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b920de1b DH |
1 | /* MN10300 MMU Fault handler |
2 | * | |
3 | * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd. | |
4 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
5 | * Modified by David Howells (dhowells@redhat.com) | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public Licence | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the Licence, or (at your option) any later version. | |
11 | */ | |
12 | ||
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> | |
22 | #include <linux/smp.h> | |
b920de1b DH |
23 | #include <linux/interrupt.h> |
24 | #include <linux/init.h> | |
25 | #include <linux/vt_kern.h> /* For unblank_screen() */ | |
26 | ||
b920de1b DH |
27 | #include <asm/uaccess.h> |
28 | #include <asm/pgalloc.h> | |
29 | #include <asm/hardirq.h> | |
b920de1b | 30 | #include <asm/cpu-regs.h> |
67ddb405 DH |
31 | #include <asm/debugger.h> |
32 | #include <asm/gdb-stub.h> | |
b920de1b DH |
33 | |
34 | /* | |
35 | * Unlock any spinlocks which will prevent us from getting the | |
36 | * message out | |
37 | */ | |
38 | void bust_spinlocks(int yes) | |
39 | { | |
40 | if (yes) { | |
41 | oops_in_progress = 1; | |
b920de1b DH |
42 | } else { |
43 | int loglevel_save = console_loglevel; | |
44 | #ifdef CONFIG_VT | |
45 | unblank_screen(); | |
46 | #endif | |
47 | oops_in_progress = 0; | |
48 | /* | |
49 | * OK, the message is on the console. Now we call printk() | |
50 | * without oops_in_progress set so that printk will give klogd | |
51 | * a poke. Hold onto your hats... | |
52 | */ | |
53 | console_loglevel = 15; /* NMI oopser may have shut the console | |
54 | * up */ | |
55 | printk(" "); | |
56 | console_loglevel = loglevel_save; | |
57 | } | |
58 | } | |
59 | ||
60 | void do_BUG(const char *file, int line) | |
61 | { | |
62 | bust_spinlocks(1); | |
63 | printk(KERN_EMERG "------------[ cut here ]------------\n"); | |
64 | printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line); | |
65 | } | |
66 | ||
67 | #if 0 | |
68 | static void print_pagetable_entries(pgd_t *pgdir, unsigned long address) | |
69 | { | |
70 | pgd_t *pgd; | |
71 | pmd_t *pmd; | |
72 | pte_t *pte; | |
73 | ||
74 | pgd = pgdir + __pgd_offset(address); | |
75 | printk(KERN_DEBUG "pgd entry %p: %016Lx\n", | |
76 | pgd, (long long) pgd_val(*pgd)); | |
77 | ||
78 | if (!pgd_present(*pgd)) { | |
79 | printk(KERN_DEBUG "... pgd not present!\n"); | |
80 | return; | |
81 | } | |
82 | pmd = pmd_offset(pgd, address); | |
83 | printk(KERN_DEBUG "pmd entry %p: %016Lx\n", | |
84 | pmd, (long long)pmd_val(*pmd)); | |
85 | ||
86 | if (!pmd_present(*pmd)) { | |
87 | printk(KERN_DEBUG "... pmd not present!\n"); | |
88 | return; | |
89 | } | |
90 | pte = pte_offset(pmd, address); | |
91 | printk(KERN_DEBUG "pte entry %p: %016Lx\n", | |
92 | pte, (long long) pte_val(*pte)); | |
93 | ||
94 | if (!pte_present(*pte)) | |
95 | printk(KERN_DEBUG "... pte not present!\n"); | |
96 | } | |
97 | #endif | |
98 | ||
b920de1b DH |
99 | /* |
100 | * This routine handles page faults. It determines the address, | |
101 | * and the problem, and then passes it off to one of the appropriate | |
102 | * routines. | |
103 | * | |
104 | * fault_code: | |
105 | * - LSW: either MMUFCR_IFC or MMUFCR_DFC as appropriate | |
106 | * - MSW: 0 if data access, 1 if instruction access | |
107 | * - bit 0: TLB miss flag | |
108 | * - bit 1: initial write | |
109 | * - bit 2: page invalid | |
110 | * - bit 3: protection violation | |
111 | * - bit 4: accessor (0=user 1=kernel) | |
112 | * - bit 5: 0=read 1=write | |
113 | * - bit 6-8: page protection spec | |
114 | * - bit 9: illegal address | |
115 | * - bit 16: 0=data 1=ins | |
116 | * | |
117 | */ | |
118 | asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code, | |
119 | unsigned long address) | |
120 | { | |
121 | struct vm_area_struct *vma; | |
122 | struct task_struct *tsk; | |
123 | struct mm_struct *mm; | |
124 | unsigned long page; | |
125 | siginfo_t info; | |
3d7b6a67 KC |
126 | int fault; |
127 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; | |
b920de1b DH |
128 | |
129 | #ifdef CONFIG_GDBSTUB | |
130 | /* handle GDB stub causing a fault */ | |
131 | if (gdbstub_busy) { | |
132 | gdbstub_exception(regs, TBR & TBR_INT_CODE); | |
133 | return; | |
134 | } | |
135 | #endif | |
136 | ||
137 | #if 0 | |
138 | printk(KERN_DEBUG "--- do_page_fault(%p,%s:%04lx,%08lx)\n", | |
139 | regs, | |
140 | fault_code & 0x10000 ? "ins" : "data", | |
141 | fault_code & 0xffff, address); | |
142 | #endif | |
143 | ||
144 | tsk = current; | |
145 | ||
146 | /* | |
147 | * We fault-in kernel-space virtual memory on-demand. The | |
148 | * 'reference' page table is init_mm.pgd. | |
149 | * | |
150 | * NOTE! We MUST NOT take any locks for this case. We may | |
151 | * be in an interrupt or a critical region, and should | |
152 | * only copy the information from the master page table, | |
153 | * nothing more. | |
154 | * | |
155 | * This verifies that the fault happens in kernel space | |
156 | * and that the fault was a page not present (invalid) error | |
157 | */ | |
158 | if (address >= VMALLOC_START && address < VMALLOC_END && | |
159 | (fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR && | |
160 | (fault_code & MMUFCR_xFC_PGINVAL) == MMUFCR_xFC_PGINVAL | |
161 | ) | |
162 | goto vmalloc_fault; | |
163 | ||
164 | mm = tsk->mm; | |
165 | info.si_code = SEGV_MAPERR; | |
166 | ||
167 | /* | |
168 | * If we're in an interrupt or have no user | |
169 | * context, we must not take the fault.. | |
170 | */ | |
d1c6d2e5 | 171 | if (in_atomic() || !mm) |
b920de1b DH |
172 | goto no_context; |
173 | ||
3d7b6a67 | 174 | retry: |
b920de1b DH |
175 | down_read(&mm->mmap_sem); |
176 | ||
177 | vma = find_vma(mm, address); | |
178 | if (!vma) | |
179 | goto bad_area; | |
180 | if (vma->vm_start <= address) | |
181 | goto good_area; | |
182 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
183 | goto bad_area; | |
184 | ||
185 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) { | |
186 | /* accessing the stack below the stack pointer is always a | |
187 | * bug */ | |
188 | if ((address & PAGE_MASK) + 2 * PAGE_SIZE < regs->sp) { | |
189 | #if 0 | |
190 | printk(KERN_WARNING | |
191 | "[%d] ### Access below stack @%lx (sp=%lx)\n", | |
192 | current->pid, address, regs->sp); | |
193 | printk(KERN_WARNING | |
194 | "vma [%08x - %08x]\n", | |
195 | vma->vm_start, vma->vm_end); | |
196 | show_registers(regs); | |
197 | printk(KERN_WARNING | |
198 | "[%d] ### Code: [%08lx]" | |
199 | " %02x %02x %02x %02x %02x %02x %02x %02x\n", | |
200 | current->pid, | |
201 | regs->pc, | |
202 | ((u8 *) regs->pc)[0], | |
203 | ((u8 *) regs->pc)[1], | |
204 | ((u8 *) regs->pc)[2], | |
205 | ((u8 *) regs->pc)[3], | |
206 | ((u8 *) regs->pc)[4], | |
207 | ((u8 *) regs->pc)[5], | |
208 | ((u8 *) regs->pc)[6], | |
209 | ((u8 *) regs->pc)[7] | |
210 | ); | |
211 | #endif | |
212 | goto bad_area; | |
213 | } | |
214 | } | |
215 | ||
216 | if (expand_stack(vma, address)) | |
217 | goto bad_area; | |
218 | ||
219 | /* | |
220 | * Ok, we have a good vm_area for this memory access, so | |
221 | * we can handle it.. | |
222 | */ | |
223 | good_area: | |
224 | info.si_code = SEGV_ACCERR; | |
b920de1b DH |
225 | switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) { |
226 | default: /* 3: write, present */ | |
227 | case MMUFCR_xFC_TYPE_WRITE: | |
228 | #ifdef TEST_VERIFY_AREA | |
229 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR) | |
230 | printk(KERN_DEBUG "WP fault at %08lx\n", regs->pc); | |
231 | #endif | |
232 | /* write to absent page */ | |
233 | case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE: | |
234 | if (!(vma->vm_flags & VM_WRITE)) | |
235 | goto bad_area; | |
3d7b6a67 | 236 | flags |= FAULT_FLAG_WRITE; |
b920de1b DH |
237 | break; |
238 | ||
239 | /* read from protected page */ | |
240 | case MMUFCR_xFC_TYPE_READ: | |
241 | goto bad_area; | |
242 | ||
243 | /* read from absent page present */ | |
244 | case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_READ: | |
245 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) | |
246 | goto bad_area; | |
247 | break; | |
248 | } | |
249 | ||
250 | /* | |
251 | * If for any reason at all we couldn't handle the fault, | |
252 | * make sure we exit gracefully rather than endlessly redo | |
253 | * the fault. | |
254 | */ | |
3d7b6a67 KC |
255 | fault = handle_mm_fault(mm, vma, address, flags); |
256 | ||
257 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) | |
258 | return; | |
259 | ||
b920de1b DH |
260 | if (unlikely(fault & VM_FAULT_ERROR)) { |
261 | if (fault & VM_FAULT_OOM) | |
262 | goto out_of_memory; | |
263 | else if (fault & VM_FAULT_SIGBUS) | |
264 | goto do_sigbus; | |
265 | BUG(); | |
266 | } | |
3d7b6a67 KC |
267 | if (flags & FAULT_FLAG_ALLOW_RETRY) { |
268 | if (fault & VM_FAULT_MAJOR) | |
269 | current->maj_flt++; | |
270 | else | |
271 | current->min_flt++; | |
272 | if (fault & VM_FAULT_RETRY) { | |
273 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
274 | ||
275 | /* No need to up_read(&mm->mmap_sem) as we would | |
276 | * have already released it in __lock_page_or_retry | |
277 | * in mm/filemap.c. | |
278 | */ | |
279 | ||
280 | goto retry; | |
281 | } | |
282 | } | |
b920de1b DH |
283 | |
284 | up_read(&mm->mmap_sem); | |
285 | return; | |
286 | ||
287 | /* | |
288 | * Something tried to access memory that isn't in our memory map.. | |
289 | * Fix it, but check if it's kernel or user first.. | |
290 | */ | |
291 | bad_area: | |
292 | up_read(&mm->mmap_sem); | |
b920de1b DH |
293 | |
294 | /* User mode accesses just cause a SIGSEGV */ | |
295 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) { | |
296 | info.si_signo = SIGSEGV; | |
297 | info.si_errno = 0; | |
298 | /* info.si_code has been set above */ | |
299 | info.si_addr = (void *)address; | |
300 | force_sig_info(SIGSEGV, &info, tsk); | |
301 | return; | |
302 | } | |
303 | ||
304 | no_context: | |
b920de1b DH |
305 | /* Are we prepared to handle this kernel fault? */ |
306 | if (fixup_exception(regs)) | |
307 | return; | |
308 | ||
309 | /* | |
310 | * Oops. The kernel tried to access some bad page. We'll have to | |
311 | * terminate things with extreme prejudice. | |
312 | */ | |
313 | ||
314 | bust_spinlocks(1); | |
315 | ||
316 | if (address < PAGE_SIZE) | |
317 | printk(KERN_ALERT | |
318 | "Unable to handle kernel NULL pointer dereference"); | |
319 | else | |
320 | printk(KERN_ALERT | |
321 | "Unable to handle kernel paging request"); | |
322 | printk(" at virtual address %08lx\n", address); | |
323 | printk(" printing pc:\n"); | |
324 | printk(KERN_ALERT "%08lx\n", regs->pc); | |
325 | ||
67ddb405 DH |
326 | debugger_intercept(fault_code & 0x00010000 ? EXCEP_IAERROR : EXCEP_DAERROR, |
327 | SIGSEGV, SEGV_ACCERR, regs); | |
b920de1b DH |
328 | |
329 | page = PTBR; | |
330 | page = ((unsigned long *) __va(page))[address >> 22]; | |
331 | printk(KERN_ALERT "*pde = %08lx\n", page); | |
332 | if (page & 1) { | |
333 | page &= PAGE_MASK; | |
334 | address &= 0x003ff000; | |
335 | page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT]; | |
336 | printk(KERN_ALERT "*pte = %08lx\n", page); | |
337 | } | |
338 | ||
339 | die("Oops", regs, fault_code); | |
340 | do_exit(SIGKILL); | |
341 | ||
342 | /* | |
343 | * We ran out of memory, or some other thing happened to us that made | |
344 | * us unable to handle the page fault gracefully. | |
345 | */ | |
346 | out_of_memory: | |
347 | up_read(&mm->mmap_sem); | |
368dd5ac AT |
348 | printk(KERN_ALERT "VM: killing process %s\n", tsk->comm); |
349 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) | |
350 | do_exit(SIGKILL); | |
351 | goto no_context; | |
b920de1b DH |
352 | |
353 | do_sigbus: | |
354 | up_read(&mm->mmap_sem); | |
b920de1b DH |
355 | |
356 | /* | |
357 | * Send a sigbus, regardless of whether we were in kernel | |
358 | * or user mode. | |
359 | */ | |
360 | info.si_signo = SIGBUS; | |
361 | info.si_errno = 0; | |
362 | info.si_code = BUS_ADRERR; | |
363 | info.si_addr = (void *)address; | |
364 | force_sig_info(SIGBUS, &info, tsk); | |
365 | ||
366 | /* Kernel mode? Handle exceptions or die */ | |
367 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR) | |
368 | goto no_context; | |
369 | return; | |
370 | ||
371 | vmalloc_fault: | |
372 | { | |
373 | /* | |
374 | * Synchronize this task's top level page-table | |
375 | * with the 'reference' page table. | |
376 | * | |
377 | * Do _not_ use "tsk" here. We might be inside | |
378 | * an interrupt in the middle of a task switch.. | |
379 | */ | |
380 | int index = pgd_index(address); | |
381 | pgd_t *pgd, *pgd_k; | |
382 | pud_t *pud, *pud_k; | |
383 | pmd_t *pmd, *pmd_k; | |
384 | pte_t *pte_k; | |
385 | ||
386 | pgd_k = init_mm.pgd + index; | |
387 | ||
388 | if (!pgd_present(*pgd_k)) | |
389 | goto no_context; | |
390 | ||
391 | pud_k = pud_offset(pgd_k, address); | |
392 | if (!pud_present(*pud_k)) | |
393 | goto no_context; | |
394 | ||
395 | pmd_k = pmd_offset(pud_k, address); | |
396 | if (!pmd_present(*pmd_k)) | |
397 | goto no_context; | |
398 | ||
399 | pgd = (pgd_t *) PTBR + index; | |
400 | pud = pud_offset(pgd, address); | |
401 | pmd = pmd_offset(pud, address); | |
402 | set_pmd(pmd, *pmd_k); | |
403 | ||
404 | pte_k = pte_offset_kernel(pmd_k, address); | |
405 | if (!pte_present(*pte_k)) | |
406 | goto no_context; | |
407 | return; | |
408 | } | |
409 | } |