drivers/perf/arm_pmu_acpi.c

   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
  19 static DEFINE_PER_CPU(struct arm_pmu *, probed_pmus);
  20 static DEFINE_PER_CPU(int, pmu_irqs);
  21
  22 static 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
  60 static 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
  72 static int __maybe_unused
  73 arm_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)
 129 static struct resource spe_resources[] = {
 130         {
 131                 /* irq */
 132                 .flags          = IORESOURCE_IRQ,
 133         }
 134 };
 135
 136 static 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
 143 static 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  */
 153 static 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
 161 static inline void arm_spe_acpi_register_device(void)
 162 {
 163 }
 164 #endif /* CONFIG_ARM_SPE_PMU */
 165
 166 #if IS_ENABLED(CONFIG_CORESIGHT_TRBE)
 167 static struct resource trbe_resources[] = {
 168         {
 169                 /* irq */
 170                 .flags          = IORESOURCE_IRQ,
 171         }
 172 };
 173
 174 static 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
 181 static u16 arm_trbe_parse_gsi(struct acpi_madt_generic_interrupt *gicc)
 182 {
 183         return gicc->trbe_interrupt;
 184 }
 185
 186 static 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
 194 static inline void arm_trbe_acpi_register_device(void)
 195 {
 196
 197 }
 198 #endif /* CONFIG_CORESIGHT_TRBE */
 199
 200 static 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
 228 out_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
 249 static 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  */
 270 static 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
 295 static 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  */
 320 static 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
 339 static 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
 352 int 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
 429 static 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 }
 439 subsys_initcall(arm_pmu_acpi_init)