drivers/base/arch_topology.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Arch specific cpu topology information
 *
 * Copyright (C) 2016, ARM Ltd.
 * Written by: Juri Lelli, ARM Ltd.
 */

#include <linux/acpi.h>
#include <linux/cacheinfo.h>
#include <linux/cleanup.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpu_smt.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/sched/topology.h>
#include <linux/cpuset.h>
#include <linux/cpumask.h>
#include <linux/init.h>
#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/units.h>

#define CREATE_TRACE_POINTS
#include <trace/events/hw_pressure.h>

static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data);
static struct cpumask scale_freq_counters_mask;
static bool scale_freq_invariant;
DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 0;
EXPORT_PER_CPU_SYMBOL_GPL(capacity_freq_ref);

static bool supports_scale_freq_counters(const struct cpumask *cpus)
{
	int i;

	for_each_cpu(i, cpus) {
		if (cpumask_test_cpu(i, &scale_freq_counters_mask))
			return true;
	}

	return false;
}

bool topology_scale_freq_invariant(void)
{
	return cpufreq_supports_freq_invariance() ||
	       supports_scale_freq_counters(cpu_online_mask);
}

static void update_scale_freq_invariant(bool status)
{
	if (scale_freq_invariant == status)
		return;

	/*
	 * Task scheduler behavior depends on frequency invariance support,
	 * either cpufreq or counter driven. If the support status changes as
	 * a result of counter initialisation and use, retrigger the build of
	 * scheduling domains to ensure the information is propagated properly.
	 */
	if (topology_scale_freq_invariant() == status) {
		scale_freq_invariant = status;
		rebuild_sched_domains_energy();
	}
}

void topology_set_scale_freq_source(struct scale_freq_data *data,
				    const struct cpumask *cpus)
{
	struct scale_freq_data *sfd;
	int cpu;

	/*
	 * Avoid calling rebuild_sched_domains() unnecessarily if FIE is
	 * supported by cpufreq.
	 */
	if (cpumask_empty(&scale_freq_counters_mask))
		scale_freq_invariant = topology_scale_freq_invariant();

	rcu_read_lock();

	for_each_cpu(cpu, cpus) {
		sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));

		/* Use ARCH provided counters whenever possible */
		if (!sfd || sfd->source != SCALE_FREQ_SOURCE_ARCH) {
			rcu_assign_pointer(per_cpu(sft_data, cpu), data);
			cpumask_set_cpu(cpu, &scale_freq_counters_mask);
		}
	}

	rcu_read_unlock();

	update_scale_freq_invariant(true);
}
EXPORT_SYMBOL_GPL(topology_set_scale_freq_source);

void topology_clear_scale_freq_source(enum scale_freq_source source,
				      const struct cpumask *cpus)
{
	struct scale_freq_data *sfd;
	int cpu;

	rcu_read_lock();

	for_each_cpu(cpu, cpus) {
		sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));

		if (sfd && sfd->source == source) {
			rcu_assign_pointer(per_cpu(sft_data, cpu), NULL);
			cpumask_clear_cpu(cpu, &scale_freq_counters_mask);
		}
	}

	rcu_read_unlock();

	/*
	 * Make sure all references to previous sft_data are dropped to avoid
	 * use-after-free races.
	 */
	synchronize_rcu();

	update_scale_freq_invariant(false);
}
EXPORT_SYMBOL_GPL(topology_clear_scale_freq_source);

void topology_scale_freq_tick(void)
{
	struct scale_freq_data *sfd = rcu_dereference_sched(*this_cpu_ptr(&sft_data));

	if (sfd)
		sfd->set_freq_scale();
}

DEFINE_PER_CPU(unsigned long, arch_freq_scale) = SCHED_CAPACITY_SCALE;
EXPORT_PER_CPU_SYMBOL_GPL(arch_freq_scale);

void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
			     unsigned long max_freq)
{
	unsigned long scale;
	int i;

	if (WARN_ON_ONCE(!cur_freq || !max_freq))
		return;

	/*
	 * If the use of counters for FIE is enabled, just return as we don't
	 * want to update the scale factor with information from CPUFREQ.
	 * Instead the scale factor will be updated from arch_scale_freq_tick.
	 */
	if (supports_scale_freq_counters(cpus))
		return;

	scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;

	for_each_cpu(i, cpus)
		per_cpu(arch_freq_scale, i) = scale;
}

DEFINE_PER_CPU(unsigned long, hw_pressure);

/**
 * topology_update_hw_pressure() - Update HW pressure for CPUs
 * @cpus        : The related CPUs for which capacity has been reduced
 * @capped_freq : The maximum allowed frequency that CPUs can run at
 *
 * Update the value of HW pressure for all @cpus in the mask. The
 * cpumask should include all (online+offline) affected CPUs, to avoid
 * operating on stale data when hot-plug is used for some CPUs. The
 * @capped_freq reflects the currently allowed max CPUs frequency due to
 * HW capping. It might be also a boost frequency value, which is bigger
 * than the internal 'capacity_freq_ref' max frequency. In such case the
 * pressure value should simply be removed, since this is an indication that
 * there is no HW throttling. The @capped_freq must be provided in kHz.
 */
void topology_update_hw_pressure(const struct cpumask *cpus,
				      unsigned long capped_freq)
{
	unsigned long max_capacity, capacity, pressure;
	u32 max_freq;
	int cpu;

	cpu = cpumask_first(cpus);
	max_capacity = arch_scale_cpu_capacity(cpu);
	max_freq = arch_scale_freq_ref(cpu);

	/*
	 * Handle properly the boost frequencies, which should simply clean
	 * the HW pressure value.
	 */
	if (max_freq <= capped_freq)
		capacity = max_capacity;
	else
		capacity = mult_frac(max_capacity, capped_freq, max_freq);

	pressure = max_capacity - capacity;

	trace_hw_pressure_update(cpu, pressure);

	for_each_cpu(cpu, cpus)
		WRITE_ONCE(per_cpu(hw_pressure, cpu), pressure);
}
EXPORT_SYMBOL_GPL(topology_update_hw_pressure);

static void update_topology_flags_workfn(struct work_struct *work);
static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn);

static int update_topology;

int topology_update_cpu_topology(void)
{
	return update_topology;
}

/*
 * Updating the sched_domains can't be done directly from cpufreq callbacks
 * due to locking, so queue the work for later.
 */
static void update_topology_flags_workfn(struct work_struct *work)
{
	update_topology = 1;
	rebuild_sched_domains();
	pr_debug("sched_domain hierarchy rebuilt, flags updated\n");
	update_topology = 0;
}

static u32 *raw_capacity;

static int free_raw_capacity(void)
{
	kfree(raw_capacity);
	raw_capacity = NULL;

	return 0;
}

void topology_normalize_cpu_scale(void)
{
	u64 capacity;
	u64 capacity_scale;
	int cpu;

	if (!raw_capacity)
		return;

	capacity_scale = 1;
	for_each_possible_cpu(cpu) {
		capacity = raw_capacity[cpu] *
			   (per_cpu(capacity_freq_ref, cpu) ?: 1);
		capacity_scale = max(capacity, capacity_scale);
	}

	pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale);
	for_each_possible_cpu(cpu) {
		capacity = raw_capacity[cpu] *
			   (per_cpu(capacity_freq_ref, cpu) ?: 1);
		capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
			capacity_scale);
		topology_set_cpu_scale(cpu, capacity);
		pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
			cpu, topology_get_cpu_scale(cpu));
	}
}

bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
{
	struct clk *cpu_clk;
	static bool cap_parsing_failed;
	int ret;
	u32 cpu_capacity;

	if (cap_parsing_failed)
		return false;

	ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
				   &cpu_capacity);
	if (!ret) {
		if (!raw_capacity) {
			raw_capacity = kcalloc(num_possible_cpus(),
					       sizeof(*raw_capacity),
					       GFP_KERNEL);
			if (!raw_capacity) {
				cap_parsing_failed = true;
				return false;
			}
		}
		raw_capacity[cpu] = cpu_capacity;
		pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
			cpu_node, raw_capacity[cpu]);

		/*
		 * Update capacity_freq_ref for calculating early boot CPU capacities.
		 * For non-clk CPU DVFS mechanism, there's no way to get the
		 * frequency value now, assuming they are running at the same
		 * frequency (by keeping the initial capacity_freq_ref value).
		 */
		cpu_clk = of_clk_get(cpu_node, 0);
		if (!IS_ERR_OR_NULL(cpu_clk)) {
			per_cpu(capacity_freq_ref, cpu) =
				clk_get_rate(cpu_clk) / HZ_PER_KHZ;
			clk_put(cpu_clk);
		}
	} else {
		if (raw_capacity) {
			pr_err("cpu_capacity: missing %pOF raw capacity\n",
				cpu_node);
			pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
		}
		cap_parsing_failed = true;
		free_raw_capacity();
	}

	return !ret;
}

void __weak freq_inv_set_max_ratio(int cpu, u64 max_rate)
{
}

#ifdef CONFIG_ACPI_CPPC_LIB
#include <acpi/cppc_acpi.h>

static inline void topology_init_cpu_capacity_cppc(void)
{
	u64 capacity, capacity_scale = 0;
	struct cppc_perf_caps perf_caps;
	int cpu;

	if (likely(!acpi_cpc_valid()))
		return;

	raw_capacity = kcalloc(num_possible_cpus(), sizeof(*raw_capacity),
			       GFP_KERNEL);
	if (!raw_capacity)
		return;

	for_each_possible_cpu(cpu) {
		if (!cppc_get_perf_caps(cpu, &perf_caps) &&
		    (perf_caps.highest_perf >= perf_caps.nominal_perf) &&
		    (perf_caps.highest_perf >= perf_caps.lowest_perf)) {
			raw_capacity[cpu] = perf_caps.highest_perf;
			capacity_scale = max_t(u64, capacity_scale, raw_capacity[cpu]);

			per_cpu(capacity_freq_ref, cpu) = cppc_perf_to_khz(&perf_caps, raw_capacity[cpu]);

			pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n",
				 cpu, raw_capacity[cpu]);
			continue;
		}

		pr_err("cpu_capacity: CPU%d missing/invalid highest performance.\n", cpu);
		pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
		goto exit;
	}

	for_each_possible_cpu(cpu) {
		freq_inv_set_max_ratio(cpu,
				       per_cpu(capacity_freq_ref, cpu) * HZ_PER_KHZ);

		capacity = raw_capacity[cpu];
		capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
				     capacity_scale);
		topology_set_cpu_scale(cpu, capacity);
		pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
			cpu, topology_get_cpu_scale(cpu));
	}

	schedule_work(&update_topology_flags_work);
	pr_debug("cpu_capacity: cpu_capacity initialization done\n");

exit:
	free_raw_capacity();
}
void acpi_processor_init_invariance_cppc(void)
{
	topology_init_cpu_capacity_cppc();
}
#endif

#ifdef CONFIG_CPU_FREQ
static cpumask_var_t cpus_to_visit;
static void parsing_done_workfn(struct work_struct *work);
static DECLARE_WORK(parsing_done_work, parsing_done_workfn);

static int
init_cpu_capacity_callback(struct notifier_block *nb,
			   unsigned long val,
			   void *data)
{
	struct cpufreq_policy *policy = data;
	int cpu;

	if (val != CPUFREQ_CREATE_POLICY)
		return 0;

	pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
		 cpumask_pr_args(policy->related_cpus),
		 cpumask_pr_args(cpus_to_visit));

	cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);

	for_each_cpu(cpu, policy->related_cpus) {
		per_cpu(capacity_freq_ref, cpu) = policy->cpuinfo.max_freq;
		freq_inv_set_max_ratio(cpu,
				       per_cpu(capacity_freq_ref, cpu) * HZ_PER_KHZ);
	}

	if (cpumask_empty(cpus_to_visit)) {
		if (raw_capacity) {
			topology_normalize_cpu_scale();
			schedule_work(&update_topology_flags_work);
			free_raw_capacity();
		}
		pr_debug("cpu_capacity: parsing done\n");
		schedule_work(&parsing_done_work);
	}

	return 0;
}

static struct notifier_block init_cpu_capacity_notifier = {
	.notifier_call = init_cpu_capacity_callback,
};

static int __init register_cpufreq_notifier(void)
{
	int ret;

	/*
	 * On ACPI-based systems skip registering cpufreq notifier as cpufreq
	 * information is not needed for cpu capacity initialization.
	 */
	if (!acpi_disabled)
		return -EINVAL;

	if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL))
		return -ENOMEM;

	cpumask_copy(cpus_to_visit, cpu_possible_mask);

	ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
					CPUFREQ_POLICY_NOTIFIER);

	if (ret)
		free_cpumask_var(cpus_to_visit);

	return ret;
}
core_initcall(register_cpufreq_notifier);

static void parsing_done_workfn(struct work_struct *work)
{
	cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
					 CPUFREQ_POLICY_NOTIFIER);
	free_cpumask_var(cpus_to_visit);
}

#else
core_initcall(free_raw_capacity);
#endif

#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)

/* Used to enable the SMT control */
static unsigned int max_smt_thread_num = 1;

/*
 * This function returns the logic cpu number of the node.
 * There are basically three kinds of return values:
 * (1) logic cpu number which is > 0.
 * (2) -ENODEV when the device tree(DT) node is valid and found in the DT but
 * there is no possible logical CPU in the kernel to match. This happens
 * when CONFIG_NR_CPUS is configure to be smaller than the number of
 * CPU nodes in DT. We need to just ignore this case.
 * (3) -1 if the node does not exist in the device tree
 */
static int __init get_cpu_for_node(struct device_node *node)
{
	int cpu;
	struct device_node *cpu_node __free(device_node) =
		of_parse_phandle(node, "cpu", 0);

	if (!cpu_node)
		return -1;

	cpu = of_cpu_node_to_id(cpu_node);
	if (cpu >= 0)
		topology_parse_cpu_capacity(cpu_node, cpu);
	else
		pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n",
			cpu_node, cpumask_pr_args(cpu_possible_mask));

	return cpu;
}

static int __init parse_core(struct device_node *core, int package_id,
			     int cluster_id, int core_id)
{
	char name[20];
	bool leaf = true;
	int i = 0;
	int cpu;

	do {
		snprintf(name, sizeof(name), "thread%d", i);
		struct device_node *t __free(device_node) =
			of_get_child_by_name(core, name);

		if (!t)
			break;

		leaf = false;
		cpu = get_cpu_for_node(t);
		if (cpu >= 0) {
			cpu_topology[cpu].package_id = package_id;
			cpu_topology[cpu].cluster_id = cluster_id;
			cpu_topology[cpu].core_id = core_id;
			cpu_topology[cpu].thread_id = i;
		} else if (cpu != -ENODEV) {
			pr_err("%pOF: Can't get CPU for thread\n", t);
			return -EINVAL;
		}
		i++;
	} while (1);

	max_smt_thread_num = max_t(unsigned int, max_smt_thread_num, i);

	cpu = get_cpu_for_node(core);
	if (cpu >= 0) {
		if (!leaf) {
			pr_err("%pOF: Core has both threads and CPU\n",
			       core);
			return -EINVAL;
		}

		cpu_topology[cpu].package_id = package_id;
		cpu_topology[cpu].cluster_id = cluster_id;
		cpu_topology[cpu].core_id = core_id;
	} else if (leaf && cpu != -ENODEV) {
		pr_err("%pOF: Can't get CPU for leaf core\n", core);
		return -EINVAL;
	}

	return 0;
}

static int __init parse_cluster(struct device_node *cluster, int package_id,
				int cluster_id, int depth)
{
	char name[20];
	bool leaf = true;
	bool has_cores = false;
	int core_id = 0;
	int i, ret;

	/*
	 * First check for child clusters; we currently ignore any
	 * information about the nesting of clusters and present the
	 * scheduler with a flat list of them.
	 */
	i = 0;
	do {
		snprintf(name, sizeof(name), "cluster%d", i);
		struct device_node *c __free(device_node) =
			of_get_child_by_name(cluster, name);

		if (!c)
			break;

		leaf = false;
		ret = parse_cluster(c, package_id, i, depth + 1);
		if (depth > 0)
			pr_warn("Topology for clusters of clusters not yet supported\n");
		if (ret != 0)
			return ret;
		i++;
	} while (1);

	/* Now check for cores */
	i = 0;
	do {
		snprintf(name, sizeof(name), "core%d", i);
		struct device_node *c __free(device_node) =
			of_get_child_by_name(cluster, name);

		if (!c)
			break;

		has_cores = true;

		if (depth == 0) {
			pr_err("%pOF: cpu-map children should be clusters\n", c);
			return -EINVAL;
		}

		if (leaf) {
			ret = parse_core(c, package_id, cluster_id, core_id++);
			if (ret != 0)
				return ret;
		} else {
			pr_err("%pOF: Non-leaf cluster with core %s\n",
			       cluster, name);
			return -EINVAL;
		}

		i++;
	} while (1);

	if (leaf && !has_cores)
		pr_warn("%pOF: empty cluster\n", cluster);

	return 0;
}

static int __init parse_socket(struct device_node *socket)
{
	char name[20];
	bool has_socket = false;
	int package_id = 0, ret;

	do {
		snprintf(name, sizeof(name), "socket%d", package_id);
		struct device_node *c __free(device_node) =
			of_get_child_by_name(socket, name);

		if (!c)
			break;

		has_socket = true;
		ret = parse_cluster(c, package_id, -1, 0);
		if (ret != 0)
			return ret;

		package_id++;
	} while (1);

	if (!has_socket)
		ret = parse_cluster(socket, 0, -1, 0);

	/*
	 * Reset the max_smt_thread_num to 1 on failure. Since on failure
	 * we need to notify the framework the SMT is not supported, but
	 * max_smt_thread_num can be initialized to the SMT thread number
	 * of the cores which are successfully parsed.
	 */
	if (ret)
		max_smt_thread_num = 1;

	cpu_smt_set_num_threads(max_smt_thread_num, max_smt_thread_num);

	return ret;
}

static int __init parse_dt_topology(void)
{
	int ret = 0;
	int cpu;
	struct device_node *cn __free(device_node) =
		of_find_node_by_path("/cpus");

	if (!cn) {
		pr_err("No CPU information found in DT\n");
		return 0;
	}

	/*
	 * When topology is provided cpu-map is essentially a root
	 * cluster with restricted subnodes.
	 */
	struct device_node *map __free(device_node) =
		of_get_child_by_name(cn, "cpu-map");

	if (!map)
		return ret;

	ret = parse_socket(map);
	if (ret != 0)
		return ret;

	topology_normalize_cpu_scale();

	/*
	 * Check that all cores are in the topology; the SMP code will
	 * only mark cores described in the DT as possible.
	 */
	for_each_possible_cpu(cpu)
		if (cpu_topology[cpu].package_id < 0) {
			return -EINVAL;
		}

	return ret;
}
#endif

/*
 * cpu topology table
 */
struct cpu_topology cpu_topology[NR_CPUS];
EXPORT_SYMBOL_GPL(cpu_topology);

const struct cpumask *cpu_coregroup_mask(int cpu)
{
	const cpumask_t *core_mask = cpumask_of_node(cpu_to_node(cpu));

	/* Find the smaller of NUMA, core or LLC siblings */
	if (cpumask_subset(&cpu_topology[cpu].core_sibling, core_mask)) {
		/* not numa in package, lets use the package siblings */
		core_mask = &cpu_topology[cpu].core_sibling;
	}

	if (last_level_cache_is_valid(cpu)) {
		if (cpumask_subset(&cpu_topology[cpu].llc_sibling, core_mask))
			core_mask = &cpu_topology[cpu].llc_sibling;
	}

	/*
	 * For systems with no shared cpu-side LLC but with clusters defined,
	 * extend core_mask to cluster_siblings. The sched domain builder will
	 * then remove MC as redundant with CLS if SCHED_CLUSTER is enabled.
	 */
	if (IS_ENABLED(CONFIG_SCHED_CLUSTER) &&
	    cpumask_subset(core_mask, &cpu_topology[cpu].cluster_sibling))
		core_mask = &cpu_topology[cpu].cluster_sibling;

	return core_mask;
}

const struct cpumask *cpu_clustergroup_mask(int cpu)
{
	/*
	 * Forbid cpu_clustergroup_mask() to span more or the same CPUs as
	 * cpu_coregroup_mask().
	 */
	if (cpumask_subset(cpu_coregroup_mask(cpu),
			   &cpu_topology[cpu].cluster_sibling))
		return topology_sibling_cpumask(cpu);

	return &cpu_topology[cpu].cluster_sibling;
}

void update_siblings_masks(unsigned int cpuid)
{
	struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
	int cpu, ret;

	ret = detect_cache_attributes(cpuid);
	if (ret && ret != -ENOENT)
		pr_info("Early cacheinfo allocation failed, ret = %d\n", ret);

	/* update core and thread sibling masks */
	for_each_online_cpu(cpu) {
		cpu_topo = &cpu_topology[cpu];

		if (last_level_cache_is_shared(cpu, cpuid)) {
			cpumask_set_cpu(cpu, &cpuid_topo->llc_sibling);
			cpumask_set_cpu(cpuid, &cpu_topo->llc_sibling);
		}

		if (cpuid_topo->package_id != cpu_topo->package_id)
			continue;

		cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
		cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);

		if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
			continue;

		if (cpuid_topo->cluster_id >= 0) {
			cpumask_set_cpu(cpu, &cpuid_topo->cluster_sibling);
			cpumask_set_cpu(cpuid, &cpu_topo->cluster_sibling);
		}

		if (cpuid_topo->core_id != cpu_topo->core_id)
			continue;

		cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
		cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
	}
}

static void clear_cpu_topology(int cpu)
{
	struct cpu_topology *cpu_topo = &cpu_topology[cpu];

	cpumask_clear(&cpu_topo->llc_sibling);
	cpumask_set_cpu(cpu, &cpu_topo->llc_sibling);

	cpumask_clear(&cpu_topo->cluster_sibling);
	cpumask_set_cpu(cpu, &cpu_topo->cluster_sibling);

	cpumask_clear(&cpu_topo->core_sibling);
	cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
	cpumask_clear(&cpu_topo->thread_sibling);
	cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
}

void __init reset_cpu_topology(void)
{
	unsigned int cpu;

	for_each_possible_cpu(cpu) {
		struct cpu_topology *cpu_topo = &cpu_topology[cpu];

		cpu_topo->thread_id = -1;
		cpu_topo->core_id = -1;
		cpu_topo->cluster_id = -1;
		cpu_topo->package_id = -1;

		clear_cpu_topology(cpu);
	}
}

void remove_cpu_topology(unsigned int cpu)
{
	int sibling;

	for_each_cpu(sibling, topology_core_cpumask(cpu))
		cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
	for_each_cpu(sibling, topology_sibling_cpumask(cpu))
		cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
	for_each_cpu(sibling, topology_cluster_cpumask(cpu))
		cpumask_clear_cpu(cpu, topology_cluster_cpumask(sibling));
	for_each_cpu(sibling, topology_llc_cpumask(cpu))
		cpumask_clear_cpu(cpu, topology_llc_cpumask(sibling));

	clear_cpu_topology(cpu);
}

#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
struct cpu_smt_info {
	unsigned int thread_num;
	int core_id;
};

static bool __init acpi_cpu_is_threaded(int cpu)
{
	int is_threaded = acpi_pptt_cpu_is_thread(cpu);

	/*
	 * if the PPTT doesn't have thread information, check for architecture
	 * specific fallback if available
	 */
	if (is_threaded < 0)
		is_threaded = arch_cpu_is_threaded();

	return !!is_threaded;
}

/*
 * Propagate the topology information of the processor_topology_node tree to the
 * cpu_topology array.
 */
__weak int __init parse_acpi_topology(void)
{
	unsigned int max_smt_thread_num = 1;
	struct cpu_smt_info *entry;
	struct xarray hetero_cpu;
	unsigned long hetero_id;
	int cpu, topology_id;

	if (acpi_disabled)
		return 0;

	xa_init(&hetero_cpu);

	for_each_possible_cpu(cpu) {
		topology_id = find_acpi_cpu_topology(cpu, 0);
		if (topology_id < 0)
			return topology_id;

		if (acpi_cpu_is_threaded(cpu)) {
			cpu_topology[cpu].thread_id = topology_id;
			topology_id = find_acpi_cpu_topology(cpu, 1);
			cpu_topology[cpu].core_id   = topology_id;

			/*
			 * In the PPTT, CPUs below a node with the 'identical
			 * implementation' flag have the same number of threads.
			 * Count the number of threads for only one CPU (i.e.
			 * one core_id) among those with the same hetero_id.
			 * See the comment of find_acpi_cpu_topology_hetero_id()
			 * for more details.
			 *
			 * One entry is created for each node having:
			 * - the 'identical implementation' flag
			 * - its parent not having the flag
			 */
			hetero_id = find_acpi_cpu_topology_hetero_id(cpu);
			entry = xa_load(&hetero_cpu, hetero_id);
			if (!entry) {
				entry = kzalloc_obj(*entry);
				WARN_ON_ONCE(!entry);

				if (entry) {
					entry->core_id = topology_id;
					entry->thread_num = 1;
					xa_store(&hetero_cpu, hetero_id,
						 entry, GFP_KERNEL);
				}
			} else if (entry->core_id == topology_id) {
				entry->thread_num++;
			}
		} else {
			cpu_topology[cpu].thread_id  = -1;
			cpu_topology[cpu].core_id    = topology_id;
		}
		topology_id = find_acpi_cpu_topology_cluster(cpu);
		cpu_topology[cpu].cluster_id = topology_id;
		topology_id = find_acpi_cpu_topology_package(cpu);
		cpu_topology[cpu].package_id = topology_id;
	}

	/*
	 * This is a short loop since the number of XArray elements is the
	 * number of heterogeneous CPU clusters. On a homogeneous system
	 * there's only one entry in the XArray.
	 */
	xa_for_each(&hetero_cpu, hetero_id, entry) {
		max_smt_thread_num = max(max_smt_thread_num, entry->thread_num);
		xa_erase(&hetero_cpu, hetero_id);
		kfree(entry);
	}

	cpu_smt_set_num_threads(max_smt_thread_num, max_smt_thread_num);
	xa_destroy(&hetero_cpu);
	return 0;
}

void __init init_cpu_topology(void)
{
	int cpu, ret;

	reset_cpu_topology();
	ret = parse_acpi_topology();
	if (!ret)
		ret = of_have_populated_dt() && parse_dt_topology();

	if (ret) {
		/*
		 * Discard anything that was parsed if we hit an error so we
		 * don't use partial information. But do not return yet to give
		 * arch-specific early cache level detection a chance to run.
		 */
		reset_cpu_topology();
	}

	for_each_possible_cpu(cpu) {
		ret = fetch_cache_info(cpu);
		if (!ret)
			continue;
		else if (ret != -ENOENT)
			pr_err("Early cacheinfo failed, ret = %d\n", ret);
		return;
	}
}

void store_cpu_topology(unsigned int cpuid)
{
	struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];

	if (cpuid_topo->package_id != -1)
		goto topology_populated;

	cpuid_topo->thread_id = -1;
	cpuid_topo->core_id = cpuid;
	cpuid_topo->package_id = cpu_to_node(cpuid);

	pr_debug("CPU%u: package %d core %d thread %d\n",
		 cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
		 cpuid_topo->thread_id);

topology_populated:
	update_siblings_masks(cpuid);
}
#endif