1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998-2003 Poul-Henning Kamp 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_clock.h" 33 34 #include <sys/param.h> 35 #include <sys/bus.h> 36 #include <sys/cpu.h> 37 #include <sys/eventhandler.h> 38 #include <sys/limits.h> 39 #include <sys/malloc.h> 40 #include <sys/systm.h> 41 #include <sys/sysctl.h> 42 #include <sys/time.h> 43 #include <sys/timetc.h> 44 #include <sys/kernel.h> 45 #include <sys/power.h> 46 #include <sys/smp.h> 47 #include <sys/vdso.h> 48 #include <machine/clock.h> 49 #include <machine/cputypes.h> 50 #include <machine/md_var.h> 51 #include <machine/specialreg.h> 52 #include <x86/vmware.h> 53 #include <dev/acpica/acpi_hpet.h> 54 #include <contrib/dev/acpica/include/acpi.h> 55 56 #include "cpufreq_if.h" 57 58 uint64_t tsc_freq; 59 int tsc_is_invariant; 60 int tsc_perf_stat; 61 62 static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag; 63 64 SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN, 65 &tsc_is_invariant, 0, "Indicates whether the TSC is P-state invariant"); 66 67 #ifdef SMP 68 int smp_tsc; 69 SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0, 70 "Indicates whether the TSC is safe to use in SMP mode"); 71 72 int smp_tsc_adjust = 0; 73 SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc_adjust, CTLFLAG_RDTUN, 74 &smp_tsc_adjust, 0, "Try to adjust TSC on APs to match BSP"); 75 #endif 76 77 static int tsc_shift = 1; 78 SYSCTL_INT(_kern_timecounter, OID_AUTO, tsc_shift, CTLFLAG_RDTUN, 79 &tsc_shift, 0, "Shift to pre-apply for the maximum TSC frequency"); 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 85 static int tsc_skip_calibration; 86 SYSCTL_INT(_machdep, OID_AUTO, disable_tsc_calibration, CTLFLAG_RDTUN, 87 &tsc_skip_calibration, 0, 88 "Disable TSC frequency calibration"); 89 90 static void tsc_freq_changed(void *arg, const struct cf_level *level, 91 int status); 92 static void tsc_freq_changing(void *arg, const struct cf_level *level, 93 int *status); 94 static u_int tsc_get_timecount(struct timecounter *tc); 95 static inline u_int tsc_get_timecount_low(struct timecounter *tc); 96 static u_int tsc_get_timecount_lfence(struct timecounter *tc); 97 static u_int tsc_get_timecount_low_lfence(struct timecounter *tc); 98 static u_int tsc_get_timecount_mfence(struct timecounter *tc); 99 static u_int tsc_get_timecount_low_mfence(struct timecounter *tc); 100 static u_int tscp_get_timecount(struct timecounter *tc); 101 static u_int tscp_get_timecount_low(struct timecounter *tc); 102 static void tsc_levels_changed(void *arg, int unit); 103 static uint32_t x86_tsc_vdso_timehands(struct vdso_timehands *vdso_th, 104 struct timecounter *tc); 105 #ifdef COMPAT_FREEBSD32 106 static uint32_t x86_tsc_vdso_timehands32(struct vdso_timehands32 *vdso_th32, 107 struct timecounter *tc); 108 #endif 109 110 static struct timecounter tsc_timecounter = { 111 .tc_get_timecount = tsc_get_timecount, 112 .tc_counter_mask = ~0u, 113 .tc_name = "TSC", 114 .tc_quality = 800, /* adjusted in code */ 115 .tc_fill_vdso_timehands = x86_tsc_vdso_timehands, 116 #ifdef COMPAT_FREEBSD32 117 .tc_fill_vdso_timehands32 = x86_tsc_vdso_timehands32, 118 #endif 119 }; 120 121 static void 122 tsc_freq_vmware(void) 123 { 124 u_int regs[4]; 125 126 if (hv_high >= 0x40000010) { 127 do_cpuid(0x40000010, regs); 128 tsc_freq = regs[0] * 1000; 129 } else { 130 vmware_hvcall(VMW_HVCMD_GETHZ, regs); 131 if (regs[1] != UINT_MAX) 132 tsc_freq = regs[0] | ((uint64_t)regs[1] << 32); 133 } 134 tsc_is_invariant = 1; 135 } 136 137 /* 138 * Calculate TSC frequency using information from the CPUID leaf 0x15 139 * 'Time Stamp Counter and Nominal Core Crystal Clock'. If leaf 0x15 140 * is not functional, as it is on Skylake/Kabylake, try 0x16 'Processor 141 * Frequency Information'. Leaf 0x16 is described in the SDM as 142 * informational only, but if 0x15 did not work, and TSC calibration 143 * is disabled, it is the best we can get at all. It should still be 144 * an improvement over the parsing of the CPU model name in 145 * tsc_freq_intel(), when available. 146 */ 147 static bool 148 tsc_freq_cpuid(uint64_t *res) 149 { 150 u_int regs[4]; 151 152 if (cpu_high < 0x15) 153 return (false); 154 do_cpuid(0x15, regs); 155 if (regs[0] != 0 && regs[1] != 0 && regs[2] != 0) { 156 *res = (uint64_t)regs[2] * regs[1] / regs[0]; 157 return (true); 158 } 159 160 if (cpu_high < 0x16) 161 return (false); 162 do_cpuid(0x16, regs); 163 if (regs[0] != 0) { 164 *res = (uint64_t)regs[0] * 1000000; 165 return (true); 166 } 167 168 return (false); 169 } 170 171 static void 172 tsc_freq_intel(void) 173 { 174 char brand[48]; 175 u_int regs[4]; 176 uint64_t freq; 177 char *p; 178 u_int i; 179 180 /* 181 * Intel Processor Identification and the CPUID Instruction 182 * Application Note 485. 183 * http://www.intel.com/assets/pdf/appnote/241618.pdf 184 */ 185 if (cpu_exthigh >= 0x80000004) { 186 p = brand; 187 for (i = 0x80000002; i < 0x80000005; i++) { 188 do_cpuid(i, regs); 189 memcpy(p, regs, sizeof(regs)); 190 p += sizeof(regs); 191 } 192 p = NULL; 193 for (i = 0; i < sizeof(brand) - 1; i++) 194 if (brand[i] == 'H' && brand[i + 1] == 'z') 195 p = brand + i; 196 if (p != NULL) { 197 p -= 5; 198 switch (p[4]) { 199 case 'M': 200 i = 1; 201 break; 202 case 'G': 203 i = 1000; 204 break; 205 case 'T': 206 i = 1000000; 207 break; 208 default: 209 return; 210 } 211 #define C2D(c) ((c) - '0') 212 if (p[1] == '.') { 213 freq = C2D(p[0]) * 1000; 214 freq += C2D(p[2]) * 100; 215 freq += C2D(p[3]) * 10; 216 freq *= i * 1000; 217 } else { 218 freq = C2D(p[0]) * 1000; 219 freq += C2D(p[1]) * 100; 220 freq += C2D(p[2]) * 10; 221 freq += C2D(p[3]); 222 freq *= i * 1000000; 223 } 224 #undef C2D 225 tsc_freq = freq; 226 } 227 } 228 } 229 230 static void 231 probe_tsc_freq(void) 232 { 233 uint64_t tmp_freq, tsc1, tsc2; 234 int no_cpuid_override; 235 236 if (cpu_power_ecx & CPUID_PERF_STAT) { 237 /* 238 * XXX Some emulators expose host CPUID without actual support 239 * for these MSRs. We must test whether they really work. 240 */ 241 wrmsr(MSR_MPERF, 0); 242 wrmsr(MSR_APERF, 0); 243 DELAY(10); 244 if (rdmsr(MSR_MPERF) > 0 && rdmsr(MSR_APERF) > 0) 245 tsc_perf_stat = 1; 246 } 247 248 if (vm_guest == VM_GUEST_VMWARE) { 249 tsc_freq_vmware(); 250 return; 251 } 252 253 switch (cpu_vendor_id) { 254 case CPU_VENDOR_AMD: 255 case CPU_VENDOR_HYGON: 256 if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || 257 (vm_guest == VM_GUEST_NO && 258 CPUID_TO_FAMILY(cpu_id) >= 0x10)) 259 tsc_is_invariant = 1; 260 if (cpu_feature & CPUID_SSE2) { 261 tsc_timecounter.tc_get_timecount = 262 tsc_get_timecount_mfence; 263 } 264 break; 265 case CPU_VENDOR_INTEL: 266 if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || 267 (vm_guest == VM_GUEST_NO && 268 ((CPUID_TO_FAMILY(cpu_id) == 0x6 && 269 CPUID_TO_MODEL(cpu_id) >= 0xe) || 270 (CPUID_TO_FAMILY(cpu_id) == 0xf && 271 CPUID_TO_MODEL(cpu_id) >= 0x3)))) 272 tsc_is_invariant = 1; 273 if (cpu_feature & CPUID_SSE2) { 274 tsc_timecounter.tc_get_timecount = 275 tsc_get_timecount_lfence; 276 } 277 break; 278 case CPU_VENDOR_CENTAUR: 279 if (vm_guest == VM_GUEST_NO && 280 CPUID_TO_FAMILY(cpu_id) == 0x6 && 281 CPUID_TO_MODEL(cpu_id) >= 0xf && 282 (rdmsr(0x1203) & 0x100000000ULL) == 0) 283 tsc_is_invariant = 1; 284 if (cpu_feature & CPUID_SSE2) { 285 tsc_timecounter.tc_get_timecount = 286 tsc_get_timecount_lfence; 287 } 288 break; 289 } 290 291 if (tsc_skip_calibration) { 292 if (tsc_freq_cpuid(&tmp_freq)) 293 tsc_freq = tmp_freq; 294 else if (cpu_vendor_id == CPU_VENDOR_INTEL) 295 tsc_freq_intel(); 296 if (tsc_freq == 0) 297 tsc_disabled = 1; 298 } else { 299 if (bootverbose) 300 printf("Calibrating TSC clock ... "); 301 tsc1 = rdtsc(); 302 DELAY(1000000); 303 tsc2 = rdtsc(); 304 tsc_freq = tsc2 - tsc1; 305 306 /* 307 * If the difference between calibrated frequency and 308 * the frequency reported by CPUID 0x15/0x16 leafs 309 * differ significantly, this probably means that 310 * calibration is bogus. It happens on machines 311 * without 8254 timer. The BIOS rarely properly 312 * reports it in FADT boot flags, so just compare the 313 * frequencies directly. 314 */ 315 if (tsc_freq_cpuid(&tmp_freq) && qabs(tsc_freq - tmp_freq) > 316 uqmin(tsc_freq, tmp_freq)) { 317 no_cpuid_override = 0; 318 TUNABLE_INT_FETCH("machdep.disable_tsc_cpuid_override", 319 &no_cpuid_override); 320 if (!no_cpuid_override) { 321 if (bootverbose) { 322 printf( 323 "TSC clock: calibration freq %ju Hz, CPUID freq %ju Hz%s\n", 324 (uintmax_t)tsc_freq, 325 (uintmax_t)tmp_freq, 326 no_cpuid_override ? "" : 327 ", doing CPUID override"); 328 } 329 tsc_freq = tmp_freq; 330 } 331 } 332 } 333 if (bootverbose) 334 printf("TSC clock: %ju Hz\n", (intmax_t)tsc_freq); 335 } 336 337 void 338 init_TSC(void) 339 { 340 341 if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) 342 return; 343 344 #ifdef __i386__ 345 /* The TSC is known to be broken on certain CPUs. */ 346 switch (cpu_vendor_id) { 347 case CPU_VENDOR_AMD: 348 switch (cpu_id & 0xFF0) { 349 case 0x500: 350 /* K5 Model 0 */ 351 return; 352 } 353 break; 354 case CPU_VENDOR_CENTAUR: 355 switch (cpu_id & 0xff0) { 356 case 0x540: 357 /* 358 * http://www.centtech.com/c6_data_sheet.pdf 359 * 360 * I-12 RDTSC may return incoherent values in EDX:EAX 361 * I-13 RDTSC hangs when certain event counters are used 362 */ 363 return; 364 } 365 break; 366 case CPU_VENDOR_NSC: 367 switch (cpu_id & 0xff0) { 368 case 0x540: 369 if ((cpu_id & CPUID_STEPPING) == 0) 370 return; 371 break; 372 } 373 break; 374 } 375 #endif 376 377 probe_tsc_freq(); 378 379 /* 380 * Inform CPU accounting about our boot-time clock rate. This will 381 * be updated if someone loads a cpufreq driver after boot that 382 * discovers a new max frequency. 383 */ 384 if (tsc_freq != 0) 385 set_cputicker(rdtsc, tsc_freq, !tsc_is_invariant); 386 387 if (tsc_is_invariant) 388 return; 389 390 /* Register to find out about changes in CPU frequency. */ 391 tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change, 392 tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST); 393 tsc_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change, 394 tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST); 395 tsc_levels_tag = EVENTHANDLER_REGISTER(cpufreq_levels_changed, 396 tsc_levels_changed, NULL, EVENTHANDLER_PRI_ANY); 397 } 398 399 #ifdef SMP 400 401 /* 402 * RDTSC is not a serializing instruction, and does not drain 403 * instruction stream, so we need to drain the stream before executing 404 * it. It could be fixed by use of RDTSCP, except the instruction is 405 * not available everywhere. 406 * 407 * Use CPUID for draining in the boot-time SMP constistency test. The 408 * timecounters use MFENCE for AMD CPUs, and LFENCE for others (Intel 409 * and VIA) when SSE2 is present, and nothing on older machines which 410 * also do not issue RDTSC prematurely. There, testing for SSE2 and 411 * vendor is too cumbersome, and we learn about TSC presence from CPUID. 412 * 413 * Do not use do_cpuid(), since we do not need CPUID results, which 414 * have to be written into memory with do_cpuid(). 415 */ 416 #define TSC_READ(x) \ 417 static void \ 418 tsc_read_##x(void *arg) \ 419 { \ 420 uint64_t *tsc = arg; \ 421 u_int cpu = PCPU_GET(cpuid); \ 422 \ 423 __asm __volatile("cpuid" : : : "eax", "ebx", "ecx", "edx"); \ 424 tsc[cpu * 3 + x] = rdtsc(); \ 425 } 426 TSC_READ(0) 427 TSC_READ(1) 428 TSC_READ(2) 429 #undef TSC_READ 430 431 #define N 1000 432 433 static void 434 comp_smp_tsc(void *arg) 435 { 436 uint64_t *tsc; 437 int64_t d1, d2; 438 u_int cpu = PCPU_GET(cpuid); 439 u_int i, j, size; 440 441 size = (mp_maxid + 1) * 3; 442 for (i = 0, tsc = arg; i < N; i++, tsc += size) 443 CPU_FOREACH(j) { 444 if (j == cpu) 445 continue; 446 d1 = tsc[cpu * 3 + 1] - tsc[j * 3]; 447 d2 = tsc[cpu * 3 + 2] - tsc[j * 3 + 1]; 448 if (d1 <= 0 || d2 <= 0) { 449 smp_tsc = 0; 450 return; 451 } 452 } 453 } 454 455 static void 456 adj_smp_tsc(void *arg) 457 { 458 uint64_t *tsc; 459 int64_t d, min, max; 460 u_int cpu = PCPU_GET(cpuid); 461 u_int first, i, size; 462 463 first = CPU_FIRST(); 464 if (cpu == first) 465 return; 466 min = INT64_MIN; 467 max = INT64_MAX; 468 size = (mp_maxid + 1) * 3; 469 for (i = 0, tsc = arg; i < N; i++, tsc += size) { 470 d = tsc[first * 3] - tsc[cpu * 3 + 1]; 471 if (d > min) 472 min = d; 473 d = tsc[first * 3 + 1] - tsc[cpu * 3 + 2]; 474 if (d > min) 475 min = d; 476 d = tsc[first * 3 + 1] - tsc[cpu * 3]; 477 if (d < max) 478 max = d; 479 d = tsc[first * 3 + 2] - tsc[cpu * 3 + 1]; 480 if (d < max) 481 max = d; 482 } 483 if (min > max) 484 return; 485 d = min / 2 + max / 2; 486 __asm __volatile ( 487 "movl $0x10, %%ecx\n\t" 488 "rdmsr\n\t" 489 "addl %%edi, %%eax\n\t" 490 "adcl %%esi, %%edx\n\t" 491 "wrmsr\n" 492 : /* No output */ 493 : "D" ((uint32_t)d), "S" ((uint32_t)(d >> 32)) 494 : "ax", "cx", "dx", "cc" 495 ); 496 } 497 498 static int 499 test_tsc(int adj_max_count) 500 { 501 uint64_t *data, *tsc; 502 u_int i, size, adj; 503 504 if ((!smp_tsc && !tsc_is_invariant)) 505 return (-100); 506 /* 507 * Misbehavior of TSC under VirtualBox has been observed. In 508 * particular, threads doing small (~1 second) sleeps may miss their 509 * wakeup and hang around in sleep state, causing hangs on shutdown. 510 */ 511 if (vm_guest == VM_GUEST_VBOX) 512 return (0); 513 514 size = (mp_maxid + 1) * 3; 515 data = malloc(sizeof(*data) * size * N, M_TEMP, M_WAITOK); 516 adj = 0; 517 retry: 518 for (i = 0, tsc = data; i < N; i++, tsc += size) 519 smp_rendezvous(tsc_read_0, tsc_read_1, tsc_read_2, tsc); 520 smp_tsc = 1; /* XXX */ 521 smp_rendezvous(smp_no_rendezvous_barrier, comp_smp_tsc, 522 smp_no_rendezvous_barrier, data); 523 if (!smp_tsc && adj < adj_max_count) { 524 adj++; 525 smp_rendezvous(smp_no_rendezvous_barrier, adj_smp_tsc, 526 smp_no_rendezvous_barrier, data); 527 goto retry; 528 } 529 free(data, M_TEMP); 530 if (bootverbose) 531 printf("SMP: %sed TSC synchronization test%s\n", 532 smp_tsc ? "pass" : "fail", 533 adj > 0 ? " after adjustment" : ""); 534 if (smp_tsc && tsc_is_invariant) { 535 switch (cpu_vendor_id) { 536 case CPU_VENDOR_AMD: 537 case CPU_VENDOR_HYGON: 538 /* 539 * Processor Programming Reference (PPR) for AMD 540 * Family 17h states that the TSC uses a common 541 * reference for all sockets, cores and threads. 542 */ 543 if (CPUID_TO_FAMILY(cpu_id) >= 0x17) 544 return (1000); 545 /* 546 * Starting with Family 15h processors, TSC clock 547 * source is in the north bridge. Check whether 548 * we have a single-socket/multi-core platform. 549 * XXX Need more work for complex cases. 550 */ 551 if (CPUID_TO_FAMILY(cpu_id) < 0x15 || 552 (amd_feature2 & AMDID2_CMP) == 0 || 553 smp_cpus > (cpu_procinfo2 & AMDID_CMP_CORES) + 1) 554 break; 555 return (1000); 556 case CPU_VENDOR_INTEL: 557 /* 558 * XXX Assume Intel platforms have synchronized TSCs. 559 */ 560 return (1000); 561 } 562 return (800); 563 } 564 return (-100); 565 } 566 567 #undef N 568 569 #endif /* SMP */ 570 571 static void 572 init_TSC_tc(void) 573 { 574 uint64_t max_freq; 575 int shift; 576 577 if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) 578 return; 579 580 /* 581 * Limit timecounter frequency to fit in an int and prevent it from 582 * overflowing too fast. 583 */ 584 max_freq = UINT_MAX; 585 586 /* 587 * We can not use the TSC if we support APM. Precise timekeeping 588 * on an APM'ed machine is at best a fools pursuit, since 589 * any and all of the time spent in various SMM code can't 590 * be reliably accounted for. Reading the RTC is your only 591 * source of reliable time info. The i8254 loses too, of course, 592 * but we need to have some kind of time... 593 * We don't know at this point whether APM is going to be used 594 * or not, nor when it might be activated. Play it safe. 595 */ 596 if (power_pm_get_type() == POWER_PM_TYPE_APM) { 597 tsc_timecounter.tc_quality = -1000; 598 if (bootverbose) 599 printf("TSC timecounter disabled: APM enabled.\n"); 600 goto init; 601 } 602 603 /* 604 * Intel CPUs without a C-state invariant TSC can stop the TSC 605 * in either C2 or C3. Disable use of C2 and C3 while using 606 * the TSC as the timecounter. The timecounter can be changed 607 * to enable C2 and C3. 608 * 609 * Note that the TSC is used as the cputicker for computing 610 * thread runtime regardless of the timecounter setting, so 611 * using an alternate timecounter and enabling C2 or C3 can 612 * result incorrect runtimes for kernel idle threads (but not 613 * for any non-idle threads). 614 */ 615 if (cpu_vendor_id == CPU_VENDOR_INTEL && 616 (amd_pminfo & AMDPM_TSC_INVARIANT) == 0) { 617 tsc_timecounter.tc_flags |= TC_FLAGS_C2STOP; 618 if (bootverbose) 619 printf("TSC timecounter disables C2 and C3.\n"); 620 } 621 622 /* 623 * We can not use the TSC in SMP mode unless the TSCs on all CPUs 624 * are synchronized. If the user is sure that the system has 625 * synchronized TSCs, set kern.timecounter.smp_tsc tunable to a 626 * non-zero value. The TSC seems unreliable in virtualized SMP 627 * environments, so it is set to a negative quality in those cases. 628 */ 629 #ifdef SMP 630 if (mp_ncpus > 1) 631 tsc_timecounter.tc_quality = test_tsc(smp_tsc_adjust); 632 else 633 #endif /* SMP */ 634 if (tsc_is_invariant) 635 tsc_timecounter.tc_quality = 1000; 636 max_freq >>= tsc_shift; 637 638 init: 639 for (shift = 0; shift <= 31 && (tsc_freq >> shift) > max_freq; shift++) 640 ; 641 642 /* 643 * Timecounter implementation selection, top to bottom: 644 * - If RDTSCP is available, use RDTSCP. 645 * - If fence instructions are provided (SSE2), use LFENCE;RDTSC 646 * on Intel, and MFENCE;RDTSC on AMD. 647 * - For really old CPUs, just use RDTSC. 648 */ 649 if ((amd_feature & AMDID_RDTSCP) != 0) { 650 tsc_timecounter.tc_get_timecount = shift > 0 ? 651 tscp_get_timecount_low : tscp_get_timecount; 652 } else if ((cpu_feature & CPUID_SSE2) != 0 && mp_ncpus > 1) { 653 if (cpu_vendor_id == CPU_VENDOR_AMD || 654 cpu_vendor_id == CPU_VENDOR_HYGON) { 655 tsc_timecounter.tc_get_timecount = shift > 0 ? 656 tsc_get_timecount_low_mfence : 657 tsc_get_timecount_mfence; 658 } else { 659 tsc_timecounter.tc_get_timecount = shift > 0 ? 660 tsc_get_timecount_low_lfence : 661 tsc_get_timecount_lfence; 662 } 663 } else { 664 tsc_timecounter.tc_get_timecount = shift > 0 ? 665 tsc_get_timecount_low : tsc_get_timecount; 666 } 667 if (shift > 0) { 668 tsc_timecounter.tc_name = "TSC-low"; 669 if (bootverbose) 670 printf("TSC timecounter discards lower %d bit(s)\n", 671 shift); 672 } 673 if (tsc_freq != 0) { 674 tsc_timecounter.tc_frequency = tsc_freq >> shift; 675 tsc_timecounter.tc_priv = (void *)(intptr_t)shift; 676 tc_init(&tsc_timecounter); 677 } 678 } 679 SYSINIT(tsc_tc, SI_SUB_SMP, SI_ORDER_ANY, init_TSC_tc, NULL); 680 681 void 682 resume_TSC(void) 683 { 684 #ifdef SMP 685 int quality; 686 687 /* If TSC was not good on boot, it is unlikely to become good now. */ 688 if (tsc_timecounter.tc_quality < 0) 689 return; 690 /* Nothing to do with UP. */ 691 if (mp_ncpus < 2) 692 return; 693 694 /* 695 * If TSC was good, a single synchronization should be enough, 696 * but honour smp_tsc_adjust if it's set. 697 */ 698 quality = test_tsc(MAX(smp_tsc_adjust, 1)); 699 if (quality != tsc_timecounter.tc_quality) { 700 printf("TSC timecounter quality changed: %d -> %d\n", 701 tsc_timecounter.tc_quality, quality); 702 tsc_timecounter.tc_quality = quality; 703 } 704 #endif /* SMP */ 705 } 706 707 /* 708 * When cpufreq levels change, find out about the (new) max frequency. We 709 * use this to update CPU accounting in case it got a lower estimate at boot. 710 */ 711 static void 712 tsc_levels_changed(void *arg, int unit) 713 { 714 device_t cf_dev; 715 struct cf_level *levels; 716 int count, error; 717 uint64_t max_freq; 718 719 /* Only use values from the first CPU, assuming all are equal. */ 720 if (unit != 0) 721 return; 722 723 /* Find the appropriate cpufreq device instance. */ 724 cf_dev = devclass_get_device(devclass_find("cpufreq"), unit); 725 if (cf_dev == NULL) { 726 printf("tsc_levels_changed() called but no cpufreq device?\n"); 727 return; 728 } 729 730 /* Get settings from the device and find the max frequency. */ 731 count = 64; 732 levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT); 733 if (levels == NULL) 734 return; 735 error = CPUFREQ_LEVELS(cf_dev, levels, &count); 736 if (error == 0 && count != 0) { 737 max_freq = (uint64_t)levels[0].total_set.freq * 1000000; 738 set_cputicker(rdtsc, max_freq, 1); 739 } else 740 printf("tsc_levels_changed: no max freq found\n"); 741 free(levels, M_TEMP); 742 } 743 744 /* 745 * If the TSC timecounter is in use, veto the pending change. It may be 746 * possible in the future to handle a dynamically-changing timecounter rate. 747 */ 748 static void 749 tsc_freq_changing(void *arg, const struct cf_level *level, int *status) 750 { 751 752 if (*status != 0 || timecounter != &tsc_timecounter) 753 return; 754 755 printf("timecounter TSC must not be in use when " 756 "changing frequencies; change denied\n"); 757 *status = EBUSY; 758 } 759 760 /* Update TSC freq with the value indicated by the caller. */ 761 static void 762 tsc_freq_changed(void *arg, const struct cf_level *level, int status) 763 { 764 uint64_t freq; 765 766 /* If there was an error during the transition, don't do anything. */ 767 if (tsc_disabled || status != 0) 768 return; 769 770 /* Total setting for this level gives the new frequency in MHz. */ 771 freq = (uint64_t)level->total_set.freq * 1000000; 772 atomic_store_rel_64(&tsc_freq, freq); 773 tsc_timecounter.tc_frequency = 774 freq >> (int)(intptr_t)tsc_timecounter.tc_priv; 775 } 776 777 static int 778 sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS) 779 { 780 int error; 781 uint64_t freq; 782 783 freq = atomic_load_acq_64(&tsc_freq); 784 if (freq == 0) 785 return (EOPNOTSUPP); 786 error = sysctl_handle_64(oidp, &freq, 0, req); 787 if (error == 0 && req->newptr != NULL) { 788 atomic_store_rel_64(&tsc_freq, freq); 789 atomic_store_rel_64(&tsc_timecounter.tc_frequency, 790 freq >> (int)(intptr_t)tsc_timecounter.tc_priv); 791 } 792 return (error); 793 } 794 795 SYSCTL_PROC(_machdep, OID_AUTO, tsc_freq, 796 CTLTYPE_U64 | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 797 0, 0, sysctl_machdep_tsc_freq, "QU", 798 "Time Stamp Counter frequency"); 799 800 static u_int 801 tsc_get_timecount(struct timecounter *tc __unused) 802 { 803 804 return (rdtsc32()); 805 } 806 807 static u_int 808 tscp_get_timecount(struct timecounter *tc __unused) 809 { 810 811 return (rdtscp32()); 812 } 813 814 static inline u_int 815 tsc_get_timecount_low(struct timecounter *tc) 816 { 817 uint32_t rv; 818 819 __asm __volatile("rdtsc; shrd %%cl, %%edx, %0" 820 : "=a" (rv) : "c" ((int)(intptr_t)tc->tc_priv) : "edx"); 821 return (rv); 822 } 823 824 static u_int 825 tscp_get_timecount_low(struct timecounter *tc) 826 { 827 uint32_t rv; 828 829 __asm __volatile("rdtscp; movl %1, %%ecx; shrd %%cl, %%edx, %0" 830 : "=&a" (rv) : "m" (tc->tc_priv) : "ecx", "edx"); 831 return (rv); 832 } 833 834 static u_int 835 tsc_get_timecount_lfence(struct timecounter *tc __unused) 836 { 837 838 lfence(); 839 return (rdtsc32()); 840 } 841 842 static u_int 843 tsc_get_timecount_low_lfence(struct timecounter *tc) 844 { 845 846 lfence(); 847 return (tsc_get_timecount_low(tc)); 848 } 849 850 static u_int 851 tsc_get_timecount_mfence(struct timecounter *tc __unused) 852 { 853 854 mfence(); 855 return (rdtsc32()); 856 } 857 858 static u_int 859 tsc_get_timecount_low_mfence(struct timecounter *tc) 860 { 861 862 mfence(); 863 return (tsc_get_timecount_low(tc)); 864 } 865 866 static uint32_t 867 x86_tsc_vdso_timehands(struct vdso_timehands *vdso_th, struct timecounter *tc) 868 { 869 870 vdso_th->th_algo = VDSO_TH_ALGO_X86_TSC; 871 vdso_th->th_x86_shift = (int)(intptr_t)tc->tc_priv; 872 vdso_th->th_x86_hpet_idx = 0xffffffff; 873 bzero(vdso_th->th_res, sizeof(vdso_th->th_res)); 874 return (1); 875 } 876 877 #ifdef COMPAT_FREEBSD32 878 static uint32_t 879 x86_tsc_vdso_timehands32(struct vdso_timehands32 *vdso_th32, 880 struct timecounter *tc) 881 { 882 883 vdso_th32->th_algo = VDSO_TH_ALGO_X86_TSC; 884 vdso_th32->th_x86_shift = (int)(intptr_t)tc->tc_priv; 885 vdso_th32->th_x86_hpet_idx = 0xffffffff; 886 bzero(vdso_th32->th_res, sizeof(vdso_th32->th_res)); 887 return (1); 888 } 889 #endif 890