arch/xtensa/kernel/perf_event.c

   1 /*
   2  * Xtensa Performance Monitor Module driver
   3  * See Tensilica Debug User's Guide for PMU registers documentation.
   4  *
   5  * Copyright (C) 2015 Cadence Design Systems Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/interrupt.h>
  13 #include <linux/irqdomain.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/perf_event.h>
  17 #include <linux/platform_device.h>
  18
  19 #include <asm/processor.h>
  20 #include <asm/stacktrace.h>
  21
  22 /* Global control/status for all perf counters */
  23 #define XTENSA_PMU_PMG                  0x1000
  24 /* Perf counter values */
  25 #define XTENSA_PMU_PM(i)                (0x1080 + (i) * 4)
  26 /* Perf counter control registers */
  27 #define XTENSA_PMU_PMCTRL(i)            (0x1100 + (i) * 4)
  28 /* Perf counter status registers */
  29 #define XTENSA_PMU_PMSTAT(i)            (0x1180 + (i) * 4)
  30
  31 #define XTENSA_PMU_PMG_PMEN             0x1
  32
  33 #define XTENSA_PMU_COUNTER_MASK         0xffffffffULL
  34 #define XTENSA_PMU_COUNTER_MAX          0x7fffffff
  35
  36 #define XTENSA_PMU_PMCTRL_INTEN         0x00000001
  37 #define XTENSA_PMU_PMCTRL_KRNLCNT       0x00000008
  38 #define XTENSA_PMU_PMCTRL_TRACELEVEL    0x000000f0
  39 #define XTENSA_PMU_PMCTRL_SELECT_SHIFT  8
  40 #define XTENSA_PMU_PMCTRL_SELECT        0x00001f00
  41 #define XTENSA_PMU_PMCTRL_MASK_SHIFT    16
  42 #define XTENSA_PMU_PMCTRL_MASK          0xffff0000
  43
  44 #define XTENSA_PMU_MASK(select, mask) \
  45         (((select) << XTENSA_PMU_PMCTRL_SELECT_SHIFT) | \
  46          ((mask) << XTENSA_PMU_PMCTRL_MASK_SHIFT) | \
  47          XTENSA_PMU_PMCTRL_TRACELEVEL | \
  48          XTENSA_PMU_PMCTRL_INTEN)
  49
  50 #define XTENSA_PMU_PMSTAT_OVFL          0x00000001
  51 #define XTENSA_PMU_PMSTAT_INTASRT       0x00000010
  52
  53 struct xtensa_pmu_events {
  54         /* Array of events currently on this core */
  55         struct perf_event *event[XCHAL_NUM_PERF_COUNTERS];
  56         /* Bitmap of used hardware counters */
  57         unsigned long used_mask[BITS_TO_LONGS(XCHAL_NUM_PERF_COUNTERS)];
  58 };
  59 static DEFINE_PER_CPU(struct xtensa_pmu_events, xtensa_pmu_events);
  60
  61 static const u32 xtensa_hw_ctl[] = {
  62         [PERF_COUNT_HW_CPU_CYCLES]              = XTENSA_PMU_MASK(0, 0x1),
  63         [PERF_COUNT_HW_INSTRUCTIONS]            = XTENSA_PMU_MASK(2, 0xffff),
  64         [PERF_COUNT_HW_CACHE_REFERENCES]        = XTENSA_PMU_MASK(10, 0x1),
  65         [PERF_COUNT_HW_CACHE_MISSES]            = XTENSA_PMU_MASK(12, 0x1),
  66         /* Taken and non-taken branches + taken loop ends */
  67         [PERF_COUNT_HW_BRANCH_INSTRUCTIONS]     = XTENSA_PMU_MASK(2, 0x490),
  68         /* Instruction-related + other global stall cycles */
  69         [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = XTENSA_PMU_MASK(4, 0x1ff),
  70         /* Data-related global stall cycles */
  71         [PERF_COUNT_HW_STALLED_CYCLES_BACKEND]  = XTENSA_PMU_MASK(3, 0x1ff),
  72 };
  73
  74 #define C(_x) PERF_COUNT_HW_CACHE_##_x
  75
  76 static const u32 xtensa_cache_ctl[][C(OP_MAX)][C(RESULT_MAX)] = {
  77         [C(L1D)] = {
  78                 [C(OP_READ)] = {
  79                         [C(RESULT_ACCESS)]      = XTENSA_PMU_MASK(10, 0x1),
  80                         [C(RESULT_MISS)]        = XTENSA_PMU_MASK(10, 0x2),
  81                 },
  82                 [C(OP_WRITE)] = {
  83                         [C(RESULT_ACCESS)]      = XTENSA_PMU_MASK(11, 0x1),
  84                         [C(RESULT_MISS)]        = XTENSA_PMU_MASK(11, 0x2),
  85                 },
  86         },
  87         [C(L1I)] = {
  88                 [C(OP_READ)] = {
  89                         [C(RESULT_ACCESS)]      = XTENSA_PMU_MASK(8, 0x1),
  90                         [C(RESULT_MISS)]        = XTENSA_PMU_MASK(8, 0x2),
  91                 },
  92         },
  93         [C(DTLB)] = {
  94                 [C(OP_READ)] = {
  95                         [C(RESULT_ACCESS)]      = XTENSA_PMU_MASK(9, 0x1),
  96                         [C(RESULT_MISS)]        = XTENSA_PMU_MASK(9, 0x8),
  97                 },
  98         },
  99         [C(ITLB)] = {
 100                 [C(OP_READ)] = {
 101                         [C(RESULT_ACCESS)]      = XTENSA_PMU_MASK(7, 0x1),
 102                         [C(RESULT_MISS)]        = XTENSA_PMU_MASK(7, 0x8),
 103                 },
 104         },
 105 };
 106
 107 static int xtensa_pmu_cache_event(u64 config)
 108 {
 109         unsigned int cache_type, cache_op, cache_result;
 110         int ret;
 111
 112         cache_type = (config >>  0) & 0xff;
 113         cache_op = (config >>  8) & 0xff;
 114         cache_result = (config >> 16) & 0xff;
 115
 116         if (cache_type >= ARRAY_SIZE(xtensa_cache_ctl) ||
 117             cache_op >= C(OP_MAX) ||
 118             cache_result >= C(RESULT_MAX))
 119                 return -EINVAL;
 120
 121         ret = xtensa_cache_ctl[cache_type][cache_op][cache_result];
 122
 123         if (ret == 0)
 124                 return -EINVAL;
 125
 126         return ret;
 127 }
 128
 129 static inline uint32_t xtensa_pmu_read_counter(int idx)
 130 {
 131         return get_er(XTENSA_PMU_PM(idx));
 132 }
 133
 134 static inline void xtensa_pmu_write_counter(int idx, uint32_t v)
 135 {
 136         set_er(v, XTENSA_PMU_PM(idx));
 137 }
 138
 139 static void xtensa_perf_event_update(struct perf_event *event,
 140                                      struct hw_perf_event *hwc, int idx)
 141 {
 142         uint64_t prev_raw_count, new_raw_count;
 143         int64_t delta;
 144
 145         do {
 146                 prev_raw_count = local64_read(&hwc->prev_count);
 147                 new_raw_count = xtensa_pmu_read_counter(event->hw.idx);
 148         } while (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
 149                                  new_raw_count) != prev_raw_count);
 150
 151         delta = (new_raw_count - prev_raw_count) & XTENSA_PMU_COUNTER_MASK;
 152
 153         local64_add(delta, &event->count);
 154         local64_sub(delta, &hwc->period_left);
 155 }
 156
 157 static bool xtensa_perf_event_set_period(struct perf_event *event,
 158                                          struct hw_perf_event *hwc, int idx)
 159 {
 160         bool rc = false;
 161         s64 left;
 162
 163         if (!is_sampling_event(event)) {
 164                 left = XTENSA_PMU_COUNTER_MAX;
 165         } else {
 166                 s64 period = hwc->sample_period;
 167
 168                 left = local64_read(&hwc->period_left);
 169                 if (left <= -period) {
 170                         left = period;
 171                         local64_set(&hwc->period_left, left);
 172                         hwc->last_period = period;
 173                         rc = true;
 174                 } else if (left <= 0) {
 175                         left += period;
 176                         local64_set(&hwc->period_left, left);
 177                         hwc->last_period = period;
 178                         rc = true;
 179                 }
 180                 if (left > XTENSA_PMU_COUNTER_MAX)
 181                         left = XTENSA_PMU_COUNTER_MAX;
 182         }
 183
 184         local64_set(&hwc->prev_count, -left);
 185         xtensa_pmu_write_counter(idx, -left);
 186         perf_event_update_userpage(event);
 187
 188         return rc;
 189 }
 190
 191 static void xtensa_pmu_enable(struct pmu *pmu)
 192 {
 193         set_er(get_er(XTENSA_PMU_PMG) | XTENSA_PMU_PMG_PMEN, XTENSA_PMU_PMG);
 194 }
 195
 196 static void xtensa_pmu_disable(struct pmu *pmu)
 197 {
 198         set_er(get_er(XTENSA_PMU_PMG) & ~XTENSA_PMU_PMG_PMEN, XTENSA_PMU_PMG);
 199 }
 200
 201 static int xtensa_pmu_event_init(struct perf_event *event)
 202 {
 203         int ret;
 204
 205         switch (event->attr.type) {
 206         case PERF_TYPE_HARDWARE:
 207                 if (event->attr.config >= ARRAY_SIZE(xtensa_hw_ctl) ||
 208                     xtensa_hw_ctl[event->attr.config] == 0)
 209                         return -EINVAL;
 210                 event->hw.config = xtensa_hw_ctl[event->attr.config];
 211                 return 0;
 212
 213         case PERF_TYPE_HW_CACHE:
 214                 ret = xtensa_pmu_cache_event(event->attr.config);
 215                 if (ret < 0)
 216                         return ret;
 217                 event->hw.config = ret;
 218                 return 0;
 219
 220         case PERF_TYPE_RAW:
 221                 /* Not 'previous counter' select */
 222                 if ((event->attr.config & XTENSA_PMU_PMCTRL_SELECT) ==
 223                     (1 << XTENSA_PMU_PMCTRL_SELECT_SHIFT))
 224                         return -EINVAL;
 225                 event->hw.config = (event->attr.config &
 226                                     (XTENSA_PMU_PMCTRL_KRNLCNT |
 227                                      XTENSA_PMU_PMCTRL_TRACELEVEL |
 228                                      XTENSA_PMU_PMCTRL_SELECT |
 229                                      XTENSA_PMU_PMCTRL_MASK)) |
 230                         XTENSA_PMU_PMCTRL_INTEN;
 231                 return 0;
 232
 233         default:
 234                 return -ENOENT;
 235         }
 236 }
 237
 238 /*
 239  * Starts/Stops a counter present on the PMU. The PMI handler
 240  * should stop the counter when perf_event_overflow() returns
 241  * !0. ->start() will be used to continue.
 242  */
 243 static void xtensa_pmu_start(struct perf_event *event, int flags)
 244 {
 245         struct hw_perf_event *hwc = &event->hw;
 246         int idx = hwc->idx;
 247
 248         if (WARN_ON_ONCE(idx == -1))
 249                 return;
 250
 251         if (flags & PERF_EF_RELOAD) {
 252                 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
 253                 xtensa_perf_event_set_period(event, hwc, idx);
 254         }
 255
 256         hwc->state = 0;
 257
 258         set_er(hwc->config, XTENSA_PMU_PMCTRL(idx));
 259 }
 260
 261 static void xtensa_pmu_stop(struct perf_event *event, int flags)
 262 {
 263         struct hw_perf_event *hwc = &event->hw;
 264         int idx = hwc->idx;
 265
 266         if (!(hwc->state & PERF_HES_STOPPED)) {
 267                 set_er(0, XTENSA_PMU_PMCTRL(idx));
 268                 set_er(get_er(XTENSA_PMU_PMSTAT(idx)),
 269                        XTENSA_PMU_PMSTAT(idx));
 270                 hwc->state |= PERF_HES_STOPPED;
 271         }
 272
 273         if ((flags & PERF_EF_UPDATE) &&
 274             !(event->hw.state & PERF_HES_UPTODATE)) {
 275                 xtensa_perf_event_update(event, &event->hw, idx);
 276                 event->hw.state |= PERF_HES_UPTODATE;
 277         }
 278 }
 279
 280 /*
 281  * Adds/Removes a counter to/from the PMU, can be done inside
 282  * a transaction, see the ->*_txn() methods.
 283  */
 284 static int xtensa_pmu_add(struct perf_event *event, int flags)
 285 {
 286         struct xtensa_pmu_events *ev = this_cpu_ptr(&xtensa_pmu_events);
 287         struct hw_perf_event *hwc = &event->hw;
 288         int idx = hwc->idx;
 289
 290         if (__test_and_set_bit(idx, ev->used_mask)) {
 291                 idx = find_first_zero_bit(ev->used_mask,
 292                                           XCHAL_NUM_PERF_COUNTERS);
 293                 if (idx == XCHAL_NUM_PERF_COUNTERS)
 294                         return -EAGAIN;
 295
 296                 __set_bit(idx, ev->used_mask);
 297                 hwc->idx = idx;
 298         }
 299         ev->event[idx] = event;
 300
 301         hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
 302
 303         if (flags & PERF_EF_START)
 304                 xtensa_pmu_start(event, PERF_EF_RELOAD);
 305
 306         perf_event_update_userpage(event);
 307         return 0;
 308 }
 309
 310 static void xtensa_pmu_del(struct perf_event *event, int flags)
 311 {
 312         struct xtensa_pmu_events *ev = this_cpu_ptr(&xtensa_pmu_events);
 313
 314         xtensa_pmu_stop(event, PERF_EF_UPDATE);
 315         __clear_bit(event->hw.idx, ev->used_mask);
 316         perf_event_update_userpage(event);
 317 }
 318
 319 static void xtensa_pmu_read(struct perf_event *event)
 320 {
 321         xtensa_perf_event_update(event, &event->hw, event->hw.idx);
 322 }
 323
 324 static int callchain_trace(struct stackframe *frame, void *data)
 325 {
 326         struct perf_callchain_entry_ctx *entry = data;
 327
 328         perf_callchain_store(entry, frame->pc);
 329         return 0;
 330 }
 331
 332 void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
 333                            struct pt_regs *regs)
 334 {
 335         xtensa_backtrace_kernel(regs, entry->max_stack,
 336                                 callchain_trace, NULL, entry);
 337 }
 338
 339 void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
 340                          struct pt_regs *regs)
 341 {
 342         xtensa_backtrace_user(regs, entry->max_stack,
 343                               callchain_trace, entry);
 344 }
 345
 346 void perf_event_print_debug(void)
 347 {
 348         unsigned long flags;
 349         unsigned i;
 350
 351         local_irq_save(flags);
 352         pr_info("CPU#%d: PMG: 0x%08lx\n", smp_processor_id(),
 353                 get_er(XTENSA_PMU_PMG));
 354         for (i = 0; i < XCHAL_NUM_PERF_COUNTERS; ++i)
 355                 pr_info("PM%d: 0x%08lx, PMCTRL%d: 0x%08lx, PMSTAT%d: 0x%08lx\n",
 356                         i, get_er(XTENSA_PMU_PM(i)),
 357                         i, get_er(XTENSA_PMU_PMCTRL(i)),
 358                         i, get_er(XTENSA_PMU_PMSTAT(i)));
 359         local_irq_restore(flags);
 360 }
 361
 362 irqreturn_t xtensa_pmu_irq_handler(int irq, void *dev_id)
 363 {
 364         irqreturn_t rc = IRQ_NONE;
 365         struct xtensa_pmu_events *ev = this_cpu_ptr(&xtensa_pmu_events);
 366         unsigned i;
 367
 368         for (i = find_first_bit(ev->used_mask, XCHAL_NUM_PERF_COUNTERS);
 369              i < XCHAL_NUM_PERF_COUNTERS;
 370              i = find_next_bit(ev->used_mask, XCHAL_NUM_PERF_COUNTERS, i + 1)) {
 371                 uint32_t v = get_er(XTENSA_PMU_PMSTAT(i));
 372                 struct perf_event *event = ev->event[i];
 373                 struct hw_perf_event *hwc = &event->hw;
 374                 u64 last_period;
 375
 376                 if (!(v & XTENSA_PMU_PMSTAT_OVFL))
 377                         continue;
 378
 379                 set_er(v, XTENSA_PMU_PMSTAT(i));
 380                 xtensa_perf_event_update(event, hwc, i);
 381                 last_period = hwc->last_period;
 382                 if (xtensa_perf_event_set_period(event, hwc, i)) {
 383                         struct perf_sample_data data;
 384                         struct pt_regs *regs = get_irq_regs();
 385
 386                         perf_sample_data_init(&data, 0, last_period);
 387                         if (perf_event_overflow(event, &data, regs))
 388                                 xtensa_pmu_stop(event, 0);
 389                 }
 390
 391                 rc = IRQ_HANDLED;
 392         }
 393         return rc;
 394 }
 395
 396 static struct pmu xtensa_pmu = {
 397         .pmu_enable = xtensa_pmu_enable,
 398         .pmu_disable = xtensa_pmu_disable,
 399         .event_init = xtensa_pmu_event_init,
 400         .add = xtensa_pmu_add,
 401         .del = xtensa_pmu_del,
 402         .start = xtensa_pmu_start,
 403         .stop = xtensa_pmu_stop,
 404         .read = xtensa_pmu_read,
 405 };
 406
 407 static int xtensa_pmu_setup(int cpu)
 408 {
 409         unsigned i;
 410
 411         set_er(0, XTENSA_PMU_PMG);
 412         for (i = 0; i < XCHAL_NUM_PERF_COUNTERS; ++i) {
 413                 set_er(0, XTENSA_PMU_PMCTRL(i));
 414                 set_er(get_er(XTENSA_PMU_PMSTAT(i)), XTENSA_PMU_PMSTAT(i));
 415         }
 416         return 0;
 417 }
 418
 419 static int __init xtensa_pmu_init(void)
 420 {
 421         int ret;
 422         int irq = irq_create_mapping(NULL, XCHAL_PROFILING_INTERRUPT);
 423
 424         ret = cpuhp_setup_state(CPUHP_AP_PERF_XTENSA_STARTING,
 425                                 "perf/xtensa:starting", xtensa_pmu_setup,
 426                                 NULL);
 427         if (ret) {
 428                 pr_err("xtensa_pmu: failed to register CPU-hotplug.\n");
 429                 return ret;
 430         }
 431 #if XTENSA_FAKE_NMI
 432         enable_irq(irq);
 433 #else
 434         ret = request_irq(irq, xtensa_pmu_irq_handler, IRQF_PERCPU,
 435                           "pmu", NULL);
 436         if (ret < 0)
 437                 return ret;
 438 #endif
 439
 440         ret = perf_pmu_register(&xtensa_pmu, "cpu", PERF_TYPE_RAW);
 441         if (ret)
 442                 free_irq(irq, NULL);
 443
 444         return ret;
 445 }
 446 early_initcall(xtensa_pmu_init);