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1/*
2 * Kernel Debugger Architecture Independent Support Functions
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) 2009 Wind River Systems, Inc. All Rights Reserved.
10 * 03/02/13 added new 2.5 kallsyms <xavier.bru@bull.net>
11 */
12
13#include <stdarg.h>
14#include <linux/types.h>
15#include <linux/sched.h>
16#include <linux/mm.h>
17#include <linux/kallsyms.h>
18#include <linux/stddef.h>
19#include <linux/vmalloc.h>
20#include <linux/ptrace.h>
21#include <linux/module.h>
22#include <linux/highmem.h>
23#include <linux/hardirq.h>
24#include <linux/delay.h>
25#include <linux/uaccess.h>
26#include <linux/kdb.h>
27#include <linux/slab.h>
28#include "kdb_private.h"
29
30/*
31 * kdbgetsymval - Return the address of the given symbol.
32 *
33 * Parameters:
34 * symname Character string containing symbol name
35 * symtab Structure to receive results
36 * Returns:
37 * 0 Symbol not found, symtab zero filled
38 * 1 Symbol mapped to module/symbol/section, data in symtab
39 */
40int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
41{
42 if (KDB_DEBUG(AR))
43 kdb_printf("kdbgetsymval: symname=%s, symtab=%p\n", symname,
44 symtab);
45 memset(symtab, 0, sizeof(*symtab));
46 symtab->sym_start = kallsyms_lookup_name(symname);
47 if (symtab->sym_start) {
48 if (KDB_DEBUG(AR))
49 kdb_printf("kdbgetsymval: returns 1, "
50 "symtab->sym_start=0x%lx\n",
51 symtab->sym_start);
52 return 1;
53 }
54 if (KDB_DEBUG(AR))
55 kdb_printf("kdbgetsymval: returns 0\n");
56 return 0;
57}
58EXPORT_SYMBOL(kdbgetsymval);
59
60static char *kdb_name_table[100]; /* arbitrary size */
61
62/*
63 * kdbnearsym - Return the name of the symbol with the nearest address
64 * less than 'addr'.
65 *
66 * Parameters:
67 * addr Address to check for symbol near
68 * symtab Structure to receive results
69 * Returns:
70 * 0 No sections contain this address, symtab zero filled
71 * 1 Address mapped to module/symbol/section, data in symtab
72 * Remarks:
73 * 2.6 kallsyms has a "feature" where it unpacks the name into a
74 * string. If that string is reused before the caller expects it
75 * then the caller sees its string change without warning. To
76 * avoid cluttering up the main kdb code with lots of kdb_strdup,
77 * tests and kfree calls, kdbnearsym maintains an LRU list of the
78 * last few unique strings. The list is sized large enough to
79 * hold active strings, no kdb caller of kdbnearsym makes more
80 * than ~20 later calls before using a saved value.
81 */
82int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
83{
84 int ret = 0;
85 unsigned long symbolsize = 0;
86 unsigned long offset = 0;
87#define knt1_size 128 /* must be >= kallsyms table size */
88 char *knt1 = NULL;
89
90 if (KDB_DEBUG(AR))
91 kdb_printf("kdbnearsym: addr=0x%lx, symtab=%p\n", addr, symtab);
92 memset(symtab, 0, sizeof(*symtab));
93
94 if (addr < 4096)
95 goto out;
96 knt1 = debug_kmalloc(knt1_size, GFP_ATOMIC);
97 if (!knt1) {
98 kdb_printf("kdbnearsym: addr=0x%lx cannot kmalloc knt1\n",
99 addr);
100 goto out;
101 }
102 symtab->sym_name = kallsyms_lookup(addr, &symbolsize , &offset,
103 (char **)(&symtab->mod_name), knt1);
104 if (offset > 8*1024*1024) {
105 symtab->sym_name = NULL;
106 addr = offset = symbolsize = 0;
107 }
108 symtab->sym_start = addr - offset;
109 symtab->sym_end = symtab->sym_start + symbolsize;
110 ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0';
111
112 if (ret) {
113 int i;
114 /* Another 2.6 kallsyms "feature". Sometimes the sym_name is
115 * set but the buffer passed into kallsyms_lookup is not used,
116 * so it contains garbage. The caller has to work out which
117 * buffer needs to be saved.
118 *
119 * What was Rusty smoking when he wrote that code?
120 */
121 if (symtab->sym_name != knt1) {
122 strncpy(knt1, symtab->sym_name, knt1_size);
123 knt1[knt1_size-1] = '\0';
124 }
125 for (i = 0; i < ARRAY_SIZE(kdb_name_table); ++i) {
126 if (kdb_name_table[i] &&
127 strcmp(kdb_name_table[i], knt1) == 0)
128 break;
129 }
130 if (i >= ARRAY_SIZE(kdb_name_table)) {
131 debug_kfree(kdb_name_table[0]);
132 memcpy(kdb_name_table, kdb_name_table+1,
133 sizeof(kdb_name_table[0]) *
134 (ARRAY_SIZE(kdb_name_table)-1));
135 } else {
136 debug_kfree(knt1);
137 knt1 = kdb_name_table[i];
138 memcpy(kdb_name_table+i, kdb_name_table+i+1,
139 sizeof(kdb_name_table[0]) *
140 (ARRAY_SIZE(kdb_name_table)-i-1));
141 }
142 i = ARRAY_SIZE(kdb_name_table) - 1;
143 kdb_name_table[i] = knt1;
144 symtab->sym_name = kdb_name_table[i];
145 knt1 = NULL;
146 }
147
148 if (symtab->mod_name == NULL)
149 symtab->mod_name = "kernel";
150 if (KDB_DEBUG(AR))
151 kdb_printf("kdbnearsym: returns %d symtab->sym_start=0x%lx, "
152 "symtab->mod_name=%p, symtab->sym_name=%p (%s)\n", ret,
153 symtab->sym_start, symtab->mod_name, symtab->sym_name,
154 symtab->sym_name);
155
156out:
157 debug_kfree(knt1);
158 return ret;
159}
160
161void kdbnearsym_cleanup(void)
162{
163 int i;
164 for (i = 0; i < ARRAY_SIZE(kdb_name_table); ++i) {
165 if (kdb_name_table[i]) {
166 debug_kfree(kdb_name_table[i]);
167 kdb_name_table[i] = NULL;
168 }
169 }
170}
171
172static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1];
173
174/*
175 * kallsyms_symbol_complete
176 *
177 * Parameters:
178 * prefix_name prefix of a symbol name to lookup
179 * max_len maximum length that can be returned
180 * Returns:
181 * Number of symbols which match the given prefix.
182 * Notes:
183 * prefix_name is changed to contain the longest unique prefix that
184 * starts with this prefix (tab completion).
185 */
186int kallsyms_symbol_complete(char *prefix_name, int max_len)
187{
188 loff_t pos = 0;
189 int prefix_len = strlen(prefix_name), prev_len = 0;
190 int i, number = 0;
191 const char *name;
192
193 while ((name = kdb_walk_kallsyms(&pos))) {
194 if (strncmp(name, prefix_name, prefix_len) == 0) {
195 strcpy(ks_namebuf, name);
196 /* Work out the longest name that matches the prefix */
197 if (++number == 1) {
198 prev_len = min_t(int, max_len-1,
199 strlen(ks_namebuf));
200 memcpy(ks_namebuf_prev, ks_namebuf, prev_len);
201 ks_namebuf_prev[prev_len] = '\0';
202 continue;
203 }
204 for (i = 0; i < prev_len; i++) {
205 if (ks_namebuf[i] != ks_namebuf_prev[i]) {
206 prev_len = i;
207 ks_namebuf_prev[i] = '\0';
208 break;
209 }
210 }
211 }
212 }
213 if (prev_len > prefix_len)
214 memcpy(prefix_name, ks_namebuf_prev, prev_len+1);
215 return number;
216}
217
218/*
219 * kallsyms_symbol_next
220 *
221 * Parameters:
222 * prefix_name prefix of a symbol name to lookup
223 * flag 0 means search from the head, 1 means continue search.
224 * Returns:
225 * 1 if a symbol matches the given prefix.
226 * 0 if no string found
227 */
228int kallsyms_symbol_next(char *prefix_name, int flag)
229{
230 int prefix_len = strlen(prefix_name);
231 static loff_t pos;
232 const char *name;
233
234 if (!flag)
235 pos = 0;
236
237 while ((name = kdb_walk_kallsyms(&pos))) {
238 if (strncmp(name, prefix_name, prefix_len) == 0) {
239 strncpy(prefix_name, name, strlen(name)+1);
240 return 1;
241 }
242 }
243 return 0;
244}
245
246/*
247 * kdb_symbol_print - Standard method for printing a symbol name and offset.
248 * Inputs:
249 * addr Address to be printed.
250 * symtab Address of symbol data, if NULL this routine does its
251 * own lookup.
252 * punc Punctuation for string, bit field.
253 * Remarks:
254 * The string and its punctuation is only printed if the address
255 * is inside the kernel, except that the value is always printed
256 * when requested.
257 */
258void kdb_symbol_print(unsigned long addr, const kdb_symtab_t *symtab_p,
259 unsigned int punc)
260{
261 kdb_symtab_t symtab, *symtab_p2;
262 if (symtab_p) {
263 symtab_p2 = (kdb_symtab_t *)symtab_p;
264 } else {
265 symtab_p2 = &symtab;
266 kdbnearsym(addr, symtab_p2);
267 }
268 if (!(symtab_p2->sym_name || (punc & KDB_SP_VALUE)))
269 return;
270 if (punc & KDB_SP_SPACEB)
271 kdb_printf(" ");
272 if (punc & KDB_SP_VALUE)
273 kdb_printf(kdb_machreg_fmt0, addr);
274 if (symtab_p2->sym_name) {
275 if (punc & KDB_SP_VALUE)
276 kdb_printf(" ");
277 if (punc & KDB_SP_PAREN)
278 kdb_printf("(");
279 if (strcmp(symtab_p2->mod_name, "kernel"))
280 kdb_printf("[%s]", symtab_p2->mod_name);
281 kdb_printf("%s", symtab_p2->sym_name);
282 if (addr != symtab_p2->sym_start)
283 kdb_printf("+0x%lx", addr - symtab_p2->sym_start);
284 if (punc & KDB_SP_SYMSIZE)
285 kdb_printf("/0x%lx",
286 symtab_p2->sym_end - symtab_p2->sym_start);
287 if (punc & KDB_SP_PAREN)
288 kdb_printf(")");
289 }
290 if (punc & KDB_SP_SPACEA)
291 kdb_printf(" ");
292 if (punc & KDB_SP_NEWLINE)
293 kdb_printf("\n");
294}
295
296/*
297 * kdb_strdup - kdb equivalent of strdup, for disasm code.
298 * Inputs:
299 * str The string to duplicate.
300 * type Flags to kmalloc for the new string.
301 * Returns:
302 * Address of the new string, NULL if storage could not be allocated.
303 * Remarks:
304 * This is not in lib/string.c because it uses kmalloc which is not
305 * available when string.o is used in boot loaders.
306 */
307char *kdb_strdup(const char *str, gfp_t type)
308{
309 int n = strlen(str)+1;
310 char *s = kmalloc(n, type);
311 if (!s)
312 return NULL;
313 return strcpy(s, str);
314}
315
316/*
317 * kdb_getarea_size - Read an area of data. The kdb equivalent of
318 * copy_from_user, with kdb messages for invalid addresses.
319 * Inputs:
320 * res Pointer to the area to receive the result.
321 * addr Address of the area to copy.
322 * size Size of the area.
323 * Returns:
324 * 0 for success, < 0 for error.
325 */
326int kdb_getarea_size(void *res, unsigned long addr, size_t size)
327{
328 int ret = probe_kernel_read((char *)res, (char *)addr, size);
329 if (ret) {
330 if (!KDB_STATE(SUPPRESS)) {
331 kdb_printf("kdb_getarea: Bad address 0x%lx\n", addr);
332 KDB_STATE_SET(SUPPRESS);
333 }
334 ret = KDB_BADADDR;
335 } else {
336 KDB_STATE_CLEAR(SUPPRESS);
337 }
338 return ret;
339}
340
341/*
342 * kdb_putarea_size - Write an area of data. The kdb equivalent of
343 * copy_to_user, with kdb messages for invalid addresses.
344 * Inputs:
345 * addr Address of the area to write to.
346 * res Pointer to the area holding the data.
347 * size Size of the area.
348 * Returns:
349 * 0 for success, < 0 for error.
350 */
351int kdb_putarea_size(unsigned long addr, void *res, size_t size)
352{
353 int ret = probe_kernel_read((char *)addr, (char *)res, size);
354 if (ret) {
355 if (!KDB_STATE(SUPPRESS)) {
356 kdb_printf("kdb_putarea: Bad address 0x%lx\n", addr);
357 KDB_STATE_SET(SUPPRESS);
358 }
359 ret = KDB_BADADDR;
360 } else {
361 KDB_STATE_CLEAR(SUPPRESS);
362 }
363 return ret;
364}
365
366/*
367 * kdb_getphys - Read data from a physical address. Validate the
368 * address is in range, use kmap_atomic() to get data
369 * similar to kdb_getarea() - but for phys addresses
370 * Inputs:
371 * res Pointer to the word to receive the result
372 * addr Physical address of the area to copy
373 * size Size of the area
374 * Returns:
375 * 0 for success, < 0 for error.
376 */
377static int kdb_getphys(void *res, unsigned long addr, size_t size)
378{
379 unsigned long pfn;
380 void *vaddr;
381 struct page *page;
382
383 pfn = (addr >> PAGE_SHIFT);
384 if (!pfn_valid(pfn))
385 return 1;
386 page = pfn_to_page(pfn);
387 vaddr = kmap_atomic(page);
388 memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size);
389 kunmap_atomic(vaddr);
390
391 return 0;
392}
393
394/*
395 * kdb_getphysword
396 * Inputs:
397 * word Pointer to the word to receive the result.
398 * addr Address of the area to copy.
399 * size Size of the area.
400 * Returns:
401 * 0 for success, < 0 for error.
402 */
403int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
404{
405 int diag;
406 __u8 w1;
407 __u16 w2;
408 __u32 w4;
409 __u64 w8;
410 *word = 0; /* Default value if addr or size is invalid */
411
412 switch (size) {
413 case 1:
414 diag = kdb_getphys(&w1, addr, sizeof(w1));
415 if (!diag)
416 *word = w1;
417 break;
418 case 2:
419 diag = kdb_getphys(&w2, addr, sizeof(w2));
420 if (!diag)
421 *word = w2;
422 break;
423 case 4:
424 diag = kdb_getphys(&w4, addr, sizeof(w4));
425 if (!diag)
426 *word = w4;
427 break;
428 case 8:
429 if (size <= sizeof(*word)) {
430 diag = kdb_getphys(&w8, addr, sizeof(w8));
431 if (!diag)
432 *word = w8;
433 break;
434 }
435 /* drop through */
436 default:
437 diag = KDB_BADWIDTH;
438 kdb_printf("kdb_getphysword: bad width %ld\n", (long) size);
439 }
440 return diag;
441}
442
443/*
444 * kdb_getword - Read a binary value. Unlike kdb_getarea, this treats
445 * data as numbers.
446 * Inputs:
447 * word Pointer to the word to receive the result.
448 * addr Address of the area to copy.
449 * size Size of the area.
450 * Returns:
451 * 0 for success, < 0 for error.
452 */
453int kdb_getword(unsigned long *word, unsigned long addr, size_t size)
454{
455 int diag;
456 __u8 w1;
457 __u16 w2;
458 __u32 w4;
459 __u64 w8;
460 *word = 0; /* Default value if addr or size is invalid */
461 switch (size) {
462 case 1:
463 diag = kdb_getarea(w1, addr);
464 if (!diag)
465 *word = w1;
466 break;
467 case 2:
468 diag = kdb_getarea(w2, addr);
469 if (!diag)
470 *word = w2;
471 break;
472 case 4:
473 diag = kdb_getarea(w4, addr);
474 if (!diag)
475 *word = w4;
476 break;
477 case 8:
478 if (size <= sizeof(*word)) {
479 diag = kdb_getarea(w8, addr);
480 if (!diag)
481 *word = w8;
482 break;
483 }
484 /* drop through */
485 default:
486 diag = KDB_BADWIDTH;
487 kdb_printf("kdb_getword: bad width %ld\n", (long) size);
488 }
489 return diag;
490}
491
492/*
493 * kdb_putword - Write a binary value. Unlike kdb_putarea, this
494 * treats data as numbers.
495 * Inputs:
496 * addr Address of the area to write to..
497 * word The value to set.
498 * size Size of the area.
499 * Returns:
500 * 0 for success, < 0 for error.
501 */
502int kdb_putword(unsigned long addr, unsigned long word, size_t size)
503{
504 int diag;
505 __u8 w1;
506 __u16 w2;
507 __u32 w4;
508 __u64 w8;
509 switch (size) {
510 case 1:
511 w1 = word;
512 diag = kdb_putarea(addr, w1);
513 break;
514 case 2:
515 w2 = word;
516 diag = kdb_putarea(addr, w2);
517 break;
518 case 4:
519 w4 = word;
520 diag = kdb_putarea(addr, w4);
521 break;
522 case 8:
523 if (size <= sizeof(word)) {
524 w8 = word;
525 diag = kdb_putarea(addr, w8);
526 break;
527 }
528 /* drop through */
529 default:
530 diag = KDB_BADWIDTH;
531 kdb_printf("kdb_putword: bad width %ld\n", (long) size);
532 }
533 return diag;
534}
535
536/*
537 * kdb_task_state_string - Convert a string containing any of the
538 * letters DRSTCZEUIMA to a mask for the process state field and
539 * return the value. If no argument is supplied, return the mask
540 * that corresponds to environment variable PS, DRSTCZEU by
541 * default.
542 * Inputs:
543 * s String to convert
544 * Returns:
545 * Mask for process state.
546 * Notes:
547 * The mask folds data from several sources into a single long value, so
548 * be careful not to overlap the bits. TASK_* bits are in the LSB,
549 * special cases like UNRUNNABLE are in the MSB. As of 2.6.10-rc1 there
550 * is no overlap between TASK_* and EXIT_* but that may not always be
551 * true, so EXIT_* bits are shifted left 16 bits before being stored in
552 * the mask.
553 */
554
555/* unrunnable is < 0 */
556#define UNRUNNABLE (1UL << (8*sizeof(unsigned long) - 1))
557#define RUNNING (1UL << (8*sizeof(unsigned long) - 2))
558#define IDLE (1UL << (8*sizeof(unsigned long) - 3))
559#define DAEMON (1UL << (8*sizeof(unsigned long) - 4))
560
561unsigned long kdb_task_state_string(const char *s)
562{
563 long res = 0;
564 if (!s) {
565 s = kdbgetenv("PS");
566 if (!s)
567 s = "DRSTCZEU"; /* default value for ps */
568 }
569 while (*s) {
570 switch (*s) {
571 case 'D':
572 res |= TASK_UNINTERRUPTIBLE;
573 break;
574 case 'R':
575 res |= RUNNING;
576 break;
577 case 'S':
578 res |= TASK_INTERRUPTIBLE;
579 break;
580 case 'T':
581 res |= TASK_STOPPED;
582 break;
583 case 'C':
584 res |= TASK_TRACED;
585 break;
586 case 'Z':
587 res |= EXIT_ZOMBIE << 16;
588 break;
589 case 'E':
590 res |= EXIT_DEAD << 16;
591 break;
592 case 'U':
593 res |= UNRUNNABLE;
594 break;
595 case 'I':
596 res |= IDLE;
597 break;
598 case 'M':
599 res |= DAEMON;
600 break;
601 case 'A':
602 res = ~0UL;
603 break;
604 default:
605 kdb_printf("%s: unknown flag '%c' ignored\n",
606 __func__, *s);
607 break;
608 }
609 ++s;
610 }
611 return res;
612}
613
614/*
615 * kdb_task_state_char - Return the character that represents the task state.
616 * Inputs:
617 * p struct task for the process
618 * Returns:
619 * One character to represent the task state.
620 */
621char kdb_task_state_char (const struct task_struct *p)
622{
623 int cpu;
624 char state;
625 unsigned long tmp;
626
627 if (!p || probe_kernel_read(&tmp, (char *)p, sizeof(unsigned long)))
628 return 'E';
629
630 cpu = kdb_process_cpu(p);
631 state = (p->state == 0) ? 'R' :
632 (p->state < 0) ? 'U' :
633 (p->state & TASK_UNINTERRUPTIBLE) ? 'D' :
634 (p->state & TASK_STOPPED) ? 'T' :
635 (p->state & TASK_TRACED) ? 'C' :
636 (p->exit_state & EXIT_ZOMBIE) ? 'Z' :
637 (p->exit_state & EXIT_DEAD) ? 'E' :
638 (p->state & TASK_INTERRUPTIBLE) ? 'S' : '?';
639 if (is_idle_task(p)) {
640 /* Idle task. Is it really idle, apart from the kdb
641 * interrupt? */
642 if (!kdb_task_has_cpu(p) || kgdb_info[cpu].irq_depth == 1) {
643 if (cpu != kdb_initial_cpu)
644 state = 'I'; /* idle task */
645 }
646 } else if (!p->mm && state == 'S') {
647 state = 'M'; /* sleeping system daemon */
648 }
649 return state;
650}
651
652/*
653 * kdb_task_state - Return true if a process has the desired state
654 * given by the mask.
655 * Inputs:
656 * p struct task for the process
657 * mask mask from kdb_task_state_string to select processes
658 * Returns:
659 * True if the process matches at least one criteria defined by the mask.
660 */
661unsigned long kdb_task_state(const struct task_struct *p, unsigned long mask)
662{
663 char state[] = { kdb_task_state_char(p), '\0' };
664 return (mask & kdb_task_state_string(state)) != 0;
665}
666
667/*
668 * kdb_print_nameval - Print a name and its value, converting the
669 * value to a symbol lookup if possible.
670 * Inputs:
671 * name field name to print
672 * val value of field
673 */
674void kdb_print_nameval(const char *name, unsigned long val)
675{
676 kdb_symtab_t symtab;
677 kdb_printf(" %-11.11s ", name);
678 if (kdbnearsym(val, &symtab))
679 kdb_symbol_print(val, &symtab,
680 KDB_SP_VALUE|KDB_SP_SYMSIZE|KDB_SP_NEWLINE);
681 else
682 kdb_printf("0x%lx\n", val);
683}
684
685/* Last ditch allocator for debugging, so we can still debug even when
686 * the GFP_ATOMIC pool has been exhausted. The algorithms are tuned
687 * for space usage, not for speed. One smallish memory pool, the free
688 * chain is always in ascending address order to allow coalescing,
689 * allocations are done in brute force best fit.
690 */
691
692struct debug_alloc_header {
693 u32 next; /* offset of next header from start of pool */
694 u32 size;
695 void *caller;
696};
697
698/* The memory returned by this allocator must be aligned, which means
699 * so must the header size. Do not assume that sizeof(struct
700 * debug_alloc_header) is a multiple of the alignment, explicitly
701 * calculate the overhead of this header, including the alignment.
702 * The rest of this code must not use sizeof() on any header or
703 * pointer to a header.
704 */
705#define dah_align 8
706#define dah_overhead ALIGN(sizeof(struct debug_alloc_header), dah_align)
707
708static u64 debug_alloc_pool_aligned[256*1024/dah_align]; /* 256K pool */
709static char *debug_alloc_pool = (char *)debug_alloc_pool_aligned;
710static u32 dah_first, dah_first_call = 1, dah_used, dah_used_max;
711
712/* Locking is awkward. The debug code is called from all contexts,
713 * including non maskable interrupts. A normal spinlock is not safe
714 * in NMI context. Try to get the debug allocator lock, if it cannot
715 * be obtained after a second then give up. If the lock could not be
716 * previously obtained on this cpu then only try once.
717 *
718 * sparse has no annotation for "this function _sometimes_ acquires a
719 * lock", so fudge the acquire/release notation.
720 */
721static DEFINE_SPINLOCK(dap_lock);
722static int get_dap_lock(void)
723 __acquires(dap_lock)
724{
725 static int dap_locked = -1;
726 int count;
727 if (dap_locked == smp_processor_id())
728 count = 1;
729 else
730 count = 1000;
731 while (1) {
732 if (spin_trylock(&dap_lock)) {
733 dap_locked = -1;
734 return 1;
735 }
736 if (!count--)
737 break;
738 udelay(1000);
739 }
740 dap_locked = smp_processor_id();
741 __acquire(dap_lock);
742 return 0;
743}
744
745void *debug_kmalloc(size_t size, gfp_t flags)
746{
747 unsigned int rem, h_offset;
748 struct debug_alloc_header *best, *bestprev, *prev, *h;
749 void *p = NULL;
750 if (!get_dap_lock()) {
751 __release(dap_lock); /* we never actually got it */
752 return NULL;
753 }
754 h = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
755 if (dah_first_call) {
756 h->size = sizeof(debug_alloc_pool_aligned) - dah_overhead;
757 dah_first_call = 0;
758 }
759 size = ALIGN(size, dah_align);
760 prev = best = bestprev = NULL;
761 while (1) {
762 if (h->size >= size && (!best || h->size < best->size)) {
763 best = h;
764 bestprev = prev;
765 if (h->size == size)
766 break;
767 }
768 if (!h->next)
769 break;
770 prev = h;
771 h = (struct debug_alloc_header *)(debug_alloc_pool + h->next);
772 }
773 if (!best)
774 goto out;
775 rem = best->size - size;
776 /* The pool must always contain at least one header */
777 if (best->next == 0 && bestprev == NULL && rem < dah_overhead)
778 goto out;
779 if (rem >= dah_overhead) {
780 best->size = size;
781 h_offset = ((char *)best - debug_alloc_pool) +
782 dah_overhead + best->size;
783 h = (struct debug_alloc_header *)(debug_alloc_pool + h_offset);
784 h->size = rem - dah_overhead;
785 h->next = best->next;
786 } else
787 h_offset = best->next;
788 best->caller = __builtin_return_address(0);
789 dah_used += best->size;
790 dah_used_max = max(dah_used, dah_used_max);
791 if (bestprev)
792 bestprev->next = h_offset;
793 else
794 dah_first = h_offset;
795 p = (char *)best + dah_overhead;
796 memset(p, POISON_INUSE, best->size - 1);
797 *((char *)p + best->size - 1) = POISON_END;
798out:
799 spin_unlock(&dap_lock);
800 return p;
801}
802
803void debug_kfree(void *p)
804{
805 struct debug_alloc_header *h;
806 unsigned int h_offset;
807 if (!p)
808 return;
809 if ((char *)p < debug_alloc_pool ||
810 (char *)p >= debug_alloc_pool + sizeof(debug_alloc_pool_aligned)) {
811 kfree(p);
812 return;
813 }
814 if (!get_dap_lock()) {
815 __release(dap_lock); /* we never actually got it */
816 return; /* memory leak, cannot be helped */
817 }
818 h = (struct debug_alloc_header *)((char *)p - dah_overhead);
819 memset(p, POISON_FREE, h->size - 1);
820 *((char *)p + h->size - 1) = POISON_END;
821 h->caller = NULL;
822 dah_used -= h->size;
823 h_offset = (char *)h - debug_alloc_pool;
824 if (h_offset < dah_first) {
825 h->next = dah_first;
826 dah_first = h_offset;
827 } else {
828 struct debug_alloc_header *prev;
829 unsigned int prev_offset;
830 prev = (struct debug_alloc_header *)(debug_alloc_pool +
831 dah_first);
832 while (1) {
833 if (!prev->next || prev->next > h_offset)
834 break;
835 prev = (struct debug_alloc_header *)
836 (debug_alloc_pool + prev->next);
837 }
838 prev_offset = (char *)prev - debug_alloc_pool;
839 if (prev_offset + dah_overhead + prev->size == h_offset) {
840 prev->size += dah_overhead + h->size;
841 memset(h, POISON_FREE, dah_overhead - 1);
842 *((char *)h + dah_overhead - 1) = POISON_END;
843 h = prev;
844 h_offset = prev_offset;
845 } else {
846 h->next = prev->next;
847 prev->next = h_offset;
848 }
849 }
850 if (h_offset + dah_overhead + h->size == h->next) {
851 struct debug_alloc_header *next;
852 next = (struct debug_alloc_header *)
853 (debug_alloc_pool + h->next);
854 h->size += dah_overhead + next->size;
855 h->next = next->next;
856 memset(next, POISON_FREE, dah_overhead - 1);
857 *((char *)next + dah_overhead - 1) = POISON_END;
858 }
859 spin_unlock(&dap_lock);
860}
861
862void debug_kusage(void)
863{
864 struct debug_alloc_header *h_free, *h_used;
865#ifdef CONFIG_IA64
866 /* FIXME: using dah for ia64 unwind always results in a memory leak.
867 * Fix that memory leak first, then set debug_kusage_one_time = 1 for
868 * all architectures.
869 */
870 static int debug_kusage_one_time;
871#else
872 static int debug_kusage_one_time = 1;
873#endif
874 if (!get_dap_lock()) {
875 __release(dap_lock); /* we never actually got it */
876 return;
877 }
878 h_free = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
879 if (dah_first == 0 &&
880 (h_free->size == sizeof(debug_alloc_pool_aligned) - dah_overhead ||
881 dah_first_call))
882 goto out;
883 if (!debug_kusage_one_time)
884 goto out;
885 debug_kusage_one_time = 0;
886 kdb_printf("%s: debug_kmalloc memory leak dah_first %d\n",
887 __func__, dah_first);
888 if (dah_first) {
889 h_used = (struct debug_alloc_header *)debug_alloc_pool;
890 kdb_printf("%s: h_used %p size %d\n", __func__, h_used,
891 h_used->size);
892 }
893 do {
894 h_used = (struct debug_alloc_header *)
895 ((char *)h_free + dah_overhead + h_free->size);
896 kdb_printf("%s: h_used %p size %d caller %p\n",
897 __func__, h_used, h_used->size, h_used->caller);
898 h_free = (struct debug_alloc_header *)
899 (debug_alloc_pool + h_free->next);
900 } while (h_free->next);
901 h_used = (struct debug_alloc_header *)
902 ((char *)h_free + dah_overhead + h_free->size);
903 if ((char *)h_used - debug_alloc_pool !=
904 sizeof(debug_alloc_pool_aligned))
905 kdb_printf("%s: h_used %p size %d caller %p\n",
906 __func__, h_used, h_used->size, h_used->caller);
907out:
908 spin_unlock(&dap_lock);
909}
910
911/* Maintain a small stack of kdb_flags to allow recursion without disturbing
912 * the global kdb state.
913 */
914
915static int kdb_flags_stack[4], kdb_flags_index;
916
917void kdb_save_flags(void)
918{
919 BUG_ON(kdb_flags_index >= ARRAY_SIZE(kdb_flags_stack));
920 kdb_flags_stack[kdb_flags_index++] = kdb_flags;
921}
922
923void kdb_restore_flags(void)
924{
925 BUG_ON(kdb_flags_index <= 0);
926 kdb_flags = kdb_flags_stack[--kdb_flags_index];
927}
1/*
2 * Kernel Debugger Architecture Independent Support Functions
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) 2009 Wind River Systems, Inc. All Rights Reserved.
10 * 03/02/13 added new 2.5 kallsyms <xavier.bru@bull.net>
11 */
12
13#include <stdarg.h>
14#include <linux/types.h>
15#include <linux/sched.h>
16#include <linux/mm.h>
17#include <linux/kallsyms.h>
18#include <linux/stddef.h>
19#include <linux/vmalloc.h>
20#include <linux/ptrace.h>
21#include <linux/module.h>
22#include <linux/highmem.h>
23#include <linux/hardirq.h>
24#include <linux/delay.h>
25#include <linux/uaccess.h>
26#include <linux/kdb.h>
27#include <linux/slab.h>
28#include "kdb_private.h"
29
30/*
31 * kdbgetsymval - Return the address of the given symbol.
32 *
33 * Parameters:
34 * symname Character string containing symbol name
35 * symtab Structure to receive results
36 * Returns:
37 * 0 Symbol not found, symtab zero filled
38 * 1 Symbol mapped to module/symbol/section, data in symtab
39 */
40int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
41{
42 kdb_dbg_printf(AR, "symname=%s, symtab=%px\n", symname, symtab);
43 memset(symtab, 0, sizeof(*symtab));
44 symtab->sym_start = kallsyms_lookup_name(symname);
45 if (symtab->sym_start) {
46 kdb_dbg_printf(AR, "returns 1, symtab->sym_start=0x%lx\n",
47 symtab->sym_start);
48 return 1;
49 }
50 kdb_dbg_printf(AR, "returns 0\n");
51 return 0;
52}
53EXPORT_SYMBOL(kdbgetsymval);
54
55static char *kdb_name_table[100]; /* arbitrary size */
56
57/*
58 * kdbnearsym - Return the name of the symbol with the nearest address
59 * less than 'addr'.
60 *
61 * Parameters:
62 * addr Address to check for symbol near
63 * symtab Structure to receive results
64 * Returns:
65 * 0 No sections contain this address, symtab zero filled
66 * 1 Address mapped to module/symbol/section, data in symtab
67 * Remarks:
68 * 2.6 kallsyms has a "feature" where it unpacks the name into a
69 * string. If that string is reused before the caller expects it
70 * then the caller sees its string change without warning. To
71 * avoid cluttering up the main kdb code with lots of kdb_strdup,
72 * tests and kfree calls, kdbnearsym maintains an LRU list of the
73 * last few unique strings. The list is sized large enough to
74 * hold active strings, no kdb caller of kdbnearsym makes more
75 * than ~20 later calls before using a saved value.
76 */
77int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
78{
79 int ret = 0;
80 unsigned long symbolsize = 0;
81 unsigned long offset = 0;
82#define knt1_size 128 /* must be >= kallsyms table size */
83 char *knt1 = NULL;
84
85 kdb_dbg_printf(AR, "addr=0x%lx, symtab=%px\n", addr, symtab);
86 memset(symtab, 0, sizeof(*symtab));
87
88 if (addr < 4096)
89 goto out;
90 knt1 = debug_kmalloc(knt1_size, GFP_ATOMIC);
91 if (!knt1) {
92 kdb_func_printf("addr=0x%lx cannot kmalloc knt1\n", addr);
93 goto out;
94 }
95 symtab->sym_name = kallsyms_lookup(addr, &symbolsize , &offset,
96 (char **)(&symtab->mod_name), knt1);
97 if (offset > 8*1024*1024) {
98 symtab->sym_name = NULL;
99 addr = offset = symbolsize = 0;
100 }
101 symtab->sym_start = addr - offset;
102 symtab->sym_end = symtab->sym_start + symbolsize;
103 ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0';
104
105 if (ret) {
106 int i;
107 /* Another 2.6 kallsyms "feature". Sometimes the sym_name is
108 * set but the buffer passed into kallsyms_lookup is not used,
109 * so it contains garbage. The caller has to work out which
110 * buffer needs to be saved.
111 *
112 * What was Rusty smoking when he wrote that code?
113 */
114 if (symtab->sym_name != knt1) {
115 strncpy(knt1, symtab->sym_name, knt1_size);
116 knt1[knt1_size-1] = '\0';
117 }
118 for (i = 0; i < ARRAY_SIZE(kdb_name_table); ++i) {
119 if (kdb_name_table[i] &&
120 strcmp(kdb_name_table[i], knt1) == 0)
121 break;
122 }
123 if (i >= ARRAY_SIZE(kdb_name_table)) {
124 debug_kfree(kdb_name_table[0]);
125 memmove(kdb_name_table, kdb_name_table+1,
126 sizeof(kdb_name_table[0]) *
127 (ARRAY_SIZE(kdb_name_table)-1));
128 } else {
129 debug_kfree(knt1);
130 knt1 = kdb_name_table[i];
131 memmove(kdb_name_table+i, kdb_name_table+i+1,
132 sizeof(kdb_name_table[0]) *
133 (ARRAY_SIZE(kdb_name_table)-i-1));
134 }
135 i = ARRAY_SIZE(kdb_name_table) - 1;
136 kdb_name_table[i] = knt1;
137 symtab->sym_name = kdb_name_table[i];
138 knt1 = NULL;
139 }
140
141 if (symtab->mod_name == NULL)
142 symtab->mod_name = "kernel";
143 kdb_dbg_printf(AR, "returns %d symtab->sym_start=0x%lx, symtab->mod_name=%px, symtab->sym_name=%px (%s)\n",
144 ret, symtab->sym_start, symtab->mod_name, symtab->sym_name, symtab->sym_name);
145
146out:
147 debug_kfree(knt1);
148 return ret;
149}
150
151void kdbnearsym_cleanup(void)
152{
153 int i;
154 for (i = 0; i < ARRAY_SIZE(kdb_name_table); ++i) {
155 if (kdb_name_table[i]) {
156 debug_kfree(kdb_name_table[i]);
157 kdb_name_table[i] = NULL;
158 }
159 }
160}
161
162static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1];
163
164/*
165 * kallsyms_symbol_complete
166 *
167 * Parameters:
168 * prefix_name prefix of a symbol name to lookup
169 * max_len maximum length that can be returned
170 * Returns:
171 * Number of symbols which match the given prefix.
172 * Notes:
173 * prefix_name is changed to contain the longest unique prefix that
174 * starts with this prefix (tab completion).
175 */
176int kallsyms_symbol_complete(char *prefix_name, int max_len)
177{
178 loff_t pos = 0;
179 int prefix_len = strlen(prefix_name), prev_len = 0;
180 int i, number = 0;
181 const char *name;
182
183 while ((name = kdb_walk_kallsyms(&pos))) {
184 if (strncmp(name, prefix_name, prefix_len) == 0) {
185 strscpy(ks_namebuf, name, sizeof(ks_namebuf));
186 /* Work out the longest name that matches the prefix */
187 if (++number == 1) {
188 prev_len = min_t(int, max_len-1,
189 strlen(ks_namebuf));
190 memcpy(ks_namebuf_prev, ks_namebuf, prev_len);
191 ks_namebuf_prev[prev_len] = '\0';
192 continue;
193 }
194 for (i = 0; i < prev_len; i++) {
195 if (ks_namebuf[i] != ks_namebuf_prev[i]) {
196 prev_len = i;
197 ks_namebuf_prev[i] = '\0';
198 break;
199 }
200 }
201 }
202 }
203 if (prev_len > prefix_len)
204 memcpy(prefix_name, ks_namebuf_prev, prev_len+1);
205 return number;
206}
207
208/*
209 * kallsyms_symbol_next
210 *
211 * Parameters:
212 * prefix_name prefix of a symbol name to lookup
213 * flag 0 means search from the head, 1 means continue search.
214 * buf_size maximum length that can be written to prefix_name
215 * buffer
216 * Returns:
217 * 1 if a symbol matches the given prefix.
218 * 0 if no string found
219 */
220int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size)
221{
222 int prefix_len = strlen(prefix_name);
223 static loff_t pos;
224 const char *name;
225
226 if (!flag)
227 pos = 0;
228
229 while ((name = kdb_walk_kallsyms(&pos))) {
230 if (!strncmp(name, prefix_name, prefix_len))
231 return strscpy(prefix_name, name, buf_size);
232 }
233 return 0;
234}
235
236/*
237 * kdb_symbol_print - Standard method for printing a symbol name and offset.
238 * Inputs:
239 * addr Address to be printed.
240 * symtab Address of symbol data, if NULL this routine does its
241 * own lookup.
242 * punc Punctuation for string, bit field.
243 * Remarks:
244 * The string and its punctuation is only printed if the address
245 * is inside the kernel, except that the value is always printed
246 * when requested.
247 */
248void kdb_symbol_print(unsigned long addr, const kdb_symtab_t *symtab_p,
249 unsigned int punc)
250{
251 kdb_symtab_t symtab, *symtab_p2;
252 if (symtab_p) {
253 symtab_p2 = (kdb_symtab_t *)symtab_p;
254 } else {
255 symtab_p2 = &symtab;
256 kdbnearsym(addr, symtab_p2);
257 }
258 if (!(symtab_p2->sym_name || (punc & KDB_SP_VALUE)))
259 return;
260 if (punc & KDB_SP_SPACEB)
261 kdb_printf(" ");
262 if (punc & KDB_SP_VALUE)
263 kdb_printf(kdb_machreg_fmt0, addr);
264 if (symtab_p2->sym_name) {
265 if (punc & KDB_SP_VALUE)
266 kdb_printf(" ");
267 if (punc & KDB_SP_PAREN)
268 kdb_printf("(");
269 if (strcmp(symtab_p2->mod_name, "kernel"))
270 kdb_printf("[%s]", symtab_p2->mod_name);
271 kdb_printf("%s", symtab_p2->sym_name);
272 if (addr != symtab_p2->sym_start)
273 kdb_printf("+0x%lx", addr - symtab_p2->sym_start);
274 if (punc & KDB_SP_SYMSIZE)
275 kdb_printf("/0x%lx",
276 symtab_p2->sym_end - symtab_p2->sym_start);
277 if (punc & KDB_SP_PAREN)
278 kdb_printf(")");
279 }
280 if (punc & KDB_SP_SPACEA)
281 kdb_printf(" ");
282 if (punc & KDB_SP_NEWLINE)
283 kdb_printf("\n");
284}
285
286/*
287 * kdb_strdup - kdb equivalent of strdup, for disasm code.
288 * Inputs:
289 * str The string to duplicate.
290 * type Flags to kmalloc for the new string.
291 * Returns:
292 * Address of the new string, NULL if storage could not be allocated.
293 * Remarks:
294 * This is not in lib/string.c because it uses kmalloc which is not
295 * available when string.o is used in boot loaders.
296 */
297char *kdb_strdup(const char *str, gfp_t type)
298{
299 int n = strlen(str)+1;
300 char *s = kmalloc(n, type);
301 if (!s)
302 return NULL;
303 return strcpy(s, str);
304}
305
306/*
307 * kdb_getarea_size - Read an area of data. The kdb equivalent of
308 * copy_from_user, with kdb messages for invalid addresses.
309 * Inputs:
310 * res Pointer to the area to receive the result.
311 * addr Address of the area to copy.
312 * size Size of the area.
313 * Returns:
314 * 0 for success, < 0 for error.
315 */
316int kdb_getarea_size(void *res, unsigned long addr, size_t size)
317{
318 int ret = copy_from_kernel_nofault((char *)res, (char *)addr, size);
319 if (ret) {
320 if (!KDB_STATE(SUPPRESS)) {
321 kdb_func_printf("Bad address 0x%lx\n", addr);
322 KDB_STATE_SET(SUPPRESS);
323 }
324 ret = KDB_BADADDR;
325 } else {
326 KDB_STATE_CLEAR(SUPPRESS);
327 }
328 return ret;
329}
330
331/*
332 * kdb_putarea_size - Write an area of data. The kdb equivalent of
333 * copy_to_user, with kdb messages for invalid addresses.
334 * Inputs:
335 * addr Address of the area to write to.
336 * res Pointer to the area holding the data.
337 * size Size of the area.
338 * Returns:
339 * 0 for success, < 0 for error.
340 */
341int kdb_putarea_size(unsigned long addr, void *res, size_t size)
342{
343 int ret = copy_from_kernel_nofault((char *)addr, (char *)res, size);
344 if (ret) {
345 if (!KDB_STATE(SUPPRESS)) {
346 kdb_func_printf("Bad address 0x%lx\n", addr);
347 KDB_STATE_SET(SUPPRESS);
348 }
349 ret = KDB_BADADDR;
350 } else {
351 KDB_STATE_CLEAR(SUPPRESS);
352 }
353 return ret;
354}
355
356/*
357 * kdb_getphys - Read data from a physical address. Validate the
358 * address is in range, use kmap_atomic() to get data
359 * similar to kdb_getarea() - but for phys addresses
360 * Inputs:
361 * res Pointer to the word to receive the result
362 * addr Physical address of the area to copy
363 * size Size of the area
364 * Returns:
365 * 0 for success, < 0 for error.
366 */
367static int kdb_getphys(void *res, unsigned long addr, size_t size)
368{
369 unsigned long pfn;
370 void *vaddr;
371 struct page *page;
372
373 pfn = (addr >> PAGE_SHIFT);
374 if (!pfn_valid(pfn))
375 return 1;
376 page = pfn_to_page(pfn);
377 vaddr = kmap_atomic(page);
378 memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size);
379 kunmap_atomic(vaddr);
380
381 return 0;
382}
383
384/*
385 * kdb_getphysword
386 * Inputs:
387 * word Pointer to the word to receive the result.
388 * addr Address of the area to copy.
389 * size Size of the area.
390 * Returns:
391 * 0 for success, < 0 for error.
392 */
393int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
394{
395 int diag;
396 __u8 w1;
397 __u16 w2;
398 __u32 w4;
399 __u64 w8;
400 *word = 0; /* Default value if addr or size is invalid */
401
402 switch (size) {
403 case 1:
404 diag = kdb_getphys(&w1, addr, sizeof(w1));
405 if (!diag)
406 *word = w1;
407 break;
408 case 2:
409 diag = kdb_getphys(&w2, addr, sizeof(w2));
410 if (!diag)
411 *word = w2;
412 break;
413 case 4:
414 diag = kdb_getphys(&w4, addr, sizeof(w4));
415 if (!diag)
416 *word = w4;
417 break;
418 case 8:
419 if (size <= sizeof(*word)) {
420 diag = kdb_getphys(&w8, addr, sizeof(w8));
421 if (!diag)
422 *word = w8;
423 break;
424 }
425 fallthrough;
426 default:
427 diag = KDB_BADWIDTH;
428 kdb_func_printf("bad width %zu\n", size);
429 }
430 return diag;
431}
432
433/*
434 * kdb_getword - Read a binary value. Unlike kdb_getarea, this treats
435 * data as numbers.
436 * Inputs:
437 * word Pointer to the word to receive the result.
438 * addr Address of the area to copy.
439 * size Size of the area.
440 * Returns:
441 * 0 for success, < 0 for error.
442 */
443int kdb_getword(unsigned long *word, unsigned long addr, size_t size)
444{
445 int diag;
446 __u8 w1;
447 __u16 w2;
448 __u32 w4;
449 __u64 w8;
450 *word = 0; /* Default value if addr or size is invalid */
451 switch (size) {
452 case 1:
453 diag = kdb_getarea(w1, addr);
454 if (!diag)
455 *word = w1;
456 break;
457 case 2:
458 diag = kdb_getarea(w2, addr);
459 if (!diag)
460 *word = w2;
461 break;
462 case 4:
463 diag = kdb_getarea(w4, addr);
464 if (!diag)
465 *word = w4;
466 break;
467 case 8:
468 if (size <= sizeof(*word)) {
469 diag = kdb_getarea(w8, addr);
470 if (!diag)
471 *word = w8;
472 break;
473 }
474 fallthrough;
475 default:
476 diag = KDB_BADWIDTH;
477 kdb_func_printf("bad width %zu\n", size);
478 }
479 return diag;
480}
481
482/*
483 * kdb_putword - Write a binary value. Unlike kdb_putarea, this
484 * treats data as numbers.
485 * Inputs:
486 * addr Address of the area to write to..
487 * word The value to set.
488 * size Size of the area.
489 * Returns:
490 * 0 for success, < 0 for error.
491 */
492int kdb_putword(unsigned long addr, unsigned long word, size_t size)
493{
494 int diag;
495 __u8 w1;
496 __u16 w2;
497 __u32 w4;
498 __u64 w8;
499 switch (size) {
500 case 1:
501 w1 = word;
502 diag = kdb_putarea(addr, w1);
503 break;
504 case 2:
505 w2 = word;
506 diag = kdb_putarea(addr, w2);
507 break;
508 case 4:
509 w4 = word;
510 diag = kdb_putarea(addr, w4);
511 break;
512 case 8:
513 if (size <= sizeof(word)) {
514 w8 = word;
515 diag = kdb_putarea(addr, w8);
516 break;
517 }
518 fallthrough;
519 default:
520 diag = KDB_BADWIDTH;
521 kdb_func_printf("bad width %zu\n", size);
522 }
523 return diag;
524}
525
526/*
527 * kdb_task_state_string - Convert a string containing any of the
528 * letters DRSTCZEUIMA to a mask for the process state field and
529 * return the value. If no argument is supplied, return the mask
530 * that corresponds to environment variable PS, DRSTCZEU by
531 * default.
532 * Inputs:
533 * s String to convert
534 * Returns:
535 * Mask for process state.
536 * Notes:
537 * The mask folds data from several sources into a single long value, so
538 * be careful not to overlap the bits. TASK_* bits are in the LSB,
539 * special cases like UNRUNNABLE are in the MSB. As of 2.6.10-rc1 there
540 * is no overlap between TASK_* and EXIT_* but that may not always be
541 * true, so EXIT_* bits are shifted left 16 bits before being stored in
542 * the mask.
543 */
544
545/* unrunnable is < 0 */
546#define UNRUNNABLE (1UL << (8*sizeof(unsigned long) - 1))
547#define RUNNING (1UL << (8*sizeof(unsigned long) - 2))
548#define IDLE (1UL << (8*sizeof(unsigned long) - 3))
549#define DAEMON (1UL << (8*sizeof(unsigned long) - 4))
550
551unsigned long kdb_task_state_string(const char *s)
552{
553 long res = 0;
554 if (!s) {
555 s = kdbgetenv("PS");
556 if (!s)
557 s = "DRSTCZEU"; /* default value for ps */
558 }
559 while (*s) {
560 switch (*s) {
561 case 'D':
562 res |= TASK_UNINTERRUPTIBLE;
563 break;
564 case 'R':
565 res |= RUNNING;
566 break;
567 case 'S':
568 res |= TASK_INTERRUPTIBLE;
569 break;
570 case 'T':
571 res |= TASK_STOPPED;
572 break;
573 case 'C':
574 res |= TASK_TRACED;
575 break;
576 case 'Z':
577 res |= EXIT_ZOMBIE << 16;
578 break;
579 case 'E':
580 res |= EXIT_DEAD << 16;
581 break;
582 case 'U':
583 res |= UNRUNNABLE;
584 break;
585 case 'I':
586 res |= IDLE;
587 break;
588 case 'M':
589 res |= DAEMON;
590 break;
591 case 'A':
592 res = ~0UL;
593 break;
594 default:
595 kdb_func_printf("unknown flag '%c' ignored\n", *s);
596 break;
597 }
598 ++s;
599 }
600 return res;
601}
602
603/*
604 * kdb_task_state_char - Return the character that represents the task state.
605 * Inputs:
606 * p struct task for the process
607 * Returns:
608 * One character to represent the task state.
609 */
610char kdb_task_state_char (const struct task_struct *p)
611{
612 unsigned int p_state;
613 unsigned long tmp;
614 char state;
615 int cpu;
616
617 if (!p ||
618 copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
619 return 'E';
620
621 cpu = kdb_process_cpu(p);
622 p_state = READ_ONCE(p->__state);
623 state = (p_state == 0) ? 'R' :
624 (p_state < 0) ? 'U' :
625 (p_state & TASK_UNINTERRUPTIBLE) ? 'D' :
626 (p_state & TASK_STOPPED) ? 'T' :
627 (p_state & TASK_TRACED) ? 'C' :
628 (p->exit_state & EXIT_ZOMBIE) ? 'Z' :
629 (p->exit_state & EXIT_DEAD) ? 'E' :
630 (p_state & TASK_INTERRUPTIBLE) ? 'S' : '?';
631 if (is_idle_task(p)) {
632 /* Idle task. Is it really idle, apart from the kdb
633 * interrupt? */
634 if (!kdb_task_has_cpu(p) || kgdb_info[cpu].irq_depth == 1) {
635 if (cpu != kdb_initial_cpu)
636 state = 'I'; /* idle task */
637 }
638 } else if (!p->mm && state == 'S') {
639 state = 'M'; /* sleeping system daemon */
640 }
641 return state;
642}
643
644/*
645 * kdb_task_state - Return true if a process has the desired state
646 * given by the mask.
647 * Inputs:
648 * p struct task for the process
649 * mask mask from kdb_task_state_string to select processes
650 * Returns:
651 * True if the process matches at least one criteria defined by the mask.
652 */
653unsigned long kdb_task_state(const struct task_struct *p, unsigned long mask)
654{
655 char state[] = { kdb_task_state_char(p), '\0' };
656 return (mask & kdb_task_state_string(state)) != 0;
657}
658
659/* Last ditch allocator for debugging, so we can still debug even when
660 * the GFP_ATOMIC pool has been exhausted. The algorithms are tuned
661 * for space usage, not for speed. One smallish memory pool, the free
662 * chain is always in ascending address order to allow coalescing,
663 * allocations are done in brute force best fit.
664 */
665
666struct debug_alloc_header {
667 u32 next; /* offset of next header from start of pool */
668 u32 size;
669 void *caller;
670};
671
672/* The memory returned by this allocator must be aligned, which means
673 * so must the header size. Do not assume that sizeof(struct
674 * debug_alloc_header) is a multiple of the alignment, explicitly
675 * calculate the overhead of this header, including the alignment.
676 * The rest of this code must not use sizeof() on any header or
677 * pointer to a header.
678 */
679#define dah_align 8
680#define dah_overhead ALIGN(sizeof(struct debug_alloc_header), dah_align)
681
682static u64 debug_alloc_pool_aligned[256*1024/dah_align]; /* 256K pool */
683static char *debug_alloc_pool = (char *)debug_alloc_pool_aligned;
684static u32 dah_first, dah_first_call = 1, dah_used, dah_used_max;
685
686/* Locking is awkward. The debug code is called from all contexts,
687 * including non maskable interrupts. A normal spinlock is not safe
688 * in NMI context. Try to get the debug allocator lock, if it cannot
689 * be obtained after a second then give up. If the lock could not be
690 * previously obtained on this cpu then only try once.
691 *
692 * sparse has no annotation for "this function _sometimes_ acquires a
693 * lock", so fudge the acquire/release notation.
694 */
695static DEFINE_SPINLOCK(dap_lock);
696static int get_dap_lock(void)
697 __acquires(dap_lock)
698{
699 static int dap_locked = -1;
700 int count;
701 if (dap_locked == smp_processor_id())
702 count = 1;
703 else
704 count = 1000;
705 while (1) {
706 if (spin_trylock(&dap_lock)) {
707 dap_locked = -1;
708 return 1;
709 }
710 if (!count--)
711 break;
712 udelay(1000);
713 }
714 dap_locked = smp_processor_id();
715 __acquire(dap_lock);
716 return 0;
717}
718
719void *debug_kmalloc(size_t size, gfp_t flags)
720{
721 unsigned int rem, h_offset;
722 struct debug_alloc_header *best, *bestprev, *prev, *h;
723 void *p = NULL;
724 if (!get_dap_lock()) {
725 __release(dap_lock); /* we never actually got it */
726 return NULL;
727 }
728 h = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
729 if (dah_first_call) {
730 h->size = sizeof(debug_alloc_pool_aligned) - dah_overhead;
731 dah_first_call = 0;
732 }
733 size = ALIGN(size, dah_align);
734 prev = best = bestprev = NULL;
735 while (1) {
736 if (h->size >= size && (!best || h->size < best->size)) {
737 best = h;
738 bestprev = prev;
739 if (h->size == size)
740 break;
741 }
742 if (!h->next)
743 break;
744 prev = h;
745 h = (struct debug_alloc_header *)(debug_alloc_pool + h->next);
746 }
747 if (!best)
748 goto out;
749 rem = best->size - size;
750 /* The pool must always contain at least one header */
751 if (best->next == 0 && bestprev == NULL && rem < dah_overhead)
752 goto out;
753 if (rem >= dah_overhead) {
754 best->size = size;
755 h_offset = ((char *)best - debug_alloc_pool) +
756 dah_overhead + best->size;
757 h = (struct debug_alloc_header *)(debug_alloc_pool + h_offset);
758 h->size = rem - dah_overhead;
759 h->next = best->next;
760 } else
761 h_offset = best->next;
762 best->caller = __builtin_return_address(0);
763 dah_used += best->size;
764 dah_used_max = max(dah_used, dah_used_max);
765 if (bestprev)
766 bestprev->next = h_offset;
767 else
768 dah_first = h_offset;
769 p = (char *)best + dah_overhead;
770 memset(p, POISON_INUSE, best->size - 1);
771 *((char *)p + best->size - 1) = POISON_END;
772out:
773 spin_unlock(&dap_lock);
774 return p;
775}
776
777void debug_kfree(void *p)
778{
779 struct debug_alloc_header *h;
780 unsigned int h_offset;
781 if (!p)
782 return;
783 if ((char *)p < debug_alloc_pool ||
784 (char *)p >= debug_alloc_pool + sizeof(debug_alloc_pool_aligned)) {
785 kfree(p);
786 return;
787 }
788 if (!get_dap_lock()) {
789 __release(dap_lock); /* we never actually got it */
790 return; /* memory leak, cannot be helped */
791 }
792 h = (struct debug_alloc_header *)((char *)p - dah_overhead);
793 memset(p, POISON_FREE, h->size - 1);
794 *((char *)p + h->size - 1) = POISON_END;
795 h->caller = NULL;
796 dah_used -= h->size;
797 h_offset = (char *)h - debug_alloc_pool;
798 if (h_offset < dah_first) {
799 h->next = dah_first;
800 dah_first = h_offset;
801 } else {
802 struct debug_alloc_header *prev;
803 unsigned int prev_offset;
804 prev = (struct debug_alloc_header *)(debug_alloc_pool +
805 dah_first);
806 while (1) {
807 if (!prev->next || prev->next > h_offset)
808 break;
809 prev = (struct debug_alloc_header *)
810 (debug_alloc_pool + prev->next);
811 }
812 prev_offset = (char *)prev - debug_alloc_pool;
813 if (prev_offset + dah_overhead + prev->size == h_offset) {
814 prev->size += dah_overhead + h->size;
815 memset(h, POISON_FREE, dah_overhead - 1);
816 *((char *)h + dah_overhead - 1) = POISON_END;
817 h = prev;
818 h_offset = prev_offset;
819 } else {
820 h->next = prev->next;
821 prev->next = h_offset;
822 }
823 }
824 if (h_offset + dah_overhead + h->size == h->next) {
825 struct debug_alloc_header *next;
826 next = (struct debug_alloc_header *)
827 (debug_alloc_pool + h->next);
828 h->size += dah_overhead + next->size;
829 h->next = next->next;
830 memset(next, POISON_FREE, dah_overhead - 1);
831 *((char *)next + dah_overhead - 1) = POISON_END;
832 }
833 spin_unlock(&dap_lock);
834}
835
836void debug_kusage(void)
837{
838 struct debug_alloc_header *h_free, *h_used;
839#ifdef CONFIG_IA64
840 /* FIXME: using dah for ia64 unwind always results in a memory leak.
841 * Fix that memory leak first, then set debug_kusage_one_time = 1 for
842 * all architectures.
843 */
844 static int debug_kusage_one_time;
845#else
846 static int debug_kusage_one_time = 1;
847#endif
848 if (!get_dap_lock()) {
849 __release(dap_lock); /* we never actually got it */
850 return;
851 }
852 h_free = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
853 if (dah_first == 0 &&
854 (h_free->size == sizeof(debug_alloc_pool_aligned) - dah_overhead ||
855 dah_first_call))
856 goto out;
857 if (!debug_kusage_one_time)
858 goto out;
859 debug_kusage_one_time = 0;
860 kdb_func_printf("debug_kmalloc memory leak dah_first %d\n", dah_first);
861 if (dah_first) {
862 h_used = (struct debug_alloc_header *)debug_alloc_pool;
863 kdb_func_printf("h_used %px size %d\n", h_used, h_used->size);
864 }
865 do {
866 h_used = (struct debug_alloc_header *)
867 ((char *)h_free + dah_overhead + h_free->size);
868 kdb_func_printf("h_used %px size %d caller %px\n",
869 h_used, h_used->size, h_used->caller);
870 h_free = (struct debug_alloc_header *)
871 (debug_alloc_pool + h_free->next);
872 } while (h_free->next);
873 h_used = (struct debug_alloc_header *)
874 ((char *)h_free + dah_overhead + h_free->size);
875 if ((char *)h_used - debug_alloc_pool !=
876 sizeof(debug_alloc_pool_aligned))
877 kdb_func_printf("h_used %px size %d caller %px\n",
878 h_used, h_used->size, h_used->caller);
879out:
880 spin_unlock(&dap_lock);
881}
882
883/* Maintain a small stack of kdb_flags to allow recursion without disturbing
884 * the global kdb state.
885 */
886
887static int kdb_flags_stack[4], kdb_flags_index;
888
889void kdb_save_flags(void)
890{
891 BUG_ON(kdb_flags_index >= ARRAY_SIZE(kdb_flags_stack));
892 kdb_flags_stack[kdb_flags_index++] = kdb_flags;
893}
894
895void kdb_restore_flags(void)
896{
897 BUG_ON(kdb_flags_index <= 0);
898 kdb_flags = kdb_flags_stack[--kdb_flags_index];
899}