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linux-next/drivers/base/cacheinfo.c
Borislav Petkov 2110d70c5e cpu/cacheinfo: Fix teardown path
Philip Müller reported a hang when booting 32-bit 4.1 kernel on an AMD
box. A fragment of the splat was enough to pinpoint the issue:

  task: f58e0000 ti: f58e8000 task.ti: f58e800
  EIP: 0060:[<c135a903>] EFLAGS: 00010206 CPU: 0
  EIP is at free_cache_attributes+0x83/0xd0
  EAX: 00000001 EBX: f589d46c ECX: 00000090 EDX: 360c2000
  ESI: 00000000 EDI: c1724a80 EBP: f58e9ec0 ESP: f58e9ea0
   DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
  CR0: 8005003b CR2: 000000ac CR3: 01731000 CR4: 000006d0

cache_shared_cpu_map_setup() did check sibling CPUs cacheinfo descriptor
while the respective teardown path cache_shared_cpu_map_remove() didn't.
Fix that.

>From tglx's version: to be on the safe side, move the cacheinfo
descriptor check to free_cache_attributes(), thus cleaning up the
hotplug path a little and making this even more robust.

Reported-and-tested-by: Philip Müller <philm@manjaro.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: <stable@vger.kernel.org> # 4.1
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: manjaro-dev@manjaro.org
Cc: Philip Müller <philm@manjaro.org>
Link: https://lkml.kernel.org/r/55B47BB8.6080202@manjaro.org
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-09-17 06:06:54 -07:00

555 lines
14 KiB
C

/*
* cacheinfo support - processor cache information via sysfs
*
* Based on arch/x86/kernel/cpu/intel_cacheinfo.c
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#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/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)
struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
{
return ci_cacheinfo(cpu);
}
#ifdef CONFIG_OF
static int cache_setup_of_node(unsigned int cpu)
{
struct device_node *np;
struct cacheinfo *this_leaf;
struct device *cpu_dev = get_cpu_device(cpu);
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
unsigned int index = 0;
/* skip if of_node is already populated */
if (this_cpu_ci->info_list->of_node)
return 0;
if (!cpu_dev) {
pr_err("No cpu device for CPU %d\n", cpu);
return -ENODEV;
}
np = cpu_dev->of_node;
if (!np) {
pr_err("Failed to find cpu%d device node\n", cpu);
return -ENOENT;
}
while (index < cache_leaves(cpu)) {
this_leaf = this_cpu_ci->info_list + index;
if (this_leaf->level != 1)
np = of_find_next_cache_node(np);
else
np = of_node_get(np);/* cpu node itself */
if (!np)
break;
this_leaf->of_node = np;
index++;
}
if (index != cache_leaves(cpu)) /* not all OF nodes populated */
return -ENOENT;
return 0;
}
static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
struct cacheinfo *sib_leaf)
{
return sib_leaf->of_node == this_leaf->of_node;
}
#else
static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
struct cacheinfo *sib_leaf)
{
/*
* For non-DT systems, assume unique level 1 cache, system-wide
* shared caches for all other levels. This will be used only if
* arch specific code has not populated shared_cpu_map
*/
return !(this_leaf->level == 1);
}
#endif
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;
int ret;
ret = cache_setup_of_node(cpu);
if (ret)
return ret;
for (index = 0; index < cache_leaves(cpu); index++) {
unsigned int i;
this_leaf = this_cpu_ci->info_list + index;
/* skip if shared_cpu_map is already populated */
if (!cpumask_empty(&this_leaf->shared_cpu_map))
continue;
cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
for_each_online_cpu(i) {
struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
if (i == cpu || !sib_cpu_ci->info_list)
continue;/* skip if itself or no cacheinfo */
sib_leaf = sib_cpu_ci->info_list + index;
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);
}
}
}
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;
for (index = 0; index < cache_leaves(cpu); index++) {
this_leaf = this_cpu_ci->info_list + index;
for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
struct cpu_cacheinfo *sib_cpu_ci;
if (sibling == cpu) /* skip itself */
continue;
sib_cpu_ci = get_cpu_cacheinfo(sibling);
if (!sib_cpu_ci->info_list)
continue;
sib_leaf = sib_cpu_ci->info_list + index;
cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
}
of_node_put(this_leaf->of_node);
}
}
static void free_cache_attributes(unsigned int cpu)
{
if (!per_cpu_cacheinfo(cpu))
return;
cache_shared_cpu_map_remove(cpu);
kfree(per_cpu_cacheinfo(cpu));
per_cpu_cacheinfo(cpu) = NULL;
}
int __weak init_cache_level(unsigned int cpu)
{
return -ENOENT;
}
int __weak populate_cache_leaves(unsigned int cpu)
{
return -ENOENT;
}
static int detect_cache_attributes(unsigned int cpu)
{
int ret;
if (init_cache_level(cpu) || !cache_leaves(cpu))
return -ENOENT;
per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
sizeof(struct cacheinfo), GFP_KERNEL);
if (per_cpu_cacheinfo(cpu) == NULL)
return -ENOMEM;
ret = populate_cache_leaves(cpu);
if (ret)
goto free_ci;
/*
* For systems using DT for cache hierarchy, of_node 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 from DT 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 sprintf(buf, "%u\n", this_leaf->object); \
}
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 sprintf(buf, "%uK\n", this_leaf->size >> 10);
}
static ssize_t shared_cpumap_show_func(struct device *dev, bool list, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
const struct cpumask *mask = &this_leaf->shared_cpu_map;
return cpumap_print_to_pagebuf(list, buf, mask);
}
static ssize_t shared_cpu_map_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return shared_cpumap_show_func(dev, false, buf);
}
static ssize_t shared_cpu_list_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return shared_cpumap_show_func(dev, true, buf);
}
static ssize_t type_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cacheinfo *this_leaf = dev_get_drvdata(dev);
switch (this_leaf->type) {
case CACHE_TYPE_DATA:
return sprintf(buf, "Data\n");
case CACHE_TYPE_INST:
return sprintf(buf, "Instruction\n");
case CACHE_TYPE_UNIFIED:
return sprintf(buf, "Unified\n");
default:
return -EINVAL;
}
}
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;
int n = 0;
if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
n = sprintf(buf, "ReadWriteAllocate\n");
else if (ci_attr & CACHE_READ_ALLOCATE)
n = sprintf(buf, "ReadAllocate\n");
else if (ci_attr & CACHE_WRITE_ALLOCATE)
n = sprintf(buf, "WriteAllocate\n");
return n;
}
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 = sprintf(buf, "WriteThrough\n");
else if (ci_attr & CACHE_WRITE_BACK)
n = sprintf(buf, "WriteBack\n");
return n;
}
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_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_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) = kcalloc(cache_leaves(cpu),
sizeof(struct device *), GFP_KERNEL);
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;
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
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 = this_cpu_ci->info_list + i;
if (this_leaf->disable_sysfs)
continue;
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 void cache_remove_dev(unsigned int cpu)
{
if (!cpumask_test_cpu(cpu, &cache_dev_map))
return;
cpumask_clear_cpu(cpu, &cache_dev_map);
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 & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
rc = detect_cache_attributes(cpu);
if (!rc)
rc = cache_add_dev(cpu);
break;
case CPU_DEAD:
cache_remove_dev(cpu);
free_cache_attributes(cpu);
break;
}
return notifier_from_errno(rc);
}
static int __init cacheinfo_sysfs_init(void)
{
int cpu, rc = 0;
cpu_notifier_register_begin();
for_each_online_cpu(cpu) {
rc = detect_cache_attributes(cpu);
if (rc)
goto out;
rc = cache_add_dev(cpu);
if (rc) {
free_cache_attributes(cpu);
pr_err("error populating cacheinfo..cpu%d\n", cpu);
goto out;
}
}
__hotcpu_notifier(cacheinfo_cpu_callback, 0);
out:
cpu_notifier_register_done();
return rc;
}
device_initcall(cacheinfo_sysfs_init);