1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Kernel Debug Core |
4 | * |
5 | * Maintainer: Jason Wessel <jason.wessel@windriver.com> |
6 | * |
7 | * Copyright (C) 2000-2001 VERITAS Software Corporation. |
8 | * Copyright (C) 2002-2004 Timesys Corporation |
9 | * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com> |
10 | * Copyright (C) 2004 Pavel Machek <pavel@ucw.cz> |
11 | * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> |
12 | * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. |
13 | * Copyright (C) 2005-2009 Wind River Systems, Inc. |
14 | * Copyright (C) 2007 MontaVista Software, Inc. |
15 | * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
16 | * |
17 | * Contributors at various stages not listed above: |
18 | * Jason Wessel ( jason.wessel@windriver.com ) |
19 | * George Anzinger <george@mvista.com> |
20 | * Anurekh Saxena (anurekh.saxena@timesys.com) |
21 | * Lake Stevens Instrument Division (Glenn Engel) |
22 | * Jim Kingdon, Cygnus Support. |
23 | * |
24 | * Original KGDB stub: David Grothe <dave@gcom.com>, |
25 | * Tigran Aivazian <tigran@sco.com> |
26 | */ |
27 | |
28 | #define pr_fmt(fmt) "KGDB: " fmt |
29 | |
30 | #include <linux/pid_namespace.h> |
31 | #include <linux/clocksource.h> |
32 | #include <linux/serial_core.h> |
33 | #include <linux/interrupt.h> |
34 | #include <linux/spinlock.h> |
35 | #include <linux/console.h> |
36 | #include <linux/threads.h> |
37 | #include <linux/uaccess.h> |
38 | #include <linux/kernel.h> |
39 | #include <linux/module.h> |
40 | #include <linux/ptrace.h> |
41 | #include <linux/string.h> |
42 | #include <linux/delay.h> |
43 | #include <linux/sched.h> |
44 | #include <linux/sysrq.h> |
45 | #include <linux/reboot.h> |
46 | #include <linux/init.h> |
47 | #include <linux/kgdb.h> |
48 | #include <linux/kdb.h> |
49 | #include <linux/nmi.h> |
50 | #include <linux/pid.h> |
51 | #include <linux/smp.h> |
52 | #include <linux/mm.h> |
53 | #include <linux/rcupdate.h> |
54 | #include <linux/irq.h> |
55 | #include <linux/security.h> |
56 | |
57 | #include <asm/cacheflush.h> |
58 | #include <asm/byteorder.h> |
59 | #include <linux/atomic.h> |
60 | |
61 | #include "debug_core.h" |
62 | |
63 | static int kgdb_break_asap; |
64 | |
65 | struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
66 | |
67 | /* kgdb_connected - Is a host GDB connected to us? */ |
68 | int kgdb_connected; |
69 | EXPORT_SYMBOL_GPL(kgdb_connected); |
70 | |
71 | /* All the KGDB handlers are installed */ |
72 | int kgdb_io_module_registered; |
73 | |
74 | /* Guard for recursive entry */ |
75 | static int exception_level; |
76 | |
77 | struct kgdb_io *dbg_io_ops; |
78 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
79 | |
80 | /* Action for the reboot notifier, a global allow kdb to change it */ |
81 | static int kgdbreboot; |
82 | /* kgdb console driver is loaded */ |
83 | static int kgdb_con_registered; |
84 | /* determine if kgdb console output should be used */ |
85 | static int kgdb_use_con; |
86 | /* Flag for alternate operations for early debugging */ |
87 | bool dbg_is_early = true; |
88 | /* Next cpu to become the master debug core */ |
89 | int dbg_switch_cpu; |
90 | |
91 | /* Use kdb or gdbserver mode */ |
92 | int dbg_kdb_mode = 1; |
93 | |
94 | module_param(kgdb_use_con, int, 0644); |
95 | module_param(kgdbreboot, int, 0644); |
96 | |
97 | /* |
98 | * Holds information about breakpoints in a kernel. These breakpoints are |
99 | * added and removed by gdb. |
100 | */ |
101 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { |
102 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } |
103 | }; |
104 | |
105 | /* |
106 | * The CPU# of the active CPU, or -1 if none: |
107 | */ |
108 | atomic_t kgdb_active = ATOMIC_INIT(-1); |
109 | EXPORT_SYMBOL_GPL(kgdb_active); |
110 | static DEFINE_RAW_SPINLOCK(dbg_master_lock); |
111 | static DEFINE_RAW_SPINLOCK(dbg_slave_lock); |
112 | |
113 | /* |
114 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early |
115 | * bootup code (which might not have percpu set up yet): |
116 | */ |
117 | static atomic_t masters_in_kgdb; |
118 | static atomic_t slaves_in_kgdb; |
119 | atomic_t kgdb_setting_breakpoint; |
120 | |
121 | struct task_struct *kgdb_usethread; |
122 | struct task_struct *kgdb_contthread; |
123 | |
124 | int kgdb_single_step; |
125 | static pid_t kgdb_sstep_pid; |
126 | |
127 | /* to keep track of the CPU which is doing the single stepping*/ |
128 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); |
129 | |
130 | /* |
131 | * If you are debugging a problem where roundup (the collection of |
132 | * all other CPUs) is a problem [this should be extremely rare], |
133 | * then use the nokgdbroundup option to avoid roundup. In that case |
134 | * the other CPUs might interfere with your debugging context, so |
135 | * use this with care: |
136 | */ |
137 | static int kgdb_do_roundup = 1; |
138 | |
139 | static int __init opt_nokgdbroundup(char *str) |
140 | { |
141 | kgdb_do_roundup = 0; |
142 | |
143 | return 0; |
144 | } |
145 | |
146 | early_param("nokgdbroundup" , opt_nokgdbroundup); |
147 | |
148 | /* |
149 | * Finally, some KGDB code :-) |
150 | */ |
151 | |
152 | /* |
153 | * Weak aliases for breakpoint management, |
154 | * can be overridden by architectures when needed: |
155 | */ |
156 | int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
157 | { |
158 | int err; |
159 | |
160 | err = copy_from_kernel_nofault(dst: bpt->saved_instr, src: (char *)bpt->bpt_addr, |
161 | BREAK_INSTR_SIZE); |
162 | if (err) |
163 | return err; |
164 | err = copy_to_kernel_nofault(dst: (char *)bpt->bpt_addr, |
165 | src: arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); |
166 | return err; |
167 | } |
168 | NOKPROBE_SYMBOL(kgdb_arch_set_breakpoint); |
169 | |
170 | int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
171 | { |
172 | return copy_to_kernel_nofault(dst: (char *)bpt->bpt_addr, |
173 | src: (char *)bpt->saved_instr, BREAK_INSTR_SIZE); |
174 | } |
175 | NOKPROBE_SYMBOL(kgdb_arch_remove_breakpoint); |
176 | |
177 | int __weak kgdb_validate_break_address(unsigned long addr) |
178 | { |
179 | struct kgdb_bkpt tmp; |
180 | int err; |
181 | |
182 | if (kgdb_within_blocklist(addr)) |
183 | return -EINVAL; |
184 | |
185 | /* Validate setting the breakpoint and then removing it. If the |
186 | * remove fails, the kernel needs to emit a bad message because we |
187 | * are deep trouble not being able to put things back the way we |
188 | * found them. |
189 | */ |
190 | tmp.bpt_addr = addr; |
191 | err = kgdb_arch_set_breakpoint(bpt: &tmp); |
192 | if (err) |
193 | return err; |
194 | err = kgdb_arch_remove_breakpoint(bpt: &tmp); |
195 | if (err) |
196 | pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n" , |
197 | addr); |
198 | return err; |
199 | } |
200 | |
201 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
202 | { |
203 | return instruction_pointer(regs); |
204 | } |
205 | NOKPROBE_SYMBOL(kgdb_arch_pc); |
206 | |
207 | int __weak kgdb_arch_init(void) |
208 | { |
209 | return 0; |
210 | } |
211 | |
212 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
213 | { |
214 | return 0; |
215 | } |
216 | NOKPROBE_SYMBOL(kgdb_skipexception); |
217 | |
218 | #ifdef CONFIG_SMP |
219 | |
220 | /* |
221 | * Default (weak) implementation for kgdb_roundup_cpus |
222 | */ |
223 | |
224 | void __weak kgdb_call_nmi_hook(void *ignored) |
225 | { |
226 | /* |
227 | * NOTE: get_irq_regs() is supposed to get the registers from |
228 | * before the IPI interrupt happened and so is supposed to |
229 | * show where the processor was. In some situations it's |
230 | * possible we might be called without an IPI, so it might be |
231 | * safer to figure out how to make kgdb_breakpoint() work |
232 | * properly here. |
233 | */ |
234 | kgdb_nmicallback(raw_smp_processor_id(), regs: get_irq_regs()); |
235 | } |
236 | NOKPROBE_SYMBOL(kgdb_call_nmi_hook); |
237 | |
238 | static DEFINE_PER_CPU(call_single_data_t, kgdb_roundup_csd) = |
239 | CSD_INIT(kgdb_call_nmi_hook, NULL); |
240 | |
241 | void __weak kgdb_roundup_cpus(void) |
242 | { |
243 | call_single_data_t *csd; |
244 | int this_cpu = raw_smp_processor_id(); |
245 | int cpu; |
246 | int ret; |
247 | |
248 | for_each_online_cpu(cpu) { |
249 | /* No need to roundup ourselves */ |
250 | if (cpu == this_cpu) |
251 | continue; |
252 | |
253 | csd = &per_cpu(kgdb_roundup_csd, cpu); |
254 | |
255 | /* |
256 | * If it didn't round up last time, don't try again |
257 | * since smp_call_function_single_async() will block. |
258 | * |
259 | * If rounding_up is false then we know that the |
260 | * previous call must have at least started and that |
261 | * means smp_call_function_single_async() won't block. |
262 | */ |
263 | if (kgdb_info[cpu].rounding_up) |
264 | continue; |
265 | kgdb_info[cpu].rounding_up = true; |
266 | |
267 | ret = smp_call_function_single_async(cpu, csd); |
268 | if (ret) |
269 | kgdb_info[cpu].rounding_up = false; |
270 | } |
271 | } |
272 | NOKPROBE_SYMBOL(kgdb_roundup_cpus); |
273 | |
274 | #endif |
275 | |
276 | /* |
277 | * Some architectures need cache flushes when we set/clear a |
278 | * breakpoint: |
279 | */ |
280 | static void kgdb_flush_swbreak_addr(unsigned long addr) |
281 | { |
282 | if (!CACHE_FLUSH_IS_SAFE) |
283 | return; |
284 | |
285 | /* Force flush instruction cache if it was outside the mm */ |
286 | flush_icache_range(start: addr, end: addr + BREAK_INSTR_SIZE); |
287 | } |
288 | NOKPROBE_SYMBOL(kgdb_flush_swbreak_addr); |
289 | |
290 | /* |
291 | * SW breakpoint management: |
292 | */ |
293 | int dbg_activate_sw_breakpoints(void) |
294 | { |
295 | int error; |
296 | int ret = 0; |
297 | int i; |
298 | |
299 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
300 | if (kgdb_break[i].state != BP_SET) |
301 | continue; |
302 | |
303 | error = kgdb_arch_set_breakpoint(bpt: &kgdb_break[i]); |
304 | if (error) { |
305 | ret = error; |
306 | pr_info("BP install failed: %lx\n" , |
307 | kgdb_break[i].bpt_addr); |
308 | continue; |
309 | } |
310 | |
311 | kgdb_flush_swbreak_addr(addr: kgdb_break[i].bpt_addr); |
312 | kgdb_break[i].state = BP_ACTIVE; |
313 | } |
314 | return ret; |
315 | } |
316 | NOKPROBE_SYMBOL(dbg_activate_sw_breakpoints); |
317 | |
318 | int dbg_set_sw_break(unsigned long addr) |
319 | { |
320 | int err = kgdb_validate_break_address(addr); |
321 | int breakno = -1; |
322 | int i; |
323 | |
324 | if (err) |
325 | return err; |
326 | |
327 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
328 | if ((kgdb_break[i].state == BP_SET) && |
329 | (kgdb_break[i].bpt_addr == addr)) |
330 | return -EEXIST; |
331 | } |
332 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
333 | if (kgdb_break[i].state == BP_REMOVED && |
334 | kgdb_break[i].bpt_addr == addr) { |
335 | breakno = i; |
336 | break; |
337 | } |
338 | } |
339 | |
340 | if (breakno == -1) { |
341 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
342 | if (kgdb_break[i].state == BP_UNDEFINED) { |
343 | breakno = i; |
344 | break; |
345 | } |
346 | } |
347 | } |
348 | |
349 | if (breakno == -1) |
350 | return -E2BIG; |
351 | |
352 | kgdb_break[breakno].state = BP_SET; |
353 | kgdb_break[breakno].type = BP_BREAKPOINT; |
354 | kgdb_break[breakno].bpt_addr = addr; |
355 | |
356 | return 0; |
357 | } |
358 | |
359 | int dbg_deactivate_sw_breakpoints(void) |
360 | { |
361 | int error; |
362 | int ret = 0; |
363 | int i; |
364 | |
365 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
366 | if (kgdb_break[i].state != BP_ACTIVE) |
367 | continue; |
368 | error = kgdb_arch_remove_breakpoint(bpt: &kgdb_break[i]); |
369 | if (error) { |
370 | pr_info("BP remove failed: %lx\n" , |
371 | kgdb_break[i].bpt_addr); |
372 | ret = error; |
373 | } |
374 | |
375 | kgdb_flush_swbreak_addr(addr: kgdb_break[i].bpt_addr); |
376 | kgdb_break[i].state = BP_SET; |
377 | } |
378 | return ret; |
379 | } |
380 | NOKPROBE_SYMBOL(dbg_deactivate_sw_breakpoints); |
381 | |
382 | int dbg_remove_sw_break(unsigned long addr) |
383 | { |
384 | int i; |
385 | |
386 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
387 | if ((kgdb_break[i].state == BP_SET) && |
388 | (kgdb_break[i].bpt_addr == addr)) { |
389 | kgdb_break[i].state = BP_REMOVED; |
390 | return 0; |
391 | } |
392 | } |
393 | return -ENOENT; |
394 | } |
395 | |
396 | int kgdb_isremovedbreak(unsigned long addr) |
397 | { |
398 | int i; |
399 | |
400 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
401 | if ((kgdb_break[i].state == BP_REMOVED) && |
402 | (kgdb_break[i].bpt_addr == addr)) |
403 | return 1; |
404 | } |
405 | return 0; |
406 | } |
407 | |
408 | int kgdb_has_hit_break(unsigned long addr) |
409 | { |
410 | int i; |
411 | |
412 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
413 | if (kgdb_break[i].state == BP_ACTIVE && |
414 | kgdb_break[i].bpt_addr == addr) |
415 | return 1; |
416 | } |
417 | return 0; |
418 | } |
419 | |
420 | int dbg_remove_all_break(void) |
421 | { |
422 | int error; |
423 | int i; |
424 | |
425 | /* Clear memory breakpoints. */ |
426 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
427 | if (kgdb_break[i].state != BP_ACTIVE) |
428 | goto setundefined; |
429 | error = kgdb_arch_remove_breakpoint(bpt: &kgdb_break[i]); |
430 | if (error) |
431 | pr_err("breakpoint remove failed: %lx\n" , |
432 | kgdb_break[i].bpt_addr); |
433 | setundefined: |
434 | kgdb_break[i].state = BP_UNDEFINED; |
435 | } |
436 | |
437 | /* Clear hardware breakpoints. */ |
438 | if (arch_kgdb_ops.remove_all_hw_break) |
439 | arch_kgdb_ops.remove_all_hw_break(); |
440 | |
441 | return 0; |
442 | } |
443 | |
444 | void kgdb_free_init_mem(void) |
445 | { |
446 | int i; |
447 | |
448 | /* Clear init memory breakpoints. */ |
449 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
450 | if (init_section_contains(virt: (void *)kgdb_break[i].bpt_addr, size: 0)) |
451 | kgdb_break[i].state = BP_UNDEFINED; |
452 | } |
453 | } |
454 | |
455 | #ifdef CONFIG_KGDB_KDB |
456 | void kdb_dump_stack_on_cpu(int cpu) |
457 | { |
458 | if (cpu == raw_smp_processor_id() || !IS_ENABLED(CONFIG_SMP)) { |
459 | dump_stack(); |
460 | return; |
461 | } |
462 | |
463 | if (!(kgdb_info[cpu].exception_state & DCPU_IS_SLAVE)) { |
464 | kdb_printf("ERROR: Task on cpu %d didn't stop in the debugger\n" , |
465 | cpu); |
466 | return; |
467 | } |
468 | |
469 | /* |
470 | * In general, architectures don't support dumping the stack of a |
471 | * "running" process that's not the current one. From the point of |
472 | * view of the Linux, kernel processes that are looping in the kgdb |
473 | * slave loop are still "running". There's also no API (that actually |
474 | * works across all architectures) that can do a stack crawl based |
475 | * on registers passed as a parameter. |
476 | * |
477 | * Solve this conundrum by asking slave CPUs to do the backtrace |
478 | * themselves. |
479 | */ |
480 | kgdb_info[cpu].exception_state |= DCPU_WANT_BT; |
481 | while (kgdb_info[cpu].exception_state & DCPU_WANT_BT) |
482 | cpu_relax(); |
483 | } |
484 | #endif |
485 | |
486 | /* |
487 | * Return true if there is a valid kgdb I/O module. Also if no |
488 | * debugger is attached a message can be printed to the console about |
489 | * waiting for the debugger to attach. |
490 | * |
491 | * The print_wait argument is only to be true when called from inside |
492 | * the core kgdb_handle_exception, because it will wait for the |
493 | * debugger to attach. |
494 | */ |
495 | static int kgdb_io_ready(int print_wait) |
496 | { |
497 | if (!dbg_io_ops) |
498 | return 0; |
499 | if (kgdb_connected) |
500 | return 1; |
501 | if (atomic_read(v: &kgdb_setting_breakpoint)) |
502 | return 1; |
503 | if (print_wait) { |
504 | #ifdef CONFIG_KGDB_KDB |
505 | if (!dbg_kdb_mode) |
506 | pr_crit("waiting... or $3#33 for KDB\n" ); |
507 | #else |
508 | pr_crit("Waiting for remote debugger\n" ); |
509 | #endif |
510 | } |
511 | return 1; |
512 | } |
513 | NOKPROBE_SYMBOL(kgdb_io_ready); |
514 | |
515 | static int kgdb_reenter_check(struct kgdb_state *ks) |
516 | { |
517 | unsigned long addr; |
518 | |
519 | if (atomic_read(v: &kgdb_active) != raw_smp_processor_id()) |
520 | return 0; |
521 | |
522 | /* Panic on recursive debugger calls: */ |
523 | exception_level++; |
524 | addr = kgdb_arch_pc(exception: ks->ex_vector, regs: ks->linux_regs); |
525 | dbg_deactivate_sw_breakpoints(); |
526 | |
527 | /* |
528 | * If the break point removed ok at the place exception |
529 | * occurred, try to recover and print a warning to the end |
530 | * user because the user planted a breakpoint in a place that |
531 | * KGDB needs in order to function. |
532 | */ |
533 | if (dbg_remove_sw_break(addr) == 0) { |
534 | exception_level = 0; |
535 | kgdb_skipexception(exception: ks->ex_vector, regs: ks->linux_regs); |
536 | dbg_activate_sw_breakpoints(); |
537 | pr_crit("re-enter error: breakpoint removed %lx\n" , addr); |
538 | WARN_ON_ONCE(1); |
539 | |
540 | return 1; |
541 | } |
542 | dbg_remove_all_break(); |
543 | kgdb_skipexception(exception: ks->ex_vector, regs: ks->linux_regs); |
544 | |
545 | if (exception_level > 1) { |
546 | dump_stack(); |
547 | kgdb_io_module_registered = false; |
548 | panic(fmt: "Recursive entry to debugger" ); |
549 | } |
550 | |
551 | pr_crit("re-enter exception: ALL breakpoints killed\n" ); |
552 | #ifdef CONFIG_KGDB_KDB |
553 | /* Allow kdb to debug itself one level */ |
554 | return 0; |
555 | #endif |
556 | dump_stack(); |
557 | panic(fmt: "Recursive entry to debugger" ); |
558 | |
559 | return 1; |
560 | } |
561 | NOKPROBE_SYMBOL(kgdb_reenter_check); |
562 | |
563 | static void dbg_touch_watchdogs(void) |
564 | { |
565 | touch_softlockup_watchdog_sync(); |
566 | clocksource_touch_watchdog(); |
567 | rcu_cpu_stall_reset(); |
568 | } |
569 | NOKPROBE_SYMBOL(dbg_touch_watchdogs); |
570 | |
571 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, |
572 | int exception_state) |
573 | { |
574 | unsigned long flags; |
575 | int sstep_tries = 100; |
576 | int error; |
577 | int cpu; |
578 | int trace_on = 0; |
579 | int online_cpus = num_online_cpus(); |
580 | u64 time_left; |
581 | |
582 | kgdb_info[ks->cpu].enter_kgdb++; |
583 | kgdb_info[ks->cpu].exception_state |= exception_state; |
584 | |
585 | if (exception_state == DCPU_WANT_MASTER) |
586 | atomic_inc(v: &masters_in_kgdb); |
587 | else |
588 | atomic_inc(v: &slaves_in_kgdb); |
589 | |
590 | if (arch_kgdb_ops.disable_hw_break) |
591 | arch_kgdb_ops.disable_hw_break(regs); |
592 | |
593 | acquirelock: |
594 | rcu_read_lock(); |
595 | /* |
596 | * Interrupts will be restored by the 'trap return' code, except when |
597 | * single stepping. |
598 | */ |
599 | local_irq_save(flags); |
600 | |
601 | cpu = ks->cpu; |
602 | kgdb_info[cpu].debuggerinfo = regs; |
603 | kgdb_info[cpu].task = current; |
604 | kgdb_info[cpu].ret_state = 0; |
605 | kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; |
606 | |
607 | /* Make sure the above info reaches the primary CPU */ |
608 | smp_mb(); |
609 | |
610 | if (exception_level == 1) { |
611 | if (raw_spin_trylock(&dbg_master_lock)) |
612 | atomic_xchg(v: &kgdb_active, new: cpu); |
613 | goto cpu_master_loop; |
614 | } |
615 | |
616 | /* |
617 | * CPU will loop if it is a slave or request to become a kgdb |
618 | * master cpu and acquire the kgdb_active lock: |
619 | */ |
620 | while (1) { |
621 | cpu_loop: |
622 | if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) { |
623 | kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER; |
624 | goto cpu_master_loop; |
625 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { |
626 | if (raw_spin_trylock(&dbg_master_lock)) { |
627 | atomic_xchg(v: &kgdb_active, new: cpu); |
628 | break; |
629 | } |
630 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_BT) { |
631 | dump_stack(); |
632 | kgdb_info[cpu].exception_state &= ~DCPU_WANT_BT; |
633 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
634 | if (!raw_spin_is_locked(&dbg_slave_lock)) |
635 | goto return_normal; |
636 | } else { |
637 | return_normal: |
638 | /* Return to normal operation by executing any |
639 | * hw breakpoint fixup. |
640 | */ |
641 | if (arch_kgdb_ops.correct_hw_break) |
642 | arch_kgdb_ops.correct_hw_break(); |
643 | if (trace_on) |
644 | tracing_on(); |
645 | kgdb_info[cpu].debuggerinfo = NULL; |
646 | kgdb_info[cpu].task = NULL; |
647 | kgdb_info[cpu].exception_state &= |
648 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); |
649 | kgdb_info[cpu].enter_kgdb--; |
650 | smp_mb__before_atomic(); |
651 | atomic_dec(v: &slaves_in_kgdb); |
652 | dbg_touch_watchdogs(); |
653 | local_irq_restore(flags); |
654 | rcu_read_unlock(); |
655 | return 0; |
656 | } |
657 | cpu_relax(); |
658 | } |
659 | |
660 | /* |
661 | * For single stepping, try to only enter on the processor |
662 | * that was single stepping. To guard against a deadlock, the |
663 | * kernel will only try for the value of sstep_tries before |
664 | * giving up and continuing on. |
665 | */ |
666 | if (atomic_read(v: &kgdb_cpu_doing_single_step) != -1 && |
667 | (kgdb_info[cpu].task && |
668 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { |
669 | atomic_set(v: &kgdb_active, i: -1); |
670 | raw_spin_unlock(&dbg_master_lock); |
671 | dbg_touch_watchdogs(); |
672 | local_irq_restore(flags); |
673 | rcu_read_unlock(); |
674 | |
675 | goto acquirelock; |
676 | } |
677 | |
678 | if (!kgdb_io_ready(print_wait: 1)) { |
679 | kgdb_info[cpu].ret_state = 1; |
680 | goto kgdb_restore; /* No I/O connection, resume the system */ |
681 | } |
682 | |
683 | /* |
684 | * Don't enter if we have hit a removed breakpoint. |
685 | */ |
686 | if (kgdb_skipexception(exception: ks->ex_vector, regs: ks->linux_regs)) |
687 | goto kgdb_restore; |
688 | |
689 | atomic_inc(v: &ignore_console_lock_warning); |
690 | |
691 | /* Call the I/O driver's pre_exception routine */ |
692 | if (dbg_io_ops->pre_exception) |
693 | dbg_io_ops->pre_exception(); |
694 | |
695 | /* |
696 | * Get the passive CPU lock which will hold all the non-primary |
697 | * CPU in a spin state while the debugger is active |
698 | */ |
699 | if (!kgdb_single_step) |
700 | raw_spin_lock(&dbg_slave_lock); |
701 | |
702 | #ifdef CONFIG_SMP |
703 | /* If send_ready set, slaves are already waiting */ |
704 | if (ks->send_ready) |
705 | atomic_set(v: ks->send_ready, i: 1); |
706 | |
707 | /* Signal the other CPUs to enter kgdb_wait() */ |
708 | else if ((!kgdb_single_step) && kgdb_do_roundup) |
709 | kgdb_roundup_cpus(); |
710 | #endif |
711 | |
712 | /* |
713 | * Wait for the other CPUs to be notified and be waiting for us: |
714 | */ |
715 | time_left = MSEC_PER_SEC; |
716 | while (kgdb_do_roundup && --time_left && |
717 | (atomic_read(v: &masters_in_kgdb) + atomic_read(v: &slaves_in_kgdb)) != |
718 | online_cpus) |
719 | udelay(1000); |
720 | if (!time_left) |
721 | pr_crit("Timed out waiting for secondary CPUs.\n" ); |
722 | |
723 | /* |
724 | * At this point the primary processor is completely |
725 | * in the debugger and all secondary CPUs are quiescent |
726 | */ |
727 | dbg_deactivate_sw_breakpoints(); |
728 | kgdb_single_step = 0; |
729 | kgdb_contthread = current; |
730 | exception_level = 0; |
731 | trace_on = tracing_is_on(); |
732 | if (trace_on) |
733 | tracing_off(); |
734 | |
735 | while (1) { |
736 | cpu_master_loop: |
737 | if (dbg_kdb_mode) { |
738 | kgdb_connected = 1; |
739 | error = kdb_stub(ks); |
740 | if (error == -1) |
741 | continue; |
742 | kgdb_connected = 0; |
743 | } else { |
744 | /* |
745 | * This is a brutal way to interfere with the debugger |
746 | * and prevent gdb being used to poke at kernel memory. |
747 | * This could cause trouble if lockdown is applied when |
748 | * there is already an active gdb session. For now the |
749 | * answer is simply "don't do that". Typically lockdown |
750 | * *will* be applied before the debug core gets started |
751 | * so only developers using kgdb for fairly advanced |
752 | * early kernel debug can be biten by this. Hopefully |
753 | * they are sophisticated enough to take care of |
754 | * themselves, especially with help from the lockdown |
755 | * message printed on the console! |
756 | */ |
757 | if (security_locked_down(what: LOCKDOWN_DBG_WRITE_KERNEL)) { |
758 | if (IS_ENABLED(CONFIG_KGDB_KDB)) { |
759 | /* Switch back to kdb if possible... */ |
760 | dbg_kdb_mode = 1; |
761 | continue; |
762 | } else { |
763 | /* ... otherwise just bail */ |
764 | break; |
765 | } |
766 | } |
767 | error = gdb_serial_stub(ks); |
768 | } |
769 | |
770 | if (error == DBG_PASS_EVENT) { |
771 | dbg_kdb_mode = !dbg_kdb_mode; |
772 | } else if (error == DBG_SWITCH_CPU_EVENT) { |
773 | kgdb_info[dbg_switch_cpu].exception_state |= |
774 | DCPU_NEXT_MASTER; |
775 | goto cpu_loop; |
776 | } else { |
777 | kgdb_info[cpu].ret_state = error; |
778 | break; |
779 | } |
780 | } |
781 | |
782 | dbg_activate_sw_breakpoints(); |
783 | |
784 | /* Call the I/O driver's post_exception routine */ |
785 | if (dbg_io_ops->post_exception) |
786 | dbg_io_ops->post_exception(); |
787 | |
788 | atomic_dec(v: &ignore_console_lock_warning); |
789 | |
790 | if (!kgdb_single_step) { |
791 | raw_spin_unlock(&dbg_slave_lock); |
792 | /* Wait till all the CPUs have quit from the debugger. */ |
793 | while (kgdb_do_roundup && atomic_read(v: &slaves_in_kgdb)) |
794 | cpu_relax(); |
795 | } |
796 | |
797 | kgdb_restore: |
798 | if (atomic_read(v: &kgdb_cpu_doing_single_step) != -1) { |
799 | int sstep_cpu = atomic_read(v: &kgdb_cpu_doing_single_step); |
800 | if (kgdb_info[sstep_cpu].task) |
801 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; |
802 | else |
803 | kgdb_sstep_pid = 0; |
804 | } |
805 | if (arch_kgdb_ops.correct_hw_break) |
806 | arch_kgdb_ops.correct_hw_break(); |
807 | if (trace_on) |
808 | tracing_on(); |
809 | |
810 | kgdb_info[cpu].debuggerinfo = NULL; |
811 | kgdb_info[cpu].task = NULL; |
812 | kgdb_info[cpu].exception_state &= |
813 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); |
814 | kgdb_info[cpu].enter_kgdb--; |
815 | smp_mb__before_atomic(); |
816 | atomic_dec(v: &masters_in_kgdb); |
817 | /* Free kgdb_active */ |
818 | atomic_set(v: &kgdb_active, i: -1); |
819 | raw_spin_unlock(&dbg_master_lock); |
820 | dbg_touch_watchdogs(); |
821 | local_irq_restore(flags); |
822 | rcu_read_unlock(); |
823 | |
824 | return kgdb_info[cpu].ret_state; |
825 | } |
826 | NOKPROBE_SYMBOL(kgdb_cpu_enter); |
827 | |
828 | /* |
829 | * kgdb_handle_exception() - main entry point from a kernel exception |
830 | * |
831 | * Locking hierarchy: |
832 | * interface locks, if any (begin_session) |
833 | * kgdb lock (kgdb_active) |
834 | */ |
835 | int |
836 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) |
837 | { |
838 | struct kgdb_state kgdb_var; |
839 | struct kgdb_state *ks = &kgdb_var; |
840 | int ret = 0; |
841 | |
842 | if (arch_kgdb_ops.enable_nmi) |
843 | arch_kgdb_ops.enable_nmi(0); |
844 | /* |
845 | * Avoid entering the debugger if we were triggered due to an oops |
846 | * but panic_timeout indicates the system should automatically |
847 | * reboot on panic. We don't want to get stuck waiting for input |
848 | * on such systems, especially if its "just" an oops. |
849 | */ |
850 | if (signo != SIGTRAP && panic_timeout) |
851 | return 1; |
852 | |
853 | memset(ks, 0, sizeof(struct kgdb_state)); |
854 | ks->cpu = raw_smp_processor_id(); |
855 | ks->ex_vector = evector; |
856 | ks->signo = signo; |
857 | ks->err_code = ecode; |
858 | ks->linux_regs = regs; |
859 | |
860 | if (kgdb_reenter_check(ks)) |
861 | goto out; /* Ouch, double exception ! */ |
862 | if (kgdb_info[ks->cpu].enter_kgdb != 0) |
863 | goto out; |
864 | |
865 | ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
866 | out: |
867 | if (arch_kgdb_ops.enable_nmi) |
868 | arch_kgdb_ops.enable_nmi(1); |
869 | return ret; |
870 | } |
871 | NOKPROBE_SYMBOL(kgdb_handle_exception); |
872 | |
873 | /* |
874 | * GDB places a breakpoint at this function to know dynamically loaded objects. |
875 | */ |
876 | static int module_event(struct notifier_block *self, unsigned long val, |
877 | void *data) |
878 | { |
879 | return 0; |
880 | } |
881 | |
882 | static struct notifier_block dbg_module_load_nb = { |
883 | .notifier_call = module_event, |
884 | }; |
885 | |
886 | int kgdb_nmicallback(int cpu, void *regs) |
887 | { |
888 | #ifdef CONFIG_SMP |
889 | struct kgdb_state kgdb_var; |
890 | struct kgdb_state *ks = &kgdb_var; |
891 | |
892 | kgdb_info[cpu].rounding_up = false; |
893 | |
894 | memset(ks, 0, sizeof(struct kgdb_state)); |
895 | ks->cpu = cpu; |
896 | ks->linux_regs = regs; |
897 | |
898 | if (kgdb_info[ks->cpu].enter_kgdb == 0 && |
899 | raw_spin_is_locked(&dbg_master_lock)) { |
900 | kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); |
901 | return 0; |
902 | } |
903 | #endif |
904 | return 1; |
905 | } |
906 | NOKPROBE_SYMBOL(kgdb_nmicallback); |
907 | |
908 | int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, |
909 | atomic_t *send_ready) |
910 | { |
911 | #ifdef CONFIG_SMP |
912 | if (!kgdb_io_ready(print_wait: 0) || !send_ready) |
913 | return 1; |
914 | |
915 | if (kgdb_info[cpu].enter_kgdb == 0) { |
916 | struct kgdb_state kgdb_var; |
917 | struct kgdb_state *ks = &kgdb_var; |
918 | |
919 | memset(ks, 0, sizeof(struct kgdb_state)); |
920 | ks->cpu = cpu; |
921 | ks->ex_vector = trapnr; |
922 | ks->signo = SIGTRAP; |
923 | ks->err_code = err_code; |
924 | ks->linux_regs = regs; |
925 | ks->send_ready = send_ready; |
926 | kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
927 | return 0; |
928 | } |
929 | #endif |
930 | return 1; |
931 | } |
932 | NOKPROBE_SYMBOL(kgdb_nmicallin); |
933 | |
934 | static void kgdb_console_write(struct console *co, const char *s, |
935 | unsigned count) |
936 | { |
937 | unsigned long flags; |
938 | |
939 | /* If we're debugging, or KGDB has not connected, don't try |
940 | * and print. */ |
941 | if (!kgdb_connected || atomic_read(v: &kgdb_active) != -1 || dbg_kdb_mode) |
942 | return; |
943 | |
944 | local_irq_save(flags); |
945 | gdbstub_msg_write(s, len: count); |
946 | local_irq_restore(flags); |
947 | } |
948 | |
949 | static struct console kgdbcons = { |
950 | .name = "kgdb" , |
951 | .write = kgdb_console_write, |
952 | .flags = CON_PRINTBUFFER | CON_ENABLED, |
953 | .index = -1, |
954 | }; |
955 | |
956 | static int __init opt_kgdb_con(char *str) |
957 | { |
958 | kgdb_use_con = 1; |
959 | |
960 | if (kgdb_io_module_registered && !kgdb_con_registered) { |
961 | register_console(&kgdbcons); |
962 | kgdb_con_registered = 1; |
963 | } |
964 | |
965 | return 0; |
966 | } |
967 | |
968 | early_param("kgdbcon" , opt_kgdb_con); |
969 | |
970 | #ifdef CONFIG_MAGIC_SYSRQ |
971 | static void sysrq_handle_dbg(u8 key) |
972 | { |
973 | if (!dbg_io_ops) { |
974 | pr_crit("ERROR: No KGDB I/O module available\n" ); |
975 | return; |
976 | } |
977 | if (!kgdb_connected) { |
978 | #ifdef CONFIG_KGDB_KDB |
979 | if (!dbg_kdb_mode) |
980 | pr_crit("KGDB or $3#33 for KDB\n" ); |
981 | #else |
982 | pr_crit("Entering KGDB\n" ); |
983 | #endif |
984 | } |
985 | |
986 | kgdb_breakpoint(); |
987 | } |
988 | |
989 | static const struct sysrq_key_op sysrq_dbg_op = { |
990 | .handler = sysrq_handle_dbg, |
991 | .help_msg = "debug(g)" , |
992 | .action_msg = "DEBUG" , |
993 | }; |
994 | #endif |
995 | |
996 | void kgdb_panic(const char *msg) |
997 | { |
998 | if (!kgdb_io_module_registered) |
999 | return; |
1000 | |
1001 | /* |
1002 | * We don't want to get stuck waiting for input from user if |
1003 | * "panic_timeout" indicates the system should automatically |
1004 | * reboot on panic. |
1005 | */ |
1006 | if (panic_timeout) |
1007 | return; |
1008 | |
1009 | debug_locks_off(); |
1010 | console_flush_on_panic(mode: CONSOLE_FLUSH_PENDING); |
1011 | |
1012 | if (dbg_kdb_mode) |
1013 | kdb_printf("PANIC: %s\n" , msg); |
1014 | |
1015 | kgdb_breakpoint(); |
1016 | } |
1017 | |
1018 | static void kgdb_initial_breakpoint(void) |
1019 | { |
1020 | kgdb_break_asap = 0; |
1021 | |
1022 | pr_crit("Waiting for connection from remote gdb...\n" ); |
1023 | kgdb_breakpoint(); |
1024 | } |
1025 | |
1026 | void __weak kgdb_arch_late(void) |
1027 | { |
1028 | } |
1029 | |
1030 | void __init dbg_late_init(void) |
1031 | { |
1032 | dbg_is_early = false; |
1033 | if (kgdb_io_module_registered) |
1034 | kgdb_arch_late(); |
1035 | kdb_init(level: KDB_INIT_FULL); |
1036 | |
1037 | if (kgdb_io_module_registered && kgdb_break_asap) |
1038 | kgdb_initial_breakpoint(); |
1039 | } |
1040 | |
1041 | static int |
1042 | dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x) |
1043 | { |
1044 | /* |
1045 | * Take the following action on reboot notify depending on value: |
1046 | * 1 == Enter debugger |
1047 | * 0 == [the default] detach debug client |
1048 | * -1 == Do nothing... and use this until the board resets |
1049 | */ |
1050 | switch (kgdbreboot) { |
1051 | case 1: |
1052 | kgdb_breakpoint(); |
1053 | goto done; |
1054 | case -1: |
1055 | goto done; |
1056 | } |
1057 | if (!dbg_kdb_mode) |
1058 | gdbstub_exit(status: code); |
1059 | done: |
1060 | return NOTIFY_DONE; |
1061 | } |
1062 | |
1063 | static struct notifier_block dbg_reboot_notifier = { |
1064 | .notifier_call = dbg_notify_reboot, |
1065 | .next = NULL, |
1066 | .priority = INT_MAX, |
1067 | }; |
1068 | |
1069 | static void kgdb_register_callbacks(void) |
1070 | { |
1071 | if (!kgdb_io_module_registered) { |
1072 | kgdb_io_module_registered = 1; |
1073 | kgdb_arch_init(); |
1074 | if (!dbg_is_early) |
1075 | kgdb_arch_late(); |
1076 | register_module_notifier(nb: &dbg_module_load_nb); |
1077 | register_reboot_notifier(&dbg_reboot_notifier); |
1078 | #ifdef CONFIG_MAGIC_SYSRQ |
1079 | register_sysrq_key(key: 'g', op: &sysrq_dbg_op); |
1080 | #endif |
1081 | if (kgdb_use_con && !kgdb_con_registered) { |
1082 | register_console(&kgdbcons); |
1083 | kgdb_con_registered = 1; |
1084 | } |
1085 | } |
1086 | } |
1087 | |
1088 | static void kgdb_unregister_callbacks(void) |
1089 | { |
1090 | /* |
1091 | * When this routine is called KGDB should unregister from |
1092 | * handlers and clean up, making sure it is not handling any |
1093 | * break exceptions at the time. |
1094 | */ |
1095 | if (kgdb_io_module_registered) { |
1096 | kgdb_io_module_registered = 0; |
1097 | unregister_reboot_notifier(&dbg_reboot_notifier); |
1098 | unregister_module_notifier(nb: &dbg_module_load_nb); |
1099 | kgdb_arch_exit(); |
1100 | #ifdef CONFIG_MAGIC_SYSRQ |
1101 | unregister_sysrq_key(key: 'g', op: &sysrq_dbg_op); |
1102 | #endif |
1103 | if (kgdb_con_registered) { |
1104 | unregister_console(&kgdbcons); |
1105 | kgdb_con_registered = 0; |
1106 | } |
1107 | } |
1108 | } |
1109 | |
1110 | /** |
1111 | * kgdb_register_io_module - register KGDB IO module |
1112 | * @new_dbg_io_ops: the io ops vector |
1113 | * |
1114 | * Register it with the KGDB core. |
1115 | */ |
1116 | int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
1117 | { |
1118 | struct kgdb_io *old_dbg_io_ops; |
1119 | int err; |
1120 | |
1121 | spin_lock(lock: &kgdb_registration_lock); |
1122 | |
1123 | old_dbg_io_ops = dbg_io_ops; |
1124 | if (old_dbg_io_ops) { |
1125 | if (!old_dbg_io_ops->deinit) { |
1126 | spin_unlock(lock: &kgdb_registration_lock); |
1127 | |
1128 | pr_err("KGDB I/O driver %s can't replace %s.\n" , |
1129 | new_dbg_io_ops->name, old_dbg_io_ops->name); |
1130 | return -EBUSY; |
1131 | } |
1132 | pr_info("Replacing I/O driver %s with %s\n" , |
1133 | old_dbg_io_ops->name, new_dbg_io_ops->name); |
1134 | } |
1135 | |
1136 | if (new_dbg_io_ops->init) { |
1137 | err = new_dbg_io_ops->init(); |
1138 | if (err) { |
1139 | spin_unlock(lock: &kgdb_registration_lock); |
1140 | return err; |
1141 | } |
1142 | } |
1143 | |
1144 | dbg_io_ops = new_dbg_io_ops; |
1145 | |
1146 | spin_unlock(lock: &kgdb_registration_lock); |
1147 | |
1148 | if (old_dbg_io_ops) { |
1149 | old_dbg_io_ops->deinit(); |
1150 | return 0; |
1151 | } |
1152 | |
1153 | pr_info("Registered I/O driver %s\n" , new_dbg_io_ops->name); |
1154 | |
1155 | /* Arm KGDB now. */ |
1156 | kgdb_register_callbacks(); |
1157 | |
1158 | if (kgdb_break_asap && |
1159 | (!dbg_is_early || IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG))) |
1160 | kgdb_initial_breakpoint(); |
1161 | |
1162 | return 0; |
1163 | } |
1164 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); |
1165 | |
1166 | /** |
1167 | * kgdb_unregister_io_module - unregister KGDB IO module |
1168 | * @old_dbg_io_ops: the io ops vector |
1169 | * |
1170 | * Unregister it with the KGDB core. |
1171 | */ |
1172 | void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
1173 | { |
1174 | BUG_ON(kgdb_connected); |
1175 | |
1176 | /* |
1177 | * KGDB is no longer able to communicate out, so |
1178 | * unregister our callbacks and reset state. |
1179 | */ |
1180 | kgdb_unregister_callbacks(); |
1181 | |
1182 | spin_lock(lock: &kgdb_registration_lock); |
1183 | |
1184 | WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); |
1185 | dbg_io_ops = NULL; |
1186 | |
1187 | spin_unlock(lock: &kgdb_registration_lock); |
1188 | |
1189 | if (old_dbg_io_ops->deinit) |
1190 | old_dbg_io_ops->deinit(); |
1191 | |
1192 | pr_info("Unregistered I/O driver %s, debugger disabled\n" , |
1193 | old_dbg_io_ops->name); |
1194 | } |
1195 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); |
1196 | |
1197 | int dbg_io_get_char(void) |
1198 | { |
1199 | int ret = dbg_io_ops->read_char(); |
1200 | if (ret == NO_POLL_CHAR) |
1201 | return -1; |
1202 | if (!dbg_kdb_mode) |
1203 | return ret; |
1204 | if (ret == 127) |
1205 | return 8; |
1206 | return ret; |
1207 | } |
1208 | |
1209 | /** |
1210 | * kgdb_breakpoint - generate breakpoint exception |
1211 | * |
1212 | * This function will generate a breakpoint exception. It is used at the |
1213 | * beginning of a program to sync up with a debugger and can be used |
1214 | * otherwise as a quick means to stop program execution and "break" into |
1215 | * the debugger. |
1216 | */ |
1217 | noinline void kgdb_breakpoint(void) |
1218 | { |
1219 | atomic_inc(v: &kgdb_setting_breakpoint); |
1220 | wmb(); /* Sync point before breakpoint */ |
1221 | arch_kgdb_breakpoint(); |
1222 | wmb(); /* Sync point after breakpoint */ |
1223 | atomic_dec(v: &kgdb_setting_breakpoint); |
1224 | } |
1225 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); |
1226 | |
1227 | static int __init opt_kgdb_wait(char *str) |
1228 | { |
1229 | kgdb_break_asap = 1; |
1230 | |
1231 | kdb_init(level: KDB_INIT_EARLY); |
1232 | if (kgdb_io_module_registered && |
1233 | IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG)) |
1234 | kgdb_initial_breakpoint(); |
1235 | |
1236 | return 0; |
1237 | } |
1238 | |
1239 | early_param("kgdbwait" , opt_kgdb_wait); |
1240 | |