1 /* $NetBSD: kgdb_machdep.c,v 1.6 2022/08/22 13:57:24 hannken Exp $ */
2
3 /*
4 * Copyright (c) 1997, 2017 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 /*
34 * Copyright (c) 1996 Matthias Pfaller.
35 * All rights reserved.
36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 * notice, this list of conditions and the following disclaimer.
42 * 2. Redistributions in binary form must reproduce the above copyright
43 * notice, this list of conditions and the following disclaimer in the
44 * documentation and/or other materials provided with the distribution.
45 *
46 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
47 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
48 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
49 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
50 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
51 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
52 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
53 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
54 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
55 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56 */
57
58 #include <sys/cdefs.h>
59 __KERNEL_RCSID(0, "$NetBSD: kgdb_machdep.c,v 1.6 2022/08/22 13:57:24 hannken Exp $");
60
61 #include "opt_ddb.h"
62
63 /*
64 * Machine-dependent functions for remote KGDB. Originally written
65 * for NetBSD/pc532 by Matthias Pfaller. Modified for NetBSD/i386
66 * by Jason R. Thorpe. Modified for NetBSD/amd64 by Frank van der Linden.
67 */
68
69 #include <sys/param.h>
70 #include <sys/kgdb.h>
71 #include <sys/systm.h>
72
73 #include <machine/pmap_private.h>
74 #include <machine/pte.h>
75 #include <machine/trap.h>
76
77 /*
78 * Determine if the memory at va..(va+len) is valid.
79 */
80 int
kgdb_acc(vaddr_t va,size_t len)81 kgdb_acc(vaddr_t va, size_t len)
82 {
83 vaddr_t last_va;
84 pt_entry_t *pte;
85
86 last_va = va + len;
87 va &= ~PGOFSET;
88 last_va &= ~PGOFSET;
89
90 do {
91 if (va < VM_MIN_KERNEL_ADDRESS)
92 pte = vtopte(va);
93 else
94 pte = kvtopte(va);
95 if ((*pte & PTE_P) == 0)
96 return 0;
97 if (*pte & PTE_PS)
98 va = (va & PTE_LGFRAME) + NBPD_L2;
99 else
100 va += PAGE_SIZE;
101 } while (va < last_va);
102
103 return 1;
104 }
105
106 void
kgdb_entry_notice(int type,db_regs_t * regs)107 kgdb_entry_notice(int type, db_regs_t *regs)
108 {
109 if (type == T_NMI)
110 printf("NMI ... going to debugger\n");
111 }
112
113 /*
114 * Translate a trap number into a unix compatible signal value.
115 * (gdb only understands unix signal numbers).
116 */
117 int
kgdb_signal(int type)118 kgdb_signal(int type)
119 {
120 switch (type) {
121 case T_NMI:
122 return SIGINT;
123
124 case T_ALIGNFLT:
125 return SIGILL;
126
127 case T_BPTFLT:
128 case T_TRCTRAP:
129 return SIGTRAP;
130
131 case T_ASTFLT:
132 case T_DOUBLEFLT:
133 return SIGEMT;
134
135 case T_ARITHTRAP:
136 case T_DIVIDE:
137 case T_OFLOW:
138 case T_DNA:
139 case T_FPOPFLT:
140 return SIGFPE;
141
142 case T_PRIVINFLT:
143 case T_PROTFLT:
144 case T_PAGEFLT:
145 case T_TSSFLT:
146 case T_SEGNPFLT:
147 case T_STKFLT:
148 return SIGSEGV;
149
150 case T_BOUND:
151 return SIGURG;
152
153 default:
154 return SIGEMT;
155 }
156 }
157
158 /*
159 * Translate the values stored in the kernel regs struct to the format
160 * understood by gdb.
161 */
162 void
kgdb_getregs(db_regs_t * regs,kgdb_reg_t * gdb_regs)163 kgdb_getregs(db_regs_t *regs, kgdb_reg_t *gdb_regs)
164 {
165 #ifdef __x86_64__
166 gdb_regs[ 0] = regs->tf_rax;
167 gdb_regs[ 1] = regs->tf_rbx;
168 gdb_regs[ 2] = regs->tf_rcx;
169 gdb_regs[ 3] = regs->tf_rdx;
170 gdb_regs[ 4] = regs->tf_rsi;
171 gdb_regs[ 5] = regs->tf_rdi;
172 gdb_regs[ 6] = regs->tf_rbp;
173 gdb_regs[ 7] = regs->tf_rsp;
174 gdb_regs[ 8] = regs->tf_r8;
175 gdb_regs[ 9] = regs->tf_r9;
176 gdb_regs[10] = regs->tf_r10;
177 gdb_regs[11] = regs->tf_r11;
178 gdb_regs[12] = regs->tf_r12;
179 gdb_regs[13] = regs->tf_r13;
180 gdb_regs[14] = regs->tf_r14;
181 gdb_regs[15] = regs->tf_r15;
182 gdb_regs[16] = regs->tf_rip;
183 gdb_regs[17] = regs->tf_rflags;
184 gdb_regs[18] = regs->tf_cs;
185 gdb_regs[19] = regs->tf_ss;
186 #else
187 gdb_regs[ 0] = regs->tf_eax;
188 gdb_regs[ 1] = regs->tf_ecx;
189 gdb_regs[ 2] = regs->tf_edx;
190 gdb_regs[ 3] = regs->tf_ebx;
191 gdb_regs[ 5] = regs->tf_ebp;
192 gdb_regs[ 6] = regs->tf_esi;
193 gdb_regs[ 7] = regs->tf_edi;
194 gdb_regs[ 8] = regs->tf_eip;
195 gdb_regs[ 9] = regs->tf_eflags;
196 gdb_regs[10] = regs->tf_cs;
197 gdb_regs[12] = regs->tf_ds;
198 gdb_regs[13] = regs->tf_es;
199 gdb_regs[14] = regs->tf_fs;
200 gdb_regs[15] = regs->tf_gs;
201
202 if (KERNELMODE(regs->tf_cs)) {
203 /*
204 * Kernel mode - esp and ss not saved.
205 */
206 gdb_regs[ 4] = (kgdb_reg_t)®s->tf_esp; /* kernel stack
207 pointer */
208 gdb_regs[11] = x86_getss();
209 }
210 #endif
211 }
212
213 /*
214 * Reverse the above.
215 */
216 void
kgdb_setregs(db_regs_t * regs,kgdb_reg_t * gdb_regs)217 kgdb_setregs(db_regs_t *regs, kgdb_reg_t *gdb_regs)
218 {
219 #ifdef __x86_64__
220 regs->tf_rax = gdb_regs[ 0];
221 regs->tf_rbx = gdb_regs[ 1];
222 regs->tf_rcx = gdb_regs[ 2];
223 regs->tf_rdx = gdb_regs[ 3];
224 regs->tf_rsi = gdb_regs[ 4];
225 regs->tf_rdi = gdb_regs[ 5];
226 regs->tf_rbp = gdb_regs[ 6];
227 regs->tf_rsp = gdb_regs[ 7];
228 regs->tf_r8 = gdb_regs[ 8];
229 regs->tf_r9 = gdb_regs[ 9];
230 regs->tf_r10 = gdb_regs[10];
231 regs->tf_r11 = gdb_regs[11];
232 regs->tf_r12 = gdb_regs[12];
233 regs->tf_r13 = gdb_regs[13];
234 regs->tf_r14 = gdb_regs[14];
235 regs->tf_r15 = gdb_regs[15];
236 regs->tf_rip = gdb_regs[16];
237 regs->tf_rflags = gdb_regs[17];
238 regs->tf_cs = gdb_regs[18];
239 regs->tf_ss = gdb_regs[19];
240 #else
241 regs->tf_eax = gdb_regs[ 0];
242 regs->tf_ecx = gdb_regs[ 1];
243 regs->tf_edx = gdb_regs[ 2];
244 regs->tf_ebx = gdb_regs[ 3];
245 regs->tf_ebp = gdb_regs[ 5];
246 regs->tf_esi = gdb_regs[ 6];
247 regs->tf_edi = gdb_regs[ 7];
248 regs->tf_eip = gdb_regs[ 8];
249 regs->tf_eflags = gdb_regs[ 9];
250 regs->tf_cs = gdb_regs[10];
251 regs->tf_ds = gdb_regs[12];
252 regs->tf_es = gdb_regs[13];
253
254 if (KERNELMODE(regs->tf_cs) == 0) {
255 /*
256 * Trapped in user mode - restore esp and ss.
257 */
258 regs->tf_esp = gdb_regs[ 4];
259 regs->tf_ss = gdb_regs[11];
260 }
261 #endif
262 }
263
264 /*
265 * Trap into kgdb to wait for debugger to connect,
266 * noting on the console why nothing else is going on.
267 */
268 void
kgdb_connect(int verbose)269 kgdb_connect(int verbose)
270 {
271 if (kgdb_dev == NODEV)
272 return;
273
274 if (verbose)
275 printf("kgdb waiting...");
276
277 breakpoint();
278
279 if (verbose)
280 printf("connected.\n");
281
282 kgdb_debug_panic = 1;
283 }
284
285 /*
286 * Decide what to do on panic.
287 * (This is called by panic, like Debugger())
288 */
289 void
kgdb_panic(void)290 kgdb_panic(void)
291 {
292 if (kgdb_dev != NODEV && kgdb_debug_panic) {
293 printf("entering kgdb\n");
294 kgdb_connect(kgdb_active == 0);
295 }
296 }
297