[RFC,1/3] drivers: base: support cpu cache information interface to userspace via sysfs

Message ID	1389209168-17189-2-git-send-email-sudeep.holla@arm.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Sudeep Holla <sudeep.holla@arm.com> To: x86@kernel.org, linuxppc-dev@lists.ozlabs.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH RFC 1/3] drivers: base: support cpu cache information interface to userspace via sysfs Date: Wed, 8 Jan 2014 19:26:06 +0000 Message-Id: <1389209168-17189-2-git-send-email-sudeep.holla@arm.com> In-Reply-To: <1389209168-17189-1-git-send-email-sudeep.holla@arm.com> References: <1389209168-17189-1-git-send-email-sudeep.holla@arm.com> Cc: Rob Herring <robh@kernel.org>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Ashok Raj <ashok.raj@intel.com>, sudeep.holla@arm.com Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 94e8a80..76f07c8 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -4,7 +4,7 @@ obj-y := core.o bus.o dd.o syscore.o \ driver.o class.o platform.o \ cpu.o firmware.o init.o map.o devres.o \ attribute_container.o transport_class.o \ - topology.o + topology.o cacheinfo.o obj-$(CONFIG_DEVTMPFS) += devtmpfs.o obj-$(CONFIG_DMA_CMA) += dma-contiguous.o obj-y += power/ diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c new file mode 100644 index 0000000..f436c31 --- /dev/null +++ b/drivers/base/cacheinfo.c @@ -0,0 +1,296 @@ +/* + * cacheinfo support - processor cache information via sysfs + * + * Copyright (C) 2013 ARM Ltd. + * All Rights Reserved + * + * Author: Sudeep Holla <sudeep.holla@arm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ +#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/kobject.h> +#include <linux/of.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/smp.h> +#include <linux/sysfs.h> + +struct cache_attr { + struct attribute attr; + ssize_t(*show) (unsigned int, unsigned short, char *); + ssize_t(*store) (unsigned int, unsigned short, const char *, size_t); +}; + +/* pointer to kobject for cpuX/cache */ +static DEFINE_PER_CPU(struct kobject *, ci_cache_kobject); +#define per_cpu_cache_kobject(cpu) (per_cpu(ci_cache_kobject, cpu)) + +struct index_kobject { + struct kobject kobj; + unsigned int cpu; + unsigned short index; +}; + +static cpumask_t cache_dev_map; + +/* pointer to array of kobjects for cpuX/cache/indexY */ +static DEFINE_PER_CPU(struct index_kobject *, ci_index_kobject); +#define per_cpu_index_kobject(cpu) (per_cpu(ci_index_kobject, cpu)) +#define INDEX_KOBJECT_PTR(cpu, idx) (&((per_cpu_index_kobject(cpu))[idx])) + +#define show_one_plus(file_name, object) \ +static ssize_t show_##file_name(unsigned int cpu, unsigned short index, \ + char *buf) \ +{ \ + return sprintf(buf, "%d\n", cacheinfo_##object(cpu, index)); \ +} + +show_one_plus(level, level); +show_one_plus(coherency_line_size, linesize); +show_one_plus(ways_of_associativity, associativity); +show_one_plus(number_of_sets, sets); + +static ssize_t show_size(unsigned int cpu, unsigned short index, char *buf) +{ + return sprintf(buf, "%dK\n", cacheinfo_size(cpu, index) / 1024); +} + +static ssize_t show_shared_cpu_map_func(unsigned int cpu, unsigned short index, + int type, char *buf) +{ + ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; + int n = 0; + + if (len > 1) { + const struct cpumask *mask = cacheinfo_cpumap(cpu, index); + n = type ? + cpulist_scnprintf(buf, len - 2, mask) : + cpumask_scnprintf(buf, len - 2, mask); + buf[n++] = '\n'; + buf[n] = '\0'; + } + return n; +} + +static inline ssize_t show_shared_cpu_map(unsigned int cpu, + unsigned short index, char *buf) +{ + return show_shared_cpu_map_func(cpu, index, 0, buf); +} + +static inline ssize_t show_shared_cpu_list(unsigned int cpu, + unsigned short index, char *buf) +{ + return show_shared_cpu_map_func(cpu, index, 1, buf); +} + +static ssize_t show_type(unsigned int cpu, unsigned short index, char *buf) +{ + return sprintf(buf, cacheinfo_type(cpu, index)); +} + +#define to_object(k) container_of(k, struct index_kobject, kobj) +#define to_attr(a) container_of(a, struct cache_attr, attr) + +#define define_one_ro(_name) \ +static struct cache_attr _name = \ + __ATTR(_name, 0444, show_##_name, NULL) + +define_one_ro(level); +define_one_ro(type); +define_one_ro(coherency_line_size); +define_one_ro(ways_of_associativity); +define_one_ro(number_of_sets); +define_one_ro(size); +define_one_ro(shared_cpu_map); +define_one_ro(shared_cpu_list); + +static struct attribute *default_attrs[] = { + &type.attr, + &level.attr, + &coherency_line_size.attr, + &ways_of_associativity.attr, + &number_of_sets.attr, + &size.attr, + &shared_cpu_map.attr, + &shared_cpu_list.attr, + NULL +}; + +static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) +{ + struct cache_attr *fattr = to_attr(attr); + struct index_kobject *this_leaf = to_object(kobj); + ssize_t ret; + + ret = fattr->show ? + fattr->show(this_leaf->cpu, this_leaf->index, buf) : 0; + return ret; +} + +static ssize_t store(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t count) +{ + struct cache_attr *fattr = to_attr(attr); + struct index_kobject *this_leaf = to_object(kobj); + ssize_t ret; + + ret = fattr->store ? + fattr->store(this_leaf->cpu, this_leaf->index, buf, count) : 0; + return ret; +} + +static const struct sysfs_ops sysfs_ops = { + .show = show, + .store = store, +}; + +static struct kobj_type ktype_cache = { + .sysfs_ops = &sysfs_ops, + .default_attrs = default_attrs, +}; + +static struct kobj_type ktype_percpu_entry = { + .sysfs_ops = &sysfs_ops, +}; + +static void cpu_cache_sysfs_exit(unsigned int cpu) +{ + kfree(per_cpu_cache_kobject(cpu)); + kfree(per_cpu_index_kobject(cpu)); + per_cpu_cache_kobject(cpu) = NULL; + per_cpu_index_kobject(cpu) = NULL; +} + +static int cpu_cache_sysfs_init(unsigned int cpu) +{ + if (!cacheinfo_populated(cpu)) + return -ENOENT; + + /* Allocate all required memory */ + per_cpu_cache_kobject(cpu) = + kzalloc(sizeof(struct kobject), GFP_KERNEL); + if (unlikely(per_cpu_cache_kobject(cpu) == NULL)) + goto err_out; + + per_cpu_index_kobject(cpu) = kzalloc(sizeof(struct index_kobject) * + cacheinfo_leaf_count(cpu), GFP_KERNEL); + if (unlikely(per_cpu_index_kobject(cpu) == NULL)) + goto err_out; + + return 0; + +err_out: + cpu_cache_sysfs_exit(cpu); + return -ENOMEM; +} + +/* Add/Remove cache interface for CPU device */ +static int cache_add_dev(unsigned int cpu) +{ + struct device *dev = get_cpu_device(cpu); + struct index_kobject *this_object; + unsigned long i, j; + int rc; + + rc = cpu_cache_sysfs_init(cpu); + if (unlikely(rc < 0)) + return rc; + + rc = kobject_init_and_add(per_cpu_cache_kobject(cpu), + &ktype_percpu_entry, + &dev->kobj, "%s", "cache"); + if (rc < 0) { + cpu_cache_sysfs_exit(cpu); + return rc; + } + + for (i = 0; i < cacheinfo_leaf_count(cpu); i++) { + this_object = INDEX_KOBJECT_PTR(cpu, i); + this_object->cpu = cpu; + this_object->index = i; + + rc = kobject_init_and_add(&(this_object->kobj), + &ktype_cache, + per_cpu_cache_kobject(cpu), + "index%1lu", i); + if (unlikely(rc)) { + for (j = 0; j < i; j++) + kobject_put(&(INDEX_KOBJECT_PTR(cpu, j)->kobj)); + kobject_put(per_cpu_cache_kobject(cpu)); + cpu_cache_sysfs_exit(cpu); + return rc; + } + kobject_uevent(&(this_object->kobj), KOBJ_ADD); + } + cpumask_set_cpu(cpu, &cache_dev_map); + + kobject_uevent(per_cpu_cache_kobject(cpu), KOBJ_ADD); + return 0; +} + +static void cache_remove_dev(unsigned int cpu) +{ + unsigned long i; + + if (!cpumask_test_cpu(cpu, &cache_dev_map)) + return; + cpumask_clear_cpu(cpu, &cache_dev_map); + + for (i = 0; i < cacheinfo_leaf_count(cpu); i++) + kobject_put(&(INDEX_KOBJECT_PTR(cpu, i)->kobj)); + kobject_put(per_cpu_cache_kobject(cpu)); + cpu_cache_sysfs_exit(cpu); +} + +static int cacheinfo_cpu_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + unsigned int cpu = (unsigned long)hcpu; + int rc = 0; + + switch (action) { + case CPU_UP_PREPARE: + case CPU_UP_PREPARE_FROZEN: + rc = cache_add_dev(cpu); + break; + case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: + case CPU_DEAD: + case CPU_DEAD_FROZEN: + cache_remove_dev(cpu); + break; + } + return notifier_from_errno(rc); +} + +static int __init cacheinfo_sysfs_init(void) +{ + int cpu; + int rc; + + for_each_online_cpu(cpu) { + rc = cache_add_dev(cpu); + if (rc) { + pr_err("error populating cacheinfo..cpu%d\n", cpu); + return rc; + } + } + hotcpu_notifier(cacheinfo_cpu_callback, 0); + return 0; +} + +device_initcall(cacheinfo_sysfs_init); diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h new file mode 100644 index 0000000..917eccf --- /dev/null +++ b/include/linux/cacheinfo.h @@ -0,0 +1,43 @@ +#ifndef _LINUX_CACHEINFO_H +#define _LINUX_CACHEINFO_H + +#include <linux/cpumask.h> +#include <linux/bitops.h> +#include <linux/mmzone.h> +#include <linux/smp.h> +#include <linux/percpu.h> + +int __weak cacheinfo_leaf_count(unsigned int cpu) { return 0; } +bool __weak cacheinfo_populated(unsigned int cpu) { return 0; } +unsigned int __weak cacheinfo_level(unsigned int cpu, unsigned short idx) +{ + return 0; +} +unsigned int __weak cacheinfo_linesize(unsigned int cpu, unsigned short idx) +{ + return 0; +} +unsigned int __weak cacheinfo_associativity(unsigned int cpu, + unsigned short idx) +{ + return 0; +} +unsigned int __weak cacheinfo_sets(unsigned int cpu, unsigned short idx) +{ + return 0; +} +unsigned int __weak cacheinfo_size(unsigned int cpu, unsigned short idx) +{ + return 0; +} +char * __weak cacheinfo_type(unsigned int cpu, unsigned short idx) +{ + return "Unknown\n"; +} +const struct cpumask * __weak cacheinfo_cpumap(unsigned int cpu, + unsigned short idx) +{ + return cpumask_of(cpu); +} + +#endif /* _LINUX_CACHEINFO_H */

[RFC,1/3] drivers: base: support cpu cache information interface to userspace via sysfs

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