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/perf/arm_pmu.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/printk.h>
  33 #include <linux/slab.h>
  34 #include <linux/smp.h>
  35 #include <linux/vmalloc.h>
  36
  37 #include <asm/barrier.h>
  38 #include <asm/cpufeature.h>
  39 #include <asm/mmu.h>
  40 #include <asm/sysreg.h>
  41
  42 #define ARM_SPE_BUF_PAD_BYTE                    0
  43
  44 struct arm_spe_pmu_buf {
  45         int                                     nr_pages;
  46         bool                                    snapshot;
  47         void                                    *base;
  48 };
  49
  50 struct arm_spe_pmu {
  51         struct pmu                              pmu;
  52         struct platform_device                  *pdev;
  53         cpumask_t                               supported_cpus;
  54         struct hlist_node                       hotplug_node;
  55
  56         int                                     irq; /* PPI */
  57         u16                                     pmsver;
  58         u16                                     min_period;
  59         u16                                     counter_sz;
  60
  61 #define SPE_PMU_FEAT_FILT_EVT                   (1UL << 0)
  62 #define SPE_PMU_FEAT_FILT_TYP                   (1UL << 1)
  63 #define SPE_PMU_FEAT_FILT_LAT                   (1UL << 2)
  64 #define SPE_PMU_FEAT_ARCH_INST                  (1UL << 3)
  65 #define SPE_PMU_FEAT_LDS                        (1UL << 4)
  66 #define SPE_PMU_FEAT_ERND                       (1UL << 5)
  67 #define SPE_PMU_FEAT_DEV_PROBED                 (1UL << 63)
  68         u64                                     features;
  69
  70         u16                                     max_record_sz;
  71         u16                                     align;
  72         struct perf_output_handle __percpu      *handle;
  73 };
  74
  75 #define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))
  76
  77 /* Convert a free-running index from perf into an SPE buffer offset */
  78 #define PERF_IDX2OFF(idx, buf)  ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
  79
  80 /* Keep track of our dynamic hotplug state */
  81 static enum cpuhp_state arm_spe_pmu_online;
  82
  83 enum arm_spe_pmu_buf_fault_action {
  84         SPE_PMU_BUF_FAULT_ACT_SPURIOUS,
  85         SPE_PMU_BUF_FAULT_ACT_FATAL,
  86         SPE_PMU_BUF_FAULT_ACT_OK,
  87 };
  88
  89 /* This sysfs gunk was really good fun to write. */
  90 enum arm_spe_pmu_capabilities {
  91         SPE_PMU_CAP_ARCH_INST = 0,
  92         SPE_PMU_CAP_ERND,
  93         SPE_PMU_CAP_FEAT_MAX,
  94         SPE_PMU_CAP_CNT_SZ = SPE_PMU_CAP_FEAT_MAX,
  95         SPE_PMU_CAP_MIN_IVAL,
  96 };
  97
  98 static int arm_spe_pmu_feat_caps[SPE_PMU_CAP_FEAT_MAX] = {
  99         [SPE_PMU_CAP_ARCH_INST] = SPE_PMU_FEAT_ARCH_INST,
 100         [SPE_PMU_CAP_ERND]      = SPE_PMU_FEAT_ERND,
 101 };
 102
 103 static u32 arm_spe_pmu_cap_get(struct arm_spe_pmu *spe_pmu, int cap)
 104 {
 105         if (cap < SPE_PMU_CAP_FEAT_MAX)
 106                 return !!(spe_pmu->features & arm_spe_pmu_feat_caps[cap]);
 107
 108         switch (cap) {
 109         case SPE_PMU_CAP_CNT_SZ:
 110                 return spe_pmu->counter_sz;
 111         case SPE_PMU_CAP_MIN_IVAL:
 112                 return spe_pmu->min_period;
 113         default:
 114                 WARN(1, "unknown cap %d\n", cap);
 115         }
 116
 117         return 0;
 118 }
 119
 120 static ssize_t arm_spe_pmu_cap_show(struct device *dev,
 121                                     struct device_attribute *attr,
 122                                     char *buf)
 123 {
 124         struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
 125         struct dev_ext_attribute *ea =
 126                 container_of(attr, struct dev_ext_attribute, attr);
 127         int cap = (long)ea->var;
 128
 129         return sysfs_emit(buf, "%u\n", 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 const 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 const struct attribute_group arm_spe_pmu_format_group = {
 230         .name   = "format",
 231         .attrs  = arm_spe_pmu_formats_attr,
 232 };
 233
 234 static ssize_t cpumask_show(struct device *dev,
 235                             struct device_attribute *attr, char *buf)
 236 {
 237         struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
 238
 239         return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
 240 }
 241 static DEVICE_ATTR_RO(cpumask);
 242
 243 static struct attribute *arm_spe_pmu_attrs[] = {
 244         &dev_attr_cpumask.attr,
 245         NULL,
 246 };
 247
 248 static const struct attribute_group arm_spe_pmu_group = {
 249         .attrs  = arm_spe_pmu_attrs,
 250 };
 251
 252 static const struct attribute_group *arm_spe_pmu_attr_groups[] = {
 253         &arm_spe_pmu_group,
 254         &arm_spe_pmu_cap_group,
 255         &arm_spe_pmu_format_group,
 256         NULL,
 257 };
 258
 259 /* Convert between user ABI and register values */
 260 static u64 arm_spe_event_to_pmscr(struct perf_event *event)
 261 {
 262         struct perf_event_attr *attr = &event->attr;
 263         u64 reg = 0;
 264
 265         reg |= ATTR_CFG_GET_FLD(attr, ts_enable) << SYS_PMSCR_EL1_TS_SHIFT;
 266         reg |= ATTR_CFG_GET_FLD(attr, pa_enable) << SYS_PMSCR_EL1_PA_SHIFT;
 267         reg |= ATTR_CFG_GET_FLD(attr, pct_enable) << SYS_PMSCR_EL1_PCT_SHIFT;
 268
 269         if (!attr->exclude_user)
 270                 reg |= BIT(SYS_PMSCR_EL1_E0SPE_SHIFT);
 271
 272         if (!attr->exclude_kernel)
 273                 reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT);
 274
 275         if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && perfmon_capable())
 276                 reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT);
 277
 278         return reg;
 279 }
 280
 281 static void arm_spe_event_sanitise_period(struct perf_event *event)
 282 {
 283         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 284         u64 period = event->hw.sample_period;
 285         u64 max_period = SYS_PMSIRR_EL1_INTERVAL_MASK
 286                          << SYS_PMSIRR_EL1_INTERVAL_SHIFT;
 287
 288         if (period < spe_pmu->min_period)
 289                 period = spe_pmu->min_period;
 290         else if (period > max_period)
 291                 period = max_period;
 292         else
 293                 period &= max_period;
 294
 295         event->hw.sample_period = period;
 296 }
 297
 298 static u64 arm_spe_event_to_pmsirr(struct perf_event *event)
 299 {
 300         struct perf_event_attr *attr = &event->attr;
 301         u64 reg = 0;
 302
 303         arm_spe_event_sanitise_period(event);
 304
 305         reg |= ATTR_CFG_GET_FLD(attr, jitter) << SYS_PMSIRR_EL1_RND_SHIFT;
 306         reg |= event->hw.sample_period;
 307
 308         return reg;
 309 }
 310
 311 static u64 arm_spe_event_to_pmsfcr(struct perf_event *event)
 312 {
 313         struct perf_event_attr *attr = &event->attr;
 314         u64 reg = 0;
 315
 316         reg |= ATTR_CFG_GET_FLD(attr, load_filter) << SYS_PMSFCR_EL1_LD_SHIFT;
 317         reg |= ATTR_CFG_GET_FLD(attr, store_filter) << SYS_PMSFCR_EL1_ST_SHIFT;
 318         reg |= ATTR_CFG_GET_FLD(attr, branch_filter) << SYS_PMSFCR_EL1_B_SHIFT;
 319
 320         if (reg)
 321                 reg |= BIT(SYS_PMSFCR_EL1_FT_SHIFT);
 322
 323         if (ATTR_CFG_GET_FLD(attr, event_filter))
 324                 reg |= BIT(SYS_PMSFCR_EL1_FE_SHIFT);
 325
 326         if (ATTR_CFG_GET_FLD(attr, min_latency))
 327                 reg |= BIT(SYS_PMSFCR_EL1_FL_SHIFT);
 328
 329         return reg;
 330 }
 331
 332 static u64 arm_spe_event_to_pmsevfr(struct perf_event *event)
 333 {
 334         struct perf_event_attr *attr = &event->attr;
 335         return ATTR_CFG_GET_FLD(attr, event_filter);
 336 }
 337
 338 static u64 arm_spe_event_to_pmslatfr(struct perf_event *event)
 339 {
 340         struct perf_event_attr *attr = &event->attr;
 341         return ATTR_CFG_GET_FLD(attr, min_latency)
 342                << SYS_PMSLATFR_EL1_MINLAT_SHIFT;
 343 }
 344
 345 static void arm_spe_pmu_pad_buf(struct perf_output_handle *handle, int len)
 346 {
 347         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 348         u64 head = PERF_IDX2OFF(handle->head, buf);
 349
 350         memset(buf->base + head, ARM_SPE_BUF_PAD_BYTE, len);
 351         if (!buf->snapshot)
 352                 perf_aux_output_skip(handle, len);
 353 }
 354
 355 static u64 arm_spe_pmu_next_snapshot_off(struct perf_output_handle *handle)
 356 {
 357         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 358         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 359         u64 head = PERF_IDX2OFF(handle->head, buf);
 360         u64 limit = buf->nr_pages * PAGE_SIZE;
 361
 362         /*
 363          * The trace format isn't parseable in reverse, so clamp
 364          * the limit to half of the buffer size in snapshot mode
 365          * so that the worst case is half a buffer of records, as
 366          * opposed to a single record.
 367          */
 368         if (head < limit >> 1)
 369                 limit >>= 1;
 370
 371         /*
 372          * If we're within max_record_sz of the limit, we must
 373          * pad, move the head index and recompute the limit.
 374          */
 375         if (limit - head < spe_pmu->max_record_sz) {
 376                 arm_spe_pmu_pad_buf(handle, limit - head);
 377                 handle->head = PERF_IDX2OFF(limit, buf);
 378                 limit = ((buf->nr_pages * PAGE_SIZE) >> 1) + handle->head;
 379         }
 380
 381         return limit;
 382 }
 383
 384 static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle)
 385 {
 386         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 387         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 388         const u64 bufsize = buf->nr_pages * PAGE_SIZE;
 389         u64 limit = bufsize;
 390         u64 head, tail, wakeup;
 391
 392         /*
 393          * The head can be misaligned for two reasons:
 394          *
 395          * 1. The hardware left PMBPTR pointing to the first byte after
 396          *    a record when generating a buffer management event.
 397          *
 398          * 2. We used perf_aux_output_skip to consume handle->size bytes
 399          *    and CIRC_SPACE was used to compute the size, which always
 400          *    leaves one entry free.
 401          *
 402          * Deal with this by padding to the next alignment boundary and
 403          * moving the head index. If we run out of buffer space, we'll
 404          * reduce handle->size to zero and end up reporting truncation.
 405          */
 406         head = PERF_IDX2OFF(handle->head, buf);
 407         if (!IS_ALIGNED(head, spe_pmu->align)) {
 408                 unsigned long delta = roundup(head, spe_pmu->align) - head;
 409
 410                 delta = min(delta, handle->size);
 411                 arm_spe_pmu_pad_buf(handle, delta);
 412                 head = PERF_IDX2OFF(handle->head, buf);
 413         }
 414
 415         /* If we've run out of free space, then nothing more to do */
 416         if (!handle->size)
 417                 goto no_space;
 418
 419         /* Compute the tail and wakeup indices now that we've aligned head */
 420         tail = PERF_IDX2OFF(handle->head + handle->size, buf);
 421         wakeup = PERF_IDX2OFF(handle->wakeup, buf);
 422
 423         /*
 424          * Avoid clobbering unconsumed data. We know we have space, so
 425          * if we see head == tail we know that the buffer is empty. If
 426          * head > tail, then there's nothing to clobber prior to
 427          * wrapping.
 428          */
 429         if (head < tail)
 430                 limit = round_down(tail, PAGE_SIZE);
 431
 432         /*
 433          * Wakeup may be arbitrarily far into the future. If it's not in
 434          * the current generation, either we'll wrap before hitting it,
 435          * or it's in the past and has been handled already.
 436          *
 437          * If there's a wakeup before we wrap, arrange to be woken up by
 438          * the page boundary following it. Keep the tail boundary if
 439          * that's lower.
 440          */
 441         if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
 442                 limit = min(limit, round_up(wakeup, PAGE_SIZE));
 443
 444         if (limit > head)
 445                 return limit;
 446
 447         arm_spe_pmu_pad_buf(handle, handle->size);
 448 no_space:
 449         perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
 450         perf_aux_output_end(handle, 0);
 451         return 0;
 452 }
 453
 454 static u64 arm_spe_pmu_next_off(struct perf_output_handle *handle)
 455 {
 456         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 457         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 458         u64 limit = __arm_spe_pmu_next_off(handle);
 459         u64 head = PERF_IDX2OFF(handle->head, buf);
 460
 461         /*
 462          * If the head has come too close to the end of the buffer,
 463          * then pad to the end and recompute the limit.
 464          */
 465         if (limit && (limit - head < spe_pmu->max_record_sz)) {
 466                 arm_spe_pmu_pad_buf(handle, limit - head);
 467                 limit = __arm_spe_pmu_next_off(handle);
 468         }
 469
 470         return limit;
 471 }
 472
 473 static void arm_spe_perf_aux_output_begin(struct perf_output_handle *handle,
 474                                           struct perf_event *event)
 475 {
 476         u64 base, limit;
 477         struct arm_spe_pmu_buf *buf;
 478
 479         /* Start a new aux session */
 480         buf = perf_aux_output_begin(handle, event);
 481         if (!buf) {
 482                 event->hw.state |= PERF_HES_STOPPED;
 483                 /*
 484                  * We still need to clear the limit pointer, since the
 485                  * profiler might only be disabled by virtue of a fault.
 486                  */
 487                 limit = 0;
 488                 goto out_write_limit;
 489         }
 490
 491         limit = buf->snapshot ? arm_spe_pmu_next_snapshot_off(handle)
 492                               : arm_spe_pmu_next_off(handle);
 493         if (limit)
 494                 limit |= BIT(SYS_PMBLIMITR_EL1_E_SHIFT);
 495
 496         limit += (u64)buf->base;
 497         base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf);
 498         write_sysreg_s(base, SYS_PMBPTR_EL1);
 499
 500 out_write_limit:
 501         write_sysreg_s(limit, SYS_PMBLIMITR_EL1);
 502 }
 503
 504 static void arm_spe_perf_aux_output_end(struct perf_output_handle *handle)
 505 {
 506         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 507         u64 offset, size;
 508
 509         offset = read_sysreg_s(SYS_PMBPTR_EL1) - (u64)buf->base;
 510         size = offset - PERF_IDX2OFF(handle->head, buf);
 511
 512         if (buf->snapshot)
 513                 handle->head = offset;
 514
 515         perf_aux_output_end(handle, size);
 516 }
 517
 518 static void arm_spe_pmu_disable_and_drain_local(void)
 519 {
 520         /* Disable profiling at EL0 and EL1 */
 521         write_sysreg_s(0, SYS_PMSCR_EL1);
 522         isb();
 523
 524         /* Drain any buffered data */
 525         psb_csync();
 526         dsb(nsh);
 527
 528         /* Disable the profiling buffer */
 529         write_sysreg_s(0, SYS_PMBLIMITR_EL1);
 530         isb();
 531 }
 532
 533 /* IRQ handling */
 534 static enum arm_spe_pmu_buf_fault_action
 535 arm_spe_pmu_buf_get_fault_act(struct perf_output_handle *handle)
 536 {
 537         const char *err_str;
 538         u64 pmbsr;
 539         enum arm_spe_pmu_buf_fault_action ret;
 540
 541         /*
 542          * Ensure new profiling data is visible to the CPU and any external
 543          * aborts have been resolved.
 544          */
 545         psb_csync();
 546         dsb(nsh);
 547
 548         /* Ensure hardware updates to PMBPTR_EL1 are visible */
 549         isb();
 550
 551         /* Service required? */
 552         pmbsr = read_sysreg_s(SYS_PMBSR_EL1);
 553         if (!(pmbsr & BIT(SYS_PMBSR_EL1_S_SHIFT)))
 554                 return SPE_PMU_BUF_FAULT_ACT_SPURIOUS;
 555
 556         /*
 557          * If we've lost data, disable profiling and also set the PARTIAL
 558          * flag to indicate that the last record is corrupted.
 559          */
 560         if (pmbsr & BIT(SYS_PMBSR_EL1_DL_SHIFT))
 561                 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED |
 562                                              PERF_AUX_FLAG_PARTIAL);
 563
 564         /* Report collisions to userspace so that it can up the period */
 565         if (pmbsr & BIT(SYS_PMBSR_EL1_COLL_SHIFT))
 566                 perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
 567
 568         /* We only expect buffer management events */
 569         switch (pmbsr & (SYS_PMBSR_EL1_EC_MASK << SYS_PMBSR_EL1_EC_SHIFT)) {
 570         case SYS_PMBSR_EL1_EC_BUF:
 571                 /* Handled below */
 572                 break;
 573         case SYS_PMBSR_EL1_EC_FAULT_S1:
 574         case SYS_PMBSR_EL1_EC_FAULT_S2:
 575                 err_str = "Unexpected buffer fault";
 576                 goto out_err;
 577         default:
 578                 err_str = "Unknown error code";
 579                 goto out_err;
 580         }
 581
 582         /* Buffer management event */
 583         switch (pmbsr &
 584                 (SYS_PMBSR_EL1_BUF_BSC_MASK << SYS_PMBSR_EL1_BUF_BSC_SHIFT)) {
 585         case SYS_PMBSR_EL1_BUF_BSC_FULL:
 586                 ret = SPE_PMU_BUF_FAULT_ACT_OK;
 587                 goto out_stop;
 588         default:
 589                 err_str = "Unknown buffer status code";
 590         }
 591
 592 out_err:
 593         pr_err_ratelimited("%s on CPU %d [PMBSR=0x%016llx, PMBPTR=0x%016llx, PMBLIMITR=0x%016llx]\n",
 594                            err_str, smp_processor_id(), pmbsr,
 595                            read_sysreg_s(SYS_PMBPTR_EL1),
 596                            read_sysreg_s(SYS_PMBLIMITR_EL1));
 597         ret = SPE_PMU_BUF_FAULT_ACT_FATAL;
 598
 599 out_stop:
 600         arm_spe_perf_aux_output_end(handle);
 601         return ret;
 602 }
 603
 604 static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev)
 605 {
 606         struct perf_output_handle *handle = dev;
 607         struct perf_event *event = handle->event;
 608         enum arm_spe_pmu_buf_fault_action act;
 609
 610         if (!perf_get_aux(handle))
 611                 return IRQ_NONE;
 612
 613         act = arm_spe_pmu_buf_get_fault_act(handle);
 614         if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
 615                 return IRQ_NONE;
 616
 617         /*
 618          * Ensure perf callbacks have completed, which may disable the
 619          * profiling buffer in response to a TRUNCATION flag.
 620          */
 621         irq_work_run();
 622
 623         switch (act) {
 624         case SPE_PMU_BUF_FAULT_ACT_FATAL:
 625                 /*
 626                  * If a fatal exception occurred then leaving the profiling
 627                  * buffer enabled is a recipe waiting to happen. Since
 628                  * fatal faults don't always imply truncation, make sure
 629                  * that the profiling buffer is disabled explicitly before
 630                  * clearing the syndrome register.
 631                  */
 632                 arm_spe_pmu_disable_and_drain_local();
 633                 break;
 634         case SPE_PMU_BUF_FAULT_ACT_OK:
 635                 /*
 636                  * We handled the fault (the buffer was full), so resume
 637                  * profiling as long as we didn't detect truncation.
 638                  * PMBPTR might be misaligned, but we'll burn that bridge
 639                  * when we get to it.
 640                  */
 641                 if (!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)) {
 642                         arm_spe_perf_aux_output_begin(handle, event);
 643                         isb();
 644                 }
 645                 break;
 646         case SPE_PMU_BUF_FAULT_ACT_SPURIOUS:
 647                 /* We've seen you before, but GCC has the memory of a sieve. */
 648                 break;
 649         }
 650
 651         /* The buffer pointers are now sane, so resume profiling. */
 652         write_sysreg_s(0, SYS_PMBSR_EL1);
 653         return IRQ_HANDLED;
 654 }
 655
 656 static u64 arm_spe_pmsevfr_res0(u16 pmsver)
 657 {
 658         switch (pmsver) {
 659         case ID_AA64DFR0_PMSVER_8_2:
 660                 return SYS_PMSEVFR_EL1_RES0_8_2;
 661         case ID_AA64DFR0_PMSVER_8_3:
 662         /* Return the highest version we support in default */
 663         default:
 664                 return SYS_PMSEVFR_EL1_RES0_8_3;
 665         }
 666 }
 667
 668 /* Perf callbacks */
 669 static int arm_spe_pmu_event_init(struct perf_event *event)
 670 {
 671         u64 reg;
 672         struct perf_event_attr *attr = &event->attr;
 673         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 674
 675         /* This is, of course, deeply driver-specific */
 676         if (attr->type != event->pmu->type)
 677                 return -ENOENT;
 678
 679         if (event->cpu >= 0 &&
 680             !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus))
 681                 return -ENOENT;
 682
 683         if (arm_spe_event_to_pmsevfr(event) & arm_spe_pmsevfr_res0(spe_pmu->pmsver))
 684                 return -EOPNOTSUPP;
 685
 686         if (attr->exclude_idle)
 687                 return -EOPNOTSUPP;
 688
 689         /*
 690          * Feedback-directed frequency throttling doesn't work when we
 691          * have a buffer of samples. We'd need to manually count the
 692          * samples in the buffer when it fills up and adjust the event
 693          * count to reflect that. Instead, just force the user to specify
 694          * a sample period.
 695          */
 696         if (attr->freq)
 697                 return -EINVAL;
 698
 699         reg = arm_spe_event_to_pmsfcr(event);
 700         if ((reg & BIT(SYS_PMSFCR_EL1_FE_SHIFT)) &&
 701             !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT))
 702                 return -EOPNOTSUPP;
 703
 704         if ((reg & BIT(SYS_PMSFCR_EL1_FT_SHIFT)) &&
 705             !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP))
 706                 return -EOPNOTSUPP;
 707
 708         if ((reg & BIT(SYS_PMSFCR_EL1_FL_SHIFT)) &&
 709             !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
 710                 return -EOPNOTSUPP;
 711
 712         reg = arm_spe_event_to_pmscr(event);
 713         if (!perfmon_capable() &&
 714             (reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) |
 715                     BIT(SYS_PMSCR_EL1_CX_SHIFT) |
 716                     BIT(SYS_PMSCR_EL1_PCT_SHIFT))))
 717                 return -EACCES;
 718
 719         return 0;
 720 }
 721
 722 static void arm_spe_pmu_start(struct perf_event *event, int flags)
 723 {
 724         u64 reg;
 725         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 726         struct hw_perf_event *hwc = &event->hw;
 727         struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
 728
 729         hwc->state = 0;
 730         arm_spe_perf_aux_output_begin(handle, event);
 731         if (hwc->state)
 732                 return;
 733
 734         reg = arm_spe_event_to_pmsfcr(event);
 735         write_sysreg_s(reg, SYS_PMSFCR_EL1);
 736
 737         reg = arm_spe_event_to_pmsevfr(event);
 738         write_sysreg_s(reg, SYS_PMSEVFR_EL1);
 739
 740         reg = arm_spe_event_to_pmslatfr(event);
 741         write_sysreg_s(reg, SYS_PMSLATFR_EL1);
 742
 743         if (flags & PERF_EF_RELOAD) {
 744                 reg = arm_spe_event_to_pmsirr(event);
 745                 write_sysreg_s(reg, SYS_PMSIRR_EL1);
 746                 isb();
 747                 reg = local64_read(&hwc->period_left);
 748                 write_sysreg_s(reg, SYS_PMSICR_EL1);
 749         }
 750
 751         reg = arm_spe_event_to_pmscr(event);
 752         isb();
 753         write_sysreg_s(reg, SYS_PMSCR_EL1);
 754 }
 755
 756 static void arm_spe_pmu_stop(struct perf_event *event, int flags)
 757 {
 758         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 759         struct hw_perf_event *hwc = &event->hw;
 760         struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
 761
 762         /* If we're already stopped, then nothing to do */
 763         if (hwc->state & PERF_HES_STOPPED)
 764                 return;
 765
 766         /* Stop all trace generation */
 767         arm_spe_pmu_disable_and_drain_local();
 768
 769         if (flags & PERF_EF_UPDATE) {
 770                 /*
 771                  * If there's a fault pending then ensure we contain it
 772                  * to this buffer, since we might be on the context-switch
 773                  * path.
 774                  */
 775                 if (perf_get_aux(handle)) {
 776                         enum arm_spe_pmu_buf_fault_action act;
 777
 778                         act = arm_spe_pmu_buf_get_fault_act(handle);
 779                         if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
 780                                 arm_spe_perf_aux_output_end(handle);
 781                         else
 782                                 write_sysreg_s(0, SYS_PMBSR_EL1);
 783                 }
 784
 785                 /*
 786                  * This may also contain ECOUNT, but nobody else should
 787                  * be looking at period_left, since we forbid frequency
 788                  * based sampling.
 789                  */
 790                 local64_set(&hwc->period_left, read_sysreg_s(SYS_PMSICR_EL1));
 791                 hwc->state |= PERF_HES_UPTODATE;
 792         }
 793
 794         hwc->state |= PERF_HES_STOPPED;
 795 }
 796
 797 static int arm_spe_pmu_add(struct perf_event *event, int flags)
 798 {
 799         int ret = 0;
 800         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 801         struct hw_perf_event *hwc = &event->hw;
 802         int cpu = event->cpu == -1 ? smp_processor_id() : event->cpu;
 803
 804         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
 805                 return -ENOENT;
 806
 807         hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
 808
 809         if (flags & PERF_EF_START) {
 810                 arm_spe_pmu_start(event, PERF_EF_RELOAD);
 811                 if (hwc->state & PERF_HES_STOPPED)
 812                         ret = -EINVAL;
 813         }
 814
 815         return ret;
 816 }
 817
 818 static void arm_spe_pmu_del(struct perf_event *event, int flags)
 819 {
 820         arm_spe_pmu_stop(event, PERF_EF_UPDATE);
 821 }
 822
 823 static void arm_spe_pmu_read(struct perf_event *event)
 824 {
 825 }
 826
 827 static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
 828                                    int nr_pages, bool snapshot)
 829 {
 830         int i, cpu = event->cpu;
 831         struct page **pglist;
 832         struct arm_spe_pmu_buf *buf;
 833
 834         /* We need at least two pages for this to work. */
 835         if (nr_pages < 2)
 836                 return NULL;
 837
 838         /*
 839          * We require an even number of pages for snapshot mode, so that
 840          * we can effectively treat the buffer as consisting of two equal
 841          * parts and give userspace a fighting chance of getting some
 842          * useful data out of it.
 843          */
 844         if (snapshot && (nr_pages & 1))
 845                 return NULL;
 846
 847         if (cpu == -1)
 848                 cpu = raw_smp_processor_id();
 849
 850         buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, cpu_to_node(cpu));
 851         if (!buf)
 852                 return NULL;
 853
 854         pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
 855         if (!pglist)
 856                 goto out_free_buf;
 857
 858         for (i = 0; i < nr_pages; ++i)
 859                 pglist[i] = virt_to_page(pages[i]);
 860
 861         buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
 862         if (!buf->base)
 863                 goto out_free_pglist;
 864
 865         buf->nr_pages   = nr_pages;
 866         buf->snapshot   = snapshot;
 867
 868         kfree(pglist);
 869         return buf;
 870
 871 out_free_pglist:
 872         kfree(pglist);
 873 out_free_buf:
 874         kfree(buf);
 875         return NULL;
 876 }
 877
 878 static void arm_spe_pmu_free_aux(void *aux)
 879 {
 880         struct arm_spe_pmu_buf *buf = aux;
 881
 882         vunmap(buf->base);
 883         kfree(buf);
 884 }
 885
 886 /* Initialisation and teardown functions */
 887 static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
 888 {
 889         static atomic_t pmu_idx = ATOMIC_INIT(-1);
 890
 891         int idx;
 892         char *name;
 893         struct device *dev = &spe_pmu->pdev->dev;
 894
 895         spe_pmu->pmu = (struct pmu) {
 896                 .module = THIS_MODULE,
 897                 .capabilities   = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
 898                 .attr_groups    = arm_spe_pmu_attr_groups,
 899                 /*
 900                  * We hitch a ride on the software context here, so that
 901                  * we can support per-task profiling (which is not possible
 902                  * with the invalid context as it doesn't get sched callbacks).
 903                  * This requires that userspace either uses a dummy event for
 904                  * perf_event_open, since the aux buffer is not setup until
 905                  * a subsequent mmap, or creates the profiling event in a
 906                  * disabled state and explicitly PERF_EVENT_IOC_ENABLEs it
 907                  * once the buffer has been created.
 908                  */
 909                 .task_ctx_nr    = perf_sw_context,
 910                 .event_init     = arm_spe_pmu_event_init,
 911                 .add            = arm_spe_pmu_add,
 912                 .del            = arm_spe_pmu_del,
 913                 .start          = arm_spe_pmu_start,
 914                 .stop           = arm_spe_pmu_stop,
 915                 .read           = arm_spe_pmu_read,
 916                 .setup_aux      = arm_spe_pmu_setup_aux,
 917                 .free_aux       = arm_spe_pmu_free_aux,
 918         };
 919
 920         idx = atomic_inc_return(&pmu_idx);
 921         name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx);
 922         if (!name) {
 923                 dev_err(dev, "failed to allocate name for pmu %d\n", idx);
 924                 return -ENOMEM;
 925         }
 926
 927         return perf_pmu_register(&spe_pmu->pmu, name, -1);
 928 }
 929
 930 static void arm_spe_pmu_perf_destroy(struct arm_spe_pmu *spe_pmu)
 931 {
 932         perf_pmu_unregister(&spe_pmu->pmu);
 933 }
 934
 935 static void __arm_spe_pmu_dev_probe(void *info)
 936 {
 937         int fld;
 938         u64 reg;
 939         struct arm_spe_pmu *spe_pmu = info;
 940         struct device *dev = &spe_pmu->pdev->dev;
 941
 942         fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64DFR0_EL1),
 943                                                    ID_AA64DFR0_PMSVER_SHIFT);
 944         if (!fld) {
 945                 dev_err(dev,
 946                         "unsupported ID_AA64DFR0_EL1.PMSVer [%d] on CPU %d\n",
 947                         fld, smp_processor_id());
 948                 return;
 949         }
 950         spe_pmu->pmsver = (u16)fld;
 951
 952         /* Read PMBIDR first to determine whether or not we have access */
 953         reg = read_sysreg_s(SYS_PMBIDR_EL1);
 954         if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT)) {
 955                 dev_err(dev,
 956                         "profiling buffer owned by higher exception level\n");
 957                 return;
 958         }
 959
 960         /* Minimum alignment. If it's out-of-range, then fail the probe */
 961         fld = reg >> SYS_PMBIDR_EL1_ALIGN_SHIFT & SYS_PMBIDR_EL1_ALIGN_MASK;
 962         spe_pmu->align = 1 << fld;
 963         if (spe_pmu->align > SZ_2K) {
 964                 dev_err(dev, "unsupported PMBIDR.Align [%d] on CPU %d\n",
 965                         fld, smp_processor_id());
 966                 return;
 967         }
 968
 969         /* It's now safe to read PMSIDR and figure out what we've got */
 970         reg = read_sysreg_s(SYS_PMSIDR_EL1);
 971         if (reg & BIT(SYS_PMSIDR_EL1_FE_SHIFT))
 972                 spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT;
 973
 974         if (reg & BIT(SYS_PMSIDR_EL1_FT_SHIFT))
 975                 spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP;
 976
 977         if (reg & BIT(SYS_PMSIDR_EL1_FL_SHIFT))
 978                 spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT;
 979
 980         if (reg & BIT(SYS_PMSIDR_EL1_ARCHINST_SHIFT))
 981                 spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST;
 982
 983         if (reg & BIT(SYS_PMSIDR_EL1_LDS_SHIFT))
 984                 spe_pmu->features |= SPE_PMU_FEAT_LDS;
 985
 986         if (reg & BIT(SYS_PMSIDR_EL1_ERND_SHIFT))
 987                 spe_pmu->features |= SPE_PMU_FEAT_ERND;
 988
 989         /* This field has a spaced out encoding, so just use a look-up */
 990         fld = reg >> SYS_PMSIDR_EL1_INTERVAL_SHIFT & SYS_PMSIDR_EL1_INTERVAL_MASK;
 991         switch (fld) {
 992         case 0:
 993                 spe_pmu->min_period = 256;
 994                 break;
 995         case 2:
 996                 spe_pmu->min_period = 512;
 997                 break;
 998         case 3:
 999                 spe_pmu->min_period = 768;
1000                 break;
1001         case 4:
1002                 spe_pmu->min_period = 1024;
1003                 break;
1004         case 5:
1005                 spe_pmu->min_period = 1536;
1006                 break;
1007         case 6:
1008                 spe_pmu->min_period = 2048;
1009                 break;
1010         case 7:
1011                 spe_pmu->min_period = 3072;
1012                 break;
1013         default:
1014                 dev_warn(dev, "unknown PMSIDR_EL1.Interval [%d]; assuming 8\n",
1015                          fld);
1016                 fallthrough;
1017         case 8:
1018                 spe_pmu->min_period = 4096;
1019         }
1020
1021         /* Maximum record size. If it's out-of-range, then fail the probe */
1022         fld = reg >> SYS_PMSIDR_EL1_MAXSIZE_SHIFT & SYS_PMSIDR_EL1_MAXSIZE_MASK;
1023         spe_pmu->max_record_sz = 1 << fld;
1024         if (spe_pmu->max_record_sz > SZ_2K || spe_pmu->max_record_sz < 16) {
1025                 dev_err(dev, "unsupported PMSIDR_EL1.MaxSize [%d] on CPU %d\n",
1026                         fld, smp_processor_id());
1027                 return;
1028         }
1029
1030         fld = reg >> SYS_PMSIDR_EL1_COUNTSIZE_SHIFT & SYS_PMSIDR_EL1_COUNTSIZE_MASK;
1031         switch (fld) {
1032         default:
1033                 dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n",
1034                          fld);
1035                 fallthrough;
1036         case 2:
1037                 spe_pmu->counter_sz = 12;
1038                 break;
1039         case 3:
1040                 spe_pmu->counter_sz = 16;
1041         }
1042
1043         dev_info(dev,
1044                  "probed for CPUs %*pbl [max_record_sz %u, align %u, features 0x%llx]\n",
1045                  cpumask_pr_args(&spe_pmu->supported_cpus),
1046                  spe_pmu->max_record_sz, spe_pmu->align, spe_pmu->features);
1047
1048         spe_pmu->features |= SPE_PMU_FEAT_DEV_PROBED;
1049 }
1050
1051 static void __arm_spe_pmu_reset_local(void)
1052 {
1053         /*
1054          * This is probably overkill, as we have no idea where we're
1055          * draining any buffered data to...
1056          */
1057         arm_spe_pmu_disable_and_drain_local();
1058
1059         /* Reset the buffer base pointer */
1060         write_sysreg_s(0, SYS_PMBPTR_EL1);
1061         isb();
1062
1063         /* Clear any pending management interrupts */
1064         write_sysreg_s(0, SYS_PMBSR_EL1);
1065         isb();
1066 }
1067
1068 static void __arm_spe_pmu_setup_one(void *info)
1069 {
1070         struct arm_spe_pmu *spe_pmu = info;
1071
1072         __arm_spe_pmu_reset_local();
1073         enable_percpu_irq(spe_pmu->irq, IRQ_TYPE_NONE);
1074 }
1075
1076 static void __arm_spe_pmu_stop_one(void *info)
1077 {
1078         struct arm_spe_pmu *spe_pmu = info;
1079
1080         disable_percpu_irq(spe_pmu->irq);
1081         __arm_spe_pmu_reset_local();
1082 }
1083
1084 static int arm_spe_pmu_cpu_startup(unsigned int cpu, struct hlist_node *node)
1085 {
1086         struct arm_spe_pmu *spe_pmu;
1087
1088         spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1089         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1090                 return 0;
1091
1092         __arm_spe_pmu_setup_one(spe_pmu);
1093         return 0;
1094 }
1095
1096 static int arm_spe_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
1097 {
1098         struct arm_spe_pmu *spe_pmu;
1099
1100         spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1101         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1102                 return 0;
1103
1104         __arm_spe_pmu_stop_one(spe_pmu);
1105         return 0;
1106 }
1107
1108 static int arm_spe_pmu_dev_init(struct arm_spe_pmu *spe_pmu)
1109 {
1110         int ret;
1111         cpumask_t *mask = &spe_pmu->supported_cpus;
1112
1113         /* Make sure we probe the hardware on a relevant CPU */
1114         ret = smp_call_function_any(mask,  __arm_spe_pmu_dev_probe, spe_pmu, 1);
1115         if (ret || !(spe_pmu->features & SPE_PMU_FEAT_DEV_PROBED))
1116                 return -ENXIO;
1117
1118         /* Request our PPIs (note that the IRQ is still disabled) */
1119         ret = request_percpu_irq(spe_pmu->irq, arm_spe_pmu_irq_handler, DRVNAME,
1120                                  spe_pmu->handle);
1121         if (ret)
1122                 return ret;
1123
1124         /*
1125          * Register our hotplug notifier now so we don't miss any events.
1126          * This will enable the IRQ for any supported CPUs that are already
1127          * up.
1128          */
1129         ret = cpuhp_state_add_instance(arm_spe_pmu_online,
1130                                        &spe_pmu->hotplug_node);
1131         if (ret)
1132                 free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1133
1134         return ret;
1135 }
1136
1137 static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu)
1138 {
1139         cpuhp_state_remove_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node);
1140         free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1141 }
1142
1143 /* Driver and device probing */
1144 static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu)
1145 {
1146         struct platform_device *pdev = spe_pmu->pdev;
1147         int irq = platform_get_irq(pdev, 0);
1148
1149         if (irq < 0)
1150                 return -ENXIO;
1151
1152         if (!irq_is_percpu(irq)) {
1153                 dev_err(&pdev->dev, "expected PPI but got SPI (%d)\n", irq);
1154                 return -EINVAL;
1155         }
1156
1157         if (irq_get_percpu_devid_partition(irq, &spe_pmu->supported_cpus)) {
1158                 dev_err(&pdev->dev, "failed to get PPI partition (%d)\n", irq);
1159                 return -EINVAL;
1160         }
1161
1162         spe_pmu->irq = irq;
1163         return 0;
1164 }
1165
1166 static const struct of_device_id arm_spe_pmu_of_match[] = {
1167         { .compatible = "arm,statistical-profiling-extension-v1", .data = (void *)1 },
1168         { /* Sentinel */ },
1169 };
1170 MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
1171
1172 static const struct platform_device_id arm_spe_match[] = {
1173         { ARMV8_SPE_PDEV_NAME, 0},
1174         { }
1175 };
1176 MODULE_DEVICE_TABLE(platform, arm_spe_match);
1177
1178 static int arm_spe_pmu_device_probe(struct platform_device *pdev)
1179 {
1180         int ret;
1181         struct arm_spe_pmu *spe_pmu;
1182         struct device *dev = &pdev->dev;
1183
1184         /*
1185          * If kernelspace is unmapped when running at EL0, then the SPE
1186          * buffer will fault and prematurely terminate the AUX session.
1187          */
1188         if (arm64_kernel_unmapped_at_el0()) {
1189                 dev_warn_once(dev, "profiling buffer inaccessible. Try passing \"kpti=off\" on the kernel command line\n");
1190                 return -EPERM;
1191         }
1192
1193         spe_pmu = devm_kzalloc(dev, sizeof(*spe_pmu), GFP_KERNEL);
1194         if (!spe_pmu)
1195                 return -ENOMEM;
1196
1197         spe_pmu->handle = alloc_percpu(typeof(*spe_pmu->handle));
1198         if (!spe_pmu->handle)
1199                 return -ENOMEM;
1200
1201         spe_pmu->pdev = pdev;
1202         platform_set_drvdata(pdev, spe_pmu);
1203
1204         ret = arm_spe_pmu_irq_probe(spe_pmu);
1205         if (ret)
1206                 goto out_free_handle;
1207
1208         ret = arm_spe_pmu_dev_init(spe_pmu);
1209         if (ret)
1210                 goto out_free_handle;
1211
1212         ret = arm_spe_pmu_perf_init(spe_pmu);
1213         if (ret)
1214                 goto out_teardown_dev;
1215
1216         return 0;
1217
1218 out_teardown_dev:
1219         arm_spe_pmu_dev_teardown(spe_pmu);
1220 out_free_handle:
1221         free_percpu(spe_pmu->handle);
1222         return ret;
1223 }
1224
1225 static int arm_spe_pmu_device_remove(struct platform_device *pdev)
1226 {
1227         struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
1228
1229         arm_spe_pmu_perf_destroy(spe_pmu);
1230         arm_spe_pmu_dev_teardown(spe_pmu);
1231         free_percpu(spe_pmu->handle);
1232         return 0;
1233 }
1234
1235 static struct platform_driver arm_spe_pmu_driver = {
1236         .id_table = arm_spe_match,
1237         .driver = {
1238                 .name           = DRVNAME,
1239                 .of_match_table = of_match_ptr(arm_spe_pmu_of_match),
1240                 .suppress_bind_attrs = true,
1241         },
1242         .probe  = arm_spe_pmu_device_probe,
1243         .remove = arm_spe_pmu_device_remove,
1244 };
1245
1246 static int __init arm_spe_pmu_init(void)
1247 {
1248         int ret;
1249
1250         ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
1251                                       arm_spe_pmu_cpu_startup,
1252                                       arm_spe_pmu_cpu_teardown);
1253         if (ret < 0)
1254                 return ret;
1255         arm_spe_pmu_online = ret;
1256
1257         ret = platform_driver_register(&arm_spe_pmu_driver);
1258         if (ret)
1259                 cpuhp_remove_multi_state(arm_spe_pmu_online);
1260
1261         return ret;
1262 }
1263
1264 static void __exit arm_spe_pmu_exit(void)
1265 {
1266         platform_driver_unregister(&arm_spe_pmu_driver);
1267         cpuhp_remove_multi_state(arm_spe_pmu_online);
1268 }
1269
1270 module_init(arm_spe_pmu_init);
1271 module_exit(arm_spe_pmu_exit);
1272
1273 MODULE_DESCRIPTION("Perf driver for the ARMv8.2 Statistical Profiling Extension");
1274 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
1275 MODULE_LICENSE("GPL v2");