linux/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
Jithu Joseph b61b8bba18 x86/intel_rdt: Prevent pseudo-locking from using stale pointers
When the last CPU in an rdt_domain goes offline, its rdt_domain struct gets
freed. Current pseudo-locking code is unaware of this scenario and tries to
dereference the freed structure in a few places.

Add checks to prevent pseudo-locking code from doing this.

While further work is needed to seamlessly restore resource groups (not
just pseudo-locking) to their configuration when the domain is brought back
online, the immediate issue of invalid pointers is addressed here.

Fixes: f4e80d67a5 ("x86/intel_rdt: Resctrl files reflect pseudo-locked information")
Fixes: 443810fe61 ("x86/intel_rdt: Create debugfs files for pseudo-locking testing")
Fixes: 746e08590b ("x86/intel_rdt: Create character device exposing pseudo-locked region")
Fixes: 33dc3e410a ("x86/intel_rdt: Make CPU information accessible for pseudo-locked regions")
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: gavin.hindman@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/231f742dbb7b00a31cc104416860e27dba6b072d.1539384145.git.reinette.chatre@intel.com
2018-10-19 14:54:28 +02:00

3063 lines
76 KiB
C

/*
* 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/cacheinfo.h>
#include <linux/cpu.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/kernfs.h>
#include <linux/seq_buf.h>
#include <linux/seq_file.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/slab.h>
#include <linux/task_work.h>
#include <uapi/linux/magic.h>
#include <asm/intel_rdt_sched.h>
#include "intel_rdt.h"
DEFINE_STATIC_KEY_FALSE(rdt_enable_key);
DEFINE_STATIC_KEY_FALSE(rdt_mon_enable_key);
DEFINE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
static 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;
/* Kernel fs node for "mon_groups" directory under root */
static struct kernfs_node *kn_mongrp;
/* Kernel fs node for "mon_data" directory under root */
static struct kernfs_node *kn_mondata;
static struct seq_buf last_cmd_status;
static char last_cmd_status_buf[512];
struct dentry *debugfs_resctrl;
void rdt_last_cmd_clear(void)
{
lockdep_assert_held(&rdtgroup_mutex);
seq_buf_clear(&last_cmd_status);
}
void rdt_last_cmd_puts(const char *s)
{
lockdep_assert_held(&rdtgroup_mutex);
seq_buf_puts(&last_cmd_status, s);
}
void rdt_last_cmd_printf(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
lockdep_assert_held(&rdtgroup_mutex);
seq_buf_vprintf(&last_cmd_status, fmt, ap);
va_end(ap);
}
/*
* 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 int closid_free_map_len;
int closids_supported(void)
{
return closid_free_map_len;
}
static void closid_init(void)
{
struct rdt_resource *r;
int rdt_min_closid = 32;
/* Compute rdt_min_closid across all resources */
for_each_alloc_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;
closid_free_map_len = rdt_min_closid;
}
static int closid_alloc(void)
{
u32 closid = ffs(closid_free_map);
if (closid == 0)
return -ENOSPC;
closid--;
closid_free_map &= ~(1 << closid);
return closid;
}
void closid_free(int closid)
{
closid_free_map |= 1 << closid;
}
/**
* closid_allocated - test if provided closid is in use
* @closid: closid to be tested
*
* Return: true if @closid is currently associated with a resource group,
* false if @closid is free
*/
static bool closid_allocated(unsigned int closid)
{
return (closid_free_map & (1 << closid)) == 0;
}
/**
* rdtgroup_mode_by_closid - Return mode of resource group with closid
* @closid: closid if the resource group
*
* Each resource group is associated with a @closid. Here the mode
* of a resource group can be queried by searching for it using its closid.
*
* Return: mode as &enum rdtgrp_mode of resource group with closid @closid
*/
enum rdtgrp_mode rdtgroup_mode_by_closid(int closid)
{
struct rdtgroup *rdtgrp;
list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
if (rdtgrp->closid == closid)
return rdtgrp->mode;
}
return RDT_NUM_MODES;
}
static const char * const rdt_mode_str[] = {
[RDT_MODE_SHAREABLE] = "shareable",
[RDT_MODE_EXCLUSIVE] = "exclusive",
[RDT_MODE_PSEUDO_LOCKSETUP] = "pseudo-locksetup",
[RDT_MODE_PSEUDO_LOCKED] = "pseudo-locked",
};
/**
* rdtgroup_mode_str - Return the string representation of mode
* @mode: the resource group mode as &enum rdtgroup_mode
*
* Return: string representation of valid mode, "unknown" otherwise
*/
static const char *rdtgroup_mode_str(enum rdtgrp_mode mode)
{
if (mode < RDT_MODE_SHAREABLE || mode >= RDT_NUM_MODES)
return "unknown";
return rdt_mode_str[mode];
}
/* 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,
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
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_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 struct kernfs_ops kf_mondata_ops = {
.atomic_write_len = PAGE_SIZE,
.seq_show = rdtgroup_mondata_show,
};
static bool is_cpu_list(struct kernfs_open_file *of)
{
struct rftype *rft = of->kn->priv;
return rft->flags & RFTYPE_FLAGS_CPUS_LIST;
}
static int rdtgroup_cpus_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct rdtgroup *rdtgrp;
struct cpumask *mask;
int ret = 0;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (rdtgrp) {
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
if (!rdtgrp->plr->d) {
rdt_last_cmd_clear();
rdt_last_cmd_puts("Cache domain offline\n");
ret = -ENODEV;
} else {
mask = &rdtgrp->plr->d->cpu_mask;
seq_printf(s, is_cpu_list(of) ?
"%*pbl\n" : "%*pb\n",
cpumask_pr_args(mask));
}
} else {
seq_printf(s, is_cpu_list(of) ? "%*pbl\n" : "%*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 update_closid_rmid() is proteced against __switch_to() because
* preemption is disabled.
*/
static void update_cpu_closid_rmid(void *info)
{
struct rdtgroup *r = info;
if (r) {
this_cpu_write(pqr_state.default_closid, r->closid);
this_cpu_write(pqr_state.default_rmid, r->mon.rmid);
}
/*
* 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/rmids must have been set up before calling this function.
*/
static void
update_closid_rmid(const struct cpumask *cpu_mask, struct rdtgroup *r)
{
int cpu = get_cpu();
if (cpumask_test_cpu(cpu, cpu_mask))
update_cpu_closid_rmid(r);
smp_call_function_many(cpu_mask, update_cpu_closid_rmid, r, 1);
put_cpu();
}
static int cpus_mon_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,
cpumask_var_t tmpmask)
{
struct rdtgroup *prgrp = rdtgrp->mon.parent, *crgrp;
struct list_head *head;
/* Check whether cpus belong to parent ctrl group */
cpumask_andnot(tmpmask, newmask, &prgrp->cpu_mask);
if (cpumask_weight(tmpmask)) {
rdt_last_cmd_puts("can only add CPUs to mongroup that belong to parent\n");
return -EINVAL;
}
/* Check whether cpus are dropped from this group */
cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask);
if (cpumask_weight(tmpmask)) {
/* Give any dropped cpus to parent rdtgroup */
cpumask_or(&prgrp->cpu_mask, &prgrp->cpu_mask, tmpmask);
update_closid_rmid(tmpmask, prgrp);
}
/*
* If we added cpus, remove them from previous group that owned them
* and update per-cpu rmid
*/
cpumask_andnot(tmpmask, newmask, &rdtgrp->cpu_mask);
if (cpumask_weight(tmpmask)) {
head = &prgrp->mon.crdtgrp_list;
list_for_each_entry(crgrp, head, mon.crdtgrp_list) {
if (crgrp == rdtgrp)
continue;
cpumask_andnot(&crgrp->cpu_mask, &crgrp->cpu_mask,
tmpmask);
}
update_closid_rmid(tmpmask, rdtgrp);
}
/* Done pushing/pulling - update this group with new mask */
cpumask_copy(&rdtgrp->cpu_mask, newmask);
return 0;
}
static void cpumask_rdtgrp_clear(struct rdtgroup *r, struct cpumask *m)
{
struct rdtgroup *crgrp;
cpumask_andnot(&r->cpu_mask, &r->cpu_mask, m);
/* update the child mon group masks as well*/
list_for_each_entry(crgrp, &r->mon.crdtgrp_list, mon.crdtgrp_list)
cpumask_and(&crgrp->cpu_mask, &r->cpu_mask, &crgrp->cpu_mask);
}
static int cpus_ctrl_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,
cpumask_var_t tmpmask, cpumask_var_t tmpmask1)
{
struct rdtgroup *r, *crgrp;
struct list_head *head;
/* 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) {
rdt_last_cmd_puts("Can't drop CPUs from default group\n");
return -EINVAL;
}
/* Give any dropped cpus to rdtgroup_default */
cpumask_or(&rdtgroup_default.cpu_mask,
&rdtgroup_default.cpu_mask, tmpmask);
update_closid_rmid(tmpmask, &rdtgroup_default);
}
/*
* If we added cpus, remove them from previous group and
* the prev group's child groups that owned them
* and update per-cpu closid/rmid.
*/
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_and(tmpmask1, &r->cpu_mask, tmpmask);
if (cpumask_weight(tmpmask1))
cpumask_rdtgrp_clear(r, tmpmask1);
}
update_closid_rmid(tmpmask, rdtgrp);
}
/* Done pushing/pulling - update this group with new mask */
cpumask_copy(&rdtgrp->cpu_mask, newmask);
/*
* Clear child mon group masks since there is a new parent mask
* now and update the rmid for the cpus the child lost.
*/
head = &rdtgrp->mon.crdtgrp_list;
list_for_each_entry(crgrp, head, mon.crdtgrp_list) {
cpumask_and(tmpmask, &rdtgrp->cpu_mask, &crgrp->cpu_mask);
update_closid_rmid(tmpmask, rdtgrp);
cpumask_clear(&crgrp->cpu_mask);
}
return 0;
}
static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
cpumask_var_t tmpmask, newmask, tmpmask1;
struct rdtgroup *rdtgrp;
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;
}
if (!zalloc_cpumask_var(&tmpmask1, GFP_KERNEL)) {
free_cpumask_var(tmpmask);
free_cpumask_var(newmask);
return -ENOMEM;
}
rdtgrp = rdtgroup_kn_lock_live(of->kn);
rdt_last_cmd_clear();
if (!rdtgrp) {
ret = -ENOENT;
rdt_last_cmd_puts("directory was removed\n");
goto unlock;
}
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
ret = -EINVAL;
rdt_last_cmd_puts("pseudo-locking in progress\n");
goto unlock;
}
if (is_cpu_list(of))
ret = cpulist_parse(buf, newmask);
else
ret = cpumask_parse(buf, newmask);
if (ret) {
rdt_last_cmd_puts("bad cpu list/mask\n");
goto unlock;
}
/* check that user didn't specify any offline cpus */
cpumask_andnot(tmpmask, newmask, cpu_online_mask);
if (cpumask_weight(tmpmask)) {
ret = -EINVAL;
rdt_last_cmd_puts("can only assign online cpus\n");
goto unlock;
}
if (rdtgrp->type == RDTCTRL_GROUP)
ret = cpus_ctrl_write(rdtgrp, newmask, tmpmask, tmpmask1);
else if (rdtgrp->type == RDTMON_GROUP)
ret = cpus_mon_write(rdtgrp, newmask, tmpmask);
else
ret = -EINVAL;
unlock:
rdtgroup_kn_unlock(of->kn);
free_cpumask_var(tmpmask);
free_cpumask_var(newmask);
free_cpumask_var(tmpmask1);
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;
current->rmid = 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);
rdt_last_cmd_puts("task exited\n");
} else {
/*
* For ctrl_mon groups move both closid and rmid.
* For monitor groups, can move the tasks only from
* their parent CTRL group.
*/
if (rdtgrp->type == RDTCTRL_GROUP) {
tsk->closid = rdtgrp->closid;
tsk->rmid = rdtgrp->mon.rmid;
} else if (rdtgrp->type == RDTMON_GROUP) {
if (rdtgrp->mon.parent->closid == tsk->closid) {
tsk->rmid = rdtgrp->mon.rmid;
} else {
rdt_last_cmd_puts("Can't move task to different control group\n");
ret = -EINVAL;
}
}
}
return ret;
}
/**
* rdtgroup_tasks_assigned - Test if tasks have been assigned to resource group
* @r: Resource group
*
* Return: 1 if tasks have been assigned to @r, 0 otherwise
*/
int rdtgroup_tasks_assigned(struct rdtgroup *r)
{
struct task_struct *p, *t;
int ret = 0;
lockdep_assert_held(&rdtgroup_mutex);
rcu_read_lock();
for_each_process_thread(p, t) {
if ((r->type == RDTCTRL_GROUP && t->closid == r->closid) ||
(r->type == RDTMON_GROUP && t->rmid == r->mon.rmid)) {
ret = 1;
break;
}
}
rcu_read_unlock();
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)) {
rdt_last_cmd_printf("No permission to move task %d\n", task->pid);
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();
rdt_last_cmd_printf("No task %d\n", pid);
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) {
rdtgroup_kn_unlock(of->kn);
return -ENOENT;
}
rdt_last_cmd_clear();
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
ret = -EINVAL;
rdt_last_cmd_puts("pseudo-locking in progress\n");
goto unlock;
}
ret = rdtgroup_move_task(pid, rdtgrp, of);
unlock:
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 ((r->type == RDTCTRL_GROUP && t->closid == r->closid) ||
(r->type == RDTMON_GROUP && t->rmid == r->mon.rmid))
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;
}
static int rdt_last_cmd_status_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
int len;
mutex_lock(&rdtgroup_mutex);
len = seq_buf_used(&last_cmd_status);
if (len)
seq_printf(seq, "%.*s", len, last_cmd_status_buf);
else
seq_puts(seq, "ok\n");
mutex_unlock(&rdtgroup_mutex);
return 0;
}
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_default_ctrl_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->default_ctrl);
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, "%u\n", r->cache.min_cbm_bits);
return 0;
}
static int rdt_shareable_bits_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->cache.shareable_bits);
return 0;
}
/**
* rdt_bit_usage_show - Display current usage of resources
*
* A domain is a shared resource that can now be allocated differently. Here
* we display the current regions of the domain as an annotated bitmask.
* For each domain of this resource its allocation bitmask
* is annotated as below to indicate the current usage of the corresponding bit:
* 0 - currently unused
* X - currently available for sharing and used by software and hardware
* H - currently used by hardware only but available for software use
* S - currently used and shareable by software only
* E - currently used exclusively by one resource group
* P - currently pseudo-locked by one resource group
*/
static int rdt_bit_usage_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
u32 sw_shareable = 0, hw_shareable = 0;
u32 exclusive = 0, pseudo_locked = 0;
struct rdt_domain *dom;
int i, hwb, swb, excl, psl;
enum rdtgrp_mode mode;
bool sep = false;
u32 *ctrl;
mutex_lock(&rdtgroup_mutex);
hw_shareable = r->cache.shareable_bits;
list_for_each_entry(dom, &r->domains, list) {
if (sep)
seq_putc(seq, ';');
ctrl = dom->ctrl_val;
sw_shareable = 0;
exclusive = 0;
seq_printf(seq, "%d=", dom->id);
for (i = 0; i < closids_supported(); i++, ctrl++) {
if (!closid_allocated(i))
continue;
mode = rdtgroup_mode_by_closid(i);
switch (mode) {
case RDT_MODE_SHAREABLE:
sw_shareable |= *ctrl;
break;
case RDT_MODE_EXCLUSIVE:
exclusive |= *ctrl;
break;
case RDT_MODE_PSEUDO_LOCKSETUP:
/*
* RDT_MODE_PSEUDO_LOCKSETUP is possible
* here but not included since the CBM
* associated with this CLOSID in this mode
* is not initialized and no task or cpu can be
* assigned this CLOSID.
*/
break;
case RDT_MODE_PSEUDO_LOCKED:
case RDT_NUM_MODES:
WARN(1,
"invalid mode for closid %d\n", i);
break;
}
}
for (i = r->cache.cbm_len - 1; i >= 0; i--) {
pseudo_locked = dom->plr ? dom->plr->cbm : 0;
hwb = test_bit(i, (unsigned long *)&hw_shareable);
swb = test_bit(i, (unsigned long *)&sw_shareable);
excl = test_bit(i, (unsigned long *)&exclusive);
psl = test_bit(i, (unsigned long *)&pseudo_locked);
if (hwb && swb)
seq_putc(seq, 'X');
else if (hwb && !swb)
seq_putc(seq, 'H');
else if (!hwb && swb)
seq_putc(seq, 'S');
else if (excl)
seq_putc(seq, 'E');
else if (psl)
seq_putc(seq, 'P');
else /* Unused bits remain */
seq_putc(seq, '0');
}
sep = true;
}
seq_putc(seq, '\n');
mutex_unlock(&rdtgroup_mutex);
return 0;
}
static int rdt_min_bw_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
seq_printf(seq, "%u\n", r->membw.min_bw);
return 0;
}
static int rdt_num_rmids_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_rmid);
return 0;
}
static int rdt_mon_features_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
struct mon_evt *mevt;
list_for_each_entry(mevt, &r->evt_list, list)
seq_printf(seq, "%s\n", mevt->name);
return 0;
}
static int rdt_bw_gran_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
seq_printf(seq, "%u\n", r->membw.bw_gran);
return 0;
}
static int rdt_delay_linear_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
seq_printf(seq, "%u\n", r->membw.delay_linear);
return 0;
}
static int max_threshold_occ_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
struct rdt_resource *r = of->kn->parent->priv;
seq_printf(seq, "%u\n", intel_cqm_threshold * r->mon_scale);
return 0;
}
static ssize_t max_threshold_occ_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct rdt_resource *r = of->kn->parent->priv;
unsigned int bytes;
int ret;
ret = kstrtouint(buf, 0, &bytes);
if (ret)
return ret;
if (bytes > (boot_cpu_data.x86_cache_size * 1024))
return -EINVAL;
intel_cqm_threshold = bytes / r->mon_scale;
return nbytes;
}
/*
* rdtgroup_mode_show - Display mode of this resource group
*/
static int rdtgroup_mode_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct rdtgroup *rdtgrp;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
rdtgroup_kn_unlock(of->kn);
return -ENOENT;
}
seq_printf(s, "%s\n", rdtgroup_mode_str(rdtgrp->mode));
rdtgroup_kn_unlock(of->kn);
return 0;
}
/**
* rdt_cdp_peer_get - Retrieve CDP peer if it exists
* @r: RDT resource to which RDT domain @d belongs
* @d: Cache instance for which a CDP peer is requested
* @r_cdp: RDT resource that shares hardware with @r (RDT resource peer)
* Used to return the result.
* @d_cdp: RDT domain that shares hardware with @d (RDT domain peer)
* Used to return the result.
*
* RDT resources are managed independently and by extension the RDT domains
* (RDT resource instances) are managed independently also. The Code and
* Data Prioritization (CDP) RDT resources, while managed independently,
* could refer to the same underlying hardware. For example,
* RDT_RESOURCE_L2CODE and RDT_RESOURCE_L2DATA both refer to the L2 cache.
*
* When provided with an RDT resource @r and an instance of that RDT
* resource @d rdt_cdp_peer_get() will return if there is a peer RDT
* resource and the exact instance that shares the same hardware.
*
* Return: 0 if a CDP peer was found, <0 on error or if no CDP peer exists.
* If a CDP peer was found, @r_cdp will point to the peer RDT resource
* and @d_cdp will point to the peer RDT domain.
*/
static int rdt_cdp_peer_get(struct rdt_resource *r, struct rdt_domain *d,
struct rdt_resource **r_cdp,
struct rdt_domain **d_cdp)
{
struct rdt_resource *_r_cdp = NULL;
struct rdt_domain *_d_cdp = NULL;
int ret = 0;
switch (r->rid) {
case RDT_RESOURCE_L3DATA:
_r_cdp = &rdt_resources_all[RDT_RESOURCE_L3CODE];
break;
case RDT_RESOURCE_L3CODE:
_r_cdp = &rdt_resources_all[RDT_RESOURCE_L3DATA];
break;
case RDT_RESOURCE_L2DATA:
_r_cdp = &rdt_resources_all[RDT_RESOURCE_L2CODE];
break;
case RDT_RESOURCE_L2CODE:
_r_cdp = &rdt_resources_all[RDT_RESOURCE_L2DATA];
break;
default:
ret = -ENOENT;
goto out;
}
/*
* When a new CPU comes online and CDP is enabled then the new
* RDT domains (if any) associated with both CDP RDT resources
* are added in the same CPU online routine while the
* rdtgroup_mutex is held. It should thus not happen for one
* RDT domain to exist and be associated with its RDT CDP
* resource but there is no RDT domain associated with the
* peer RDT CDP resource. Hence the WARN.
*/
_d_cdp = rdt_find_domain(_r_cdp, d->id, NULL);
if (WARN_ON(!_d_cdp)) {
_r_cdp = NULL;
ret = -EINVAL;
}
out:
*r_cdp = _r_cdp;
*d_cdp = _d_cdp;
return ret;
}
/**
* __rdtgroup_cbm_overlaps - Does CBM for intended closid overlap with other
* @r: Resource to which domain instance @d belongs.
* @d: The domain instance for which @closid is being tested.
* @cbm: Capacity bitmask being tested.
* @closid: Intended closid for @cbm.
* @exclusive: Only check if overlaps with exclusive resource groups
*
* Checks if provided @cbm intended to be used for @closid on domain
* @d overlaps with any other closids or other hardware usage associated
* with this domain. If @exclusive is true then only overlaps with
* resource groups in exclusive mode will be considered. If @exclusive
* is false then overlaps with any resource group or hardware entities
* will be considered.
*
* @cbm is unsigned long, even if only 32 bits are used, to make the
* bitmap functions work correctly.
*
* Return: false if CBM does not overlap, true if it does.
*/
static bool __rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d,
unsigned long cbm, int closid, bool exclusive)
{
enum rdtgrp_mode mode;
unsigned long ctrl_b;
u32 *ctrl;
int i;
/* Check for any overlap with regions used by hardware directly */
if (!exclusive) {
ctrl_b = r->cache.shareable_bits;
if (bitmap_intersects(&cbm, &ctrl_b, r->cache.cbm_len))
return true;
}
/* Check for overlap with other resource groups */
ctrl = d->ctrl_val;
for (i = 0; i < closids_supported(); i++, ctrl++) {
ctrl_b = *ctrl;
mode = rdtgroup_mode_by_closid(i);
if (closid_allocated(i) && i != closid &&
mode != RDT_MODE_PSEUDO_LOCKSETUP) {
if (bitmap_intersects(&cbm, &ctrl_b, r->cache.cbm_len)) {
if (exclusive) {
if (mode == RDT_MODE_EXCLUSIVE)
return true;
continue;
}
return true;
}
}
}
return false;
}
/**
* rdtgroup_cbm_overlaps - Does CBM overlap with other use of hardware
* @r: Resource to which domain instance @d belongs.
* @d: The domain instance for which @closid is being tested.
* @cbm: Capacity bitmask being tested.
* @closid: Intended closid for @cbm.
* @exclusive: Only check if overlaps with exclusive resource groups
*
* Resources that can be allocated using a CBM can use the CBM to control
* the overlap of these allocations. rdtgroup_cmb_overlaps() is the test
* for overlap. Overlap test is not limited to the specific resource for
* which the CBM is intended though - when dealing with CDP resources that
* share the underlying hardware the overlap check should be performed on
* the CDP resource sharing the hardware also.
*
* Refer to description of __rdtgroup_cbm_overlaps() for the details of the
* overlap test.
*
* Return: true if CBM overlap detected, false if there is no overlap
*/
bool rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d,
unsigned long cbm, int closid, bool exclusive)
{
struct rdt_resource *r_cdp;
struct rdt_domain *d_cdp;
if (__rdtgroup_cbm_overlaps(r, d, cbm, closid, exclusive))
return true;
if (rdt_cdp_peer_get(r, d, &r_cdp, &d_cdp) < 0)
return false;
return __rdtgroup_cbm_overlaps(r_cdp, d_cdp, cbm, closid, exclusive);
}
/**
* rdtgroup_mode_test_exclusive - Test if this resource group can be exclusive
*
* An exclusive resource group implies that there should be no sharing of
* its allocated resources. At the time this group is considered to be
* exclusive this test can determine if its current schemata supports this
* setting by testing for overlap with all other resource groups.
*
* Return: true if resource group can be exclusive, false if there is overlap
* with allocations of other resource groups and thus this resource group
* cannot be exclusive.
*/
static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)
{
int closid = rdtgrp->closid;
struct rdt_resource *r;
bool has_cache = false;
struct rdt_domain *d;
for_each_alloc_enabled_rdt_resource(r) {
if (r->rid == RDT_RESOURCE_MBA)
continue;
has_cache = true;
list_for_each_entry(d, &r->domains, list) {
if (rdtgroup_cbm_overlaps(r, d, d->ctrl_val[closid],
rdtgrp->closid, false)) {
rdt_last_cmd_puts("schemata overlaps\n");
return false;
}
}
}
if (!has_cache) {
rdt_last_cmd_puts("cannot be exclusive without CAT/CDP\n");
return false;
}
return true;
}
/**
* rdtgroup_mode_write - Modify the resource group's mode
*
*/
static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct rdtgroup *rdtgrp;
enum rdtgrp_mode mode;
int ret = 0;
/* Valid input requires a trailing newline */
if (nbytes == 0 || buf[nbytes - 1] != '\n')
return -EINVAL;
buf[nbytes - 1] = '\0';
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
rdtgroup_kn_unlock(of->kn);
return -ENOENT;
}
rdt_last_cmd_clear();
mode = rdtgrp->mode;
if ((!strcmp(buf, "shareable") && mode == RDT_MODE_SHAREABLE) ||
(!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE) ||
(!strcmp(buf, "pseudo-locksetup") &&
mode == RDT_MODE_PSEUDO_LOCKSETUP) ||
(!strcmp(buf, "pseudo-locked") && mode == RDT_MODE_PSEUDO_LOCKED))
goto out;
if (mode == RDT_MODE_PSEUDO_LOCKED) {
rdt_last_cmd_printf("cannot change pseudo-locked group\n");
ret = -EINVAL;
goto out;
}
if (!strcmp(buf, "shareable")) {
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
ret = rdtgroup_locksetup_exit(rdtgrp);
if (ret)
goto out;
}
rdtgrp->mode = RDT_MODE_SHAREABLE;
} else if (!strcmp(buf, "exclusive")) {
if (!rdtgroup_mode_test_exclusive(rdtgrp)) {
ret = -EINVAL;
goto out;
}
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
ret = rdtgroup_locksetup_exit(rdtgrp);
if (ret)
goto out;
}
rdtgrp->mode = RDT_MODE_EXCLUSIVE;
} else if (!strcmp(buf, "pseudo-locksetup")) {
ret = rdtgroup_locksetup_enter(rdtgrp);
if (ret)
goto out;
rdtgrp->mode = RDT_MODE_PSEUDO_LOCKSETUP;
} else {
rdt_last_cmd_printf("unknown/unsupported mode\n");
ret = -EINVAL;
}
out:
rdtgroup_kn_unlock(of->kn);
return ret ?: nbytes;
}
/**
* rdtgroup_cbm_to_size - Translate CBM to size in bytes
* @r: RDT resource to which @d belongs.
* @d: RDT domain instance.
* @cbm: bitmask for which the size should be computed.
*
* The bitmask provided associated with the RDT domain instance @d will be
* translated into how many bytes it represents. The size in bytes is
* computed by first dividing the total cache size by the CBM length to
* determine how many bytes each bit in the bitmask represents. The result
* is multiplied with the number of bits set in the bitmask.
*
* @cbm is unsigned long, even if only 32 bits are used to make the
* bitmap functions work correctly.
*/
unsigned int rdtgroup_cbm_to_size(struct rdt_resource *r,
struct rdt_domain *d, unsigned long cbm)
{
struct cpu_cacheinfo *ci;
unsigned int size = 0;
int num_b, i;
num_b = bitmap_weight(&cbm, r->cache.cbm_len);
ci = get_cpu_cacheinfo(cpumask_any(&d->cpu_mask));
for (i = 0; i < ci->num_leaves; i++) {
if (ci->info_list[i].level == r->cache_level) {
size = ci->info_list[i].size / r->cache.cbm_len * num_b;
break;
}
}
return size;
}
/**
* rdtgroup_size_show - Display size in bytes of allocated regions
*
* The "size" file mirrors the layout of the "schemata" file, printing the
* size in bytes of each region instead of the capacity bitmask.
*
*/
static int rdtgroup_size_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
struct rdt_domain *d;
unsigned int size;
int ret = 0;
bool sep;
u32 ctrl;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
rdtgroup_kn_unlock(of->kn);
return -ENOENT;
}
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
if (!rdtgrp->plr->d) {
rdt_last_cmd_clear();
rdt_last_cmd_puts("Cache domain offline\n");
ret = -ENODEV;
} else {
seq_printf(s, "%*s:", max_name_width,
rdtgrp->plr->r->name);
size = rdtgroup_cbm_to_size(rdtgrp->plr->r,
rdtgrp->plr->d,
rdtgrp->plr->cbm);
seq_printf(s, "%d=%u\n", rdtgrp->plr->d->id, size);
}
goto out;
}
for_each_alloc_enabled_rdt_resource(r) {
sep = false;
seq_printf(s, "%*s:", max_name_width, r->name);
list_for_each_entry(d, &r->domains, list) {
if (sep)
seq_putc(s, ';');
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
size = 0;
} else {
ctrl = (!is_mba_sc(r) ?
d->ctrl_val[rdtgrp->closid] :
d->mbps_val[rdtgrp->closid]);
if (r->rid == RDT_RESOURCE_MBA)
size = ctrl;
else
size = rdtgroup_cbm_to_size(r, d, ctrl);
}
seq_printf(s, "%d=%u", d->id, size);
sep = true;
}
seq_putc(s, '\n');
}
out:
rdtgroup_kn_unlock(of->kn);
return ret;
}
/* rdtgroup information files for one cache resource. */
static struct rftype res_common_files[] = {
{
.name = "last_cmd_status",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_last_cmd_status_show,
.fflags = RF_TOP_INFO,
},
{
.name = "num_closids",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_num_closids_show,
.fflags = RF_CTRL_INFO,
},
{
.name = "mon_features",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_mon_features_show,
.fflags = RF_MON_INFO,
},
{
.name = "num_rmids",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_num_rmids_show,
.fflags = RF_MON_INFO,
},
{
.name = "cbm_mask",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_default_ctrl_show,
.fflags = RF_CTRL_INFO | RFTYPE_RES_CACHE,
},
{
.name = "min_cbm_bits",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_min_cbm_bits_show,
.fflags = RF_CTRL_INFO | RFTYPE_RES_CACHE,
},
{
.name = "shareable_bits",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_shareable_bits_show,
.fflags = RF_CTRL_INFO | RFTYPE_RES_CACHE,
},
{
.name = "bit_usage",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_bit_usage_show,
.fflags = RF_CTRL_INFO | RFTYPE_RES_CACHE,
},
{
.name = "min_bandwidth",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_min_bw_show,
.fflags = RF_CTRL_INFO | RFTYPE_RES_MB,
},
{
.name = "bandwidth_gran",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_bw_gran_show,
.fflags = RF_CTRL_INFO | RFTYPE_RES_MB,
},
{
.name = "delay_linear",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdt_delay_linear_show,
.fflags = RF_CTRL_INFO | RFTYPE_RES_MB,
},
{
.name = "max_threshold_occupancy",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = max_threshold_occ_write,
.seq_show = max_threshold_occ_show,
.fflags = RF_MON_INFO | RFTYPE_RES_CACHE,
},
{
.name = "cpus",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_cpus_write,
.seq_show = rdtgroup_cpus_show,
.fflags = RFTYPE_BASE,
},
{
.name = "cpus_list",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_cpus_write,
.seq_show = rdtgroup_cpus_show,
.flags = RFTYPE_FLAGS_CPUS_LIST,
.fflags = RFTYPE_BASE,
},
{
.name = "tasks",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_tasks_write,
.seq_show = rdtgroup_tasks_show,
.fflags = RFTYPE_BASE,
},
{
.name = "schemata",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_schemata_write,
.seq_show = rdtgroup_schemata_show,
.fflags = RF_CTRL_BASE,
},
{
.name = "mode",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_mode_write,
.seq_show = rdtgroup_mode_show,
.fflags = RF_CTRL_BASE,
},
{
.name = "size",
.mode = 0444,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdtgroup_size_show,
.fflags = RF_CTRL_BASE,
},
};
static int rdtgroup_add_files(struct kernfs_node *kn, unsigned long fflags)
{
struct rftype *rfts, *rft;
int ret, len;
rfts = res_common_files;
len = ARRAY_SIZE(res_common_files);
lockdep_assert_held(&rdtgroup_mutex);
for (rft = rfts; rft < rfts + len; rft++) {
if ((fflags & rft->fflags) == rft->fflags) {
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) {
if ((fflags & rft->fflags) == rft->fflags)
kernfs_remove_by_name(kn, rft->name);
}
return ret;
}
/**
* rdtgroup_kn_mode_restrict - Restrict user access to named resctrl file
* @r: The resource group with which the file is associated.
* @name: Name of the file
*
* The permissions of named resctrl file, directory, or link are modified
* to not allow read, write, or execute by any user.
*
* WARNING: This function is intended to communicate to the user that the
* resctrl file has been locked down - that it is not relevant to the
* particular state the system finds itself in. It should not be relied
* on to protect from user access because after the file's permissions
* are restricted the user can still change the permissions using chmod
* from the command line.
*
* Return: 0 on success, <0 on failure.
*/
int rdtgroup_kn_mode_restrict(struct rdtgroup *r, const char *name)
{
struct iattr iattr = {.ia_valid = ATTR_MODE,};
struct kernfs_node *kn;
int ret = 0;
kn = kernfs_find_and_get_ns(r->kn, name, NULL);
if (!kn)
return -ENOENT;
switch (kernfs_type(kn)) {
case KERNFS_DIR:
iattr.ia_mode = S_IFDIR;
break;
case KERNFS_FILE:
iattr.ia_mode = S_IFREG;
break;
case KERNFS_LINK:
iattr.ia_mode = S_IFLNK;
break;
}
ret = kernfs_setattr(kn, &iattr);
kernfs_put(kn);
return ret;
}
/**
* rdtgroup_kn_mode_restore - Restore user access to named resctrl file
* @r: The resource group with which the file is associated.
* @name: Name of the file
* @mask: Mask of permissions that should be restored
*
* Restore the permissions of the named file. If @name is a directory the
* permissions of its parent will be used.
*
* Return: 0 on success, <0 on failure.
*/
int rdtgroup_kn_mode_restore(struct rdtgroup *r, const char *name,
umode_t mask)
{
struct iattr iattr = {.ia_valid = ATTR_MODE,};
struct kernfs_node *kn, *parent;
struct rftype *rfts, *rft;
int ret, len;
rfts = res_common_files;
len = ARRAY_SIZE(res_common_files);
for (rft = rfts; rft < rfts + len; rft++) {
if (!strcmp(rft->name, name))
iattr.ia_mode = rft->mode & mask;
}
kn = kernfs_find_and_get_ns(r->kn, name, NULL);
if (!kn)
return -ENOENT;
switch (kernfs_type(kn)) {
case KERNFS_DIR:
parent = kernfs_get_parent(kn);
if (parent) {
iattr.ia_mode |= parent->mode;
kernfs_put(parent);
}
iattr.ia_mode |= S_IFDIR;
break;
case KERNFS_FILE:
iattr.ia_mode |= S_IFREG;
break;
case KERNFS_LINK:
iattr.ia_mode |= S_IFLNK;
break;
}
ret = kernfs_setattr(kn, &iattr);
kernfs_put(kn);
return ret;
}
static int rdtgroup_mkdir_info_resdir(struct rdt_resource *r, char *name,
unsigned long fflags)
{
struct kernfs_node *kn_subdir;
int ret;
kn_subdir = kernfs_create_dir(kn_info, name,
kn_info->mode, r);
if (IS_ERR(kn_subdir))
return PTR_ERR(kn_subdir);
kernfs_get(kn_subdir);
ret = rdtgroup_kn_set_ugid(kn_subdir);
if (ret)
return ret;
ret = rdtgroup_add_files(kn_subdir, fflags);
if (!ret)
kernfs_activate(kn_subdir);
return ret;
}
static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
{
struct rdt_resource *r;
unsigned long fflags;
char name[32];
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);
ret = rdtgroup_add_files(kn_info, RF_TOP_INFO);
if (ret)
goto out_destroy;
for_each_alloc_enabled_rdt_resource(r) {
fflags = r->fflags | RF_CTRL_INFO;
ret = rdtgroup_mkdir_info_resdir(r, r->name, fflags);
if (ret)
goto out_destroy;
}
for_each_mon_enabled_rdt_resource(r) {
fflags = r->fflags | RF_MON_INFO;
sprintf(name, "%s_MON", r->name);
ret = rdtgroup_mkdir_info_resdir(r, name, fflags);
if (ret)
goto out_destroy;
}
/*
* 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 int
mongroup_create_dir(struct kernfs_node *parent_kn, struct rdtgroup *prgrp,
char *name, struct kernfs_node **dest_kn)
{
struct kernfs_node *kn;
int ret;
/* create the directory */
kn = kernfs_create_dir(parent_kn, name, parent_kn->mode, prgrp);
if (IS_ERR(kn))
return PTR_ERR(kn);
if (dest_kn)
*dest_kn = kn;
/*
* This extra ref will be put in kernfs_remove() and guarantees
* that @rdtgrp->kn is always accessible.
*/
kernfs_get(kn);
ret = rdtgroup_kn_set_ugid(kn);
if (ret)
goto out_destroy;
kernfs_activate(kn);
return 0;
out_destroy:
kernfs_remove(kn);
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 void l2_qos_cfg_update(void *arg)
{
bool *enable = arg;
wrmsrl(IA32_L2_QOS_CFG, *enable ? L2_QOS_CDP_ENABLE : 0ULL);
}
static inline bool is_mba_linear(void)
{
return rdt_resources_all[RDT_RESOURCE_MBA].membw.delay_linear;
}
static int set_cache_qos_cfg(int level, bool enable)
{
void (*update)(void *arg);
struct rdt_resource *r_l;
cpumask_var_t cpu_mask;
struct rdt_domain *d;
int cpu;
if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
return -ENOMEM;
if (level == RDT_RESOURCE_L3)
update = l3_qos_cfg_update;
else if (level == RDT_RESOURCE_L2)
update = l2_qos_cfg_update;
else
return -EINVAL;
r_l = &rdt_resources_all[level];
list_for_each_entry(d, &r_l->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))
update(&enable);
/* Update QOS_CFG MSR on all other cpus in cpu_mask. */
smp_call_function_many(cpu_mask, update, &enable, 1);
put_cpu();
free_cpumask_var(cpu_mask);
return 0;
}
/*
* Enable or disable the MBA software controller
* which helps user specify bandwidth in MBps.
* MBA software controller is supported only if
* MBM is supported and MBA is in linear scale.
*/
static int set_mba_sc(bool mba_sc)
{
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA];
struct rdt_domain *d;
if (!is_mbm_enabled() || !is_mba_linear() ||
mba_sc == is_mba_sc(r))
return -EINVAL;
r->membw.mba_sc = mba_sc;
list_for_each_entry(d, &r->domains, list)
setup_default_ctrlval(r, d->ctrl_val, d->mbps_val);
return 0;
}
static int cdp_enable(int level, int data_type, int code_type)
{
struct rdt_resource *r_ldata = &rdt_resources_all[data_type];
struct rdt_resource *r_lcode = &rdt_resources_all[code_type];
struct rdt_resource *r_l = &rdt_resources_all[level];
int ret;
if (!r_l->alloc_capable || !r_ldata->alloc_capable ||
!r_lcode->alloc_capable)
return -EINVAL;
ret = set_cache_qos_cfg(level, true);
if (!ret) {
r_l->alloc_enabled = false;
r_ldata->alloc_enabled = true;
r_lcode->alloc_enabled = true;
}
return ret;
}
static int cdpl3_enable(void)
{
return cdp_enable(RDT_RESOURCE_L3, RDT_RESOURCE_L3DATA,
RDT_RESOURCE_L3CODE);
}
static int cdpl2_enable(void)
{
return cdp_enable(RDT_RESOURCE_L2, RDT_RESOURCE_L2DATA,
RDT_RESOURCE_L2CODE);
}
static void cdp_disable(int level, int data_type, int code_type)
{
struct rdt_resource *r = &rdt_resources_all[level];
r->alloc_enabled = r->alloc_capable;
if (rdt_resources_all[data_type].alloc_enabled) {
rdt_resources_all[data_type].alloc_enabled = false;
rdt_resources_all[code_type].alloc_enabled = false;
set_cache_qos_cfg(level, false);
}
}
static void cdpl3_disable(void)
{
cdp_disable(RDT_RESOURCE_L3, RDT_RESOURCE_L3DATA, RDT_RESOURCE_L3CODE);
}
static void cdpl2_disable(void)
{
cdp_disable(RDT_RESOURCE_L2, RDT_RESOURCE_L2DATA, RDT_RESOURCE_L2CODE);
}
static void cdp_disable_all(void)
{
if (rdt_resources_all[RDT_RESOURCE_L3DATA].alloc_enabled)
cdpl3_disable();
if (rdt_resources_all[RDT_RESOURCE_L2DATA].alloc_enabled)
cdpl2_disable();
}
static int parse_rdtgroupfs_options(char *data)
{
char *token, *o = data;
int ret = 0;
while ((token = strsep(&o, ",")) != NULL) {
if (!*token) {
ret = -EINVAL;
goto out;
}
if (!strcmp(token, "cdp")) {
ret = cdpl3_enable();
if (ret)
goto out;
} else if (!strcmp(token, "cdpl2")) {
ret = cdpl2_enable();
if (ret)
goto out;
} else if (!strcmp(token, "mba_MBps")) {
ret = set_mba_sc(true);
if (ret)
goto out;
} else {
ret = -EINVAL;
goto out;
}
}
return 0;
out:
pr_err("Invalid mount option \"%s\"\n", token);
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)) {
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)
rdtgroup_pseudo_lock_remove(rdtgrp);
kernfs_unbreak_active_protection(kn);
kernfs_put(rdtgrp->kn);
kfree(rdtgrp);
} else {
kernfs_unbreak_active_protection(kn);
}
}
static int mkdir_mondata_all(struct kernfs_node *parent_kn,
struct rdtgroup *prgrp,
struct kernfs_node **mon_data_kn);
static struct dentry *rdt_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data)
{
struct rdt_domain *dom;
struct rdt_resource *r;
struct dentry *dentry;
int ret;
cpus_read_lock();
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;
}
if (rdt_mon_capable) {
ret = mongroup_create_dir(rdtgroup_default.kn,
NULL, "mon_groups",
&kn_mongrp);
if (ret) {
dentry = ERR_PTR(ret);
goto out_info;
}
kernfs_get(kn_mongrp);
ret = mkdir_mondata_all(rdtgroup_default.kn,
&rdtgroup_default, &kn_mondata);
if (ret) {
dentry = ERR_PTR(ret);
goto out_mongrp;
}
kernfs_get(kn_mondata);
rdtgroup_default.mon.mon_data_kn = kn_mondata;
}
ret = rdt_pseudo_lock_init();
if (ret) {
dentry = ERR_PTR(ret);
goto out_mondata;
}
dentry = kernfs_mount(fs_type, flags, rdt_root,
RDTGROUP_SUPER_MAGIC, NULL);
if (IS_ERR(dentry))
goto out_psl;
if (rdt_alloc_capable)
static_branch_enable_cpuslocked(&rdt_alloc_enable_key);
if (rdt_mon_capable)
static_branch_enable_cpuslocked(&rdt_mon_enable_key);
if (rdt_alloc_capable || rdt_mon_capable)
static_branch_enable_cpuslocked(&rdt_enable_key);
if (is_mbm_enabled()) {
r = &rdt_resources_all[RDT_RESOURCE_L3];
list_for_each_entry(dom, &r->domains, list)
mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL);
}
goto out;
out_psl:
rdt_pseudo_lock_release();
out_mondata:
if (rdt_mon_capable)
kernfs_remove(kn_mondata);
out_mongrp:
if (rdt_mon_capable)
kernfs_remove(kn_mongrp);
out_info:
kernfs_remove(kn_info);
out_cdp:
cdp_disable_all();
out:
rdt_last_cmd_clear();
mutex_unlock(&rdtgroup_mutex);
cpus_read_unlock();
return dentry;
}
static int reset_all_ctrls(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->ctrl_val[i] = r->default_ctrl;
}
cpu = get_cpu();
/* Update CBM on this cpu if it's in cpu_mask. */
if (cpumask_test_cpu(cpu, cpu_mask))
rdt_ctrl_update(&msr_param);
/* Update CBM on all other cpus in cpu_mask. */
smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
put_cpu();
free_cpumask_var(cpu_mask);
return 0;
}
static bool is_closid_match(struct task_struct *t, struct rdtgroup *r)
{
return (rdt_alloc_capable &&
(r->type == RDTCTRL_GROUP) && (t->closid == r->closid));
}
static bool is_rmid_match(struct task_struct *t, struct rdtgroup *r)
{
return (rdt_mon_capable &&
(r->type == RDTMON_GROUP) && (t->rmid == r->mon.rmid));
}
/*
* 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 || is_closid_match(t, from) ||
is_rmid_match(t, from)) {
t->closid = to->closid;
t->rmid = to->mon.rmid;
#ifdef CONFIG_SMP
/*
* 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);
}
static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp)
{
struct rdtgroup *sentry, *stmp;
struct list_head *head;
head = &rdtgrp->mon.crdtgrp_list;
list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) {
free_rmid(sentry->mon.rmid);
list_del(&sentry->mon.crdtgrp_list);
kfree(sentry);
}
}
/*
* 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) {
/* Free any child rmids */
free_all_child_rdtgrp(rdtgrp);
/* Remove each rdtgroup other than root */
if (rdtgrp == &rdtgroup_default)
continue;
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)
rdtgroup_pseudo_lock_remove(rdtgrp);
/*
* 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);
free_rmid(rdtgrp->mon.rmid);
kernfs_remove(rdtgrp->kn);
list_del(&rdtgrp->rdtgroup_list);
kfree(rdtgrp);
}
/* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */
update_closid_rmid(cpu_online_mask, &rdtgroup_default);
kernfs_remove(kn_info);
kernfs_remove(kn_mongrp);
kernfs_remove(kn_mondata);
}
static void rdt_kill_sb(struct super_block *sb)
{
struct rdt_resource *r;
cpus_read_lock();
mutex_lock(&rdtgroup_mutex);
set_mba_sc(false);
/*Put everything back to default values. */
for_each_alloc_enabled_rdt_resource(r)
reset_all_ctrls(r);
cdp_disable_all();
rmdir_all_sub();
rdt_pseudo_lock_release();
rdtgroup_default.mode = RDT_MODE_SHAREABLE;
static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
static_branch_disable_cpuslocked(&rdt_mon_enable_key);
static_branch_disable_cpuslocked(&rdt_enable_key);
kernfs_kill_sb(sb);
mutex_unlock(&rdtgroup_mutex);
cpus_read_unlock();
}
static struct file_system_type rdt_fs_type = {
.name = "resctrl",
.mount = rdt_mount,
.kill_sb = rdt_kill_sb,
};
static int mon_addfile(struct kernfs_node *parent_kn, const char *name,
void *priv)
{
struct kernfs_node *kn;
int ret = 0;
kn = __kernfs_create_file(parent_kn, name, 0444,
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 0,
&kf_mondata_ops, priv, NULL, NULL);
if (IS_ERR(kn))
return PTR_ERR(kn);
ret = rdtgroup_kn_set_ugid(kn);
if (ret) {
kernfs_remove(kn);
return ret;
}
return ret;
}
/*
* Remove all subdirectories of mon_data of ctrl_mon groups
* and monitor groups with given domain id.
*/
void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int dom_id)
{
struct rdtgroup *prgrp, *crgrp;
char name[32];
if (!r->mon_enabled)
return;
list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
sprintf(name, "mon_%s_%02d", r->name, dom_id);
kernfs_remove_by_name(prgrp->mon.mon_data_kn, name);
list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
kernfs_remove_by_name(crgrp->mon.mon_data_kn, name);
}
}
static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
struct rdt_domain *d,
struct rdt_resource *r, struct rdtgroup *prgrp)
{
union mon_data_bits priv;
struct kernfs_node *kn;
struct mon_evt *mevt;
struct rmid_read rr;
char name[32];
int ret;
sprintf(name, "mon_%s_%02d", r->name, d->id);
/* create the directory */
kn = kernfs_create_dir(parent_kn, name, parent_kn->mode, prgrp);
if (IS_ERR(kn))
return PTR_ERR(kn);
/*
* This extra ref will be put in kernfs_remove() and guarantees
* that kn is always accessible.
*/
kernfs_get(kn);
ret = rdtgroup_kn_set_ugid(kn);
if (ret)
goto out_destroy;
if (WARN_ON(list_empty(&r->evt_list))) {
ret = -EPERM;
goto out_destroy;
}
priv.u.rid = r->rid;
priv.u.domid = d->id;
list_for_each_entry(mevt, &r->evt_list, list) {
priv.u.evtid = mevt->evtid;
ret = mon_addfile(kn, mevt->name, priv.priv);
if (ret)
goto out_destroy;
if (is_mbm_event(mevt->evtid))
mon_event_read(&rr, d, prgrp, mevt->evtid, true);
}
kernfs_activate(kn);
return 0;
out_destroy:
kernfs_remove(kn);
return ret;
}
/*
* Add all subdirectories of mon_data for "ctrl_mon" groups
* and "monitor" groups with given domain id.
*/
void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
struct rdt_domain *d)
{
struct kernfs_node *parent_kn;
struct rdtgroup *prgrp, *crgrp;
struct list_head *head;
if (!r->mon_enabled)
return;
list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
parent_kn = prgrp->mon.mon_data_kn;
mkdir_mondata_subdir(parent_kn, d, r, prgrp);
head = &prgrp->mon.crdtgrp_list;
list_for_each_entry(crgrp, head, mon.crdtgrp_list) {
parent_kn = crgrp->mon.mon_data_kn;
mkdir_mondata_subdir(parent_kn, d, r, crgrp);
}
}
}
static int mkdir_mondata_subdir_alldom(struct kernfs_node *parent_kn,
struct rdt_resource *r,
struct rdtgroup *prgrp)
{
struct rdt_domain *dom;
int ret;
list_for_each_entry(dom, &r->domains, list) {
ret = mkdir_mondata_subdir(parent_kn, dom, r, prgrp);
if (ret)
return ret;
}
return 0;
}
/*
* This creates a directory mon_data which contains the monitored data.
*
* mon_data has one directory for each domain whic are named
* in the format mon_<domain_name>_<domain_id>. For ex: A mon_data
* with L3 domain looks as below:
* ./mon_data:
* mon_L3_00
* mon_L3_01
* mon_L3_02
* ...
*
* Each domain directory has one file per event:
* ./mon_L3_00/:
* llc_occupancy
*
*/
static int mkdir_mondata_all(struct kernfs_node *parent_kn,
struct rdtgroup *prgrp,
struct kernfs_node **dest_kn)
{
struct rdt_resource *r;
struct kernfs_node *kn;
int ret;
/*
* Create the mon_data directory first.
*/
ret = mongroup_create_dir(parent_kn, NULL, "mon_data", &kn);
if (ret)
return ret;
if (dest_kn)
*dest_kn = kn;
/*
* Create the subdirectories for each domain. Note that all events
* in a domain like L3 are grouped into a resource whose domain is L3
*/
for_each_mon_enabled_rdt_resource(r) {
ret = mkdir_mondata_subdir_alldom(kn, r, prgrp);
if (ret)
goto out_destroy;
}
return 0;
out_destroy:
kernfs_remove(kn);
return ret;
}
/**
* cbm_ensure_valid - Enforce validity on provided CBM
* @_val: Candidate CBM
* @r: RDT resource to which the CBM belongs
*
* The provided CBM represents all cache portions available for use. This
* may be represented by a bitmap that does not consist of contiguous ones
* and thus be an invalid CBM.
* Here the provided CBM is forced to be a valid CBM by only considering
* the first set of contiguous bits as valid and clearing all bits.
* The intention here is to provide a valid default CBM with which a new
* resource group is initialized. The user can follow this with a
* modification to the CBM if the default does not satisfy the
* requirements.
*/
static void cbm_ensure_valid(u32 *_val, struct rdt_resource *r)
{
/*
* Convert the u32 _val to an unsigned long required by all the bit
* operations within this function. No more than 32 bits of this
* converted value can be accessed because all bit operations are
* additionally provided with cbm_len that is initialized during
* hardware enumeration using five bits from the EAX register and
* thus never can exceed 32 bits.
*/
unsigned long *val = (unsigned long *)_val;
unsigned int cbm_len = r->cache.cbm_len;
unsigned long first_bit, zero_bit;
if (*val == 0)
return;
first_bit = find_first_bit(val, cbm_len);
zero_bit = find_next_zero_bit(val, cbm_len, first_bit);
/* Clear any remaining bits to ensure contiguous region */
bitmap_clear(val, zero_bit, cbm_len - zero_bit);
}
/**
* rdtgroup_init_alloc - Initialize the new RDT group's allocations
*
* A new RDT group is being created on an allocation capable (CAT)
* supporting system. Set this group up to start off with all usable
* allocations. That is, all shareable and unused bits.
*
* All-zero CBM is invalid. If there are no more shareable bits available
* on any domain then the entire allocation will fail.
*/
static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
{
struct rdt_resource *r_cdp = NULL;
struct rdt_domain *d_cdp = NULL;
u32 used_b = 0, unused_b = 0;
u32 closid = rdtgrp->closid;
struct rdt_resource *r;
unsigned long tmp_cbm;
enum rdtgrp_mode mode;
struct rdt_domain *d;
u32 peer_ctl, *ctrl;
int i, ret;
for_each_alloc_enabled_rdt_resource(r) {
/*
* Only initialize default allocations for CBM cache
* resources
*/
if (r->rid == RDT_RESOURCE_MBA)
continue;
list_for_each_entry(d, &r->domains, list) {
rdt_cdp_peer_get(r, d, &r_cdp, &d_cdp);
d->have_new_ctrl = false;
d->new_ctrl = r->cache.shareable_bits;
used_b = r->cache.shareable_bits;
ctrl = d->ctrl_val;
for (i = 0; i < closids_supported(); i++, ctrl++) {
if (closid_allocated(i) && i != closid) {
mode = rdtgroup_mode_by_closid(i);
if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
break;
/*
* If CDP is active include peer
* domain's usage to ensure there
* is no overlap with an exclusive
* group.
*/
if (d_cdp)
peer_ctl = d_cdp->ctrl_val[i];
else
peer_ctl = 0;
used_b |= *ctrl | peer_ctl;
if (mode == RDT_MODE_SHAREABLE)
d->new_ctrl |= *ctrl | peer_ctl;
}
}
if (d->plr && d->plr->cbm > 0)
used_b |= d->plr->cbm;
unused_b = used_b ^ (BIT_MASK(r->cache.cbm_len) - 1);
unused_b &= BIT_MASK(r->cache.cbm_len) - 1;
d->new_ctrl |= unused_b;
/*
* Force the initial CBM to be valid, user can
* modify the CBM based on system availability.
*/
cbm_ensure_valid(&d->new_ctrl, r);
/*
* Assign the u32 CBM to an unsigned long to ensure
* that bitmap_weight() does not access out-of-bound
* memory.
*/
tmp_cbm = d->new_ctrl;
if (bitmap_weight(&tmp_cbm, r->cache.cbm_len) <
r->cache.min_cbm_bits) {
rdt_last_cmd_printf("no space on %s:%d\n",
r->name, d->id);
return -ENOSPC;
}
d->have_new_ctrl = true;
}
}
for_each_alloc_enabled_rdt_resource(r) {
/*
* Only initialize default allocations for CBM cache
* resources
*/
if (r->rid == RDT_RESOURCE_MBA)
continue;
ret = update_domains(r, rdtgrp->closid);
if (ret < 0) {
rdt_last_cmd_puts("failed to initialize allocations\n");
return ret;
}
rdtgrp->mode = RDT_MODE_SHAREABLE;
}
return 0;
}
static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
struct kernfs_node *prgrp_kn,
const char *name, umode_t mode,
enum rdt_group_type rtype, struct rdtgroup **r)
{
struct rdtgroup *prdtgrp, *rdtgrp;
struct kernfs_node *kn;
uint files = 0;
int ret;
prdtgrp = rdtgroup_kn_lock_live(prgrp_kn);
rdt_last_cmd_clear();
if (!prdtgrp) {
ret = -ENODEV;
rdt_last_cmd_puts("directory was removed\n");
goto out_unlock;
}
if (rtype == RDTMON_GROUP &&
(prdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
prdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)) {
ret = -EINVAL;
rdt_last_cmd_puts("pseudo-locking in progress\n");
goto out_unlock;
}
/* allocate the rdtgroup. */
rdtgrp = kzalloc(sizeof(*rdtgrp), GFP_KERNEL);
if (!rdtgrp) {
ret = -ENOSPC;
rdt_last_cmd_puts("kernel out of memory\n");
goto out_unlock;
}
*r = rdtgrp;
rdtgrp->mon.parent = prdtgrp;
rdtgrp->type = rtype;
INIT_LIST_HEAD(&rdtgrp->mon.crdtgrp_list);
/* kernfs creates the directory for rdtgrp */
kn = kernfs_create_dir(parent_kn, name, mode, rdtgrp);
if (IS_ERR(kn)) {
ret = PTR_ERR(kn);
rdt_last_cmd_puts("kernfs create error\n");
goto out_free_rgrp;
}
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) {
rdt_last_cmd_puts("kernfs perm error\n");
goto out_destroy;
}
files = RFTYPE_BASE | BIT(RF_CTRLSHIFT + rtype);
ret = rdtgroup_add_files(kn, files);
if (ret) {
rdt_last_cmd_puts("kernfs fill error\n");
goto out_destroy;
}
if (rdt_mon_capable) {
ret = alloc_rmid();
if (ret < 0) {
rdt_last_cmd_puts("out of RMIDs\n");
goto out_destroy;
}
rdtgrp->mon.rmid = ret;
ret = mkdir_mondata_all(kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
if (ret) {
rdt_last_cmd_puts("kernfs subdir error\n");
goto out_idfree;
}
}
kernfs_activate(kn);
/*
* The caller unlocks the prgrp_kn upon success.
*/
return 0;
out_idfree:
free_rmid(rdtgrp->mon.rmid);
out_destroy:
kernfs_remove(rdtgrp->kn);
out_free_rgrp:
kfree(rdtgrp);
out_unlock:
rdtgroup_kn_unlock(prgrp_kn);
return ret;
}
static void mkdir_rdt_prepare_clean(struct rdtgroup *rgrp)
{
kernfs_remove(rgrp->kn);
free_rmid(rgrp->mon.rmid);
kfree(rgrp);
}
/*
* Create a monitor group under "mon_groups" directory of a control
* and monitor group(ctrl_mon). This is a resource group
* to monitor a subset of tasks and cpus in its parent ctrl_mon group.
*/
static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
struct kernfs_node *prgrp_kn,
const char *name,
umode_t mode)
{
struct rdtgroup *rdtgrp, *prgrp;
int ret;
ret = mkdir_rdt_prepare(parent_kn, prgrp_kn, name, mode, RDTMON_GROUP,
&rdtgrp);
if (ret)
return ret;
prgrp = rdtgrp->mon.parent;
rdtgrp->closid = prgrp->closid;
/*
* Add the rdtgrp to the list of rdtgrps the parent
* ctrl_mon group has to track.
*/
list_add_tail(&rdtgrp->mon.crdtgrp_list, &prgrp->mon.crdtgrp_list);
rdtgroup_kn_unlock(prgrp_kn);
return ret;
}
/*
* These are rdtgroups created under the root directory. Can be used
* to allocate and monitor resources.
*/
static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
struct kernfs_node *prgrp_kn,
const char *name, umode_t mode)
{
struct rdtgroup *rdtgrp;
struct kernfs_node *kn;
u32 closid;
int ret;
ret = mkdir_rdt_prepare(parent_kn, prgrp_kn, name, mode, RDTCTRL_GROUP,
&rdtgrp);
if (ret)
return ret;
kn = rdtgrp->kn;
ret = closid_alloc();
if (ret < 0) {
rdt_last_cmd_puts("out of CLOSIDs\n");
goto out_common_fail;
}
closid = ret;
ret = 0;
rdtgrp->closid = closid;
ret = rdtgroup_init_alloc(rdtgrp);
if (ret < 0)
goto out_id_free;
list_add(&rdtgrp->rdtgroup_list, &rdt_all_groups);
if (rdt_mon_capable) {
/*
* Create an empty mon_groups directory to hold the subset
* of tasks and cpus to monitor.
*/
ret = mongroup_create_dir(kn, NULL, "mon_groups", NULL);
if (ret) {
rdt_last_cmd_puts("kernfs subdir error\n");
goto out_del_list;
}
}
goto out_unlock;
out_del_list:
list_del(&rdtgrp->rdtgroup_list);
out_id_free:
closid_free(closid);
out_common_fail:
mkdir_rdt_prepare_clean(rdtgrp);
out_unlock:
rdtgroup_kn_unlock(prgrp_kn);
return ret;
}
/*
* We allow creating mon groups only with in a directory called "mon_groups"
* which is present in every ctrl_mon group. Check if this is a valid
* "mon_groups" directory.
*
* 1. The directory should be named "mon_groups".
* 2. The mon group itself should "not" be named "mon_groups".
* This makes sure "mon_groups" directory always has a ctrl_mon group
* as parent.
*/
static bool is_mon_groups(struct kernfs_node *kn, const char *name)
{
return (!strcmp(kn->name, "mon_groups") &&
strcmp(name, "mon_groups"));
}
static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
umode_t mode)
{
/* Do not accept '\n' to avoid unparsable situation. */
if (strchr(name, '\n'))
return -EINVAL;
/*
* If the parent directory is the root directory and RDT
* allocation is supported, add a control and monitoring
* subdirectory
*/
if (rdt_alloc_capable && parent_kn == rdtgroup_default.kn)
return rdtgroup_mkdir_ctrl_mon(parent_kn, parent_kn, name, mode);
/*
* If RDT monitoring is supported and the parent directory is a valid
* "mon_groups" directory, add a monitoring subdirectory.
*/
if (rdt_mon_capable && is_mon_groups(parent_kn, name))
return rdtgroup_mkdir_mon(parent_kn, parent_kn->parent, name, mode);
return -EPERM;
}
static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
cpumask_var_t tmpmask)
{
struct rdtgroup *prdtgrp = rdtgrp->mon.parent;
int cpu;
/* Give any tasks back to the parent group */
rdt_move_group_tasks(rdtgrp, prdtgrp, tmpmask);
/* Update per cpu rmid of the moved CPUs first */
for_each_cpu(cpu, &rdtgrp->cpu_mask)
per_cpu(pqr_state.default_rmid, cpu) = prdtgrp->mon.rmid;
/*
* Update the MSR on moved CPUs and CPUs which have moved
* task running on them.
*/
cpumask_or(tmpmask, tmpmask, &rdtgrp->cpu_mask);
update_closid_rmid(tmpmask, NULL);
rdtgrp->flags = RDT_DELETED;
free_rmid(rdtgrp->mon.rmid);
/*
* Remove the rdtgrp from the parent ctrl_mon group's list
*/
WARN_ON(list_empty(&prdtgrp->mon.crdtgrp_list));
list_del(&rdtgrp->mon.crdtgrp_list);
/*
* one extra hold on this, will drop when we kfree(rdtgrp)
* in rdtgroup_kn_unlock()
*/
kernfs_get(kn);
kernfs_remove(rdtgrp->kn);
return 0;
}
static int rdtgroup_ctrl_remove(struct kernfs_node *kn,
struct rdtgroup *rdtgrp)
{
rdtgrp->flags = RDT_DELETED;
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);
return 0;
}
static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
cpumask_var_t tmpmask)
{
int cpu;
/* 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 and rmid of the moved CPUs first */
for_each_cpu(cpu, &rdtgrp->cpu_mask) {
per_cpu(pqr_state.default_closid, cpu) = rdtgroup_default.closid;
per_cpu(pqr_state.default_rmid, cpu) = rdtgroup_default.mon.rmid;
}
/*
* Update the MSR on moved CPUs and CPUs which have moved
* task running on them.
*/
cpumask_or(tmpmask, tmpmask, &rdtgrp->cpu_mask);
update_closid_rmid(tmpmask, NULL);
closid_free(rdtgrp->closid);
free_rmid(rdtgrp->mon.rmid);
/*
* Free all the child monitor group rmids.
*/
free_all_child_rdtgrp(rdtgrp);
rdtgroup_ctrl_remove(kn, rdtgrp);
return 0;
}
static int rdtgroup_rmdir(struct kernfs_node *kn)
{
struct kernfs_node *parent_kn = kn->parent;
struct rdtgroup *rdtgrp;
cpumask_var_t tmpmask;
int ret = 0;
if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
return -ENOMEM;
rdtgrp = rdtgroup_kn_lock_live(kn);
if (!rdtgrp) {
ret = -EPERM;
goto out;
}
/*
* If the rdtgroup is a ctrl_mon group and parent directory
* is the root directory, remove the ctrl_mon group.
*
* If the rdtgroup is a mon group and parent directory
* is a valid "mon_groups" directory, remove the mon group.
*/
if (rdtgrp->type == RDTCTRL_GROUP && parent_kn == rdtgroup_default.kn) {
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
ret = rdtgroup_ctrl_remove(kn, rdtgrp);
} else {
ret = rdtgroup_rmdir_ctrl(kn, rdtgrp, tmpmask);
}
} else if (rdtgrp->type == RDTMON_GROUP &&
is_mon_groups(parent_kn, kn->name)) {
ret = rdtgroup_rmdir_mon(kn, rdtgrp, tmpmask);
} else {
ret = -EPERM;
}
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].alloc_enabled)
seq_puts(seq, ",cdp");
if (rdt_resources_all[RDT_RESOURCE_L2DATA].alloc_enabled)
seq_puts(seq, ",cdpl2");
if (is_mba_sc(&rdt_resources_all[RDT_RESOURCE_MBA]))
seq_puts(seq, ",mba_MBps");
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 |
KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK,
&rdtgroup_default);
if (IS_ERR(rdt_root))
return PTR_ERR(rdt_root);
mutex_lock(&rdtgroup_mutex);
rdtgroup_default.closid = 0;
rdtgroup_default.mon.rmid = 0;
rdtgroup_default.type = RDTCTRL_GROUP;
INIT_LIST_HEAD(&rdtgroup_default.mon.crdtgrp_list);
list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);
ret = rdtgroup_add_files(rdt_root->kn, RF_CTRL_BASE);
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;
seq_buf_init(&last_cmd_status, last_cmd_status_buf,
sizeof(last_cmd_status_buf));
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;
/*
* Adding the resctrl debugfs directory here may not be ideal since
* it would let the resctrl debugfs directory appear on the debugfs
* filesystem before the resctrl filesystem is mounted.
* It may also be ok since that would enable debugging of RDT before
* resctrl is mounted.
* The reason why the debugfs directory is created here and not in
* rdt_mount() is because rdt_mount() takes rdtgroup_mutex and
* during the debugfs directory creation also &sb->s_type->i_mutex_key
* (the lockdep class of inode->i_rwsem). Other filesystem
* interactions (eg. SyS_getdents) have the lock ordering:
* &sb->s_type->i_mutex_key --> &mm->mmap_sem
* During mmap(), called with &mm->mmap_sem, the rdtgroup_mutex
* is taken, thus creating dependency:
* &mm->mmap_sem --> rdtgroup_mutex for the latter that can cause
* issues considering the other two lock dependencies.
* By creating the debugfs directory here we avoid a dependency
* that may cause deadlock (even though file operations cannot
* occur until the filesystem is mounted, but I do not know how to
* tell lockdep that).
*/
debugfs_resctrl = debugfs_create_dir("resctrl", NULL);
return 0;
cleanup_mountpoint:
sysfs_remove_mount_point(fs_kobj, "resctrl");
cleanup_root:
kernfs_destroy_root(rdt_root);
return ret;
}
void __exit rdtgroup_exit(void)
{
debugfs_remove_recursive(debugfs_resctrl);
unregister_filesystem(&rdt_fs_type);
sysfs_remove_mount_point(fs_kobj, "resctrl");
kernfs_destroy_root(rdt_root);
}