xref: /titanic_41/usr/src/uts/common/os/dumpsubr.c (revision 0a47c91c895e274dd0990009919e30e984364a8b)
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  */
25 
26 #include <sys/types.h>
27 #include <sys/param.h>
28 #include <sys/systm.h>
29 #include <sys/vm.h>
30 #include <sys/proc.h>
31 #include <sys/file.h>
32 #include <sys/conf.h>
33 #include <sys/kmem.h>
34 #include <sys/mem.h>
35 #include <sys/mman.h>
36 #include <sys/vnode.h>
37 #include <sys/errno.h>
38 #include <sys/memlist.h>
39 #include <sys/dumphdr.h>
40 #include <sys/dumpadm.h>
41 #include <sys/ksyms.h>
42 #include <sys/compress.h>
43 #include <sys/stream.h>
44 #include <sys/strsun.h>
45 #include <sys/cmn_err.h>
46 #include <sys/bitmap.h>
47 #include <sys/modctl.h>
48 #include <sys/utsname.h>
49 #include <sys/systeminfo.h>
50 #include <sys/vmem.h>
51 #include <sys/log.h>
52 #include <sys/var.h>
53 #include <sys/debug.h>
54 #include <sys/sunddi.h>
55 #include <fs/fs_subr.h>
56 #include <sys/fs/snode.h>
57 #include <sys/ontrap.h>
58 #include <sys/panic.h>
59 #include <sys/dkio.h>
60 #include <sys/vtoc.h>
61 #include <sys/errorq.h>
62 #include <sys/fm/util.h>
63 #include <sys/fs/zfs.h>
64 
65 #include <vm/hat.h>
66 #include <vm/as.h>
67 #include <vm/page.h>
68 #include <vm/pvn.h>
69 #include <vm/seg.h>
70 #include <vm/seg_kmem.h>
71 #include <sys/clock_impl.h>
72 #include <sys/hold_page.h>
73 
74 #include <bzip2/bzlib.h>
75 
76 /*
77  * Crash dump time is dominated by disk write time.  To reduce this,
78  * the stronger compression method bzip2 is applied to reduce the dump
79  * size and hence reduce I/O time.  However, bzip2 is much more
80  * computationally expensive than the existing lzjb algorithm, so to
81  * avoid increasing compression time, CPUs that are otherwise idle
82  * during panic are employed to parallelize the compression task.
83  * Many helper CPUs are needed to prevent bzip2 from being a
84  * bottleneck, and on systems with too few CPUs, the lzjb algorithm is
85  * parallelized instead. Lastly, I/O and compression are performed by
86  * different CPUs, and are hence overlapped in time, unlike the older
87  * serial code.
88  *
89  * Another important consideration is the speed of the dump
90  * device. Faster disks need less CPUs in order to benefit from
91  * parallel lzjb versus parallel bzip2. Therefore, the CPU count
92  * threshold for switching from parallel lzjb to paralled bzip2 is
93  * elevated for faster disks. The dump device speed is adduced from
94  * the setting for dumpbuf.iosize, see dump_update_clevel.
95  */
96 
97 /*
98  * exported vars
99  */
100 kmutex_t	dump_lock;		/* lock for dump configuration */
101 dumphdr_t	*dumphdr;		/* dump header */
102 int		dump_conflags = DUMP_KERNEL; /* dump configuration flags */
103 vnode_t		*dumpvp;		/* dump device vnode pointer */
104 u_offset_t	dumpvp_size;		/* size of dump device, in bytes */
105 char		*dumppath;		/* pathname of dump device */
106 int		dump_timeout = 120;	/* timeout for dumping pages */
107 int		dump_timeleft;		/* portion of dump_timeout remaining */
108 int		dump_ioerr;		/* dump i/o error */
109 int		dump_check_used;	/* enable check for used pages */
110 char	    *dump_stack_scratch; /* scratch area for saving stack summary */
111 
112 /*
113  * Tunables for dump compression and parallelism. These can be set via
114  * /etc/system.
115  *
116  * dump_ncpu_low	number of helpers for parallel lzjb
117  *	This is also the minimum configuration.
118  *
119  * dump_bzip2_level	bzip2 compression level: 1-9
120  *	Higher numbers give greater compression, but take more memory
121  *	and time. Memory used per helper is ~(dump_bzip2_level * 1MB).
122  *
123  * dump_plat_mincpu	the cross-over limit for using bzip2 (per platform):
124  *	if dump_plat_mincpu == 0, then always do single threaded dump
125  *	if ncpu >= dump_plat_mincpu then try to use bzip2
126  *
127  * dump_metrics_on	if set, metrics are collected in the kernel, passed
128  *	to savecore via the dump file, and recorded by savecore in
129  *	METRICS.txt.
130  */
131 uint_t dump_ncpu_low = 4;	/* minimum config for parallel lzjb */
132 uint_t dump_bzip2_level = 1;	/* bzip2 level (1-9) */
133 
134 /* Use dump_plat_mincpu_default unless this variable is set by /etc/system */
135 #define	MINCPU_NOT_SET	((uint_t)-1)
136 uint_t dump_plat_mincpu = MINCPU_NOT_SET;
137 
138 /* tunables for pre-reserved heap */
139 uint_t dump_kmem_permap = 1024;
140 uint_t dump_kmem_pages = 8;
141 
142 /* Define multiple buffers per helper to avoid stalling */
143 #define	NCBUF_PER_HELPER	2
144 #define	NCMAP_PER_HELPER	4
145 
146 /* minimum number of helpers configured */
147 #define	MINHELPERS	(dump_ncpu_low)
148 #define	MINCBUFS	(MINHELPERS * NCBUF_PER_HELPER)
149 
150 /*
151  * Define constant parameters.
152  *
153  * CBUF_SIZE		size of an output buffer
154  *
155  * CBUF_MAPSIZE		size of virtual range for mapping pages
156  *
157  * CBUF_MAPNP		size of virtual range in pages
158  *
159  */
160 #define	DUMP_1KB	((size_t)1 << 10)
161 #define	DUMP_1MB	((size_t)1 << 20)
162 #define	CBUF_SIZE	((size_t)1 << 17)
163 #define	CBUF_MAPSHIFT	(22)
164 #define	CBUF_MAPSIZE	((size_t)1 << CBUF_MAPSHIFT)
165 #define	CBUF_MAPNP	((size_t)1 << (CBUF_MAPSHIFT - PAGESHIFT))
166 
167 /*
168  * Compression metrics are accumulated nano-second subtotals. The
169  * results are normalized by the number of pages dumped. A report is
170  * generated when dumpsys() completes and is saved in the dump image
171  * after the trailing dump header.
172  *
173  * Metrics are always collected. Set the variable dump_metrics_on to
174  * cause metrics to be saved in the crash file, where savecore will
175  * save it in the file METRICS.txt.
176  */
177 #define	PERPAGES \
178 	PERPAGE(bitmap) PERPAGE(map) PERPAGE(unmap) \
179 	PERPAGE(copy) PERPAGE(compress) \
180 	PERPAGE(write) \
181 	PERPAGE(inwait) PERPAGE(outwait)
182 
183 typedef struct perpage {
184 #define	PERPAGE(x) hrtime_t x;
185 	PERPAGES
186 #undef PERPAGE
187 } perpage_t;
188 
189 /*
190  * This macro controls the code generation for collecting dump
191  * performance information. By default, the code is generated, but
192  * automatic saving of the information is disabled. If dump_metrics_on
193  * is set to 1, the timing information is passed to savecore via the
194  * crash file, where it is appended to the file dump-dir/METRICS.txt.
195  */
196 #define	COLLECT_METRICS
197 
198 #ifdef COLLECT_METRICS
199 uint_t dump_metrics_on = 0;	/* set to 1 to enable recording metrics */
200 
201 #define	HRSTART(v, m)		v##ts.m = gethrtime()
202 #define	HRSTOP(v, m)		v.m += gethrtime() - v##ts.m
203 #define	HRBEGIN(v, m, s)	v##ts.m = gethrtime(); v.size += s
204 #define	HREND(v, m)		v.m += gethrtime() - v##ts.m
205 #define	HRNORM(v, m, n)		v.m /= (n)
206 
207 #else
208 #define	HRSTART(v, m)
209 #define	HRSTOP(v, m)
210 #define	HRBEGIN(v, m, s)
211 #define	HREND(v, m)
212 #define	HRNORM(v, m, n)
213 #endif	/* COLLECT_METRICS */
214 
215 /*
216  * Buffers for copying and compressing memory pages.
217  *
218  * cbuf_t buffer controllers: used for both input and output.
219  *
220  * The buffer state indicates how it is being used:
221  *
222  * CBUF_FREEMAP: CBUF_MAPSIZE virtual address range is available for
223  * mapping input pages.
224  *
225  * CBUF_INREADY: input pages are mapped and ready for compression by a
226  * helper.
227  *
228  * CBUF_USEDMAP: mapping has been consumed by a helper. Needs unmap.
229  *
230  * CBUF_FREEBUF: CBUF_SIZE output buffer, which is available.
231  *
232  * CBUF_WRITE: CBUF_SIZE block of compressed pages from a helper,
233  * ready to write out.
234  *
235  * CBUF_ERRMSG: CBUF_SIZE block of error messages from a helper
236  * (reports UE errors.)
237  */
238 
239 typedef enum cbufstate {
240 	CBUF_FREEMAP,
241 	CBUF_INREADY,
242 	CBUF_USEDMAP,
243 	CBUF_FREEBUF,
244 	CBUF_WRITE,
245 	CBUF_ERRMSG
246 } cbufstate_t;
247 
248 typedef struct cbuf cbuf_t;
249 
250 struct cbuf {
251 	cbuf_t *next;			/* next in list */
252 	cbufstate_t state;		/* processing state */
253 	size_t used;			/* amount used */
254 	size_t size;			/* mem size */
255 	char *buf;			/* kmem or vmem */
256 	pgcnt_t pagenum;		/* index to pfn map */
257 	pgcnt_t bitnum;			/* first set bitnum */
258 	pfn_t pfn;			/* first pfn in mapped range */
259 	int off;			/* byte offset to first pfn */
260 };
261 
262 static char dump_osimage_uuid[36 + 1];
263 
264 #define	isdigit(ch)	((ch) >= '0' && (ch) <= '9')
265 #define	isxdigit(ch)	(isdigit(ch) || ((ch) >= 'a' && (ch) <= 'f') || \
266 			((ch) >= 'A' && (ch) <= 'F'))
267 
268 /*
269  * cqueue_t queues: a uni-directional channel for communication
270  * from the master to helper tasks or vice-versa using put and
271  * get primitives. Both mappings and data buffers are passed via
272  * queues. Producers close a queue when done. The number of
273  * active producers is reference counted so the consumer can
274  * detect end of data. Concurrent access is mediated by atomic
275  * operations for panic dump, or mutex/cv for live dump.
276  *
277  * There a four queues, used as follows:
278  *
279  * Queue		Dataflow		NewState
280  * --------------------------------------------------
281  * mainq		master -> master	FREEMAP
282  * master has initialized or unmapped an input buffer
283  * --------------------------------------------------
284  * helperq		master -> helper	INREADY
285  * master has mapped input for use by helper
286  * --------------------------------------------------
287  * mainq		master <- helper	USEDMAP
288  * helper is done with input
289  * --------------------------------------------------
290  * freebufq		master -> helper	FREEBUF
291  * master has initialized or written an output buffer
292  * --------------------------------------------------
293  * mainq		master <- helper	WRITE
294  * block of compressed pages from a helper
295  * --------------------------------------------------
296  * mainq		master <- helper	ERRMSG
297  * error messages from a helper (memory error case)
298  * --------------------------------------------------
299  * writerq		master <- master	WRITE
300  * non-blocking queue of blocks to write
301  * --------------------------------------------------
302  */
303 typedef struct cqueue {
304 	cbuf_t *volatile first;		/* first in list */
305 	cbuf_t *last;			/* last in list */
306 	hrtime_t ts;			/* timestamp */
307 	hrtime_t empty;			/* total time empty */
308 	kmutex_t mutex;			/* live state lock */
309 	kcondvar_t cv;			/* live wait var */
310 	lock_t spinlock;		/* panic mode spin lock */
311 	volatile uint_t open;		/* producer ref count */
312 } cqueue_t;
313 
314 /*
315  * Convenience macros for using the cqueue functions
316  * Note that the caller must have defined "dumpsync_t *ds"
317  */
318 #define	CQ_IS_EMPTY(q)					\
319 	(ds->q.first == NULL)
320 
321 #define	CQ_OPEN(q)					\
322 	atomic_inc_uint(&ds->q.open)
323 
324 #define	CQ_CLOSE(q)					\
325 	dumpsys_close_cq(&ds->q, ds->live)
326 
327 #define	CQ_PUT(q, cp, st)				\
328 	dumpsys_put_cq(&ds->q, cp, st, ds->live)
329 
330 #define	CQ_GET(q)					\
331 	dumpsys_get_cq(&ds->q, ds->live)
332 
333 /*
334  * Dynamic state when dumpsys() is running.
335  */
336 typedef struct dumpsync {
337 	pgcnt_t npages;			/* subtotal of pages dumped */
338 	pgcnt_t pages_mapped;		/* subtotal of pages mapped */
339 	pgcnt_t pages_used;		/* subtotal of pages used per map */
340 	size_t nwrite;			/* subtotal of bytes written */
341 	uint_t live;			/* running live dump */
342 	uint_t neednl;			/* will need to print a newline */
343 	uint_t percent;			/* dump progress */
344 	uint_t percent_done;		/* dump progress reported */
345 	cqueue_t freebufq;		/* free kmem bufs for writing */
346 	cqueue_t mainq;			/* input for main task */
347 	cqueue_t helperq;		/* input for helpers */
348 	cqueue_t writerq;		/* input for writer */
349 	hrtime_t start;			/* start time */
350 	hrtime_t elapsed;		/* elapsed time when completed */
351 	hrtime_t iotime;		/* time spent writing nwrite bytes */
352 	hrtime_t iowait;		/* time spent waiting for output */
353 	hrtime_t iowaitts;		/* iowait timestamp */
354 	perpage_t perpage;		/* metrics */
355 	perpage_t perpagets;
356 	int dumpcpu;			/* master cpu */
357 } dumpsync_t;
358 
359 static dumpsync_t dumpsync;		/* synchronization vars */
360 
361 /*
362  * helper_t helpers: contains the context for a stream. CPUs run in
363  * parallel at dump time; each CPU creates a single stream of
364  * compression data.  Stream data is divided into CBUF_SIZE blocks.
365  * The blocks are written in order within a stream. But, blocks from
366  * multiple streams can be interleaved. Each stream is identified by a
367  * unique tag.
368  */
369 typedef struct helper {
370 	int helper;			/* bound helper id */
371 	int tag;			/* compression stream tag */
372 	perpage_t perpage;		/* per page metrics */
373 	perpage_t perpagets;		/* per page metrics (timestamps) */
374 	taskqid_t taskqid;		/* live dump task ptr */
375 	int in, out;			/* buffer offsets */
376 	cbuf_t *cpin, *cpout, *cperr;	/* cbuf objects in process */
377 	dumpsync_t *ds;			/* pointer to sync vars */
378 	size_t used;			/* counts input consumed */
379 	char *page;			/* buffer for page copy */
380 	char *lzbuf;			/* lzjb output */
381 	bz_stream bzstream;		/* bzip2 state */
382 } helper_t;
383 
384 #define	MAINHELPER	(-1)		/* helper is also the main task */
385 #define	FREEHELPER	(-2)		/* unbound helper */
386 #define	DONEHELPER	(-3)		/* helper finished */
387 
388 /*
389  * configuration vars for dumpsys
390  */
391 typedef struct dumpcfg {
392 	int	threshold;	/* ncpu threshold for bzip2 */
393 	int	nhelper;	/* number of helpers */
394 	int	nhelper_used;	/* actual number of helpers used */
395 	int	ncmap;		/* number VA pages for compression */
396 	int	ncbuf;		/* number of bufs for compression */
397 	int	ncbuf_used;	/* number of bufs in use */
398 	uint_t	clevel;		/* dump compression level */
399 	helper_t *helper;	/* array of helpers */
400 	cbuf_t	*cmap;		/* array of input (map) buffers */
401 	cbuf_t	*cbuf;		/* array of output  buffers */
402 	ulong_t	*helpermap;	/* set of dumpsys helper CPU ids */
403 	ulong_t	*bitmap;	/* bitmap for marking pages to dump */
404 	ulong_t	*rbitmap;	/* bitmap for used CBUF_MAPSIZE ranges */
405 	pgcnt_t	bitmapsize;	/* size of bitmap */
406 	pgcnt_t	rbitmapsize;	/* size of bitmap for ranges */
407 	pgcnt_t found4m;	/* number ranges allocated by dump */
408 	pgcnt_t foundsm;	/* number small pages allocated by dump */
409 	pid_t	*pids;		/* list of process IDs at dump time */
410 	size_t	maxsize;	/* memory size needed at dump time */
411 	size_t	maxvmsize;	/* size of reserved VM */
412 	char	*maxvm;		/* reserved VM for spare pages */
413 	lock_t	helper_lock;	/* protect helper state */
414 	char	helpers_wanted;	/* flag to enable parallelism */
415 } dumpcfg_t;
416 
417 static dumpcfg_t dumpcfg;	/* config vars */
418 
419 /*
420  * The dump I/O buffer.
421  *
422  * There is one I/O buffer used by dumpvp_write and dumvp_flush. It is
423  * sized according to the optimum device transfer speed.
424  */
425 typedef struct dumpbuf {
426 	vnode_t	*cdev_vp;	/* VCHR open of the dump device */
427 	len_t	vp_limit;	/* maximum write offset */
428 	offset_t vp_off;	/* current dump device offset */
429 	char	*cur;		/* dump write pointer */
430 	char	*start;		/* dump buffer address */
431 	char	*end;		/* dump buffer end */
432 	size_t	size;		/* size of dumpbuf in bytes */
433 	size_t	iosize;		/* best transfer size for device */
434 } dumpbuf_t;
435 
436 dumpbuf_t dumpbuf;		/* I/O buffer */
437 
438 /*
439  * The dump I/O buffer must be at least one page, at most xfer_size
440  * bytes, and should scale with physmem in between.  The transfer size
441  * passed in will either represent a global default (maxphys) or the
442  * best size for the device.  The size of the dumpbuf I/O buffer is
443  * limited by dumpbuf_limit (8MB by default) because the dump
444  * performance saturates beyond a certain size.  The default is to
445  * select 1/4096 of the memory.
446  */
447 static int	dumpbuf_fraction = 12;	/* memory size scale factor */
448 static size_t	dumpbuf_limit = 8 * DUMP_1MB;	/* max I/O buf size */
449 
450 static size_t
451 dumpbuf_iosize(size_t xfer_size)
452 {
453 	size_t iosize = ptob(physmem >> dumpbuf_fraction);
454 
455 	if (iosize < PAGESIZE)
456 		iosize = PAGESIZE;
457 	else if (iosize > xfer_size)
458 		iosize = xfer_size;
459 	if (iosize > dumpbuf_limit)
460 		iosize = dumpbuf_limit;
461 	return (iosize & PAGEMASK);
462 }
463 
464 /*
465  * resize the I/O buffer
466  */
467 static void
468 dumpbuf_resize(void)
469 {
470 	char *old_buf = dumpbuf.start;
471 	size_t old_size = dumpbuf.size;
472 	char *new_buf;
473 	size_t new_size;
474 
475 	ASSERT(MUTEX_HELD(&dump_lock));
476 
477 	new_size = dumpbuf_iosize(MAX(dumpbuf.iosize, maxphys));
478 	if (new_size <= old_size)
479 		return; /* no need to reallocate buffer */
480 
481 	new_buf = kmem_alloc(new_size, KM_SLEEP);
482 	dumpbuf.size = new_size;
483 	dumpbuf.start = new_buf;
484 	dumpbuf.end = new_buf + new_size;
485 	kmem_free(old_buf, old_size);
486 }
487 
488 /*
489  * dump_update_clevel is called when dumpadm configures the dump device.
490  * 	Calculate number of helpers and buffers.
491  * 	Allocate the minimum configuration for now.
492  *
493  * When the dump file is configured we reserve a minimum amount of
494  * memory for use at crash time. But we reserve VA for all the memory
495  * we really want in order to do the fastest dump possible. The VA is
496  * backed by pages not being dumped, according to the bitmap. If
497  * there is insufficient spare memory, however, we fall back to the
498  * minimum.
499  *
500  * Live dump (savecore -L) always uses the minimum config.
501  *
502  * clevel 0 is single threaded lzjb
503  * clevel 1 is parallel lzjb
504  * clevel 2 is parallel bzip2
505  *
506  * The ncpu threshold is selected with dump_plat_mincpu.
507  * On OPL, set_platform_defaults() overrides the sun4u setting.
508  * The actual values are defined via DUMP_PLAT_*_MINCPU macros.
509  *
510  * Architecture		Threshold	Algorithm
511  * sun4u       		<  51		parallel lzjb
512  * sun4u       		>= 51		parallel bzip2(*)
513  * sun4u OPL   		<  8		parallel lzjb
514  * sun4u OPL   		>= 8		parallel bzip2(*)
515  * sun4v       		<  128		parallel lzjb
516  * sun4v       		>= 128		parallel bzip2(*)
517  * x86			< 11		parallel lzjb
518  * x86			>= 11		parallel bzip2(*)
519  * 32-bit      		N/A		single-threaded lzjb
520  *
521  * (*) bzip2 is only chosen if there is sufficient available
522  * memory for buffers at dump time. See dumpsys_get_maxmem().
523  *
524  * Faster dump devices have larger I/O buffers. The threshold value is
525  * increased according to the size of the dump I/O buffer, because
526  * parallel lzjb performs better with faster disks. For buffers >= 1MB
527  * the threshold is 3X; for buffers >= 256K threshold is 2X.
528  *
529  * For parallel dumps, the number of helpers is ncpu-1. The CPU
530  * running panic runs the main task. For single-threaded dumps, the
531  * panic CPU does lzjb compression (it is tagged as MAINHELPER.)
532  *
533  * Need multiple buffers per helper so that they do not block waiting
534  * for the main task.
535  *				parallel	single-threaded
536  * Number of output buffers:	nhelper*2		1
537  * Number of mapping buffers:	nhelper*4		1
538  *
539  */
540 static void
541 dump_update_clevel()
542 {
543 	int tag;
544 	size_t bz2size;
545 	helper_t *hp, *hpend;
546 	cbuf_t *cp, *cpend;
547 	dumpcfg_t *old = &dumpcfg;
548 	dumpcfg_t newcfg = *old;
549 	dumpcfg_t *new = &newcfg;
550 
551 	ASSERT(MUTEX_HELD(&dump_lock));
552 
553 	/*
554 	 * Free the previously allocated bufs and VM.
555 	 */
556 	if (old->helper != NULL) {
557 
558 		/* helpers */
559 		hpend = &old->helper[old->nhelper];
560 		for (hp = old->helper; hp != hpend; hp++) {
561 			if (hp->lzbuf != NULL)
562 				kmem_free(hp->lzbuf, PAGESIZE);
563 			if (hp->page != NULL)
564 				kmem_free(hp->page, PAGESIZE);
565 		}
566 		kmem_free(old->helper, old->nhelper * sizeof (helper_t));
567 
568 		/* VM space for mapping pages */
569 		cpend = &old->cmap[old->ncmap];
570 		for (cp = old->cmap; cp != cpend; cp++)
571 			vmem_xfree(heap_arena, cp->buf, CBUF_MAPSIZE);
572 		kmem_free(old->cmap, old->ncmap * sizeof (cbuf_t));
573 
574 		/* output bufs */
575 		cpend = &old->cbuf[old->ncbuf];
576 		for (cp = old->cbuf; cp != cpend; cp++)
577 			if (cp->buf != NULL)
578 				kmem_free(cp->buf, cp->size);
579 		kmem_free(old->cbuf, old->ncbuf * sizeof (cbuf_t));
580 
581 		/* reserved VM for dumpsys_get_maxmem */
582 		if (old->maxvmsize > 0)
583 			vmem_xfree(heap_arena, old->maxvm, old->maxvmsize);
584 	}
585 
586 	/*
587 	 * Allocate memory and VM.
588 	 * One CPU runs dumpsys, the rest are helpers.
589 	 */
590 	new->nhelper = ncpus - 1;
591 	if (new->nhelper < 1)
592 		new->nhelper = 1;
593 
594 	if (new->nhelper > DUMP_MAX_NHELPER)
595 		new->nhelper = DUMP_MAX_NHELPER;
596 
597 	/* use platform default, unless /etc/system overrides */
598 	if (dump_plat_mincpu == MINCPU_NOT_SET)
599 		dump_plat_mincpu = dump_plat_mincpu_default;
600 
601 	/* increase threshold for faster disks */
602 	new->threshold = dump_plat_mincpu;
603 	if (dumpbuf.iosize >= DUMP_1MB)
604 		new->threshold *= 3;
605 	else if (dumpbuf.iosize >= (256 * DUMP_1KB))
606 		new->threshold *= 2;
607 
608 	/* figure compression level based upon the computed threshold. */
609 	if (dump_plat_mincpu == 0 || new->nhelper < 2) {
610 		new->clevel = 0;
611 		new->nhelper = 1;
612 	} else if ((new->nhelper + 1) >= new->threshold) {
613 		new->clevel = DUMP_CLEVEL_BZIP2;
614 	} else {
615 		new->clevel = DUMP_CLEVEL_LZJB;
616 	}
617 
618 	if (new->clevel == 0) {
619 		new->ncbuf = 1;
620 		new->ncmap = 1;
621 	} else {
622 		new->ncbuf = NCBUF_PER_HELPER * new->nhelper;
623 		new->ncmap = NCMAP_PER_HELPER * new->nhelper;
624 	}
625 
626 	/*
627 	 * Allocate new data structures and buffers for MINHELPERS,
628 	 * and also figure the max desired size.
629 	 */
630 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
631 	new->maxsize = 0;
632 	new->maxvmsize = 0;
633 	new->maxvm = NULL;
634 	tag = 1;
635 	new->helper = kmem_zalloc(new->nhelper * sizeof (helper_t), KM_SLEEP);
636 	hpend = &new->helper[new->nhelper];
637 	for (hp = new->helper; hp != hpend; hp++) {
638 		hp->tag = tag++;
639 		if (hp < &new->helper[MINHELPERS]) {
640 			hp->lzbuf = kmem_alloc(PAGESIZE, KM_SLEEP);
641 			hp->page = kmem_alloc(PAGESIZE, KM_SLEEP);
642 		} else if (new->clevel < DUMP_CLEVEL_BZIP2) {
643 			new->maxsize += 2 * PAGESIZE;
644 		} else {
645 			new->maxsize += PAGESIZE;
646 		}
647 		if (new->clevel >= DUMP_CLEVEL_BZIP2)
648 			new->maxsize += bz2size;
649 	}
650 
651 	new->cbuf = kmem_zalloc(new->ncbuf * sizeof (cbuf_t), KM_SLEEP);
652 	cpend = &new->cbuf[new->ncbuf];
653 	for (cp = new->cbuf; cp != cpend; cp++) {
654 		cp->state = CBUF_FREEBUF;
655 		cp->size = CBUF_SIZE;
656 		if (cp < &new->cbuf[MINCBUFS])
657 			cp->buf = kmem_alloc(cp->size, KM_SLEEP);
658 		else
659 			new->maxsize += cp->size;
660 	}
661 
662 	new->cmap = kmem_zalloc(new->ncmap * sizeof (cbuf_t), KM_SLEEP);
663 	cpend = &new->cmap[new->ncmap];
664 	for (cp = new->cmap; cp != cpend; cp++) {
665 		cp->state = CBUF_FREEMAP;
666 		cp->size = CBUF_MAPSIZE;
667 		cp->buf = vmem_xalloc(heap_arena, CBUF_MAPSIZE, CBUF_MAPSIZE,
668 		    0, 0, NULL, NULL, VM_SLEEP);
669 	}
670 
671 	/* reserve VA to be backed with spare pages at crash time */
672 	if (new->maxsize > 0) {
673 		new->maxsize = P2ROUNDUP(new->maxsize, PAGESIZE);
674 		new->maxvmsize = P2ROUNDUP(new->maxsize, CBUF_MAPSIZE);
675 		new->maxvm = vmem_xalloc(heap_arena, new->maxvmsize,
676 		    CBUF_MAPSIZE, 0, 0, NULL, NULL, VM_SLEEP);
677 	}
678 
679 	/*
680 	 * Reserve memory for kmem allocation calls made during crash
681 	 * dump.  The hat layer allocates memory for each mapping
682 	 * created, and the I/O path allocates buffers and data structs.
683 	 * Add a few pages for safety.
684 	 */
685 	kmem_dump_init((new->ncmap * dump_kmem_permap) +
686 	    (dump_kmem_pages * PAGESIZE));
687 
688 	/* set new config pointers */
689 	*old = *new;
690 }
691 
692 /*
693  * Define a struct memlist walker to optimize bitnum to pfn
694  * lookup. The walker maintains the state of the list traversal.
695  */
696 typedef struct dumpmlw {
697 	struct memlist	*mp;		/* current memlist */
698 	pgcnt_t		basenum;	/* bitnum base offset */
699 	pgcnt_t		mppages;	/* current memlist size */
700 	pgcnt_t		mpleft;		/* size to end of current memlist */
701 	pfn_t		mpaddr;		/* first pfn in memlist */
702 } dumpmlw_t;
703 
704 /* initialize the walker */
705 static inline void
706 dump_init_memlist_walker(dumpmlw_t *pw)
707 {
708 	pw->mp = phys_install;
709 	pw->basenum = 0;
710 	pw->mppages = pw->mp->ml_size >> PAGESHIFT;
711 	pw->mpleft = pw->mppages;
712 	pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
713 }
714 
715 /*
716  * Lookup pfn given bitnum. The memlist can be quite long on some
717  * systems (e.g.: one per board). To optimize sequential lookups, the
718  * caller initializes and presents a memlist walker.
719  */
720 static pfn_t
721 dump_bitnum_to_pfn(pgcnt_t bitnum, dumpmlw_t *pw)
722 {
723 	bitnum -= pw->basenum;
724 	while (pw->mp != NULL) {
725 		if (bitnum < pw->mppages) {
726 			pw->mpleft = pw->mppages - bitnum;
727 			return (pw->mpaddr + bitnum);
728 		}
729 		bitnum -= pw->mppages;
730 		pw->basenum += pw->mppages;
731 		pw->mp = pw->mp->ml_next;
732 		if (pw->mp != NULL) {
733 			pw->mppages = pw->mp->ml_size >> PAGESHIFT;
734 			pw->mpleft = pw->mppages;
735 			pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
736 		}
737 	}
738 	return (PFN_INVALID);
739 }
740 
741 static pgcnt_t
742 dump_pfn_to_bitnum(pfn_t pfn)
743 {
744 	struct memlist *mp;
745 	pgcnt_t bitnum = 0;
746 
747 	for (mp = phys_install; mp != NULL; mp = mp->ml_next) {
748 		if (pfn >= (mp->ml_address >> PAGESHIFT) &&
749 		    pfn < ((mp->ml_address + mp->ml_size) >> PAGESHIFT))
750 			return (bitnum + pfn - (mp->ml_address >> PAGESHIFT));
751 		bitnum += mp->ml_size >> PAGESHIFT;
752 	}
753 	return ((pgcnt_t)-1);
754 }
755 
756 /*
757  * Set/test bitmap for a CBUF_MAPSIZE range which includes pfn. The
758  * mapping of pfn to range index is imperfect because pfn and bitnum
759  * do not have the same phase. To make sure a CBUF_MAPSIZE range is
760  * covered, call this for both ends:
761  *	dump_set_used(base)
762  *	dump_set_used(base+CBUF_MAPNP-1)
763  *
764  * This is used during a panic dump to mark pages allocated by
765  * dumpsys_get_maxmem(). The macro IS_DUMP_PAGE(pp) is used by
766  * page_get_mnode_freelist() to make sure pages used by dump are never
767  * allocated.
768  */
769 #define	CBUF_MAPP2R(pfn)	((pfn) >> (CBUF_MAPSHIFT - PAGESHIFT))
770 
771 static void
772 dump_set_used(pfn_t pfn)
773 {
774 
775 	pgcnt_t bitnum, rbitnum;
776 
777 	bitnum = dump_pfn_to_bitnum(pfn);
778 	ASSERT(bitnum != (pgcnt_t)-1);
779 
780 	rbitnum = CBUF_MAPP2R(bitnum);
781 	ASSERT(rbitnum < dumpcfg.rbitmapsize);
782 
783 	BT_SET(dumpcfg.rbitmap, rbitnum);
784 }
785 
786 int
787 dump_test_used(pfn_t pfn)
788 {
789 	pgcnt_t bitnum, rbitnum;
790 
791 	bitnum = dump_pfn_to_bitnum(pfn);
792 	ASSERT(bitnum != (pgcnt_t)-1);
793 
794 	rbitnum = CBUF_MAPP2R(bitnum);
795 	ASSERT(rbitnum < dumpcfg.rbitmapsize);
796 
797 	return (BT_TEST(dumpcfg.rbitmap, rbitnum));
798 }
799 
800 /*
801  * dumpbzalloc and dumpbzfree are callbacks from the bzip2 library.
802  * dumpsys_get_maxmem() uses them for BZ2_bzCompressInit().
803  */
804 static void *
805 dumpbzalloc(void *opaque, int items, int size)
806 {
807 	size_t *sz;
808 	char *ret;
809 
810 	ASSERT(opaque != NULL);
811 	sz = opaque;
812 	ret = dumpcfg.maxvm + *sz;
813 	*sz += items * size;
814 	*sz = P2ROUNDUP(*sz, BZ2_BZALLOC_ALIGN);
815 	ASSERT(*sz <= dumpcfg.maxvmsize);
816 	return (ret);
817 }
818 
819 /*ARGSUSED*/
820 static void
821 dumpbzfree(void *opaque, void *addr)
822 {
823 }
824 
825 /*
826  * Perform additional checks on the page to see if we can really use
827  * it. The kernel (kas) pages are always set in the bitmap. However,
828  * boot memory pages (prom_ppages or P_BOOTPAGES) are not in the
829  * bitmap. So we check for them.
830  */
831 static inline int
832 dump_pfn_check(pfn_t pfn)
833 {
834 	page_t *pp = page_numtopp_nolock(pfn);
835 	if (pp == NULL || pp->p_pagenum != pfn ||
836 #if defined(__sparc)
837 	    pp->p_vnode == &promvp ||
838 #else
839 	    PP_ISBOOTPAGES(pp) ||
840 #endif
841 	    pp->p_toxic != 0)
842 		return (0);
843 	return (1);
844 }
845 
846 /*
847  * Check a range to see if all contained pages are available and
848  * return non-zero if the range can be used.
849  */
850 static inline int
851 dump_range_check(pgcnt_t start, pgcnt_t end, pfn_t pfn)
852 {
853 	for (; start < end; start++, pfn++) {
854 		if (BT_TEST(dumpcfg.bitmap, start))
855 			return (0);
856 		if (!dump_pfn_check(pfn))
857 			return (0);
858 	}
859 	return (1);
860 }
861 
862 /*
863  * dumpsys_get_maxmem() is called during panic. Find unused ranges
864  * and use them for buffers. If we find enough memory switch to
865  * parallel bzip2, otherwise use parallel lzjb.
866  *
867  * It searches the dump bitmap in 2 passes. The first time it looks
868  * for CBUF_MAPSIZE ranges. On the second pass it uses small pages.
869  */
870 static void
871 dumpsys_get_maxmem()
872 {
873 	dumpcfg_t *cfg = &dumpcfg;
874 	cbuf_t *endcp = &cfg->cbuf[cfg->ncbuf];
875 	helper_t *endhp = &cfg->helper[cfg->nhelper];
876 	pgcnt_t bitnum, end;
877 	size_t sz, endsz, bz2size;
878 	pfn_t pfn, off;
879 	cbuf_t *cp;
880 	helper_t *hp, *ohp;
881 	dumpmlw_t mlw;
882 	int k;
883 
884 	/*
885 	 * Setting dump_plat_mincpu to 0 at any time forces a serial
886 	 * dump.
887 	 */
888 	if (dump_plat_mincpu == 0) {
889 		cfg->clevel = 0;
890 		return;
891 	}
892 
893 	/*
894 	 * There may be no point in looking for spare memory. If
895 	 * dumping all memory, then none is spare. If doing a serial
896 	 * dump, then already have buffers.
897 	 */
898 	if (cfg->maxsize == 0 || cfg->clevel < DUMP_CLEVEL_LZJB ||
899 	    (dump_conflags & DUMP_ALL) != 0) {
900 		if (cfg->clevel > DUMP_CLEVEL_LZJB)
901 			cfg->clevel = DUMP_CLEVEL_LZJB;
902 		return;
903 	}
904 
905 	sz = 0;
906 	cfg->found4m = 0;
907 	cfg->foundsm = 0;
908 
909 	/* bitmap of ranges used to estimate which pfns are being used */
910 	bzero(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.rbitmapsize));
911 
912 	/* find ranges that are not being dumped to use for buffers */
913 	dump_init_memlist_walker(&mlw);
914 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
915 		dump_timeleft = dump_timeout;
916 		end = bitnum + CBUF_MAPNP;
917 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
918 		ASSERT(pfn != PFN_INVALID);
919 
920 		/* skip partial range at end of mem segment */
921 		if (mlw.mpleft < CBUF_MAPNP) {
922 			end = bitnum + mlw.mpleft;
923 			continue;
924 		}
925 
926 		/* skip non aligned pages */
927 		off = P2PHASE(pfn, CBUF_MAPNP);
928 		if (off != 0) {
929 			end -= off;
930 			continue;
931 		}
932 
933 		if (!dump_range_check(bitnum, end, pfn))
934 			continue;
935 
936 		ASSERT((sz + CBUF_MAPSIZE) <= cfg->maxvmsize);
937 		hat_devload(kas.a_hat, cfg->maxvm + sz, CBUF_MAPSIZE, pfn,
938 		    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
939 		sz += CBUF_MAPSIZE;
940 		cfg->found4m++;
941 
942 		/* set the bitmap for both ends to be sure to cover the range */
943 		dump_set_used(pfn);
944 		dump_set_used(pfn + CBUF_MAPNP - 1);
945 
946 		if (sz >= cfg->maxsize)
947 			goto foundmax;
948 	}
949 
950 	/* Add small pages if we can't find enough large pages. */
951 	dump_init_memlist_walker(&mlw);
952 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
953 		dump_timeleft = dump_timeout;
954 		end = bitnum + CBUF_MAPNP;
955 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
956 		ASSERT(pfn != PFN_INVALID);
957 
958 		/* Find any non-aligned pages at start and end of segment. */
959 		off = P2PHASE(pfn, CBUF_MAPNP);
960 		if (mlw.mpleft < CBUF_MAPNP) {
961 			end = bitnum + mlw.mpleft;
962 		} else if (off != 0) {
963 			end -= off;
964 		} else if (cfg->found4m && dump_test_used(pfn)) {
965 			continue;
966 		}
967 
968 		for (; bitnum < end; bitnum++, pfn++) {
969 			dump_timeleft = dump_timeout;
970 			if (BT_TEST(dumpcfg.bitmap, bitnum))
971 				continue;
972 			if (!dump_pfn_check(pfn))
973 				continue;
974 			ASSERT((sz + PAGESIZE) <= cfg->maxvmsize);
975 			hat_devload(kas.a_hat, cfg->maxvm + sz, PAGESIZE, pfn,
976 			    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
977 			sz += PAGESIZE;
978 			cfg->foundsm++;
979 			dump_set_used(pfn);
980 			if (sz >= cfg->maxsize)
981 				goto foundmax;
982 		}
983 	}
984 
985 	/* Fall back to lzjb if we did not get enough memory for bzip2. */
986 	endsz = (cfg->maxsize * cfg->threshold) / cfg->nhelper;
987 	if (sz < endsz) {
988 		cfg->clevel = DUMP_CLEVEL_LZJB;
989 	}
990 
991 	/* Allocate memory for as many helpers as we can. */
992 foundmax:
993 
994 	/* Byte offsets into memory found and mapped above */
995 	endsz = sz;
996 	sz = 0;
997 
998 	/* Set the size for bzip2 state. Only bzip2 needs it. */
999 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
1000 
1001 	/* Skip the preallocate output buffers. */
1002 	cp = &cfg->cbuf[MINCBUFS];
1003 
1004 	/* Use this to move memory up from the preallocated helpers. */
1005 	ohp = cfg->helper;
1006 
1007 	/* Loop over all helpers and allocate memory. */
1008 	for (hp = cfg->helper; hp < endhp; hp++) {
1009 
1010 		/* Skip preallocated helpers by checking hp->page. */
1011 		if (hp->page == NULL) {
1012 			if (cfg->clevel <= DUMP_CLEVEL_LZJB) {
1013 				/* lzjb needs 2 1-page buffers */
1014 				if ((sz + (2 * PAGESIZE)) > endsz)
1015 					break;
1016 				hp->page = cfg->maxvm + sz;
1017 				sz += PAGESIZE;
1018 				hp->lzbuf = cfg->maxvm + sz;
1019 				sz += PAGESIZE;
1020 
1021 			} else if (ohp->lzbuf != NULL) {
1022 				/* re-use the preallocted lzjb page for bzip2 */
1023 				hp->page = ohp->lzbuf;
1024 				ohp->lzbuf = NULL;
1025 				++ohp;
1026 
1027 			} else {
1028 				/* bzip2 needs a 1-page buffer */
1029 				if ((sz + PAGESIZE) > endsz)
1030 					break;
1031 				hp->page = cfg->maxvm + sz;
1032 				sz += PAGESIZE;
1033 			}
1034 		}
1035 
1036 		/*
1037 		 * Add output buffers per helper. The number of
1038 		 * buffers per helper is determined by the ratio of
1039 		 * ncbuf to nhelper.
1040 		 */
1041 		for (k = 0; cp < endcp && (sz + CBUF_SIZE) <= endsz &&
1042 		    k < NCBUF_PER_HELPER; k++) {
1043 			cp->state = CBUF_FREEBUF;
1044 			cp->size = CBUF_SIZE;
1045 			cp->buf = cfg->maxvm + sz;
1046 			sz += CBUF_SIZE;
1047 			++cp;
1048 		}
1049 
1050 		/*
1051 		 * bzip2 needs compression state. Use the dumpbzalloc
1052 		 * and dumpbzfree callbacks to allocate the memory.
1053 		 * bzip2 does allocation only at init time.
1054 		 */
1055 		if (cfg->clevel >= DUMP_CLEVEL_BZIP2) {
1056 			if ((sz + bz2size) > endsz) {
1057 				hp->page = NULL;
1058 				break;
1059 			} else {
1060 				hp->bzstream.opaque = &sz;
1061 				hp->bzstream.bzalloc = dumpbzalloc;
1062 				hp->bzstream.bzfree = dumpbzfree;
1063 				(void) BZ2_bzCompressInit(&hp->bzstream,
1064 				    dump_bzip2_level, 0, 0);
1065 				hp->bzstream.opaque = NULL;
1066 			}
1067 		}
1068 	}
1069 
1070 	/* Finish allocating output buffers */
1071 	for (; cp < endcp && (sz + CBUF_SIZE) <= endsz; cp++) {
1072 		cp->state = CBUF_FREEBUF;
1073 		cp->size = CBUF_SIZE;
1074 		cp->buf = cfg->maxvm + sz;
1075 		sz += CBUF_SIZE;
1076 	}
1077 
1078 	/* Enable IS_DUMP_PAGE macro, which checks for pages we took. */
1079 	if (cfg->found4m || cfg->foundsm)
1080 		dump_check_used = 1;
1081 
1082 	ASSERT(sz <= endsz);
1083 }
1084 
1085 static void
1086 dumphdr_init(void)
1087 {
1088 	pgcnt_t npages = 0;
1089 
1090 	ASSERT(MUTEX_HELD(&dump_lock));
1091 
1092 	if (dumphdr == NULL) {
1093 		dumphdr = kmem_zalloc(sizeof (dumphdr_t), KM_SLEEP);
1094 		dumphdr->dump_magic = DUMP_MAGIC;
1095 		dumphdr->dump_version = DUMP_VERSION;
1096 		dumphdr->dump_wordsize = DUMP_WORDSIZE;
1097 		dumphdr->dump_pageshift = PAGESHIFT;
1098 		dumphdr->dump_pagesize = PAGESIZE;
1099 		dumphdr->dump_utsname = utsname;
1100 		(void) strcpy(dumphdr->dump_platform, platform);
1101 		dumpbuf.size = dumpbuf_iosize(maxphys);
1102 		dumpbuf.start = kmem_alloc(dumpbuf.size, KM_SLEEP);
1103 		dumpbuf.end = dumpbuf.start + dumpbuf.size;
1104 		dumpcfg.pids = kmem_alloc(v.v_proc * sizeof (pid_t), KM_SLEEP);
1105 		dumpcfg.helpermap = kmem_zalloc(BT_SIZEOFMAP(NCPU), KM_SLEEP);
1106 		LOCK_INIT_HELD(&dumpcfg.helper_lock);
1107 		dump_stack_scratch = kmem_alloc(STACK_BUF_SIZE, KM_SLEEP);
1108 		(void) strncpy(dumphdr->dump_uuid, dump_get_uuid(),
1109 		    sizeof (dumphdr->dump_uuid));
1110 	}
1111 
1112 	npages = num_phys_pages();
1113 
1114 	if (dumpcfg.bitmapsize != npages) {
1115 		size_t rlen = CBUF_MAPP2R(P2ROUNDUP(npages, CBUF_MAPNP));
1116 		void *map = kmem_alloc(BT_SIZEOFMAP(npages), KM_SLEEP);
1117 		void *rmap = kmem_alloc(BT_SIZEOFMAP(rlen), KM_SLEEP);
1118 
1119 		if (dumpcfg.bitmap != NULL)
1120 			kmem_free(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.
1121 			    bitmapsize));
1122 		if (dumpcfg.rbitmap != NULL)
1123 			kmem_free(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.
1124 			    rbitmapsize));
1125 		dumpcfg.bitmap = map;
1126 		dumpcfg.bitmapsize = npages;
1127 		dumpcfg.rbitmap = rmap;
1128 		dumpcfg.rbitmapsize = rlen;
1129 	}
1130 }
1131 
1132 /*
1133  * Establish a new dump device.
1134  */
1135 int
1136 dumpinit(vnode_t *vp, char *name, int justchecking)
1137 {
1138 	vnode_t *cvp;
1139 	vattr_t vattr;
1140 	vnode_t *cdev_vp;
1141 	int error = 0;
1142 
1143 	ASSERT(MUTEX_HELD(&dump_lock));
1144 
1145 	dumphdr_init();
1146 
1147 	cvp = common_specvp(vp);
1148 	if (cvp == dumpvp)
1149 		return (0);
1150 
1151 	/*
1152 	 * Determine whether this is a plausible dump device.  We want either:
1153 	 * (1) a real device that's not mounted and has a cb_dump routine, or
1154 	 * (2) a swapfile on some filesystem that has a vop_dump routine.
1155 	 */
1156 	if ((error = VOP_OPEN(&cvp, FREAD | FWRITE, kcred, NULL)) != 0)
1157 		return (error);
1158 
1159 	vattr.va_mask = AT_SIZE | AT_TYPE | AT_RDEV;
1160 	if ((error = VOP_GETATTR(cvp, &vattr, 0, kcred, NULL)) == 0) {
1161 		if (vattr.va_type == VBLK || vattr.va_type == VCHR) {
1162 			if (devopsp[getmajor(vattr.va_rdev)]->
1163 			    devo_cb_ops->cb_dump == nodev)
1164 				error = ENOTSUP;
1165 			else if (vfs_devismounted(vattr.va_rdev))
1166 				error = EBUSY;
1167 			if (strcmp(ddi_driver_name(VTOS(cvp)->s_dip),
1168 			    ZFS_DRIVER) == 0 &&
1169 			    IS_SWAPVP(common_specvp(cvp)))
1170 					error = EBUSY;
1171 		} else {
1172 			if (vn_matchopval(cvp, VOPNAME_DUMP, fs_nosys) ||
1173 			    !IS_SWAPVP(cvp))
1174 				error = ENOTSUP;
1175 		}
1176 	}
1177 
1178 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE)
1179 		error = ENOSPC;
1180 
1181 	if (error || justchecking) {
1182 		(void) VOP_CLOSE(cvp, FREAD | FWRITE, 1, (offset_t)0,
1183 		    kcred, NULL);
1184 		return (error);
1185 	}
1186 
1187 	VN_HOLD(cvp);
1188 
1189 	if (dumpvp != NULL)
1190 		dumpfini();	/* unconfigure the old dump device */
1191 
1192 	dumpvp = cvp;
1193 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
1194 	dumppath = kmem_alloc(strlen(name) + 1, KM_SLEEP);
1195 	(void) strcpy(dumppath, name);
1196 	dumpbuf.iosize = 0;
1197 
1198 	/*
1199 	 * If the dump device is a block device, attempt to open up the
1200 	 * corresponding character device and determine its maximum transfer
1201 	 * size.  We use this information to potentially resize dumpbuf to a
1202 	 * larger and more optimal size for performing i/o to the dump device.
1203 	 */
1204 	if (cvp->v_type == VBLK &&
1205 	    (cdev_vp = makespecvp(VTOS(cvp)->s_dev, VCHR)) != NULL) {
1206 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1207 			size_t blk_size;
1208 			struct dk_cinfo dki;
1209 			struct dk_minfo minf;
1210 
1211 			if (VOP_IOCTL(cdev_vp, DKIOCGMEDIAINFO,
1212 			    (intptr_t)&minf, FKIOCTL, kcred, NULL, NULL)
1213 			    == 0 && minf.dki_lbsize != 0)
1214 				blk_size = minf.dki_lbsize;
1215 			else
1216 				blk_size = DEV_BSIZE;
1217 
1218 			if (VOP_IOCTL(cdev_vp, DKIOCINFO, (intptr_t)&dki,
1219 			    FKIOCTL, kcred, NULL, NULL) == 0) {
1220 				dumpbuf.iosize = dki.dki_maxtransfer * blk_size;
1221 				dumpbuf_resize();
1222 			}
1223 			/*
1224 			 * If we are working with a zvol then dumpify it
1225 			 * if it's not being used as swap.
1226 			 */
1227 			if (strcmp(dki.dki_dname, ZVOL_DRIVER) == 0) {
1228 				if (IS_SWAPVP(common_specvp(cvp)))
1229 					error = EBUSY;
1230 				else if ((error = VOP_IOCTL(cdev_vp,
1231 				    DKIOCDUMPINIT, NULL, FKIOCTL, kcred,
1232 				    NULL, NULL)) != 0)
1233 					dumpfini();
1234 			}
1235 
1236 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1237 			    kcred, NULL);
1238 		}
1239 
1240 		VN_RELE(cdev_vp);
1241 	}
1242 
1243 	cmn_err(CE_CONT, "?dump on %s size %llu MB\n", name, dumpvp_size >> 20);
1244 
1245 	dump_update_clevel();
1246 
1247 	return (error);
1248 }
1249 
1250 void
1251 dumpfini(void)
1252 {
1253 	vattr_t vattr;
1254 	boolean_t is_zfs = B_FALSE;
1255 	vnode_t *cdev_vp;
1256 	ASSERT(MUTEX_HELD(&dump_lock));
1257 
1258 	kmem_free(dumppath, strlen(dumppath) + 1);
1259 
1260 	/*
1261 	 * Determine if we are using zvols for our dump device
1262 	 */
1263 	vattr.va_mask = AT_RDEV;
1264 	if (VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL) == 0) {
1265 		is_zfs = (getmajor(vattr.va_rdev) ==
1266 		    ddi_name_to_major(ZFS_DRIVER)) ? B_TRUE : B_FALSE;
1267 	}
1268 
1269 	/*
1270 	 * If we have a zvol dump device then we call into zfs so
1271 	 * that it may have a chance to cleanup.
1272 	 */
1273 	if (is_zfs &&
1274 	    (cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR)) != NULL) {
1275 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1276 			(void) VOP_IOCTL(cdev_vp, DKIOCDUMPFINI, NULL, FKIOCTL,
1277 			    kcred, NULL, NULL);
1278 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1279 			    kcred, NULL);
1280 		}
1281 		VN_RELE(cdev_vp);
1282 	}
1283 
1284 	(void) VOP_CLOSE(dumpvp, FREAD | FWRITE, 1, (offset_t)0, kcred, NULL);
1285 
1286 	VN_RELE(dumpvp);
1287 
1288 	dumpvp = NULL;
1289 	dumpvp_size = 0;
1290 	dumppath = NULL;
1291 }
1292 
1293 static offset_t
1294 dumpvp_flush(void)
1295 {
1296 	size_t size = P2ROUNDUP(dumpbuf.cur - dumpbuf.start, PAGESIZE);
1297 	hrtime_t iotime;
1298 	int err;
1299 
1300 	if (dumpbuf.vp_off + size > dumpbuf.vp_limit) {
1301 		dump_ioerr = ENOSPC;
1302 		dumpbuf.vp_off = dumpbuf.vp_limit;
1303 	} else if (size != 0) {
1304 		iotime = gethrtime();
1305 		dumpsync.iowait += iotime - dumpsync.iowaitts;
1306 		if (panicstr)
1307 			err = VOP_DUMP(dumpvp, dumpbuf.start,
1308 			    lbtodb(dumpbuf.vp_off), btod(size), NULL);
1309 		else
1310 			err = vn_rdwr(UIO_WRITE, dumpbuf.cdev_vp != NULL ?
1311 			    dumpbuf.cdev_vp : dumpvp, dumpbuf.start, size,
1312 			    dumpbuf.vp_off, UIO_SYSSPACE, 0, dumpbuf.vp_limit,
1313 			    kcred, 0);
1314 		if (err && dump_ioerr == 0)
1315 			dump_ioerr = err;
1316 		dumpsync.iowaitts = gethrtime();
1317 		dumpsync.iotime += dumpsync.iowaitts - iotime;
1318 		dumpsync.nwrite += size;
1319 		dumpbuf.vp_off += size;
1320 	}
1321 	dumpbuf.cur = dumpbuf.start;
1322 	dump_timeleft = dump_timeout;
1323 	return (dumpbuf.vp_off);
1324 }
1325 
1326 /* maximize write speed by keeping seek offset aligned with size */
1327 void
1328 dumpvp_write(const void *va, size_t size)
1329 {
1330 	size_t len, off, sz;
1331 
1332 	while (size != 0) {
1333 		len = MIN(size, dumpbuf.end - dumpbuf.cur);
1334 		if (len == 0) {
1335 			off = P2PHASE(dumpbuf.vp_off, dumpbuf.size);
1336 			if (off == 0 || !ISP2(dumpbuf.size)) {
1337 				(void) dumpvp_flush();
1338 			} else {
1339 				sz = dumpbuf.size - off;
1340 				dumpbuf.cur = dumpbuf.start + sz;
1341 				(void) dumpvp_flush();
1342 				ovbcopy(dumpbuf.start + sz, dumpbuf.start, off);
1343 				dumpbuf.cur += off;
1344 			}
1345 		} else {
1346 			bcopy(va, dumpbuf.cur, len);
1347 			va = (char *)va + len;
1348 			dumpbuf.cur += len;
1349 			size -= len;
1350 		}
1351 	}
1352 }
1353 
1354 /*ARGSUSED*/
1355 static void
1356 dumpvp_ksyms_write(const void *src, void *dst, size_t size)
1357 {
1358 	dumpvp_write(src, size);
1359 }
1360 
1361 /*
1362  * Mark 'pfn' in the bitmap and dump its translation table entry.
1363  */
1364 void
1365 dump_addpage(struct as *as, void *va, pfn_t pfn)
1366 {
1367 	mem_vtop_t mem_vtop;
1368 	pgcnt_t bitnum;
1369 
1370 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1371 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1372 			dumphdr->dump_npages++;
1373 			BT_SET(dumpcfg.bitmap, bitnum);
1374 		}
1375 		dumphdr->dump_nvtop++;
1376 		mem_vtop.m_as = as;
1377 		mem_vtop.m_va = va;
1378 		mem_vtop.m_pfn = pfn;
1379 		dumpvp_write(&mem_vtop, sizeof (mem_vtop_t));
1380 	}
1381 	dump_timeleft = dump_timeout;
1382 }
1383 
1384 /*
1385  * Mark 'pfn' in the bitmap
1386  */
1387 void
1388 dump_page(pfn_t pfn)
1389 {
1390 	pgcnt_t bitnum;
1391 
1392 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1393 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1394 			dumphdr->dump_npages++;
1395 			BT_SET(dumpcfg.bitmap, bitnum);
1396 		}
1397 	}
1398 	dump_timeleft = dump_timeout;
1399 }
1400 
1401 /*
1402  * Dump the <as, va, pfn> information for a given address space.
1403  * SEGOP_DUMP() will call dump_addpage() for each page in the segment.
1404  */
1405 static void
1406 dump_as(struct as *as)
1407 {
1408 	struct seg *seg;
1409 
1410 	AS_LOCK_ENTER(as, &as->a_lock, RW_READER);
1411 	for (seg = AS_SEGFIRST(as); seg; seg = AS_SEGNEXT(as, seg)) {
1412 		if (seg->s_as != as)
1413 			break;
1414 		if (seg->s_ops == NULL)
1415 			continue;
1416 		SEGOP_DUMP(seg);
1417 	}
1418 	AS_LOCK_EXIT(as, &as->a_lock);
1419 
1420 	if (seg != NULL)
1421 		cmn_err(CE_WARN, "invalid segment %p in address space %p",
1422 		    (void *)seg, (void *)as);
1423 }
1424 
1425 static int
1426 dump_process(pid_t pid)
1427 {
1428 	proc_t *p = sprlock(pid);
1429 
1430 	if (p == NULL)
1431 		return (-1);
1432 	if (p->p_as != &kas) {
1433 		mutex_exit(&p->p_lock);
1434 		dump_as(p->p_as);
1435 		mutex_enter(&p->p_lock);
1436 	}
1437 
1438 	sprunlock(p);
1439 
1440 	return (0);
1441 }
1442 
1443 /*
1444  * The following functions (dump_summary(), dump_ereports(), and
1445  * dump_messages()), write data to an uncompressed area within the
1446  * crashdump. The layout of these is
1447  *
1448  * +------------------------------------------------------------+
1449  * |     compressed pages       | summary | ereports | messages |
1450  * +------------------------------------------------------------+
1451  *
1452  * With the advent of saving a compressed crash dump by default, we
1453  * need to save a little more data to describe the failure mode in
1454  * an uncompressed buffer available before savecore uncompresses
1455  * the dump. Initially this is a copy of the stack trace. Additional
1456  * summary information should be added here.
1457  */
1458 
1459 void
1460 dump_summary(void)
1461 {
1462 	u_offset_t dumpvp_start;
1463 	summary_dump_t sd;
1464 
1465 	if (dumpvp == NULL || dumphdr == NULL)
1466 		return;
1467 
1468 	dumpbuf.cur = dumpbuf.start;
1469 
1470 	dumpbuf.vp_limit = dumpvp_size - (DUMP_OFFSET + DUMP_LOGSIZE +
1471 	    DUMP_ERPTSIZE);
1472 	dumpvp_start = dumpbuf.vp_limit - DUMP_SUMMARYSIZE;
1473 	dumpbuf.vp_off = dumpvp_start;
1474 
1475 	sd.sd_magic = SUMMARY_MAGIC;
1476 	sd.sd_ssum = checksum32(dump_stack_scratch, STACK_BUF_SIZE);
1477 	dumpvp_write(&sd, sizeof (sd));
1478 	dumpvp_write(dump_stack_scratch, STACK_BUF_SIZE);
1479 
1480 	sd.sd_magic = 0; /* indicate end of summary */
1481 	dumpvp_write(&sd, sizeof (sd));
1482 	(void) dumpvp_flush();
1483 }
1484 
1485 void
1486 dump_ereports(void)
1487 {
1488 	u_offset_t dumpvp_start;
1489 	erpt_dump_t ed;
1490 
1491 	if (dumpvp == NULL || dumphdr == NULL)
1492 		return;
1493 
1494 	dumpbuf.cur = dumpbuf.start;
1495 	dumpbuf.vp_limit = dumpvp_size - (DUMP_OFFSET + DUMP_LOGSIZE);
1496 	dumpvp_start = dumpbuf.vp_limit - DUMP_ERPTSIZE;
1497 	dumpbuf.vp_off = dumpvp_start;
1498 
1499 	fm_ereport_dump();
1500 	if (panicstr)
1501 		errorq_dump();
1502 
1503 	bzero(&ed, sizeof (ed)); /* indicate end of ereports */
1504 	dumpvp_write(&ed, sizeof (ed));
1505 	(void) dumpvp_flush();
1506 
1507 	if (!panicstr) {
1508 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1509 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1510 		    B_INVAL | B_FORCE, kcred, NULL);
1511 	}
1512 }
1513 
1514 void
1515 dump_messages(void)
1516 {
1517 	log_dump_t ld;
1518 	mblk_t *mctl, *mdata;
1519 	queue_t *q, *qlast;
1520 	u_offset_t dumpvp_start;
1521 
1522 	if (dumpvp == NULL || dumphdr == NULL || log_consq == NULL)
1523 		return;
1524 
1525 	dumpbuf.cur = dumpbuf.start;
1526 	dumpbuf.vp_limit = dumpvp_size - DUMP_OFFSET;
1527 	dumpvp_start = dumpbuf.vp_limit - DUMP_LOGSIZE;
1528 	dumpbuf.vp_off = dumpvp_start;
1529 
1530 	qlast = NULL;
1531 	do {
1532 		for (q = log_consq; q->q_next != qlast; q = q->q_next)
1533 			continue;
1534 		for (mctl = q->q_first; mctl != NULL; mctl = mctl->b_next) {
1535 			dump_timeleft = dump_timeout;
1536 			mdata = mctl->b_cont;
1537 			ld.ld_magic = LOG_MAGIC;
1538 			ld.ld_msgsize = MBLKL(mctl->b_cont);
1539 			ld.ld_csum = checksum32(mctl->b_rptr, MBLKL(mctl));
1540 			ld.ld_msum = checksum32(mdata->b_rptr, MBLKL(mdata));
1541 			dumpvp_write(&ld, sizeof (ld));
1542 			dumpvp_write(mctl->b_rptr, MBLKL(mctl));
1543 			dumpvp_write(mdata->b_rptr, MBLKL(mdata));
1544 		}
1545 	} while ((qlast = q) != log_consq);
1546 
1547 	ld.ld_magic = 0;		/* indicate end of messages */
1548 	dumpvp_write(&ld, sizeof (ld));
1549 	(void) dumpvp_flush();
1550 	if (!panicstr) {
1551 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1552 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1553 		    B_INVAL | B_FORCE, kcred, NULL);
1554 	}
1555 }
1556 
1557 /*
1558  * The following functions are called on multiple CPUs during dump.
1559  * They must not use most kernel services, because all cross-calls are
1560  * disabled during panic. Therefore, blocking locks and cache flushes
1561  * will not work.
1562  */
1563 
1564 /*
1565  * Copy pages, trapping ECC errors. Also, for robustness, trap data
1566  * access in case something goes wrong in the hat layer and the
1567  * mapping is broken.
1568  */
1569 static int
1570 dump_pagecopy(void *src, void *dst)
1571 {
1572 	long *wsrc = (long *)src;
1573 	long *wdst = (long *)dst;
1574 	const ulong_t ncopies = PAGESIZE / sizeof (long);
1575 	volatile int w = 0;
1576 	volatile int ueoff = -1;
1577 	on_trap_data_t otd;
1578 
1579 	if (on_trap(&otd, OT_DATA_EC | OT_DATA_ACCESS)) {
1580 		if (ueoff == -1)
1581 			ueoff = w * sizeof (long);
1582 		/* report "bad ECC" or "bad address" */
1583 #ifdef _LP64
1584 		if (otd.ot_trap & OT_DATA_EC)
1585 			wdst[w++] = 0x00badecc00badecc;
1586 		else
1587 			wdst[w++] = 0x00badadd00badadd;
1588 #else
1589 		if (otd.ot_trap & OT_DATA_EC)
1590 			wdst[w++] = 0x00badecc;
1591 		else
1592 			wdst[w++] = 0x00badadd;
1593 #endif
1594 	}
1595 	while (w < ncopies) {
1596 		wdst[w] = wsrc[w];
1597 		w++;
1598 	}
1599 	no_trap();
1600 	return (ueoff);
1601 }
1602 
1603 static void
1604 dumpsys_close_cq(cqueue_t *cq, int live)
1605 {
1606 	if (live) {
1607 		mutex_enter(&cq->mutex);
1608 		atomic_dec_uint(&cq->open);
1609 		cv_signal(&cq->cv);
1610 		mutex_exit(&cq->mutex);
1611 	} else {
1612 		atomic_dec_uint(&cq->open);
1613 	}
1614 }
1615 
1616 static inline void
1617 dumpsys_spinlock(lock_t *lp)
1618 {
1619 	uint_t backoff = 0;
1620 	int loop_count = 0;
1621 
1622 	while (LOCK_HELD(lp) || !lock_spin_try(lp)) {
1623 		if (++loop_count >= ncpus) {
1624 			backoff = mutex_lock_backoff(0);
1625 			loop_count = 0;
1626 		} else {
1627 			backoff = mutex_lock_backoff(backoff);
1628 		}
1629 		mutex_lock_delay(backoff);
1630 	}
1631 }
1632 
1633 static inline void
1634 dumpsys_spinunlock(lock_t *lp)
1635 {
1636 	lock_clear(lp);
1637 }
1638 
1639 static inline void
1640 dumpsys_lock(cqueue_t *cq, int live)
1641 {
1642 	if (live)
1643 		mutex_enter(&cq->mutex);
1644 	else
1645 		dumpsys_spinlock(&cq->spinlock);
1646 }
1647 
1648 static inline void
1649 dumpsys_unlock(cqueue_t *cq, int live, int signal)
1650 {
1651 	if (live) {
1652 		if (signal)
1653 			cv_signal(&cq->cv);
1654 		mutex_exit(&cq->mutex);
1655 	} else {
1656 		dumpsys_spinunlock(&cq->spinlock);
1657 	}
1658 }
1659 
1660 static void
1661 dumpsys_wait_cq(cqueue_t *cq, int live)
1662 {
1663 	if (live) {
1664 		cv_wait(&cq->cv, &cq->mutex);
1665 	} else {
1666 		dumpsys_spinunlock(&cq->spinlock);
1667 		while (cq->open)
1668 			if (cq->first)
1669 				break;
1670 		dumpsys_spinlock(&cq->spinlock);
1671 	}
1672 }
1673 
1674 static void
1675 dumpsys_put_cq(cqueue_t *cq, cbuf_t *cp, int newstate, int live)
1676 {
1677 	if (cp == NULL)
1678 		return;
1679 
1680 	dumpsys_lock(cq, live);
1681 
1682 	if (cq->ts != 0) {
1683 		cq->empty += gethrtime() - cq->ts;
1684 		cq->ts = 0;
1685 	}
1686 
1687 	cp->state = newstate;
1688 	cp->next = NULL;
1689 	if (cq->last == NULL)
1690 		cq->first = cp;
1691 	else
1692 		cq->last->next = cp;
1693 	cq->last = cp;
1694 
1695 	dumpsys_unlock(cq, live, 1);
1696 }
1697 
1698 static cbuf_t *
1699 dumpsys_get_cq(cqueue_t *cq, int live)
1700 {
1701 	cbuf_t *cp;
1702 	hrtime_t now = gethrtime();
1703 
1704 	dumpsys_lock(cq, live);
1705 
1706 	/* CONSTCOND */
1707 	while (1) {
1708 		cp = (cbuf_t *)cq->first;
1709 		if (cp == NULL) {
1710 			if (cq->open == 0)
1711 				break;
1712 			dumpsys_wait_cq(cq, live);
1713 			continue;
1714 		}
1715 		cq->first = cp->next;
1716 		if (cq->first == NULL) {
1717 			cq->last = NULL;
1718 			cq->ts = now;
1719 		}
1720 		break;
1721 	}
1722 
1723 	dumpsys_unlock(cq, live, cq->first != NULL || cq->open == 0);
1724 	return (cp);
1725 }
1726 
1727 /*
1728  * Send an error message to the console. If the main task is running
1729  * just write the message via uprintf. If a helper is running the
1730  * message has to be put on a queue for the main task. Setting fmt to
1731  * NULL means flush the error message buffer. If fmt is not NULL, just
1732  * add the text to the existing buffer.
1733  */
1734 static void
1735 dumpsys_errmsg(helper_t *hp, const char *fmt, ...)
1736 {
1737 	dumpsync_t *ds = hp->ds;
1738 	cbuf_t *cp = hp->cperr;
1739 	va_list adx;
1740 
1741 	if (hp->helper == MAINHELPER) {
1742 		if (fmt != NULL) {
1743 			if (ds->neednl) {
1744 				uprintf("\n");
1745 				ds->neednl = 0;
1746 			}
1747 			va_start(adx, fmt);
1748 			vuprintf(fmt, adx);
1749 			va_end(adx);
1750 		}
1751 	} else if (fmt == NULL) {
1752 		if (cp != NULL) {
1753 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1754 			hp->cperr = NULL;
1755 		}
1756 	} else {
1757 		if (hp->cperr == NULL) {
1758 			cp = CQ_GET(freebufq);
1759 			hp->cperr = cp;
1760 			cp->used = 0;
1761 		}
1762 		va_start(adx, fmt);
1763 		cp->used += vsnprintf(cp->buf + cp->used, cp->size - cp->used,
1764 		    fmt, adx);
1765 		va_end(adx);
1766 		if ((cp->used + LOG_MSGSIZE) > cp->size) {
1767 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1768 			hp->cperr = NULL;
1769 		}
1770 	}
1771 }
1772 
1773 /*
1774  * Write an output buffer to the dump file. If the main task is
1775  * running just write the data. If a helper is running the output is
1776  * placed on a queue for the main task.
1777  */
1778 static void
1779 dumpsys_swrite(helper_t *hp, cbuf_t *cp, size_t used)
1780 {
1781 	dumpsync_t *ds = hp->ds;
1782 
1783 	if (hp->helper == MAINHELPER) {
1784 		HRSTART(ds->perpage, write);
1785 		dumpvp_write(cp->buf, used);
1786 		HRSTOP(ds->perpage, write);
1787 		CQ_PUT(freebufq, cp, CBUF_FREEBUF);
1788 	} else {
1789 		cp->used = used;
1790 		CQ_PUT(mainq, cp, CBUF_WRITE);
1791 	}
1792 }
1793 
1794 /*
1795  * Copy one page within the mapped range. The offset starts at 0 and
1796  * is relative to the first pfn. cp->buf + cp->off is the address of
1797  * the first pfn. If dump_pagecopy returns a UE offset, create an
1798  * error message.  Returns the offset to the next pfn in the range
1799  * selected by the bitmap.
1800  */
1801 static int
1802 dumpsys_copy_page(helper_t *hp, int offset)
1803 {
1804 	cbuf_t *cp = hp->cpin;
1805 	int ueoff;
1806 
1807 	ASSERT(cp->off + offset + PAGESIZE <= cp->size);
1808 	ASSERT(BT_TEST(dumpcfg.bitmap, cp->bitnum));
1809 
1810 	ueoff = dump_pagecopy(cp->buf + cp->off + offset, hp->page);
1811 
1812 	/* ueoff is the offset in the page to a UE error */
1813 	if (ueoff != -1) {
1814 		uint64_t pa = ptob(cp->pfn) + offset + ueoff;
1815 
1816 		dumpsys_errmsg(hp, "cpu %d: memory error at PA 0x%08x.%08x\n",
1817 		    CPU->cpu_id, (uint32_t)(pa >> 32), (uint32_t)pa);
1818 	}
1819 
1820 	/*
1821 	 * Advance bitnum and offset to the next input page for the
1822 	 * next call to this function.
1823 	 */
1824 	offset += PAGESIZE;
1825 	cp->bitnum++;
1826 	while (cp->off + offset < cp->size) {
1827 		if (BT_TEST(dumpcfg.bitmap, cp->bitnum))
1828 			break;
1829 		offset += PAGESIZE;
1830 		cp->bitnum++;
1831 	}
1832 
1833 	return (offset);
1834 }
1835 
1836 /*
1837  * Read the helper queue, and copy one mapped page. Return 0 when
1838  * done. Return 1 when a page has been copied into hp->page.
1839  */
1840 static int
1841 dumpsys_sread(helper_t *hp)
1842 {
1843 	dumpsync_t *ds = hp->ds;
1844 
1845 	/* CONSTCOND */
1846 	while (1) {
1847 
1848 		/* Find the next input buffer. */
1849 		if (hp->cpin == NULL) {
1850 			HRSTART(hp->perpage, inwait);
1851 
1852 			/* CONSTCOND */
1853 			while (1) {
1854 				hp->cpin = CQ_GET(helperq);
1855 				dump_timeleft = dump_timeout;
1856 
1857 				/*
1858 				 * NULL return means the helper queue
1859 				 * is closed and empty.
1860 				 */
1861 				if (hp->cpin == NULL)
1862 					break;
1863 
1864 				/* Have input, check for dump I/O error. */
1865 				if (!dump_ioerr)
1866 					break;
1867 
1868 				/*
1869 				 * If an I/O error occurs, stay in the
1870 				 * loop in order to empty the helper
1871 				 * queue. Return the buffers to the
1872 				 * main task to unmap and free it.
1873 				 */
1874 				hp->cpin->used = 0;
1875 				CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1876 			}
1877 			HRSTOP(hp->perpage, inwait);
1878 
1879 			/* Stop here when the helper queue is closed. */
1880 			if (hp->cpin == NULL)
1881 				break;
1882 
1883 			/* Set the offset=0 to get the first pfn. */
1884 			hp->in = 0;
1885 
1886 			/* Set the total processed to 0 */
1887 			hp->used = 0;
1888 		}
1889 
1890 		/* Process the next page. */
1891 		if (hp->used < hp->cpin->used) {
1892 
1893 			/*
1894 			 * Get the next page from the input buffer and
1895 			 * return a copy.
1896 			 */
1897 			ASSERT(hp->in != -1);
1898 			HRSTART(hp->perpage, copy);
1899 			hp->in = dumpsys_copy_page(hp, hp->in);
1900 			hp->used += PAGESIZE;
1901 			HRSTOP(hp->perpage, copy);
1902 			break;
1903 
1904 		} else {
1905 
1906 			/*
1907 			 * Done with the input. Flush the VM and
1908 			 * return the buffer to the main task.
1909 			 */
1910 			if (panicstr && hp->helper != MAINHELPER)
1911 				hat_flush_range(kas.a_hat,
1912 				    hp->cpin->buf, hp->cpin->size);
1913 			dumpsys_errmsg(hp, NULL);
1914 			CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1915 			hp->cpin = NULL;
1916 		}
1917 	}
1918 
1919 	return (hp->cpin != NULL);
1920 }
1921 
1922 /*
1923  * Compress size bytes starting at buf with bzip2
1924  * mode:
1925  *	BZ_RUN		add one more compressed page
1926  *	BZ_FINISH	no more input, flush the state
1927  */
1928 static void
1929 dumpsys_bzrun(helper_t *hp, void *buf, size_t size, int mode)
1930 {
1931 	dumpsync_t *ds = hp->ds;
1932 	const int CSIZE = sizeof (dumpcsize_t);
1933 	bz_stream *ps = &hp->bzstream;
1934 	int rc = 0;
1935 	uint32_t csize;
1936 	dumpcsize_t cs;
1937 
1938 	/* Set input pointers to new input page */
1939 	if (size > 0) {
1940 		ps->avail_in = size;
1941 		ps->next_in = buf;
1942 	}
1943 
1944 	/* CONSTCOND */
1945 	while (1) {
1946 
1947 		/* Quit when all input has been consumed */
1948 		if (ps->avail_in == 0 && mode == BZ_RUN)
1949 			break;
1950 
1951 		/* Get a new output buffer */
1952 		if (hp->cpout == NULL) {
1953 			HRSTART(hp->perpage, outwait);
1954 			hp->cpout = CQ_GET(freebufq);
1955 			HRSTOP(hp->perpage, outwait);
1956 			ps->avail_out = hp->cpout->size - CSIZE;
1957 			ps->next_out = hp->cpout->buf + CSIZE;
1958 		}
1959 
1960 		/* Compress input, or finalize */
1961 		HRSTART(hp->perpage, compress);
1962 		rc = BZ2_bzCompress(ps, mode);
1963 		HRSTOP(hp->perpage, compress);
1964 
1965 		/* Check for error */
1966 		if (mode == BZ_RUN && rc != BZ_RUN_OK) {
1967 			dumpsys_errmsg(hp, "%d: BZ_RUN error %s at page %lx\n",
1968 			    hp->helper, BZ2_bzErrorString(rc),
1969 			    hp->cpin->pagenum);
1970 			break;
1971 		}
1972 
1973 		/* Write the buffer if it is full, or we are flushing */
1974 		if (ps->avail_out == 0 || mode == BZ_FINISH) {
1975 			csize = hp->cpout->size - CSIZE - ps->avail_out;
1976 			cs = DUMP_SET_TAG(csize, hp->tag);
1977 			if (csize > 0) {
1978 				(void) memcpy(hp->cpout->buf, &cs, CSIZE);
1979 				dumpsys_swrite(hp, hp->cpout, csize + CSIZE);
1980 				hp->cpout = NULL;
1981 			}
1982 		}
1983 
1984 		/* Check for final complete */
1985 		if (mode == BZ_FINISH) {
1986 			if (rc == BZ_STREAM_END)
1987 				break;
1988 			if (rc != BZ_FINISH_OK) {
1989 				dumpsys_errmsg(hp, "%d: BZ_FINISH error %s\n",
1990 				    hp->helper, BZ2_bzErrorString(rc));
1991 				break;
1992 			}
1993 		}
1994 	}
1995 
1996 	/* Cleanup state and buffers */
1997 	if (mode == BZ_FINISH) {
1998 
1999 		/* Reset state so that it is re-usable. */
2000 		(void) BZ2_bzCompressReset(&hp->bzstream);
2001 
2002 		/* Give any unused outout buffer to the main task */
2003 		if (hp->cpout != NULL) {
2004 			hp->cpout->used = 0;
2005 			CQ_PUT(mainq, hp->cpout, CBUF_ERRMSG);
2006 			hp->cpout = NULL;
2007 		}
2008 	}
2009 }
2010 
2011 static void
2012 dumpsys_bz2compress(helper_t *hp)
2013 {
2014 	dumpsync_t *ds = hp->ds;
2015 	dumpstreamhdr_t sh;
2016 
2017 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
2018 	sh.stream_pagenum = (pgcnt_t)-1;
2019 	sh.stream_npages = 0;
2020 	hp->cpin = NULL;
2021 	hp->cpout = NULL;
2022 	hp->cperr = NULL;
2023 	hp->in = 0;
2024 	hp->out = 0;
2025 	hp->bzstream.avail_in = 0;
2026 
2027 	/* Bump reference to mainq while we are running */
2028 	CQ_OPEN(mainq);
2029 
2030 	/* Get one page at a time */
2031 	while (dumpsys_sread(hp)) {
2032 		if (sh.stream_pagenum != hp->cpin->pagenum) {
2033 			sh.stream_pagenum = hp->cpin->pagenum;
2034 			sh.stream_npages = btop(hp->cpin->used);
2035 			dumpsys_bzrun(hp, &sh, sizeof (sh), BZ_RUN);
2036 		}
2037 		dumpsys_bzrun(hp, hp->page, PAGESIZE, 0);
2038 	}
2039 
2040 	/* Done with input, flush any partial buffer */
2041 	if (sh.stream_pagenum != (pgcnt_t)-1) {
2042 		dumpsys_bzrun(hp, NULL, 0, BZ_FINISH);
2043 		dumpsys_errmsg(hp, NULL);
2044 	}
2045 
2046 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
2047 
2048 	/* Decrement main queue count, we are done */
2049 	CQ_CLOSE(mainq);
2050 }
2051 
2052 /*
2053  * Compress with lzjb
2054  * write stream block if full or size==0
2055  * if csize==0 write stream header, else write <csize, data>
2056  * size==0 is a call to flush a buffer
2057  * hp->cpout is the buffer we are flushing or filling
2058  * hp->out is the next index to fill data
2059  * osize is either csize+data, or the size of a stream header
2060  */
2061 static void
2062 dumpsys_lzjbrun(helper_t *hp, size_t csize, void *buf, size_t size)
2063 {
2064 	dumpsync_t *ds = hp->ds;
2065 	const int CSIZE = sizeof (dumpcsize_t);
2066 	dumpcsize_t cs;
2067 	size_t osize = csize > 0 ? CSIZE + size : size;
2068 
2069 	/* If flush, and there is no buffer, just return */
2070 	if (size == 0 && hp->cpout == NULL)
2071 		return;
2072 
2073 	/* If flush, or cpout is full, write it out */
2074 	if (size == 0 ||
2075 	    hp->cpout != NULL && hp->out + osize > hp->cpout->size) {
2076 
2077 		/* Set tag+size word at the front of the stream block. */
2078 		cs = DUMP_SET_TAG(hp->out - CSIZE, hp->tag);
2079 		(void) memcpy(hp->cpout->buf, &cs, CSIZE);
2080 
2081 		/* Write block to dump file. */
2082 		dumpsys_swrite(hp, hp->cpout, hp->out);
2083 
2084 		/* Clear pointer to indicate we need a new buffer */
2085 		hp->cpout = NULL;
2086 
2087 		/* flushing, we are done */
2088 		if (size == 0)
2089 			return;
2090 	}
2091 
2092 	/* Get an output buffer if we dont have one. */
2093 	if (hp->cpout == NULL) {
2094 		HRSTART(hp->perpage, outwait);
2095 		hp->cpout = CQ_GET(freebufq);
2096 		HRSTOP(hp->perpage, outwait);
2097 		hp->out = CSIZE;
2098 	}
2099 
2100 	/* Store csize word. This is the size of compressed data. */
2101 	if (csize > 0) {
2102 		cs = DUMP_SET_TAG(csize, 0);
2103 		(void) memcpy(hp->cpout->buf + hp->out, &cs, CSIZE);
2104 		hp->out += CSIZE;
2105 	}
2106 
2107 	/* Store the data. */
2108 	(void) memcpy(hp->cpout->buf + hp->out, buf, size);
2109 	hp->out += size;
2110 }
2111 
2112 static void
2113 dumpsys_lzjbcompress(helper_t *hp)
2114 {
2115 	dumpsync_t *ds = hp->ds;
2116 	size_t csize;
2117 	dumpstreamhdr_t sh;
2118 
2119 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
2120 	sh.stream_pagenum = (pfn_t)-1;
2121 	sh.stream_npages = 0;
2122 	hp->cpin = NULL;
2123 	hp->cpout = NULL;
2124 	hp->cperr = NULL;
2125 	hp->in = 0;
2126 	hp->out = 0;
2127 
2128 	/* Bump reference to mainq while we are running */
2129 	CQ_OPEN(mainq);
2130 
2131 	/* Get one page at a time */
2132 	while (dumpsys_sread(hp)) {
2133 
2134 		/* Create a stream header for each new input map */
2135 		if (sh.stream_pagenum != hp->cpin->pagenum) {
2136 			sh.stream_pagenum = hp->cpin->pagenum;
2137 			sh.stream_npages = btop(hp->cpin->used);
2138 			dumpsys_lzjbrun(hp, 0, &sh, sizeof (sh));
2139 		}
2140 
2141 		/* Compress one page */
2142 		HRSTART(hp->perpage, compress);
2143 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2144 		HRSTOP(hp->perpage, compress);
2145 
2146 		/* Add csize+data to output block */
2147 		ASSERT(csize > 0 && csize <= PAGESIZE);
2148 		dumpsys_lzjbrun(hp, csize, hp->lzbuf, csize);
2149 	}
2150 
2151 	/* Done with input, flush any partial buffer */
2152 	if (sh.stream_pagenum != (pfn_t)-1) {
2153 		dumpsys_lzjbrun(hp, 0, NULL, 0);
2154 		dumpsys_errmsg(hp, NULL);
2155 	}
2156 
2157 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
2158 
2159 	/* Decrement main queue count, we are done */
2160 	CQ_CLOSE(mainq);
2161 }
2162 
2163 /*
2164  * Dump helper called from panic_idle() to compress pages.  CPUs in
2165  * this path must not call most kernel services.
2166  *
2167  * During panic, all but one of the CPUs is idle. These CPUs are used
2168  * as helpers working in parallel to copy and compress memory
2169  * pages. During a panic, however, these processors cannot call any
2170  * kernel services. This is because mutexes become no-ops during
2171  * panic, and, cross-call interrupts are inhibited.  Therefore, during
2172  * panic dump the helper CPUs communicate with the panic CPU using
2173  * memory variables. All memory mapping and I/O is performed by the
2174  * panic CPU.
2175  *
2176  * At dump configuration time, helper_lock is set and helpers_wanted
2177  * is 0. dumpsys() decides whether to set helpers_wanted before
2178  * clearing helper_lock.
2179  *
2180  * At panic time, idle CPUs spin-wait on helper_lock, then alternately
2181  * take the lock and become a helper, or return.
2182  */
2183 void
2184 dumpsys_helper()
2185 {
2186 	dumpsys_spinlock(&dumpcfg.helper_lock);
2187 	if (dumpcfg.helpers_wanted) {
2188 		helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2189 
2190 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2191 			if (hp->helper == FREEHELPER) {
2192 				hp->helper = CPU->cpu_id;
2193 				BT_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2194 
2195 				dumpsys_spinunlock(&dumpcfg.helper_lock);
2196 
2197 				if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2198 					dumpsys_lzjbcompress(hp);
2199 				else
2200 					dumpsys_bz2compress(hp);
2201 
2202 				hp->helper = DONEHELPER;
2203 				return;
2204 			}
2205 		}
2206 
2207 		/* No more helpers are needed. */
2208 		dumpcfg.helpers_wanted = 0;
2209 
2210 	}
2211 	dumpsys_spinunlock(&dumpcfg.helper_lock);
2212 }
2213 
2214 /*
2215  * No-wait helper callable in spin loops.
2216  *
2217  * Do not wait for helper_lock. Just check helpers_wanted. The caller
2218  * may decide to continue. This is the "c)ontinue, s)ync, r)eset? s"
2219  * case.
2220  */
2221 void
2222 dumpsys_helper_nw()
2223 {
2224 	if (dumpcfg.helpers_wanted)
2225 		dumpsys_helper();
2226 }
2227 
2228 /*
2229  * Dump helper for live dumps.
2230  * These run as a system task.
2231  */
2232 static void
2233 dumpsys_live_helper(void *arg)
2234 {
2235 	helper_t *hp = arg;
2236 
2237 	BT_ATOMIC_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2238 	if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2239 		dumpsys_lzjbcompress(hp);
2240 	else
2241 		dumpsys_bz2compress(hp);
2242 }
2243 
2244 /*
2245  * Compress one page with lzjb (single threaded case)
2246  */
2247 static void
2248 dumpsys_lzjb_page(helper_t *hp, cbuf_t *cp)
2249 {
2250 	dumpsync_t *ds = hp->ds;
2251 	uint32_t csize;
2252 
2253 	hp->helper = MAINHELPER;
2254 	hp->in = 0;
2255 	hp->used = 0;
2256 	hp->cpin = cp;
2257 	while (hp->used < cp->used) {
2258 		HRSTART(hp->perpage, copy);
2259 		hp->in = dumpsys_copy_page(hp, hp->in);
2260 		hp->used += PAGESIZE;
2261 		HRSTOP(hp->perpage, copy);
2262 
2263 		HRSTART(hp->perpage, compress);
2264 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2265 		HRSTOP(hp->perpage, compress);
2266 
2267 		HRSTART(hp->perpage, write);
2268 		dumpvp_write(&csize, sizeof (csize));
2269 		dumpvp_write(hp->lzbuf, csize);
2270 		HRSTOP(hp->perpage, write);
2271 	}
2272 	CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
2273 	hp->cpin = NULL;
2274 }
2275 
2276 /*
2277  * Main task to dump pages. This is called on the dump CPU.
2278  */
2279 static void
2280 dumpsys_main_task(void *arg)
2281 {
2282 	dumpsync_t *ds = arg;
2283 	pgcnt_t pagenum = 0, bitnum = 0, hibitnum;
2284 	dumpmlw_t mlw;
2285 	cbuf_t *cp;
2286 	pgcnt_t baseoff, pfnoff;
2287 	pfn_t base, pfn;
2288 	int sec, i, dumpserial;
2289 
2290 	/*
2291 	 * Fall back to serial mode if there are no helpers.
2292 	 * dump_plat_mincpu can be set to 0 at any time.
2293 	 * dumpcfg.helpermap must contain at least one member.
2294 	 */
2295 	dumpserial = 1;
2296 
2297 	if (dump_plat_mincpu != 0 && dumpcfg.clevel != 0) {
2298 		for (i = 0; i < BT_BITOUL(NCPU); ++i) {
2299 			if (dumpcfg.helpermap[i] != 0) {
2300 				dumpserial = 0;
2301 				break;
2302 			}
2303 		}
2304 	}
2305 
2306 	if (dumpserial) {
2307 		dumpcfg.clevel = 0;
2308 		if (dumpcfg.helper[0].lzbuf == NULL)
2309 			dumpcfg.helper[0].lzbuf = dumpcfg.helper[1].page;
2310 	}
2311 
2312 	dump_init_memlist_walker(&mlw);
2313 
2314 	/* CONSTCOND */
2315 	while (1) {
2316 
2317 		if (ds->percent > ds->percent_done) {
2318 			ds->percent_done = ds->percent;
2319 			sec = (gethrtime() - ds->start) / 1000 / 1000 / 1000;
2320 			uprintf("^\r%2d:%02d %3d%% done",
2321 			    sec / 60, sec % 60, ds->percent);
2322 			ds->neednl = 1;
2323 		}
2324 
2325 		while (CQ_IS_EMPTY(mainq) && !CQ_IS_EMPTY(writerq)) {
2326 
2327 			/* the writerq never blocks */
2328 			cp = CQ_GET(writerq);
2329 			if (cp == NULL)
2330 				break;
2331 
2332 			dump_timeleft = dump_timeout;
2333 
2334 			HRSTART(ds->perpage, write);
2335 			dumpvp_write(cp->buf, cp->used);
2336 			HRSTOP(ds->perpage, write);
2337 
2338 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2339 		}
2340 
2341 		/*
2342 		 * Wait here for some buffers to process. Returns NULL
2343 		 * when all helpers have terminated and all buffers
2344 		 * have been processed.
2345 		 */
2346 		cp = CQ_GET(mainq);
2347 
2348 		if (cp == NULL) {
2349 
2350 			/* Drain the write queue. */
2351 			if (!CQ_IS_EMPTY(writerq))
2352 				continue;
2353 
2354 			/* Main task exits here. */
2355 			break;
2356 		}
2357 
2358 		dump_timeleft = dump_timeout;
2359 
2360 		switch (cp->state) {
2361 
2362 		case CBUF_FREEMAP:
2363 
2364 			/*
2365 			 * Note that we drop CBUF_FREEMAP buffers on
2366 			 * the floor (they will not be on any cqueue)
2367 			 * when we no longer need them.
2368 			 */
2369 			if (bitnum >= dumpcfg.bitmapsize)
2370 				break;
2371 
2372 			if (dump_ioerr) {
2373 				bitnum = dumpcfg.bitmapsize;
2374 				CQ_CLOSE(helperq);
2375 				break;
2376 			}
2377 
2378 			HRSTART(ds->perpage, bitmap);
2379 			for (; bitnum < dumpcfg.bitmapsize; bitnum++)
2380 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2381 					break;
2382 			HRSTOP(ds->perpage, bitmap);
2383 			dump_timeleft = dump_timeout;
2384 
2385 			if (bitnum >= dumpcfg.bitmapsize) {
2386 				CQ_CLOSE(helperq);
2387 				break;
2388 			}
2389 
2390 			/*
2391 			 * Try to map CBUF_MAPSIZE ranges. Can't
2392 			 * assume that memory segment size is a
2393 			 * multiple of CBUF_MAPSIZE. Can't assume that
2394 			 * the segment starts on a CBUF_MAPSIZE
2395 			 * boundary.
2396 			 */
2397 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2398 			ASSERT(pfn != PFN_INVALID);
2399 			ASSERT(bitnum + mlw.mpleft <= dumpcfg.bitmapsize);
2400 
2401 			base = P2ALIGN(pfn, CBUF_MAPNP);
2402 			if (base < mlw.mpaddr) {
2403 				base = mlw.mpaddr;
2404 				baseoff = P2PHASE(base, CBUF_MAPNP);
2405 			} else {
2406 				baseoff = 0;
2407 			}
2408 
2409 			pfnoff = pfn - base;
2410 			if (pfnoff + mlw.mpleft < CBUF_MAPNP) {
2411 				hibitnum = bitnum + mlw.mpleft;
2412 				cp->size = ptob(pfnoff + mlw.mpleft);
2413 			} else {
2414 				hibitnum = bitnum - pfnoff + CBUF_MAPNP -
2415 				    baseoff;
2416 				cp->size = CBUF_MAPSIZE - ptob(baseoff);
2417 			}
2418 
2419 			cp->pfn = pfn;
2420 			cp->bitnum = bitnum++;
2421 			cp->pagenum = pagenum++;
2422 			cp->off = ptob(pfnoff);
2423 
2424 			for (; bitnum < hibitnum; bitnum++)
2425 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2426 					pagenum++;
2427 
2428 			dump_timeleft = dump_timeout;
2429 			cp->used = ptob(pagenum - cp->pagenum);
2430 
2431 			HRSTART(ds->perpage, map);
2432 			hat_devload(kas.a_hat, cp->buf, cp->size, base,
2433 			    PROT_READ, HAT_LOAD_NOCONSIST);
2434 			HRSTOP(ds->perpage, map);
2435 
2436 			ds->pages_mapped += btop(cp->size);
2437 			ds->pages_used += pagenum - cp->pagenum;
2438 
2439 			CQ_OPEN(mainq);
2440 
2441 			/*
2442 			 * If there are no helpers the main task does
2443 			 * non-streams lzjb compress.
2444 			 */
2445 			if (dumpserial) {
2446 				dumpsys_lzjb_page(dumpcfg.helper, cp);
2447 				break;
2448 			}
2449 
2450 			/* pass mapped pages to a helper */
2451 			CQ_PUT(helperq, cp, CBUF_INREADY);
2452 
2453 			/* the last page was done */
2454 			if (bitnum >= dumpcfg.bitmapsize)
2455 				CQ_CLOSE(helperq);
2456 
2457 			break;
2458 
2459 		case CBUF_USEDMAP:
2460 
2461 			ds->npages += btop(cp->used);
2462 
2463 			HRSTART(ds->perpage, unmap);
2464 			hat_unload(kas.a_hat, cp->buf, cp->size, HAT_UNLOAD);
2465 			HRSTOP(ds->perpage, unmap);
2466 
2467 			if (bitnum < dumpcfg.bitmapsize)
2468 				CQ_PUT(mainq, cp, CBUF_FREEMAP);
2469 			CQ_CLOSE(mainq);
2470 
2471 			ASSERT(ds->npages <= dumphdr->dump_npages);
2472 			ds->percent = ds->npages * 100LL / dumphdr->dump_npages;
2473 			break;
2474 
2475 		case CBUF_WRITE:
2476 
2477 			CQ_PUT(writerq, cp, CBUF_WRITE);
2478 			break;
2479 
2480 		case CBUF_ERRMSG:
2481 
2482 			if (cp->used > 0) {
2483 				cp->buf[cp->size - 2] = '\n';
2484 				cp->buf[cp->size - 1] = '\0';
2485 				if (ds->neednl) {
2486 					uprintf("\n%s", cp->buf);
2487 					ds->neednl = 0;
2488 				} else {
2489 					uprintf("%s", cp->buf);
2490 				}
2491 				/* wait for console output */
2492 				drv_usecwait(200000);
2493 				dump_timeleft = dump_timeout;
2494 			}
2495 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2496 			break;
2497 
2498 		default:
2499 			uprintf("dump: unexpected buffer state %d, "
2500 			    "buffer will be lost\n", cp->state);
2501 			break;
2502 
2503 		} /* end switch */
2504 
2505 	} /* end while(1) */
2506 }
2507 
2508 #ifdef	COLLECT_METRICS
2509 size_t
2510 dumpsys_metrics(dumpsync_t *ds, char *buf, size_t size)
2511 {
2512 	dumpcfg_t *cfg = &dumpcfg;
2513 	int myid = CPU->cpu_seqid;
2514 	int i, compress_ratio;
2515 	int sec, iorate;
2516 	helper_t *hp, *hpend = &cfg->helper[cfg->nhelper];
2517 	char *e = buf + size;
2518 	char *p = buf;
2519 
2520 	sec = ds->elapsed / (1000 * 1000 * 1000ULL);
2521 	if (sec < 1)
2522 		sec = 1;
2523 
2524 	if (ds->iotime < 1)
2525 		ds->iotime = 1;
2526 	iorate = (ds->nwrite * 100000ULL) / ds->iotime;
2527 
2528 	compress_ratio = 100LL * ds->npages / btopr(ds->nwrite + 1);
2529 
2530 #define	P(...) (p += p < e ? snprintf(p, e - p, __VA_ARGS__) : 0)
2531 
2532 	P("Master cpu_seqid,%d\n", CPU->cpu_seqid);
2533 	P("Master cpu_id,%d\n", CPU->cpu_id);
2534 	P("dump_flags,0x%x\n", dumphdr->dump_flags);
2535 	P("dump_ioerr,%d\n", dump_ioerr);
2536 
2537 	P("Helpers:\n");
2538 	for (i = 0; i < ncpus; i++) {
2539 		if ((i & 15) == 0)
2540 			P(",,%03d,", i);
2541 		if (i == myid)
2542 			P("   M");
2543 		else if (BT_TEST(cfg->helpermap, i))
2544 			P("%4d", cpu_seq[i]->cpu_id);
2545 		else
2546 			P("   *");
2547 		if ((i & 15) == 15)
2548 			P("\n");
2549 	}
2550 
2551 	P("ncbuf_used,%d\n", cfg->ncbuf_used);
2552 	P("ncmap,%d\n", cfg->ncmap);
2553 
2554 	P("Found %ldM ranges,%ld\n", (CBUF_MAPSIZE / DUMP_1MB), cfg->found4m);
2555 	P("Found small pages,%ld\n", cfg->foundsm);
2556 
2557 	P("Compression level,%d\n", cfg->clevel);
2558 	P("Compression type,%s %s\n", cfg->clevel == 0 ? "serial" : "parallel",
2559 	    cfg->clevel >= DUMP_CLEVEL_BZIP2 ? "bzip2" : "lzjb");
2560 	P("Compression ratio,%d.%02d\n", compress_ratio / 100, compress_ratio %
2561 	    100);
2562 	P("nhelper_used,%d\n", cfg->nhelper_used);
2563 
2564 	P("Dump I/O rate MBS,%d.%02d\n", iorate / 100, iorate % 100);
2565 	P("..total bytes,%lld\n", (u_longlong_t)ds->nwrite);
2566 	P("..total nsec,%lld\n", (u_longlong_t)ds->iotime);
2567 	P("dumpbuf.iosize,%ld\n", dumpbuf.iosize);
2568 	P("dumpbuf.size,%ld\n", dumpbuf.size);
2569 
2570 	P("Dump pages/sec,%llu\n", (u_longlong_t)ds->npages / sec);
2571 	P("Dump pages,%llu\n", (u_longlong_t)ds->npages);
2572 	P("Dump time,%d\n", sec);
2573 
2574 	if (ds->pages_mapped > 0)
2575 		P("per-cent map utilization,%d\n", (int)((100 * ds->pages_used)
2576 		    / ds->pages_mapped));
2577 
2578 	P("\nPer-page metrics:\n");
2579 	if (ds->npages > 0) {
2580 		for (hp = cfg->helper; hp != hpend; hp++) {
2581 #define	PERPAGE(x)	ds->perpage.x += hp->perpage.x;
2582 			PERPAGES;
2583 #undef PERPAGE
2584 		}
2585 #define	PERPAGE(x) \
2586 		P("%s nsec/page,%d\n", #x, (int)(ds->perpage.x / ds->npages));
2587 		PERPAGES;
2588 #undef PERPAGE
2589 		P("freebufq.empty,%d\n", (int)(ds->freebufq.empty /
2590 		    ds->npages));
2591 		P("helperq.empty,%d\n", (int)(ds->helperq.empty /
2592 		    ds->npages));
2593 		P("writerq.empty,%d\n", (int)(ds->writerq.empty /
2594 		    ds->npages));
2595 		P("mainq.empty,%d\n", (int)(ds->mainq.empty / ds->npages));
2596 
2597 		P("I/O wait nsec/page,%llu\n", (u_longlong_t)(ds->iowait /
2598 		    ds->npages));
2599 	}
2600 #undef P
2601 	if (p < e)
2602 		bzero(p, e - p);
2603 	return (p - buf);
2604 }
2605 #endif	/* COLLECT_METRICS */
2606 
2607 /*
2608  * Dump the system.
2609  */
2610 void
2611 dumpsys(void)
2612 {
2613 	dumpsync_t *ds = &dumpsync;
2614 	taskq_t *livetaskq = NULL;
2615 	pfn_t pfn;
2616 	pgcnt_t bitnum;
2617 	proc_t *p;
2618 	helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2619 	cbuf_t *cp;
2620 	pid_t npids, pidx;
2621 	char *content;
2622 	char *buf;
2623 	size_t size;
2624 	int save_dump_clevel;
2625 	dumpmlw_t mlw;
2626 	dumpcsize_t datatag;
2627 	dumpdatahdr_t datahdr;
2628 
2629 	if (dumpvp == NULL || dumphdr == NULL) {
2630 		uprintf("skipping system dump - no dump device configured\n");
2631 		if (panicstr) {
2632 			dumpcfg.helpers_wanted = 0;
2633 			dumpsys_spinunlock(&dumpcfg.helper_lock);
2634 		}
2635 		return;
2636 	}
2637 	dumpbuf.cur = dumpbuf.start;
2638 
2639 	/* clear the sync variables */
2640 	ASSERT(dumpcfg.nhelper > 0);
2641 	bzero(ds, sizeof (*ds));
2642 	ds->dumpcpu = CPU->cpu_id;
2643 
2644 	/*
2645 	 * Calculate the starting block for dump.  If we're dumping on a
2646 	 * swap device, start 1/5 of the way in; otherwise, start at the
2647 	 * beginning.  And never use the first page -- it may be a disk label.
2648 	 */
2649 	if (dumpvp->v_flag & VISSWAP)
2650 		dumphdr->dump_start = P2ROUNDUP(dumpvp_size / 5, DUMP_OFFSET);
2651 	else
2652 		dumphdr->dump_start = DUMP_OFFSET;
2653 
2654 	dumphdr->dump_flags = DF_VALID | DF_COMPLETE | DF_LIVE | DF_COMPRESSED;
2655 	dumphdr->dump_crashtime = gethrestime_sec();
2656 	dumphdr->dump_npages = 0;
2657 	dumphdr->dump_nvtop = 0;
2658 	bzero(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.bitmapsize));
2659 	dump_timeleft = dump_timeout;
2660 
2661 	if (panicstr) {
2662 		dumphdr->dump_flags &= ~DF_LIVE;
2663 		(void) VOP_DUMPCTL(dumpvp, DUMP_FREE, NULL, NULL);
2664 		(void) VOP_DUMPCTL(dumpvp, DUMP_ALLOC, NULL, NULL);
2665 		(void) vsnprintf(dumphdr->dump_panicstring, DUMP_PANICSIZE,
2666 		    panicstr, panicargs);
2667 
2668 	}
2669 
2670 	if (dump_conflags & DUMP_ALL)
2671 		content = "all";
2672 	else if (dump_conflags & DUMP_CURPROC)
2673 		content = "kernel + curproc";
2674 	else
2675 		content = "kernel";
2676 	uprintf("dumping to %s, offset %lld, content: %s\n", dumppath,
2677 	    dumphdr->dump_start, content);
2678 
2679 	/* Make sure nodename is current */
2680 	bcopy(utsname.nodename, dumphdr->dump_utsname.nodename, SYS_NMLN);
2681 
2682 	/*
2683 	 * If this is a live dump, try to open a VCHR vnode for better
2684 	 * performance. We must take care to flush the buffer cache
2685 	 * first.
2686 	 */
2687 	if (!panicstr) {
2688 		vnode_t *cdev_vp, *cmn_cdev_vp;
2689 
2690 		ASSERT(dumpbuf.cdev_vp == NULL);
2691 		cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR);
2692 		if (cdev_vp != NULL) {
2693 			cmn_cdev_vp = common_specvp(cdev_vp);
2694 			if (VOP_OPEN(&cmn_cdev_vp, FREAD | FWRITE, kcred, NULL)
2695 			    == 0) {
2696 				if (vn_has_cached_data(dumpvp))
2697 					(void) pvn_vplist_dirty(dumpvp, 0, NULL,
2698 					    B_INVAL | B_TRUNC, kcred);
2699 				dumpbuf.cdev_vp = cmn_cdev_vp;
2700 			} else {
2701 				VN_RELE(cdev_vp);
2702 			}
2703 		}
2704 	}
2705 
2706 	/*
2707 	 * Store a hires timestamp so we can look it up during debugging.
2708 	 */
2709 	lbolt_debug_entry();
2710 
2711 	/*
2712 	 * Leave room for the message and ereport save areas and terminal dump
2713 	 * header.
2714 	 */
2715 	dumpbuf.vp_limit = dumpvp_size - DUMP_LOGSIZE - DUMP_OFFSET -
2716 	    DUMP_ERPTSIZE;
2717 
2718 	/*
2719 	 * Write out the symbol table.  It's no longer compressed,
2720 	 * so its 'size' and 'csize' are equal.
2721 	 */
2722 	dumpbuf.vp_off = dumphdr->dump_ksyms = dumphdr->dump_start + PAGESIZE;
2723 	dumphdr->dump_ksyms_size = dumphdr->dump_ksyms_csize =
2724 	    ksyms_snapshot(dumpvp_ksyms_write, NULL, LONG_MAX);
2725 
2726 	/*
2727 	 * Write out the translation map.
2728 	 */
2729 	dumphdr->dump_map = dumpvp_flush();
2730 	dump_as(&kas);
2731 	dumphdr->dump_nvtop += dump_plat_addr();
2732 
2733 	/*
2734 	 * call into hat, which may have unmapped pages that also need to
2735 	 * be in the dump
2736 	 */
2737 	hat_dump();
2738 
2739 	if (dump_conflags & DUMP_ALL) {
2740 		mutex_enter(&pidlock);
2741 
2742 		for (npids = 0, p = practive; p != NULL; p = p->p_next)
2743 			dumpcfg.pids[npids++] = p->p_pid;
2744 
2745 		mutex_exit(&pidlock);
2746 
2747 		for (pidx = 0; pidx < npids; pidx++)
2748 			(void) dump_process(dumpcfg.pids[pidx]);
2749 
2750 		dump_init_memlist_walker(&mlw);
2751 		for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2752 			dump_timeleft = dump_timeout;
2753 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2754 			/*
2755 			 * Some hypervisors do not have all pages available to
2756 			 * be accessed by the guest OS.  Check for page
2757 			 * accessibility.
2758 			 */
2759 			if (plat_hold_page(pfn, PLAT_HOLD_NO_LOCK, NULL) !=
2760 			    PLAT_HOLD_OK)
2761 				continue;
2762 			BT_SET(dumpcfg.bitmap, bitnum);
2763 		}
2764 		dumphdr->dump_npages = dumpcfg.bitmapsize;
2765 		dumphdr->dump_flags |= DF_ALL;
2766 
2767 	} else if (dump_conflags & DUMP_CURPROC) {
2768 		/*
2769 		 * Determine which pid is to be dumped.  If we're panicking, we
2770 		 * dump the process associated with panic_thread (if any).  If
2771 		 * this is a live dump, we dump the process associated with
2772 		 * curthread.
2773 		 */
2774 		npids = 0;
2775 		if (panicstr) {
2776 			if (panic_thread != NULL &&
2777 			    panic_thread->t_procp != NULL &&
2778 			    panic_thread->t_procp != &p0) {
2779 				dumpcfg.pids[npids++] =
2780 				    panic_thread->t_procp->p_pid;
2781 			}
2782 		} else {
2783 			dumpcfg.pids[npids++] = curthread->t_procp->p_pid;
2784 		}
2785 
2786 		if (npids && dump_process(dumpcfg.pids[0]) == 0)
2787 			dumphdr->dump_flags |= DF_CURPROC;
2788 		else
2789 			dumphdr->dump_flags |= DF_KERNEL;
2790 
2791 	} else {
2792 		dumphdr->dump_flags |= DF_KERNEL;
2793 	}
2794 
2795 	dumphdr->dump_hashmask = (1 << highbit(dumphdr->dump_nvtop - 1)) - 1;
2796 
2797 	/*
2798 	 * Write out the pfn table.
2799 	 */
2800 	dumphdr->dump_pfn = dumpvp_flush();
2801 	dump_init_memlist_walker(&mlw);
2802 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2803 		dump_timeleft = dump_timeout;
2804 		if (!BT_TEST(dumpcfg.bitmap, bitnum))
2805 			continue;
2806 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2807 		ASSERT(pfn != PFN_INVALID);
2808 		dumpvp_write(&pfn, sizeof (pfn_t));
2809 	}
2810 	dump_plat_pfn();
2811 
2812 	/*
2813 	 * Write out all the pages.
2814 	 * Map pages, copy them handling UEs, compress, and write them out.
2815 	 * Cooperate with any helpers running on CPUs in panic_idle().
2816 	 */
2817 	dumphdr->dump_data = dumpvp_flush();
2818 
2819 	bzero(dumpcfg.helpermap, BT_SIZEOFMAP(NCPU));
2820 	ds->live = dumpcfg.clevel > 0 &&
2821 	    (dumphdr->dump_flags & DF_LIVE) != 0;
2822 
2823 	save_dump_clevel = dumpcfg.clevel;
2824 	if (panicstr)
2825 		dumpsys_get_maxmem();
2826 	else if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2827 		dumpcfg.clevel = DUMP_CLEVEL_LZJB;
2828 
2829 	dumpcfg.nhelper_used = 0;
2830 	for (hp = dumpcfg.helper; hp != hpend; hp++) {
2831 		if (hp->page == NULL) {
2832 			hp->helper = DONEHELPER;
2833 			continue;
2834 		}
2835 		++dumpcfg.nhelper_used;
2836 		hp->helper = FREEHELPER;
2837 		hp->taskqid = NULL;
2838 		hp->ds = ds;
2839 		bzero(&hp->perpage, sizeof (hp->perpage));
2840 		if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2841 			(void) BZ2_bzCompressReset(&hp->bzstream);
2842 	}
2843 
2844 	CQ_OPEN(freebufq);
2845 	CQ_OPEN(helperq);
2846 
2847 	dumpcfg.ncbuf_used = 0;
2848 	for (cp = dumpcfg.cbuf; cp != &dumpcfg.cbuf[dumpcfg.ncbuf]; cp++) {
2849 		if (cp->buf != NULL) {
2850 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2851 			++dumpcfg.ncbuf_used;
2852 		}
2853 	}
2854 
2855 	for (cp = dumpcfg.cmap; cp != &dumpcfg.cmap[dumpcfg.ncmap]; cp++)
2856 		CQ_PUT(mainq, cp, CBUF_FREEMAP);
2857 
2858 	ds->start = gethrtime();
2859 	ds->iowaitts = ds->start;
2860 
2861 	/* start helpers */
2862 	if (ds->live) {
2863 		int n = dumpcfg.nhelper_used;
2864 		int pri = MINCLSYSPRI - 25;
2865 
2866 		livetaskq = taskq_create("LiveDump", n, pri, n, n,
2867 		    TASKQ_PREPOPULATE);
2868 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2869 			if (hp->page == NULL)
2870 				continue;
2871 			hp->helper = hp - dumpcfg.helper;
2872 			hp->taskqid = taskq_dispatch(livetaskq,
2873 			    dumpsys_live_helper, (void *)hp, TQ_NOSLEEP);
2874 		}
2875 
2876 	} else {
2877 		if (panicstr)
2878 			kmem_dump_begin();
2879 		dumpcfg.helpers_wanted = dumpcfg.clevel > 0;
2880 		dumpsys_spinunlock(&dumpcfg.helper_lock);
2881 	}
2882 
2883 	/* run main task */
2884 	dumpsys_main_task(ds);
2885 
2886 	ds->elapsed = gethrtime() - ds->start;
2887 	if (ds->elapsed < 1)
2888 		ds->elapsed = 1;
2889 
2890 	if (livetaskq != NULL)
2891 		taskq_destroy(livetaskq);
2892 
2893 	if (ds->neednl) {
2894 		uprintf("\n");
2895 		ds->neednl = 0;
2896 	}
2897 
2898 	/* record actual pages dumped */
2899 	dumphdr->dump_npages = ds->npages;
2900 
2901 	/* platform-specific data */
2902 	dumphdr->dump_npages += dump_plat_data(dumpcfg.cbuf[0].buf);
2903 
2904 	/* note any errors by clearing DF_COMPLETE */
2905 	if (dump_ioerr || ds->npages < dumphdr->dump_npages)
2906 		dumphdr->dump_flags &= ~DF_COMPLETE;
2907 
2908 	/* end of stream blocks */
2909 	datatag = 0;
2910 	dumpvp_write(&datatag, sizeof (datatag));
2911 
2912 	bzero(&datahdr, sizeof (datahdr));
2913 
2914 	/* buffer for metrics */
2915 	buf = dumpcfg.cbuf[0].buf;
2916 	size = MIN(dumpcfg.cbuf[0].size, DUMP_OFFSET - sizeof (dumphdr_t) -
2917 	    sizeof (dumpdatahdr_t));
2918 
2919 	/* finish the kmem intercepts, collect kmem verbose info */
2920 	if (panicstr) {
2921 		datahdr.dump_metrics = kmem_dump_finish(buf, size);
2922 		buf += datahdr.dump_metrics;
2923 		size -= datahdr.dump_metrics;
2924 	}
2925 
2926 	/* record in the header whether this is a fault-management panic */
2927 	if (panicstr)
2928 		dumphdr->dump_fm_panic = is_fm_panic();
2929 
2930 	/* compression info in data header */
2931 	datahdr.dump_datahdr_magic = DUMP_DATAHDR_MAGIC;
2932 	datahdr.dump_datahdr_version = DUMP_DATAHDR_VERSION;
2933 	datahdr.dump_maxcsize = CBUF_SIZE;
2934 	datahdr.dump_maxrange = CBUF_MAPSIZE / PAGESIZE;
2935 	datahdr.dump_nstreams = dumpcfg.nhelper_used;
2936 	datahdr.dump_clevel = dumpcfg.clevel;
2937 #ifdef COLLECT_METRICS
2938 	if (dump_metrics_on)
2939 		datahdr.dump_metrics += dumpsys_metrics(ds, buf, size);
2940 #endif
2941 	datahdr.dump_data_csize = dumpvp_flush() - dumphdr->dump_data;
2942 
2943 	/*
2944 	 * Write out the initial and terminal dump headers.
2945 	 */
2946 	dumpbuf.vp_off = dumphdr->dump_start;
2947 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
2948 	(void) dumpvp_flush();
2949 
2950 	dumpbuf.vp_limit = dumpvp_size;
2951 	dumpbuf.vp_off = dumpbuf.vp_limit - DUMP_OFFSET;
2952 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
2953 	dumpvp_write(&datahdr, sizeof (dumpdatahdr_t));
2954 	dumpvp_write(dumpcfg.cbuf[0].buf, datahdr.dump_metrics);
2955 
2956 	(void) dumpvp_flush();
2957 
2958 	uprintf("\r%3d%% done: %llu pages dumped, ",
2959 	    ds->percent_done, (u_longlong_t)ds->npages);
2960 
2961 	if (dump_ioerr == 0) {
2962 		uprintf("dump succeeded\n");
2963 	} else {
2964 		uprintf("dump failed: error %d\n", dump_ioerr);
2965 #ifdef DEBUG
2966 		if (panicstr)
2967 			debug_enter("dump failed");
2968 #endif
2969 	}
2970 
2971 	/*
2972 	 * Write out all undelivered messages.  This has to be the *last*
2973 	 * thing we do because the dump process itself emits messages.
2974 	 */
2975 	if (panicstr) {
2976 		dump_summary();
2977 		dump_ereports();
2978 		dump_messages();
2979 	}
2980 
2981 	delay(2 * hz);	/* let people see the 'done' message */
2982 	dump_timeleft = 0;
2983 	dump_ioerr = 0;
2984 
2985 	/* restore settings after live dump completes */
2986 	if (!panicstr) {
2987 		dumpcfg.clevel = save_dump_clevel;
2988 
2989 		/* release any VCHR open of the dump device */
2990 		if (dumpbuf.cdev_vp != NULL) {
2991 			(void) VOP_CLOSE(dumpbuf.cdev_vp, FREAD | FWRITE, 1, 0,
2992 			    kcred, NULL);
2993 			VN_RELE(dumpbuf.cdev_vp);
2994 			dumpbuf.cdev_vp = NULL;
2995 		}
2996 	}
2997 }
2998 
2999 /*
3000  * This function is called whenever the memory size, as represented
3001  * by the phys_install list, changes.
3002  */
3003 void
3004 dump_resize()
3005 {
3006 	mutex_enter(&dump_lock);
3007 	dumphdr_init();
3008 	dumpbuf_resize();
3009 	dump_update_clevel();
3010 	mutex_exit(&dump_lock);
3011 }
3012 
3013 /*
3014  * This function allows for dynamic resizing of a dump area. It assumes that
3015  * the underlying device has update its appropriate size(9P).
3016  */
3017 int
3018 dumpvp_resize()
3019 {
3020 	int error;
3021 	vattr_t vattr;
3022 
3023 	mutex_enter(&dump_lock);
3024 	vattr.va_mask = AT_SIZE;
3025 	if ((error = VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL)) != 0) {
3026 		mutex_exit(&dump_lock);
3027 		return (error);
3028 	}
3029 
3030 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE) {
3031 		mutex_exit(&dump_lock);
3032 		return (ENOSPC);
3033 	}
3034 
3035 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
3036 	mutex_exit(&dump_lock);
3037 	return (0);
3038 }
3039 
3040 int
3041 dump_set_uuid(const char *uuidstr)
3042 {
3043 	const char *ptr;
3044 	int i;
3045 
3046 	if (uuidstr == NULL || strnlen(uuidstr, 36 + 1) != 36)
3047 		return (EINVAL);
3048 
3049 	/* uuid_parse is not common code so check manually */
3050 	for (i = 0, ptr = uuidstr; i < 36; i++, ptr++) {
3051 		switch (i) {
3052 		case 8:
3053 		case 13:
3054 		case 18:
3055 		case 23:
3056 			if (*ptr != '-')
3057 				return (EINVAL);
3058 			break;
3059 
3060 		default:
3061 			if (!isxdigit(*ptr))
3062 				return (EINVAL);
3063 			break;
3064 		}
3065 	}
3066 
3067 	if (dump_osimage_uuid[0] != '\0')
3068 		return (EALREADY);
3069 
3070 	(void) strncpy(dump_osimage_uuid, uuidstr, 36 + 1);
3071 
3072 	cmn_err(CE_CONT, "?This Solaris instance has UUID %s\n",
3073 	    dump_osimage_uuid);
3074 
3075 	return (0);
3076 }
3077 
3078 const char *
3079 dump_get_uuid(void)
3080 {
3081 	return (dump_osimage_uuid[0] != '\0' ? dump_osimage_uuid : "");
3082 }
3083