xref: /freebsd/sys/amd64/amd64/gdb_machdep.c (revision 6137b5f7b8c183ee8806d79b3f1d8e5e3ddb3df3)
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/cpufunc.h>
38 #include <machine/frame.h>
39 #include <machine/gdb_machdep.h>
40 #include <machine/md_var.h>
41 #include <machine/pcb.h>
42 #include <machine/psl.h>
43 #include <machine/specialreg.h>
44 #include <machine/trap.h>
45 #include <machine/frame.h>
46 #include <machine/endian.h>
47 
48 #include <gdb/gdb.h>
49 #include <gdb/gdb_int.h>
50 
51 void *
52 gdb_cpu_getreg(int regnum, size_t *regsz)
53 {
54 	static uint32_t _kcodesel = GSEL(GCODE_SEL, SEL_KPL);
55 	static uint32_t _kdatasel = GSEL(GDATA_SEL, SEL_KPL);
56 
57 	*regsz = gdb_cpu_regsz(regnum);
58 
59 	if (kdb_thread  == curthread) {
60 		switch (regnum) {
61 		case GDB_REG_RAX: return (&kdb_frame->tf_rax);
62 		case GDB_REG_RCX: return (&kdb_frame->tf_rcx);
63 		case GDB_REG_RDX: return (&kdb_frame->tf_rdx);
64 		case GDB_REG_RSI: return (&kdb_frame->tf_rsi);
65 		case GDB_REG_RDI: return (&kdb_frame->tf_rdi);
66 		case GDB_REG_R8:  return (&kdb_frame->tf_r8);
67 		case GDB_REG_R9:  return (&kdb_frame->tf_r9);
68 		case GDB_REG_R10: return (&kdb_frame->tf_r10);
69 		case GDB_REG_R11: return (&kdb_frame->tf_r11);
70 		case GDB_REG_RFLAGS: return (&kdb_frame->tf_rflags);
71 		case GDB_REG_CS:  return (&kdb_frame->tf_cs);
72 		case GDB_REG_SS:  return (&kdb_frame->tf_ss);
73 		}
74 	}
75 	switch (regnum) {
76 	case GDB_REG_RBX: return (&kdb_thrctx->pcb_rbx);
77 	case GDB_REG_RBP: return (&kdb_thrctx->pcb_rbp);
78 	case GDB_REG_RSP: return (&kdb_thrctx->pcb_rsp);
79 	case GDB_REG_R12: return (&kdb_thrctx->pcb_r12);
80 	case GDB_REG_R13: return (&kdb_thrctx->pcb_r13);
81 	case GDB_REG_R14: return (&kdb_thrctx->pcb_r14);
82 	case GDB_REG_R15: return (&kdb_thrctx->pcb_r15);
83 	case GDB_REG_PC:  return (&kdb_thrctx->pcb_rip);
84 	case GDB_REG_CS:  return (&_kcodesel);
85 	case GDB_REG_SS:  return (&_kdatasel);
86 	}
87 	return (NULL);
88 }
89 
90 void
91 gdb_cpu_setreg(int regnum, void *val)
92 {
93 	register_t regval = *(register_t *)val;
94 
95 	/*
96 	 * Write registers to the trapframe and pcb, if applicable.
97 	 * Some scratch registers are not tracked by the pcb.
98 	 */
99 	if (kdb_thread == curthread) {
100 		switch (regnum) {
101 		case GDB_REG_RAX: kdb_frame->tf_rax = regval; break;
102 		case GDB_REG_RBX: kdb_frame->tf_rbx = regval; break;
103 		case GDB_REG_RCX: kdb_frame->tf_rcx = regval; break;
104 		case GDB_REG_RDX: kdb_frame->tf_rdx = regval; break;
105 		case GDB_REG_RSI: kdb_frame->tf_rsi = regval; break;
106 		case GDB_REG_RDI: kdb_frame->tf_rdi = regval; break;
107 		case GDB_REG_RBP: kdb_frame->tf_rbp = regval; break;
108 		case GDB_REG_RSP: kdb_frame->tf_rsp = regval; break;
109 		case GDB_REG_R8:  kdb_frame->tf_r8  = regval; break;
110 		case GDB_REG_R9:  kdb_frame->tf_r9  = regval; break;
111 		case GDB_REG_R10: kdb_frame->tf_r10 = regval; break;
112 		case GDB_REG_R11: kdb_frame->tf_r11 = regval; break;
113 		case GDB_REG_R12: kdb_frame->tf_r12 = regval; break;
114 		case GDB_REG_R13: kdb_frame->tf_r13 = regval; break;
115 		case GDB_REG_R14: kdb_frame->tf_r14 = regval; break;
116 		case GDB_REG_R15: kdb_frame->tf_r15 = regval; break;
117 		case GDB_REG_PC:  kdb_frame->tf_rip = regval; break;
118 		}
119 	}
120 	switch (regnum) {
121 	case GDB_REG_RBX: kdb_thrctx->pcb_rbx = regval; break;
122 	case GDB_REG_RBP: kdb_thrctx->pcb_rbp = regval; break;
123 	case GDB_REG_RSP: kdb_thrctx->pcb_rsp = regval; break;
124 	case GDB_REG_R12: kdb_thrctx->pcb_r12 = regval; break;
125 	case GDB_REG_R13: kdb_thrctx->pcb_r13 = regval; break;
126 	case GDB_REG_R14: kdb_thrctx->pcb_r14 = regval; break;
127 	case GDB_REG_R15: kdb_thrctx->pcb_r15 = regval; break;
128 	case GDB_REG_PC:  kdb_thrctx->pcb_rip = regval; break;
129 	}
130 }
131 
132 int
133 gdb_cpu_signal(int type, int code)
134 {
135 
136 	switch (type) {
137 	case T_BPTFLT: return (SIGTRAP);
138 	case T_ARITHTRAP: return (SIGFPE);
139 	case T_PROTFLT: return (SIGSEGV);
140 	case T_TRCTRAP: return (SIGTRAP);
141 	case T_PAGEFLT: return (SIGSEGV);
142 	case T_DIVIDE: return (SIGFPE);
143 	case T_NMI: return (SIGTRAP);
144 	case T_FPOPFLT: return (SIGILL);
145 	case T_TSSFLT: return (SIGSEGV);
146 	case T_SEGNPFLT: return (SIGSEGV);
147 	case T_STKFLT: return (SIGSEGV);
148 	case T_XMMFLT: return (SIGFPE);
149 	}
150 	return (SIGEMT);
151 }
152 
153 void
154 gdb_cpu_stop_reason(int type, int code)
155 {
156 	uintmax_t val;
157 
158 	val = 0;
159 	if (type == T_TRCTRAP) {
160 		/* NB: 'code' contains the value of dr6 at the trap. */
161 		if ((code & DBREG_DR6_B(0)) != 0) {
162 			val = rdr0();
163 		}
164 		if ((code & DBREG_DR6_B(1)) != 0) {
165 			val = rdr1();
166 		}
167 		if ((code & DBREG_DR6_B(2)) != 0) {
168 			val = rdr2();
169 		}
170 		if ((code & DBREG_DR6_B(3)) != 0) {
171 			val = rdr3();
172 		}
173 
174 		/*
175 		 * TODO: validate the bits in DR7 to differentiate between a
176 		 * watchpoint trap and a hardware breakpoint trap (currently
177 		 * unsupported).
178 		 */
179 		if (val != 0) {
180 			gdb_tx_str("watch:");
181 			gdb_tx_varhex(val);
182 			gdb_tx_char(';');
183 		}
184 	}
185 }
186 
187 void *
188 gdb_begin_write(void)
189 {
190 
191 	return (disable_wp() ? &gdb_begin_write : NULL);
192 }
193 
194 void
195 gdb_end_write(void *arg)
196 {
197 
198 	restore_wp(arg != NULL);
199 }
200