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percpu: pcpu_embed_first_chunk() should free unused parts after all allocs are complete
[linux-2.6.git] / kernel / module.c
blob78ac6ec1e425f8dc03fe27eccd9beee2a233d90a
1 /*
2 Copyright (C) 2002 Richard Henderson
3 Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19 #include <linux/export.h>
20 #include <linux/moduleloader.h>
21 #include <linux/ftrace_event.h>
22 #include <linux/init.h>
23 #include <linux/kallsyms.h>
24 #include <linux/fs.h>
25 #include <linux/sysfs.h>
26 #include <linux/kernel.h>
27 #include <linux/slab.h>
28 #include <linux/vmalloc.h>
29 #include <linux/elf.h>
30 #include <linux/proc_fs.h>
31 #include <linux/seq_file.h>
32 #include <linux/syscalls.h>
33 #include <linux/fcntl.h>
34 #include <linux/rcupdate.h>
35 #include <linux/capability.h>
36 #include <linux/cpu.h>
37 #include <linux/moduleparam.h>
38 #include <linux/errno.h>
39 #include <linux/err.h>
40 #include <linux/vermagic.h>
41 #include <linux/notifier.h>
42 #include <linux/sched.h>
43 #include <linux/stop_machine.h>
44 #include <linux/device.h>
45 #include <linux/string.h>
46 #include <linux/mutex.h>
47 #include <linux/rculist.h>
48 #include <asm/uaccess.h>
49 #include <asm/cacheflush.h>
50 #include <asm/mmu_context.h>
51 #include <linux/license.h>
52 #include <asm/sections.h>
53 #include <linux/tracepoint.h>
54 #include <linux/ftrace.h>
55 #include <linux/async.h>
56 #include <linux/percpu.h>
57 #include <linux/kmemleak.h>
58 #include <linux/jump_label.h>
59 #include <linux/pfn.h>
60 #include <linux/bsearch.h>
61
62 #define CREATE_TRACE_POINTS
63 #include <trace/events/module.h>
64
65 #ifndef ARCH_SHF_SMALL
66 #define ARCH_SHF_SMALL 0
67 #endif
68
69 /*
70 * Modules' sections will be aligned on page boundaries
71 * to ensure complete separation of code and data, but
72 * only when CONFIG_DEBUG_SET_MODULE_RONX=y
73 */
74 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
75 # define debug_align(X) ALIGN(X, PAGE_SIZE)
76 #else
77 # define debug_align(X) (X)
78 #endif
79
80 /*
81 * Given BASE and SIZE this macro calculates the number of pages the
82 * memory regions occupies
83 */
84 #define MOD_NUMBER_OF_PAGES(BASE, SIZE) (((SIZE) > 0) ? \
85 (PFN_DOWN((unsigned long)(BASE) + (SIZE) - 1) - \
86 PFN_DOWN((unsigned long)BASE) + 1) \
87 : (0UL))
88
89 /* If this is set, the section belongs in the init part of the module */
90 #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
91
92 /*
93 * Mutex protects:
94 * 1) List of modules (also safely readable with preempt_disable),
95 * 2) module_use links,
96 * 3) module_addr_min/module_addr_max.
97 * (delete uses stop_machine/add uses RCU list operations). */
98 DEFINE_MUTEX(module_mutex);
99 EXPORT_SYMBOL_GPL(module_mutex);
100 static LIST_HEAD(modules);
101 #ifdef CONFIG_KGDB_KDB
102 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
103 #endif /* CONFIG_KGDB_KDB */
104
105
106 /* Block module loading/unloading? */
107 int modules_disabled = 0;
108 core_param(nomodule, modules_disabled, bint, 0);
109
110 /* Waiting for a module to finish initializing? */
111 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
112
113 static BLOCKING_NOTIFIER_HEAD(module_notify_list);
114
115 /* Bounds of module allocation, for speeding __module_address.
116 * Protected by module_mutex. */
117 static unsigned long module_addr_min = -1UL, module_addr_max = 0;
118
119 int register_module_notifier(struct notifier_block * nb)
120 {
121 return blocking_notifier_chain_register(&module_notify_list, nb);
122 }
123 EXPORT_SYMBOL(register_module_notifier);
124
125 int unregister_module_notifier(struct notifier_block * nb)
126 {
127 return blocking_notifier_chain_unregister(&module_notify_list, nb);
128 }
129 EXPORT_SYMBOL(unregister_module_notifier);
130
131 struct load_info {
132 Elf_Ehdr *hdr;
133 unsigned long len;
134 Elf_Shdr *sechdrs;
135 char *secstrings, *strtab;
136 unsigned long symoffs, stroffs;
137 struct _ddebug *debug;
138 unsigned int num_debug;
139 struct {
140 unsigned int sym, str, mod, vers, info, pcpu;
141 } index;
142 };
143
144 /* We require a truly strong try_module_get(): 0 means failure due to
145 ongoing or failed initialization etc. */
146 static inline int strong_try_module_get(struct module *mod)
147 {
148 if (mod && mod->state == MODULE_STATE_COMING)
149 return -EBUSY;
150 if (try_module_get(mod))
151 return 0;
152 else
153 return -ENOENT;
154 }
155
156 static inline void add_taint_module(struct module *mod, unsigned flag)
157 {
158 add_taint(flag);
159 mod->taints |= (1U << flag);
160 }
161
162 /*
163 * A thread that wants to hold a reference to a module only while it
164 * is running can call this to safely exit. nfsd and lockd use this.
165 */
166 void __module_put_and_exit(struct module *mod, long code)
167 {
168 module_put(mod);
169 do_exit(code);
170 }
171 EXPORT_SYMBOL(__module_put_and_exit);
172
173 /* Find a module section: 0 means not found. */
174 static unsigned int find_sec(const struct load_info *info, const char *name)
175 {
176 unsigned int i;
177
178 for (i = 1; i < info->hdr->e_shnum; i++) {
179 Elf_Shdr *shdr = &info->sechdrs[i];
180 /* Alloc bit cleared means "ignore it." */
181 if ((shdr->sh_flags & SHF_ALLOC)
182 && strcmp(info->secstrings + shdr->sh_name, name) == 0)
183 return i;
184 }
185 return 0;
186 }
187
188 /* Find a module section, or NULL. */
189 static void *section_addr(const struct load_info *info, const char *name)
190 {
191 /* Section 0 has sh_addr 0. */
192 return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
193 }
194
195 /* Find a module section, or NULL. Fill in number of "objects" in section. */
196 static void *section_objs(const struct load_info *info,
197 const char *name,
198 size_t object_size,
199 unsigned int *num)
200 {
201 unsigned int sec = find_sec(info, name);
202
203 /* Section 0 has sh_addr 0 and sh_size 0. */
204 *num = info->sechdrs[sec].sh_size / object_size;
205 return (void *)info->sechdrs[sec].sh_addr;
206 }
207
208 /* Provided by the linker */
209 extern const struct kernel_symbol __start___ksymtab[];
210 extern const struct kernel_symbol __stop___ksymtab[];
211 extern const struct kernel_symbol __start___ksymtab_gpl[];
212 extern const struct kernel_symbol __stop___ksymtab_gpl[];
213 extern const struct kernel_symbol __start___ksymtab_gpl_future[];
214 extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
215 extern const unsigned long __start___kcrctab[];
216 extern const unsigned long __start___kcrctab_gpl[];
217 extern const unsigned long __start___kcrctab_gpl_future[];
218 #ifdef CONFIG_UNUSED_SYMBOLS
219 extern const struct kernel_symbol __start___ksymtab_unused[];
220 extern const struct kernel_symbol __stop___ksymtab_unused[];
221 extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
222 extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
223 extern const unsigned long __start___kcrctab_unused[];
224 extern const unsigned long __start___kcrctab_unused_gpl[];
225 #endif
226
227 #ifndef CONFIG_MODVERSIONS
228 #define symversion(base, idx) NULL
229 #else
230 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
231 #endif
232
233 static bool each_symbol_in_section(const struct symsearch *arr,
234 unsigned int arrsize,
235 struct module *owner,
236 bool (*fn)(const struct symsearch *syms,
237 struct module *owner,
238 void *data),
239 void *data)
240 {
241 unsigned int j;
242
243 for (j = 0; j < arrsize; j++) {
244 if (fn(&arr[j], owner, data))
245 return true;
246 }
247
248 return false;
249 }
250
251 /* Returns true as soon as fn returns true, otherwise false. */
252 bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
253 struct module *owner,
254 void *data),
255 void *data)
256 {
257 struct module *mod;
258 static const struct symsearch arr[] = {
259 { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
260 NOT_GPL_ONLY, false },
261 { __start___ksymtab_gpl, __stop___ksymtab_gpl,
262 __start___kcrctab_gpl,
263 GPL_ONLY, false },
264 { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
265 __start___kcrctab_gpl_future,
266 WILL_BE_GPL_ONLY, false },
267 #ifdef CONFIG_UNUSED_SYMBOLS
268 { __start___ksymtab_unused, __stop___ksymtab_unused,
269 __start___kcrctab_unused,
270 NOT_GPL_ONLY, true },
271 { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
272 __start___kcrctab_unused_gpl,
273 GPL_ONLY, true },
274 #endif
275 };
276
277 if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
278 return true;
279
280 list_for_each_entry_rcu(mod, &modules, list) {
281 struct symsearch arr[] = {
282 { mod->syms, mod->syms + mod->num_syms, mod->crcs,
283 NOT_GPL_ONLY, false },
284 { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
285 mod->gpl_crcs,
286 GPL_ONLY, false },
287 { mod->gpl_future_syms,
288 mod->gpl_future_syms + mod->num_gpl_future_syms,
289 mod->gpl_future_crcs,
290 WILL_BE_GPL_ONLY, false },
291 #ifdef CONFIG_UNUSED_SYMBOLS
292 { mod->unused_syms,
293 mod->unused_syms + mod->num_unused_syms,
294 mod->unused_crcs,
295 NOT_GPL_ONLY, true },
296 { mod->unused_gpl_syms,
297 mod->unused_gpl_syms + mod->num_unused_gpl_syms,
298 mod->unused_gpl_crcs,
299 GPL_ONLY, true },
300 #endif
301 };
302
303 if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
304 return true;
305 }
306 return false;
307 }
308 EXPORT_SYMBOL_GPL(each_symbol_section);
309
310 struct find_symbol_arg {
311 /* Input */
312 const char *name;
313 bool gplok;
314 bool warn;
315
316 /* Output */
317 struct module *owner;
318 const unsigned long *crc;
319 const struct kernel_symbol *sym;
320 };
321
322 static bool check_symbol(const struct symsearch *syms,
323 struct module *owner,
324 unsigned int symnum, void *data)
325 {
326 struct find_symbol_arg *fsa = data;
327
328 if (!fsa->gplok) {
329 if (syms->licence == GPL_ONLY)
330 return false;
331 if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
332 printk(KERN_WARNING "Symbol %s is being used "
333 "by a non-GPL module, which will not "
334 "be allowed in the future\n", fsa->name);
335 printk(KERN_WARNING "Please see the file "
336 "Documentation/feature-removal-schedule.txt "
337 "in the kernel source tree for more details.\n");
338 }
339 }
340
341 #ifdef CONFIG_UNUSED_SYMBOLS
342 if (syms->unused && fsa->warn) {
343 printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
344 "however this module is using it.\n", fsa->name);
345 printk(KERN_WARNING
346 "This symbol will go away in the future.\n");
347 printk(KERN_WARNING
348 "Please evalute if this is the right api to use and if "
349 "it really is, submit a report the linux kernel "
350 "mailinglist together with submitting your code for "
351 "inclusion.\n");
352 }
353 #endif
354
355 fsa->owner = owner;
356 fsa->crc = symversion(syms->crcs, symnum);
357 fsa->sym = &syms->start[symnum];
358 return true;
359 }
360
361 static int cmp_name(const void *va, const void *vb)
362 {
363 const char *a;
364 const struct kernel_symbol *b;
365 a = va; b = vb;
366 return strcmp(a, b->name);
367 }
368
369 static bool find_symbol_in_section(const struct symsearch *syms,
370 struct module *owner,
371 void *data)
372 {
373 struct find_symbol_arg *fsa = data;
374 struct kernel_symbol *sym;
375
376 sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
377 sizeof(struct kernel_symbol), cmp_name);
378
379 if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
380 return true;
381
382 return false;
383 }
384
385 /* Find a symbol and return it, along with, (optional) crc and
386 * (optional) module which owns it. Needs preempt disabled or module_mutex. */
387 const struct kernel_symbol *find_symbol(const char *name,
388 struct module **owner,
389 const unsigned long **crc,
390 bool gplok,
391 bool warn)
392 {
393 struct find_symbol_arg fsa;
394
395 fsa.name = name;
396 fsa.gplok = gplok;
397 fsa.warn = warn;
398
399 if (each_symbol_section(find_symbol_in_section, &fsa)) {
400 if (owner)
401 *owner = fsa.owner;
402 if (crc)
403 *crc = fsa.crc;
404 return fsa.sym;
405 }
406
407 pr_debug("Failed to find symbol %s\n", name);
408 return NULL;
409 }
410 EXPORT_SYMBOL_GPL(find_symbol);
411
412 /* Search for module by name: must hold module_mutex. */
413 struct module *find_module(const char *name)
414 {
415 struct module *mod;
416
417 list_for_each_entry(mod, &modules, list) {
418 if (strcmp(mod->name, name) == 0)
419 return mod;
420 }
421 return NULL;
422 }
423 EXPORT_SYMBOL_GPL(find_module);
424
425 #ifdef CONFIG_SMP
426
427 static inline void __percpu *mod_percpu(struct module *mod)
428 {
429 return mod->percpu;
430 }
431
432 static int percpu_modalloc(struct module *mod,
433 unsigned long size, unsigned long align)
434 {
435 if (align > PAGE_SIZE) {
436 printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
437 mod->name, align, PAGE_SIZE);
438 align = PAGE_SIZE;
439 }
440
441 mod->percpu = __alloc_reserved_percpu(size, align);
442 if (!mod->percpu) {
443 printk(KERN_WARNING
444 "%s: Could not allocate %lu bytes percpu data\n",
445 mod->name, size);
446 return -ENOMEM;
447 }
448 mod->percpu_size = size;
449 return 0;
450 }
451
452 static void percpu_modfree(struct module *mod)
453 {
454 free_percpu(mod->percpu);
455 }
456
457 static unsigned int find_pcpusec(struct load_info *info)
458 {
459 return find_sec(info, ".data..percpu");
460 }
461
462 static void percpu_modcopy(struct module *mod,
463 const void *from, unsigned long size)
464 {
465 int cpu;
466
467 for_each_possible_cpu(cpu)
468 memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
469 }
470
471 /**
472 * is_module_percpu_address - test whether address is from module static percpu
473 * @addr: address to test
474 *
475 * Test whether @addr belongs to module static percpu area.
476 *
477 * RETURNS:
478 * %true if @addr is from module static percpu area
479 */
480 bool is_module_percpu_address(unsigned long addr)
481 {
482 struct module *mod;
483 unsigned int cpu;
484
485 preempt_disable();
486
487 list_for_each_entry_rcu(mod, &modules, list) {
488 if (!mod->percpu_size)
489 continue;
490 for_each_possible_cpu(cpu) {
491 void *start = per_cpu_ptr(mod->percpu, cpu);
492
493 if ((void *)addr >= start &&
494 (void *)addr < start + mod->percpu_size) {
495 preempt_enable();
496 return true;
497 }
498 }
499 }
500
501 preempt_enable();
502 return false;
503 }
504
505 #else /* ... !CONFIG_SMP */
506
507 static inline void __percpu *mod_percpu(struct module *mod)
508 {
509 return NULL;
510 }
511 static inline int percpu_modalloc(struct module *mod,
512 unsigned long size, unsigned long align)
513 {
514 return -ENOMEM;
515 }
516 static inline void percpu_modfree(struct module *mod)
517 {
518 }
519 static unsigned int find_pcpusec(struct load_info *info)
520 {
521 return 0;
522 }
523 static inline void percpu_modcopy(struct module *mod,
524 const void *from, unsigned long size)
525 {
526 /* pcpusec should be 0, and size of that section should be 0. */
527 BUG_ON(size != 0);
528 }
529 bool is_module_percpu_address(unsigned long addr)
530 {
531 return false;
532 }
533
534 #endif /* CONFIG_SMP */
535
536 #define MODINFO_ATTR(field) \
537 static void setup_modinfo_##field(struct module *mod, const char *s) \
538 { \
539 mod->field = kstrdup(s, GFP_KERNEL); \
540 } \
541 static ssize_t show_modinfo_##field(struct module_attribute *mattr, \
542 struct module_kobject *mk, char *buffer) \
543 { \
544 return sprintf(buffer, "%s\n", mk->mod->field); \
545 } \
546 static int modinfo_##field##_exists(struct module *mod) \
547 { \
548 return mod->field != NULL; \
549 } \
550 static void free_modinfo_##field(struct module *mod) \
551 { \
552 kfree(mod->field); \
553 mod->field = NULL; \
554 } \
555 static struct module_attribute modinfo_##field = { \
556 .attr = { .name = __stringify(field), .mode = 0444 }, \
557 .show = show_modinfo_##field, \
558 .setup = setup_modinfo_##field, \
559 .test = modinfo_##field##_exists, \
560 .free = free_modinfo_##field, \
561 };
562
563 MODINFO_ATTR(version);
564 MODINFO_ATTR(srcversion);
565
566 static char last_unloaded_module[MODULE_NAME_LEN+1];
567
568 #ifdef CONFIG_MODULE_UNLOAD
569
570 EXPORT_TRACEPOINT_SYMBOL(module_get);
571
572 /* Init the unload section of the module. */
573 static int module_unload_init(struct module *mod)
574 {
575 mod->refptr = alloc_percpu(struct module_ref);
576 if (!mod->refptr)
577 return -ENOMEM;
578
579 INIT_LIST_HEAD(&mod->source_list);
580 INIT_LIST_HEAD(&mod->target_list);
581
582 /* Hold reference count during initialization. */
583 __this_cpu_write(mod->refptr->incs, 1);
584 /* Backwards compatibility macros put refcount during init. */
585 mod->waiter = current;
586
587 return 0;
588 }
589
590 /* Does a already use b? */
591 static int already_uses(struct module *a, struct module *b)
592 {
593 struct module_use *use;
594
595 list_for_each_entry(use, &b->source_list, source_list) {
596 if (use->source == a) {
597 pr_debug("%s uses %s!\n", a->name, b->name);
598 return 1;
599 }
600 }
601 pr_debug("%s does not use %s!\n", a->name, b->name);
602 return 0;
603 }
604
605 /*
606 * Module a uses b
607 * - we add 'a' as a "source", 'b' as a "target" of module use
608 * - the module_use is added to the list of 'b' sources (so
609 * 'b' can walk the list to see who sourced them), and of 'a'
610 * targets (so 'a' can see what modules it targets).
611 */
612 static int add_module_usage(struct module *a, struct module *b)
613 {
614 struct module_use *use;
615
616 pr_debug("Allocating new usage for %s.\n", a->name);
617 use = kmalloc(sizeof(*use), GFP_ATOMIC);
618 if (!use) {
619 printk(KERN_WARNING "%s: out of memory loading\n", a->name);
620 return -ENOMEM;
621 }
622
623 use->source = a;
624 use->target = b;
625 list_add(&use->source_list, &b->source_list);
626 list_add(&use->target_list, &a->target_list);
627 return 0;
628 }
629
630 /* Module a uses b: caller needs module_mutex() */
631 int ref_module(struct module *a, struct module *b)
632 {
633 int err;
634
635 if (b == NULL || already_uses(a, b))
636 return 0;
637
638 /* If module isn't available, we fail. */
639 err = strong_try_module_get(b);
640 if (err)
641 return err;
642
643 err = add_module_usage(a, b);
644 if (err) {
645 module_put(b);
646 return err;
647 }
648 return 0;
649 }
650 EXPORT_SYMBOL_GPL(ref_module);
651
652 /* Clear the unload stuff of the module. */
653 static void module_unload_free(struct module *mod)
654 {
655 struct module_use *use, *tmp;
656
657 mutex_lock(&module_mutex);
658 list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
659 struct module *i = use->target;
660 pr_debug("%s unusing %s\n", mod->name, i->name);
661 module_put(i);
662 list_del(&use->source_list);
663 list_del(&use->target_list);
664 kfree(use);
665 }
666 mutex_unlock(&module_mutex);
667
668 free_percpu(mod->refptr);
669 }
670
671 #ifdef CONFIG_MODULE_FORCE_UNLOAD
672 static inline int try_force_unload(unsigned int flags)
673 {
674 int ret = (flags & O_TRUNC);
675 if (ret)
676 add_taint(TAINT_FORCED_RMMOD);
677 return ret;
678 }
679 #else
680 static inline int try_force_unload(unsigned int flags)
681 {
682 return 0;
683 }
684 #endif /* CONFIG_MODULE_FORCE_UNLOAD */
685
686 struct stopref
687 {
688 struct module *mod;
689 int flags;
690 int *forced;
691 };
692
693 /* Whole machine is stopped with interrupts off when this runs. */
694 static int __try_stop_module(void *_sref)
695 {
696 struct stopref *sref = _sref;
697
698 /* If it's not unused, quit unless we're forcing. */
699 if (module_refcount(sref->mod) != 0) {
700 if (!(*sref->forced = try_force_unload(sref->flags)))
701 return -EWOULDBLOCK;
702 }
703
704 /* Mark it as dying. */
705 sref->mod->state = MODULE_STATE_GOING;
706 return 0;
707 }
708
709 static int try_stop_module(struct module *mod, int flags, int *forced)
710 {
711 if (flags & O_NONBLOCK) {
712 struct stopref sref = { mod, flags, forced };
713
714 return stop_machine(__try_stop_module, &sref, NULL);
715 } else {
716 /* We don't need to stop the machine for this. */
717 mod->state = MODULE_STATE_GOING;
718 synchronize_sched();
719 return 0;
720 }
721 }
722
723 unsigned long module_refcount(struct module *mod)
724 {
725 unsigned long incs = 0, decs = 0;
726 int cpu;
727
728 for_each_possible_cpu(cpu)
729 decs += per_cpu_ptr(mod->refptr, cpu)->decs;
730 /*
731 * ensure the incs are added up after the decs.
732 * module_put ensures incs are visible before decs with smp_wmb.
733 *
734 * This 2-count scheme avoids the situation where the refcount
735 * for CPU0 is read, then CPU0 increments the module refcount,
736 * then CPU1 drops that refcount, then the refcount for CPU1 is
737 * read. We would record a decrement but not its corresponding
738 * increment so we would see a low count (disaster).
739 *
740 * Rare situation? But module_refcount can be preempted, and we
741 * might be tallying up 4096+ CPUs. So it is not impossible.
742 */
743 smp_rmb();
744 for_each_possible_cpu(cpu)
745 incs += per_cpu_ptr(mod->refptr, cpu)->incs;
746 return incs - decs;
747 }
748 EXPORT_SYMBOL(module_refcount);
749
750 /* This exists whether we can unload or not */
751 static void free_module(struct module *mod);
752
753 static void wait_for_zero_refcount(struct module *mod)
754 {
755 /* Since we might sleep for some time, release the mutex first */
756 mutex_unlock(&module_mutex);
757 for (;;) {
758 pr_debug("Looking at refcount...\n");
759 set_current_state(TASK_UNINTERRUPTIBLE);
760 if (module_refcount(mod) == 0)
761 break;
762 schedule();
763 }
764 current->state = TASK_RUNNING;
765 mutex_lock(&module_mutex);
766 }
767
768 SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
769 unsigned int, flags)
770 {
771 struct module *mod;
772 char name[MODULE_NAME_LEN];
773 int ret, forced = 0;
774
775 if (!capable(CAP_SYS_MODULE) || modules_disabled)
776 return -EPERM;
777
778 if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
779 return -EFAULT;
780 name[MODULE_NAME_LEN-1] = '\0';
781
782 if (mutex_lock_interruptible(&module_mutex) != 0)
783 return -EINTR;
784
785 mod = find_module(name);
786 if (!mod) {
787 ret = -ENOENT;
788 goto out;
789 }
790
791 if (!list_empty(&mod->source_list)) {
792 /* Other modules depend on us: get rid of them first. */
793 ret = -EWOULDBLOCK;
794 goto out;
795 }
796
797 /* Doing init or already dying? */
798 if (mod->state != MODULE_STATE_LIVE) {
799 /* FIXME: if (force), slam module count and wake up
800 waiter --RR */
801 pr_debug("%s already dying\n", mod->name);
802 ret = -EBUSY;
803 goto out;
804 }
805
806 /* If it has an init func, it must have an exit func to unload */
807 if (mod->init && !mod->exit) {
808 forced = try_force_unload(flags);
809 if (!forced) {
810 /* This module can't be removed */
811 ret = -EBUSY;
812 goto out;
813 }
814 }
815
816 /* Set this up before setting mod->state */
817 mod->waiter = current;
818
819 /* Stop the machine so refcounts can't move and disable module. */
820 ret = try_stop_module(mod, flags, &forced);
821 if (ret != 0)
822 goto out;
823
824 /* Never wait if forced. */
825 if (!forced && module_refcount(mod) != 0)
826 wait_for_zero_refcount(mod);
827
828 mutex_unlock(&module_mutex);
829 /* Final destruction now no one is using it. */
830 if (mod->exit != NULL)
831 mod->exit();
832 blocking_notifier_call_chain(&module_notify_list,
833 MODULE_STATE_GOING, mod);
834 async_synchronize_full();
835
836 /* Store the name of the last unloaded module for diagnostic purposes */
837 strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
838
839 free_module(mod);
840 return 0;
841 out:
842 mutex_unlock(&module_mutex);
843 return ret;
844 }
845
846 static inline void print_unload_info(struct seq_file *m, struct module *mod)
847 {
848 struct module_use *use;
849 int printed_something = 0;
850
851 seq_printf(m, " %lu ", module_refcount(mod));
852
853 /* Always include a trailing , so userspace can differentiate
854 between this and the old multi-field proc format. */
855 list_for_each_entry(use, &mod->source_list, source_list) {
856 printed_something = 1;
857 seq_printf(m, "%s,", use->source->name);
858 }
859
860 if (mod->init != NULL && mod->exit == NULL) {
861 printed_something = 1;
862 seq_printf(m, "[permanent],");
863 }
864
865 if (!printed_something)
866 seq_printf(m, "-");
867 }
868
869 void __symbol_put(const char *symbol)
870 {
871 struct module *owner;
872
873 preempt_disable();
874 if (!find_symbol(symbol, &owner, NULL, true, false))
875 BUG();
876 module_put(owner);
877 preempt_enable();
878 }
879 EXPORT_SYMBOL(__symbol_put);
880
881 /* Note this assumes addr is a function, which it currently always is. */
882 void symbol_put_addr(void *addr)
883 {
884 struct module *modaddr;
885 unsigned long a = (unsigned long)dereference_function_descriptor(addr);
886
887 if (core_kernel_text(a))
888 return;
889
890 /* module_text_address is safe here: we're supposed to have reference
891 * to module from symbol_get, so it can't go away. */
892 modaddr = __module_text_address(a);
893 BUG_ON(!modaddr);
894 module_put(modaddr);
895 }
896 EXPORT_SYMBOL_GPL(symbol_put_addr);
897
898 static ssize_t show_refcnt(struct module_attribute *mattr,
899 struct module_kobject *mk, char *buffer)
900 {
901 return sprintf(buffer, "%lu\n", module_refcount(mk->mod));
902 }
903
904 static struct module_attribute modinfo_refcnt =
905 __ATTR(refcnt, 0444, show_refcnt, NULL);
906
907 void __module_get(struct module *module)
908 {
909 if (module) {
910 preempt_disable();
911 __this_cpu_inc(module->refptr->incs);
912 trace_module_get(module, _RET_IP_);
913 preempt_enable();
914 }
915 }
916 EXPORT_SYMBOL(__module_get);
917
918 bool try_module_get(struct module *module)
919 {
920 bool ret = true;
921
922 if (module) {
923 preempt_disable();
924
925 if (likely(module_is_live(module))) {
926 __this_cpu_inc(module->refptr->incs);
927 trace_module_get(module, _RET_IP_);
928 } else
929 ret = false;
930
931 preempt_enable();
932 }
933 return ret;
934 }
935 EXPORT_SYMBOL(try_module_get);
936
937 void module_put(struct module *module)
938 {
939 if (module) {
940 preempt_disable();
941 smp_wmb(); /* see comment in module_refcount */
942 __this_cpu_inc(module->refptr->decs);
943
944 trace_module_put(module, _RET_IP_);
945 /* Maybe they're waiting for us to drop reference? */
946 if (unlikely(!module_is_live(module)))
947 wake_up_process(module->waiter);
948 preempt_enable();
949 }
950 }
951 EXPORT_SYMBOL(module_put);
952
953 #else /* !CONFIG_MODULE_UNLOAD */
954 static inline void print_unload_info(struct seq_file *m, struct module *mod)
955 {
956 /* We don't know the usage count, or what modules are using. */
957 seq_printf(m, " - -");
958 }
959
960 static inline void module_unload_free(struct module *mod)
961 {
962 }
963
964 int ref_module(struct module *a, struct module *b)
965 {
966 return strong_try_module_get(b);
967 }
968 EXPORT_SYMBOL_GPL(ref_module);
969
970 static inline int module_unload_init(struct module *mod)
971 {
972 return 0;
973 }
974 #endif /* CONFIG_MODULE_UNLOAD */
975
976 static size_t module_flags_taint(struct module *mod, char *buf)
977 {
978 size_t l = 0;
979
980 if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
981 buf[l++] = 'P';
982 if (mod->taints & (1 << TAINT_OOT_MODULE))
983 buf[l++] = 'O';
984 if (mod->taints & (1 << TAINT_FORCED_MODULE))
985 buf[l++] = 'F';
986 if (mod->taints & (1 << TAINT_CRAP))
987 buf[l++] = 'C';
988 /*
989 * TAINT_FORCED_RMMOD: could be added.
990 * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
991 * apply to modules.
992 */
993 return l;
994 }
995
996 static ssize_t show_initstate(struct module_attribute *mattr,
997 struct module_kobject *mk, char *buffer)
998 {
999 const char *state = "unknown";
1000
1001 switch (mk->mod->state) {
1002 case MODULE_STATE_LIVE:
1003 state = "live";
1004 break;
1005 case MODULE_STATE_COMING:
1006 state = "coming";
1007 break;
1008 case MODULE_STATE_GOING:
1009 state = "going";
1010 break;
1011 }
1012 return sprintf(buffer, "%s\n", state);
1013 }
1014
1015 static struct module_attribute modinfo_initstate =
1016 __ATTR(initstate, 0444, show_initstate, NULL);
1017
1018 static ssize_t store_uevent(struct module_attribute *mattr,
1019 struct module_kobject *mk,
1020 const char *buffer, size_t count)
1021 {
1022 enum kobject_action action;
1023
1024 if (kobject_action_type(buffer, count, &action) == 0)
1025 kobject_uevent(&mk->kobj, action);
1026 return count;
1027 }
1028
1029 struct module_attribute module_uevent =
1030 __ATTR(uevent, 0200, NULL, store_uevent);
1031
1032 static ssize_t show_coresize(struct module_attribute *mattr,
1033 struct module_kobject *mk, char *buffer)
1034 {
1035 return sprintf(buffer, "%u\n", mk->mod->core_size);
1036 }
1037
1038 static struct module_attribute modinfo_coresize =
1039 __ATTR(coresize, 0444, show_coresize, NULL);
1040
1041 static ssize_t show_initsize(struct module_attribute *mattr,
1042 struct module_kobject *mk, char *buffer)
1043 {
1044 return sprintf(buffer, "%u\n", mk->mod->init_size);
1045 }
1046
1047 static struct module_attribute modinfo_initsize =
1048 __ATTR(initsize, 0444, show_initsize, NULL);
1049
1050 static ssize_t show_taint(struct module_attribute *mattr,
1051 struct module_kobject *mk, char *buffer)
1052 {
1053 size_t l;
1054
1055 l = module_flags_taint(mk->mod, buffer);
1056 buffer[l++] = '\n';
1057 return l;
1058 }
1059
1060 static struct module_attribute modinfo_taint =
1061 __ATTR(taint, 0444, show_taint, NULL);
1062
1063 static struct module_attribute *modinfo_attrs[] = {
1064 &module_uevent,
1065 &modinfo_version,
1066 &modinfo_srcversion,
1067 &modinfo_initstate,
1068 &modinfo_coresize,
1069 &modinfo_initsize,
1070 &modinfo_taint,
1071 #ifdef CONFIG_MODULE_UNLOAD
1072 &modinfo_refcnt,
1073 #endif
1074 NULL,
1075 };
1076
1077 static const char vermagic[] = VERMAGIC_STRING;
1078
1079 static int try_to_force_load(struct module *mod, const char *reason)
1080 {
1081 #ifdef CONFIG_MODULE_FORCE_LOAD
1082 if (!test_taint(TAINT_FORCED_MODULE))
1083 printk(KERN_WARNING "%s: %s: kernel tainted.\n",
1084 mod->name, reason);
1085 add_taint_module(mod, TAINT_FORCED_MODULE);
1086 return 0;
1087 #else
1088 return -ENOEXEC;
1089 #endif
1090 }
1091
1092 #ifdef CONFIG_MODVERSIONS
1093 /* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
1094 static unsigned long maybe_relocated(unsigned long crc,
1095 const struct module *crc_owner)
1096 {
1097 #ifdef ARCH_RELOCATES_KCRCTAB
1098 if (crc_owner == NULL)
1099 return crc - (unsigned long)reloc_start;
1100 #endif
1101 return crc;
1102 }
1103
1104 static int check_version(Elf_Shdr *sechdrs,
1105 unsigned int versindex,
1106 const char *symname,
1107 struct module *mod,
1108 const unsigned long *crc,
1109 const struct module *crc_owner)
1110 {
1111 unsigned int i, num_versions;
1112 struct modversion_info *versions;
1113
1114 /* Exporting module didn't supply crcs? OK, we're already tainted. */
1115 if (!crc)
1116 return 1;
1117
1118 /* No versions at all? modprobe --force does this. */
1119 if (versindex == 0)
1120 return try_to_force_load(mod, symname) == 0;
1121
1122 versions = (void *) sechdrs[versindex].sh_addr;
1123 num_versions = sechdrs[versindex].sh_size
1124 / sizeof(struct modversion_info);
1125
1126 for (i = 0; i < num_versions; i++) {
1127 if (strcmp(versions[i].name, symname) != 0)
1128 continue;
1129
1130 if (versions[i].crc == maybe_relocated(*crc, crc_owner))
1131 return 1;
1132 pr_debug("Found checksum %lX vs module %lX\n",
1133 maybe_relocated(*crc, crc_owner), versions[i].crc);
1134 goto bad_version;
1135 }
1136
1137 printk(KERN_WARNING "%s: no symbol version for %s\n",
1138 mod->name, symname);
1139 return 0;
1140
1141 bad_version:
1142 printk("%s: disagrees about version of symbol %s\n",
1143 mod->name, symname);
1144 return 0;
1145 }
1146
1147 static inline int check_modstruct_version(Elf_Shdr *sechdrs,
1148 unsigned int versindex,
1149 struct module *mod)
1150 {
1151 const unsigned long *crc;
1152
1153 /* Since this should be found in kernel (which can't be removed),
1154 * no locking is necessary. */
1155 if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
1156 &crc, true, false))
1157 BUG();
1158 return check_version(sechdrs, versindex, "module_layout", mod, crc,
1159 NULL);
1160 }
1161
1162 /* First part is kernel version, which we ignore if module has crcs. */
1163 static inline int same_magic(const char *amagic, const char *bmagic,
1164 bool has_crcs)
1165 {
1166 if (has_crcs) {
1167 amagic += strcspn(amagic, " ");
1168 bmagic += strcspn(bmagic, " ");
1169 }
1170 return strcmp(amagic, bmagic) == 0;
1171 }
1172 #else
1173 static inline int check_version(Elf_Shdr *sechdrs,
1174 unsigned int versindex,
1175 const char *symname,
1176 struct module *mod,
1177 const unsigned long *crc,
1178 const struct module *crc_owner)
1179 {
1180 return 1;
1181 }
1182
1183 static inline int check_modstruct_version(Elf_Shdr *sechdrs,
1184 unsigned int versindex,
1185 struct module *mod)
1186 {
1187 return 1;
1188 }
1189
1190 static inline int same_magic(const char *amagic, const char *bmagic,
1191 bool has_crcs)
1192 {
1193 return strcmp(amagic, bmagic) == 0;
1194 }
1195 #endif /* CONFIG_MODVERSIONS */
1196
1197 /* Resolve a symbol for this module. I.e. if we find one, record usage. */
1198 static const struct kernel_symbol *resolve_symbol(struct module *mod,
1199 const struct load_info *info,
1200 const char *name,
1201 char ownername[])
1202 {
1203 struct module *owner;
1204 const struct kernel_symbol *sym;
1205 const unsigned long *crc;
1206 int err;
1207
1208 mutex_lock(&module_mutex);
1209 sym = find_symbol(name, &owner, &crc,
1210 !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
1211 if (!sym)
1212 goto unlock;
1213
1214 if (!check_version(info->sechdrs, info->index.vers, name, mod, crc,
1215 owner)) {
1216 sym = ERR_PTR(-EINVAL);
1217 goto getname;
1218 }
1219
1220 err = ref_module(mod, owner);
1221 if (err) {
1222 sym = ERR_PTR(err);
1223 goto getname;
1224 }
1225
1226 getname:
1227 /* We must make copy under the lock if we failed to get ref. */
1228 strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
1229 unlock:
1230 mutex_unlock(&module_mutex);
1231 return sym;
1232 }
1233
1234 static const struct kernel_symbol *
1235 resolve_symbol_wait(struct module *mod,
1236 const struct load_info *info,
1237 const char *name)
1238 {
1239 const struct kernel_symbol *ksym;
1240 char owner[MODULE_NAME_LEN];
1241
1242 if (wait_event_interruptible_timeout(module_wq,
1243 !IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
1244 || PTR_ERR(ksym) != -EBUSY,
1245 30 * HZ) <= 0) {
1246 printk(KERN_WARNING "%s: gave up waiting for init of module %s.\n",
1247 mod->name, owner);
1248 }
1249 return ksym;
1250 }
1251
1252 /*
1253 * /sys/module/foo/sections stuff
1254 * J. Corbet <corbet@lwn.net>
1255 */
1256 #ifdef CONFIG_SYSFS
1257
1258 #ifdef CONFIG_KALLSYMS
1259 static inline bool sect_empty(const Elf_Shdr *sect)
1260 {
1261 return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
1262 }
1263
1264 struct module_sect_attr
1265 {
1266 struct module_attribute mattr;
1267 char *name;
1268 unsigned long address;
1269 };
1270
1271 struct module_sect_attrs
1272 {
1273 struct attribute_group grp;
1274 unsigned int nsections;
1275 struct module_sect_attr attrs[0];
1276 };
1277
1278 static ssize_t module_sect_show(struct module_attribute *mattr,
1279 struct module_kobject *mk, char *buf)
1280 {
1281 struct module_sect_attr *sattr =
1282 container_of(mattr, struct module_sect_attr, mattr);
1283 return sprintf(buf, "0x%pK\n", (void *)sattr->address);
1284 }
1285
1286 static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
1287 {
1288 unsigned int section;
1289
1290 for (section = 0; section < sect_attrs->nsections; section++)
1291 kfree(sect_attrs->attrs[section].name);
1292 kfree(sect_attrs);
1293 }
1294
1295 static void add_sect_attrs(struct module *mod, const struct load_info *info)
1296 {
1297 unsigned int nloaded = 0, i, size[2];
1298 struct module_sect_attrs *sect_attrs;
1299 struct module_sect_attr *sattr;
1300 struct attribute **gattr;
1301
1302 /* Count loaded sections and allocate structures */
1303 for (i = 0; i < info->hdr->e_shnum; i++)
1304 if (!sect_empty(&info->sechdrs[i]))
1305 nloaded++;
1306 size[0] = ALIGN(sizeof(*sect_attrs)
1307 + nloaded * sizeof(sect_attrs->attrs[0]),
1308 sizeof(sect_attrs->grp.attrs[0]));
1309 size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]);
1310 sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
1311 if (sect_attrs == NULL)
1312 return;
1313
1314 /* Setup section attributes. */
1315 sect_attrs->grp.name = "sections";
1316 sect_attrs->grp.attrs = (void *)sect_attrs + size[0];
1317
1318 sect_attrs->nsections = 0;
1319 sattr = &sect_attrs->attrs[0];
1320 gattr = &sect_attrs->grp.attrs[0];
1321 for (i = 0; i < info->hdr->e_shnum; i++) {
1322 Elf_Shdr *sec = &info->sechdrs[i];
1323 if (sect_empty(sec))
1324 continue;
1325 sattr->address = sec->sh_addr;
1326 sattr->name = kstrdup(info->secstrings + sec->sh_name,
1327 GFP_KERNEL);
1328 if (sattr->name == NULL)
1329 goto out;
1330 sect_attrs->nsections++;
1331 sysfs_attr_init(&sattr->mattr.attr);
1332 sattr->mattr.show = module_sect_show;
1333 sattr->mattr.store = NULL;
1334 sattr->mattr.attr.name = sattr->name;
1335 sattr->mattr.attr.mode = S_IRUGO;
1336 *(gattr++) = &(sattr++)->mattr.attr;
1337 }
1338 *gattr = NULL;
1339
1340 if (sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp))
1341 goto out;
1342
1343 mod->sect_attrs = sect_attrs;
1344 return;
1345 out:
1346 free_sect_attrs(sect_attrs);
1347 }
1348
1349 static void remove_sect_attrs(struct module *mod)
1350 {
1351 if (mod->sect_attrs) {
1352 sysfs_remove_group(&mod->mkobj.kobj,
1353 &mod->sect_attrs->grp);
1354 /* We are positive that no one is using any sect attrs
1355 * at this point. Deallocate immediately. */
1356 free_sect_attrs(mod->sect_attrs);
1357 mod->sect_attrs = NULL;
1358 }
1359 }
1360
1361 /*
1362 * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
1363 */
1364
1365 struct module_notes_attrs {
1366 struct kobject *dir;
1367 unsigned int notes;
1368 struct bin_attribute attrs[0];
1369 };
1370
1371 static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
1372 struct bin_attribute *bin_attr,
1373 char *buf, loff_t pos, size_t count)
1374 {
1375 /*
1376 * The caller checked the pos and count against our size.
1377 */
1378 memcpy(buf, bin_attr->private + pos, count);
1379 return count;
1380 }
1381
1382 static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
1383 unsigned int i)
1384 {
1385 if (notes_attrs->dir) {
1386 while (i-- > 0)
1387 sysfs_remove_bin_file(notes_attrs->dir,
1388 &notes_attrs->attrs[i]);
1389 kobject_put(notes_attrs->dir);
1390 }
1391 kfree(notes_attrs);
1392 }
1393
1394 static void add_notes_attrs(struct module *mod, const struct load_info *info)
1395 {
1396 unsigned int notes, loaded, i;
1397 struct module_notes_attrs *notes_attrs;
1398 struct bin_attribute *nattr;
1399
1400 /* failed to create section attributes, so can't create notes */
1401 if (!mod->sect_attrs)
1402 return;
1403
1404 /* Count notes sections and allocate structures. */
1405 notes = 0;
1406 for (i = 0; i < info->hdr->e_shnum; i++)
1407 if (!sect_empty(&info->sechdrs[i]) &&
1408 (info->sechdrs[i].sh_type == SHT_NOTE))
1409 ++notes;
1410
1411 if (notes == 0)
1412 return;
1413
1414 notes_attrs = kzalloc(sizeof(*notes_attrs)
1415 + notes * sizeof(notes_attrs->attrs[0]),
1416 GFP_KERNEL);
1417 if (notes_attrs == NULL)
1418 return;
1419
1420 notes_attrs->notes = notes;
1421 nattr = &notes_attrs->attrs[0];
1422 for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {
1423 if (sect_empty(&info->sechdrs[i]))
1424 continue;
1425 if (info->sechdrs[i].sh_type == SHT_NOTE) {
1426 sysfs_bin_attr_init(nattr);
1427 nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
1428 nattr->attr.mode = S_IRUGO;
1429 nattr->size = info->sechdrs[i].sh_size;
1430 nattr->private = (void *) info->sechdrs[i].sh_addr;
1431 nattr->read = module_notes_read;
1432 ++nattr;
1433 }
1434 ++loaded;
1435 }
1436
1437 notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
1438 if (!notes_attrs->dir)
1439 goto out;
1440
1441 for (i = 0; i < notes; ++i)
1442 if (sysfs_create_bin_file(notes_attrs->dir,
1443 &notes_attrs->attrs[i]))
1444 goto out;
1445
1446 mod->notes_attrs = notes_attrs;
1447 return;
1448
1449 out:
1450 free_notes_attrs(notes_attrs, i);
1451 }
1452
1453 static void remove_notes_attrs(struct module *mod)
1454 {
1455 if (mod->notes_attrs)
1456 free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
1457 }
1458
1459 #else
1460
1461 static inline void add_sect_attrs(struct module *mod,
1462 const struct load_info *info)
1463 {
1464 }
1465
1466 static inline void remove_sect_attrs(struct module *mod)
1467 {
1468 }
1469
1470 static inline void add_notes_attrs(struct module *mod,
1471 const struct load_info *info)
1472 {
1473 }
1474
1475 static inline void remove_notes_attrs(struct module *mod)
1476 {
1477 }
1478 #endif /* CONFIG_KALLSYMS */
1479
1480 static void add_usage_links(struct module *mod)
1481 {
1482 #ifdef CONFIG_MODULE_UNLOAD
1483 struct module_use *use;
1484 int nowarn;
1485
1486 mutex_lock(&module_mutex);
1487 list_for_each_entry(use, &mod->target_list, target_list) {
1488 nowarn = sysfs_create_link(use->target->holders_dir,
1489 &mod->mkobj.kobj, mod->name);
1490 }
1491 mutex_unlock(&module_mutex);
1492 #endif
1493 }
1494
1495 static void del_usage_links(struct module *mod)
1496 {
1497 #ifdef CONFIG_MODULE_UNLOAD
1498 struct module_use *use;
1499
1500 mutex_lock(&module_mutex);
1501 list_for_each_entry(use, &mod->target_list, target_list)
1502 sysfs_remove_link(use->target->holders_dir, mod->name);
1503 mutex_unlock(&module_mutex);
1504 #endif
1505 }
1506
1507 static int module_add_modinfo_attrs(struct module *mod)
1508 {
1509 struct module_attribute *attr;
1510 struct module_attribute *temp_attr;
1511 int error = 0;
1512 int i;
1513
1514 mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
1515 (ARRAY_SIZE(modinfo_attrs) + 1)),
1516 GFP_KERNEL);
1517 if (!mod->modinfo_attrs)
1518 return -ENOMEM;
1519
1520 temp_attr = mod->modinfo_attrs;
1521 for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
1522 if (!attr->test ||
1523 (attr->test && attr->test(mod))) {
1524 memcpy(temp_attr, attr, sizeof(*temp_attr));
1525 sysfs_attr_init(&temp_attr->attr);
1526 error = sysfs_create_file(&mod->mkobj.kobj,&temp_attr->attr);
1527 ++temp_attr;
1528 }
1529 }
1530 return error;
1531 }
1532
1533 static void module_remove_modinfo_attrs(struct module *mod)
1534 {
1535 struct module_attribute *attr;
1536 int i;
1537
1538 for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
1539 /* pick a field to test for end of list */
1540 if (!attr->attr.name)
1541 break;
1542 sysfs_remove_file(&mod->mkobj.kobj,&attr->attr);
1543 if (attr->free)
1544 attr->free(mod);
1545 }
1546 kfree(mod->modinfo_attrs);
1547 }
1548
1549 static int mod_sysfs_init(struct module *mod)
1550 {
1551 int err;
1552 struct kobject *kobj;
1553
1554 if (!module_sysfs_initialized) {
1555 printk(KERN_ERR "%s: module sysfs not initialized\n",
1556 mod->name);
1557 err = -EINVAL;
1558 goto out;
1559 }
1560
1561 kobj = kset_find_obj(module_kset, mod->name);
1562 if (kobj) {
1563 printk(KERN_ERR "%s: module is already loaded\n", mod->name);
1564 kobject_put(kobj);
1565 err = -EINVAL;
1566 goto out;
1567 }
1568
1569 mod->mkobj.mod = mod;
1570
1571 memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
1572 mod->mkobj.kobj.kset = module_kset;
1573 err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
1574 "%s", mod->name);
1575 if (err)
1576 kobject_put(&mod->mkobj.kobj);
1577
1578 /* delay uevent until full sysfs population */
1579 out:
1580 return err;
1581 }
1582
1583 static int mod_sysfs_setup(struct module *mod,
1584 const struct load_info *info,
1585 struct kernel_param *kparam,
1586 unsigned int num_params)
1587 {
1588 int err;
1589
1590 err = mod_sysfs_init(mod);
1591 if (err)
1592 goto out;
1593
1594 mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
1595 if (!mod->holders_dir) {
1596 err = -ENOMEM;
1597 goto out_unreg;
1598 }
1599
1600 err = module_param_sysfs_setup(mod, kparam, num_params);
1601 if (err)
1602 goto out_unreg_holders;
1603
1604 err = module_add_modinfo_attrs(mod);
1605 if (err)
1606 goto out_unreg_param;
1607
1608 add_usage_links(mod);
1609 add_sect_attrs(mod, info);
1610 add_notes_attrs(mod, info);
1611
1612 kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
1613 return 0;
1614
1615 out_unreg_param:
1616 module_param_sysfs_remove(mod);
1617 out_unreg_holders:
1618 kobject_put(mod->holders_dir);
1619 out_unreg:
1620 kobject_put(&mod->mkobj.kobj);
1621 out:
1622 return err;
1623 }
1624
1625 static void mod_sysfs_fini(struct module *mod)
1626 {
1627 remove_notes_attrs(mod);
1628 remove_sect_attrs(mod);
1629 kobject_put(&mod->mkobj.kobj);
1630 }
1631
1632 #else /* !CONFIG_SYSFS */
1633
1634 static int mod_sysfs_setup(struct module *mod,
1635 const struct load_info *info,
1636 struct kernel_param *kparam,
1637 unsigned int num_params)
1638 {
1639 return 0;
1640 }
1641
1642 static void mod_sysfs_fini(struct module *mod)
1643 {
1644 }
1645
1646 static void module_remove_modinfo_attrs(struct module *mod)
1647 {
1648 }
1649
1650 static void del_usage_links(struct module *mod)
1651 {
1652 }
1653
1654 #endif /* CONFIG_SYSFS */
1655
1656 static void mod_sysfs_teardown(struct module *mod)
1657 {
1658 del_usage_links(mod);
1659 module_remove_modinfo_attrs(mod);
1660 module_param_sysfs_remove(mod);
1661 kobject_put(mod->mkobj.drivers_dir);
1662 kobject_put(mod->holders_dir);
1663 mod_sysfs_fini(mod);
1664 }
1665
1666 /*
1667 * unlink the module with the whole machine is stopped with interrupts off
1668 * - this defends against kallsyms not taking locks
1669 */
1670 static int __unlink_module(void *_mod)
1671 {
1672 struct module *mod = _mod;
1673 list_del(&mod->list);
1674 module_bug_cleanup(mod);
1675 return 0;
1676 }
1677
1678 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
1679 /*
1680 * LKM RO/NX protection: protect module's text/ro-data
1681 * from modification and any data from execution.
1682 */
1683 void set_page_attributes(void *start, void *end, int (*set)(unsigned long start, int num_pages))
1684 {
1685 unsigned long begin_pfn = PFN_DOWN((unsigned long)start);
1686 unsigned long end_pfn = PFN_DOWN((unsigned long)end);
1687
1688 if (end_pfn > begin_pfn)
1689 set(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
1690 }
1691
1692 static void set_section_ro_nx(void *base,
1693 unsigned long text_size,
1694 unsigned long ro_size,
1695 unsigned long total_size)
1696 {
1697 /* begin and end PFNs of the current subsection */
1698 unsigned long begin_pfn;
1699 unsigned long end_pfn;
1700
1701 /*
1702 * Set RO for module text and RO-data:
1703 * - Always protect first page.
1704 * - Do not protect last partial page.
1705 */
1706 if (ro_size > 0)
1707 set_page_attributes(base, base + ro_size, set_memory_ro);
1708
1709 /*
1710 * Set NX permissions for module data:
1711 * - Do not protect first partial page.
1712 * - Always protect last page.
1713 */
1714 if (total_size > text_size) {
1715 begin_pfn = PFN_UP((unsigned long)base + text_size);
1716 end_pfn = PFN_UP((unsigned long)base + total_size);
1717 if (end_pfn > begin_pfn)
1718 set_memory_nx(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
1719 }
1720 }
1721
1722 static void unset_module_core_ro_nx(struct module *mod)
1723 {
1724 set_page_attributes(mod->module_core + mod->core_text_size,
1725 mod->module_core + mod->core_size,
1726 set_memory_x);
1727 set_page_attributes(mod->module_core,
1728 mod->module_core + mod->core_ro_size,
1729 set_memory_rw);
1730 }
1731
1732 static void unset_module_init_ro_nx(struct module *mod)
1733 {
1734 set_page_attributes(mod->module_init + mod->init_text_size,
1735 mod->module_init + mod->init_size,
1736 set_memory_x);
1737 set_page_attributes(mod->module_init,
1738 mod->module_init + mod->init_ro_size,
1739 set_memory_rw);
1740 }
1741
1742 /* Iterate through all modules and set each module's text as RW */
1743 void set_all_modules_text_rw(void)
1744 {
1745 struct module *mod;
1746
1747 mutex_lock(&module_mutex);
1748 list_for_each_entry_rcu(mod, &modules, list) {
1749 if ((mod->module_core) && (mod->core_text_size)) {
1750 set_page_attributes(mod->module_core,
1751 mod->module_core + mod->core_text_size,
1752 set_memory_rw);
1753 }
1754 if ((mod->module_init) && (mod->init_text_size)) {
1755 set_page_attributes(mod->module_init,
1756 mod->module_init + mod->init_text_size,
1757 set_memory_rw);
1758 }
1759 }
1760 mutex_unlock(&module_mutex);
1761 }
1762
1763 /* Iterate through all modules and set each module's text as RO */
1764 void set_all_modules_text_ro(void)
1765 {
1766 struct module *mod;
1767
1768 mutex_lock(&module_mutex);
1769 list_for_each_entry_rcu(mod, &modules, list) {
1770 if ((mod->module_core) && (mod->core_text_size)) {
1771 set_page_attributes(mod->module_core,
1772 mod->module_core + mod->core_text_size,
1773 set_memory_ro);
1774 }
1775 if ((mod->module_init) && (mod->init_text_size)) {
1776 set_page_attributes(mod->module_init,
1777 mod->module_init + mod->init_text_size,
1778 set_memory_ro);
1779 }
1780 }
1781 mutex_unlock(&module_mutex);
1782 }
1783 #else
1784 static inline void set_section_ro_nx(void *base, unsigned long text_size, unsigned long ro_size, unsigned long total_size) { }
1785 static void unset_module_core_ro_nx(struct module *mod) { }
1786 static void unset_module_init_ro_nx(struct module *mod) { }
1787 #endif
1788
1789 void __weak module_free(struct module *mod, void *module_region)
1790 {
1791 vfree(module_region);
1792 }
1793
1794 void __weak module_arch_cleanup(struct module *mod)
1795 {
1796 }
1797
1798 /* Free a module, remove from lists, etc. */
1799 static void free_module(struct module *mod)
1800 {
1801 trace_module_free(mod);
1802
1803 /* Delete from various lists */
1804 mutex_lock(&module_mutex);
1805 stop_machine(__unlink_module, mod, NULL);
1806 mutex_unlock(&module_mutex);
1807 mod_sysfs_teardown(mod);
1808
1809 /* Remove dynamic debug info */
1810 ddebug_remove_module(mod->name);
1811
1812 /* Arch-specific cleanup. */
1813 module_arch_cleanup(mod);
1814
1815 /* Module unload stuff */
1816 module_unload_free(mod);
1817
1818 /* Free any allocated parameters. */
1819 destroy_params(mod->kp, mod->num_kp);
1820
1821 /* This may be NULL, but that's OK */
1822 unset_module_init_ro_nx(mod);
1823 module_free(mod, mod->module_init);
1824 kfree(mod->args);
1825 percpu_modfree(mod);
1826
1827 /* Free lock-classes: */
1828 lockdep_free_key_range(mod->module_core, mod->core_size);
1829
1830 /* Finally, free the core (containing the module structure) */
1831 unset_module_core_ro_nx(mod);
1832 module_free(mod, mod->module_core);
1833
1834 #ifdef CONFIG_MPU
1835 update_protections(current->mm);
1836 #endif
1837 }
1838
1839 void *__symbol_get(const char *symbol)
1840 {
1841 struct module *owner;
1842 const struct kernel_symbol *sym;
1843
1844 preempt_disable();
1845 sym = find_symbol(symbol, &owner, NULL, true, true);
1846 if (sym && strong_try_module_get(owner))
1847 sym = NULL;
1848 preempt_enable();
1849
1850 return sym ? (void *)sym->value : NULL;
1851 }
1852 EXPORT_SYMBOL_GPL(__symbol_get);
1853
1854 /*
1855 * Ensure that an exported symbol [global namespace] does not already exist
1856 * in the kernel or in some other module's exported symbol table.
1857 *
1858 * You must hold the module_mutex.
1859 */
1860 static int verify_export_symbols(struct module *mod)
1861 {
1862 unsigned int i;
1863 struct module *owner;
1864 const struct kernel_symbol *s;
1865 struct {
1866 const struct kernel_symbol *sym;
1867 unsigned int num;
1868 } arr[] = {
1869 { mod->syms, mod->num_syms },
1870 { mod->gpl_syms, mod->num_gpl_syms },
1871 { mod->gpl_future_syms, mod->num_gpl_future_syms },
1872 #ifdef CONFIG_UNUSED_SYMBOLS
1873 { mod->unused_syms, mod->num_unused_syms },
1874 { mod->unused_gpl_syms, mod->num_unused_gpl_syms },
1875 #endif
1876 };
1877
1878 for (i = 0; i < ARRAY_SIZE(arr); i++) {
1879 for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
1880 if (find_symbol(s->name, &owner, NULL, true, false)) {
1881 printk(KERN_ERR
1882 "%s: exports duplicate symbol %s"
1883 " (owned by %s)\n",
1884 mod->name, s->name, module_name(owner));
1885 return -ENOEXEC;
1886 }
1887 }
1888 }
1889 return 0;
1890 }
1891
1892 /* Change all symbols so that st_value encodes the pointer directly. */
1893 static int simplify_symbols(struct module *mod, const struct load_info *info)
1894 {
1895 Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
1896 Elf_Sym *sym = (void *)symsec->sh_addr;
1897 unsigned long secbase;
1898 unsigned int i;
1899 int ret = 0;
1900 const struct kernel_symbol *ksym;
1901
1902 for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
1903 const char *name = info->strtab + sym[i].st_name;
1904
1905 switch (sym[i].st_shndx) {
1906 case SHN_COMMON:
1907 /* We compiled with -fno-common. These are not
1908 supposed to happen. */
1909 pr_debug("Common symbol: %s\n", name);
1910 printk("%s: please compile with -fno-common\n",
1911 mod->name);
1912 ret = -ENOEXEC;
1913 break;
1914
1915 case SHN_ABS:
1916 /* Don't need to do anything */
1917 pr_debug("Absolute symbol: 0x%08lx\n",
1918 (long)sym[i].st_value);
1919 break;
1920
1921 case SHN_UNDEF:
1922 ksym = resolve_symbol_wait(mod, info, name);
1923 /* Ok if resolved. */
1924 if (ksym && !IS_ERR(ksym)) {
1925 sym[i].st_value = ksym->value;
1926 break;
1927 }
1928
1929 /* Ok if weak. */
1930 if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
1931 break;
1932
1933 printk(KERN_WARNING "%s: Unknown symbol %s (err %li)\n",
1934 mod->name, name, PTR_ERR(ksym));
1935 ret = PTR_ERR(ksym) ?: -ENOENT;
1936 break;
1937
1938 default:
1939 /* Divert to percpu allocation if a percpu var. */
1940 if (sym[i].st_shndx == info->index.pcpu)
1941 secbase = (unsigned long)mod_percpu(mod);
1942 else
1943 secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
1944 sym[i].st_value += secbase;
1945 break;
1946 }
1947 }
1948
1949 return ret;
1950 }
1951
1952 int __weak apply_relocate(Elf_Shdr *sechdrs,
1953 const char *strtab,
1954 unsigned int symindex,
1955 unsigned int relsec,
1956 struct module *me)
1957 {
1958 pr_err("module %s: REL relocation unsupported\n", me->name);
1959 return -ENOEXEC;
1960 }
1961
1962 int __weak apply_relocate_add(Elf_Shdr *sechdrs,
1963 const char *strtab,
1964 unsigned int symindex,
1965 unsigned int relsec,
1966 struct module *me)
1967 {
1968 pr_err("module %s: RELA relocation unsupported\n", me->name);
1969 return -ENOEXEC;
1970 }
1971
1972 static int apply_relocations(struct module *mod, const struct load_info *info)
1973 {
1974 unsigned int i;
1975 int err = 0;
1976
1977 /* Now do relocations. */
1978 for (i = 1; i < info->hdr->e_shnum; i++) {
1979 unsigned int infosec = info->sechdrs[i].sh_info;
1980
1981 /* Not a valid relocation section? */
1982 if (infosec >= info->hdr->e_shnum)
1983 continue;
1984
1985 /* Don't bother with non-allocated sections */
1986 if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
1987 continue;
1988
1989 if (info->sechdrs[i].sh_type == SHT_REL)
1990 err = apply_relocate(info->sechdrs, info->strtab,
1991 info->index.sym, i, mod);
1992 else if (info->sechdrs[i].sh_type == SHT_RELA)
1993 err = apply_relocate_add(info->sechdrs, info->strtab,
1994 info->index.sym, i, mod);
1995 if (err < 0)
1996 break;
1997 }
1998 return err;
1999 }
2000
2001 /* Additional bytes needed by arch in front of individual sections */
2002 unsigned int __weak arch_mod_section_prepend(struct module *mod,
2003 unsigned int section)
2004 {
2005 /* default implementation just returns zero */
2006 return 0;
2007 }
2008
2009 /* Update size with this section: return offset. */
2010 static long get_offset(struct module *mod, unsigned int *size,
2011 Elf_Shdr *sechdr, unsigned int section)
2012 {
2013 long ret;
2014
2015 *size += arch_mod_section_prepend(mod, section);
2016 ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
2017 *size = ret + sechdr->sh_size;
2018 return ret;
2019 }
2020
2021 /* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
2022 might -- code, read-only data, read-write data, small data. Tally
2023 sizes, and place the offsets into sh_entsize fields: high bit means it
2024 belongs in init. */
2025 static void layout_sections(struct module *mod, struct load_info *info)
2026 {
2027 static unsigned long const masks[][2] = {
2028 /* NOTE: all executable code must be the first section
2029 * in this array; otherwise modify the text_size
2030 * finder in the two loops below */
2031 { SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
2032 { SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
2033 { SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
2034 { ARCH_SHF_SMALL | SHF_ALLOC, 0 }
2035 };
2036 unsigned int m, i;
2037
2038 for (i = 0; i < info->hdr->e_shnum; i++)
2039 info->sechdrs[i].sh_entsize = ~0UL;
2040
2041 pr_debug("Core section allocation order:\n");
2042 for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2043 for (i = 0; i < info->hdr->e_shnum; ++i) {
2044 Elf_Shdr *s = &info->sechdrs[i];
2045 const char *sname = info->secstrings + s->sh_name;
2046
2047 if ((s->sh_flags & masks[m][0]) != masks[m][0]
2048 || (s->sh_flags & masks[m][1])
2049 || s->sh_entsize != ~0UL
2050 || strstarts(sname, ".init"))
2051 continue;
2052 s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
2053 pr_debug("\t%s\n", sname);
2054 }
2055 switch (m) {
2056 case 0: /* executable */
2057 mod->core_size = debug_align(mod->core_size);
2058 mod->core_text_size = mod->core_size;
2059 break;
2060 case 1: /* RO: text and ro-data */
2061 mod->core_size = debug_align(mod->core_size);
2062 mod->core_ro_size = mod->core_size;
2063 break;
2064 case 3: /* whole core */
2065 mod->core_size = debug_align(mod->core_size);
2066 break;
2067 }
2068 }
2069
2070 pr_debug("Init section allocation order:\n");
2071 for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2072 for (i = 0; i < info->hdr->e_shnum; ++i) {
2073 Elf_Shdr *s = &info->sechdrs[i];
2074 const char *sname = info->secstrings + s->sh_name;
2075
2076 if ((s->sh_flags & masks[m][0]) != masks[m][0]
2077 || (s->sh_flags & masks[m][1])
2078 || s->sh_entsize != ~0UL
2079 || !strstarts(sname, ".init"))
2080 continue;
2081 s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
2082 | INIT_OFFSET_MASK);
2083 pr_debug("\t%s\n", sname);
2084 }
2085 switch (m) {
2086 case 0: /* executable */
2087 mod->init_size = debug_align(mod->init_size);
2088 mod->init_text_size = mod->init_size;
2089 break;
2090 case 1: /* RO: text and ro-data */
2091 mod->init_size = debug_align(mod->init_size);
2092 mod->init_ro_size = mod->init_size;
2093 break;
2094 case 3: /* whole init */
2095 mod->init_size = debug_align(mod->init_size);
2096 break;
2097 }
2098 }
2099 }
2100
2101 static void set_license(struct module *mod, const char *license)
2102 {
2103 if (!license)
2104 license = "unspecified";
2105
2106 if (!license_is_gpl_compatible(license)) {
2107 if (!test_taint(TAINT_PROPRIETARY_MODULE))
2108 printk(KERN_WARNING "%s: module license '%s' taints "
2109 "kernel.\n", mod->name, license);
2110 add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
2111 }
2112 }
2113
2114 /* Parse tag=value strings from .modinfo section */
2115 static char *next_string(char *string, unsigned long *secsize)
2116 {
2117 /* Skip non-zero chars */
2118 while (string[0]) {
2119 string++;
2120 if ((*secsize)-- <= 1)
2121 return NULL;
2122 }
2123
2124 /* Skip any zero padding. */
2125 while (!string[0]) {
2126 string++;
2127 if ((*secsize)-- <= 1)
2128 return NULL;
2129 }
2130 return string;
2131 }
2132
2133 static char *get_modinfo(struct load_info *info, const char *tag)
2134 {
2135 char *p;
2136 unsigned int taglen = strlen(tag);
2137 Elf_Shdr *infosec = &info->sechdrs[info->index.info];
2138 unsigned long size = infosec->sh_size;
2139
2140 for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) {
2141 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
2142 return p + taglen + 1;
2143 }
2144 return NULL;
2145 }
2146
2147 static void setup_modinfo(struct module *mod, struct load_info *info)
2148 {
2149 struct module_attribute *attr;
2150 int i;
2151
2152 for (i = 0; (attr = modinfo_attrs[i]); i++) {
2153 if (attr->setup)
2154 attr->setup(mod, get_modinfo(info, attr->attr.name));
2155 }
2156 }
2157
2158 static void free_modinfo(struct module *mod)
2159 {
2160 struct module_attribute *attr;
2161 int i;
2162
2163 for (i = 0; (attr = modinfo_attrs[i]); i++) {
2164 if (attr->free)
2165 attr->free(mod);
2166 }
2167 }
2168
2169 #ifdef CONFIG_KALLSYMS
2170
2171 /* lookup symbol in given range of kernel_symbols */
2172 static const struct kernel_symbol *lookup_symbol(const char *name,
2173 const struct kernel_symbol *start,
2174 const struct kernel_symbol *stop)
2175 {
2176 return bsearch(name, start, stop - start,
2177 sizeof(struct kernel_symbol), cmp_name);
2178 }
2179
2180 static int is_exported(const char *name, unsigned long value,
2181 const struct module *mod)
2182 {
2183 const struct kernel_symbol *ks;
2184 if (!mod)
2185 ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
2186 else
2187 ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
2188 return ks != NULL && ks->value == value;
2189 }
2190
2191 /* As per nm */
2192 static char elf_type(const Elf_Sym *sym, const struct load_info *info)
2193 {
2194 const Elf_Shdr *sechdrs = info->sechdrs;
2195
2196 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
2197 if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
2198 return 'v';
2199 else
2200 return 'w';
2201 }
2202 if (sym->st_shndx == SHN_UNDEF)
2203 return 'U';
2204 if (sym->st_shndx == SHN_ABS)
2205 return 'a';
2206 if (sym->st_shndx >= SHN_LORESERVE)
2207 return '?';
2208 if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
2209 return 't';
2210 if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
2211 && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
2212 if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
2213 return 'r';
2214 else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2215 return 'g';
2216 else
2217 return 'd';
2218 }
2219 if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
2220 if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2221 return 's';
2222 else
2223 return 'b';
2224 }
2225 if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name,
2226 ".debug")) {
2227 return 'n';
2228 }
2229 return '?';
2230 }
2231
2232 static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
2233 unsigned int shnum)
2234 {
2235 const Elf_Shdr *sec;
2236
2237 if (src->st_shndx == SHN_UNDEF
2238 || src->st_shndx >= shnum
2239 || !src->st_name)
2240 return false;
2241
2242 sec = sechdrs + src->st_shndx;
2243 if (!(sec->sh_flags & SHF_ALLOC)
2244 #ifndef CONFIG_KALLSYMS_ALL
2245 || !(sec->sh_flags & SHF_EXECINSTR)
2246 #endif
2247 || (sec->sh_entsize & INIT_OFFSET_MASK))
2248 return false;
2249
2250 return true;
2251 }
2252
2253 /*
2254 * We only allocate and copy the strings needed by the parts of symtab
2255 * we keep. This is simple, but has the effect of making multiple
2256 * copies of duplicates. We could be more sophisticated, see
2257 * linux-kernel thread starting with
2258 * <73defb5e4bca04a6431392cc341112b1@localhost>.
2259 */
2260 static void layout_symtab(struct module *mod, struct load_info *info)
2261 {
2262 Elf_Shdr *symsect = info->sechdrs + info->index.sym;
2263 Elf_Shdr *strsect = info->sechdrs + info->index.str;
2264 const Elf_Sym *src;
2265 unsigned int i, nsrc, ndst, strtab_size;
2266
2267 /* Put symbol section at end of init part of module. */
2268 symsect->sh_flags |= SHF_ALLOC;
2269 symsect->sh_entsize = get_offset(mod, &mod->init_size, symsect,
2270 info->index.sym) | INIT_OFFSET_MASK;
2271 pr_debug("\t%s\n", info->secstrings + symsect->sh_name);
2272
2273 src = (void *)info->hdr + symsect->sh_offset;
2274 nsrc = symsect->sh_size / sizeof(*src);
2275
2276 /* Compute total space required for the core symbols' strtab. */
2277 for (ndst = i = strtab_size = 1; i < nsrc; ++i, ++src)
2278 if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) {
2279 strtab_size += strlen(&info->strtab[src->st_name]) + 1;
2280 ndst++;
2281 }
2282
2283 /* Append room for core symbols at end of core part. */
2284 info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
2285 info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
2286 mod->core_size += strtab_size;
2287
2288 /* Put string table section at end of init part of module. */
2289 strsect->sh_flags |= SHF_ALLOC;
2290 strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
2291 info->index.str) | INIT_OFFSET_MASK;
2292 pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
2293 }
2294
2295 static void add_kallsyms(struct module *mod, const struct load_info *info)
2296 {
2297 unsigned int i, ndst;
2298 const Elf_Sym *src;
2299 Elf_Sym *dst;
2300 char *s;
2301 Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
2302
2303 mod->symtab = (void *)symsec->sh_addr;
2304 mod->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
2305 /* Make sure we get permanent strtab: don't use info->strtab. */
2306 mod->strtab = (void *)info->sechdrs[info->index.str].sh_addr;
2307
2308 /* Set types up while we still have access to sections. */
2309 for (i = 0; i < mod->num_symtab; i++)
2310 mod->symtab[i].st_info = elf_type(&mod->symtab[i], info);
2311
2312 mod->core_symtab = dst = mod->module_core + info->symoffs;
2313 mod->core_strtab = s = mod->module_core + info->stroffs;
2314 src = mod->symtab;
2315 *dst = *src;
2316 *s++ = 0;
2317 for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) {
2318 if (!is_core_symbol(src, info->sechdrs, info->hdr->e_shnum))
2319 continue;
2320
2321 dst[ndst] = *src;
2322 dst[ndst++].st_name = s - mod->core_strtab;
2323 s += strlcpy(s, &mod->strtab[src->st_name], KSYM_NAME_LEN) + 1;
2324 }
2325 mod->core_num_syms = ndst;
2326 }
2327 #else
2328 static inline void layout_symtab(struct module *mod, struct load_info *info)
2329 {
2330 }
2331
2332 static void add_kallsyms(struct module *mod, const struct load_info *info)
2333 {
2334 }
2335 #endif /* CONFIG_KALLSYMS */
2336
2337 static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
2338 {
2339 if (!debug)
2340 return;
2341 #ifdef CONFIG_DYNAMIC_DEBUG
2342 if (ddebug_add_module(debug, num, debug->modname))
2343 printk(KERN_ERR "dynamic debug error adding module: %s\n",
2344 debug->modname);
2345 #endif
2346 }
2347
2348 static void dynamic_debug_remove(struct _ddebug *debug)
2349 {
2350 if (debug)
2351 ddebug_remove_module(debug->modname);
2352 }
2353
2354 void * __weak module_alloc(unsigned long size)
2355 {
2356 return size == 0 ? NULL : vmalloc_exec(size);
2357 }
2358
2359 static void *module_alloc_update_bounds(unsigned long size)
2360 {
2361 void *ret = module_alloc(size);
2362
2363 if (ret) {
2364 mutex_lock(&module_mutex);
2365 /* Update module bounds. */
2366 if ((unsigned long)ret < module_addr_min)
2367 module_addr_min = (unsigned long)ret;
2368 if ((unsigned long)ret + size > module_addr_max)
2369 module_addr_max = (unsigned long)ret + size;
2370 mutex_unlock(&module_mutex);
2371 }
2372 return ret;
2373 }
2374
2375 #ifdef CONFIG_DEBUG_KMEMLEAK
2376 static void kmemleak_load_module(const struct module *mod,
2377 const struct load_info *info)
2378 {
2379 unsigned int i;
2380
2381 /* only scan the sections containing data */
2382 kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
2383
2384 for (i = 1; i < info->hdr->e_shnum; i++) {
2385 const char *name = info->secstrings + info->sechdrs[i].sh_name;
2386 if (!(info->sechdrs[i].sh_flags & SHF_ALLOC))
2387 continue;
2388 if (!strstarts(name, ".data") && !strstarts(name, ".bss"))
2389 continue;
2390
2391 kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
2392 info->sechdrs[i].sh_size, GFP_KERNEL);
2393 }
2394 }
2395 #else
2396 static inline void kmemleak_load_module(const struct module *mod,
2397 const struct load_info *info)
2398 {
2399 }
2400 #endif
2401
2402 /* Sets info->hdr and info->len. */
2403 static int copy_and_check(struct load_info *info,
2404 const void __user *umod, unsigned long len,
2405 const char __user *uargs)
2406 {
2407 int err;
2408 Elf_Ehdr *hdr;
2409
2410 if (len < sizeof(*hdr))
2411 return -ENOEXEC;
2412
2413 /* Suck in entire file: we'll want most of it. */
2414 if ((hdr = vmalloc(len)) == NULL)
2415 return -ENOMEM;
2416
2417 if (copy_from_user(hdr, umod, len) != 0) {
2418 err = -EFAULT;
2419 goto free_hdr;
2420 }
2421
2422 /* Sanity checks against insmoding binaries or wrong arch,
2423 weird elf version */
2424 if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
2425 || hdr->e_type != ET_REL
2426 || !elf_check_arch(hdr)
2427 || hdr->e_shentsize != sizeof(Elf_Shdr)) {
2428 err = -ENOEXEC;
2429 goto free_hdr;
2430 }
2431
2432 if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr)) {
2433 err = -ENOEXEC;
2434 goto free_hdr;
2435 }
2436
2437 info->hdr = hdr;
2438 info->len = len;
2439 return 0;
2440
2441 free_hdr:
2442 vfree(hdr);
2443 return err;
2444 }
2445
2446 static void free_copy(struct load_info *info)
2447 {
2448 vfree(info->hdr);
2449 }
2450
2451 static int rewrite_section_headers(struct load_info *info)
2452 {
2453 unsigned int i;
2454
2455 /* This should always be true, but let's be sure. */
2456 info->sechdrs[0].sh_addr = 0;
2457
2458 for (i = 1; i < info->hdr->e_shnum; i++) {
2459 Elf_Shdr *shdr = &info->sechdrs[i];
2460 if (shdr->sh_type != SHT_NOBITS
2461 && info->len < shdr->sh_offset + shdr->sh_size) {
2462 printk(KERN_ERR "Module len %lu truncated\n",
2463 info->len);
2464 return -ENOEXEC;
2465 }
2466
2467 /* Mark all sections sh_addr with their address in the
2468 temporary image. */
2469 shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
2470
2471 #ifndef CONFIG_MODULE_UNLOAD
2472 /* Don't load .exit sections */
2473 if (strstarts(info->secstrings+shdr->sh_name, ".exit"))
2474 shdr->sh_flags &= ~(unsigned long)SHF_ALLOC;
2475 #endif
2476 }
2477
2478 /* Track but don't keep modinfo and version sections. */
2479 info->index.vers = find_sec(info, "__versions");
2480 info->index.info = find_sec(info, ".modinfo");
2481 info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
2482 info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
2483 return 0;
2484 }
2485
2486 /*
2487 * Set up our basic convenience variables (pointers to section headers,
2488 * search for module section index etc), and do some basic section
2489 * verification.
2490 *
2491 * Return the temporary module pointer (we'll replace it with the final
2492 * one when we move the module sections around).
2493 */
2494 static struct module *setup_load_info(struct load_info *info)
2495 {
2496 unsigned int i;
2497 int err;
2498 struct module *mod;
2499
2500 /* Set up the convenience variables */
2501 info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
2502 info->secstrings = (void *)info->hdr
2503 + info->sechdrs[info->hdr->e_shstrndx].sh_offset;
2504
2505 err = rewrite_section_headers(info);
2506 if (err)
2507 return ERR_PTR(err);
2508
2509 /* Find internal symbols and strings. */
2510 for (i = 1; i < info->hdr->e_shnum; i++) {
2511 if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
2512 info->index.sym = i;
2513 info->index.str = info->sechdrs[i].sh_link;
2514 info->strtab = (char *)info->hdr
2515 + info->sechdrs[info->index.str].sh_offset;
2516 break;
2517 }
2518 }
2519
2520 info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
2521 if (!info->index.mod) {
2522 printk(KERN_WARNING "No module found in object\n");
2523 return ERR_PTR(-ENOEXEC);
2524 }
2525 /* This is temporary: point mod into copy of data. */
2526 mod = (void *)info->sechdrs[info->index.mod].sh_addr;
2527
2528 if (info->index.sym == 0) {
2529 printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
2530 mod->name);
2531 return ERR_PTR(-ENOEXEC);
2532 }
2533
2534 info->index.pcpu = find_pcpusec(info);
2535
2536 /* Check module struct version now, before we try to use module. */
2537 if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
2538 return ERR_PTR(-ENOEXEC);
2539
2540 return mod;
2541 }
2542
2543 static int check_modinfo(struct module *mod, struct load_info *info)
2544 {
2545 const char *modmagic = get_modinfo(info, "vermagic");
2546 int err;
2547
2548 /* This is allowed: modprobe --force will invalidate it. */
2549 if (!modmagic) {
2550 err = try_to_force_load(mod, "bad vermagic");
2551 if (err)
2552 return err;
2553 } else if (!same_magic(modmagic, vermagic, info->index.vers)) {
2554 printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
2555 mod->name, modmagic, vermagic);
2556 return -ENOEXEC;
2557 }
2558
2559 if (!get_modinfo(info, "intree"))
2560 add_taint_module(mod, TAINT_OOT_MODULE);
2561
2562 if (get_modinfo(info, "staging")) {
2563 add_taint_module(mod, TAINT_CRAP);
2564 printk(KERN_WARNING "%s: module is from the staging directory,"
2565 " the quality is unknown, you have been warned.\n",
2566 mod->name);
2567 }
2568
2569 /* Set up license info based on the info section */
2570 set_license(mod, get_modinfo(info, "license"));
2571
2572 return 0;
2573 }
2574
2575 static void find_module_sections(struct module *mod, struct load_info *info)
2576 {
2577 mod->kp = section_objs(info, "__param",
2578 sizeof(*mod->kp), &mod->num_kp);
2579 mod->syms = section_objs(info, "__ksymtab",
2580 sizeof(*mod->syms), &mod->num_syms);
2581 mod->crcs = section_addr(info, "__kcrctab");
2582 mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
2583 sizeof(*mod->gpl_syms),
2584 &mod->num_gpl_syms);
2585 mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
2586 mod->gpl_future_syms = section_objs(info,
2587 "__ksymtab_gpl_future",
2588 sizeof(*mod->gpl_future_syms),
2589 &mod->num_gpl_future_syms);
2590 mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
2591
2592 #ifdef CONFIG_UNUSED_SYMBOLS
2593 mod->unused_syms = section_objs(info, "__ksymtab_unused",
2594 sizeof(*mod->unused_syms),
2595 &mod->num_unused_syms);
2596 mod->unused_crcs = section_addr(info, "__kcrctab_unused");
2597 mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
2598 sizeof(*mod->unused_gpl_syms),
2599 &mod->num_unused_gpl_syms);
2600 mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
2601 #endif
2602 #ifdef CONFIG_CONSTRUCTORS
2603 mod->ctors = section_objs(info, ".ctors",
2604 sizeof(*mod->ctors), &mod->num_ctors);
2605 #endif
2606
2607 #ifdef CONFIG_TRACEPOINTS
2608 mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
2609 sizeof(*mod->tracepoints_ptrs),
2610 &mod->num_tracepoints);
2611 #endif
2612 #ifdef HAVE_JUMP_LABEL
2613 mod->jump_entries = section_objs(info, "__jump_table",
2614 sizeof(*mod->jump_entries),
2615 &mod->num_jump_entries);
2616 #endif
2617 #ifdef CONFIG_EVENT_TRACING
2618 mod->trace_events = section_objs(info, "_ftrace_events",
2619 sizeof(*mod->trace_events),
2620 &mod->num_trace_events);
2621 /*
2622 * This section contains pointers to allocated objects in the trace
2623 * code and not scanning it leads to false positives.
2624 */
2625 kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
2626 mod->num_trace_events, GFP_KERNEL);
2627 #endif
2628 #ifdef CONFIG_TRACING
2629 mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
2630 sizeof(*mod->trace_bprintk_fmt_start),
2631 &mod->num_trace_bprintk_fmt);
2632 /*
2633 * This section contains pointers to allocated objects in the trace
2634 * code and not scanning it leads to false positives.
2635 */
2636 kmemleak_scan_area(mod->trace_bprintk_fmt_start,
2637 sizeof(*mod->trace_bprintk_fmt_start) *
2638 mod->num_trace_bprintk_fmt, GFP_KERNEL);
2639 #endif
2640 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
2641 /* sechdrs[0].sh_size is always zero */
2642 mod->ftrace_callsites = section_objs(info, "__mcount_loc",
2643 sizeof(*mod->ftrace_callsites),
2644 &mod->num_ftrace_callsites);
2645 #endif
2646
2647 mod->extable = section_objs(info, "__ex_table",
2648 sizeof(*mod->extable), &mod->num_exentries);
2649
2650 if (section_addr(info, "__obsparm"))
2651 printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
2652 mod->name);
2653
2654 info->debug = section_objs(info, "__verbose",
2655 sizeof(*info->debug), &info->num_debug);
2656 }
2657
2658 static int move_module(struct module *mod, struct load_info *info)
2659 {
2660 int i;
2661 void *ptr;
2662
2663 /* Do the allocs. */
2664 ptr = module_alloc_update_bounds(mod->core_size);
2665 /*
2666 * The pointer to this block is stored in the module structure
2667 * which is inside the block. Just mark it as not being a
2668 * leak.
2669 */
2670 kmemleak_not_leak(ptr);
2671 if (!ptr)
2672 return -ENOMEM;
2673
2674 memset(ptr, 0, mod->core_size);
2675 mod->module_core = ptr;
2676
2677 ptr = module_alloc_update_bounds(mod->init_size);
2678 /*
2679 * The pointer to this block is stored in the module structure
2680 * which is inside the block. This block doesn't need to be
2681 * scanned as it contains data and code that will be freed
2682 * after the module is initialized.
2683 */
2684 kmemleak_ignore(ptr);
2685 if (!ptr && mod->init_size) {
2686 module_free(mod, mod->module_core);
2687 return -ENOMEM;
2688 }
2689 memset(ptr, 0, mod->init_size);
2690 mod->module_init = ptr;
2691
2692 /* Transfer each section which specifies SHF_ALLOC */
2693 pr_debug("final section addresses:\n");
2694 for (i = 0; i < info->hdr->e_shnum; i++) {
2695 void *dest;
2696 Elf_Shdr *shdr = &info->sechdrs[i];
2697
2698 if (!(shdr->sh_flags & SHF_ALLOC))
2699 continue;
2700
2701 if (shdr->sh_entsize & INIT_OFFSET_MASK)
2702 dest = mod->module_init
2703 + (shdr->sh_entsize & ~INIT_OFFSET_MASK);
2704 else
2705 dest = mod->module_core + shdr->sh_entsize;
2706
2707 if (shdr->sh_type != SHT_NOBITS)
2708 memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
2709 /* Update sh_addr to point to copy in image. */
2710 shdr->sh_addr = (unsigned long)dest;
2711 pr_debug("\t0x%lx %s\n",
2712 (long)shdr->sh_addr, info->secstrings + shdr->sh_name);
2713 }
2714
2715 return 0;
2716 }
2717
2718 static int check_module_license_and_versions(struct module *mod)
2719 {
2720 /*
2721 * ndiswrapper is under GPL by itself, but loads proprietary modules.
2722 * Don't use add_taint_module(), as it would prevent ndiswrapper from
2723 * using GPL-only symbols it needs.
2724 */
2725 if (strcmp(mod->name, "ndiswrapper") == 0)
2726 add_taint(TAINT_PROPRIETARY_MODULE);
2727
2728 /* driverloader was caught wrongly pretending to be under GPL */
2729 if (strcmp(mod->name, "driverloader") == 0)
2730 add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
2731
2732 #ifdef CONFIG_MODVERSIONS
2733 if ((mod->num_syms && !mod->crcs)
2734 || (mod->num_gpl_syms && !mod->gpl_crcs)
2735 || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
2736 #ifdef CONFIG_UNUSED_SYMBOLS
2737 || (mod->num_unused_syms && !mod->unused_crcs)
2738 || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
2739 #endif
2740 ) {
2741 return try_to_force_load(mod,
2742 "no versions for exported symbols");
2743 }
2744 #endif
2745 return 0;
2746 }
2747
2748 static void flush_module_icache(const struct module *mod)
2749 {
2750 mm_segment_t old_fs;
2751
2752 /* flush the icache in correct context */
2753 old_fs = get_fs();
2754 set_fs(KERNEL_DS);
2755
2756 /*
2757 * Flush the instruction cache, since we've played with text.
2758 * Do it before processing of module parameters, so the module
2759 * can provide parameter accessor functions of its own.
2760 */
2761 if (mod->module_init)
2762 flush_icache_range((unsigned long)mod->module_init,
2763 (unsigned long)mod->module_init
2764 + mod->init_size);
2765 flush_icache_range((unsigned long)mod->module_core,
2766 (unsigned long)mod->module_core + mod->core_size);
2767
2768 set_fs(old_fs);
2769 }
2770
2771 int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
2772 Elf_Shdr *sechdrs,
2773 char *secstrings,
2774 struct module *mod)
2775 {
2776 return 0;
2777 }
2778
2779 static struct module *layout_and_allocate(struct load_info *info)
2780 {
2781 /* Module within temporary copy. */
2782 struct module *mod;
2783 Elf_Shdr *pcpusec;
2784 int err;
2785
2786 mod = setup_load_info(info);
2787 if (IS_ERR(mod))
2788 return mod;
2789
2790 err = check_modinfo(mod, info);
2791 if (err)
2792 return ERR_PTR(err);
2793
2794 /* Allow arches to frob section contents and sizes. */
2795 err = module_frob_arch_sections(info->hdr, info->sechdrs,
2796 info->secstrings, mod);
2797 if (err < 0)
2798 goto out;
2799
2800 pcpusec = &info->sechdrs[info->index.pcpu];
2801 if (pcpusec->sh_size) {
2802 /* We have a special allocation for this section. */
2803 err = percpu_modalloc(mod,
2804 pcpusec->sh_size, pcpusec->sh_addralign);
2805 if (err)
2806 goto out;
2807 pcpusec->sh_flags &= ~(unsigned long)SHF_ALLOC;
2808 }
2809
2810 /* Determine total sizes, and put offsets in sh_entsize. For now
2811 this is done generically; there doesn't appear to be any
2812 special cases for the architectures. */
2813 layout_sections(mod, info);
2814 layout_symtab(mod, info);
2815
2816 /* Allocate and move to the final place */
2817 err = move_module(mod, info);
2818 if (err)
2819 goto free_percpu;
2820
2821 /* Module has been copied to its final place now: return it. */
2822 mod = (void *)info->sechdrs[info->index.mod].sh_addr;
2823 kmemleak_load_module(mod, info);
2824 return mod;
2825
2826 free_percpu:
2827 percpu_modfree(mod);
2828 out:
2829 return ERR_PTR(err);
2830 }
2831
2832 /* mod is no longer valid after this! */
2833 static void module_deallocate(struct module *mod, struct load_info *info)
2834 {
2835 percpu_modfree(mod);
2836 module_free(mod, mod->module_init);
2837 module_free(mod, mod->module_core);
2838 }
2839
2840 int __weak module_finalize(const Elf_Ehdr *hdr,
2841 const Elf_Shdr *sechdrs,
2842 struct module *me)
2843 {
2844 return 0;
2845 }
2846
2847 static int post_relocation(struct module *mod, const struct load_info *info)
2848 {
2849 /* Sort exception table now relocations are done. */
2850 sort_extable(mod->extable, mod->extable + mod->num_exentries);
2851
2852 /* Copy relocated percpu area over. */
2853 percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
2854 info->sechdrs[info->index.pcpu].sh_size);
2855
2856 /* Setup kallsyms-specific fields. */
2857 add_kallsyms(mod, info);
2858
2859 /* Arch-specific module finalizing. */
2860 return module_finalize(info->hdr, info->sechdrs, mod);
2861 }
2862
2863 /* Allocate and load the module: note that size of section 0 is always
2864 zero, and we rely on this for optional sections. */
2865 static struct module *load_module(void __user *umod,
2866 unsigned long len,
2867 const char __user *uargs)
2868 {
2869 struct load_info info = { NULL, };
2870 struct module *mod;
2871 long err;
2872
2873 pr_debug("load_module: umod=%p, len=%lu, uargs=%p\n",
2874 umod, len, uargs);
2875
2876 /* Copy in the blobs from userspace, check they are vaguely sane. */
2877 err = copy_and_check(&info, umod, len, uargs);
2878 if (err)
2879 return ERR_PTR(err);
2880
2881 /* Figure out module layout, and allocate all the memory. */
2882 mod = layout_and_allocate(&info);
2883 if (IS_ERR(mod)) {
2884 err = PTR_ERR(mod);
2885 goto free_copy;
2886 }
2887
2888 /* Now module is in final location, initialize linked lists, etc. */
2889 err = module_unload_init(mod);
2890 if (err)
2891 goto free_module;
2892
2893 /* Now we've got everything in the final locations, we can
2894 * find optional sections. */
2895 find_module_sections(mod, &info);
2896
2897 err = check_module_license_and_versions(mod);
2898 if (err)
2899 goto free_unload;
2900
2901 /* Set up MODINFO_ATTR fields */
2902 setup_modinfo(mod, &info);
2903
2904 /* Fix up syms, so that st_value is a pointer to location. */
2905 err = simplify_symbols(mod, &info);
2906 if (err < 0)
2907 goto free_modinfo;
2908
2909 err = apply_relocations(mod, &info);
2910 if (err < 0)
2911 goto free_modinfo;
2912
2913 err = post_relocation(mod, &info);
2914 if (err < 0)
2915 goto free_modinfo;
2916
2917 flush_module_icache(mod);
2918
2919 /* Now copy in args */
2920 mod->args = strndup_user(uargs, ~0UL >> 1);
2921 if (IS_ERR(mod->args)) {
2922 err = PTR_ERR(mod->args);
2923 goto free_arch_cleanup;
2924 }
2925
2926 /* Mark state as coming so strong_try_module_get() ignores us. */
2927 mod->state = MODULE_STATE_COMING;
2928
2929 /* Now sew it into the lists so we can get lockdep and oops
2930 * info during argument parsing. No one should access us, since
2931 * strong_try_module_get() will fail.
2932 * lockdep/oops can run asynchronous, so use the RCU list insertion
2933 * function to insert in a way safe to concurrent readers.
2934 * The mutex protects against concurrent writers.
2935 */
2936 mutex_lock(&module_mutex);
2937 if (find_module(mod->name)) {
2938 err = -EEXIST;
2939 goto unlock;
2940 }
2941
2942 /* This has to be done once we're sure module name is unique. */
2943 dynamic_debug_setup(info.debug, info.num_debug);
2944
2945 /* Find duplicate symbols */
2946 err = verify_export_symbols(mod);
2947 if (err < 0)
2948 goto ddebug;
2949
2950 module_bug_finalize(info.hdr, info.sechdrs, mod);
2951 list_add_rcu(&mod->list, &modules);
2952 mutex_unlock(&module_mutex);
2953
2954 /* Module is ready to execute: parsing args may do that. */
2955 err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
2956 -32768, 32767, NULL);
2957 if (err < 0)
2958 goto unlink;
2959
2960 /* Link in to syfs. */
2961 err = mod_sysfs_setup(mod, &info, mod->kp, mod->num_kp);
2962 if (err < 0)
2963 goto unlink;
2964
2965 /* Get rid of temporary copy. */
2966 free_copy(&info);
2967
2968 /* Done! */
2969 trace_module_load(mod);
2970 return mod;
2971
2972 unlink:
2973 mutex_lock(&module_mutex);
2974 /* Unlink carefully: kallsyms could be walking list. */
2975 list_del_rcu(&mod->list);
2976 module_bug_cleanup(mod);
2977
2978 ddebug:
2979 dynamic_debug_remove(info.debug);
2980 unlock:
2981 mutex_unlock(&module_mutex);
2982 synchronize_sched();
2983 kfree(mod->args);
2984 free_arch_cleanup:
2985 module_arch_cleanup(mod);
2986 free_modinfo:
2987 free_modinfo(mod);
2988 free_unload:
2989 module_unload_free(mod);
2990 free_module:
2991 module_deallocate(mod, &info);
2992 free_copy:
2993 free_copy(&info);
2994 return ERR_PTR(err);
2995 }
2996
2997 /* Call module constructors. */
2998 static void do_mod_ctors(struct module *mod)
2999 {
3000 #ifdef CONFIG_CONSTRUCTORS
3001 unsigned long i;
3002
3003 for (i = 0; i < mod->num_ctors; i++)
3004 mod->ctors[i]();
3005 #endif
3006 }
3007
3008 /* This is where the real work happens */
3009 SYSCALL_DEFINE3(init_module, void __user *, umod,
3010 unsigned long, len, const char __user *, uargs)
3011 {
3012 struct module *mod;
3013 int ret = 0;
3014
3015 /* Must have permission */
3016 if (!capable(CAP_SYS_MODULE) || modules_disabled)
3017 return -EPERM;
3018
3019 /* Do all the hard work */
3020 mod = load_module(umod, len, uargs);
3021 if (IS_ERR(mod))
3022 return PTR_ERR(mod);
3023
3024 blocking_notifier_call_chain(&module_notify_list,
3025 MODULE_STATE_COMING, mod);
3026
3027 /* Set RO and NX regions for core */
3028 set_section_ro_nx(mod->module_core,
3029 mod->core_text_size,
3030 mod->core_ro_size,
3031 mod->core_size);
3032
3033 /* Set RO and NX regions for init */
3034 set_section_ro_nx(mod->module_init,
3035 mod->init_text_size,
3036 mod->init_ro_size,
3037 mod->init_size);
3038
3039 do_mod_ctors(mod);
3040 /* Start the module */
3041 if (mod->init != NULL)
3042 ret = do_one_initcall(mod->init);
3043 if (ret < 0) {
3044 /* Init routine failed: abort. Try to protect us from
3045 buggy refcounters. */
3046 mod->state = MODULE_STATE_GOING;
3047 synchronize_sched();
3048 module_put(mod);
3049 blocking_notifier_call_chain(&module_notify_list,
3050 MODULE_STATE_GOING, mod);
3051 free_module(mod);
3052 wake_up(&module_wq);
3053 return ret;
3054 }
3055 if (ret > 0) {
3056 printk(KERN_WARNING
3057 "%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n"
3058 "%s: loading module anyway...\n",
3059 __func__, mod->name, ret,
3060 __func__);
3061 dump_stack();
3062 }
3063
3064 /* Now it's a first class citizen! Wake up anyone waiting for it. */
3065 mod->state = MODULE_STATE_LIVE;
3066 wake_up(&module_wq);
3067 blocking_notifier_call_chain(&module_notify_list,
3068 MODULE_STATE_LIVE, mod);
3069
3070 /* We need to finish all async code before the module init sequence is done */
3071 async_synchronize_full();
3072
3073 mutex_lock(&module_mutex);
3074 /* Drop initial reference. */
3075 module_put(mod);
3076 trim_init_extable(mod);
3077 #ifdef CONFIG_KALLSYMS
3078 mod->num_symtab = mod->core_num_syms;
3079 mod->symtab = mod->core_symtab;
3080 mod->strtab = mod->core_strtab;
3081 #endif
3082 unset_module_init_ro_nx(mod);
3083 module_free(mod, mod->module_init);
3084 mod->module_init = NULL;
3085 mod->init_size = 0;
3086 mod->init_ro_size = 0;
3087 mod->init_text_size = 0;
3088 mutex_unlock(&module_mutex);
3089
3090 return 0;
3091 }
3092
3093 static inline int within(unsigned long addr, void *start, unsigned long size)
3094 {
3095 return ((void *)addr >= start && (void *)addr < start + size);
3096 }
3097
3098 #ifdef CONFIG_KALLSYMS
3099 /*
3100 * This ignores the intensely annoying "mapping symbols" found
3101 * in ARM ELF files: $a, $t and $d.
3102 */
3103 static inline int is_arm_mapping_symbol(const char *str)
3104 {
3105 return str[0] == '$' && strchr("atd", str[1])
3106 && (str[2] == '\0' || str[2] == '.');
3107 }
3108
3109 static const char *get_ksymbol(struct module *mod,
3110 unsigned long addr,
3111 unsigned long *size,
3112 unsigned long *offset)
3113 {
3114 unsigned int i, best = 0;
3115 unsigned long nextval;
3116
3117 /* At worse, next value is at end of module */
3118 if (within_module_init(addr, mod))
3119 nextval = (unsigned long)mod->module_init+mod->init_text_size;
3120 else
3121 nextval = (unsigned long)mod->module_core+mod->core_text_size;
3122
3123 /* Scan for closest preceding symbol, and next symbol. (ELF
3124 starts real symbols at 1). */
3125 for (i = 1; i < mod->num_symtab; i++) {
3126 if (mod->symtab[i].st_shndx == SHN_UNDEF)
3127 continue;
3128
3129 /* We ignore unnamed symbols: they're uninformative
3130 * and inserted at a whim. */
3131 if (mod->symtab[i].st_value <= addr
3132 && mod->symtab[i].st_value > mod->symtab[best].st_value
3133 && *(mod->strtab + mod->symtab[i].st_name) != '\0'
3134 && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
3135 best = i;
3136 if (mod->symtab[i].st_value > addr
3137 && mod->symtab[i].st_value < nextval
3138 && *(mod->strtab + mod->symtab[i].st_name) != '\0'
3139 && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
3140 nextval = mod->symtab[i].st_value;
3141 }
3142
3143 if (!best)
3144 return NULL;
3145
3146 if (size)
3147 *size = nextval - mod->symtab[best].st_value;
3148 if (offset)
3149 *offset = addr - mod->symtab[best].st_value;
3150 return mod->strtab + mod->symtab[best].st_name;
3151 }
3152
3153 /* For kallsyms to ask for address resolution. NULL means not found. Careful
3154 * not to lock to avoid deadlock on oopses, simply disable preemption. */
3155 const char *module_address_lookup(unsigned long addr,
3156 unsigned long *size,
3157 unsigned long *offset,
3158 char **modname,
3159 char *namebuf)
3160 {
3161 struct module *mod;
3162 const char *ret = NULL;
3163
3164 preempt_disable();
3165 list_for_each_entry_rcu(mod, &modules, list) {
3166 if (within_module_init(addr, mod) ||
3167 within_module_core(addr, mod)) {
3168 if (modname)
3169 *modname = mod->name;
3170 ret = get_ksymbol(mod, addr, size, offset);
3171 break;
3172 }
3173 }
3174 /* Make a copy in here where it's safe */
3175 if (ret) {
3176 strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
3177 ret = namebuf;
3178 }
3179 preempt_enable();
3180 return ret;
3181 }
3182
3183 int lookup_module_symbol_name(unsigned long addr, char *symname)
3184 {
3185 struct module *mod;
3186
3187 preempt_disable();
3188 list_for_each_entry_rcu(mod, &modules, list) {
3189 if (within_module_init(addr, mod) ||
3190 within_module_core(addr, mod)) {
3191 const char *sym;
3192
3193 sym = get_ksymbol(mod, addr, NULL, NULL);
3194 if (!sym)
3195 goto out;
3196 strlcpy(symname, sym, KSYM_NAME_LEN);
3197 preempt_enable();
3198 return 0;
3199 }
3200 }
3201 out:
3202 preempt_enable();
3203 return -ERANGE;
3204 }
3205
3206 int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
3207 unsigned long *offset, char *modname, char *name)
3208 {
3209 struct module *mod;
3210
3211 preempt_disable();
3212 list_for_each_entry_rcu(mod, &modules, list) {
3213 if (within_module_init(addr, mod) ||
3214 within_module_core(addr, mod)) {
3215 const char *sym;
3216
3217 sym = get_ksymbol(mod, addr, size, offset);
3218 if (!sym)
3219 goto out;
3220 if (modname)
3221 strlcpy(modname, mod->name, MODULE_NAME_LEN);
3222 if (name)
3223 strlcpy(name, sym, KSYM_NAME_LEN);
3224 preempt_enable();
3225 return 0;
3226 }
3227 }
3228 out:
3229 preempt_enable();
3230 return -ERANGE;
3231 }
3232
3233 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
3234 char *name, char *module_name, int *exported)
3235 {
3236 struct module *mod;
3237
3238 preempt_disable();
3239 list_for_each_entry_rcu(mod, &modules, list) {
3240 if (symnum < mod->num_symtab) {
3241 *value = mod->symtab[symnum].st_value;
3242 *type = mod->symtab[symnum].st_info;
3243 strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
3244 KSYM_NAME_LEN);
3245 strlcpy(module_name, mod->name, MODULE_NAME_LEN);
3246 *exported = is_exported(name, *value, mod);
3247 preempt_enable();
3248 return 0;
3249 }
3250 symnum -= mod->num_symtab;
3251 }
3252 preempt_enable();
3253 return -ERANGE;
3254 }
3255
3256 static unsigned long mod_find_symname(struct module *mod, const char *name)
3257 {
3258 unsigned int i;
3259
3260 for (i = 0; i < mod->num_symtab; i++)
3261 if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
3262 mod->symtab[i].st_info != 'U')
3263 return mod->symtab[i].st_value;
3264 return 0;
3265 }
3266
3267 /* Look for this name: can be of form module:name. */
3268 unsigned long module_kallsyms_lookup_name(const char *name)
3269 {
3270 struct module *mod;
3271 char *colon;
3272 unsigned long ret = 0;
3273
3274 /* Don't lock: we're in enough trouble already. */
3275 preempt_disable();
3276 if ((colon = strchr(name, ':')) != NULL) {
3277 *colon = '\0';
3278 if ((mod = find_module(name)) != NULL)
3279 ret = mod_find_symname(mod, colon+1);
3280 *colon = ':';
3281 } else {
3282 list_for_each_entry_rcu(mod, &modules, list)
3283 if ((ret = mod_find_symname(mod, name)) != 0)
3284 break;
3285 }
3286 preempt_enable();
3287 return ret;
3288 }
3289
3290 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
3291 struct module *, unsigned long),
3292 void *data)
3293 {
3294 struct module *mod;
3295 unsigned int i;
3296 int ret;
3297
3298 list_for_each_entry(mod, &modules, list) {
3299 for (i = 0; i < mod->num_symtab; i++) {
3300 ret = fn(data, mod->strtab + mod->symtab[i].st_name,
3301 mod, mod->symtab[i].st_value);
3302 if (ret != 0)
3303 return ret;
3304 }
3305 }
3306 return 0;
3307 }
3308 #endif /* CONFIG_KALLSYMS */
3309
3310 static char *module_flags(struct module *mod, char *buf)
3311 {
3312 int bx = 0;
3313
3314 if (mod->taints ||
3315 mod->state == MODULE_STATE_GOING ||
3316 mod->state == MODULE_STATE_COMING) {
3317 buf[bx++] = '(';
3318 bx += module_flags_taint(mod, buf + bx);
3319 /* Show a - for module-is-being-unloaded */
3320 if (mod->state == MODULE_STATE_GOING)
3321 buf[bx++] = '-';
3322 /* Show a + for module-is-being-loaded */
3323 if (mod->state == MODULE_STATE_COMING)
3324 buf[bx++] = '+';
3325 buf[bx++] = ')';
3326 }
3327 buf[bx] = '\0';
3328
3329 return buf;
3330 }
3331
3332 #ifdef CONFIG_PROC_FS
3333 /* Called by the /proc file system to return a list of modules. */
3334 static void *m_start(struct seq_file *m, loff_t *pos)
3335 {
3336 mutex_lock(&module_mutex);
3337 return seq_list_start(&modules, *pos);
3338 }
3339
3340 static void *m_next(struct seq_file *m, void *p, loff_t *pos)
3341 {
3342 return seq_list_next(p, &modules, pos);
3343 }
3344
3345 static void m_stop(struct seq_file *m, void *p)
3346 {
3347 mutex_unlock(&module_mutex);
3348 }
3349
3350 static int m_show(struct seq_file *m, void *p)
3351 {
3352 struct module *mod = list_entry(p, struct module, list);
3353 char buf[8];
3354
3355 seq_printf(m, "%s %u",
3356 mod->name, mod->init_size + mod->core_size);
3357 print_unload_info(m, mod);
3358
3359 /* Informative for users. */
3360 seq_printf(m, " %s",
3361 mod->state == MODULE_STATE_GOING ? "Unloading":
3362 mod->state == MODULE_STATE_COMING ? "Loading":
3363 "Live");
3364 /* Used by oprofile and other similar tools. */
3365 seq_printf(m, " 0x%pK", mod->module_core);
3366
3367 /* Taints info */
3368 if (mod->taints)
3369 seq_printf(m, " %s", module_flags(mod, buf));
3370
3371 seq_printf(m, "\n");
3372 return 0;
3373 }
3374
3375 /* Format: modulename size refcount deps address
3376
3377 Where refcount is a number or -, and deps is a comma-separated list
3378 of depends or -.
3379 */
3380 static const struct seq_operations modules_op = {
3381 .start = m_start,
3382 .next = m_next,
3383 .stop = m_stop,
3384 .show = m_show
3385 };
3386
3387 static int modules_open(struct inode *inode, struct file *file)
3388 {
3389 return seq_open(file, &modules_op);
3390 }
3391
3392 static const struct file_operations proc_modules_operations = {
3393 .open = modules_open,
3394 .read = seq_read,
3395 .llseek = seq_lseek,
3396 .release = seq_release,
3397 };
3398
3399 static int __init proc_modules_init(void)
3400 {
3401 proc_create("modules", 0, NULL, &proc_modules_operations);
3402 return 0;
3403 }
3404 module_init(proc_modules_init);
3405 #endif
3406
3407 /* Given an address, look for it in the module exception tables. */
3408 const struct exception_table_entry *search_module_extables(unsigned long addr)
3409 {
3410 const struct exception_table_entry *e = NULL;
3411 struct module *mod;
3412
3413 preempt_disable();
3414 list_for_each_entry_rcu(mod, &modules, list) {
3415 if (mod->num_exentries == 0)
3416 continue;
3417
3418 e = search_extable(mod->extable,
3419 mod->extable + mod->num_exentries - 1,
3420 addr);
3421 if (e)
3422 break;
3423 }
3424 preempt_enable();
3425
3426 /* Now, if we found one, we are running inside it now, hence
3427 we cannot unload the module, hence no refcnt needed. */
3428 return e;
3429 }
3430
3431 /*
3432 * is_module_address - is this address inside a module?
3433 * @addr: the address to check.
3434 *
3435 * See is_module_text_address() if you simply want to see if the address
3436 * is code (not data).
3437 */
3438 bool is_module_address(unsigned long addr)
3439 {
3440 bool ret;
3441
3442 preempt_disable();
3443 ret = __module_address(addr) != NULL;
3444 preempt_enable();
3445
3446 return ret;
3447 }
3448
3449 /*
3450 * __module_address - get the module which contains an address.
3451 * @addr: the address.
3452 *
3453 * Must be called with preempt disabled or module mutex held so that
3454 * module doesn't get freed during this.
3455 */
3456 struct module *__module_address(unsigned long addr)
3457 {
3458 struct module *mod;
3459
3460 if (addr < module_addr_min || addr > module_addr_max)
3461 return NULL;
3462
3463 list_for_each_entry_rcu(mod, &modules, list)
3464 if (within_module_core(addr, mod)
3465 || within_module_init(addr, mod))
3466 return mod;
3467 return NULL;
3468 }
3469 EXPORT_SYMBOL_GPL(__module_address);
3470
3471 /*
3472 * is_module_text_address - is this address inside module code?
3473 * @addr: the address to check.
3474 *
3475 * See is_module_address() if you simply want to see if the address is
3476 * anywhere in a module. See kernel_text_address() for testing if an
3477 * address corresponds to kernel or module code.
3478 */
3479 bool is_module_text_address(unsigned long addr)
3480 {
3481 bool ret;
3482
3483 preempt_disable();
3484 ret = __module_text_address(addr) != NULL;
3485 preempt_enable();
3486
3487 return ret;
3488 }
3489
3490 /*
3491 * __module_text_address - get the module whose code contains an address.
3492 * @addr: the address.
3493 *
3494 * Must be called with preempt disabled or module mutex held so that
3495 * module doesn't get freed during this.
3496 */
3497 struct module *__module_text_address(unsigned long addr)
3498 {
3499 struct module *mod = __module_address(addr);
3500 if (mod) {
3501 /* Make sure it's within the text section. */
3502 if (!within(addr, mod->module_init, mod->init_text_size)
3503 && !within(addr, mod->module_core, mod->core_text_size))
3504 mod = NULL;
3505 }
3506 return mod;
3507 }
3508 EXPORT_SYMBOL_GPL(__module_text_address);
3509
3510 /* Don't grab lock, we're oopsing. */
3511 void print_modules(void)
3512 {
3513 struct module *mod;
3514 char buf[8];
3515
3516 printk(KERN_DEFAULT "Modules linked in:");
3517 /* Most callers should already have preempt disabled, but make sure */
3518 preempt_disable();
3519 list_for_each_entry_rcu(mod, &modules, list)
3520 printk(" %s%s", mod->name, module_flags(mod, buf));
3521 preempt_enable();
3522 if (last_unloaded_module[0])
3523 printk(" [last unloaded: %s]", last_unloaded_module);
3524 printk("\n");
3525 }
3526
3527 #ifdef CONFIG_MODVERSIONS
3528 /* Generate the signature for all relevant module structures here.
3529 * If these change, we don't want to try to parse the module. */
3530 void module_layout(struct module *mod,
3531 struct modversion_info *ver,
3532 struct kernel_param *kp,
3533 struct kernel_symbol *ks,
3534 struct tracepoint * const *tp)
3535 {
3536 }
3537 EXPORT_SYMBOL(module_layout);
3538 #endif
Linus' kernel tree