xref: /freebsd/sys/kern/kern_pmc.c (revision f0a75d274af375d15b97b830966b99a02b7db911)
1 /*-
2  * Copyright (c) 2003-2005, Joseph Koshy
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #include "opt_hwpmc_hooks.h"
30 
31 #include <sys/types.h>
32 #include <sys/pmc.h>
33 #include <sys/pmckern.h>
34 #include <sys/smp.h>
35 
36 #ifdef	HWPMC_HOOKS
37 #define	PMC_KERNEL_VERSION	PMC_VERSION
38 #else
39 #define	PMC_KERNEL_VERSION	0
40 #endif
41 
42 const int pmc_kernel_version = PMC_KERNEL_VERSION;
43 
44 /* Hook variable. */
45 int (*pmc_hook)(struct thread *td, int function, void *arg) = NULL;
46 
47 /* Interrupt handler */
48 int (*pmc_intr)(int cpu, uintptr_t pc, int usermode) = NULL;
49 
50 /* Bitmask of CPUs requiring servicing at hardclock time */
51 volatile cpumask_t pmc_cpumask;
52 
53 /*
54  * A global count of SS mode PMCs.  When non-zero, this means that
55  * we have processes that are sampling the system as a whole.
56  */
57 volatile int pmc_ss_count;
58 
59 /*
60  * Since PMC(4) may not be loaded in the current kernel, the
61  * convention followed is that a non-NULL value of 'pmc_hook' implies
62  * the presence of this kernel module.
63  *
64  * This requires us to protect 'pmc_hook' with a
65  * shared (sx) lock -- thus making the process of calling into PMC(4)
66  * somewhat more expensive than a simple 'if' check and indirect call.
67  */
68 struct sx pmc_sx;
69 SX_SYSINIT(pmc, &pmc_sx, "pmc shared lock");
70 
71 /*
72  * Helper functions
73  */
74 
75 int
76 pmc_cpu_is_disabled(int cpu)
77 {
78 #ifdef	SMP
79 	return ((hlt_cpus_mask & (1 << cpu)) != 0);
80 #else
81 	return 0;
82 #endif
83 }
84 
85 int
86 pmc_cpu_is_logical(int cpu)
87 {
88 #ifdef	SMP
89 	return ((logical_cpus_mask & (1 << cpu)) != 0);
90 #else
91 	return 0;
92 #endif
93 }
94