subr_pcpu.c revision 139804 
1/*-
2 * Copyright (c) 2001 Wind River Systems, Inc.
3 * All rights reserved.
4 * Written by: John Baldwin <jhb@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 4. Neither the name of the author nor the names of any co-contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31/*
32 * This module provides MI support for per-cpu data.
33 *
34 * Each architecture determines the mapping of logical CPU IDs to physical
35 * CPUs.  The requirements of this mapping are as follows:
36 *  - Logical CPU IDs must reside in the range 0 ... MAXCPU - 1.
37 *  - The mapping is not required to be dense.  That is, there may be
38 *    gaps in the mappings.
39 *  - The platform sets the value of MAXCPU in <machine/param.h>.
40 *  - It is suggested, but not required, that in the non-SMP case, the
41 *    platform define MAXCPU to be 1 and define the logical ID of the
42 *    sole CPU as 0.
43 */
44
45#include <sys/cdefs.h>
46__FBSDID("$FreeBSD: head/sys/kern/subr_pcpu.c 139804 2005-01-06 23:35:40Z imp $");
47
48#include "opt_ddb.h"
49
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/linker_set.h>
53#include <sys/lock.h>
54#include <sys/pcpu.h>
55#include <sys/proc.h>
56#include <ddb/ddb.h>
57
58static struct pcpu *cpuid_to_pcpu[MAXCPU];
59struct cpuhead cpuhead = SLIST_HEAD_INITIALIZER(cpuhead);
60
61/*
62 * Initialize the MI portions of a struct pcpu.
63 */
64void
65pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
66{
67
68	bzero(pcpu, size);
69	KASSERT(cpuid >= 0 && cpuid < MAXCPU,
70	    ("pcpu_init: invalid cpuid %d", cpuid));
71	pcpu->pc_cpuid = cpuid;
72	pcpu->pc_cpumask = 1 << cpuid;
73	cpuid_to_pcpu[cpuid] = pcpu;
74	SLIST_INSERT_HEAD(&cpuhead, pcpu, pc_allcpu);
75	cpu_pcpu_init(pcpu, cpuid, size);
76}
77
78/*
79 * Destroy a struct pcpu.
80 */
81void
82pcpu_destroy(struct pcpu *pcpu)
83{
84
85	SLIST_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
86	cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
87}
88
89/*
90 * Locate a struct pcpu by cpu id.
91 */
92struct pcpu *
93pcpu_find(u_int cpuid)
94{
95
96	return (cpuid_to_pcpu[cpuid]);
97}
98
99#ifdef DDB
100DB_SHOW_COMMAND(pcpu, db_show_pcpu)
101{
102	struct pcpu *pc;
103	struct thread *td;
104	int id;
105
106	if (have_addr)
107		id = ((addr >> 4) % 16) * 10 + (addr % 16);
108	else
109		id = PCPU_GET(cpuid);
110	pc = pcpu_find(id);
111	if (pc == NULL) {
112		db_printf("CPU %d not found\n", id);
113		return;
114	}
115	db_printf("cpuid        = %d\n", pc->pc_cpuid);
116	db_printf("curthread    = ");
117	td = pc->pc_curthread;
118	if (td != NULL)
119		db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
120		    td->td_proc->p_comm);
121	else
122		db_printf("none\n");
123	db_printf("curpcb       = %p\n", pc->pc_curpcb);
124	db_printf("fpcurthread  = ");
125	td = pc->pc_fpcurthread;
126	if (td != NULL)
127		db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
128		    td->td_proc->p_comm);
129	else
130		db_printf("none\n");
131	db_printf("idlethread   = ");
132	td = pc->pc_idlethread;
133	if (td != NULL)
134		db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
135		    td->td_proc->p_comm);
136	else
137		db_printf("none\n");
138	db_show_mdpcpu(pc);
139
140#ifdef WITNESS
141	db_printf("spin locks held:\n");
142	witness_list_locks(&pc->pc_spinlocks);
143#endif
144}
145#endif
146