xref: /freebsd/sys/powerpc/aim/slb.c (revision 7d8f797b725e3efc0a4256554654780df83c456c) 
1 /*-
2  * Copyright (c) 2010 Nathan Whitehorn
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  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. 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  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/lock.h>
32 #include <sys/malloc.h>
33 #include <sys/mutex.h>
34 #include <sys/proc.h>
35 #include <sys/systm.h>
36 
37 #include <vm/vm.h>
38 #include <vm/pmap.h>
39 #include <vm/uma.h>
40 #include <vm/vm.h>
41 #include <vm/vm_map.h>
42 #include <vm/vm_page.h>
43 #include <vm/vm_pageout.h>
44 
45 #include <machine/md_var.h>
46 #include <machine/platform.h>
47 #include <machine/pmap.h>
48 #include <machine/vmparam.h>
49 
50 uintptr_t moea64_get_unique_vsid(void);
51 void moea64_release_vsid(uint64_t vsid);
52 static void slb_zone_init(void *);
53 
54 static uma_zone_t slbt_zone;
55 static uma_zone_t slb_cache_zone;
56 int n_slbs = 64;
57 
58 SYSINIT(slb_zone_init, SI_SUB_KMEM, SI_ORDER_ANY, slb_zone_init, NULL);
59 
60 struct slbtnode {
61 	uint16_t	ua_alloc;
62 	uint8_t		ua_level;
63 	/* Only 36 bits needed for full 64-bit address space. */
64 	uint64_t	ua_base;
65 	union {
66 		struct slbtnode	*ua_child[16];
67 		struct slb	slb_entries[16];
68 	} u;
69 };
70 
71 /*
72  * For a full 64-bit address space, there are 36 bits in play in an
73  * esid, so 8 levels, with the leaf being at level 0.
74  *
75  * |3333|3322|2222|2222|1111|1111|11  |    |    |  esid
76  * |5432|1098|7654|3210|9876|5432|1098|7654|3210|  bits
77  * +----+----+----+----+----+----+----+----+----+--------
78  * | 8  | 7  | 6  | 5  | 4  | 3  | 2  | 1  | 0  | level
79  */
80 #define UAD_ROOT_LEVEL  8
81 #define UAD_LEAF_LEVEL  0
82 
83 static inline int
84 esid2idx(uint64_t esid, int level)
85 {
86 	int shift;
87 
88 	shift = level * 4;
89 	return ((esid >> shift) & 0xF);
90 }
91 
92 /*
93  * The ua_base field should have 0 bits after the first 4*(level+1)
94  * bits; i.e. only
95  */
96 #define uad_baseok(ua)                          \
97 	(esid2base(ua->ua_base, ua->ua_level) == ua->ua_base)
98 
99 
100 static inline uint64_t
101 esid2base(uint64_t esid, int level)
102 {
103 	uint64_t mask;
104 	int shift;
105 
106 	shift = (level + 1) * 4;
107 	mask = ~((1ULL << shift) - 1);
108 	return (esid & mask);
109 }
110 
111 /*
112  * Allocate a new leaf node for the specified esid/vmhandle from the
113  * parent node.
114  */
115 static struct slb *
116 make_new_leaf(uint64_t esid, uint64_t slbv, struct slbtnode *parent)
117 {
118 	struct slbtnode *child;
119 	struct slb *retval;
120 	int idx;
121 
122 	idx = esid2idx(esid, parent->ua_level);
123 	KASSERT(parent->u.ua_child[idx] == NULL, ("Child already exists!"));
124 
125 	/* unlock and M_WAITOK and loop? */
126 	child = uma_zalloc(slbt_zone, M_NOWAIT | M_ZERO);
127 	KASSERT(child != NULL, ("unhandled NULL case"));
128 
129 	child->ua_level = UAD_LEAF_LEVEL;
130 	child->ua_base = esid2base(esid, child->ua_level);
131 	idx = esid2idx(esid, child->ua_level);
132 	child->u.slb_entries[idx].slbv = slbv;
133 	child->u.slb_entries[idx].slbe = (esid << SLBE_ESID_SHIFT) | SLBE_VALID;
134 	setbit(&child->ua_alloc, idx);
135 
136 	retval = &child->u.slb_entries[idx];
137 
138 	/*
139 	 * The above stores must be visible before the next one, so
140 	 * that a lockless searcher always sees a valid path through
141 	 * the tree.
142 	 */
143 	mb();
144 
145 	idx = esid2idx(esid, parent->ua_level);
146 	parent->u.ua_child[idx] = child;
147 	setbit(&parent->ua_alloc, idx);
148 
149 	return (retval);
150 }
151 
152 /*
153  * Allocate a new intermediate node to fit between the parent and
154  * esid.
155  */
156 static struct slbtnode*
157 make_intermediate(uint64_t esid, struct slbtnode *parent)
158 {
159 	struct slbtnode *child, *inter;
160 	int idx, level;
161 
162 	idx = esid2idx(esid, parent->ua_level);
163 	child = parent->u.ua_child[idx];
164 	KASSERT(esid2base(esid, child->ua_level) != child->ua_base,
165 	    ("No need for an intermediate node?"));
166 
167 	/*
168 	 * Find the level where the existing child and our new esid
169 	 * meet.  It must be lower than parent->ua_level or we would
170 	 * have chosen a different index in parent.
171 	 */
172 	level = child->ua_level + 1;
173 	while (esid2base(esid, level) !=
174 	    esid2base(child->ua_base, level))
175 		level++;
176 	KASSERT(level < parent->ua_level,
177 	    ("Found splitting level %d for %09jx and %09jx, "
178 	    "but it's the same as %p's",
179 	    level, esid, child->ua_base, parent));
180 
181 	/* unlock and M_WAITOK and loop? */
182 	inter = uma_zalloc(slbt_zone, M_NOWAIT | M_ZERO);
183 	KASSERT(inter != NULL, ("unhandled NULL case"));
184 
185 	/* Set up intermediate node to point to child ... */
186 	inter->ua_level = level;
187 	inter->ua_base = esid2base(esid, inter->ua_level);
188 	idx = esid2idx(child->ua_base, inter->ua_level);
189 	inter->u.ua_child[idx] = child;
190 	setbit(&inter->ua_alloc, idx);
191 	mb();
192 
193 	/* Set up parent to point to intermediate node ... */
194 	idx = esid2idx(inter->ua_base, parent->ua_level);
195 	parent->u.ua_child[idx] = inter;
196 	setbit(&parent->ua_alloc, idx);
197 
198 	return (inter);
199 }
200 
201 uint64_t
202 kernel_va_to_slbv(vm_offset_t va)
203 {
204 	uint64_t slbv;
205 
206 	/* Set kernel VSID to deterministic value */
207 	slbv = (KERNEL_VSID((uintptr_t)va >> ADDR_SR_SHFT)) << SLBV_VSID_SHIFT;
208 
209 	/* Figure out if this is a large-page mapping */
210 	if (hw_direct_map && va < VM_MIN_KERNEL_ADDRESS) {
211 		/*
212 		 * XXX: If we have set up a direct map, assumes
213 		 * all physical memory is mapped with large pages.
214 		 */
215 		if (mem_valid(va, 0) == 0)
216 			slbv |= SLBV_L;
217 	}
218 
219 	return (slbv);
220 }
221 
222 struct slb *
223 user_va_to_slb_entry(pmap_t pm, vm_offset_t va)
224 {
225 	uint64_t esid = va >> ADDR_SR_SHFT;
226 	struct slbtnode *ua;
227 	int idx;
228 
229 	ua = pm->pm_slb_tree_root;
230 
231 	for (;;) {
232 		KASSERT(uad_baseok(ua), ("uad base %016jx level %d bad!",
233 		    ua->ua_base, ua->ua_level));
234 		idx = esid2idx(esid, ua->ua_level);
235 
236 		/*
237 		 * This code is specific to ppc64 where a load is
238 		 * atomic, so no need for atomic_load macro.
239 		 */
240 		if (ua->ua_level == UAD_LEAF_LEVEL)
241 			return ((ua->u.slb_entries[idx].slbe & SLBE_VALID) ?
242 			    &ua->u.slb_entries[idx] : NULL);
243 
244 		ua = ua->u.ua_child[idx];
245 		if (ua == NULL ||
246 		    esid2base(esid, ua->ua_level) != ua->ua_base)
247 			return (NULL);
248 	}
249 
250 	return (NULL);
251 }
252 
253 uint64_t
254 va_to_vsid(pmap_t pm, vm_offset_t va)
255 {
256 	struct slb *entry;
257 
258 	/* Shortcut kernel case */
259 	if (pm == kernel_pmap)
260 		return (KERNEL_VSID((uintptr_t)va >> ADDR_SR_SHFT));
261 
262 	/*
263 	 * If there is no vsid for this VA, we need to add a new entry
264 	 * to the PMAP's segment table.
265 	 */
266 
267 	entry = user_va_to_slb_entry(pm, va);
268 
269 	if (entry == NULL)
270 		return (allocate_user_vsid(pm,
271 		    (uintptr_t)va >> ADDR_SR_SHFT, 0));
272 
273 	return ((entry->slbv & SLBV_VSID_MASK) >> SLBV_VSID_SHIFT);
274 }
275 
276 uint64_t
277 allocate_user_vsid(pmap_t pm, uint64_t esid, int large)
278 {
279 	uint64_t vsid, slbv;
280 	struct slbtnode *ua, *next, *inter;
281 	struct slb *slb;
282 	int idx;
283 
284 	KASSERT(pm != kernel_pmap, ("Attempting to allocate a kernel VSID"));
285 
286 	PMAP_LOCK_ASSERT(pm, MA_OWNED);
287 	vsid = moea64_get_unique_vsid();
288 
289 	slbv = vsid << SLBV_VSID_SHIFT;
290 	if (large)
291 		slbv |= SLBV_L;
292 
293 	ua = pm->pm_slb_tree_root;
294 
295 	/* Descend to the correct leaf or NULL pointer. */
296 	for (;;) {
297 		KASSERT(uad_baseok(ua),
298 		   ("uad base %09jx level %d bad!", ua->ua_base, ua->ua_level));
299 		idx = esid2idx(esid, ua->ua_level);
300 
301 		if (ua->ua_level == UAD_LEAF_LEVEL) {
302 			ua->u.slb_entries[idx].slbv = slbv;
303 			eieio();
304 			ua->u.slb_entries[idx].slbe = (esid << SLBE_ESID_SHIFT)
305 			    | SLBE_VALID;
306 			setbit(&ua->ua_alloc, idx);
307 			slb = &ua->u.slb_entries[idx];
308 			break;
309 		}
310 
311 		next = ua->u.ua_child[idx];
312 		if (next == NULL) {
313 			slb = make_new_leaf(esid, slbv, ua);
314 			break;
315                 }
316 
317 		/*
318 		 * Check if the next item down has an okay ua_base.
319 		 * If not, we need to allocate an intermediate node.
320 		 */
321 		if (esid2base(esid, next->ua_level) != next->ua_base) {
322 			inter = make_intermediate(esid, ua);
323 			slb = make_new_leaf(esid, slbv, inter);
324 			break;
325 		}
326 
327 		ua = next;
328 	}
329 
330 	/*
331 	 * Someone probably wants this soon, and it may be a wired
332 	 * SLB mapping, so pre-spill this entry.
333 	 */
334 	eieio();
335 	slb_insert_user(pm, slb);
336 
337 	return (vsid);
338 }
339 
340 void
341 free_vsid(pmap_t pm, uint64_t esid, int large)
342 {
343 	struct slbtnode *ua;
344 	int idx;
345 
346 	PMAP_LOCK_ASSERT(pm, MA_OWNED);
347 
348 	ua = pm->pm_slb_tree_root;
349 	/* Descend to the correct leaf. */
350 	for (;;) {
351 		KASSERT(uad_baseok(ua),
352 		   ("uad base %09jx level %d bad!", ua->ua_base, ua->ua_level));
353 
354 		idx = esid2idx(esid, ua->ua_level);
355 		if (ua->ua_level == UAD_LEAF_LEVEL) {
356 			ua->u.slb_entries[idx].slbv = 0;
357 			eieio();
358 			ua->u.slb_entries[idx].slbe = 0;
359 			clrbit(&ua->ua_alloc, idx);
360 			return;
361 		}
362 
363 		ua = ua->u.ua_child[idx];
364 		if (ua == NULL ||
365 		    esid2base(esid, ua->ua_level) != ua->ua_base) {
366 			/* Perhaps just return instead of assert? */
367 			KASSERT(0,
368 			    ("Asked to remove an entry that was never inserted!"));
369 			return;
370 		}
371 	}
372 }
373 
374 static void
375 free_slb_tree_node(struct slbtnode *ua)
376 {
377 	int idx;
378 
379 	for (idx = 0; idx < 16; idx++) {
380 		if (ua->ua_level != UAD_LEAF_LEVEL) {
381 			if (ua->u.ua_child[idx] != NULL)
382 				free_slb_tree_node(ua->u.ua_child[idx]);
383 		} else {
384 			if (ua->u.slb_entries[idx].slbv != 0)
385 				moea64_release_vsid(ua->u.slb_entries[idx].slbv
386 				    >> SLBV_VSID_SHIFT);
387 		}
388 	}
389 
390 	uma_zfree(slbt_zone, ua);
391 }
392 
393 void
394 slb_free_tree(pmap_t pm)
395 {
396 
397 	free_slb_tree_node(pm->pm_slb_tree_root);
398 }
399 
400 struct slbtnode *
401 slb_alloc_tree(void)
402 {
403 	struct slbtnode *root;
404 
405 	root = uma_zalloc(slbt_zone, M_NOWAIT | M_ZERO);
406 	root->ua_level = UAD_ROOT_LEVEL;
407 
408 	return (root);
409 }
410 
411 /* Lock entries mapping kernel text and stacks */
412 
413 void
414 slb_insert_kernel(uint64_t slbe, uint64_t slbv)
415 {
416 	struct slb *slbcache;
417 	int i;
418 
419 	/* We don't want to be preempted while modifying the kernel map */
420 	critical_enter();
421 
422 	slbcache = PCPU_GET(slb);
423 
424 	/* Check for an unused slot, abusing the user slot as a full flag */
425 	if (slbcache[USER_SLB_SLOT].slbe == 0) {
426 		for (i = 0; i < n_slbs; i++) {
427 			if (i == USER_SLB_SLOT)
428 				continue;
429 			if (!(slbcache[i].slbe & SLBE_VALID))
430 				goto fillkernslb;
431 		}
432 
433 		if (i == n_slbs)
434 			slbcache[USER_SLB_SLOT].slbe = 1;
435 	}
436 
437 	i = mftb() % n_slbs;
438 	if (i == USER_SLB_SLOT)
439 			i = (i+1) % n_slbs;
440 
441 fillkernslb:
442 	KASSERT(i != USER_SLB_SLOT,
443 	    ("Filling user SLB slot with a kernel mapping"));
444 	slbcache[i].slbv = slbv;
445 	slbcache[i].slbe = slbe | (uint64_t)i;
446 
447 	/* If it is for this CPU, put it in the SLB right away */
448 	if (pmap_bootstrapped) {
449 		/* slbie not required */
450 		__asm __volatile ("slbmte %0, %1" ::
451 		    "r"(slbcache[i].slbv), "r"(slbcache[i].slbe));
452 	}
453 
454 	critical_exit();
455 }
456 
457 void
458 slb_insert_user(pmap_t pm, struct slb *slb)
459 {
460 	int i;
461 
462 	PMAP_LOCK_ASSERT(pm, MA_OWNED);
463 
464 	if (pm->pm_slb_len < n_slbs) {
465 		i = pm->pm_slb_len;
466 		pm->pm_slb_len++;
467 	} else {
468 		i = mftb() % n_slbs;
469 	}
470 
471 	/* Note that this replacement is atomic with respect to trap_subr */
472 	pm->pm_slb[i] = slb;
473 }
474 
475 static void *
476 slb_uma_real_alloc(uma_zone_t zone, vm_size_t bytes, u_int8_t *flags, int wait)
477 {
478 	static vm_offset_t realmax = 0;
479 	void *va;
480 	vm_page_t m;
481 	int pflags;
482 
483 	if (realmax == 0)
484 		realmax = platform_real_maxaddr();
485 
486 	*flags = UMA_SLAB_PRIV;
487 	pflags = malloc2vm_flags(wait) | VM_ALLOC_NOOBJ | VM_ALLOC_WIRED;
488 
489 	for (;;) {
490 		m = vm_page_alloc_contig(NULL, 0, pflags, 1, 0, realmax,
491 		    PAGE_SIZE, PAGE_SIZE, VM_MEMATTR_DEFAULT);
492 		if (m == NULL) {
493 			if (wait & M_NOWAIT)
494 				return (NULL);
495 			VM_WAIT;
496 		} else
497                         break;
498         }
499 
500 	va = (void *) VM_PAGE_TO_PHYS(m);
501 
502 	if (!hw_direct_map)
503 		pmap_kenter((vm_offset_t)va, VM_PAGE_TO_PHYS(m));
504 
505 	if ((wait & M_ZERO) && (m->flags & PG_ZERO) == 0)
506 		bzero(va, PAGE_SIZE);
507 
508 	return (va);
509 }
510 
511 static void
512 slb_zone_init(void *dummy)
513 {
514 
515 	slbt_zone = uma_zcreate("SLB tree node", sizeof(struct slbtnode),
516 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM);
517 	slb_cache_zone = uma_zcreate("SLB cache",
518 	    (n_slbs + 1)*sizeof(struct slb *), NULL, NULL, NULL, NULL,
519 	    UMA_ALIGN_PTR, UMA_ZONE_VM);
520 
521 	if (platform_real_maxaddr() != VM_MAX_ADDRESS) {
522 		uma_zone_set_allocf(slb_cache_zone, slb_uma_real_alloc);
523 		uma_zone_set_allocf(slbt_zone, slb_uma_real_alloc);
524 	}
525 }
526 
527 struct slb **
528 slb_alloc_user_cache(void)
529 {
530 	return (uma_zalloc(slb_cache_zone, M_ZERO));
531 }
532 
533 void
534 slb_free_user_cache(struct slb **slb)
535 {
536 	uma_zfree(slb_cache_zone, slb);
537 }
538