xref: /illumos-gate/usr/src/uts/common/os/dumpsubr.c (revision cd277642e0bdc71a7f57c550df1279b0c091d6e2)
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 2016 Joyent, Inc.
25  */
26 
27 #include <sys/types.h>
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/vm.h>
31 #include <sys/proc.h>
32 #include <sys/file.h>
33 #include <sys/conf.h>
34 #include <sys/kmem.h>
35 #include <sys/mem.h>
36 #include <sys/mman.h>
37 #include <sys/vnode.h>
38 #include <sys/errno.h>
39 #include <sys/memlist.h>
40 #include <sys/dumphdr.h>
41 #include <sys/dumpadm.h>
42 #include <sys/ksyms.h>
43 #include <sys/compress.h>
44 #include <sys/stream.h>
45 #include <sys/strsun.h>
46 #include <sys/cmn_err.h>
47 #include <sys/bitmap.h>
48 #include <sys/modctl.h>
49 #include <sys/utsname.h>
50 #include <sys/systeminfo.h>
51 #include <sys/vmem.h>
52 #include <sys/log.h>
53 #include <sys/var.h>
54 #include <sys/debug.h>
55 #include <sys/sunddi.h>
56 #include <fs/fs_subr.h>
57 #include <sys/fs/snode.h>
58 #include <sys/ontrap.h>
59 #include <sys/panic.h>
60 #include <sys/dkio.h>
61 #include <sys/vtoc.h>
62 #include <sys/errorq.h>
63 #include <sys/fm/util.h>
64 #include <sys/fs/zfs.h>
65 
66 #include <vm/hat.h>
67 #include <vm/as.h>
68 #include <vm/page.h>
69 #include <vm/pvn.h>
70 #include <vm/seg.h>
71 #include <vm/seg_kmem.h>
72 #include <sys/clock_impl.h>
73 #include <sys/hold_page.h>
74 
75 #include <bzip2/bzlib.h>
76 
77 /*
78  * Crash dump time is dominated by disk write time.  To reduce this,
79  * the stronger compression method bzip2 is applied to reduce the dump
80  * size and hence reduce I/O time.  However, bzip2 is much more
81  * computationally expensive than the existing lzjb algorithm, so to
82  * avoid increasing compression time, CPUs that are otherwise idle
83  * during panic are employed to parallelize the compression task.
84  * Many helper CPUs are needed to prevent bzip2 from being a
85  * bottleneck, and on systems with too few CPUs, the lzjb algorithm is
86  * parallelized instead. Lastly, I/O and compression are performed by
87  * different CPUs, and are hence overlapped in time, unlike the older
88  * serial code.
89  *
90  * Another important consideration is the speed of the dump
91  * device. Faster disks need less CPUs in order to benefit from
92  * parallel lzjb versus parallel bzip2. Therefore, the CPU count
93  * threshold for switching from parallel lzjb to paralled bzip2 is
94  * elevated for faster disks. The dump device speed is adduced from
95  * the setting for dumpbuf.iosize, see dump_update_clevel.
96  */
97 
98 /*
99  * exported vars
100  */
101 kmutex_t	dump_lock;		/* lock for dump configuration */
102 dumphdr_t	*dumphdr;		/* dump header */
103 int		dump_conflags = DUMP_KERNEL; /* dump configuration flags */
104 vnode_t		*dumpvp;		/* dump device vnode pointer */
105 u_offset_t	dumpvp_size;		/* size of dump device, in bytes */
106 char		*dumppath;		/* pathname of dump device */
107 int		dump_timeout = 120;	/* timeout for dumping pages */
108 int		dump_timeleft;		/* portion of dump_timeout remaining */
109 int		dump_ioerr;		/* dump i/o error */
110 int		dump_check_used;	/* enable check for used pages */
111 char	    *dump_stack_scratch; /* scratch area for saving stack summary */
112 
113 /*
114  * Tunables for dump compression and parallelism. These can be set via
115  * /etc/system.
116  *
117  * dump_ncpu_low	number of helpers for parallel lzjb
118  *	This is also the minimum configuration.
119  *
120  * dump_bzip2_level	bzip2 compression level: 1-9
121  *	Higher numbers give greater compression, but take more memory
122  *	and time. Memory used per helper is ~(dump_bzip2_level * 1MB).
123  *
124  * dump_plat_mincpu	the cross-over limit for using bzip2 (per platform):
125  *	if dump_plat_mincpu == 0, then always do single threaded dump
126  *	if ncpu >= dump_plat_mincpu then try to use bzip2
127  *
128  * dump_metrics_on	if set, metrics are collected in the kernel, passed
129  *	to savecore via the dump file, and recorded by savecore in
130  *	METRICS.txt.
131  */
132 uint_t dump_ncpu_low = 4;	/* minimum config for parallel lzjb */
133 uint_t dump_bzip2_level = 1;	/* bzip2 level (1-9) */
134 
135 /* Use dump_plat_mincpu_default unless this variable is set by /etc/system */
136 #define	MINCPU_NOT_SET	((uint_t)-1)
137 uint_t dump_plat_mincpu = MINCPU_NOT_SET;
138 
139 /* tunables for pre-reserved heap */
140 uint_t dump_kmem_permap = 1024;
141 uint_t dump_kmem_pages = 8;
142 
143 /* Define multiple buffers per helper to avoid stalling */
144 #define	NCBUF_PER_HELPER	2
145 #define	NCMAP_PER_HELPER	4
146 
147 /* minimum number of helpers configured */
148 #define	MINHELPERS	(dump_ncpu_low)
149 #define	MINCBUFS	(MINHELPERS * NCBUF_PER_HELPER)
150 
151 /*
152  * Define constant parameters.
153  *
154  * CBUF_SIZE		size of an output buffer
155  *
156  * CBUF_MAPSIZE		size of virtual range for mapping pages
157  *
158  * CBUF_MAPNP		size of virtual range in pages
159  *
160  */
161 #define	DUMP_1KB	((size_t)1 << 10)
162 #define	DUMP_1MB	((size_t)1 << 20)
163 #define	CBUF_SIZE	((size_t)1 << 17)
164 #define	CBUF_MAPSHIFT	(22)
165 #define	CBUF_MAPSIZE	((size_t)1 << CBUF_MAPSHIFT)
166 #define	CBUF_MAPNP	((size_t)1 << (CBUF_MAPSHIFT - PAGESHIFT))
167 
168 /*
169  * Compression metrics are accumulated nano-second subtotals. The
170  * results are normalized by the number of pages dumped. A report is
171  * generated when dumpsys() completes and is saved in the dump image
172  * after the trailing dump header.
173  *
174  * Metrics are always collected. Set the variable dump_metrics_on to
175  * cause metrics to be saved in the crash file, where savecore will
176  * save it in the file METRICS.txt.
177  */
178 #define	PERPAGES \
179 	PERPAGE(bitmap) PERPAGE(map) PERPAGE(unmap) \
180 	PERPAGE(copy) PERPAGE(compress) \
181 	PERPAGE(write) \
182 	PERPAGE(inwait) PERPAGE(outwait)
183 
184 typedef struct perpage {
185 #define	PERPAGE(x) hrtime_t x;
186 	PERPAGES
187 #undef PERPAGE
188 } perpage_t;
189 
190 /*
191  * This macro controls the code generation for collecting dump
192  * performance information. By default, the code is generated, but
193  * automatic saving of the information is disabled. If dump_metrics_on
194  * is set to 1, the timing information is passed to savecore via the
195  * crash file, where it is appended to the file dump-dir/METRICS.txt.
196  */
197 #define	COLLECT_METRICS
198 
199 #ifdef COLLECT_METRICS
200 uint_t dump_metrics_on = 0;	/* set to 1 to enable recording metrics */
201 
202 #define	HRSTART(v, m)		v##ts.m = gethrtime()
203 #define	HRSTOP(v, m)		v.m += gethrtime() - v##ts.m
204 #define	HRBEGIN(v, m, s)	v##ts.m = gethrtime(); v.size += s
205 #define	HREND(v, m)		v.m += gethrtime() - v##ts.m
206 #define	HRNORM(v, m, n)		v.m /= (n)
207 
208 #else
209 #define	HRSTART(v, m)
210 #define	HRSTOP(v, m)
211 #define	HRBEGIN(v, m, s)
212 #define	HREND(v, m)
213 #define	HRNORM(v, m, n)
214 #endif	/* COLLECT_METRICS */
215 
216 /*
217  * Buffers for copying and compressing memory pages.
218  *
219  * cbuf_t buffer controllers: used for both input and output.
220  *
221  * The buffer state indicates how it is being used:
222  *
223  * CBUF_FREEMAP: CBUF_MAPSIZE virtual address range is available for
224  * mapping input pages.
225  *
226  * CBUF_INREADY: input pages are mapped and ready for compression by a
227  * helper.
228  *
229  * CBUF_USEDMAP: mapping has been consumed by a helper. Needs unmap.
230  *
231  * CBUF_FREEBUF: CBUF_SIZE output buffer, which is available.
232  *
233  * CBUF_WRITE: CBUF_SIZE block of compressed pages from a helper,
234  * ready to write out.
235  *
236  * CBUF_ERRMSG: CBUF_SIZE block of error messages from a helper
237  * (reports UE errors.)
238  */
239 
240 typedef enum cbufstate {
241 	CBUF_FREEMAP,
242 	CBUF_INREADY,
243 	CBUF_USEDMAP,
244 	CBUF_FREEBUF,
245 	CBUF_WRITE,
246 	CBUF_ERRMSG
247 } cbufstate_t;
248 
249 typedef struct cbuf cbuf_t;
250 
251 struct cbuf {
252 	cbuf_t *next;			/* next in list */
253 	cbufstate_t state;		/* processing state */
254 	size_t used;			/* amount used */
255 	size_t size;			/* mem size */
256 	char *buf;			/* kmem or vmem */
257 	pgcnt_t pagenum;		/* index to pfn map */
258 	pgcnt_t bitnum;			/* first set bitnum */
259 	pfn_t pfn;			/* first pfn in mapped range */
260 	int off;			/* byte offset to first pfn */
261 };
262 
263 static char dump_osimage_uuid[36 + 1];
264 
265 #define	isdigit(ch)	((ch) >= '0' && (ch) <= '9')
266 #define	isxdigit(ch)	(isdigit(ch) || ((ch) >= 'a' && (ch) <= 'f') || \
267 			((ch) >= 'A' && (ch) <= 'F'))
268 
269 /*
270  * cqueue_t queues: a uni-directional channel for communication
271  * from the master to helper tasks or vice-versa using put and
272  * get primitives. Both mappings and data buffers are passed via
273  * queues. Producers close a queue when done. The number of
274  * active producers is reference counted so the consumer can
275  * detect end of data. Concurrent access is mediated by atomic
276  * operations for panic dump, or mutex/cv for live dump.
277  *
278  * There a four queues, used as follows:
279  *
280  * Queue		Dataflow		NewState
281  * --------------------------------------------------
282  * mainq		master -> master	FREEMAP
283  * master has initialized or unmapped an input buffer
284  * --------------------------------------------------
285  * helperq		master -> helper	INREADY
286  * master has mapped input for use by helper
287  * --------------------------------------------------
288  * mainq		master <- helper	USEDMAP
289  * helper is done with input
290  * --------------------------------------------------
291  * freebufq		master -> helper	FREEBUF
292  * master has initialized or written an output buffer
293  * --------------------------------------------------
294  * mainq		master <- helper	WRITE
295  * block of compressed pages from a helper
296  * --------------------------------------------------
297  * mainq		master <- helper	ERRMSG
298  * error messages from a helper (memory error case)
299  * --------------------------------------------------
300  * writerq		master <- master	WRITE
301  * non-blocking queue of blocks to write
302  * --------------------------------------------------
303  */
304 typedef struct cqueue {
305 	cbuf_t *volatile first;		/* first in list */
306 	cbuf_t *last;			/* last in list */
307 	hrtime_t ts;			/* timestamp */
308 	hrtime_t empty;			/* total time empty */
309 	kmutex_t mutex;			/* live state lock */
310 	kcondvar_t cv;			/* live wait var */
311 	lock_t spinlock;		/* panic mode spin lock */
312 	volatile uint_t open;		/* producer ref count */
313 } cqueue_t;
314 
315 /*
316  * Convenience macros for using the cqueue functions
317  * Note that the caller must have defined "dumpsync_t *ds"
318  */
319 #define	CQ_IS_EMPTY(q)					\
320 	(ds->q.first == NULL)
321 
322 #define	CQ_OPEN(q)					\
323 	atomic_inc_uint(&ds->q.open)
324 
325 #define	CQ_CLOSE(q)					\
326 	dumpsys_close_cq(&ds->q, ds->live)
327 
328 #define	CQ_PUT(q, cp, st)				\
329 	dumpsys_put_cq(&ds->q, cp, st, ds->live)
330 
331 #define	CQ_GET(q)					\
332 	dumpsys_get_cq(&ds->q, ds->live)
333 
334 /*
335  * Dynamic state when dumpsys() is running.
336  */
337 typedef struct dumpsync {
338 	pgcnt_t npages;			/* subtotal of pages dumped */
339 	pgcnt_t pages_mapped;		/* subtotal of pages mapped */
340 	pgcnt_t pages_used;		/* subtotal of pages used per map */
341 	size_t nwrite;			/* subtotal of bytes written */
342 	uint_t live;			/* running live dump */
343 	uint_t neednl;			/* will need to print a newline */
344 	uint_t percent;			/* dump progress */
345 	uint_t percent_done;		/* dump progress reported */
346 	int sec_done;			/* dump progress last report time */
347 	cqueue_t freebufq;		/* free kmem bufs for writing */
348 	cqueue_t mainq;			/* input for main task */
349 	cqueue_t helperq;		/* input for helpers */
350 	cqueue_t writerq;		/* input for writer */
351 	hrtime_t start;			/* start time */
352 	hrtime_t elapsed;		/* elapsed time when completed */
353 	hrtime_t iotime;		/* time spent writing nwrite bytes */
354 	hrtime_t iowait;		/* time spent waiting for output */
355 	hrtime_t iowaitts;		/* iowait timestamp */
356 	perpage_t perpage;		/* metrics */
357 	perpage_t perpagets;
358 	int dumpcpu;			/* master cpu */
359 } dumpsync_t;
360 
361 static dumpsync_t dumpsync;		/* synchronization vars */
362 
363 /*
364  * helper_t helpers: contains the context for a stream. CPUs run in
365  * parallel at dump time; each CPU creates a single stream of
366  * compression data.  Stream data is divided into CBUF_SIZE blocks.
367  * The blocks are written in order within a stream. But, blocks from
368  * multiple streams can be interleaved. Each stream is identified by a
369  * unique tag.
370  */
371 typedef struct helper {
372 	int helper;			/* bound helper id */
373 	int tag;			/* compression stream tag */
374 	perpage_t perpage;		/* per page metrics */
375 	perpage_t perpagets;		/* per page metrics (timestamps) */
376 	taskqid_t taskqid;		/* live dump task ptr */
377 	int in, out;			/* buffer offsets */
378 	cbuf_t *cpin, *cpout, *cperr;	/* cbuf objects in process */
379 	dumpsync_t *ds;			/* pointer to sync vars */
380 	size_t used;			/* counts input consumed */
381 	char *page;			/* buffer for page copy */
382 	char *lzbuf;			/* lzjb output */
383 	bz_stream bzstream;		/* bzip2 state */
384 } helper_t;
385 
386 #define	MAINHELPER	(-1)		/* helper is also the main task */
387 #define	FREEHELPER	(-2)		/* unbound helper */
388 #define	DONEHELPER	(-3)		/* helper finished */
389 
390 /*
391  * configuration vars for dumpsys
392  */
393 typedef struct dumpcfg {
394 	int	threshold;	/* ncpu threshold for bzip2 */
395 	int	nhelper;	/* number of helpers */
396 	int	nhelper_used;	/* actual number of helpers used */
397 	int	ncmap;		/* number VA pages for compression */
398 	int	ncbuf;		/* number of bufs for compression */
399 	int	ncbuf_used;	/* number of bufs in use */
400 	uint_t	clevel;		/* dump compression level */
401 	helper_t *helper;	/* array of helpers */
402 	cbuf_t	*cmap;		/* array of input (map) buffers */
403 	cbuf_t	*cbuf;		/* array of output  buffers */
404 	ulong_t	*helpermap;	/* set of dumpsys helper CPU ids */
405 	ulong_t	*bitmap;	/* bitmap for marking pages to dump */
406 	ulong_t	*rbitmap;	/* bitmap for used CBUF_MAPSIZE ranges */
407 	pgcnt_t	bitmapsize;	/* size of bitmap */
408 	pgcnt_t	rbitmapsize;	/* size of bitmap for ranges */
409 	pgcnt_t found4m;	/* number ranges allocated by dump */
410 	pgcnt_t foundsm;	/* number small pages allocated by dump */
411 	pid_t	*pids;		/* list of process IDs at dump time */
412 	size_t	maxsize;	/* memory size needed at dump time */
413 	size_t	maxvmsize;	/* size of reserved VM */
414 	char	*maxvm;		/* reserved VM for spare pages */
415 	lock_t	helper_lock;	/* protect helper state */
416 	char	helpers_wanted;	/* flag to enable parallelism */
417 } dumpcfg_t;
418 
419 static dumpcfg_t dumpcfg;	/* config vars */
420 
421 /*
422  * The dump I/O buffer.
423  *
424  * There is one I/O buffer used by dumpvp_write and dumvp_flush. It is
425  * sized according to the optimum device transfer speed.
426  */
427 typedef struct dumpbuf {
428 	vnode_t	*cdev_vp;	/* VCHR open of the dump device */
429 	len_t	vp_limit;	/* maximum write offset */
430 	offset_t vp_off;	/* current dump device offset */
431 	char	*cur;		/* dump write pointer */
432 	char	*start;		/* dump buffer address */
433 	char	*end;		/* dump buffer end */
434 	size_t	size;		/* size of dumpbuf in bytes */
435 	size_t	iosize;		/* best transfer size for device */
436 } dumpbuf_t;
437 
438 dumpbuf_t dumpbuf;		/* I/O buffer */
439 
440 /*
441  * The dump I/O buffer must be at least one page, at most xfer_size
442  * bytes, and should scale with physmem in between.  The transfer size
443  * passed in will either represent a global default (maxphys) or the
444  * best size for the device.  The size of the dumpbuf I/O buffer is
445  * limited by dumpbuf_limit (8MB by default) because the dump
446  * performance saturates beyond a certain size.  The default is to
447  * select 1/4096 of the memory.
448  */
449 static int	dumpbuf_fraction = 12;	/* memory size scale factor */
450 static size_t	dumpbuf_limit = 8 * DUMP_1MB;	/* max I/O buf size */
451 
452 static size_t
453 dumpbuf_iosize(size_t xfer_size)
454 {
455 	size_t iosize = ptob(physmem >> dumpbuf_fraction);
456 
457 	if (iosize < PAGESIZE)
458 		iosize = PAGESIZE;
459 	else if (iosize > xfer_size)
460 		iosize = xfer_size;
461 	if (iosize > dumpbuf_limit)
462 		iosize = dumpbuf_limit;
463 	return (iosize & PAGEMASK);
464 }
465 
466 /*
467  * resize the I/O buffer
468  */
469 static void
470 dumpbuf_resize(void)
471 {
472 	char *old_buf = dumpbuf.start;
473 	size_t old_size = dumpbuf.size;
474 	char *new_buf;
475 	size_t new_size;
476 
477 	ASSERT(MUTEX_HELD(&dump_lock));
478 
479 	new_size = dumpbuf_iosize(MAX(dumpbuf.iosize, maxphys));
480 	if (new_size <= old_size)
481 		return; /* no need to reallocate buffer */
482 
483 	new_buf = kmem_alloc(new_size, KM_SLEEP);
484 	dumpbuf.size = new_size;
485 	dumpbuf.start = new_buf;
486 	dumpbuf.end = new_buf + new_size;
487 	kmem_free(old_buf, old_size);
488 }
489 
490 /*
491  * dump_update_clevel is called when dumpadm configures the dump device.
492  * 	Calculate number of helpers and buffers.
493  * 	Allocate the minimum configuration for now.
494  *
495  * When the dump file is configured we reserve a minimum amount of
496  * memory for use at crash time. But we reserve VA for all the memory
497  * we really want in order to do the fastest dump possible. The VA is
498  * backed by pages not being dumped, according to the bitmap. If
499  * there is insufficient spare memory, however, we fall back to the
500  * minimum.
501  *
502  * Live dump (savecore -L) always uses the minimum config.
503  *
504  * clevel 0 is single threaded lzjb
505  * clevel 1 is parallel lzjb
506  * clevel 2 is parallel bzip2
507  *
508  * The ncpu threshold is selected with dump_plat_mincpu.
509  * On OPL, set_platform_defaults() overrides the sun4u setting.
510  * The actual values are defined via DUMP_PLAT_*_MINCPU macros.
511  *
512  * Architecture		Threshold	Algorithm
513  * sun4u       		<  51		parallel lzjb
514  * sun4u       		>= 51		parallel bzip2(*)
515  * sun4u OPL   		<  8		parallel lzjb
516  * sun4u OPL   		>= 8		parallel bzip2(*)
517  * sun4v       		<  128		parallel lzjb
518  * sun4v       		>= 128		parallel bzip2(*)
519  * x86			< 11		parallel lzjb
520  * x86			>= 11		parallel bzip2(*)
521  * 32-bit      		N/A		single-threaded lzjb
522  *
523  * (*) bzip2 is only chosen if there is sufficient available
524  * memory for buffers at dump time. See dumpsys_get_maxmem().
525  *
526  * Faster dump devices have larger I/O buffers. The threshold value is
527  * increased according to the size of the dump I/O buffer, because
528  * parallel lzjb performs better with faster disks. For buffers >= 1MB
529  * the threshold is 3X; for buffers >= 256K threshold is 2X.
530  *
531  * For parallel dumps, the number of helpers is ncpu-1. The CPU
532  * running panic runs the main task. For single-threaded dumps, the
533  * panic CPU does lzjb compression (it is tagged as MAINHELPER.)
534  *
535  * Need multiple buffers per helper so that they do not block waiting
536  * for the main task.
537  *				parallel	single-threaded
538  * Number of output buffers:	nhelper*2		1
539  * Number of mapping buffers:	nhelper*4		1
540  *
541  */
542 static void
543 dump_update_clevel()
544 {
545 	int tag;
546 	size_t bz2size;
547 	helper_t *hp, *hpend;
548 	cbuf_t *cp, *cpend;
549 	dumpcfg_t *old = &dumpcfg;
550 	dumpcfg_t newcfg = *old;
551 	dumpcfg_t *new = &newcfg;
552 
553 	ASSERT(MUTEX_HELD(&dump_lock));
554 
555 	/*
556 	 * Free the previously allocated bufs and VM.
557 	 */
558 	if (old->helper != NULL) {
559 
560 		/* helpers */
561 		hpend = &old->helper[old->nhelper];
562 		for (hp = old->helper; hp != hpend; hp++) {
563 			if (hp->lzbuf != NULL)
564 				kmem_free(hp->lzbuf, PAGESIZE);
565 			if (hp->page != NULL)
566 				kmem_free(hp->page, PAGESIZE);
567 		}
568 		kmem_free(old->helper, old->nhelper * sizeof (helper_t));
569 
570 		/* VM space for mapping pages */
571 		cpend = &old->cmap[old->ncmap];
572 		for (cp = old->cmap; cp != cpend; cp++)
573 			vmem_xfree(heap_arena, cp->buf, CBUF_MAPSIZE);
574 		kmem_free(old->cmap, old->ncmap * sizeof (cbuf_t));
575 
576 		/* output bufs */
577 		cpend = &old->cbuf[old->ncbuf];
578 		for (cp = old->cbuf; cp != cpend; cp++)
579 			if (cp->buf != NULL)
580 				kmem_free(cp->buf, cp->size);
581 		kmem_free(old->cbuf, old->ncbuf * sizeof (cbuf_t));
582 
583 		/* reserved VM for dumpsys_get_maxmem */
584 		if (old->maxvmsize > 0)
585 			vmem_xfree(heap_arena, old->maxvm, old->maxvmsize);
586 	}
587 
588 	/*
589 	 * Allocate memory and VM.
590 	 * One CPU runs dumpsys, the rest are helpers.
591 	 */
592 	new->nhelper = ncpus - 1;
593 	if (new->nhelper < 1)
594 		new->nhelper = 1;
595 
596 	if (new->nhelper > DUMP_MAX_NHELPER)
597 		new->nhelper = DUMP_MAX_NHELPER;
598 
599 	/* use platform default, unless /etc/system overrides */
600 	if (dump_plat_mincpu == MINCPU_NOT_SET)
601 		dump_plat_mincpu = dump_plat_mincpu_default;
602 
603 	/* increase threshold for faster disks */
604 	new->threshold = dump_plat_mincpu;
605 	if (dumpbuf.iosize >= DUMP_1MB)
606 		new->threshold *= 3;
607 	else if (dumpbuf.iosize >= (256 * DUMP_1KB))
608 		new->threshold *= 2;
609 
610 	/* figure compression level based upon the computed threshold. */
611 	if (dump_plat_mincpu == 0 || new->nhelper < 2) {
612 		new->clevel = 0;
613 		new->nhelper = 1;
614 	} else if ((new->nhelper + 1) >= new->threshold) {
615 		new->clevel = DUMP_CLEVEL_BZIP2;
616 	} else {
617 		new->clevel = DUMP_CLEVEL_LZJB;
618 	}
619 
620 	if (new->clevel == 0) {
621 		new->ncbuf = 1;
622 		new->ncmap = 1;
623 	} else {
624 		new->ncbuf = NCBUF_PER_HELPER * new->nhelper;
625 		new->ncmap = NCMAP_PER_HELPER * new->nhelper;
626 	}
627 
628 	/*
629 	 * Allocate new data structures and buffers for MINHELPERS,
630 	 * and also figure the max desired size.
631 	 */
632 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
633 	new->maxsize = 0;
634 	new->maxvmsize = 0;
635 	new->maxvm = NULL;
636 	tag = 1;
637 	new->helper = kmem_zalloc(new->nhelper * sizeof (helper_t), KM_SLEEP);
638 	hpend = &new->helper[new->nhelper];
639 	for (hp = new->helper; hp != hpend; hp++) {
640 		hp->tag = tag++;
641 		if (hp < &new->helper[MINHELPERS]) {
642 			hp->lzbuf = kmem_alloc(PAGESIZE, KM_SLEEP);
643 			hp->page = kmem_alloc(PAGESIZE, KM_SLEEP);
644 		} else if (new->clevel < DUMP_CLEVEL_BZIP2) {
645 			new->maxsize += 2 * PAGESIZE;
646 		} else {
647 			new->maxsize += PAGESIZE;
648 		}
649 		if (new->clevel >= DUMP_CLEVEL_BZIP2)
650 			new->maxsize += bz2size;
651 	}
652 
653 	new->cbuf = kmem_zalloc(new->ncbuf * sizeof (cbuf_t), KM_SLEEP);
654 	cpend = &new->cbuf[new->ncbuf];
655 	for (cp = new->cbuf; cp != cpend; cp++) {
656 		cp->state = CBUF_FREEBUF;
657 		cp->size = CBUF_SIZE;
658 		if (cp < &new->cbuf[MINCBUFS])
659 			cp->buf = kmem_alloc(cp->size, KM_SLEEP);
660 		else
661 			new->maxsize += cp->size;
662 	}
663 
664 	new->cmap = kmem_zalloc(new->ncmap * sizeof (cbuf_t), KM_SLEEP);
665 	cpend = &new->cmap[new->ncmap];
666 	for (cp = new->cmap; cp != cpend; cp++) {
667 		cp->state = CBUF_FREEMAP;
668 		cp->size = CBUF_MAPSIZE;
669 		cp->buf = vmem_xalloc(heap_arena, CBUF_MAPSIZE, CBUF_MAPSIZE,
670 		    0, 0, NULL, NULL, VM_SLEEP);
671 	}
672 
673 	/* reserve VA to be backed with spare pages at crash time */
674 	if (new->maxsize > 0) {
675 		new->maxsize = P2ROUNDUP(new->maxsize, PAGESIZE);
676 		new->maxvmsize = P2ROUNDUP(new->maxsize, CBUF_MAPSIZE);
677 		new->maxvm = vmem_xalloc(heap_arena, new->maxvmsize,
678 		    CBUF_MAPSIZE, 0, 0, NULL, NULL, VM_SLEEP);
679 	}
680 
681 	/*
682 	 * Reserve memory for kmem allocation calls made during crash
683 	 * dump.  The hat layer allocates memory for each mapping
684 	 * created, and the I/O path allocates buffers and data structs.
685 	 * Add a few pages for safety.
686 	 */
687 	kmem_dump_init((new->ncmap * dump_kmem_permap) +
688 	    (dump_kmem_pages * PAGESIZE));
689 
690 	/* set new config pointers */
691 	*old = *new;
692 }
693 
694 /*
695  * Define a struct memlist walker to optimize bitnum to pfn
696  * lookup. The walker maintains the state of the list traversal.
697  */
698 typedef struct dumpmlw {
699 	struct memlist	*mp;		/* current memlist */
700 	pgcnt_t		basenum;	/* bitnum base offset */
701 	pgcnt_t		mppages;	/* current memlist size */
702 	pgcnt_t		mpleft;		/* size to end of current memlist */
703 	pfn_t		mpaddr;		/* first pfn in memlist */
704 } dumpmlw_t;
705 
706 /* initialize the walker */
707 static inline void
708 dump_init_memlist_walker(dumpmlw_t *pw)
709 {
710 	pw->mp = phys_install;
711 	pw->basenum = 0;
712 	pw->mppages = pw->mp->ml_size >> PAGESHIFT;
713 	pw->mpleft = pw->mppages;
714 	pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
715 }
716 
717 /*
718  * Lookup pfn given bitnum. The memlist can be quite long on some
719  * systems (e.g.: one per board). To optimize sequential lookups, the
720  * caller initializes and presents a memlist walker.
721  */
722 static pfn_t
723 dump_bitnum_to_pfn(pgcnt_t bitnum, dumpmlw_t *pw)
724 {
725 	bitnum -= pw->basenum;
726 	while (pw->mp != NULL) {
727 		if (bitnum < pw->mppages) {
728 			pw->mpleft = pw->mppages - bitnum;
729 			return (pw->mpaddr + bitnum);
730 		}
731 		bitnum -= pw->mppages;
732 		pw->basenum += pw->mppages;
733 		pw->mp = pw->mp->ml_next;
734 		if (pw->mp != NULL) {
735 			pw->mppages = pw->mp->ml_size >> PAGESHIFT;
736 			pw->mpleft = pw->mppages;
737 			pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
738 		}
739 	}
740 	return (PFN_INVALID);
741 }
742 
743 static pgcnt_t
744 dump_pfn_to_bitnum(pfn_t pfn)
745 {
746 	struct memlist *mp;
747 	pgcnt_t bitnum = 0;
748 
749 	for (mp = phys_install; mp != NULL; mp = mp->ml_next) {
750 		if (pfn >= (mp->ml_address >> PAGESHIFT) &&
751 		    pfn < ((mp->ml_address + mp->ml_size) >> PAGESHIFT))
752 			return (bitnum + pfn - (mp->ml_address >> PAGESHIFT));
753 		bitnum += mp->ml_size >> PAGESHIFT;
754 	}
755 	return ((pgcnt_t)-1);
756 }
757 
758 /*
759  * Set/test bitmap for a CBUF_MAPSIZE range which includes pfn. The
760  * mapping of pfn to range index is imperfect because pfn and bitnum
761  * do not have the same phase. To make sure a CBUF_MAPSIZE range is
762  * covered, call this for both ends:
763  *	dump_set_used(base)
764  *	dump_set_used(base+CBUF_MAPNP-1)
765  *
766  * This is used during a panic dump to mark pages allocated by
767  * dumpsys_get_maxmem(). The macro IS_DUMP_PAGE(pp) is used by
768  * page_get_mnode_freelist() to make sure pages used by dump are never
769  * allocated.
770  */
771 #define	CBUF_MAPP2R(pfn)	((pfn) >> (CBUF_MAPSHIFT - PAGESHIFT))
772 
773 static void
774 dump_set_used(pfn_t pfn)
775 {
776 
777 	pgcnt_t bitnum, rbitnum;
778 
779 	bitnum = dump_pfn_to_bitnum(pfn);
780 	ASSERT(bitnum != (pgcnt_t)-1);
781 
782 	rbitnum = CBUF_MAPP2R(bitnum);
783 	ASSERT(rbitnum < dumpcfg.rbitmapsize);
784 
785 	BT_SET(dumpcfg.rbitmap, rbitnum);
786 }
787 
788 int
789 dump_test_used(pfn_t pfn)
790 {
791 	pgcnt_t bitnum, rbitnum;
792 
793 	bitnum = dump_pfn_to_bitnum(pfn);
794 	ASSERT(bitnum != (pgcnt_t)-1);
795 
796 	rbitnum = CBUF_MAPP2R(bitnum);
797 	ASSERT(rbitnum < dumpcfg.rbitmapsize);
798 
799 	return (BT_TEST(dumpcfg.rbitmap, rbitnum));
800 }
801 
802 /*
803  * dumpbzalloc and dumpbzfree are callbacks from the bzip2 library.
804  * dumpsys_get_maxmem() uses them for BZ2_bzCompressInit().
805  */
806 static void *
807 dumpbzalloc(void *opaque, int items, int size)
808 {
809 	size_t *sz;
810 	char *ret;
811 
812 	ASSERT(opaque != NULL);
813 	sz = opaque;
814 	ret = dumpcfg.maxvm + *sz;
815 	*sz += items * size;
816 	*sz = P2ROUNDUP(*sz, BZ2_BZALLOC_ALIGN);
817 	ASSERT(*sz <= dumpcfg.maxvmsize);
818 	return (ret);
819 }
820 
821 /*ARGSUSED*/
822 static void
823 dumpbzfree(void *opaque, void *addr)
824 {
825 }
826 
827 /*
828  * Perform additional checks on the page to see if we can really use
829  * it. The kernel (kas) pages are always set in the bitmap. However,
830  * boot memory pages (prom_ppages or P_BOOTPAGES) are not in the
831  * bitmap. So we check for them.
832  */
833 static inline int
834 dump_pfn_check(pfn_t pfn)
835 {
836 	page_t *pp = page_numtopp_nolock(pfn);
837 	if (pp == NULL || pp->p_pagenum != pfn ||
838 #if defined(__sparc)
839 	    pp->p_vnode == &promvp ||
840 #else
841 	    PP_ISBOOTPAGES(pp) ||
842 #endif
843 	    pp->p_toxic != 0)
844 		return (0);
845 	return (1);
846 }
847 
848 /*
849  * Check a range to see if all contained pages are available and
850  * return non-zero if the range can be used.
851  */
852 static inline int
853 dump_range_check(pgcnt_t start, pgcnt_t end, pfn_t pfn)
854 {
855 	for (; start < end; start++, pfn++) {
856 		if (BT_TEST(dumpcfg.bitmap, start))
857 			return (0);
858 		if (!dump_pfn_check(pfn))
859 			return (0);
860 	}
861 	return (1);
862 }
863 
864 /*
865  * dumpsys_get_maxmem() is called during panic. Find unused ranges
866  * and use them for buffers. If we find enough memory switch to
867  * parallel bzip2, otherwise use parallel lzjb.
868  *
869  * It searches the dump bitmap in 2 passes. The first time it looks
870  * for CBUF_MAPSIZE ranges. On the second pass it uses small pages.
871  */
872 static void
873 dumpsys_get_maxmem()
874 {
875 	dumpcfg_t *cfg = &dumpcfg;
876 	cbuf_t *endcp = &cfg->cbuf[cfg->ncbuf];
877 	helper_t *endhp = &cfg->helper[cfg->nhelper];
878 	pgcnt_t bitnum, end;
879 	size_t sz, endsz, bz2size;
880 	pfn_t pfn, off;
881 	cbuf_t *cp;
882 	helper_t *hp, *ohp;
883 	dumpmlw_t mlw;
884 	int k;
885 
886 	/*
887 	 * Setting dump_plat_mincpu to 0 at any time forces a serial
888 	 * dump.
889 	 */
890 	if (dump_plat_mincpu == 0) {
891 		cfg->clevel = 0;
892 		return;
893 	}
894 
895 	/*
896 	 * There may be no point in looking for spare memory. If
897 	 * dumping all memory, then none is spare. If doing a serial
898 	 * dump, then already have buffers.
899 	 */
900 	if (cfg->maxsize == 0 || cfg->clevel < DUMP_CLEVEL_LZJB ||
901 	    (dump_conflags & DUMP_ALL) != 0) {
902 		if (cfg->clevel > DUMP_CLEVEL_LZJB)
903 			cfg->clevel = DUMP_CLEVEL_LZJB;
904 		return;
905 	}
906 
907 	sz = 0;
908 	cfg->found4m = 0;
909 	cfg->foundsm = 0;
910 
911 	/* bitmap of ranges used to estimate which pfns are being used */
912 	bzero(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.rbitmapsize));
913 
914 	/* find ranges that are not being dumped to use for buffers */
915 	dump_init_memlist_walker(&mlw);
916 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
917 		dump_timeleft = dump_timeout;
918 		end = bitnum + CBUF_MAPNP;
919 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
920 		ASSERT(pfn != PFN_INVALID);
921 
922 		/* skip partial range at end of mem segment */
923 		if (mlw.mpleft < CBUF_MAPNP) {
924 			end = bitnum + mlw.mpleft;
925 			continue;
926 		}
927 
928 		/* skip non aligned pages */
929 		off = P2PHASE(pfn, CBUF_MAPNP);
930 		if (off != 0) {
931 			end -= off;
932 			continue;
933 		}
934 
935 		if (!dump_range_check(bitnum, end, pfn))
936 			continue;
937 
938 		ASSERT((sz + CBUF_MAPSIZE) <= cfg->maxvmsize);
939 		hat_devload(kas.a_hat, cfg->maxvm + sz, CBUF_MAPSIZE, pfn,
940 		    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
941 		sz += CBUF_MAPSIZE;
942 		cfg->found4m++;
943 
944 		/* set the bitmap for both ends to be sure to cover the range */
945 		dump_set_used(pfn);
946 		dump_set_used(pfn + CBUF_MAPNP - 1);
947 
948 		if (sz >= cfg->maxsize)
949 			goto foundmax;
950 	}
951 
952 	/* Add small pages if we can't find enough large pages. */
953 	dump_init_memlist_walker(&mlw);
954 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
955 		dump_timeleft = dump_timeout;
956 		end = bitnum + CBUF_MAPNP;
957 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
958 		ASSERT(pfn != PFN_INVALID);
959 
960 		/* Find any non-aligned pages at start and end of segment. */
961 		off = P2PHASE(pfn, CBUF_MAPNP);
962 		if (mlw.mpleft < CBUF_MAPNP) {
963 			end = bitnum + mlw.mpleft;
964 		} else if (off != 0) {
965 			end -= off;
966 		} else if (cfg->found4m && dump_test_used(pfn)) {
967 			continue;
968 		}
969 
970 		for (; bitnum < end; bitnum++, pfn++) {
971 			dump_timeleft = dump_timeout;
972 			if (BT_TEST(dumpcfg.bitmap, bitnum))
973 				continue;
974 			if (!dump_pfn_check(pfn))
975 				continue;
976 			ASSERT((sz + PAGESIZE) <= cfg->maxvmsize);
977 			hat_devload(kas.a_hat, cfg->maxvm + sz, PAGESIZE, pfn,
978 			    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
979 			sz += PAGESIZE;
980 			cfg->foundsm++;
981 			dump_set_used(pfn);
982 			if (sz >= cfg->maxsize)
983 				goto foundmax;
984 		}
985 	}
986 
987 	/* Fall back to lzjb if we did not get enough memory for bzip2. */
988 	endsz = (cfg->maxsize * cfg->threshold) / cfg->nhelper;
989 	if (sz < endsz) {
990 		cfg->clevel = DUMP_CLEVEL_LZJB;
991 	}
992 
993 	/* Allocate memory for as many helpers as we can. */
994 foundmax:
995 
996 	/* Byte offsets into memory found and mapped above */
997 	endsz = sz;
998 	sz = 0;
999 
1000 	/* Set the size for bzip2 state. Only bzip2 needs it. */
1001 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
1002 
1003 	/* Skip the preallocate output buffers. */
1004 	cp = &cfg->cbuf[MINCBUFS];
1005 
1006 	/* Use this to move memory up from the preallocated helpers. */
1007 	ohp = cfg->helper;
1008 
1009 	/* Loop over all helpers and allocate memory. */
1010 	for (hp = cfg->helper; hp < endhp; hp++) {
1011 
1012 		/* Skip preallocated helpers by checking hp->page. */
1013 		if (hp->page == NULL) {
1014 			if (cfg->clevel <= DUMP_CLEVEL_LZJB) {
1015 				/* lzjb needs 2 1-page buffers */
1016 				if ((sz + (2 * PAGESIZE)) > endsz)
1017 					break;
1018 				hp->page = cfg->maxvm + sz;
1019 				sz += PAGESIZE;
1020 				hp->lzbuf = cfg->maxvm + sz;
1021 				sz += PAGESIZE;
1022 
1023 			} else if (ohp->lzbuf != NULL) {
1024 				/* re-use the preallocted lzjb page for bzip2 */
1025 				hp->page = ohp->lzbuf;
1026 				ohp->lzbuf = NULL;
1027 				++ohp;
1028 
1029 			} else {
1030 				/* bzip2 needs a 1-page buffer */
1031 				if ((sz + PAGESIZE) > endsz)
1032 					break;
1033 				hp->page = cfg->maxvm + sz;
1034 				sz += PAGESIZE;
1035 			}
1036 		}
1037 
1038 		/*
1039 		 * Add output buffers per helper. The number of
1040 		 * buffers per helper is determined by the ratio of
1041 		 * ncbuf to nhelper.
1042 		 */
1043 		for (k = 0; cp < endcp && (sz + CBUF_SIZE) <= endsz &&
1044 		    k < NCBUF_PER_HELPER; k++) {
1045 			cp->state = CBUF_FREEBUF;
1046 			cp->size = CBUF_SIZE;
1047 			cp->buf = cfg->maxvm + sz;
1048 			sz += CBUF_SIZE;
1049 			++cp;
1050 		}
1051 
1052 		/*
1053 		 * bzip2 needs compression state. Use the dumpbzalloc
1054 		 * and dumpbzfree callbacks to allocate the memory.
1055 		 * bzip2 does allocation only at init time.
1056 		 */
1057 		if (cfg->clevel >= DUMP_CLEVEL_BZIP2) {
1058 			if ((sz + bz2size) > endsz) {
1059 				hp->page = NULL;
1060 				break;
1061 			} else {
1062 				hp->bzstream.opaque = &sz;
1063 				hp->bzstream.bzalloc = dumpbzalloc;
1064 				hp->bzstream.bzfree = dumpbzfree;
1065 				(void) BZ2_bzCompressInit(&hp->bzstream,
1066 				    dump_bzip2_level, 0, 0);
1067 				hp->bzstream.opaque = NULL;
1068 			}
1069 		}
1070 	}
1071 
1072 	/* Finish allocating output buffers */
1073 	for (; cp < endcp && (sz + CBUF_SIZE) <= endsz; cp++) {
1074 		cp->state = CBUF_FREEBUF;
1075 		cp->size = CBUF_SIZE;
1076 		cp->buf = cfg->maxvm + sz;
1077 		sz += CBUF_SIZE;
1078 	}
1079 
1080 	/* Enable IS_DUMP_PAGE macro, which checks for pages we took. */
1081 	if (cfg->found4m || cfg->foundsm)
1082 		dump_check_used = 1;
1083 
1084 	ASSERT(sz <= endsz);
1085 }
1086 
1087 static void
1088 dumphdr_init(void)
1089 {
1090 	pgcnt_t npages = 0;
1091 
1092 	ASSERT(MUTEX_HELD(&dump_lock));
1093 
1094 	if (dumphdr == NULL) {
1095 		dumphdr = kmem_zalloc(sizeof (dumphdr_t), KM_SLEEP);
1096 		dumphdr->dump_magic = DUMP_MAGIC;
1097 		dumphdr->dump_version = DUMP_VERSION;
1098 		dumphdr->dump_wordsize = DUMP_WORDSIZE;
1099 		dumphdr->dump_pageshift = PAGESHIFT;
1100 		dumphdr->dump_pagesize = PAGESIZE;
1101 		dumphdr->dump_utsname = utsname;
1102 		(void) strcpy(dumphdr->dump_platform, platform);
1103 		dumpbuf.size = dumpbuf_iosize(maxphys);
1104 		dumpbuf.start = kmem_alloc(dumpbuf.size, KM_SLEEP);
1105 		dumpbuf.end = dumpbuf.start + dumpbuf.size;
1106 		dumpcfg.pids = kmem_alloc(v.v_proc * sizeof (pid_t), KM_SLEEP);
1107 		dumpcfg.helpermap = kmem_zalloc(BT_SIZEOFMAP(NCPU), KM_SLEEP);
1108 		LOCK_INIT_HELD(&dumpcfg.helper_lock);
1109 		dump_stack_scratch = kmem_alloc(STACK_BUF_SIZE, KM_SLEEP);
1110 		(void) strncpy(dumphdr->dump_uuid, dump_get_uuid(),
1111 		    sizeof (dumphdr->dump_uuid));
1112 	}
1113 
1114 	npages = num_phys_pages();
1115 
1116 	if (dumpcfg.bitmapsize != npages) {
1117 		size_t rlen = CBUF_MAPP2R(P2ROUNDUP(npages, CBUF_MAPNP));
1118 		void *map = kmem_alloc(BT_SIZEOFMAP(npages), KM_SLEEP);
1119 		void *rmap = kmem_alloc(BT_SIZEOFMAP(rlen), KM_SLEEP);
1120 
1121 		if (dumpcfg.bitmap != NULL)
1122 			kmem_free(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.
1123 			    bitmapsize));
1124 		if (dumpcfg.rbitmap != NULL)
1125 			kmem_free(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.
1126 			    rbitmapsize));
1127 		dumpcfg.bitmap = map;
1128 		dumpcfg.bitmapsize = npages;
1129 		dumpcfg.rbitmap = rmap;
1130 		dumpcfg.rbitmapsize = rlen;
1131 	}
1132 }
1133 
1134 /*
1135  * Establish a new dump device.
1136  */
1137 int
1138 dumpinit(vnode_t *vp, char *name, int justchecking)
1139 {
1140 	vnode_t *cvp;
1141 	vattr_t vattr;
1142 	vnode_t *cdev_vp;
1143 	int error = 0;
1144 
1145 	ASSERT(MUTEX_HELD(&dump_lock));
1146 
1147 	dumphdr_init();
1148 
1149 	cvp = common_specvp(vp);
1150 	if (cvp == dumpvp)
1151 		return (0);
1152 
1153 	/*
1154 	 * Determine whether this is a plausible dump device.  We want either:
1155 	 * (1) a real device that's not mounted and has a cb_dump routine, or
1156 	 * (2) a swapfile on some filesystem that has a vop_dump routine.
1157 	 */
1158 	if ((error = VOP_OPEN(&cvp, FREAD | FWRITE, kcred, NULL)) != 0)
1159 		return (error);
1160 
1161 	vattr.va_mask = AT_SIZE | AT_TYPE | AT_RDEV;
1162 	if ((error = VOP_GETATTR(cvp, &vattr, 0, kcred, NULL)) == 0) {
1163 		if (vattr.va_type == VBLK || vattr.va_type == VCHR) {
1164 			if (devopsp[getmajor(vattr.va_rdev)]->
1165 			    devo_cb_ops->cb_dump == nodev)
1166 				error = ENOTSUP;
1167 			else if (vfs_devismounted(vattr.va_rdev))
1168 				error = EBUSY;
1169 			if (strcmp(ddi_driver_name(VTOS(cvp)->s_dip),
1170 			    ZFS_DRIVER) == 0 &&
1171 			    IS_SWAPVP(common_specvp(cvp)))
1172 					error = EBUSY;
1173 		} else {
1174 			if (vn_matchopval(cvp, VOPNAME_DUMP, fs_nosys) ||
1175 			    !IS_SWAPVP(cvp))
1176 				error = ENOTSUP;
1177 		}
1178 	}
1179 
1180 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE)
1181 		error = ENOSPC;
1182 
1183 	if (error || justchecking) {
1184 		(void) VOP_CLOSE(cvp, FREAD | FWRITE, 1, (offset_t)0,
1185 		    kcred, NULL);
1186 		return (error);
1187 	}
1188 
1189 	VN_HOLD(cvp);
1190 
1191 	if (dumpvp != NULL)
1192 		dumpfini();	/* unconfigure the old dump device */
1193 
1194 	dumpvp = cvp;
1195 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
1196 	dumppath = kmem_alloc(strlen(name) + 1, KM_SLEEP);
1197 	(void) strcpy(dumppath, name);
1198 	dumpbuf.iosize = 0;
1199 
1200 	/*
1201 	 * If the dump device is a block device, attempt to open up the
1202 	 * corresponding character device and determine its maximum transfer
1203 	 * size.  We use this information to potentially resize dumpbuf to a
1204 	 * larger and more optimal size for performing i/o to the dump device.
1205 	 */
1206 	if (cvp->v_type == VBLK &&
1207 	    (cdev_vp = makespecvp(VTOS(cvp)->s_dev, VCHR)) != NULL) {
1208 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1209 			size_t blk_size;
1210 			struct dk_cinfo dki;
1211 			struct dk_minfo minf;
1212 
1213 			if (VOP_IOCTL(cdev_vp, DKIOCGMEDIAINFO,
1214 			    (intptr_t)&minf, FKIOCTL, kcred, NULL, NULL)
1215 			    == 0 && minf.dki_lbsize != 0)
1216 				blk_size = minf.dki_lbsize;
1217 			else
1218 				blk_size = DEV_BSIZE;
1219 
1220 			if (VOP_IOCTL(cdev_vp, DKIOCINFO, (intptr_t)&dki,
1221 			    FKIOCTL, kcred, NULL, NULL) == 0) {
1222 				dumpbuf.iosize = dki.dki_maxtransfer * blk_size;
1223 				dumpbuf_resize();
1224 			}
1225 			/*
1226 			 * If we are working with a zvol then dumpify it
1227 			 * if it's not being used as swap.
1228 			 */
1229 			if (strcmp(dki.dki_dname, ZVOL_DRIVER) == 0) {
1230 				if (IS_SWAPVP(common_specvp(cvp)))
1231 					error = EBUSY;
1232 				else if ((error = VOP_IOCTL(cdev_vp,
1233 				    DKIOCDUMPINIT, NULL, FKIOCTL, kcred,
1234 				    NULL, NULL)) != 0)
1235 					dumpfini();
1236 			}
1237 
1238 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1239 			    kcred, NULL);
1240 		}
1241 
1242 		VN_RELE(cdev_vp);
1243 	}
1244 
1245 	cmn_err(CE_CONT, "?dump on %s size %llu MB\n", name, dumpvp_size >> 20);
1246 
1247 	dump_update_clevel();
1248 
1249 	return (error);
1250 }
1251 
1252 void
1253 dumpfini(void)
1254 {
1255 	vattr_t vattr;
1256 	boolean_t is_zfs = B_FALSE;
1257 	vnode_t *cdev_vp;
1258 	ASSERT(MUTEX_HELD(&dump_lock));
1259 
1260 	kmem_free(dumppath, strlen(dumppath) + 1);
1261 
1262 	/*
1263 	 * Determine if we are using zvols for our dump device
1264 	 */
1265 	vattr.va_mask = AT_RDEV;
1266 	if (VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL) == 0) {
1267 		is_zfs = (getmajor(vattr.va_rdev) ==
1268 		    ddi_name_to_major(ZFS_DRIVER)) ? B_TRUE : B_FALSE;
1269 	}
1270 
1271 	/*
1272 	 * If we have a zvol dump device then we call into zfs so
1273 	 * that it may have a chance to cleanup.
1274 	 */
1275 	if (is_zfs &&
1276 	    (cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR)) != NULL) {
1277 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1278 			(void) VOP_IOCTL(cdev_vp, DKIOCDUMPFINI, NULL, FKIOCTL,
1279 			    kcred, NULL, NULL);
1280 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1281 			    kcred, NULL);
1282 		}
1283 		VN_RELE(cdev_vp);
1284 	}
1285 
1286 	(void) VOP_CLOSE(dumpvp, FREAD | FWRITE, 1, (offset_t)0, kcred, NULL);
1287 
1288 	VN_RELE(dumpvp);
1289 
1290 	dumpvp = NULL;
1291 	dumpvp_size = 0;
1292 	dumppath = NULL;
1293 }
1294 
1295 static offset_t
1296 dumpvp_flush(void)
1297 {
1298 	size_t size = P2ROUNDUP(dumpbuf.cur - dumpbuf.start, PAGESIZE);
1299 	hrtime_t iotime;
1300 	int err;
1301 
1302 	if (dumpbuf.vp_off + size > dumpbuf.vp_limit) {
1303 		dump_ioerr = ENOSPC;
1304 		dumpbuf.vp_off = dumpbuf.vp_limit;
1305 	} else if (size != 0) {
1306 		iotime = gethrtime();
1307 		dumpsync.iowait += iotime - dumpsync.iowaitts;
1308 		if (panicstr)
1309 			err = VOP_DUMP(dumpvp, dumpbuf.start,
1310 			    lbtodb(dumpbuf.vp_off), btod(size), NULL);
1311 		else
1312 			err = vn_rdwr(UIO_WRITE, dumpbuf.cdev_vp != NULL ?
1313 			    dumpbuf.cdev_vp : dumpvp, dumpbuf.start, size,
1314 			    dumpbuf.vp_off, UIO_SYSSPACE, 0, dumpbuf.vp_limit,
1315 			    kcred, 0);
1316 		if (err && dump_ioerr == 0)
1317 			dump_ioerr = err;
1318 		dumpsync.iowaitts = gethrtime();
1319 		dumpsync.iotime += dumpsync.iowaitts - iotime;
1320 		dumpsync.nwrite += size;
1321 		dumpbuf.vp_off += size;
1322 	}
1323 	dumpbuf.cur = dumpbuf.start;
1324 	dump_timeleft = dump_timeout;
1325 	return (dumpbuf.vp_off);
1326 }
1327 
1328 /* maximize write speed by keeping seek offset aligned with size */
1329 void
1330 dumpvp_write(const void *va, size_t size)
1331 {
1332 	size_t len, off, sz;
1333 
1334 	while (size != 0) {
1335 		len = MIN(size, dumpbuf.end - dumpbuf.cur);
1336 		if (len == 0) {
1337 			off = P2PHASE(dumpbuf.vp_off, dumpbuf.size);
1338 			if (off == 0 || !ISP2(dumpbuf.size)) {
1339 				(void) dumpvp_flush();
1340 			} else {
1341 				sz = dumpbuf.size - off;
1342 				dumpbuf.cur = dumpbuf.start + sz;
1343 				(void) dumpvp_flush();
1344 				ovbcopy(dumpbuf.start + sz, dumpbuf.start, off);
1345 				dumpbuf.cur += off;
1346 			}
1347 		} else {
1348 			bcopy(va, dumpbuf.cur, len);
1349 			va = (char *)va + len;
1350 			dumpbuf.cur += len;
1351 			size -= len;
1352 		}
1353 	}
1354 }
1355 
1356 /*ARGSUSED*/
1357 static void
1358 dumpvp_ksyms_write(const void *src, void *dst, size_t size)
1359 {
1360 	dumpvp_write(src, size);
1361 }
1362 
1363 /*
1364  * Mark 'pfn' in the bitmap and dump its translation table entry.
1365  */
1366 void
1367 dump_addpage(struct as *as, void *va, pfn_t pfn)
1368 {
1369 	mem_vtop_t mem_vtop;
1370 	pgcnt_t bitnum;
1371 
1372 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1373 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1374 			dumphdr->dump_npages++;
1375 			BT_SET(dumpcfg.bitmap, bitnum);
1376 		}
1377 		dumphdr->dump_nvtop++;
1378 		mem_vtop.m_as = as;
1379 		mem_vtop.m_va = va;
1380 		mem_vtop.m_pfn = pfn;
1381 		dumpvp_write(&mem_vtop, sizeof (mem_vtop_t));
1382 	}
1383 	dump_timeleft = dump_timeout;
1384 }
1385 
1386 /*
1387  * Mark 'pfn' in the bitmap
1388  */
1389 void
1390 dump_page(pfn_t pfn)
1391 {
1392 	pgcnt_t bitnum;
1393 
1394 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1395 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1396 			dumphdr->dump_npages++;
1397 			BT_SET(dumpcfg.bitmap, bitnum);
1398 		}
1399 	}
1400 	dump_timeleft = dump_timeout;
1401 }
1402 
1403 /*
1404  * Dump the <as, va, pfn> information for a given address space.
1405  * SEGOP_DUMP() will call dump_addpage() for each page in the segment.
1406  */
1407 static void
1408 dump_as(struct as *as)
1409 {
1410 	struct seg *seg;
1411 
1412 	AS_LOCK_ENTER(as, RW_READER);
1413 	for (seg = AS_SEGFIRST(as); seg; seg = AS_SEGNEXT(as, seg)) {
1414 		if (seg->s_as != as)
1415 			break;
1416 		if (seg->s_ops == NULL)
1417 			continue;
1418 		SEGOP_DUMP(seg);
1419 	}
1420 	AS_LOCK_EXIT(as);
1421 
1422 	if (seg != NULL)
1423 		cmn_err(CE_WARN, "invalid segment %p in address space %p",
1424 		    (void *)seg, (void *)as);
1425 }
1426 
1427 static int
1428 dump_process(pid_t pid)
1429 {
1430 	proc_t *p = sprlock(pid);
1431 
1432 	if (p == NULL)
1433 		return (-1);
1434 	if (p->p_as != &kas) {
1435 		mutex_exit(&p->p_lock);
1436 		dump_as(p->p_as);
1437 		mutex_enter(&p->p_lock);
1438 	}
1439 
1440 	sprunlock(p);
1441 
1442 	return (0);
1443 }
1444 
1445 /*
1446  * The following functions (dump_summary(), dump_ereports(), and
1447  * dump_messages()), write data to an uncompressed area within the
1448  * crashdump. The layout of these is
1449  *
1450  * +------------------------------------------------------------+
1451  * |     compressed pages       | summary | ereports | messages |
1452  * +------------------------------------------------------------+
1453  *
1454  * With the advent of saving a compressed crash dump by default, we
1455  * need to save a little more data to describe the failure mode in
1456  * an uncompressed buffer available before savecore uncompresses
1457  * the dump. Initially this is a copy of the stack trace. Additional
1458  * summary information should be added here.
1459  */
1460 
1461 void
1462 dump_summary(void)
1463 {
1464 	u_offset_t dumpvp_start;
1465 	summary_dump_t sd;
1466 
1467 	if (dumpvp == NULL || dumphdr == NULL)
1468 		return;
1469 
1470 	dumpbuf.cur = dumpbuf.start;
1471 
1472 	dumpbuf.vp_limit = dumpvp_size - (DUMP_OFFSET + DUMP_LOGSIZE +
1473 	    DUMP_ERPTSIZE);
1474 	dumpvp_start = dumpbuf.vp_limit - DUMP_SUMMARYSIZE;
1475 	dumpbuf.vp_off = dumpvp_start;
1476 
1477 	sd.sd_magic = SUMMARY_MAGIC;
1478 	sd.sd_ssum = checksum32(dump_stack_scratch, STACK_BUF_SIZE);
1479 	dumpvp_write(&sd, sizeof (sd));
1480 	dumpvp_write(dump_stack_scratch, STACK_BUF_SIZE);
1481 
1482 	sd.sd_magic = 0; /* indicate end of summary */
1483 	dumpvp_write(&sd, sizeof (sd));
1484 	(void) dumpvp_flush();
1485 }
1486 
1487 void
1488 dump_ereports(void)
1489 {
1490 	u_offset_t dumpvp_start;
1491 	erpt_dump_t ed;
1492 
1493 	if (dumpvp == NULL || dumphdr == NULL)
1494 		return;
1495 
1496 	dumpbuf.cur = dumpbuf.start;
1497 	dumpbuf.vp_limit = dumpvp_size - (DUMP_OFFSET + DUMP_LOGSIZE);
1498 	dumpvp_start = dumpbuf.vp_limit - DUMP_ERPTSIZE;
1499 	dumpbuf.vp_off = dumpvp_start;
1500 
1501 	fm_ereport_dump();
1502 	if (panicstr)
1503 		errorq_dump();
1504 
1505 	bzero(&ed, sizeof (ed)); /* indicate end of ereports */
1506 	dumpvp_write(&ed, sizeof (ed));
1507 	(void) dumpvp_flush();
1508 
1509 	if (!panicstr) {
1510 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1511 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1512 		    B_INVAL | B_FORCE, kcred, NULL);
1513 	}
1514 }
1515 
1516 void
1517 dump_messages(void)
1518 {
1519 	log_dump_t ld;
1520 	mblk_t *mctl, *mdata;
1521 	queue_t *q, *qlast;
1522 	u_offset_t dumpvp_start;
1523 
1524 	if (dumpvp == NULL || dumphdr == NULL || log_consq == NULL)
1525 		return;
1526 
1527 	dumpbuf.cur = dumpbuf.start;
1528 	dumpbuf.vp_limit = dumpvp_size - DUMP_OFFSET;
1529 	dumpvp_start = dumpbuf.vp_limit - DUMP_LOGSIZE;
1530 	dumpbuf.vp_off = dumpvp_start;
1531 
1532 	qlast = NULL;
1533 	do {
1534 		for (q = log_consq; q->q_next != qlast; q = q->q_next)
1535 			continue;
1536 		for (mctl = q->q_first; mctl != NULL; mctl = mctl->b_next) {
1537 			dump_timeleft = dump_timeout;
1538 			mdata = mctl->b_cont;
1539 			ld.ld_magic = LOG_MAGIC;
1540 			ld.ld_msgsize = MBLKL(mctl->b_cont);
1541 			ld.ld_csum = checksum32(mctl->b_rptr, MBLKL(mctl));
1542 			ld.ld_msum = checksum32(mdata->b_rptr, MBLKL(mdata));
1543 			dumpvp_write(&ld, sizeof (ld));
1544 			dumpvp_write(mctl->b_rptr, MBLKL(mctl));
1545 			dumpvp_write(mdata->b_rptr, MBLKL(mdata));
1546 		}
1547 	} while ((qlast = q) != log_consq);
1548 
1549 	ld.ld_magic = 0;		/* indicate end of messages */
1550 	dumpvp_write(&ld, sizeof (ld));
1551 	(void) dumpvp_flush();
1552 	if (!panicstr) {
1553 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1554 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1555 		    B_INVAL | B_FORCE, kcred, NULL);
1556 	}
1557 }
1558 
1559 /*
1560  * The following functions are called on multiple CPUs during dump.
1561  * They must not use most kernel services, because all cross-calls are
1562  * disabled during panic. Therefore, blocking locks and cache flushes
1563  * will not work.
1564  */
1565 
1566 /*
1567  * Copy pages, trapping ECC errors. Also, for robustness, trap data
1568  * access in case something goes wrong in the hat layer and the
1569  * mapping is broken.
1570  */
1571 static int
1572 dump_pagecopy(void *src, void *dst)
1573 {
1574 	long *wsrc = (long *)src;
1575 	long *wdst = (long *)dst;
1576 	const ulong_t ncopies = PAGESIZE / sizeof (long);
1577 	volatile int w = 0;
1578 	volatile int ueoff = -1;
1579 	on_trap_data_t otd;
1580 
1581 	if (on_trap(&otd, OT_DATA_EC | OT_DATA_ACCESS)) {
1582 		if (ueoff == -1)
1583 			ueoff = w * sizeof (long);
1584 		/* report "bad ECC" or "bad address" */
1585 #ifdef _LP64
1586 		if (otd.ot_trap & OT_DATA_EC)
1587 			wdst[w++] = 0x00badecc00badecc;
1588 		else
1589 			wdst[w++] = 0x00badadd00badadd;
1590 #else
1591 		if (otd.ot_trap & OT_DATA_EC)
1592 			wdst[w++] = 0x00badecc;
1593 		else
1594 			wdst[w++] = 0x00badadd;
1595 #endif
1596 	}
1597 	while (w < ncopies) {
1598 		wdst[w] = wsrc[w];
1599 		w++;
1600 	}
1601 	no_trap();
1602 	return (ueoff);
1603 }
1604 
1605 static void
1606 dumpsys_close_cq(cqueue_t *cq, int live)
1607 {
1608 	if (live) {
1609 		mutex_enter(&cq->mutex);
1610 		atomic_dec_uint(&cq->open);
1611 		cv_signal(&cq->cv);
1612 		mutex_exit(&cq->mutex);
1613 	} else {
1614 		atomic_dec_uint(&cq->open);
1615 	}
1616 }
1617 
1618 static inline void
1619 dumpsys_spinlock(lock_t *lp)
1620 {
1621 	uint_t backoff = 0;
1622 	int loop_count = 0;
1623 
1624 	while (LOCK_HELD(lp) || !lock_spin_try(lp)) {
1625 		if (++loop_count >= ncpus) {
1626 			backoff = mutex_lock_backoff(0);
1627 			loop_count = 0;
1628 		} else {
1629 			backoff = mutex_lock_backoff(backoff);
1630 		}
1631 		mutex_lock_delay(backoff);
1632 	}
1633 }
1634 
1635 static inline void
1636 dumpsys_spinunlock(lock_t *lp)
1637 {
1638 	lock_clear(lp);
1639 }
1640 
1641 static inline void
1642 dumpsys_lock(cqueue_t *cq, int live)
1643 {
1644 	if (live)
1645 		mutex_enter(&cq->mutex);
1646 	else
1647 		dumpsys_spinlock(&cq->spinlock);
1648 }
1649 
1650 static inline void
1651 dumpsys_unlock(cqueue_t *cq, int live, int signal)
1652 {
1653 	if (live) {
1654 		if (signal)
1655 			cv_signal(&cq->cv);
1656 		mutex_exit(&cq->mutex);
1657 	} else {
1658 		dumpsys_spinunlock(&cq->spinlock);
1659 	}
1660 }
1661 
1662 static void
1663 dumpsys_wait_cq(cqueue_t *cq, int live)
1664 {
1665 	if (live) {
1666 		cv_wait(&cq->cv, &cq->mutex);
1667 	} else {
1668 		dumpsys_spinunlock(&cq->spinlock);
1669 		while (cq->open)
1670 			if (cq->first)
1671 				break;
1672 		dumpsys_spinlock(&cq->spinlock);
1673 	}
1674 }
1675 
1676 static void
1677 dumpsys_put_cq(cqueue_t *cq, cbuf_t *cp, int newstate, int live)
1678 {
1679 	if (cp == NULL)
1680 		return;
1681 
1682 	dumpsys_lock(cq, live);
1683 
1684 	if (cq->ts != 0) {
1685 		cq->empty += gethrtime() - cq->ts;
1686 		cq->ts = 0;
1687 	}
1688 
1689 	cp->state = newstate;
1690 	cp->next = NULL;
1691 	if (cq->last == NULL)
1692 		cq->first = cp;
1693 	else
1694 		cq->last->next = cp;
1695 	cq->last = cp;
1696 
1697 	dumpsys_unlock(cq, live, 1);
1698 }
1699 
1700 static cbuf_t *
1701 dumpsys_get_cq(cqueue_t *cq, int live)
1702 {
1703 	cbuf_t *cp;
1704 	hrtime_t now = gethrtime();
1705 
1706 	dumpsys_lock(cq, live);
1707 
1708 	/* CONSTCOND */
1709 	while (1) {
1710 		cp = (cbuf_t *)cq->first;
1711 		if (cp == NULL) {
1712 			if (cq->open == 0)
1713 				break;
1714 			dumpsys_wait_cq(cq, live);
1715 			continue;
1716 		}
1717 		cq->first = cp->next;
1718 		if (cq->first == NULL) {
1719 			cq->last = NULL;
1720 			cq->ts = now;
1721 		}
1722 		break;
1723 	}
1724 
1725 	dumpsys_unlock(cq, live, cq->first != NULL || cq->open == 0);
1726 	return (cp);
1727 }
1728 
1729 /*
1730  * Send an error message to the console. If the main task is running
1731  * just write the message via uprintf. If a helper is running the
1732  * message has to be put on a queue for the main task. Setting fmt to
1733  * NULL means flush the error message buffer. If fmt is not NULL, just
1734  * add the text to the existing buffer.
1735  */
1736 static void
1737 dumpsys_errmsg(helper_t *hp, const char *fmt, ...)
1738 {
1739 	dumpsync_t *ds = hp->ds;
1740 	cbuf_t *cp = hp->cperr;
1741 	va_list adx;
1742 
1743 	if (hp->helper == MAINHELPER) {
1744 		if (fmt != NULL) {
1745 			if (ds->neednl) {
1746 				uprintf("\n");
1747 				ds->neednl = 0;
1748 			}
1749 			va_start(adx, fmt);
1750 			vuprintf(fmt, adx);
1751 			va_end(adx);
1752 		}
1753 	} else if (fmt == NULL) {
1754 		if (cp != NULL) {
1755 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1756 			hp->cperr = NULL;
1757 		}
1758 	} else {
1759 		if (hp->cperr == NULL) {
1760 			cp = CQ_GET(freebufq);
1761 			hp->cperr = cp;
1762 			cp->used = 0;
1763 		}
1764 		va_start(adx, fmt);
1765 		cp->used += vsnprintf(cp->buf + cp->used, cp->size - cp->used,
1766 		    fmt, adx);
1767 		va_end(adx);
1768 		if ((cp->used + LOG_MSGSIZE) > cp->size) {
1769 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1770 			hp->cperr = NULL;
1771 		}
1772 	}
1773 }
1774 
1775 /*
1776  * Write an output buffer to the dump file. If the main task is
1777  * running just write the data. If a helper is running the output is
1778  * placed on a queue for the main task.
1779  */
1780 static void
1781 dumpsys_swrite(helper_t *hp, cbuf_t *cp, size_t used)
1782 {
1783 	dumpsync_t *ds = hp->ds;
1784 
1785 	if (hp->helper == MAINHELPER) {
1786 		HRSTART(ds->perpage, write);
1787 		dumpvp_write(cp->buf, used);
1788 		HRSTOP(ds->perpage, write);
1789 		CQ_PUT(freebufq, cp, CBUF_FREEBUF);
1790 	} else {
1791 		cp->used = used;
1792 		CQ_PUT(mainq, cp, CBUF_WRITE);
1793 	}
1794 }
1795 
1796 /*
1797  * Copy one page within the mapped range. The offset starts at 0 and
1798  * is relative to the first pfn. cp->buf + cp->off is the address of
1799  * the first pfn. If dump_pagecopy returns a UE offset, create an
1800  * error message.  Returns the offset to the next pfn in the range
1801  * selected by the bitmap.
1802  */
1803 static int
1804 dumpsys_copy_page(helper_t *hp, int offset)
1805 {
1806 	cbuf_t *cp = hp->cpin;
1807 	int ueoff;
1808 
1809 	ASSERT(cp->off + offset + PAGESIZE <= cp->size);
1810 	ASSERT(BT_TEST(dumpcfg.bitmap, cp->bitnum));
1811 
1812 	ueoff = dump_pagecopy(cp->buf + cp->off + offset, hp->page);
1813 
1814 	/* ueoff is the offset in the page to a UE error */
1815 	if (ueoff != -1) {
1816 		uint64_t pa = ptob(cp->pfn) + offset + ueoff;
1817 
1818 		dumpsys_errmsg(hp, "cpu %d: memory error at PA 0x%08x.%08x\n",
1819 		    CPU->cpu_id, (uint32_t)(pa >> 32), (uint32_t)pa);
1820 	}
1821 
1822 	/*
1823 	 * Advance bitnum and offset to the next input page for the
1824 	 * next call to this function.
1825 	 */
1826 	offset += PAGESIZE;
1827 	cp->bitnum++;
1828 	while (cp->off + offset < cp->size) {
1829 		if (BT_TEST(dumpcfg.bitmap, cp->bitnum))
1830 			break;
1831 		offset += PAGESIZE;
1832 		cp->bitnum++;
1833 	}
1834 
1835 	return (offset);
1836 }
1837 
1838 /*
1839  * Read the helper queue, and copy one mapped page. Return 0 when
1840  * done. Return 1 when a page has been copied into hp->page.
1841  */
1842 static int
1843 dumpsys_sread(helper_t *hp)
1844 {
1845 	dumpsync_t *ds = hp->ds;
1846 
1847 	/* CONSTCOND */
1848 	while (1) {
1849 
1850 		/* Find the next input buffer. */
1851 		if (hp->cpin == NULL) {
1852 			HRSTART(hp->perpage, inwait);
1853 
1854 			/* CONSTCOND */
1855 			while (1) {
1856 				hp->cpin = CQ_GET(helperq);
1857 				dump_timeleft = dump_timeout;
1858 
1859 				/*
1860 				 * NULL return means the helper queue
1861 				 * is closed and empty.
1862 				 */
1863 				if (hp->cpin == NULL)
1864 					break;
1865 
1866 				/* Have input, check for dump I/O error. */
1867 				if (!dump_ioerr)
1868 					break;
1869 
1870 				/*
1871 				 * If an I/O error occurs, stay in the
1872 				 * loop in order to empty the helper
1873 				 * queue. Return the buffers to the
1874 				 * main task to unmap and free it.
1875 				 */
1876 				hp->cpin->used = 0;
1877 				CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1878 			}
1879 			HRSTOP(hp->perpage, inwait);
1880 
1881 			/* Stop here when the helper queue is closed. */
1882 			if (hp->cpin == NULL)
1883 				break;
1884 
1885 			/* Set the offset=0 to get the first pfn. */
1886 			hp->in = 0;
1887 
1888 			/* Set the total processed to 0 */
1889 			hp->used = 0;
1890 		}
1891 
1892 		/* Process the next page. */
1893 		if (hp->used < hp->cpin->used) {
1894 
1895 			/*
1896 			 * Get the next page from the input buffer and
1897 			 * return a copy.
1898 			 */
1899 			ASSERT(hp->in != -1);
1900 			HRSTART(hp->perpage, copy);
1901 			hp->in = dumpsys_copy_page(hp, hp->in);
1902 			hp->used += PAGESIZE;
1903 			HRSTOP(hp->perpage, copy);
1904 			break;
1905 
1906 		} else {
1907 
1908 			/*
1909 			 * Done with the input. Flush the VM and
1910 			 * return the buffer to the main task.
1911 			 */
1912 			if (panicstr && hp->helper != MAINHELPER)
1913 				hat_flush_range(kas.a_hat,
1914 				    hp->cpin->buf, hp->cpin->size);
1915 			dumpsys_errmsg(hp, NULL);
1916 			CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1917 			hp->cpin = NULL;
1918 		}
1919 	}
1920 
1921 	return (hp->cpin != NULL);
1922 }
1923 
1924 /*
1925  * Compress size bytes starting at buf with bzip2
1926  * mode:
1927  *	BZ_RUN		add one more compressed page
1928  *	BZ_FINISH	no more input, flush the state
1929  */
1930 static void
1931 dumpsys_bzrun(helper_t *hp, void *buf, size_t size, int mode)
1932 {
1933 	dumpsync_t *ds = hp->ds;
1934 	const int CSIZE = sizeof (dumpcsize_t);
1935 	bz_stream *ps = &hp->bzstream;
1936 	int rc = 0;
1937 	uint32_t csize;
1938 	dumpcsize_t cs;
1939 
1940 	/* Set input pointers to new input page */
1941 	if (size > 0) {
1942 		ps->avail_in = size;
1943 		ps->next_in = buf;
1944 	}
1945 
1946 	/* CONSTCOND */
1947 	while (1) {
1948 
1949 		/* Quit when all input has been consumed */
1950 		if (ps->avail_in == 0 && mode == BZ_RUN)
1951 			break;
1952 
1953 		/* Get a new output buffer */
1954 		if (hp->cpout == NULL) {
1955 			HRSTART(hp->perpage, outwait);
1956 			hp->cpout = CQ_GET(freebufq);
1957 			HRSTOP(hp->perpage, outwait);
1958 			ps->avail_out = hp->cpout->size - CSIZE;
1959 			ps->next_out = hp->cpout->buf + CSIZE;
1960 		}
1961 
1962 		/* Compress input, or finalize */
1963 		HRSTART(hp->perpage, compress);
1964 		rc = BZ2_bzCompress(ps, mode);
1965 		HRSTOP(hp->perpage, compress);
1966 
1967 		/* Check for error */
1968 		if (mode == BZ_RUN && rc != BZ_RUN_OK) {
1969 			dumpsys_errmsg(hp, "%d: BZ_RUN error %s at page %lx\n",
1970 			    hp->helper, BZ2_bzErrorString(rc),
1971 			    hp->cpin->pagenum);
1972 			break;
1973 		}
1974 
1975 		/* Write the buffer if it is full, or we are flushing */
1976 		if (ps->avail_out == 0 || mode == BZ_FINISH) {
1977 			csize = hp->cpout->size - CSIZE - ps->avail_out;
1978 			cs = DUMP_SET_TAG(csize, hp->tag);
1979 			if (csize > 0) {
1980 				(void) memcpy(hp->cpout->buf, &cs, CSIZE);
1981 				dumpsys_swrite(hp, hp->cpout, csize + CSIZE);
1982 				hp->cpout = NULL;
1983 			}
1984 		}
1985 
1986 		/* Check for final complete */
1987 		if (mode == BZ_FINISH) {
1988 			if (rc == BZ_STREAM_END)
1989 				break;
1990 			if (rc != BZ_FINISH_OK) {
1991 				dumpsys_errmsg(hp, "%d: BZ_FINISH error %s\n",
1992 				    hp->helper, BZ2_bzErrorString(rc));
1993 				break;
1994 			}
1995 		}
1996 	}
1997 
1998 	/* Cleanup state and buffers */
1999 	if (mode == BZ_FINISH) {
2000 
2001 		/* Reset state so that it is re-usable. */
2002 		(void) BZ2_bzCompressReset(&hp->bzstream);
2003 
2004 		/* Give any unused outout buffer to the main task */
2005 		if (hp->cpout != NULL) {
2006 			hp->cpout->used = 0;
2007 			CQ_PUT(mainq, hp->cpout, CBUF_ERRMSG);
2008 			hp->cpout = NULL;
2009 		}
2010 	}
2011 }
2012 
2013 static void
2014 dumpsys_bz2compress(helper_t *hp)
2015 {
2016 	dumpsync_t *ds = hp->ds;
2017 	dumpstreamhdr_t sh;
2018 
2019 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
2020 	sh.stream_pagenum = (pgcnt_t)-1;
2021 	sh.stream_npages = 0;
2022 	hp->cpin = NULL;
2023 	hp->cpout = NULL;
2024 	hp->cperr = NULL;
2025 	hp->in = 0;
2026 	hp->out = 0;
2027 	hp->bzstream.avail_in = 0;
2028 
2029 	/* Bump reference to mainq while we are running */
2030 	CQ_OPEN(mainq);
2031 
2032 	/* Get one page at a time */
2033 	while (dumpsys_sread(hp)) {
2034 		if (sh.stream_pagenum != hp->cpin->pagenum) {
2035 			sh.stream_pagenum = hp->cpin->pagenum;
2036 			sh.stream_npages = btop(hp->cpin->used);
2037 			dumpsys_bzrun(hp, &sh, sizeof (sh), BZ_RUN);
2038 		}
2039 		dumpsys_bzrun(hp, hp->page, PAGESIZE, 0);
2040 	}
2041 
2042 	/* Done with input, flush any partial buffer */
2043 	if (sh.stream_pagenum != (pgcnt_t)-1) {
2044 		dumpsys_bzrun(hp, NULL, 0, BZ_FINISH);
2045 		dumpsys_errmsg(hp, NULL);
2046 	}
2047 
2048 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
2049 
2050 	/* Decrement main queue count, we are done */
2051 	CQ_CLOSE(mainq);
2052 }
2053 
2054 /*
2055  * Compress with lzjb
2056  * write stream block if full or size==0
2057  * if csize==0 write stream header, else write <csize, data>
2058  * size==0 is a call to flush a buffer
2059  * hp->cpout is the buffer we are flushing or filling
2060  * hp->out is the next index to fill data
2061  * osize is either csize+data, or the size of a stream header
2062  */
2063 static void
2064 dumpsys_lzjbrun(helper_t *hp, size_t csize, void *buf, size_t size)
2065 {
2066 	dumpsync_t *ds = hp->ds;
2067 	const int CSIZE = sizeof (dumpcsize_t);
2068 	dumpcsize_t cs;
2069 	size_t osize = csize > 0 ? CSIZE + size : size;
2070 
2071 	/* If flush, and there is no buffer, just return */
2072 	if (size == 0 && hp->cpout == NULL)
2073 		return;
2074 
2075 	/* If flush, or cpout is full, write it out */
2076 	if (size == 0 ||
2077 	    hp->cpout != NULL && hp->out + osize > hp->cpout->size) {
2078 
2079 		/* Set tag+size word at the front of the stream block. */
2080 		cs = DUMP_SET_TAG(hp->out - CSIZE, hp->tag);
2081 		(void) memcpy(hp->cpout->buf, &cs, CSIZE);
2082 
2083 		/* Write block to dump file. */
2084 		dumpsys_swrite(hp, hp->cpout, hp->out);
2085 
2086 		/* Clear pointer to indicate we need a new buffer */
2087 		hp->cpout = NULL;
2088 
2089 		/* flushing, we are done */
2090 		if (size == 0)
2091 			return;
2092 	}
2093 
2094 	/* Get an output buffer if we dont have one. */
2095 	if (hp->cpout == NULL) {
2096 		HRSTART(hp->perpage, outwait);
2097 		hp->cpout = CQ_GET(freebufq);
2098 		HRSTOP(hp->perpage, outwait);
2099 		hp->out = CSIZE;
2100 	}
2101 
2102 	/* Store csize word. This is the size of compressed data. */
2103 	if (csize > 0) {
2104 		cs = DUMP_SET_TAG(csize, 0);
2105 		(void) memcpy(hp->cpout->buf + hp->out, &cs, CSIZE);
2106 		hp->out += CSIZE;
2107 	}
2108 
2109 	/* Store the data. */
2110 	(void) memcpy(hp->cpout->buf + hp->out, buf, size);
2111 	hp->out += size;
2112 }
2113 
2114 static void
2115 dumpsys_lzjbcompress(helper_t *hp)
2116 {
2117 	dumpsync_t *ds = hp->ds;
2118 	size_t csize;
2119 	dumpstreamhdr_t sh;
2120 
2121 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
2122 	sh.stream_pagenum = (pfn_t)-1;
2123 	sh.stream_npages = 0;
2124 	hp->cpin = NULL;
2125 	hp->cpout = NULL;
2126 	hp->cperr = NULL;
2127 	hp->in = 0;
2128 	hp->out = 0;
2129 
2130 	/* Bump reference to mainq while we are running */
2131 	CQ_OPEN(mainq);
2132 
2133 	/* Get one page at a time */
2134 	while (dumpsys_sread(hp)) {
2135 
2136 		/* Create a stream header for each new input map */
2137 		if (sh.stream_pagenum != hp->cpin->pagenum) {
2138 			sh.stream_pagenum = hp->cpin->pagenum;
2139 			sh.stream_npages = btop(hp->cpin->used);
2140 			dumpsys_lzjbrun(hp, 0, &sh, sizeof (sh));
2141 		}
2142 
2143 		/* Compress one page */
2144 		HRSTART(hp->perpage, compress);
2145 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2146 		HRSTOP(hp->perpage, compress);
2147 
2148 		/* Add csize+data to output block */
2149 		ASSERT(csize > 0 && csize <= PAGESIZE);
2150 		dumpsys_lzjbrun(hp, csize, hp->lzbuf, csize);
2151 	}
2152 
2153 	/* Done with input, flush any partial buffer */
2154 	if (sh.stream_pagenum != (pfn_t)-1) {
2155 		dumpsys_lzjbrun(hp, 0, NULL, 0);
2156 		dumpsys_errmsg(hp, NULL);
2157 	}
2158 
2159 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
2160 
2161 	/* Decrement main queue count, we are done */
2162 	CQ_CLOSE(mainq);
2163 }
2164 
2165 /*
2166  * Dump helper called from panic_idle() to compress pages.  CPUs in
2167  * this path must not call most kernel services.
2168  *
2169  * During panic, all but one of the CPUs is idle. These CPUs are used
2170  * as helpers working in parallel to copy and compress memory
2171  * pages. During a panic, however, these processors cannot call any
2172  * kernel services. This is because mutexes become no-ops during
2173  * panic, and, cross-call interrupts are inhibited.  Therefore, during
2174  * panic dump the helper CPUs communicate with the panic CPU using
2175  * memory variables. All memory mapping and I/O is performed by the
2176  * panic CPU.
2177  *
2178  * At dump configuration time, helper_lock is set and helpers_wanted
2179  * is 0. dumpsys() decides whether to set helpers_wanted before
2180  * clearing helper_lock.
2181  *
2182  * At panic time, idle CPUs spin-wait on helper_lock, then alternately
2183  * take the lock and become a helper, or return.
2184  */
2185 void
2186 dumpsys_helper()
2187 {
2188 	dumpsys_spinlock(&dumpcfg.helper_lock);
2189 	if (dumpcfg.helpers_wanted) {
2190 		helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2191 
2192 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2193 			if (hp->helper == FREEHELPER) {
2194 				hp->helper = CPU->cpu_id;
2195 				BT_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2196 
2197 				dumpsys_spinunlock(&dumpcfg.helper_lock);
2198 
2199 				if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2200 					dumpsys_lzjbcompress(hp);
2201 				else
2202 					dumpsys_bz2compress(hp);
2203 
2204 				hp->helper = DONEHELPER;
2205 				return;
2206 			}
2207 		}
2208 
2209 		/* No more helpers are needed. */
2210 		dumpcfg.helpers_wanted = 0;
2211 
2212 	}
2213 	dumpsys_spinunlock(&dumpcfg.helper_lock);
2214 }
2215 
2216 /*
2217  * No-wait helper callable in spin loops.
2218  *
2219  * Do not wait for helper_lock. Just check helpers_wanted. The caller
2220  * may decide to continue. This is the "c)ontinue, s)ync, r)eset? s"
2221  * case.
2222  */
2223 void
2224 dumpsys_helper_nw()
2225 {
2226 	if (dumpcfg.helpers_wanted)
2227 		dumpsys_helper();
2228 }
2229 
2230 /*
2231  * Dump helper for live dumps.
2232  * These run as a system task.
2233  */
2234 static void
2235 dumpsys_live_helper(void *arg)
2236 {
2237 	helper_t *hp = arg;
2238 
2239 	BT_ATOMIC_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2240 	if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2241 		dumpsys_lzjbcompress(hp);
2242 	else
2243 		dumpsys_bz2compress(hp);
2244 }
2245 
2246 /*
2247  * Compress one page with lzjb (single threaded case)
2248  */
2249 static void
2250 dumpsys_lzjb_page(helper_t *hp, cbuf_t *cp)
2251 {
2252 	dumpsync_t *ds = hp->ds;
2253 	uint32_t csize;
2254 
2255 	hp->helper = MAINHELPER;
2256 	hp->in = 0;
2257 	hp->used = 0;
2258 	hp->cpin = cp;
2259 	while (hp->used < cp->used) {
2260 		HRSTART(hp->perpage, copy);
2261 		hp->in = dumpsys_copy_page(hp, hp->in);
2262 		hp->used += PAGESIZE;
2263 		HRSTOP(hp->perpage, copy);
2264 
2265 		HRSTART(hp->perpage, compress);
2266 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2267 		HRSTOP(hp->perpage, compress);
2268 
2269 		HRSTART(hp->perpage, write);
2270 		dumpvp_write(&csize, sizeof (csize));
2271 		dumpvp_write(hp->lzbuf, csize);
2272 		HRSTOP(hp->perpage, write);
2273 	}
2274 	CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
2275 	hp->cpin = NULL;
2276 }
2277 
2278 /*
2279  * Main task to dump pages. This is called on the dump CPU.
2280  */
2281 static void
2282 dumpsys_main_task(void *arg)
2283 {
2284 	dumpsync_t *ds = arg;
2285 	pgcnt_t pagenum = 0, bitnum = 0, hibitnum;
2286 	dumpmlw_t mlw;
2287 	cbuf_t *cp;
2288 	pgcnt_t baseoff, pfnoff;
2289 	pfn_t base, pfn;
2290 	int i, dumpserial;
2291 
2292 	/*
2293 	 * Fall back to serial mode if there are no helpers.
2294 	 * dump_plat_mincpu can be set to 0 at any time.
2295 	 * dumpcfg.helpermap must contain at least one member.
2296 	 */
2297 	dumpserial = 1;
2298 
2299 	if (dump_plat_mincpu != 0 && dumpcfg.clevel != 0) {
2300 		for (i = 0; i < BT_BITOUL(NCPU); ++i) {
2301 			if (dumpcfg.helpermap[i] != 0) {
2302 				dumpserial = 0;
2303 				break;
2304 			}
2305 		}
2306 	}
2307 
2308 	if (dumpserial) {
2309 		dumpcfg.clevel = 0;
2310 		if (dumpcfg.helper[0].lzbuf == NULL)
2311 			dumpcfg.helper[0].lzbuf = dumpcfg.helper[1].page;
2312 	}
2313 
2314 	dump_init_memlist_walker(&mlw);
2315 
2316 	for (;;) {
2317 		int sec = (gethrtime() - ds->start) / NANOSEC;
2318 
2319 		/*
2320 		 * Render a simple progress display on the system console to
2321 		 * make clear to the operator that the system has not hung.
2322 		 * Emit an update when dump progress has advanced by one
2323 		 * percent, or when no update has been drawn in the last
2324 		 * second.
2325 		 */
2326 		if (ds->percent > ds->percent_done || sec > ds->sec_done) {
2327 			ds->sec_done = sec;
2328 			ds->percent_done = ds->percent;
2329 			uprintf("^\rdumping: %2d:%02d %3d%% done",
2330 			    sec / 60, sec % 60, ds->percent);
2331 			ds->neednl = 1;
2332 		}
2333 
2334 		while (CQ_IS_EMPTY(mainq) && !CQ_IS_EMPTY(writerq)) {
2335 
2336 			/* the writerq never blocks */
2337 			cp = CQ_GET(writerq);
2338 			if (cp == NULL)
2339 				break;
2340 
2341 			dump_timeleft = dump_timeout;
2342 
2343 			HRSTART(ds->perpage, write);
2344 			dumpvp_write(cp->buf, cp->used);
2345 			HRSTOP(ds->perpage, write);
2346 
2347 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2348 		}
2349 
2350 		/*
2351 		 * Wait here for some buffers to process. Returns NULL
2352 		 * when all helpers have terminated and all buffers
2353 		 * have been processed.
2354 		 */
2355 		cp = CQ_GET(mainq);
2356 
2357 		if (cp == NULL) {
2358 
2359 			/* Drain the write queue. */
2360 			if (!CQ_IS_EMPTY(writerq))
2361 				continue;
2362 
2363 			/* Main task exits here. */
2364 			break;
2365 		}
2366 
2367 		dump_timeleft = dump_timeout;
2368 
2369 		switch (cp->state) {
2370 
2371 		case CBUF_FREEMAP:
2372 
2373 			/*
2374 			 * Note that we drop CBUF_FREEMAP buffers on
2375 			 * the floor (they will not be on any cqueue)
2376 			 * when we no longer need them.
2377 			 */
2378 			if (bitnum >= dumpcfg.bitmapsize)
2379 				break;
2380 
2381 			if (dump_ioerr) {
2382 				bitnum = dumpcfg.bitmapsize;
2383 				CQ_CLOSE(helperq);
2384 				break;
2385 			}
2386 
2387 			HRSTART(ds->perpage, bitmap);
2388 			for (; bitnum < dumpcfg.bitmapsize; bitnum++)
2389 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2390 					break;
2391 			HRSTOP(ds->perpage, bitmap);
2392 			dump_timeleft = dump_timeout;
2393 
2394 			if (bitnum >= dumpcfg.bitmapsize) {
2395 				CQ_CLOSE(helperq);
2396 				break;
2397 			}
2398 
2399 			/*
2400 			 * Try to map CBUF_MAPSIZE ranges. Can't
2401 			 * assume that memory segment size is a
2402 			 * multiple of CBUF_MAPSIZE. Can't assume that
2403 			 * the segment starts on a CBUF_MAPSIZE
2404 			 * boundary.
2405 			 */
2406 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2407 			ASSERT(pfn != PFN_INVALID);
2408 			ASSERT(bitnum + mlw.mpleft <= dumpcfg.bitmapsize);
2409 
2410 			base = P2ALIGN(pfn, CBUF_MAPNP);
2411 			if (base < mlw.mpaddr) {
2412 				base = mlw.mpaddr;
2413 				baseoff = P2PHASE(base, CBUF_MAPNP);
2414 			} else {
2415 				baseoff = 0;
2416 			}
2417 
2418 			pfnoff = pfn - base;
2419 			if (pfnoff + mlw.mpleft < CBUF_MAPNP) {
2420 				hibitnum = bitnum + mlw.mpleft;
2421 				cp->size = ptob(pfnoff + mlw.mpleft);
2422 			} else {
2423 				hibitnum = bitnum - pfnoff + CBUF_MAPNP -
2424 				    baseoff;
2425 				cp->size = CBUF_MAPSIZE - ptob(baseoff);
2426 			}
2427 
2428 			cp->pfn = pfn;
2429 			cp->bitnum = bitnum++;
2430 			cp->pagenum = pagenum++;
2431 			cp->off = ptob(pfnoff);
2432 
2433 			for (; bitnum < hibitnum; bitnum++)
2434 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2435 					pagenum++;
2436 
2437 			dump_timeleft = dump_timeout;
2438 			cp->used = ptob(pagenum - cp->pagenum);
2439 
2440 			HRSTART(ds->perpage, map);
2441 			hat_devload(kas.a_hat, cp->buf, cp->size, base,
2442 			    PROT_READ, HAT_LOAD_NOCONSIST);
2443 			HRSTOP(ds->perpage, map);
2444 
2445 			ds->pages_mapped += btop(cp->size);
2446 			ds->pages_used += pagenum - cp->pagenum;
2447 
2448 			CQ_OPEN(mainq);
2449 
2450 			/*
2451 			 * If there are no helpers the main task does
2452 			 * non-streams lzjb compress.
2453 			 */
2454 			if (dumpserial) {
2455 				dumpsys_lzjb_page(dumpcfg.helper, cp);
2456 				break;
2457 			}
2458 
2459 			/* pass mapped pages to a helper */
2460 			CQ_PUT(helperq, cp, CBUF_INREADY);
2461 
2462 			/* the last page was done */
2463 			if (bitnum >= dumpcfg.bitmapsize)
2464 				CQ_CLOSE(helperq);
2465 
2466 			break;
2467 
2468 		case CBUF_USEDMAP:
2469 
2470 			ds->npages += btop(cp->used);
2471 
2472 			HRSTART(ds->perpage, unmap);
2473 			hat_unload(kas.a_hat, cp->buf, cp->size, HAT_UNLOAD);
2474 			HRSTOP(ds->perpage, unmap);
2475 
2476 			if (bitnum < dumpcfg.bitmapsize)
2477 				CQ_PUT(mainq, cp, CBUF_FREEMAP);
2478 			CQ_CLOSE(mainq);
2479 
2480 			ASSERT(ds->npages <= dumphdr->dump_npages);
2481 			ds->percent = ds->npages * 100LL / dumphdr->dump_npages;
2482 			break;
2483 
2484 		case CBUF_WRITE:
2485 
2486 			CQ_PUT(writerq, cp, CBUF_WRITE);
2487 			break;
2488 
2489 		case CBUF_ERRMSG:
2490 
2491 			if (cp->used > 0) {
2492 				cp->buf[cp->size - 2] = '\n';
2493 				cp->buf[cp->size - 1] = '\0';
2494 				if (ds->neednl) {
2495 					uprintf("\n%s", cp->buf);
2496 					ds->neednl = 0;
2497 				} else {
2498 					uprintf("%s", cp->buf);
2499 				}
2500 				/* wait for console output */
2501 				drv_usecwait(200000);
2502 				dump_timeleft = dump_timeout;
2503 			}
2504 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2505 			break;
2506 
2507 		default:
2508 			uprintf("dump: unexpected buffer state %d, "
2509 			    "buffer will be lost\n", cp->state);
2510 			break;
2511 
2512 		} /* end switch */
2513 	}
2514 }
2515 
2516 #ifdef	COLLECT_METRICS
2517 size_t
2518 dumpsys_metrics(dumpsync_t *ds, char *buf, size_t size)
2519 {
2520 	dumpcfg_t *cfg = &dumpcfg;
2521 	int myid = CPU->cpu_seqid;
2522 	int i, compress_ratio;
2523 	int sec, iorate;
2524 	helper_t *hp, *hpend = &cfg->helper[cfg->nhelper];
2525 	char *e = buf + size;
2526 	char *p = buf;
2527 
2528 	sec = ds->elapsed / (1000 * 1000 * 1000ULL);
2529 	if (sec < 1)
2530 		sec = 1;
2531 
2532 	if (ds->iotime < 1)
2533 		ds->iotime = 1;
2534 	iorate = (ds->nwrite * 100000ULL) / ds->iotime;
2535 
2536 	compress_ratio = 100LL * ds->npages / btopr(ds->nwrite + 1);
2537 
2538 #define	P(...) (p += p < e ? snprintf(p, e - p, __VA_ARGS__) : 0)
2539 
2540 	P("Master cpu_seqid,%d\n", CPU->cpu_seqid);
2541 	P("Master cpu_id,%d\n", CPU->cpu_id);
2542 	P("dump_flags,0x%x\n", dumphdr->dump_flags);
2543 	P("dump_ioerr,%d\n", dump_ioerr);
2544 
2545 	P("Helpers:\n");
2546 	for (i = 0; i < ncpus; i++) {
2547 		if ((i & 15) == 0)
2548 			P(",,%03d,", i);
2549 		if (i == myid)
2550 			P("   M");
2551 		else if (BT_TEST(cfg->helpermap, i))
2552 			P("%4d", cpu_seq[i]->cpu_id);
2553 		else
2554 			P("   *");
2555 		if ((i & 15) == 15)
2556 			P("\n");
2557 	}
2558 
2559 	P("ncbuf_used,%d\n", cfg->ncbuf_used);
2560 	P("ncmap,%d\n", cfg->ncmap);
2561 
2562 	P("Found %ldM ranges,%ld\n", (CBUF_MAPSIZE / DUMP_1MB), cfg->found4m);
2563 	P("Found small pages,%ld\n", cfg->foundsm);
2564 
2565 	P("Compression level,%d\n", cfg->clevel);
2566 	P("Compression type,%s %s\n", cfg->clevel == 0 ? "serial" : "parallel",
2567 	    cfg->clevel >= DUMP_CLEVEL_BZIP2 ? "bzip2" : "lzjb");
2568 	P("Compression ratio,%d.%02d\n", compress_ratio / 100, compress_ratio %
2569 	    100);
2570 	P("nhelper_used,%d\n", cfg->nhelper_used);
2571 
2572 	P("Dump I/O rate MBS,%d.%02d\n", iorate / 100, iorate % 100);
2573 	P("..total bytes,%lld\n", (u_longlong_t)ds->nwrite);
2574 	P("..total nsec,%lld\n", (u_longlong_t)ds->iotime);
2575 	P("dumpbuf.iosize,%ld\n", dumpbuf.iosize);
2576 	P("dumpbuf.size,%ld\n", dumpbuf.size);
2577 
2578 	P("Dump pages/sec,%llu\n", (u_longlong_t)ds->npages / sec);
2579 	P("Dump pages,%llu\n", (u_longlong_t)ds->npages);
2580 	P("Dump time,%d\n", sec);
2581 
2582 	if (ds->pages_mapped > 0)
2583 		P("per-cent map utilization,%d\n", (int)((100 * ds->pages_used)
2584 		    / ds->pages_mapped));
2585 
2586 	P("\nPer-page metrics:\n");
2587 	if (ds->npages > 0) {
2588 		for (hp = cfg->helper; hp != hpend; hp++) {
2589 #define	PERPAGE(x)	ds->perpage.x += hp->perpage.x;
2590 			PERPAGES;
2591 #undef PERPAGE
2592 		}
2593 #define	PERPAGE(x) \
2594 		P("%s nsec/page,%d\n", #x, (int)(ds->perpage.x / ds->npages));
2595 		PERPAGES;
2596 #undef PERPAGE
2597 		P("freebufq.empty,%d\n", (int)(ds->freebufq.empty /
2598 		    ds->npages));
2599 		P("helperq.empty,%d\n", (int)(ds->helperq.empty /
2600 		    ds->npages));
2601 		P("writerq.empty,%d\n", (int)(ds->writerq.empty /
2602 		    ds->npages));
2603 		P("mainq.empty,%d\n", (int)(ds->mainq.empty / ds->npages));
2604 
2605 		P("I/O wait nsec/page,%llu\n", (u_longlong_t)(ds->iowait /
2606 		    ds->npages));
2607 	}
2608 #undef P
2609 	if (p < e)
2610 		bzero(p, e - p);
2611 	return (p - buf);
2612 }
2613 #endif	/* COLLECT_METRICS */
2614 
2615 /*
2616  * Dump the system.
2617  */
2618 void
2619 dumpsys(void)
2620 {
2621 	dumpsync_t *ds = &dumpsync;
2622 	taskq_t *livetaskq = NULL;
2623 	pfn_t pfn;
2624 	pgcnt_t bitnum;
2625 	proc_t *p;
2626 	helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2627 	cbuf_t *cp;
2628 	pid_t npids, pidx;
2629 	char *content;
2630 	char *buf;
2631 	size_t size;
2632 	int save_dump_clevel;
2633 	dumpmlw_t mlw;
2634 	dumpcsize_t datatag;
2635 	dumpdatahdr_t datahdr;
2636 
2637 	if (dumpvp == NULL || dumphdr == NULL) {
2638 		uprintf("skipping system dump - no dump device configured\n");
2639 		if (panicstr) {
2640 			dumpcfg.helpers_wanted = 0;
2641 			dumpsys_spinunlock(&dumpcfg.helper_lock);
2642 		}
2643 		return;
2644 	}
2645 	dumpbuf.cur = dumpbuf.start;
2646 
2647 	/* clear the sync variables */
2648 	ASSERT(dumpcfg.nhelper > 0);
2649 	bzero(ds, sizeof (*ds));
2650 	ds->dumpcpu = CPU->cpu_id;
2651 
2652 	/*
2653 	 * Calculate the starting block for dump.  If we're dumping on a
2654 	 * swap device, start 1/5 of the way in; otherwise, start at the
2655 	 * beginning.  And never use the first page -- it may be a disk label.
2656 	 */
2657 	if (dumpvp->v_flag & VISSWAP)
2658 		dumphdr->dump_start = P2ROUNDUP(dumpvp_size / 5, DUMP_OFFSET);
2659 	else
2660 		dumphdr->dump_start = DUMP_OFFSET;
2661 
2662 	dumphdr->dump_flags = DF_VALID | DF_COMPLETE | DF_LIVE | DF_COMPRESSED;
2663 	dumphdr->dump_crashtime = gethrestime_sec();
2664 	dumphdr->dump_npages = 0;
2665 	dumphdr->dump_nvtop = 0;
2666 	bzero(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.bitmapsize));
2667 	dump_timeleft = dump_timeout;
2668 
2669 	if (panicstr) {
2670 		dumphdr->dump_flags &= ~DF_LIVE;
2671 		(void) VOP_DUMPCTL(dumpvp, DUMP_FREE, NULL, NULL);
2672 		(void) VOP_DUMPCTL(dumpvp, DUMP_ALLOC, NULL, NULL);
2673 		(void) vsnprintf(dumphdr->dump_panicstring, DUMP_PANICSIZE,
2674 		    panicstr, panicargs);
2675 
2676 	}
2677 
2678 	if (dump_conflags & DUMP_ALL)
2679 		content = "all";
2680 	else if (dump_conflags & DUMP_CURPROC)
2681 		content = "kernel + curproc";
2682 	else
2683 		content = "kernel";
2684 	uprintf("dumping to %s, offset %lld, content: %s\n", dumppath,
2685 	    dumphdr->dump_start, content);
2686 
2687 	/* Make sure nodename is current */
2688 	bcopy(utsname.nodename, dumphdr->dump_utsname.nodename, SYS_NMLN);
2689 
2690 	/*
2691 	 * If this is a live dump, try to open a VCHR vnode for better
2692 	 * performance. We must take care to flush the buffer cache
2693 	 * first.
2694 	 */
2695 	if (!panicstr) {
2696 		vnode_t *cdev_vp, *cmn_cdev_vp;
2697 
2698 		ASSERT(dumpbuf.cdev_vp == NULL);
2699 		cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR);
2700 		if (cdev_vp != NULL) {
2701 			cmn_cdev_vp = common_specvp(cdev_vp);
2702 			if (VOP_OPEN(&cmn_cdev_vp, FREAD | FWRITE, kcred, NULL)
2703 			    == 0) {
2704 				if (vn_has_cached_data(dumpvp))
2705 					(void) pvn_vplist_dirty(dumpvp, 0, NULL,
2706 					    B_INVAL | B_TRUNC, kcred);
2707 				dumpbuf.cdev_vp = cmn_cdev_vp;
2708 			} else {
2709 				VN_RELE(cdev_vp);
2710 			}
2711 		}
2712 	}
2713 
2714 	/*
2715 	 * Store a hires timestamp so we can look it up during debugging.
2716 	 */
2717 	lbolt_debug_entry();
2718 
2719 	/*
2720 	 * Leave room for the message and ereport save areas and terminal dump
2721 	 * header.
2722 	 */
2723 	dumpbuf.vp_limit = dumpvp_size - DUMP_LOGSIZE - DUMP_OFFSET -
2724 	    DUMP_ERPTSIZE;
2725 
2726 	/*
2727 	 * Write out the symbol table.  It's no longer compressed,
2728 	 * so its 'size' and 'csize' are equal.
2729 	 */
2730 	dumpbuf.vp_off = dumphdr->dump_ksyms = dumphdr->dump_start + PAGESIZE;
2731 	dumphdr->dump_ksyms_size = dumphdr->dump_ksyms_csize =
2732 	    ksyms_snapshot(dumpvp_ksyms_write, NULL, LONG_MAX);
2733 
2734 	/*
2735 	 * Write out the translation map.
2736 	 */
2737 	dumphdr->dump_map = dumpvp_flush();
2738 	dump_as(&kas);
2739 	dumphdr->dump_nvtop += dump_plat_addr();
2740 
2741 	/*
2742 	 * call into hat, which may have unmapped pages that also need to
2743 	 * be in the dump
2744 	 */
2745 	hat_dump();
2746 
2747 	if (dump_conflags & DUMP_ALL) {
2748 		mutex_enter(&pidlock);
2749 
2750 		for (npids = 0, p = practive; p != NULL; p = p->p_next)
2751 			dumpcfg.pids[npids++] = p->p_pid;
2752 
2753 		mutex_exit(&pidlock);
2754 
2755 		for (pidx = 0; pidx < npids; pidx++)
2756 			(void) dump_process(dumpcfg.pids[pidx]);
2757 
2758 		dump_init_memlist_walker(&mlw);
2759 		for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2760 			dump_timeleft = dump_timeout;
2761 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2762 			/*
2763 			 * Some hypervisors do not have all pages available to
2764 			 * be accessed by the guest OS.  Check for page
2765 			 * accessibility.
2766 			 */
2767 			if (plat_hold_page(pfn, PLAT_HOLD_NO_LOCK, NULL) !=
2768 			    PLAT_HOLD_OK)
2769 				continue;
2770 			BT_SET(dumpcfg.bitmap, bitnum);
2771 		}
2772 		dumphdr->dump_npages = dumpcfg.bitmapsize;
2773 		dumphdr->dump_flags |= DF_ALL;
2774 
2775 	} else if (dump_conflags & DUMP_CURPROC) {
2776 		/*
2777 		 * Determine which pid is to be dumped.  If we're panicking, we
2778 		 * dump the process associated with panic_thread (if any).  If
2779 		 * this is a live dump, we dump the process associated with
2780 		 * curthread.
2781 		 */
2782 		npids = 0;
2783 		if (panicstr) {
2784 			if (panic_thread != NULL &&
2785 			    panic_thread->t_procp != NULL &&
2786 			    panic_thread->t_procp != &p0) {
2787 				dumpcfg.pids[npids++] =
2788 				    panic_thread->t_procp->p_pid;
2789 			}
2790 		} else {
2791 			dumpcfg.pids[npids++] = curthread->t_procp->p_pid;
2792 		}
2793 
2794 		if (npids && dump_process(dumpcfg.pids[0]) == 0)
2795 			dumphdr->dump_flags |= DF_CURPROC;
2796 		else
2797 			dumphdr->dump_flags |= DF_KERNEL;
2798 
2799 	} else {
2800 		dumphdr->dump_flags |= DF_KERNEL;
2801 	}
2802 
2803 	dumphdr->dump_hashmask = (1 << highbit(dumphdr->dump_nvtop - 1)) - 1;
2804 
2805 	/*
2806 	 * Write out the pfn table.
2807 	 */
2808 	dumphdr->dump_pfn = dumpvp_flush();
2809 	dump_init_memlist_walker(&mlw);
2810 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2811 		dump_timeleft = dump_timeout;
2812 		if (!BT_TEST(dumpcfg.bitmap, bitnum))
2813 			continue;
2814 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2815 		ASSERT(pfn != PFN_INVALID);
2816 		dumpvp_write(&pfn, sizeof (pfn_t));
2817 	}
2818 	dump_plat_pfn();
2819 
2820 	/*
2821 	 * Write out all the pages.
2822 	 * Map pages, copy them handling UEs, compress, and write them out.
2823 	 * Cooperate with any helpers running on CPUs in panic_idle().
2824 	 */
2825 	dumphdr->dump_data = dumpvp_flush();
2826 
2827 	bzero(dumpcfg.helpermap, BT_SIZEOFMAP(NCPU));
2828 	ds->live = dumpcfg.clevel > 0 &&
2829 	    (dumphdr->dump_flags & DF_LIVE) != 0;
2830 
2831 	save_dump_clevel = dumpcfg.clevel;
2832 	if (panicstr)
2833 		dumpsys_get_maxmem();
2834 	else if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2835 		dumpcfg.clevel = DUMP_CLEVEL_LZJB;
2836 
2837 	dumpcfg.nhelper_used = 0;
2838 	for (hp = dumpcfg.helper; hp != hpend; hp++) {
2839 		if (hp->page == NULL) {
2840 			hp->helper = DONEHELPER;
2841 			continue;
2842 		}
2843 		++dumpcfg.nhelper_used;
2844 		hp->helper = FREEHELPER;
2845 		hp->taskqid = NULL;
2846 		hp->ds = ds;
2847 		bzero(&hp->perpage, sizeof (hp->perpage));
2848 		if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2849 			(void) BZ2_bzCompressReset(&hp->bzstream);
2850 	}
2851 
2852 	CQ_OPEN(freebufq);
2853 	CQ_OPEN(helperq);
2854 
2855 	dumpcfg.ncbuf_used = 0;
2856 	for (cp = dumpcfg.cbuf; cp != &dumpcfg.cbuf[dumpcfg.ncbuf]; cp++) {
2857 		if (cp->buf != NULL) {
2858 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2859 			++dumpcfg.ncbuf_used;
2860 		}
2861 	}
2862 
2863 	for (cp = dumpcfg.cmap; cp != &dumpcfg.cmap[dumpcfg.ncmap]; cp++)
2864 		CQ_PUT(mainq, cp, CBUF_FREEMAP);
2865 
2866 	ds->start = gethrtime();
2867 	ds->iowaitts = ds->start;
2868 
2869 	/* start helpers */
2870 	if (ds->live) {
2871 		int n = dumpcfg.nhelper_used;
2872 		int pri = MINCLSYSPRI - 25;
2873 
2874 		livetaskq = taskq_create("LiveDump", n, pri, n, n,
2875 		    TASKQ_PREPOPULATE);
2876 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2877 			if (hp->page == NULL)
2878 				continue;
2879 			hp->helper = hp - dumpcfg.helper;
2880 			hp->taskqid = taskq_dispatch(livetaskq,
2881 			    dumpsys_live_helper, (void *)hp, TQ_NOSLEEP);
2882 		}
2883 
2884 	} else {
2885 		if (panicstr)
2886 			kmem_dump_begin();
2887 		dumpcfg.helpers_wanted = dumpcfg.clevel > 0;
2888 		dumpsys_spinunlock(&dumpcfg.helper_lock);
2889 	}
2890 
2891 	/* run main task */
2892 	dumpsys_main_task(ds);
2893 
2894 	ds->elapsed = gethrtime() - ds->start;
2895 	if (ds->elapsed < 1)
2896 		ds->elapsed = 1;
2897 
2898 	if (livetaskq != NULL)
2899 		taskq_destroy(livetaskq);
2900 
2901 	if (ds->neednl) {
2902 		uprintf("\n");
2903 		ds->neednl = 0;
2904 	}
2905 
2906 	/* record actual pages dumped */
2907 	dumphdr->dump_npages = ds->npages;
2908 
2909 	/* platform-specific data */
2910 	dumphdr->dump_npages += dump_plat_data(dumpcfg.cbuf[0].buf);
2911 
2912 	/* note any errors by clearing DF_COMPLETE */
2913 	if (dump_ioerr || ds->npages < dumphdr->dump_npages)
2914 		dumphdr->dump_flags &= ~DF_COMPLETE;
2915 
2916 	/* end of stream blocks */
2917 	datatag = 0;
2918 	dumpvp_write(&datatag, sizeof (datatag));
2919 
2920 	bzero(&datahdr, sizeof (datahdr));
2921 
2922 	/* buffer for metrics */
2923 	buf = dumpcfg.cbuf[0].buf;
2924 	size = MIN(dumpcfg.cbuf[0].size, DUMP_OFFSET - sizeof (dumphdr_t) -
2925 	    sizeof (dumpdatahdr_t));
2926 
2927 	/* finish the kmem intercepts, collect kmem verbose info */
2928 	if (panicstr) {
2929 		datahdr.dump_metrics = kmem_dump_finish(buf, size);
2930 		buf += datahdr.dump_metrics;
2931 		size -= datahdr.dump_metrics;
2932 	}
2933 
2934 	/* record in the header whether this is a fault-management panic */
2935 	if (panicstr)
2936 		dumphdr->dump_fm_panic = is_fm_panic();
2937 
2938 	/* compression info in data header */
2939 	datahdr.dump_datahdr_magic = DUMP_DATAHDR_MAGIC;
2940 	datahdr.dump_datahdr_version = DUMP_DATAHDR_VERSION;
2941 	datahdr.dump_maxcsize = CBUF_SIZE;
2942 	datahdr.dump_maxrange = CBUF_MAPSIZE / PAGESIZE;
2943 	datahdr.dump_nstreams = dumpcfg.nhelper_used;
2944 	datahdr.dump_clevel = dumpcfg.clevel;
2945 #ifdef COLLECT_METRICS
2946 	if (dump_metrics_on)
2947 		datahdr.dump_metrics += dumpsys_metrics(ds, buf, size);
2948 #endif
2949 	datahdr.dump_data_csize = dumpvp_flush() - dumphdr->dump_data;
2950 
2951 	/*
2952 	 * Write out the initial and terminal dump headers.
2953 	 */
2954 	dumpbuf.vp_off = dumphdr->dump_start;
2955 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
2956 	(void) dumpvp_flush();
2957 
2958 	dumpbuf.vp_limit = dumpvp_size;
2959 	dumpbuf.vp_off = dumpbuf.vp_limit - DUMP_OFFSET;
2960 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
2961 	dumpvp_write(&datahdr, sizeof (dumpdatahdr_t));
2962 	dumpvp_write(dumpcfg.cbuf[0].buf, datahdr.dump_metrics);
2963 
2964 	(void) dumpvp_flush();
2965 
2966 	uprintf("\r%3d%% done: %llu pages dumped, ",
2967 	    ds->percent_done, (u_longlong_t)ds->npages);
2968 
2969 	if (dump_ioerr == 0) {
2970 		uprintf("dump succeeded\n");
2971 	} else {
2972 		uprintf("dump failed: error %d\n", dump_ioerr);
2973 #ifdef DEBUG
2974 		if (panicstr)
2975 			debug_enter("dump failed");
2976 #endif
2977 	}
2978 
2979 	/*
2980 	 * Write out all undelivered messages.  This has to be the *last*
2981 	 * thing we do because the dump process itself emits messages.
2982 	 */
2983 	if (panicstr) {
2984 		dump_summary();
2985 		dump_ereports();
2986 		dump_messages();
2987 	}
2988 
2989 	delay(2 * hz);	/* let people see the 'done' message */
2990 	dump_timeleft = 0;
2991 	dump_ioerr = 0;
2992 
2993 	/* restore settings after live dump completes */
2994 	if (!panicstr) {
2995 		dumpcfg.clevel = save_dump_clevel;
2996 
2997 		/* release any VCHR open of the dump device */
2998 		if (dumpbuf.cdev_vp != NULL) {
2999 			(void) VOP_CLOSE(dumpbuf.cdev_vp, FREAD | FWRITE, 1, 0,
3000 			    kcred, NULL);
3001 			VN_RELE(dumpbuf.cdev_vp);
3002 			dumpbuf.cdev_vp = NULL;
3003 		}
3004 	}
3005 }
3006 
3007 /*
3008  * This function is called whenever the memory size, as represented
3009  * by the phys_install list, changes.
3010  */
3011 void
3012 dump_resize()
3013 {
3014 	mutex_enter(&dump_lock);
3015 	dumphdr_init();
3016 	dumpbuf_resize();
3017 	dump_update_clevel();
3018 	mutex_exit(&dump_lock);
3019 }
3020 
3021 /*
3022  * This function allows for dynamic resizing of a dump area. It assumes that
3023  * the underlying device has update its appropriate size(9P).
3024  */
3025 int
3026 dumpvp_resize()
3027 {
3028 	int error;
3029 	vattr_t vattr;
3030 
3031 	mutex_enter(&dump_lock);
3032 	vattr.va_mask = AT_SIZE;
3033 	if ((error = VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL)) != 0) {
3034 		mutex_exit(&dump_lock);
3035 		return (error);
3036 	}
3037 
3038 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE) {
3039 		mutex_exit(&dump_lock);
3040 		return (ENOSPC);
3041 	}
3042 
3043 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
3044 	mutex_exit(&dump_lock);
3045 	return (0);
3046 }
3047 
3048 int
3049 dump_set_uuid(const char *uuidstr)
3050 {
3051 	const char *ptr;
3052 	int i;
3053 
3054 	if (uuidstr == NULL || strnlen(uuidstr, 36 + 1) != 36)
3055 		return (EINVAL);
3056 
3057 	/* uuid_parse is not common code so check manually */
3058 	for (i = 0, ptr = uuidstr; i < 36; i++, ptr++) {
3059 		switch (i) {
3060 		case 8:
3061 		case 13:
3062 		case 18:
3063 		case 23:
3064 			if (*ptr != '-')
3065 				return (EINVAL);
3066 			break;
3067 
3068 		default:
3069 			if (!isxdigit(*ptr))
3070 				return (EINVAL);
3071 			break;
3072 		}
3073 	}
3074 
3075 	if (dump_osimage_uuid[0] != '\0')
3076 		return (EALREADY);
3077 
3078 	(void) strncpy(dump_osimage_uuid, uuidstr, 36 + 1);
3079 
3080 	cmn_err(CE_CONT, "?This Solaris instance has UUID %s\n",
3081 	    dump_osimage_uuid);
3082 
3083 	return (0);
3084 }
3085 
3086 const char *
3087 dump_get_uuid(void)
3088 {
3089 	return (dump_osimage_uuid[0] != '\0' ? dump_osimage_uuid : "");
3090 }
3091