/*
* User interface for Resource Alloction in Resource Director Technology(RDT)
*
* Copyright (C) 2016 Intel Corporation
*
* Author: Fenghua Yu <fenghua.yu@intel.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* More information about RDT be found in the Intel (R) x86 Architecture
* Software Developer Manual.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpu.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/kernfs.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/task_work.h>
#include <uapi/linux/magic.h>
#include <asm/intel_rdt.h>
#include <asm/intel_rdt_common.h>
DEFINE_STATIC_KEY_FALSE(rdt_enable_key);
struct kernfs_root *rdt_root;
struct rdtgroup rdtgroup_default;
LIST_HEAD(rdt_all_groups);
/* Kernel fs node for "info" directory under root */
static struct kernfs_node *kn_info;
/*
* Trivial allocator for CLOSIDs. Since h/w only supports a small number,
* we can keep a bitmap of free CLOSIDs in a single integer.
*
* Using a global CLOSID across all resources has some advantages and
* some drawbacks:
* + We can simply set "current->closid" to assign a task to a resource
* group.
* + Context switch code can avoid extra memory references deciding which
* CLOSID to load into the PQR_ASSOC MSR
* - We give up some options in configuring resource groups across multi-socket
* systems.
* - Our choices on how to configure each resource become progressively more
* limited as the number of resources grows.
*/
static int closid_free_map;
static void closid_init(void)
{
struct rdt_resource *r;
int rdt_min_closid = 32;
/* Compute rdt_min_closid across all resources */
for_each_enabled_rdt_resource(r)
rdt_min_closid = min(rdt_min_closid, r->num_closid);
closid_free_map = BIT_MASK(rdt_min_closid) - 1;
/* CLOSID 0 is always reserved for the default group */
closid_free_map &= ~1;
}
int closid_alloc(void)
{
int closid = ffs(closid_free_map);
if (closid == 0)
return -ENOSPC;
closid--;
closid_free_map &= ~(1 << closid);
return closid;
}
static void closid_free(int closid)
{
closid_free_map |= 1 << closid;
}
/* set uid and gid of rdtgroup dirs and files to that of the creator */
static int rdtgroup_kn_set_ugid(struct kernfs_node *kn)
{
struct iattr iattr = { .ia_valid = ATTR_UID | ATTR_GID,
.ia_uid = current_fsuid(),
.ia_gid = current_fsgid(), };
if (uid_eq(iattr.ia_uid, GLOBAL_ROOT_UID) &&
gid_eq(iattr.ia_gid, GLOBAL_ROOT_GID))
return 0;
return kernfs_setattr(kn, &iattr);
}
static int rdtgroup_add_file(struct kernfs_node *parent_kn, struct rftype *rft)
{
struct kernfs_node *kn;
int ret;
kn = __kernfs_create_file(parent_kn, rft->name, rft->mode,
0, rft->kf_ops, rft, NULL, NULL);
if (IS_ERR(kn))
return PTR_ERR(kn);
ret = rdtgroup_kn_set_ugid(kn);
if (ret) {
kernfs_remove(kn);
return ret;
}
return 0;
}
static int rdtgroup_add_files(struct kernfs_node *kn, struct rftype *rfts,
int len)
{
struct rftype *rft;
int ret;
lockdep_assert_held(&rdtgroup_mutex);
for (rft = rfts; rft < rfts + len; rft++) {
ret = rdtgroup_add_file(kn, rft);
if (ret)
goto error;
}
return 0;
error:
pr_warn("Failed to add %s, err=%d\n", rft->name, ret);
while (--rft >= rfts)
kernfs_remove_by_name(kn, rft->name);
return ret;
}
static int rdtgroup_seqfile_show(struct seq_file *m, void *arg)
{
struct kernfs_open_file *of = m->private;
struct rftype *rft = of->kn->priv;
if (rft->seq_show)
return rft->seq_show(of, m, arg);
return 0;
}
static ssize_t rdtgroup_file_write(struct kernfs_open_file *of, char *buf,
size_t nbytes, loff_t off)
{
struct rftype *rft = of->kn->priv;
if (rft->write)
return rft->write(of, buf, nbytes, off);
return -EINVAL;
}
static struct kernfs_ops rdtgroup_kf_single_ops = {
.atomic_write_len = PAGE_SIZE,
.write = rdtgroup_file_write,
.seq_show = rdtgroup_seqfile_show,
};
static int rdtgroup_cpus_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct rdtgroup *rdtgrp;
int ret = 0;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (rdtgrp)
seq_printf(s, "%*pb\n", cpumask_pr_args(&rdtgrp->cpu_mask));
else
ret = -ENOENT;
rdtgroup_kn_unlock(of->kn);
return ret;
}
/*
* This is safe against intel_rdt_sched_in() called from __switch_to()
* because __switch_to() is executed with interrupts disabled. A local call
* from rdt_update_closid() is proteced against __switch_to() because
* preemption is disabled.
*/
static void rdt_update_cpu_closid(void *closid)
{
if (closid)
this_cpu_write(cpu_closid, *(int *)closid);
/*
* We cannot unconditionally write the MSR because the current
* executing task might have its own closid selected. Just reuse
* the context switch code.
*/
intel_rdt_sched_in();
}
/*
* Update the PGR_ASSOC MSR on all cpus in @cpu_mask,
*
* Per task closids must have been set up before calling this function.
*
* The per cpu closids are updated with the smp function call, when @closid
* is not NULL. If @closid is NULL then all affected percpu closids must
* have been set up before calling this function.
*/
static void
rdt_update_closid(const struct cpumask *cpu_mask, int *closid)
{
int cpu = get_cpu();
if (cpumask_test_cpu(cpu, cpu_mask))
rdt_update_cpu_closid(closid);
smp_call_function_many(cpu_mask, rdt_update_cpu_closid, closid, 1);
put_cpu();
}
static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
cpumask_var_t tmpmask, newmask;
struct rdtgroup *rdtgrp, *r;
int ret;
if (!buf)
return -EINVAL;
if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
return -ENOMEM;
if (!zalloc_cpumask_var(&newmask, GFP_KERNEL)) {
free_cpumask_var(tmpmask);
return -ENOMEM;
}
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
ret = -ENOENT;
goto unlock;
}
ret = cpumask_parse(buf, newmask);
if (ret)
goto unlock;
/* check that user didn't specify any offline cpus */
cpumask_andnot(tmpmask, newmask, cpu_online_mask);
if (cpumask_weight(tmpmask)) {
ret = -EINVAL;
goto unlock;
}
/* Check whether cpus are dropped from this group */
cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask);
if (cpumask_weight(tmpmask)) {
/* Can't drop from default group */
if (rdtgrp == &rdtgroup_default) {
ret = -EINVAL;
goto unlock;
}
/* Give any dropped cpus to rdtgroup_default */
cpumask_or(&rdtgroup_default.cpu_mask,
&rdtgroup_default.cpu_mask, tmpmask);
rdt_update_closid(tmpmask, &rdtgroup_default.closid);
}
/*
* If we added cpus, remove them from previous group that owned them
* and update per-cpu closid
*/
cpumask_andnot(tmpmask, newmask, &rdtgrp->cpu_mask);
if (cpumask_weight(tmpmask)) {
list_for_each_entry(r, &rdt_all_groups, rdtgroup_list) {
if (r == rdtgrp)
continue;
cpumask_andnot(&r->cpu_mask, &r->cpu_mask, tmpmask);
}
rdt_update_closid(tmpmask, &rdtgrp->closid);
}
/* Done pushing/pulling - update this group with new mask */
cpumask_copy(&rdtgrp->cpu_mask, newmask);
unlock:
rdtgroup_kn_unlock(of->kn);
free_cpumask_var(tmpmask);
free_cpumask_var(newmask);
return ret ?: nbytes;
}
struct task_move_callback {
struct callback_head work;
struct rdtgroup *rdtgrp;
};
static void move_myself(struct callback_head *head)
{
struct task_move_callback *callback;
struct rdtgroup *rdtgrp;
callback = container_of(head, struct task_move_callback, work);
rdtgrp = callback->rdtgrp;
/*
* If resource group was deleted before this task work callback
* was invoked, then assign the task to root group and free the
* resource group.
*/
if (atomic_dec_and_test(&rdtgrp->waitcount) &&
(rdtgrp->flags & RDT_DELETED)) {
current->closid = 0;
kfree(rdtgrp);
}
preempt_disable();
/* update PQR_ASSOC MSR to make resource group go into effect */
intel_rdt_sched_in();
preempt_enable();
kfree(callback);
}
static int __rdtgroup_move_task(struct task_struct *tsk,
struct rdtgroup *rdtgrp)
{
struct task_move_callback *callback;
int ret;
callback = kzalloc(sizeof(*callback), GFP_KERNEL);
if (!callback)
return -ENOMEM;
callback->work.func = move_myself;
callback->rdtgrp = rdtgrp;
/*
* Take a refcount, so rdtgrp cannot be freed before the
* callback has been invoked.
*/
atomic_inc(&rdtgrp->waitcount);
ret = task_work_add(tsk, &callback->work, true);
if (ret) {
/*
* Task is exiting. Drop the refcount and free the callback.
* No need to check the refcount as the group cannot be
* deleted before the write function unlocks rdtgroup_mutex.
*/
atomic_dec(&rdtgrp->waitcount);
kfree(callback);
} else {
tsk->closid = rdtgrp->closid;
}
return ret;
}
static int rdtgroup_task_write_permission(struct task_struct *task,
struct kernfs_open_file *of)
{
const struct cred *tcred = get_task_cred(task);
const struct cred *cred = current_cred();
int ret = 0;
/*
* Even if we're attaching all tasks in the thread group, we only
* need to check permissions on one of them.
*/
if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
!uid_eq(cred->euid, tcred->uid) &&
!uid_eq(cred->euid, tcred->suid))
ret = -EPERM;
put_cred(tcred);
return ret;
}
static int rdtgroup_move_task(pid_t pid, struct rdtgroup *rdtgrp,
struct kernfs_open_file *of)
{
struct task_struct *tsk;
int ret;
rcu_read_lock();
if (pid) {
tsk = find_task_by_vpid(pid);
if (!tsk) {
rcu_read_unlock();
return -ESRCH;
}
} else {
tsk = current;
}
get_task_struct(tsk);
rcu_read_unlock();
ret = rdtgroup_task_write_permission(tsk, of);
if (!ret)
ret = __rdtgroup_move_task(tsk, rdtgrp);
put_task_struct(tsk);
return ret;
}
static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct rdtgroup *rdtgrp;
int ret = 0;
pid_t pid;
if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
return -EINVAL;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (rdtgrp)
ret = rdtgroup_move_task(pid, rdtgrp, of);
else
ret = -ENOENT;
rdtgroup_kn_unlock(of->kn);
return ret ?: nbytes;
}
static void show_rdt_tasks(struct rdtgroup *r, struct seq_file *s)
{
struct task_struct *p, *t;
rcu_read_lock();
for_each_process_thread(p, t) {
if (t->closid == r->closid)
seq_printf(s, "%d\n", t->pid);
}
rcu_read_unlock();
}
static int rdtgroup_tasks_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct rdtgroup *rdtgrp;
int ret = 0;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (rdtgrp)
show_rdt_tasks(rdtgrp, s);
else
ret = -ENOENT;
rdtgroup_kn_unlock(of->kn);
return ret;
}
/* Files in each rdtgroup */
static struct rftype rdtgroup_base_files[] = {
{
.name = "cpus",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_cpus_write,
.seq_show = rdtgroup_cpus_show,
},
{
.name = "tasks",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_tasks_write,
.seq_show = rdtgroup_tasks_show,
},
{
.name = "schemata",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_schemata_write,
.seq_show = rdtgroup_schemata_show,
},
};
static int rdt_num_closids_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
seq_printf(seq, "%d\n", r->num_closid);
return 0;
}
static int rdt_cbm_mask_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
seq_printf(seq, "%x\n", r->max_cbm);
return 0;
}
static int rdt_min_cbm_bits_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
seq_printf(seq, "%d\n", r->min_cbm_bits);
return 0;
}
/* rdtgroup information files for one cache resource. */
static struct rftype res_info_files[] = {
{
.name = "num_closids",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_num_closids_show,
},
{
.name = "cbm_mask",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_cbm_mask_show,
},
{
.name = "min_cbm_bits",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_min_cbm_bits_show,
},
};
static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
{
struct kernfs_node *kn_subdir;
struct rdt_resource *r;
int ret;
/* create the directory */
kn_info = kernfs_create_dir(parent_kn, "info", parent_kn->mode, NULL);
if (IS_ERR(kn_info))
return PTR_ERR(kn_info);
kernfs_get(kn_info);
for_each_enabled_rdt_resource(r) {
kn_subdir = kernfs_create_dir(kn_info, r->name,
kn_info->mode, r);
if (IS_ERR(kn_subdir)) {
ret = PTR_ERR(kn_subdir);
goto out_destroy;
}
kernfs_get(kn_subdir);
ret = rdtgroup_kn_set_ugid(kn_subdir);
if (ret)
goto out_destroy;
ret = rdtgroup_add_files(kn_subdir, res_info_files,
ARRAY_SIZE(res_info_files));
if (ret)
goto out_destroy;
kernfs_activate(kn_subdir);
}
/*
* This extra ref will be put in kernfs_remove() and guarantees
* that @rdtgrp->kn is always accessible.
*/
kernfs_get(kn_info);
ret = rdtgroup_kn_set_ugid(kn_info);
if (ret)
goto out_destroy;
kernfs_activate(kn_info);
return 0;
out_destroy:
kernfs_remove(kn_info);
return ret;
}
static void l3_qos_cfg_update(void *arg)
{
bool *enable = arg;
wrmsrl(IA32_L3_QOS_CFG, *enable ? L3_QOS_CDP_ENABLE : 0ULL);
}
static int set_l3_qos_cfg(struct rdt_resource *r, bool enable)
{
cpumask_var_t cpu_mask;
struct rdt_domain *d;
int cpu;
if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
return -ENOMEM;
list_for_each_entry(d, &r->domains, list) {
/* Pick one CPU from each domain instance to update MSR */
cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
}
cpu = get_cpu();
/* Update QOS_CFG MSR on this cpu if it's in cpu_mask. */
if (cpumask_test_cpu(cpu, cpu_mask))
l3_qos_cfg_update(&enable);
/* Update QOS_CFG MSR on all other cpus in cpu_mask. */
smp_call_function_many(cpu_mask, l3_qos_cfg_update, &enable, 1);
put_cpu();
free_cpumask_var(cpu_mask);
return 0;
}
static int cdp_enable(void)
{
struct rdt_resource *r_l3data = &rdt_resources_all[RDT_RESOURCE_L3DATA];
struct rdt_resource *r_l3code = &rdt_resources_all[RDT_RESOURCE_L3CODE];
struct rdt_resource *r_l3 = &rdt_resources_all[RDT_RESOURCE_L3];
int ret;
if (!r_l3->capable || !r_l3data->capable || !r_l3code->capable)
return -EINVAL;
ret = set_l3_qos_cfg(r_l3, true);
if (!ret) {
r_l3->enabled = false;
r_l3data->enabled = true;
r_l3code->enabled = true;
}
return ret;
}
static void cdp_disable(void)
{
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3];
r->enabled = r->capable;
if (rdt_resources_all[RDT_RESOURCE_L3DATA].enabled) {
rdt_resources_all[RDT_RESOURCE_L3DATA].enabled = false;
rdt_resources_all[RDT_RESOURCE_L3CODE].enabled = false;
set_l3_qos_cfg(r, false);
}
}
static int parse_rdtgroupfs_options(char *data)
{
char *token, *o = data;
int ret = 0;
while ((token = strsep(&o, ",")) != NULL) {
if (!*token)
return -EINVAL;
if (!strcmp(token, "cdp"))
ret = cdp_enable();
}
return ret;
}
/*
* We don't allow rdtgroup directories to be created anywhere
* except the root directory. Thus when looking for the rdtgroup
* structure for a kernfs node we are either looking at a directory,
* in which case the rdtgroup structure is pointed at by the "priv"
* field, otherwise we have a file, and need only look to the parent
* to find the rdtgroup.
*/
static struct rdtgroup *kernfs_to_rdtgroup(struct kernfs_node *kn)
{
if (kernfs_type(kn) == KERNFS_DIR) {
/*
* All the resource directories use "kn->priv"
* to point to the "struct rdtgroup" for the
* resource. "info" and its subdirectories don't
* have rdtgroup structures, so return NULL here.
*/
if (kn == kn_info || kn->parent == kn_info)
return NULL;
else
return kn->priv;
} else {
return kn->parent->priv;
}
}
struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn)
{
struct rdtgroup *rdtgrp = kernfs_to_rdtgroup(kn);
if (!rdtgrp)
return NULL;
atomic_inc(&rdtgrp->waitcount);
kernfs_break_active_protection(kn);
mutex_lock(&rdtgroup_mutex);
/* Was this group deleted while we waited? */
if (rdtgrp->flags & RDT_DELETED)
return NULL;
return rdtgrp;
}
void rdtgroup_kn_unlock(struct kernfs_node *kn)
{
struct rdtgroup *rdtgrp = kernfs_to_rdtgroup(kn);
if (!rdtgrp)
return;
mutex_unlock(&rdtgroup_mutex);
if (atomic_dec_and_test(&rdtgrp->waitcount) &&
(rdtgrp->flags & RDT_DELETED)) {
kernfs_unbreak_active_protection(kn);
kernfs_put(kn);
kfree(rdtgrp);
} else {
kernfs_unbreak_active_protection(kn);
}
}
static struct dentry *rdt_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data)
{
struct dentry *dentry;
int ret;
mutex_lock(&rdtgroup_mutex);
/*
* resctrl file system can only be mounted once.
*/
if (static_branch_unlikely(&rdt_enable_key)) {
dentry = ERR_PTR(-EBUSY);
goto out;
}
ret = parse_rdtgroupfs_options(data);
if (ret) {
dentry = ERR_PTR(ret);
goto out_cdp;
}
closid_init();
ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
if (ret) {
dentry = ERR_PTR(ret);
goto out_cdp;
}
dentry = kernfs_mount(fs_type, flags, rdt_root,
RDTGROUP_SUPER_MAGIC, NULL);
if (IS_ERR(dentry))
goto out_cdp;
static_branch_enable(&rdt_enable_key);
goto out;
out_cdp:
cdp_disable();
out:
mutex_unlock(&rdtgroup_mutex);
return dentry;
}
static int reset_all_cbms(struct rdt_resource *r)
{
struct msr_param msr_param;
cpumask_var_t cpu_mask;
struct rdt_domain *d;
int i, cpu;
if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
return -ENOMEM;
msr_param.res = r;
msr_param.low = 0;
msr_param.high = r->num_closid;
/*
* Disable resource control for this resource by setting all
* CBMs in all domains to the maximum mask value. Pick one CPU
* from each domain to update the MSRs below.
*/
list_for_each_entry(d, &r->domains, list) {
cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
for (i = 0; i < r->num_closid; i++)
d->cbm[i] = r->max_cbm;
}
cpu = get_cpu();
/* Update CBM on this cpu if it's in cpu_mask. */
if (cpumask_test_cpu(cpu, cpu_mask))
rdt_cbm_update(&msr_param);
/* Update CBM on all other cpus in cpu_mask. */
smp_call_function_many(cpu_mask, rdt_cbm_update, &msr_param, 1);
put_cpu();
free_cpumask_var(cpu_mask);
return 0;
}
/*
* Move tasks from one to the other group. If @from is NULL, then all tasks
* in the systems are moved unconditionally (used for teardown).
*
* If @mask is not NULL the cpus on which moved tasks are running are set
* in that mask so the update smp function call is restricted to affected
* cpus.
*/
static void rdt_move_group_tasks(struct rdtgroup *from, struct rdtgroup *to,
struct cpumask *mask)
{
struct task_struct *p, *t;
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
if (!from || t->closid == from->closid) {
t->closid = to->closid;
#ifdef [31mCONFIG_SMP[0m
/*
* This is safe on x86 w/o barriers as the ordering
* of writing to task_cpu() and t->on_cpu is
* reverse to the reading here. The detection is
* inaccurate as tasks might move or schedule
* before the smp function call takes place. In
* such a case the function call is pointless, but
* there is no other side effect.
*/
if (mask && t->on_cpu)
cpumask_set_cpu(task_cpu(t), mask);
#endif
}
}
read_unlock(&tasklist_lock);
}
/*
* Forcibly remove all of subdirectories under root.
*/
static void rmdir_all_sub(void)
{
struct rdtgroup *rdtgrp, *tmp;
/* Move all tasks to the default resource group */
rdt_move_group_tasks(NULL, &rdtgroup_default, NULL);
list_for_each_entry_safe(rdtgrp, tmp, &rdt_all_groups, rdtgroup_list) {
/* Remove each rdtgroup other than root */
if (rdtgrp == &rdtgroup_default)
continue;
/*
* Give any CPUs back to the default group. We cannot copy
* cpu_online_mask because a CPU might have executed the
* offline callback already, but is still marked online.
*/
cpumask_or(&rdtgroup_default.cpu_mask,
&rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);
kernfs_remove(rdtgrp->kn);
list_del(&rdtgrp->rdtgroup_list);
kfree(rdtgrp);
}
/* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */
get_online_cpus();
rdt_update_closid(cpu_online_mask, &rdtgroup_default.closid);
put_online_cpus();
kernfs_remove(kn_info);
}
static void rdt_kill_sb(struct super_block *sb)
{
struct rdt_resource *r;
mutex_lock(&rdtgroup_mutex);
/*Put everything back to default values. */
for_each_enabled_rdt_resource(r)
reset_all_cbms(r);
cdp_disable();
rmdir_all_sub();
static_branch_disable(&rdt_enable_key);
kernfs_kill_sb(sb);
mutex_unlock(&rdtgroup_mutex);
}
static struct file_system_type rdt_fs_type = {
.name = "resctrl",
.mount = rdt_mount,
.kill_sb = rdt_kill_sb,
};
static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
umode_t mode)
{
struct rdtgroup *parent, *rdtgrp;
struct kernfs_node *kn;
int ret, closid;
/* Only allow mkdir in the root directory */
if (parent_kn != rdtgroup_default.kn)
return -EPERM;
/* Do not accept '\n' to avoid unparsable situation. */
if (strchr(name, '\n'))
return -EINVAL;
parent = rdtgroup_kn_lock_live(parent_kn);
if (!parent) {
ret = -ENODEV;
goto out_unlock;
}
ret = closid_alloc();
if (ret < 0)
goto out_unlock;
closid = ret;
/* allocate the rdtgroup. */
rdtgrp = kzalloc(sizeof(*rdtgrp), GFP_KERNEL);
if (!rdtgrp) {
ret = -ENOSPC;
goto out_closid_free;
}
rdtgrp->closid = closid;
list_add(&rdtgrp->rdtgroup_list, &rdt_all_groups);
/* kernfs creates the directory for rdtgrp */
kn = kernfs_create_dir(parent->kn, name, mode, rdtgrp);
if (IS_ERR(kn)) {
ret = PTR_ERR(kn);
goto out_cancel_ref;
}
rdtgrp->kn = kn;
/*
* kernfs_remove() will drop the reference count on "kn" which
* will free it. But we still need it to stick around for the
* rdtgroup_kn_unlock(kn} call below. Take one extra reference
* here, which will be dropped inside rdtgroup_kn_unlock().
*/
kernfs_get(kn);
ret = rdtgroup_kn_set_ugid(kn);
if (ret)
goto out_destroy;
ret = rdtgroup_add_files(kn, rdtgroup_base_files,
ARRAY_SIZE(rdtgroup_base_files));
if (ret)
goto out_destroy;
kernfs_activate(kn);
ret = 0;
goto out_unlock;
out_destroy:
kernfs_remove(rdtgrp->kn);
out_cancel_ref:
list_del(&rdtgrp->rdtgroup_list);
kfree(rdtgrp);
out_closid_free:
closid_free(closid);
out_unlock:
rdtgroup_kn_unlock(parent_kn);
return ret;
}
static int rdtgroup_rmdir(struct kernfs_node *kn)
{
int ret, cpu, closid = rdtgroup_default.closid;
struct rdtgroup *rdtgrp;
cpumask_var_t tmpmask;
if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
return -ENOMEM;
rdtgrp = rdtgroup_kn_lock_live(kn);
if (!rdtgrp) {
ret = -EPERM;
goto out;
}
/* Give any tasks back to the default group */
rdt_move_group_tasks(rdtgrp, &rdtgroup_default, tmpmask);
/* Give any CPUs back to the default group */
cpumask_or(&rdtgroup_default.cpu_mask,
&rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);
/* Update per cpu closid of the moved CPUs first */
for_each_cpu(cpu, &rdtgrp->cpu_mask)
per_cpu(cpu_closid, cpu) = closid;
/*
* Update the MSR on moved CPUs and CPUs which have moved
* task running on them.
*/
cpumask_or(tmpmask, tmpmask, &rdtgrp->cpu_mask);
rdt_update_closid(tmpmask, NULL);
rdtgrp->flags = RDT_DELETED;
closid_free(rdtgrp->closid);
list_del(&rdtgrp->rdtgroup_list);
/*
* one extra hold on this, will drop when we kfree(rdtgrp)
* in rdtgroup_kn_unlock()
*/
kernfs_get(kn);
kernfs_remove(rdtgrp->kn);
ret = 0;
out:
rdtgroup_kn_unlock(kn);
free_cpumask_var(tmpmask);
return ret;
}
static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
{
if (rdt_resources_all[RDT_RESOURCE_L3DATA].enabled)
seq_puts(seq, ",cdp");
return 0;
}
static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {
.mkdir = rdtgroup_mkdir,
.rmdir = rdtgroup_rmdir,
.show_options = rdtgroup_show_options,
};
static int __init rdtgroup_setup_root(void)
{
int ret;
rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,
KERNFS_ROOT_CREATE_DEACTIVATED,
&rdtgroup_default);
if (IS_ERR(rdt_root))
return PTR_ERR(rdt_root);
mutex_lock(&rdtgroup_mutex);
rdtgroup_default.closid = 0;
list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);
ret = rdtgroup_add_files(rdt_root->kn, rdtgroup_base_files,
ARRAY_SIZE(rdtgroup_base_files));
if (ret) {
kernfs_destroy_root(rdt_root);
goto out;
}
rdtgroup_default.kn = rdt_root->kn;
kernfs_activate(rdtgroup_default.kn);
out:
mutex_unlock(&rdtgroup_mutex);
return ret;
}
/*
* rdtgroup_init - rdtgroup initialization
*
* Setup resctrl file system including set up root, create mount point,
* register rdtgroup filesystem, and initialize files under root directory.
*
* Return: 0 on success or -errno
*/
int __init rdtgroup_init(void)
{
int ret = 0;
ret = rdtgroup_setup_root();
if (ret)
return ret;
ret = sysfs_create_mount_point(fs_kobj, "resctrl");
if (ret)
goto cleanup_root;
ret = register_filesystem(&rdt_fs_type);
if (ret)
goto cleanup_mountpoint;
return 0;
cleanup_mountpoint:
sysfs_remove_mount_point(fs_kobj, "resctrl");
cleanup_root:
kernfs_destroy_root(rdt_root);
return ret;
}