1/*	$NetBSD: kgdb_glue.c,v 1.8.38.1 2007/05/22 17:27:47 matt Exp $	*/
2
3/*
4 * Copyright (c) 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
10 *
11 * All advertising materials mentioning features or use of this software
12 * must display the following acknowledgement:
13 *	This product includes software developed by the University of
14 *	California, Lawrence Berkeley Laboratories.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 *    notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 *    notice, this list of conditions and the following disclaimer in the
23 *    documentation and/or other materials provided with the distribution.
24 * 3. Neither the name of the University nor the names of its contributors
25 *    may be used to endorse or promote products derived from this software
26 *    without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 *	@(#)kgdb_glue.c	8.2 (Berkeley) 1/12/94
41 */
42
43/*
44 * This file must be compiled with gcc -fno-defer-pop.
45 */
46
47#include <sys/cdefs.h>
48__KERNEL_RCSID(0, "$NetBSD: kgdb_glue.c,v 1.8.38.1 2007/05/22 17:27:47 matt Exp $");
49
50#include "opt_kgdb.h"
51
52#ifdef KGDB
53
54#include <sys/param.h>
55
56#include <machine/frame.h>
57#include <machine/reg.h>
58
59#ifndef lint
60static char rcsid[] = "$NetBSD: kgdb_glue.c,v 1.8.38.1 2007/05/22 17:27:47 matt Exp $";
61#endif
62
63#define KGDB_STACKSIZE 0x800
64#define KGDB_STACKWORDS (KGDB_STACKSIZE / sizeof(u_long))
65
66u_long kgdb_stack[KGDB_STACKWORDS];
67
68#define getsp(v) __asm("movl %%sp, %0" : "=r" (v))
69#define setsp(v) __asm("movl %0, %%sp" :: "r" (v))
70
71static inline void
72copywords(u_long *src, u_long *dst, u_int nbytes)
73{
74	u_long *limit = src + (nbytes / sizeof(u_long));
75
76	do {
77		*dst++ = *src++;
78	} while (src < limit);
79	if (nbytes & 2)
80		*(u_short *)dst = *(u_short *)src;
81}
82
83int
84kgdb_trap_glue(int type, struct frame frame)
85{
86	u_long osp, nsp;
87	u_int fsize, s;
88	extern short exframesize[];
89
90	/*
91	 * After a kernel mode trap, the saved sp doesn't point to the right
92	 * place.  The correct value is the top of the frame (i.e. before the
93	 * KGDB trap).
94	 *
95	 * XXX this may have to change if we implement an interrupt stack.
96	 */
97	fsize = sizeof(frame) - sizeof(frame.F_u) + exframesize[frame.f_format];
98	frame.f_regs[SP] = (u_long)&frame + fsize;
99
100	/*
101	 * Copy the interrupt context and frame to the new stack.
102	 * We're throwing away trap()'s frame since we're going to do
103	 * our own rte.
104	 */
105	nsp = (u_long)&kgdb_stack[KGDB_STACKWORDS] -
106	      roundup(fsize, sizeof(u_long));
107
108	copywords((u_long *)&frame, (u_long *)nsp, fsize);
109
110	s = splhigh();
111
112	getsp(osp);
113	setsp(nsp);
114
115	if (kgdb_trap(type, (struct frame *)nsp) == 0) {
116		/*
117		 * Get back on kernel stack.  This thread of control
118		 * will return back up through trap().  If kgdb_trap()
119		 * returns 0, it didn't handle the trap at all so
120		 * the stack is still intact and everything will
121		 * unwind okay from here up.
122		 */
123		setsp(osp);
124		splx(s);
125		return 0;
126	}
127	/*
128	 * Copy back context, which has possibly changed.  Even the
129	 * sp might have changed.
130	 */
131	osp = ((struct frame *)nsp)->f_regs[SP] - fsize;
132	copywords((u_long *)nsp, (u_long *)osp, fsize);
133	setsp(osp);
134
135	/*
136	 * Restore the possible new context from frame, pop the
137	 * unneeded usp (we trapped from kernel mode) and pad word,
138	 * and return to the trapped thread.
139	 */
140	__asm("moveml %sp@+,#0x7FFF; addql #8,sp; rte");
141}
142
143int kgdb_testval;
144
145int
146kgdb_test(int i)
147{
148	++kgdb_testval;
149	return (i + 1);
150}
151#endif /* KGDB */
152