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14#include <linux/kernel.h>
15#include <linux/mm.h>
16#include <linux/hardirq.h>
17#include <linux/kprobes.h>
18#include <linux/perf_event.h>
19#include <linux/kdebug.h>
20#include <asm/io_trapped.h>
21#include <asm/mmu_context.h>
22#include <asm/tlbflush.h>
23#include <asm/traps.h>
24
25static inline int notify_page_fault(struct pt_regs *regs, int trap)
26{
27 int ret = 0;
28
29 if (kprobes_built_in() && !user_mode(regs)) {
30 preempt_disable();
31 if (kprobe_running() && kprobe_fault_handler(regs, trap))
32 ret = 1;
33 preempt_enable();
34 }
35
36 return ret;
37}
38
39static void
40force_sig_info_fault(int si_signo, int si_code, unsigned long address,
41 struct task_struct *tsk)
42{
43 siginfo_t info;
44
45 info.si_signo = si_signo;
46 info.si_errno = 0;
47 info.si_code = si_code;
48 info.si_addr = (void __user *)address;
49
50 force_sig_info(si_signo, &info, tsk);
51}
52
53
54
55
56
57static void show_pte(struct mm_struct *mm, unsigned long addr)
58{
59 pgd_t *pgd;
60
61 if (mm) {
62 pgd = mm->pgd;
63 } else {
64 pgd = get_TTB();
65
66 if (unlikely(!pgd))
67 pgd = swapper_pg_dir;
68 }
69
70 printk(KERN_ALERT "pgd = %p\n", pgd);
71 pgd += pgd_index(addr);
72 printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr,
73 (u32)(sizeof(*pgd) * 2), (u64)pgd_val(*pgd));
74
75 do {
76 pud_t *pud;
77 pmd_t *pmd;
78 pte_t *pte;
79
80 if (pgd_none(*pgd))
81 break;
82
83 if (pgd_bad(*pgd)) {
84 printk("(bad)");
85 break;
86 }
87
88 pud = pud_offset(pgd, addr);
89 if (PTRS_PER_PUD != 1)
90 printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2),
91 (u64)pud_val(*pud));
92
93 if (pud_none(*pud))
94 break;
95
96 if (pud_bad(*pud)) {
97 printk("(bad)");
98 break;
99 }
100
101 pmd = pmd_offset(pud, addr);
102 if (PTRS_PER_PMD != 1)
103 printk(", *pmd=%0*Lx", (u32)(sizeof(*pmd) * 2),
104 (u64)pmd_val(*pmd));
105
106 if (pmd_none(*pmd))
107 break;
108
109 if (pmd_bad(*pmd)) {
110 printk("(bad)");
111 break;
112 }
113
114
115 if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
116 break;
117
118 pte = pte_offset_kernel(pmd, addr);
119 printk(", *pte=%0*Lx", (u32)(sizeof(*pte) * 2),
120 (u64)pte_val(*pte));
121 } while (0);
122
123 printk("\n");
124}
125
126static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
127{
128 unsigned index = pgd_index(address);
129 pgd_t *pgd_k;
130 pud_t *pud, *pud_k;
131 pmd_t *pmd, *pmd_k;
132
133 pgd += index;
134 pgd_k = init_mm.pgd + index;
135
136 if (!pgd_present(*pgd_k))
137 return NULL;
138
139 pud = pud_offset(pgd, address);
140 pud_k = pud_offset(pgd_k, address);
141 if (!pud_present(*pud_k))
142 return NULL;
143
144 if (!pud_present(*pud))
145 set_pud(pud, *pud_k);
146
147 pmd = pmd_offset(pud, address);
148 pmd_k = pmd_offset(pud_k, address);
149 if (!pmd_present(*pmd_k))
150 return NULL;
151
152 if (!pmd_present(*pmd))
153 set_pmd(pmd, *pmd_k);
154 else {
155
156
157
158
159
160 BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
161 return NULL;
162 }
163
164 return pmd_k;
165}
166
167#ifdef CONFIG_SH_STORE_QUEUES
168#define __FAULT_ADDR_LIMIT P3_ADDR_MAX
169#else
170#define __FAULT_ADDR_LIMIT VMALLOC_END
171#endif
172
173
174
175
176static noinline int vmalloc_fault(unsigned long address)
177{
178 pgd_t *pgd_k;
179 pmd_t *pmd_k;
180 pte_t *pte_k;
181
182
183 if (!(address >= VMALLOC_START && address < __FAULT_ADDR_LIMIT))
184 return -1;
185
186
187
188
189
190
191
192
193 pgd_k = get_TTB();
194 pmd_k = vmalloc_sync_one(pgd_k, address);
195 if (!pmd_k)
196 return -1;
197
198 pte_k = pte_offset_kernel(pmd_k, address);
199 if (!pte_present(*pte_k))
200 return -1;
201
202 return 0;
203}
204
205static void
206show_fault_oops(struct pt_regs *regs, unsigned long address)
207{
208 if (!oops_may_print())
209 return;
210
211 printk(KERN_ALERT "BUG: unable to handle kernel ");
212 if (address < PAGE_SIZE)
213 printk(KERN_CONT "NULL pointer dereference");
214 else
215 printk(KERN_CONT "paging request");
216
217 printk(KERN_CONT " at %08lx\n", address);
218 printk(KERN_ALERT "PC:");
219 printk_address(regs->pc, 1);
220
221 show_pte(NULL, address);
222}
223
224static noinline void
225no_context(struct pt_regs *regs, unsigned long error_code,
226 unsigned long address)
227{
228
229 if (fixup_exception(regs))
230 return;
231
232 if (handle_trapped_io(regs, address))
233 return;
234
235
236
237
238
239 bust_spinlocks(1);
240
241 show_fault_oops(regs, address);
242
243 die("Oops", regs, error_code);
244 bust_spinlocks(0);
245 do_exit(SIGKILL);
246}
247
248static void
249__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
250 unsigned long address, int si_code)
251{
252 struct task_struct *tsk = current;
253
254
255 if (user_mode(regs)) {
256
257
258
259 local_irq_enable();
260
261 force_sig_info_fault(SIGSEGV, si_code, address, tsk);
262
263 return;
264 }
265
266 no_context(regs, error_code, address);
267}
268
269static noinline void
270bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
271 unsigned long address)
272{
273 __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
274}
275
276static void
277__bad_area(struct pt_regs *regs, unsigned long error_code,
278 unsigned long address, int si_code)
279{
280 struct mm_struct *mm = current->mm;
281
282
283
284
285
286 up_read(&mm->mmap_sem);
287
288 __bad_area_nosemaphore(regs, error_code, address, si_code);
289}
290
291static noinline void
292bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
293{
294 __bad_area(regs, error_code, address, SEGV_MAPERR);
295}
296
297static noinline void
298bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
299 unsigned long address)
300{
301 __bad_area(regs, error_code, address, SEGV_ACCERR);
302}
303
304static void out_of_memory(void)
305{
306
307
308
309
310 up_read(¤t->mm->mmap_sem);
311
312 pagefault_out_of_memory();
313}
314
315static void
316do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
317{
318 struct task_struct *tsk = current;
319 struct mm_struct *mm = tsk->mm;
320
321 up_read(&mm->mmap_sem);
322
323
324 if (!user_mode(regs))
325 no_context(regs, error_code, address);
326
327 force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
328}
329
330static noinline int
331mm_fault_error(struct pt_regs *regs, unsigned long error_code,
332 unsigned long address, unsigned int fault)
333{
334
335
336
337
338 if (fatal_signal_pending(current)) {
339 if (!(fault & VM_FAULT_RETRY))
340 up_read(¤t->mm->mmap_sem);
341 if (!user_mode(regs))
342 no_context(regs, error_code, address);
343 return 1;
344 }
345
346 if (!(fault & VM_FAULT_ERROR))
347 return 0;
348
349 if (fault & VM_FAULT_OOM) {
350
351 if (!user_mode(regs)) {
352 up_read(¤t->mm->mmap_sem);
353 no_context(regs, error_code, address);
354 return 1;
355 }
356
357 out_of_memory();
358 } else {
359 if (fault & VM_FAULT_SIGBUS)
360 do_sigbus(regs, error_code, address);
361 else
362 BUG();
363 }
364
365 return 1;
366}
367
368static inline int access_error(int error_code, struct vm_area_struct *vma)
369{
370 if (error_code & FAULT_CODE_WRITE) {
371
372 if (unlikely(!(vma->vm_flags & VM_WRITE)))
373 return 1;
374 return 0;
375 }
376
377
378 if (unlikely((error_code & FAULT_CODE_ITLB) &&
379 !(vma->vm_flags & VM_EXEC)))
380 return 1;
381
382
383 if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
384 return 1;
385
386 return 0;
387}
388
389static int fault_in_kernel_space(unsigned long address)
390{
391 return address >= TASK_SIZE;
392}
393
394
395
396
397
398
399asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
400 unsigned long error_code,
401 unsigned long address)
402{
403 unsigned long vec;
404 struct task_struct *tsk;
405 struct mm_struct *mm;
406 struct vm_area_struct * vma;
407 int fault;
408 int write = error_code & FAULT_CODE_WRITE;
409 unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
410 (write ? FAULT_FLAG_WRITE : 0));
411
412 tsk = current;
413 mm = tsk->mm;
414 vec = lookup_exception_vector();
415
416
417
418
419
420
421
422
423
424
425 if (unlikely(fault_in_kernel_space(address))) {
426 if (vmalloc_fault(address) >= 0)
427 return;
428 if (notify_page_fault(regs, vec))
429 return;
430
431 bad_area_nosemaphore(regs, error_code, address);
432 return;
433 }
434
435 if (unlikely(notify_page_fault(regs, vec)))
436 return;
437
438
439 if ((regs->sr & SR_IMASK) != SR_IMASK)
440 local_irq_enable();
441
442 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
443
444
445
446
447
448 if (unlikely(in_atomic() || !mm)) {
449 bad_area_nosemaphore(regs, error_code, address);
450 return;
451 }
452
453retry:
454 down_read(&mm->mmap_sem);
455
456 vma = find_vma(mm, address);
457 if (unlikely(!vma)) {
458 bad_area(regs, error_code, address);
459 return;
460 }
461 if (likely(vma->vm_start <= address))
462 goto good_area;
463 if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
464 bad_area(regs, error_code, address);
465 return;
466 }
467 if (unlikely(expand_stack(vma, address))) {
468 bad_area(regs, error_code, address);
469 return;
470 }
471
472
473
474
475
476good_area:
477 if (unlikely(access_error(error_code, vma))) {
478 bad_area_access_error(regs, error_code, address);
479 return;
480 }
481
482 set_thread_fault_code(error_code);
483
484
485
486
487
488
489 fault = handle_mm_fault(mm, vma, address, flags);
490
491 if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
492 if (mm_fault_error(regs, error_code, address, fault))
493 return;
494
495 if (flags & FAULT_FLAG_ALLOW_RETRY) {
496 if (fault & VM_FAULT_MAJOR) {
497 tsk->maj_flt++;
498 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
499 regs, address);
500 } else {
501 tsk->min_flt++;
502 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
503 regs, address);
504 }
505 if (fault & VM_FAULT_RETRY) {
506 flags &= ~FAULT_FLAG_ALLOW_RETRY;
507
508
509
510
511
512
513 goto retry;
514 }
515 }
516
517 up_read(&mm->mmap_sem);
518}
519