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 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 = hv_gpci_event_attrs, 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 struct attribute_group cpumask_attr_group = { 130 .attrs = cpumask_attrs, 131 }; 132 133 static 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 |= arg->bytes[i] << (i - offset); 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; 333 334 hv_gpci_assert_offsets_correct(); 335 336 if (!firmware_has_feature(FW_FEATURE_LPAR)) { 337 pr_debug("not a virtualized system, not enabling\n"); 338 return -ENODEV; 339 } 340 341 hret = hv_perf_caps_get(&caps); 342 if (hret) { 343 pr_debug("could not obtain capabilities, not enabling, rc=%ld\n", 344 hret); 345 return -ENODEV; 346 } 347 348 /* init cpuhotplug */ 349 r = hv_gpci_cpu_hotplug_init(); 350 if (r) 351 return r; 352 353 /* sampling not supported */ 354 h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT; 355 356 r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1); 357 if (r) 358 return r; 359 360 return 0; 361 } 362 363 device_initcall(hv_gpci_init); 364