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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 <linux/types.h>
14#include <linux/sched.h>
15#include <linux/mm.h>
16#include <linux/kallsyms.h>
17#include <linux/stddef.h>
18#include <linux/vmalloc.h>
19#include <linux/ptrace.h>
20#include <linux/highmem.h>
21#include <linux/hardirq.h>
22#include <linux/delay.h>
23#include <linux/uaccess.h>
24#include <linux/kdb.h>
25#include <linux/slab.h>
26#include <linux/ctype.h>
27#include "kdb_private.h"
28
29/*
30 * kdbgetsymval - Return the address of the given symbol.
31 *
32 * Parameters:
33 * symname Character string containing symbol name
34 * symtab Structure to receive results
35 * Returns:
36 * 0 Symbol not found, symtab zero filled
37 * 1 Symbol mapped to module/symbol/section, data in symtab
38 */
39int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
40{
41 kdb_dbg_printf(AR, "symname=%s, symtab=%px\n", symname, symtab);
42 memset(symtab, 0, sizeof(*symtab));
43 symtab->sym_start = kallsyms_lookup_name(symname);
44 if (symtab->sym_start) {
45 kdb_dbg_printf(AR, "returns 1, symtab->sym_start=0x%lx\n",
46 symtab->sym_start);
47 return 1;
48 }
49 kdb_dbg_printf(AR, "returns 0\n");
50 return 0;
51}
52EXPORT_SYMBOL(kdbgetsymval);
53
54/**
55 * kdbnearsym() - Return the name of the symbol with the nearest address
56 * less than @addr.
57 * @addr: Address to check for near symbol
58 * @symtab: Structure to receive results
59 *
60 * WARNING: This function may return a pointer to a single statically
61 * allocated buffer (namebuf). kdb's unusual calling context (single
62 * threaded, all other CPUs halted) provides us sufficient locking for
63 * this to be safe. The only constraint imposed by the static buffer is
64 * that the caller must consume any previous reply prior to another call
65 * to lookup a new symbol.
66 *
67 * Note that, strictly speaking, some architectures may re-enter the kdb
68 * trap if the system turns out to be very badly damaged and this breaks
69 * the single-threaded assumption above. In these circumstances successful
70 * continuation and exit from the inner trap is unlikely to work and any
71 * user attempting this receives a prominent warning before being allowed
72 * to progress. In these circumstances we remain memory safe because
73 * namebuf[KSYM_NAME_LEN-1] will never change from '\0' although we do
74 * tolerate the possibility of garbled symbol display from the outer kdb
75 * trap.
76 *
77 * Return:
78 * * 0 - No sections contain this address, symtab zero filled
79 * * 1 - Address mapped to module/symbol/section, data in symtab
80 */
81int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
82{
83 int ret = 0;
84 unsigned long symbolsize = 0;
85 unsigned long offset = 0;
86 static char namebuf[KSYM_NAME_LEN];
87
88 kdb_dbg_printf(AR, "addr=0x%lx, symtab=%px\n", addr, symtab);
89 memset(symtab, 0, sizeof(*symtab));
90
91 if (addr < 4096)
92 goto out;
93
94 symtab->sym_name = kallsyms_lookup(addr, &symbolsize , &offset,
95 (char **)(&symtab->mod_name), namebuf);
96 if (offset > 8*1024*1024) {
97 symtab->sym_name = NULL;
98 addr = offset = symbolsize = 0;
99 }
100 symtab->sym_start = addr - offset;
101 symtab->sym_end = symtab->sym_start + symbolsize;
102 ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0';
103
104 if (symtab->mod_name == NULL)
105 symtab->mod_name = "kernel";
106 kdb_dbg_printf(AR, "returns %d symtab->sym_start=0x%lx, symtab->mod_name=%px, symtab->sym_name=%px (%s)\n",
107 ret, symtab->sym_start, symtab->mod_name, symtab->sym_name, symtab->sym_name);
108out:
109 return ret;
110}
111
112static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1];
113
114/*
115 * kallsyms_symbol_complete
116 *
117 * Parameters:
118 * prefix_name prefix of a symbol name to lookup
119 * max_len maximum length that can be returned
120 * Returns:
121 * Number of symbols which match the given prefix.
122 * Notes:
123 * prefix_name is changed to contain the longest unique prefix that
124 * starts with this prefix (tab completion).
125 */
126int kallsyms_symbol_complete(char *prefix_name, int max_len)
127{
128 loff_t pos = 0;
129 int prefix_len = strlen(prefix_name), prev_len = 0;
130 int i, number = 0;
131 const char *name;
132
133 while ((name = kdb_walk_kallsyms(&pos))) {
134 if (strncmp(name, prefix_name, prefix_len) == 0) {
135 strscpy(ks_namebuf, name, sizeof(ks_namebuf));
136 /* Work out the longest name that matches the prefix */
137 if (++number == 1) {
138 prev_len = min_t(int, max_len-1,
139 strlen(ks_namebuf));
140 memcpy(ks_namebuf_prev, ks_namebuf, prev_len);
141 ks_namebuf_prev[prev_len] = '\0';
142 continue;
143 }
144 for (i = 0; i < prev_len; i++) {
145 if (ks_namebuf[i] != ks_namebuf_prev[i]) {
146 prev_len = i;
147 ks_namebuf_prev[i] = '\0';
148 break;
149 }
150 }
151 }
152 }
153 if (prev_len > prefix_len)
154 memcpy(prefix_name, ks_namebuf_prev, prev_len+1);
155 return number;
156}
157
158/*
159 * kallsyms_symbol_next
160 *
161 * Parameters:
162 * prefix_name prefix of a symbol name to lookup
163 * flag 0 means search from the head, 1 means continue search.
164 * buf_size maximum length that can be written to prefix_name
165 * buffer
166 * Returns:
167 * 1 if a symbol matches the given prefix.
168 * 0 if no string found
169 */
170int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size)
171{
172 int prefix_len = strlen(prefix_name);
173 static loff_t pos;
174 const char *name;
175
176 if (!flag)
177 pos = 0;
178
179 while ((name = kdb_walk_kallsyms(&pos))) {
180 if (!strncmp(name, prefix_name, prefix_len))
181 return strscpy(prefix_name, name, buf_size);
182 }
183 return 0;
184}
185
186/*
187 * kdb_symbol_print - Standard method for printing a symbol name and offset.
188 * Inputs:
189 * addr Address to be printed.
190 * symtab Address of symbol data, if NULL this routine does its
191 * own lookup.
192 * punc Punctuation for string, bit field.
193 * Remarks:
194 * The string and its punctuation is only printed if the address
195 * is inside the kernel, except that the value is always printed
196 * when requested.
197 */
198void kdb_symbol_print(unsigned long addr, const kdb_symtab_t *symtab_p,
199 unsigned int punc)
200{
201 kdb_symtab_t symtab, *symtab_p2;
202 if (symtab_p) {
203 symtab_p2 = (kdb_symtab_t *)symtab_p;
204 } else {
205 symtab_p2 = &symtab;
206 kdbnearsym(addr, symtab_p2);
207 }
208 if (!(symtab_p2->sym_name || (punc & KDB_SP_VALUE)))
209 return;
210 if (punc & KDB_SP_SPACEB)
211 kdb_printf(" ");
212 if (punc & KDB_SP_VALUE)
213 kdb_printf(kdb_machreg_fmt0, addr);
214 if (symtab_p2->sym_name) {
215 if (punc & KDB_SP_VALUE)
216 kdb_printf(" ");
217 if (punc & KDB_SP_PAREN)
218 kdb_printf("(");
219 if (strcmp(symtab_p2->mod_name, "kernel"))
220 kdb_printf("[%s]", symtab_p2->mod_name);
221 kdb_printf("%s", symtab_p2->sym_name);
222 if (addr != symtab_p2->sym_start)
223 kdb_printf("+0x%lx", addr - symtab_p2->sym_start);
224 if (punc & KDB_SP_SYMSIZE)
225 kdb_printf("/0x%lx",
226 symtab_p2->sym_end - symtab_p2->sym_start);
227 if (punc & KDB_SP_PAREN)
228 kdb_printf(")");
229 }
230 if (punc & KDB_SP_SPACEA)
231 kdb_printf(" ");
232 if (punc & KDB_SP_NEWLINE)
233 kdb_printf("\n");
234}
235
236/*
237 * kdb_strdup - kdb equivalent of strdup, for disasm code.
238 * Inputs:
239 * str The string to duplicate.
240 * type Flags to kmalloc for the new string.
241 * Returns:
242 * Address of the new string, NULL if storage could not be allocated.
243 * Remarks:
244 * This is not in lib/string.c because it uses kmalloc which is not
245 * available when string.o is used in boot loaders.
246 */
247char *kdb_strdup(const char *str, gfp_t type)
248{
249 int n = strlen(str)+1;
250 char *s = kmalloc(n, type);
251 if (!s)
252 return NULL;
253 return strcpy(s, str);
254}
255
256/*
257 * kdb_getarea_size - Read an area of data. The kdb equivalent of
258 * copy_from_user, with kdb messages for invalid addresses.
259 * Inputs:
260 * res Pointer to the area to receive the result.
261 * addr Address of the area to copy.
262 * size Size of the area.
263 * Returns:
264 * 0 for success, < 0 for error.
265 */
266int kdb_getarea_size(void *res, unsigned long addr, size_t size)
267{
268 int ret = copy_from_kernel_nofault((char *)res, (char *)addr, size);
269 if (ret) {
270 if (!KDB_STATE(SUPPRESS)) {
271 kdb_func_printf("Bad address 0x%lx\n", addr);
272 KDB_STATE_SET(SUPPRESS);
273 }
274 ret = KDB_BADADDR;
275 } else {
276 KDB_STATE_CLEAR(SUPPRESS);
277 }
278 return ret;
279}
280
281/*
282 * kdb_putarea_size - Write an area of data. The kdb equivalent of
283 * copy_to_user, with kdb messages for invalid addresses.
284 * Inputs:
285 * addr Address of the area to write to.
286 * res Pointer to the area holding the data.
287 * size Size of the area.
288 * Returns:
289 * 0 for success, < 0 for error.
290 */
291int kdb_putarea_size(unsigned long addr, void *res, size_t size)
292{
293 int ret = copy_to_kernel_nofault((char *)addr, (char *)res, size);
294 if (ret) {
295 if (!KDB_STATE(SUPPRESS)) {
296 kdb_func_printf("Bad address 0x%lx\n", addr);
297 KDB_STATE_SET(SUPPRESS);
298 }
299 ret = KDB_BADADDR;
300 } else {
301 KDB_STATE_CLEAR(SUPPRESS);
302 }
303 return ret;
304}
305
306/*
307 * kdb_getphys - Read data from a physical address. Validate the
308 * address is in range, use kmap_atomic() to get data
309 * similar to kdb_getarea() - but for phys addresses
310 * Inputs:
311 * res Pointer to the word to receive the result
312 * addr Physical address of the area to copy
313 * size Size of the area
314 * Returns:
315 * 0 for success, < 0 for error.
316 */
317static int kdb_getphys(void *res, unsigned long addr, size_t size)
318{
319 unsigned long pfn;
320 void *vaddr;
321 struct page *page;
322
323 pfn = (addr >> PAGE_SHIFT);
324 if (!pfn_valid(pfn))
325 return 1;
326 page = pfn_to_page(pfn);
327 vaddr = kmap_atomic(page);
328 memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size);
329 kunmap_atomic(vaddr);
330
331 return 0;
332}
333
334/*
335 * kdb_getphysword
336 * Inputs:
337 * word Pointer to the word to receive the result.
338 * addr Address of the area to copy.
339 * size Size of the area.
340 * Returns:
341 * 0 for success, < 0 for error.
342 */
343int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
344{
345 int diag;
346 __u8 w1;
347 __u16 w2;
348 __u32 w4;
349 __u64 w8;
350 *word = 0; /* Default value if addr or size is invalid */
351
352 switch (size) {
353 case 1:
354 diag = kdb_getphys(&w1, addr, sizeof(w1));
355 if (!diag)
356 *word = w1;
357 break;
358 case 2:
359 diag = kdb_getphys(&w2, addr, sizeof(w2));
360 if (!diag)
361 *word = w2;
362 break;
363 case 4:
364 diag = kdb_getphys(&w4, addr, sizeof(w4));
365 if (!diag)
366 *word = w4;
367 break;
368 case 8:
369 if (size <= sizeof(*word)) {
370 diag = kdb_getphys(&w8, addr, sizeof(w8));
371 if (!diag)
372 *word = w8;
373 break;
374 }
375 fallthrough;
376 default:
377 diag = KDB_BADWIDTH;
378 kdb_func_printf("bad width %zu\n", size);
379 }
380 return diag;
381}
382
383/*
384 * kdb_getword - Read a binary value. Unlike kdb_getarea, this treats
385 * data as numbers.
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_getword(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 switch (size) {
402 case 1:
403 diag = kdb_getarea(w1, addr);
404 if (!diag)
405 *word = w1;
406 break;
407 case 2:
408 diag = kdb_getarea(w2, addr);
409 if (!diag)
410 *word = w2;
411 break;
412 case 4:
413 diag = kdb_getarea(w4, addr);
414 if (!diag)
415 *word = w4;
416 break;
417 case 8:
418 if (size <= sizeof(*word)) {
419 diag = kdb_getarea(w8, addr);
420 if (!diag)
421 *word = w8;
422 break;
423 }
424 fallthrough;
425 default:
426 diag = KDB_BADWIDTH;
427 kdb_func_printf("bad width %zu\n", size);
428 }
429 return diag;
430}
431
432/*
433 * kdb_putword - Write a binary value. Unlike kdb_putarea, this
434 * treats data as numbers.
435 * Inputs:
436 * addr Address of the area to write to..
437 * word The value to set.
438 * size Size of the area.
439 * Returns:
440 * 0 for success, < 0 for error.
441 */
442int kdb_putword(unsigned long addr, unsigned long word, size_t size)
443{
444 int diag;
445 __u8 w1;
446 __u16 w2;
447 __u32 w4;
448 __u64 w8;
449 switch (size) {
450 case 1:
451 w1 = word;
452 diag = kdb_putarea(addr, w1);
453 break;
454 case 2:
455 w2 = word;
456 diag = kdb_putarea(addr, w2);
457 break;
458 case 4:
459 w4 = word;
460 diag = kdb_putarea(addr, w4);
461 break;
462 case 8:
463 if (size <= sizeof(word)) {
464 w8 = word;
465 diag = kdb_putarea(addr, w8);
466 break;
467 }
468 fallthrough;
469 default:
470 diag = KDB_BADWIDTH;
471 kdb_func_printf("bad width %zu\n", size);
472 }
473 return diag;
474}
475
476
477
478/*
479 * kdb_task_state_char - Return the character that represents the task state.
480 * Inputs:
481 * p struct task for the process
482 * Returns:
483 * One character to represent the task state.
484 */
485char kdb_task_state_char (const struct task_struct *p)
486{
487 unsigned long tmp;
488 char state;
489 int cpu;
490
491 if (!p ||
492 copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
493 return 'E';
494
495 state = task_state_to_char((struct task_struct *) p);
496
497 if (is_idle_task(p)) {
498 /* Idle task. Is it really idle, apart from the kdb
499 * interrupt? */
500 cpu = kdb_process_cpu(p);
501 if (!kdb_task_has_cpu(p) || kgdb_info[cpu].irq_depth == 1) {
502 if (cpu != kdb_initial_cpu)
503 state = '-'; /* idle task */
504 }
505 } else if (!p->mm && strchr("IMS", state)) {
506 state = tolower(state); /* sleeping system daemon */
507 }
508 return state;
509}
510
511/*
512 * kdb_task_state - Return true if a process has the desired state
513 * given by the mask.
514 * Inputs:
515 * p struct task for the process
516 * mask set of characters used to select processes; both NULL
517 * and the empty string mean adopt a default filter, which
518 * is to suppress sleeping system daemons and the idle tasks
519 * Returns:
520 * True if the process matches at least one criteria defined by the mask.
521 */
522bool kdb_task_state(const struct task_struct *p, const char *mask)
523{
524 char state = kdb_task_state_char(p);
525
526 /* If there is no mask, then we will filter code that runs when the
527 * scheduler is idling and any system daemons that are currently
528 * sleeping.
529 */
530 if (!mask || mask[0] == '\0')
531 return !strchr("-ims", state);
532
533 /* A is a special case that matches all states */
534 if (strchr(mask, 'A'))
535 return true;
536
537 return strchr(mask, state);
538}
539
540/* Maintain a small stack of kdb_flags to allow recursion without disturbing
541 * the global kdb state.
542 */
543
544static int kdb_flags_stack[4], kdb_flags_index;
545
546void kdb_save_flags(void)
547{
548 BUG_ON(kdb_flags_index >= ARRAY_SIZE(kdb_flags_stack));
549 kdb_flags_stack[kdb_flags_index++] = kdb_flags;
550}
551
552void kdb_restore_flags(void)
553{
554 BUG_ON(kdb_flags_index <= 0);
555 kdb_flags = kdb_flags_stack[--kdb_flags_index];
556}
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}