summaryrefslogtreecommitdiffstats
path: root/drivers/perf/arm_pmu_acpi.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/perf/arm_pmu_acpi.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/perf/arm_pmu_acpi.c')
-rw-r--r--drivers/perf/arm_pmu_acpi.c360
1 files changed, 360 insertions, 0 deletions
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
new file mode 100644
index 000000000..96ffadd65
--- /dev/null
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ACPI probing code for ARM performance counters.
+ *
+ * Copyright (C) 2017 ARM Ltd.
+ */
+
+#include <linux/acpi.h>
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+#include <linux/percpu.h>
+#include <linux/perf/arm_pmu.h>
+
+#include <asm/cputype.h>
+
+static DEFINE_PER_CPU(struct arm_pmu *, probed_pmus);
+static DEFINE_PER_CPU(int, pmu_irqs);
+
+static int arm_pmu_acpi_register_irq(int cpu)
+{
+ struct acpi_madt_generic_interrupt *gicc;
+ int gsi, trigger;
+
+ gicc = acpi_cpu_get_madt_gicc(cpu);
+
+ gsi = gicc->performance_interrupt;
+
+ /*
+ * Per the ACPI spec, the MADT cannot describe a PMU that doesn't
+ * have an interrupt. QEMU advertises this by using a GSI of zero,
+ * which is not known to be valid on any hardware despite being
+ * valid per the spec. Take the pragmatic approach and reject a
+ * GSI of zero for now.
+ */
+ if (!gsi)
+ return 0;
+
+ if (gicc->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE)
+ trigger = ACPI_EDGE_SENSITIVE;
+ else
+ trigger = ACPI_LEVEL_SENSITIVE;
+
+ /*
+ * Helpfully, the MADT GICC doesn't have a polarity flag for the
+ * "performance interrupt". Luckily, on compliant GICs the polarity is
+ * a fixed value in HW (for both SPIs and PPIs) that we cannot change
+ * from SW.
+ *
+ * Here we pass in ACPI_ACTIVE_HIGH to keep the core code happy. This
+ * may not match the real polarity, but that should not matter.
+ *
+ * Other interrupt controllers are not supported with ACPI.
+ */
+ return acpi_register_gsi(NULL, gsi, trigger, ACPI_ACTIVE_HIGH);
+}
+
+static void arm_pmu_acpi_unregister_irq(int cpu)
+{
+ struct acpi_madt_generic_interrupt *gicc;
+ int gsi;
+
+ gicc = acpi_cpu_get_madt_gicc(cpu);
+
+ gsi = gicc->performance_interrupt;
+ if (gsi)
+ acpi_unregister_gsi(gsi);
+}
+
+#if IS_ENABLED(CONFIG_ARM_SPE_PMU)
+static struct resource spe_resources[] = {
+ {
+ /* irq */
+ .flags = IORESOURCE_IRQ,
+ }
+};
+
+static struct platform_device spe_dev = {
+ .name = ARMV8_SPE_PDEV_NAME,
+ .id = -1,
+ .resource = spe_resources,
+ .num_resources = ARRAY_SIZE(spe_resources)
+};
+
+/*
+ * For lack of a better place, hook the normal PMU MADT walk
+ * and create a SPE device if we detect a recent MADT with
+ * a homogeneous PPI mapping.
+ */
+static void arm_spe_acpi_register_device(void)
+{
+ int cpu, hetid, irq, ret;
+ bool first = true;
+ u16 gsi = 0;
+
+ /*
+ * Sanity check all the GICC tables for the same interrupt number.
+ * For now, we only support homogeneous ACPI/SPE machines.
+ */
+ for_each_possible_cpu(cpu) {
+ struct acpi_madt_generic_interrupt *gicc;
+
+ gicc = acpi_cpu_get_madt_gicc(cpu);
+ if (gicc->header.length < ACPI_MADT_GICC_SPE)
+ return;
+
+ if (first) {
+ gsi = gicc->spe_interrupt;
+ if (!gsi)
+ return;
+ hetid = find_acpi_cpu_topology_hetero_id(cpu);
+ first = false;
+ } else if ((gsi != gicc->spe_interrupt) ||
+ (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {
+ pr_warn("ACPI: SPE must be homogeneous\n");
+ return;
+ }
+ }
+
+ irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE,
+ ACPI_ACTIVE_HIGH);
+ if (irq < 0) {
+ pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi);
+ return;
+ }
+
+ spe_resources[0].start = irq;
+ ret = platform_device_register(&spe_dev);
+ if (ret < 0) {
+ pr_warn("ACPI: SPE: Unable to register device\n");
+ acpi_unregister_gsi(gsi);
+ }
+}
+#else
+static inline void arm_spe_acpi_register_device(void)
+{
+}
+#endif /* CONFIG_ARM_SPE_PMU */
+
+static int arm_pmu_acpi_parse_irqs(void)
+{
+ int irq, cpu, irq_cpu, err;
+
+ for_each_possible_cpu(cpu) {
+ irq = arm_pmu_acpi_register_irq(cpu);
+ if (irq < 0) {
+ err = irq;
+ pr_warn("Unable to parse ACPI PMU IRQ for CPU%d: %d\n",
+ cpu, err);
+ goto out_err;
+ } else if (irq == 0) {
+ pr_warn("No ACPI PMU IRQ for CPU%d\n", cpu);
+ }
+
+ /*
+ * Log and request the IRQ so the core arm_pmu code can manage
+ * it. We'll have to sanity-check IRQs later when we associate
+ * them with their PMUs.
+ */
+ per_cpu(pmu_irqs, cpu) = irq;
+ err = armpmu_request_irq(irq, cpu);
+ if (err)
+ goto out_err;
+ }
+
+ return 0;
+
+out_err:
+ for_each_possible_cpu(cpu) {
+ irq = per_cpu(pmu_irqs, cpu);
+ if (!irq)
+ continue;
+
+ arm_pmu_acpi_unregister_irq(cpu);
+
+ /*
+ * Blat all copies of the IRQ so that we only unregister the
+ * corresponding GSI once (e.g. when we have PPIs).
+ */
+ for_each_possible_cpu(irq_cpu) {
+ if (per_cpu(pmu_irqs, irq_cpu) == irq)
+ per_cpu(pmu_irqs, irq_cpu) = 0;
+ }
+ }
+
+ return err;
+}
+
+static struct arm_pmu *arm_pmu_acpi_find_alloc_pmu(void)
+{
+ unsigned long cpuid = read_cpuid_id();
+ struct arm_pmu *pmu;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ pmu = per_cpu(probed_pmus, cpu);
+ if (!pmu || pmu->acpi_cpuid != cpuid)
+ continue;
+
+ return pmu;
+ }
+
+ pmu = armpmu_alloc_atomic();
+ if (!pmu) {
+ pr_warn("Unable to allocate PMU for CPU%d\n",
+ smp_processor_id());
+ return NULL;
+ }
+
+ pmu->acpi_cpuid = cpuid;
+
+ return pmu;
+}
+
+/*
+ * Check whether the new IRQ is compatible with those already associated with
+ * the PMU (e.g. we don't have mismatched PPIs).
+ */
+static bool pmu_irq_matches(struct arm_pmu *pmu, int irq)
+{
+ struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
+ int cpu;
+
+ if (!irq)
+ return true;
+
+ for_each_cpu(cpu, &pmu->supported_cpus) {
+ int other_irq = per_cpu(hw_events->irq, cpu);
+ if (!other_irq)
+ continue;
+
+ if (irq == other_irq)
+ continue;
+ if (!irq_is_percpu_devid(irq) && !irq_is_percpu_devid(other_irq))
+ continue;
+
+ pr_warn("mismatched PPIs detected\n");
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * This must run before the common arm_pmu hotplug logic, so that we can
+ * associate a CPU and its interrupt before the common code tries to manage the
+ * affinity and so on.
+ *
+ * Note that hotplug events are serialized, so we cannot race with another CPU
+ * coming up. The perf core won't open events while a hotplug event is in
+ * progress.
+ */
+static int arm_pmu_acpi_cpu_starting(unsigned int cpu)
+{
+ struct arm_pmu *pmu;
+ struct pmu_hw_events __percpu *hw_events;
+ int irq;
+
+ /* If we've already probed this CPU, we have nothing to do */
+ if (per_cpu(probed_pmus, cpu))
+ return 0;
+
+ irq = per_cpu(pmu_irqs, cpu);
+
+ pmu = arm_pmu_acpi_find_alloc_pmu();
+ if (!pmu)
+ return -ENOMEM;
+
+ per_cpu(probed_pmus, cpu) = pmu;
+
+ if (pmu_irq_matches(pmu, irq)) {
+ hw_events = pmu->hw_events;
+ per_cpu(hw_events->irq, cpu) = irq;
+ }
+
+ cpumask_set_cpu(cpu, &pmu->supported_cpus);
+
+ /*
+ * Ideally, we'd probe the PMU here when we find the first matching
+ * CPU. We can't do that for several reasons; see the comment in
+ * arm_pmu_acpi_init().
+ *
+ * So for the time being, we're done.
+ */
+ return 0;
+}
+
+int arm_pmu_acpi_probe(armpmu_init_fn init_fn)
+{
+ int pmu_idx = 0;
+ int cpu, ret;
+
+ /*
+ * Initialise and register the set of PMUs which we know about right
+ * now. Ideally we'd do this in arm_pmu_acpi_cpu_starting() so that we
+ * could handle late hotplug, but this may lead to deadlock since we
+ * might try to register a hotplug notifier instance from within a
+ * hotplug notifier.
+ *
+ * There's also the problem of having access to the right init_fn,
+ * without tying this too deeply into the "real" PMU driver.
+ *
+ * For the moment, as with the platform/DT case, we need at least one
+ * of a PMU's CPUs to be online at probe time.
+ */
+ for_each_possible_cpu(cpu) {
+ struct arm_pmu *pmu = per_cpu(probed_pmus, cpu);
+ char *base_name;
+
+ if (!pmu || pmu->name)
+ continue;
+
+ ret = init_fn(pmu);
+ if (ret == -ENODEV) {
+ /* PMU not handled by this driver, or not present */
+ continue;
+ } else if (ret) {
+ pr_warn("Unable to initialise PMU for CPU%d\n", cpu);
+ return ret;
+ }
+
+ base_name = pmu->name;
+ pmu->name = kasprintf(GFP_KERNEL, "%s_%d", base_name, pmu_idx++);
+ if (!pmu->name) {
+ pr_warn("Unable to allocate PMU name for CPU%d\n", cpu);
+ return -ENOMEM;
+ }
+
+ ret = armpmu_register(pmu);
+ if (ret) {
+ pr_warn("Failed to register PMU for CPU%d\n", cpu);
+ kfree(pmu->name);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static int arm_pmu_acpi_init(void)
+{
+ int ret;
+
+ if (acpi_disabled)
+ return 0;
+
+ arm_spe_acpi_register_device();
+
+ ret = arm_pmu_acpi_parse_irqs();
+ if (ret)
+ return ret;
+
+ ret = cpuhp_setup_state(CPUHP_AP_PERF_ARM_ACPI_STARTING,
+ "perf/arm/pmu_acpi:starting",
+ arm_pmu_acpi_cpu_starting, NULL);
+
+ return ret;
+}
+subsys_initcall(arm_pmu_acpi_init)