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1da177e4 LT |
1 | /* |
2 | * linux/arch/m32r/mm/fault.c | |
3 | * | |
4 | * Copyright (c) 2001, 2002 Hitoshi Yamamoto, and H. Kondo | |
5 | * Copyright (c) 2004 Naoto Sugai, NIIBE Yutaka | |
6 | * | |
7 | * Some code taken from i386 version. | |
8 | * Copyright (C) 1995 Linus Torvalds | |
9 | */ | |
10 | ||
11 | #include <linux/config.h> | |
12 | #include <linux/signal.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/string.h> | |
17 | #include <linux/types.h> | |
18 | #include <linux/ptrace.h> | |
19 | #include <linux/mman.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/smp.h> | |
22 | #include <linux/smp_lock.h> | |
23 | #include <linux/interrupt.h> | |
24 | #include <linux/init.h> | |
25 | #include <linux/tty.h> | |
26 | #include <linux/vt_kern.h> /* For unblank_screen() */ | |
27 | #include <linux/highmem.h> | |
28 | #include <linux/module.h> | |
29 | ||
30 | #include <asm/m32r.h> | |
31 | #include <asm/system.h> | |
32 | #include <asm/uaccess.h> | |
33 | #include <asm/hardirq.h> | |
34 | #include <asm/mmu_context.h> | |
35 | #include <asm/tlbflush.h> | |
36 | ||
37 | extern void die(const char *, struct pt_regs *, long); | |
38 | ||
39 | #ifndef CONFIG_SMP | |
40 | asmlinkage unsigned int tlb_entry_i_dat; | |
41 | asmlinkage unsigned int tlb_entry_d_dat; | |
42 | #define tlb_entry_i tlb_entry_i_dat | |
43 | #define tlb_entry_d tlb_entry_d_dat | |
44 | #else | |
45 | unsigned int tlb_entry_i_dat[NR_CPUS]; | |
46 | unsigned int tlb_entry_d_dat[NR_CPUS]; | |
47 | #define tlb_entry_i tlb_entry_i_dat[smp_processor_id()] | |
48 | #define tlb_entry_d tlb_entry_d_dat[smp_processor_id()] | |
49 | #endif | |
50 | ||
51 | extern void init_tlb(void); | |
52 | ||
53 | /* | |
54 | * Unlock any spinlocks which will prevent us from getting the | |
55 | * message out | |
56 | */ | |
57 | void bust_spinlocks(int yes) | |
58 | { | |
59 | int loglevel_save = console_loglevel; | |
60 | ||
61 | if (yes) { | |
62 | oops_in_progress = 1; | |
63 | return; | |
64 | } | |
65 | #ifdef CONFIG_VT | |
66 | unblank_screen(); | |
67 | #endif | |
68 | oops_in_progress = 0; | |
69 | /* | |
70 | * OK, the message is on the console. Now we call printk() | |
71 | * without oops_in_progress set so that printk will give klogd | |
72 | * a poke. Hold onto your hats... | |
73 | */ | |
74 | console_loglevel = 15; /* NMI oopser may have shut the console up */ | |
75 | printk(" "); | |
76 | console_loglevel = loglevel_save; | |
77 | } | |
78 | ||
79 | /*======================================================================* | |
80 | * do_page_fault() | |
81 | *======================================================================* | |
82 | * This routine handles page faults. It determines the address, | |
83 | * and the problem, and then passes it off to one of the appropriate | |
84 | * routines. | |
85 | * | |
86 | * ARGUMENT: | |
87 | * regs : M32R SP reg. | |
88 | * error_code : See below | |
89 | * address : M32R MMU MDEVA reg. (Operand ACE) | |
90 | * : M32R BPC reg. (Instruction ACE) | |
91 | * | |
92 | * error_code : | |
93 | * bit 0 == 0 means no page found, 1 means protection fault | |
94 | * bit 1 == 0 means read, 1 means write | |
95 | * bit 2 == 0 means kernel, 1 means user-mode | |
96 | * bit 3 == 0 means data, 1 means instruction | |
97 | *======================================================================*/ | |
98 | #define ACE_PROTECTION 1 | |
99 | #define ACE_WRITE 2 | |
100 | #define ACE_USERMODE 4 | |
101 | #define ACE_INSTRUCTION 8 | |
102 | ||
103 | asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, | |
104 | unsigned long address) | |
105 | { | |
106 | struct task_struct *tsk; | |
107 | struct mm_struct *mm; | |
108 | struct vm_area_struct * vma; | |
109 | unsigned long page, addr; | |
110 | int write; | |
111 | siginfo_t info; | |
112 | ||
113 | /* | |
114 | * If BPSW IE bit enable --> set PSW IE bit | |
115 | */ | |
116 | if (regs->psw & M32R_PSW_BIE) | |
117 | local_irq_enable(); | |
118 | ||
119 | tsk = current; | |
120 | ||
121 | info.si_code = SEGV_MAPERR; | |
122 | ||
123 | /* | |
124 | * We fault-in kernel-space virtual memory on-demand. The | |
125 | * 'reference' page table is init_mm.pgd. | |
126 | * | |
127 | * NOTE! We MUST NOT take any locks for this case. We may | |
128 | * be in an interrupt or a critical region, and should | |
129 | * only copy the information from the master page table, | |
130 | * nothing more. | |
131 | * | |
132 | * This verifies that the fault happens in kernel space | |
133 | * (error_code & ACE_USERMODE) == 0, and that the fault was not a | |
134 | * protection error (error_code & ACE_PROTECTION) == 0. | |
135 | */ | |
136 | if (address >= TASK_SIZE && !(error_code & ACE_USERMODE)) | |
137 | goto vmalloc_fault; | |
138 | ||
139 | mm = tsk->mm; | |
140 | ||
141 | /* | |
142 | * If we're in an interrupt or have no user context or are running in an | |
143 | * atomic region then we must not take the fault.. | |
144 | */ | |
145 | if (in_atomic() || !mm) | |
146 | goto bad_area_nosemaphore; | |
147 | ||
148 | /* When running in the kernel we expect faults to occur only to | |
149 | * addresses in user space. All other faults represent errors in the | |
150 | * kernel and should generate an OOPS. Unfortunatly, in the case of an | |
151 | * erroneous fault occuring in a code path which already holds mmap_sem | |
152 | * we will deadlock attempting to validate the fault against the | |
153 | * address space. Luckily the kernel only validly references user | |
154 | * space from well defined areas of code, which are listed in the | |
155 | * exceptions table. | |
156 | * | |
157 | * As the vast majority of faults will be valid we will only perform | |
158 | * the source reference check when there is a possibilty of a deadlock. | |
159 | * Attempt to lock the address space, if we cannot we then validate the | |
160 | * source. If this is invalid we can skip the address space check, | |
161 | * thus avoiding the deadlock. | |
162 | */ | |
163 | if (!down_read_trylock(&mm->mmap_sem)) { | |
164 | if ((error_code & ACE_USERMODE) == 0 && | |
165 | !search_exception_tables(regs->psw)) | |
166 | goto bad_area_nosemaphore; | |
167 | down_read(&mm->mmap_sem); | |
168 | } | |
169 | ||
170 | vma = find_vma(mm, address); | |
171 | if (!vma) | |
172 | goto bad_area; | |
173 | if (vma->vm_start <= address) | |
174 | goto good_area; | |
175 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
176 | goto bad_area; | |
177 | #if 0 | |
178 | if (error_code & ACE_USERMODE) { | |
179 | /* | |
180 | * accessing the stack below "spu" is always a bug. | |
181 | * The "+ 4" is there due to the push instruction | |
182 | * doing pre-decrement on the stack and that | |
183 | * doesn't show up until later.. | |
184 | */ | |
185 | if (address + 4 < regs->spu) | |
186 | goto bad_area; | |
187 | } | |
188 | #endif | |
189 | if (expand_stack(vma, address)) | |
190 | goto bad_area; | |
191 | /* | |
192 | * Ok, we have a good vm_area for this memory access, so | |
193 | * we can handle it.. | |
194 | */ | |
195 | good_area: | |
196 | info.si_code = SEGV_ACCERR; | |
197 | write = 0; | |
198 | switch (error_code & (ACE_WRITE|ACE_PROTECTION)) { | |
199 | default: /* 3: write, present */ | |
200 | /* fall through */ | |
201 | case ACE_WRITE: /* write, not present */ | |
202 | if (!(vma->vm_flags & VM_WRITE)) | |
203 | goto bad_area; | |
204 | write++; | |
205 | break; | |
206 | case ACE_PROTECTION: /* read, present */ | |
207 | case 0: /* read, not present */ | |
208 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) | |
209 | goto bad_area; | |
210 | } | |
211 | ||
212 | /* | |
213 | * For instruction access exception, check if the area is executable | |
214 | */ | |
215 | if ((error_code & ACE_INSTRUCTION) && !(vma->vm_flags & VM_EXEC)) | |
216 | goto bad_area; | |
217 | ||
218 | survive: | |
219 | /* | |
220 | * If for any reason at all we couldn't handle the fault, | |
221 | * make sure we exit gracefully rather than endlessly redo | |
222 | * the fault. | |
223 | */ | |
224 | addr = (address & PAGE_MASK); | |
225 | set_thread_fault_code(error_code); | |
226 | switch (handle_mm_fault(mm, vma, addr, write)) { | |
227 | case VM_FAULT_MINOR: | |
228 | tsk->min_flt++; | |
229 | break; | |
230 | case VM_FAULT_MAJOR: | |
231 | tsk->maj_flt++; | |
232 | break; | |
233 | case VM_FAULT_SIGBUS: | |
234 | goto do_sigbus; | |
235 | case VM_FAULT_OOM: | |
236 | goto out_of_memory; | |
237 | default: | |
238 | BUG(); | |
239 | } | |
240 | set_thread_fault_code(0); | |
241 | up_read(&mm->mmap_sem); | |
242 | return; | |
243 | ||
244 | /* | |
245 | * Something tried to access memory that isn't in our memory map.. | |
246 | * Fix it, but check if it's kernel or user first.. | |
247 | */ | |
248 | bad_area: | |
249 | up_read(&mm->mmap_sem); | |
250 | ||
251 | bad_area_nosemaphore: | |
252 | /* User mode accesses just cause a SIGSEGV */ | |
253 | if (error_code & ACE_USERMODE) { | |
254 | tsk->thread.address = address; | |
255 | tsk->thread.error_code = error_code | (address >= TASK_SIZE); | |
256 | tsk->thread.trap_no = 14; | |
257 | info.si_signo = SIGSEGV; | |
258 | info.si_errno = 0; | |
259 | /* info.si_code has been set above */ | |
260 | info.si_addr = (void __user *)address; | |
261 | force_sig_info(SIGSEGV, &info, tsk); | |
262 | return; | |
263 | } | |
264 | ||
265 | no_context: | |
266 | /* Are we prepared to handle this kernel fault? */ | |
267 | if (fixup_exception(regs)) | |
268 | return; | |
269 | ||
270 | /* | |
271 | * Oops. The kernel tried to access some bad page. We'll have to | |
272 | * terminate things with extreme prejudice. | |
273 | */ | |
274 | ||
275 | bust_spinlocks(1); | |
276 | ||
277 | if (address < PAGE_SIZE) | |
278 | printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); | |
279 | else | |
280 | printk(KERN_ALERT "Unable to handle kernel paging request"); | |
281 | printk(" at virtual address %08lx\n",address); | |
282 | printk(KERN_ALERT " printing bpc:\n"); | |
283 | printk("%08lx\n", regs->bpc); | |
284 | page = *(unsigned long *)MPTB; | |
285 | page = ((unsigned long *) page)[address >> PGDIR_SHIFT]; | |
286 | printk(KERN_ALERT "*pde = %08lx\n", page); | |
287 | if (page & _PAGE_PRESENT) { | |
288 | page &= PAGE_MASK; | |
289 | address &= 0x003ff000; | |
290 | page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT]; | |
291 | printk(KERN_ALERT "*pte = %08lx\n", page); | |
292 | } | |
293 | die("Oops", regs, error_code); | |
294 | bust_spinlocks(0); | |
295 | do_exit(SIGKILL); | |
296 | ||
297 | /* | |
298 | * We ran out of memory, or some other thing happened to us that made | |
299 | * us unable to handle the page fault gracefully. | |
300 | */ | |
301 | out_of_memory: | |
302 | up_read(&mm->mmap_sem); | |
303 | if (tsk->pid == 1) { | |
304 | yield(); | |
305 | down_read(&mm->mmap_sem); | |
306 | goto survive; | |
307 | } | |
308 | printk("VM: killing process %s\n", tsk->comm); | |
309 | if (error_code & ACE_USERMODE) | |
310 | do_exit(SIGKILL); | |
311 | goto no_context; | |
312 | ||
313 | do_sigbus: | |
314 | up_read(&mm->mmap_sem); | |
315 | ||
316 | /* Kernel mode? Handle exception or die */ | |
317 | if (!(error_code & ACE_USERMODE)) | |
318 | goto no_context; | |
319 | ||
320 | tsk->thread.address = address; | |
321 | tsk->thread.error_code = error_code; | |
322 | tsk->thread.trap_no = 14; | |
323 | info.si_signo = SIGBUS; | |
324 | info.si_errno = 0; | |
325 | info.si_code = BUS_ADRERR; | |
326 | info.si_addr = (void __user *)address; | |
327 | force_sig_info(SIGBUS, &info, tsk); | |
328 | return; | |
329 | ||
330 | vmalloc_fault: | |
331 | { | |
332 | /* | |
333 | * Synchronize this task's top level page-table | |
334 | * with the 'reference' page table. | |
335 | * | |
336 | * Do _not_ use "tsk" here. We might be inside | |
337 | * an interrupt in the middle of a task switch.. | |
338 | */ | |
339 | int offset = pgd_index(address); | |
340 | pgd_t *pgd, *pgd_k; | |
341 | pmd_t *pmd, *pmd_k; | |
342 | pte_t *pte_k; | |
343 | ||
344 | pgd = (pgd_t *)*(unsigned long *)MPTB; | |
345 | pgd = offset + (pgd_t *)pgd; | |
346 | pgd_k = init_mm.pgd + offset; | |
347 | ||
348 | if (!pgd_present(*pgd_k)) | |
349 | goto no_context; | |
350 | ||
351 | /* | |
352 | * set_pgd(pgd, *pgd_k); here would be useless on PAE | |
353 | * and redundant with the set_pmd() on non-PAE. | |
354 | */ | |
355 | ||
356 | pmd = pmd_offset(pgd, address); | |
357 | pmd_k = pmd_offset(pgd_k, address); | |
358 | if (!pmd_present(*pmd_k)) | |
359 | goto no_context; | |
360 | set_pmd(pmd, *pmd_k); | |
361 | ||
362 | pte_k = pte_offset_kernel(pmd_k, address); | |
363 | if (!pte_present(*pte_k)) | |
364 | goto no_context; | |
365 | ||
366 | addr = (address & PAGE_MASK) | (error_code & ACE_INSTRUCTION); | |
367 | update_mmu_cache(NULL, addr, *pte_k); | |
368 | return; | |
369 | } | |
370 | } | |
371 | ||
372 | /*======================================================================* | |
373 | * update_mmu_cache() | |
374 | *======================================================================*/ | |
375 | #define TLB_MASK (NR_TLB_ENTRIES - 1) | |
376 | #define ITLB_END (unsigned long *)(ITLB_BASE + (NR_TLB_ENTRIES * 8)) | |
377 | #define DTLB_END (unsigned long *)(DTLB_BASE + (NR_TLB_ENTRIES * 8)) | |
378 | void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr, | |
379 | pte_t pte) | |
380 | { | |
381 | unsigned long *entry1, *entry2; | |
382 | unsigned long pte_data, flags; | |
383 | unsigned int *entry_dat; | |
384 | int inst = get_thread_fault_code() & ACE_INSTRUCTION; | |
385 | int i; | |
386 | ||
387 | /* Ptrace may call this routine. */ | |
388 | if (vma && current->active_mm != vma->vm_mm) | |
389 | return; | |
390 | ||
391 | local_irq_save(flags); | |
392 | ||
393 | vaddr = (vaddr & PAGE_MASK) | get_asid(); | |
394 | ||
395 | #ifdef CONFIG_CHIP_OPSP | |
396 | entry1 = (unsigned long *)ITLB_BASE; | |
397 | for(i = 0 ; i < NR_TLB_ENTRIES; i++) { | |
398 | if(*entry1++ == vaddr) { | |
399 | pte_data = pte_val(pte); | |
400 | set_tlb_data(entry1, pte_data); | |
401 | break; | |
402 | } | |
403 | entry1++; | |
404 | } | |
405 | entry2 = (unsigned long *)DTLB_BASE; | |
406 | for(i = 0 ; i < NR_TLB_ENTRIES ; i++) { | |
407 | if(*entry2++ == vaddr) { | |
408 | pte_data = pte_val(pte); | |
409 | set_tlb_data(entry2, pte_data); | |
410 | break; | |
411 | } | |
412 | entry2++; | |
413 | } | |
414 | local_irq_restore(flags); | |
415 | return; | |
416 | #else | |
417 | pte_data = pte_val(pte); | |
418 | ||
419 | /* | |
420 | * Update TLB entries | |
421 | * entry1: ITLB entry address | |
422 | * entry2: DTLB entry address | |
423 | */ | |
424 | __asm__ __volatile__ ( | |
425 | "seth %0, #high(%4) \n\t" | |
426 | "st %2, @(%5, %0) \n\t" | |
427 | "ldi %1, #1 \n\t" | |
428 | "st %1, @(%6, %0) \n\t" | |
429 | "add3 r4, %0, %7 \n\t" | |
430 | ".fillinsn \n" | |
431 | "1: \n\t" | |
432 | "ld %1, @(%6, %0) \n\t" | |
433 | "bnez %1, 1b \n\t" | |
434 | "ld %0, @r4+ \n\t" | |
435 | "ld %1, @r4 \n\t" | |
436 | "st %3, @+%0 \n\t" | |
437 | "st %3, @+%1 \n\t" | |
438 | : "=&r" (entry1), "=&r" (entry2) | |
439 | : "r" (vaddr), "r" (pte_data), "i" (MMU_REG_BASE), | |
440 | "i" (MSVA_offset), "i" (MTOP_offset), "i" (MIDXI_offset) | |
441 | : "r4", "memory" | |
442 | ); | |
443 | ||
444 | if ((!inst && entry2 >= DTLB_END) || (inst && entry1 >= ITLB_END)) | |
445 | goto notfound; | |
446 | ||
447 | found: | |
448 | local_irq_restore(flags); | |
449 | ||
450 | return; | |
451 | ||
452 | /* Valid entry not found */ | |
453 | notfound: | |
454 | /* | |
455 | * Update ITLB or DTLB entry | |
456 | * entry1: TLB entry address | |
457 | * entry2: TLB base address | |
458 | */ | |
459 | if (!inst) { | |
460 | entry2 = (unsigned long *)DTLB_BASE; | |
461 | entry_dat = &tlb_entry_d; | |
462 | } else { | |
463 | entry2 = (unsigned long *)ITLB_BASE; | |
464 | entry_dat = &tlb_entry_i; | |
465 | } | |
466 | entry1 = entry2 + (((*entry_dat - 1) & TLB_MASK) << 1); | |
467 | ||
468 | for (i = 0 ; i < NR_TLB_ENTRIES ; i++) { | |
469 | if (!(entry1[1] & 2)) /* Valid bit check */ | |
470 | break; | |
471 | ||
472 | if (entry1 != entry2) | |
473 | entry1 -= 2; | |
474 | else | |
475 | entry1 += TLB_MASK << 1; | |
476 | } | |
477 | ||
478 | if (i >= NR_TLB_ENTRIES) { /* Empty entry not found */ | |
479 | entry1 = entry2 + (*entry_dat << 1); | |
480 | *entry_dat = (*entry_dat + 1) & TLB_MASK; | |
481 | } | |
482 | *entry1++ = vaddr; /* Set TLB tag */ | |
483 | set_tlb_data(entry1, pte_data); | |
484 | ||
485 | goto found; | |
486 | #endif | |
487 | } | |
488 | ||
489 | /*======================================================================* | |
490 | * flush_tlb_page() : flushes one page | |
491 | *======================================================================*/ | |
492 | void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page) | |
493 | { | |
494 | if (vma->vm_mm && mm_context(vma->vm_mm) != NO_CONTEXT) { | |
495 | unsigned long flags; | |
496 | ||
497 | local_irq_save(flags); | |
498 | page &= PAGE_MASK; | |
499 | page |= (mm_context(vma->vm_mm) & MMU_CONTEXT_ASID_MASK); | |
500 | __flush_tlb_page(page); | |
501 | local_irq_restore(flags); | |
502 | } | |
503 | } | |
504 | ||
505 | /*======================================================================* | |
506 | * flush_tlb_range() : flushes a range of pages | |
507 | *======================================================================*/ | |
508 | void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start, | |
509 | unsigned long end) | |
510 | { | |
511 | struct mm_struct *mm; | |
512 | ||
513 | mm = vma->vm_mm; | |
514 | if (mm_context(mm) != NO_CONTEXT) { | |
515 | unsigned long flags; | |
516 | int size; | |
517 | ||
518 | local_irq_save(flags); | |
519 | size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT; | |
520 | if (size > (NR_TLB_ENTRIES / 4)) { /* Too many TLB to flush */ | |
521 | mm_context(mm) = NO_CONTEXT; | |
522 | if (mm == current->mm) | |
523 | activate_context(mm); | |
524 | } else { | |
525 | unsigned long asid; | |
526 | ||
527 | asid = mm_context(mm) & MMU_CONTEXT_ASID_MASK; | |
528 | start &= PAGE_MASK; | |
529 | end += (PAGE_SIZE - 1); | |
530 | end &= PAGE_MASK; | |
531 | ||
532 | start |= asid; | |
533 | end |= asid; | |
534 | while (start < end) { | |
535 | __flush_tlb_page(start); | |
536 | start += PAGE_SIZE; | |
537 | } | |
538 | } | |
539 | local_irq_restore(flags); | |
540 | } | |
541 | } | |
542 | ||
543 | /*======================================================================* | |
544 | * flush_tlb_mm() : flushes the specified mm context TLB's | |
545 | *======================================================================*/ | |
546 | void local_flush_tlb_mm(struct mm_struct *mm) | |
547 | { | |
548 | /* Invalidate all TLB of this process. */ | |
549 | /* Instead of invalidating each TLB, we get new MMU context. */ | |
550 | if (mm_context(mm) != NO_CONTEXT) { | |
551 | unsigned long flags; | |
552 | ||
553 | local_irq_save(flags); | |
554 | mm_context(mm) = NO_CONTEXT; | |
555 | if (mm == current->mm) | |
556 | activate_context(mm); | |
557 | local_irq_restore(flags); | |
558 | } | |
559 | } | |
560 | ||
561 | /*======================================================================* | |
562 | * flush_tlb_all() : flushes all processes TLBs | |
563 | *======================================================================*/ | |
564 | void local_flush_tlb_all(void) | |
565 | { | |
566 | unsigned long flags; | |
567 | ||
568 | local_irq_save(flags); | |
569 | __flush_tlb_all(); | |
570 | local_irq_restore(flags); | |
571 | } | |
572 | ||
573 | /*======================================================================* | |
574 | * init_mmu() | |
575 | *======================================================================*/ | |
576 | void __init init_mmu(void) | |
577 | { | |
578 | tlb_entry_i = 0; | |
579 | tlb_entry_d = 0; | |
580 | mmu_context_cache = MMU_CONTEXT_FIRST_VERSION; | |
581 | set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK); | |
582 | *(volatile unsigned long *)MPTB = (unsigned long)swapper_pg_dir; | |
583 | } |