xref: /freebsd/sys/kern/subr_pcpu.c (revision 6fd05b64b5b65dd4ba9b86482a0634a5f0b96c29)
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("$FreeBSD$");
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 
58 static struct pcpu *cpuid_to_pcpu[MAXCPU];
59 struct cpuhead cpuhead = SLIST_HEAD_INITIALIZER(cpuhead);
60 
61 /*
62  * Initialize the MI portions of a struct pcpu.
63  */
64 void
65 pcpu_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  */
81 void
82 pcpu_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  */
92 struct pcpu *
93 pcpu_find(u_int cpuid)
94 {
95 
96 	return (cpuid_to_pcpu[cpuid]);
97 }
98 
99 #ifdef DDB
100 DB_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