subr_pcpu.c revision 194784
1169689Skan/*-
2169689Skan * Copyright (c) 2001 Wind River Systems, Inc.
3169689Skan * All rights reserved.
4169689Skan * Written by: John Baldwin <jhb@FreeBSD.org>
5169689Skan *
6169689Skan * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
7169689Skan * All rights reserved.
8169689Skan *
9169689Skan * Redistribution and use in source and binary forms, with or without
10169689Skan * modification, are permitted provided that the following conditions
11169689Skan * are met:
12169689Skan * 1. Redistributions of source code must retain the above copyright
13169689Skan *    notice, this list of conditions and the following disclaimer.
14169689Skan * 2. Redistributions in binary form must reproduce the above copyright
15169689Skan *    notice, this list of conditions and the following disclaimer in the
16169689Skan *    documentation and/or other materials provided with the distribution.
17169689Skan * 4. Neither the name of the author nor the names of any co-contributors
18169689Skan *    may be used to endorse or promote products derived from this software
19169689Skan *    without specific prior written permission.
20169689Skan *
21169689Skan * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22169689Skan * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23169689Skan * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24169689Skan * 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: head/sys/kern/subr_pcpu.c 194784 2009-06-23 22:42:39Z jeff $");
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/linker_set.h>
57#include <sys/lock.h>
58#include <sys/malloc.h>
59#include <sys/pcpu.h>
60#include <sys/proc.h>
61#include <sys/smp.h>
62#include <sys/sx.h>
63#include <ddb/ddb.h>
64
65MALLOC_DEFINE(M_PCPU, "Per-cpu", "Per-cpu resource accouting.");
66
67struct dpcpu_free {
68	uintptr_t	df_start;
69	int		df_len;
70	TAILQ_ENTRY(dpcpu_free) df_link;
71};
72
73static DPCPU_DEFINE(char, modspace[DPCPU_MODMIN]);
74static TAILQ_HEAD(, dpcpu_free) dpcpu_head = TAILQ_HEAD_INITIALIZER(dpcpu_head);
75static struct sx dpcpu_lock;
76uintptr_t dpcpu_off[MAXCPU];
77struct pcpu *cpuid_to_pcpu[MAXCPU];
78struct cpuhead cpuhead = SLIST_HEAD_INITIALIZER(cpuhead);
79
80/*
81 * Initialize the MI portions of a struct pcpu.
82 */
83void
84pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
85{
86
87	bzero(pcpu, size);
88	KASSERT(cpuid >= 0 && cpuid < MAXCPU,
89	    ("pcpu_init: invalid cpuid %d", cpuid));
90	pcpu->pc_cpuid = cpuid;
91	pcpu->pc_cpumask = 1 << cpuid;
92	cpuid_to_pcpu[cpuid] = pcpu;
93	SLIST_INSERT_HEAD(&cpuhead, pcpu, pc_allcpu);
94	cpu_pcpu_init(pcpu, cpuid, size);
95	pcpu->pc_rm_queue.rmq_next = &pcpu->pc_rm_queue;
96	pcpu->pc_rm_queue.rmq_prev = &pcpu->pc_rm_queue;
97#ifdef KTR
98	snprintf(pcpu->pc_name, sizeof(pcpu->pc_name), "CPU %d", cpuid);
99#endif
100}
101
102void
103dpcpu_init(void *dpcpu, int cpuid)
104{
105	struct pcpu *pcpu;
106
107	pcpu = pcpu_find(cpuid);
108	pcpu->pc_dynamic = (uintptr_t)dpcpu - DPCPU_START;
109
110	/*
111	 * Initialize defaults from our linker section.
112	 */
113	memcpy(dpcpu, (void *)DPCPU_START, DPCPU_BYTES);
114
115	/*
116	 * Place it in the global pcpu offset array.
117	 */
118	dpcpu_off[cpuid] = pcpu->pc_dynamic;
119}
120
121static void
122dpcpu_startup(void *dummy __unused)
123{
124	struct dpcpu_free *df;
125
126	df = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
127	df->df_start = (uintptr_t)&DPCPU_NAME(modspace);
128	df->df_len = DPCPU_MODSIZE;
129	TAILQ_INSERT_HEAD(&dpcpu_head, df, df_link);
130	sx_init(&dpcpu_lock, "dpcpu alloc lock");
131}
132SYSINIT(dpcpu, SI_SUB_KLD, SI_ORDER_FIRST, dpcpu_startup, 0);
133
134/*
135 * First-fit extent based allocator for allocating space in the per-cpu
136 * region reserved for modules.  This is only intended for use by the
137 * kernel linkers to place module linker sets.
138 */
139void *
140dpcpu_alloc(int size)
141{
142	struct dpcpu_free *df;
143	void *s;
144
145	s = NULL;
146	size = roundup2(size, sizeof(void *));
147	sx_xlock(&dpcpu_lock);
148	TAILQ_FOREACH(df, &dpcpu_head, df_link) {
149		if (df->df_len < size)
150			continue;
151		if (df->df_len == size) {
152			s = (void *)df->df_start;
153			TAILQ_REMOVE(&dpcpu_head, df, df_link);
154			free(df, M_PCPU);
155			break;
156		}
157		s = (void *)df->df_start;
158		df->df_len -= size;
159		df->df_start = df->df_start + size;
160		break;
161	}
162	sx_xunlock(&dpcpu_lock);
163
164	return (s);
165}
166
167/*
168 * Free dynamic per-cpu space at module unload time.
169 */
170void
171dpcpu_free(void *s, int size)
172{
173	struct dpcpu_free *df;
174	struct dpcpu_free *dn;
175	uintptr_t start;
176	uintptr_t end;
177
178	size = roundup2(size, sizeof(void *));
179	start = (uintptr_t)s;
180	end = start + size;
181	/*
182	 * Free a region of space and merge it with as many neighbors as
183	 * possible.  Keeping the list sorted simplifies this operation.
184	 */
185	sx_xlock(&dpcpu_lock);
186	TAILQ_FOREACH(df, &dpcpu_head, df_link) {
187		if (df->df_start > end)
188			break;
189		/*
190		 * If we expand at the end of an entry we may have to
191		 * merge it with the one following it as well.
192		 */
193		if (df->df_start + df->df_len == start) {
194			df->df_len += size;
195			dn = TAILQ_NEXT(df, df_link);
196			if (df->df_start + df->df_len == dn->df_start) {
197				df->df_len += dn->df_len;
198				TAILQ_REMOVE(&dpcpu_head, dn, df_link);
199				free(dn, M_PCPU);
200			}
201			sx_xunlock(&dpcpu_lock);
202			return;
203		}
204		if (df->df_start == end) {
205			df->df_start = start;
206			df->df_len += size;
207			sx_xunlock(&dpcpu_lock);
208			return;
209		}
210	}
211	dn = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
212	dn->df_start = start;
213	dn->df_len = size;
214	if (df)
215		TAILQ_INSERT_BEFORE(df, dn, df_link);
216	else
217		TAILQ_INSERT_TAIL(&dpcpu_head, dn, df_link);
218	sx_xunlock(&dpcpu_lock);
219}
220
221/*
222 * Initialize the per-cpu storage from an updated linker-set region.
223 */
224void
225dpcpu_copy(void *s, int size)
226{
227#ifdef SMP
228	uintptr_t dpcpu;
229	int i;
230
231	for (i = 0; i < mp_ncpus; ++i) {
232		dpcpu = dpcpu_off[i];
233		if (dpcpu == 0)
234			continue;
235		memcpy((void *)(dpcpu + (uintptr_t)s), s, size);
236	}
237#else
238	memcpy((void *)(dpcpu_off[0] + (uintptr_t)s), s, size);
239#endif
240}
241
242/*
243 * Destroy a struct pcpu.
244 */
245void
246pcpu_destroy(struct pcpu *pcpu)
247{
248
249	SLIST_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
250	cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
251	dpcpu_off[pcpu->pc_cpuid] = 0;
252}
253
254/*
255 * Locate a struct pcpu by cpu id.
256 */
257struct pcpu *
258pcpu_find(u_int cpuid)
259{
260
261	return (cpuid_to_pcpu[cpuid]);
262}
263
264int
265sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS)
266{
267	int64_t count;
268#ifdef SMP
269	uintptr_t dpcpu;
270	int i;
271
272	count = 0;
273	for (i = 0; i < mp_ncpus; ++i) {
274		dpcpu = dpcpu_off[i];
275		if (dpcpu == 0)
276			continue;
277		count += *(int64_t *)(dpcpu + (uintptr_t)arg1);
278	}
279#else
280	count = *(int64_t *)(dpcpu_off[0] + (uintptr_t)arg1);
281#endif
282	return (SYSCTL_OUT(req, &count, sizeof(count)));
283}
284
285int
286sysctl_dpcpu_int(SYSCTL_HANDLER_ARGS)
287{
288	int count;
289#ifdef SMP
290	uintptr_t dpcpu;
291	int i;
292
293	count = 0;
294	for (i = 0; i < mp_ncpus; ++i) {
295		dpcpu = dpcpu_off[i];
296		if (dpcpu == 0)
297			continue;
298		count += *(int *)(dpcpu + (uintptr_t)arg1);
299	}
300#else
301	count = *(int *)(dpcpu_off[0] + (uintptr_t)arg1);
302#endif
303	return (SYSCTL_OUT(req, &count, sizeof(count)));
304}
305
306#ifdef DDB
307
308static void
309show_pcpu(struct pcpu *pc)
310{
311	struct thread *td;
312
313	db_printf("cpuid        = %d\n", pc->pc_cpuid);
314	db_printf("dynamic pcpu	= %p\n", (void *)pc->pc_dynamic);
315	db_printf("curthread    = ");
316	td = pc->pc_curthread;
317	if (td != NULL)
318		db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
319		    td->td_name);
320	else
321		db_printf("none\n");
322	db_printf("curpcb       = %p\n", pc->pc_curpcb);
323	db_printf("fpcurthread  = ");
324	td = pc->pc_fpcurthread;
325	if (td != NULL)
326		db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
327		    td->td_name);
328	else
329		db_printf("none\n");
330	db_printf("idlethread   = ");
331	td = pc->pc_idlethread;
332	if (td != NULL)
333		db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
334		    td->td_name);
335	else
336		db_printf("none\n");
337	db_show_mdpcpu(pc);
338
339#ifdef VIMAGE
340	db_printf("curvnet      = %p\n", pc->pc_curthread->td_vnet);
341#endif
342
343#ifdef WITNESS
344	db_printf("spin locks held:\n");
345	witness_list_locks(&pc->pc_spinlocks);
346#endif
347}
348
349DB_SHOW_COMMAND(pcpu, db_show_pcpu)
350{
351	struct pcpu *pc;
352	int id;
353
354	if (have_addr)
355		id = ((addr >> 4) % 16) * 10 + (addr % 16);
356	else
357		id = PCPU_GET(cpuid);
358	pc = pcpu_find(id);
359	if (pc == NULL) {
360		db_printf("CPU %d not found\n", id);
361		return;
362	}
363	show_pcpu(pc);
364}
365
366DB_SHOW_ALL_COMMAND(pcpu, db_show_cpu_all)
367{
368	struct pcpu *pc;
369	int id;
370
371	db_printf("Current CPU: %d\n\n", PCPU_GET(cpuid));
372	for (id = 0; id <= mp_maxid; id++) {
373		pc = pcpu_find(id);
374		if (pc != NULL) {
375			show_pcpu(pc);
376			db_printf("\n");
377		}
378	}
379}
380DB_SHOW_ALIAS(allpcpu, db_show_cpu_all);
381#endif
382