summaryrefslogtreecommitdiffstats
path: root/lib/libkvm/kvm_pcpu.c
blob: 662566adba71376618b54dc769496a5886a170d2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
/*-
 * Copyright (c) 2013 Gleb Smirnoff <glebius@FreeBSD.org>
 * Copyright (c) 2010 Juniper Networks, Inc.
 * Copyright (c) 2009 Robert N. M. Watson
 * Copyright (c) 2009 Bjoern A. Zeeb <bz@FreeBSD.org>
 * Copyright (c) 2008 Yahoo!, Inc.
 * All rights reserved.
 *
 * Written by: John Baldwin <jhb@FreeBSD.org>
 *
 * This software was developed by Robert N. M. Watson under contract
 * to Juniper Networks, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/pcpu.h>
#include <sys/sysctl.h>
#include <kvm.h>
#include <limits.h>
#include <stdlib.h>

#include "kvm_private.h"

static struct nlist kvm_pcpu_nl[] = {
	{ .n_name = "_cpuid_to_pcpu" },
	{ .n_name = "_mp_maxcpus" },
	{ .n_name = "_mp_ncpus" },
	{ .n_name = NULL },
};
#define	NL_CPUID_TO_PCPU	0
#define	NL_MP_MAXCPUS		1
#define	NL_MP_NCPUS		2

/*
 * Kernel per-CPU data state.  We cache this stuff on the first
 * access.	
 *
 * XXXRW: Possibly, this (and kvmpcpu_nl) should be per-kvm_t, in case the
 * consumer has multiple handles in flight to differently configured
 * kernels/crashdumps.
 */
static void **pcpu_data;
static int maxcpu;
static int mp_ncpus;

static int
_kvm_pcpu_init(kvm_t *kd)
{
	size_t len;
	int max;
	void *data;

	if (kvm_nlist(kd, kvm_pcpu_nl) < 0)
		return (-1);
	if (kvm_pcpu_nl[NL_CPUID_TO_PCPU].n_value == 0) {
		_kvm_err(kd, kd->program, "unable to find cpuid_to_pcpu");
		return (-1);
	}
	if (kvm_pcpu_nl[NL_MP_MAXCPUS].n_value == 0) {
		_kvm_err(kd, kd->program, "unable to find mp_maxcpus");
		return (-1);
	}
	if (kvm_read(kd, kvm_pcpu_nl[NL_MP_MAXCPUS].n_value, &max,
	    sizeof(max)) != sizeof(max)) {
		_kvm_err(kd, kd->program, "cannot read mp_maxcpus");
		return (-1);
	}
	if (kvm_pcpu_nl[NL_MP_NCPUS].n_value == 0) {
		_kvm_err(kd, kd->program, "unable to find mp_ncpus");
		return (-1);
	}
	if (kvm_read(kd, kvm_pcpu_nl[NL_MP_NCPUS].n_value, &mp_ncpus,
	    sizeof(mp_ncpus)) != sizeof(mp_ncpus)) {
		_kvm_err(kd, kd->program, "cannot read mp_ncpus");
		return (-1);
	}
	len = max * sizeof(void *);
	data = malloc(len);
	if (data == NULL) {
		_kvm_err(kd, kd->program, "out of memory");
		return (-1);
	}
	if (kvm_read(kd, kvm_pcpu_nl[NL_CPUID_TO_PCPU].n_value, data, len) !=
	   (ssize_t)len) {
		_kvm_err(kd, kd->program, "cannot read cpuid_to_pcpu array");
		free(data);
		return (-1);
	}
	pcpu_data = data;
	maxcpu = max;
	return (0);
}

static void
_kvm_pcpu_clear(void)
{

	maxcpu = 0;
	free(pcpu_data);
	pcpu_data = NULL;
}

void *
kvm_getpcpu(kvm_t *kd, int cpu)
{
	char *buf;

	if (kd == NULL) {
		_kvm_pcpu_clear();
		return (NULL);
	}

	if (maxcpu == 0)
		if (_kvm_pcpu_init(kd) < 0)
			return ((void *)-1);

	if (cpu >= maxcpu || pcpu_data[cpu] == NULL)
		return (NULL);

	buf = malloc(sizeof(struct pcpu));
	if (buf == NULL) {
		_kvm_err(kd, kd->program, "out of memory");
		return ((void *)-1);
	}
	if (kvm_read(kd, (uintptr_t)pcpu_data[cpu], buf,
	    sizeof(struct pcpu)) != sizeof(struct pcpu)) {
		_kvm_err(kd, kd->program, "unable to read per-CPU data");
		free(buf);
		return ((void *)-1);
	}
	return (buf);
}

int
kvm_getmaxcpu(kvm_t *kd)
{

	if (kd == NULL) {
		_kvm_pcpu_clear();
		return (0);
	}

	if (maxcpu == 0)
		if (_kvm_pcpu_init(kd) < 0)
			return (-1);
	return (maxcpu);
}

int
kvm_getncpus(kvm_t *kd)
{

	if (mp_ncpus == 0)
		if (_kvm_pcpu_init(kd) < 0)
			return (-1);
	return (mp_ncpus);
}

static int
_kvm_dpcpu_setcpu(kvm_t *kd, u_int cpu, int report_error)
{

	if (!kd->dpcpu_initialized) {
		if (report_error)
			_kvm_err(kd, kd->program, "%s: not initialized",
			    __func__);
		return (-1);
	}
	if (cpu >= kd->dpcpu_maxcpus) {
		if (report_error)
			_kvm_err(kd, kd->program, "%s: CPU %u too big",
			    __func__, cpu);
		return (-1);
	}
	if (kd->dpcpu_off[cpu] == 0) {
		if (report_error)
			_kvm_err(kd, kd->program, "%s: CPU %u not found",
			    __func__, cpu);
		return (-1);
	}
	kd->dpcpu_curcpu = cpu;
	kd->dpcpu_curoff = kd->dpcpu_off[cpu];
	return (0);
}

/*
 * Set up libkvm to handle dynamic per-CPU memory.
 */
static int
_kvm_dpcpu_init(kvm_t *kd)
{
	struct nlist nl[] = {
#define	NLIST_START_SET_PCPU	0
		{ .n_name = "___start_" DPCPU_SETNAME },
#define	NLIST_STOP_SET_PCPU	1
		{ .n_name = "___stop_" DPCPU_SETNAME },
#define	NLIST_DPCPU_OFF		2
		{ .n_name = "_dpcpu_off" },
#define	NLIST_MP_MAXCPUS	3
		{ .n_name = "_mp_maxcpus" },
		{ .n_name = NULL },
	};
	uintptr_t *dpcpu_off_buf;
	size_t len;
	u_int dpcpu_maxcpus;

	/*
	 * Locate and cache locations of important symbols using the internal
	 * version of _kvm_nlist, turning off initialization to avoid
	 * recursion in case of unresolveable symbols.
	 */
	if (_kvm_nlist(kd, nl, 0) != 0)
		return (-1);
	if (kvm_read(kd, nl[NLIST_MP_MAXCPUS].n_value, &dpcpu_maxcpus,
	    sizeof(dpcpu_maxcpus)) != sizeof(dpcpu_maxcpus))
		return (-1);
	len = dpcpu_maxcpus * sizeof(*dpcpu_off_buf);
	dpcpu_off_buf = malloc(len);
	if (dpcpu_off_buf == NULL)
		return (-1);
	if (kvm_read(kd, nl[NLIST_DPCPU_OFF].n_value, dpcpu_off_buf, len) !=
	    (ssize_t)len) {
		free(dpcpu_off_buf);
		return (-1);
	}
	kd->dpcpu_start = nl[NLIST_START_SET_PCPU].n_value;
	kd->dpcpu_stop = nl[NLIST_STOP_SET_PCPU].n_value;
	kd->dpcpu_maxcpus = dpcpu_maxcpus;
	kd->dpcpu_off = dpcpu_off_buf;
	kd->dpcpu_initialized = 1;
	(void)_kvm_dpcpu_setcpu(kd, 0, 0);
	return (0);
}

/*
 * Check whether the dpcpu module has been initialized sucessfully or not,
 * initialize it if permitted.
 */
int
_kvm_dpcpu_initialized(kvm_t *kd, int intialize)
{

	if (kd->dpcpu_initialized || !intialize)
		return (kd->dpcpu_initialized);

	(void)_kvm_dpcpu_init(kd);

	return (kd->dpcpu_initialized);
}

/*
 * Check whether the value is within the dpcpu symbol range and only if so
 * adjust the offset relative to the current offset.
 */
uintptr_t
_kvm_dpcpu_validaddr(kvm_t *kd, uintptr_t value)
{

	if (value == 0)
		return (value);

	if (!kd->dpcpu_initialized)
		return (value);

	if (value < kd->dpcpu_start || value >= kd->dpcpu_stop)
		return (value);

	return (kd->dpcpu_curoff + value);
}

int
kvm_dpcpu_setcpu(kvm_t *kd, u_int cpu)
{
	int ret;

	if (!kd->dpcpu_initialized) {
		ret = _kvm_dpcpu_init(kd);
		if (ret != 0) {
			_kvm_err(kd, kd->program, "%s: init failed",
			    __func__);
			return (ret);
		}
	}

	return (_kvm_dpcpu_setcpu(kd, cpu, 1));
}

/*
 * Obtain a per-CPU copy for given cpu from UMA_ZONE_PCPU allocation.
 */
ssize_t
kvm_read_zpcpu(kvm_t *kd, u_long base, void *buf, size_t size, int cpu)
{

	return (kvm_read(kd, (uintptr_t)(base + sizeof(struct pcpu) * cpu),
	    buf, size));
}

/*
 * Fetch value of a counter(9).
 */
uint64_t
kvm_counter_u64_fetch(kvm_t *kd, u_long base)
{
	uint64_t r, c;

	if (mp_ncpus == 0)
		if (_kvm_pcpu_init(kd) < 0)
			return (0);

	r = 0;
	for (int i = 0; i < mp_ncpus; i++) {
		if (kvm_read_zpcpu(kd, base, &c, sizeof(c), i) != sizeof(c))
			return (0);
		r += c;
	}

	return (r);
}
OpenPOWER on IntegriCloud