1 /*
2 * Copyright (c) 2008 The DragonFly Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 * 3. Neither the name of The DragonFly Project nor the names of its
15 * contributors may be used to endorse or promote products derived
16 * from this software without specific, prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
28 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * --
32 *
33 * Mach Operating System
34 * Copyright (c) 1991,1990 Carnegie Mellon University
35 * All Rights Reserved.
36 *
37 * Permission to use, copy, modify and distribute this software and its
38 * documentation is hereby granted, provided that both the copyright
39 * notice and this permission notice appear in all copies of the
40 * software, derivative works or modified versions, and any portions
41 * thereof, and that both notices appear in supporting documentation.
42 *
43 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
44 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
45 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
46 *
47 * Carnegie Mellon requests users of this software to return to
48 *
49 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
50 * School of Computer Science
51 * Carnegie Mellon University
52 * Pittsburgh PA 15213-3890
53 *
54 * any improvements or extensions that they make and grant Carnegie the
55 * rights to redistribute these changes.
56 *
57 * $FreeBSD: src/sys/i386/i386/db_interface.c,v 1.48.2.1 2000/07/07 00:38:46 obrien Exp $
58 */
59
60 /*
61 * Interface to new debugger.
62 */
63 #include <sys/param.h>
64 #include <sys/systm.h>
65 #include <sys/reboot.h>
66 #include <sys/cons.h>
67 #include <sys/thread.h>
68 #include <sys/kerneldump.h>
69
70 #include <machine/cpu.h>
71 #include <machine/smp.h>
72 #include <machine/globaldata.h>
73 #include <machine/md_var.h>
74
75 #include <vm/vm.h>
76 #include <vm/pmap.h>
77
78 #include <ddb/ddb.h>
79
80 #include <sys/thread2.h>
81
82 #include <machine/setjmp.h>
83
84 static jmp_buf *db_nofault = NULL;
85 extern jmp_buf db_jmpbuf;
86
87 extern void gdb_handle_exception (db_regs_t *, int, int);
88
89 int db_active;
90 db_regs_t ddb_regs;
91
92 static jmp_buf db_global_jmpbuf;
93 static int db_global_jmpbuf_valid;
94
95 #ifdef __GNUC__
96 #define rss() ({u_short ss; __asm __volatile("mov %%ss,%0" : "=r" (ss)); ss;})
97 #endif
98
99 /*
100 * kdb_trap - field a TRACE or BPT trap
101 */
102 int
kdb_trap(int type,int code,struct x86_64_saved_state * regs)103 kdb_trap(int type, int code, struct x86_64_saved_state *regs)
104 {
105 volatile int ddb_mode = !(boothowto & RB_GDB);
106
107 /*
108 * XXX try to do nothing if the console is in graphics mode.
109 * Handle trace traps (and hardware breakpoints...) by ignoring
110 * them except for forgetting about them. Return 0 for other
111 * traps to say that we haven't done anything. The trap handler
112 * will usually panic. We should handle breakpoint traps for
113 * our breakpoints by disarming our breakpoints and fixing up
114 * %eip.
115 */
116 if (cons_unavail && ddb_mode) {
117 if (type == T_TRCTRAP) {
118 regs->tf_rflags &= ~PSL_T;
119 return (1);
120 }
121 return (0);
122 }
123
124 switch (type) {
125 case T_BPTFLT: /* breakpoint */
126 case T_TRCTRAP: /* debug exception */
127 break;
128
129 default:
130 /*
131 * XXX this is almost useless now. In most cases,
132 * trap_fatal() has already printed a much more verbose
133 * message. However, it is dangerous to print things in
134 * trap_fatal() - kprintf() might be reentered and trap.
135 * The debugger should be given control first.
136 */
137 if (ddb_mode)
138 db_printf("kernel: type %d trap, code=%x\n", type, code);
139
140 if (db_nofault) {
141 jmp_buf *no_fault = db_nofault;
142 db_nofault = NULL;
143 longjmp(*no_fault, 1);
144 }
145 }
146
147 /*
148 * This handles unexpected traps in ddb commands, including calls to
149 * non-ddb functions. db_nofault only applies to memory accesses by
150 * internal ddb commands.
151 */
152 if (db_global_jmpbuf_valid)
153 longjmp(db_global_jmpbuf, 1);
154
155 /*
156 * XXX We really should switch to a local stack here.
157 */
158 ddb_regs = *regs;
159
160 crit_enter();
161 db_printf("\nCPU%d stopping CPUs: 0x%08jx\n",
162 mycpu->gd_cpuid,
163 (uintmax_t)CPUMASK_LOWMASK(mycpu->gd_other_cpus));
164
165 /* We stop all CPUs except ourselves (obviously) */
166 stop_cpus(mycpu->gd_other_cpus);
167
168 db_printf(" stopped\n");
169
170 setjmp(db_global_jmpbuf);
171 db_global_jmpbuf_valid = TRUE;
172 db_active++;
173 /* vcons_set_mode(1); */
174 if (ddb_mode) {
175 cndbctl(TRUE);
176 db_trap(type, code);
177 cndbctl(FALSE);
178 } else
179 gdb_handle_exception(&ddb_regs, type, code);
180 db_active--;
181 /* vcons_set_mode(0); */
182 db_global_jmpbuf_valid = FALSE;
183
184 if (panicstr == NULL) {
185 db_printf("\nCPU%d restarting CPUs: 0x%016jx\n",
186 mycpu->gd_cpuid,
187 (uintmax_t)CPUMASK_LOWMASK(stopped_cpus));
188
189 /* Restart all the CPUs we previously stopped */
190 if (CPUMASK_CMPMASKNEQ(stopped_cpus, mycpu->gd_other_cpus)) {
191 db_printf("whoa, other_cpus: 0x%016jx, "
192 "stopped_cpus: 0x%016jx\n",
193 (uintmax_t)CPUMASK_LOWMASK(mycpu->gd_other_cpus),
194 (uintmax_t)CPUMASK_LOWMASK(stopped_cpus));
195 panic("stop_cpus() failed");
196 }
197 restart_cpus(stopped_cpus);
198 }
199
200 db_printf(" restarted\n");
201 crit_exit();
202
203 regs->tf_rip = ddb_regs.tf_rip;
204 regs->tf_rflags = ddb_regs.tf_rflags;
205 regs->tf_rax = ddb_regs.tf_rax;
206 regs->tf_rcx = ddb_regs.tf_rcx;
207 regs->tf_rdx = ddb_regs.tf_rdx;
208 regs->tf_rbx = ddb_regs.tf_rbx;
209
210 regs->tf_rsp = ddb_regs.tf_rsp;
211 regs->tf_ss = ddb_regs.tf_ss & 0xffff;
212
213 regs->tf_rbp = ddb_regs.tf_rbp;
214 regs->tf_rsi = ddb_regs.tf_rsi;
215 regs->tf_rdi = ddb_regs.tf_rdi;
216
217 regs->tf_r8 = ddb_regs.tf_r8;
218 regs->tf_r9 = ddb_regs.tf_r9;
219 regs->tf_r10 = ddb_regs.tf_r10;
220 regs->tf_r11 = ddb_regs.tf_r11;
221 regs->tf_r12 = ddb_regs.tf_r12;
222 regs->tf_r13 = ddb_regs.tf_r13;
223 regs->tf_r14 = ddb_regs.tf_r14;
224 regs->tf_r15 = ddb_regs.tf_r15;
225
226 /* regs->tf_es = ddb_regs.tf_es & 0xffff; */
227 /* regs->tf_fs = ddb_regs.tf_fs & 0xffff; */
228 /* regs->tf_gs = ddb_regs.tf_gs & 0xffff; */
229 regs->tf_cs = ddb_regs.tf_cs & 0xffff;
230 /* regs->tf_ds = ddb_regs.tf_ds & 0xffff; */
231 return (1);
232 }
233
234 /*
235 * Read bytes from kernel address space for debugger.
236 */
237 void
db_read_bytes(vm_offset_t addr,size_t size,char * data)238 db_read_bytes(vm_offset_t addr, size_t size, char *data)
239 {
240 char *src;
241
242 db_nofault = &db_jmpbuf;
243
244 src = (char *)addr;
245 while (size-- > 0)
246 *data++ = *src++;
247
248 db_nofault = NULL;
249 }
250
251 /*
252 * Write bytes to kernel address space for debugger.
253 */
254 void
db_write_bytes(vm_offset_t addr,size_t size,char * data)255 db_write_bytes(vm_offset_t addr, size_t size, char *data)
256 {
257 char *dst;
258 #if 0
259 vpte_t *ptep0 = NULL;
260 vpte_t oldmap0 = 0;
261 vm_offset_t addr1;
262 vpte_t *ptep1 = NULL;
263 vpte_t oldmap1 = 0;
264 #endif
265
266 db_nofault = &db_jmpbuf;
267 #if 0
268 if (addr > trunc_page((vm_offset_t)btext) - size &&
269 addr < round_page((vm_offset_t)etext)) {
270
271 ptep0 = pmap_kpte(addr);
272 oldmap0 = *ptep0;
273 *ptep0 |= VPTE_RW;
274
275 /* Map another page if the data crosses a page boundary. */
276 if ((*ptep0 & PG_PS) == 0) {
277 addr1 = trunc_page(addr + size - 1);
278 if (trunc_page(addr) != addr1) {
279 ptep1 = pmap_kpte(addr1);
280 oldmap1 = *ptep1;
281 *ptep1 |= VPTE_RW;
282 }
283 } else {
284 addr1 = trunc_4mpage(addr + size - 1);
285 if (trunc_4mpage(addr) != addr1) {
286 ptep1 = pmap_kpte(addr1);
287 oldmap1 = *ptep1;
288 *ptep1 |= VPTE_RW;
289 }
290 }
291
292 cpu_invltlb();
293 }
294 #endif
295
296 dst = (char *)addr;
297
298 while (size-- > 0)
299 *dst++ = *data++;
300
301 db_nofault = NULL;
302
303 #if 0
304 if (ptep0) {
305 *ptep0 = oldmap0;
306
307 if (ptep1)
308 *ptep1 = oldmap1;
309
310 cpu_invltlb();
311 }
312 #endif
313 }
314
315 /*
316 * The debugger sometimes needs to know the actual KVM address represented
317 * by the instruction pointer, stack pointer, or base pointer. Normally
318 * the actual KVM address is simply the contents of the register. However,
319 * if the debugger is entered from the BIOS or VM86 we need to figure out
320 * the offset from the segment register.
321 */
322 db_addr_t
PC_REGS(db_regs_t * regs)323 PC_REGS(db_regs_t *regs)
324 {
325 return(regs->tf_rip);
326 }
327
328 db_addr_t
SP_REGS(db_regs_t * regs)329 SP_REGS(db_regs_t *regs)
330 {
331 return(regs->tf_rsp);
332 }
333
334 db_addr_t
BP_REGS(db_regs_t * regs)335 BP_REGS(db_regs_t *regs)
336 {
337 return(regs->tf_rbp);
338 }
339
340 /*
341 * XXX
342 * Move this to machdep.c and allow it to be called if any debugger is
343 * installed.
344 */
345 void
Debugger(const char * msg)346 Debugger(const char *msg)
347 {
348 static volatile u_char in_Debugger;
349
350 /*
351 * XXX
352 * Do nothing if the console is in graphics mode. This is
353 * OK if the call is for the debugger hotkey but not if the call
354 * is a weak form of panicing.
355 */
356 if (cons_unavail && !(boothowto & RB_GDB)) {
357 /*
358 * If we are panicing, panic() expects cpus to be stopped
359 * when Debugger() returns.
360 */
361 if (panicstr != NULL)
362 stop_cpus(mycpu->gd_other_cpus);
363 return;
364 }
365
366 if (!in_Debugger) {
367 in_Debugger = 1;
368 db_printf("Debugger(\"%s\")\n", msg);
369
370 /*
371 * Save the pcb just in case the sysop entered the debugger
372 * manually and called dumpsys,
373 */
374 if (dumpthread == NULL) {
375 savectx(&dumppcb);
376 dumpthread = curthread;
377 }
378
379 breakpoint();
380 in_Debugger = 0;
381
382 /*
383 * Clear before returning from the debugger so a later panic
384 * saves the correct context.
385 */
386 dumpthread = NULL;
387 }
388 }
389