1 /* $NetBSD: kgdb_glue.c,v 1.10 2007/10/17 19:58:04 garbled 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 1.10 2007/10/17 19:58:04 garbled Exp $");
49
50 #include "opt_kgdb.h"
51
52 #ifdef KGDB
53
54 #include <sys/param.h>
55
56 #include <machine/frame.h>
57 #include <machine/reg.h>
58
59 #ifndef lint
60 static char rcsid[] = "$NetBSD: kgdb_glue.c,v 1.10 2007/10/17 19:58:04 garbled Exp $";
61 #endif
62
63 #define KGDB_STACKSIZE 0x800
64 #define KGDB_STACKWORDS (KGDB_STACKSIZE / sizeof(u_long))
65
66 u_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
71 static inline void
copywords(u_long * src,u_long * dst,u_int nbytes)72 copywords(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
83 int
kgdb_trap_glue(int type,struct frame frame)84 kgdb_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
143 int kgdb_testval;
144
145 int
kgdb_test(int i)146 kgdb_test(int i)
147 {
148 ++kgdb_testval;
149 return (i + 1);
150 }
151 #endif /* KGDB */
152