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 | */ | |
30 | #include <linux/pid_namespace.h> | |
7c3078b6 | 31 | #include <linux/clocksource.h> |
16559ae4 | 32 | #include <linux/serial_core.h> |
dc7d5527 JW |
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> | |
dc7d5527 JW |
41 | #include <linux/string.h> |
42 | #include <linux/delay.h> | |
43 | #include <linux/sched.h> | |
44 | #include <linux/sysrq.h> | |
2366e047 | 45 | #include <linux/reboot.h> |
dc7d5527 JW |
46 | #include <linux/init.h> |
47 | #include <linux/kgdb.h> | |
dcc78711 | 48 | #include <linux/kdb.h> |
dc7d5527 JW |
49 | #include <linux/pid.h> |
50 | #include <linux/smp.h> | |
51 | #include <linux/mm.h> | |
615d6e87 | 52 | #include <linux/vmacache.h> |
fb70b588 | 53 | #include <linux/rcupdate.h> |
dc7d5527 JW |
54 | |
55 | #include <asm/cacheflush.h> | |
56 | #include <asm/byteorder.h> | |
60063497 | 57 | #include <linux/atomic.h> |
dc7d5527 | 58 | |
53197fc4 | 59 | #include "debug_core.h" |
dc7d5527 | 60 | |
53197fc4 | 61 | static int kgdb_break_asap; |
62fae312 | 62 | |
53197fc4 | 63 | struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
dc7d5527 JW |
64 | |
65 | /** | |
66 | * kgdb_connected - Is a host GDB connected to us? | |
67 | */ | |
68 | int kgdb_connected; | |
69 | EXPORT_SYMBOL_GPL(kgdb_connected); | |
70 | ||
71 | /* All the KGDB handlers are installed */ | |
f503b5ae | 72 | int kgdb_io_module_registered; |
dc7d5527 JW |
73 | |
74 | /* Guard for recursive entry */ | |
75 | static int exception_level; | |
76 | ||
53197fc4 | 77 | struct kgdb_io *dbg_io_ops; |
dc7d5527 JW |
78 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
79 | ||
bec4d62e JW |
80 | /* Action for the reboot notifiter, a global allow kdb to change it */ |
81 | static int kgdbreboot; | |
dc7d5527 JW |
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; | |
0b4b3827 JW |
86 | /* Flag for alternate operations for early debugging */ |
87 | bool dbg_is_early = true; | |
dcc78711 JW |
88 | /* Next cpu to become the master debug core */ |
89 | int dbg_switch_cpu; | |
90 | ||
91 | /* Use kdb or gdbserver mode */ | |
a0de055c | 92 | int dbg_kdb_mode = 1; |
dc7d5527 JW |
93 | |
94 | static int __init opt_kgdb_con(char *str) | |
95 | { | |
96 | kgdb_use_con = 1; | |
97 | return 0; | |
98 | } | |
99 | ||
100 | early_param("kgdbcon", opt_kgdb_con); | |
101 | ||
102 | module_param(kgdb_use_con, int, 0644); | |
bec4d62e | 103 | module_param(kgdbreboot, int, 0644); |
dc7d5527 JW |
104 | |
105 | /* | |
106 | * Holds information about breakpoints in a kernel. These breakpoints are | |
107 | * added and removed by gdb. | |
108 | */ | |
109 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { | |
110 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } | |
111 | }; | |
112 | ||
113 | /* | |
114 | * The CPU# of the active CPU, or -1 if none: | |
115 | */ | |
116 | atomic_t kgdb_active = ATOMIC_INIT(-1); | |
dcc78711 | 117 | EXPORT_SYMBOL_GPL(kgdb_active); |
dfee3a7b JW |
118 | static DEFINE_RAW_SPINLOCK(dbg_master_lock); |
119 | static DEFINE_RAW_SPINLOCK(dbg_slave_lock); | |
dc7d5527 JW |
120 | |
121 | /* | |
122 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early | |
123 | * bootup code (which might not have percpu set up yet): | |
124 | */ | |
dfee3a7b JW |
125 | static atomic_t masters_in_kgdb; |
126 | static atomic_t slaves_in_kgdb; | |
1cee5e35 | 127 | static atomic_t kgdb_break_tasklet_var; |
dc7d5527 JW |
128 | atomic_t kgdb_setting_breakpoint; |
129 | ||
130 | struct task_struct *kgdb_usethread; | |
131 | struct task_struct *kgdb_contthread; | |
132 | ||
133 | int kgdb_single_step; | |
53197fc4 | 134 | static pid_t kgdb_sstep_pid; |
dc7d5527 JW |
135 | |
136 | /* to keep track of the CPU which is doing the single stepping*/ | |
137 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); | |
138 | ||
139 | /* | |
140 | * If you are debugging a problem where roundup (the collection of | |
141 | * all other CPUs) is a problem [this should be extremely rare], | |
142 | * then use the nokgdbroundup option to avoid roundup. In that case | |
143 | * the other CPUs might interfere with your debugging context, so | |
144 | * use this with care: | |
145 | */ | |
688b744d | 146 | static int kgdb_do_roundup = 1; |
dc7d5527 JW |
147 | |
148 | static int __init opt_nokgdbroundup(char *str) | |
149 | { | |
150 | kgdb_do_roundup = 0; | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | early_param("nokgdbroundup", opt_nokgdbroundup); | |
156 | ||
157 | /* | |
158 | * Finally, some KGDB code :-) | |
159 | */ | |
160 | ||
161 | /* | |
162 | * Weak aliases for breakpoint management, | |
163 | * can be overriden by architectures when needed: | |
164 | */ | |
98b54aa1 | 165 | int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 JW |
166 | { |
167 | int err; | |
168 | ||
98b54aa1 JW |
169 | err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, |
170 | BREAK_INSTR_SIZE); | |
dc7d5527 JW |
171 | if (err) |
172 | return err; | |
98b54aa1 JW |
173 | err = probe_kernel_write((char *)bpt->bpt_addr, |
174 | arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); | |
175 | return err; | |
dc7d5527 JW |
176 | } |
177 | ||
98b54aa1 | 178 | int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
dc7d5527 | 179 | { |
98b54aa1 JW |
180 | return probe_kernel_write((char *)bpt->bpt_addr, |
181 | (char *)bpt->saved_instr, BREAK_INSTR_SIZE); | |
dc7d5527 JW |
182 | } |
183 | ||
a9b60bf4 JW |
184 | int __weak kgdb_validate_break_address(unsigned long addr) |
185 | { | |
98b54aa1 | 186 | struct kgdb_bkpt tmp; |
a9b60bf4 | 187 | int err; |
98b54aa1 | 188 | /* Validate setting the breakpoint and then removing it. If the |
a9b60bf4 JW |
189 | * remove fails, the kernel needs to emit a bad message because we |
190 | * are deep trouble not being able to put things back the way we | |
191 | * found them. | |
192 | */ | |
98b54aa1 JW |
193 | tmp.bpt_addr = addr; |
194 | err = kgdb_arch_set_breakpoint(&tmp); | |
a9b60bf4 JW |
195 | if (err) |
196 | return err; | |
98b54aa1 | 197 | err = kgdb_arch_remove_breakpoint(&tmp); |
a9b60bf4 JW |
198 | if (err) |
199 | printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " | |
200 | "memory destroyed at: %lx", addr); | |
201 | return err; | |
202 | } | |
203 | ||
dc7d5527 JW |
204 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
205 | { | |
206 | return instruction_pointer(regs); | |
207 | } | |
208 | ||
209 | int __weak kgdb_arch_init(void) | |
210 | { | |
211 | return 0; | |
212 | } | |
213 | ||
b4b8ac52 JW |
214 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
215 | { | |
216 | return 0; | |
217 | } | |
218 | ||
dc7d5527 JW |
219 | /* |
220 | * Some architectures need cache flushes when we set/clear a | |
221 | * breakpoint: | |
222 | */ | |
223 | static void kgdb_flush_swbreak_addr(unsigned long addr) | |
224 | { | |
225 | if (!CACHE_FLUSH_IS_SAFE) | |
226 | return; | |
227 | ||
615d6e87 DB |
228 | if (current->mm) { |
229 | int i; | |
230 | ||
231 | for (i = 0; i < VMACACHE_SIZE; i++) { | |
232 | if (!current->vmacache[i]) | |
233 | continue; | |
234 | flush_cache_range(current->vmacache[i], | |
235 | addr, addr + BREAK_INSTR_SIZE); | |
236 | } | |
dc7d5527 | 237 | } |
615d6e87 | 238 | |
1a9a3e76 JW |
239 | /* Force flush instruction cache if it was outside the mm */ |
240 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); | |
dc7d5527 JW |
241 | } |
242 | ||
243 | /* | |
244 | * SW breakpoint management: | |
245 | */ | |
53197fc4 | 246 | int dbg_activate_sw_breakpoints(void) |
dc7d5527 | 247 | { |
7f8b7ed6 JW |
248 | int error; |
249 | int ret = 0; | |
dc7d5527 JW |
250 | int i; |
251 | ||
252 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
253 | if (kgdb_break[i].state != BP_SET) | |
254 | continue; | |
255 | ||
98b54aa1 | 256 | error = kgdb_arch_set_breakpoint(&kgdb_break[i]); |
7f8b7ed6 JW |
257 | if (error) { |
258 | ret = error; | |
98b54aa1 JW |
259 | printk(KERN_INFO "KGDB: BP install failed: %lx", |
260 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
261 | continue; |
262 | } | |
dc7d5527 | 263 | |
98b54aa1 | 264 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
265 | kgdb_break[i].state = BP_ACTIVE; |
266 | } | |
7f8b7ed6 | 267 | return ret; |
dc7d5527 JW |
268 | } |
269 | ||
53197fc4 | 270 | int dbg_set_sw_break(unsigned long addr) |
dc7d5527 JW |
271 | { |
272 | int err = kgdb_validate_break_address(addr); | |
273 | int breakno = -1; | |
274 | int i; | |
275 | ||
276 | if (err) | |
277 | return err; | |
278 | ||
279 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
280 | if ((kgdb_break[i].state == BP_SET) && | |
281 | (kgdb_break[i].bpt_addr == addr)) | |
282 | return -EEXIST; | |
283 | } | |
284 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
285 | if (kgdb_break[i].state == BP_REMOVED && | |
286 | kgdb_break[i].bpt_addr == addr) { | |
287 | breakno = i; | |
288 | break; | |
289 | } | |
290 | } | |
291 | ||
292 | if (breakno == -1) { | |
293 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
294 | if (kgdb_break[i].state == BP_UNDEFINED) { | |
295 | breakno = i; | |
296 | break; | |
297 | } | |
298 | } | |
299 | } | |
300 | ||
301 | if (breakno == -1) | |
302 | return -E2BIG; | |
303 | ||
304 | kgdb_break[breakno].state = BP_SET; | |
305 | kgdb_break[breakno].type = BP_BREAKPOINT; | |
306 | kgdb_break[breakno].bpt_addr = addr; | |
307 | ||
308 | return 0; | |
309 | } | |
310 | ||
dcc78711 | 311 | int dbg_deactivate_sw_breakpoints(void) |
dc7d5527 | 312 | { |
7f8b7ed6 JW |
313 | int error; |
314 | int ret = 0; | |
dc7d5527 JW |
315 | int i; |
316 | ||
317 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
318 | if (kgdb_break[i].state != BP_ACTIVE) | |
319 | continue; | |
98b54aa1 | 320 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
7f8b7ed6 | 321 | if (error) { |
98b54aa1 JW |
322 | printk(KERN_INFO "KGDB: BP remove failed: %lx\n", |
323 | kgdb_break[i].bpt_addr); | |
7f8b7ed6 JW |
324 | ret = error; |
325 | } | |
dc7d5527 | 326 | |
98b54aa1 | 327 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
dc7d5527 JW |
328 | kgdb_break[i].state = BP_SET; |
329 | } | |
7f8b7ed6 | 330 | return ret; |
dc7d5527 JW |
331 | } |
332 | ||
53197fc4 | 333 | int dbg_remove_sw_break(unsigned long addr) |
dc7d5527 JW |
334 | { |
335 | int i; | |
336 | ||
337 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
338 | if ((kgdb_break[i].state == BP_SET) && | |
339 | (kgdb_break[i].bpt_addr == addr)) { | |
340 | kgdb_break[i].state = BP_REMOVED; | |
341 | return 0; | |
342 | } | |
343 | } | |
344 | return -ENOENT; | |
345 | } | |
346 | ||
347 | int kgdb_isremovedbreak(unsigned long addr) | |
348 | { | |
349 | int i; | |
350 | ||
351 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
352 | if ((kgdb_break[i].state == BP_REMOVED) && | |
353 | (kgdb_break[i].bpt_addr == addr)) | |
354 | return 1; | |
355 | } | |
356 | return 0; | |
357 | } | |
358 | ||
53197fc4 | 359 | int dbg_remove_all_break(void) |
dc7d5527 | 360 | { |
dc7d5527 JW |
361 | int error; |
362 | int i; | |
363 | ||
364 | /* Clear memory breakpoints. */ | |
365 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
737a460f JW |
366 | if (kgdb_break[i].state != BP_ACTIVE) |
367 | goto setundefined; | |
98b54aa1 | 368 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
dc7d5527 | 369 | if (error) |
737a460f | 370 | printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n", |
98b54aa1 | 371 | kgdb_break[i].bpt_addr); |
737a460f JW |
372 | setundefined: |
373 | kgdb_break[i].state = BP_UNDEFINED; | |
dc7d5527 JW |
374 | } |
375 | ||
376 | /* Clear hardware breakpoints. */ | |
377 | if (arch_kgdb_ops.remove_all_hw_break) | |
378 | arch_kgdb_ops.remove_all_hw_break(); | |
379 | ||
380 | return 0; | |
381 | } | |
382 | ||
dc7d5527 JW |
383 | /* |
384 | * Return true if there is a valid kgdb I/O module. Also if no | |
385 | * debugger is attached a message can be printed to the console about | |
386 | * waiting for the debugger to attach. | |
387 | * | |
388 | * The print_wait argument is only to be true when called from inside | |
389 | * the core kgdb_handle_exception, because it will wait for the | |
390 | * debugger to attach. | |
391 | */ | |
392 | static int kgdb_io_ready(int print_wait) | |
393 | { | |
53197fc4 | 394 | if (!dbg_io_ops) |
dc7d5527 JW |
395 | return 0; |
396 | if (kgdb_connected) | |
397 | return 1; | |
398 | if (atomic_read(&kgdb_setting_breakpoint)) | |
399 | return 1; | |
dcc78711 JW |
400 | if (print_wait) { |
401 | #ifdef CONFIG_KGDB_KDB | |
402 | if (!dbg_kdb_mode) | |
403 | printk(KERN_CRIT "KGDB: waiting... or $3#33 for KDB\n"); | |
404 | #else | |
dc7d5527 | 405 | printk(KERN_CRIT "KGDB: Waiting for remote debugger\n"); |
dcc78711 JW |
406 | #endif |
407 | } | |
dc7d5527 JW |
408 | return 1; |
409 | } | |
410 | ||
dc7d5527 JW |
411 | static int kgdb_reenter_check(struct kgdb_state *ks) |
412 | { | |
413 | unsigned long addr; | |
414 | ||
415 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) | |
416 | return 0; | |
417 | ||
418 | /* Panic on recursive debugger calls: */ | |
419 | exception_level++; | |
420 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); | |
dcc78711 | 421 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 JW |
422 | |
423 | /* | |
424 | * If the break point removed ok at the place exception | |
425 | * occurred, try to recover and print a warning to the end | |
426 | * user because the user planted a breakpoint in a place that | |
427 | * KGDB needs in order to function. | |
428 | */ | |
53197fc4 | 429 | if (dbg_remove_sw_break(addr) == 0) { |
dc7d5527 JW |
430 | exception_level = 0; |
431 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); | |
53197fc4 | 432 | dbg_activate_sw_breakpoints(); |
67baf94c JW |
433 | printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n", |
434 | addr); | |
dc7d5527 JW |
435 | WARN_ON_ONCE(1); |
436 | ||
437 | return 1; | |
438 | } | |
53197fc4 | 439 | dbg_remove_all_break(); |
dc7d5527 JW |
440 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
441 | ||
442 | if (exception_level > 1) { | |
443 | dump_stack(); | |
444 | panic("Recursive entry to debugger"); | |
445 | } | |
446 | ||
447 | printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n"); | |
6d906340 JW |
448 | #ifdef CONFIG_KGDB_KDB |
449 | /* Allow kdb to debug itself one level */ | |
450 | return 0; | |
451 | #endif | |
dc7d5527 JW |
452 | dump_stack(); |
453 | panic("Recursive entry to debugger"); | |
454 | ||
455 | return 1; | |
456 | } | |
457 | ||
16cdc628 JW |
458 | static void dbg_touch_watchdogs(void) |
459 | { | |
460 | touch_softlockup_watchdog_sync(); | |
461 | clocksource_touch_watchdog(); | |
fb70b588 | 462 | rcu_cpu_stall_reset(); |
16cdc628 JW |
463 | } |
464 | ||
dfee3a7b JW |
465 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, |
466 | int exception_state) | |
dc7d5527 | 467 | { |
dc7d5527 | 468 | unsigned long flags; |
028e7b17 | 469 | int sstep_tries = 100; |
dcc78711 | 470 | int error; |
dfee3a7b | 471 | int cpu; |
4da75b9c | 472 | int trace_on = 0; |
dfee3a7b | 473 | int online_cpus = num_online_cpus(); |
c1bb9a9c | 474 | |
dfee3a7b JW |
475 | kgdb_info[ks->cpu].enter_kgdb++; |
476 | kgdb_info[ks->cpu].exception_state |= exception_state; | |
477 | ||
478 | if (exception_state == DCPU_WANT_MASTER) | |
479 | atomic_inc(&masters_in_kgdb); | |
480 | else | |
481 | atomic_inc(&slaves_in_kgdb); | |
d7ba979d DD |
482 | |
483 | if (arch_kgdb_ops.disable_hw_break) | |
484 | arch_kgdb_ops.disable_hw_break(regs); | |
c1bb9a9c | 485 | |
dc7d5527 JW |
486 | acquirelock: |
487 | /* | |
488 | * Interrupts will be restored by the 'trap return' code, except when | |
489 | * single stepping. | |
490 | */ | |
491 | local_irq_save(flags); | |
492 | ||
62fae312 JW |
493 | cpu = ks->cpu; |
494 | kgdb_info[cpu].debuggerinfo = regs; | |
495 | kgdb_info[cpu].task = current; | |
dcc78711 JW |
496 | kgdb_info[cpu].ret_state = 0; |
497 | kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; | |
dc7d5527 | 498 | |
dfee3a7b JW |
499 | /* Make sure the above info reaches the primary CPU */ |
500 | smp_mb(); | |
501 | ||
502 | if (exception_level == 1) { | |
503 | if (raw_spin_trylock(&dbg_master_lock)) | |
504 | atomic_xchg(&kgdb_active, cpu); | |
6d906340 | 505 | goto cpu_master_loop; |
dfee3a7b | 506 | } |
6d906340 | 507 | |
dc7d5527 | 508 | /* |
62fae312 JW |
509 | * CPU will loop if it is a slave or request to become a kgdb |
510 | * master cpu and acquire the kgdb_active lock: | |
dc7d5527 | 511 | */ |
62fae312 | 512 | while (1) { |
dcc78711 JW |
513 | cpu_loop: |
514 | if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) { | |
515 | kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER; | |
516 | goto cpu_master_loop; | |
517 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { | |
dfee3a7b JW |
518 | if (raw_spin_trylock(&dbg_master_lock)) { |
519 | atomic_xchg(&kgdb_active, cpu); | |
62fae312 | 520 | break; |
dfee3a7b | 521 | } |
62fae312 | 522 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
dfee3a7b | 523 | if (!raw_spin_is_locked(&dbg_slave_lock)) |
62fae312 JW |
524 | goto return_normal; |
525 | } else { | |
526 | return_normal: | |
527 | /* Return to normal operation by executing any | |
528 | * hw breakpoint fixup. | |
529 | */ | |
530 | if (arch_kgdb_ops.correct_hw_break) | |
531 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
532 | if (trace_on) |
533 | tracing_on(); | |
dfee3a7b JW |
534 | kgdb_info[cpu].exception_state &= |
535 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
536 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 537 | smp_mb__before_atomic(); |
dfee3a7b | 538 | atomic_dec(&slaves_in_kgdb); |
16cdc628 | 539 | dbg_touch_watchdogs(); |
62fae312 JW |
540 | local_irq_restore(flags); |
541 | return 0; | |
542 | } | |
dc7d5527 | 543 | cpu_relax(); |
62fae312 | 544 | } |
dc7d5527 JW |
545 | |
546 | /* | |
028e7b17 | 547 | * For single stepping, try to only enter on the processor |
25985edc | 548 | * that was single stepping. To guard against a deadlock, the |
028e7b17 JW |
549 | * kernel will only try for the value of sstep_tries before |
550 | * giving up and continuing on. | |
dc7d5527 JW |
551 | */ |
552 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && | |
028e7b17 JW |
553 | (kgdb_info[cpu].task && |
554 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { | |
dc7d5527 | 555 | atomic_set(&kgdb_active, -1); |
dfee3a7b | 556 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 557 | dbg_touch_watchdogs(); |
dc7d5527 JW |
558 | local_irq_restore(flags); |
559 | ||
560 | goto acquirelock; | |
561 | } | |
562 | ||
563 | if (!kgdb_io_ready(1)) { | |
dcc78711 | 564 | kgdb_info[cpu].ret_state = 1; |
53197fc4 | 565 | goto kgdb_restore; /* No I/O connection, resume the system */ |
dc7d5527 JW |
566 | } |
567 | ||
568 | /* | |
569 | * Don't enter if we have hit a removed breakpoint. | |
570 | */ | |
571 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) | |
572 | goto kgdb_restore; | |
573 | ||
574 | /* Call the I/O driver's pre_exception routine */ | |
53197fc4 JW |
575 | if (dbg_io_ops->pre_exception) |
576 | dbg_io_ops->pre_exception(); | |
dc7d5527 | 577 | |
dc7d5527 JW |
578 | /* |
579 | * Get the passive CPU lock which will hold all the non-primary | |
580 | * CPU in a spin state while the debugger is active | |
581 | */ | |
dfee3a7b JW |
582 | if (!kgdb_single_step) |
583 | raw_spin_lock(&dbg_slave_lock); | |
dc7d5527 | 584 | |
56fb7093 | 585 | #ifdef CONFIG_SMP |
8daaa5f8 MT |
586 | /* If send_ready set, slaves are already waiting */ |
587 | if (ks->send_ready) | |
588 | atomic_set(ks->send_ready, 1); | |
589 | ||
56fb7093 | 590 | /* Signal the other CPUs to enter kgdb_wait() */ |
8daaa5f8 | 591 | else if ((!kgdb_single_step) && kgdb_do_roundup) |
56fb7093 JW |
592 | kgdb_roundup_cpus(flags); |
593 | #endif | |
594 | ||
dc7d5527 JW |
595 | /* |
596 | * Wait for the other CPUs to be notified and be waiting for us: | |
597 | */ | |
dfee3a7b JW |
598 | while (kgdb_do_roundup && (atomic_read(&masters_in_kgdb) + |
599 | atomic_read(&slaves_in_kgdb)) != online_cpus) | |
600 | cpu_relax(); | |
dc7d5527 JW |
601 | |
602 | /* | |
603 | * At this point the primary processor is completely | |
604 | * in the debugger and all secondary CPUs are quiescent | |
605 | */ | |
dcc78711 | 606 | dbg_deactivate_sw_breakpoints(); |
dc7d5527 | 607 | kgdb_single_step = 0; |
d7161a65 | 608 | kgdb_contthread = current; |
dc7d5527 | 609 | exception_level = 0; |
4da75b9c JW |
610 | trace_on = tracing_is_on(); |
611 | if (trace_on) | |
612 | tracing_off(); | |
dc7d5527 | 613 | |
dcc78711 JW |
614 | while (1) { |
615 | cpu_master_loop: | |
616 | if (dbg_kdb_mode) { | |
617 | kgdb_connected = 1; | |
618 | error = kdb_stub(ks); | |
3fa43aba JW |
619 | if (error == -1) |
620 | continue; | |
b0679c63 | 621 | kgdb_connected = 0; |
dcc78711 JW |
622 | } else { |
623 | error = gdb_serial_stub(ks); | |
624 | } | |
625 | ||
626 | if (error == DBG_PASS_EVENT) { | |
627 | dbg_kdb_mode = !dbg_kdb_mode; | |
dcc78711 | 628 | } else if (error == DBG_SWITCH_CPU_EVENT) { |
495363d3 JW |
629 | kgdb_info[dbg_switch_cpu].exception_state |= |
630 | DCPU_NEXT_MASTER; | |
dcc78711 JW |
631 | goto cpu_loop; |
632 | } else { | |
633 | kgdb_info[cpu].ret_state = error; | |
634 | break; | |
635 | } | |
636 | } | |
dc7d5527 JW |
637 | |
638 | /* Call the I/O driver's post_exception routine */ | |
53197fc4 JW |
639 | if (dbg_io_ops->post_exception) |
640 | dbg_io_ops->post_exception(); | |
dc7d5527 | 641 | |
d7161a65 | 642 | if (!kgdb_single_step) { |
dfee3a7b JW |
643 | raw_spin_unlock(&dbg_slave_lock); |
644 | /* Wait till all the CPUs have quit from the debugger. */ | |
645 | while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb)) | |
646 | cpu_relax(); | |
dc7d5527 JW |
647 | } |
648 | ||
649 | kgdb_restore: | |
028e7b17 JW |
650 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
651 | int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); | |
652 | if (kgdb_info[sstep_cpu].task) | |
653 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; | |
654 | else | |
655 | kgdb_sstep_pid = 0; | |
656 | } | |
c1bb9a9c DD |
657 | if (arch_kgdb_ops.correct_hw_break) |
658 | arch_kgdb_ops.correct_hw_break(); | |
4da75b9c JW |
659 | if (trace_on) |
660 | tracing_on(); | |
dfee3a7b JW |
661 | |
662 | kgdb_info[cpu].exception_state &= | |
663 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); | |
664 | kgdb_info[cpu].enter_kgdb--; | |
4e857c58 | 665 | smp_mb__before_atomic(); |
dfee3a7b | 666 | atomic_dec(&masters_in_kgdb); |
dc7d5527 JW |
667 | /* Free kgdb_active */ |
668 | atomic_set(&kgdb_active, -1); | |
dfee3a7b | 669 | raw_spin_unlock(&dbg_master_lock); |
16cdc628 | 670 | dbg_touch_watchdogs(); |
dc7d5527 JW |
671 | local_irq_restore(flags); |
672 | ||
dcc78711 | 673 | return kgdb_info[cpu].ret_state; |
dc7d5527 JW |
674 | } |
675 | ||
62fae312 JW |
676 | /* |
677 | * kgdb_handle_exception() - main entry point from a kernel exception | |
678 | * | |
679 | * Locking hierarchy: | |
680 | * interface locks, if any (begin_session) | |
681 | * kgdb lock (kgdb_active) | |
682 | */ | |
683 | int | |
684 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) | |
685 | { | |
686 | struct kgdb_state kgdb_var; | |
687 | struct kgdb_state *ks = &kgdb_var; | |
5a14fead AV |
688 | int ret = 0; |
689 | ||
690 | if (arch_kgdb_ops.enable_nmi) | |
691 | arch_kgdb_ops.enable_nmi(0); | |
62fae312 | 692 | |
8daaa5f8 | 693 | memset(ks, 0, sizeof(struct kgdb_state)); |
62fae312 JW |
694 | ks->cpu = raw_smp_processor_id(); |
695 | ks->ex_vector = evector; | |
696 | ks->signo = signo; | |
62fae312 | 697 | ks->err_code = ecode; |
62fae312 JW |
698 | ks->linux_regs = regs; |
699 | ||
700 | if (kgdb_reenter_check(ks)) | |
5a14fead | 701 | goto out; /* Ouch, double exception ! */ |
dfee3a7b | 702 | if (kgdb_info[ks->cpu].enter_kgdb != 0) |
5a14fead | 703 | goto out; |
dfee3a7b | 704 | |
5a14fead AV |
705 | ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
706 | out: | |
707 | if (arch_kgdb_ops.enable_nmi) | |
708 | arch_kgdb_ops.enable_nmi(1); | |
709 | return ret; | |
62fae312 JW |
710 | } |
711 | ||
f30fed10 JW |
712 | /* |
713 | * GDB places a breakpoint at this function to know dynamically | |
714 | * loaded objects. It's not defined static so that only one instance with this | |
715 | * name exists in the kernel. | |
716 | */ | |
717 | ||
718 | static int module_event(struct notifier_block *self, unsigned long val, | |
719 | void *data) | |
720 | { | |
721 | return 0; | |
722 | } | |
723 | ||
724 | static struct notifier_block dbg_module_load_nb = { | |
725 | .notifier_call = module_event, | |
726 | }; | |
727 | ||
dc7d5527 JW |
728 | int kgdb_nmicallback(int cpu, void *regs) |
729 | { | |
730 | #ifdef CONFIG_SMP | |
62fae312 JW |
731 | struct kgdb_state kgdb_var; |
732 | struct kgdb_state *ks = &kgdb_var; | |
733 | ||
734 | memset(ks, 0, sizeof(struct kgdb_state)); | |
735 | ks->cpu = cpu; | |
736 | ks->linux_regs = regs; | |
737 | ||
dfee3a7b JW |
738 | if (kgdb_info[ks->cpu].enter_kgdb == 0 && |
739 | raw_spin_is_locked(&dbg_master_lock)) { | |
740 | kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); | |
dc7d5527 JW |
741 | return 0; |
742 | } | |
743 | #endif | |
744 | return 1; | |
745 | } | |
746 | ||
fc8b1374 MT |
747 | int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, |
748 | atomic_t *send_ready) | |
8daaa5f8 MT |
749 | { |
750 | #ifdef CONFIG_SMP | |
751 | if (!kgdb_io_ready(0) || !send_ready) | |
752 | return 1; | |
753 | ||
754 | if (kgdb_info[cpu].enter_kgdb == 0) { | |
755 | struct kgdb_state kgdb_var; | |
756 | struct kgdb_state *ks = &kgdb_var; | |
757 | ||
758 | memset(ks, 0, sizeof(struct kgdb_state)); | |
759 | ks->cpu = cpu; | |
760 | ks->ex_vector = trapnr; | |
761 | ks->signo = SIGTRAP; | |
fc8b1374 | 762 | ks->err_code = err_code; |
8daaa5f8 MT |
763 | ks->linux_regs = regs; |
764 | ks->send_ready = send_ready; | |
765 | kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); | |
766 | return 0; | |
767 | } | |
768 | #endif | |
769 | return 1; | |
770 | } | |
771 | ||
aabdc3b8 JW |
772 | static void kgdb_console_write(struct console *co, const char *s, |
773 | unsigned count) | |
dc7d5527 JW |
774 | { |
775 | unsigned long flags; | |
776 | ||
777 | /* If we're debugging, or KGDB has not connected, don't try | |
778 | * and print. */ | |
dcc78711 | 779 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) |
dc7d5527 JW |
780 | return; |
781 | ||
782 | local_irq_save(flags); | |
53197fc4 | 783 | gdbstub_msg_write(s, count); |
dc7d5527 JW |
784 | local_irq_restore(flags); |
785 | } | |
786 | ||
787 | static struct console kgdbcons = { | |
788 | .name = "kgdb", | |
789 | .write = kgdb_console_write, | |
790 | .flags = CON_PRINTBUFFER | CON_ENABLED, | |
791 | .index = -1, | |
792 | }; | |
793 | ||
794 | #ifdef CONFIG_MAGIC_SYSRQ | |
1495cc9d | 795 | static void sysrq_handle_dbg(int key) |
dc7d5527 | 796 | { |
53197fc4 | 797 | if (!dbg_io_ops) { |
dc7d5527 JW |
798 | printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); |
799 | return; | |
800 | } | |
dcc78711 JW |
801 | if (!kgdb_connected) { |
802 | #ifdef CONFIG_KGDB_KDB | |
803 | if (!dbg_kdb_mode) | |
804 | printk(KERN_CRIT "KGDB or $3#33 for KDB\n"); | |
805 | #else | |
dc7d5527 | 806 | printk(KERN_CRIT "Entering KGDB\n"); |
dcc78711 JW |
807 | #endif |
808 | } | |
dc7d5527 JW |
809 | |
810 | kgdb_breakpoint(); | |
811 | } | |
812 | ||
53197fc4 JW |
813 | static struct sysrq_key_op sysrq_dbg_op = { |
814 | .handler = sysrq_handle_dbg, | |
f3456509 | 815 | .help_msg = "debug(g)", |
364b5b7b | 816 | .action_msg = "DEBUG", |
dc7d5527 JW |
817 | }; |
818 | #endif | |
819 | ||
4402c153 JW |
820 | static int kgdb_panic_event(struct notifier_block *self, |
821 | unsigned long val, | |
822 | void *data) | |
823 | { | |
824 | if (dbg_kdb_mode) | |
825 | kdb_printf("PANIC: %s\n", (char *)data); | |
826 | kgdb_breakpoint(); | |
827 | return NOTIFY_DONE; | |
828 | } | |
829 | ||
830 | static struct notifier_block kgdb_panic_event_nb = { | |
831 | .notifier_call = kgdb_panic_event, | |
832 | .priority = INT_MAX, | |
833 | }; | |
834 | ||
0b4b3827 JW |
835 | void __weak kgdb_arch_late(void) |
836 | { | |
837 | } | |
838 | ||
839 | void __init dbg_late_init(void) | |
840 | { | |
841 | dbg_is_early = false; | |
842 | if (kgdb_io_module_registered) | |
843 | kgdb_arch_late(); | |
844 | kdb_init(KDB_INIT_FULL); | |
845 | } | |
846 | ||
2366e047 JW |
847 | static int |
848 | dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x) | |
849 | { | |
bec4d62e JW |
850 | /* |
851 | * Take the following action on reboot notify depending on value: | |
852 | * 1 == Enter debugger | |
853 | * 0 == [the default] detatch debug client | |
854 | * -1 == Do nothing... and use this until the board resets | |
855 | */ | |
856 | switch (kgdbreboot) { | |
857 | case 1: | |
858 | kgdb_breakpoint(); | |
859 | case -1: | |
860 | goto done; | |
861 | } | |
2366e047 JW |
862 | if (!dbg_kdb_mode) |
863 | gdbstub_exit(code); | |
bec4d62e | 864 | done: |
2366e047 JW |
865 | return NOTIFY_DONE; |
866 | } | |
867 | ||
868 | static struct notifier_block dbg_reboot_notifier = { | |
869 | .notifier_call = dbg_notify_reboot, | |
870 | .next = NULL, | |
871 | .priority = INT_MAX, | |
872 | }; | |
873 | ||
dc7d5527 JW |
874 | static void kgdb_register_callbacks(void) |
875 | { | |
876 | if (!kgdb_io_module_registered) { | |
877 | kgdb_io_module_registered = 1; | |
878 | kgdb_arch_init(); | |
0b4b3827 JW |
879 | if (!dbg_is_early) |
880 | kgdb_arch_late(); | |
f30fed10 | 881 | register_module_notifier(&dbg_module_load_nb); |
2366e047 | 882 | register_reboot_notifier(&dbg_reboot_notifier); |
4402c153 JW |
883 | atomic_notifier_chain_register(&panic_notifier_list, |
884 | &kgdb_panic_event_nb); | |
dc7d5527 | 885 | #ifdef CONFIG_MAGIC_SYSRQ |
53197fc4 | 886 | register_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
887 | #endif |
888 | if (kgdb_use_con && !kgdb_con_registered) { | |
889 | register_console(&kgdbcons); | |
890 | kgdb_con_registered = 1; | |
891 | } | |
892 | } | |
893 | } | |
894 | ||
895 | static void kgdb_unregister_callbacks(void) | |
896 | { | |
897 | /* | |
898 | * When this routine is called KGDB should unregister from the | |
899 | * panic handler and clean up, making sure it is not handling any | |
900 | * break exceptions at the time. | |
901 | */ | |
902 | if (kgdb_io_module_registered) { | |
903 | kgdb_io_module_registered = 0; | |
2366e047 | 904 | unregister_reboot_notifier(&dbg_reboot_notifier); |
f30fed10 | 905 | unregister_module_notifier(&dbg_module_load_nb); |
4402c153 JW |
906 | atomic_notifier_chain_unregister(&panic_notifier_list, |
907 | &kgdb_panic_event_nb); | |
dc7d5527 JW |
908 | kgdb_arch_exit(); |
909 | #ifdef CONFIG_MAGIC_SYSRQ | |
53197fc4 | 910 | unregister_sysrq_key('g', &sysrq_dbg_op); |
dc7d5527 JW |
911 | #endif |
912 | if (kgdb_con_registered) { | |
913 | unregister_console(&kgdbcons); | |
914 | kgdb_con_registered = 0; | |
915 | } | |
916 | } | |
917 | } | |
918 | ||
1cee5e35 JW |
919 | /* |
920 | * There are times a tasklet needs to be used vs a compiled in | |
921 | * break point so as to cause an exception outside a kgdb I/O module, | |
922 | * such as is the case with kgdboe, where calling a breakpoint in the | |
923 | * I/O driver itself would be fatal. | |
924 | */ | |
925 | static void kgdb_tasklet_bpt(unsigned long ing) | |
926 | { | |
927 | kgdb_breakpoint(); | |
928 | atomic_set(&kgdb_break_tasklet_var, 0); | |
929 | } | |
930 | ||
931 | static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0); | |
932 | ||
933 | void kgdb_schedule_breakpoint(void) | |
934 | { | |
935 | if (atomic_read(&kgdb_break_tasklet_var) || | |
936 | atomic_read(&kgdb_active) != -1 || | |
937 | atomic_read(&kgdb_setting_breakpoint)) | |
938 | return; | |
939 | atomic_inc(&kgdb_break_tasklet_var); | |
940 | tasklet_schedule(&kgdb_tasklet_breakpoint); | |
941 | } | |
942 | EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint); | |
943 | ||
dc7d5527 JW |
944 | static void kgdb_initial_breakpoint(void) |
945 | { | |
946 | kgdb_break_asap = 0; | |
947 | ||
948 | printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n"); | |
949 | kgdb_breakpoint(); | |
950 | } | |
951 | ||
952 | /** | |
737a460f | 953 | * kgdb_register_io_module - register KGDB IO module |
53197fc4 | 954 | * @new_dbg_io_ops: the io ops vector |
dc7d5527 JW |
955 | * |
956 | * Register it with the KGDB core. | |
957 | */ | |
53197fc4 | 958 | int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
dc7d5527 JW |
959 | { |
960 | int err; | |
961 | ||
962 | spin_lock(&kgdb_registration_lock); | |
963 | ||
53197fc4 | 964 | if (dbg_io_ops) { |
dc7d5527 JW |
965 | spin_unlock(&kgdb_registration_lock); |
966 | ||
967 | printk(KERN_ERR "kgdb: Another I/O driver is already " | |
968 | "registered with KGDB.\n"); | |
969 | return -EBUSY; | |
970 | } | |
971 | ||
53197fc4 JW |
972 | if (new_dbg_io_ops->init) { |
973 | err = new_dbg_io_ops->init(); | |
dc7d5527 JW |
974 | if (err) { |
975 | spin_unlock(&kgdb_registration_lock); | |
976 | return err; | |
977 | } | |
978 | } | |
979 | ||
53197fc4 | 980 | dbg_io_ops = new_dbg_io_ops; |
dc7d5527 JW |
981 | |
982 | spin_unlock(&kgdb_registration_lock); | |
983 | ||
984 | printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", | |
53197fc4 | 985 | new_dbg_io_ops->name); |
dc7d5527 JW |
986 | |
987 | /* Arm KGDB now. */ | |
988 | kgdb_register_callbacks(); | |
989 | ||
990 | if (kgdb_break_asap) | |
991 | kgdb_initial_breakpoint(); | |
992 | ||
993 | return 0; | |
994 | } | |
995 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); | |
996 | ||
997 | /** | |
998 | * kkgdb_unregister_io_module - unregister KGDB IO module | |
53197fc4 | 999 | * @old_dbg_io_ops: the io ops vector |
dc7d5527 JW |
1000 | * |
1001 | * Unregister it with the KGDB core. | |
1002 | */ | |
53197fc4 | 1003 | void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
dc7d5527 JW |
1004 | { |
1005 | BUG_ON(kgdb_connected); | |
1006 | ||
1007 | /* | |
1008 | * KGDB is no longer able to communicate out, so | |
1009 | * unregister our callbacks and reset state. | |
1010 | */ | |
1011 | kgdb_unregister_callbacks(); | |
1012 | ||
1013 | spin_lock(&kgdb_registration_lock); | |
1014 | ||
53197fc4 JW |
1015 | WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); |
1016 | dbg_io_ops = NULL; | |
dc7d5527 JW |
1017 | |
1018 | spin_unlock(&kgdb_registration_lock); | |
1019 | ||
1020 | printk(KERN_INFO | |
1021 | "kgdb: Unregistered I/O driver %s, debugger disabled.\n", | |
53197fc4 | 1022 | old_dbg_io_ops->name); |
dc7d5527 JW |
1023 | } |
1024 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); | |
1025 | ||
dcc78711 JW |
1026 | int dbg_io_get_char(void) |
1027 | { | |
1028 | int ret = dbg_io_ops->read_char(); | |
f5316b4a JW |
1029 | if (ret == NO_POLL_CHAR) |
1030 | return -1; | |
dcc78711 JW |
1031 | if (!dbg_kdb_mode) |
1032 | return ret; | |
1033 | if (ret == 127) | |
1034 | return 8; | |
1035 | return ret; | |
1036 | } | |
1037 | ||
dc7d5527 JW |
1038 | /** |
1039 | * kgdb_breakpoint - generate breakpoint exception | |
1040 | * | |
1041 | * This function will generate a breakpoint exception. It is used at the | |
1042 | * beginning of a program to sync up with a debugger and can be used | |
1043 | * otherwise as a quick means to stop program execution and "break" into | |
1044 | * the debugger. | |
1045 | */ | |
d498d4b4 | 1046 | noinline void kgdb_breakpoint(void) |
dc7d5527 | 1047 | { |
ae6bf53e | 1048 | atomic_inc(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1049 | wmb(); /* Sync point before breakpoint */ |
1050 | arch_kgdb_breakpoint(); | |
1051 | wmb(); /* Sync point after breakpoint */ | |
ae6bf53e | 1052 | atomic_dec(&kgdb_setting_breakpoint); |
dc7d5527 JW |
1053 | } |
1054 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); | |
1055 | ||
1056 | static int __init opt_kgdb_wait(char *str) | |
1057 | { | |
1058 | kgdb_break_asap = 1; | |
1059 | ||
dcc78711 | 1060 | kdb_init(KDB_INIT_EARLY); |
dc7d5527 JW |
1061 | if (kgdb_io_module_registered) |
1062 | kgdb_initial_breakpoint(); | |
1063 | ||
1064 | return 0; | |
1065 | } | |
1066 | ||
1067 | early_param("kgdbwait", opt_kgdb_wait); |