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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> | |
23 | #include <linux/smp_lock.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/vt_kern.h> /* For unblank_screen() */ | |
27 | ||
28 | #include <asm/system.h> | |
29 | #include <asm/uaccess.h> | |
30 | #include <asm/pgalloc.h> | |
31 | #include <asm/hardirq.h> | |
32 | #include <asm/gdb-stub.h> | |
33 | #include <asm/cpu-regs.h> | |
34 | ||
35 | /* | |
36 | * Unlock any spinlocks which will prevent us from getting the | |
37 | * message out | |
38 | */ | |
39 | void bust_spinlocks(int yes) | |
40 | { | |
41 | if (yes) { | |
42 | oops_in_progress = 1; | |
43 | #ifdef CONFIG_SMP | |
44 | /* Many serial drivers do __global_cli() */ | |
45 | global_irq_lock = 0; | |
46 | #endif | |
47 | } else { | |
48 | int loglevel_save = console_loglevel; | |
49 | #ifdef CONFIG_VT | |
50 | unblank_screen(); | |
51 | #endif | |
52 | oops_in_progress = 0; | |
53 | /* | |
54 | * OK, the message is on the console. Now we call printk() | |
55 | * without oops_in_progress set so that printk will give klogd | |
56 | * a poke. Hold onto your hats... | |
57 | */ | |
58 | console_loglevel = 15; /* NMI oopser may have shut the console | |
59 | * up */ | |
60 | printk(" "); | |
61 | console_loglevel = loglevel_save; | |
62 | } | |
63 | } | |
64 | ||
65 | void do_BUG(const char *file, int line) | |
66 | { | |
67 | bust_spinlocks(1); | |
68 | printk(KERN_EMERG "------------[ cut here ]------------\n"); | |
69 | printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line); | |
70 | } | |
71 | ||
72 | #if 0 | |
73 | static void print_pagetable_entries(pgd_t *pgdir, unsigned long address) | |
74 | { | |
75 | pgd_t *pgd; | |
76 | pmd_t *pmd; | |
77 | pte_t *pte; | |
78 | ||
79 | pgd = pgdir + __pgd_offset(address); | |
80 | printk(KERN_DEBUG "pgd entry %p: %016Lx\n", | |
81 | pgd, (long long) pgd_val(*pgd)); | |
82 | ||
83 | if (!pgd_present(*pgd)) { | |
84 | printk(KERN_DEBUG "... pgd not present!\n"); | |
85 | return; | |
86 | } | |
87 | pmd = pmd_offset(pgd, address); | |
88 | printk(KERN_DEBUG "pmd entry %p: %016Lx\n", | |
89 | pmd, (long long)pmd_val(*pmd)); | |
90 | ||
91 | if (!pmd_present(*pmd)) { | |
92 | printk(KERN_DEBUG "... pmd not present!\n"); | |
93 | return; | |
94 | } | |
95 | pte = pte_offset(pmd, address); | |
96 | printk(KERN_DEBUG "pte entry %p: %016Lx\n", | |
97 | pte, (long long) pte_val(*pte)); | |
98 | ||
99 | if (!pte_present(*pte)) | |
100 | printk(KERN_DEBUG "... pte not present!\n"); | |
101 | } | |
102 | #endif | |
103 | ||
104 | asmlinkage void monitor_signal(struct pt_regs *); | |
105 | ||
106 | /* | |
107 | * This routine handles page faults. It determines the address, | |
108 | * and the problem, and then passes it off to one of the appropriate | |
109 | * routines. | |
110 | * | |
111 | * fault_code: | |
112 | * - LSW: either MMUFCR_IFC or MMUFCR_DFC as appropriate | |
113 | * - MSW: 0 if data access, 1 if instruction access | |
114 | * - bit 0: TLB miss flag | |
115 | * - bit 1: initial write | |
116 | * - bit 2: page invalid | |
117 | * - bit 3: protection violation | |
118 | * - bit 4: accessor (0=user 1=kernel) | |
119 | * - bit 5: 0=read 1=write | |
120 | * - bit 6-8: page protection spec | |
121 | * - bit 9: illegal address | |
122 | * - bit 16: 0=data 1=ins | |
123 | * | |
124 | */ | |
125 | asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code, | |
126 | unsigned long address) | |
127 | { | |
128 | struct vm_area_struct *vma; | |
129 | struct task_struct *tsk; | |
130 | struct mm_struct *mm; | |
131 | unsigned long page; | |
132 | siginfo_t info; | |
133 | int write, fault; | |
134 | ||
135 | #ifdef CONFIG_GDBSTUB | |
136 | /* handle GDB stub causing a fault */ | |
137 | if (gdbstub_busy) { | |
138 | gdbstub_exception(regs, TBR & TBR_INT_CODE); | |
139 | return; | |
140 | } | |
141 | #endif | |
142 | ||
143 | #if 0 | |
144 | printk(KERN_DEBUG "--- do_page_fault(%p,%s:%04lx,%08lx)\n", | |
145 | regs, | |
146 | fault_code & 0x10000 ? "ins" : "data", | |
147 | fault_code & 0xffff, address); | |
148 | #endif | |
149 | ||
150 | tsk = current; | |
151 | ||
152 | /* | |
153 | * We fault-in kernel-space virtual memory on-demand. The | |
154 | * 'reference' page table is init_mm.pgd. | |
155 | * | |
156 | * NOTE! We MUST NOT take any locks for this case. We may | |
157 | * be in an interrupt or a critical region, and should | |
158 | * only copy the information from the master page table, | |
159 | * nothing more. | |
160 | * | |
161 | * This verifies that the fault happens in kernel space | |
162 | * and that the fault was a page not present (invalid) error | |
163 | */ | |
164 | if (address >= VMALLOC_START && address < VMALLOC_END && | |
165 | (fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR && | |
166 | (fault_code & MMUFCR_xFC_PGINVAL) == MMUFCR_xFC_PGINVAL | |
167 | ) | |
168 | goto vmalloc_fault; | |
169 | ||
170 | mm = tsk->mm; | |
171 | info.si_code = SEGV_MAPERR; | |
172 | ||
173 | /* | |
174 | * If we're in an interrupt or have no user | |
175 | * context, we must not take the fault.. | |
176 | */ | |
d1c6d2e5 | 177 | if (in_atomic() || !mm) |
b920de1b DH |
178 | goto no_context; |
179 | ||
180 | down_read(&mm->mmap_sem); | |
181 | ||
182 | vma = find_vma(mm, address); | |
183 | if (!vma) | |
184 | goto bad_area; | |
185 | if (vma->vm_start <= address) | |
186 | goto good_area; | |
187 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
188 | goto bad_area; | |
189 | ||
190 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) { | |
191 | /* accessing the stack below the stack pointer is always a | |
192 | * bug */ | |
193 | if ((address & PAGE_MASK) + 2 * PAGE_SIZE < regs->sp) { | |
194 | #if 0 | |
195 | printk(KERN_WARNING | |
196 | "[%d] ### Access below stack @%lx (sp=%lx)\n", | |
197 | current->pid, address, regs->sp); | |
198 | printk(KERN_WARNING | |
199 | "vma [%08x - %08x]\n", | |
200 | vma->vm_start, vma->vm_end); | |
201 | show_registers(regs); | |
202 | printk(KERN_WARNING | |
203 | "[%d] ### Code: [%08lx]" | |
204 | " %02x %02x %02x %02x %02x %02x %02x %02x\n", | |
205 | current->pid, | |
206 | regs->pc, | |
207 | ((u8 *) regs->pc)[0], | |
208 | ((u8 *) regs->pc)[1], | |
209 | ((u8 *) regs->pc)[2], | |
210 | ((u8 *) regs->pc)[3], | |
211 | ((u8 *) regs->pc)[4], | |
212 | ((u8 *) regs->pc)[5], | |
213 | ((u8 *) regs->pc)[6], | |
214 | ((u8 *) regs->pc)[7] | |
215 | ); | |
216 | #endif | |
217 | goto bad_area; | |
218 | } | |
219 | } | |
220 | ||
221 | if (expand_stack(vma, address)) | |
222 | goto bad_area; | |
223 | ||
224 | /* | |
225 | * Ok, we have a good vm_area for this memory access, so | |
226 | * we can handle it.. | |
227 | */ | |
228 | good_area: | |
229 | info.si_code = SEGV_ACCERR; | |
230 | write = 0; | |
231 | switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) { | |
232 | default: /* 3: write, present */ | |
233 | case MMUFCR_xFC_TYPE_WRITE: | |
234 | #ifdef TEST_VERIFY_AREA | |
235 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR) | |
236 | printk(KERN_DEBUG "WP fault at %08lx\n", regs->pc); | |
237 | #endif | |
238 | /* write to absent page */ | |
239 | case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE: | |
240 | if (!(vma->vm_flags & VM_WRITE)) | |
241 | goto bad_area; | |
242 | write++; | |
243 | break; | |
244 | ||
245 | /* read from protected page */ | |
246 | case MMUFCR_xFC_TYPE_READ: | |
247 | goto bad_area; | |
248 | ||
249 | /* read from absent page present */ | |
250 | case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_READ: | |
251 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) | |
252 | goto bad_area; | |
253 | break; | |
254 | } | |
255 | ||
256 | /* | |
257 | * If for any reason at all we couldn't handle the fault, | |
258 | * make sure we exit gracefully rather than endlessly redo | |
259 | * the fault. | |
260 | */ | |
d06063cc | 261 | fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0); |
b920de1b DH |
262 | if (unlikely(fault & VM_FAULT_ERROR)) { |
263 | if (fault & VM_FAULT_OOM) | |
264 | goto out_of_memory; | |
265 | else if (fault & VM_FAULT_SIGBUS) | |
266 | goto do_sigbus; | |
267 | BUG(); | |
268 | } | |
269 | if (fault & VM_FAULT_MAJOR) | |
270 | current->maj_flt++; | |
271 | else | |
272 | current->min_flt++; | |
273 | ||
274 | up_read(&mm->mmap_sem); | |
275 | return; | |
276 | ||
277 | /* | |
278 | * Something tried to access memory that isn't in our memory map.. | |
279 | * Fix it, but check if it's kernel or user first.. | |
280 | */ | |
281 | bad_area: | |
282 | up_read(&mm->mmap_sem); | |
283 | monitor_signal(regs); | |
284 | ||
285 | /* User mode accesses just cause a SIGSEGV */ | |
286 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) { | |
287 | info.si_signo = SIGSEGV; | |
288 | info.si_errno = 0; | |
289 | /* info.si_code has been set above */ | |
290 | info.si_addr = (void *)address; | |
291 | force_sig_info(SIGSEGV, &info, tsk); | |
292 | return; | |
293 | } | |
294 | ||
295 | no_context: | |
296 | monitor_signal(regs); | |
297 | /* Are we prepared to handle this kernel fault? */ | |
298 | if (fixup_exception(regs)) | |
299 | return; | |
300 | ||
301 | /* | |
302 | * Oops. The kernel tried to access some bad page. We'll have to | |
303 | * terminate things with extreme prejudice. | |
304 | */ | |
305 | ||
306 | bust_spinlocks(1); | |
307 | ||
308 | if (address < PAGE_SIZE) | |
309 | printk(KERN_ALERT | |
310 | "Unable to handle kernel NULL pointer dereference"); | |
311 | else | |
312 | printk(KERN_ALERT | |
313 | "Unable to handle kernel paging request"); | |
314 | printk(" at virtual address %08lx\n", address); | |
315 | printk(" printing pc:\n"); | |
316 | printk(KERN_ALERT "%08lx\n", regs->pc); | |
317 | ||
318 | #ifdef CONFIG_GDBSTUB | |
319 | gdbstub_intercept( | |
320 | regs, fault_code & 0x00010000 ? EXCEP_IAERROR : EXCEP_DAERROR); | |
321 | #endif | |
322 | ||
323 | page = PTBR; | |
324 | page = ((unsigned long *) __va(page))[address >> 22]; | |
325 | printk(KERN_ALERT "*pde = %08lx\n", page); | |
326 | if (page & 1) { | |
327 | page &= PAGE_MASK; | |
328 | address &= 0x003ff000; | |
329 | page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT]; | |
330 | printk(KERN_ALERT "*pte = %08lx\n", page); | |
331 | } | |
332 | ||
333 | die("Oops", regs, fault_code); | |
334 | do_exit(SIGKILL); | |
335 | ||
336 | /* | |
337 | * We ran out of memory, or some other thing happened to us that made | |
338 | * us unable to handle the page fault gracefully. | |
339 | */ | |
340 | out_of_memory: | |
341 | up_read(&mm->mmap_sem); | |
342 | monitor_signal(regs); | |
343 | printk(KERN_ALERT "VM: killing process %s\n", tsk->comm); | |
344 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) | |
345 | do_exit(SIGKILL); | |
346 | goto no_context; | |
347 | ||
348 | do_sigbus: | |
349 | up_read(&mm->mmap_sem); | |
350 | monitor_signal(regs); | |
351 | ||
352 | /* | |
353 | * Send a sigbus, regardless of whether we were in kernel | |
354 | * or user mode. | |
355 | */ | |
356 | info.si_signo = SIGBUS; | |
357 | info.si_errno = 0; | |
358 | info.si_code = BUS_ADRERR; | |
359 | info.si_addr = (void *)address; | |
360 | force_sig_info(SIGBUS, &info, tsk); | |
361 | ||
362 | /* Kernel mode? Handle exceptions or die */ | |
363 | if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR) | |
364 | goto no_context; | |
365 | return; | |
366 | ||
367 | vmalloc_fault: | |
368 | { | |
369 | /* | |
370 | * Synchronize this task's top level page-table | |
371 | * with the 'reference' page table. | |
372 | * | |
373 | * Do _not_ use "tsk" here. We might be inside | |
374 | * an interrupt in the middle of a task switch.. | |
375 | */ | |
376 | int index = pgd_index(address); | |
377 | pgd_t *pgd, *pgd_k; | |
378 | pud_t *pud, *pud_k; | |
379 | pmd_t *pmd, *pmd_k; | |
380 | pte_t *pte_k; | |
381 | ||
382 | pgd_k = init_mm.pgd + index; | |
383 | ||
384 | if (!pgd_present(*pgd_k)) | |
385 | goto no_context; | |
386 | ||
387 | pud_k = pud_offset(pgd_k, address); | |
388 | if (!pud_present(*pud_k)) | |
389 | goto no_context; | |
390 | ||
391 | pmd_k = pmd_offset(pud_k, address); | |
392 | if (!pmd_present(*pmd_k)) | |
393 | goto no_context; | |
394 | ||
395 | pgd = (pgd_t *) PTBR + index; | |
396 | pud = pud_offset(pgd, address); | |
397 | pmd = pmd_offset(pud, address); | |
398 | set_pmd(pmd, *pmd_k); | |
399 | ||
400 | pte_k = pte_offset_kernel(pmd_k, address); | |
401 | if (!pte_present(*pte_k)) | |
402 | goto no_context; | |
403 | return; | |
404 | } | |
405 | } |