source: mainline/kernel/arch/mips32/src/mm/tlb.c@ bfce7d9

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since bfce7d9 was bfce7d9, checked in by Jakub Jermar <jakub@…>, 17 years ago

Do not print "Page fault.\n" if a mapping is not found during TLB refill.
  • Property mode set to 100644
File size: 12.7 KB
Line 
1/*
2 * Copyright (c) 2003-2004 Jakub Jermar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup mips32mm
30 * @{
31 */
32/** @file
33 */
34
35#include <arch/mm/tlb.h>
36#include <mm/asid.h>
37#include <mm/tlb.h>
38#include <mm/page.h>
39#include <mm/as.h>
40#include <arch/cp0.h>
41#include <panic.h>
42#include <arch.h>
43#include <symtab.h>
44#include <synch/spinlock.h>
45#include <print.h>
46#include <debug.h>
47#include <align.h>
48#include <interrupt.h>
49
50static void tlb_refill_fail(istate_t *);
51static void tlb_invalid_fail(istate_t *);
52static void tlb_modified_fail(istate_t *);
53
54static pte_t *find_mapping_and_check(uintptr_t, int, istate_t *, int *);
55
56/** Initialize TLB.
57 *
58 * Invalidate all entries and mark wired entries.
59 */
60void tlb_arch_init(void)
61{
62 int i;
63
64 cp0_pagemask_write(TLB_PAGE_MASK_16K);
65 cp0_entry_hi_write(0);
66 cp0_entry_lo0_write(0);
67 cp0_entry_lo1_write(0);
68
69 /* Clear and initialize TLB. */
70
71 for (i = 0; i < TLB_ENTRY_COUNT; i++) {
72 cp0_index_write(i);
73 tlbwi();
74 }
75
76 /*
77 * The kernel is going to make use of some wired
78 * entries (e.g. mapping kernel stacks in kseg3).
79 */
80 cp0_wired_write(TLB_WIRED);
81}
82
83/** Process TLB Refill Exception.
84 *
85 * @param istate Interrupted register context.
86 */
87void tlb_refill(istate_t *istate)
88{
89 entry_lo_t lo;
90 entry_hi_t hi;
91 asid_t asid;
92 uintptr_t badvaddr;
93 pte_t *pte;
94 int pfrc;
95
96 badvaddr = cp0_badvaddr_read();
97
98 spinlock_lock(&AS->lock);
99 asid = AS->asid;
100 spinlock_unlock(&AS->lock);
101
102 page_table_lock(AS, true);
103
104 pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate, &pfrc);
105 if (!pte) {
106 switch (pfrc) {
107 case AS_PF_FAULT:
108 goto fail;
109 break;
110 case AS_PF_DEFER:
111 /*
112 * The page fault came during copy_from_uspace()
113 * or copy_to_uspace().
114 */
115 page_table_unlock(AS, true);
116 return;
117 default:
118 panic("unexpected pfrc (%d)\n", pfrc);
119 }
120 }
121
122 /*
123 * Record access to PTE.
124 */
125 pte->a = 1;
126
127 tlb_prepare_entry_hi(&hi, asid, badvaddr);
128 tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->cacheable,
129 pte->pfn);
130
131 /*
132 * New entry is to be inserted into TLB
133 */
134 cp0_entry_hi_write(hi.value);
135 if ((badvaddr / PAGE_SIZE) % 2 == 0) {
136 cp0_entry_lo0_write(lo.value);
137 cp0_entry_lo1_write(0);
138 }
139 else {
140 cp0_entry_lo0_write(0);
141 cp0_entry_lo1_write(lo.value);
142 }
143 cp0_pagemask_write(TLB_PAGE_MASK_16K);
144 tlbwr();
145
146 page_table_unlock(AS, true);
147 return;
148
149fail:
150 page_table_unlock(AS, true);
151 tlb_refill_fail(istate);
152}
153
154/** Process TLB Invalid Exception.
155 *
156 * @param istate Interrupted register context.
157 */
158void tlb_invalid(istate_t *istate)
159{
160 tlb_index_t index;
161 uintptr_t badvaddr;
162 entry_lo_t lo;
163 entry_hi_t hi;
164 pte_t *pte;
165 int pfrc;
166
167 badvaddr = cp0_badvaddr_read();
168
169 /*
170 * Locate the faulting entry in TLB.
171 */
172 hi.value = cp0_entry_hi_read();
173 tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
174 cp0_entry_hi_write(hi.value);
175 tlbp();
176 index.value = cp0_index_read();
177
178 page_table_lock(AS, true);
179
180 /*
181 * Fail if the entry is not in TLB.
182 */
183 if (index.p) {
184 printf("TLB entry not found.\n");
185 goto fail;
186 }
187
188 pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate, &pfrc);
189 if (!pte) {
190 switch (pfrc) {
191 case AS_PF_FAULT:
192 goto fail;
193 break;
194 case AS_PF_DEFER:
195 /*
196 * The page fault came during copy_from_uspace()
197 * or copy_to_uspace().
198 */
199 page_table_unlock(AS, true);
200 return;
201 default:
202 panic("unexpected pfrc (%d)\n", pfrc);
203 }
204 }
205
206 /*
207 * Read the faulting TLB entry.
208 */
209 tlbr();
210
211 /*
212 * Record access to PTE.
213 */
214 pte->a = 1;
215
216 tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->cacheable,
217 pte->pfn);
218
219 /*
220 * The entry is to be updated in TLB.
221 */
222 if ((badvaddr / PAGE_SIZE) % 2 == 0)
223 cp0_entry_lo0_write(lo.value);
224 else
225 cp0_entry_lo1_write(lo.value);
226 cp0_pagemask_write(TLB_PAGE_MASK_16K);
227 tlbwi();
228
229 page_table_unlock(AS, true);
230 return;
231
232fail:
233 page_table_unlock(AS, true);
234 tlb_invalid_fail(istate);
235}
236
237/** Process TLB Modified Exception.
238 *
239 * @param istate Interrupted register context.
240 */
241void tlb_modified(istate_t *istate)
242{
243 tlb_index_t index;
244 uintptr_t badvaddr;
245 entry_lo_t lo;
246 entry_hi_t hi;
247 pte_t *pte;
248 int pfrc;
249
250 badvaddr = cp0_badvaddr_read();
251
252 /*
253 * Locate the faulting entry in TLB.
254 */
255 hi.value = cp0_entry_hi_read();
256 tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
257 cp0_entry_hi_write(hi.value);
258 tlbp();
259 index.value = cp0_index_read();
260
261 page_table_lock(AS, true);
262
263 /*
264 * Fail if the entry is not in TLB.
265 */
266 if (index.p) {
267 printf("TLB entry not found.\n");
268 goto fail;
269 }
270
271 pte = find_mapping_and_check(badvaddr, PF_ACCESS_WRITE, istate, &pfrc);
272 if (!pte) {
273 switch (pfrc) {
274 case AS_PF_FAULT:
275 goto fail;
276 break;
277 case AS_PF_DEFER:
278 /*
279 * The page fault came during copy_from_uspace()
280 * or copy_to_uspace().
281 */
282 page_table_unlock(AS, true);
283 return;
284 default:
285 panic("unexpected pfrc (%d)\n", pfrc);
286 }
287 }
288
289 /*
290 * Read the faulting TLB entry.
291 */
292 tlbr();
293
294 /*
295 * Record access and write to PTE.
296 */
297 pte->a = 1;
298 pte->d = 1;
299
300 tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->w, pte->cacheable,
301 pte->pfn);
302
303 /*
304 * The entry is to be updated in TLB.
305 */
306 if ((badvaddr / PAGE_SIZE) % 2 == 0)
307 cp0_entry_lo0_write(lo.value);
308 else
309 cp0_entry_lo1_write(lo.value);
310 cp0_pagemask_write(TLB_PAGE_MASK_16K);
311 tlbwi();
312
313 page_table_unlock(AS, true);
314 return;
315
316fail:
317 page_table_unlock(AS, true);
318 tlb_modified_fail(istate);
319}
320
321void tlb_refill_fail(istate_t *istate)
322{
323 char *symbol = "";
324 char *sym2 = "";
325
326 char *s = get_symtab_entry(istate->epc);
327 if (s)
328 symbol = s;
329 s = get_symtab_entry(istate->ra);
330 if (s)
331 sym2 = s;
332
333 fault_if_from_uspace(istate, "TLB Refill Exception on %p",
334 cp0_badvaddr_read());
335 panic("%x: TLB Refill Exception at %x(%s<-%s)\n", cp0_badvaddr_read(),
336 istate->epc, symbol, sym2);
337}
338
339
340void tlb_invalid_fail(istate_t *istate)
341{
342 char *symbol = "";
343
344 char *s = get_symtab_entry(istate->epc);
345 if (s)
346 symbol = s;
347 fault_if_from_uspace(istate, "TLB Invalid Exception on %p",
348 cp0_badvaddr_read());
349 panic("%x: TLB Invalid Exception at %x(%s)\n", cp0_badvaddr_read(),
350 istate->epc, symbol);
351}
352
353void tlb_modified_fail(istate_t *istate)
354{
355 char *symbol = "";
356
357 char *s = get_symtab_entry(istate->epc);
358 if (s)
359 symbol = s;
360 fault_if_from_uspace(istate, "TLB Modified Exception on %p",
361 cp0_badvaddr_read());
362 panic("%x: TLB Modified Exception at %x(%s)\n", cp0_badvaddr_read(),
363 istate->epc, symbol);
364}
365
366/** Try to find PTE for faulting address.
367 *
368 * The AS->lock must be held on entry to this function.
369 *
370 * @param badvaddr Faulting virtual address.
371 * @param access Access mode that caused the fault.
372 * @param istate Pointer to interrupted state.
373 * @param pfrc Pointer to variable where as_page_fault() return code
374 * will be stored.
375 *
376 * @return PTE on success, NULL otherwise.
377 */
378pte_t *
379find_mapping_and_check(uintptr_t badvaddr, int access, istate_t *istate,
380 int *pfrc)
381{
382 entry_hi_t hi;
383 pte_t *pte;
384
385 hi.value = cp0_entry_hi_read();
386
387 /*
388 * Handler cannot succeed if the ASIDs don't match.
389 */
390 if (hi.asid != AS->asid) {
391 printf("EntryHi.asid=%d, AS->asid=%d\n", hi.asid, AS->asid);
392 return NULL;
393 }
394
395 /*
396 * Check if the mapping exists in page tables.
397 */
398 pte = page_mapping_find(AS, badvaddr);
399 if (pte && pte->p && (pte->w || access != PF_ACCESS_WRITE)) {
400 /*
401 * Mapping found in page tables.
402 * Immediately succeed.
403 */
404 return pte;
405 } else {
406 int rc;
407
408 /*
409 * Mapping not found in page tables.
410 * Resort to higher-level page fault handler.
411 */
412 page_table_unlock(AS, true);
413 switch (rc = as_page_fault(badvaddr, access, istate)) {
414 case AS_PF_OK:
415 /*
416 * The higher-level page fault handler succeeded,
417 * The mapping ought to be in place.
418 */
419 page_table_lock(AS, true);
420 pte = page_mapping_find(AS, badvaddr);
421 ASSERT(pte && pte->p);
422 ASSERT(pte->w || access != PF_ACCESS_WRITE);
423 return pte;
424 break;
425 case AS_PF_DEFER:
426 page_table_lock(AS, true);
427 *pfrc = AS_PF_DEFER;
428 return NULL;
429 break;
430 case AS_PF_FAULT:
431 page_table_lock(AS, true);
432 *pfrc = AS_PF_FAULT;
433 return NULL;
434 break;
435 default:
436 panic("unexpected rc (%d)\n", rc);
437 }
438
439 }
440}
441
442void
443tlb_prepare_entry_lo(entry_lo_t *lo, bool g, bool v, bool d, bool cacheable,
444 uintptr_t pfn)
445{
446 lo->value = 0;
447 lo->g = g;
448 lo->v = v;
449 lo->d = d;
450 lo->c = cacheable ? PAGE_CACHEABLE_EXC_WRITE : PAGE_UNCACHED;
451 lo->pfn = pfn;
452}
453
454void tlb_prepare_entry_hi(entry_hi_t *hi, asid_t asid, uintptr_t addr)
455{
456 hi->value = ALIGN_DOWN(addr, PAGE_SIZE * 2);
457 hi->asid = asid;
458}
459
460/** Print contents of TLB. */
461void tlb_print(void)
462{
463 page_mask_t mask;
464 entry_lo_t lo0, lo1;
465 entry_hi_t hi, hi_save;
466 unsigned int i;
467
468 hi_save.value = cp0_entry_hi_read();
469
470 printf("# ASID VPN2 MASK G V D C PFN\n");
471 printf("-- ---- ------ ---- - - - - ------\n");
472
473 for (i = 0; i < TLB_ENTRY_COUNT; i++) {
474 cp0_index_write(i);
475 tlbr();
476
477 mask.value = cp0_pagemask_read();
478 hi.value = cp0_entry_hi_read();
479 lo0.value = cp0_entry_lo0_read();
480 lo1.value = cp0_entry_lo1_read();
481
482 printf("%-2u %-4u %#6x %#4x %1u %1u %1u %1u %#6x\n",
483 i, hi.asid, hi.vpn2, mask.mask,
484 lo0.g, lo0.v, lo0.d, lo0.c, lo0.pfn);
485 printf(" %1u %1u %1u %1u %#6x\n",
486 lo1.g, lo1.v, lo1.d, lo1.c, lo1.pfn);
487 }
488
489 cp0_entry_hi_write(hi_save.value);
490}
491
492/** Invalidate all not wired TLB entries. */
493void tlb_invalidate_all(void)
494{
495 ipl_t ipl;
496 entry_lo_t lo0, lo1;
497 entry_hi_t hi_save;
498 int i;
499
500 hi_save.value = cp0_entry_hi_read();
501 ipl = interrupts_disable();
502
503 for (i = TLB_WIRED; i < TLB_ENTRY_COUNT; i++) {
504 cp0_index_write(i);
505 tlbr();
506
507 lo0.value = cp0_entry_lo0_read();
508 lo1.value = cp0_entry_lo1_read();
509
510 lo0.v = 0;
511 lo1.v = 0;
512
513 cp0_entry_lo0_write(lo0.value);
514 cp0_entry_lo1_write(lo1.value);
515
516 tlbwi();
517 }
518
519 interrupts_restore(ipl);
520 cp0_entry_hi_write(hi_save.value);
521}
522
523/** Invalidate all TLB entries belonging to specified address space.
524 *
525 * @param asid Address space identifier.
526 */
527void tlb_invalidate_asid(asid_t asid)
528{
529 ipl_t ipl;
530 entry_lo_t lo0, lo1;
531 entry_hi_t hi, hi_save;
532 int i;
533
534 ASSERT(asid != ASID_INVALID);
535
536 hi_save.value = cp0_entry_hi_read();
537 ipl = interrupts_disable();
538
539 for (i = 0; i < TLB_ENTRY_COUNT; i++) {
540 cp0_index_write(i);
541 tlbr();
542
543 hi.value = cp0_entry_hi_read();
544
545 if (hi.asid == asid) {
546 lo0.value = cp0_entry_lo0_read();
547 lo1.value = cp0_entry_lo1_read();
548
549 lo0.v = 0;
550 lo1.v = 0;
551
552 cp0_entry_lo0_write(lo0.value);
553 cp0_entry_lo1_write(lo1.value);
554
555 tlbwi();
556 }
557 }
558
559 interrupts_restore(ipl);
560 cp0_entry_hi_write(hi_save.value);
561}
562
563/** Invalidate TLB entries for specified page range belonging to specified
564 * address space.
565 *
566 * @param asid Address space identifier.
567 * @param page First page whose TLB entry is to be invalidated.
568 * @param cnt Number of entries to invalidate.
569 */
570void tlb_invalidate_pages(asid_t asid, uintptr_t page, count_t cnt)
571{
572 unsigned int i;
573 ipl_t ipl;
574 entry_lo_t lo0, lo1;
575 entry_hi_t hi, hi_save;
576 tlb_index_t index;
577
578 ASSERT(asid != ASID_INVALID);
579
580 hi_save.value = cp0_entry_hi_read();
581 ipl = interrupts_disable();
582
583 for (i = 0; i < cnt + 1; i += 2) {
584 hi.value = 0;
585 tlb_prepare_entry_hi(&hi, asid, page + i * PAGE_SIZE);
586 cp0_entry_hi_write(hi.value);
587
588 tlbp();
589 index.value = cp0_index_read();
590
591 if (!index.p) {
592 /*
593 * Entry was found, index register contains valid
594 * index.
595 */
596 tlbr();
597
598 lo0.value = cp0_entry_lo0_read();
599 lo1.value = cp0_entry_lo1_read();
600
601 lo0.v = 0;
602 lo1.v = 0;
603
604 cp0_entry_lo0_write(lo0.value);
605 cp0_entry_lo1_write(lo1.value);
606
607 tlbwi();
608 }
609 }
610
611 interrupts_restore(ipl);
612 cp0_entry_hi_write(hi_save.value);
613}
614
615/** @}
616 */
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