linux/arch/powerpc/kernel/cacheinfo.c
Dave Olson f7e9e35836 powerpc: Fix missing L2 cache size in /sys/devices/system/cpu
This problem appears to have been introduced in 2.6.29 by commit
93197a36a9 "Rewrite sysfs processor cache info code".

This caused lscpu to error out on at least e500v2 devices, eg:

  error: cannot open /sys/devices/system/cpu/cpu0/cache/index2/size: No such file or directory

Some embedded powerpc systems use cache-size in DTS for the unified L2
cache size, not d-cache-size, so we need to allow for both DTS names.
Added a new CACHE_TYPE_UNIFIED_D cache_type_info structure to handle
this.

Fixes: 93197a36a9 ("powerpc: Rewrite sysfs processor cache info code")
Signed-off-by: Dave Olson <olson@cumulusnetworks.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-04-11 20:49:28 +10:00

871 lines
21 KiB
C

/*
* Processor cache information made available to userspace via sysfs;
* intended to be compatible with x86 intel_cacheinfo implementation.
*
* Copyright 2008 IBM Corporation
* Author: Nathan Lynch
*
* 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.
*/
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <asm/prom.h>
#include "cacheinfo.h"
/* per-cpu object for tracking:
* - a "cache" kobject for the top-level directory
* - a list of "index" objects representing the cpu's local cache hierarchy
*/
struct cache_dir {
struct kobject *kobj; /* bare (not embedded) kobject for cache
* directory */
struct cache_index_dir *index; /* list of index objects */
};
/* "index" object: each cpu's cache directory has an index
* subdirectory corresponding to a cache object associated with the
* cpu. This object's lifetime is managed via the embedded kobject.
*/
struct cache_index_dir {
struct kobject kobj;
struct cache_index_dir *next; /* next index in parent directory */
struct cache *cache;
};
/* Template for determining which OF properties to query for a given
* cache type */
struct cache_type_info {
const char *name;
const char *size_prop;
/* Allow for both [di]-cache-line-size and
* [di]-cache-block-size properties. According to the PowerPC
* Processor binding, -line-size should be provided if it
* differs from the cache block size (that which is operated
* on by cache instructions), so we look for -line-size first.
* See cache_get_line_size(). */
const char *line_size_props[2];
const char *nr_sets_prop;
};
/* These are used to index the cache_type_info array. */
#define CACHE_TYPE_UNIFIED 0 /* cache-size, cache-block-size, etc. */
#define CACHE_TYPE_UNIFIED_D 1 /* d-cache-size, d-cache-block-size, etc */
#define CACHE_TYPE_INSTRUCTION 2
#define CACHE_TYPE_DATA 3
static const struct cache_type_info cache_type_info[] = {
{
/* Embedded systems that use cache-size, cache-block-size,
* etc. for the Unified (typically L2) cache. */
.name = "Unified",
.size_prop = "cache-size",
.line_size_props = { "cache-line-size",
"cache-block-size", },
.nr_sets_prop = "cache-sets",
},
{
/* PowerPC Processor binding says the [di]-cache-*
* must be equal on unified caches, so just use
* d-cache properties. */
.name = "Unified",
.size_prop = "d-cache-size",
.line_size_props = { "d-cache-line-size",
"d-cache-block-size", },
.nr_sets_prop = "d-cache-sets",
},
{
.name = "Instruction",
.size_prop = "i-cache-size",
.line_size_props = { "i-cache-line-size",
"i-cache-block-size", },
.nr_sets_prop = "i-cache-sets",
},
{
.name = "Data",
.size_prop = "d-cache-size",
.line_size_props = { "d-cache-line-size",
"d-cache-block-size", },
.nr_sets_prop = "d-cache-sets",
},
};
/* Cache object: each instance of this corresponds to a distinct cache
* in the system. There are separate objects for Harvard caches: one
* each for instruction and data, and each refers to the same OF node.
* The refcount of the OF node is elevated for the lifetime of the
* cache object. A cache object is released when its shared_cpu_map
* is cleared (see cache_cpu_clear).
*
* A cache object is on two lists: an unsorted global list
* (cache_list) of cache objects; and a singly-linked list
* representing the local cache hierarchy, which is ordered by level
* (e.g. L1d -> L1i -> L2 -> L3).
*/
struct cache {
struct device_node *ofnode; /* OF node for this cache, may be cpu */
struct cpumask shared_cpu_map; /* online CPUs using this cache */
int type; /* split cache disambiguation */
int level; /* level not explicit in device tree */
struct list_head list; /* global list of cache objects */
struct cache *next_local; /* next cache of >= level */
};
static DEFINE_PER_CPU(struct cache_dir *, cache_dir_pcpu);
/* traversal/modification of this list occurs only at cpu hotplug time;
* access is serialized by cpu hotplug locking
*/
static LIST_HEAD(cache_list);
static struct cache_index_dir *kobj_to_cache_index_dir(struct kobject *k)
{
return container_of(k, struct cache_index_dir, kobj);
}
static const char *cache_type_string(const struct cache *cache)
{
return cache_type_info[cache->type].name;
}
static void cache_init(struct cache *cache, int type, int level,
struct device_node *ofnode)
{
cache->type = type;
cache->level = level;
cache->ofnode = of_node_get(ofnode);
INIT_LIST_HEAD(&cache->list);
list_add(&cache->list, &cache_list);
}
static struct cache *new_cache(int type, int level, struct device_node *ofnode)
{
struct cache *cache;
cache = kzalloc(sizeof(*cache), GFP_KERNEL);
if (cache)
cache_init(cache, type, level, ofnode);
return cache;
}
static void release_cache_debugcheck(struct cache *cache)
{
struct cache *iter;
list_for_each_entry(iter, &cache_list, list)
WARN_ONCE(iter->next_local == cache,
"cache for %s(%s) refers to cache for %s(%s)\n",
iter->ofnode->full_name,
cache_type_string(iter),
cache->ofnode->full_name,
cache_type_string(cache));
}
static void release_cache(struct cache *cache)
{
if (!cache)
return;
pr_debug("freeing L%d %s cache for %s\n", cache->level,
cache_type_string(cache), cache->ofnode->full_name);
release_cache_debugcheck(cache);
list_del(&cache->list);
of_node_put(cache->ofnode);
kfree(cache);
}
static void cache_cpu_set(struct cache *cache, int cpu)
{
struct cache *next = cache;
while (next) {
WARN_ONCE(cpumask_test_cpu(cpu, &next->shared_cpu_map),
"CPU %i already accounted in %s(%s)\n",
cpu, next->ofnode->full_name,
cache_type_string(next));
cpumask_set_cpu(cpu, &next->shared_cpu_map);
next = next->next_local;
}
}
static int cache_size(const struct cache *cache, unsigned int *ret)
{
const char *propname;
const __be32 *cache_size;
propname = cache_type_info[cache->type].size_prop;
cache_size = of_get_property(cache->ofnode, propname, NULL);
if (!cache_size)
return -ENODEV;
*ret = of_read_number(cache_size, 1);
return 0;
}
static int cache_size_kb(const struct cache *cache, unsigned int *ret)
{
unsigned int size;
if (cache_size(cache, &size))
return -ENODEV;
*ret = size / 1024;
return 0;
}
/* not cache_line_size() because that's a macro in include/linux/cache.h */
static int cache_get_line_size(const struct cache *cache, unsigned int *ret)
{
const __be32 *line_size;
int i, lim;
lim = ARRAY_SIZE(cache_type_info[cache->type].line_size_props);
for (i = 0; i < lim; i++) {
const char *propname;
propname = cache_type_info[cache->type].line_size_props[i];
line_size = of_get_property(cache->ofnode, propname, NULL);
if (line_size)
break;
}
if (!line_size)
return -ENODEV;
*ret = of_read_number(line_size, 1);
return 0;
}
static int cache_nr_sets(const struct cache *cache, unsigned int *ret)
{
const char *propname;
const __be32 *nr_sets;
propname = cache_type_info[cache->type].nr_sets_prop;
nr_sets = of_get_property(cache->ofnode, propname, NULL);
if (!nr_sets)
return -ENODEV;
*ret = of_read_number(nr_sets, 1);
return 0;
}
static int cache_associativity(const struct cache *cache, unsigned int *ret)
{
unsigned int line_size;
unsigned int nr_sets;
unsigned int size;
if (cache_nr_sets(cache, &nr_sets))
goto err;
/* If the cache is fully associative, there is no need to
* check the other properties.
*/
if (nr_sets == 1) {
*ret = 0;
return 0;
}
if (cache_get_line_size(cache, &line_size))
goto err;
if (cache_size(cache, &size))
goto err;
if (!(nr_sets > 0 && size > 0 && line_size > 0))
goto err;
*ret = (size / nr_sets) / line_size;
return 0;
err:
return -ENODEV;
}
/* helper for dealing with split caches */
static struct cache *cache_find_first_sibling(struct cache *cache)
{
struct cache *iter;
if (cache->type == CACHE_TYPE_UNIFIED ||
cache->type == CACHE_TYPE_UNIFIED_D)
return cache;
list_for_each_entry(iter, &cache_list, list)
if (iter->ofnode == cache->ofnode && iter->next_local == cache)
return iter;
return cache;
}
/* return the first cache on a local list matching node */
static struct cache *cache_lookup_by_node(const struct device_node *node)
{
struct cache *cache = NULL;
struct cache *iter;
list_for_each_entry(iter, &cache_list, list) {
if (iter->ofnode != node)
continue;
cache = cache_find_first_sibling(iter);
break;
}
return cache;
}
static bool cache_node_is_unified(const struct device_node *np)
{
return of_get_property(np, "cache-unified", NULL);
}
/*
* Unified caches can have two different sets of tags. Most embedded
* use cache-size, etc. for the unified cache size, but open firmware systems
* use d-cache-size, etc. Check on initialization for which type we have, and
* return the appropriate structure type. Assume it's embedded if it isn't
* open firmware. If it's yet a 3rd type, then there will be missing entries
* in /sys/devices/system/cpu/cpu0/cache/index2/, and this code will need
* to be extended further.
*/
static int cache_is_unified_d(const struct device_node *np)
{
return of_get_property(np,
cache_type_info[CACHE_TYPE_UNIFIED_D].size_prop, NULL) ?
CACHE_TYPE_UNIFIED_D : CACHE_TYPE_UNIFIED;
}
/*
*/
static struct cache *cache_do_one_devnode_unified(struct device_node *node, int level)
{
pr_debug("creating L%d ucache for %s\n", level, node->full_name);
return new_cache(cache_is_unified_d(node), level, node);
}
static struct cache *cache_do_one_devnode_split(struct device_node *node,
int level)
{
struct cache *dcache, *icache;
pr_debug("creating L%d dcache and icache for %s\n", level,
node->full_name);
dcache = new_cache(CACHE_TYPE_DATA, level, node);
icache = new_cache(CACHE_TYPE_INSTRUCTION, level, node);
if (!dcache || !icache)
goto err;
dcache->next_local = icache;
return dcache;
err:
release_cache(dcache);
release_cache(icache);
return NULL;
}
static struct cache *cache_do_one_devnode(struct device_node *node, int level)
{
struct cache *cache;
if (cache_node_is_unified(node))
cache = cache_do_one_devnode_unified(node, level);
else
cache = cache_do_one_devnode_split(node, level);
return cache;
}
static struct cache *cache_lookup_or_instantiate(struct device_node *node,
int level)
{
struct cache *cache;
cache = cache_lookup_by_node(node);
WARN_ONCE(cache && cache->level != level,
"cache level mismatch on lookup (got %d, expected %d)\n",
cache->level, level);
if (!cache)
cache = cache_do_one_devnode(node, level);
return cache;
}
static void link_cache_lists(struct cache *smaller, struct cache *bigger)
{
while (smaller->next_local) {
if (smaller->next_local == bigger)
return; /* already linked */
smaller = smaller->next_local;
}
smaller->next_local = bigger;
}
static void do_subsidiary_caches_debugcheck(struct cache *cache)
{
WARN_ON_ONCE(cache->level != 1);
WARN_ON_ONCE(strcmp(cache->ofnode->type, "cpu"));
}
static void do_subsidiary_caches(struct cache *cache)
{
struct device_node *subcache_node;
int level = cache->level;
do_subsidiary_caches_debugcheck(cache);
while ((subcache_node = of_find_next_cache_node(cache->ofnode))) {
struct cache *subcache;
level++;
subcache = cache_lookup_or_instantiate(subcache_node, level);
of_node_put(subcache_node);
if (!subcache)
break;
link_cache_lists(cache, subcache);
cache = subcache;
}
}
static struct cache *cache_chain_instantiate(unsigned int cpu_id)
{
struct device_node *cpu_node;
struct cache *cpu_cache = NULL;
pr_debug("creating cache object(s) for CPU %i\n", cpu_id);
cpu_node = of_get_cpu_node(cpu_id, NULL);
WARN_ONCE(!cpu_node, "no OF node found for CPU %i\n", cpu_id);
if (!cpu_node)
goto out;
cpu_cache = cache_lookup_or_instantiate(cpu_node, 1);
if (!cpu_cache)
goto out;
do_subsidiary_caches(cpu_cache);
cache_cpu_set(cpu_cache, cpu_id);
out:
of_node_put(cpu_node);
return cpu_cache;
}
static struct cache_dir *cacheinfo_create_cache_dir(unsigned int cpu_id)
{
struct cache_dir *cache_dir;
struct device *dev;
struct kobject *kobj = NULL;
dev = get_cpu_device(cpu_id);
WARN_ONCE(!dev, "no dev for CPU %i\n", cpu_id);
if (!dev)
goto err;
kobj = kobject_create_and_add("cache", &dev->kobj);
if (!kobj)
goto err;
cache_dir = kzalloc(sizeof(*cache_dir), GFP_KERNEL);
if (!cache_dir)
goto err;
cache_dir->kobj = kobj;
WARN_ON_ONCE(per_cpu(cache_dir_pcpu, cpu_id) != NULL);
per_cpu(cache_dir_pcpu, cpu_id) = cache_dir;
return cache_dir;
err:
kobject_put(kobj);
return NULL;
}
static void cache_index_release(struct kobject *kobj)
{
struct cache_index_dir *index;
index = kobj_to_cache_index_dir(kobj);
pr_debug("freeing index directory for L%d %s cache\n",
index->cache->level, cache_type_string(index->cache));
kfree(index);
}
static ssize_t cache_index_show(struct kobject *k, struct attribute *attr, char *buf)
{
struct kobj_attribute *kobj_attr;
kobj_attr = container_of(attr, struct kobj_attribute, attr);
return kobj_attr->show(k, kobj_attr, buf);
}
static struct cache *index_kobj_to_cache(struct kobject *k)
{
struct cache_index_dir *index;
index = kobj_to_cache_index_dir(k);
return index->cache;
}
static ssize_t size_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
{
unsigned int size_kb;
struct cache *cache;
cache = index_kobj_to_cache(k);
if (cache_size_kb(cache, &size_kb))
return -ENODEV;
return sprintf(buf, "%uK\n", size_kb);
}
static struct kobj_attribute cache_size_attr =
__ATTR(size, 0444, size_show, NULL);
static ssize_t line_size_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
{
unsigned int line_size;
struct cache *cache;
cache = index_kobj_to_cache(k);
if (cache_get_line_size(cache, &line_size))
return -ENODEV;
return sprintf(buf, "%u\n", line_size);
}
static struct kobj_attribute cache_line_size_attr =
__ATTR(coherency_line_size, 0444, line_size_show, NULL);
static ssize_t nr_sets_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
{
unsigned int nr_sets;
struct cache *cache;
cache = index_kobj_to_cache(k);
if (cache_nr_sets(cache, &nr_sets))
return -ENODEV;
return sprintf(buf, "%u\n", nr_sets);
}
static struct kobj_attribute cache_nr_sets_attr =
__ATTR(number_of_sets, 0444, nr_sets_show, NULL);
static ssize_t associativity_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
{
unsigned int associativity;
struct cache *cache;
cache = index_kobj_to_cache(k);
if (cache_associativity(cache, &associativity))
return -ENODEV;
return sprintf(buf, "%u\n", associativity);
}
static struct kobj_attribute cache_assoc_attr =
__ATTR(ways_of_associativity, 0444, associativity_show, NULL);
static ssize_t type_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
{
struct cache *cache;
cache = index_kobj_to_cache(k);
return sprintf(buf, "%s\n", cache_type_string(cache));
}
static struct kobj_attribute cache_type_attr =
__ATTR(type, 0444, type_show, NULL);
static ssize_t level_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
{
struct cache_index_dir *index;
struct cache *cache;
index = kobj_to_cache_index_dir(k);
cache = index->cache;
return sprintf(buf, "%d\n", cache->level);
}
static struct kobj_attribute cache_level_attr =
__ATTR(level, 0444, level_show, NULL);
static ssize_t shared_cpu_map_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
{
struct cache_index_dir *index;
struct cache *cache;
int ret;
index = kobj_to_cache_index_dir(k);
cache = index->cache;
ret = scnprintf(buf, PAGE_SIZE - 1, "%*pb\n",
cpumask_pr_args(&cache->shared_cpu_map));
buf[ret++] = '\n';
buf[ret] = '\0';
return ret;
}
static struct kobj_attribute cache_shared_cpu_map_attr =
__ATTR(shared_cpu_map, 0444, shared_cpu_map_show, NULL);
/* Attributes which should always be created -- the kobject/sysfs core
* does this automatically via kobj_type->default_attrs. This is the
* minimum data required to uniquely identify a cache.
*/
static struct attribute *cache_index_default_attrs[] = {
&cache_type_attr.attr,
&cache_level_attr.attr,
&cache_shared_cpu_map_attr.attr,
NULL,
};
/* Attributes which should be created if the cache device node has the
* right properties -- see cacheinfo_create_index_opt_attrs
*/
static struct kobj_attribute *cache_index_opt_attrs[] = {
&cache_size_attr,
&cache_line_size_attr,
&cache_nr_sets_attr,
&cache_assoc_attr,
};
static const struct sysfs_ops cache_index_ops = {
.show = cache_index_show,
};
static struct kobj_type cache_index_type = {
.release = cache_index_release,
.sysfs_ops = &cache_index_ops,
.default_attrs = cache_index_default_attrs,
};
static void cacheinfo_create_index_opt_attrs(struct cache_index_dir *dir)
{
const char *cache_name;
const char *cache_type;
struct cache *cache;
char *buf;
int i;
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf)
return;
cache = dir->cache;
cache_name = cache->ofnode->full_name;
cache_type = cache_type_string(cache);
/* We don't want to create an attribute that can't provide a
* meaningful value. Check the return value of each optional
* attribute's ->show method before registering the
* attribute.
*/
for (i = 0; i < ARRAY_SIZE(cache_index_opt_attrs); i++) {
struct kobj_attribute *attr;
ssize_t rc;
attr = cache_index_opt_attrs[i];
rc = attr->show(&dir->kobj, attr, buf);
if (rc <= 0) {
pr_debug("not creating %s attribute for "
"%s(%s) (rc = %zd)\n",
attr->attr.name, cache_name,
cache_type, rc);
continue;
}
if (sysfs_create_file(&dir->kobj, &attr->attr))
pr_debug("could not create %s attribute for %s(%s)\n",
attr->attr.name, cache_name, cache_type);
}
kfree(buf);
}
static void cacheinfo_create_index_dir(struct cache *cache, int index,
struct cache_dir *cache_dir)
{
struct cache_index_dir *index_dir;
int rc;
index_dir = kzalloc(sizeof(*index_dir), GFP_KERNEL);
if (!index_dir)
goto err;
index_dir->cache = cache;
rc = kobject_init_and_add(&index_dir->kobj, &cache_index_type,
cache_dir->kobj, "index%d", index);
if (rc)
goto err;
index_dir->next = cache_dir->index;
cache_dir->index = index_dir;
cacheinfo_create_index_opt_attrs(index_dir);
return;
err:
kfree(index_dir);
}
static void cacheinfo_sysfs_populate(unsigned int cpu_id,
struct cache *cache_list)
{
struct cache_dir *cache_dir;
struct cache *cache;
int index = 0;
cache_dir = cacheinfo_create_cache_dir(cpu_id);
if (!cache_dir)
return;
cache = cache_list;
while (cache) {
cacheinfo_create_index_dir(cache, index, cache_dir);
index++;
cache = cache->next_local;
}
}
void cacheinfo_cpu_online(unsigned int cpu_id)
{
struct cache *cache;
cache = cache_chain_instantiate(cpu_id);
if (!cache)
return;
cacheinfo_sysfs_populate(cpu_id, cache);
}
/* functions needed to remove cache entry for cpu offline or suspend/resume */
#if (defined(CONFIG_PPC_PSERIES) && defined(CONFIG_SUSPEND)) || \
defined(CONFIG_HOTPLUG_CPU)
static struct cache *cache_lookup_by_cpu(unsigned int cpu_id)
{
struct device_node *cpu_node;
struct cache *cache;
cpu_node = of_get_cpu_node(cpu_id, NULL);
WARN_ONCE(!cpu_node, "no OF node found for CPU %i\n", cpu_id);
if (!cpu_node)
return NULL;
cache = cache_lookup_by_node(cpu_node);
of_node_put(cpu_node);
return cache;
}
static void remove_index_dirs(struct cache_dir *cache_dir)
{
struct cache_index_dir *index;
index = cache_dir->index;
while (index) {
struct cache_index_dir *next;
next = index->next;
kobject_put(&index->kobj);
index = next;
}
}
static void remove_cache_dir(struct cache_dir *cache_dir)
{
remove_index_dirs(cache_dir);
/* Remove cache dir from sysfs */
kobject_del(cache_dir->kobj);
kobject_put(cache_dir->kobj);
kfree(cache_dir);
}
static void cache_cpu_clear(struct cache *cache, int cpu)
{
while (cache) {
struct cache *next = cache->next_local;
WARN_ONCE(!cpumask_test_cpu(cpu, &cache->shared_cpu_map),
"CPU %i not accounted in %s(%s)\n",
cpu, cache->ofnode->full_name,
cache_type_string(cache));
cpumask_clear_cpu(cpu, &cache->shared_cpu_map);
/* Release the cache object if all the cpus using it
* are offline */
if (cpumask_empty(&cache->shared_cpu_map))
release_cache(cache);
cache = next;
}
}
void cacheinfo_cpu_offline(unsigned int cpu_id)
{
struct cache_dir *cache_dir;
struct cache *cache;
/* Prevent userspace from seeing inconsistent state - remove
* the sysfs hierarchy first */
cache_dir = per_cpu(cache_dir_pcpu, cpu_id);
/* careful, sysfs population may have failed */
if (cache_dir)
remove_cache_dir(cache_dir);
per_cpu(cache_dir_pcpu, cpu_id) = NULL;
/* clear the CPU's bit in its cache chain, possibly freeing
* cache objects */
cache = cache_lookup_by_cpu(cpu_id);
if (cache)
cache_cpu_clear(cache, cpu_id);
}
#endif /* (CONFIG_PPC_PSERIES && CONFIG_SUSPEND) || CONFIG_HOTPLUG_CPU */