xref: /netbsd-src/sys/arch/mac68k/mac68k/pmap_bootstrap.c (revision 88fcb00c0357f2d7c1774f86a352637bfda96184)
1 /*	$NetBSD: pmap_bootstrap.c,v 1.92 2011/01/02 18:48:06 tsutsui Exp $	*/
2 
3 /*
4  * Copyright (c) 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * the Systems Programming Group of the University of Utah Computer
9  * Science Department.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)pmap_bootstrap.c	8.1 (Berkeley) 6/10/93
36  */
37 
38 #include <sys/cdefs.h>
39 __KERNEL_RCSID(0, "$NetBSD: pmap_bootstrap.c,v 1.92 2011/01/02 18:48:06 tsutsui Exp $");
40 
41 #include "opt_ddb.h"
42 #include "opt_kgdb.h"
43 #include "opt_m68k_arch.h"
44 
45 #include "zsc.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/reboot.h>
50 
51 #include <uvm/uvm_extern.h>
52 
53 #include <machine/cpu.h>
54 #include <machine/pte.h>
55 #include <machine/vmparam.h>
56 #include <machine/pmap.h>
57 #include <machine/autoconf.h>
58 #include <machine/video.h>
59 
60 #include <mac68k/mac68k/macrom.h>
61 
62 #define PA2VA(v, t)	(t)((u_int)(v) - firstpa)
63 
64 extern char *etext;
65 extern char *extiobase;
66 
67 extern paddr_t avail_start, avail_end;
68 
69 #if NZSC > 0
70 extern	int	zsinited;
71 #endif
72 
73 /*
74  * These are used to map the RAM:
75  */
76 int	numranges;	/* = 0 == don't use the ranges */
77 u_long	low[8];
78 u_long	high[8];
79 u_long	maxaddr;	/* PA of the last physical page */
80 int	vidlen;
81 #define VIDMAPSIZE	btoc(vidlen)
82 static vaddr_t	newvideoaddr;
83 
84 extern void *	ROMBase;
85 
86 /*
87  * Special purpose kernel virtual addresses, used for mapping
88  * physical pages for a variety of temporary or permanent purposes:
89  *
90  *	CADDR1, CADDR2:	pmap zero/copy operations
91  *	vmmap:		/dev/mem, crash dumps, parity error checking
92  *	msgbufaddr:	kernel message buffer
93  */
94 void *CADDR1, *CADDR2;
95 char *vmmap;
96 void *msgbufaddr;
97 
98 void pmap_bootstrap(paddr_t, paddr_t);
99 void bootstrap_mac68k(int);
100 
101 /*
102  * Bootstrap the VM system.
103  *
104  * This is called with the MMU either on or off.  If it's on, we assume
105  * that it's mapped with the same PA <=> LA mapping that we eventually
106  * want.  The page sizes and the protections will be wrong, anyway.
107  *
108  * nextpa is the first address following the loaded kernel.  On a IIsi
109  * on 12 May 1996, that was 0xf9000 beyond firstpa.
110  */
111 void
112 pmap_bootstrap(paddr_t nextpa, paddr_t firstpa)
113 {
114 	paddr_t lwp0upa, kstpa, kptmpa, kptpa;
115 	u_int nptpages, kstsize;
116 	paddr_t avail_next;
117 	int avail_remaining;
118 	int avail_range;
119 	int i;
120 	st_entry_t protoste, *ste, *este;
121 	pt_entry_t protopte, *pte, *epte;
122 	u_int stfree = 0;	/* XXX: gcc -Wuninitialized */
123 	extern char start[];
124 
125 	vidlen = m68k_round_page(mac68k_video.mv_height *
126 	    mac68k_video.mv_stride + m68k_page_offset(mac68k_video.mv_phys));
127 
128 	/*
129 	 * Calculate important physical addresses:
130 	 *
131 	 *	lwp0upa		lwp0 u-area		UPAGES pages
132 	 *
133 	 *	kstpa		kernel segment table	1 page (!040)
134 	 *						N pages (040)
135 	 *
136 	 *	kptmpa		kernel PT map		1 page
137 	 *
138 	 *	kptpa		statically allocated
139 	 *			kernel PT pages		Sysptsize+ pages
140 	 *
141 	 * [ Sysptsize is the number of pages of PT, and IIOMAPSIZE and
142 	 *   NBMAPSIZE are the number of PTEs, hence we need to round
143 	 *   the total to a page boundary with IO maps at the end. ]
144 	 *
145 	 */
146 	lwp0upa = nextpa;
147 	nextpa += USPACE;
148 	if (mmutype == MMU_68040)
149 		kstsize = MAXKL2SIZE / (NPTEPG/SG4_LEV2SIZE);
150 	else
151 		kstsize = 1;
152 	kstpa = nextpa;
153 	nextpa += kstsize * PAGE_SIZE;
154 	kptmpa = nextpa;
155 	nextpa += PAGE_SIZE;
156 	kptpa = nextpa;
157 	nptpages = Sysptsize +
158 		(IIOMAPSIZE + ROMMAPSIZE + VIDMAPSIZE + NPTEPG - 1) / NPTEPG;
159 	nextpa += nptpages * PAGE_SIZE;
160 
161 	for (i = 0; i < numranges; i++)
162 		if (low[i] <= firstpa && firstpa < high[i])
163 			break;
164 	if (i >= numranges || nextpa > high[i]) {
165 		if (mac68k_machine.do_graybars) {
166 			printf("Failure in NetBSD boot; ");
167 			if (i < numranges)
168 				printf("nextpa=0x%lx, high[%d]=0x%lx.\n",
169 				    nextpa, i, high[i]);
170 			else
171 				printf("can't find kernel RAM segment.\n");
172 			printf("You're hosed!  Try booting with 32-bit ");
173 			printf("addressing enabled in the memory control ");
174 			printf("panel.\n");
175 			printf("Older machines may need Mode32 to get that ");
176 			printf("option.\n");
177 		}
178 		panic("Cannot work with the current memory mappings.");
179 	}
180 
181 	/*
182 	 * Initialize segment table and kernel page table map.
183 	 *
184 	 * On 68030s and earlier MMUs the two are identical except for
185 	 * the valid bits so both are initialized with essentially the
186 	 * same values.  On the 68040, which has a mandatory 3-level
187 	 * structure, the segment table holds the level 1 table and part
188 	 * (or all) of the level 2 table and hence is considerably
189 	 * different.  Here the first level consists of 128 descriptors
190 	 * (512 bytes) each mapping 32mb of address space.  Each of these
191 	 * points to blocks of 128 second level descriptors (512 bytes)
192 	 * each mapping 256kb.  Note that there may be additional "segment
193 	 * table" pages depending on how large MAXKL2SIZE is.
194 	 *
195 	 * Portions of the last segment of KVA space (0xFFC00000 -
196 	 * 0xFFFFFFFF) are mapped for the kernel page tables.
197 	 *
198 	 * XXX cramming two levels of mapping into the single "segment"
199 	 * table on the 68040 is intended as a temporary hack to get things
200 	 * working.  The 224mb of address space that this allows will most
201 	 * likely be insufficient in the future (at least for the kernel).
202 	 */
203 	if (mmutype == MMU_68040) {
204 		int nl1desc, nl2desc;
205 
206 		/*
207 		 * First invalidate the entire "segment table" pages
208 		 * (levels 1 and 2 have the same "invalid" value).
209 		 */
210 		ste = PA2VA(kstpa, st_entry_t *);
211 		este = &ste[kstsize * NPTEPG];
212 		while (ste < este)
213 			*ste++ = SG_NV;
214 		/*
215 		 * Initialize level 2 descriptors (which immediately
216 		 * follow the level 1 table).  We need:
217 		 *	NPTEPG / SG4_LEV3SIZE
218 		 * level 2 descriptors to map each of the nptpages
219 		 * pages of PTEs.  Note that we set the "used" bit
220 		 * now to save the HW the expense of doing it.
221 		 */
222 		nl2desc = nptpages * (NPTEPG / SG4_LEV3SIZE);
223 		ste = PA2VA(kstpa, st_entry_t *);
224 		ste = &ste[SG4_LEV1SIZE];
225 		este = &ste[nl2desc];
226 		protoste = kptpa | SG_U | SG_RW | SG_V;
227 		while (ste < este) {
228 			*ste++ = protoste;
229 			protoste += (SG4_LEV3SIZE * sizeof(st_entry_t));
230 		}
231 		/*
232 		 * Initialize level 1 descriptors.  We need:
233 		 *	howmany(nl2desc, SG4_LEV2SIZE)
234 		 * level 1 descriptors to map the `nl2desc' level 2's.
235 		 */
236 		nl1desc = howmany(nl2desc, SG4_LEV2SIZE);
237 		ste = PA2VA(kstpa, u_int *);
238 		este = &ste[nl1desc];
239 		protoste = (paddr_t)&ste[SG4_LEV1SIZE] | SG_U | SG_RW | SG_V;
240 		while (ste < este) {
241 			*ste++ = protoste;
242 			protoste += (SG4_LEV2SIZE * sizeof(st_entry_t));
243 		}
244 		/*
245 		 * Initialize the final level 1 descriptor to map the next
246 		 * block of level 2 descriptors for Sysptmap.
247 		 */
248 		ste = PA2VA(kstpa, st_entry_t *);
249 		ste = &ste[SG4_LEV1SIZE - 1];
250 		*ste = protoste;
251 		/*
252 		 * Now initialize the final portion of that block of
253 		 * descriptors to map Sysmap.
254 		 */
255 		i = SG4_LEV1SIZE + (nl1desc * SG4_LEV2SIZE);
256 		ste = PA2VA(kstpa, st_entry_t *);
257 		ste = &ste[i + SG4_LEV2SIZE - (NPTEPG / SG4_LEV3SIZE)];
258 		este = &ste[NPTEPG / SG4_LEV3SIZE];
259 		protoste = kptmpa | SG_U | SG_RW | SG_V;
260 		while (ste < este) {
261 			*ste++ = protoste;
262 			protoste += (SG4_LEV3SIZE * sizeof(st_entry_t));
263 		}
264 		/*
265 		 * Calculate the free level 2 descriptor mask
266 		 * noting that we have used:
267 		 *	0:		level 1 table
268 		 *	1 to nl1desc:	map page tables
269 		 *	nl1desc + 1:	maps kptmpa and last-page page table
270 		 */
271 		/* mark an entry for level 1 table */
272 		stfree = ~l2tobm(0);
273 		/* mark entries for map page tables */
274 		for (i = 1; i <= nl1desc; i++)
275 			stfree &= ~l2tobm(i);
276 		/* mark an entry for kptmpa and lkptpa */
277 		stfree &= ~l2tobm(i);
278 		/* mark entries not available */
279 		for (i = MAXKL2SIZE; i < sizeof(stfree) * NBBY; i++)
280 			stfree &= ~l2tobm(i);
281 
282 		/*
283 		 * Initialize Sysptmap
284 		 */
285 		pte = PA2VA(kptmpa, pt_entry_t *);
286 		epte = &pte[nptpages];
287 		protopte = kptpa | PG_RW | PG_CI | PG_V;
288 		while (pte < epte) {
289 			*pte++ = protopte;
290 			protopte += PAGE_SIZE;
291 		}
292 		/*
293 		 * Invalidate all remaining entries.
294 		 */
295 		epte = PA2VA(kptmpa, pt_entry_t *);
296 		epte = &epte[TIB_SIZE];
297 		while (pte < epte) {
298 			*pte++ = PG_NV;
299 		}
300 		/*
301 		 * Initialize the last one to point to Sysptmap.
302 		 */
303 		pte = PA2VA(kptmpa, pt_entry_t *);
304 		pte = &pte[SYSMAP_VA >> SEGSHIFT];
305 		*pte = kptmpa | PG_RW | PG_CI | PG_V;
306 	} else {
307 		/*
308 		 * Map the page table pages in both the HW segment table
309 		 * and the software Sysptmap.
310 		 */
311 		ste = PA2VA(kstpa, st_entry_t *);
312 		pte = PA2VA(kptmpa, pt_entry_t *);
313 		epte = &pte[nptpages];
314 		protoste = kptpa | SG_RW | SG_V;
315 		protopte = kptpa | PG_RW | PG_CI | PG_V;
316 		while (pte < epte) {
317 			*ste++ = protoste;
318 			*pte++ = protopte;
319 			protoste += PAGE_SIZE;
320 			protopte += PAGE_SIZE;
321 		}
322 		/*
323 		 * Invalidate all remaining entries in both.
324 		 */
325 		este = PA2VA(kstpa, st_entry_t *);
326 		este = &este[TIA_SIZE];
327 		while (ste < este)
328 			*ste++ = SG_NV;
329 		epte = PA2VA(kptmpa, pt_entry_t *);
330 		epte = &epte[TIB_SIZE];
331 		while (pte < epte)
332 			*pte++ = PG_NV;
333 		/*
334 		 * Initialize the last one to point to Sysptmap.
335 		 */
336 		ste = PA2VA(kstpa, st_entry_t *);
337 		ste = &ste[SYSMAP_VA >> SEGSHIFT];
338 		pte = PA2VA(kptmpa, pt_entry_t *);
339 		pte = &pte[SYSMAP_VA >> SEGSHIFT];
340 		*ste = kptmpa | SG_RW | SG_V;
341 		*pte = kptmpa | PG_RW | PG_CI | PG_V;
342 	}
343 
344 	/*
345 	 * Initialize kernel page table.
346 	 * Start by invalidating the `nptpages' that we have allocated.
347 	 */
348 	pte = PA2VA(kptpa, pt_entry_t *);
349 	epte = &pte[nptpages * NPTEPG];
350 	while (pte < epte)
351 		*pte++ = PG_NV;
352 	/*
353 	 * Validate PTEs for kernel text (RO).
354 	 * Pages up to "start" (vectors and Mac OS global variable space)
355 	 * must be writable for the ROM.
356 	 */
357 	pte = PA2VA(kptpa, pt_entry_t *);
358 	pte = &pte[m68k_btop(KERNBASE)];
359 	epte = &pte[m68k_btop(m68k_round_page(start))];
360 	protopte = firstpa | PG_RW | PG_V;
361 	while (pte < epte) {
362 		*pte++ = protopte;
363 		protopte += PAGE_SIZE;
364 	}
365 	epte = &pte[m68k_btop(m68k_trunc_page(&etext))];
366 	protopte = (protopte & ~PG_PROT) | PG_RO;
367 	while (pte < epte) {
368 		*pte++ = protopte;
369 		protopte += PAGE_SIZE;
370 	}
371 	/*
372 	 * Validate PTEs for kernel data/bss, dynamic data allocated
373 	 * by us so far (kstpa - firstpa bytes), and pages for lwp0
374 	 * u-area and page table allocated below (RW).
375 	 */
376 	epte = PA2VA(kptpa, pt_entry_t *);
377 	epte = &epte[m68k_btop(kstpa - firstpa)];
378 	protopte = (protopte & ~PG_PROT) | PG_RW;
379 	/*
380 	 * Enable copy-back caching of data pages
381 	 */
382 	if (mmutype == MMU_68040)
383 		protopte |= PG_CCB;
384 	while (pte < epte) {
385 		*pte++ = protopte;
386 		protopte += PAGE_SIZE;
387 	}
388 	/*
389 	 * Map the kernel segment table cache invalidated for 68040/68060.
390 	 * (for the 68040 not strictly necessary, but recommended by Motorola;
391 	 *  for the 68060 mandatory)
392 	 */
393 	epte = PA2VA(kptpa, pt_entry_t *);
394 	epte = &epte[m68k_btop(nextpa - firstpa)];
395 	protopte = (protopte & ~PG_PROT) | PG_RW;
396 	if (mmutype == MMU_68040) {
397 		protopte &= ~PG_CCB;
398 		protopte |= PG_CIN;
399 	}
400 	while (pte < epte) {
401 		*pte++ = protopte;
402 		protopte += PAGE_SIZE;
403 	}
404 
405 	/*
406 	 * Finally, validate the internal IO space PTEs (RW+CI).
407 	 */
408 
409 #define	PTE2VA(pte)	m68k_ptob(pte - PA2VA(kptpa, pt_entry_t *))
410 
411 	protopte = IOBase | PG_RW | PG_CI | PG_V;
412 	IOBase = PTE2VA(pte);
413 	epte = &pte[IIOMAPSIZE];
414 	while (pte < epte) {
415 		*pte++ = protopte;
416 		protopte += PAGE_SIZE;
417 	}
418 
419 	protopte = (pt_entry_t)ROMBase | PG_RO | PG_V;
420 	ROMBase = (void *)PTE2VA(pte);
421 	epte = &pte[ROMMAPSIZE];
422 	while (pte < epte) {
423 		*pte++ = protopte;
424 		protopte += PAGE_SIZE;
425 	}
426 
427 	if (vidlen) {
428 		protopte = m68k_trunc_page(mac68k_video.mv_phys) |
429 		    PG_RW | PG_V | PG_CI;
430 		newvideoaddr = PTE2VA(pte)
431 		    + m68k_page_offset(mac68k_video.mv_phys);
432 		epte = &pte[VIDMAPSIZE];
433 		while (pte < epte) {
434 			*pte++ = protopte;
435 			protopte += PAGE_SIZE;
436 		}
437 	}
438 	virtual_avail = PTE2VA(pte);
439 
440 	/*
441 	 * Calculate important exported kernel addresses and related values.
442 	 */
443 	/*
444 	 * Sysseg: base of kernel segment table
445 	 */
446 	Sysseg = PA2VA(kstpa, st_entry_t *);
447 	Sysseg_pa = PA2VA(kstpa, paddr_t);
448 #if defined(M68040)
449 	if (mmutype == MMU_68040)
450 		protostfree = stfree;
451 #endif
452 	/*
453 	 * Sysptmap: base of kernel page table map
454 	 */
455 	Sysptmap = PA2VA(kptmpa, pt_entry_t *);
456 	/*
457 	 * Sysmap: kernel page table (as mapped through Sysptmap)
458 	 * Allocated at the end of KVA space.
459 	 */
460 	Sysmap = (pt_entry_t *)SYSMAP_VA;
461 
462 	/*
463 	 * Remember the u-area address so it can be loaded in the lwp0
464 	 * via uvm_lwp_setuarea() later in pmap_bootstrap_finalize().
465 	 */
466 	lwp0uarea = PA2VA(lwp0upa, vaddr_t);
467 
468 	/*
469 	 * VM data structures are now initialized, set up data for
470 	 * the pmap module.
471 	 *
472 	 * Note about avail_end: msgbuf is initialized just after
473 	 * avail_end in machdep.c.  Since the last page is used
474 	 * for rebooting the system (code is copied there and
475 	 * excution continues from copied code before the MMU
476 	 * is disabled), the msgbuf will get trounced between
477 	 * reboots if it's placed in the last physical page.
478 	 * To work around this, we move avail_end back one more
479 	 * page so the msgbuf can be preserved.
480 	 */
481 	avail_next = avail_start = m68k_round_page(nextpa);
482 	avail_remaining = 0;
483 	avail_range = -1;
484 	for (i = 0; i < numranges; i++) {
485 		if (low[i] <= avail_next && avail_next < high[i]) {
486 			avail_range = i;
487 			avail_remaining = high[i] - avail_next;
488 		} else if (avail_range != -1) {
489 			avail_remaining += (high[i] - low[i]);
490 		}
491 	}
492 	physmem = m68k_btop(avail_remaining + nextpa - firstpa);
493 
494 	maxaddr = high[numranges - 1] - m68k_ptob(1);
495 	high[numranges - 1] -= (m68k_round_page(MSGBUFSIZE) + m68k_ptob(1));
496 	avail_end = high[numranges - 1];
497 	mem_size = m68k_ptob(physmem);
498 	virtual_end = VM_MAX_KERNEL_ADDRESS;
499 
500 	/*
501 	 * Allocate some fixed, special purpose kernel virtual addresses
502 	 */
503 	{
504 		vaddr_t va = virtual_avail;
505 
506 		CADDR1 = (void *)va;
507 		va += PAGE_SIZE;
508 		CADDR2 = (void *)va;
509 		va += PAGE_SIZE;
510 		vmmap = (void *)va;
511 		va += PAGE_SIZE;
512 		msgbufaddr = (void *)va;
513 		va += m68k_round_page(MSGBUFSIZE);
514 		virtual_avail = va;
515 	}
516 }
517 
518 void
519 bootstrap_mac68k(int tc)
520 {
521 #if NZSC > 0
522 	extern void zs_init(void);
523 #endif
524 	extern int *esym;
525 	paddr_t nextpa;
526 	void *oldROMBase;
527 
528 	if (mac68k_machine.do_graybars)
529 		printf("Bootstrapping NetBSD/mac68k.\n");
530 
531 	oldROMBase = ROMBase;
532 	mac68k_video.mv_phys = mac68k_video.mv_kvaddr;
533 
534 	if (((tc & 0x80000000) && (mmutype == MMU_68030)) ||
535 	    ((tc & 0x8000) && (mmutype == MMU_68040))) {
536 		if (mac68k_machine.do_graybars)
537 			printf("Getting mapping from MMU.\n");
538 		(void) get_mapping();
539 		if (mac68k_machine.do_graybars)
540 			printf("Done.\n");
541 	} else {
542 		/* MMU not enabled.  Fake up ranges. */
543 		numranges = 1;
544 		low[0] = 0;
545 		high[0] = mac68k_machine.mach_memsize * (1024 * 1024);
546 		if (mac68k_machine.do_graybars)
547 			printf("Faked range to byte 0x%lx.\n", high[0]);
548 	}
549 	nextpa = load_addr + m68k_round_page(esym);
550 
551 	if (mac68k_machine.do_graybars)
552 		printf("Bootstrapping the pmap system.\n");
553 
554 	pmap_bootstrap(nextpa, load_addr);
555 
556 	if (mac68k_machine.do_graybars)
557 		printf("Pmap bootstrapped.\n");
558 
559 	if (!vidlen)
560 		panic("Don't know how to relocate video!");
561 
562 	if (mac68k_machine.do_graybars)
563 		printf("Moving ROMBase from %p to %p.\n", oldROMBase, ROMBase);
564 
565 	mrg_fixupROMBase(oldROMBase, ROMBase);
566 
567 	if (mac68k_machine.do_graybars)
568 		printf("Video address 0x%p -> 0x%p.\n",
569 		    (void *)mac68k_video.mv_kvaddr, (void *)newvideoaddr);
570 
571 	mac68k_set_io_offsets(IOBase);
572 
573 	/*
574 	 * If the serial ports are going (for console or 'echo'), then
575 	 * we need to make sure the IO change gets propagated properly.
576 	 * This resets the base addresses for the 8530 (serial) driver.
577 	 *
578 	 * WARNING!!! No printfs() (etc) BETWEEN zs_init() and the end
579 	 * of this function (where we start using the MMU, so the new
580 	 * address is correct.
581 	 */
582 #if NZSC > 0
583 	if (zsinited != 0)
584 		zs_init();
585 #endif
586 
587 	mac68k_video.mv_kvaddr = newvideoaddr;
588 }
589