arch/powerpc/perf/hv-gpci.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Hypervisor supplied "gpci" ("get performance counter info") performance
   4  * counter support
   5  *
   6  * Author: Cody P Schafer <cody@linux.vnet.ibm.com>
   7  * Copyright 2014 IBM Corporation.
   8  */
   9
  10 #define pr_fmt(fmt) "hv-gpci: " fmt
  11
  12 #include <linux/init.h>
  13 #include <linux/perf_event.h>
  14 #include <asm/firmware.h>
  15 #include <asm/hvcall.h>
  16 #include <asm/io.h>
  17
  18 #include "hv-gpci.h"
  19 #include "hv-common.h"
  20
  21 /*
  22  * Example usage:
  23  *  perf stat -e 'hv_gpci/counter_info_version=3,offset=0,length=8,
  24  *                secondary_index=0,starting_index=0xffffffff,request=0x10/' ...
  25  */
  26
  27 /* u32 */
  28 EVENT_DEFINE_RANGE_FORMAT(request, config, 0, 31);
  29 /* u32 */
  30 /*
  31  * Note that starting_index, phys_processor_idx, sibling_part_id,
  32  * hw_chip_id, partition_id all refer to the same bit range. They
  33  * are basically aliases for the starting_index. The specific alias
  34  * used depends on the event. See REQUEST_IDX_KIND in hv-gpci-requests.h
  35  */
  36 EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 32, 63);
  37 EVENT_DEFINE_RANGE_FORMAT_LITE(phys_processor_idx, config, 32, 63);
  38 EVENT_DEFINE_RANGE_FORMAT_LITE(sibling_part_id, config, 32, 63);
  39 EVENT_DEFINE_RANGE_FORMAT_LITE(hw_chip_id, config, 32, 63);
  40 EVENT_DEFINE_RANGE_FORMAT_LITE(partition_id, config, 32, 63);
  41
  42 /* u16 */
  43 EVENT_DEFINE_RANGE_FORMAT(secondary_index, config1, 0, 15);
  44 /* u8 */
  45 EVENT_DEFINE_RANGE_FORMAT(counter_info_version, config1, 16, 23);
  46 /* u8, bytes of data (1-8) */
  47 EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31);
  48 /* u32, byte offset */
  49 EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63);
  50
  51 static cpumask_t hv_gpci_cpumask;
  52
  53 static struct attribute *format_attrs[] = {
  54         &format_attr_request.attr,
  55         &format_attr_starting_index.attr,
  56         &format_attr_phys_processor_idx.attr,
  57         &format_attr_sibling_part_id.attr,
  58         &format_attr_hw_chip_id.attr,
  59         &format_attr_partition_id.attr,
  60         &format_attr_secondary_index.attr,
  61         &format_attr_counter_info_version.attr,
  62
  63         &format_attr_offset.attr,
  64         &format_attr_length.attr,
  65         NULL,
  66 };
  67
  68 static const struct attribute_group format_group = {
  69         .name = "format",
  70         .attrs = format_attrs,
  71 };
  72
  73 static struct attribute_group event_group = {
  74         .name  = "events",
  75         /* .attrs is set in init */
  76 };
  77
  78 #define HV_CAPS_ATTR(_name, _format)                            \
  79 static ssize_t _name##_show(struct device *dev,                 \
  80                             struct device_attribute *attr,      \
  81                             char *page)                         \
  82 {                                                               \
  83         struct hv_perf_caps caps;                               \
  84         unsigned long hret = hv_perf_caps_get(&caps);           \
  85         if (hret)                                               \
  86                 return -EIO;                                    \
  87                                                                 \
  88         return sprintf(page, _format, caps._name);              \
  89 }                                                               \
  90 static struct device_attribute hv_caps_attr_##_name = __ATTR_RO(_name)
  91
  92 static ssize_t kernel_version_show(struct device *dev,
  93                                    struct device_attribute *attr,
  94                                    char *page)
  95 {
  96         return sprintf(page, "0x%x\n", COUNTER_INFO_VERSION_CURRENT);
  97 }
  98
  99 static ssize_t cpumask_show(struct device *dev,
 100                             struct device_attribute *attr, char *buf)
 101 {
 102         return cpumap_print_to_pagebuf(true, buf, &hv_gpci_cpumask);
 103 }
 104
 105 static DEVICE_ATTR_RO(kernel_version);
 106 static DEVICE_ATTR_RO(cpumask);
 107
 108 HV_CAPS_ATTR(version, "0x%x\n");
 109 HV_CAPS_ATTR(ga, "%d\n");
 110 HV_CAPS_ATTR(expanded, "%d\n");
 111 HV_CAPS_ATTR(lab, "%d\n");
 112 HV_CAPS_ATTR(collect_privileged, "%d\n");
 113
 114 static struct attribute *interface_attrs[] = {
 115         &dev_attr_kernel_version.attr,
 116         &hv_caps_attr_version.attr,
 117         &hv_caps_attr_ga.attr,
 118         &hv_caps_attr_expanded.attr,
 119         &hv_caps_attr_lab.attr,
 120         &hv_caps_attr_collect_privileged.attr,
 121         NULL,
 122 };
 123
 124 static struct attribute *cpumask_attrs[] = {
 125         &dev_attr_cpumask.attr,
 126         NULL,
 127 };
 128
 129 static const struct attribute_group cpumask_attr_group = {
 130         .attrs = cpumask_attrs,
 131 };
 132
 133 static const struct attribute_group interface_group = {
 134         .name = "interface",
 135         .attrs = interface_attrs,
 136 };
 137
 138 static const struct attribute_group *attr_groups[] = {
 139         &format_group,
 140         &event_group,
 141         &interface_group,
 142         &cpumask_attr_group,
 143         NULL,
 144 };
 145
 146 static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
 147
 148 static unsigned long single_gpci_request(u32 req, u32 starting_index,
 149                 u16 secondary_index, u8 version_in, u32 offset, u8 length,
 150                 u64 *value)
 151 {
 152         unsigned long ret;
 153         size_t i;
 154         u64 count;
 155         struct hv_gpci_request_buffer *arg;
 156
 157         arg = (void *)get_cpu_var(hv_gpci_reqb);
 158         memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
 159
 160         arg->params.counter_request = cpu_to_be32(req);
 161         arg->params.starting_index = cpu_to_be32(starting_index);
 162         arg->params.secondary_index = cpu_to_be16(secondary_index);
 163         arg->params.counter_info_version_in = version_in;
 164
 165         ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
 166                         virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
 167         if (ret) {
 168                 pr_devel("hcall failed: 0x%lx\n", ret);
 169                 goto out;
 170         }
 171
 172         /*
 173          * we verify offset and length are within the zeroed buffer at event
 174          * init.
 175          */
 176         count = 0;
 177         for (i = offset; i < offset + length; i++)
 178                 count |= (u64)(arg->bytes[i]) << ((length - 1 - (i - offset)) * 8);
 179
 180         *value = count;
 181 out:
 182         put_cpu_var(hv_gpci_reqb);
 183         return ret;
 184 }
 185
 186 static u64 h_gpci_get_value(struct perf_event *event)
 187 {
 188         u64 count;
 189         unsigned long ret = single_gpci_request(event_get_request(event),
 190                                         event_get_starting_index(event),
 191                                         event_get_secondary_index(event),
 192                                         event_get_counter_info_version(event),
 193                                         event_get_offset(event),
 194                                         event_get_length(event),
 195                                         &count);
 196         if (ret)
 197                 return 0;
 198         return count;
 199 }
 200
 201 static void h_gpci_event_update(struct perf_event *event)
 202 {
 203         s64 prev;
 204         u64 now = h_gpci_get_value(event);
 205         prev = local64_xchg(&event->hw.prev_count, now);
 206         local64_add(now - prev, &event->count);
 207 }
 208
 209 static void h_gpci_event_start(struct perf_event *event, int flags)
 210 {
 211         local64_set(&event->hw.prev_count, h_gpci_get_value(event));
 212 }
 213
 214 static void h_gpci_event_stop(struct perf_event *event, int flags)
 215 {
 216         h_gpci_event_update(event);
 217 }
 218
 219 static int h_gpci_event_add(struct perf_event *event, int flags)
 220 {
 221         if (flags & PERF_EF_START)
 222                 h_gpci_event_start(event, flags);
 223
 224         return 0;
 225 }
 226
 227 static int h_gpci_event_init(struct perf_event *event)
 228 {
 229         u64 count;
 230         u8 length;
 231
 232         /* Not our event */
 233         if (event->attr.type != event->pmu->type)
 234                 return -ENOENT;
 235
 236         /* config2 is unused */
 237         if (event->attr.config2) {
 238                 pr_devel("config2 set when reserved\n");
 239                 return -EINVAL;
 240         }
 241
 242         /* no branch sampling */
 243         if (has_branch_stack(event))
 244                 return -EOPNOTSUPP;
 245
 246         length = event_get_length(event);
 247         if (length < 1 || length > 8) {
 248                 pr_devel("length invalid\n");
 249                 return -EINVAL;
 250         }
 251
 252         /* last byte within the buffer? */
 253         if ((event_get_offset(event) + length) > HGPCI_MAX_DATA_BYTES) {
 254                 pr_devel("request outside of buffer: %zu > %zu\n",
 255                                 (size_t)event_get_offset(event) + length,
 256                                 HGPCI_MAX_DATA_BYTES);
 257                 return -EINVAL;
 258         }
 259
 260         /* check if the request works... */
 261         if (single_gpci_request(event_get_request(event),
 262                                 event_get_starting_index(event),
 263                                 event_get_secondary_index(event),
 264                                 event_get_counter_info_version(event),
 265                                 event_get_offset(event),
 266                                 length,
 267                                 &count)) {
 268                 pr_devel("gpci hcall failed\n");
 269                 return -EINVAL;
 270         }
 271
 272         return 0;
 273 }
 274
 275 static struct pmu h_gpci_pmu = {
 276         .task_ctx_nr = perf_invalid_context,
 277
 278         .name = "hv_gpci",
 279         .attr_groups = attr_groups,
 280         .event_init  = h_gpci_event_init,
 281         .add         = h_gpci_event_add,
 282         .del         = h_gpci_event_stop,
 283         .start       = h_gpci_event_start,
 284         .stop        = h_gpci_event_stop,
 285         .read        = h_gpci_event_update,
 286         .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
 287 };
 288
 289 static int ppc_hv_gpci_cpu_online(unsigned int cpu)
 290 {
 291         if (cpumask_empty(&hv_gpci_cpumask))
 292                 cpumask_set_cpu(cpu, &hv_gpci_cpumask);
 293
 294         return 0;
 295 }
 296
 297 static int ppc_hv_gpci_cpu_offline(unsigned int cpu)
 298 {
 299         int target;
 300
 301         /* Check if exiting cpu is used for collecting gpci events */
 302         if (!cpumask_test_and_clear_cpu(cpu, &hv_gpci_cpumask))
 303                 return 0;
 304
 305         /* Find a new cpu to collect gpci events */
 306         target = cpumask_last(cpu_active_mask);
 307
 308         if (target < 0 || target >= nr_cpu_ids) {
 309                 pr_err("hv_gpci: CPU hotplug init failed\n");
 310                 return -1;
 311         }
 312
 313         /* Migrate gpci events to the new target */
 314         cpumask_set_cpu(target, &hv_gpci_cpumask);
 315         perf_pmu_migrate_context(&h_gpci_pmu, cpu, target);
 316
 317         return 0;
 318 }
 319
 320 static int hv_gpci_cpu_hotplug_init(void)
 321 {
 322         return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
 323                           "perf/powerpc/hv_gcpi:online",
 324                           ppc_hv_gpci_cpu_online,
 325                           ppc_hv_gpci_cpu_offline);
 326 }
 327
 328 static int hv_gpci_init(void)
 329 {
 330         int r;
 331         unsigned long hret;
 332         struct hv_perf_caps caps;
 333         struct hv_gpci_request_buffer *arg;
 334
 335         hv_gpci_assert_offsets_correct();
 336
 337         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 338                 pr_debug("not a virtualized system, not enabling\n");
 339                 return -ENODEV;
 340         }
 341
 342         hret = hv_perf_caps_get(&caps);
 343         if (hret) {
 344                 pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
 345                                 hret);
 346                 return -ENODEV;
 347         }
 348
 349         /* init cpuhotplug */
 350         r = hv_gpci_cpu_hotplug_init();
 351         if (r)
 352                 return r;
 353
 354         /* sampling not supported */
 355         h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 356
 357         arg = (void *)get_cpu_var(hv_gpci_reqb);
 358         memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
 359
 360         /*
 361          * hcall H_GET_PERF_COUNTER_INFO populates the output
 362          * counter_info_version value based on the system hypervisor.
 363          * Pass the counter request 0x10 corresponds to request type
 364          * 'Dispatch_timebase_by_processor', to get the supported
 365          * counter_info_version.
 366          */
 367         arg->params.counter_request = cpu_to_be32(0x10);
 368
 369         r = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
 370                         virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
 371         if (r) {
 372                 pr_devel("hcall failed, can't get supported counter_info_version: 0x%x\n", r);
 373                 arg->params.counter_info_version_out = 0x8;
 374         }
 375
 376         /*
 377          * Use counter_info_version_out value to assign
 378          * required hv-gpci event list.
 379          */
 380         if (arg->params.counter_info_version_out >= 0x8)
 381                 event_group.attrs = hv_gpci_event_attrs;
 382         else
 383                 event_group.attrs = hv_gpci_event_attrs_v6;
 384
 385         put_cpu_var(hv_gpci_reqb);
 386
 387         r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
 388         if (r)
 389                 return r;
 390
 391         return 0;
 392 }
 393
 394 device_initcall(hv_gpci_init);