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)
204 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
205 * @regs: Current &struct pt_regs.
207 * This function will be called if the particular architecture must
208 * disable hardware debugging while it is processing gdb packets or
209 * handling exception.
211 void __weak
kgdb_disable_hw_debug(struct pt_regs
*regs
)
216 * GDB remote protocol parser:
219 static const char hexchars
[] = "0123456789abcdef";
221 static int hex(char ch
)
223 if ((ch
>= 'a') && (ch
<= 'f'))
224 return ch
- 'a' + 10;
225 if ((ch
>= '0') && (ch
<= '9'))
227 if ((ch
>= 'A') && (ch
<= 'F'))
228 return ch
- 'A' + 10;
232 /* scan for the sequence $<data>#<checksum> */
233 static void get_packet(char *buffer
)
235 unsigned char checksum
;
236 unsigned char xmitcsum
;
242 * Spin and wait around for the start character, ignore all
245 while ((ch
= (kgdb_io_ops
->read_char())) != '$')
255 * now, read until a # or end of buffer is found:
257 while (count
< (BUFMAX
- 1)) {
258 ch
= kgdb_io_ops
->read_char();
261 checksum
= checksum
+ ch
;
268 xmitcsum
= hex(kgdb_io_ops
->read_char()) << 4;
269 xmitcsum
+= hex(kgdb_io_ops
->read_char());
271 if (checksum
!= xmitcsum
)
272 /* failed checksum */
273 kgdb_io_ops
->write_char('-');
275 /* successful transfer */
276 kgdb_io_ops
->write_char('+');
277 if (kgdb_io_ops
->flush
)
278 kgdb_io_ops
->flush();
280 } while (checksum
!= xmitcsum
);
284 * Send the packet in buffer.
285 * Check for gdb connection if asked for.
287 static void put_packet(char *buffer
)
289 unsigned char checksum
;
294 * $<packet info>#<checksum>.
297 kgdb_io_ops
->write_char('$');
301 while ((ch
= buffer
[count
])) {
302 kgdb_io_ops
->write_char(ch
);
307 kgdb_io_ops
->write_char('#');
308 kgdb_io_ops
->write_char(hexchars
[checksum
>> 4]);
309 kgdb_io_ops
->write_char(hexchars
[checksum
& 0xf]);
310 if (kgdb_io_ops
->flush
)
311 kgdb_io_ops
->flush();
313 /* Now see what we get in reply. */
314 ch
= kgdb_io_ops
->read_char();
317 ch
= kgdb_io_ops
->read_char();
319 /* If we get an ACK, we are done. */
324 * If we get the start of another packet, this means
325 * that GDB is attempting to reconnect. We will NAK
326 * the packet being sent, and stop trying to send this
330 kgdb_io_ops
->write_char('-');
331 if (kgdb_io_ops
->flush
)
332 kgdb_io_ops
->flush();
338 static char *pack_hex_byte(char *pkt
, u8 byte
)
340 *pkt
++ = hexchars
[byte
>> 4];
341 *pkt
++ = hexchars
[byte
& 0xf];
347 * Convert the memory pointed to by mem into hex, placing result in buf.
348 * Return a pointer to the last char put in buf (null). May return an error.
350 int kgdb_mem2hex(char *mem
, char *buf
, int count
)
356 * We use the upper half of buf as an intermediate buffer for the
357 * raw memory copy. Hex conversion will work against this one.
361 err
= probe_kernel_read(tmp
, mem
, count
);
364 buf
= pack_hex_byte(buf
, *tmp
);
376 * Copy the binary array pointed to by buf into mem. Fix $, #, and
377 * 0x7d escaped with 0x7d. Return a pointer to the character after
378 * the last byte written.
380 static int kgdb_ebin2mem(char *buf
, char *mem
, int count
)
385 while (count
-- > 0) {
390 err
= probe_kernel_write(mem
, &c
, 1);
401 * Convert the hex array pointed to by buf into binary to be placed in mem.
402 * Return a pointer to the character AFTER the last byte written.
403 * May return an error.
405 int kgdb_hex2mem(char *buf
, char *mem
, int count
)
411 * We use the upper half of buf as an intermediate buffer for the
412 * raw memory that is converted from hex.
414 tmp_raw
= buf
+ count
* 2;
416 tmp_hex
= tmp_raw
- 1;
417 while (tmp_hex
>= buf
) {
419 *tmp_raw
= hex(*tmp_hex
--);
420 *tmp_raw
|= hex(*tmp_hex
--) << 4;
423 return probe_kernel_write(mem
, tmp_raw
, count
);
427 * While we find nice hex chars, build a long_val.
428 * Return number of chars processed.
430 int kgdb_hex2long(char **ptr
, long *long_val
)
438 hex_val
= hex(**ptr
);
442 *long_val
= (*long_val
<< 4) | hex_val
;
450 /* Write memory due to an 'M' or 'X' packet. */
451 static int write_mem_msg(int binary
)
453 char *ptr
= &remcom_in_buffer
[1];
455 unsigned long length
;
458 if (kgdb_hex2long(&ptr
, &addr
) > 0 && *(ptr
++) == ',' &&
459 kgdb_hex2long(&ptr
, &length
) > 0 && *(ptr
++) == ':') {
461 err
= kgdb_ebin2mem(ptr
, (char *)addr
, length
);
463 err
= kgdb_hex2mem(ptr
, (char *)addr
, length
);
466 if (CACHE_FLUSH_IS_SAFE
)
467 flush_icache_range(addr
, addr
+ length
+ 1);
474 static void error_packet(char *pkt
, int error
)
478 pkt
[1] = hexchars
[(error
/ 10)];
479 pkt
[2] = hexchars
[(error
% 10)];
484 * Thread ID accessors. We represent a flat TID space to GDB, where
485 * the per CPU idle threads (which under Linux all have PID 0) are
486 * remapped to negative TIDs.
489 #define BUF_THREAD_ID_SIZE 16
491 static char *pack_threadid(char *pkt
, unsigned char *id
)
495 limit
= pkt
+ BUF_THREAD_ID_SIZE
;
497 pkt
= pack_hex_byte(pkt
, *id
++);
502 static void int_to_threadref(unsigned char *id
, int value
)
507 scan
= (unsigned char *)id
;
510 *scan
++ = (value
>> 24) & 0xff;
511 *scan
++ = (value
>> 16) & 0xff;
512 *scan
++ = (value
>> 8) & 0xff;
513 *scan
++ = (value
& 0xff);
516 static struct task_struct
*getthread(struct pt_regs
*regs
, int tid
)
519 * Non-positive TIDs are remapped idle tasks:
522 return idle_task(-tid
);
525 * find_task_by_pid_ns() does not take the tasklist lock anymore
526 * but is nicely RCU locked - hence is a pretty resilient
529 return find_task_by_pid_ns(tid
, &init_pid_ns
);
533 * CPU debug state control:
537 static void kgdb_wait(struct pt_regs
*regs
)
542 local_irq_save(flags
);
543 cpu
= raw_smp_processor_id();
544 kgdb_info
[cpu
].debuggerinfo
= regs
;
545 kgdb_info
[cpu
].task
= current
;
547 * Make sure the above info reaches the primary CPU before
548 * our cpu_in_kgdb[] flag setting does:
551 atomic_set(&cpu_in_kgdb
[cpu
], 1);
554 * The primary CPU must be active to enter here, but this is
555 * guard in case the primary CPU had not been selected if
556 * this was an entry via nmi.
558 while (atomic_read(&kgdb_active
) == -1)
561 /* Wait till primary CPU goes completely into the debugger. */
562 while (!atomic_read(&cpu_in_kgdb
[atomic_read(&kgdb_active
)]))
565 /* Wait till primary CPU is done with debugging */
566 while (atomic_read(&passive_cpu_wait
[cpu
]))
569 kgdb_info
[cpu
].debuggerinfo
= NULL
;
570 kgdb_info
[cpu
].task
= NULL
;
572 /* fix up hardware debug registers on local cpu */
573 if (arch_kgdb_ops
.correct_hw_break
)
574 arch_kgdb_ops
.correct_hw_break();
576 /* Signal the primary CPU that we are done: */
577 atomic_set(&cpu_in_kgdb
[cpu
], 0);
578 clocksource_touch_watchdog();
579 local_irq_restore(flags
);
584 * Some architectures need cache flushes when we set/clear a
587 static void kgdb_flush_swbreak_addr(unsigned long addr
)
589 if (!CACHE_FLUSH_IS_SAFE
)
593 flush_cache_range(current
->mm
->mmap_cache
,
594 addr
, addr
+ BREAK_INSTR_SIZE
);
596 flush_icache_range(addr
, addr
+ BREAK_INSTR_SIZE
);
601 * SW breakpoint management:
603 static int kgdb_activate_sw_breakpoints(void)
609 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
610 if (kgdb_break
[i
].state
!= BP_SET
)
613 addr
= kgdb_break
[i
].bpt_addr
;
614 error
= kgdb_arch_set_breakpoint(addr
,
615 kgdb_break
[i
].saved_instr
);
619 kgdb_flush_swbreak_addr(addr
);
620 kgdb_break
[i
].state
= BP_ACTIVE
;
625 static int kgdb_set_sw_break(unsigned long addr
)
627 int err
= kgdb_validate_break_address(addr
);
634 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
635 if ((kgdb_break
[i
].state
== BP_SET
) &&
636 (kgdb_break
[i
].bpt_addr
== addr
))
639 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
640 if (kgdb_break
[i
].state
== BP_REMOVED
&&
641 kgdb_break
[i
].bpt_addr
== addr
) {
648 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
649 if (kgdb_break
[i
].state
== BP_UNDEFINED
) {
659 kgdb_break
[breakno
].state
= BP_SET
;
660 kgdb_break
[breakno
].type
= BP_BREAKPOINT
;
661 kgdb_break
[breakno
].bpt_addr
= addr
;
666 static int kgdb_deactivate_sw_breakpoints(void)
672 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
673 if (kgdb_break
[i
].state
!= BP_ACTIVE
)
675 addr
= kgdb_break
[i
].bpt_addr
;
676 error
= kgdb_arch_remove_breakpoint(addr
,
677 kgdb_break
[i
].saved_instr
);
681 kgdb_flush_swbreak_addr(addr
);
682 kgdb_break
[i
].state
= BP_SET
;
687 static int kgdb_remove_sw_break(unsigned long addr
)
691 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
692 if ((kgdb_break
[i
].state
== BP_SET
) &&
693 (kgdb_break
[i
].bpt_addr
== addr
)) {
694 kgdb_break
[i
].state
= BP_REMOVED
;
701 int kgdb_isremovedbreak(unsigned long addr
)
705 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
706 if ((kgdb_break
[i
].state
== BP_REMOVED
) &&
707 (kgdb_break
[i
].bpt_addr
== addr
))
713 int remove_all_break(void)
719 /* Clear memory breakpoints. */
720 for (i
= 0; i
< KGDB_MAX_BREAKPOINTS
; i
++) {
721 if (kgdb_break
[i
].state
!= BP_SET
)
723 addr
= kgdb_break
[i
].bpt_addr
;
724 error
= kgdb_arch_remove_breakpoint(addr
,
725 kgdb_break
[i
].saved_instr
);
728 kgdb_break
[i
].state
= BP_REMOVED
;
731 /* Clear hardware breakpoints. */
732 if (arch_kgdb_ops
.remove_all_hw_break
)
733 arch_kgdb_ops
.remove_all_hw_break();
739 * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs:
741 static inline int shadow_pid(int realpid
)
746 return -1-raw_smp_processor_id();
749 static char gdbmsgbuf
[BUFMAX
+ 1];
751 static void kgdb_msg_write(const char *s
, int len
)
760 /* Fill and send buffers... */
762 bufptr
= gdbmsgbuf
+ 1;
764 /* Calculate how many this time */
765 if ((len
<< 1) > (BUFMAX
- 2))
766 wcount
= (BUFMAX
- 2) >> 1;
770 /* Pack in hex chars */
771 for (i
= 0; i
< wcount
; i
++)
772 bufptr
= pack_hex_byte(bufptr
, s
[i
]);
780 put_packet(gdbmsgbuf
);
785 * Return true if there is a valid kgdb I/O module. Also if no
786 * debugger is attached a message can be printed to the console about
787 * waiting for the debugger to attach.
789 * The print_wait argument is only to be true when called from inside
790 * the core kgdb_handle_exception, because it will wait for the
791 * debugger to attach.
793 static int kgdb_io_ready(int print_wait
)
799 if (atomic_read(&kgdb_setting_breakpoint
))
802 printk(KERN_CRIT
"KGDB: Waiting for remote debugger\n");
807 * All the functions that start with gdb_cmd are the various
808 * operations to implement the handlers for the gdbserial protocol
809 * where KGDB is communicating with an external debugger
812 /* Handle the '?' status packets */
813 static void gdb_cmd_status(struct kgdb_state
*ks
)
816 * We know that this packet is only sent
817 * during initial connect. So to be safe,
818 * we clear out our breakpoints now in case
819 * GDB is reconnecting.
823 remcom_out_buffer
[0] = 'S';
824 pack_hex_byte(&remcom_out_buffer
[1], ks
->signo
);
827 /* Handle the 'g' get registers request */
828 static void gdb_cmd_getregs(struct kgdb_state
*ks
)
830 struct task_struct
*thread
;
831 void *local_debuggerinfo
;
834 thread
= kgdb_usethread
;
836 thread
= kgdb_info
[ks
->cpu
].task
;
837 local_debuggerinfo
= kgdb_info
[ks
->cpu
].debuggerinfo
;
839 local_debuggerinfo
= NULL
;
840 for (i
= 0; i
< NR_CPUS
; i
++) {
842 * Try to find the task on some other
843 * or possibly this node if we do not
844 * find the matching task then we try
845 * to approximate the results.
847 if (thread
== kgdb_info
[i
].task
)
848 local_debuggerinfo
= kgdb_info
[i
].debuggerinfo
;
853 * All threads that don't have debuggerinfo should be
854 * in __schedule() sleeping, since all other CPUs
855 * are in kgdb_wait, and thus have debuggerinfo.
857 if (local_debuggerinfo
) {
858 pt_regs_to_gdb_regs(gdb_regs
, local_debuggerinfo
);
861 * Pull stuff saved during switch_to; nothing
862 * else is accessible (or even particularly
865 * This should be enough for a stack trace.
867 sleeping_thread_to_gdb_regs(gdb_regs
, thread
);
869 kgdb_mem2hex((char *)gdb_regs
, remcom_out_buffer
, NUMREGBYTES
);
872 /* Handle the 'G' set registers request */
873 static void gdb_cmd_setregs(struct kgdb_state
*ks
)
875 kgdb_hex2mem(&remcom_in_buffer
[1], (char *)gdb_regs
, NUMREGBYTES
);
877 if (kgdb_usethread
&& kgdb_usethread
!= current
) {
878 error_packet(remcom_out_buffer
, -EINVAL
);
880 gdb_regs_to_pt_regs(gdb_regs
, ks
->linux_regs
);
881 strcpy(remcom_out_buffer
, "OK");
885 /* Handle the 'm' memory read bytes */
886 static void gdb_cmd_memread(struct kgdb_state
*ks
)
888 char *ptr
= &remcom_in_buffer
[1];
889 unsigned long length
;
893 if (kgdb_hex2long(&ptr
, &addr
) > 0 && *ptr
++ == ',' &&
894 kgdb_hex2long(&ptr
, &length
) > 0) {
895 err
= kgdb_mem2hex((char *)addr
, remcom_out_buffer
, length
);
897 error_packet(remcom_out_buffer
, err
);
899 error_packet(remcom_out_buffer
, -EINVAL
);
903 /* Handle the 'M' memory write bytes */
904 static void gdb_cmd_memwrite(struct kgdb_state
*ks
)
906 int err
= write_mem_msg(0);
909 error_packet(remcom_out_buffer
, err
);
911 strcpy(remcom_out_buffer
, "OK");
914 /* Handle the 'X' memory binary write bytes */
915 static void gdb_cmd_binwrite(struct kgdb_state
*ks
)
917 int err
= write_mem_msg(1);
920 error_packet(remcom_out_buffer
, err
);
922 strcpy(remcom_out_buffer
, "OK");
925 /* Handle the 'D' or 'k', detach or kill packets */
926 static void gdb_cmd_detachkill(struct kgdb_state
*ks
)
930 /* The detach case */
931 if (remcom_in_buffer
[0] == 'D') {
932 error
= remove_all_break();
934 error_packet(remcom_out_buffer
, error
);
936 strcpy(remcom_out_buffer
, "OK");
939 put_packet(remcom_out_buffer
);
942 * Assume the kill case, with no exit code checking,
943 * trying to force detach the debugger:
950 /* Handle the 'R' reboot packets */
951 static int gdb_cmd_reboot(struct kgdb_state
*ks
)
953 /* For now, only honor R0 */
954 if (strcmp(remcom_in_buffer
, "R0") == 0) {
955 printk(KERN_CRIT
"Executing emergency reboot\n");
956 strcpy(remcom_out_buffer
, "OK");
957 put_packet(remcom_out_buffer
);
960 * Execution should not return from
961 * machine_emergency_restart()
963 machine_emergency_restart();
971 /* Handle the 'q' query packets */
972 static void gdb_cmd_query(struct kgdb_state
*ks
)
974 struct task_struct
*thread
;
975 unsigned char thref
[8];
979 switch (remcom_in_buffer
[1]) {
982 if (memcmp(remcom_in_buffer
+ 2, "ThreadInfo", 10)) {
983 error_packet(remcom_out_buffer
, -EINVAL
);
987 if (remcom_in_buffer
[1] == 'f')
990 remcom_out_buffer
[0] = 'm';
991 ptr
= remcom_out_buffer
+ 1;
993 for (i
= 0; i
< 17; ks
->threadid
++) {
994 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
996 int_to_threadref(thref
, ks
->threadid
);
997 pack_threadid(ptr
, thref
);
998 ptr
+= BUF_THREAD_ID_SIZE
;
1007 /* Current thread id */
1008 strcpy(remcom_out_buffer
, "QC");
1009 ks
->threadid
= shadow_pid(current
->pid
);
1010 int_to_threadref(thref
, ks
->threadid
);
1011 pack_threadid(remcom_out_buffer
+ 2, thref
);
1014 if (memcmp(remcom_in_buffer
+ 1, "ThreadExtraInfo,", 16)) {
1015 error_packet(remcom_out_buffer
, -EINVAL
);
1019 ptr
= remcom_in_buffer
+ 17;
1020 kgdb_hex2long(&ptr
, &ks
->threadid
);
1021 if (!getthread(ks
->linux_regs
, ks
->threadid
)) {
1022 error_packet(remcom_out_buffer
, -EINVAL
);
1025 if (ks
->threadid
> 0) {
1026 kgdb_mem2hex(getthread(ks
->linux_regs
,
1027 ks
->threadid
)->comm
,
1028 remcom_out_buffer
, 16);
1030 static char tmpstr
[23 + BUF_THREAD_ID_SIZE
];
1032 sprintf(tmpstr
, "Shadow task %d for pid 0",
1033 (int)(-ks
->threadid
-1));
1034 kgdb_mem2hex(tmpstr
, remcom_out_buffer
, strlen(tmpstr
));
1040 /* Handle the 'H' task query packets */
1041 static void gdb_cmd_task(struct kgdb_state
*ks
)
1043 struct task_struct
*thread
;
1046 switch (remcom_in_buffer
[1]) {
1048 ptr
= &remcom_in_buffer
[2];
1049 kgdb_hex2long(&ptr
, &ks
->threadid
);
1050 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
1051 if (!thread
&& ks
->threadid
> 0) {
1052 error_packet(remcom_out_buffer
, -EINVAL
);
1055 kgdb_usethread
= thread
;
1056 ks
->kgdb_usethreadid
= ks
->threadid
;
1057 strcpy(remcom_out_buffer
, "OK");
1060 ptr
= &remcom_in_buffer
[2];
1061 kgdb_hex2long(&ptr
, &ks
->threadid
);
1062 if (!ks
->threadid
) {
1063 kgdb_contthread
= NULL
;
1065 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
1066 if (!thread
&& ks
->threadid
> 0) {
1067 error_packet(remcom_out_buffer
, -EINVAL
);
1070 kgdb_contthread
= thread
;
1072 strcpy(remcom_out_buffer
, "OK");
1077 /* Handle the 'T' thread query packets */
1078 static void gdb_cmd_thread(struct kgdb_state
*ks
)
1080 char *ptr
= &remcom_in_buffer
[1];
1081 struct task_struct
*thread
;
1083 kgdb_hex2long(&ptr
, &ks
->threadid
);
1084 thread
= getthread(ks
->linux_regs
, ks
->threadid
);
1086 strcpy(remcom_out_buffer
, "OK");
1088 error_packet(remcom_out_buffer
, -EINVAL
);
1091 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
1092 static void gdb_cmd_break(struct kgdb_state
*ks
)
1095 * Since GDB-5.3, it's been drafted that '0' is a software
1096 * breakpoint, '1' is a hardware breakpoint, so let's do that.
1098 char *bpt_type
= &remcom_in_buffer
[1];
1099 char *ptr
= &remcom_in_buffer
[2];
1101 unsigned long length
;
1104 if (arch_kgdb_ops
.set_hw_breakpoint
&& *bpt_type
>= '1') {
1106 if (*bpt_type
> '4')
1109 if (*bpt_type
!= '0' && *bpt_type
!= '1')
1115 * Test if this is a hardware breakpoint, and
1118 if (*bpt_type
== '1' && !(arch_kgdb_ops
.flags
& KGDB_HW_BREAKPOINT
))
1122 if (*(ptr
++) != ',') {
1123 error_packet(remcom_out_buffer
, -EINVAL
);
1126 if (!kgdb_hex2long(&ptr
, &addr
)) {
1127 error_packet(remcom_out_buffer
, -EINVAL
);
1130 if (*(ptr
++) != ',' ||
1131 !kgdb_hex2long(&ptr
, &length
)) {
1132 error_packet(remcom_out_buffer
, -EINVAL
);
1136 if (remcom_in_buffer
[0] == 'Z' && *bpt_type
== '0')
1137 error
= kgdb_set_sw_break(addr
);
1138 else if (remcom_in_buffer
[0] == 'z' && *bpt_type
== '0')
1139 error
= kgdb_remove_sw_break(addr
);
1140 else if (remcom_in_buffer
[0] == 'Z')
1141 error
= arch_kgdb_ops
.set_hw_breakpoint(addr
,
1142 (int)length
, *bpt_type
- '0');
1143 else if (remcom_in_buffer
[0] == 'z')
1144 error
= arch_kgdb_ops
.remove_hw_breakpoint(addr
,
1145 (int) length
, *bpt_type
- '0');
1148 strcpy(remcom_out_buffer
, "OK");
1150 error_packet(remcom_out_buffer
, error
);
1153 /* Handle the 'C' signal / exception passing packets */
1154 static int gdb_cmd_exception_pass(struct kgdb_state
*ks
)
1156 /* C09 == pass exception
1157 * C15 == detach kgdb, pass exception
1159 if (remcom_in_buffer
[1] == '0' && remcom_in_buffer
[2] == '9') {
1161 ks
->pass_exception
= 1;
1162 remcom_in_buffer
[0] = 'c';
1164 } else if (remcom_in_buffer
[1] == '1' && remcom_in_buffer
[2] == '5') {
1166 ks
->pass_exception
= 1;
1167 remcom_in_buffer
[0] = 'D';
1173 error_packet(remcom_out_buffer
, -EINVAL
);
1177 /* Indicate fall through */
1182 * This function performs all gdbserial command procesing
1184 static int gdb_serial_stub(struct kgdb_state
*ks
)
1189 /* Clear the out buffer. */
1190 memset(remcom_out_buffer
, 0, sizeof(remcom_out_buffer
));
1192 if (kgdb_connected
) {
1193 unsigned char thref
[8];
1196 /* Reply to host that an exception has occurred */
1197 ptr
= remcom_out_buffer
;
1199 ptr
= pack_hex_byte(ptr
, ks
->signo
);
1200 ptr
+= strlen(strcpy(ptr
, "thread:"));
1201 int_to_threadref(thref
, shadow_pid(current
->pid
));
1202 ptr
= pack_threadid(ptr
, thref
);
1204 put_packet(remcom_out_buffer
);
1207 kgdb_usethread
= kgdb_info
[ks
->cpu
].task
;
1208 ks
->kgdb_usethreadid
= shadow_pid(kgdb_info
[ks
->cpu
].task
->pid
);
1209 ks
->pass_exception
= 0;
1214 /* Clear the out buffer. */
1215 memset(remcom_out_buffer
, 0, sizeof(remcom_out_buffer
));
1217 get_packet(remcom_in_buffer
);
1219 switch (remcom_in_buffer
[0]) {
1220 case '?': /* gdbserial status */
1223 case 'g': /* return the value of the CPU registers */
1224 gdb_cmd_getregs(ks
);
1226 case 'G': /* set the value of the CPU registers - return OK */
1227 gdb_cmd_setregs(ks
);
1229 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
1230 gdb_cmd_memread(ks
);
1232 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1233 gdb_cmd_memwrite(ks
);
1235 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1236 gdb_cmd_binwrite(ks
);
1238 /* kill or detach. KGDB should treat this like a
1241 case 'D': /* Debugger detach */
1242 case 'k': /* Debugger detach via kill */
1243 gdb_cmd_detachkill(ks
);
1244 goto default_handle
;
1245 case 'R': /* Reboot */
1246 if (gdb_cmd_reboot(ks
))
1247 goto default_handle
;
1249 case 'q': /* query command */
1252 case 'H': /* task related */
1255 case 'T': /* Query thread status */
1258 case 'z': /* Break point remove */
1259 case 'Z': /* Break point set */
1262 case 'C': /* Exception passing */
1263 tmp
= gdb_cmd_exception_pass(ks
);
1265 goto default_handle
;
1268 /* Fall through on tmp < 0 */
1269 case 'c': /* Continue packet */
1270 case 's': /* Single step packet */
1271 if (kgdb_contthread
&& kgdb_contthread
!= current
) {
1272 /* Can't switch threads in kgdb */
1273 error_packet(remcom_out_buffer
, -EINVAL
);
1276 kgdb_activate_sw_breakpoints();
1277 /* Fall through to default processing */
1280 error
= kgdb_arch_handle_exception(ks
->ex_vector
,
1287 * Leave cmd processing on error, detach,
1288 * kill, continue, or single step.
1290 if (error
>= 0 || remcom_in_buffer
[0] == 'D' ||
1291 remcom_in_buffer
[0] == 'k') {
1298 /* reply to the request */
1299 put_packet(remcom_out_buffer
);
1303 if (ks
->pass_exception
)
1308 static int kgdb_reenter_check(struct kgdb_state
*ks
)
1312 if (atomic_read(&kgdb_active
) != raw_smp_processor_id())
1315 /* Panic on recursive debugger calls: */
1317 addr
= kgdb_arch_pc(ks
->ex_vector
, ks
->linux_regs
);
1318 kgdb_deactivate_sw_breakpoints();
1321 * If the break point removed ok at the place exception
1322 * occurred, try to recover and print a warning to the end
1323 * user because the user planted a breakpoint in a place that
1324 * KGDB needs in order to function.
1326 if (kgdb_remove_sw_break(addr
) == 0) {
1327 exception_level
= 0;
1328 kgdb_skipexception(ks
->ex_vector
, ks
->linux_regs
);
1329 kgdb_activate_sw_breakpoints();
1330 printk(KERN_CRIT
"KGDB: re-enter error: breakpoint removed %lx\n",
1337 kgdb_skipexception(ks
->ex_vector
, ks
->linux_regs
);
1339 if (exception_level
> 1) {
1341 panic("Recursive entry to debugger");
1344 printk(KERN_CRIT
"KGDB: re-enter exception: ALL breakpoints killed\n");
1346 panic("Recursive entry to debugger");
1352 * kgdb_handle_exception() - main entry point from a kernel exception
1354 * Locking hierarchy:
1355 * interface locks, if any (begin_session)
1356 * kgdb lock (kgdb_active)
1359 kgdb_handle_exception(int evector
, int signo
, int ecode
, struct pt_regs
*regs
)
1361 struct kgdb_state kgdb_var
;
1362 struct kgdb_state
*ks
= &kgdb_var
;
1363 unsigned long flags
;
1367 ks
->cpu
= raw_smp_processor_id();
1368 ks
->ex_vector
= evector
;
1370 ks
->ex_vector
= evector
;
1371 ks
->err_code
= ecode
;
1372 ks
->kgdb_usethreadid
= 0;
1373 ks
->linux_regs
= regs
;
1375 if (kgdb_reenter_check(ks
))
1376 return 0; /* Ouch, double exception ! */
1380 * Interrupts will be restored by the 'trap return' code, except when
1383 local_irq_save(flags
);
1385 cpu
= raw_smp_processor_id();
1388 * Acquire the kgdb_active lock:
1390 while (atomic_cmpxchg(&kgdb_active
, -1, cpu
) != -1)
1394 * Do not start the debugger connection on this CPU if the last
1395 * instance of the exception handler wanted to come into the
1396 * debugger on a different CPU via a single step
1398 if (atomic_read(&kgdb_cpu_doing_single_step
) != -1 &&
1399 atomic_read(&kgdb_cpu_doing_single_step
) != cpu
) {
1401 atomic_set(&kgdb_active
, -1);
1402 clocksource_touch_watchdog();
1403 local_irq_restore(flags
);
1408 if (!kgdb_io_ready(1)) {
1410 goto kgdb_restore
; /* No I/O connection, so resume the system */
1414 * Don't enter if we have hit a removed breakpoint.
1416 if (kgdb_skipexception(ks
->ex_vector
, ks
->linux_regs
))
1419 /* Call the I/O driver's pre_exception routine */
1420 if (kgdb_io_ops
->pre_exception
)
1421 kgdb_io_ops
->pre_exception();
1423 kgdb_info
[ks
->cpu
].debuggerinfo
= ks
->linux_regs
;
1424 kgdb_info
[ks
->cpu
].task
= current
;
1426 kgdb_disable_hw_debug(ks
->linux_regs
);
1429 * Get the passive CPU lock which will hold all the non-primary
1430 * CPU in a spin state while the debugger is active
1432 if (!kgdb_single_step
|| !kgdb_contthread
) {
1433 for (i
= 0; i
< NR_CPUS
; i
++)
1434 atomic_set(&passive_cpu_wait
[i
], 1);
1438 /* Signal the other CPUs to enter kgdb_wait() */
1439 if ((!kgdb_single_step
|| !kgdb_contthread
) && kgdb_do_roundup
)
1440 kgdb_roundup_cpus(flags
);
1444 * spin_lock code is good enough as a barrier so we don't
1447 atomic_set(&cpu_in_kgdb
[ks
->cpu
], 1);
1450 * Wait for the other CPUs to be notified and be waiting for us:
1452 for_each_online_cpu(i
) {
1453 while (!atomic_read(&cpu_in_kgdb
[i
]))
1458 * At this point the primary processor is completely
1459 * in the debugger and all secondary CPUs are quiescent
1461 kgdb_post_primary_code(ks
->linux_regs
, ks
->ex_vector
, ks
->err_code
);
1462 kgdb_deactivate_sw_breakpoints();
1463 kgdb_single_step
= 0;
1464 kgdb_contthread
= NULL
;
1465 exception_level
= 0;
1467 /* Talk to debugger with gdbserial protocol */
1468 error
= gdb_serial_stub(ks
);
1470 /* Call the I/O driver's post_exception routine */
1471 if (kgdb_io_ops
->post_exception
)
1472 kgdb_io_ops
->post_exception();
1474 kgdb_info
[ks
->cpu
].debuggerinfo
= NULL
;
1475 kgdb_info
[ks
->cpu
].task
= NULL
;
1476 atomic_set(&cpu_in_kgdb
[ks
->cpu
], 0);
1478 if (!kgdb_single_step
|| !kgdb_contthread
) {
1479 for (i
= NR_CPUS
-1; i
>= 0; i
--)
1480 atomic_set(&passive_cpu_wait
[i
], 0);
1482 * Wait till all the CPUs have quit
1483 * from the debugger.
1485 for_each_online_cpu(i
) {
1486 while (atomic_read(&cpu_in_kgdb
[i
]))
1492 /* Free kgdb_active */
1493 atomic_set(&kgdb_active
, -1);
1494 clocksource_touch_watchdog();
1495 local_irq_restore(flags
);
1500 int kgdb_nmicallback(int cpu
, void *regs
)
1503 if (!atomic_read(&cpu_in_kgdb
[cpu
]) &&
1504 atomic_read(&kgdb_active
) != cpu
) {
1505 kgdb_wait((struct pt_regs
*)regs
);
1512 void kgdb_console_write(struct console
*co
, const char *s
, unsigned count
)
1514 unsigned long flags
;
1516 /* If we're debugging, or KGDB has not connected, don't try
1518 if (!kgdb_connected
|| atomic_read(&kgdb_active
) != -1)
1521 local_irq_save(flags
);
1522 kgdb_msg_write(s
, count
);
1523 local_irq_restore(flags
);
1526 static struct console kgdbcons
= {
1528 .write
= kgdb_console_write
,
1529 .flags
= CON_PRINTBUFFER
| CON_ENABLED
,
1533 #ifdef CONFIG_MAGIC_SYSRQ
1534 static void sysrq_handle_gdb(int key
, struct tty_struct
*tty
)
1537 printk(KERN_CRIT
"ERROR: No KGDB I/O module available\n");
1540 if (!kgdb_connected
)
1541 printk(KERN_CRIT
"Entering KGDB\n");
1546 static struct sysrq_key_op sysrq_gdb_op
= {
1547 .handler
= sysrq_handle_gdb
,
1549 .action_msg
= "GDB",
1553 static void kgdb_register_callbacks(void)
1555 if (!kgdb_io_module_registered
) {
1556 kgdb_io_module_registered
= 1;
1558 #ifdef CONFIG_MAGIC_SYSRQ
1559 register_sysrq_key('g', &sysrq_gdb_op
);
1561 if (kgdb_use_con
&& !kgdb_con_registered
) {
1562 register_console(&kgdbcons
);
1563 kgdb_con_registered
= 1;
1568 static void kgdb_unregister_callbacks(void)
1571 * When this routine is called KGDB should unregister from the
1572 * panic handler and clean up, making sure it is not handling any
1573 * break exceptions at the time.
1575 if (kgdb_io_module_registered
) {
1576 kgdb_io_module_registered
= 0;
1578 #ifdef CONFIG_MAGIC_SYSRQ
1579 unregister_sysrq_key('g', &sysrq_gdb_op
);
1581 if (kgdb_con_registered
) {
1582 unregister_console(&kgdbcons
);
1583 kgdb_con_registered
= 0;
1588 static void kgdb_initial_breakpoint(void)
1590 kgdb_break_asap
= 0;
1592 printk(KERN_CRIT
"kgdb: Waiting for connection from remote gdb...\n");
1597 * kkgdb_register_io_module - register KGDB IO module
1598 * @new_kgdb_io_ops: the io ops vector
1600 * Register it with the KGDB core.
1602 int kgdb_register_io_module(struct kgdb_io
*new_kgdb_io_ops
)
1606 spin_lock(&kgdb_registration_lock
);
1609 spin_unlock(&kgdb_registration_lock
);
1611 printk(KERN_ERR
"kgdb: Another I/O driver is already "
1612 "registered with KGDB.\n");
1616 if (new_kgdb_io_ops
->init
) {
1617 err
= new_kgdb_io_ops
->init();
1619 spin_unlock(&kgdb_registration_lock
);
1624 kgdb_io_ops
= new_kgdb_io_ops
;
1626 spin_unlock(&kgdb_registration_lock
);
1628 printk(KERN_INFO
"kgdb: Registered I/O driver %s.\n",
1629 new_kgdb_io_ops
->name
);
1632 kgdb_register_callbacks();
1634 if (kgdb_break_asap
)
1635 kgdb_initial_breakpoint();
1639 EXPORT_SYMBOL_GPL(kgdb_register_io_module
);
1642 * kkgdb_unregister_io_module - unregister KGDB IO module
1643 * @old_kgdb_io_ops: the io ops vector
1645 * Unregister it with the KGDB core.
1647 void kgdb_unregister_io_module(struct kgdb_io
*old_kgdb_io_ops
)
1649 BUG_ON(kgdb_connected
);
1652 * KGDB is no longer able to communicate out, so
1653 * unregister our callbacks and reset state.
1655 kgdb_unregister_callbacks();
1657 spin_lock(&kgdb_registration_lock
);
1659 WARN_ON_ONCE(kgdb_io_ops
!= old_kgdb_io_ops
);
1662 spin_unlock(&kgdb_registration_lock
);
1665 "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
1666 old_kgdb_io_ops
->name
);
1668 EXPORT_SYMBOL_GPL(kgdb_unregister_io_module
);
1671 * kgdb_breakpoint - generate breakpoint exception
1673 * This function will generate a breakpoint exception. It is used at the
1674 * beginning of a program to sync up with a debugger and can be used
1675 * otherwise as a quick means to stop program execution and "break" into
1678 void kgdb_breakpoint(void)
1680 atomic_set(&kgdb_setting_breakpoint
, 1);
1681 wmb(); /* Sync point before breakpoint */
1682 arch_kgdb_breakpoint();
1683 wmb(); /* Sync point after breakpoint */
1684 atomic_set(&kgdb_setting_breakpoint
, 0);
1686 EXPORT_SYMBOL_GPL(kgdb_breakpoint
);
1688 static int __init
opt_kgdb_wait(char *str
)
1690 kgdb_break_asap
= 1;
1692 if (kgdb_io_module_registered
)
1693 kgdb_initial_breakpoint();
1698 early_param("kgdbwait", opt_kgdb_wait
);