FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_pcpu.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2001 Wind River Systems, Inc.
5 * All rights reserved.
6 * Written by: John Baldwin <jhb@FreeBSD.org>
7 *
8 * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the author nor the names of any co-contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 /*
37 * This module provides MI support for per-cpu data.
38 *
39 * Each architecture determines the mapping of logical CPU IDs to physical
40 * CPUs. The requirements of this mapping are as follows:
41 * - Logical CPU IDs must reside in the range 0 ... MAXCPU - 1.
42 * - The mapping is not required to be dense. That is, there may be
43 * gaps in the mappings.
44 * - The platform sets the value of MAXCPU in <machine/param.h>.
45 * - It is suggested, but not required, that in the non-SMP case, the
46 * platform define MAXCPU to be 1 and define the logical ID of the
47 * sole CPU as 0.
48 */
49
50 #include <sys/cdefs.h>
51 __FBSDID("$FreeBSD: releng/12.0/sys/kern/subr_pcpu.c 336906 2018-07-30 14:25:17Z andrew $");
52
53 #include "opt_ddb.h"
54
55 #include <sys/param.h>
56 #include <sys/systm.h>
57 #include <sys/sysctl.h>
58 #include <sys/lock.h>
59 #include <sys/malloc.h>
60 #include <sys/pcpu.h>
61 #include <sys/proc.h>
62 #include <sys/smp.h>
63 #include <sys/sx.h>
64 #include <vm/uma.h>
65 #include <ddb/ddb.h>
66
67 static MALLOC_DEFINE(M_PCPU, "Per-cpu", "Per-cpu resource accouting.");
68
69 struct dpcpu_free {
70 uintptr_t df_start;
71 int df_len;
72 TAILQ_ENTRY(dpcpu_free) df_link;
73 };
74
75 DPCPU_DEFINE_STATIC(char, modspace[DPCPU_MODMIN] __aligned(__alignof(void *)));
76 static TAILQ_HEAD(, dpcpu_free) dpcpu_head = TAILQ_HEAD_INITIALIZER(dpcpu_head);
77 static struct sx dpcpu_lock;
78 uintptr_t dpcpu_off[MAXCPU];
79 struct pcpu *cpuid_to_pcpu[MAXCPU];
80 struct cpuhead cpuhead = STAILQ_HEAD_INITIALIZER(cpuhead);
81
82 /*
83 * Initialize the MI portions of a struct pcpu.
84 */
85 void
86 pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
87 {
88
89 bzero(pcpu, size);
90 KASSERT(cpuid >= 0 && cpuid < MAXCPU,
91 ("pcpu_init: invalid cpuid %d", cpuid));
92 pcpu->pc_cpuid = cpuid;
93 cpuid_to_pcpu[cpuid] = pcpu;
94 STAILQ_INSERT_TAIL(&cpuhead, pcpu, pc_allcpu);
95 cpu_pcpu_init(pcpu, cpuid, size);
96 pcpu->pc_rm_queue.rmq_next = &pcpu->pc_rm_queue;
97 pcpu->pc_rm_queue.rmq_prev = &pcpu->pc_rm_queue;
98 }
99
100 void
101 dpcpu_init(void *dpcpu, int cpuid)
102 {
103 struct pcpu *pcpu;
104
105 pcpu = pcpu_find(cpuid);
106 pcpu->pc_dynamic = (uintptr_t)dpcpu - DPCPU_START;
107
108 /*
109 * Initialize defaults from our linker section.
110 */
111 memcpy(dpcpu, (void *)DPCPU_START, DPCPU_BYTES);
112
113 /*
114 * Place it in the global pcpu offset array.
115 */
116 dpcpu_off[cpuid] = pcpu->pc_dynamic;
117 }
118
119 static void
120 dpcpu_startup(void *dummy __unused)
121 {
122 struct dpcpu_free *df;
123
124 df = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
125 df->df_start = (uintptr_t)&DPCPU_NAME(modspace);
126 df->df_len = DPCPU_MODMIN;
127 TAILQ_INSERT_HEAD(&dpcpu_head, df, df_link);
128 sx_init(&dpcpu_lock, "dpcpu alloc lock");
129 }
130 SYSINIT(dpcpu, SI_SUB_KLD, SI_ORDER_FIRST, dpcpu_startup, NULL);
131
132 /*
133 * UMA_PCPU_ZONE zones, that are available for all kernel
134 * consumers. Right now 64 bit zone is used for counter(9)
135 * and pointer zone is used by flowtable.
136 */
137
138 uma_zone_t pcpu_zone_64;
139 uma_zone_t pcpu_zone_ptr;
140
141 static void
142 pcpu_zones_startup(void)
143 {
144
145 pcpu_zone_64 = uma_zcreate("64 pcpu", sizeof(uint64_t),
146 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
147
148 if (sizeof(uint64_t) == sizeof(void *))
149 pcpu_zone_ptr = pcpu_zone_64;
150 else
151 pcpu_zone_ptr = uma_zcreate("ptr pcpu", sizeof(void *),
152 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
153 }
154 SYSINIT(pcpu_zones, SI_SUB_VM, SI_ORDER_ANY, pcpu_zones_startup, NULL);
155
156 /*
157 * First-fit extent based allocator for allocating space in the per-cpu
158 * region reserved for modules. This is only intended for use by the
159 * kernel linkers to place module linker sets.
160 */
161 void *
162 dpcpu_alloc(int size)
163 {
164 struct dpcpu_free *df;
165 void *s;
166
167 s = NULL;
168 size = roundup2(size, sizeof(void *));
169 sx_xlock(&dpcpu_lock);
170 TAILQ_FOREACH(df, &dpcpu_head, df_link) {
171 if (df->df_len < size)
172 continue;
173 if (df->df_len == size) {
174 s = (void *)df->df_start;
175 TAILQ_REMOVE(&dpcpu_head, df, df_link);
176 free(df, M_PCPU);
177 break;
178 }
179 s = (void *)df->df_start;
180 df->df_len -= size;
181 df->df_start = df->df_start + size;
182 break;
183 }
184 sx_xunlock(&dpcpu_lock);
185
186 return (s);
187 }
188
189 /*
190 * Free dynamic per-cpu space at module unload time.
191 */
192 void
193 dpcpu_free(void *s, int size)
194 {
195 struct dpcpu_free *df;
196 struct dpcpu_free *dn;
197 uintptr_t start;
198 uintptr_t end;
199
200 size = roundup2(size, sizeof(void *));
201 start = (uintptr_t)s;
202 end = start + size;
203 /*
204 * Free a region of space and merge it with as many neighbors as
205 * possible. Keeping the list sorted simplifies this operation.
206 */
207 sx_xlock(&dpcpu_lock);
208 TAILQ_FOREACH(df, &dpcpu_head, df_link) {
209 if (df->df_start > end)
210 break;
211 /*
212 * If we expand at the end of an entry we may have to
213 * merge it with the one following it as well.
214 */
215 if (df->df_start + df->df_len == start) {
216 df->df_len += size;
217 dn = TAILQ_NEXT(df, df_link);
218 if (df->df_start + df->df_len == dn->df_start) {
219 df->df_len += dn->df_len;
220 TAILQ_REMOVE(&dpcpu_head, dn, df_link);
221 free(dn, M_PCPU);
222 }
223 sx_xunlock(&dpcpu_lock);
224 return;
225 }
226 if (df->df_start == end) {
227 df->df_start = start;
228 df->df_len += size;
229 sx_xunlock(&dpcpu_lock);
230 return;
231 }
232 }
233 dn = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
234 dn->df_start = start;
235 dn->df_len = size;
236 if (df)
237 TAILQ_INSERT_BEFORE(df, dn, df_link);
238 else
239 TAILQ_INSERT_TAIL(&dpcpu_head, dn, df_link);
240 sx_xunlock(&dpcpu_lock);
241 }
242
243 /*
244 * Initialize the per-cpu storage from an updated linker-set region.
245 */
246 void
247 dpcpu_copy(void *s, int size)
248 {
249 #ifdef SMP
250 uintptr_t dpcpu;
251 int i;
252
253 CPU_FOREACH(i) {
254 dpcpu = dpcpu_off[i];
255 if (dpcpu == 0)
256 continue;
257 memcpy((void *)(dpcpu + (uintptr_t)s), s, size);
258 }
259 #else
260 memcpy((void *)(dpcpu_off[0] + (uintptr_t)s), s, size);
261 #endif
262 }
263
264 /*
265 * Destroy a struct pcpu.
266 */
267 void
268 pcpu_destroy(struct pcpu *pcpu)
269 {
270
271 STAILQ_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
272 cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
273 dpcpu_off[pcpu->pc_cpuid] = 0;
274 }
275
276 /*
277 * Locate a struct pcpu by cpu id.
278 */
279 struct pcpu *
280 pcpu_find(u_int cpuid)
281 {
282
283 return (cpuid_to_pcpu[cpuid]);
284 }
285
286 int
287 sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS)
288 {
289 uintptr_t dpcpu;
290 int64_t count;
291 int i;
292
293 count = 0;
294 CPU_FOREACH(i) {
295 dpcpu = dpcpu_off[i];
296 if (dpcpu == 0)
297 continue;
298 count += *(int64_t *)(dpcpu + (uintptr_t)arg1);
299 }
300 return (SYSCTL_OUT(req, &count, sizeof(count)));
301 }
302
303 int
304 sysctl_dpcpu_long(SYSCTL_HANDLER_ARGS)
305 {
306 uintptr_t dpcpu;
307 long count;
308 int i;
309
310 count = 0;
311 CPU_FOREACH(i) {
312 dpcpu = dpcpu_off[i];
313 if (dpcpu == 0)
314 continue;
315 count += *(long *)(dpcpu + (uintptr_t)arg1);
316 }
317 return (SYSCTL_OUT(req, &count, sizeof(count)));
318 }
319
320 int
321 sysctl_dpcpu_int(SYSCTL_HANDLER_ARGS)
322 {
323 uintptr_t dpcpu;
324 int count;
325 int i;
326
327 count = 0;
328 CPU_FOREACH(i) {
329 dpcpu = dpcpu_off[i];
330 if (dpcpu == 0)
331 continue;
332 count += *(int *)(dpcpu + (uintptr_t)arg1);
333 }
334 return (SYSCTL_OUT(req, &count, sizeof(count)));
335 }
336
337 #ifdef DDB
338 DB_SHOW_COMMAND(dpcpu_off, db_show_dpcpu_off)
339 {
340 int id;
341
342 CPU_FOREACH(id) {
343 db_printf("dpcpu_off[%2d] = 0x%jx (+ DPCPU_START = %p)\n",
344 id, (uintmax_t)dpcpu_off[id],
345 (void *)(uintptr_t)(dpcpu_off[id] + DPCPU_START));
346 }
347 }
348
349 static void
350 show_pcpu(struct pcpu *pc)
351 {
352 struct thread *td;
353
354 db_printf("cpuid = %d\n", pc->pc_cpuid);
355 db_printf("dynamic pcpu = %p\n", (void *)pc->pc_dynamic);
356 db_printf("curthread = ");
357 td = pc->pc_curthread;
358 if (td != NULL)
359 db_printf("%p: pid %d tid %d \"%s\"\n", td, td->td_proc->p_pid,
360 td->td_tid, td->td_name);
361 else
362 db_printf("none\n");
363 db_printf("curpcb = %p\n", pc->pc_curpcb);
364 db_printf("fpcurthread = ");
365 td = pc->pc_fpcurthread;
366 if (td != NULL)
367 db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
368 td->td_name);
369 else
370 db_printf("none\n");
371 db_printf("idlethread = ");
372 td = pc->pc_idlethread;
373 if (td != NULL)
374 db_printf("%p: tid %d \"%s\"\n", td, td->td_tid, td->td_name);
375 else
376 db_printf("none\n");
377 db_show_mdpcpu(pc);
378
379 #ifdef VIMAGE
380 db_printf("curvnet = %p\n", pc->pc_curthread->td_vnet);
381 #endif
382
383 #ifdef WITNESS
384 db_printf("spin locks held:\n");
385 witness_list_locks(&pc->pc_spinlocks, db_printf);
386 #endif
387 }
388
389 DB_SHOW_COMMAND(pcpu, db_show_pcpu)
390 {
391 struct pcpu *pc;
392 int id;
393
394 if (have_addr)
395 id = ((addr >> 4) % 16) * 10 + (addr % 16);
396 else
397 id = PCPU_GET(cpuid);
398 pc = pcpu_find(id);
399 if (pc == NULL) {
400 db_printf("CPU %d not found\n", id);
401 return;
402 }
403 show_pcpu(pc);
404 }
405
406 DB_SHOW_ALL_COMMAND(pcpu, db_show_cpu_all)
407 {
408 struct pcpu *pc;
409 int id;
410
411 db_printf("Current CPU: %d\n\n", PCPU_GET(cpuid));
412 CPU_FOREACH(id) {
413 pc = pcpu_find(id);
414 if (pc != NULL) {
415 show_pcpu(pc);
416 db_printf("\n");
417 }
418 }
419 }
420 DB_SHOW_ALIAS(allpcpu, db_show_cpu_all);
421 #endif
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