | ||
1c725922 | 735 | switch (action & ~CPU_TASKS_FROZEN) { |
f2db2e6c | 736 | case CPU_DEAD: |
f2db2e6c HC |
737 | spin_lock_irq(&pfault_lock); |
738 | list_for_each_entry_safe(thread, next, &pfault_list, list) { | |
739 | thread->pfault_wait = 0; | |
740 | list_del(&thread->list); | |
741 | tsk = container_of(thread, struct task_struct, thread); | |
742 | wake_up_process(tsk); | |
d5e50a51 | 743 | put_task_struct(tsk); |
f2db2e6c HC |
744 | } |
745 | spin_unlock_irq(&pfault_lock); | |
746 | break; | |
747 | default: | |
748 | break; | |
1da177e4 | 749 | } |
f2db2e6c | 750 | return NOTIFY_OK; |
1da177e4 | 751 | } |
1da177e4 | 752 | |
fb0a9d7e | 753 | static int __init pfault_irq_init(void) |
29b08d2b | 754 | { |
fb0a9d7e | 755 | int rc; |
29b08d2b | 756 | |
1dad093b | 757 | rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); |
7dd8fe1f HC |
758 | if (rc) |
759 | goto out_extint; | |
760 | rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; | |
761 | if (rc) | |
762 | goto out_pfault; | |
82003c3e | 763 | irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); |
7dd8fe1f HC |
764 | hotcpu_notifier(pfault_cpu_notify, 0); |
765 | return 0; | |
29b08d2b | 766 | |
7dd8fe1f | 767 | out_pfault: |
1dad093b | 768 | unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); |
7dd8fe1f HC |
769 | out_extint: |
770 | pfault_disable = 1; | |
771 | return rc; | |
29b08d2b | 772 | } |
fb0a9d7e HC |
773 | early_initcall(pfault_irq_init); |
774 | ||
7dd8fe1f | 775 | #endif /* CONFIG_PFAULT */ |