Linux 5.7.6
[linux/fpc-iii.git] / arch / s390 / kernel / perf_cpum_cf.c
blob0eb1d1cc53a88380421468f5daa6ec1f842328e2
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Performance event support for s390x - CPU-measurement Counter Facility
5 * Copyright IBM Corp. 2012, 2019
6 * Author(s): Hendrik Brueckner <brueckner@linux.ibm.com>
7 */
8 #define KMSG_COMPONENT "cpum_cf"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11 #include <linux/kernel.h>
12 #include <linux/kernel_stat.h>
13 #include <linux/percpu.h>
14 #include <linux/notifier.h>
15 #include <linux/init.h>
16 #include <linux/export.h>
17 #include <asm/cpu_mcf.h>
19 static enum cpumf_ctr_set get_counter_set(u64 event)
21 int set = CPUMF_CTR_SET_MAX;
23 if (event < 32)
24 set = CPUMF_CTR_SET_BASIC;
25 else if (event < 64)
26 set = CPUMF_CTR_SET_USER;
27 else if (event < 128)
28 set = CPUMF_CTR_SET_CRYPTO;
29 else if (event < 288)
30 set = CPUMF_CTR_SET_EXT;
31 else if (event >= 448 && event < 496)
32 set = CPUMF_CTR_SET_MT_DIAG;
34 return set;
37 static int validate_ctr_version(const struct hw_perf_event *hwc)
39 struct cpu_cf_events *cpuhw;
40 int err = 0;
41 u16 mtdiag_ctl;
43 cpuhw = &get_cpu_var(cpu_cf_events);
45 /* check required version for counter sets */
46 switch (hwc->config_base) {
47 case CPUMF_CTR_SET_BASIC:
48 case CPUMF_CTR_SET_USER:
49 if (cpuhw->info.cfvn < 1)
50 err = -EOPNOTSUPP;
51 break;
52 case CPUMF_CTR_SET_CRYPTO:
53 if ((cpuhw->info.csvn >= 1 && cpuhw->info.csvn <= 5 &&
54 hwc->config > 79) ||
55 (cpuhw->info.csvn >= 6 && hwc->config > 83))
56 err = -EOPNOTSUPP;
57 break;
58 case CPUMF_CTR_SET_EXT:
59 if (cpuhw->info.csvn < 1)
60 err = -EOPNOTSUPP;
61 if ((cpuhw->info.csvn == 1 && hwc->config > 159) ||
62 (cpuhw->info.csvn == 2 && hwc->config > 175) ||
63 (cpuhw->info.csvn >= 3 && cpuhw->info.csvn <= 5
64 && hwc->config > 255) ||
65 (cpuhw->info.csvn >= 6 && hwc->config > 287))
66 err = -EOPNOTSUPP;
67 break;
68 case CPUMF_CTR_SET_MT_DIAG:
69 if (cpuhw->info.csvn <= 3)
70 err = -EOPNOTSUPP;
72 * MT-diagnostic counters are read-only. The counter set
73 * is automatically enabled and activated on all CPUs with
74 * multithreading (SMT). Deactivation of multithreading
75 * also disables the counter set. State changes are ignored
76 * by lcctl(). Because Linux controls SMT enablement through
77 * a kernel parameter only, the counter set is either disabled
78 * or enabled and active.
80 * Thus, the counters can only be used if SMT is on and the
81 * counter set is enabled and active.
83 mtdiag_ctl = cpumf_ctr_ctl[CPUMF_CTR_SET_MT_DIAG];
84 if (!((cpuhw->info.auth_ctl & mtdiag_ctl) &&
85 (cpuhw->info.enable_ctl & mtdiag_ctl) &&
86 (cpuhw->info.act_ctl & mtdiag_ctl)))
87 err = -EOPNOTSUPP;
88 break;
91 put_cpu_var(cpu_cf_events);
92 return err;
95 static int validate_ctr_auth(const struct hw_perf_event *hwc)
97 struct cpu_cf_events *cpuhw;
98 u64 ctrs_state;
99 int err = 0;
101 cpuhw = &get_cpu_var(cpu_cf_events);
103 /* Check authorization for cpu counter sets.
104 * If the particular CPU counter set is not authorized,
105 * return with -ENOENT in order to fall back to other
106 * PMUs that might suffice the event request.
108 ctrs_state = cpumf_ctr_ctl[hwc->config_base];
109 if (!(ctrs_state & cpuhw->info.auth_ctl))
110 err = -ENOENT;
112 put_cpu_var(cpu_cf_events);
113 return err;
117 * Change the CPUMF state to active.
118 * Enable and activate the CPU-counter sets according
119 * to the per-cpu control state.
121 static void cpumf_pmu_enable(struct pmu *pmu)
123 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
124 int err;
126 if (cpuhw->flags & PMU_F_ENABLED)
127 return;
129 err = lcctl(cpuhw->state);
130 if (err) {
131 pr_err("Enabling the performance measuring unit "
132 "failed with rc=%x\n", err);
133 return;
136 cpuhw->flags |= PMU_F_ENABLED;
140 * Change the CPUMF state to inactive.
141 * Disable and enable (inactive) the CPU-counter sets according
142 * to the per-cpu control state.
144 static void cpumf_pmu_disable(struct pmu *pmu)
146 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
147 int err;
148 u64 inactive;
150 if (!(cpuhw->flags & PMU_F_ENABLED))
151 return;
153 inactive = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1);
154 err = lcctl(inactive);
155 if (err) {
156 pr_err("Disabling the performance measuring unit "
157 "failed with rc=%x\n", err);
158 return;
161 cpuhw->flags &= ~PMU_F_ENABLED;
165 /* Number of perf events counting hardware events */
166 static atomic_t num_events = ATOMIC_INIT(0);
167 /* Used to avoid races in calling reserve/release_cpumf_hardware */
168 static DEFINE_MUTEX(pmc_reserve_mutex);
170 /* Release the PMU if event is the last perf event */
171 static void hw_perf_event_destroy(struct perf_event *event)
173 if (!atomic_add_unless(&num_events, -1, 1)) {
174 mutex_lock(&pmc_reserve_mutex);
175 if (atomic_dec_return(&num_events) == 0)
176 __kernel_cpumcf_end();
177 mutex_unlock(&pmc_reserve_mutex);
181 /* CPUMF <-> perf event mappings for kernel+userspace (basic set) */
182 static const int cpumf_generic_events_basic[] = {
183 [PERF_COUNT_HW_CPU_CYCLES] = 0,
184 [PERF_COUNT_HW_INSTRUCTIONS] = 1,
185 [PERF_COUNT_HW_CACHE_REFERENCES] = -1,
186 [PERF_COUNT_HW_CACHE_MISSES] = -1,
187 [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1,
188 [PERF_COUNT_HW_BRANCH_MISSES] = -1,
189 [PERF_COUNT_HW_BUS_CYCLES] = -1,
191 /* CPUMF <-> perf event mappings for userspace (problem-state set) */
192 static const int cpumf_generic_events_user[] = {
193 [PERF_COUNT_HW_CPU_CYCLES] = 32,
194 [PERF_COUNT_HW_INSTRUCTIONS] = 33,
195 [PERF_COUNT_HW_CACHE_REFERENCES] = -1,
196 [PERF_COUNT_HW_CACHE_MISSES] = -1,
197 [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1,
198 [PERF_COUNT_HW_BRANCH_MISSES] = -1,
199 [PERF_COUNT_HW_BUS_CYCLES] = -1,
202 static int __hw_perf_event_init(struct perf_event *event, unsigned int type)
204 struct perf_event_attr *attr = &event->attr;
205 struct hw_perf_event *hwc = &event->hw;
206 enum cpumf_ctr_set set;
207 int err = 0;
208 u64 ev;
210 switch (type) {
211 case PERF_TYPE_RAW:
212 /* Raw events are used to access counters directly,
213 * hence do not permit excludes */
214 if (attr->exclude_kernel || attr->exclude_user ||
215 attr->exclude_hv)
216 return -EOPNOTSUPP;
217 ev = attr->config;
218 break;
220 case PERF_TYPE_HARDWARE:
221 if (is_sampling_event(event)) /* No sampling support */
222 return -ENOENT;
223 ev = attr->config;
224 /* Count user space (problem-state) only */
225 if (!attr->exclude_user && attr->exclude_kernel) {
226 if (ev >= ARRAY_SIZE(cpumf_generic_events_user))
227 return -EOPNOTSUPP;
228 ev = cpumf_generic_events_user[ev];
230 /* No support for kernel space counters only */
231 } else if (!attr->exclude_kernel && attr->exclude_user) {
232 return -EOPNOTSUPP;
234 /* Count user and kernel space */
235 } else {
236 if (ev >= ARRAY_SIZE(cpumf_generic_events_basic))
237 return -EOPNOTSUPP;
238 ev = cpumf_generic_events_basic[ev];
240 break;
242 default:
243 return -ENOENT;
246 if (ev == -1)
247 return -ENOENT;
249 if (ev > PERF_CPUM_CF_MAX_CTR)
250 return -ENOENT;
252 /* Obtain the counter set to which the specified counter belongs */
253 set = get_counter_set(ev);
254 switch (set) {
255 case CPUMF_CTR_SET_BASIC:
256 case CPUMF_CTR_SET_USER:
257 case CPUMF_CTR_SET_CRYPTO:
258 case CPUMF_CTR_SET_EXT:
259 case CPUMF_CTR_SET_MT_DIAG:
261 * Use the hardware perf event structure to store the
262 * counter number in the 'config' member and the counter
263 * set number in the 'config_base'. The counter set number
264 * is then later used to enable/disable the counter(s).
266 hwc->config = ev;
267 hwc->config_base = set;
268 break;
269 case CPUMF_CTR_SET_MAX:
270 /* The counter could not be associated to a counter set */
271 return -EINVAL;
274 /* Initialize for using the CPU-measurement counter facility */
275 if (!atomic_inc_not_zero(&num_events)) {
276 mutex_lock(&pmc_reserve_mutex);
277 if (atomic_read(&num_events) == 0 && __kernel_cpumcf_begin())
278 err = -EBUSY;
279 else
280 atomic_inc(&num_events);
281 mutex_unlock(&pmc_reserve_mutex);
283 if (err)
284 return err;
285 event->destroy = hw_perf_event_destroy;
287 /* Finally, validate version and authorization of the counter set */
288 err = validate_ctr_auth(hwc);
289 if (!err)
290 err = validate_ctr_version(hwc);
292 return err;
295 static int cpumf_pmu_event_init(struct perf_event *event)
297 unsigned int type = event->attr.type;
298 int err;
300 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_RAW)
301 err = __hw_perf_event_init(event, type);
302 else if (event->pmu->type == type)
303 /* Registered as unknown PMU */
304 err = __hw_perf_event_init(event, PERF_TYPE_RAW);
305 else
306 return -ENOENT;
308 if (unlikely(err) && event->destroy)
309 event->destroy(event);
311 return err;
314 static int hw_perf_event_reset(struct perf_event *event)
316 u64 prev, new;
317 int err;
319 do {
320 prev = local64_read(&event->hw.prev_count);
321 err = ecctr(event->hw.config, &new);
322 if (err) {
323 if (err != 3)
324 break;
325 /* The counter is not (yet) available. This
326 * might happen if the counter set to which
327 * this counter belongs is in the disabled
328 * state.
330 new = 0;
332 } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
334 return err;
337 static void hw_perf_event_update(struct perf_event *event)
339 u64 prev, new, delta;
340 int err;
342 do {
343 prev = local64_read(&event->hw.prev_count);
344 err = ecctr(event->hw.config, &new);
345 if (err)
346 return;
347 } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
349 delta = (prev <= new) ? new - prev
350 : (-1ULL - prev) + new + 1; /* overflow */
351 local64_add(delta, &event->count);
354 static void cpumf_pmu_read(struct perf_event *event)
356 if (event->hw.state & PERF_HES_STOPPED)
357 return;
359 hw_perf_event_update(event);
362 static void cpumf_pmu_start(struct perf_event *event, int flags)
364 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
365 struct hw_perf_event *hwc = &event->hw;
367 if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
368 return;
370 if (WARN_ON_ONCE(hwc->config == -1))
371 return;
373 if (flags & PERF_EF_RELOAD)
374 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
376 hwc->state = 0;
378 /* (Re-)enable and activate the counter set */
379 ctr_set_enable(&cpuhw->state, hwc->config_base);
380 ctr_set_start(&cpuhw->state, hwc->config_base);
382 /* The counter set to which this counter belongs can be already active.
383 * Because all counters in a set are active, the event->hw.prev_count
384 * needs to be synchronized. At this point, the counter set can be in
385 * the inactive or disabled state.
387 hw_perf_event_reset(event);
389 /* increment refcount for this counter set */
390 atomic_inc(&cpuhw->ctr_set[hwc->config_base]);
393 static void cpumf_pmu_stop(struct perf_event *event, int flags)
395 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
396 struct hw_perf_event *hwc = &event->hw;
398 if (!(hwc->state & PERF_HES_STOPPED)) {
399 /* Decrement reference count for this counter set and if this
400 * is the last used counter in the set, clear activation
401 * control and set the counter set state to inactive.
403 if (!atomic_dec_return(&cpuhw->ctr_set[hwc->config_base]))
404 ctr_set_stop(&cpuhw->state, hwc->config_base);
405 event->hw.state |= PERF_HES_STOPPED;
408 if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
409 hw_perf_event_update(event);
410 event->hw.state |= PERF_HES_UPTODATE;
414 static int cpumf_pmu_add(struct perf_event *event, int flags)
416 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
418 /* Check authorization for the counter set to which this
419 * counter belongs.
420 * For group events transaction, the authorization check is
421 * done in cpumf_pmu_commit_txn().
423 if (!(cpuhw->txn_flags & PERF_PMU_TXN_ADD))
424 if (validate_ctr_auth(&event->hw))
425 return -ENOENT;
427 ctr_set_enable(&cpuhw->state, event->hw.config_base);
428 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
430 if (flags & PERF_EF_START)
431 cpumf_pmu_start(event, PERF_EF_RELOAD);
433 perf_event_update_userpage(event);
435 return 0;
438 static void cpumf_pmu_del(struct perf_event *event, int flags)
440 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
442 cpumf_pmu_stop(event, PERF_EF_UPDATE);
444 /* Check if any counter in the counter set is still used. If not used,
445 * change the counter set to the disabled state. This also clears the
446 * content of all counters in the set.
448 * When a new perf event has been added but not yet started, this can
449 * clear enable control and resets all counters in a set. Therefore,
450 * cpumf_pmu_start() always has to reenable a counter set.
452 if (!atomic_read(&cpuhw->ctr_set[event->hw.config_base]))
453 ctr_set_disable(&cpuhw->state, event->hw.config_base);
455 perf_event_update_userpage(event);
459 * Start group events scheduling transaction.
460 * Set flags to perform a single test at commit time.
462 * We only support PERF_PMU_TXN_ADD transactions. Save the
463 * transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD
464 * transactions.
466 static void cpumf_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
468 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
470 WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */
472 cpuhw->txn_flags = txn_flags;
473 if (txn_flags & ~PERF_PMU_TXN_ADD)
474 return;
476 perf_pmu_disable(pmu);
477 cpuhw->tx_state = cpuhw->state;
481 * Stop and cancel a group events scheduling tranctions.
482 * Assumes cpumf_pmu_del() is called for each successful added
483 * cpumf_pmu_add() during the transaction.
485 static void cpumf_pmu_cancel_txn(struct pmu *pmu)
487 unsigned int txn_flags;
488 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
490 WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
492 txn_flags = cpuhw->txn_flags;
493 cpuhw->txn_flags = 0;
494 if (txn_flags & ~PERF_PMU_TXN_ADD)
495 return;
497 WARN_ON(cpuhw->tx_state != cpuhw->state);
499 perf_pmu_enable(pmu);
503 * Commit the group events scheduling transaction. On success, the
504 * transaction is closed. On error, the transaction is kept open
505 * until cpumf_pmu_cancel_txn() is called.
507 static int cpumf_pmu_commit_txn(struct pmu *pmu)
509 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
510 u64 state;
512 WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
514 if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) {
515 cpuhw->txn_flags = 0;
516 return 0;
519 /* check if the updated state can be scheduled */
520 state = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1);
521 state >>= CPUMF_LCCTL_ENABLE_SHIFT;
522 if ((state & cpuhw->info.auth_ctl) != state)
523 return -ENOENT;
525 cpuhw->txn_flags = 0;
526 perf_pmu_enable(pmu);
527 return 0;
530 /* Performance monitoring unit for s390x */
531 static struct pmu cpumf_pmu = {
532 .task_ctx_nr = perf_sw_context,
533 .capabilities = PERF_PMU_CAP_NO_INTERRUPT,
534 .pmu_enable = cpumf_pmu_enable,
535 .pmu_disable = cpumf_pmu_disable,
536 .event_init = cpumf_pmu_event_init,
537 .add = cpumf_pmu_add,
538 .del = cpumf_pmu_del,
539 .start = cpumf_pmu_start,
540 .stop = cpumf_pmu_stop,
541 .read = cpumf_pmu_read,
542 .start_txn = cpumf_pmu_start_txn,
543 .commit_txn = cpumf_pmu_commit_txn,
544 .cancel_txn = cpumf_pmu_cancel_txn,
547 static int __init cpumf_pmu_init(void)
549 int rc;
551 if (!kernel_cpumcf_avail())
552 return -ENODEV;
554 cpumf_pmu.attr_groups = cpumf_cf_event_group();
555 rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", -1);
556 if (rc)
557 pr_err("Registering the cpum_cf PMU failed with rc=%i\n", rc);
558 return rc;
560 subsys_initcall(cpumf_pmu_init);