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v5.9
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * ACPI probing code for ARM performance counters.
  4 *
  5 * Copyright (C) 2017 ARM Ltd.
  6 */
  7
  8#include <linux/acpi.h>
  9#include <linux/cpumask.h>
 10#include <linux/init.h>
 11#include <linux/irq.h>
 12#include <linux/irqdesc.h>
 13#include <linux/percpu.h>
 14#include <linux/perf/arm_pmu.h>
 15
 
 16#include <asm/cputype.h>
 17
 18static DEFINE_PER_CPU(struct arm_pmu *, probed_pmus);
 19static DEFINE_PER_CPU(int, pmu_irqs);
 20
 21static int arm_pmu_acpi_register_irq(int cpu)
 22{
 23	struct acpi_madt_generic_interrupt *gicc;
 24	int gsi, trigger;
 25
 26	gicc = acpi_cpu_get_madt_gicc(cpu);
 27
 28	gsi = gicc->performance_interrupt;
 29
 30	/*
 31	 * Per the ACPI spec, the MADT cannot describe a PMU that doesn't
 32	 * have an interrupt. QEMU advertises this by using a GSI of zero,
 33	 * which is not known to be valid on any hardware despite being
 34	 * valid per the spec. Take the pragmatic approach and reject a
 35	 * GSI of zero for now.
 36	 */
 37	if (!gsi)
 38		return 0;
 39
 40	if (gicc->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE)
 41		trigger = ACPI_EDGE_SENSITIVE;
 42	else
 43		trigger = ACPI_LEVEL_SENSITIVE;
 44
 45	/*
 46	 * Helpfully, the MADT GICC doesn't have a polarity flag for the
 47	 * "performance interrupt". Luckily, on compliant GICs the polarity is
 48	 * a fixed value in HW (for both SPIs and PPIs) that we cannot change
 49	 * from SW.
 50	 *
 51	 * Here we pass in ACPI_ACTIVE_HIGH to keep the core code happy. This
 52	 * may not match the real polarity, but that should not matter.
 53	 *
 54	 * Other interrupt controllers are not supported with ACPI.
 55	 */
 56	return acpi_register_gsi(NULL, gsi, trigger, ACPI_ACTIVE_HIGH);
 57}
 58
 59static void arm_pmu_acpi_unregister_irq(int cpu)
 60{
 61	struct acpi_madt_generic_interrupt *gicc;
 62	int gsi;
 63
 64	gicc = acpi_cpu_get_madt_gicc(cpu);
 65
 66	gsi = gicc->performance_interrupt;
 67	if (gsi)
 68		acpi_unregister_gsi(gsi);
 69}
 70
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 71#if IS_ENABLED(CONFIG_ARM_SPE_PMU)
 72static struct resource spe_resources[] = {
 73	{
 74		/* irq */
 75		.flags          = IORESOURCE_IRQ,
 76	}
 77};
 78
 79static struct platform_device spe_dev = {
 80	.name = ARMV8_SPE_PDEV_NAME,
 81	.id = -1,
 82	.resource = spe_resources,
 83	.num_resources = ARRAY_SIZE(spe_resources)
 84};
 85
 
 
 
 
 
 86/*
 87 * For lack of a better place, hook the normal PMU MADT walk
 88 * and create a SPE device if we detect a recent MADT with
 89 * a homogeneous PPI mapping.
 90 */
 91static void arm_spe_acpi_register_device(void)
 92{
 93	int cpu, hetid, irq, ret;
 94	bool first = true;
 95	u16 gsi = 0;
 96
 97	/*
 98	 * Sanity check all the GICC tables for the same interrupt number.
 99	 * For now, we only support homogeneous ACPI/SPE machines.
100	 */
101	for_each_possible_cpu(cpu) {
102		struct acpi_madt_generic_interrupt *gicc;
103
104		gicc = acpi_cpu_get_madt_gicc(cpu);
105		if (gicc->header.length < ACPI_MADT_GICC_SPE)
106			return;
107
108		if (first) {
109			gsi = gicc->spe_interrupt;
110			if (!gsi)
111				return;
112			hetid = find_acpi_cpu_topology_hetero_id(cpu);
113			first = false;
114		} else if ((gsi != gicc->spe_interrupt) ||
115			   (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {
116			pr_warn("ACPI: SPE must be homogeneous\n");
117			return;
118		}
119	}
 
120
121	irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE,
122				ACPI_ACTIVE_HIGH);
123	if (irq < 0) {
124		pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi);
125		return;
126	}
127
128	spe_resources[0].start = irq;
129	ret = platform_device_register(&spe_dev);
130	if (ret < 0) {
131		pr_warn("ACPI: SPE: Unable to register device\n");
132		acpi_unregister_gsi(gsi);
133	}
 
 
 
 
 
134}
135#else
136static inline void arm_spe_acpi_register_device(void)
137{
 
138}
139#endif /* CONFIG_ARM_SPE_PMU */
140
141static int arm_pmu_acpi_parse_irqs(void)
142{
143	int irq, cpu, irq_cpu, err;
144
145	for_each_possible_cpu(cpu) {
146		irq = arm_pmu_acpi_register_irq(cpu);
147		if (irq < 0) {
148			err = irq;
149			pr_warn("Unable to parse ACPI PMU IRQ for CPU%d: %d\n",
150				cpu, err);
151			goto out_err;
152		} else if (irq == 0) {
153			pr_warn("No ACPI PMU IRQ for CPU%d\n", cpu);
154		}
155
156		/*
157		 * Log and request the IRQ so the core arm_pmu code can manage
158		 * it. We'll have to sanity-check IRQs later when we associate
159		 * them with their PMUs.
160		 */
161		per_cpu(pmu_irqs, cpu) = irq;
162		armpmu_request_irq(irq, cpu);
 
 
163	}
164
165	return 0;
166
167out_err:
168	for_each_possible_cpu(cpu) {
169		irq = per_cpu(pmu_irqs, cpu);
170		if (!irq)
171			continue;
172
173		arm_pmu_acpi_unregister_irq(cpu);
174
175		/*
176		 * Blat all copies of the IRQ so that we only unregister the
177		 * corresponding GSI once (e.g. when we have PPIs).
178		 */
179		for_each_possible_cpu(irq_cpu) {
180			if (per_cpu(pmu_irqs, irq_cpu) == irq)
181				per_cpu(pmu_irqs, irq_cpu) = 0;
182		}
183	}
184
185	return err;
186}
187
188static struct arm_pmu *arm_pmu_acpi_find_alloc_pmu(void)
189{
190	unsigned long cpuid = read_cpuid_id();
191	struct arm_pmu *pmu;
192	int cpu;
193
194	for_each_possible_cpu(cpu) {
195		pmu = per_cpu(probed_pmus, cpu);
196		if (!pmu || pmu->acpi_cpuid != cpuid)
197			continue;
198
199		return pmu;
200	}
201
202	pmu = armpmu_alloc_atomic();
203	if (!pmu) {
204		pr_warn("Unable to allocate PMU for CPU%d\n",
205			smp_processor_id());
206		return NULL;
207	}
208
209	pmu->acpi_cpuid = cpuid;
210
211	return pmu;
212}
213
214/*
215 * Check whether the new IRQ is compatible with those already associated with
216 * the PMU (e.g. we don't have mismatched PPIs).
217 */
218static bool pmu_irq_matches(struct arm_pmu *pmu, int irq)
219{
220	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
221	int cpu;
222
223	if (!irq)
224		return true;
225
226	for_each_cpu(cpu, &pmu->supported_cpus) {
227		int other_irq = per_cpu(hw_events->irq, cpu);
228		if (!other_irq)
229			continue;
230
231		if (irq == other_irq)
232			continue;
233		if (!irq_is_percpu_devid(irq) && !irq_is_percpu_devid(other_irq))
234			continue;
235
236		pr_warn("mismatched PPIs detected\n");
237		return false;
238	}
239
240	return true;
241}
242
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
243/*
244 * This must run before the common arm_pmu hotplug logic, so that we can
245 * associate a CPU and its interrupt before the common code tries to manage the
246 * affinity and so on.
247 *
248 * Note that hotplug events are serialized, so we cannot race with another CPU
249 * coming up. The perf core won't open events while a hotplug event is in
250 * progress.
251 */
252static int arm_pmu_acpi_cpu_starting(unsigned int cpu)
253{
254	struct arm_pmu *pmu;
255	struct pmu_hw_events __percpu *hw_events;
256	int irq;
257
258	/* If we've already probed this CPU, we have nothing to do */
259	if (per_cpu(probed_pmus, cpu))
260		return 0;
261
262	irq = per_cpu(pmu_irqs, cpu);
 
 
 
 
 
263
264	pmu = arm_pmu_acpi_find_alloc_pmu();
265	if (!pmu)
266		return -ENOMEM;
267
268	per_cpu(probed_pmus, cpu) = pmu;
 
 
 
269
270	if (pmu_irq_matches(pmu, irq)) {
271		hw_events = pmu->hw_events;
272		per_cpu(hw_events->irq, cpu) = irq;
273	}
274
275	cpumask_set_cpu(cpu, &pmu->supported_cpus);
276
277	/*
278	 * Ideally, we'd probe the PMU here when we find the first matching
279	 * CPU. We can't do that for several reasons; see the comment in
280	 * arm_pmu_acpi_init().
281	 *
282	 * So for the time being, we're done.
283	 */
284	return 0;
285}
286
287int arm_pmu_acpi_probe(armpmu_init_fn init_fn)
288{
289	int pmu_idx = 0;
290	int cpu, ret;
 
 
 
 
 
 
 
 
 
 
 
291
292	/*
293	 * Initialise and register the set of PMUs which we know about right
294	 * now. Ideally we'd do this in arm_pmu_acpi_cpu_starting() so that we
295	 * could handle late hotplug, but this may lead to deadlock since we
296	 * might try to register a hotplug notifier instance from within a
297	 * hotplug notifier.
298	 *
299	 * There's also the problem of having access to the right init_fn,
300	 * without tying this too deeply into the "real" PMU driver.
301	 *
302	 * For the moment, as with the platform/DT case, we need at least one
303	 * of a PMU's CPUs to be online at probe time.
304	 */
305	for_each_possible_cpu(cpu) {
306		struct arm_pmu *pmu = per_cpu(probed_pmus, cpu);
 
307		char *base_name;
308
309		if (!pmu || pmu->name)
 
310			continue;
311
 
 
 
 
 
 
 
 
 
 
 
 
312		ret = init_fn(pmu);
313		if (ret == -ENODEV) {
314			/* PMU not handled by this driver, or not present */
315			continue;
316		} else if (ret) {
317			pr_warn("Unable to initialise PMU for CPU%d\n", cpu);
318			return ret;
319		}
320
321		base_name = pmu->name;
322		pmu->name = kasprintf(GFP_KERNEL, "%s_%d", base_name, pmu_idx++);
323		if (!pmu->name) {
324			pr_warn("Unable to allocate PMU name for CPU%d\n", cpu);
325			return -ENOMEM;
326		}
327
328		ret = armpmu_register(pmu);
329		if (ret) {
330			pr_warn("Failed to register PMU for CPU%d\n", cpu);
331			kfree(pmu->name);
332			return ret;
333		}
334	}
335
336	return 0;
337}
338
339static int arm_pmu_acpi_init(void)
340{
341	int ret;
342
343	if (acpi_disabled)
344		return 0;
345
346	arm_spe_acpi_register_device();
 
347
348	ret = arm_pmu_acpi_parse_irqs();
349	if (ret)
350		return ret;
351
352	ret = cpuhp_setup_state(CPUHP_AP_PERF_ARM_ACPI_STARTING,
353				"perf/arm/pmu_acpi:starting",
354				arm_pmu_acpi_cpu_starting, NULL);
355
356	return ret;
357}
358subsys_initcall(arm_pmu_acpi_init)
v6.8
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * ACPI probing code for ARM performance counters.
  4 *
  5 * Copyright (C) 2017 ARM Ltd.
  6 */
  7
  8#include <linux/acpi.h>
  9#include <linux/cpumask.h>
 10#include <linux/init.h>
 11#include <linux/irq.h>
 12#include <linux/irqdesc.h>
 13#include <linux/percpu.h>
 14#include <linux/perf/arm_pmu.h>
 15
 16#include <asm/cpu.h>
 17#include <asm/cputype.h>
 18
 19static DEFINE_PER_CPU(struct arm_pmu *, probed_pmus);
 20static DEFINE_PER_CPU(int, pmu_irqs);
 21
 22static int arm_pmu_acpi_register_irq(int cpu)
 23{
 24	struct acpi_madt_generic_interrupt *gicc;
 25	int gsi, trigger;
 26
 27	gicc = acpi_cpu_get_madt_gicc(cpu);
 28
 29	gsi = gicc->performance_interrupt;
 30
 31	/*
 32	 * Per the ACPI spec, the MADT cannot describe a PMU that doesn't
 33	 * have an interrupt. QEMU advertises this by using a GSI of zero,
 34	 * which is not known to be valid on any hardware despite being
 35	 * valid per the spec. Take the pragmatic approach and reject a
 36	 * GSI of zero for now.
 37	 */
 38	if (!gsi)
 39		return 0;
 40
 41	if (gicc->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE)
 42		trigger = ACPI_EDGE_SENSITIVE;
 43	else
 44		trigger = ACPI_LEVEL_SENSITIVE;
 45
 46	/*
 47	 * Helpfully, the MADT GICC doesn't have a polarity flag for the
 48	 * "performance interrupt". Luckily, on compliant GICs the polarity is
 49	 * a fixed value in HW (for both SPIs and PPIs) that we cannot change
 50	 * from SW.
 51	 *
 52	 * Here we pass in ACPI_ACTIVE_HIGH to keep the core code happy. This
 53	 * may not match the real polarity, but that should not matter.
 54	 *
 55	 * Other interrupt controllers are not supported with ACPI.
 56	 */
 57	return acpi_register_gsi(NULL, gsi, trigger, ACPI_ACTIVE_HIGH);
 58}
 59
 60static void arm_pmu_acpi_unregister_irq(int cpu)
 61{
 62	struct acpi_madt_generic_interrupt *gicc;
 63	int gsi;
 64
 65	gicc = acpi_cpu_get_madt_gicc(cpu);
 66
 67	gsi = gicc->performance_interrupt;
 68	if (gsi)
 69		acpi_unregister_gsi(gsi);
 70}
 71
 72static int __maybe_unused
 73arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len,
 74			     u16 (*parse_gsi)(struct acpi_madt_generic_interrupt *))
 75{
 76	int cpu, this_hetid, hetid, irq, ret;
 77	u16 this_gsi = 0, gsi = 0;
 78
 79	/*
 80	 * Ensure that platform device must have IORESOURCE_IRQ
 81	 * resource to hold gsi interrupt.
 82	 */
 83	if (pdev->num_resources != 1)
 84		return -ENXIO;
 85
 86	if (pdev->resource[0].flags != IORESOURCE_IRQ)
 87		return -ENXIO;
 88
 89	/*
 90	 * Sanity check all the GICC tables for the same interrupt
 91	 * number. For now, only support homogeneous ACPI machines.
 92	 */
 93	for_each_possible_cpu(cpu) {
 94		struct acpi_madt_generic_interrupt *gicc;
 95
 96		gicc = acpi_cpu_get_madt_gicc(cpu);
 97		if (gicc->header.length < len)
 98			return gsi ? -ENXIO : 0;
 99
100		this_gsi = parse_gsi(gicc);
101		this_hetid = find_acpi_cpu_topology_hetero_id(cpu);
102		if (!gsi) {
103			hetid = this_hetid;
104			gsi = this_gsi;
105		} else if (hetid != this_hetid || gsi != this_gsi) {
106			pr_warn("ACPI: %s: must be homogeneous\n", pdev->name);
107			return -ENXIO;
108		}
109	}
110
111	if (!this_gsi)
112		return 0;
113
114	irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
115	if (irq < 0) {
116		pr_warn("ACPI: %s Unable to register interrupt: %d\n", pdev->name, gsi);
117		return -ENXIO;
118	}
119
120	pdev->resource[0].start = irq;
121	ret = platform_device_register(pdev);
122	if (ret)
123		acpi_unregister_gsi(gsi);
124
125	return ret;
126}
127
128#if IS_ENABLED(CONFIG_ARM_SPE_PMU)
129static struct resource spe_resources[] = {
130	{
131		/* irq */
132		.flags          = IORESOURCE_IRQ,
133	}
134};
135
136static struct platform_device spe_dev = {
137	.name = ARMV8_SPE_PDEV_NAME,
138	.id = -1,
139	.resource = spe_resources,
140	.num_resources = ARRAY_SIZE(spe_resources)
141};
142
143static u16 arm_spe_parse_gsi(struct acpi_madt_generic_interrupt *gicc)
144{
145	return gicc->spe_interrupt;
146}
147
148/*
149 * For lack of a better place, hook the normal PMU MADT walk
150 * and create a SPE device if we detect a recent MADT with
151 * a homogeneous PPI mapping.
152 */
153static void arm_spe_acpi_register_device(void)
154{
155	int ret = arm_acpi_register_pmu_device(&spe_dev, ACPI_MADT_GICC_SPE,
156					       arm_spe_parse_gsi);
157	if (ret)
158		pr_warn("ACPI: SPE: Unable to register device\n");
159}
160#else
161static inline void arm_spe_acpi_register_device(void)
162{
163}
164#endif /* CONFIG_ARM_SPE_PMU */
 
 
 
 
165
166#if IS_ENABLED(CONFIG_CORESIGHT_TRBE)
167static struct resource trbe_resources[] = {
168	{
169		/* irq */
170		.flags          = IORESOURCE_IRQ,
 
 
 
 
 
 
171	}
172};
173
174static struct platform_device trbe_dev = {
175	.name = ARMV8_TRBE_PDEV_NAME,
176	.id = -1,
177	.resource = trbe_resources,
178	.num_resources = ARRAY_SIZE(trbe_resources)
179};
180
181static u16 arm_trbe_parse_gsi(struct acpi_madt_generic_interrupt *gicc)
182{
183	return gicc->trbe_interrupt;
184}
185
186static void arm_trbe_acpi_register_device(void)
187{
188	int ret = arm_acpi_register_pmu_device(&trbe_dev, ACPI_MADT_GICC_TRBE,
189					       arm_trbe_parse_gsi);
190	if (ret)
191		pr_warn("ACPI: TRBE: Unable to register device\n");
192}
193#else
194static inline void arm_trbe_acpi_register_device(void)
195{
196
197}
198#endif /* CONFIG_CORESIGHT_TRBE */
199
200static int arm_pmu_acpi_parse_irqs(void)
201{
202	int irq, cpu, irq_cpu, err;
203
204	for_each_possible_cpu(cpu) {
205		irq = arm_pmu_acpi_register_irq(cpu);
206		if (irq < 0) {
207			err = irq;
208			pr_warn("Unable to parse ACPI PMU IRQ for CPU%d: %d\n",
209				cpu, err);
210			goto out_err;
211		} else if (irq == 0) {
212			pr_warn("No ACPI PMU IRQ for CPU%d\n", cpu);
213		}
214
215		/*
216		 * Log and request the IRQ so the core arm_pmu code can manage
217		 * it. We'll have to sanity-check IRQs later when we associate
218		 * them with their PMUs.
219		 */
220		per_cpu(pmu_irqs, cpu) = irq;
221		err = armpmu_request_irq(irq, cpu);
222		if (err)
223			goto out_err;
224	}
225
226	return 0;
227
228out_err:
229	for_each_possible_cpu(cpu) {
230		irq = per_cpu(pmu_irqs, cpu);
231		if (!irq)
232			continue;
233
234		arm_pmu_acpi_unregister_irq(cpu);
235
236		/*
237		 * Blat all copies of the IRQ so that we only unregister the
238		 * corresponding GSI once (e.g. when we have PPIs).
239		 */
240		for_each_possible_cpu(irq_cpu) {
241			if (per_cpu(pmu_irqs, irq_cpu) == irq)
242				per_cpu(pmu_irqs, irq_cpu) = 0;
243		}
244	}
245
246	return err;
247}
248
249static struct arm_pmu *arm_pmu_acpi_find_pmu(void)
250{
251	unsigned long cpuid = read_cpuid_id();
252	struct arm_pmu *pmu;
253	int cpu;
254
255	for_each_possible_cpu(cpu) {
256		pmu = per_cpu(probed_pmus, cpu);
257		if (!pmu || pmu->acpi_cpuid != cpuid)
258			continue;
259
260		return pmu;
261	}
262
263	return NULL;
 
 
 
 
 
 
 
 
 
264}
265
266/*
267 * Check whether the new IRQ is compatible with those already associated with
268 * the PMU (e.g. we don't have mismatched PPIs).
269 */
270static bool pmu_irq_matches(struct arm_pmu *pmu, int irq)
271{
272	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
273	int cpu;
274
275	if (!irq)
276		return true;
277
278	for_each_cpu(cpu, &pmu->supported_cpus) {
279		int other_irq = per_cpu(hw_events->irq, cpu);
280		if (!other_irq)
281			continue;
282
283		if (irq == other_irq)
284			continue;
285		if (!irq_is_percpu_devid(irq) && !irq_is_percpu_devid(other_irq))
286			continue;
287
288		pr_warn("mismatched PPIs detected\n");
289		return false;
290	}
291
292	return true;
293}
294
295static void arm_pmu_acpi_associate_pmu_cpu(struct arm_pmu *pmu,
296					   unsigned int cpu)
297{
298	int irq = per_cpu(pmu_irqs, cpu);
299
300	per_cpu(probed_pmus, cpu) = pmu;
301
302	if (pmu_irq_matches(pmu, irq)) {
303		struct pmu_hw_events __percpu *hw_events;
304		hw_events = pmu->hw_events;
305		per_cpu(hw_events->irq, cpu) = irq;
306	}
307
308	cpumask_set_cpu(cpu, &pmu->supported_cpus);
309}
310
311/*
312 * This must run before the common arm_pmu hotplug logic, so that we can
313 * associate a CPU and its interrupt before the common code tries to manage the
314 * affinity and so on.
315 *
316 * Note that hotplug events are serialized, so we cannot race with another CPU
317 * coming up. The perf core won't open events while a hotplug event is in
318 * progress.
319 */
320static int arm_pmu_acpi_cpu_starting(unsigned int cpu)
321{
322	struct arm_pmu *pmu;
 
 
323
324	/* If we've already probed this CPU, we have nothing to do */
325	if (per_cpu(probed_pmus, cpu))
326		return 0;
327
328	pmu = arm_pmu_acpi_find_pmu();
329	if (!pmu) {
330		pr_warn_ratelimited("Unable to associate CPU%d with a PMU\n",
331				    cpu);
332		return 0;
333	}
334
335	arm_pmu_acpi_associate_pmu_cpu(pmu, cpu);
336	return 0;
337}
338
339static void arm_pmu_acpi_probe_matching_cpus(struct arm_pmu *pmu,
340					     unsigned long cpuid)
341{
342	int cpu;
343
344	for_each_online_cpu(cpu) {
345		unsigned long cpu_cpuid = per_cpu(cpu_data, cpu).reg_midr;
 
 
346
347		if (cpu_cpuid == cpuid)
348			arm_pmu_acpi_associate_pmu_cpu(pmu, cpu);
349	}
 
 
 
 
 
 
 
350}
351
352int arm_pmu_acpi_probe(armpmu_init_fn init_fn)
353{
354	int pmu_idx = 0;
355	unsigned int cpu;
356	int ret;
357
358	ret = arm_pmu_acpi_parse_irqs();
359	if (ret)
360		return ret;
361
362	ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_ACPI_STARTING,
363					"perf/arm/pmu_acpi:starting",
364					arm_pmu_acpi_cpu_starting, NULL);
365	if (ret)
366		return ret;
367
368	/*
369	 * Initialise and register the set of PMUs which we know about right
370	 * now. Ideally we'd do this in arm_pmu_acpi_cpu_starting() so that we
371	 * could handle late hotplug, but this may lead to deadlock since we
372	 * might try to register a hotplug notifier instance from within a
373	 * hotplug notifier.
374	 *
375	 * There's also the problem of having access to the right init_fn,
376	 * without tying this too deeply into the "real" PMU driver.
377	 *
378	 * For the moment, as with the platform/DT case, we need at least one
379	 * of a PMU's CPUs to be online at probe time.
380	 */
381	for_each_online_cpu(cpu) {
382		struct arm_pmu *pmu = per_cpu(probed_pmus, cpu);
383		unsigned long cpuid;
384		char *base_name;
385
386		/* If we've already probed this CPU, we have nothing to do */
387		if (pmu)
388			continue;
389
390		pmu = armpmu_alloc();
391		if (!pmu) {
392			pr_warn("Unable to allocate PMU for CPU%d\n",
393				cpu);
394			return -ENOMEM;
395		}
396
397		cpuid = per_cpu(cpu_data, cpu).reg_midr;
398		pmu->acpi_cpuid = cpuid;
399
400		arm_pmu_acpi_probe_matching_cpus(pmu, cpuid);
401
402		ret = init_fn(pmu);
403		if (ret == -ENODEV) {
404			/* PMU not handled by this driver, or not present */
405			continue;
406		} else if (ret) {
407			pr_warn("Unable to initialise PMU for CPU%d\n", cpu);
408			return ret;
409		}
410
411		base_name = pmu->name;
412		pmu->name = kasprintf(GFP_KERNEL, "%s_%d", base_name, pmu_idx++);
413		if (!pmu->name) {
414			pr_warn("Unable to allocate PMU name for CPU%d\n", cpu);
415			return -ENOMEM;
416		}
417
418		ret = armpmu_register(pmu);
419		if (ret) {
420			pr_warn("Failed to register PMU for CPU%d\n", cpu);
421			kfree(pmu->name);
422			return ret;
423		}
424	}
425
426	return ret;
427}
428
429static int arm_pmu_acpi_init(void)
430{
 
 
431	if (acpi_disabled)
432		return 0;
433
434	arm_spe_acpi_register_device();
435	arm_trbe_acpi_register_device();
436
437	return 0;
 
 
 
 
 
 
 
 
438}
439subsys_initcall(arm_pmu_acpi_init)