arch/x86/events/msr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/perf_event.h>
   3 #include <linux/nospec.h>
   4 #include <asm/intel-family.h>
   5
   6 enum perf_msr_id {
   7         PERF_MSR_TSC                    = 0,
   8         PERF_MSR_APERF                  = 1,
   9         PERF_MSR_MPERF                  = 2,
  10         PERF_MSR_PPERF                  = 3,
  11         PERF_MSR_SMI                    = 4,
  12         PERF_MSR_PTSC                   = 5,
  13         PERF_MSR_IRPERF                 = 6,
  14         PERF_MSR_THERM                  = 7,
  15         PERF_MSR_THERM_SNAP             = 8,
  16         PERF_MSR_THERM_UNIT             = 9,
  17         PERF_MSR_EVENT_MAX,
  18 };
  19
  20 static bool test_aperfmperf(int idx)
  21 {
  22         return boot_cpu_has(X86_FEATURE_APERFMPERF);
  23 }
  24
  25 static bool test_ptsc(int idx)
  26 {
  27         return boot_cpu_has(X86_FEATURE_PTSC);
  28 }
  29
  30 static bool test_irperf(int idx)
  31 {
  32         return boot_cpu_has(X86_FEATURE_IRPERF);
  33 }
  34
  35 static bool test_therm_status(int idx)
  36 {
  37         return boot_cpu_has(X86_FEATURE_DTHERM);
  38 }
  39
  40 static bool test_intel(int idx)
  41 {
  42         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
  43             boot_cpu_data.x86 != 6)
  44                 return false;
  45
  46         switch (boot_cpu_data.x86_model) {
  47         case INTEL_FAM6_NEHALEM:
  48         case INTEL_FAM6_NEHALEM_G:
  49         case INTEL_FAM6_NEHALEM_EP:
  50         case INTEL_FAM6_NEHALEM_EX:
  51
  52         case INTEL_FAM6_WESTMERE:
  53         case INTEL_FAM6_WESTMERE_EP:
  54         case INTEL_FAM6_WESTMERE_EX:
  55
  56         case INTEL_FAM6_SANDYBRIDGE:
  57         case INTEL_FAM6_SANDYBRIDGE_X:
  58
  59         case INTEL_FAM6_IVYBRIDGE:
  60         case INTEL_FAM6_IVYBRIDGE_X:
  61
  62         case INTEL_FAM6_HASWELL_CORE:
  63         case INTEL_FAM6_HASWELL_X:
  64         case INTEL_FAM6_HASWELL_ULT:
  65         case INTEL_FAM6_HASWELL_GT3E:
  66
  67         case INTEL_FAM6_BROADWELL_CORE:
  68         case INTEL_FAM6_BROADWELL_XEON_D:
  69         case INTEL_FAM6_BROADWELL_GT3E:
  70         case INTEL_FAM6_BROADWELL_X:
  71
  72         case INTEL_FAM6_ATOM_SILVERMONT1:
  73         case INTEL_FAM6_ATOM_SILVERMONT2:
  74         case INTEL_FAM6_ATOM_AIRMONT:
  75
  76         case INTEL_FAM6_ATOM_GOLDMONT:
  77         case INTEL_FAM6_ATOM_DENVERTON:
  78
  79         case INTEL_FAM6_ATOM_GEMINI_LAKE:
  80
  81         case INTEL_FAM6_XEON_PHI_KNL:
  82         case INTEL_FAM6_XEON_PHI_KNM:
  83                 if (idx == PERF_MSR_SMI)
  84                         return true;
  85                 break;
  86
  87         case INTEL_FAM6_SKYLAKE_MOBILE:
  88         case INTEL_FAM6_SKYLAKE_DESKTOP:
  89         case INTEL_FAM6_SKYLAKE_X:
  90         case INTEL_FAM6_KABYLAKE_MOBILE:
  91         case INTEL_FAM6_KABYLAKE_DESKTOP:
  92                 if (idx == PERF_MSR_SMI || idx == PERF_MSR_PPERF)
  93                         return true;
  94                 break;
  95         }
  96
  97         return false;
  98 }
  99
 100 struct perf_msr {
 101         u64     msr;
 102         struct  perf_pmu_events_attr *attr;
 103         bool    (*test)(int idx);
 104 };
 105
 106 PMU_EVENT_ATTR_STRING(tsc,                              evattr_tsc,             "event=0x00"    );
 107 PMU_EVENT_ATTR_STRING(aperf,                            evattr_aperf,           "event=0x01"    );
 108 PMU_EVENT_ATTR_STRING(mperf,                            evattr_mperf,           "event=0x02"    );
 109 PMU_EVENT_ATTR_STRING(pperf,                            evattr_pperf,           "event=0x03"    );
 110 PMU_EVENT_ATTR_STRING(smi,                              evattr_smi,             "event=0x04"    );
 111 PMU_EVENT_ATTR_STRING(ptsc,                             evattr_ptsc,            "event=0x05"    );
 112 PMU_EVENT_ATTR_STRING(irperf,                           evattr_irperf,          "event=0x06"    );
 113 PMU_EVENT_ATTR_STRING(cpu_thermal_margin,               evattr_therm,           "event=0x07"    );
 114 PMU_EVENT_ATTR_STRING(cpu_thermal_margin.snapshot,      evattr_therm_snap,      "1"             );
 115 PMU_EVENT_ATTR_STRING(cpu_thermal_margin.unit,          evattr_therm_unit,      "C"             );
 116
 117 static struct perf_msr msr[] = {
 118         [PERF_MSR_TSC]          = { 0,                          &evattr_tsc,            NULL,                   },
 119         [PERF_MSR_APERF]        = { MSR_IA32_APERF,             &evattr_aperf,          test_aperfmperf,        },
 120         [PERF_MSR_MPERF]        = { MSR_IA32_MPERF,             &evattr_mperf,          test_aperfmperf,        },
 121         [PERF_MSR_PPERF]        = { MSR_PPERF,                  &evattr_pperf,          test_intel,             },
 122         [PERF_MSR_SMI]          = { MSR_SMI_COUNT,              &evattr_smi,            test_intel,             },
 123         [PERF_MSR_PTSC]         = { MSR_F15H_PTSC,              &evattr_ptsc,           test_ptsc,              },
 124         [PERF_MSR_IRPERF]       = { MSR_F17H_IRPERF,            &evattr_irperf,         test_irperf,            },
 125         [PERF_MSR_THERM]        = { MSR_IA32_THERM_STATUS,      &evattr_therm,          test_therm_status,      },
 126         [PERF_MSR_THERM_SNAP]   = { MSR_IA32_THERM_STATUS,      &evattr_therm_snap,     test_therm_status,      },
 127         [PERF_MSR_THERM_UNIT]   = { MSR_IA32_THERM_STATUS,      &evattr_therm_unit,     test_therm_status,      },
 128 };
 129
 130 static struct attribute *events_attrs[PERF_MSR_EVENT_MAX + 1] = {
 131         NULL,
 132 };
 133
 134 static struct attribute_group events_attr_group = {
 135         .name = "events",
 136         .attrs = events_attrs,
 137 };
 138
 139 PMU_FORMAT_ATTR(event, "config:0-63");
 140 static struct attribute *format_attrs[] = {
 141         &format_attr_event.attr,
 142         NULL,
 143 };
 144 static struct attribute_group format_attr_group = {
 145         .name = "format",
 146         .attrs = format_attrs,
 147 };
 148
 149 static const struct attribute_group *attr_groups[] = {
 150         &events_attr_group,
 151         &format_attr_group,
 152         NULL,
 153 };
 154
 155 static int msr_event_init(struct perf_event *event)
 156 {
 157         u64 cfg = event->attr.config;
 158
 159         if (event->attr.type != event->pmu->type)
 160                 return -ENOENT;
 161
 162         /* unsupported modes and filters */
 163         if (event->attr.exclude_user   ||
 164             event->attr.exclude_kernel ||
 165             event->attr.exclude_hv     ||
 166             event->attr.exclude_idle   ||
 167             event->attr.exclude_host   ||
 168             event->attr.exclude_guest  ||
 169             event->attr.sample_period) /* no sampling */
 170                 return -EINVAL;
 171
 172         if (cfg >= PERF_MSR_EVENT_MAX)
 173                 return -EINVAL;
 174
 175         cfg = array_index_nospec((unsigned long)cfg, PERF_MSR_EVENT_MAX);
 176
 177         if (!msr[cfg].attr)
 178                 return -EINVAL;
 179
 180         event->hw.idx           = -1;
 181         event->hw.event_base    = msr[cfg].msr;
 182         event->hw.config        = cfg;
 183
 184         return 0;
 185 }
 186
 187 static inline u64 msr_read_counter(struct perf_event *event)
 188 {
 189         u64 now;
 190
 191         if (event->hw.event_base)
 192                 rdmsrl(event->hw.event_base, now);
 193         else
 194                 now = rdtsc_ordered();
 195
 196         return now;
 197 }
 198
 199 static void msr_event_update(struct perf_event *event)
 200 {
 201         u64 prev, now;
 202         s64 delta;
 203
 204         /* Careful, an NMI might modify the previous event value: */
 205 again:
 206         prev = local64_read(&event->hw.prev_count);
 207         now = msr_read_counter(event);
 208
 209         if (local64_cmpxchg(&event->hw.prev_count, prev, now) != prev)
 210                 goto again;
 211
 212         delta = now - prev;
 213         if (unlikely(event->hw.event_base == MSR_SMI_COUNT)) {
 214                 delta = sign_extend64(delta, 31);
 215                 local64_add(delta, &event->count);
 216         } else if (unlikely(event->hw.event_base == MSR_IA32_THERM_STATUS)) {
 217                 /* If valid, extract digital readout, otherwise set to -1: */
 218                 now = now & (1ULL << 31) ? (now >> 16) & 0x3f :  -1;
 219                 local64_set(&event->count, now);
 220         } else {
 221                 local64_add(delta, &event->count);
 222         }
 223 }
 224
 225 static void msr_event_start(struct perf_event *event, int flags)
 226 {
 227         u64 now = msr_read_counter(event);
 228
 229         local64_set(&event->hw.prev_count, now);
 230 }
 231
 232 static void msr_event_stop(struct perf_event *event, int flags)
 233 {
 234         msr_event_update(event);
 235 }
 236
 237 static void msr_event_del(struct perf_event *event, int flags)
 238 {
 239         msr_event_stop(event, PERF_EF_UPDATE);
 240 }
 241
 242 static int msr_event_add(struct perf_event *event, int flags)
 243 {
 244         if (flags & PERF_EF_START)
 245                 msr_event_start(event, flags);
 246
 247         return 0;
 248 }
 249
 250 static struct pmu pmu_msr = {
 251         .task_ctx_nr    = perf_sw_context,
 252         .attr_groups    = attr_groups,
 253         .event_init     = msr_event_init,
 254         .add            = msr_event_add,
 255         .del            = msr_event_del,
 256         .start          = msr_event_start,
 257         .stop           = msr_event_stop,
 258         .read           = msr_event_update,
 259         .capabilities   = PERF_PMU_CAP_NO_INTERRUPT,
 260 };
 261
 262 static int __init msr_init(void)
 263 {
 264         int i, j = 0;
 265
 266         if (!boot_cpu_has(X86_FEATURE_TSC)) {
 267                 pr_cont("no MSR PMU driver.\n");
 268                 return 0;
 269         }
 270
 271         /* Probe the MSRs. */
 272         for (i = PERF_MSR_TSC + 1; i < PERF_MSR_EVENT_MAX; i++) {
 273                 u64 val;
 274
 275                 /* Virt sucks; you cannot tell if a R/O MSR is present :/ */
 276                 if (!msr[i].test(i) || rdmsrl_safe(msr[i].msr, &val))
 277                         msr[i].attr = NULL;
 278         }
 279
 280         /* List remaining MSRs in the sysfs attrs. */
 281         for (i = 0; i < PERF_MSR_EVENT_MAX; i++) {
 282                 if (msr[i].attr)
 283                         events_attrs[j++] = &msr[i].attr->attr.attr;
 284         }
 285         events_attrs[j] = NULL;
 286
 287         perf_pmu_register(&pmu_msr, "msr", -1);
 288
 289         return 0;
 290 }
 291 device_initcall(msr_init);