1 /* $NetBSD: db_interface.c,v 1.36 2022/10/26 23:38:08 riastradh Exp $ */
2
3 /*
4 * Mach Operating System
5 * Copyright (c) 1992 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
15 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
21 * School of Computer Science
22 * Carnegie Mellon University
23 * Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie Mellon
26 * the rights to redistribute these changes.
27 */
28
29 /*
30 * Interface to the "ddb" kernel debugger.
31 */
32
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.36 2022/10/26 23:38:08 riastradh Exp $");
35
36 #include <sys/param.h>
37 #include <sys/proc.h>
38 #include <sys/reboot.h>
39 #include <sys/systm.h> /* just for boothowto --eichin */
40
41 #include <uvm/uvm_extern.h>
42
43 #include <dev/cons.h>
44
45 #include <machine/trap.h>
46 #include <machine/db_machdep.h>
47
48 #include <ddb/db_active.h>
49 #include <ddb/db_command.h>
50 #include <ddb/db_sym.h>
51 #ifdef _KERNEL
52 #include <ddb/db_extern.h>
53 #endif
54
55 int db_active = 0;
56 db_regs_t ddb_regs;
57
58 #ifdef _KERNEL
59 static void kdbprinttrap(int, int);
60
61 /*
62 * Received keyboard interrupt sequence.
63 */
64 void
kdb_kintr(db_regs_t * regs)65 kdb_kintr(db_regs_t *regs)
66 {
67
68 if (db_active == 0 && (boothowto & RB_KDB)) {
69 printf("\n\nkernel: keyboard interrupt\n");
70 kdb_trap(-1, regs);
71 }
72 }
73
74 /*
75 * kdb_trap - field a TRACE or BPT trap
76 * Return non-zero if we "handled" the trap.
77 */
78 int
kdb_trap(int type,db_regs_t * regs)79 kdb_trap(int type, db_regs_t *regs)
80 {
81
82 switch (type) {
83 case T_TRACE: /* single-step */
84 case T_BREAKPOINT: /* breakpoint */
85 /* case T_WATCHPOINT:*/
86 break;
87 case -1:
88 break;
89 default:
90 kdbprinttrap(type, 0);
91 if (db_recover != 0) {
92 /* This will longjmp back to db_command_loop */
93 db_error("Caught exception in ddb.\n");
94 /*NOTREACHED*/
95 }
96 /*
97 * Tell caller "We did NOT handle the trap."
98 * Caller should panic or whatever.
99 */
100 return 0;
101 }
102
103 /*
104 * We'd like to be on a separate debug stack here, but
105 * that's easier to do in locore.s before we get here.
106 * See sun3/locore.s:T_TRACE for stack switch code.
107 */
108
109 ddb_regs = *regs;
110
111 db_active++;
112 cnpollc(true); /* set polling mode, unblank video */
113
114 db_trap(type, 0); /* where the work happens */
115
116 cnpollc(false); /* resume interrupt mode */
117 db_active--;
118
119 *regs = ddb_regs;
120
121 /*
122 * Indicate that single_step is for KDB.
123 * But lock out interrupts to prevent TRACE_KDB from setting the
124 * trace bit in the current SR (and trapping while exiting KDB).
125 */
126 (void)spl7();
127
128 /*
129 * Tell caller "We HAVE handled the trap."
130 * Caller will return to locore and rte.
131 */
132 return 1;
133 }
134
135 extern char *trap_type[];
136 extern int trap_types;
137
138 /*
139 * Print trap reason.
140 */
141 static void
kdbprinttrap(int type,int code)142 kdbprinttrap(int type, int code)
143 {
144
145 printf("kernel: ");
146 if (type >= trap_types || type < 0)
147 printf("type %d", type);
148 else
149 printf("%s", trap_type[type]);
150 printf(" trap\n");
151 }
152
153 void
cpu_Debugger(void)154 cpu_Debugger(void)
155 {
156
157 __asm ("trap #15");
158 }
159 #endif
160