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Commit | Line | Data |
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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> |
dc7d5527 JW |
58 | |
59 | #include <asm/cacheflush.h> | |
60 | #include <asm/byteorder.h> | |
60063497 | 61 | #include <linux/atomic.h> |
dc7d5527 | 62 | |
53197fc4 | 63 | #include "debug_core.h" |
dc7d5527 | 64 | |
53197fc4 | 65 | static int kgdb_break_asap; |
62fae312 | 66 | |
53197fc4 | 67 | struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
dc7d5527 JW |
68 | |
69 | /** | |
70 | * kgdb_connected - Is a host GDB connected to us? | |
71 | */ | |
72 | int kgdb_connected; | |
73 | EXPORT_SYMBOL_GPL(kgdb_connected); | |
74 | ||
75 | /* All the KGDB handlers are installed */ | |
f503b5ae | 76 | int kgdb_io_module_registered; |
dc7d5527 JW |
77 | |
78 | /* Guard for recursive entry */ | |
79 | static int exception_level; | |
80 | ||
53197fc4 | 81 | struct kgdb_io *dbg_io_ops; |
dc7d5527 JW |
82 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
83 | ||
bec4d62e JW |
84 | /* Action for the reboot notifiter, a global allow kdb to change it */ |
85 | static int kgdbreboot; | |
dc7d5527 JW |
86 | /* kgdb console driver is loaded */ |
87 | static int kgdb_con_registered; | |
88 | /* determine if kgdb console output should be used */ | |
89 | static int kgdb_use_con; | |
0b4b3827 JW |
90 | /* Flag for alternate operations for early debugging */ |
91 | bool dbg_is_early = true; | |
dcc78711 JW |
92 | /* Next cpu to become the master debug core */ |
93 | int dbg_switch_cpu; | |
94 | ||
95 | /* Use kdb or gdbserver mode */ | |
a0de055c | 96 | int dbg_kdb_mode = 1; |
dc7d5527 JW |
97 | |
98 | static int __init opt_kgdb_con(char *str) | |
99 | { | |
100 | kgdb_use_con = 1; | |
101 | return 0; | |
102 | } | |
103 | ||
104 | early_param("kgdbcon", opt_kgdb_con); | |
105 | ||
106 | module_param(kgdb_use_con, int, 0644); | |
bec4d62e | 107 | module_param(kgdbreboot, int, 0644); |
dc7d5527 JW |
108 | |
109 | /* | |
110 | * Holds information about breakpoints in a kernel. These breakpoints are | |
111 | * added and removed by gdb. | |
112 | */ | |
113 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { | |
114 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } | |
115 | }; | |
116 | ||
117 | /* | |
118 | * The CPU# of the active CPU, or -1 if none: | |
119 | */ | |
120 | atomic_t kgdb_active = ATOMIC_INIT(-1); | |
dcc78711 | 121 | EXPORT_SYMBOL_GPL(kgdb_active); |
dfee3a7b JW |
122 | static DEFINE_RAW_SPINLOCK(dbg_master_lock); |
123 | static DEFINE_RAW_SPINLOCK(dbg_slave_lock); | |
dc7d5527 JW |
124 | |
125 | /* | |
126 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early | |
127 | * bootup code (which might not have percpu set up yet): | |
128 | */ | |
dfee3a7b JW |
129 | static atomic_t masters_in_kgdb; |
130 | static atomic_t slaves_in_kgdb; | |
1cee5e35 | 131 | static atomic_t kgdb_break_tasklet_var; |
dc7d5527 JW |
132 | atomic_t kgdb_setting_breakpoint; |
133 | ||
134 | struct task_struct *kgdb_usethread; | |
135 | struct task_struct *kgdb_contthread; | |
136 | ||
137 | int kgdb_single_step; | |
53197fc4 | 138 | static pid_t kgdb_sstep_pid; |
dc7d5527 JW |
139 | |
140 | /* to keep track of the CPU which is doing the single stepping*/ | |
141 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); | |
142 | ||
143 | /* | |
144 | * If you are debugging a problem where roundup (the collection of | |
145 | * all other CPUs) is a problem [this should be extremely rare], | |
146 | * then use the nokgdbroundup option to avoid roundup. In that case | |
147 | * the other CPUs might interfere with your debugging context, so | |
148 | * use this with care: | |
149 | */ | |
688b744d | 150 | static int kgdb_do_roundup = 1; |
dc7d5527 JW |
151 | |
152 | static int __init opt_nokgdbroundup(char *str) | |
153 | { | |
154 | kgdb_do_roundup = 0; | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
159 | early_param("nokgdbroundup", opt_nokgdbroundup); | |
160 | ||
161 | /* | |
162 | * Finally, some KGDB code :-) | |
163 | */ | |
164 | ||
165 | /* | |
166 | * Weak aliases for breakpoint management, | |
167 | * can be overriden by architectures when needed: | |
168 | */ | |
98b54aa1 | 169 | int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 JW |
170 | { |
171 | int err; | |
172 | ||
98b54aa1 JW |
173 | err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, |
174 | BREAK_INSTR_SIZE); | |
dc7d5527 JW |
175 | if (err) |
176 | return err; | |
98b54aa1 JW |
177 | err = probe_kernel_write((char *)bpt->bpt_addr, |
178 | arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); | |
179 | return err; | |
dc7d5527 JW |
180 | } |
181 | ||
98b54aa1 | 182 | int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 | 183 | { |
98b54aa1 JW |
184 | return probe_kernel_write((char *)bpt->bpt_addr, |
185 | (char *)bpt->saved_instr, BREAK_INSTR_SIZE); | |
dc7d5527 JW |
186 | } |
187 | ||
a9b60bf4 JW |
188 | int __weak kgdb_validate_break_address(unsigned long addr) |
189 | { | |
98b54aa1 | 190 | struct kgdb_bkpt tmp; |
a9b60bf4 | 191 | int err; |
98b54aa1 | 192 | /* Validate setting the breakpoint and then removing it. If the |
a9b60bf4 JW |
193 | * remove fails, the kernel needs to emit a bad message because we |
194 | * are deep trouble not being able to put things back the way we | |
195 | * found them. | |
196 | */ | |
98b54aa1 JW |
197 | tmp.bpt_addr = addr; |
198 | err = kgdb_arch_set_breakpoint(&tmp); | |
a9b60bf4 JW |
199 | if (err) |
200 | return err; | |
98b54aa1 | 201 | err = kgdb_arch_remove_breakpoint(&tmp); |
a9b60bf4 | 202 | if (err) |
0f16996c FF |
203 | pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n", |
204 | addr); | |
a9b60bf4 JW |
205 | return err; |
206 | } | |
207 | ||
dc7d5527 JW |
208 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
209 | { | |
210 | return instruction_pointer(regs); | |
211 | } | |
212 | ||
213 | int __weak kgdb_arch_init(void) | |
214 | { | |
215 | return 0; | |
216 | } | |
217 | ||
b4b8ac52 JW |
218 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
219 | { | |
220 | return 0; | |
221 | } | |
222 | ||
dc7d5527 JW |
223 | /* |
224 | * Some architectures need cache flushes when we set/clear a | |
225 | * breakpoint: | |
226 | */ | |
227 | static void kgdb_flush_swbreak_addr(unsigned long addr) | |
228 | { | |
229 | if (!CACHE_FLUSH_IS_SAFE) | |
230 | return; | |
231 | ||
615d6e87 DB |
232 | if (current->mm) { |
233 | int i; | |
234 | ||
235 | for (i = 0; i < VMACACHE_SIZE; i++) { | |
314ff785 | 236 | if (!current->vmacache.vmas[i]) |
615d6e87 | 237 | continue; |
314ff785 | 238 | flush_cache_range(current->vmacache.vmas[i], |
615d6e87 DB |
239 | addr, addr + BREAK_INSTR_SIZE); |
240 | } | |
dc7d5527 | 241 | } |
615d6e87 | 242 | |
1a9a3e76 JW |
243 | /* Force flush instruction cache if it was outside the mm */ |
244 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); | |
dc7d5527 JW |
245 | } |
246 | ||
247 | /* | |
248 | * SW breakpoint management: | |
249 | */ | |
53197fc4 | 250 | int dbg_activate_sw_breakpoints(void) |
dc7d5527 | 251 | { |
7f8b7ed6 JW |
252 | int error; |
253 | int ret = 0; | |
dc7d5527 JW |
254 | int i; |
255 | ||
256 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
257 | if (kgdb_break[i].state != BP_SET) | |
258 | continue; | |
259 | ||
98b54aa1 | 260 | error = kgdb_arch_set_breakpoint(&kgdb_break[i]); |
7f8b7ed6 JW |
261 | if (error) { |
262 | ret = error; | |
0f16996c FF |
263 | pr_info("BP install failed: %lx\n", |
264 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
265 | continue; |
266 | } | |
dc7d5527 | 267 | |
98b54aa1 | 268 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
269 | kgdb_break[i].state = BP_ACTIVE; |
270 | } | |
7f8b7ed6 | 271 | return ret; |
dc7d5527 JW |
272 | } |
273 | ||
53197fc4 | 274 | int dbg_set_sw_break(unsigned long addr) |
dc7d5527 JW |
275 | { |
276 | int err = kgdb_validate_break_address(addr); | |
277 | int breakno = -1; | |
278 | int i; | |
279 | ||
280 | if (err) | |
281 | return err; | |
282 | ||
283 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
284 | if ((kgdb_break[i].state == BP_SET) && | |
285 | (kgdb_break[i].bpt_addr == addr)) | |
286 | return -EEXIST; | |
287 | } | |
288 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
289 | if (kgdb_break[i].state == BP_REMOVED && | |
290 | kgdb_break[i].bpt_addr == addr) { | |
291 | breakno = i; | |
292 | break; | |
293 | } | |
294 | } | |
295 | ||
296 | if (breakno == -1) { | |
297 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
298 | if (kgdb_break[i].state == BP_UNDEFINED) { | |
299 | breakno = i; | |
300 | break; | |
301 | } | |
302 | } | |
303 | } | |
304 | ||
305 | if (breakno == -1) | |
306 | return -E2BIG; | |
307 | ||
308 | kgdb_break[breakno].state = BP_SET; | |
309 | kgdb_break[breakno].type = BP_BREAKPOINT; | |
310 | kgdb_break[breakno].bpt_addr = addr; | |
311 | ||
312 | return 0; | |
313 | } | |
314 | ||
dcc78711 | 315 | int dbg_deactivate_sw_breakpoints(void) |
dc7d5527 | 316 | { |
7f8b7ed6 JW |
317 | int error; |
318 | int ret = 0; | |
dc7d5527 JW |
319 | int i; |
320 | ||
321 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
322 | if (kgdb_break[i].state != BP_ACTIVE) | |
323 | continue; | |
98b54aa1 | 324 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
7f8b7ed6 | 325 | if (error) { |
0f16996c FF |
326 | pr_info("BP remove failed: %lx\n", |
327 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
328 | ret = error; |
329 | } | |
dc7d5527 | 330 | |
98b54aa1 | 331 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
332 | kgdb_break[i].state = BP_SET; |
333 | } | |
7f8b7ed6 | 334 | return ret; |
dc7d5527 JW |
335 | } |
336 | ||
53197fc4 | 337 | int dbg_remove_sw_break(unsigned long addr) |
dc7d5527 JW |
338 | { |
339 | int i; | |
340 | ||
341 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
342 | if ((kgdb_break[i].state == BP_SET) && | |
343 | (kgdb_break[i].bpt_addr == addr)) { | |
344 | kgdb_break[i].state = BP_REMOVED; | |
345 | return 0; | |
346 | } | |
347 | } | |
348 | return -ENOENT; | |
349 | } | |
350 | ||
351 | int kgdb_isremovedbreak(unsigned long addr) | |
352 | { | |
353 | int i; | |
354 | ||
355 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
356 | if ((kgdb_break[i].state == BP_REMOVED) && | |
357 | (kgdb_break[i].bpt_addr == addr)) | |
358 | return 1; | |
359 | } | |
360 | return 0; | |
361 | } | |
362 | ||
53197fc4 | 363 | int dbg_remove_all_break(void) |
dc7d5527 | 364 | { |
dc7d5527 JW |
365 | int error; |
366 | int i; | |
367 | ||
368 | /* Clear memory breakpoints. */ | |
369 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
737a460f JW |
370 | if (kgdb_break[i].state != BP_ACTIVE) |
371 | goto setundefined; | |
98b54aa1 | 372 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
dc7d5527 | 373 | if (error) |
0f16996c | 374 | pr_err("breakpoint remove failed: %lx\n", |
98b54aa1 | 375 | kgdb_break[i].bpt_addr); |
737a460f JW |
376 | setundefined: |
377 | kgdb_break[i].state = BP_UNDEFINED; | |
dc7d5527 JW |
378 | } |
379 | ||
380 | /* Clear hardware breakpoints. */ | |
381 | if (arch_kgdb_ops.remove_all_hw_break) | |
382 | arch_kgdb_ops.remove_all_hw_break(); | |
383 | ||
384 | return 0; | |
385 | } | |
386 | ||
dc7d5527 JW |
387 | /* |
388 | * Return true if there is a valid kgdb I/O module. Also if no | |
389 | * debugger is attached a message can be printed to the console about | |
390 | * waiting for the debugger to attach. | |
391 | * | |
392 | * The print_wait argument is only to be true when called from inside | |
393 | * the core kgdb_handle_exception, because it will wait for the | |
394 | * debugger to attach. | |
395 | */ | |
396 | static int kgdb_io_ready(int print_wait) | |
397 | { | |
53197fc4 | 398 | if (!dbg_io_ops) |
dc7d5527 JW |
399 | return 0; |
400 | if (kgdb_connected) | |
401 | return 1; | |
402 | if (atomic_read(&kgdb_setting_breakpoint)) | |
403 | return 1; | |
dcc78711 JW |
404 | if (print_wait) { |
405 | #ifdef CONFIG_KGDB_KDB | |
406 | if (!dbg_kdb_mode) | |
0f16996c | 407 | pr_crit("waiting... or $3#33 for KDB\n"); |
dcc78711 | 408 | #else |
0f16996c | 409 | pr_crit("Waiting for remote debugger\n"); |
dcc78711 JW |
410 | #endif |
411 | } | |
dc7d5527 JW |
412 | return 1; |
413 | } | |
414 | ||
dc7d5527 JW |
415 | static int kgdb_reenter_check(struct kgdb_state *ks) |
416 | { | |
417 | unsigned long addr; | |
418 | ||
419 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) | |
420 | return 0; | |
421 | ||
422 | /* Panic on recursive debugger calls: */ | |
423 | exception_level++; | |
424 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); | |
dcc78711 | 425 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 JW |
426 | |
427 | /* | |
428 | * If the break point removed ok at the place exception | |
429 | * occurred, try to recover and print a warning to the end | |
430 | * user because the user planted a breakpoint in a place that | |
431 | * KGDB needs in order to function. | |
432 | */ | |
53197fc4 | 433 | if (dbg_remove_sw_break(addr) == 0) { |
dc7d5527 JW |
434 | exception_level = 0; |
435 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); | |
53197fc4 | 436 | dbg_activate_sw_breakpoints(); |
0f16996c | 437 | pr_crit("re-enter error: breakpoint removed %lx\n", addr); |
dc7d5527 JW |
438 | WARN_ON_ONCE(1); |
439 | ||
440 | return 1; | |
441 | } | |
53197fc4 | 442 | dbg_remove_all_break(); |
dc7d5527 JW |
443 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
444 | ||
445 | if (exception_level > 1) { | |
446 | dump_stack(); | |
447 | panic("Recursive entry to debugger"); | |
448 | } | |
449 | ||
0f16996c | 450 | pr_crit("re-enter exception: ALL breakpoints killed\n"); |
6d906340 JW |
451 | #ifdef CONFIG_KGDB_KDB |
452 | /* Allow kdb to debug itself one level */ | |
453 | return 0; | |
454 | #endif | |
dc7d5527 JW |
455 | dump_stack(); |
456 | panic("Recursive entry to debugger"); | |
457 | ||
458 | return 1; | |
459 | } | |
460 | ||
16cdc628 JW |
461 | static void dbg_touch_watchdogs(void) |
462 | { | |
463 | touch_softlockup_watchdog_sync(); | |
464 | clocksource_touch_watchdog(); | |
fb70b588 | 465 | rcu_cpu_stall_reset(); |
16cdc628 JW |
466 | } |
467 | ||
dfee3a7b JW |
468 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, |
469 | int exception_state) | |
dc7d5527 | 470 | { |
dc7d5527 | 471 | unsigned long flags; |
028e7b17 | 472 | int sstep_tries = 100; |
dcc78711 | 473 | int error; |
dfee3a7b | 474 | int cpu; |
4da75b9c | 475 | int trace_on = 0; |
dfee3a7b | 476 | int online_cpus = num_online_cpus(); |
a1465d2f | 477 | u64 time_left; |
c1bb9a9c | 478 | |
dfee3a7b JW |
479 | kgdb_info[ks->cpu].enter_kgdb++; |
480 | kgdb_info[ks->cpu].exception_state |= exception_state; | |
481 | ||
482 | if (exception_state == DCPU_WANT_MASTER) | |
483 | atomic_inc(&masters_in_kgdb); | |
484 | else | |
485 | atomic_inc(&slaves_in_kgdb); | |
d7ba979d DD |
486 | |
487 | if (arch_kgdb_ops.disable_hw_break) | |
488 | arch_kgdb_ops.disable_hw_break(regs); | |
c1bb9a9c | 489 | |
dc7d5527 JW |
490 | acquirelock: |
491 | /* | |
492 | * Interrupts will be restored by the 'trap return' code, except when | |
493 | * single stepping. | |
494 | */ | |
495 | local_irq_save(flags); | |
496 | ||
62fae312 JW |
497 | cpu = ks->cpu; |
498 | kgdb_info[cpu].debuggerinfo = regs; | |
499 | kgdb_info[cpu].task = current; | |
dcc78711 JW |
500 | kgdb_info[cpu].ret_state = 0; |
501 | kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; | |
dc7d5527 | 502 | |
dfee3a7b JW |
503 | /* Make sure the above info reaches the primary CPU */ |
504 | smp_mb(); | |
505 | ||
506 | if (exception_level == 1) { | |
507 | if (raw_spin_trylock(&dbg_master_lock)) | |
508 | atomic_xchg(&kgdb_active, cpu); | |
6d906340 | 509 | goto cpu_master_loop; |
dfee3a7b | 510 | } |
6d906340 | 511 | |
dc7d5527 | 512 | /* |
62fae312 JW |
513 | * CPU will loop if it is a slave or request to become a kgdb |
514 | * master cpu and acquire the kgdb_active lock: | |
dc7d5527 | 515 | */ |
62fae312 | 516 | while (1) { |
dcc78711 JW |
517 | cpu_loop: |
518 | if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) { | |
519 | kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER; | |
520 | goto cpu_master_loop; | |
521 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { | |
dfee3a7b JW |
522 | if (raw_spin_trylock(&dbg_master_lock)) { |
523 | atomic_xchg(&kgdb_active, cpu); | |
62fae312 | 524 | break; |
dfee3a7b | 525 | } |
62fae312 | 526 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
dfee3a7b | 527 | if (!raw_spin_is_locked(&dbg_slave_lock)) |
62fae312 JW |
528 | goto return_normal; |
529 | } else { | |
530 | return_normal: | |
531 | /* Return to normal operation by executing any | |
532 | * hw breakpoint fixup. | |
533 | */ | |
534 | if (arch_kgdb_ops.correct_hw_break) | |
535 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
536 | if (trace_on) |
537 | tracing_on(); | |
dfee3a7b JW |
538 | kgdb_info[cpu].exception_state &= |
539 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
540 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 541 | smp_mb__before_atomic(); |
dfee3a7b | 542 | atomic_dec(&slaves_in_kgdb); |
16cdc628 | 543 | dbg_touch_watchdogs(); |
62fae312 JW |
544 | local_irq_restore(flags); |
545 | return 0; | |
546 | } | |
dc7d5527 | 547 | cpu_relax(); |
62fae312 | 548 | } |
dc7d5527 JW |
549 | |
550 | /* | |
028e7b17 | 551 | * For single stepping, try to only enter on the processor |
25985edc | 552 | * that was single stepping. To guard against a deadlock, the |
028e7b17 JW |
553 | * kernel will only try for the value of sstep_tries before |
554 | * giving up and continuing on. | |
dc7d5527 JW |
555 | */ |
556 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && | |
028e7b17 JW |
557 | (kgdb_info[cpu].task && |
558 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { | |
dc7d5527 | 559 | atomic_set(&kgdb_active, -1); |
dfee3a7b | 560 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 561 | dbg_touch_watchdogs(); |
dc7d5527 JW |
562 | local_irq_restore(flags); |
563 | ||
564 | goto acquirelock; | |
565 | } | |
566 | ||
567 | if (!kgdb_io_ready(1)) { | |
dcc78711 | 568 | kgdb_info[cpu].ret_state = 1; |
53197fc4 | 569 | goto kgdb_restore; /* No I/O connection, resume the system */ |
dc7d5527 JW |
570 | } |
571 | ||
572 | /* | |
573 | * Don't enter if we have hit a removed breakpoint. | |
574 | */ | |
575 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) | |
576 | goto kgdb_restore; | |
577 | ||
578 | /* Call the I/O driver's pre_exception routine */ | |
53197fc4 JW |
579 | if (dbg_io_ops->pre_exception) |
580 | dbg_io_ops->pre_exception(); | |
dc7d5527 | 581 | |
dc7d5527 JW |
582 | /* |
583 | * Get the passive CPU lock which will hold all the non-primary | |
584 | * CPU in a spin state while the debugger is active | |
585 | */ | |
dfee3a7b JW |
586 | if (!kgdb_single_step) |
587 | raw_spin_lock(&dbg_slave_lock); | |
dc7d5527 | 588 | |
56fb7093 | 589 | #ifdef CONFIG_SMP |
8daaa5f8 MT |
590 | /* If send_ready set, slaves are already waiting */ |
591 | if (ks->send_ready) | |
592 | atomic_set(ks->send_ready, 1); | |
593 | ||
56fb7093 | 594 | /* Signal the other CPUs to enter kgdb_wait() */ |
8daaa5f8 | 595 | else if ((!kgdb_single_step) && kgdb_do_roundup) |
56fb7093 JW |
596 | kgdb_roundup_cpus(flags); |
597 | #endif | |
598 | ||
dc7d5527 JW |
599 | /* |
600 | * Wait for the other CPUs to be notified and be waiting for us: | |
601 | */ | |
2d13bb64 | 602 | time_left = MSEC_PER_SEC; |
a1465d2f DT |
603 | while (kgdb_do_roundup && --time_left && |
604 | (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) != | |
605 | online_cpus) | |
2d13bb64 | 606 | udelay(1000); |
a1465d2f | 607 | if (!time_left) |
df0036d1 | 608 | pr_crit("Timed out waiting for secondary CPUs.\n"); |
dc7d5527 JW |
609 | |
610 | /* | |
611 | * At this point the primary processor is completely | |
612 | * in the debugger and all secondary CPUs are quiescent | |
613 | */ | |
dcc78711 | 614 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 | 615 | kgdb_single_step = 0; |
d7161a65 | 616 | kgdb_contthread = current; |
dc7d5527 | 617 | exception_level = 0; |
4da75b9c JW |
618 | trace_on = tracing_is_on(); |
619 | if (trace_on) | |
620 | tracing_off(); | |
dc7d5527 | 621 | |
dcc78711 JW |
622 | while (1) { |
623 | cpu_master_loop: | |
624 | if (dbg_kdb_mode) { | |
625 | kgdb_connected = 1; | |
626 | error = kdb_stub(ks); | |
3fa43aba JW |
627 | if (error == -1) |
628 | continue; | |
b0679c63 | 629 | kgdb_connected = 0; |
dcc78711 JW |
630 | } else { |
631 | error = gdb_serial_stub(ks); | |
632 | } | |
633 | ||
634 | if (error == DBG_PASS_EVENT) { | |
635 | dbg_kdb_mode = !dbg_kdb_mode; | |
dcc78711 | 636 | } else if (error == DBG_SWITCH_CPU_EVENT) { |
495363d3 JW |
637 | kgdb_info[dbg_switch_cpu].exception_state |= |
638 | DCPU_NEXT_MASTER; | |
dcc78711 JW |
639 | goto cpu_loop; |
640 | } else { | |
641 | kgdb_info[cpu].ret_state = error; | |
642 | break; | |
643 | } | |
644 | } | |
dc7d5527 JW |
645 | |
646 | /* Call the I/O driver's post_exception routine */ | |
53197fc4 JW |
647 | if (dbg_io_ops->post_exception) |
648 | dbg_io_ops->post_exception(); | |
dc7d5527 | 649 | |
d7161a65 | 650 | if (!kgdb_single_step) { |
dfee3a7b JW |
651 | raw_spin_unlock(&dbg_slave_lock); |
652 | /* Wait till all the CPUs have quit from the debugger. */ | |
653 | while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb)) | |
654 | cpu_relax(); | |
dc7d5527 JW |
655 | } |
656 | ||
657 | kgdb_restore: | |
028e7b17 JW |
658 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
659 | int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); | |
660 | if (kgdb_info[sstep_cpu].task) | |
661 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; | |
662 | else | |
663 | kgdb_sstep_pid = 0; | |
664 | } | |
c1bb9a9c DD |
665 | if (arch_kgdb_ops.correct_hw_break) |
666 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
667 | if (trace_on) |
668 | tracing_on(); | |
dfee3a7b JW |
669 | |
670 | kgdb_info[cpu].exception_state &= | |
671 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
672 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 673 | smp_mb__before_atomic(); |
dfee3a7b | 674 | atomic_dec(&masters_in_kgdb); |
dc7d5527 JW |
675 | /* Free kgdb_active */ |
676 | atomic_set(&kgdb_active, -1); | |
dfee3a7b | 677 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 678 | dbg_touch_watchdogs(); |
dc7d5527 JW |
679 | local_irq_restore(flags); |
680 | ||
dcc78711 | 681 | return kgdb_info[cpu].ret_state; |
dc7d5527 JW |
682 | } |
683 | ||
62fae312 JW |
684 | /* |
685 | * kgdb_handle_exception() - main entry point from a kernel exception | |
686 | * | |
687 | * Locking hierarchy: | |
688 | * interface locks, if any (begin_session) | |
689 | * kgdb lock (kgdb_active) | |
690 | */ | |
691 | int | |
692 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) | |
693 | { | |
694 | struct kgdb_state kgdb_var; | |
695 | struct kgdb_state *ks = &kgdb_var; | |
5a14fead AV |
696 | int ret = 0; |
697 | ||
698 | if (arch_kgdb_ops.enable_nmi) | |
699 | arch_kgdb_ops.enable_nmi(0); | |
5516fd7b CC |
700 | /* |
701 | * Avoid entering the debugger if we were triggered due to an oops | |
702 | * but panic_timeout indicates the system should automatically | |
703 | * reboot on panic. We don't want to get stuck waiting for input | |
704 | * on such systems, especially if its "just" an oops. | |
705 | */ | |
706 | if (signo != SIGTRAP && panic_timeout) | |
707 | return 1; | |
62fae312 | 708 | |
8daaa5f8 | 709 | memset(ks, 0, sizeof(struct kgdb_state)); |
62fae312 JW |
710 | ks->cpu = raw_smp_processor_id(); |
711 | ks->ex_vector = evector; | |
712 | ks->signo = signo; | |
62fae312 | 713 | ks->err_code = ecode; |
62fae312 JW |
714 | ks->linux_regs = regs; |
715 | ||
716 | if (kgdb_reenter_check(ks)) | |
5a14fead | 717 | goto out; /* Ouch, double exception ! */ |
dfee3a7b | 718 | if (kgdb_info[ks->cpu].enter_kgdb != 0) |
5a14fead | 719 | goto out; |
dfee3a7b | 720 | |
5a14fead AV |
721 | ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
722 | out: | |
723 | if (arch_kgdb_ops.enable_nmi) | |
724 | arch_kgdb_ops.enable_nmi(1); | |
725 | return ret; | |
62fae312 JW |
726 | } |
727 | ||
f30fed10 JW |
728 | /* |
729 | * GDB places a breakpoint at this function to know dynamically | |
730 | * loaded objects. It's not defined static so that only one instance with this | |
731 | * name exists in the kernel. | |
732 | */ | |
733 | ||
734 | static int module_event(struct notifier_block *self, unsigned long val, | |
735 | void *data) | |
736 | { | |
737 | return 0; | |
738 | } | |
739 | ||
740 | static struct notifier_block dbg_module_load_nb = { | |
741 | .notifier_call = module_event, | |
742 | }; | |
743 | ||
dc7d5527 JW |
744 | int kgdb_nmicallback(int cpu, void *regs) |
745 | { | |
746 | #ifdef CONFIG_SMP | |
62fae312 JW |
747 | struct kgdb_state kgdb_var; |
748 | struct kgdb_state *ks = &kgdb_var; | |
749 | ||
750 | memset(ks, 0, sizeof(struct kgdb_state)); | |
751 | ks->cpu = cpu; | |
752 | ks->linux_regs = regs; | |
753 | ||
dfee3a7b JW |
754 | if (kgdb_info[ks->cpu].enter_kgdb == 0 && |
755 | raw_spin_is_locked(&dbg_master_lock)) { | |
756 | kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); | |
dc7d5527 JW |
757 | return 0; |
758 | } | |
759 | #endif | |
760 | return 1; | |
761 | } | |
762 | ||
fc8b1374 MT |
763 | int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, |
764 | atomic_t *send_ready) | |
8daaa5f8 MT |
765 | { |
766 | #ifdef CONFIG_SMP | |
767 | if (!kgdb_io_ready(0) || !send_ready) | |
768 | return 1; | |
769 | ||
770 | if (kgdb_info[cpu].enter_kgdb == 0) { | |
771 | struct kgdb_state kgdb_var; | |
772 | struct kgdb_state *ks = &kgdb_var; | |
773 | ||
774 | memset(ks, 0, sizeof(struct kgdb_state)); | |
775 | ks->cpu = cpu; | |
776 | ks->ex_vector = trapnr; | |
777 | ks->signo = SIGTRAP; | |
fc8b1374 | 778 | ks->err_code = err_code; |
8daaa5f8 MT |
779 | ks->linux_regs = regs; |
780 | ks->send_ready = send_ready; | |
781 | kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); | |
782 | return 0; | |
783 | } | |
784 | #endif | |
785 | return 1; | |
786 | } | |
787 | ||
aabdc3b8 JW |
788 | static void kgdb_console_write(struct console *co, const char *s, |
789 | unsigned count) | |
dc7d5527 JW |
790 | { |
791 | unsigned long flags; | |
792 | ||
793 | /* If we're debugging, or KGDB has not connected, don't try | |
794 | * and print. */ | |
dcc78711 | 795 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) |
dc7d5527 JW |
796 | return; |
797 | ||
798 | local_irq_save(flags); | |
53197fc4 | 799 | gdbstub_msg_write(s, count); |
dc7d5527 JW |
800 | local_irq_restore(flags); |
801 | } | |
802 | ||
803 | static struct console kgdbcons = { | |
804 | .name = "kgdb", | |
805 | .write = kgdb_console_write, | |
806 | .flags = CON_PRINTBUFFER | CON_ENABLED, | |
807 | .index = -1, | |
808 | }; | |
809 | ||
810 | #ifdef CONFIG_MAGIC_SYSRQ | |
1495cc9d | 811 | static void sysrq_handle_dbg(int key) |
dc7d5527 | 812 | { |
53197fc4 | 813 | if (!dbg_io_ops) { |
0f16996c | 814 | pr_crit("ERROR: No KGDB I/O module available\n"); |
dc7d5527 JW |
815 | return; |
816 | } | |
dcc78711 JW |
817 | if (!kgdb_connected) { |
818 | #ifdef CONFIG_KGDB_KDB | |
819 | if (!dbg_kdb_mode) | |
0f16996c | 820 | pr_crit("KGDB or $3#33 for KDB\n"); |
dcc78711 | 821 | #else |
0f16996c | 822 | pr_crit("Entering KGDB\n"); |
dcc78711 JW |
823 | #endif |
824 | } | |
dc7d5527 JW |
825 | |
826 | kgdb_breakpoint(); | |
827 | } | |
828 | ||
53197fc4 JW |
829 | static struct sysrq_key_op sysrq_dbg_op = { |
830 | .handler = sysrq_handle_dbg, | |
f3456509 | 831 | .help_msg = "debug(g)", |
364b5b7b | 832 | .action_msg = "DEBUG", |
dc7d5527 JW |
833 | }; |
834 | #endif | |
835 | ||
4402c153 JW |
836 | static int kgdb_panic_event(struct notifier_block *self, |
837 | unsigned long val, | |
838 | void *data) | |
839 | { | |
5516fd7b CC |
840 | /* |
841 | * Avoid entering the debugger if we were triggered due to a panic | |
842 | * We don't want to get stuck waiting for input from user in such case. | |
843 | * panic_timeout indicates the system should automatically | |
844 | * reboot on panic. | |
845 | */ | |
846 | if (panic_timeout) | |
847 | return NOTIFY_DONE; | |
848 | ||
4402c153 JW |
849 | if (dbg_kdb_mode) |
850 | kdb_printf("PANIC: %s\n", (char *)data); | |
851 | kgdb_breakpoint(); | |
852 | return NOTIFY_DONE; | |
853 | } | |
854 | ||
855 | static struct notifier_block kgdb_panic_event_nb = { | |
856 | .notifier_call = kgdb_panic_event, | |
857 | .priority = INT_MAX, | |
858 | }; | |
859 | ||
0b4b3827 JW |
860 | void __weak kgdb_arch_late(void) |
861 | { | |
862 | } | |
863 | ||
864 | void __init dbg_late_init(void) | |
865 | { | |
866 | dbg_is_early = false; | |
867 | if (kgdb_io_module_registered) | |
868 | kgdb_arch_late(); | |
869 | kdb_init(KDB_INIT_FULL); | |
870 | } | |
871 | ||
2366e047 JW |
872 | static int |
873 | dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x) | |
874 | { | |
bec4d62e JW |
875 | /* |
876 | * Take the following action on reboot notify depending on value: | |
877 | * 1 == Enter debugger | |
878 | * 0 == [the default] detatch debug client | |
879 | * -1 == Do nothing... and use this until the board resets | |
880 | */ | |
881 | switch (kgdbreboot) { | |
882 | case 1: | |
883 | kgdb_breakpoint(); | |
884 | case -1: | |
885 | goto done; | |
886 | } | |
2366e047 JW |
887 | if (!dbg_kdb_mode) |
888 | gdbstub_exit(code); | |
bec4d62e | 889 | done: |
2366e047 JW |
890 | return NOTIFY_DONE; |
891 | } | |
892 | ||
893 | static struct notifier_block dbg_reboot_notifier = { | |
894 | .notifier_call = dbg_notify_reboot, | |
895 | .next = NULL, | |
896 | .priority = INT_MAX, | |
897 | }; | |
898 | ||
dc7d5527 JW |
899 | static void kgdb_register_callbacks(void) |
900 | { | |
901 | if (!kgdb_io_module_registered) { | |
902 | kgdb_io_module_registered = 1; | |
903 | kgdb_arch_init(); | |
0b4b3827 JW |
904 | if (!dbg_is_early) |
905 | kgdb_arch_late(); | |
f30fed10 | 906 | register_module_notifier(&dbg_module_load_nb); |
2366e047 | 907 | register_reboot_notifier(&dbg_reboot_notifier); |
4402c153 JW |
908 | atomic_notifier_chain_register(&panic_notifier_list, |
909 | &kgdb_panic_event_nb); | |
dc7d5527 | 910 | #ifdef CONFIG_MAGIC_SYSRQ |
53197fc4 | 911 | register_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
912 | #endif |
913 | if (kgdb_use_con && !kgdb_con_registered) { | |
914 | register_console(&kgdbcons); | |
915 | kgdb_con_registered = 1; | |
916 | } | |
917 | } | |
918 | } | |
919 | ||
920 | static void kgdb_unregister_callbacks(void) | |
921 | { | |
922 | /* | |
923 | * When this routine is called KGDB should unregister from the | |
924 | * panic handler and clean up, making sure it is not handling any | |
925 | * break exceptions at the time. | |
926 | */ | |
927 | if (kgdb_io_module_registered) { | |
928 | kgdb_io_module_registered = 0; | |
2366e047 | 929 | unregister_reboot_notifier(&dbg_reboot_notifier); |
f30fed10 | 930 | unregister_module_notifier(&dbg_module_load_nb); |
4402c153 JW |
931 | atomic_notifier_chain_unregister(&panic_notifier_list, |
932 | &kgdb_panic_event_nb); | |
dc7d5527 JW |
933 | kgdb_arch_exit(); |
934 | #ifdef CONFIG_MAGIC_SYSRQ | |
53197fc4 | 935 | unregister_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
936 | #endif |
937 | if (kgdb_con_registered) { | |
938 | unregister_console(&kgdbcons); | |
939 | kgdb_con_registered = 0; | |
940 | } | |
941 | } | |
942 | } | |
943 | ||
1cee5e35 JW |
944 | /* |
945 | * There are times a tasklet needs to be used vs a compiled in | |
946 | * break point so as to cause an exception outside a kgdb I/O module, | |
947 | * such as is the case with kgdboe, where calling a breakpoint in the | |
948 | * I/O driver itself would be fatal. | |
949 | */ | |
950 | static void kgdb_tasklet_bpt(unsigned long ing) | |
951 | { | |
952 | kgdb_breakpoint(); | |
953 | atomic_set(&kgdb_break_tasklet_var, 0); | |
954 | } | |
955 | ||
956 | static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0); | |
957 | ||
958 | void kgdb_schedule_breakpoint(void) | |
959 | { | |
960 | if (atomic_read(&kgdb_break_tasklet_var) || | |
961 | atomic_read(&kgdb_active) != -1 || | |
962 | atomic_read(&kgdb_setting_breakpoint)) | |
963 | return; | |
964 | atomic_inc(&kgdb_break_tasklet_var); | |
965 | tasklet_schedule(&kgdb_tasklet_breakpoint); | |
966 | } | |
967 | EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint); | |
968 | ||
dc7d5527 JW |
969 | static void kgdb_initial_breakpoint(void) |
970 | { | |
971 | kgdb_break_asap = 0; | |
972 | ||
0f16996c | 973 | pr_crit("Waiting for connection from remote gdb...\n"); |
dc7d5527 JW |
974 | kgdb_breakpoint(); |
975 | } | |
976 | ||
977 | /** | |
737a460f | 978 | * kgdb_register_io_module - register KGDB IO module |
53197fc4 | 979 | * @new_dbg_io_ops: the io ops vector |
dc7d5527 JW |
980 | * |
981 | * Register it with the KGDB core. | |
982 | */ | |
53197fc4 | 983 | int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
dc7d5527 JW |
984 | { |
985 | int err; | |
986 | ||
987 | spin_lock(&kgdb_registration_lock); | |
988 | ||
53197fc4 | 989 | if (dbg_io_ops) { |
dc7d5527 JW |
990 | spin_unlock(&kgdb_registration_lock); |
991 | ||
0f16996c | 992 | pr_err("Another I/O driver is already registered with KGDB\n"); |
dc7d5527 JW |
993 | return -EBUSY; |
994 | } | |
995 | ||
53197fc4 JW |
996 | if (new_dbg_io_ops->init) { |
997 | err = new_dbg_io_ops->init(); | |
dc7d5527 JW |
998 | if (err) { |
999 | spin_unlock(&kgdb_registration_lock); | |
1000 | return err; | |
1001 | } | |
1002 | } | |
1003 | ||
53197fc4 | 1004 | dbg_io_ops = new_dbg_io_ops; |
dc7d5527 JW |
1005 | |
1006 | spin_unlock(&kgdb_registration_lock); | |
1007 | ||
0f16996c | 1008 | pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name); |
dc7d5527 JW |
1009 | |
1010 | /* Arm KGDB now. */ | |
1011 | kgdb_register_callbacks(); | |
1012 | ||
1013 | if (kgdb_break_asap) | |
1014 | kgdb_initial_breakpoint(); | |
1015 | ||
1016 | return 0; | |
1017 | } | |
1018 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); | |
1019 | ||
1020 | /** | |
1021 | * kkgdb_unregister_io_module - unregister KGDB IO module | |
53197fc4 | 1022 | * @old_dbg_io_ops: the io ops vector |
dc7d5527 JW |
1023 | * |
1024 | * Unregister it with the KGDB core. | |
1025 | */ | |
53197fc4 | 1026 | void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
dc7d5527 JW |
1027 | { |
1028 | BUG_ON(kgdb_connected); | |
1029 | ||
1030 | /* | |
1031 | * KGDB is no longer able to communicate out, so | |
1032 | * unregister our callbacks and reset state. | |
1033 | */ | |
1034 | kgdb_unregister_callbacks(); | |
1035 | ||
1036 | spin_lock(&kgdb_registration_lock); | |
1037 | ||
53197fc4 JW |
1038 | WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); |
1039 | dbg_io_ops = NULL; | |
dc7d5527 JW |
1040 | |
1041 | spin_unlock(&kgdb_registration_lock); | |
1042 | ||
0f16996c | 1043 | pr_info("Unregistered I/O driver %s, debugger disabled\n", |
53197fc4 | 1044 | old_dbg_io_ops->name); |
dc7d5527 JW |
1045 | } |
1046 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); | |
1047 | ||
dcc78711 JW |
1048 | int dbg_io_get_char(void) |
1049 | { | |
1050 | int ret = dbg_io_ops->read_char(); | |
f5316b4a JW |
1051 | if (ret == NO_POLL_CHAR) |
1052 | return -1; | |
dcc78711 JW |
1053 | if (!dbg_kdb_mode) |
1054 | return ret; | |
1055 | if (ret == 127) | |
1056 | return 8; | |
1057 | return ret; | |
1058 | } | |
1059 | ||
dc7d5527 JW |
1060 | /** |
1061 | * kgdb_breakpoint - generate breakpoint exception | |
1062 | * | |
1063 | * This function will generate a breakpoint exception. It is used at the | |
1064 | * beginning of a program to sync up with a debugger and can be used | |
1065 | * otherwise as a quick means to stop program execution and "break" into | |
1066 | * the debugger. | |
1067 | */ | |
d498d4b4 | 1068 | noinline void kgdb_breakpoint(void) |
dc7d5527 | 1069 | { |
ae6bf53e | 1070 | atomic_inc(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1071 | wmb(); /* Sync point before breakpoint */ |
1072 | arch_kgdb_breakpoint(); | |
1073 | wmb(); /* Sync point after breakpoint */ | |
ae6bf53e | 1074 | atomic_dec(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1075 | } |
1076 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); | |
1077 | ||
1078 | static int __init opt_kgdb_wait(char *str) | |
1079 | { | |
1080 | kgdb_break_asap = 1; | |
1081 | ||
dcc78711 | 1082 | kdb_init(KDB_INIT_EARLY); |
dc7d5527 JW |
1083 | if (kgdb_io_module_registered) |
1084 | kgdb_initial_breakpoint(); | |
1085 | ||
1086 | return 0; | |
1087 | } | |
1088 | ||
1089 | early_param("kgdbwait", opt_kgdb_wait); |