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 SYSCTL_INT(_kern_hwpmc, OID_AUTO, softevents, CTLFLAG_RDTUN, 100 &pmc_softevents, 0, "maximum number of soft events"); 101 102 struct mtx pmc_softs_mtx; 103 int pmc_softs_count; 104 struct pmc_soft **pmc_softs; 105 106 MTX_SYSINIT(pmc_soft_mtx, &pmc_softs_mtx, "pmc-softs", MTX_SPIN); 107 108 static void 109 pmc_init_sx(void) 110 { 111 sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS); 112 } 113 114 SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL); 115 116 /* 117 * Helper functions. 118 */ 119 120 /* 121 * A note on the CPU numbering scheme used by the hwpmc(4) driver. 122 * 123 * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1]. 124 * CPUs could be numbered "sparsely" in this range; the predicate 125 * `pmc_cpu_is_present()' is used to test whether a given CPU is 126 * physically present. 127 * 128 * Further, a CPU that is physically present may be administratively 129 * disabled or otherwise unavailable for use by hwpmc(4). The 130 * `pmc_cpu_is_active()' predicate tests for CPU usability. An 131 * "active" CPU participates in thread scheduling and can field 132 * interrupts raised by PMC hardware. 133 * 134 * On systems with hyperthreaded CPUs, multiple logical CPUs may share 135 * PMC hardware resources. For such processors one logical CPU is 136 * denoted as the primary owner of the in-CPU PMC resources. The 137 * pmc_cpu_is_primary() predicate is used to distinguish this primary 138 * CPU from the others. 139 */ 140 141 int 142 pmc_cpu_is_active(int cpu) 143 { 144 #ifdef SMP 145 return (pmc_cpu_is_present(cpu) && 146 !CPU_ISSET(cpu, &hlt_cpus_mask)); 147 #else 148 return (1); 149 #endif 150 } 151 152 /* Deprecated. */ 153 int 154 pmc_cpu_is_disabled(int cpu) 155 { 156 return (!pmc_cpu_is_active(cpu)); 157 } 158 159 int 160 pmc_cpu_is_present(int cpu) 161 { 162 #ifdef SMP 163 return (!CPU_ABSENT(cpu)); 164 #else 165 return (1); 166 #endif 167 } 168 169 int 170 pmc_cpu_is_primary(int cpu) 171 { 172 #ifdef SMP 173 return (!CPU_ISSET(cpu, &logical_cpus_mask)); 174 #else 175 return (1); 176 #endif 177 } 178 179 180 /* 181 * Return the maximum CPU number supported by the system. The return 182 * value is used for scaling internal data structures and for runtime 183 * checks. 184 */ 185 unsigned int 186 pmc_cpu_max(void) 187 { 188 #ifdef SMP 189 return (mp_maxid+1); 190 #else 191 return (1); 192 #endif 193 } 194 195 #ifdef INVARIANTS 196 197 /* 198 * Return the count of CPUs in the `active' state in the system. 199 */ 200 int 201 pmc_cpu_max_active(void) 202 { 203 #ifdef SMP 204 /* 205 * When support for CPU hot-plugging is added to the kernel, 206 * this function would change to return the current number 207 * of "active" CPUs. 208 */ 209 return (mp_ncpus); 210 #else 211 return (1); 212 #endif 213 } 214 215 #endif 216 217 /* 218 * Cleanup event name: 219 * - remove duplicate '_' 220 * - all uppercase 221 */ 222 static void 223 pmc_soft_namecleanup(char *name) 224 { 225 char *p, *q; 226 227 p = q = name; 228 229 for ( ; *p == '_' ; p++) 230 ; 231 for ( ; *p ; p++) { 232 if (*p == '_' && (*(p + 1) == '_' || *(p + 1) == '\0')) 233 continue; 234 else 235 *q++ = toupper(*p); 236 } 237 *q = '\0'; 238 } 239 240 void 241 pmc_soft_ev_register(struct pmc_soft *ps) 242 { 243 static int warned = 0; 244 int n; 245 246 ps->ps_running = 0; 247 ps->ps_ev.pm_ev_code = 0; /* invalid */ 248 pmc_soft_namecleanup(ps->ps_ev.pm_ev_name); 249 250 mtx_lock_spin(&pmc_softs_mtx); 251 252 if (pmc_softs_count >= pmc_softevents) { 253 /* 254 * XXX Reusing events can enter a race condition where 255 * new allocated event will be used as an old one. 256 */ 257 for (n = 0; n < pmc_softevents; n++) 258 if (pmc_softs[n] == NULL) 259 break; 260 if (n == pmc_softevents) { 261 mtx_unlock_spin(&pmc_softs_mtx); 262 if (!warned) { 263 printf("hwpmc: too many soft events, " 264 "increase kern.hwpmc.softevents tunable\n"); 265 warned = 1; 266 } 267 return; 268 } 269 270 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + n; 271 pmc_softs[n] = ps; 272 } else { 273 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + pmc_softs_count; 274 pmc_softs[pmc_softs_count++] = ps; 275 } 276 277 mtx_unlock_spin(&pmc_softs_mtx); 278 } 279 280 void 281 pmc_soft_ev_deregister(struct pmc_soft *ps) 282 { 283 284 KASSERT(ps != NULL, ("pmc_soft_deregister: called with NULL")); 285 286 mtx_lock_spin(&pmc_softs_mtx); 287 288 if (ps->ps_ev.pm_ev_code != 0 && 289 (ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST) < pmc_softevents) { 290 KASSERT(ps->ps_ev.pm_ev_code >= PMC_EV_SOFT_FIRST && 291 ps->ps_ev.pm_ev_code <= PMC_EV_SOFT_LAST, 292 ("pmc_soft_deregister: invalid event value")); 293 pmc_softs[ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST] = NULL; 294 } 295 296 mtx_unlock_spin(&pmc_softs_mtx); 297 } 298 299 struct pmc_soft * 300 pmc_soft_ev_acquire(enum pmc_event ev) 301 { 302 struct pmc_soft *ps; 303 304 if (ev == 0 || (ev - PMC_EV_SOFT_FIRST) >= pmc_softevents) 305 return NULL; 306 307 KASSERT(ev >= PMC_EV_SOFT_FIRST && 308 ev <= PMC_EV_SOFT_LAST, 309 ("event out of range")); 310 311 mtx_lock_spin(&pmc_softs_mtx); 312 313 ps = pmc_softs[ev - PMC_EV_SOFT_FIRST]; 314 if (ps == NULL) 315 mtx_unlock_spin(&pmc_softs_mtx); 316 317 return ps; 318 } 319 320 void 321 pmc_soft_ev_release(struct pmc_soft *ps) 322 { 323 324 mtx_unlock_spin(&pmc_softs_mtx); 325 } 326 327 /* 328 * Initialise hwpmc. 329 */ 330 static void 331 init_hwpmc(void *dummy __unused) 332 { 333 if (pmc_softevents <= 0 || 334 pmc_softevents > PMC_EV_DYN_COUNT) { 335 (void) printf("hwpmc: tunable \"softevents\"=%d out of " 336 "range.\n", pmc_softevents); 337 pmc_softevents = PMC_EV_DYN_COUNT; 338 } 339 pmc_softs = malloc(pmc_softevents * sizeof(struct pmc_soft *), M_PMCHOOKS, M_NOWAIT|M_ZERO); 340 KASSERT(pmc_softs != NULL, ("cannot allocate soft events table")); 341 } 342 343 SYSINIT(hwpmc, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_hwpmc, NULL); 344 345