FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_pcpu.c
1 /*-
2 * Copyright (c) 2001 Wind River Systems, Inc.
3 * All rights reserved.
4 * Written by: John Baldwin <jhb@FreeBSD.org>
5 *
6 * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the author nor the names of any co-contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 /*
35 * This module provides MI support for per-cpu data.
36 *
37 * Each architecture determines the mapping of logical CPU IDs to physical
38 * CPUs. The requirements of this mapping are as follows:
39 * - Logical CPU IDs must reside in the range 0 ... MAXCPU - 1.
40 * - The mapping is not required to be dense. That is, there may be
41 * gaps in the mappings.
42 * - The platform sets the value of MAXCPU in <machine/param.h>.
43 * - It is suggested, but not required, that in the non-SMP case, the
44 * platform define MAXCPU to be 1 and define the logical ID of the
45 * sole CPU as 0.
46 */
47
48 #include <sys/cdefs.h>
49 __FBSDID("$FreeBSD: releng/10.0/sys/kern/subr_pcpu.c 227293 2011-11-07 06:44:47Z ed $");
50
51 #include "opt_ddb.h"
52
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/sysctl.h>
56 #include <sys/lock.h>
57 #include <sys/malloc.h>
58 #include <sys/pcpu.h>
59 #include <sys/proc.h>
60 #include <sys/smp.h>
61 #include <sys/sx.h>
62 #include <ddb/ddb.h>
63
64 static MALLOC_DEFINE(M_PCPU, "Per-cpu", "Per-cpu resource accouting.");
65
66 struct dpcpu_free {
67 uintptr_t df_start;
68 int df_len;
69 TAILQ_ENTRY(dpcpu_free) df_link;
70 };
71
72 static DPCPU_DEFINE(char, modspace[DPCPU_MODMIN]);
73 static TAILQ_HEAD(, dpcpu_free) dpcpu_head = TAILQ_HEAD_INITIALIZER(dpcpu_head);
74 static struct sx dpcpu_lock;
75 uintptr_t dpcpu_off[MAXCPU];
76 struct pcpu *cpuid_to_pcpu[MAXCPU];
77 struct cpuhead cpuhead = STAILQ_HEAD_INITIALIZER(cpuhead);
78
79 /*
80 * Initialize the MI portions of a struct pcpu.
81 */
82 void
83 pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
84 {
85
86 bzero(pcpu, size);
87 KASSERT(cpuid >= 0 && cpuid < MAXCPU,
88 ("pcpu_init: invalid cpuid %d", cpuid));
89 pcpu->pc_cpuid = cpuid;
90 cpuid_to_pcpu[cpuid] = pcpu;
91 STAILQ_INSERT_TAIL(&cpuhead, pcpu, pc_allcpu);
92 cpu_pcpu_init(pcpu, cpuid, size);
93 pcpu->pc_rm_queue.rmq_next = &pcpu->pc_rm_queue;
94 pcpu->pc_rm_queue.rmq_prev = &pcpu->pc_rm_queue;
95 }
96
97 void
98 dpcpu_init(void *dpcpu, int cpuid)
99 {
100 struct pcpu *pcpu;
101
102 pcpu = pcpu_find(cpuid);
103 pcpu->pc_dynamic = (uintptr_t)dpcpu - DPCPU_START;
104
105 /*
106 * Initialize defaults from our linker section.
107 */
108 memcpy(dpcpu, (void *)DPCPU_START, DPCPU_BYTES);
109
110 /*
111 * Place it in the global pcpu offset array.
112 */
113 dpcpu_off[cpuid] = pcpu->pc_dynamic;
114 }
115
116 static void
117 dpcpu_startup(void *dummy __unused)
118 {
119 struct dpcpu_free *df;
120
121 df = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
122 df->df_start = (uintptr_t)&DPCPU_NAME(modspace);
123 df->df_len = DPCPU_MODMIN;
124 TAILQ_INSERT_HEAD(&dpcpu_head, df, df_link);
125 sx_init(&dpcpu_lock, "dpcpu alloc lock");
126 }
127 SYSINIT(dpcpu, SI_SUB_KLD, SI_ORDER_FIRST, dpcpu_startup, 0);
128
129 /*
130 * First-fit extent based allocator for allocating space in the per-cpu
131 * region reserved for modules. This is only intended for use by the
132 * kernel linkers to place module linker sets.
133 */
134 void *
135 dpcpu_alloc(int size)
136 {
137 struct dpcpu_free *df;
138 void *s;
139
140 s = NULL;
141 size = roundup2(size, sizeof(void *));
142 sx_xlock(&dpcpu_lock);
143 TAILQ_FOREACH(df, &dpcpu_head, df_link) {
144 if (df->df_len < size)
145 continue;
146 if (df->df_len == size) {
147 s = (void *)df->df_start;
148 TAILQ_REMOVE(&dpcpu_head, df, df_link);
149 free(df, M_PCPU);
150 break;
151 }
152 s = (void *)df->df_start;
153 df->df_len -= size;
154 df->df_start = df->df_start + size;
155 break;
156 }
157 sx_xunlock(&dpcpu_lock);
158
159 return (s);
160 }
161
162 /*
163 * Free dynamic per-cpu space at module unload time.
164 */
165 void
166 dpcpu_free(void *s, int size)
167 {
168 struct dpcpu_free *df;
169 struct dpcpu_free *dn;
170 uintptr_t start;
171 uintptr_t end;
172
173 size = roundup2(size, sizeof(void *));
174 start = (uintptr_t)s;
175 end = start + size;
176 /*
177 * Free a region of space and merge it with as many neighbors as
178 * possible. Keeping the list sorted simplifies this operation.
179 */
180 sx_xlock(&dpcpu_lock);
181 TAILQ_FOREACH(df, &dpcpu_head, df_link) {
182 if (df->df_start > end)
183 break;
184 /*
185 * If we expand at the end of an entry we may have to
186 * merge it with the one following it as well.
187 */
188 if (df->df_start + df->df_len == start) {
189 df->df_len += size;
190 dn = TAILQ_NEXT(df, df_link);
191 if (df->df_start + df->df_len == dn->df_start) {
192 df->df_len += dn->df_len;
193 TAILQ_REMOVE(&dpcpu_head, dn, df_link);
194 free(dn, M_PCPU);
195 }
196 sx_xunlock(&dpcpu_lock);
197 return;
198 }
199 if (df->df_start == end) {
200 df->df_start = start;
201 df->df_len += size;
202 sx_xunlock(&dpcpu_lock);
203 return;
204 }
205 }
206 dn = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
207 dn->df_start = start;
208 dn->df_len = size;
209 if (df)
210 TAILQ_INSERT_BEFORE(df, dn, df_link);
211 else
212 TAILQ_INSERT_TAIL(&dpcpu_head, dn, df_link);
213 sx_xunlock(&dpcpu_lock);
214 }
215
216 /*
217 * Initialize the per-cpu storage from an updated linker-set region.
218 */
219 void
220 dpcpu_copy(void *s, int size)
221 {
222 #ifdef SMP
223 uintptr_t dpcpu;
224 int i;
225
226 for (i = 0; i < mp_ncpus; ++i) {
227 dpcpu = dpcpu_off[i];
228 if (dpcpu == 0)
229 continue;
230 memcpy((void *)(dpcpu + (uintptr_t)s), s, size);
231 }
232 #else
233 memcpy((void *)(dpcpu_off[0] + (uintptr_t)s), s, size);
234 #endif
235 }
236
237 /*
238 * Destroy a struct pcpu.
239 */
240 void
241 pcpu_destroy(struct pcpu *pcpu)
242 {
243
244 STAILQ_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
245 cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
246 dpcpu_off[pcpu->pc_cpuid] = 0;
247 }
248
249 /*
250 * Locate a struct pcpu by cpu id.
251 */
252 struct pcpu *
253 pcpu_find(u_int cpuid)
254 {
255
256 return (cpuid_to_pcpu[cpuid]);
257 }
258
259 int
260 sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS)
261 {
262 uintptr_t dpcpu;
263 int64_t count;
264 int i;
265
266 count = 0;
267 for (i = 0; i < mp_ncpus; ++i) {
268 dpcpu = dpcpu_off[i];
269 if (dpcpu == 0)
270 continue;
271 count += *(int64_t *)(dpcpu + (uintptr_t)arg1);
272 }
273 return (SYSCTL_OUT(req, &count, sizeof(count)));
274 }
275
276 int
277 sysctl_dpcpu_long(SYSCTL_HANDLER_ARGS)
278 {
279 uintptr_t dpcpu;
280 long count;
281 int i;
282
283 count = 0;
284 for (i = 0; i < mp_ncpus; ++i) {
285 dpcpu = dpcpu_off[i];
286 if (dpcpu == 0)
287 continue;
288 count += *(long *)(dpcpu + (uintptr_t)arg1);
289 }
290 return (SYSCTL_OUT(req, &count, sizeof(count)));
291 }
292
293 int
294 sysctl_dpcpu_int(SYSCTL_HANDLER_ARGS)
295 {
296 uintptr_t dpcpu;
297 int count;
298 int i;
299
300 count = 0;
301 for (i = 0; i < mp_ncpus; ++i) {
302 dpcpu = dpcpu_off[i];
303 if (dpcpu == 0)
304 continue;
305 count += *(int *)(dpcpu + (uintptr_t)arg1);
306 }
307 return (SYSCTL_OUT(req, &count, sizeof(count)));
308 }
309
310 #ifdef DDB
311 DB_SHOW_COMMAND(dpcpu_off, db_show_dpcpu_off)
312 {
313 int id;
314
315 CPU_FOREACH(id) {
316 db_printf("dpcpu_off[%2d] = 0x%jx (+ DPCPU_START = %p)\n",
317 id, (uintmax_t)dpcpu_off[id],
318 (void *)(uintptr_t)(dpcpu_off[id] + DPCPU_START));
319 }
320 }
321
322 static void
323 show_pcpu(struct pcpu *pc)
324 {
325 struct thread *td;
326
327 db_printf("cpuid = %d\n", pc->pc_cpuid);
328 db_printf("dynamic pcpu = %p\n", (void *)pc->pc_dynamic);
329 db_printf("curthread = ");
330 td = pc->pc_curthread;
331 if (td != NULL)
332 db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
333 td->td_name);
334 else
335 db_printf("none\n");
336 db_printf("curpcb = %p\n", pc->pc_curpcb);
337 db_printf("fpcurthread = ");
338 td = pc->pc_fpcurthread;
339 if (td != NULL)
340 db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
341 td->td_name);
342 else
343 db_printf("none\n");
344 db_printf("idlethread = ");
345 td = pc->pc_idlethread;
346 if (td != NULL)
347 db_printf("%p: tid %d \"%s\"\n", td, td->td_tid, td->td_name);
348 else
349 db_printf("none\n");
350 db_show_mdpcpu(pc);
351
352 #ifdef VIMAGE
353 db_printf("curvnet = %p\n", pc->pc_curthread->td_vnet);
354 #endif
355
356 #ifdef WITNESS
357 db_printf("spin locks held:\n");
358 witness_list_locks(&pc->pc_spinlocks, db_printf);
359 #endif
360 }
361
362 DB_SHOW_COMMAND(pcpu, db_show_pcpu)
363 {
364 struct pcpu *pc;
365 int id;
366
367 if (have_addr)
368 id = ((addr >> 4) % 16) * 10 + (addr % 16);
369 else
370 id = PCPU_GET(cpuid);
371 pc = pcpu_find(id);
372 if (pc == NULL) {
373 db_printf("CPU %d not found\n", id);
374 return;
375 }
376 show_pcpu(pc);
377 }
378
379 DB_SHOW_ALL_COMMAND(pcpu, db_show_cpu_all)
380 {
381 struct pcpu *pc;
382 int id;
383
384 db_printf("Current CPU: %d\n\n", PCPU_GET(cpuid));
385 for (id = 0; id <= mp_maxid; id++) {
386 pc = pcpu_find(id);
387 if (pc != NULL) {
388 show_pcpu(pc);
389 db_printf("\n");
390 }
391 }
392 }
393 DB_SHOW_ALIAS(allpcpu, db_show_cpu_all);
394 #endif
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