v4.19.13 snapshot.
diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c
new file mode 100644
index 0000000..3fd07e2
--- /dev/null
+++ b/drivers/hwtracing/stm/policy.c
@@ -0,0 +1,476 @@
+// 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);
+}