xref: /titanic_41/usr/src/uts/common/os/dumpsubr.c (revision a2383ac57dcb38468bc1c213ee2d102d1e9038b1)
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 2010 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <sys/types.h>
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/vm.h>
31 #include <sys/proc.h>
32 #include <sys/file.h>
33 #include <sys/conf.h>
34 #include <sys/kmem.h>
35 #include <sys/mem.h>
36 #include <sys/mman.h>
37 #include <sys/vnode.h>
38 #include <sys/errno.h>
39 #include <sys/memlist.h>
40 #include <sys/dumphdr.h>
41 #include <sys/dumpadm.h>
42 #include <sys/ksyms.h>
43 #include <sys/compress.h>
44 #include <sys/stream.h>
45 #include <sys/strsun.h>
46 #include <sys/cmn_err.h>
47 #include <sys/bitmap.h>
48 #include <sys/modctl.h>
49 #include <sys/utsname.h>
50 #include <sys/systeminfo.h>
51 #include <sys/vmem.h>
52 #include <sys/log.h>
53 #include <sys/var.h>
54 #include <sys/debug.h>
55 #include <sys/sunddi.h>
56 #include <fs/fs_subr.h>
57 #include <sys/fs/snode.h>
58 #include <sys/ontrap.h>
59 #include <sys/panic.h>
60 #include <sys/dkio.h>
61 #include <sys/vtoc.h>
62 #include <sys/errorq.h>
63 #include <sys/fm/util.h>
64 #include <sys/fs/zfs.h>
65 
66 #include <vm/hat.h>
67 #include <vm/as.h>
68 #include <vm/page.h>
69 #include <vm/pvn.h>
70 #include <vm/seg.h>
71 #include <vm/seg_kmem.h>
72 #include <sys/clock_impl.h>
73 #include <sys/hold_page.h>
74 
75 #include <bzip2/bzlib.h>
76 
77 /*
78  * Crash dump time is dominated by disk write time.  To reduce this,
79  * the stronger compression method bzip2 is applied to reduce the dump
80  * size and hence reduce I/O time.  However, bzip2 is much more
81  * computationally expensive than the existing lzjb algorithm, so to
82  * avoid increasing compression time, CPUs that are otherwise idle
83  * during panic are employed to parallelize the compression task.
84  * Many helper CPUs are needed to prevent bzip2 from being a
85  * bottleneck, and on systems with too few CPUs, the lzjb algorithm is
86  * parallelized instead. Lastly, I/O and compression are performed by
87  * different CPUs, and are hence overlapped in time, unlike the older
88  * serial code.
89  *
90  * Another important consideration is the speed of the dump
91  * device. Faster disks need less CPUs in order to benefit from
92  * parallel lzjb versus parallel bzip2. Therefore, the CPU count
93  * threshold for switching from parallel lzjb to paralled bzip2 is
94  * elevated for faster disks. The dump device speed is adduced from
95  * the setting for dumpbuf.iosize, see dump_update_clevel.
96  */
97 
98 /*
99  * exported vars
100  */
101 kmutex_t	dump_lock;		/* lock for dump configuration */
102 dumphdr_t	*dumphdr;		/* dump header */
103 int		dump_conflags = DUMP_KERNEL; /* dump configuration flags */
104 vnode_t		*dumpvp;		/* dump device vnode pointer */
105 u_offset_t	dumpvp_size;		/* size of dump device, in bytes */
106 char		*dumppath;		/* pathname of dump device */
107 int		dump_timeout = 120;	/* timeout for dumping pages */
108 int		dump_timeleft;		/* portion of dump_timeout remaining */
109 int		dump_ioerr;		/* dump i/o error */
110 int		dump_check_used;	/* enable check for used pages */
111 
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 /* tunables for pre-reserved heap */
135 uint_t dump_kmem_permap = 1024;
136 uint_t dump_kmem_pages = 8;
137 
138 /* Define multiple buffers per helper to avoid stalling */
139 #define	NCBUF_PER_HELPER	2
140 #define	NCMAP_PER_HELPER	4
141 
142 /* minimum number of helpers configured */
143 #define	MINHELPERS	(dump_ncpu_low)
144 #define	MINCBUFS	(MINHELPERS * NCBUF_PER_HELPER)
145 
146 /*
147  * Define constant parameters.
148  *
149  * CBUF_SIZE		size of an output buffer
150  *
151  * CBUF_MAPSIZE		size of virtual range for mapping pages
152  *
153  * CBUF_MAPNP		size of virtual range in pages
154  *
155  */
156 #define	DUMP_1KB	((size_t)1 << 10)
157 #define	DUMP_1MB	((size_t)1 << 20)
158 #define	CBUF_SIZE	((size_t)1 << 17)
159 #define	CBUF_MAPSHIFT	(22)
160 #define	CBUF_MAPSIZE	((size_t)1 << CBUF_MAPSHIFT)
161 #define	CBUF_MAPNP	((size_t)1 << (CBUF_MAPSHIFT - PAGESHIFT))
162 
163 /*
164  * Compression metrics are accumulated nano-second subtotals. The
165  * results are normalized by the number of pages dumped. A report is
166  * generated when dumpsys() completes and is saved in the dump image
167  * after the trailing dump header.
168  *
169  * Metrics are always collected. Set the variable dump_metrics_on to
170  * cause metrics to be saved in the crash file, where savecore will
171  * save it in the file METRICS.txt.
172  */
173 #define	PERPAGES \
174 	PERPAGE(bitmap) PERPAGE(map) PERPAGE(unmap) \
175 	PERPAGE(copy) PERPAGE(compress) \
176 	PERPAGE(write) \
177 	PERPAGE(inwait) PERPAGE(outwait)
178 
179 typedef struct perpage {
180 #define	PERPAGE(x) hrtime_t x;
181 	PERPAGES
182 #undef PERPAGE
183 } perpage_t;
184 
185 /*
186  * This macro controls the code generation for collecting dump
187  * performance information. By default, the code is generated, but
188  * automatic saving of the information is disabled. If dump_metrics_on
189  * is set to 1, the timing information is passed to savecore via the
190  * crash file, where it is appended to the file dump-dir/METRICS.txt.
191  */
192 #define	COLLECT_METRICS
193 
194 #ifdef COLLECT_METRICS
195 uint_t dump_metrics_on = 0;	/* set to 1 to enable recording metrics */
196 
197 #define	HRSTART(v, m)		v##ts.m = gethrtime()
198 #define	HRSTOP(v, m)		v.m += gethrtime() - v##ts.m
199 #define	HRBEGIN(v, m, s)	v##ts.m = gethrtime(); v.size += s
200 #define	HREND(v, m)		v.m += gethrtime() - v##ts.m
201 #define	HRNORM(v, m, n)		v.m /= (n)
202 
203 #else
204 #define	HRSTART(v, m)
205 #define	HRSTOP(v, m)
206 #define	HRBEGIN(v, m, s)
207 #define	HREND(v, m)
208 #define	HRNORM(v, m, n)
209 #endif	/* COLLECT_METRICS */
210 
211 /*
212  * Buffers for copying and compressing memory pages.
213  *
214  * cbuf_t buffer controllers: used for both input and output.
215  *
216  * The buffer state indicates how it is being used:
217  *
218  * CBUF_FREEMAP: CBUF_MAPSIZE virtual address range is available for
219  * mapping input pages.
220  *
221  * CBUF_INREADY: input pages are mapped and ready for compression by a
222  * helper.
223  *
224  * CBUF_USEDMAP: mapping has been consumed by a helper. Needs unmap.
225  *
226  * CBUF_FREEBUF: CBUF_SIZE output buffer, which is available.
227  *
228  * CBUF_WRITE: CBUF_SIZE block of compressed pages from a helper,
229  * ready to write out.
230  *
231  * CBUF_ERRMSG: CBUF_SIZE block of error messages from a helper
232  * (reports UE errors.)
233  */
234 
235 typedef enum cbufstate {
236 	CBUF_FREEMAP,
237 	CBUF_INREADY,
238 	CBUF_USEDMAP,
239 	CBUF_FREEBUF,
240 	CBUF_WRITE,
241 	CBUF_ERRMSG
242 } cbufstate_t;
243 
244 typedef struct cbuf cbuf_t;
245 
246 struct cbuf {
247 	cbuf_t *next;			/* next in list */
248 	cbufstate_t state;		/* processing state */
249 	size_t used;			/* amount used */
250 	size_t size;			/* mem size */
251 	char *buf;			/* kmem or vmem */
252 	pgcnt_t pagenum;		/* index to pfn map */
253 	pgcnt_t bitnum;			/* first set bitnum */
254 	pfn_t pfn;			/* first pfn in mapped range */
255 	int off;			/* byte offset to first pfn */
256 };
257 
258 /*
259  * cqueue_t queues: a uni-directional channel for communication
260  * from the master to helper tasks or vice-versa using put and
261  * get primitives. Both mappings and data buffers are passed via
262  * queues. Producers close a queue when done. The number of
263  * active producers is reference counted so the consumer can
264  * detect end of data. Concurrent access is mediated by atomic
265  * operations for panic dump, or mutex/cv for live dump.
266  *
267  * There a four queues, used as follows:
268  *
269  * Queue		Dataflow		NewState
270  * --------------------------------------------------
271  * mainq		master -> master	FREEMAP
272  * master has initialized or unmapped an input buffer
273  * --------------------------------------------------
274  * helperq		master -> helper	INREADY
275  * master has mapped input for use by helper
276  * --------------------------------------------------
277  * mainq		master <- helper	USEDMAP
278  * helper is done with input
279  * --------------------------------------------------
280  * freebufq		master -> helper	FREEBUF
281  * master has initialized or written an output buffer
282  * --------------------------------------------------
283  * mainq		master <- helper	WRITE
284  * block of compressed pages from a helper
285  * --------------------------------------------------
286  * mainq		master <- helper	ERRMSG
287  * error messages from a helper (memory error case)
288  * --------------------------------------------------
289  * writerq		master <- master	WRITE
290  * non-blocking queue of blocks to write
291  * --------------------------------------------------
292  */
293 typedef struct cqueue {
294 	cbuf_t *volatile first;		/* first in list */
295 	cbuf_t *last;			/* last in list */
296 	hrtime_t ts;			/* timestamp */
297 	hrtime_t empty;			/* total time empty */
298 	kmutex_t mutex;			/* live state lock */
299 	kcondvar_t cv;			/* live wait var */
300 	lock_t spinlock;		/* panic mode spin lock */
301 	volatile uint_t open;		/* producer ref count */
302 } cqueue_t;
303 
304 /*
305  * Convenience macros for using the cqueue functions
306  * Note that the caller must have defined "dumpsync_t *ds"
307  */
308 #define	CQ_IS_EMPTY(q)					\
309 	(ds->q.first == NULL)
310 
311 #define	CQ_OPEN(q)					\
312 	atomic_inc_uint(&ds->q.open)
313 
314 #define	CQ_CLOSE(q)					\
315 	dumpsys_close_cq(&ds->q, ds->live)
316 
317 #define	CQ_PUT(q, cp, st)				\
318 	dumpsys_put_cq(&ds->q, cp, st, ds->live)
319 
320 #define	CQ_GET(q)					\
321 	dumpsys_get_cq(&ds->q, ds->live)
322 
323 /*
324  * Dynamic state when dumpsys() is running.
325  */
326 typedef struct dumpsync {
327 	pgcnt_t npages;			/* subtotal of pages dumped */
328 	pgcnt_t pages_mapped;		/* subtotal of pages mapped */
329 	pgcnt_t pages_used;		/* subtotal of pages used per map */
330 	size_t nwrite;			/* subtotal of bytes written */
331 	uint_t live;			/* running live dump */
332 	uint_t neednl;			/* will need to print a newline */
333 	uint_t percent;			/* dump progress */
334 	uint_t percent_done;		/* dump progress reported */
335 	cqueue_t freebufq;		/* free kmem bufs for writing */
336 	cqueue_t mainq;			/* input for main task */
337 	cqueue_t helperq;		/* input for helpers */
338 	cqueue_t writerq;		/* input for writer */
339 	hrtime_t start;			/* start time */
340 	hrtime_t elapsed;		/* elapsed time when completed */
341 	hrtime_t iotime;		/* time spent writing nwrite bytes */
342 	hrtime_t iowait;		/* time spent waiting for output */
343 	hrtime_t iowaitts;		/* iowait timestamp */
344 	perpage_t perpage;		/* metrics */
345 	perpage_t perpagets;
346 	int dumpcpu;			/* master cpu */
347 } dumpsync_t;
348 
349 static dumpsync_t dumpsync;		/* synchronization vars */
350 
351 /*
352  * helper_t helpers: contains the context for a stream. CPUs run in
353  * parallel at dump time; each CPU creates a single stream of
354  * compression data.  Stream data is divided into CBUF_SIZE blocks.
355  * The blocks are written in order within a stream. But, blocks from
356  * multiple streams can be interleaved. Each stream is identified by a
357  * unique tag.
358  */
359 typedef struct helper {
360 	int helper;			/* bound helper id */
361 	int tag;			/* compression stream tag */
362 	perpage_t perpage;		/* per page metrics */
363 	perpage_t perpagets;		/* per page metrics (timestamps) */
364 	taskqid_t taskqid;		/* live dump task ptr */
365 	int in, out;			/* buffer offsets */
366 	cbuf_t *cpin, *cpout, *cperr;	/* cbuf objects in process */
367 	dumpsync_t *ds;			/* pointer to sync vars */
368 	size_t used;			/* counts input consumed */
369 	char *page;			/* buffer for page copy */
370 	char *lzbuf;			/* lzjb output */
371 	bz_stream bzstream;		/* bzip2 state */
372 } helper_t;
373 
374 #define	MAINHELPER	(-1)		/* helper is also the main task */
375 #define	FREEHELPER	(-2)		/* unbound helper */
376 #define	DONEHELPER	(-3)		/* helper finished */
377 
378 /*
379  * configuration vars for dumpsys
380  */
381 typedef struct dumpcfg {
382 	int	threshold;	/* ncpu threshold for bzip2 */
383 	int	nhelper;	/* number of helpers */
384 	int	nhelper_used;	/* actual number of helpers used */
385 	int	ncmap;		/* number VA pages for compression */
386 	int	ncbuf;		/* number of bufs for compression */
387 	int	ncbuf_used;	/* number of bufs in use */
388 	uint_t	clevel;		/* dump compression level */
389 	helper_t *helper;	/* array of helpers */
390 	cbuf_t	*cmap;		/* array of input (map) buffers */
391 	cbuf_t	*cbuf;		/* array of output  buffers */
392 	ulong_t	*helpermap;	/* set of dumpsys helper CPU ids */
393 	ulong_t	*bitmap;	/* bitmap for marking pages to dump */
394 	ulong_t	*rbitmap;	/* bitmap for used CBUF_MAPSIZE ranges */
395 	pgcnt_t	bitmapsize;	/* size of bitmap */
396 	pgcnt_t	rbitmapsize;	/* size of bitmap for ranges */
397 	pgcnt_t found4m;	/* number ranges allocated by dump */
398 	pgcnt_t foundsm;	/* number small pages allocated by dump */
399 	pid_t	*pids;		/* list of process IDs at dump time */
400 	size_t	maxsize;	/* memory size needed at dump time */
401 	size_t	maxvmsize;	/* size of reserved VM */
402 	char	*maxvm;		/* reserved VM for spare pages */
403 	lock_t	helper_lock;	/* protect helper state */
404 	char	helpers_wanted;	/* flag to enable parallelism */
405 } dumpcfg_t;
406 
407 static dumpcfg_t dumpcfg;	/* config vars */
408 
409 /*
410  * The dump I/O buffer.
411  *
412  * There is one I/O buffer used by dumpvp_write and dumvp_flush. It is
413  * sized according to the optimum device transfer speed.
414  */
415 typedef struct dumpbuf {
416 	vnode_t	*cdev_vp;	/* VCHR open of the dump device */
417 	len_t	vp_limit;	/* maximum write offset */
418 	offset_t vp_off;	/* current dump device offset */
419 	char	*cur;		/* dump write pointer */
420 	char	*start;		/* dump buffer address */
421 	char	*end;		/* dump buffer end */
422 	size_t	size;		/* size of dumpbuf in bytes */
423 	size_t	iosize;		/* best transfer size for device */
424 } dumpbuf_t;
425 
426 dumpbuf_t dumpbuf;		/* I/O buffer */
427 
428 /*
429  * The dump I/O buffer must be at least one page, at most xfer_size
430  * bytes, and should scale with physmem in between.  The transfer size
431  * passed in will either represent a global default (maxphys) or the
432  * best size for the device.  The size of the dumpbuf I/O buffer is
433  * limited by dumpbuf_limit (8MB by default) because the dump
434  * performance saturates beyond a certain size.  The default is to
435  * select 1/4096 of the memory.
436  */
437 static int	dumpbuf_fraction = 12;	/* memory size scale factor */
438 static size_t	dumpbuf_limit = 8 * DUMP_1MB;	/* max I/O buf size */
439 
440 static size_t
441 dumpbuf_iosize(size_t xfer_size)
442 {
443 	size_t iosize = ptob(physmem >> dumpbuf_fraction);
444 
445 	if (iosize < PAGESIZE)
446 		iosize = PAGESIZE;
447 	else if (iosize > xfer_size)
448 		iosize = xfer_size;
449 	if (iosize > dumpbuf_limit)
450 		iosize = dumpbuf_limit;
451 	return (iosize & PAGEMASK);
452 }
453 
454 /*
455  * resize the I/O buffer
456  */
457 static void
458 dumpbuf_resize(void)
459 {
460 	char *old_buf = dumpbuf.start;
461 	size_t old_size = dumpbuf.size;
462 	char *new_buf;
463 	size_t new_size;
464 
465 	ASSERT(MUTEX_HELD(&dump_lock));
466 
467 	new_size = dumpbuf_iosize(MAX(dumpbuf.iosize, maxphys));
468 	if (new_size <= old_size)
469 		return; /* no need to reallocate buffer */
470 
471 	new_buf = kmem_alloc(new_size, KM_SLEEP);
472 	dumpbuf.size = new_size;
473 	dumpbuf.start = new_buf;
474 	dumpbuf.end = new_buf + new_size;
475 	kmem_free(old_buf, old_size);
476 }
477 
478 /*
479  * dump_update_clevel is called when dumpadm configures the dump device.
480  * 	Calculate number of helpers and buffers.
481  * 	Allocate the minimum configuration for now.
482  *
483  * When the dump file is configured we reserve a minimum amount of
484  * memory for use at crash time. But we reserve VA for all the memory
485  * we really want in order to do the fastest dump possible. The VA is
486  * backed by pages not being dumped, according to the bitmap. If
487  * there is insufficient spare memory, however, we fall back to the
488  * minimum.
489  *
490  * Live dump (savecore -L) always uses the minimum config.
491  *
492  * clevel 0 is single threaded lzjb
493  * clevel 1 is parallel lzjb
494  * clevel 2 is parallel bzip2
495  *
496  * The ncpu threshold is selected with dump_plat_mincpu.
497  * On OPL, set_platform_defaults() overrides the sun4u setting.
498  * The actual values are defined via DUMP_PLAT_*_MINCPU macros.
499  *
500  * Architecture		Threshold	Algorithm
501  * sun4u       		<  51		parallel lzjb
502  * sun4u       		>= 51		parallel bzip2(*)
503  * sun4u OPL   		<  8		parallel lzjb
504  * sun4u OPL   		>= 8		parallel bzip2(*)
505  * sun4v       		<  128		parallel lzjb
506  * sun4v       		>= 128		parallel bzip2(*)
507  * x86			< 11		parallel lzjb
508  * x86			>= 11		parallel bzip2(*)
509  * 32-bit      		N/A		single-threaded lzjb
510  *
511  * (*) bzip2 is only chosen if there is sufficient available
512  * memory for buffers at dump time. See dumpsys_get_maxmem().
513  *
514  * Faster dump devices have larger I/O buffers. The threshold value is
515  * increased according to the size of the dump I/O buffer, because
516  * parallel lzjb performs better with faster disks. For buffers >= 1MB
517  * the threshold is 3X; for buffers >= 256K threshold is 2X.
518  *
519  * For parallel dumps, the number of helpers is ncpu-1. The CPU
520  * running panic runs the main task. For single-threaded dumps, the
521  * panic CPU does lzjb compression (it is tagged as MAINHELPER.)
522  *
523  * Need multiple buffers per helper so that they do not block waiting
524  * for the main task.
525  *				parallel	single-threaded
526  * Number of output buffers:	nhelper*2		1
527  * Number of mapping buffers:	nhelper*4		1
528  *
529  */
530 static void
531 dump_update_clevel()
532 {
533 	int tag;
534 	size_t bz2size;
535 	helper_t *hp, *hpend;
536 	cbuf_t *cp, *cpend;
537 	dumpcfg_t *old = &dumpcfg;
538 	dumpcfg_t newcfg = *old;
539 	dumpcfg_t *new = &newcfg;
540 
541 	ASSERT(MUTEX_HELD(&dump_lock));
542 
543 	/*
544 	 * Free the previously allocated bufs and VM.
545 	 */
546 	if (old->helper != NULL) {
547 
548 		/* helpers */
549 		hpend = &old->helper[old->nhelper];
550 		for (hp = old->helper; hp != hpend; hp++) {
551 			if (hp->lzbuf != NULL)
552 				kmem_free(hp->lzbuf, PAGESIZE);
553 			if (hp->page != NULL)
554 				kmem_free(hp->page, PAGESIZE);
555 		}
556 		kmem_free(old->helper, old->nhelper * sizeof (helper_t));
557 
558 		/* VM space for mapping pages */
559 		cpend = &old->cmap[old->ncmap];
560 		for (cp = old->cmap; cp != cpend; cp++)
561 			vmem_xfree(heap_arena, cp->buf, CBUF_MAPSIZE);
562 		kmem_free(old->cmap, old->ncmap * sizeof (cbuf_t));
563 
564 		/* output bufs */
565 		cpend = &old->cbuf[old->ncbuf];
566 		for (cp = old->cbuf; cp != cpend; cp++)
567 			if (cp->buf != NULL)
568 				kmem_free(cp->buf, cp->size);
569 		kmem_free(old->cbuf, old->ncbuf * sizeof (cbuf_t));
570 
571 		/* reserved VM for dumpsys_get_maxmem */
572 		if (old->maxvmsize > 0)
573 			vmem_xfree(heap_arena, old->maxvm, old->maxvmsize);
574 	}
575 
576 	/*
577 	 * Allocate memory and VM.
578 	 * One CPU runs dumpsys, the rest are helpers.
579 	 */
580 	new->nhelper = ncpus - 1;
581 	if (new->nhelper < 1)
582 		new->nhelper = 1;
583 
584 	if (new->nhelper > DUMP_MAX_NHELPER)
585 		new->nhelper = DUMP_MAX_NHELPER;
586 
587 	/* increase threshold for faster disks */
588 	new->threshold = dump_plat_mincpu;
589 	if (dumpbuf.iosize >= DUMP_1MB)
590 		new->threshold *= 3;
591 	else if (dumpbuf.iosize >= (256 * DUMP_1KB))
592 		new->threshold *= 2;
593 
594 	/* figure compression level based upon the computed threshold. */
595 	if (dump_plat_mincpu == 0 || new->nhelper < 2) {
596 		new->clevel = 0;
597 		new->nhelper = 1;
598 	} else if ((new->nhelper + 1) >= new->threshold) {
599 		new->clevel = DUMP_CLEVEL_BZIP2;
600 	} else {
601 		new->clevel = DUMP_CLEVEL_LZJB;
602 	}
603 
604 	if (new->clevel == 0) {
605 		new->ncbuf = 1;
606 		new->ncmap = 1;
607 	} else {
608 		new->ncbuf = NCBUF_PER_HELPER * new->nhelper;
609 		new->ncmap = NCMAP_PER_HELPER * new->nhelper;
610 	}
611 
612 	/*
613 	 * Allocate new data structures and buffers for MINHELPERS,
614 	 * and also figure the max desired size.
615 	 */
616 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
617 	new->maxsize = 0;
618 	new->maxvmsize = 0;
619 	new->maxvm = NULL;
620 	tag = 1;
621 	new->helper = kmem_zalloc(new->nhelper * sizeof (helper_t), KM_SLEEP);
622 	hpend = &new->helper[new->nhelper];
623 	for (hp = new->helper; hp != hpend; hp++) {
624 		hp->tag = tag++;
625 		if (hp < &new->helper[MINHELPERS]) {
626 			hp->lzbuf = kmem_alloc(PAGESIZE, KM_SLEEP);
627 			hp->page = kmem_alloc(PAGESIZE, KM_SLEEP);
628 		} else if (new->clevel < DUMP_CLEVEL_BZIP2) {
629 			new->maxsize += 2 * PAGESIZE;
630 		} else {
631 			new->maxsize += PAGESIZE;
632 		}
633 		if (new->clevel >= DUMP_CLEVEL_BZIP2)
634 			new->maxsize += bz2size;
635 	}
636 
637 	new->cbuf = kmem_zalloc(new->ncbuf * sizeof (cbuf_t), KM_SLEEP);
638 	cpend = &new->cbuf[new->ncbuf];
639 	for (cp = new->cbuf; cp != cpend; cp++) {
640 		cp->state = CBUF_FREEBUF;
641 		cp->size = CBUF_SIZE;
642 		if (cp < &new->cbuf[MINCBUFS])
643 			cp->buf = kmem_alloc(cp->size, KM_SLEEP);
644 		else
645 			new->maxsize += cp->size;
646 	}
647 
648 	new->cmap = kmem_zalloc(new->ncmap * sizeof (cbuf_t), KM_SLEEP);
649 	cpend = &new->cmap[new->ncmap];
650 	for (cp = new->cmap; cp != cpend; cp++) {
651 		cp->state = CBUF_FREEMAP;
652 		cp->size = CBUF_MAPSIZE;
653 		cp->buf = vmem_xalloc(heap_arena, CBUF_MAPSIZE, CBUF_MAPSIZE,
654 		    0, 0, NULL, NULL, VM_SLEEP);
655 	}
656 
657 	/* reserve VA to be backed with spare pages at crash time */
658 	if (new->maxsize > 0) {
659 		new->maxsize = P2ROUNDUP(new->maxsize, PAGESIZE);
660 		new->maxvmsize = P2ROUNDUP(new->maxsize, CBUF_MAPSIZE);
661 		new->maxvm = vmem_xalloc(heap_arena, new->maxvmsize,
662 		    CBUF_MAPSIZE, 0, 0, NULL, NULL, VM_SLEEP);
663 	}
664 
665 	/*
666 	 * Reserve memory for kmem allocation calls made during crash
667 	 * dump.  The hat layer allocates memory for each mapping
668 	 * created, and the I/O path allocates buffers and data structs.
669 	 * Add a few pages for safety.
670 	 */
671 	kmem_dump_init((new->ncmap * dump_kmem_permap) +
672 	    (dump_kmem_pages * PAGESIZE));
673 
674 	/* set new config pointers */
675 	*old = *new;
676 }
677 
678 /*
679  * Define a struct memlist walker to optimize bitnum to pfn
680  * lookup. The walker maintains the state of the list traversal.
681  */
682 typedef struct dumpmlw {
683 	struct memlist	*mp;		/* current memlist */
684 	pgcnt_t		basenum;	/* bitnum base offset */
685 	pgcnt_t		mppages;	/* current memlist size */
686 	pgcnt_t		mpleft;		/* size to end of current memlist */
687 	pfn_t		mpaddr;		/* first pfn in memlist */
688 } dumpmlw_t;
689 
690 /* initialize the walker */
691 static inline void
692 dump_init_memlist_walker(dumpmlw_t *pw)
693 {
694 	pw->mp = phys_install;
695 	pw->basenum = 0;
696 	pw->mppages = pw->mp->ml_size >> PAGESHIFT;
697 	pw->mpleft = pw->mppages;
698 	pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
699 }
700 
701 /*
702  * Lookup pfn given bitnum. The memlist can be quite long on some
703  * systems (e.g.: one per board). To optimize sequential lookups, the
704  * caller initializes and presents a memlist walker.
705  */
706 static pfn_t
707 dump_bitnum_to_pfn(pgcnt_t bitnum, dumpmlw_t *pw)
708 {
709 	bitnum -= pw->basenum;
710 	while (pw->mp != NULL) {
711 		if (bitnum < pw->mppages) {
712 			pw->mpleft = pw->mppages - bitnum;
713 			return (pw->mpaddr + bitnum);
714 		}
715 		bitnum -= pw->mppages;
716 		pw->basenum += pw->mppages;
717 		pw->mp = pw->mp->ml_next;
718 		if (pw->mp != NULL) {
719 			pw->mppages = pw->mp->ml_size >> PAGESHIFT;
720 			pw->mpleft = pw->mppages;
721 			pw->mpaddr = pw->mp->ml_address >> PAGESHIFT;
722 		}
723 	}
724 	return (PFN_INVALID);
725 }
726 
727 static pgcnt_t
728 dump_pfn_to_bitnum(pfn_t pfn)
729 {
730 	struct memlist *mp;
731 	pgcnt_t bitnum = 0;
732 
733 	for (mp = phys_install; mp != NULL; mp = mp->ml_next) {
734 		if (pfn >= (mp->ml_address >> PAGESHIFT) &&
735 		    pfn < ((mp->ml_address + mp->ml_size) >> PAGESHIFT))
736 			return (bitnum + pfn - (mp->ml_address >> PAGESHIFT));
737 		bitnum += mp->ml_size >> PAGESHIFT;
738 	}
739 	return ((pgcnt_t)-1);
740 }
741 
742 /*
743  * Set/test bitmap for a CBUF_MAPSIZE range which includes pfn. The
744  * mapping of pfn to range index is imperfect because pfn and bitnum
745  * do not have the same phase. To make sure a CBUF_MAPSIZE range is
746  * covered, call this for both ends:
747  *	dump_set_used(base)
748  *	dump_set_used(base+CBUF_MAPNP-1)
749  *
750  * This is used during a panic dump to mark pages allocated by
751  * dumpsys_get_maxmem(). The macro IS_DUMP_PAGE(pp) is used by
752  * page_get_mnode_freelist() to make sure pages used by dump are never
753  * allocated.
754  */
755 #define	CBUF_MAPP2R(pfn)	((pfn) >> (CBUF_MAPSHIFT - PAGESHIFT))
756 
757 static void
758 dump_set_used(pfn_t pfn)
759 {
760 
761 	pgcnt_t bitnum, rbitnum;
762 
763 	bitnum = dump_pfn_to_bitnum(pfn);
764 	ASSERT(bitnum != (pgcnt_t)-1);
765 
766 	rbitnum = CBUF_MAPP2R(bitnum);
767 	ASSERT(rbitnum < dumpcfg.rbitmapsize);
768 
769 	BT_SET(dumpcfg.rbitmap, rbitnum);
770 }
771 
772 int
773 dump_test_used(pfn_t pfn)
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 	return (BT_TEST(dumpcfg.rbitmap, rbitnum));
784 }
785 
786 /*
787  * dumpbzalloc and dumpbzfree are callbacks from the bzip2 library.
788  * dumpsys_get_maxmem() uses them for BZ2_bzCompressInit().
789  */
790 static void *
791 dumpbzalloc(void *opaque, int items, int size)
792 {
793 	size_t *sz;
794 	char *ret;
795 
796 	ASSERT(opaque != NULL);
797 	sz = opaque;
798 	ret = dumpcfg.maxvm + *sz;
799 	*sz += items * size;
800 	*sz = P2ROUNDUP(*sz, BZ2_BZALLOC_ALIGN);
801 	ASSERT(*sz <= dumpcfg.maxvmsize);
802 	return (ret);
803 }
804 
805 /*ARGSUSED*/
806 static void
807 dumpbzfree(void *opaque, void *addr)
808 {
809 }
810 
811 /*
812  * Perform additional checks on the page to see if we can really use
813  * it. The kernel (kas) pages are always set in the bitmap. However,
814  * boot memory pages (prom_ppages or P_BOOTPAGES) are not in the
815  * bitmap. So we check for them.
816  */
817 static inline int
818 dump_pfn_check(pfn_t pfn)
819 {
820 	page_t *pp = page_numtopp_nolock(pfn);
821 	if (pp == NULL || pp->p_pagenum != pfn ||
822 #if defined(__sparc)
823 	    pp->p_vnode == &promvp ||
824 #else
825 	    PP_ISBOOTPAGES(pp) ||
826 #endif
827 	    pp->p_toxic != 0)
828 		return (0);
829 	return (1);
830 }
831 
832 /*
833  * Check a range to see if all contained pages are available and
834  * return non-zero if the range can be used.
835  */
836 static inline int
837 dump_range_check(pgcnt_t start, pgcnt_t end, pfn_t pfn)
838 {
839 	for (; start < end; start++, pfn++) {
840 		if (BT_TEST(dumpcfg.bitmap, start))
841 			return (0);
842 		if (!dump_pfn_check(pfn))
843 			return (0);
844 	}
845 	return (1);
846 }
847 
848 /*
849  * dumpsys_get_maxmem() is called during panic. Find unused ranges
850  * and use them for buffers. If we find enough memory switch to
851  * parallel bzip2, otherwise use parallel lzjb.
852  *
853  * It searches the dump bitmap in 2 passes. The first time it looks
854  * for CBUF_MAPSIZE ranges. On the second pass it uses small pages.
855  */
856 static void
857 dumpsys_get_maxmem()
858 {
859 	dumpcfg_t *cfg = &dumpcfg;
860 	cbuf_t *endcp = &cfg->cbuf[cfg->ncbuf];
861 	helper_t *endhp = &cfg->helper[cfg->nhelper];
862 	pgcnt_t bitnum, end;
863 	size_t sz, endsz, bz2size;
864 	pfn_t pfn, off;
865 	cbuf_t *cp;
866 	helper_t *hp, *ohp;
867 	dumpmlw_t mlw;
868 	int k;
869 
870 	if (cfg->maxsize == 0 || cfg->clevel < DUMP_CLEVEL_LZJB ||
871 	    (dump_conflags & DUMP_ALL) != 0)
872 		return;
873 
874 	sz = 0;
875 	cfg->found4m = 0;
876 	cfg->foundsm = 0;
877 
878 	/* bitmap of ranges used to estimate which pfns are being used */
879 	bzero(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.rbitmapsize));
880 
881 	/* find ranges that are not being dumped to use for buffers */
882 	dump_init_memlist_walker(&mlw);
883 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
884 		dump_timeleft = dump_timeout;
885 		end = bitnum + CBUF_MAPNP;
886 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
887 		ASSERT(pfn != PFN_INVALID);
888 
889 		/* skip partial range at end of mem segment */
890 		if (mlw.mpleft < CBUF_MAPNP) {
891 			end = bitnum + mlw.mpleft;
892 			continue;
893 		}
894 
895 		/* skip non aligned pages */
896 		off = P2PHASE(pfn, CBUF_MAPNP);
897 		if (off != 0) {
898 			end -= off;
899 			continue;
900 		}
901 
902 		if (!dump_range_check(bitnum, end, pfn))
903 			continue;
904 
905 		ASSERT((sz + CBUF_MAPSIZE) <= cfg->maxvmsize);
906 		hat_devload(kas.a_hat, cfg->maxvm + sz, CBUF_MAPSIZE, pfn,
907 		    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
908 		sz += CBUF_MAPSIZE;
909 		cfg->found4m++;
910 
911 		/* set the bitmap for both ends to be sure to cover the range */
912 		dump_set_used(pfn);
913 		dump_set_used(pfn + CBUF_MAPNP - 1);
914 
915 		if (sz >= cfg->maxsize)
916 			goto foundmax;
917 	}
918 
919 	/* Add small pages if we can't find enough large pages. */
920 	dump_init_memlist_walker(&mlw);
921 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum = end) {
922 		dump_timeleft = dump_timeout;
923 		end = bitnum + CBUF_MAPNP;
924 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
925 		ASSERT(pfn != PFN_INVALID);
926 
927 		/* Find any non-aligned pages at start and end of segment. */
928 		off = P2PHASE(pfn, CBUF_MAPNP);
929 		if (mlw.mpleft < CBUF_MAPNP) {
930 			end = bitnum + mlw.mpleft;
931 		} else if (off != 0) {
932 			end -= off;
933 		} else if (cfg->found4m && dump_test_used(pfn)) {
934 			continue;
935 		}
936 
937 		for (; bitnum < end; bitnum++, pfn++) {
938 			dump_timeleft = dump_timeout;
939 			if (BT_TEST(dumpcfg.bitmap, bitnum))
940 				continue;
941 			if (!dump_pfn_check(pfn))
942 				continue;
943 			ASSERT((sz + PAGESIZE) <= cfg->maxvmsize);
944 			hat_devload(kas.a_hat, cfg->maxvm + sz, PAGESIZE, pfn,
945 			    PROT_READ | PROT_WRITE, HAT_LOAD_NOCONSIST);
946 			sz += PAGESIZE;
947 			cfg->foundsm++;
948 			dump_set_used(pfn);
949 			if (sz >= cfg->maxsize)
950 				goto foundmax;
951 		}
952 	}
953 
954 	/* Fall back to lzjb if we did not get enough memory for bzip2. */
955 	endsz = (cfg->maxsize * cfg->threshold) / cfg->nhelper;
956 	if (sz < endsz) {
957 		cfg->clevel = DUMP_CLEVEL_LZJB;
958 	}
959 
960 	/* Allocate memory for as many helpers as we can. */
961 foundmax:
962 
963 	/* Byte offsets into memory found and mapped above */
964 	endsz = sz;
965 	sz = 0;
966 
967 	/* Set the size for bzip2 state. Only bzip2 needs it. */
968 	bz2size = BZ2_bzCompressInitSize(dump_bzip2_level);
969 
970 	/* Skip the preallocate output buffers. */
971 	cp = &cfg->cbuf[MINCBUFS];
972 
973 	/* Use this to move memory up from the preallocated helpers. */
974 	ohp = cfg->helper;
975 
976 	/* Loop over all helpers and allocate memory. */
977 	for (hp = cfg->helper; hp < endhp; hp++) {
978 
979 		/* Skip preallocated helpers by checking hp->page. */
980 		if (hp->page == NULL) {
981 			if (cfg->clevel <= DUMP_CLEVEL_LZJB) {
982 				/* lzjb needs 2 1-page buffers */
983 				if ((sz + (2 * PAGESIZE)) > endsz)
984 					break;
985 				hp->page = cfg->maxvm + sz;
986 				sz += PAGESIZE;
987 				hp->lzbuf = cfg->maxvm + sz;
988 				sz += PAGESIZE;
989 
990 			} else if (ohp->lzbuf != NULL) {
991 				/* re-use the preallocted lzjb page for bzip2 */
992 				hp->page = ohp->lzbuf;
993 				ohp->lzbuf = NULL;
994 				++ohp;
995 
996 			} else {
997 				/* bzip2 needs a 1-page buffer */
998 				if ((sz + PAGESIZE) > endsz)
999 					break;
1000 				hp->page = cfg->maxvm + sz;
1001 				sz += PAGESIZE;
1002 			}
1003 		}
1004 
1005 		/*
1006 		 * Add output buffers per helper. The number of
1007 		 * buffers per helper is determined by the ratio of
1008 		 * ncbuf to nhelper.
1009 		 */
1010 		for (k = 0; cp < endcp && (sz + CBUF_SIZE) <= endsz &&
1011 		    k < NCBUF_PER_HELPER; k++) {
1012 			cp->state = CBUF_FREEBUF;
1013 			cp->size = CBUF_SIZE;
1014 			cp->buf = cfg->maxvm + sz;
1015 			sz += CBUF_SIZE;
1016 			++cp;
1017 		}
1018 
1019 		/*
1020 		 * bzip2 needs compression state. Use the dumpbzalloc
1021 		 * and dumpbzfree callbacks to allocate the memory.
1022 		 * bzip2 does allocation only at init time.
1023 		 */
1024 		if (cfg->clevel >= DUMP_CLEVEL_BZIP2) {
1025 			if ((sz + bz2size) > endsz) {
1026 				hp->page = NULL;
1027 				break;
1028 			} else {
1029 				hp->bzstream.opaque = &sz;
1030 				hp->bzstream.bzalloc = dumpbzalloc;
1031 				hp->bzstream.bzfree = dumpbzfree;
1032 				(void) BZ2_bzCompressInit(&hp->bzstream,
1033 				    dump_bzip2_level, 0, 0);
1034 				hp->bzstream.opaque = NULL;
1035 			}
1036 		}
1037 	}
1038 
1039 	/* Finish allocating output buffers */
1040 	for (; cp < endcp && (sz + CBUF_SIZE) <= endsz; cp++) {
1041 		cp->state = CBUF_FREEBUF;
1042 		cp->size = CBUF_SIZE;
1043 		cp->buf = cfg->maxvm + sz;
1044 		sz += CBUF_SIZE;
1045 	}
1046 
1047 	/* Enable IS_DUMP_PAGE macro, which checks for pages we took. */
1048 	if (cfg->found4m || cfg->foundsm)
1049 		dump_check_used = 1;
1050 
1051 	ASSERT(sz <= endsz);
1052 }
1053 
1054 static void
1055 dumphdr_init(void)
1056 {
1057 	pgcnt_t npages = 0;
1058 
1059 	ASSERT(MUTEX_HELD(&dump_lock));
1060 
1061 	if (dumphdr == NULL) {
1062 		dumphdr = kmem_zalloc(sizeof (dumphdr_t), KM_SLEEP);
1063 		dumphdr->dump_magic = DUMP_MAGIC;
1064 		dumphdr->dump_version = DUMP_VERSION;
1065 		dumphdr->dump_wordsize = DUMP_WORDSIZE;
1066 		dumphdr->dump_pageshift = PAGESHIFT;
1067 		dumphdr->dump_pagesize = PAGESIZE;
1068 		dumphdr->dump_utsname = utsname;
1069 		(void) strcpy(dumphdr->dump_platform, platform);
1070 		dumpbuf.size = dumpbuf_iosize(maxphys);
1071 		dumpbuf.start = kmem_alloc(dumpbuf.size, KM_SLEEP);
1072 		dumpbuf.end = dumpbuf.start + dumpbuf.size;
1073 		dumpcfg.pids = kmem_alloc(v.v_proc * sizeof (pid_t), KM_SLEEP);
1074 		dumpcfg.helpermap = kmem_zalloc(BT_SIZEOFMAP(NCPU), KM_SLEEP);
1075 		LOCK_INIT_HELD(&dumpcfg.helper_lock);
1076 	}
1077 
1078 	npages = num_phys_pages();
1079 
1080 	if (dumpcfg.bitmapsize != npages) {
1081 		size_t rlen = CBUF_MAPP2R(P2ROUNDUP(npages, CBUF_MAPNP));
1082 		void *map = kmem_alloc(BT_SIZEOFMAP(npages), KM_SLEEP);
1083 		void *rmap = kmem_alloc(BT_SIZEOFMAP(rlen), KM_SLEEP);
1084 
1085 		if (dumpcfg.bitmap != NULL)
1086 			kmem_free(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.
1087 			    bitmapsize));
1088 		if (dumpcfg.rbitmap != NULL)
1089 			kmem_free(dumpcfg.rbitmap, BT_SIZEOFMAP(dumpcfg.
1090 			    rbitmapsize));
1091 		dumpcfg.bitmap = map;
1092 		dumpcfg.bitmapsize = npages;
1093 		dumpcfg.rbitmap = rmap;
1094 		dumpcfg.rbitmapsize = rlen;
1095 	}
1096 }
1097 
1098 /*
1099  * Establish a new dump device.
1100  */
1101 int
1102 dumpinit(vnode_t *vp, char *name, int justchecking)
1103 {
1104 	vnode_t *cvp;
1105 	vattr_t vattr;
1106 	vnode_t *cdev_vp;
1107 	int error = 0;
1108 
1109 	ASSERT(MUTEX_HELD(&dump_lock));
1110 
1111 	dumphdr_init();
1112 
1113 	cvp = common_specvp(vp);
1114 	if (cvp == dumpvp)
1115 		return (0);
1116 
1117 	/*
1118 	 * Determine whether this is a plausible dump device.  We want either:
1119 	 * (1) a real device that's not mounted and has a cb_dump routine, or
1120 	 * (2) a swapfile on some filesystem that has a vop_dump routine.
1121 	 */
1122 	if ((error = VOP_OPEN(&cvp, FREAD | FWRITE, kcred, NULL)) != 0)
1123 		return (error);
1124 
1125 	vattr.va_mask = AT_SIZE | AT_TYPE | AT_RDEV;
1126 	if ((error = VOP_GETATTR(cvp, &vattr, 0, kcred, NULL)) == 0) {
1127 		if (vattr.va_type == VBLK || vattr.va_type == VCHR) {
1128 			if (devopsp[getmajor(vattr.va_rdev)]->
1129 			    devo_cb_ops->cb_dump == nodev)
1130 				error = ENOTSUP;
1131 			else if (vfs_devismounted(vattr.va_rdev))
1132 				error = EBUSY;
1133 			if (strcmp(ddi_driver_name(VTOS(cvp)->s_dip),
1134 			    ZFS_DRIVER) == 0 &&
1135 			    IS_SWAPVP(common_specvp(cvp)))
1136 					error = EBUSY;
1137 		} else {
1138 			if (vn_matchopval(cvp, VOPNAME_DUMP, fs_nosys) ||
1139 			    !IS_SWAPVP(cvp))
1140 				error = ENOTSUP;
1141 		}
1142 	}
1143 
1144 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE)
1145 		error = ENOSPC;
1146 
1147 	if (error || justchecking) {
1148 		(void) VOP_CLOSE(cvp, FREAD | FWRITE, 1, (offset_t)0,
1149 		    kcred, NULL);
1150 		return (error);
1151 	}
1152 
1153 	VN_HOLD(cvp);
1154 
1155 	if (dumpvp != NULL)
1156 		dumpfini();	/* unconfigure the old dump device */
1157 
1158 	dumpvp = cvp;
1159 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
1160 	dumppath = kmem_alloc(strlen(name) + 1, KM_SLEEP);
1161 	(void) strcpy(dumppath, name);
1162 	dumpbuf.iosize = 0;
1163 
1164 	/*
1165 	 * If the dump device is a block device, attempt to open up the
1166 	 * corresponding character device and determine its maximum transfer
1167 	 * size.  We use this information to potentially resize dumpbuf to a
1168 	 * larger and more optimal size for performing i/o to the dump device.
1169 	 */
1170 	if (cvp->v_type == VBLK &&
1171 	    (cdev_vp = makespecvp(VTOS(cvp)->s_dev, VCHR)) != NULL) {
1172 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1173 			size_t blk_size;
1174 			struct dk_cinfo dki;
1175 			struct dk_minfo minf;
1176 
1177 			if (VOP_IOCTL(cdev_vp, DKIOCGMEDIAINFO,
1178 			    (intptr_t)&minf, FKIOCTL, kcred, NULL, NULL)
1179 			    == 0 && minf.dki_lbsize != 0)
1180 				blk_size = minf.dki_lbsize;
1181 			else
1182 				blk_size = DEV_BSIZE;
1183 
1184 			if (VOP_IOCTL(cdev_vp, DKIOCINFO, (intptr_t)&dki,
1185 			    FKIOCTL, kcred, NULL, NULL) == 0) {
1186 				dumpbuf.iosize = dki.dki_maxtransfer * blk_size;
1187 				dumpbuf_resize();
1188 			}
1189 			/*
1190 			 * If we are working with a zvol then dumpify it
1191 			 * if it's not being used as swap.
1192 			 */
1193 			if (strcmp(dki.dki_dname, ZVOL_DRIVER) == 0) {
1194 				if (IS_SWAPVP(common_specvp(cvp)))
1195 					error = EBUSY;
1196 				else if ((error = VOP_IOCTL(cdev_vp,
1197 				    DKIOCDUMPINIT, NULL, FKIOCTL, kcred,
1198 				    NULL, NULL)) != 0)
1199 					dumpfini();
1200 			}
1201 
1202 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1203 			    kcred, NULL);
1204 		}
1205 
1206 		VN_RELE(cdev_vp);
1207 	}
1208 
1209 	cmn_err(CE_CONT, "?dump on %s size %llu MB\n", name, dumpvp_size >> 20);
1210 
1211 	dump_update_clevel();
1212 
1213 	return (error);
1214 }
1215 
1216 void
1217 dumpfini(void)
1218 {
1219 	vattr_t vattr;
1220 	boolean_t is_zfs = B_FALSE;
1221 	vnode_t *cdev_vp;
1222 	ASSERT(MUTEX_HELD(&dump_lock));
1223 
1224 	kmem_free(dumppath, strlen(dumppath) + 1);
1225 
1226 	/*
1227 	 * Determine if we are using zvols for our dump device
1228 	 */
1229 	vattr.va_mask = AT_RDEV;
1230 	if (VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL) == 0) {
1231 		is_zfs = (getmajor(vattr.va_rdev) ==
1232 		    ddi_name_to_major(ZFS_DRIVER)) ? B_TRUE : B_FALSE;
1233 	}
1234 
1235 	/*
1236 	 * If we have a zvol dump device then we call into zfs so
1237 	 * that it may have a chance to cleanup.
1238 	 */
1239 	if (is_zfs &&
1240 	    (cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR)) != NULL) {
1241 		if (VOP_OPEN(&cdev_vp, FREAD | FWRITE, kcred, NULL) == 0) {
1242 			(void) VOP_IOCTL(cdev_vp, DKIOCDUMPFINI, NULL, FKIOCTL,
1243 			    kcred, NULL, NULL);
1244 			(void) VOP_CLOSE(cdev_vp, FREAD | FWRITE, 1, 0,
1245 			    kcred, NULL);
1246 		}
1247 		VN_RELE(cdev_vp);
1248 	}
1249 
1250 	(void) VOP_CLOSE(dumpvp, FREAD | FWRITE, 1, (offset_t)0, kcred, NULL);
1251 
1252 	VN_RELE(dumpvp);
1253 
1254 	dumpvp = NULL;
1255 	dumpvp_size = 0;
1256 	dumppath = NULL;
1257 }
1258 
1259 static offset_t
1260 dumpvp_flush(void)
1261 {
1262 	size_t size = P2ROUNDUP(dumpbuf.cur - dumpbuf.start, PAGESIZE);
1263 	hrtime_t iotime;
1264 	int err;
1265 
1266 	if (dumpbuf.vp_off + size > dumpbuf.vp_limit) {
1267 		dump_ioerr = ENOSPC;
1268 		dumpbuf.vp_off = dumpbuf.vp_limit;
1269 	} else if (size != 0) {
1270 		iotime = gethrtime();
1271 		dumpsync.iowait += iotime - dumpsync.iowaitts;
1272 		if (panicstr)
1273 			err = VOP_DUMP(dumpvp, dumpbuf.start,
1274 			    lbtodb(dumpbuf.vp_off), btod(size), NULL);
1275 		else
1276 			err = vn_rdwr(UIO_WRITE, dumpbuf.cdev_vp != NULL ?
1277 			    dumpbuf.cdev_vp : dumpvp, dumpbuf.start, size,
1278 			    dumpbuf.vp_off, UIO_SYSSPACE, 0, dumpbuf.vp_limit,
1279 			    kcred, 0);
1280 		if (err && dump_ioerr == 0)
1281 			dump_ioerr = err;
1282 		dumpsync.iowaitts = gethrtime();
1283 		dumpsync.iotime += dumpsync.iowaitts - iotime;
1284 		dumpsync.nwrite += size;
1285 		dumpbuf.vp_off += size;
1286 	}
1287 	dumpbuf.cur = dumpbuf.start;
1288 	dump_timeleft = dump_timeout;
1289 	return (dumpbuf.vp_off);
1290 }
1291 
1292 /* maximize write speed by keeping seek offset aligned with size */
1293 void
1294 dumpvp_write(const void *va, size_t size)
1295 {
1296 	size_t len, off, sz;
1297 
1298 	while (size != 0) {
1299 		len = MIN(size, dumpbuf.end - dumpbuf.cur);
1300 		if (len == 0) {
1301 			off = P2PHASE(dumpbuf.vp_off, dumpbuf.size);
1302 			if (off == 0 || !ISP2(dumpbuf.size)) {
1303 				(void) dumpvp_flush();
1304 			} else {
1305 				sz = dumpbuf.size - off;
1306 				dumpbuf.cur = dumpbuf.start + sz;
1307 				(void) dumpvp_flush();
1308 				ovbcopy(dumpbuf.start + sz, dumpbuf.start, off);
1309 				dumpbuf.cur += off;
1310 			}
1311 		} else {
1312 			bcopy(va, dumpbuf.cur, len);
1313 			va = (char *)va + len;
1314 			dumpbuf.cur += len;
1315 			size -= len;
1316 		}
1317 	}
1318 }
1319 
1320 /*ARGSUSED*/
1321 static void
1322 dumpvp_ksyms_write(const void *src, void *dst, size_t size)
1323 {
1324 	dumpvp_write(src, size);
1325 }
1326 
1327 /*
1328  * Mark 'pfn' in the bitmap and dump its translation table entry.
1329  */
1330 void
1331 dump_addpage(struct as *as, void *va, pfn_t pfn)
1332 {
1333 	mem_vtop_t mem_vtop;
1334 	pgcnt_t bitnum;
1335 
1336 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1337 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1338 			dumphdr->dump_npages++;
1339 			BT_SET(dumpcfg.bitmap, bitnum);
1340 		}
1341 		dumphdr->dump_nvtop++;
1342 		mem_vtop.m_as = as;
1343 		mem_vtop.m_va = va;
1344 		mem_vtop.m_pfn = pfn;
1345 		dumpvp_write(&mem_vtop, sizeof (mem_vtop_t));
1346 	}
1347 	dump_timeleft = dump_timeout;
1348 }
1349 
1350 /*
1351  * Mark 'pfn' in the bitmap
1352  */
1353 void
1354 dump_page(pfn_t pfn)
1355 {
1356 	pgcnt_t bitnum;
1357 
1358 	if ((bitnum = dump_pfn_to_bitnum(pfn)) != (pgcnt_t)-1) {
1359 		if (!BT_TEST(dumpcfg.bitmap, bitnum)) {
1360 			dumphdr->dump_npages++;
1361 			BT_SET(dumpcfg.bitmap, bitnum);
1362 		}
1363 	}
1364 	dump_timeleft = dump_timeout;
1365 }
1366 
1367 /*
1368  * Dump the <as, va, pfn> information for a given address space.
1369  * SEGOP_DUMP() will call dump_addpage() for each page in the segment.
1370  */
1371 static void
1372 dump_as(struct as *as)
1373 {
1374 	struct seg *seg;
1375 
1376 	AS_LOCK_ENTER(as, &as->a_lock, RW_READER);
1377 	for (seg = AS_SEGFIRST(as); seg; seg = AS_SEGNEXT(as, seg)) {
1378 		if (seg->s_as != as)
1379 			break;
1380 		if (seg->s_ops == NULL)
1381 			continue;
1382 		SEGOP_DUMP(seg);
1383 	}
1384 	AS_LOCK_EXIT(as, &as->a_lock);
1385 
1386 	if (seg != NULL)
1387 		cmn_err(CE_WARN, "invalid segment %p in address space %p",
1388 		    (void *)seg, (void *)as);
1389 }
1390 
1391 static int
1392 dump_process(pid_t pid)
1393 {
1394 	proc_t *p = sprlock(pid);
1395 
1396 	if (p == NULL)
1397 		return (-1);
1398 	if (p->p_as != &kas) {
1399 		mutex_exit(&p->p_lock);
1400 		dump_as(p->p_as);
1401 		mutex_enter(&p->p_lock);
1402 	}
1403 
1404 	sprunlock(p);
1405 
1406 	return (0);
1407 }
1408 
1409 void
1410 dump_ereports(void)
1411 {
1412 	u_offset_t dumpvp_start;
1413 	erpt_dump_t ed;
1414 
1415 	if (dumpvp == NULL || dumphdr == NULL)
1416 		return;
1417 
1418 	dumpbuf.cur = dumpbuf.start;
1419 	dumpbuf.vp_limit = dumpvp_size - (DUMP_OFFSET + DUMP_LOGSIZE);
1420 	dumpvp_start = dumpbuf.vp_limit - DUMP_ERPTSIZE;
1421 	dumpbuf.vp_off = dumpvp_start;
1422 
1423 	fm_ereport_dump();
1424 	if (panicstr)
1425 		errorq_dump();
1426 
1427 	bzero(&ed, sizeof (ed)); /* indicate end of ereports */
1428 	dumpvp_write(&ed, sizeof (ed));
1429 	(void) dumpvp_flush();
1430 
1431 	if (!panicstr) {
1432 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1433 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1434 		    B_INVAL | B_FORCE, kcred, NULL);
1435 	}
1436 }
1437 
1438 void
1439 dump_messages(void)
1440 {
1441 	log_dump_t ld;
1442 	mblk_t *mctl, *mdata;
1443 	queue_t *q, *qlast;
1444 	u_offset_t dumpvp_start;
1445 
1446 	if (dumpvp == NULL || dumphdr == NULL || log_consq == NULL)
1447 		return;
1448 
1449 	dumpbuf.cur = dumpbuf.start;
1450 	dumpbuf.vp_limit = dumpvp_size - DUMP_OFFSET;
1451 	dumpvp_start = dumpbuf.vp_limit - DUMP_LOGSIZE;
1452 	dumpbuf.vp_off = dumpvp_start;
1453 
1454 	qlast = NULL;
1455 	do {
1456 		for (q = log_consq; q->q_next != qlast; q = q->q_next)
1457 			continue;
1458 		for (mctl = q->q_first; mctl != NULL; mctl = mctl->b_next) {
1459 			dump_timeleft = dump_timeout;
1460 			mdata = mctl->b_cont;
1461 			ld.ld_magic = LOG_MAGIC;
1462 			ld.ld_msgsize = MBLKL(mctl->b_cont);
1463 			ld.ld_csum = checksum32(mctl->b_rptr, MBLKL(mctl));
1464 			ld.ld_msum = checksum32(mdata->b_rptr, MBLKL(mdata));
1465 			dumpvp_write(&ld, sizeof (ld));
1466 			dumpvp_write(mctl->b_rptr, MBLKL(mctl));
1467 			dumpvp_write(mdata->b_rptr, MBLKL(mdata));
1468 		}
1469 	} while ((qlast = q) != log_consq);
1470 
1471 	ld.ld_magic = 0;		/* indicate end of messages */
1472 	dumpvp_write(&ld, sizeof (ld));
1473 	(void) dumpvp_flush();
1474 	if (!panicstr) {
1475 		(void) VOP_PUTPAGE(dumpvp, dumpvp_start,
1476 		    (size_t)(dumpbuf.vp_off - dumpvp_start),
1477 		    B_INVAL | B_FORCE, kcred, NULL);
1478 	}
1479 }
1480 
1481 /*
1482  * The following functions are called on multiple CPUs during dump.
1483  * They must not use most kernel services, because all cross-calls are
1484  * disabled during panic. Therefore, blocking locks and cache flushes
1485  * will not work.
1486  */
1487 
1488 /*
1489  * Copy pages, trapping ECC errors. Also, for robustness, trap data
1490  * access in case something goes wrong in the hat layer and the
1491  * mapping is broken.
1492  */
1493 static int
1494 dump_pagecopy(void *src, void *dst)
1495 {
1496 	long *wsrc = (long *)src;
1497 	long *wdst = (long *)dst;
1498 	const ulong_t ncopies = PAGESIZE / sizeof (long);
1499 	volatile int w = 0;
1500 	volatile int ueoff = -1;
1501 	on_trap_data_t otd;
1502 
1503 	if (on_trap(&otd, OT_DATA_EC | OT_DATA_ACCESS)) {
1504 		if (ueoff == -1)
1505 			ueoff = w * sizeof (long);
1506 		/* report "bad ECC" or "bad address" */
1507 #ifdef _LP64
1508 		if (otd.ot_trap & OT_DATA_EC)
1509 			wdst[w++] = 0x00badecc00badecc;
1510 		else
1511 			wdst[w++] = 0x00badadd00badadd;
1512 #else
1513 		if (otd.ot_trap & OT_DATA_EC)
1514 			wdst[w++] = 0x00badecc;
1515 		else
1516 			wdst[w++] = 0x00badadd;
1517 #endif
1518 	}
1519 	while (w < ncopies) {
1520 		wdst[w] = wsrc[w];
1521 		w++;
1522 	}
1523 	no_trap();
1524 	return (ueoff);
1525 }
1526 
1527 static void
1528 dumpsys_close_cq(cqueue_t *cq, int live)
1529 {
1530 	if (live) {
1531 		mutex_enter(&cq->mutex);
1532 		atomic_dec_uint(&cq->open);
1533 		cv_signal(&cq->cv);
1534 		mutex_exit(&cq->mutex);
1535 	} else {
1536 		atomic_dec_uint(&cq->open);
1537 	}
1538 }
1539 
1540 static inline void
1541 dumpsys_spinlock(lock_t *lp)
1542 {
1543 	uint_t backoff = 0;
1544 	int loop_count = 0;
1545 
1546 	while (LOCK_HELD(lp) || !lock_spin_try(lp)) {
1547 		if (++loop_count >= ncpus) {
1548 			backoff = mutex_lock_backoff(0);
1549 			loop_count = 0;
1550 		} else {
1551 			backoff = mutex_lock_backoff(backoff);
1552 		}
1553 		mutex_lock_delay(backoff);
1554 	}
1555 }
1556 
1557 static inline void
1558 dumpsys_spinunlock(lock_t *lp)
1559 {
1560 	lock_clear(lp);
1561 }
1562 
1563 static inline void
1564 dumpsys_lock(cqueue_t *cq, int live)
1565 {
1566 	if (live)
1567 		mutex_enter(&cq->mutex);
1568 	else
1569 		dumpsys_spinlock(&cq->spinlock);
1570 }
1571 
1572 static inline void
1573 dumpsys_unlock(cqueue_t *cq, int live, int signal)
1574 {
1575 	if (live) {
1576 		if (signal)
1577 			cv_signal(&cq->cv);
1578 		mutex_exit(&cq->mutex);
1579 	} else {
1580 		dumpsys_spinunlock(&cq->spinlock);
1581 	}
1582 }
1583 
1584 static void
1585 dumpsys_wait_cq(cqueue_t *cq, int live)
1586 {
1587 	if (live) {
1588 		cv_wait(&cq->cv, &cq->mutex);
1589 	} else {
1590 		dumpsys_spinunlock(&cq->spinlock);
1591 		while (cq->open)
1592 			if (cq->first)
1593 				break;
1594 		dumpsys_spinlock(&cq->spinlock);
1595 	}
1596 }
1597 
1598 static void
1599 dumpsys_put_cq(cqueue_t *cq, cbuf_t *cp, int newstate, int live)
1600 {
1601 	if (cp == NULL)
1602 		return;
1603 
1604 	dumpsys_lock(cq, live);
1605 
1606 	if (cq->ts != 0) {
1607 		cq->empty += gethrtime() - cq->ts;
1608 		cq->ts = 0;
1609 	}
1610 
1611 	cp->state = newstate;
1612 	cp->next = NULL;
1613 	if (cq->last == NULL)
1614 		cq->first = cp;
1615 	else
1616 		cq->last->next = cp;
1617 	cq->last = cp;
1618 
1619 	dumpsys_unlock(cq, live, 1);
1620 }
1621 
1622 static cbuf_t *
1623 dumpsys_get_cq(cqueue_t *cq, int live)
1624 {
1625 	cbuf_t *cp;
1626 	hrtime_t now = gethrtime();
1627 
1628 	dumpsys_lock(cq, live);
1629 
1630 	/* CONSTCOND */
1631 	while (1) {
1632 		cp = (cbuf_t *)cq->first;
1633 		if (cp == NULL) {
1634 			if (cq->open == 0)
1635 				break;
1636 			dumpsys_wait_cq(cq, live);
1637 			continue;
1638 		}
1639 		cq->first = cp->next;
1640 		if (cq->first == NULL) {
1641 			cq->last = NULL;
1642 			cq->ts = now;
1643 		}
1644 		break;
1645 	}
1646 
1647 	dumpsys_unlock(cq, live, cq->first != NULL || cq->open == 0);
1648 	return (cp);
1649 }
1650 
1651 /*
1652  * Send an error message to the console. If the main task is running
1653  * just write the message via uprintf. If a helper is running the
1654  * message has to be put on a queue for the main task. Setting fmt to
1655  * NULL means flush the error message buffer. If fmt is not NULL, just
1656  * add the text to the existing buffer.
1657  */
1658 static void
1659 dumpsys_errmsg(helper_t *hp, const char *fmt, ...)
1660 {
1661 	dumpsync_t *ds = hp->ds;
1662 	cbuf_t *cp = hp->cperr;
1663 	va_list adx;
1664 
1665 	if (hp->helper == MAINHELPER) {
1666 		if (fmt != NULL) {
1667 			if (ds->neednl) {
1668 				uprintf("\n");
1669 				ds->neednl = 0;
1670 			}
1671 			va_start(adx, fmt);
1672 			vuprintf(fmt, adx);
1673 			va_end(adx);
1674 		}
1675 	} else if (fmt == NULL) {
1676 		if (cp != NULL) {
1677 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1678 			hp->cperr = NULL;
1679 		}
1680 	} else {
1681 		if (hp->cperr == NULL) {
1682 			cp = CQ_GET(freebufq);
1683 			hp->cperr = cp;
1684 			cp->used = 0;
1685 		}
1686 		va_start(adx, fmt);
1687 		cp->used += vsnprintf(cp->buf + cp->used, cp->size - cp->used,
1688 		    fmt, adx);
1689 		va_end(adx);
1690 		if ((cp->used + LOG_MSGSIZE) > cp->size) {
1691 			CQ_PUT(mainq, cp, CBUF_ERRMSG);
1692 			hp->cperr = NULL;
1693 		}
1694 	}
1695 }
1696 
1697 /*
1698  * Write an output buffer to the dump file. If the main task is
1699  * running just write the data. If a helper is running the output is
1700  * placed on a queue for the main task.
1701  */
1702 static void
1703 dumpsys_swrite(helper_t *hp, cbuf_t *cp, size_t used)
1704 {
1705 	dumpsync_t *ds = hp->ds;
1706 
1707 	if (hp->helper == MAINHELPER) {
1708 		HRSTART(ds->perpage, write);
1709 		dumpvp_write(cp->buf, used);
1710 		HRSTOP(ds->perpage, write);
1711 		CQ_PUT(freebufq, cp, CBUF_FREEBUF);
1712 	} else {
1713 		cp->used = used;
1714 		CQ_PUT(mainq, cp, CBUF_WRITE);
1715 	}
1716 }
1717 
1718 /*
1719  * Copy one page within the mapped range. The offset starts at 0 and
1720  * is relative to the first pfn. cp->buf + cp->off is the address of
1721  * the first pfn. If dump_pagecopy returns a UE offset, create an
1722  * error message.  Returns the offset to the next pfn in the range
1723  * selected by the bitmap.
1724  */
1725 static int
1726 dumpsys_copy_page(helper_t *hp, int offset)
1727 {
1728 	cbuf_t *cp = hp->cpin;
1729 	int ueoff;
1730 
1731 	ASSERT(cp->off + offset + PAGESIZE <= cp->size);
1732 	ASSERT(BT_TEST(dumpcfg.bitmap, cp->bitnum));
1733 
1734 	ueoff = dump_pagecopy(cp->buf + cp->off + offset, hp->page);
1735 
1736 	/* ueoff is the offset in the page to a UE error */
1737 	if (ueoff != -1) {
1738 		uint64_t pa = ptob(cp->pfn) + offset + ueoff;
1739 
1740 		dumpsys_errmsg(hp, "cpu %d: memory error at PA 0x%08x.%08x\n",
1741 		    CPU->cpu_id, (uint32_t)(pa >> 32), (uint32_t)pa);
1742 	}
1743 
1744 	/*
1745 	 * Advance bitnum and offset to the next input page for the
1746 	 * next call to this function.
1747 	 */
1748 	offset += PAGESIZE;
1749 	cp->bitnum++;
1750 	while (cp->off + offset < cp->size) {
1751 		if (BT_TEST(dumpcfg.bitmap, cp->bitnum))
1752 			break;
1753 		offset += PAGESIZE;
1754 		cp->bitnum++;
1755 	}
1756 
1757 	return (offset);
1758 }
1759 
1760 /*
1761  * Read the helper queue, and copy one mapped page. Return 0 when
1762  * done. Return 1 when a page has been copied into hp->page.
1763  */
1764 static int
1765 dumpsys_sread(helper_t *hp)
1766 {
1767 	dumpsync_t *ds = hp->ds;
1768 
1769 	/* CONSTCOND */
1770 	while (1) {
1771 
1772 		/* Find the next input buffer. */
1773 		if (hp->cpin == NULL) {
1774 			HRSTART(hp->perpage, inwait);
1775 
1776 			/* CONSTCOND */
1777 			while (1) {
1778 				hp->cpin = CQ_GET(helperq);
1779 				dump_timeleft = dump_timeout;
1780 
1781 				/*
1782 				 * NULL return means the helper queue
1783 				 * is closed and empty.
1784 				 */
1785 				if (hp->cpin == NULL)
1786 					break;
1787 
1788 				/* Have input, check for dump I/O error. */
1789 				if (!dump_ioerr)
1790 					break;
1791 
1792 				/*
1793 				 * If an I/O error occurs, stay in the
1794 				 * loop in order to empty the helper
1795 				 * queue. Return the buffers to the
1796 				 * main task to unmap and free it.
1797 				 */
1798 				hp->cpin->used = 0;
1799 				CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1800 			}
1801 			HRSTOP(hp->perpage, inwait);
1802 
1803 			/* Stop here when the helper queue is closed. */
1804 			if (hp->cpin == NULL)
1805 				break;
1806 
1807 			/* Set the offset=0 to get the first pfn. */
1808 			hp->in = 0;
1809 
1810 			/* Set the total processed to 0 */
1811 			hp->used = 0;
1812 		}
1813 
1814 		/* Process the next page. */
1815 		if (hp->used < hp->cpin->used) {
1816 
1817 			/*
1818 			 * Get the next page from the input buffer and
1819 			 * return a copy.
1820 			 */
1821 			ASSERT(hp->in != -1);
1822 			HRSTART(hp->perpage, copy);
1823 			hp->in = dumpsys_copy_page(hp, hp->in);
1824 			hp->used += PAGESIZE;
1825 			HRSTOP(hp->perpage, copy);
1826 			break;
1827 
1828 		} else {
1829 
1830 			/*
1831 			 * Done with the input. Flush the VM and
1832 			 * return the buffer to the main task.
1833 			 */
1834 			if (panicstr && hp->helper != MAINHELPER)
1835 				hat_flush_range(kas.a_hat,
1836 				    hp->cpin->buf, hp->cpin->size);
1837 			dumpsys_errmsg(hp, NULL);
1838 			CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
1839 			hp->cpin = NULL;
1840 		}
1841 	}
1842 
1843 	return (hp->cpin != NULL);
1844 }
1845 
1846 /*
1847  * Compress size bytes starting at buf with bzip2
1848  * mode:
1849  *	BZ_RUN		add one more compressed page
1850  *	BZ_FINISH	no more input, flush the state
1851  */
1852 static void
1853 dumpsys_bzrun(helper_t *hp, void *buf, size_t size, int mode)
1854 {
1855 	dumpsync_t *ds = hp->ds;
1856 	const int CSIZE = sizeof (dumpcsize_t);
1857 	bz_stream *ps = &hp->bzstream;
1858 	int rc = 0;
1859 	uint32_t csize;
1860 	dumpcsize_t cs;
1861 
1862 	/* Set input pointers to new input page */
1863 	if (size > 0) {
1864 		ps->avail_in = size;
1865 		ps->next_in = buf;
1866 	}
1867 
1868 	/* CONSTCOND */
1869 	while (1) {
1870 
1871 		/* Quit when all input has been consumed */
1872 		if (ps->avail_in == 0 && mode == BZ_RUN)
1873 			break;
1874 
1875 		/* Get a new output buffer */
1876 		if (hp->cpout == NULL) {
1877 			HRSTART(hp->perpage, outwait);
1878 			hp->cpout = CQ_GET(freebufq);
1879 			HRSTOP(hp->perpage, outwait);
1880 			ps->avail_out = hp->cpout->size - CSIZE;
1881 			ps->next_out = hp->cpout->buf + CSIZE;
1882 		}
1883 
1884 		/* Compress input, or finalize */
1885 		HRSTART(hp->perpage, compress);
1886 		rc = BZ2_bzCompress(ps, mode);
1887 		HRSTOP(hp->perpage, compress);
1888 
1889 		/* Check for error */
1890 		if (mode == BZ_RUN && rc != BZ_RUN_OK) {
1891 			dumpsys_errmsg(hp, "%d: BZ_RUN error %s at page %lx\n",
1892 			    hp->helper, BZ2_bzErrorString(rc),
1893 			    hp->cpin->pagenum);
1894 			break;
1895 		}
1896 
1897 		/* Write the buffer if it is full, or we are flushing */
1898 		if (ps->avail_out == 0 || mode == BZ_FINISH) {
1899 			csize = hp->cpout->size - CSIZE - ps->avail_out;
1900 			cs = DUMP_SET_TAG(csize, hp->tag);
1901 			if (csize > 0) {
1902 				(void) memcpy(hp->cpout->buf, &cs, CSIZE);
1903 				dumpsys_swrite(hp, hp->cpout, csize + CSIZE);
1904 				hp->cpout = NULL;
1905 			}
1906 		}
1907 
1908 		/* Check for final complete */
1909 		if (mode == BZ_FINISH) {
1910 			if (rc == BZ_STREAM_END)
1911 				break;
1912 			if (rc != BZ_FINISH_OK) {
1913 				dumpsys_errmsg(hp, "%d: BZ_FINISH error %s\n",
1914 				    hp->helper, BZ2_bzErrorString(rc));
1915 				break;
1916 			}
1917 		}
1918 	}
1919 
1920 	/* Cleanup state and buffers */
1921 	if (mode == BZ_FINISH) {
1922 
1923 		/* Reset state so that it is re-usable. */
1924 		(void) BZ2_bzCompressReset(&hp->bzstream);
1925 
1926 		/* Give any unused outout buffer to the main task */
1927 		if (hp->cpout != NULL) {
1928 			hp->cpout->used = 0;
1929 			CQ_PUT(mainq, hp->cpout, CBUF_ERRMSG);
1930 			hp->cpout = NULL;
1931 		}
1932 	}
1933 }
1934 
1935 static void
1936 dumpsys_bz2compress(helper_t *hp)
1937 {
1938 	dumpsync_t *ds = hp->ds;
1939 	dumpstreamhdr_t sh;
1940 
1941 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
1942 	sh.stream_pagenum = (pgcnt_t)-1;
1943 	sh.stream_npages = 0;
1944 	hp->cpin = NULL;
1945 	hp->cpout = NULL;
1946 	hp->cperr = NULL;
1947 	hp->in = 0;
1948 	hp->out = 0;
1949 	hp->bzstream.avail_in = 0;
1950 
1951 	/* Bump reference to mainq while we are running */
1952 	CQ_OPEN(mainq);
1953 
1954 	/* Get one page at a time */
1955 	while (dumpsys_sread(hp)) {
1956 		if (sh.stream_pagenum != hp->cpin->pagenum) {
1957 			sh.stream_pagenum = hp->cpin->pagenum;
1958 			sh.stream_npages = btop(hp->cpin->used);
1959 			dumpsys_bzrun(hp, &sh, sizeof (sh), BZ_RUN);
1960 		}
1961 		dumpsys_bzrun(hp, hp->page, PAGESIZE, 0);
1962 	}
1963 
1964 	/* Done with input, flush any partial buffer */
1965 	if (sh.stream_pagenum != (pgcnt_t)-1) {
1966 		dumpsys_bzrun(hp, NULL, 0, BZ_FINISH);
1967 		dumpsys_errmsg(hp, NULL);
1968 	}
1969 
1970 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
1971 
1972 	/* Decrement main queue count, we are done */
1973 	CQ_CLOSE(mainq);
1974 }
1975 
1976 /*
1977  * Compress with lzjb
1978  * write stream block if full or size==0
1979  * if csize==0 write stream header, else write <csize, data>
1980  * size==0 is a call to flush a buffer
1981  * hp->cpout is the buffer we are flushing or filling
1982  * hp->out is the next index to fill data
1983  * osize is either csize+data, or the size of a stream header
1984  */
1985 static void
1986 dumpsys_lzjbrun(helper_t *hp, size_t csize, void *buf, size_t size)
1987 {
1988 	dumpsync_t *ds = hp->ds;
1989 	const int CSIZE = sizeof (dumpcsize_t);
1990 	dumpcsize_t cs;
1991 	size_t osize = csize > 0 ? CSIZE + size : size;
1992 
1993 	/* If flush, and there is no buffer, just return */
1994 	if (size == 0 && hp->cpout == NULL)
1995 		return;
1996 
1997 	/* If flush, or cpout is full, write it out */
1998 	if (size == 0 ||
1999 	    hp->cpout != NULL && hp->out + osize > hp->cpout->size) {
2000 
2001 		/* Set tag+size word at the front of the stream block. */
2002 		cs = DUMP_SET_TAG(hp->out - CSIZE, hp->tag);
2003 		(void) memcpy(hp->cpout->buf, &cs, CSIZE);
2004 
2005 		/* Write block to dump file. */
2006 		dumpsys_swrite(hp, hp->cpout, hp->out);
2007 
2008 		/* Clear pointer to indicate we need a new buffer */
2009 		hp->cpout = NULL;
2010 
2011 		/* flushing, we are done */
2012 		if (size == 0)
2013 			return;
2014 	}
2015 
2016 	/* Get an output buffer if we dont have one. */
2017 	if (hp->cpout == NULL) {
2018 		HRSTART(hp->perpage, outwait);
2019 		hp->cpout = CQ_GET(freebufq);
2020 		HRSTOP(hp->perpage, outwait);
2021 		hp->out = CSIZE;
2022 	}
2023 
2024 	/* Store csize word. This is the size of compressed data. */
2025 	if (csize > 0) {
2026 		cs = DUMP_SET_TAG(csize, 0);
2027 		(void) memcpy(hp->cpout->buf + hp->out, &cs, CSIZE);
2028 		hp->out += CSIZE;
2029 	}
2030 
2031 	/* Store the data. */
2032 	(void) memcpy(hp->cpout->buf + hp->out, buf, size);
2033 	hp->out += size;
2034 }
2035 
2036 static void
2037 dumpsys_lzjbcompress(helper_t *hp)
2038 {
2039 	dumpsync_t *ds = hp->ds;
2040 	size_t csize;
2041 	dumpstreamhdr_t sh;
2042 
2043 	(void) strcpy(sh.stream_magic, DUMP_STREAM_MAGIC);
2044 	sh.stream_pagenum = (pfn_t)-1;
2045 	sh.stream_npages = 0;
2046 	hp->cpin = NULL;
2047 	hp->cpout = NULL;
2048 	hp->cperr = NULL;
2049 	hp->in = 0;
2050 	hp->out = 0;
2051 
2052 	/* Bump reference to mainq while we are running */
2053 	CQ_OPEN(mainq);
2054 
2055 	/* Get one page at a time */
2056 	while (dumpsys_sread(hp)) {
2057 
2058 		/* Create a stream header for each new input map */
2059 		if (sh.stream_pagenum != hp->cpin->pagenum) {
2060 			sh.stream_pagenum = hp->cpin->pagenum;
2061 			sh.stream_npages = btop(hp->cpin->used);
2062 			dumpsys_lzjbrun(hp, 0, &sh, sizeof (sh));
2063 		}
2064 
2065 		/* Compress one page */
2066 		HRSTART(hp->perpage, compress);
2067 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2068 		HRSTOP(hp->perpage, compress);
2069 
2070 		/* Add csize+data to output block */
2071 		ASSERT(csize > 0 && csize <= PAGESIZE);
2072 		dumpsys_lzjbrun(hp, csize, hp->lzbuf, csize);
2073 	}
2074 
2075 	/* Done with input, flush any partial buffer */
2076 	if (sh.stream_pagenum != (pfn_t)-1) {
2077 		dumpsys_lzjbrun(hp, 0, NULL, 0);
2078 		dumpsys_errmsg(hp, NULL);
2079 	}
2080 
2081 	ASSERT(hp->cpin == NULL && hp->cpout == NULL && hp->cperr == NULL);
2082 
2083 	/* Decrement main queue count, we are done */
2084 	CQ_CLOSE(mainq);
2085 }
2086 
2087 /*
2088  * Dump helper called from panic_idle() to compress pages.  CPUs in
2089  * this path must not call most kernel services.
2090  *
2091  * During panic, all but one of the CPUs is idle. These CPUs are used
2092  * as helpers working in parallel to copy and compress memory
2093  * pages. During a panic, however, these processors cannot call any
2094  * kernel services. This is because mutexes become no-ops during
2095  * panic, and, cross-call interrupts are inhibited.  Therefore, during
2096  * panic dump the helper CPUs communicate with the panic CPU using
2097  * memory variables. All memory mapping and I/O is performed by the
2098  * panic CPU.
2099  */
2100 void
2101 dumpsys_helper()
2102 {
2103 	dumpsys_spinlock(&dumpcfg.helper_lock);
2104 	if (dumpcfg.helpers_wanted) {
2105 		helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2106 
2107 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2108 			if (hp->helper == FREEHELPER) {
2109 				hp->helper = CPU->cpu_id;
2110 				BT_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2111 
2112 				dumpsys_spinunlock(&dumpcfg.helper_lock);
2113 
2114 				if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2115 					dumpsys_lzjbcompress(hp);
2116 				else
2117 					dumpsys_bz2compress(hp);
2118 
2119 				hp->helper = DONEHELPER;
2120 				return;
2121 			}
2122 		}
2123 	}
2124 	dumpsys_spinunlock(&dumpcfg.helper_lock);
2125 }
2126 
2127 /*
2128  * Dump helper for live dumps.
2129  * These run as a system task.
2130  */
2131 static void
2132 dumpsys_live_helper(void *arg)
2133 {
2134 	helper_t *hp = arg;
2135 
2136 	BT_ATOMIC_SET(dumpcfg.helpermap, CPU->cpu_seqid);
2137 	if (dumpcfg.clevel < DUMP_CLEVEL_BZIP2)
2138 		dumpsys_lzjbcompress(hp);
2139 	else
2140 		dumpsys_bz2compress(hp);
2141 }
2142 
2143 /*
2144  * Compress one page with lzjb (single threaded case)
2145  */
2146 static void
2147 dumpsys_lzjb_page(helper_t *hp, cbuf_t *cp)
2148 {
2149 	dumpsync_t *ds = hp->ds;
2150 	uint32_t csize;
2151 
2152 	hp->helper = MAINHELPER;
2153 	hp->in = 0;
2154 	hp->used = 0;
2155 	hp->cpin = cp;
2156 	while (hp->used < cp->used) {
2157 		HRSTART(hp->perpage, copy);
2158 		hp->in = dumpsys_copy_page(hp, hp->in);
2159 		hp->used += PAGESIZE;
2160 		HRSTOP(hp->perpage, copy);
2161 
2162 		HRSTART(hp->perpage, compress);
2163 		csize = compress(hp->page, hp->lzbuf, PAGESIZE);
2164 		HRSTOP(hp->perpage, compress);
2165 
2166 		HRSTART(hp->perpage, write);
2167 		dumpvp_write(&csize, sizeof (csize));
2168 		dumpvp_write(hp->lzbuf, csize);
2169 		HRSTOP(hp->perpage, write);
2170 	}
2171 	CQ_PUT(mainq, hp->cpin, CBUF_USEDMAP);
2172 	hp->cpin = NULL;
2173 }
2174 
2175 /*
2176  * Main task to dump pages. This is called on the dump CPU.
2177  */
2178 static void
2179 dumpsys_main_task(void *arg)
2180 {
2181 	dumpsync_t *ds = arg;
2182 	pgcnt_t pagenum = 0, bitnum = 0, hibitnum;
2183 	dumpmlw_t mlw;
2184 	cbuf_t *cp;
2185 	pgcnt_t baseoff, pfnoff;
2186 	pfn_t base, pfn;
2187 	int sec;
2188 
2189 	dump_init_memlist_walker(&mlw);
2190 
2191 	/* CONSTCOND */
2192 	while (1) {
2193 
2194 		if (ds->percent > ds->percent_done) {
2195 			ds->percent_done = ds->percent;
2196 			sec = (gethrtime() - ds->start) / 1000 / 1000 / 1000;
2197 			uprintf("^\r%2d:%02d %3d%% done",
2198 			    sec / 60, sec % 60, ds->percent);
2199 			ds->neednl = 1;
2200 		}
2201 
2202 		while (CQ_IS_EMPTY(mainq) && !CQ_IS_EMPTY(writerq)) {
2203 
2204 			/* the writerq never blocks */
2205 			cp = CQ_GET(writerq);
2206 			if (cp == NULL)
2207 				break;
2208 
2209 			dump_timeleft = dump_timeout;
2210 
2211 			HRSTART(ds->perpage, write);
2212 			dumpvp_write(cp->buf, cp->used);
2213 			HRSTOP(ds->perpage, write);
2214 
2215 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2216 		}
2217 
2218 		/*
2219 		 * Wait here for some buffers to process. Returns NULL
2220 		 * when all helpers have terminated and all buffers
2221 		 * have been processed.
2222 		 */
2223 		cp = CQ_GET(mainq);
2224 
2225 		if (cp == NULL) {
2226 
2227 			/* Drain the write queue. */
2228 			if (!CQ_IS_EMPTY(writerq))
2229 				continue;
2230 
2231 			/* Main task exits here. */
2232 			break;
2233 		}
2234 
2235 		dump_timeleft = dump_timeout;
2236 
2237 		switch (cp->state) {
2238 
2239 		case CBUF_FREEMAP:
2240 
2241 			/*
2242 			 * Note that we drop CBUF_FREEMAP buffers on
2243 			 * the floor (they will not be on any cqueue)
2244 			 * when we no longer need them.
2245 			 */
2246 			if (bitnum >= dumpcfg.bitmapsize)
2247 				break;
2248 
2249 			if (dump_ioerr) {
2250 				bitnum = dumpcfg.bitmapsize;
2251 				CQ_CLOSE(helperq);
2252 				break;
2253 			}
2254 
2255 			HRSTART(ds->perpage, bitmap);
2256 			for (; bitnum < dumpcfg.bitmapsize; bitnum++)
2257 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2258 					break;
2259 			HRSTOP(ds->perpage, bitmap);
2260 			dump_timeleft = dump_timeout;
2261 
2262 			if (bitnum >= dumpcfg.bitmapsize) {
2263 				CQ_CLOSE(helperq);
2264 				break;
2265 			}
2266 
2267 			/*
2268 			 * Try to map CBUF_MAPSIZE ranges. Can't
2269 			 * assume that memory segment size is a
2270 			 * multiple of CBUF_MAPSIZE. Can't assume that
2271 			 * the segment starts on a CBUF_MAPSIZE
2272 			 * boundary.
2273 			 */
2274 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2275 			ASSERT(pfn != PFN_INVALID);
2276 			ASSERT(bitnum + mlw.mpleft <= dumpcfg.bitmapsize);
2277 
2278 			base = P2ALIGN(pfn, CBUF_MAPNP);
2279 			if (base < mlw.mpaddr) {
2280 				base = mlw.mpaddr;
2281 				baseoff = P2PHASE(base, CBUF_MAPNP);
2282 			} else {
2283 				baseoff = 0;
2284 			}
2285 
2286 			pfnoff = pfn - base;
2287 			if (pfnoff + mlw.mpleft < CBUF_MAPNP) {
2288 				hibitnum = bitnum + mlw.mpleft;
2289 				cp->size = ptob(pfnoff + mlw.mpleft);
2290 			} else {
2291 				hibitnum = bitnum - pfnoff + CBUF_MAPNP -
2292 				    baseoff;
2293 				cp->size = CBUF_MAPSIZE - ptob(baseoff);
2294 			}
2295 
2296 			cp->pfn = pfn;
2297 			cp->bitnum = bitnum++;
2298 			cp->pagenum = pagenum++;
2299 			cp->off = ptob(pfnoff);
2300 
2301 			for (; bitnum < hibitnum; bitnum++)
2302 				if (BT_TEST(dumpcfg.bitmap, bitnum))
2303 					pagenum++;
2304 
2305 			dump_timeleft = dump_timeout;
2306 			cp->used = ptob(pagenum - cp->pagenum);
2307 
2308 			HRSTART(ds->perpage, map);
2309 			hat_devload(kas.a_hat, cp->buf, cp->size, base,
2310 			    PROT_READ, HAT_LOAD_NOCONSIST);
2311 			HRSTOP(ds->perpage, map);
2312 
2313 			ds->pages_mapped += btop(cp->size);
2314 			ds->pages_used += pagenum - cp->pagenum;
2315 
2316 			CQ_OPEN(mainq);
2317 
2318 			/*
2319 			 * If there are no helpers the main task does
2320 			 * non-streams lzjb compress.
2321 			 */
2322 			if (dumpcfg.clevel == 0) {
2323 				dumpsys_lzjb_page(dumpcfg.helper, cp);
2324 				break;
2325 			}
2326 
2327 			/* pass mapped pages to a helper */
2328 			CQ_PUT(helperq, cp, CBUF_INREADY);
2329 
2330 			/* the last page was done */
2331 			if (bitnum >= dumpcfg.bitmapsize)
2332 				CQ_CLOSE(helperq);
2333 
2334 			break;
2335 
2336 		case CBUF_USEDMAP:
2337 
2338 			ds->npages += btop(cp->used);
2339 
2340 			HRSTART(ds->perpage, unmap);
2341 			hat_unload(kas.a_hat, cp->buf, cp->size, HAT_UNLOAD);
2342 			HRSTOP(ds->perpage, unmap);
2343 
2344 			if (bitnum < dumpcfg.bitmapsize)
2345 				CQ_PUT(mainq, cp, CBUF_FREEMAP);
2346 			CQ_CLOSE(mainq);
2347 
2348 			ASSERT(ds->npages <= dumphdr->dump_npages);
2349 			ds->percent = ds->npages * 100LL / dumphdr->dump_npages;
2350 			break;
2351 
2352 		case CBUF_WRITE:
2353 
2354 			CQ_PUT(writerq, cp, CBUF_WRITE);
2355 			break;
2356 
2357 		case CBUF_ERRMSG:
2358 
2359 			if (cp->used > 0) {
2360 				cp->buf[cp->size - 2] = '\n';
2361 				cp->buf[cp->size - 1] = '\0';
2362 				if (ds->neednl) {
2363 					uprintf("\n%s", cp->buf);
2364 					ds->neednl = 0;
2365 				} else {
2366 					uprintf("%s", cp->buf);
2367 				}
2368 				/* wait for console output */
2369 				drv_usecwait(200000);
2370 				dump_timeleft = dump_timeout;
2371 			}
2372 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2373 			break;
2374 
2375 		default:
2376 			uprintf("dump: unexpected buffer state %d, "
2377 			    "buffer will be lost\n", cp->state);
2378 			break;
2379 
2380 		} /* end switch */
2381 
2382 	} /* end while(1) */
2383 }
2384 
2385 #ifdef	COLLECT_METRICS
2386 size_t
2387 dumpsys_metrics(dumpsync_t *ds, char *buf, size_t size)
2388 {
2389 	dumpcfg_t *cfg = &dumpcfg;
2390 	int myid = CPU->cpu_seqid;
2391 	int i, compress_ratio;
2392 	int sec, iorate;
2393 	helper_t *hp, *hpend = &cfg->helper[cfg->nhelper];
2394 	char *e = buf + size;
2395 	char *p = buf;
2396 
2397 	sec = ds->elapsed / (1000 * 1000 * 1000ULL);
2398 	if (sec < 1)
2399 		sec = 1;
2400 
2401 	if (ds->iotime < 1)
2402 		ds->iotime = 1;
2403 	iorate = (ds->nwrite * 100000ULL) / ds->iotime;
2404 
2405 	compress_ratio = 100LL * ds->npages / btopr(ds->nwrite + 1);
2406 
2407 #define	P(...) (p += p < e ? snprintf(p, e - p, __VA_ARGS__) : 0)
2408 
2409 	P("Master cpu_seqid,%d\n", CPU->cpu_seqid);
2410 	P("Master cpu_id,%d\n", CPU->cpu_id);
2411 	P("dump_flags,0x%x\n", dumphdr->dump_flags);
2412 	P("dump_ioerr,%d\n", dump_ioerr);
2413 
2414 	P("Helpers:\n");
2415 	for (i = 0; i < ncpus; i++) {
2416 		if ((i & 15) == 0)
2417 			P(",,%03d,", i);
2418 		if (i == myid)
2419 			P("   M");
2420 		else if (BT_TEST(cfg->helpermap, i))
2421 			P("%4d", cpu_seq[i]->cpu_id);
2422 		else
2423 			P("   *");
2424 		if ((i & 15) == 15)
2425 			P("\n");
2426 	}
2427 
2428 	P("ncbuf_used,%d\n", cfg->ncbuf_used);
2429 	P("ncmap,%d\n", cfg->ncmap);
2430 
2431 	P("Found %ldM ranges,%ld\n", (CBUF_MAPSIZE / DUMP_1MB), cfg->found4m);
2432 	P("Found small pages,%ld\n", cfg->foundsm);
2433 
2434 	P("Compression level,%d\n", cfg->clevel);
2435 	P("Compression type,%s %s\n", cfg->clevel == 0 ? "serial" : "parallel",
2436 	    cfg->clevel >= DUMP_CLEVEL_BZIP2 ? "bzip2" : "lzjb");
2437 	P("Compression ratio,%d.%02d\n", compress_ratio / 100, compress_ratio %
2438 	    100);
2439 	P("nhelper_used,%d\n", cfg->nhelper_used);
2440 
2441 	P("Dump I/O rate MBS,%d.%02d\n", iorate / 100, iorate % 100);
2442 	P("..total bytes,%lld\n", (u_longlong_t)ds->nwrite);
2443 	P("..total nsec,%lld\n", (u_longlong_t)ds->iotime);
2444 	P("dumpbuf.iosize,%ld\n", dumpbuf.iosize);
2445 	P("dumpbuf.size,%ld\n", dumpbuf.size);
2446 
2447 	P("Dump pages/sec,%llu\n", (u_longlong_t)ds->npages / sec);
2448 	P("Dump pages,%llu\n", (u_longlong_t)ds->npages);
2449 	P("Dump time,%d\n", sec);
2450 
2451 	if (ds->pages_mapped > 0)
2452 		P("per-cent map utilization,%d\n", (int)((100 * ds->pages_used)
2453 		    / ds->pages_mapped));
2454 
2455 	P("\nPer-page metrics:\n");
2456 	if (ds->npages > 0) {
2457 		for (hp = cfg->helper; hp != hpend; hp++) {
2458 #define	PERPAGE(x)	ds->perpage.x += hp->perpage.x;
2459 			PERPAGES;
2460 #undef PERPAGE
2461 		}
2462 #define	PERPAGE(x) \
2463 		P("%s nsec/page,%d\n", #x, (int)(ds->perpage.x / ds->npages));
2464 		PERPAGES;
2465 #undef PERPAGE
2466 		P("freebufq.empty,%d\n", (int)(ds->freebufq.empty /
2467 		    ds->npages));
2468 		P("helperq.empty,%d\n", (int)(ds->helperq.empty /
2469 		    ds->npages));
2470 		P("writerq.empty,%d\n", (int)(ds->writerq.empty /
2471 		    ds->npages));
2472 		P("mainq.empty,%d\n", (int)(ds->mainq.empty / ds->npages));
2473 
2474 		P("I/O wait nsec/page,%llu\n", (u_longlong_t)(ds->iowait /
2475 		    ds->npages));
2476 	}
2477 #undef P
2478 	if (p < e)
2479 		bzero(p, e - p);
2480 	return (p - buf);
2481 }
2482 #endif	/* COLLECT_METRICS */
2483 
2484 /*
2485  * Dump the system.
2486  */
2487 void
2488 dumpsys(void)
2489 {
2490 	dumpsync_t *ds = &dumpsync;
2491 	taskq_t *livetaskq = NULL;
2492 	pfn_t pfn;
2493 	pgcnt_t bitnum;
2494 	proc_t *p;
2495 	helper_t *hp, *hpend = &dumpcfg.helper[dumpcfg.nhelper];
2496 	cbuf_t *cp;
2497 	pid_t npids, pidx;
2498 	char *content;
2499 	char *buf;
2500 	size_t size;
2501 	int save_dump_clevel;
2502 	dumpmlw_t mlw;
2503 	dumpcsize_t datatag;
2504 	dumpdatahdr_t datahdr;
2505 
2506 	if (dumpvp == NULL || dumphdr == NULL) {
2507 		uprintf("skipping system dump - no dump device configured\n");
2508 		if (panicstr) {
2509 			dumpcfg.helpers_wanted = 0;
2510 			dumpsys_spinunlock(&dumpcfg.helper_lock);
2511 		}
2512 		return;
2513 	}
2514 	dumpbuf.cur = dumpbuf.start;
2515 
2516 	/* clear the sync variables */
2517 	ASSERT(dumpcfg.nhelper > 0);
2518 	bzero(ds, sizeof (*ds));
2519 	ds->dumpcpu = CPU->cpu_id;
2520 
2521 	/*
2522 	 * Calculate the starting block for dump.  If we're dumping on a
2523 	 * swap device, start 1/5 of the way in; otherwise, start at the
2524 	 * beginning.  And never use the first page -- it may be a disk label.
2525 	 */
2526 	if (dumpvp->v_flag & VISSWAP)
2527 		dumphdr->dump_start = P2ROUNDUP(dumpvp_size / 5, DUMP_OFFSET);
2528 	else
2529 		dumphdr->dump_start = DUMP_OFFSET;
2530 
2531 	dumphdr->dump_flags = DF_VALID | DF_COMPLETE | DF_LIVE | DF_COMPRESSED;
2532 	dumphdr->dump_crashtime = gethrestime_sec();
2533 	dumphdr->dump_npages = 0;
2534 	dumphdr->dump_nvtop = 0;
2535 	bzero(dumpcfg.bitmap, BT_SIZEOFMAP(dumpcfg.bitmapsize));
2536 	dump_timeleft = dump_timeout;
2537 
2538 	if (panicstr) {
2539 		dumphdr->dump_flags &= ~DF_LIVE;
2540 		(void) VOP_DUMPCTL(dumpvp, DUMP_FREE, NULL, NULL);
2541 		(void) VOP_DUMPCTL(dumpvp, DUMP_ALLOC, NULL, NULL);
2542 		(void) vsnprintf(dumphdr->dump_panicstring, DUMP_PANICSIZE,
2543 		    panicstr, panicargs);
2544 
2545 	}
2546 
2547 	if (dump_conflags & DUMP_ALL)
2548 		content = "all";
2549 	else if (dump_conflags & DUMP_CURPROC)
2550 		content = "kernel + curproc";
2551 	else
2552 		content = "kernel";
2553 	uprintf("dumping to %s, offset %lld, content: %s\n", dumppath,
2554 	    dumphdr->dump_start, content);
2555 
2556 	/* Make sure nodename is current */
2557 	bcopy(utsname.nodename, dumphdr->dump_utsname.nodename, SYS_NMLN);
2558 
2559 	/*
2560 	 * If this is a live dump, try to open a VCHR vnode for better
2561 	 * performance. We must take care to flush the buffer cache
2562 	 * first.
2563 	 */
2564 	if (!panicstr) {
2565 		vnode_t *cdev_vp, *cmn_cdev_vp;
2566 
2567 		ASSERT(dumpbuf.cdev_vp == NULL);
2568 		cdev_vp = makespecvp(VTOS(dumpvp)->s_dev, VCHR);
2569 		if (cdev_vp != NULL) {
2570 			cmn_cdev_vp = common_specvp(cdev_vp);
2571 			if (VOP_OPEN(&cmn_cdev_vp, FREAD | FWRITE, kcred, NULL)
2572 			    == 0) {
2573 				if (vn_has_cached_data(dumpvp))
2574 					(void) pvn_vplist_dirty(dumpvp, 0, NULL,
2575 					    B_INVAL | B_TRUNC, kcred);
2576 				dumpbuf.cdev_vp = cmn_cdev_vp;
2577 			} else {
2578 				VN_RELE(cdev_vp);
2579 			}
2580 		}
2581 	}
2582 
2583 	/*
2584 	 * Store a hires timestamp so we can look it up during debugging.
2585 	 */
2586 	lbolt_debug_entry();
2587 
2588 	/*
2589 	 * Leave room for the message and ereport save areas and terminal dump
2590 	 * header.
2591 	 */
2592 	dumpbuf.vp_limit = dumpvp_size - DUMP_LOGSIZE - DUMP_OFFSET -
2593 	    DUMP_ERPTSIZE;
2594 
2595 	/*
2596 	 * Write out the symbol table.  It's no longer compressed,
2597 	 * so its 'size' and 'csize' are equal.
2598 	 */
2599 	dumpbuf.vp_off = dumphdr->dump_ksyms = dumphdr->dump_start + PAGESIZE;
2600 	dumphdr->dump_ksyms_size = dumphdr->dump_ksyms_csize =
2601 	    ksyms_snapshot(dumpvp_ksyms_write, NULL, LONG_MAX);
2602 
2603 	/*
2604 	 * Write out the translation map.
2605 	 */
2606 	dumphdr->dump_map = dumpvp_flush();
2607 	dump_as(&kas);
2608 	dumphdr->dump_nvtop += dump_plat_addr();
2609 
2610 	/*
2611 	 * call into hat, which may have unmapped pages that also need to
2612 	 * be in the dump
2613 	 */
2614 	hat_dump();
2615 
2616 	if (dump_conflags & DUMP_ALL) {
2617 		mutex_enter(&pidlock);
2618 
2619 		for (npids = 0, p = practive; p != NULL; p = p->p_next)
2620 			dumpcfg.pids[npids++] = p->p_pid;
2621 
2622 		mutex_exit(&pidlock);
2623 
2624 		for (pidx = 0; pidx < npids; pidx++)
2625 			(void) dump_process(dumpcfg.pids[pidx]);
2626 
2627 		for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2628 			dump_timeleft = dump_timeout;
2629 			pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2630 			/*
2631 			 * Some hypervisors do not have all pages available to
2632 			 * be accessed by the guest OS.  Check for page
2633 			 * accessibility.
2634 			 */
2635 			if (plat_hold_page(pfn, PLAT_HOLD_NO_LOCK, NULL) !=
2636 			    PLAT_HOLD_OK)
2637 				continue;
2638 			BT_SET(dumpcfg.bitmap, bitnum);
2639 		}
2640 		dumphdr->dump_npages = dumpcfg.bitmapsize;
2641 		dumphdr->dump_flags |= DF_ALL;
2642 
2643 	} else if (dump_conflags & DUMP_CURPROC) {
2644 		/*
2645 		 * Determine which pid is to be dumped.  If we're panicking, we
2646 		 * dump the process associated with panic_thread (if any).  If
2647 		 * this is a live dump, we dump the process associated with
2648 		 * curthread.
2649 		 */
2650 		npids = 0;
2651 		if (panicstr) {
2652 			if (panic_thread != NULL &&
2653 			    panic_thread->t_procp != NULL &&
2654 			    panic_thread->t_procp != &p0) {
2655 				dumpcfg.pids[npids++] =
2656 				    panic_thread->t_procp->p_pid;
2657 			}
2658 		} else {
2659 			dumpcfg.pids[npids++] = curthread->t_procp->p_pid;
2660 		}
2661 
2662 		if (npids && dump_process(dumpcfg.pids[0]) == 0)
2663 			dumphdr->dump_flags |= DF_CURPROC;
2664 		else
2665 			dumphdr->dump_flags |= DF_KERNEL;
2666 
2667 	} else {
2668 		dumphdr->dump_flags |= DF_KERNEL;
2669 	}
2670 
2671 	dumphdr->dump_hashmask = (1 << highbit(dumphdr->dump_nvtop - 1)) - 1;
2672 
2673 	/*
2674 	 * Write out the pfn table.
2675 	 */
2676 	dumphdr->dump_pfn = dumpvp_flush();
2677 	dump_init_memlist_walker(&mlw);
2678 	for (bitnum = 0; bitnum < dumpcfg.bitmapsize; bitnum++) {
2679 		dump_timeleft = dump_timeout;
2680 		if (!BT_TEST(dumpcfg.bitmap, bitnum))
2681 			continue;
2682 		pfn = dump_bitnum_to_pfn(bitnum, &mlw);
2683 		ASSERT(pfn != PFN_INVALID);
2684 		dumpvp_write(&pfn, sizeof (pfn_t));
2685 	}
2686 	dump_plat_pfn();
2687 
2688 	/*
2689 	 * Write out all the pages.
2690 	 * Map pages, copy them handling UEs, compress, and write them out.
2691 	 * Cooperate with any helpers running on CPUs in panic_idle().
2692 	 */
2693 	dumphdr->dump_data = dumpvp_flush();
2694 
2695 	bzero(dumpcfg.helpermap, BT_SIZEOFMAP(NCPU));
2696 	ds->live = dumpcfg.clevel > 0 &&
2697 	    (dumphdr->dump_flags & DF_LIVE) != 0;
2698 
2699 	save_dump_clevel = dumpcfg.clevel;
2700 	if (panicstr)
2701 		dumpsys_get_maxmem();
2702 	else if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2703 		dumpcfg.clevel = DUMP_CLEVEL_LZJB;
2704 
2705 	dumpcfg.nhelper_used = 0;
2706 	for (hp = dumpcfg.helper; hp != hpend; hp++) {
2707 		if (hp->page == NULL) {
2708 			hp->helper = DONEHELPER;
2709 			continue;
2710 		}
2711 		++dumpcfg.nhelper_used;
2712 		hp->helper = FREEHELPER;
2713 		hp->taskqid = NULL;
2714 		hp->ds = ds;
2715 		bzero(&hp->perpage, sizeof (hp->perpage));
2716 		if (dumpcfg.clevel >= DUMP_CLEVEL_BZIP2)
2717 			(void) BZ2_bzCompressReset(&hp->bzstream);
2718 	}
2719 
2720 	CQ_OPEN(freebufq);
2721 	CQ_OPEN(helperq);
2722 
2723 	dumpcfg.ncbuf_used = 0;
2724 	for (cp = dumpcfg.cbuf; cp != &dumpcfg.cbuf[dumpcfg.ncbuf]; cp++) {
2725 		if (cp->buf != NULL) {
2726 			CQ_PUT(freebufq, cp, CBUF_FREEBUF);
2727 			++dumpcfg.ncbuf_used;
2728 		}
2729 	}
2730 
2731 	for (cp = dumpcfg.cmap; cp != &dumpcfg.cmap[dumpcfg.ncmap]; cp++)
2732 		CQ_PUT(mainq, cp, CBUF_FREEMAP);
2733 
2734 	ds->start = gethrtime();
2735 	ds->iowaitts = ds->start;
2736 
2737 	/* start helpers */
2738 	if (ds->live) {
2739 		int n = dumpcfg.nhelper_used;
2740 		int pri = MINCLSYSPRI - 25;
2741 
2742 		livetaskq = taskq_create("LiveDump", n, pri, n, n,
2743 		    TASKQ_PREPOPULATE);
2744 		for (hp = dumpcfg.helper; hp != hpend; hp++) {
2745 			if (hp->page == NULL)
2746 				continue;
2747 			hp->helper = hp - dumpcfg.helper;
2748 			hp->taskqid = taskq_dispatch(livetaskq,
2749 			    dumpsys_live_helper, (void *)hp, TQ_NOSLEEP);
2750 		}
2751 
2752 	} else {
2753 		if (panicstr)
2754 			kmem_dump_begin();
2755 		dumpcfg.helpers_wanted = dumpcfg.clevel > 0;
2756 		dumpsys_spinunlock(&dumpcfg.helper_lock);
2757 	}
2758 
2759 	/* run main task */
2760 	dumpsys_main_task(ds);
2761 
2762 	ds->elapsed = gethrtime() - ds->start;
2763 	if (ds->elapsed < 1)
2764 		ds->elapsed = 1;
2765 
2766 	if (livetaskq != NULL)
2767 		taskq_destroy(livetaskq);
2768 
2769 	if (ds->neednl) {
2770 		uprintf("\n");
2771 		ds->neednl = 0;
2772 	}
2773 
2774 	/* record actual pages dumped */
2775 	dumphdr->dump_npages = ds->npages;
2776 
2777 	/* platform-specific data */
2778 	dumphdr->dump_npages += dump_plat_data(dumpcfg.cbuf[0].buf);
2779 
2780 	/* note any errors by clearing DF_COMPLETE */
2781 	if (dump_ioerr || ds->npages < dumphdr->dump_npages)
2782 		dumphdr->dump_flags &= ~DF_COMPLETE;
2783 
2784 	/* end of stream blocks */
2785 	datatag = 0;
2786 	dumpvp_write(&datatag, sizeof (datatag));
2787 
2788 	bzero(&datahdr, sizeof (datahdr));
2789 
2790 	/* buffer for metrics */
2791 	buf = dumpcfg.cbuf[0].buf;
2792 	size = MIN(dumpcfg.cbuf[0].size, DUMP_OFFSET - sizeof (dumphdr_t) -
2793 	    sizeof (dumpdatahdr_t));
2794 
2795 	/* finish the kmem intercepts, collect kmem verbose info */
2796 	if (panicstr) {
2797 		datahdr.dump_metrics = kmem_dump_finish(buf, size);
2798 		buf += datahdr.dump_metrics;
2799 		size -= datahdr.dump_metrics;
2800 	}
2801 
2802 	/* compression info in data header */
2803 	datahdr.dump_datahdr_magic = DUMP_DATAHDR_MAGIC;
2804 	datahdr.dump_datahdr_version = DUMP_DATAHDR_VERSION;
2805 	datahdr.dump_maxcsize = CBUF_SIZE;
2806 	datahdr.dump_maxrange = CBUF_MAPSIZE / PAGESIZE;
2807 	datahdr.dump_nstreams = dumpcfg.nhelper_used;
2808 	datahdr.dump_clevel = dumpcfg.clevel;
2809 #ifdef COLLECT_METRICS
2810 	if (dump_metrics_on)
2811 		datahdr.dump_metrics += dumpsys_metrics(ds, buf, size);
2812 #endif
2813 	datahdr.dump_data_csize = dumpvp_flush() - dumphdr->dump_data;
2814 
2815 	/*
2816 	 * Write out the initial and terminal dump headers.
2817 	 */
2818 	dumpbuf.vp_off = dumphdr->dump_start;
2819 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
2820 	(void) dumpvp_flush();
2821 
2822 	dumpbuf.vp_limit = dumpvp_size;
2823 	dumpbuf.vp_off = dumpbuf.vp_limit - DUMP_OFFSET;
2824 	dumpvp_write(dumphdr, sizeof (dumphdr_t));
2825 	dumpvp_write(&datahdr, sizeof (dumpdatahdr_t));
2826 	dumpvp_write(dumpcfg.cbuf[0].buf, datahdr.dump_metrics);
2827 
2828 	(void) dumpvp_flush();
2829 
2830 	uprintf("\r%3d%% done: %llu pages dumped, ",
2831 	    ds->percent_done, (u_longlong_t)ds->npages);
2832 
2833 	if (dump_ioerr == 0) {
2834 		uprintf("dump succeeded\n");
2835 	} else {
2836 		uprintf("dump failed: error %d\n", dump_ioerr);
2837 #ifdef DEBUG
2838 		if (panicstr)
2839 			debug_enter("dump failed");
2840 #endif
2841 	}
2842 
2843 	/*
2844 	 * Write out all undelivered messages.  This has to be the *last*
2845 	 * thing we do because the dump process itself emits messages.
2846 	 */
2847 	if (panicstr) {
2848 		dump_ereports();
2849 		dump_messages();
2850 	}
2851 
2852 	delay(2 * hz);	/* let people see the 'done' message */
2853 	dump_timeleft = 0;
2854 	dump_ioerr = 0;
2855 
2856 	/* restore settings after live dump completes */
2857 	if (!panicstr) {
2858 		dumpcfg.clevel = save_dump_clevel;
2859 
2860 		/* release any VCHR open of the dump device */
2861 		if (dumpbuf.cdev_vp != NULL) {
2862 			(void) VOP_CLOSE(dumpbuf.cdev_vp, FREAD | FWRITE, 1, 0,
2863 			    kcred, NULL);
2864 			VN_RELE(dumpbuf.cdev_vp);
2865 			dumpbuf.cdev_vp = NULL;
2866 		}
2867 	}
2868 }
2869 
2870 /*
2871  * This function is called whenever the memory size, as represented
2872  * by the phys_install list, changes.
2873  */
2874 void
2875 dump_resize()
2876 {
2877 	mutex_enter(&dump_lock);
2878 	dumphdr_init();
2879 	dumpbuf_resize();
2880 	dump_update_clevel();
2881 	mutex_exit(&dump_lock);
2882 }
2883 
2884 /*
2885  * This function allows for dynamic resizing of a dump area. It assumes that
2886  * the underlying device has update its appropriate size(9P).
2887  */
2888 int
2889 dumpvp_resize()
2890 {
2891 	int error;
2892 	vattr_t vattr;
2893 
2894 	mutex_enter(&dump_lock);
2895 	vattr.va_mask = AT_SIZE;
2896 	if ((error = VOP_GETATTR(dumpvp, &vattr, 0, kcred, NULL)) != 0) {
2897 		mutex_exit(&dump_lock);
2898 		return (error);
2899 	}
2900 
2901 	if (error == 0 && vattr.va_size < 2 * DUMP_LOGSIZE + DUMP_ERPTSIZE) {
2902 		mutex_exit(&dump_lock);
2903 		return (ENOSPC);
2904 	}
2905 
2906 	dumpvp_size = vattr.va_size & -DUMP_OFFSET;
2907 	mutex_exit(&dump_lock);
2908 	return (0);
2909 }
2910