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Tighten x86-64 NOP detection.
[ksplice.git] / kmodsrc / ksplice.c
blob4e0d48974ed8171f4ef3ab32466753db34a2d0df
1 /* Copyright (C) 2007-2009 Ksplice, Inc.
2 * Authors: Jeff Arnold, Anders Kaseorg, Tim Abbott
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
15 * 02110-1301, USA.
16 */
17
18 #include <linux/module.h>
19 #include <linux/version.h>
20 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
21 #include <linux/bug.h>
22 #else /* LINUX_VERSION_CODE */
23 /* 7664c5a1da4711bb6383117f51b94c8dc8f3f1cd was after 2.6.19 */
24 #endif /* LINUX_VERSION_CODE */
25 #include <linux/ctype.h>
26 #if defined CONFIG_DEBUG_FS || LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,12)
27 #include <linux/debugfs.h>
28 #else /* CONFIG_DEBUG_FS */
29 /* a7a76cefc4b12bb6508afa4c77f11c2752cc365d was after 2.6.11 */
30 #endif /* CONFIG_DEBUG_FS */
31 #include <linux/errno.h>
32 #include <linux/kallsyms.h>
33 #include <linux/kobject.h>
34 #include <linux/kthread.h>
35 #include <linux/pagemap.h>
36 #include <linux/sched.h>
37 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,12)
38 #include <linux/sort.h>
39 #else /* LINUX_VERSION_CODE < */
40 /* 8c63b6d337534a6b5fb111dc27d0850f535118c0 was after 2.6.11 */
41 #endif /* LINUX_VERSION_CODE */
42 #include <linux/stop_machine.h>
43 #include <linux/sysfs.h>
44 #include <linux/time.h>
45 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
46 #include <linux/uaccess.h>
47 #else /* LINUX_VERSION_CODE < */
48 /* linux/uaccess.h doesn't exist in kernels before 2.6.18 */
49 #include <asm/uaccess.h>
50 #endif /* LINUX_VERSION_CODE */
51 #include <linux/vmalloc.h>
52 #ifdef KSPLICE_STANDALONE
53 #include "ksplice.h"
54 #else /* !KSPLICE_STANDALONE */
55 #include <linux/ksplice.h>
56 #endif /* KSPLICE_STANDALONE */
57 #ifdef KSPLICE_NEED_PARAINSTRUCTIONS
58 #include <asm/alternative.h>
59 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
60
61 #ifdef KSPLICE_STANDALONE
62 #if !defined(CONFIG_KSPLICE) && !defined(CONFIG_KSPLICE_MODULE)
63 #define KSPLICE_NO_KERNEL_SUPPORT 1
64 #endif /* !CONFIG_KSPLICE && !CONFIG_KSPLICE_MODULE */
65
66 #ifndef __used
67 #define __used __attribute_used__
68 #endif
69
70 #define EXTRACT_SYMBOL(sym) \
71 static const typeof(&sym) PASTE(__ksplice_extract_, __LINE__) \
72 __used __attribute__((section(".ksplice_extract"))) = &sym
73 #endif /* KSPLICE_STANDALONE */
74
75 enum stage {
76 STAGE_PREPARING, /* the update is not yet applied */
77 STAGE_APPLIED, /* the update is applied */
78 STAGE_REVERSED, /* the update has been applied and reversed */
79 };
80
81 /* parameter to modify run-pre matching */
82 enum run_pre_mode {
83 RUN_PRE_INITIAL, /* dry run (only change temp_labelvals) */
84 RUN_PRE_DEBUG, /* dry run with byte-by-byte debugging */
85 RUN_PRE_FINAL, /* finalizes the matching */
86 #ifndef CONFIG_FUNCTION_DATA_SECTIONS
87 RUN_PRE_SILENT,
88 #endif /* !CONFIG_FUNCTION_DATA_SECTIONS */
89 };
90
91 enum { NOVAL, TEMP, VAL };
92
93 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,9)
94 /* 5d7b32de9935c65ca8285ac6ec2382afdbb5d479 was after 2.6.8 */
95 #define __bitwise__
96 #elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)
97 /* af4ca457eaf2d6682059c18463eb106e2ce58198 was after 2.6.14 */
98 #define __bitwise__ __bitwise
99 #endif
100
101 typedef int __bitwise__ abort_t;
102
103 #define OK ((__force abort_t) 0)
104 #define NO_MATCH ((__force abort_t) 1)
105 #define CODE_BUSY ((__force abort_t) 2)
106 #define MODULE_BUSY ((__force abort_t) 3)
107 #define OUT_OF_MEMORY ((__force abort_t) 4)
108 #define FAILED_TO_FIND ((__force abort_t) 5)
109 #define ALREADY_REVERSED ((__force abort_t) 6)
110 #define MISSING_EXPORT ((__force abort_t) 7)
111 #define UNEXPECTED_RUNNING_TASK ((__force abort_t) 8)
112 #define UNEXPECTED ((__force abort_t) 9)
113 #define TARGET_NOT_LOADED ((__force abort_t) 10)
114 #define CALL_FAILED ((__force abort_t) 11)
115 #define COLD_UPDATE_LOADED ((__force abort_t) 12)
116 #ifdef KSPLICE_STANDALONE
117 #define BAD_SYSTEM_MAP ((__force abort_t) 13)
118 #endif /* KSPLICE_STANDALONE */
119
120 struct update {
121 const char *kid;
122 const char *name;
123 struct kobject kobj;
124 enum stage stage;
125 abort_t abort_cause;
126 int debug;
127 #ifdef CONFIG_DEBUG_FS
128 struct debugfs_blob_wrapper debug_blob;
129 struct dentry *debugfs_dentry;
130 #else /* !CONFIG_DEBUG_FS */
131 bool debug_continue_line;
132 #endif /* CONFIG_DEBUG_FS */
133 bool partial; /* is it OK if some target mods aren't loaded */
134 struct list_head changes, /* changes for loaded target mods */
135 unused_changes; /* changes for non-loaded target mods */
136 struct list_head conflicts;
137 struct list_head list;
138 struct list_head ksplice_module_list;
139 };
140
141 /* a process conflicting with an update */
142 struct conflict {
143 const char *process_name;
144 pid_t pid;
145 struct list_head stack;
146 struct list_head list;
147 };
148
149 /* an address on the stack of a conflict */
150 struct conflict_addr {
151 unsigned long addr; /* the address on the stack */
152 bool has_conflict; /* does this address in particular conflict? */
153 const char *label; /* the label of the conflicting safety_record */
154 struct list_head list;
155 };
156
157 #if defined(CONFIG_DEBUG_FS) && LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
158 /* Old kernels don't have debugfs_create_blob */
159 struct debugfs_blob_wrapper {
160 void *data;
161 unsigned long size;
162 };
163 #endif /* CONFIG_DEBUG_FS && LINUX_VERSION_CODE */
164
165 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
166 /* 930631edd4b1fe2781d9fe90edbe35d89dfc94cc was after 2.6.18 */
167 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
168 #endif
169
170 struct labelval {
171 struct list_head list;
172 struct ksplice_symbol *symbol;
173 struct list_head *saved_vals;
174 };
175
176 /* region to be checked for conflicts in the stack check */
177 struct safety_record {
178 struct list_head list;
179 const char *label;
180 unsigned long addr; /* the address to be checked for conflicts
181 * (e.g. an obsolete function's starting addr)
182 */
183 unsigned long size; /* the size of the region to be checked */
184 };
185
186 /* possible value for a symbol */
187 struct candidate_val {
188 struct list_head list;
189 unsigned long val;
190 };
191
192 /* private struct used by init_symbol_array */
193 struct ksplice_lookup {
194 /* input */
195 struct ksplice_mod_change *change;
196 struct ksplice_symbol **arr;
197 size_t size;
198 /* output */
199 abort_t ret;
200 };
201
202 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
203 /* c6b37801911d7f4663c99cad8aa230bc934cea82 was after 2.6.29 */
204 struct symsearch {
205 const struct kernel_symbol *start, *stop;
206 const unsigned long *crcs;
207 enum {
208 NOT_GPL_ONLY,
209 GPL_ONLY,
210 WILL_BE_GPL_ONLY,
211 } licence;
212 bool unused;
213 };
214 #endif /* LINUX_VERSION_CODE */
215
216 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
217 /* c33fa9f5609e918824446ef9a75319d4a802f1f4 was after 2.6.25 */
218
219 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
220 /* 2fff0a48416af891dce38fd425246e337831e0bb was after 2.6.19 */
221 static bool virtual_address_mapped(unsigned long addr)
222 {
223 char retval;
224 return probe_kernel_address(addr, retval) != -EFAULT;
225 }
226 #else /* LINUX_VERSION_CODE < */
227 static bool virtual_address_mapped(unsigned long addr);
228 #endif /* LINUX_VERSION_CODE */
229
230 static long probe_kernel_read(void *dst, void *src, size_t size)
231 {
232 if (size == 0)
233 return 0;
234 if (!virtual_address_mapped((unsigned long)src) ||
235 !virtual_address_mapped((unsigned long)src + size - 1))
236 return -EFAULT;
237
238 memcpy(dst, src, size);
239 return 0;
240 }
241 #endif /* LINUX_VERSION_CODE */
242
243 static LIST_HEAD(updates);
244 #ifdef KSPLICE_STANDALONE
245 #if defined(CONFIG_KSPLICE) || defined(CONFIG_KSPLICE_MODULE)
246 extern struct list_head ksplice_modules;
247 #else /* !CONFIG_KSPLICE */
248 LIST_HEAD(ksplice_modules);
249 #endif /* CONFIG_KSPLICE */
250 #else /* !KSPLICE_STANDALONE */
251 LIST_HEAD(ksplice_modules);
252 EXPORT_SYMBOL_GPL(ksplice_modules);
253 static struct kobject *ksplice_kobj;
254 #endif /* KSPLICE_STANDALONE */
255
256 static struct kobj_type update_ktype;
257
258 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,9)
259 /* Old kernels do not have kcalloc
260 * e629946abd0bb8266e9c3d0fd1bff2ef8dec5443 was after 2.6.8
261 */
262 static void *kcalloc(size_t n, size_t size, typeof(GFP_KERNEL) flags)
263 {
264 char *mem;
265 if (n != 0 && size > ULONG_MAX / n)
266 return NULL;
267 mem = kmalloc(n * size, flags);
268 if (mem)
269 memset(mem, 0, n * size);
270 return mem;
271 }
272 #endif /* LINUX_VERSION_CODE */
273
274 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,12)
275 /* 8c63b6d337534a6b5fb111dc27d0850f535118c0 was after 2.6.11 */
276 static void u32_swap(void *a, void *b, int size)
277 {
278 u32 t = *(u32 *)a;
279 *(u32 *)a = *(u32 *)b;
280 *(u32 *)b = t;
281 }
282
283 static void generic_swap(void *a, void *b, int size)
284 {
285 char t;
286
287 do {
288 t = *(char *)a;
289 *(char *)a++ = *(char *)b;
290 *(char *)b++ = t;
291 } while (--size > 0);
292 }
293
294 /**
295 * sort - sort an array of elements
296 * @base: pointer to data to sort
297 * @num: number of elements
298 * @size: size of each element
299 * @cmp: pointer to comparison function
300 * @swap: pointer to swap function or NULL
301 *
302 * This function does a heapsort on the given array. You may provide a
303 * swap function optimized to your element type.
304 *
305 * Sorting time is O(n log n) both on average and worst-case. While
306 * qsort is about 20% faster on average, it suffers from exploitable
307 * O(n*n) worst-case behavior and extra memory requirements that make
308 * it less suitable for kernel use.
309 */
310
311 void sort(void *base, size_t num, size_t size,
312 int (*cmp)(const void *, const void *),
313 void (*swap)(void *, void *, int size))
314 {
315 /* pre-scale counters for performance */
316 int i = (num / 2 - 1) * size, n = num * size, c, r;
317
318 if (!swap)
319 swap = (size == 4 ? u32_swap : generic_swap);
320
321 /* heapify */
322 for (; i >= 0; i -= size) {
323 for (r = i; r * 2 + size < n; r = c) {
324 c = r * 2 + size;
325 if (c < n - size && cmp(base + c, base + c + size) < 0)
326 c += size;
327 if (cmp(base + r, base + c) >= 0)
328 break;
329 swap(base + r, base + c, size);
330 }
331 }
332
333 /* sort */
334 for (i = n - size; i > 0; i -= size) {
335 swap(base, base + i, size);
336 for (r = 0; r * 2 + size < i; r = c) {
337 c = r * 2 + size;
338 if (c < i - size && cmp(base + c, base + c + size) < 0)
339 c += size;
340 if (cmp(base + r, base + c) >= 0)
341 break;
342 swap(base + r, base + c, size);
343 }
344 }
345 }
346 #endif /* LINUX_VERSION_CODE < */
347
348 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,13)
349 /* Old kernels do not have kstrdup
350 * 543537bd922692bc978e2e356fcd8bfc9c2ee7d5 was after 2.6.12
351 */
352 #define kstrdup ksplice_kstrdup
353 static char *kstrdup(const char *s, typeof(GFP_KERNEL) gfp)
354 {
355 size_t len;
356 char *buf;
357
358 if (!s)
359 return NULL;
360
361 len = strlen(s) + 1;
362 buf = kmalloc(len, gfp);
363 if (buf)
364 memcpy(buf, s, len);
365 return buf;
366 }
367 #endif /* LINUX_VERSION_CODE */
368
369 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
370 /* Old kernels use semaphore instead of mutex
371 * 97d1f15b7ef52c1e9c28dc48b454024bb53a5fd2 was after 2.6.16
372 */
373 #define mutex semaphore
374 #define mutex_lock down
375 #define mutex_unlock up
376 #endif /* LINUX_VERSION_CODE */
377
378 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
379 /* 11443ec7d9286dd25663516436a14edfb5f43857 was after 2.6.21 */
380 static char * __attribute_used__
381 kvasprintf(typeof(GFP_KERNEL) gfp, const char *fmt, va_list ap)
382 {
383 unsigned int len;
384 char *p, dummy[1];
385 va_list aq;
386
387 va_copy(aq, ap);
388 len = vsnprintf(dummy, 0, fmt, aq);
389 va_end(aq);
390
391 p = kmalloc(len + 1, gfp);
392 if (!p)
393 return NULL;
394
395 vsnprintf(p, len + 1, fmt, ap);
396
397 return p;
398 }
399 #endif
400
401 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18)
402 /* e905914f96e11862b130dd229f73045dad9a34e8 was after 2.6.17 */
403 static char * __attribute__((format (printf, 2, 3)))
404 kasprintf(typeof(GFP_KERNEL) gfp, const char *fmt, ...)
405 {
406 va_list ap;
407 char *p;
408
409 va_start(ap, fmt);
410 p = kvasprintf(gfp, fmt, ap);
411 va_end(ap);
412
413 return p;
414 }
415 #endif
416
417 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
418 /* 06b2a76d25d3cfbd14680021c1d356c91be6904e was after 2.6.24 */
419 static int strict_strtoul(const char *cp, unsigned int base, unsigned long *res)
420 {
421 char *tail;
422 unsigned long val;
423 size_t len;
424
425 *res = 0;
426 len = strlen(cp);
427 if (len == 0)
428 return -EINVAL;
429
430 val = simple_strtoul(cp, &tail, base);
431 if ((*tail == '\0') ||
432 ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
433 *res = val;
434 return 0;
435 }
436
437 return -EINVAL;
438 }
439 #endif
440
441 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
442 /* 9b1a4d38373a5581a4e01032a3ccdd94cd93477b was after 2.6.26 */
443 /* Assume cpus == NULL. */
444 #define stop_machine(fn, data, cpus) stop_machine_run(fn, data, NR_CPUS);
445 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
446 /* ee527cd3a20c2aeaac17d939e5d011f7a76d69f5 was after 2.6.21 */
447 EXTRACT_SYMBOL(stop_machine_run);
448 #endif /* LINUX_VERSION_CODE */
449 #endif /* LINUX_VERSION_CODE */
450
451 #ifndef task_thread_info
452 #define task_thread_info(task) (task)->thread_info
453 #endif /* !task_thread_info */
454
455 #ifdef KSPLICE_STANDALONE
456
457 #ifdef do_each_thread_ve /* OpenVZ kernels define this */
458 #define do_each_thread do_each_thread_all
459 #define while_each_thread while_each_thread_all
460 #endif
461
462 static bool bootstrapped = false;
463
464 /* defined by ksplice-create */
465 extern const struct ksplice_reloc ksplice_init_relocs[],
466 ksplice_init_relocs_end[];
467
468 #endif /* KSPLICE_STANDALONE */
469
470 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
471 /* c6b37801911d7f4663c99cad8aa230bc934cea82 was after 2.6.29 */
472 extern struct list_head modules;
473 EXTRACT_SYMBOL(modules);
474 extern struct mutex module_mutex;
475 EXTRACT_SYMBOL(module_mutex);
476 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18) && defined(CONFIG_UNUSED_SYMBOLS)
477 /* f71d20e961474dde77e6558396efb93d6ac80a4b was after 2.6.17 */
478 #define KSPLICE_KSYMTAB_UNUSED_SUPPORT 1
479 #endif /* LINUX_VERSION_CODE */
480 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
481 /* 9f28bb7e1d0188a993403ab39b774785892805e1 was after 2.6.16 */
482 #define KSPLICE_KSYMTAB_FUTURE_SUPPORT 1
483 #endif /* LINUX_VERSION_CODE */
484 extern const struct kernel_symbol __start___ksymtab[];
485 EXTRACT_SYMBOL(__start___ksymtab);
486 extern const struct kernel_symbol __stop___ksymtab[];
487 EXTRACT_SYMBOL(__stop___ksymtab);
488 extern const unsigned long __start___kcrctab[];
489 EXTRACT_SYMBOL(__start___kcrctab);
490 extern const struct kernel_symbol __start___ksymtab_gpl[];
491 EXTRACT_SYMBOL(__start___ksymtab_gpl);
492 extern const struct kernel_symbol __stop___ksymtab_gpl[];
493 EXTRACT_SYMBOL(__stop___ksymtab_gpl);
494 extern const unsigned long __start___kcrctab_gpl[];
495 EXTRACT_SYMBOL(__start___kcrctab_gpl);
496 #ifdef KSPLICE_KSYMTAB_UNUSED_SUPPORT
497 extern const struct kernel_symbol __start___ksymtab_unused[];
498 EXTRACT_SYMBOL(__start___ksymtab_unused);
499 extern const struct kernel_symbol __stop___ksymtab_unused[];
500 EXTRACT_SYMBOL(__stop___ksymtab_unused);
501 extern const unsigned long __start___kcrctab_unused[];
502 EXTRACT_SYMBOL(__start___kcrctab_unused);
503 extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
504 EXTRACT_SYMBOL(__start___ksymtab_unused_gpl);
505 extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
506 EXTRACT_SYMBOL(__stop___ksymtab_unused_gpl);
507 extern const unsigned long __start___kcrctab_unused_gpl[];
508 EXTRACT_SYMBOL(__start___kcrctab_unused_gpl);
509 #endif /* KSPLICE_KSYMTAB_UNUSED_SUPPORT */
510 #ifdef KSPLICE_KSYMTAB_FUTURE_SUPPORT
511 extern const struct kernel_symbol __start___ksymtab_gpl_future[];
512 EXTRACT_SYMBOL(__start___ksymtab_gpl_future);
513 extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
514 EXTRACT_SYMBOL(__stop___ksymtab_gpl_future);
515 extern const unsigned long __start___kcrctab_gpl_future[];
516 EXTRACT_SYMBOL(__start___kcrctab_gpl_future);
517 #endif /* KSPLICE_KSYMTAB_FUTURE_SUPPORT */
518 #endif /* LINUX_VERSION_CODE */
519
520 static struct update *init_ksplice_update(const char *kid);
521 static void cleanup_ksplice_update(struct update *update);
522 static void maybe_cleanup_ksplice_update(struct update *update);
523 static void add_to_update(struct ksplice_mod_change *change,
524 struct update *update);
525 static int ksplice_sysfs_init(struct update *update);
526
527 /* Preparing the relocations and patches for application */
528 static abort_t apply_update(struct update *update);
529 static abort_t reverse_update(struct update *update);
530 static abort_t prepare_change(struct ksplice_mod_change *change);
531 static abort_t finalize_change(struct ksplice_mod_change *change);
532 static abort_t finalize_patches(struct ksplice_mod_change *change);
533 static abort_t add_dependency_on_address(struct ksplice_mod_change *change,
534 unsigned long addr);
535 static abort_t map_trampoline_pages(struct update *update);
536 static void unmap_trampoline_pages(struct update *update);
537 static void *map_writable(void *addr, size_t len);
538 static abort_t apply_relocs(struct ksplice_mod_change *change,
539 const struct ksplice_reloc *relocs,
540 const struct ksplice_reloc *relocs_end);
541 static abort_t apply_reloc(struct ksplice_mod_change *change,
542 const struct ksplice_reloc *r);
543 static abort_t apply_howto_reloc(struct ksplice_mod_change *change,
544 const struct ksplice_reloc *r);
545 static abort_t apply_howto_date(struct ksplice_mod_change *change,
546 const struct ksplice_reloc *r);
547 static abort_t read_reloc_value(struct ksplice_mod_change *change,
548 const struct ksplice_reloc *r,
549 unsigned long addr, unsigned long *valp);
550 static abort_t write_reloc_value(struct ksplice_mod_change *change,
551 const struct ksplice_reloc *r,
552 unsigned long addr, unsigned long sym_addr);
553 static abort_t create_module_list_entry(struct ksplice_mod_change *change,
554 bool to_be_applied);
555 static void cleanup_module_list_entries(struct update *update);
556 static void __attribute__((noreturn)) ksplice_deleted(void);
557
558 /* run-pre matching */
559 static abort_t match_change_sections(struct ksplice_mod_change *change,
560 bool consider_data_sections);
561 static abort_t find_section(struct ksplice_mod_change *change,
562 struct ksplice_section *sect);
563 static abort_t try_addr(struct ksplice_mod_change *change,
564 struct ksplice_section *sect,
565 unsigned long run_addr,
566 struct list_head *safety_records,
567 enum run_pre_mode mode);
568 static abort_t run_pre_cmp(struct ksplice_mod_change *change,
569 const struct ksplice_section *sect,
570 unsigned long run_addr,
571 struct list_head *safety_records,
572 enum run_pre_mode mode);
573 #ifndef CONFIG_FUNCTION_DATA_SECTIONS
574 /* defined in arch/ARCH/kernel/ksplice-arch.c */
575 static abort_t arch_run_pre_cmp(struct ksplice_mod_change *change,
576 struct ksplice_section *sect,
577 unsigned long run_addr,
578 struct list_head *safety_records,
579 enum run_pre_mode mode);
580 #endif /* CONFIG_FUNCTION_DATA_SECTIONS */
581 static void print_bytes(struct ksplice_mod_change *change,
582 const unsigned char *run, int runc,
583 const unsigned char *pre, int prec);
584 #if defined(KSPLICE_STANDALONE) && !defined(CONFIG_KALLSYMS)
585 static abort_t brute_search(struct ksplice_mod_change *change,
586 struct ksplice_section *sect,
587 const void *start, unsigned long len,
588 struct list_head *vals);
589 static abort_t brute_search_all(struct ksplice_mod_change *change,
590 struct ksplice_section *sect,
591 struct list_head *vals);
592 #endif /* KSPLICE_STANDALONE && !CONFIG_KALLSYMS */
593 static const struct ksplice_reloc *
594 init_reloc_search(struct ksplice_mod_change *change,
595 const struct ksplice_section *sect);
596 static const struct ksplice_reloc *find_reloc(const struct ksplice_reloc *start,
597 const struct ksplice_reloc *end,
598 unsigned long address,
599 unsigned long size);
600 static abort_t lookup_reloc(struct ksplice_mod_change *change,
601 const struct ksplice_reloc **fingerp,
602 unsigned long addr,
603 const struct ksplice_reloc **relocp);
604 static abort_t handle_reloc(struct ksplice_mod_change *change,
605 const struct ksplice_section *sect,
606 const struct ksplice_reloc *r,
607 unsigned long run_addr, enum run_pre_mode mode);
608 static abort_t handle_howto_date(struct ksplice_mod_change *change,
609 const struct ksplice_section *sect,
610 const struct ksplice_reloc *r,
611 unsigned long run_addr,
612 enum run_pre_mode mode);
613 static abort_t handle_howto_reloc(struct ksplice_mod_change *change,
614 const struct ksplice_section *sect,
615 const struct ksplice_reloc *r,
616 unsigned long run_addr,
617 enum run_pre_mode mode);
618 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
619 #ifdef CONFIG_BUG
620 static abort_t handle_bug(struct ksplice_mod_change *change,
621 const struct ksplice_reloc *r,
622 unsigned long run_addr);
623 #endif /* CONFIG_BUG */
624 #else /* LINUX_VERSION_CODE < */
625 /* 7664c5a1da4711bb6383117f51b94c8dc8f3f1cd was after 2.6.19 */
626 #endif /* LINUX_VERSION_CODE */
627 static abort_t handle_extable(struct ksplice_mod_change *change,
628 const struct ksplice_reloc *r,
629 unsigned long run_addr);
630 static struct ksplice_section *symbol_section(struct ksplice_mod_change *change,
631 const struct ksplice_symbol *sym);
632 static int compare_section_labels(const void *va, const void *vb);
633 static int symbol_section_bsearch_compare(const void *a, const void *b);
634 static const struct ksplice_reloc *
635 patch_reloc(struct ksplice_mod_change *change,
636 const struct ksplice_patch *p);
637
638 /* Computing possible addresses for symbols */
639 static abort_t lookup_symbol(struct ksplice_mod_change *change,
640 const struct ksplice_symbol *ksym,
641 struct list_head *vals);
642 static void cleanup_symbol_arrays(struct ksplice_mod_change *change);
643 static abort_t init_symbol_arrays(struct ksplice_mod_change *change);
644 static abort_t init_symbol_array(struct ksplice_mod_change *change,
645 struct ksplice_symbol *start,
646 struct ksplice_symbol *end);
647 static abort_t uniquify_symbols(struct ksplice_mod_change *change);
648 static abort_t add_matching_values(struct ksplice_lookup *lookup,
649 const char *sym_name, unsigned long sym_val);
650 static bool add_export_values(const struct symsearch *syms,
651 struct module *owner,
652 unsigned int symnum, void *data);
653 static int symbolp_bsearch_compare(const void *key, const void *elt);
654 static int compare_symbolp_names(const void *a, const void *b);
655 static int compare_symbolp_labels(const void *a, const void *b);
656 #ifdef CONFIG_KALLSYMS
657 static int add_kallsyms_values(void *data, const char *name,
658 struct module *owner, unsigned long val);
659 #endif /* CONFIG_KALLSYMS */
660 #ifdef KSPLICE_STANDALONE
661 static abort_t
662 add_system_map_candidates(struct ksplice_mod_change *change,
663 const struct ksplice_system_map *start,
664 const struct ksplice_system_map *end,
665 const char *label, struct list_head *vals);
666 static int compare_system_map(const void *a, const void *b);
667 static int system_map_bsearch_compare(const void *key, const void *elt);
668 #endif /* KSPLICE_STANDALONE */
669 static abort_t new_export_lookup(struct ksplice_mod_change *ichange,
670 const char *name, struct list_head *vals);
671
672 /* Atomic update trampoline insertion and removal */
673 static abort_t patch_action(struct update *update, enum ksplice_action action);
674 static int __apply_patches(void *update);
675 static int __reverse_patches(void *update);
676 static abort_t check_each_task(struct update *update);
677 static abort_t check_task(struct update *update,
678 const struct task_struct *t, bool rerun);
679 static abort_t check_stack(struct update *update, struct conflict *conf,
680 const struct thread_info *tinfo,
681 const unsigned long *stack);
682 static abort_t check_address(struct update *update,
683 struct conflict *conf, unsigned long addr);
684 static abort_t check_record(struct conflict_addr *ca,
685 const struct safety_record *rec,
686 unsigned long addr);
687 static bool is_stop_machine(const struct task_struct *t);
688 static void cleanup_conflicts(struct update *update);
689 static void print_conflicts(struct update *update);
690 static void insert_trampoline(struct ksplice_patch *p);
691 static abort_t verify_trampoline(struct ksplice_mod_change *change,
692 const struct ksplice_patch *p);
693 static void remove_trampoline(const struct ksplice_patch *p);
694
695 static abort_t create_labelval(struct ksplice_mod_change *change,
696 struct ksplice_symbol *ksym,
697 unsigned long val, int status);
698 static abort_t create_safety_record(struct ksplice_mod_change *change,
699 const struct ksplice_section *sect,
700 struct list_head *record_list,
701 unsigned long run_addr,
702 unsigned long run_size);
703 static abort_t add_candidate_val(struct ksplice_mod_change *change,
704 struct list_head *vals, unsigned long val);
705 static void release_vals(struct list_head *vals);
706 static void set_temp_labelvals(struct ksplice_mod_change *change, int status);
707
708 static int contains_canary(struct ksplice_mod_change *change,
709 unsigned long blank_addr,
710 const struct ksplice_reloc_howto *howto);
711 static unsigned long follow_trampolines(struct ksplice_mod_change *change,
712 unsigned long addr);
713 static bool patches_module(const struct module *a, const struct module *b);
714 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
715 /* 66f92cf9d415e96a5bdd6c64de8dd8418595d2fc was after 2.6.29 */
716 static bool strstarts(const char *str, const char *prefix);
717 #endif /* LINUX_VERSION_CODE */
718 static bool singular(struct list_head *list);
719 static void *bsearch(const void *key, const void *base, size_t n,
720 size_t size, int (*cmp)(const void *key, const void *elt));
721 static int compare_relocs(const void *a, const void *b);
722 static int reloc_bsearch_compare(const void *key, const void *elt);
723
724 /* Debugging */
725 static abort_t init_debug_buf(struct update *update);
726 static void clear_debug_buf(struct update *update);
727 static int __attribute__((format(printf, 2, 3)))
728 _ksdebug(struct update *update, const char *fmt, ...);
729 #define ksdebug(change, fmt, ...) \
730 _ksdebug(change->update, fmt, ## __VA_ARGS__)
731
732 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30) && defined(CONFIG_KALLSYMS)
733 /* 75a66614db21007bcc8c37f9c5d5b922981387b9 was after 2.6.29 */
734 static int kallsyms_on_each_symbol(int (*fn)(void *, const char *,
735 struct module *, unsigned long),
736 void *data);
737 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
738 static unsigned int kallsyms_expand_symbol(unsigned int off, char *result);
739 #endif /* LINUX_VERSION_CODE */
740 static int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
741 struct module *,
742 unsigned long),
743 void *data);
744 #endif /* LINUX_VERSION_CODE && CONFIG_KALLSYMS */
745
746 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
747 /* c6b37801911d7f4663c99cad8aa230bc934cea82 was after 2.6.29 */
748 static struct module *find_module(const char *name);
749 static int use_module(struct module *a, struct module *b);
750 static const struct kernel_symbol *find_symbol(const char *name,
751 struct module **owner,
752 const unsigned long **crc,
753 bool gplok, bool warn);
754 static bool each_symbol(bool (*fn)(const struct symsearch *arr,
755 struct module *owner,
756 unsigned int symnum, void *data),
757 void *data);
758 static struct module *__module_address(unsigned long addr);
759 #endif /* LINUX_VERSION_CODE */
760
761 /* Architecture-specific functions defined in arch/ARCH/kernel/ksplice-arch.c */
762
763 /* Prepare a trampoline for the given patch */
764 static abort_t prepare_trampoline(struct ksplice_mod_change *change,
765 struct ksplice_patch *p);
766 /* What address does the trampoline at addr jump to? */
767 static abort_t trampoline_target(struct ksplice_mod_change *change,
768 unsigned long addr, unsigned long *new_addr);
769 /* Hook to handle pc-relative jumps inserted by parainstructions */
770 static abort_t handle_paravirt(struct ksplice_mod_change *change,
771 unsigned long pre, unsigned long run,
772 int *matched);
773 /* Is address p on the stack of the given thread? */
774 static bool valid_stack_ptr(const struct thread_info *tinfo, const void *p);
775
776 #ifndef KSPLICE_STANDALONE
777 #include "ksplice-arch.c"
778 #elif defined CONFIG_X86
779 #include "x86/ksplice-arch.c"
780 #elif defined CONFIG_ARM
781 #include "arm/ksplice-arch.c"
782 #endif /* KSPLICE_STANDALONE */
783
784 #define clear_list(head, type, member) \
785 do { \
786 struct list_head *_pos, *_n; \
787 list_for_each_safe(_pos, _n, head) { \
788 list_del(_pos); \
789 kfree(list_entry(_pos, type, member)); \
790 } \
791 } while (0)
792
793 /**
794 * init_ksplice_mod_change() - Initializes a ksplice change
795 * @change: The change to be initialized. All of the public fields of the
796 * change and its associated data structures should be populated
797 * before this function is called. The values of the private
798 * fields will be ignored.
799 **/
800 int init_ksplice_mod_change(struct ksplice_mod_change *change)
801 {
802 struct update *update;
803 struct ksplice_patch *p;
804 struct ksplice_section *s;
805 int ret = 0;
806
807 #ifdef KSPLICE_STANDALONE
808 if (!bootstrapped)
809 return -1;
810 #endif /* KSPLICE_STANDALONE */
811
812 INIT_LIST_HEAD(&change->temp_labelvals);
813 INIT_LIST_HEAD(&change->safety_records);
814
815 sort(change->old_code.relocs,
816 change->old_code.relocs_end - change->old_code.relocs,
817 sizeof(*change->old_code.relocs), compare_relocs, NULL);
818 sort(change->new_code.relocs,
819 change->new_code.relocs_end - change->new_code.relocs,
820 sizeof(*change->new_code.relocs), compare_relocs, NULL);
821 sort(change->old_code.sections,
822 change->old_code.sections_end - change->old_code.sections,
823 sizeof(*change->old_code.sections), compare_section_labels, NULL);
824 #ifdef KSPLICE_STANDALONE
825 sort(change->new_code.system_map,
826 change->new_code.system_map_end - change->new_code.system_map,
827 sizeof(*change->new_code.system_map), compare_system_map, NULL);
828 sort(change->old_code.system_map,
829 change->old_code.system_map_end - change->old_code.system_map,
830 sizeof(*change->old_code.system_map), compare_system_map, NULL);
831 #endif /* KSPLICE_STANDALONE */
832
833 for (p = change->patches; p < change->patches_end; p++)
834 p->vaddr = NULL;
835 for (s = change->old_code.sections; s < change->old_code.sections_end;
836 s++)
837 s->match_map = NULL;
838 for (p = change->patches; p < change->patches_end; p++) {
839 const struct ksplice_reloc *r = patch_reloc(change, p);
840 if (r == NULL)
841 return -ENOENT;
842 if (p->type == KSPLICE_PATCH_DATA) {
843 s = symbol_section(change, r->symbol);
844 if (s == NULL)
845 return -ENOENT;
846 /* Ksplice creates KSPLICE_PATCH_DATA patches in order
847 * to modify rodata sections that have been explicitly
848 * marked for patching using the ksplice-patch.h macro
849 * ksplice_assume_rodata. Here we modify the section
850 * flags appropriately.
851 */
852 if (s->flags & KSPLICE_SECTION_DATA)
853 s->flags = (s->flags & ~KSPLICE_SECTION_DATA) |
854 KSPLICE_SECTION_RODATA;
855 }
856 }
857
858 mutex_lock(&module_mutex);
859 list_for_each_entry(update, &updates, list) {
860 if (strcmp(change->kid, update->kid) == 0) {
861 if (update->stage != STAGE_PREPARING) {
862 ret = -EPERM;
863 goto out;
864 }
865 add_to_update(change, update);
866 ret = 0;
867 goto out;
868 }
869 }
870 update = init_ksplice_update(change->kid);
871 if (update == NULL) {
872 ret = -ENOMEM;
873 goto out;
874 }
875 ret = ksplice_sysfs_init(update);
876 if (ret != 0) {
877 cleanup_ksplice_update(update);
878 goto out;
879 }
880 add_to_update(change, update);
881 out:
882 mutex_unlock(&module_mutex);
883 return ret;
884 }
885 EXPORT_SYMBOL_GPL(init_ksplice_mod_change);
886
887 /**
888 * cleanup_ksplice_mod_change() - Cleans up a change if appropriate
889 * @change: The change to be cleaned up
890 *
891 * cleanup_ksplice_mod_change is ordinarily called twice for each
892 * Ksplice update: once when the old_code module is unloaded, and once
893 * when the new_code module is unloaded. By freeing what can be freed
894 * on each unload, we avoid leaks even in unusual scenarios, e.g. if
895 * several alternative old_code modules are loaded and unloaded
896 * successively.
897 */
898 void cleanup_ksplice_mod_change(struct ksplice_mod_change *change)
899 {
900 if (change->update == NULL)
901 return;
902
903 mutex_lock(&module_mutex);
904 if (change->update->stage == STAGE_APPLIED) {
905 struct ksplice_mod_change *c;
906 bool found = false;
907
908 list_for_each_entry(c, &change->update->unused_changes, list) {
909 if (c == change)
910 found = true;
911 }
912 if (found)
913 list_del(&change->list);
914 mutex_unlock(&module_mutex);
915 return;
916 }
917 list_del(&change->list);
918 if (change->update->stage == STAGE_PREPARING)
919 maybe_cleanup_ksplice_update(change->update);
920 change->update = NULL;
921 mutex_unlock(&module_mutex);
922 }
923 EXPORT_SYMBOL_GPL(cleanup_ksplice_mod_change);
924
925 static struct update *init_ksplice_update(const char *kid)
926 {
927 struct update *update;
928 update = kcalloc(1, sizeof(struct update), GFP_KERNEL);
929 if (update == NULL)
930 return NULL;
931 update->name = kasprintf(GFP_KERNEL, "ksplice_%s", kid);
932 if (update->name == NULL) {
933 kfree(update);
934 return NULL;
935 }
936 update->kid = kstrdup(kid, GFP_KERNEL);
937 if (update->kid == NULL) {
938 kfree(update->name);
939 kfree(update);
940 return NULL;
941 }
942 if (try_module_get(THIS_MODULE) != 1) {
943 kfree(update->kid);
944 kfree(update->name);
945 kfree(update);
946 return NULL;
947 }
948 INIT_LIST_HEAD(&update->changes);
949 INIT_LIST_HEAD(&update->unused_changes);
950 INIT_LIST_HEAD(&update->ksplice_module_list);
951 if (init_debug_buf(update) != OK) {
952 module_put(THIS_MODULE);
953 kfree(update->kid);
954 kfree(update->name);
955 kfree(update);
956 return NULL;
957 }
958 list_add(&update->list, &updates);
959 update->stage = STAGE_PREPARING;
960 update->abort_cause = OK;
961 update->partial = 0;
962 INIT_LIST_HEAD(&update->conflicts);
963 return update;
964 }
965
966 static void cleanup_ksplice_update(struct update *update)
967 {
968 list_del(&update->list);
969 cleanup_conflicts(update);
970 clear_debug_buf(update);
971 cleanup_module_list_entries(update);
972 kfree(update->kid);
973 kfree(update->name);
974 kfree(update);
975 module_put(THIS_MODULE);
976 }
977
978 /* Clean up the update if it no longer has any changes */
979 static void maybe_cleanup_ksplice_update(struct update *update)
980 {
981 if (list_empty(&update->changes) && list_empty(&update->unused_changes))
982 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
983 kobject_put(&update->kobj);
984 #else /* LINUX_VERSION_CODE < */
985 /* 6d06adfaf82d154023141ddc0c9de18b6a49090b was after 2.6.24 */
986 kobject_unregister(&update->kobj);
987 #endif /* LINUX_VERSION_CODE */
988 }
989
990 static void add_to_update(struct ksplice_mod_change *change,
991 struct update *update)
992 {
993 change->update = update;
994 list_add(&change->list, &update->unused_changes);
995 }
996
997 static int ksplice_sysfs_init(struct update *update)
998 {
999 int ret = 0;
1000 memset(&update->kobj, 0, sizeof(update->kobj));
1001 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
1002 #ifndef KSPLICE_STANDALONE
1003 ret = kobject_init_and_add(&update->kobj, &update_ktype,
1004 ksplice_kobj, "%s", update->kid);
1005 #else /* KSPLICE_STANDALONE */
1006 ret = kobject_init_and_add(&update->kobj, &update_ktype,
1007 &THIS_MODULE->mkobj.kobj, "ksplice");
1008 #endif /* KSPLICE_STANDALONE */
1009 #else /* LINUX_VERSION_CODE < */
1010 /* 6d06adfaf82d154023141ddc0c9de18b6a49090b was after 2.6.24 */
1011 ret = kobject_set_name(&update->kobj, "%s", "ksplice");
1012 if (ret != 0)
1013 return ret;
1014 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,11)
1015 update->kobj.parent = &THIS_MODULE->mkobj.kobj;
1016 #else /* LINUX_VERSION_CODE < */
1017 /* b86ab02803095190d6b72bcc18dcf620bf378df9 was after 2.6.10 */
1018 update->kobj.parent = &THIS_MODULE->mkobj->kobj;
1019 #endif /* LINUX_VERSION_CODE */
1020 update->kobj.ktype = &update_ktype;
1021 ret = kobject_register(&update->kobj);
1022 #endif /* LINUX_VERSION_CODE */
1023 if (ret != 0)
1024 return ret;
1025 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,15)
1026 kobject_uevent(&update->kobj, KOBJ_ADD);
1027 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
1028 /* 312c004d36ce6c739512bac83b452f4c20ab1f62 was after 2.6.14 */
1029 /* 12025235884570ba7f02a6f427f973ac6be7ec54 was after 2.6.9 */
1030 kobject_uevent(&update->kobj, KOBJ_ADD, NULL);
1031 #endif /* LINUX_VERSION_CODE */
1032 return 0;
1033 }
1034
1035 #ifdef KSPLICE_NEED_PARAINSTRUCTIONS
1036 EXTRACT_SYMBOL(apply_paravirt);
1037 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
1038
1039 static abort_t apply_update(struct update *update)
1040 {
1041 struct ksplice_mod_change *change, *n;
1042 abort_t ret;
1043 int retval;
1044
1045 list_for_each_entry(change, &update->changes, list) {
1046 ret = create_module_list_entry(change, true);
1047 if (ret != OK)
1048 goto out;
1049 }
1050
1051 list_for_each_entry_safe(change, n, &update->unused_changes, list) {
1052 if (strcmp(change->target_name, "vmlinux") == 0) {
1053 change->target = NULL;
1054 } else if (change->target == NULL) {
1055 change->target = find_module(change->target_name);
1056 if (change->target == NULL ||
1057 !module_is_live(change->target)) {
1058 if (!update->partial) {
1059 ret = TARGET_NOT_LOADED;
1060 goto out;
1061 }
1062 ret = create_module_list_entry(change, false);
1063 if (ret != OK)
1064 goto out;
1065 continue;
1066 }
1067 retval = use_module(change->new_code_mod,
1068 change->target);
1069 if (retval != 1) {
1070 ret = UNEXPECTED;
1071 goto out;
1072 }
1073 }
1074 ret = create_module_list_entry(change, true);
1075 if (ret != OK)
1076 goto out;
1077 list_del(&change->list);
1078 list_add_tail(&change->list, &update->changes);
1079
1080 #ifdef KSPLICE_NEED_PARAINSTRUCTIONS
1081 if (change->target == NULL) {
1082 apply_paravirt(change->new_code.parainstructions,
1083 change->new_code.parainstructions_end);
1084 apply_paravirt(change->old_code.parainstructions,
1085 change->old_code.parainstructions_end);
1086 }
1087 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
1088 }
1089
1090 list_for_each_entry(change, &update->changes, list) {
1091 const struct ksplice_section *sect;
1092 for (sect = change->new_code.sections;
1093 sect < change->new_code.sections_end; sect++) {
1094 struct safety_record *rec = kmalloc(sizeof(*rec),
1095 GFP_KERNEL);
1096 if (rec == NULL) {
1097 ret = OUT_OF_MEMORY;
1098 goto out;
1099 }
1100 rec->addr = sect->address;
1101 rec->size = sect->size;
1102 rec->label = sect->symbol->label;
1103 list_add(&rec->list, &change->safety_records);
1104 }
1105 }
1106
1107 list_for_each_entry(change, &update->changes, list) {
1108 ret = init_symbol_arrays(change);
1109 if (ret != OK) {
1110 cleanup_symbol_arrays(change);
1111 goto out;
1112 }
1113 ret = prepare_change(change);
1114 cleanup_symbol_arrays(change);
1115 if (ret != OK)
1116 goto out;
1117 }
1118 ret = patch_action(update, KS_APPLY);
1119 out:
1120 list_for_each_entry(change, &update->changes, list) {
1121 struct ksplice_section *s;
1122 if (update->stage == STAGE_PREPARING)
1123 clear_list(&change->safety_records,
1124 struct safety_record, list);
1125 for (s = change->old_code.sections;
1126 s < change->old_code.sections_end; s++) {
1127 if (s->match_map != NULL) {
1128 vfree(s->match_map);
1129 s->match_map = NULL;
1130 }
1131 }
1132 }
1133 if (update->stage == STAGE_PREPARING)
1134 cleanup_module_list_entries(update);
1135
1136 if (ret == OK)
1137 printk(KERN_INFO "ksplice: Update %s applied successfully\n",
1138 update->kid);
1139 return ret;
1140 }
1141
1142 static abort_t reverse_update(struct update *update)
1143 {
1144 abort_t ret;
1145 struct ksplice_mod_change *change;
1146
1147 clear_debug_buf(update);
1148 ret = init_debug_buf(update);
1149 if (ret != OK)
1150 return ret;
1151
1152 _ksdebug(update, "Preparing to reverse %s\n", update->kid);
1153
1154 ret = patch_action(update, KS_REVERSE);
1155 if (ret != OK)
1156 return ret;
1157
1158 list_for_each_entry(change, &update->changes, list)
1159 clear_list(&change->safety_records, struct safety_record, list);
1160
1161 printk(KERN_INFO "ksplice: Update %s reversed successfully\n",
1162 update->kid);
1163 return OK;
1164 }
1165
1166 static int compare_symbolp_names(const void *a, const void *b)
1167 {
1168 const struct ksplice_symbol *const *sympa = a, *const *sympb = b;
1169 if ((*sympa)->name == NULL && (*sympb)->name == NULL)
1170 return 0;
1171 if ((*sympa)->name == NULL)
1172 return -1;
1173 if ((*sympb)->name == NULL)
1174 return 1;
1175 return strcmp((*sympa)->name, (*sympb)->name);
1176 }
1177
1178 static int compare_symbolp_labels(const void *a, const void *b)
1179 {
1180 const struct ksplice_symbol *const *sympa = a, *const *sympb = b;
1181 return strcmp((*sympa)->label, (*sympb)->label);
1182 }
1183
1184 static int symbolp_bsearch_compare(const void *key, const void *elt)
1185 {
1186 const char *name = key;
1187 const struct ksplice_symbol *const *symp = elt;
1188 const struct ksplice_symbol *sym = *symp;
1189 if (sym->name == NULL)
1190 return 1;
1191 return strcmp(name, sym->name);
1192 }
1193
1194 static abort_t add_matching_values(struct ksplice_lookup *lookup,
1195 const char *sym_name, unsigned long sym_val)
1196 {
1197 struct ksplice_symbol **symp;
1198 abort_t ret;
1199
1200 symp = bsearch(sym_name, lookup->arr, lookup->size,
1201 sizeof(*lookup->arr), symbolp_bsearch_compare);
1202 if (symp == NULL)
1203 return OK;
1204
1205 while (symp > lookup->arr &&
1206 symbolp_bsearch_compare(sym_name, symp - 1) == 0)
1207 symp--;
1208
1209 for (; symp < lookup->arr + lookup->size; symp++) {
1210 struct ksplice_symbol *sym = *symp;
1211 if (sym->name == NULL || strcmp(sym_name, sym->name) != 0)
1212 break;
1213 ret = add_candidate_val(lookup->change,
1214 sym->candidate_vals, sym_val);
1215 if (ret != OK)
1216 return ret;
1217 }
1218 return OK;
1219 }
1220
1221 #ifdef CONFIG_KALLSYMS
1222 static int add_kallsyms_values(void *data, const char *name,
1223 struct module *owner, unsigned long val)
1224 {
1225 struct ksplice_lookup *lookup = data;
1226 if (owner == lookup->change->new_code_mod ||
1227 !patches_module(owner, lookup->change->target))
1228 return (__force int)OK;
1229 return (__force int)add_matching_values(lookup, name, val);
1230 }
1231 #endif /* CONFIG_KALLSYMS */
1232
1233 static bool add_export_values(const struct symsearch *syms,
1234 struct module *owner,
1235 unsigned int symnum, void *data)
1236 {
1237 struct ksplice_lookup *lookup = data;
1238 abort_t ret;
1239
1240 ret = add_matching_values(lookup, syms->start[symnum].name,
1241 syms->start[symnum].value);
1242 if (ret != OK) {
1243 lookup->ret = ret;
1244 return true;
1245 }
1246 return false;
1247 }
1248
1249 static void cleanup_symbol_arrays(struct ksplice_mod_change *change)
1250 {
1251 struct ksplice_symbol *sym;
1252 for (sym = change->new_code.symbols; sym < change->new_code.symbols_end;
1253 sym++) {
1254 if (sym->candidate_vals != NULL) {
1255 clear_list(sym->candidate_vals, struct candidate_val,
1256 list);
1257 kfree(sym->candidate_vals);
1258 sym->candidate_vals = NULL;
1259 }
1260 }
1261 for (sym = change->old_code.symbols; sym < change->old_code.symbols_end;
1262 sym++) {
1263 if (sym->candidate_vals != NULL) {
1264 clear_list(sym->candidate_vals, struct candidate_val,
1265 list);
1266 kfree(sym->candidate_vals);
1267 sym->candidate_vals = NULL;
1268 }
1269 }
1270 }
1271
1272 /*
1273 * The new_code and old_code modules each have their own independent
1274 * ksplice_symbol structures. uniquify_symbols unifies these separate
1275 * pieces of kernel symbol information by replacing all references to
1276 * the old_code copy of symbols with references to the new_code copy.
1277 */
1278 static abort_t uniquify_symbols(struct ksplice_mod_change *change)
1279 {
1280 struct ksplice_reloc *r;
1281 struct ksplice_section *s;
1282 struct ksplice_symbol *sym, **sym_arr, **symp;
1283 size_t size = change->new_code.symbols_end - change->new_code.symbols;
1284
1285 if (size == 0)
1286 return OK;
1287
1288 sym_arr = vmalloc(sizeof(*sym_arr) * size);
1289 if (sym_arr == NULL)
1290 return OUT_OF_MEMORY;
1291
1292 for (symp = sym_arr, sym = change->new_code.symbols;
1293 symp < sym_arr + size && sym < change->new_code.symbols_end;
1294 sym++, symp++)
1295 *symp = sym;
1296
1297 sort(sym_arr, size, sizeof(*sym_arr), compare_symbolp_labels, NULL);
1298
1299 for (r = change->old_code.relocs; r < change->old_code.relocs_end;
1300 r++) {
1301 symp = bsearch(&r->symbol, sym_arr, size, sizeof(*sym_arr),
1302 compare_symbolp_labels);
1303 if (symp != NULL) {
1304 if ((*symp)->name == NULL)
1305 (*symp)->name = r->symbol->name;
1306 r->symbol = *symp;
1307 }
1308 }
1309
1310 for (s = change->old_code.sections; s < change->old_code.sections_end;
1311 s++) {
1312 symp = bsearch(&s->symbol, sym_arr, size, sizeof(*sym_arr),
1313 compare_symbolp_labels);
1314 if (symp != NULL) {
1315 if ((*symp)->name == NULL)
1316 (*symp)->name = s->symbol->name;
1317 s->symbol = *symp;
1318 }
1319 }
1320
1321 vfree(sym_arr);
1322 return OK;
1323 }
1324
1325 /*
1326 * Initialize the ksplice_symbol structures in the given array using
1327 * the kallsyms and exported symbol tables.
1328 */
1329 static abort_t init_symbol_array(struct ksplice_mod_change *change,
1330 struct ksplice_symbol *start,
1331 struct ksplice_symbol *end)
1332 {
1333 struct ksplice_symbol *sym, **sym_arr, **symp;
1334 struct ksplice_lookup lookup;
1335 size_t size = end - start;
1336 abort_t ret;
1337
1338 if (size == 0)
1339 return OK;
1340
1341 for (sym = start; sym < end; sym++) {
1342 if (strstarts(sym->label, "__ksymtab")) {
1343 const struct kernel_symbol *ksym;
1344 const char *colon = strchr(sym->label, ':');
1345 const char *name = colon + 1;
1346 if (colon == NULL)
1347 continue;
1348 ksym = find_symbol(name, NULL, NULL, true, false);
1349 if (ksym == NULL) {
1350 ksdebug(change, "Could not find kernel_symbol "
1351 "structure for %s\n", name);
1352 continue;
1353 }
1354 sym->value = (unsigned long)ksym;
1355 sym->candidate_vals = NULL;
1356 continue;
1357 }
1358
1359 sym->candidate_vals = kmalloc(sizeof(*sym->candidate_vals),
1360 GFP_KERNEL);
1361 if (sym->candidate_vals == NULL)
1362 return OUT_OF_MEMORY;
1363 INIT_LIST_HEAD(sym->candidate_vals);
1364 sym->value = 0;
1365 }
1366
1367 sym_arr = vmalloc(sizeof(*sym_arr) * size);
1368 if (sym_arr == NULL)
1369 return OUT_OF_MEMORY;
1370
1371 for (symp = sym_arr, sym = start; symp < sym_arr + size && sym < end;
1372 sym++, symp++)
1373 *symp = sym;
1374
1375 sort(sym_arr, size, sizeof(*sym_arr), compare_symbolp_names, NULL);
1376
1377 lookup.change = change;
1378 lookup.arr = sym_arr;
1379 lookup.size = size;
1380 lookup.ret = OK;
1381
1382 each_symbol(add_export_values, &lookup);
1383 ret = lookup.ret;
1384 #ifdef CONFIG_KALLSYMS
1385 if (ret == OK)
1386 ret = (__force abort_t)
1387 kallsyms_on_each_symbol(add_kallsyms_values, &lookup);
1388 #endif /* CONFIG_KALLSYMS */
1389 vfree(sym_arr);
1390 return ret;
1391 }
1392
1393 /*
1394 * Prepare the change's ksplice_symbol structures for run-pre matching
1395 *
1396 * noinline to prevent garbage on the stack from confusing check_stack
1397 */
1398 static noinline abort_t init_symbol_arrays(struct ksplice_mod_change *change)
1399 {
1400 abort_t ret;
1401
1402 ret = uniquify_symbols(change);
1403 if (ret != OK)
1404 return ret;
1405
1406 ret = init_symbol_array(change, change->old_code.symbols,
1407 change->old_code.symbols_end);
1408 if (ret != OK)
1409 return ret;
1410
1411 ret = init_symbol_array(change, change->new_code.symbols,
1412 change->new_code.symbols_end);
1413 if (ret != OK)
1414 return ret;
1415
1416 return OK;
1417 }
1418
1419 /* noinline to prevent garbage on the stack from confusing check_stack */
1420 static noinline abort_t prepare_change(struct ksplice_mod_change *change)
1421 {
1422 abort_t ret;
1423
1424 ksdebug(change, "Preparing and checking %s\n", change->name);
1425 ret = match_change_sections(change, false);
1426 if (ret == NO_MATCH) {
1427 /* It is possible that by using relocations from .data sections
1428 * we can successfully run-pre match the rest of the sections.
1429 * To avoid using any symbols obtained from .data sections
1430 * (which may be unreliable) in the post code, we first prepare
1431 * the post code and then try to run-pre match the remaining
1432 * sections with the help of .data sections.
1433 */
1434 ksdebug(change, "Continuing without some sections; we might "
1435 "find them later.\n");
1436 ret = finalize_change(change);
1437 if (ret != OK) {
1438 ksdebug(change, "Aborted. Unable to continue without "
1439 "the unmatched sections.\n");
1440 return ret;
1441 }
1442
1443 ksdebug(change, "run-pre: Considering .data sections to find "
1444 "the unmatched sections\n");
1445 ret = match_change_sections(change, true);
1446 if (ret != OK)
1447 return ret;
1448
1449 ksdebug(change, "run-pre: Found all previously unmatched "
1450 "sections\n");
1451 return OK;
1452 } else if (ret != OK) {
1453 return ret;
1454 }
1455
1456 return finalize_change(change);
1457 }
1458
1459 /*
1460 * Finish preparing the change for insertion into the kernel.
1461 * Afterwards, the replacement code should be ready to run and the
1462 * ksplice_patches should all be ready for trampoline insertion.
1463 */
1464 static abort_t finalize_change(struct ksplice_mod_change *change)
1465 {
1466 abort_t ret;
1467 ret = apply_relocs(change, change->new_code.relocs,
1468 change->new_code.relocs_end);
1469 if (ret != OK)
1470 return ret;
1471
1472 ret = finalize_patches(change);
1473 if (ret != OK)
1474 return ret;
1475
1476 return OK;
1477 }
1478
1479 static abort_t finalize_patches(struct ksplice_mod_change *change)
1480 {
1481 struct ksplice_patch *p;
1482 struct safety_record *rec;
1483 abort_t ret;
1484
1485 for (p = change->patches; p < change->patches_end; p++) {
1486 bool found = false;
1487 list_for_each_entry(rec, &change->safety_records, list) {
1488 if (rec->addr <= p->oldaddr &&
1489 p->oldaddr < rec->addr + rec->size) {
1490 found = true;
1491 break;
1492 }
1493 }
1494 if (!found && p->type != KSPLICE_PATCH_EXPORT) {
1495 const struct ksplice_reloc *r = patch_reloc(change, p);
1496 if (r == NULL) {
1497 ksdebug(change, "A patch with no reloc at its "
1498 "oldaddr has no safety record\n");
1499 return NO_MATCH;
1500 }
1501 ksdebug(change, "No safety record for patch with "
1502 "oldaddr %s+%lx\n", r->symbol->label,
1503 r->target_addend);
1504 return NO_MATCH;
1505 }
1506
1507 if (p->type == KSPLICE_PATCH_TEXT) {
1508 ret = prepare_trampoline(change, p);
1509 if (ret != OK)
1510 return ret;
1511 }
1512
1513 if (found && rec->addr + rec->size < p->oldaddr + p->size) {
1514 ksdebug(change, "Safety record %s is too short for "
1515 "patch\n", rec->label);
1516 return UNEXPECTED;
1517 }
1518
1519 if (p->type == KSPLICE_PATCH_TEXT) {
1520 if (p->repladdr == 0)
1521 p->repladdr = (unsigned long)ksplice_deleted;
1522 }
1523 }
1524
1525 for (p = change->patches; p < change->patches_end; p++) {
1526 struct ksplice_patch *q;
1527 for (q = change->patches; q < change->patches_end; q++) {
1528 if (p != q && p->oldaddr <= q->oldaddr &&
1529 p->oldaddr + p->size > q->oldaddr) {
1530 ksdebug(change, "Overlapping oldaddrs "
1531 "for patches\n");
1532 return UNEXPECTED;
1533 }
1534 }
1535 }
1536
1537 return OK;
1538 }
1539
1540 /* noinline to prevent garbage on the stack from confusing check_stack */
1541 static noinline abort_t map_trampoline_pages(struct update *update)
1542 {
1543 struct ksplice_mod_change *change;
1544 list_for_each_entry(change, &update->changes, list) {
1545 struct ksplice_patch *p;
1546 for (p = change->patches; p < change->patches_end; p++) {
1547 p->vaddr = map_writable((void *)p->oldaddr, p->size);
1548 if (p->vaddr == NULL) {
1549 ksdebug(change,
1550 "Unable to map oldaddr read/write\n");
1551 unmap_trampoline_pages(update);
1552 return UNEXPECTED;
1553 }
1554 }
1555 }
1556 return OK;
1557 }
1558
1559 static void unmap_trampoline_pages(struct update *update)
1560 {
1561 struct ksplice_mod_change *change;
1562 list_for_each_entry(change, &update->changes, list) {
1563 struct ksplice_patch *p;
1564 for (p = change->patches; p < change->patches_end; p++) {
1565 vunmap((void *)((unsigned long)p->vaddr & PAGE_MASK));
1566 p->vaddr = NULL;
1567 }
1568 }
1569 }
1570
1571 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22) && defined(CONFIG_X86_64)
1572 /* e3ebadd95cb621e2c7436f3d3646447ac9d5c16d was after 2.6.21 */
1573 #define phys_base ({EXTRACT_SYMBOL(phys_base); phys_base;})
1574 #endif /* LINUX_VERSION_CODE && CONFIG_X86_64 */
1575
1576 /*
1577 * map_writable creates a shadow page mapping of the range
1578 * [addr, addr + len) so that we can write to code mapped read-only.
1579 *
1580 * It is similar to a generalized version of x86's text_poke. But
1581 * because one cannot use vmalloc/vfree() inside stop_machine, we use
1582 * map_writable to map the pages before stop_machine, then use the
1583 * mapping inside stop_machine, and unmap the pages afterwards.
1584 */
1585 static void *map_writable(void *addr, size_t len)
1586 {
1587 void *vaddr;
1588 int nr_pages = DIV_ROUND_UP(offset_in_page(addr) + len, PAGE_SIZE);
1589 struct page **pages = kmalloc(nr_pages * sizeof(*pages), GFP_KERNEL);
1590 void *page_addr = (void *)((unsigned long)addr & PAGE_MASK);
1591 int i;
1592
1593 if (pages == NULL)
1594 return NULL;
1595
1596 for (i = 0; i < nr_pages; i++) {
1597 if (__module_address((unsigned long)page_addr) == NULL) {
1598 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22) || !defined(CONFIG_X86_64)
1599 pages[i] = virt_to_page(page_addr);
1600 #else /* LINUX_VERSION_CODE < && CONFIG_X86_64 */
1601 /* e3ebadd95cb621e2c7436f3d3646447ac9d5c16d was after 2.6.21
1602 * This works around a broken virt_to_page() from the RHEL 5 backport
1603 * of x86-64 relocatable kernel support.
1604 */
1605 pages[i] =
1606 pfn_to_page(__pa_symbol(page_addr) >> PAGE_SHIFT);
1607 #endif /* LINUX_VERSION_CODE || !CONFIG_X86_64 */
1608 WARN_ON(!PageReserved(pages[i]));
1609 } else {
1610 pages[i] = vmalloc_to_page(addr);
1611 }
1612 if (pages[i] == NULL) {
1613 kfree(pages);
1614 return NULL;
1615 }
1616 page_addr += PAGE_SIZE;
1617 }
1618 vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
1619 kfree(pages);
1620 if (vaddr == NULL)
1621 return NULL;
1622 return vaddr + offset_in_page(addr);
1623 }
1624
1625 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
1626 /* c6b37801911d7f4663c99cad8aa230bc934cea82 was after 2.6.29 */
1627 EXTRACT_SYMBOL(__module_text_address);
1628 #endif /* LINUX_VERSION_CODE */
1629
1630 /*
1631 * Ksplice adds a dependency on any symbol address used to resolve
1632 * relocations in the new_code module.
1633 *
1634 * Be careful to follow_trampolines so that we always depend on the
1635 * latest version of the target function, since that's the code that
1636 * will run if we call addr.
1637 */
1638 static abort_t add_dependency_on_address(struct ksplice_mod_change *change,
1639 unsigned long addr)
1640 {
1641 struct ksplice_mod_change *c;
1642 struct module *m =
1643 __module_text_address(follow_trampolines(change, addr));
1644 if (m == NULL)
1645 return OK;
1646 list_for_each_entry(c, &change->update->changes, list) {
1647 if (m == c->new_code_mod)
1648 return OK;
1649 }
1650 if (use_module(change->new_code_mod, m) != 1)
1651 return MODULE_BUSY;
1652 return OK;
1653 }
1654
1655 static abort_t apply_relocs(struct ksplice_mod_change *change,
1656 const struct ksplice_reloc *relocs,
1657 const struct ksplice_reloc *relocs_end)
1658 {
1659 const struct ksplice_reloc *r;
1660 for (r = relocs; r < relocs_end; r++) {
1661 abort_t ret = apply_reloc(change, r);
1662 if (ret != OK)
1663 return ret;
1664 }
1665 return OK;
1666 }
1667
1668 static abort_t apply_reloc(struct ksplice_mod_change *change,
1669 const struct ksplice_reloc *r)
1670 {
1671 switch (r->howto->type) {
1672 case KSPLICE_HOWTO_RELOC:
1673 case KSPLICE_HOWTO_RELOC_PATCH:
1674 return apply_howto_reloc(change, r);
1675 case KSPLICE_HOWTO_DATE:
1676 case KSPLICE_HOWTO_TIME:
1677 return apply_howto_date(change, r);
1678 default:
1679 ksdebug(change, "Unexpected howto type %d\n", r->howto->type);
1680 return UNEXPECTED;
1681 }
1682 }
1683
1684 /*
1685 * Applies a relocation. Aborts if the symbol referenced in it has
1686 * not been uniquely resolved.
1687 */
1688 static abort_t apply_howto_reloc(struct ksplice_mod_change *change,
1689 const struct ksplice_reloc *r)
1690 {
1691 abort_t ret;
1692 int canary_ret;
1693 unsigned long sym_addr;
1694 LIST_HEAD(vals);
1695
1696 canary_ret = contains_canary(change, r->blank_addr, r->howto);
1697 if (canary_ret < 0)
1698 return UNEXPECTED;
1699 if (canary_ret == 0) {
1700 ksdebug(change, "reloc: skipped %lx to %s+%lx (altinstr)\n",
1701 r->blank_addr, r->symbol->label, r->target_addend);
1702 return OK;
1703 }
1704
1705 #ifdef KSPLICE_STANDALONE
1706 if (!bootstrapped) {
1707 ret = add_system_map_candidates(change,
1708 change->new_code.system_map,
1709 change->new_code.system_map_end,
1710 r->symbol->label, &vals);
1711 if (ret != OK) {
1712 release_vals(&vals);
1713 return ret;
1714 }
1715 }
1716 #endif /* KSPLICE_STANDALONE */
1717 ret = lookup_symbol(change, r->symbol, &vals);
1718 if (ret != OK) {
1719 release_vals(&vals);
1720 return ret;
1721 }
1722 /*
1723 * Relocations for the oldaddr fields of patches must have
1724 * been resolved via run-pre matching.
1725 */
1726 if (!singular(&vals) || (r->symbol->candidate_vals != NULL &&
1727 r->howto->type == KSPLICE_HOWTO_RELOC_PATCH)) {
1728 release_vals(&vals);
1729 ksdebug(change, "Failed to find %s for reloc\n",
1730 r->symbol->label);
1731 return FAILED_TO_FIND;
1732 }
1733 sym_addr = list_entry(vals.next, struct candidate_val, list)->val;
1734 release_vals(&vals);
1735
1736 ret = write_reloc_value(change, r, r->blank_addr,
1737 r->howto->pcrel ? sym_addr - r->blank_addr :
1738 sym_addr);
1739 if (ret != OK)
1740 return ret;
1741
1742 ksdebug(change, "reloc: %lx to %s+%lx (S=%lx ", r->blank_addr,
1743 r->symbol->label, r->target_addend, sym_addr);
1744 switch (r->howto->size) {
1745 case 1:
1746 ksdebug(change, "aft=%02x)\n", *(uint8_t *)r->blank_addr);
1747 break;
1748 case 2:
1749 ksdebug(change, "aft=%04x)\n", *(uint16_t *)r->blank_addr);
1750 break;
1751 case 4:
1752 ksdebug(change, "aft=%08x)\n", *(uint32_t *)r->blank_addr);
1753 break;
1754 #if BITS_PER_LONG >= 64
1755 case 8:
1756 ksdebug(change, "aft=%016llx)\n", *(uint64_t *)r->blank_addr);
1757 break;
1758 #endif /* BITS_PER_LONG */
1759 default:
1760 ksdebug(change, "Aborted. Invalid relocation size.\n");
1761 return UNEXPECTED;
1762 }
1763 #ifdef KSPLICE_STANDALONE
1764 if (!bootstrapped)
1765 return OK;
1766 #endif /* KSPLICE_STANDALONE */
1767
1768 /*
1769 * Create labelvals so that we can verify our choices in the
1770 * second round of run-pre matching that considers data sections.
1771 */
1772 ret = create_labelval(change, r->symbol, sym_addr, VAL);
1773 if (ret != OK)
1774 return ret;
1775
1776 return add_dependency_on_address(change, sym_addr);
1777 }
1778
1779 /*
1780 * Date relocations are created wherever __DATE__ or __TIME__ is used
1781 * in the kernel; we resolve them by simply copying in the date/time
1782 * obtained from run-pre matching the relevant compilation unit.
1783 */
1784 static abort_t apply_howto_date(struct ksplice_mod_change *change,
1785 const struct ksplice_reloc *r)
1786 {
1787 if (r->symbol->candidate_vals != NULL) {
1788 ksdebug(change, "Failed to find %s for date\n",
1789 r->symbol->label);
1790 return FAILED_TO_FIND;
1791 }
1792 memcpy((unsigned char *)r->blank_addr,
1793 (const unsigned char *)r->symbol->value, r->howto->size);
1794 return OK;
1795 }
1796
1797 /*
1798 * Given a relocation and its run address, compute the address of the
1799 * symbol the relocation referenced, and store it in *valp.
1800 */
1801 static abort_t read_reloc_value(struct ksplice_mod_change *change,
1802 const struct ksplice_reloc *r,
1803 unsigned long addr, unsigned long *valp)
1804 {
1805 unsigned char bytes[sizeof(long)];
1806 unsigned long val;
1807 const struct ksplice_reloc_howto *howto = r->howto;
1808
1809 if (howto->size <= 0 || howto->size > sizeof(long)) {
1810 ksdebug(change, "Aborted. Invalid relocation size.\n");
1811 return UNEXPECTED;
1812 }
1813
1814 if (probe_kernel_read(bytes, (void *)addr, howto->size) == -EFAULT)
1815 return NO_MATCH;
1816
1817 switch (howto->size) {
1818 case 1:
1819 val = *(uint8_t *)bytes;
1820 break;
1821 case 2:
1822 val = *(uint16_t *)bytes;
1823 break;
1824 case 4:
1825 val = *(uint32_t *)bytes;
1826 break;
1827 #if BITS_PER_LONG >= 64
1828 case 8:
1829 val = *(uint64_t *)bytes;
1830 break;
1831 #endif /* BITS_PER_LONG */
1832 default:
1833 ksdebug(change, "Aborted. Invalid relocation size.\n");
1834 return UNEXPECTED;
1835 }
1836
1837 val &= howto->dst_mask;
1838 if (howto->signed_addend)
1839 val |= -(val & (howto->dst_mask & ~(howto->dst_mask >> 1)));
1840 val <<= howto->rightshift;
1841 val -= r->insn_addend + r->target_addend;
1842 *valp = val;
1843 return OK;
1844 }
1845
1846 /*
1847 * Given a relocation, the address of its storage unit, and the
1848 * address of the symbol the relocation references, write the
1849 * relocation's final value into the storage unit.
1850 */
1851 static abort_t write_reloc_value(struct ksplice_mod_change *change,
1852 const struct ksplice_reloc *r,
1853 unsigned long addr, unsigned long sym_addr)
1854 {
1855 unsigned long val = sym_addr + r->target_addend + r->insn_addend;
1856 const struct ksplice_reloc_howto *howto = r->howto;
1857 val >>= howto->rightshift;
1858 switch (howto->size) {
1859 case 1:
1860 *(uint8_t *)addr = (*(uint8_t *)addr & ~howto->dst_mask) |
1861 (val & howto->dst_mask);
1862 break;
1863 case 2:
1864 *(uint16_t *)addr = (*(uint16_t *)addr & ~howto->dst_mask) |
1865 (val & howto->dst_mask);
1866 break;
1867 case 4:
1868 *(uint32_t *)addr = (*(uint32_t *)addr & ~howto->dst_mask) |
1869 (val & howto->dst_mask);
1870 break;
1871 #if BITS_PER_LONG >= 64
1872 case 8:
1873 *(uint64_t *)addr = (*(uint64_t *)addr & ~howto->dst_mask) |
1874 (val & howto->dst_mask);
1875 break;
1876 #endif /* BITS_PER_LONG */
1877 default:
1878 ksdebug(change, "Aborted. Invalid relocation size.\n");
1879 return UNEXPECTED;
1880 }
1881
1882 if (read_reloc_value(change, r, addr, &val) != OK || val != sym_addr) {
1883 ksdebug(change, "Aborted. Relocation overflow.\n");
1884 return UNEXPECTED;
1885 }
1886
1887 return OK;
1888 }
1889
1890 static abort_t create_module_list_entry(struct ksplice_mod_change *change,
1891 bool to_be_applied)
1892 {
1893 struct ksplice_module_list_entry *entry =
1894 kmalloc(sizeof(*entry), GFP_KERNEL);
1895 if (entry == NULL)
1896 return OUT_OF_MEMORY;
1897 entry->new_code_mod_name =
1898 kstrdup(change->new_code_mod->name, GFP_KERNEL);
1899 if (entry->new_code_mod_name == NULL) {
1900 kfree(entry);
1901 return OUT_OF_MEMORY;
1902 }
1903 entry->target_mod_name = kstrdup(change->target_name, GFP_KERNEL);
1904 if (entry->target_mod_name == NULL) {
1905 kfree(entry->new_code_mod_name);
1906 kfree(entry);
1907 return OUT_OF_MEMORY;
1908 }
1909 /* The update's kid is guaranteed to outlast the module_list_entry */
1910 entry->kid = change->update->kid;
1911 entry->applied = to_be_applied;
1912 list_add(&entry->update_list, &change->update->ksplice_module_list);
1913 return OK;
1914 }
1915
1916 static void cleanup_module_list_entries(struct update *update)
1917 {
1918 struct ksplice_module_list_entry *entry;
1919 list_for_each_entry(entry, &update->ksplice_module_list, update_list) {
1920 kfree(entry->target_mod_name);
1921 kfree(entry->new_code_mod_name);
1922 }
1923 clear_list(&update->ksplice_module_list,
1924 struct ksplice_module_list_entry, update_list);
1925 }
1926
1927 /* Replacement address used for functions deleted by the patch */
1928 static void __attribute__((noreturn)) ksplice_deleted(void)
1929 {
1930 printk(KERN_CRIT "Called a kernel function deleted by Ksplice!\n");
1931 BUG();
1932 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
1933 /* 91768d6c2bad0d2766a166f13f2f57e197de3458 was after 2.6.19 */
1934 for (;;);
1935 #endif
1936 }
1937
1938 /* Floodfill to run-pre match the sections within a change. */
1939 static abort_t match_change_sections(struct ksplice_mod_change *change,
1940 bool consider_data_sections)
1941 {
1942 struct ksplice_section *sect;
1943 abort_t ret;
1944 int remaining = 0;
1945 bool progress;
1946
1947 for (sect = change->old_code.sections;
1948 sect < change->old_code.sections_end; sect++) {
1949 if ((sect->flags & KSPLICE_SECTION_DATA) == 0 &&
1950 (sect->flags & KSPLICE_SECTION_STRING) == 0 &&
1951 (sect->flags & KSPLICE_SECTION_MATCHED) == 0)
1952 remaining++;
1953 }
1954
1955 while (remaining > 0) {
1956 progress = false;
1957 for (sect = change->old_code.sections;
1958 sect < change->old_code.sections_end; sect++) {
1959 if ((sect->flags & KSPLICE_SECTION_MATCHED) != 0)
1960 continue;
1961 if ((!consider_data_sections &&
1962 (sect->flags & KSPLICE_SECTION_DATA) != 0) ||
1963 (sect->flags & KSPLICE_SECTION_STRING) != 0)
1964 continue;
1965 ret = find_section(change, sect);
1966 if (ret == OK) {
1967 sect->flags |= KSPLICE_SECTION_MATCHED;
1968 if ((sect->flags & KSPLICE_SECTION_DATA) == 0)
1969 remaining--;
1970 progress = true;
1971 } else if (ret != NO_MATCH) {
1972 return ret;
1973 }
1974 }
1975
1976 if (progress)
1977 continue;
1978
1979 for (sect = change->old_code.sections;
1980 sect < change->old_code.sections_end; sect++) {
1981 if ((sect->flags & KSPLICE_SECTION_MATCHED) != 0 ||
1982 (sect->flags & KSPLICE_SECTION_STRING) != 0)
1983 continue;
1984 ksdebug(change, "run-pre: could not match %s "
1985 "section %s\n",
1986 (sect->flags & KSPLICE_SECTION_DATA) != 0 ?
1987 "data" :
1988 (sect->flags & KSPLICE_SECTION_RODATA) != 0 ?
1989 "rodata" : "text", sect->symbol->label);
1990 }
1991 ksdebug(change, "Aborted. run-pre: could not match some "
1992 "sections.\n");
1993 return NO_MATCH;
1994 }
1995 return OK;
1996 }
1997
1998 /*
1999 * Search for the section in the running kernel. Returns OK if and
2000 * only if it finds precisely one address in the kernel matching the
2001 * section.
2002 */
2003 static abort_t find_section(struct ksplice_mod_change *change,
2004 struct ksplice_section *sect)
2005 {
2006 int i;
2007 abort_t ret;
2008 unsigned long run_addr;
2009 LIST_HEAD(vals);
2010 struct candidate_val *v, *n;
2011
2012 #ifdef KSPLICE_STANDALONE
2013 ret = add_system_map_candidates(change, change->old_code.system_map,
2014 change->old_code.system_map_end,
2015 sect->symbol->label, &vals);
2016 if (ret != OK) {
2017 release_vals(&vals);
2018 return ret;
2019 }
2020 #endif /* KSPLICE_STANDALONE */
2021 ret = lookup_symbol(change, sect->symbol, &vals);
2022 if (ret != OK) {
2023 release_vals(&vals);
2024 return ret;
2025 }
2026
2027 ksdebug(change, "run-pre: starting sect search for %s\n",
2028 sect->symbol->label);
2029
2030 list_for_each_entry_safe(v, n, &vals, list) {
2031 run_addr = v->val;
2032
2033 yield();
2034 ret = try_addr(change, sect, run_addr, NULL, RUN_PRE_INITIAL);
2035 if (ret == NO_MATCH) {
2036 list_del(&v->list);
2037 kfree(v);
2038 } else if (ret != OK) {
2039 release_vals(&vals);
2040 return ret;
2041 }
2042 }
2043
2044 #if defined(KSPLICE_STANDALONE) && !defined(CONFIG_KALLSYMS)
2045 if (list_empty(&vals) && (sect->flags & KSPLICE_SECTION_DATA) == 0) {
2046 ret = brute_search_all(change, sect, &vals);
2047 if (ret != OK) {
2048 release_vals(&vals);
2049 return ret;
2050 }
2051 /*
2052 * Make sure run-pre matching output is displayed if
2053 * brute_search succeeds.
2054 */
2055 if (singular(&vals)) {
2056 run_addr = list_entry(vals.next, struct candidate_val,
2057 list)->val;
2058 ret = try_addr(change, sect, run_addr, NULL,
2059 RUN_PRE_INITIAL);
2060 if (ret != OK) {
2061 ksdebug(change, "run-pre: Debug run failed for "
2062 "sect %s:\n", sect->symbol->label);
2063 release_vals(&vals);
2064 return ret;
2065 }
2066 }
2067 }
2068 #endif /* KSPLICE_STANDALONE && !CONFIG_KALLSYMS */
2069
2070 if (singular(&vals)) {
2071 LIST_HEAD(safety_records);
2072 run_addr = list_entry(vals.next, struct candidate_val,
2073 list)->val;
2074 ret = try_addr(change, sect, run_addr, &safety_records,
2075 RUN_PRE_FINAL);
2076 release_vals(&vals);
2077 if (ret != OK) {
2078 clear_list(&safety_records, struct safety_record, list);
2079 ksdebug(change, "run-pre: Final run failed for sect "
2080 "%s:\n", sect->symbol->label);
2081 } else {
2082 list_splice(&safety_records, &change->safety_records);
2083 }
2084 return ret;
2085 } else if (!list_empty(&vals)) {
2086 struct candidate_val *val;
2087 ksdebug(change, "run-pre: multiple candidates for sect %s:\n",
2088 sect->symbol->label);
2089 i = 0;
2090 list_for_each_entry(val, &vals, list) {
2091 i++;
2092 ksdebug(change, "%lx\n", val->val);
2093 if (i > 5) {
2094 ksdebug(change, "...\n");
2095 break;
2096 }
2097 }
2098 release_vals(&vals);
2099 return NO_MATCH;
2100 }
2101 release_vals(&vals);
2102 return NO_MATCH;
2103 }
2104
2105 /*
2106 * try_addr is the the interface to run-pre matching. Its primary
2107 * purpose is to manage debugging information for run-pre matching;
2108 * all the hard work is in run_pre_cmp.
2109 */
2110 static abort_t try_addr(struct ksplice_mod_change *change,
2111 struct ksplice_section *sect,
2112 unsigned long run_addr,
2113 struct list_head *safety_records,
2114 enum run_pre_mode mode)
2115 {
2116 abort_t ret;
2117 const struct module *run_module = __module_address(run_addr);
2118
2119 if (run_module == change->new_code_mod) {
2120 ksdebug(change, "run-pre: unexpected address %lx in new_code "
2121 "module %s for sect %s\n", run_addr, run_module->name,
2122 sect->symbol->label);
2123 return UNEXPECTED;
2124 }
2125 if (!patches_module(run_module, change->target)) {
2126 ksdebug(change, "run-pre: ignoring address %lx in other module "
2127 "%s for sect %s\n", run_addr, run_module == NULL ?
2128 "vmlinux" : run_module->name, sect->symbol->label);
2129 return NO_MATCH;
2130 }
2131
2132 ret = create_labelval(change, sect->symbol, run_addr, TEMP);
2133 if (ret != OK)
2134 return ret;
2135
2136 #ifdef CONFIG_FUNCTION_DATA_SECTIONS
2137 ret = run_pre_cmp(change, sect, run_addr, safety_records, mode);
2138 #else /* !CONFIG_FUNCTION_DATA_SECTIONS */
2139 if ((sect->flags & KSPLICE_SECTION_TEXT) != 0)
2140 ret = arch_run_pre_cmp(change, sect, run_addr, safety_records,
2141 mode);
2142 else
2143 ret = run_pre_cmp(change, sect, run_addr, safety_records, mode);
2144 #endif /* CONFIG_FUNCTION_DATA_SECTIONS */
2145 if (ret == NO_MATCH && mode != RUN_PRE_FINAL) {
2146 set_temp_labelvals(change, NOVAL);
2147 ksdebug(change, "run-pre: %s sect %s does not match (r_a=%lx "
2148 "p_a=%lx s=%lx)\n",
2149 (sect->flags & KSPLICE_SECTION_RODATA) != 0 ? "rodata" :
2150 (sect->flags & KSPLICE_SECTION_DATA) != 0 ? "data" :
2151 "text", sect->symbol->label, run_addr, sect->address,
2152 sect->size);
2153 ksdebug(change, "run-pre: ");
2154 if (change->update->debug >= 1) {
2155 #ifdef CONFIG_FUNCTION_DATA_SECTIONS
2156 ret = run_pre_cmp(change, sect, run_addr,
2157 safety_records, RUN_PRE_DEBUG);
2158 #else /* !CONFIG_FUNCTION_DATA_SECTIONS */
2159 if ((sect->flags & KSPLICE_SECTION_TEXT) != 0)
2160 ret = arch_run_pre_cmp(change, sect, run_addr,
2161 safety_records,
2162 RUN_PRE_DEBUG);
2163 else
2164 ret = run_pre_cmp(change, sect, run_addr,
2165 safety_records,
2166 RUN_PRE_DEBUG);
2167 #endif /* CONFIG_FUNCTION_DATA_SECTIONS */
2168 set_temp_labelvals(change, NOVAL);
2169 }
2170 ksdebug(change, "\n");
2171 return ret;
2172 } else if (ret != OK) {
2173 set_temp_labelvals(change, NOVAL);
2174 return ret;
2175 }
2176
2177 if (mode != RUN_PRE_FINAL) {
2178 set_temp_labelvals(change, NOVAL);
2179 ksdebug(change, "run-pre: candidate for sect %s=%lx\n",
2180 sect->symbol->label, run_addr);
2181 return OK;
2182 }
2183
2184 set_temp_labelvals(change, VAL);
2185 ksdebug(change, "run-pre: found sect %s=%lx\n", sect->symbol->label,
2186 run_addr);
2187 return OK;
2188 }
2189
2190 /*
2191 * run_pre_cmp is the primary run-pre matching function; it determines
2192 * whether the given ksplice_section matches the code or data in the
2193 * running kernel starting at run_addr.
2194 *
2195 * If run_pre_mode is RUN_PRE_FINAL, a safety record for the matched
2196 * section is created.
2197 *
2198 * The run_pre_mode is also used to determine what debugging
2199 * information to display.
2200 */
2201 static abort_t run_pre_cmp(struct ksplice_mod_change *change,
2202 const struct ksplice_section *sect,
2203 unsigned long run_addr,
2204 struct list_head *safety_records,
2205 enum run_pre_mode mode)
2206 {
2207 int matched = 0;
2208 abort_t ret;
2209 const struct ksplice_reloc *r, *finger;
2210 const unsigned char *pre, *run, *pre_start, *run_start;
2211 unsigned char runval;
2212
2213 pre_start = (const unsigned char *)sect->address;
2214 run_start = (const unsigned char *)run_addr;
2215
2216 finger = init_reloc_search(change, sect);
2217
2218 pre = pre_start;
2219 run = run_start;
2220 while (pre < pre_start + sect->size) {
2221 unsigned long offset = pre - pre_start;
2222 ret = lookup_reloc(change, &finger, (unsigned long)pre, &r);
2223 if (ret == OK) {
2224 ret = handle_reloc(change, sect, r, (unsigned long)run,
2225 mode);
2226 if (ret != OK) {
2227 if (mode == RUN_PRE_INITIAL)
2228 ksdebug(change, "reloc in sect does "
2229 "not match after %lx/%lx "
2230 "bytes\n", offset, sect->size);
2231 return ret;
2232 }
2233 if (mode == RUN_PRE_DEBUG)
2234 print_bytes(change, run, r->howto->size, pre,
2235 r->howto->size);
2236 pre += r->howto->size;
2237 run += r->howto->size;
2238 finger++;
2239 continue;
2240 } else if (ret != NO_MATCH) {
2241 return ret;
2242 }
2243
2244 if ((sect->flags & KSPLICE_SECTION_TEXT) != 0) {
2245 ret = handle_paravirt(change, (unsigned long)pre,
2246 (unsigned long)run, &matched);
2247 if (ret != OK)
2248 return ret;
2249 if (matched != 0) {
2250 if (mode == RUN_PRE_DEBUG)
2251 print_bytes(change, run, matched, pre,
2252 matched);
2253 pre += matched;
2254 run += matched;
2255 continue;
2256 }
2257 }
2258
2259 if (probe_kernel_read(&runval, (void *)run, 1) == -EFAULT) {
2260 if (mode == RUN_PRE_INITIAL)
2261 ksdebug(change, "sect unmapped after %lx/%lx "
2262 "bytes\n", offset, sect->size);
2263 return NO_MATCH;
2264 }
2265
2266 if (runval != *pre &&
2267 (sect->flags & KSPLICE_SECTION_DATA) == 0) {
2268 if (mode == RUN_PRE_INITIAL)
2269 ksdebug(change, "sect does not match after "
2270 "%lx/%lx bytes\n", offset, sect->size);
2271 if (mode == RUN_PRE_DEBUG) {
2272 print_bytes(change, run, 1, pre, 1);
2273 ksdebug(change, "[p_o=%lx] ! ", offset);
2274 print_bytes(change, run + 1, 2, pre + 1, 2);
2275 }
2276 return NO_MATCH;
2277 }
2278 if (mode == RUN_PRE_DEBUG)
2279 print_bytes(change, run, 1, pre, 1);
2280 pre++;
2281 run++;
2282 }
2283 return create_safety_record(change, sect, safety_records, run_addr,
2284 run - run_start);
2285 }
2286
2287 static void print_bytes(struct ksplice_mod_change *change,
2288 const unsigned char *run, int runc,
2289 const unsigned char *pre, int prec)
2290 {
2291 int o;
2292 int matched = min(runc, prec);
2293 for (o = 0; o < matched; o++) {
2294 if (run[o] == pre[o])
2295 ksdebug(change, "%02x ", run[o]);
2296 else
2297 ksdebug(change, "%02x/%02x ", run[o], pre[o]);
2298 }
2299 for (o = matched; o < runc; o++)
2300 ksdebug(change, "%02x/ ", run[o]);
2301 for (o = matched; o < prec; o++)
2302 ksdebug(change, "/%02x ", pre[o]);
2303 }
2304
2305 #if defined(KSPLICE_STANDALONE) && !defined(CONFIG_KALLSYMS)
2306 static abort_t brute_search(struct ksplice_mod_change *change,
2307 struct ksplice_section *sect,
2308 const void *start, unsigned long len,
2309 struct list_head *vals)
2310 {
2311 unsigned long addr;
2312 char run, pre;
2313 abort_t ret;
2314
2315 for (addr = (unsigned long)start; addr < (unsigned long)start + len;
2316 addr++) {
2317 if (addr % 100000 == 0)
2318 yield();
2319
2320 if (probe_kernel_read(&run, (void *)addr, 1) == -EFAULT)
2321 return OK;
2322
2323 pre = *(const unsigned char *)(sect->address);
2324
2325 if (run != pre)
2326 continue;
2327
2328 ret = try_addr(change, sect, addr, NULL, RUN_PRE_INITIAL);
2329 if (ret == OK) {
2330 ret = add_candidate_val(change, vals, addr);
2331 if (ret != OK)
2332 return ret;
2333 } else if (ret != NO_MATCH) {
2334 return ret;
2335 }
2336 }
2337
2338 return OK;
2339 }
2340
2341 extern struct list_head modules;
2342 EXTRACT_SYMBOL(modules);
2343 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
2344 /* 3abf024d2abb79614d8c4cb25a70d5596f77d0ad was after 2.6.24 */
2345 EXTRACT_SYMBOL(init_mm);
2346 #endif /* LINUX_VERSION_CODE */
2347
2348 static abort_t brute_search_all(struct ksplice_mod_change *change,
2349 struct ksplice_section *sect,
2350 struct list_head *vals)
2351 {
2352 struct module *m;
2353 abort_t ret = OK;
2354 int saved_debug;
2355
2356 ksdebug(change, "brute_search: searching for %s\n",
2357 sect->symbol->label);
2358 saved_debug = change->update->debug;
2359 change->update->debug = 0;
2360
2361 list_for_each_entry(m, &modules, list) {
2362 if (!patches_module(m, change->target) ||
2363 m == change->new_code_mod)
2364 continue;
2365 ret = brute_search(change, sect, m->module_core, m->core_size,
2366 vals);
2367 if (ret != OK)
2368 goto out;
2369 ret = brute_search(change, sect, m->module_init, m->init_size,
2370 vals);
2371 if (ret != OK)
2372 goto out;
2373 }
2374
2375 ret = brute_search(change, sect, (const void *)init_mm.start_code,
2376 init_mm.end_code - init_mm.start_code, vals);
2377
2378 out:
2379 change->update->debug = saved_debug;
2380 return ret;
2381 }
2382 #endif /* KSPLICE_STANDALONE && !CONFIG_KALLSYMS */
2383
2384 struct range {
2385 unsigned long address;
2386 unsigned long size;
2387 };
2388
2389 static int reloc_bsearch_compare(const void *key, const void *elt)
2390 {
2391 const struct range *range = key;
2392 const struct ksplice_reloc *r = elt;
2393 if (range->address + range->size <= r->blank_addr)
2394 return -1;
2395 if (range->address > r->blank_addr)
2396 return 1;
2397 return 0;
2398 }
2399
2400 static const struct ksplice_reloc *find_reloc(const struct ksplice_reloc *start,
2401 const struct ksplice_reloc *end,
2402 unsigned long address,
2403 unsigned long size)
2404 {
2405 const struct ksplice_reloc *r;
2406 struct range range = { address, size };
2407 r = bsearch((void *)&range, start, end - start, sizeof(*r),
2408 reloc_bsearch_compare);
2409 if (r == NULL)
2410 return NULL;
2411 while (r > start && (r - 1)->blank_addr >= address)
2412 r--;
2413 return r;
2414 }
2415
2416 static const struct ksplice_reloc *
2417 init_reloc_search(struct ksplice_mod_change *change,
2418 const struct ksplice_section *sect)
2419 {
2420 const struct ksplice_reloc *r;
2421 r = find_reloc(change->old_code.relocs, change->old_code.relocs_end,
2422 sect->address, sect->size);
2423 if (r == NULL)
2424 return change->old_code.relocs_end;
2425 return r;
2426 }
2427
2428 /*
2429 * lookup_reloc implements an amortized O(1) lookup for the next
2430 * old_code relocation. It must be called with a strictly increasing
2431 * sequence of addresses.
2432 *
2433 * The fingerp is private data for lookup_reloc, and needs to have
2434 * been initialized as a pointer to the result of find_reloc (or
2435 * init_reloc_search).
2436 */
2437 static abort_t lookup_reloc(struct ksplice_mod_change *change,
2438 const struct ksplice_reloc **fingerp,
2439 unsigned long addr,
2440 const struct ksplice_reloc **relocp)
2441 {
2442 const struct ksplice_reloc *r = *fingerp;
2443 int canary_ret;
2444
2445 while (r < change->old_code.relocs_end &&
2446 addr >= r->blank_addr + r->howto->size &&
2447 !(addr == r->blank_addr && r->howto->size == 0))
2448 r++;
2449 *fingerp = r;
2450 if (r == change->old_code.relocs_end)
2451 return NO_MATCH;
2452 if (addr < r->blank_addr)
2453 return NO_MATCH;
2454 *relocp = r;
2455 if (r->howto->type != KSPLICE_HOWTO_RELOC)
2456 return OK;
2457
2458 canary_ret = contains_canary(change, r->blank_addr, r->howto);
2459 if (canary_ret < 0)
2460 return UNEXPECTED;
2461 if (canary_ret == 0) {
2462 ksdebug(change, "run-pre: reloc skipped at p_a=%lx to %s+%lx "
2463 "(altinstr)\n", r->blank_addr, r->symbol->label,
2464 r->target_addend);
2465 return NO_MATCH;
2466 }
2467 if (addr != r->blank_addr) {
2468 ksdebug(change, "Invalid nonzero relocation offset\n");
2469 return UNEXPECTED;
2470 }
2471 return OK;
2472 }
2473
2474 static abort_t handle_howto_symbol(struct ksplice_mod_change *change,
2475 const struct ksplice_reloc *r,
2476 unsigned long run_addr,
2477 enum run_pre_mode mode)
2478 {
2479 if (mode == RUN_PRE_INITIAL)
2480 ksdebug(change, "run-pre: symbol %s at %lx\n", r->symbol->label,
2481 run_addr);
2482 return create_labelval(change, r->symbol, run_addr, TEMP);
2483 }
2484
2485 static abort_t handle_reloc(struct ksplice_mod_change *change,
2486 const struct ksplice_section *sect,
2487 const struct ksplice_reloc *r,
2488 unsigned long run_addr, enum run_pre_mode mode)
2489 {
2490 switch (r->howto->type) {
2491 case KSPLICE_HOWTO_RELOC:
2492 return handle_howto_reloc(change, sect, r, run_addr, mode);
2493 case KSPLICE_HOWTO_DATE:
2494 case KSPLICE_HOWTO_TIME:
2495 return handle_howto_date(change, sect, r, run_addr, mode);
2496 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
2497 #ifdef CONFIG_BUG
2498 case KSPLICE_HOWTO_BUG:
2499 return handle_bug(change, r, run_addr);
2500 #endif /* CONFIG_BUG */
2501 #else /* LINUX_VERSION_CODE < */
2502 /* 7664c5a1da4711bb6383117f51b94c8dc8f3f1cd was after 2.6.19 */
2503 #endif /* LINUX_VERSION_CODE */
2504 case KSPLICE_HOWTO_EXTABLE:
2505 return handle_extable(change, r, run_addr);
2506 case KSPLICE_HOWTO_SYMBOL:
2507 return handle_howto_symbol(change, r, run_addr, mode);
2508 default:
2509 ksdebug(change, "Unexpected howto type %d\n", r->howto->type);
2510 return UNEXPECTED;
2511 }
2512 }
2513
2514 /*
2515 * For date/time relocations, we check that the sequence of bytes
2516 * matches the format of a date or time.
2517 */
2518 static abort_t handle_howto_date(struct ksplice_mod_change *change,
2519 const struct ksplice_section *sect,
2520 const struct ksplice_reloc *r,
2521 unsigned long run_addr, enum run_pre_mode mode)
2522 {
2523 abort_t ret;
2524 char *buf = kmalloc(r->howto->size, GFP_KERNEL);
2525
2526 if (buf == NULL)
2527 return OUT_OF_MEMORY;
2528 if (probe_kernel_read(buf, (void *)run_addr, r->howto->size) == -EFAULT) {
2529 ret = NO_MATCH;
2530 goto out;
2531 }
2532
2533 switch (r->howto->type) {
2534 case KSPLICE_HOWTO_TIME:
2535 if (isdigit(buf[0]) && isdigit(buf[1]) && buf[2] == ':' &&
2536 isdigit(buf[3]) && isdigit(buf[4]) && buf[5] == ':' &&
2537 isdigit(buf[6]) && isdigit(buf[7]))
2538 ret = OK;
2539 else
2540 ret = NO_MATCH;
2541 break;
2542 case KSPLICE_HOWTO_DATE:
2543 if (isalpha(buf[0]) && isalpha(buf[1]) && isalpha(buf[2]) &&
2544 buf[3] == ' ' && (buf[4] == ' ' || isdigit(buf[4])) &&
2545 isdigit(buf[5]) && buf[6] == ' ' && isdigit(buf[7]) &&
2546 isdigit(buf[8]) && isdigit(buf[9]) && isdigit(buf[10]))
2547 ret = OK;
2548 else
2549 ret = NO_MATCH;
2550 break;
2551 default:
2552 ret = UNEXPECTED;
2553 }
2554 if (ret == NO_MATCH && mode == RUN_PRE_INITIAL)
2555 ksdebug(change, "%s string: \"%.*s\" does not match format\n",
2556 r->howto->type == KSPLICE_HOWTO_DATE ? "date" : "time",
2557 r->howto->size, buf);
2558
2559 if (ret != OK)
2560 goto out;
2561 ret = create_labelval(change, r->symbol, run_addr, TEMP);
2562 out:
2563 kfree(buf);
2564 return ret;
2565 }
2566
2567 /*
2568 * Extract the value of a symbol used in a relocation in the pre code
2569 * during run-pre matching, giving an error if it conflicts with a
2570 * previously found value of that symbol
2571 */
2572 static abort_t handle_howto_reloc(struct ksplice_mod_change *change,
2573 const struct ksplice_section *sect,
2574 const struct ksplice_reloc *r,
2575 unsigned long run_addr,
2576 enum run_pre_mode mode)
2577 {
2578 struct ksplice_section *sym_sect = symbol_section(change, r->symbol);
2579 unsigned long offset = r->target_addend;
2580 unsigned long val;
2581 abort_t ret;
2582
2583 ret = read_reloc_value(change, r, run_addr, &val);
2584 if (ret != OK)
2585 return ret;
2586 if (r->howto->pcrel)
2587 val += run_addr;
2588
2589 #ifndef CONFIG_FUNCTION_DATA_SECTIONS
2590 if (sym_sect == NULL || sym_sect->match_map == NULL || offset == 0) {
2591 ;
2592 } else if (offset < 0 || offset >= sym_sect->size) {
2593 ksdebug(change, "Out of range relocation: %s+%lx -> %s+%lx",
2594 sect->symbol->label, r->blank_addr - sect->address,
2595 r->symbol->label, offset);
2596 return NO_MATCH;
2597 } else if (sect == sym_sect && sect->match_map[offset] == NULL) {
2598 sym_sect->match_map[offset] =
2599 (const unsigned char *)r->symbol->value + offset;
2600 } else if (sect == sym_sect && (unsigned long)sect->match_map[offset] ==
2601 r->symbol->value + offset) {
2602 ;
2603 } else if (sect == sym_sect) {
2604 ksdebug(change, "Relocations to nonmatching locations within "
2605 "section %s: %lx does not match %lx\n",
2606 sect->symbol->label, offset,
2607 (unsigned long)sect->match_map[offset] -
2608 r->symbol->value);
2609 return NO_MATCH;
2610 } else if ((sym_sect->flags & KSPLICE_SECTION_MATCHED) == 0) {
2611 if (mode == RUN_PRE_INITIAL)
2612 ksdebug(change, "Delaying matching of %s due to reloc "
2613 "from to unmatching section: %s+%lx\n",
2614 sect->symbol->label, r->symbol->label, offset);
2615 return NO_MATCH;
2616 } else if (sym_sect->match_map[offset] == NULL) {
2617 if (mode == RUN_PRE_INITIAL)
2618 ksdebug(change, "Relocation not to instruction "
2619 "boundary: %s+%lx -> %s+%lx",
2620 sect->symbol->label, r->blank_addr -
2621 sect->address, r->symbol->label, offset);
2622 return NO_MATCH;
2623 } else if ((unsigned long)sym_sect->match_map[offset] !=
2624 r->symbol->value + offset) {
2625 if (mode == RUN_PRE_INITIAL)
2626 ksdebug(change, "Match map shift %s+%lx: %lx != %lx\n",
2627 r->symbol->label, offset,
2628 r->symbol->value + offset,
2629 (unsigned long)sym_sect->match_map[offset]);
2630 val += r->symbol->value + offset -
2631 (unsigned long)sym_sect->match_map[offset];
2632 }
2633 #endif /* !CONFIG_FUNCTION_DATA_SECTIONS */
2634
2635 if (mode == RUN_PRE_INITIAL)
2636 ksdebug(change, "run-pre: reloc at r_a=%lx p_a=%lx to %s+%lx: "
2637 "found %s = %lx\n", run_addr, r->blank_addr,
2638 r->symbol->label, offset, r->symbol->label, val);
2639
2640 if (contains_canary(change, run_addr, r->howto) != 0) {
2641 ksdebug(change, "Aborted. Unexpected canary in run code at %lx"
2642 "\n", run_addr);
2643 return UNEXPECTED;
2644 }
2645
2646 if ((sect->flags & KSPLICE_SECTION_DATA) != 0 &&
2647 sect->symbol == r->symbol)
2648 return OK;
2649 ret = create_labelval(change, r->symbol, val, TEMP);
2650 if (ret == NO_MATCH && mode == RUN_PRE_INITIAL)
2651 ksdebug(change, "run-pre: reloc at r_a=%lx p_a=%lx: labelval "
2652 "%s = %lx does not match expected %lx\n", run_addr,
2653 r->blank_addr, r->symbol->label, r->symbol->value, val);
2654
2655 if (ret != OK)
2656 return ret;
2657 if (sym_sect != NULL && (sym_sect->flags & KSPLICE_SECTION_MATCHED) == 0
2658 && (sym_sect->flags & KSPLICE_SECTION_STRING) != 0) {
2659 if (mode == RUN_PRE_INITIAL)
2660 ksdebug(change, "Recursively comparing string section "
2661 "%s\n", sym_sect->symbol->label);
2662 else if (mode == RUN_PRE_DEBUG)
2663 ksdebug(change, "[str start] ");
2664 ret = run_pre_cmp(change, sym_sect, val, NULL, mode);
2665 if (mode == RUN_PRE_DEBUG)
2666 ksdebug(change, "[str end] ");
2667 if (ret == OK && mode == RUN_PRE_INITIAL)
2668 ksdebug(change, "Successfully matched string section %s"
2669 "\n", sym_sect->symbol->label);
2670 else if (mode == RUN_PRE_INITIAL)
2671 ksdebug(change, "Failed to match string section %s\n",
2672 sym_sect->symbol->label);
2673 }
2674 return ret;
2675 }
2676
2677 #ifdef CONFIG_GENERIC_BUG
2678 #ifdef KSPLICE_NO_KERNEL_SUPPORT
2679 EXTRACT_SYMBOL(find_bug);
2680 #endif /* KSPLICE_NO_KERNEL_SUPPORT */
2681 static abort_t handle_bug(struct ksplice_mod_change *change,
2682 const struct ksplice_reloc *r, unsigned long run_addr)
2683 {
2684 const struct bug_entry *run_bug = find_bug(run_addr);
2685 struct ksplice_section *bug_sect = symbol_section(change, r->symbol);
2686 if (run_bug == NULL)
2687 return NO_MATCH;
2688 if (bug_sect == NULL)
2689 return UNEXPECTED;
2690 return create_labelval(change, bug_sect->symbol, (unsigned long)run_bug,
2691 TEMP);
2692 }
2693 #endif /* CONFIG_GENERIC_BUG */
2694
2695 #ifdef KSPLICE_NO_KERNEL_SUPPORT
2696 EXTRACT_SYMBOL(search_exception_tables);
2697 #endif /* KSPLICE_NO_KERNEL_SUPPORT */
2698
2699 static abort_t handle_extable(struct ksplice_mod_change *change,
2700 const struct ksplice_reloc *r,
2701 unsigned long run_addr)
2702 {
2703 const struct exception_table_entry *run_ent =
2704 search_exception_tables(run_addr);
2705 struct ksplice_section *ex_sect = symbol_section(change, r->symbol);
2706 if (run_ent == NULL)
2707 return NO_MATCH;
2708 if (ex_sect == NULL)
2709 return UNEXPECTED;
2710 return create_labelval(change, ex_sect->symbol, (unsigned long)run_ent,
2711 TEMP);
2712 }
2713
2714 static int symbol_section_bsearch_compare(const void *a, const void *b)
2715 {
2716 const struct ksplice_symbol *sym = a;
2717 const struct ksplice_section *sect = b;
2718 return strcmp(sym->label, sect->symbol->label);
2719 }
2720
2721 static int compare_section_labels(const void *va, const void *vb)
2722 {
2723 const struct ksplice_section *a = va, *b = vb;
2724 return strcmp(a->symbol->label, b->symbol->label);
2725 }
2726
2727 static struct ksplice_section *symbol_section(struct ksplice_mod_change *change,
2728 const struct ksplice_symbol *sym)
2729 {
2730 return bsearch(sym, change->old_code.sections,
2731 change->old_code.sections_end -
2732 change->old_code.sections,
2733 sizeof(struct ksplice_section),
2734 symbol_section_bsearch_compare);
2735 }
2736
2737 /* Find the relocation for the oldaddr of a ksplice_patch */
2738 static const struct ksplice_reloc *
2739 patch_reloc(struct ksplice_mod_change *change,
2740 const struct ksplice_patch *p)
2741 {
2742 unsigned long addr = (unsigned long)&p->oldaddr;
2743 const struct ksplice_reloc *r =
2744 find_reloc(change->new_code.relocs, change->new_code.relocs_end,
2745 addr, sizeof(addr));
2746 if (r == NULL || r->blank_addr < addr ||
2747 r->blank_addr >= addr + sizeof(addr))
2748 return NULL;
2749 return r;
2750 }
2751
2752 /*
2753 * Populates vals with the possible values for ksym from the various
2754 * sources Ksplice uses to resolve symbols
2755 */
2756 static abort_t lookup_symbol(struct ksplice_mod_change *change,
2757 const struct ksplice_symbol *ksym,
2758 struct list_head *vals)
2759 {
2760 abort_t ret;
2761
2762 #ifdef KSPLICE_STANDALONE
2763 if (!bootstrapped)
2764 return OK;
2765 #endif /* KSPLICE_STANDALONE */
2766
2767 if (ksym->candidate_vals == NULL) {
2768 release_vals(vals);
2769 ksdebug(change, "using detected sym %s=%lx\n", ksym->label,
2770 ksym->value);
2771 return add_candidate_val(change, vals, ksym->value);
2772 }
2773
2774 #ifdef CONFIG_MODULE_UNLOAD
2775 if (strcmp(ksym->label, "cleanup_module") == 0 && change->target != NULL
2776 && change->target->exit != NULL) {
2777 ret = add_candidate_val(change, vals,
2778 (unsigned long)change->target->exit);
2779 if (ret != OK)
2780 return ret;
2781 }
2782 #endif
2783
2784 if (ksym->name != NULL) {
2785 struct candidate_val *val;
2786 list_for_each_entry(val, ksym->candidate_vals, list) {
2787 ret = add_candidate_val(change, vals, val->val);
2788 if (ret != OK)
2789 return ret;
2790 }
2791
2792 ret = new_export_lookup(change, ksym->name, vals);
2793 if (ret != OK)
2794 return ret;
2795 }
2796
2797 return OK;
2798 }
2799
2800 #ifdef KSPLICE_STANDALONE
2801 static abort_t
2802 add_system_map_candidates(struct ksplice_mod_change *change,
2803 const struct ksplice_system_map *start,
2804 const struct ksplice_system_map *end,
2805 const char *label, struct list_head *vals)
2806 {
2807 abort_t ret;
2808 long off;
2809 int i;
2810 const struct ksplice_system_map *smap;
2811
2812 /* Some Fedora kernel releases have System.map files whose symbol
2813 * addresses disagree with the running kernel by a constant address
2814 * offset because of the CONFIG_PHYSICAL_START and CONFIG_PHYSICAL_ALIGN
2815 * values used to compile these kernels. This constant address offset
2816 * is always a multiple of 0x100000.
2817 *
2818 * If we observe an offset that is NOT a multiple of 0x100000, then the
2819 * user provided us with an incorrect System.map file, and we should
2820 * abort.
2821 * If we observe an offset that is a multiple of 0x100000, then we can
2822 * adjust the System.map address values accordingly and proceed.
2823 */
2824 off = (unsigned long)printk - change->map_printk;
2825 if (off & 0xfffff) {
2826 ksdebug(change,
2827 "Aborted. System.map does not match kernel.\n");
2828 return BAD_SYSTEM_MAP;
2829 }
2830
2831 smap = bsearch(label, start, end - start, sizeof(*smap),
2832 system_map_bsearch_compare);
2833 if (smap == NULL)
2834 return OK;
2835
2836 for (i = 0; i < smap->nr_candidates; i++) {
2837 ret = add_candidate_val(change, vals,
2838 smap->candidates[i] + off);
2839 if (ret != OK)
2840 return ret;
2841 }
2842 return OK;
2843 }
2844
2845 static int system_map_bsearch_compare(const void *key, const void *elt)
2846 {
2847 const struct ksplice_system_map *map = elt;
2848 const char *label = key;
2849 return strcmp(label, map->label);
2850 }
2851 #endif /* !KSPLICE_STANDALONE */
2852
2853 /*
2854 * An update could one module to export a symbol and at the same time
2855 * change another module to use that symbol. This violates the normal
2856 * situation where the changes can be handled independently.
2857 *
2858 * new_export_lookup obtains symbol values from the changes to the
2859 * exported symbol table made by other changes.
2860 */
2861 static abort_t new_export_lookup(struct ksplice_mod_change *ichange,
2862 const char *name, struct list_head *vals)
2863 {
2864 struct ksplice_mod_change *change;
2865 struct ksplice_patch *p;
2866 list_for_each_entry(change, &ichange->update->changes, list) {
2867 for (p = change->patches; p < change->patches_end; p++) {
2868 const struct kernel_symbol *sym;
2869 const struct ksplice_reloc *r;
2870 if (p->type != KSPLICE_PATCH_EXPORT ||
2871 strcmp(name, *(const char **)p->contents) != 0)
2872 continue;
2873
2874 /* Check that the p->oldaddr reloc has been resolved. */
2875 r = patch_reloc(change, p);
2876 if (r == NULL ||
2877 contains_canary(change, r->blank_addr,
2878 r->howto) != 0)
2879 continue;
2880 sym = (const struct kernel_symbol *)r->symbol->value;
2881
2882 /*
2883 * Check that the sym->value reloc has been resolved,
2884 * if there is a Ksplice relocation there.
2885 */
2886 r = find_reloc(change->new_code.relocs,
2887 change->new_code.relocs_end,
2888 (unsigned long)&sym->value,
2889 sizeof(&sym->value));
2890 if (r != NULL &&
2891 r->blank_addr == (unsigned long)&sym->value &&
2892 contains_canary(change, r->blank_addr,
2893 r->howto) != 0)
2894 continue;
2895 return add_candidate_val(ichange, vals, sym->value);
2896 }
2897 }
2898 return OK;
2899 }
2900
2901 #ifdef KSPLICE_STANDALONE
2902 EXTRACT_SYMBOL(bust_spinlocks);
2903 #endif /* KSPLICE_STANDALONE */
2904
2905 /*
2906 * When patch_action is called, the update should be fully prepared.
2907 * patch_action will try to actually insert or remove trampolines for
2908 * the update.
2909 */
2910 static abort_t patch_action(struct update *update, enum ksplice_action action)
2911 {
2912 static int (*const __patch_actions[KS_ACTIONS])(void *) = {
2913 [KS_APPLY] = __apply_patches,
2914 [KS_REVERSE] = __reverse_patches,
2915 };
2916 int i;
2917 abort_t ret;
2918 struct ksplice_mod_change *change;
2919
2920 ret = map_trampoline_pages(update);
2921 if (ret != OK)
2922 return ret;
2923
2924 list_for_each_entry(change, &update->changes, list) {
2925 const typeof(int (*)(void)) *f;
2926 for (f = change->hooks[action].pre;
2927 f < change->hooks[action].pre_end; f++) {
2928 if ((*f)() != 0) {
2929 ret = CALL_FAILED;
2930 goto out;
2931 }
2932 }
2933 }
2934
2935 for (i = 0; i < 5; i++) {
2936 cleanup_conflicts(update);
2937 #ifdef KSPLICE_STANDALONE
2938 bust_spinlocks(1);
2939 #endif /* KSPLICE_STANDALONE */
2940 ret = (__force abort_t)stop_machine(__patch_actions[action],
2941 update, NULL);
2942 #ifdef KSPLICE_STANDALONE
2943 bust_spinlocks(0);
2944 #endif /* KSPLICE_STANDALONE */
2945 if (ret != CODE_BUSY)
2946 break;
2947 set_current_state(TASK_INTERRUPTIBLE);
2948 schedule_timeout(msecs_to_jiffies(1000));
2949 }
2950 out:
2951 unmap_trampoline_pages(update);
2952
2953 if (ret == CODE_BUSY) {
2954 print_conflicts(update);
2955 _ksdebug(update, "Aborted %s. stack check: to-be-%s "
2956 "code is busy.\n", update->kid,
2957 action == KS_APPLY ? "replaced" : "reversed");
2958 } else if (ret == ALREADY_REVERSED) {
2959 _ksdebug(update, "Aborted %s. Ksplice update %s is already "
2960 "reversed.\n", update->kid, update->kid);
2961 } else if (ret == MODULE_BUSY) {
2962 _ksdebug(update, "Update %s is in use by another module\n",
2963 update->kid);
2964 }
2965
2966 if (ret != OK) {
2967 list_for_each_entry(change, &update->changes, list) {
2968 const typeof(void (*)(void)) *f;
2969 for (f = change->hooks[action].fail;
2970 f < change->hooks[action].fail_end; f++)
2971 (*f)();
2972 }
2973
2974 return ret;
2975 }
2976
2977 list_for_each_entry(change, &update->changes, list) {
2978 const typeof(void (*)(void)) *f;
2979 for (f = change->hooks[action].post;
2980 f < change->hooks[action].post_end; f++)
2981 (*f)();
2982 }
2983
2984 _ksdebug(update, "Atomic patch %s for %s complete\n",
2985 action == KS_APPLY ? "insertion" : "removal", update->kid);
2986 return OK;
2987 }
2988
2989 /* Atomically insert the update; run from within stop_machine */
2990 static int __apply_patches(void *updateptr)
2991 {
2992 struct update *update = updateptr;
2993 struct ksplice_mod_change *change;
2994 struct ksplice_module_list_entry *entry;
2995 struct ksplice_patch *p;
2996 abort_t ret;
2997
2998 if (update->stage == STAGE_APPLIED)
2999 return (__force int)OK;
3000
3001 if (update->stage != STAGE_PREPARING)
3002 return (__force int)UNEXPECTED;
3003
3004 ret = check_each_task(update);
3005 if (ret != OK)
3006 return (__force int)ret;
3007
3008 list_for_each_entry(change, &update->changes, list) {
3009 if (try_module_get(change->new_code_mod) != 1) {
3010 struct ksplice_mod_change *change1;
3011 list_for_each_entry(change1, &update->changes, list) {
3012 if (change1 == change)
3013 break;
3014 module_put(change1->new_code_mod);
3015 }
3016 module_put(THIS_MODULE);
3017 return (__force int)UNEXPECTED;
3018 }
3019 }
3020
3021 list_for_each_entry(change, &update->changes, list) {
3022 const typeof(int (*)(void)) *f;
3023 for (f = change->hooks[KS_APPLY].check;
3024 f < change->hooks[KS_APPLY].check_end; f++) {
3025 if ((*f)() != 0)
3026 return (__force int)CALL_FAILED;
3027 }
3028 }
3029
3030 /* Commit point: the update application will succeed. */
3031
3032 update->stage = STAGE_APPLIED;
3033 #ifdef TAINT_KSPLICE
3034 add_taint(TAINT_KSPLICE);
3035 #endif
3036
3037 list_for_each_entry(entry, &update->ksplice_module_list, update_list)
3038 list_add(&entry->list, &ksplice_modules);
3039
3040 list_for_each_entry(change, &update->changes, list) {
3041 for (p = change->patches; p < change->patches_end; p++)
3042 insert_trampoline(p);
3043 }
3044
3045 list_for_each_entry(change, &update->changes, list) {
3046 const typeof(void (*)(void)) *f;
3047 for (f = change->hooks[KS_APPLY].intra;
3048 f < change->hooks[KS_APPLY].intra_end; f++)
3049 (*f)();
3050 }
3051
3052 return (__force int)OK;
3053 }
3054
3055 /* Atomically remove the update; run from within stop_machine */
3056 static int __reverse_patches(void *updateptr)
3057 {
3058 struct update *update = updateptr;
3059 struct ksplice_mod_change *change;
3060 struct ksplice_module_list_entry *entry;
3061 const struct ksplice_patch *p;
3062 abort_t ret;
3063
3064 if (update->stage != STAGE_APPLIED)
3065 return (__force int)OK;
3066
3067 #ifdef CONFIG_MODULE_UNLOAD
3068 list_for_each_entry(change, &update->changes, list) {
3069 if (module_refcount(change->new_code_mod) != 1)
3070 return (__force int)MODULE_BUSY;
3071 }
3072 #endif /* CONFIG_MODULE_UNLOAD */
3073
3074 list_for_each_entry(entry, &update->ksplice_module_list, update_list) {
3075 if (!entry->applied &&
3076 find_module(entry->target_mod_name) != NULL)
3077 return COLD_UPDATE_LOADED;
3078 }
3079
3080 ret = check_each_task(update);
3081 if (ret != OK)
3082 return (__force int)ret;
3083
3084 list_for_each_entry(change, &update->changes, list) {
3085 for (p = change->patches; p < change->patches_end; p++) {
3086 ret = verify_trampoline(change, p);
3087 if (ret != OK)
3088 return (__force int)ret;
3089 }
3090 }
3091
3092 list_for_each_entry(change, &update->changes, list) {
3093 const typeof(int (*)(void)) *f;
3094 for (f = change->hooks[KS_REVERSE].check;
3095 f < change->hooks[KS_REVERSE].check_end; f++) {
3096 if ((*f)() != 0)
3097 return (__force int)CALL_FAILED;
3098 }
3099 }
3100
3101 /* Commit point: the update reversal will succeed. */
3102
3103 update->stage = STAGE_REVERSED;
3104
3105 list_for_each_entry(change, &update->changes, list)
3106 module_put(change->new_code_mod);
3107
3108 list_for_each_entry(entry, &update->ksplice_module_list, update_list)
3109 list_del(&entry->list);
3110
3111 list_for_each_entry(change, &update->changes, list) {
3112 const typeof(void (*)(void)) *f;
3113 for (f = change->hooks[KS_REVERSE].intra;
3114 f < change->hooks[KS_REVERSE].intra_end; f++)
3115 (*f)();
3116 }
3117
3118 list_for_each_entry(change, &update->changes, list) {
3119 for (p = change->patches; p < change->patches_end; p++)
3120 remove_trampoline(p);
3121 }
3122
3123 return (__force int)OK;
3124 }
3125
3126 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11)
3127 /* 5d4564e68210e4b1edb3f013bc3e59982bb35737 was after 2.6.10 */
3128 EXTRACT_SYMBOL(tasklist_lock);
3129 #endif /* LINUX_VERSION_CODE */
3130
3131 /*
3132 * Check whether any thread's instruction pointer or any address of
3133 * its stack is contained in one of the safety_records associated with
3134 * the update.
3135 *
3136 * check_each_task must be called from inside stop_machine, because it
3137 * does not take tasklist_lock (which cannot be held by anyone else
3138 * during stop_machine).
3139 */
3140 static abort_t check_each_task(struct update *update)
3141 {
3142 const struct task_struct *g, *p;
3143 abort_t status = OK, ret;
3144 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11)
3145 /* 5d4564e68210e4b1edb3f013bc3e59982bb35737 was after 2.6.10 */
3146 read_lock(&tasklist_lock);
3147 #endif /* LINUX_VERSION_CODE */
3148 do_each_thread(g, p) {
3149 /* do_each_thread is a double loop! */
3150 ret = check_task(update, p, false);
3151 if (ret != OK) {
3152 check_task(update, p, true);
3153 status = ret;
3154 }
3155 if (ret != OK && ret != CODE_BUSY)
3156 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11)
3157 /* 5d4564e68210e4b1edb3f013bc3e59982bb35737 was after 2.6.10 */
3158 goto out;
3159 #else /* LINUX_VERSION_CODE < */
3160 return ret;
3161 #endif /* LINUX_VERSION_CODE */
3162 } while_each_thread(g, p);
3163 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11)
3164 /* 5d4564e68210e4b1edb3f013bc3e59982bb35737 was after 2.6.10 */
3165 out:
3166 read_unlock(&tasklist_lock);
3167 #endif /* LINUX_VERSION_CODE */
3168 return status;
3169 }
3170
3171 #ifdef KSPLICE_NO_KERNEL_SUPPORT
3172 EXTRACT_SYMBOL(task_curr);
3173 #endif /* KSPLICE_NO_KERNEL_SUPPORT */
3174
3175 static abort_t check_task(struct update *update,
3176 const struct task_struct *t, bool rerun)
3177 {
3178 abort_t status, ret;
3179 struct conflict *conf = NULL;
3180
3181 if (rerun) {
3182 conf = kmalloc(sizeof(*conf), GFP_ATOMIC);
3183 if (conf == NULL)
3184 return OUT_OF_MEMORY;
3185 conf->process_name = kstrdup(t->comm, GFP_ATOMIC);
3186 if (conf->process_name == NULL) {
3187 kfree(conf);
3188 return OUT_OF_MEMORY;
3189 }
3190 conf->pid = t->pid;
3191 INIT_LIST_HEAD(&conf->stack);
3192 list_add(&conf->list, &update->conflicts);
3193 }
3194
3195 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)
3196 if (t->state == TASK_DEAD)
3197 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
3198 /* c394cc9fbb367f87faa2228ec2eabacd2d4701c6 was after 2.6.18 */
3199 if ((t->flags & PF_DEAD) != 0)
3200 #endif
3201 return OK;
3202
3203 status = check_address(update, conf, KSPLICE_IP(t));
3204 if (t == current) {
3205 ret = check_stack(update, conf, task_thread_info(t),
3206 (unsigned long *)__builtin_frame_address(0));
3207 if (status == OK)
3208 status = ret;
3209 } else if (!task_curr(t)) {
3210 ret = check_stack(update, conf, task_thread_info(t),
3211 (unsigned long *)KSPLICE_SP(t));
3212 if (status == OK)
3213 status = ret;
3214 } else if (!is_stop_machine(t)) {
3215 status = UNEXPECTED_RUNNING_TASK;
3216 }
3217 return status;
3218 }
3219
3220 static abort_t check_stack(struct update *update, struct conflict *conf,
3221 const struct thread_info *tinfo,
3222 const unsigned long *stack)
3223 {
3224 abort_t status = OK, ret;
3225 unsigned long addr;
3226
3227 while (valid_stack_ptr(tinfo, stack)) {
3228 addr = *stack++;
3229 ret = check_address(update, conf, addr);
3230 if (ret != OK)
3231 status = ret;
3232 }
3233 return status;
3234 }
3235
3236 static abort_t check_address(struct update *update,
3237 struct conflict *conf, unsigned long addr)
3238 {
3239 abort_t status = OK, ret;
3240 const struct safety_record *rec;
3241 struct ksplice_mod_change *change;
3242 struct conflict_addr *ca = NULL;
3243
3244 if (conf != NULL) {
3245 ca = kmalloc(sizeof(*ca), GFP_ATOMIC);
3246 if (ca == NULL)
3247 return OUT_OF_MEMORY;
3248 ca->addr = addr;
3249 ca->has_conflict = false;
3250 ca->label = NULL;
3251 list_add(&ca->list, &conf->stack);
3252 }
3253
3254 list_for_each_entry(change, &update->changes, list) {
3255 unsigned long tramp_addr = follow_trampolines(change, addr);
3256 list_for_each_entry(rec, &change->safety_records, list) {
3257 ret = check_record(ca, rec, tramp_addr);
3258 if (ret != OK)
3259 status = ret;
3260 }
3261 }
3262 return status;
3263 }
3264
3265 static abort_t check_record(struct conflict_addr *ca,
3266 const struct safety_record *rec, unsigned long addr)
3267 {
3268 if (addr >= rec->addr && addr < rec->addr + rec->size) {
3269 if (ca != NULL) {
3270 ca->label = rec->label;
3271 ca->has_conflict = true;
3272 }
3273 return CODE_BUSY;
3274 }
3275 return OK;
3276 }
3277
3278 /* Is the task one of the stop_machine tasks? */
3279 static bool is_stop_machine(const struct task_struct *t)
3280 {
3281 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
3282 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28)
3283 const char *kstop_prefix = "kstop/";
3284 #else /* LINUX_VERSION_CODE < */
3285 /* c9583e55fa2b08a230c549bd1e3c0bde6c50d9cc was after 2.6.27 */
3286 const char *kstop_prefix = "kstop";
3287 #endif /* LINUX_VERSION_CODE */
3288 const char *num;
3289 if (!strstarts(t->comm, kstop_prefix))
3290 return false;
3291 num = t->comm + strlen(kstop_prefix);
3292 return num[strspn(num, "0123456789")] == '\0';
3293 #else /* LINUX_VERSION_CODE < */
3294 /* ffdb5976c47609c862917d4c186ecbb5706d2dda was after 2.6.26 */
3295 return strcmp(t->comm, "kstopmachine") == 0;
3296 #endif /* LINUX_VERSION_CODE */
3297 }
3298
3299 static void cleanup_conflicts(struct update *update)
3300 {
3301 struct conflict *conf;
3302 list_for_each_entry(conf, &update->conflicts, list) {
3303 clear_list(&conf->stack, struct conflict_addr, list);
3304 kfree(conf->process_name);
3305 }
3306 clear_list(&update->conflicts, struct conflict, list);
3307 }
3308
3309 static void print_conflicts(struct update *update)
3310 {
3311 const struct conflict *conf;
3312 const struct conflict_addr *ca;
3313 list_for_each_entry(conf, &update->conflicts, list) {
3314 _ksdebug(update, "stack check: pid %d (%s):", conf->pid,
3315 conf->process_name);
3316 list_for_each_entry(ca, &conf->stack, list) {
3317 _ksdebug(update, " %lx", ca->addr);
3318 if (ca->has_conflict)
3319 _ksdebug(update, " [<-CONFLICT]");
3320 }
3321 _ksdebug(update, "\n");
3322 }
3323 }
3324
3325 static void insert_trampoline(struct ksplice_patch *p)
3326 {
3327 mm_segment_t old_fs = get_fs();
3328 set_fs(KERNEL_DS);
3329 memcpy(p->saved, p->vaddr, p->size);
3330 memcpy(p->vaddr, p->contents, p->size);
3331 flush_icache_range(p->oldaddr, p->oldaddr + p->size);
3332 set_fs(old_fs);
3333 }
3334
3335 static abort_t verify_trampoline(struct ksplice_mod_change *change,
3336 const struct ksplice_patch *p)
3337 {
3338 if (memcmp(p->vaddr, p->contents, p->size) != 0) {
3339 ksdebug(change, "Aborted. Trampoline at %lx has been "
3340 "overwritten.\n", p->oldaddr);
3341 return CODE_BUSY;
3342 }
3343 return OK;
3344 }
3345
3346 static void remove_trampoline(const struct ksplice_patch *p)
3347 {
3348 mm_segment_t old_fs = get_fs();
3349 set_fs(KERNEL_DS);
3350 memcpy(p->vaddr, p->saved, p->size);
3351 flush_icache_range(p->oldaddr, p->oldaddr + p->size);
3352 set_fs(old_fs);
3353 }
3354
3355 /* Returns NO_MATCH if there's already a labelval with a different value */
3356 static abort_t create_labelval(struct ksplice_mod_change *change,
3357 struct ksplice_symbol *ksym,
3358 unsigned long val, int status)
3359 {
3360 val = follow_trampolines(change, val);
3361 if (ksym->candidate_vals == NULL)
3362 return ksym->value == val ? OK : NO_MATCH;
3363
3364 ksym->value = val;
3365 if (status == TEMP) {
3366 struct labelval *lv = kmalloc(sizeof(*lv), GFP_KERNEL);
3367 if (lv == NULL)
3368 return OUT_OF_MEMORY;
3369 lv->symbol = ksym;
3370 lv->saved_vals = ksym->candidate_vals;
3371 list_add(&lv->list, &change->temp_labelvals);
3372 }
3373 ksym->candidate_vals = NULL;
3374 return OK;
3375 }
3376
3377 /*
3378 * Creates a new safety_record for a old_code section based on its
3379 * ksplice_section and run-pre matching information.
3380 */
3381 static abort_t create_safety_record(struct ksplice_mod_change *change,
3382 const struct ksplice_section *sect,
3383 struct list_head *record_list,
3384 unsigned long run_addr,
3385 unsigned long run_size)
3386 {
3387 struct safety_record *rec;
3388 struct ksplice_patch *p;
3389
3390 if (record_list == NULL)
3391 return OK;
3392
3393 for (p = change->patches; p < change->patches_end; p++) {
3394 const struct ksplice_reloc *r = patch_reloc(change, p);
3395 if (strcmp(sect->symbol->label, r->symbol->label) == 0)
3396 break;
3397 }
3398 if (p >= change->patches_end)
3399 return OK;
3400
3401 rec = kmalloc(sizeof(*rec), GFP_KERNEL);
3402 if (rec == NULL)
3403 return OUT_OF_MEMORY;
3404 /*
3405 * The old_code might be unloaded when checking reversing
3406 * patches, so we need to kstrdup the label here.
3407 */
3408 rec->label = kstrdup(sect->symbol->label, GFP_KERNEL);
3409 if (rec->label == NULL) {
3410 kfree(rec);
3411 return OUT_OF_MEMORY;
3412 }
3413 rec->addr = run_addr;
3414 rec->size = run_size;
3415
3416 list_add(&rec->list, record_list);
3417 return OK;
3418 }
3419
3420 static abort_t add_candidate_val(struct ksplice_mod_change *change,
3421 struct list_head *vals, unsigned long val)
3422 {
3423 struct candidate_val *tmp, *new;
3424
3425 /*
3426 * Careful: follow trampolines before comparing values so that we do
3427 * not mistake the obsolete function for another copy of the function.
3428 */
3429 val = follow_trampolines(change, val);
3430
3431 list_for_each_entry(tmp, vals, list) {
3432 if (tmp->val == val)
3433 return OK;
3434 }
3435 new = kmalloc(sizeof(*new), GFP_KERNEL);
3436 if (new == NULL)
3437 return OUT_OF_MEMORY;
3438 new->val = val;
3439 list_add(&new->list, vals);
3440 return OK;
3441 }
3442
3443 static void release_vals(struct list_head *vals)
3444 {
3445 clear_list(vals, struct candidate_val, list);
3446 }
3447
3448 /*
3449 * The temp_labelvals list is used to cache those temporary labelvals
3450 * that have been created to cross-check the symbol values obtained
3451 * from different relocations within a single section being matched.
3452 *
3453 * If status is VAL, commit the temp_labelvals as final values.
3454 *
3455 * If status is NOVAL, restore the list of possible values to the
3456 * ksplice_symbol, so that it no longer has a known value.
3457 */
3458 static void set_temp_labelvals(struct ksplice_mod_change *change, int status)
3459 {
3460 struct labelval *lv, *n;
3461 list_for_each_entry_safe(lv, n, &change->temp_labelvals, list) {
3462 if (status == NOVAL) {
3463 lv->symbol->candidate_vals = lv->saved_vals;
3464 } else {
3465 release_vals(lv->saved_vals);
3466 kfree(lv->saved_vals);
3467 }
3468 list_del(&lv->list);
3469 kfree(lv);
3470 }
3471 }
3472
3473 /* Is there a Ksplice canary with given howto at blank_addr? */
3474 static int contains_canary(struct ksplice_mod_change *change,
3475 unsigned long blank_addr,
3476 const struct ksplice_reloc_howto *howto)
3477 {
3478 switch (howto->size) {
3479 case 1:
3480 return (*(uint8_t *)blank_addr & howto->dst_mask) ==
3481 (KSPLICE_CANARY & howto->dst_mask);
3482 case 2:
3483 return (*(uint16_t *)blank_addr & howto->dst_mask) ==
3484 (KSPLICE_CANARY & howto->dst_mask);
3485 case 4:
3486 return (*(uint32_t *)blank_addr & howto->dst_mask) ==
3487 (KSPLICE_CANARY & howto->dst_mask);
3488 #if BITS_PER_LONG >= 64
3489 case 8:
3490 return (*(uint64_t *)blank_addr & howto->dst_mask) ==
3491 (KSPLICE_CANARY & howto->dst_mask);
3492 #endif /* BITS_PER_LONG */
3493 default:
3494 ksdebug(change, "Aborted. Invalid relocation size.\n");
3495 return -1;
3496 }
3497 }
3498
3499 #ifdef KSPLICE_NO_KERNEL_SUPPORT
3500 EXTRACT_SYMBOL(__kernel_text_address);
3501 #endif /* KSPLICE_NO_KERNEL_SUPPORT */
3502
3503 /*
3504 * Compute the address of the code you would actually run if you were
3505 * to call the function at addr (i.e., follow the sequence of jumps
3506 * starting at addr)
3507 */
3508 static unsigned long follow_trampolines(struct ksplice_mod_change *change,
3509 unsigned long addr)
3510 {
3511 unsigned long new_addr;
3512 struct module *m;
3513
3514 while (1) {
3515 #ifdef KSPLICE_STANDALONE
3516 if (!bootstrapped)
3517 return addr;
3518 #endif /* KSPLICE_STANDALONE */
3519 if (!__kernel_text_address(addr) ||
3520 trampoline_target(change, addr, &new_addr) != OK)
3521 return addr;
3522 m = __module_text_address(new_addr);
3523 if (m == NULL || m == change->target ||
3524 !strstarts(m->name, "ksplice"))
3525 return addr;
3526 addr = new_addr;
3527 }
3528 }
3529
3530 /* Does module a patch module b? */
3531 static bool patches_module(const struct module *a, const struct module *b)
3532 {
3533 #ifdef KSPLICE_NO_KERNEL_SUPPORT
3534 const char *name;
3535 const char *modname = b == NULL ? "vmlinux" : b->name;
3536 if (a == b)
3537 return true;
3538 if (a == NULL || !strstarts(a->name, "ksplice_"))
3539 return false;
3540 name = a->name + strlen("ksplice_");
3541 name += strcspn(name, "_");
3542 if (name[0] != '_')
3543 return false;
3544 name++;
3545 return strstarts(name, modname) &&
3546 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
3547 strcmp(name + strlen(modname), "_new") == 0;
3548 #else /* LINUX_VERSION_CODE < */
3549 /* 0e8a2de644a93132594f66222a9d48405674eacd was after 2.6.9 */
3550 (strcmp(name + strlen(modname), "_n") == 0
3551 || strcmp(name + strlen(modname), "_new") == 0);
3552 #endif /* LINUX_VERSION_CODE */
3553 #else /* !KSPLICE_NO_KERNEL_SUPPORT */
3554 struct ksplice_module_list_entry *entry;
3555 if (a == b)
3556 return true;
3557 list_for_each_entry(entry, &ksplice_modules, list) {
3558 if (strcmp(entry->target_mod_name, b->name) == 0 &&
3559 strcmp(entry->new_code_mod_name, a->name) == 0)
3560 return true;
3561 }
3562 return false;
3563 #endif /* KSPLICE_NO_KERNEL_SUPPORT */
3564 }
3565
3566 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
3567 /* 66f92cf9d415e96a5bdd6c64de8dd8418595d2fc was after 2.6.29 */
3568 static bool strstarts(const char *str, const char *prefix)
3569 {
3570 return strncmp(str, prefix, strlen(prefix)) == 0;
3571 }
3572 #endif /* LINUX_VERSION_CODE */
3573
3574 static bool singular(struct list_head *list)
3575 {
3576 return !list_empty(list) && list->next->next == list;
3577 }
3578
3579 static void *bsearch(const void *key, const void *base, size_t n,
3580 size_t size, int (*cmp)(const void *key, const void *elt))
3581 {
3582 int start = 0, end = n - 1, mid, result;
3583 if (n == 0)
3584 return NULL;
3585 while (start <= end) {
3586 mid = (start + end) / 2;
3587 result = cmp(key, base + mid * size);
3588 if (result < 0)
3589 end = mid - 1;
3590 else if (result > 0)
3591 start = mid + 1;
3592 else
3593 return (void *)base + mid * size;
3594 }
3595 return NULL;
3596 }
3597
3598 static int compare_relocs(const void *a, const void *b)
3599 {
3600 const struct ksplice_reloc *ra = a, *rb = b;
3601 if (ra->blank_addr > rb->blank_addr)
3602 return 1;
3603 else if (ra->blank_addr < rb->blank_addr)
3604 return -1;
3605 else
3606 return ra->howto->size - rb->howto->size;
3607 }
3608
3609 #ifdef KSPLICE_STANDALONE
3610 static int compare_system_map(const void *a, const void *b)
3611 {
3612 const struct ksplice_system_map *sa = a, *sb = b;
3613 return strcmp(sa->label, sb->label);
3614 }
3615 #endif /* KSPLICE_STANDALONE */
3616
3617 #ifdef CONFIG_DEBUG_FS
3618 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
3619 /* Old kernels don't have debugfs_create_blob */
3620 static ssize_t read_file_blob(struct file *file, char __user *user_buf,
3621 size_t count, loff_t *ppos)
3622 {
3623 struct debugfs_blob_wrapper *blob = file->private_data;
3624 return simple_read_from_buffer(user_buf, count, ppos, blob->data,
3625 blob->size);
3626 }
3627
3628 static int blob_open(struct inode *inode, struct file *file)
3629 {
3630 if (inode->i_private)
3631 file->private_data = inode->i_private;
3632 return 0;
3633 }
3634
3635 static struct file_operations fops_blob = {
3636 .read = read_file_blob,
3637 .open = blob_open,
3638 };
3639
3640 static struct dentry *debugfs_create_blob(const char *name, mode_t mode,
3641 struct dentry *parent,
3642 struct debugfs_blob_wrapper *blob)
3643 {
3644 return debugfs_create_file(name, mode, parent, blob, &fops_blob);
3645 }
3646 #endif /* LINUX_VERSION_CODE */
3647
3648 static abort_t init_debug_buf(struct update *update)
3649 {
3650 update->debug_blob.size = 0;
3651 update->debug_blob.data = NULL;
3652 update->debugfs_dentry =
3653 debugfs_create_blob(update->name, S_IFREG | S_IRUSR, NULL,
3654 &update->debug_blob);
3655 if (update->debugfs_dentry == NULL)
3656 return OUT_OF_MEMORY;
3657 return OK;
3658 }
3659
3660 static void clear_debug_buf(struct update *update)
3661 {
3662 if (update->debugfs_dentry == NULL)
3663 return;
3664 debugfs_remove(update->debugfs_dentry);
3665 update->debugfs_dentry = NULL;
3666 update->debug_blob.size = 0;
3667 vfree(update->debug_blob.data);
3668 update->debug_blob.data = NULL;
3669 }
3670
3671 static int _ksdebug(struct update *update, const char *fmt, ...)
3672 {
3673 va_list args;
3674 unsigned long size, old_size, new_size;
3675
3676 if (update->debug == 0)
3677 return 0;
3678
3679 /* size includes the trailing '\0' */
3680 va_start(args, fmt);
3681 size = 1 + vsnprintf(update->debug_blob.data, 0, fmt, args);
3682 va_end(args);
3683 old_size = update->debug_blob.size == 0 ? 0 :
3684 max(PAGE_SIZE, roundup_pow_of_two(update->debug_blob.size));
3685 new_size = update->debug_blob.size + size == 0 ? 0 :
3686 max(PAGE_SIZE, roundup_pow_of_two(update->debug_blob.size + size));
3687 if (new_size > old_size) {
3688 char *buf = vmalloc(new_size);
3689 if (buf == NULL)
3690 return -ENOMEM;
3691 memcpy(buf, update->debug_blob.data, update->debug_blob.size);
3692 vfree(update->debug_blob.data);
3693 update->debug_blob.data = buf;
3694 }
3695 va_start(args, fmt);
3696 update->debug_blob.size += vsnprintf(update->debug_blob.data +
3697 update->debug_blob.size,
3698 size, fmt, args);
3699 va_end(args);
3700 return 0;
3701 }
3702 #else /* CONFIG_DEBUG_FS */
3703 static abort_t init_debug_buf(struct update *update)
3704 {
3705 return OK;
3706 }
3707
3708 static void clear_debug_buf(struct update *update)
3709 {
3710 return;
3711 }
3712
3713 static int _ksdebug(struct update *update, const char *fmt, ...)
3714 {
3715 va_list args;
3716
3717 if (update->debug == 0)
3718 return 0;
3719
3720 if (!update->debug_continue_line)
3721 printk(KERN_DEBUG "ksplice: ");
3722
3723 va_start(args, fmt);
3724 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,9)
3725 vprintk(fmt, args);
3726 #else /* LINUX_VERSION_CODE < */
3727 /* 683b229286b429244f35726b3c18caec429233bd was after 2.6.8 */
3728 {
3729 char *buf = kvasprintf(GFP_KERNEL, fmt, args);
3730 printk("%s", buf);
3731 kfree(buf);
3732 }
3733 #endif /* LINUX_VERSION_CODE */
3734 va_end(args);
3735
3736 update->debug_continue_line =
3737 fmt[0] == '\0' || fmt[strlen(fmt) - 1] != '\n';
3738 return 0;
3739 }
3740 #endif /* CONFIG_DEBUG_FS */
3741
3742 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30) && defined(CONFIG_KALLSYMS)
3743 /* 75a66614db21007bcc8c37f9c5d5b922981387b9 was after 2.6.29 */
3744 extern unsigned long kallsyms_addresses[];
3745 EXTRACT_SYMBOL(kallsyms_addresses);
3746 extern unsigned long kallsyms_num_syms;
3747 EXTRACT_SYMBOL(kallsyms_num_syms);
3748 extern u8 kallsyms_names[];
3749 EXTRACT_SYMBOL(kallsyms_names);
3750
3751 static int kallsyms_on_each_symbol(int (*fn)(void *, const char *,
3752 struct module *, unsigned long),
3753 void *data)
3754 {
3755 char namebuf[KSYM_NAME_LEN];
3756 unsigned long i;
3757 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
3758 unsigned int off;
3759 #endif /* LINUX_VERSION_CODE */
3760 int ret;
3761
3762 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
3763 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
3764 off = kallsyms_expand_symbol(off, namebuf);
3765 ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
3766 if (ret != 0)
3767 return ret;
3768 }
3769 #else /* LINUX_VERSION_CODE < */
3770 /* 5648d78927ca65e74aadc88a2b1d6431e55e78ec was after 2.6.9 */
3771 char *knames;
3772
3773 for (i = 0, knames = kallsyms_names; i < kallsyms_num_syms; i++) {
3774 unsigned prefix = *knames++;
3775
3776 strlcpy(namebuf + prefix, knames, KSYM_NAME_LEN - prefix);
3777
3778 ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
3779 if (ret != OK)
3780 return ret;
3781
3782 knames += strlen(knames) + 1;
3783 }
3784 #endif /* LINUX_VERSION_CODE */
3785 return module_kallsyms_on_each_symbol(fn, data);
3786 }
3787
3788 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
3789 extern u8 kallsyms_token_table[];
3790 EXTRACT_SYMBOL(kallsyms_token_table);
3791 extern u16 kallsyms_token_index[];
3792 EXTRACT_SYMBOL(kallsyms_token_index);
3793
3794 static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
3795 {
3796 long len, skipped_first = 0;
3797 const u8 *tptr, *data;
3798
3799 data = &kallsyms_names[off];
3800 len = *data;
3801 data++;
3802
3803 off += len + 1;
3804
3805 while (len) {
3806 tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
3807 data++;
3808 len--;
3809
3810 while (*tptr) {
3811 if (skipped_first) {
3812 *result = *tptr;
3813 result++;
3814 } else
3815 skipped_first = 1;
3816 tptr++;
3817 }
3818 }
3819
3820 *result = '\0';
3821
3822 return off;
3823 }
3824 #else /* LINUX_VERSION_CODE < */
3825 /* 5648d78927ca65e74aadc88a2b1d6431e55e78ec was after 2.6.9 */
3826 #endif /* LINUX_VERSION_CODE */
3827
3828 static int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
3829 struct module *,
3830 unsigned long),
3831 void *data)
3832 {
3833 struct module *mod;
3834 unsigned int i;
3835 int ret;
3836
3837 list_for_each_entry(mod, &modules, list) {
3838 for (i = 0; i < mod->num_symtab; i++) {
3839 ret = fn(data, mod->strtab + mod->symtab[i].st_name,
3840 mod, mod->symtab[i].st_value);
3841 if (ret != 0)
3842 return ret;
3843 }
3844 }
3845 return 0;
3846 }
3847 #endif /* LINUX_VERSION_CODE && CONFIG_KALLSYMS */
3848
3849 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
3850 /* c6b37801911d7f4663c99cad8aa230bc934cea82 was after 2.6.29 */
3851 static struct module *find_module(const char *name)
3852 {
3853 struct module *mod;
3854
3855 list_for_each_entry(mod, &modules, list) {
3856 if (strcmp(mod->name, name) == 0)
3857 return mod;
3858 }
3859 return NULL;
3860 }
3861
3862 #ifdef CONFIG_MODULE_UNLOAD
3863 struct module_use {
3864 struct list_head list;
3865 struct module *module_which_uses;
3866 };
3867
3868 /* I'm not yet certain whether we need the strong form of this. */
3869 static inline int strong_try_module_get(struct module *mod)
3870 {
3871 if (mod && mod->state != MODULE_STATE_LIVE)
3872 return -EBUSY;
3873 if (try_module_get(mod))
3874 return 0;
3875 return -ENOENT;
3876 }
3877
3878 /* Does a already use b? */
3879 static int already_uses(struct module *a, struct module *b)
3880 {
3881 struct module_use *use;
3882 list_for_each_entry(use, &b->modules_which_use_me, list) {
3883 if (use->module_which_uses == a)
3884 return 1;
3885 }
3886 return 0;
3887 }
3888
3889 /* Make it so module a uses b. Must be holding module_mutex */
3890 static int use_module(struct module *a, struct module *b)
3891 {
3892 struct module_use *use;
3893 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
3894 /* 270a6c4cad809e92d7b81adde92d0b3d94eeb8ee was after 2.6.20 */
3895 int no_warn;
3896 #endif /* LINUX_VERSION_CODE */
3897 if (b == NULL || already_uses(a, b))
3898 return 1;
3899
3900 if (strong_try_module_get(b) < 0)
3901 return 0;
3902
3903 use = kmalloc(sizeof(*use), GFP_ATOMIC);
3904 if (!use) {
3905 module_put(b);
3906 return 0;
3907 }
3908 use->module_which_uses = a;
3909 list_add(&use->list, &b->modules_which_use_me);
3910 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,21)
3911 /* 270a6c4cad809e92d7b81adde92d0b3d94eeb8ee was after 2.6.20 */
3912 no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
3913 #endif /* LINUX_VERSION_CODE */
3914 return 1;
3915 }
3916 #else /* CONFIG_MODULE_UNLOAD */
3917 static int use_module(struct module *a, struct module *b)
3918 {
3919 return 1;
3920 }
3921 #endif /* CONFIG_MODULE_UNLOAD */
3922
3923 #ifndef CONFIG_MODVERSIONS
3924 #define symversion(base, idx) NULL
3925 #else
3926 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
3927 #endif
3928
3929 static bool each_symbol_in_section(const struct symsearch *arr,
3930 unsigned int arrsize,
3931 struct module *owner,
3932 bool (*fn)(const struct symsearch *syms,
3933 struct module *owner,
3934 unsigned int symnum, void *data),
3935 void *data)
3936 {
3937 unsigned int i, j;
3938
3939 for (j = 0; j < arrsize; j++) {
3940 for (i = 0; i < arr[j].stop - arr[j].start; i++)
3941 if (fn(&arr[j], owner, i, data))
3942 return true;
3943 }
3944
3945 return false;
3946 }
3947
3948 /* Returns true as soon as fn returns true, otherwise false. */
3949 static bool each_symbol(bool (*fn)(const struct symsearch *arr,
3950 struct module *owner,
3951 unsigned int symnum, void *data),
3952 void *data)
3953 {
3954 struct module *mod;
3955 const struct symsearch arr[] = {
3956 { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
3957 NOT_GPL_ONLY, false },
3958 { __start___ksymtab_gpl, __stop___ksymtab_gpl,
3959 __start___kcrctab_gpl,
3960 GPL_ONLY, false },
3961 #ifdef KSPLICE_KSYMTAB_FUTURE_SUPPORT
3962 { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
3963 __start___kcrctab_gpl_future,
3964 WILL_BE_GPL_ONLY, false },
3965 #endif /* KSPLICE_KSYMTAB_FUTURE_SUPPORT */
3966 #ifdef KSPLICE_KSYMTAB_UNUSED_SUPPORT
3967 { __start___ksymtab_unused, __stop___ksymtab_unused,
3968 __start___kcrctab_unused,
3969 NOT_GPL_ONLY, true },
3970 { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
3971 __start___kcrctab_unused_gpl,
3972 GPL_ONLY, true },
3973 #endif /* KSPLICE_KSYMTAB_UNUSED_SUPPORT */
3974 };
3975
3976 if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
3977 return 1;
3978
3979 list_for_each_entry(mod, &modules, list) {
3980 struct symsearch module_arr[] = {
3981 { mod->syms, mod->syms + mod->num_syms, mod->crcs,
3982 NOT_GPL_ONLY, false },
3983 { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
3984 mod->gpl_crcs,
3985 GPL_ONLY, false },
3986 #ifdef KSPLICE_KSYMTAB_FUTURE_SUPPORT
3987 { mod->gpl_future_syms,
3988 mod->gpl_future_syms + mod->num_gpl_future_syms,
3989 mod->gpl_future_crcs,
3990 WILL_BE_GPL_ONLY, false },
3991 #endif /* KSPLICE_KSYMTAB_FUTURE_SUPPORT */
3992 #ifdef KSPLICE_KSYMTAB_UNUSED_SUPPORT
3993 { mod->unused_syms,
3994 mod->unused_syms + mod->num_unused_syms,
3995 mod->unused_crcs,
3996 NOT_GPL_ONLY, true },
3997 { mod->unused_gpl_syms,
3998 mod->unused_gpl_syms + mod->num_unused_gpl_syms,
3999 mod->unused_gpl_crcs,
4000 GPL_ONLY, true },
4001 #endif /* KSPLICE_KSYMTAB_UNUSED_SUPPORT */
4002 };
4003
4004 if (each_symbol_in_section(module_arr, ARRAY_SIZE(module_arr),
4005 mod, fn, data))
4006 return true;
4007 }
4008 return false;
4009 }
4010
4011 struct find_symbol_arg {
4012 /* Input */
4013 const char *name;
4014 bool gplok;
4015 bool warn;
4016
4017 /* Output */
4018 struct module *owner;
4019 const unsigned long *crc;
4020 const struct kernel_symbol *sym;
4021 };
4022
4023 static bool find_symbol_in_section(const struct symsearch *syms,
4024 struct module *owner,
4025 unsigned int symnum, void *data)
4026 {
4027 struct find_symbol_arg *fsa = data;
4028
4029 if (strcmp(syms->start[symnum].name, fsa->name) != 0)
4030 return false;
4031
4032 if (!fsa->gplok) {
4033 if (syms->licence == GPL_ONLY)
4034 return false;
4035 if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
4036 printk(KERN_WARNING "Symbol %s is being used "
4037 "by a non-GPL module, which will not "
4038 "be allowed in the future\n", fsa->name);
4039 printk(KERN_WARNING "Please see the file "
4040 "Documentation/feature-removal-schedule.txt "
4041 "in the kernel source tree for more details.\n");
4042 }
4043 }
4044
4045 #ifdef CONFIG_UNUSED_SYMBOLS
4046 if (syms->unused && fsa->warn) {
4047 printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
4048 "however this module is using it.\n", fsa->name);
4049 printk(KERN_WARNING
4050 "This symbol will go away in the future.\n");
4051 printk(KERN_WARNING
4052 "Please evalute if this is the right api to use and if "
4053 "it really is, submit a report the linux kernel "
4054 "mailinglist together with submitting your code for "
4055 "inclusion.\n");
4056 }
4057 #endif
4058
4059 fsa->owner = owner;
4060 fsa->crc = symversion(syms->crcs, symnum);
4061 fsa->sym = &syms->start[symnum];
4062 return true;
4063 }
4064
4065 /* Find a symbol and return it, along with, (optional) crc and
4066 * (optional) module which owns it */
4067 static const struct kernel_symbol *find_symbol(const char *name,
4068 struct module **owner,
4069 const unsigned long **crc,
4070 bool gplok, bool warn)
4071 {
4072 struct find_symbol_arg fsa;
4073
4074 fsa.name = name;
4075 fsa.gplok = gplok;
4076 fsa.warn = warn;
4077
4078 if (each_symbol(find_symbol_in_section, &fsa)) {
4079 if (owner)
4080 *owner = fsa.owner;
4081 if (crc)
4082 *crc = fsa.crc;
4083 return fsa.sym;
4084 }
4085
4086 return NULL;
4087 }
4088
4089 static inline int within_module_core(unsigned long addr, struct module *mod)
4090 {
4091 return (unsigned long)mod->module_core <= addr &&
4092 addr < (unsigned long)mod->module_core + mod->core_size;
4093 }
4094
4095 static inline int within_module_init(unsigned long addr, struct module *mod)
4096 {
4097 return (unsigned long)mod->module_init <= addr &&
4098 addr < (unsigned long)mod->module_init + mod->init_size;
4099 }
4100
4101 static struct module *__module_address(unsigned long addr)
4102 {
4103 struct module *mod;
4104
4105 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28)
4106 list_for_each_entry_rcu(mod, &modules, list)
4107 #else
4108 /* d72b37513cdfbd3f53f3d485a8c403cc96d2c95f was after 2.6.27 */
4109 list_for_each_entry(mod, &modules, list)
4110 #endif
4111 if (within_module_core(addr, mod) ||
4112 within_module_init(addr, mod))
4113 return mod;
4114 return NULL;
4115 }
4116 #endif /* LINUX_VERSION_CODE */
4117
4118 struct update_attribute {
4119 struct attribute attr;
4120 ssize_t (*show)(struct update *update, char *buf);
4121 ssize_t (*store)(struct update *update, const char *buf, size_t len);
4122 };
4123
4124 static ssize_t update_attr_show(struct kobject *kobj, struct attribute *attr,
4125 char *buf)
4126 {
4127 struct update_attribute *attribute =
4128 container_of(attr, struct update_attribute, attr);
4129 struct update *update = container_of(kobj, struct update, kobj);
4130 if (attribute->show == NULL)
4131 return -EIO;
4132 return attribute->show(update, buf);
4133 }
4134
4135 static ssize_t update_attr_store(struct kobject *kobj, struct attribute *attr,
4136 const char *buf, size_t len)
4137 {
4138 struct update_attribute *attribute =
4139 container_of(attr, struct update_attribute, attr);
4140 struct update *update = container_of(kobj, struct update, kobj);
4141 if (attribute->store == NULL)
4142 return -EIO;
4143 return attribute->store(update, buf, len);
4144 }
4145
4146 static struct sysfs_ops update_sysfs_ops = {
4147 .show = update_attr_show,
4148 .store = update_attr_store,
4149 };
4150
4151 static void update_release(struct kobject *kobj)
4152 {
4153 struct update *update;
4154 update = container_of(kobj, struct update, kobj);
4155 cleanup_ksplice_update(update);
4156 }
4157
4158 static ssize_t stage_show(struct update *update, char *buf)
4159 {
4160 switch (update->stage) {
4161 case STAGE_PREPARING:
4162 return snprintf(buf, PAGE_SIZE, "preparing\n");
4163 case STAGE_APPLIED:
4164 return snprintf(buf, PAGE_SIZE, "applied\n");
4165 case STAGE_REVERSED:
4166 return snprintf(buf, PAGE_SIZE, "reversed\n");
4167 }
4168 return 0;
4169 }
4170
4171 static ssize_t abort_cause_show(struct update *update, char *buf)
4172 {
4173 switch (update->abort_cause) {
4174 case OK:
4175 return snprintf(buf, PAGE_SIZE, "ok\n");
4176 case NO_MATCH:
4177 return snprintf(buf, PAGE_SIZE, "no_match\n");
4178 #ifdef KSPLICE_STANDALONE
4179 case BAD_SYSTEM_MAP:
4180 return snprintf(buf, PAGE_SIZE, "bad_system_map\n");
4181 #endif /* KSPLICE_STANDALONE */
4182 case CODE_BUSY:
4183 return snprintf(buf, PAGE_SIZE, "code_busy\n");
4184 case MODULE_BUSY:
4185 return snprintf(buf, PAGE_SIZE, "module_busy\n");
4186 case OUT_OF_MEMORY:
4187 return snprintf(buf, PAGE_SIZE, "out_of_memory\n");
4188 case FAILED_TO_FIND:
4189 return snprintf(buf, PAGE_SIZE, "failed_to_find\n");
4190 case ALREADY_REVERSED:
4191 return snprintf(buf, PAGE_SIZE, "already_reversed\n");
4192 case MISSING_EXPORT:
4193 return snprintf(buf, PAGE_SIZE, "missing_export\n");
4194 case UNEXPECTED_RUNNING_TASK:
4195 return snprintf(buf, PAGE_SIZE, "unexpected_running_task\n");
4196 case TARGET_NOT_LOADED:
4197 return snprintf(buf, PAGE_SIZE, "target_not_loaded\n");
4198 case CALL_FAILED:
4199 return snprintf(buf, PAGE_SIZE, "call_failed\n");
4200 case COLD_UPDATE_LOADED:
4201 return snprintf(buf, PAGE_SIZE, "cold_update_loaded\n");
4202 case UNEXPECTED:
4203 return snprintf(buf, PAGE_SIZE, "unexpected\n");
4204 default:
4205 return snprintf(buf, PAGE_SIZE, "unknown\n");
4206 }
4207 return 0;
4208 }
4209
4210 static ssize_t conflict_show(struct update *update, char *buf)
4211 {
4212 const struct conflict *conf;
4213 const struct conflict_addr *ca;
4214 int used = 0;
4215 mutex_lock(&module_mutex);
4216 list_for_each_entry(conf, &update->conflicts, list) {
4217 used += snprintf(buf + used, PAGE_SIZE - used, "%s %d",
4218 conf->process_name, conf->pid);
4219 list_for_each_entry(ca, &conf->stack, list) {
4220 if (!ca->has_conflict)
4221 continue;
4222 used += snprintf(buf + used, PAGE_SIZE - used, " %s",
4223 ca->label);
4224 }
4225 used += snprintf(buf + used, PAGE_SIZE - used, "\n");
4226 }
4227 mutex_unlock(&module_mutex);
4228 return used;
4229 }
4230
4231 /* Used to pass maybe_cleanup_ksplice_update to kthread_run */
4232 static int maybe_cleanup_ksplice_update_wrapper(void *updateptr)
4233 {
4234 struct update *update = updateptr;
4235 mutex_lock(&module_mutex);
4236 maybe_cleanup_ksplice_update(update);
4237 mutex_unlock(&module_mutex);
4238 return 0;
4239 }
4240
4241 static ssize_t stage_store(struct update *update, const char *buf, size_t len)
4242 {
4243 enum stage old_stage;
4244 mutex_lock(&module_mutex);
4245 old_stage = update->stage;
4246 if ((strncmp(buf, "applied", len) == 0 ||
4247 strncmp(buf, "applied\n", len) == 0) &&
4248 update->stage == STAGE_PREPARING)
4249 update->abort_cause = apply_update(update);
4250 else if ((strncmp(buf, "reversed", len) == 0 ||
4251 strncmp(buf, "reversed\n", len) == 0) &&
4252 update->stage == STAGE_APPLIED)
4253 update->abort_cause = reverse_update(update);
4254 else if ((strncmp(buf, "cleanup", len) == 0 ||
4255 strncmp(buf, "cleanup\n", len) == 0) &&
4256 update->stage == STAGE_REVERSED)
4257 kthread_run(maybe_cleanup_ksplice_update_wrapper, update,
4258 "ksplice_cleanup_%s", update->kid);
4259
4260 mutex_unlock(&module_mutex);
4261 return len;
4262 }
4263
4264 static ssize_t debug_show(struct update *update, char *buf)
4265 {
4266 return snprintf(buf, PAGE_SIZE, "%d\n", update->debug);
4267 }
4268
4269 static ssize_t debug_store(struct update *update, const char *buf, size_t len)
4270 {
4271 unsigned long l;
4272 int ret = strict_strtoul(buf, 10, &l);
4273 if (ret != 0)
4274 return ret;
4275 update->debug = l;
4276 return len;
4277 }
4278
4279 static ssize_t partial_show(struct update *update, char *buf)
4280 {
4281 return snprintf(buf, PAGE_SIZE, "%d\n", update->partial);
4282 }
4283
4284 static ssize_t partial_store(struct update *update, const char *buf, size_t len)
4285 {
4286 unsigned long l;
4287 int ret = strict_strtoul(buf, 10, &l);
4288 if (ret != 0)
4289 return ret;
4290 update->partial = l;
4291 return len;
4292 }
4293
4294 static struct update_attribute stage_attribute =
4295 __ATTR(stage, 0600, stage_show, stage_store);
4296 static struct update_attribute abort_cause_attribute =
4297 __ATTR(abort_cause, 0400, abort_cause_show, NULL);
4298 static struct update_attribute debug_attribute =
4299 __ATTR(debug, 0600, debug_show, debug_store);
4300 static struct update_attribute partial_attribute =
4301 __ATTR(partial, 0600, partial_show, partial_store);
4302 static struct update_attribute conflict_attribute =
4303 __ATTR(conflicts, 0400, conflict_show, NULL);
4304
4305 static struct attribute *update_attrs[] = {
4306 &stage_attribute.attr,
4307 &abort_cause_attribute.attr,
4308 &debug_attribute.attr,
4309 &partial_attribute.attr,
4310 &conflict_attribute.attr,
4311 NULL
4312 };
4313
4314 static struct kobj_type update_ktype = {
4315 .sysfs_ops = &update_sysfs_ops,
4316 .release = update_release,
4317 .default_attrs = update_attrs,
4318 };
4319
4320 #ifdef KSPLICE_STANDALONE
4321 static int debug;
4322 module_param(debug, int, 0600);
4323 MODULE_PARM_DESC(debug, "Debug level");
4324
4325 extern struct ksplice_system_map ksplice_system_map[], ksplice_system_map_end[];
4326
4327 static struct ksplice_mod_change bootstrap_mod_change = {
4328 .name = "ksplice_" __stringify(KSPLICE_KID),
4329 .kid = "init_" __stringify(KSPLICE_KID),
4330 .target_name = NULL,
4331 .target = NULL,
4332 .map_printk = MAP_PRINTK,
4333 .new_code_mod = THIS_MODULE,
4334 .new_code.system_map = ksplice_system_map,
4335 .new_code.system_map_end = ksplice_system_map_end,
4336 };
4337 #endif /* KSPLICE_STANDALONE */
4338
4339 static int init_ksplice(void)
4340 {
4341 #ifdef KSPLICE_STANDALONE
4342 struct ksplice_mod_change *change = &bootstrap_mod_change;
4343 change->update = init_ksplice_update(change->kid);
4344 sort(change->new_code.system_map,
4345 change->new_code.system_map_end - change->new_code.system_map,
4346 sizeof(struct ksplice_system_map), compare_system_map, NULL);
4347 if (change->update == NULL)
4348 return -ENOMEM;
4349 add_to_update(change, change->update);
4350 change->update->debug = debug;
4351 change->update->abort_cause =
4352 apply_relocs(change, ksplice_init_relocs, ksplice_init_relocs_end);
4353 if (change->update->abort_cause == OK)
4354 bootstrapped = true;
4355 cleanup_ksplice_update(bootstrap_mod_change.update);
4356 #else /* !KSPLICE_STANDALONE */
4357 ksplice_kobj = kobject_create_and_add("ksplice", kernel_kobj);
4358 if (ksplice_kobj == NULL)
4359 return -ENOMEM;
4360 #endif /* KSPLICE_STANDALONE */
4361 return 0;
4362 }
4363
4364 static void cleanup_ksplice(void)
4365 {
4366 #ifndef KSPLICE_STANDALONE
4367 kobject_put(ksplice_kobj);
4368 #endif /* KSPLICE_STANDALONE */
4369 }
4370
4371 module_init(init_ksplice);
4372 module_exit(cleanup_ksplice);
4373
4374 MODULE_AUTHOR("Ksplice, Inc.");
4375 MODULE_DESCRIPTION("Ksplice rebootless update system");
4376 #ifdef KSPLICE_VERSION
4377 MODULE_VERSION(KSPLICE_VERSION);
4378 #endif
4379 MODULE_LICENSE("GPL v2");
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