FreeBSD/Linux Kernel Cross Reference
sys/powerpc/aim/slb.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2010 Nathan Whitehorn
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
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 * $FreeBSD$
29 */
30
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/lock.h>
34 #include <sys/malloc.h>
35 #include <sys/mutex.h>
36 #include <sys/proc.h>
37 #include <sys/systm.h>
38
39 #include <vm/vm.h>
40 #include <vm/pmap.h>
41 #include <vm/uma.h>
42 #include <vm/vm.h>
43 #include <vm/vm_map.h>
44 #include <vm/vm_page.h>
45 #include <vm/vm_pageout.h>
46
47 #include <machine/md_var.h>
48 #include <machine/platform.h>
49 #include <machine/vmparam.h>
50 #include <machine/trap.h>
51
52 #include "mmu_oea64.h"
53
54 uintptr_t moea64_get_unique_vsid(void);
55 void moea64_release_vsid(uint64_t vsid);
56 static void slb_zone_init(void *);
57
58 static uma_zone_t slbt_zone;
59 static uma_zone_t slb_cache_zone;
60 int n_slbs = 64;
61
62 SYSINIT(slb_zone_init, SI_SUB_KMEM, SI_ORDER_ANY, slb_zone_init, NULL);
63
64 struct slbtnode {
65 uint16_t ua_alloc;
66 uint8_t ua_level;
67 /* Only 36 bits needed for full 64-bit address space. */
68 uint64_t ua_base;
69 union {
70 struct slbtnode *ua_child[16];
71 struct slb slb_entries[16];
72 } u;
73 };
74
75 /*
76 * For a full 64-bit address space, there are 36 bits in play in an
77 * esid, so 8 levels, with the leaf being at level 0.
78 *
79 * |3333|3322|2222|2222|1111|1111|11 | | | esid
80 * |5432|1098|7654|3210|9876|5432|1098|7654|3210| bits
81 * +----+----+----+----+----+----+----+----+----+--------
82 * | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | level
83 */
84 #define UAD_ROOT_LEVEL 8
85 #define UAD_LEAF_LEVEL 0
86
87 static inline int
88 esid2idx(uint64_t esid, int level)
89 {
90 int shift;
91
92 shift = level * 4;
93 return ((esid >> shift) & 0xF);
94 }
95
96 /*
97 * The ua_base field should have 0 bits after the first 4*(level+1)
98 * bits; i.e. only
99 */
100 #define uad_baseok(ua) \
101 (esid2base(ua->ua_base, ua->ua_level) == ua->ua_base)
102
103 static inline uint64_t
104 esid2base(uint64_t esid, int level)
105 {
106 uint64_t mask;
107 int shift;
108
109 shift = (level + 1) * 4;
110 mask = ~((1ULL << shift) - 1);
111 return (esid & mask);
112 }
113
114 /*
115 * Allocate a new leaf node for the specified esid/vmhandle from the
116 * parent node.
117 */
118 static struct slb *
119 make_new_leaf(uint64_t esid, uint64_t slbv, struct slbtnode *parent)
120 {
121 struct slbtnode *child;
122 struct slb *retval;
123 int idx;
124
125 idx = esid2idx(esid, parent->ua_level);
126 KASSERT(parent->u.ua_child[idx] == NULL, ("Child already exists!"));
127
128 /* unlock and M_WAITOK and loop? */
129 child = uma_zalloc(slbt_zone, M_NOWAIT | M_ZERO);
130 KASSERT(child != NULL, ("unhandled NULL case"));
131
132 child->ua_level = UAD_LEAF_LEVEL;
133 child->ua_base = esid2base(esid, child->ua_level);
134 idx = esid2idx(esid, child->ua_level);
135 child->u.slb_entries[idx].slbv = slbv;
136 child->u.slb_entries[idx].slbe = (esid << SLBE_ESID_SHIFT) | SLBE_VALID;
137 setbit(&child->ua_alloc, idx);
138
139 retval = &child->u.slb_entries[idx];
140
141 /*
142 * The above stores must be visible before the next one, so
143 * that a lockless searcher always sees a valid path through
144 * the tree.
145 */
146 powerpc_lwsync();
147
148 idx = esid2idx(esid, parent->ua_level);
149 parent->u.ua_child[idx] = child;
150 setbit(&parent->ua_alloc, idx);
151
152 return (retval);
153 }
154
155 /*
156 * Allocate a new intermediate node to fit between the parent and
157 * esid.
158 */
159 static struct slbtnode*
160 make_intermediate(uint64_t esid, struct slbtnode *parent)
161 {
162 struct slbtnode *child, *inter;
163 int idx, level;
164
165 idx = esid2idx(esid, parent->ua_level);
166 child = parent->u.ua_child[idx];
167 KASSERT(esid2base(esid, child->ua_level) != child->ua_base,
168 ("No need for an intermediate node?"));
169
170 /*
171 * Find the level where the existing child and our new esid
172 * meet. It must be lower than parent->ua_level or we would
173 * have chosen a different index in parent.
174 */
175 level = child->ua_level + 1;
176 while (esid2base(esid, level) !=
177 esid2base(child->ua_base, level))
178 level++;
179 KASSERT(level < parent->ua_level,
180 ("Found splitting level %d for %09jx and %09jx, "
181 "but it's the same as %p's",
182 level, esid, child->ua_base, parent));
183
184 /* unlock and M_WAITOK and loop? */
185 inter = uma_zalloc(slbt_zone, M_NOWAIT | M_ZERO);
186 KASSERT(inter != NULL, ("unhandled NULL case"));
187
188 /* Set up intermediate node to point to child ... */
189 inter->ua_level = level;
190 inter->ua_base = esid2base(esid, inter->ua_level);
191 idx = esid2idx(child->ua_base, inter->ua_level);
192 inter->u.ua_child[idx] = child;
193 setbit(&inter->ua_alloc, idx);
194 powerpc_lwsync();
195
196 /* Set up parent to point to intermediate node ... */
197 idx = esid2idx(inter->ua_base, parent->ua_level);
198 parent->u.ua_child[idx] = inter;
199 setbit(&parent->ua_alloc, idx);
200
201 return (inter);
202 }
203
204 uint64_t
205 kernel_va_to_slbv(vm_offset_t va)
206 {
207 uint64_t slbv;
208
209 /* Set kernel VSID to deterministic value */
210 slbv = (KERNEL_VSID((uintptr_t)va >> ADDR_SR_SHFT)) << SLBV_VSID_SHIFT;
211
212 /*
213 * Figure out if this is a large-page mapping.
214 */
215 if (hw_direct_map && va > DMAP_BASE_ADDRESS && va < DMAP_MAX_ADDRESS) {
216 /*
217 * XXX: If we have set up a direct map, assumes
218 * all physical memory is mapped with large pages.
219 */
220
221 if (mem_valid(DMAP_TO_PHYS(va), 0) == 0)
222 slbv |= SLBV_L;
223 } else if (moea64_large_page_size != 0 &&
224 va >= (vm_offset_t)vm_page_array &&
225 va <= (uintptr_t)(&vm_page_array[vm_page_array_size]))
226 slbv |= SLBV_L;
227
228 return (slbv);
229 }
230
231 struct slb *
232 user_va_to_slb_entry(pmap_t pm, vm_offset_t va)
233 {
234 uint64_t esid = va >> ADDR_SR_SHFT;
235 struct slbtnode *ua;
236 int idx;
237
238 ua = pm->pm_slb_tree_root;
239
240 for (;;) {
241 KASSERT(uad_baseok(ua), ("uad base %016jx level %d bad!",
242 ua->ua_base, ua->ua_level));
243 idx = esid2idx(esid, ua->ua_level);
244
245 /*
246 * This code is specific to ppc64 where a load is
247 * atomic, so no need for atomic_load macro.
248 */
249 if (ua->ua_level == UAD_LEAF_LEVEL)
250 return ((ua->u.slb_entries[idx].slbe & SLBE_VALID) ?
251 &ua->u.slb_entries[idx] : NULL);
252
253 /*
254 * The following accesses are implicitly ordered under the POWER
255 * ISA by load dependencies (the store ordering is provided by
256 * the powerpc_lwsync() calls elsewhere) and so are run without
257 * barriers.
258 */
259 ua = ua->u.ua_child[idx];
260 if (ua == NULL ||
261 esid2base(esid, ua->ua_level) != ua->ua_base)
262 return (NULL);
263 }
264
265 return (NULL);
266 }
267
268 uint64_t
269 va_to_vsid(pmap_t pm, vm_offset_t va)
270 {
271 struct slb *entry;
272
273 /* Shortcut kernel case */
274 if (pm == kernel_pmap)
275 return (KERNEL_VSID((uintptr_t)va >> ADDR_SR_SHFT));
276
277 /*
278 * If there is no vsid for this VA, we need to add a new entry
279 * to the PMAP's segment table.
280 */
281
282 entry = user_va_to_slb_entry(pm, va);
283
284 if (entry == NULL)
285 return (allocate_user_vsid(pm,
286 (uintptr_t)va >> ADDR_SR_SHFT, 0));
287
288 return ((entry->slbv & SLBV_VSID_MASK) >> SLBV_VSID_SHIFT);
289 }
290
291 uint64_t
292 allocate_user_vsid(pmap_t pm, uint64_t esid, int large)
293 {
294 uint64_t vsid, slbv;
295 struct slbtnode *ua, *next, *inter;
296 struct slb *slb;
297 int idx;
298
299 KASSERT(pm != kernel_pmap, ("Attempting to allocate a kernel VSID"));
300
301 PMAP_LOCK_ASSERT(pm, MA_OWNED);
302 vsid = moea64_get_unique_vsid();
303
304 slbv = vsid << SLBV_VSID_SHIFT;
305 if (large)
306 slbv |= SLBV_L;
307
308 ua = pm->pm_slb_tree_root;
309
310 /* Descend to the correct leaf or NULL pointer. */
311 for (;;) {
312 KASSERT(uad_baseok(ua),
313 ("uad base %09jx level %d bad!", ua->ua_base, ua->ua_level));
314 idx = esid2idx(esid, ua->ua_level);
315
316 if (ua->ua_level == UAD_LEAF_LEVEL) {
317 ua->u.slb_entries[idx].slbv = slbv;
318 eieio();
319 ua->u.slb_entries[idx].slbe = (esid << SLBE_ESID_SHIFT)
320 | SLBE_VALID;
321 setbit(&ua->ua_alloc, idx);
322 slb = &ua->u.slb_entries[idx];
323 break;
324 }
325
326 next = ua->u.ua_child[idx];
327 if (next == NULL) {
328 slb = make_new_leaf(esid, slbv, ua);
329 break;
330 }
331
332 /*
333 * Check if the next item down has an okay ua_base.
334 * If not, we need to allocate an intermediate node.
335 */
336 if (esid2base(esid, next->ua_level) != next->ua_base) {
337 inter = make_intermediate(esid, ua);
338 slb = make_new_leaf(esid, slbv, inter);
339 break;
340 }
341
342 ua = next;
343 }
344
345 /*
346 * Someone probably wants this soon, and it may be a wired
347 * SLB mapping, so pre-spill this entry.
348 */
349 eieio();
350 slb_insert_user(pm, slb);
351
352 return (vsid);
353 }
354
355 void
356 free_vsid(pmap_t pm, uint64_t esid, int large)
357 {
358 struct slbtnode *ua;
359 int idx;
360
361 PMAP_LOCK_ASSERT(pm, MA_OWNED);
362
363 ua = pm->pm_slb_tree_root;
364 /* Descend to the correct leaf. */
365 for (;;) {
366 KASSERT(uad_baseok(ua),
367 ("uad base %09jx level %d bad!", ua->ua_base, ua->ua_level));
368
369 idx = esid2idx(esid, ua->ua_level);
370 if (ua->ua_level == UAD_LEAF_LEVEL) {
371 ua->u.slb_entries[idx].slbv = 0;
372 eieio();
373 ua->u.slb_entries[idx].slbe = 0;
374 clrbit(&ua->ua_alloc, idx);
375 return;
376 }
377
378 ua = ua->u.ua_child[idx];
379 if (ua == NULL ||
380 esid2base(esid, ua->ua_level) != ua->ua_base) {
381 /* Perhaps just return instead of assert? */
382 KASSERT(0,
383 ("Asked to remove an entry that was never inserted!"));
384 return;
385 }
386 }
387 }
388
389 static void
390 free_slb_tree_node(struct slbtnode *ua)
391 {
392 int idx;
393
394 for (idx = 0; idx < 16; idx++) {
395 if (ua->ua_level != UAD_LEAF_LEVEL) {
396 if (ua->u.ua_child[idx] != NULL)
397 free_slb_tree_node(ua->u.ua_child[idx]);
398 } else {
399 if (ua->u.slb_entries[idx].slbv != 0)
400 moea64_release_vsid(ua->u.slb_entries[idx].slbv
401 >> SLBV_VSID_SHIFT);
402 }
403 }
404
405 uma_zfree(slbt_zone, ua);
406 }
407
408 void
409 slb_free_tree(pmap_t pm)
410 {
411
412 free_slb_tree_node(pm->pm_slb_tree_root);
413 }
414
415 struct slbtnode *
416 slb_alloc_tree(void)
417 {
418 struct slbtnode *root;
419
420 root = uma_zalloc(slbt_zone, M_NOWAIT | M_ZERO);
421 KASSERT(root != NULL, ("unhandled NULL case"));
422 root->ua_level = UAD_ROOT_LEVEL;
423
424 return (root);
425 }
426
427 /* Lock entries mapping kernel text and stacks */
428
429 void
430 slb_insert_kernel(uint64_t slbe, uint64_t slbv)
431 {
432 struct slb *slbcache;
433 int i;
434
435 /* We don't want to be preempted while modifying the kernel map */
436 critical_enter();
437
438 slbcache = PCPU_GET(aim.slb);
439
440 /* Check for an unused slot, abusing the user slot as a full flag */
441 if (slbcache[USER_SLB_SLOT].slbe == 0) {
442 for (i = 0; i < n_slbs; i++) {
443 if (i == USER_SLB_SLOT)
444 continue;
445 if (!(slbcache[i].slbe & SLBE_VALID))
446 goto fillkernslb;
447 }
448
449 if (i == n_slbs)
450 slbcache[USER_SLB_SLOT].slbe = 1;
451 }
452
453 i = mftb() % n_slbs;
454 if (i == USER_SLB_SLOT)
455 i = (i+1) % n_slbs;
456
457 fillkernslb:
458 KASSERT(i != USER_SLB_SLOT,
459 ("Filling user SLB slot with a kernel mapping"));
460 slbcache[i].slbv = slbv;
461 slbcache[i].slbe = slbe | (uint64_t)i;
462
463 /* If it is for this CPU, put it in the SLB right away */
464 if (pmap_bootstrapped) {
465 /* slbie not required */
466 __asm __volatile ("slbmte %0, %1" ::
467 "r"(slbcache[i].slbv), "r"(slbcache[i].slbe));
468 }
469
470 critical_exit();
471 }
472
473 void
474 slb_insert_user(pmap_t pm, struct slb *slb)
475 {
476 int i;
477
478 PMAP_LOCK_ASSERT(pm, MA_OWNED);
479
480 if (pm->pm_slb_len < n_slbs) {
481 i = pm->pm_slb_len;
482 pm->pm_slb_len++;
483 } else {
484 i = mftb() % n_slbs;
485 }
486
487 /* Note that this replacement is atomic with respect to trap_subr */
488 pm->pm_slb[i] = slb;
489 }
490
491 static void *
492 slb_uma_real_alloc(uma_zone_t zone, vm_size_t bytes, int domain,
493 u_int8_t *flags, int wait)
494 {
495 static vm_offset_t realmax = 0;
496 void *va;
497 vm_page_t m;
498
499 if (realmax == 0)
500 realmax = platform_real_maxaddr();
501
502 *flags = UMA_SLAB_PRIV;
503 m = vm_page_alloc_noobj_contig_domain(domain, malloc2vm_flags(wait) |
504 VM_ALLOC_WIRED, 1, 0, realmax, PAGE_SIZE, PAGE_SIZE,
505 VM_MEMATTR_DEFAULT);
506 if (m == NULL)
507 return (NULL);
508
509 if (hw_direct_map)
510 va = (void *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m));
511 else {
512 va = (void *)(VM_PAGE_TO_PHYS(m) | DMAP_BASE_ADDRESS);
513 pmap_kenter((vm_offset_t)va, VM_PAGE_TO_PHYS(m));
514 }
515
516 return (va);
517 }
518
519 static void
520 slb_zone_init(void *dummy)
521 {
522 slbt_zone = uma_zcreate("SLB tree node", sizeof(struct slbtnode),
523 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
524 UMA_ZONE_CONTIG | UMA_ZONE_VM);
525 slb_cache_zone = uma_zcreate("SLB cache",
526 (n_slbs + 1)*sizeof(struct slb *), NULL, NULL, NULL, NULL,
527 UMA_ALIGN_PTR, UMA_ZONE_CONTIG | UMA_ZONE_VM);
528
529 if (platform_real_maxaddr() != VM_MAX_ADDRESS) {
530 uma_zone_set_allocf(slb_cache_zone, slb_uma_real_alloc);
531 uma_zone_set_allocf(slbt_zone, slb_uma_real_alloc);
532 }
533 }
534
535 struct slb **
536 slb_alloc_user_cache(void)
537 {
538 return (uma_zalloc(slb_cache_zone, M_WAITOK | M_ZERO));
539 }
540
541 void
542 slb_free_user_cache(struct slb **slb)
543 {
544 uma_zfree(slb_cache_zone, slb);
545 }
546
547 /* Handle kernel SLB faults -- runs in real mode, all seat belts off */
548 void
549 handle_kernel_slb_spill(int type, register_t dar, register_t srr0)
550 {
551 struct slb *slbcache;
552 uint64_t slbe, slbv;
553 uint64_t esid, addr;
554 int i;
555
556 addr = (type == EXC_ISE) ? srr0 : dar;
557 slbcache = PCPU_GET(aim.slb);
558 esid = (uintptr_t)addr >> ADDR_SR_SHFT;
559 slbe = (esid << SLBE_ESID_SHIFT) | SLBE_VALID;
560
561 /* See if the hardware flushed this somehow (can happen in LPARs) */
562 for (i = 0; i < n_slbs; i++)
563 if (slbcache[i].slbe == (slbe | (uint64_t)i))
564 return;
565
566 /* Not in the map, needs to actually be added */
567 slbv = kernel_va_to_slbv(addr);
568 if (slbcache[USER_SLB_SLOT].slbe == 0) {
569 for (i = 0; i < n_slbs; i++) {
570 if (i == USER_SLB_SLOT)
571 continue;
572 if (!(slbcache[i].slbe & SLBE_VALID))
573 goto fillkernslb;
574 }
575
576 if (i == n_slbs)
577 slbcache[USER_SLB_SLOT].slbe = 1;
578 }
579
580 /* Sacrifice a random SLB entry that is not the user entry */
581 i = mftb() % n_slbs;
582 if (i == USER_SLB_SLOT)
583 i = (i+1) % n_slbs;
584
585 fillkernslb:
586 /* Write new entry */
587 slbcache[i].slbv = slbv;
588 slbcache[i].slbe = slbe | (uint64_t)i;
589
590 /* Trap handler will restore from cache on exit */
591 }
592
593 int
594 handle_user_slb_spill(pmap_t pm, vm_offset_t addr)
595 {
596 struct slb *user_entry;
597 uint64_t esid;
598 int i;
599
600 if (pm->pm_slb == NULL)
601 return (-1);
602
603 esid = (uintptr_t)addr >> ADDR_SR_SHFT;
604
605 PMAP_LOCK(pm);
606 user_entry = user_va_to_slb_entry(pm, addr);
607
608 if (user_entry == NULL) {
609 /* allocate_vsid auto-spills it */
610 (void)allocate_user_vsid(pm, esid, 0);
611 } else {
612 /*
613 * Check that another CPU has not already mapped this.
614 * XXX: Per-thread SLB caches would be better.
615 */
616 for (i = 0; i < pm->pm_slb_len; i++)
617 if (pm->pm_slb[i] == user_entry)
618 break;
619
620 if (i == pm->pm_slb_len)
621 slb_insert_user(pm, user_entry);
622 }
623 PMAP_UNLOCK(pm);
624
625 return (0);
626 }
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