sparc support code for librthread (_atomic_lock yanked from existing

libpthread code).

2 files changed, 114 insertions, 0 deletions

diff --git a/lib/librthread/arch/sparc/_atomic_lock.c b/lib/librthread/arch/sparc/_atomic_lock.c
new file mode 100644
index 00000000000..c791314c8d1
--- /dev/null
+++ b/lib/librthread/arch/sparc/_atomic_lock.c
@@ -0,0 +1,41 @@
+/*	$OpenBSD: _atomic_lock.c,v 1.1 2005/12/25 16:00:02 miod Exp $	*/
+/*
+ * Atomic lock for sparc
+ */
+ 
+#include <machine/spinlock.h>
+
+int
+_atomic_lock(volatile _spinlock_lock_t * lock)
+{
+	_spinlock_lock_t old;
+
+	/*
+	 *  "  ldstub  [address], reg_rd
+	 * 
+	 *  The atomic load-store instructions copy a byte from memory
+	 *  into r[rd]m then rewrite the addressed byte in memory to all
+	 *  ones [_SPINLOCK_LOCKED]. The operation is performed
+	 *  atomically, that is, without allowing intervening interrupts
+	 *  or deferred traps. In a multiprocessor system, two or more
+	 *  processors executing atomic load-store unsigned byte [...]
+	 *  addressing the same byte [...] simultaneously are guaranteed
+	 *  to execute them in an undefined, but serial order."
+	 *    - p101, The SPARC Architecture Manual (version 8) Prentice-Hall
+	 *
+	 * "LDSTUB loads a byte value from memory to a register and writes
+	 *  the value FF_16 into the addressed byte atomically. LDSTUB
+	 *  is the classic test-and-set instruction. Like SWAP, it has
+	 *  a consensus number of two and so cannot resolve more than
+	 *  two contending processes in a wait-free fashion."
+	 *    - p129, The SPARC Architecture Manual (version 9) Prentice-Hall
+	 *  (See also section J.6 (spinlocks))
+	 *
+	 * (No change to the condition codes are documented.)
+	 */
+	__asm__("ldstub %0,%1"
+		: "=m" (*lock), "=r" (old)
+		: "0" (*lock));
+
+	return (old == _SPINLOCK_LOCKED);
+}
diff --git a/lib/librthread/arch/sparc/rfork_thread.S b/lib/librthread/arch/sparc/rfork_thread.S
new file mode 100644
index 00000000000..a7dc8135e88
--- /dev/null
+++ b/lib/librthread/arch/sparc/rfork_thread.S
@@ -0,0 +1,73 @@
+/*	$OpenBSD: rfork_thread.S,v 1.1 2005/12/25 16:00:02 miod Exp $	*/
+
+/*
+ * Copyright (c) 2005, Miodrag Vallat
+ *
+ * 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.
+ *
+ * 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.
+ */
+
+#include "../../../libc/arch/sparc/SYS.h"
+
+/*
+ * int rfork_thread(int flags, void *stack, void (*func)(void *), void *arg);
+ */
+ENTRY(rfork_thread)
+	mov	%o1, %o4	/* save stack */
+
+	/*
+	 * We can not invoke rfork as a G2-style system call since we want
+	 * different return paths.
+	  */
+	mov	SYS_rfork, %g1
+	t	ST_SYSCALL
+	bcs	9f
+	 nop
+
+	cmp	%o0, 0
+	be	1f
+	 nop
+
+	/*
+	 * In parent process: just return.
+	 */
+	retl
+	 nop
+
+1:
+	/*
+	 * In child process: switch stack, invoke function, then exit.
+	 * Don't forget to allocate room for a window save on the new
+	 * stack!
+	 */
+	sub	%o4, 64, %sp	/* stack */
+	call	%o2		/* func */
+	 mov	%o3, %o0	/* arg */
+
+	mov	SYS_threxit, %g1
+	clr	%o0
+	t	ST_SYSCALL	/* will not return */
+
+9:
+	/*
+	 * System call failure.
+	 */
+	ERROR()