xref: /freebsd/sys/powerpc/aim/moea64_native.c (revision 595e514d0df2bac5b813d35f83e32875dbf16a83)
1 /*-
2  * Copyright (c) 2001 The NetBSD Foundation, Inc.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to The NetBSD Foundation
6  * by Matt Thomas <matt@3am-software.com> of Allegro Networks, Inc.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
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  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *        This product includes software developed by the NetBSD
19  *        Foundation, Inc. and its contributors.
20  * 4. Neither the name of The NetBSD Foundation nor the names of its
21  *    contributors may be used to endorse or promote products derived
22  *    from this software without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
27  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
28  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 /*-
37  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
38  * Copyright (C) 1995, 1996 TooLs GmbH.
39  * All rights reserved.
40  *
41  * Redistribution and use in source and binary forms, with or without
42  * modification, are permitted provided that the following conditions
43  * are met:
44  * 1. Redistributions of source code must retain the above copyright
45  *    notice, this list of conditions and the following disclaimer.
46  * 2. Redistributions in binary form must reproduce the above copyright
47  *    notice, this list of conditions and the following disclaimer in the
48  *    documentation and/or other materials provided with the distribution.
49  * 3. All advertising materials mentioning features or use of this software
50  *    must display the following acknowledgement:
51  *	This product includes software developed by TooLs GmbH.
52  * 4. The name of TooLs GmbH may not be used to endorse or promote products
53  *    derived from this software without specific prior written permission.
54  *
55  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
56  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
57  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
58  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
59  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
60  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
61  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
62  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
63  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
64  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
65  *
66  * $NetBSD: pmap.c,v 1.28 2000/03/26 20:42:36 kleink Exp $
67  */
68 /*-
69  * Copyright (C) 2001 Benno Rice.
70  * All rights reserved.
71  *
72  * Redistribution and use in source and binary forms, with or without
73  * modification, are permitted provided that the following conditions
74  * are met:
75  * 1. Redistributions of source code must retain the above copyright
76  *    notice, this list of conditions and the following disclaimer.
77  * 2. Redistributions in binary form must reproduce the above copyright
78  *    notice, this list of conditions and the following disclaimer in the
79  *    documentation and/or other materials provided with the distribution.
80  *
81  * THIS SOFTWARE IS PROVIDED BY Benno Rice ``AS IS'' AND ANY EXPRESS OR
82  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
83  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
84  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
85  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
86  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
87  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
88  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
89  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
90  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
91  */
92 
93 #include <sys/cdefs.h>
94 __FBSDID("$FreeBSD$");
95 
96 /*
97  * Native 64-bit page table operations for running without a hypervisor.
98  */
99 
100 #include <sys/param.h>
101 #include <sys/kernel.h>
102 #include <sys/ktr.h>
103 #include <sys/lock.h>
104 #include <sys/mutex.h>
105 #include <sys/proc.h>
106 #include <sys/sched.h>
107 #include <sys/sysctl.h>
108 #include <sys/systm.h>
109 
110 #include <sys/kdb.h>
111 
112 #include <vm/vm.h>
113 #include <vm/vm_param.h>
114 #include <vm/vm_kern.h>
115 #include <vm/vm_page.h>
116 #include <vm/vm_map.h>
117 #include <vm/vm_object.h>
118 #include <vm/vm_extern.h>
119 #include <vm/vm_pageout.h>
120 
121 #include <machine/md_var.h>
122 #include <machine/mmuvar.h>
123 
124 #include "mmu_oea64.h"
125 #include "mmu_if.h"
126 #include "moea64_if.h"
127 
128 #define	PTESYNC()	__asm __volatile("ptesync");
129 #define	TLBSYNC()	__asm __volatile("tlbsync; ptesync");
130 #define	SYNC()		__asm __volatile("sync");
131 #define	EIEIO()		__asm __volatile("eieio");
132 
133 #define	VSID_HASH_MASK	0x0000007fffffffffULL
134 
135 static __inline void
136 TLBIE(uint64_t vpn) {
137 #ifndef __powerpc64__
138 	register_t vpn_hi, vpn_lo;
139 	register_t msr;
140 	register_t scratch, intr;
141 #endif
142 
143 	static volatile u_int tlbie_lock = 0;
144 
145 	vpn <<= ADDR_PIDX_SHFT;
146 	vpn &= ~(0xffffULL << 48);
147 
148 	/* Hobo spinlock: we need stronger guarantees than mutexes provide */
149 	while (!atomic_cmpset_int(&tlbie_lock, 0, 1));
150 	isync(); /* Flush instruction queue once lock acquired */
151 
152 #ifdef __powerpc64__
153 	__asm __volatile("tlbie %0" :: "r"(vpn) : "memory");
154 	__asm __volatile("eieio; tlbsync; ptesync" ::: "memory");
155 #else
156 	vpn_hi = (uint32_t)(vpn >> 32);
157 	vpn_lo = (uint32_t)vpn;
158 
159 	intr = intr_disable();
160 	__asm __volatile("\
161 	    mfmsr %0; \
162 	    mr %1, %0; \
163 	    insrdi %1,%5,1,0; \
164 	    mtmsrd %1; isync; \
165 	    \
166 	    sld %1,%2,%4; \
167 	    or %1,%1,%3; \
168 	    tlbie %1; \
169 	    \
170 	    mtmsrd %0; isync; \
171 	    eieio; \
172 	    tlbsync; \
173 	    ptesync;"
174 	: "=r"(msr), "=r"(scratch) : "r"(vpn_hi), "r"(vpn_lo), "r"(32), "r"(1)
175 	    : "memory");
176 	intr_restore(intr);
177 #endif
178 
179 	/* No barriers or special ops -- taken care of by ptesync above */
180 	tlbie_lock = 0;
181 }
182 
183 #define DISABLE_TRANS(msr)	msr = mfmsr(); mtmsr(msr & ~PSL_DR)
184 #define ENABLE_TRANS(msr)	mtmsr(msr)
185 
186 /*
187  * PTEG data.
188  */
189 static struct	lpteg *moea64_pteg_table;
190 
191 /*
192  * PTE calls.
193  */
194 static int	moea64_pte_insert_native(mmu_t, u_int, struct lpte *);
195 static uintptr_t moea64_pvo_to_pte_native(mmu_t, const struct pvo_entry *);
196 static void	moea64_pte_synch_native(mmu_t, uintptr_t pt,
197 		    struct lpte *pvo_pt);
198 static void	moea64_pte_clear_native(mmu_t, uintptr_t pt,
199 		    struct lpte *pvo_pt, uint64_t vpn, uint64_t ptebit);
200 static void	moea64_pte_change_native(mmu_t, uintptr_t pt,
201 		    struct lpte *pvo_pt, uint64_t vpn);
202 static void	moea64_pte_unset_native(mmu_t mmu, uintptr_t pt,
203 		    struct lpte *pvo_pt, uint64_t vpn);
204 
205 /*
206  * Utility routines.
207  */
208 static void		moea64_bootstrap_native(mmu_t mmup,
209 			    vm_offset_t kernelstart, vm_offset_t kernelend);
210 static void		moea64_cpu_bootstrap_native(mmu_t, int ap);
211 static void		tlbia(void);
212 
213 static mmu_method_t moea64_native_methods[] = {
214 	/* Internal interfaces */
215 	MMUMETHOD(mmu_bootstrap,	moea64_bootstrap_native),
216 	MMUMETHOD(mmu_cpu_bootstrap,	moea64_cpu_bootstrap_native),
217 
218 	MMUMETHOD(moea64_pte_synch,	moea64_pte_synch_native),
219 	MMUMETHOD(moea64_pte_clear,	moea64_pte_clear_native),
220 	MMUMETHOD(moea64_pte_unset,	moea64_pte_unset_native),
221 	MMUMETHOD(moea64_pte_change,	moea64_pte_change_native),
222 	MMUMETHOD(moea64_pte_insert,	moea64_pte_insert_native),
223 	MMUMETHOD(moea64_pvo_to_pte,	moea64_pvo_to_pte_native),
224 
225 	{ 0, 0 }
226 };
227 
228 MMU_DEF_INHERIT(oea64_mmu_native, MMU_TYPE_G5, moea64_native_methods,
229     0, oea64_mmu);
230 
231 static __inline u_int
232 va_to_pteg(uint64_t vsid, vm_offset_t addr, int large)
233 {
234 	uint64_t hash;
235 	int shift;
236 
237 	shift = large ? moea64_large_page_shift : ADDR_PIDX_SHFT;
238 	hash = (vsid & VSID_HASH_MASK) ^ (((uint64_t)addr & ADDR_PIDX) >>
239 	    shift);
240 	return (hash & moea64_pteg_mask);
241 }
242 
243 static void
244 moea64_pte_synch_native(mmu_t mmu, uintptr_t pt_cookie, struct lpte *pvo_pt)
245 {
246 	struct lpte *pt = (struct lpte *)pt_cookie;
247 
248 	pvo_pt->pte_lo |= pt->pte_lo & (LPTE_REF | LPTE_CHG);
249 }
250 
251 static void
252 moea64_pte_clear_native(mmu_t mmu, uintptr_t pt_cookie, struct lpte *pvo_pt,
253     uint64_t vpn, uint64_t ptebit)
254 {
255 	struct lpte *pt = (struct lpte *)pt_cookie;
256 
257 	/*
258 	 * As shown in Section 7.6.3.2.3
259 	 */
260 	pt->pte_lo &= ~ptebit;
261 	critical_enter();
262 	TLBIE(vpn);
263 	critical_exit();
264 }
265 
266 static void
267 moea64_pte_set_native(struct lpte *pt, struct lpte *pvo_pt)
268 {
269 
270 	pvo_pt->pte_hi |= LPTE_VALID;
271 
272 	/*
273 	 * Update the PTE as defined in section 7.6.3.1.
274 	 * Note that the REF/CHG bits are from pvo_pt and thus should have
275 	 * been saved so this routine can restore them (if desired).
276 	 */
277 	pt->pte_lo = pvo_pt->pte_lo;
278 	EIEIO();
279 	pt->pte_hi = pvo_pt->pte_hi;
280 	PTESYNC();
281 
282 	/* Keep statistics for unlocked pages */
283 	if (!(pvo_pt->pte_hi & LPTE_LOCKED))
284 		moea64_pte_valid++;
285 }
286 
287 static void
288 moea64_pte_unset_native(mmu_t mmu, uintptr_t pt_cookie, struct lpte *pvo_pt,
289     uint64_t vpn)
290 {
291 	struct lpte *pt = (struct lpte *)pt_cookie;
292 
293 	/*
294 	 * Invalidate the pte.
295 	 */
296 	isync();
297 	critical_enter();
298 	pvo_pt->pte_hi &= ~LPTE_VALID;
299 	pt->pte_hi &= ~LPTE_VALID;
300 	PTESYNC();
301 	TLBIE(vpn);
302 	critical_exit();
303 
304 	/*
305 	 * Save the reg & chg bits.
306 	 */
307 	moea64_pte_synch_native(mmu, pt_cookie, pvo_pt);
308 
309 	/* Keep statistics for unlocked pages */
310 	if (!(pvo_pt->pte_hi & LPTE_LOCKED))
311 		moea64_pte_valid--;
312 }
313 
314 static void
315 moea64_pte_change_native(mmu_t mmu, uintptr_t pt, struct lpte *pvo_pt,
316     uint64_t vpn)
317 {
318 
319 	/*
320 	 * Invalidate the PTE
321 	 */
322 	moea64_pte_unset_native(mmu, pt, pvo_pt, vpn);
323 	moea64_pte_set_native((struct lpte *)pt, pvo_pt);
324 }
325 
326 static void
327 moea64_cpu_bootstrap_native(mmu_t mmup, int ap)
328 {
329 	int i = 0;
330 	#ifdef __powerpc64__
331 	struct slb *slb = PCPU_GET(slb);
332 	register_t seg0;
333 	#endif
334 
335 	/*
336 	 * Initialize segment registers and MMU
337 	 */
338 
339 	mtmsr(mfmsr() & ~PSL_DR & ~PSL_IR);
340 
341 	/*
342 	 * Install kernel SLB entries
343 	 */
344 
345 	#ifdef __powerpc64__
346 		__asm __volatile ("slbia");
347 		__asm __volatile ("slbmfee %0,%1; slbie %0;" : "=r"(seg0) :
348 		    "r"(0));
349 
350 		for (i = 0; i < 64; i++) {
351 			if (!(slb[i].slbe & SLBE_VALID))
352 				continue;
353 
354 			__asm __volatile ("slbmte %0, %1" ::
355 			    "r"(slb[i].slbv), "r"(slb[i].slbe));
356 		}
357 	#else
358 		for (i = 0; i < 16; i++)
359 			mtsrin(i << ADDR_SR_SHFT, kernel_pmap->pm_sr[i]);
360 	#endif
361 
362 	/*
363 	 * Install page table
364 	 */
365 
366 	__asm __volatile ("ptesync; mtsdr1 %0; isync"
367 	    :: "r"((uintptr_t)moea64_pteg_table
368 		     | (uintptr_t)(flsl(moea64_pteg_mask >> 11))));
369 	tlbia();
370 }
371 
372 static void
373 moea64_bootstrap_native(mmu_t mmup, vm_offset_t kernelstart,
374     vm_offset_t kernelend)
375 {
376 	vm_size_t	size;
377 	vm_offset_t	off;
378 	vm_paddr_t	pa;
379 	register_t	msr;
380 
381 	moea64_early_bootstrap(mmup, kernelstart, kernelend);
382 
383 	/*
384 	 * Allocate PTEG table.
385 	 */
386 
387 	size = moea64_pteg_count * sizeof(struct lpteg);
388 	CTR2(KTR_PMAP, "moea64_bootstrap: %d PTEGs, %d bytes",
389 	    moea64_pteg_count, size);
390 
391 	/*
392 	 * We now need to allocate memory. This memory, to be allocated,
393 	 * has to reside in a page table. The page table we are about to
394 	 * allocate. We don't have BAT. So drop to data real mode for a minute
395 	 * as a measure of last resort. We do this a couple times.
396 	 */
397 
398 	moea64_pteg_table = (struct lpteg *)moea64_bootstrap_alloc(size, size);
399 	DISABLE_TRANS(msr);
400 	bzero((void *)moea64_pteg_table, moea64_pteg_count * sizeof(struct lpteg));
401 	ENABLE_TRANS(msr);
402 
403 	CTR1(KTR_PMAP, "moea64_bootstrap: PTEG table at %p", moea64_pteg_table);
404 
405 	moea64_mid_bootstrap(mmup, kernelstart, kernelend);
406 
407 	/*
408 	 * Add a mapping for the page table itself if there is no direct map.
409 	 */
410 	if (!hw_direct_map) {
411 		size = moea64_pteg_count * sizeof(struct lpteg);
412 		off = (vm_offset_t)(moea64_pteg_table);
413 		DISABLE_TRANS(msr);
414 		for (pa = off; pa < off + size; pa += PAGE_SIZE)
415 			pmap_kenter(pa, pa);
416 		ENABLE_TRANS(msr);
417 	}
418 
419 	/* Bring up virtual memory */
420 	moea64_late_bootstrap(mmup, kernelstart, kernelend);
421 }
422 
423 static void
424 tlbia(void)
425 {
426 	vm_offset_t i;
427 	#ifndef __powerpc64__
428 	register_t msr, scratch;
429 	#endif
430 
431 	TLBSYNC();
432 
433 	for (i = 0; i < 0xFF000; i += 0x00001000) {
434 		#ifdef __powerpc64__
435 		__asm __volatile("tlbiel %0" :: "r"(i));
436 		#else
437 		__asm __volatile("\
438 		    mfmsr %0; \
439 		    mr %1, %0; \
440 		    insrdi %1,%3,1,0; \
441 		    mtmsrd %1; \
442 		    isync; \
443 		    \
444 		    tlbiel %2; \
445 		    \
446 		    mtmsrd %0; \
447 		    isync;"
448 		: "=r"(msr), "=r"(scratch) : "r"(i), "r"(1));
449 		#endif
450 	}
451 
452 	EIEIO();
453 	TLBSYNC();
454 }
455 
456 static uintptr_t
457 moea64_pvo_to_pte_native(mmu_t mmu, const struct pvo_entry *pvo)
458 {
459 	struct lpte 	*pt;
460 	int		pteidx, ptegidx;
461 	uint64_t	vsid;
462 
463 	/* If the PTEG index is not set, then there is no page table entry */
464 	if (!PVO_PTEGIDX_ISSET(pvo))
465 		return (-1);
466 
467 	/*
468 	 * Calculate the ptegidx
469 	 */
470 	vsid = PVO_VSID(pvo);
471 	ptegidx = va_to_pteg(vsid, PVO_VADDR(pvo),
472 	    pvo->pvo_vaddr & PVO_LARGE);
473 
474 	/*
475 	 * We can find the actual pte entry without searching by grabbing
476 	 * the PTEG index from 3 unused bits in pvo_vaddr and by
477 	 * noticing the HID bit.
478 	 */
479 	if (pvo->pvo_pte.lpte.pte_hi & LPTE_HID)
480 		ptegidx ^= moea64_pteg_mask;
481 
482 	pteidx = (ptegidx << 3) | PVO_PTEGIDX_GET(pvo);
483 
484 	if ((pvo->pvo_pte.lpte.pte_hi & LPTE_VALID) &&
485 	    !PVO_PTEGIDX_ISSET(pvo)) {
486 		panic("moea64_pvo_to_pte: pvo %p has valid pte in pvo but no "
487 		    "valid pte index", pvo);
488 	}
489 
490 	if ((pvo->pvo_pte.lpte.pte_hi & LPTE_VALID) == 0 &&
491 	    PVO_PTEGIDX_ISSET(pvo)) {
492 		panic("moea64_pvo_to_pte: pvo %p has valid pte index in pvo "
493 		    "pvo but no valid pte", pvo);
494 	}
495 
496 	pt = &moea64_pteg_table[pteidx >> 3].pt[pteidx & 7];
497 	if ((pt->pte_hi ^ (pvo->pvo_pte.lpte.pte_hi & ~LPTE_VALID)) ==
498 	    LPTE_VALID) {
499 		if ((pvo->pvo_pte.lpte.pte_hi & LPTE_VALID) == 0) {
500 			panic("moea64_pvo_to_pte: pvo %p has valid pte in "
501 			    "moea64_pteg_table %p but invalid in pvo", pvo, pt);
502 		}
503 
504 		if (((pt->pte_lo ^ pvo->pvo_pte.lpte.pte_lo) &
505 		    ~(LPTE_M|LPTE_CHG|LPTE_REF)) != 0) {
506 			panic("moea64_pvo_to_pte: pvo %p pte does not match "
507 			    "pte %p in moea64_pteg_table difference is %#x",
508 			    pvo, pt,
509 			    (uint32_t)(pt->pte_lo ^ pvo->pvo_pte.lpte.pte_lo));
510 		}
511 
512 		return ((uintptr_t)pt);
513 	}
514 
515 	if (pvo->pvo_pte.lpte.pte_hi & LPTE_VALID) {
516 		panic("moea64_pvo_to_pte: pvo %p has invalid pte %p in "
517 		    "moea64_pteg_table but valid in pvo", pvo, pt);
518 	}
519 
520 	return (-1);
521 }
522 
523 static __inline int
524 moea64_pte_spillable_ident(u_int ptegidx)
525 {
526 	struct	lpte *pt;
527 	int	i, j, k;
528 
529 	/* Start at a random slot */
530 	i = mftb() % 8;
531 	k = -1;
532 	for (j = 0; j < 8; j++) {
533 		pt = &moea64_pteg_table[ptegidx].pt[(i + j) % 8];
534 		if (pt->pte_hi & (LPTE_LOCKED | LPTE_WIRED))
535 			continue;
536 
537 		/* This is a candidate, so remember it */
538 		k = (i + j) % 8;
539 
540 		/* Try to get a page that has not been used lately */
541 		if (!(pt->pte_lo & LPTE_REF))
542 			return (k);
543 	}
544 
545 	return (k);
546 }
547 
548 static int
549 moea64_pte_insert_native(mmu_t mmu, u_int ptegidx, struct lpte *pvo_pt)
550 {
551 	struct	lpte *pt;
552 	struct	pvo_entry *pvo;
553 	u_int	pteg_bktidx;
554 	int	i;
555 
556 	/*
557 	 * First try primary hash.
558 	 */
559 	pteg_bktidx = ptegidx;
560 	for (pt = moea64_pteg_table[pteg_bktidx].pt, i = 0; i < 8; i++, pt++) {
561 		if ((pt->pte_hi & (LPTE_VALID | LPTE_LOCKED)) == 0) {
562 			pvo_pt->pte_hi &= ~LPTE_HID;
563 			moea64_pte_set_native(pt, pvo_pt);
564 			return (i);
565 		}
566 	}
567 
568 	/*
569 	 * Now try secondary hash.
570 	 */
571 	pteg_bktidx ^= moea64_pteg_mask;
572 	for (pt = moea64_pteg_table[pteg_bktidx].pt, i = 0; i < 8; i++, pt++) {
573 		if ((pt->pte_hi & (LPTE_VALID | LPTE_LOCKED)) == 0) {
574 			pvo_pt->pte_hi |= LPTE_HID;
575 			moea64_pte_set_native(pt, pvo_pt);
576 			return (i);
577 		}
578 	}
579 
580 	/*
581 	 * Out of luck. Find a PTE to sacrifice.
582 	 */
583 	pteg_bktidx = ptegidx;
584 	i = moea64_pte_spillable_ident(pteg_bktidx);
585 	if (i < 0) {
586 		pteg_bktidx ^= moea64_pteg_mask;
587 		i = moea64_pte_spillable_ident(pteg_bktidx);
588 	}
589 
590 	if (i < 0) {
591 		/* No freeable slots in either PTEG? We're hosed. */
592 		panic("moea64_pte_insert: overflow");
593 		return (-1);
594 	}
595 
596 	if (pteg_bktidx == ptegidx)
597 		pvo_pt->pte_hi &= ~LPTE_HID;
598 	else
599 		pvo_pt->pte_hi |= LPTE_HID;
600 
601 	/*
602 	 * Synchronize the sacrifice PTE with its PVO, then mark both
603 	 * invalid. The PVO will be reused when/if the VM system comes
604 	 * here after a fault.
605 	 */
606 	pt = &moea64_pteg_table[pteg_bktidx].pt[i];
607 
608 	if (pt->pte_hi & LPTE_HID)
609 		pteg_bktidx ^= moea64_pteg_mask; /* PTEs indexed by primary */
610 
611 	LIST_FOREACH(pvo, &moea64_pvo_table[pteg_bktidx], pvo_olink) {
612 		if (pvo->pvo_pte.lpte.pte_hi == pt->pte_hi) {
613 			KASSERT(pvo->pvo_pte.lpte.pte_hi & LPTE_VALID,
614 			    ("Invalid PVO for valid PTE!"));
615 			moea64_pte_unset_native(mmu, (uintptr_t)pt,
616 			    &pvo->pvo_pte.lpte, pvo->pvo_vpn);
617 			PVO_PTEGIDX_CLR(pvo);
618 			moea64_pte_overflow++;
619 			break;
620 		}
621 	}
622 
623 	KASSERT(pvo->pvo_pte.lpte.pte_hi == pt->pte_hi,
624 	   ("Unable to find PVO for spilled PTE"));
625 
626 	/*
627 	 * Set the new PTE.
628 	 */
629 	moea64_pte_set_native(pt, pvo_pt);
630 
631 	return (i);
632 }
633 
634