1 // SPDX-License-Identifier: GPL-2.0
3 * Performance event support framework for SuperH hardware counters.
5 * Copyright (C) 2009 Paul Mundt
7 * Heavily based on the x86 and PowerPC implementations.
10 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
11 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
12 * Copyright (C) 2009 Jaswinder Singh Rajput
13 * Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
14 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra
15 * Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
18 * Copyright 2008-2009 Paul Mackerras, IBM Corporation.
20 #include <linux/kernel.h>
21 #include <linux/init.h>
23 #include <linux/irq.h>
24 #include <linux/perf_event.h>
25 #include <linux/export.h>
26 #include <asm/processor.h>
28 struct cpu_hw_events {
29 struct perf_event *events[MAX_HWEVENTS];
30 unsigned long used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
31 unsigned long active_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
34 DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
36 static struct sh_pmu *sh_pmu __read_mostly;
38 /* Number of perf_events counting hardware events */
39 static atomic_t num_events;
40 /* Used to avoid races in calling reserve/release_pmc_hardware */
41 static DEFINE_MUTEX(pmc_reserve_mutex);
44 * Stub these out for now, do something more profound later.
46 int reserve_pmc_hardware(void)
51 void release_pmc_hardware(void)
55 static inline int sh_pmu_initialized(void)
60 const char *perf_pmu_name(void)
67 EXPORT_SYMBOL_GPL(perf_pmu_name);
69 int perf_num_counters(void)
74 return sh_pmu->num_events;
76 EXPORT_SYMBOL_GPL(perf_num_counters);
79 * Release the PMU if this is the last perf_event.
81 static void hw_perf_event_destroy(struct perf_event *event)
83 if (!atomic_add_unless(&num_events, -1, 1)) {
84 mutex_lock(&pmc_reserve_mutex);
85 if (atomic_dec_return(&num_events) == 0)
86 release_pmc_hardware();
87 mutex_unlock(&pmc_reserve_mutex);
91 static int hw_perf_cache_event(int config, int *evp)
93 unsigned long type, op, result;
96 if (!sh_pmu->cache_events)
100 type = config & 0xff;
101 op = (config >> 8) & 0xff;
102 result = (config >> 16) & 0xff;
104 if (type >= PERF_COUNT_HW_CACHE_MAX ||
105 op >= PERF_COUNT_HW_CACHE_OP_MAX ||
106 result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
109 ev = (*sh_pmu->cache_events)[type][op][result];
118 static int __hw_perf_event_init(struct perf_event *event)
120 struct perf_event_attr *attr = &event->attr;
121 struct hw_perf_event *hwc = &event->hw;
125 if (!sh_pmu_initialized())
129 * See if we need to reserve the counter.
131 * If no events are currently in use, then we have to take a
132 * mutex to ensure that we don't race with another task doing
133 * reserve_pmc_hardware or release_pmc_hardware.
136 if (!atomic_inc_not_zero(&num_events)) {
137 mutex_lock(&pmc_reserve_mutex);
138 if (atomic_read(&num_events) == 0 &&
139 reserve_pmc_hardware())
142 atomic_inc(&num_events);
143 mutex_unlock(&pmc_reserve_mutex);
149 event->destroy = hw_perf_event_destroy;
151 switch (attr->type) {
153 config = attr->config & sh_pmu->raw_event_mask;
155 case PERF_TYPE_HW_CACHE:
156 err = hw_perf_cache_event(attr->config, &config);
160 case PERF_TYPE_HARDWARE:
161 if (attr->config >= sh_pmu->max_events)
164 config = sh_pmu->event_map(attr->config);
171 hwc->config |= config;
176 static void sh_perf_event_update(struct perf_event *event,
177 struct hw_perf_event *hwc, int idx)
179 u64 prev_raw_count, new_raw_count;
184 * Depending on the counter configuration, they may or may not
185 * be chained, in which case the previous counter value can be
186 * updated underneath us if the lower-half overflows.
188 * Our tactic to handle this is to first atomically read and
189 * exchange a new raw count - then add that new-prev delta
190 * count to the generic counter atomically.
192 * As there is no interrupt associated with the overflow events,
193 * this is the simplest approach for maintaining consistency.
196 prev_raw_count = local64_read(&hwc->prev_count);
197 new_raw_count = sh_pmu->read(idx);
199 if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
200 new_raw_count) != prev_raw_count)
204 * Now we have the new raw value and have updated the prev
205 * timestamp already. We can now calculate the elapsed delta
206 * (counter-)time and add that to the generic counter.
208 * Careful, not all hw sign-extends above the physical width
211 delta = (new_raw_count << shift) - (prev_raw_count << shift);
214 local64_add(delta, &event->count);
217 static void sh_pmu_stop(struct perf_event *event, int flags)
219 struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
220 struct hw_perf_event *hwc = &event->hw;
223 if (!(event->hw.state & PERF_HES_STOPPED)) {
224 sh_pmu->disable(hwc, idx);
225 cpuc->events[idx] = NULL;
226 event->hw.state |= PERF_HES_STOPPED;
229 if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) {
230 sh_perf_event_update(event, &event->hw, idx);
231 event->hw.state |= PERF_HES_UPTODATE;
235 static void sh_pmu_start(struct perf_event *event, int flags)
237 struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
238 struct hw_perf_event *hwc = &event->hw;
241 if (WARN_ON_ONCE(idx == -1))
244 if (flags & PERF_EF_RELOAD)
245 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
247 cpuc->events[idx] = event;
249 sh_pmu->enable(hwc, idx);
252 static void sh_pmu_del(struct perf_event *event, int flags)
254 struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
256 sh_pmu_stop(event, PERF_EF_UPDATE);
257 __clear_bit(event->hw.idx, cpuc->used_mask);
259 perf_event_update_userpage(event);
262 static int sh_pmu_add(struct perf_event *event, int flags)
264 struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
265 struct hw_perf_event *hwc = &event->hw;
269 perf_pmu_disable(event->pmu);
271 if (__test_and_set_bit(idx, cpuc->used_mask)) {
272 idx = find_first_zero_bit(cpuc->used_mask, sh_pmu->num_events);
273 if (idx == sh_pmu->num_events)
276 __set_bit(idx, cpuc->used_mask);
280 sh_pmu->disable(hwc, idx);
282 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
283 if (flags & PERF_EF_START)
284 sh_pmu_start(event, PERF_EF_RELOAD);
286 perf_event_update_userpage(event);
289 perf_pmu_enable(event->pmu);
293 static void sh_pmu_read(struct perf_event *event)
295 sh_perf_event_update(event, &event->hw, event->hw.idx);
298 static int sh_pmu_event_init(struct perf_event *event)
302 /* does not support taken branch sampling */
303 if (has_branch_stack(event))
306 switch (event->attr.type) {
308 case PERF_TYPE_HW_CACHE:
309 case PERF_TYPE_HARDWARE:
310 err = __hw_perf_event_init(event);
319 event->destroy(event);
325 static void sh_pmu_enable(struct pmu *pmu)
327 if (!sh_pmu_initialized())
330 sh_pmu->enable_all();
333 static void sh_pmu_disable(struct pmu *pmu)
335 if (!sh_pmu_initialized())
338 sh_pmu->disable_all();
341 static struct pmu pmu = {
342 .pmu_enable = sh_pmu_enable,
343 .pmu_disable = sh_pmu_disable,
344 .event_init = sh_pmu_event_init,
347 .start = sh_pmu_start,
352 static int sh_pmu_prepare_cpu(unsigned int cpu)
354 struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
356 memset(cpuhw, 0, sizeof(struct cpu_hw_events));
360 int register_sh_pmu(struct sh_pmu *_pmu)
366 pr_info("Performance Events: %s support registered\n", _pmu->name);
369 * All of the on-chip counters are "limited", in that they have
370 * no interrupts, and are therefore unable to do sampling without
371 * further work and timer assistance.
373 pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
375 WARN_ON(_pmu->num_events > MAX_HWEVENTS);
377 perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
378 cpuhp_setup_state(CPUHP_PERF_SUPERH, "PERF_SUPERH", sh_pmu_prepare_cpu,