509 lines
12 KiB
C
509 lines
12 KiB
C
/* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */
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/*-
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* Copyright (c) 2005 Emmanuel Dreyfus, 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, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Emmanuel Dreyfus
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* 4. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#if 0
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__KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $");
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#endif
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#include "opt_compat.h"
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/queue.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sx.h>
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#include <sys/malloc.h>
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#ifdef COMPAT_LINUX32
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#include <machine/../linux32/linux.h>
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#include <machine/../linux32/linux32_proto.h>
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#else
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#include <machine/../linux/linux.h>
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#include <machine/../linux/linux_proto.h>
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#endif
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#include <compat/linux/linux_futex.h>
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struct futex;
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struct waiting_proc {
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struct thread *wp_t;
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struct futex *wp_new_futex;
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TAILQ_ENTRY(waiting_proc) wp_list;
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};
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struct futex {
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void *f_uaddr;
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int f_refcount;
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LIST_ENTRY(futex) f_list;
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TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
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};
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LIST_HEAD(futex_list, futex) futex_list;
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struct sx futex_sx; /* this protects the LIST of futexes */
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#define FUTEX_LOCK sx_xlock(&futex_sx)
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#define FUTEX_UNLOCK sx_xunlock(&futex_sx)
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#define FUTEX_LOCKED 1
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#define FUTEX_UNLOCKED 0
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#define FUTEX_SYSTEM_LOCK mtx_lock(&Giant)
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#define FUTEX_SYSTEM_UNLOCK mtx_unlock(&Giant)
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static struct futex *futex_get(void *, int);
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static void futex_put(struct futex *);
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static int futex_sleep(struct futex *, struct thread *, unsigned long);
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static int futex_wake(struct futex *, int, struct futex *);
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#ifdef __i386__
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static int futex_atomic_op(struct thread *td, int encoded_op, caddr_t uaddr);
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#endif
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/* support.s */
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int futex_xchgl(int oparg, caddr_t uaddr, int *oldval);
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int futex_addl(int oparg, caddr_t uaddr, int *oldval);
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int futex_orl(int oparg, caddr_t uaddr, int *oldval);
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int futex_andnl(int oparg, caddr_t uaddr, int *oldval);
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int futex_xorl(int oparg, caddr_t uaddr, int *oldval);
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int
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linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
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{
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int val;
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int ret;
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struct l_timespec timeout = {0, 0};
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int error = 0;
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struct futex *f;
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struct futex *newf;
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int timeout_hz;
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struct timeval tv = {0, 0};
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#ifdef __i386__
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struct futex *f2;
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int op_ret;
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#endif
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf(ARGS(futex, "%p, %i, %i"), args->uaddr, args->op,
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args->val);
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#endif
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switch (args->op) {
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case LINUX_FUTEX_WAIT:
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FUTEX_SYSTEM_LOCK;
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if ((error = copyin(args->uaddr,
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&val, sizeof(val))) != 0) {
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FUTEX_SYSTEM_UNLOCK;
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return error;
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}
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if (val != args->val) {
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FUTEX_SYSTEM_UNLOCK;
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return EWOULDBLOCK;
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}
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if (args->timeout != NULL) {
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if ((error = copyin(args->timeout,
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&timeout, sizeof(timeout))) != 0) {
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FUTEX_SYSTEM_UNLOCK;
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return error;
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}
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}
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX_WAIT %d: val = %d, uaddr = %p, "
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"*uaddr = %d, timeout = %d.%09lu\n",
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td->td_proc->p_pid, args->val,
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args->uaddr, val, timeout.tv_sec,
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(unsigned long)timeout.tv_nsec);
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#endif
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tv.tv_usec = timeout.tv_sec * 1000000 + timeout.tv_nsec / 1000;
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timeout_hz = tvtohz(&tv);
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if (timeout.tv_sec == 0 && timeout.tv_nsec == 0)
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timeout_hz = 0;
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/*
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* If the user process requests a non null timeout,
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* make sure we do not turn it into an infinite
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* timeout because timeout_hz gets null.
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*
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* We use a minimal timeout of 1/hz. Maybe it would
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* make sense to just return ETIMEDOUT without sleeping.
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*/
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if (((timeout.tv_sec != 0) || (timeout.tv_nsec != 0)) &&
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(timeout_hz == 0))
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timeout_hz = 1;
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f = futex_get(args->uaddr, FUTEX_UNLOCKED);
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ret = futex_sleep(f, td, timeout_hz);
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futex_put(f);
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX_WAIT %d: uaddr = %p, "
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"ret = %d\n", td->td_proc->p_pid, args->uaddr, ret);
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#endif
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FUTEX_SYSTEM_UNLOCK;
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switch (ret) {
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case EWOULDBLOCK: /* timeout */
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return ETIMEDOUT;
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break;
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case EINTR: /* signal */
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return EINTR;
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break;
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case 0: /* FUTEX_WAKE received */
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX_WAIT %d: uaddr = %p, got FUTEX_WAKE\n",
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td->td_proc->p_pid, args->uaddr);
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#endif
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return 0;
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break;
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default:
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX_WAIT: unexpected ret = %d\n", ret);
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#endif
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break;
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}
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/* NOTREACHED */
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break;
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case LINUX_FUTEX_WAKE:
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FUTEX_SYSTEM_LOCK;
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/*
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* XXX: Linux is able cope with different addresses
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* corresponding to the same mapped memory in the sleeping
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* and the waker process.
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*/
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX_WAKE %d: uaddr = %p, val = %d\n",
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td->td_proc->p_pid, args->uaddr, args->val);
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#endif
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f = futex_get(args->uaddr, FUTEX_UNLOCKED);
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td->td_retval[0] = futex_wake(f, args->val, NULL);
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futex_put(f);
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FUTEX_SYSTEM_UNLOCK;
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break;
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case LINUX_FUTEX_CMP_REQUEUE:
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FUTEX_SYSTEM_LOCK;
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if ((error = copyin(args->uaddr,
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&val, sizeof(val))) != 0) {
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FUTEX_SYSTEM_UNLOCK;
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return error;
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}
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if (val != args->val3) {
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FUTEX_SYSTEM_UNLOCK;
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return EAGAIN;
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}
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f = futex_get(args->uaddr, FUTEX_UNLOCKED);
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newf = futex_get(args->uaddr2, FUTEX_UNLOCKED);
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td->td_retval[0] = futex_wake(f, args->val, newf);
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futex_put(f);
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futex_put(newf);
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FUTEX_SYSTEM_UNLOCK;
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break;
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case LINUX_FUTEX_REQUEUE:
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FUTEX_SYSTEM_LOCK;
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f = futex_get(args->uaddr, FUTEX_UNLOCKED);
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newf = futex_get(args->uaddr2, FUTEX_UNLOCKED);
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td->td_retval[0] = futex_wake(f, args->val, newf);
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futex_put(f);
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futex_put(newf);
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FUTEX_SYSTEM_UNLOCK;
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break;
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case LINUX_FUTEX_FD:
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printf("linux_sys_futex: unimplemented op %d\n",
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args->op);
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break;
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case LINUX_FUTEX_WAKE_OP:
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#ifdef __i386__
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FUTEX_SYSTEM_LOCK;
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX_WAKE_OP: %d: uaddr = %p, op = %d, val = %d, uaddr2 = %p, val3 = %d\n",
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td->td_proc->p_pid, args->uaddr, args->op, args->val,
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args->uaddr2, args->val3);
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#endif
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f = futex_get(args->uaddr, FUTEX_UNLOCKED);
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f2 = futex_get(args->uaddr2, FUTEX_UNLOCKED);
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/*
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* This function returns positive number as results and
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* negative as errors
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*/
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op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
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if (op_ret < 0) {
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/* XXX: we dont handle the EFAULT yet */
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if (op_ret != -EFAULT) {
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futex_put(f);
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futex_put(f2);
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FUTEX_SYSTEM_UNLOCK;
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return (-op_ret);
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}
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futex_put(f);
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futex_put(f2);
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FUTEX_SYSTEM_UNLOCK;
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return (EFAULT);
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}
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ret = futex_wake(f, args->val, NULL);
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futex_put(f);
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if (op_ret > 0) {
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op_ret = 0;
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/*
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* Linux uses the address of the timespec parameter
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* as the number of retries, so any large number will
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* be ok.
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*/
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op_ret += futex_wake(f2, 0x7fffffff, NULL);
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ret += op_ret;
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}
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futex_put(f2);
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td->td_retval[0] = ret;
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FUTEX_SYSTEM_UNLOCK;
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#else
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printf("linux_sys_futex: wake_op not implemented");
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#endif
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break;
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default:
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printf("linux_sys_futex: unknown op %d\n",
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args->op);
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break;
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}
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return 0;
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}
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static struct futex *
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futex_get(void *uaddr, int locked)
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{
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struct futex *f;
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if (locked == FUTEX_UNLOCKED)
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FUTEX_LOCK;
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LIST_FOREACH(f, &futex_list, f_list) {
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if (f->f_uaddr == uaddr) {
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f->f_refcount++;
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if (locked == FUTEX_UNLOCKED)
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FUTEX_UNLOCK;
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return f;
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}
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}
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f = malloc(sizeof(*f), M_LINUX, M_WAITOK);
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f->f_uaddr = uaddr;
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f->f_refcount = 1;
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TAILQ_INIT(&f->f_waiting_proc);
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LIST_INSERT_HEAD(&futex_list, f, f_list);
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if (locked == FUTEX_UNLOCKED)
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FUTEX_UNLOCK;
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return f;
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}
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static void
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futex_put(f)
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struct futex *f;
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{
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FUTEX_LOCK;
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f->f_refcount--;
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if (f->f_refcount == 0) {
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LIST_REMOVE(f, f_list);
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free(f, M_LINUX);
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}
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FUTEX_UNLOCK;
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return;
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}
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static int
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futex_sleep(struct futex *f, struct thread *td, unsigned long timeout)
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{
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struct waiting_proc *wp;
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int ret;
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wp = malloc(sizeof(*wp), M_LINUX, M_WAITOK);
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wp->wp_t = td;
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wp->wp_new_futex = NULL;
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FUTEX_LOCK;
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TAILQ_INSERT_TAIL(&f->f_waiting_proc, wp, wp_list);
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FUTEX_UNLOCK;
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX --> %d tlseep timeout = %ld\n", td->td_proc->p_pid,
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timeout);
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#endif
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ret = tsleep(wp, PCATCH | PZERO, "linuxfutex", timeout);
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#ifdef DEBUG
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if (ldebug(sys_futex))
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printf("FUTEX -> %d tsleep returns %d\n",
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td->td_proc->p_pid, ret);
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#endif
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FUTEX_LOCK;
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TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
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FUTEX_UNLOCK;
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if ((ret == 0) && (wp->wp_new_futex != NULL)) {
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ret = futex_sleep(wp->wp_new_futex, td, timeout);
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futex_put(wp->wp_new_futex); /* futex_get called in wakeup */
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}
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free(wp, M_LINUX);
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return ret;
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}
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static int
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futex_wake(struct futex *f, int n, struct futex *newf)
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{
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struct waiting_proc *wp;
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int count = 0;
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FUTEX_LOCK;
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TAILQ_FOREACH(wp, &f->f_waiting_proc, wp_list) {
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if (count <= n) {
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wakeup_one(wp);
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count++;
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} else {
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if (newf != NULL) {
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/* futex_put called after tsleep */
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wp->wp_new_futex = futex_get(newf->f_uaddr, FUTEX_LOCKED);
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wakeup_one(wp);
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}
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}
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}
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FUTEX_UNLOCK;
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return count;
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}
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#ifdef __i386__
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static int
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futex_atomic_op(struct thread *td, int encoded_op, caddr_t uaddr)
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{
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int op = (encoded_op >> 28) & 7;
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int cmp = (encoded_op >> 24) & 15;
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int oparg = (encoded_op << 8) >> 20;
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int cmparg = (encoded_op << 20) >> 20;
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int oldval = 0, ret;
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if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
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oparg = 1 << oparg;
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#ifdef DEBUG
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printf("futex_atomic_op: op = %d, cmp = %d, oparg = %d, cmparg = %d, uaddr = %p\n",
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op, cmp, oparg, cmparg, uaddr);
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#endif
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/* XXX: linux verifies access here and returns EFAULT */
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critical_enter();
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switch (op) {
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case FUTEX_OP_SET:
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ret = futex_xchgl(oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_ADD:
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ret = futex_addl(oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_OR:
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ret = futex_orl(oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_ANDN:
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ret = futex_andnl(oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_XOR:
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ret = futex_xorl(oparg, uaddr, &oldval);
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break;
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default:
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ret = -ENOSYS;
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}
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critical_exit();
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if (!ret)
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switch (cmp) {
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case FUTEX_OP_CMP_EQ:
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ret = (oldval == cmparg);
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break;
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case FUTEX_OP_CMP_NE:
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ret = (oldval != cmparg);
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break;
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case FUTEX_OP_CMP_LT:
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ret = (oldval < cmparg);
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break;
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case FUTEX_OP_CMP_GE:
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ret = (oldval >= cmparg);
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break;
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case FUTEX_OP_CMP_LE:
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ret = (oldval <= cmparg);
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break;
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case FUTEX_OP_CMP_GT:
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ret = (oldval > cmparg);
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break;
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default: ret = -ENOSYS;
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}
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return (ret);
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}
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#endif
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