Re: [PATCH v6] soc: qcom: add l2 cache perf events driver
From: Neil Leeder
Date: Tue Oct 04 2016 - 10:35:22 EST
On 9/21/2016 05:12 PM, Neil Leeder wrote:
> Adds perf events support for L2 cache PMU.
>
> The L2 cache PMU driver is named 'l2cache_0' and can be used
> with perf events to profile L2 events such as cache hits
> and misses.
>
> Signed-off-by: Neil Leeder <nleeder@xxxxxxxxxxxxxx>
> ---
> v6: restore accidentally dropped Kconfig dependencies
>
> v5:
> Fold the header and l2-accessors into .c file
> Use multi-instance framework for hotplug
> Change terminology from slice to cluster for clarity
> Remove unnecessary rmw sequence for enable registers
> Use prev_count in hwc rather than in slice
> Enforce all events in same group on same CPU
> Add comments, rename variables for clarity
>
> v4:
> Replace notifier with hotplug statemachine
> Allocate PMU struct dynamically
>
> v3:
> Remove exports from l2-accessors
> Change l2-accessors Kconfig to make it not user-selectable
> Reorder and remove unnecessary includes
>
> v2:
> Add the l2-accessors patch to this patchset, previously posted separately.
> Remove sampling and per-task functionality for this uncore PMU.
> Use cpumask to replace code which filtered events to one cpu per slice.
> Replace manual event filtering with filter_match callback.
> Use a separate used_mask for event groups.
> Add hotplug notifier for CPU and irq migration.
> Remove extraneous synchronisation instructions.
> Other miscellaneous cleanup.
>
> drivers/soc/qcom/Kconfig | 9 +
> drivers/soc/qcom/Makefile | 1 +
> drivers/soc/qcom/perf_event_l2.c | 948 +++++++++++++++++++++++++++++++++++++++
> include/linux/cpuhotplug.h | 1 +
> 4 files changed, 959 insertions(+)
> create mode 100644 drivers/soc/qcom/perf_event_l2.c
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index 461b387..3fa27a8 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -10,6 +10,15 @@ config QCOM_GSBI
> functions for connecting the underlying serial UART, SPI, and I2C
> devices to the output pins.
>
> +config QCOM_PERF_EVENTS_L2
> + bool "Qualcomm Technologies L2-cache perf events"
> + depends on ARCH_QCOM && ARM64 && HW_PERF_EVENTS && ACPI
> + help
> + Provides support for the L2 cache performance monitor unit (PMU)
> + in Qualcomm Technologies processors.
> + Adds the L2 cache PMU into the perf events subsystem for
> + monitoring L2 cache events.
> +
> config QCOM_PM
> bool "Qualcomm Power Management"
> depends on ARCH_QCOM && !ARM64
> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
> index fdd664e..4c9df3b 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -1,4 +1,5 @@
> obj-$(CONFIG_QCOM_GSBI) += qcom_gsbi.o
> +obj-$(CONFIG_QCOM_PERF_EVENTS_L2) += perf_event_l2.o
> obj-$(CONFIG_QCOM_PM) += spm.o
> obj-$(CONFIG_QCOM_SMD) += smd.o
> obj-$(CONFIG_QCOM_SMD_RPM) += smd-rpm.o
> diff --git a/drivers/soc/qcom/perf_event_l2.c b/drivers/soc/qcom/perf_event_l2.c
> new file mode 100644
> index 0000000..bbf47c9
> --- /dev/null
> +++ b/drivers/soc/qcom/perf_event_l2.c
> @@ -0,0 +1,948 @@
> +/* Copyright (c) 2015,2016 The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +#include <linux/acpi.h>
> +#include <linux/interrupt.h>
> +#include <linux/perf_event.h>
> +#include <linux/platform_device.h>
> +
> +#define MAX_L2_CTRS 9
> +
> +#define L2PMCR_NUM_EV_SHIFT 11
> +#define L2PMCR_NUM_EV_MASK 0x1F
> +
> +#define L2PMCR 0x400
> +#define L2PMCNTENCLR 0x403
> +#define L2PMCNTENSET 0x404
> +#define L2PMINTENCLR 0x405
> +#define L2PMINTENSET 0x406
> +#define L2PMOVSCLR 0x407
> +#define L2PMOVSSET 0x408
> +#define L2PMCCNTCR 0x409
> +#define L2PMCCNTR 0x40A
> +#define L2PMCCNTSR 0x40C
> +#define L2PMRESR 0x410
> +#define IA_L2PMXEVCNTCR_BASE 0x420
> +#define IA_L2PMXEVCNTR_BASE 0x421
> +#define IA_L2PMXEVFILTER_BASE 0x423
> +#define IA_L2PMXEVTYPER_BASE 0x424
> +
> +#define IA_L2_REG_OFFSET 0x10
> +
> +#define L2PMXEVFILTER_SUFILTER_ALL 0x000E0000
> +#define L2PMXEVFILTER_ORGFILTER_IDINDEP 0x00000004
> +#define L2PMXEVFILTER_ORGFILTER_ALL 0x00000003
> +
> +#define L2PM_CC_ENABLE 0x80000000
> +
> +#define L2EVTYPER_REG_SHIFT 3
> +
> +#define L2PMRESR_GROUP_BITS 8
> +#define L2PMRESR_GROUP_MASK GENMASK(7, 0)
> +
> +#define L2CYCLE_CTR_BIT 31
> +#define L2CYCLE_CTR_RAW_CODE 0xFE
> +
> +#define L2PMCR_RESET_ALL 0x6
> +#define L2PMCR_COUNTERS_ENABLE 0x1
> +#define L2PMCR_COUNTERS_DISABLE 0x0
> +
> +#define L2PMRESR_EN ((u64)1 << 63)
> +
> +#define L2_EVT_MASK 0x00000FFF
> +#define L2_EVT_CODE_MASK 0x00000FF0
> +#define L2_EVT_GRP_MASK 0x0000000F
> +#define L2_EVT_CODE_SHIFT 4
> +#define L2_EVT_GRP_SHIFT 0
> +
> +#define L2_EVT_CODE(event) (((event) & L2_EVT_CODE_MASK) >> L2_EVT_CODE_SHIFT)
> +#define L2_EVT_GROUP(event) (((event) & L2_EVT_GRP_MASK) >> L2_EVT_GRP_SHIFT)
> +
> +#define L2_EVT_GROUP_MAX 7
> +
> +#define L2_MAX_PERIOD U32_MAX
> +#define L2_CNT_PERIOD (U32_MAX - GENMASK(26, 0))
> +
> +#define L2CPUSRSELR_EL1 S3_3_c15_c0_6
> +#define L2CPUSRDR_EL1 S3_3_c15_c0_7
> +
> +static DEFINE_RAW_SPINLOCK(l2_access_lock);
> +
> +/**
> + * set_l2_indirect_reg: write value to an L2 register
> + * @reg: Address of L2 register.
> + * @value: Value to be written to register.
> + *
> + * Use architecturally required barriers for ordering between system register
> + * accesses
> + */
> +static void set_l2_indirect_reg(u64 reg, u64 val)
> +{
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&l2_access_lock, flags);
> + write_sysreg(reg, L2CPUSRSELR_EL1);
> + isb();
> + write_sysreg(val, L2CPUSRDR_EL1);
> + isb();
> + raw_spin_unlock_irqrestore(&l2_access_lock, flags);
> +}
> +
> +/**
> + * get_l2_indirect_reg: read an L2 register value
> + * @reg: Address of L2 register.
> + *
> + * Use architecturally required barriers for ordering between system register
> + * accesses
> + */
> +static u64 get_l2_indirect_reg(u64 reg)
> +{
> + u64 val;
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&l2_access_lock, flags);
> + write_sysreg(reg, L2CPUSRSELR_EL1);
> + isb();
> + val = read_sysreg(L2CPUSRDR_EL1);
> + raw_spin_unlock_irqrestore(&l2_access_lock, flags);
> +
> + return val;
> +}
> +
> +/*
> + * Aggregate PMU. Implements the core pmu functions and manages
> + * the hardware PMUs.
> + */
> +struct l2cache_pmu {
> + struct hlist_node node;
> + u32 num_pmus;
> + struct pmu pmu;
> + int num_counters;
> + cpumask_t cpumask;
> + struct platform_device *pdev;
> +};
> +
> +/*
> + * The cache is made up of one or more clusters, each cluster has its own PMU.
> + * Each cluster is associated with one or more CPUs.
> + * This structure represents one of the hardware PMUs.
> + *
> + * Events can be envisioned as a 2-dimensional array. Each column represents
> + * a group of events. There are 8 groups. Only one entry from each
> + * group can be in use at a time. When an event is assigned a counter
> + * by *_event_add(), the counter index is assigned to group_to_counter[group].
> + * This allows *filter_match() to detect and reject conflicting events in
> + * the same group.
> + * Events are specified as 0xCCG, where CC is 2 hex digits specifying
> + * the code (array row) and G specifies the group (column).
> + *
> + * In addition there is a cycle counter event specified by L2CYCLE_CTR_RAW_CODE
> + * which is outside the above scheme.
> + */
> +struct hml2_pmu {
> + struct perf_event *events[MAX_L2_CTRS];
> + struct l2cache_pmu *l2cache_pmu;
> + DECLARE_BITMAP(used_counters, MAX_L2_CTRS);
> + DECLARE_BITMAP(used_groups, L2_EVT_GROUP_MAX + 1);
> + int group_to_counter[L2_EVT_GROUP_MAX + 1];
> + int irq;
> + /* The CPU that is used for collecting events on this cluster */
> + int on_cpu;
> + /* All the CPUs associated with this cluster */
> + cpumask_t cluster_cpus;
> + spinlock_t pmu_lock;
> +};
> +
> +#define to_l2cache_pmu(p) (container_of(p, struct l2cache_pmu, pmu))
> +
> +static DEFINE_PER_CPU(struct hml2_pmu *, pmu_cluster);
> +static u32 l2_cycle_ctr_idx;
> +static u32 l2_counter_present_mask;
> +
> +static inline u32 idx_to_reg_bit(u32 idx)
> +{
> + if (idx == l2_cycle_ctr_idx)
> + return BIT(L2CYCLE_CTR_BIT);
> +
> + return BIT(idx);
> +}
> +
> +static inline struct hml2_pmu *get_hml2_pmu(int cpu)
> +{
> + return per_cpu(pmu_cluster, cpu);
> +}
> +
> +static void hml2_pmu__reset_on_cluster(void *x)
> +{
> + /* Reset all ctrs */
> + set_l2_indirect_reg(L2PMCR, L2PMCR_RESET_ALL);
> + set_l2_indirect_reg(L2PMCNTENCLR, l2_counter_present_mask);
> + set_l2_indirect_reg(L2PMINTENCLR, l2_counter_present_mask);
> + set_l2_indirect_reg(L2PMOVSCLR, l2_counter_present_mask);
> +}
> +
> +static inline void hml2_pmu__reset(struct hml2_pmu *cluster)
> +{
> + cpumask_t *mask = &cluster->cluster_cpus;
> +
> + if (smp_call_function_any(mask, hml2_pmu__reset_on_cluster, NULL, 1))
> + dev_err(&cluster->l2cache_pmu->pdev->dev,
> + "Failed to reset on cluster with cpu %d\n",
> + cpumask_first(&cluster->cluster_cpus));
> +}
> +
> +static inline void hml2_pmu__enable(void)
> +{
> + set_l2_indirect_reg(L2PMCR, L2PMCR_COUNTERS_ENABLE);
> +}
> +
> +static inline void hml2_pmu__disable(void)
> +{
> + set_l2_indirect_reg(L2PMCR, L2PMCR_COUNTERS_DISABLE);
> +}
> +
> +static inline void hml2_pmu__counter_set_value(u32 idx, u64 value)
> +{
> + u32 counter_reg;
> +
> + if (idx == l2_cycle_ctr_idx) {
> + set_l2_indirect_reg(L2PMCCNTR, value);
> + } else {
> + counter_reg = (idx * IA_L2_REG_OFFSET) + IA_L2PMXEVCNTR_BASE;
> + set_l2_indirect_reg(counter_reg, value & GENMASK(31, 0));
> + }
> +}
> +
> +static inline u64 hml2_pmu__counter_get_value(u32 idx)
> +{
> + u64 value;
> + u32 counter_reg;
> +
> + if (idx == l2_cycle_ctr_idx) {
> + value = get_l2_indirect_reg(L2PMCCNTR);
> + } else {
> + counter_reg = (idx * IA_L2_REG_OFFSET) + IA_L2PMXEVCNTR_BASE;
> + value = get_l2_indirect_reg(counter_reg);
> + }
> +
> + return value;
> +}
> +
> +static inline void hml2_pmu__counter_enable(u32 idx)
> +{
> + set_l2_indirect_reg(L2PMCNTENSET, idx_to_reg_bit(idx));
> +}
> +
> +static inline void hml2_pmu__counter_disable(u32 idx)
> +{
> + set_l2_indirect_reg(L2PMCNTENCLR, idx_to_reg_bit(idx));
> +}
> +
> +static inline void hml2_pmu__counter_enable_interrupt(u32 idx)
> +{
> + set_l2_indirect_reg(L2PMINTENSET, idx_to_reg_bit(idx));
> +}
> +
> +static inline void hml2_pmu__counter_disable_interrupt(u32 idx)
> +{
> + set_l2_indirect_reg(L2PMINTENCLR, idx_to_reg_bit(idx));
> +}
> +
> +static inline void hml2_pmu__set_evccntcr(u32 val)
> +{
> + set_l2_indirect_reg(L2PMCCNTCR, val);
> +}
> +
> +static inline void hml2_pmu__set_evcntcr(u32 ctr, u32 val)
> +{
> + u32 evtcr_reg = (ctr * IA_L2_REG_OFFSET) + IA_L2PMXEVCNTCR_BASE;
> +
> + set_l2_indirect_reg(evtcr_reg, val);
> +}
> +
> +static inline void hml2_pmu__set_evtyper(u32 ctr, u32 val)
> +{
> + u32 evtype_reg = (ctr * IA_L2_REG_OFFSET) + IA_L2PMXEVTYPER_BASE;
> +
> + set_l2_indirect_reg(evtype_reg, val);
> +}
> +
> +static void hml2_pmu__set_resr(struct hml2_pmu *cluster,
> + u32 event_group, u32 event_cc)
> +{
> + u64 field;
> + u64 resr_val;
> + u32 shift;
> + unsigned long flags;
> +
> + shift = L2PMRESR_GROUP_BITS * event_group;
> + field = ((u64)(event_cc & L2PMRESR_GROUP_MASK) << shift) | L2PMRESR_EN;
> +
> + spin_lock_irqsave(&cluster->pmu_lock, flags);
> +
> + resr_val = get_l2_indirect_reg(L2PMRESR);
> + resr_val &= ~(L2PMRESR_GROUP_MASK << shift);
> + resr_val |= field;
> + set_l2_indirect_reg(L2PMRESR, resr_val);
> +
> + spin_unlock_irqrestore(&cluster->pmu_lock, flags);
> +}
> +
> +/*
> + * Hardware allows filtering of events based on the originating
> + * CPU. Turn this off by setting filter bits to allow events from
> + * all CPUS, subunits and ID independent events in this cluster.
> + */
> +static inline void hml2_pmu__set_evfilter_sys_mode(u32 ctr)
> +{
> + u32 reg = (ctr * IA_L2_REG_OFFSET) + IA_L2PMXEVFILTER_BASE;
> + u32 val = L2PMXEVFILTER_SUFILTER_ALL |
> + L2PMXEVFILTER_ORGFILTER_IDINDEP |
> + L2PMXEVFILTER_ORGFILTER_ALL;
> +
> + set_l2_indirect_reg(reg, val);
> +}
> +
> +static inline u32 hml2_pmu__getreset_ovsr(void)
> +{
> + u32 result = get_l2_indirect_reg(L2PMOVSSET);
> +
> + set_l2_indirect_reg(L2PMOVSCLR, result);
> + return result;
> +}
> +
> +static inline bool hml2_pmu__has_overflowed(u32 ovsr)
> +{
> + return !!(ovsr & l2_counter_present_mask);
> +}
> +
> +static inline bool hml2_pmu__counter_has_overflowed(u32 ovsr, u32 idx)
> +{
> + return !!(ovsr & idx_to_reg_bit(idx));
> +}
> +
> +static void l2_cache__event_update_from_cluster(struct perf_event *event,
> + struct hml2_pmu *cluster)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + u64 delta64, prev, now;
> + u32 delta;
> + u32 idx = hwc->idx;
> +
> + do {
> + prev = local64_read(&hwc->prev_count);
> + now = hml2_pmu__counter_get_value(idx);
> + } while (local64_cmpxchg(&hwc->prev_count, prev, now) != prev);
> +
> + if (idx == l2_cycle_ctr_idx) {
> + /*
> + * The cycle counter is 64-bit so needs separate handling
> + * of 64-bit delta.
> + */
> + delta64 = now - prev;
> + local64_add(delta64, &event->count);
> + } else {
> + /*
> + * 32-bit counters need the unsigned 32-bit math to handle
> + * overflow and now < prev
> + */
> + delta = now - prev;
> + local64_add(delta, &event->count);
> + }
> +}
> +
> +static void l2_cache__cluster_set_period(struct hml2_pmu *cluster,
> + struct hw_perf_event *hwc)
> +{
> + u64 base = L2_MAX_PERIOD - (L2_CNT_PERIOD - 1);
> + u32 idx = hwc->idx;
> + u64 prev = local64_read(&hwc->prev_count);
> + u64 value;
> +
> + /*
> + * Limit the maximum period to prevent the counter value
> + * from overtaking the one we are about to program.
> + * Use a starting value which is high enough that after
> + * an overflow, interrupt latency will not cause the count
> + * to reach the base value. If the previous value
> + * is below the base, increase it to be above the base
> + * and update prev_count accordingly. Otherwise if
> + * the previous value is already above the base
> + * nothing needs to be done to prev_count.
> + */
> + if (prev < base) {
> + value = base + prev;
> + local64_set(&hwc->prev_count, value);
> + } else {
> + value = prev;
> + }
> +
> + hml2_pmu__counter_set_value(idx, value);
> +}
> +
> +static int l2_cache__get_event_idx(struct hml2_pmu *cluster,
> + struct perf_event *event)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + int idx;
> +
> + if (hwc->config_base == L2CYCLE_CTR_RAW_CODE) {
> + if (test_and_set_bit(l2_cycle_ctr_idx, cluster->used_counters))
> + return -EAGAIN;
> +
> + return l2_cycle_ctr_idx;
> + }
> +
> + for (idx = 0; idx < cluster->l2cache_pmu->num_counters - 1; idx++) {
> + if (!test_and_set_bit(idx, cluster->used_counters)) {
> + set_bit(L2_EVT_GROUP(hwc->config_base),
> + cluster->used_groups);
> + return idx;
> + }
> + }
> +
> + /* The counters are all in use. */
> + return -EAGAIN;
> +}
> +
> +static void l2_cache__clear_event_idx(struct hml2_pmu *cluster,
> + struct perf_event *event)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + int idx = hwc->idx;
> +
> + clear_bit(idx, cluster->used_counters);
> + if (hwc->config_base != L2CYCLE_CTR_RAW_CODE)
> + clear_bit(L2_EVT_GROUP(hwc->config_base), cluster->used_groups);
> +}
> +
> +static irqreturn_t l2_cache__handle_irq(int irq_num, void *data)
> +{
> + struct hml2_pmu *cluster = data;
> + int num_counters = cluster->l2cache_pmu->num_counters;
> + u32 ovsr;
> + int idx;
> +
> + ovsr = hml2_pmu__getreset_ovsr();
> + if (!hml2_pmu__has_overflowed(ovsr))
> + return IRQ_NONE;
> +
> + for_each_set_bit(idx, cluster->used_counters, num_counters) {
> + struct perf_event *event = cluster->events[idx];
> + struct hw_perf_event *hwc;
> +
> + if (!hml2_pmu__counter_has_overflowed(ovsr, idx))
> + continue;
> +
> + l2_cache__event_update_from_cluster(event, cluster);
> + hwc = &event->hw;
> +
> + l2_cache__cluster_set_period(cluster, hwc);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +/*
> + * Implementation of abstract pmu functionality required by
> + * the core perf events code.
> + */
> +
> +static void l2_cache__pmu_enable(struct pmu *pmu)
> +{
> + /*
> + * Although there is only one PMU (per socket) controlling multiple
> + * physical PMUs (per cluster), because we do not support per-task mode
> + * each event is associated with a CPU. Each event has pmu_enable
> + * called on its CPU, so here it is only necessary to enable the
> + * counters for the current CPU.
> + */
> +
> + hml2_pmu__enable();
> +}
> +
> +static void l2_cache__pmu_disable(struct pmu *pmu)
> +{
> + hml2_pmu__disable();
> +}
> +
> +static int l2_cache__event_init(struct perf_event *event)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + struct hml2_pmu *cluster;
> + struct perf_event *sibling;
> + struct l2cache_pmu *l2cache_pmu;
> +
> + if (event->attr.type != event->pmu->type)
> + return -ENOENT;
> +
> + l2cache_pmu = to_l2cache_pmu(event->pmu);
> +
> + if (hwc->sample_period) {
> + dev_warn(&l2cache_pmu->pdev->dev, "Sampling not supported\n");
> + return -EOPNOTSUPP;
> + }
> +
> + if (event->cpu < 0) {
> + dev_warn(&l2cache_pmu->pdev->dev, "Per-task mode not supported\n");
> + return -EOPNOTSUPP;
> + }
> +
> + /* We cannot filter accurately so we just don't allow it. */
> + if (event->attr.exclude_user || event->attr.exclude_kernel ||
> + event->attr.exclude_hv || event->attr.exclude_idle) {
> + dev_warn(&l2cache_pmu->pdev->dev, "Can't exclude execution levels\n");
> + return -EOPNOTSUPP;
> + }
> +
> + if (((L2_EVT_GROUP(event->attr.config) > L2_EVT_GROUP_MAX) ||
> + ((event->attr.config & ~L2_EVT_MASK) != 0)) &&
> + (event->attr.config != L2CYCLE_CTR_RAW_CODE)) {
> + dev_warn(&l2cache_pmu->pdev->dev, "Invalid config %llx\n",
> + event->attr.config);
> + return -EINVAL;
> + }
> +
> + /* Don't allow groups with mixed PMUs, except for s/w events */
> + if (event->group_leader->pmu != event->pmu &&
> + !is_software_event(event->group_leader)) {
> + dev_warn(&l2cache_pmu->pdev->dev,
> + "Can't create mixed PMU group\n");
> + return -EINVAL;
> + }
> +
> + list_for_each_entry(sibling, &event->group_leader->sibling_list,
> + group_entry)
> + if (sibling->pmu != event->pmu &&
> + !is_software_event(sibling)) {
> + dev_warn(&l2cache_pmu->pdev->dev,
> + "Can't create mixed PMU group\n");
> + return -EINVAL;
> + }
> +
> + /* Ensure all events in a group are on the same cpu */
> + cluster = get_hml2_pmu(event->cpu);
> + if ((event->group_leader != event) &&
> + (cluster->on_cpu != event->group_leader->cpu)) {
> + dev_warn(&l2cache_pmu->pdev->dev,
> + "Can't create group on CPUs %d and %d",
> + event->cpu, event->group_leader->cpu);
> + return -EINVAL;
> + }
> +
> + hwc->idx = -1;
> + hwc->config_base = event->attr.config;
> +
> + /*
> + * Ensure all events are on the same cpu so all events are in the
> + * same cpu context, to avoid races on pmu_enable etc.
> + */
> + event->cpu = cluster->on_cpu;
> +
> + return 0;
> +}
> +
> +static void l2_cache__event_start(struct perf_event *event, int flags)
> +{
> + struct hml2_pmu *cluster;
> + struct hw_perf_event *hwc = &event->hw;
> + int idx = hwc->idx;
> + u32 config;
> + u32 event_cc, event_group;
> +
> + hwc->state = 0;
> +
> + cluster = get_hml2_pmu(event->cpu);
> + l2_cache__cluster_set_period(cluster, hwc);
> +
> + if (hwc->config_base == L2CYCLE_CTR_RAW_CODE) {
> + hml2_pmu__set_evccntcr(0x0);
> + } else {
> + config = hwc->config_base;
> + event_cc = L2_EVT_CODE(config);
> + event_group = L2_EVT_GROUP(config);
> +
> + hml2_pmu__set_evcntcr(idx, 0x0);
> + hml2_pmu__set_evtyper(idx, event_group);
> + hml2_pmu__set_resr(cluster, event_group, event_cc);
> + hml2_pmu__set_evfilter_sys_mode(idx);
> + }
> +
> + hml2_pmu__counter_enable_interrupt(idx);
> + hml2_pmu__counter_enable(idx);
> +}
> +
> +static void l2_cache__event_stop(struct perf_event *event, int flags)
> +{
> + struct hml2_pmu *cluster;
> + struct hw_perf_event *hwc = &event->hw;
> + int idx = hwc->idx;
> +
> + if (!(hwc->state & PERF_HES_STOPPED)) {
> + cluster = get_hml2_pmu(event->cpu);
> + hml2_pmu__counter_disable_interrupt(idx);
> + hml2_pmu__counter_disable(idx);
> +
> + if (flags & PERF_EF_UPDATE)
> + l2_cache__event_update_from_cluster(event, cluster);
> + hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
> + }
> +}
> +
> +static int l2_cache__event_add(struct perf_event *event, int flags)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + int idx;
> + int err = 0;
> + struct hml2_pmu *cluster;
> +
> + cluster = get_hml2_pmu(event->cpu);
> +
> + idx = l2_cache__get_event_idx(cluster, event);
> + if (idx < 0) {
> + err = idx;
> + return err;
> + }
> +
> + hwc->idx = idx;
> + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> + cluster->events[idx] = event;
> + cluster->group_to_counter[L2_EVT_GROUP(hwc->config_base)] = idx;
> + local64_set(&hwc->prev_count, 0ULL);
> +
> + if (flags & PERF_EF_START)
> + l2_cache__event_start(event, flags);
> +
> + /* Propagate changes to the userspace mapping. */
> + perf_event_update_userpage(event);
> +
> + return err;
> +}
> +
> +static void l2_cache__event_del(struct perf_event *event, int flags)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + struct hml2_pmu *cluster;
> + int idx = hwc->idx;
> +
> + cluster = get_hml2_pmu(event->cpu);
> + l2_cache__event_stop(event, flags | PERF_EF_UPDATE);
> + cluster->events[idx] = NULL;
> + l2_cache__clear_event_idx(cluster, event);
> +
> + perf_event_update_userpage(event);
> +}
> +
> +static void l2_cache__event_read(struct perf_event *event)
> +{
> + l2_cache__event_update_from_cluster(event, get_hml2_pmu(event->cpu));
> +}
> +
> +static int l2_cache_filter_match(struct perf_event *event)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + struct hml2_pmu *cluster = get_hml2_pmu(event->cpu);
> + unsigned int group = L2_EVT_GROUP(hwc->config_base);
> +
> + /* check for column exclusion: group already in use by another event */
> + if (test_bit(group, cluster->used_groups) &&
> + cluster->events[cluster->group_to_counter[group]] != event)
> + return 0;
> +
> + return 1;
> +}
> +
> +static ssize_t l2_cache_pmu_cpumask_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct l2cache_pmu *l2cache_pmu = to_l2cache_pmu(dev_get_drvdata(dev));
> +
> + return cpumap_print_to_pagebuf(true, buf, &l2cache_pmu->cpumask);
> +}
> +
> +static struct device_attribute l2_cache_pmu_cpumask_attr =
> + __ATTR(cpumask, S_IRUGO, l2_cache_pmu_cpumask_show, NULL);
> +
> +static struct attribute *l2_cache_pmu_cpumask_attrs[] = {
> + &l2_cache_pmu_cpumask_attr.attr,
> + NULL,
> +};
> +
> +static struct attribute_group l2_cache_pmu_cpumask_group = {
> + .attrs = l2_cache_pmu_cpumask_attrs,
> +};
> +
> +/* CCG format for perf RAW codes. */
> +PMU_FORMAT_ATTR(l2_code, "config:4-11");
> +PMU_FORMAT_ATTR(l2_group, "config:0-3");
> +static struct attribute *l2_cache_pmu_formats[] = {
> + &format_attr_l2_code.attr,
> + &format_attr_l2_group.attr,
> + NULL,
> +};
> +
> +static struct attribute_group l2_cache_pmu_format_group = {
> + .name = "format",
> + .attrs = l2_cache_pmu_formats,
> +};
> +
> +static const struct attribute_group *l2_cache_pmu_attr_grps[] = {
> + &l2_cache_pmu_format_group,
> + &l2_cache_pmu_cpumask_group,
> + NULL,
> +};
> +
> +/*
> + * Generic device handlers
> + */
> +
> +static const struct acpi_device_id l2_cache_pmu_acpi_match[] = {
> + { "QCOM8130", },
> + { }
> +};
> +
> +static int get_num_counters(void)
> +{
> + int val;
> +
> + val = get_l2_indirect_reg(L2PMCR);
> +
> + /*
> + * Read number of counters from L2PMCR and add 1
> + * for the cycle counter.
> + */
> + return ((val >> L2PMCR_NUM_EV_SHIFT) & L2PMCR_NUM_EV_MASK) + 1;
> +}
> +
> +static int l2cache_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)
> +{
> + struct hml2_pmu *cluster;
> + cpumask_t cluster_online_cpus;
> + struct l2cache_pmu *l2cache_pmu;
> +
> + l2cache_pmu = hlist_entry_safe(node, struct l2cache_pmu, node);
> + cluster = get_hml2_pmu(cpu);
> + cpumask_and(&cluster_online_cpus, &cluster->cluster_cpus,
> + cpu_online_mask);
> +
> + if (cpumask_weight(&cluster_online_cpus) == 1) {
> + /* all CPUs on this cluster were down, use this one */
> + cluster->on_cpu = cpu;
> + cpumask_set_cpu(cpu, &l2cache_pmu->cpumask);
> + WARN_ON(irq_set_affinity(cluster->irq, cpumask_of(cpu)));
> + }
> +
> + return 0;
> +}
> +
> +static int l2cache_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
> +{
> + struct hml2_pmu *cluster;
> + struct l2cache_pmu *l2cache_pmu;
> + cpumask_t cluster_online_cpus;
> + unsigned int target;
> +
> + l2cache_pmu = hlist_entry_safe(node, struct l2cache_pmu, node);
> +
> + if (!cpumask_test_and_clear_cpu(cpu, &l2cache_pmu->cpumask))
> + return 0;
> + cluster = get_hml2_pmu(cpu);
> + cpumask_and(&cluster_online_cpus, &cluster->cluster_cpus,
> + cpu_online_mask);
> +
> + /* Any other CPU for this cluster which is still online */
> + target = cpumask_any_but(&cluster_online_cpus, cpu);
> + if (target >= nr_cpu_ids)
> + return 0;
> +
> + perf_pmu_migrate_context(&l2cache_pmu->pmu, cpu, target);
> + cluster->on_cpu = target;
> + cpumask_set_cpu(target, &l2cache_pmu->cpumask);
> + WARN_ON(irq_set_affinity(cluster->irq, cpumask_of(target)));
> +
> + return 0;
> +}
> +
> +static int l2_cache_pmu_probe_cluster(struct device *dev, void *data)
> +{
> + struct platform_device *pdev = to_platform_device(dev->parent);
> + struct platform_device *sdev = to_platform_device(dev);
> + struct l2cache_pmu *l2cache_pmu = data;
> + struct hml2_pmu *cluster;
> + struct acpi_device *device;
> + unsigned long fw_cluster_id;
> + int cpu;
> + int err;
> + int irq;
> +
> + if (acpi_bus_get_device(ACPI_HANDLE(dev), &device))
> + return -ENODEV;
> +
> + if (kstrtol(device->pnp.unique_id, 10, &fw_cluster_id) < 0) {
> + dev_err(&pdev->dev, "unable to read ACPI uid\n");
> + return -ENODEV;
> + }
> +
> + irq = platform_get_irq(sdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev,
> + "Failed to get valid irq for cluster %ld\n",
> + fw_cluster_id);
> + return irq;
> + }
> +
> + cluster = devm_kzalloc(&pdev->dev, sizeof(*cluster), GFP_KERNEL);
> + if (!cluster)
> + return -ENOMEM;
> +
> + cluster->l2cache_pmu = l2cache_pmu;
> + for_each_present_cpu(cpu) {
> + if (topology_physical_package_id(cpu) == fw_cluster_id) {
> + cpumask_set_cpu(cpu, &cluster->cluster_cpus);
> + per_cpu(pmu_cluster, cpu) = cluster;
> + }
> + }
> + cluster->irq = irq;
> +
> + if (cpumask_empty(&cluster->cluster_cpus)) {
> + dev_err(&pdev->dev, "No CPUs found for L2 cache instance %ld\n",
> + fw_cluster_id);
> + return -ENODEV;
> + }
> +
> + /* Pick one CPU to be the preferred one to use in the cluster */
> + cluster->on_cpu = cpumask_first(&cluster->cluster_cpus);
> +
> + if (irq_set_affinity(irq, cpumask_of(cluster->on_cpu))) {
> + dev_err(&pdev->dev,
> + "Unable to set irq affinity (irq=%d, cpu=%d)\n",
> + irq, cluster->on_cpu);
> + return -ENODEV;
> + }
> +
> + err = devm_request_irq(&pdev->dev, irq, l2_cache__handle_irq,
> + IRQF_NOBALANCING, "l2-cache-pmu", cluster);
> + if (err) {
> + dev_err(&pdev->dev,
> + "Unable to request IRQ%d for L2 PMU counters\n", irq);
> + return err;
> + }
> +
> + dev_info(&pdev->dev,
> + "Registered L2 cache PMU instance %ld with %d CPUs\n",
> + fw_cluster_id, cpumask_weight(&cluster->cluster_cpus));
> +
> + cluster->pmu_lock = __SPIN_LOCK_UNLOCKED(cluster->pmu_lock);
> + cpumask_set_cpu(cluster->on_cpu, &l2cache_pmu->cpumask);
> +
> + hml2_pmu__reset(cluster);
> + l2cache_pmu->num_pmus++;
> +
> + return 0;
> +}
> +
> +static int l2_cache_pmu_probe(struct platform_device *pdev)
> +{
> + int err;
> + struct l2cache_pmu *l2cache_pmu;
> +
> + l2cache_pmu =
> + devm_kzalloc(&pdev->dev, sizeof(*l2cache_pmu), GFP_KERNEL);
> + if (!l2cache_pmu)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, l2cache_pmu);
> + l2cache_pmu->pmu = (struct pmu) {
> + /* suffix is instance id for future use with multiple sockets */
> + .name = "l2cache_0",
> + .task_ctx_nr = perf_invalid_context,
> + .pmu_enable = l2_cache__pmu_enable,
> + .pmu_disable = l2_cache__pmu_disable,
> + .event_init = l2_cache__event_init,
> + .add = l2_cache__event_add,
> + .del = l2_cache__event_del,
> + .start = l2_cache__event_start,
> + .stop = l2_cache__event_stop,
> + .read = l2_cache__event_read,
> + .attr_groups = l2_cache_pmu_attr_grps,
> + .filter_match = l2_cache_filter_match,
> + };
> +
> + l2cache_pmu->num_counters = get_num_counters();
> + l2cache_pmu->pdev = pdev;
> + l2_cycle_ctr_idx = l2cache_pmu->num_counters - 1;
> + l2_counter_present_mask = GENMASK(l2cache_pmu->num_counters - 2, 0) |
> + L2PM_CC_ENABLE;
> +
> + cpumask_clear(&l2cache_pmu->cpumask);
> +
> + /* Read cluster info and initialize each cluster */
> + err = device_for_each_child(&pdev->dev, l2cache_pmu,
> + l2_cache_pmu_probe_cluster);
> + if (err < 0)
> + return err;
> +
> + if (l2cache_pmu->num_pmus == 0) {
> + dev_err(&pdev->dev, "No hardware L2 cache PMUs found\n");
> + return -ENODEV;
> + }
> +
> + err = perf_pmu_register(&l2cache_pmu->pmu, l2cache_pmu->pmu.name, -1);
> + if (err < 0) {
> + dev_err(&pdev->dev, "Error %d registering L2 cache PMU\n", err);
> + return err;
> + }
> +
> + dev_info(&pdev->dev, "Registered L2 cache PMU using %d HW PMUs\n",
> + l2cache_pmu->num_pmus);
> +
> + err = cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
> + &l2cache_pmu->node);
> +
> + return err;
> +}
> +
> +static int l2_cache_pmu_remove(struct platform_device *pdev)
> +{
> + struct l2cache_pmu *l2cache_pmu =
> + to_l2cache_pmu(platform_get_drvdata(pdev));
> +
> + cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
> + &l2cache_pmu->node);
> + perf_pmu_unregister(&l2cache_pmu->pmu);
> + return 0;
> +}
> +
> +static struct platform_driver l2_cache_pmu_driver = {
> + .driver = {
> + .name = "qcom-l2cache-pmu",
> + .owner = THIS_MODULE,
> + .acpi_match_table = ACPI_PTR(l2_cache_pmu_acpi_match),
> + },
> + .probe = l2_cache_pmu_probe,
> + .remove = l2_cache_pmu_remove,
> +};
> +
> +static int __init register_l2_cache_pmu_driver(void)
> +{
> + int err;
> +
> + err = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
> + "AP_PERF_ARM_QCOM_L2_ONLINE",
> + l2cache_pmu_online_cpu,
> + l2cache_pmu_offline_cpu);
> + if (err)
> + return err;
> +
> + return platform_driver_register(&l2_cache_pmu_driver);
> +}
> +device_initcall(register_l2_cache_pmu_driver);
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index 45a4287..f342842 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -113,6 +113,7 @@ enum cpuhp_state {
> CPUHP_AP_PERF_ARM_CCI_ONLINE,
> CPUHP_AP_PERF_ARM_CCN_ONLINE,
> CPUHP_AP_PERF_ARM_L2X0_ONLINE,
> + CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
> CPUHP_AP_WORKQUEUE_ONLINE,
> CPUHP_AP_RCUTREE_ONLINE,
> CPUHP_AP_NOTIFY_ONLINE,
>
I believe this addresses all the issues raised previously - are there any other comments? Thanks.
Neil
--
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a Linux Foundation Collaborative Project.