linux/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.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

484 lines
12 KiB
C

/*
* Resource Director Technology(RDT)
* - Cache Allocation code.
*
* Copyright (C) 2016 Intel Corporation
*
* Authors:
* Fenghua Yu <fenghua.yu@intel.com>
* Tony Luck <tony.luck@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 June 2016, volume 3, section 17.17.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernfs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include "intel_rdt.h"
/*
* Check whether MBA bandwidth percentage value is correct. The value is
* checked against the minimum and max bandwidth values specified by the
* hardware. The allocated bandwidth percentage is rounded to the next
* control step available on the hardware.
*/
static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
{
unsigned long bw;
int ret;
/*
* Only linear delay values is supported for current Intel SKUs.
*/
if (!r->membw.delay_linear) {
rdt_last_cmd_puts("No support for non-linear MB domains\n");
return false;
}
ret = kstrtoul(buf, 10, &bw);
if (ret) {
rdt_last_cmd_printf("Non-decimal digit in MB value %s\n", buf);
return false;
}
if ((bw < r->membw.min_bw || bw > r->default_ctrl) &&
!is_mba_sc(r)) {
rdt_last_cmd_printf("MB value %ld out of range [%d,%d]\n", bw,
r->membw.min_bw, r->default_ctrl);
return false;
}
*data = roundup(bw, (unsigned long)r->membw.bw_gran);
return true;
}
int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
struct rdt_domain *d)
{
unsigned long bw_val;
if (d->have_new_ctrl) {
rdt_last_cmd_printf("duplicate domain %d\n", d->id);
return -EINVAL;
}
if (!bw_validate(data->buf, &bw_val, r))
return -EINVAL;
d->new_ctrl = bw_val;
d->have_new_ctrl = true;
return 0;
}
/*
* Check whether a cache bit mask is valid. The SDM says:
* Please note that all (and only) contiguous '1' combinations
* are allowed (e.g. FFFFH, 0FF0H, 003CH, etc.).
* Additionally Haswell requires at least two bits set.
*/
static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
{
unsigned long first_bit, zero_bit, val;
unsigned int cbm_len = r->cache.cbm_len;
int ret;
ret = kstrtoul(buf, 16, &val);
if (ret) {
rdt_last_cmd_printf("non-hex character in mask %s\n", buf);
return false;
}
if (val == 0 || val > r->default_ctrl) {
rdt_last_cmd_puts("mask out of range\n");
return false;
}
first_bit = find_first_bit(&val, cbm_len);
zero_bit = find_next_zero_bit(&val, cbm_len, first_bit);
if (find_next_bit(&val, cbm_len, zero_bit) < cbm_len) {
rdt_last_cmd_printf("mask %lx has non-consecutive 1-bits\n", val);
return false;
}
if ((zero_bit - first_bit) < r->cache.min_cbm_bits) {
rdt_last_cmd_printf("Need at least %d bits in mask\n",
r->cache.min_cbm_bits);
return false;
}
*data = val;
return true;
}
/*
* Read one cache bit mask (hex). Check that it is valid for the current
* resource type.
*/
int parse_cbm(struct rdt_parse_data *data, struct rdt_resource *r,
struct rdt_domain *d)
{
struct rdtgroup *rdtgrp = data->rdtgrp;
u32 cbm_val;
if (d->have_new_ctrl) {
rdt_last_cmd_printf("duplicate domain %d\n", d->id);
return -EINVAL;
}
/*
* Cannot set up more than one pseudo-locked region in a cache
* hierarchy.
*/
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
rdtgroup_pseudo_locked_in_hierarchy(d)) {
rdt_last_cmd_printf("pseudo-locked region in hierarchy\n");
return -EINVAL;
}
if (!cbm_validate(data->buf, &cbm_val, r))
return -EINVAL;
if ((rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
rdtgrp->mode == RDT_MODE_SHAREABLE) &&
rdtgroup_cbm_overlaps_pseudo_locked(d, cbm_val)) {
rdt_last_cmd_printf("CBM overlaps with pseudo-locked region\n");
return -EINVAL;
}
/*
* The CBM may not overlap with the CBM of another closid if
* either is exclusive.
*/
if (rdtgroup_cbm_overlaps(r, d, cbm_val, rdtgrp->closid, true)) {
rdt_last_cmd_printf("overlaps with exclusive group\n");
return -EINVAL;
}
if (rdtgroup_cbm_overlaps(r, d, cbm_val, rdtgrp->closid, false)) {
if (rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
rdt_last_cmd_printf("overlaps with other group\n");
return -EINVAL;
}
}
d->new_ctrl = cbm_val;
d->have_new_ctrl = true;
return 0;
}
/*
* For each domain in this resource we expect to find a series of:
* id=mask
* separated by ";". The "id" is in decimal, and must match one of
* the "id"s for this resource.
*/
static int parse_line(char *line, struct rdt_resource *r,
struct rdtgroup *rdtgrp)
{
struct rdt_parse_data data;
char *dom = NULL, *id;
struct rdt_domain *d;
unsigned long dom_id;
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
r->rid == RDT_RESOURCE_MBA) {
rdt_last_cmd_puts("Cannot pseudo-lock MBA resource\n");
return -EINVAL;
}
next:
if (!line || line[0] == '\0')
return 0;
dom = strsep(&line, ";");
id = strsep(&dom, "=");
if (!dom || kstrtoul(id, 10, &dom_id)) {
rdt_last_cmd_puts("Missing '=' or non-numeric domain\n");
return -EINVAL;
}
dom = strim(dom);
list_for_each_entry(d, &r->domains, list) {
if (d->id == dom_id) {
data.buf = dom;
data.rdtgrp = rdtgrp;
if (r->parse_ctrlval(&data, r, d))
return -EINVAL;
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
/*
* In pseudo-locking setup mode and just
* parsed a valid CBM that should be
* pseudo-locked. Only one locked region per
* resource group and domain so just do
* the required initialization for single
* region and return.
*/
rdtgrp->plr->r = r;
rdtgrp->plr->d = d;
rdtgrp->plr->cbm = d->new_ctrl;
d->plr = rdtgrp->plr;
return 0;
}
goto next;
}
}
return -EINVAL;
}
int update_domains(struct rdt_resource *r, int closid)
{
struct msr_param msr_param;
cpumask_var_t cpu_mask;
struct rdt_domain *d;
bool mba_sc;
u32 *dc;
int cpu;
if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
return -ENOMEM;
msr_param.low = closid;
msr_param.high = msr_param.low + 1;
msr_param.res = r;
mba_sc = is_mba_sc(r);
list_for_each_entry(d, &r->domains, list) {
dc = !mba_sc ? d->ctrl_val : d->mbps_val;
if (d->have_new_ctrl && d->new_ctrl != dc[closid]) {
cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
dc[closid] = d->new_ctrl;
}
}
/*
* Avoid writing the control msr with control values when
* MBA software controller is enabled
*/
if (cpumask_empty(cpu_mask) || mba_sc)
goto done;
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 other cpus. */
smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
put_cpu();
done:
free_cpumask_var(cpu_mask);
return 0;
}
static int rdtgroup_parse_resource(char *resname, char *tok,
struct rdtgroup *rdtgrp)
{
struct rdt_resource *r;
for_each_alloc_enabled_rdt_resource(r) {
if (!strcmp(resname, r->name) && rdtgrp->closid < r->num_closid)
return parse_line(tok, r, rdtgrp);
}
rdt_last_cmd_printf("unknown/unsupported resource name '%s'\n", resname);
return -EINVAL;
}
ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct rdtgroup *rdtgrp;
struct rdt_domain *dom;
struct rdt_resource *r;
char *tok, *resname;
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();
/*
* No changes to pseudo-locked region allowed. It has to be removed
* and re-created instead.
*/
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
ret = -EINVAL;
rdt_last_cmd_puts("resource group is pseudo-locked\n");
goto out;
}
for_each_alloc_enabled_rdt_resource(r) {
list_for_each_entry(dom, &r->domains, list)
dom->have_new_ctrl = false;
}
while ((tok = strsep(&buf, "\n")) != NULL) {
resname = strim(strsep(&tok, ":"));
if (!tok) {
rdt_last_cmd_puts("Missing ':'\n");
ret = -EINVAL;
goto out;
}
if (tok[0] == '\0') {
rdt_last_cmd_printf("Missing '%s' value\n", resname);
ret = -EINVAL;
goto out;
}
ret = rdtgroup_parse_resource(resname, tok, rdtgrp);
if (ret)
goto out;
}
for_each_alloc_enabled_rdt_resource(r) {
ret = update_domains(r, rdtgrp->closid);
if (ret)
goto out;
}
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
/*
* If pseudo-locking fails we keep the resource group in
* mode RDT_MODE_PSEUDO_LOCKSETUP with its class of service
* active and updated for just the domain the pseudo-locked
* region was requested for.
*/
ret = rdtgroup_pseudo_lock_create(rdtgrp);
}
out:
rdtgroup_kn_unlock(of->kn);
return ret ?: nbytes;
}
static void show_doms(struct seq_file *s, struct rdt_resource *r, int closid)
{
struct rdt_domain *dom;
bool sep = false;
u32 ctrl_val;
seq_printf(s, "%*s:", max_name_width, r->name);
list_for_each_entry(dom, &r->domains, list) {
if (sep)
seq_puts(s, ";");
ctrl_val = (!is_mba_sc(r) ? dom->ctrl_val[closid] :
dom->mbps_val[closid]);
seq_printf(s, r->format_str, dom->id, max_data_width,
ctrl_val);
sep = true;
}
seq_puts(s, "\n");
}
int rdtgroup_schemata_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
int ret = 0;
u32 closid;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (rdtgrp) {
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
for_each_alloc_enabled_rdt_resource(r)
seq_printf(s, "%s:uninitialized\n", r->name);
} else 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:%d=%x\n",
rdtgrp->plr->r->name,
rdtgrp->plr->d->id,
rdtgrp->plr->cbm);
}
} else {
closid = rdtgrp->closid;
for_each_alloc_enabled_rdt_resource(r) {
if (closid < r->num_closid)
show_doms(s, r, closid);
}
}
} else {
ret = -ENOENT;
}
rdtgroup_kn_unlock(of->kn);
return ret;
}
void mon_event_read(struct rmid_read *rr, struct rdt_domain *d,
struct rdtgroup *rdtgrp, int evtid, int first)
{
/*
* setup the parameters to send to the IPI to read the data.
*/
rr->rgrp = rdtgrp;
rr->evtid = evtid;
rr->d = d;
rr->val = 0;
rr->first = first;
smp_call_function_any(&d->cpu_mask, mon_event_count, rr, 1);
}
int rdtgroup_mondata_show(struct seq_file *m, void *arg)
{
struct kernfs_open_file *of = m->private;
u32 resid, evtid, domid;
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
union mon_data_bits md;
struct rdt_domain *d;
struct rmid_read rr;
int ret = 0;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
md.priv = of->kn->priv;
resid = md.u.rid;
domid = md.u.domid;
evtid = md.u.evtid;
r = &rdt_resources_all[resid];
d = rdt_find_domain(r, domid, NULL);
if (!d) {
ret = -ENOENT;
goto out;
}
mon_event_read(&rr, d, rdtgrp, evtid, false);
if (rr.val & RMID_VAL_ERROR)
seq_puts(m, "Error\n");
else if (rr.val & RMID_VAL_UNAVAIL)
seq_puts(m, "Unavailable\n");
else
seq_printf(m, "%llu\n", rr.val * r->mon_scale);
out:
rdtgroup_kn_unlock(of->kn);
return ret;
}