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(char page[static 4096],
 159                                              u32 version, u32 index)
 160 {
 161         WARN_ON(!IS_ALIGNED((unsigned long)page, 4096));
 162         return plpar_hcall_norets(H_GET_24X7_CATALOG_PAGE,
 163                         virt_to_phys(page),
 164                         version,
 165                         index);
 166 }
 167
 168 static ssize_t catalog_read(struct file *filp, struct kobject *kobj,
 169                             struct bin_attribute *bin_attr, char *buf,
 170                             loff_t offset, size_t count)
 171 {
 172         unsigned long hret;
 173         ssize_t ret = 0;
 174         size_t catalog_len = 0, catalog_page_len = 0, page_count = 0;
 175         loff_t page_offset = 0;
 176         uint32_t catalog_version_num = 0;
 177         void *page = kmem_cache_alloc(hv_page_cache, GFP_USER);
 178         struct hv_24x7_catalog_page_0 *page_0 = page;
 179         if (!page)
 180                 return -ENOMEM;
 181
 182         hret = h_get_24x7_catalog_page(page, 0, 0);
 183         if (hret) {
 184                 ret = -EIO;
 185                 goto e_free;
 186         }
 187
 188         catalog_version_num = be32_to_cpu(page_0->version);
 189         catalog_page_len = be32_to_cpu(page_0->length);
 190         catalog_len = catalog_page_len * 4096;
 191
 192         page_offset = offset / 4096;
 193         page_count  = count  / 4096;
 194
 195         if (page_offset >= catalog_page_len)
 196                 goto e_free;
 197
 198         if (page_offset != 0) {
 199                 hret = h_get_24x7_catalog_page(page, catalog_version_num,
 200                                                page_offset);
 201                 if (hret) {
 202                         ret = -EIO;
 203                         goto e_free;
 204                 }
 205         }
 206
 207         ret = read_offset_data(buf, count, offset,
 208                                 page, 4096, page_offset * 4096);
 209 e_free:
 210         if (hret)
 211                 pr_err("h_get_24x7_catalog_page(ver=%d, page=%lld) failed: rc=%ld\n",
 212                                 catalog_version_num, page_offset, hret);
 213         kfree(page);
 214
 215         pr_devel("catalog_read: offset=%lld(%lld) count=%zu(%zu) catalog_len=%zu(%zu) => %zd\n",
 216                         offset, page_offset, count, page_count, catalog_len,
 217                         catalog_page_len, ret);
 218
 219         return ret;
 220 }
 221
 222 #define PAGE_0_ATTR(_name, _fmt, _expr)                         \
 223 static ssize_t _name##_show(struct device *dev,                 \
 224                             struct device_attribute *dev_attr,  \
 225                             char *buf)                          \
 226 {                                                               \
 227         unsigned long hret;                                     \
 228         ssize_t ret = 0;                                        \
 229         void *page = kmem_cache_alloc(hv_page_cache, GFP_USER); \
 230         struct hv_24x7_catalog_page_0 *page_0 = page;           \
 231         if (!page)                                              \
 232                 return -ENOMEM;                                 \
 233         hret = h_get_24x7_catalog_page(page, 0, 0);             \
 234         if (hret) {                                             \
 235                 ret = -EIO;                                     \
 236                 goto e_free;                                    \
 237         }                                                       \
 238         ret = sprintf(buf, _fmt, _expr);                        \
 239 e_free:                                                         \
 240         kfree(page);                                            \
 241         return ret;                                             \
 242 }                                                               \
 243 static DEVICE_ATTR_RO(_name)
 244
 245 PAGE_0_ATTR(catalog_version, "%lld\n",
 246                 (unsigned long long)be32_to_cpu(page_0->version));
 247 PAGE_0_ATTR(catalog_len, "%lld\n",
 248                 (unsigned long long)be32_to_cpu(page_0->length) * 4096);
 249 static BIN_ATTR_RO(catalog, 0/* real length varies */);
 250
 251 static struct bin_attribute *if_bin_attrs[] = {
 252         &bin_attr_catalog,
 253         NULL,
 254 };
 255
 256 static struct attribute *if_attrs[] = {
 257         &dev_attr_catalog_len.attr,
 258         &dev_attr_catalog_version.attr,
 259         NULL,
 260 };
 261
 262 static struct attribute_group if_group = {
 263         .name = "interface",
 264         .bin_attrs = if_bin_attrs,
 265         .attrs = if_attrs,
 266 };
 267
 268 static const struct attribute_group *attr_groups[] = {
 269         &format_group,
 270         &if_group,
 271         NULL,
 272 };
 273
 274 static bool is_physical_domain(int domain)
 275 {
 276         return  domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CHIP ||
 277                 domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CORE;
 278 }
 279
 280 static unsigned long single_24x7_request(u8 domain, u32 offset, u16 ix,
 281                                          u16 lpar, u64 *res,
 282                                          bool success_expected)
 283 {
 284         unsigned long ret;
 285
 286         /*
 287          * request_buffer and result_buffer are not required to be 4k aligned,
 288          * but are not allowed to cross any 4k boundary. Aligning them to 4k is
 289          * the simplest way to ensure that.
 290          */
 291         struct reqb {
 292                 struct hv_24x7_request_buffer buf;
 293                 struct hv_24x7_request req;
 294         } __packed __aligned(4096) request_buffer = {
 295                 .buf = {
 296                         .interface_version = HV_24X7_IF_VERSION_CURRENT,
 297                         .num_requests = 1,
 298                 },
 299                 .req = {
 300                         .performance_domain = domain,
 301                         .data_size = cpu_to_be16(8),
 302                         .data_offset = cpu_to_be32(offset),
 303                         .starting_lpar_ix = cpu_to_be16(lpar),
 304                         .max_num_lpars = cpu_to_be16(1),
 305                         .starting_ix = cpu_to_be16(ix),
 306                         .max_ix = cpu_to_be16(1),
 307                 }
 308         };
 309
 310         struct resb {
 311                 struct hv_24x7_data_result_buffer buf;
 312                 struct hv_24x7_result res;
 313                 struct hv_24x7_result_element elem;
 314                 __be64 result;
 315         } __packed __aligned(4096) result_buffer = {};
 316
 317         ret = plpar_hcall_norets(H_GET_24X7_DATA,
 318                         virt_to_phys(&request_buffer), sizeof(request_buffer),
 319                         virt_to_phys(&result_buffer),  sizeof(result_buffer));
 320
 321         if (ret) {
 322                 if (success_expected)
 323                         pr_err_ratelimited("hcall failed: %d %#x %#x %d => 0x%lx (%ld) detail=0x%x failing ix=%x\n",
 324                                         domain, offset, ix, lpar,
 325                                         ret, ret,
 326                                         result_buffer.buf.detailed_rc,
 327                                         result_buffer.buf.failing_request_ix);
 328                 return ret;
 329         }
 330
 331         *res = be64_to_cpu(result_buffer.result);
 332         return ret;
 333 }
 334
 335 static unsigned long event_24x7_request(struct perf_event *event, u64 *res,
 336                 bool success_expected)
 337 {
 338         return single_24x7_request(event_get_domain(event),
 339                                 event_get_offset(event),
 340                                 event_get_starting_index(event),
 341                                 event_get_lpar(event),
 342                                 res,
 343                                 success_expected);
 344 }
 345
 346 static int h_24x7_event_init(struct perf_event *event)
 347 {
 348         struct hv_perf_caps caps;
 349         unsigned domain;
 350         unsigned long hret;
 351         u64 ct;
 352
 353         /* Not our event */
 354         if (event->attr.type != event->pmu->type)
 355                 return -ENOENT;
 356
 357         /* Unused areas must be 0 */
 358         if (event_get_reserved1(event) ||
 359             event_get_reserved2(event) ||
 360             event_get_reserved3(event)) {
 361                 pr_devel("reserved set when forbidden 0x%llx(0x%llx) 0x%llx(0x%llx) 0x%llx(0x%llx)\n",
 362                                 event->attr.config,
 363                                 event_get_reserved1(event),
 364                                 event->attr.config1,
 365                                 event_get_reserved2(event),
 366                                 event->attr.config2,
 367                                 event_get_reserved3(event));
 368                 return -EINVAL;
 369         }
 370
 371         /* unsupported modes and filters */
 372         if (event->attr.exclude_user   ||
 373             event->attr.exclude_kernel ||
 374             event->attr.exclude_hv     ||
 375             event->attr.exclude_idle   ||
 376             event->attr.exclude_host   ||
 377             event->attr.exclude_guest  ||
 378             is_sampling_event(event)) /* no sampling */
 379                 return -EINVAL;
 380
 381         /* no branch sampling */
 382         if (has_branch_stack(event))
 383                 return -EOPNOTSUPP;
 384
 385         /* offset must be 8 byte aligned */
 386         if (event_get_offset(event) % 8) {
 387                 pr_devel("bad alignment\n");
 388                 return -EINVAL;
 389         }
 390
 391         /* Domains above 6 are invalid */
 392         domain = event_get_domain(event);
 393         if (domain > 6) {
 394                 pr_devel("invalid domain %d\n", domain);
 395                 return -EINVAL;
 396         }
 397
 398         hret = hv_perf_caps_get(&caps);
 399         if (hret) {
 400                 pr_devel("could not get capabilities: rc=%ld\n", hret);
 401                 return -EIO;
 402         }
 403
 404         /* PHYSICAL domains & other lpars require extra capabilities */
 405         if (!caps.collect_privileged && (is_physical_domain(domain) ||
 406                 (event_get_lpar(event) != event_get_lpar_max()))) {
 407                 pr_devel("hv permisions disallow: is_physical_domain:%d, lpar=0x%llx\n",
 408                                 is_physical_domain(domain),
 409                                 event_get_lpar(event));
 410                 return -EACCES;
 411         }
 412
 413         /* see if the event complains */
 414         if (event_24x7_request(event, &ct, false)) {
 415                 pr_devel("test hcall failed\n");
 416                 return -EIO;
 417         }
 418
 419         return 0;
 420 }
 421
 422 static u64 h_24x7_get_value(struct perf_event *event)
 423 {
 424         unsigned long ret;
 425         u64 ct;
 426         ret = event_24x7_request(event, &ct, true);
 427         if (ret)
 428                 /* We checked this in event init, shouldn't fail here... */
 429                 return 0;
 430
 431         return ct;
 432 }
 433
 434 static void h_24x7_event_update(struct perf_event *event)
 435 {
 436         s64 prev;
 437         u64 now;
 438         now = h_24x7_get_value(event);
 439         prev = local64_xchg(&event->hw.prev_count, now);
 440         local64_add(now - prev, &event->count);
 441 }
 442
 443 static void h_24x7_event_start(struct perf_event *event, int flags)
 444 {
 445         if (flags & PERF_EF_RELOAD)
 446                 local64_set(&event->hw.prev_count, h_24x7_get_value(event));
 447 }
 448
 449 static void h_24x7_event_stop(struct perf_event *event, int flags)
 450 {
 451         h_24x7_event_update(event);
 452 }
 453
 454 static int h_24x7_event_add(struct perf_event *event, int flags)
 455 {
 456         if (flags & PERF_EF_START)
 457                 h_24x7_event_start(event, flags);
 458
 459         return 0;
 460 }
 461
 462 static int h_24x7_event_idx(struct perf_event *event)
 463 {
 464         return 0;
 465 }
 466
 467 static struct pmu h_24x7_pmu = {
 468         .task_ctx_nr = perf_invalid_context,
 469
 470         .name = "hv_24x7",
 471         .attr_groups = attr_groups,
 472         .event_init  = h_24x7_event_init,
 473         .add         = h_24x7_event_add,
 474         .del         = h_24x7_event_stop,
 475         .start       = h_24x7_event_start,
 476         .stop        = h_24x7_event_stop,
 477         .read        = h_24x7_event_update,
 478         .event_idx   = h_24x7_event_idx,
 479 };
 480
 481 static int hv_24x7_init(void)
 482 {
 483         int r;
 484         unsigned long hret;
 485         struct hv_perf_caps caps;
 486
 487         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 488                 pr_info("not a virtualized system, not enabling\n");
 489                 return -ENODEV;
 490         }
 491
 492         hret = hv_perf_caps_get(&caps);
 493         if (hret) {
 494                 pr_info("could not obtain capabilities, error 0x%80lx, not enabling\n",
 495                                 hret);
 496                 return -ENODEV;
 497         }
 498
 499         hv_page_cache = kmem_cache_create("hv-page-4096", 4096, 4096, 0, NULL);
 500         if (!hv_page_cache)
 501                 return -ENOMEM;
 502
 503         r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1);
 504         if (r)
 505                 return r;
 506
 507         return 0;
 508 }
 509
 510 device_initcall(hv_24x7_init);