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 /*
  79  * read_offset_data - copy data from one buffer to another while treating the
  80  *                    source buffer as a small view on the total avaliable
  81  *                    source data.
  82  *
  83  * @dest: buffer to copy into
  84  * @dest_len: length of @dest in bytes
  85  * @requested_offset: the offset within the source data we want. Must be > 0
  86  * @src: buffer to copy data from
  87  * @src_len: length of @src in bytes
  88  * @source_offset: the offset in the sorce data that (src,src_len) refers to.
  89  *                 Must be > 0
  90  *
  91  * returns the number of bytes copied.
  92  *
  93  * The following ascii art shows the various buffer possitioning we need to
  94  * handle, assigns some arbitrary varibles to points on the buffer, and then
  95  * shows how we fiddle with those values to get things we care about (copy
  96  * start in src and copy len)
  97  *
  98  * s = @src buffer
  99  * d = @dest buffer
 100  * '.' areas in d are written to.
 101  *
 102  *                       u
 103  *   x         w         v  z
 104  * d           |.........|
 105  * s |----------------------|
 106  *
 107  *                      u
 108  *   x         w        z     v
 109  * d           |........------|
 110  * s |------------------|
 111  *
 112  *   x         w        u,z,v
 113  * d           |........|
 114  * s |------------------|
 115  *
 116  *   x,w                u,v,z
 117  * d |..................|
 118  * s |------------------|
 119  *
 120  *   x        u
 121  *   w        v         z
 122  * d |........|
 123  * s |------------------|
 124  *
 125  *   x      z   w      v
 126  * d            |------|
 127  * s |------|
 128  *
 129  * x = source_offset
 130  * w = requested_offset
 131  * z = source_offset + src_len
 132  * v = requested_offset + dest_len
 133  *
 134  * w_offset_in_s = w - x = requested_offset - source_offset
 135  * z_offset_in_s = z - x = src_len
 136  * v_offset_in_s = v - x = request_offset + dest_len - src_len
 137  */
 138 static ssize_t read_offset_data(void *dest, size_t dest_len,
 139                                 loff_t requested_offset, void *src,
 140                                 size_t src_len, loff_t source_offset)
 141 {
 142         size_t w_offset_in_s = requested_offset - source_offset;
 143         size_t z_offset_in_s = src_len;
 144         size_t v_offset_in_s = requested_offset + dest_len - src_len;
 145         size_t u_offset_in_s = min(z_offset_in_s, v_offset_in_s);
 146         size_t copy_len = u_offset_in_s - w_offset_in_s;
 147
 148         if (requested_offset < 0 || source_offset < 0)
 149                 return -EINVAL;
 150
 151         if (z_offset_in_s <= w_offset_in_s)
 152                 return 0;
 153
 154         memcpy(dest, src + w_offset_in_s, copy_len);
 155         return copy_len;
 156 }
 157
 158 static unsigned long h_get_24x7_catalog_page_(unsigned long phys_4096,
 159                                               unsigned long version,
 160                                               unsigned long index)
 161 {
 162         pr_devel("h_get_24x7_catalog_page(0x%lx, %lu, %lu)",
 163                         phys_4096,
 164                         version,
 165                         index);
 166         WARN_ON(!IS_ALIGNED(phys_4096, 4096));
 167         return plpar_hcall_norets(H_GET_24X7_CATALOG_PAGE,
 168                         phys_4096,
 169                         version,
 170                         index);
 171 }
 172
 173 static unsigned long h_get_24x7_catalog_page(char page[],
 174                                              u64 version, u32 index)
 175 {
 176         return h_get_24x7_catalog_page_(virt_to_phys(page),
 177                                         version, index);
 178 }
 179
 180 static ssize_t catalog_read(struct file *filp, struct kobject *kobj,
 181                             struct bin_attribute *bin_attr, char *buf,
 182                             loff_t offset, size_t count)
 183 {
 184         unsigned long hret;
 185         ssize_t ret = 0;
 186         size_t catalog_len = 0, catalog_page_len = 0, page_count = 0;
 187         loff_t page_offset = 0;
 188         uint64_t catalog_version_num = 0;
 189         void *page = kmem_cache_alloc(hv_page_cache, GFP_USER);
 190         struct hv_24x7_catalog_page_0 *page_0 = page;
 191         if (!page)
 192                 return -ENOMEM;
 193
 194         hret = h_get_24x7_catalog_page(page, 0, 0);
 195         if (hret) {
 196                 ret = -EIO;
 197                 goto e_free;
 198         }
 199
 200         catalog_version_num = be64_to_cpu(page_0->version);
 201         catalog_page_len = be32_to_cpu(page_0->length);
 202         catalog_len = catalog_page_len * 4096;
 203
 204         page_offset = offset / 4096;
 205         page_count  = count  / 4096;
 206
 207         if (page_offset >= catalog_page_len)
 208                 goto e_free;
 209
 210         if (page_offset != 0) {
 211                 hret = h_get_24x7_catalog_page(page, catalog_version_num,
 212                                                page_offset);
 213                 if (hret) {
 214                         ret = -EIO;
 215                         goto e_free;
 216                 }
 217         }
 218
 219         ret = read_offset_data(buf, count, offset,
 220                                 page, 4096, page_offset * 4096);
 221 e_free:
 222         if (hret)
 223                 pr_err("h_get_24x7_catalog_page(ver=%lld, page=%lld) failed:"
 224                        " rc=%ld\n",
 225                        catalog_version_num, page_offset, hret);
 226         kfree(page);
 227
 228         pr_devel("catalog_read: offset=%lld(%lld) count=%zu(%zu) catalog_len=%zu(%zu) => %zd\n",
 229                         offset, page_offset, count, page_count, catalog_len,
 230                         catalog_page_len, ret);
 231
 232         return ret;
 233 }
 234
 235 #define PAGE_0_ATTR(_name, _fmt, _expr)                         \
 236 static ssize_t _name##_show(struct device *dev,                 \
 237                             struct device_attribute *dev_attr,  \
 238                             char *buf)                          \
 239 {                                                               \
 240         unsigned long hret;                                     \
 241         ssize_t ret = 0;                                        \
 242         void *page = kmem_cache_alloc(hv_page_cache, GFP_USER); \
 243         struct hv_24x7_catalog_page_0 *page_0 = page;           \
 244         if (!page)                                              \
 245                 return -ENOMEM;                                 \
 246         hret = h_get_24x7_catalog_page(page, 0, 0);             \
 247         if (hret) {                                             \
 248                 ret = -EIO;                                     \
 249                 goto e_free;                                    \
 250         }                                                       \
 251         ret = sprintf(buf, _fmt, _expr);                        \
 252 e_free:                                                         \
 253         kfree(page);                                            \
 254         return ret;                                             \
 255 }                                                               \
 256 static DEVICE_ATTR_RO(_name)
 257
 258 PAGE_0_ATTR(catalog_version, "%lld\n",
 259                 (unsigned long long)be64_to_cpu(page_0->version));
 260 PAGE_0_ATTR(catalog_len, "%lld\n",
 261                 (unsigned long long)be32_to_cpu(page_0->length) * 4096);
 262 static BIN_ATTR_RO(catalog, 0/* real length varies */);
 263
 264 static struct bin_attribute *if_bin_attrs[] = {
 265         &bin_attr_catalog,
 266         NULL,
 267 };
 268
 269 static struct attribute *if_attrs[] = {
 270         &dev_attr_catalog_len.attr,
 271         &dev_attr_catalog_version.attr,
 272         NULL,
 273 };
 274
 275 static struct attribute_group if_group = {
 276         .name = "interface",
 277         .bin_attrs = if_bin_attrs,
 278         .attrs = if_attrs,
 279 };
 280
 281 static const struct attribute_group *attr_groups[] = {
 282         &format_group,
 283         &if_group,
 284         NULL,
 285 };
 286
 287 static bool is_physical_domain(int domain)
 288 {
 289         return  domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CHIP ||
 290                 domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CORE;
 291 }
 292
 293 static unsigned long single_24x7_request(u8 domain, u32 offset, u16 ix,
 294                                          u16 lpar, u64 *res,
 295                                          bool success_expected)
 296 {
 297         unsigned long ret;
 298
 299         /*
 300          * request_buffer and result_buffer are not required to be 4k aligned,
 301          * but are not allowed to cross any 4k boundary. Aligning them to 4k is
 302          * the simplest way to ensure that.
 303          */
 304         struct reqb {
 305                 struct hv_24x7_request_buffer buf;
 306                 struct hv_24x7_request req;
 307         } __packed __aligned(4096) request_buffer = {
 308                 .buf = {
 309                         .interface_version = HV_24X7_IF_VERSION_CURRENT,
 310                         .num_requests = 1,
 311                 },
 312                 .req = {
 313                         .performance_domain = domain,
 314                         .data_size = cpu_to_be16(8),
 315                         .data_offset = cpu_to_be32(offset),
 316                         .starting_lpar_ix = cpu_to_be16(lpar),
 317                         .max_num_lpars = cpu_to_be16(1),
 318                         .starting_ix = cpu_to_be16(ix),
 319                         .max_ix = cpu_to_be16(1),
 320                 }
 321         };
 322
 323         struct resb {
 324                 struct hv_24x7_data_result_buffer buf;
 325                 struct hv_24x7_result res;
 326                 struct hv_24x7_result_element elem;
 327                 __be64 result;
 328         } __packed __aligned(4096) result_buffer = {};
 329
 330         ret = plpar_hcall_norets(H_GET_24X7_DATA,
 331                         virt_to_phys(&request_buffer), sizeof(request_buffer),
 332                         virt_to_phys(&result_buffer),  sizeof(result_buffer));
 333
 334         if (ret) {
 335                 if (success_expected)
 336                         pr_err_ratelimited("hcall failed: %d %#x %#x %d => 0x%lx (%ld) detail=0x%x failing ix=%x\n",
 337                                         domain, offset, ix, lpar,
 338                                         ret, ret,
 339                                         result_buffer.buf.detailed_rc,
 340                                         result_buffer.buf.failing_request_ix);
 341                 return ret;
 342         }
 343
 344         *res = be64_to_cpu(result_buffer.result);
 345         return ret;
 346 }
 347
 348 static unsigned long event_24x7_request(struct perf_event *event, u64 *res,
 349                 bool success_expected)
 350 {
 351         return single_24x7_request(event_get_domain(event),
 352                                 event_get_offset(event),
 353                                 event_get_starting_index(event),
 354                                 event_get_lpar(event),
 355                                 res,
 356                                 success_expected);
 357 }
 358
 359 static int h_24x7_event_init(struct perf_event *event)
 360 {
 361         struct hv_perf_caps caps;
 362         unsigned domain;
 363         unsigned long hret;
 364         u64 ct;
 365
 366         /* Not our event */
 367         if (event->attr.type != event->pmu->type)
 368                 return -ENOENT;
 369
 370         /* Unused areas must be 0 */
 371         if (event_get_reserved1(event) ||
 372             event_get_reserved2(event) ||
 373             event_get_reserved3(event)) {
 374                 pr_devel("reserved set when forbidden 0x%llx(0x%llx) 0x%llx(0x%llx) 0x%llx(0x%llx)\n",
 375                                 event->attr.config,
 376                                 event_get_reserved1(event),
 377                                 event->attr.config1,
 378                                 event_get_reserved2(event),
 379                                 event->attr.config2,
 380                                 event_get_reserved3(event));
 381                 return -EINVAL;
 382         }
 383
 384         /* unsupported modes and filters */
 385         if (event->attr.exclude_user   ||
 386             event->attr.exclude_kernel ||
 387             event->attr.exclude_hv     ||
 388             event->attr.exclude_idle   ||
 389             event->attr.exclude_host   ||
 390             event->attr.exclude_guest  ||
 391             is_sampling_event(event)) /* no sampling */
 392                 return -EINVAL;
 393
 394         /* no branch sampling */
 395         if (has_branch_stack(event))
 396                 return -EOPNOTSUPP;
 397
 398         /* offset must be 8 byte aligned */
 399         if (event_get_offset(event) % 8) {
 400                 pr_devel("bad alignment\n");
 401                 return -EINVAL;
 402         }
 403
 404         /* Domains above 6 are invalid */
 405         domain = event_get_domain(event);
 406         if (domain > 6) {
 407                 pr_devel("invalid domain %d\n", domain);
 408                 return -EINVAL;
 409         }
 410
 411         hret = hv_perf_caps_get(&caps);
 412         if (hret) {
 413                 pr_devel("could not get capabilities: rc=%ld\n", hret);
 414                 return -EIO;
 415         }
 416
 417         /* PHYSICAL domains & other lpars require extra capabilities */
 418         if (!caps.collect_privileged && (is_physical_domain(domain) ||
 419                 (event_get_lpar(event) != event_get_lpar_max()))) {
 420                 pr_devel("hv permisions disallow: is_physical_domain:%d, lpar=0x%llx\n",
 421                                 is_physical_domain(domain),
 422                                 event_get_lpar(event));
 423                 return -EACCES;
 424         }
 425
 426         /* see if the event complains */
 427         if (event_24x7_request(event, &ct, false)) {
 428                 pr_devel("test hcall failed\n");
 429                 return -EIO;
 430         }
 431
 432         return 0;
 433 }
 434
 435 static u64 h_24x7_get_value(struct perf_event *event)
 436 {
 437         unsigned long ret;
 438         u64 ct;
 439         ret = event_24x7_request(event, &ct, true);
 440         if (ret)
 441                 /* We checked this in event init, shouldn't fail here... */
 442                 return 0;
 443
 444         return ct;
 445 }
 446
 447 static void h_24x7_event_update(struct perf_event *event)
 448 {
 449         s64 prev;
 450         u64 now;
 451         now = h_24x7_get_value(event);
 452         prev = local64_xchg(&event->hw.prev_count, now);
 453         local64_add(now - prev, &event->count);
 454 }
 455
 456 static void h_24x7_event_start(struct perf_event *event, int flags)
 457 {
 458         if (flags & PERF_EF_RELOAD)
 459                 local64_set(&event->hw.prev_count, h_24x7_get_value(event));
 460 }
 461
 462 static void h_24x7_event_stop(struct perf_event *event, int flags)
 463 {
 464         h_24x7_event_update(event);
 465 }
 466
 467 static int h_24x7_event_add(struct perf_event *event, int flags)
 468 {
 469         if (flags & PERF_EF_START)
 470                 h_24x7_event_start(event, flags);
 471
 472         return 0;
 473 }
 474
 475 static int h_24x7_event_idx(struct perf_event *event)
 476 {
 477         return 0;
 478 }
 479
 480 static struct pmu h_24x7_pmu = {
 481         .task_ctx_nr = perf_invalid_context,
 482
 483         .name = "hv_24x7",
 484         .attr_groups = attr_groups,
 485         .event_init  = h_24x7_event_init,
 486         .add         = h_24x7_event_add,
 487         .del         = h_24x7_event_stop,
 488         .start       = h_24x7_event_start,
 489         .stop        = h_24x7_event_stop,
 490         .read        = h_24x7_event_update,
 491         .event_idx   = h_24x7_event_idx,
 492 };
 493
 494 static int hv_24x7_init(void)
 495 {
 496         int r;
 497         unsigned long hret;
 498         struct hv_perf_caps caps;
 499
 500         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 501                 pr_debug("not a virtualized system, not enabling\n");
 502                 return -ENODEV;
 503         }
 504
 505         hret = hv_perf_caps_get(&caps);
 506         if (hret) {
 507                 pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
 508                                 hret);
 509                 return -ENODEV;
 510         }
 511
 512         hv_page_cache = kmem_cache_create("hv-page-4096", 4096, 4096, 0, NULL);
 513         if (!hv_page_cache)
 514                 return -ENOMEM;
 515
 516         r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1);
 517         if (r)
 518                 return r;
 519
 520         return 0;
 521 }
 522
 523 device_initcall(hv_24x7_init);