xref: /linux/kernel/debug/kdb/kdb_main.c (revision bbcd53c960713507ae764bf81970651b5577b95a)
1 /*
2  * Kernel Debugger Architecture Independent Main Code
3  *
4  * This file is subject to the terms and conditions of the GNU General Public
5  * License.  See the file "COPYING" in the main directory of this archive
6  * for more details.
7  *
8  * Copyright (C) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
9  * Copyright (C) 2000 Stephane Eranian <eranian@hpl.hp.com>
10  * Xscale (R) modifications copyright (C) 2003 Intel Corporation.
11  * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
12  */
13 
14 #include <linux/ctype.h>
15 #include <linux/types.h>
16 #include <linux/string.h>
17 #include <linux/kernel.h>
18 #include <linux/kmsg_dump.h>
19 #include <linux/reboot.h>
20 #include <linux/sched.h>
21 #include <linux/sched/loadavg.h>
22 #include <linux/sched/stat.h>
23 #include <linux/sched/debug.h>
24 #include <linux/sysrq.h>
25 #include <linux/smp.h>
26 #include <linux/utsname.h>
27 #include <linux/vmalloc.h>
28 #include <linux/atomic.h>
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/mm.h>
32 #include <linux/init.h>
33 #include <linux/kallsyms.h>
34 #include <linux/kgdb.h>
35 #include <linux/kdb.h>
36 #include <linux/list.h>
37 #include <linux/notifier.h>
38 #include <linux/interrupt.h>
39 #include <linux/delay.h>
40 #include <linux/nmi.h>
41 #include <linux/time.h>
42 #include <linux/ptrace.h>
43 #include <linux/sysctl.h>
44 #include <linux/cpu.h>
45 #include <linux/kdebug.h>
46 #include <linux/proc_fs.h>
47 #include <linux/uaccess.h>
48 #include <linux/slab.h>
49 #include "kdb_private.h"
50 
51 #undef	MODULE_PARAM_PREFIX
52 #define	MODULE_PARAM_PREFIX "kdb."
53 
54 static int kdb_cmd_enabled = CONFIG_KDB_DEFAULT_ENABLE;
55 module_param_named(cmd_enable, kdb_cmd_enabled, int, 0600);
56 
57 char kdb_grep_string[KDB_GREP_STRLEN];
58 int kdb_grepping_flag;
59 EXPORT_SYMBOL(kdb_grepping_flag);
60 int kdb_grep_leading;
61 int kdb_grep_trailing;
62 
63 /*
64  * Kernel debugger state flags
65  */
66 unsigned int kdb_flags;
67 
68 /*
69  * kdb_lock protects updates to kdb_initial_cpu.  Used to
70  * single thread processors through the kernel debugger.
71  */
72 int kdb_initial_cpu = -1;	/* cpu number that owns kdb */
73 int kdb_nextline = 1;
74 int kdb_state;			/* General KDB state */
75 
76 struct task_struct *kdb_current_task;
77 struct pt_regs *kdb_current_regs;
78 
79 const char *kdb_diemsg;
80 static int kdb_go_count;
81 #ifdef CONFIG_KDB_CONTINUE_CATASTROPHIC
82 static unsigned int kdb_continue_catastrophic =
83 	CONFIG_KDB_CONTINUE_CATASTROPHIC;
84 #else
85 static unsigned int kdb_continue_catastrophic;
86 #endif
87 
88 /* kdb_cmds_head describes the available commands. */
89 static LIST_HEAD(kdb_cmds_head);
90 
91 typedef struct _kdbmsg {
92 	int	km_diag;	/* kdb diagnostic */
93 	char	*km_msg;	/* Corresponding message text */
94 } kdbmsg_t;
95 
96 #define KDBMSG(msgnum, text) \
97 	{ KDB_##msgnum, text }
98 
99 static kdbmsg_t kdbmsgs[] = {
100 	KDBMSG(NOTFOUND, "Command Not Found"),
101 	KDBMSG(ARGCOUNT, "Improper argument count, see usage."),
102 	KDBMSG(BADWIDTH, "Illegal value for BYTESPERWORD use 1, 2, 4 or 8, "
103 	       "8 is only allowed on 64 bit systems"),
104 	KDBMSG(BADRADIX, "Illegal value for RADIX use 8, 10 or 16"),
105 	KDBMSG(NOTENV, "Cannot find environment variable"),
106 	KDBMSG(NOENVVALUE, "Environment variable should have value"),
107 	KDBMSG(NOTIMP, "Command not implemented"),
108 	KDBMSG(ENVFULL, "Environment full"),
109 	KDBMSG(ENVBUFFULL, "Environment buffer full"),
110 	KDBMSG(TOOMANYBPT, "Too many breakpoints defined"),
111 #ifdef CONFIG_CPU_XSCALE
112 	KDBMSG(TOOMANYDBREGS, "More breakpoints than ibcr registers defined"),
113 #else
114 	KDBMSG(TOOMANYDBREGS, "More breakpoints than db registers defined"),
115 #endif
116 	KDBMSG(DUPBPT, "Duplicate breakpoint address"),
117 	KDBMSG(BPTNOTFOUND, "Breakpoint not found"),
118 	KDBMSG(BADMODE, "Invalid IDMODE"),
119 	KDBMSG(BADINT, "Illegal numeric value"),
120 	KDBMSG(INVADDRFMT, "Invalid symbolic address format"),
121 	KDBMSG(BADREG, "Invalid register name"),
122 	KDBMSG(BADCPUNUM, "Invalid cpu number"),
123 	KDBMSG(BADLENGTH, "Invalid length field"),
124 	KDBMSG(NOBP, "No Breakpoint exists"),
125 	KDBMSG(BADADDR, "Invalid address"),
126 	KDBMSG(NOPERM, "Permission denied"),
127 };
128 #undef KDBMSG
129 
130 static const int __nkdb_err = ARRAY_SIZE(kdbmsgs);
131 
132 
133 /*
134  * Initial environment.   This is all kept static and local to
135  * this file.   We don't want to rely on the memory allocation
136  * mechanisms in the kernel, so we use a very limited allocate-only
137  * heap for new and altered environment variables.  The entire
138  * environment is limited to a fixed number of entries (add more
139  * to __env[] if required) and a fixed amount of heap (add more to
140  * KDB_ENVBUFSIZE if required).
141  */
142 
143 static char *__env[31] = {
144 #if defined(CONFIG_SMP)
145 	"PROMPT=[%d]kdb> ",
146 #else
147 	"PROMPT=kdb> ",
148 #endif
149 	"MOREPROMPT=more> ",
150 	"RADIX=16",
151 	"MDCOUNT=8",		/* lines of md output */
152 	KDB_PLATFORM_ENV,
153 	"DTABCOUNT=30",
154 	"NOSECT=1",
155 };
156 
157 static const int __nenv = ARRAY_SIZE(__env);
158 
159 struct task_struct *kdb_curr_task(int cpu)
160 {
161 	struct task_struct *p = curr_task(cpu);
162 #ifdef	_TIF_MCA_INIT
163 	if ((task_thread_info(p)->flags & _TIF_MCA_INIT) && KDB_TSK(cpu))
164 		p = krp->p;
165 #endif
166 	return p;
167 }
168 
169 /*
170  * Check whether the flags of the current command and the permissions
171  * of the kdb console has allow a command to be run.
172  */
173 static inline bool kdb_check_flags(kdb_cmdflags_t flags, int permissions,
174 				   bool no_args)
175 {
176 	/* permissions comes from userspace so needs massaging slightly */
177 	permissions &= KDB_ENABLE_MASK;
178 	permissions |= KDB_ENABLE_ALWAYS_SAFE;
179 
180 	/* some commands change group when launched with no arguments */
181 	if (no_args)
182 		permissions |= permissions << KDB_ENABLE_NO_ARGS_SHIFT;
183 
184 	flags |= KDB_ENABLE_ALL;
185 
186 	return permissions & flags;
187 }
188 
189 /*
190  * kdbgetenv - This function will return the character string value of
191  *	an environment variable.
192  * Parameters:
193  *	match	A character string representing an environment variable.
194  * Returns:
195  *	NULL	No environment variable matches 'match'
196  *	char*	Pointer to string value of environment variable.
197  */
198 char *kdbgetenv(const char *match)
199 {
200 	char **ep = __env;
201 	int matchlen = strlen(match);
202 	int i;
203 
204 	for (i = 0; i < __nenv; i++) {
205 		char *e = *ep++;
206 
207 		if (!e)
208 			continue;
209 
210 		if ((strncmp(match, e, matchlen) == 0)
211 		 && ((e[matchlen] == '\0')
212 		   || (e[matchlen] == '='))) {
213 			char *cp = strchr(e, '=');
214 			return cp ? ++cp : "";
215 		}
216 	}
217 	return NULL;
218 }
219 
220 /*
221  * kdballocenv - This function is used to allocate bytes for
222  *	environment entries.
223  * Parameters:
224  *	match	A character string representing a numeric value
225  * Outputs:
226  *	*value  the unsigned long representation of the env variable 'match'
227  * Returns:
228  *	Zero on success, a kdb diagnostic on failure.
229  * Remarks:
230  *	We use a static environment buffer (envbuffer) to hold the values
231  *	of dynamically generated environment variables (see kdb_set).  Buffer
232  *	space once allocated is never free'd, so over time, the amount of space
233  *	(currently 512 bytes) will be exhausted if env variables are changed
234  *	frequently.
235  */
236 static char *kdballocenv(size_t bytes)
237 {
238 #define	KDB_ENVBUFSIZE	512
239 	static char envbuffer[KDB_ENVBUFSIZE];
240 	static int envbufsize;
241 	char *ep = NULL;
242 
243 	if ((KDB_ENVBUFSIZE - envbufsize) >= bytes) {
244 		ep = &envbuffer[envbufsize];
245 		envbufsize += bytes;
246 	}
247 	return ep;
248 }
249 
250 /*
251  * kdbgetulenv - This function will return the value of an unsigned
252  *	long-valued environment variable.
253  * Parameters:
254  *	match	A character string representing a numeric value
255  * Outputs:
256  *	*value  the unsigned long represntation of the env variable 'match'
257  * Returns:
258  *	Zero on success, a kdb diagnostic on failure.
259  */
260 static int kdbgetulenv(const char *match, unsigned long *value)
261 {
262 	char *ep;
263 
264 	ep = kdbgetenv(match);
265 	if (!ep)
266 		return KDB_NOTENV;
267 	if (strlen(ep) == 0)
268 		return KDB_NOENVVALUE;
269 
270 	*value = simple_strtoul(ep, NULL, 0);
271 
272 	return 0;
273 }
274 
275 /*
276  * kdbgetintenv - This function will return the value of an
277  *	integer-valued environment variable.
278  * Parameters:
279  *	match	A character string representing an integer-valued env variable
280  * Outputs:
281  *	*value  the integer representation of the environment variable 'match'
282  * Returns:
283  *	Zero on success, a kdb diagnostic on failure.
284  */
285 int kdbgetintenv(const char *match, int *value)
286 {
287 	unsigned long val;
288 	int diag;
289 
290 	diag = kdbgetulenv(match, &val);
291 	if (!diag)
292 		*value = (int) val;
293 	return diag;
294 }
295 
296 /*
297  * kdb_setenv() - Alter an existing environment variable or create a new one.
298  * @var: Name of the variable
299  * @val: Value of the variable
300  *
301  * Return: Zero on success, a kdb diagnostic on failure.
302  */
303 static int kdb_setenv(const char *var, const char *val)
304 {
305 	int i;
306 	char *ep;
307 	size_t varlen, vallen;
308 
309 	varlen = strlen(var);
310 	vallen = strlen(val);
311 	ep = kdballocenv(varlen + vallen + 2);
312 	if (ep == (char *)0)
313 		return KDB_ENVBUFFULL;
314 
315 	sprintf(ep, "%s=%s", var, val);
316 
317 	for (i = 0; i < __nenv; i++) {
318 		if (__env[i]
319 		 && ((strncmp(__env[i], var, varlen) == 0)
320 		   && ((__env[i][varlen] == '\0')
321 		    || (__env[i][varlen] == '=')))) {
322 			__env[i] = ep;
323 			return 0;
324 		}
325 	}
326 
327 	/*
328 	 * Wasn't existing variable.  Fit into slot.
329 	 */
330 	for (i = 0; i < __nenv-1; i++) {
331 		if (__env[i] == (char *)0) {
332 			__env[i] = ep;
333 			return 0;
334 		}
335 	}
336 
337 	return KDB_ENVFULL;
338 }
339 
340 /*
341  * kdb_printenv() - Display the current environment variables.
342  */
343 static void kdb_printenv(void)
344 {
345 	int i;
346 
347 	for (i = 0; i < __nenv; i++) {
348 		if (__env[i])
349 			kdb_printf("%s\n", __env[i]);
350 	}
351 }
352 
353 /*
354  * kdbgetularg - This function will convert a numeric string into an
355  *	unsigned long value.
356  * Parameters:
357  *	arg	A character string representing a numeric value
358  * Outputs:
359  *	*value  the unsigned long represntation of arg.
360  * Returns:
361  *	Zero on success, a kdb diagnostic on failure.
362  */
363 int kdbgetularg(const char *arg, unsigned long *value)
364 {
365 	char *endp;
366 	unsigned long val;
367 
368 	val = simple_strtoul(arg, &endp, 0);
369 
370 	if (endp == arg) {
371 		/*
372 		 * Also try base 16, for us folks too lazy to type the
373 		 * leading 0x...
374 		 */
375 		val = simple_strtoul(arg, &endp, 16);
376 		if (endp == arg)
377 			return KDB_BADINT;
378 	}
379 
380 	*value = val;
381 
382 	return 0;
383 }
384 
385 int kdbgetu64arg(const char *arg, u64 *value)
386 {
387 	char *endp;
388 	u64 val;
389 
390 	val = simple_strtoull(arg, &endp, 0);
391 
392 	if (endp == arg) {
393 
394 		val = simple_strtoull(arg, &endp, 16);
395 		if (endp == arg)
396 			return KDB_BADINT;
397 	}
398 
399 	*value = val;
400 
401 	return 0;
402 }
403 
404 /*
405  * kdb_set - This function implements the 'set' command.  Alter an
406  *	existing environment variable or create a new one.
407  */
408 int kdb_set(int argc, const char **argv)
409 {
410 	/*
411 	 * we can be invoked two ways:
412 	 *   set var=value    argv[1]="var", argv[2]="value"
413 	 *   set var = value  argv[1]="var", argv[2]="=", argv[3]="value"
414 	 * - if the latter, shift 'em down.
415 	 */
416 	if (argc == 3) {
417 		argv[2] = argv[3];
418 		argc--;
419 	}
420 
421 	if (argc != 2)
422 		return KDB_ARGCOUNT;
423 
424 	/*
425 	 * Censor sensitive variables
426 	 */
427 	if (strcmp(argv[1], "PROMPT") == 0 &&
428 	    !kdb_check_flags(KDB_ENABLE_MEM_READ, kdb_cmd_enabled, false))
429 		return KDB_NOPERM;
430 
431 	/*
432 	 * Check for internal variables
433 	 */
434 	if (strcmp(argv[1], "KDBDEBUG") == 0) {
435 		unsigned int debugflags;
436 		char *cp;
437 
438 		debugflags = simple_strtoul(argv[2], &cp, 0);
439 		if (cp == argv[2] || debugflags & ~KDB_DEBUG_FLAG_MASK) {
440 			kdb_printf("kdb: illegal debug flags '%s'\n",
441 				    argv[2]);
442 			return 0;
443 		}
444 		kdb_flags = (kdb_flags & ~KDB_DEBUG(MASK))
445 			| (debugflags << KDB_DEBUG_FLAG_SHIFT);
446 
447 		return 0;
448 	}
449 
450 	/*
451 	 * Tokenizer squashed the '=' sign.  argv[1] is variable
452 	 * name, argv[2] = value.
453 	 */
454 	return kdb_setenv(argv[1], argv[2]);
455 }
456 
457 static int kdb_check_regs(void)
458 {
459 	if (!kdb_current_regs) {
460 		kdb_printf("No current kdb registers."
461 			   "  You may need to select another task\n");
462 		return KDB_BADREG;
463 	}
464 	return 0;
465 }
466 
467 /*
468  * kdbgetaddrarg - This function is responsible for parsing an
469  *	address-expression and returning the value of the expression,
470  *	symbol name, and offset to the caller.
471  *
472  *	The argument may consist of a numeric value (decimal or
473  *	hexidecimal), a symbol name, a register name (preceded by the
474  *	percent sign), an environment variable with a numeric value
475  *	(preceded by a dollar sign) or a simple arithmetic expression
476  *	consisting of a symbol name, +/-, and a numeric constant value
477  *	(offset).
478  * Parameters:
479  *	argc	- count of arguments in argv
480  *	argv	- argument vector
481  *	*nextarg - index to next unparsed argument in argv[]
482  *	regs	- Register state at time of KDB entry
483  * Outputs:
484  *	*value	- receives the value of the address-expression
485  *	*offset - receives the offset specified, if any
486  *	*name   - receives the symbol name, if any
487  *	*nextarg - index to next unparsed argument in argv[]
488  * Returns:
489  *	zero is returned on success, a kdb diagnostic code is
490  *      returned on error.
491  */
492 int kdbgetaddrarg(int argc, const char **argv, int *nextarg,
493 		  unsigned long *value,  long *offset,
494 		  char **name)
495 {
496 	unsigned long addr;
497 	unsigned long off = 0;
498 	int positive;
499 	int diag;
500 	int found = 0;
501 	char *symname;
502 	char symbol = '\0';
503 	char *cp;
504 	kdb_symtab_t symtab;
505 
506 	/*
507 	 * If the enable flags prohibit both arbitrary memory access
508 	 * and flow control then there are no reasonable grounds to
509 	 * provide symbol lookup.
510 	 */
511 	if (!kdb_check_flags(KDB_ENABLE_MEM_READ | KDB_ENABLE_FLOW_CTRL,
512 			     kdb_cmd_enabled, false))
513 		return KDB_NOPERM;
514 
515 	/*
516 	 * Process arguments which follow the following syntax:
517 	 *
518 	 *  symbol | numeric-address [+/- numeric-offset]
519 	 *  %register
520 	 *  $environment-variable
521 	 */
522 
523 	if (*nextarg > argc)
524 		return KDB_ARGCOUNT;
525 
526 	symname = (char *)argv[*nextarg];
527 
528 	/*
529 	 * If there is no whitespace between the symbol
530 	 * or address and the '+' or '-' symbols, we
531 	 * remember the character and replace it with a
532 	 * null so the symbol/value can be properly parsed
533 	 */
534 	cp = strpbrk(symname, "+-");
535 	if (cp != NULL) {
536 		symbol = *cp;
537 		*cp++ = '\0';
538 	}
539 
540 	if (symname[0] == '$') {
541 		diag = kdbgetulenv(&symname[1], &addr);
542 		if (diag)
543 			return diag;
544 	} else if (symname[0] == '%') {
545 		diag = kdb_check_regs();
546 		if (diag)
547 			return diag;
548 		/* Implement register values with % at a later time as it is
549 		 * arch optional.
550 		 */
551 		return KDB_NOTIMP;
552 	} else {
553 		found = kdbgetsymval(symname, &symtab);
554 		if (found) {
555 			addr = symtab.sym_start;
556 		} else {
557 			diag = kdbgetularg(argv[*nextarg], &addr);
558 			if (diag)
559 				return diag;
560 		}
561 	}
562 
563 	if (!found)
564 		found = kdbnearsym(addr, &symtab);
565 
566 	(*nextarg)++;
567 
568 	if (name)
569 		*name = symname;
570 	if (value)
571 		*value = addr;
572 	if (offset && name && *name)
573 		*offset = addr - symtab.sym_start;
574 
575 	if ((*nextarg > argc)
576 	 && (symbol == '\0'))
577 		return 0;
578 
579 	/*
580 	 * check for +/- and offset
581 	 */
582 
583 	if (symbol == '\0') {
584 		if ((argv[*nextarg][0] != '+')
585 		 && (argv[*nextarg][0] != '-')) {
586 			/*
587 			 * Not our argument.  Return.
588 			 */
589 			return 0;
590 		} else {
591 			positive = (argv[*nextarg][0] == '+');
592 			(*nextarg)++;
593 		}
594 	} else
595 		positive = (symbol == '+');
596 
597 	/*
598 	 * Now there must be an offset!
599 	 */
600 	if ((*nextarg > argc)
601 	 && (symbol == '\0')) {
602 		return KDB_INVADDRFMT;
603 	}
604 
605 	if (!symbol) {
606 		cp = (char *)argv[*nextarg];
607 		(*nextarg)++;
608 	}
609 
610 	diag = kdbgetularg(cp, &off);
611 	if (diag)
612 		return diag;
613 
614 	if (!positive)
615 		off = -off;
616 
617 	if (offset)
618 		*offset += off;
619 
620 	if (value)
621 		*value += off;
622 
623 	return 0;
624 }
625 
626 static void kdb_cmderror(int diag)
627 {
628 	int i;
629 
630 	if (diag >= 0) {
631 		kdb_printf("no error detected (diagnostic is %d)\n", diag);
632 		return;
633 	}
634 
635 	for (i = 0; i < __nkdb_err; i++) {
636 		if (kdbmsgs[i].km_diag == diag) {
637 			kdb_printf("diag: %d: %s\n", diag, kdbmsgs[i].km_msg);
638 			return;
639 		}
640 	}
641 
642 	kdb_printf("Unknown diag %d\n", -diag);
643 }
644 
645 /*
646  * kdb_defcmd, kdb_defcmd2 - This function implements the 'defcmd'
647  *	command which defines one command as a set of other commands,
648  *	terminated by endefcmd.  kdb_defcmd processes the initial
649  *	'defcmd' command, kdb_defcmd2 is invoked from kdb_parse for
650  *	the following commands until 'endefcmd'.
651  * Inputs:
652  *	argc	argument count
653  *	argv	argument vector
654  * Returns:
655  *	zero for success, a kdb diagnostic if error
656  */
657 struct defcmd_set {
658 	int count;
659 	bool usable;
660 	char *name;
661 	char *usage;
662 	char *help;
663 	char **command;
664 };
665 static struct defcmd_set *defcmd_set;
666 static int defcmd_set_count;
667 static bool defcmd_in_progress;
668 
669 /* Forward references */
670 static int kdb_exec_defcmd(int argc, const char **argv);
671 
672 static int kdb_defcmd2(const char *cmdstr, const char *argv0)
673 {
674 	struct defcmd_set *s = defcmd_set + defcmd_set_count - 1;
675 	char **save_command = s->command;
676 	if (strcmp(argv0, "endefcmd") == 0) {
677 		defcmd_in_progress = false;
678 		if (!s->count)
679 			s->usable = false;
680 		if (s->usable)
681 			/* macros are always safe because when executed each
682 			 * internal command re-enters kdb_parse() and is
683 			 * safety checked individually.
684 			 */
685 			kdb_register_flags(s->name, kdb_exec_defcmd, s->usage,
686 					   s->help, 0,
687 					   KDB_ENABLE_ALWAYS_SAFE);
688 		return 0;
689 	}
690 	if (!s->usable)
691 		return KDB_NOTIMP;
692 	s->command = kcalloc(s->count + 1, sizeof(*(s->command)), GFP_KDB);
693 	if (!s->command) {
694 		kdb_printf("Could not allocate new kdb_defcmd table for %s\n",
695 			   cmdstr);
696 		s->usable = false;
697 		return KDB_NOTIMP;
698 	}
699 	memcpy(s->command, save_command, s->count * sizeof(*(s->command)));
700 	s->command[s->count++] = kdb_strdup(cmdstr, GFP_KDB);
701 	kfree(save_command);
702 	return 0;
703 }
704 
705 static int kdb_defcmd(int argc, const char **argv)
706 {
707 	struct defcmd_set *save_defcmd_set = defcmd_set, *s;
708 	if (defcmd_in_progress) {
709 		kdb_printf("kdb: nested defcmd detected, assuming missing "
710 			   "endefcmd\n");
711 		kdb_defcmd2("endefcmd", "endefcmd");
712 	}
713 	if (argc == 0) {
714 		int i;
715 		for (s = defcmd_set; s < defcmd_set + defcmd_set_count; ++s) {
716 			kdb_printf("defcmd %s \"%s\" \"%s\"\n", s->name,
717 				   s->usage, s->help);
718 			for (i = 0; i < s->count; ++i)
719 				kdb_printf("%s", s->command[i]);
720 			kdb_printf("endefcmd\n");
721 		}
722 		return 0;
723 	}
724 	if (argc != 3)
725 		return KDB_ARGCOUNT;
726 	if (in_dbg_master()) {
727 		kdb_printf("Command only available during kdb_init()\n");
728 		return KDB_NOTIMP;
729 	}
730 	defcmd_set = kmalloc_array(defcmd_set_count + 1, sizeof(*defcmd_set),
731 				   GFP_KDB);
732 	if (!defcmd_set)
733 		goto fail_defcmd;
734 	memcpy(defcmd_set, save_defcmd_set,
735 	       defcmd_set_count * sizeof(*defcmd_set));
736 	s = defcmd_set + defcmd_set_count;
737 	memset(s, 0, sizeof(*s));
738 	s->usable = true;
739 	s->name = kdb_strdup(argv[1], GFP_KDB);
740 	if (!s->name)
741 		goto fail_name;
742 	s->usage = kdb_strdup(argv[2], GFP_KDB);
743 	if (!s->usage)
744 		goto fail_usage;
745 	s->help = kdb_strdup(argv[3], GFP_KDB);
746 	if (!s->help)
747 		goto fail_help;
748 	if (s->usage[0] == '"') {
749 		strcpy(s->usage, argv[2]+1);
750 		s->usage[strlen(s->usage)-1] = '\0';
751 	}
752 	if (s->help[0] == '"') {
753 		strcpy(s->help, argv[3]+1);
754 		s->help[strlen(s->help)-1] = '\0';
755 	}
756 	++defcmd_set_count;
757 	defcmd_in_progress = true;
758 	kfree(save_defcmd_set);
759 	return 0;
760 fail_help:
761 	kfree(s->usage);
762 fail_usage:
763 	kfree(s->name);
764 fail_name:
765 	kfree(defcmd_set);
766 fail_defcmd:
767 	kdb_printf("Could not allocate new defcmd_set entry for %s\n", argv[1]);
768 	defcmd_set = save_defcmd_set;
769 	return KDB_NOTIMP;
770 }
771 
772 /*
773  * kdb_exec_defcmd - Execute the set of commands associated with this
774  *	defcmd name.
775  * Inputs:
776  *	argc	argument count
777  *	argv	argument vector
778  * Returns:
779  *	zero for success, a kdb diagnostic if error
780  */
781 static int kdb_exec_defcmd(int argc, const char **argv)
782 {
783 	int i, ret;
784 	struct defcmd_set *s;
785 	if (argc != 0)
786 		return KDB_ARGCOUNT;
787 	for (s = defcmd_set, i = 0; i < defcmd_set_count; ++i, ++s) {
788 		if (strcmp(s->name, argv[0]) == 0)
789 			break;
790 	}
791 	if (i == defcmd_set_count) {
792 		kdb_printf("kdb_exec_defcmd: could not find commands for %s\n",
793 			   argv[0]);
794 		return KDB_NOTIMP;
795 	}
796 	for (i = 0; i < s->count; ++i) {
797 		/* Recursive use of kdb_parse, do not use argv after
798 		 * this point */
799 		argv = NULL;
800 		kdb_printf("[%s]kdb> %s\n", s->name, s->command[i]);
801 		ret = kdb_parse(s->command[i]);
802 		if (ret)
803 			return ret;
804 	}
805 	return 0;
806 }
807 
808 /* Command history */
809 #define KDB_CMD_HISTORY_COUNT	32
810 #define CMD_BUFLEN		200	/* kdb_printf: max printline
811 					 * size == 256 */
812 static unsigned int cmd_head, cmd_tail;
813 static unsigned int cmdptr;
814 static char cmd_hist[KDB_CMD_HISTORY_COUNT][CMD_BUFLEN];
815 static char cmd_cur[CMD_BUFLEN];
816 
817 /*
818  * The "str" argument may point to something like  | grep xyz
819  */
820 static void parse_grep(const char *str)
821 {
822 	int	len;
823 	char	*cp = (char *)str, *cp2;
824 
825 	/* sanity check: we should have been called with the \ first */
826 	if (*cp != '|')
827 		return;
828 	cp++;
829 	while (isspace(*cp))
830 		cp++;
831 	if (!str_has_prefix(cp, "grep ")) {
832 		kdb_printf("invalid 'pipe', see grephelp\n");
833 		return;
834 	}
835 	cp += 5;
836 	while (isspace(*cp))
837 		cp++;
838 	cp2 = strchr(cp, '\n');
839 	if (cp2)
840 		*cp2 = '\0'; /* remove the trailing newline */
841 	len = strlen(cp);
842 	if (len == 0) {
843 		kdb_printf("invalid 'pipe', see grephelp\n");
844 		return;
845 	}
846 	/* now cp points to a nonzero length search string */
847 	if (*cp == '"') {
848 		/* allow it be "x y z" by removing the "'s - there must
849 		   be two of them */
850 		cp++;
851 		cp2 = strchr(cp, '"');
852 		if (!cp2) {
853 			kdb_printf("invalid quoted string, see grephelp\n");
854 			return;
855 		}
856 		*cp2 = '\0'; /* end the string where the 2nd " was */
857 	}
858 	kdb_grep_leading = 0;
859 	if (*cp == '^') {
860 		kdb_grep_leading = 1;
861 		cp++;
862 	}
863 	len = strlen(cp);
864 	kdb_grep_trailing = 0;
865 	if (*(cp+len-1) == '$') {
866 		kdb_grep_trailing = 1;
867 		*(cp+len-1) = '\0';
868 	}
869 	len = strlen(cp);
870 	if (!len)
871 		return;
872 	if (len >= KDB_GREP_STRLEN) {
873 		kdb_printf("search string too long\n");
874 		return;
875 	}
876 	strcpy(kdb_grep_string, cp);
877 	kdb_grepping_flag++;
878 	return;
879 }
880 
881 /*
882  * kdb_parse - Parse the command line, search the command table for a
883  *	matching command and invoke the command function.  This
884  *	function may be called recursively, if it is, the second call
885  *	will overwrite argv and cbuf.  It is the caller's
886  *	responsibility to save their argv if they recursively call
887  *	kdb_parse().
888  * Parameters:
889  *      cmdstr	The input command line to be parsed.
890  *	regs	The registers at the time kdb was entered.
891  * Returns:
892  *	Zero for success, a kdb diagnostic if failure.
893  * Remarks:
894  *	Limited to 20 tokens.
895  *
896  *	Real rudimentary tokenization. Basically only whitespace
897  *	is considered a token delimeter (but special consideration
898  *	is taken of the '=' sign as used by the 'set' command).
899  *
900  *	The algorithm used to tokenize the input string relies on
901  *	there being at least one whitespace (or otherwise useless)
902  *	character between tokens as the character immediately following
903  *	the token is altered in-place to a null-byte to terminate the
904  *	token string.
905  */
906 
907 #define MAXARGC	20
908 
909 int kdb_parse(const char *cmdstr)
910 {
911 	static char *argv[MAXARGC];
912 	static int argc;
913 	static char cbuf[CMD_BUFLEN+2];
914 	char *cp;
915 	char *cpp, quoted;
916 	kdbtab_t *tp;
917 	int escaped, ignore_errors = 0, check_grep = 0;
918 
919 	/*
920 	 * First tokenize the command string.
921 	 */
922 	cp = (char *)cmdstr;
923 
924 	if (KDB_FLAG(CMD_INTERRUPT)) {
925 		/* Previous command was interrupted, newline must not
926 		 * repeat the command */
927 		KDB_FLAG_CLEAR(CMD_INTERRUPT);
928 		KDB_STATE_SET(PAGER);
929 		argc = 0;	/* no repeat */
930 	}
931 
932 	if (*cp != '\n' && *cp != '\0') {
933 		argc = 0;
934 		cpp = cbuf;
935 		while (*cp) {
936 			/* skip whitespace */
937 			while (isspace(*cp))
938 				cp++;
939 			if ((*cp == '\0') || (*cp == '\n') ||
940 			    (*cp == '#' && !defcmd_in_progress))
941 				break;
942 			/* special case: check for | grep pattern */
943 			if (*cp == '|') {
944 				check_grep++;
945 				break;
946 			}
947 			if (cpp >= cbuf + CMD_BUFLEN) {
948 				kdb_printf("kdb_parse: command buffer "
949 					   "overflow, command ignored\n%s\n",
950 					   cmdstr);
951 				return KDB_NOTFOUND;
952 			}
953 			if (argc >= MAXARGC - 1) {
954 				kdb_printf("kdb_parse: too many arguments, "
955 					   "command ignored\n%s\n", cmdstr);
956 				return KDB_NOTFOUND;
957 			}
958 			argv[argc++] = cpp;
959 			escaped = 0;
960 			quoted = '\0';
961 			/* Copy to next unquoted and unescaped
962 			 * whitespace or '=' */
963 			while (*cp && *cp != '\n' &&
964 			       (escaped || quoted || !isspace(*cp))) {
965 				if (cpp >= cbuf + CMD_BUFLEN)
966 					break;
967 				if (escaped) {
968 					escaped = 0;
969 					*cpp++ = *cp++;
970 					continue;
971 				}
972 				if (*cp == '\\') {
973 					escaped = 1;
974 					++cp;
975 					continue;
976 				}
977 				if (*cp == quoted)
978 					quoted = '\0';
979 				else if (*cp == '\'' || *cp == '"')
980 					quoted = *cp;
981 				*cpp = *cp++;
982 				if (*cpp == '=' && !quoted)
983 					break;
984 				++cpp;
985 			}
986 			*cpp++ = '\0';	/* Squash a ws or '=' character */
987 		}
988 	}
989 	if (!argc)
990 		return 0;
991 	if (check_grep)
992 		parse_grep(cp);
993 	if (defcmd_in_progress) {
994 		int result = kdb_defcmd2(cmdstr, argv[0]);
995 		if (!defcmd_in_progress) {
996 			argc = 0;	/* avoid repeat on endefcmd */
997 			*(argv[0]) = '\0';
998 		}
999 		return result;
1000 	}
1001 	if (argv[0][0] == '-' && argv[0][1] &&
1002 	    (argv[0][1] < '0' || argv[0][1] > '9')) {
1003 		ignore_errors = 1;
1004 		++argv[0];
1005 	}
1006 
1007 	list_for_each_entry(tp, &kdb_cmds_head, list_node) {
1008 		/*
1009 		 * If this command is allowed to be abbreviated,
1010 		 * check to see if this is it.
1011 		 */
1012 		if (tp->cmd_minlen && (strlen(argv[0]) <= tp->cmd_minlen) &&
1013 		    (strncmp(argv[0], tp->cmd_name, tp->cmd_minlen) == 0))
1014 			break;
1015 
1016 		if (strcmp(argv[0], tp->cmd_name) == 0)
1017 			break;
1018 	}
1019 
1020 	/*
1021 	 * If we don't find a command by this name, see if the first
1022 	 * few characters of this match any of the known commands.
1023 	 * e.g., md1c20 should match md.
1024 	 */
1025 	if (list_entry_is_head(tp, &kdb_cmds_head, list_node)) {
1026 		list_for_each_entry(tp, &kdb_cmds_head, list_node) {
1027 			if (strncmp(argv[0], tp->cmd_name,
1028 				    strlen(tp->cmd_name)) == 0)
1029 				break;
1030 		}
1031 	}
1032 
1033 	if (!list_entry_is_head(tp, &kdb_cmds_head, list_node)) {
1034 		int result;
1035 
1036 		if (!kdb_check_flags(tp->cmd_flags, kdb_cmd_enabled, argc <= 1))
1037 			return KDB_NOPERM;
1038 
1039 		KDB_STATE_SET(CMD);
1040 		result = (*tp->cmd_func)(argc-1, (const char **)argv);
1041 		if (result && ignore_errors && result > KDB_CMD_GO)
1042 			result = 0;
1043 		KDB_STATE_CLEAR(CMD);
1044 
1045 		if (tp->cmd_flags & KDB_REPEAT_WITH_ARGS)
1046 			return result;
1047 
1048 		argc = tp->cmd_flags & KDB_REPEAT_NO_ARGS ? 1 : 0;
1049 		if (argv[argc])
1050 			*(argv[argc]) = '\0';
1051 		return result;
1052 	}
1053 
1054 	/*
1055 	 * If the input with which we were presented does not
1056 	 * map to an existing command, attempt to parse it as an
1057 	 * address argument and display the result.   Useful for
1058 	 * obtaining the address of a variable, or the nearest symbol
1059 	 * to an address contained in a register.
1060 	 */
1061 	{
1062 		unsigned long value;
1063 		char *name = NULL;
1064 		long offset;
1065 		int nextarg = 0;
1066 
1067 		if (kdbgetaddrarg(0, (const char **)argv, &nextarg,
1068 				  &value, &offset, &name)) {
1069 			return KDB_NOTFOUND;
1070 		}
1071 
1072 		kdb_printf("%s = ", argv[0]);
1073 		kdb_symbol_print(value, NULL, KDB_SP_DEFAULT);
1074 		kdb_printf("\n");
1075 		return 0;
1076 	}
1077 }
1078 
1079 
1080 static int handle_ctrl_cmd(char *cmd)
1081 {
1082 #define CTRL_P	16
1083 #define CTRL_N	14
1084 
1085 	/* initial situation */
1086 	if (cmd_head == cmd_tail)
1087 		return 0;
1088 	switch (*cmd) {
1089 	case CTRL_P:
1090 		if (cmdptr != cmd_tail)
1091 			cmdptr = (cmdptr + KDB_CMD_HISTORY_COUNT - 1) %
1092 				 KDB_CMD_HISTORY_COUNT;
1093 		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
1094 		return 1;
1095 	case CTRL_N:
1096 		if (cmdptr != cmd_head)
1097 			cmdptr = (cmdptr+1) % KDB_CMD_HISTORY_COUNT;
1098 		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
1099 		return 1;
1100 	}
1101 	return 0;
1102 }
1103 
1104 /*
1105  * kdb_reboot - This function implements the 'reboot' command.  Reboot
1106  *	the system immediately, or loop for ever on failure.
1107  */
1108 static int kdb_reboot(int argc, const char **argv)
1109 {
1110 	emergency_restart();
1111 	kdb_printf("Hmm, kdb_reboot did not reboot, spinning here\n");
1112 	while (1)
1113 		cpu_relax();
1114 	/* NOTREACHED */
1115 	return 0;
1116 }
1117 
1118 static void kdb_dumpregs(struct pt_regs *regs)
1119 {
1120 	int old_lvl = console_loglevel;
1121 	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
1122 	kdb_trap_printk++;
1123 	show_regs(regs);
1124 	kdb_trap_printk--;
1125 	kdb_printf("\n");
1126 	console_loglevel = old_lvl;
1127 }
1128 
1129 static void kdb_set_current_task(struct task_struct *p)
1130 {
1131 	kdb_current_task = p;
1132 
1133 	if (kdb_task_has_cpu(p)) {
1134 		kdb_current_regs = KDB_TSKREGS(kdb_process_cpu(p));
1135 		return;
1136 	}
1137 	kdb_current_regs = NULL;
1138 }
1139 
1140 static void drop_newline(char *buf)
1141 {
1142 	size_t len = strlen(buf);
1143 
1144 	if (len == 0)
1145 		return;
1146 	if (*(buf + len - 1) == '\n')
1147 		*(buf + len - 1) = '\0';
1148 }
1149 
1150 /*
1151  * kdb_local - The main code for kdb.  This routine is invoked on a
1152  *	specific processor, it is not global.  The main kdb() routine
1153  *	ensures that only one processor at a time is in this routine.
1154  *	This code is called with the real reason code on the first
1155  *	entry to a kdb session, thereafter it is called with reason
1156  *	SWITCH, even if the user goes back to the original cpu.
1157  * Inputs:
1158  *	reason		The reason KDB was invoked
1159  *	error		The hardware-defined error code
1160  *	regs		The exception frame at time of fault/breakpoint.
1161  *	db_result	Result code from the break or debug point.
1162  * Returns:
1163  *	0	KDB was invoked for an event which it wasn't responsible
1164  *	1	KDB handled the event for which it was invoked.
1165  *	KDB_CMD_GO	User typed 'go'.
1166  *	KDB_CMD_CPU	User switched to another cpu.
1167  *	KDB_CMD_SS	Single step.
1168  */
1169 static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
1170 		     kdb_dbtrap_t db_result)
1171 {
1172 	char *cmdbuf;
1173 	int diag;
1174 	struct task_struct *kdb_current =
1175 		kdb_curr_task(raw_smp_processor_id());
1176 
1177 	KDB_DEBUG_STATE("kdb_local 1", reason);
1178 	kdb_go_count = 0;
1179 	if (reason == KDB_REASON_DEBUG) {
1180 		/* special case below */
1181 	} else {
1182 		kdb_printf("\nEntering kdb (current=0x%px, pid %d) ",
1183 			   kdb_current, kdb_current ? kdb_current->pid : 0);
1184 #if defined(CONFIG_SMP)
1185 		kdb_printf("on processor %d ", raw_smp_processor_id());
1186 #endif
1187 	}
1188 
1189 	switch (reason) {
1190 	case KDB_REASON_DEBUG:
1191 	{
1192 		/*
1193 		 * If re-entering kdb after a single step
1194 		 * command, don't print the message.
1195 		 */
1196 		switch (db_result) {
1197 		case KDB_DB_BPT:
1198 			kdb_printf("\nEntering kdb (0x%px, pid %d) ",
1199 				   kdb_current, kdb_current->pid);
1200 #if defined(CONFIG_SMP)
1201 			kdb_printf("on processor %d ", raw_smp_processor_id());
1202 #endif
1203 			kdb_printf("due to Debug @ " kdb_machreg_fmt "\n",
1204 				   instruction_pointer(regs));
1205 			break;
1206 		case KDB_DB_SS:
1207 			break;
1208 		case KDB_DB_SSBPT:
1209 			KDB_DEBUG_STATE("kdb_local 4", reason);
1210 			return 1;	/* kdba_db_trap did the work */
1211 		default:
1212 			kdb_printf("kdb: Bad result from kdba_db_trap: %d\n",
1213 				   db_result);
1214 			break;
1215 		}
1216 
1217 	}
1218 		break;
1219 	case KDB_REASON_ENTER:
1220 		if (KDB_STATE(KEYBOARD))
1221 			kdb_printf("due to Keyboard Entry\n");
1222 		else
1223 			kdb_printf("due to KDB_ENTER()\n");
1224 		break;
1225 	case KDB_REASON_KEYBOARD:
1226 		KDB_STATE_SET(KEYBOARD);
1227 		kdb_printf("due to Keyboard Entry\n");
1228 		break;
1229 	case KDB_REASON_ENTER_SLAVE:
1230 		/* drop through, slaves only get released via cpu switch */
1231 	case KDB_REASON_SWITCH:
1232 		kdb_printf("due to cpu switch\n");
1233 		break;
1234 	case KDB_REASON_OOPS:
1235 		kdb_printf("Oops: %s\n", kdb_diemsg);
1236 		kdb_printf("due to oops @ " kdb_machreg_fmt "\n",
1237 			   instruction_pointer(regs));
1238 		kdb_dumpregs(regs);
1239 		break;
1240 	case KDB_REASON_SYSTEM_NMI:
1241 		kdb_printf("due to System NonMaskable Interrupt\n");
1242 		break;
1243 	case KDB_REASON_NMI:
1244 		kdb_printf("due to NonMaskable Interrupt @ "
1245 			   kdb_machreg_fmt "\n",
1246 			   instruction_pointer(regs));
1247 		break;
1248 	case KDB_REASON_SSTEP:
1249 	case KDB_REASON_BREAK:
1250 		kdb_printf("due to %s @ " kdb_machreg_fmt "\n",
1251 			   reason == KDB_REASON_BREAK ?
1252 			   "Breakpoint" : "SS trap", instruction_pointer(regs));
1253 		/*
1254 		 * Determine if this breakpoint is one that we
1255 		 * are interested in.
1256 		 */
1257 		if (db_result != KDB_DB_BPT) {
1258 			kdb_printf("kdb: error return from kdba_bp_trap: %d\n",
1259 				   db_result);
1260 			KDB_DEBUG_STATE("kdb_local 6", reason);
1261 			return 0;	/* Not for us, dismiss it */
1262 		}
1263 		break;
1264 	case KDB_REASON_RECURSE:
1265 		kdb_printf("due to Recursion @ " kdb_machreg_fmt "\n",
1266 			   instruction_pointer(regs));
1267 		break;
1268 	default:
1269 		kdb_printf("kdb: unexpected reason code: %d\n", reason);
1270 		KDB_DEBUG_STATE("kdb_local 8", reason);
1271 		return 0;	/* Not for us, dismiss it */
1272 	}
1273 
1274 	while (1) {
1275 		/*
1276 		 * Initialize pager context.
1277 		 */
1278 		kdb_nextline = 1;
1279 		KDB_STATE_CLEAR(SUPPRESS);
1280 		kdb_grepping_flag = 0;
1281 		/* ensure the old search does not leak into '/' commands */
1282 		kdb_grep_string[0] = '\0';
1283 
1284 		cmdbuf = cmd_cur;
1285 		*cmdbuf = '\0';
1286 		*(cmd_hist[cmd_head]) = '\0';
1287 
1288 do_full_getstr:
1289 		/* PROMPT can only be set if we have MEM_READ permission. */
1290 		snprintf(kdb_prompt_str, CMD_BUFLEN, kdbgetenv("PROMPT"),
1291 			 raw_smp_processor_id());
1292 		if (defcmd_in_progress)
1293 			strncat(kdb_prompt_str, "[defcmd]", CMD_BUFLEN);
1294 
1295 		/*
1296 		 * Fetch command from keyboard
1297 		 */
1298 		cmdbuf = kdb_getstr(cmdbuf, CMD_BUFLEN, kdb_prompt_str);
1299 		if (*cmdbuf != '\n') {
1300 			if (*cmdbuf < 32) {
1301 				if (cmdptr == cmd_head) {
1302 					strscpy(cmd_hist[cmd_head], cmd_cur,
1303 						CMD_BUFLEN);
1304 					*(cmd_hist[cmd_head] +
1305 					  strlen(cmd_hist[cmd_head])-1) = '\0';
1306 				}
1307 				if (!handle_ctrl_cmd(cmdbuf))
1308 					*(cmd_cur+strlen(cmd_cur)-1) = '\0';
1309 				cmdbuf = cmd_cur;
1310 				goto do_full_getstr;
1311 			} else {
1312 				strscpy(cmd_hist[cmd_head], cmd_cur,
1313 					CMD_BUFLEN);
1314 			}
1315 
1316 			cmd_head = (cmd_head+1) % KDB_CMD_HISTORY_COUNT;
1317 			if (cmd_head == cmd_tail)
1318 				cmd_tail = (cmd_tail+1) % KDB_CMD_HISTORY_COUNT;
1319 		}
1320 
1321 		cmdptr = cmd_head;
1322 		diag = kdb_parse(cmdbuf);
1323 		if (diag == KDB_NOTFOUND) {
1324 			drop_newline(cmdbuf);
1325 			kdb_printf("Unknown kdb command: '%s'\n", cmdbuf);
1326 			diag = 0;
1327 		}
1328 		if (diag == KDB_CMD_GO
1329 		 || diag == KDB_CMD_CPU
1330 		 || diag == KDB_CMD_SS
1331 		 || diag == KDB_CMD_KGDB)
1332 			break;
1333 
1334 		if (diag)
1335 			kdb_cmderror(diag);
1336 	}
1337 	KDB_DEBUG_STATE("kdb_local 9", diag);
1338 	return diag;
1339 }
1340 
1341 
1342 /*
1343  * kdb_print_state - Print the state data for the current processor
1344  *	for debugging.
1345  * Inputs:
1346  *	text		Identifies the debug point
1347  *	value		Any integer value to be printed, e.g. reason code.
1348  */
1349 void kdb_print_state(const char *text, int value)
1350 {
1351 	kdb_printf("state: %s cpu %d value %d initial %d state %x\n",
1352 		   text, raw_smp_processor_id(), value, kdb_initial_cpu,
1353 		   kdb_state);
1354 }
1355 
1356 /*
1357  * kdb_main_loop - After initial setup and assignment of the
1358  *	controlling cpu, all cpus are in this loop.  One cpu is in
1359  *	control and will issue the kdb prompt, the others will spin
1360  *	until 'go' or cpu switch.
1361  *
1362  *	To get a consistent view of the kernel stacks for all
1363  *	processes, this routine is invoked from the main kdb code via
1364  *	an architecture specific routine.  kdba_main_loop is
1365  *	responsible for making the kernel stacks consistent for all
1366  *	processes, there should be no difference between a blocked
1367  *	process and a running process as far as kdb is concerned.
1368  * Inputs:
1369  *	reason		The reason KDB was invoked
1370  *	error		The hardware-defined error code
1371  *	reason2		kdb's current reason code.
1372  *			Initially error but can change
1373  *			according to kdb state.
1374  *	db_result	Result code from break or debug point.
1375  *	regs		The exception frame at time of fault/breakpoint.
1376  *			should always be valid.
1377  * Returns:
1378  *	0	KDB was invoked for an event which it wasn't responsible
1379  *	1	KDB handled the event for which it was invoked.
1380  */
1381 int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error,
1382 	      kdb_dbtrap_t db_result, struct pt_regs *regs)
1383 {
1384 	int result = 1;
1385 	/* Stay in kdb() until 'go', 'ss[b]' or an error */
1386 	while (1) {
1387 		/*
1388 		 * All processors except the one that is in control
1389 		 * will spin here.
1390 		 */
1391 		KDB_DEBUG_STATE("kdb_main_loop 1", reason);
1392 		while (KDB_STATE(HOLD_CPU)) {
1393 			/* state KDB is turned off by kdb_cpu to see if the
1394 			 * other cpus are still live, each cpu in this loop
1395 			 * turns it back on.
1396 			 */
1397 			if (!KDB_STATE(KDB))
1398 				KDB_STATE_SET(KDB);
1399 		}
1400 
1401 		KDB_STATE_CLEAR(SUPPRESS);
1402 		KDB_DEBUG_STATE("kdb_main_loop 2", reason);
1403 		if (KDB_STATE(LEAVING))
1404 			break;	/* Another cpu said 'go' */
1405 		/* Still using kdb, this processor is in control */
1406 		result = kdb_local(reason2, error, regs, db_result);
1407 		KDB_DEBUG_STATE("kdb_main_loop 3", result);
1408 
1409 		if (result == KDB_CMD_CPU)
1410 			break;
1411 
1412 		if (result == KDB_CMD_SS) {
1413 			KDB_STATE_SET(DOING_SS);
1414 			break;
1415 		}
1416 
1417 		if (result == KDB_CMD_KGDB) {
1418 			if (!KDB_STATE(DOING_KGDB))
1419 				kdb_printf("Entering please attach debugger "
1420 					   "or use $D#44+ or $3#33\n");
1421 			break;
1422 		}
1423 		if (result && result != 1 && result != KDB_CMD_GO)
1424 			kdb_printf("\nUnexpected kdb_local return code %d\n",
1425 				   result);
1426 		KDB_DEBUG_STATE("kdb_main_loop 4", reason);
1427 		break;
1428 	}
1429 	if (KDB_STATE(DOING_SS))
1430 		KDB_STATE_CLEAR(SSBPT);
1431 
1432 	/* Clean up any keyboard devices before leaving */
1433 	kdb_kbd_cleanup_state();
1434 
1435 	return result;
1436 }
1437 
1438 /*
1439  * kdb_mdr - This function implements the guts of the 'mdr', memory
1440  * read command.
1441  *	mdr  <addr arg>,<byte count>
1442  * Inputs:
1443  *	addr	Start address
1444  *	count	Number of bytes
1445  * Returns:
1446  *	Always 0.  Any errors are detected and printed by kdb_getarea.
1447  */
1448 static int kdb_mdr(unsigned long addr, unsigned int count)
1449 {
1450 	unsigned char c;
1451 	while (count--) {
1452 		if (kdb_getarea(c, addr))
1453 			return 0;
1454 		kdb_printf("%02x", c);
1455 		addr++;
1456 	}
1457 	kdb_printf("\n");
1458 	return 0;
1459 }
1460 
1461 /*
1462  * kdb_md - This function implements the 'md', 'md1', 'md2', 'md4',
1463  *	'md8' 'mdr' and 'mds' commands.
1464  *
1465  *	md|mds  [<addr arg> [<line count> [<radix>]]]
1466  *	mdWcN	[<addr arg> [<line count> [<radix>]]]
1467  *		where W = is the width (1, 2, 4 or 8) and N is the count.
1468  *		for eg., md1c20 reads 20 bytes, 1 at a time.
1469  *	mdr  <addr arg>,<byte count>
1470  */
1471 static void kdb_md_line(const char *fmtstr, unsigned long addr,
1472 			int symbolic, int nosect, int bytesperword,
1473 			int num, int repeat, int phys)
1474 {
1475 	/* print just one line of data */
1476 	kdb_symtab_t symtab;
1477 	char cbuf[32];
1478 	char *c = cbuf;
1479 	int i;
1480 	int j;
1481 	unsigned long word;
1482 
1483 	memset(cbuf, '\0', sizeof(cbuf));
1484 	if (phys)
1485 		kdb_printf("phys " kdb_machreg_fmt0 " ", addr);
1486 	else
1487 		kdb_printf(kdb_machreg_fmt0 " ", addr);
1488 
1489 	for (i = 0; i < num && repeat--; i++) {
1490 		if (phys) {
1491 			if (kdb_getphysword(&word, addr, bytesperword))
1492 				break;
1493 		} else if (kdb_getword(&word, addr, bytesperword))
1494 			break;
1495 		kdb_printf(fmtstr, word);
1496 		if (symbolic)
1497 			kdbnearsym(word, &symtab);
1498 		else
1499 			memset(&symtab, 0, sizeof(symtab));
1500 		if (symtab.sym_name) {
1501 			kdb_symbol_print(word, &symtab, 0);
1502 			if (!nosect) {
1503 				kdb_printf("\n");
1504 				kdb_printf("                       %s %s "
1505 					   kdb_machreg_fmt " "
1506 					   kdb_machreg_fmt " "
1507 					   kdb_machreg_fmt, symtab.mod_name,
1508 					   symtab.sec_name, symtab.sec_start,
1509 					   symtab.sym_start, symtab.sym_end);
1510 			}
1511 			addr += bytesperword;
1512 		} else {
1513 			union {
1514 				u64 word;
1515 				unsigned char c[8];
1516 			} wc;
1517 			unsigned char *cp;
1518 #ifdef	__BIG_ENDIAN
1519 			cp = wc.c + 8 - bytesperword;
1520 #else
1521 			cp = wc.c;
1522 #endif
1523 			wc.word = word;
1524 #define printable_char(c) \
1525 	({unsigned char __c = c; isascii(__c) && isprint(__c) ? __c : '.'; })
1526 			for (j = 0; j < bytesperword; j++)
1527 				*c++ = printable_char(*cp++);
1528 			addr += bytesperword;
1529 #undef printable_char
1530 		}
1531 	}
1532 	kdb_printf("%*s %s\n", (int)((num-i)*(2*bytesperword + 1)+1),
1533 		   " ", cbuf);
1534 }
1535 
1536 static int kdb_md(int argc, const char **argv)
1537 {
1538 	static unsigned long last_addr;
1539 	static int last_radix, last_bytesperword, last_repeat;
1540 	int radix = 16, mdcount = 8, bytesperword = KDB_WORD_SIZE, repeat;
1541 	int nosect = 0;
1542 	char fmtchar, fmtstr[64];
1543 	unsigned long addr;
1544 	unsigned long word;
1545 	long offset = 0;
1546 	int symbolic = 0;
1547 	int valid = 0;
1548 	int phys = 0;
1549 	int raw = 0;
1550 
1551 	kdbgetintenv("MDCOUNT", &mdcount);
1552 	kdbgetintenv("RADIX", &radix);
1553 	kdbgetintenv("BYTESPERWORD", &bytesperword);
1554 
1555 	/* Assume 'md <addr>' and start with environment values */
1556 	repeat = mdcount * 16 / bytesperword;
1557 
1558 	if (strcmp(argv[0], "mdr") == 0) {
1559 		if (argc == 2 || (argc == 0 && last_addr != 0))
1560 			valid = raw = 1;
1561 		else
1562 			return KDB_ARGCOUNT;
1563 	} else if (isdigit(argv[0][2])) {
1564 		bytesperword = (int)(argv[0][2] - '0');
1565 		if (bytesperword == 0) {
1566 			bytesperword = last_bytesperword;
1567 			if (bytesperword == 0)
1568 				bytesperword = 4;
1569 		}
1570 		last_bytesperword = bytesperword;
1571 		repeat = mdcount * 16 / bytesperword;
1572 		if (!argv[0][3])
1573 			valid = 1;
1574 		else if (argv[0][3] == 'c' && argv[0][4]) {
1575 			char *p;
1576 			repeat = simple_strtoul(argv[0] + 4, &p, 10);
1577 			mdcount = ((repeat * bytesperword) + 15) / 16;
1578 			valid = !*p;
1579 		}
1580 		last_repeat = repeat;
1581 	} else if (strcmp(argv[0], "md") == 0)
1582 		valid = 1;
1583 	else if (strcmp(argv[0], "mds") == 0)
1584 		valid = 1;
1585 	else if (strcmp(argv[0], "mdp") == 0) {
1586 		phys = valid = 1;
1587 	}
1588 	if (!valid)
1589 		return KDB_NOTFOUND;
1590 
1591 	if (argc == 0) {
1592 		if (last_addr == 0)
1593 			return KDB_ARGCOUNT;
1594 		addr = last_addr;
1595 		radix = last_radix;
1596 		bytesperword = last_bytesperword;
1597 		repeat = last_repeat;
1598 		if (raw)
1599 			mdcount = repeat;
1600 		else
1601 			mdcount = ((repeat * bytesperword) + 15) / 16;
1602 	}
1603 
1604 	if (argc) {
1605 		unsigned long val;
1606 		int diag, nextarg = 1;
1607 		diag = kdbgetaddrarg(argc, argv, &nextarg, &addr,
1608 				     &offset, NULL);
1609 		if (diag)
1610 			return diag;
1611 		if (argc > nextarg+2)
1612 			return KDB_ARGCOUNT;
1613 
1614 		if (argc >= nextarg) {
1615 			diag = kdbgetularg(argv[nextarg], &val);
1616 			if (!diag) {
1617 				mdcount = (int) val;
1618 				if (raw)
1619 					repeat = mdcount;
1620 				else
1621 					repeat = mdcount * 16 / bytesperword;
1622 			}
1623 		}
1624 		if (argc >= nextarg+1) {
1625 			diag = kdbgetularg(argv[nextarg+1], &val);
1626 			if (!diag)
1627 				radix = (int) val;
1628 		}
1629 	}
1630 
1631 	if (strcmp(argv[0], "mdr") == 0) {
1632 		int ret;
1633 		last_addr = addr;
1634 		ret = kdb_mdr(addr, mdcount);
1635 		last_addr += mdcount;
1636 		last_repeat = mdcount;
1637 		last_bytesperword = bytesperword; // to make REPEAT happy
1638 		return ret;
1639 	}
1640 
1641 	switch (radix) {
1642 	case 10:
1643 		fmtchar = 'd';
1644 		break;
1645 	case 16:
1646 		fmtchar = 'x';
1647 		break;
1648 	case 8:
1649 		fmtchar = 'o';
1650 		break;
1651 	default:
1652 		return KDB_BADRADIX;
1653 	}
1654 
1655 	last_radix = radix;
1656 
1657 	if (bytesperword > KDB_WORD_SIZE)
1658 		return KDB_BADWIDTH;
1659 
1660 	switch (bytesperword) {
1661 	case 8:
1662 		sprintf(fmtstr, "%%16.16l%c ", fmtchar);
1663 		break;
1664 	case 4:
1665 		sprintf(fmtstr, "%%8.8l%c ", fmtchar);
1666 		break;
1667 	case 2:
1668 		sprintf(fmtstr, "%%4.4l%c ", fmtchar);
1669 		break;
1670 	case 1:
1671 		sprintf(fmtstr, "%%2.2l%c ", fmtchar);
1672 		break;
1673 	default:
1674 		return KDB_BADWIDTH;
1675 	}
1676 
1677 	last_repeat = repeat;
1678 	last_bytesperword = bytesperword;
1679 
1680 	if (strcmp(argv[0], "mds") == 0) {
1681 		symbolic = 1;
1682 		/* Do not save these changes as last_*, they are temporary mds
1683 		 * overrides.
1684 		 */
1685 		bytesperword = KDB_WORD_SIZE;
1686 		repeat = mdcount;
1687 		kdbgetintenv("NOSECT", &nosect);
1688 	}
1689 
1690 	/* Round address down modulo BYTESPERWORD */
1691 
1692 	addr &= ~(bytesperword-1);
1693 
1694 	while (repeat > 0) {
1695 		unsigned long a;
1696 		int n, z, num = (symbolic ? 1 : (16 / bytesperword));
1697 
1698 		if (KDB_FLAG(CMD_INTERRUPT))
1699 			return 0;
1700 		for (a = addr, z = 0; z < repeat; a += bytesperword, ++z) {
1701 			if (phys) {
1702 				if (kdb_getphysword(&word, a, bytesperword)
1703 						|| word)
1704 					break;
1705 			} else if (kdb_getword(&word, a, bytesperword) || word)
1706 				break;
1707 		}
1708 		n = min(num, repeat);
1709 		kdb_md_line(fmtstr, addr, symbolic, nosect, bytesperword,
1710 			    num, repeat, phys);
1711 		addr += bytesperword * n;
1712 		repeat -= n;
1713 		z = (z + num - 1) / num;
1714 		if (z > 2) {
1715 			int s = num * (z-2);
1716 			kdb_printf(kdb_machreg_fmt0 "-" kdb_machreg_fmt0
1717 				   " zero suppressed\n",
1718 				addr, addr + bytesperword * s - 1);
1719 			addr += bytesperword * s;
1720 			repeat -= s;
1721 		}
1722 	}
1723 	last_addr = addr;
1724 
1725 	return 0;
1726 }
1727 
1728 /*
1729  * kdb_mm - This function implements the 'mm' command.
1730  *	mm address-expression new-value
1731  * Remarks:
1732  *	mm works on machine words, mmW works on bytes.
1733  */
1734 static int kdb_mm(int argc, const char **argv)
1735 {
1736 	int diag;
1737 	unsigned long addr;
1738 	long offset = 0;
1739 	unsigned long contents;
1740 	int nextarg;
1741 	int width;
1742 
1743 	if (argv[0][2] && !isdigit(argv[0][2]))
1744 		return KDB_NOTFOUND;
1745 
1746 	if (argc < 2)
1747 		return KDB_ARGCOUNT;
1748 
1749 	nextarg = 1;
1750 	diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL);
1751 	if (diag)
1752 		return diag;
1753 
1754 	if (nextarg > argc)
1755 		return KDB_ARGCOUNT;
1756 	diag = kdbgetaddrarg(argc, argv, &nextarg, &contents, NULL, NULL);
1757 	if (diag)
1758 		return diag;
1759 
1760 	if (nextarg != argc + 1)
1761 		return KDB_ARGCOUNT;
1762 
1763 	width = argv[0][2] ? (argv[0][2] - '0') : (KDB_WORD_SIZE);
1764 	diag = kdb_putword(addr, contents, width);
1765 	if (diag)
1766 		return diag;
1767 
1768 	kdb_printf(kdb_machreg_fmt " = " kdb_machreg_fmt "\n", addr, contents);
1769 
1770 	return 0;
1771 }
1772 
1773 /*
1774  * kdb_go - This function implements the 'go' command.
1775  *	go [address-expression]
1776  */
1777 static int kdb_go(int argc, const char **argv)
1778 {
1779 	unsigned long addr;
1780 	int diag;
1781 	int nextarg;
1782 	long offset;
1783 
1784 	if (raw_smp_processor_id() != kdb_initial_cpu) {
1785 		kdb_printf("go must execute on the entry cpu, "
1786 			   "please use \"cpu %d\" and then execute go\n",
1787 			   kdb_initial_cpu);
1788 		return KDB_BADCPUNUM;
1789 	}
1790 	if (argc == 1) {
1791 		nextarg = 1;
1792 		diag = kdbgetaddrarg(argc, argv, &nextarg,
1793 				     &addr, &offset, NULL);
1794 		if (diag)
1795 			return diag;
1796 	} else if (argc) {
1797 		return KDB_ARGCOUNT;
1798 	}
1799 
1800 	diag = KDB_CMD_GO;
1801 	if (KDB_FLAG(CATASTROPHIC)) {
1802 		kdb_printf("Catastrophic error detected\n");
1803 		kdb_printf("kdb_continue_catastrophic=%d, ",
1804 			kdb_continue_catastrophic);
1805 		if (kdb_continue_catastrophic == 0 && kdb_go_count++ == 0) {
1806 			kdb_printf("type go a second time if you really want "
1807 				   "to continue\n");
1808 			return 0;
1809 		}
1810 		if (kdb_continue_catastrophic == 2) {
1811 			kdb_printf("forcing reboot\n");
1812 			kdb_reboot(0, NULL);
1813 		}
1814 		kdb_printf("attempting to continue\n");
1815 	}
1816 	return diag;
1817 }
1818 
1819 /*
1820  * kdb_rd - This function implements the 'rd' command.
1821  */
1822 static int kdb_rd(int argc, const char **argv)
1823 {
1824 	int len = kdb_check_regs();
1825 #if DBG_MAX_REG_NUM > 0
1826 	int i;
1827 	char *rname;
1828 	int rsize;
1829 	u64 reg64;
1830 	u32 reg32;
1831 	u16 reg16;
1832 	u8 reg8;
1833 
1834 	if (len)
1835 		return len;
1836 
1837 	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
1838 		rsize = dbg_reg_def[i].size * 2;
1839 		if (rsize > 16)
1840 			rsize = 2;
1841 		if (len + strlen(dbg_reg_def[i].name) + 4 + rsize > 80) {
1842 			len = 0;
1843 			kdb_printf("\n");
1844 		}
1845 		if (len)
1846 			len += kdb_printf("  ");
1847 		switch(dbg_reg_def[i].size * 8) {
1848 		case 8:
1849 			rname = dbg_get_reg(i, &reg8, kdb_current_regs);
1850 			if (!rname)
1851 				break;
1852 			len += kdb_printf("%s: %02x", rname, reg8);
1853 			break;
1854 		case 16:
1855 			rname = dbg_get_reg(i, &reg16, kdb_current_regs);
1856 			if (!rname)
1857 				break;
1858 			len += kdb_printf("%s: %04x", rname, reg16);
1859 			break;
1860 		case 32:
1861 			rname = dbg_get_reg(i, &reg32, kdb_current_regs);
1862 			if (!rname)
1863 				break;
1864 			len += kdb_printf("%s: %08x", rname, reg32);
1865 			break;
1866 		case 64:
1867 			rname = dbg_get_reg(i, &reg64, kdb_current_regs);
1868 			if (!rname)
1869 				break;
1870 			len += kdb_printf("%s: %016llx", rname, reg64);
1871 			break;
1872 		default:
1873 			len += kdb_printf("%s: ??", dbg_reg_def[i].name);
1874 		}
1875 	}
1876 	kdb_printf("\n");
1877 #else
1878 	if (len)
1879 		return len;
1880 
1881 	kdb_dumpregs(kdb_current_regs);
1882 #endif
1883 	return 0;
1884 }
1885 
1886 /*
1887  * kdb_rm - This function implements the 'rm' (register modify)  command.
1888  *	rm register-name new-contents
1889  * Remarks:
1890  *	Allows register modification with the same restrictions as gdb
1891  */
1892 static int kdb_rm(int argc, const char **argv)
1893 {
1894 #if DBG_MAX_REG_NUM > 0
1895 	int diag;
1896 	const char *rname;
1897 	int i;
1898 	u64 reg64;
1899 	u32 reg32;
1900 	u16 reg16;
1901 	u8 reg8;
1902 
1903 	if (argc != 2)
1904 		return KDB_ARGCOUNT;
1905 	/*
1906 	 * Allow presence or absence of leading '%' symbol.
1907 	 */
1908 	rname = argv[1];
1909 	if (*rname == '%')
1910 		rname++;
1911 
1912 	diag = kdbgetu64arg(argv[2], &reg64);
1913 	if (diag)
1914 		return diag;
1915 
1916 	diag = kdb_check_regs();
1917 	if (diag)
1918 		return diag;
1919 
1920 	diag = KDB_BADREG;
1921 	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
1922 		if (strcmp(rname, dbg_reg_def[i].name) == 0) {
1923 			diag = 0;
1924 			break;
1925 		}
1926 	}
1927 	if (!diag) {
1928 		switch(dbg_reg_def[i].size * 8) {
1929 		case 8:
1930 			reg8 = reg64;
1931 			dbg_set_reg(i, &reg8, kdb_current_regs);
1932 			break;
1933 		case 16:
1934 			reg16 = reg64;
1935 			dbg_set_reg(i, &reg16, kdb_current_regs);
1936 			break;
1937 		case 32:
1938 			reg32 = reg64;
1939 			dbg_set_reg(i, &reg32, kdb_current_regs);
1940 			break;
1941 		case 64:
1942 			dbg_set_reg(i, &reg64, kdb_current_regs);
1943 			break;
1944 		}
1945 	}
1946 	return diag;
1947 #else
1948 	kdb_printf("ERROR: Register set currently not implemented\n");
1949     return 0;
1950 #endif
1951 }
1952 
1953 #if defined(CONFIG_MAGIC_SYSRQ)
1954 /*
1955  * kdb_sr - This function implements the 'sr' (SYSRQ key) command
1956  *	which interfaces to the soi-disant MAGIC SYSRQ functionality.
1957  *		sr <magic-sysrq-code>
1958  */
1959 static int kdb_sr(int argc, const char **argv)
1960 {
1961 	bool check_mask =
1962 	    !kdb_check_flags(KDB_ENABLE_ALL, kdb_cmd_enabled, false);
1963 
1964 	if (argc != 1)
1965 		return KDB_ARGCOUNT;
1966 
1967 	kdb_trap_printk++;
1968 	__handle_sysrq(*argv[1], check_mask);
1969 	kdb_trap_printk--;
1970 
1971 	return 0;
1972 }
1973 #endif	/* CONFIG_MAGIC_SYSRQ */
1974 
1975 /*
1976  * kdb_ef - This function implements the 'regs' (display exception
1977  *	frame) command.  This command takes an address and expects to
1978  *	find an exception frame at that address, formats and prints
1979  *	it.
1980  *		regs address-expression
1981  * Remarks:
1982  *	Not done yet.
1983  */
1984 static int kdb_ef(int argc, const char **argv)
1985 {
1986 	int diag;
1987 	unsigned long addr;
1988 	long offset;
1989 	int nextarg;
1990 
1991 	if (argc != 1)
1992 		return KDB_ARGCOUNT;
1993 
1994 	nextarg = 1;
1995 	diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL);
1996 	if (diag)
1997 		return diag;
1998 	show_regs((struct pt_regs *)addr);
1999 	return 0;
2000 }
2001 
2002 #if defined(CONFIG_MODULES)
2003 /*
2004  * kdb_lsmod - This function implements the 'lsmod' command.  Lists
2005  *	currently loaded kernel modules.
2006  *	Mostly taken from userland lsmod.
2007  */
2008 static int kdb_lsmod(int argc, const char **argv)
2009 {
2010 	struct module *mod;
2011 
2012 	if (argc != 0)
2013 		return KDB_ARGCOUNT;
2014 
2015 	kdb_printf("Module                  Size  modstruct     Used by\n");
2016 	list_for_each_entry(mod, kdb_modules, list) {
2017 		if (mod->state == MODULE_STATE_UNFORMED)
2018 			continue;
2019 
2020 		kdb_printf("%-20s%8u  0x%px ", mod->name,
2021 			   mod->core_layout.size, (void *)mod);
2022 #ifdef CONFIG_MODULE_UNLOAD
2023 		kdb_printf("%4d ", module_refcount(mod));
2024 #endif
2025 		if (mod->state == MODULE_STATE_GOING)
2026 			kdb_printf(" (Unloading)");
2027 		else if (mod->state == MODULE_STATE_COMING)
2028 			kdb_printf(" (Loading)");
2029 		else
2030 			kdb_printf(" (Live)");
2031 		kdb_printf(" 0x%px", mod->core_layout.base);
2032 
2033 #ifdef CONFIG_MODULE_UNLOAD
2034 		{
2035 			struct module_use *use;
2036 			kdb_printf(" [ ");
2037 			list_for_each_entry(use, &mod->source_list,
2038 					    source_list)
2039 				kdb_printf("%s ", use->target->name);
2040 			kdb_printf("]\n");
2041 		}
2042 #endif
2043 	}
2044 
2045 	return 0;
2046 }
2047 
2048 #endif	/* CONFIG_MODULES */
2049 
2050 /*
2051  * kdb_env - This function implements the 'env' command.  Display the
2052  *	current environment variables.
2053  */
2054 
2055 static int kdb_env(int argc, const char **argv)
2056 {
2057 	kdb_printenv();
2058 
2059 	if (KDB_DEBUG(MASK))
2060 		kdb_printf("KDBDEBUG=0x%x\n",
2061 			(kdb_flags & KDB_DEBUG(MASK)) >> KDB_DEBUG_FLAG_SHIFT);
2062 
2063 	return 0;
2064 }
2065 
2066 #ifdef CONFIG_PRINTK
2067 /*
2068  * kdb_dmesg - This function implements the 'dmesg' command to display
2069  *	the contents of the syslog buffer.
2070  *		dmesg [lines] [adjust]
2071  */
2072 static int kdb_dmesg(int argc, const char **argv)
2073 {
2074 	int diag;
2075 	int logging;
2076 	int lines = 0;
2077 	int adjust = 0;
2078 	int n = 0;
2079 	int skip = 0;
2080 	struct kmsg_dump_iter iter;
2081 	size_t len;
2082 	char buf[201];
2083 
2084 	if (argc > 2)
2085 		return KDB_ARGCOUNT;
2086 	if (argc) {
2087 		char *cp;
2088 		lines = simple_strtol(argv[1], &cp, 0);
2089 		if (*cp)
2090 			lines = 0;
2091 		if (argc > 1) {
2092 			adjust = simple_strtoul(argv[2], &cp, 0);
2093 			if (*cp || adjust < 0)
2094 				adjust = 0;
2095 		}
2096 	}
2097 
2098 	/* disable LOGGING if set */
2099 	diag = kdbgetintenv("LOGGING", &logging);
2100 	if (!diag && logging) {
2101 		const char *setargs[] = { "set", "LOGGING", "0" };
2102 		kdb_set(2, setargs);
2103 	}
2104 
2105 	kmsg_dump_rewind(&iter);
2106 	while (kmsg_dump_get_line(&iter, 1, NULL, 0, NULL))
2107 		n++;
2108 
2109 	if (lines < 0) {
2110 		if (adjust >= n)
2111 			kdb_printf("buffer only contains %d lines, nothing "
2112 				   "printed\n", n);
2113 		else if (adjust - lines >= n)
2114 			kdb_printf("buffer only contains %d lines, last %d "
2115 				   "lines printed\n", n, n - adjust);
2116 		skip = adjust;
2117 		lines = abs(lines);
2118 	} else if (lines > 0) {
2119 		skip = n - lines - adjust;
2120 		lines = abs(lines);
2121 		if (adjust >= n) {
2122 			kdb_printf("buffer only contains %d lines, "
2123 				   "nothing printed\n", n);
2124 			skip = n;
2125 		} else if (skip < 0) {
2126 			lines += skip;
2127 			skip = 0;
2128 			kdb_printf("buffer only contains %d lines, first "
2129 				   "%d lines printed\n", n, lines);
2130 		}
2131 	} else {
2132 		lines = n;
2133 	}
2134 
2135 	if (skip >= n || skip < 0)
2136 		return 0;
2137 
2138 	kmsg_dump_rewind(&iter);
2139 	while (kmsg_dump_get_line(&iter, 1, buf, sizeof(buf), &len)) {
2140 		if (skip) {
2141 			skip--;
2142 			continue;
2143 		}
2144 		if (!lines--)
2145 			break;
2146 		if (KDB_FLAG(CMD_INTERRUPT))
2147 			return 0;
2148 
2149 		kdb_printf("%.*s\n", (int)len - 1, buf);
2150 	}
2151 
2152 	return 0;
2153 }
2154 #endif /* CONFIG_PRINTK */
2155 
2156 /* Make sure we balance enable/disable calls, must disable first. */
2157 static atomic_t kdb_nmi_disabled;
2158 
2159 static int kdb_disable_nmi(int argc, const char *argv[])
2160 {
2161 	if (atomic_read(&kdb_nmi_disabled))
2162 		return 0;
2163 	atomic_set(&kdb_nmi_disabled, 1);
2164 	arch_kgdb_ops.enable_nmi(0);
2165 	return 0;
2166 }
2167 
2168 static int kdb_param_enable_nmi(const char *val, const struct kernel_param *kp)
2169 {
2170 	if (!atomic_add_unless(&kdb_nmi_disabled, -1, 0))
2171 		return -EINVAL;
2172 	arch_kgdb_ops.enable_nmi(1);
2173 	return 0;
2174 }
2175 
2176 static const struct kernel_param_ops kdb_param_ops_enable_nmi = {
2177 	.set = kdb_param_enable_nmi,
2178 };
2179 module_param_cb(enable_nmi, &kdb_param_ops_enable_nmi, NULL, 0600);
2180 
2181 /*
2182  * kdb_cpu - This function implements the 'cpu' command.
2183  *	cpu	[<cpunum>]
2184  * Returns:
2185  *	KDB_CMD_CPU for success, a kdb diagnostic if error
2186  */
2187 static void kdb_cpu_status(void)
2188 {
2189 	int i, start_cpu, first_print = 1;
2190 	char state, prev_state = '?';
2191 
2192 	kdb_printf("Currently on cpu %d\n", raw_smp_processor_id());
2193 	kdb_printf("Available cpus: ");
2194 	for (start_cpu = -1, i = 0; i < NR_CPUS; i++) {
2195 		if (!cpu_online(i)) {
2196 			state = 'F';	/* cpu is offline */
2197 		} else if (!kgdb_info[i].enter_kgdb) {
2198 			state = 'D';	/* cpu is online but unresponsive */
2199 		} else {
2200 			state = ' ';	/* cpu is responding to kdb */
2201 			if (kdb_task_state_char(KDB_TSK(i)) == 'I')
2202 				state = 'I';	/* idle task */
2203 		}
2204 		if (state != prev_state) {
2205 			if (prev_state != '?') {
2206 				if (!first_print)
2207 					kdb_printf(", ");
2208 				first_print = 0;
2209 				kdb_printf("%d", start_cpu);
2210 				if (start_cpu < i-1)
2211 					kdb_printf("-%d", i-1);
2212 				if (prev_state != ' ')
2213 					kdb_printf("(%c)", prev_state);
2214 			}
2215 			prev_state = state;
2216 			start_cpu = i;
2217 		}
2218 	}
2219 	/* print the trailing cpus, ignoring them if they are all offline */
2220 	if (prev_state != 'F') {
2221 		if (!first_print)
2222 			kdb_printf(", ");
2223 		kdb_printf("%d", start_cpu);
2224 		if (start_cpu < i-1)
2225 			kdb_printf("-%d", i-1);
2226 		if (prev_state != ' ')
2227 			kdb_printf("(%c)", prev_state);
2228 	}
2229 	kdb_printf("\n");
2230 }
2231 
2232 static int kdb_cpu(int argc, const char **argv)
2233 {
2234 	unsigned long cpunum;
2235 	int diag;
2236 
2237 	if (argc == 0) {
2238 		kdb_cpu_status();
2239 		return 0;
2240 	}
2241 
2242 	if (argc != 1)
2243 		return KDB_ARGCOUNT;
2244 
2245 	diag = kdbgetularg(argv[1], &cpunum);
2246 	if (diag)
2247 		return diag;
2248 
2249 	/*
2250 	 * Validate cpunum
2251 	 */
2252 	if ((cpunum >= CONFIG_NR_CPUS) || !kgdb_info[cpunum].enter_kgdb)
2253 		return KDB_BADCPUNUM;
2254 
2255 	dbg_switch_cpu = cpunum;
2256 
2257 	/*
2258 	 * Switch to other cpu
2259 	 */
2260 	return KDB_CMD_CPU;
2261 }
2262 
2263 /* The user may not realize that ps/bta with no parameters does not print idle
2264  * or sleeping system daemon processes, so tell them how many were suppressed.
2265  */
2266 void kdb_ps_suppressed(void)
2267 {
2268 	int idle = 0, daemon = 0;
2269 	unsigned long mask_I = kdb_task_state_string("I"),
2270 		      mask_M = kdb_task_state_string("M");
2271 	unsigned long cpu;
2272 	const struct task_struct *p, *g;
2273 	for_each_online_cpu(cpu) {
2274 		p = kdb_curr_task(cpu);
2275 		if (kdb_task_state(p, mask_I))
2276 			++idle;
2277 	}
2278 	for_each_process_thread(g, p) {
2279 		if (kdb_task_state(p, mask_M))
2280 			++daemon;
2281 	}
2282 	if (idle || daemon) {
2283 		if (idle)
2284 			kdb_printf("%d idle process%s (state I)%s\n",
2285 				   idle, idle == 1 ? "" : "es",
2286 				   daemon ? " and " : "");
2287 		if (daemon)
2288 			kdb_printf("%d sleeping system daemon (state M) "
2289 				   "process%s", daemon,
2290 				   daemon == 1 ? "" : "es");
2291 		kdb_printf(" suppressed,\nuse 'ps A' to see all.\n");
2292 	}
2293 }
2294 
2295 /*
2296  * kdb_ps - This function implements the 'ps' command which shows a
2297  *	list of the active processes.
2298  *		ps [DRSTCZEUIMA]   All processes, optionally filtered by state
2299  */
2300 void kdb_ps1(const struct task_struct *p)
2301 {
2302 	int cpu;
2303 	unsigned long tmp;
2304 
2305 	if (!p ||
2306 	    copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
2307 		return;
2308 
2309 	cpu = kdb_process_cpu(p);
2310 	kdb_printf("0x%px %8d %8d  %d %4d   %c  0x%px %c%s\n",
2311 		   (void *)p, p->pid, p->parent->pid,
2312 		   kdb_task_has_cpu(p), kdb_process_cpu(p),
2313 		   kdb_task_state_char(p),
2314 		   (void *)(&p->thread),
2315 		   p == kdb_curr_task(raw_smp_processor_id()) ? '*' : ' ',
2316 		   p->comm);
2317 	if (kdb_task_has_cpu(p)) {
2318 		if (!KDB_TSK(cpu)) {
2319 			kdb_printf("  Error: no saved data for this cpu\n");
2320 		} else {
2321 			if (KDB_TSK(cpu) != p)
2322 				kdb_printf("  Error: does not match running "
2323 				   "process table (0x%px)\n", KDB_TSK(cpu));
2324 		}
2325 	}
2326 }
2327 
2328 static int kdb_ps(int argc, const char **argv)
2329 {
2330 	struct task_struct *g, *p;
2331 	unsigned long mask, cpu;
2332 
2333 	if (argc == 0)
2334 		kdb_ps_suppressed();
2335 	kdb_printf("%-*s      Pid   Parent [*] cpu State %-*s Command\n",
2336 		(int)(2*sizeof(void *))+2, "Task Addr",
2337 		(int)(2*sizeof(void *))+2, "Thread");
2338 	mask = kdb_task_state_string(argc ? argv[1] : NULL);
2339 	/* Run the active tasks first */
2340 	for_each_online_cpu(cpu) {
2341 		if (KDB_FLAG(CMD_INTERRUPT))
2342 			return 0;
2343 		p = kdb_curr_task(cpu);
2344 		if (kdb_task_state(p, mask))
2345 			kdb_ps1(p);
2346 	}
2347 	kdb_printf("\n");
2348 	/* Now the real tasks */
2349 	for_each_process_thread(g, p) {
2350 		if (KDB_FLAG(CMD_INTERRUPT))
2351 			return 0;
2352 		if (kdb_task_state(p, mask))
2353 			kdb_ps1(p);
2354 	}
2355 
2356 	return 0;
2357 }
2358 
2359 /*
2360  * kdb_pid - This function implements the 'pid' command which switches
2361  *	the currently active process.
2362  *		pid [<pid> | R]
2363  */
2364 static int kdb_pid(int argc, const char **argv)
2365 {
2366 	struct task_struct *p;
2367 	unsigned long val;
2368 	int diag;
2369 
2370 	if (argc > 1)
2371 		return KDB_ARGCOUNT;
2372 
2373 	if (argc) {
2374 		if (strcmp(argv[1], "R") == 0) {
2375 			p = KDB_TSK(kdb_initial_cpu);
2376 		} else {
2377 			diag = kdbgetularg(argv[1], &val);
2378 			if (diag)
2379 				return KDB_BADINT;
2380 
2381 			p = find_task_by_pid_ns((pid_t)val,	&init_pid_ns);
2382 			if (!p) {
2383 				kdb_printf("No task with pid=%d\n", (pid_t)val);
2384 				return 0;
2385 			}
2386 		}
2387 		kdb_set_current_task(p);
2388 	}
2389 	kdb_printf("KDB current process is %s(pid=%d)\n",
2390 		   kdb_current_task->comm,
2391 		   kdb_current_task->pid);
2392 
2393 	return 0;
2394 }
2395 
2396 static int kdb_kgdb(int argc, const char **argv)
2397 {
2398 	return KDB_CMD_KGDB;
2399 }
2400 
2401 /*
2402  * kdb_help - This function implements the 'help' and '?' commands.
2403  */
2404 static int kdb_help(int argc, const char **argv)
2405 {
2406 	kdbtab_t *kt;
2407 
2408 	kdb_printf("%-15.15s %-20.20s %s\n", "Command", "Usage", "Description");
2409 	kdb_printf("-----------------------------"
2410 		   "-----------------------------\n");
2411 	list_for_each_entry(kt, &kdb_cmds_head, list_node) {
2412 		char *space = "";
2413 		if (KDB_FLAG(CMD_INTERRUPT))
2414 			return 0;
2415 		if (!kdb_check_flags(kt->cmd_flags, kdb_cmd_enabled, true))
2416 			continue;
2417 		if (strlen(kt->cmd_usage) > 20)
2418 			space = "\n                                    ";
2419 		kdb_printf("%-15.15s %-20s%s%s\n", kt->cmd_name,
2420 			   kt->cmd_usage, space, kt->cmd_help);
2421 	}
2422 	return 0;
2423 }
2424 
2425 /*
2426  * kdb_kill - This function implements the 'kill' commands.
2427  */
2428 static int kdb_kill(int argc, const char **argv)
2429 {
2430 	long sig, pid;
2431 	char *endp;
2432 	struct task_struct *p;
2433 
2434 	if (argc != 2)
2435 		return KDB_ARGCOUNT;
2436 
2437 	sig = simple_strtol(argv[1], &endp, 0);
2438 	if (*endp)
2439 		return KDB_BADINT;
2440 	if ((sig >= 0) || !valid_signal(-sig)) {
2441 		kdb_printf("Invalid signal parameter.<-signal>\n");
2442 		return 0;
2443 	}
2444 	sig = -sig;
2445 
2446 	pid = simple_strtol(argv[2], &endp, 0);
2447 	if (*endp)
2448 		return KDB_BADINT;
2449 	if (pid <= 0) {
2450 		kdb_printf("Process ID must be large than 0.\n");
2451 		return 0;
2452 	}
2453 
2454 	/* Find the process. */
2455 	p = find_task_by_pid_ns(pid, &init_pid_ns);
2456 	if (!p) {
2457 		kdb_printf("The specified process isn't found.\n");
2458 		return 0;
2459 	}
2460 	p = p->group_leader;
2461 	kdb_send_sig(p, sig);
2462 	return 0;
2463 }
2464 
2465 /*
2466  * Most of this code has been lifted from kernel/timer.c::sys_sysinfo().
2467  * I cannot call that code directly from kdb, it has an unconditional
2468  * cli()/sti() and calls routines that take locks which can stop the debugger.
2469  */
2470 static void kdb_sysinfo(struct sysinfo *val)
2471 {
2472 	u64 uptime = ktime_get_mono_fast_ns();
2473 
2474 	memset(val, 0, sizeof(*val));
2475 	val->uptime = div_u64(uptime, NSEC_PER_SEC);
2476 	val->loads[0] = avenrun[0];
2477 	val->loads[1] = avenrun[1];
2478 	val->loads[2] = avenrun[2];
2479 	val->procs = nr_threads-1;
2480 	si_meminfo(val);
2481 
2482 	return;
2483 }
2484 
2485 /*
2486  * kdb_summary - This function implements the 'summary' command.
2487  */
2488 static int kdb_summary(int argc, const char **argv)
2489 {
2490 	time64_t now;
2491 	struct tm tm;
2492 	struct sysinfo val;
2493 
2494 	if (argc)
2495 		return KDB_ARGCOUNT;
2496 
2497 	kdb_printf("sysname    %s\n", init_uts_ns.name.sysname);
2498 	kdb_printf("release    %s\n", init_uts_ns.name.release);
2499 	kdb_printf("version    %s\n", init_uts_ns.name.version);
2500 	kdb_printf("machine    %s\n", init_uts_ns.name.machine);
2501 	kdb_printf("nodename   %s\n", init_uts_ns.name.nodename);
2502 	kdb_printf("domainname %s\n", init_uts_ns.name.domainname);
2503 
2504 	now = __ktime_get_real_seconds();
2505 	time64_to_tm(now, 0, &tm);
2506 	kdb_printf("date       %04ld-%02d-%02d %02d:%02d:%02d "
2507 		   "tz_minuteswest %d\n",
2508 		1900+tm.tm_year, tm.tm_mon+1, tm.tm_mday,
2509 		tm.tm_hour, tm.tm_min, tm.tm_sec,
2510 		sys_tz.tz_minuteswest);
2511 
2512 	kdb_sysinfo(&val);
2513 	kdb_printf("uptime     ");
2514 	if (val.uptime > (24*60*60)) {
2515 		int days = val.uptime / (24*60*60);
2516 		val.uptime %= (24*60*60);
2517 		kdb_printf("%d day%s ", days, days == 1 ? "" : "s");
2518 	}
2519 	kdb_printf("%02ld:%02ld\n", val.uptime/(60*60), (val.uptime/60)%60);
2520 
2521 	kdb_printf("load avg   %ld.%02ld %ld.%02ld %ld.%02ld\n",
2522 		LOAD_INT(val.loads[0]), LOAD_FRAC(val.loads[0]),
2523 		LOAD_INT(val.loads[1]), LOAD_FRAC(val.loads[1]),
2524 		LOAD_INT(val.loads[2]), LOAD_FRAC(val.loads[2]));
2525 
2526 	/* Display in kilobytes */
2527 #define K(x) ((x) << (PAGE_SHIFT - 10))
2528 	kdb_printf("\nMemTotal:       %8lu kB\nMemFree:        %8lu kB\n"
2529 		   "Buffers:        %8lu kB\n",
2530 		   K(val.totalram), K(val.freeram), K(val.bufferram));
2531 	return 0;
2532 }
2533 
2534 /*
2535  * kdb_per_cpu - This function implements the 'per_cpu' command.
2536  */
2537 static int kdb_per_cpu(int argc, const char **argv)
2538 {
2539 	char fmtstr[64];
2540 	int cpu, diag, nextarg = 1;
2541 	unsigned long addr, symaddr, val, bytesperword = 0, whichcpu = ~0UL;
2542 
2543 	if (argc < 1 || argc > 3)
2544 		return KDB_ARGCOUNT;
2545 
2546 	diag = kdbgetaddrarg(argc, argv, &nextarg, &symaddr, NULL, NULL);
2547 	if (diag)
2548 		return diag;
2549 
2550 	if (argc >= 2) {
2551 		diag = kdbgetularg(argv[2], &bytesperword);
2552 		if (diag)
2553 			return diag;
2554 	}
2555 	if (!bytesperword)
2556 		bytesperword = KDB_WORD_SIZE;
2557 	else if (bytesperword > KDB_WORD_SIZE)
2558 		return KDB_BADWIDTH;
2559 	sprintf(fmtstr, "%%0%dlx ", (int)(2*bytesperword));
2560 	if (argc >= 3) {
2561 		diag = kdbgetularg(argv[3], &whichcpu);
2562 		if (diag)
2563 			return diag;
2564 		if (whichcpu >= nr_cpu_ids || !cpu_online(whichcpu)) {
2565 			kdb_printf("cpu %ld is not online\n", whichcpu);
2566 			return KDB_BADCPUNUM;
2567 		}
2568 	}
2569 
2570 	/* Most architectures use __per_cpu_offset[cpu], some use
2571 	 * __per_cpu_offset(cpu), smp has no __per_cpu_offset.
2572 	 */
2573 #ifdef	__per_cpu_offset
2574 #define KDB_PCU(cpu) __per_cpu_offset(cpu)
2575 #else
2576 #ifdef	CONFIG_SMP
2577 #define KDB_PCU(cpu) __per_cpu_offset[cpu]
2578 #else
2579 #define KDB_PCU(cpu) 0
2580 #endif
2581 #endif
2582 	for_each_online_cpu(cpu) {
2583 		if (KDB_FLAG(CMD_INTERRUPT))
2584 			return 0;
2585 
2586 		if (whichcpu != ~0UL && whichcpu != cpu)
2587 			continue;
2588 		addr = symaddr + KDB_PCU(cpu);
2589 		diag = kdb_getword(&val, addr, bytesperword);
2590 		if (diag) {
2591 			kdb_printf("%5d " kdb_bfd_vma_fmt0 " - unable to "
2592 				   "read, diag=%d\n", cpu, addr, diag);
2593 			continue;
2594 		}
2595 		kdb_printf("%5d ", cpu);
2596 		kdb_md_line(fmtstr, addr,
2597 			bytesperword == KDB_WORD_SIZE,
2598 			1, bytesperword, 1, 1, 0);
2599 	}
2600 #undef KDB_PCU
2601 	return 0;
2602 }
2603 
2604 /*
2605  * display help for the use of cmd | grep pattern
2606  */
2607 static int kdb_grep_help(int argc, const char **argv)
2608 {
2609 	kdb_printf("Usage of  cmd args | grep pattern:\n");
2610 	kdb_printf("  Any command's output may be filtered through an ");
2611 	kdb_printf("emulated 'pipe'.\n");
2612 	kdb_printf("  'grep' is just a key word.\n");
2613 	kdb_printf("  The pattern may include a very limited set of "
2614 		   "metacharacters:\n");
2615 	kdb_printf("   pattern or ^pattern or pattern$ or ^pattern$\n");
2616 	kdb_printf("  And if there are spaces in the pattern, you may "
2617 		   "quote it:\n");
2618 	kdb_printf("   \"pat tern\" or \"^pat tern\" or \"pat tern$\""
2619 		   " or \"^pat tern$\"\n");
2620 	return 0;
2621 }
2622 
2623 /*
2624  * kdb_register_flags - This function is used to register a kernel
2625  * 	debugger command.
2626  * Inputs:
2627  *	cmd	Command name
2628  *	func	Function to execute the command
2629  *	usage	A simple usage string showing arguments
2630  *	help	A simple help string describing command
2631  *	repeat	Does the command auto repeat on enter?
2632  * Returns:
2633  *	zero for success, one if a duplicate command.
2634  */
2635 int kdb_register_flags(char *cmd,
2636 		       kdb_func_t func,
2637 		       char *usage,
2638 		       char *help,
2639 		       short minlen,
2640 		       kdb_cmdflags_t flags)
2641 {
2642 	kdbtab_t *kp;
2643 
2644 	list_for_each_entry(kp, &kdb_cmds_head, list_node) {
2645 		if (strcmp(kp->cmd_name, cmd) == 0) {
2646 			kdb_printf("Duplicate kdb command registered: "
2647 				"%s, func %px help %s\n", cmd, func, help);
2648 			return 1;
2649 		}
2650 	}
2651 
2652 	kp = kmalloc(sizeof(*kp), GFP_KDB);
2653 	if (!kp) {
2654 		kdb_printf("Could not allocate new kdb_command table\n");
2655 		return 1;
2656 	}
2657 
2658 	kp->cmd_name   = cmd;
2659 	kp->cmd_func   = func;
2660 	kp->cmd_usage  = usage;
2661 	kp->cmd_help   = help;
2662 	kp->cmd_minlen = minlen;
2663 	kp->cmd_flags  = flags;
2664 	kp->is_dynamic = true;
2665 
2666 	list_add_tail(&kp->list_node, &kdb_cmds_head);
2667 
2668 	return 0;
2669 }
2670 EXPORT_SYMBOL_GPL(kdb_register_flags);
2671 
2672 /*
2673  * kdb_register_table() - This function is used to register a kdb command
2674  *                        table.
2675  * @kp: pointer to kdb command table
2676  * @len: length of kdb command table
2677  */
2678 void kdb_register_table(kdbtab_t *kp, size_t len)
2679 {
2680 	while (len--) {
2681 		list_add_tail(&kp->list_node, &kdb_cmds_head);
2682 		kp++;
2683 	}
2684 }
2685 
2686 /*
2687  * kdb_register - Compatibility register function for commands that do
2688  *	not need to specify a repeat state.  Equivalent to
2689  *	kdb_register_flags with flags set to 0.
2690  * Inputs:
2691  *	cmd	Command name
2692  *	func	Function to execute the command
2693  *	usage	A simple usage string showing arguments
2694  *	help	A simple help string describing command
2695  * Returns:
2696  *	zero for success, one if a duplicate command.
2697  */
2698 int kdb_register(char *cmd,
2699 	     kdb_func_t func,
2700 	     char *usage,
2701 	     char *help,
2702 	     short minlen)
2703 {
2704 	return kdb_register_flags(cmd, func, usage, help, minlen, 0);
2705 }
2706 EXPORT_SYMBOL_GPL(kdb_register);
2707 
2708 /*
2709  * kdb_unregister - This function is used to unregister a kernel
2710  *	debugger command.  It is generally called when a module which
2711  *	implements kdb commands is unloaded.
2712  * Inputs:
2713  *	cmd	Command name
2714  * Returns:
2715  *	zero for success, one command not registered.
2716  */
2717 int kdb_unregister(char *cmd)
2718 {
2719 	kdbtab_t *kp;
2720 
2721 	/*
2722 	 *  find the command.
2723 	 */
2724 	list_for_each_entry(kp, &kdb_cmds_head, list_node) {
2725 		if (strcmp(kp->cmd_name, cmd) == 0) {
2726 			list_del(&kp->list_node);
2727 			if (kp->is_dynamic)
2728 				kfree(kp);
2729 			return 0;
2730 		}
2731 	}
2732 
2733 	/* Couldn't find it.  */
2734 	return 1;
2735 }
2736 EXPORT_SYMBOL_GPL(kdb_unregister);
2737 
2738 static kdbtab_t maintab[] = {
2739 	{	.cmd_name = "md",
2740 		.cmd_func = kdb_md,
2741 		.cmd_usage = "<vaddr>",
2742 		.cmd_help = "Display Memory Contents, also mdWcN, e.g. md8c1",
2743 		.cmd_minlen = 1,
2744 		.cmd_flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
2745 	},
2746 	{	.cmd_name = "mdr",
2747 		.cmd_func = kdb_md,
2748 		.cmd_usage = "<vaddr> <bytes>",
2749 		.cmd_help = "Display Raw Memory",
2750 		.cmd_flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
2751 	},
2752 	{	.cmd_name = "mdp",
2753 		.cmd_func = kdb_md,
2754 		.cmd_usage = "<paddr> <bytes>",
2755 		.cmd_help = "Display Physical Memory",
2756 		.cmd_flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
2757 	},
2758 	{	.cmd_name = "mds",
2759 		.cmd_func = kdb_md,
2760 		.cmd_usage = "<vaddr>",
2761 		.cmd_help = "Display Memory Symbolically",
2762 		.cmd_flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
2763 	},
2764 	{	.cmd_name = "mm",
2765 		.cmd_func = kdb_mm,
2766 		.cmd_usage = "<vaddr> <contents>",
2767 		.cmd_help = "Modify Memory Contents",
2768 		.cmd_flags = KDB_ENABLE_MEM_WRITE | KDB_REPEAT_NO_ARGS,
2769 	},
2770 	{	.cmd_name = "go",
2771 		.cmd_func = kdb_go,
2772 		.cmd_usage = "[<vaddr>]",
2773 		.cmd_help = "Continue Execution",
2774 		.cmd_minlen = 1,
2775 		.cmd_flags = KDB_ENABLE_REG_WRITE |
2776 			     KDB_ENABLE_ALWAYS_SAFE_NO_ARGS,
2777 	},
2778 	{	.cmd_name = "rd",
2779 		.cmd_func = kdb_rd,
2780 		.cmd_usage = "",
2781 		.cmd_help = "Display Registers",
2782 		.cmd_flags = KDB_ENABLE_REG_READ,
2783 	},
2784 	{	.cmd_name = "rm",
2785 		.cmd_func = kdb_rm,
2786 		.cmd_usage = "<reg> <contents>",
2787 		.cmd_help = "Modify Registers",
2788 		.cmd_flags = KDB_ENABLE_REG_WRITE,
2789 	},
2790 	{	.cmd_name = "ef",
2791 		.cmd_func = kdb_ef,
2792 		.cmd_usage = "<vaddr>",
2793 		.cmd_help = "Display exception frame",
2794 		.cmd_flags = KDB_ENABLE_MEM_READ,
2795 	},
2796 	{	.cmd_name = "bt",
2797 		.cmd_func = kdb_bt,
2798 		.cmd_usage = "[<vaddr>]",
2799 		.cmd_help = "Stack traceback",
2800 		.cmd_minlen = 1,
2801 		.cmd_flags = KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS,
2802 	},
2803 	{	.cmd_name = "btp",
2804 		.cmd_func = kdb_bt,
2805 		.cmd_usage = "<pid>",
2806 		.cmd_help = "Display stack for process <pid>",
2807 		.cmd_flags = KDB_ENABLE_INSPECT,
2808 	},
2809 	{	.cmd_name = "bta",
2810 		.cmd_func = kdb_bt,
2811 		.cmd_usage = "[D|R|S|T|C|Z|E|U|I|M|A]",
2812 		.cmd_help = "Backtrace all processes matching state flag",
2813 		.cmd_flags = KDB_ENABLE_INSPECT,
2814 	},
2815 	{	.cmd_name = "btc",
2816 		.cmd_func = kdb_bt,
2817 		.cmd_usage = "",
2818 		.cmd_help = "Backtrace current process on each cpu",
2819 		.cmd_flags = KDB_ENABLE_INSPECT,
2820 	},
2821 	{	.cmd_name = "btt",
2822 		.cmd_func = kdb_bt,
2823 		.cmd_usage = "<vaddr>",
2824 		.cmd_help = "Backtrace process given its struct task address",
2825 		.cmd_flags = KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS,
2826 	},
2827 	{	.cmd_name = "env",
2828 		.cmd_func = kdb_env,
2829 		.cmd_usage = "",
2830 		.cmd_help = "Show environment variables",
2831 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2832 	},
2833 	{	.cmd_name = "set",
2834 		.cmd_func = kdb_set,
2835 		.cmd_usage = "",
2836 		.cmd_help = "Set environment variables",
2837 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2838 	},
2839 	{	.cmd_name = "help",
2840 		.cmd_func = kdb_help,
2841 		.cmd_usage = "",
2842 		.cmd_help = "Display Help Message",
2843 		.cmd_minlen = 1,
2844 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2845 	},
2846 	{	.cmd_name = "?",
2847 		.cmd_func = kdb_help,
2848 		.cmd_usage = "",
2849 		.cmd_help = "Display Help Message",
2850 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2851 	},
2852 	{	.cmd_name = "cpu",
2853 		.cmd_func = kdb_cpu,
2854 		.cmd_usage = "<cpunum>",
2855 		.cmd_help = "Switch to new cpu",
2856 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE_NO_ARGS,
2857 	},
2858 	{	.cmd_name = "kgdb",
2859 		.cmd_func = kdb_kgdb,
2860 		.cmd_usage = "",
2861 		.cmd_help = "Enter kgdb mode",
2862 		.cmd_flags = 0,
2863 	},
2864 	{	.cmd_name = "ps",
2865 		.cmd_func = kdb_ps,
2866 		.cmd_usage = "[<flags>|A]",
2867 		.cmd_help = "Display active task list",
2868 		.cmd_flags = KDB_ENABLE_INSPECT,
2869 	},
2870 	{	.cmd_name = "pid",
2871 		.cmd_func = kdb_pid,
2872 		.cmd_usage = "<pidnum>",
2873 		.cmd_help = "Switch to another task",
2874 		.cmd_flags = KDB_ENABLE_INSPECT,
2875 	},
2876 	{	.cmd_name = "reboot",
2877 		.cmd_func = kdb_reboot,
2878 		.cmd_usage = "",
2879 		.cmd_help = "Reboot the machine immediately",
2880 		.cmd_flags = KDB_ENABLE_REBOOT,
2881 	},
2882 #if defined(CONFIG_MODULES)
2883 	{	.cmd_name = "lsmod",
2884 		.cmd_func = kdb_lsmod,
2885 		.cmd_usage = "",
2886 		.cmd_help = "List loaded kernel modules",
2887 		.cmd_flags = KDB_ENABLE_INSPECT,
2888 	},
2889 #endif
2890 #if defined(CONFIG_MAGIC_SYSRQ)
2891 	{	.cmd_name = "sr",
2892 		.cmd_func = kdb_sr,
2893 		.cmd_usage = "<key>",
2894 		.cmd_help = "Magic SysRq key",
2895 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2896 	},
2897 #endif
2898 #if defined(CONFIG_PRINTK)
2899 	{	.cmd_name = "dmesg",
2900 		.cmd_func = kdb_dmesg,
2901 		.cmd_usage = "[lines]",
2902 		.cmd_help = "Display syslog buffer",
2903 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2904 	},
2905 #endif
2906 	{	.cmd_name = "defcmd",
2907 		.cmd_func = kdb_defcmd,
2908 		.cmd_usage = "name \"usage\" \"help\"",
2909 		.cmd_help = "Define a set of commands, down to endefcmd",
2910 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2911 	},
2912 	{	.cmd_name = "kill",
2913 		.cmd_func = kdb_kill,
2914 		.cmd_usage = "<-signal> <pid>",
2915 		.cmd_help = "Send a signal to a process",
2916 		.cmd_flags = KDB_ENABLE_SIGNAL,
2917 	},
2918 	{	.cmd_name = "summary",
2919 		.cmd_func = kdb_summary,
2920 		.cmd_usage = "",
2921 		.cmd_help = "Summarize the system",
2922 		.cmd_minlen = 4,
2923 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2924 	},
2925 	{	.cmd_name = "per_cpu",
2926 		.cmd_func = kdb_per_cpu,
2927 		.cmd_usage = "<sym> [<bytes>] [<cpu>]",
2928 		.cmd_help = "Display per_cpu variables",
2929 		.cmd_minlen = 3,
2930 		.cmd_flags = KDB_ENABLE_MEM_READ,
2931 	},
2932 	{	.cmd_name = "grephelp",
2933 		.cmd_func = kdb_grep_help,
2934 		.cmd_usage = "",
2935 		.cmd_help = "Display help on | grep",
2936 		.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2937 	},
2938 };
2939 
2940 static kdbtab_t nmicmd = {
2941 	.cmd_name = "disable_nmi",
2942 	.cmd_func = kdb_disable_nmi,
2943 	.cmd_usage = "",
2944 	.cmd_help = "Disable NMI entry to KDB",
2945 	.cmd_flags = KDB_ENABLE_ALWAYS_SAFE,
2946 };
2947 
2948 /* Initialize the kdb command table. */
2949 static void __init kdb_inittab(void)
2950 {
2951 	kdb_register_table(maintab, ARRAY_SIZE(maintab));
2952 	if (arch_kgdb_ops.enable_nmi)
2953 		kdb_register_table(&nmicmd, 1);
2954 }
2955 
2956 /* Execute any commands defined in kdb_cmds.  */
2957 static void __init kdb_cmd_init(void)
2958 {
2959 	int i, diag;
2960 	for (i = 0; kdb_cmds[i]; ++i) {
2961 		diag = kdb_parse(kdb_cmds[i]);
2962 		if (diag)
2963 			kdb_printf("kdb command %s failed, kdb diag %d\n",
2964 				kdb_cmds[i], diag);
2965 	}
2966 	if (defcmd_in_progress) {
2967 		kdb_printf("Incomplete 'defcmd' set, forcing endefcmd\n");
2968 		kdb_parse("endefcmd");
2969 	}
2970 }
2971 
2972 /* Initialize kdb_printf, breakpoint tables and kdb state */
2973 void __init kdb_init(int lvl)
2974 {
2975 	static int kdb_init_lvl = KDB_NOT_INITIALIZED;
2976 	int i;
2977 
2978 	if (kdb_init_lvl == KDB_INIT_FULL || lvl <= kdb_init_lvl)
2979 		return;
2980 	for (i = kdb_init_lvl; i < lvl; i++) {
2981 		switch (i) {
2982 		case KDB_NOT_INITIALIZED:
2983 			kdb_inittab();		/* Initialize Command Table */
2984 			kdb_initbptab();	/* Initialize Breakpoints */
2985 			break;
2986 		case KDB_INIT_EARLY:
2987 			kdb_cmd_init();		/* Build kdb_cmds tables */
2988 			break;
2989 		}
2990 	}
2991 	kdb_init_lvl = lvl;
2992 }
2993