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9#include <linux/extable.h>
10#include <linux/signal.h>
11#include <linux/mm.h>
12#include <linux/hardirq.h>
13#include <linux/init.h>
14#include <linux/kprobes.h>
15#include <linux/uaccess.h>
16#include <linux/page-flags.h>
17#include <linux/sched/signal.h>
18#include <linux/io.h>
19
20#include <asm/pgtable.h>
21#include <asm/tlbflush.h>
22
23
24
25
26#define FSR_LNX_PF (1 << 31)
27
28static inline int fsr_fs(unsigned int fsr)
29{
30
31 return (fsr & 31) + ((fsr & (3 << 5)) >> 5);
32}
33
34
35
36
37
38void show_pte(struct mm_struct *mm, unsigned long addr)
39{
40 pgd_t *pgd;
41
42 if (!mm)
43 mm = &init_mm;
44
45 printk(KERN_ALERT "pgd = %p\n", mm->pgd);
46 pgd = pgd_offset(mm, addr);
47 printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
48
49 do {
50 pmd_t *pmd;
51 pte_t *pte;
52
53 if (pgd_none(*pgd))
54 break;
55
56 if (pgd_bad(*pgd)) {
57 printk("(bad)");
58 break;
59 }
60
61 pmd = pmd_offset((pud_t *) pgd, addr);
62 if (PTRS_PER_PMD != 1)
63 printk(", *pmd=%08lx", pmd_val(*pmd));
64
65 if (pmd_none(*pmd))
66 break;
67
68 if (pmd_bad(*pmd)) {
69 printk("(bad)");
70 break;
71 }
72
73
74 if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
75 break;
76
77 pte = pte_offset_map(pmd, addr);
78 printk(", *pte=%08lx", pte_val(*pte));
79 pte_unmap(pte);
80 } while (0);
81
82 printk("\n");
83}
84
85
86
87
88static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
89 unsigned int fsr, struct pt_regs *regs)
90{
91
92
93
94 if (fixup_exception(regs))
95 return;
96
97
98
99
100 bust_spinlocks(1);
101 printk(KERN_ALERT
102 "Unable to handle kernel %s at virtual address %08lx\n",
103 (addr < PAGE_SIZE) ? "NULL pointer dereference" :
104 "paging request", addr);
105
106 show_pte(mm, addr);
107 die("Oops", regs, fsr);
108 bust_spinlocks(0);
109 do_exit(SIGKILL);
110}
111
112
113
114
115
116static void __do_user_fault(unsigned long addr, unsigned int fsr,
117 unsigned int sig, int code, struct pt_regs *regs)
118{
119 struct task_struct *tsk = current;
120
121 tsk->thread.address = addr;
122 tsk->thread.error_code = fsr;
123 tsk->thread.trap_no = 14;
124 force_sig_fault(sig, code, (void __user *)addr);
125}
126
127void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
128{
129 struct task_struct *tsk = current;
130 struct mm_struct *mm = tsk->active_mm;
131
132
133
134
135
136 if (user_mode(regs))
137 __do_user_fault(addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
138 else
139 __do_kernel_fault(mm, addr, fsr, regs);
140}
141
142#define VM_FAULT_BADMAP 0x010000
143#define VM_FAULT_BADACCESS 0x020000
144
145
146
147
148
149
150static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
151{
152 unsigned int mask = VM_ACCESS_FLAGS;
153
154 if (!(fsr ^ 0x12))
155 mask = VM_WRITE;
156 if (fsr & FSR_LNX_PF)
157 mask = VM_EXEC;
158
159 return vma->vm_flags & mask ? false : true;
160}
161
162static vm_fault_t __do_pf(struct mm_struct *mm, unsigned long addr,
163 unsigned int fsr, unsigned int flags, struct task_struct *tsk)
164{
165 struct vm_area_struct *vma;
166 vm_fault_t fault;
167
168 vma = find_vma(mm, addr);
169 fault = VM_FAULT_BADMAP;
170 if (unlikely(!vma))
171 goto out;
172 if (unlikely(vma->vm_start > addr))
173 goto check_stack;
174
175
176
177
178
179good_area:
180 if (access_error(fsr, vma)) {
181 fault = VM_FAULT_BADACCESS;
182 goto out;
183 }
184
185
186
187
188
189 fault = handle_mm_fault(vma, addr & PAGE_MASK, flags);
190 return fault;
191
192check_stack:
193 if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
194 goto good_area;
195out:
196 return fault;
197}
198
199static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
200{
201 struct task_struct *tsk;
202 struct mm_struct *mm;
203 int sig, code;
204 vm_fault_t fault;
205 unsigned int flags = FAULT_FLAG_DEFAULT;
206
207 tsk = current;
208 mm = tsk->mm;
209
210
211
212
213
214 if (faulthandler_disabled() || !mm)
215 goto no_context;
216
217 if (user_mode(regs))
218 flags |= FAULT_FLAG_USER;
219 if (!(fsr ^ 0x12))
220 flags |= FAULT_FLAG_WRITE;
221
222
223
224
225
226
227 if (!down_read_trylock(&mm->mmap_sem)) {
228 if (!user_mode(regs)
229 && !search_exception_tables(regs->UCreg_pc))
230 goto no_context;
231retry:
232 down_read(&mm->mmap_sem);
233 } else {
234
235
236
237
238
239 might_sleep();
240#ifdef CONFIG_DEBUG_VM
241 if (!user_mode(regs) &&
242 !search_exception_tables(regs->UCreg_pc))
243 goto no_context;
244#endif
245 }
246
247 fault = __do_pf(mm, addr, fsr, flags, tsk);
248
249
250
251
252
253 if (fault_signal_pending(fault, regs))
254 return 0;
255
256 if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) {
257 if (fault & VM_FAULT_MAJOR)
258 tsk->maj_flt++;
259 else
260 tsk->min_flt++;
261 if (fault & VM_FAULT_RETRY) {
262 flags |= FAULT_FLAG_TRIED;
263 goto retry;
264 }
265 }
266
267 up_read(&mm->mmap_sem);
268
269
270
271
272 if (likely(!(fault &
273 (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
274 return 0;
275
276
277
278
279
280 if (!user_mode(regs))
281 goto no_context;
282
283 if (fault & VM_FAULT_OOM) {
284
285
286
287
288
289 pagefault_out_of_memory();
290 return 0;
291 }
292
293 if (fault & VM_FAULT_SIGBUS) {
294
295
296
297
298 sig = SIGBUS;
299 code = BUS_ADRERR;
300 } else {
301
302
303
304
305 sig = SIGSEGV;
306 code = fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR;
307 }
308
309 __do_user_fault(addr, fsr, sig, code, regs);
310 return 0;
311
312no_context:
313 __do_kernel_fault(mm, addr, fsr, regs);
314 return 0;
315}
316
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333
334static int do_ifault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
335{
336 unsigned int index;
337 pgd_t *pgd, *pgd_k;
338 pmd_t *pmd, *pmd_k;
339
340 if (addr < TASK_SIZE)
341 return do_pf(addr, fsr, regs);
342
343 if (user_mode(regs))
344 goto bad_area;
345
346 index = pgd_index(addr);
347
348 pgd = cpu_get_pgd() + index;
349 pgd_k = init_mm.pgd + index;
350
351 if (pgd_none(*pgd_k))
352 goto bad_area;
353
354 pmd_k = pmd_offset((pud_t *) pgd_k, addr);
355 pmd = pmd_offset((pud_t *) pgd, addr);
356
357 if (pmd_none(*pmd_k))
358 goto bad_area;
359
360 set_pmd(pmd, *pmd_k);
361 flush_pmd_entry(pmd);
362 return 0;
363
364bad_area:
365 do_bad_area(addr, fsr, regs);
366 return 0;
367}
368
369
370
371
372static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
373{
374 return 1;
375}
376
377static int do_good(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
378{
379 unsigned int res1, res2;
380
381 printk("dabt exception but no error!\n");
382
383 __asm__ __volatile__(
384 "mff %0,f0\n"
385 "mff %1,f1\n"
386 : "=r"(res1), "=r"(res2)
387 :
388 : "memory");
389
390 printk(KERN_EMERG "r0 :%08x r1 :%08x\n", res1, res2);
391 panic("shut up\n");
392 return 0;
393}
394
395static struct fsr_info {
396 int (*fn) (unsigned long addr, unsigned int fsr, struct pt_regs *regs);
397 int sig;
398 int code;
399 const char *name;
400} fsr_info[] = {
401
402
403
404 { do_good, SIGBUS, 0, "no error" },
405 { do_bad, SIGBUS, BUS_ADRALN, "alignment exception" },
406 { do_bad, SIGBUS, BUS_OBJERR, "external exception" },
407 { do_bad, SIGBUS, 0, "burst operation" },
408 { do_bad, SIGBUS, 0, "unknown 00100" },
409 { do_ifault, SIGSEGV, SEGV_MAPERR, "2nd level pt non-exist"},
410 { do_bad, SIGBUS, 0, "2nd lvl large pt non-exist" },
411 { do_bad, SIGBUS, 0, "invalid pte" },
412 { do_pf, SIGSEGV, SEGV_MAPERR, "page miss" },
413 { do_bad, SIGBUS, 0, "middle page miss" },
414 { do_bad, SIGBUS, 0, "large page miss" },
415 { do_pf, SIGSEGV, SEGV_MAPERR, "super page (section) miss" },
416 { do_bad, SIGBUS, 0, "unknown 01100" },
417 { do_bad, SIGBUS, 0, "unknown 01101" },
418 { do_bad, SIGBUS, 0, "unknown 01110" },
419 { do_bad, SIGBUS, 0, "unknown 01111" },
420 { do_bad, SIGBUS, 0, "addr: up 3G or IO" },
421 { do_pf, SIGSEGV, SEGV_ACCERR, "read unreadable addr" },
422 { do_pf, SIGSEGV, SEGV_ACCERR, "write unwriteable addr"},
423 { do_pf, SIGSEGV, SEGV_ACCERR, "exec unexecutable addr"},
424 { do_bad, SIGBUS, 0, "unknown 10100" },
425 { do_bad, SIGBUS, 0, "unknown 10101" },
426 { do_bad, SIGBUS, 0, "unknown 10110" },
427 { do_bad, SIGBUS, 0, "unknown 10111" },
428 { do_bad, SIGBUS, 0, "unknown 11000" },
429 { do_bad, SIGBUS, 0, "unknown 11001" },
430 { do_bad, SIGBUS, 0, "unknown 11010" },
431 { do_bad, SIGBUS, 0, "unknown 11011" },
432 { do_bad, SIGBUS, 0, "unknown 11100" },
433 { do_bad, SIGBUS, 0, "unknown 11101" },
434 { do_bad, SIGBUS, 0, "unknown 11110" },
435 { do_bad, SIGBUS, 0, "unknown 11111" }
436};
437
438void __init hook_fault_code(int nr,
439 int (*fn) (unsigned long, unsigned int, struct pt_regs *),
440 int sig, int code, const char *name)
441{
442 if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
443 BUG();
444
445 fsr_info[nr].fn = fn;
446 fsr_info[nr].sig = sig;
447 fsr_info[nr].code = code;
448 fsr_info[nr].name = name;
449}
450
451
452
453
454asmlinkage void do_DataAbort(unsigned long addr, unsigned int fsr,
455 struct pt_regs *regs)
456{
457 const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
458
459 if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
460 return;
461
462 printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
463 inf->name, fsr, addr);
464
465 uc32_notify_die("", regs, inf->sig, inf->code, (void __user *)addr,
466 fsr, 0);
467}
468
469asmlinkage void do_PrefetchAbort(unsigned long addr,
470 unsigned int ifsr, struct pt_regs *regs)
471{
472 const struct fsr_info *inf = fsr_info + fsr_fs(ifsr);
473
474 if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
475 return;
476
477 printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
478 inf->name, ifsr, addr);
479
480 uc32_notify_die("", regs, inf->sig, inf->code, (void __user *)addr,
481 ifsr, 0);
482}
483