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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
45736a72 MR |
2 | /* |
3 | * ACPI probing code for ARM performance counters. | |
4 | * | |
5 | * Copyright (C) 2017 ARM Ltd. | |
45736a72 MR |
6 | */ |
7 | ||
8 | #include <linux/acpi.h> | |
9 | #include <linux/cpumask.h> | |
10 | #include <linux/init.h> | |
43fc9a2f MR |
11 | #include <linux/irq.h> |
12 | #include <linux/irqdesc.h> | |
45736a72 MR |
13 | #include <linux/percpu.h> |
14 | #include <linux/perf/arm_pmu.h> | |
15 | ||
16 | #include <asm/cputype.h> | |
17 | ||
18 | static DEFINE_PER_CPU(struct arm_pmu *, probed_pmus); | |
19 | static DEFINE_PER_CPU(int, pmu_irqs); | |
20 | ||
21 | static 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 | if (WARN_ON(!gicc)) | |
28 | return -EINVAL; | |
29 | ||
30 | gsi = gicc->performance_interrupt; | |
477c50e8 WH |
31 | |
32 | /* | |
33 | * Per the ACPI spec, the MADT cannot describe a PMU that doesn't | |
34 | * have an interrupt. QEMU advertises this by using a GSI of zero, | |
35 | * which is not known to be valid on any hardware despite being | |
36 | * valid per the spec. Take the pragmatic approach and reject a | |
37 | * GSI of zero for now. | |
38 | */ | |
39 | if (!gsi) | |
40 | return 0; | |
41 | ||
45736a72 MR |
42 | if (gicc->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE) |
43 | trigger = ACPI_EDGE_SENSITIVE; | |
44 | else | |
45 | trigger = ACPI_LEVEL_SENSITIVE; | |
46 | ||
47 | /* | |
48 | * Helpfully, the MADT GICC doesn't have a polarity flag for the | |
49 | * "performance interrupt". Luckily, on compliant GICs the polarity is | |
50 | * a fixed value in HW (for both SPIs and PPIs) that we cannot change | |
51 | * from SW. | |
52 | * | |
53 | * Here we pass in ACPI_ACTIVE_HIGH to keep the core code happy. This | |
54 | * may not match the real polarity, but that should not matter. | |
55 | * | |
56 | * Other interrupt controllers are not supported with ACPI. | |
57 | */ | |
58 | return acpi_register_gsi(NULL, gsi, trigger, ACPI_ACTIVE_HIGH); | |
59 | } | |
60 | ||
61 | static void arm_pmu_acpi_unregister_irq(int cpu) | |
62 | { | |
63 | struct acpi_madt_generic_interrupt *gicc; | |
64 | int gsi; | |
65 | ||
66 | gicc = acpi_cpu_get_madt_gicc(cpu); | |
67 | if (!gicc) | |
68 | return; | |
69 | ||
70 | gsi = gicc->performance_interrupt; | |
71 | acpi_unregister_gsi(gsi); | |
72 | } | |
73 | ||
d24a0c70 JL |
74 | #if IS_ENABLED(CONFIG_ARM_SPE_PMU) |
75 | static struct resource spe_resources[] = { | |
76 | { | |
77 | /* irq */ | |
78 | .flags = IORESOURCE_IRQ, | |
79 | } | |
80 | }; | |
81 | ||
82 | static struct platform_device spe_dev = { | |
83 | .name = ARMV8_SPE_PDEV_NAME, | |
84 | .id = -1, | |
85 | .resource = spe_resources, | |
86 | .num_resources = ARRAY_SIZE(spe_resources) | |
87 | }; | |
88 | ||
89 | /* | |
90 | * For lack of a better place, hook the normal PMU MADT walk | |
91 | * and create a SPE device if we detect a recent MADT with | |
92 | * a homogeneous PPI mapping. | |
93 | */ | |
94 | static void arm_spe_acpi_register_device(void) | |
95 | { | |
96 | int cpu, hetid, irq, ret; | |
97 | bool first = true; | |
98 | u16 gsi = 0; | |
99 | ||
100 | /* | |
101 | * Sanity check all the GICC tables for the same interrupt number. | |
102 | * For now, we only support homogeneous ACPI/SPE machines. | |
103 | */ | |
104 | for_each_possible_cpu(cpu) { | |
105 | struct acpi_madt_generic_interrupt *gicc; | |
106 | ||
107 | gicc = acpi_cpu_get_madt_gicc(cpu); | |
108 | if (gicc->header.length < ACPI_MADT_GICC_SPE) | |
109 | return; | |
110 | ||
111 | if (first) { | |
112 | gsi = gicc->spe_interrupt; | |
113 | if (!gsi) | |
114 | return; | |
115 | hetid = find_acpi_cpu_topology_hetero_id(cpu); | |
116 | first = false; | |
117 | } else if ((gsi != gicc->spe_interrupt) || | |
118 | (hetid != find_acpi_cpu_topology_hetero_id(cpu))) { | |
119 | pr_warn("ACPI: SPE must be homogeneous\n"); | |
120 | return; | |
121 | } | |
122 | } | |
123 | ||
124 | irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, | |
125 | ACPI_ACTIVE_HIGH); | |
126 | if (irq < 0) { | |
127 | pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi); | |
128 | return; | |
129 | } | |
130 | ||
131 | spe_resources[0].start = irq; | |
132 | ret = platform_device_register(&spe_dev); | |
133 | if (ret < 0) { | |
134 | pr_warn("ACPI: SPE: Unable to register device\n"); | |
135 | acpi_unregister_gsi(gsi); | |
136 | } | |
137 | } | |
138 | #else | |
139 | static inline void arm_spe_acpi_register_device(void) | |
140 | { | |
141 | } | |
142 | #endif /* CONFIG_ARM_SPE_PMU */ | |
143 | ||
45736a72 MR |
144 | static int arm_pmu_acpi_parse_irqs(void) |
145 | { | |
146 | int irq, cpu, irq_cpu, err; | |
147 | ||
148 | for_each_possible_cpu(cpu) { | |
149 | irq = arm_pmu_acpi_register_irq(cpu); | |
150 | if (irq < 0) { | |
151 | err = irq; | |
152 | pr_warn("Unable to parse ACPI PMU IRQ for CPU%d: %d\n", | |
153 | cpu, err); | |
154 | goto out_err; | |
155 | } else if (irq == 0) { | |
156 | pr_warn("No ACPI PMU IRQ for CPU%d\n", cpu); | |
157 | } | |
158 | ||
167e6143 MR |
159 | /* |
160 | * Log and request the IRQ so the core arm_pmu code can manage | |
161 | * it. We'll have to sanity-check IRQs later when we associate | |
162 | * them with their PMUs. | |
163 | */ | |
45736a72 | 164 | per_cpu(pmu_irqs, cpu) = irq; |
167e6143 | 165 | armpmu_request_irq(irq, cpu); |
45736a72 MR |
166 | } |
167 | ||
168 | return 0; | |
169 | ||
170 | out_err: | |
171 | for_each_possible_cpu(cpu) { | |
172 | irq = per_cpu(pmu_irqs, cpu); | |
173 | if (!irq) | |
174 | continue; | |
175 | ||
176 | arm_pmu_acpi_unregister_irq(cpu); | |
177 | ||
178 | /* | |
179 | * Blat all copies of the IRQ so that we only unregister the | |
180 | * corresponding GSI once (e.g. when we have PPIs). | |
181 | */ | |
182 | for_each_possible_cpu(irq_cpu) { | |
183 | if (per_cpu(pmu_irqs, irq_cpu) == irq) | |
184 | per_cpu(pmu_irqs, irq_cpu) = 0; | |
185 | } | |
186 | } | |
187 | ||
188 | return err; | |
189 | } | |
190 | ||
191 | static struct arm_pmu *arm_pmu_acpi_find_alloc_pmu(void) | |
192 | { | |
193 | unsigned long cpuid = read_cpuid_id(); | |
194 | struct arm_pmu *pmu; | |
195 | int cpu; | |
196 | ||
197 | for_each_possible_cpu(cpu) { | |
198 | pmu = per_cpu(probed_pmus, cpu); | |
199 | if (!pmu || pmu->acpi_cpuid != cpuid) | |
200 | continue; | |
201 | ||
202 | return pmu; | |
203 | } | |
204 | ||
0dc1a185 | 205 | pmu = armpmu_alloc_atomic(); |
45736a72 MR |
206 | if (!pmu) { |
207 | pr_warn("Unable to allocate PMU for CPU%d\n", | |
208 | smp_processor_id()); | |
209 | return NULL; | |
210 | } | |
211 | ||
212 | pmu->acpi_cpuid = cpuid; | |
213 | ||
214 | return pmu; | |
215 | } | |
216 | ||
43fc9a2f MR |
217 | /* |
218 | * Check whether the new IRQ is compatible with those already associated with | |
219 | * the PMU (e.g. we don't have mismatched PPIs). | |
220 | */ | |
221 | static bool pmu_irq_matches(struct arm_pmu *pmu, int irq) | |
222 | { | |
223 | struct pmu_hw_events __percpu *hw_events = pmu->hw_events; | |
224 | int cpu; | |
225 | ||
226 | if (!irq) | |
227 | return true; | |
228 | ||
229 | for_each_cpu(cpu, &pmu->supported_cpus) { | |
230 | int other_irq = per_cpu(hw_events->irq, cpu); | |
231 | if (!other_irq) | |
232 | continue; | |
233 | ||
234 | if (irq == other_irq) | |
235 | continue; | |
236 | if (!irq_is_percpu_devid(irq) && !irq_is_percpu_devid(other_irq)) | |
237 | continue; | |
238 | ||
239 | pr_warn("mismatched PPIs detected\n"); | |
240 | return false; | |
241 | } | |
242 | ||
243 | return true; | |
244 | } | |
245 | ||
45736a72 MR |
246 | /* |
247 | * This must run before the common arm_pmu hotplug logic, so that we can | |
248 | * associate a CPU and its interrupt before the common code tries to manage the | |
249 | * affinity and so on. | |
250 | * | |
251 | * Note that hotplug events are serialized, so we cannot race with another CPU | |
252 | * coming up. The perf core won't open events while a hotplug event is in | |
253 | * progress. | |
254 | */ | |
255 | static int arm_pmu_acpi_cpu_starting(unsigned int cpu) | |
256 | { | |
257 | struct arm_pmu *pmu; | |
258 | struct pmu_hw_events __percpu *hw_events; | |
259 | int irq; | |
260 | ||
261 | /* If we've already probed this CPU, we have nothing to do */ | |
262 | if (per_cpu(probed_pmus, cpu)) | |
263 | return 0; | |
264 | ||
265 | irq = per_cpu(pmu_irqs, cpu); | |
266 | ||
267 | pmu = arm_pmu_acpi_find_alloc_pmu(); | |
268 | if (!pmu) | |
269 | return -ENOMEM; | |
270 | ||
45736a72 MR |
271 | per_cpu(probed_pmus, cpu) = pmu; |
272 | ||
43fc9a2f MR |
273 | if (pmu_irq_matches(pmu, irq)) { |
274 | hw_events = pmu->hw_events; | |
275 | per_cpu(hw_events->irq, cpu) = irq; | |
276 | } | |
277 | ||
278 | cpumask_set_cpu(cpu, &pmu->supported_cpus); | |
279 | ||
45736a72 MR |
280 | /* |
281 | * Ideally, we'd probe the PMU here when we find the first matching | |
282 | * CPU. We can't do that for several reasons; see the comment in | |
283 | * arm_pmu_acpi_init(). | |
284 | * | |
285 | * So for the time being, we're done. | |
286 | */ | |
287 | return 0; | |
288 | } | |
289 | ||
290 | int arm_pmu_acpi_probe(armpmu_init_fn init_fn) | |
291 | { | |
292 | int pmu_idx = 0; | |
293 | int cpu, ret; | |
294 | ||
45736a72 MR |
295 | /* |
296 | * Initialise and register the set of PMUs which we know about right | |
297 | * now. Ideally we'd do this in arm_pmu_acpi_cpu_starting() so that we | |
298 | * could handle late hotplug, but this may lead to deadlock since we | |
299 | * might try to register a hotplug notifier instance from within a | |
300 | * hotplug notifier. | |
301 | * | |
302 | * There's also the problem of having access to the right init_fn, | |
303 | * without tying this too deeply into the "real" PMU driver. | |
304 | * | |
305 | * For the moment, as with the platform/DT case, we need at least one | |
306 | * of a PMU's CPUs to be online at probe time. | |
307 | */ | |
308 | for_each_possible_cpu(cpu) { | |
309 | struct arm_pmu *pmu = per_cpu(probed_pmus, cpu); | |
310 | char *base_name; | |
311 | ||
312 | if (!pmu || pmu->name) | |
313 | continue; | |
314 | ||
315 | ret = init_fn(pmu); | |
316 | if (ret == -ENODEV) { | |
317 | /* PMU not handled by this driver, or not present */ | |
318 | continue; | |
319 | } else if (ret) { | |
320 | pr_warn("Unable to initialise PMU for CPU%d\n", cpu); | |
321 | return ret; | |
322 | } | |
323 | ||
324 | base_name = pmu->name; | |
325 | pmu->name = kasprintf(GFP_KERNEL, "%s_%d", base_name, pmu_idx++); | |
326 | if (!pmu->name) { | |
327 | pr_warn("Unable to allocate PMU name for CPU%d\n", cpu); | |
328 | return -ENOMEM; | |
329 | } | |
330 | ||
331 | ret = armpmu_register(pmu); | |
332 | if (ret) { | |
333 | pr_warn("Failed to register PMU for CPU%d\n", cpu); | |
a88dc7ba | 334 | kfree(pmu->name); |
45736a72 MR |
335 | return ret; |
336 | } | |
337 | } | |
338 | ||
339 | return 0; | |
340 | } | |
341 | ||
342 | static int arm_pmu_acpi_init(void) | |
343 | { | |
344 | int ret; | |
345 | ||
346 | if (acpi_disabled) | |
347 | return 0; | |
348 | ||
d24a0c70 JL |
349 | arm_spe_acpi_register_device(); |
350 | ||
45736a72 MR |
351 | ret = arm_pmu_acpi_parse_irqs(); |
352 | if (ret) | |
353 | return ret; | |
354 | ||
355 | ret = cpuhp_setup_state(CPUHP_AP_PERF_ARM_ACPI_STARTING, | |
356 | "perf/arm/pmu_acpi:starting", | |
357 | arm_pmu_acpi_cpu_starting, NULL); | |
358 | ||
359 | return ret; | |
360 | } | |
361 | subsys_initcall(arm_pmu_acpi_init) |