Commit | Line | Data |
---|---|---|
dc7d5527 | 1 | /* |
53197fc4 | 2 | * Kernel Debug Core |
dc7d5527 JW |
3 | * |
4 | * Maintainer: Jason Wessel <jason.wessel@windriver.com> | |
5 | * | |
6 | * Copyright (C) 2000-2001 VERITAS Software Corporation. | |
7 | * Copyright (C) 2002-2004 Timesys Corporation | |
8 | * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com> | |
a2531293 | 9 | * Copyright (C) 2004 Pavel Machek <pavel@ucw.cz> |
dc7d5527 JW |
10 | * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> |
11 | * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. | |
53197fc4 | 12 | * Copyright (C) 2005-2009 Wind River Systems, Inc. |
dc7d5527 JW |
13 | * Copyright (C) 2007 MontaVista Software, Inc. |
14 | * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
15 | * | |
16 | * Contributors at various stages not listed above: | |
17 | * Jason Wessel ( jason.wessel@windriver.com ) | |
18 | * George Anzinger <george@mvista.com> | |
19 | * Anurekh Saxena (anurekh.saxena@timesys.com) | |
20 | * Lake Stevens Instrument Division (Glenn Engel) | |
21 | * Jim Kingdon, Cygnus Support. | |
22 | * | |
23 | * Original KGDB stub: David Grothe <dave@gcom.com>, | |
24 | * Tigran Aivazian <tigran@sco.com> | |
25 | * | |
26 | * This file is licensed under the terms of the GNU General Public License | |
27 | * version 2. This program is licensed "as is" without any warranty of any | |
28 | * kind, whether express or implied. | |
29 | */ | |
0f16996c FF |
30 | |
31 | #define pr_fmt(fmt) "KGDB: " fmt | |
32 | ||
dc7d5527 | 33 | #include <linux/pid_namespace.h> |
7c3078b6 | 34 | #include <linux/clocksource.h> |
16559ae4 | 35 | #include <linux/serial_core.h> |
dc7d5527 JW |
36 | #include <linux/interrupt.h> |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/console.h> | |
39 | #include <linux/threads.h> | |
40 | #include <linux/uaccess.h> | |
41 | #include <linux/kernel.h> | |
42 | #include <linux/module.h> | |
43 | #include <linux/ptrace.h> | |
dc7d5527 JW |
44 | #include <linux/string.h> |
45 | #include <linux/delay.h> | |
46 | #include <linux/sched.h> | |
47 | #include <linux/sysrq.h> | |
2366e047 | 48 | #include <linux/reboot.h> |
dc7d5527 JW |
49 | #include <linux/init.h> |
50 | #include <linux/kgdb.h> | |
dcc78711 | 51 | #include <linux/kdb.h> |
dc7d5527 JW |
52 | #include <linux/pid.h> |
53 | #include <linux/smp.h> | |
54 | #include <linux/mm.h> | |
615d6e87 | 55 | #include <linux/vmacache.h> |
fb70b588 | 56 | #include <linux/rcupdate.h> |
dc7d5527 JW |
57 | |
58 | #include <asm/cacheflush.h> | |
59 | #include <asm/byteorder.h> | |
60063497 | 60 | #include <linux/atomic.h> |
dc7d5527 | 61 | |
53197fc4 | 62 | #include "debug_core.h" |
dc7d5527 | 63 | |
53197fc4 | 64 | static int kgdb_break_asap; |
62fae312 | 65 | |
53197fc4 | 66 | struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
dc7d5527 JW |
67 | |
68 | /** | |
69 | * kgdb_connected - Is a host GDB connected to us? | |
70 | */ | |
71 | int kgdb_connected; | |
72 | EXPORT_SYMBOL_GPL(kgdb_connected); | |
73 | ||
74 | /* All the KGDB handlers are installed */ | |
f503b5ae | 75 | int kgdb_io_module_registered; |
dc7d5527 JW |
76 | |
77 | /* Guard for recursive entry */ | |
78 | static int exception_level; | |
79 | ||
53197fc4 | 80 | struct kgdb_io *dbg_io_ops; |
dc7d5527 JW |
81 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
82 | ||
bec4d62e JW |
83 | /* Action for the reboot notifiter, a global allow kdb to change it */ |
84 | static int kgdbreboot; | |
dc7d5527 JW |
85 | /* kgdb console driver is loaded */ |
86 | static int kgdb_con_registered; | |
87 | /* determine if kgdb console output should be used */ | |
88 | static int kgdb_use_con; | |
0b4b3827 JW |
89 | /* Flag for alternate operations for early debugging */ |
90 | bool dbg_is_early = true; | |
dcc78711 JW |
91 | /* Next cpu to become the master debug core */ |
92 | int dbg_switch_cpu; | |
93 | ||
94 | /* Use kdb or gdbserver mode */ | |
a0de055c | 95 | int dbg_kdb_mode = 1; |
dc7d5527 JW |
96 | |
97 | static int __init opt_kgdb_con(char *str) | |
98 | { | |
99 | kgdb_use_con = 1; | |
100 | return 0; | |
101 | } | |
102 | ||
103 | early_param("kgdbcon", opt_kgdb_con); | |
104 | ||
105 | module_param(kgdb_use_con, int, 0644); | |
bec4d62e | 106 | module_param(kgdbreboot, int, 0644); |
dc7d5527 JW |
107 | |
108 | /* | |
109 | * Holds information about breakpoints in a kernel. These breakpoints are | |
110 | * added and removed by gdb. | |
111 | */ | |
112 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { | |
113 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } | |
114 | }; | |
115 | ||
116 | /* | |
117 | * The CPU# of the active CPU, or -1 if none: | |
118 | */ | |
119 | atomic_t kgdb_active = ATOMIC_INIT(-1); | |
dcc78711 | 120 | EXPORT_SYMBOL_GPL(kgdb_active); |
dfee3a7b JW |
121 | static DEFINE_RAW_SPINLOCK(dbg_master_lock); |
122 | static DEFINE_RAW_SPINLOCK(dbg_slave_lock); | |
dc7d5527 JW |
123 | |
124 | /* | |
125 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early | |
126 | * bootup code (which might not have percpu set up yet): | |
127 | */ | |
dfee3a7b JW |
128 | static atomic_t masters_in_kgdb; |
129 | static atomic_t slaves_in_kgdb; | |
1cee5e35 | 130 | static atomic_t kgdb_break_tasklet_var; |
dc7d5527 JW |
131 | atomic_t kgdb_setting_breakpoint; |
132 | ||
133 | struct task_struct *kgdb_usethread; | |
134 | struct task_struct *kgdb_contthread; | |
135 | ||
136 | int kgdb_single_step; | |
53197fc4 | 137 | static pid_t kgdb_sstep_pid; |
dc7d5527 JW |
138 | |
139 | /* to keep track of the CPU which is doing the single stepping*/ | |
140 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); | |
141 | ||
142 | /* | |
143 | * If you are debugging a problem where roundup (the collection of | |
144 | * all other CPUs) is a problem [this should be extremely rare], | |
145 | * then use the nokgdbroundup option to avoid roundup. In that case | |
146 | * the other CPUs might interfere with your debugging context, so | |
147 | * use this with care: | |
148 | */ | |
688b744d | 149 | static int kgdb_do_roundup = 1; |
dc7d5527 JW |
150 | |
151 | static int __init opt_nokgdbroundup(char *str) | |
152 | { | |
153 | kgdb_do_roundup = 0; | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | early_param("nokgdbroundup", opt_nokgdbroundup); | |
159 | ||
160 | /* | |
161 | * Finally, some KGDB code :-) | |
162 | */ | |
163 | ||
164 | /* | |
165 | * Weak aliases for breakpoint management, | |
166 | * can be overriden by architectures when needed: | |
167 | */ | |
98b54aa1 | 168 | int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 JW |
169 | { |
170 | int err; | |
171 | ||
98b54aa1 JW |
172 | err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, |
173 | BREAK_INSTR_SIZE); | |
dc7d5527 JW |
174 | if (err) |
175 | return err; | |
98b54aa1 JW |
176 | err = probe_kernel_write((char *)bpt->bpt_addr, |
177 | arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); | |
178 | return err; | |
dc7d5527 JW |
179 | } |
180 | ||
98b54aa1 | 181 | int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 | 182 | { |
98b54aa1 JW |
183 | return probe_kernel_write((char *)bpt->bpt_addr, |
184 | (char *)bpt->saved_instr, BREAK_INSTR_SIZE); | |
dc7d5527 JW |
185 | } |
186 | ||
a9b60bf4 JW |
187 | int __weak kgdb_validate_break_address(unsigned long addr) |
188 | { | |
98b54aa1 | 189 | struct kgdb_bkpt tmp; |
a9b60bf4 | 190 | int err; |
98b54aa1 | 191 | /* Validate setting the breakpoint and then removing it. If the |
a9b60bf4 JW |
192 | * remove fails, the kernel needs to emit a bad message because we |
193 | * are deep trouble not being able to put things back the way we | |
194 | * found them. | |
195 | */ | |
98b54aa1 JW |
196 | tmp.bpt_addr = addr; |
197 | err = kgdb_arch_set_breakpoint(&tmp); | |
a9b60bf4 JW |
198 | if (err) |
199 | return err; | |
98b54aa1 | 200 | err = kgdb_arch_remove_breakpoint(&tmp); |
a9b60bf4 | 201 | if (err) |
0f16996c FF |
202 | pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n", |
203 | addr); | |
a9b60bf4 JW |
204 | return err; |
205 | } | |
206 | ||
dc7d5527 JW |
207 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
208 | { | |
209 | return instruction_pointer(regs); | |
210 | } | |
211 | ||
212 | int __weak kgdb_arch_init(void) | |
213 | { | |
214 | return 0; | |
215 | } | |
216 | ||
b4b8ac52 JW |
217 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
218 | { | |
219 | return 0; | |
220 | } | |
221 | ||
dc7d5527 JW |
222 | /* |
223 | * Some architectures need cache flushes when we set/clear a | |
224 | * breakpoint: | |
225 | */ | |
226 | static void kgdb_flush_swbreak_addr(unsigned long addr) | |
227 | { | |
228 | if (!CACHE_FLUSH_IS_SAFE) | |
229 | return; | |
230 | ||
615d6e87 DB |
231 | if (current->mm) { |
232 | int i; | |
233 | ||
234 | for (i = 0; i < VMACACHE_SIZE; i++) { | |
235 | if (!current->vmacache[i]) | |
236 | continue; | |
237 | flush_cache_range(current->vmacache[i], | |
238 | addr, addr + BREAK_INSTR_SIZE); | |
239 | } | |
dc7d5527 | 240 | } |
615d6e87 | 241 | |
1a9a3e76 JW |
242 | /* Force flush instruction cache if it was outside the mm */ |
243 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); | |
dc7d5527 JW |
244 | } |
245 | ||
246 | /* | |
247 | * SW breakpoint management: | |
248 | */ | |
53197fc4 | 249 | int dbg_activate_sw_breakpoints(void) |
dc7d5527 | 250 | { |
7f8b7ed6 JW |
251 | int error; |
252 | int ret = 0; | |
dc7d5527 JW |
253 | int i; |
254 | ||
255 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
256 | if (kgdb_break[i].state != BP_SET) | |
257 | continue; | |
258 | ||
98b54aa1 | 259 | error = kgdb_arch_set_breakpoint(&kgdb_break[i]); |
7f8b7ed6 JW |
260 | if (error) { |
261 | ret = error; | |
0f16996c FF |
262 | pr_info("BP install failed: %lx\n", |
263 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
264 | continue; |
265 | } | |
dc7d5527 | 266 | |
98b54aa1 | 267 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
268 | kgdb_break[i].state = BP_ACTIVE; |
269 | } | |
7f8b7ed6 | 270 | return ret; |
dc7d5527 JW |
271 | } |
272 | ||
53197fc4 | 273 | int dbg_set_sw_break(unsigned long addr) |
dc7d5527 JW |
274 | { |
275 | int err = kgdb_validate_break_address(addr); | |
276 | int breakno = -1; | |
277 | int i; | |
278 | ||
279 | if (err) | |
280 | return err; | |
281 | ||
282 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
283 | if ((kgdb_break[i].state == BP_SET) && | |
284 | (kgdb_break[i].bpt_addr == addr)) | |
285 | return -EEXIST; | |
286 | } | |
287 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
288 | if (kgdb_break[i].state == BP_REMOVED && | |
289 | kgdb_break[i].bpt_addr == addr) { | |
290 | breakno = i; | |
291 | break; | |
292 | } | |
293 | } | |
294 | ||
295 | if (breakno == -1) { | |
296 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
297 | if (kgdb_break[i].state == BP_UNDEFINED) { | |
298 | breakno = i; | |
299 | break; | |
300 | } | |
301 | } | |
302 | } | |
303 | ||
304 | if (breakno == -1) | |
305 | return -E2BIG; | |
306 | ||
307 | kgdb_break[breakno].state = BP_SET; | |
308 | kgdb_break[breakno].type = BP_BREAKPOINT; | |
309 | kgdb_break[breakno].bpt_addr = addr; | |
310 | ||
311 | return 0; | |
312 | } | |
313 | ||
dcc78711 | 314 | int dbg_deactivate_sw_breakpoints(void) |
dc7d5527 | 315 | { |
7f8b7ed6 JW |
316 | int error; |
317 | int ret = 0; | |
dc7d5527 JW |
318 | int i; |
319 | ||
320 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
321 | if (kgdb_break[i].state != BP_ACTIVE) | |
322 | continue; | |
98b54aa1 | 323 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
7f8b7ed6 | 324 | if (error) { |
0f16996c FF |
325 | pr_info("BP remove failed: %lx\n", |
326 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
327 | ret = error; |
328 | } | |
dc7d5527 | 329 | |
98b54aa1 | 330 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
331 | kgdb_break[i].state = BP_SET; |
332 | } | |
7f8b7ed6 | 333 | return ret; |
dc7d5527 JW |
334 | } |
335 | ||
53197fc4 | 336 | int dbg_remove_sw_break(unsigned long addr) |
dc7d5527 JW |
337 | { |
338 | int i; | |
339 | ||
340 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
341 | if ((kgdb_break[i].state == BP_SET) && | |
342 | (kgdb_break[i].bpt_addr == addr)) { | |
343 | kgdb_break[i].state = BP_REMOVED; | |
344 | return 0; | |
345 | } | |
346 | } | |
347 | return -ENOENT; | |
348 | } | |
349 | ||
350 | int kgdb_isremovedbreak(unsigned long addr) | |
351 | { | |
352 | int i; | |
353 | ||
354 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
355 | if ((kgdb_break[i].state == BP_REMOVED) && | |
356 | (kgdb_break[i].bpt_addr == addr)) | |
357 | return 1; | |
358 | } | |
359 | return 0; | |
360 | } | |
361 | ||
53197fc4 | 362 | int dbg_remove_all_break(void) |
dc7d5527 | 363 | { |
dc7d5527 JW |
364 | int error; |
365 | int i; | |
366 | ||
367 | /* Clear memory breakpoints. */ | |
368 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
737a460f JW |
369 | if (kgdb_break[i].state != BP_ACTIVE) |
370 | goto setundefined; | |
98b54aa1 | 371 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
dc7d5527 | 372 | if (error) |
0f16996c | 373 | pr_err("breakpoint remove failed: %lx\n", |
98b54aa1 | 374 | kgdb_break[i].bpt_addr); |
737a460f JW |
375 | setundefined: |
376 | kgdb_break[i].state = BP_UNDEFINED; | |
dc7d5527 JW |
377 | } |
378 | ||
379 | /* Clear hardware breakpoints. */ | |
380 | if (arch_kgdb_ops.remove_all_hw_break) | |
381 | arch_kgdb_ops.remove_all_hw_break(); | |
382 | ||
383 | return 0; | |
384 | } | |
385 | ||
dc7d5527 JW |
386 | /* |
387 | * Return true if there is a valid kgdb I/O module. Also if no | |
388 | * debugger is attached a message can be printed to the console about | |
389 | * waiting for the debugger to attach. | |
390 | * | |
391 | * The print_wait argument is only to be true when called from inside | |
392 | * the core kgdb_handle_exception, because it will wait for the | |
393 | * debugger to attach. | |
394 | */ | |
395 | static int kgdb_io_ready(int print_wait) | |
396 | { | |
53197fc4 | 397 | if (!dbg_io_ops) |
dc7d5527 JW |
398 | return 0; |
399 | if (kgdb_connected) | |
400 | return 1; | |
401 | if (atomic_read(&kgdb_setting_breakpoint)) | |
402 | return 1; | |
dcc78711 JW |
403 | if (print_wait) { |
404 | #ifdef CONFIG_KGDB_KDB | |
405 | if (!dbg_kdb_mode) | |
0f16996c | 406 | pr_crit("waiting... or $3#33 for KDB\n"); |
dcc78711 | 407 | #else |
0f16996c | 408 | pr_crit("Waiting for remote debugger\n"); |
dcc78711 JW |
409 | #endif |
410 | } | |
dc7d5527 JW |
411 | return 1; |
412 | } | |
413 | ||
dc7d5527 JW |
414 | static int kgdb_reenter_check(struct kgdb_state *ks) |
415 | { | |
416 | unsigned long addr; | |
417 | ||
418 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) | |
419 | return 0; | |
420 | ||
421 | /* Panic on recursive debugger calls: */ | |
422 | exception_level++; | |
423 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); | |
dcc78711 | 424 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 JW |
425 | |
426 | /* | |
427 | * If the break point removed ok at the place exception | |
428 | * occurred, try to recover and print a warning to the end | |
429 | * user because the user planted a breakpoint in a place that | |
430 | * KGDB needs in order to function. | |
431 | */ | |
53197fc4 | 432 | if (dbg_remove_sw_break(addr) == 0) { |
dc7d5527 JW |
433 | exception_level = 0; |
434 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); | |
53197fc4 | 435 | dbg_activate_sw_breakpoints(); |
0f16996c | 436 | pr_crit("re-enter error: breakpoint removed %lx\n", addr); |
dc7d5527 JW |
437 | WARN_ON_ONCE(1); |
438 | ||
439 | return 1; | |
440 | } | |
53197fc4 | 441 | dbg_remove_all_break(); |
dc7d5527 JW |
442 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
443 | ||
444 | if (exception_level > 1) { | |
445 | dump_stack(); | |
446 | panic("Recursive entry to debugger"); | |
447 | } | |
448 | ||
0f16996c | 449 | pr_crit("re-enter exception: ALL breakpoints killed\n"); |
6d906340 JW |
450 | #ifdef CONFIG_KGDB_KDB |
451 | /* Allow kdb to debug itself one level */ | |
452 | return 0; | |
453 | #endif | |
dc7d5527 JW |
454 | dump_stack(); |
455 | panic("Recursive entry to debugger"); | |
456 | ||
457 | return 1; | |
458 | } | |
459 | ||
16cdc628 JW |
460 | static void dbg_touch_watchdogs(void) |
461 | { | |
462 | touch_softlockup_watchdog_sync(); | |
463 | clocksource_touch_watchdog(); | |
fb70b588 | 464 | rcu_cpu_stall_reset(); |
16cdc628 JW |
465 | } |
466 | ||
dfee3a7b JW |
467 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, |
468 | int exception_state) | |
dc7d5527 | 469 | { |
dc7d5527 | 470 | unsigned long flags; |
028e7b17 | 471 | int sstep_tries = 100; |
dcc78711 | 472 | int error; |
dfee3a7b | 473 | int cpu; |
4da75b9c | 474 | int trace_on = 0; |
dfee3a7b | 475 | int online_cpus = num_online_cpus(); |
a1465d2f | 476 | u64 time_left; |
c1bb9a9c | 477 | |
dfee3a7b JW |
478 | kgdb_info[ks->cpu].enter_kgdb++; |
479 | kgdb_info[ks->cpu].exception_state |= exception_state; | |
480 | ||
481 | if (exception_state == DCPU_WANT_MASTER) | |
482 | atomic_inc(&masters_in_kgdb); | |
483 | else | |
484 | atomic_inc(&slaves_in_kgdb); | |
d7ba979d DD |
485 | |
486 | if (arch_kgdb_ops.disable_hw_break) | |
487 | arch_kgdb_ops.disable_hw_break(regs); | |
c1bb9a9c | 488 | |
dc7d5527 JW |
489 | acquirelock: |
490 | /* | |
491 | * Interrupts will be restored by the 'trap return' code, except when | |
492 | * single stepping. | |
493 | */ | |
494 | local_irq_save(flags); | |
495 | ||
62fae312 JW |
496 | cpu = ks->cpu; |
497 | kgdb_info[cpu].debuggerinfo = regs; | |
498 | kgdb_info[cpu].task = current; | |
dcc78711 JW |
499 | kgdb_info[cpu].ret_state = 0; |
500 | kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; | |
dc7d5527 | 501 | |
dfee3a7b JW |
502 | /* Make sure the above info reaches the primary CPU */ |
503 | smp_mb(); | |
504 | ||
505 | if (exception_level == 1) { | |
506 | if (raw_spin_trylock(&dbg_master_lock)) | |
507 | atomic_xchg(&kgdb_active, cpu); | |
6d906340 | 508 | goto cpu_master_loop; |
dfee3a7b | 509 | } |
6d906340 | 510 | |
dc7d5527 | 511 | /* |
62fae312 JW |
512 | * CPU will loop if it is a slave or request to become a kgdb |
513 | * master cpu and acquire the kgdb_active lock: | |
dc7d5527 | 514 | */ |
62fae312 | 515 | while (1) { |
dcc78711 JW |
516 | cpu_loop: |
517 | if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) { | |
518 | kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER; | |
519 | goto cpu_master_loop; | |
520 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { | |
dfee3a7b JW |
521 | if (raw_spin_trylock(&dbg_master_lock)) { |
522 | atomic_xchg(&kgdb_active, cpu); | |
62fae312 | 523 | break; |
dfee3a7b | 524 | } |
62fae312 | 525 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
dfee3a7b | 526 | if (!raw_spin_is_locked(&dbg_slave_lock)) |
62fae312 JW |
527 | goto return_normal; |
528 | } else { | |
529 | return_normal: | |
530 | /* Return to normal operation by executing any | |
531 | * hw breakpoint fixup. | |
532 | */ | |
533 | if (arch_kgdb_ops.correct_hw_break) | |
534 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
535 | if (trace_on) |
536 | tracing_on(); | |
dfee3a7b JW |
537 | kgdb_info[cpu].exception_state &= |
538 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
539 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 540 | smp_mb__before_atomic(); |
dfee3a7b | 541 | atomic_dec(&slaves_in_kgdb); |
16cdc628 | 542 | dbg_touch_watchdogs(); |
62fae312 JW |
543 | local_irq_restore(flags); |
544 | return 0; | |
545 | } | |
dc7d5527 | 546 | cpu_relax(); |
62fae312 | 547 | } |
dc7d5527 JW |
548 | |
549 | /* | |
028e7b17 | 550 | * For single stepping, try to only enter on the processor |
25985edc | 551 | * that was single stepping. To guard against a deadlock, the |
028e7b17 JW |
552 | * kernel will only try for the value of sstep_tries before |
553 | * giving up and continuing on. | |
dc7d5527 JW |
554 | */ |
555 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && | |
028e7b17 JW |
556 | (kgdb_info[cpu].task && |
557 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { | |
dc7d5527 | 558 | atomic_set(&kgdb_active, -1); |
dfee3a7b | 559 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 560 | dbg_touch_watchdogs(); |
dc7d5527 JW |
561 | local_irq_restore(flags); |
562 | ||
563 | goto acquirelock; | |
564 | } | |
565 | ||
566 | if (!kgdb_io_ready(1)) { | |
dcc78711 | 567 | kgdb_info[cpu].ret_state = 1; |
53197fc4 | 568 | goto kgdb_restore; /* No I/O connection, resume the system */ |
dc7d5527 JW |
569 | } |
570 | ||
571 | /* | |
572 | * Don't enter if we have hit a removed breakpoint. | |
573 | */ | |
574 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) | |
575 | goto kgdb_restore; | |
576 | ||
577 | /* Call the I/O driver's pre_exception routine */ | |
53197fc4 JW |
578 | if (dbg_io_ops->pre_exception) |
579 | dbg_io_ops->pre_exception(); | |
dc7d5527 | 580 | |
dc7d5527 JW |
581 | /* |
582 | * Get the passive CPU lock which will hold all the non-primary | |
583 | * CPU in a spin state while the debugger is active | |
584 | */ | |
dfee3a7b JW |
585 | if (!kgdb_single_step) |
586 | raw_spin_lock(&dbg_slave_lock); | |
dc7d5527 | 587 | |
56fb7093 | 588 | #ifdef CONFIG_SMP |
8daaa5f8 MT |
589 | /* If send_ready set, slaves are already waiting */ |
590 | if (ks->send_ready) | |
591 | atomic_set(ks->send_ready, 1); | |
592 | ||
56fb7093 | 593 | /* Signal the other CPUs to enter kgdb_wait() */ |
8daaa5f8 | 594 | else if ((!kgdb_single_step) && kgdb_do_roundup) |
56fb7093 JW |
595 | kgdb_roundup_cpus(flags); |
596 | #endif | |
597 | ||
dc7d5527 JW |
598 | /* |
599 | * Wait for the other CPUs to be notified and be waiting for us: | |
600 | */ | |
a1465d2f DT |
601 | time_left = loops_per_jiffy * HZ; |
602 | while (kgdb_do_roundup && --time_left && | |
603 | (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) != | |
604 | online_cpus) | |
dfee3a7b | 605 | cpu_relax(); |
a1465d2f DT |
606 | if (!time_left) |
607 | pr_crit("KGDB: Timed out waiting for secondary CPUs.\n"); | |
dc7d5527 JW |
608 | |
609 | /* | |
610 | * At this point the primary processor is completely | |
611 | * in the debugger and all secondary CPUs are quiescent | |
612 | */ | |
dcc78711 | 613 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 | 614 | kgdb_single_step = 0; |
d7161a65 | 615 | kgdb_contthread = current; |
dc7d5527 | 616 | exception_level = 0; |
4da75b9c JW |
617 | trace_on = tracing_is_on(); |
618 | if (trace_on) | |
619 | tracing_off(); | |
dc7d5527 | 620 | |
dcc78711 JW |
621 | while (1) { |
622 | cpu_master_loop: | |
623 | if (dbg_kdb_mode) { | |
624 | kgdb_connected = 1; | |
625 | error = kdb_stub(ks); | |
3fa43aba JW |
626 | if (error == -1) |
627 | continue; | |
b0679c63 | 628 | kgdb_connected = 0; |
dcc78711 JW |
629 | } else { |
630 | error = gdb_serial_stub(ks); | |
631 | } | |
632 | ||
633 | if (error == DBG_PASS_EVENT) { | |
634 | dbg_kdb_mode = !dbg_kdb_mode; | |
dcc78711 | 635 | } else if (error == DBG_SWITCH_CPU_EVENT) { |
495363d3 JW |
636 | kgdb_info[dbg_switch_cpu].exception_state |= |
637 | DCPU_NEXT_MASTER; | |
dcc78711 JW |
638 | goto cpu_loop; |
639 | } else { | |
640 | kgdb_info[cpu].ret_state = error; | |
641 | break; | |
642 | } | |
643 | } | |
dc7d5527 JW |
644 | |
645 | /* Call the I/O driver's post_exception routine */ | |
53197fc4 JW |
646 | if (dbg_io_ops->post_exception) |
647 | dbg_io_ops->post_exception(); | |
dc7d5527 | 648 | |
d7161a65 | 649 | if (!kgdb_single_step) { |
dfee3a7b JW |
650 | raw_spin_unlock(&dbg_slave_lock); |
651 | /* Wait till all the CPUs have quit from the debugger. */ | |
652 | while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb)) | |
653 | cpu_relax(); | |
dc7d5527 JW |
654 | } |
655 | ||
656 | kgdb_restore: | |
028e7b17 JW |
657 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
658 | int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); | |
659 | if (kgdb_info[sstep_cpu].task) | |
660 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; | |
661 | else | |
662 | kgdb_sstep_pid = 0; | |
663 | } | |
c1bb9a9c DD |
664 | if (arch_kgdb_ops.correct_hw_break) |
665 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
666 | if (trace_on) |
667 | tracing_on(); | |
dfee3a7b JW |
668 | |
669 | kgdb_info[cpu].exception_state &= | |
670 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
671 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 672 | smp_mb__before_atomic(); |
dfee3a7b | 673 | atomic_dec(&masters_in_kgdb); |
dc7d5527 JW |
674 | /* Free kgdb_active */ |
675 | atomic_set(&kgdb_active, -1); | |
dfee3a7b | 676 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 677 | dbg_touch_watchdogs(); |
dc7d5527 JW |
678 | local_irq_restore(flags); |
679 | ||
dcc78711 | 680 | return kgdb_info[cpu].ret_state; |
dc7d5527 JW |
681 | } |
682 | ||
62fae312 JW |
683 | /* |
684 | * kgdb_handle_exception() - main entry point from a kernel exception | |
685 | * | |
686 | * Locking hierarchy: | |
687 | * interface locks, if any (begin_session) | |
688 | * kgdb lock (kgdb_active) | |
689 | */ | |
690 | int | |
691 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) | |
692 | { | |
693 | struct kgdb_state kgdb_var; | |
694 | struct kgdb_state *ks = &kgdb_var; | |
5a14fead AV |
695 | int ret = 0; |
696 | ||
697 | if (arch_kgdb_ops.enable_nmi) | |
698 | arch_kgdb_ops.enable_nmi(0); | |
62fae312 | 699 | |
8daaa5f8 | 700 | memset(ks, 0, sizeof(struct kgdb_state)); |
62fae312 JW |
701 | ks->cpu = raw_smp_processor_id(); |
702 | ks->ex_vector = evector; | |
703 | ks->signo = signo; | |
62fae312 | 704 | ks->err_code = ecode; |
62fae312 JW |
705 | ks->linux_regs = regs; |
706 | ||
707 | if (kgdb_reenter_check(ks)) | |
5a14fead | 708 | goto out; /* Ouch, double exception ! */ |
dfee3a7b | 709 | if (kgdb_info[ks->cpu].enter_kgdb != 0) |
5a14fead | 710 | goto out; |
dfee3a7b | 711 | |
5a14fead AV |
712 | ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
713 | out: | |
714 | if (arch_kgdb_ops.enable_nmi) | |
715 | arch_kgdb_ops.enable_nmi(1); | |
716 | return ret; | |
62fae312 JW |
717 | } |
718 | ||
f30fed10 JW |
719 | /* |
720 | * GDB places a breakpoint at this function to know dynamically | |
721 | * loaded objects. It's not defined static so that only one instance with this | |
722 | * name exists in the kernel. | |
723 | */ | |
724 | ||
725 | static int module_event(struct notifier_block *self, unsigned long val, | |
726 | void *data) | |
727 | { | |
728 | return 0; | |
729 | } | |
730 | ||
731 | static struct notifier_block dbg_module_load_nb = { | |
732 | .notifier_call = module_event, | |
733 | }; | |
734 | ||
dc7d5527 JW |
735 | int kgdb_nmicallback(int cpu, void *regs) |
736 | { | |
737 | #ifdef CONFIG_SMP | |
62fae312 JW |
738 | struct kgdb_state kgdb_var; |
739 | struct kgdb_state *ks = &kgdb_var; | |
740 | ||
741 | memset(ks, 0, sizeof(struct kgdb_state)); | |
742 | ks->cpu = cpu; | |
743 | ks->linux_regs = regs; | |
744 | ||
dfee3a7b JW |
745 | if (kgdb_info[ks->cpu].enter_kgdb == 0 && |
746 | raw_spin_is_locked(&dbg_master_lock)) { | |
747 | kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); | |
dc7d5527 JW |
748 | return 0; |
749 | } | |
750 | #endif | |
751 | return 1; | |
752 | } | |
753 | ||
fc8b1374 MT |
754 | int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, |
755 | atomic_t *send_ready) | |
8daaa5f8 MT |
756 | { |
757 | #ifdef CONFIG_SMP | |
758 | if (!kgdb_io_ready(0) || !send_ready) | |
759 | return 1; | |
760 | ||
761 | if (kgdb_info[cpu].enter_kgdb == 0) { | |
762 | struct kgdb_state kgdb_var; | |
763 | struct kgdb_state *ks = &kgdb_var; | |
764 | ||
765 | memset(ks, 0, sizeof(struct kgdb_state)); | |
766 | ks->cpu = cpu; | |
767 | ks->ex_vector = trapnr; | |
768 | ks->signo = SIGTRAP; | |
fc8b1374 | 769 | ks->err_code = err_code; |
8daaa5f8 MT |
770 | ks->linux_regs = regs; |
771 | ks->send_ready = send_ready; | |
772 | kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); | |
773 | return 0; | |
774 | } | |
775 | #endif | |
776 | return 1; | |
777 | } | |
778 | ||
aabdc3b8 JW |
779 | static void kgdb_console_write(struct console *co, const char *s, |
780 | unsigned count) | |
dc7d5527 JW |
781 | { |
782 | unsigned long flags; | |
783 | ||
784 | /* If we're debugging, or KGDB has not connected, don't try | |
785 | * and print. */ | |
dcc78711 | 786 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) |
dc7d5527 JW |
787 | return; |
788 | ||
789 | local_irq_save(flags); | |
53197fc4 | 790 | gdbstub_msg_write(s, count); |
dc7d5527 JW |
791 | local_irq_restore(flags); |
792 | } | |
793 | ||
794 | static struct console kgdbcons = { | |
795 | .name = "kgdb", | |
796 | .write = kgdb_console_write, | |
797 | .flags = CON_PRINTBUFFER | CON_ENABLED, | |
798 | .index = -1, | |
799 | }; | |
800 | ||
801 | #ifdef CONFIG_MAGIC_SYSRQ | |
1495cc9d | 802 | static void sysrq_handle_dbg(int key) |
dc7d5527 | 803 | { |
53197fc4 | 804 | if (!dbg_io_ops) { |
0f16996c | 805 | pr_crit("ERROR: No KGDB I/O module available\n"); |
dc7d5527 JW |
806 | return; |
807 | } | |
dcc78711 JW |
808 | if (!kgdb_connected) { |
809 | #ifdef CONFIG_KGDB_KDB | |
810 | if (!dbg_kdb_mode) | |
0f16996c | 811 | pr_crit("KGDB or $3#33 for KDB\n"); |
dcc78711 | 812 | #else |
0f16996c | 813 | pr_crit("Entering KGDB\n"); |
dcc78711 JW |
814 | #endif |
815 | } | |
dc7d5527 JW |
816 | |
817 | kgdb_breakpoint(); | |
818 | } | |
819 | ||
53197fc4 JW |
820 | static struct sysrq_key_op sysrq_dbg_op = { |
821 | .handler = sysrq_handle_dbg, | |
f3456509 | 822 | .help_msg = "debug(g)", |
364b5b7b | 823 | .action_msg = "DEBUG", |
dc7d5527 JW |
824 | }; |
825 | #endif | |
826 | ||
4402c153 JW |
827 | static int kgdb_panic_event(struct notifier_block *self, |
828 | unsigned long val, | |
829 | void *data) | |
830 | { | |
831 | if (dbg_kdb_mode) | |
832 | kdb_printf("PANIC: %s\n", (char *)data); | |
833 | kgdb_breakpoint(); | |
834 | return NOTIFY_DONE; | |
835 | } | |
836 | ||
837 | static struct notifier_block kgdb_panic_event_nb = { | |
838 | .notifier_call = kgdb_panic_event, | |
839 | .priority = INT_MAX, | |
840 | }; | |
841 | ||
0b4b3827 JW |
842 | void __weak kgdb_arch_late(void) |
843 | { | |
844 | } | |
845 | ||
846 | void __init dbg_late_init(void) | |
847 | { | |
848 | dbg_is_early = false; | |
849 | if (kgdb_io_module_registered) | |
850 | kgdb_arch_late(); | |
851 | kdb_init(KDB_INIT_FULL); | |
852 | } | |
853 | ||
2366e047 JW |
854 | static int |
855 | dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x) | |
856 | { | |
bec4d62e JW |
857 | /* |
858 | * Take the following action on reboot notify depending on value: | |
859 | * 1 == Enter debugger | |
860 | * 0 == [the default] detatch debug client | |
861 | * -1 == Do nothing... and use this until the board resets | |
862 | */ | |
863 | switch (kgdbreboot) { | |
864 | case 1: | |
865 | kgdb_breakpoint(); | |
866 | case -1: | |
867 | goto done; | |
868 | } | |
2366e047 JW |
869 | if (!dbg_kdb_mode) |
870 | gdbstub_exit(code); | |
bec4d62e | 871 | done: |
2366e047 JW |
872 | return NOTIFY_DONE; |
873 | } | |
874 | ||
875 | static struct notifier_block dbg_reboot_notifier = { | |
876 | .notifier_call = dbg_notify_reboot, | |
877 | .next = NULL, | |
878 | .priority = INT_MAX, | |
879 | }; | |
880 | ||
dc7d5527 JW |
881 | static void kgdb_register_callbacks(void) |
882 | { | |
883 | if (!kgdb_io_module_registered) { | |
884 | kgdb_io_module_registered = 1; | |
885 | kgdb_arch_init(); | |
0b4b3827 JW |
886 | if (!dbg_is_early) |
887 | kgdb_arch_late(); | |
f30fed10 | 888 | register_module_notifier(&dbg_module_load_nb); |
2366e047 | 889 | register_reboot_notifier(&dbg_reboot_notifier); |
4402c153 JW |
890 | atomic_notifier_chain_register(&panic_notifier_list, |
891 | &kgdb_panic_event_nb); | |
dc7d5527 | 892 | #ifdef CONFIG_MAGIC_SYSRQ |
53197fc4 | 893 | register_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
894 | #endif |
895 | if (kgdb_use_con && !kgdb_con_registered) { | |
896 | register_console(&kgdbcons); | |
897 | kgdb_con_registered = 1; | |
898 | } | |
899 | } | |
900 | } | |
901 | ||
902 | static void kgdb_unregister_callbacks(void) | |
903 | { | |
904 | /* | |
905 | * When this routine is called KGDB should unregister from the | |
906 | * panic handler and clean up, making sure it is not handling any | |
907 | * break exceptions at the time. | |
908 | */ | |
909 | if (kgdb_io_module_registered) { | |
910 | kgdb_io_module_registered = 0; | |
2366e047 | 911 | unregister_reboot_notifier(&dbg_reboot_notifier); |
f30fed10 | 912 | unregister_module_notifier(&dbg_module_load_nb); |
4402c153 JW |
913 | atomic_notifier_chain_unregister(&panic_notifier_list, |
914 | &kgdb_panic_event_nb); | |
dc7d5527 JW |
915 | kgdb_arch_exit(); |
916 | #ifdef CONFIG_MAGIC_SYSRQ | |
53197fc4 | 917 | unregister_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
918 | #endif |
919 | if (kgdb_con_registered) { | |
920 | unregister_console(&kgdbcons); | |
921 | kgdb_con_registered = 0; | |
922 | } | |
923 | } | |
924 | } | |
925 | ||
1cee5e35 JW |
926 | /* |
927 | * There are times a tasklet needs to be used vs a compiled in | |
928 | * break point so as to cause an exception outside a kgdb I/O module, | |
929 | * such as is the case with kgdboe, where calling a breakpoint in the | |
930 | * I/O driver itself would be fatal. | |
931 | */ | |
932 | static void kgdb_tasklet_bpt(unsigned long ing) | |
933 | { | |
934 | kgdb_breakpoint(); | |
935 | atomic_set(&kgdb_break_tasklet_var, 0); | |
936 | } | |
937 | ||
938 | static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0); | |
939 | ||
940 | void kgdb_schedule_breakpoint(void) | |
941 | { | |
942 | if (atomic_read(&kgdb_break_tasklet_var) || | |
943 | atomic_read(&kgdb_active) != -1 || | |
944 | atomic_read(&kgdb_setting_breakpoint)) | |
945 | return; | |
946 | atomic_inc(&kgdb_break_tasklet_var); | |
947 | tasklet_schedule(&kgdb_tasklet_breakpoint); | |
948 | } | |
949 | EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint); | |
950 | ||
dc7d5527 JW |
951 | static void kgdb_initial_breakpoint(void) |
952 | { | |
953 | kgdb_break_asap = 0; | |
954 | ||
0f16996c | 955 | pr_crit("Waiting for connection from remote gdb...\n"); |
dc7d5527 JW |
956 | kgdb_breakpoint(); |
957 | } | |
958 | ||
959 | /** | |
737a460f | 960 | * kgdb_register_io_module - register KGDB IO module |
53197fc4 | 961 | * @new_dbg_io_ops: the io ops vector |
dc7d5527 JW |
962 | * |
963 | * Register it with the KGDB core. | |
964 | */ | |
53197fc4 | 965 | int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
dc7d5527 JW |
966 | { |
967 | int err; | |
968 | ||
969 | spin_lock(&kgdb_registration_lock); | |
970 | ||
53197fc4 | 971 | if (dbg_io_ops) { |
dc7d5527 JW |
972 | spin_unlock(&kgdb_registration_lock); |
973 | ||
0f16996c | 974 | pr_err("Another I/O driver is already registered with KGDB\n"); |
dc7d5527 JW |
975 | return -EBUSY; |
976 | } | |
977 | ||
53197fc4 JW |
978 | if (new_dbg_io_ops->init) { |
979 | err = new_dbg_io_ops->init(); | |
dc7d5527 JW |
980 | if (err) { |
981 | spin_unlock(&kgdb_registration_lock); | |
982 | return err; | |
983 | } | |
984 | } | |
985 | ||
53197fc4 | 986 | dbg_io_ops = new_dbg_io_ops; |
dc7d5527 JW |
987 | |
988 | spin_unlock(&kgdb_registration_lock); | |
989 | ||
0f16996c | 990 | pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name); |
dc7d5527 JW |
991 | |
992 | /* Arm KGDB now. */ | |
993 | kgdb_register_callbacks(); | |
994 | ||
995 | if (kgdb_break_asap) | |
996 | kgdb_initial_breakpoint(); | |
997 | ||
998 | return 0; | |
999 | } | |
1000 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); | |
1001 | ||
1002 | /** | |
1003 | * kkgdb_unregister_io_module - unregister KGDB IO module | |
53197fc4 | 1004 | * @old_dbg_io_ops: the io ops vector |
dc7d5527 JW |
1005 | * |
1006 | * Unregister it with the KGDB core. | |
1007 | */ | |
53197fc4 | 1008 | void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
dc7d5527 JW |
1009 | { |
1010 | BUG_ON(kgdb_connected); | |
1011 | ||
1012 | /* | |
1013 | * KGDB is no longer able to communicate out, so | |
1014 | * unregister our callbacks and reset state. | |
1015 | */ | |
1016 | kgdb_unregister_callbacks(); | |
1017 | ||
1018 | spin_lock(&kgdb_registration_lock); | |
1019 | ||
53197fc4 JW |
1020 | WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); |
1021 | dbg_io_ops = NULL; | |
dc7d5527 JW |
1022 | |
1023 | spin_unlock(&kgdb_registration_lock); | |
1024 | ||
0f16996c | 1025 | pr_info("Unregistered I/O driver %s, debugger disabled\n", |
53197fc4 | 1026 | old_dbg_io_ops->name); |
dc7d5527 JW |
1027 | } |
1028 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); | |
1029 | ||
dcc78711 JW |
1030 | int dbg_io_get_char(void) |
1031 | { | |
1032 | int ret = dbg_io_ops->read_char(); | |
f5316b4a JW |
1033 | if (ret == NO_POLL_CHAR) |
1034 | return -1; | |
dcc78711 JW |
1035 | if (!dbg_kdb_mode) |
1036 | return ret; | |
1037 | if (ret == 127) | |
1038 | return 8; | |
1039 | return ret; | |
1040 | } | |
1041 | ||
dc7d5527 JW |
1042 | /** |
1043 | * kgdb_breakpoint - generate breakpoint exception | |
1044 | * | |
1045 | * This function will generate a breakpoint exception. It is used at the | |
1046 | * beginning of a program to sync up with a debugger and can be used | |
1047 | * otherwise as a quick means to stop program execution and "break" into | |
1048 | * the debugger. | |
1049 | */ | |
d498d4b4 | 1050 | noinline void kgdb_breakpoint(void) |
dc7d5527 | 1051 | { |
ae6bf53e | 1052 | atomic_inc(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1053 | wmb(); /* Sync point before breakpoint */ |
1054 | arch_kgdb_breakpoint(); | |
1055 | wmb(); /* Sync point after breakpoint */ | |
ae6bf53e | 1056 | atomic_dec(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1057 | } |
1058 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); | |
1059 | ||
1060 | static int __init opt_kgdb_wait(char *str) | |
1061 | { | |
1062 | kgdb_break_asap = 1; | |
1063 | ||
dcc78711 | 1064 | kdb_init(KDB_INIT_EARLY); |
dc7d5527 JW |
1065 | if (kgdb_io_module_registered) |
1066 | kgdb_initial_breakpoint(); | |
1067 | ||
1068 | return 0; | |
1069 | } | |
1070 | ||
1071 | early_param("kgdbwait", opt_kgdb_wait); |