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/8.3/sys/kern/subr_pcpu.c 221125 2011-04-27 18:00:46Z jhb $");
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 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 = SLIST_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 pcpu->pc_cpumask = 1 << cpuid;
91 cpuid_to_pcpu[cpuid] = pcpu;
92 SLIST_INSERT_HEAD(&cpuhead, pcpu, pc_allcpu);
93 cpu_pcpu_init(pcpu, cpuid, size);
94 pcpu->pc_rm_queue.rmq_next = &pcpu->pc_rm_queue;
95 pcpu->pc_rm_queue.rmq_prev = &pcpu->pc_rm_queue;
96 #ifdef KTR
97 snprintf(pcpu->pc_name, sizeof(pcpu->pc_name), "CPU %d", cpuid);
98 #endif
99 }
100
101 void
102 dpcpu_init(void *dpcpu, int cpuid)
103 {
104 struct pcpu *pcpu;
105
106 pcpu = pcpu_find(cpuid);
107 pcpu->pc_dynamic = (uintptr_t)dpcpu - DPCPU_START;
108
109 /*
110 * Initialize defaults from our linker section.
111 */
112 memcpy(dpcpu, (void *)DPCPU_START, DPCPU_BYTES);
113
114 /*
115 * Place it in the global pcpu offset array.
116 */
117 dpcpu_off[cpuid] = pcpu->pc_dynamic;
118 }
119
120 static void
121 dpcpu_startup(void *dummy __unused)
122 {
123 struct dpcpu_free *df;
124
125 df = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
126 df->df_start = (uintptr_t)&DPCPU_NAME(modspace);
127 df->df_len = DPCPU_MODMIN;
128 TAILQ_INSERT_HEAD(&dpcpu_head, df, df_link);
129 sx_init(&dpcpu_lock, "dpcpu alloc lock");
130 }
131 SYSINIT(dpcpu, SI_SUB_KLD, SI_ORDER_FIRST, dpcpu_startup, 0);
132
133 /*
134 * First-fit extent based allocator for allocating space in the per-cpu
135 * region reserved for modules. This is only intended for use by the
136 * kernel linkers to place module linker sets.
137 */
138 void *
139 dpcpu_alloc(int size)
140 {
141 struct dpcpu_free *df;
142 void *s;
143
144 s = NULL;
145 size = roundup2(size, sizeof(void *));
146 sx_xlock(&dpcpu_lock);
147 TAILQ_FOREACH(df, &dpcpu_head, df_link) {
148 if (df->df_len < size)
149 continue;
150 if (df->df_len == size) {
151 s = (void *)df->df_start;
152 TAILQ_REMOVE(&dpcpu_head, df, df_link);
153 free(df, M_PCPU);
154 break;
155 }
156 s = (void *)df->df_start;
157 df->df_len -= size;
158 df->df_start = df->df_start + size;
159 break;
160 }
161 sx_xunlock(&dpcpu_lock);
162
163 return (s);
164 }
165
166 /*
167 * Free dynamic per-cpu space at module unload time.
168 */
169 void
170 dpcpu_free(void *s, int size)
171 {
172 struct dpcpu_free *df;
173 struct dpcpu_free *dn;
174 uintptr_t start;
175 uintptr_t end;
176
177 size = roundup2(size, sizeof(void *));
178 start = (uintptr_t)s;
179 end = start + size;
180 /*
181 * Free a region of space and merge it with as many neighbors as
182 * possible. Keeping the list sorted simplifies this operation.
183 */
184 sx_xlock(&dpcpu_lock);
185 TAILQ_FOREACH(df, &dpcpu_head, df_link) {
186 if (df->df_start > end)
187 break;
188 /*
189 * If we expand at the end of an entry we may have to
190 * merge it with the one following it as well.
191 */
192 if (df->df_start + df->df_len == start) {
193 df->df_len += size;
194 dn = TAILQ_NEXT(df, df_link);
195 if (df->df_start + df->df_len == dn->df_start) {
196 df->df_len += dn->df_len;
197 TAILQ_REMOVE(&dpcpu_head, dn, df_link);
198 free(dn, M_PCPU);
199 }
200 sx_xunlock(&dpcpu_lock);
201 return;
202 }
203 if (df->df_start == end) {
204 df->df_start = start;
205 df->df_len += size;
206 sx_xunlock(&dpcpu_lock);
207 return;
208 }
209 }
210 dn = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
211 dn->df_start = start;
212 dn->df_len = size;
213 if (df)
214 TAILQ_INSERT_BEFORE(df, dn, df_link);
215 else
216 TAILQ_INSERT_TAIL(&dpcpu_head, dn, df_link);
217 sx_xunlock(&dpcpu_lock);
218 }
219
220 /*
221 * Initialize the per-cpu storage from an updated linker-set region.
222 */
223 void
224 dpcpu_copy(void *s, int size)
225 {
226 #ifdef SMP
227 uintptr_t dpcpu;
228 int i;
229
230 for (i = 0; i < mp_ncpus; ++i) {
231 dpcpu = dpcpu_off[i];
232 if (dpcpu == 0)
233 continue;
234 memcpy((void *)(dpcpu + (uintptr_t)s), s, size);
235 }
236 #else
237 memcpy((void *)(dpcpu_off[0] + (uintptr_t)s), s, size);
238 #endif
239 }
240
241 /*
242 * Destroy a struct pcpu.
243 */
244 void
245 pcpu_destroy(struct pcpu *pcpu)
246 {
247
248 SLIST_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
249 cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
250 dpcpu_off[pcpu->pc_cpuid] = 0;
251 }
252
253 /*
254 * Locate a struct pcpu by cpu id.
255 */
256 struct pcpu *
257 pcpu_find(u_int cpuid)
258 {
259
260 return (cpuid_to_pcpu[cpuid]);
261 }
262
263 int
264 sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS)
265 {
266 uintptr_t dpcpu;
267 int64_t count;
268 int i;
269
270 count = 0;
271 for (i = 0; i < mp_ncpus; ++i) {
272 dpcpu = dpcpu_off[i];
273 if (dpcpu == 0)
274 continue;
275 count += *(int64_t *)(dpcpu + (uintptr_t)arg1);
276 }
277 return (SYSCTL_OUT(req, &count, sizeof(count)));
278 }
279
280 int
281 sysctl_dpcpu_long(SYSCTL_HANDLER_ARGS)
282 {
283 uintptr_t dpcpu;
284 long count;
285 int i;
286
287 count = 0;
288 for (i = 0; i < mp_ncpus; ++i) {
289 dpcpu = dpcpu_off[i];
290 if (dpcpu == 0)
291 continue;
292 count += *(long *)(dpcpu + (uintptr_t)arg1);
293 }
294 return (SYSCTL_OUT(req, &count, sizeof(count)));
295 }
296
297 int
298 sysctl_dpcpu_int(SYSCTL_HANDLER_ARGS)
299 {
300 uintptr_t dpcpu;
301 int count;
302 int i;
303
304 count = 0;
305 for (i = 0; i < mp_ncpus; ++i) {
306 dpcpu = dpcpu_off[i];
307 if (dpcpu == 0)
308 continue;
309 count += *(int *)(dpcpu + (uintptr_t)arg1);
310 }
311 return (SYSCTL_OUT(req, &count, sizeof(count)));
312 }
313
314 #ifdef DDB
315 DB_SHOW_COMMAND(dpcpu_off, db_show_dpcpu_off)
316 {
317 int id;
318
319 CPU_FOREACH(id) {
320 db_printf("dpcpu_off[%2d] = 0x%jx (+ DPCPU_START = %p)\n",
321 id, (uintmax_t)dpcpu_off[id],
322 (void *)(uintptr_t)(dpcpu_off[id] + DPCPU_START));
323 }
324 }
325
326 static void
327 show_pcpu(struct pcpu *pc)
328 {
329 struct thread *td;
330
331 db_printf("cpuid = %d\n", pc->pc_cpuid);
332 db_printf("dynamic pcpu = %p\n", (void *)pc->pc_dynamic);
333 db_printf("curthread = ");
334 td = pc->pc_curthread;
335 if (td != NULL)
336 db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
337 td->td_name);
338 else
339 db_printf("none\n");
340 db_printf("curpcb = %p\n", pc->pc_curpcb);
341 db_printf("fpcurthread = ");
342 td = pc->pc_fpcurthread;
343 if (td != NULL)
344 db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
345 td->td_name);
346 else
347 db_printf("none\n");
348 db_printf("idlethread = ");
349 td = pc->pc_idlethread;
350 if (td != NULL)
351 db_printf("%p: tid %d \"%s\"\n", td, td->td_tid, td->td_name);
352 else
353 db_printf("none\n");
354 db_show_mdpcpu(pc);
355
356 #ifdef VIMAGE
357 db_printf("curvnet = %p\n", pc->pc_curthread->td_vnet);
358 #endif
359
360 #ifdef WITNESS
361 db_printf("spin locks held:\n");
362 witness_list_locks(&pc->pc_spinlocks, db_printf);
363 #endif
364 }
365
366 DB_SHOW_COMMAND(pcpu, db_show_pcpu)
367 {
368 struct pcpu *pc;
369 int id;
370
371 if (have_addr)
372 id = ((addr >> 4) % 16) * 10 + (addr % 16);
373 else
374 id = PCPU_GET(cpuid);
375 pc = pcpu_find(id);
376 if (pc == NULL) {
377 db_printf("CPU %d not found\n", id);
378 return;
379 }
380 show_pcpu(pc);
381 }
382
383 DB_SHOW_ALL_COMMAND(pcpu, db_show_cpu_all)
384 {
385 struct pcpu *pc;
386 int id;
387
388 db_printf("Current CPU: %d\n\n", PCPU_GET(cpuid));
389 for (id = 0; id <= mp_maxid; id++) {
390 pc = pcpu_find(id);
391 if (pc != NULL) {
392 show_pcpu(pc);
393 db_printf("\n");
394 }
395 }
396 }
397 DB_SHOW_ALIAS(allpcpu, db_show_cpu_all);
398 #endif
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