4 * Maintainer: Jason Wessel <jason.wessel@windriver.com>
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>
9 * Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
10 * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
11 * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
12 * Copyright (C) 2005-2009 Wind River Systems, Inc.
13 * Copyright (C) 2007 MontaVista Software, Inc.
14 * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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.
23 * Original KGDB stub: David Grothe <dave@gcom.com>,
24 * Tigran Aivazian <tigran@sco.com>
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.
30 #include <linux/pid_namespace.h>
31 #include <linux/clocksource.h>
32 #include <linux/interrupt.h>
33 #include <linux/spinlock.h>
34 #include <linux/console.h>
35 #include <linux/threads.h>
36 #include <linux/uaccess.h>
37 #include <linux/kernel.h>
38 #include <linux/module.h>
39 #include <linux/ptrace.h>
40 #include <linux/string.h>
41 #include <linux/delay.h>
42 #include <linux/sched.h>
43 #include <linux/sysrq.h>
44 #include <linux/init.h>
45 #include <linux/kgdb.h>
46 #include <linux/kdb.h>
47 #include <linux/pid.h>
48 #include <linux/smp.h>
51 #include <asm/cacheflush.h>
52 #include <asm/byteorder.h>
53 #include <asm/atomic.h>
54 #include <asm/system.h>
56 #include "debug_core.h"
58 static int kgdb_break_asap;
60 struct debuggerinfo_struct kgdb_info[NR_CPUS];
63 * kgdb_connected - Is a host GDB connected to us?
66 EXPORT_SYMBOL_GPL(kgdb_connected);
68 /* All the KGDB handlers are installed */
69 int kgdb_io_module_registered;
71 /* Guard for recursive entry */
72 static int exception_level;
74 struct kgdb_io *dbg_io_ops;
75 static DEFINE_SPINLOCK(kgdb_registration_lock);
77 /* kgdb console driver is loaded */
78 static int kgdb_con_registered;
79 /* determine if kgdb console output should be used */
80 static int kgdb_use_con;
81 /* Next cpu to become the master debug core */
84 /* Use kdb or gdbserver mode */
87 static int __init opt_kgdb_con(char *str)
93 early_param("kgdbcon", opt_kgdb_con);
95 module_param(kgdb_use_con, int, 0644);
98 * Holds information about breakpoints in a kernel. These breakpoints are
99 * added and removed by gdb.
101 static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
102 [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
106 * The CPU# of the active CPU, or -1 if none:
108 atomic_t kgdb_active = ATOMIC_INIT(-1);
109 EXPORT_SYMBOL_GPL(kgdb_active);
112 * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
113 * bootup code (which might not have percpu set up yet):
115 static atomic_t passive_cpu_wait[NR_CPUS];
116 static atomic_t cpu_in_kgdb[NR_CPUS];
117 static atomic_t kgdb_break_tasklet_var;
118 atomic_t kgdb_setting_breakpoint;
120 struct task_struct *kgdb_usethread;
121 struct task_struct *kgdb_contthread;
123 int kgdb_single_step;
124 static pid_t kgdb_sstep_pid;
126 /* to keep track of the CPU which is doing the single stepping*/
127 atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
130 * If you are debugging a problem where roundup (the collection of
131 * all other CPUs) is a problem [this should be extremely rare],
132 * then use the nokgdbroundup option to avoid roundup. In that case
133 * the other CPUs might interfere with your debugging context, so
134 * use this with care:
136 static int kgdb_do_roundup = 1;
138 static int __init opt_nokgdbroundup(char *str)
145 early_param("nokgdbroundup", opt_nokgdbroundup);
148 * Finally, some KGDB code :-)
152 * Weak aliases for breakpoint management,
153 * can be overriden by architectures when needed:
155 int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
159 err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
163 return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
167 int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
169 return probe_kernel_write((char *)addr,
170 (char *)bundle, BREAK_INSTR_SIZE);
173 int __weak kgdb_validate_break_address(unsigned long addr)
175 char tmp_variable[BREAK_INSTR_SIZE];
177 /* Validate setting the breakpoint and then removing it. In the
178 * remove fails, the kernel needs to emit a bad message because we
179 * are deep trouble not being able to put things back the way we
182 err = kgdb_arch_set_breakpoint(addr, tmp_variable);
185 err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
187 printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
188 "memory destroyed at: %lx", addr);
192 unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
194 return instruction_pointer(regs);
197 int __weak kgdb_arch_init(void)
202 int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
208 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
209 * @regs: Current &struct pt_regs.
211 * This function will be called if the particular architecture must
212 * disable hardware debugging while it is processing gdb packets or
213 * handling exception.
215 void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
220 * Some architectures need cache flushes when we set/clear a
223 static void kgdb_flush_swbreak_addr(unsigned long addr)
225 if (!CACHE_FLUSH_IS_SAFE)
228 if (current->mm && current->mm->mmap_cache) {
229 flush_cache_range(current->mm->mmap_cache,
230 addr, addr + BREAK_INSTR_SIZE);
232 /* Force flush instruction cache if it was outside the mm */
233 flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
237 * SW breakpoint management:
239 int dbg_activate_sw_breakpoints(void)
246 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
247 if (kgdb_break[i].state != BP_SET)
250 addr = kgdb_break[i].bpt_addr;
251 error = kgdb_arch_set_breakpoint(addr,
252 kgdb_break[i].saved_instr);
255 printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
259 kgdb_flush_swbreak_addr(addr);
260 kgdb_break[i].state = BP_ACTIVE;
265 int dbg_set_sw_break(unsigned long addr)
267 int err = kgdb_validate_break_address(addr);
274 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
275 if ((kgdb_break[i].state == BP_SET) &&
276 (kgdb_break[i].bpt_addr == addr))
279 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
280 if (kgdb_break[i].state == BP_REMOVED &&
281 kgdb_break[i].bpt_addr == addr) {
288 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
289 if (kgdb_break[i].state == BP_UNDEFINED) {
299 kgdb_break[breakno].state = BP_SET;
300 kgdb_break[breakno].type = BP_BREAKPOINT;
301 kgdb_break[breakno].bpt_addr = addr;
306 int dbg_deactivate_sw_breakpoints(void)
313 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
314 if (kgdb_break[i].state != BP_ACTIVE)
316 addr = kgdb_break[i].bpt_addr;
317 error = kgdb_arch_remove_breakpoint(addr,
318 kgdb_break[i].saved_instr);
320 printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
324 kgdb_flush_swbreak_addr(addr);
325 kgdb_break[i].state = BP_SET;
330 int dbg_remove_sw_break(unsigned long addr)
334 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
335 if ((kgdb_break[i].state == BP_SET) &&
336 (kgdb_break[i].bpt_addr == addr)) {
337 kgdb_break[i].state = BP_REMOVED;
344 int kgdb_isremovedbreak(unsigned long addr)
348 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
349 if ((kgdb_break[i].state == BP_REMOVED) &&
350 (kgdb_break[i].bpt_addr == addr))
356 int dbg_remove_all_break(void)
362 /* Clear memory breakpoints. */
363 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
364 if (kgdb_break[i].state != BP_ACTIVE)
366 addr = kgdb_break[i].bpt_addr;
367 error = kgdb_arch_remove_breakpoint(addr,
368 kgdb_break[i].saved_instr);
370 printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
373 kgdb_break[i].state = BP_UNDEFINED;
376 /* Clear hardware breakpoints. */
377 if (arch_kgdb_ops.remove_all_hw_break)
378 arch_kgdb_ops.remove_all_hw_break();
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.
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.
392 static int kgdb_io_ready(int print_wait)
398 if (atomic_read(&kgdb_setting_breakpoint))
401 #ifdef CONFIG_KGDB_KDB
403 printk(KERN_CRIT "KGDB: waiting... or $3#33 for KDB\n");
405 printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
411 static int kgdb_reenter_check(struct kgdb_state *ks)
415 if (atomic_read(&kgdb_active) != raw_smp_processor_id())
418 /* Panic on recursive debugger calls: */
420 addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
421 dbg_deactivate_sw_breakpoints();
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.
429 if (dbg_remove_sw_break(addr) == 0) {
431 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
432 dbg_activate_sw_breakpoints();
433 printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n",
439 dbg_remove_all_break();
440 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
442 if (exception_level > 1) {
444 panic("Recursive entry to debugger");
447 printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
449 panic("Recursive entry to debugger");
454 static void dbg_cpu_switch(int cpu, int next_cpu)
456 /* Mark the cpu we are switching away from as a slave when it
457 * holds the kgdb_active token. This must be done so that the
458 * that all the cpus wait in for the debug core will not enter
459 * again as the master. */
460 if (cpu == atomic_read(&kgdb_active)) {
461 kgdb_info[cpu].exception_state |= DCPU_IS_SLAVE;
462 kgdb_info[cpu].exception_state &= ~DCPU_WANT_MASTER;
464 kgdb_info[next_cpu].exception_state |= DCPU_NEXT_MASTER;
467 static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs)
470 int sstep_tries = 100;
476 * Interrupts will be restored by the 'trap return' code, except when
479 local_irq_save(flags);
482 kgdb_info[cpu].debuggerinfo = regs;
483 kgdb_info[cpu].task = current;
484 kgdb_info[cpu].ret_state = 0;
485 kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT;
487 * Make sure the above info reaches the primary CPU before
488 * our cpu_in_kgdb[] flag setting does:
490 atomic_inc(&cpu_in_kgdb[cpu]);
493 * CPU will loop if it is a slave or request to become a kgdb
494 * master cpu and acquire the kgdb_active lock:
498 if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) {
499 kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER;
500 goto cpu_master_loop;
501 } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) {
502 if (atomic_cmpxchg(&kgdb_active, -1, cpu) == cpu)
504 } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
505 if (!atomic_read(&passive_cpu_wait[cpu]))
509 /* Return to normal operation by executing any
510 * hw breakpoint fixup.
512 if (arch_kgdb_ops.correct_hw_break)
513 arch_kgdb_ops.correct_hw_break();
516 atomic_dec(&cpu_in_kgdb[cpu]);
517 touch_softlockup_watchdog_sync();
518 clocksource_touch_watchdog();
519 local_irq_restore(flags);
526 * For single stepping, try to only enter on the processor
527 * that was single stepping. To gaurd against a deadlock, the
528 * kernel will only try for the value of sstep_tries before
529 * giving up and continuing on.
531 if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
532 (kgdb_info[cpu].task &&
533 kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
534 atomic_set(&kgdb_active, -1);
535 touch_softlockup_watchdog_sync();
536 clocksource_touch_watchdog();
537 local_irq_restore(flags);
542 if (!kgdb_io_ready(1)) {
543 kgdb_info[cpu].ret_state = 1;
544 goto kgdb_restore; /* No I/O connection, resume the system */
548 * Don't enter if we have hit a removed breakpoint.
550 if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
553 /* Call the I/O driver's pre_exception routine */
554 if (dbg_io_ops->pre_exception)
555 dbg_io_ops->pre_exception();
557 kgdb_disable_hw_debug(ks->linux_regs);
560 * Get the passive CPU lock which will hold all the non-primary
561 * CPU in a spin state while the debugger is active
563 if (!kgdb_single_step) {
564 for (i = 0; i < NR_CPUS; i++)
565 atomic_inc(&passive_cpu_wait[i]);
569 /* Signal the other CPUs to enter kgdb_wait() */
570 if ((!kgdb_single_step) && kgdb_do_roundup)
571 kgdb_roundup_cpus(flags);
575 * Wait for the other CPUs to be notified and be waiting for us:
577 for_each_online_cpu(i) {
578 while (kgdb_do_roundup && !atomic_read(&cpu_in_kgdb[i]))
583 * At this point the primary processor is completely
584 * in the debugger and all secondary CPUs are quiescent
586 dbg_deactivate_sw_breakpoints();
587 kgdb_single_step = 0;
588 kgdb_contthread = current;
590 trace_on = tracing_is_on();
598 error = kdb_stub(ks);
600 error = gdb_serial_stub(ks);
603 if (error == DBG_PASS_EVENT) {
604 dbg_kdb_mode = !dbg_kdb_mode;
606 } else if (error == DBG_SWITCH_CPU_EVENT) {
607 dbg_cpu_switch(cpu, dbg_switch_cpu);
610 kgdb_info[cpu].ret_state = error;
615 /* Call the I/O driver's post_exception routine */
616 if (dbg_io_ops->post_exception)
617 dbg_io_ops->post_exception();
619 atomic_dec(&cpu_in_kgdb[ks->cpu]);
621 if (!kgdb_single_step) {
622 for (i = NR_CPUS-1; i >= 0; i--)
623 atomic_dec(&passive_cpu_wait[i]);
625 * Wait till all the CPUs have quit from the debugger,
626 * but allow a CPU that hit an exception and is
627 * waiting to become the master to remain in the debug
630 for_each_online_cpu(i) {
631 while (kgdb_do_roundup &&
632 atomic_read(&cpu_in_kgdb[i]) &&
633 !(kgdb_info[i].exception_state &
640 if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
641 int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step);
642 if (kgdb_info[sstep_cpu].task)
643 kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid;
649 /* Free kgdb_active */
650 atomic_set(&kgdb_active, -1);
651 touch_softlockup_watchdog_sync();
652 clocksource_touch_watchdog();
653 local_irq_restore(flags);
655 return kgdb_info[cpu].ret_state;
659 * kgdb_handle_exception() - main entry point from a kernel exception
662 * interface locks, if any (begin_session)
663 * kgdb lock (kgdb_active)
666 kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
668 struct kgdb_state kgdb_var;
669 struct kgdb_state *ks = &kgdb_var;
672 ks->cpu = raw_smp_processor_id();
673 ks->ex_vector = evector;
675 ks->err_code = ecode;
676 ks->kgdb_usethreadid = 0;
677 ks->linux_regs = regs;
679 if (kgdb_reenter_check(ks))
680 return 0; /* Ouch, double exception ! */
681 kgdb_info[ks->cpu].exception_state |= DCPU_WANT_MASTER;
682 ret = kgdb_cpu_enter(ks, regs);
683 kgdb_info[ks->cpu].exception_state &= ~(DCPU_WANT_MASTER |
688 int kgdb_nmicallback(int cpu, void *regs)
691 struct kgdb_state kgdb_var;
692 struct kgdb_state *ks = &kgdb_var;
694 memset(ks, 0, sizeof(struct kgdb_state));
696 ks->linux_regs = regs;
698 if (!atomic_read(&cpu_in_kgdb[cpu]) &&
699 atomic_read(&kgdb_active) != -1 &&
700 atomic_read(&kgdb_active) != cpu) {
701 kgdb_info[cpu].exception_state |= DCPU_IS_SLAVE;
702 kgdb_cpu_enter(ks, regs);
703 kgdb_info[cpu].exception_state &= ~DCPU_IS_SLAVE;
710 static void kgdb_console_write(struct console *co, const char *s,
715 /* If we're debugging, or KGDB has not connected, don't try
717 if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode)
720 local_irq_save(flags);
721 gdbstub_msg_write(s, count);
722 local_irq_restore(flags);
725 static struct console kgdbcons = {
727 .write = kgdb_console_write,
728 .flags = CON_PRINTBUFFER | CON_ENABLED,
732 #ifdef CONFIG_MAGIC_SYSRQ
733 static void sysrq_handle_dbg(int key, struct tty_struct *tty)
736 printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
739 if (!kgdb_connected) {
740 #ifdef CONFIG_KGDB_KDB
742 printk(KERN_CRIT "KGDB or $3#33 for KDB\n");
744 printk(KERN_CRIT "Entering KGDB\n");
751 static struct sysrq_key_op sysrq_dbg_op = {
752 .handler = sysrq_handle_dbg,
753 .help_msg = "debug(G)",
754 .action_msg = "DEBUG",
758 static void kgdb_register_callbacks(void)
760 if (!kgdb_io_module_registered) {
761 kgdb_io_module_registered = 1;
763 #ifdef CONFIG_MAGIC_SYSRQ
764 register_sysrq_key('g', &sysrq_dbg_op);
766 if (kgdb_use_con && !kgdb_con_registered) {
767 register_console(&kgdbcons);
768 kgdb_con_registered = 1;
773 static void kgdb_unregister_callbacks(void)
776 * When this routine is called KGDB should unregister from the
777 * panic handler and clean up, making sure it is not handling any
778 * break exceptions at the time.
780 if (kgdb_io_module_registered) {
781 kgdb_io_module_registered = 0;
783 #ifdef CONFIG_MAGIC_SYSRQ
784 unregister_sysrq_key('g', &sysrq_dbg_op);
786 if (kgdb_con_registered) {
787 unregister_console(&kgdbcons);
788 kgdb_con_registered = 0;
794 * There are times a tasklet needs to be used vs a compiled in
795 * break point so as to cause an exception outside a kgdb I/O module,
796 * such as is the case with kgdboe, where calling a breakpoint in the
797 * I/O driver itself would be fatal.
799 static void kgdb_tasklet_bpt(unsigned long ing)
802 atomic_set(&kgdb_break_tasklet_var, 0);
805 static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0);
807 void kgdb_schedule_breakpoint(void)
809 if (atomic_read(&kgdb_break_tasklet_var) ||
810 atomic_read(&kgdb_active) != -1 ||
811 atomic_read(&kgdb_setting_breakpoint))
813 atomic_inc(&kgdb_break_tasklet_var);
814 tasklet_schedule(&kgdb_tasklet_breakpoint);
816 EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint);
818 static void kgdb_initial_breakpoint(void)
822 printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
827 * kgdb_register_io_module - register KGDB IO module
828 * @new_dbg_io_ops: the io ops vector
830 * Register it with the KGDB core.
832 int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
836 spin_lock(&kgdb_registration_lock);
839 spin_unlock(&kgdb_registration_lock);
841 printk(KERN_ERR "kgdb: Another I/O driver is already "
842 "registered with KGDB.\n");
846 if (new_dbg_io_ops->init) {
847 err = new_dbg_io_ops->init();
849 spin_unlock(&kgdb_registration_lock);
854 dbg_io_ops = new_dbg_io_ops;
856 spin_unlock(&kgdb_registration_lock);
858 printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
859 new_dbg_io_ops->name);
862 kgdb_register_callbacks();
865 kgdb_initial_breakpoint();
869 EXPORT_SYMBOL_GPL(kgdb_register_io_module);
872 * kkgdb_unregister_io_module - unregister KGDB IO module
873 * @old_dbg_io_ops: the io ops vector
875 * Unregister it with the KGDB core.
877 void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops)
879 BUG_ON(kgdb_connected);
882 * KGDB is no longer able to communicate out, so
883 * unregister our callbacks and reset state.
885 kgdb_unregister_callbacks();
887 spin_lock(&kgdb_registration_lock);
889 WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops);
892 spin_unlock(&kgdb_registration_lock);
895 "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
896 old_dbg_io_ops->name);
898 EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
900 int dbg_io_get_char(void)
902 int ret = dbg_io_ops->read_char();
903 if (ret == NO_POLL_CHAR)
913 * kgdb_breakpoint - generate breakpoint exception
915 * This function will generate a breakpoint exception. It is used at the
916 * beginning of a program to sync up with a debugger and can be used
917 * otherwise as a quick means to stop program execution and "break" into
920 void kgdb_breakpoint(void)
922 atomic_inc(&kgdb_setting_breakpoint);
923 wmb(); /* Sync point before breakpoint */
924 arch_kgdb_breakpoint();
925 wmb(); /* Sync point after breakpoint */
926 atomic_dec(&kgdb_setting_breakpoint);
928 EXPORT_SYMBOL_GPL(kgdb_breakpoint);
930 static int __init opt_kgdb_wait(char *str)
934 kdb_init(KDB_INIT_EARLY);
935 if (kgdb_io_module_registered)
936 kgdb_initial_breakpoint();
941 early_param("kgdbwait", opt_kgdb_wait);