1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * ARM CoreSight Architecture PMU driver.
4  *
5  * This driver adds support for uncore PMU based on ARM CoreSight Performance
6  * Monitoring Unit Architecture. The PMU is accessible via MMIO registers and
7  * like other uncore PMUs, it does not support process specific events and
8  * cannot be used in sampling mode.
9  *
10  * This code is based on other uncore PMUs like ARM DSU PMU. It provides a
11  * generic implementation to operate the PMU according to CoreSight PMU
12  * architecture and ACPI ARM PMU table (APMT) documents below:
13  *   - ARM CoreSight PMU architecture document number: ARM IHI 0091 A.a-00bet0.
14  *   - APMT document number: ARM DEN0117.
15  *
16  * The user should refer to the vendor technical documentation to get details
17  * about the supported events.
18  *
19  * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
20  *
21  */
22 
23 #include <linux/acpi.h>
24 #include <linux/cacheinfo.h>
25 #include <linux/ctype.h>
26 #include <linux/interrupt.h>
27 #include <linux/io-64-nonatomic-lo-hi.h>
28 #include <linux/module.h>
29 #include <linux/perf_event.h>
30 #include <linux/platform_device.h>
31 
32 #include "arm_cspmu.h"
33 #include "nvidia_cspmu.h"
34 
35 #define PMUNAME "arm_cspmu"
36 #define DRVNAME "arm-cs-arch-pmu"
37 
38 #define ARM_CSPMU_CPUMASK_ATTR(_name, _config)			\
39 	ARM_CSPMU_EXT_ATTR(_name, arm_cspmu_cpumask_show,	\
40 				(unsigned long)_config)
41 
42 /*
43  * CoreSight PMU Arch register offsets.
44  */
45 #define PMEVCNTR_LO					0x0
46 #define PMEVCNTR_HI					0x4
47 #define PMEVTYPER					0x400
48 #define PMCCFILTR					0x47C
49 #define PMEVFILTR					0xA00
50 #define PMCNTENSET					0xC00
51 #define PMCNTENCLR					0xC20
52 #define PMINTENSET					0xC40
53 #define PMINTENCLR					0xC60
54 #define PMOVSCLR					0xC80
55 #define PMOVSSET					0xCC0
56 #define PMCFGR						0xE00
57 #define PMCR						0xE04
58 #define PMIIDR						0xE08
59 
60 /* PMCFGR register field */
61 #define PMCFGR_NCG					GENMASK(31, 28)
62 #define PMCFGR_HDBG					BIT(24)
63 #define PMCFGR_TRO					BIT(23)
64 #define PMCFGR_SS					BIT(22)
65 #define PMCFGR_FZO					BIT(21)
66 #define PMCFGR_MSI					BIT(20)
67 #define PMCFGR_UEN					BIT(19)
68 #define PMCFGR_NA					BIT(17)
69 #define PMCFGR_EX					BIT(16)
70 #define PMCFGR_CCD					BIT(15)
71 #define PMCFGR_CC					BIT(14)
72 #define PMCFGR_SIZE					GENMASK(13, 8)
73 #define PMCFGR_N					GENMASK(7, 0)
74 
75 /* PMCR register field */
76 #define PMCR_TRO					BIT(11)
77 #define PMCR_HDBG					BIT(10)
78 #define PMCR_FZO					BIT(9)
79 #define PMCR_NA						BIT(8)
80 #define PMCR_DP						BIT(5)
81 #define PMCR_X						BIT(4)
82 #define PMCR_D						BIT(3)
83 #define PMCR_C						BIT(2)
84 #define PMCR_P						BIT(1)
85 #define PMCR_E						BIT(0)
86 
87 /* Each SET/CLR register supports up to 32 counters. */
88 #define ARM_CSPMU_SET_CLR_COUNTER_SHIFT		5
89 #define ARM_CSPMU_SET_CLR_COUNTER_NUM		\
90 	(1 << ARM_CSPMU_SET_CLR_COUNTER_SHIFT)
91 
92 /* Convert counter idx into SET/CLR register number. */
93 #define COUNTER_TO_SET_CLR_ID(idx)			\
94 	(idx >> ARM_CSPMU_SET_CLR_COUNTER_SHIFT)
95 
96 /* Convert counter idx into SET/CLR register bit. */
97 #define COUNTER_TO_SET_CLR_BIT(idx)			\
98 	(idx & (ARM_CSPMU_SET_CLR_COUNTER_NUM - 1))
99 
100 #define ARM_CSPMU_ACTIVE_CPU_MASK		0x0
101 #define ARM_CSPMU_ASSOCIATED_CPU_MASK		0x1
102 
103 /* Check and use default if implementer doesn't provide attribute callback */
104 #define CHECK_DEFAULT_IMPL_OPS(ops, callback)			\
105 	do {							\
106 		if (!ops->callback)				\
107 			ops->callback = arm_cspmu_ ## callback;	\
108 	} while (0)
109 
110 /*
111  * Maximum poll count for reading counter value using high-low-high sequence.
112  */
113 #define HILOHI_MAX_POLL	1000
114 
115 /* JEDEC-assigned JEP106 identification code */
116 #define ARM_CSPMU_IMPL_ID_NVIDIA		0x36B
117 
118 static unsigned long arm_cspmu_cpuhp_state;
119 
120 static struct acpi_apmt_node *arm_cspmu_apmt_node(struct device *dev)
121 {
122 	return *(struct acpi_apmt_node **)dev_get_platdata(dev);
123 }
124 
125 /*
126  * In CoreSight PMU architecture, all of the MMIO registers are 32-bit except
127  * counter register. The counter register can be implemented as 32-bit or 64-bit
128  * register depending on the value of PMCFGR.SIZE field. For 64-bit access,
129  * single-copy 64-bit atomic support is implementation defined. APMT node flag
130  * is used to identify if the PMU supports 64-bit single copy atomic. If 64-bit
131  * single copy atomic is not supported, the driver treats the register as a pair
132  * of 32-bit register.
133  */
134 
135 /*
136  * Read 64-bit register as a pair of 32-bit registers using hi-lo-hi sequence.
137  */
138 static u64 read_reg64_hilohi(const void __iomem *addr, u32 max_poll_count)
139 {
140 	u32 val_lo, val_hi;
141 	u64 val;
142 
143 	/* Use high-low-high sequence to avoid tearing */
144 	do {
145 		if (max_poll_count-- == 0) {
146 			pr_err("ARM CSPMU: timeout hi-low-high sequence\n");
147 			return 0;
148 		}
149 
150 		val_hi = readl(addr + 4);
151 		val_lo = readl(addr);
152 	} while (val_hi != readl(addr + 4));
153 
154 	val = (((u64)val_hi << 32) | val_lo);
155 
156 	return val;
157 }
158 
159 /* Check if cycle counter is supported. */
160 static inline bool supports_cycle_counter(const struct arm_cspmu *cspmu)
161 {
162 	return (cspmu->pmcfgr & PMCFGR_CC);
163 }
164 
165 /* Get counter size, which is (PMCFGR_SIZE + 1). */
166 static inline u32 counter_size(const struct arm_cspmu *cspmu)
167 {
168 	return FIELD_GET(PMCFGR_SIZE, cspmu->pmcfgr) + 1;
169 }
170 
171 /* Get counter mask. */
172 static inline u64 counter_mask(const struct arm_cspmu *cspmu)
173 {
174 	return GENMASK_ULL(counter_size(cspmu) - 1, 0);
175 }
176 
177 /* Check if counter is implemented as 64-bit register. */
178 static inline bool use_64b_counter_reg(const struct arm_cspmu *cspmu)
179 {
180 	return (counter_size(cspmu) > 32);
181 }
182 
183 ssize_t arm_cspmu_sysfs_event_show(struct device *dev,
184 				struct device_attribute *attr, char *buf)
185 {
186 	struct perf_pmu_events_attr *pmu_attr;
187 
188 	pmu_attr = container_of(attr, typeof(*pmu_attr), attr);
189 	return sysfs_emit(buf, "event=0x%llx\n", pmu_attr->id);
190 }
191 EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_event_show);
192 
193 /* Default event list. */
194 static struct attribute *arm_cspmu_event_attrs[] = {
195 	ARM_CSPMU_EVENT_ATTR(cycles, ARM_CSPMU_EVT_CYCLES_DEFAULT),
196 	NULL,
197 };
198 
199 static struct attribute **
200 arm_cspmu_get_event_attrs(const struct arm_cspmu *cspmu)
201 {
202 	struct attribute **attrs;
203 
204 	attrs = devm_kmemdup(cspmu->dev, arm_cspmu_event_attrs,
205 		sizeof(arm_cspmu_event_attrs), GFP_KERNEL);
206 
207 	return attrs;
208 }
209 
210 static umode_t
211 arm_cspmu_event_attr_is_visible(struct kobject *kobj,
212 				struct attribute *attr, int unused)
213 {
214 	struct device *dev = kobj_to_dev(kobj);
215 	struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));
216 	struct perf_pmu_events_attr *eattr;
217 
218 	eattr = container_of(attr, typeof(*eattr), attr.attr);
219 
220 	/* Hide cycle event if not supported */
221 	if (!supports_cycle_counter(cspmu) &&
222 	    eattr->id == ARM_CSPMU_EVT_CYCLES_DEFAULT)
223 		return 0;
224 
225 	return attr->mode;
226 }
227 
228 ssize_t arm_cspmu_sysfs_format_show(struct device *dev,
229 				struct device_attribute *attr,
230 				char *buf)
231 {
232 	struct dev_ext_attribute *eattr =
233 		container_of(attr, struct dev_ext_attribute, attr);
234 	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
235 }
236 EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_format_show);
237 
238 static struct attribute *arm_cspmu_format_attrs[] = {
239 	ARM_CSPMU_FORMAT_EVENT_ATTR,
240 	ARM_CSPMU_FORMAT_FILTER_ATTR,
241 	NULL,
242 };
243 
244 static struct attribute **
245 arm_cspmu_get_format_attrs(const struct arm_cspmu *cspmu)
246 {
247 	struct attribute **attrs;
248 
249 	attrs = devm_kmemdup(cspmu->dev, arm_cspmu_format_attrs,
250 		sizeof(arm_cspmu_format_attrs), GFP_KERNEL);
251 
252 	return attrs;
253 }
254 
255 static u32 arm_cspmu_event_type(const struct perf_event *event)
256 {
257 	return event->attr.config & ARM_CSPMU_EVENT_MASK;
258 }
259 
260 static bool arm_cspmu_is_cycle_counter_event(const struct perf_event *event)
261 {
262 	return (event->attr.config == ARM_CSPMU_EVT_CYCLES_DEFAULT);
263 }
264 
265 static u32 arm_cspmu_event_filter(const struct perf_event *event)
266 {
267 	return event->attr.config1 & ARM_CSPMU_FILTER_MASK;
268 }
269 
270 static ssize_t arm_cspmu_identifier_show(struct device *dev,
271 					 struct device_attribute *attr,
272 					 char *page)
273 {
274 	struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));
275 
276 	return sysfs_emit(page, "%s\n", cspmu->identifier);
277 }
278 
279 static struct device_attribute arm_cspmu_identifier_attr =
280 	__ATTR(identifier, 0444, arm_cspmu_identifier_show, NULL);
281 
282 static struct attribute *arm_cspmu_identifier_attrs[] = {
283 	&arm_cspmu_identifier_attr.attr,
284 	NULL,
285 };
286 
287 static struct attribute_group arm_cspmu_identifier_attr_group = {
288 	.attrs = arm_cspmu_identifier_attrs,
289 };
290 
291 static const char *arm_cspmu_get_identifier(const struct arm_cspmu *cspmu)
292 {
293 	const char *identifier =
294 		devm_kasprintf(cspmu->dev, GFP_KERNEL, "%x",
295 			       cspmu->impl.pmiidr);
296 	return identifier;
297 }
298 
299 static const char *arm_cspmu_type_str[ACPI_APMT_NODE_TYPE_COUNT] = {
300 	"mc",
301 	"smmu",
302 	"pcie",
303 	"acpi",
304 	"cache",
305 };
306 
307 static const char *arm_cspmu_get_name(const struct arm_cspmu *cspmu)
308 {
309 	struct device *dev;
310 	struct acpi_apmt_node *apmt_node;
311 	u8 pmu_type;
312 	char *name;
313 	char acpi_hid_string[ACPI_ID_LEN] = { 0 };
314 	static atomic_t pmu_idx[ACPI_APMT_NODE_TYPE_COUNT] = { 0 };
315 
316 	dev = cspmu->dev;
317 	apmt_node = arm_cspmu_apmt_node(dev);
318 	pmu_type = apmt_node->type;
319 
320 	if (pmu_type >= ACPI_APMT_NODE_TYPE_COUNT) {
321 		dev_err(dev, "unsupported PMU type-%u\n", pmu_type);
322 		return NULL;
323 	}
324 
325 	if (pmu_type == ACPI_APMT_NODE_TYPE_ACPI) {
326 		memcpy(acpi_hid_string,
327 			&apmt_node->inst_primary,
328 			sizeof(apmt_node->inst_primary));
329 		name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%s_%u", PMUNAME,
330 				      arm_cspmu_type_str[pmu_type],
331 				      acpi_hid_string,
332 				      apmt_node->inst_secondary);
333 	} else {
334 		name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%d", PMUNAME,
335 				      arm_cspmu_type_str[pmu_type],
336 				      atomic_fetch_inc(&pmu_idx[pmu_type]));
337 	}
338 
339 	return name;
340 }
341 
342 static ssize_t arm_cspmu_cpumask_show(struct device *dev,
343 				      struct device_attribute *attr,
344 				      char *buf)
345 {
346 	struct pmu *pmu = dev_get_drvdata(dev);
347 	struct arm_cspmu *cspmu = to_arm_cspmu(pmu);
348 	struct dev_ext_attribute *eattr =
349 		container_of(attr, struct dev_ext_attribute, attr);
350 	unsigned long mask_id = (unsigned long)eattr->var;
351 	const cpumask_t *cpumask;
352 
353 	switch (mask_id) {
354 	case ARM_CSPMU_ACTIVE_CPU_MASK:
355 		cpumask = &cspmu->active_cpu;
356 		break;
357 	case ARM_CSPMU_ASSOCIATED_CPU_MASK:
358 		cpumask = &cspmu->associated_cpus;
359 		break;
360 	default:
361 		return 0;
362 	}
363 	return cpumap_print_to_pagebuf(true, buf, cpumask);
364 }
365 
366 static struct attribute *arm_cspmu_cpumask_attrs[] = {
367 	ARM_CSPMU_CPUMASK_ATTR(cpumask, ARM_CSPMU_ACTIVE_CPU_MASK),
368 	ARM_CSPMU_CPUMASK_ATTR(associated_cpus, ARM_CSPMU_ASSOCIATED_CPU_MASK),
369 	NULL,
370 };
371 
372 static struct attribute_group arm_cspmu_cpumask_attr_group = {
373 	.attrs = arm_cspmu_cpumask_attrs,
374 };
375 
376 struct impl_match {
377 	u32 pmiidr;
378 	u32 mask;
379 	int (*impl_init_ops)(struct arm_cspmu *cspmu);
380 };
381 
382 static const struct impl_match impl_match[] = {
383 	{
384 	  .pmiidr = ARM_CSPMU_IMPL_ID_NVIDIA,
385 	  .mask = ARM_CSPMU_PMIIDR_IMPLEMENTER,
386 	  .impl_init_ops = nv_cspmu_init_ops
387 	},
388 	{}
389 };
390 
391 static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
392 {
393 	int ret;
394 	struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
395 	struct acpi_apmt_node *apmt_node = arm_cspmu_apmt_node(cspmu->dev);
396 	const struct impl_match *match = impl_match;
397 
398 	/*
399 	 * Get PMU implementer and product id from APMT node.
400 	 * If APMT node doesn't have implementer/product id, try get it
401 	 * from PMIIDR.
402 	 */
403 	cspmu->impl.pmiidr =
404 		(apmt_node->impl_id) ? apmt_node->impl_id :
405 				       readl(cspmu->base0 + PMIIDR);
406 
407 	/* Find implementer specific attribute ops. */
408 	for (; match->pmiidr; match++) {
409 		const u32 mask = match->mask;
410 
411 		if ((match->pmiidr & mask) == (cspmu->impl.pmiidr & mask)) {
412 			ret = match->impl_init_ops(cspmu);
413 			if (ret)
414 				return ret;
415 
416 			break;
417 		}
418 	}
419 
420 	/* Use default callbacks if implementer doesn't provide one. */
421 	CHECK_DEFAULT_IMPL_OPS(impl_ops, get_event_attrs);
422 	CHECK_DEFAULT_IMPL_OPS(impl_ops, get_format_attrs);
423 	CHECK_DEFAULT_IMPL_OPS(impl_ops, get_identifier);
424 	CHECK_DEFAULT_IMPL_OPS(impl_ops, get_name);
425 	CHECK_DEFAULT_IMPL_OPS(impl_ops, is_cycle_counter_event);
426 	CHECK_DEFAULT_IMPL_OPS(impl_ops, event_type);
427 	CHECK_DEFAULT_IMPL_OPS(impl_ops, event_filter);
428 	CHECK_DEFAULT_IMPL_OPS(impl_ops, event_attr_is_visible);
429 
430 	return 0;
431 }
432 
433 static struct attribute_group *
434 arm_cspmu_alloc_event_attr_group(struct arm_cspmu *cspmu)
435 {
436 	struct attribute_group *event_group;
437 	struct device *dev = cspmu->dev;
438 	const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
439 
440 	event_group =
441 		devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);
442 	if (!event_group)
443 		return NULL;
444 
445 	event_group->name = "events";
446 	event_group->is_visible = impl_ops->event_attr_is_visible;
447 	event_group->attrs = impl_ops->get_event_attrs(cspmu);
448 
449 	if (!event_group->attrs)
450 		return NULL;
451 
452 	return event_group;
453 }
454 
455 static struct attribute_group *
456 arm_cspmu_alloc_format_attr_group(struct arm_cspmu *cspmu)
457 {
458 	struct attribute_group *format_group;
459 	struct device *dev = cspmu->dev;
460 
461 	format_group =
462 		devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);
463 	if (!format_group)
464 		return NULL;
465 
466 	format_group->name = "format";
467 	format_group->attrs = cspmu->impl.ops.get_format_attrs(cspmu);
468 
469 	if (!format_group->attrs)
470 		return NULL;
471 
472 	return format_group;
473 }
474 
475 static struct attribute_group **
476 arm_cspmu_alloc_attr_group(struct arm_cspmu *cspmu)
477 {
478 	struct attribute_group **attr_groups = NULL;
479 	struct device *dev = cspmu->dev;
480 	const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
481 	int ret;
482 
483 	ret = arm_cspmu_init_impl_ops(cspmu);
484 	if (ret)
485 		return NULL;
486 
487 	cspmu->identifier = impl_ops->get_identifier(cspmu);
488 	cspmu->name = impl_ops->get_name(cspmu);
489 
490 	if (!cspmu->identifier || !cspmu->name)
491 		return NULL;
492 
493 	attr_groups = devm_kcalloc(dev, 5, sizeof(struct attribute_group *),
494 				   GFP_KERNEL);
495 	if (!attr_groups)
496 		return NULL;
497 
498 	attr_groups[0] = arm_cspmu_alloc_event_attr_group(cspmu);
499 	attr_groups[1] = arm_cspmu_alloc_format_attr_group(cspmu);
500 	attr_groups[2] = &arm_cspmu_identifier_attr_group;
501 	attr_groups[3] = &arm_cspmu_cpumask_attr_group;
502 
503 	if (!attr_groups[0] || !attr_groups[1])
504 		return NULL;
505 
506 	return attr_groups;
507 }
508 
509 static inline void arm_cspmu_reset_counters(struct arm_cspmu *cspmu)
510 {
511 	u32 pmcr = 0;
512 
513 	pmcr |= PMCR_P;
514 	pmcr |= PMCR_C;
515 	writel(pmcr, cspmu->base0 + PMCR);
516 }
517 
518 static inline void arm_cspmu_start_counters(struct arm_cspmu *cspmu)
519 {
520 	writel(PMCR_E, cspmu->base0 + PMCR);
521 }
522 
523 static inline void arm_cspmu_stop_counters(struct arm_cspmu *cspmu)
524 {
525 	writel(0, cspmu->base0 + PMCR);
526 }
527 
528 static void arm_cspmu_enable(struct pmu *pmu)
529 {
530 	bool disabled;
531 	struct arm_cspmu *cspmu = to_arm_cspmu(pmu);
532 
533 	disabled = bitmap_empty(cspmu->hw_events.used_ctrs,
534 				cspmu->num_logical_ctrs);
535 
536 	if (disabled)
537 		return;
538 
539 	arm_cspmu_start_counters(cspmu);
540 }
541 
542 static void arm_cspmu_disable(struct pmu *pmu)
543 {
544 	struct arm_cspmu *cspmu = to_arm_cspmu(pmu);
545 
546 	arm_cspmu_stop_counters(cspmu);
547 }
548 
549 static int arm_cspmu_get_event_idx(struct arm_cspmu_hw_events *hw_events,
550 				struct perf_event *event)
551 {
552 	int idx;
553 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
554 
555 	if (supports_cycle_counter(cspmu)) {
556 		if (cspmu->impl.ops.is_cycle_counter_event(event)) {
557 			/* Search for available cycle counter. */
558 			if (test_and_set_bit(cspmu->cycle_counter_logical_idx,
559 					     hw_events->used_ctrs))
560 				return -EAGAIN;
561 
562 			return cspmu->cycle_counter_logical_idx;
563 		}
564 
565 		/*
566 		 * Search a regular counter from the used counter bitmap.
567 		 * The cycle counter divides the bitmap into two parts. Search
568 		 * the first then second half to exclude the cycle counter bit.
569 		 */
570 		idx = find_first_zero_bit(hw_events->used_ctrs,
571 					  cspmu->cycle_counter_logical_idx);
572 		if (idx >= cspmu->cycle_counter_logical_idx) {
573 			idx = find_next_zero_bit(
574 				hw_events->used_ctrs,
575 				cspmu->num_logical_ctrs,
576 				cspmu->cycle_counter_logical_idx + 1);
577 		}
578 	} else {
579 		idx = find_first_zero_bit(hw_events->used_ctrs,
580 					  cspmu->num_logical_ctrs);
581 	}
582 
583 	if (idx >= cspmu->num_logical_ctrs)
584 		return -EAGAIN;
585 
586 	set_bit(idx, hw_events->used_ctrs);
587 
588 	return idx;
589 }
590 
591 static bool arm_cspmu_validate_event(struct pmu *pmu,
592 				 struct arm_cspmu_hw_events *hw_events,
593 				 struct perf_event *event)
594 {
595 	if (is_software_event(event))
596 		return true;
597 
598 	/* Reject groups spanning multiple HW PMUs. */
599 	if (event->pmu != pmu)
600 		return false;
601 
602 	return (arm_cspmu_get_event_idx(hw_events, event) >= 0);
603 }
604 
605 /*
606  * Make sure the group of events can be scheduled at once
607  * on the PMU.
608  */
609 static bool arm_cspmu_validate_group(struct perf_event *event)
610 {
611 	struct perf_event *sibling, *leader = event->group_leader;
612 	struct arm_cspmu_hw_events fake_hw_events;
613 
614 	if (event->group_leader == event)
615 		return true;
616 
617 	memset(&fake_hw_events, 0, sizeof(fake_hw_events));
618 
619 	if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events, leader))
620 		return false;
621 
622 	for_each_sibling_event(sibling, leader) {
623 		if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events,
624 						  sibling))
625 			return false;
626 	}
627 
628 	return arm_cspmu_validate_event(event->pmu, &fake_hw_events, event);
629 }
630 
631 static int arm_cspmu_event_init(struct perf_event *event)
632 {
633 	struct arm_cspmu *cspmu;
634 	struct hw_perf_event *hwc = &event->hw;
635 
636 	cspmu = to_arm_cspmu(event->pmu);
637 
638 	/*
639 	 * Following other "uncore" PMUs, we do not support sampling mode or
640 	 * attach to a task (per-process mode).
641 	 */
642 	if (is_sampling_event(event)) {
643 		dev_dbg(cspmu->pmu.dev,
644 			"Can't support sampling events\n");
645 		return -EOPNOTSUPP;
646 	}
647 
648 	if (event->cpu < 0 || event->attach_state & PERF_ATTACH_TASK) {
649 		dev_dbg(cspmu->pmu.dev,
650 			"Can't support per-task counters\n");
651 		return -EINVAL;
652 	}
653 
654 	/*
655 	 * Make sure the CPU assignment is on one of the CPUs associated with
656 	 * this PMU.
657 	 */
658 	if (!cpumask_test_cpu(event->cpu, &cspmu->associated_cpus)) {
659 		dev_dbg(cspmu->pmu.dev,
660 			"Requested cpu is not associated with the PMU\n");
661 		return -EINVAL;
662 	}
663 
664 	/* Enforce the current active CPU to handle the events in this PMU. */
665 	event->cpu = cpumask_first(&cspmu->active_cpu);
666 	if (event->cpu >= nr_cpu_ids)
667 		return -EINVAL;
668 
669 	if (!arm_cspmu_validate_group(event))
670 		return -EINVAL;
671 
672 	/*
673 	 * The logical counter id is tracked with hw_perf_event.extra_reg.idx.
674 	 * The physical counter id is tracked with hw_perf_event.idx.
675 	 * We don't assign an index until we actually place the event onto
676 	 * hardware. Use -1 to signify that we haven't decided where to put it
677 	 * yet.
678 	 */
679 	hwc->idx = -1;
680 	hwc->extra_reg.idx = -1;
681 	hwc->config = cspmu->impl.ops.event_type(event);
682 
683 	return 0;
684 }
685 
686 static inline u32 counter_offset(u32 reg_sz, u32 ctr_idx)
687 {
688 	return (PMEVCNTR_LO + (reg_sz * ctr_idx));
689 }
690 
691 static void arm_cspmu_write_counter(struct perf_event *event, u64 val)
692 {
693 	u32 offset;
694 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
695 
696 	if (use_64b_counter_reg(cspmu)) {
697 		offset = counter_offset(sizeof(u64), event->hw.idx);
698 
699 		writeq(val, cspmu->base1 + offset);
700 	} else {
701 		offset = counter_offset(sizeof(u32), event->hw.idx);
702 
703 		writel(lower_32_bits(val), cspmu->base1 + offset);
704 	}
705 }
706 
707 static u64 arm_cspmu_read_counter(struct perf_event *event)
708 {
709 	u32 offset;
710 	const void __iomem *counter_addr;
711 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
712 
713 	if (use_64b_counter_reg(cspmu)) {
714 		offset = counter_offset(sizeof(u64), event->hw.idx);
715 		counter_addr = cspmu->base1 + offset;
716 
717 		return cspmu->has_atomic_dword ?
718 			       readq(counter_addr) :
719 			       read_reg64_hilohi(counter_addr, HILOHI_MAX_POLL);
720 	}
721 
722 	offset = counter_offset(sizeof(u32), event->hw.idx);
723 	return readl(cspmu->base1 + offset);
724 }
725 
726 /*
727  * arm_cspmu_set_event_period: Set the period for the counter.
728  *
729  * To handle cases of extreme interrupt latency, we program
730  * the counter with half of the max count for the counters.
731  */
732 static void arm_cspmu_set_event_period(struct perf_event *event)
733 {
734 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
735 	u64 val = counter_mask(cspmu) >> 1ULL;
736 
737 	local64_set(&event->hw.prev_count, val);
738 	arm_cspmu_write_counter(event, val);
739 }
740 
741 static void arm_cspmu_enable_counter(struct arm_cspmu *cspmu, int idx)
742 {
743 	u32 reg_id, reg_bit, inten_off, cnten_off;
744 
745 	reg_id = COUNTER_TO_SET_CLR_ID(idx);
746 	reg_bit = COUNTER_TO_SET_CLR_BIT(idx);
747 
748 	inten_off = PMINTENSET + (4 * reg_id);
749 	cnten_off = PMCNTENSET + (4 * reg_id);
750 
751 	writel(BIT(reg_bit), cspmu->base0 + inten_off);
752 	writel(BIT(reg_bit), cspmu->base0 + cnten_off);
753 }
754 
755 static void arm_cspmu_disable_counter(struct arm_cspmu *cspmu, int idx)
756 {
757 	u32 reg_id, reg_bit, inten_off, cnten_off;
758 
759 	reg_id = COUNTER_TO_SET_CLR_ID(idx);
760 	reg_bit = COUNTER_TO_SET_CLR_BIT(idx);
761 
762 	inten_off = PMINTENCLR + (4 * reg_id);
763 	cnten_off = PMCNTENCLR + (4 * reg_id);
764 
765 	writel(BIT(reg_bit), cspmu->base0 + cnten_off);
766 	writel(BIT(reg_bit), cspmu->base0 + inten_off);
767 }
768 
769 static void arm_cspmu_event_update(struct perf_event *event)
770 {
771 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
772 	struct hw_perf_event *hwc = &event->hw;
773 	u64 delta, prev, now;
774 
775 	do {
776 		prev = local64_read(&hwc->prev_count);
777 		now = arm_cspmu_read_counter(event);
778 	} while (local64_cmpxchg(&hwc->prev_count, prev, now) != prev);
779 
780 	delta = (now - prev) & counter_mask(cspmu);
781 	local64_add(delta, &event->count);
782 }
783 
784 static inline void arm_cspmu_set_event(struct arm_cspmu *cspmu,
785 					struct hw_perf_event *hwc)
786 {
787 	u32 offset = PMEVTYPER + (4 * hwc->idx);
788 
789 	writel(hwc->config, cspmu->base0 + offset);
790 }
791 
792 static inline void arm_cspmu_set_ev_filter(struct arm_cspmu *cspmu,
793 					   struct hw_perf_event *hwc,
794 					   u32 filter)
795 {
796 	u32 offset = PMEVFILTR + (4 * hwc->idx);
797 
798 	writel(filter, cspmu->base0 + offset);
799 }
800 
801 static inline void arm_cspmu_set_cc_filter(struct arm_cspmu *cspmu, u32 filter)
802 {
803 	u32 offset = PMCCFILTR;
804 
805 	writel(filter, cspmu->base0 + offset);
806 }
807 
808 static void arm_cspmu_start(struct perf_event *event, int pmu_flags)
809 {
810 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
811 	struct hw_perf_event *hwc = &event->hw;
812 	u32 filter;
813 
814 	/* We always reprogram the counter */
815 	if (pmu_flags & PERF_EF_RELOAD)
816 		WARN_ON(!(hwc->state & PERF_HES_UPTODATE));
817 
818 	arm_cspmu_set_event_period(event);
819 
820 	filter = cspmu->impl.ops.event_filter(event);
821 
822 	if (event->hw.extra_reg.idx == cspmu->cycle_counter_logical_idx) {
823 		arm_cspmu_set_cc_filter(cspmu, filter);
824 	} else {
825 		arm_cspmu_set_event(cspmu, hwc);
826 		arm_cspmu_set_ev_filter(cspmu, hwc, filter);
827 	}
828 
829 	hwc->state = 0;
830 
831 	arm_cspmu_enable_counter(cspmu, hwc->idx);
832 }
833 
834 static void arm_cspmu_stop(struct perf_event *event, int pmu_flags)
835 {
836 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
837 	struct hw_perf_event *hwc = &event->hw;
838 
839 	if (hwc->state & PERF_HES_STOPPED)
840 		return;
841 
842 	arm_cspmu_disable_counter(cspmu, hwc->idx);
843 	arm_cspmu_event_update(event);
844 
845 	hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
846 }
847 
848 static inline u32 to_phys_idx(struct arm_cspmu *cspmu, u32 idx)
849 {
850 	return (idx == cspmu->cycle_counter_logical_idx) ?
851 		ARM_CSPMU_CYCLE_CNTR_IDX : idx;
852 }
853 
854 static int arm_cspmu_add(struct perf_event *event, int flags)
855 {
856 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
857 	struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;
858 	struct hw_perf_event *hwc = &event->hw;
859 	int idx;
860 
861 	if (WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(),
862 					   &cspmu->associated_cpus)))
863 		return -ENOENT;
864 
865 	idx = arm_cspmu_get_event_idx(hw_events, event);
866 	if (idx < 0)
867 		return idx;
868 
869 	hw_events->events[idx] = event;
870 	hwc->idx = to_phys_idx(cspmu, idx);
871 	hwc->extra_reg.idx = idx;
872 	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
873 
874 	if (flags & PERF_EF_START)
875 		arm_cspmu_start(event, PERF_EF_RELOAD);
876 
877 	/* Propagate changes to the userspace mapping. */
878 	perf_event_update_userpage(event);
879 
880 	return 0;
881 }
882 
883 static void arm_cspmu_del(struct perf_event *event, int flags)
884 {
885 	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
886 	struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;
887 	struct hw_perf_event *hwc = &event->hw;
888 	int idx = hwc->extra_reg.idx;
889 
890 	arm_cspmu_stop(event, PERF_EF_UPDATE);
891 
892 	hw_events->events[idx] = NULL;
893 
894 	clear_bit(idx, hw_events->used_ctrs);
895 
896 	perf_event_update_userpage(event);
897 }
898 
899 static void arm_cspmu_read(struct perf_event *event)
900 {
901 	arm_cspmu_event_update(event);
902 }
903 
904 static struct arm_cspmu *arm_cspmu_alloc(struct platform_device *pdev)
905 {
906 	struct acpi_apmt_node *apmt_node;
907 	struct arm_cspmu *cspmu;
908 	struct device *dev = &pdev->dev;
909 
910 	cspmu = devm_kzalloc(dev, sizeof(*cspmu), GFP_KERNEL);
911 	if (!cspmu)
912 		return NULL;
913 
914 	cspmu->dev = dev;
915 	platform_set_drvdata(pdev, cspmu);
916 
917 	apmt_node = arm_cspmu_apmt_node(dev);
918 	cspmu->has_atomic_dword = apmt_node->flags & ACPI_APMT_FLAGS_ATOMIC;
919 
920 	return cspmu;
921 }
922 
923 static int arm_cspmu_init_mmio(struct arm_cspmu *cspmu)
924 {
925 	struct device *dev;
926 	struct platform_device *pdev;
927 
928 	dev = cspmu->dev;
929 	pdev = to_platform_device(dev);
930 
931 	/* Base address for page 0. */
932 	cspmu->base0 = devm_platform_ioremap_resource(pdev, 0);
933 	if (IS_ERR(cspmu->base0)) {
934 		dev_err(dev, "ioremap failed for page-0 resource\n");
935 		return PTR_ERR(cspmu->base0);
936 	}
937 
938 	/* Base address for page 1 if supported. Otherwise point to page 0. */
939 	cspmu->base1 = cspmu->base0;
940 	if (platform_get_resource(pdev, IORESOURCE_MEM, 1)) {
941 		cspmu->base1 = devm_platform_ioremap_resource(pdev, 1);
942 		if (IS_ERR(cspmu->base1)) {
943 			dev_err(dev, "ioremap failed for page-1 resource\n");
944 			return PTR_ERR(cspmu->base1);
945 		}
946 	}
947 
948 	cspmu->pmcfgr = readl(cspmu->base0 + PMCFGR);
949 
950 	cspmu->num_logical_ctrs = FIELD_GET(PMCFGR_N, cspmu->pmcfgr) + 1;
951 
952 	cspmu->cycle_counter_logical_idx = ARM_CSPMU_MAX_HW_CNTRS;
953 
954 	if (supports_cycle_counter(cspmu)) {
955 		/*
956 		 * The last logical counter is mapped to cycle counter if
957 		 * there is a gap between regular and cycle counter. Otherwise,
958 		 * logical and physical have 1-to-1 mapping.
959 		 */
960 		cspmu->cycle_counter_logical_idx =
961 			(cspmu->num_logical_ctrs <= ARM_CSPMU_CYCLE_CNTR_IDX) ?
962 				cspmu->num_logical_ctrs - 1 :
963 				ARM_CSPMU_CYCLE_CNTR_IDX;
964 	}
965 
966 	cspmu->num_set_clr_reg =
967 		DIV_ROUND_UP(cspmu->num_logical_ctrs,
968 				ARM_CSPMU_SET_CLR_COUNTER_NUM);
969 
970 	cspmu->hw_events.events =
971 		devm_kcalloc(dev, cspmu->num_logical_ctrs,
972 			     sizeof(*cspmu->hw_events.events), GFP_KERNEL);
973 
974 	if (!cspmu->hw_events.events)
975 		return -ENOMEM;
976 
977 	return 0;
978 }
979 
980 static inline int arm_cspmu_get_reset_overflow(struct arm_cspmu *cspmu,
981 					       u32 *pmovs)
982 {
983 	int i;
984 	u32 pmovclr_offset = PMOVSCLR;
985 	u32 has_overflowed = 0;
986 
987 	for (i = 0; i < cspmu->num_set_clr_reg; ++i) {
988 		pmovs[i] = readl(cspmu->base1 + pmovclr_offset);
989 		has_overflowed |= pmovs[i];
990 		writel(pmovs[i], cspmu->base1 + pmovclr_offset);
991 		pmovclr_offset += sizeof(u32);
992 	}
993 
994 	return has_overflowed != 0;
995 }
996 
997 static irqreturn_t arm_cspmu_handle_irq(int irq_num, void *dev)
998 {
999 	int idx, has_overflowed;
1000 	struct perf_event *event;
1001 	struct arm_cspmu *cspmu = dev;
1002 	DECLARE_BITMAP(pmovs, ARM_CSPMU_MAX_HW_CNTRS);
1003 	bool handled = false;
1004 
1005 	arm_cspmu_stop_counters(cspmu);
1006 
1007 	has_overflowed = arm_cspmu_get_reset_overflow(cspmu, (u32 *)pmovs);
1008 	if (!has_overflowed)
1009 		goto done;
1010 
1011 	for_each_set_bit(idx, cspmu->hw_events.used_ctrs,
1012 			cspmu->num_logical_ctrs) {
1013 		event = cspmu->hw_events.events[idx];
1014 
1015 		if (!event)
1016 			continue;
1017 
1018 		if (!test_bit(event->hw.idx, pmovs))
1019 			continue;
1020 
1021 		arm_cspmu_event_update(event);
1022 		arm_cspmu_set_event_period(event);
1023 
1024 		handled = true;
1025 	}
1026 
1027 done:
1028 	arm_cspmu_start_counters(cspmu);
1029 	return IRQ_RETVAL(handled);
1030 }
1031 
1032 static int arm_cspmu_request_irq(struct arm_cspmu *cspmu)
1033 {
1034 	int irq, ret;
1035 	struct device *dev;
1036 	struct platform_device *pdev;
1037 
1038 	dev = cspmu->dev;
1039 	pdev = to_platform_device(dev);
1040 
1041 	/* Skip IRQ request if the PMU does not support overflow interrupt. */
1042 	irq = platform_get_irq_optional(pdev, 0);
1043 	if (irq < 0)
1044 		return irq == -ENXIO ? 0 : irq;
1045 
1046 	ret = devm_request_irq(dev, irq, arm_cspmu_handle_irq,
1047 			       IRQF_NOBALANCING | IRQF_NO_THREAD, dev_name(dev),
1048 			       cspmu);
1049 	if (ret) {
1050 		dev_err(dev, "Could not request IRQ %d\n", irq);
1051 		return ret;
1052 	}
1053 
1054 	cspmu->irq = irq;
1055 
1056 	return 0;
1057 }
1058 
1059 #if defined(CONFIG_ACPI) && defined(CONFIG_ARM64)
1060 #include <acpi/processor.h>
1061 
1062 static inline int arm_cspmu_find_cpu_container(int cpu, u32 container_uid)
1063 {
1064 	u32 acpi_uid;
1065 	struct device *cpu_dev;
1066 	struct acpi_device *acpi_dev;
1067 
1068 	cpu_dev = get_cpu_device(cpu);
1069 	if (!cpu_dev)
1070 		return -ENODEV;
1071 
1072 	acpi_dev = ACPI_COMPANION(cpu_dev);
1073 	while (acpi_dev) {
1074 		if (!strcmp(acpi_device_hid(acpi_dev),
1075 			    ACPI_PROCESSOR_CONTAINER_HID) &&
1076 		    !kstrtouint(acpi_device_uid(acpi_dev), 0, &acpi_uid) &&
1077 		    acpi_uid == container_uid)
1078 			return 0;
1079 
1080 		acpi_dev = acpi_dev_parent(acpi_dev);
1081 	}
1082 
1083 	return -ENODEV;
1084 }
1085 
1086 static int arm_cspmu_acpi_get_cpus(struct arm_cspmu *cspmu)
1087 {
1088 	struct acpi_apmt_node *apmt_node;
1089 	int affinity_flag;
1090 	int cpu;
1091 
1092 	apmt_node = arm_cspmu_apmt_node(cspmu->dev);
1093 	affinity_flag = apmt_node->flags & ACPI_APMT_FLAGS_AFFINITY;
1094 
1095 	if (affinity_flag == ACPI_APMT_FLAGS_AFFINITY_PROC) {
1096 		for_each_possible_cpu(cpu) {
1097 			if (apmt_node->proc_affinity ==
1098 			    get_acpi_id_for_cpu(cpu)) {
1099 				cpumask_set_cpu(cpu, &cspmu->associated_cpus);
1100 				break;
1101 			}
1102 		}
1103 	} else {
1104 		for_each_possible_cpu(cpu) {
1105 			if (arm_cspmu_find_cpu_container(
1106 				    cpu, apmt_node->proc_affinity))
1107 				continue;
1108 
1109 			cpumask_set_cpu(cpu, &cspmu->associated_cpus);
1110 		}
1111 	}
1112 
1113 	if (cpumask_empty(&cspmu->associated_cpus)) {
1114 		dev_dbg(cspmu->dev, "No cpu associated with the PMU\n");
1115 		return -ENODEV;
1116 	}
1117 
1118 	return 0;
1119 }
1120 #else
1121 static int arm_cspmu_acpi_get_cpus(struct arm_cspmu *cspmu)
1122 {
1123 	return -ENODEV;
1124 }
1125 #endif
1126 
1127 static int arm_cspmu_get_cpus(struct arm_cspmu *cspmu)
1128 {
1129 	return arm_cspmu_acpi_get_cpus(cspmu);
1130 }
1131 
1132 static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)
1133 {
1134 	int ret, capabilities;
1135 	struct attribute_group **attr_groups;
1136 
1137 	attr_groups = arm_cspmu_alloc_attr_group(cspmu);
1138 	if (!attr_groups)
1139 		return -ENOMEM;
1140 
1141 	ret = cpuhp_state_add_instance(arm_cspmu_cpuhp_state,
1142 				       &cspmu->cpuhp_node);
1143 	if (ret)
1144 		return ret;
1145 
1146 	capabilities = PERF_PMU_CAP_NO_EXCLUDE;
1147 	if (cspmu->irq == 0)
1148 		capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
1149 
1150 	cspmu->pmu = (struct pmu){
1151 		.task_ctx_nr	= perf_invalid_context,
1152 		.module		= THIS_MODULE,
1153 		.pmu_enable	= arm_cspmu_enable,
1154 		.pmu_disable	= arm_cspmu_disable,
1155 		.event_init	= arm_cspmu_event_init,
1156 		.add		= arm_cspmu_add,
1157 		.del		= arm_cspmu_del,
1158 		.start		= arm_cspmu_start,
1159 		.stop		= arm_cspmu_stop,
1160 		.read		= arm_cspmu_read,
1161 		.attr_groups	= (const struct attribute_group **)attr_groups,
1162 		.capabilities	= capabilities,
1163 	};
1164 
1165 	/* Hardware counter init */
1166 	arm_cspmu_stop_counters(cspmu);
1167 	arm_cspmu_reset_counters(cspmu);
1168 
1169 	ret = perf_pmu_register(&cspmu->pmu, cspmu->name, -1);
1170 	if (ret) {
1171 		cpuhp_state_remove_instance(arm_cspmu_cpuhp_state,
1172 					    &cspmu->cpuhp_node);
1173 	}
1174 
1175 	return ret;
1176 }
1177 
1178 static int arm_cspmu_device_probe(struct platform_device *pdev)
1179 {
1180 	int ret;
1181 	struct arm_cspmu *cspmu;
1182 
1183 	cspmu = arm_cspmu_alloc(pdev);
1184 	if (!cspmu)
1185 		return -ENOMEM;
1186 
1187 	ret = arm_cspmu_init_mmio(cspmu);
1188 	if (ret)
1189 		return ret;
1190 
1191 	ret = arm_cspmu_request_irq(cspmu);
1192 	if (ret)
1193 		return ret;
1194 
1195 	ret = arm_cspmu_get_cpus(cspmu);
1196 	if (ret)
1197 		return ret;
1198 
1199 	ret = arm_cspmu_register_pmu(cspmu);
1200 	if (ret)
1201 		return ret;
1202 
1203 	return 0;
1204 }
1205 
1206 static int arm_cspmu_device_remove(struct platform_device *pdev)
1207 {
1208 	struct arm_cspmu *cspmu = platform_get_drvdata(pdev);
1209 
1210 	perf_pmu_unregister(&cspmu->pmu);
1211 	cpuhp_state_remove_instance(arm_cspmu_cpuhp_state, &cspmu->cpuhp_node);
1212 
1213 	return 0;
1214 }
1215 
1216 static const struct platform_device_id arm_cspmu_id[] = {
1217 	{DRVNAME, 0},
1218 	{ },
1219 };
1220 MODULE_DEVICE_TABLE(platform, arm_cspmu_id);
1221 
1222 static struct platform_driver arm_cspmu_driver = {
1223 	.driver = {
1224 			.name = DRVNAME,
1225 			.suppress_bind_attrs = true,
1226 		},
1227 	.probe = arm_cspmu_device_probe,
1228 	.remove = arm_cspmu_device_remove,
1229 	.id_table = arm_cspmu_id,
1230 };
1231 
1232 static void arm_cspmu_set_active_cpu(int cpu, struct arm_cspmu *cspmu)
1233 {
1234 	cpumask_set_cpu(cpu, &cspmu->active_cpu);
1235 	if (cspmu->irq)
1236 		WARN_ON(irq_set_affinity(cspmu->irq, &cspmu->active_cpu));
1237 }
1238 
1239 static int arm_cspmu_cpu_online(unsigned int cpu, struct hlist_node *node)
1240 {
1241 	struct arm_cspmu *cspmu =
1242 		hlist_entry_safe(node, struct arm_cspmu, cpuhp_node);
1243 
1244 	if (!cpumask_test_cpu(cpu, &cspmu->associated_cpus))
1245 		return 0;
1246 
1247 	/* If the PMU is already managed, there is nothing to do */
1248 	if (!cpumask_empty(&cspmu->active_cpu))
1249 		return 0;
1250 
1251 	/* Use this CPU for event counting */
1252 	arm_cspmu_set_active_cpu(cpu, cspmu);
1253 
1254 	return 0;
1255 }
1256 
1257 static int arm_cspmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
1258 {
1259 	int dst;
1260 	struct cpumask online_supported;
1261 
1262 	struct arm_cspmu *cspmu =
1263 		hlist_entry_safe(node, struct arm_cspmu, cpuhp_node);
1264 
1265 	/* Nothing to do if this CPU doesn't own the PMU */
1266 	if (!cpumask_test_and_clear_cpu(cpu, &cspmu->active_cpu))
1267 		return 0;
1268 
1269 	/* Choose a new CPU to migrate ownership of the PMU to */
1270 	cpumask_and(&online_supported, &cspmu->associated_cpus,
1271 		    cpu_online_mask);
1272 	dst = cpumask_any_but(&online_supported, cpu);
1273 	if (dst >= nr_cpu_ids)
1274 		return 0;
1275 
1276 	/* Use this CPU for event counting */
1277 	perf_pmu_migrate_context(&cspmu->pmu, cpu, dst);
1278 	arm_cspmu_set_active_cpu(dst, cspmu);
1279 
1280 	return 0;
1281 }
1282 
1283 static int __init arm_cspmu_init(void)
1284 {
1285 	int ret;
1286 
1287 	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
1288 					"perf/arm/cspmu:online",
1289 					arm_cspmu_cpu_online,
1290 					arm_cspmu_cpu_teardown);
1291 	if (ret < 0)
1292 		return ret;
1293 	arm_cspmu_cpuhp_state = ret;
1294 	return platform_driver_register(&arm_cspmu_driver);
1295 }
1296 
1297 static void __exit arm_cspmu_exit(void)
1298 {
1299 	platform_driver_unregister(&arm_cspmu_driver);
1300 	cpuhp_remove_multi_state(arm_cspmu_cpuhp_state);
1301 }
1302 
1303 module_init(arm_cspmu_init);
1304 module_exit(arm_cspmu_exit);
1305 
1306 MODULE_LICENSE("GPL v2");
1307