1 | /* $NetBSD: db_run.c,v 1.33 2014/09/19 17:29:01 matt Exp $ */ |
2 | |
3 | /* |
4 | * Mach Operating System |
5 | * Copyright (c) 1993-1990 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 the |
26 | * rights to redistribute these changes. |
27 | * |
28 | * Author: David B. Golub, Carnegie Mellon University |
29 | * Date: 7/90 |
30 | */ |
31 | |
32 | /* |
33 | * Commands to run process. |
34 | */ |
35 | |
36 | #include <sys/cdefs.h> |
37 | __KERNEL_RCSID(0, "$NetBSD: db_run.c,v 1.33 2014/09/19 17:29:01 matt Exp $" ); |
38 | |
39 | #include "opt_ddb.h" |
40 | |
41 | #include <sys/param.h> |
42 | #include <sys/proc.h> |
43 | |
44 | #include <machine/db_machdep.h> |
45 | |
46 | #include <ddb/db_run.h> |
47 | #include <ddb/db_access.h> |
48 | #include <ddb/db_break.h> |
49 | |
50 | int db_inst_count; |
51 | int db_load_count; |
52 | int db_store_count; |
53 | |
54 | #ifdef SOFTWARE_SSTEP |
55 | static void db_set_temp_breakpoint(db_breakpoint_t, db_addr_t); |
56 | static void db_delete_temp_breakpoint(db_breakpoint_t); |
57 | static struct db_breakpoint db_not_taken_bkpt; |
58 | static struct db_breakpoint db_taken_bkpt; |
59 | #endif |
60 | |
61 | #if defined(DDB) |
62 | #include <ddb/db_lex.h> |
63 | #include <ddb/db_watch.h> |
64 | #include <ddb/db_output.h> |
65 | #include <ddb/db_sym.h> |
66 | #include <ddb/db_extern.h> |
67 | |
68 | static int db_run_mode; |
69 | #define STEP_NONE 0 |
70 | #define STEP_ONCE 1 |
71 | #define STEP_RETURN 2 |
72 | #define STEP_CALLT 3 |
73 | #define STEP_CONTINUE 4 |
74 | #define STEP_INVISIBLE 5 |
75 | #define STEP_COUNT 6 |
76 | |
77 | static bool db_sstep_print; |
78 | static int db_loop_count; |
79 | static int db_call_depth; |
80 | |
81 | bool |
82 | db_stop_at_pc(db_regs_t *regs, bool *is_breakpoint) |
83 | { |
84 | db_addr_t pc; |
85 | db_breakpoint_t bkpt; |
86 | |
87 | pc = PC_REGS(regs); |
88 | |
89 | #ifdef FIXUP_PC_AFTER_BREAK |
90 | if (*is_breakpoint) { |
91 | /* |
92 | * Breakpoint trap. Regardless if we treat this as a |
93 | * real breakpoint (e.g. software single-step), fix up the PC. |
94 | */ |
95 | FIXUP_PC_AFTER_BREAK(regs); |
96 | pc = PC_REGS(regs); |
97 | } |
98 | #endif |
99 | |
100 | #ifdef SOFTWARE_SSTEP |
101 | /* |
102 | * If we stopped at one of the single-step breakpoints, say it's not |
103 | * really a breakpoint so that we don't skip over the real instruction. |
104 | */ |
105 | if (db_taken_bkpt.address == pc || db_not_taken_bkpt.address == pc) |
106 | *is_breakpoint = false; |
107 | #endif /* SOFTWARE_SSTEP */ |
108 | |
109 | db_clear_single_step(regs); |
110 | db_clear_breakpoints(); |
111 | db_clear_watchpoints(); |
112 | |
113 | /* |
114 | * Now check for a breakpoint at this address. |
115 | */ |
116 | bkpt = db_find_breakpoint_here(pc); |
117 | if (bkpt) { |
118 | if (--bkpt->count == 0) { |
119 | bkpt->count = bkpt->init_count; |
120 | *is_breakpoint = true; |
121 | return (true); /* stop here */ |
122 | } |
123 | } else if (*is_breakpoint) { |
124 | #ifdef PC_ADVANCE |
125 | PC_ADVANCE(regs); |
126 | #else |
127 | PC_REGS(regs) += BKPT_SIZE; |
128 | #endif |
129 | } |
130 | |
131 | *is_breakpoint = false; |
132 | |
133 | if (db_run_mode == STEP_INVISIBLE) { |
134 | db_run_mode = STEP_CONTINUE; |
135 | return (false); /* continue */ |
136 | } |
137 | if (db_run_mode == STEP_COUNT) { |
138 | return (false); /* continue */ |
139 | } |
140 | if (db_run_mode == STEP_ONCE) { |
141 | if (--db_loop_count > 0) { |
142 | if (db_sstep_print) { |
143 | db_printf("\t\t" ); |
144 | db_print_loc_and_inst(pc); |
145 | db_printf("\n" ); |
146 | } |
147 | return (false); /* continue */ |
148 | } |
149 | } |
150 | if (db_run_mode == STEP_RETURN) { |
151 | db_expr_t ins = db_get_value(pc, sizeof(int), false); |
152 | |
153 | /* continue until matching return */ |
154 | |
155 | if (!inst_trap_return(ins) && |
156 | (!inst_return(ins) || --db_call_depth != 0)) { |
157 | if (db_sstep_print) { |
158 | if (inst_call(ins) || inst_return(ins)) { |
159 | int i; |
160 | |
161 | db_printf("[after %6d] " , |
162 | db_inst_count); |
163 | for (i = db_call_depth; --i > 0; ) |
164 | db_printf(" " ); |
165 | db_print_loc_and_inst(pc); |
166 | db_printf("\n" ); |
167 | } |
168 | } |
169 | if (inst_call(ins)) |
170 | db_call_depth++; |
171 | return (false); /* continue */ |
172 | } |
173 | } |
174 | if (db_run_mode == STEP_CALLT) { |
175 | db_expr_t ins = db_get_value(pc, sizeof(int), false); |
176 | |
177 | /* continue until call or return */ |
178 | |
179 | if (!inst_call(ins) && |
180 | !inst_return(ins) && |
181 | !inst_trap_return(ins)) { |
182 | return (false); /* continue */ |
183 | } |
184 | } |
185 | db_run_mode = STEP_NONE; |
186 | return (true); |
187 | } |
188 | |
189 | void |
190 | db_restart_at_pc(db_regs_t *regs, bool watchpt) |
191 | { |
192 | db_addr_t pc = PC_REGS(regs); |
193 | #ifdef SOFTWARE_SSTEP |
194 | db_addr_t brpc; |
195 | #endif |
196 | |
197 | if ((db_run_mode == STEP_COUNT) || |
198 | (db_run_mode == STEP_RETURN) || |
199 | (db_run_mode == STEP_CALLT)) { |
200 | db_expr_t ins __unused; |
201 | |
202 | /* |
203 | * We are about to execute this instruction, |
204 | * so count it now. |
205 | */ |
206 | ins = db_get_value(pc, sizeof(int), false); |
207 | db_inst_count++; |
208 | db_load_count += inst_load(ins); |
209 | db_store_count += inst_store(ins); |
210 | |
211 | #ifdef SOFTWARE_SSTEP |
212 | /* |
213 | * Account for instructions in delay slots. |
214 | */ |
215 | brpc = next_instr_address(pc, true); |
216 | if ((brpc != pc) && |
217 | (inst_branch(ins) || inst_call(ins) || inst_return(ins))) { |
218 | ins = db_get_value(brpc, sizeof(int), false); |
219 | db_inst_count++; |
220 | db_load_count += inst_load(ins); |
221 | db_store_count += inst_store(ins); |
222 | } |
223 | #endif |
224 | } |
225 | |
226 | if (db_run_mode == STEP_CONTINUE) { |
227 | if (watchpt || db_find_breakpoint_here(pc)) { |
228 | /* |
229 | * Step over breakpoint/watchpoint. |
230 | */ |
231 | db_run_mode = STEP_INVISIBLE; |
232 | db_set_single_step(regs); |
233 | } else { |
234 | db_set_breakpoints(); |
235 | db_set_watchpoints(); |
236 | } |
237 | } else { |
238 | db_set_single_step(regs); |
239 | } |
240 | } |
241 | |
242 | void |
243 | db_single_step(db_regs_t *regs) |
244 | { |
245 | |
246 | if (db_run_mode == STEP_CONTINUE) { |
247 | db_run_mode = STEP_INVISIBLE; |
248 | db_set_single_step(regs); |
249 | } |
250 | } |
251 | |
252 | /* single-step */ |
253 | /*ARGSUSED*/ |
254 | void |
255 | db_single_step_cmd(db_expr_t addr, bool have_addr, |
256 | db_expr_t count, const char *modif) |
257 | { |
258 | bool print = false; |
259 | |
260 | if (count == -1) |
261 | count = 1; |
262 | |
263 | if (modif[0] == 'p') |
264 | print = true; |
265 | |
266 | db_run_mode = STEP_ONCE; |
267 | db_loop_count = count; |
268 | db_sstep_print = print; |
269 | db_inst_count = 0; |
270 | db_load_count = 0; |
271 | db_store_count = 0; |
272 | |
273 | db_cmd_loop_done = true; |
274 | } |
275 | |
276 | /* trace and print until call/return */ |
277 | /*ARGSUSED*/ |
278 | void |
279 | db_trace_until_call_cmd(db_expr_t addr, bool have_addr, |
280 | db_expr_t count, const char *modif) |
281 | { |
282 | bool print = false; |
283 | |
284 | if (modif[0] == 'p') |
285 | print = true; |
286 | |
287 | db_run_mode = STEP_CALLT; |
288 | db_sstep_print = print; |
289 | db_inst_count = 0; |
290 | db_load_count = 0; |
291 | db_store_count = 0; |
292 | |
293 | db_cmd_loop_done = true; |
294 | } |
295 | |
296 | /*ARGSUSED*/ |
297 | void |
298 | db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, |
299 | db_expr_t count, const char *modif) |
300 | { |
301 | bool print = false; |
302 | |
303 | if (modif[0] == 'p') |
304 | print = true; |
305 | |
306 | db_run_mode = STEP_RETURN; |
307 | db_call_depth = 1; |
308 | db_sstep_print = print; |
309 | db_inst_count = 0; |
310 | db_load_count = 0; |
311 | db_store_count = 0; |
312 | |
313 | db_cmd_loop_done = true; |
314 | } |
315 | |
316 | /* continue */ |
317 | /*ARGSUSED*/ |
318 | void |
319 | db_continue_cmd(db_expr_t addr, bool have_addr, |
320 | db_expr_t count, const char *modif) |
321 | { |
322 | |
323 | if (modif[0] == 'c') |
324 | db_run_mode = STEP_COUNT; |
325 | else |
326 | db_run_mode = STEP_CONTINUE; |
327 | db_inst_count = 0; |
328 | db_load_count = 0; |
329 | db_store_count = 0; |
330 | |
331 | db_cmd_loop_done = true; |
332 | } |
333 | #endif /* DDB */ |
334 | |
335 | #ifdef SOFTWARE_SSTEP |
336 | /* |
337 | * Software implementation of single-stepping. |
338 | * If your machine does not have a trace mode |
339 | * similar to the vax or sun ones you can use |
340 | * this implementation, done for the mips. |
341 | * Just define the above conditional and provide |
342 | * the functions/macros defined below. |
343 | * |
344 | * bool inst_branch(int inst) |
345 | * bool inst_call(int inst) |
346 | * returns true if the instruction might branch |
347 | * |
348 | * bool inst_return(int inst) |
349 | * returns true is the instruction will return to its caller |
350 | * |
351 | * bool inst_unconditional_flow_transfer(int inst) |
352 | * returns true if the instruction is an unconditional |
353 | * transter of flow (i.e. unconditional branch) |
354 | * |
355 | * db_addr_t branch_taken(int inst, db_addr_t pc, db_regs_t *regs) |
356 | * returns the target address of the branch |
357 | * |
358 | * db_addr_t next_instr_address(db_addr_t pc, bool bd) |
359 | * returns the address of the first instruction following the |
360 | * one at "pc", which is either in the taken path of the branch |
361 | * (bd == true) or not. This is for machines (e.g. mips) with |
362 | * branch delays. |
363 | * |
364 | * A single-step may involve at most 2 breakpoints - |
365 | * one for branch-not-taken and one for branch taken. |
366 | * If one of these addresses does not already have a breakpoint, |
367 | * we allocate a breakpoint and save it here. |
368 | * These breakpoints are deleted on return. |
369 | */ |
370 | |
371 | #if !defined(DDB) |
372 | /* XXX - don't check for existing breakpoints in KGDB-only case */ |
373 | #define db_find_breakpoint_here(pc) (0) |
374 | #endif |
375 | |
376 | void |
377 | db_set_single_step(db_regs_t *regs) |
378 | { |
379 | db_addr_t pc = PC_REGS(regs), brpc = pc; |
380 | bool unconditional; |
381 | unsigned int inst; |
382 | |
383 | /* |
384 | * User was stopped at pc, e.g. the instruction |
385 | * at pc was not executed. |
386 | */ |
387 | inst = db_get_value(pc, sizeof(int), false); |
388 | if (inst_branch(inst) || inst_call(inst) || inst_return(inst)) { |
389 | brpc = branch_taken(inst, pc, regs); |
390 | if (brpc != pc) { /* self-branches are hopeless */ |
391 | db_set_temp_breakpoint(&db_taken_bkpt, brpc); |
392 | } else |
393 | db_taken_bkpt.address = 0; |
394 | pc = next_instr_address(pc, true); |
395 | } |
396 | |
397 | /* |
398 | * Check if this control flow instruction is an |
399 | * unconditional transfer. |
400 | */ |
401 | unconditional = inst_unconditional_flow_transfer(inst); |
402 | |
403 | pc = next_instr_address(pc, false); |
404 | |
405 | /* |
406 | * We only set the sequential breakpoint if previous |
407 | * instruction was not an unconditional change of flow |
408 | * control. If the previous instruction is an |
409 | * unconditional change of flow control, setting a |
410 | * breakpoint in the next sequential location may set |
411 | * a breakpoint in data or in another routine, which |
412 | * could screw up in either the program or the debugger. |
413 | * (Consider, for instance, that the next sequential |
414 | * instruction is the start of a routine needed by the |
415 | * debugger.) |
416 | * |
417 | * Also, don't set both the taken and not-taken breakpoints |
418 | * in the same place even if the MD code would otherwise |
419 | * have us do so. |
420 | */ |
421 | if (unconditional == false && |
422 | db_find_breakpoint_here(pc) == 0 && |
423 | pc != brpc) |
424 | db_set_temp_breakpoint(&db_not_taken_bkpt, pc); |
425 | else |
426 | db_not_taken_bkpt.address = 0; |
427 | } |
428 | |
429 | void |
430 | db_clear_single_step(db_regs_t *regs) |
431 | { |
432 | |
433 | if (db_taken_bkpt.address != 0) |
434 | db_delete_temp_breakpoint(&db_taken_bkpt); |
435 | |
436 | if (db_not_taken_bkpt.address != 0) |
437 | db_delete_temp_breakpoint(&db_not_taken_bkpt); |
438 | } |
439 | |
440 | void |
441 | db_set_temp_breakpoint(db_breakpoint_t bkpt, db_addr_t addr) |
442 | { |
443 | |
444 | bkpt->map = NULL; |
445 | bkpt->address = addr; |
446 | /* bkpt->flags = BKPT_TEMP; - this is not used */ |
447 | bkpt->init_count = 1; |
448 | bkpt->count = 1; |
449 | |
450 | bkpt->bkpt_inst = db_get_value(bkpt->address, BKPT_SIZE, false); |
451 | db_put_value(bkpt->address, BKPT_SIZE, |
452 | BKPT_SET(bkpt->bkpt_inst, bkpt->address)); |
453 | } |
454 | |
455 | void |
456 | db_delete_temp_breakpoint(db_breakpoint_t bkpt) |
457 | { |
458 | |
459 | db_put_value(bkpt->address, BKPT_SIZE, bkpt->bkpt_inst); |
460 | bkpt->address = 0; |
461 | } |
462 | #endif /* SOFTWARE_SSTEP */ |
463 | |