2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2003-2008 Joseph Koshy
5 * Copyright (c) 2007 The FreeBSD Foundation
8 * Portions of this software were developed by A. Joseph Koshy under
9 * sponsorship from the FreeBSD Foundation and Google, Inc.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
36 #include "opt_hwpmc_hooks.h"
38 #include <sys/types.h>
39 #include <sys/ctype.h>
40 #include <sys/param.h>
41 #include <sys/malloc.h>
42 #include <sys/kernel.h>
44 #include <sys/mutex.h>
46 #include <sys/pmckern.h>
48 #include <sys/sysctl.h>
49 #include <sys/systm.h>
52 FEATURE(hwpmc_hooks, "Kernel support for HW PMC");
53 #define PMC_KERNEL_VERSION PMC_VERSION
55 #define PMC_KERNEL_VERSION 0
58 MALLOC_DECLARE(M_PMCHOOKS);
59 MALLOC_DEFINE(M_PMCHOOKS, "pmchooks", "Memory space for PMC hooks");
61 const int pmc_kernel_version = PMC_KERNEL_VERSION;
64 int __read_mostly (*pmc_hook)(struct thread *td, int function, void *arg) = NULL;
66 /* Interrupt handler */
67 int __read_mostly (*pmc_intr)(int cpu, struct trapframe *tf) = NULL;
69 /* Bitmask of CPUs requiring servicing at hardclock time */
70 volatile cpuset_t pmc_cpumask;
73 * A global count of SS mode PMCs. When non-zero, this means that
74 * we have processes that are sampling the system as a whole.
76 volatile int pmc_ss_count;
79 * Since PMC(4) may not be loaded in the current kernel, the
80 * convention followed is that a non-NULL value of 'pmc_hook' implies
81 * the presence of this kernel module.
83 * This requires us to protect 'pmc_hook' with a
84 * shared (sx) lock -- thus making the process of calling into PMC(4)
85 * somewhat more expensive than a simple 'if' check and indirect call.
90 * PMC Soft per cpu trapframe.
92 struct trapframe pmc_tf[MAXCPU];
95 * PMC Soft use a global table to store registered events.
98 SYSCTL_NODE(_kern, OID_AUTO, hwpmc, CTLFLAG_RW, 0, "HWPMC parameters");
100 static int pmc_softevents = 16;
101 SYSCTL_INT(_kern_hwpmc, OID_AUTO, softevents, CTLFLAG_RDTUN,
102 &pmc_softevents, 0, "maximum number of soft events");
104 struct mtx pmc_softs_mtx;
106 struct pmc_soft **pmc_softs;
108 MTX_SYSINIT(pmc_soft_mtx, &pmc_softs_mtx, "pmc-softs", MTX_SPIN);
113 sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS);
116 SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL);
123 * A note on the CPU numbering scheme used by the hwpmc(4) driver.
125 * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1].
126 * CPUs could be numbered "sparsely" in this range; the predicate
127 * `pmc_cpu_is_present()' is used to test whether a given CPU is
128 * physically present.
130 * Further, a CPU that is physically present may be administratively
131 * disabled or otherwise unavailable for use by hwpmc(4). The
132 * `pmc_cpu_is_active()' predicate tests for CPU usability. An
133 * "active" CPU participates in thread scheduling and can field
134 * interrupts raised by PMC hardware.
136 * On systems with hyperthreaded CPUs, multiple logical CPUs may share
137 * PMC hardware resources. For such processors one logical CPU is
138 * denoted as the primary owner of the in-CPU PMC resources. The
139 * pmc_cpu_is_primary() predicate is used to distinguish this primary
140 * CPU from the others.
144 pmc_cpu_is_active(int cpu)
147 return (pmc_cpu_is_present(cpu) &&
148 !CPU_ISSET(cpu, &hlt_cpus_mask));
156 pmc_cpu_is_disabled(int cpu)
158 return (!pmc_cpu_is_active(cpu));
162 pmc_cpu_is_present(int cpu)
165 return (!CPU_ABSENT(cpu));
172 pmc_cpu_is_primary(int cpu)
175 return (!CPU_ISSET(cpu, &logical_cpus_mask));
183 * Return the maximum CPU number supported by the system. The return
184 * value is used for scaling internal data structures and for runtime
200 * Return the count of CPUs in the `active' state in the system.
203 pmc_cpu_max_active(void)
207 * When support for CPU hot-plugging is added to the kernel,
208 * this function would change to return the current number
220 * Cleanup event name:
221 * - remove duplicate '_'
225 pmc_soft_namecleanup(char *name)
231 for ( ; *p == '_' ; p++)
234 if (*p == '_' && (*(p + 1) == '_' || *(p + 1) == '\0'))
243 pmc_soft_ev_register(struct pmc_soft *ps)
245 static int warned = 0;
249 ps->ps_ev.pm_ev_code = 0; /* invalid */
250 pmc_soft_namecleanup(ps->ps_ev.pm_ev_name);
252 mtx_lock_spin(&pmc_softs_mtx);
254 if (pmc_softs_count >= pmc_softevents) {
256 * XXX Reusing events can enter a race condition where
257 * new allocated event will be used as an old one.
259 for (n = 0; n < pmc_softevents; n++)
260 if (pmc_softs[n] == NULL)
262 if (n == pmc_softevents) {
263 mtx_unlock_spin(&pmc_softs_mtx);
265 printf("hwpmc: too many soft events, "
266 "increase kern.hwpmc.softevents tunable\n");
272 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + n;
275 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + pmc_softs_count;
276 pmc_softs[pmc_softs_count++] = ps;
279 mtx_unlock_spin(&pmc_softs_mtx);
283 pmc_soft_ev_deregister(struct pmc_soft *ps)
286 KASSERT(ps != NULL, ("pmc_soft_deregister: called with NULL"));
288 mtx_lock_spin(&pmc_softs_mtx);
290 if (ps->ps_ev.pm_ev_code != 0 &&
291 (ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST) < pmc_softevents) {
292 KASSERT((int)ps->ps_ev.pm_ev_code >= PMC_EV_SOFT_FIRST &&
293 (int)ps->ps_ev.pm_ev_code <= PMC_EV_SOFT_LAST,
294 ("pmc_soft_deregister: invalid event value"));
295 pmc_softs[ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST] = NULL;
298 mtx_unlock_spin(&pmc_softs_mtx);
302 pmc_soft_ev_acquire(enum pmc_event ev)
306 if (ev == 0 || (ev - PMC_EV_SOFT_FIRST) >= pmc_softevents)
309 KASSERT((int)ev >= PMC_EV_SOFT_FIRST &&
310 (int)ev <= PMC_EV_SOFT_LAST,
311 ("event out of range"));
313 mtx_lock_spin(&pmc_softs_mtx);
315 ps = pmc_softs[ev - PMC_EV_SOFT_FIRST];
317 mtx_unlock_spin(&pmc_softs_mtx);
323 pmc_soft_ev_release(struct pmc_soft *ps)
326 mtx_unlock_spin(&pmc_softs_mtx);
333 init_hwpmc(void *dummy __unused)
335 if (pmc_softevents <= 0 ||
336 pmc_softevents > PMC_EV_DYN_COUNT) {
337 (void) printf("hwpmc: tunable \"softevents\"=%d out of "
338 "range.\n", pmc_softevents);
339 pmc_softevents = PMC_EV_DYN_COUNT;
341 pmc_softs = malloc(pmc_softevents * sizeof(struct pmc_soft *), M_PMCHOOKS, M_NOWAIT|M_ZERO);
342 KASSERT(pmc_softs != NULL, ("cannot allocate soft events table"));
345 SYSINIT(hwpmc, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_hwpmc, NULL);