drivers/base/cacheinfo.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * cacheinfo support - processor cache information via sysfs
0004  *
0005  * Based on arch/x86/kernel/cpu/intel_cacheinfo.c
0006  * Author: Sudeep Holla <sudeep.holla@arm.com>
0007  */
0008 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0009
0010 #include <linux/acpi.h>
0011 #include <linux/bitops.h>
0012 #include <linux/cacheinfo.h>
0013 #include <linux/compiler.h>
0014 #include <linux/cpu.h>
0015 #include <linux/device.h>
0016 #include <linux/init.h>
0017 #include <linux/of_device.h>
0018 #include <linux/sched.h>
0019 #include <linux/slab.h>
0020 #include <linux/smp.h>
0021 #include <linux/sysfs.h>
0022
0023 /* pointer to per cpu cacheinfo */
0024 static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
0025 #define ci_cacheinfo(cpu)   (&per_cpu(ci_cpu_cacheinfo, cpu))
0026 #define cache_leaves(cpu)   (ci_cacheinfo(cpu)->num_leaves)
0027 #define per_cpu_cacheinfo(cpu)  (ci_cacheinfo(cpu)->info_list)
0028 #define per_cpu_cacheinfo_idx(cpu, idx)     \
0029                 (per_cpu_cacheinfo(cpu) + (idx))
0030
0031 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
0032 {
0033     return ci_cacheinfo(cpu);
0034 }
0035
0036 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
0037                        struct cacheinfo *sib_leaf)
0038 {
0039     /*
0040      * For non DT/ACPI systems, assume unique level 1 caches,
0041      * system-wide shared caches for all other levels. This will be used
0042      * only if arch specific code has not populated shared_cpu_map
0043      */
0044     if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)))
0045         return !(this_leaf->level == 1);
0046
0047     if ((sib_leaf->attributes & CACHE_ID) &&
0048         (this_leaf->attributes & CACHE_ID))
0049         return sib_leaf->id == this_leaf->id;
0050
0051     return sib_leaf->fw_token == this_leaf->fw_token;
0052 }
0053
0054 bool last_level_cache_is_valid(unsigned int cpu)
0055 {
0056     struct cacheinfo *llc;
0057
0058     if (!cache_leaves(cpu))
0059         return false;
0060
0061     llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
0062
0063     return (llc->attributes & CACHE_ID) || !!llc->fw_token;
0064
0065 }
0066
0067 bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
0068 {
0069     struct cacheinfo *llc_x, *llc_y;
0070
0071     if (!last_level_cache_is_valid(cpu_x) ||
0072         !last_level_cache_is_valid(cpu_y))
0073         return false;
0074
0075     llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1);
0076     llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1);
0077
0078     return cache_leaves_are_shared(llc_x, llc_y);
0079 }
0080
0081 #ifdef CONFIG_OF
0082 /* OF properties to query for a given cache type */
0083 struct cache_type_info {
0084     const char *size_prop;
0085     const char *line_size_props[2];
0086     const char *nr_sets_prop;
0087 };
0088
0089 static const struct cache_type_info cache_type_info[] = {
0090     {
0091         .size_prop       = "cache-size",
0092         .line_size_props = { "cache-line-size",
0093                      "cache-block-size", },
0094         .nr_sets_prop    = "cache-sets",
0095     }, {
0096         .size_prop       = "i-cache-size",
0097         .line_size_props = { "i-cache-line-size",
0098                      "i-cache-block-size", },
0099         .nr_sets_prop    = "i-cache-sets",
0100     }, {
0101         .size_prop       = "d-cache-size",
0102         .line_size_props = { "d-cache-line-size",
0103                      "d-cache-block-size", },
0104         .nr_sets_prop    = "d-cache-sets",
0105     },
0106 };
0107
0108 static inline int get_cacheinfo_idx(enum cache_type type)
0109 {
0110     if (type == CACHE_TYPE_UNIFIED)
0111         return 0;
0112     return type;
0113 }
0114
0115 static void cache_size(struct cacheinfo *this_leaf, struct device_node *np)
0116 {
0117     const char *propname;
0118     int ct_idx;
0119
0120     ct_idx = get_cacheinfo_idx(this_leaf->type);
0121     propname = cache_type_info[ct_idx].size_prop;
0122
0123     of_property_read_u32(np, propname, &this_leaf->size);
0124 }
0125
0126 /* not cache_line_size() because that's a macro in include/linux/cache.h */
0127 static void cache_get_line_size(struct cacheinfo *this_leaf,
0128                 struct device_node *np)
0129 {
0130     int i, lim, ct_idx;
0131
0132     ct_idx = get_cacheinfo_idx(this_leaf->type);
0133     lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
0134
0135     for (i = 0; i < lim; i++) {
0136         int ret;
0137         u32 line_size;
0138         const char *propname;
0139
0140         propname = cache_type_info[ct_idx].line_size_props[i];
0141         ret = of_property_read_u32(np, propname, &line_size);
0142         if (!ret) {
0143             this_leaf->coherency_line_size = line_size;
0144             break;
0145         }
0146     }
0147 }
0148
0149 static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
0150 {
0151     const char *propname;
0152     int ct_idx;
0153
0154     ct_idx = get_cacheinfo_idx(this_leaf->type);
0155     propname = cache_type_info[ct_idx].nr_sets_prop;
0156
0157     of_property_read_u32(np, propname, &this_leaf->number_of_sets);
0158 }
0159
0160 static void cache_associativity(struct cacheinfo *this_leaf)
0161 {
0162     unsigned int line_size = this_leaf->coherency_line_size;
0163     unsigned int nr_sets = this_leaf->number_of_sets;
0164     unsigned int size = this_leaf->size;
0165
0166     /*
0167      * If the cache is fully associative, there is no need to
0168      * check the other properties.
0169      */
0170     if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
0171         this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
0172 }
0173
0174 static bool cache_node_is_unified(struct cacheinfo *this_leaf,
0175                   struct device_node *np)
0176 {
0177     return of_property_read_bool(np, "cache-unified");
0178 }
0179
0180 static void cache_of_set_props(struct cacheinfo *this_leaf,
0181                    struct device_node *np)
0182 {
0183     /*
0184      * init_cache_level must setup the cache level correctly
0185      * overriding the architecturally specified levels, so
0186      * if type is NONE at this stage, it should be unified
0187      */
0188     if (this_leaf->type == CACHE_TYPE_NOCACHE &&
0189         cache_node_is_unified(this_leaf, np))
0190         this_leaf->type = CACHE_TYPE_UNIFIED;
0191     cache_size(this_leaf, np);
0192     cache_get_line_size(this_leaf, np);
0193     cache_nr_sets(this_leaf, np);
0194     cache_associativity(this_leaf);
0195 }
0196
0197 static int cache_setup_of_node(unsigned int cpu)
0198 {
0199     struct device_node *np;
0200     struct cacheinfo *this_leaf;
0201     unsigned int index = 0;
0202
0203     np = of_cpu_device_node_get(cpu);
0204     if (!np) {
0205         pr_err("Failed to find cpu%d device node\n", cpu);
0206         return -ENOENT;
0207     }
0208
0209     while (index < cache_leaves(cpu)) {
0210         this_leaf = per_cpu_cacheinfo_idx(cpu, index);
0211         if (this_leaf->level != 1)
0212             np = of_find_next_cache_node(np);
0213         else
0214             np = of_node_get(np);/* cpu node itself */
0215         if (!np)
0216             break;
0217         cache_of_set_props(this_leaf, np);
0218         this_leaf->fw_token = np;
0219         index++;
0220     }
0221
0222     if (index != cache_leaves(cpu)) /* not all OF nodes populated */
0223         return -ENOENT;
0224
0225     return 0;
0226 }
0227 #else
0228 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
0229 #endif
0230
0231 int __weak cache_setup_acpi(unsigned int cpu)
0232 {
0233     return -ENOTSUPP;
0234 }
0235
0236 unsigned int coherency_max_size;
0237
0238 static int cache_setup_properties(unsigned int cpu)
0239 {
0240     int ret = 0;
0241
0242     if (of_have_populated_dt())
0243         ret = cache_setup_of_node(cpu);
0244     else if (!acpi_disabled)
0245         ret = cache_setup_acpi(cpu);
0246
0247     return ret;
0248 }
0249
0250 static int cache_shared_cpu_map_setup(unsigned int cpu)
0251 {
0252     struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
0253     struct cacheinfo *this_leaf, *sib_leaf;
0254     unsigned int index;
0255     int ret = 0;
0256
0257     if (this_cpu_ci->cpu_map_populated)
0258         return 0;
0259
0260     /*
0261      * skip setting up cache properties if LLC is valid, just need
0262      * to update the shared cpu_map if the cache attributes were
0263      * populated early before all the cpus are brought online
0264      */
0265     if (!last_level_cache_is_valid(cpu)) {
0266         ret = cache_setup_properties(cpu);
0267         if (ret)
0268             return ret;
0269     }
0270
0271     for (index = 0; index < cache_leaves(cpu); index++) {
0272         unsigned int i;
0273
0274         this_leaf = per_cpu_cacheinfo_idx(cpu, index);
0275
0276         cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
0277         for_each_online_cpu(i) {
0278             struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
0279
0280             if (i == cpu || !sib_cpu_ci->info_list)
0281                 continue;/* skip if itself or no cacheinfo */
0282
0283             sib_leaf = per_cpu_cacheinfo_idx(i, index);
0284             if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
0285                 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
0286                 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
0287             }
0288         }
0289         /* record the maximum cache line size */
0290         if (this_leaf->coherency_line_size > coherency_max_size)
0291             coherency_max_size = this_leaf->coherency_line_size;
0292     }
0293
0294     return 0;
0295 }
0296
0297 static void cache_shared_cpu_map_remove(unsigned int cpu)
0298 {
0299     struct cacheinfo *this_leaf, *sib_leaf;
0300     unsigned int sibling, index;
0301
0302     for (index = 0; index < cache_leaves(cpu); index++) {
0303         this_leaf = per_cpu_cacheinfo_idx(cpu, index);
0304         for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
0305             struct cpu_cacheinfo *sib_cpu_ci =
0306                         get_cpu_cacheinfo(sibling);
0307
0308             if (sibling == cpu || !sib_cpu_ci->info_list)
0309                 continue;/* skip if itself or no cacheinfo */
0310
0311             sib_leaf = per_cpu_cacheinfo_idx(sibling, index);
0312             cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
0313             cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
0314         }
0315         if (of_have_populated_dt())
0316             of_node_put(this_leaf->fw_token);
0317     }
0318 }
0319
0320 static void free_cache_attributes(unsigned int cpu)
0321 {
0322     if (!per_cpu_cacheinfo(cpu))
0323         return;
0324
0325     cache_shared_cpu_map_remove(cpu);
0326
0327     kfree(per_cpu_cacheinfo(cpu));
0328     per_cpu_cacheinfo(cpu) = NULL;
0329     cache_leaves(cpu) = 0;
0330 }
0331
0332 int __weak init_cache_level(unsigned int cpu)
0333 {
0334     return -ENOENT;
0335 }
0336
0337 int __weak populate_cache_leaves(unsigned int cpu)
0338 {
0339     return -ENOENT;
0340 }
0341
0342 int detect_cache_attributes(unsigned int cpu)
0343 {
0344     int ret;
0345
0346     /* Since early detection of the cacheinfo is allowed via this
0347      * function and this also gets called as CPU hotplug callbacks via
0348      * cacheinfo_cpu_online, the initialisation can be skipped and only
0349      * CPU maps can be updated as the CPU online status would be update
0350      * if called via cacheinfo_cpu_online path.
0351      */
0352     if (per_cpu_cacheinfo(cpu))
0353         goto update_cpu_map;
0354
0355     if (init_cache_level(cpu) || !cache_leaves(cpu))
0356         return -ENOENT;
0357
0358     per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
0359                      sizeof(struct cacheinfo), GFP_ATOMIC);
0360     if (per_cpu_cacheinfo(cpu) == NULL) {
0361         cache_leaves(cpu) = 0;
0362         return -ENOMEM;
0363     }
0364
0365     /*
0366      * populate_cache_leaves() may completely setup the cache leaves and
0367      * shared_cpu_map or it may leave it partially setup.
0368      */
0369     ret = populate_cache_leaves(cpu);
0370     if (ret)
0371         goto free_ci;
0372
0373 update_cpu_map:
0374     /*
0375      * For systems using DT for cache hierarchy, fw_token
0376      * and shared_cpu_map will be set up here only if they are
0377      * not populated already
0378      */
0379     ret = cache_shared_cpu_map_setup(cpu);
0380     if (ret) {
0381         pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
0382         goto free_ci;
0383     }
0384
0385     return 0;
0386
0387 free_ci:
0388     free_cache_attributes(cpu);
0389     return ret;
0390 }
0391
0392 /* pointer to cpuX/cache device */
0393 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
0394 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
0395
0396 static cpumask_t cache_dev_map;
0397
0398 /* pointer to array of devices for cpuX/cache/indexY */
0399 static DEFINE_PER_CPU(struct device **, ci_index_dev);
0400 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
0401 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
0402
0403 #define show_one(file_name, object)             \
0404 static ssize_t file_name##_show(struct device *dev,     \
0405         struct device_attribute *attr, char *buf)   \
0406 {                               \
0407     struct cacheinfo *this_leaf = dev_get_drvdata(dev); \
0408     return sysfs_emit(buf, "%u\n", this_leaf->object);  \
0409 }
0410
0411 show_one(id, id);
0412 show_one(level, level);
0413 show_one(coherency_line_size, coherency_line_size);
0414 show_one(number_of_sets, number_of_sets);
0415 show_one(physical_line_partition, physical_line_partition);
0416 show_one(ways_of_associativity, ways_of_associativity);
0417
0418 static ssize_t size_show(struct device *dev,
0419              struct device_attribute *attr, char *buf)
0420 {
0421     struct cacheinfo *this_leaf = dev_get_drvdata(dev);
0422
0423     return sysfs_emit(buf, "%uK\n", this_leaf->size >> 10);
0424 }
0425
0426 static ssize_t shared_cpu_map_show(struct device *dev,
0427                    struct device_attribute *attr, char *buf)
0428 {
0429     struct cacheinfo *this_leaf = dev_get_drvdata(dev);
0430     const struct cpumask *mask = &this_leaf->shared_cpu_map;
0431
0432     return sysfs_emit(buf, "%*pb\n", nr_cpu_ids, mask);
0433 }
0434
0435 static ssize_t shared_cpu_list_show(struct device *dev,
0436                     struct device_attribute *attr, char *buf)
0437 {
0438     struct cacheinfo *this_leaf = dev_get_drvdata(dev);
0439     const struct cpumask *mask = &this_leaf->shared_cpu_map;
0440
0441     return sysfs_emit(buf, "%*pbl\n", nr_cpu_ids, mask);
0442 }
0443
0444 static ssize_t type_show(struct device *dev,
0445              struct device_attribute *attr, char *buf)
0446 {
0447     struct cacheinfo *this_leaf = dev_get_drvdata(dev);
0448     const char *output;
0449
0450     switch (this_leaf->type) {
0451     case CACHE_TYPE_DATA:
0452         output = "Data";
0453         break;
0454     case CACHE_TYPE_INST:
0455         output = "Instruction";
0456         break;
0457     case CACHE_TYPE_UNIFIED:
0458         output = "Unified";
0459         break;
0460     default:
0461         return -EINVAL;
0462     }
0463
0464     return sysfs_emit(buf, "%s\n", output);
0465 }
0466
0467 static ssize_t allocation_policy_show(struct device *dev,
0468                       struct device_attribute *attr, char *buf)
0469 {
0470     struct cacheinfo *this_leaf = dev_get_drvdata(dev);
0471     unsigned int ci_attr = this_leaf->attributes;
0472     const char *output;
0473
0474     if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
0475         output = "ReadWriteAllocate";
0476     else if (ci_attr & CACHE_READ_ALLOCATE)
0477         output = "ReadAllocate";
0478     else if (ci_attr & CACHE_WRITE_ALLOCATE)
0479         output = "WriteAllocate";
0480     else
0481         return 0;
0482
0483     return sysfs_emit(buf, "%s\n", output);
0484 }
0485
0486 static ssize_t write_policy_show(struct device *dev,
0487                  struct device_attribute *attr, char *buf)
0488 {
0489     struct cacheinfo *this_leaf = dev_get_drvdata(dev);
0490     unsigned int ci_attr = this_leaf->attributes;
0491     int n = 0;
0492
0493     if (ci_attr & CACHE_WRITE_THROUGH)
0494         n = sysfs_emit(buf, "WriteThrough\n");
0495     else if (ci_attr & CACHE_WRITE_BACK)
0496         n = sysfs_emit(buf, "WriteBack\n");
0497     return n;
0498 }
0499
0500 static DEVICE_ATTR_RO(id);
0501 static DEVICE_ATTR_RO(level);
0502 static DEVICE_ATTR_RO(type);
0503 static DEVICE_ATTR_RO(coherency_line_size);
0504 static DEVICE_ATTR_RO(ways_of_associativity);
0505 static DEVICE_ATTR_RO(number_of_sets);
0506 static DEVICE_ATTR_RO(size);
0507 static DEVICE_ATTR_RO(allocation_policy);
0508 static DEVICE_ATTR_RO(write_policy);
0509 static DEVICE_ATTR_RO(shared_cpu_map);
0510 static DEVICE_ATTR_RO(shared_cpu_list);
0511 static DEVICE_ATTR_RO(physical_line_partition);
0512
0513 static struct attribute *cache_default_attrs[] = {
0514     &dev_attr_id.attr,
0515     &dev_attr_type.attr,
0516     &dev_attr_level.attr,
0517     &dev_attr_shared_cpu_map.attr,
0518     &dev_attr_shared_cpu_list.attr,
0519     &dev_attr_coherency_line_size.attr,
0520     &dev_attr_ways_of_associativity.attr,
0521     &dev_attr_number_of_sets.attr,
0522     &dev_attr_size.attr,
0523     &dev_attr_allocation_policy.attr,
0524     &dev_attr_write_policy.attr,
0525     &dev_attr_physical_line_partition.attr,
0526     NULL
0527 };
0528
0529 static umode_t
0530 cache_default_attrs_is_visible(struct kobject *kobj,
0531                    struct attribute *attr, int unused)
0532 {
0533     struct device *dev = kobj_to_dev(kobj);
0534     struct cacheinfo *this_leaf = dev_get_drvdata(dev);
0535     const struct cpumask *mask = &this_leaf->shared_cpu_map;
0536     umode_t mode = attr->mode;
0537
0538     if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
0539         return mode;
0540     if ((attr == &dev_attr_type.attr) && this_leaf->type)
0541         return mode;
0542     if ((attr == &dev_attr_level.attr) && this_leaf->level)
0543         return mode;
0544     if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
0545         return mode;
0546     if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
0547         return mode;
0548     if ((attr == &dev_attr_coherency_line_size.attr) &&
0549         this_leaf->coherency_line_size)
0550         return mode;
0551     if ((attr == &dev_attr_ways_of_associativity.attr) &&
0552         this_leaf->size) /* allow 0 = full associativity */
0553         return mode;
0554     if ((attr == &dev_attr_number_of_sets.attr) &&
0555         this_leaf->number_of_sets)
0556         return mode;
0557     if ((attr == &dev_attr_size.attr) && this_leaf->size)
0558         return mode;
0559     if ((attr == &dev_attr_write_policy.attr) &&
0560         (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
0561         return mode;
0562     if ((attr == &dev_attr_allocation_policy.attr) &&
0563         (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
0564         return mode;
0565     if ((attr == &dev_attr_physical_line_partition.attr) &&
0566         this_leaf->physical_line_partition)
0567         return mode;
0568
0569     return 0;
0570 }
0571
0572 static const struct attribute_group cache_default_group = {
0573     .attrs = cache_default_attrs,
0574     .is_visible = cache_default_attrs_is_visible,
0575 };
0576
0577 static const struct attribute_group *cache_default_groups[] = {
0578     &cache_default_group,
0579     NULL,
0580 };
0581
0582 static const struct attribute_group *cache_private_groups[] = {
0583     &cache_default_group,
0584     NULL, /* Place holder for private group */
0585     NULL,
0586 };
0587
0588 const struct attribute_group *
0589 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
0590 {
0591     return NULL;
0592 }
0593
0594 static const struct attribute_group **
0595 cache_get_attribute_groups(struct cacheinfo *this_leaf)
0596 {
0597     const struct attribute_group *priv_group =
0598             cache_get_priv_group(this_leaf);
0599
0600     if (!priv_group)
0601         return cache_default_groups;
0602
0603     if (!cache_private_groups[1])
0604         cache_private_groups[1] = priv_group;
0605
0606     return cache_private_groups;
0607 }
0608
0609 /* Add/Remove cache interface for CPU device */
0610 static void cpu_cache_sysfs_exit(unsigned int cpu)
0611 {
0612     int i;
0613     struct device *ci_dev;
0614
0615     if (per_cpu_index_dev(cpu)) {
0616         for (i = 0; i < cache_leaves(cpu); i++) {
0617             ci_dev = per_cache_index_dev(cpu, i);
0618             if (!ci_dev)
0619                 continue;
0620             device_unregister(ci_dev);
0621         }
0622         kfree(per_cpu_index_dev(cpu));
0623         per_cpu_index_dev(cpu) = NULL;
0624     }
0625     device_unregister(per_cpu_cache_dev(cpu));
0626     per_cpu_cache_dev(cpu) = NULL;
0627 }
0628
0629 static int cpu_cache_sysfs_init(unsigned int cpu)
0630 {
0631     struct device *dev = get_cpu_device(cpu);
0632
0633     if (per_cpu_cacheinfo(cpu) == NULL)
0634         return -ENOENT;
0635
0636     per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
0637     if (IS_ERR(per_cpu_cache_dev(cpu)))
0638         return PTR_ERR(per_cpu_cache_dev(cpu));
0639
0640     /* Allocate all required memory */
0641     per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
0642                      sizeof(struct device *), GFP_KERNEL);
0643     if (unlikely(per_cpu_index_dev(cpu) == NULL))
0644         goto err_out;
0645
0646     return 0;
0647
0648 err_out:
0649     cpu_cache_sysfs_exit(cpu);
0650     return -ENOMEM;
0651 }
0652
0653 static int cache_add_dev(unsigned int cpu)
0654 {
0655     unsigned int i;
0656     int rc;
0657     struct device *ci_dev, *parent;
0658     struct cacheinfo *this_leaf;
0659     const struct attribute_group **cache_groups;
0660
0661     rc = cpu_cache_sysfs_init(cpu);
0662     if (unlikely(rc < 0))
0663         return rc;
0664
0665     parent = per_cpu_cache_dev(cpu);
0666     for (i = 0; i < cache_leaves(cpu); i++) {
0667         this_leaf = per_cpu_cacheinfo_idx(cpu, i);
0668         if (this_leaf->disable_sysfs)
0669             continue;
0670         if (this_leaf->type == CACHE_TYPE_NOCACHE)
0671             break;
0672         cache_groups = cache_get_attribute_groups(this_leaf);
0673         ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
0674                        "index%1u", i);
0675         if (IS_ERR(ci_dev)) {
0676             rc = PTR_ERR(ci_dev);
0677             goto err;
0678         }
0679         per_cache_index_dev(cpu, i) = ci_dev;
0680     }
0681     cpumask_set_cpu(cpu, &cache_dev_map);
0682
0683     return 0;
0684 err:
0685     cpu_cache_sysfs_exit(cpu);
0686     return rc;
0687 }
0688
0689 static int cacheinfo_cpu_online(unsigned int cpu)
0690 {
0691     int rc = detect_cache_attributes(cpu);
0692
0693     if (rc)
0694         return rc;
0695     rc = cache_add_dev(cpu);
0696     if (rc)
0697         free_cache_attributes(cpu);
0698     return rc;
0699 }
0700
0701 static int cacheinfo_cpu_pre_down(unsigned int cpu)
0702 {
0703     if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
0704         cpu_cache_sysfs_exit(cpu);
0705
0706     free_cache_attributes(cpu);
0707     return 0;
0708 }
0709
0710 static int __init cacheinfo_sysfs_init(void)
0711 {
0712     return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE,
0713                  "base/cacheinfo:online",
0714                  cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
0715 }
0716 device_initcall(cacheinfo_sysfs_init);