USB: fix interface unregistration logic
[linux-2.6/mini2440.git] / kernel / kgdb.c
blobeaa21fc9ad1d54250142a6c806115267865d3be6
1 /*
2 * KGDB stub.
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) 2005-2008 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/reboot.h>
41 #include <linux/string.h>
42 #include <linux/delay.h>
43 #include <linux/sched.h>
44 #include <linux/sysrq.h>
45 #include <linux/init.h>
46 #include <linux/kgdb.h>
47 #include <linux/pid.h>
48 #include <linux/smp.h>
49 #include <linux/mm.h>
51 #include <asm/cacheflush.h>
52 #include <asm/byteorder.h>
53 #include <asm/atomic.h>
54 #include <asm/system.h>
55 #include <asm/unaligned.h>
57 static int kgdb_break_asap;
59 #define KGDB_MAX_THREAD_QUERY 17
60 struct kgdb_state {
61 int ex_vector;
62 int signo;
63 int err_code;
64 int cpu;
65 int pass_exception;
66 unsigned long thr_query;
67 unsigned long threadid;
68 long kgdb_usethreadid;
69 struct pt_regs *linux_regs;
72 static struct debuggerinfo_struct {
73 void *debuggerinfo;
74 struct task_struct *task;
75 } kgdb_info[NR_CPUS];
77 /**
78 * kgdb_connected - Is a host GDB connected to us?
80 int kgdb_connected;
81 EXPORT_SYMBOL_GPL(kgdb_connected);
83 /* All the KGDB handlers are installed */
84 static int kgdb_io_module_registered;
86 /* Guard for recursive entry */
87 static int exception_level;
89 static struct kgdb_io *kgdb_io_ops;
90 static DEFINE_SPINLOCK(kgdb_registration_lock);
92 /* kgdb console driver is loaded */
93 static int kgdb_con_registered;
94 /* determine if kgdb console output should be used */
95 static int kgdb_use_con;
97 static int __init opt_kgdb_con(char *str)
99 kgdb_use_con = 1;
100 return 0;
103 early_param("kgdbcon", opt_kgdb_con);
105 module_param(kgdb_use_con, int, 0644);
108 * Holds information about breakpoints in a kernel. These breakpoints are
109 * added and removed by gdb.
111 static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
112 [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
116 * The CPU# of the active CPU, or -1 if none:
118 atomic_t kgdb_active = ATOMIC_INIT(-1);
121 * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
122 * bootup code (which might not have percpu set up yet):
124 static atomic_t passive_cpu_wait[NR_CPUS];
125 static atomic_t cpu_in_kgdb[NR_CPUS];
126 atomic_t kgdb_setting_breakpoint;
128 struct task_struct *kgdb_usethread;
129 struct task_struct *kgdb_contthread;
131 int kgdb_single_step;
133 /* Our I/O buffers. */
134 static char remcom_in_buffer[BUFMAX];
135 static char remcom_out_buffer[BUFMAX];
137 /* Storage for the registers, in GDB format. */
138 static unsigned long gdb_regs[(NUMREGBYTES +
139 sizeof(unsigned long) - 1) /
140 sizeof(unsigned long)];
142 /* to keep track of the CPU which is doing the single stepping*/
143 atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
146 * If you are debugging a problem where roundup (the collection of
147 * all other CPUs) is a problem [this should be extremely rare],
148 * then use the nokgdbroundup option to avoid roundup. In that case
149 * the other CPUs might interfere with your debugging context, so
150 * use this with care:
152 static int kgdb_do_roundup = 1;
154 static int __init opt_nokgdbroundup(char *str)
156 kgdb_do_roundup = 0;
158 return 0;
161 early_param("nokgdbroundup", opt_nokgdbroundup);
164 * Finally, some KGDB code :-)
168 * Weak aliases for breakpoint management,
169 * can be overriden by architectures when needed:
171 int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
173 int err;
175 err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
176 if (err)
177 return err;
179 return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
180 BREAK_INSTR_SIZE);
183 int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
185 return probe_kernel_write((char *)addr,
186 (char *)bundle, BREAK_INSTR_SIZE);
189 int __weak kgdb_validate_break_address(unsigned long addr)
191 char tmp_variable[BREAK_INSTR_SIZE];
192 int err;
193 /* Validate setting the breakpoint and then removing it. In the
194 * remove fails, the kernel needs to emit a bad message because we
195 * are deep trouble not being able to put things back the way we
196 * found them.
198 err = kgdb_arch_set_breakpoint(addr, tmp_variable);
199 if (err)
200 return err;
201 err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
202 if (err)
203 printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
204 "memory destroyed at: %lx", addr);
205 return err;
208 unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
210 return instruction_pointer(regs);
213 int __weak kgdb_arch_init(void)
215 return 0;
218 int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
220 return 0;
223 void __weak
224 kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
226 return;
230 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
231 * @regs: Current &struct pt_regs.
233 * This function will be called if the particular architecture must
234 * disable hardware debugging while it is processing gdb packets or
235 * handling exception.
237 void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
242 * GDB remote protocol parser:
245 static int hex(char ch)
247 if ((ch >= 'a') && (ch <= 'f'))
248 return ch - 'a' + 10;
249 if ((ch >= '0') && (ch <= '9'))
250 return ch - '0';
251 if ((ch >= 'A') && (ch <= 'F'))
252 return ch - 'A' + 10;
253 return -1;
256 /* scan for the sequence $<data>#<checksum> */
257 static void get_packet(char *buffer)
259 unsigned char checksum;
260 unsigned char xmitcsum;
261 int count;
262 char ch;
264 do {
266 * Spin and wait around for the start character, ignore all
267 * other characters:
269 while ((ch = (kgdb_io_ops->read_char())) != '$')
270 /* nothing */;
272 kgdb_connected = 1;
273 checksum = 0;
274 xmitcsum = -1;
276 count = 0;
279 * now, read until a # or end of buffer is found:
281 while (count < (BUFMAX - 1)) {
282 ch = kgdb_io_ops->read_char();
283 if (ch == '#')
284 break;
285 checksum = checksum + ch;
286 buffer[count] = ch;
287 count = count + 1;
289 buffer[count] = 0;
291 if (ch == '#') {
292 xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
293 xmitcsum += hex(kgdb_io_ops->read_char());
295 if (checksum != xmitcsum)
296 /* failed checksum */
297 kgdb_io_ops->write_char('-');
298 else
299 /* successful transfer */
300 kgdb_io_ops->write_char('+');
301 if (kgdb_io_ops->flush)
302 kgdb_io_ops->flush();
304 } while (checksum != xmitcsum);
308 * Send the packet in buffer.
309 * Check for gdb connection if asked for.
311 static void put_packet(char *buffer)
313 unsigned char checksum;
314 int count;
315 char ch;
318 * $<packet info>#<checksum>.
320 while (1) {
321 kgdb_io_ops->write_char('$');
322 checksum = 0;
323 count = 0;
325 while ((ch = buffer[count])) {
326 kgdb_io_ops->write_char(ch);
327 checksum += ch;
328 count++;
331 kgdb_io_ops->write_char('#');
332 kgdb_io_ops->write_char(hex_asc_hi(checksum));
333 kgdb_io_ops->write_char(hex_asc_lo(checksum));
334 if (kgdb_io_ops->flush)
335 kgdb_io_ops->flush();
337 /* Now see what we get in reply. */
338 ch = kgdb_io_ops->read_char();
340 if (ch == 3)
341 ch = kgdb_io_ops->read_char();
343 /* If we get an ACK, we are done. */
344 if (ch == '+')
345 return;
348 * If we get the start of another packet, this means
349 * that GDB is attempting to reconnect. We will NAK
350 * the packet being sent, and stop trying to send this
351 * packet.
353 if (ch == '$') {
354 kgdb_io_ops->write_char('-');
355 if (kgdb_io_ops->flush)
356 kgdb_io_ops->flush();
357 return;
363 * Convert the memory pointed to by mem into hex, placing result in buf.
364 * Return a pointer to the last char put in buf (null). May return an error.
366 int kgdb_mem2hex(char *mem, char *buf, int count)
368 char *tmp;
369 int err;
372 * We use the upper half of buf as an intermediate buffer for the
373 * raw memory copy. Hex conversion will work against this one.
375 tmp = buf + count;
377 err = probe_kernel_read(tmp, mem, count);
378 if (!err) {
379 while (count > 0) {
380 buf = pack_hex_byte(buf, *tmp);
381 tmp++;
382 count--;
385 *buf = 0;
388 return err;
392 * Copy the binary array pointed to by buf into mem. Fix $, #, and
393 * 0x7d escaped with 0x7d. Return a pointer to the character after
394 * the last byte written.
396 static int kgdb_ebin2mem(char *buf, char *mem, int count)
398 int err = 0;
399 char c;
401 while (count-- > 0) {
402 c = *buf++;
403 if (c == 0x7d)
404 c = *buf++ ^ 0x20;
406 err = probe_kernel_write(mem, &c, 1);
407 if (err)
408 break;
410 mem++;
413 return err;
417 * Convert the hex array pointed to by buf into binary to be placed in mem.
418 * Return a pointer to the character AFTER the last byte written.
419 * May return an error.
421 int kgdb_hex2mem(char *buf, char *mem, int count)
423 char *tmp_raw;
424 char *tmp_hex;
427 * We use the upper half of buf as an intermediate buffer for the
428 * raw memory that is converted from hex.
430 tmp_raw = buf + count * 2;
432 tmp_hex = tmp_raw - 1;
433 while (tmp_hex >= buf) {
434 tmp_raw--;
435 *tmp_raw = hex(*tmp_hex--);
436 *tmp_raw |= hex(*tmp_hex--) << 4;
439 return probe_kernel_write(mem, tmp_raw, count);
443 * While we find nice hex chars, build a long_val.
444 * Return number of chars processed.
446 int kgdb_hex2long(char **ptr, unsigned long *long_val)
448 int hex_val;
449 int num = 0;
450 int negate = 0;
452 *long_val = 0;
454 if (**ptr == '-') {
455 negate = 1;
456 (*ptr)++;
458 while (**ptr) {
459 hex_val = hex(**ptr);
460 if (hex_val < 0)
461 break;
463 *long_val = (*long_val << 4) | hex_val;
464 num++;
465 (*ptr)++;
468 if (negate)
469 *long_val = -*long_val;
471 return num;
474 /* Write memory due to an 'M' or 'X' packet. */
475 static int write_mem_msg(int binary)
477 char *ptr = &remcom_in_buffer[1];
478 unsigned long addr;
479 unsigned long length;
480 int err;
482 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
483 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
484 if (binary)
485 err = kgdb_ebin2mem(ptr, (char *)addr, length);
486 else
487 err = kgdb_hex2mem(ptr, (char *)addr, length);
488 if (err)
489 return err;
490 if (CACHE_FLUSH_IS_SAFE)
491 flush_icache_range(addr, addr + length + 1);
492 return 0;
495 return -EINVAL;
498 static void error_packet(char *pkt, int error)
500 error = -error;
501 pkt[0] = 'E';
502 pkt[1] = hex_asc[(error / 10)];
503 pkt[2] = hex_asc[(error % 10)];
504 pkt[3] = '\0';
508 * Thread ID accessors. We represent a flat TID space to GDB, where
509 * the per CPU idle threads (which under Linux all have PID 0) are
510 * remapped to negative TIDs.
513 #define BUF_THREAD_ID_SIZE 16
515 static char *pack_threadid(char *pkt, unsigned char *id)
517 char *limit;
519 limit = pkt + BUF_THREAD_ID_SIZE;
520 while (pkt < limit)
521 pkt = pack_hex_byte(pkt, *id++);
523 return pkt;
526 static void int_to_threadref(unsigned char *id, int value)
528 unsigned char *scan;
529 int i = 4;
531 scan = (unsigned char *)id;
532 while (i--)
533 *scan++ = 0;
534 put_unaligned_be32(value, scan);
537 static struct task_struct *getthread(struct pt_regs *regs, int tid)
540 * Non-positive TIDs are remapped to the cpu shadow information
542 if (tid == 0 || tid == -1)
543 tid = -atomic_read(&kgdb_active) - 2;
544 if (tid < 0) {
545 if (kgdb_info[-tid - 2].task)
546 return kgdb_info[-tid - 2].task;
547 else
548 return idle_task(-tid - 2);
552 * find_task_by_pid_ns() does not take the tasklist lock anymore
553 * but is nicely RCU locked - hence is a pretty resilient
554 * thing to use:
556 return find_task_by_pid_ns(tid, &init_pid_ns);
560 * CPU debug state control:
563 #ifdef CONFIG_SMP
564 static void kgdb_wait(struct pt_regs *regs)
566 unsigned long flags;
567 int cpu;
569 local_irq_save(flags);
570 cpu = raw_smp_processor_id();
571 kgdb_info[cpu].debuggerinfo = regs;
572 kgdb_info[cpu].task = current;
574 * Make sure the above info reaches the primary CPU before
575 * our cpu_in_kgdb[] flag setting does:
577 smp_wmb();
578 atomic_set(&cpu_in_kgdb[cpu], 1);
580 /* Wait till primary CPU is done with debugging */
581 while (atomic_read(&passive_cpu_wait[cpu]))
582 cpu_relax();
584 kgdb_info[cpu].debuggerinfo = NULL;
585 kgdb_info[cpu].task = NULL;
587 /* fix up hardware debug registers on local cpu */
588 if (arch_kgdb_ops.correct_hw_break)
589 arch_kgdb_ops.correct_hw_break();
591 /* Signal the primary CPU that we are done: */
592 atomic_set(&cpu_in_kgdb[cpu], 0);
593 clocksource_touch_watchdog();
594 local_irq_restore(flags);
596 #endif
599 * Some architectures need cache flushes when we set/clear a
600 * breakpoint:
602 static void kgdb_flush_swbreak_addr(unsigned long addr)
604 if (!CACHE_FLUSH_IS_SAFE)
605 return;
607 if (current->mm && current->mm->mmap_cache) {
608 flush_cache_range(current->mm->mmap_cache,
609 addr, addr + BREAK_INSTR_SIZE);
611 /* Force flush instruction cache if it was outside the mm */
612 flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
616 * SW breakpoint management:
618 static int kgdb_activate_sw_breakpoints(void)
620 unsigned long addr;
621 int error = 0;
622 int i;
624 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
625 if (kgdb_break[i].state != BP_SET)
626 continue;
628 addr = kgdb_break[i].bpt_addr;
629 error = kgdb_arch_set_breakpoint(addr,
630 kgdb_break[i].saved_instr);
631 if (error)
632 return error;
634 kgdb_flush_swbreak_addr(addr);
635 kgdb_break[i].state = BP_ACTIVE;
637 return 0;
640 static int kgdb_set_sw_break(unsigned long addr)
642 int err = kgdb_validate_break_address(addr);
643 int breakno = -1;
644 int i;
646 if (err)
647 return err;
649 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
650 if ((kgdb_break[i].state == BP_SET) &&
651 (kgdb_break[i].bpt_addr == addr))
652 return -EEXIST;
654 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
655 if (kgdb_break[i].state == BP_REMOVED &&
656 kgdb_break[i].bpt_addr == addr) {
657 breakno = i;
658 break;
662 if (breakno == -1) {
663 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
664 if (kgdb_break[i].state == BP_UNDEFINED) {
665 breakno = i;
666 break;
671 if (breakno == -1)
672 return -E2BIG;
674 kgdb_break[breakno].state = BP_SET;
675 kgdb_break[breakno].type = BP_BREAKPOINT;
676 kgdb_break[breakno].bpt_addr = addr;
678 return 0;
681 static int kgdb_deactivate_sw_breakpoints(void)
683 unsigned long addr;
684 int error = 0;
685 int i;
687 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
688 if (kgdb_break[i].state != BP_ACTIVE)
689 continue;
690 addr = kgdb_break[i].bpt_addr;
691 error = kgdb_arch_remove_breakpoint(addr,
692 kgdb_break[i].saved_instr);
693 if (error)
694 return error;
696 kgdb_flush_swbreak_addr(addr);
697 kgdb_break[i].state = BP_SET;
699 return 0;
702 static int kgdb_remove_sw_break(unsigned long addr)
704 int i;
706 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
707 if ((kgdb_break[i].state == BP_SET) &&
708 (kgdb_break[i].bpt_addr == addr)) {
709 kgdb_break[i].state = BP_REMOVED;
710 return 0;
713 return -ENOENT;
716 int kgdb_isremovedbreak(unsigned long addr)
718 int i;
720 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
721 if ((kgdb_break[i].state == BP_REMOVED) &&
722 (kgdb_break[i].bpt_addr == addr))
723 return 1;
725 return 0;
728 static int remove_all_break(void)
730 unsigned long addr;
731 int error;
732 int i;
734 /* Clear memory breakpoints. */
735 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
736 if (kgdb_break[i].state != BP_ACTIVE)
737 goto setundefined;
738 addr = kgdb_break[i].bpt_addr;
739 error = kgdb_arch_remove_breakpoint(addr,
740 kgdb_break[i].saved_instr);
741 if (error)
742 printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
743 addr);
744 setundefined:
745 kgdb_break[i].state = BP_UNDEFINED;
748 /* Clear hardware breakpoints. */
749 if (arch_kgdb_ops.remove_all_hw_break)
750 arch_kgdb_ops.remove_all_hw_break();
752 return 0;
756 * Remap normal tasks to their real PID,
757 * CPU shadow threads are mapped to -CPU - 2
759 static inline int shadow_pid(int realpid)
761 if (realpid)
762 return realpid;
764 return -raw_smp_processor_id() - 2;
767 static char gdbmsgbuf[BUFMAX + 1];
769 static void kgdb_msg_write(const char *s, int len)
771 char *bufptr;
772 int wcount;
773 int i;
775 /* 'O'utput */
776 gdbmsgbuf[0] = 'O';
778 /* Fill and send buffers... */
779 while (len > 0) {
780 bufptr = gdbmsgbuf + 1;
782 /* Calculate how many this time */
783 if ((len << 1) > (BUFMAX - 2))
784 wcount = (BUFMAX - 2) >> 1;
785 else
786 wcount = len;
788 /* Pack in hex chars */
789 for (i = 0; i < wcount; i++)
790 bufptr = pack_hex_byte(bufptr, s[i]);
791 *bufptr = '\0';
793 /* Move up */
794 s += wcount;
795 len -= wcount;
797 /* Write packet */
798 put_packet(gdbmsgbuf);
803 * Return true if there is a valid kgdb I/O module. Also if no
804 * debugger is attached a message can be printed to the console about
805 * waiting for the debugger to attach.
807 * The print_wait argument is only to be true when called from inside
808 * the core kgdb_handle_exception, because it will wait for the
809 * debugger to attach.
811 static int kgdb_io_ready(int print_wait)
813 if (!kgdb_io_ops)
814 return 0;
815 if (kgdb_connected)
816 return 1;
817 if (atomic_read(&kgdb_setting_breakpoint))
818 return 1;
819 if (print_wait)
820 printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
821 return 1;
825 * All the functions that start with gdb_cmd are the various
826 * operations to implement the handlers for the gdbserial protocol
827 * where KGDB is communicating with an external debugger
830 /* Handle the '?' status packets */
831 static void gdb_cmd_status(struct kgdb_state *ks)
834 * We know that this packet is only sent
835 * during initial connect. So to be safe,
836 * we clear out our breakpoints now in case
837 * GDB is reconnecting.
839 remove_all_break();
841 remcom_out_buffer[0] = 'S';
842 pack_hex_byte(&remcom_out_buffer[1], ks->signo);
845 /* Handle the 'g' get registers request */
846 static void gdb_cmd_getregs(struct kgdb_state *ks)
848 struct task_struct *thread;
849 void *local_debuggerinfo;
850 int i;
852 thread = kgdb_usethread;
853 if (!thread) {
854 thread = kgdb_info[ks->cpu].task;
855 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
856 } else {
857 local_debuggerinfo = NULL;
858 for_each_online_cpu(i) {
860 * Try to find the task on some other
861 * or possibly this node if we do not
862 * find the matching task then we try
863 * to approximate the results.
865 if (thread == kgdb_info[i].task)
866 local_debuggerinfo = kgdb_info[i].debuggerinfo;
871 * All threads that don't have debuggerinfo should be
872 * in __schedule() sleeping, since all other CPUs
873 * are in kgdb_wait, and thus have debuggerinfo.
875 if (local_debuggerinfo) {
876 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
877 } else {
879 * Pull stuff saved during switch_to; nothing
880 * else is accessible (or even particularly
881 * relevant).
883 * This should be enough for a stack trace.
885 sleeping_thread_to_gdb_regs(gdb_regs, thread);
887 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
890 /* Handle the 'G' set registers request */
891 static void gdb_cmd_setregs(struct kgdb_state *ks)
893 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
895 if (kgdb_usethread && kgdb_usethread != current) {
896 error_packet(remcom_out_buffer, -EINVAL);
897 } else {
898 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
899 strcpy(remcom_out_buffer, "OK");
903 /* Handle the 'm' memory read bytes */
904 static void gdb_cmd_memread(struct kgdb_state *ks)
906 char *ptr = &remcom_in_buffer[1];
907 unsigned long length;
908 unsigned long addr;
909 int err;
911 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
912 kgdb_hex2long(&ptr, &length) > 0) {
913 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
914 if (err)
915 error_packet(remcom_out_buffer, err);
916 } else {
917 error_packet(remcom_out_buffer, -EINVAL);
921 /* Handle the 'M' memory write bytes */
922 static void gdb_cmd_memwrite(struct kgdb_state *ks)
924 int err = write_mem_msg(0);
926 if (err)
927 error_packet(remcom_out_buffer, err);
928 else
929 strcpy(remcom_out_buffer, "OK");
932 /* Handle the 'X' memory binary write bytes */
933 static void gdb_cmd_binwrite(struct kgdb_state *ks)
935 int err = write_mem_msg(1);
937 if (err)
938 error_packet(remcom_out_buffer, err);
939 else
940 strcpy(remcom_out_buffer, "OK");
943 /* Handle the 'D' or 'k', detach or kill packets */
944 static void gdb_cmd_detachkill(struct kgdb_state *ks)
946 int error;
948 /* The detach case */
949 if (remcom_in_buffer[0] == 'D') {
950 error = remove_all_break();
951 if (error < 0) {
952 error_packet(remcom_out_buffer, error);
953 } else {
954 strcpy(remcom_out_buffer, "OK");
955 kgdb_connected = 0;
957 put_packet(remcom_out_buffer);
958 } else {
960 * Assume the kill case, with no exit code checking,
961 * trying to force detach the debugger:
963 remove_all_break();
964 kgdb_connected = 0;
968 /* Handle the 'R' reboot packets */
969 static int gdb_cmd_reboot(struct kgdb_state *ks)
971 /* For now, only honor R0 */
972 if (strcmp(remcom_in_buffer, "R0") == 0) {
973 printk(KERN_CRIT "Executing emergency reboot\n");
974 strcpy(remcom_out_buffer, "OK");
975 put_packet(remcom_out_buffer);
978 * Execution should not return from
979 * machine_emergency_restart()
981 machine_emergency_restart();
982 kgdb_connected = 0;
984 return 1;
986 return 0;
989 /* Handle the 'q' query packets */
990 static void gdb_cmd_query(struct kgdb_state *ks)
992 struct task_struct *g;
993 struct task_struct *p;
994 unsigned char thref[8];
995 char *ptr;
996 int i;
997 int cpu;
998 int finished = 0;
1000 switch (remcom_in_buffer[1]) {
1001 case 's':
1002 case 'f':
1003 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
1004 error_packet(remcom_out_buffer, -EINVAL);
1005 break;
1008 i = 0;
1009 remcom_out_buffer[0] = 'm';
1010 ptr = remcom_out_buffer + 1;
1011 if (remcom_in_buffer[1] == 'f') {
1012 /* Each cpu is a shadow thread */
1013 for_each_online_cpu(cpu) {
1014 ks->thr_query = 0;
1015 int_to_threadref(thref, -cpu - 2);
1016 pack_threadid(ptr, thref);
1017 ptr += BUF_THREAD_ID_SIZE;
1018 *(ptr++) = ',';
1019 i++;
1023 do_each_thread(g, p) {
1024 if (i >= ks->thr_query && !finished) {
1025 int_to_threadref(thref, p->pid);
1026 pack_threadid(ptr, thref);
1027 ptr += BUF_THREAD_ID_SIZE;
1028 *(ptr++) = ',';
1029 ks->thr_query++;
1030 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
1031 finished = 1;
1033 i++;
1034 } while_each_thread(g, p);
1036 *(--ptr) = '\0';
1037 break;
1039 case 'C':
1040 /* Current thread id */
1041 strcpy(remcom_out_buffer, "QC");
1042 ks->threadid = shadow_pid(current->pid);
1043 int_to_threadref(thref, ks->threadid);
1044 pack_threadid(remcom_out_buffer + 2, thref);
1045 break;
1046 case 'T':
1047 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
1048 error_packet(remcom_out_buffer, -EINVAL);
1049 break;
1051 ks->threadid = 0;
1052 ptr = remcom_in_buffer + 17;
1053 kgdb_hex2long(&ptr, &ks->threadid);
1054 if (!getthread(ks->linux_regs, ks->threadid)) {
1055 error_packet(remcom_out_buffer, -EINVAL);
1056 break;
1058 if ((int)ks->threadid > 0) {
1059 kgdb_mem2hex(getthread(ks->linux_regs,
1060 ks->threadid)->comm,
1061 remcom_out_buffer, 16);
1062 } else {
1063 static char tmpstr[23 + BUF_THREAD_ID_SIZE];
1065 sprintf(tmpstr, "shadowCPU%d",
1066 (int)(-ks->threadid - 2));
1067 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
1069 break;
1073 /* Handle the 'H' task query packets */
1074 static void gdb_cmd_task(struct kgdb_state *ks)
1076 struct task_struct *thread;
1077 char *ptr;
1079 switch (remcom_in_buffer[1]) {
1080 case 'g':
1081 ptr = &remcom_in_buffer[2];
1082 kgdb_hex2long(&ptr, &ks->threadid);
1083 thread = getthread(ks->linux_regs, ks->threadid);
1084 if (!thread && ks->threadid > 0) {
1085 error_packet(remcom_out_buffer, -EINVAL);
1086 break;
1088 kgdb_usethread = thread;
1089 ks->kgdb_usethreadid = ks->threadid;
1090 strcpy(remcom_out_buffer, "OK");
1091 break;
1092 case 'c':
1093 ptr = &remcom_in_buffer[2];
1094 kgdb_hex2long(&ptr, &ks->threadid);
1095 if (!ks->threadid) {
1096 kgdb_contthread = NULL;
1097 } else {
1098 thread = getthread(ks->linux_regs, ks->threadid);
1099 if (!thread && ks->threadid > 0) {
1100 error_packet(remcom_out_buffer, -EINVAL);
1101 break;
1103 kgdb_contthread = thread;
1105 strcpy(remcom_out_buffer, "OK");
1106 break;
1110 /* Handle the 'T' thread query packets */
1111 static void gdb_cmd_thread(struct kgdb_state *ks)
1113 char *ptr = &remcom_in_buffer[1];
1114 struct task_struct *thread;
1116 kgdb_hex2long(&ptr, &ks->threadid);
1117 thread = getthread(ks->linux_regs, ks->threadid);
1118 if (thread)
1119 strcpy(remcom_out_buffer, "OK");
1120 else
1121 error_packet(remcom_out_buffer, -EINVAL);
1124 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
1125 static void gdb_cmd_break(struct kgdb_state *ks)
1128 * Since GDB-5.3, it's been drafted that '0' is a software
1129 * breakpoint, '1' is a hardware breakpoint, so let's do that.
1131 char *bpt_type = &remcom_in_buffer[1];
1132 char *ptr = &remcom_in_buffer[2];
1133 unsigned long addr;
1134 unsigned long length;
1135 int error = 0;
1137 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
1138 /* Unsupported */
1139 if (*bpt_type > '4')
1140 return;
1141 } else {
1142 if (*bpt_type != '0' && *bpt_type != '1')
1143 /* Unsupported. */
1144 return;
1148 * Test if this is a hardware breakpoint, and
1149 * if we support it:
1151 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
1152 /* Unsupported. */
1153 return;
1155 if (*(ptr++) != ',') {
1156 error_packet(remcom_out_buffer, -EINVAL);
1157 return;
1159 if (!kgdb_hex2long(&ptr, &addr)) {
1160 error_packet(remcom_out_buffer, -EINVAL);
1161 return;
1163 if (*(ptr++) != ',' ||
1164 !kgdb_hex2long(&ptr, &length)) {
1165 error_packet(remcom_out_buffer, -EINVAL);
1166 return;
1169 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
1170 error = kgdb_set_sw_break(addr);
1171 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
1172 error = kgdb_remove_sw_break(addr);
1173 else if (remcom_in_buffer[0] == 'Z')
1174 error = arch_kgdb_ops.set_hw_breakpoint(addr,
1175 (int)length, *bpt_type - '0');
1176 else if (remcom_in_buffer[0] == 'z')
1177 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
1178 (int) length, *bpt_type - '0');
1180 if (error == 0)
1181 strcpy(remcom_out_buffer, "OK");
1182 else
1183 error_packet(remcom_out_buffer, error);
1186 /* Handle the 'C' signal / exception passing packets */
1187 static int gdb_cmd_exception_pass(struct kgdb_state *ks)
1189 /* C09 == pass exception
1190 * C15 == detach kgdb, pass exception
1192 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
1194 ks->pass_exception = 1;
1195 remcom_in_buffer[0] = 'c';
1197 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
1199 ks->pass_exception = 1;
1200 remcom_in_buffer[0] = 'D';
1201 remove_all_break();
1202 kgdb_connected = 0;
1203 return 1;
1205 } else {
1206 error_packet(remcom_out_buffer, -EINVAL);
1207 return 0;
1210 /* Indicate fall through */
1211 return -1;
1215 * This function performs all gdbserial command procesing
1217 static int gdb_serial_stub(struct kgdb_state *ks)
1219 int error = 0;
1220 int tmp;
1222 /* Clear the out buffer. */
1223 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1225 if (kgdb_connected) {
1226 unsigned char thref[8];
1227 char *ptr;
1229 /* Reply to host that an exception has occurred */
1230 ptr = remcom_out_buffer;
1231 *ptr++ = 'T';
1232 ptr = pack_hex_byte(ptr, ks->signo);
1233 ptr += strlen(strcpy(ptr, "thread:"));
1234 int_to_threadref(thref, shadow_pid(current->pid));
1235 ptr = pack_threadid(ptr, thref);
1236 *ptr++ = ';';
1237 put_packet(remcom_out_buffer);
1240 kgdb_usethread = kgdb_info[ks->cpu].task;
1241 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
1242 ks->pass_exception = 0;
1244 while (1) {
1245 error = 0;
1247 /* Clear the out buffer. */
1248 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1250 get_packet(remcom_in_buffer);
1252 switch (remcom_in_buffer[0]) {
1253 case '?': /* gdbserial status */
1254 gdb_cmd_status(ks);
1255 break;
1256 case 'g': /* return the value of the CPU registers */
1257 gdb_cmd_getregs(ks);
1258 break;
1259 case 'G': /* set the value of the CPU registers - return OK */
1260 gdb_cmd_setregs(ks);
1261 break;
1262 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
1263 gdb_cmd_memread(ks);
1264 break;
1265 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1266 gdb_cmd_memwrite(ks);
1267 break;
1268 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1269 gdb_cmd_binwrite(ks);
1270 break;
1271 /* kill or detach. KGDB should treat this like a
1272 * continue.
1274 case 'D': /* Debugger detach */
1275 case 'k': /* Debugger detach via kill */
1276 gdb_cmd_detachkill(ks);
1277 goto default_handle;
1278 case 'R': /* Reboot */
1279 if (gdb_cmd_reboot(ks))
1280 goto default_handle;
1281 break;
1282 case 'q': /* query command */
1283 gdb_cmd_query(ks);
1284 break;
1285 case 'H': /* task related */
1286 gdb_cmd_task(ks);
1287 break;
1288 case 'T': /* Query thread status */
1289 gdb_cmd_thread(ks);
1290 break;
1291 case 'z': /* Break point remove */
1292 case 'Z': /* Break point set */
1293 gdb_cmd_break(ks);
1294 break;
1295 case 'C': /* Exception passing */
1296 tmp = gdb_cmd_exception_pass(ks);
1297 if (tmp > 0)
1298 goto default_handle;
1299 if (tmp == 0)
1300 break;
1301 /* Fall through on tmp < 0 */
1302 case 'c': /* Continue packet */
1303 case 's': /* Single step packet */
1304 if (kgdb_contthread && kgdb_contthread != current) {
1305 /* Can't switch threads in kgdb */
1306 error_packet(remcom_out_buffer, -EINVAL);
1307 break;
1309 kgdb_activate_sw_breakpoints();
1310 /* Fall through to default processing */
1311 default:
1312 default_handle:
1313 error = kgdb_arch_handle_exception(ks->ex_vector,
1314 ks->signo,
1315 ks->err_code,
1316 remcom_in_buffer,
1317 remcom_out_buffer,
1318 ks->linux_regs);
1320 * Leave cmd processing on error, detach,
1321 * kill, continue, or single step.
1323 if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1324 remcom_in_buffer[0] == 'k') {
1325 error = 0;
1326 goto kgdb_exit;
1331 /* reply to the request */
1332 put_packet(remcom_out_buffer);
1335 kgdb_exit:
1336 if (ks->pass_exception)
1337 error = 1;
1338 return error;
1341 static int kgdb_reenter_check(struct kgdb_state *ks)
1343 unsigned long addr;
1345 if (atomic_read(&kgdb_active) != raw_smp_processor_id())
1346 return 0;
1348 /* Panic on recursive debugger calls: */
1349 exception_level++;
1350 addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
1351 kgdb_deactivate_sw_breakpoints();
1354 * If the break point removed ok at the place exception
1355 * occurred, try to recover and print a warning to the end
1356 * user because the user planted a breakpoint in a place that
1357 * KGDB needs in order to function.
1359 if (kgdb_remove_sw_break(addr) == 0) {
1360 exception_level = 0;
1361 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1362 kgdb_activate_sw_breakpoints();
1363 printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n",
1364 addr);
1365 WARN_ON_ONCE(1);
1367 return 1;
1369 remove_all_break();
1370 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1372 if (exception_level > 1) {
1373 dump_stack();
1374 panic("Recursive entry to debugger");
1377 printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
1378 dump_stack();
1379 panic("Recursive entry to debugger");
1381 return 1;
1385 * kgdb_handle_exception() - main entry point from a kernel exception
1387 * Locking hierarchy:
1388 * interface locks, if any (begin_session)
1389 * kgdb lock (kgdb_active)
1392 kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
1394 struct kgdb_state kgdb_var;
1395 struct kgdb_state *ks = &kgdb_var;
1396 unsigned long flags;
1397 int error = 0;
1398 int i, cpu;
1400 ks->cpu = raw_smp_processor_id();
1401 ks->ex_vector = evector;
1402 ks->signo = signo;
1403 ks->ex_vector = evector;
1404 ks->err_code = ecode;
1405 ks->kgdb_usethreadid = 0;
1406 ks->linux_regs = regs;
1408 if (kgdb_reenter_check(ks))
1409 return 0; /* Ouch, double exception ! */
1411 acquirelock:
1413 * Interrupts will be restored by the 'trap return' code, except when
1414 * single stepping.
1416 local_irq_save(flags);
1418 cpu = raw_smp_processor_id();
1421 * Acquire the kgdb_active lock:
1423 while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
1424 cpu_relax();
1427 * Do not start the debugger connection on this CPU if the last
1428 * instance of the exception handler wanted to come into the
1429 * debugger on a different CPU via a single step
1431 if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
1432 atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
1434 atomic_set(&kgdb_active, -1);
1435 clocksource_touch_watchdog();
1436 local_irq_restore(flags);
1438 goto acquirelock;
1441 if (!kgdb_io_ready(1)) {
1442 error = 1;
1443 goto kgdb_restore; /* No I/O connection, so resume the system */
1447 * Don't enter if we have hit a removed breakpoint.
1449 if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
1450 goto kgdb_restore;
1452 /* Call the I/O driver's pre_exception routine */
1453 if (kgdb_io_ops->pre_exception)
1454 kgdb_io_ops->pre_exception();
1456 kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
1457 kgdb_info[ks->cpu].task = current;
1459 kgdb_disable_hw_debug(ks->linux_regs);
1462 * Get the passive CPU lock which will hold all the non-primary
1463 * CPU in a spin state while the debugger is active
1465 if (!kgdb_single_step || !kgdb_contthread) {
1466 for (i = 0; i < NR_CPUS; i++)
1467 atomic_set(&passive_cpu_wait[i], 1);
1471 * spin_lock code is good enough as a barrier so we don't
1472 * need one here:
1474 atomic_set(&cpu_in_kgdb[ks->cpu], 1);
1476 #ifdef CONFIG_SMP
1477 /* Signal the other CPUs to enter kgdb_wait() */
1478 if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup)
1479 kgdb_roundup_cpus(flags);
1480 #endif
1483 * Wait for the other CPUs to be notified and be waiting for us:
1485 for_each_online_cpu(i) {
1486 while (!atomic_read(&cpu_in_kgdb[i]))
1487 cpu_relax();
1491 * At this point the primary processor is completely
1492 * in the debugger and all secondary CPUs are quiescent
1494 kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
1495 kgdb_deactivate_sw_breakpoints();
1496 kgdb_single_step = 0;
1497 kgdb_contthread = NULL;
1498 exception_level = 0;
1500 /* Talk to debugger with gdbserial protocol */
1501 error = gdb_serial_stub(ks);
1503 /* Call the I/O driver's post_exception routine */
1504 if (kgdb_io_ops->post_exception)
1505 kgdb_io_ops->post_exception();
1507 kgdb_info[ks->cpu].debuggerinfo = NULL;
1508 kgdb_info[ks->cpu].task = NULL;
1509 atomic_set(&cpu_in_kgdb[ks->cpu], 0);
1511 if (!kgdb_single_step || !kgdb_contthread) {
1512 for (i = NR_CPUS-1; i >= 0; i--)
1513 atomic_set(&passive_cpu_wait[i], 0);
1515 * Wait till all the CPUs have quit
1516 * from the debugger.
1518 for_each_online_cpu(i) {
1519 while (atomic_read(&cpu_in_kgdb[i]))
1520 cpu_relax();
1524 kgdb_restore:
1525 /* Free kgdb_active */
1526 atomic_set(&kgdb_active, -1);
1527 clocksource_touch_watchdog();
1528 local_irq_restore(flags);
1530 return error;
1533 int kgdb_nmicallback(int cpu, void *regs)
1535 #ifdef CONFIG_SMP
1536 if (!atomic_read(&cpu_in_kgdb[cpu]) &&
1537 atomic_read(&kgdb_active) != cpu &&
1538 atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) {
1539 kgdb_wait((struct pt_regs *)regs);
1540 return 0;
1542 #endif
1543 return 1;
1546 static void kgdb_console_write(struct console *co, const char *s,
1547 unsigned count)
1549 unsigned long flags;
1551 /* If we're debugging, or KGDB has not connected, don't try
1552 * and print. */
1553 if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
1554 return;
1556 local_irq_save(flags);
1557 kgdb_msg_write(s, count);
1558 local_irq_restore(flags);
1561 static struct console kgdbcons = {
1562 .name = "kgdb",
1563 .write = kgdb_console_write,
1564 .flags = CON_PRINTBUFFER | CON_ENABLED,
1565 .index = -1,
1568 #ifdef CONFIG_MAGIC_SYSRQ
1569 static void sysrq_handle_gdb(int key, struct tty_struct *tty)
1571 if (!kgdb_io_ops) {
1572 printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
1573 return;
1575 if (!kgdb_connected)
1576 printk(KERN_CRIT "Entering KGDB\n");
1578 kgdb_breakpoint();
1581 static struct sysrq_key_op sysrq_gdb_op = {
1582 .handler = sysrq_handle_gdb,
1583 .help_msg = "Gdb",
1584 .action_msg = "GDB",
1586 #endif
1588 static void kgdb_register_callbacks(void)
1590 if (!kgdb_io_module_registered) {
1591 kgdb_io_module_registered = 1;
1592 kgdb_arch_init();
1593 #ifdef CONFIG_MAGIC_SYSRQ
1594 register_sysrq_key('g', &sysrq_gdb_op);
1595 #endif
1596 if (kgdb_use_con && !kgdb_con_registered) {
1597 register_console(&kgdbcons);
1598 kgdb_con_registered = 1;
1603 static void kgdb_unregister_callbacks(void)
1606 * When this routine is called KGDB should unregister from the
1607 * panic handler and clean up, making sure it is not handling any
1608 * break exceptions at the time.
1610 if (kgdb_io_module_registered) {
1611 kgdb_io_module_registered = 0;
1612 kgdb_arch_exit();
1613 #ifdef CONFIG_MAGIC_SYSRQ
1614 unregister_sysrq_key('g', &sysrq_gdb_op);
1615 #endif
1616 if (kgdb_con_registered) {
1617 unregister_console(&kgdbcons);
1618 kgdb_con_registered = 0;
1623 static void kgdb_initial_breakpoint(void)
1625 kgdb_break_asap = 0;
1627 printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
1628 kgdb_breakpoint();
1632 * kgdb_register_io_module - register KGDB IO module
1633 * @new_kgdb_io_ops: the io ops vector
1635 * Register it with the KGDB core.
1637 int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
1639 int err;
1641 spin_lock(&kgdb_registration_lock);
1643 if (kgdb_io_ops) {
1644 spin_unlock(&kgdb_registration_lock);
1646 printk(KERN_ERR "kgdb: Another I/O driver is already "
1647 "registered with KGDB.\n");
1648 return -EBUSY;
1651 if (new_kgdb_io_ops->init) {
1652 err = new_kgdb_io_ops->init();
1653 if (err) {
1654 spin_unlock(&kgdb_registration_lock);
1655 return err;
1659 kgdb_io_ops = new_kgdb_io_ops;
1661 spin_unlock(&kgdb_registration_lock);
1663 printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
1664 new_kgdb_io_ops->name);
1666 /* Arm KGDB now. */
1667 kgdb_register_callbacks();
1669 if (kgdb_break_asap)
1670 kgdb_initial_breakpoint();
1672 return 0;
1674 EXPORT_SYMBOL_GPL(kgdb_register_io_module);
1677 * kkgdb_unregister_io_module - unregister KGDB IO module
1678 * @old_kgdb_io_ops: the io ops vector
1680 * Unregister it with the KGDB core.
1682 void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
1684 BUG_ON(kgdb_connected);
1687 * KGDB is no longer able to communicate out, so
1688 * unregister our callbacks and reset state.
1690 kgdb_unregister_callbacks();
1692 spin_lock(&kgdb_registration_lock);
1694 WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
1695 kgdb_io_ops = NULL;
1697 spin_unlock(&kgdb_registration_lock);
1699 printk(KERN_INFO
1700 "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
1701 old_kgdb_io_ops->name);
1703 EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
1706 * kgdb_breakpoint - generate breakpoint exception
1708 * This function will generate a breakpoint exception. It is used at the
1709 * beginning of a program to sync up with a debugger and can be used
1710 * otherwise as a quick means to stop program execution and "break" into
1711 * the debugger.
1713 void kgdb_breakpoint(void)
1715 atomic_set(&kgdb_setting_breakpoint, 1);
1716 wmb(); /* Sync point before breakpoint */
1717 arch_kgdb_breakpoint();
1718 wmb(); /* Sync point after breakpoint */
1719 atomic_set(&kgdb_setting_breakpoint, 0);
1721 EXPORT_SYMBOL_GPL(kgdb_breakpoint);
1723 static int __init opt_kgdb_wait(char *str)
1725 kgdb_break_asap = 1;
1727 if (kgdb_io_module_registered)
1728 kgdb_initial_breakpoint();
1730 return 0;
1733 early_param("kgdbwait", opt_kgdb_wait);