1268 lines
32 KiB
C
1268 lines
32 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (C) 2001 Julian Elischer <julian@freebsd.org>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice(s), this list of conditions and the following disclaimer as
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* the first lines of this file unmodified other than the possible
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* addition of one or more copyright notices.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice(s), this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*/
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#include "opt_witness.h"
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#include "opt_hwpmc_hooks.h"
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/epoch.h>
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#include <sys/rangelock.h>
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#include <sys/resourcevar.h>
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#include <sys/sdt.h>
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#include <sys/smp.h>
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#include <sys/sched.h>
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#include <sys/sleepqueue.h>
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#include <sys/selinfo.h>
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#include <sys/syscallsubr.h>
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#include <sys/sysent.h>
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#include <sys/turnstile.h>
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#include <sys/ktr.h>
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#include <sys/rwlock.h>
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#include <sys/umtx.h>
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#include <sys/vmmeter.h>
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#include <sys/cpuset.h>
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#ifdef HWPMC_HOOKS
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#include <sys/pmckern.h>
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#endif
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#include <security/audit/audit.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <vm/uma.h>
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#include <sys/eventhandler.h>
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/*
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* Asserts below verify the stability of struct thread and struct proc
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* layout, as exposed by KBI to modules. On head, the KBI is allowed
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* to drift, change to the structures must be accompanied by the
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* assert update.
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*
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* On the stable branches after KBI freeze, conditions must not be
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* violated. Typically new fields are moved to the end of the
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* structures.
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*/
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#ifdef __amd64__
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_Static_assert(offsetof(struct thread, td_flags) == 0xfc,
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"struct thread KBI td_flags");
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_Static_assert(offsetof(struct thread, td_pflags) == 0x104,
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"struct thread KBI td_pflags");
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_Static_assert(offsetof(struct thread, td_frame) == 0x470,
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"struct thread KBI td_frame");
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_Static_assert(offsetof(struct thread, td_emuldata) == 0x528,
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"struct thread KBI td_emuldata");
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_Static_assert(offsetof(struct proc, p_flag) == 0xb0,
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"struct proc KBI p_flag");
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_Static_assert(offsetof(struct proc, p_pid) == 0xbc,
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"struct proc KBI p_pid");
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_Static_assert(offsetof(struct proc, p_filemon) == 0x3d0,
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"struct proc KBI p_filemon");
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_Static_assert(offsetof(struct proc, p_comm) == 0x3e4,
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"struct proc KBI p_comm");
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_Static_assert(offsetof(struct proc, p_emuldata) == 0x4b8,
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"struct proc KBI p_emuldata");
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#endif
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#ifdef __i386__
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_Static_assert(offsetof(struct thread, td_flags) == 0x98,
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"struct thread KBI td_flags");
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_Static_assert(offsetof(struct thread, td_pflags) == 0xa0,
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"struct thread KBI td_pflags");
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_Static_assert(offsetof(struct thread, td_frame) == 0x2e8,
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"struct thread KBI td_frame");
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_Static_assert(offsetof(struct thread, td_emuldata) == 0x334,
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"struct thread KBI td_emuldata");
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_Static_assert(offsetof(struct proc, p_flag) == 0x68,
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"struct proc KBI p_flag");
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_Static_assert(offsetof(struct proc, p_pid) == 0x74,
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"struct proc KBI p_pid");
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_Static_assert(offsetof(struct proc, p_filemon) == 0x27c,
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"struct proc KBI p_filemon");
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_Static_assert(offsetof(struct proc, p_comm) == 0x28c,
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"struct proc KBI p_comm");
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_Static_assert(offsetof(struct proc, p_emuldata) == 0x318,
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"struct proc KBI p_emuldata");
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#endif
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SDT_PROVIDER_DECLARE(proc);
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SDT_PROBE_DEFINE(proc, , , lwp__exit);
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/*
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* thread related storage.
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*/
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static uma_zone_t thread_zone;
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TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
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static struct mtx zombie_lock;
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MTX_SYSINIT(zombie_lock, &zombie_lock, "zombie lock", MTX_SPIN);
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static void thread_zombie(struct thread *);
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static int thread_unsuspend_one(struct thread *td, struct proc *p,
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bool boundary);
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#define TID_BUFFER_SIZE 1024
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struct mtx tid_lock;
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static struct unrhdr *tid_unrhdr;
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static lwpid_t tid_buffer[TID_BUFFER_SIZE];
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static int tid_head, tid_tail;
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static MALLOC_DEFINE(M_TIDHASH, "tidhash", "thread hash");
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struct tidhashhead *tidhashtbl;
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u_long tidhash;
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struct rwlock tidhash_lock;
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EVENTHANDLER_LIST_DEFINE(thread_ctor);
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EVENTHANDLER_LIST_DEFINE(thread_dtor);
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EVENTHANDLER_LIST_DEFINE(thread_init);
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EVENTHANDLER_LIST_DEFINE(thread_fini);
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static lwpid_t
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tid_alloc(void)
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{
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lwpid_t tid;
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tid = alloc_unr(tid_unrhdr);
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if (tid != -1)
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return (tid);
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mtx_lock(&tid_lock);
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if (tid_head == tid_tail) {
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mtx_unlock(&tid_lock);
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return (-1);
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}
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tid = tid_buffer[tid_head];
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tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
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mtx_unlock(&tid_lock);
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return (tid);
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}
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static void
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tid_free(lwpid_t tid)
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{
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lwpid_t tmp_tid = -1;
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mtx_lock(&tid_lock);
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if ((tid_tail + 1) % TID_BUFFER_SIZE == tid_head) {
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tmp_tid = tid_buffer[tid_head];
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tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
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}
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tid_buffer[tid_tail] = tid;
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tid_tail = (tid_tail + 1) % TID_BUFFER_SIZE;
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mtx_unlock(&tid_lock);
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if (tmp_tid != -1)
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free_unr(tid_unrhdr, tmp_tid);
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}
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/*
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* Prepare a thread for use.
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*/
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static int
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thread_ctor(void *mem, int size, void *arg, int flags)
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{
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struct thread *td;
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td = (struct thread *)mem;
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td->td_state = TDS_INACTIVE;
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td->td_oncpu = NOCPU;
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td->td_tid = tid_alloc();
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/*
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* Note that td_critnest begins life as 1 because the thread is not
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* running and is thereby implicitly waiting to be on the receiving
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* end of a context switch.
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*/
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td->td_critnest = 1;
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td->td_lend_user_pri = PRI_MAX;
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EVENTHANDLER_DIRECT_INVOKE(thread_ctor, td);
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#ifdef AUDIT
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audit_thread_alloc(td);
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#endif
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umtx_thread_alloc(td);
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return (0);
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}
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/*
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* Reclaim a thread after use.
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*/
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static void
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thread_dtor(void *mem, int size, void *arg)
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{
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struct thread *td;
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td = (struct thread *)mem;
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#ifdef INVARIANTS
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/* Verify that this thread is in a safe state to free. */
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switch (td->td_state) {
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case TDS_INHIBITED:
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case TDS_RUNNING:
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case TDS_CAN_RUN:
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case TDS_RUNQ:
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/*
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* We must never unlink a thread that is in one of
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* these states, because it is currently active.
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*/
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panic("bad state for thread unlinking");
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/* NOTREACHED */
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case TDS_INACTIVE:
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break;
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default:
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panic("bad thread state");
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/* NOTREACHED */
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}
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#endif
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#ifdef AUDIT
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audit_thread_free(td);
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#endif
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/* Free all OSD associated to this thread. */
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osd_thread_exit(td);
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td_softdep_cleanup(td);
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MPASS(td->td_su == NULL);
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EVENTHANDLER_DIRECT_INVOKE(thread_dtor, td);
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tid_free(td->td_tid);
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}
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/*
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* Initialize type-stable parts of a thread (when newly created).
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*/
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static int
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thread_init(void *mem, int size, int flags)
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{
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struct thread *td;
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td = (struct thread *)mem;
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td->td_sleepqueue = sleepq_alloc();
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td->td_turnstile = turnstile_alloc();
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td->td_rlqe = NULL;
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EVENTHANDLER_DIRECT_INVOKE(thread_init, td);
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umtx_thread_init(td);
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epoch_thread_init(td);
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td->td_kstack = 0;
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td->td_sel = NULL;
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return (0);
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}
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/*
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* Tear down type-stable parts of a thread (just before being discarded).
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*/
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static void
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thread_fini(void *mem, int size)
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{
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struct thread *td;
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td = (struct thread *)mem;
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EVENTHANDLER_DIRECT_INVOKE(thread_fini, td);
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rlqentry_free(td->td_rlqe);
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turnstile_free(td->td_turnstile);
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sleepq_free(td->td_sleepqueue);
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umtx_thread_fini(td);
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epoch_thread_fini(td);
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seltdfini(td);
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}
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/*
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* For a newly created process,
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* link up all the structures and its initial threads etc.
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* called from:
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* {arch}/{arch}/machdep.c {arch}_init(), init386() etc.
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* proc_dtor() (should go away)
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* proc_init()
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*/
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void
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proc_linkup0(struct proc *p, struct thread *td)
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{
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TAILQ_INIT(&p->p_threads); /* all threads in proc */
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proc_linkup(p, td);
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}
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void
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proc_linkup(struct proc *p, struct thread *td)
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{
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sigqueue_init(&p->p_sigqueue, p);
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p->p_ksi = ksiginfo_alloc(1);
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if (p->p_ksi != NULL) {
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/* XXX p_ksi may be null if ksiginfo zone is not ready */
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p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
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}
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LIST_INIT(&p->p_mqnotifier);
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p->p_numthreads = 0;
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thread_link(td, p);
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}
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/*
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* Initialize global thread allocation resources.
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*/
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void
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threadinit(void)
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{
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mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
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/*
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* pid_max cannot be greater than PID_MAX.
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* leave one number for thread0.
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*/
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tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock);
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thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
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thread_ctor, thread_dtor, thread_init, thread_fini,
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32 - 1, UMA_ZONE_NOFREE);
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tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash);
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rw_init(&tidhash_lock, "tidhash");
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}
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/*
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* Place an unused thread on the zombie list.
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* Use the slpq as that must be unused by now.
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*/
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void
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thread_zombie(struct thread *td)
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{
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mtx_lock_spin(&zombie_lock);
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TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
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mtx_unlock_spin(&zombie_lock);
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}
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/*
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* Release a thread that has exited after cpu_throw().
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*/
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void
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thread_stash(struct thread *td)
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{
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atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1);
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thread_zombie(td);
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}
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/*
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* Reap zombie resources.
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*/
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void
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thread_reap(void)
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{
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struct thread *td_first, *td_next;
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/*
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* Don't even bother to lock if none at this instant,
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* we really don't care about the next instant.
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*/
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if (!TAILQ_EMPTY(&zombie_threads)) {
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mtx_lock_spin(&zombie_lock);
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td_first = TAILQ_FIRST(&zombie_threads);
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if (td_first)
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TAILQ_INIT(&zombie_threads);
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mtx_unlock_spin(&zombie_lock);
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while (td_first) {
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td_next = TAILQ_NEXT(td_first, td_slpq);
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thread_cow_free(td_first);
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thread_free(td_first);
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td_first = td_next;
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}
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}
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}
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/*
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* Allocate a thread.
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*/
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struct thread *
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thread_alloc(int pages)
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{
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struct thread *td;
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thread_reap(); /* check if any zombies to get */
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td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
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KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
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if (!vm_thread_new(td, pages)) {
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uma_zfree(thread_zone, td);
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return (NULL);
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}
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cpu_thread_alloc(td);
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return (td);
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}
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int
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thread_alloc_stack(struct thread *td, int pages)
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{
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KASSERT(td->td_kstack == 0,
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("thread_alloc_stack called on a thread with kstack"));
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if (!vm_thread_new(td, pages))
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return (0);
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cpu_thread_alloc(td);
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return (1);
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}
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/*
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* Deallocate a thread.
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*/
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void
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thread_free(struct thread *td)
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{
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lock_profile_thread_exit(td);
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if (td->td_cpuset)
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cpuset_rel(td->td_cpuset);
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td->td_cpuset = NULL;
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cpu_thread_free(td);
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if (td->td_kstack != 0)
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vm_thread_dispose(td);
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callout_drain(&td->td_slpcallout);
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uma_zfree(thread_zone, td);
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}
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void
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thread_cow_get_proc(struct thread *newtd, struct proc *p)
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{
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PROC_LOCK_ASSERT(p, MA_OWNED);
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newtd->td_ucred = crhold(p->p_ucred);
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newtd->td_limit = lim_hold(p->p_limit);
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newtd->td_cowgen = p->p_cowgen;
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}
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void
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thread_cow_get(struct thread *newtd, struct thread *td)
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{
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newtd->td_ucred = crhold(td->td_ucred);
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newtd->td_limit = lim_hold(td->td_limit);
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newtd->td_cowgen = td->td_cowgen;
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}
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void
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thread_cow_free(struct thread *td)
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{
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if (td->td_ucred != NULL)
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crfree(td->td_ucred);
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if (td->td_limit != NULL)
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lim_free(td->td_limit);
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}
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void
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thread_cow_update(struct thread *td)
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{
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struct proc *p;
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struct ucred *oldcred;
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struct plimit *oldlimit;
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p = td->td_proc;
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oldcred = NULL;
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oldlimit = NULL;
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PROC_LOCK(p);
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if (td->td_ucred != p->p_ucred) {
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oldcred = td->td_ucred;
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td->td_ucred = crhold(p->p_ucred);
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}
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if (td->td_limit != p->p_limit) {
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oldlimit = td->td_limit;
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td->td_limit = lim_hold(p->p_limit);
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}
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td->td_cowgen = p->p_cowgen;
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PROC_UNLOCK(p);
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if (oldcred != NULL)
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crfree(oldcred);
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if (oldlimit != NULL)
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lim_free(oldlimit);
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}
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|
|
/*
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|
* Discard the current thread and exit from its context.
|
|
* Always called with scheduler locked.
|
|
*
|
|
* Because we can't free a thread while we're operating under its context,
|
|
* push the current thread into our CPU's deadthread holder. This means
|
|
* we needn't worry about someone else grabbing our context before we
|
|
* do a cpu_throw().
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|
*/
|
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void
|
|
thread_exit(void)
|
|
{
|
|
uint64_t runtime, new_switchtime;
|
|
struct thread *td;
|
|
struct thread *td2;
|
|
struct proc *p;
|
|
int wakeup_swapper;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
KASSERT(p != NULL, ("thread exiting without a process"));
|
|
CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
|
|
(long)p->p_pid, td->td_name);
|
|
SDT_PROBE0(proc, , , lwp__exit);
|
|
KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
|
|
|
|
/*
|
|
* drop FPU & debug register state storage, or any other
|
|
* architecture specific resources that
|
|
* would not be on a new untouched process.
|
|
*/
|
|
cpu_thread_exit(td);
|
|
|
|
/*
|
|
* The last thread is left attached to the process
|
|
* So that the whole bundle gets recycled. Skip
|
|
* all this stuff if we never had threads.
|
|
* EXIT clears all sign of other threads when
|
|
* it goes to single threading, so the last thread always
|
|
* takes the short path.
|
|
*/
|
|
if (p->p_flag & P_HADTHREADS) {
|
|
if (p->p_numthreads > 1) {
|
|
atomic_add_int(&td->td_proc->p_exitthreads, 1);
|
|
thread_unlink(td);
|
|
td2 = FIRST_THREAD_IN_PROC(p);
|
|
sched_exit_thread(td2, td);
|
|
|
|
/*
|
|
* The test below is NOT true if we are the
|
|
* sole exiting thread. P_STOPPED_SINGLE is unset
|
|
* in exit1() after it is the only survivor.
|
|
*/
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
if (p->p_numthreads == p->p_suspcount) {
|
|
thread_lock(p->p_singlethread);
|
|
wakeup_swapper = thread_unsuspend_one(
|
|
p->p_singlethread, p, false);
|
|
thread_unlock(p->p_singlethread);
|
|
if (wakeup_swapper)
|
|
kick_proc0();
|
|
}
|
|
}
|
|
|
|
PCPU_SET(deadthread, td);
|
|
} else {
|
|
/*
|
|
* The last thread is exiting.. but not through exit()
|
|
*/
|
|
panic ("thread_exit: Last thread exiting on its own");
|
|
}
|
|
}
|
|
#ifdef HWPMC_HOOKS
|
|
/*
|
|
* If this thread is part of a process that is being tracked by hwpmc(4),
|
|
* inform the module of the thread's impending exit.
|
|
*/
|
|
if (PMC_PROC_IS_USING_PMCS(td->td_proc)) {
|
|
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
|
|
PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT, NULL);
|
|
} else if (PMC_SYSTEM_SAMPLING_ACTIVE())
|
|
PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT_LOG, NULL);
|
|
#endif
|
|
PROC_UNLOCK(p);
|
|
PROC_STATLOCK(p);
|
|
thread_lock(td);
|
|
PROC_SUNLOCK(p);
|
|
|
|
/* Do the same timestamp bookkeeping that mi_switch() would do. */
|
|
new_switchtime = cpu_ticks();
|
|
runtime = new_switchtime - PCPU_GET(switchtime);
|
|
td->td_runtime += runtime;
|
|
td->td_incruntime += runtime;
|
|
PCPU_SET(switchtime, new_switchtime);
|
|
PCPU_SET(switchticks, ticks);
|
|
VM_CNT_INC(v_swtch);
|
|
|
|
/* Save our resource usage in our process. */
|
|
td->td_ru.ru_nvcsw++;
|
|
ruxagg(p, td);
|
|
rucollect(&p->p_ru, &td->td_ru);
|
|
PROC_STATUNLOCK(p);
|
|
|
|
td->td_state = TDS_INACTIVE;
|
|
#ifdef WITNESS
|
|
witness_thread_exit(td);
|
|
#endif
|
|
CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
|
|
sched_throw(td);
|
|
panic("I'm a teapot!");
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
/*
|
|
* Do any thread specific cleanups that may be needed in wait()
|
|
* called with Giant, proc and schedlock not held.
|
|
*/
|
|
void
|
|
thread_wait(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
KASSERT(p->p_numthreads == 1, ("multiple threads in thread_wait()"));
|
|
KASSERT(p->p_exitthreads == 0, ("p_exitthreads leaking"));
|
|
td = FIRST_THREAD_IN_PROC(p);
|
|
/* Lock the last thread so we spin until it exits cpu_throw(). */
|
|
thread_lock(td);
|
|
thread_unlock(td);
|
|
lock_profile_thread_exit(td);
|
|
cpuset_rel(td->td_cpuset);
|
|
td->td_cpuset = NULL;
|
|
cpu_thread_clean(td);
|
|
thread_cow_free(td);
|
|
callout_drain(&td->td_slpcallout);
|
|
thread_reap(); /* check for zombie threads etc. */
|
|
}
|
|
|
|
/*
|
|
* Link a thread to a process.
|
|
* set up anything that needs to be initialized for it to
|
|
* be used by the process.
|
|
*/
|
|
void
|
|
thread_link(struct thread *td, struct proc *p)
|
|
{
|
|
|
|
/*
|
|
* XXX This can't be enabled because it's called for proc0 before
|
|
* its lock has been created.
|
|
* PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
*/
|
|
td->td_state = TDS_INACTIVE;
|
|
td->td_proc = p;
|
|
td->td_flags = TDF_INMEM;
|
|
|
|
LIST_INIT(&td->td_contested);
|
|
LIST_INIT(&td->td_lprof[0]);
|
|
LIST_INIT(&td->td_lprof[1]);
|
|
sigqueue_init(&td->td_sigqueue, p);
|
|
callout_init(&td->td_slpcallout, 1);
|
|
TAILQ_INSERT_TAIL(&p->p_threads, td, td_plist);
|
|
p->p_numthreads++;
|
|
}
|
|
|
|
/*
|
|
* Called from:
|
|
* thread_exit()
|
|
*/
|
|
void
|
|
thread_unlink(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
TAILQ_REMOVE(&p->p_threads, td, td_plist);
|
|
p->p_numthreads--;
|
|
/* could clear a few other things here */
|
|
/* Must NOT clear links to proc! */
|
|
}
|
|
|
|
static int
|
|
calc_remaining(struct proc *p, int mode)
|
|
{
|
|
int remaining;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
if (mode == SINGLE_EXIT)
|
|
remaining = p->p_numthreads;
|
|
else if (mode == SINGLE_BOUNDARY)
|
|
remaining = p->p_numthreads - p->p_boundary_count;
|
|
else if (mode == SINGLE_NO_EXIT || mode == SINGLE_ALLPROC)
|
|
remaining = p->p_numthreads - p->p_suspcount;
|
|
else
|
|
panic("calc_remaining: wrong mode %d", mode);
|
|
return (remaining);
|
|
}
|
|
|
|
static int
|
|
remain_for_mode(int mode)
|
|
{
|
|
|
|
return (mode == SINGLE_ALLPROC ? 0 : 1);
|
|
}
|
|
|
|
static int
|
|
weed_inhib(int mode, struct thread *td2, struct proc *p)
|
|
{
|
|
int wakeup_swapper;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
THREAD_LOCK_ASSERT(td2, MA_OWNED);
|
|
|
|
wakeup_swapper = 0;
|
|
switch (mode) {
|
|
case SINGLE_EXIT:
|
|
if (TD_IS_SUSPENDED(td2))
|
|
wakeup_swapper |= thread_unsuspend_one(td2, p, true);
|
|
if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
|
|
wakeup_swapper |= sleepq_abort(td2, EINTR);
|
|
break;
|
|
case SINGLE_BOUNDARY:
|
|
case SINGLE_NO_EXIT:
|
|
if (TD_IS_SUSPENDED(td2) && (td2->td_flags & TDF_BOUNDARY) == 0)
|
|
wakeup_swapper |= thread_unsuspend_one(td2, p, false);
|
|
if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
|
|
wakeup_swapper |= sleepq_abort(td2, ERESTART);
|
|
break;
|
|
case SINGLE_ALLPROC:
|
|
/*
|
|
* ALLPROC suspend tries to avoid spurious EINTR for
|
|
* threads sleeping interruptable, by suspending the
|
|
* thread directly, similarly to sig_suspend_threads().
|
|
* Since such sleep is not performed at the user
|
|
* boundary, TDF_BOUNDARY flag is not set, and TDF_ALLPROCSUSP
|
|
* is used to avoid immediate un-suspend.
|
|
*/
|
|
if (TD_IS_SUSPENDED(td2) && (td2->td_flags & (TDF_BOUNDARY |
|
|
TDF_ALLPROCSUSP)) == 0)
|
|
wakeup_swapper |= thread_unsuspend_one(td2, p, false);
|
|
if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0) {
|
|
if ((td2->td_flags & TDF_SBDRY) == 0) {
|
|
thread_suspend_one(td2);
|
|
td2->td_flags |= TDF_ALLPROCSUSP;
|
|
} else {
|
|
wakeup_swapper |= sleepq_abort(td2, ERESTART);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
return (wakeup_swapper);
|
|
}
|
|
|
|
/*
|
|
* Enforce single-threading.
|
|
*
|
|
* Returns 1 if the caller must abort (another thread is waiting to
|
|
* exit the process or similar). Process is locked!
|
|
* Returns 0 when you are successfully the only thread running.
|
|
* A process has successfully single threaded in the suspend mode when
|
|
* There are no threads in user mode. Threads in the kernel must be
|
|
* allowed to continue until they get to the user boundary. They may even
|
|
* copy out their return values and data before suspending. They may however be
|
|
* accelerated in reaching the user boundary as we will wake up
|
|
* any sleeping threads that are interruptable. (PCATCH).
|
|
*/
|
|
int
|
|
thread_single(struct proc *p, int mode)
|
|
{
|
|
struct thread *td;
|
|
struct thread *td2;
|
|
int remaining, wakeup_swapper;
|
|
|
|
td = curthread;
|
|
KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY ||
|
|
mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT,
|
|
("invalid mode %d", mode));
|
|
/*
|
|
* If allowing non-ALLPROC singlethreading for non-curproc
|
|
* callers, calc_remaining() and remain_for_mode() should be
|
|
* adjusted to also account for td->td_proc != p. For now
|
|
* this is not implemented because it is not used.
|
|
*/
|
|
KASSERT((mode == SINGLE_ALLPROC && td->td_proc != p) ||
|
|
(mode != SINGLE_ALLPROC && td->td_proc == p),
|
|
("mode %d proc %p curproc %p", mode, p, td->td_proc));
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
|
|
if ((p->p_flag & P_HADTHREADS) == 0 && mode != SINGLE_ALLPROC)
|
|
return (0);
|
|
|
|
/* Is someone already single threading? */
|
|
if (p->p_singlethread != NULL && p->p_singlethread != td)
|
|
return (1);
|
|
|
|
if (mode == SINGLE_EXIT) {
|
|
p->p_flag |= P_SINGLE_EXIT;
|
|
p->p_flag &= ~P_SINGLE_BOUNDARY;
|
|
} else {
|
|
p->p_flag &= ~P_SINGLE_EXIT;
|
|
if (mode == SINGLE_BOUNDARY)
|
|
p->p_flag |= P_SINGLE_BOUNDARY;
|
|
else
|
|
p->p_flag &= ~P_SINGLE_BOUNDARY;
|
|
}
|
|
if (mode == SINGLE_ALLPROC)
|
|
p->p_flag |= P_TOTAL_STOP;
|
|
p->p_flag |= P_STOPPED_SINGLE;
|
|
PROC_SLOCK(p);
|
|
p->p_singlethread = td;
|
|
remaining = calc_remaining(p, mode);
|
|
while (remaining != remain_for_mode(mode)) {
|
|
if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
|
|
goto stopme;
|
|
wakeup_swapper = 0;
|
|
FOREACH_THREAD_IN_PROC(p, td2) {
|
|
if (td2 == td)
|
|
continue;
|
|
thread_lock(td2);
|
|
td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
|
|
if (TD_IS_INHIBITED(td2)) {
|
|
wakeup_swapper |= weed_inhib(mode, td2, p);
|
|
#ifdef SMP
|
|
} else if (TD_IS_RUNNING(td2) && td != td2) {
|
|
forward_signal(td2);
|
|
#endif
|
|
}
|
|
thread_unlock(td2);
|
|
}
|
|
if (wakeup_swapper)
|
|
kick_proc0();
|
|
remaining = calc_remaining(p, mode);
|
|
|
|
/*
|
|
* Maybe we suspended some threads.. was it enough?
|
|
*/
|
|
if (remaining == remain_for_mode(mode))
|
|
break;
|
|
|
|
stopme:
|
|
/*
|
|
* Wake us up when everyone else has suspended.
|
|
* In the mean time we suspend as well.
|
|
*/
|
|
thread_suspend_switch(td, p);
|
|
remaining = calc_remaining(p, mode);
|
|
}
|
|
if (mode == SINGLE_EXIT) {
|
|
/*
|
|
* Convert the process to an unthreaded process. The
|
|
* SINGLE_EXIT is called by exit1() or execve(), in
|
|
* both cases other threads must be retired.
|
|
*/
|
|
KASSERT(p->p_numthreads == 1, ("Unthreading with >1 threads"));
|
|
p->p_singlethread = NULL;
|
|
p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_HADTHREADS);
|
|
|
|
/*
|
|
* Wait for any remaining threads to exit cpu_throw().
|
|
*/
|
|
while (p->p_exitthreads != 0) {
|
|
PROC_SUNLOCK(p);
|
|
PROC_UNLOCK(p);
|
|
sched_relinquish(td);
|
|
PROC_LOCK(p);
|
|
PROC_SLOCK(p);
|
|
}
|
|
} else if (mode == SINGLE_BOUNDARY) {
|
|
/*
|
|
* Wait until all suspended threads are removed from
|
|
* the processors. The thread_suspend_check()
|
|
* increments p_boundary_count while it is still
|
|
* running, which makes it possible for the execve()
|
|
* to destroy vmspace while our other threads are
|
|
* still using the address space.
|
|
*
|
|
* We lock the thread, which is only allowed to
|
|
* succeed after context switch code finished using
|
|
* the address space.
|
|
*/
|
|
FOREACH_THREAD_IN_PROC(p, td2) {
|
|
if (td2 == td)
|
|
continue;
|
|
thread_lock(td2);
|
|
KASSERT((td2->td_flags & TDF_BOUNDARY) != 0,
|
|
("td %p not on boundary", td2));
|
|
KASSERT(TD_IS_SUSPENDED(td2),
|
|
("td %p is not suspended", td2));
|
|
thread_unlock(td2);
|
|
}
|
|
}
|
|
PROC_SUNLOCK(p);
|
|
return (0);
|
|
}
|
|
|
|
bool
|
|
thread_suspend_check_needed(void)
|
|
{
|
|
struct proc *p;
|
|
struct thread *td;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
return (P_SHOULDSTOP(p) || ((p->p_flag & P_TRACED) != 0 &&
|
|
(td->td_dbgflags & TDB_SUSPEND) != 0));
|
|
}
|
|
|
|
/*
|
|
* Called in from locations that can safely check to see
|
|
* whether we have to suspend or at least throttle for a
|
|
* single-thread event (e.g. fork).
|
|
*
|
|
* Such locations include userret().
|
|
* If the "return_instead" argument is non zero, the thread must be able to
|
|
* accept 0 (caller may continue), or 1 (caller must abort) as a result.
|
|
*
|
|
* The 'return_instead' argument tells the function if it may do a
|
|
* thread_exit() or suspend, or whether the caller must abort and back
|
|
* out instead.
|
|
*
|
|
* If the thread that set the single_threading request has set the
|
|
* P_SINGLE_EXIT bit in the process flags then this call will never return
|
|
* if 'return_instead' is false, but will exit.
|
|
*
|
|
* P_SINGLE_EXIT | return_instead == 0| return_instead != 0
|
|
*---------------+--------------------+---------------------
|
|
* 0 | returns 0 | returns 0 or 1
|
|
* | when ST ends | immediately
|
|
*---------------+--------------------+---------------------
|
|
* 1 | thread exits | returns 1
|
|
* | | immediately
|
|
* 0 = thread_exit() or suspension ok,
|
|
* other = return error instead of stopping the thread.
|
|
*
|
|
* While a full suspension is under effect, even a single threading
|
|
* thread would be suspended if it made this call (but it shouldn't).
|
|
* This call should only be made from places where
|
|
* thread_exit() would be safe as that may be the outcome unless
|
|
* return_instead is set.
|
|
*/
|
|
int
|
|
thread_suspend_check(int return_instead)
|
|
{
|
|
struct thread *td;
|
|
struct proc *p;
|
|
int wakeup_swapper;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
while (thread_suspend_check_needed()) {
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
KASSERT(p->p_singlethread != NULL,
|
|
("singlethread not set"));
|
|
/*
|
|
* The only suspension in action is a
|
|
* single-threading. Single threader need not stop.
|
|
* It is safe to access p->p_singlethread unlocked
|
|
* because it can only be set to our address by us.
|
|
*/
|
|
if (p->p_singlethread == td)
|
|
return (0); /* Exempt from stopping. */
|
|
}
|
|
if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
|
|
return (EINTR);
|
|
|
|
/* Should we goto user boundary if we didn't come from there? */
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
|
|
(p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
|
|
return (ERESTART);
|
|
|
|
/*
|
|
* Ignore suspend requests if they are deferred.
|
|
*/
|
|
if ((td->td_flags & TDF_SBDRY) != 0) {
|
|
KASSERT(return_instead,
|
|
("TDF_SBDRY set for unsafe thread_suspend_check"));
|
|
KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) !=
|
|
(TDF_SEINTR | TDF_SERESTART),
|
|
("both TDF_SEINTR and TDF_SERESTART"));
|
|
return (TD_SBDRY_INTR(td) ? TD_SBDRY_ERRNO(td) : 0);
|
|
}
|
|
|
|
/*
|
|
* If the process is waiting for us to exit,
|
|
* this thread should just suicide.
|
|
* Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
|
|
*/
|
|
if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
|
|
PROC_UNLOCK(p);
|
|
|
|
/*
|
|
* Allow Linux emulation layer to do some work
|
|
* before thread suicide.
|
|
*/
|
|
if (__predict_false(p->p_sysent->sv_thread_detach != NULL))
|
|
(p->p_sysent->sv_thread_detach)(td);
|
|
umtx_thread_exit(td);
|
|
kern_thr_exit(td);
|
|
panic("stopped thread did not exit");
|
|
}
|
|
|
|
PROC_SLOCK(p);
|
|
thread_stopped(p);
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
if (p->p_numthreads == p->p_suspcount + 1) {
|
|
thread_lock(p->p_singlethread);
|
|
wakeup_swapper = thread_unsuspend_one(
|
|
p->p_singlethread, p, false);
|
|
thread_unlock(p->p_singlethread);
|
|
if (wakeup_swapper)
|
|
kick_proc0();
|
|
}
|
|
}
|
|
PROC_UNLOCK(p);
|
|
thread_lock(td);
|
|
/*
|
|
* When a thread suspends, it just
|
|
* gets taken off all queues.
|
|
*/
|
|
thread_suspend_one(td);
|
|
if (return_instead == 0) {
|
|
p->p_boundary_count++;
|
|
td->td_flags |= TDF_BOUNDARY;
|
|
}
|
|
PROC_SUNLOCK(p);
|
|
mi_switch(SW_INVOL | SWT_SUSPEND, NULL);
|
|
thread_unlock(td);
|
|
PROC_LOCK(p);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
thread_suspend_switch(struct thread *td, struct proc *p)
|
|
{
|
|
|
|
KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
/*
|
|
* We implement thread_suspend_one in stages here to avoid
|
|
* dropping the proc lock while the thread lock is owned.
|
|
*/
|
|
if (p == td->td_proc) {
|
|
thread_stopped(p);
|
|
p->p_suspcount++;
|
|
}
|
|
PROC_UNLOCK(p);
|
|
thread_lock(td);
|
|
td->td_flags &= ~TDF_NEEDSUSPCHK;
|
|
TD_SET_SUSPENDED(td);
|
|
sched_sleep(td, 0);
|
|
PROC_SUNLOCK(p);
|
|
DROP_GIANT();
|
|
mi_switch(SW_VOL | SWT_SUSPEND, NULL);
|
|
thread_unlock(td);
|
|
PICKUP_GIANT();
|
|
PROC_LOCK(p);
|
|
PROC_SLOCK(p);
|
|
}
|
|
|
|
void
|
|
thread_suspend_one(struct thread *td)
|
|
{
|
|
struct proc *p;
|
|
|
|
p = td->td_proc;
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
|
|
p->p_suspcount++;
|
|
td->td_flags &= ~TDF_NEEDSUSPCHK;
|
|
TD_SET_SUSPENDED(td);
|
|
sched_sleep(td, 0);
|
|
}
|
|
|
|
static int
|
|
thread_unsuspend_one(struct thread *td, struct proc *p, bool boundary)
|
|
{
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
|
|
TD_CLR_SUSPENDED(td);
|
|
td->td_flags &= ~TDF_ALLPROCSUSP;
|
|
if (td->td_proc == p) {
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
p->p_suspcount--;
|
|
if (boundary && (td->td_flags & TDF_BOUNDARY) != 0) {
|
|
td->td_flags &= ~TDF_BOUNDARY;
|
|
p->p_boundary_count--;
|
|
}
|
|
}
|
|
return (setrunnable(td));
|
|
}
|
|
|
|
/*
|
|
* Allow all threads blocked by single threading to continue running.
|
|
*/
|
|
void
|
|
thread_unsuspend(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
int wakeup_swapper;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
wakeup_swapper = 0;
|
|
if (!P_SHOULDSTOP(p)) {
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
if (TD_IS_SUSPENDED(td)) {
|
|
wakeup_swapper |= thread_unsuspend_one(td, p,
|
|
true);
|
|
}
|
|
thread_unlock(td);
|
|
}
|
|
} else if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
|
|
p->p_numthreads == p->p_suspcount) {
|
|
/*
|
|
* Stopping everything also did the job for the single
|
|
* threading request. Now we've downgraded to single-threaded,
|
|
* let it continue.
|
|
*/
|
|
if (p->p_singlethread->td_proc == p) {
|
|
thread_lock(p->p_singlethread);
|
|
wakeup_swapper = thread_unsuspend_one(
|
|
p->p_singlethread, p, false);
|
|
thread_unlock(p->p_singlethread);
|
|
}
|
|
}
|
|
if (wakeup_swapper)
|
|
kick_proc0();
|
|
}
|
|
|
|
/*
|
|
* End the single threading mode..
|
|
*/
|
|
void
|
|
thread_single_end(struct proc *p, int mode)
|
|
{
|
|
struct thread *td;
|
|
int wakeup_swapper;
|
|
|
|
KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY ||
|
|
mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT,
|
|
("invalid mode %d", mode));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
KASSERT((mode == SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) != 0) ||
|
|
(mode != SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) == 0),
|
|
("mode %d does not match P_TOTAL_STOP", mode));
|
|
KASSERT(mode == SINGLE_ALLPROC || p->p_singlethread == curthread,
|
|
("thread_single_end from other thread %p %p",
|
|
curthread, p->p_singlethread));
|
|
KASSERT(mode != SINGLE_BOUNDARY ||
|
|
(p->p_flag & P_SINGLE_BOUNDARY) != 0,
|
|
("mis-matched SINGLE_BOUNDARY flags %x", p->p_flag));
|
|
p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY |
|
|
P_TOTAL_STOP);
|
|
PROC_SLOCK(p);
|
|
p->p_singlethread = NULL;
|
|
wakeup_swapper = 0;
|
|
/*
|
|
* If there are other threads they may now run,
|
|
* unless of course there is a blanket 'stop order'
|
|
* on the process. The single threader must be allowed
|
|
* to continue however as this is a bad place to stop.
|
|
*/
|
|
if (p->p_numthreads != remain_for_mode(mode) && !P_SHOULDSTOP(p)) {
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
if (TD_IS_SUSPENDED(td)) {
|
|
wakeup_swapper |= thread_unsuspend_one(td, p,
|
|
mode == SINGLE_BOUNDARY);
|
|
}
|
|
thread_unlock(td);
|
|
}
|
|
}
|
|
KASSERT(mode != SINGLE_BOUNDARY || p->p_boundary_count == 0,
|
|
("inconsistent boundary count %d", p->p_boundary_count));
|
|
PROC_SUNLOCK(p);
|
|
if (wakeup_swapper)
|
|
kick_proc0();
|
|
}
|
|
|
|
struct thread *
|
|
thread_find(struct proc *p, lwpid_t tid)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
if (td->td_tid == tid)
|
|
break;
|
|
}
|
|
return (td);
|
|
}
|
|
|
|
/* Locate a thread by number; return with proc lock held. */
|
|
struct thread *
|
|
tdfind(lwpid_t tid, pid_t pid)
|
|
{
|
|
#define RUN_THRESH 16
|
|
struct thread *td;
|
|
int run = 0;
|
|
|
|
rw_rlock(&tidhash_lock);
|
|
LIST_FOREACH(td, TIDHASH(tid), td_hash) {
|
|
if (td->td_tid == tid) {
|
|
if (pid != -1 && td->td_proc->p_pid != pid) {
|
|
td = NULL;
|
|
break;
|
|
}
|
|
PROC_LOCK(td->td_proc);
|
|
if (td->td_proc->p_state == PRS_NEW) {
|
|
PROC_UNLOCK(td->td_proc);
|
|
td = NULL;
|
|
break;
|
|
}
|
|
if (run > RUN_THRESH) {
|
|
if (rw_try_upgrade(&tidhash_lock)) {
|
|
LIST_REMOVE(td, td_hash);
|
|
LIST_INSERT_HEAD(TIDHASH(td->td_tid),
|
|
td, td_hash);
|
|
rw_wunlock(&tidhash_lock);
|
|
return (td);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
run++;
|
|
}
|
|
rw_runlock(&tidhash_lock);
|
|
return (td);
|
|
}
|
|
|
|
void
|
|
tidhash_add(struct thread *td)
|
|
{
|
|
rw_wlock(&tidhash_lock);
|
|
LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
|
|
rw_wunlock(&tidhash_lock);
|
|
}
|
|
|
|
void
|
|
tidhash_remove(struct thread *td)
|
|
{
|
|
rw_wlock(&tidhash_lock);
|
|
LIST_REMOVE(td, td_hash);
|
|
rw_wunlock(&tidhash_lock);
|
|
}
|