// SPDX-License-Identifier: GPL-2.0
/*
 * cacheinfo support - processor cache information via sysfs
 *
 * Based on arch/x86/kernel/cpu/intel_cacheinfo.c
 * Author: Sudeep Holla <sudeep.holla@arm.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/cacheinfo.h>
#include <linux/compiler.h>
#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/sched.h>
#include <linux/sched/topology.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/sysfs.h>

/* pointer to per cpu cacheinfo */
static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
#define ci_cacheinfo(cpu)       (&per_cpu(ci_cpu_cacheinfo, cpu))
#define cache_leaves(cpu)       (ci_cacheinfo(cpu)->num_leaves)
#define per_cpu_cacheinfo(cpu)  (ci_cacheinfo(cpu)->info_list)
#define per_cpu_cacheinfo_idx(cpu, idx)         \
                                (per_cpu_cacheinfo(cpu) + (idx))

/* Set if no cache information is found in DT/ACPI. */
static bool use_arch_info;

struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
{
        return ci_cacheinfo(cpu);
}

static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
                                           struct cacheinfo *sib_leaf)
{
        /*
         * For non DT/ACPI systems, assume unique level 1 caches,
         * system-wide shared caches for all other levels.
         */
        if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)) ||
            use_arch_info)
                return (this_leaf->level != 1) && (sib_leaf->level != 1);

        if ((sib_leaf->attributes & CACHE_ID) &&
            (this_leaf->attributes & CACHE_ID))
                return sib_leaf->id == this_leaf->id;

        return sib_leaf->fw_token == this_leaf->fw_token;
}

bool last_level_cache_is_valid(unsigned int cpu)
{
        struct cacheinfo *llc;

        if (!cache_leaves(cpu) || !per_cpu_cacheinfo(cpu))
                return false;

        llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);

        return (llc->attributes & CACHE_ID) || !!llc->fw_token;

}

/*
 * Get the cacheinfo of the LLC associated with @cpu.
 * Derived from update_per_cpu_data_slice_size_cpu().
 */
struct cacheinfo *get_cpu_cacheinfo_llc(unsigned int cpu)
{
        struct cacheinfo *llc;

        if (!last_level_cache_is_valid(cpu))
                return NULL;

        llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
        if (llc->type != CACHE_TYPE_DATA && llc->type != CACHE_TYPE_UNIFIED)
                return NULL;

        return llc;
}

bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
{
        struct cacheinfo *llc_x, *llc_y;

        if (!last_level_cache_is_valid(cpu_x) ||
            !last_level_cache_is_valid(cpu_y))
                return false;

        llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1);
        llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1);

        return cache_leaves_are_shared(llc_x, llc_y);
}

#ifdef CONFIG_OF

static bool of_check_cache_nodes(struct device_node *np);

/* OF properties to query for a given cache type */
struct cache_type_info {
        const char *size_prop;
        const char *line_size_props[2];
        const char *nr_sets_prop;
};

static const struct cache_type_info cache_type_info[] = {
        {
                .size_prop       = "cache-size",
                .line_size_props = { "cache-line-size",
                                     "cache-block-size", },
                .nr_sets_prop    = "cache-sets",
        }, {
                .size_prop       = "i-cache-size",
                .line_size_props = { "i-cache-line-size",
                                     "i-cache-block-size", },
                .nr_sets_prop    = "i-cache-sets",
        }, {
                .size_prop       = "d-cache-size",
                .line_size_props = { "d-cache-line-size",
                                     "d-cache-block-size", },
                .nr_sets_prop    = "d-cache-sets",
        },
};

static inline int get_cacheinfo_idx(enum cache_type type)
{
        if (type == CACHE_TYPE_UNIFIED)
                return 0;
        return type;
}

static void cache_size(struct cacheinfo *this_leaf, struct device_node *np)
{
        const char *propname;
        int ct_idx;

        ct_idx = get_cacheinfo_idx(this_leaf->type);
        propname = cache_type_info[ct_idx].size_prop;

        of_property_read_u32(np, propname, &this_leaf->size);
}

/* not cache_line_size() because that's a macro in include/linux/cache.h */
static void cache_get_line_size(struct cacheinfo *this_leaf,
                                struct device_node *np)
{
        int i, lim, ct_idx;

        ct_idx = get_cacheinfo_idx(this_leaf->type);
        lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);

        for (i = 0; i < lim; i++) {
                int ret;
                u32 line_size;
                const char *propname;

                propname = cache_type_info[ct_idx].line_size_props[i];
                ret = of_property_read_u32(np, propname, &line_size);
                if (!ret) {
                        this_leaf->coherency_line_size = line_size;
                        break;
                }
        }
}

static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
{
        const char *propname;
        int ct_idx;

        ct_idx = get_cacheinfo_idx(this_leaf->type);
        propname = cache_type_info[ct_idx].nr_sets_prop;

        of_property_read_u32(np, propname, &this_leaf->number_of_sets);
}

static void cache_associativity(struct cacheinfo *this_leaf)
{
        unsigned int line_size = this_leaf->coherency_line_size;
        unsigned int nr_sets = this_leaf->number_of_sets;
        unsigned int size = this_leaf->size;

        /*
         * If the cache is fully associative, there is no need to
         * check the other properties.
         */
        if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
                this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
}

static bool cache_node_is_unified(struct cacheinfo *this_leaf,
                                  struct device_node *np)
{
        return of_property_read_bool(np, "cache-unified");
}

static bool match_cache_node(struct device_node *cpu,
                             const struct device_node *cache_node)
{
        struct device_node *prev, *cache = of_find_next_cache_node(cpu);

        while (cache) {
                if (cache == cache_node) {
                        of_node_put(cache);
                        return true;
                }

                prev = cache;
                cache = of_find_next_cache_node(cache);
                of_node_put(prev);
        }

        return false;
}

#ifndef arch_compact_of_hwid
#define arch_compact_of_hwid(_x)        (_x)
#endif

static void cache_of_set_id(struct cacheinfo *this_leaf,
                            struct device_node *cache_node)
{
        struct device_node *cpu;
        u32 min_id = ~0;

        for_each_of_cpu_node(cpu) {
                u64 id = of_get_cpu_hwid(cpu, 0);

                id = arch_compact_of_hwid(id);
                if (FIELD_GET(GENMASK_ULL(63, 32), id)) {
                        of_node_put(cpu);
                        return;
                }

                if (match_cache_node(cpu, cache_node))
                        min_id = min(min_id, id);
        }

        if (min_id != ~0) {
                this_leaf->id = min_id;
                this_leaf->attributes |= CACHE_ID;
        }
}

static void cache_of_set_props(struct cacheinfo *this_leaf,
                               struct device_node *np)
{
        /*
         * init_cache_level must setup the cache level correctly
         * overriding the architecturally specified levels, so
         * if type is NONE at this stage, it should be unified
         */
        if (this_leaf->type == CACHE_TYPE_NOCACHE &&
            cache_node_is_unified(this_leaf, np))
                this_leaf->type = CACHE_TYPE_UNIFIED;
        cache_size(this_leaf, np);
        cache_get_line_size(this_leaf, np);
        cache_nr_sets(this_leaf, np);
        cache_associativity(this_leaf);
        cache_of_set_id(this_leaf, np);
}

static int cache_setup_of_node(unsigned int cpu)
{
        struct cacheinfo *this_leaf;
        unsigned int index = 0;

        struct device_node *np __free(device_node) = of_cpu_device_node_get(cpu);
        if (!np) {
                pr_err("Failed to find cpu%d device node\n", cpu);
                return -ENOENT;
        }

        if (!of_check_cache_nodes(np)) {
                return -ENOENT;
        }

        while (index < cache_leaves(cpu)) {
                this_leaf = per_cpu_cacheinfo_idx(cpu, index);
                if (this_leaf->level != 1) {
                        struct device_node *prev __free(device_node) = np;
                        np = of_find_next_cache_node(np);
                        if (!np)
                                break;
                }
                cache_of_set_props(this_leaf, np);
                this_leaf->fw_token = np;
                index++;
        }

        if (index != cache_leaves(cpu)) /* not all OF nodes populated */
                return -ENOENT;

        return 0;
}

static bool of_check_cache_nodes(struct device_node *np)
{
        if (of_property_present(np, "cache-size")   ||
            of_property_present(np, "i-cache-size") ||
            of_property_present(np, "d-cache-size") ||
            of_property_present(np, "cache-unified"))
                return true;

        struct device_node *next __free(device_node) = of_find_next_cache_node(np);
        if (next) {
                return true;
        }

        return false;
}

static int of_count_cache_leaves(struct device_node *np)
{
        unsigned int leaves = 0;

        if (of_property_present(np, "cache-size"))
                ++leaves;
        if (of_property_present(np, "i-cache-size"))
                ++leaves;
        if (of_property_present(np, "d-cache-size"))
                ++leaves;

        if (!leaves) {
                /* The '[i-|d-|]cache-size' property is required, but
                 * if absent, fallback on the 'cache-unified' property.
                 */
                if (of_property_read_bool(np, "cache-unified"))
                        return 1;
                else
                        return 2;
        }

        return leaves;
}

int init_of_cache_level(unsigned int cpu)
{
        struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
        struct device_node *np __free(device_node) = of_cpu_device_node_get(cpu);
        unsigned int levels = 0, leaves, level;

        if (!of_check_cache_nodes(np)) {
                return -ENOENT;
        }

        leaves = of_count_cache_leaves(np);
        if (leaves > 0)
                levels = 1;

        while (1) {
                struct device_node *prev __free(device_node) = np;
                np = of_find_next_cache_node(np);
                if (!np)
                        break;

                if (!of_device_is_compatible(np, "cache"))
                        return -EINVAL;
                if (of_property_read_u32(np, "cache-level", &level))
                        return -EINVAL;
                if (level <= levels)
                        return -EINVAL;

                leaves += of_count_cache_leaves(np);
                levels = level;
        }

        this_cpu_ci->num_levels = levels;
        this_cpu_ci->num_leaves = leaves;

        return 0;
}

#else
static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
int init_of_cache_level(unsigned int cpu) { return 0; }
#endif

int __weak cache_setup_acpi(unsigned int cpu)
{
        return -ENOTSUPP;
}

unsigned int coherency_max_size;

static int cache_setup_properties(unsigned int cpu)
{
        int ret = 0;

        if (of_have_populated_dt())
                ret = cache_setup_of_node(cpu);
        else if (!acpi_disabled)
                ret = cache_setup_acpi(cpu);

        // Assume there is no cache information available in DT/ACPI from now.
        if (ret && use_arch_cache_info())
                use_arch_info = true;

        return ret;
}

static int cache_shared_cpu_map_setup(unsigned int cpu)
{
        struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
        struct cacheinfo *this_leaf, *sib_leaf;
        unsigned int index, sib_index;
        int ret = 0;

        if (this_cpu_ci->cpu_map_populated)
                return 0;

        /*
         * skip setting up cache properties if LLC is valid, just need
         * to update the shared cpu_map if the cache attributes were
         * populated early before all the cpus are brought online
         */
        if (!last_level_cache_is_valid(cpu) && !use_arch_info) {
                ret = cache_setup_properties(cpu);
                if (ret)
                        return ret;
        }

        for (index = 0; index < cache_leaves(cpu); index++) {
                unsigned int i;

                this_leaf = per_cpu_cacheinfo_idx(cpu, index);

                cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
                for_each_online_cpu(i) {
                        if (i == cpu || !per_cpu_cacheinfo(i))
                                continue;/* skip if itself or no cacheinfo */
                        for (sib_index = 0; sib_index < cache_leaves(i); sib_index++) {
                                sib_leaf = per_cpu_cacheinfo_idx(i, sib_index);

                                /*
                                 * Comparing cache IDs only makes sense if the leaves
                                 * belong to the same cache level of same type. Skip
                                 * the check if level and type do not match.
                                 */
                                if (sib_leaf->level != this_leaf->level ||
                                    sib_leaf->type != this_leaf->type)
                                        continue;

                                if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
                                        cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
                                        cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
                                        break;
                                }
                        }
                }
                /* record the maximum cache line size */
                if (this_leaf->coherency_line_size > coherency_max_size)
                        coherency_max_size = this_leaf->coherency_line_size;
        }

        /* shared_cpu_map is now populated for the cpu */
        this_cpu_ci->cpu_map_populated = true;
        return 0;
}

static void cache_shared_cpu_map_remove(unsigned int cpu)
{
        struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
        struct cacheinfo *this_leaf, *sib_leaf;
        unsigned int sibling, index, sib_index;

        for (index = 0; index < cache_leaves(cpu); index++) {
                this_leaf = per_cpu_cacheinfo_idx(cpu, index);
                for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
                        if (sibling == cpu || !per_cpu_cacheinfo(sibling))
                                continue;/* skip if itself or no cacheinfo */

                        for (sib_index = 0; sib_index < cache_leaves(sibling); sib_index++) {
                                sib_leaf = per_cpu_cacheinfo_idx(sibling, sib_index);

                                /*
                                 * Comparing cache IDs only makes sense if the leaves
                                 * belong to the same cache level of same type. Skip
                                 * the check if level and type do not match.
                                 */
                                if (sib_leaf->level != this_leaf->level ||
                                    sib_leaf->type != this_leaf->type)
                                        continue;

                                if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
                                        cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
                                        cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
                                        break;
                                }
                        }
                }
        }

        /* cpu is no longer populated in the shared map */
        this_cpu_ci->cpu_map_populated = false;
}

static void free_cache_attributes(unsigned int cpu)
{
        if (!per_cpu_cacheinfo(cpu))
                return;

        cache_shared_cpu_map_remove(cpu);
}

int __weak early_cache_level(unsigned int cpu)
{
        return -ENOENT;
}

int __weak init_cache_level(unsigned int cpu)
{
        return -ENOENT;
}

int __weak populate_cache_leaves(unsigned int cpu)
{
        return -ENOENT;
}

static inline int allocate_cache_info(int cpu)
{
        per_cpu_cacheinfo(cpu) = kzalloc_objs(struct cacheinfo,
                                              cache_leaves(cpu), GFP_ATOMIC);
        if (!per_cpu_cacheinfo(cpu)) {
                cache_leaves(cpu) = 0;
                return -ENOMEM;
        }

        return 0;
}

int fetch_cache_info(unsigned int cpu)
{
        struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
        unsigned int levels = 0, split_levels = 0;
        int ret;

        if (acpi_disabled) {
                ret = init_of_cache_level(cpu);
        } else {
                ret = acpi_get_cache_info(cpu, &levels, &split_levels);
                if (!ret) {
                        this_cpu_ci->num_levels = levels;
                        /*
                         * This assumes that:
                         * - there cannot be any split caches (data/instruction)
                         *   above a unified cache
                         * - data/instruction caches come by pair
                         */
                        this_cpu_ci->num_leaves = levels + split_levels;
                }
        }

        if (ret || !cache_leaves(cpu)) {
                ret = early_cache_level(cpu);
                if (ret)
                        return ret;

                if (!cache_leaves(cpu))
                        return -ENOENT;

                this_cpu_ci->early_ci_levels = true;
        }

        return allocate_cache_info(cpu);
}

static inline int init_level_allocate_ci(unsigned int cpu)
{
        unsigned int early_leaves = cache_leaves(cpu);

        /* Since early initialization/allocation of the cacheinfo is allowed
         * via fetch_cache_info() and this also gets called as CPU hotplug
         * callbacks via cacheinfo_cpu_online, the init/alloc can be skipped
         * as it will happen only once (the cacheinfo memory is never freed).
         * Just populate the cacheinfo. However, if the cacheinfo has been
         * allocated early through the arch-specific early_cache_level() call,
         * there is a chance the info is wrong (this can happen on arm64). In
         * that case, call init_cache_level() anyway to give the arch-specific
         * code a chance to make things right.
         */
        if (per_cpu_cacheinfo(cpu) && !ci_cacheinfo(cpu)->early_ci_levels)
                return 0;

        if (init_cache_level(cpu) || !cache_leaves(cpu))
                return -ENOENT;

        /*
         * Now that we have properly initialized the cache level info, make
         * sure we don't try to do that again the next time we are called
         * (e.g. as CPU hotplug callbacks).
         */
        ci_cacheinfo(cpu)->early_ci_levels = false;

        /*
         * Some architectures (e.g., x86) do not use early initialization.
         * Allocate memory now in such case.
         */
        if (cache_leaves(cpu) <= early_leaves && per_cpu_cacheinfo(cpu))
                return 0;

        kfree(per_cpu_cacheinfo(cpu));
        return allocate_cache_info(cpu);
}

int detect_cache_attributes(unsigned int cpu)
{
        int ret;

        ret = init_level_allocate_ci(cpu);
        if (ret)
                return ret;

        /*
         * If LLC is valid the cache leaves were already populated so just go to
         * update the cpu map.
         */
        if (!last_level_cache_is_valid(cpu)) {
                /*
                 * populate_cache_leaves() may completely setup the cache leaves and
                 * shared_cpu_map or it may leave it partially setup.
                 */
                ret = populate_cache_leaves(cpu);
                if (ret)
                        goto free_ci;
        }

        /*
         * For systems using DT for cache hierarchy, fw_token
         * and shared_cpu_map will be set up here only if they are
         * not populated already
         */
        ret = cache_shared_cpu_map_setup(cpu);
        if (ret) {
                pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
                goto free_ci;
        }

        return 0;

free_ci:
        free_cache_attributes(cpu);
        return ret;
}

/* pointer to cpuX/cache device */
static DEFINE_PER_CPU(struct device *, ci_cache_dev);
#define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))

static cpumask_t cache_dev_map;

/* pointer to array of devices for cpuX/cache/indexY */
static DEFINE_PER_CPU(struct device **, ci_index_dev);
#define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
#define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])

#define show_one(file_name, object)                             \
static ssize_t file_name##_show(struct device *dev,             \
                struct device_attribute *attr, char *buf)       \
{                                                               \
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
        return sysfs_emit(buf, "%u\n", this_leaf->object);      \
}

show_one(id, id);
show_one(level, level);
show_one(coherency_line_size, coherency_line_size);
show_one(number_of_sets, number_of_sets);
show_one(physical_line_partition, physical_line_partition);
show_one(ways_of_associativity, ways_of_associativity);

static ssize_t size_show(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);

        return sysfs_emit(buf, "%uK\n", this_leaf->size >> 10);
}

static ssize_t shared_cpu_map_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);
        const struct cpumask *mask = &this_leaf->shared_cpu_map;

        return sysfs_emit(buf, "%*pb\n", nr_cpu_ids, mask);
}

static ssize_t shared_cpu_list_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);
        const struct cpumask *mask = &this_leaf->shared_cpu_map;

        return sysfs_emit(buf, "%*pbl\n", nr_cpu_ids, mask);
}

static ssize_t type_show(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);
        const char *output;

        switch (this_leaf->type) {
        case CACHE_TYPE_DATA:
                output = "Data";
                break;
        case CACHE_TYPE_INST:
                output = "Instruction";
                break;
        case CACHE_TYPE_UNIFIED:
                output = "Unified";
                break;
        default:
                return -EINVAL;
        }

        return sysfs_emit(buf, "%s\n", output);
}

static ssize_t allocation_policy_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
{
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);
        unsigned int ci_attr = this_leaf->attributes;
        const char *output;

        if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
                output = "ReadWriteAllocate";
        else if (ci_attr & CACHE_READ_ALLOCATE)
                output = "ReadAllocate";
        else if (ci_attr & CACHE_WRITE_ALLOCATE)
                output = "WriteAllocate";
        else
                return 0;

        return sysfs_emit(buf, "%s\n", output);
}

static ssize_t write_policy_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);
        unsigned int ci_attr = this_leaf->attributes;
        int n = 0;

        if (ci_attr & CACHE_WRITE_THROUGH)
                n = sysfs_emit(buf, "WriteThrough\n");
        else if (ci_attr & CACHE_WRITE_BACK)
                n = sysfs_emit(buf, "WriteBack\n");
        return n;
}

static DEVICE_ATTR_RO(id);
static DEVICE_ATTR_RO(level);
static DEVICE_ATTR_RO(type);
static DEVICE_ATTR_RO(coherency_line_size);
static DEVICE_ATTR_RO(ways_of_associativity);
static DEVICE_ATTR_RO(number_of_sets);
static DEVICE_ATTR_RO(size);
static DEVICE_ATTR_RO(allocation_policy);
static DEVICE_ATTR_RO(write_policy);
static DEVICE_ATTR_RO(shared_cpu_map);
static DEVICE_ATTR_RO(shared_cpu_list);
static DEVICE_ATTR_RO(physical_line_partition);

static struct attribute *cache_default_attrs[] = {
        &dev_attr_id.attr,
        &dev_attr_type.attr,
        &dev_attr_level.attr,
        &dev_attr_shared_cpu_map.attr,
        &dev_attr_shared_cpu_list.attr,
        &dev_attr_coherency_line_size.attr,
        &dev_attr_ways_of_associativity.attr,
        &dev_attr_number_of_sets.attr,
        &dev_attr_size.attr,
        &dev_attr_allocation_policy.attr,
        &dev_attr_write_policy.attr,
        &dev_attr_physical_line_partition.attr,
        NULL
};

static umode_t
cache_default_attrs_is_visible(struct kobject *kobj,
                               struct attribute *attr, int unused)
{
        struct device *dev = kobj_to_dev(kobj);
        struct cacheinfo *this_leaf = dev_get_drvdata(dev);
        const struct cpumask *mask = &this_leaf->shared_cpu_map;
        umode_t mode = attr->mode;

        if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
                return mode;
        if ((attr == &dev_attr_type.attr) && this_leaf->type)
                return mode;
        if ((attr == &dev_attr_level.attr) && this_leaf->level)
                return mode;
        if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
                return mode;
        if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
                return mode;
        if ((attr == &dev_attr_coherency_line_size.attr) &&
            this_leaf->coherency_line_size)
                return mode;
        if ((attr == &dev_attr_ways_of_associativity.attr) &&
            this_leaf->size) /* allow 0 = full associativity */
                return mode;
        if ((attr == &dev_attr_number_of_sets.attr) &&
            this_leaf->number_of_sets)
                return mode;
        if ((attr == &dev_attr_size.attr) && this_leaf->size)
                return mode;
        if ((attr == &dev_attr_write_policy.attr) &&
            (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
                return mode;
        if ((attr == &dev_attr_allocation_policy.attr) &&
            (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
                return mode;
        if ((attr == &dev_attr_physical_line_partition.attr) &&
            this_leaf->physical_line_partition)
                return mode;

        return 0;
}

static const struct attribute_group cache_default_group = {
        .attrs = cache_default_attrs,
        .is_visible = cache_default_attrs_is_visible,
};

static const struct attribute_group *cache_default_groups[] = {
        &cache_default_group,
        NULL,
};

static const struct attribute_group *cache_private_groups[] = {
        &cache_default_group,
        NULL, /* Place holder for private group */
        NULL,
};

const struct attribute_group *
__weak cache_get_priv_group(struct cacheinfo *this_leaf)
{
        return NULL;
}

static const struct attribute_group **
cache_get_attribute_groups(struct cacheinfo *this_leaf)
{
        const struct attribute_group *priv_group =
                        cache_get_priv_group(this_leaf);

        if (!priv_group)
                return cache_default_groups;

        if (!cache_private_groups[1])
                cache_private_groups[1] = priv_group;

        return cache_private_groups;
}

/* Add/Remove cache interface for CPU device */
static void cpu_cache_sysfs_exit(unsigned int cpu)
{
        int i;
        struct device *ci_dev;

        if (per_cpu_index_dev(cpu)) {
                for (i = 0; i < cache_leaves(cpu); i++) {
                        ci_dev = per_cache_index_dev(cpu, i);
                        if (!ci_dev)
                                continue;
                        device_unregister(ci_dev);
                }
                kfree(per_cpu_index_dev(cpu));
                per_cpu_index_dev(cpu) = NULL;
        }
        device_unregister(per_cpu_cache_dev(cpu));
        per_cpu_cache_dev(cpu) = NULL;
}

static int cpu_cache_sysfs_init(unsigned int cpu)
{
        struct device *dev = get_cpu_device(cpu);

        if (per_cpu_cacheinfo(cpu) == NULL)
                return -ENOENT;

        per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
        if (IS_ERR(per_cpu_cache_dev(cpu)))
                return PTR_ERR(per_cpu_cache_dev(cpu));

        /* Allocate all required memory */
        per_cpu_index_dev(cpu) = kzalloc_objs(struct device *,
                                              cache_leaves(cpu));
        if (unlikely(per_cpu_index_dev(cpu) == NULL))
                goto err_out;

        return 0;

err_out:
        cpu_cache_sysfs_exit(cpu);
        return -ENOMEM;
}

static int cache_add_dev(unsigned int cpu)
{
        unsigned int i;
        int rc;
        struct device *ci_dev, *parent;
        struct cacheinfo *this_leaf;
        const struct attribute_group **cache_groups;

        rc = cpu_cache_sysfs_init(cpu);
        if (unlikely(rc < 0))
                return rc;

        parent = per_cpu_cache_dev(cpu);
        for (i = 0; i < cache_leaves(cpu); i++) {
                this_leaf = per_cpu_cacheinfo_idx(cpu, i);
                if (this_leaf->disable_sysfs)
                        continue;
                if (this_leaf->type == CACHE_TYPE_NOCACHE)
                        break;
                cache_groups = cache_get_attribute_groups(this_leaf);
                ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
                                           "index%1u", i);
                if (IS_ERR(ci_dev)) {
                        rc = PTR_ERR(ci_dev);
                        goto err;
                }
                per_cache_index_dev(cpu, i) = ci_dev;
        }
        cpumask_set_cpu(cpu, &cache_dev_map);

        return 0;
err:
        cpu_cache_sysfs_exit(cpu);
        return rc;
}

static unsigned int cpu_map_shared_cache(bool online, unsigned int cpu,
                                         cpumask_t **map)
{
        struct cacheinfo *llc, *sib_llc;
        unsigned int sibling;

        if (!last_level_cache_is_valid(cpu))
                return 0;

        llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);

        if (llc->type != CACHE_TYPE_DATA && llc->type != CACHE_TYPE_UNIFIED)
                return 0;

        if (online) {
                *map = &llc->shared_cpu_map;
                return cpumask_weight(*map);
        }

        /* shared_cpu_map of offlined CPU will be cleared, so use sibling map */
        for_each_cpu(sibling, &llc->shared_cpu_map) {
                if (sibling == cpu || !last_level_cache_is_valid(sibling))
                        continue;
                sib_llc = per_cpu_cacheinfo_idx(sibling, cache_leaves(sibling) - 1);
                *map = &sib_llc->shared_cpu_map;
                return cpumask_weight(*map);
        }

        return 0;
}

/*
 * Calculate the size of the per-CPU data cache slice.  This can be
 * used to estimate the size of the data cache slice that can be used
 * by one CPU under ideal circumstances.  UNIFIED caches are counted
 * in addition to DATA caches.  So, please consider code cache usage
 * when use the result.
 *
 * Because the cache inclusive/non-inclusive information isn't
 * available, we just use the size of the per-CPU slice of LLC to make
 * the result more predictable across architectures.
 */
static void update_per_cpu_data_slice_size_cpu(unsigned int cpu)
{
        struct cpu_cacheinfo *ci;
        struct cacheinfo *llc;
        unsigned int nr_shared;

        if (!last_level_cache_is_valid(cpu))
                return;

        ci = ci_cacheinfo(cpu);
        llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);

        if (llc->type != CACHE_TYPE_DATA && llc->type != CACHE_TYPE_UNIFIED)
                return;

        nr_shared = cpumask_weight(&llc->shared_cpu_map);
        if (nr_shared)
                ci->per_cpu_data_slice_size = llc->size / nr_shared;
}

static void update_per_cpu_data_slice_size(bool cpu_online, unsigned int cpu,
                                           cpumask_t *cpu_map)
{
        unsigned int icpu;

        for_each_cpu(icpu, cpu_map) {
                if (!cpu_online && icpu == cpu)
                        continue;
                update_per_cpu_data_slice_size_cpu(icpu);
                setup_pcp_cacheinfo(icpu);
        }
}

static int cacheinfo_cpu_online(unsigned int cpu)
{
        int rc = detect_cache_attributes(cpu);
        cpumask_t *cpu_map;

        if (rc)
                return rc;
        rc = cache_add_dev(cpu);
        if (rc)
                goto err;
        if (cpu_map_shared_cache(true, cpu, &cpu_map))
                update_per_cpu_data_slice_size(true, cpu, cpu_map);
        sched_update_llc_bytes(cpu);
        return 0;
err:
        free_cache_attributes(cpu);
        return rc;
}

static int cacheinfo_cpu_pre_down(unsigned int cpu)
{
        cpumask_t *cpu_map;
        unsigned int nr_shared;

        nr_shared = cpu_map_shared_cache(false, cpu, &cpu_map);
        if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
                cpu_cache_sysfs_exit(cpu);

        free_cache_attributes(cpu);
        if (nr_shared > 1)
                update_per_cpu_data_slice_size(false, cpu, cpu_map);

        sched_update_llc_bytes(cpu);

        return 0;
}

static int __init cacheinfo_sysfs_init(void)
{
        return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE,
                                 "base/cacheinfo:online",
                                 cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
}
device_initcall(cacheinfo_sysfs_init);