[Midnightbsd-cvs] src: thr_rtld.c: update libthr
laffer1 at midnightbsd.org
laffer1 at midnightbsd.org
Thu Oct 2 12:56:52 EDT 2008
Log Message:
-----------
update libthr
Added Files:
-----------
src/lib/libthr/thread:
thr_rtld.c (r1.1)
-------------- next part --------------
--- /dev/null
+++ lib/libthr/thread/thr_rtld.c
@@ -0,0 +1,219 @@
+/*
+ * Copyright (c) 2006, David Xu <davidxu at freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice unmodified, this list of conditions, and the following
+ * disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD: src/lib/libthr/thread/thr_rtld.c,v 1.3 2006/04/04 02:57:49 davidxu Exp $
+ *
+ */
+
+ /*
+ * A lockless rwlock for rtld.
+ */
+#include <sys/cdefs.h>
+#include <stdlib.h>
+
+#include "rtld_lock.h"
+#include "thr_private.h"
+
+#define CACHE_LINE_SIZE 64
+#define WAFLAG 0x1
+#define RC_INCR 0x2
+
+static int _thr_rtld_clr_flag(int);
+static void *_thr_rtld_lock_create(void);
+static void _thr_rtld_lock_destroy(void *);
+static void _thr_rtld_lock_release(void *);
+static void _thr_rtld_rlock_acquire(void *);
+static int _thr_rtld_set_flag(int);
+static void _thr_rtld_wlock_acquire(void *);
+
+struct rtld_lock {
+ volatile int lock;
+ volatile int rd_waiters;
+ volatile int wr_waiters;
+ volatile umtx_t rd_cv;
+ volatile umtx_t wr_cv;
+ void *base;
+};
+
+static void *
+_thr_rtld_lock_create(void)
+{
+ void *base;
+ char *p;
+ uintptr_t r;
+ struct rtld_lock *l;
+
+ THR_ASSERT(sizeof(struct rtld_lock) <= CACHE_LINE_SIZE,
+ "rtld_lock too large");
+ base = calloc(1, CACHE_LINE_SIZE);
+ p = (char *)base;
+ if ((uintptr_t)p % CACHE_LINE_SIZE != 0) {
+ free(base);
+ base = calloc(1, 2 * CACHE_LINE_SIZE);
+ p = (char *)base;
+ if ((r = (uintptr_t)p % CACHE_LINE_SIZE) != 0)
+ p += CACHE_LINE_SIZE - r;
+ }
+ l = (struct rtld_lock *)p;
+ l->base = base;
+ return (l);
+}
+
+static void
+_thr_rtld_lock_destroy(void *lock)
+{
+ struct rtld_lock *l = (struct rtld_lock *)lock;
+ free(l->base);
+}
+
+static void
+_thr_rtld_rlock_acquire(void *lock)
+{
+ struct pthread *curthread;
+ struct rtld_lock *l;
+ umtx_t v;
+
+ curthread = _get_curthread();
+ l = (struct rtld_lock *)lock;
+
+ THR_CRITICAL_ENTER(curthread);
+ atomic_add_acq_int(&l->lock, RC_INCR);
+ if (!(l->lock & WAFLAG))
+ return;
+ v = l->rd_cv;
+ atomic_add_int(&l->rd_waiters, 1);
+ while (l->lock & WAFLAG) {
+ _thr_umtx_wait(&l->rd_cv, v, NULL);
+ v = l->rd_cv;
+ }
+ atomic_add_int(&l->rd_waiters, -1);
+}
+
+static void
+_thr_rtld_wlock_acquire(void *lock)
+{
+ struct pthread *curthread;
+ struct rtld_lock *l;
+ umtx_t v;
+
+ curthread = _get_curthread();
+ l = (struct rtld_lock *)lock;
+
+ _thr_signal_block(curthread);
+ for (;;) {
+ if (atomic_cmpset_acq_int(&l->lock, 0, WAFLAG))
+ return;
+ v = l->wr_cv;
+ atomic_add_int(&l->wr_waiters, 1);
+ while (l->lock != 0) {
+ _thr_umtx_wait(&l->wr_cv, v, NULL);
+ v = l->wr_cv;
+ }
+ atomic_add_int(&l->wr_waiters, -1);
+ }
+}
+
+static void
+_thr_rtld_lock_release(void *lock)
+{
+ struct pthread *curthread;
+ struct rtld_lock *l;
+
+ curthread = _get_curthread();
+ l = (struct rtld_lock *)lock;
+
+ if ((l->lock & WAFLAG) == 0) {
+ atomic_add_rel_int(&l->lock, -RC_INCR);
+ if (l->lock == 0 && l->wr_waiters) {
+ atomic_add_long(&l->wr_cv, 1);
+ _thr_umtx_wake(&l->wr_cv, l->wr_waiters);
+ }
+ THR_CRITICAL_LEAVE(curthread);
+ } else {
+ atomic_add_rel_int(&l->lock, -WAFLAG);
+ if (l->lock == 0 && l->wr_waiters) {
+ atomic_add_long(&l->wr_cv, 1);
+ _thr_umtx_wake(&l->wr_cv, l->wr_waiters);
+ } else if (l->rd_waiters) {
+ atomic_add_long(&l->rd_cv, 1);
+ _thr_umtx_wake(&l->rd_cv, l->rd_waiters);
+ }
+ _thr_signal_unblock(curthread);
+ }
+}
+
+static int
+_thr_rtld_set_flag(int mask __unused)
+{
+ /*
+ * The caller's code in rtld-elf is broken, it is not signal safe,
+ * just return zero to fool it.
+ */
+ return (0);
+}
+
+static int
+_thr_rtld_clr_flag(int mask __unused)
+{
+ return (0);
+}
+
+void
+_thr_rtld_init(void)
+{
+ struct RtldLockInfo li;
+ struct pthread *curthread;
+ umtx_t dummy;
+
+ curthread = _get_curthread();
+
+ /* force to resolve _umtx_op PLT */
+ _umtx_op((struct umtx *)&dummy, UMTX_OP_WAKE, 1, 0, 0);
+
+ li.lock_create = _thr_rtld_lock_create;
+ li.lock_destroy = _thr_rtld_lock_destroy;
+ li.rlock_acquire = _thr_rtld_rlock_acquire;
+ li.wlock_acquire = _thr_rtld_wlock_acquire;
+ li.lock_release = _thr_rtld_lock_release;
+ li.thread_set_flag = _thr_rtld_set_flag;
+ li.thread_clr_flag = _thr_rtld_clr_flag;
+ li.at_fork = NULL;
+
+ /* mask signals, also force to resolve __sys_sigprocmask PLT */
+ _thr_signal_block(curthread);
+ _rtld_thread_init(&li);
+ _thr_signal_unblock(curthread);
+}
+
+void
+_thr_rtld_fini(void)
+{
+ struct pthread *curthread;
+
+ curthread = _get_curthread();
+ _thr_signal_block(curthread);
+ _rtld_thread_init(NULL);
+ _thr_signal_unblock(curthread);
+}
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