Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/x86/x86/tsc.c
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1 /*- 2 * Copyright (c) 1998-2003 Poul-Henning Kamp 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD: releng/10.4/sys/x86/x86/tsc.c 280973 2015-04-02 01:02:42Z jhb $"); 29 30 #include "opt_compat.h" 31 #include "opt_clock.h" 32 33 #include <sys/param.h> 34 #include <sys/bus.h> 35 #include <sys/cpu.h> 36 #include <sys/limits.h> 37 #include <sys/malloc.h> 38 #include <sys/systm.h> 39 #include <sys/sysctl.h> 40 #include <sys/time.h> 41 #include <sys/timetc.h> 42 #include <sys/kernel.h> 43 #include <sys/power.h> 44 #include <sys/smp.h> 45 #include <sys/vdso.h> 46 #include <machine/clock.h> 47 #include <machine/cputypes.h> 48 #include <machine/md_var.h> 49 #include <machine/specialreg.h> 50 #include <x86/vmware.h> 51 52 #include "cpufreq_if.h" 53 54 uint64_t tsc_freq; 55 int tsc_is_invariant; 56 int tsc_perf_stat; 57 58 static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag; 59 60 SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN, 61 &tsc_is_invariant, 0, "Indicates whether the TSC is P-state invariant"); 62 TUNABLE_INT("kern.timecounter.invariant_tsc", &tsc_is_invariant); 63 64 #ifdef SMP 65 int smp_tsc; 66 SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0, 67 "Indicates whether the TSC is safe to use in SMP mode"); 68 TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc); 69 70 int smp_tsc_adjust = 0; 71 SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc_adjust, CTLFLAG_RDTUN, 72 &smp_tsc_adjust, 0, "Try to adjust TSC on APs to match BSP"); 73 TUNABLE_INT("kern.timecounter.smp_tsc_adjust", &smp_tsc_adjust); 74 #endif 75 76 static int tsc_shift = 1; 77 SYSCTL_INT(_kern_timecounter, OID_AUTO, tsc_shift, CTLFLAG_RDTUN, 78 &tsc_shift, 0, "Shift to pre-apply for the maximum TSC frequency"); 79 TUNABLE_INT("kern.timecounter.tsc_shift", &tsc_shift); 80 81 static int tsc_disabled; 82 SYSCTL_INT(_machdep, OID_AUTO, disable_tsc, CTLFLAG_RDTUN, &tsc_disabled, 0, 83 "Disable x86 Time Stamp Counter"); 84 TUNABLE_INT("machdep.disable_tsc", &tsc_disabled); 85 86 static int tsc_skip_calibration; 87 SYSCTL_INT(_machdep, OID_AUTO, disable_tsc_calibration, CTLFLAG_RDTUN, 88 &tsc_skip_calibration, 0, "Disable TSC frequency calibration"); 89 TUNABLE_INT("machdep.disable_tsc_calibration", &tsc_skip_calibration); 90 91 static void tsc_freq_changed(void *arg, const struct cf_level *level, 92 int status); 93 static void tsc_freq_changing(void *arg, const struct cf_level *level, 94 int *status); 95 static unsigned tsc_get_timecount(struct timecounter *tc); 96 static inline unsigned tsc_get_timecount_low(struct timecounter *tc); 97 static unsigned tsc_get_timecount_lfence(struct timecounter *tc); 98 static unsigned tsc_get_timecount_low_lfence(struct timecounter *tc); 99 static unsigned tsc_get_timecount_mfence(struct timecounter *tc); 100 static unsigned tsc_get_timecount_low_mfence(struct timecounter *tc); 101 static void tsc_levels_changed(void *arg, int unit); 102 103 static struct timecounter tsc_timecounter = { 104 tsc_get_timecount, /* get_timecount */ 105 0, /* no poll_pps */ 106 ~0u, /* counter_mask */ 107 0, /* frequency */ 108 "TSC", /* name */ 109 800, /* quality (adjusted in code) */ 110 }; 111 112 static void 113 tsc_freq_vmware(void) 114 { 115 u_int regs[4]; 116 117 if (hv_high >= 0x40000010) { 118 do_cpuid(0x40000010, regs); 119 tsc_freq = regs[0] * 1000; 120 } else { 121 vmware_hvcall(VMW_HVCMD_GETHZ, regs); 122 if (regs[1] != UINT_MAX) 123 tsc_freq = regs[0] | ((uint64_t)regs[1] << 32); 124 } 125 tsc_is_invariant = 1; 126 } 127 128 static void 129 tsc_freq_intel(void) 130 { 131 char brand[48]; 132 u_int regs[4]; 133 uint64_t freq; 134 char *p; 135 u_int i; 136 137 /* 138 * Intel Processor Identification and the CPUID Instruction 139 * Application Note 485. 140 * http://www.intel.com/assets/pdf/appnote/241618.pdf 141 */ 142 if (cpu_exthigh >= 0x80000004) { 143 p = brand; 144 for (i = 0x80000002; i < 0x80000005; i++) { 145 do_cpuid(i, regs); 146 memcpy(p, regs, sizeof(regs)); 147 p += sizeof(regs); 148 } 149 p = NULL; 150 for (i = 0; i < sizeof(brand) - 1; i++) 151 if (brand[i] == 'H' && brand[i + 1] == 'z') 152 p = brand + i; 153 if (p != NULL) { 154 p -= 5; 155 switch (p[4]) { 156 case 'M': 157 i = 1; 158 break; 159 case 'G': 160 i = 1000; 161 break; 162 case 'T': 163 i = 1000000; 164 break; 165 default: 166 return; 167 } 168 #define C2D(c) ((c) - '') 169 if (p[1] == '.') { 170 freq = C2D(p[0]) * 1000; 171 freq += C2D(p[2]) * 100; 172 freq += C2D(p[3]) * 10; 173 freq *= i * 1000; 174 } else { 175 freq = C2D(p[0]) * 1000; 176 freq += C2D(p[1]) * 100; 177 freq += C2D(p[2]) * 10; 178 freq += C2D(p[3]); 179 freq *= i * 1000000; 180 } 181 #undef C2D 182 tsc_freq = freq; 183 } 184 } 185 } 186 187 static void 188 probe_tsc_freq(void) 189 { 190 u_int regs[4]; 191 uint64_t tsc1, tsc2; 192 193 if (cpu_high >= 6) { 194 do_cpuid(6, regs); 195 if ((regs[2] & CPUID_PERF_STAT) != 0) { 196 /* 197 * XXX Some emulators expose host CPUID without actual 198 * support for these MSRs. We must test whether they 199 * really work. 200 */ 201 wrmsr(MSR_MPERF, 0); 202 wrmsr(MSR_APERF, 0); 203 DELAY(10); 204 if (rdmsr(MSR_MPERF) > 0 && rdmsr(MSR_APERF) > 0) 205 tsc_perf_stat = 1; 206 } 207 } 208 209 if (vm_guest == VM_GUEST_VMWARE) { 210 tsc_freq_vmware(); 211 return; 212 } 213 214 switch (cpu_vendor_id) { 215 case CPU_VENDOR_AMD: 216 if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || 217 (vm_guest == VM_GUEST_NO && 218 CPUID_TO_FAMILY(cpu_id) >= 0x10)) 219 tsc_is_invariant = 1; 220 if (cpu_feature & CPUID_SSE2) { 221 tsc_timecounter.tc_get_timecount = 222 tsc_get_timecount_mfence; 223 } 224 break; 225 case CPU_VENDOR_INTEL: 226 if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || 227 (vm_guest == VM_GUEST_NO && 228 ((CPUID_TO_FAMILY(cpu_id) == 0x6 && 229 CPUID_TO_MODEL(cpu_id) >= 0xe) || 230 (CPUID_TO_FAMILY(cpu_id) == 0xf && 231 CPUID_TO_MODEL(cpu_id) >= 0x3)))) 232 tsc_is_invariant = 1; 233 if (cpu_feature & CPUID_SSE2) { 234 tsc_timecounter.tc_get_timecount = 235 tsc_get_timecount_lfence; 236 } 237 break; 238 case CPU_VENDOR_CENTAUR: 239 if (vm_guest == VM_GUEST_NO && 240 CPUID_TO_FAMILY(cpu_id) == 0x6 && 241 CPUID_TO_MODEL(cpu_id) >= 0xf && 242 (rdmsr(0x1203) & 0x100000000ULL) == 0) 243 tsc_is_invariant = 1; 244 if (cpu_feature & CPUID_SSE2) { 245 tsc_timecounter.tc_get_timecount = 246 tsc_get_timecount_lfence; 247 } 248 break; 249 } 250 251 if (tsc_skip_calibration) { 252 if (cpu_vendor_id == CPU_VENDOR_INTEL) 253 tsc_freq_intel(); 254 return; 255 } 256 257 if (bootverbose) 258 printf("Calibrating TSC clock ... "); 259 tsc1 = rdtsc(); 260 DELAY(1000000); 261 tsc2 = rdtsc(); 262 tsc_freq = tsc2 - tsc1; 263 if (bootverbose) 264 printf("TSC clock: %ju Hz\n", (intmax_t)tsc_freq); 265 } 266 267 void 268 init_TSC(void) 269 { 270 271 if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) 272 return; 273 274 #ifdef __i386__ 275 /* The TSC is known to be broken on certain CPUs. */ 276 switch (cpu_vendor_id) { 277 case CPU_VENDOR_AMD: 278 switch (cpu_id & 0xFF0) { 279 case 0x500: 280 /* K5 Model 0 */ 281 return; 282 } 283 break; 284 case CPU_VENDOR_CENTAUR: 285 switch (cpu_id & 0xff0) { 286 case 0x540: 287 /* 288 * http://www.centtech.com/c6_data_sheet.pdf 289 * 290 * I-12 RDTSC may return incoherent values in EDX:EAX 291 * I-13 RDTSC hangs when certain event counters are used 292 */ 293 return; 294 } 295 break; 296 case CPU_VENDOR_NSC: 297 switch (cpu_id & 0xff0) { 298 case 0x540: 299 if ((cpu_id & CPUID_STEPPING) == 0) 300 return; 301 break; 302 } 303 break; 304 } 305 #endif 306 307 probe_tsc_freq(); 308 309 /* 310 * Inform CPU accounting about our boot-time clock rate. This will 311 * be updated if someone loads a cpufreq driver after boot that 312 * discovers a new max frequency. 313 */ 314 if (tsc_freq != 0) 315 set_cputicker(rdtsc, tsc_freq, !tsc_is_invariant); 316 317 if (tsc_is_invariant) 318 return; 319 320 /* Register to find out about changes in CPU frequency. */ 321 tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change, 322 tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST); 323 tsc_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change, 324 tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST); 325 tsc_levels_tag = EVENTHANDLER_REGISTER(cpufreq_levels_changed, 326 tsc_levels_changed, NULL, EVENTHANDLER_PRI_ANY); 327 } 328 329 #ifdef SMP 330 331 /* 332 * RDTSC is not a serializing instruction, and does not drain 333 * instruction stream, so we need to drain the stream before executing 334 * it. It could be fixed by use of RDTSCP, except the instruction is 335 * not available everywhere. 336 * 337 * Use CPUID for draining in the boot-time SMP constistency test. The 338 * timecounters use MFENCE for AMD CPUs, and LFENCE for others (Intel 339 * and VIA) when SSE2 is present, and nothing on older machines which 340 * also do not issue RDTSC prematurely. There, testing for SSE2 and 341 * vendor is too cumbersome, and we learn about TSC presence from CPUID. 342 * 343 * Do not use do_cpuid(), since we do not need CPUID results, which 344 * have to be written into memory with do_cpuid(). 345 */ 346 #define TSC_READ(x) \ 347 static void \ 348 tsc_read_##x(void *arg) \ 349 { \ 350 uint64_t *tsc = arg; \ 351 u_int cpu = PCPU_GET(cpuid); \ 352 \ 353 __asm __volatile("cpuid" : : : "eax", "ebx", "ecx", "edx"); \ 354 tsc[cpu * 3 + x] = rdtsc(); \ 355 } 356 TSC_READ(0) 357 TSC_READ(1) 358 TSC_READ(2) 359 #undef TSC_READ 360 361 #define N 1000 362 363 static void 364 comp_smp_tsc(void *arg) 365 { 366 uint64_t *tsc; 367 int64_t d1, d2; 368 u_int cpu = PCPU_GET(cpuid); 369 u_int i, j, size; 370 371 size = (mp_maxid + 1) * 3; 372 for (i = 0, tsc = arg; i < N; i++, tsc += size) 373 CPU_FOREACH(j) { 374 if (j == cpu) 375 continue; 376 d1 = tsc[cpu * 3 + 1] - tsc[j * 3]; 377 d2 = tsc[cpu * 3 + 2] - tsc[j * 3 + 1]; 378 if (d1 <= 0 || d2 <= 0) { 379 smp_tsc = 0; 380 return; 381 } 382 } 383 } 384 385 static void 386 adj_smp_tsc(void *arg) 387 { 388 uint64_t *tsc; 389 int64_t d, min, max; 390 u_int cpu = PCPU_GET(cpuid); 391 u_int first, i, size; 392 393 first = CPU_FIRST(); 394 if (cpu == first) 395 return; 396 min = INT64_MIN; 397 max = INT64_MAX; 398 size = (mp_maxid + 1) * 3; 399 for (i = 0, tsc = arg; i < N; i++, tsc += size) { 400 d = tsc[first * 3] - tsc[cpu * 3 + 1]; 401 if (d > min) 402 min = d; 403 d = tsc[first * 3 + 1] - tsc[cpu * 3 + 2]; 404 if (d > min) 405 min = d; 406 d = tsc[first * 3 + 1] - tsc[cpu * 3]; 407 if (d < max) 408 max = d; 409 d = tsc[first * 3 + 2] - tsc[cpu * 3 + 1]; 410 if (d < max) 411 max = d; 412 } 413 if (min > max) 414 return; 415 d = min / 2 + max / 2; 416 __asm __volatile ( 417 "movl $0x10, %%ecx\n\t" 418 "rdmsr\n\t" 419 "addl %%edi, %%eax\n\t" 420 "adcl %%esi, %%edx\n\t" 421 "wrmsr\n" 422 : /* No output */ 423 : "D" ((uint32_t)d), "S" ((uint32_t)(d >> 32)) 424 : "ax", "cx", "dx", "cc" 425 ); 426 } 427 428 static int 429 test_tsc(void) 430 { 431 uint64_t *data, *tsc; 432 u_int i, size, adj; 433 434 if ((!smp_tsc && !tsc_is_invariant) || vm_guest) 435 return (-100); 436 size = (mp_maxid + 1) * 3; 437 data = malloc(sizeof(*data) * size * N, M_TEMP, M_WAITOK); 438 adj = 0; 439 retry: 440 for (i = 0, tsc = data; i < N; i++, tsc += size) 441 smp_rendezvous(tsc_read_0, tsc_read_1, tsc_read_2, tsc); 442 smp_tsc = 1; /* XXX */ 443 smp_rendezvous(smp_no_rendevous_barrier, comp_smp_tsc, 444 smp_no_rendevous_barrier, data); 445 if (!smp_tsc && adj < smp_tsc_adjust) { 446 adj++; 447 smp_rendezvous(smp_no_rendevous_barrier, adj_smp_tsc, 448 smp_no_rendevous_barrier, data); 449 goto retry; 450 } 451 free(data, M_TEMP); 452 if (bootverbose) 453 printf("SMP: %sed TSC synchronization test%s\n", 454 smp_tsc ? "pass" : "fail", 455 adj > 0 ? " after adjustment" : ""); 456 if (smp_tsc && tsc_is_invariant) { 457 switch (cpu_vendor_id) { 458 case CPU_VENDOR_AMD: 459 /* 460 * Starting with Family 15h processors, TSC clock 461 * source is in the north bridge. Check whether 462 * we have a single-socket/multi-core platform. 463 * XXX Need more work for complex cases. 464 */ 465 if (CPUID_TO_FAMILY(cpu_id) < 0x15 || 466 (amd_feature2 & AMDID2_CMP) == 0 || 467 smp_cpus > (cpu_procinfo2 & AMDID_CMP_CORES) + 1) 468 break; 469 return (1000); 470 case CPU_VENDOR_INTEL: 471 /* 472 * XXX Assume Intel platforms have synchronized TSCs. 473 */ 474 return (1000); 475 } 476 return (800); 477 } 478 return (-100); 479 } 480 481 #undef N 482 483 #else 484 485 /* 486 * The function is not called, it is provided to avoid linking failure 487 * on uniprocessor kernel. 488 */ 489 static int 490 test_tsc(void) 491 { 492 493 return (0); 494 } 495 496 #endif /* SMP */ 497 498 static void 499 init_TSC_tc(void) 500 { 501 uint64_t max_freq; 502 int shift; 503 504 if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) 505 return; 506 507 /* 508 * Limit timecounter frequency to fit in an int and prevent it from 509 * overflowing too fast. 510 */ 511 max_freq = UINT_MAX; 512 513 /* 514 * We can not use the TSC if we support APM. Precise timekeeping 515 * on an APM'ed machine is at best a fools pursuit, since 516 * any and all of the time spent in various SMM code can't 517 * be reliably accounted for. Reading the RTC is your only 518 * source of reliable time info. The i8254 loses too, of course, 519 * but we need to have some kind of time... 520 * We don't know at this point whether APM is going to be used 521 * or not, nor when it might be activated. Play it safe. 522 */ 523 if (power_pm_get_type() == POWER_PM_TYPE_APM) { 524 tsc_timecounter.tc_quality = -1000; 525 if (bootverbose) 526 printf("TSC timecounter disabled: APM enabled.\n"); 527 goto init; 528 } 529 530 /* 531 * We cannot use the TSC if it stops incrementing while idle. 532 * Intel CPUs without a C-state invariant TSC can stop the TSC 533 * in either C2 or C3. 534 */ 535 if (cpu_deepest_sleep >= 2 && cpu_vendor_id == CPU_VENDOR_INTEL && 536 (amd_pminfo & AMDPM_TSC_INVARIANT) == 0) { 537 tsc_timecounter.tc_quality = -1000; 538 tsc_timecounter.tc_flags |= TC_FLAGS_C2STOP; 539 if (bootverbose) 540 printf("TSC timecounter disabled: C2/C3 may halt it.\n"); 541 goto init; 542 } 543 544 /* 545 * We can not use the TSC in SMP mode unless the TSCs on all CPUs 546 * are synchronized. If the user is sure that the system has 547 * synchronized TSCs, set kern.timecounter.smp_tsc tunable to a 548 * non-zero value. The TSC seems unreliable in virtualized SMP 549 * environments, so it is set to a negative quality in those cases. 550 */ 551 if (mp_ncpus > 1) 552 tsc_timecounter.tc_quality = test_tsc(); 553 else if (tsc_is_invariant) 554 tsc_timecounter.tc_quality = 1000; 555 max_freq >>= tsc_shift; 556 557 init: 558 for (shift = 0; shift <= 31 && (tsc_freq >> shift) > max_freq; shift++) 559 ; 560 if ((cpu_feature & CPUID_SSE2) != 0 && mp_ncpus > 1) { 561 if (cpu_vendor_id == CPU_VENDOR_AMD) { 562 tsc_timecounter.tc_get_timecount = shift > 0 ? 563 tsc_get_timecount_low_mfence : 564 tsc_get_timecount_mfence; 565 } else { 566 tsc_timecounter.tc_get_timecount = shift > 0 ? 567 tsc_get_timecount_low_lfence : 568 tsc_get_timecount_lfence; 569 } 570 } else { 571 tsc_timecounter.tc_get_timecount = shift > 0 ? 572 tsc_get_timecount_low : tsc_get_timecount; 573 } 574 if (shift > 0) { 575 tsc_timecounter.tc_name = "TSC-low"; 576 if (bootverbose) 577 printf("TSC timecounter discards lower %d bit(s)\n", 578 shift); 579 } 580 if (tsc_freq != 0) { 581 tsc_timecounter.tc_frequency = tsc_freq >> shift; 582 tsc_timecounter.tc_priv = (void *)(intptr_t)shift; 583 tc_init(&tsc_timecounter); 584 } 585 } 586 SYSINIT(tsc_tc, SI_SUB_SMP, SI_ORDER_ANY, init_TSC_tc, NULL); 587 588 /* 589 * When cpufreq levels change, find out about the (new) max frequency. We 590 * use this to update CPU accounting in case it got a lower estimate at boot. 591 */ 592 static void 593 tsc_levels_changed(void *arg, int unit) 594 { 595 device_t cf_dev; 596 struct cf_level *levels; 597 int count, error; 598 uint64_t max_freq; 599 600 /* Only use values from the first CPU, assuming all are equal. */ 601 if (unit != 0) 602 return; 603 604 /* Find the appropriate cpufreq device instance. */ 605 cf_dev = devclass_get_device(devclass_find("cpufreq"), unit); 606 if (cf_dev == NULL) { 607 printf("tsc_levels_changed() called but no cpufreq device?\n"); 608 return; 609 } 610 611 /* Get settings from the device and find the max frequency. */ 612 count = 64; 613 levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT); 614 if (levels == NULL) 615 return; 616 error = CPUFREQ_LEVELS(cf_dev, levels, &count); 617 if (error == 0 && count != 0) { 618 max_freq = (uint64_t)levels[0].total_set.freq * 1000000; 619 set_cputicker(rdtsc, max_freq, 1); 620 } else 621 printf("tsc_levels_changed: no max freq found\n"); 622 free(levels, M_TEMP); 623 } 624 625 /* 626 * If the TSC timecounter is in use, veto the pending change. It may be 627 * possible in the future to handle a dynamically-changing timecounter rate. 628 */ 629 static void 630 tsc_freq_changing(void *arg, const struct cf_level *level, int *status) 631 { 632 633 if (*status != 0 || timecounter != &tsc_timecounter) 634 return; 635 636 printf("timecounter TSC must not be in use when " 637 "changing frequencies; change denied\n"); 638 *status = EBUSY; 639 } 640 641 /* Update TSC freq with the value indicated by the caller. */ 642 static void 643 tsc_freq_changed(void *arg, const struct cf_level *level, int status) 644 { 645 uint64_t freq; 646 647 /* If there was an error during the transition, don't do anything. */ 648 if (tsc_disabled || status != 0) 649 return; 650 651 /* Total setting for this level gives the new frequency in MHz. */ 652 freq = (uint64_t)level->total_set.freq * 1000000; 653 atomic_store_rel_64(&tsc_freq, freq); 654 tsc_timecounter.tc_frequency = 655 freq >> (int)(intptr_t)tsc_timecounter.tc_priv; 656 } 657 658 static int 659 sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS) 660 { 661 int error; 662 uint64_t freq; 663 664 freq = atomic_load_acq_64(&tsc_freq); 665 if (freq == 0) 666 return (EOPNOTSUPP); 667 error = sysctl_handle_64(oidp, &freq, 0, req); 668 if (error == 0 && req->newptr != NULL) { 669 atomic_store_rel_64(&tsc_freq, freq); 670 atomic_store_rel_64(&tsc_timecounter.tc_frequency, 671 freq >> (int)(intptr_t)tsc_timecounter.tc_priv); 672 } 673 return (error); 674 } 675 676 SYSCTL_PROC(_machdep, OID_AUTO, tsc_freq, CTLTYPE_U64 | CTLFLAG_RW, 677 0, 0, sysctl_machdep_tsc_freq, "QU", "Time Stamp Counter frequency"); 678 679 static u_int 680 tsc_get_timecount(struct timecounter *tc __unused) 681 { 682 683 return (rdtsc32()); 684 } 685 686 static inline u_int 687 tsc_get_timecount_low(struct timecounter *tc) 688 { 689 uint32_t rv; 690 691 __asm __volatile("rdtsc; shrd %%cl, %%edx, %0" 692 : "=a" (rv) : "c" ((int)(intptr_t)tc->tc_priv) : "edx"); 693 return (rv); 694 } 695 696 static u_int 697 tsc_get_timecount_lfence(struct timecounter *tc __unused) 698 { 699 700 lfence(); 701 return (rdtsc32()); 702 } 703 704 static u_int 705 tsc_get_timecount_low_lfence(struct timecounter *tc) 706 { 707 708 lfence(); 709 return (tsc_get_timecount_low(tc)); 710 } 711 712 static u_int 713 tsc_get_timecount_mfence(struct timecounter *tc __unused) 714 { 715 716 mfence(); 717 return (rdtsc32()); 718 } 719 720 static u_int 721 tsc_get_timecount_low_mfence(struct timecounter *tc) 722 { 723 724 mfence(); 725 return (tsc_get_timecount_low(tc)); 726 } 727 728 uint32_t 729 cpu_fill_vdso_timehands(struct vdso_timehands *vdso_th) 730 { 731 732 vdso_th->th_x86_shift = (int)(intptr_t)timecounter->tc_priv; 733 bzero(vdso_th->th_res, sizeof(vdso_th->th_res)); 734 return (timecounter == &tsc_timecounter); 735 } 736 737 #ifdef COMPAT_FREEBSD32 738 uint32_t 739 cpu_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32) 740 { 741 742 vdso_th32->th_x86_shift = (int)(intptr_t)timecounter->tc_priv; 743 bzero(vdso_th32->th_res, sizeof(vdso_th32->th_res)); 744 return (timecounter == &tsc_timecounter); 745 } 746 #endif
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