xref: /illumos-gate/usr/src/uts/common/os/dumpsubr.c (revision 6ccea422)
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 /*
23  * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright 2018 Joyent, Inc.
25  * Copyright 2018 Nexenta Systems, Inc. All rights reserved.
26  */
27 
28 #include <sys/types.h>
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/vm.h>
32 #include <sys/proc.h>
33 #include <sys/file.h>
34 #include <sys/conf.h>
35 #include <sys/kmem.h>
36 #include <sys/mem.h>
37 #include <sys/mman.h>
38 #include <sys/vnode.h>
39 #include <sys/errno.h>
40 #include <sys/memlist.h>
41 #include <sys/dumphdr.h>
42 #include <sys/dumpadm.h>
43 #include <sys/ksyms.h>
44 #include <sys/compress.h>
45 #include <sys/stream.h>
46 #include <sys/strsun.h>
47 #include <sys/cmn_err.h>
48 #include <sys/bitmap.h>
49 #include <sys/modctl.h>
50 #include <sys/utsname.h>
51 #include <sys/systeminfo.h>
52 #include <sys/vmem.h>
53 #include <sys/log.h>
54 #include <sys/var.h>
55 #include <sys/debug.h>
56 #include <sys/sunddi.h>
57 #include <fs/fs_subr.h>
58 #include <sys/fs/snode.h>
59 #include <sys/ontrap.h>
60 #include <sys/panic.h>
61 #include <sys/dkio.h>
62 #include <sys/vtoc.h>
63 #include <sys/errorq.h>
64 #include <sys/fm/util.h>
65 #include <sys/fs/zfs.h>
66 
67 #include <vm/hat.h>
68 #include <vm/as.h>
69 #include <vm/page.h>
70 #include <vm/pvn.h>
71 #include <vm/seg.h>
72 #include <vm/seg_kmem.h>
73 #include <sys/clock_impl.h>
74 #include <sys/hold_page.h>
75 #include <sys/cpu.h>
76 
77 #include <bzip2/bzlib.h>
78 
79 #define	ONE_GIG	(1024 * 1024 * 1024UL)
80 
81 /*
82  * Crash dump time is dominated by disk write time.  To reduce this,
83  * the stronger compression method bzip2 is applied to reduce the dump
84  * size and hence reduce I/O time.  However, bzip2 is much more
85  * computationally expensive than the existing lzjb algorithm, so to
86  * avoid increasing compression time, CPUs that are otherwise idle
87  * during panic are employed to parallelize the compression task.
88  * Many helper CPUs are needed to prevent bzip2 from being a
89  * bottleneck, and on systems with too few CPUs, the lzjb algorithm is
90  * parallelized instead. Lastly, I/O and compression are performed by
91  * different CPUs, and are hence overlapped in time, unlike the older
92  * serial code.
93  *
94  * Another important consideration is the speed of the dump
95  * device. Faster disks need less CPUs in order to benefit from
96  * parallel lzjb versus parallel bzip2. Therefore, the CPU count
97  * threshold for switching from parallel lzjb to paralled bzip2 is
98  * elevated for faster disks. The dump device speed is adduced from
99  * the setting for dumpbuf.iosize, see dump_update_clevel.
100  */
101 
102 /*
103  * exported vars
104  */
105 kmutex_t	dump_lock;		/* lock for dump configuration */
106 dumphdr_t	*dumphdr;		/* dump header */
107 int		dump_conflags = DUMP_KERNEL; /* dump configuration flags */
108 vnode_t		*dumpvp;		/* dump device vnode pointer */
109 u_offset_t	dumpvp_size;		/* size of dump device, in bytes */
110 char		*dumppath;		/* pathname of dump device */
111 int		dump_timeout = 120;	/* timeout for dumping pages */
112 int		dump_timeleft;		/* portion of dump_timeout remaining */
113 int		dump_ioerr;		/* dump i/o error */
114 int		dump_check_used;	/* enable check for used pages */
115 char	    *dump_stack_scratch; /* scratch area for saving stack summary */
116 
117 /*
118  * Tunables for dump compression and parallelism. These can be set via
119  * /etc/system.
120  *
121  * dump_ncpu_low	number of helpers for parallel lzjb
122  *	This is also the minimum configuration.
123  *
124  * dump_bzip2_level	bzip2 compression level: 1-9
125  *	Higher numbers give greater compression, but take more memory
126  *	and time. Memory used per helper is ~(dump_bzip2_level * 1MB).
127  *
128  * dump_plat_mincpu	the cross-over limit for using bzip2 (per platform):
129  *	if dump_plat_mincpu == 0, then always do single threaded dump
130  *	if ncpu >= dump_plat_mincpu then try to use bzip2
131  *
132  * dump_metrics_on	if set, metrics are collected in the kernel, passed
133  *	to savecore via the dump file, and recorded by savecore in
134  *	METRICS.txt.
135  */
136 uint_t dump_ncpu_low = 4;	/* minimum config for parallel lzjb */
137 uint_t dump_bzip2_level = 1;	/* bzip2 level (1-9) */
138 
139 /* Use dump_plat_mincpu_default unless this variable is set by /etc/system */
140 #define	MINCPU_NOT_SET	((uint_t)-1)
141 uint_t dump_plat_mincpu = MINCPU_NOT_SET;
142 
143 /* tunables for pre-reserved heap */
144 uint_t dump_kmem_permap = 1024;
145 uint_t dump_kmem_pages = 0;
146 
147 /* Define multiple buffers per helper to avoid stalling */
148 #define	NCBUF_PER_HELPER	2
149 #define	NCMAP_PER_HELPER	4
150 
151 /* minimum number of helpers configured */
152 #define	MINHELPERS	(dump_ncpu_low)
153 #define	MINCBUFS	(MINHELPERS * NCBUF_PER_HELPER)
154 
155 /*
156  * Define constant parameters.
157  *
158  * CBUF_SIZE		size of an output buffer
159  *
160  * CBUF_MAPSIZE		size of virtual range for mapping pages
161  *
162  * CBUF_MAPNP		size of virtual range in pages
163  *
164  */
165 #define	DUMP_1KB	((size_t)1 << 10)
166 #define	DUMP_1MB	((size_t)1 << 20)
167 #define	CBUF_SIZE	((size_t)1 << 17)
168 #define	CBUF_MAPSHIFT	(22)
169 #define	CBUF_MAPSIZE	((size_t)1 << CBUF_MAPSHIFT)
170 #define	CBUF_MAPNP	((size_t)1 << (CBUF_MAPSHIFT - PAGESHIFT))
171 
172 /*
173  * Compression metrics are accumulated nano-second subtotals. The
174  * results are normalized by the number of pages dumped. A report is
175  * generated when dumpsys() completes and is saved in the dump image
176  * after the trailing dump header.
177  *
178  * Metrics are always collected. Set the variable dump_metrics_on to
179  * cause metrics to be saved in the crash file, where savecore will
180  * save it in the file METRICS.txt.
181  */
182 #define	PERPAGES \
183 	PERPAGE(bitmap) PERPAGE(map) PERPAGE(unmap) \
184 	PERPAGE(copy) PERPAGE(compress) \
185 	PERPAGE(write) \
186 	PERPAGE(inwait) PERPAGE(outwait)
187 
188 typedef struct perpage {
189 #define	PERPAGE(x) hrtime_t x;
190 	PERPAGES
191 #undef PERPAGE
192 } perpage_t;
193 
194 /*
195  * This macro controls the code generation for collecting dump
196  * performance information. By default, the code is generated, but
197  * automatic saving of the information is disabled. If dump_metrics_on
198  * is set to 1, the timing information is passed to savecore via the
199  * crash file, where it is appended to the file dump-dir/METRICS.txt.
200  */
201 #define	COLLECT_METRICS
202 
203 #ifdef COLLECT_METRICS
204 uint_t dump_metrics_on = 0;	/* set to 1 to enable recording metrics */
205 
206 #define	HRSTART(v, m)		v##ts.m = gethrtime()
207 #define	HRSTOP(v, m)		v.m += gethrtime() - v##ts.m
208 #define	HRBEGIN(v, m, s)	v##ts.m = gethrtime(); v.size += s
209 #define	HREND(v, m)		v.m += gethrtime() - v##ts.m
210 #define	HRNORM(v, m, n)		v.m /= (n)
211 
212 #else
213 #define	HRSTART(v, m)
214 #define	HRSTOP(v, m)
215 #define	HRBEGIN(v, m, s)
216 #define	HREND(v, m)
217 #define	HRNORM(v, m, n)
218 #endif	/* COLLECT_METRICS */
219 
220 /*
221  * Buffers for copying and compressing memory pages.
222  *
223  * cbuf_t buffer controllers: used for both input and output.
224  *
225  * The buffer state indicates how it is being used:
226  *
227  * CBUF_FREEMAP: CBUF_MAPSIZE virtual address range is available for
228  * mapping input pages.
229  *
230  * CBUF_INREADY: input pages are mapped and ready for compression by a
231  * helper.
232  *
233  * CBUF_USEDMAP: mapping has been consumed by a helper. Needs unmap.
234  *
235  * CBUF_FREEBUF: CBUF_SIZE output buffer, which is available.
236  *
237  * CBUF_WRITE: CBUF_SIZE block of compressed pages from a helper,
238  * ready to write out.
239  *
240  * CBUF_ERRMSG: CBUF_SIZE block of error messages from a helper
241  * (reports UE errors.)
242  */
243 
244 typedef enum cbufstate {
245 	CBUF_FREEMAP,
246 	CBUF_INREADY,
247 	CBUF_USEDMAP,
248 	CBUF_FREEBUF,
249 	CBUF_WRITE,
250 	CBUF_ERRMSG
251 } cbufstate_t;
252 
253 typedef struct cbuf cbuf_t;
254 
255 struct cbuf {
256 	cbuf_t *next;			/* next in list */
257 	cbufstate_t state;		/* processing state */
258 	size_t used;			/* amount used */
259 	size_t size;			/* mem size */
260 	char *buf;			/* kmem or vmem */
261 	pgcnt_t pagenum;		/* index to pfn map */
262 	pgcnt_t bitnum;			/* first set bitnum */
263 	pfn_t pfn;			/* first pfn in mapped range */
264 	int off;			/* byte offset to first pfn */
265 };
266 
267 static char dump_osimage_uuid[36 + 1];
268 
269 #define	isdigit(ch)	((ch) >= '0' && (ch) <= '9')
270 #define	isxdigit(ch)	(isdigit(ch) || ((ch) >= 'a' && (ch) <= 'f') || \
271 			((ch) >= 'A' && (ch) <= 'F'))
272 
273 /*
274  * cqueue_t queues: a uni-directional channel for communication
275  * from the master to helper tasks or vice-versa using put and
276  * get primitives. Both mappings and data buffers are passed via
277  * queues. Producers close a queue when done. The number of
278  * active producers is reference counted so the consumer can
279  * detect end of data. Concurrent access is mediated by atomic
280  * operations for panic dump, or mutex/cv for live dump.
281  *
282  * There a four queues, used as follows:
283  *
284  * Queue		Dataflow		NewState
285  * --------------------------------------------------
286  * mainq		master -> master	FREEMAP
287  * master has initialized or unmapped an input buffer
288  * --------------------------------------------------
289  * helperq		master -> helper	INREADY
290  * master has mapped input for use by helper
291  * --------------------------------------------------
292  * mainq		master <- helper	USEDMAP
293  * helper is done with input
294  * --------------------------------------------------
295  * freebufq		master -> helper	FREEBUF
296  * master has initialized or written an output buffer
297  * --------------------------------------------------
298  * mainq		master <- helper	WRITE
299  * block of compressed pages from a helper
300  * --------------------------------------------------
301  * mainq		master <- helper	ERRMSG
302  * error messages from a helper (memory error case)
303  * --------------------------------------------------
304  * writerq		master <- master	WRITE
305  * non-blocking queue of blocks to write
306  * --------------------------------------------------
307  */
308 typedef struct cqueue {
309 	cbuf_t *volatile first;		/* first in list */
310 	cbuf_t *last;			/* last in list */
311 	hrtime_t ts;			/* timestamp */
312 	hrtime_t empty;			/* total time empty */
313 	kmutex_t mutex;			/* live state lock */
314 	kcondvar_t cv;			/* live wait var */
315 	lock_t spinlock;		/* panic mode spin lock */
316 	volatile uint_t open;		/* producer ref count */
317 } cqueue_t;
318 
319 /*
320  * Convenience macros for using the cqueue functions
321  * Note that the caller must have defined "dumpsync_t *ds"
322  */
323 #define	CQ_IS_EMPTY(q)					\
324 	(ds->q.first == NULL)
325 
326 #define	CQ_OPEN(q)					\
327 	atomic_inc_uint(&ds->q.open)
328 
329 #define	CQ_CLOSE(q)					\
330 	dumpsys_close_cq(&ds->q, ds->live)
331 
332 #define	CQ_PUT(q, cp, st)				\
333 	dumpsys_put_cq(&ds->q, cp, st, ds->live)
334 
335 #define	CQ_GET(q)					\
336 	dumpsys_get_cq(&ds->q, ds->live)
337 
338 /*
339  * Dynamic state when dumpsys() is running.
340  */
341 typedef struct dumpsync {
342 	pgcnt_t npages;			/* subtotal of pages dumped */
343 	pgcnt_t pages_mapped;		/* subtotal of pages mapped */
344 	pgcnt_t pages_used;		/* subtotal of pages used per map */
345 	size_t nwrite;			/* subtotal of bytes written */
346 	uint_t live;			/* running live dump */
347 	uint_t neednl;			/* will need to print a newline */
348 	uint_t percent;			/* dump progress */
349 	uint_t percent_done;		/* dump progress reported */
350 	int sec_done;			/* dump progress last report time */
351 	cqueue_t freebufq;		/* free kmem bufs for writing */
352 	cqueue_t mainq;			/* input for main task */
353 	cqueue_t helperq;		/* input for helpers */
354 	cqueue_t writerq;		/* input for writer */
355 	hrtime_t start;			/* start time */
356 	hrtime_t elapsed;		/* elapsed time when completed */
357 	hrtime_t iotime;		/* time spent writing nwrite bytes */
358 	hrtime_t iowait;		/* time spent waiting for output */
359 	hrtime_t iowaitts;		/* iowait timestamp */
360 	perpage_t perpage;		/* metrics */
361 	perpage_t perpagets;
362 	int dumpcpu;			/* master cpu */
363 } dumpsync_t;
364 
365 static dumpsync_t dumpsync;		/* synchronization vars */
366 
367 /*
368  * helper_t helpers: contains the context for a stream. CPUs run in
369  * parallel at dump time; each CPU creates a single stream of
370  * compression data.  Stream data is divided into CBUF_SIZE blocks.
371  * The blocks are written in order within a stream. But, blocks from
372  * multiple streams can be interleaved. Each stream is identified by a
373  * unique tag.
374  */
375 typedef struct helper {
376 	int helper;			/* bound helper id */
377 	int tag;			/* compression stream tag */
378 	perpage_t perpage;		/* per page metrics */
379 	perpage_t perpagets;		/* per page metrics (timestamps) */
380 	taskqid_t taskqid;		/* live dump task ptr */
381 	int in, out;			/* buffer offsets */
382 	cbuf_t *cpin, *cpout, *cperr;	/* cbuf objects in process */
383 	dumpsync_t *ds;			/* pointer to sync vars */
384 	size_t used;			/* counts input consumed */
385 	char *page;			/* buffer for page copy */
386 	char *lzbuf;			/* lzjb output */
387 	bz_stream bzstream;		/* bzip2 state */
388 } helper_t;
389 
390 #define	MAINHELPER	(-1)		/* helper is also the main task */
391 #define	FREEHELPER	(-2)		/* unbound helper */
392 #define	DONEHELPER	(-3)		/* helper finished */
393 
394 /*
395  * configuration vars for dumpsys
396  */
397 typedef struct dumpcfg {
398 	int	threshold;	/* ncpu threshold for bzip2 */
399 	int	nhelper;	/* number of helpers */
400 	int	nhelper_used;	/* actual number of helpers used */
401 	int	ncmap;		/* number VA pages for compression */
402 	int	ncbuf;		/* number of bufs for compression */
403 	int	ncbuf_used;	/* number of bufs in use */
404 	uint_t	clevel;		/* dump compression level */
405 	helper_t *helper;	/* array of helpers */
406 	cbuf_t	*cmap;		/* array of input (map) buffers */
407 	cbuf_t	*cbuf;		/* array of output  buffers */
408 	ulong_t	*helpermap;	/* set of dumpsys helper CPU ids */
409 	ulong_t	*bitmap;	/* bitmap for marking pages to dump */
410 	ulong_t	*rbitmap;	/* bitmap for used CBUF_MAPSIZE ranges */
411 	pgcnt_t	bitmapsize;	/* size of bitmap */
412 	pgcnt_t	rbitmapsize;	/* size of bitmap for ranges */
413 	pgcnt_t found4m;	/* number ranges allocated by dump */
414 	pgcnt_t foundsm;	/* number small pages allocated by dump */
415 	pid_t	*pids;		/* list of process IDs at dump time */
416 	size_t	maxsize;	/* memory size needed at dump time */
417 	size_t	maxvmsize;	/* size of reserved VM */
418 	char	*maxvm;		/* reserved VM for spare pages */
419 	lock_t	helper_lock;	/* protect helper state */
420 	char	helpers_wanted;	/* flag to enable parallelism */
421 } dumpcfg_t;
422 
423 static dumpcfg_t dumpcfg;	/* config vars */
424 
425 /*
426  * The dump I/O buffer.
427  *
428  * There is one I/O buffer used by dumpvp_write and dumvp_flush. It is
429  * sized according to the optimum device transfer speed.
430  */
431 typedef struct dumpbuf {
432 	vnode_t	*cdev_vp;	/* VCHR open of the dump device */
433 	len_t	vp_limit;	/* maximum write offset */
434 	offset_t vp_off;	/* current dump device offset */
435 	char	*cur;		/* dump write pointer */
436 	char	*start;		/* dump buffer address */
437 	char	*end;		/* dump buffer end */
438 	size_t	size;		/* size of dumpbuf in bytes */
439 	size_t	iosize;		/* best transfer size for device */
440 } dumpbuf_t;
441 
442 dumpbuf_t dumpbuf;		/* I/O buffer */
443 
444 /*
445  * For parallel dump, defines maximum time main task thread will wait
446  * for at least one helper to register in dumpcfg.helpermap, before
447  * assuming there are no helpers and falling back to serial mode.
448  * Value is chosen arbitrary and provides *really* long wait for any
449  * available helper to register.
450  */
451 #define	DUMP_HELPER_MAX_WAIT	1000	/* millisec */
452 
453 /*
454  * The dump I/O buffer must be at least one page, at most xfer_size
455  * bytes, and should scale with physmem in between.  The transfer size
456  * passed in will either represent a global default (maxphys) or the
457  * best size for the device.  The size of the dumpbuf I/O buffer is
458  * limited by dumpbuf_limit (8MB by default) because the dump
459  * performance saturates beyond a certain size.  The default is to
460  * select 1/4096 of the memory.
461  */
462 static int	dumpbuf_fraction = 12;	/* memory size scale factor */
463 static size_t	dumpbuf_limit = 8 * DUMP_1MB;	/* max I/O buf size */
464 
465 static size_t
466 dumpbuf_iosize(size_t xfer_size)
467 {
468 	size_t iosize = ptob(physmem >> dumpbuf_fraction);
469 
470 	if (iosize < PAGESIZE)
471 		iosize = PAGESIZE;
472 	else if (iosize > xfer_size)
473 		iosize = xfer_size;
474 	if (iosize > dumpbuf_limit)
475 		iosize = dumpbuf_limit;
476 	return (iosize & PAGEMASK);
477 }
478 
479 /*
480  * resize the I/O buffer
481  */
482 static void
483 dumpbuf_resize(void)
484 {
485 	char *old_buf = dumpbuf.start;
486 	size_t old_size = dumpbuf.size;
487 	char *new_buf;
488 	size_t new_size;
489 
490 	ASSERT(MUTEX_HELD(&dump_lock));
491 
492 	new_size = dumpbuf_iosize(MAX(dumpbuf.iosize, maxphys));
493 	if (new_size <= old_size)
494 		return; /* no need to reallocate buffer */
495 
496 	new_buf = kmem_alloc(new_size, KM_SLEEP);
497 	dumpbuf.size = new_size;
498 	dumpbuf.start = new_buf;
499 	dumpbuf.end = new_buf + new_size;
500 	kmem_free(old_buf, old_size);
501 }
502 
503 /*
504  * dump_update_clevel is called when dumpadm configures the dump device.
505  *	Calculate number of helpers and buffers.
506  *	Allocate the minimum configuration for now.
507  *
508  * When the dump file is configured we reserve a minimum amount of
509  * memory for use at crash time. But we reserve VA for all the memory
510  * we really want in order to do the fastest dump possible. The VA is
511  * backed by pages not being dumped, according to the bitmap. If
512  * there is insufficient spare memory, however, we fall back to the
513  * minimum.
514  *
515  * Live dump (savecore -L) always uses the minimum config.
516  *
517  * clevel 0 is single threaded lzjb
518  * clevel 1 is parallel lzjb
519  * clevel 2 is parallel bzip2
520  *
521  * The ncpu threshold is selected with dump_plat_mincpu.
522  * On OPL, set_platform_defaults() overrides the sun4u setting.
523  * The actual values are defined via DUMP_PLAT_*_MINCPU macros.
524  *
525  * Architecture		Threshold	Algorithm
526  * sun4u		<  51		parallel lzjb
527  * sun4u		>= 51		parallel bzip2(*)
528  * sun4u OPL		<  8		parallel lzjb
529  * sun4u OPL		>= 8		parallel bzip2(*)
530  * sun4v		<  128		parallel lzjb
531  * sun4v		>= 128		parallel bzip2(*)
532  * x86			< 11		parallel lzjb
533  * x86			>= 11		parallel bzip2(*)
534  * 32-bit		N/A		single-threaded lzjb
535  *
536  * (*) bzip2 is only chosen if there is sufficient available
537  * memory for buffers at dump time. See dumpsys_get_maxmem().
538  *
539  * Faster dump devices have larger I/O buffers. The threshold value is
540  * increased according to the size of the dump I/O buffer, because
541  * parallel lzjb performs better with faster disks. For buffers >= 1MB
542  * the threshold is 3X; for buffers >= 256K threshold is 2X.
543  *
544  * For parallel dumps, the number of helpers is ncpu-1. The CPU
545  * running panic runs the main task. For single-threaded dumps, the
546  * panic CPU does lzjb compression (it is tagged as MAINHELPER.)
547  *
548  * Need multiple buffers per helper so that they do not block waiting
549  * for the main task.
550  *				parallel	single-threaded
551  * Number of output buffers:	nhelper*2		1
552  * Number of mapping buffers:	nhelper*4		1
553  *
554  */
555 static void
556 dump_update_clevel()
557 {
558 	int tag;
559 	size_t bz2size;
560 	helper_t *hp, *hpend;
561 	cbuf_t *cp, *cpend;
562 	dumpcfg_t *old = &dumpcfg;
563 	dumpcfg_t newcfg = *old;
564 	dumpcfg_t *new = &newcfg;
565 
566 	ASSERT(MUTEX_HELD(&dump_lock));
567 
568 	/*
569 	 * Free the previously allocated bufs and VM.
570 	 */
571 	if (old->helper != NULL) {
572 
573 		/* helpers */
574 		hpend = &old->helper[old->nhelper];
575 		for (hp = old->helper; hp != hpend; hp++) {
576 			if (hp->lzbuf != NULL)
577 				kmem_free(hp->lzbuf, PAGESIZE);
578 			if (hp->page != NULL)
579 				kmem_free(hp->page, PAGESIZE);
580 		}
581 		kmem_free(old->helper, old->nhelper * sizeof (helper_t));
582 
583 		/* VM space for mapping pages */
584 		cpend = &old->cmap[old->ncmap];
585 		for (cp = old->cmap; cp != cpend; cp++)
586 			vmem_xfree(heap_arena, cp->buf, CBUF_MAPSIZE);
587 		kmem_free(old->cmap, old->ncmap * sizeof (cbuf_t));
588 
589 		/* output bufs */
590 		cpend = &old->cbuf[old->ncbuf];
591 		for (cp = old->cbuf; cp != cpend; cp++)
592 			if (cp->buf != NULL)
593 				kmem_free(cp->buf, cp->size);
594 		kmem_free(old->cbuf, old->ncbuf * sizeof (cbuf_t));
595 
596 		/* reserved VM for dumpsys_get_maxmem */
597 		if (old->maxvmsize > 0)
598 			vmem_xfree(heap_arena, old->maxvm, old->maxvmsize);
599 	}
600 
601 	/*
602 	 * Allocate memory and VM.
603 	 * One CPU runs dumpsys, the rest are helpers.
604 	 */
605 	new->nhelper = ncpus - 1;
606 	if (new->nhelper < 1)
607 		new->nhelper = 1;
608 
609 	if (new->nhelper > DUMP_MAX_NHELPER)
610 		new->nhelper = DUMP_MAX_NHELPER;
611 
612 	/* use platform default, unless /etc/system overrides */
613 	if (dump_plat_mincpu == MINCPU_NOT_SET)
614 		dump_plat_mincpu = dump_plat_mincpu_default;
615 
616 	/* increase threshold for faster disks */
617 	new->threshold = dump_plat_mincpu;
618 	if (dumpbuf.iosize >= DUMP_1MB)
619 		new->threshold *= 3;
620 	else if (dumpbuf.iosize >= (256 * DUMP_1KB))
621 		new->threshold *= 2;
622 
623 	/* figure compression level based upon the computed threshold. */
624 	if (dump_plat_mincpu == 0 || new->nhelper < 2) {
625 		new->clevel = 0;
626 		new->nhelper = 1;
627 	} else if ((new->nhelper + 1) >= new->threshold) {
628 		new->clevel = DUMP_CLEVEL_BZIP2;
629 	} else {
630 		new->clevel = DUMP_CLEVEL_LZJB;
631 	}
632 
633 	if (new->clevel == 0) {
634 		new->ncbuf = 1;
635 		new->ncmap = 1;
636 	} else {
637 		new->ncbuf = NCBUF_PER_HELPER * new->nhelper;
638 		new->ncmap = NCMAP_PER_HELPER * new->nhelper;
639 	}
640 
641 	/*
642 	 * Allocate new data structures and buffers for MINHELPERS,
643 	 * and also figure the max desired size.
644 	 */
645 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
646 	new->maxsize = 0;
647 	new->maxvmsize = 0;
648 	new->maxvm = NULL;
649 	tag = 1;
650 	new->helper = kmem_zalloc(new->nhelper * sizeof (helper_t), KM_SLEEP);
651 	hpend = &new->helper[new->nhelper];
652 	for (hp = new->helper; hp != hpend; hp++) {
653 		hp->tag = tag++;
654 		if (hp < &new->helper[MINHELPERS]) {
655 			hp->lzbuf = kmem_alloc(PAGESIZE, KM_SLEEP);
656 			hp->page = kmem_alloc(PAGESIZE, KM_SLEEP);
657 		} else if (new->clevel < DUMP_CLEVEL_BZIP2) {
658 			new->maxsize += 2 * PAGESIZE;
659 		} else {
660 			new->maxsize += PAGESIZE;
661 		}
662 		if (new->clevel >= DUMP_CLEVEL_BZIP2)
663 			new->maxsize += bz2size;
664 	}
665 
666 	new->cbuf = kmem_zalloc(new->ncbuf * sizeof (cbuf_t), KM_SLEEP);
667 	cpend = &new->cbuf[new->ncbuf];
668 	for (cp = new->cbuf; cp != cpend; cp++) {
669 		cp->state = CBUF_FREEBUF;
670 		cp->size = CBUF_SIZE;
671 		if (cp < &new->cbuf[MINCBUFS])
672 			cp->buf = kmem_alloc(cp->size, KM_SLEEP);
673 		else
674 			new->maxsize += cp->size;
675 	}
676 
677 	new->cmap = kmem_zalloc(new->ncmap * sizeof (cbuf_t), KM_SLEEP);
678 	cpend = &new->cmap[new->ncmap];
679 	for (cp = new->cmap; cp != cpend; cp++) {
680 		cp->state = CBUF_FREEMAP;
681 		cp->size = CBUF_MAPSIZE;
682 		cp->buf = vmem_xalloc(heap_arena, CBUF_MAPSIZE, CBUF_MAPSIZE,
683 		    0, 0, NULL, NULL, VM_SLEEP);
684 	}
685 
686 	/* reserve VA to be backed with spare pages at crash time */
687 	if (new->maxsize > 0) {
688 		new->maxsize = P2ROUNDUP(new->maxsize, PAGESIZE);
689 		new->maxvmsize = P2ROUNDUP(new->maxsize, CBUF_MAPSIZE);
690 		new->maxvm = vmem_xalloc(heap_arena, new->maxvmsize,
691 		    CBUF_MAPSIZE, 0, 0, NULL, NULL, VM_SLEEP);
692 	}
693 
694 	/*
695 	 * Reserve memory for kmem allocation calls made during crash dump.  The
696 	 * hat layer allocates memory for each mapping created, and the I/O path
697 	 * allocates buffers and data structs.
698 	 *
699 	 * On larger systems, we easily exceed the lower amount, so we need some
700 	 * more space; the cut-over point is relatively arbitrary.  If we run
701 	 * out, the only impact is that kmem state in the dump becomes
702 	 * inconsistent.
703 	 */
704 
705 	if (dump_kmem_pages == 0) {
706 		if (physmem > (16 * ONE_GIG) / PAGESIZE)
707 			dump_kmem_pages = 20;
708 		else
709 			dump_kmem_pages = 8;
710 	}
711 
712 	kmem_dump_init((new->ncmap * dump_kmem_permap) +
713 	    (dump_kmem_pages * PAGESIZE));
714 
715 	/* set new config pointers */
716 	*old = *new;
717 }
718 
719 /*
720  * Define a struct memlist walker to optimize bitnum to pfn
721  * lookup. The walker maintains the state of the list traversal.
722  */
723 typedef struct dumpmlw {
724 	struct memlist	*mp;		/* current memlist */
725 	pgcnt_t		basenum;	/* bitnum base offset */
726 	pgcnt_t		mppages;	/* current memlist size */
727 	pgcnt_t		mpleft;		/* size to end of current memlist */
728 	pfn_t		mpaddr;		/* first pfn in memlist */
729 } dumpmlw_t;
730 
731 /* initialize the walker */
732 static inline void
733 dump_init_memlist_walker(dumpmlw_t *pw)
734 {
735 	pw->mp = phys_install;
736 	pw->basenum = 0;
737 	pw->mppages = pw->mp->ml_size >> PAGESHIFT;
738 	pw->mpleft = pw->mppages;
739 	pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
740 }
741 
742 /*
743  * Lookup pfn given bitnum. The memlist can be quite long on some
744  * systems (e.g.: one per board). To optimize sequential lookups, the
745  * caller initializes and presents a memlist walker.
746  */
747 static pfn_t
748 dump_bitnum_to_pfn(pgcnt_t bitnum, dumpmlw_t *pw)
749 {
750 	bitnum -= pw->basenum;
751 	while (pw->mp != NULL) {
752 		if (bitnum < pw->mppages) {
753 			pw->mpleft = pw->mppages - bitnum;
754 			return (pw->mpaddr + bitnum);
755 		}
756 		bitnum -= pw->mppages;
757 		pw->basenum += pw->mppages;
758 		pw->mp = pw->mp->ml_next;
759 		if (pw->mp != NULL) {
760 			pw->mppages = pw->mp->ml_size >> PAGESHIFT;
761 			pw->mpleft = pw->mppages;
762 			pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
763 		}
764 	}
765 	return (PFN_INVALID);
766 }
767 
768 static pgcnt_t
769 dump_pfn_to_bitnum(pfn_t pfn)
770 {
771 	struct memlist *mp;
772 	pgcnt_t bitnum = 0;
773 
774 	for (mp = phys_install; mp != NULL; mp = mp->ml_next) {
775 		if (pfn >= (mp->ml_address >> PAGESHIFT) &&
776 		    pfn < ((mp->ml_address + mp->ml_size) >> PAGESHIFT))
777 			return (bitnum + pfn - (mp->ml_address >> PAGESHIFT));
778 		bitnum += mp->ml_size >> PAGESHIFT;
779 	}
780 	return ((pgcnt_t)-1);
781 }
782 
783 /*
784  * Set/test bitmap for a CBUF_MAPSIZE range which includes pfn. The
785  * mapping of pfn to range index is imperfect because pfn and bitnum
786  * do not have the same phase. To make sure a CBUF_MAPSIZE range is
787  * covered, call this for both ends:
788  *	dump_set_used(base)
789  *	dump_set_used(base+CBUF_MAPNP-1)
790  *
791  * This is used during a panic dump to mark pages allocated by
792  * dumpsys_get_maxmem(). The macro IS_DUMP_PAGE(pp) is used by
793  * page_get_mnode_freelist() to make sure pages used by dump are never
794  * allocated.
795  */
796 #define	CBUF_MAPP2R(pfn)	((pfn) >> (CBUF_MAPSHIFT - PAGESHIFT))
797 
798 static void
799 dump_set_used(pfn_t pfn)
800 {
801 
802 	pgcnt_t bitnum, rbitnum;
803 
804 	bitnum = dump_pfn_to_bitnum(pfn);
805 	ASSERT(bitnum != (pgcnt_t)-1);
806 
807 	rbitnum = CBUF_MAPP2R(bitnum);
808 	ASSERT(rbitnum < dumpcfg.rbitmapsize);
809 
810 	BT_SET(dumpcfg.rbitmap, rbitnum);
811 }
812 
813 int
814 dump_test_used(pfn_t pfn)
815 {
816 	pgcnt_t bitnum, rbitnum;
817 
818 	bitnum = dump_pfn_to_bitnum(pfn);
819 	ASSERT(bitnum != (pgcnt_t)-1);
820 
821 	rbitnum = CBUF_MAPP2R(bitnum);
822 	ASSERT(rbitnum < dumpcfg.rbitmapsize);
823 
824 	return (BT_TEST(dumpcfg.rbitmap, rbitnum));
825 }
826 
827 /*
828  * dumpbzalloc and dumpbzfree are callbacks from the bzip2 library.
829  * dumpsys_get_maxmem() uses them for BZ2_bzCompressInit().
830  */
831 static void *
832 dumpbzalloc(void *opaque, int items, int size)
833 {
834 	size_t *sz;
835 	char *ret;
836 
837 	ASSERT(opaque != NULL);
838 	sz = opaque;
839 	ret = dumpcfg.maxvm + *sz;
840 	*sz += items * size;
841 	*sz = P2ROUNDUP(*sz, BZ2_BZALLOC_ALIGN);
842 	ASSERT(*sz <= dumpcfg.maxvmsize);
843 	return (ret);
844 }
845 
846 /*ARGSUSED*/
847 static void
848 dumpbzfree(void *opaque, void *addr)
849 {
850 }
851 
852 /*
853  * Perform additional checks on the page to see if we can really use
854  * it. The kernel (kas) pages are always set in the bitmap. However,
855  * boot memory pages (prom_ppages or P_BOOTPAGES) are not in the
856  * bitmap. So we check for them.
857  */
858 static inline int
859 dump_pfn_check(pfn_t pfn)
860 {
861 	page_t *pp = page_numtopp_nolock(pfn);
862 	if (pp == NULL || pp->p_pagenum != pfn ||
863 #if defined(__sparc)
864 	    pp->p_vnode == &promvp ||
865 #else
866 	    PP_ISBOOTPAGES(pp) ||
867 #endif
868 	    pp->p_toxic != 0)
869 		return (0);
870 	return (1);
871 }
872 
873 /*
874  * Check a range to see if all contained pages are available and
875  * return non-zero if the range can be used.
876  */
877 static inline int
878 dump_range_check(pgcnt_t start, pgcnt_t end, pfn_t pfn)
879 {
880 	for (; start < end; start++, pfn++) {
881 		if (BT_TEST(dumpcfg.bitmap, start))
882 			return (0);
883 		if (!dump_pfn_check(pfn))
884 			return (0);
885 	}
886 	return (1);
887 }
888 
889 /*
890  * dumpsys_get_maxmem() is called during panic. Find unused ranges
891  * and use them for buffers. If we find enough memory switch to
892  * parallel bzip2, otherwise use parallel lzjb.
893  *
894  * It searches the dump bitmap in 2 passes. The first time it looks
895  * for CBUF_MAPSIZE ranges. On the second pass it uses small pages.
896  */
897 static void
898 dumpsys_get_maxmem()
899 {
900 	dumpcfg_t *cfg = &dumpcfg;
901 	cbuf_t *endcp = &cfg->cbuf[cfg->ncbuf];
902 	helper_t *endhp = &cfg->helper[cfg->nhelper];
903 	pgcnt_t bitnum, end;
904 	size_t sz, endsz, bz2size;
905 	pfn_t pfn, off;
906 	cbuf_t *cp;
907 	helper_t *hp, *ohp;
908 	dumpmlw_t mlw;
909 	int k;
910 
911 	/*
912 	 * Setting dump_plat_mincpu to 0 at any time forces a serial
913 	 * dump.
914 	 */
915 	if (dump_plat_mincpu == 0) {
916 		cfg->clevel = 0;
917 		return;
918 	}
919 
920 	/*
921 	 * There may be no point in looking for spare memory. If
922 	 * dumping all memory, then none is spare. If doing a serial
923 	 * dump, then already have buffers.
924 	 */
925 	if (cfg->maxsize == 0 || cfg->clevel < DUMP_CLEVEL_LZJB ||
926 	    (dump_conflags & DUMP_ALL) != 0) {
927 		if (cfg->clevel > DUMP_CLEVEL_LZJB)
928 			cfg->clevel = DUMP_CLEVEL_LZJB;
929 		return;
930 	}
931 
932 	sz = 0;
933 	cfg->found4m = 0;
934 	cfg->foundsm = 0;
935 
936 	/* bitmap of ranges used to estimate which pfns are being used */
937 	bzero(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.rbitmapsize));
938 
939 	/* find ranges that are not being dumped to use for buffers */
940 	dump_init_memlist_walker(&mlw);
941 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
942 		dump_timeleft = dump_timeout;
943 		end = bitnum + CBUF_MAPNP;
944 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
945 		ASSERT(pfn != PFN_INVALID);
946 
947 		/* skip partial range at end of mem segment */
948 		if (mlw.mpleft < CBUF_MAPNP) {
949 			end = bitnum + mlw.mpleft;
950 			continue;
951 		}
952 
953 		/* skip non aligned pages */
954 		off = P2PHASE(pfn, CBUF_MAPNP);
955 		if (off != 0) {
956 			end -= off;
957 			continue;
958 		}
959 
960 		if (!dump_range_check(bitnum, end, pfn))
961 			continue;
962 
963 		ASSERT((sz + CBUF_MAPSIZE) <= cfg->maxvmsize);
964 		hat_devload(kas.a_hat, cfg->maxvm + sz, CBUF_MAPSIZE, pfn,
965 		    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
966 		sz += CBUF_MAPSIZE;
967 		cfg->found4m++;
968 
969 		/* set the bitmap for both ends to be sure to cover the range */
970 		dump_set_used(pfn);
971 		dump_set_used(pfn + CBUF_MAPNP - 1);
972 
973 		if (sz >= cfg->maxsize)
974 			goto foundmax;
975 	}
976 
977 	/* Add small pages if we can't find enough large pages. */
978 	dump_init_memlist_walker(&mlw);
979 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
980 		dump_timeleft = dump_timeout;
981 		end = bitnum + CBUF_MAPNP;
982 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
983 		ASSERT(pfn != PFN_INVALID);
984 
985 		/* Find any non-aligned pages at start and end of segment. */
986 		off = P2PHASE(pfn, CBUF_MAPNP);
987 		if (mlw.mpleft < CBUF_MAPNP) {
988 			end = bitnum + mlw.mpleft;
989 		} else if (off != 0) {
990 			end -= off;
991 		} else if (cfg->found4m && dump_test_used(pfn)) {
992 			continue;
993 		}
994 
995 		for (; bitnum < end; bitnum++, pfn++) {
996 			dump_timeleft = dump_timeout;
997 			if (BT_TEST(dumpcfg.bitmap, bitnum))
998 				continue;
999 			if (!dump_pfn_check(pfn))
1000 				continue;
1001 			ASSERT((sz + PAGESIZE) <= cfg->maxvmsize);
1002 			hat_devload(kas.a_hat, cfg->maxvm + sz, PAGESIZE, pfn,
1003 			    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
1004 			sz += PAGESIZE;
1005 			cfg->foundsm++;
1006 			dump_set_used(pfn);
1007 			if (sz >= cfg->maxsize)
1008 				goto foundmax;
1009 		}
1010 	}
1011 
1012 	/* Fall back to lzjb if we did not get enough memory for bzip2. */
1013 	endsz = (cfg->maxsize * cfg->threshold) / cfg->nhelper;
1014 	if (sz < endsz) {
1015 		cfg->clevel = DUMP_CLEVEL_LZJB;
1016 	}
1017 
1018 	/* Allocate memory for as many helpers as we can. */
1019 foundmax:
1020 
1021 	/* Byte offsets into memory found and mapped above */
1022 	endsz = sz;
1023 	sz = 0;
1024 
1025 	/* Set the size for bzip2 state. Only bzip2 needs it. */
1026 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
1027 
1028 	/* Skip the preallocate output buffers. */
1029 	cp = &cfg->cbuf[MINCBUFS];
1030 
1031 	/* Use this to move memory up from the preallocated helpers. */
1032 	ohp = cfg->helper;
1033 
1034 	/* Loop over all helpers and allocate memory. */
1035 	for (hp = cfg->helper; hp < endhp; hp++) {
1036 
1037 		/* Skip preallocated helpers by checking hp->page. */
1038 		if (hp->page == NULL) {
1039 			if (cfg->clevel <= DUMP_CLEVEL_LZJB) {
1040 				/* lzjb needs 2 1-page buffers */
1041 				if ((sz + (2 * PAGESIZE)) > endsz)
1042 					break;
1043 				hp->page = cfg->maxvm + sz;
1044 				sz += PAGESIZE;
1045 				hp->lzbuf = cfg->maxvm + sz;
1046 				sz += PAGESIZE;
1047 
1048 			} else if (ohp->lzbuf != NULL) {
1049 				/* re-use the preallocted lzjb page for bzip2 */
1050 				hp->page = ohp->lzbuf;
1051 				ohp->lzbuf = NULL;
1052 				++ohp;
1053 
1054 			} else {
1055 				/* bzip2 needs a 1-page buffer */
1056 				if ((sz + PAGESIZE) > endsz)
1057 					break;
1058 				hp->page = cfg->maxvm + sz;
1059 				sz += PAGESIZE;
1060 			}
1061 		}
1062 
1063 		/*
1064 		 * Add output buffers per helper. The number of
1065 		 * buffers per helper is determined by the ratio of
1066 		 * ncbuf to nhelper.
1067 		 */
1068 		for (k = 0; cp < endcp && (sz + CBUF_SIZE) <= endsz &&
1069 		    k < NCBUF_PER_HELPER; k++) {
1070 			cp->state = CBUF_FREEBUF;
1071 			cp->size = CBUF_SIZE;
1072 			cp->buf = cfg->maxvm + sz;
1073 			sz += CBUF_SIZE;
1074 			++cp;
1075 		}
1076 
1077 		/*
1078 		 * bzip2 needs compression state. Use the dumpbzalloc
1079 		 * and dumpbzfree callbacks to allocate the memory.
1080 		 * bzip2 does allocation only at init time.
1081 		 */
1082 		if (cfg->clevel >= DUMP_CLEVEL_BZIP2) {
1083 			if ((sz + bz2size) > endsz) {
1084 				hp->page = NULL;
1085 				break;
1086 			} else {
1087 				hp->bzstream.opaque = &sz;
1088 				hp->bzstream.bzalloc = dumpbzalloc;
1089 				hp->bzstream.bzfree = dumpbzfree;
1090 				(void) BZ2_bzCompressInit(&hp->bzstream,
1091 				    dump_bzip2_level, 0, 0);
1092 				hp->bzstream.opaque = NULL;
1093 			}
1094 		}
1095 	}
1096 
1097 	/* Finish allocating output buffers */
1098 	for (; cp < endcp && (sz + CBUF_SIZE) <= endsz; cp++) {
1099 		cp->state = CBUF_FREEBUF;
1100 		cp->size = CBUF_SIZE;
1101 		cp->buf = cfg->maxvm + sz;
1102 		sz += CBUF_SIZE;
1103 	}
1104 
1105 	/* Enable IS_DUMP_PAGE macro, which checks for pages we took. */
1106 	if (cfg->found4m || cfg->foundsm)
1107 		dump_check_used = 1;
1108 
1109 	ASSERT(sz <= endsz);
1110 }
1111 
1112 static void
1113 dumphdr_init(void)
1114 {
1115 	pgcnt_t npages = 0;
1116 
1117 	ASSERT(MUTEX_HELD(&dump_lock));
1118 
1119 	if (dumphdr == NULL) {
1120 		dumphdr = kmem_zalloc(sizeof (dumphdr_t), KM_SLEEP);
1121 		dumphdr->dump_magic = DUMP_MAGIC;
1122 		dumphdr->dump_version = DUMP_VERSION;
1123 		dumphdr->dump_wordsize = DUMP_WORDSIZE;
1124 		dumphdr->dump_pageshift = PAGESHIFT;
1125 		dumphdr->dump_pagesize = PAGESIZE;
1126 		dumphdr->dump_utsname = utsname;
1127 		(void) strcpy(dumphdr->dump_platform, platform);
1128 		dumpbuf.size = dumpbuf_iosize(maxphys);
1129 		dumpbuf.start = kmem_alloc(dumpbuf.size, KM_SLEEP);
1130 		dumpbuf.end = dumpbuf.start + dumpbuf.size;
1131 		dumpcfg.pids = kmem_alloc(v.v_proc * sizeof (pid_t), KM_SLEEP);
1132 		dumpcfg.helpermap = kmem_zalloc(BT_SIZEOFMAP(NCPU), KM_SLEEP);
1133 		LOCK_INIT_HELD(&dumpcfg.helper_lock);
1134 		dump_stack_scratch = kmem_alloc(STACK_BUF_SIZE, KM_SLEEP);
1135 		(void) strncpy(dumphdr->dump_uuid, dump_get_uuid(),
1136 		    sizeof (dumphdr->dump_uuid));
1137 	}
1138 
1139 	npages = num_phys_pages();
1140 
1141 	if (dumpcfg.bitmapsize != npages) {
1142 		size_t rlen = CBUF_MAPP2R(P2ROUNDUP(npages, CBUF_MAPNP));
1143 		void *map = kmem_alloc(BT_SIZEOFMAP(npages), KM_SLEEP);
1144 		void *rmap = kmem_alloc(BT_SIZEOFMAP(rlen), KM_SLEEP);
1145 
1146 		if (dumpcfg.bitmap != NULL)
1147 			kmem_free(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.
1148 			    bitmapsize));
1149 		if (dumpcfg.rbitmap != NULL)
1150 			kmem_free(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.
1151 			    rbitmapsize));
1152 		dumpcfg.bitmap = map;
1153 		dumpcfg.bitmapsize = npages;
1154 		dumpcfg.rbitmap = rmap;
1155 		dumpcfg.rbitmapsize = rlen;
1156 	}
1157 }
1158 
1159 /*
1160  * Establish a new dump device.
1161  */
1162 int
1163 dumpinit(vnode_t *vp, char *name, int justchecking)
1164 {
1165 	vnode_t *cvp;
1166 	vattr_t vattr;
1167 	vnode_t *cdev_vp;
1168 	int error = 0;
1169 
1170 	ASSERT(MUTEX_HELD(&dump_lock));
1171 
1172 	dumphdr_init();
1173 
1174 	cvp = common_specvp(vp);
1175 	if (cvp == dumpvp)
1176 		return (0);
1177 
1178 	/*
1179 	 * Determine whether this is a plausible dump device.  We want either:
1180 	 * (1) a real device that's not mounted and has a cb_dump routine, or
1181 	 * (2) a swapfile on some filesystem that has a vop_dump routine.
1182 	 */
1183 	if ((error = VOP_OPEN(&cvp, FREAD | FWRITE, kcred, NULL)) != 0)
1184 		return (error);
1185 
1186 	vattr.va_mask = AT_SIZE | AT_TYPE | AT_RDEV;
1187 	if ((error = VOP_GETATTR(cvp, &vattr, 0, kcred, NULL)) == 0) {
1188 		if (vattr.va_type == VBLK || vattr.va_type == VCHR) {
1189 			if (devopsp[getmajor(vattr.va_rdev)]->
1190 			    devo_cb_ops->cb_dump == nodev)
1191 				error = ENOTSUP;
1192 			else if (vfs_devismounted(vattr.va_rdev))
1193 				error = EBUSY;
1194 			if (strcmp(ddi_driver_name(VTOS(cvp)->s_dip),
1195 			    ZFS_DRIVER) == 0 &&
1196 			    IS_SWAPVP(common_specvp(cvp)))
1197 					error = EBUSY;
1198 		} else {
1199 			if (vn_matchopval(cvp, VOPNAME_DUMP, fs_nosys) ||
1200 			    !IS_SWAPVP(cvp))
1201 				error = ENOTSUP;
1202 		}
1203 	}
1204 
1205 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE)
1206 		error = ENOSPC;
1207 
1208 	if (error || justchecking) {
1209 		(void) VOP_CLOSE(cvp, FREAD | FWRITE, 1, (offset_t)0,
1210 		    kcred, NULL);
1211 		return (error);
1212 	}
1213 
1214 	VN_HOLD(cvp);
1215 
1216 	if (dumpvp != NULL)
1217 		dumpfini();	/* unconfigure the old dump device */
1218 
1219 	dumpvp = cvp;
1220 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
1221 	dumppath = kmem_alloc(strlen(name) + 1, KM_SLEEP);
1222 	(void) strcpy(dumppath, name);
1223 	dumpbuf.iosize = 0;
1224 
1225 	/*
1226 	 * If the dump device is a block device, attempt to open up the
1227 	 * corresponding character device and determine its maximum transfer
1228 	 * size.  We use this information to potentially resize dumpbuf to a
1229 	 * larger and more optimal size for performing i/o to the dump device.
1230 	 */
1231 	if (cvp->v_type == VBLK &&
1232 	    (cdev_vp = makespecvp(VTOS(cvp)->s_dev, VCHR)) != NULL) {
1233 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1234 			size_t blk_size;
1235 			struct dk_cinfo dki;
1236 			struct dk_minfo minf;
1237 
1238 			if (VOP_IOCTL(cdev_vp, DKIOCGMEDIAINFO,
1239 			    (intptr_t)&minf, FKIOCTL, kcred, NULL, NULL)
1240 			    == 0 && minf.dki_lbsize != 0)
1241 				blk_size = minf.dki_lbsize;
1242 			else
1243 				blk_size = DEV_BSIZE;
1244 
1245 			if (VOP_IOCTL(cdev_vp, DKIOCINFO, (intptr_t)&dki,
1246 			    FKIOCTL, kcred, NULL, NULL) == 0) {
1247 				dumpbuf.iosize = dki.dki_maxtransfer * blk_size;
1248 				dumpbuf_resize();
1249 			}
1250 			/*
1251 			 * If we are working with a zvol then dumpify it
1252 			 * if it's not being used as swap.
1253 			 */
1254 			if (strcmp(dki.dki_dname, ZVOL_DRIVER) == 0) {
1255 				if (IS_SWAPVP(common_specvp(cvp)))
1256 					error = EBUSY;
1257 				else if ((error = VOP_IOCTL(cdev_vp,
1258 				    DKIOCDUMPINIT, NULL, FKIOCTL, kcred,
1259 				    NULL, NULL)) != 0)
1260 					dumpfini();
1261 			}
1262 
1263 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1264 			    kcred, NULL);
1265 		}
1266 
1267 		VN_RELE(cdev_vp);
1268 	}
1269 
1270 	cmn_err(CE_CONT, "?dump on %s size %llu MB\n", name, dumpvp_size >> 20);
1271 
1272 	dump_update_clevel();
1273 
1274 	return (error);
1275 }
1276 
1277 void
1278 dumpfini(void)
1279 {
1280 	vattr_t vattr;
1281 	boolean_t is_zfs = B_FALSE;
1282 	vnode_t *cdev_vp;
1283 	ASSERT(MUTEX_HELD(&dump_lock));
1284 
1285 	kmem_free(dumppath, strlen(dumppath) + 1);
1286 
1287 	/*
1288 	 * Determine if we are using zvols for our dump device
1289 	 */
1290 	vattr.va_mask = AT_RDEV;
1291 	if (VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL) == 0) {
1292 		is_zfs = (getmajor(vattr.va_rdev) ==
1293 		    ddi_name_to_major(ZFS_DRIVER)) ? B_TRUE : B_FALSE;
1294 	}
1295 
1296 	/*
1297 	 * If we have a zvol dump device then we call into zfs so
1298 	 * that it may have a chance to cleanup.
1299 	 */
1300 	if (is_zfs &&
1301 	    (cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR)) != NULL) {
1302 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1303 			(void) VOP_IOCTL(cdev_vp, DKIOCDUMPFINI, NULL, FKIOCTL,
1304 			    kcred, NULL, NULL);
1305 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1306 			    kcred, NULL);
1307 		}
1308 		VN_RELE(cdev_vp);
1309 	}
1310 
1311 	(void) VOP_CLOSE(dumpvp, FREAD | FWRITE, 1, (offset_t)0, kcred, NULL);
1312 
1313 	VN_RELE(dumpvp);
1314 
1315 	dumpvp = NULL;
1316 	dumpvp_size = 0;
1317 	dumppath = NULL;
1318 }
1319 
1320 static offset_t
1321 dumpvp_flush(void)
1322 {
1323 	size_t size = P2ROUNDUP(dumpbuf.cur - dumpbuf.start, PAGESIZE);
1324 	hrtime_t iotime;
1325 	int err;
1326 
1327 	if (dumpbuf.vp_off + size > dumpbuf.vp_limit) {
1328 		dump_ioerr = ENOSPC;
1329 		dumpbuf.vp_off = dumpbuf.vp_limit;
1330 	} else if (size != 0) {
1331 		iotime = gethrtime();
1332 		dumpsync.iowait += iotime - dumpsync.iowaitts;
1333 		if (panicstr)
1334 			err = VOP_DUMP(dumpvp, dumpbuf.start,
1335 			    lbtodb(dumpbuf.vp_off), btod(size), NULL);
1336 		else
1337 			err = vn_rdwr(UIO_WRITE, dumpbuf.cdev_vp != NULL ?
1338 			    dumpbuf.cdev_vp : dumpvp, dumpbuf.start, size,
1339 			    dumpbuf.vp_off, UIO_SYSSPACE, 0, dumpbuf.vp_limit,
1340 			    kcred, 0);
1341 		if (err && dump_ioerr == 0)
1342 			dump_ioerr = err;
1343 		dumpsync.iowaitts = gethrtime();
1344 		dumpsync.iotime += dumpsync.iowaitts - iotime;
1345 		dumpsync.nwrite += size;
1346 		dumpbuf.vp_off += size;
1347 	}
1348 	dumpbuf.cur = dumpbuf.start;
1349 	dump_timeleft = dump_timeout;
1350 	return (dumpbuf.vp_off);
1351 }
1352 
1353 /* maximize write speed by keeping seek offset aligned with size */
1354 void
1355 dumpvp_write(const void *va, size_t size)
1356 {
1357 	size_t len, off, sz;
1358 
1359 	while (size != 0) {
1360 		len = MIN(size, dumpbuf.end - dumpbuf.cur);
1361 		if (len == 0) {
1362 			off = P2PHASE(dumpbuf.vp_off, dumpbuf.size);
1363 			if (off == 0 || !ISP2(dumpbuf.size)) {
1364 				(void) dumpvp_flush();
1365 			} else {
1366 				sz = dumpbuf.size - off;
1367 				dumpbuf.cur = dumpbuf.start + sz;
1368 				(void) dumpvp_flush();
1369 				ovbcopy(dumpbuf.start + sz, dumpbuf.start, off);
1370 				dumpbuf.cur += off;
1371 			}
1372 		} else {
1373 			bcopy(va, dumpbuf.cur, len);
1374 			va = (char *)va + len;
1375 			dumpbuf.cur += len;
1376 			size -= len;
1377 		}
1378 	}
1379 }
1380 
1381 /*ARGSUSED*/
1382 static void
1383 dumpvp_ksyms_write(const void *src, void *dst, size_t size)
1384 {
1385 	dumpvp_write(src, size);
1386 }
1387 
1388 /*
1389  * Mark 'pfn' in the bitmap and dump its translation table entry.
1390  */
1391 void
1392 dump_addpage(struct as *as, void *va, pfn_t pfn)
1393 {
1394 	mem_vtop_t mem_vtop;
1395 	pgcnt_t bitnum;
1396 
1397 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1398 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1399 			dumphdr->dump_npages++;
1400 			BT_SET(dumpcfg.bitmap, bitnum);
1401 		}
1402 		dumphdr->dump_nvtop++;
1403 		mem_vtop.m_as = as;
1404 		mem_vtop.m_va = va;
1405 		mem_vtop.m_pfn = pfn;
1406 		dumpvp_write(&mem_vtop, sizeof (mem_vtop_t));
1407 	}
1408 	dump_timeleft = dump_timeout;
1409 }
1410 
1411 /*
1412  * Mark 'pfn' in the bitmap
1413  */
1414 void
1415 dump_page(pfn_t pfn)
1416 {
1417 	pgcnt_t bitnum;
1418 
1419 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1420 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1421 			dumphdr->dump_npages++;
1422 			BT_SET(dumpcfg.bitmap, bitnum);
1423 		}
1424 	}
1425 	dump_timeleft = dump_timeout;
1426 }
1427 
1428 /*
1429  * Dump the <as, va, pfn> information for a given address space.
1430  * SEGOP_DUMP() will call dump_addpage() for each page in the segment.
1431  */
1432 static void
1433 dump_as(struct as *as)
1434 {
1435 	struct seg *seg;
1436 
1437 	AS_LOCK_ENTER(as, RW_READER);
1438 	for (seg = AS_SEGFIRST(as); seg; seg = AS_SEGNEXT(as, seg)) {
1439 		if (seg->s_as != as)
1440 			break;
1441 		if (seg->s_ops == NULL)
1442 			continue;
1443 		SEGOP_DUMP(seg);
1444 	}
1445 	AS_LOCK_EXIT(as);
1446 
1447 	if (seg != NULL)
1448 		cmn_err(CE_WARN, "invalid segment %p in address space %p",
1449 		    (void *)seg, (void *)as);
1450 }
1451 
1452 static int
1453 dump_process(pid_t pid)
1454 {
1455 	proc_t *p = sprlock(pid);
1456 
1457 	if (p == NULL)
1458 		return (-1);
1459 	if (p->p_as != &kas) {
1460 		mutex_exit(&p->p_lock);
1461 		dump_as(p->p_as);
1462 		mutex_enter(&p->p_lock);
1463 	}
1464 
1465 	sprunlock(p);
1466 
1467 	return (0);
1468 }
1469 
1470 /*
1471  * The following functions (dump_summary(), dump_ereports(), and
1472  * dump_messages()), write data to an uncompressed area within the
1473  * crashdump. The layout of these is
1474  *
1475  * +------------------------------------------------------------+
1476  * |     compressed pages       | summary | ereports | messages |
1477  * +------------------------------------------------------------+
1478  *
1479  * With the advent of saving a compressed crash dump by default, we
1480  * need to save a little more data to describe the failure mode in
1481  * an uncompressed buffer available before savecore uncompresses
1482  * the dump. Initially this is a copy of the stack trace. Additional
1483  * summary information should be added here.
1484  */
1485 
1486 void
1487 dump_summary(void)
1488 {
1489 	u_offset_t dumpvp_start;
1490 	summary_dump_t sd;
1491 
1492 	if (dumpvp == NULL || dumphdr == NULL)
1493 		return;
1494 
1495 	dumpbuf.cur = dumpbuf.start;
1496 
1497 	dumpbuf.vp_limit = dumpvp_size - (DUMP_OFFSET + DUMP_LOGSIZE +
1498 	    DUMP_ERPTSIZE);
1499 	dumpvp_start = dumpbuf.vp_limit - DUMP_SUMMARYSIZE;
1500 	dumpbuf.vp_off = dumpvp_start;
1501 
1502 	sd.sd_magic = SUMMARY_MAGIC;
1503 	sd.sd_ssum = checksum32(dump_stack_scratch, STACK_BUF_SIZE);
1504 	dumpvp_write(&sd, sizeof (sd));
1505 	dumpvp_write(dump_stack_scratch, STACK_BUF_SIZE);
1506 
1507 	sd.sd_magic = 0; /* indicate end of summary */
1508 	dumpvp_write(&sd, sizeof (sd));
1509 	(void) dumpvp_flush();
1510 }
1511 
1512 void
1513 dump_ereports(void)
1514 {
1515 	u_offset_t dumpvp_start;
1516 	erpt_dump_t ed;
1517 
1518 	if (dumpvp == NULL || dumphdr == NULL)
1519 		return;
1520 
1521 	dumpbuf.cur = dumpbuf.start;
1522 	dumpbuf.vp_limit = dumpvp_size - (DUMP_OFFSET + DUMP_LOGSIZE);
1523 	dumpvp_start = dumpbuf.vp_limit - DUMP_ERPTSIZE;
1524 	dumpbuf.vp_off = dumpvp_start;
1525 
1526 	fm_ereport_dump();
1527 	if (panicstr)
1528 		errorq_dump();
1529 
1530 	bzero(&ed, sizeof (ed)); /* indicate end of ereports */
1531 	dumpvp_write(&ed, sizeof (ed));
1532 	(void) dumpvp_flush();
1533 
1534 	if (!panicstr) {
1535 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1536 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1537 		    B_INVAL | B_FORCE, kcred, NULL);
1538 	}
1539 }
1540 
1541 void
1542 dump_messages(void)
1543 {
1544 	log_dump_t ld;
1545 	mblk_t *mctl, *mdata;
1546 	queue_t *q, *qlast;
1547 	u_offset_t dumpvp_start;
1548 
1549 	if (dumpvp == NULL || dumphdr == NULL || log_consq == NULL)
1550 		return;
1551 
1552 	dumpbuf.cur = dumpbuf.start;
1553 	dumpbuf.vp_limit = dumpvp_size - DUMP_OFFSET;
1554 	dumpvp_start = dumpbuf.vp_limit - DUMP_LOGSIZE;
1555 	dumpbuf.vp_off = dumpvp_start;
1556 
1557 	qlast = NULL;
1558 	do {
1559 		for (q = log_consq; q->q_next != qlast; q = q->q_next)
1560 			continue;
1561 		for (mctl = q->q_first; mctl != NULL; mctl = mctl->b_next) {
1562 			dump_timeleft = dump_timeout;
1563 			mdata = mctl->b_cont;
1564 			ld.ld_magic = LOG_MAGIC;
1565 			ld.ld_msgsize = MBLKL(mctl->b_cont);
1566 			ld.ld_csum = checksum32(mctl->b_rptr, MBLKL(mctl));
1567 			ld.ld_msum = checksum32(mdata->b_rptr, MBLKL(mdata));
1568 			dumpvp_write(&ld, sizeof (ld));
1569 			dumpvp_write(mctl->b_rptr, MBLKL(mctl));
1570 			dumpvp_write(mdata->b_rptr, MBLKL(mdata));
1571 		}
1572 	} while ((qlast = q) != log_consq);
1573 
1574 	ld.ld_magic = 0;		/* indicate end of messages */
1575 	dumpvp_write(&ld, sizeof (ld));
1576 	(void) dumpvp_flush();
1577 	if (!panicstr) {
1578 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1579 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1580 		    B_INVAL | B_FORCE, kcred, NULL);
1581 	}
1582 }
1583 
1584 /*
1585  * The following functions are called on multiple CPUs during dump.
1586  * They must not use most kernel services, because all cross-calls are
1587  * disabled during panic. Therefore, blocking locks and cache flushes
1588  * will not work.
1589  */
1590 
1591 /*
1592  * Copy pages, trapping ECC errors. Also, for robustness, trap data
1593  * access in case something goes wrong in the hat layer and the
1594  * mapping is broken.
1595  */
1596 static int
1597 dump_pagecopy(void *src, void *dst)
1598 {
1599 	long *wsrc = (long *)src;
1600 	long *wdst = (long *)dst;
1601 	const ulong_t ncopies = PAGESIZE / sizeof (long);
1602 	volatile int w = 0;
1603 	volatile int ueoff = -1;
1604 	on_trap_data_t otd;
1605 
1606 	if (on_trap(&otd, OT_DATA_EC | OT_DATA_ACCESS)) {
1607 		if (ueoff == -1)
1608 			ueoff = w * sizeof (long);
1609 		/* report "bad ECC" or "bad address" */
1610 #ifdef _LP64
1611 		if (otd.ot_trap & OT_DATA_EC)
1612 			wdst[w++] = 0x00badecc00badecc;
1613 		else
1614 			wdst[w++] = 0x00badadd00badadd;
1615 #else
1616 		if (otd.ot_trap & OT_DATA_EC)
1617 			wdst[w++] = 0x00badecc;
1618 		else
1619 			wdst[w++] = 0x00badadd;
1620 #endif
1621 	}
1622 	while (w < ncopies) {
1623 		wdst[w] = wsrc[w];
1624 		w++;
1625 	}
1626 	no_trap();
1627 	return (ueoff);
1628 }
1629 
1630 static void
1631 dumpsys_close_cq(cqueue_t *cq, int live)
1632 {
1633 	if (live) {
1634 		mutex_enter(&cq->mutex);
1635 		atomic_dec_uint(&cq->open);
1636 		cv_signal(&cq->cv);
1637 		mutex_exit(&cq->mutex);
1638 	} else {
1639 		atomic_dec_uint(&cq->open);
1640 	}
1641 }
1642 
1643 static inline void
1644 dumpsys_spinlock(lock_t *lp)
1645 {
1646 	uint_t backoff = 0;
1647 	int loop_count = 0;
1648 
1649 	while (LOCK_HELD(lp) || !lock_spin_try(lp)) {
1650 		if (++loop_count >= ncpus) {
1651 			backoff = mutex_lock_backoff(0);
1652 			loop_count = 0;
1653 		} else {
1654 			backoff = mutex_lock_backoff(backoff);
1655 		}
1656 		mutex_lock_delay(backoff);
1657 	}
1658 }
1659 
1660 static inline void
1661 dumpsys_spinunlock(lock_t *lp)
1662 {
1663 	lock_clear(lp);
1664 }
1665 
1666 static inline void
1667 dumpsys_lock(cqueue_t *cq, int live)
1668 {
1669 	if (live)
1670 		mutex_enter(&cq->mutex);
1671 	else
1672 		dumpsys_spinlock(&cq->spinlock);
1673 }
1674 
1675 static inline void
1676 dumpsys_unlock(cqueue_t *cq, int live, int signal)
1677 {
1678 	if (live) {
1679 		if (signal)
1680 			cv_signal(&cq->cv);
1681 		mutex_exit(&cq->mutex);
1682 	} else {
1683 		dumpsys_spinunlock(&cq->spinlock);
1684 	}
1685 }
1686 
1687 static void
1688 dumpsys_wait_cq(cqueue_t *cq, int live)
1689 {
1690 	if (live) {
1691 		cv_wait(&cq->cv, &cq->mutex);
1692 	} else {
1693 		dumpsys_spinunlock(&cq->spinlock);
1694 		while (cq->open)
1695 			if (cq->first)
1696 				break;
1697 		dumpsys_spinlock(&cq->spinlock);
1698 	}
1699 }
1700 
1701 static void
1702 dumpsys_put_cq(cqueue_t *cq, cbuf_t *cp, int newstate, int live)
1703 {
1704 	if (cp == NULL)
1705 		return;
1706 
1707 	dumpsys_lock(cq, live);
1708 
1709 	if (cq->ts != 0) {
1710 		cq->empty += gethrtime() - cq->ts;
1711 		cq->ts = 0;
1712 	}
1713 
1714 	cp->state = newstate;
1715 	cp->next = NULL;
1716 	if (cq->last == NULL)
1717 		cq->first = cp;
1718 	else
1719 		cq->last->next = cp;
1720 	cq->last = cp;
1721 
1722 	dumpsys_unlock(cq, live, 1);
1723 }
1724 
1725 static cbuf_t *
1726 dumpsys_get_cq(cqueue_t *cq, int live)
1727 {
1728 	cbuf_t *cp;
1729 	hrtime_t now = gethrtime();
1730 
1731 	dumpsys_lock(cq, live);
1732 
1733 	/* CONSTCOND */
1734 	while (1) {
1735 		cp = (cbuf_t *)cq->first;
1736 		if (cp == NULL) {
1737 			if (cq->open == 0)
1738 				break;
1739 			dumpsys_wait_cq(cq, live);
1740 			continue;
1741 		}
1742 		cq->first = cp->next;
1743 		if (cq->first == NULL) {
1744 			cq->last = NULL;
1745 			cq->ts = now;
1746 		}
1747 		break;
1748 	}
1749 
1750 	dumpsys_unlock(cq, live, cq->first != NULL || cq->open == 0);
1751 	return (cp);
1752 }
1753 
1754 /*
1755  * Send an error message to the console. If the main task is running
1756  * just write the message via uprintf. If a helper is running the
1757  * message has to be put on a queue for the main task. Setting fmt to
1758  * NULL means flush the error message buffer. If fmt is not NULL, just
1759  * add the text to the existing buffer.
1760  */
1761 static void
1762 dumpsys_errmsg(helper_t *hp, const char *fmt, ...)
1763 {
1764 	dumpsync_t *ds = hp->ds;
1765 	cbuf_t *cp = hp->cperr;
1766 	va_list adx;
1767 
1768 	if (hp->helper == MAINHELPER) {
1769 		if (fmt != NULL) {
1770 			if (ds->neednl) {
1771 				uprintf("\n");
1772 				ds->neednl = 0;
1773 			}
1774 			va_start(adx, fmt);
1775 			vuprintf(fmt, adx);
1776 			va_end(adx);
1777 		}
1778 	} else if (fmt == NULL) {
1779 		if (cp != NULL) {
1780 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1781 			hp->cperr = NULL;
1782 		}
1783 	} else {
1784 		if (hp->cperr == NULL) {
1785 			cp = CQ_GET(freebufq);
1786 			hp->cperr = cp;
1787 			cp->used = 0;
1788 		}
1789 		va_start(adx, fmt);
1790 		cp->used += vsnprintf(cp->buf + cp->used, cp->size - cp->used,
1791 		    fmt, adx);
1792 		va_end(adx);
1793 		if ((cp->used + LOG_MSGSIZE) > cp->size) {
1794 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1795 			hp->cperr = NULL;
1796 		}
1797 	}
1798 }
1799 
1800 /*
1801  * Write an output buffer to the dump file. If the main task is
1802  * running just write the data. If a helper is running the output is
1803  * placed on a queue for the main task.
1804  */
1805 static void
1806 dumpsys_swrite(helper_t *hp, cbuf_t *cp, size_t used)
1807 {
1808 	dumpsync_t *ds = hp->ds;
1809 
1810 	if (hp->helper == MAINHELPER) {
1811 		HRSTART(ds->perpage, write);
1812 		dumpvp_write(cp->buf, used);
1813 		HRSTOP(ds->perpage, write);
1814 		CQ_PUT(freebufq, cp, CBUF_FREEBUF);
1815 	} else {
1816 		cp->used = used;
1817 		CQ_PUT(mainq, cp, CBUF_WRITE);
1818 	}
1819 }
1820 
1821 /*
1822  * Copy one page within the mapped range. The offset starts at 0 and
1823  * is relative to the first pfn. cp->buf + cp->off is the address of
1824  * the first pfn. If dump_pagecopy returns a UE offset, create an
1825  * error message.  Returns the offset to the next pfn in the range
1826  * selected by the bitmap.
1827  */
1828 static int
1829 dumpsys_copy_page(helper_t *hp, int offset)
1830 {
1831 	cbuf_t *cp = hp->cpin;
1832 	int ueoff;
1833 
1834 	ASSERT(cp->off + offset + PAGESIZE <= cp->size);
1835 	ASSERT(BT_TEST(dumpcfg.bitmap, cp->bitnum));
1836 
1837 	ueoff = dump_pagecopy(cp->buf + cp->off + offset, hp->page);
1838 
1839 	/* ueoff is the offset in the page to a UE error */
1840 	if (ueoff != -1) {
1841 		uint64_t pa = ptob(cp->pfn) + offset + ueoff;
1842 
1843 		dumpsys_errmsg(hp, "cpu %d: memory error at PA 0x%08x.%08x\n",
1844 		    CPU->cpu_id, (uint32_t)(pa >> 32), (uint32_t)pa);
1845 	}
1846 
1847 	/*
1848 	 * Advance bitnum and offset to the next input page for the
1849 	 * next call to this function.
1850 	 */
1851 	offset += PAGESIZE;
1852 	cp->bitnum++;
1853 	while (cp->off + offset < cp->size) {
1854 		if (BT_TEST(dumpcfg.bitmap, cp->bitnum))
1855 			break;
1856 		offset += PAGESIZE;
1857 		cp->bitnum++;
1858 	}
1859 
1860 	return (offset);
1861 }
1862 
1863 /*
1864  * Read the helper queue, and copy one mapped page. Return 0 when
1865  * done. Return 1 when a page has been copied into hp->page.
1866  */
1867 static int
1868 dumpsys_sread(helper_t *hp)
1869 {
1870 	dumpsync_t *ds = hp->ds;
1871 
1872 	/* CONSTCOND */
1873 	while (1) {
1874 
1875 		/* Find the next input buffer. */
1876 		if (hp->cpin == NULL) {
1877 			HRSTART(hp->perpage, inwait);
1878 
1879 			/* CONSTCOND */
1880 			while (1) {
1881 				hp->cpin = CQ_GET(helperq);
1882 				dump_timeleft = dump_timeout;
1883 
1884 				/*
1885 				 * NULL return means the helper queue
1886 				 * is closed and empty.
1887 				 */
1888 				if (hp->cpin == NULL)
1889 					break;
1890 
1891 				/* Have input, check for dump I/O error. */
1892 				if (!dump_ioerr)
1893 					break;
1894 
1895 				/*
1896 				 * If an I/O error occurs, stay in the
1897 				 * loop in order to empty the helper
1898 				 * queue. Return the buffers to the
1899 				 * main task to unmap and free it.
1900 				 */
1901 				hp->cpin->used = 0;
1902 				CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1903 			}
1904 			HRSTOP(hp->perpage, inwait);
1905 
1906 			/* Stop here when the helper queue is closed. */
1907 			if (hp->cpin == NULL)
1908 				break;
1909 
1910 			/* Set the offset=0 to get the first pfn. */
1911 			hp->in = 0;
1912 
1913 			/* Set the total processed to 0 */
1914 			hp->used = 0;
1915 		}
1916 
1917 		/* Process the next page. */
1918 		if (hp->used < hp->cpin->used) {
1919 
1920 			/*
1921 			 * Get the next page from the input buffer and
1922 			 * return a copy.
1923 			 */
1924 			ASSERT(hp->in != -1);
1925 			HRSTART(hp->perpage, copy);
1926 			hp->in = dumpsys_copy_page(hp, hp->in);
1927 			hp->used += PAGESIZE;
1928 			HRSTOP(hp->perpage, copy);
1929 			break;
1930 
1931 		} else {
1932 
1933 			/*
1934 			 * Done with the input. Flush the VM and
1935 			 * return the buffer to the main task.
1936 			 */
1937 			if (panicstr && hp->helper != MAINHELPER)
1938 				hat_flush_range(kas.a_hat,
1939 				    hp->cpin->buf, hp->cpin->size);
1940 			dumpsys_errmsg(hp, NULL);
1941 			CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1942 			hp->cpin = NULL;
1943 		}
1944 	}
1945 
1946 	return (hp->cpin != NULL);
1947 }
1948 
1949 /*
1950  * Compress size bytes starting at buf with bzip2
1951  * mode:
1952  *	BZ_RUN		add one more compressed page
1953  *	BZ_FINISH	no more input, flush the state
1954  */
1955 static void
1956 dumpsys_bzrun(helper_t *hp, void *buf, size_t size, int mode)
1957 {
1958 	dumpsync_t *ds = hp->ds;
1959 	const int CSIZE = sizeof (dumpcsize_t);
1960 	bz_stream *ps = &hp->bzstream;
1961 	int rc = 0;
1962 	uint32_t csize;
1963 	dumpcsize_t cs;
1964 
1965 	/* Set input pointers to new input page */
1966 	if (size > 0) {
1967 		ps->avail_in = size;
1968 		ps->next_in = buf;
1969 	}
1970 
1971 	/* CONSTCOND */
1972 	while (1) {
1973 
1974 		/* Quit when all input has been consumed */
1975 		if (ps->avail_in == 0 && mode == BZ_RUN)
1976 			break;
1977 
1978 		/* Get a new output buffer */
1979 		if (hp->cpout == NULL) {
1980 			HRSTART(hp->perpage, outwait);
1981 			hp->cpout = CQ_GET(freebufq);
1982 			HRSTOP(hp->perpage, outwait);
1983 			ps->avail_out = hp->cpout->size - CSIZE;
1984 			ps->next_out = hp->cpout->buf + CSIZE;
1985 		}
1986 
1987 		/* Compress input, or finalize */
1988 		HRSTART(hp->perpage, compress);
1989 		rc = BZ2_bzCompress(ps, mode);
1990 		HRSTOP(hp->perpage, compress);
1991 
1992 		/* Check for error */
1993 		if (mode == BZ_RUN && rc != BZ_RUN_OK) {
1994 			dumpsys_errmsg(hp, "%d: BZ_RUN error %s at page %lx\n",
1995 			    hp->helper, BZ2_bzErrorString(rc),
1996 			    hp->cpin->pagenum);
1997 			break;
1998 		}
1999 
2000 		/* Write the buffer if it is full, or we are flushing */
2001 		if (ps->avail_out == 0 || mode == BZ_FINISH) {
2002 			csize = hp->cpout->size - CSIZE - ps->avail_out;
2003 			cs = DUMP_SET_TAG(csize, hp->tag);
2004 			if (csize > 0) {
2005 				(void) memcpy(hp->cpout->buf, &cs, CSIZE);
2006 				dumpsys_swrite(hp, hp->cpout, csize + CSIZE);
2007 				hp->cpout = NULL;
2008 			}
2009 		}
2010 
2011 		/* Check for final complete */
2012 		if (mode == BZ_FINISH) {
2013 			if (rc == BZ_STREAM_END)
2014 				break;
2015 			if (rc != BZ_FINISH_OK) {
2016 				dumpsys_errmsg(hp, "%d: BZ_FINISH error %s\n",
2017 				    hp->helper, BZ2_bzErrorString(rc));
2018 				break;
2019 			}
2020 		}
2021 	}
2022 
2023 	/* Cleanup state and buffers */
2024 	if (mode == BZ_FINISH) {
2025 
2026 		/* Reset state so that it is re-usable. */
2027 		(void) BZ2_bzCompressReset(&hp->bzstream);
2028 
2029 		/* Give any unused outout buffer to the main task */
2030 		if (hp->cpout != NULL) {
2031 			hp->cpout->used = 0;
2032 			CQ_PUT(mainq, hp->cpout, CBUF_ERRMSG);
2033 			hp->cpout = NULL;
2034 		}
2035 	}
2036 }
2037 
2038 static void
2039 dumpsys_bz2compress(helper_t *hp)
2040 {
2041 	dumpsync_t *ds = hp->ds;
2042 	dumpstreamhdr_t sh;
2043 
2044 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
2045 	sh.stream_pagenum = (pgcnt_t)-1;
2046 	sh.stream_npages = 0;
2047 	hp->cpin = NULL;
2048 	hp->cpout = NULL;
2049 	hp->cperr = NULL;
2050 	hp->in = 0;
2051 	hp->out = 0;
2052 	hp->bzstream.avail_in = 0;
2053 
2054 	/* Bump reference to mainq while we are running */
2055 	CQ_OPEN(mainq);
2056 
2057 	/* Get one page at a time */
2058 	while (dumpsys_sread(hp)) {
2059 		if (sh.stream_pagenum != hp->cpin->pagenum) {
2060 			sh.stream_pagenum = hp->cpin->pagenum;
2061 			sh.stream_npages = btop(hp->cpin->used);
2062 			dumpsys_bzrun(hp, &sh, sizeof (sh), BZ_RUN);
2063 		}
2064 		dumpsys_bzrun(hp, hp->page, PAGESIZE, 0);
2065 	}
2066 
2067 	/* Done with input, flush any partial buffer */
2068 	if (sh.stream_pagenum != (pgcnt_t)-1) {
2069 		dumpsys_bzrun(hp, NULL, 0, BZ_FINISH);
2070 		dumpsys_errmsg(hp, NULL);
2071 	}
2072 
2073 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
2074 
2075 	/* Decrement main queue count, we are done */
2076 	CQ_CLOSE(mainq);
2077 }
2078 
2079 /*
2080  * Compress with lzjb
2081  * write stream block if full or size==0
2082  * if csize==0 write stream header, else write <csize, data>
2083  * size==0 is a call to flush a buffer
2084  * hp->cpout is the buffer we are flushing or filling
2085  * hp->out is the next index to fill data
2086  * osize is either csize+data, or the size of a stream header
2087  */
2088 static void
2089 dumpsys_lzjbrun(helper_t *hp, size_t csize, void *buf, size_t size)
2090 {
2091 	dumpsync_t *ds = hp->ds;
2092 	const int CSIZE = sizeof (dumpcsize_t);
2093 	dumpcsize_t cs;
2094 	size_t osize = csize > 0 ? CSIZE + size : size;
2095 
2096 	/* If flush, and there is no buffer, just return */
2097 	if (size == 0 && hp->cpout == NULL)
2098 		return;
2099 
2100 	/* If flush, or cpout is full, write it out */
2101 	if (size == 0 ||
2102 	    hp->cpout != NULL && hp->out + osize > hp->cpout->size) {
2103 
2104 		/* Set tag+size word at the front of the stream block. */
2105 		cs = DUMP_SET_TAG(hp->out - CSIZE, hp->tag);
2106 		(void) memcpy(hp->cpout->buf, &cs, CSIZE);
2107 
2108 		/* Write block to dump file. */
2109 		dumpsys_swrite(hp, hp->cpout, hp->out);
2110 
2111 		/* Clear pointer to indicate we need a new buffer */
2112 		hp->cpout = NULL;
2113 
2114 		/* flushing, we are done */
2115 		if (size == 0)
2116 			return;
2117 	}
2118 
2119 	/* Get an output buffer if we dont have one. */
2120 	if (hp->cpout == NULL) {
2121 		HRSTART(hp->perpage, outwait);
2122 		hp->cpout = CQ_GET(freebufq);
2123 		HRSTOP(hp->perpage, outwait);
2124 		hp->out = CSIZE;
2125 	}
2126 
2127 	/* Store csize word. This is the size of compressed data. */
2128 	if (csize > 0) {
2129 		cs = DUMP_SET_TAG(csize, 0);
2130 		(void) memcpy(hp->cpout->buf + hp->out, &cs, CSIZE);
2131 		hp->out += CSIZE;
2132 	}
2133 
2134 	/* Store the data. */
2135 	(void) memcpy(hp->cpout->buf + hp->out, buf, size);
2136 	hp->out += size;
2137 }
2138 
2139 static void
2140 dumpsys_lzjbcompress(helper_t *hp)
2141 {
2142 	dumpsync_t *ds = hp->ds;
2143 	size_t csize;
2144 	dumpstreamhdr_t sh;
2145 
2146 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
2147 	sh.stream_pagenum = (pfn_t)-1;
2148 	sh.stream_npages = 0;
2149 	hp->cpin = NULL;
2150 	hp->cpout = NULL;
2151 	hp->cperr = NULL;
2152 	hp->in = 0;
2153 	hp->out = 0;
2154 
2155 	/* Bump reference to mainq while we are running */
2156 	CQ_OPEN(mainq);
2157 
2158 	/* Get one page at a time */
2159 	while (dumpsys_sread(hp)) {
2160 
2161 		/* Create a stream header for each new input map */
2162 		if (sh.stream_pagenum != hp->cpin->pagenum) {
2163 			sh.stream_pagenum = hp->cpin->pagenum;
2164 			sh.stream_npages = btop(hp->cpin->used);
2165 			dumpsys_lzjbrun(hp, 0, &sh, sizeof (sh));
2166 		}
2167 
2168 		/* Compress one page */
2169 		HRSTART(hp->perpage, compress);
2170 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2171 		HRSTOP(hp->perpage, compress);
2172 
2173 		/* Add csize+data to output block */
2174 		ASSERT(csize > 0 && csize <= PAGESIZE);
2175 		dumpsys_lzjbrun(hp, csize, hp->lzbuf, csize);
2176 	}
2177 
2178 	/* Done with input, flush any partial buffer */
2179 	if (sh.stream_pagenum != (pfn_t)-1) {
2180 		dumpsys_lzjbrun(hp, 0, NULL, 0);
2181 		dumpsys_errmsg(hp, NULL);
2182 	}
2183 
2184 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
2185 
2186 	/* Decrement main queue count, we are done */
2187 	CQ_CLOSE(mainq);
2188 }
2189 
2190 /*
2191  * Dump helper called from panic_idle() to compress pages.  CPUs in
2192  * this path must not call most kernel services.
2193  *
2194  * During panic, all but one of the CPUs is idle. These CPUs are used
2195  * as helpers working in parallel to copy and compress memory
2196  * pages. During a panic, however, these processors cannot call any
2197  * kernel services. This is because mutexes become no-ops during
2198  * panic, and, cross-call interrupts are inhibited.  Therefore, during
2199  * panic dump the helper CPUs communicate with the panic CPU using
2200  * memory variables. All memory mapping and I/O is performed by the
2201  * panic CPU.
2202  *
2203  * At dump configuration time, helper_lock is set and helpers_wanted
2204  * is 0. dumpsys() decides whether to set helpers_wanted before
2205  * clearing helper_lock.
2206  *
2207  * At panic time, idle CPUs spin-wait on helper_lock, then alternately
2208  * take the lock and become a helper, or return.
2209  */
2210 void
2211 dumpsys_helper()
2212 {
2213 	dumpsys_spinlock(&dumpcfg.helper_lock);
2214 	if (dumpcfg.helpers_wanted) {
2215 		helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2216 
2217 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2218 			if (hp->helper == FREEHELPER) {
2219 				hp->helper = CPU->cpu_id;
2220 				BT_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2221 
2222 				dumpsys_spinunlock(&dumpcfg.helper_lock);
2223 
2224 				if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2225 					dumpsys_lzjbcompress(hp);
2226 				else
2227 					dumpsys_bz2compress(hp);
2228 
2229 				hp->helper = DONEHELPER;
2230 				return;
2231 			}
2232 		}
2233 
2234 		/* No more helpers are needed. */
2235 		dumpcfg.helpers_wanted = 0;
2236 
2237 	}
2238 	dumpsys_spinunlock(&dumpcfg.helper_lock);
2239 }
2240 
2241 /*
2242  * No-wait helper callable in spin loops.
2243  *
2244  * Do not wait for helper_lock. Just check helpers_wanted. The caller
2245  * may decide to continue. This is the "c)ontinue, s)ync, r)eset? s"
2246  * case.
2247  */
2248 void
2249 dumpsys_helper_nw()
2250 {
2251 	if (dumpcfg.helpers_wanted)
2252 		dumpsys_helper();
2253 }
2254 
2255 /*
2256  * Dump helper for live dumps.
2257  * These run as a system task.
2258  */
2259 static void
2260 dumpsys_live_helper(void *arg)
2261 {
2262 	helper_t *hp = arg;
2263 
2264 	BT_ATOMIC_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2265 	if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2266 		dumpsys_lzjbcompress(hp);
2267 	else
2268 		dumpsys_bz2compress(hp);
2269 }
2270 
2271 /*
2272  * Compress one page with lzjb (single threaded case)
2273  */
2274 static void
2275 dumpsys_lzjb_page(helper_t *hp, cbuf_t *cp)
2276 {
2277 	dumpsync_t *ds = hp->ds;
2278 	uint32_t csize;
2279 
2280 	hp->helper = MAINHELPER;
2281 	hp->in = 0;
2282 	hp->used = 0;
2283 	hp->cpin = cp;
2284 	while (hp->used < cp->used) {
2285 		HRSTART(hp->perpage, copy);
2286 		hp->in = dumpsys_copy_page(hp, hp->in);
2287 		hp->used += PAGESIZE;
2288 		HRSTOP(hp->perpage, copy);
2289 
2290 		HRSTART(hp->perpage, compress);
2291 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2292 		HRSTOP(hp->perpage, compress);
2293 
2294 		HRSTART(hp->perpage, write);
2295 		dumpvp_write(&csize, sizeof (csize));
2296 		dumpvp_write(hp->lzbuf, csize);
2297 		HRSTOP(hp->perpage, write);
2298 	}
2299 	CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
2300 	hp->cpin = NULL;
2301 }
2302 
2303 /*
2304  * Main task to dump pages. This is called on the dump CPU.
2305  */
2306 static void
2307 dumpsys_main_task(void *arg)
2308 {
2309 	dumpsync_t *ds = arg;
2310 	pgcnt_t pagenum = 0, bitnum = 0, hibitnum;
2311 	dumpmlw_t mlw;
2312 	cbuf_t *cp;
2313 	pgcnt_t baseoff, pfnoff;
2314 	pfn_t base, pfn;
2315 	boolean_t dumpserial;
2316 	int i;
2317 
2318 	/*
2319 	 * Fall back to serial mode if there are no helpers.
2320 	 * dump_plat_mincpu can be set to 0 at any time.
2321 	 * dumpcfg.helpermap must contain at least one member.
2322 	 *
2323 	 * It is possible that the helpers haven't registered
2324 	 * in helpermap yet; wait up to DUMP_HELPER_MAX_WAIT for
2325 	 * at least one helper to register.
2326 	 */
2327 	dumpserial = B_TRUE;
2328 	if (dump_plat_mincpu != 0 && dumpcfg.clevel != 0) {
2329 		hrtime_t hrtmax = MSEC2NSEC(DUMP_HELPER_MAX_WAIT);
2330 		hrtime_t hrtstart = gethrtime();
2331 
2332 		for (;;) {
2333 			for (i = 0; i < BT_BITOUL(NCPU); ++i) {
2334 				if (dumpcfg.helpermap[i] != 0) {
2335 					dumpserial = B_FALSE;
2336 					break;
2337 				}
2338 			}
2339 
2340 			if ((!dumpserial) ||
2341 			    ((gethrtime() - hrtstart) >= hrtmax)) {
2342 				break;
2343 			}
2344 
2345 			SMT_PAUSE();
2346 		}
2347 
2348 		if (dumpserial) {
2349 			dumpcfg.clevel = 0;
2350 			if (dumpcfg.helper[0].lzbuf == NULL) {
2351 				dumpcfg.helper[0].lzbuf =
2352 				    dumpcfg.helper[1].page;
2353 			}
2354 		}
2355 	}
2356 
2357 	dump_init_memlist_walker(&mlw);
2358 
2359 	for (;;) {
2360 		int sec = (gethrtime() - ds->start) / NANOSEC;
2361 
2362 		/*
2363 		 * Render a simple progress display on the system console to
2364 		 * make clear to the operator that the system has not hung.
2365 		 * Emit an update when dump progress has advanced by one
2366 		 * percent, or when no update has been drawn in the last
2367 		 * second.
2368 		 */
2369 		if (ds->percent > ds->percent_done || sec > ds->sec_done) {
2370 			ds->sec_done = sec;
2371 			ds->percent_done = ds->percent;
2372 			uprintf("^\rdumping: %2d:%02d %3d%% done",
2373 			    sec / 60, sec % 60, ds->percent);
2374 			ds->neednl = 1;
2375 		}
2376 
2377 		while (CQ_IS_EMPTY(mainq) && !CQ_IS_EMPTY(writerq)) {
2378 
2379 			/* the writerq never blocks */
2380 			cp = CQ_GET(writerq);
2381 			if (cp == NULL)
2382 				break;
2383 
2384 			dump_timeleft = dump_timeout;
2385 
2386 			HRSTART(ds->perpage, write);
2387 			dumpvp_write(cp->buf, cp->used);
2388 			HRSTOP(ds->perpage, write);
2389 
2390 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2391 		}
2392 
2393 		/*
2394 		 * Wait here for some buffers to process. Returns NULL
2395 		 * when all helpers have terminated and all buffers
2396 		 * have been processed.
2397 		 */
2398 		cp = CQ_GET(mainq);
2399 
2400 		if (cp == NULL) {
2401 
2402 			/* Drain the write queue. */
2403 			if (!CQ_IS_EMPTY(writerq))
2404 				continue;
2405 
2406 			/* Main task exits here. */
2407 			break;
2408 		}
2409 
2410 		dump_timeleft = dump_timeout;
2411 
2412 		switch (cp->state) {
2413 
2414 		case CBUF_FREEMAP:
2415 
2416 			/*
2417 			 * Note that we drop CBUF_FREEMAP buffers on
2418 			 * the floor (they will not be on any cqueue)
2419 			 * when we no longer need them.
2420 			 */
2421 			if (bitnum >= dumpcfg.bitmapsize)
2422 				break;
2423 
2424 			if (dump_ioerr) {
2425 				bitnum = dumpcfg.bitmapsize;
2426 				CQ_CLOSE(helperq);
2427 				break;
2428 			}
2429 
2430 			HRSTART(ds->perpage, bitmap);
2431 			for (; bitnum < dumpcfg.bitmapsize; bitnum++)
2432 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2433 					break;
2434 			HRSTOP(ds->perpage, bitmap);
2435 			dump_timeleft = dump_timeout;
2436 
2437 			if (bitnum >= dumpcfg.bitmapsize) {
2438 				CQ_CLOSE(helperq);
2439 				break;
2440 			}
2441 
2442 			/*
2443 			 * Try to map CBUF_MAPSIZE ranges. Can't
2444 			 * assume that memory segment size is a
2445 			 * multiple of CBUF_MAPSIZE. Can't assume that
2446 			 * the segment starts on a CBUF_MAPSIZE
2447 			 * boundary.
2448 			 */
2449 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2450 			ASSERT(pfn != PFN_INVALID);
2451 			ASSERT(bitnum + mlw.mpleft <= dumpcfg.bitmapsize);
2452 
2453 			base = P2ALIGN(pfn, CBUF_MAPNP);
2454 			if (base < mlw.mpaddr) {
2455 				base = mlw.mpaddr;
2456 				baseoff = P2PHASE(base, CBUF_MAPNP);
2457 			} else {
2458 				baseoff = 0;
2459 			}
2460 
2461 			pfnoff = pfn - base;
2462 			if (pfnoff + mlw.mpleft < CBUF_MAPNP) {
2463 				hibitnum = bitnum + mlw.mpleft;
2464 				cp->size = ptob(pfnoff + mlw.mpleft);
2465 			} else {
2466 				hibitnum = bitnum - pfnoff + CBUF_MAPNP -
2467 				    baseoff;
2468 				cp->size = CBUF_MAPSIZE - ptob(baseoff);
2469 			}
2470 
2471 			cp->pfn = pfn;
2472 			cp->bitnum = bitnum++;
2473 			cp->pagenum = pagenum++;
2474 			cp->off = ptob(pfnoff);
2475 
2476 			for (; bitnum < hibitnum; bitnum++)
2477 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2478 					pagenum++;
2479 
2480 			dump_timeleft = dump_timeout;
2481 			cp->used = ptob(pagenum - cp->pagenum);
2482 
2483 			HRSTART(ds->perpage, map);
2484 			hat_devload(kas.a_hat, cp->buf, cp->size, base,
2485 			    PROT_READ, HAT_LOAD_NOCONSIST);
2486 			HRSTOP(ds->perpage, map);
2487 
2488 			ds->pages_mapped += btop(cp->size);
2489 			ds->pages_used += pagenum - cp->pagenum;
2490 
2491 			CQ_OPEN(mainq);
2492 
2493 			/*
2494 			 * If there are no helpers the main task does
2495 			 * non-streams lzjb compress.
2496 			 */
2497 			if (dumpserial) {
2498 				dumpsys_lzjb_page(dumpcfg.helper, cp);
2499 			} else {
2500 				/* pass mapped pages to a helper */
2501 				CQ_PUT(helperq, cp, CBUF_INREADY);
2502 			}
2503 
2504 			/* the last page was done */
2505 			if (bitnum >= dumpcfg.bitmapsize)
2506 				CQ_CLOSE(helperq);
2507 
2508 			break;
2509 
2510 		case CBUF_USEDMAP:
2511 
2512 			ds->npages += btop(cp->used);
2513 
2514 			HRSTART(ds->perpage, unmap);
2515 			hat_unload(kas.a_hat, cp->buf, cp->size, HAT_UNLOAD);
2516 			HRSTOP(ds->perpage, unmap);
2517 
2518 			if (bitnum < dumpcfg.bitmapsize)
2519 				CQ_PUT(mainq, cp, CBUF_FREEMAP);
2520 			CQ_CLOSE(mainq);
2521 
2522 			ASSERT(ds->npages <= dumphdr->dump_npages);
2523 			ds->percent = ds->npages * 100LL / dumphdr->dump_npages;
2524 			break;
2525 
2526 		case CBUF_WRITE:
2527 
2528 			CQ_PUT(writerq, cp, CBUF_WRITE);
2529 			break;
2530 
2531 		case CBUF_ERRMSG:
2532 
2533 			if (cp->used > 0) {
2534 				cp->buf[cp->size - 2] = '\n';
2535 				cp->buf[cp->size - 1] = '\0';
2536 				if (ds->neednl) {
2537 					uprintf("\n%s", cp->buf);
2538 					ds->neednl = 0;
2539 				} else {
2540 					uprintf("%s", cp->buf);
2541 				}
2542 				/* wait for console output */
2543 				drv_usecwait(200000);
2544 				dump_timeleft = dump_timeout;
2545 			}
2546 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2547 			break;
2548 
2549 		default:
2550 			uprintf("dump: unexpected buffer state %d, "
2551 			    "buffer will be lost\n", cp->state);
2552 			break;
2553 
2554 		} /* end switch */
2555 	}
2556 }
2557 
2558 #ifdef	COLLECT_METRICS
2559 size_t
2560 dumpsys_metrics(dumpsync_t *ds, char *buf, size_t size)
2561 {
2562 	dumpcfg_t *cfg = &dumpcfg;
2563 	int myid = CPU->cpu_seqid;
2564 	int i, compress_ratio;
2565 	int sec, iorate;
2566 	helper_t *hp, *hpend = &cfg->helper[cfg->nhelper];
2567 	char *e = buf + size;
2568 	char *p = buf;
2569 
2570 	sec = ds->elapsed / (1000 * 1000 * 1000ULL);
2571 	if (sec < 1)
2572 		sec = 1;
2573 
2574 	if (ds->iotime < 1)
2575 		ds->iotime = 1;
2576 	iorate = (ds->nwrite * 100000ULL) / ds->iotime;
2577 
2578 	compress_ratio = 100LL * ds->npages / btopr(ds->nwrite + 1);
2579 
2580 #define	P(...) (p += p < e ? snprintf(p, e - p, __VA_ARGS__) : 0)
2581 
2582 	P("Master cpu_seqid,%d\n", CPU->cpu_seqid);
2583 	P("Master cpu_id,%d\n", CPU->cpu_id);
2584 	P("dump_flags,0x%x\n", dumphdr->dump_flags);
2585 	P("dump_ioerr,%d\n", dump_ioerr);
2586 
2587 	P("Helpers:\n");
2588 	for (i = 0; i < ncpus; i++) {
2589 		if ((i & 15) == 0)
2590 			P(",,%03d,", i);
2591 		if (i == myid)
2592 			P("   M");
2593 		else if (BT_TEST(cfg->helpermap, i))
2594 			P("%4d", cpu_seq[i]->cpu_id);
2595 		else
2596 			P("   *");
2597 		if ((i & 15) == 15)
2598 			P("\n");
2599 	}
2600 
2601 	P("ncbuf_used,%d\n", cfg->ncbuf_used);
2602 	P("ncmap,%d\n", cfg->ncmap);
2603 
2604 	P("Found %ldM ranges,%ld\n", (CBUF_MAPSIZE / DUMP_1MB), cfg->found4m);
2605 	P("Found small pages,%ld\n", cfg->foundsm);
2606 
2607 	P("Compression level,%d\n", cfg->clevel);
2608 	P("Compression type,%s %s", cfg->clevel == 0 ? "serial" : "parallel",
2609 	    cfg->clevel >= DUMP_CLEVEL_BZIP2 ? "bzip2" : "lzjb");
2610 	if (cfg->clevel >= DUMP_CLEVEL_BZIP2)
2611 		P(" (level %d)\n", dump_bzip2_level);
2612 	else
2613 		P("\n");
2614 	P("Compression ratio,%d.%02d\n", compress_ratio / 100, compress_ratio %
2615 	    100);
2616 	P("nhelper_used,%d\n", cfg->nhelper_used);
2617 
2618 	P("Dump I/O rate MBS,%d.%02d\n", iorate / 100, iorate % 100);
2619 	P("..total bytes,%lld\n", (u_longlong_t)ds->nwrite);
2620 	P("..total nsec,%lld\n", (u_longlong_t)ds->iotime);
2621 	P("dumpbuf.iosize,%ld\n", dumpbuf.iosize);
2622 	P("dumpbuf.size,%ld\n", dumpbuf.size);
2623 
2624 	P("Dump pages/sec,%llu\n", (u_longlong_t)ds->npages / sec);
2625 	P("Dump pages,%llu\n", (u_longlong_t)ds->npages);
2626 	P("Dump time,%d\n", sec);
2627 
2628 	if (ds->pages_mapped > 0)
2629 		P("per-cent map utilization,%d\n", (int)((100 * ds->pages_used)
2630 		    / ds->pages_mapped));
2631 
2632 	P("\nPer-page metrics:\n");
2633 	if (ds->npages > 0) {
2634 		for (hp = cfg->helper; hp != hpend; hp++) {
2635 #define	PERPAGE(x)	ds->perpage.x += hp->perpage.x;
2636 			PERPAGES;
2637 #undef PERPAGE
2638 		}
2639 #define	PERPAGE(x) \
2640 		P("%s nsec/page,%d\n", #x, (int)(ds->perpage.x / ds->npages));
2641 		PERPAGES;
2642 #undef PERPAGE
2643 		P("freebufq.empty,%d\n", (int)(ds->freebufq.empty /
2644 		    ds->npages));
2645 		P("helperq.empty,%d\n", (int)(ds->helperq.empty /
2646 		    ds->npages));
2647 		P("writerq.empty,%d\n", (int)(ds->writerq.empty /
2648 		    ds->npages));
2649 		P("mainq.empty,%d\n", (int)(ds->mainq.empty / ds->npages));
2650 
2651 		P("I/O wait nsec/page,%llu\n", (u_longlong_t)(ds->iowait /
2652 		    ds->npages));
2653 	}
2654 #undef P
2655 	if (p < e)
2656 		bzero(p, e - p);
2657 	return (p - buf);
2658 }
2659 #endif	/* COLLECT_METRICS */
2660 
2661 /*
2662  * Dump the system.
2663  */
2664 void
2665 dumpsys(void)
2666 {
2667 	dumpsync_t *ds = &dumpsync;
2668 	taskq_t *livetaskq = NULL;
2669 	pfn_t pfn;
2670 	pgcnt_t bitnum;
2671 	proc_t *p;
2672 	helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2673 	cbuf_t *cp;
2674 	pid_t npids, pidx;
2675 	char *content;
2676 	char *buf;
2677 	size_t size;
2678 	int save_dump_clevel;
2679 	dumpmlw_t mlw;
2680 	dumpcsize_t datatag;
2681 	dumpdatahdr_t datahdr;
2682 
2683 	if (dumpvp == NULL || dumphdr == NULL) {
2684 		uprintf("skipping system dump - no dump device configured\n");
2685 		if (panicstr) {
2686 			dumpcfg.helpers_wanted = 0;
2687 			dumpsys_spinunlock(&dumpcfg.helper_lock);
2688 		}
2689 		return;
2690 	}
2691 	dumpbuf.cur = dumpbuf.start;
2692 
2693 	/* clear the sync variables */
2694 	ASSERT(dumpcfg.nhelper > 0);
2695 	bzero(ds, sizeof (*ds));
2696 	ds->dumpcpu = CPU->cpu_id;
2697 
2698 	/*
2699 	 * Calculate the starting block for dump.  If we're dumping on a
2700 	 * swap device, start 1/5 of the way in; otherwise, start at the
2701 	 * beginning.  And never use the first page -- it may be a disk label.
2702 	 */
2703 	if (dumpvp->v_flag & VISSWAP)
2704 		dumphdr->dump_start = P2ROUNDUP(dumpvp_size / 5, DUMP_OFFSET);
2705 	else
2706 		dumphdr->dump_start = DUMP_OFFSET;
2707 
2708 	dumphdr->dump_flags = DF_VALID | DF_COMPLETE | DF_LIVE | DF_COMPRESSED;
2709 	dumphdr->dump_crashtime = gethrestime_sec();
2710 	dumphdr->dump_npages = 0;
2711 	dumphdr->dump_nvtop = 0;
2712 	bzero(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.bitmapsize));
2713 	dump_timeleft = dump_timeout;
2714 
2715 	if (panicstr) {
2716 		dumphdr->dump_flags &= ~DF_LIVE;
2717 		(void) VOP_DUMPCTL(dumpvp, DUMP_FREE, NULL, NULL);
2718 		(void) VOP_DUMPCTL(dumpvp, DUMP_ALLOC, NULL, NULL);
2719 		(void) vsnprintf(dumphdr->dump_panicstring, DUMP_PANICSIZE,
2720 		    panicstr, panicargs);
2721 
2722 	}
2723 
2724 	if (dump_conflags & DUMP_ALL)
2725 		content = "all";
2726 	else if (dump_conflags & DUMP_CURPROC)
2727 		content = "kernel + curproc";
2728 	else
2729 		content = "kernel";
2730 	uprintf("dumping to %s, offset %lld, content: %s\n", dumppath,
2731 	    dumphdr->dump_start, content);
2732 
2733 	/* Make sure nodename is current */
2734 	bcopy(utsname.nodename, dumphdr->dump_utsname.nodename, SYS_NMLN);
2735 
2736 	/*
2737 	 * If this is a live dump, try to open a VCHR vnode for better
2738 	 * performance. We must take care to flush the buffer cache
2739 	 * first.
2740 	 */
2741 	if (!panicstr) {
2742 		vnode_t *cdev_vp, *cmn_cdev_vp;
2743 
2744 		ASSERT(dumpbuf.cdev_vp == NULL);
2745 		cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR);
2746 		if (cdev_vp != NULL) {
2747 			cmn_cdev_vp = common_specvp(cdev_vp);
2748 			if (VOP_OPEN(&cmn_cdev_vp, FREAD | FWRITE, kcred, NULL)
2749 			    == 0) {
2750 				if (vn_has_cached_data(dumpvp))
2751 					(void) pvn_vplist_dirty(dumpvp, 0, NULL,
2752 					    B_INVAL | B_TRUNC, kcred);
2753 				dumpbuf.cdev_vp = cmn_cdev_vp;
2754 			} else {
2755 				VN_RELE(cdev_vp);
2756 			}
2757 		}
2758 	}
2759 
2760 	/*
2761 	 * Store a hires timestamp so we can look it up during debugging.
2762 	 */
2763 	lbolt_debug_entry();
2764 
2765 	/*
2766 	 * Leave room for the message and ereport save areas and terminal dump
2767 	 * header.
2768 	 */
2769 	dumpbuf.vp_limit = dumpvp_size - DUMP_LOGSIZE - DUMP_OFFSET -
2770 	    DUMP_ERPTSIZE;
2771 
2772 	/*
2773 	 * Write out the symbol table.  It's no longer compressed,
2774 	 * so its 'size' and 'csize' are equal.
2775 	 */
2776 	dumpbuf.vp_off = dumphdr->dump_ksyms = dumphdr->dump_start + PAGESIZE;
2777 	dumphdr->dump_ksyms_size = dumphdr->dump_ksyms_csize =
2778 	    ksyms_snapshot(dumpvp_ksyms_write, NULL, LONG_MAX);
2779 
2780 	/*
2781 	 * Write out the translation map.
2782 	 */
2783 	dumphdr->dump_map = dumpvp_flush();
2784 	dump_as(&kas);
2785 	dumphdr->dump_nvtop += dump_plat_addr();
2786 
2787 	/*
2788 	 * call into hat, which may have unmapped pages that also need to
2789 	 * be in the dump
2790 	 */
2791 	hat_dump();
2792 
2793 	if (dump_conflags & DUMP_ALL) {
2794 		mutex_enter(&pidlock);
2795 
2796 		for (npids = 0, p = practive; p != NULL; p = p->p_next)
2797 			dumpcfg.pids[npids++] = p->p_pid;
2798 
2799 		mutex_exit(&pidlock);
2800 
2801 		for (pidx = 0; pidx < npids; pidx++)
2802 			(void) dump_process(dumpcfg.pids[pidx]);
2803 
2804 		dump_init_memlist_walker(&mlw);
2805 		for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2806 			dump_timeleft = dump_timeout;
2807 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2808 			/*
2809 			 * Some hypervisors do not have all pages available to
2810 			 * be accessed by the guest OS.  Check for page
2811 			 * accessibility.
2812 			 */
2813 			if (plat_hold_page(pfn, PLAT_HOLD_NO_LOCK, NULL) !=
2814 			    PLAT_HOLD_OK)
2815 				continue;
2816 			BT_SET(dumpcfg.bitmap, bitnum);
2817 		}
2818 		dumphdr->dump_npages = dumpcfg.bitmapsize;
2819 		dumphdr->dump_flags |= DF_ALL;
2820 
2821 	} else if (dump_conflags & DUMP_CURPROC) {
2822 		/*
2823 		 * Determine which pid is to be dumped.  If we're panicking, we
2824 		 * dump the process associated with panic_thread (if any).  If
2825 		 * this is a live dump, we dump the process associated with
2826 		 * curthread.
2827 		 */
2828 		npids = 0;
2829 		if (panicstr) {
2830 			if (panic_thread != NULL &&
2831 			    panic_thread->t_procp != NULL &&
2832 			    panic_thread->t_procp != &p0) {
2833 				dumpcfg.pids[npids++] =
2834 				    panic_thread->t_procp->p_pid;
2835 			}
2836 		} else {
2837 			dumpcfg.pids[npids++] = curthread->t_procp->p_pid;
2838 		}
2839 
2840 		if (npids && dump_process(dumpcfg.pids[0]) == 0)
2841 			dumphdr->dump_flags |= DF_CURPROC;
2842 		else
2843 			dumphdr->dump_flags |= DF_KERNEL;
2844 
2845 	} else {
2846 		dumphdr->dump_flags |= DF_KERNEL;
2847 	}
2848 
2849 	dumphdr->dump_hashmask = (1 << highbit(dumphdr->dump_nvtop - 1)) - 1;
2850 
2851 	/*
2852 	 * Write out the pfn table.
2853 	 */
2854 	dumphdr->dump_pfn = dumpvp_flush();
2855 	dump_init_memlist_walker(&mlw);
2856 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2857 		dump_timeleft = dump_timeout;
2858 		if (!BT_TEST(dumpcfg.bitmap, bitnum))
2859 			continue;
2860 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2861 		ASSERT(pfn != PFN_INVALID);
2862 		dumpvp_write(&pfn, sizeof (pfn_t));
2863 	}
2864 	dump_plat_pfn();
2865 
2866 	/*
2867 	 * Write out all the pages.
2868 	 * Map pages, copy them handling UEs, compress, and write them out.
2869 	 * Cooperate with any helpers running on CPUs in panic_idle().
2870 	 */
2871 	dumphdr->dump_data = dumpvp_flush();
2872 
2873 	bzero(dumpcfg.helpermap, BT_SIZEOFMAP(NCPU));
2874 	ds->live = dumpcfg.clevel > 0 &&
2875 	    (dumphdr->dump_flags & DF_LIVE) != 0;
2876 
2877 	save_dump_clevel = dumpcfg.clevel;
2878 	if (panicstr)
2879 		dumpsys_get_maxmem();
2880 	else if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2881 		dumpcfg.clevel = DUMP_CLEVEL_LZJB;
2882 
2883 	dumpcfg.nhelper_used = 0;
2884 	for (hp = dumpcfg.helper; hp != hpend; hp++) {
2885 		if (hp->page == NULL) {
2886 			hp->helper = DONEHELPER;
2887 			continue;
2888 		}
2889 		++dumpcfg.nhelper_used;
2890 		hp->helper = FREEHELPER;
2891 		hp->taskqid = NULL;
2892 		hp->ds = ds;
2893 		bzero(&hp->perpage, sizeof (hp->perpage));
2894 		if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2895 			(void) BZ2_bzCompressReset(&hp->bzstream);
2896 	}
2897 
2898 	CQ_OPEN(freebufq);
2899 	CQ_OPEN(helperq);
2900 
2901 	dumpcfg.ncbuf_used = 0;
2902 	for (cp = dumpcfg.cbuf; cp != &dumpcfg.cbuf[dumpcfg.ncbuf]; cp++) {
2903 		if (cp->buf != NULL) {
2904 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2905 			++dumpcfg.ncbuf_used;
2906 		}
2907 	}
2908 
2909 	for (cp = dumpcfg.cmap; cp != &dumpcfg.cmap[dumpcfg.ncmap]; cp++)
2910 		CQ_PUT(mainq, cp, CBUF_FREEMAP);
2911 
2912 	ds->start = gethrtime();
2913 	ds->iowaitts = ds->start;
2914 
2915 	/* start helpers */
2916 	if (ds->live) {
2917 		int n = dumpcfg.nhelper_used;
2918 		int pri = MINCLSYSPRI - 25;
2919 
2920 		livetaskq = taskq_create("LiveDump", n, pri, n, n,
2921 		    TASKQ_PREPOPULATE);
2922 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2923 			if (hp->page == NULL)
2924 				continue;
2925 			hp->helper = hp - dumpcfg.helper;
2926 			hp->taskqid = taskq_dispatch(livetaskq,
2927 			    dumpsys_live_helper, (void *)hp, TQ_NOSLEEP);
2928 		}
2929 
2930 	} else {
2931 		if (panicstr)
2932 			kmem_dump_begin();
2933 		dumpcfg.helpers_wanted = dumpcfg.clevel > 0;
2934 		dumpsys_spinunlock(&dumpcfg.helper_lock);
2935 	}
2936 
2937 	/* run main task */
2938 	dumpsys_main_task(ds);
2939 
2940 	ds->elapsed = gethrtime() - ds->start;
2941 	if (ds->elapsed < 1)
2942 		ds->elapsed = 1;
2943 
2944 	if (livetaskq != NULL)
2945 		taskq_destroy(livetaskq);
2946 
2947 	if (ds->neednl) {
2948 		uprintf("\n");
2949 		ds->neednl = 0;
2950 	}
2951 
2952 	/* record actual pages dumped */
2953 	dumphdr->dump_npages = ds->npages;
2954 
2955 	/* platform-specific data */
2956 	dumphdr->dump_npages += dump_plat_data(dumpcfg.cbuf[0].buf);
2957 
2958 	/* note any errors by clearing DF_COMPLETE */
2959 	if (dump_ioerr || ds->npages < dumphdr->dump_npages)
2960 		dumphdr->dump_flags &= ~DF_COMPLETE;
2961 
2962 	/* end of stream blocks */
2963 	datatag = 0;
2964 	dumpvp_write(&datatag, sizeof (datatag));
2965 
2966 	bzero(&datahdr, sizeof (datahdr));
2967 
2968 	/* buffer for metrics */
2969 	buf = dumpcfg.cbuf[0].buf;
2970 	size = MIN(dumpcfg.cbuf[0].size, DUMP_OFFSET - sizeof (dumphdr_t) -
2971 	    sizeof (dumpdatahdr_t));
2972 
2973 	/* finish the kmem intercepts, collect kmem verbose info */
2974 	if (panicstr) {
2975 		datahdr.dump_metrics = kmem_dump_finish(buf, size);
2976 		buf += datahdr.dump_metrics;
2977 		size -= datahdr.dump_metrics;
2978 	}
2979 
2980 	/* record in the header whether this is a fault-management panic */
2981 	if (panicstr)
2982 		dumphdr->dump_fm_panic = is_fm_panic();
2983 
2984 	/* compression info in data header */
2985 	datahdr.dump_datahdr_magic = DUMP_DATAHDR_MAGIC;
2986 	datahdr.dump_datahdr_version = DUMP_DATAHDR_VERSION;
2987 	datahdr.dump_maxcsize = CBUF_SIZE;
2988 	datahdr.dump_maxrange = CBUF_MAPSIZE / PAGESIZE;
2989 	datahdr.dump_nstreams = dumpcfg.nhelper_used;
2990 	datahdr.dump_clevel = dumpcfg.clevel;
2991 #ifdef COLLECT_METRICS
2992 	if (dump_metrics_on)
2993 		datahdr.dump_metrics += dumpsys_metrics(ds, buf, size);
2994 #endif
2995 	datahdr.dump_data_csize = dumpvp_flush() - dumphdr->dump_data;
2996 
2997 	/*
2998 	 * Write out the initial and terminal dump headers.
2999 	 */
3000 	dumpbuf.vp_off = dumphdr->dump_start;
3001 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
3002 	(void) dumpvp_flush();
3003 
3004 	dumpbuf.vp_limit = dumpvp_size;
3005 	dumpbuf.vp_off = dumpbuf.vp_limit - DUMP_OFFSET;
3006 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
3007 	dumpvp_write(&datahdr, sizeof (dumpdatahdr_t));
3008 	dumpvp_write(dumpcfg.cbuf[0].buf, datahdr.dump_metrics);
3009 
3010 	(void) dumpvp_flush();
3011 
3012 	uprintf("\r%3d%% done: %llu pages dumped, ",
3013 	    ds->percent_done, (u_longlong_t)ds->npages);
3014 
3015 	if (dump_ioerr == 0) {
3016 		uprintf("dump succeeded\n");
3017 	} else {
3018 		uprintf("dump failed: error %d\n", dump_ioerr);
3019 #ifdef DEBUG
3020 		if (panicstr)
3021 			debug_enter("dump failed");
3022 #endif
3023 	}
3024 
3025 	/*
3026 	 * Write out all undelivered messages.  This has to be the *last*
3027 	 * thing we do because the dump process itself emits messages.
3028 	 */
3029 	if (panicstr) {
3030 		dump_summary();
3031 		dump_ereports();
3032 		dump_messages();
3033 	}
3034 
3035 	delay(2 * hz);	/* let people see the 'done' message */
3036 	dump_timeleft = 0;
3037 	dump_ioerr = 0;
3038 
3039 	/* restore settings after live dump completes */
3040 	if (!panicstr) {
3041 		dumpcfg.clevel = save_dump_clevel;
3042 
3043 		/* release any VCHR open of the dump device */
3044 		if (dumpbuf.cdev_vp != NULL) {
3045 			(void) VOP_CLOSE(dumpbuf.cdev_vp, FREAD | FWRITE, 1, 0,
3046 			    kcred, NULL);
3047 			VN_RELE(dumpbuf.cdev_vp);
3048 			dumpbuf.cdev_vp = NULL;
3049 		}
3050 	}
3051 }
3052 
3053 /*
3054  * This function is called whenever the memory size, as represented
3055  * by the phys_install list, changes.
3056  */
3057 void
3058 dump_resize()
3059 {
3060 	mutex_enter(&dump_lock);
3061 	dumphdr_init();
3062 	dumpbuf_resize();
3063 	dump_update_clevel();
3064 	mutex_exit(&dump_lock);
3065 }
3066 
3067 /*
3068  * This function allows for dynamic resizing of a dump area. It assumes that
3069  * the underlying device has update its appropriate size(9P).
3070  */
3071 int
3072 dumpvp_resize()
3073 {
3074 	int error;
3075 	vattr_t vattr;
3076 
3077 	mutex_enter(&dump_lock);
3078 	vattr.va_mask = AT_SIZE;
3079 	if ((error = VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL)) != 0) {
3080 		mutex_exit(&dump_lock);
3081 		return (error);
3082 	}
3083 
3084 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE) {
3085 		mutex_exit(&dump_lock);
3086 		return (ENOSPC);
3087 	}
3088 
3089 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
3090 	mutex_exit(&dump_lock);
3091 	return (0);
3092 }
3093 
3094 int
3095 dump_set_uuid(const char *uuidstr)
3096 {
3097 	const char *ptr;
3098 	int i;
3099 
3100 	if (uuidstr == NULL || strnlen(uuidstr, 36 + 1) != 36)
3101 		return (EINVAL);
3102 
3103 	/* uuid_parse is not common code so check manually */
3104 	for (i = 0, ptr = uuidstr; i < 36; i++, ptr++) {
3105 		switch (i) {
3106 		case 8:
3107 		case 13:
3108 		case 18:
3109 		case 23:
3110 			if (*ptr != '-')
3111 				return (EINVAL);
3112 			break;
3113 
3114 		default:
3115 			if (!isxdigit(*ptr))
3116 				return (EINVAL);
3117 			break;
3118 		}
3119 	}
3120 
3121 	if (dump_osimage_uuid[0] != '\0')
3122 		return (EALREADY);
3123 
3124 	(void) strncpy(dump_osimage_uuid, uuidstr, 36 + 1);
3125 
3126 	cmn_err(CE_CONT, "?This Solaris instance has UUID %s\n",
3127 	    dump_osimage_uuid);
3128 
3129 	return (0);
3130 }
3131 
3132 const char *
3133 dump_get_uuid(void)
3134 {
3135 	return (dump_osimage_uuid[0] != '\0' ? dump_osimage_uuid : "");
3136 }
3137