osfmk/i386/tsc.c

   1 /*
   2  * Copyright (c) 2005-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31
  32 /*
  33  *      File:           i386/tsc.c
  34  *      Purpose:        Initializes the TSC and the various conversion
  35  *                      factors needed by other parts of the system.
  36  */
  37
  38
  39 #include <mach/mach_types.h>
  40
  41 #include <kern/cpu_data.h>
  42 #include <kern/cpu_number.h>
  43 #include <kern/clock.h>
  44 #include <kern/host_notify.h>
  45 #include <kern/macro_help.h>
  46 #include <kern/misc_protos.h>
  47 #include <kern/spl.h>
  48 #include <kern/assert.h>
  49 #include <mach/vm_prot.h>
  50 #include <vm/pmap.h>
  51 #include <vm/vm_kern.h>         /* for kernel_map */
  52 #include <architecture/i386/pio.h>
  53 #include <i386/machine_cpu.h>
  54 #include <i386/cpuid.h>
  55 #include <i386/mp.h>
  56 #include <i386/machine_routines.h>
  57 #include <i386/proc_reg.h>
  58 #include <i386/tsc.h>
  59 #include <i386/misc_protos.h>
  60 #include <pexpert/pexpert.h>
  61 #include <machine/limits.h>
  62 #include <machine/commpage.h>
  63 #include <sys/kdebug.h>
  64 #include <pexpert/device_tree.h>
  65
  66 uint64_t        busFCvtt2n = 0;
  67 uint64_t        busFCvtn2t = 0;
  68 uint64_t        tscFreq = 0;
  69 uint64_t        tscFCvtt2n = 0;
  70 uint64_t        tscFCvtn2t = 0;
  71 uint64_t        tscGranularity = 0;
  72 uint64_t        bus2tsc = 0;
  73 uint64_t        busFreq = 0;
  74 uint32_t        flex_ratio = 0;
  75 uint32_t        flex_ratio_min = 0;
  76 uint32_t        flex_ratio_max = 0;
  77
  78 uint64_t        tsc_at_boot = 0;
  79
  80 #define bit(n)          (1ULL << (n))
  81 #define bitmask(h,l)    ((bit(h)|(bit(h)-1)) & ~(bit(l)-1))
  82 #define bitfield(x,h,l) (((x) & bitmask(h,l)) >> l)
  83
  84 /* Decimal powers: */
  85 #define kilo (1000ULL)
  86 #define Mega (kilo * kilo)
  87 #define Giga (kilo * Mega)
  88 #define Tera (kilo * Giga)
  89 #define Peta (kilo * Tera)
  90
  91 #define CPU_FAMILY_PENTIUM_M    (0x6)
  92
  93 /*
  94  * This routine extracts a frequency property in Hz from the device tree.
  95  * Also reads any initial TSC value at boot from the device tree.
  96  */
  97 static uint64_t
  98 EFI_get_frequency(const char *prop)
  99 {
 100         uint64_t        frequency = 0;
 101         DTEntry         entry;
 102         void            *value;
 103         unsigned int    size;
 104
 105         if (DTLookupEntry(0, "/efi/platform", &entry) != kSuccess) {
 106                 kprintf("EFI_get_frequency: didn't find /efi/platform\n");
 107                 return 0;
 108         }
 109         if (DTGetProperty(entry,prop,&value,&size) != kSuccess) {
 110                 kprintf("EFI_get_frequency: property %s not found\n", prop);
 111                 return 0;
 112         }
 113         if (size == sizeof(uint64_t)) {
 114                 frequency = *(uint64_t *) value;
 115                 kprintf("EFI_get_frequency: read %s value: %llu\n",
 116                         prop, frequency);
 117         }
 118
 119         /*
 120          * While we're here, see if EFI published an initial TSC value.
 121          */
 122         if (DTGetProperty(entry,"InitialTSC",&value,&size) == kSuccess) {
 123                 if (size == sizeof(uint64_t)) {
 124                         tsc_at_boot = *(uint64_t *) value;
 125                         kprintf("EFI_get_frequency: read InitialTSC: %llu\n",
 126                                 tsc_at_boot);
 127                 }
 128         }
 129
 130         return frequency;
 131 }
 132
 133 /*
 134  * Initialize the various conversion factors needed by code referencing
 135  * the TSC.
 136  */
 137 void
 138 tsc_init(void)
 139 {
 140         boolean_t       N_by_2_bus_ratio = FALSE;
 141
 142         if (cpuid_vmm_present()) {
 143                 kprintf("VMM vendor %u TSC frequency %u KHz bus frequency %u KHz\n",
 144                                 cpuid_vmm_info()->cpuid_vmm_family,
 145                                 cpuid_vmm_info()->cpuid_vmm_tsc_frequency,
 146                                 cpuid_vmm_info()->cpuid_vmm_bus_frequency);
 147
 148                 if (cpuid_vmm_info()->cpuid_vmm_tsc_frequency &&
 149                         cpuid_vmm_info()->cpuid_vmm_bus_frequency) {
 150
 151                         busFreq = (uint64_t)cpuid_vmm_info()->cpuid_vmm_bus_frequency * kilo;
 152                         busFCvtt2n = ((1 * Giga) << 32) / busFreq;
 153                         busFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / busFCvtt2n;
 154
 155                         tscFreq = (uint64_t)cpuid_vmm_info()->cpuid_vmm_tsc_frequency * kilo;
 156                         tscFCvtt2n = ((1 * Giga) << 32) / tscFreq;
 157                         tscFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / tscFCvtt2n;
 158
 159                         tscGranularity = tscFreq / busFreq;
 160
 161                         bus2tsc = tmrCvt(busFCvtt2n, tscFCvtn2t);
 162
 163                         return;
 164                 }
 165         }
 166
 167         switch (cpuid_cpufamily()) {
 168         case CPUFAMILY_INTEL_SKYLAKE: {
 169                 /*
 170                 * SkyLake and later has an Always Running Timer (ART) providing
 171                  * the reference frequency. CPUID leaf 0x15 determines the
 172                  * rationship between this and the TSC frequency expressed as
 173                  *   -  multiplier (numerator, N), and
 174                  *   -  divisor (denominator, M).
 175                  * So that TSC = ART * N / M.
 176                  */
 177                 cpuid_tsc_leaf_t *tsc_leafp = &cpuid_info()->cpuid_tsc_leaf;
 178                 uint64_t         N = (uint64_t) tsc_leafp->numerator;
 179                 uint64_t         M = (uint64_t) tsc_leafp->denominator;
 180                 uint64_t         refFreq;
 181
 182                 refFreq = EFI_get_frequency("ARTFrequency");
 183                 if (refFreq == 0)
 184                         refFreq = BASE_ART_CLOCK_SOURCE;
 185
 186                 assert(N != 0);
 187                 assert(M != 1);
 188                 tscFreq = refFreq * N / M;
 189                 busFreq = tscFreq;              /* bus is APIC frequency */
 190
 191                 kprintf(" ART: Frequency = %6d.%06dMHz, N/M = %lld/%llu\n",
 192                         (uint32_t)(refFreq / Mega),
 193                         (uint32_t)(refFreq % Mega),
 194                         N, M);
 195
 196                 break;
 197             }
 198         default: {
 199                 uint64_t msr_flex_ratio;
 200                 uint64_t msr_platform_info;
 201
 202                 /* See if FLEX_RATIO is being used */
 203                 msr_flex_ratio = rdmsr64(MSR_FLEX_RATIO);
 204                 msr_platform_info = rdmsr64(MSR_PLATFORM_INFO);
 205                 flex_ratio_min = (uint32_t)bitfield(msr_platform_info, 47, 40);
 206                 flex_ratio_max = (uint32_t)bitfield(msr_platform_info, 15, 8);
 207                 /* No BIOS-programed flex ratio. Use hardware max as default */
 208                 tscGranularity = flex_ratio_max;
 209                 if (msr_flex_ratio & bit(16)) {
 210                         /* Flex Enabled: Use this MSR if less than max */
 211                         flex_ratio = (uint32_t)bitfield(msr_flex_ratio, 15, 8);
 212                         if (flex_ratio < flex_ratio_max)
 213                                 tscGranularity = flex_ratio;
 214                 }
 215
 216                 busFreq = EFI_get_frequency("FSBFrequency");
 217                 /* If EFI isn't configured correctly, use a constant
 218                  * value. See 6036811.
 219                  */
 220                 if (busFreq == 0)
 221                     busFreq = BASE_NHM_CLOCK_SOURCE;
 222
 223                 break;
 224             }
 225         case CPUFAMILY_INTEL_PENRYN: {
 226                 uint64_t        prfsts;
 227
 228                 prfsts = rdmsr64(IA32_PERF_STS);
 229                 tscGranularity = (uint32_t)bitfield(prfsts, 44, 40);
 230                 N_by_2_bus_ratio = (prfsts & bit(46)) != 0;
 231
 232                 busFreq = EFI_get_frequency("FSBFrequency");
 233             }
 234         }
 235
 236         if (busFreq != 0) {
 237                 busFCvtt2n = ((1 * Giga) << 32) / busFreq;
 238                 busFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / busFCvtt2n;
 239         } else {
 240                 panic("tsc_init: EFI not supported!\n");
 241         }
 242
 243         kprintf(" BUS: Frequency = %6d.%06dMHz, "
 244                 "cvtt2n = %08X.%08X, cvtn2t = %08X.%08X\n",
 245                 (uint32_t)(busFreq / Mega),
 246                 (uint32_t)(busFreq % Mega),
 247                 (uint32_t)(busFCvtt2n >> 32), (uint32_t)busFCvtt2n,
 248                 (uint32_t)(busFCvtn2t >> 32), (uint32_t)busFCvtn2t);
 249
 250         if (tscFreq == busFreq) {
 251                 bus2tsc = 1;
 252                 tscGranularity = 1;
 253                 tscFCvtn2t = busFCvtn2t;
 254                 tscFCvtt2n = busFCvtt2n;
 255         } else {
 256                 /*
 257                  * Get the TSC increment.  The TSC is incremented by this
 258                  * on every bus tick.  Calculate the TSC conversion factors
 259                  * to and from nano-seconds.
 260                  * The tsc granularity is also called the "bus ratio".
 261                  * If the N/2 bit is set this indicates the bus ration is
 262                  * 0.5 more than this - i.e.  that the true bus ratio
 263                  * is (2*tscGranularity + 1)/2.
 264                  */
 265                 if (N_by_2_bus_ratio)
 266                         tscFCvtt2n = busFCvtt2n * 2 / (1 + 2*tscGranularity);
 267                 else
 268                         tscFCvtt2n = busFCvtt2n / tscGranularity;
 269
 270                 tscFreq = ((1 * Giga)  << 32) / tscFCvtt2n;
 271                 tscFCvtn2t = 0xFFFFFFFFFFFFFFFFULL / tscFCvtt2n;
 272
 273                 /*
 274                  * Calculate conversion from BUS to TSC
 275                  */
 276                 bus2tsc = tmrCvt(busFCvtt2n, tscFCvtn2t);
 277         }
 278
 279         kprintf(" TSC: Frequency = %6d.%06dMHz, "
 280                 "cvtt2n = %08X.%08X, cvtn2t = %08X.%08X, gran = %lld%s\n",
 281                 (uint32_t)(tscFreq / Mega),
 282                 (uint32_t)(tscFreq % Mega),
 283                 (uint32_t)(tscFCvtt2n >> 32), (uint32_t)tscFCvtt2n,
 284                 (uint32_t)(tscFCvtn2t >> 32), (uint32_t)tscFCvtn2t,
 285                 tscGranularity, N_by_2_bus_ratio ? " (N/2)" : "");
 286 }
 287
 288 void
 289 tsc_get_info(tscInfo_t *info)
 290 {
 291         info->busFCvtt2n     = busFCvtt2n;
 292         info->busFCvtn2t     = busFCvtn2t;
 293         info->tscFreq        = tscFreq;
 294         info->tscFCvtt2n     = tscFCvtt2n;
 295         info->tscFCvtn2t     = tscFCvtn2t;
 296         info->tscGranularity = tscGranularity;
 297         info->bus2tsc        = bus2tsc;
 298         info->busFreq        = busFreq;
 299         info->flex_ratio     = flex_ratio;
 300         info->flex_ratio_min = flex_ratio_min;
 301         info->flex_ratio_max = flex_ratio_max;
 302 }