xref: /freebsd/sys/kern/kern_pmc.c (revision 271c3a9060f2ee55607ebe146523f888e1db2654)
1 /*-
2  * Copyright (c) 2003-2007 Joseph Koshy
3  * Copyright (c) 2007 The FreeBSD Foundation
4  * All rights reserved.
5  *
6  * Portions of this software were developed by A. Joseph Koshy under
7  * sponsorship from the FreeBSD Foundation and Google, Inc.
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  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include "opt_hwpmc_hooks.h"
35 
36 #include <sys/types.h>
37 #include <sys/pmc.h>
38 #include <sys/pmckern.h>
39 #include <sys/smp.h>
40 
41 #ifdef	HWPMC_HOOKS
42 #define	PMC_KERNEL_VERSION	PMC_VERSION
43 #else
44 #define	PMC_KERNEL_VERSION	0
45 #endif
46 
47 const int pmc_kernel_version = PMC_KERNEL_VERSION;
48 
49 /* Hook variable. */
50 int (*pmc_hook)(struct thread *td, int function, void *arg) = NULL;
51 
52 /* Interrupt handler */
53 int (*pmc_intr)(int cpu, struct trapframe *tf) = NULL;
54 
55 /* Bitmask of CPUs requiring servicing at hardclock time */
56 volatile cpumask_t pmc_cpumask;
57 
58 /*
59  * A global count of SS mode PMCs.  When non-zero, this means that
60  * we have processes that are sampling the system as a whole.
61  */
62 volatile int pmc_ss_count;
63 
64 /*
65  * Since PMC(4) may not be loaded in the current kernel, the
66  * convention followed is that a non-NULL value of 'pmc_hook' implies
67  * the presence of this kernel module.
68  *
69  * This requires us to protect 'pmc_hook' with a
70  * shared (sx) lock -- thus making the process of calling into PMC(4)
71  * somewhat more expensive than a simple 'if' check and indirect call.
72  */
73 struct sx pmc_sx;
74 
75 static void
76 pmc_init_sx(void)
77 {
78 	sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS);
79 }
80 
81 SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL);
82 
83 /*
84  * Helper functions
85  */
86 
87 int
88 pmc_cpu_is_disabled(int cpu)
89 {
90 #ifdef	SMP
91 	return ((hlt_cpus_mask & (1 << cpu)) != 0);
92 #else
93 	return 0;
94 #endif
95 }
96 
97 int
98 pmc_cpu_is_logical(int cpu)
99 {
100 #ifdef	SMP
101 	return ((logical_cpus_mask & (1 << cpu)) != 0);
102 #else
103 	return 0;
104 #endif
105 }
106