drivers/perf/arm_spe_pmu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Perf support for the Statistical Profiling Extension, introduced as
   4  * part of ARMv8.2.
   5  *
   6  * Copyright (C) 2016 ARM Limited
   7  *
   8  * Author: Will Deacon <will.deacon@arm.com>
   9  */
  10
  11 #define PMUNAME                                 "arm_spe"
  12 #define DRVNAME                                 PMUNAME "_pmu"
  13 #define pr_fmt(fmt)                             DRVNAME ": " fmt
  14
  15 #include <linux/bitops.h>
  16 #include <linux/bug.h>
  17 #include <linux/capability.h>
  18 #include <linux/cpuhotplug.h>
  19 #include <linux/cpumask.h>
  20 #include <linux/device.h>
  21 #include <linux/errno.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/irq.h>
  24 #include <linux/kernel.h>
  25 #include <linux/list.h>
  26 #include <linux/module.h>
  27 #include <linux/of_address.h>
  28 #include <linux/of_device.h>
  29 #include <linux/perf_event.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/printk.h>
  32 #include <linux/slab.h>
  33 #include <linux/smp.h>
  34 #include <linux/vmalloc.h>
  35
  36 #include <asm/barrier.h>
  37 #include <asm/cpufeature.h>
  38 #include <asm/mmu.h>
  39 #include <asm/sysreg.h>
  40
  41 #define ARM_SPE_BUF_PAD_BYTE                    0
  42
  43 struct arm_spe_pmu_buf {
  44         int                                     nr_pages;
  45         bool                                    snapshot;
  46         void                                    *base;
  47 };
  48
  49 struct arm_spe_pmu {
  50         struct pmu                              pmu;
  51         struct platform_device                  *pdev;
  52         cpumask_t                               supported_cpus;
  53         struct hlist_node                       hotplug_node;
  54
  55         int                                     irq; /* PPI */
  56
  57         u16                                     min_period;
  58         u16                                     counter_sz;
  59
  60 #define SPE_PMU_FEAT_FILT_EVT                   (1UL << 0)
  61 #define SPE_PMU_FEAT_FILT_TYP                   (1UL << 1)
  62 #define SPE_PMU_FEAT_FILT_LAT                   (1UL << 2)
  63 #define SPE_PMU_FEAT_ARCH_INST                  (1UL << 3)
  64 #define SPE_PMU_FEAT_LDS                        (1UL << 4)
  65 #define SPE_PMU_FEAT_ERND                       (1UL << 5)
  66 #define SPE_PMU_FEAT_DEV_PROBED                 (1UL << 63)
  67         u64                                     features;
  68
  69         u16                                     max_record_sz;
  70         u16                                     align;
  71         struct perf_output_handle __percpu      *handle;
  72 };
  73
  74 #define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))
  75
  76 /* Convert a free-running index from perf into an SPE buffer offset */
  77 #define PERF_IDX2OFF(idx, buf)  ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
  78
  79 /* Keep track of our dynamic hotplug state */
  80 static enum cpuhp_state arm_spe_pmu_online;
  81
  82 enum arm_spe_pmu_buf_fault_action {
  83         SPE_PMU_BUF_FAULT_ACT_SPURIOUS,
  84         SPE_PMU_BUF_FAULT_ACT_FATAL,
  85         SPE_PMU_BUF_FAULT_ACT_OK,
  86 };
  87
  88 /* This sysfs gunk was really good fun to write. */
  89 enum arm_spe_pmu_capabilities {
  90         SPE_PMU_CAP_ARCH_INST = 0,
  91         SPE_PMU_CAP_ERND,
  92         SPE_PMU_CAP_FEAT_MAX,
  93         SPE_PMU_CAP_CNT_SZ = SPE_PMU_CAP_FEAT_MAX,
  94         SPE_PMU_CAP_MIN_IVAL,
  95 };
  96
  97 static int arm_spe_pmu_feat_caps[SPE_PMU_CAP_FEAT_MAX] = {
  98         [SPE_PMU_CAP_ARCH_INST] = SPE_PMU_FEAT_ARCH_INST,
  99         [SPE_PMU_CAP_ERND]      = SPE_PMU_FEAT_ERND,
 100 };
 101
 102 static u32 arm_spe_pmu_cap_get(struct arm_spe_pmu *spe_pmu, int cap)
 103 {
 104         if (cap < SPE_PMU_CAP_FEAT_MAX)
 105                 return !!(spe_pmu->features & arm_spe_pmu_feat_caps[cap]);
 106
 107         switch (cap) {
 108         case SPE_PMU_CAP_CNT_SZ:
 109                 return spe_pmu->counter_sz;
 110         case SPE_PMU_CAP_MIN_IVAL:
 111                 return spe_pmu->min_period;
 112         default:
 113                 WARN(1, "unknown cap %d\n", cap);
 114         }
 115
 116         return 0;
 117 }
 118
 119 static ssize_t arm_spe_pmu_cap_show(struct device *dev,
 120                                     struct device_attribute *attr,
 121                                     char *buf)
 122 {
 123         struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
 124         struct dev_ext_attribute *ea =
 125                 container_of(attr, struct dev_ext_attribute, attr);
 126         int cap = (long)ea->var;
 127
 128         return snprintf(buf, PAGE_SIZE, "%u\n",
 129                 arm_spe_pmu_cap_get(spe_pmu, cap));
 130 }
 131
 132 #define SPE_EXT_ATTR_ENTRY(_name, _func, _var)                          \
 133         &((struct dev_ext_attribute[]) {                                \
 134                 { __ATTR(_name, S_IRUGO, _func, NULL), (void *)_var }   \
 135         })[0].attr.attr
 136
 137 #define SPE_CAP_EXT_ATTR_ENTRY(_name, _var)                             \
 138         SPE_EXT_ATTR_ENTRY(_name, arm_spe_pmu_cap_show, _var)
 139
 140 static struct attribute *arm_spe_pmu_cap_attr[] = {
 141         SPE_CAP_EXT_ATTR_ENTRY(arch_inst, SPE_PMU_CAP_ARCH_INST),
 142         SPE_CAP_EXT_ATTR_ENTRY(ernd, SPE_PMU_CAP_ERND),
 143         SPE_CAP_EXT_ATTR_ENTRY(count_size, SPE_PMU_CAP_CNT_SZ),
 144         SPE_CAP_EXT_ATTR_ENTRY(min_interval, SPE_PMU_CAP_MIN_IVAL),
 145         NULL,
 146 };
 147
 148 static struct attribute_group arm_spe_pmu_cap_group = {
 149         .name   = "caps",
 150         .attrs  = arm_spe_pmu_cap_attr,
 151 };
 152
 153 /* User ABI */
 154 #define ATTR_CFG_FLD_ts_enable_CFG              config  /* PMSCR_EL1.TS */
 155 #define ATTR_CFG_FLD_ts_enable_LO               0
 156 #define ATTR_CFG_FLD_ts_enable_HI               0
 157 #define ATTR_CFG_FLD_pa_enable_CFG              config  /* PMSCR_EL1.PA */
 158 #define ATTR_CFG_FLD_pa_enable_LO               1
 159 #define ATTR_CFG_FLD_pa_enable_HI               1
 160 #define ATTR_CFG_FLD_pct_enable_CFG             config  /* PMSCR_EL1.PCT */
 161 #define ATTR_CFG_FLD_pct_enable_LO              2
 162 #define ATTR_CFG_FLD_pct_enable_HI              2
 163 #define ATTR_CFG_FLD_jitter_CFG                 config  /* PMSIRR_EL1.RND */
 164 #define ATTR_CFG_FLD_jitter_LO                  16
 165 #define ATTR_CFG_FLD_jitter_HI                  16
 166 #define ATTR_CFG_FLD_branch_filter_CFG          config  /* PMSFCR_EL1.B */
 167 #define ATTR_CFG_FLD_branch_filter_LO           32
 168 #define ATTR_CFG_FLD_branch_filter_HI           32
 169 #define ATTR_CFG_FLD_load_filter_CFG            config  /* PMSFCR_EL1.LD */
 170 #define ATTR_CFG_FLD_load_filter_LO             33
 171 #define ATTR_CFG_FLD_load_filter_HI             33
 172 #define ATTR_CFG_FLD_store_filter_CFG           config  /* PMSFCR_EL1.ST */
 173 #define ATTR_CFG_FLD_store_filter_LO            34
 174 #define ATTR_CFG_FLD_store_filter_HI            34
 175
 176 #define ATTR_CFG_FLD_event_filter_CFG           config1 /* PMSEVFR_EL1 */
 177 #define ATTR_CFG_FLD_event_filter_LO            0
 178 #define ATTR_CFG_FLD_event_filter_HI            63
 179
 180 #define ATTR_CFG_FLD_min_latency_CFG            config2 /* PMSLATFR_EL1.MINLAT */
 181 #define ATTR_CFG_FLD_min_latency_LO             0
 182 #define ATTR_CFG_FLD_min_latency_HI             11
 183
 184 /* Why does everything I do descend into this? */
 185 #define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi)                              \
 186         (lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi
 187
 188 #define _GEN_PMU_FORMAT_ATTR(cfg, lo, hi)                               \
 189         __GEN_PMU_FORMAT_ATTR(cfg, lo, hi)
 190
 191 #define GEN_PMU_FORMAT_ATTR(name)                                       \
 192         PMU_FORMAT_ATTR(name,                                           \
 193         _GEN_PMU_FORMAT_ATTR(ATTR_CFG_FLD_##name##_CFG,                 \
 194                              ATTR_CFG_FLD_##name##_LO,                  \
 195                              ATTR_CFG_FLD_##name##_HI))
 196
 197 #define _ATTR_CFG_GET_FLD(attr, cfg, lo, hi)                            \
 198         ((((attr)->cfg) >> lo) & GENMASK(hi - lo, 0))
 199
 200 #define ATTR_CFG_GET_FLD(attr, name)                                    \
 201         _ATTR_CFG_GET_FLD(attr,                                         \
 202                           ATTR_CFG_FLD_##name##_CFG,                    \
 203                           ATTR_CFG_FLD_##name##_LO,                     \
 204                           ATTR_CFG_FLD_##name##_HI)
 205
 206 GEN_PMU_FORMAT_ATTR(ts_enable);
 207 GEN_PMU_FORMAT_ATTR(pa_enable);
 208 GEN_PMU_FORMAT_ATTR(pct_enable);
 209 GEN_PMU_FORMAT_ATTR(jitter);
 210 GEN_PMU_FORMAT_ATTR(branch_filter);
 211 GEN_PMU_FORMAT_ATTR(load_filter);
 212 GEN_PMU_FORMAT_ATTR(store_filter);
 213 GEN_PMU_FORMAT_ATTR(event_filter);
 214 GEN_PMU_FORMAT_ATTR(min_latency);
 215
 216 static struct attribute *arm_spe_pmu_formats_attr[] = {
 217         &format_attr_ts_enable.attr,
 218         &format_attr_pa_enable.attr,
 219         &format_attr_pct_enable.attr,
 220         &format_attr_jitter.attr,
 221         &format_attr_branch_filter.attr,
 222         &format_attr_load_filter.attr,
 223         &format_attr_store_filter.attr,
 224         &format_attr_event_filter.attr,
 225         &format_attr_min_latency.attr,
 226         NULL,
 227 };
 228
 229 static struct attribute_group arm_spe_pmu_format_group = {
 230         .name   = "format",
 231         .attrs  = arm_spe_pmu_formats_attr,
 232 };
 233
 234 static ssize_t arm_spe_pmu_get_attr_cpumask(struct device *dev,
 235                                             struct device_attribute *attr,
 236                                             char *buf)
 237 {
 238         struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
 239
 240         return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
 241 }
 242 static DEVICE_ATTR(cpumask, S_IRUGO, arm_spe_pmu_get_attr_cpumask, NULL);
 243
 244 static struct attribute *arm_spe_pmu_attrs[] = {
 245         &dev_attr_cpumask.attr,
 246         NULL,
 247 };
 248
 249 static struct attribute_group arm_spe_pmu_group = {
 250         .attrs  = arm_spe_pmu_attrs,
 251 };
 252
 253 static const struct attribute_group *arm_spe_pmu_attr_groups[] = {
 254         &arm_spe_pmu_group,
 255         &arm_spe_pmu_cap_group,
 256         &arm_spe_pmu_format_group,
 257         NULL,
 258 };
 259
 260 /* Convert between user ABI and register values */
 261 static u64 arm_spe_event_to_pmscr(struct perf_event *event)
 262 {
 263         struct perf_event_attr *attr = &event->attr;
 264         u64 reg = 0;
 265
 266         reg |= ATTR_CFG_GET_FLD(attr, ts_enable) << SYS_PMSCR_EL1_TS_SHIFT;
 267         reg |= ATTR_CFG_GET_FLD(attr, pa_enable) << SYS_PMSCR_EL1_PA_SHIFT;
 268         reg |= ATTR_CFG_GET_FLD(attr, pct_enable) << SYS_PMSCR_EL1_PCT_SHIFT;
 269
 270         if (!attr->exclude_user)
 271                 reg |= BIT(SYS_PMSCR_EL1_E0SPE_SHIFT);
 272
 273         if (!attr->exclude_kernel)
 274                 reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT);
 275
 276         if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && capable(CAP_SYS_ADMIN))
 277                 reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT);
 278
 279         return reg;
 280 }
 281
 282 static void arm_spe_event_sanitise_period(struct perf_event *event)
 283 {
 284         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 285         u64 period = event->hw.sample_period;
 286         u64 max_period = SYS_PMSIRR_EL1_INTERVAL_MASK
 287                          << SYS_PMSIRR_EL1_INTERVAL_SHIFT;
 288
 289         if (period < spe_pmu->min_period)
 290                 period = spe_pmu->min_period;
 291         else if (period > max_period)
 292                 period = max_period;
 293         else
 294                 period &= max_period;
 295
 296         event->hw.sample_period = period;
 297 }
 298
 299 static u64 arm_spe_event_to_pmsirr(struct perf_event *event)
 300 {
 301         struct perf_event_attr *attr = &event->attr;
 302         u64 reg = 0;
 303
 304         arm_spe_event_sanitise_period(event);
 305
 306         reg |= ATTR_CFG_GET_FLD(attr, jitter) << SYS_PMSIRR_EL1_RND_SHIFT;
 307         reg |= event->hw.sample_period;
 308
 309         return reg;
 310 }
 311
 312 static u64 arm_spe_event_to_pmsfcr(struct perf_event *event)
 313 {
 314         struct perf_event_attr *attr = &event->attr;
 315         u64 reg = 0;
 316
 317         reg |= ATTR_CFG_GET_FLD(attr, load_filter) << SYS_PMSFCR_EL1_LD_SHIFT;
 318         reg |= ATTR_CFG_GET_FLD(attr, store_filter) << SYS_PMSFCR_EL1_ST_SHIFT;
 319         reg |= ATTR_CFG_GET_FLD(attr, branch_filter) << SYS_PMSFCR_EL1_B_SHIFT;
 320
 321         if (reg)
 322                 reg |= BIT(SYS_PMSFCR_EL1_FT_SHIFT);
 323
 324         if (ATTR_CFG_GET_FLD(attr, event_filter))
 325                 reg |= BIT(SYS_PMSFCR_EL1_FE_SHIFT);
 326
 327         if (ATTR_CFG_GET_FLD(attr, min_latency))
 328                 reg |= BIT(SYS_PMSFCR_EL1_FL_SHIFT);
 329
 330         return reg;
 331 }
 332
 333 static u64 arm_spe_event_to_pmsevfr(struct perf_event *event)
 334 {
 335         struct perf_event_attr *attr = &event->attr;
 336         return ATTR_CFG_GET_FLD(attr, event_filter);
 337 }
 338
 339 static u64 arm_spe_event_to_pmslatfr(struct perf_event *event)
 340 {
 341         struct perf_event_attr *attr = &event->attr;
 342         return ATTR_CFG_GET_FLD(attr, min_latency)
 343                << SYS_PMSLATFR_EL1_MINLAT_SHIFT;
 344 }
 345
 346 static void arm_spe_pmu_pad_buf(struct perf_output_handle *handle, int len)
 347 {
 348         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 349         u64 head = PERF_IDX2OFF(handle->head, buf);
 350
 351         memset(buf->base + head, ARM_SPE_BUF_PAD_BYTE, len);
 352         if (!buf->snapshot)
 353                 perf_aux_output_skip(handle, len);
 354 }
 355
 356 static u64 arm_spe_pmu_next_snapshot_off(struct perf_output_handle *handle)
 357 {
 358         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 359         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 360         u64 head = PERF_IDX2OFF(handle->head, buf);
 361         u64 limit = buf->nr_pages * PAGE_SIZE;
 362
 363         /*
 364          * The trace format isn't parseable in reverse, so clamp
 365          * the limit to half of the buffer size in snapshot mode
 366          * so that the worst case is half a buffer of records, as
 367          * opposed to a single record.
 368          */
 369         if (head < limit >> 1)
 370                 limit >>= 1;
 371
 372         /*
 373          * If we're within max_record_sz of the limit, we must
 374          * pad, move the head index and recompute the limit.
 375          */
 376         if (limit - head < spe_pmu->max_record_sz) {
 377                 arm_spe_pmu_pad_buf(handle, limit - head);
 378                 handle->head = PERF_IDX2OFF(limit, buf);
 379                 limit = ((buf->nr_pages * PAGE_SIZE) >> 1) + handle->head;
 380         }
 381
 382         return limit;
 383 }
 384
 385 static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle)
 386 {
 387         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 388         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 389         const u64 bufsize = buf->nr_pages * PAGE_SIZE;
 390         u64 limit = bufsize;
 391         u64 head, tail, wakeup;
 392
 393         /*
 394          * The head can be misaligned for two reasons:
 395          *
 396          * 1. The hardware left PMBPTR pointing to the first byte after
 397          *    a record when generating a buffer management event.
 398          *
 399          * 2. We used perf_aux_output_skip to consume handle->size bytes
 400          *    and CIRC_SPACE was used to compute the size, which always
 401          *    leaves one entry free.
 402          *
 403          * Deal with this by padding to the next alignment boundary and
 404          * moving the head index. If we run out of buffer space, we'll
 405          * reduce handle->size to zero and end up reporting truncation.
 406          */
 407         head = PERF_IDX2OFF(handle->head, buf);
 408         if (!IS_ALIGNED(head, spe_pmu->align)) {
 409                 unsigned long delta = roundup(head, spe_pmu->align) - head;
 410
 411                 delta = min(delta, handle->size);
 412                 arm_spe_pmu_pad_buf(handle, delta);
 413                 head = PERF_IDX2OFF(handle->head, buf);
 414         }
 415
 416         /* If we've run out of free space, then nothing more to do */
 417         if (!handle->size)
 418                 goto no_space;
 419
 420         /* Compute the tail and wakeup indices now that we've aligned head */
 421         tail = PERF_IDX2OFF(handle->head + handle->size, buf);
 422         wakeup = PERF_IDX2OFF(handle->wakeup, buf);
 423
 424         /*
 425          * Avoid clobbering unconsumed data. We know we have space, so
 426          * if we see head == tail we know that the buffer is empty. If
 427          * head > tail, then there's nothing to clobber prior to
 428          * wrapping.
 429          */
 430         if (head < tail)
 431                 limit = round_down(tail, PAGE_SIZE);
 432
 433         /*
 434          * Wakeup may be arbitrarily far into the future. If it's not in
 435          * the current generation, either we'll wrap before hitting it,
 436          * or it's in the past and has been handled already.
 437          *
 438          * If there's a wakeup before we wrap, arrange to be woken up by
 439          * the page boundary following it. Keep the tail boundary if
 440          * that's lower.
 441          */
 442         if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
 443                 limit = min(limit, round_up(wakeup, PAGE_SIZE));
 444
 445         if (limit > head)
 446                 return limit;
 447
 448         arm_spe_pmu_pad_buf(handle, handle->size);
 449 no_space:
 450         perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
 451         perf_aux_output_end(handle, 0);
 452         return 0;
 453 }
 454
 455 static u64 arm_spe_pmu_next_off(struct perf_output_handle *handle)
 456 {
 457         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 458         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 459         u64 limit = __arm_spe_pmu_next_off(handle);
 460         u64 head = PERF_IDX2OFF(handle->head, buf);
 461
 462         /*
 463          * If the head has come too close to the end of the buffer,
 464          * then pad to the end and recompute the limit.
 465          */
 466         if (limit && (limit - head < spe_pmu->max_record_sz)) {
 467                 arm_spe_pmu_pad_buf(handle, limit - head);
 468                 limit = __arm_spe_pmu_next_off(handle);
 469         }
 470
 471         return limit;
 472 }
 473
 474 static void arm_spe_perf_aux_output_begin(struct perf_output_handle *handle,
 475                                           struct perf_event *event)
 476 {
 477         u64 base, limit;
 478         struct arm_spe_pmu_buf *buf;
 479
 480         /* Start a new aux session */
 481         buf = perf_aux_output_begin(handle, event);
 482         if (!buf) {
 483                 event->hw.state |= PERF_HES_STOPPED;
 484                 /*
 485                  * We still need to clear the limit pointer, since the
 486                  * profiler might only be disabled by virtue of a fault.
 487                  */
 488                 limit = 0;
 489                 goto out_write_limit;
 490         }
 491
 492         limit = buf->snapshot ? arm_spe_pmu_next_snapshot_off(handle)
 493                               : arm_spe_pmu_next_off(handle);
 494         if (limit)
 495                 limit |= BIT(SYS_PMBLIMITR_EL1_E_SHIFT);
 496
 497         limit += (u64)buf->base;
 498         base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf);
 499         write_sysreg_s(base, SYS_PMBPTR_EL1);
 500
 501 out_write_limit:
 502         write_sysreg_s(limit, SYS_PMBLIMITR_EL1);
 503 }
 504
 505 static void arm_spe_perf_aux_output_end(struct perf_output_handle *handle)
 506 {
 507         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 508         u64 offset, size;
 509
 510         offset = read_sysreg_s(SYS_PMBPTR_EL1) - (u64)buf->base;
 511         size = offset - PERF_IDX2OFF(handle->head, buf);
 512
 513         if (buf->snapshot)
 514                 handle->head = offset;
 515
 516         perf_aux_output_end(handle, size);
 517 }
 518
 519 static void arm_spe_pmu_disable_and_drain_local(void)
 520 {
 521         /* Disable profiling at EL0 and EL1 */
 522         write_sysreg_s(0, SYS_PMSCR_EL1);
 523         isb();
 524
 525         /* Drain any buffered data */
 526         psb_csync();
 527         dsb(nsh);
 528
 529         /* Disable the profiling buffer */
 530         write_sysreg_s(0, SYS_PMBLIMITR_EL1);
 531         isb();
 532 }
 533
 534 /* IRQ handling */
 535 static enum arm_spe_pmu_buf_fault_action
 536 arm_spe_pmu_buf_get_fault_act(struct perf_output_handle *handle)
 537 {
 538         const char *err_str;
 539         u64 pmbsr;
 540         enum arm_spe_pmu_buf_fault_action ret;
 541
 542         /*
 543          * Ensure new profiling data is visible to the CPU and any external
 544          * aborts have been resolved.
 545          */
 546         psb_csync();
 547         dsb(nsh);
 548
 549         /* Ensure hardware updates to PMBPTR_EL1 are visible */
 550         isb();
 551
 552         /* Service required? */
 553         pmbsr = read_sysreg_s(SYS_PMBSR_EL1);
 554         if (!(pmbsr & BIT(SYS_PMBSR_EL1_S_SHIFT)))
 555                 return SPE_PMU_BUF_FAULT_ACT_SPURIOUS;
 556
 557         /*
 558          * If we've lost data, disable profiling and also set the PARTIAL
 559          * flag to indicate that the last record is corrupted.
 560          */
 561         if (pmbsr & BIT(SYS_PMBSR_EL1_DL_SHIFT))
 562                 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED |
 563                                              PERF_AUX_FLAG_PARTIAL);
 564
 565         /* Report collisions to userspace so that it can up the period */
 566         if (pmbsr & BIT(SYS_PMBSR_EL1_COLL_SHIFT))
 567                 perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
 568
 569         /* We only expect buffer management events */
 570         switch (pmbsr & (SYS_PMBSR_EL1_EC_MASK << SYS_PMBSR_EL1_EC_SHIFT)) {
 571         case SYS_PMBSR_EL1_EC_BUF:
 572                 /* Handled below */
 573                 break;
 574         case SYS_PMBSR_EL1_EC_FAULT_S1:
 575         case SYS_PMBSR_EL1_EC_FAULT_S2:
 576                 err_str = "Unexpected buffer fault";
 577                 goto out_err;
 578         default:
 579                 err_str = "Unknown error code";
 580                 goto out_err;
 581         }
 582
 583         /* Buffer management event */
 584         switch (pmbsr &
 585                 (SYS_PMBSR_EL1_BUF_BSC_MASK << SYS_PMBSR_EL1_BUF_BSC_SHIFT)) {
 586         case SYS_PMBSR_EL1_BUF_BSC_FULL:
 587                 ret = SPE_PMU_BUF_FAULT_ACT_OK;
 588                 goto out_stop;
 589         default:
 590                 err_str = "Unknown buffer status code";
 591         }
 592
 593 out_err:
 594         pr_err_ratelimited("%s on CPU %d [PMBSR=0x%016llx, PMBPTR=0x%016llx, PMBLIMITR=0x%016llx]\n",
 595                            err_str, smp_processor_id(), pmbsr,
 596                            read_sysreg_s(SYS_PMBPTR_EL1),
 597                            read_sysreg_s(SYS_PMBLIMITR_EL1));
 598         ret = SPE_PMU_BUF_FAULT_ACT_FATAL;
 599
 600 out_stop:
 601         arm_spe_perf_aux_output_end(handle);
 602         return ret;
 603 }
 604
 605 static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev)
 606 {
 607         struct perf_output_handle *handle = dev;
 608         struct perf_event *event = handle->event;
 609         enum arm_spe_pmu_buf_fault_action act;
 610
 611         if (!perf_get_aux(handle))
 612                 return IRQ_NONE;
 613
 614         act = arm_spe_pmu_buf_get_fault_act(handle);
 615         if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
 616                 return IRQ_NONE;
 617
 618         /*
 619          * Ensure perf callbacks have completed, which may disable the
 620          * profiling buffer in response to a TRUNCATION flag.
 621          */
 622         irq_work_run();
 623
 624         switch (act) {
 625         case SPE_PMU_BUF_FAULT_ACT_FATAL:
 626                 /*
 627                  * If a fatal exception occurred then leaving the profiling
 628                  * buffer enabled is a recipe waiting to happen. Since
 629                  * fatal faults don't always imply truncation, make sure
 630                  * that the profiling buffer is disabled explicitly before
 631                  * clearing the syndrome register.
 632                  */
 633                 arm_spe_pmu_disable_and_drain_local();
 634                 break;
 635         case SPE_PMU_BUF_FAULT_ACT_OK:
 636                 /*
 637                  * We handled the fault (the buffer was full), so resume
 638                  * profiling as long as we didn't detect truncation.
 639                  * PMBPTR might be misaligned, but we'll burn that bridge
 640                  * when we get to it.
 641                  */
 642                 if (!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)) {
 643                         arm_spe_perf_aux_output_begin(handle, event);
 644                         isb();
 645                 }
 646                 break;
 647         case SPE_PMU_BUF_FAULT_ACT_SPURIOUS:
 648                 /* We've seen you before, but GCC has the memory of a sieve. */
 649                 break;
 650         }
 651
 652         /* The buffer pointers are now sane, so resume profiling. */
 653         write_sysreg_s(0, SYS_PMBSR_EL1);
 654         return IRQ_HANDLED;
 655 }
 656
 657 /* Perf callbacks */
 658 static int arm_spe_pmu_event_init(struct perf_event *event)
 659 {
 660         u64 reg;
 661         struct perf_event_attr *attr = &event->attr;
 662         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 663
 664         /* This is, of course, deeply driver-specific */
 665         if (attr->type != event->pmu->type)
 666                 return -ENOENT;
 667
 668         if (event->cpu >= 0 &&
 669             !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus))
 670                 return -ENOENT;
 671
 672         if (arm_spe_event_to_pmsevfr(event) & SYS_PMSEVFR_EL1_RES0)
 673                 return -EOPNOTSUPP;
 674
 675         if (attr->exclude_idle)
 676                 return -EOPNOTSUPP;
 677
 678         /*
 679          * Feedback-directed frequency throttling doesn't work when we
 680          * have a buffer of samples. We'd need to manually count the
 681          * samples in the buffer when it fills up and adjust the event
 682          * count to reflect that. Instead, just force the user to specify
 683          * a sample period.
 684          */
 685         if (attr->freq)
 686                 return -EINVAL;
 687
 688         reg = arm_spe_event_to_pmsfcr(event);
 689         if ((reg & BIT(SYS_PMSFCR_EL1_FE_SHIFT)) &&
 690             !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT))
 691                 return -EOPNOTSUPP;
 692
 693         if ((reg & BIT(SYS_PMSFCR_EL1_FT_SHIFT)) &&
 694             !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP))
 695                 return -EOPNOTSUPP;
 696
 697         if ((reg & BIT(SYS_PMSFCR_EL1_FL_SHIFT)) &&
 698             !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
 699                 return -EOPNOTSUPP;
 700
 701         reg = arm_spe_event_to_pmscr(event);
 702         if (!capable(CAP_SYS_ADMIN) &&
 703             (reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) |
 704                     BIT(SYS_PMSCR_EL1_CX_SHIFT) |
 705                     BIT(SYS_PMSCR_EL1_PCT_SHIFT))))
 706                 return -EACCES;
 707
 708         return 0;
 709 }
 710
 711 static void arm_spe_pmu_start(struct perf_event *event, int flags)
 712 {
 713         u64 reg;
 714         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 715         struct hw_perf_event *hwc = &event->hw;
 716         struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
 717
 718         hwc->state = 0;
 719         arm_spe_perf_aux_output_begin(handle, event);
 720         if (hwc->state)
 721                 return;
 722
 723         reg = arm_spe_event_to_pmsfcr(event);
 724         write_sysreg_s(reg, SYS_PMSFCR_EL1);
 725
 726         reg = arm_spe_event_to_pmsevfr(event);
 727         write_sysreg_s(reg, SYS_PMSEVFR_EL1);
 728
 729         reg = arm_spe_event_to_pmslatfr(event);
 730         write_sysreg_s(reg, SYS_PMSLATFR_EL1);
 731
 732         if (flags & PERF_EF_RELOAD) {
 733                 reg = arm_spe_event_to_pmsirr(event);
 734                 write_sysreg_s(reg, SYS_PMSIRR_EL1);
 735                 isb();
 736                 reg = local64_read(&hwc->period_left);
 737                 write_sysreg_s(reg, SYS_PMSICR_EL1);
 738         }
 739
 740         reg = arm_spe_event_to_pmscr(event);
 741         isb();
 742         write_sysreg_s(reg, SYS_PMSCR_EL1);
 743 }
 744
 745 static void arm_spe_pmu_stop(struct perf_event *event, int flags)
 746 {
 747         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 748         struct hw_perf_event *hwc = &event->hw;
 749         struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
 750
 751         /* If we're already stopped, then nothing to do */
 752         if (hwc->state & PERF_HES_STOPPED)
 753                 return;
 754
 755         /* Stop all trace generation */
 756         arm_spe_pmu_disable_and_drain_local();
 757
 758         if (flags & PERF_EF_UPDATE) {
 759                 /*
 760                  * If there's a fault pending then ensure we contain it
 761                  * to this buffer, since we might be on the context-switch
 762                  * path.
 763                  */
 764                 if (perf_get_aux(handle)) {
 765                         enum arm_spe_pmu_buf_fault_action act;
 766
 767                         act = arm_spe_pmu_buf_get_fault_act(handle);
 768                         if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
 769                                 arm_spe_perf_aux_output_end(handle);
 770                         else
 771                                 write_sysreg_s(0, SYS_PMBSR_EL1);
 772                 }
 773
 774                 /*
 775                  * This may also contain ECOUNT, but nobody else should
 776                  * be looking at period_left, since we forbid frequency
 777                  * based sampling.
 778                  */
 779                 local64_set(&hwc->period_left, read_sysreg_s(SYS_PMSICR_EL1));
 780                 hwc->state |= PERF_HES_UPTODATE;
 781         }
 782
 783         hwc->state |= PERF_HES_STOPPED;
 784 }
 785
 786 static int arm_spe_pmu_add(struct perf_event *event, int flags)
 787 {
 788         int ret = 0;
 789         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 790         struct hw_perf_event *hwc = &event->hw;
 791         int cpu = event->cpu == -1 ? smp_processor_id() : event->cpu;
 792
 793         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
 794                 return -ENOENT;
 795
 796         hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
 797
 798         if (flags & PERF_EF_START) {
 799                 arm_spe_pmu_start(event, PERF_EF_RELOAD);
 800                 if (hwc->state & PERF_HES_STOPPED)
 801                         ret = -EINVAL;
 802         }
 803
 804         return ret;
 805 }
 806
 807 static void arm_spe_pmu_del(struct perf_event *event, int flags)
 808 {
 809         arm_spe_pmu_stop(event, PERF_EF_UPDATE);
 810 }
 811
 812 static void arm_spe_pmu_read(struct perf_event *event)
 813 {
 814 }
 815
 816 static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
 817                                    int nr_pages, bool snapshot)
 818 {
 819         int i, cpu = event->cpu;
 820         struct page **pglist;
 821         struct arm_spe_pmu_buf *buf;
 822
 823         /* We need at least two pages for this to work. */
 824         if (nr_pages < 2)
 825                 return NULL;
 826
 827         /*
 828          * We require an even number of pages for snapshot mode, so that
 829          * we can effectively treat the buffer as consisting of two equal
 830          * parts and give userspace a fighting chance of getting some
 831          * useful data out of it.
 832          */
 833         if (!nr_pages || (snapshot && (nr_pages & 1)))
 834                 return NULL;
 835
 836         if (cpu == -1)
 837                 cpu = raw_smp_processor_id();
 838
 839         buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, cpu_to_node(cpu));
 840         if (!buf)
 841                 return NULL;
 842
 843         pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
 844         if (!pglist)
 845                 goto out_free_buf;
 846
 847         for (i = 0; i < nr_pages; ++i)
 848                 pglist[i] = virt_to_page(pages[i]);
 849
 850         buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
 851         if (!buf->base)
 852                 goto out_free_pglist;
 853
 854         buf->nr_pages   = nr_pages;
 855         buf->snapshot   = snapshot;
 856
 857         kfree(pglist);
 858         return buf;
 859
 860 out_free_pglist:
 861         kfree(pglist);
 862 out_free_buf:
 863         kfree(buf);
 864         return NULL;
 865 }
 866
 867 static void arm_spe_pmu_free_aux(void *aux)
 868 {
 869         struct arm_spe_pmu_buf *buf = aux;
 870
 871         vunmap(buf->base);
 872         kfree(buf);
 873 }
 874
 875 /* Initialisation and teardown functions */
 876 static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
 877 {
 878         static atomic_t pmu_idx = ATOMIC_INIT(-1);
 879
 880         int idx;
 881         char *name;
 882         struct device *dev = &spe_pmu->pdev->dev;
 883
 884         spe_pmu->pmu = (struct pmu) {
 885                 .module = THIS_MODULE,
 886                 .capabilities   = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
 887                 .attr_groups    = arm_spe_pmu_attr_groups,
 888                 /*
 889                  * We hitch a ride on the software context here, so that
 890                  * we can support per-task profiling (which is not possible
 891                  * with the invalid context as it doesn't get sched callbacks).
 892                  * This requires that userspace either uses a dummy event for
 893                  * perf_event_open, since the aux buffer is not setup until
 894                  * a subsequent mmap, or creates the profiling event in a
 895                  * disabled state and explicitly PERF_EVENT_IOC_ENABLEs it
 896                  * once the buffer has been created.
 897                  */
 898                 .task_ctx_nr    = perf_sw_context,
 899                 .event_init     = arm_spe_pmu_event_init,
 900                 .add            = arm_spe_pmu_add,
 901                 .del            = arm_spe_pmu_del,
 902                 .start          = arm_spe_pmu_start,
 903                 .stop           = arm_spe_pmu_stop,
 904                 .read           = arm_spe_pmu_read,
 905                 .setup_aux      = arm_spe_pmu_setup_aux,
 906                 .free_aux       = arm_spe_pmu_free_aux,
 907         };
 908
 909         idx = atomic_inc_return(&pmu_idx);
 910         name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx);
 911         if (!name) {
 912                 dev_err(dev, "failed to allocate name for pmu %d\n", idx);
 913                 return -ENOMEM;
 914         }
 915
 916         return perf_pmu_register(&spe_pmu->pmu, name, -1);
 917 }
 918
 919 static void arm_spe_pmu_perf_destroy(struct arm_spe_pmu *spe_pmu)
 920 {
 921         perf_pmu_unregister(&spe_pmu->pmu);
 922 }
 923
 924 static void __arm_spe_pmu_dev_probe(void *info)
 925 {
 926         int fld;
 927         u64 reg;
 928         struct arm_spe_pmu *spe_pmu = info;
 929         struct device *dev = &spe_pmu->pdev->dev;
 930
 931         fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64DFR0_EL1),
 932                                                    ID_AA64DFR0_PMSVER_SHIFT);
 933         if (!fld) {
 934                 dev_err(dev,
 935                         "unsupported ID_AA64DFR0_EL1.PMSVer [%d] on CPU %d\n",
 936                         fld, smp_processor_id());
 937                 return;
 938         }
 939
 940         /* Read PMBIDR first to determine whether or not we have access */
 941         reg = read_sysreg_s(SYS_PMBIDR_EL1);
 942         if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT)) {
 943                 dev_err(dev,
 944                         "profiling buffer owned by higher exception level\n");
 945                 return;
 946         }
 947
 948         /* Minimum alignment. If it's out-of-range, then fail the probe */
 949         fld = reg >> SYS_PMBIDR_EL1_ALIGN_SHIFT & SYS_PMBIDR_EL1_ALIGN_MASK;
 950         spe_pmu->align = 1 << fld;
 951         if (spe_pmu->align > SZ_2K) {
 952                 dev_err(dev, "unsupported PMBIDR.Align [%d] on CPU %d\n",
 953                         fld, smp_processor_id());
 954                 return;
 955         }
 956
 957         /* It's now safe to read PMSIDR and figure out what we've got */
 958         reg = read_sysreg_s(SYS_PMSIDR_EL1);
 959         if (reg & BIT(SYS_PMSIDR_EL1_FE_SHIFT))
 960                 spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT;
 961
 962         if (reg & BIT(SYS_PMSIDR_EL1_FT_SHIFT))
 963                 spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP;
 964
 965         if (reg & BIT(SYS_PMSIDR_EL1_FL_SHIFT))
 966                 spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT;
 967
 968         if (reg & BIT(SYS_PMSIDR_EL1_ARCHINST_SHIFT))
 969                 spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST;
 970
 971         if (reg & BIT(SYS_PMSIDR_EL1_LDS_SHIFT))
 972                 spe_pmu->features |= SPE_PMU_FEAT_LDS;
 973
 974         if (reg & BIT(SYS_PMSIDR_EL1_ERND_SHIFT))
 975                 spe_pmu->features |= SPE_PMU_FEAT_ERND;
 976
 977         /* This field has a spaced out encoding, so just use a look-up */
 978         fld = reg >> SYS_PMSIDR_EL1_INTERVAL_SHIFT & SYS_PMSIDR_EL1_INTERVAL_MASK;
 979         switch (fld) {
 980         case 0:
 981                 spe_pmu->min_period = 256;
 982                 break;
 983         case 2:
 984                 spe_pmu->min_period = 512;
 985                 break;
 986         case 3:
 987                 spe_pmu->min_period = 768;
 988                 break;
 989         case 4:
 990                 spe_pmu->min_period = 1024;
 991                 break;
 992         case 5:
 993                 spe_pmu->min_period = 1536;
 994                 break;
 995         case 6:
 996                 spe_pmu->min_period = 2048;
 997                 break;
 998         case 7:
 999                 spe_pmu->min_period = 3072;
1000                 break;
1001         default:
1002                 dev_warn(dev, "unknown PMSIDR_EL1.Interval [%d]; assuming 8\n",
1003                          fld);
1004                 /* Fallthrough */
1005         case 8:
1006                 spe_pmu->min_period = 4096;
1007         }
1008
1009         /* Maximum record size. If it's out-of-range, then fail the probe */
1010         fld = reg >> SYS_PMSIDR_EL1_MAXSIZE_SHIFT & SYS_PMSIDR_EL1_MAXSIZE_MASK;
1011         spe_pmu->max_record_sz = 1 << fld;
1012         if (spe_pmu->max_record_sz > SZ_2K || spe_pmu->max_record_sz < 16) {
1013                 dev_err(dev, "unsupported PMSIDR_EL1.MaxSize [%d] on CPU %d\n",
1014                         fld, smp_processor_id());
1015                 return;
1016         }
1017
1018         fld = reg >> SYS_PMSIDR_EL1_COUNTSIZE_SHIFT & SYS_PMSIDR_EL1_COUNTSIZE_MASK;
1019         switch (fld) {
1020         default:
1021                 dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n",
1022                          fld);
1023                 /* Fallthrough */
1024         case 2:
1025                 spe_pmu->counter_sz = 12;
1026         }
1027
1028         dev_info(dev,
1029                  "probed for CPUs %*pbl [max_record_sz %u, align %u, features 0x%llx]\n",
1030                  cpumask_pr_args(&spe_pmu->supported_cpus),
1031                  spe_pmu->max_record_sz, spe_pmu->align, spe_pmu->features);
1032
1033         spe_pmu->features |= SPE_PMU_FEAT_DEV_PROBED;
1034         return;
1035 }
1036
1037 static void __arm_spe_pmu_reset_local(void)
1038 {
1039         /*
1040          * This is probably overkill, as we have no idea where we're
1041          * draining any buffered data to...
1042          */
1043         arm_spe_pmu_disable_and_drain_local();
1044
1045         /* Reset the buffer base pointer */
1046         write_sysreg_s(0, SYS_PMBPTR_EL1);
1047         isb();
1048
1049         /* Clear any pending management interrupts */
1050         write_sysreg_s(0, SYS_PMBSR_EL1);
1051         isb();
1052 }
1053
1054 static void __arm_spe_pmu_setup_one(void *info)
1055 {
1056         struct arm_spe_pmu *spe_pmu = info;
1057
1058         __arm_spe_pmu_reset_local();
1059         enable_percpu_irq(spe_pmu->irq, IRQ_TYPE_NONE);
1060 }
1061
1062 static void __arm_spe_pmu_stop_one(void *info)
1063 {
1064         struct arm_spe_pmu *spe_pmu = info;
1065
1066         disable_percpu_irq(spe_pmu->irq);
1067         __arm_spe_pmu_reset_local();
1068 }
1069
1070 static int arm_spe_pmu_cpu_startup(unsigned int cpu, struct hlist_node *node)
1071 {
1072         struct arm_spe_pmu *spe_pmu;
1073
1074         spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1075         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1076                 return 0;
1077
1078         __arm_spe_pmu_setup_one(spe_pmu);
1079         return 0;
1080 }
1081
1082 static int arm_spe_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
1083 {
1084         struct arm_spe_pmu *spe_pmu;
1085
1086         spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1087         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1088                 return 0;
1089
1090         __arm_spe_pmu_stop_one(spe_pmu);
1091         return 0;
1092 }
1093
1094 static int arm_spe_pmu_dev_init(struct arm_spe_pmu *spe_pmu)
1095 {
1096         int ret;
1097         cpumask_t *mask = &spe_pmu->supported_cpus;
1098
1099         /* Make sure we probe the hardware on a relevant CPU */
1100         ret = smp_call_function_any(mask,  __arm_spe_pmu_dev_probe, spe_pmu, 1);
1101         if (ret || !(spe_pmu->features & SPE_PMU_FEAT_DEV_PROBED))
1102                 return -ENXIO;
1103
1104         /* Request our PPIs (note that the IRQ is still disabled) */
1105         ret = request_percpu_irq(spe_pmu->irq, arm_spe_pmu_irq_handler, DRVNAME,
1106                                  spe_pmu->handle);
1107         if (ret)
1108                 return ret;
1109
1110         /*
1111          * Register our hotplug notifier now so we don't miss any events.
1112          * This will enable the IRQ for any supported CPUs that are already
1113          * up.
1114          */
1115         ret = cpuhp_state_add_instance(arm_spe_pmu_online,
1116                                        &spe_pmu->hotplug_node);
1117         if (ret)
1118                 free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1119
1120         return ret;
1121 }
1122
1123 static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu)
1124 {
1125         cpuhp_state_remove_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node);
1126         free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1127 }
1128
1129 /* Driver and device probing */
1130 static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu)
1131 {
1132         struct platform_device *pdev = spe_pmu->pdev;
1133         int irq = platform_get_irq(pdev, 0);
1134
1135         if (irq < 0) {
1136                 dev_err(&pdev->dev, "failed to get IRQ (%d)\n", irq);
1137                 return -ENXIO;
1138         }
1139
1140         if (!irq_is_percpu(irq)) {
1141                 dev_err(&pdev->dev, "expected PPI but got SPI (%d)\n", irq);
1142                 return -EINVAL;
1143         }
1144
1145         if (irq_get_percpu_devid_partition(irq, &spe_pmu->supported_cpus)) {
1146                 dev_err(&pdev->dev, "failed to get PPI partition (%d)\n", irq);
1147                 return -EINVAL;
1148         }
1149
1150         spe_pmu->irq = irq;
1151         return 0;
1152 }
1153
1154 static const struct of_device_id arm_spe_pmu_of_match[] = {
1155         { .compatible = "arm,statistical-profiling-extension-v1", .data = (void *)1 },
1156         { /* Sentinel */ },
1157 };
1158 MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
1159
1160 static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
1161 {
1162         int ret;
1163         struct arm_spe_pmu *spe_pmu;
1164         struct device *dev = &pdev->dev;
1165
1166         /*
1167          * If kernelspace is unmapped when running at EL0, then the SPE
1168          * buffer will fault and prematurely terminate the AUX session.
1169          */
1170         if (arm64_kernel_unmapped_at_el0()) {
1171                 dev_warn_once(dev, "profiling buffer inaccessible. Try passing \"kpti=off\" on the kernel command line\n");
1172                 return -EPERM;
1173         }
1174
1175         spe_pmu = devm_kzalloc(dev, sizeof(*spe_pmu), GFP_KERNEL);
1176         if (!spe_pmu) {
1177                 dev_err(dev, "failed to allocate spe_pmu\n");
1178                 return -ENOMEM;
1179         }
1180
1181         spe_pmu->handle = alloc_percpu(typeof(*spe_pmu->handle));
1182         if (!spe_pmu->handle)
1183                 return -ENOMEM;
1184
1185         spe_pmu->pdev = pdev;
1186         platform_set_drvdata(pdev, spe_pmu);
1187
1188         ret = arm_spe_pmu_irq_probe(spe_pmu);
1189         if (ret)
1190                 goto out_free_handle;
1191
1192         ret = arm_spe_pmu_dev_init(spe_pmu);
1193         if (ret)
1194                 goto out_free_handle;
1195
1196         ret = arm_spe_pmu_perf_init(spe_pmu);
1197         if (ret)
1198                 goto out_teardown_dev;
1199
1200         return 0;
1201
1202 out_teardown_dev:
1203         arm_spe_pmu_dev_teardown(spe_pmu);
1204 out_free_handle:
1205         free_percpu(spe_pmu->handle);
1206         return ret;
1207 }
1208
1209 static int arm_spe_pmu_device_remove(struct platform_device *pdev)
1210 {
1211         struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
1212
1213         arm_spe_pmu_perf_destroy(spe_pmu);
1214         arm_spe_pmu_dev_teardown(spe_pmu);
1215         free_percpu(spe_pmu->handle);
1216         return 0;
1217 }
1218
1219 static struct platform_driver arm_spe_pmu_driver = {
1220         .driver = {
1221                 .name           = DRVNAME,
1222                 .of_match_table = of_match_ptr(arm_spe_pmu_of_match),
1223         },
1224         .probe  = arm_spe_pmu_device_dt_probe,
1225         .remove = arm_spe_pmu_device_remove,
1226 };
1227
1228 static int __init arm_spe_pmu_init(void)
1229 {
1230         int ret;
1231
1232         ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
1233                                       arm_spe_pmu_cpu_startup,
1234                                       arm_spe_pmu_cpu_teardown);
1235         if (ret < 0)
1236                 return ret;
1237         arm_spe_pmu_online = ret;
1238
1239         ret = platform_driver_register(&arm_spe_pmu_driver);
1240         if (ret)
1241                 cpuhp_remove_multi_state(arm_spe_pmu_online);
1242
1243         return ret;
1244 }
1245
1246 static void __exit arm_spe_pmu_exit(void)
1247 {
1248         platform_driver_unregister(&arm_spe_pmu_driver);
1249         cpuhp_remove_multi_state(arm_spe_pmu_online);
1250 }
1251
1252 module_init(arm_spe_pmu_init);
1253 module_exit(arm_spe_pmu_exit);
1254
1255 MODULE_DESCRIPTION("Perf driver for the ARMv8.2 Statistical Profiling Extension");
1256 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
1257 MODULE_LICENSE("GPL v2");