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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("$FreeBSD$"); 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 #include <dev/acpica/acpi_hpet.h> 52 53 #include "cpufreq_if.h" 54 55 uint64_t tsc_freq; 56 int tsc_is_invariant; 57 int tsc_perf_stat; 58 59 static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag; 60 61 SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN, 62 &tsc_is_invariant, 0, "Indicates whether the TSC is P-state 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 69 int smp_tsc_adjust = 0; 70 SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc_adjust, CTLFLAG_RDTUN, 71 &smp_tsc_adjust, 0, "Try to adjust TSC on APs to match BSP"); 72 #endif 73 74 static int tsc_shift = 1; 75 SYSCTL_INT(_kern_timecounter, OID_AUTO, tsc_shift, CTLFLAG_RDTUN, 76 &tsc_shift, 0, "Shift to pre-apply for the maximum TSC frequency"); 77 78 static int tsc_disabled; 79 SYSCTL_INT(_machdep, OID_AUTO, disable_tsc, CTLFLAG_RDTUN, &tsc_disabled, 0, 80 "Disable x86 Time Stamp Counter"); 81 82 static int tsc_skip_calibration; 83 SYSCTL_INT(_machdep, OID_AUTO, disable_tsc_calibration, CTLFLAG_RDTUN, 84 &tsc_skip_calibration, 0, "Disable TSC frequency calibration"); 85 86 static void tsc_freq_changed(void *arg, const struct cf_level *level, 87 int status); 88 static void tsc_freq_changing(void *arg, const struct cf_level *level, 89 int *status); 90 static unsigned tsc_get_timecount(struct timecounter *tc); 91 static inline unsigned tsc_get_timecount_low(struct timecounter *tc); 92 static unsigned tsc_get_timecount_lfence(struct timecounter *tc); 93 static unsigned tsc_get_timecount_low_lfence(struct timecounter *tc); 94 static unsigned tsc_get_timecount_mfence(struct timecounter *tc); 95 static unsigned tsc_get_timecount_low_mfence(struct timecounter *tc); 96 static void tsc_levels_changed(void *arg, int unit); 97 static uint32_t x86_tsc_vdso_timehands(struct vdso_timehands *vdso_th, 98 struct timecounter *tc); 99 #ifdef COMPAT_FREEBSD32 100 static uint32_t x86_tsc_vdso_timehands32(struct vdso_timehands32 *vdso_th32, 101 struct timecounter *tc); 102 #endif 103 104 static struct timecounter tsc_timecounter = { 105 .tc_get_timecount = tsc_get_timecount, 106 .tc_counter_mask = ~0u, 107 .tc_name = "TSC", 108 .tc_quality = 800, /* adjusted in code */ 109 .tc_fill_vdso_timehands = x86_tsc_vdso_timehands, 110 #ifdef COMPAT_FREEBSD32 111 .tc_fill_vdso_timehands32 = x86_tsc_vdso_timehands32, 112 #endif 113 }; 114 115 static void 116 tsc_freq_vmware(void) 117 { 118 u_int regs[4]; 119 120 if (hv_high >= 0x40000010) { 121 do_cpuid(0x40000010, regs); 122 tsc_freq = regs[0] * 1000; 123 } else { 124 vmware_hvcall(VMW_HVCMD_GETHZ, regs); 125 if (regs[1] != UINT_MAX) 126 tsc_freq = regs[0] | ((uint64_t)regs[1] << 32); 127 } 128 tsc_is_invariant = 1; 129 } 130 131 /* 132 * Calculate TSC frequency using information from the CPUID leaf 0x15 133 * 'Time Stamp Counter and Nominal Core Crystal Clock'. If leaf 0x15 134 * is not functional, as it is on Skylake/Kabylake, try 0x16 'Processor 135 * Frequency Information'. Leaf 0x16 is described in the SDM as 136 * informational only, but if 0x15 did not work, and TSC calibration 137 * is disabled, it is the best we can get at all. It should still be 138 * an improvement over the parsing of the CPU model name in 139 * tsc_freq_intel(), when available. 140 */ 141 static bool 142 tsc_freq_cpuid(void) 143 { 144 u_int regs[4]; 145 146 if (cpu_high < 0x15) 147 return (false); 148 do_cpuid(0x15, regs); 149 if (regs[0] != 0 && regs[1] != 0 && regs[2] != 0) { 150 tsc_freq = (uint64_t)regs[2] * regs[1] / regs[0]; 151 return (true); 152 } 153 154 if (cpu_high < 0x16) 155 return (false); 156 do_cpuid(0x16, regs); 157 if (regs[0] != 0) { 158 tsc_freq = (uint64_t)regs[0] * 1000000; 159 return (true); 160 } 161 162 return (false); 163 } 164 165 static void 166 tsc_freq_intel(void) 167 { 168 char brand[48]; 169 u_int regs[4]; 170 uint64_t freq; 171 char *p; 172 u_int i; 173 174 /* 175 * Intel Processor Identification and the CPUID Instruction 176 * Application Note 485. 177 * http://www.intel.com/assets/pdf/appnote/241618.pdf 178 */ 179 if (cpu_exthigh >= 0x80000004) { 180 p = brand; 181 for (i = 0x80000002; i < 0x80000005; i++) { 182 do_cpuid(i, regs); 183 memcpy(p, regs, sizeof(regs)); 184 p += sizeof(regs); 185 } 186 p = NULL; 187 for (i = 0; i < sizeof(brand) - 1; i++) 188 if (brand[i] == 'H' && brand[i + 1] == 'z') 189 p = brand + i; 190 if (p != NULL) { 191 p -= 5; 192 switch (p[4]) { 193 case 'M': 194 i = 1; 195 break; 196 case 'G': 197 i = 1000; 198 break; 199 case 'T': 200 i = 1000000; 201 break; 202 default: 203 return; 204 } 205 #define C2D(c) ((c) - '') 206 if (p[1] == '.') { 207 freq = C2D(p[0]) * 1000; 208 freq += C2D(p[2]) * 100; 209 freq += C2D(p[3]) * 10; 210 freq *= i * 1000; 211 } else { 212 freq = C2D(p[0]) * 1000; 213 freq += C2D(p[1]) * 100; 214 freq += C2D(p[2]) * 10; 215 freq += C2D(p[3]); 216 freq *= i * 1000000; 217 } 218 #undef C2D 219 tsc_freq = freq; 220 } 221 } 222 } 223 224 static void 225 probe_tsc_freq(void) 226 { 227 u_int regs[4]; 228 uint64_t tsc1, tsc2; 229 230 if (cpu_high >= 6) { 231 do_cpuid(6, regs); 232 if ((regs[2] & CPUID_PERF_STAT) != 0) { 233 /* 234 * XXX Some emulators expose host CPUID without actual 235 * support for these MSRs. We must test whether they 236 * really work. 237 */ 238 wrmsr(MSR_MPERF, 0); 239 wrmsr(MSR_APERF, 0); 240 DELAY(10); 241 if (rdmsr(MSR_MPERF) > 0 && rdmsr(MSR_APERF) > 0) 242 tsc_perf_stat = 1; 243 } 244 } 245 246 if (vm_guest == VM_GUEST_VMWARE) { 247 tsc_freq_vmware(); 248 return; 249 } 250 251 switch (cpu_vendor_id) { 252 case CPU_VENDOR_AMD: 253 if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || 254 (vm_guest == VM_GUEST_NO && 255 CPUID_TO_FAMILY(cpu_id) >= 0x10)) 256 tsc_is_invariant = 1; 257 if (cpu_feature & CPUID_SSE2) { 258 tsc_timecounter.tc_get_timecount = 259 tsc_get_timecount_mfence; 260 } 261 break; 262 case CPU_VENDOR_INTEL: 263 if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || 264 (vm_guest == VM_GUEST_NO && 265 ((CPUID_TO_FAMILY(cpu_id) == 0x6 && 266 CPUID_TO_MODEL(cpu_id) >= 0xe) || 267 (CPUID_TO_FAMILY(cpu_id) == 0xf && 268 CPUID_TO_MODEL(cpu_id) >= 0x3)))) 269 tsc_is_invariant = 1; 270 if (cpu_feature & CPUID_SSE2) { 271 tsc_timecounter.tc_get_timecount = 272 tsc_get_timecount_lfence; 273 } 274 break; 275 case CPU_VENDOR_CENTAUR: 276 if (vm_guest == VM_GUEST_NO && 277 CPUID_TO_FAMILY(cpu_id) == 0x6 && 278 CPUID_TO_MODEL(cpu_id) >= 0xf && 279 (rdmsr(0x1203) & 0x100000000ULL) == 0) 280 tsc_is_invariant = 1; 281 if (cpu_feature & CPUID_SSE2) { 282 tsc_timecounter.tc_get_timecount = 283 tsc_get_timecount_lfence; 284 } 285 break; 286 } 287 288 if (tsc_skip_calibration) { 289 if (tsc_freq_cpuid()) 290 ; 291 else if (cpu_vendor_id == CPU_VENDOR_INTEL) 292 tsc_freq_intel(); 293 } else { 294 if (bootverbose) 295 printf("Calibrating TSC clock ... "); 296 tsc1 = rdtsc(); 297 DELAY(1000000); 298 tsc2 = rdtsc(); 299 tsc_freq = tsc2 - tsc1; 300 } 301 if (bootverbose) 302 printf("TSC clock: %ju Hz\n", (intmax_t)tsc_freq); 303 } 304 305 void 306 init_TSC(void) 307 { 308 309 if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) 310 return; 311 312 #ifdef __i386__ 313 /* The TSC is known to be broken on certain CPUs. */ 314 switch (cpu_vendor_id) { 315 case CPU_VENDOR_AMD: 316 switch (cpu_id & 0xFF0) { 317 case 0x500: 318 /* K5 Model 0 */ 319 return; 320 } 321 break; 322 case CPU_VENDOR_CENTAUR: 323 switch (cpu_id & 0xff0) { 324 case 0x540: 325 /* 326 * http://www.centtech.com/c6_data_sheet.pdf 327 * 328 * I-12 RDTSC may return incoherent values in EDX:EAX 329 * I-13 RDTSC hangs when certain event counters are used 330 */ 331 return; 332 } 333 break; 334 case CPU_VENDOR_NSC: 335 switch (cpu_id & 0xff0) { 336 case 0x540: 337 if ((cpu_id & CPUID_STEPPING) == 0) 338 return; 339 break; 340 } 341 break; 342 } 343 #endif 344 345 probe_tsc_freq(); 346 347 /* 348 * Inform CPU accounting about our boot-time clock rate. This will 349 * be updated if someone loads a cpufreq driver after boot that 350 * discovers a new max frequency. 351 */ 352 if (tsc_freq != 0) 353 set_cputicker(rdtsc, tsc_freq, !tsc_is_invariant); 354 355 if (tsc_is_invariant) 356 return; 357 358 /* Register to find out about changes in CPU frequency. */ 359 tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change, 360 tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST); 361 tsc_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change, 362 tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST); 363 tsc_levels_tag = EVENTHANDLER_REGISTER(cpufreq_levels_changed, 364 tsc_levels_changed, NULL, EVENTHANDLER_PRI_ANY); 365 } 366 367 #ifdef SMP 368 369 /* 370 * RDTSC is not a serializing instruction, and does not drain 371 * instruction stream, so we need to drain the stream before executing 372 * it. It could be fixed by use of RDTSCP, except the instruction is 373 * not available everywhere. 374 * 375 * Use CPUID for draining in the boot-time SMP constistency test. The 376 * timecounters use MFENCE for AMD CPUs, and LFENCE for others (Intel 377 * and VIA) when SSE2 is present, and nothing on older machines which 378 * also do not issue RDTSC prematurely. There, testing for SSE2 and 379 * vendor is too cumbersome, and we learn about TSC presence from CPUID. 380 * 381 * Do not use do_cpuid(), since we do not need CPUID results, which 382 * have to be written into memory with do_cpuid(). 383 */ 384 #define TSC_READ(x) \ 385 static void \ 386 tsc_read_##x(void *arg) \ 387 { \ 388 uint64_t *tsc = arg; \ 389 u_int cpu = PCPU_GET(cpuid); \ 390 \ 391 __asm __volatile("cpuid" : : : "eax", "ebx", "ecx", "edx"); \ 392 tsc[cpu * 3 + x] = rdtsc(); \ 393 } 394 TSC_READ(0) 395 TSC_READ(1) 396 TSC_READ(2) 397 #undef TSC_READ 398 399 #define N 1000 400 401 static void 402 comp_smp_tsc(void *arg) 403 { 404 uint64_t *tsc; 405 int64_t d1, d2; 406 u_int cpu = PCPU_GET(cpuid); 407 u_int i, j, size; 408 409 size = (mp_maxid + 1) * 3; 410 for (i = 0, tsc = arg; i < N; i++, tsc += size) 411 CPU_FOREACH(j) { 412 if (j == cpu) 413 continue; 414 d1 = tsc[cpu * 3 + 1] - tsc[j * 3]; 415 d2 = tsc[cpu * 3 + 2] - tsc[j * 3 + 1]; 416 if (d1 <= 0 || d2 <= 0) { 417 smp_tsc = 0; 418 return; 419 } 420 } 421 } 422 423 static void 424 adj_smp_tsc(void *arg) 425 { 426 uint64_t *tsc; 427 int64_t d, min, max; 428 u_int cpu = PCPU_GET(cpuid); 429 u_int first, i, size; 430 431 first = CPU_FIRST(); 432 if (cpu == first) 433 return; 434 min = INT64_MIN; 435 max = INT64_MAX; 436 size = (mp_maxid + 1) * 3; 437 for (i = 0, tsc = arg; i < N; i++, tsc += size) { 438 d = tsc[first * 3] - tsc[cpu * 3 + 1]; 439 if (d > min) 440 min = d; 441 d = tsc[first * 3 + 1] - tsc[cpu * 3 + 2]; 442 if (d > min) 443 min = d; 444 d = tsc[first * 3 + 1] - tsc[cpu * 3]; 445 if (d < max) 446 max = d; 447 d = tsc[first * 3 + 2] - tsc[cpu * 3 + 1]; 448 if (d < max) 449 max = d; 450 } 451 if (min > max) 452 return; 453 d = min / 2 + max / 2; 454 __asm __volatile ( 455 "movl $0x10, %%ecx\n\t" 456 "rdmsr\n\t" 457 "addl %%edi, %%eax\n\t" 458 "adcl %%esi, %%edx\n\t" 459 "wrmsr\n" 460 : /* No output */ 461 : "D" ((uint32_t)d), "S" ((uint32_t)(d >> 32)) 462 : "ax", "cx", "dx", "cc" 463 ); 464 } 465 466 static int 467 test_tsc(int adj_max_count) 468 { 469 uint64_t *data, *tsc; 470 u_int i, size, adj; 471 472 if ((!smp_tsc && !tsc_is_invariant) || vm_guest) 473 return (-100); 474 size = (mp_maxid + 1) * 3; 475 data = malloc(sizeof(*data) * size * N, M_TEMP, M_WAITOK); 476 adj = 0; 477 retry: 478 for (i = 0, tsc = data; i < N; i++, tsc += size) 479 smp_rendezvous(tsc_read_0, tsc_read_1, tsc_read_2, tsc); 480 smp_tsc = 1; /* XXX */ 481 smp_rendezvous(smp_no_rendezvous_barrier, comp_smp_tsc, 482 smp_no_rendezvous_barrier, data); 483 if (!smp_tsc && adj < adj_max_count) { 484 adj++; 485 smp_rendezvous(smp_no_rendezvous_barrier, adj_smp_tsc, 486 smp_no_rendezvous_barrier, data); 487 goto retry; 488 } 489 free(data, M_TEMP); 490 if (bootverbose) 491 printf("SMP: %sed TSC synchronization test%s\n", 492 smp_tsc ? "pass" : "fail", 493 adj > 0 ? " after adjustment" : ""); 494 if (smp_tsc && tsc_is_invariant) { 495 switch (cpu_vendor_id) { 496 case CPU_VENDOR_AMD: 497 /* 498 * Processor Programming Reference (PPR) for AMD 499 * Family 17h states that the TSC uses a common 500 * reference for all sockets, cores and threads. 501 */ 502 if (CPUID_TO_FAMILY(cpu_id) >= 0x17) 503 return (1000); 504 /* 505 * Starting with Family 15h processors, TSC clock 506 * source is in the north bridge. Check whether 507 * we have a single-socket/multi-core platform. 508 * XXX Need more work for complex cases. 509 */ 510 if (CPUID_TO_FAMILY(cpu_id) < 0x15 || 511 (amd_feature2 & AMDID2_CMP) == 0 || 512 smp_cpus > (cpu_procinfo2 & AMDID_CMP_CORES) + 1) 513 break; 514 return (1000); 515 case CPU_VENDOR_INTEL: 516 /* 517 * XXX Assume Intel platforms have synchronized TSCs. 518 */ 519 return (1000); 520 } 521 return (800); 522 } 523 return (-100); 524 } 525 526 #undef N 527 528 #endif /* SMP */ 529 530 static void 531 init_TSC_tc(void) 532 { 533 uint64_t max_freq; 534 int shift; 535 536 if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) 537 return; 538 539 /* 540 * Limit timecounter frequency to fit in an int and prevent it from 541 * overflowing too fast. 542 */ 543 max_freq = UINT_MAX; 544 545 /* 546 * We can not use the TSC if we support APM. Precise timekeeping 547 * on an APM'ed machine is at best a fools pursuit, since 548 * any and all of the time spent in various SMM code can't 549 * be reliably accounted for. Reading the RTC is your only 550 * source of reliable time info. The i8254 loses too, of course, 551 * but we need to have some kind of time... 552 * We don't know at this point whether APM is going to be used 553 * or not, nor when it might be activated. Play it safe. 554 */ 555 if (power_pm_get_type() == POWER_PM_TYPE_APM) { 556 tsc_timecounter.tc_quality = -1000; 557 if (bootverbose) 558 printf("TSC timecounter disabled: APM enabled.\n"); 559 goto init; 560 } 561 562 /* 563 * Intel CPUs without a C-state invariant TSC can stop the TSC 564 * in either C2 or C3. Disable use of C2 and C3 while using 565 * the TSC as the timecounter. The timecounter can be changed 566 * to enable C2 and C3. 567 * 568 * Note that the TSC is used as the cputicker for computing 569 * thread runtime regardless of the timecounter setting, so 570 * using an alternate timecounter and enabling C2 or C3 can 571 * result incorrect runtimes for kernel idle threads (but not 572 * for any non-idle threads). 573 */ 574 if (cpu_vendor_id == CPU_VENDOR_INTEL && 575 (amd_pminfo & AMDPM_TSC_INVARIANT) == 0) { 576 tsc_timecounter.tc_flags |= TC_FLAGS_C2STOP; 577 if (bootverbose) 578 printf("TSC timecounter disables C2 and C3.\n"); 579 } 580 581 /* 582 * We can not use the TSC in SMP mode unless the TSCs on all CPUs 583 * are synchronized. If the user is sure that the system has 584 * synchronized TSCs, set kern.timecounter.smp_tsc tunable to a 585 * non-zero value. The TSC seems unreliable in virtualized SMP 586 * environments, so it is set to a negative quality in those cases. 587 */ 588 #ifdef SMP 589 if (mp_ncpus > 1) 590 tsc_timecounter.tc_quality = test_tsc(smp_tsc_adjust); 591 else 592 #endif /* SMP */ 593 if (tsc_is_invariant) 594 tsc_timecounter.tc_quality = 1000; 595 max_freq >>= tsc_shift; 596 597 init: 598 for (shift = 0; shift <= 31 && (tsc_freq >> shift) > max_freq; shift++) 599 ; 600 if ((cpu_feature & CPUID_SSE2) != 0 && mp_ncpus > 1) { 601 if (cpu_vendor_id == CPU_VENDOR_AMD) { 602 tsc_timecounter.tc_get_timecount = shift > 0 ? 603 tsc_get_timecount_low_mfence : 604 tsc_get_timecount_mfence; 605 } else { 606 tsc_timecounter.tc_get_timecount = shift > 0 ? 607 tsc_get_timecount_low_lfence : 608 tsc_get_timecount_lfence; 609 } 610 } else { 611 tsc_timecounter.tc_get_timecount = shift > 0 ? 612 tsc_get_timecount_low : tsc_get_timecount; 613 } 614 if (shift > 0) { 615 tsc_timecounter.tc_name = "TSC-low"; 616 if (bootverbose) 617 printf("TSC timecounter discards lower %d bit(s)\n", 618 shift); 619 } 620 if (tsc_freq != 0) { 621 tsc_timecounter.tc_frequency = tsc_freq >> shift; 622 tsc_timecounter.tc_priv = (void *)(intptr_t)shift; 623 tc_init(&tsc_timecounter); 624 } 625 } 626 SYSINIT(tsc_tc, SI_SUB_SMP, SI_ORDER_ANY, init_TSC_tc, NULL); 627 628 void 629 resume_TSC(void) 630 { 631 #ifdef SMP 632 int quality; 633 634 /* If TSC was not good on boot, it is unlikely to become good now. */ 635 if (tsc_timecounter.tc_quality < 0) 636 return; 637 /* Nothing to do with UP. */ 638 if (mp_ncpus < 2) 639 return; 640 641 /* 642 * If TSC was good, a single synchronization should be enough, 643 * but honour smp_tsc_adjust if it's set. 644 */ 645 quality = test_tsc(MAX(smp_tsc_adjust, 1)); 646 if (quality != tsc_timecounter.tc_quality) { 647 printf("TSC timecounter quality changed: %d -> %d\n", 648 tsc_timecounter.tc_quality, quality); 649 tsc_timecounter.tc_quality = quality; 650 } 651 #endif /* SMP */ 652 } 653 654 /* 655 * When cpufreq levels change, find out about the (new) max frequency. We 656 * use this to update CPU accounting in case it got a lower estimate at boot. 657 */ 658 static void 659 tsc_levels_changed(void *arg, int unit) 660 { 661 device_t cf_dev; 662 struct cf_level *levels; 663 int count, error; 664 uint64_t max_freq; 665 666 /* Only use values from the first CPU, assuming all are equal. */ 667 if (unit != 0) 668 return; 669 670 /* Find the appropriate cpufreq device instance. */ 671 cf_dev = devclass_get_device(devclass_find("cpufreq"), unit); 672 if (cf_dev == NULL) { 673 printf("tsc_levels_changed() called but no cpufreq device?\n"); 674 return; 675 } 676 677 /* Get settings from the device and find the max frequency. */ 678 count = 64; 679 levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT); 680 if (levels == NULL) 681 return; 682 error = CPUFREQ_LEVELS(cf_dev, levels, &count); 683 if (error == 0 && count != 0) { 684 max_freq = (uint64_t)levels[0].total_set.freq * 1000000; 685 set_cputicker(rdtsc, max_freq, 1); 686 } else 687 printf("tsc_levels_changed: no max freq found\n"); 688 free(levels, M_TEMP); 689 } 690 691 /* 692 * If the TSC timecounter is in use, veto the pending change. It may be 693 * possible in the future to handle a dynamically-changing timecounter rate. 694 */ 695 static void 696 tsc_freq_changing(void *arg, const struct cf_level *level, int *status) 697 { 698 699 if (*status != 0 || timecounter != &tsc_timecounter) 700 return; 701 702 printf("timecounter TSC must not be in use when " 703 "changing frequencies; change denied\n"); 704 *status = EBUSY; 705 } 706 707 /* Update TSC freq with the value indicated by the caller. */ 708 static void 709 tsc_freq_changed(void *arg, const struct cf_level *level, int status) 710 { 711 uint64_t freq; 712 713 /* If there was an error during the transition, don't do anything. */ 714 if (tsc_disabled || status != 0) 715 return; 716 717 /* Total setting for this level gives the new frequency in MHz. */ 718 freq = (uint64_t)level->total_set.freq * 1000000; 719 atomic_store_rel_64(&tsc_freq, freq); 720 tsc_timecounter.tc_frequency = 721 freq >> (int)(intptr_t)tsc_timecounter.tc_priv; 722 } 723 724 static int 725 sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS) 726 { 727 int error; 728 uint64_t freq; 729 730 freq = atomic_load_acq_64(&tsc_freq); 731 if (freq == 0) 732 return (EOPNOTSUPP); 733 error = sysctl_handle_64(oidp, &freq, 0, req); 734 if (error == 0 && req->newptr != NULL) { 735 atomic_store_rel_64(&tsc_freq, freq); 736 atomic_store_rel_64(&tsc_timecounter.tc_frequency, 737 freq >> (int)(intptr_t)tsc_timecounter.tc_priv); 738 } 739 return (error); 740 } 741 742 SYSCTL_PROC(_machdep, OID_AUTO, tsc_freq, CTLTYPE_U64 | CTLFLAG_RW, 743 0, 0, sysctl_machdep_tsc_freq, "QU", "Time Stamp Counter frequency"); 744 745 static u_int 746 tsc_get_timecount(struct timecounter *tc __unused) 747 { 748 749 return (rdtsc32()); 750 } 751 752 static inline u_int 753 tsc_get_timecount_low(struct timecounter *tc) 754 { 755 uint32_t rv; 756 757 __asm __volatile("rdtsc; shrd %%cl, %%edx, %0" 758 : "=a" (rv) : "c" ((int)(intptr_t)tc->tc_priv) : "edx"); 759 return (rv); 760 } 761 762 static u_int 763 tsc_get_timecount_lfence(struct timecounter *tc __unused) 764 { 765 766 lfence(); 767 return (rdtsc32()); 768 } 769 770 static u_int 771 tsc_get_timecount_low_lfence(struct timecounter *tc) 772 { 773 774 lfence(); 775 return (tsc_get_timecount_low(tc)); 776 } 777 778 static u_int 779 tsc_get_timecount_mfence(struct timecounter *tc __unused) 780 { 781 782 mfence(); 783 return (rdtsc32()); 784 } 785 786 static u_int 787 tsc_get_timecount_low_mfence(struct timecounter *tc) 788 { 789 790 mfence(); 791 return (tsc_get_timecount_low(tc)); 792 } 793 794 static uint32_t 795 x86_tsc_vdso_timehands(struct vdso_timehands *vdso_th, struct timecounter *tc) 796 { 797 798 vdso_th->th_algo = VDSO_TH_ALGO_X86_TSC; 799 vdso_th->th_x86_shift = (int)(intptr_t)tc->tc_priv; 800 vdso_th->th_x86_hpet_idx = 0xffffffff; 801 bzero(vdso_th->th_res, sizeof(vdso_th->th_res)); 802 return (1); 803 } 804 805 #ifdef COMPAT_FREEBSD32 806 static uint32_t 807 x86_tsc_vdso_timehands32(struct vdso_timehands32 *vdso_th32, 808 struct timecounter *tc) 809 { 810 811 vdso_th32->th_algo = VDSO_TH_ALGO_X86_TSC; 812 vdso_th32->th_x86_shift = (int)(intptr_t)tc->tc_priv; 813 vdso_th32->th_x86_hpet_idx = 0xffffffff; 814 bzero(vdso_th32->th_res, sizeof(vdso_th32->th_res)); 815 return (1); 816 } 817 #endif
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