drivers/perf/arm_spe

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This source file includes following definitions.
arm_spe_pmu_cap_get
arm_spe_pmu_cap_show
arm_spe_pmu_get_attr_cpumask
arm_spe_event_to_pmscr
arm_spe_event_sanitise_period
arm_spe_event_to_pmsirr
arm_spe_event_to_pmsfcr
arm_spe_event_to_pmsevfr
arm_spe_event_to_pmslatfr
arm_spe_pmu_pad_buf
arm_spe_pmu_next_snapshot_off
__arm_spe_pmu_next_off
arm_spe_pmu_next_off
arm_spe_perf_aux_output_begin
arm_spe_perf_aux_output_end
arm_spe_pmu_disable_and_drain_local
arm_spe_pmu_buf_get_fault_act
arm_spe_pmu_irq_handler
arm_spe_pmu_event_init
arm_spe_pmu_start
arm_spe_pmu_stop
arm_spe_pmu_add
arm_spe_pmu_del
arm_spe_pmu_read
arm_spe_pmu_setup_aux
arm_spe_pmu_free_aux
arm_spe_pmu_perf_init
arm_spe_pmu_perf_destroy
__arm_spe_pmu_dev_probe
__arm_spe_pmu_reset_local
__arm_spe_pmu_setup_one
__arm_spe_pmu_stop_one
arm_spe_pmu_cpu_startup
arm_spe_pmu_cpu_teardown
arm_spe_pmu_dev_init
arm_spe_pmu_dev_teardown
arm_spe_pmu_irq_probe
arm_spe_pmu_device_probe
arm_spe_pmu_device_remove
arm_spe_pmu_init
arm_spe_pmu_exit
   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 
  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 snprintf(buf, PAGE_SIZE, "%u\n",
 130                 arm_spe_pmu_cap_get(spe_pmu, cap));
 131 }
 132 
 133 #define SPE_EXT_ATTR_ENTRY(_name, _func, _var)                          \
 134         &((struct dev_ext_attribute[]) {                                \
 135                 { __ATTR(_name, S_IRUGO, _func, NULL), (void *)_var }   \
 136         })[0].attr.attr
 137 
 138 #define SPE_CAP_EXT_ATTR_ENTRY(_name, _var)                             \
 139         SPE_EXT_ATTR_ENTRY(_name, arm_spe_pmu_cap_show, _var)
 140 
 141 static struct attribute *arm_spe_pmu_cap_attr[] = {
 142         SPE_CAP_EXT_ATTR_ENTRY(arch_inst, SPE_PMU_CAP_ARCH_INST),
 143         SPE_CAP_EXT_ATTR_ENTRY(ernd, SPE_PMU_CAP_ERND),
 144         SPE_CAP_EXT_ATTR_ENTRY(count_size, SPE_PMU_CAP_CNT_SZ),
 145         SPE_CAP_EXT_ATTR_ENTRY(min_interval, SPE_PMU_CAP_MIN_IVAL),
 146         NULL,
 147 };
 148 
 149 static struct attribute_group arm_spe_pmu_cap_group = {
 150         .name   = "caps",
 151         .attrs  = arm_spe_pmu_cap_attr,
 152 };
 153 
 154 /* User ABI */
 155 #define ATTR_CFG_FLD_ts_enable_CFG              config  /* PMSCR_EL1.TS */
 156 #define ATTR_CFG_FLD_ts_enable_LO               0
 157 #define ATTR_CFG_FLD_ts_enable_HI               0
 158 #define ATTR_CFG_FLD_pa_enable_CFG              config  /* PMSCR_EL1.PA */
 159 #define ATTR_CFG_FLD_pa_enable_LO               1
 160 #define ATTR_CFG_FLD_pa_enable_HI               1
 161 #define ATTR_CFG_FLD_pct_enable_CFG             config  /* PMSCR_EL1.PCT */
 162 #define ATTR_CFG_FLD_pct_enable_LO              2
 163 #define ATTR_CFG_FLD_pct_enable_HI              2
 164 #define ATTR_CFG_FLD_jitter_CFG                 config  /* PMSIRR_EL1.RND */
 165 #define ATTR_CFG_FLD_jitter_LO                  16
 166 #define ATTR_CFG_FLD_jitter_HI                  16
 167 #define ATTR_CFG_FLD_branch_filter_CFG          config  /* PMSFCR_EL1.B */
 168 #define ATTR_CFG_FLD_branch_filter_LO           32
 169 #define ATTR_CFG_FLD_branch_filter_HI           32
 170 #define ATTR_CFG_FLD_load_filter_CFG            config  /* PMSFCR_EL1.LD */
 171 #define ATTR_CFG_FLD_load_filter_LO             33
 172 #define ATTR_CFG_FLD_load_filter_HI             33
 173 #define ATTR_CFG_FLD_store_filter_CFG           config  /* PMSFCR_EL1.ST */
 174 #define ATTR_CFG_FLD_store_filter_LO            34
 175 #define ATTR_CFG_FLD_store_filter_HI            34
 176 
 177 #define ATTR_CFG_FLD_event_filter_CFG           config1 /* PMSEVFR_EL1 */
 178 #define ATTR_CFG_FLD_event_filter_LO            0
 179 #define ATTR_CFG_FLD_event_filter_HI            63
 180 
 181 #define ATTR_CFG_FLD_min_latency_CFG            config2 /* PMSLATFR_EL1.MINLAT */
 182 #define ATTR_CFG_FLD_min_latency_LO             0
 183 #define ATTR_CFG_FLD_min_latency_HI             11
 184 
 185 /* Why does everything I do descend into this? */
 186 #define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi)                              \
 187         (lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi
 188 
 189 #define _GEN_PMU_FORMAT_ATTR(cfg, lo, hi)                               \
 190         __GEN_PMU_FORMAT_ATTR(cfg, lo, hi)
 191 
 192 #define GEN_PMU_FORMAT_ATTR(name)                                       \
 193         PMU_FORMAT_ATTR(name,                                           \
 194         _GEN_PMU_FORMAT_ATTR(ATTR_CFG_FLD_##name##_CFG,                 \
 195                              ATTR_CFG_FLD_##name##_LO,                  \
 196                              ATTR_CFG_FLD_##name##_HI))
 197 
 198 #define _ATTR_CFG_GET_FLD(attr, cfg, lo, hi)                            \
 199         ((((attr)->cfg) >> lo) & GENMASK(hi - lo, 0))
 200 
 201 #define ATTR_CFG_GET_FLD(attr, name)                                    \
 202         _ATTR_CFG_GET_FLD(attr,                                         \
 203                           ATTR_CFG_FLD_##name##_CFG,                    \
 204                           ATTR_CFG_FLD_##name##_LO,                     \
 205                           ATTR_CFG_FLD_##name##_HI)
 206 
 207 GEN_PMU_FORMAT_ATTR(ts_enable);
 208 GEN_PMU_FORMAT_ATTR(pa_enable);
 209 GEN_PMU_FORMAT_ATTR(pct_enable);
 210 GEN_PMU_FORMAT_ATTR(jitter);
 211 GEN_PMU_FORMAT_ATTR(branch_filter);
 212 GEN_PMU_FORMAT_ATTR(load_filter);
 213 GEN_PMU_FORMAT_ATTR(store_filter);
 214 GEN_PMU_FORMAT_ATTR(event_filter);
 215 GEN_PMU_FORMAT_ATTR(min_latency);
 216 
 217 static struct attribute *arm_spe_pmu_formats_attr[] = {
 218         &format_attr_ts_enable.attr,
 219         &format_attr_pa_enable.attr,
 220         &format_attr_pct_enable.attr,
 221         &format_attr_jitter.attr,
 222         &format_attr_branch_filter.attr,
 223         &format_attr_load_filter.attr,
 224         &format_attr_store_filter.attr,
 225         &format_attr_event_filter.attr,
 226         &format_attr_min_latency.attr,
 227         NULL,
 228 };
 229 
 230 static struct attribute_group arm_spe_pmu_format_group = {
 231         .name   = "format",
 232         .attrs  = arm_spe_pmu_formats_attr,
 233 };
 234 
 235 static ssize_t arm_spe_pmu_get_attr_cpumask(struct device *dev,
 236                                             struct device_attribute *attr,
 237                                             char *buf)
 238 {
 239         struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
 240 
 241         return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
 242 }
 243 static DEVICE_ATTR(cpumask, S_IRUGO, arm_spe_pmu_get_attr_cpumask, NULL);
 244 
 245 static struct attribute *arm_spe_pmu_attrs[] = {
 246         &dev_attr_cpumask.attr,
 247         NULL,
 248 };
 249 
 250 static struct attribute_group arm_spe_pmu_group = {
 251         .attrs  = arm_spe_pmu_attrs,
 252 };
 253 
 254 static const struct attribute_group *arm_spe_pmu_attr_groups[] = {
 255         &arm_spe_pmu_group,
 256         &arm_spe_pmu_cap_group,
 257         &arm_spe_pmu_format_group,
 258         NULL,
 259 };
 260 
 261 /* Convert between user ABI and register values */
 262 static u64 arm_spe_event_to_pmscr(struct perf_event *event)
 263 {
 264         struct perf_event_attr *attr = &event->attr;
 265         u64 reg = 0;
 266 
 267         reg |= ATTR_CFG_GET_FLD(attr, ts_enable) << SYS_PMSCR_EL1_TS_SHIFT;
 268         reg |= ATTR_CFG_GET_FLD(attr, pa_enable) << SYS_PMSCR_EL1_PA_SHIFT;
 269         reg |= ATTR_CFG_GET_FLD(attr, pct_enable) << SYS_PMSCR_EL1_PCT_SHIFT;
 270 
 271         if (!attr->exclude_user)
 272                 reg |= BIT(SYS_PMSCR_EL1_E0SPE_SHIFT);
 273 
 274         if (!attr->exclude_kernel)
 275                 reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT);
 276 
 277         if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && capable(CAP_SYS_ADMIN))
 278                 reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT);
 279 
 280         return reg;
 281 }
 282 
 283 static void arm_spe_event_sanitise_period(struct perf_event *event)
 284 {
 285         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 286         u64 period = event->hw.sample_period;
 287         u64 max_period = SYS_PMSIRR_EL1_INTERVAL_MASK
 288                          << SYS_PMSIRR_EL1_INTERVAL_SHIFT;
 289 
 290         if (period < spe_pmu->min_period)
 291                 period = spe_pmu->min_period;
 292         else if (period > max_period)
 293                 period = max_period;
 294         else
 295                 period &= max_period;
 296 
 297         event->hw.sample_period = period;
 298 }
 299 
 300 static u64 arm_spe_event_to_pmsirr(struct perf_event *event)
 301 {
 302         struct perf_event_attr *attr = &event->attr;
 303         u64 reg = 0;
 304 
 305         arm_spe_event_sanitise_period(event);
 306 
 307         reg |= ATTR_CFG_GET_FLD(attr, jitter) << SYS_PMSIRR_EL1_RND_SHIFT;
 308         reg |= event->hw.sample_period;
 309 
 310         return reg;
 311 }
 312 
 313 static u64 arm_spe_event_to_pmsfcr(struct perf_event *event)
 314 {
 315         struct perf_event_attr *attr = &event->attr;
 316         u64 reg = 0;
 317 
 318         reg |= ATTR_CFG_GET_FLD(attr, load_filter) << SYS_PMSFCR_EL1_LD_SHIFT;
 319         reg |= ATTR_CFG_GET_FLD(attr, store_filter) << SYS_PMSFCR_EL1_ST_SHIFT;
 320         reg |= ATTR_CFG_GET_FLD(attr, branch_filter) << SYS_PMSFCR_EL1_B_SHIFT;
 321 
 322         if (reg)
 323                 reg |= BIT(SYS_PMSFCR_EL1_FT_SHIFT);
 324 
 325         if (ATTR_CFG_GET_FLD(attr, event_filter))
 326                 reg |= BIT(SYS_PMSFCR_EL1_FE_SHIFT);
 327 
 328         if (ATTR_CFG_GET_FLD(attr, min_latency))
 329                 reg |= BIT(SYS_PMSFCR_EL1_FL_SHIFT);
 330 
 331         return reg;
 332 }
 333 
 334 static u64 arm_spe_event_to_pmsevfr(struct perf_event *event)
 335 {
 336         struct perf_event_attr *attr = &event->attr;
 337         return ATTR_CFG_GET_FLD(attr, event_filter);
 338 }
 339 
 340 static u64 arm_spe_event_to_pmslatfr(struct perf_event *event)
 341 {
 342         struct perf_event_attr *attr = &event->attr;
 343         return ATTR_CFG_GET_FLD(attr, min_latency)
 344                << SYS_PMSLATFR_EL1_MINLAT_SHIFT;
 345 }
 346 
 347 static void arm_spe_pmu_pad_buf(struct perf_output_handle *handle, int len)
 348 {
 349         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 350         u64 head = PERF_IDX2OFF(handle->head, buf);
 351 
 352         memset(buf->base + head, ARM_SPE_BUF_PAD_BYTE, len);
 353         if (!buf->snapshot)
 354                 perf_aux_output_skip(handle, len);
 355 }
 356 
 357 static u64 arm_spe_pmu_next_snapshot_off(struct perf_output_handle *handle)
 358 {
 359         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 360         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 361         u64 head = PERF_IDX2OFF(handle->head, buf);
 362         u64 limit = buf->nr_pages * PAGE_SIZE;
 363 
 364         /*
 365          * The trace format isn't parseable in reverse, so clamp
 366          * the limit to half of the buffer size in snapshot mode
 367          * so that the worst case is half a buffer of records, as
 368          * opposed to a single record.
 369          */
 370         if (head < limit >> 1)
 371                 limit >>= 1;
 372 
 373         /*
 374          * If we're within max_record_sz of the limit, we must
 375          * pad, move the head index and recompute the limit.
 376          */
 377         if (limit - head < spe_pmu->max_record_sz) {
 378                 arm_spe_pmu_pad_buf(handle, limit - head);
 379                 handle->head = PERF_IDX2OFF(limit, buf);
 380                 limit = ((buf->nr_pages * PAGE_SIZE) >> 1) + handle->head;
 381         }
 382 
 383         return limit;
 384 }
 385 
 386 static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle)
 387 {
 388         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 389         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 390         const u64 bufsize = buf->nr_pages * PAGE_SIZE;
 391         u64 limit = bufsize;
 392         u64 head, tail, wakeup;
 393 
 394         /*
 395          * The head can be misaligned for two reasons:
 396          *
 397          * 1. The hardware left PMBPTR pointing to the first byte after
 398          *    a record when generating a buffer management event.
 399          *
 400          * 2. We used perf_aux_output_skip to consume handle->size bytes
 401          *    and CIRC_SPACE was used to compute the size, which always
 402          *    leaves one entry free.
 403          *
 404          * Deal with this by padding to the next alignment boundary and
 405          * moving the head index. If we run out of buffer space, we'll
 406          * reduce handle->size to zero and end up reporting truncation.
 407          */
 408         head = PERF_IDX2OFF(handle->head, buf);
 409         if (!IS_ALIGNED(head, spe_pmu->align)) {
 410                 unsigned long delta = roundup(head, spe_pmu->align) - head;
 411 
 412                 delta = min(delta, handle->size);
 413                 arm_spe_pmu_pad_buf(handle, delta);
 414                 head = PERF_IDX2OFF(handle->head, buf);
 415         }
 416 
 417         /* If we've run out of free space, then nothing more to do */
 418         if (!handle->size)
 419                 goto no_space;
 420 
 421         /* Compute the tail and wakeup indices now that we've aligned head */
 422         tail = PERF_IDX2OFF(handle->head + handle->size, buf);
 423         wakeup = PERF_IDX2OFF(handle->wakeup, buf);
 424 
 425         /*
 426          * Avoid clobbering unconsumed data. We know we have space, so
 427          * if we see head == tail we know that the buffer is empty. If
 428          * head > tail, then there's nothing to clobber prior to
 429          * wrapping.
 430          */
 431         if (head < tail)
 432                 limit = round_down(tail, PAGE_SIZE);
 433 
 434         /*
 435          * Wakeup may be arbitrarily far into the future. If it's not in
 436          * the current generation, either we'll wrap before hitting it,
 437          * or it's in the past and has been handled already.
 438          *
 439          * If there's a wakeup before we wrap, arrange to be woken up by
 440          * the page boundary following it. Keep the tail boundary if
 441          * that's lower.
 442          */
 443         if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
 444                 limit = min(limit, round_up(wakeup, PAGE_SIZE));
 445 
 446         if (limit > head)
 447                 return limit;
 448 
 449         arm_spe_pmu_pad_buf(handle, handle->size);
 450 no_space:
 451         perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
 452         perf_aux_output_end(handle, 0);
 453         return 0;
 454 }
 455 
 456 static u64 arm_spe_pmu_next_off(struct perf_output_handle *handle)
 457 {
 458         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 459         struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
 460         u64 limit = __arm_spe_pmu_next_off(handle);
 461         u64 head = PERF_IDX2OFF(handle->head, buf);
 462 
 463         /*
 464          * If the head has come too close to the end of the buffer,
 465          * then pad to the end and recompute the limit.
 466          */
 467         if (limit && (limit - head < spe_pmu->max_record_sz)) {
 468                 arm_spe_pmu_pad_buf(handle, limit - head);
 469                 limit = __arm_spe_pmu_next_off(handle);
 470         }
 471 
 472         return limit;
 473 }
 474 
 475 static void arm_spe_perf_aux_output_begin(struct perf_output_handle *handle,
 476                                           struct perf_event *event)
 477 {
 478         u64 base, limit;
 479         struct arm_spe_pmu_buf *buf;
 480 
 481         /* Start a new aux session */
 482         buf = perf_aux_output_begin(handle, event);
 483         if (!buf) {
 484                 event->hw.state |= PERF_HES_STOPPED;
 485                 /*
 486                  * We still need to clear the limit pointer, since the
 487                  * profiler might only be disabled by virtue of a fault.
 488                  */
 489                 limit = 0;
 490                 goto out_write_limit;
 491         }
 492 
 493         limit = buf->snapshot ? arm_spe_pmu_next_snapshot_off(handle)
 494                               : arm_spe_pmu_next_off(handle);
 495         if (limit)
 496                 limit |= BIT(SYS_PMBLIMITR_EL1_E_SHIFT);
 497 
 498         limit += (u64)buf->base;
 499         base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf);
 500         write_sysreg_s(base, SYS_PMBPTR_EL1);
 501 
 502 out_write_limit:
 503         write_sysreg_s(limit, SYS_PMBLIMITR_EL1);
 504 }
 505 
 506 static void arm_spe_perf_aux_output_end(struct perf_output_handle *handle)
 507 {
 508         struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
 509         u64 offset, size;
 510 
 511         offset = read_sysreg_s(SYS_PMBPTR_EL1) - (u64)buf->base;
 512         size = offset - PERF_IDX2OFF(handle->head, buf);
 513 
 514         if (buf->snapshot)
 515                 handle->head = offset;
 516 
 517         perf_aux_output_end(handle, size);
 518 }
 519 
 520 static void arm_spe_pmu_disable_and_drain_local(void)
 521 {
 522         /* Disable profiling at EL0 and EL1 */
 523         write_sysreg_s(0, SYS_PMSCR_EL1);
 524         isb();
 525 
 526         /* Drain any buffered data */
 527         psb_csync();
 528         dsb(nsh);
 529 
 530         /* Disable the profiling buffer */
 531         write_sysreg_s(0, SYS_PMBLIMITR_EL1);
 532         isb();
 533 }
 534 
 535 /* IRQ handling */
 536 static enum arm_spe_pmu_buf_fault_action
 537 arm_spe_pmu_buf_get_fault_act(struct perf_output_handle *handle)
 538 {
 539         const char *err_str;
 540         u64 pmbsr;
 541         enum arm_spe_pmu_buf_fault_action ret;
 542 
 543         /*
 544          * Ensure new profiling data is visible to the CPU and any external
 545          * aborts have been resolved.
 546          */
 547         psb_csync();
 548         dsb(nsh);
 549 
 550         /* Ensure hardware updates to PMBPTR_EL1 are visible */
 551         isb();
 552 
 553         /* Service required? */
 554         pmbsr = read_sysreg_s(SYS_PMBSR_EL1);
 555         if (!(pmbsr & BIT(SYS_PMBSR_EL1_S_SHIFT)))
 556                 return SPE_PMU_BUF_FAULT_ACT_SPURIOUS;
 557 
 558         /*
 559          * If we've lost data, disable profiling and also set the PARTIAL
 560          * flag to indicate that the last record is corrupted.
 561          */
 562         if (pmbsr & BIT(SYS_PMBSR_EL1_DL_SHIFT))
 563                 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED |
 564                                              PERF_AUX_FLAG_PARTIAL);
 565 
 566         /* Report collisions to userspace so that it can up the period */
 567         if (pmbsr & BIT(SYS_PMBSR_EL1_COLL_SHIFT))
 568                 perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
 569 
 570         /* We only expect buffer management events */
 571         switch (pmbsr & (SYS_PMBSR_EL1_EC_MASK << SYS_PMBSR_EL1_EC_SHIFT)) {
 572         case SYS_PMBSR_EL1_EC_BUF:
 573                 /* Handled below */
 574                 break;
 575         case SYS_PMBSR_EL1_EC_FAULT_S1:
 576         case SYS_PMBSR_EL1_EC_FAULT_S2:
 577                 err_str = "Unexpected buffer fault";
 578                 goto out_err;
 579         default:
 580                 err_str = "Unknown error code";
 581                 goto out_err;
 582         }
 583 
 584         /* Buffer management event */
 585         switch (pmbsr &
 586                 (SYS_PMBSR_EL1_BUF_BSC_MASK << SYS_PMBSR_EL1_BUF_BSC_SHIFT)) {
 587         case SYS_PMBSR_EL1_BUF_BSC_FULL:
 588                 ret = SPE_PMU_BUF_FAULT_ACT_OK;
 589                 goto out_stop;
 590         default:
 591                 err_str = "Unknown buffer status code";
 592         }
 593 
 594 out_err:
 595         pr_err_ratelimited("%s on CPU %d [PMBSR=0x%016llx, PMBPTR=0x%016llx, PMBLIMITR=0x%016llx]\n",
 596                            err_str, smp_processor_id(), pmbsr,
 597                            read_sysreg_s(SYS_PMBPTR_EL1),
 598                            read_sysreg_s(SYS_PMBLIMITR_EL1));
 599         ret = SPE_PMU_BUF_FAULT_ACT_FATAL;
 600 
 601 out_stop:
 602         arm_spe_perf_aux_output_end(handle);
 603         return ret;
 604 }
 605 
 606 static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev)
 607 {
 608         struct perf_output_handle *handle = dev;
 609         struct perf_event *event = handle->event;
 610         enum arm_spe_pmu_buf_fault_action act;
 611 
 612         if (!perf_get_aux(handle))
 613                 return IRQ_NONE;
 614 
 615         act = arm_spe_pmu_buf_get_fault_act(handle);
 616         if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
 617                 return IRQ_NONE;
 618 
 619         /*
 620          * Ensure perf callbacks have completed, which may disable the
 621          * profiling buffer in response to a TRUNCATION flag.
 622          */
 623         irq_work_run();
 624 
 625         switch (act) {
 626         case SPE_PMU_BUF_FAULT_ACT_FATAL:
 627                 /*
 628                  * If a fatal exception occurred then leaving the profiling
 629                  * buffer enabled is a recipe waiting to happen. Since
 630                  * fatal faults don't always imply truncation, make sure
 631                  * that the profiling buffer is disabled explicitly before
 632                  * clearing the syndrome register.
 633                  */
 634                 arm_spe_pmu_disable_and_drain_local();
 635                 break;
 636         case SPE_PMU_BUF_FAULT_ACT_OK:
 637                 /*
 638                  * We handled the fault (the buffer was full), so resume
 639                  * profiling as long as we didn't detect truncation.
 640                  * PMBPTR might be misaligned, but we'll burn that bridge
 641                  * when we get to it.
 642                  */
 643                 if (!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)) {
 644                         arm_spe_perf_aux_output_begin(handle, event);
 645                         isb();
 646                 }
 647                 break;
 648         case SPE_PMU_BUF_FAULT_ACT_SPURIOUS:
 649                 /* We've seen you before, but GCC has the memory of a sieve. */
 650                 break;
 651         }
 652 
 653         /* The buffer pointers are now sane, so resume profiling. */
 654         write_sysreg_s(0, SYS_PMBSR_EL1);
 655         return IRQ_HANDLED;
 656 }
 657 
 658 /* Perf callbacks */
 659 static int arm_spe_pmu_event_init(struct perf_event *event)
 660 {
 661         u64 reg;
 662         struct perf_event_attr *attr = &event->attr;
 663         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 664 
 665         /* This is, of course, deeply driver-specific */
 666         if (attr->type != event->pmu->type)
 667                 return -ENOENT;
 668 
 669         if (event->cpu >= 0 &&
 670             !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus))
 671                 return -ENOENT;
 672 
 673         if (arm_spe_event_to_pmsevfr(event) & SYS_PMSEVFR_EL1_RES0)
 674                 return -EOPNOTSUPP;
 675 
 676         if (attr->exclude_idle)
 677                 return -EOPNOTSUPP;
 678 
 679         /*
 680          * Feedback-directed frequency throttling doesn't work when we
 681          * have a buffer of samples. We'd need to manually count the
 682          * samples in the buffer when it fills up and adjust the event
 683          * count to reflect that. Instead, just force the user to specify
 684          * a sample period.
 685          */
 686         if (attr->freq)
 687                 return -EINVAL;
 688 
 689         reg = arm_spe_event_to_pmsfcr(event);
 690         if ((reg & BIT(SYS_PMSFCR_EL1_FE_SHIFT)) &&
 691             !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT))
 692                 return -EOPNOTSUPP;
 693 
 694         if ((reg & BIT(SYS_PMSFCR_EL1_FT_SHIFT)) &&
 695             !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP))
 696                 return -EOPNOTSUPP;
 697 
 698         if ((reg & BIT(SYS_PMSFCR_EL1_FL_SHIFT)) &&
 699             !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
 700                 return -EOPNOTSUPP;
 701 
 702         reg = arm_spe_event_to_pmscr(event);
 703         if (!capable(CAP_SYS_ADMIN) &&
 704             (reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) |
 705                     BIT(SYS_PMSCR_EL1_CX_SHIFT) |
 706                     BIT(SYS_PMSCR_EL1_PCT_SHIFT))))
 707                 return -EACCES;
 708 
 709         return 0;
 710 }
 711 
 712 static void arm_spe_pmu_start(struct perf_event *event, int flags)
 713 {
 714         u64 reg;
 715         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 716         struct hw_perf_event *hwc = &event->hw;
 717         struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
 718 
 719         hwc->state = 0;
 720         arm_spe_perf_aux_output_begin(handle, event);
 721         if (hwc->state)
 722                 return;
 723 
 724         reg = arm_spe_event_to_pmsfcr(event);
 725         write_sysreg_s(reg, SYS_PMSFCR_EL1);
 726 
 727         reg = arm_spe_event_to_pmsevfr(event);
 728         write_sysreg_s(reg, SYS_PMSEVFR_EL1);
 729 
 730         reg = arm_spe_event_to_pmslatfr(event);
 731         write_sysreg_s(reg, SYS_PMSLATFR_EL1);
 732 
 733         if (flags & PERF_EF_RELOAD) {
 734                 reg = arm_spe_event_to_pmsirr(event);
 735                 write_sysreg_s(reg, SYS_PMSIRR_EL1);
 736                 isb();
 737                 reg = local64_read(&hwc->period_left);
 738                 write_sysreg_s(reg, SYS_PMSICR_EL1);
 739         }
 740 
 741         reg = arm_spe_event_to_pmscr(event);
 742         isb();
 743         write_sysreg_s(reg, SYS_PMSCR_EL1);
 744 }
 745 
 746 static void arm_spe_pmu_stop(struct perf_event *event, int flags)
 747 {
 748         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 749         struct hw_perf_event *hwc = &event->hw;
 750         struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
 751 
 752         /* If we're already stopped, then nothing to do */
 753         if (hwc->state & PERF_HES_STOPPED)
 754                 return;
 755 
 756         /* Stop all trace generation */
 757         arm_spe_pmu_disable_and_drain_local();
 758 
 759         if (flags & PERF_EF_UPDATE) {
 760                 /*
 761                  * If there's a fault pending then ensure we contain it
 762                  * to this buffer, since we might be on the context-switch
 763                  * path.
 764                  */
 765                 if (perf_get_aux(handle)) {
 766                         enum arm_spe_pmu_buf_fault_action act;
 767 
 768                         act = arm_spe_pmu_buf_get_fault_act(handle);
 769                         if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
 770                                 arm_spe_perf_aux_output_end(handle);
 771                         else
 772                                 write_sysreg_s(0, SYS_PMBSR_EL1);
 773                 }
 774 
 775                 /*
 776                  * This may also contain ECOUNT, but nobody else should
 777                  * be looking at period_left, since we forbid frequency
 778                  * based sampling.
 779                  */
 780                 local64_set(&hwc->period_left, read_sysreg_s(SYS_PMSICR_EL1));
 781                 hwc->state |= PERF_HES_UPTODATE;
 782         }
 783 
 784         hwc->state |= PERF_HES_STOPPED;
 785 }
 786 
 787 static int arm_spe_pmu_add(struct perf_event *event, int flags)
 788 {
 789         int ret = 0;
 790         struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
 791         struct hw_perf_event *hwc = &event->hw;
 792         int cpu = event->cpu == -1 ? smp_processor_id() : event->cpu;
 793 
 794         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
 795                 return -ENOENT;
 796 
 797         hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
 798 
 799         if (flags & PERF_EF_START) {
 800                 arm_spe_pmu_start(event, PERF_EF_RELOAD);
 801                 if (hwc->state & PERF_HES_STOPPED)
 802                         ret = -EINVAL;
 803         }
 804 
 805         return ret;
 806 }
 807 
 808 static void arm_spe_pmu_del(struct perf_event *event, int flags)
 809 {
 810         arm_spe_pmu_stop(event, PERF_EF_UPDATE);
 811 }
 812 
 813 static void arm_spe_pmu_read(struct perf_event *event)
 814 {
 815 }
 816 
 817 static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
 818                                    int nr_pages, bool snapshot)
 819 {
 820         int i, cpu = event->cpu;
 821         struct page **pglist;
 822         struct arm_spe_pmu_buf *buf;
 823 
 824         /* We need at least two pages for this to work. */
 825         if (nr_pages < 2)
 826                 return NULL;
 827 
 828         /*
 829          * We require an even number of pages for snapshot mode, so that
 830          * we can effectively treat the buffer as consisting of two equal
 831          * parts and give userspace a fighting chance of getting some
 832          * useful data out of it.
 833          */
 834         if (!nr_pages || (snapshot && (nr_pages & 1)))
 835                 return NULL;
 836 
 837         if (cpu == -1)
 838                 cpu = raw_smp_processor_id();
 839 
 840         buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, cpu_to_node(cpu));
 841         if (!buf)
 842                 return NULL;
 843 
 844         pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
 845         if (!pglist)
 846                 goto out_free_buf;
 847 
 848         for (i = 0; i < nr_pages; ++i)
 849                 pglist[i] = virt_to_page(pages[i]);
 850 
 851         buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
 852         if (!buf->base)
 853                 goto out_free_pglist;
 854 
 855         buf->nr_pages   = nr_pages;
 856         buf->snapshot   = snapshot;
 857 
 858         kfree(pglist);
 859         return buf;
 860 
 861 out_free_pglist:
 862         kfree(pglist);
 863 out_free_buf:
 864         kfree(buf);
 865         return NULL;
 866 }
 867 
 868 static void arm_spe_pmu_free_aux(void *aux)
 869 {
 870         struct arm_spe_pmu_buf *buf = aux;
 871 
 872         vunmap(buf->base);
 873         kfree(buf);
 874 }
 875 
 876 /* Initialisation and teardown functions */
 877 static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
 878 {
 879         static atomic_t pmu_idx = ATOMIC_INIT(-1);
 880 
 881         int idx;
 882         char *name;
 883         struct device *dev = &spe_pmu->pdev->dev;
 884 
 885         spe_pmu->pmu = (struct pmu) {
 886                 .module = THIS_MODULE,
 887                 .capabilities   = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
 888                 .attr_groups    = arm_spe_pmu_attr_groups,
 889                 /*
 890                  * We hitch a ride on the software context here, so that
 891                  * we can support per-task profiling (which is not possible
 892                  * with the invalid context as it doesn't get sched callbacks).
 893                  * This requires that userspace either uses a dummy event for
 894                  * perf_event_open, since the aux buffer is not setup until
 895                  * a subsequent mmap, or creates the profiling event in a
 896                  * disabled state and explicitly PERF_EVENT_IOC_ENABLEs it
 897                  * once the buffer has been created.
 898                  */
 899                 .task_ctx_nr    = perf_sw_context,
 900                 .event_init     = arm_spe_pmu_event_init,
 901                 .add            = arm_spe_pmu_add,
 902                 .del            = arm_spe_pmu_del,
 903                 .start          = arm_spe_pmu_start,
 904                 .stop           = arm_spe_pmu_stop,
 905                 .read           = arm_spe_pmu_read,
 906                 .setup_aux      = arm_spe_pmu_setup_aux,
 907                 .free_aux       = arm_spe_pmu_free_aux,
 908         };
 909 
 910         idx = atomic_inc_return(&pmu_idx);
 911         name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx);
 912         if (!name) {
 913                 dev_err(dev, "failed to allocate name for pmu %d\n", idx);
 914                 return -ENOMEM;
 915         }
 916 
 917         return perf_pmu_register(&spe_pmu->pmu, name, -1);
 918 }
 919 
 920 static void arm_spe_pmu_perf_destroy(struct arm_spe_pmu *spe_pmu)
 921 {
 922         perf_pmu_unregister(&spe_pmu->pmu);
 923 }
 924 
 925 static void __arm_spe_pmu_dev_probe(void *info)
 926 {
 927         int fld;
 928         u64 reg;
 929         struct arm_spe_pmu *spe_pmu = info;
 930         struct device *dev = &spe_pmu->pdev->dev;
 931 
 932         fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64DFR0_EL1),
 933                                                    ID_AA64DFR0_PMSVER_SHIFT);
 934         if (!fld) {
 935                 dev_err(dev,
 936                         "unsupported ID_AA64DFR0_EL1.PMSVer [%d] on CPU %d\n",
 937                         fld, smp_processor_id());
 938                 return;
 939         }
 940 
 941         /* Read PMBIDR first to determine whether or not we have access */
 942         reg = read_sysreg_s(SYS_PMBIDR_EL1);
 943         if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT)) {
 944                 dev_err(dev,
 945                         "profiling buffer owned by higher exception level\n");
 946                 return;
 947         }
 948 
 949         /* Minimum alignment. If it's out-of-range, then fail the probe */
 950         fld = reg >> SYS_PMBIDR_EL1_ALIGN_SHIFT & SYS_PMBIDR_EL1_ALIGN_MASK;
 951         spe_pmu->align = 1 << fld;
 952         if (spe_pmu->align > SZ_2K) {
 953                 dev_err(dev, "unsupported PMBIDR.Align [%d] on CPU %d\n",
 954                         fld, smp_processor_id());
 955                 return;
 956         }
 957 
 958         /* It's now safe to read PMSIDR and figure out what we've got */
 959         reg = read_sysreg_s(SYS_PMSIDR_EL1);
 960         if (reg & BIT(SYS_PMSIDR_EL1_FE_SHIFT))
 961                 spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT;
 962 
 963         if (reg & BIT(SYS_PMSIDR_EL1_FT_SHIFT))
 964                 spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP;
 965 
 966         if (reg & BIT(SYS_PMSIDR_EL1_FL_SHIFT))
 967                 spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT;
 968 
 969         if (reg & BIT(SYS_PMSIDR_EL1_ARCHINST_SHIFT))
 970                 spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST;
 971 
 972         if (reg & BIT(SYS_PMSIDR_EL1_LDS_SHIFT))
 973                 spe_pmu->features |= SPE_PMU_FEAT_LDS;
 974 
 975         if (reg & BIT(SYS_PMSIDR_EL1_ERND_SHIFT))
 976                 spe_pmu->features |= SPE_PMU_FEAT_ERND;
 977 
 978         /* This field has a spaced out encoding, so just use a look-up */
 979         fld = reg >> SYS_PMSIDR_EL1_INTERVAL_SHIFT & SYS_PMSIDR_EL1_INTERVAL_MASK;
 980         switch (fld) {
 981         case 0:
 982                 spe_pmu->min_period = 256;
 983                 break;
 984         case 2:
 985                 spe_pmu->min_period = 512;
 986                 break;
 987         case 3:
 988                 spe_pmu->min_period = 768;
 989                 break;
 990         case 4:
 991                 spe_pmu->min_period = 1024;
 992                 break;
 993         case 5:
 994                 spe_pmu->min_period = 1536;
 995                 break;
 996         case 6:
 997                 spe_pmu->min_period = 2048;
 998                 break;
 999         case 7:
1000                 spe_pmu->min_period = 3072;
1001                 break;
1002         default:
1003                 dev_warn(dev, "unknown PMSIDR_EL1.Interval [%d]; assuming 8\n",
1004                          fld);
1005                 /* Fallthrough */
1006         case 8:
1007                 spe_pmu->min_period = 4096;
1008         }
1009 
1010         /* Maximum record size. If it's out-of-range, then fail the probe */
1011         fld = reg >> SYS_PMSIDR_EL1_MAXSIZE_SHIFT & SYS_PMSIDR_EL1_MAXSIZE_MASK;
1012         spe_pmu->max_record_sz = 1 << fld;
1013         if (spe_pmu->max_record_sz > SZ_2K || spe_pmu->max_record_sz < 16) {
1014                 dev_err(dev, "unsupported PMSIDR_EL1.MaxSize [%d] on CPU %d\n",
1015                         fld, smp_processor_id());
1016                 return;
1017         }
1018 
1019         fld = reg >> SYS_PMSIDR_EL1_COUNTSIZE_SHIFT & SYS_PMSIDR_EL1_COUNTSIZE_MASK;
1020         switch (fld) {
1021         default:
1022                 dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n",
1023                          fld);
1024                 /* Fallthrough */
1025         case 2:
1026                 spe_pmu->counter_sz = 12;
1027         }
1028 
1029         dev_info(dev,
1030                  "probed for CPUs %*pbl [max_record_sz %u, align %u, features 0x%llx]\n",
1031                  cpumask_pr_args(&spe_pmu->supported_cpus),
1032                  spe_pmu->max_record_sz, spe_pmu->align, spe_pmu->features);
1033 
1034         spe_pmu->features |= SPE_PMU_FEAT_DEV_PROBED;
1035         return;
1036 }
1037 
1038 static void __arm_spe_pmu_reset_local(void)
1039 {
1040         /*
1041          * This is probably overkill, as we have no idea where we're
1042          * draining any buffered data to...
1043          */
1044         arm_spe_pmu_disable_and_drain_local();
1045 
1046         /* Reset the buffer base pointer */
1047         write_sysreg_s(0, SYS_PMBPTR_EL1);
1048         isb();
1049 
1050         /* Clear any pending management interrupts */
1051         write_sysreg_s(0, SYS_PMBSR_EL1);
1052         isb();
1053 }
1054 
1055 static void __arm_spe_pmu_setup_one(void *info)
1056 {
1057         struct arm_spe_pmu *spe_pmu = info;
1058 
1059         __arm_spe_pmu_reset_local();
1060         enable_percpu_irq(spe_pmu->irq, IRQ_TYPE_NONE);
1061 }
1062 
1063 static void __arm_spe_pmu_stop_one(void *info)
1064 {
1065         struct arm_spe_pmu *spe_pmu = info;
1066 
1067         disable_percpu_irq(spe_pmu->irq);
1068         __arm_spe_pmu_reset_local();
1069 }
1070 
1071 static int arm_spe_pmu_cpu_startup(unsigned int cpu, struct hlist_node *node)
1072 {
1073         struct arm_spe_pmu *spe_pmu;
1074 
1075         spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1076         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1077                 return 0;
1078 
1079         __arm_spe_pmu_setup_one(spe_pmu);
1080         return 0;
1081 }
1082 
1083 static int arm_spe_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
1084 {
1085         struct arm_spe_pmu *spe_pmu;
1086 
1087         spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1088         if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1089                 return 0;
1090 
1091         __arm_spe_pmu_stop_one(spe_pmu);
1092         return 0;
1093 }
1094 
1095 static int arm_spe_pmu_dev_init(struct arm_spe_pmu *spe_pmu)
1096 {
1097         int ret;
1098         cpumask_t *mask = &spe_pmu->supported_cpus;
1099 
1100         /* Make sure we probe the hardware on a relevant CPU */
1101         ret = smp_call_function_any(mask,  __arm_spe_pmu_dev_probe, spe_pmu, 1);
1102         if (ret || !(spe_pmu->features & SPE_PMU_FEAT_DEV_PROBED))
1103                 return -ENXIO;
1104 
1105         /* Request our PPIs (note that the IRQ is still disabled) */
1106         ret = request_percpu_irq(spe_pmu->irq, arm_spe_pmu_irq_handler, DRVNAME,
1107                                  spe_pmu->handle);
1108         if (ret)
1109                 return ret;
1110 
1111         /*
1112          * Register our hotplug notifier now so we don't miss any events.
1113          * This will enable the IRQ for any supported CPUs that are already
1114          * up.
1115          */
1116         ret = cpuhp_state_add_instance(arm_spe_pmu_online,
1117                                        &spe_pmu->hotplug_node);
1118         if (ret)
1119                 free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1120 
1121         return ret;
1122 }
1123 
1124 static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu)
1125 {
1126         cpuhp_state_remove_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node);
1127         free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1128 }
1129 
1130 /* Driver and device probing */
1131 static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu)
1132 {
1133         struct platform_device *pdev = spe_pmu->pdev;
1134         int irq = platform_get_irq(pdev, 0);
1135 
1136         if (irq < 0) {
1137                 dev_err(&pdev->dev, "failed to get IRQ (%d)\n", irq);
1138                 return -ENXIO;
1139         }
1140 
1141         if (!irq_is_percpu(irq)) {
1142                 dev_err(&pdev->dev, "expected PPI but got SPI (%d)\n", irq);
1143                 return -EINVAL;
1144         }
1145 
1146         if (irq_get_percpu_devid_partition(irq, &spe_pmu->supported_cpus)) {
1147                 dev_err(&pdev->dev, "failed to get PPI partition (%d)\n", irq);
1148                 return -EINVAL;
1149         }
1150 
1151         spe_pmu->irq = irq;
1152         return 0;
1153 }
1154 
1155 static const struct of_device_id arm_spe_pmu_of_match[] = {
1156         { .compatible = "arm,statistical-profiling-extension-v1", .data = (void *)1 },
1157         { /* Sentinel */ },
1158 };
1159 MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
1160 
1161 static const struct platform_device_id arm_spe_match[] = {
1162         { ARMV8_SPE_PDEV_NAME, 0},
1163         { }
1164 };
1165 MODULE_DEVICE_TABLE(platform, arm_spe_match);
1166 
1167 static int arm_spe_pmu_device_probe(struct platform_device *pdev)
1168 {
1169         int ret;
1170         struct arm_spe_pmu *spe_pmu;
1171         struct device *dev = &pdev->dev;
1172 
1173         /*
1174          * If kernelspace is unmapped when running at EL0, then the SPE
1175          * buffer will fault and prematurely terminate the AUX session.
1176          */
1177         if (arm64_kernel_unmapped_at_el0()) {
1178                 dev_warn_once(dev, "profiling buffer inaccessible. Try passing \"kpti=off\" on the kernel command line\n");
1179                 return -EPERM;
1180         }
1181 
1182         spe_pmu = devm_kzalloc(dev, sizeof(*spe_pmu), GFP_KERNEL);
1183         if (!spe_pmu) {
1184                 dev_err(dev, "failed to allocate spe_pmu\n");
1185                 return -ENOMEM;
1186         }
1187 
1188         spe_pmu->handle = alloc_percpu(typeof(*spe_pmu->handle));
1189         if (!spe_pmu->handle)
1190                 return -ENOMEM;
1191 
1192         spe_pmu->pdev = pdev;
1193         platform_set_drvdata(pdev, spe_pmu);
1194 
1195         ret = arm_spe_pmu_irq_probe(spe_pmu);
1196         if (ret)
1197                 goto out_free_handle;
1198 
1199         ret = arm_spe_pmu_dev_init(spe_pmu);
1200         if (ret)
1201                 goto out_free_handle;
1202 
1203         ret = arm_spe_pmu_perf_init(spe_pmu);
1204         if (ret)
1205                 goto out_teardown_dev;
1206 
1207         return 0;
1208 
1209 out_teardown_dev:
1210         arm_spe_pmu_dev_teardown(spe_pmu);
1211 out_free_handle:
1212         free_percpu(spe_pmu->handle);
1213         return ret;
1214 }
1215 
1216 static int arm_spe_pmu_device_remove(struct platform_device *pdev)
1217 {
1218         struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
1219 
1220         arm_spe_pmu_perf_destroy(spe_pmu);
1221         arm_spe_pmu_dev_teardown(spe_pmu);
1222         free_percpu(spe_pmu->handle);
1223         return 0;
1224 }
1225 
1226 static struct platform_driver arm_spe_pmu_driver = {
1227         .id_table = arm_spe_match,
1228         .driver = {
1229                 .name           = DRVNAME,
1230                 .of_match_table = of_match_ptr(arm_spe_pmu_of_match),
1231         },
1232         .probe  = arm_spe_pmu_device_probe,
1233         .remove = arm_spe_pmu_device_remove,
1234 };
1235 
1236 static int __init arm_spe_pmu_init(void)
1237 {
1238         int ret;
1239 
1240         ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
1241                                       arm_spe_pmu_cpu_startup,
1242                                       arm_spe_pmu_cpu_teardown);
1243         if (ret < 0)
1244                 return ret;
1245         arm_spe_pmu_online = ret;
1246 
1247         ret = platform_driver_register(&arm_spe_pmu_driver);
1248         if (ret)
1249                 cpuhp_remove_multi_state(arm_spe_pmu_online);
1250 
1251         return ret;
1252 }
1253 
1254 static void __exit arm_spe_pmu_exit(void)
1255 {
1256         platform_driver_unregister(&arm_spe_pmu_driver);
1257         cpuhp_remove_multi_state(arm_spe_pmu_online);
1258 }
1259 
1260 module_init(arm_spe_pmu_init);
1261 module_exit(arm_spe_pmu_exit);
1262 
1263 MODULE_DESCRIPTION("Perf driver for the ARMv8.2 Statistical Profiling Extension");
1264 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
1265 MODULE_LICENSE("GPL v2");
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root/drivers/perf/arm_spe_pmu.c

DEFINITIONS
