git.oblomov.eu Git - linux-2.6/blob - arch/x86/kernel/cpu/perf_counter.c

   1 /*
   2  * Performance counter x86 architecture code
   3  *
   4  *  Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de>
   5  *  Copyright(C) 2008 Red Hat, Inc., Ingo Molnar
   6  *
   7  *  For licencing details see kernel-base/COPYING
   8  */
   9
  10 #include <linux/perf_counter.h>
  11 #include <linux/capability.h>
  12 #include <linux/notifier.h>
  13 #include <linux/hardirq.h>
  14 #include <linux/kprobes.h>
  15 #include <linux/module.h>
  16 #include <linux/kdebug.h>
  17 #include <linux/sched.h>
  18
  19 #include <asm/perf_counter.h>
  20 #include <asm/apic.h>
  21
  22 static bool perf_counters_initialized __read_mostly;
  23
  24 /*
  25  * Number of (generic) HW counters:
  26  */
  27 static int nr_counters_generic __read_mostly;
  28 static u64 perf_counter_mask __read_mostly;
  29 static u64 counter_value_mask __read_mostly;
  30
  31 static int nr_counters_fixed __read_mostly;
  32
  33 struct cpu_hw_counters {
  34         struct perf_counter     *counters[X86_PMC_IDX_MAX];
  35         unsigned long           used[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
  36         unsigned long           interrupts;
  37         u64                     global_enable;
  38 };
  39
  40 /*
  41  * Intel PerfMon v3. Used on Core2 and later.
  42  */
  43 static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters);
  44
  45 static const int intel_perfmon_event_map[] =
  46 {
  47   [PERF_COUNT_CPU_CYCLES]               = 0x003c,
  48   [PERF_COUNT_INSTRUCTIONS]             = 0x00c0,
  49   [PERF_COUNT_CACHE_REFERENCES]         = 0x4f2e,
  50   [PERF_COUNT_CACHE_MISSES]             = 0x412e,
  51   [PERF_COUNT_BRANCH_INSTRUCTIONS]      = 0x00c4,
  52   [PERF_COUNT_BRANCH_MISSES]            = 0x00c5,
  53   [PERF_COUNT_BUS_CYCLES]               = 0x013c,
  54 };
  55
  56 static const int max_intel_perfmon_events = ARRAY_SIZE(intel_perfmon_event_map);
  57
  58 /*
  59  * Propagate counter elapsed time into the generic counter.
  60  * Can only be executed on the CPU where the counter is active.
  61  * Returns the delta events processed.
  62  */
  63 static void
  64 x86_perf_counter_update(struct perf_counter *counter,
  65                         struct hw_perf_counter *hwc, int idx)
  66 {
  67         u64 prev_raw_count, new_raw_count, delta;
  68
  69         /*
  70          * Careful: an NMI might modify the previous counter value.
  71          *
  72          * Our tactic to handle this is to first atomically read and
  73          * exchange a new raw count - then add that new-prev delta
  74          * count to the generic counter atomically:
  75          */
  76 again:
  77         prev_raw_count = atomic64_read(&hwc->prev_count);
  78         rdmsrl(hwc->counter_base + idx, new_raw_count);
  79
  80         if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
  81                                         new_raw_count) != prev_raw_count)
  82                 goto again;
  83
  84         /*
  85          * Now we have the new raw value and have updated the prev
  86          * timestamp already. We can now calculate the elapsed delta
  87          * (counter-)time and add that to the generic counter.
  88          *
  89          * Careful, not all hw sign-extends above the physical width
  90          * of the count, so we do that by clipping the delta to 32 bits:
  91          */
  92         delta = (u64)(u32)((s32)new_raw_count - (s32)prev_raw_count);
  93
  94         atomic64_add(delta, &counter->count);
  95         atomic64_sub(delta, &hwc->period_left);
  96 }
  97
  98 /*
  99  * Setup the hardware configuration for a given hw_event_type
 100  */
 101 static int __hw_perf_counter_init(struct perf_counter *counter)
 102 {
 103         struct perf_counter_hw_event *hw_event = &counter->hw_event;
 104         struct hw_perf_counter *hwc = &counter->hw;
 105
 106         if (unlikely(!perf_counters_initialized))
 107                 return -EINVAL;
 108
 109         /*
 110          * Generate PMC IRQs:
 111          * (keep 'enabled' bit clear for now)
 112          */
 113         hwc->config = ARCH_PERFMON_EVENTSEL_INT;
 114
 115         /*
 116          * Count user and OS events unless requested not to.
 117          */
 118         if (!hw_event->exclude_user)
 119                 hwc->config |= ARCH_PERFMON_EVENTSEL_USR;
 120         if (!hw_event->exclude_kernel)
 121                 hwc->config |= ARCH_PERFMON_EVENTSEL_OS;
 122
 123         /*
 124          * If privileged enough, allow NMI events:
 125          */
 126         hwc->nmi = 0;
 127         if (capable(CAP_SYS_ADMIN) && hw_event->nmi)
 128                 hwc->nmi = 1;
 129
 130         hwc->irq_period         = hw_event->irq_period;
 131         /*
 132          * Intel PMCs cannot be accessed sanely above 32 bit width,
 133          * so we install an artificial 1<<31 period regardless of
 134          * the generic counter period:
 135          */
 136         if ((s64)hwc->irq_period <= 0 || hwc->irq_period > 0x7FFFFFFF)
 137                 hwc->irq_period = 0x7FFFFFFF;
 138
 139         atomic64_set(&hwc->period_left, hwc->irq_period);
 140
 141         /*
 142          * Raw event type provide the config in the event structure
 143          */
 144         if (hw_event->raw) {
 145                 hwc->config |= hw_event->type;
 146         } else {
 147                 if (hw_event->type >= max_intel_perfmon_events)
 148                         return -EINVAL;
 149                 /*
 150                  * The generic map:
 151                  */
 152                 hwc->config |= intel_perfmon_event_map[hw_event->type];
 153         }
 154         counter->wakeup_pending = 0;
 155
 156         return 0;
 157 }
 158
 159 u64 hw_perf_save_disable(void)
 160 {
 161         u64 ctrl;
 162
 163         if (unlikely(!perf_counters_initialized))
 164                 return 0;
 165
 166         rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
 167         wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
 168
 169         return ctrl;
 170 }
 171 EXPORT_SYMBOL_GPL(hw_perf_save_disable);
 172
 173 void hw_perf_restore(u64 ctrl)
 174 {
 175         if (unlikely(!perf_counters_initialized))
 176                 return;
 177
 178         wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
 179 }
 180 EXPORT_SYMBOL_GPL(hw_perf_restore);
 181
 182 static inline void
 183 __pmc_fixed_disable(struct perf_counter *counter,
 184                     struct hw_perf_counter *hwc, unsigned int __idx)
 185 {
 186         int idx = __idx - X86_PMC_IDX_FIXED;
 187         u64 ctrl_val, mask;
 188         int err;
 189
 190         mask = 0xfULL << (idx * 4);
 191
 192         rdmsrl(hwc->config_base, ctrl_val);
 193         ctrl_val &= ~mask;
 194         err = checking_wrmsrl(hwc->config_base, ctrl_val);
 195 }
 196
 197 static inline void
 198 __pmc_generic_disable(struct perf_counter *counter,
 199                            struct hw_perf_counter *hwc, unsigned int idx)
 200 {
 201         if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL))
 202                 __pmc_fixed_disable(counter, hwc, idx);
 203         else
 204                 wrmsr_safe(hwc->config_base + idx, hwc->config, 0);
 205 }
 206
 207 static DEFINE_PER_CPU(u64, prev_left[X86_PMC_IDX_MAX]);
 208
 209 /*
 210  * Set the next IRQ period, based on the hwc->period_left value.
 211  * To be called with the counter disabled in hw:
 212  */
 213 static void
 214 __hw_perf_counter_set_period(struct perf_counter *counter,
 215                              struct hw_perf_counter *hwc, int idx)
 216 {
 217         s64 left = atomic64_read(&hwc->period_left);
 218         s32 period = hwc->irq_period;
 219         int err;
 220
 221         /*
 222          * If we are way outside a reasoable range then just skip forward:
 223          */
 224         if (unlikely(left <= -period)) {
 225                 left = period;
 226                 atomic64_set(&hwc->period_left, left);
 227         }
 228
 229         if (unlikely(left <= 0)) {
 230                 left += period;
 231                 atomic64_set(&hwc->period_left, left);
 232         }
 233
 234         per_cpu(prev_left[idx], smp_processor_id()) = left;
 235
 236         /*
 237          * The hw counter starts counting from this counter offset,
 238          * mark it to be able to extra future deltas:
 239          */
 240         atomic64_set(&hwc->prev_count, (u64)-left);
 241
 242         err = checking_wrmsrl(hwc->counter_base + idx,
 243                              (u64)(-left) & counter_value_mask);
 244 }
 245
 246 static inline void
 247 __pmc_fixed_enable(struct perf_counter *counter,
 248                    struct hw_perf_counter *hwc, unsigned int __idx)
 249 {
 250         int idx = __idx - X86_PMC_IDX_FIXED;
 251         u64 ctrl_val, bits, mask;
 252         int err;
 253
 254         /*
 255          * Enable IRQ generation (0x8),
 256          * and enable ring-3 counting (0x2) and ring-0 counting (0x1)
 257          * if requested:
 258          */
 259         bits = 0x8ULL;
 260         if (hwc->config & ARCH_PERFMON_EVENTSEL_USR)
 261                 bits |= 0x2;
 262         if (hwc->config & ARCH_PERFMON_EVENTSEL_OS)
 263                 bits |= 0x1;
 264         bits <<= (idx * 4);
 265         mask = 0xfULL << (idx * 4);
 266
 267         rdmsrl(hwc->config_base, ctrl_val);
 268         ctrl_val &= ~mask;
 269         ctrl_val |= bits;
 270         err = checking_wrmsrl(hwc->config_base, ctrl_val);
 271 }
 272
 273 static void
 274 __pmc_generic_enable(struct perf_counter *counter,
 275                           struct hw_perf_counter *hwc, int idx)
 276 {
 277         if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL))
 278                 __pmc_fixed_enable(counter, hwc, idx);
 279         else
 280                 wrmsr(hwc->config_base + idx,
 281                       hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE, 0);
 282 }
 283
 284 static int
 285 fixed_mode_idx(struct perf_counter *counter, struct hw_perf_counter *hwc)
 286 {
 287         unsigned int event;
 288
 289         if (unlikely(hwc->nmi))
 290                 return -1;
 291
 292         event = hwc->config & ARCH_PERFMON_EVENT_MASK;
 293
 294         if (unlikely(event == intel_perfmon_event_map[PERF_COUNT_INSTRUCTIONS]))
 295                 return X86_PMC_IDX_FIXED_INSTRUCTIONS;
 296         if (unlikely(event == intel_perfmon_event_map[PERF_COUNT_CPU_CYCLES]))
 297                 return X86_PMC_IDX_FIXED_CPU_CYCLES;
 298         if (unlikely(event == intel_perfmon_event_map[PERF_COUNT_BUS_CYCLES]))
 299                 return X86_PMC_IDX_FIXED_BUS_CYCLES;
 300
 301         return -1;
 302 }
 303
 304 /*
 305  * Find a PMC slot for the freshly enabled / scheduled in counter:
 306  */
 307 static int pmc_generic_enable(struct perf_counter *counter)
 308 {
 309         struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
 310         struct hw_perf_counter *hwc = &counter->hw;
 311         int idx;
 312
 313         idx = fixed_mode_idx(counter, hwc);
 314         if (idx >= 0) {
 315                 /*
 316                  * Try to get the fixed counter, if that is already taken
 317                  * then try to get a generic counter:
 318                  */
 319                 if (test_and_set_bit(idx, cpuc->used))
 320                         goto try_generic;
 321
 322                 hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
 323                 /*
 324                  * We set it so that counter_base + idx in wrmsr/rdmsr maps to
 325                  * MSR_ARCH_PERFMON_FIXED_CTR0 ... CTR2:
 326                  */
 327                 hwc->counter_base =
 328                         MSR_ARCH_PERFMON_FIXED_CTR0 - X86_PMC_IDX_FIXED;
 329                 hwc->idx = idx;
 330         } else {
 331                 idx = hwc->idx;
 332                 /* Try to get the previous generic counter again */
 333                 if (test_and_set_bit(idx, cpuc->used)) {
 334 try_generic:
 335                         idx = find_first_zero_bit(cpuc->used, nr_counters_generic);
 336                         if (idx == nr_counters_generic)
 337                                 return -EAGAIN;
 338
 339                         set_bit(idx, cpuc->used);
 340                         hwc->idx = idx;
 341                 }
 342                 hwc->config_base  = MSR_ARCH_PERFMON_EVENTSEL0;
 343                 hwc->counter_base = MSR_ARCH_PERFMON_PERFCTR0;
 344         }
 345
 346         perf_counters_lapic_init(hwc->nmi);
 347
 348         __pmc_generic_disable(counter, hwc, idx);
 349
 350         cpuc->counters[idx] = counter;
 351         /*
 352          * Make it visible before enabling the hw:
 353          */
 354         smp_wmb();
 355
 356         __hw_perf_counter_set_period(counter, hwc, idx);
 357         __pmc_generic_enable(counter, hwc, idx);
 358
 359         return 0;
 360 }
 361
 362 void perf_counter_print_debug(void)
 363 {
 364         u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed;
 365         struct cpu_hw_counters *cpuc;
 366         int cpu, idx;
 367
 368         if (!nr_counters_generic)
 369                 return;
 370
 371         local_irq_disable();
 372
 373         cpu = smp_processor_id();
 374         cpuc = &per_cpu(cpu_hw_counters, cpu);
 375
 376         rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
 377         rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
 378         rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow);
 379         rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, fixed);
 380
 381         printk(KERN_INFO "\n");
 382         printk(KERN_INFO "CPU#%d: ctrl:       %016llx\n", cpu, ctrl);
 383         printk(KERN_INFO "CPU#%d: status:     %016llx\n", cpu, status);
 384         printk(KERN_INFO "CPU#%d: overflow:   %016llx\n", cpu, overflow);
 385         printk(KERN_INFO "CPU#%d: fixed:      %016llx\n", cpu, fixed);
 386         printk(KERN_INFO "CPU#%d: used:       %016llx\n", cpu, *(u64 *)cpuc->used);
 387
 388         for (idx = 0; idx < nr_counters_generic; idx++) {
 389                 rdmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + idx, pmc_ctrl);
 390                 rdmsrl(MSR_ARCH_PERFMON_PERFCTR0  + idx, pmc_count);
 391
 392                 prev_left = per_cpu(prev_left[idx], cpu);
 393
 394                 printk(KERN_INFO "CPU#%d:   gen-PMC%d ctrl:  %016llx\n",
 395                         cpu, idx, pmc_ctrl);
 396                 printk(KERN_INFO "CPU#%d:   gen-PMC%d count: %016llx\n",
 397                         cpu, idx, pmc_count);
 398                 printk(KERN_INFO "CPU#%d:   gen-PMC%d left:  %016llx\n",
 399                         cpu, idx, prev_left);
 400         }
 401         for (idx = 0; idx < nr_counters_fixed; idx++) {
 402                 rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count);
 403
 404                 printk(KERN_INFO "CPU#%d: fixed-PMC%d count: %016llx\n",
 405                         cpu, idx, pmc_count);
 406         }
 407         local_irq_enable();
 408 }
 409
 410 static void pmc_generic_disable(struct perf_counter *counter)
 411 {
 412         struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
 413         struct hw_perf_counter *hwc = &counter->hw;
 414         unsigned int idx = hwc->idx;
 415
 416         __pmc_generic_disable(counter, hwc, idx);
 417
 418         clear_bit(idx, cpuc->used);
 419         cpuc->counters[idx] = NULL;
 420         /*
 421          * Make sure the cleared pointer becomes visible before we
 422          * (potentially) free the counter:
 423          */
 424         smp_wmb();
 425
 426         /*
 427          * Drain the remaining delta count out of a counter
 428          * that we are disabling:
 429          */
 430         x86_perf_counter_update(counter, hwc, idx);
 431 }
 432
 433 static void perf_store_irq_data(struct perf_counter *counter, u64 data)
 434 {
 435         struct perf_data *irqdata = counter->irqdata;
 436
 437         if (irqdata->len > PERF_DATA_BUFLEN - sizeof(u64)) {
 438                 irqdata->overrun++;
 439         } else {
 440                 u64 *p = (u64 *) &irqdata->data[irqdata->len];
 441
 442                 *p = data;
 443                 irqdata->len += sizeof(u64);
 444         }
 445 }
 446
 447 /*
 448  * Save and restart an expired counter. Called by NMI contexts,
 449  * so it has to be careful about preempting normal counter ops:
 450  */
 451 static void perf_save_and_restart(struct perf_counter *counter)
 452 {
 453         struct hw_perf_counter *hwc = &counter->hw;
 454         int idx = hwc->idx;
 455
 456         x86_perf_counter_update(counter, hwc, idx);
 457         __hw_perf_counter_set_period(counter, hwc, idx);
 458
 459         if (counter->state == PERF_COUNTER_STATE_ACTIVE)
 460                 __pmc_generic_enable(counter, hwc, idx);
 461 }
 462
 463 static void
 464 perf_handle_group(struct perf_counter *sibling, u64 *status, u64 *overflown)
 465 {
 466         struct perf_counter *counter, *group_leader = sibling->group_leader;
 467
 468         /*
 469          * Store sibling timestamps (if any):
 470          */
 471         list_for_each_entry(counter, &group_leader->sibling_list, list_entry) {
 472
 473                 x86_perf_counter_update(counter, &counter->hw, counter->hw.idx);
 474                 perf_store_irq_data(sibling, counter->hw_event.type);
 475                 perf_store_irq_data(sibling, atomic64_read(&counter->count));
 476         }
 477 }
 478
 479 /*
 480  * Maximum interrupt frequency of 100KHz per CPU
 481  */
 482 #define PERFMON_MAX_INTERRUPTS 100000/HZ
 483
 484 /*
 485  * This handler is triggered by the local APIC, so the APIC IRQ handling
 486  * rules apply:
 487  */
 488 static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi)
 489 {
 490         int bit, cpu = smp_processor_id();
 491         u64 ack, status;
 492         struct cpu_hw_counters *cpuc = &per_cpu(cpu_hw_counters, cpu);
 493
 494         rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
 495
 496         /* Disable counters globally */
 497         wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
 498         ack_APIC_irq();
 499
 500         rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
 501         if (!status)
 502                 goto out;
 503
 504 again:
 505         inc_irq_stat(apic_perf_irqs);
 506         ack = status;
 507         for_each_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
 508                 struct perf_counter *counter = cpuc->counters[bit];
 509
 510                 clear_bit(bit, (unsigned long *) &status);
 511                 if (!counter)
 512                         continue;
 513
 514                 perf_save_and_restart(counter);
 515
 516                 switch (counter->hw_event.record_type) {
 517                 case PERF_RECORD_SIMPLE:
 518                         continue;
 519                 case PERF_RECORD_IRQ:
 520                         perf_store_irq_data(counter, instruction_pointer(regs));
 521                         break;
 522                 case PERF_RECORD_GROUP:
 523                         perf_handle_group(counter, &status, &ack);
 524                         break;
 525                 }
 526                 /*
 527                  * From NMI context we cannot call into the scheduler to
 528                  * do a task wakeup - but we mark these generic as
 529                  * wakeup_pending and initate a wakeup callback:
 530                  */
 531                 if (nmi) {
 532                         counter->wakeup_pending = 1;
 533                         set_tsk_thread_flag(current, TIF_PERF_COUNTERS);
 534                 } else {
 535                         wake_up(&counter->waitq);
 536                 }
 537         }
 538
 539         wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack);
 540
 541         /*
 542          * Repeat if there is more work to be done:
 543          */
 544         rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
 545         if (status)
 546                 goto again;
 547 out:
 548         /*
 549          * Restore - do not reenable when global enable is off or throttled:
 550          */
 551         if (++cpuc->interrupts < PERFMON_MAX_INTERRUPTS)
 552                 wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
 553 }
 554
 555 void perf_counter_unthrottle(void)
 556 {
 557         struct cpu_hw_counters *cpuc;
 558         u64 global_enable;
 559
 560         if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
 561                 return;
 562
 563         if (unlikely(!perf_counters_initialized))
 564                 return;
 565
 566         cpuc = &per_cpu(cpu_hw_counters, smp_processor_id());
 567         if (cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) {
 568                 if (printk_ratelimit())
 569                         printk(KERN_WARNING "PERFMON: max interrupts exceeded!\n");
 570                 wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
 571         }
 572         rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, global_enable);
 573         if (unlikely(cpuc->global_enable && !global_enable))
 574                 wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable);
 575         cpuc->interrupts = 0;
 576 }
 577
 578 void smp_perf_counter_interrupt(struct pt_regs *regs)
 579 {
 580         irq_enter();
 581         apic_write(APIC_LVTPC, LOCAL_PERF_VECTOR);
 582         __smp_perf_counter_interrupt(regs, 0);
 583
 584         irq_exit();
 585 }
 586
 587 /*
 588  * This handler is triggered by NMI contexts:
 589  */
 590 void perf_counter_notify(struct pt_regs *regs)
 591 {
 592         struct cpu_hw_counters *cpuc;
 593         unsigned long flags;
 594         int bit, cpu;
 595
 596         local_irq_save(flags);
 597         cpu = smp_processor_id();
 598         cpuc = &per_cpu(cpu_hw_counters, cpu);
 599
 600         for_each_bit(bit, cpuc->used, X86_PMC_IDX_MAX) {
 601                 struct perf_counter *counter = cpuc->counters[bit];
 602
 603                 if (!counter)
 604                         continue;
 605
 606                 if (counter->wakeup_pending) {
 607                         counter->wakeup_pending = 0;
 608                         wake_up(&counter->waitq);
 609                 }
 610         }
 611
 612         local_irq_restore(flags);
 613 }
 614
 615 void perf_counters_lapic_init(int nmi)
 616 {
 617         u32 apic_val;
 618
 619         if (!perf_counters_initialized)
 620                 return;
 621         /*
 622          * Enable the performance counter vector in the APIC LVT:
 623          */
 624         apic_val = apic_read(APIC_LVTERR);
 625
 626         apic_write(APIC_LVTERR, apic_val | APIC_LVT_MASKED);
 627         if (nmi)
 628                 apic_write(APIC_LVTPC, APIC_DM_NMI);
 629         else
 630                 apic_write(APIC_LVTPC, LOCAL_PERF_VECTOR);
 631         apic_write(APIC_LVTERR, apic_val);
 632 }
 633
 634 static int __kprobes
 635 perf_counter_nmi_handler(struct notifier_block *self,
 636                          unsigned long cmd, void *__args)
 637 {
 638         struct die_args *args = __args;
 639         struct pt_regs *regs;
 640
 641         if (likely(cmd != DIE_NMI_IPI))
 642                 return NOTIFY_DONE;
 643
 644         regs = args->regs;
 645
 646         apic_write(APIC_LVTPC, APIC_DM_NMI);
 647         __smp_perf_counter_interrupt(regs, 1);
 648
 649         return NOTIFY_STOP;
 650 }
 651
 652 static __read_mostly struct notifier_block perf_counter_nmi_notifier = {
 653         .notifier_call          = perf_counter_nmi_handler,
 654         .next                   = NULL,
 655         .priority               = 1
 656 };
 657
 658 void __init init_hw_perf_counters(void)
 659 {
 660         union cpuid10_eax eax;
 661         unsigned int ebx;
 662         unsigned int unused;
 663         union cpuid10_edx edx;
 664
 665         if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
 666                 return;
 667
 668         /*
 669          * Check whether the Architectural PerfMon supports
 670          * Branch Misses Retired Event or not.
 671          */
 672         cpuid(10, &eax.full, &ebx, &unused, &edx.full);
 673         if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED)
 674                 return;
 675
 676         printk(KERN_INFO "Intel Performance Monitoring support detected.\n");
 677
 678         printk(KERN_INFO "... version:         %d\n", eax.split.version_id);
 679         printk(KERN_INFO "... num counters:    %d\n", eax.split.num_counters);
 680         nr_counters_generic = eax.split.num_counters;
 681         if (nr_counters_generic > X86_PMC_MAX_GENERIC) {
 682                 nr_counters_generic = X86_PMC_MAX_GENERIC;
 683                 WARN(1, KERN_ERR "hw perf counters %d > max(%d), clipping!",
 684                         nr_counters_generic, X86_PMC_MAX_GENERIC);
 685         }
 686         perf_counter_mask = (1 << nr_counters_generic) - 1;
 687         perf_max_counters = nr_counters_generic;
 688
 689         printk(KERN_INFO "... bit width:       %d\n", eax.split.bit_width);
 690         counter_value_mask = (1ULL << eax.split.bit_width) - 1;
 691         printk(KERN_INFO "... value mask:      %016Lx\n", counter_value_mask);
 692
 693         printk(KERN_INFO "... mask length:     %d\n", eax.split.mask_length);
 694
 695         nr_counters_fixed = edx.split.num_counters_fixed;
 696         if (nr_counters_fixed > X86_PMC_MAX_FIXED) {
 697                 nr_counters_fixed = X86_PMC_MAX_FIXED;
 698                 WARN(1, KERN_ERR "hw perf counters fixed %d > max(%d), clipping!",
 699                         nr_counters_fixed, X86_PMC_MAX_FIXED);
 700         }
 701         printk(KERN_INFO "... fixed counters:  %d\n", nr_counters_fixed);
 702
 703         perf_counter_mask |= ((1LL << nr_counters_fixed)-1) << X86_PMC_IDX_FIXED;
 704
 705         printk(KERN_INFO "... counter mask:    %016Lx\n", perf_counter_mask);
 706         perf_counters_initialized = true;
 707
 708         perf_counters_lapic_init(0);
 709         register_die_notifier(&perf_counter_nmi_notifier);
 710 }
 711
 712 static void pmc_generic_read(struct perf_counter *counter)
 713 {
 714         x86_perf_counter_update(counter, &counter->hw, counter->hw.idx);
 715 }
 716
 717 static const struct hw_perf_counter_ops x86_perf_counter_ops = {
 718         .enable         = pmc_generic_enable,
 719         .disable        = pmc_generic_disable,
 720         .read           = pmc_generic_read,
 721 };
 722
 723 const struct hw_perf_counter_ops *
 724 hw_perf_counter_init(struct perf_counter *counter)
 725 {
 726         int err;
 727
 728         err = __hw_perf_counter_init(counter);
 729         if (err)
 730                 return NULL;
 731
 732         return &x86_perf_counter_ops;
 733 }