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> |
38b8d208 | 52 | #include <linux/nmi.h> |
dc7d5527 JW |
53 | #include <linux/pid.h> |
54 | #include <linux/smp.h> | |
55 | #include <linux/mm.h> | |
615d6e87 | 56 | #include <linux/vmacache.h> |
fb70b588 | 57 | #include <linux/rcupdate.h> |
3cd99ac3 | 58 | #include <linux/irq.h> |
dc7d5527 JW |
59 | |
60 | #include <asm/cacheflush.h> | |
61 | #include <asm/byteorder.h> | |
60063497 | 62 | #include <linux/atomic.h> |
dc7d5527 | 63 | |
53197fc4 | 64 | #include "debug_core.h" |
dc7d5527 | 65 | |
53197fc4 | 66 | static int kgdb_break_asap; |
62fae312 | 67 | |
53197fc4 | 68 | struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
dc7d5527 JW |
69 | |
70 | /** | |
71 | * kgdb_connected - Is a host GDB connected to us? | |
72 | */ | |
73 | int kgdb_connected; | |
74 | EXPORT_SYMBOL_GPL(kgdb_connected); | |
75 | ||
76 | /* All the KGDB handlers are installed */ | |
f503b5ae | 77 | int kgdb_io_module_registered; |
dc7d5527 JW |
78 | |
79 | /* Guard for recursive entry */ | |
80 | static int exception_level; | |
81 | ||
53197fc4 | 82 | struct kgdb_io *dbg_io_ops; |
dc7d5527 JW |
83 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
84 | ||
bec4d62e JW |
85 | /* Action for the reboot notifiter, a global allow kdb to change it */ |
86 | static int kgdbreboot; | |
dc7d5527 JW |
87 | /* kgdb console driver is loaded */ |
88 | static int kgdb_con_registered; | |
89 | /* determine if kgdb console output should be used */ | |
90 | static int kgdb_use_con; | |
0b4b3827 JW |
91 | /* Flag for alternate operations for early debugging */ |
92 | bool dbg_is_early = true; | |
dcc78711 JW |
93 | /* Next cpu to become the master debug core */ |
94 | int dbg_switch_cpu; | |
95 | ||
96 | /* Use kdb or gdbserver mode */ | |
a0de055c | 97 | int dbg_kdb_mode = 1; |
dc7d5527 JW |
98 | |
99 | static int __init opt_kgdb_con(char *str) | |
100 | { | |
101 | kgdb_use_con = 1; | |
102 | return 0; | |
103 | } | |
104 | ||
105 | early_param("kgdbcon", opt_kgdb_con); | |
106 | ||
107 | module_param(kgdb_use_con, int, 0644); | |
bec4d62e | 108 | module_param(kgdbreboot, int, 0644); |
dc7d5527 JW |
109 | |
110 | /* | |
111 | * Holds information about breakpoints in a kernel. These breakpoints are | |
112 | * added and removed by gdb. | |
113 | */ | |
114 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { | |
115 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } | |
116 | }; | |
117 | ||
118 | /* | |
119 | * The CPU# of the active CPU, or -1 if none: | |
120 | */ | |
121 | atomic_t kgdb_active = ATOMIC_INIT(-1); | |
dcc78711 | 122 | EXPORT_SYMBOL_GPL(kgdb_active); |
dfee3a7b JW |
123 | static DEFINE_RAW_SPINLOCK(dbg_master_lock); |
124 | static DEFINE_RAW_SPINLOCK(dbg_slave_lock); | |
dc7d5527 JW |
125 | |
126 | /* | |
127 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early | |
128 | * bootup code (which might not have percpu set up yet): | |
129 | */ | |
dfee3a7b JW |
130 | static atomic_t masters_in_kgdb; |
131 | static atomic_t slaves_in_kgdb; | |
1cee5e35 | 132 | static atomic_t kgdb_break_tasklet_var; |
dc7d5527 JW |
133 | atomic_t kgdb_setting_breakpoint; |
134 | ||
135 | struct task_struct *kgdb_usethread; | |
136 | struct task_struct *kgdb_contthread; | |
137 | ||
138 | int kgdb_single_step; | |
53197fc4 | 139 | static pid_t kgdb_sstep_pid; |
dc7d5527 JW |
140 | |
141 | /* to keep track of the CPU which is doing the single stepping*/ | |
142 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); | |
143 | ||
144 | /* | |
145 | * If you are debugging a problem where roundup (the collection of | |
146 | * all other CPUs) is a problem [this should be extremely rare], | |
147 | * then use the nokgdbroundup option to avoid roundup. In that case | |
148 | * the other CPUs might interfere with your debugging context, so | |
149 | * use this with care: | |
150 | */ | |
688b744d | 151 | static int kgdb_do_roundup = 1; |
dc7d5527 JW |
152 | |
153 | static int __init opt_nokgdbroundup(char *str) | |
154 | { | |
155 | kgdb_do_roundup = 0; | |
156 | ||
157 | return 0; | |
158 | } | |
159 | ||
160 | early_param("nokgdbroundup", opt_nokgdbroundup); | |
161 | ||
162 | /* | |
163 | * Finally, some KGDB code :-) | |
164 | */ | |
165 | ||
166 | /* | |
167 | * Weak aliases for breakpoint management, | |
168 | * can be overriden by architectures when needed: | |
169 | */ | |
98b54aa1 | 170 | int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 JW |
171 | { |
172 | int err; | |
173 | ||
98b54aa1 JW |
174 | err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, |
175 | BREAK_INSTR_SIZE); | |
dc7d5527 JW |
176 | if (err) |
177 | return err; | |
98b54aa1 JW |
178 | err = probe_kernel_write((char *)bpt->bpt_addr, |
179 | arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); | |
180 | return err; | |
dc7d5527 JW |
181 | } |
182 | ||
98b54aa1 | 183 | int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 | 184 | { |
98b54aa1 JW |
185 | return probe_kernel_write((char *)bpt->bpt_addr, |
186 | (char *)bpt->saved_instr, BREAK_INSTR_SIZE); | |
dc7d5527 JW |
187 | } |
188 | ||
a9b60bf4 JW |
189 | int __weak kgdb_validate_break_address(unsigned long addr) |
190 | { | |
98b54aa1 | 191 | struct kgdb_bkpt tmp; |
a9b60bf4 | 192 | int err; |
98b54aa1 | 193 | /* Validate setting the breakpoint and then removing it. If the |
a9b60bf4 JW |
194 | * remove fails, the kernel needs to emit a bad message because we |
195 | * are deep trouble not being able to put things back the way we | |
196 | * found them. | |
197 | */ | |
98b54aa1 JW |
198 | tmp.bpt_addr = addr; |
199 | err = kgdb_arch_set_breakpoint(&tmp); | |
a9b60bf4 JW |
200 | if (err) |
201 | return err; | |
98b54aa1 | 202 | err = kgdb_arch_remove_breakpoint(&tmp); |
a9b60bf4 | 203 | if (err) |
0f16996c FF |
204 | pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n", |
205 | addr); | |
a9b60bf4 JW |
206 | return err; |
207 | } | |
208 | ||
dc7d5527 JW |
209 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
210 | { | |
211 | return instruction_pointer(regs); | |
212 | } | |
213 | ||
214 | int __weak kgdb_arch_init(void) | |
215 | { | |
216 | return 0; | |
217 | } | |
218 | ||
b4b8ac52 JW |
219 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
220 | { | |
221 | return 0; | |
222 | } | |
223 | ||
3cd99ac3 DA |
224 | #ifdef CONFIG_SMP |
225 | ||
226 | /* | |
227 | * Default (weak) implementation for kgdb_roundup_cpus | |
228 | */ | |
229 | ||
230 | static DEFINE_PER_CPU(call_single_data_t, kgdb_roundup_csd); | |
231 | ||
232 | void __weak kgdb_call_nmi_hook(void *ignored) | |
233 | { | |
234 | /* | |
235 | * NOTE: get_irq_regs() is supposed to get the registers from | |
236 | * before the IPI interrupt happened and so is supposed to | |
237 | * show where the processor was. In some situations it's | |
238 | * possible we might be called without an IPI, so it might be | |
239 | * safer to figure out how to make kgdb_breakpoint() work | |
240 | * properly here. | |
241 | */ | |
242 | kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); | |
243 | } | |
244 | ||
245 | void __weak kgdb_roundup_cpus(void) | |
246 | { | |
247 | call_single_data_t *csd; | |
248 | int this_cpu = raw_smp_processor_id(); | |
249 | int cpu; | |
87b09592 | 250 | int ret; |
3cd99ac3 DA |
251 | |
252 | for_each_online_cpu(cpu) { | |
253 | /* No need to roundup ourselves */ | |
254 | if (cpu == this_cpu) | |
255 | continue; | |
256 | ||
257 | csd = &per_cpu(kgdb_roundup_csd, cpu); | |
87b09592 DA |
258 | |
259 | /* | |
260 | * If it didn't round up last time, don't try again | |
261 | * since smp_call_function_single_async() will block. | |
262 | * | |
263 | * If rounding_up is false then we know that the | |
264 | * previous call must have at least started and that | |
265 | * means smp_call_function_single_async() won't block. | |
266 | */ | |
267 | if (kgdb_info[cpu].rounding_up) | |
268 | continue; | |
269 | kgdb_info[cpu].rounding_up = true; | |
270 | ||
3cd99ac3 | 271 | csd->func = kgdb_call_nmi_hook; |
87b09592 DA |
272 | ret = smp_call_function_single_async(cpu, csd); |
273 | if (ret) | |
274 | kgdb_info[cpu].rounding_up = false; | |
3cd99ac3 DA |
275 | } |
276 | } | |
277 | ||
278 | #endif | |
279 | ||
dc7d5527 JW |
280 | /* |
281 | * Some architectures need cache flushes when we set/clear a | |
282 | * breakpoint: | |
283 | */ | |
284 | static void kgdb_flush_swbreak_addr(unsigned long addr) | |
285 | { | |
286 | if (!CACHE_FLUSH_IS_SAFE) | |
287 | return; | |
288 | ||
615d6e87 DB |
289 | if (current->mm) { |
290 | int i; | |
291 | ||
292 | for (i = 0; i < VMACACHE_SIZE; i++) { | |
314ff785 | 293 | if (!current->vmacache.vmas[i]) |
615d6e87 | 294 | continue; |
314ff785 | 295 | flush_cache_range(current->vmacache.vmas[i], |
615d6e87 DB |
296 | addr, addr + BREAK_INSTR_SIZE); |
297 | } | |
dc7d5527 | 298 | } |
615d6e87 | 299 | |
1a9a3e76 JW |
300 | /* Force flush instruction cache if it was outside the mm */ |
301 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); | |
dc7d5527 JW |
302 | } |
303 | ||
304 | /* | |
305 | * SW breakpoint management: | |
306 | */ | |
53197fc4 | 307 | int dbg_activate_sw_breakpoints(void) |
dc7d5527 | 308 | { |
7f8b7ed6 JW |
309 | int error; |
310 | int ret = 0; | |
dc7d5527 JW |
311 | int i; |
312 | ||
313 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
314 | if (kgdb_break[i].state != BP_SET) | |
315 | continue; | |
316 | ||
98b54aa1 | 317 | error = kgdb_arch_set_breakpoint(&kgdb_break[i]); |
7f8b7ed6 JW |
318 | if (error) { |
319 | ret = error; | |
0f16996c FF |
320 | pr_info("BP install failed: %lx\n", |
321 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
322 | continue; |
323 | } | |
dc7d5527 | 324 | |
98b54aa1 | 325 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
326 | kgdb_break[i].state = BP_ACTIVE; |
327 | } | |
7f8b7ed6 | 328 | return ret; |
dc7d5527 JW |
329 | } |
330 | ||
53197fc4 | 331 | int dbg_set_sw_break(unsigned long addr) |
dc7d5527 JW |
332 | { |
333 | int err = kgdb_validate_break_address(addr); | |
334 | int breakno = -1; | |
335 | int i; | |
336 | ||
337 | if (err) | |
338 | return err; | |
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 | return -EEXIST; | |
344 | } | |
345 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
346 | if (kgdb_break[i].state == BP_REMOVED && | |
347 | kgdb_break[i].bpt_addr == addr) { | |
348 | breakno = i; | |
349 | break; | |
350 | } | |
351 | } | |
352 | ||
353 | if (breakno == -1) { | |
354 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
355 | if (kgdb_break[i].state == BP_UNDEFINED) { | |
356 | breakno = i; | |
357 | break; | |
358 | } | |
359 | } | |
360 | } | |
361 | ||
362 | if (breakno == -1) | |
363 | return -E2BIG; | |
364 | ||
365 | kgdb_break[breakno].state = BP_SET; | |
366 | kgdb_break[breakno].type = BP_BREAKPOINT; | |
367 | kgdb_break[breakno].bpt_addr = addr; | |
368 | ||
369 | return 0; | |
370 | } | |
371 | ||
dcc78711 | 372 | int dbg_deactivate_sw_breakpoints(void) |
dc7d5527 | 373 | { |
7f8b7ed6 JW |
374 | int error; |
375 | int ret = 0; | |
dc7d5527 JW |
376 | int i; |
377 | ||
378 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
379 | if (kgdb_break[i].state != BP_ACTIVE) | |
380 | continue; | |
98b54aa1 | 381 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
7f8b7ed6 | 382 | if (error) { |
0f16996c FF |
383 | pr_info("BP remove failed: %lx\n", |
384 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
385 | ret = error; |
386 | } | |
dc7d5527 | 387 | |
98b54aa1 | 388 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
389 | kgdb_break[i].state = BP_SET; |
390 | } | |
7f8b7ed6 | 391 | return ret; |
dc7d5527 JW |
392 | } |
393 | ||
53197fc4 | 394 | int dbg_remove_sw_break(unsigned long addr) |
dc7d5527 JW |
395 | { |
396 | int i; | |
397 | ||
398 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
399 | if ((kgdb_break[i].state == BP_SET) && | |
400 | (kgdb_break[i].bpt_addr == addr)) { | |
401 | kgdb_break[i].state = BP_REMOVED; | |
402 | return 0; | |
403 | } | |
404 | } | |
405 | return -ENOENT; | |
406 | } | |
407 | ||
408 | int kgdb_isremovedbreak(unsigned long addr) | |
409 | { | |
410 | int i; | |
411 | ||
412 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
413 | if ((kgdb_break[i].state == BP_REMOVED) && | |
414 | (kgdb_break[i].bpt_addr == addr)) | |
415 | return 1; | |
416 | } | |
417 | return 0; | |
418 | } | |
419 | ||
53197fc4 | 420 | int dbg_remove_all_break(void) |
dc7d5527 | 421 | { |
dc7d5527 JW |
422 | int error; |
423 | int i; | |
424 | ||
425 | /* Clear memory breakpoints. */ | |
426 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
737a460f JW |
427 | if (kgdb_break[i].state != BP_ACTIVE) |
428 | goto setundefined; | |
98b54aa1 | 429 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
dc7d5527 | 430 | if (error) |
0f16996c | 431 | pr_err("breakpoint remove failed: %lx\n", |
98b54aa1 | 432 | kgdb_break[i].bpt_addr); |
737a460f JW |
433 | setundefined: |
434 | kgdb_break[i].state = BP_UNDEFINED; | |
dc7d5527 JW |
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 | ||
2277b492 DA |
444 | #ifdef CONFIG_KGDB_KDB |
445 | void kdb_dump_stack_on_cpu(int cpu) | |
446 | { | |
d07ce4e3 | 447 | if (cpu == raw_smp_processor_id() || !IS_ENABLED(CONFIG_SMP)) { |
2277b492 DA |
448 | dump_stack(); |
449 | return; | |
450 | } | |
451 | ||
452 | if (!(kgdb_info[cpu].exception_state & DCPU_IS_SLAVE)) { | |
453 | kdb_printf("ERROR: Task on cpu %d didn't stop in the debugger\n", | |
454 | cpu); | |
455 | return; | |
456 | } | |
457 | ||
458 | /* | |
459 | * In general, architectures don't support dumping the stack of a | |
460 | * "running" process that's not the current one. From the point of | |
461 | * view of the Linux, kernel processes that are looping in the kgdb | |
462 | * slave loop are still "running". There's also no API (that actually | |
463 | * works across all architectures) that can do a stack crawl based | |
464 | * on registers passed as a parameter. | |
465 | * | |
466 | * Solve this conundrum by asking slave CPUs to do the backtrace | |
467 | * themselves. | |
468 | */ | |
469 | kgdb_info[cpu].exception_state |= DCPU_WANT_BT; | |
470 | while (kgdb_info[cpu].exception_state & DCPU_WANT_BT) | |
471 | cpu_relax(); | |
472 | } | |
473 | #endif | |
474 | ||
dc7d5527 JW |
475 | /* |
476 | * Return true if there is a valid kgdb I/O module. Also if no | |
477 | * debugger is attached a message can be printed to the console about | |
478 | * waiting for the debugger to attach. | |
479 | * | |
480 | * The print_wait argument is only to be true when called from inside | |
481 | * the core kgdb_handle_exception, because it will wait for the | |
482 | * debugger to attach. | |
483 | */ | |
484 | static int kgdb_io_ready(int print_wait) | |
485 | { | |
53197fc4 | 486 | if (!dbg_io_ops) |
dc7d5527 JW |
487 | return 0; |
488 | if (kgdb_connected) | |
489 | return 1; | |
490 | if (atomic_read(&kgdb_setting_breakpoint)) | |
491 | return 1; | |
dcc78711 JW |
492 | if (print_wait) { |
493 | #ifdef CONFIG_KGDB_KDB | |
494 | if (!dbg_kdb_mode) | |
0f16996c | 495 | pr_crit("waiting... or $3#33 for KDB\n"); |
dcc78711 | 496 | #else |
0f16996c | 497 | pr_crit("Waiting for remote debugger\n"); |
dcc78711 JW |
498 | #endif |
499 | } | |
dc7d5527 JW |
500 | return 1; |
501 | } | |
502 | ||
dc7d5527 JW |
503 | static int kgdb_reenter_check(struct kgdb_state *ks) |
504 | { | |
505 | unsigned long addr; | |
506 | ||
507 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) | |
508 | return 0; | |
509 | ||
510 | /* Panic on recursive debugger calls: */ | |
511 | exception_level++; | |
512 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); | |
dcc78711 | 513 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 JW |
514 | |
515 | /* | |
516 | * If the break point removed ok at the place exception | |
517 | * occurred, try to recover and print a warning to the end | |
518 | * user because the user planted a breakpoint in a place that | |
519 | * KGDB needs in order to function. | |
520 | */ | |
53197fc4 | 521 | if (dbg_remove_sw_break(addr) == 0) { |
dc7d5527 JW |
522 | exception_level = 0; |
523 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); | |
53197fc4 | 524 | dbg_activate_sw_breakpoints(); |
0f16996c | 525 | pr_crit("re-enter error: breakpoint removed %lx\n", addr); |
dc7d5527 JW |
526 | WARN_ON_ONCE(1); |
527 | ||
528 | return 1; | |
529 | } | |
53197fc4 | 530 | dbg_remove_all_break(); |
dc7d5527 JW |
531 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
532 | ||
533 | if (exception_level > 1) { | |
534 | dump_stack(); | |
535 | panic("Recursive entry to debugger"); | |
536 | } | |
537 | ||
0f16996c | 538 | pr_crit("re-enter exception: ALL breakpoints killed\n"); |
6d906340 JW |
539 | #ifdef CONFIG_KGDB_KDB |
540 | /* Allow kdb to debug itself one level */ | |
541 | return 0; | |
542 | #endif | |
dc7d5527 JW |
543 | dump_stack(); |
544 | panic("Recursive entry to debugger"); | |
545 | ||
546 | return 1; | |
547 | } | |
548 | ||
16cdc628 JW |
549 | static void dbg_touch_watchdogs(void) |
550 | { | |
551 | touch_softlockup_watchdog_sync(); | |
552 | clocksource_touch_watchdog(); | |
fb70b588 | 553 | rcu_cpu_stall_reset(); |
16cdc628 JW |
554 | } |
555 | ||
dfee3a7b JW |
556 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, |
557 | int exception_state) | |
dc7d5527 | 558 | { |
dc7d5527 | 559 | unsigned long flags; |
028e7b17 | 560 | int sstep_tries = 100; |
dcc78711 | 561 | int error; |
dfee3a7b | 562 | int cpu; |
4da75b9c | 563 | int trace_on = 0; |
dfee3a7b | 564 | int online_cpus = num_online_cpus(); |
a1465d2f | 565 | u64 time_left; |
c1bb9a9c | 566 | |
dfee3a7b JW |
567 | kgdb_info[ks->cpu].enter_kgdb++; |
568 | kgdb_info[ks->cpu].exception_state |= exception_state; | |
569 | ||
570 | if (exception_state == DCPU_WANT_MASTER) | |
571 | atomic_inc(&masters_in_kgdb); | |
572 | else | |
573 | atomic_inc(&slaves_in_kgdb); | |
d7ba979d DD |
574 | |
575 | if (arch_kgdb_ops.disable_hw_break) | |
576 | arch_kgdb_ops.disable_hw_break(regs); | |
c1bb9a9c | 577 | |
dc7d5527 JW |
578 | acquirelock: |
579 | /* | |
580 | * Interrupts will be restored by the 'trap return' code, except when | |
581 | * single stepping. | |
582 | */ | |
583 | local_irq_save(flags); | |
584 | ||
62fae312 JW |
585 | cpu = ks->cpu; |
586 | kgdb_info[cpu].debuggerinfo = regs; | |
587 | kgdb_info[cpu].task = current; | |
dcc78711 JW |
588 | kgdb_info[cpu].ret_state = 0; |
589 | kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; | |
dc7d5527 | 590 | |
dfee3a7b JW |
591 | /* Make sure the above info reaches the primary CPU */ |
592 | smp_mb(); | |
593 | ||
594 | if (exception_level == 1) { | |
595 | if (raw_spin_trylock(&dbg_master_lock)) | |
596 | atomic_xchg(&kgdb_active, cpu); | |
6d906340 | 597 | goto cpu_master_loop; |
dfee3a7b | 598 | } |
6d906340 | 599 | |
dc7d5527 | 600 | /* |
62fae312 JW |
601 | * CPU will loop if it is a slave or request to become a kgdb |
602 | * master cpu and acquire the kgdb_active lock: | |
dc7d5527 | 603 | */ |
62fae312 | 604 | while (1) { |
dcc78711 JW |
605 | cpu_loop: |
606 | if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) { | |
607 | kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER; | |
608 | goto cpu_master_loop; | |
609 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { | |
dfee3a7b JW |
610 | if (raw_spin_trylock(&dbg_master_lock)) { |
611 | atomic_xchg(&kgdb_active, cpu); | |
62fae312 | 612 | break; |
dfee3a7b | 613 | } |
2277b492 DA |
614 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_BT) { |
615 | dump_stack(); | |
616 | kgdb_info[cpu].exception_state &= ~DCPU_WANT_BT; | |
62fae312 | 617 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
dfee3a7b | 618 | if (!raw_spin_is_locked(&dbg_slave_lock)) |
62fae312 JW |
619 | goto return_normal; |
620 | } else { | |
621 | return_normal: | |
622 | /* Return to normal operation by executing any | |
623 | * hw breakpoint fixup. | |
624 | */ | |
625 | if (arch_kgdb_ops.correct_hw_break) | |
626 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
627 | if (trace_on) |
628 | tracing_on(); | |
162bc7f5 DA |
629 | kgdb_info[cpu].debuggerinfo = NULL; |
630 | kgdb_info[cpu].task = NULL; | |
dfee3a7b JW |
631 | kgdb_info[cpu].exception_state &= |
632 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
633 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 634 | smp_mb__before_atomic(); |
dfee3a7b | 635 | atomic_dec(&slaves_in_kgdb); |
16cdc628 | 636 | dbg_touch_watchdogs(); |
62fae312 JW |
637 | local_irq_restore(flags); |
638 | return 0; | |
639 | } | |
dc7d5527 | 640 | cpu_relax(); |
62fae312 | 641 | } |
dc7d5527 JW |
642 | |
643 | /* | |
028e7b17 | 644 | * For single stepping, try to only enter on the processor |
25985edc | 645 | * that was single stepping. To guard against a deadlock, the |
028e7b17 JW |
646 | * kernel will only try for the value of sstep_tries before |
647 | * giving up and continuing on. | |
dc7d5527 JW |
648 | */ |
649 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && | |
028e7b17 JW |
650 | (kgdb_info[cpu].task && |
651 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { | |
dc7d5527 | 652 | atomic_set(&kgdb_active, -1); |
dfee3a7b | 653 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 654 | dbg_touch_watchdogs(); |
dc7d5527 JW |
655 | local_irq_restore(flags); |
656 | ||
657 | goto acquirelock; | |
658 | } | |
659 | ||
660 | if (!kgdb_io_ready(1)) { | |
dcc78711 | 661 | kgdb_info[cpu].ret_state = 1; |
53197fc4 | 662 | goto kgdb_restore; /* No I/O connection, resume the system */ |
dc7d5527 JW |
663 | } |
664 | ||
665 | /* | |
666 | * Don't enter if we have hit a removed breakpoint. | |
667 | */ | |
668 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) | |
669 | goto kgdb_restore; | |
670 | ||
671 | /* Call the I/O driver's pre_exception routine */ | |
53197fc4 JW |
672 | if (dbg_io_ops->pre_exception) |
673 | dbg_io_ops->pre_exception(); | |
dc7d5527 | 674 | |
dc7d5527 JW |
675 | /* |
676 | * Get the passive CPU lock which will hold all the non-primary | |
677 | * CPU in a spin state while the debugger is active | |
678 | */ | |
dfee3a7b JW |
679 | if (!kgdb_single_step) |
680 | raw_spin_lock(&dbg_slave_lock); | |
dc7d5527 | 681 | |
56fb7093 | 682 | #ifdef CONFIG_SMP |
8daaa5f8 MT |
683 | /* If send_ready set, slaves are already waiting */ |
684 | if (ks->send_ready) | |
685 | atomic_set(ks->send_ready, 1); | |
686 | ||
56fb7093 | 687 | /* Signal the other CPUs to enter kgdb_wait() */ |
8daaa5f8 | 688 | else if ((!kgdb_single_step) && kgdb_do_roundup) |
9ef7fa50 | 689 | kgdb_roundup_cpus(); |
56fb7093 JW |
690 | #endif |
691 | ||
dc7d5527 JW |
692 | /* |
693 | * Wait for the other CPUs to be notified and be waiting for us: | |
694 | */ | |
2d13bb64 | 695 | time_left = MSEC_PER_SEC; |
a1465d2f DT |
696 | while (kgdb_do_roundup && --time_left && |
697 | (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) != | |
698 | online_cpus) | |
2d13bb64 | 699 | udelay(1000); |
a1465d2f | 700 | if (!time_left) |
df0036d1 | 701 | pr_crit("Timed out waiting for secondary CPUs.\n"); |
dc7d5527 JW |
702 | |
703 | /* | |
704 | * At this point the primary processor is completely | |
705 | * in the debugger and all secondary CPUs are quiescent | |
706 | */ | |
dcc78711 | 707 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 | 708 | kgdb_single_step = 0; |
d7161a65 | 709 | kgdb_contthread = current; |
dc7d5527 | 710 | exception_level = 0; |
4da75b9c JW |
711 | trace_on = tracing_is_on(); |
712 | if (trace_on) | |
713 | tracing_off(); | |
dc7d5527 | 714 | |
dcc78711 JW |
715 | while (1) { |
716 | cpu_master_loop: | |
717 | if (dbg_kdb_mode) { | |
718 | kgdb_connected = 1; | |
719 | error = kdb_stub(ks); | |
3fa43aba JW |
720 | if (error == -1) |
721 | continue; | |
b0679c63 | 722 | kgdb_connected = 0; |
dcc78711 JW |
723 | } else { |
724 | error = gdb_serial_stub(ks); | |
725 | } | |
726 | ||
727 | if (error == DBG_PASS_EVENT) { | |
728 | dbg_kdb_mode = !dbg_kdb_mode; | |
dcc78711 | 729 | } else if (error == DBG_SWITCH_CPU_EVENT) { |
495363d3 JW |
730 | kgdb_info[dbg_switch_cpu].exception_state |= |
731 | DCPU_NEXT_MASTER; | |
dcc78711 JW |
732 | goto cpu_loop; |
733 | } else { | |
734 | kgdb_info[cpu].ret_state = error; | |
735 | break; | |
736 | } | |
737 | } | |
dc7d5527 JW |
738 | |
739 | /* Call the I/O driver's post_exception routine */ | |
53197fc4 JW |
740 | if (dbg_io_ops->post_exception) |
741 | dbg_io_ops->post_exception(); | |
dc7d5527 | 742 | |
d7161a65 | 743 | if (!kgdb_single_step) { |
dfee3a7b JW |
744 | raw_spin_unlock(&dbg_slave_lock); |
745 | /* Wait till all the CPUs have quit from the debugger. */ | |
746 | while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb)) | |
747 | cpu_relax(); | |
dc7d5527 JW |
748 | } |
749 | ||
750 | kgdb_restore: | |
028e7b17 JW |
751 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
752 | int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); | |
753 | if (kgdb_info[sstep_cpu].task) | |
754 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; | |
755 | else | |
756 | kgdb_sstep_pid = 0; | |
757 | } | |
c1bb9a9c DD |
758 | if (arch_kgdb_ops.correct_hw_break) |
759 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
760 | if (trace_on) |
761 | tracing_on(); | |
dfee3a7b | 762 | |
162bc7f5 DA |
763 | kgdb_info[cpu].debuggerinfo = NULL; |
764 | kgdb_info[cpu].task = NULL; | |
dfee3a7b JW |
765 | kgdb_info[cpu].exception_state &= |
766 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
767 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 768 | smp_mb__before_atomic(); |
dfee3a7b | 769 | atomic_dec(&masters_in_kgdb); |
dc7d5527 JW |
770 | /* Free kgdb_active */ |
771 | atomic_set(&kgdb_active, -1); | |
dfee3a7b | 772 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 773 | dbg_touch_watchdogs(); |
dc7d5527 JW |
774 | local_irq_restore(flags); |
775 | ||
dcc78711 | 776 | return kgdb_info[cpu].ret_state; |
dc7d5527 JW |
777 | } |
778 | ||
62fae312 JW |
779 | /* |
780 | * kgdb_handle_exception() - main entry point from a kernel exception | |
781 | * | |
782 | * Locking hierarchy: | |
783 | * interface locks, if any (begin_session) | |
784 | * kgdb lock (kgdb_active) | |
785 | */ | |
786 | int | |
787 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) | |
788 | { | |
789 | struct kgdb_state kgdb_var; | |
790 | struct kgdb_state *ks = &kgdb_var; | |
5a14fead AV |
791 | int ret = 0; |
792 | ||
793 | if (arch_kgdb_ops.enable_nmi) | |
794 | arch_kgdb_ops.enable_nmi(0); | |
5516fd7b CC |
795 | /* |
796 | * Avoid entering the debugger if we were triggered due to an oops | |
797 | * but panic_timeout indicates the system should automatically | |
798 | * reboot on panic. We don't want to get stuck waiting for input | |
799 | * on such systems, especially if its "just" an oops. | |
800 | */ | |
801 | if (signo != SIGTRAP && panic_timeout) | |
802 | return 1; | |
62fae312 | 803 | |
8daaa5f8 | 804 | memset(ks, 0, sizeof(struct kgdb_state)); |
62fae312 JW |
805 | ks->cpu = raw_smp_processor_id(); |
806 | ks->ex_vector = evector; | |
807 | ks->signo = signo; | |
62fae312 | 808 | ks->err_code = ecode; |
62fae312 JW |
809 | ks->linux_regs = regs; |
810 | ||
811 | if (kgdb_reenter_check(ks)) | |
5a14fead | 812 | goto out; /* Ouch, double exception ! */ |
dfee3a7b | 813 | if (kgdb_info[ks->cpu].enter_kgdb != 0) |
5a14fead | 814 | goto out; |
dfee3a7b | 815 | |
5a14fead AV |
816 | ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
817 | out: | |
818 | if (arch_kgdb_ops.enable_nmi) | |
819 | arch_kgdb_ops.enable_nmi(1); | |
820 | return ret; | |
62fae312 JW |
821 | } |
822 | ||
f30fed10 | 823 | /* |
d8a050f5 | 824 | * GDB places a breakpoint at this function to know dynamically loaded objects. |
f30fed10 | 825 | */ |
f30fed10 JW |
826 | static int module_event(struct notifier_block *self, unsigned long val, |
827 | void *data) | |
828 | { | |
829 | return 0; | |
830 | } | |
831 | ||
832 | static struct notifier_block dbg_module_load_nb = { | |
833 | .notifier_call = module_event, | |
834 | }; | |
835 | ||
dc7d5527 JW |
836 | int kgdb_nmicallback(int cpu, void *regs) |
837 | { | |
838 | #ifdef CONFIG_SMP | |
62fae312 JW |
839 | struct kgdb_state kgdb_var; |
840 | struct kgdb_state *ks = &kgdb_var; | |
841 | ||
87b09592 DA |
842 | kgdb_info[cpu].rounding_up = false; |
843 | ||
62fae312 JW |
844 | memset(ks, 0, sizeof(struct kgdb_state)); |
845 | ks->cpu = cpu; | |
846 | ks->linux_regs = regs; | |
847 | ||
dfee3a7b JW |
848 | if (kgdb_info[ks->cpu].enter_kgdb == 0 && |
849 | raw_spin_is_locked(&dbg_master_lock)) { | |
850 | kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); | |
dc7d5527 JW |
851 | return 0; |
852 | } | |
853 | #endif | |
854 | return 1; | |
855 | } | |
856 | ||
fc8b1374 MT |
857 | int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, |
858 | atomic_t *send_ready) | |
8daaa5f8 MT |
859 | { |
860 | #ifdef CONFIG_SMP | |
861 | if (!kgdb_io_ready(0) || !send_ready) | |
862 | return 1; | |
863 | ||
864 | if (kgdb_info[cpu].enter_kgdb == 0) { | |
865 | struct kgdb_state kgdb_var; | |
866 | struct kgdb_state *ks = &kgdb_var; | |
867 | ||
868 | memset(ks, 0, sizeof(struct kgdb_state)); | |
869 | ks->cpu = cpu; | |
870 | ks->ex_vector = trapnr; | |
871 | ks->signo = SIGTRAP; | |
fc8b1374 | 872 | ks->err_code = err_code; |
8daaa5f8 MT |
873 | ks->linux_regs = regs; |
874 | ks->send_ready = send_ready; | |
875 | kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); | |
876 | return 0; | |
877 | } | |
878 | #endif | |
879 | return 1; | |
880 | } | |
881 | ||
aabdc3b8 JW |
882 | static void kgdb_console_write(struct console *co, const char *s, |
883 | unsigned count) | |
dc7d5527 JW |
884 | { |
885 | unsigned long flags; | |
886 | ||
887 | /* If we're debugging, or KGDB has not connected, don't try | |
888 | * and print. */ | |
dcc78711 | 889 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) |
dc7d5527 JW |
890 | return; |
891 | ||
892 | local_irq_save(flags); | |
53197fc4 | 893 | gdbstub_msg_write(s, count); |
dc7d5527 JW |
894 | local_irq_restore(flags); |
895 | } | |
896 | ||
897 | static struct console kgdbcons = { | |
898 | .name = "kgdb", | |
899 | .write = kgdb_console_write, | |
900 | .flags = CON_PRINTBUFFER | CON_ENABLED, | |
901 | .index = -1, | |
902 | }; | |
903 | ||
904 | #ifdef CONFIG_MAGIC_SYSRQ | |
1495cc9d | 905 | static void sysrq_handle_dbg(int key) |
dc7d5527 | 906 | { |
53197fc4 | 907 | if (!dbg_io_ops) { |
0f16996c | 908 | pr_crit("ERROR: No KGDB I/O module available\n"); |
dc7d5527 JW |
909 | return; |
910 | } | |
dcc78711 JW |
911 | if (!kgdb_connected) { |
912 | #ifdef CONFIG_KGDB_KDB | |
913 | if (!dbg_kdb_mode) | |
0f16996c | 914 | pr_crit("KGDB or $3#33 for KDB\n"); |
dcc78711 | 915 | #else |
0f16996c | 916 | pr_crit("Entering KGDB\n"); |
dcc78711 JW |
917 | #endif |
918 | } | |
dc7d5527 JW |
919 | |
920 | kgdb_breakpoint(); | |
921 | } | |
922 | ||
53197fc4 JW |
923 | static struct sysrq_key_op sysrq_dbg_op = { |
924 | .handler = sysrq_handle_dbg, | |
f3456509 | 925 | .help_msg = "debug(g)", |
364b5b7b | 926 | .action_msg = "DEBUG", |
dc7d5527 JW |
927 | }; |
928 | #endif | |
929 | ||
7d92bda2 | 930 | void kgdb_panic(const char *msg) |
4402c153 | 931 | { |
7d92bda2 DA |
932 | if (!kgdb_io_module_registered) |
933 | return; | |
934 | ||
5516fd7b | 935 | /* |
7d92bda2 DA |
936 | * We don't want to get stuck waiting for input from user if |
937 | * "panic_timeout" indicates the system should automatically | |
5516fd7b CC |
938 | * reboot on panic. |
939 | */ | |
940 | if (panic_timeout) | |
7d92bda2 | 941 | return; |
5516fd7b | 942 | |
4402c153 | 943 | if (dbg_kdb_mode) |
7d92bda2 DA |
944 | kdb_printf("PANIC: %s\n", msg); |
945 | ||
4402c153 | 946 | kgdb_breakpoint(); |
4402c153 JW |
947 | } |
948 | ||
0b4b3827 JW |
949 | void __weak kgdb_arch_late(void) |
950 | { | |
951 | } | |
952 | ||
953 | void __init dbg_late_init(void) | |
954 | { | |
955 | dbg_is_early = false; | |
956 | if (kgdb_io_module_registered) | |
957 | kgdb_arch_late(); | |
958 | kdb_init(KDB_INIT_FULL); | |
959 | } | |
960 | ||
2366e047 JW |
961 | static int |
962 | dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x) | |
963 | { | |
bec4d62e JW |
964 | /* |
965 | * Take the following action on reboot notify depending on value: | |
966 | * 1 == Enter debugger | |
967 | * 0 == [the default] detatch debug client | |
968 | * -1 == Do nothing... and use this until the board resets | |
969 | */ | |
970 | switch (kgdbreboot) { | |
971 | case 1: | |
972 | kgdb_breakpoint(); | |
973 | case -1: | |
974 | goto done; | |
975 | } | |
2366e047 JW |
976 | if (!dbg_kdb_mode) |
977 | gdbstub_exit(code); | |
bec4d62e | 978 | done: |
2366e047 JW |
979 | return NOTIFY_DONE; |
980 | } | |
981 | ||
982 | static struct notifier_block dbg_reboot_notifier = { | |
983 | .notifier_call = dbg_notify_reboot, | |
984 | .next = NULL, | |
985 | .priority = INT_MAX, | |
986 | }; | |
987 | ||
dc7d5527 JW |
988 | static void kgdb_register_callbacks(void) |
989 | { | |
990 | if (!kgdb_io_module_registered) { | |
991 | kgdb_io_module_registered = 1; | |
992 | kgdb_arch_init(); | |
0b4b3827 JW |
993 | if (!dbg_is_early) |
994 | kgdb_arch_late(); | |
f30fed10 | 995 | register_module_notifier(&dbg_module_load_nb); |
2366e047 | 996 | register_reboot_notifier(&dbg_reboot_notifier); |
dc7d5527 | 997 | #ifdef CONFIG_MAGIC_SYSRQ |
53197fc4 | 998 | register_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
999 | #endif |
1000 | if (kgdb_use_con && !kgdb_con_registered) { | |
1001 | register_console(&kgdbcons); | |
1002 | kgdb_con_registered = 1; | |
1003 | } | |
1004 | } | |
1005 | } | |
1006 | ||
1007 | static void kgdb_unregister_callbacks(void) | |
1008 | { | |
1009 | /* | |
7d92bda2 DA |
1010 | * When this routine is called KGDB should unregister from |
1011 | * handlers and clean up, making sure it is not handling any | |
dc7d5527 JW |
1012 | * break exceptions at the time. |
1013 | */ | |
1014 | if (kgdb_io_module_registered) { | |
1015 | kgdb_io_module_registered = 0; | |
2366e047 | 1016 | unregister_reboot_notifier(&dbg_reboot_notifier); |
f30fed10 | 1017 | unregister_module_notifier(&dbg_module_load_nb); |
dc7d5527 JW |
1018 | kgdb_arch_exit(); |
1019 | #ifdef CONFIG_MAGIC_SYSRQ | |
53197fc4 | 1020 | unregister_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
1021 | #endif |
1022 | if (kgdb_con_registered) { | |
1023 | unregister_console(&kgdbcons); | |
1024 | kgdb_con_registered = 0; | |
1025 | } | |
1026 | } | |
1027 | } | |
1028 | ||
1cee5e35 JW |
1029 | /* |
1030 | * There are times a tasklet needs to be used vs a compiled in | |
1031 | * break point so as to cause an exception outside a kgdb I/O module, | |
1032 | * such as is the case with kgdboe, where calling a breakpoint in the | |
1033 | * I/O driver itself would be fatal. | |
1034 | */ | |
1035 | static void kgdb_tasklet_bpt(unsigned long ing) | |
1036 | { | |
1037 | kgdb_breakpoint(); | |
1038 | atomic_set(&kgdb_break_tasklet_var, 0); | |
1039 | } | |
1040 | ||
1041 | static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0); | |
1042 | ||
1043 | void kgdb_schedule_breakpoint(void) | |
1044 | { | |
1045 | if (atomic_read(&kgdb_break_tasklet_var) || | |
1046 | atomic_read(&kgdb_active) != -1 || | |
1047 | atomic_read(&kgdb_setting_breakpoint)) | |
1048 | return; | |
1049 | atomic_inc(&kgdb_break_tasklet_var); | |
1050 | tasklet_schedule(&kgdb_tasklet_breakpoint); | |
1051 | } | |
1052 | EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint); | |
1053 | ||
dc7d5527 JW |
1054 | static void kgdb_initial_breakpoint(void) |
1055 | { | |
1056 | kgdb_break_asap = 0; | |
1057 | ||
0f16996c | 1058 | pr_crit("Waiting for connection from remote gdb...\n"); |
dc7d5527 JW |
1059 | kgdb_breakpoint(); |
1060 | } | |
1061 | ||
1062 | /** | |
737a460f | 1063 | * kgdb_register_io_module - register KGDB IO module |
53197fc4 | 1064 | * @new_dbg_io_ops: the io ops vector |
dc7d5527 JW |
1065 | * |
1066 | * Register it with the KGDB core. | |
1067 | */ | |
53197fc4 | 1068 | int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
dc7d5527 JW |
1069 | { |
1070 | int err; | |
1071 | ||
1072 | spin_lock(&kgdb_registration_lock); | |
1073 | ||
53197fc4 | 1074 | if (dbg_io_ops) { |
dc7d5527 JW |
1075 | spin_unlock(&kgdb_registration_lock); |
1076 | ||
0f16996c | 1077 | pr_err("Another I/O driver is already registered with KGDB\n"); |
dc7d5527 JW |
1078 | return -EBUSY; |
1079 | } | |
1080 | ||
53197fc4 JW |
1081 | if (new_dbg_io_ops->init) { |
1082 | err = new_dbg_io_ops->init(); | |
dc7d5527 JW |
1083 | if (err) { |
1084 | spin_unlock(&kgdb_registration_lock); | |
1085 | return err; | |
1086 | } | |
1087 | } | |
1088 | ||
53197fc4 | 1089 | dbg_io_ops = new_dbg_io_ops; |
dc7d5527 JW |
1090 | |
1091 | spin_unlock(&kgdb_registration_lock); | |
1092 | ||
0f16996c | 1093 | pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name); |
dc7d5527 JW |
1094 | |
1095 | /* Arm KGDB now. */ | |
1096 | kgdb_register_callbacks(); | |
1097 | ||
1098 | if (kgdb_break_asap) | |
1099 | kgdb_initial_breakpoint(); | |
1100 | ||
1101 | return 0; | |
1102 | } | |
1103 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); | |
1104 | ||
1105 | /** | |
1106 | * kkgdb_unregister_io_module - unregister KGDB IO module | |
53197fc4 | 1107 | * @old_dbg_io_ops: the io ops vector |
dc7d5527 JW |
1108 | * |
1109 | * Unregister it with the KGDB core. | |
1110 | */ | |
53197fc4 | 1111 | void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
dc7d5527 JW |
1112 | { |
1113 | BUG_ON(kgdb_connected); | |
1114 | ||
1115 | /* | |
1116 | * KGDB is no longer able to communicate out, so | |
1117 | * unregister our callbacks and reset state. | |
1118 | */ | |
1119 | kgdb_unregister_callbacks(); | |
1120 | ||
1121 | spin_lock(&kgdb_registration_lock); | |
1122 | ||
53197fc4 JW |
1123 | WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); |
1124 | dbg_io_ops = NULL; | |
dc7d5527 JW |
1125 | |
1126 | spin_unlock(&kgdb_registration_lock); | |
1127 | ||
0f16996c | 1128 | pr_info("Unregistered I/O driver %s, debugger disabled\n", |
53197fc4 | 1129 | old_dbg_io_ops->name); |
dc7d5527 JW |
1130 | } |
1131 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); | |
1132 | ||
dcc78711 JW |
1133 | int dbg_io_get_char(void) |
1134 | { | |
1135 | int ret = dbg_io_ops->read_char(); | |
f5316b4a JW |
1136 | if (ret == NO_POLL_CHAR) |
1137 | return -1; | |
dcc78711 JW |
1138 | if (!dbg_kdb_mode) |
1139 | return ret; | |
1140 | if (ret == 127) | |
1141 | return 8; | |
1142 | return ret; | |
1143 | } | |
1144 | ||
dc7d5527 JW |
1145 | /** |
1146 | * kgdb_breakpoint - generate breakpoint exception | |
1147 | * | |
1148 | * This function will generate a breakpoint exception. It is used at the | |
1149 | * beginning of a program to sync up with a debugger and can be used | |
1150 | * otherwise as a quick means to stop program execution and "break" into | |
1151 | * the debugger. | |
1152 | */ | |
d498d4b4 | 1153 | noinline void kgdb_breakpoint(void) |
dc7d5527 | 1154 | { |
ae6bf53e | 1155 | atomic_inc(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1156 | wmb(); /* Sync point before breakpoint */ |
1157 | arch_kgdb_breakpoint(); | |
1158 | wmb(); /* Sync point after breakpoint */ | |
ae6bf53e | 1159 | atomic_dec(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1160 | } |
1161 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); | |
1162 | ||
1163 | static int __init opt_kgdb_wait(char *str) | |
1164 | { | |
1165 | kgdb_break_asap = 1; | |
1166 | ||
dcc78711 | 1167 | kdb_init(KDB_INIT_EARLY); |
dc7d5527 JW |
1168 | if (kgdb_io_module_registered) |
1169 | kgdb_initial_breakpoint(); | |
1170 | ||
1171 | return 0; | |
1172 | } | |
1173 | ||
1174 | early_param("kgdbwait", opt_kgdb_wait); |