arch/powerpc/perf/hv-gpci.c

   1 /*
   2  * Hypervisor supplied "gpci" ("get performance counter info") performance
   3  * counter support
   4  *
   5  * Author: Cody P Schafer <cody@linux.vnet.ibm.com>
   6  * Copyright 2014 IBM Corporation.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version
  11  * 2 of the License, or (at your option) any later version.
  12  */
  13
  14 #define pr_fmt(fmt) "hv-gpci: " fmt
  15
  16 #include <linux/init.h>
  17 #include <linux/perf_event.h>
  18 #include <asm/firmware.h>
  19 #include <asm/hvcall.h>
  20 #include <asm/io.h>
  21
  22 #include "hv-gpci.h"
  23 #include "hv-common.h"
  24
  25 /*
  26  * Example usage:
  27  *  perf stat -e 'hv_gpci/counter_info_version=3,offset=0,length=8,
  28  *                secondary_index=0,starting_index=0xffffffff,request=0x10/' ...
  29  */
  30
  31 /* u32 */
  32 EVENT_DEFINE_RANGE_FORMAT(request, config, 0, 31);
  33 /* u32 */
  34 EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 32, 63);
  35 /* u16 */
  36 EVENT_DEFINE_RANGE_FORMAT(secondary_index, config1, 0, 15);
  37 /* u8 */
  38 EVENT_DEFINE_RANGE_FORMAT(counter_info_version, config1, 16, 23);
  39 /* u8, bytes of data (1-8) */
  40 EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31);
  41 /* u32, byte offset */
  42 EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63);
  43
  44 static struct attribute *format_attrs[] = {
  45         &format_attr_request.attr,
  46         &format_attr_starting_index.attr,
  47         &format_attr_secondary_index.attr,
  48         &format_attr_counter_info_version.attr,
  49
  50         &format_attr_offset.attr,
  51         &format_attr_length.attr,
  52         NULL,
  53 };
  54
  55 static struct attribute_group format_group = {
  56         .name = "format",
  57         .attrs = format_attrs,
  58 };
  59
  60 #define HV_CAPS_ATTR(_name, _format)                            \
  61 static ssize_t _name##_show(struct device *dev,                 \
  62                             struct device_attribute *attr,      \
  63                             char *page)                         \
  64 {                                                               \
  65         struct hv_perf_caps caps;                               \
  66         unsigned long hret = hv_perf_caps_get(&caps);           \
  67         if (hret)                                               \
  68                 return -EIO;                                    \
  69                                                                 \
  70         return sprintf(page, _format, caps._name);              \
  71 }                                                               \
  72 static struct device_attribute hv_caps_attr_##_name = __ATTR_RO(_name)
  73
  74 static ssize_t kernel_version_show(struct device *dev,
  75                                    struct device_attribute *attr,
  76                                    char *page)
  77 {
  78         return sprintf(page, "0x%x\n", COUNTER_INFO_VERSION_CURRENT);
  79 }
  80
  81 static DEVICE_ATTR_RO(kernel_version);
  82 HV_CAPS_ATTR(version, "0x%x\n");
  83 HV_CAPS_ATTR(ga, "%d\n");
  84 HV_CAPS_ATTR(expanded, "%d\n");
  85 HV_CAPS_ATTR(lab, "%d\n");
  86 HV_CAPS_ATTR(collect_privileged, "%d\n");
  87
  88 static struct attribute *interface_attrs[] = {
  89         &dev_attr_kernel_version.attr,
  90         &hv_caps_attr_version.attr,
  91         &hv_caps_attr_ga.attr,
  92         &hv_caps_attr_expanded.attr,
  93         &hv_caps_attr_lab.attr,
  94         &hv_caps_attr_collect_privileged.attr,
  95         NULL,
  96 };
  97
  98 static struct attribute_group interface_group = {
  99         .name = "interface",
 100         .attrs = interface_attrs,
 101 };
 102
 103 static const struct attribute_group *attr_groups[] = {
 104         &format_group,
 105         &interface_group,
 106         NULL,
 107 };
 108
 109 #define GPCI_MAX_DATA_BYTES \
 110         (1024 - sizeof(struct hv_get_perf_counter_info_params))
 111
 112 static unsigned long single_gpci_request(u32 req, u32 starting_index,
 113                 u16 secondary_index, u8 version_in, u32 offset, u8 length,
 114                 u64 *value)
 115 {
 116         unsigned long ret;
 117         size_t i;
 118         u64 count;
 119
 120         struct {
 121                 struct hv_get_perf_counter_info_params params;
 122                 uint8_t bytes[GPCI_MAX_DATA_BYTES];
 123         } __packed __aligned(sizeof(uint64_t)) arg = {
 124                 .params = {
 125                         .counter_request = cpu_to_be32(req),
 126                         .starting_index = cpu_to_be32(starting_index),
 127                         .secondary_index = cpu_to_be16(secondary_index),
 128                         .counter_info_version_in = version_in,
 129                 }
 130         };
 131
 132         ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
 133                         virt_to_phys(&arg), sizeof(arg));
 134         if (ret) {
 135                 pr_devel("hcall failed: 0x%lx\n", ret);
 136                 return ret;
 137         }
 138
 139         /*
 140          * we verify offset and length are within the zeroed buffer at event
 141          * init.
 142          */
 143         count = 0;
 144         for (i = offset; i < offset + length; i++)
 145                 count |= arg.bytes[i] << (i - offset);
 146
 147         *value = count;
 148         return ret;
 149 }
 150
 151 static u64 h_gpci_get_value(struct perf_event *event)
 152 {
 153         u64 count;
 154         unsigned long ret = single_gpci_request(event_get_request(event),
 155                                         event_get_starting_index(event),
 156                                         event_get_secondary_index(event),
 157                                         event_get_counter_info_version(event),
 158                                         event_get_offset(event),
 159                                         event_get_length(event),
 160                                         &count);
 161         if (ret)
 162                 return 0;
 163         return count;
 164 }
 165
 166 static void h_gpci_event_update(struct perf_event *event)
 167 {
 168         s64 prev;
 169         u64 now = h_gpci_get_value(event);
 170         prev = local64_xchg(&event->hw.prev_count, now);
 171         local64_add(now - prev, &event->count);
 172 }
 173
 174 static void h_gpci_event_start(struct perf_event *event, int flags)
 175 {
 176         local64_set(&event->hw.prev_count, h_gpci_get_value(event));
 177 }
 178
 179 static void h_gpci_event_stop(struct perf_event *event, int flags)
 180 {
 181         h_gpci_event_update(event);
 182 }
 183
 184 static int h_gpci_event_add(struct perf_event *event, int flags)
 185 {
 186         if (flags & PERF_EF_START)
 187                 h_gpci_event_start(event, flags);
 188
 189         return 0;
 190 }
 191
 192 static int h_gpci_event_init(struct perf_event *event)
 193 {
 194         u64 count;
 195         u8 length;
 196
 197         /* Not our event */
 198         if (event->attr.type != event->pmu->type)
 199                 return -ENOENT;
 200
 201         /* config2 is unused */
 202         if (event->attr.config2) {
 203                 pr_devel("config2 set when reserved\n");
 204                 return -EINVAL;
 205         }
 206
 207         /* unsupported modes and filters */
 208         if (event->attr.exclude_user   ||
 209             event->attr.exclude_kernel ||
 210             event->attr.exclude_hv     ||
 211             event->attr.exclude_idle   ||
 212             event->attr.exclude_host   ||
 213             event->attr.exclude_guest)
 214                 return -EINVAL;
 215
 216         /* no branch sampling */
 217         if (has_branch_stack(event))
 218                 return -EOPNOTSUPP;
 219
 220         length = event_get_length(event);
 221         if (length < 1 || length > 8) {
 222                 pr_devel("length invalid\n");
 223                 return -EINVAL;
 224         }
 225
 226         /* last byte within the buffer? */
 227         if ((event_get_offset(event) + length) > GPCI_MAX_DATA_BYTES) {
 228                 pr_devel("request outside of buffer: %zu > %zu\n",
 229                                 (size_t)event_get_offset(event) + length,
 230                                 GPCI_MAX_DATA_BYTES);
 231                 return -EINVAL;
 232         }
 233
 234         /* check if the request works... */
 235         if (single_gpci_request(event_get_request(event),
 236                                 event_get_starting_index(event),
 237                                 event_get_secondary_index(event),
 238                                 event_get_counter_info_version(event),
 239                                 event_get_offset(event),
 240                                 length,
 241                                 &count)) {
 242                 pr_devel("gpci hcall failed\n");
 243                 return -EINVAL;
 244         }
 245
 246         return 0;
 247 }
 248
 249 static struct pmu h_gpci_pmu = {
 250         .task_ctx_nr = perf_invalid_context,
 251
 252         .name = "hv_gpci",
 253         .attr_groups = attr_groups,
 254         .event_init  = h_gpci_event_init,
 255         .add         = h_gpci_event_add,
 256         .del         = h_gpci_event_stop,
 257         .start       = h_gpci_event_start,
 258         .stop        = h_gpci_event_stop,
 259         .read        = h_gpci_event_update,
 260 };
 261
 262 static int hv_gpci_init(void)
 263 {
 264         int r;
 265         unsigned long hret;
 266         struct hv_perf_caps caps;
 267
 268         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 269                 pr_debug("not a virtualized system, not enabling\n");
 270                 return -ENODEV;
 271         }
 272
 273         hret = hv_perf_caps_get(&caps);
 274         if (hret) {
 275                 pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
 276                                 hret);
 277                 return -ENODEV;
 278         }
 279
 280         /* sampling not supported */
 281         h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 282
 283         r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
 284         if (r)
 285                 return r;
 286
 287         return 0;
 288 }
 289
 290 device_initcall(hv_gpci_init);