Implement a slightly different window spill/fill algorithm for dealing

with user windows in kernel mode.  We split the windows using %otherwin,
but instead of spilling user window directly to the pcb, we attempt to
spill to user space.  If this fails because a stack page is not resident
(or the stack is smashed), the fault handler at tl 2 will detect the
situation and resume at tl 1 again where recovery code can spill to the
pcb.  Any windows that have been saved to the pcb will be copied out to
the user stack on return from kernel mode.

Add a first stab at 32 bit window handling.  This uses much of the same
recovery code as above because the alignment of the stack pointer is used
to detect 32 bit code.  Attempting to spill a 32 bit window to a 64 bit
stack, or vice versa, will cause an alignment fault.  The recovery code
then changes the window state to vector to a 32 bit spill/fill handler
and retries the faulting instruction.

Add ktr traces in useful places during trap processing.

Adjust comments to reflect new code and add many more.

1 files changed, 100 insertions, 0 deletions

diff --git a/sys/sparc64/sparc64/rwindow.c b/sys/sparc64/sparc64/rwindow.c
new file mode 100644
index 0000000..474e6a9
--- /dev/null
+++ b/sys/sparc64/sparc64/rwindow.c
@@ -0,0 +1,100 @@
+/*-
+ * Copyright (c) 1997 Berkeley Software Design, Inc. 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. Berkeley Software Design Inc's name may not be used to endorse or
+ *    promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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.
+ *
+ *	from: BSDI: trap.c,v 1.17.2.9 1999/10/19 15:29:52 cp Exp
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/ktr.h>
+#include <sys/proc.h>
+#include <sys/user.h>
+
+#include <machine/frame.h>
+
+int
+rwindow_load(struct proc *p, struct trapframe *tf, int n)
+{
+	struct rwindow rw;
+	u_long usp;
+	int error;
+	int i;
+
+	/*
+	 * In case current window is still only on-chip, push it out;
+	 * if it cannot get all the way out, we cannot continue either.
+	 */
+	if ((error = rwindow_save(p)) != 0)
+		return (error);
+	usp = tf->tf_out[6];
+	CTR3(KTR_TRAP, "rwindow_load: p=%p (%s) n=%d",
+	    p, p->p_comm, n);
+	for (i = 0; i < n; i++) {
+		CTR1(KTR_TRAP, "rwindow_load: usp=%#lx", usp);
+		usp += SPOFF;
+		error = copyin((void *)usp, &rw, sizeof rw);
+		usp = rw.rw_in[6];
+	}
+	CTR1(KTR_TRAP, "rwindow_load: error=%d", error);
+	return (error);
+}
+
+int
+rwindow_save(struct proc *p)
+{
+	struct rwindow *rw;
+	struct pcb *pcb;
+	u_long *ausp;
+	u_long usp;
+	int error;
+	int i;
+
+	flushw();
+	pcb = &p->p_addr->u_pcb;
+	i = pcb->pcb_nsaved;
+	CTR3(KTR_TRAP, "rwindow_save: p=%p (%s) nsaved=%d", p, p->p_comm, i);
+	if (i == 0)
+		return (0);
+	ausp = pcb->pcb_rwsp;
+	rw = pcb->pcb_rw;
+	error = 0;
+	do {
+		usp = *ausp;
+		CTR1(KTR_TRAP, "rwindow_save: usp=%#lx", usp);
+		usp += SPOFF;
+		error = copyout(rw, (void *)usp, sizeof *rw);
+		if (error)
+			break;
+		ausp++;
+		rw++;
+	} while (--i > 0);
+	CTR1(KTR_TRAP, "rwindow_save: error=%d", error);
+	if (error == 0)
+		pcb->pcb_nsaved = 0;
+	return (error);
+}