module.c 99 KB
Newer Older
1
/*
Linus Torvalds's avatar
Linus Torvalds committed
2
   Copyright (C) 2002 Richard Henderson
3
   Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
Linus Torvalds's avatar
Linus Torvalds committed
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
19
#include <linux/export.h>
Linus Torvalds's avatar
Linus Torvalds committed
20
#include <linux/moduleloader.h>
21
#include <linux/ftrace_event.h>
Linus Torvalds's avatar
Linus Torvalds committed
22
#include <linux/init.h>
23
#include <linux/kallsyms.h>
24
#include <linux/file.h>
25
#include <linux/fs.h>
Roland McGrath's avatar
Roland McGrath committed
26
#include <linux/sysfs.h>
27
#include <linux/kernel.h>
Linus Torvalds's avatar
Linus Torvalds committed
28 29 30
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
31
#include <linux/proc_fs.h>
32
#include <linux/security.h>
Linus Torvalds's avatar
Linus Torvalds committed
33 34 35 36
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <linux/rcupdate.h>
37
#include <linux/capability.h>
Linus Torvalds's avatar
Linus Torvalds committed
38 39 40 41 42 43
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/vermagic.h>
#include <linux/notifier.h>
Al Viro's avatar
Al Viro committed
44
#include <linux/sched.h>
Linus Torvalds's avatar
Linus Torvalds committed
45
#include <linux/device.h>
46
#include <linux/string.h>
47
#include <linux/mutex.h>
48
#include <linux/rculist.h>
Linus Torvalds's avatar
Linus Torvalds committed
49 50
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
51
#include <asm/mmu_context.h>
52
#include <linux/license.h>
53
#include <asm/sections.h>
54
#include <linux/tracepoint.h>
55
#include <linux/ftrace.h>
56
#include <linux/async.h>
57
#include <linux/percpu.h>
58
#include <linux/kmemleak.h>
59
#include <linux/jump_label.h>
60
#include <linux/pfn.h>
61
#include <linux/bsearch.h>
62
#include <uapi/linux/module.h>
63
#include "module-internal.h"
Linus Torvalds's avatar
Linus Torvalds committed
64

65 66 67
#define CREATE_TRACE_POINTS
#include <trace/events/module.h>

Linus Torvalds's avatar
Linus Torvalds committed
68 69 70 71
#ifndef ARCH_SHF_SMALL
#define ARCH_SHF_SMALL 0
#endif

72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91
/*
 * Modules' sections will be aligned on page boundaries
 * to ensure complete separation of code and data, but
 * only when CONFIG_DEBUG_SET_MODULE_RONX=y
 */
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
# define debug_align(X) ALIGN(X, PAGE_SIZE)
#else
# define debug_align(X) (X)
#endif

/*
 * Given BASE and SIZE this macro calculates the number of pages the
 * memory regions occupies
 */
#define MOD_NUMBER_OF_PAGES(BASE, SIZE) (((SIZE) > 0) ?		\
		(PFN_DOWN((unsigned long)(BASE) + (SIZE) - 1) -	\
			 PFN_DOWN((unsigned long)BASE) + 1)	\
		: (0UL))

Linus Torvalds's avatar
Linus Torvalds committed
92 93 94
/* If this is set, the section belongs in the init part of the module */
#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))

95 96 97 98 99
/*
 * Mutex protects:
 * 1) List of modules (also safely readable with preempt_disable),
 * 2) module_use links,
 * 3) module_addr_min/module_addr_max.
100
 * (delete and add uses RCU list operations). */
101 102
DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
103
static LIST_HEAD(modules);
104 105 106 107
#ifdef CONFIG_KGDB_KDB
struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
#endif /* CONFIG_KGDB_KDB */

108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123
static void module_assert_mutex(void)
{
	lockdep_assert_held(&module_mutex);
}

static void module_assert_mutex_or_preempt(void)
{
#ifdef CONFIG_LOCKDEP
	if (unlikely(!debug_locks))
		return;

	WARN_ON(!rcu_read_lock_sched_held() &&
		!lockdep_is_held(&module_mutex));
#endif
}

124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152
#ifdef CONFIG_MODULE_SIG
#ifdef CONFIG_MODULE_SIG_FORCE
static bool sig_enforce = true;
#else
static bool sig_enforce = false;

static int param_set_bool_enable_only(const char *val,
				      const struct kernel_param *kp)
{
	int err;
	bool test;
	struct kernel_param dummy_kp = *kp;

	dummy_kp.arg = &test;

	err = param_set_bool(val, &dummy_kp);
	if (err)
		return err;

	/* Don't let them unset it once it's set! */
	if (!test && sig_enforce)
		return -EROFS;

	if (test)
		sig_enforce = true;
	return 0;
}

static const struct kernel_param_ops param_ops_bool_enable_only = {
153
	.flags = KERNEL_PARAM_OPS_FL_NOARG,
154 155 156 157 158 159 160 161
	.set = param_set_bool_enable_only,
	.get = param_get_bool,
};
#define param_check_bool_enable_only param_check_bool

module_param(sig_enforce, bool_enable_only, 0644);
#endif /* !CONFIG_MODULE_SIG_FORCE */
#endif /* CONFIG_MODULE_SIG */
Linus Torvalds's avatar
Linus Torvalds committed
162

163 164
/* Block module loading/unloading? */
int modules_disabled = 0;
165
core_param(nomodule, modules_disabled, bint, 0);
166

167 168 169
/* Waiting for a module to finish initializing? */
static DECLARE_WAIT_QUEUE_HEAD(module_wq);

170
static BLOCKING_NOTIFIER_HEAD(module_notify_list);
Linus Torvalds's avatar
Linus Torvalds committed
171

172 173
/* Bounds of module allocation, for speeding __module_address.
 * Protected by module_mutex. */
174 175
static unsigned long module_addr_min = -1UL, module_addr_max = 0;

176
int register_module_notifier(struct notifier_block *nb)
Linus Torvalds's avatar
Linus Torvalds committed
177
{
178
	return blocking_notifier_chain_register(&module_notify_list, nb);
Linus Torvalds's avatar
Linus Torvalds committed
179 180 181
}
EXPORT_SYMBOL(register_module_notifier);

182
int unregister_module_notifier(struct notifier_block *nb)
Linus Torvalds's avatar
Linus Torvalds committed
183
{
184
	return blocking_notifier_chain_unregister(&module_notify_list, nb);
Linus Torvalds's avatar
Linus Torvalds committed
185 186 187
}
EXPORT_SYMBOL(unregister_module_notifier);

188 189 190 191
struct load_info {
	Elf_Ehdr *hdr;
	unsigned long len;
	Elf_Shdr *sechdrs;
192
	char *secstrings, *strtab;
Rusty Russell's avatar
Rusty Russell committed
193
	unsigned long symoffs, stroffs;
194 195
	struct _ddebug *debug;
	unsigned int num_debug;
196
	bool sig_ok;
197 198 199 200 201
	struct {
		unsigned int sym, str, mod, vers, info, pcpu;
	} index;
};

202 203
/* We require a truly strong try_module_get(): 0 means failure due to
   ongoing or failed initialization etc. */
Linus Torvalds's avatar
Linus Torvalds committed
204 205
static inline int strong_try_module_get(struct module *mod)
{
206
	BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
Linus Torvalds's avatar
Linus Torvalds committed
207
	if (mod && mod->state == MODULE_STATE_COMING)
208 209
		return -EBUSY;
	if (try_module_get(mod))
Linus Torvalds's avatar
Linus Torvalds committed
210
		return 0;
211 212
	else
		return -ENOENT;
Linus Torvalds's avatar
Linus Torvalds committed
213 214
}

215 216
static inline void add_taint_module(struct module *mod, unsigned flag,
				    enum lockdep_ok lockdep_ok)
217
{
218
	add_taint(flag, lockdep_ok);
Andi Kleen's avatar
Andi Kleen committed
219
	mod->taints |= (1U << flag);
220 221
}

222 223 224
/*
 * A thread that wants to hold a reference to a module only while it
 * is running can call this to safely exit.  nfsd and lockd use this.
Linus Torvalds's avatar
Linus Torvalds committed
225 226 227 228 229 230 231
 */
void __module_put_and_exit(struct module *mod, long code)
{
	module_put(mod);
	do_exit(code);
}
EXPORT_SYMBOL(__module_put_and_exit);
232

Linus Torvalds's avatar
Linus Torvalds committed
233
/* Find a module section: 0 means not found. */
234
static unsigned int find_sec(const struct load_info *info, const char *name)
Linus Torvalds's avatar
Linus Torvalds committed
235 236 237
{
	unsigned int i;

238 239
	for (i = 1; i < info->hdr->e_shnum; i++) {
		Elf_Shdr *shdr = &info->sechdrs[i];
Linus Torvalds's avatar
Linus Torvalds committed
240
		/* Alloc bit cleared means "ignore it." */
241 242
		if ((shdr->sh_flags & SHF_ALLOC)
		    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
Linus Torvalds's avatar
Linus Torvalds committed
243
			return i;
244
	}
Linus Torvalds's avatar
Linus Torvalds committed
245 246 247
	return 0;
}

248
/* Find a module section, or NULL. */
249
static void *section_addr(const struct load_info *info, const char *name)
250 251
{
	/* Section 0 has sh_addr 0. */
252
	return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
253 254 255
}

/* Find a module section, or NULL.  Fill in number of "objects" in section. */
256
static void *section_objs(const struct load_info *info,
257 258 259 260
			  const char *name,
			  size_t object_size,
			  unsigned int *num)
{
261
	unsigned int sec = find_sec(info, name);
262 263

	/* Section 0 has sh_addr 0 and sh_size 0. */
264 265
	*num = info->sechdrs[sec].sh_size / object_size;
	return (void *)info->sechdrs[sec].sh_addr;
266 267
}

Linus Torvalds's avatar
Linus Torvalds committed
268 269 270 271 272
/* Provided by the linker */
extern const struct kernel_symbol __start___ksymtab[];
extern const struct kernel_symbol __stop___ksymtab[];
extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
273 274
extern const struct kernel_symbol __start___ksymtab_gpl_future[];
extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
Linus Torvalds's avatar
Linus Torvalds committed
275 276
extern const unsigned long __start___kcrctab[];
extern const unsigned long __start___kcrctab_gpl[];
277
extern const unsigned long __start___kcrctab_gpl_future[];
278 279 280 281 282
#ifdef CONFIG_UNUSED_SYMBOLS
extern const struct kernel_symbol __start___ksymtab_unused[];
extern const struct kernel_symbol __stop___ksymtab_unused[];
extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
283 284
extern const unsigned long __start___kcrctab_unused[];
extern const unsigned long __start___kcrctab_unused_gpl[];
285
#endif
Linus Torvalds's avatar
Linus Torvalds committed
286 287 288 289

#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
#else
290
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
Linus Torvalds's avatar
Linus Torvalds committed
291 292
#endif

293 294 295 296 297
static bool each_symbol_in_section(const struct symsearch *arr,
				   unsigned int arrsize,
				   struct module *owner,
				   bool (*fn)(const struct symsearch *syms,
					      struct module *owner,
298
					      void *data),
299
				   void *data)
300
{
301
	unsigned int j;
302

303
	for (j = 0; j < arrsize; j++) {
304 305
		if (fn(&arr[j], owner, data))
			return true;
306
	}
307 308

	return false;
309 310
}

311
/* Returns true as soon as fn returns true, otherwise false. */
312 313 314 315
bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
				    struct module *owner,
				    void *data),
			 void *data)
316 317
{
	struct module *mod;
318
	static const struct symsearch arr[] = {
319
		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
320
		  NOT_GPL_ONLY, false },
321
		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
322 323
		  __start___kcrctab_gpl,
		  GPL_ONLY, false },
324
		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
325 326
		  __start___kcrctab_gpl_future,
		  WILL_BE_GPL_ONLY, false },
327
#ifdef CONFIG_UNUSED_SYMBOLS
328
		{ __start___ksymtab_unused, __stop___ksymtab_unused,
329 330
		  __start___kcrctab_unused,
		  NOT_GPL_ONLY, true },
331
		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
332 333
		  __start___kcrctab_unused_gpl,
		  GPL_ONLY, true },
334
#endif
335
	};
336

337 338
	module_assert_mutex_or_preempt();

339 340
	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
		return true;
341

342
	list_for_each_entry_rcu(mod, &modules, list) {
343 344
		struct symsearch arr[] = {
			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
345
			  NOT_GPL_ONLY, false },
346
			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
347 348
			  mod->gpl_crcs,
			  GPL_ONLY, false },
349 350
			{ mod->gpl_future_syms,
			  mod->gpl_future_syms + mod->num_gpl_future_syms,
351 352
			  mod->gpl_future_crcs,
			  WILL_BE_GPL_ONLY, false },
353
#ifdef CONFIG_UNUSED_SYMBOLS
354 355
			{ mod->unused_syms,
			  mod->unused_syms + mod->num_unused_syms,
356 357
			  mod->unused_crcs,
			  NOT_GPL_ONLY, true },
358 359
			{ mod->unused_gpl_syms,
			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
360 361
			  mod->unused_gpl_crcs,
			  GPL_ONLY, true },
362
#endif
363 364
		};

365 366 367
		if (mod->state == MODULE_STATE_UNFORMED)
			continue;

368 369 370 371 372
		if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
			return true;
	}
	return false;
}
373
EXPORT_SYMBOL_GPL(each_symbol_section);
374 375 376 377 378 379 380 381 382 383

struct find_symbol_arg {
	/* Input */
	const char *name;
	bool gplok;
	bool warn;

	/* Output */
	struct module *owner;
	const unsigned long *crc;
384
	const struct kernel_symbol *sym;
385 386
};

387 388 389
static bool check_symbol(const struct symsearch *syms,
				 struct module *owner,
				 unsigned int symnum, void *data)
390 391 392 393 394 395 396
{
	struct find_symbol_arg *fsa = data;

	if (!fsa->gplok) {
		if (syms->licence == GPL_ONLY)
			return false;
		if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
397 398 399
			pr_warn("Symbol %s is being used by a non-GPL module, "
				"which will not be allowed in the future\n",
				fsa->name);
400
		}
Linus Torvalds's avatar
Linus Torvalds committed
401
	}
402

403
#ifdef CONFIG_UNUSED_SYMBOLS
404
	if (syms->unused && fsa->warn) {
405 406 407
		pr_warn("Symbol %s is marked as UNUSED, however this module is "
			"using it.\n", fsa->name);
		pr_warn("This symbol will go away in the future.\n");
408 409 410
		pr_warn("Please evaluate if this is the right api to use and "
			"if it really is, submit a report to the linux kernel "
			"mailing list together with submitting your code for "
411
			"inclusion.\n");
412
	}
413
#endif
414 415 416

	fsa->owner = owner;
	fsa->crc = symversion(syms->crcs, symnum);
417
	fsa->sym = &syms->start[symnum];
418 419 420
	return true;
}

421 422 423 424 425 426 427 428
static int cmp_name(const void *va, const void *vb)
{
	const char *a;
	const struct kernel_symbol *b;
	a = va; b = vb;
	return strcmp(a, b->name);
}

429 430 431 432 433
static bool find_symbol_in_section(const struct symsearch *syms,
				   struct module *owner,
				   void *data)
{
	struct find_symbol_arg *fsa = data;
434 435 436 437 438 439 440
	struct kernel_symbol *sym;

	sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
			sizeof(struct kernel_symbol), cmp_name);

	if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
		return true;
441 442 443 444

	return false;
}

445
/* Find a symbol and return it, along with, (optional) crc and
446
 * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
447 448 449 450 451
const struct kernel_symbol *find_symbol(const char *name,
					struct module **owner,
					const unsigned long **crc,
					bool gplok,
					bool warn)
452 453 454 455 456 457 458
{
	struct find_symbol_arg fsa;

	fsa.name = name;
	fsa.gplok = gplok;
	fsa.warn = warn;

459
	if (each_symbol_section(find_symbol_in_section, &fsa)) {
460 461 462 463
		if (owner)
			*owner = fsa.owner;
		if (crc)
			*crc = fsa.crc;
464
		return fsa.sym;
465 466
	}

467
	pr_debug("Failed to find symbol %s\n", name);
468
	return NULL;
Linus Torvalds's avatar
Linus Torvalds committed
469
}
470
EXPORT_SYMBOL_GPL(find_symbol);
Linus Torvalds's avatar
Linus Torvalds committed
471 472

/* Search for module by name: must hold module_mutex. */
473
static struct module *find_module_all(const char *name, size_t len,
474
				      bool even_unformed)
Linus Torvalds's avatar
Linus Torvalds committed
475 476 477
{
	struct module *mod;

478 479
	module_assert_mutex();

Linus Torvalds's avatar
Linus Torvalds committed
480
	list_for_each_entry(mod, &modules, list) {
481 482
		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
			continue;
483
		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
Linus Torvalds's avatar
Linus Torvalds committed
484 485 486 487
			return mod;
	}
	return NULL;
}
488 489 490

struct module *find_module(const char *name)
{
491
	return find_module_all(name, strlen(name), false);
492
}
493
EXPORT_SYMBOL_GPL(find_module);
Linus Torvalds's avatar
Linus Torvalds committed
494 495

#ifdef CONFIG_SMP
496

497
static inline void __percpu *mod_percpu(struct module *mod)
498
{
499 500
	return mod->percpu;
}
501

Rusty Russell's avatar
Rusty Russell committed
502
static int percpu_modalloc(struct module *mod, struct load_info *info)
503
{
Rusty Russell's avatar
Rusty Russell committed
504 505 506 507 508 509
	Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
	unsigned long align = pcpusec->sh_addralign;

	if (!pcpusec->sh_size)
		return 0;

510
	if (align > PAGE_SIZE) {
511 512
		pr_warn("%s: per-cpu alignment %li > %li\n",
			mod->name, align, PAGE_SIZE);
513 514 515
		align = PAGE_SIZE;
	}

Rusty Russell's avatar
Rusty Russell committed
516
	mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
517
	if (!mod->percpu) {
518 519
		pr_warn("%s: Could not allocate %lu bytes percpu data\n",
			mod->name, (unsigned long)pcpusec->sh_size);
520 521
		return -ENOMEM;
	}
Rusty Russell's avatar
Rusty Russell committed
522
	mod->percpu_size = pcpusec->sh_size;
523
	return 0;
524 525
}

526
static void percpu_modfree(struct module *mod)
527
{
528
	free_percpu(mod->percpu);
529 530
}

531
static unsigned int find_pcpusec(struct load_info *info)
532
{
533
	return find_sec(info, ".data..percpu");
534 535
}

536 537
static void percpu_modcopy(struct module *mod,
			   const void *from, unsigned long size)
538 539 540 541
{
	int cpu;

	for_each_possible_cpu(cpu)
542
		memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
543 544
}

545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561
/**
 * is_module_percpu_address - test whether address is from module static percpu
 * @addr: address to test
 *
 * Test whether @addr belongs to module static percpu area.
 *
 * RETURNS:
 * %true if @addr is from module static percpu area
 */
bool is_module_percpu_address(unsigned long addr)
{
	struct module *mod;
	unsigned int cpu;

	preempt_disable();

	list_for_each_entry_rcu(mod, &modules, list) {
562 563
		if (mod->state == MODULE_STATE_UNFORMED)
			continue;
564 565 566 567 568 569 570 571 572 573 574 575 576 577 578
		if (!mod->percpu_size)
			continue;
		for_each_possible_cpu(cpu) {
			void *start = per_cpu_ptr(mod->percpu, cpu);

			if ((void *)addr >= start &&
			    (void *)addr < start + mod->percpu_size) {
				preempt_enable();
				return true;
			}
		}
	}

	preempt_enable();
	return false;
579 580
}

Linus Torvalds's avatar
Linus Torvalds committed
581
#else /* ... !CONFIG_SMP */
582

583
static inline void __percpu *mod_percpu(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
584 585 586
{
	return NULL;
}
Rusty Russell's avatar
Rusty Russell committed
587
static int percpu_modalloc(struct module *mod, struct load_info *info)
588
{
Rusty Russell's avatar
Rusty Russell committed
589 590 591 592
	/* UP modules shouldn't have this section: ENOMEM isn't quite right */
	if (info->sechdrs[info->index.pcpu].sh_size != 0)
		return -ENOMEM;
	return 0;
593 594
}
static inline void percpu_modfree(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
595 596
{
}
597
static unsigned int find_pcpusec(struct load_info *info)
Linus Torvalds's avatar
Linus Torvalds committed
598 599 600
{
	return 0;
}
601 602
static inline void percpu_modcopy(struct module *mod,
				  const void *from, unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
603 604 605 606
{
	/* pcpusec should be 0, and size of that section should be 0. */
	BUG_ON(size != 0);
}
607 608 609 610
bool is_module_percpu_address(unsigned long addr)
{
	return false;
}
611

Linus Torvalds's avatar
Linus Torvalds committed
612 613
#endif /* CONFIG_SMP */

614 615 616 617 618 619
#define MODINFO_ATTR(field)	\
static void setup_modinfo_##field(struct module *mod, const char *s)  \
{                                                                     \
	mod->field = kstrdup(s, GFP_KERNEL);                          \
}                                                                     \
static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
620
			struct module_kobject *mk, char *buffer)      \
621
{                                                                     \
622
	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
623 624 625 626 627 628 629
}                                                                     \
static int modinfo_##field##_exists(struct module *mod)               \
{                                                                     \
	return mod->field != NULL;                                    \
}                                                                     \
static void free_modinfo_##field(struct module *mod)                  \
{                                                                     \
630 631
	kfree(mod->field);                                            \
	mod->field = NULL;                                            \
632 633
}                                                                     \
static struct module_attribute modinfo_##field = {                    \
634
	.attr = { .name = __stringify(field), .mode = 0444 },         \
635 636 637 638 639 640 641 642 643
	.show = show_modinfo_##field,                                 \
	.setup = setup_modinfo_##field,                               \
	.test = modinfo_##field##_exists,                             \
	.free = free_modinfo_##field,                                 \
};

MODINFO_ATTR(version);
MODINFO_ATTR(srcversion);

644 645
static char last_unloaded_module[MODULE_NAME_LEN+1];

646
#ifdef CONFIG_MODULE_UNLOAD
647 648 649

EXPORT_TRACEPOINT_SYMBOL(module_get);

650 651 652
/* MODULE_REF_BASE is the base reference count by kmodule loader. */
#define MODULE_REF_BASE	1

Linus Torvalds's avatar
Linus Torvalds committed
653
/* Init the unload section of the module. */
654
static int module_unload_init(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
655
{
656 657 658 659 660
	/*
	 * Initialize reference counter to MODULE_REF_BASE.
	 * refcnt == 0 means module is going.
	 */
	atomic_set(&mod->refcnt, MODULE_REF_BASE);
661

662 663
	INIT_LIST_HEAD(&mod->source_list);
	INIT_LIST_HEAD(&mod->target_list);
664

Linus Torvalds's avatar
Linus Torvalds committed
665
	/* Hold reference count during initialization. */
666
	atomic_inc(&mod->refcnt);
667 668

	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
669 670 671 672 673 674 675
}

/* Does a already use b? */
static int already_uses(struct module *a, struct module *b)
{
	struct module_use *use;

676 677
	list_for_each_entry(use, &b->source_list, source_list) {
		if (use->source == a) {
678
			pr_debug("%s uses %s!\n", a->name, b->name);
Linus Torvalds's avatar
Linus Torvalds committed
679 680 681
			return 1;
		}
	}
682
	pr_debug("%s does not use %s!\n", a->name, b->name);
Linus Torvalds's avatar
Linus Torvalds committed
683 684 685
	return 0;
}

686 687 688 689 690 691 692 693 694 695 696
/*
 * Module a uses b
 *  - we add 'a' as a "source", 'b' as a "target" of module use
 *  - the module_use is added to the list of 'b' sources (so
 *    'b' can walk the list to see who sourced them), and of 'a'
 *    targets (so 'a' can see what modules it targets).
 */
static int add_module_usage(struct module *a, struct module *b)
{
	struct module_use *use;

697
	pr_debug("Allocating new usage for %s.\n", a->name);
698 699
	use = kmalloc(sizeof(*use), GFP_ATOMIC);
	if (!use) {
700
		pr_warn("%s: out of memory loading\n", a->name);
701 702 703 704 705 706 707 708 709 710
		return -ENOMEM;
	}

	use->source = a;
	use->target = b;
	list_add(&use->source_list, &b->source_list);
	list_add(&use->target_list, &a->target_list);
	return 0;
}

711
/* Module a uses b: caller needs module_mutex() */
712
int ref_module(struct module *a, struct module *b)
Linus Torvalds's avatar
Linus Torvalds committed
713
{
714
	int err;
Kay Sievers's avatar
Kay Sievers committed
715

716
	if (b == NULL || already_uses(a, b))
717 718
		return 0;

719 720
	/* If module isn't available, we fail. */
	err = strong_try_module_get(b);
721
	if (err)
722
		return err;
Linus Torvalds's avatar
Linus Torvalds committed
723

724 725
	err = add_module_usage(a, b);
	if (err) {
Linus Torvalds's avatar
Linus Torvalds committed
726
		module_put(b);
727
		return err;
Linus Torvalds's avatar
Linus Torvalds committed
728
	}
729
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
730
}
731
EXPORT_SYMBOL_GPL(ref_module);
Linus Torvalds's avatar
Linus Torvalds committed
732 733 734 735

/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
736
	struct module_use *use, *tmp;
Linus Torvalds's avatar
Linus Torvalds committed
737

738
	mutex_lock(&module_mutex);
739 740
	list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
		struct module *i = use->target;
741
		pr_debug("%s unusing %s\n", mod->name, i->name);
742 743 744 745
		module_put(i);
		list_del(&use->source_list);
		list_del(&use->target_list);
		kfree(use);
Linus Torvalds's avatar
Linus Torvalds committed
746
	}
747
	mutex_unlock(&module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
748 749 750
}

#ifdef CONFIG_MODULE_FORCE_UNLOAD
751
static inline int try_force_unload(unsigned int flags)
Linus Torvalds's avatar
Linus Torvalds committed
752 753 754
{
	int ret = (flags & O_TRUNC);
	if (ret)
755
		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
Linus Torvalds's avatar
Linus Torvalds committed
756 757 758
	return ret;
}
#else
759
static inline int try_force_unload(unsigned int flags)
Linus Torvalds's avatar
Linus Torvalds committed
760 761 762 763 764
{
	return 0;
}
#endif /* CONFIG_MODULE_FORCE_UNLOAD */

765 766
/* Try to release refcount of module, 0 means success. */
static int try_release_module_ref(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
767
{
768
	int ret;
Linus Torvalds's avatar
Linus Torvalds committed
769

770 771 772 773 774 775
	/* Try to decrement refcnt which we set at loading */
	ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt);
	BUG_ON(ret < 0);
	if (ret)
		/* Someone can put this right now, recover with checking */
		ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0);
Linus Torvalds's avatar
Linus Torvalds committed
776

777 778
	return ret;
}
Linus Torvalds's avatar
Linus Torvalds committed
779

780 781
static int try_stop_module(struct module *mod, int flags, int *forced)
{
782
	/* If it's not unused, quit unless we're forcing. */
783 784 785
	if (try_release_module_ref(mod) != 0) {
		*forced = try_force_unload(flags);
		if (!(*forced))
Linus Torvalds's avatar
Linus Torvalds committed
786 787 788 789
			return -EWOULDBLOCK;
	}

	/* Mark it as dying. */
790
	mod->state = MODULE_STATE_GOING;
Linus Torvalds's avatar
Linus Torvalds committed
791

792
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
793 794
}

795 796 797 798 799 800 801 802 803 804
/**
 * module_refcount - return the refcount or -1 if unloading
 *
 * @mod:	the module we're checking
 *
 * Returns:
 *	-1 if the module is in the process of unloading
 *	otherwise the number of references in the kernel to the module
 */
int module_refcount(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
805
{
806
	return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
Linus Torvalds's avatar
Linus Torvalds committed
807 808 809 810 811 812
}
EXPORT_SYMBOL(module_refcount);

/* This exists whether we can unload or not */
static void free_module(struct module *mod);

813 814
SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
		unsigned int, flags)
Linus Torvalds's avatar
Linus Torvalds committed
815 816
{
	struct module *mod;
817
	char name[MODULE_NAME_LEN];
Linus Torvalds's avatar
Linus Torvalds committed
818 819
	int ret, forced = 0;

820
	if (!capable(CAP_SYS_MODULE) || modules_disabled)
821 822 823 824 825 826
		return -EPERM;

	if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
		return -EFAULT;
	name[MODULE_NAME_LEN-1] = '\0';

827 828
	if (mutex_lock_interruptible(&module_mutex) != 0)
		return -EINTR;
Linus Torvalds's avatar
Linus Torvalds committed
829 830 831 832 833 834 835

	mod = find_module(name);
	if (!mod) {
		ret = -ENOENT;
		goto out;
	}

836
	if (!list_empty(&mod->source_list)) {
Linus Torvalds's avatar
Linus Torvalds committed
837 838 839 840 841 842 843
		/* Other modules depend on us: get rid of them first. */
		ret = -EWOULDBLOCK;
		goto out;
	}

	/* Doing init or already dying? */
	if (mod->state != MODULE_STATE_LIVE) {
844
		/* FIXME: if (force), slam module count damn the torpedoes */
845
		pr_debug("%s already dying\n", mod->name);
Linus Torvalds's avatar
Linus Torvalds committed
846 847 848 849 850
		ret = -EBUSY;
		goto out;
	}

	/* If it has an init func, it must have an exit func to unload */
851
	if (mod->init && !mod->exit) {
852
		forced = try_force_unload(flags);
Linus Torvalds's avatar
Linus Torvalds committed
853 854 855 856 857 858 859 860 861 862 863 864
		if (!forced) {
			/* This module can't be removed */
			ret = -EBUSY;
			goto out;
		}
	}

	/* Stop the machine so refcounts can't move and disable module. */
	ret = try_stop_module(mod, flags, &forced);
	if (ret != 0)
		goto out;

865
	mutex_unlock(&module_mutex);
Lucas De Marchi's avatar
Lucas De Marchi committed
866
	/* Final destruction now no one is using it. */
867
	if (mod->exit != NULL)
Linus Torvalds's avatar
Linus Torvalds committed
868
		mod->exit();
869 870
	blocking_notifier_call_chain(&module_notify_list,
				     MODULE_STATE_GOING, mod);
871
	async_synchronize_full();
872

873
	/* Store the name of the last unloaded module for diagnostic purposes */
874
	strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
Linus Torvalds's avatar
Linus Torvalds committed
875

876 877 878
	free_module(mod);
	return 0;
out:
879
	mutex_unlock(&module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
880 881 882
	return ret;
}

883
static inline void print_unload_info(struct seq_file *m, struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
884 885 886 887
{
	struct module_use *use;
	int printed_something = 0;

888
	seq_printf(m, " %i ", module_refcount(mod));
Linus Torvalds's avatar
Linus Torvalds committed
889

890 891 892 893
	/*
	 * Always include a trailing , so userspace can differentiate
	 * between this and the old multi-field proc format.
	 */
894
	list_for_each_entry(use, &mod->source_list, source_list) {
Linus Torvalds's avatar
Linus Torvalds committed
895
		printed_something = 1;
896
		seq_printf(m, "%s,", use->source->name);
Linus Torvalds's avatar
Linus Torvalds committed
897 898 899 900
	}

	if (mod->init != NULL && mod->exit == NULL) {
		printed_something = 1;
901
		seq_puts(m, "[permanent],");
Linus Torvalds's avatar
Linus Torvalds committed
902 903 904
	}

	if (!printed_something)
905
		seq_puts(m, "-");
Linus Torvalds's avatar
Linus Torvalds committed
906 907 908 909 910 911
}

void __symbol_put(const char *symbol)
{
	struct module *owner;

Rusty Russell's avatar
Rusty Russell committed
912
	preempt_disable();
913
	if (!find_symbol(symbol, &owner, NULL, true, false))
Linus Torvalds's avatar
Linus Torvalds committed
914 915
		BUG();
	module_put(owner);
Rusty Russell's avatar
Rusty Russell committed
916
	preempt_enable();
Linus Torvalds's avatar
Linus Torvalds committed
917 918 919
}
EXPORT_SYMBOL(__symbol_put);

920
/* Note this assumes addr is a function, which it currently always is. */
Linus Torvalds's avatar
Linus Torvalds committed
921 922
void symbol_put_addr(void *addr)
{
923
	struct module *modaddr;
924
	unsigned long a = (unsigned long)dereference_function_descriptor(addr);
Linus Torvalds's avatar
Linus Torvalds committed
925

926
	if (core_kernel_text(a))
927
		return;
Linus Torvalds's avatar
Linus Torvalds committed
928

929 930
	/* module_text_address is safe here: we're supposed to have reference
	 * to module from symbol_get, so it can't go away. */
931
	modaddr = __module_text_address(a);
932
	BUG_ON(!modaddr);
933
	module_put(modaddr);
Linus Torvalds's avatar
Linus Torvalds committed
934 935 936 937
}
EXPORT_SYMBOL_GPL(symbol_put_addr);

static ssize_t show_refcnt(struct module_attribute *mattr,
938
			   struct module_kobject *mk, char *buffer)
Linus Torvalds's avatar
Linus Torvalds committed
939
{
940
	return sprintf(buffer, "%i\n", module_refcount(mk->mod));
Linus Torvalds's avatar
Linus Torvalds committed
941 942
}

943 944
static struct module_attribute modinfo_refcnt =
	__ATTR(refcnt, 0444, show_refcnt, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
945

946 947 948 949
void __module_get(struct module *module)
{
	if (module) {
		preempt_disable();
950
		atomic_inc(&module->refcnt);
951 952 953 954 955 956 957 958 959 960 961 962
		trace_module_get(module, _RET_IP_);
		preempt_enable();
	}
}
EXPORT_SYMBOL(__module_get);

bool try_module_get(struct module *module)
{
	bool ret = true;

	if (module) {
		preempt_disable();
963 964 965
		/* Note: here, we can fail to get a reference */
		if (likely(module_is_live(module) &&
			   atomic_inc_not_zero(&module->refcnt) != 0))
966
			trace_module_get(module, _RET_IP_);
967
		else
968 969 970 971 972 973 974 975
			ret = false;

		preempt_enable();
	}
	return ret;
}
EXPORT_SYMBOL(try_module_get);

Al Viro's avatar
Al Viro committed
976 977
void module_put(struct module *module)
{
978 979
	int ret;

Al Viro's avatar
Al Viro committed
980
	if (module) {
981
		preempt_disable();
982 983
		ret = atomic_dec_if_positive(&module->refcnt);
		WARN_ON(ret < 0);	/* Failed to put refcount */
984
		trace_module_put(module, _RET_IP_);
985
		preempt_enable();
Al Viro's avatar
Al Viro committed
986 987 988 989
	}
}
EXPORT_SYMBOL(module_put);

Linus Torvalds's avatar
Linus Torvalds committed
990
#else /* !CONFIG_MODULE_UNLOAD */
991
static inline void print_unload_info(struct seq_file *m, struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
992 993
{
	/* We don't know the usage count, or what modules are using. */
994
	seq_puts(m, " - -");
Linus Torvalds's avatar
Linus Torvalds committed
995 996 997 998 999 1000
}

static inline void module_unload_free(struct module *mod)
{
}

1001
int ref_module(struct module *a, struct module *b)
Linus Torvalds's avatar
Linus Torvalds committed
1002
{
1003
	return strong_try_module_get(b);
Linus Torvalds's avatar
Linus Torvalds committed
1004
}
1005
EXPORT_SYMBOL_GPL(ref_module);
Linus Torvalds's avatar
Linus Torvalds committed
1006

1007
static inline int module_unload_init(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
1008
{
1009
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
1010 1011 1012
}
#endif /* CONFIG_MODULE_UNLOAD */

1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024
static size_t module_flags_taint(struct module *mod, char *buf)
{
	size_t l = 0;

	if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
		buf[l++] = 'P';
	if (mod->taints & (1 << TAINT_OOT_MODULE))
		buf[l++] = 'O';
	if (mod->taints & (1 << TAINT_FORCED_MODULE))
		buf[l++] = 'F';
	if (mod->taints & (1 << TAINT_CRAP))
		buf[l++] = 'C';
1025
	if (mod->taints & (1 << TAINT_UNSIGNED_MODULE))
1026
		buf[l++] = 'E';
1027 1028
	/*
	 * TAINT_FORCED_RMMOD: could be added.
1029
	 * TAINT_CPU_OUT_OF_SPEC, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
1030 1031 1032 1033 1034
	 * apply to modules.
	 */
	return l;
}

1035
static ssize_t show_initstate(struct module_attribute *mattr,
1036
			      struct module_kobject *mk, char *buffer)
1037 1038 1039
{
	const char *state = "unknown";

1040
	switch (mk->mod->state) {
1041 1042 1043 1044 1045 1046 1047 1048 1049
	case MODULE_STATE_LIVE:
		state = "live";
		break;
	case MODULE_STATE_COMING:
		state = "coming";
		break;
	case MODULE_STATE_GOING:
		state = "going";
		break;
1050 1051
	default:
		BUG();
1052 1053 1054 1055
	}
	return sprintf(buffer, "%s\n", state);
}

1056 1057
static struct module_attribute modinfo_initstate =
	__ATTR(initstate, 0444, show_initstate, NULL);
1058

1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
static ssize_t store_uevent(struct module_attribute *mattr,
			    struct module_kobject *mk,
			    const char *buffer, size_t count)
{
	enum kobject_action action;

	if (kobject_action_type(buffer, count, &action) == 0)
		kobject_uevent(&mk->kobj, action);
	return count;
}

1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102
struct module_attribute module_uevent =
	__ATTR(uevent, 0200, NULL, store_uevent);

static ssize_t show_coresize(struct module_attribute *mattr,
			     struct module_kobject *mk, char *buffer)
{
	return sprintf(buffer, "%u\n", mk->mod->core_size);
}

static struct module_attribute modinfo_coresize =
	__ATTR(coresize, 0444, show_coresize, NULL);

static ssize_t show_initsize(struct module_attribute *mattr,
			     struct module_kobject *mk, char *buffer)
{
	return sprintf(buffer, "%u\n", mk->mod->init_size);
}

static struct module_attribute modinfo_initsize =
	__ATTR(initsize, 0444, show_initsize, NULL);

static ssize_t show_taint(struct module_attribute *mattr,
			  struct module_kobject *mk, char *buffer)
{
	size_t l;

	l = module_flags_taint(mk->mod, buffer);
	buffer[l++] = '\n';
	return l;
}

static struct module_attribute modinfo_taint =
	__ATTR(taint, 0444, show_taint, NULL);
1103

1104
static struct module_attribute *modinfo_attrs[] = {
1105
	&module_uevent,
1106 1107
	&modinfo_version,
	&modinfo_srcversion,
1108 1109 1110 1111
	&modinfo_initstate,
	&modinfo_coresize,
	&modinfo_initsize,
	&modinfo_taint,
1112
#ifdef CONFIG_MODULE_UNLOAD
1113
	&modinfo_refcnt,
1114 1115 1116 1117
#endif
	NULL,
};

Linus Torvalds's avatar
Linus Torvalds committed
1118 1119
static const char vermagic[] = VERMAGIC_STRING;

1120
static int try_to_force_load(struct module *mod, const char *reason)
1121 1122
{
#ifdef CONFIG_MODULE_FORCE_LOAD
Andi Kleen's avatar
Andi Kleen committed
1123
	if (!test_taint(TAINT_FORCED_MODULE))
1124
		pr_warn("%s: %s: kernel tainted.\n", mod->name, reason);
1125
	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
1126 1127 1128 1129 1130 1131
	return 0;
#else
	return -ENOEXEC;
#endif
}

Linus Torvalds's avatar
Linus Torvalds committed
1132
#ifdef CONFIG_MODVERSIONS
1133 1134 1135 1136 1137 1138 1139 1140 1141