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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); | |
45736a72 MR |
27 | |
28 | gsi = gicc->performance_interrupt; | |
477c50e8 WH |
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 | ||
45736a72 MR |
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 | ||
59 | static 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); | |
45736a72 MR |
65 | |
66 | gsi = gicc->performance_interrupt; | |
3ba52ad5 | 67 | if (gsi) |
68 | acpi_unregister_gsi(gsi); | |
45736a72 MR |
69 | } |
70 | ||
d24a0c70 JL |
71 | #if IS_ENABLED(CONFIG_ARM_SPE_PMU) |
72 | static struct resource spe_resources[] = { | |
73 | { | |
74 | /* irq */ | |
75 | .flags = IORESOURCE_IRQ, | |
76 | } | |
77 | }; | |
78 | ||
79 | static 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 | */ | |
91 | static 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 | |
136 | static inline void arm_spe_acpi_register_device(void) | |
137 | { | |
138 | } | |
139 | #endif /* CONFIG_ARM_SPE_PMU */ | |
140 | ||
45736a72 MR |
141 | static 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 | ||
167e6143 MR |
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 | */ | |
45736a72 | 161 | per_cpu(pmu_irqs, cpu) = irq; |
167e6143 | 162 | armpmu_request_irq(irq, cpu); |
45736a72 MR |
163 | } |
164 | ||
165 | return 0; | |
166 | ||
167 | out_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 | ||
188 | static 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 | ||
0dc1a185 | 202 | pmu = armpmu_alloc_atomic(); |
45736a72 MR |
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 | ||
43fc9a2f MR |
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 | */ | |
218 | static 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 | ||
45736a72 MR |
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 | */ | |
252 | static 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 | ||
45736a72 MR |
268 | per_cpu(probed_pmus, cpu) = pmu; |
269 | ||
43fc9a2f MR |
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 | ||
45736a72 MR |
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 | ||
287 | int arm_pmu_acpi_probe(armpmu_init_fn init_fn) | |
288 | { | |
289 | int pmu_idx = 0; | |
290 | int cpu, ret; | |
291 | ||
45736a72 MR |
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); | |
a88dc7ba | 331 | kfree(pmu->name); |
45736a72 MR |
332 | return ret; |
333 | } | |
334 | } | |
335 | ||
336 | return 0; | |
337 | } | |
338 | ||
339 | static int arm_pmu_acpi_init(void) | |
340 | { | |
341 | int ret; | |
342 | ||
343 | if (acpi_disabled) | |
344 | return 0; | |
345 | ||
d24a0c70 JL |
346 | arm_spe_acpi_register_device(); |
347 | ||
45736a72 MR |
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 | } | |
358 | subsys_initcall(arm_pmu_acpi_init) |