xref: /titanic_41/usr/src/uts/sun4u/cpu/us3_common_mmu.c (revision 0d282d1376eb7ba06504448622a6d65726e4bd3e)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <sys/types.h>
29 #include <sys/systm.h>
30 #include <sys/sysmacros.h>
31 #include <sys/archsystm.h>
32 #include <sys/vmsystm.h>
33 #include <sys/machparam.h>
34 #include <sys/machsystm.h>
35 #include <vm/vm_dep.h>
36 #include <vm/hat_sfmmu.h>
37 #include <vm/seg_kmem.h>
38 #include <sys/cmn_err.h>
39 #include <sys/debug.h>
40 #include <sys/cpu_module.h>
41 #include <sys/sysmacros.h>
42 #include <sys/panic.h>
43 
44 /*
45  * Note that 'Cheetah PRM' refers to:
46  *   SPARC V9 JPS1 Implementation Supplement: Sun UltraSPARC-III
47  */
48 
49 /*
50  * pan_disable_ism_large_pages and pan_disable_large_pages are the Panther-
51  * specific versions of disable_ism_large_pages and disable_large_pages,
52  * and feed back into those two hat variables at hat initialization time,
53  * for Panther-only systems.
54  *
55  * chpjag_disable_ism_large_pages is the Ch/Jaguar-specific version of
56  * disable_ism_large_pages. Ditto for chjag_disable_large_pages.
57  */
58 static int panther_only = 0;
59 
60 static int pan_disable_ism_large_pages = ((1 << TTE64K) |
61 	(1 << TTE512K) | (1 << TTE256M));
62 static int pan_disable_large_pages = (1 << TTE256M);
63 static int pan_disable_auto_large_pages =  ((1 << TTE64K) |
64 	(1 << TTE512K) | (1 << TTE4M) | (1 << TTE256M));
65 
66 static int chjag_disable_ism_large_pages = ((1 << TTE64K) |
67 	(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
68 static int chjag_disable_large_pages = ((1 << TTE32M) | (1 << TTE256M));
69 static int chjag_disable_auto_large_pages = ((1 << TTE64K) |
70 	(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
71 
72 /*
73  * The function returns the USIII-IV mmu-specific values for the
74  * hat's disable_large_pages and disable_ism_large_pages variables.
75  * Currently the hat's disable_large_pages and disable_ism_large_pages
76  * already contain the generic sparc 4 page size info, and the return
77  * values are or'd with those values.
78  */
79 int
80 mmu_large_pages_disabled(uint_t flag)
81 {
82 	int pages_disable = 0;
83 
84 	if (panther_only) {
85 		if (flag == HAT_LOAD) {
86 			pages_disable = pan_disable_large_pages;
87 		} else if (flag == HAT_LOAD_SHARE) {
88 			pages_disable = pan_disable_ism_large_pages;
89 		} else if (flag == HAT_LOAD_AUTOLPG) {
90 			pages_disable = pan_disable_auto_large_pages;
91 		}
92 	} else {
93 		if (flag == HAT_LOAD) {
94 			pages_disable = chjag_disable_large_pages;
95 		} else if (flag == HAT_LOAD_SHARE) {
96 			pages_disable = chjag_disable_ism_large_pages;
97 		} else if (flag == HAT_LOAD_AUTOLPG) {
98 			pages_disable = chjag_disable_auto_large_pages;
99 		}
100 	}
101 	return (pages_disable);
102 }
103 
104 #if defined(CPU_IMP_DUAL_PAGESIZE)
105 /*
106  * If a platform is running with only Ch+ or Jaguar, and then someone DR's
107  * in a Panther board, the Panther mmu will not like it if one of the already
108  * running threads is context switched to the Panther and tries to program
109  * a 512K or 4M page into the T512_1. So make these platforms pay the price
110  * and follow the Panther DTLB restrictions by default. :)
111  * The mmu_init_mmu_page_sizes code below takes care of heterogeneous
112  * platforms that don't support DR, like daktari.
113  *
114  * The effect of these restrictions is to limit the allowable values in
115  * sfmmu_pgsz[0] and sfmmu_pgsz[1], since these hat variables are used in
116  * mmu_set_ctx_page_sizes to set up the values in the sfmmu_cext that
117  * are used at context switch time. The value in sfmmu_pgsz[0] is used in
118  * P_pgsz0 and sfmmu_pgsz[1] is used in P_pgsz1, as per Figure F-1-1
119  * IMMU and DMMU Primary Context Register in the Panther Implementation
120  * Supplement and Table 15-21 DMMU Primary Context Register in the
121  * Cheetah+ Delta PRM.
122  */
123 #ifdef MIXEDCPU_DR_SUPPORTED
124 int panther_dtlb_restrictions = 1;
125 #else
126 int panther_dtlb_restrictions = 0;
127 #endif /* MIXEDCPU_DR_SUPPORTED */
128 
129 /*
130  * init_mmu_page_sizes is set to one after the bootup time initialization
131  * via mmu_init_mmu_page_sizes, to indicate that mmu_page_sizes has a
132  * valid value.
133  */
134 int init_mmu_page_sizes = 0;
135 
136 /*
137  * mmu_init_large_pages is called with the desired ism_pagesize parameter,
138  * for Panther-only systems. It may be called from set_platform_defaults,
139  * if some value other than 32M is desired, for Panther-only systems.
140  * mmu_ism_pagesize is the tunable.  If it has a bad value, then only warn,
141  * since it would be bad form to panic due
142  * to a user typo.
143  *
144  * The function re-initializes the pan_disable_ism_large_pages and
145  * pan_disable_large_pages variables, which are closely related.
146  * Aka, if 32M is the desired [D]ISM page sizes, then 256M cannot be allowed
147  * for non-ISM large page usage, or DTLB conflict will occur. Please see the
148  * Panther PRM for additional DTLB technical info.
149  */
150 void
151 mmu_init_large_pages(size_t ism_pagesize)
152 {
153 	if (cpu_impl_dual_pgsz == 0) {	/* disable_dual_pgsz flag */
154 		pan_disable_ism_large_pages = ((1 << TTE64K) |
155 			(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
156 		pan_disable_large_pages = ((1 << TTE32M) | (1 << TTE256M));
157 		auto_lpg_maxszc = TTE4M;
158 		return;
159 	}
160 
161 	switch (ism_pagesize) {
162 	case MMU_PAGESIZE4M:
163 		pan_disable_ism_large_pages = ((1 << TTE64K) |
164 			(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
165 		pan_disable_large_pages = (1 << TTE256M);
166 		pan_disable_auto_large_pages = ((1 << TTE64K) |
167 			(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
168 		auto_lpg_maxszc = TTE4M;
169 		break;
170 	case MMU_PAGESIZE32M:
171 		pan_disable_ism_large_pages = ((1 << TTE64K) |
172 			(1 << TTE512K) | (1 << TTE256M));
173 		pan_disable_large_pages = (1 << TTE256M);
174 		pan_disable_auto_large_pages = ((1 << TTE64K) |
175 			(1 << TTE512K) | (1 << TTE4M) | (1 << TTE256M));
176 		auto_lpg_maxszc = TTE32M;
177 		break;
178 	case MMU_PAGESIZE256M:
179 		pan_disable_ism_large_pages = ((1 << TTE64K) |
180 			(1 << TTE512K) | (1 << TTE32M));
181 		pan_disable_large_pages = (1 << TTE32M);
182 		pan_disable_auto_large_pages = ((1 << TTE64K) |
183 			(1 << TTE512K) | (1 << TTE4M) | (1 << TTE32M));
184 		auto_lpg_maxszc = TTE256M;
185 		break;
186 	default:
187 		cmn_err(CE_WARN, "Unrecognized mmu_ism_pagesize value 0x%lx",
188 			ism_pagesize);
189 		break;
190 	}
191 }
192 
193 /*
194  * Re-initialize mmu_page_sizes and friends, for Panther mmu support.
195  * Called during very early bootup from check_cpus_set().
196  * Can be called to verify that mmu_page_sizes are set up correctly.
197  * Note that ncpus is not initialized at this point in the bootup sequence.
198  */
199 int
200 mmu_init_mmu_page_sizes(int cinfo)
201 {
202 	int npanther = cinfo;
203 
204 	if (!init_mmu_page_sizes) {
205 		if (npanther == ncpunode) {
206 			mmu_page_sizes = MMU_PAGE_SIZES;
207 			mmu_hashcnt = MAX_HASHCNT;
208 			mmu_ism_pagesize = MMU_PAGESIZE32M;
209 			mmu_exported_pagesize_mask = (1 << TTE8K) |
210 			    (1 << TTE64K) | (1 << TTE512K) | (1 << TTE4M) |
211 			    (1 << TTE32M) | (1 << TTE256M);
212 			panther_dtlb_restrictions = 1;
213 			panther_only = 1;
214 			auto_lpg_maxszc = TTE32M;
215 		} else if (npanther > 0) {
216 			panther_dtlb_restrictions = 1;
217 		}
218 		init_mmu_page_sizes = 1;
219 		return (0);
220 	}
221 	return (1);
222 }
223 
224 
225 /* Cheetah+ and later worst case DTLB parameters */
226 #ifndef	LOCKED_DTLB_ENTRIES
227 #define	LOCKED_DTLB_ENTRIES	5	/* 2 user TSBs, 2 nucleus, + OBP */
228 #endif
229 #define	TOTAL_DTLB_ENTRIES	16
230 #define	AVAIL_32M_ENTRIES	0
231 #define	AVAIL_256M_ENTRIES	0
232 #define	AVAIL_DTLB_ENTRIES	(TOTAL_DTLB_ENTRIES - LOCKED_DTLB_ENTRIES)
233 static uint64_t ttecnt_threshold[MMU_PAGE_SIZES] = {
234 	AVAIL_DTLB_ENTRIES, AVAIL_DTLB_ENTRIES,
235 	AVAIL_DTLB_ENTRIES, AVAIL_DTLB_ENTRIES,
236 	AVAIL_32M_ENTRIES, AVAIL_256M_ENTRIES };
237 
238 /*ARGSUSED*/
239 uint_t
240 mmu_preferred_pgsz(struct hat *hat, caddr_t addr, size_t len)
241 {
242 	sfmmu_t *sfmmup = (sfmmu_t *)hat;
243 	uint_t pgsz0, pgsz1;
244 	uint_t szc, maxszc = mmu_page_sizes - 1;
245 	size_t pgsz;
246 	extern int disable_auto_large_pages;
247 
248 	pgsz0 = (uint_t)sfmmup->sfmmu_pgsz[0];
249 	pgsz1 = (uint_t)sfmmup->sfmmu_pgsz[1];
250 
251 	/*
252 	 * If either of the TLBs are reprogrammed, choose
253 	 * the largest mapping size as the preferred size,
254 	 * if it fits the size and alignment constraints.
255 	 * Else return the largest mapping size that fits,
256 	 * if neither TLB is reprogrammed.
257 	 */
258 	if (pgsz0 > TTE8K || pgsz1 > TTE8K) {
259 		if (pgsz1 > pgsz0) {	/* First try pgsz1 */
260 			pgsz = hw_page_array[pgsz1].hp_size;
261 			if ((len >= pgsz) && IS_P2ALIGNED(addr, pgsz))
262 				return (pgsz1);
263 		}
264 		if (pgsz0 > TTE8K) {	/* Then try pgsz0, if !TTE8K */
265 			pgsz = hw_page_array[pgsz0].hp_size;
266 			if ((len >= pgsz) && IS_P2ALIGNED(addr, pgsz))
267 				return (pgsz0);
268 		}
269 	} else { /* Otherwise pick best fit if neither TLB is reprogrammed. */
270 		for (szc = maxszc; szc > TTE8K; szc--) {
271 			if (disable_auto_large_pages & (1 << szc))
272 				continue;
273 
274 			pgsz = hw_page_array[szc].hp_size;
275 			if ((len >= pgsz) && IS_P2ALIGNED(addr, pgsz))
276 				return (szc);
277 		}
278 	}
279 	return (TTE8K);
280 }
281 
282 /*
283  * The purpose of this code is to indirectly reorganize the sfmmu_pgsz array
284  * in order to handle the Panther mmu DTLB requirements. Panther only supports
285  * the 32M/256M pages in the T512_1 and not in the T16, so the Panther cpu
286  * can only support one of the two largest page sizes at a time (efficiently).
287  * Panther only supports 512K and 4M pages in the T512_0, and 32M/256M pages
288  * in the T512_1.  So check the sfmmu flags and ttecnt before enabling
289  * the T512_1 for 32M or 256M page sizes, and make sure that 512K and 4M
290  * requests go to the T512_0.
291  *
292  * The tmp_pgsz array comes into this routine in sorted order, as it is
293  * sorted from largest to smallest #pages per pagesize in use by the hat code,
294  * and leaves with the Panther mmu DTLB requirements satisfied. Note that
295  * when the array leaves this function it may not contain all of the page
296  * size codes that it had coming into the function.
297  *
298  * Note that for DISM the flag can be set but the ttecnt can be 0, if we
299  * didn't fault any pages in. This allows the t512_1 to be reprogrammed,
300  * because the T16 does not support the two giant page sizes. ouch.
301  */
302 void
303 mmu_fixup_large_pages(struct hat *hat, uint64_t *ttecnt, uint8_t *tmp_pgsz)
304 {
305 	uint_t pgsz0 = tmp_pgsz[0];
306 	uint_t pgsz1 = tmp_pgsz[1];
307 	uint_t spgsz;
308 
309 	/*
310 	 * Don't program 2nd dtlb for kernel and ism hat
311 	 */
312 	ASSERT(hat->sfmmu_ismhat == NULL);
313 	ASSERT(hat != ksfmmup);
314 	ASSERT(cpu_impl_dual_pgsz == 1);
315 
316 	ASSERT((!SFMMU_FLAGS_ISSET(hat, HAT_32M_FLAG)) ||
317 		(!SFMMU_FLAGS_ISSET(hat, HAT_256M_FLAG)));
318 
319 	if ((SFMMU_FLAGS_ISSET(hat, HAT_32M_FLAG)) || (ttecnt[TTE32M] != 0)) {
320 		spgsz = pgsz1;
321 		pgsz1 = TTE32M;
322 		if (pgsz0 == TTE32M)
323 			pgsz0 = spgsz;
324 	} else if ((SFMMU_FLAGS_ISSET(hat, HAT_256M_FLAG)) ||
325 	    (ttecnt[TTE256M] != 0)) {
326 		spgsz = pgsz1;
327 		pgsz1 = TTE256M;
328 		if (pgsz0 == TTE256M)
329 			pgsz0 = spgsz;
330 	} else if ((pgsz1 == TTE512K) || (pgsz1 == TTE4M)) {
331 		if ((pgsz0 != TTE512K) && (pgsz0 != TTE4M)) {
332 			spgsz = pgsz0;
333 			pgsz0 = pgsz1;
334 			pgsz1 = spgsz;
335 		} else {
336 			pgsz1 = page_szc(MMU_PAGESIZE);
337 		}
338 	}
339 	/*
340 	 * This implements PAGESIZE programming of the T8s
341 	 * if large TTE counts don't exceed the thresholds.
342 	 */
343 	if (ttecnt[pgsz0] < ttecnt_threshold[pgsz0])
344 		pgsz0 = page_szc(MMU_PAGESIZE);
345 	if (ttecnt[pgsz1] < ttecnt_threshold[pgsz1])
346 		pgsz1 = page_szc(MMU_PAGESIZE);
347 	tmp_pgsz[0] = pgsz0;
348 	tmp_pgsz[1] = pgsz1;
349 }
350 
351 /*
352  * Function to set up the page size values used to reprogram the DTLBs,
353  * when page sizes used by a process change significantly.
354  */
355 void
356 mmu_setup_page_sizes(struct hat *hat, uint64_t *ttecnt, uint8_t *tmp_pgsz)
357 {
358 	uint_t pgsz0, pgsz1;
359 
360 	/*
361 	 * Don't program 2nd dtlb for kernel and ism hat
362 	 */
363 	ASSERT(hat->sfmmu_ismhat == NULL);
364 	ASSERT(hat != ksfmmup);
365 
366 	if (cpu_impl_dual_pgsz == 0)	/* disable_dual_pgsz flag */
367 		return;
368 
369 	/*
370 	 * hat->sfmmu_pgsz[] is an array whose elements
371 	 * contain a sorted order of page sizes.  Element
372 	 * 0 is the most commonly used page size, followed
373 	 * by element 1, and so on.
374 	 *
375 	 * ttecnt[] is an array of per-page-size page counts
376 	 * mapped into the process.
377 	 *
378 	 * If the HAT's choice for page sizes is unsuitable,
379 	 * we can override it here.  The new values written
380 	 * to the array will be handed back to us later to
381 	 * do the actual programming of the TLB hardware.
382 	 *
383 	 * The policy we use for programming the dual T8s on
384 	 * Cheetah+ and beyond is as follows:
385 	 *
386 	 *   We have two programmable TLBs, so we look at
387 	 *   the two most common page sizes in the array, which
388 	 *   have already been computed for us by the HAT.
389 	 *   If the TTE count of either of a preferred page size
390 	 *   exceeds the number of unlocked T16 entries,
391 	 *   we reprogram one of the T8s to that page size
392 	 *   to avoid thrashing in the T16.  Else we program
393 	 *   that T8 to the base page size.  Note that we do
394 	 *   not force either T8 to be the base page size if a
395 	 *   process is using more than two page sizes.  Policy
396 	 *   decisions about which page sizes are best to use are
397 	 *   left to the upper layers.
398 	 *
399 	 *   Note that for Panther, 4M and 512K pages need to be
400 	 *   programmed into T512_0, and 32M and 256M into T512_1,
401 	 *   so we don't want to go through the MIN/MAX code.
402 	 *   For partial-Panther systems, we still want to make sure
403 	 *   that 4M and 512K page sizes NEVER get into the T512_1.
404 	 *   Since the DTLB flags are not set up on a per-cpu basis,
405 	 *   Panther rules must be applied for mixed Panther/Cheetah+/
406 	 *   Jaguar configurations.
407 	 */
408 	if (panther_dtlb_restrictions) {
409 		if ((tmp_pgsz[1] == TTE512K) || (tmp_pgsz[1] == TTE4M)) {
410 			if ((tmp_pgsz[0] != TTE512K) &&
411 			    (tmp_pgsz[0] != TTE4M)) {
412 				pgsz1 = tmp_pgsz[0];
413 				pgsz0 = tmp_pgsz[1];
414 			} else {
415 				pgsz0 = tmp_pgsz[0];
416 				pgsz1 = page_szc(MMU_PAGESIZE);
417 			}
418 		} else {
419 			pgsz0 = tmp_pgsz[0];
420 			pgsz1 = tmp_pgsz[1];
421 		}
422 	} else {
423 		pgsz0 = MIN(tmp_pgsz[0], tmp_pgsz[1]);
424 		pgsz1 = MAX(tmp_pgsz[0], tmp_pgsz[1]);
425 	}
426 
427 	/*
428 	 * This implements PAGESIZE programming of the T8s
429 	 * if large TTE counts don't exceed the thresholds.
430 	 */
431 	if (ttecnt[pgsz0] < ttecnt_threshold[pgsz0])
432 		pgsz0 = page_szc(MMU_PAGESIZE);
433 	if (ttecnt[pgsz1] < ttecnt_threshold[pgsz1])
434 		pgsz1 = page_szc(MMU_PAGESIZE);
435 	tmp_pgsz[0] = pgsz0;
436 	tmp_pgsz[1] = pgsz1;
437 }
438 
439 /*
440  * The HAT calls this function when an MMU context is allocated so that we
441  * can reprogram the large TLBs appropriately for the new process using
442  * the context.
443  *
444  * The caller must hold the HAT lock.
445  */
446 void
447 mmu_set_ctx_page_sizes(struct hat *hat)
448 {
449 	uint_t pgsz0, pgsz1;
450 	uint_t new_cext;
451 
452 	ASSERT(sfmmu_hat_lock_held(hat));
453 	ASSERT(hat != ksfmmup);
454 
455 	if (cpu_impl_dual_pgsz == 0)	/* disable_dual_pgsz flag */
456 		return;
457 
458 	/*
459 	 * If supported, reprogram the TLBs to a larger pagesize.
460 	 */
461 	pgsz0 = hat->sfmmu_pgsz[0];
462 	pgsz1 = hat->sfmmu_pgsz[1];
463 	ASSERT(pgsz0 < mmu_page_sizes);
464 	ASSERT(pgsz1 < mmu_page_sizes);
465 #ifdef DEBUG
466 	if (panther_dtlb_restrictions) {
467 		ASSERT(pgsz1 != TTE512K);
468 		ASSERT(pgsz1 != TTE4M);
469 	}
470 	if (panther_only) {
471 		ASSERT(pgsz0 != TTE32M);
472 		ASSERT(pgsz0 != TTE256M);
473 	}
474 #endif /* DEBUG */
475 	new_cext = TAGACCEXT_MKSZPAIR(pgsz1, pgsz0);
476 	if (hat->sfmmu_cext != new_cext) {
477 #ifdef DEBUG
478 		int i;
479 		/*
480 		 * assert cnum should be invalid, this is because pagesize
481 		 * can only be changed after a proc's ctxs are invalidated.
482 		 */
483 		for (i = 0; i < max_mmu_ctxdoms; i++) {
484 			ASSERT(hat->sfmmu_ctxs[i].cnum == INVALID_CONTEXT);
485 		}
486 #endif /* DEBUG */
487 		hat->sfmmu_cext = new_cext;
488 	}
489 
490 	/*
491 	 * sfmmu_setctx_sec() will take care of the
492 	 * rest of the chores reprogramming the hat->sfmmu_cext
493 	 * page size values into the DTLBs.
494 	 */
495 }
496 
497 /*
498  * This function assumes that there are either four or six supported page
499  * sizes and at most two programmable TLBs, so we need to decide which
500  * page sizes are most important and then adjust the TLB page sizes
501  * accordingly (if supported).
502  *
503  * If these assumptions change, this function will need to be
504  * updated to support whatever the new limits are.
505  */
506 void
507 mmu_check_page_sizes(sfmmu_t *sfmmup, uint64_t *ttecnt)
508 {
509 	uint64_t sortcnt[MMU_PAGE_SIZES];
510 	uint8_t tmp_pgsz[MMU_PAGE_SIZES];
511 	uint8_t i, j, max;
512 	uint16_t oldval, newval;
513 
514 	/*
515 	 * We only consider reprogramming the TLBs if one or more of
516 	 * the two most used page sizes changes and we're using
517 	 * large pages in this process, except for Panther 32M/256M pages,
518 	 * which the Panther T16 does not support.
519 	 */
520 	if (sfmmup->sfmmu_flags & HAT_LGPG_FLAGS) {
521 		/* Sort page sizes. */
522 		for (i = 0; i < mmu_page_sizes; i++) {
523 			sortcnt[i] = ttecnt[i];
524 		}
525 		for (j = 0; j < mmu_page_sizes; j++) {
526 			for (i = mmu_page_sizes - 1, max = 0; i > 0; i--) {
527 				if (sortcnt[i] > sortcnt[max])
528 					max = i;
529 			}
530 			tmp_pgsz[j] = max;
531 			sortcnt[max] = 0;
532 		}
533 
534 		/*
535 		 * Handle Panther page dtlb calcs separately. The check
536 		 * for actual or potential 32M/256M pages must occur
537 		 * every time due to lack of T16 support for them.
538 		 * The sort works fine for Ch+/Jag, but Panther has
539 		 * pagesize restrictions for both DTLBs.
540 		 */
541 		oldval = sfmmup->sfmmu_pgsz[0] << 8 | sfmmup->sfmmu_pgsz[1];
542 
543 		if (panther_only) {
544 			mmu_fixup_large_pages(sfmmup, ttecnt, tmp_pgsz);
545 		} else {
546 			/* Check 2 largest values after the sort. */
547 			mmu_setup_page_sizes(sfmmup, ttecnt, tmp_pgsz);
548 		}
549 		newval = tmp_pgsz[0] << 8 | tmp_pgsz[1];
550 		if (newval != oldval) {
551 			sfmmu_reprog_pgsz_arr(sfmmup, tmp_pgsz);
552 		}
553 	}
554 }
555 
556 #endif	/* CPU_IMP_DUAL_PAGESIZE */
557 
558 struct heap_lp_page_size {
559 	int    impl;
560 	uint_t tte;
561 	int    use_dt512;
562 };
563 
564 struct heap_lp_page_size heap_lp_pgsz[] = {
565 
566 	{CHEETAH_IMPL, TTE8K, 0},		/* default */
567 	{CHEETAH_IMPL, TTE64K, 0},
568 	{CHEETAH_IMPL, TTE4M, 0},
569 
570 	{ CHEETAH_PLUS_IMPL, TTE4M,  1 },	/* default */
571 	{ CHEETAH_PLUS_IMPL, TTE4M,  0 },
572 	{ CHEETAH_PLUS_IMPL, TTE64K, 1 },
573 	{ CHEETAH_PLUS_IMPL, TTE64K, 0 },
574 	{ CHEETAH_PLUS_IMPL, TTE8K,  0 },
575 
576 	{ JALAPENO_IMPL, TTE4M,  1 },		/* default */
577 	{ JALAPENO_IMPL, TTE4M,  0 },
578 	{ JALAPENO_IMPL, TTE64K, 1 },
579 	{ JALAPENO_IMPL, TTE64K, 0 },
580 	{ JALAPENO_IMPL, TTE8K,  0 },
581 
582 	{ JAGUAR_IMPL, TTE4M, 1 },		/* default */
583 	{ JAGUAR_IMPL, TTE4M, 0 },
584 	{ JAGUAR_IMPL, TTE64K, 1 },
585 	{ JAGUAR_IMPL, TTE64K, 0 },
586 	{ JAGUAR_IMPL, TTE8K, 0 },
587 
588 	{ SERRANO_IMPL, TTE4M,  1 },		/* default */
589 	{ SERRANO_IMPL, TTE4M,  0 },
590 	{ SERRANO_IMPL, TTE64K, 1 },
591 	{ SERRANO_IMPL, TTE64K, 0 },
592 	{ SERRANO_IMPL, TTE8K,  0 },
593 
594 	{ PANTHER_IMPL, TTE4M, 1 },		/* default */
595 	{ PANTHER_IMPL, TTE4M, 0 },
596 	{ PANTHER_IMPL, TTE64K, 1 },
597 	{ PANTHER_IMPL, TTE64K, 0 },
598 	{ PANTHER_IMPL, TTE8K, 0 }
599 };
600 
601 int	heaplp_use_dt512 = -1;
602 
603 void
604 mmu_init_kernel_pgsz(struct hat *hat)
605 {
606 	uint_t tte = page_szc(segkmem_lpsize);
607 	uchar_t new_cext_primary, new_cext_nucleus;
608 
609 	if (heaplp_use_dt512 == 0 || tte > TTE4M) {
610 		/* do not reprogram dt512 tlb */
611 		tte = TTE8K;
612 	}
613 
614 	new_cext_nucleus = TAGACCEXT_MKSZPAIR(tte, TTE8K);
615 	new_cext_primary = TAGACCEXT_MKSZPAIR(TTE8K, tte);
616 
617 	hat->sfmmu_cext = new_cext_primary;
618 	kcontextreg = ((uint64_t)new_cext_nucleus << CTXREG_NEXT_SHIFT) |
619 		((uint64_t)new_cext_primary << CTXREG_EXT_SHIFT);
620 	mmu_init_kcontext();
621 }
622 
623 size_t
624 mmu_get_kernel_lpsize(size_t lpsize)
625 {
626 	struct heap_lp_page_size *p_lpgsz, *pend_lpgsz;
627 	int impl = cpunodes[getprocessorid()].implementation;
628 	uint_t tte = TTE8K;
629 
630 	if (cpu_impl_dual_pgsz == 0) {
631 		heaplp_use_dt512 = 0;
632 		return (MMU_PAGESIZE);
633 	}
634 
635 	pend_lpgsz = (struct heap_lp_page_size *)
636 	    ((char *)heap_lp_pgsz + sizeof (heap_lp_pgsz));
637 
638 	/* search for a valid segkmem_lpsize */
639 	for (p_lpgsz = heap_lp_pgsz; p_lpgsz < pend_lpgsz; p_lpgsz++) {
640 		if (impl != p_lpgsz->impl)
641 			continue;
642 
643 		if (lpsize == 0) {
644 			/*
645 			 * no setting for segkmem_lpsize in /etc/system
646 			 * use default from the table
647 			 */
648 			tte = p_lpgsz->tte;
649 			heaplp_use_dt512 = p_lpgsz->use_dt512;
650 			break;
651 		}
652 
653 		if (lpsize == TTEBYTES(p_lpgsz->tte) &&
654 		    (heaplp_use_dt512 == -1 ||
655 			heaplp_use_dt512 == p_lpgsz->use_dt512)) {
656 
657 			tte = p_lpgsz->tte;
658 			heaplp_use_dt512 = p_lpgsz->use_dt512;
659 
660 			/* found a match */
661 			break;
662 		}
663 	}
664 
665 	if (p_lpgsz == pend_lpgsz) {
666 		/* nothing found: disable large page kernel heap */
667 		tte = TTE8K;
668 		heaplp_use_dt512 = 0;
669 	}
670 
671 	lpsize = TTEBYTES(tte);
672 
673 	return (lpsize);
674 }
675