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linux-next/arch/ia64/kernel/topology.c
Srivatsa S. Bhat f5a7d445ff ia64, topology: Fix CPU hotplug callback registration
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	/* Note the use of the double underscored version of the API */
	__register_cpu_notifier(&foobar_cpu_notifier);

	cpu_notifier_register_done();

Fix the topology code in ia64 by using this latter form of callback
registration.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-20 13:43:40 +01:00

473 lines
11 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* This file contains NUMA specific variables and functions which can
* be split away from DISCONTIGMEM and are used on NUMA machines with
* contiguous memory.
* 2002/08/07 Erich Focht <efocht@ess.nec.de>
* Populate cpu entries in sysfs for non-numa systems as well
* Intel Corporation - Ashok Raj
* 02/27/2006 Zhang, Yanmin
* Populate cpu cache entries in sysfs for cpu cache info
*/
#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/node.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/nodemask.h>
#include <linux/notifier.h>
#include <linux/export.h>
#include <asm/mmzone.h>
#include <asm/numa.h>
#include <asm/cpu.h>
static struct ia64_cpu *sysfs_cpus;
void arch_fix_phys_package_id(int num, u32 slot)
{
#ifdef CONFIG_SMP
if (cpu_data(num)->socket_id == -1)
cpu_data(num)->socket_id = slot;
#endif
}
EXPORT_SYMBOL_GPL(arch_fix_phys_package_id);
#ifdef CONFIG_HOTPLUG_CPU
int __ref arch_register_cpu(int num)
{
#ifdef CONFIG_ACPI
/*
* If CPEI can be re-targeted or if this is not
* CPEI target, then it is hotpluggable
*/
if (can_cpei_retarget() || !is_cpu_cpei_target(num))
sysfs_cpus[num].cpu.hotpluggable = 1;
map_cpu_to_node(num, node_cpuid[num].nid);
#endif
return register_cpu(&sysfs_cpus[num].cpu, num);
}
EXPORT_SYMBOL(arch_register_cpu);
void __ref arch_unregister_cpu(int num)
{
unregister_cpu(&sysfs_cpus[num].cpu);
#ifdef CONFIG_ACPI
unmap_cpu_from_node(num, cpu_to_node(num));
#endif
}
EXPORT_SYMBOL(arch_unregister_cpu);
#else
static int __init arch_register_cpu(int num)
{
return register_cpu(&sysfs_cpus[num].cpu, num);
}
#endif /*CONFIG_HOTPLUG_CPU*/
static int __init topology_init(void)
{
int i, err = 0;
#ifdef CONFIG_NUMA
/*
* MCD - Do we want to register all ONLINE nodes, or all POSSIBLE nodes?
*/
for_each_online_node(i) {
if ((err = register_one_node(i)))
goto out;
}
#endif
sysfs_cpus = kzalloc(sizeof(struct ia64_cpu) * NR_CPUS, GFP_KERNEL);
if (!sysfs_cpus)
panic("kzalloc in topology_init failed - NR_CPUS too big?");
for_each_present_cpu(i) {
if((err = arch_register_cpu(i)))
goto out;
}
out:
return err;
}
subsys_initcall(topology_init);
/*
* Export cpu cache information through sysfs
*/
/*
* A bunch of string array to get pretty printing
*/
static const char *cache_types[] = {
"", /* not used */
"Instruction",
"Data",
"Unified" /* unified */
};
static const char *cache_mattrib[]={
"WriteThrough",
"WriteBack",
"", /* reserved */
"" /* reserved */
};
struct cache_info {
pal_cache_config_info_t cci;
cpumask_t shared_cpu_map;
int level;
int type;
struct kobject kobj;
};
struct cpu_cache_info {
struct cache_info *cache_leaves;
int num_cache_leaves;
struct kobject kobj;
};
static struct cpu_cache_info all_cpu_cache_info[NR_CPUS];
#define LEAF_KOBJECT_PTR(x,y) (&all_cpu_cache_info[x].cache_leaves[y])
#ifdef CONFIG_SMP
static void cache_shared_cpu_map_setup(unsigned int cpu,
struct cache_info * this_leaf)
{
pal_cache_shared_info_t csi;
int num_shared, i = 0;
unsigned int j;
if (cpu_data(cpu)->threads_per_core <= 1 &&
cpu_data(cpu)->cores_per_socket <= 1) {
cpu_set(cpu, this_leaf->shared_cpu_map);
return;
}
if (ia64_pal_cache_shared_info(this_leaf->level,
this_leaf->type,
0,
&csi) != PAL_STATUS_SUCCESS)
return;
num_shared = (int) csi.num_shared;
do {
for_each_possible_cpu(j)
if (cpu_data(cpu)->socket_id == cpu_data(j)->socket_id
&& cpu_data(j)->core_id == csi.log1_cid
&& cpu_data(j)->thread_id == csi.log1_tid)
cpu_set(j, this_leaf->shared_cpu_map);
i++;
} while (i < num_shared &&
ia64_pal_cache_shared_info(this_leaf->level,
this_leaf->type,
i,
&csi) == PAL_STATUS_SUCCESS);
}
#else
static void cache_shared_cpu_map_setup(unsigned int cpu,
struct cache_info * this_leaf)
{
cpu_set(cpu, this_leaf->shared_cpu_map);
return;
}
#endif
static ssize_t show_coherency_line_size(struct cache_info *this_leaf,
char *buf)
{
return sprintf(buf, "%u\n", 1 << this_leaf->cci.pcci_line_size);
}
static ssize_t show_ways_of_associativity(struct cache_info *this_leaf,
char *buf)
{
return sprintf(buf, "%u\n", this_leaf->cci.pcci_assoc);
}
static ssize_t show_attributes(struct cache_info *this_leaf, char *buf)
{
return sprintf(buf,
"%s\n",
cache_mattrib[this_leaf->cci.pcci_cache_attr]);
}
static ssize_t show_size(struct cache_info *this_leaf, char *buf)
{
return sprintf(buf, "%uK\n", this_leaf->cci.pcci_cache_size / 1024);
}
static ssize_t show_number_of_sets(struct cache_info *this_leaf, char *buf)
{
unsigned number_of_sets = this_leaf->cci.pcci_cache_size;
number_of_sets /= this_leaf->cci.pcci_assoc;
number_of_sets /= 1 << this_leaf->cci.pcci_line_size;
return sprintf(buf, "%u\n", number_of_sets);
}
static ssize_t show_shared_cpu_map(struct cache_info *this_leaf, char *buf)
{
ssize_t len;
cpumask_t shared_cpu_map;
cpumask_and(&shared_cpu_map,
&this_leaf->shared_cpu_map, cpu_online_mask);
len = cpumask_scnprintf(buf, NR_CPUS+1, &shared_cpu_map);
len += sprintf(buf+len, "\n");
return len;
}
static ssize_t show_type(struct cache_info *this_leaf, char *buf)
{
int type = this_leaf->type + this_leaf->cci.pcci_unified;
return sprintf(buf, "%s\n", cache_types[type]);
}
static ssize_t show_level(struct cache_info *this_leaf, char *buf)
{
return sprintf(buf, "%u\n", this_leaf->level);
}
struct cache_attr {
struct attribute attr;
ssize_t (*show)(struct cache_info *, char *);
ssize_t (*store)(struct cache_info *, const char *, size_t count);
};
#ifdef define_one_ro
#undef define_one_ro
#endif
#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(size);
define_one_ro(number_of_sets);
define_one_ro(shared_cpu_map);
define_one_ro(attributes);
static struct attribute * cache_default_attrs[] = {
&type.attr,
&level.attr,
&coherency_line_size.attr,
&ways_of_associativity.attr,
&attributes.attr,
&size.attr,
&number_of_sets.attr,
&shared_cpu_map.attr,
NULL
};
#define to_object(k) container_of(k, struct cache_info, kobj)
#define to_attr(a) container_of(a, struct cache_attr, attr)
static ssize_t ia64_cache_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
struct cache_attr *fattr = to_attr(attr);
struct cache_info *this_leaf = to_object(kobj);
ssize_t ret;
ret = fattr->show ? fattr->show(this_leaf, buf) : 0;
return ret;
}
static const struct sysfs_ops cache_sysfs_ops = {
.show = ia64_cache_show
};
static struct kobj_type cache_ktype = {
.sysfs_ops = &cache_sysfs_ops,
.default_attrs = cache_default_attrs,
};
static struct kobj_type cache_ktype_percpu_entry = {
.sysfs_ops = &cache_sysfs_ops,
};
static void cpu_cache_sysfs_exit(unsigned int cpu)
{
kfree(all_cpu_cache_info[cpu].cache_leaves);
all_cpu_cache_info[cpu].cache_leaves = NULL;
all_cpu_cache_info[cpu].num_cache_leaves = 0;
memset(&all_cpu_cache_info[cpu].kobj, 0, sizeof(struct kobject));
return;
}
static int cpu_cache_sysfs_init(unsigned int cpu)
{
unsigned long i, levels, unique_caches;
pal_cache_config_info_t cci;
int j;
long status;
struct cache_info *this_cache;
int num_cache_leaves = 0;
if ((status = ia64_pal_cache_summary(&levels, &unique_caches)) != 0) {
printk(KERN_ERR "ia64_pal_cache_summary=%ld\n", status);
return -1;
}
this_cache=kzalloc(sizeof(struct cache_info)*unique_caches,
GFP_KERNEL);
if (this_cache == NULL)
return -ENOMEM;
for (i=0; i < levels; i++) {
for (j=2; j >0 ; j--) {
if ((status=ia64_pal_cache_config_info(i,j, &cci)) !=
PAL_STATUS_SUCCESS)
continue;
this_cache[num_cache_leaves].cci = cci;
this_cache[num_cache_leaves].level = i + 1;
this_cache[num_cache_leaves].type = j;
cache_shared_cpu_map_setup(cpu,
&this_cache[num_cache_leaves]);
num_cache_leaves ++;
}
}
all_cpu_cache_info[cpu].cache_leaves = this_cache;
all_cpu_cache_info[cpu].num_cache_leaves = num_cache_leaves;
memset(&all_cpu_cache_info[cpu].kobj, 0, sizeof(struct kobject));
return 0;
}
/* Add cache interface for CPU device */
static int cache_add_dev(struct device *sys_dev)
{
unsigned int cpu = sys_dev->id;
unsigned long i, j;
struct cache_info *this_object;
int retval = 0;
cpumask_t oldmask;
if (all_cpu_cache_info[cpu].kobj.parent)
return 0;
oldmask = current->cpus_allowed;
retval = set_cpus_allowed_ptr(current, cpumask_of(cpu));
if (unlikely(retval))
return retval;
retval = cpu_cache_sysfs_init(cpu);
set_cpus_allowed_ptr(current, &oldmask);
if (unlikely(retval < 0))
return retval;
retval = kobject_init_and_add(&all_cpu_cache_info[cpu].kobj,
&cache_ktype_percpu_entry, &sys_dev->kobj,
"%s", "cache");
if (unlikely(retval < 0)) {
cpu_cache_sysfs_exit(cpu);
return retval;
}
for (i = 0; i < all_cpu_cache_info[cpu].num_cache_leaves; i++) {
this_object = LEAF_KOBJECT_PTR(cpu,i);
retval = kobject_init_and_add(&(this_object->kobj),
&cache_ktype,
&all_cpu_cache_info[cpu].kobj,
"index%1lu", i);
if (unlikely(retval)) {
for (j = 0; j < i; j++) {
kobject_put(&(LEAF_KOBJECT_PTR(cpu,j)->kobj));
}
kobject_put(&all_cpu_cache_info[cpu].kobj);
cpu_cache_sysfs_exit(cpu);
return retval;
}
kobject_uevent(&(this_object->kobj), KOBJ_ADD);
}
kobject_uevent(&all_cpu_cache_info[cpu].kobj, KOBJ_ADD);
return retval;
}
/* Remove cache interface for CPU device */
static int cache_remove_dev(struct device *sys_dev)
{
unsigned int cpu = sys_dev->id;
unsigned long i;
for (i = 0; i < all_cpu_cache_info[cpu].num_cache_leaves; i++)
kobject_put(&(LEAF_KOBJECT_PTR(cpu,i)->kobj));
if (all_cpu_cache_info[cpu].kobj.parent) {
kobject_put(&all_cpu_cache_info[cpu].kobj);
memset(&all_cpu_cache_info[cpu].kobj,
0,
sizeof(struct kobject));
}
cpu_cache_sysfs_exit(cpu);
return 0;
}
/*
* When a cpu is hot-plugged, do a check and initiate
* cache kobject if necessary
*/
static int cache_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
struct device *sys_dev;
sys_dev = get_cpu_device(cpu);
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
cache_add_dev(sys_dev);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
cache_remove_dev(sys_dev);
break;
}
return NOTIFY_OK;
}
static struct notifier_block cache_cpu_notifier =
{
.notifier_call = cache_cpu_callback
};
static int __init cache_sysfs_init(void)
{
int i;
cpu_notifier_register_begin();
for_each_online_cpu(i) {
struct device *sys_dev = get_cpu_device((unsigned int)i);
cache_add_dev(sys_dev);
}
__register_hotcpu_notifier(&cache_cpu_notifier);
cpu_notifier_register_done();
return 0;
}
device_initcall(cache_sysfs_init);