xref: /freebsd/sys/x86/x86/x86_mem.c (revision 7cc42f6d)
1 /*-
2  * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
3  * Copyright (c) 2017 The FreeBSD Foundation
4  * All rights reserved.
5  *
6  * Portions of this software were developed by Konstantin Belousov
7  * under sponsorship from the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/systm.h>
37 #include <sys/malloc.h>
38 #include <sys/memrange.h>
39 #include <sys/smp.h>
40 #include <sys/sysctl.h>
41 
42 #include <vm/vm.h>
43 #include <vm/vm_param.h>
44 #include <vm/pmap.h>
45 
46 #include <machine/cputypes.h>
47 #include <machine/md_var.h>
48 #include <machine/specialreg.h>
49 
50 /*
51  * Pentium Pro+ memory range operations
52  *
53  * This code will probably be impenetrable without reference to the
54  * Intel Pentium Pro documentation or x86-64 programmers manual vol 2.
55  */
56 
57 static char *mem_owner_bios = "BIOS";
58 
59 #define	MR686_FIXMTRR	(1<<0)
60 
61 #define	mrwithin(mr, a)							\
62 	(((a) >= (mr)->mr_base) && ((a) < ((mr)->mr_base + (mr)->mr_len)))
63 #define	mroverlap(mra, mrb)						\
64 	(mrwithin(mra, mrb->mr_base) || mrwithin(mrb, mra->mr_base))
65 
66 #define	mrvalid(base, len) 						\
67 	((!(base & ((1 << 12) - 1))) &&	/* base is multiple of 4k */	\
68 	    ((len) >= (1 << 12)) &&	/* length is >= 4k */		\
69 	    powerof2((len)) &&		/* ... and power of two */	\
70 	    !((base) & ((len) - 1)))	/* range is not discontiuous */
71 
72 #define	mrcopyflags(curr, new)						\
73 	(((curr) & ~MDF_ATTRMASK) | ((new) & MDF_ATTRMASK))
74 
75 static int mtrrs_disabled;
76 SYSCTL_INT(_machdep, OID_AUTO, disable_mtrrs, CTLFLAG_RDTUN,
77     &mtrrs_disabled, 0,
78     "Disable MTRRs.");
79 
80 static void	x86_mrinit(struct mem_range_softc *sc);
81 static int	x86_mrset(struct mem_range_softc *sc,
82 		    struct mem_range_desc *mrd, int *arg);
83 static void	x86_mrAPinit(struct mem_range_softc *sc);
84 static void	x86_mrreinit(struct mem_range_softc *sc);
85 
86 static struct mem_range_ops x86_mrops = {
87 	x86_mrinit,
88 	x86_mrset,
89 	x86_mrAPinit,
90 	x86_mrreinit
91 };
92 
93 /* XXX for AP startup hook */
94 static u_int64_t mtrrcap, mtrrdef;
95 
96 /* The bitmask for the PhysBase and PhysMask fields of the variable MTRRs. */
97 static u_int64_t mtrr_physmask;
98 
99 static struct mem_range_desc *mem_range_match(struct mem_range_softc *sc,
100 		    struct mem_range_desc *mrd);
101 static void	x86_mrfetch(struct mem_range_softc *sc);
102 static int	x86_mtrrtype(int flags);
103 static int	x86_mrt2mtrr(int flags, int oldval);
104 static int	x86_mtrrconflict(int flag1, int flag2);
105 static void	x86_mrstore(struct mem_range_softc *sc);
106 static void	x86_mrstoreone(void *arg);
107 static struct mem_range_desc *x86_mtrrfixsearch(struct mem_range_softc *sc,
108 		    u_int64_t addr);
109 static int	x86_mrsetlow(struct mem_range_softc *sc,
110 		    struct mem_range_desc *mrd, int *arg);
111 static int	x86_mrsetvariable(struct mem_range_softc *sc,
112 		    struct mem_range_desc *mrd, int *arg);
113 
114 /* ia32 MTRR type to memory range type conversion */
115 static int x86_mtrrtomrt[] = {
116 	MDF_UNCACHEABLE,
117 	MDF_WRITECOMBINE,
118 	MDF_UNKNOWN,
119 	MDF_UNKNOWN,
120 	MDF_WRITETHROUGH,
121 	MDF_WRITEPROTECT,
122 	MDF_WRITEBACK
123 };
124 
125 #define	MTRRTOMRTLEN nitems(x86_mtrrtomrt)
126 
127 static int
128 x86_mtrr2mrt(int val)
129 {
130 
131 	if (val < 0 || val >= MTRRTOMRTLEN)
132 		return (MDF_UNKNOWN);
133 	return (x86_mtrrtomrt[val]);
134 }
135 
136 /*
137  * x86 MTRR conflicts. Writeback and uncachable may overlap.
138  */
139 static int
140 x86_mtrrconflict(int flag1, int flag2)
141 {
142 
143 	flag1 &= MDF_ATTRMASK;
144 	flag2 &= MDF_ATTRMASK;
145 	if ((flag1 & MDF_UNKNOWN) || (flag2 & MDF_UNKNOWN))
146 		return (1);
147 	if (flag1 == flag2 ||
148 	    (flag1 == MDF_WRITEBACK && flag2 == MDF_UNCACHEABLE) ||
149 	    (flag2 == MDF_WRITEBACK && flag1 == MDF_UNCACHEABLE))
150 		return (0);
151 	return (1);
152 }
153 
154 /*
155  * Look for an exactly-matching range.
156  */
157 static struct mem_range_desc *
158 mem_range_match(struct mem_range_softc *sc, struct mem_range_desc *mrd)
159 {
160 	struct mem_range_desc *cand;
161 	int i;
162 
163 	for (i = 0, cand = sc->mr_desc; i < sc->mr_ndesc; i++, cand++)
164 		if ((cand->mr_base == mrd->mr_base) &&
165 		    (cand->mr_len == mrd->mr_len))
166 			return (cand);
167 	return (NULL);
168 }
169 
170 /*
171  * Ensure that the direct map region does not contain any mappings
172  * that span MTRRs of different types.  However, the fixed MTRRs can
173  * be ignored, because a large page mapping the first 1 MB of physical
174  * memory is a special case that the processor handles.  Invalidate
175  * any old TLB entries that might hold inconsistent memory type
176  * information.
177  */
178 static void
179 x86_mr_split_dmap(struct mem_range_softc *sc __unused)
180 {
181 #ifdef __amd64__
182 	struct mem_range_desc *mrd;
183 	int i;
184 
185 	i = (sc->mr_cap & MR686_FIXMTRR) ? MTRR_N64K + MTRR_N16K + MTRR_N4K : 0;
186 	mrd = sc->mr_desc + i;
187 	for (; i < sc->mr_ndesc; i++, mrd++) {
188 		if ((mrd->mr_flags & (MDF_ACTIVE | MDF_BOGUS)) == MDF_ACTIVE)
189 			pmap_demote_DMAP(mrd->mr_base, mrd->mr_len, TRUE);
190 	}
191 #endif
192 }
193 
194 /*
195  * Fetch the current mtrr settings from the current CPU (assumed to
196  * all be in sync in the SMP case).  Note that if we are here, we
197  * assume that MTRRs are enabled, and we may or may not have fixed
198  * MTRRs.
199  */
200 static void
201 x86_mrfetch(struct mem_range_softc *sc)
202 {
203 	struct mem_range_desc *mrd;
204 	u_int64_t msrv;
205 	int i, j, msr;
206 
207 	mrd = sc->mr_desc;
208 
209 	/* Get fixed-range MTRRs. */
210 	if (sc->mr_cap & MR686_FIXMTRR) {
211 		msr = MSR_MTRR64kBase;
212 		for (i = 0; i < (MTRR_N64K / 8); i++, msr++) {
213 			msrv = rdmsr(msr);
214 			for (j = 0; j < 8; j++, mrd++) {
215 				mrd->mr_flags =
216 				    (mrd->mr_flags & ~MDF_ATTRMASK) |
217 				    x86_mtrr2mrt(msrv & 0xff) | MDF_ACTIVE;
218 				if (mrd->mr_owner[0] == 0)
219 					strcpy(mrd->mr_owner, mem_owner_bios);
220 				msrv = msrv >> 8;
221 			}
222 		}
223 		msr = MSR_MTRR16kBase;
224 		for (i = 0; i < MTRR_N16K / 8; i++, msr++) {
225 			msrv = rdmsr(msr);
226 			for (j = 0; j < 8; j++, mrd++) {
227 				mrd->mr_flags =
228 				    (mrd->mr_flags & ~MDF_ATTRMASK) |
229 				    x86_mtrr2mrt(msrv & 0xff) | MDF_ACTIVE;
230 				if (mrd->mr_owner[0] == 0)
231 					strcpy(mrd->mr_owner, mem_owner_bios);
232 				msrv = msrv >> 8;
233 			}
234 		}
235 		msr = MSR_MTRR4kBase;
236 		for (i = 0; i < MTRR_N4K / 8; i++, msr++) {
237 			msrv = rdmsr(msr);
238 			for (j = 0; j < 8; j++, mrd++) {
239 				mrd->mr_flags =
240 				    (mrd->mr_flags & ~MDF_ATTRMASK) |
241 				    x86_mtrr2mrt(msrv & 0xff) | MDF_ACTIVE;
242 				if (mrd->mr_owner[0] == 0)
243 					strcpy(mrd->mr_owner, mem_owner_bios);
244 				msrv = msrv >> 8;
245 			}
246 		}
247 	}
248 
249 	/* Get remainder which must be variable MTRRs. */
250 	msr = MSR_MTRRVarBase;
251 	for (; mrd - sc->mr_desc < sc->mr_ndesc; msr += 2, mrd++) {
252 		msrv = rdmsr(msr);
253 		mrd->mr_flags = (mrd->mr_flags & ~MDF_ATTRMASK) |
254 		    x86_mtrr2mrt(msrv & MTRR_PHYSBASE_TYPE);
255 		mrd->mr_base = msrv & mtrr_physmask;
256 		msrv = rdmsr(msr + 1);
257 		mrd->mr_flags = (msrv & MTRR_PHYSMASK_VALID) ?
258 		    (mrd->mr_flags | MDF_ACTIVE) :
259 		    (mrd->mr_flags & ~MDF_ACTIVE);
260 
261 		/* Compute the range from the mask. Ick. */
262 		mrd->mr_len = (~(msrv & mtrr_physmask) &
263 		    (mtrr_physmask | 0xfff)) + 1;
264 		if (!mrvalid(mrd->mr_base, mrd->mr_len))
265 			mrd->mr_flags |= MDF_BOGUS;
266 
267 		/* If unclaimed and active, must be the BIOS. */
268 		if ((mrd->mr_flags & MDF_ACTIVE) && (mrd->mr_owner[0] == 0))
269 			strcpy(mrd->mr_owner, mem_owner_bios);
270 	}
271 }
272 
273 /*
274  * Return the MTRR memory type matching a region's flags
275  */
276 static int
277 x86_mtrrtype(int flags)
278 {
279 	int i;
280 
281 	flags &= MDF_ATTRMASK;
282 
283 	for (i = 0; i < MTRRTOMRTLEN; i++) {
284 		if (x86_mtrrtomrt[i] == MDF_UNKNOWN)
285 			continue;
286 		if (flags == x86_mtrrtomrt[i])
287 			return (i);
288 	}
289 	return (-1);
290 }
291 
292 static int
293 x86_mrt2mtrr(int flags, int oldval)
294 {
295 	int val;
296 
297 	if ((val = x86_mtrrtype(flags)) == -1)
298 		return (oldval & 0xff);
299 	return (val & 0xff);
300 }
301 
302 /*
303  * Update running CPU(s) MTRRs to match the ranges in the descriptor
304  * list.
305  *
306  * Must be called with interrupts enabled.
307  */
308 static void
309 x86_mrstore(struct mem_range_softc *sc)
310 {
311 
312 	smp_rendezvous(NULL, x86_mrstoreone, NULL, sc);
313 }
314 
315 /*
316  * Update the current CPU's MTRRs with those represented in the
317  * descriptor list.  Note that we do this wholesale rather than just
318  * stuffing one entry; this is simpler (but slower, of course).
319  */
320 static void
321 x86_mrstoreone(void *arg)
322 {
323 	struct mem_range_softc *sc = arg;
324 	struct mem_range_desc *mrd;
325 	u_int64_t omsrv, msrv;
326 	int i, j, msr;
327 	u_long cr0, cr4;
328 
329 	mrd = sc->mr_desc;
330 
331 	critical_enter();
332 
333 	/* Disable PGE. */
334 	cr4 = rcr4();
335 	load_cr4(cr4 & ~CR4_PGE);
336 
337 	/* Disable caches (CD = 1, NW = 0). */
338 	cr0 = rcr0();
339 	load_cr0((cr0 & ~CR0_NW) | CR0_CD);
340 
341 	/* Flushes caches and TLBs. */
342 	wbinvd();
343 	invltlb();
344 
345 	/* Disable MTRRs (E = 0). */
346 	wrmsr(MSR_MTRRdefType, rdmsr(MSR_MTRRdefType) & ~MTRR_DEF_ENABLE);
347 
348 	/* Set fixed-range MTRRs. */
349 	if (sc->mr_cap & MR686_FIXMTRR) {
350 		msr = MSR_MTRR64kBase;
351 		for (i = 0; i < MTRR_N64K / 8; i++, msr++) {
352 			msrv = 0;
353 			omsrv = rdmsr(msr);
354 			for (j = 7; j >= 0; j--) {
355 				msrv = msrv << 8;
356 				msrv |= x86_mrt2mtrr((mrd + j)->mr_flags,
357 				    omsrv >> (j * 8));
358 			}
359 			wrmsr(msr, msrv);
360 			mrd += 8;
361 		}
362 		msr = MSR_MTRR16kBase;
363 		for (i = 0; i < MTRR_N16K / 8; i++, msr++) {
364 			msrv = 0;
365 			omsrv = rdmsr(msr);
366 			for (j = 7; j >= 0; j--) {
367 				msrv = msrv << 8;
368 				msrv |= x86_mrt2mtrr((mrd + j)->mr_flags,
369 				    omsrv >> (j * 8));
370 			}
371 			wrmsr(msr, msrv);
372 			mrd += 8;
373 		}
374 		msr = MSR_MTRR4kBase;
375 		for (i = 0; i < MTRR_N4K / 8; i++, msr++) {
376 			msrv = 0;
377 			omsrv = rdmsr(msr);
378 			for (j = 7; j >= 0; j--) {
379 				msrv = msrv << 8;
380 				msrv |= x86_mrt2mtrr((mrd + j)->mr_flags,
381 				    omsrv >> (j * 8));
382 			}
383 			wrmsr(msr, msrv);
384 			mrd += 8;
385 		}
386 	}
387 
388 	/* Set remainder which must be variable MTRRs. */
389 	msr = MSR_MTRRVarBase;
390 	for (; mrd - sc->mr_desc < sc->mr_ndesc; msr += 2, mrd++) {
391 		/* base/type register */
392 		omsrv = rdmsr(msr);
393 		if (mrd->mr_flags & MDF_ACTIVE) {
394 			msrv = mrd->mr_base & mtrr_physmask;
395 			msrv |= x86_mrt2mtrr(mrd->mr_flags, omsrv);
396 		} else {
397 			msrv = 0;
398 		}
399 		wrmsr(msr, msrv);
400 
401 		/* mask/active register */
402 		if (mrd->mr_flags & MDF_ACTIVE) {
403 			msrv = MTRR_PHYSMASK_VALID |
404 			    rounddown2(mtrr_physmask, mrd->mr_len);
405 		} else {
406 			msrv = 0;
407 		}
408 		wrmsr(msr + 1, msrv);
409 	}
410 
411 	/* Flush caches and TLBs. */
412 	wbinvd();
413 	invltlb();
414 
415 	/* Enable MTRRs. */
416 	wrmsr(MSR_MTRRdefType, rdmsr(MSR_MTRRdefType) | MTRR_DEF_ENABLE);
417 
418 	/* Restore caches and PGE. */
419 	load_cr0(cr0);
420 	load_cr4(cr4);
421 
422 	critical_exit();
423 }
424 
425 /*
426  * Hunt for the fixed MTRR referencing (addr)
427  */
428 static struct mem_range_desc *
429 x86_mtrrfixsearch(struct mem_range_softc *sc, u_int64_t addr)
430 {
431 	struct mem_range_desc *mrd;
432 	int i;
433 
434 	for (i = 0, mrd = sc->mr_desc; i < MTRR_N64K + MTRR_N16K + MTRR_N4K;
435 	     i++, mrd++)
436 		if (addr >= mrd->mr_base &&
437 		    addr < mrd->mr_base + mrd->mr_len)
438 			return (mrd);
439 	return (NULL);
440 }
441 
442 /*
443  * Try to satisfy the given range request by manipulating the fixed
444  * MTRRs that cover low memory.
445  *
446  * Note that we try to be generous here; we'll bloat the range out to
447  * the next higher/lower boundary to avoid the consumer having to know
448  * too much about the mechanisms here.
449  *
450  * XXX note that this will have to be updated when we start supporting
451  * "busy" ranges.
452  */
453 static int
454 x86_mrsetlow(struct mem_range_softc *sc, struct mem_range_desc *mrd, int *arg)
455 {
456 	struct mem_range_desc *first_md, *last_md, *curr_md;
457 
458 	/* Range check. */
459 	if ((first_md = x86_mtrrfixsearch(sc, mrd->mr_base)) == NULL ||
460 	    (last_md = x86_mtrrfixsearch(sc, mrd->mr_base + mrd->mr_len - 1))
461 	    == NULL)
462 		return (EINVAL);
463 
464 	/* Check that we aren't doing something risky. */
465 	if ((mrd->mr_flags & MDF_FORCE) == 0) {
466 		for (curr_md = first_md; curr_md <= last_md; curr_md++) {
467 			if ((curr_md->mr_flags & MDF_ATTRMASK) == MDF_UNKNOWN)
468 				return (EACCES);
469 		}
470 	}
471 
472 	/* Set flags, clear set-by-firmware flag. */
473 	for (curr_md = first_md; curr_md <= last_md; curr_md++) {
474 		curr_md->mr_flags = mrcopyflags(curr_md->mr_flags &
475 		    ~MDF_FIRMWARE, mrd->mr_flags);
476 		bcopy(mrd->mr_owner, curr_md->mr_owner, sizeof(mrd->mr_owner));
477 	}
478 
479 	return (0);
480 }
481 
482 /*
483  * Modify/add a variable MTRR to satisfy the request.
484  *
485  * XXX needs to be updated to properly support "busy" ranges.
486  */
487 static int
488 x86_mrsetvariable(struct mem_range_softc *sc, struct mem_range_desc *mrd,
489     int *arg)
490 {
491 	struct mem_range_desc *curr_md, *free_md;
492 	int i;
493 
494 	/*
495 	 * Scan the currently active variable descriptors, look for
496 	 * one we exactly match (straight takeover) and for possible
497 	 * accidental overlaps.
498 	 *
499 	 * Keep track of the first empty variable descriptor in case
500 	 * we can't perform a takeover.
501 	 */
502 	i = (sc->mr_cap & MR686_FIXMTRR) ? MTRR_N64K + MTRR_N16K + MTRR_N4K : 0;
503 	curr_md = sc->mr_desc + i;
504 	free_md = NULL;
505 	for (; i < sc->mr_ndesc; i++, curr_md++) {
506 		if (curr_md->mr_flags & MDF_ACTIVE) {
507 			/* Exact match? */
508 			if (curr_md->mr_base == mrd->mr_base &&
509 			    curr_md->mr_len == mrd->mr_len) {
510 				/* Whoops, owned by someone. */
511 				if (curr_md->mr_flags & MDF_BUSY)
512 					return (EBUSY);
513 
514 				/* Check that we aren't doing something risky */
515 				if (!(mrd->mr_flags & MDF_FORCE) &&
516 				    (curr_md->mr_flags & MDF_ATTRMASK) ==
517 				    MDF_UNKNOWN)
518 					return (EACCES);
519 
520 				/* Ok, just hijack this entry. */
521 				free_md = curr_md;
522 				break;
523 			}
524 
525 			/* Non-exact overlap? */
526 			if (mroverlap(curr_md, mrd)) {
527 				/* Between conflicting region types? */
528 				if (x86_mtrrconflict(curr_md->mr_flags,
529 				    mrd->mr_flags))
530 					return (EINVAL);
531 			}
532 		} else if (free_md == NULL) {
533 			free_md = curr_md;
534 		}
535 	}
536 
537 	/* Got somewhere to put it? */
538 	if (free_md == NULL)
539 		return (ENOSPC);
540 
541 	/* Set up new descriptor. */
542 	free_md->mr_base = mrd->mr_base;
543 	free_md->mr_len = mrd->mr_len;
544 	free_md->mr_flags = mrcopyflags(MDF_ACTIVE, mrd->mr_flags);
545 	bcopy(mrd->mr_owner, free_md->mr_owner, sizeof(mrd->mr_owner));
546 	return (0);
547 }
548 
549 /*
550  * Handle requests to set memory range attributes by manipulating MTRRs.
551  */
552 static int
553 x86_mrset(struct mem_range_softc *sc, struct mem_range_desc *mrd, int *arg)
554 {
555 	struct mem_range_desc *targ;
556 	int error;
557 
558 	switch (*arg) {
559 	case MEMRANGE_SET_UPDATE:
560 		/*
561 		 * Make sure that what's being asked for is even
562 		 * possible at all.
563 		 */
564 		if (!mrvalid(mrd->mr_base, mrd->mr_len) ||
565 		    x86_mtrrtype(mrd->mr_flags) == -1)
566 			return (EINVAL);
567 
568 #define	FIXTOP	\
569     ((MTRR_N64K * 0x10000) + (MTRR_N16K * 0x4000) + (MTRR_N4K * 0x1000))
570 
571 		/* Are the "low memory" conditions applicable? */
572 		if ((sc->mr_cap & MR686_FIXMTRR) != 0 &&
573 		    mrd->mr_base + mrd->mr_len <= FIXTOP) {
574 			if ((error = x86_mrsetlow(sc, mrd, arg)) != 0)
575 				return (error);
576 		} else {
577 			/* It's time to play with variable MTRRs. */
578 			if ((error = x86_mrsetvariable(sc, mrd, arg)) != 0)
579 				return (error);
580 		}
581 		break;
582 
583 	case MEMRANGE_SET_REMOVE:
584 		if ((targ = mem_range_match(sc, mrd)) == NULL)
585 			return (ENOENT);
586 		if (targ->mr_flags & MDF_FIXACTIVE)
587 			return (EPERM);
588 		if (targ->mr_flags & MDF_BUSY)
589 			return (EBUSY);
590 		targ->mr_flags &= ~MDF_ACTIVE;
591 		targ->mr_owner[0] = 0;
592 		break;
593 
594 	default:
595 		return (EOPNOTSUPP);
596 	}
597 
598 	x86_mr_split_dmap(sc);
599 
600 	/* Update the hardware. */
601 	x86_mrstore(sc);
602 
603 	/* Refetch to see where we're at. */
604 	x86_mrfetch(sc);
605 	return (0);
606 }
607 
608 /*
609  * Work out how many ranges we support, initialise storage for them,
610  * and fetch the initial settings.
611  */
612 static void
613 x86_mrinit(struct mem_range_softc *sc)
614 {
615 	struct mem_range_desc *mrd;
616 	int i, nmdesc;
617 
618 	if (sc->mr_desc != NULL)
619 		/* Already initialized. */
620 		return;
621 
622 	nmdesc = 0;
623 	mtrrcap = rdmsr(MSR_MTRRcap);
624 	mtrrdef = rdmsr(MSR_MTRRdefType);
625 
626 	/* For now, bail out if MTRRs are not enabled. */
627 	if (!(mtrrdef & MTRR_DEF_ENABLE)) {
628 		if (bootverbose)
629 			printf("CPU supports MTRRs but not enabled\n");
630 		return;
631 	}
632 	nmdesc = mtrrcap & MTRR_CAP_VCNT;
633 	if (bootverbose)
634 		printf("Pentium Pro MTRR support enabled\n");
635 
636 	/*
637 	 * Determine the size of the PhysMask and PhysBase fields in
638 	 * the variable range MTRRs.
639 	 */
640 	mtrr_physmask = (((uint64_t)1 << cpu_maxphyaddr) - 1) &
641 	    ~(uint64_t)0xfff;
642 
643 	/* If fixed MTRRs supported and enabled. */
644 	if ((mtrrcap & MTRR_CAP_FIXED) && (mtrrdef & MTRR_DEF_FIXED_ENABLE)) {
645 		sc->mr_cap = MR686_FIXMTRR;
646 		nmdesc += MTRR_N64K + MTRR_N16K + MTRR_N4K;
647 	}
648 
649 	sc->mr_desc = malloc(nmdesc * sizeof(struct mem_range_desc), M_MEMDESC,
650 	    M_WAITOK | M_ZERO);
651 	sc->mr_ndesc = nmdesc;
652 
653 	mrd = sc->mr_desc;
654 
655 	/* Populate the fixed MTRR entries' base/length. */
656 	if (sc->mr_cap & MR686_FIXMTRR) {
657 		for (i = 0; i < MTRR_N64K; i++, mrd++) {
658 			mrd->mr_base = i * 0x10000;
659 			mrd->mr_len = 0x10000;
660 			mrd->mr_flags = MDF_FIXBASE | MDF_FIXLEN |
661 			    MDF_FIXACTIVE;
662 		}
663 		for (i = 0; i < MTRR_N16K; i++, mrd++) {
664 			mrd->mr_base = i * 0x4000 + 0x80000;
665 			mrd->mr_len = 0x4000;
666 			mrd->mr_flags = MDF_FIXBASE | MDF_FIXLEN |
667 			    MDF_FIXACTIVE;
668 		}
669 		for (i = 0; i < MTRR_N4K; i++, mrd++) {
670 			mrd->mr_base = i * 0x1000 + 0xc0000;
671 			mrd->mr_len = 0x1000;
672 			mrd->mr_flags = MDF_FIXBASE | MDF_FIXLEN |
673 			    MDF_FIXACTIVE;
674 		}
675 	}
676 
677 	/*
678 	 * Get current settings, anything set now is considered to
679 	 * have been set by the firmware. (XXX has something already
680 	 * played here?)
681 	 */
682 	x86_mrfetch(sc);
683 	mrd = sc->mr_desc;
684 	for (i = 0; i < sc->mr_ndesc; i++, mrd++) {
685 		if (mrd->mr_flags & MDF_ACTIVE)
686 			mrd->mr_flags |= MDF_FIRMWARE;
687 	}
688 
689 	x86_mr_split_dmap(sc);
690 }
691 
692 /*
693  * Initialise MTRRs on an AP after the BSP has run the init code.
694  */
695 static void
696 x86_mrAPinit(struct mem_range_softc *sc)
697 {
698 
699 	x86_mrstoreone(sc);
700 	wrmsr(MSR_MTRRdefType, mtrrdef);
701 }
702 
703 /*
704  * Re-initialise running CPU(s) MTRRs to match the ranges in the descriptor
705  * list.
706  *
707  * Must be called with interrupts enabled.
708  */
709 static void
710 x86_mrreinit(struct mem_range_softc *sc)
711 {
712 
713 	smp_rendezvous(NULL, (void (*)(void *))x86_mrAPinit, NULL, sc);
714 }
715 
716 static void
717 x86_mem_drvinit(void *unused)
718 {
719 
720 	if (mtrrs_disabled)
721 		return;
722 	if (!(cpu_feature & CPUID_MTRR))
723 		return;
724 	mem_range_softc.mr_op = &x86_mrops;
725 	x86_mrinit(&mem_range_softc);
726 }
727 SYSINIT(x86memdev, SI_SUB_CPU, SI_ORDER_ANY, x86_mem_drvinit, NULL);
728