cpuset: Handle CPU_WHICH_TIDPID wherever cpuset_which() is called.

[FreeBSD/FreeBSD.git] / sys / kern / kern_cpuset.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2008,  Jeffrey Roberson <jeff@freebsd.org>
 * All rights reserved.
 * 
 * Copyright (c) 2008 Nokia Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "opt_ddb.h"
#include "opt_ktrace.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/ctype.h>
#include <sys/sysproto.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/refcount.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/capsicum.h>
#include <sys/cpuset.h>
#include <sys/domainset.h>
#include <sys/sx.h>
#include <sys/queue.h>
#include <sys/libkern.h>
#include <sys/limits.h>
#include <sys/bus.h>
#include <sys/interrupt.h>
#include <sys/vmmeter.h>
#include <sys/ktrace.h>

#include <vm/uma.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_extern.h>
#include <vm/vm_param.h>
#include <vm/vm_phys.h>
#include <vm/vm_pagequeue.h>

#ifdef DDB
#include <ddb/ddb.h>
#endif /* DDB */

/*
 * cpusets provide a mechanism for creating and manipulating sets of
 * processors for the purpose of constraining the scheduling of threads to
 * specific processors.
 *
 * Each process belongs to an identified set, by default this is set 1.  Each
 * thread may further restrict the cpus it may run on to a subset of this
 * named set.  This creates an anonymous set which other threads and processes
 * may not join by number.
 *
 * The named set is referred to herein as the 'base' set to avoid ambiguity.
 * This set is usually a child of a 'root' set while the anonymous set may
 * simply be referred to as a mask.  In the syscall api these are referred to
 * as the ROOT, CPUSET, and MASK levels where CPUSET is called 'base' here.
 *
 * Threads inherit their set from their creator whether it be anonymous or
 * not.  This means that anonymous sets are immutable because they may be
 * shared.  To modify an anonymous set a new set is created with the desired
 * mask and the same parent as the existing anonymous set.  This gives the
 * illusion of each thread having a private mask.
 *
 * Via the syscall apis a user may ask to retrieve or modify the root, base,
 * or mask that is discovered via a pid, tid, or setid.  Modifying a set
 * modifies all numbered and anonymous child sets to comply with the new mask.
 * Modifying a pid or tid's mask applies only to that tid but must still
 * exist within the assigned parent set.
 *
 * A thread may not be assigned to a group separate from other threads in
 * the process.  This is to remove ambiguity when the setid is queried with
 * a pid argument.  There is no other technical limitation.
 *
 * This somewhat complex arrangement is intended to make it easy for
 * applications to query available processors and bind their threads to
 * specific processors while also allowing administrators to dynamically
 * reprovision by changing sets which apply to groups of processes.
 *
 * A simple application should not concern itself with sets at all and
 * rather apply masks to its own threads via CPU_WHICH_TID and a -1 id
 * meaning 'curthread'.  It may query available cpus for that tid with a
 * getaffinity call using (CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1, ...).
 */

LIST_HEAD(domainlist, domainset);
struct domainset __read_mostly domainset_firsttouch;
struct domainset __read_mostly domainset_fixed[MAXMEMDOM];
struct domainset __read_mostly domainset_interleave;
struct domainset __read_mostly domainset_prefer[MAXMEMDOM];
struct domainset __read_mostly domainset_roundrobin;

static uma_zone_t cpuset_zone;
static uma_zone_t domainset_zone;
static struct mtx cpuset_lock;
static struct setlist cpuset_ids;
static struct domainlist cpuset_domains;
static struct unrhdr *cpuset_unr;
static struct cpuset *cpuset_zero, *cpuset_default, *cpuset_kernel;
static struct domainset *domainset0, *domainset2;
u_int cpusetsizemin = 1;

/* Return the size of cpuset_t at the kernel level */
SYSCTL_INT(_kern_sched, OID_AUTO, cpusetsize, CTLFLAG_RD | CTLFLAG_CAPRD,
    SYSCTL_NULL_INT_PTR, sizeof(cpuset_t), "sizeof(cpuset_t)");

/* Return the minimum size of cpuset_t allowed by the kernel */
SYSCTL_UINT(_kern_sched, OID_AUTO, cpusetsizemin,
    CTLFLAG_RD | CTLFLAG_CAPRD, &cpusetsizemin, 0,
    "The minimum size of cpuset_t allowed by the kernel");

cpuset_t *cpuset_root;
cpuset_t cpuset_domain[MAXMEMDOM];

static int cpuset_which2(cpuwhich_t *, id_t, struct proc **, struct thread **,
    struct cpuset **);
static int domainset_valid(const struct domainset *, const struct domainset *);

/*
 * Find the first non-anonymous set starting from 'set'.
 */
static struct cpuset *
cpuset_getbase(struct cpuset *set)
{

        if (set->cs_id == CPUSET_INVALID)
                set = set->cs_parent;
        return (set);
}

/*
 * Walks up the tree from 'set' to find the root.
 */
static struct cpuset *
cpuset_getroot(struct cpuset *set)
{

        while ((set->cs_flags & CPU_SET_ROOT) == 0 && set->cs_parent != NULL)
                set = set->cs_parent;
        return (set);
}

/*
 * Acquire a reference to a cpuset, all pointers must be tracked with refs.
 */
struct cpuset *
cpuset_ref(struct cpuset *set)
{

        refcount_acquire(&set->cs_ref);
        return (set);
}

/*
 * Walks up the tree from 'set' to find the root.  Returns the root
 * referenced.
 */
static struct cpuset *
cpuset_refroot(struct cpuset *set)
{

        return (cpuset_ref(cpuset_getroot(set)));
}

/*
 * Find the first non-anonymous set starting from 'set'.  Returns this set
 * referenced.  May return the passed in set with an extra ref if it is
 * not anonymous. 
 */
static struct cpuset *
cpuset_refbase(struct cpuset *set)
{

        return (cpuset_ref(cpuset_getbase(set)));
}

/*
 * Release a reference in a context where it is safe to allocate.
 */
void
cpuset_rel(struct cpuset *set)
{
        cpusetid_t id;

        if (refcount_release_if_not_last(&set->cs_ref))
                return;
        mtx_lock_spin(&cpuset_lock);
        if (!refcount_release(&set->cs_ref)) {
                mtx_unlock_spin(&cpuset_lock);
                return;
        }
        LIST_REMOVE(set, cs_siblings);
        id = set->cs_id;
        if (id != CPUSET_INVALID)
                LIST_REMOVE(set, cs_link);
        mtx_unlock_spin(&cpuset_lock);
        cpuset_rel(set->cs_parent);
        uma_zfree(cpuset_zone, set);
        if (id != CPUSET_INVALID)
                free_unr(cpuset_unr, id);
}

/*
 * Deferred release must be used when in a context that is not safe to
 * allocate/free.  This places any unreferenced sets on the list 'head'.
 */
static void
cpuset_rel_defer(struct setlist *head, struct cpuset *set)
{

        if (refcount_release_if_not_last(&set->cs_ref))
                return;
        mtx_lock_spin(&cpuset_lock);
        if (!refcount_release(&set->cs_ref)) {
                mtx_unlock_spin(&cpuset_lock);
                return;
        }
        LIST_REMOVE(set, cs_siblings);
        if (set->cs_id != CPUSET_INVALID)
                LIST_REMOVE(set, cs_link);
        LIST_INSERT_HEAD(head, set, cs_link);
        mtx_unlock_spin(&cpuset_lock);
}

/*
 * Complete a deferred release.  Removes the set from the list provided to
 * cpuset_rel_defer.
 */
static void
cpuset_rel_complete(struct cpuset *set)
{
        cpusetid_t id;

        id = set->cs_id;
        LIST_REMOVE(set, cs_link);
        cpuset_rel(set->cs_parent);
        uma_zfree(cpuset_zone, set);
        if (id != CPUSET_INVALID)
                free_unr(cpuset_unr, id);
}

/*
 * Find a set based on an id.  Returns it with a ref.
 */
static struct cpuset *
cpuset_lookup(cpusetid_t setid, struct thread *td)
{
        struct cpuset *set;

        if (setid == CPUSET_INVALID)
                return (NULL);
        mtx_lock_spin(&cpuset_lock);
        LIST_FOREACH(set, &cpuset_ids, cs_link)
                if (set->cs_id == setid)
                        break;
        if (set)
                cpuset_ref(set);
        mtx_unlock_spin(&cpuset_lock);

        KASSERT(td != NULL, ("[%s:%d] td is NULL", __func__, __LINE__));
        if (set != NULL && jailed(td->td_ucred)) {
                struct cpuset *jset, *tset;

                jset = td->td_ucred->cr_prison->pr_cpuset;
                for (tset = set; tset != NULL; tset = tset->cs_parent)
                        if (tset == jset)
                                break;
                if (tset == NULL) {
                        cpuset_rel(set);
                        set = NULL;
                }
        }

        return (set);
}

/*
 * Initialize a set in the space provided in 'set' with the provided parameters.
 * The set is returned with a single ref.  May return EDEADLK if the set
 * will have no valid cpu based on restrictions from the parent.
 */
static int
cpuset_init(struct cpuset *set, struct cpuset *parent,
    const cpuset_t *mask, struct domainset *domain, cpusetid_t id)
{

        if (domain == NULL)
                domain = parent->cs_domain;
        if (mask == NULL)
                mask = &parent->cs_mask;
        if (!CPU_OVERLAP(&parent->cs_mask, mask))
                return (EDEADLK);
        /* The domain must be prepared ahead of time. */
        if (!domainset_valid(parent->cs_domain, domain))
                return (EDEADLK);
        CPU_COPY(mask, &set->cs_mask);
        LIST_INIT(&set->cs_children);
        refcount_init(&set->cs_ref, 1);
        set->cs_flags = 0;
        mtx_lock_spin(&cpuset_lock);
        set->cs_domain = domain;
        CPU_AND(&set->cs_mask, &set->cs_mask, &parent->cs_mask);
        set->cs_id = id;
        set->cs_parent = cpuset_ref(parent);
        LIST_INSERT_HEAD(&parent->cs_children, set, cs_siblings);
        if (set->cs_id != CPUSET_INVALID)
                LIST_INSERT_HEAD(&cpuset_ids, set, cs_link);
        mtx_unlock_spin(&cpuset_lock);

        return (0);
}

/*
 * Create a new non-anonymous set with the requested parent and mask.  May
 * return failures if the mask is invalid or a new number can not be
 * allocated.
 *
 * If *setp is not NULL, then it will be used as-is.  The caller must take
 * into account that *setp will be inserted at the head of cpuset_ids and
 * plan any potentially conflicting cs_link usage accordingly.
 */
static int
cpuset_create(struct cpuset **setp, struct cpuset *parent, const cpuset_t *mask)
{
        struct cpuset *set;
        cpusetid_t id;
        int error;
        bool dofree;

        id = alloc_unr(cpuset_unr);
        if (id == -1)
                return (ENFILE);
        dofree = (*setp == NULL);
        if (*setp != NULL)
                set = *setp;
        else
                *setp = set = uma_zalloc(cpuset_zone, M_WAITOK | M_ZERO);
        error = cpuset_init(set, parent, mask, NULL, id);
        if (error == 0)
                return (0);
        free_unr(cpuset_unr, id);
        if (dofree)
                uma_zfree(cpuset_zone, set);

        return (error);
}

static void
cpuset_freelist_add(struct setlist *list, int count)
{
        struct cpuset *set;
        int i;

        for (i = 0; i < count; i++) {
                set = uma_zalloc(cpuset_zone, M_ZERO | M_WAITOK);
                LIST_INSERT_HEAD(list, set, cs_link);
        }
}

static void
cpuset_freelist_init(struct setlist *list, int count)
{

        LIST_INIT(list);
        cpuset_freelist_add(list, count);
}

static void
cpuset_freelist_free(struct setlist *list)
{
        struct cpuset *set;

        while ((set = LIST_FIRST(list)) != NULL) {
                LIST_REMOVE(set, cs_link);
                uma_zfree(cpuset_zone, set);
        }
}

static void
domainset_freelist_add(struct domainlist *list, int count)
{
        struct domainset *set;
        int i;

        for (i = 0; i < count; i++) {
                set = uma_zalloc(domainset_zone, M_ZERO | M_WAITOK);
                LIST_INSERT_HEAD(list, set, ds_link);
        }
}

static void
domainset_freelist_init(struct domainlist *list, int count)
{

        LIST_INIT(list);
        domainset_freelist_add(list, count);
}

static void
domainset_freelist_free(struct domainlist *list)
{
        struct domainset *set;

        while ((set = LIST_FIRST(list)) != NULL) {
                LIST_REMOVE(set, ds_link);
                uma_zfree(domainset_zone, set);
        }
}

/* Copy a domainset preserving mask and policy. */
static void
domainset_copy(const struct domainset *from, struct domainset *to)
{

        DOMAINSET_COPY(&from->ds_mask, &to->ds_mask);
        to->ds_policy = from->ds_policy;
        to->ds_prefer = from->ds_prefer;
}

/* Return 1 if mask and policy are equal, otherwise 0. */
static int
domainset_equal(const struct domainset *one, const struct domainset *two)
{

        return (DOMAINSET_CMP(&one->ds_mask, &two->ds_mask) == 0 &&
            one->ds_policy == two->ds_policy &&
            one->ds_prefer == two->ds_prefer);
}

/* Return 1 if child is a valid subset of parent. */
static int
domainset_valid(const struct domainset *parent, const struct domainset *child)
{
        if (child->ds_policy != DOMAINSET_POLICY_PREFER)
                return (DOMAINSET_SUBSET(&parent->ds_mask, &child->ds_mask));
        return (DOMAINSET_ISSET(child->ds_prefer, &parent->ds_mask));
}

static int
domainset_restrict(const struct domainset *parent,
    const struct domainset *child)
{
        if (child->ds_policy != DOMAINSET_POLICY_PREFER)
                return (DOMAINSET_OVERLAP(&parent->ds_mask, &child->ds_mask));
        return (DOMAINSET_ISSET(child->ds_prefer, &parent->ds_mask));
}

/*
 * Lookup or create a domainset.  The key is provided in ds_mask and
 * ds_policy.  If the domainset does not yet exist the storage in
 * 'domain' is used to insert.  Otherwise this storage is freed to the
 * domainset_zone and the existing domainset is returned.
 */
static struct domainset *
_domainset_create(struct domainset *domain, struct domainlist *freelist)
{
        struct domainset *ndomain;
        int i, j;

        KASSERT(domain->ds_cnt <= vm_ndomains,
            ("invalid domain count in domainset %p", domain));
        KASSERT(domain->ds_policy != DOMAINSET_POLICY_PREFER ||
            domain->ds_prefer < vm_ndomains,
            ("invalid preferred domain in domains %p", domain));

        mtx_lock_spin(&cpuset_lock);
        LIST_FOREACH(ndomain, &cpuset_domains, ds_link)
                if (domainset_equal(ndomain, domain))
                        break;
        /*
         * If the domain does not yet exist we insert it and initialize
         * various iteration helpers which are not part of the key.
         */
        if (ndomain == NULL) {
                LIST_INSERT_HEAD(&cpuset_domains, domain, ds_link);
                domain->ds_cnt = DOMAINSET_COUNT(&domain->ds_mask);
                for (i = 0, j = 0; i < DOMAINSET_FLS(&domain->ds_mask); i++)
                        if (DOMAINSET_ISSET(i, &domain->ds_mask))
                                domain->ds_order[j++] = i;
        }
        mtx_unlock_spin(&cpuset_lock);
        if (ndomain == NULL)
                return (domain);
        if (freelist != NULL)
                LIST_INSERT_HEAD(freelist, domain, ds_link);
        else
                uma_zfree(domainset_zone, domain);
        return (ndomain);

}

/*
 * Are any of the domains in the mask empty?  If so, silently
 * remove them and update the domainset accordingly.  If only empty
 * domains are present, we must return failure.
 */
static bool
domainset_empty_vm(struct domainset *domain)
{
        domainset_t empty;
        int i, j;

        DOMAINSET_ZERO(&empty);
        for (i = 0; i < vm_ndomains; i++)
                if (VM_DOMAIN_EMPTY(i))
                        DOMAINSET_SET(i, &empty);
        if (DOMAINSET_SUBSET(&empty, &domain->ds_mask))
                return (true);

        /* Remove empty domains from the set and recompute. */
        DOMAINSET_ANDNOT(&domain->ds_mask, &empty);
        domain->ds_cnt = DOMAINSET_COUNT(&domain->ds_mask);
        for (i = j = 0; i < DOMAINSET_FLS(&domain->ds_mask); i++)
                if (DOMAINSET_ISSET(i, &domain->ds_mask))
                        domain->ds_order[j++] = i;

        /* Convert a PREFER policy referencing an empty domain to RR. */
        if (domain->ds_policy == DOMAINSET_POLICY_PREFER &&
            DOMAINSET_ISSET(domain->ds_prefer, &empty)) {
                domain->ds_policy = DOMAINSET_POLICY_ROUNDROBIN;
                domain->ds_prefer = -1;
        }

        return (false);
}

/*
 * Create or lookup a domainset based on the key held in 'domain'.
 */
struct domainset *
domainset_create(const struct domainset *domain)
{
        struct domainset *ndomain;

        /*
         * Validate the policy.  It must specify a useable policy number with
         * only valid domains.  Preferred must include the preferred domain
         * in the mask.
         */
        if (domain->ds_policy <= DOMAINSET_POLICY_INVALID ||
            domain->ds_policy > DOMAINSET_POLICY_MAX)
                return (NULL);
        if (domain->ds_policy == DOMAINSET_POLICY_PREFER &&
            !DOMAINSET_ISSET(domain->ds_prefer, &domain->ds_mask))
                return (NULL);
        if (!DOMAINSET_SUBSET(&domainset0->ds_mask, &domain->ds_mask))
                return (NULL);
        ndomain = uma_zalloc(domainset_zone, M_WAITOK | M_ZERO);
        domainset_copy(domain, ndomain);
        return _domainset_create(ndomain, NULL);
}

/*
 * Update thread domainset pointers.
 */
static void
domainset_notify(void)
{
        struct thread *td;
        struct proc *p;

        sx_slock(&allproc_lock);
        FOREACH_PROC_IN_SYSTEM(p) {
                PROC_LOCK(p);
                if (p->p_state == PRS_NEW) {
                        PROC_UNLOCK(p);
                        continue;
                }
                FOREACH_THREAD_IN_PROC(p, td) {
                        thread_lock(td);
                        td->td_domain.dr_policy = td->td_cpuset->cs_domain;
                        thread_unlock(td);
                }
                PROC_UNLOCK(p);
        }
        sx_sunlock(&allproc_lock);
        kernel_object->domain.dr_policy = cpuset_kernel->cs_domain;
}

/*
 * Create a new set that is a subset of a parent.
 */
static struct domainset *
domainset_shadow(const struct domainset *pdomain,
    const struct domainset *domain, struct domainlist *freelist)
{
        struct domainset *ndomain;

        ndomain = LIST_FIRST(freelist);
        LIST_REMOVE(ndomain, ds_link);

        /*
         * Initialize the key from the request.
         */
        domainset_copy(domain, ndomain);

        /*
         * Restrict the key by the parent.
         */
        DOMAINSET_AND(&ndomain->ds_mask, &pdomain->ds_mask);

        return _domainset_create(ndomain, freelist);
}

/*
 * Recursively check for errors that would occur from applying mask to
 * the tree of sets starting at 'set'.  Checks for sets that would become
 * empty as well as RDONLY flags.
 */
static int
cpuset_testupdate(struct cpuset *set, cpuset_t *mask, int augment_mask)
{
        struct cpuset *nset;
        cpuset_t newmask;
        int error;

        mtx_assert(&cpuset_lock, MA_OWNED);
        if (set->cs_flags & CPU_SET_RDONLY)
                return (EPERM);
        if (augment_mask) {
                CPU_AND(&newmask, &set->cs_mask, mask);
        } else
                CPU_COPY(mask, &newmask);

        if (CPU_EMPTY(&newmask))
                return (EDEADLK);
        error = 0;
        LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
                if ((error = cpuset_testupdate(nset, &newmask, 1)) != 0)
                        break;
        return (error);
}

/*
 * Applies the mask 'mask' without checking for empty sets or permissions.
 */
static void
cpuset_update(struct cpuset *set, cpuset_t *mask)
{
        struct cpuset *nset;

        mtx_assert(&cpuset_lock, MA_OWNED);
        CPU_AND(&set->cs_mask, &set->cs_mask, mask);
        LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
                cpuset_update(nset, &set->cs_mask);

        return;
}

/*
 * Modify the set 'set' to use a copy of the mask provided.  Apply this new
 * mask to restrict all children in the tree.  Checks for validity before
 * applying the changes.
 */
static int
cpuset_modify(struct cpuset *set, cpuset_t *mask)
{
        struct cpuset *root;
        int error;

        error = priv_check(curthread, PRIV_SCHED_CPUSET);
        if (error)
                return (error);
        /*
         * In case we are called from within the jail,
         * we do not allow modifying the dedicated root
         * cpuset of the jail but may still allow to
         * change child sets, including subordinate jails'
         * roots.
         */
        if ((set->cs_flags & CPU_SET_ROOT) != 0 &&
            jailed(curthread->td_ucred) &&
            set == curthread->td_ucred->cr_prison->pr_cpuset)
                return (EPERM);
        /*
         * Verify that we have access to this set of
         * cpus.
         */
        if ((set->cs_flags & (CPU_SET_ROOT | CPU_SET_RDONLY)) == CPU_SET_ROOT) {
                KASSERT(set->cs_parent != NULL,
                    ("jail.cpuset=%d is not a proper child of parent jail's root.",
                    set->cs_id));

                /*
                 * cpuset_getroot() cannot work here due to how top-level jail
                 * roots are constructed.  Top-level jails are parented to
                 * thread0's cpuset (i.e. cpuset 1) rather than the system root.
                 */
                root = set->cs_parent;
        } else {
                root = cpuset_getroot(set);
        }
        mtx_lock_spin(&cpuset_lock);
        if (root && !CPU_SUBSET(&root->cs_mask, mask)) {
                error = EINVAL;
                goto out;
        }
        error = cpuset_testupdate(set, mask, 0);
        if (error)
                goto out;
        CPU_COPY(mask, &set->cs_mask);
        cpuset_update(set, mask);
out:
        mtx_unlock_spin(&cpuset_lock);

        return (error);
}

/*
 * Recursively check for errors that would occur from applying mask to
 * the tree of sets starting at 'set'.  Checks for sets that would become
 * empty as well as RDONLY flags.
 */
static int
cpuset_testupdate_domain(struct cpuset *set, struct domainset *dset,
    struct domainset *orig, int *count, int augment_mask __unused)
{
        struct cpuset *nset;
        struct domainset *domain;
        struct domainset newset;
        int error;

        mtx_assert(&cpuset_lock, MA_OWNED);
        if (set->cs_flags & CPU_SET_RDONLY)
                return (EPERM);
        domain = set->cs_domain;
        domainset_copy(domain, &newset);
        if (!domainset_equal(domain, orig)) {
                if (!domainset_restrict(domain, dset))
                        return (EDEADLK);
                DOMAINSET_AND(&newset.ds_mask, &dset->ds_mask);
                /* Count the number of domains that are changing. */
                (*count)++;
        }
        error = 0;
        LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
                if ((error = cpuset_testupdate_domain(nset, &newset, domain,
                    count, 1)) != 0)
                        break;
        return (error);
}

/*
 * Applies the mask 'mask' without checking for empty sets or permissions.
 */
static void
cpuset_update_domain(struct cpuset *set, struct domainset *domain,
    struct domainset *orig, struct domainlist *domains)
{
        struct cpuset *nset;

        mtx_assert(&cpuset_lock, MA_OWNED);
        /*
         * If this domainset has changed from the parent we must calculate
         * a new set.  Otherwise it simply inherits from the parent.  When
         * we inherit from the parent we get a new mask and policy.  If the
         * set is modified from the parent we keep the policy and only
         * update the mask.
         */
        if (set->cs_domain != orig) {
                orig = set->cs_domain;
                set->cs_domain = domainset_shadow(domain, orig, domains);
        } else
                set->cs_domain = domain;
        LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
                cpuset_update_domain(nset, set->cs_domain, orig, domains);

        return;
}

/*
 * Modify the set 'set' to use a copy the domainset provided.  Apply this new
 * mask to restrict all children in the tree.  Checks for validity before
 * applying the changes.
 */
static int
cpuset_modify_domain(struct cpuset *set, struct domainset *domain)
{
        struct domainlist domains;
        struct domainset temp;
        struct domainset *dset;
        struct cpuset *root;
        int ndomains, needed;
        int error;

        error = priv_check(curthread, PRIV_SCHED_CPUSET);
        if (error)
                return (error);
        /*
         * In case we are called from within the jail
         * we do not allow modifying the dedicated root
         * cpuset of the jail but may still allow to
         * change child sets.
         */
        if (jailed(curthread->td_ucred) &&
            set->cs_flags & CPU_SET_ROOT)
                return (EPERM);
        domainset_freelist_init(&domains, 0);
        domain = domainset_create(domain);
        ndomains = 0;

        mtx_lock_spin(&cpuset_lock);
        for (;;) {
                root = cpuset_getroot(set);
                dset = root->cs_domain;
                /*
                 * Verify that we have access to this set of domains.
                 */
                if (!domainset_valid(dset, domain)) {
                        error = EINVAL;
                        goto out;
                }
                /*
                 * If applying prefer we keep the current set as the fallback.
                 */
                if (domain->ds_policy == DOMAINSET_POLICY_PREFER)
                        DOMAINSET_COPY(&set->cs_domain->ds_mask,
                            &domain->ds_mask);
                /*
                 * Determine whether we can apply this set of domains and
                 * how many new domain structures it will require.
                 */
                domainset_copy(domain, &temp);
                needed = 0;
                error = cpuset_testupdate_domain(set, &temp, set->cs_domain,
                    &needed, 0);
                if (error)
                        goto out;
                if (ndomains >= needed)
                        break;

                /* Dropping the lock; we'll need to re-evaluate again. */
                mtx_unlock_spin(&cpuset_lock);
                domainset_freelist_add(&domains, needed - ndomains);
                ndomains = needed;
                mtx_lock_spin(&cpuset_lock);
        }
        dset = set->cs_domain;
        cpuset_update_domain(set, domain, dset, &domains);
out:
        mtx_unlock_spin(&cpuset_lock);
        domainset_freelist_free(&domains);
        if (error == 0)
                domainset_notify();

        return (error);
}

/*
 * Resolve the 'which' parameter of several cpuset apis.
 *
 * For WHICH_PID and WHICH_TID return a locked proc and valid proc/tid.  Also
 * checks for permission via p_cansched().
 *
 * For WHICH_SET returns a valid set with a new reference.
 *
 * -1 may be supplied for any argument to mean the current proc/thread or
 * the base set of the current thread.  May fail with ESRCH/EPERM.
 */
int
cpuset_which(cpuwhich_t which, id_t id, struct proc **pp, struct thread **tdp,
    struct cpuset **setp)
{
        struct cpuset *set;
        struct thread *td;
        struct proc *p;
        int error;

        *pp = p = NULL;
        *tdp = td = NULL;
        *setp = set = NULL;
        switch (which) {
        case CPU_WHICH_PID:
                if (id == -1) {
                        PROC_LOCK(curproc);
                        p = curproc;
                        break;
                }
                if ((p = pfind(id)) == NULL)
                        return (ESRCH);
                break;
        case CPU_WHICH_TID:
                if (id == -1) {
                        PROC_LOCK(curproc);
                        p = curproc;
                        td = curthread;
                        break;
                }
                td = tdfind(id, -1);
                if (td == NULL)
                        return (ESRCH);
                p = td->td_proc;
                break;
        case CPU_WHICH_TIDPID:
                if (id == -1) {
                        PROC_LOCK(curproc);
                        td = curthread;
                        p = curproc;
                } else if (id > PID_MAX) {
                        td = tdfind(id, -1);
                        if (td == NULL)
                                return (ESRCH);
                        p = td->td_proc;
                } else {
                        p = pfind(id);
                        if (p == NULL)
                                return (ESRCH);
                }
                break;
        case CPU_WHICH_CPUSET:
                if (id == -1) {
                        thread_lock(curthread);
                        set = cpuset_refbase(curthread->td_cpuset);
                        thread_unlock(curthread);
                } else
                        set = cpuset_lookup(id, curthread);
                if (set) {
                        *setp = set;
                        return (0);
                }
                return (ESRCH);
        case CPU_WHICH_JAIL:
        {
                /* Find `set' for prison with given id. */
                struct prison *pr;

                sx_slock(&allprison_lock);
                pr = prison_find_child(curthread->td_ucred->cr_prison, id);
                sx_sunlock(&allprison_lock);
                if (pr == NULL)
                        return (ESRCH);
                cpuset_ref(pr->pr_cpuset);
                *setp = pr->pr_cpuset;
                mtx_unlock(&pr->pr_mtx);
                return (0);
        }
        case CPU_WHICH_IRQ:
        case CPU_WHICH_DOMAIN:
                return (0);
        default:
                return (EINVAL);
        }
        error = p_cansched(curthread, p);
        if (error) {
                PROC_UNLOCK(p);
                return (error);
        }
        if (td == NULL)
                td = FIRST_THREAD_IN_PROC(p);
        *pp = p;
        *tdp = td;
        return (0);
}

static int
cpuset_which2(cpuwhich_t *which, id_t id, struct proc **pp, struct thread **tdp,
    struct cpuset **setp)
{

        if (*which == CPU_WHICH_TIDPID) {
                if (id == -1 || id > PID_MAX)
                        *which = CPU_WHICH_TID;
                else
                        *which = CPU_WHICH_PID;
        }
        return (cpuset_which(*which, id, pp, tdp, setp));
}

static int
cpuset_testshadow(struct cpuset *set, const cpuset_t *mask,
    const struct domainset *domain)
{
        struct cpuset *parent;
        struct domainset *dset;

        parent = cpuset_getbase(set);
        /*
         * If we are restricting a cpu mask it must be a subset of the
         * parent or invalid CPUs have been specified.
         */
        if (mask != NULL && !CPU_SUBSET(&parent->cs_mask, mask))
                return (EINVAL);

        /*
         * If we are restricting a domain mask it must be a subset of the
         * parent or invalid domains have been specified.
         */
        dset = parent->cs_domain;
        if (domain != NULL && !domainset_valid(dset, domain))
                return (EINVAL);

        return (0);
}

/*
 * Create an anonymous set with the provided mask in the space provided by
 * 'nset'.  If the passed in set is anonymous we use its parent otherwise
 * the new set is a child of 'set'.
 */
static int
cpuset_shadow(struct cpuset *set, struct cpuset **nsetp,
   const cpuset_t *mask, const struct domainset *domain,
   struct setlist *cpusets, struct domainlist *domains)
{
        struct cpuset *parent;
        struct cpuset *nset;
        struct domainset *dset;
        struct domainset *d;
        int error;

        error = cpuset_testshadow(set, mask, domain);
        if (error)
                return (error);

        parent = cpuset_getbase(set);
        dset = parent->cs_domain;
        if (mask == NULL)
                mask = &set->cs_mask;
        if (domain != NULL)
                d = domainset_shadow(dset, domain, domains);
        else
                d = set->cs_domain;
        nset = LIST_FIRST(cpusets);
        error = cpuset_init(nset, parent, mask, d, CPUSET_INVALID);
        if (error == 0) {
                LIST_REMOVE(nset, cs_link);
                *nsetp = nset;
        }
        return (error);
}

static struct cpuset *
cpuset_update_thread(struct thread *td, struct cpuset *nset)
{
        struct cpuset *tdset;

        tdset = td->td_cpuset;
        td->td_cpuset = nset;
        td->td_domain.dr_policy = nset->cs_domain;
        sched_affinity(td);

        return (tdset);
}

static int
cpuset_setproc_test_maskthread(struct cpuset *tdset, cpuset_t *mask,
    struct domainset *domain)
{
        struct cpuset *parent;

        parent = cpuset_getbase(tdset);
        if (mask == NULL)
                mask = &tdset->cs_mask;
        if (domain == NULL)
                domain = tdset->cs_domain;
        return cpuset_testshadow(parent, mask, domain);
}

static int
cpuset_setproc_maskthread(struct cpuset *tdset, cpuset_t *mask,
    struct domainset *domain, struct cpuset **nsetp,
    struct setlist *freelist, struct domainlist *domainlist)
{
        struct cpuset *parent;

        parent = cpuset_getbase(tdset);
        if (mask == NULL)
                mask = &tdset->cs_mask;
        if (domain == NULL)
                domain = tdset->cs_domain;
        return cpuset_shadow(parent, nsetp, mask, domain, freelist,
            domainlist);
}

static int
cpuset_setproc_setthread_mask(struct cpuset *tdset, struct cpuset *set,
    cpuset_t *mask, struct domainset *domain)
{
        struct cpuset *parent;

        parent = cpuset_getbase(tdset);

        /*
         * If the thread restricted its mask then apply that same
         * restriction to the new set, otherwise take it wholesale.
         */
        if (CPU_CMP(&tdset->cs_mask, &parent->cs_mask) != 0) {
                CPU_AND(mask, &tdset->cs_mask, &set->cs_mask);
        } else
                CPU_COPY(&set->cs_mask, mask);

        /*
         * If the thread restricted the domain then we apply the
         * restriction to the new set but retain the policy.
         */
        if (tdset->cs_domain != parent->cs_domain) {
                domainset_copy(tdset->cs_domain, domain);
                DOMAINSET_AND(&domain->ds_mask, &set->cs_domain->ds_mask);
        } else
                domainset_copy(set->cs_domain, domain);

        if (CPU_EMPTY(mask) || DOMAINSET_EMPTY(&domain->ds_mask))
                return (EDEADLK);

        return (0);
}

static int
cpuset_setproc_test_setthread(struct cpuset *tdset, struct cpuset *set)
{
        struct domainset domain;
        cpuset_t mask;

        if (tdset->cs_id != CPUSET_INVALID)
                return (0);
        return cpuset_setproc_setthread_mask(tdset, set, &mask, &domain);
}

static int
cpuset_setproc_setthread(struct cpuset *tdset, struct cpuset *set,
    struct cpuset **nsetp, struct setlist *freelist,
    struct domainlist *domainlist)
{
        struct domainset domain;
        cpuset_t mask;
        int error;

        /*
         * If we're replacing on a thread that has not constrained the
         * original set we can simply accept the new set.
         */
        if (tdset->cs_id != CPUSET_INVALID) {
                *nsetp = cpuset_ref(set);
                return (0);
        }
        error = cpuset_setproc_setthread_mask(tdset, set, &mask, &domain);
        if (error)
                return (error);

        return cpuset_shadow(set, nsetp, &mask, &domain, freelist,
            domainlist);
}

static int
cpuset_setproc_newbase(struct thread *td, struct cpuset *set,
    struct cpuset *nroot, struct cpuset **nsetp,
    struct setlist *cpusets, struct domainlist *domainlist)
{
        struct domainset ndomain;
        cpuset_t nmask;
        struct cpuset *pbase;
        int error;

        pbase = cpuset_getbase(td->td_cpuset);

        /* Copy process mask, then further apply the new root mask. */
        CPU_AND(&nmask, &pbase->cs_mask, &nroot->cs_mask);

        domainset_copy(pbase->cs_domain, &ndomain);
        DOMAINSET_AND(&ndomain.ds_mask, &set->cs_domain->ds_mask);

        /* Policy is too restrictive, will not work. */
        if (CPU_EMPTY(&nmask) || DOMAINSET_EMPTY(&ndomain.ds_mask))
                return (EDEADLK);

        /*
         * Remove pbase from the freelist in advance, it'll be pushed to
         * cpuset_ids on success.  We assume here that cpuset_create() will not
         * touch pbase on failure, and we just enqueue it back to the freelist
         * to remain in a consistent state.
         */
        pbase = LIST_FIRST(cpusets);
        LIST_REMOVE(pbase, cs_link);
        error = cpuset_create(&pbase, set, &nmask);
        if (error != 0) {
                LIST_INSERT_HEAD(cpusets, pbase, cs_link);
                return (error);
        }

        /* Duplicates some work from above... oh well. */
        pbase->cs_domain = domainset_shadow(set->cs_domain, &ndomain,
            domainlist);
        *nsetp = pbase;
        return (0);
}

/*
 * Handle four cases for updating an entire process.
 *
 * 1) Set is non-null and the process is not rebasing onto a new root.  This
 *    reparents all anonymous sets to the provided set and replaces all
 *    non-anonymous td_cpusets with the provided set.
 * 2) Set is non-null and the process is rebasing onto a new root.  This
 *    creates a new base set if the process previously had its own base set,
 *    then reparents all anonymous sets either to that set or the provided set
 *    if one was not created.  Non-anonymous sets are similarly replaced.
 * 3) Mask is non-null.  This replaces or creates anonymous sets for every
 *    thread with the existing base as a parent.
 * 4) domain is non-null.  This creates anonymous sets for every thread
 *    and replaces the domain set.
 *
 * This is overly complicated because we can't allocate while holding a 
 * spinlock and spinlocks must be held while changing and examining thread
 * state.
 */
static int
cpuset_setproc(pid_t pid, struct cpuset *set, cpuset_t *mask,
    struct domainset *domain, bool rebase)
{
        struct setlist freelist;
        struct setlist droplist;
        struct domainlist domainlist;
        struct cpuset *base, *nset, *nroot, *tdroot;
        struct thread *td;
        struct proc *p;
        int needed;
        int nfree;
        int error;

        /*
         * The algorithm requires two passes due to locking considerations.
         * 
         * 1) Lookup the process and acquire the locks in the required order.
         * 2) If enough cpusets have not been allocated release the locks and
         *    allocate them.  Loop.
         */
        cpuset_freelist_init(&freelist, 1);
        domainset_freelist_init(&domainlist, 1);
        nfree = 1;
        LIST_INIT(&droplist);
        nfree = 0;
        base = set;
        nroot = NULL;
        if (set != NULL)
                nroot = cpuset_getroot(set);
        for (;;) {
                error = cpuset_which(CPU_WHICH_PID, pid, &p, &td, &nset);
                if (error)
                        goto out;
                tdroot = cpuset_getroot(td->td_cpuset);
                needed = p->p_numthreads;
                if (set != NULL && rebase && tdroot != nroot)
                        needed++;
                if (nfree >= needed)
                        break;
                PROC_UNLOCK(p);
                if (nfree < needed) {
                        cpuset_freelist_add(&freelist, needed - nfree);
                        domainset_freelist_add(&domainlist, needed - nfree);
                        nfree = needed;
                }
        }
        PROC_LOCK_ASSERT(p, MA_OWNED);

        /*
         * If we're changing roots and the root set is what has been specified
         * as the parent, then we'll check if the process was previously using
         * the root set and, if it wasn't, create a new base with the process's
         * mask applied to it.
         *
         * If the new root is incompatible with the existing mask, then we allow
         * the process to take on the new root if and only if they have
         * privilege to widen their mask anyways.  Unprivileged processes get
         * rejected with EDEADLK.
         */
        if (set != NULL && rebase && nroot != tdroot) {
                cpusetid_t base_id, root_id;

                root_id = td->td_ucred->cr_prison->pr_cpuset->cs_id;
                base_id = cpuset_getbase(td->td_cpuset)->cs_id;

                if (base_id != root_id) {
                        error = cpuset_setproc_newbase(td, set, nroot, &base,
                            &freelist, &domainlist);
                        if (error == EDEADLK &&
                            priv_check(td, PRIV_SCHED_CPUSET) == 0)
                                error = 0;
                        if (error != 0)
                                goto unlock_out;
                }
        }

        /*
         * Now that the appropriate locks are held and we have enough cpusets,
         * make sure the operation will succeed before applying changes. The
         * proc lock prevents td_cpuset from changing between calls.
         */
        error = 0;
        FOREACH_THREAD_IN_PROC(p, td) {
                thread_lock(td);
                if (set != NULL)
                        error = cpuset_setproc_test_setthread(td->td_cpuset,
                            base);
                else
                        error = cpuset_setproc_test_maskthread(td->td_cpuset,
                            mask, domain);
                thread_unlock(td);
                if (error)
                        goto unlock_out;
        }
        /*
         * Replace each thread's cpuset while using deferred release.  We
         * must do this because the thread lock must be held while operating
         * on the thread and this limits the type of operations allowed.
         */
        FOREACH_THREAD_IN_PROC(p, td) {
                thread_lock(td);
                if (set != NULL)
                        error = cpuset_setproc_setthread(td->td_cpuset, base,
                            &nset, &freelist, &domainlist);
                else
                        error = cpuset_setproc_maskthread(td->td_cpuset, mask,
                            domain, &nset, &freelist, &domainlist);
                if (error) {
                        thread_unlock(td);
                        break;
                }
                cpuset_rel_defer(&droplist, cpuset_update_thread(td, nset));
                thread_unlock(td);
        }
unlock_out:
        PROC_UNLOCK(p);
out:
        if (base != NULL && base != set)
                cpuset_rel(base);
        while ((nset = LIST_FIRST(&droplist)) != NULL)
                cpuset_rel_complete(nset);
        cpuset_freelist_free(&freelist);
        domainset_freelist_free(&domainlist);
        return (error);
}

static int
bitset_strprint(char *buf, size_t bufsiz, const struct bitset *set, int setlen)
{
        size_t bytes;
        int i, once;
        char *p;

        once = 0;
        p = buf;
        for (i = 0; i < __bitset_words(setlen); i++) {
                if (once != 0) {
                        if (bufsiz < 1)
                                return (0);
                        *p = ',';
                        p++;
                        bufsiz--;
                } else
                        once = 1;
                if (bufsiz < sizeof(__STRING(ULONG_MAX)))
                        return (0);
                bytes = snprintf(p, bufsiz, "%lx", set->__bits[i]);
                p += bytes;
                bufsiz -= bytes;
        }
        return (p - buf);
}

static int
bitset_strscan(struct bitset *set, int setlen, const char *buf)
{
        int i, ret;
        const char *p;

        BIT_ZERO(setlen, set);
        p = buf;
        for (i = 0; i < __bitset_words(setlen); i++) {
                if (*p == ',') {
                        p++;
                        continue;
                }
                ret = sscanf(p, "%lx", &set->__bits[i]);
                if (ret == 0 || ret == -1)
                        break;
                while (isxdigit(*p))
                        p++;
        }
        return (p - buf);
}

/*
 * Return a string representing a valid layout for a cpuset_t object.
 * It expects an incoming buffer at least sized as CPUSETBUFSIZ.
 */
char *
cpusetobj_strprint(char *buf, const cpuset_t *set)
{

        bitset_strprint(buf, CPUSETBUFSIZ, (const struct bitset *)set,
            CPU_SETSIZE);
        return (buf);
}

/*
 * Build a valid cpuset_t object from a string representation.
 * It expects an incoming buffer at least sized as CPUSETBUFSIZ.
 */
int
cpusetobj_strscan(cpuset_t *set, const char *buf)
{
        char p;

        if (strlen(buf) > CPUSETBUFSIZ - 1)
                return (-1);

        p = buf[bitset_strscan((struct bitset *)set, CPU_SETSIZE, buf)];
        if (p != '\0')
                return (-1);

        return (0);
}

/*
 * Handle a domainset specifier in the sysctl tree.  A poiner to a pointer to
 * a domainset is in arg1.  If the user specifies a valid domainset the
 * pointer is updated.
 *
 * Format is:
 * hex mask word 0,hex mask word 1,...:decimal policy:decimal preferred
 */
int
sysctl_handle_domainset(SYSCTL_HANDLER_ARGS)
{
        char buf[DOMAINSETBUFSIZ];
        struct domainset *dset;
        struct domainset key;
        int policy, prefer, error;
        char *p;

        dset = *(struct domainset **)arg1;
        error = 0;

        if (dset != NULL) {
                p = buf + bitset_strprint(buf, DOMAINSETBUFSIZ,
                    (const struct bitset *)&dset->ds_mask, DOMAINSET_SETSIZE);
                sprintf(p, ":%d:%d", dset->ds_policy, dset->ds_prefer);
        } else
                sprintf(buf, "<NULL>");
        error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
        if (error != 0 || req->newptr == NULL)
                return (error);

        /*
         * Read in and validate the string.
         */
        memset(&key, 0, sizeof(key));
        p = &buf[bitset_strscan((struct bitset *)&key.ds_mask,
            DOMAINSET_SETSIZE, buf)];
        if (p == buf)
                return (EINVAL);
        if (sscanf(p, ":%d:%d", &policy, &prefer) != 2)
                return (EINVAL);
        key.ds_policy = policy;
        key.ds_prefer = prefer;

        /* Domainset_create() validates the policy.*/
        dset = domainset_create(&key);
        if (dset == NULL)
                return (EINVAL);
        *(struct domainset **)arg1 = dset;

        return (error);
}

/*
 * Apply an anonymous mask or a domain to a single thread.
 */
static int
_cpuset_setthread(lwpid_t id, cpuset_t *mask, struct domainset *domain)
{
        struct setlist cpusets;
        struct domainlist domainlist;
        struct cpuset *nset;
        struct cpuset *set;
        struct thread *td;
        struct proc *p;
        int error;

        cpuset_freelist_init(&cpusets, 1);
        domainset_freelist_init(&domainlist, domain != NULL);
        error = cpuset_which(CPU_WHICH_TID, id, &p, &td, &set);
        if (error)
                goto out;
        set = NULL;
        thread_lock(td);
        error = cpuset_shadow(td->td_cpuset, &nset, mask, domain,
            &cpusets, &domainlist);
        if (error == 0)
                set = cpuset_update_thread(td, nset);
        thread_unlock(td);
        PROC_UNLOCK(p);
        if (set)
                cpuset_rel(set);
out:
        cpuset_freelist_free(&cpusets);
        domainset_freelist_free(&domainlist);
        return (error);
}

/*
 * Apply an anonymous mask to a single thread.
 */
int
cpuset_setthread(lwpid_t id, cpuset_t *mask)
{

        return _cpuset_setthread(id, mask, NULL);
}

/*
 * Apply new cpumask to the ithread.
 */
int
cpuset_setithread(lwpid_t id, int cpu)
{
        cpuset_t mask;

        CPU_ZERO(&mask);
        if (cpu == NOCPU)
                CPU_COPY(cpuset_root, &mask);
        else
                CPU_SET(cpu, &mask);
        return _cpuset_setthread(id, &mask, NULL);
}

/*
 * Initialize static domainsets after NUMA information is available.  This is
 * called before memory allocators are initialized.
 */
void
domainset_init(void)
{
        struct domainset *dset;
        int i;

        dset = &domainset_firsttouch;
        DOMAINSET_COPY(&all_domains, &dset->ds_mask);
        dset->ds_policy = DOMAINSET_POLICY_FIRSTTOUCH;
        dset->ds_prefer = -1;
        _domainset_create(dset, NULL);

        dset = &domainset_interleave;
        DOMAINSET_COPY(&all_domains, &dset->ds_mask);
        dset->ds_policy = DOMAINSET_POLICY_INTERLEAVE;
        dset->ds_prefer = -1;
        _domainset_create(dset, NULL);

        dset = &domainset_roundrobin;
        DOMAINSET_COPY(&all_domains, &dset->ds_mask);
        dset->ds_policy = DOMAINSET_POLICY_ROUNDROBIN;
        dset->ds_prefer = -1;
        _domainset_create(dset, NULL);

        for (i = 0; i < vm_ndomains; i++) {
                dset = &domainset_fixed[i];
                DOMAINSET_ZERO(&dset->ds_mask);
                DOMAINSET_SET(i, &dset->ds_mask);
                dset->ds_policy = DOMAINSET_POLICY_ROUNDROBIN;
                _domainset_create(dset, NULL);

                dset = &domainset_prefer[i];
                DOMAINSET_COPY(&all_domains, &dset->ds_mask);
                dset->ds_policy = DOMAINSET_POLICY_PREFER;
                dset->ds_prefer = i;
                _domainset_create(dset, NULL);
        }
}

/*
 * Define the domainsets for cpuset 0, 1 and cpuset 2.
 */
void
domainset_zero(void)
{
        struct domainset *dset, *tmp;

        mtx_init(&cpuset_lock, "cpuset", NULL, MTX_SPIN | MTX_RECURSE);

        domainset0 = &domainset_firsttouch;
        curthread->td_domain.dr_policy = domainset0;

        domainset2 = &domainset_interleave;
        kernel_object->domain.dr_policy = domainset2;

        /* Remove empty domains from the global policies. */
        LIST_FOREACH_SAFE(dset, &cpuset_domains, ds_link, tmp)
                if (domainset_empty_vm(dset))
                        LIST_REMOVE(dset, ds_link);
}

/*
 * Creates system-wide cpusets and the cpuset for thread0 including three
 * sets:
 * 
 * 0 - The root set which should represent all valid processors in the
 *     system.  This set is immutable.
 * 1 - The default set which all processes are a member of until changed.
 *     This allows an administrator to move all threads off of given cpus to
 *     dedicate them to high priority tasks or save power etc.
 * 2 - The kernel set which allows restriction and policy to be applied only
 *     to kernel threads and the kernel_object.
 */
struct cpuset *
cpuset_thread0(void)
{
        struct cpuset *set;
        int i;
        int error __unused;

        cpuset_zone = uma_zcreate("cpuset", sizeof(struct cpuset), NULL, NULL,
            NULL, NULL, UMA_ALIGN_CACHE, 0);
        domainset_zone = uma_zcreate("domainset", sizeof(struct domainset),
            NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);

        /*
         * Create the root system set (0) for the whole machine.  Doesn't use
         * cpuset_create() due to NULL parent.
         */
        set = uma_zalloc(cpuset_zone, M_WAITOK | M_ZERO);
        CPU_COPY(&all_cpus, &set->cs_mask);
        LIST_INIT(&set->cs_children);
        LIST_INSERT_HEAD(&cpuset_ids, set, cs_link);
        refcount_init(&set->cs_ref, 1);
        set->cs_flags = CPU_SET_ROOT | CPU_SET_RDONLY;
        set->cs_domain = domainset0;
        cpuset_zero = set;
        cpuset_root = &set->cs_mask;

        /*
         * Now derive a default (1), modifiable set from that to give out.
         */
        set = uma_zalloc(cpuset_zone, M_WAITOK | M_ZERO);
        error = cpuset_init(set, cpuset_zero, NULL, NULL, 1);
        KASSERT(error == 0, ("Error creating default set: %d\n", error));
        cpuset_default = set;
        /*
         * Create the kernel set (2).
         */
        set = uma_zalloc(cpuset_zone, M_WAITOK | M_ZERO);
        error = cpuset_init(set, cpuset_zero, NULL, NULL, 2);
        KASSERT(error == 0, ("Error creating kernel set: %d\n", error));
        set->cs_domain = domainset2;
        cpuset_kernel = set;

        /*
         * Initialize the unit allocator. 0 and 1 are allocated above.
         */
        cpuset_unr = new_unrhdr(3, INT_MAX, NULL);

        /*
         * If MD code has not initialized per-domain cpusets, place all
         * CPUs in domain 0.
         */
        for (i = 0; i < MAXMEMDOM; i++)
                if (!CPU_EMPTY(&cpuset_domain[i]))
                        goto domains_set;
        CPU_COPY(&all_cpus, &cpuset_domain[0]);
domains_set:

        return (cpuset_default);
}

void
cpuset_kernthread(struct thread *td)
{
        struct cpuset *set;

        thread_lock(td);
        set = td->td_cpuset;
        td->td_cpuset = cpuset_ref(cpuset_kernel);
        thread_unlock(td);
        cpuset_rel(set);
}

/*
 * Create a cpuset, which would be cpuset_create() but
 * mark the new 'set' as root.
 *
 * We are not going to reparent the td to it.  Use cpuset_setproc_update_set()
 * for that.
 *
 * In case of no error, returns the set in *setp locked with a reference.
 */
int
cpuset_create_root(struct prison *pr, struct cpuset **setp)
{
        struct cpuset *set;
        int error;

        KASSERT(pr != NULL, ("[%s:%d] invalid pr", __func__, __LINE__));
        KASSERT(setp != NULL, ("[%s:%d] invalid setp", __func__, __LINE__));

        set = NULL;
        error = cpuset_create(&set, pr->pr_cpuset, &pr->pr_cpuset->cs_mask);
        if (error)
                return (error);

        KASSERT(set != NULL, ("[%s:%d] cpuset_create returned invalid data",
            __func__, __LINE__));

        /* Mark the set as root. */
        set->cs_flags |= CPU_SET_ROOT;
        *setp = set;

        return (0);
}

int
cpuset_setproc_update_set(struct proc *p, struct cpuset *set)
{
        int error;

        KASSERT(p != NULL, ("[%s:%d] invalid proc", __func__, __LINE__));
        KASSERT(set != NULL, ("[%s:%d] invalid set", __func__, __LINE__));

        cpuset_ref(set);
        error = cpuset_setproc(p->p_pid, set, NULL, NULL, true);
        if (error)
                return (error);
        cpuset_rel(set);
        return (0);
}

/*
 * In Capability mode, the only accesses that are permitted are to the current
 * thread and process' CPU and domain sets.
 */
static int
cpuset_check_capabilities(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id)
{
        if (IN_CAPABILITY_MODE(td)) {
                if (level != CPU_LEVEL_WHICH)
                        return (ECAPMODE);
                if (which != CPU_WHICH_TID && which != CPU_WHICH_PID &&
                    which != CPU_WHICH_TIDPID)
                        return (ECAPMODE);
                if (id != -1 && which == CPU_WHICH_TIDPID &&
                    id != td->td_tid && id != td->td_proc->p_pid)
                        return (ECAPMODE);
                if (id != -1 &&
                    !(which == CPU_WHICH_TID && id == td->td_tid) &&
                    !(which == CPU_WHICH_PID && id == td->td_proc->p_pid))
                        return (ECAPMODE);
        }
        return (0);
}

#if defined(__powerpc__)
/*
 * TODO: At least powerpc64 and powerpc64le kernels panic with
 * exception 0x480 (instruction segment exception) when copyin/copyout,
 * are set as a function pointer in cpuset_copy_cb struct and called by
 * an external module (like pfsync). Tip: copyin/copyout have an ifunc
 * resolver function.
 *
 * Bisect of LLVM shows that the behavior changed on LLVM 10.0 with
 * https://reviews.llvm.org/rGdc06b0bc9ad055d06535462d91bfc2a744b2f589
 *
 * This is a hack/workaround while problem is being discussed with LLVM
 * community
 */
static int
cpuset_copyin(const void *uaddr, void *kaddr, size_t len)
{
        return(copyin(uaddr, kaddr, len));
}

static int
cpuset_copyout(const void *kaddr, void *uaddr, size_t len)
{
        return(copyout(kaddr, uaddr, len));
}

static const struct cpuset_copy_cb copy_set = {
        .cpuset_copyin = cpuset_copyin,
        .cpuset_copyout = cpuset_copyout
};
#else
static const struct cpuset_copy_cb copy_set = {
        .cpuset_copyin = copyin,
        .cpuset_copyout = copyout
};
#endif

#ifndef _SYS_SYSPROTO_H_
struct cpuset_args {
        cpusetid_t      *setid;
};
#endif
int
sys_cpuset(struct thread *td, struct cpuset_args *uap)
{
        struct cpuset *root;
        struct cpuset *set;
        int error;

        thread_lock(td);
        root = cpuset_refroot(td->td_cpuset);
        thread_unlock(td);
        set = NULL;
        error = cpuset_create(&set, root, &root->cs_mask);
        cpuset_rel(root);
        if (error)
                return (error);
        error = copyout(&set->cs_id, uap->setid, sizeof(set->cs_id));
        if (error == 0)
                error = cpuset_setproc(-1, set, NULL, NULL, false);
        cpuset_rel(set);
        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct cpuset_setid_args {
        cpuwhich_t      which;
        id_t            id;
        cpusetid_t      setid;
};
#endif
int
sys_cpuset_setid(struct thread *td, struct cpuset_setid_args *uap)
{

        return (kern_cpuset_setid(td, uap->which, uap->id, uap->setid));
}

int
kern_cpuset_setid(struct thread *td, cpuwhich_t which,
    id_t id, cpusetid_t setid)
{
        struct cpuset *set;
        int error;

        /*
         * Presently we only support per-process sets.
         */
        if (which != CPU_WHICH_PID)
                return (EINVAL);
        set = cpuset_lookup(setid, td);
        if (set == NULL)
                return (ESRCH);
        error = cpuset_setproc(id, set, NULL, NULL, false);
        cpuset_rel(set);
        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct cpuset_getid_args {
        cpulevel_t      level;
        cpuwhich_t      which;
        id_t            id;
        cpusetid_t      *setid;
};
#endif
int
sys_cpuset_getid(struct thread *td, struct cpuset_getid_args *uap)
{

        return (kern_cpuset_getid(td, uap->level, uap->which, uap->id,
            uap->setid));
}

int
kern_cpuset_getid(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id, cpusetid_t *setid)
{
        struct cpuset *nset;
        struct cpuset *set;
        struct thread *ttd;
        struct proc *p;
        cpusetid_t tmpid;
        int error;

        if (level == CPU_LEVEL_WHICH && which != CPU_WHICH_CPUSET)
                return (EINVAL);
        error = cpuset_which(which, id, &p, &ttd, &set);
        if (error)
                return (error);
        switch (which) {
        case CPU_WHICH_TID:
        case CPU_WHICH_PID:
        case CPU_WHICH_TIDPID:
                thread_lock(ttd);
                set = cpuset_refbase(ttd->td_cpuset);
                thread_unlock(ttd);
                PROC_UNLOCK(p);
                break;
        case CPU_WHICH_CPUSET:
        case CPU_WHICH_JAIL:
                break;
        case CPU_WHICH_IRQ:
        case CPU_WHICH_DOMAIN:
                return (EINVAL);
        }
        switch (level) {
        case CPU_LEVEL_ROOT:
                nset = cpuset_refroot(set);
                cpuset_rel(set);
                set = nset;
                break;
        case CPU_LEVEL_CPUSET:
                break;
        case CPU_LEVEL_WHICH:
                break;
        }
        tmpid = set->cs_id;
        cpuset_rel(set);
        if (error == 0)
                error = copyout(&tmpid, setid, sizeof(tmpid));

        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct cpuset_getaffinity_args {
        cpulevel_t      level;
        cpuwhich_t      which;
        id_t            id;
        size_t          cpusetsize;
        cpuset_t        *mask;
};
#endif
int
sys_cpuset_getaffinity(struct thread *td, struct cpuset_getaffinity_args *uap)
{

        return (user_cpuset_getaffinity(td, uap->level, uap->which,
            uap->id, uap->cpusetsize, uap->mask, &copy_set));
}

int
kern_cpuset_getaffinity(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id, size_t cpusetsize, cpuset_t *mask)
{
        struct thread *ttd;
        struct cpuset *nset;
        struct cpuset *set;
        struct proc *p;
        int error;

        error = cpuset_check_capabilities(td, level, which, id);
        if (error != 0)
                return (error);
        error = cpuset_which2(&which, id, &p, &ttd, &set);
        if (error != 0)
                return (error);
        switch (level) {
        case CPU_LEVEL_ROOT:
        case CPU_LEVEL_CPUSET:
                switch (which) {
                case CPU_WHICH_TID:
                case CPU_WHICH_PID:
                        thread_lock(ttd);
                        set = cpuset_ref(ttd->td_cpuset);
                        thread_unlock(ttd);
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                case CPU_WHICH_DOMAIN:
                        return (EINVAL);
                }
                if (level == CPU_LEVEL_ROOT)
                        nset = cpuset_refroot(set);
                else
                        nset = cpuset_refbase(set);
                CPU_COPY(&nset->cs_mask, mask);
                cpuset_rel(nset);
                break;
        case CPU_LEVEL_WHICH:
                switch (which) {
                case CPU_WHICH_TID:
                        thread_lock(ttd);
                        CPU_COPY(&ttd->td_cpuset->cs_mask, mask);
                        thread_unlock(ttd);
                        break;
                case CPU_WHICH_PID:
                        FOREACH_THREAD_IN_PROC(p, ttd) {
                                thread_lock(ttd);
                                CPU_OR(mask, mask, &ttd->td_cpuset->cs_mask);
                                thread_unlock(ttd);
                        }
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        CPU_COPY(&set->cs_mask, mask);
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                        error = intr_getaffinity(id, which, mask);
                        break;
                case CPU_WHICH_DOMAIN:
                        if (id < 0 || id >= MAXMEMDOM)
                                error = ESRCH;
                        else
                                CPU_COPY(&cpuset_domain[id], mask);
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        if (set)
                cpuset_rel(set);
        if (p)
                PROC_UNLOCK(p);
        if (error == 0) {
                if (cpusetsize < howmany(CPU_FLS(mask), NBBY))
                        return (ERANGE);
#ifdef KTRACE
                if (KTRPOINT(td, KTR_STRUCT))
                        ktrcpuset(mask, cpusetsize);
#endif
        }
        return (error);
}

int
user_cpuset_getaffinity(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id, size_t cpusetsize, cpuset_t *maskp, const struct cpuset_copy_cb *cb)
{
        cpuset_t *mask;
        size_t size;
        int error;

        mask = malloc(sizeof(cpuset_t), M_TEMP, M_WAITOK | M_ZERO);
        size = min(cpusetsize, sizeof(cpuset_t));
        error = kern_cpuset_getaffinity(td, level, which, id, size, mask);
        if (error == 0) {
                error = cb->cpuset_copyout(mask, maskp, size);
                if (error != 0)
                        goto out;
                if (cpusetsize > size) {
                        char *end;
                        char *cp;
                        int rv;

                        end = cp = (char *)&maskp->__bits;
                        end += cpusetsize;
                        cp += size;
                        while (cp != end) {
                                rv = subyte(cp, 0);
                                if (rv == -1) {
                                        error = EFAULT;
                                        goto out;
                                }
                                cp++;
                        }
                }
        }
out:
        free(mask, M_TEMP);
        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct cpuset_setaffinity_args {
        cpulevel_t      level;
        cpuwhich_t      which;
        id_t            id;
        size_t          cpusetsize;
        const cpuset_t  *mask;
};
#endif
int
sys_cpuset_setaffinity(struct thread *td, struct cpuset_setaffinity_args *uap)
{

        return (user_cpuset_setaffinity(td, uap->level, uap->which,
            uap->id, uap->cpusetsize, uap->mask, &copy_set));
}

int
kern_cpuset_setaffinity(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id, cpuset_t *mask)
{
        struct cpuset *nset;
        struct cpuset *set;
        struct thread *ttd;
        struct proc *p;
        int error;

#ifdef KTRACE
        if (KTRPOINT(td, KTR_STRUCT))
                ktrcpuset(mask, sizeof(cpuset_t));
#endif
        error = cpuset_check_capabilities(td, level, which, id);
        if (error != 0)
                return (error);
        if (CPU_EMPTY(mask))
                return (EDEADLK);
        switch (level) {
        case CPU_LEVEL_ROOT:
        case CPU_LEVEL_CPUSET:
                error = cpuset_which(which, id, &p, &ttd, &set);
                if (error)
                        break;
                switch (which) {
                case CPU_WHICH_TID:
                case CPU_WHICH_PID:
                case CPU_WHICH_TIDPID:
                        thread_lock(ttd);
                        set = cpuset_ref(ttd->td_cpuset);
                        thread_unlock(ttd);
                        PROC_UNLOCK(p);
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                case CPU_WHICH_DOMAIN:
                        return (EINVAL);
                }
                if (level == CPU_LEVEL_ROOT)
                        nset = cpuset_refroot(set);
                else
                        nset = cpuset_refbase(set);
                error = cpuset_modify(nset, mask);
                cpuset_rel(nset);
                cpuset_rel(set);
                break;
        case CPU_LEVEL_WHICH:
                switch (which) {
                case CPU_WHICH_TID:
                        error = cpuset_setthread(id, mask);
                        break;
                case CPU_WHICH_PID:
                        error = cpuset_setproc(id, NULL, mask, NULL, false);
                        break;
                case CPU_WHICH_TIDPID:
                        if (id > PID_MAX || id == -1)
                                error = cpuset_setthread(id, mask);
                        else
                                error = cpuset_setproc(id, NULL, mask, NULL,
                                    false);
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        error = cpuset_which(which, id, &p, &ttd, &set);
                        if (error == 0) {
                                error = cpuset_modify(set, mask);
                                cpuset_rel(set);
                        }
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                        error = intr_setaffinity(id, which, mask);
                        break;
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        return (error);
}

int
user_cpuset_setaffinity(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id, size_t cpusetsize, const cpuset_t *maskp, const struct cpuset_copy_cb *cb)
{
        cpuset_t *mask;
        int error;
        size_t size;

        size = min(cpusetsize, sizeof(cpuset_t));
        mask = malloc(sizeof(cpuset_t), M_TEMP, M_WAITOK | M_ZERO);
        error = cb->cpuset_copyin(maskp, mask, size);
        if (error)
                goto out;
        /*
         * Verify that no high bits are set.
         */
        if (cpusetsize > sizeof(cpuset_t)) {
                const char *end, *cp;
                int val;
                end = cp = (const char *)&maskp->__bits;
                end += cpusetsize;
                cp += sizeof(cpuset_t);

                while (cp != end) {
                        val = fubyte(cp);
                        if (val == -1) {
                                error = EFAULT;
                                goto out;
                        }
                        if (val != 0) {
                                error = EINVAL;
                                goto out;
                        }
                        cp++;
                }
        }
        error = kern_cpuset_setaffinity(td, level, which, id, mask);

out:
        free(mask, M_TEMP);
        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct cpuset_getdomain_args {
        cpulevel_t      level;
        cpuwhich_t      which;
        id_t            id;
        size_t          domainsetsize;
        domainset_t     *mask;
        int             *policy;
};
#endif
int
sys_cpuset_getdomain(struct thread *td, struct cpuset_getdomain_args *uap)
{

        return (kern_cpuset_getdomain(td, uap->level, uap->which,
            uap->id, uap->domainsetsize, uap->mask, uap->policy, &copy_set));
}

int
kern_cpuset_getdomain(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id, size_t domainsetsize, domainset_t *maskp, int *policyp,
    const struct cpuset_copy_cb *cb)
{
        struct domainset outset;
        struct thread *ttd;
        struct cpuset *nset;
        struct cpuset *set;
        struct domainset *dset;
        struct proc *p;
        domainset_t *mask;
        int error;

        if (domainsetsize < sizeof(domainset_t) ||
            domainsetsize > DOMAINSET_MAXSIZE / NBBY)
                return (ERANGE);
        error = cpuset_check_capabilities(td, level, which, id);
        if (error != 0)
                return (error);
        mask = malloc(domainsetsize, M_TEMP, M_WAITOK | M_ZERO);
        bzero(&outset, sizeof(outset));
        error = cpuset_which2(&which, id, &p, &ttd, &set);
        if (error)
                goto out;
        switch (level) {
        case CPU_LEVEL_ROOT:
        case CPU_LEVEL_CPUSET:
                switch (which) {
                case CPU_WHICH_TID:
                case CPU_WHICH_PID:
                        thread_lock(ttd);
                        set = cpuset_ref(ttd->td_cpuset);
                        thread_unlock(ttd);
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                case CPU_WHICH_DOMAIN:
                        error = EINVAL;
                        goto out;
                }
                if (level == CPU_LEVEL_ROOT)
                        nset = cpuset_refroot(set);
                else
                        nset = cpuset_refbase(set);
                domainset_copy(nset->cs_domain, &outset);
                cpuset_rel(nset);
                break;
        case CPU_LEVEL_WHICH:
                switch (which) {
                case CPU_WHICH_TID:
                        thread_lock(ttd);
                        domainset_copy(ttd->td_cpuset->cs_domain, &outset);
                        thread_unlock(ttd);
                        break;
                case CPU_WHICH_PID:
                        FOREACH_THREAD_IN_PROC(p, ttd) {
                                thread_lock(ttd);
                                dset = ttd->td_cpuset->cs_domain;
                                /* Show all domains in the proc. */
                                DOMAINSET_OR(&outset.ds_mask, &dset->ds_mask);
                                /* Last policy wins. */
                                outset.ds_policy = dset->ds_policy;
                                outset.ds_prefer = dset->ds_prefer;
                                thread_unlock(ttd);
                        }
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        domainset_copy(set->cs_domain, &outset);
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                case CPU_WHICH_DOMAIN:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        if (set)
                cpuset_rel(set);
        if (p)
                PROC_UNLOCK(p);
        /*
         * Translate prefer into a set containing only the preferred domain,
         * not the entire fallback set.
         */
        if (outset.ds_policy == DOMAINSET_POLICY_PREFER) {
                DOMAINSET_ZERO(&outset.ds_mask);
                DOMAINSET_SET(outset.ds_prefer, &outset.ds_mask);
        }
        DOMAINSET_COPY(&outset.ds_mask, mask);
        if (error == 0)
                error = cb->cpuset_copyout(mask, maskp, domainsetsize);
        if (error == 0)
                if (suword32(policyp, outset.ds_policy) != 0)
                        error = EFAULT;
out:
        free(mask, M_TEMP);
        return (error);
}

#ifndef _SYS_SYSPROTO_H_
struct cpuset_setdomain_args {
        cpulevel_t      level;
        cpuwhich_t      which;
        id_t            id;
        size_t          domainsetsize;
        domainset_t     *mask;
        int             policy;
};
#endif
int
sys_cpuset_setdomain(struct thread *td, struct cpuset_setdomain_args *uap)
{

        return (kern_cpuset_setdomain(td, uap->level, uap->which,
            uap->id, uap->domainsetsize, uap->mask, uap->policy, &copy_set));
}

int
kern_cpuset_setdomain(struct thread *td, cpulevel_t level, cpuwhich_t which,
    id_t id, size_t domainsetsize, const domainset_t *maskp, int policy,
    const struct cpuset_copy_cb *cb)
{
        struct cpuset *nset;
        struct cpuset *set;
        struct thread *ttd;
        struct proc *p;
        struct domainset domain;
        domainset_t *mask;
        int error;

        if (domainsetsize < sizeof(domainset_t) ||
            domainsetsize > DOMAINSET_MAXSIZE / NBBY)
                return (ERANGE);
        if (policy <= DOMAINSET_POLICY_INVALID ||
            policy > DOMAINSET_POLICY_MAX)
                return (EINVAL);
        error = cpuset_check_capabilities(td, level, which, id);
        if (error != 0)
                return (error);
        memset(&domain, 0, sizeof(domain));
        mask = malloc(domainsetsize, M_TEMP, M_WAITOK | M_ZERO);
        error = cb->cpuset_copyin(maskp, mask, domainsetsize);
        if (error)
                goto out;
        /*
         * Verify that no high bits are set.
         */
        if (domainsetsize > sizeof(domainset_t)) {
                char *end;
                char *cp;

                end = cp = (char *)&mask->__bits;
                end += domainsetsize;
                cp += sizeof(domainset_t);
                while (cp != end)
                        if (*cp++ != 0) {
                                error = EINVAL;
                                goto out;
                        }
        }
        if (DOMAINSET_EMPTY(mask)) {
                error = EDEADLK;
                goto out;
        }
        DOMAINSET_COPY(mask, &domain.ds_mask);
        domain.ds_policy = policy;

        /*
         * Sanitize the provided mask.
         */
        if (!DOMAINSET_SUBSET(&all_domains, &domain.ds_mask)) {
                error = EINVAL;
                goto out;
        }

        /* Translate preferred policy into a mask and fallback. */
        if (policy == DOMAINSET_POLICY_PREFER) {
                /* Only support a single preferred domain. */
                if (DOMAINSET_COUNT(&domain.ds_mask) != 1) {
                        error = EINVAL;
                        goto out;
                }
                domain.ds_prefer = DOMAINSET_FFS(&domain.ds_mask) - 1;
                /* This will be constrained by domainset_shadow(). */
                DOMAINSET_COPY(&all_domains, &domain.ds_mask);
        }

        /*
         * When given an impossible policy, fall back to interleaving
         * across all domains.
         */
        if (domainset_empty_vm(&domain))
                domainset_copy(domainset2, &domain);

        switch (level) {
        case CPU_LEVEL_ROOT:
        case CPU_LEVEL_CPUSET:
                error = cpuset_which(which, id, &p, &ttd, &set);
                if (error)
                        break;
                switch (which) {
                case CPU_WHICH_TID:
                case CPU_WHICH_PID:
                case CPU_WHICH_TIDPID:
                        thread_lock(ttd);
                        set = cpuset_ref(ttd->td_cpuset);
                        thread_unlock(ttd);
                        PROC_UNLOCK(p);
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                case CPU_WHICH_DOMAIN:
                        error = EINVAL;
                        goto out;
                }
                if (level == CPU_LEVEL_ROOT)
                        nset = cpuset_refroot(set);
                else
                        nset = cpuset_refbase(set);
                error = cpuset_modify_domain(nset, &domain);
                cpuset_rel(nset);
                cpuset_rel(set);
                break;
        case CPU_LEVEL_WHICH:
                switch (which) {
                case CPU_WHICH_TID:
                        error = _cpuset_setthread(id, NULL, &domain);
                        break;
                case CPU_WHICH_PID:
                        error = cpuset_setproc(id, NULL, NULL, &domain, false);
                        break;
                case CPU_WHICH_TIDPID:
                        if (id > PID_MAX || id == -1)
                                error = _cpuset_setthread(id, NULL, &domain);
                        else
                                error = cpuset_setproc(id, NULL, NULL, &domain,
                                    false);
                        break;
                case CPU_WHICH_CPUSET:
                case CPU_WHICH_JAIL:
                        error = cpuset_which(which, id, &p, &ttd, &set);
                        if (error == 0) {
                                error = cpuset_modify_domain(set, &domain);
                                cpuset_rel(set);
                        }
                        break;
                case CPU_WHICH_IRQ:
                case CPU_WHICH_INTRHANDLER:
                case CPU_WHICH_ITHREAD:
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
out:
        free(mask, M_TEMP);
        return (error);
}

#ifdef DDB

static void
ddb_display_bitset(const struct bitset *set, int size)
{
        int bit, once;

        for (once = 0, bit = 0; bit < size; bit++) {
                if (CPU_ISSET(bit, set)) {
                        if (once == 0) {
                                db_printf("%d", bit);
                                once = 1;
                        } else  
                                db_printf(",%d", bit);
                }
        }
        if (once == 0)
                db_printf("<none>");
}

void
ddb_display_cpuset(const cpuset_t *set)
{
        ddb_display_bitset((const struct bitset *)set, CPU_SETSIZE);
}

static void
ddb_display_domainset(const domainset_t *set)
{
        ddb_display_bitset((const struct bitset *)set, DOMAINSET_SETSIZE);
}

DB_SHOW_COMMAND(cpusets, db_show_cpusets)
{
        struct cpuset *set;

        LIST_FOREACH(set, &cpuset_ids, cs_link) {
                db_printf("set=%p id=%-6u ref=%-6d flags=0x%04x parent id=%d\n",
                    set, set->cs_id, refcount_load(&set->cs_ref), set->cs_flags,
                    (set->cs_parent != NULL) ? set->cs_parent->cs_id : 0);
                db_printf("  cpu mask=");
                ddb_display_cpuset(&set->cs_mask);
                db_printf("\n");
                db_printf("  domain policy %d prefer %d mask=",
                    set->cs_domain->ds_policy, set->cs_domain->ds_prefer);
                ddb_display_domainset(&set->cs_domain->ds_mask);
                db_printf("\n");
                if (db_pager_quit)
                        break;
        }
}

DB_SHOW_COMMAND(domainsets, db_show_domainsets)
{
        struct domainset *set;

        LIST_FOREACH(set, &cpuset_domains, ds_link) {
                db_printf("set=%p policy %d prefer %d cnt %d\n",
                    set, set->ds_policy, set->ds_prefer, set->ds_cnt);
                db_printf("  mask =");
                ddb_display_domainset(&set->ds_mask);
                db_printf("\n");
        }
}
#endif /* DDB */