Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/mm/fault.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | * Modifications for ARM processor (c) 1995-2004 Russell King | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
1da177e4 LT |
11 | #include <linux/module.h> |
12 | #include <linux/signal.h> | |
1da177e4 LT |
13 | #include <linux/mm.h> |
14 | #include <linux/init.h> | |
15 | ||
16 | #include <asm/system.h> | |
17 | #include <asm/pgtable.h> | |
18 | #include <asm/tlbflush.h> | |
19 | #include <asm/uaccess.h> | |
20 | ||
21 | #include "fault.h" | |
22 | ||
23 | /* | |
24 | * This is useful to dump out the page tables associated with | |
25 | * 'addr' in mm 'mm'. | |
26 | */ | |
27 | void show_pte(struct mm_struct *mm, unsigned long addr) | |
28 | { | |
29 | pgd_t *pgd; | |
30 | ||
31 | if (!mm) | |
32 | mm = &init_mm; | |
33 | ||
34 | printk(KERN_ALERT "pgd = %p\n", mm->pgd); | |
35 | pgd = pgd_offset(mm, addr); | |
36 | printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd)); | |
37 | ||
38 | do { | |
39 | pmd_t *pmd; | |
40 | pte_t *pte; | |
41 | ||
42 | if (pgd_none(*pgd)) | |
43 | break; | |
44 | ||
45 | if (pgd_bad(*pgd)) { | |
46 | printk("(bad)"); | |
47 | break; | |
48 | } | |
49 | ||
50 | pmd = pmd_offset(pgd, addr); | |
51 | #if PTRS_PER_PMD != 1 | |
52 | printk(", *pmd=%08lx", pmd_val(*pmd)); | |
53 | #endif | |
54 | ||
55 | if (pmd_none(*pmd)) | |
56 | break; | |
57 | ||
58 | if (pmd_bad(*pmd)) { | |
59 | printk("(bad)"); | |
60 | break; | |
61 | } | |
62 | ||
63 | #ifndef CONFIG_HIGHMEM | |
64 | /* We must not map this if we have highmem enabled */ | |
65 | pte = pte_offset_map(pmd, addr); | |
66 | printk(", *pte=%08lx", pte_val(*pte)); | |
67 | printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE])); | |
68 | pte_unmap(pte); | |
69 | #endif | |
70 | } while(0); | |
71 | ||
72 | printk("\n"); | |
73 | } | |
74 | ||
75 | /* | |
76 | * Oops. The kernel tried to access some page that wasn't present. | |
77 | */ | |
78 | static void | |
79 | __do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr, | |
80 | struct pt_regs *regs) | |
81 | { | |
82 | /* | |
83 | * Are we prepared to handle this kernel fault? | |
84 | */ | |
85 | if (fixup_exception(regs)) | |
86 | return; | |
87 | ||
88 | /* | |
89 | * No handler, we'll have to terminate things with extreme prejudice. | |
90 | */ | |
91 | bust_spinlocks(1); | |
92 | printk(KERN_ALERT | |
93 | "Unable to handle kernel %s at virtual address %08lx\n", | |
94 | (addr < PAGE_SIZE) ? "NULL pointer dereference" : | |
95 | "paging request", addr); | |
96 | ||
97 | show_pte(mm, addr); | |
98 | die("Oops", regs, fsr); | |
99 | bust_spinlocks(0); | |
100 | do_exit(SIGKILL); | |
101 | } | |
102 | ||
103 | /* | |
104 | * Something tried to access memory that isn't in our memory map.. | |
105 | * User mode accesses just cause a SIGSEGV | |
106 | */ | |
107 | static void | |
108 | __do_user_fault(struct task_struct *tsk, unsigned long addr, | |
2d137c24 | 109 | unsigned int fsr, unsigned int sig, int code, |
110 | struct pt_regs *regs) | |
1da177e4 LT |
111 | { |
112 | struct siginfo si; | |
113 | ||
114 | #ifdef CONFIG_DEBUG_USER | |
115 | if (user_debug & UDBG_SEGV) { | |
2d137c24 | 116 | printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n", |
117 | tsk->comm, sig, addr, fsr); | |
1da177e4 LT |
118 | show_pte(tsk->mm, addr); |
119 | show_regs(regs); | |
120 | } | |
121 | #endif | |
122 | ||
123 | tsk->thread.address = addr; | |
124 | tsk->thread.error_code = fsr; | |
125 | tsk->thread.trap_no = 14; | |
2d137c24 | 126 | si.si_signo = sig; |
1da177e4 LT |
127 | si.si_errno = 0; |
128 | si.si_code = code; | |
129 | si.si_addr = (void __user *)addr; | |
2d137c24 | 130 | force_sig_info(sig, &si, tsk); |
1da177e4 LT |
131 | } |
132 | ||
e5beac37 | 133 | void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs) |
1da177e4 | 134 | { |
e5beac37 RK |
135 | struct task_struct *tsk = current; |
136 | struct mm_struct *mm = tsk->active_mm; | |
137 | ||
1da177e4 LT |
138 | /* |
139 | * If we are in kernel mode at this point, we | |
140 | * have no context to handle this fault with. | |
141 | */ | |
142 | if (user_mode(regs)) | |
2d137c24 | 143 | __do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs); |
1da177e4 LT |
144 | else |
145 | __do_kernel_fault(mm, addr, fsr, regs); | |
146 | } | |
147 | ||
5c72fc5c NP |
148 | #define VM_FAULT_BADMAP 0x010000 |
149 | #define VM_FAULT_BADACCESS 0x020000 | |
1da177e4 LT |
150 | |
151 | static int | |
152 | __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr, | |
153 | struct task_struct *tsk) | |
154 | { | |
155 | struct vm_area_struct *vma; | |
156 | int fault, mask; | |
157 | ||
158 | vma = find_vma(mm, addr); | |
159 | fault = VM_FAULT_BADMAP; | |
160 | if (!vma) | |
161 | goto out; | |
162 | if (vma->vm_start > addr) | |
163 | goto check_stack; | |
164 | ||
165 | /* | |
166 | * Ok, we have a good vm_area for this | |
167 | * memory access, so we can handle it. | |
168 | */ | |
169 | good_area: | |
170 | if (fsr & (1 << 11)) /* write? */ | |
171 | mask = VM_WRITE; | |
172 | else | |
df67b3da | 173 | mask = VM_READ|VM_EXEC|VM_WRITE; |
1da177e4 LT |
174 | |
175 | fault = VM_FAULT_BADACCESS; | |
176 | if (!(vma->vm_flags & mask)) | |
177 | goto out; | |
178 | ||
179 | /* | |
180 | * If for any reason at all we couldn't handle | |
181 | * the fault, make sure we exit gracefully rather | |
182 | * than endlessly redo the fault. | |
183 | */ | |
184 | survive: | |
185 | fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11)); | |
83c54070 NP |
186 | if (unlikely(fault & VM_FAULT_ERROR)) { |
187 | if (fault & VM_FAULT_OOM) | |
188 | goto out_of_memory; | |
189 | else if (fault & VM_FAULT_SIGBUS) | |
190 | return fault; | |
191 | BUG(); | |
192 | } | |
193 | if (fault & VM_FAULT_MAJOR) | |
1da177e4 | 194 | tsk->maj_flt++; |
83c54070 | 195 | else |
1da177e4 | 196 | tsk->min_flt++; |
83c54070 | 197 | return fault; |
1da177e4 | 198 | |
83c54070 | 199 | out_of_memory: |
b460cbc5 | 200 | if (!is_global_init(tsk)) |
1da177e4 LT |
201 | goto out; |
202 | ||
203 | /* | |
2d137c24 | 204 | * If we are out of memory for pid1, sleep for a while and retry |
1da177e4 | 205 | */ |
2d137c24 | 206 | up_read(&mm->mmap_sem); |
1da177e4 | 207 | yield(); |
2d137c24 | 208 | down_read(&mm->mmap_sem); |
1da177e4 LT |
209 | goto survive; |
210 | ||
211 | check_stack: | |
212 | if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) | |
213 | goto good_area; | |
214 | out: | |
215 | return fault; | |
216 | } | |
217 | ||
218 | static int | |
219 | do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) | |
220 | { | |
221 | struct task_struct *tsk; | |
222 | struct mm_struct *mm; | |
2d137c24 | 223 | int fault, sig, code; |
1da177e4 LT |
224 | |
225 | tsk = current; | |
226 | mm = tsk->mm; | |
227 | ||
228 | /* | |
229 | * If we're in an interrupt or have no user | |
230 | * context, we must not take the fault.. | |
231 | */ | |
6edaf68a | 232 | if (in_atomic() || !mm) |
1da177e4 LT |
233 | goto no_context; |
234 | ||
840ff6a4 RK |
235 | /* |
236 | * As per x86, we may deadlock here. However, since the kernel only | |
237 | * validly references user space from well defined areas of the code, | |
238 | * we can bug out early if this is from code which shouldn't. | |
239 | */ | |
240 | if (!down_read_trylock(&mm->mmap_sem)) { | |
241 | if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc)) | |
242 | goto no_context; | |
243 | down_read(&mm->mmap_sem); | |
244 | } | |
245 | ||
1da177e4 LT |
246 | fault = __do_page_fault(mm, addr, fsr, tsk); |
247 | up_read(&mm->mmap_sem); | |
248 | ||
249 | /* | |
ff2afb9d | 250 | * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR |
1da177e4 | 251 | */ |
5c72fc5c | 252 | if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS)))) |
1da177e4 LT |
253 | return 0; |
254 | ||
1da177e4 LT |
255 | /* |
256 | * If we are in kernel mode at this point, we | |
257 | * have no context to handle this fault with. | |
258 | */ | |
259 | if (!user_mode(regs)) | |
260 | goto no_context; | |
261 | ||
83c54070 | 262 | if (fault & VM_FAULT_OOM) { |
1da177e4 | 263 | /* |
2d137c24 | 264 | * We ran out of memory, or some other thing |
265 | * happened to us that made us unable to handle | |
266 | * the page fault gracefully. | |
1da177e4 LT |
267 | */ |
268 | printk("VM: killing process %s\n", tsk->comm); | |
dcca2bde | 269 | do_group_exit(SIGKILL); |
2d137c24 | 270 | return 0; |
83c54070 NP |
271 | } |
272 | if (fault & VM_FAULT_SIGBUS) { | |
2d137c24 | 273 | /* |
274 | * We had some memory, but were unable to | |
275 | * successfully fix up this page fault. | |
276 | */ | |
277 | sig = SIGBUS; | |
278 | code = BUS_ADRERR; | |
83c54070 | 279 | } else { |
2d137c24 | 280 | /* |
281 | * Something tried to access memory that | |
282 | * isn't in our memory map.. | |
283 | */ | |
284 | sig = SIGSEGV; | |
285 | code = fault == VM_FAULT_BADACCESS ? | |
286 | SEGV_ACCERR : SEGV_MAPERR; | |
1da177e4 | 287 | } |
1da177e4 | 288 | |
2d137c24 | 289 | __do_user_fault(tsk, addr, fsr, sig, code, regs); |
290 | return 0; | |
1da177e4 LT |
291 | |
292 | no_context: | |
293 | __do_kernel_fault(mm, addr, fsr, regs); | |
294 | return 0; | |
295 | } | |
296 | ||
297 | /* | |
298 | * First Level Translation Fault Handler | |
299 | * | |
300 | * We enter here because the first level page table doesn't contain | |
301 | * a valid entry for the address. | |
302 | * | |
303 | * If the address is in kernel space (>= TASK_SIZE), then we are | |
304 | * probably faulting in the vmalloc() area. | |
305 | * | |
306 | * If the init_task's first level page tables contains the relevant | |
307 | * entry, we copy the it to this task. If not, we send the process | |
308 | * a signal, fixup the exception, or oops the kernel. | |
309 | * | |
310 | * NOTE! We MUST NOT take any locks for this case. We may be in an | |
311 | * interrupt or a critical region, and should only copy the information | |
312 | * from the master page table, nothing more. | |
313 | */ | |
314 | static int | |
315 | do_translation_fault(unsigned long addr, unsigned int fsr, | |
316 | struct pt_regs *regs) | |
317 | { | |
1da177e4 LT |
318 | unsigned int index; |
319 | pgd_t *pgd, *pgd_k; | |
320 | pmd_t *pmd, *pmd_k; | |
321 | ||
322 | if (addr < TASK_SIZE) | |
323 | return do_page_fault(addr, fsr, regs); | |
324 | ||
325 | index = pgd_index(addr); | |
326 | ||
327 | /* | |
328 | * FIXME: CP15 C1 is write only on ARMv3 architectures. | |
329 | */ | |
330 | pgd = cpu_get_pgd() + index; | |
331 | pgd_k = init_mm.pgd + index; | |
332 | ||
333 | if (pgd_none(*pgd_k)) | |
334 | goto bad_area; | |
335 | ||
336 | if (!pgd_present(*pgd)) | |
337 | set_pgd(pgd, *pgd_k); | |
338 | ||
339 | pmd_k = pmd_offset(pgd_k, addr); | |
340 | pmd = pmd_offset(pgd, addr); | |
341 | ||
342 | if (pmd_none(*pmd_k)) | |
343 | goto bad_area; | |
344 | ||
345 | copy_pmd(pmd, pmd_k); | |
346 | return 0; | |
347 | ||
348 | bad_area: | |
e5beac37 | 349 | do_bad_area(addr, fsr, regs); |
1da177e4 LT |
350 | return 0; |
351 | } | |
352 | ||
353 | /* | |
354 | * Some section permission faults need to be handled gracefully. | |
355 | * They can happen due to a __{get,put}_user during an oops. | |
356 | */ | |
357 | static int | |
358 | do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) | |
359 | { | |
e5beac37 | 360 | do_bad_area(addr, fsr, regs); |
1da177e4 LT |
361 | return 0; |
362 | } | |
363 | ||
364 | /* | |
365 | * This abort handler always returns "fault". | |
366 | */ | |
367 | static int | |
368 | do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs) | |
369 | { | |
370 | return 1; | |
371 | } | |
372 | ||
373 | static struct fsr_info { | |
374 | int (*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs); | |
375 | int sig; | |
cfb0810e | 376 | int code; |
1da177e4 LT |
377 | const char *name; |
378 | } fsr_info[] = { | |
379 | /* | |
380 | * The following are the standard ARMv3 and ARMv4 aborts. ARMv5 | |
381 | * defines these to be "precise" aborts. | |
382 | */ | |
cfb0810e RK |
383 | { do_bad, SIGSEGV, 0, "vector exception" }, |
384 | { do_bad, SIGILL, BUS_ADRALN, "alignment exception" }, | |
385 | { do_bad, SIGKILL, 0, "terminal exception" }, | |
386 | { do_bad, SIGILL, BUS_ADRALN, "alignment exception" }, | |
387 | { do_bad, SIGBUS, 0, "external abort on linefetch" }, | |
388 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" }, | |
389 | { do_bad, SIGBUS, 0, "external abort on linefetch" }, | |
390 | { do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" }, | |
391 | { do_bad, SIGBUS, 0, "external abort on non-linefetch" }, | |
392 | { do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" }, | |
393 | { do_bad, SIGBUS, 0, "external abort on non-linefetch" }, | |
394 | { do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" }, | |
395 | { do_bad, SIGBUS, 0, "external abort on translation" }, | |
396 | { do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" }, | |
397 | { do_bad, SIGBUS, 0, "external abort on translation" }, | |
398 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" }, | |
1da177e4 LT |
399 | /* |
400 | * The following are "imprecise" aborts, which are signalled by bit | |
401 | * 10 of the FSR, and may not be recoverable. These are only | |
402 | * supported if the CPU abort handler supports bit 10. | |
403 | */ | |
cfb0810e RK |
404 | { do_bad, SIGBUS, 0, "unknown 16" }, |
405 | { do_bad, SIGBUS, 0, "unknown 17" }, | |
406 | { do_bad, SIGBUS, 0, "unknown 18" }, | |
407 | { do_bad, SIGBUS, 0, "unknown 19" }, | |
408 | { do_bad, SIGBUS, 0, "lock abort" }, /* xscale */ | |
409 | { do_bad, SIGBUS, 0, "unknown 21" }, | |
410 | { do_bad, SIGBUS, BUS_OBJERR, "imprecise external abort" }, /* xscale */ | |
411 | { do_bad, SIGBUS, 0, "unknown 23" }, | |
412 | { do_bad, SIGBUS, 0, "dcache parity error" }, /* xscale */ | |
413 | { do_bad, SIGBUS, 0, "unknown 25" }, | |
414 | { do_bad, SIGBUS, 0, "unknown 26" }, | |
415 | { do_bad, SIGBUS, 0, "unknown 27" }, | |
416 | { do_bad, SIGBUS, 0, "unknown 28" }, | |
417 | { do_bad, SIGBUS, 0, "unknown 29" }, | |
418 | { do_bad, SIGBUS, 0, "unknown 30" }, | |
419 | { do_bad, SIGBUS, 0, "unknown 31" } | |
1da177e4 LT |
420 | }; |
421 | ||
422 | void __init | |
423 | hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *), | |
424 | int sig, const char *name) | |
425 | { | |
426 | if (nr >= 0 && nr < ARRAY_SIZE(fsr_info)) { | |
427 | fsr_info[nr].fn = fn; | |
428 | fsr_info[nr].sig = sig; | |
429 | fsr_info[nr].name = name; | |
430 | } | |
431 | } | |
432 | ||
433 | /* | |
434 | * Dispatch a data abort to the relevant handler. | |
435 | */ | |
7ab3f8d5 | 436 | asmlinkage void __exception |
1da177e4 LT |
437 | do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs) |
438 | { | |
439 | const struct fsr_info *inf = fsr_info + (fsr & 15) + ((fsr & (1 << 10)) >> 6); | |
cfb0810e | 440 | struct siginfo info; |
1da177e4 LT |
441 | |
442 | if (!inf->fn(addr, fsr, regs)) | |
443 | return; | |
444 | ||
445 | printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n", | |
446 | inf->name, fsr, addr); | |
cfb0810e RK |
447 | |
448 | info.si_signo = inf->sig; | |
449 | info.si_errno = 0; | |
450 | info.si_code = inf->code; | |
451 | info.si_addr = (void __user *)addr; | |
1eeb66a1 | 452 | arm_notify_die("", regs, &info, fsr, 0); |
1da177e4 LT |
453 | } |
454 | ||
7ab3f8d5 | 455 | asmlinkage void __exception |
1da177e4 LT |
456 | do_PrefetchAbort(unsigned long addr, struct pt_regs *regs) |
457 | { | |
458 | do_translation_fault(addr, 0, regs); | |
459 | } | |
460 |