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>
51 #include <asm/cacheflush.h>
52 #include <asm/byteorder.h>
53 #include <asm/atomic.h>
54 #include <asm/system.h>
56 static int kgdb_break_asap
;
65 long kgdb_usethreadid
;
66 struct pt_regs
*linux_regs
;
69 static struct debuggerinfo_struct
{
71 struct task_struct
*task
;
75 * kgdb_connected - Is a host GDB connected to us?
78 EXPORT_SYMBOL_GPL(kgdb_connected
);
80 /* All the KGDB handlers are installed */
81 static int kgdb_io_module_registered
;
83 /* Guard for recursive entry */
84 static int exception_level
;
86 static struct kgdb_io
*kgdb_io_ops
;
87 static DEFINE_SPINLOCK(kgdb_registration_lock
);
89 /* kgdb console driver is loaded */
90 static int kgdb_con_registered
;
91 /* determine if kgdb console output should be used */
92 static int kgdb_use_con
;
94 static int __init
opt_kgdb_con(char *str
)
100 early_param("kgdbcon", opt_kgdb_con
);
102 module_param(kgdb_use_con
, int, 0644);
105 * Holds information about breakpoints in a kernel. These breakpoints are
106 * added and removed by gdb.
108 static struct kgdb_bkpt kgdb_break
[KGDB_MAX_BREAKPOINTS
] = {
109 [0 ... KGDB_MAX_BREAKPOINTS
-1] = { .state
= BP_UNDEFINED
}
113 * The CPU# of the active CPU, or -1 if none:
115 atomic_t kgdb_active
= ATOMIC_INIT(-1);
118 * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
119 * bootup code (which might not have percpu set up yet):
121 static atomic_t passive_cpu_wait
[NR_CPUS
];
122 static atomic_t cpu_in_kgdb
[NR_CPUS
];
123 atomic_t kgdb_setting_breakpoint
;
125 struct task_struct
*kgdb_usethread
;
126 struct task_struct
*kgdb_contthread
;
128 int kgdb_single_step
;
130 /* Our I/O buffers. */
131 static char remcom_in_buffer
[BUFMAX
];
132 static char remcom_out_buffer
[BUFMAX
];
134 /* Storage for the registers, in GDB format. */
135 static unsigned long gdb_regs
[(NUMREGBYTES
+
136 sizeof(unsigned long) - 1) /
137 sizeof(unsigned long)];
139 /* to keep track of the CPU which is doing the single stepping*/
140 atomic_t kgdb_cpu_doing_single_step
= ATOMIC_INIT(-1);
143 * If you are debugging a problem where roundup (the collection of
144 * all other CPUs) is a problem [this should be extremely rare],
145 * then use the nokgdbroundup option to avoid roundup. In that case
146 * the other CPUs might interfere with your debugging context, so
147 * use this with care:
149 int kgdb_do_roundup
= 1;
151 static int __init
opt_nokgdbroundup(char *str
)
158 early_param("nokgdbroundup", opt_nokgdbroundup
);
161 * Finally, some KGDB code :-)
165 * Weak aliases for breakpoint management,
166 * can be overriden by architectures when needed:
168 int __weak
kgdb_validate_break_address(unsigned long addr
)
170 char tmp_variable
[BREAK_INSTR_SIZE
];
172 return probe_kernel_read(tmp_variable
, (char *)addr
, BREAK_INSTR_SIZE
);
175 int __weak
kgdb_arch_set_breakpoint(unsigned long addr
, char *saved_instr
)
179 err
= probe_kernel_read(saved_instr
, (char *)addr
, BREAK_INSTR_SIZE
);
183 return probe_kernel_write((char *)addr
, arch_kgdb_ops
.gdb_bpt_instr
,
187 int __weak
kgdb_arch_remove_breakpoint(unsigned long addr
, char *bundle
)
189 return probe_kernel_write((char *)addr
,
190 (char *)bundle
, BREAK_INSTR_SIZE
);
193 unsigned long __weak
kgdb_arch_pc(int exception
, struct pt_regs
*regs
)
195 return instruction_pointer(regs
);
198 int __weak
kgdb_arch_init(void)
203 int __weak
kgdb_skipexception(int exception
, struct pt_regs
*regs
)
209 kgdb_post_primary_code(struct pt_regs
*regs
, int e_vector
, int err_code
)
215 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
216 * @regs: Current &struct pt_regs.
218 * This function will be called if the particular architecture must
219 * disable hardware debugging while it is processing gdb packets or
220 * handling exception.
222 void __weak
kgdb_disable_hw_debug(struct pt_regs
*regs
)
227 * GDB remote protocol parser:
230 static const char hexchars
[] = "0123456789abcdef";
232 static int hex(char ch
)
234 if ((ch
>= 'a') && (ch
<= 'f'))
235 return ch
- 'a' + 10;
236 if ((ch
>= '0') && (ch
<= '9'))
238 if ((ch
>= 'A') && (ch
<= 'F'))
239 return ch
- 'A' + 10;
243 /* scan for the sequence $<data>#<checksum> */
244 static void get_packet(char *buffer
)
246 unsigned char checksum
;
247 unsigned char xmitcsum
;
253 * Spin and wait around for the start character, ignore all
256 while ((ch
= (kgdb_io_ops
->read_char())) != '$')
266 * now, read until a # or end of buffer is found:
268 while (count
< (BUFMAX
- 1)) {
269 ch
= kgdb_io_ops
->read_char();
272 checksum
= checksum
+ ch
;
279 xmitcsum
= hex(kgdb_io_ops
->read_char()) << 4;
280 xmitcsum
+= hex(kgdb_io_ops
->read_char());
282 if (checksum
!= xmitcsum
)
283 /* failed checksum */
284 kgdb_io_ops
->write_char('-');
286 /* successful transfer */
287 kgdb_io_ops
->write_char('+');
288 if (kgdb_io_ops
->flush
)
289 kgdb_io_ops
->flush();
291 } while (checksum
!= xmitcsum
);
295 * Send the packet in buffer.
296 * Check for gdb connection if asked for.
298 static void put_packet(char *buffer
)
300 unsigned char checksum
;
305 * $<packet info>#<checksum>.
308 kgdb_io_ops
->write_char('$');
312 while ((ch
= buffer
[count
])) {
313 kgdb_io_ops
->write_char(ch
);
318 kgdb_io_ops
->write_char('#');
319 kgdb_io_ops
->write_char(hexchars
[checksum
>> 4]);
320 kgdb_io_ops
->write_char(hexchars
[checksum
& 0xf]);
321 if (kgdb_io_ops
->flush
)
322 kgdb_io_ops
->flush();
324 /* Now see what we get in reply. */
325 ch
= kgdb_io_ops
->read_char();
328 ch
= kgdb_io_ops
->read_char();
330 /* If we get an ACK, we are done. */
335 * If we get the start of another packet, this means
336 * that GDB is attempting to reconnect. We will NAK
337 * the packet being sent, and stop trying to send this
341 kgdb_io_ops
->write_char('-');
342 if (kgdb_io_ops
->flush
)
343 kgdb_io_ops
->flush();
349 static char *pack_hex_byte(char *pkt
, u8 byte
)
351 *pkt
++ = hexchars
[byte
>> 4];
352 *pkt
++ = hexchars
[byte
& 0xf];
358 * Convert the memory pointed to by mem into hex, placing result in buf.
359 * Return a pointer to the last char put in buf (null). May return an error.
361 int kgdb_mem2hex(char *mem
, char *buf
, int count
)
367 * We use the upper half of buf as an intermediate buffer for the
368 * raw memory copy. Hex conversion will work against this one.
372 err
= probe_kernel_read(tmp
, mem
, count
);
375 buf
= pack_hex_byte(buf
, *tmp
);
387 * Copy the binary array pointed to by buf into mem. Fix $, #, and
388 * 0x7d escaped with 0x7d. Return a pointer to the character after
389 * the last byte written.
391 static int kgdb_ebin2mem(char *buf
, char *mem
, int count
)
396 while (count
-- > 0) {
401 err
= probe_kernel_write(mem
, &c
, 1);
412 * Convert the hex array pointed to by buf into binary to be placed in mem.
413 * Return a pointer to the character AFTER the last byte written.
414 * May return an error.
416 int kgdb_hex2mem(char *buf
, char *mem
, int count
)
422 * We use the upper half of buf as an intermediate buffer for the
423 * raw memory that is converted from hex.
425 tmp_raw
= buf
+ count
* 2;
427 tmp_hex
= tmp_raw
- 1;
428 while (tmp_hex
>= buf
) {
430 *tmp_raw
= hex(*tmp_hex
--);
431 *tmp_raw
|= hex(*tmp_hex
--) << 4;
434 return probe_kernel_write(mem
, tmp_raw
, count
);
438 * While we find nice hex chars, build a long_val.
439 * Return number of chars processed.
441 int kgdb_hex2long(char **ptr
, long *long_val
)
449 hex_val
= hex(**ptr
);
453 *long_val
= (*long_val
<< 4) | hex_val
;
461 /* Write memory due to an 'M' or 'X' packet. */
462 static int write_mem_msg(int binary
)
464 char *ptr
= &remcom_in_buffer
[1];
466 unsigned long length
;
469 if (kgdb_hex2long(&ptr
, &addr
) > 0 && *(ptr
++) == ',' &&
470 kgdb_hex2long(&ptr
, &length
) > 0 && *(ptr
++) == ':') {
472 err
= kgdb_ebin2mem(ptr
, (char *)addr
, length
);
474 err
= kgdb_hex2mem(ptr
, (char *)addr
, length
);
477 if (CACHE_FLUSH_IS_SAFE
)
478 flush_icache_range(addr
, addr
+ length
+ 1);
485 static void error_packet(char *pkt
, int error
)
489 pkt
[1] = hexchars
[(error
/ 10)];
490 pkt
[2] = hexchars
[(error
% 10)];
495 * Thread ID accessors. We represent a flat TID space to GDB, where
496 * the per CPU idle threads (which under Linux all have PID 0) are
497 * remapped to negative TIDs.
500 #define BUF_THREAD_ID_SIZE 16
502 static char *pack_threadid(char *pkt
, unsigned char *id
)
506 limit
= pkt
+ BUF_THREAD_ID_SIZE
;
508 pkt
= pack_hex_byte(pkt
, *id
++);
513 static void int_to_threadref(unsigned char *id
, int value
)
518 scan
= (unsigned char *)id
;
521 *scan
++ = (value
>> 24) & 0xff;
522 *scan
++ = (value
>> 16) & 0xff;
523 *scan
++ = (value
>> 8) & 0xff;
524 *scan
++ = (value
& 0xff);
527 static struct task_struct
*getthread(struct pt_regs
*regs
, int tid
)
530 * Non-positive TIDs are remapped idle tasks:
533 return idle_task(-tid
);
536 * find_task_by_pid_ns() does not take the tasklist lock anymore
537 * but is nicely RCU locked - hence is a pretty resilient
540 return find_task_by_pid_ns(tid
, &init_pid_ns
);
544 * CPU debug state control:
548 static void kgdb_wait(struct pt_regs
*regs
)
553 local_irq_save(flags
);
554 cpu
= raw_smp_processor_id();
555 kgdb_info
[cpu
].debuggerinfo
= regs
;
556 kgdb_info
[cpu
].task
= current
;
558 * Make sure the above info reaches the primary CPU before
559 * our cpu_in_kgdb[] flag setting does:
562 atomic_set(&cpu_in_kgdb
[cpu
], 1);
565 * The primary CPU must be active to enter here, but this is
566 * guard in case the primary CPU had not been selected if
567 * this was an entry via nmi.
569 while (atomic_read(&kgdb_active
) == -1)
572 /* Wait till primary CPU goes completely into the debugger. */
573 while (!atomic_read(&cpu_in_kgdb
[atomic_read(&kgdb_active
)]))
576 /* Wait till primary CPU is done with debugging */
577 while (atomic_read(&passive_cpu_wait
[cpu
]))
580 kgdb_info
[cpu
].debuggerinfo
= NULL
;
581 kgdb_info
[cpu
].task
= NULL
;
583 /* fix up hardware debug registers on local cpu */
584 if (arch_kgdb_ops
.correct_hw_break
)
585 arch_kgdb_ops
.correct_hw_break();
587 /* Signal the primary CPU that we are done: */
588 atomic_set(&cpu_in_kgdb
[cpu
], 0);
589 clocksource_touch_watchdog();
590 local_irq_restore(flags
);
595 * Some architectures need cache flushes when we set/clear a
598 static void kgdb_flush_swbreak_addr(unsigned long addr
)
600 if (!CACHE_FLUSH_IS_SAFE
)
604 flush_cache_range(current
->mm
->mmap_cache
,
605 addr
, addr
+ BREAK_INSTR_SIZE
);
607 flush_icache_range(addr
, addr
+ BREAK_INSTR_SIZE
);
612 * SW breakpoint management:
614 static int kgdb_activate_sw_breakpoints(void)
620 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
621 if (kgdb_break
[i
].state
!= BP_SET
)
624 addr
= kgdb_break
[i
].bpt_addr
;
625 error
= kgdb_arch_set_breakpoint(addr
,
626 kgdb_break
[i
].saved_instr
);
630 kgdb_flush_swbreak_addr(addr
);
631 kgdb_break
[i
].state
= BP_ACTIVE
;
636 static int kgdb_set_sw_break(unsigned long addr
)
638 int err
= kgdb_validate_break_address(addr
);
645 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
646 if ((kgdb_break
[i
].state
== BP_SET
) &&
647 (kgdb_break
[i
].bpt_addr
== addr
))
650 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
651 if (kgdb_break
[i
].state
== BP_REMOVED
&&
652 kgdb_break
[i
].bpt_addr
== addr
) {
659 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
660 if (kgdb_break
[i
].state
== BP_UNDEFINED
) {
670 kgdb_break
[breakno
].state
= BP_SET
;
671 kgdb_break
[breakno
].type
= BP_BREAKPOINT
;
672 kgdb_break
[breakno
].bpt_addr
= addr
;
677 static int kgdb_deactivate_sw_breakpoints(void)
683 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
684 if (kgdb_break
[i
].state
!= BP_ACTIVE
)
686 addr
= kgdb_break
[i
].bpt_addr
;
687 error
= kgdb_arch_remove_breakpoint(addr
,
688 kgdb_break
[i
].saved_instr
);
692 kgdb_flush_swbreak_addr(addr
);
693 kgdb_break
[i
].state
= BP_SET
;
698 static int kgdb_remove_sw_break(unsigned long addr
)
702 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
703 if ((kgdb_break
[i
].state
== BP_SET
) &&
704 (kgdb_break
[i
].bpt_addr
== addr
)) {
705 kgdb_break
[i
].state
= BP_REMOVED
;
712 int kgdb_isremovedbreak(unsigned long addr
)
716 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
717 if ((kgdb_break
[i
].state
== BP_REMOVED
) &&
718 (kgdb_break
[i
].bpt_addr
== addr
))
724 int remove_all_break(void)
730 /* Clear memory breakpoints. */
731 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
732 if (kgdb_break
[i
].state
!= BP_SET
)
734 addr
= kgdb_break
[i
].bpt_addr
;
735 error
= kgdb_arch_remove_breakpoint(addr
,
736 kgdb_break
[i
].saved_instr
);
739 kgdb_break
[i
].state
= BP_REMOVED
;
742 /* Clear hardware breakpoints. */
743 if (arch_kgdb_ops
.remove_all_hw_break
)
744 arch_kgdb_ops
.remove_all_hw_break();
750 * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs:
752 static inline int shadow_pid(int realpid
)
757 return -1-raw_smp_processor_id();
760 static char gdbmsgbuf
[BUFMAX
+ 1];
762 static void kgdb_msg_write(const char *s
, int len
)
771 /* Fill and send buffers... */
773 bufptr
= gdbmsgbuf
+ 1;
775 /* Calculate how many this time */
776 if ((len
<< 1) > (BUFMAX
- 2))
777 wcount
= (BUFMAX
- 2) >> 1;
781 /* Pack in hex chars */
782 for (i
= 0; i
< wcount
; i
++)
783 bufptr
= pack_hex_byte(bufptr
, s
[i
]);
791 put_packet(gdbmsgbuf
);
796 * Return true if there is a valid kgdb I/O module. Also if no
797 * debugger is attached a message can be printed to the console about
798 * waiting for the debugger to attach.
800 * The print_wait argument is only to be true when called from inside
801 * the core kgdb_handle_exception, because it will wait for the
802 * debugger to attach.
804 static int kgdb_io_ready(int print_wait
)
810 if (atomic_read(&kgdb_setting_breakpoint
))
813 printk(KERN_CRIT
"KGDB: Waiting for remote debugger\n");
818 * All the functions that start with gdb_cmd are the various
819 * operations to implement the handlers for the gdbserial protocol
820 * where KGDB is communicating with an external debugger
823 /* Handle the '?' status packets */
824 static void gdb_cmd_status(struct kgdb_state
*ks
)
827 * We know that this packet is only sent
828 * during initial connect. So to be safe,
829 * we clear out our breakpoints now in case
830 * GDB is reconnecting.
834 remcom_out_buffer
[0] = 'S';
835 pack_hex_byte(&remcom_out_buffer
[1], ks
->signo
);
838 /* Handle the 'g' get registers request */
839 static void gdb_cmd_getregs(struct kgdb_state
*ks
)
841 struct task_struct
*thread
;
842 void *local_debuggerinfo
;
845 thread
= kgdb_usethread
;
847 thread
= kgdb_info
[ks
->cpu
].task
;
848 local_debuggerinfo
= kgdb_info
[ks
->cpu
].debuggerinfo
;
850 local_debuggerinfo
= NULL
;
851 for (i
= 0; i
< NR_CPUS
; i
++) {
853 * Try to find the task on some other
854 * or possibly this node if we do not
855 * find the matching task then we try
856 * to approximate the results.
858 if (thread
== kgdb_info
[i
].task
)
859 local_debuggerinfo
= kgdb_info
[i
].debuggerinfo
;
864 * All threads that don't have debuggerinfo should be
865 * in __schedule() sleeping, since all other CPUs
866 * are in kgdb_wait, and thus have debuggerinfo.
868 if (local_debuggerinfo
) {
869 pt_regs_to_gdb_regs(gdb_regs
, local_debuggerinfo
);
872 * Pull stuff saved during switch_to; nothing
873 * else is accessible (or even particularly
876 * This should be enough for a stack trace.
878 sleeping_thread_to_gdb_regs(gdb_regs
, thread
);
880 kgdb_mem2hex((char *)gdb_regs
, remcom_out_buffer
, NUMREGBYTES
);
883 /* Handle the 'G' set registers request */
884 static void gdb_cmd_setregs(struct kgdb_state
*ks
)
886 kgdb_hex2mem(&remcom_in_buffer
[1], (char *)gdb_regs
, NUMREGBYTES
);
888 if (kgdb_usethread
&& kgdb_usethread
!= current
) {
889 error_packet(remcom_out_buffer
, -EINVAL
);
891 gdb_regs_to_pt_regs(gdb_regs
, ks
->linux_regs
);
892 strcpy(remcom_out_buffer
, "OK");
896 /* Handle the 'm' memory read bytes */
897 static void gdb_cmd_memread(struct kgdb_state
*ks
)
899 char *ptr
= &remcom_in_buffer
[1];
900 unsigned long length
;
904 if (kgdb_hex2long(&ptr
, &addr
) > 0 && *ptr
++ == ',' &&
905 kgdb_hex2long(&ptr
, &length
) > 0) {
906 err
= kgdb_mem2hex((char *)addr
, remcom_out_buffer
, length
);
908 error_packet(remcom_out_buffer
, err
);
910 error_packet(remcom_out_buffer
, -EINVAL
);
914 /* Handle the 'M' memory write bytes */
915 static void gdb_cmd_memwrite(struct kgdb_state
*ks
)
917 int err
= write_mem_msg(0);
920 error_packet(remcom_out_buffer
, err
);
922 strcpy(remcom_out_buffer
, "OK");
925 /* Handle the 'X' memory binary write bytes */
926 static void gdb_cmd_binwrite(struct kgdb_state
*ks
)
928 int err
= write_mem_msg(1);
931 error_packet(remcom_out_buffer
, err
);
933 strcpy(remcom_out_buffer
, "OK");
936 /* Handle the 'D' or 'k', detach or kill packets */
937 static void gdb_cmd_detachkill(struct kgdb_state
*ks
)
941 /* The detach case */
942 if (remcom_in_buffer
[0] == 'D') {
943 error
= remove_all_break();
945 error_packet(remcom_out_buffer
, error
);
947 strcpy(remcom_out_buffer
, "OK");
950 put_packet(remcom_out_buffer
);
953 * Assume the kill case, with no exit code checking,
954 * trying to force detach the debugger:
961 /* Handle the 'R' reboot packets */
962 static int gdb_cmd_reboot(struct kgdb_state
*ks
)
964 /* For now, only honor R0 */
965 if (strcmp(remcom_in_buffer
, "R0") == 0) {
966 printk(KERN_CRIT
"Executing emergency reboot\n");
967 strcpy(remcom_out_buffer
, "OK");
968 put_packet(remcom_out_buffer
);
971 * Execution should not return from
972 * machine_emergency_restart()
974 machine_emergency_restart();
982 /* Handle the 'q' query packets */
983 static void gdb_cmd_query(struct kgdb_state
*ks
)
985 struct task_struct
*thread
;
986 unsigned char thref
[8];
990 switch (remcom_in_buffer
[1]) {
993 if (memcmp(remcom_in_buffer
+ 2, "ThreadInfo", 10)) {
994 error_packet(remcom_out_buffer
, -EINVAL
);
998 if (remcom_in_buffer
[1] == 'f')
1001 remcom_out_buffer
[0] = 'm';
1002 ptr
= remcom_out_buffer
+ 1;
1004 for (i
= 0; i
< 17; ks
->threadid
++) {
1005 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
1007 int_to_threadref(thref
, ks
->threadid
);
1008 pack_threadid(ptr
, thref
);
1009 ptr
+= BUF_THREAD_ID_SIZE
;
1018 /* Current thread id */
1019 strcpy(remcom_out_buffer
, "QC");
1020 ks
->threadid
= shadow_pid(current
->pid
);
1021 int_to_threadref(thref
, ks
->threadid
);
1022 pack_threadid(remcom_out_buffer
+ 2, thref
);
1025 if (memcmp(remcom_in_buffer
+ 1, "ThreadExtraInfo,", 16)) {
1026 error_packet(remcom_out_buffer
, -EINVAL
);
1030 ptr
= remcom_in_buffer
+ 17;
1031 kgdb_hex2long(&ptr
, &ks
->threadid
);
1032 if (!getthread(ks
->linux_regs
, ks
->threadid
)) {
1033 error_packet(remcom_out_buffer
, -EINVAL
);
1036 if (ks
->threadid
> 0) {
1037 kgdb_mem2hex(getthread(ks
->linux_regs
,
1038 ks
->threadid
)->comm
,
1039 remcom_out_buffer
, 16);
1041 static char tmpstr
[23 + BUF_THREAD_ID_SIZE
];
1043 sprintf(tmpstr
, "Shadow task %d for pid 0",
1044 (int)(-ks
->threadid
-1));
1045 kgdb_mem2hex(tmpstr
, remcom_out_buffer
, strlen(tmpstr
));
1051 /* Handle the 'H' task query packets */
1052 static void gdb_cmd_task(struct kgdb_state
*ks
)
1054 struct task_struct
*thread
;
1057 switch (remcom_in_buffer
[1]) {
1059 ptr
= &remcom_in_buffer
[2];
1060 kgdb_hex2long(&ptr
, &ks
->threadid
);
1061 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
1062 if (!thread
&& ks
->threadid
> 0) {
1063 error_packet(remcom_out_buffer
, -EINVAL
);
1066 kgdb_usethread
= thread
;
1067 ks
->kgdb_usethreadid
= ks
->threadid
;
1068 strcpy(remcom_out_buffer
, "OK");
1071 ptr
= &remcom_in_buffer
[2];
1072 kgdb_hex2long(&ptr
, &ks
->threadid
);
1073 if (!ks
->threadid
) {
1074 kgdb_contthread
= NULL
;
1076 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
1077 if (!thread
&& ks
->threadid
> 0) {
1078 error_packet(remcom_out_buffer
, -EINVAL
);
1081 kgdb_contthread
= thread
;
1083 strcpy(remcom_out_buffer
, "OK");
1088 /* Handle the 'T' thread query packets */
1089 static void gdb_cmd_thread(struct kgdb_state
*ks
)
1091 char *ptr
= &remcom_in_buffer
[1];
1092 struct task_struct
*thread
;
1094 kgdb_hex2long(&ptr
, &ks
->threadid
);
1095 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
1097 strcpy(remcom_out_buffer
, "OK");
1099 error_packet(remcom_out_buffer
, -EINVAL
);
1102 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
1103 static void gdb_cmd_break(struct kgdb_state
*ks
)
1106 * Since GDB-5.3, it's been drafted that '0' is a software
1107 * breakpoint, '1' is a hardware breakpoint, so let's do that.
1109 char *bpt_type
= &remcom_in_buffer
[1];
1110 char *ptr
= &remcom_in_buffer
[2];
1112 unsigned long length
;
1115 if (arch_kgdb_ops
.set_hw_breakpoint
&& *bpt_type
>= '1') {
1117 if (*bpt_type
> '4')
1120 if (*bpt_type
!= '0' && *bpt_type
!= '1')
1126 * Test if this is a hardware breakpoint, and
1129 if (*bpt_type
== '1' && !(arch_kgdb_ops
.flags
& KGDB_HW_BREAKPOINT
))
1133 if (*(ptr
++) != ',') {
1134 error_packet(remcom_out_buffer
, -EINVAL
);
1137 if (!kgdb_hex2long(&ptr
, &addr
)) {
1138 error_packet(remcom_out_buffer
, -EINVAL
);
1141 if (*(ptr
++) != ',' ||
1142 !kgdb_hex2long(&ptr
, &length
)) {
1143 error_packet(remcom_out_buffer
, -EINVAL
);
1147 if (remcom_in_buffer
[0] == 'Z' && *bpt_type
== '0')
1148 error
= kgdb_set_sw_break(addr
);
1149 else if (remcom_in_buffer
[0] == 'z' && *bpt_type
== '0')
1150 error
= kgdb_remove_sw_break(addr
);
1151 else if (remcom_in_buffer
[0] == 'Z')
1152 error
= arch_kgdb_ops
.set_hw_breakpoint(addr
,
1153 (int)length
, *bpt_type
- '0');
1154 else if (remcom_in_buffer
[0] == 'z')
1155 error
= arch_kgdb_ops
.remove_hw_breakpoint(addr
,
1156 (int) length
, *bpt_type
- '0');
1159 strcpy(remcom_out_buffer
, "OK");
1161 error_packet(remcom_out_buffer
, error
);
1164 /* Handle the 'C' signal / exception passing packets */
1165 static int gdb_cmd_exception_pass(struct kgdb_state
*ks
)
1167 /* C09 == pass exception
1168 * C15 == detach kgdb, pass exception
1170 if (remcom_in_buffer
[1] == '0' && remcom_in_buffer
[2] == '9') {
1172 ks
->pass_exception
= 1;
1173 remcom_in_buffer
[0] = 'c';
1175 } else if (remcom_in_buffer
[1] == '1' && remcom_in_buffer
[2] == '5') {
1177 ks
->pass_exception
= 1;
1178 remcom_in_buffer
[0] = 'D';
1184 error_packet(remcom_out_buffer
, -EINVAL
);
1188 /* Indicate fall through */
1193 * This function performs all gdbserial command procesing
1195 static int gdb_serial_stub(struct kgdb_state
*ks
)
1200 /* Clear the out buffer. */
1201 memset(remcom_out_buffer
, 0, sizeof(remcom_out_buffer
));
1203 if (kgdb_connected
) {
1204 unsigned char thref
[8];
1207 /* Reply to host that an exception has occurred */
1208 ptr
= remcom_out_buffer
;
1210 ptr
= pack_hex_byte(ptr
, ks
->signo
);
1211 ptr
+= strlen(strcpy(ptr
, "thread:"));
1212 int_to_threadref(thref
, shadow_pid(current
->pid
));
1213 ptr
= pack_threadid(ptr
, thref
);
1215 put_packet(remcom_out_buffer
);
1218 kgdb_usethread
= kgdb_info
[ks
->cpu
].task
;
1219 ks
->kgdb_usethreadid
= shadow_pid(kgdb_info
[ks
->cpu
].task
->pid
);
1220 ks
->pass_exception
= 0;
1225 /* Clear the out buffer. */
1226 memset(remcom_out_buffer
, 0, sizeof(remcom_out_buffer
));
1228 get_packet(remcom_in_buffer
);
1230 switch (remcom_in_buffer
[0]) {
1231 case '?': /* gdbserial status */
1234 case 'g': /* return the value of the CPU registers */
1235 gdb_cmd_getregs(ks
);
1237 case 'G': /* set the value of the CPU registers - return OK */
1238 gdb_cmd_setregs(ks
);
1240 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
1241 gdb_cmd_memread(ks
);
1243 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1244 gdb_cmd_memwrite(ks
);
1246 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1247 gdb_cmd_binwrite(ks
);
1249 /* kill or detach. KGDB should treat this like a
1252 case 'D': /* Debugger detach */
1253 case 'k': /* Debugger detach via kill */
1254 gdb_cmd_detachkill(ks
);
1255 goto default_handle
;
1256 case 'R': /* Reboot */
1257 if (gdb_cmd_reboot(ks
))
1258 goto default_handle
;
1260 case 'q': /* query command */
1263 case 'H': /* task related */
1266 case 'T': /* Query thread status */
1269 case 'z': /* Break point remove */
1270 case 'Z': /* Break point set */
1273 case 'C': /* Exception passing */
1274 tmp
= gdb_cmd_exception_pass(ks
);
1276 goto default_handle
;
1279 /* Fall through on tmp < 0 */
1280 case 'c': /* Continue packet */
1281 case 's': /* Single step packet */
1282 if (kgdb_contthread
&& kgdb_contthread
!= current
) {
1283 /* Can't switch threads in kgdb */
1284 error_packet(remcom_out_buffer
, -EINVAL
);
1287 kgdb_activate_sw_breakpoints();
1288 /* Fall through to default processing */
1291 error
= kgdb_arch_handle_exception(ks
->ex_vector
,
1298 * Leave cmd processing on error, detach,
1299 * kill, continue, or single step.
1301 if (error
>= 0 || remcom_in_buffer
[0] == 'D' ||
1302 remcom_in_buffer
[0] == 'k') {
1309 /* reply to the request */
1310 put_packet(remcom_out_buffer
);
1314 if (ks
->pass_exception
)
1319 static int kgdb_reenter_check(struct kgdb_state
*ks
)
1323 if (atomic_read(&kgdb_active
) != raw_smp_processor_id())
1326 /* Panic on recursive debugger calls: */
1328 addr
= kgdb_arch_pc(ks
->ex_vector
, ks
->linux_regs
);
1329 kgdb_deactivate_sw_breakpoints();
1332 * If the break point removed ok at the place exception
1333 * occurred, try to recover and print a warning to the end
1334 * user because the user planted a breakpoint in a place that
1335 * KGDB needs in order to function.
1337 if (kgdb_remove_sw_break(addr
) == 0) {
1338 exception_level
= 0;
1339 kgdb_skipexception(ks
->ex_vector
, ks
->linux_regs
);
1340 kgdb_activate_sw_breakpoints();
1341 printk(KERN_CRIT
"KGDB: re-enter error: breakpoint removed %lx\n",
1348 kgdb_skipexception(ks
->ex_vector
, ks
->linux_regs
);
1350 if (exception_level
> 1) {
1352 panic("Recursive entry to debugger");
1355 printk(KERN_CRIT
"KGDB: re-enter exception: ALL breakpoints killed\n");
1357 panic("Recursive entry to debugger");
1363 * kgdb_handle_exception() - main entry point from a kernel exception
1365 * Locking hierarchy:
1366 * interface locks, if any (begin_session)
1367 * kgdb lock (kgdb_active)
1370 kgdb_handle_exception(int evector
, int signo
, int ecode
, struct pt_regs
*regs
)
1372 struct kgdb_state kgdb_var
;
1373 struct kgdb_state
*ks
= &kgdb_var
;
1374 unsigned long flags
;
1378 ks
->cpu
= raw_smp_processor_id();
1379 ks
->ex_vector
= evector
;
1381 ks
->ex_vector
= evector
;
1382 ks
->err_code
= ecode
;
1383 ks
->kgdb_usethreadid
= 0;
1384 ks
->linux_regs
= regs
;
1386 if (kgdb_reenter_check(ks
))
1387 return 0; /* Ouch, double exception ! */
1391 * Interrupts will be restored by the 'trap return' code, except when
1394 local_irq_save(flags
);
1396 cpu
= raw_smp_processor_id();
1399 * Acquire the kgdb_active lock:
1401 while (atomic_cmpxchg(&kgdb_active
, -1, cpu
) != -1)
1405 * Do not start the debugger connection on this CPU if the last
1406 * instance of the exception handler wanted to come into the
1407 * debugger on a different CPU via a single step
1409 if (atomic_read(&kgdb_cpu_doing_single_step
) != -1 &&
1410 atomic_read(&kgdb_cpu_doing_single_step
) != cpu
) {
1412 atomic_set(&kgdb_active
, -1);
1413 clocksource_touch_watchdog();
1414 local_irq_restore(flags
);
1419 if (!kgdb_io_ready(1)) {
1421 goto kgdb_restore
; /* No I/O connection, so resume the system */
1425 * Don't enter if we have hit a removed breakpoint.
1427 if (kgdb_skipexception(ks
->ex_vector
, ks
->linux_regs
))
1430 /* Call the I/O driver's pre_exception routine */
1431 if (kgdb_io_ops
->pre_exception
)
1432 kgdb_io_ops
->pre_exception();
1434 kgdb_info
[ks
->cpu
].debuggerinfo
= ks
->linux_regs
;
1435 kgdb_info
[ks
->cpu
].task
= current
;
1437 kgdb_disable_hw_debug(ks
->linux_regs
);
1440 * Get the passive CPU lock which will hold all the non-primary
1441 * CPU in a spin state while the debugger is active
1443 if (!kgdb_single_step
|| !kgdb_contthread
) {
1444 for (i
= 0; i
< NR_CPUS
; i
++)
1445 atomic_set(&passive_cpu_wait
[i
], 1);
1449 /* Signal the other CPUs to enter kgdb_wait() */
1450 if ((!kgdb_single_step
|| !kgdb_contthread
) && kgdb_do_roundup
)
1451 kgdb_roundup_cpus(flags
);
1455 * spin_lock code is good enough as a barrier so we don't
1458 atomic_set(&cpu_in_kgdb
[ks
->cpu
], 1);
1461 * Wait for the other CPUs to be notified and be waiting for us:
1463 for_each_online_cpu(i
) {
1464 while (!atomic_read(&cpu_in_kgdb
[i
]))
1469 * At this point the primary processor is completely
1470 * in the debugger and all secondary CPUs are quiescent
1472 kgdb_post_primary_code(ks
->linux_regs
, ks
->ex_vector
, ks
->err_code
);
1473 kgdb_deactivate_sw_breakpoints();
1474 kgdb_single_step
= 0;
1475 kgdb_contthread
= NULL
;
1476 exception_level
= 0;
1478 /* Talk to debugger with gdbserial protocol */
1479 error
= gdb_serial_stub(ks
);
1481 /* Call the I/O driver's post_exception routine */
1482 if (kgdb_io_ops
->post_exception
)
1483 kgdb_io_ops
->post_exception();
1485 kgdb_info
[ks
->cpu
].debuggerinfo
= NULL
;
1486 kgdb_info
[ks
->cpu
].task
= NULL
;
1487 atomic_set(&cpu_in_kgdb
[ks
->cpu
], 0);
1489 if (!kgdb_single_step
|| !kgdb_contthread
) {
1490 for (i
= NR_CPUS
-1; i
>= 0; i
--)
1491 atomic_set(&passive_cpu_wait
[i
], 0);
1493 * Wait till all the CPUs have quit
1494 * from the debugger.
1496 for_each_online_cpu(i
) {
1497 while (atomic_read(&cpu_in_kgdb
[i
]))
1503 /* Free kgdb_active */
1504 atomic_set(&kgdb_active
, -1);
1505 clocksource_touch_watchdog();
1506 local_irq_restore(flags
);
1511 int kgdb_nmicallback(int cpu
, void *regs
)
1514 if (!atomic_read(&cpu_in_kgdb
[cpu
]) &&
1515 atomic_read(&kgdb_active
) != cpu
) {
1516 kgdb_wait((struct pt_regs
*)regs
);
1523 void kgdb_console_write(struct console
*co
, const char *s
, unsigned count
)
1525 unsigned long flags
;
1527 /* If we're debugging, or KGDB has not connected, don't try
1529 if (!kgdb_connected
|| atomic_read(&kgdb_active
) != -1)
1532 local_irq_save(flags
);
1533 kgdb_msg_write(s
, count
);
1534 local_irq_restore(flags
);
1537 static struct console kgdbcons
= {
1539 .write
= kgdb_console_write
,
1540 .flags
= CON_PRINTBUFFER
| CON_ENABLED
,
1544 #ifdef CONFIG_MAGIC_SYSRQ
1545 static void sysrq_handle_gdb(int key
, struct tty_struct
*tty
)
1548 printk(KERN_CRIT
"ERROR: No KGDB I/O module available\n");
1551 if (!kgdb_connected
)
1552 printk(KERN_CRIT
"Entering KGDB\n");
1557 static struct sysrq_key_op sysrq_gdb_op
= {
1558 .handler
= sysrq_handle_gdb
,
1560 .action_msg
= "GDB",
1564 static void kgdb_register_callbacks(void)
1566 if (!kgdb_io_module_registered
) {
1567 kgdb_io_module_registered
= 1;
1569 #ifdef CONFIG_MAGIC_SYSRQ
1570 register_sysrq_key('g', &sysrq_gdb_op
);
1572 if (kgdb_use_con
&& !kgdb_con_registered
) {
1573 register_console(&kgdbcons
);
1574 kgdb_con_registered
= 1;
1579 static void kgdb_unregister_callbacks(void)
1582 * When this routine is called KGDB should unregister from the
1583 * panic handler and clean up, making sure it is not handling any
1584 * break exceptions at the time.
1586 if (kgdb_io_module_registered
) {
1587 kgdb_io_module_registered
= 0;
1589 #ifdef CONFIG_MAGIC_SYSRQ
1590 unregister_sysrq_key('g', &sysrq_gdb_op
);
1592 if (kgdb_con_registered
) {
1593 unregister_console(&kgdbcons
);
1594 kgdb_con_registered
= 0;
1599 static void kgdb_initial_breakpoint(void)
1601 kgdb_break_asap
= 0;
1603 printk(KERN_CRIT
"kgdb: Waiting for connection from remote gdb...\n");
1608 * kkgdb_register_io_module - register KGDB IO module
1609 * @new_kgdb_io_ops: the io ops vector
1611 * Register it with the KGDB core.
1613 int kgdb_register_io_module(struct kgdb_io
*new_kgdb_io_ops
)
1617 spin_lock(&kgdb_registration_lock
);
1620 spin_unlock(&kgdb_registration_lock
);
1622 printk(KERN_ERR
"kgdb: Another I/O driver is already "
1623 "registered with KGDB.\n");
1627 if (new_kgdb_io_ops
->init
) {
1628 err
= new_kgdb_io_ops
->init();
1630 spin_unlock(&kgdb_registration_lock
);
1635 kgdb_io_ops
= new_kgdb_io_ops
;
1637 spin_unlock(&kgdb_registration_lock
);
1639 printk(KERN_INFO
"kgdb: Registered I/O driver %s.\n",
1640 new_kgdb_io_ops
->name
);
1643 kgdb_register_callbacks();
1645 if (kgdb_break_asap
)
1646 kgdb_initial_breakpoint();
1650 EXPORT_SYMBOL_GPL(kgdb_register_io_module
);
1653 * kkgdb_unregister_io_module - unregister KGDB IO module
1654 * @old_kgdb_io_ops: the io ops vector
1656 * Unregister it with the KGDB core.
1658 void kgdb_unregister_io_module(struct kgdb_io
*old_kgdb_io_ops
)
1660 BUG_ON(kgdb_connected
);
1663 * KGDB is no longer able to communicate out, so
1664 * unregister our callbacks and reset state.
1666 kgdb_unregister_callbacks();
1668 spin_lock(&kgdb_registration_lock
);
1670 WARN_ON_ONCE(kgdb_io_ops
!= old_kgdb_io_ops
);
1673 spin_unlock(&kgdb_registration_lock
);
1676 "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
1677 old_kgdb_io_ops
->name
);
1679 EXPORT_SYMBOL_GPL(kgdb_unregister_io_module
);
1682 * kgdb_breakpoint - generate breakpoint exception
1684 * This function will generate a breakpoint exception. It is used at the
1685 * beginning of a program to sync up with a debugger and can be used
1686 * otherwise as a quick means to stop program execution and "break" into
1689 void kgdb_breakpoint(void)
1691 atomic_set(&kgdb_setting_breakpoint
, 1);
1692 wmb(); /* Sync point before breakpoint */
1693 arch_kgdb_breakpoint();
1694 wmb(); /* Sync point after breakpoint */
1695 atomic_set(&kgdb_setting_breakpoint
, 0);
1697 EXPORT_SYMBOL_GPL(kgdb_breakpoint
);
1699 static int __init
opt_kgdb_wait(char *str
)
1701 kgdb_break_asap
= 1;
1703 if (kgdb_io_module_registered
)
1704 kgdb_initial_breakpoint();
1709 early_param("kgdbwait", opt_kgdb_wait
);