/*- * Copyright (c) 1998-2003 Poul-Henning Kamp * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD: head/sys/x86/x86/tsc.c 221178 2011-04-28 17:56:02Z jkim $"); #include "opt_clock.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "cpufreq_if.h" uint64_t tsc_freq; int tsc_is_invariant; int tsc_perf_stat; static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag; SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN, &tsc_is_invariant, 0, "Indicates whether the TSC is P-state invariant"); TUNABLE_INT("kern.timecounter.invariant_tsc", &tsc_is_invariant); #ifdef SMP static int smp_tsc; SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0, "Indicates whether the TSC is safe to use in SMP mode"); TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc); #endif static int tsc_disabled; SYSCTL_INT(_machdep, OID_AUTO, disable_tsc, CTLFLAG_RDTUN, &tsc_disabled, 0, "Disable x86 Time Stamp Counter"); TUNABLE_INT("machdep.disable_tsc", &tsc_disabled); static int tsc_skip_calibration; SYSCTL_INT(_machdep, OID_AUTO, disable_tsc_calibration, CTLFLAG_RDTUN, &tsc_skip_calibration, 0, "Disable TSC frequency calibration"); TUNABLE_INT("machdep.disable_tsc_calibration", &tsc_skip_calibration); static void tsc_freq_changed(void *arg, const struct cf_level *level, int status); static void tsc_freq_changing(void *arg, const struct cf_level *level, int *status); static unsigned tsc_get_timecount(struct timecounter *tc); static void tsc_levels_changed(void *arg, int unit); static struct timecounter tsc_timecounter = { tsc_get_timecount, /* get_timecount */ 0, /* no poll_pps */ ~0u, /* counter_mask */ 0, /* frequency */ "TSC", /* name */ 800, /* quality (adjusted in code) */ }; static void tsc_freq_intel(void) { char brand[48]; u_int regs[4]; uint64_t freq; char *p; u_int i; /* * Intel Processor Identification and the CPUID Instruction * Application Note 485. * * http://www.intel.com/assets/pdf/appnote/241618.pdf */ if (cpu_exthigh >= 0x80000004) { p = brand; for (i = 0x80000002; i < 0x80000005; i++) { do_cpuid(i, regs); memcpy(p, regs, sizeof(regs)); p += sizeof(regs); } p = NULL; for (i = 0; i < sizeof(brand) - 1; i++) if (brand[i] == 'H' && brand[i + 1] == 'z') p = brand + i; if (p != NULL) { p -= 5; switch (p[4]) { case 'M': i = 1; break; case 'G': i = 1000; break; case 'T': i = 1000000; break; default: return; } #define C2D(c) ((c) - '0') if (p[1] == '.') { freq = C2D(p[0]) * 1000; freq += C2D(p[2]) * 100; freq += C2D(p[3]) * 10; freq *= i * 1000; } else { freq = C2D(p[0]) * 1000; freq += C2D(p[1]) * 100; freq += C2D(p[2]) * 10; freq += C2D(p[3]); freq *= i * 1000000; } #undef C2D tsc_freq = freq; } } } static void probe_tsc_freq(void) { u_int regs[4]; uint64_t tsc1, tsc2; switch (cpu_vendor_id) { case CPU_VENDOR_AMD: if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || (vm_guest == VM_GUEST_NO && CPUID_TO_FAMILY(cpu_id) >= 0x10)) tsc_is_invariant = 1; break; case CPU_VENDOR_INTEL: if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 || (vm_guest == VM_GUEST_NO && ((CPUID_TO_FAMILY(cpu_id) == 0x6 && CPUID_TO_MODEL(cpu_id) >= 0xe) || (CPUID_TO_FAMILY(cpu_id) == 0xf && CPUID_TO_MODEL(cpu_id) >= 0x3)))) tsc_is_invariant = 1; break; case CPU_VENDOR_CENTAUR: if (vm_guest == VM_GUEST_NO && CPUID_TO_FAMILY(cpu_id) == 0x6 && CPUID_TO_MODEL(cpu_id) >= 0xf && (rdmsr(0x1203) & 0x100000000ULL) == 0) tsc_is_invariant = 1; break; } if (cpu_high >= 6) { do_cpuid(6, regs); if ((regs[2] & CPUID_PERF_STAT) != 0) { /* * XXX Some emulators expose host CPUID without actual * support for these MSRs. We must test whether they * really work. */ wrmsr(MSR_MPERF, 0); wrmsr(MSR_APERF, 0); DELAY(10); if (rdmsr(MSR_MPERF) > 0 && rdmsr(MSR_APERF) > 0) tsc_perf_stat = 1; } } if (tsc_skip_calibration) { if (cpu_vendor_id == CPU_VENDOR_INTEL) tsc_freq_intel(); return; } if (bootverbose) printf("Calibrating TSC clock ... "); tsc1 = rdtsc(); DELAY(1000000); tsc2 = rdtsc(); tsc_freq = tsc2 - tsc1; if (bootverbose) printf("TSC clock: %ju Hz\n", (intmax_t)tsc_freq); } void init_TSC(void) { if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) return; probe_tsc_freq(); /* * Inform CPU accounting about our boot-time clock rate. This will * be updated if someone loads a cpufreq driver after boot that * discovers a new max frequency. */ if (tsc_freq != 0) set_cputicker(rdtsc, tsc_freq, !tsc_is_invariant); if (tsc_is_invariant) return; /* Register to find out about changes in CPU frequency. */ tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change, tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST); tsc_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change, tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST); tsc_levels_tag = EVENTHANDLER_REGISTER(cpufreq_levels_changed, tsc_levels_changed, NULL, EVENTHANDLER_PRI_ANY); } void init_TSC_tc(void) { if ((cpu_feature & CPUID_TSC) == 0 || tsc_disabled) return; /* * We can not use the TSC if we support APM. Precise timekeeping * on an APM'ed machine is at best a fools pursuit, since * any and all of the time spent in various SMM code can't * be reliably accounted for. Reading the RTC is your only * source of reliable time info. The i8254 loses too, of course, * but we need to have some kind of time... * We don't know at this point whether APM is going to be used * or not, nor when it might be activated. Play it safe. */ if (power_pm_get_type() == POWER_PM_TYPE_APM) { tsc_timecounter.tc_quality = -1000; if (bootverbose) printf("TSC timecounter disabled: APM enabled.\n"); } #ifdef SMP /* * We can not use the TSC in SMP mode unless the TSCs on all CPUs * are somehow synchronized. Some hardware configurations do * this, but we have no way of determining whether this is the * case, so we do not use the TSC in multi-processor systems * unless the user indicated (by setting kern.timecounter.smp_tsc * to 1) that he believes that his TSCs are synchronized. */ if (mp_ncpus > 1 && !smp_tsc) tsc_timecounter.tc_quality = -100; #endif if (tsc_freq != 0) { tsc_timecounter.tc_frequency = tsc_freq; tc_init(&tsc_timecounter); } } /* * When cpufreq levels change, find out about the (new) max frequency. We * use this to update CPU accounting in case it got a lower estimate at boot. */ static void tsc_levels_changed(void *arg, int unit) { device_t cf_dev; struct cf_level *levels; int count, error; uint64_t max_freq; /* Only use values from the first CPU, assuming all are equal. */ if (unit != 0) return; /* Find the appropriate cpufreq device instance. */ cf_dev = devclass_get_device(devclass_find("cpufreq"), unit); if (cf_dev == NULL) { printf("tsc_levels_changed() called but no cpufreq device?\n"); return; } /* Get settings from the device and find the max frequency. */ count = 64; levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT); if (levels == NULL) return; error = CPUFREQ_LEVELS(cf_dev, levels, &count); if (error == 0 && count != 0) { max_freq = (uint64_t)levels[0].total_set.freq * 1000000; set_cputicker(rdtsc, max_freq, 1); } else printf("tsc_levels_changed: no max freq found\n"); free(levels, M_TEMP); } /* * If the TSC timecounter is in use, veto the pending change. It may be * possible in the future to handle a dynamically-changing timecounter rate. */ static void tsc_freq_changing(void *arg, const struct cf_level *level, int *status) { if (*status != 0 || timecounter != &tsc_timecounter) return; printf("timecounter TSC must not be in use when " "changing frequencies; change denied\n"); *status = EBUSY; } /* Update TSC freq with the value indicated by the caller. */ static void tsc_freq_changed(void *arg, const struct cf_level *level, int status) { uint64_t freq; /* If there was an error during the transition, don't do anything. */ if (tsc_disabled || status != 0) return; /* Total setting for this level gives the new frequency in MHz. */ freq = (uint64_t)level->total_set.freq * 1000000; atomic_store_rel_64(&tsc_freq, freq); atomic_store_rel_64(&tsc_timecounter.tc_frequency, freq); } static int sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS) { int error; uint64_t freq; freq = atomic_load_acq_64(&tsc_freq); if (freq == 0) return (EOPNOTSUPP); error = sysctl_handle_64(oidp, &freq, 0, req); if (error == 0 && req->newptr != NULL) { atomic_store_rel_64(&tsc_freq, freq); atomic_store_rel_64(&tsc_timecounter.tc_frequency, freq); } return (error); } SYSCTL_PROC(_machdep, OID_AUTO, tsc_freq, CTLTYPE_U64 | CTLFLAG_RW, 0, 0, sysctl_machdep_tsc_freq, "QU", "Time Stamp Counter frequency"); static u_int tsc_get_timecount(struct timecounter *tc) { return (rdtsc32()); }