xref: /freebsd/sys/i386/i386/gdb_machdep.c (revision e0c4386e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2004 Marcel Moolenaar
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kdb.h>
32 #include <sys/kernel.h>
33 #include <sys/proc.h>
34 #include <sys/reg.h>
35 #include <sys/signal.h>
36 
37 #include <machine/endian.h>
38 #include <machine/frame.h>
39 #include <machine/gdb_machdep.h>
40 #include <machine/pcb.h>
41 #include <machine/trap.h>
42 
43 #include <gdb/gdb.h>
44 #include <gdb/gdb_int.h>
45 
46 void *
47 gdb_cpu_getreg(int regnum, size_t *regsz)
48 {
49 	static uint32_t _kcodesel = GSEL(GCODE_SEL, SEL_KPL);
50 	static uint32_t _kdatasel = GSEL(GDATA_SEL, SEL_KPL);
51 	static uint32_t _kprivsel = GSEL(GPRIV_SEL, SEL_KPL);
52 
53 	*regsz = gdb_cpu_regsz(regnum);
54 
55 	if (kdb_thread == curthread) {
56 		switch (regnum) {
57 		case 0:	return (&kdb_frame->tf_eax);
58 		case 1:	return (&kdb_frame->tf_ecx);
59 		case 2:	return (&kdb_frame->tf_edx);
60 		case 9: return (&kdb_frame->tf_eflags);
61 		case 10: return (&kdb_frame->tf_cs);
62 		case 12: return (&kdb_frame->tf_ds);
63 		case 13: return (&kdb_frame->tf_es);
64 		case 14: return (&kdb_frame->tf_fs);
65 		}
66 	}
67 	switch (regnum) {
68 	case 3:  return (&kdb_thrctx->pcb_ebx);
69 	case 4:  return (&kdb_thrctx->pcb_esp);
70 	case 5:  return (&kdb_thrctx->pcb_ebp);
71 	case 6:  return (&kdb_thrctx->pcb_esi);
72 	case 7:  return (&kdb_thrctx->pcb_edi);
73 	case 8:  return (&kdb_thrctx->pcb_eip);
74 	case 10: return (&_kcodesel);
75 	case 11: return (&_kdatasel);
76 	case 12: return (&_kdatasel);
77 	case 13: return (&_kdatasel);
78 	case 14: return (&_kprivsel);
79 	case 15: return (&kdb_thrctx->pcb_gs);
80 	}
81 	return (NULL);
82 }
83 
84 void
85 gdb_cpu_setreg(int regnum, void *val)
86 {
87 
88 	switch (regnum) {
89 	case GDB_REG_PC:
90 		kdb_thrctx->pcb_eip = *(register_t *)val;
91 		if (kdb_thread  == curthread)
92 			kdb_frame->tf_eip = *(register_t *)val;
93 	}
94 }
95 
96 int
97 gdb_cpu_signal(int type, int code)
98 {
99 
100 	switch (type) {
101 	case T_BPTFLT: return (SIGTRAP);
102 	case T_ARITHTRAP: return (SIGFPE);
103 	case T_PROTFLT: return (SIGSEGV);
104 	case T_TRCTRAP: return (SIGTRAP);
105 	case T_PAGEFLT: return (SIGSEGV);
106 	case T_DIVIDE: return (SIGFPE);
107 	case T_NMI: return (SIGTRAP);
108 	case T_FPOPFLT: return (SIGILL);
109 	case T_TSSFLT: return (SIGSEGV);
110 	case T_SEGNPFLT: return (SIGSEGV);
111 	case T_STKFLT: return (SIGSEGV);
112 	case T_XMMFLT: return (SIGFPE);
113 	}
114 	return (SIGEMT);
115 }
116 
117 void
118 gdb_cpu_stop_reason(int type, int code)
119 {
120 	uintmax_t val;
121 
122 	val = 0;
123 	if (type == T_TRCTRAP) {
124 		/* NB: 'code' contains the value of dr6 at the trap. */
125 		if ((code & DBREG_DR6_B(0)) != 0) {
126 			val = rdr0();
127 		}
128 		if ((code & DBREG_DR6_B(1)) != 0) {
129 			val = rdr1();
130 		}
131 		if ((code & DBREG_DR6_B(2)) != 0) {
132 			val = rdr2();
133 		}
134 		if ((code & DBREG_DR6_B(3)) != 0) {
135 			val = rdr3();
136 		}
137 
138 		/*
139 		 * TODO: validate the bits in DR7 to differentiate between a
140 		 * watchpoint trap and a hardware breakpoint trap (currently
141 		 * unsupported).
142 		 */
143 		if (val != 0) {
144 			gdb_tx_str("watch:");
145 			gdb_tx_varhex(val);
146 			gdb_tx_char(';');
147 		}
148 	}
149 }
150