blob: 3fd07e275b34e9a8470e8203445cfc3c7a4cc19d [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* System Trace Module (STM) master/channel allocation policy management
* Copyright (c) 2014, Intel Corporation.
*
* A master/channel allocation policy allows mapping string identifiers to
* master and channel ranges, where allocation can be done.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/configfs.h>
#include <linux/slab.h>
#include <linux/stm.h>
#include "stm.h"
/*
* STP Master/Channel allocation policy configfs layout.
*/
struct stp_policy {
struct config_group group;
struct stm_device *stm;
};
struct stp_policy_node {
struct config_group group;
struct stp_policy *policy;
unsigned int first_master;
unsigned int last_master;
unsigned int first_channel;
unsigned int last_channel;
};
static struct configfs_subsystem stp_policy_subsys;
void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
unsigned int *mstart, unsigned int *mend,
unsigned int *cstart, unsigned int *cend)
{
*mstart = policy_node->first_master;
*mend = policy_node->last_master;
*cstart = policy_node->first_channel;
*cend = policy_node->last_channel;
}
static inline char *stp_policy_node_name(struct stp_policy_node *policy_node)
{
return policy_node->group.cg_item.ci_name ? : "<none>";
}
static inline struct stp_policy *to_stp_policy(struct config_item *item)
{
return item ?
container_of(to_config_group(item), struct stp_policy, group) :
NULL;
}
static inline struct stp_policy_node *
to_stp_policy_node(struct config_item *item)
{
return item ?
container_of(to_config_group(item), struct stp_policy_node,
group) :
NULL;
}
static ssize_t
stp_policy_node_masters_show(struct config_item *item, char *page)
{
struct stp_policy_node *policy_node = to_stp_policy_node(item);
ssize_t count;
count = sprintf(page, "%u %u\n", policy_node->first_master,
policy_node->last_master);
return count;
}
static ssize_t
stp_policy_node_masters_store(struct config_item *item, const char *page,
size_t count)
{
struct stp_policy_node *policy_node = to_stp_policy_node(item);
unsigned int first, last;
struct stm_device *stm;
char *p = (char *)page;
ssize_t ret = -ENODEV;
if (sscanf(p, "%u %u", &first, &last) != 2)
return -EINVAL;
mutex_lock(&stp_policy_subsys.su_mutex);
stm = policy_node->policy->stm;
if (!stm)
goto unlock;
/* must be within [sw_start..sw_end], which is an inclusive range */
if (first > last || first < stm->data->sw_start ||
last > stm->data->sw_end) {
ret = -ERANGE;
goto unlock;
}
ret = count;
policy_node->first_master = first;
policy_node->last_master = last;
unlock:
mutex_unlock(&stp_policy_subsys.su_mutex);
return ret;
}
static ssize_t
stp_policy_node_channels_show(struct config_item *item, char *page)
{
struct stp_policy_node *policy_node = to_stp_policy_node(item);
ssize_t count;
count = sprintf(page, "%u %u\n", policy_node->first_channel,
policy_node->last_channel);
return count;
}
static ssize_t
stp_policy_node_channels_store(struct config_item *item, const char *page,
size_t count)
{
struct stp_policy_node *policy_node = to_stp_policy_node(item);
unsigned int first, last;
struct stm_device *stm;
char *p = (char *)page;
ssize_t ret = -ENODEV;
if (sscanf(p, "%u %u", &first, &last) != 2)
return -EINVAL;
mutex_lock(&stp_policy_subsys.su_mutex);
stm = policy_node->policy->stm;
if (!stm)
goto unlock;
if (first > INT_MAX || last > INT_MAX || first > last ||
last >= stm->data->sw_nchannels) {
ret = -ERANGE;
goto unlock;
}
ret = count;
policy_node->first_channel = first;
policy_node->last_channel = last;
unlock:
mutex_unlock(&stp_policy_subsys.su_mutex);
return ret;
}
static void stp_policy_node_release(struct config_item *item)
{
kfree(to_stp_policy_node(item));
}
static struct configfs_item_operations stp_policy_node_item_ops = {
.release = stp_policy_node_release,
};
CONFIGFS_ATTR(stp_policy_node_, masters);
CONFIGFS_ATTR(stp_policy_node_, channels);
static struct configfs_attribute *stp_policy_node_attrs[] = {
&stp_policy_node_attr_masters,
&stp_policy_node_attr_channels,
NULL,
};
static const struct config_item_type stp_policy_type;
static const struct config_item_type stp_policy_node_type;
static struct config_group *
stp_policy_node_make(struct config_group *group, const char *name)
{
struct stp_policy_node *policy_node, *parent_node;
struct stp_policy *policy;
if (group->cg_item.ci_type == &stp_policy_type) {
policy = container_of(group, struct stp_policy, group);
} else {
parent_node = container_of(group, struct stp_policy_node,
group);
policy = parent_node->policy;
}
if (!policy->stm)
return ERR_PTR(-ENODEV);
policy_node = kzalloc(sizeof(struct stp_policy_node), GFP_KERNEL);
if (!policy_node)
return ERR_PTR(-ENOMEM);
config_group_init_type_name(&policy_node->group, name,
&stp_policy_node_type);
policy_node->policy = policy;
/* default values for the attributes */
policy_node->first_master = policy->stm->data->sw_start;
policy_node->last_master = policy->stm->data->sw_end;
policy_node->first_channel = 0;
policy_node->last_channel = policy->stm->data->sw_nchannels - 1;
return &policy_node->group;
}
static void
stp_policy_node_drop(struct config_group *group, struct config_item *item)
{
config_item_put(item);
}
static struct configfs_group_operations stp_policy_node_group_ops = {
.make_group = stp_policy_node_make,
.drop_item = stp_policy_node_drop,
};
static const struct config_item_type stp_policy_node_type = {
.ct_item_ops = &stp_policy_node_item_ops,
.ct_group_ops = &stp_policy_node_group_ops,
.ct_attrs = stp_policy_node_attrs,
.ct_owner = THIS_MODULE,
};
/*
* Root group: policies.
*/
static ssize_t stp_policy_device_show(struct config_item *item,
char *page)
{
struct stp_policy *policy = to_stp_policy(item);
ssize_t count;
count = sprintf(page, "%s\n",
(policy && policy->stm) ?
policy->stm->data->name :
"<none>");
return count;
}
CONFIGFS_ATTR_RO(stp_policy_, device);
static struct configfs_attribute *stp_policy_attrs[] = {
&stp_policy_attr_device,
NULL,
};
void stp_policy_unbind(struct stp_policy *policy)
{
struct stm_device *stm = policy->stm;
/*
* stp_policy_release() will not call here if the policy is already
* unbound; other users should not either, as no link exists between
* this policy and anything else in that case
*/
if (WARN_ON_ONCE(!policy->stm))
return;
lockdep_assert_held(&stm->policy_mutex);
stm->policy = NULL;
policy->stm = NULL;
stm_put_device(stm);
}
static void stp_policy_release(struct config_item *item)
{
struct stp_policy *policy = to_stp_policy(item);
struct stm_device *stm = policy->stm;
/* a policy *can* be unbound and still exist in configfs tree */
if (!stm)
return;
mutex_lock(&stm->policy_mutex);
stp_policy_unbind(policy);
mutex_unlock(&stm->policy_mutex);
kfree(policy);
}
static struct configfs_item_operations stp_policy_item_ops = {
.release = stp_policy_release,
};
static struct configfs_group_operations stp_policy_group_ops = {
.make_group = stp_policy_node_make,
};
static const struct config_item_type stp_policy_type = {
.ct_item_ops = &stp_policy_item_ops,
.ct_group_ops = &stp_policy_group_ops,
.ct_attrs = stp_policy_attrs,
.ct_owner = THIS_MODULE,
};
static struct config_group *
stp_policies_make(struct config_group *group, const char *name)
{
struct config_group *ret;
struct stm_device *stm;
char *devname, *p;
devname = kasprintf(GFP_KERNEL, "%s", name);
if (!devname)
return ERR_PTR(-ENOMEM);
/*
* node must look like <device_name>.<policy_name>, where
* <device_name> is the name of an existing stm device; may
* contain dots;
* <policy_name> is an arbitrary string; may not contain dots
*/
p = strrchr(devname, '.');
if (!p) {
kfree(devname);
return ERR_PTR(-EINVAL);
}
*p = '\0';
stm = stm_find_device(devname);
kfree(devname);
if (!stm)
return ERR_PTR(-ENODEV);
mutex_lock(&stm->policy_mutex);
if (stm->policy) {
ret = ERR_PTR(-EBUSY);
goto unlock_policy;
}
stm->policy = kzalloc(sizeof(*stm->policy), GFP_KERNEL);
if (!stm->policy) {
ret = ERR_PTR(-ENOMEM);
goto unlock_policy;
}
config_group_init_type_name(&stm->policy->group, name,
&stp_policy_type);
stm->policy->stm = stm;
ret = &stm->policy->group;
unlock_policy:
mutex_unlock(&stm->policy_mutex);
if (IS_ERR(ret))
stm_put_device(stm);
return ret;
}
static struct configfs_group_operations stp_policies_group_ops = {
.make_group = stp_policies_make,
};
static const struct config_item_type stp_policies_type = {
.ct_group_ops = &stp_policies_group_ops,
.ct_owner = THIS_MODULE,
};
static struct configfs_subsystem stp_policy_subsys = {
.su_group = {
.cg_item = {
.ci_namebuf = "stp-policy",
.ci_type = &stp_policies_type,
},
},
};
/*
* Lock the policy mutex from the outside
*/
static struct stp_policy_node *
__stp_policy_node_lookup(struct stp_policy *policy, char *s)
{
struct stp_policy_node *policy_node, *ret;
struct list_head *head = &policy->group.cg_children;
struct config_item *item;
char *start, *end = s;
if (list_empty(head))
return NULL;
/* return the first entry if everything else fails */
item = list_entry(head->next, struct config_item, ci_entry);
ret = to_stp_policy_node(item);
next:
for (;;) {
start = strsep(&end, "/");
if (!start)
break;
if (!*start)
continue;
list_for_each_entry(item, head, ci_entry) {
policy_node = to_stp_policy_node(item);
if (!strcmp(start,
policy_node->group.cg_item.ci_name)) {
ret = policy_node;
if (!end)
goto out;
head = &policy_node->group.cg_children;
goto next;
}
}
break;
}
out:
return ret;
}
struct stp_policy_node *
stp_policy_node_lookup(struct stm_device *stm, char *s)
{
struct stp_policy_node *policy_node = NULL;
mutex_lock(&stp_policy_subsys.su_mutex);
mutex_lock(&stm->policy_mutex);
if (stm->policy)
policy_node = __stp_policy_node_lookup(stm->policy, s);
mutex_unlock(&stm->policy_mutex);
if (policy_node)
config_item_get(&policy_node->group.cg_item);
mutex_unlock(&stp_policy_subsys.su_mutex);
return policy_node;
}
void stp_policy_node_put(struct stp_policy_node *policy_node)
{
config_item_put(&policy_node->group.cg_item);
}
int __init stp_configfs_init(void)
{
int err;
config_group_init(&stp_policy_subsys.su_group);
mutex_init(&stp_policy_subsys.su_mutex);
err = configfs_register_subsystem(&stp_policy_subsys);
return err;
}
void __exit stp_configfs_exit(void)
{
configfs_unregister_subsystem(&stp_policy_subsys);
}