- Add libthr but don't hook it up to the regular build yet. This is an

   adaptation of libc_r for the thr system call interface.  This is beta
   quality code.

2 files changed, 139 insertions, 0 deletions

diff --git a/lib/libthr/arch/i386/i386/_curthread.S b/lib/libthr/arch/i386/i386/_curthread.S
new file mode 100644
index 0000000..7e8dbd9
--- /dev/null
+++ b/lib/libthr/arch/i386/i386/_curthread.S
@@ -0,0 +1,17 @@
+# $FreeBSD$
+
+#include <machine/asm.h>
+
+ENTRY(_get_curthread)
+	cmpl	$0, _thread_initial
+	je	nothreads
+	movl	%gs:0, %eax
+	ret
+nothreads:
+	xor	%eax, %eax
+	ret
+
+ENTRY(_set_gs)
+	movl	4(%esp), %eax
+	movl	%eax, %gs
+	ret
diff --git a/lib/libthr/arch/i386/i386/_setcurthread.c b/lib/libthr/arch/i386/i386/_setcurthread.c
new file mode 100644
index 0000000..2e8150f
--- /dev/null
+++ b/lib/libthr/arch/i386/i386/_setcurthread.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2003, Jeffrey Roberson <jeff@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.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/types.h>
+
+#include <stdio.h>
+
+#include <machine/sysarch.h>
+#include <machine/segments.h>
+
+#define	MAXTHR	128
+
+#define	LDT_INDEX(x)	(((long)(x) - (long)ldt_entries) / sizeof(ldt_entries[0]))
+
+void **ldt_free = NULL;
+static int ldt_inited = 0;
+void *ldt_entries[MAXTHR];
+
+static void ldt_init(void);
+
+static void
+ldt_init(void)
+{
+	int i;
+
+	ldt_free = &ldt_entries[NLDT];
+
+	for (i = 0; i < MAXTHR; i++)
+		ldt_entries[i] = (void *)&ldt_entries[i + 1];
+
+	ldt_entries[MAXTHR] = NULL;
+
+	ldt_inited = 1;
+}
+
+void
+_retire_thread(void *entry)
+{
+	*(void **)entry = *ldt_free;
+	ldt_free = entry;
+}
+
+void *
+_set_curthread(void *thr)
+{
+	union descriptor desc;
+	void **ldt_entry;
+	int ldt_index;
+	int error;
+
+	if (ldt_inited == NULL)
+		ldt_init();
+
+	if (ldt_free == NULL)
+		abort();
+
+	/*
+	 * Pull one off of the free list and update the free list pointer.
+	 */
+	ldt_entry = ldt_free;
+	ldt_free = (void **)*ldt_entry;
+
+	/*
+	 * Cache the address of the thread structure here.  This is
+	 * what the gs register will point to.
+	 */
+	*ldt_entry = thr;
+	ldt_index = LDT_INDEX(ldt_entry);
+
+	bzero(&desc, sizeof(desc));
+
+	/*
+	 * Set up the descriptor to point into the ldt table which contains
+	 * only a pointer to the thread.
+	 */
+	desc.sd.sd_lolimit = sizeof(*ldt_entry);
+	desc.sd.sd_lobase = (unsigned int)ldt_entry & 0xFFFFFF;
+	desc.sd.sd_type = SDT_MEMRO;
+	desc.sd.sd_dpl = SEL_UPL;
+	desc.sd.sd_p = 1;
+	desc.sd.sd_hilimit = 0;
+	desc.sd.sd_xx = 0;
+	desc.sd.sd_def32 = 1;
+	desc.sd.sd_gran = 0;
+	desc.sd.sd_hibase = (unsigned int)ldt_entry >> 24;
+
+	error = i386_set_ldt(ldt_index, &desc, 1);
+	if (error == -1)
+		abort(); 
+
+	/*
+	 * Set up our gs with the index into the ldt for this entry.
+	 */
+	_set_gs(LSEL(ldt_index, SEL_UPL));
+
+	return (ldt_entry);
+}