xref: /illumos-gate/usr/src/uts/sun4u/cpu/us3_common_mmu.c (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
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 2008 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  * pan_disable_ism_large_pages and pan_disable_large_pages are the Panther-
46  * specific versions of disable_ism_large_pages and disable_large_pages,
47  * and feed back into those two hat variables at hat initialization time,
48  * for Panther-only systems.
49  *
50  * chpjag_disable_large_pages is the Ch/Jaguar-specific version of
51  * disable_large_pages. Ditto for pan_disable_large_pages.
52  * Note that the Panther and Ch/Jaguar ITLB do not support 32M/256M pages.
53  */
54 static int panther_only = 0;
55 
56 static uint_t pan_disable_large_pages = (1 << TTE256M);
57 static uint_t chjag_disable_large_pages = ((1 << TTE32M) | (1 << TTE256M));
58 
59 static uint_t mmu_disable_ism_large_pages = ((1 << TTE64K) |
60 	(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
61 static uint_t mmu_disable_auto_data_large_pages =  ((1 << TTE64K) |
62 	(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
63 static uint_t mmu_disable_auto_text_large_pages =  ((1 << TTE64K) |
64 	(1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
65 
66 /*
67  * The function returns the USIII+(i)-IV+ mmu-specific values for the
68  * hat's disable_large_pages and disable_ism_large_pages variables.
69  * Currently the hat's disable_large_pages and disable_ism_large_pages
70  * already contain the generic sparc 4 page size info, and the return
71  * values are or'd with those values.
72  */
73 uint_t
74 mmu_large_pages_disabled(uint_t flag)
75 {
76 	uint_t pages_disable = 0;
77 	extern int use_text_pgsz64K;
78 	extern int use_text_pgsz512K;
79 
80 	if (flag == HAT_LOAD) {
81 		if (panther_only) {
82 			pages_disable = pan_disable_large_pages;
83 		} else {
84 			pages_disable = chjag_disable_large_pages;
85 		}
86 	} else if (flag == HAT_LOAD_SHARE) {
87 		pages_disable = mmu_disable_ism_large_pages;
88 	} else if (flag == HAT_AUTO_DATA) {
89 		pages_disable = mmu_disable_auto_data_large_pages;
90 	} else if (flag == HAT_AUTO_TEXT) {
91 		pages_disable = mmu_disable_auto_text_large_pages;
92 		if (use_text_pgsz512K) {
93 			pages_disable &= ~(1 << TTE512K);
94 		}
95 		if (use_text_pgsz64K) {
96 			pages_disable &= ~(1 << TTE64K);
97 		}
98 	}
99 	return (pages_disable);
100 }
101 
102 #if defined(CPU_IMP_DUAL_PAGESIZE)
103 /*
104  * If a platform is running with only Ch+ or Jaguar, and then someone DR's
105  * in a Panther board, the Panther mmu will not like it if one of the already
106  * running threads is context switched to the Panther and tries to program
107  * a 512K or 4M page into the T512_1. So make these platforms pay the price
108  * and follow the Panther DTLB restrictions by default. :)
109  * The mmu_init_mmu_page_sizes code below takes care of heterogeneous
110  * platforms that don't support DR, like daktari.
111  *
112  * The effect of these restrictions is to limit the allowable values in
113  * sfmmu_pgsz[0] and sfmmu_pgsz[1], since these hat variables are used in
114  * mmu_set_ctx_page_sizes to set up the values in the sfmmu_cext that
115  * are used at context switch time. The value in sfmmu_pgsz[0] is used in
116  * P_pgsz0 and sfmmu_pgsz[1] is used in P_pgsz1, as per Figure F-1-1
117  * IMMU and DMMU Primary Context Register in the Panther Implementation
118  * Supplement and Table 15-21 DMMU Primary Context Register in the
119  * Cheetah+ Delta PRM.
120  */
121 #ifdef MIXEDCPU_DR_SUPPORTED
122 int panther_dtlb_restrictions = 1;
123 #else
124 int panther_dtlb_restrictions = 0;
125 #endif /* MIXEDCPU_DR_SUPPORTED */
126 
127 /*
128  * init_mmu_page_sizes is set to one after the bootup time initialization
129  * via mmu_init_mmu_page_sizes, to indicate that mmu_page_sizes has a
130  * valid value.
131  */
132 int init_mmu_page_sizes = 0;
133 
134 /*
135  * mmu_init_large_pages is called with the desired ism_pagesize parameter,
136  * for Panther-only systems. It may be called from set_platform_defaults,
137  * if some value other than 4M is desired, for Panther-only systems.
138  * mmu_ism_pagesize is the tunable.  If it has a bad value, then only warn,
139  * since it would be bad form to panic due
140  * to a user typo.
141  *
142  * The function re-initializes the disable_ism_large_pages and
143  * pan_disable_large_pages variables, which are closely related.
144  * Aka, if 32M is the desired [D]ISM page sizes, then 256M cannot be allowed
145  * for non-ISM large page usage, or DTLB conflict will occur. Please see the
146  * Panther PRM for additional DTLB technical info.
147  */
148 void
149 mmu_init_large_pages(size_t ism_pagesize)
150 {
151 	if (cpu_impl_dual_pgsz == 0) {	/* disable_dual_pgsz flag */
152 		pan_disable_large_pages = ((1 << TTE32M) | (1 << TTE256M));
153 		mmu_disable_ism_large_pages = ((1 << TTE64K) |
154 		    (1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
155 		mmu_disable_auto_data_large_pages = ((1 << TTE64K) |
156 		    (1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
157 		return;
158 	}
159 
160 	switch (ism_pagesize) {
161 	case MMU_PAGESIZE4M:
162 		pan_disable_large_pages = (1 << TTE256M);
163 		mmu_disable_ism_large_pages = ((1 << TTE64K) |
164 		    (1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
165 		mmu_disable_auto_data_large_pages = ((1 << TTE64K) |
166 		    (1 << TTE512K) | (1 << TTE32M) | (1 << TTE256M));
167 		break;
168 	case MMU_PAGESIZE32M:
169 		pan_disable_large_pages = (1 << TTE256M);
170 		mmu_disable_ism_large_pages = ((1 << TTE64K) |
171 		    (1 << TTE512K) | (1 << TTE256M));
172 		mmu_disable_auto_data_large_pages = ((1 << TTE64K) |
173 		    (1 << TTE512K) | (1 << TTE4M) | (1 << TTE256M));
174 		adjust_data_maxlpsize(ism_pagesize);
175 		break;
176 	case MMU_PAGESIZE256M:
177 		pan_disable_large_pages = (1 << TTE32M);
178 		mmu_disable_ism_large_pages = ((1 << TTE64K) |
179 		    (1 << TTE512K) | (1 << TTE32M));
180 		mmu_disable_auto_data_large_pages = ((1 << TTE64K) |
181 		    (1 << TTE512K) | (1 << TTE4M) | (1 << TTE32M));
182 		adjust_data_maxlpsize(ism_pagesize);
183 		break;
184 	default:
185 		cmn_err(CE_WARN, "Unrecognized mmu_ism_pagesize value 0x%lx",
186 		    ism_pagesize);
187 		break;
188 	}
189 }
190 
191 /*
192  * Re-initialize mmu_page_sizes and friends, for Panther mmu support.
193  * Called during very early bootup from check_cpus_set().
194  * Can be called to verify that mmu_page_sizes are set up correctly.
195  * Note that ncpus is not initialized at this point in the bootup sequence.
196  */
197 int
198 mmu_init_mmu_page_sizes(int cinfo)
199 {
200 	int npanther = cinfo;
201 
202 	if (!init_mmu_page_sizes) {
203 		if (npanther == ncpunode) {
204 			mmu_page_sizes = MMU_PAGE_SIZES;
205 			mmu_hashcnt = MAX_HASHCNT;
206 			mmu_ism_pagesize = DEFAULT_ISM_PAGESIZE;
207 			mmu_exported_pagesize_mask = (1 << TTE8K) |
208 			    (1 << TTE64K) | (1 << TTE512K) | (1 << TTE4M) |
209 			    (1 << TTE32M) | (1 << TTE256M);
210 			panther_dtlb_restrictions = 1;
211 			panther_only = 1;
212 		} else if (npanther > 0) {
213 			panther_dtlb_restrictions = 1;
214 		}
215 		init_mmu_page_sizes = 1;
216 		return (0);
217 	}
218 	return (1);
219 }
220 
221 
222 /* Cheetah+ and later worst case DTLB parameters */
223 #ifndef	LOCKED_DTLB_ENTRIES
224 #define	LOCKED_DTLB_ENTRIES	5	/* 2 user TSBs, 2 nucleus, + OBP */
225 #endif
226 #define	TOTAL_DTLB_ENTRIES	16
227 #define	AVAIL_32M_ENTRIES	0
228 #define	AVAIL_256M_ENTRIES	0
229 #define	AVAIL_DTLB_ENTRIES	(TOTAL_DTLB_ENTRIES - LOCKED_DTLB_ENTRIES)
230 static uint64_t ttecnt_threshold[MMU_PAGE_SIZES] = {
231 	AVAIL_DTLB_ENTRIES, AVAIL_DTLB_ENTRIES,
232 	AVAIL_DTLB_ENTRIES, AVAIL_DTLB_ENTRIES,
233 	AVAIL_32M_ENTRIES, AVAIL_256M_ENTRIES };
234 
235 /*
236  * The purpose of this code is to indirectly reorganize the sfmmu_pgsz array
237  * in order to handle the Panther mmu DTLB requirements. Panther only supports
238  * the 32M/256M pages in the T512_1 and not in the T16, so the Panther cpu
239  * can only support one of the two largest page sizes at a time (efficiently).
240  * Panther only supports 512K and 4M pages in the T512_0, and 32M/256M pages
241  * in the T512_1.  So check the sfmmu flags and ttecnt before enabling
242  * the T512_1 for 32M or 256M page sizes, and make sure that 512K and 4M
243  * requests go to the T512_0.
244  *
245  * The tmp_pgsz array comes into this routine in sorted order, as it is
246  * sorted from largest to smallest #pages per pagesize in use by the hat code,
247  * and leaves with the Panther mmu DTLB requirements satisfied. Note that
248  * when the array leaves this function it may not contain all of the page
249  * size codes that it had coming into the function.
250  *
251  * Note that for DISM the flag can be set but the ttecnt can be 0, if we
252  * didn't fault any pages in. This allows the t512_1 to be reprogrammed,
253  * because the T16 does not support the two giant page sizes. ouch.
254  */
255 static void
256 mmu_fixup_large_pages(struct hat *hat, uint64_t *ttecnt, uint8_t *tmp_pgsz)
257 {
258 	uint_t pgsz0 = tmp_pgsz[0];
259 	uint_t pgsz1 = tmp_pgsz[1];
260 	uint_t spgsz;
261 
262 	/*
263 	 * Don't program 2nd dtlb for kernel and ism hat
264 	 */
265 	ASSERT(hat->sfmmu_ismhat == 0);
266 	ASSERT(hat != ksfmmup);
267 	ASSERT(cpu_impl_dual_pgsz == 1);
268 
269 	ASSERT(!SFMMU_TTEFLAGS_ISSET(hat, HAT_32M_FLAG) ||
270 	    !SFMMU_TTEFLAGS_ISSET(hat, HAT_256M_FLAG));
271 	ASSERT(!SFMMU_TTEFLAGS_ISSET(hat, HAT_256M_FLAG) ||
272 	    !SFMMU_TTEFLAGS_ISSET(hat, HAT_32M_FLAG));
273 	ASSERT(!SFMMU_FLAGS_ISSET(hat, HAT_32M_ISM) ||
274 	    !SFMMU_FLAGS_ISSET(hat, HAT_256M_ISM));
275 	ASSERT(!SFMMU_FLAGS_ISSET(hat, HAT_256M_ISM) ||
276 	    !SFMMU_FLAGS_ISSET(hat, HAT_32M_ISM));
277 
278 	if (SFMMU_TTEFLAGS_ISSET(hat, HAT_32M_FLAG) ||
279 	    (ttecnt[TTE32M] != 0) ||
280 	    SFMMU_FLAGS_ISSET(hat, HAT_32M_ISM)) {
281 
282 		spgsz = pgsz1;
283 		pgsz1 = TTE32M;
284 		if (pgsz0 == TTE32M)
285 			pgsz0 = spgsz;
286 
287 	} else if (SFMMU_TTEFLAGS_ISSET(hat, HAT_256M_FLAG) ||
288 	    (ttecnt[TTE256M] != 0) ||
289 	    SFMMU_FLAGS_ISSET(hat, HAT_256M_ISM)) {
290 
291 		spgsz = pgsz1;
292 		pgsz1 = TTE256M;
293 		if (pgsz0 == TTE256M)
294 			pgsz0 = spgsz;
295 
296 	} else if ((pgsz1 == TTE512K) || (pgsz1 == TTE4M)) {
297 		if ((pgsz0 != TTE512K) && (pgsz0 != TTE4M)) {
298 			spgsz = pgsz0;
299 			pgsz0 = pgsz1;
300 			pgsz1 = spgsz;
301 		} else {
302 			pgsz1 = page_szc(MMU_PAGESIZE);
303 		}
304 	}
305 	/*
306 	 * This implements PAGESIZE programming of the T8s
307 	 * if large TTE counts don't exceed the thresholds.
308 	 */
309 	if (ttecnt[pgsz0] < ttecnt_threshold[pgsz0])
310 		pgsz0 = page_szc(MMU_PAGESIZE);
311 	if (ttecnt[pgsz1] < ttecnt_threshold[pgsz1])
312 		pgsz1 = page_szc(MMU_PAGESIZE);
313 	tmp_pgsz[0] = pgsz0;
314 	tmp_pgsz[1] = pgsz1;
315 }
316 
317 /*
318  * Function to set up the page size values used to reprogram the DTLBs,
319  * when page sizes used by a process change significantly.
320  */
321 static void
322 mmu_setup_page_sizes(struct hat *hat, uint64_t *ttecnt, uint8_t *tmp_pgsz)
323 {
324 	uint_t pgsz0, pgsz1;
325 
326 	/*
327 	 * Don't program 2nd dtlb for kernel and ism hat
328 	 */
329 	ASSERT(hat->sfmmu_ismhat == NULL);
330 	ASSERT(hat != ksfmmup);
331 
332 	if (cpu_impl_dual_pgsz == 0)	/* disable_dual_pgsz flag */
333 		return;
334 
335 	/*
336 	 * hat->sfmmu_pgsz[] is an array whose elements
337 	 * contain a sorted order of page sizes.  Element
338 	 * 0 is the most commonly used page size, followed
339 	 * by element 1, and so on.
340 	 *
341 	 * ttecnt[] is an array of per-page-size page counts
342 	 * mapped into the process.
343 	 *
344 	 * If the HAT's choice for page sizes is unsuitable,
345 	 * we can override it here.  The new values written
346 	 * to the array will be handed back to us later to
347 	 * do the actual programming of the TLB hardware.
348 	 *
349 	 * The policy we use for programming the dual T8s on
350 	 * Cheetah+ and beyond is as follows:
351 	 *
352 	 *   We have two programmable TLBs, so we look at
353 	 *   the two most common page sizes in the array, which
354 	 *   have already been computed for us by the HAT.
355 	 *   If the TTE count of either of a preferred page size
356 	 *   exceeds the number of unlocked T16 entries,
357 	 *   we reprogram one of the T8s to that page size
358 	 *   to avoid thrashing in the T16.  Else we program
359 	 *   that T8 to the base page size.  Note that we do
360 	 *   not force either T8 to be the base page size if a
361 	 *   process is using more than two page sizes.  Policy
362 	 *   decisions about which page sizes are best to use are
363 	 *   left to the upper layers.
364 	 *
365 	 *   Note that for Panther, 4M and 512K pages need to be
366 	 *   programmed into T512_0, and 32M and 256M into T512_1,
367 	 *   so we don't want to go through the MIN/MAX code.
368 	 *   For partial-Panther systems, we still want to make sure
369 	 *   that 4M and 512K page sizes NEVER get into the T512_1.
370 	 *   Since the DTLB flags are not set up on a per-cpu basis,
371 	 *   Panther rules must be applied for mixed Panther/Cheetah+/
372 	 *   Jaguar configurations.
373 	 */
374 	if (panther_dtlb_restrictions) {
375 		if ((tmp_pgsz[1] == TTE512K) || (tmp_pgsz[1] == TTE4M)) {
376 			if ((tmp_pgsz[0] != TTE512K) &&
377 			    (tmp_pgsz[0] != TTE4M)) {
378 				pgsz1 = tmp_pgsz[0];
379 				pgsz0 = tmp_pgsz[1];
380 			} else {
381 				pgsz0 = tmp_pgsz[0];
382 				pgsz1 = page_szc(MMU_PAGESIZE);
383 			}
384 		} else {
385 			pgsz0 = tmp_pgsz[0];
386 			pgsz1 = tmp_pgsz[1];
387 		}
388 	} else {
389 		pgsz0 = MIN(tmp_pgsz[0], tmp_pgsz[1]);
390 		pgsz1 = MAX(tmp_pgsz[0], tmp_pgsz[1]);
391 	}
392 
393 	/*
394 	 * This implements PAGESIZE programming of the T8s
395 	 * if large TTE counts don't exceed the thresholds.
396 	 */
397 	if (ttecnt[pgsz0] < ttecnt_threshold[pgsz0])
398 		pgsz0 = page_szc(MMU_PAGESIZE);
399 	if (ttecnt[pgsz1] < ttecnt_threshold[pgsz1])
400 		pgsz1 = page_szc(MMU_PAGESIZE);
401 	tmp_pgsz[0] = pgsz0;
402 	tmp_pgsz[1] = pgsz1;
403 }
404 
405 /*
406  * The HAT calls this function when an MMU context is allocated so that we
407  * can reprogram the large TLBs appropriately for the new process using
408  * the context.
409  *
410  * The caller must hold the HAT lock.
411  */
412 void
413 mmu_set_ctx_page_sizes(struct hat *hat)
414 {
415 	uint_t pgsz0, pgsz1;
416 	uint_t new_cext;
417 
418 	ASSERT(sfmmu_hat_lock_held(hat));
419 	ASSERT(hat != ksfmmup);
420 
421 	if (cpu_impl_dual_pgsz == 0)	/* disable_dual_pgsz flag */
422 		return;
423 
424 	/*
425 	 * If supported, reprogram the TLBs to a larger pagesize.
426 	 */
427 	pgsz0 = hat->sfmmu_pgsz[0];
428 	pgsz1 = hat->sfmmu_pgsz[1];
429 	ASSERT(pgsz0 < mmu_page_sizes);
430 	ASSERT(pgsz1 < mmu_page_sizes);
431 #ifdef DEBUG
432 	if (panther_dtlb_restrictions) {
433 		ASSERT(pgsz1 != TTE512K);
434 		ASSERT(pgsz1 != TTE4M);
435 	}
436 	if (panther_only) {
437 		ASSERT(pgsz0 != TTE32M);
438 		ASSERT(pgsz0 != TTE256M);
439 	}
440 #endif /* DEBUG */
441 	new_cext = TAGACCEXT_MKSZPAIR(pgsz1, pgsz0);
442 	if (hat->sfmmu_cext != new_cext) {
443 #ifdef DEBUG
444 		int i;
445 		/*
446 		 * assert cnum should be invalid, this is because pagesize
447 		 * can only be changed after a proc's ctxs are invalidated.
448 		 */
449 		for (i = 0; i < max_mmu_ctxdoms; i++) {
450 			ASSERT(hat->sfmmu_ctxs[i].cnum == INVALID_CONTEXT);
451 		}
452 #endif /* DEBUG */
453 		hat->sfmmu_cext = new_cext;
454 	}
455 
456 	/*
457 	 * sfmmu_setctx_sec() will take care of the
458 	 * rest of the chores reprogramming the hat->sfmmu_cext
459 	 * page size values into the DTLBs.
460 	 */
461 }
462 
463 /*
464  * This function assumes that there are either four or six supported page
465  * sizes and at most two programmable TLBs, so we need to decide which
466  * page sizes are most important and then adjust the TLB page sizes
467  * accordingly (if supported).
468  *
469  * If these assumptions change, this function will need to be
470  * updated to support whatever the new limits are.
471  */
472 void
473 mmu_check_page_sizes(sfmmu_t *sfmmup, uint64_t *ttecnt)
474 {
475 	uint64_t sortcnt[MMU_PAGE_SIZES];
476 	uint8_t tmp_pgsz[MMU_PAGE_SIZES];
477 	uint8_t i, j, max;
478 	uint16_t oldval, newval;
479 
480 	/*
481 	 * We only consider reprogramming the TLBs if one or more of
482 	 * the two most used page sizes changes and we're using
483 	 * large pages in this process, except for Panther 32M/256M pages,
484 	 * which the Panther T16 does not support.
485 	 */
486 	if (SFMMU_LGPGS_INUSE(sfmmup)) {
487 		/* Sort page sizes. */
488 		for (i = 0; i < mmu_page_sizes; i++) {
489 			sortcnt[i] = ttecnt[i];
490 		}
491 		for (j = 0; j < mmu_page_sizes; j++) {
492 			for (i = mmu_page_sizes - 1, max = 0; i > 0; i--) {
493 				if (sortcnt[i] > sortcnt[max])
494 					max = i;
495 			}
496 			tmp_pgsz[j] = max;
497 			sortcnt[max] = 0;
498 		}
499 
500 		/*
501 		 * Handle Panther page dtlb calcs separately. The check
502 		 * for actual or potential 32M/256M pages must occur
503 		 * every time due to lack of T16 support for them.
504 		 * The sort works fine for Ch+/Jag, but Panther has
505 		 * pagesize restrictions for both DTLBs.
506 		 */
507 		oldval = sfmmup->sfmmu_pgsz[0] << 8 | sfmmup->sfmmu_pgsz[1];
508 
509 		if (panther_only) {
510 			mmu_fixup_large_pages(sfmmup, ttecnt, tmp_pgsz);
511 		} else {
512 			/* Check 2 largest values after the sort. */
513 			mmu_setup_page_sizes(sfmmup, ttecnt, tmp_pgsz);
514 		}
515 		newval = tmp_pgsz[0] << 8 | tmp_pgsz[1];
516 		if (newval != oldval) {
517 			sfmmu_reprog_pgsz_arr(sfmmup, tmp_pgsz);
518 		}
519 	}
520 }
521 
522 #endif	/* CPU_IMP_DUAL_PAGESIZE */
523 
524 struct heap_lp_page_size {
525 	int    impl;
526 	uint_t tte;
527 	int    use_dt512;
528 };
529 
530 struct heap_lp_page_size heap_lp_pgsz[] = {
531 
532 	{CHEETAH_IMPL, TTE8K, 0},		/* default */
533 	{CHEETAH_IMPL, TTE64K, 0},
534 	{CHEETAH_IMPL, TTE4M, 0},
535 
536 	{ CHEETAH_PLUS_IMPL, TTE4M,  1 },	/* default */
537 	{ CHEETAH_PLUS_IMPL, TTE4M,  0 },
538 	{ CHEETAH_PLUS_IMPL, TTE64K, 1 },
539 	{ CHEETAH_PLUS_IMPL, TTE64K, 0 },
540 	{ CHEETAH_PLUS_IMPL, TTE8K,  0 },
541 
542 	{ JALAPENO_IMPL, TTE4M,  1 },		/* default */
543 	{ JALAPENO_IMPL, TTE4M,  0 },
544 	{ JALAPENO_IMPL, TTE64K, 1 },
545 	{ JALAPENO_IMPL, TTE64K, 0 },
546 	{ JALAPENO_IMPL, TTE8K,  0 },
547 
548 	{ JAGUAR_IMPL, TTE4M, 1 },		/* default */
549 	{ JAGUAR_IMPL, TTE4M, 0 },
550 	{ JAGUAR_IMPL, TTE64K, 1 },
551 	{ JAGUAR_IMPL, TTE64K, 0 },
552 	{ JAGUAR_IMPL, TTE8K, 0 },
553 
554 	{ SERRANO_IMPL, TTE4M,  1 },		/* default */
555 	{ SERRANO_IMPL, TTE4M,  0 },
556 	{ SERRANO_IMPL, TTE64K, 1 },
557 	{ SERRANO_IMPL, TTE64K, 0 },
558 	{ SERRANO_IMPL, TTE8K,  0 },
559 
560 	{ PANTHER_IMPL, TTE4M, 1 },		/* default */
561 	{ PANTHER_IMPL, TTE4M, 0 },
562 	{ PANTHER_IMPL, TTE64K, 1 },
563 	{ PANTHER_IMPL, TTE64K, 0 },
564 	{ PANTHER_IMPL, TTE8K, 0 }
565 };
566 
567 int	heaplp_use_dt512 = -1;
568 
569 void
570 mmu_init_kernel_pgsz(struct hat *hat)
571 {
572 	uint_t tte = page_szc(segkmem_lpsize);
573 	uchar_t new_cext_primary, new_cext_nucleus;
574 
575 	if (heaplp_use_dt512 == 0 || tte > TTE4M) {
576 		/* do not reprogram dt512 tlb */
577 		tte = TTE8K;
578 	}
579 
580 	new_cext_nucleus = TAGACCEXT_MKSZPAIR(tte, TTE8K);
581 	new_cext_primary = TAGACCEXT_MKSZPAIR(TTE8K, tte);
582 
583 	hat->sfmmu_cext = new_cext_primary;
584 	kcontextreg = ((uint64_t)new_cext_nucleus << CTXREG_NEXT_SHIFT) |
585 	    ((uint64_t)new_cext_primary << CTXREG_EXT_SHIFT);
586 }
587 
588 size_t
589 mmu_get_kernel_lpsize(size_t lpsize)
590 {
591 	struct heap_lp_page_size *p_lpgsz, *pend_lpgsz;
592 	int impl = cpunodes[getprocessorid()].implementation;
593 	uint_t tte = TTE8K;
594 
595 	if (cpu_impl_dual_pgsz == 0) {
596 		heaplp_use_dt512 = 0;
597 		return (MMU_PAGESIZE);
598 	}
599 
600 	pend_lpgsz = (struct heap_lp_page_size *)
601 	    ((char *)heap_lp_pgsz + sizeof (heap_lp_pgsz));
602 
603 	/* search for a valid segkmem_lpsize */
604 	for (p_lpgsz = heap_lp_pgsz; p_lpgsz < pend_lpgsz; p_lpgsz++) {
605 		if (impl != p_lpgsz->impl)
606 			continue;
607 
608 		if (lpsize == 0) {
609 			/*
610 			 * no setting for segkmem_lpsize in /etc/system
611 			 * use default from the table
612 			 */
613 			tte = p_lpgsz->tte;
614 			heaplp_use_dt512 = p_lpgsz->use_dt512;
615 			break;
616 		}
617 
618 		if (lpsize == TTEBYTES(p_lpgsz->tte) &&
619 		    (heaplp_use_dt512 == -1 ||
620 		    heaplp_use_dt512 == p_lpgsz->use_dt512)) {
621 
622 			tte = p_lpgsz->tte;
623 			heaplp_use_dt512 = p_lpgsz->use_dt512;
624 
625 			/* found a match */
626 			break;
627 		}
628 	}
629 
630 	if (p_lpgsz == pend_lpgsz) {
631 		/* nothing found: disable large page kernel heap */
632 		tte = TTE8K;
633 		heaplp_use_dt512 = 0;
634 	}
635 
636 	lpsize = TTEBYTES(tte);
637 
638 	return (lpsize);
639 }
640