arch/powerpc/perf/hv-24x7.c

   1 /*
   2  * Hypervisor supplied "24x7" performance counter support
   3  *
   4  * Author: Cody P Schafer <cody@linux.vnet.ibm.com>
   5  * Copyright 2014 IBM Corporation.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #define pr_fmt(fmt) "hv-24x7: " fmt
  14
  15 #include <linux/perf_event.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <asm/firmware.h>
  19 #include <asm/hvcall.h>
  20 #include <asm/io.h>
  21
  22 #include "hv-24x7.h"
  23 #include "hv-24x7-catalog.h"
  24 #include "hv-common.h"
  25
  26 /*
  27  * TODO: Merging events:
  28  * - Think of the hcall as an interface to a 4d array of counters:
  29  *   - x = domains
  30  *   - y = indexes in the domain (core, chip, vcpu, node, etc)
  31  *   - z = offset into the counter space
  32  *   - w = lpars (guest vms, "logical partitions")
  33  * - A single request is: x,y,y_last,z,z_last,w,w_last
  34  *   - this means we can retrieve a rectangle of counters in y,z for a single x.
  35  *
  36  * - Things to consider (ignoring w):
  37  *   - input  cost_per_request = 16
  38  *   - output cost_per_result(ys,zs)  = 8 + 8 * ys + ys * zs
  39  *   - limited number of requests per hcall (must fit into 4K bytes)
  40  *     - 4k = 16 [buffer header] - 16 [request size] * request_count
  41  *     - 255 requests per hcall
  42  *   - sometimes it will be more efficient to read extra data and discard
  43  */
  44
  45 /*
  46  * Example usage:
  47  *  perf stat -e 'hv_24x7/domain=2,offset=8,starting_index=0,lpar=0xffffffff/'
  48  */
  49
  50 /* u3 0-6, one of HV_24X7_PERF_DOMAIN */
  51 EVENT_DEFINE_RANGE_FORMAT(domain, config, 0, 3);
  52 /* u16 */
  53 EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 16, 31);
  54 /* u32, see "data_offset" */
  55 EVENT_DEFINE_RANGE_FORMAT(offset, config, 32, 63);
  56 /* u16 */
  57 EVENT_DEFINE_RANGE_FORMAT(lpar, config1, 0, 15);
  58
  59 EVENT_DEFINE_RANGE(reserved1, config,   4, 15);
  60 EVENT_DEFINE_RANGE(reserved2, config1, 16, 63);
  61 EVENT_DEFINE_RANGE(reserved3, config2,  0, 63);
  62
  63 static struct attribute *format_attrs[] = {
  64         &format_attr_domain.attr,
  65         &format_attr_offset.attr,
  66         &format_attr_starting_index.attr,
  67         &format_attr_lpar.attr,
  68         NULL,
  69 };
  70
  71 static struct attribute_group format_group = {
  72         .name = "format",
  73         .attrs = format_attrs,
  74 };
  75
  76 static struct kmem_cache *hv_page_cache;
  77
  78 static unsigned long h_get_24x7_catalog_page_(unsigned long phys_4096,
  79                                               unsigned long version,
  80                                               unsigned long index)
  81 {
  82         pr_devel("h_get_24x7_catalog_page(0x%lx, %lu, %lu)",
  83                         phys_4096,
  84                         version,
  85                         index);
  86         WARN_ON(!IS_ALIGNED(phys_4096, 4096));
  87         return plpar_hcall_norets(H_GET_24X7_CATALOG_PAGE,
  88                         phys_4096,
  89                         version,
  90                         index);
  91 }
  92
  93 static unsigned long h_get_24x7_catalog_page(char page[],
  94                                              u64 version, u32 index)
  95 {
  96         return h_get_24x7_catalog_page_(virt_to_phys(page),
  97                                         version, index);
  98 }
  99
 100 static ssize_t catalog_read(struct file *filp, struct kobject *kobj,
 101                             struct bin_attribute *bin_attr, char *buf,
 102                             loff_t offset, size_t count)
 103 {
 104         unsigned long hret;
 105         ssize_t ret = 0;
 106         size_t catalog_len = 0, catalog_page_len = 0;
 107         loff_t page_offset = 0;
 108         loff_t offset_in_page;
 109         size_t copy_len;
 110         uint64_t catalog_version_num = 0;
 111         void *page = kmem_cache_alloc(hv_page_cache, GFP_USER);
 112         struct hv_24x7_catalog_page_0 *page_0 = page;
 113         if (!page)
 114                 return -ENOMEM;
 115
 116         hret = h_get_24x7_catalog_page(page, 0, 0);
 117         if (hret) {
 118                 ret = -EIO;
 119                 goto e_free;
 120         }
 121
 122         catalog_version_num = be64_to_cpu(page_0->version);
 123         catalog_page_len = be32_to_cpu(page_0->length);
 124         catalog_len = catalog_page_len * 4096;
 125
 126         page_offset = offset / 4096;
 127         offset_in_page = offset % 4096;
 128
 129         if (page_offset >= catalog_page_len)
 130                 goto e_free;
 131
 132         if (page_offset != 0) {
 133                 hret = h_get_24x7_catalog_page(page, catalog_version_num,
 134                                                page_offset);
 135                 if (hret) {
 136                         ret = -EIO;
 137                         goto e_free;
 138                 }
 139         }
 140
 141         copy_len = 4096 - offset_in_page;
 142         if (copy_len > count)
 143                 copy_len = count;
 144
 145         memcpy(buf, page+offset_in_page, copy_len);
 146         ret = copy_len;
 147
 148 e_free:
 149         if (hret)
 150                 pr_err("h_get_24x7_catalog_page(ver=%lld, page=%lld) failed:"
 151                        " rc=%ld\n",
 152                        catalog_version_num, page_offset, hret);
 153         kmem_cache_free(hv_page_cache, page);
 154
 155         pr_devel("catalog_read: offset=%lld(%lld) count=%zu "
 156                         "catalog_len=%zu(%zu) => %zd\n", offset, page_offset,
 157                         count, catalog_len, catalog_page_len, ret);
 158
 159         return ret;
 160 }
 161
 162 #define PAGE_0_ATTR(_name, _fmt, _expr)                         \
 163 static ssize_t _name##_show(struct device *dev,                 \
 164                             struct device_attribute *dev_attr,  \
 165                             char *buf)                          \
 166 {                                                               \
 167         unsigned long hret;                                     \
 168         ssize_t ret = 0;                                        \
 169         void *page = kmem_cache_alloc(hv_page_cache, GFP_USER); \
 170         struct hv_24x7_catalog_page_0 *page_0 = page;           \
 171         if (!page)                                              \
 172                 return -ENOMEM;                                 \
 173         hret = h_get_24x7_catalog_page(page, 0, 0);             \
 174         if (hret) {                                             \
 175                 ret = -EIO;                                     \
 176                 goto e_free;                                    \
 177         }                                                       \
 178         ret = sprintf(buf, _fmt, _expr);                        \
 179 e_free:                                                         \
 180         kfree(page);                                            \
 181         return ret;                                             \
 182 }                                                               \
 183 static DEVICE_ATTR_RO(_name)
 184
 185 PAGE_0_ATTR(catalog_version, "%lld\n",
 186                 (unsigned long long)be64_to_cpu(page_0->version));
 187 PAGE_0_ATTR(catalog_len, "%lld\n",
 188                 (unsigned long long)be32_to_cpu(page_0->length) * 4096);
 189 static BIN_ATTR_RO(catalog, 0/* real length varies */);
 190
 191 static struct bin_attribute *if_bin_attrs[] = {
 192         &bin_attr_catalog,
 193         NULL,
 194 };
 195
 196 static struct attribute *if_attrs[] = {
 197         &dev_attr_catalog_len.attr,
 198         &dev_attr_catalog_version.attr,
 199         NULL,
 200 };
 201
 202 static struct attribute_group if_group = {
 203         .name = "interface",
 204         .bin_attrs = if_bin_attrs,
 205         .attrs = if_attrs,
 206 };
 207
 208 static const struct attribute_group *attr_groups[] = {
 209         &format_group,
 210         &if_group,
 211         NULL,
 212 };
 213
 214 static bool is_physical_domain(int domain)
 215 {
 216         return  domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CHIP ||
 217                 domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CORE;
 218 }
 219
 220 static unsigned long single_24x7_request(u8 domain, u32 offset, u16 ix,
 221                                          u16 lpar, u64 *res,
 222                                          bool success_expected)
 223 {
 224         unsigned long ret = -ENOMEM;
 225
 226         /*
 227          * request_buffer and result_buffer are not required to be 4k aligned,
 228          * but are not allowed to cross any 4k boundary. Aligning them to 4k is
 229          * the simplest way to ensure that.
 230          */
 231         struct reqb {
 232                 struct hv_24x7_request_buffer buf;
 233                 struct hv_24x7_request req;
 234         } __packed *request_buffer;
 235
 236         struct {
 237                 struct hv_24x7_data_result_buffer buf;
 238                 struct hv_24x7_result res;
 239                 struct hv_24x7_result_element elem;
 240                 __be64 result;
 241         } __packed *result_buffer;
 242
 243         BUILD_BUG_ON(sizeof(*request_buffer) > 4096);
 244         BUILD_BUG_ON(sizeof(*result_buffer) > 4096);
 245
 246         request_buffer = kmem_cache_zalloc(hv_page_cache, GFP_USER);
 247         if (!request_buffer)
 248                 goto out;
 249
 250         result_buffer = kmem_cache_zalloc(hv_page_cache, GFP_USER);
 251         if (!result_buffer)
 252                 goto out_free_request_buffer;
 253
 254         *request_buffer = (struct reqb) {
 255                 .buf = {
 256                         .interface_version = HV_24X7_IF_VERSION_CURRENT,
 257                         .num_requests = 1,
 258                 },
 259                 .req = {
 260                         .performance_domain = domain,
 261                         .data_size = cpu_to_be16(8),
 262                         .data_offset = cpu_to_be32(offset),
 263                         .starting_lpar_ix = cpu_to_be16(lpar),
 264                         .max_num_lpars = cpu_to_be16(1),
 265                         .starting_ix = cpu_to_be16(ix),
 266                         .max_ix = cpu_to_be16(1),
 267                 }
 268         };
 269
 270         ret = plpar_hcall_norets(H_GET_24X7_DATA,
 271                         virt_to_phys(request_buffer), sizeof(*request_buffer),
 272                         virt_to_phys(result_buffer),  sizeof(*result_buffer));
 273
 274         if (ret) {
 275                 if (success_expected)
 276                         pr_err_ratelimited("hcall failed: %d %#x %#x %d => "
 277                                 "0x%lx (%ld) detail=0x%x failing ix=%x\n",
 278                                 domain, offset, ix, lpar, ret, ret,
 279                                 result_buffer->buf.detailed_rc,
 280                                 result_buffer->buf.failing_request_ix);
 281                 goto out_free_result_buffer;
 282         }
 283
 284         *res = be64_to_cpu(result_buffer->result);
 285
 286 out_free_result_buffer:
 287         kfree(result_buffer);
 288 out_free_request_buffer:
 289         kfree(request_buffer);
 290 out:
 291         return ret;
 292 }
 293
 294 static unsigned long event_24x7_request(struct perf_event *event, u64 *res,
 295                 bool success_expected)
 296 {
 297         return single_24x7_request(event_get_domain(event),
 298                                 event_get_offset(event),
 299                                 event_get_starting_index(event),
 300                                 event_get_lpar(event),
 301                                 res,
 302                                 success_expected);
 303 }
 304
 305 static int h_24x7_event_init(struct perf_event *event)
 306 {
 307         struct hv_perf_caps caps;
 308         unsigned domain;
 309         unsigned long hret;
 310         u64 ct;
 311
 312         /* Not our event */
 313         if (event->attr.type != event->pmu->type)
 314                 return -ENOENT;
 315
 316         /* Unused areas must be 0 */
 317         if (event_get_reserved1(event) ||
 318             event_get_reserved2(event) ||
 319             event_get_reserved3(event)) {
 320                 pr_devel("reserved set when forbidden 0x%llx(0x%llx) 0x%llx(0x%llx) 0x%llx(0x%llx)\n",
 321                                 event->attr.config,
 322                                 event_get_reserved1(event),
 323                                 event->attr.config1,
 324                                 event_get_reserved2(event),
 325                                 event->attr.config2,
 326                                 event_get_reserved3(event));
 327                 return -EINVAL;
 328         }
 329
 330         /* unsupported modes and filters */
 331         if (event->attr.exclude_user   ||
 332             event->attr.exclude_kernel ||
 333             event->attr.exclude_hv     ||
 334             event->attr.exclude_idle   ||
 335             event->attr.exclude_host   ||
 336             event->attr.exclude_guest)
 337                 return -EINVAL;
 338
 339         /* no branch sampling */
 340         if (has_branch_stack(event))
 341                 return -EOPNOTSUPP;
 342
 343         /* offset must be 8 byte aligned */
 344         if (event_get_offset(event) % 8) {
 345                 pr_devel("bad alignment\n");
 346                 return -EINVAL;
 347         }
 348
 349         /* Domains above 6 are invalid */
 350         domain = event_get_domain(event);
 351         if (domain > 6) {
 352                 pr_devel("invalid domain %d\n", domain);
 353                 return -EINVAL;
 354         }
 355
 356         hret = hv_perf_caps_get(&caps);
 357         if (hret) {
 358                 pr_devel("could not get capabilities: rc=%ld\n", hret);
 359                 return -EIO;
 360         }
 361
 362         /* PHYSICAL domains & other lpars require extra capabilities */
 363         if (!caps.collect_privileged && (is_physical_domain(domain) ||
 364                 (event_get_lpar(event) != event_get_lpar_max()))) {
 365                 pr_devel("hv permissions disallow: is_physical_domain:%d, lpar=0x%llx\n",
 366                                 is_physical_domain(domain),
 367                                 event_get_lpar(event));
 368                 return -EACCES;
 369         }
 370
 371         /* see if the event complains */
 372         if (event_24x7_request(event, &ct, false)) {
 373                 pr_devel("test hcall failed\n");
 374                 return -EIO;
 375         }
 376
 377         return 0;
 378 }
 379
 380 static u64 h_24x7_get_value(struct perf_event *event)
 381 {
 382         unsigned long ret;
 383         u64 ct;
 384         ret = event_24x7_request(event, &ct, true);
 385         if (ret)
 386                 /* We checked this in event init, shouldn't fail here... */
 387                 return 0;
 388
 389         return ct;
 390 }
 391
 392 static void h_24x7_event_update(struct perf_event *event)
 393 {
 394         s64 prev;
 395         u64 now;
 396         now = h_24x7_get_value(event);
 397         prev = local64_xchg(&event->hw.prev_count, now);
 398         local64_add(now - prev, &event->count);
 399 }
 400
 401 static void h_24x7_event_start(struct perf_event *event, int flags)
 402 {
 403         if (flags & PERF_EF_RELOAD)
 404                 local64_set(&event->hw.prev_count, h_24x7_get_value(event));
 405 }
 406
 407 static void h_24x7_event_stop(struct perf_event *event, int flags)
 408 {
 409         h_24x7_event_update(event);
 410 }
 411
 412 static int h_24x7_event_add(struct perf_event *event, int flags)
 413 {
 414         if (flags & PERF_EF_START)
 415                 h_24x7_event_start(event, flags);
 416
 417         return 0;
 418 }
 419
 420 static struct pmu h_24x7_pmu = {
 421         .task_ctx_nr = perf_invalid_context,
 422
 423         .name = "hv_24x7",
 424         .attr_groups = attr_groups,
 425         .event_init  = h_24x7_event_init,
 426         .add         = h_24x7_event_add,
 427         .del         = h_24x7_event_stop,
 428         .start       = h_24x7_event_start,
 429         .stop        = h_24x7_event_stop,
 430         .read        = h_24x7_event_update,
 431 };
 432
 433 static int hv_24x7_init(void)
 434 {
 435         int r;
 436         unsigned long hret;
 437         struct hv_perf_caps caps;
 438
 439         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 440                 pr_debug("not a virtualized system, not enabling\n");
 441                 return -ENODEV;
 442         }
 443
 444         hret = hv_perf_caps_get(&caps);
 445         if (hret) {
 446                 pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
 447                                 hret);
 448                 return -ENODEV;
 449         }
 450
 451         hv_page_cache = kmem_cache_create("hv-page-4096", 4096, 4096, 0, NULL);
 452         if (!hv_page_cache)
 453                 return -ENOMEM;
 454
 455         /* sampling not supported */
 456         h_24x7_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 457
 458         r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1);
 459         if (r)
 460                 return r;
 461
 462         return 0;
 463 }
 464
 465 device_initcall(hv_24x7_init);