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Diffstat (limited to 'sys/compat/linux/linux_futex.c')
-rw-r--r--sys/compat/linux/linux_futex.c500
1 files changed, 500 insertions, 0 deletions
diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
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+++ b/sys/compat/linux/linux_futex.c
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+/* $NetBSD: linux_futex.c,v 1.5 2005/11/23 16:14:57 manu Exp $ */
+
+/*-
+ * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by Emmanuel Dreyfus
+ * 4. The name of the author may not be used to endorse or promote
+ * products derived from this software without specific prior written
+ * permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+#if 0
+ __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.5 2005/11/23 16:14:57 manu Exp $");
+#endif
+
+#include "opt_compat.h"
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/queue.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/malloc.h>
+
+#ifdef COMPAT_LINUX32
+#include <machine/../linux32/linux.h>
+#include <machine/../linux32/linux32_proto.h>
+#else
+#include <machine/../linux/linux.h>
+#include <machine/../linux/linux_proto.h>
+#endif
+#include <compat/linux/linux_futex.h>
+
+struct futex;
+
+struct waiting_proc {
+ struct thread *wp_t;
+ struct futex *wp_new_futex;
+ TAILQ_ENTRY(waiting_proc) wp_list;
+};
+struct futex {
+ void *f_uaddr;
+ int f_refcount;
+ LIST_ENTRY(futex) f_list;
+ TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
+};
+
+LIST_HEAD(futex_list, futex) futex_list;
+struct mtx futex_mtx; /* this protects the LIST of futexes */
+
+#define FUTEX_LOCK mtx_lock(&futex_mtx)
+#define FUTEX_UNLOCK mtx_unlock(&futex_mtx)
+
+#define FUTEX_LOCKED 1
+#define FUTEX_UNLOCKED 0
+
+#define FUTEX_SYSTEM_LOCK mtx_lock(&Giant)
+#define FUTEX_SYSTEM_UNLOCK mtx_unlock(&Giant)
+
+static struct futex *futex_get(void *, int);
+static void futex_put(struct futex *);
+static int futex_sleep(struct futex *, struct thread *, unsigned long);
+static int futex_wake(struct futex *, int, struct futex *);
+#ifdef __i386__
+static int futex_atomic_op(struct thread *td, int encoded_op, caddr_t uaddr);
+#endif
+
+/* support.s */
+int futex_xchgl(int oparg, caddr_t uaddr, int *oldval);
+int futex_addl(int oparg, caddr_t uaddr, int *oldval);
+int futex_orl(int oparg, caddr_t uaddr, int *oldval);
+int futex_andnl(int oparg, caddr_t uaddr, int *oldval);
+int futex_xorl(int oparg, caddr_t uaddr, int *oldval);
+
+int
+linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
+{
+ int val;
+ int ret;
+ struct l_timespec timeout = { 0, 0 };
+ int error = 0;
+ struct futex *f;
+ struct futex *newf;
+ int timeout_hz;
+ struct timeval tv = {0, 0};
+#ifdef __i386__
+ struct futex *f2;
+ int op_ret;
+#endif
+
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf(ARGS(futex,"%p, %i, %i"), args->uaddr, args->op, args->val);
+#endif
+
+ switch (args->op) {
+ case LINUX_FUTEX_WAIT:
+ FUTEX_SYSTEM_LOCK;
+
+ if ((error = copyin(args->uaddr,
+ &val, sizeof(val))) != 0) {
+ FUTEX_SYSTEM_UNLOCK;
+ return error;
+ }
+
+ if (val != args->val) {
+ FUTEX_SYSTEM_UNLOCK;
+ return EWOULDBLOCK;
+ }
+
+ if (args->timeout != NULL) {
+ if ((error = copyin(args->timeout,
+ &timeout, sizeof(timeout))) != 0) {
+ FUTEX_SYSTEM_UNLOCK;
+ return error;
+ }
+ }
+
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf("FUTEX_WAIT %d: val = %d, uaddr = %p, "
+ "*uaddr = %d, timeout = %d.%09ld\n",
+ td->td_proc->p_pid, args->val,
+ args->uaddr, val, timeout.tv_sec, timeout.tv_nsec);
+#endif
+ tv.tv_usec = timeout.tv_sec * 1000000 + timeout.tv_nsec / 1000;
+ timeout_hz = tvtohz(&tv);
+
+ if (timeout.tv_sec == 0 && timeout.tv_nsec == 0)
+ timeout_hz = 0;
+ /*
+ * If the user process requests a non null timeout,
+ * make sure we do not turn it into an infinite
+ * timeout because timeout_hz gets null.
+ *
+ * We use a minimal timeout of 1/hz. Maybe it would
+ * make sense to just return ETIMEDOUT without sleeping.
+ */
+ if (((timeout.tv_sec != 0) || (timeout.tv_nsec != 0)) &&
+ (timeout_hz == 0))
+ timeout_hz = 1;
+
+
+ f = futex_get(args->uaddr, FUTEX_UNLOCKED);
+ ret = futex_sleep(f, td, timeout_hz);
+ futex_put(f);
+
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf("FUTEX_WAIT %d: uaddr = %p, "
+ "ret = %d\n", td->td_proc->p_pid, args->uaddr, ret);
+#endif
+
+ FUTEX_SYSTEM_UNLOCK;
+ switch (ret) {
+ case EWOULDBLOCK: /* timeout */
+ return ETIMEDOUT;
+ break;
+ case EINTR: /* signal */
+ return EINTR;
+ break;
+ case 0: /* FUTEX_WAKE received */
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf("FUTEX_WAIT %d: uaddr = %p, got FUTEX_WAKE\n",
+ td->td_proc->p_pid, args->uaddr);
+#endif
+ return 0;
+ break;
+ default:
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf("FUTEX_WAIT: unexpected ret = %d\n", ret);
+#endif
+ break;
+ }
+
+ /* NOTREACHED */
+ break;
+
+ case LINUX_FUTEX_WAKE:
+ FUTEX_SYSTEM_LOCK;
+
+ /*
+ * XXX: Linux is able cope with different addresses
+ * corresponding to the same mapped memory in the sleeping
+ * and the waker process.
+ */
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf("FUTEX_WAKE %d: uaddr = %p, val = %d\n",
+ td->td_proc->p_pid, args->uaddr, args->val);
+#endif
+ f = futex_get(args->uaddr, FUTEX_UNLOCKED);
+ td->td_retval[0] = futex_wake(f, args->val, NULL);
+ futex_put(f);
+
+ FUTEX_SYSTEM_UNLOCK;
+ break;
+
+ case LINUX_FUTEX_CMP_REQUEUE:
+ FUTEX_SYSTEM_LOCK;
+
+ if ((error = copyin(args->uaddr,
+ &val, sizeof(val))) != 0) {
+ FUTEX_SYSTEM_UNLOCK;
+ return error;
+ }
+
+ if (val != args->val3) {
+ FUTEX_SYSTEM_UNLOCK;
+ return EAGAIN;
+ }
+
+ f = futex_get(args->uaddr, FUTEX_UNLOCKED);
+ newf = futex_get(args->uaddr2, FUTEX_UNLOCKED);
+ td->td_retval[0] = futex_wake(f, args->val, newf);
+ futex_put(f);
+ futex_put(newf);
+
+ FUTEX_SYSTEM_UNLOCK;
+ break;
+
+ case LINUX_FUTEX_REQUEUE:
+ FUTEX_SYSTEM_LOCK;
+
+ f = futex_get(args->uaddr, FUTEX_UNLOCKED);
+ newf = futex_get(args->uaddr2, FUTEX_UNLOCKED);
+ td->td_retval[0] = futex_wake(f, args->val, newf);
+ futex_put(f);
+ futex_put(newf);
+
+ FUTEX_SYSTEM_UNLOCK;
+ break;
+
+ case LINUX_FUTEX_FD:
+ printf("linux_sys_futex: unimplemented op %d\n",
+ args->op);
+ break;
+
+ case LINUX_FUTEX_WAKE_OP:
+#ifdef __i386__
+ FUTEX_SYSTEM_LOCK;
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf("FUTEX_WAKE_OP: %d: uaddr = %p, op = %d, val = %d, uaddr2 = %p, val3 = %d\n",
+ td->td_proc->p_pid, args->uaddr, args->op, args->val, args->uaddr2, args->val3);
+#endif
+ f = futex_get(args->uaddr, FUTEX_UNLOCKED);
+ f2 = futex_get(args->uaddr2, FUTEX_UNLOCKED);
+
+ /* This function returns positive number as results
+ * and negative as errors
+ */
+ op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
+ if (op_ret < 0) {
+
+ /* XXX: we dont handle the EFAULT yet */
+ if (op_ret != -EFAULT) {
+ futex_put(f);
+ futex_put(f2);
+ FUTEX_SYSTEM_UNLOCK;
+ return (-op_ret);
+ }
+
+ futex_put(f);
+ futex_put(f2);
+
+ FUTEX_SYSTEM_UNLOCK;
+ return (EFAULT);
+
+ }
+
+ ret = futex_wake(f, args->val, NULL);
+ futex_put(f);
+ if (op_ret > 0) {
+ printf("second wakeup\n");
+ op_ret = 0;
+ /* Linux always puts there 0 retries */
+ op_ret += futex_wake(f2, 0, NULL);
+ ret += op_ret;
+ }
+ futex_put(f2);
+ td->td_retval[0] = ret;
+
+ FUTEX_SYSTEM_UNLOCK;
+#else
+ printf("linux_sys_futex: wake_op not implemented");
+#endif
+ break;
+
+ default:
+ printf("linux_sys_futex: unknown op %d\n",
+ args->op);
+ break;
+ }
+ return 0;
+}
+
+static struct futex *
+futex_get(void *uaddr, int locked)
+{
+ struct futex *f;
+
+ if (locked == FUTEX_UNLOCKED)
+ FUTEX_LOCK;
+ LIST_FOREACH(f, &futex_list, f_list) {
+ if (f->f_uaddr == uaddr) {
+ f->f_refcount++;
+ if (locked == FUTEX_UNLOCKED)
+ FUTEX_UNLOCK;
+ return f;
+ }
+ }
+ if (locked == FUTEX_UNLOCKED)
+ FUTEX_UNLOCK;
+
+ /* Not found, create it */
+ f = malloc(sizeof(*f), M_LINUX, M_WAITOK);
+ f->f_uaddr = uaddr;
+ f->f_refcount = 1;
+ TAILQ_INIT(&f->f_waiting_proc);
+ if (locked == FUTEX_UNLOCKED)
+ FUTEX_LOCK;
+ LIST_INSERT_HEAD(&futex_list, f, f_list);
+ if (locked == FUTEX_UNLOCKED)
+ FUTEX_UNLOCK;
+
+ return f;
+}
+
+static void
+futex_put(f)
+ struct futex *f;
+{
+ FUTEX_LOCK;
+ f->f_refcount--;
+ if (f->f_refcount == 0) {
+ LIST_REMOVE(f, f_list);
+ free(f, M_LINUX);
+ }
+ FUTEX_UNLOCK;
+
+ return;
+}
+
+static int
+futex_sleep(struct futex *f, struct thread *td, unsigned long timeout)
+{
+ struct waiting_proc *wp;
+ int ret;
+
+ wp = malloc(sizeof(*wp), M_LINUX, M_WAITOK);
+ wp->wp_t = td;
+ wp->wp_new_futex = NULL;
+ FUTEX_LOCK;
+ TAILQ_INSERT_TAIL(&f->f_waiting_proc, wp, wp_list);
+ FUTEX_UNLOCK;
+
+#ifdef DEBUG
+ if (ldebug(sys_futex))
+ printf("FUTEX --> %d tlseep timeout = %ld\n", td->td_proc->p_pid,
+ timeout);
+#endif
+ ret = tsleep(wp, PCATCH|PZERO, "linuxfutex", timeout);
+
+ FUTEX_LOCK;
+ TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
+ FUTEX_UNLOCK;
+
+ if ((ret == 0) && (wp->wp_new_futex != NULL)) {
+ ret = futex_sleep(wp->wp_new_futex, td, timeout);
+ futex_put(wp->wp_new_futex); /* futex_get called in wakeup */
+ }
+
+ free(wp, M_LINUX);
+
+ return ret;
+}
+
+static int
+futex_wake(struct futex *f, int n, struct futex *newf)
+{
+ struct waiting_proc *wp;
+ int count = 0;
+
+ FUTEX_LOCK;
+ TAILQ_FOREACH(wp, &f->f_waiting_proc, wp_list) {
+ if (count <= n) {
+ wakeup(wp);
+ count++;
+ } else {
+ if (newf != NULL) {
+ /* futex_put called after tsleep */
+ wp->wp_new_futex = futex_get(newf->f_uaddr, FUTEX_LOCKED);
+ wakeup(wp);
+ }
+ }
+ }
+ FUTEX_UNLOCK;
+
+ return count;
+}
+
+#ifdef __i386__
+static int
+futex_atomic_op(struct thread *td, int encoded_op, caddr_t uaddr)
+{
+ int op = (encoded_op >> 28) & 7;
+ int cmp = (encoded_op >> 24) & 15;
+ int oparg = (encoded_op << 8) >> 20;
+ int cmparg = (encoded_op << 20) >> 20;
+ int oldval = 0, ret;
+
+ if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+ oparg = 1 << oparg;
+
+#ifdef DEBUG
+ printf("futex_atomic_op: op = %d, cmp = %d, oparg = %d, cmparg = %d, uaddr = %p\n",
+ op, cmp, oparg, cmparg, uaddr);
+#endif
+ /* XXX: linux verifies access here and returns EFAULT */
+
+ critical_enter();
+
+ switch (op) {
+ case FUTEX_OP_SET:
+ ret = futex_xchgl(oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_ADD:
+ ret = futex_addl(oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_OR:
+ ret = futex_orl(oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_ANDN:
+ ret = futex_andnl(oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_XOR:
+ ret = futex_xorl(oparg, uaddr, &oldval);
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+
+ critical_exit();
+
+ if (!ret)
+ switch (cmp) {
+ case FUTEX_OP_CMP_EQ:
+ ret = (oldval == cmparg);
+ break;
+ case FUTEX_OP_CMP_NE:
+ ret = (oldval != cmparg);
+ break;
+ case FUTEX_OP_CMP_LT:
+ ret = (oldval < cmparg);
+ break;
+ case FUTEX_OP_CMP_GE:
+ ret = (oldval >= cmparg);
+ break;
+ case FUTEX_OP_CMP_LE:
+ ret = (oldval <= cmparg);
+ break;
+ case FUTEX_OP_CMP_GT:
+ ret = (oldval > cmparg);
+ break;
+ default: ret = -ENOSYS;
+ }
+
+ return (ret);
+}
+#endif
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