1 /*- 2 * Copyright (c) 2003-2008 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/ctype.h> 38 #include <sys/param.h> 39 #include <sys/malloc.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/pmc.h> 44 #include <sys/pmckern.h> 45 #include <sys/smp.h> 46 #include <sys/sysctl.h> 47 #include <sys/systm.h> 48 49 #ifdef HWPMC_HOOKS 50 FEATURE(hwpmc_hooks, "Kernel support for HW PMC"); 51 #define PMC_KERNEL_VERSION PMC_VERSION 52 #else 53 #define PMC_KERNEL_VERSION 0 54 #endif 55 56 MALLOC_DECLARE(M_PMCHOOKS); 57 MALLOC_DEFINE(M_PMCHOOKS, "pmchooks", "Memory space for PMC hooks"); 58 59 const int pmc_kernel_version = PMC_KERNEL_VERSION; 60 61 /* Hook variable. */ 62 int (*pmc_hook)(struct thread *td, int function, void *arg) = NULL; 63 64 /* Interrupt handler */ 65 int (*pmc_intr)(int cpu, struct trapframe *tf) = NULL; 66 67 /* Bitmask of CPUs requiring servicing at hardclock time */ 68 volatile cpuset_t pmc_cpumask; 69 70 /* 71 * A global count of SS mode PMCs. When non-zero, this means that 72 * we have processes that are sampling the system as a whole. 73 */ 74 volatile int pmc_ss_count; 75 76 /* 77 * Since PMC(4) may not be loaded in the current kernel, the 78 * convention followed is that a non-NULL value of 'pmc_hook' implies 79 * the presence of this kernel module. 80 * 81 * This requires us to protect 'pmc_hook' with a 82 * shared (sx) lock -- thus making the process of calling into PMC(4) 83 * somewhat more expensive than a simple 'if' check and indirect call. 84 */ 85 struct sx pmc_sx; 86 87 /* 88 * PMC Soft per cpu trapframe. 89 */ 90 struct trapframe pmc_tf[MAXCPU]; 91 92 /* 93 * PMC Soft use a global table to store registered events. 94 */ 95 96 SYSCTL_NODE(_kern, OID_AUTO, hwpmc, CTLFLAG_RW, 0, "HWPMC parameters"); 97 98 static int pmc_softevents = 16; 99 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "softevents", &pmc_softevents); 100 SYSCTL_INT(_kern_hwpmc, OID_AUTO, softevents, CTLFLAG_TUN|CTLFLAG_RD, 101 &pmc_softevents, 0, "maximum number of soft events"); 102 103 struct mtx pmc_softs_mtx; 104 int pmc_softs_count; 105 struct pmc_soft **pmc_softs; 106 107 MTX_SYSINIT(pmc_soft_mtx, &pmc_softs_mtx, "pmc-softs", MTX_SPIN); 108 109 static void 110 pmc_init_sx(void) 111 { 112 sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS); 113 } 114 115 SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL); 116 117 /* 118 * Helper functions. 119 */ 120 121 /* 122 * A note on the CPU numbering scheme used by the hwpmc(4) driver. 123 * 124 * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1]. 125 * CPUs could be numbered "sparsely" in this range; the predicate 126 * `pmc_cpu_is_present()' is used to test whether a given CPU is 127 * physically present. 128 * 129 * Further, a CPU that is physically present may be administratively 130 * disabled or otherwise unavailable for use by hwpmc(4). The 131 * `pmc_cpu_is_active()' predicate tests for CPU usability. An 132 * "active" CPU participates in thread scheduling and can field 133 * interrupts raised by PMC hardware. 134 * 135 * On systems with hyperthreaded CPUs, multiple logical CPUs may share 136 * PMC hardware resources. For such processors one logical CPU is 137 * denoted as the primary owner of the in-CPU PMC resources. The 138 * pmc_cpu_is_primary() predicate is used to distinguish this primary 139 * CPU from the others. 140 */ 141 142 int 143 pmc_cpu_is_active(int cpu) 144 { 145 #ifdef SMP 146 return (pmc_cpu_is_present(cpu) && 147 !CPU_ISSET(cpu, &hlt_cpus_mask)); 148 #else 149 return (1); 150 #endif 151 } 152 153 /* Deprecated. */ 154 int 155 pmc_cpu_is_disabled(int cpu) 156 { 157 return (!pmc_cpu_is_active(cpu)); 158 } 159 160 int 161 pmc_cpu_is_present(int cpu) 162 { 163 #ifdef SMP 164 return (!CPU_ABSENT(cpu)); 165 #else 166 return (1); 167 #endif 168 } 169 170 int 171 pmc_cpu_is_primary(int cpu) 172 { 173 #ifdef SMP 174 return (!CPU_ISSET(cpu, &logical_cpus_mask)); 175 #else 176 return (1); 177 #endif 178 } 179 180 181 /* 182 * Return the maximum CPU number supported by the system. The return 183 * value is used for scaling internal data structures and for runtime 184 * checks. 185 */ 186 unsigned int 187 pmc_cpu_max(void) 188 { 189 #ifdef SMP 190 return (mp_maxid+1); 191 #else 192 return (1); 193 #endif 194 } 195 196 #ifdef INVARIANTS 197 198 /* 199 * Return the count of CPUs in the `active' state in the system. 200 */ 201 int 202 pmc_cpu_max_active(void) 203 { 204 #ifdef SMP 205 /* 206 * When support for CPU hot-plugging is added to the kernel, 207 * this function would change to return the current number 208 * of "active" CPUs. 209 */ 210 return (mp_ncpus); 211 #else 212 return (1); 213 #endif 214 } 215 216 #endif 217 218 /* 219 * Cleanup event name: 220 * - remove duplicate '_' 221 * - all uppercase 222 */ 223 static void 224 pmc_soft_namecleanup(char *name) 225 { 226 char *p, *q; 227 228 p = q = name; 229 230 for ( ; *p == '_' ; p++) 231 ; 232 for ( ; *p ; p++) { 233 if (*p == '_' && (*(p + 1) == '_' || *(p + 1) == '\0')) 234 continue; 235 else 236 *q++ = toupper(*p); 237 } 238 *q = '\0'; 239 } 240 241 void 242 pmc_soft_ev_register(struct pmc_soft *ps) 243 { 244 static int warned = 0; 245 int n; 246 247 ps->ps_running = 0; 248 ps->ps_ev.pm_ev_code = 0; /* invalid */ 249 pmc_soft_namecleanup(ps->ps_ev.pm_ev_name); 250 251 mtx_lock_spin(&pmc_softs_mtx); 252 253 if (pmc_softs_count >= pmc_softevents) { 254 /* 255 * XXX Reusing events can enter a race condition where 256 * new allocated event will be used as an old one. 257 */ 258 for (n = 0; n < pmc_softevents; n++) 259 if (pmc_softs[n] == NULL) 260 break; 261 if (n == pmc_softevents) { 262 mtx_unlock_spin(&pmc_softs_mtx); 263 if (!warned) { 264 printf("hwpmc: too many soft events, " 265 "increase kern.hwpmc.softevents tunable\n"); 266 warned = 1; 267 } 268 return; 269 } 270 271 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + n; 272 pmc_softs[n] = ps; 273 } else { 274 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + pmc_softs_count; 275 pmc_softs[pmc_softs_count++] = ps; 276 } 277 278 mtx_unlock_spin(&pmc_softs_mtx); 279 } 280 281 void 282 pmc_soft_ev_deregister(struct pmc_soft *ps) 283 { 284 285 KASSERT(ps != NULL, ("pmc_soft_deregister: called with NULL")); 286 287 mtx_lock_spin(&pmc_softs_mtx); 288 289 if (ps->ps_ev.pm_ev_code != 0 && 290 (ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST) < pmc_softevents) { 291 KASSERT(ps->ps_ev.pm_ev_code >= PMC_EV_SOFT_FIRST && 292 ps->ps_ev.pm_ev_code <= PMC_EV_SOFT_LAST, 293 ("pmc_soft_deregister: invalid event value")); 294 pmc_softs[ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST] = NULL; 295 } 296 297 mtx_unlock_spin(&pmc_softs_mtx); 298 } 299 300 struct pmc_soft * 301 pmc_soft_ev_acquire(enum pmc_event ev) 302 { 303 struct pmc_soft *ps; 304 305 if (ev == 0 || (ev - PMC_EV_SOFT_FIRST) >= pmc_softevents) 306 return NULL; 307 308 KASSERT(ev >= PMC_EV_SOFT_FIRST && 309 ev <= PMC_EV_SOFT_LAST, 310 ("event out of range")); 311 312 mtx_lock_spin(&pmc_softs_mtx); 313 314 ps = pmc_softs[ev - PMC_EV_SOFT_FIRST]; 315 if (ps == NULL) 316 mtx_unlock_spin(&pmc_softs_mtx); 317 318 return ps; 319 } 320 321 void 322 pmc_soft_ev_release(struct pmc_soft *ps) 323 { 324 325 mtx_unlock_spin(&pmc_softs_mtx); 326 } 327 328 /* 329 * Initialise hwpmc. 330 */ 331 static void 332 init_hwpmc(void *dummy __unused) 333 { 334 if (pmc_softevents <= 0 || 335 pmc_softevents > PMC_EV_DYN_COUNT) { 336 (void) printf("hwpmc: tunable \"softevents\"=%d out of " 337 "range.\n", pmc_softevents); 338 pmc_softevents = PMC_EV_DYN_COUNT; 339 } 340 pmc_softs = malloc(pmc_softevents * sizeof(struct pmc_soft *), M_PMCHOOKS, M_NOWAIT|M_ZERO); 341 KASSERT(pmc_softs != NULL, ("cannot allocate soft events table")); 342 } 343 344 SYSINIT(hwpmc, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_hwpmc, NULL); 345 346