module.c 102 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
#ifdef CONFIG_MODULES_TREE_LOOKUP

107 108 109 110 111 112 113 114 115 116
/*
 * Use a latched RB-tree for __module_address(); this allows us to use
 * RCU-sched lookups of the address from any context.
 *
 * Because modules have two address ranges: init and core, we need two
 * latch_tree_nodes entries. Therefore we need the back-pointer from
 * mod_tree_node.
 *
 * Because init ranges are short lived we mark them unlikely and have placed
 * them outside the critical cacheline in struct module.
117 118 119 120
 *
 * This is conditional on PERF_EVENTS || TRACING because those can really hit
 * __module_address() hard by doing a lot of stack unwinding; potentially from
 * NMI context.
121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200
 */

static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
{
	struct mod_tree_node *mtn = container_of(n, struct mod_tree_node, node);
	struct module *mod = mtn->mod;

	if (unlikely(mtn == &mod->mtn_init))
		return (unsigned long)mod->module_init;

	return (unsigned long)mod->module_core;
}

static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
{
	struct mod_tree_node *mtn = container_of(n, struct mod_tree_node, node);
	struct module *mod = mtn->mod;

	if (unlikely(mtn == &mod->mtn_init))
		return (unsigned long)mod->init_size;

	return (unsigned long)mod->core_size;
}

static __always_inline bool
mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
{
	return __mod_tree_val(a) < __mod_tree_val(b);
}

static __always_inline int
mod_tree_comp(void *key, struct latch_tree_node *n)
{
	unsigned long val = (unsigned long)key;
	unsigned long start, end;

	start = __mod_tree_val(n);
	if (val < start)
		return -1;

	end = start + __mod_tree_size(n);
	if (val >= end)
		return 1;

	return 0;
}

static const struct latch_tree_ops mod_tree_ops = {
	.less = mod_tree_less,
	.comp = mod_tree_comp,
};

static struct latch_tree_root mod_tree __cacheline_aligned;

/*
 * These modifications: insert, remove_init and remove; are serialized by the
 * module_mutex.
 */
static void mod_tree_insert(struct module *mod)
{
	mod->mtn_core.mod = mod;
	mod->mtn_init.mod = mod;

	latch_tree_insert(&mod->mtn_core.node, &mod_tree, &mod_tree_ops);
	if (mod->init_size)
		latch_tree_insert(&mod->mtn_init.node, &mod_tree, &mod_tree_ops);
}

static void mod_tree_remove_init(struct module *mod)
{
	if (mod->init_size)
		latch_tree_erase(&mod->mtn_init.node, &mod_tree, &mod_tree_ops);
}

static void mod_tree_remove(struct module *mod)
{
	latch_tree_erase(&mod->mtn_core.node, &mod_tree, &mod_tree_ops);
	mod_tree_remove_init(mod);
}

201
static struct module *mod_find(unsigned long addr)
202 203 204 205 206 207 208 209 210 211
{
	struct latch_tree_node *ltn;

	ltn = latch_tree_find((void *)addr, &mod_tree, &mod_tree_ops);
	if (!ltn)
		return NULL;

	return container_of(ltn, struct mod_tree_node, node)->mod;
}

212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231
#else /* MODULES_TREE_LOOKUP */

static void mod_tree_insert(struct module *mod) { }
static void mod_tree_remove_init(struct module *mod) { }
static void mod_tree_remove(struct module *mod) { }

static struct module *mod_find(unsigned long addr)
{
	struct module *mod;

	list_for_each_entry_rcu(mod, &modules, list) {
		if (within_module(addr, mod))
			return mod;
	}

	return NULL;
}

#endif /* MODULES_TREE_LOOKUP */

232 233 234 235
#ifdef CONFIG_KGDB_KDB
struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
#endif /* CONFIG_KGDB_KDB */

236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251
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
}

252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280
#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 = {
281
	.flags = KERNEL_PARAM_OPS_FL_NOARG,
282 283 284 285 286 287 288 289
	.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
290

291 292
/* Block module loading/unloading? */
int modules_disabled = 0;
293
core_param(nomodule, modules_disabled, bint, 0);
294

295 296 297
/* Waiting for a module to finish initializing? */
static DECLARE_WAIT_QUEUE_HEAD(module_wq);

298
static BLOCKING_NOTIFIER_HEAD(module_notify_list);
Linus Torvalds's avatar
Linus Torvalds committed
299

300 301
/* Bounds of module allocation, for speeding __module_address.
 * Protected by module_mutex. */
302 303
static unsigned long module_addr_min = -1UL, module_addr_max = 0;

304
int register_module_notifier(struct notifier_block *nb)
Linus Torvalds's avatar
Linus Torvalds committed
305
{
306
	return blocking_notifier_chain_register(&module_notify_list, nb);
Linus Torvalds's avatar
Linus Torvalds committed
307 308 309
}
EXPORT_SYMBOL(register_module_notifier);

310
int unregister_module_notifier(struct notifier_block *nb)
Linus Torvalds's avatar
Linus Torvalds committed
311
{
312
	return blocking_notifier_chain_unregister(&module_notify_list, nb);
Linus Torvalds's avatar
Linus Torvalds committed
313 314 315
}
EXPORT_SYMBOL(unregister_module_notifier);

316 317 318 319
struct load_info {
	Elf_Ehdr *hdr;
	unsigned long len;
	Elf_Shdr *sechdrs;
320
	char *secstrings, *strtab;
Rusty Russell's avatar
Rusty Russell committed
321
	unsigned long symoffs, stroffs;
322 323
	struct _ddebug *debug;
	unsigned int num_debug;
324
	bool sig_ok;
325 326 327 328 329
	struct {
		unsigned int sym, str, mod, vers, info, pcpu;
	} index;
};

330 331
/* 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
332 333
static inline int strong_try_module_get(struct module *mod)
{
334
	BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
Linus Torvalds's avatar
Linus Torvalds committed
335
	if (mod && mod->state == MODULE_STATE_COMING)
336 337
		return -EBUSY;
	if (try_module_get(mod))
Linus Torvalds's avatar
Linus Torvalds committed
338
		return 0;
339 340
	else
		return -ENOENT;
Linus Torvalds's avatar
Linus Torvalds committed
341 342
}

343 344
static inline void add_taint_module(struct module *mod, unsigned flag,
				    enum lockdep_ok lockdep_ok)
345
{
346
	add_taint(flag, lockdep_ok);
Andi Kleen's avatar
Andi Kleen committed
347
	mod->taints |= (1U << flag);
348 349
}

350 351 352
/*
 * 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
353 354 355 356 357 358 359
 */
void __module_put_and_exit(struct module *mod, long code)
{
	module_put(mod);
	do_exit(code);
}
EXPORT_SYMBOL(__module_put_and_exit);
360

Linus Torvalds's avatar
Linus Torvalds committed
361
/* Find a module section: 0 means not found. */
362
static unsigned int find_sec(const struct load_info *info, const char *name)
Linus Torvalds's avatar
Linus Torvalds committed
363 364 365
{
	unsigned int i;

366 367
	for (i = 1; i < info->hdr->e_shnum; i++) {
		Elf_Shdr *shdr = &info->sechdrs[i];
Linus Torvalds's avatar
Linus Torvalds committed
368
		/* Alloc bit cleared means "ignore it." */
369 370
		if ((shdr->sh_flags & SHF_ALLOC)
		    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
Linus Torvalds's avatar
Linus Torvalds committed
371
			return i;
372
	}
Linus Torvalds's avatar
Linus Torvalds committed
373 374 375
	return 0;
}

376
/* Find a module section, or NULL. */
377
static void *section_addr(const struct load_info *info, const char *name)
378 379
{
	/* Section 0 has sh_addr 0. */
380
	return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
381 382 383
}

/* Find a module section, or NULL.  Fill in number of "objects" in section. */
384
static void *section_objs(const struct load_info *info,
385 386 387 388
			  const char *name,
			  size_t object_size,
			  unsigned int *num)
{
389
	unsigned int sec = find_sec(info, name);
390 391

	/* Section 0 has sh_addr 0 and sh_size 0. */
392 393
	*num = info->sechdrs[sec].sh_size / object_size;
	return (void *)info->sechdrs[sec].sh_addr;
394 395
}

Linus Torvalds's avatar
Linus Torvalds committed
396 397 398 399 400
/* 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[];
401 402
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
403 404
extern const unsigned long __start___kcrctab[];
extern const unsigned long __start___kcrctab_gpl[];
405
extern const unsigned long __start___kcrctab_gpl_future[];
406 407 408 409 410
#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[];
411 412
extern const unsigned long __start___kcrctab_unused[];
extern const unsigned long __start___kcrctab_unused_gpl[];
413
#endif
Linus Torvalds's avatar
Linus Torvalds committed
414 415 416 417

#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
#else
418
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
Linus Torvalds's avatar
Linus Torvalds committed
419 420
#endif

421 422 423 424 425
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,
426
					      void *data),
427
				   void *data)
428
{
429
	unsigned int j;
430

431
	for (j = 0; j < arrsize; j++) {
432 433
		if (fn(&arr[j], owner, data))
			return true;
434
	}
435 436

	return false;
437 438
}

439
/* Returns true as soon as fn returns true, otherwise false. */
440 441 442 443
bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
				    struct module *owner,
				    void *data),
			 void *data)
444 445
{
	struct module *mod;
446
	static const struct symsearch arr[] = {
447
		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
448
		  NOT_GPL_ONLY, false },
449
		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
450 451
		  __start___kcrctab_gpl,
		  GPL_ONLY, false },
452
		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
453 454
		  __start___kcrctab_gpl_future,
		  WILL_BE_GPL_ONLY, false },
455
#ifdef CONFIG_UNUSED_SYMBOLS
456
		{ __start___ksymtab_unused, __stop___ksymtab_unused,
457 458
		  __start___kcrctab_unused,
		  NOT_GPL_ONLY, true },
459
		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
460 461
		  __start___kcrctab_unused_gpl,
		  GPL_ONLY, true },
462
#endif
463
	};
464

465 466
	module_assert_mutex_or_preempt();

467 468
	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
		return true;
469

470
	list_for_each_entry_rcu(mod, &modules, list) {
471 472
		struct symsearch arr[] = {
			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
473
			  NOT_GPL_ONLY, false },
474
			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
475 476
			  mod->gpl_crcs,
			  GPL_ONLY, false },
477 478
			{ mod->gpl_future_syms,
			  mod->gpl_future_syms + mod->num_gpl_future_syms,
479 480
			  mod->gpl_future_crcs,
			  WILL_BE_GPL_ONLY, false },
481
#ifdef CONFIG_UNUSED_SYMBOLS
482 483
			{ mod->unused_syms,
			  mod->unused_syms + mod->num_unused_syms,
484 485
			  mod->unused_crcs,
			  NOT_GPL_ONLY, true },
486 487
			{ mod->unused_gpl_syms,
			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
488 489
			  mod->unused_gpl_crcs,
			  GPL_ONLY, true },
490
#endif
491 492
		};

493 494 495
		if (mod->state == MODULE_STATE_UNFORMED)
			continue;

496 497 498 499 500
		if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
			return true;
	}
	return false;
}
501
EXPORT_SYMBOL_GPL(each_symbol_section);
502 503 504 505 506 507 508 509 510 511

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

	/* Output */
	struct module *owner;
	const unsigned long *crc;
512
	const struct kernel_symbol *sym;
513 514
};

515 516 517
static bool check_symbol(const struct symsearch *syms,
				 struct module *owner,
				 unsigned int symnum, void *data)
518 519 520 521 522 523 524
{
	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) {
525 526 527
			pr_warn("Symbol %s is being used by a non-GPL module, "
				"which will not be allowed in the future\n",
				fsa->name);
528
		}
Linus Torvalds's avatar
Linus Torvalds committed
529
	}
530

531
#ifdef CONFIG_UNUSED_SYMBOLS
532
	if (syms->unused && fsa->warn) {
533 534 535
		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");
536 537 538
		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 "
539
			"inclusion.\n");
540
	}
541
#endif
542 543 544

	fsa->owner = owner;
	fsa->crc = symversion(syms->crcs, symnum);
545
	fsa->sym = &syms->start[symnum];
546 547 548
	return true;
}

549 550 551 552 553 554 555 556
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);
}

557 558 559 560 561
static bool find_symbol_in_section(const struct symsearch *syms,
				   struct module *owner,
				   void *data)
{
	struct find_symbol_arg *fsa = data;
562 563 564 565 566 567 568
	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;
569 570 571 572

	return false;
}

573
/* Find a symbol and return it, along with, (optional) crc and
574
 * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
575 576 577 578 579
const struct kernel_symbol *find_symbol(const char *name,
					struct module **owner,
					const unsigned long **crc,
					bool gplok,
					bool warn)
580 581 582 583 584 585 586
{
	struct find_symbol_arg fsa;

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

587
	if (each_symbol_section(find_symbol_in_section, &fsa)) {
588 589 590 591
		if (owner)
			*owner = fsa.owner;
		if (crc)
			*crc = fsa.crc;
592
		return fsa.sym;
593 594
	}

595
	pr_debug("Failed to find symbol %s\n", name);
596
	return NULL;
Linus Torvalds's avatar
Linus Torvalds committed
597
}
598
EXPORT_SYMBOL_GPL(find_symbol);
Linus Torvalds's avatar
Linus Torvalds committed
599 600

/* Search for module by name: must hold module_mutex. */
601
static struct module *find_module_all(const char *name, size_t len,
602
				      bool even_unformed)
Linus Torvalds's avatar
Linus Torvalds committed
603 604 605
{
	struct module *mod;

606 607
	module_assert_mutex();

Linus Torvalds's avatar
Linus Torvalds committed
608
	list_for_each_entry(mod, &modules, list) {
609 610
		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
			continue;
611
		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
Linus Torvalds's avatar
Linus Torvalds committed
612 613 614 615
			return mod;
	}
	return NULL;
}
616 617 618

struct module *find_module(const char *name)
{
619
	return find_module_all(name, strlen(name), false);
620
}
621
EXPORT_SYMBOL_GPL(find_module);
Linus Torvalds's avatar
Linus Torvalds committed
622 623

#ifdef CONFIG_SMP
624

625
static inline void __percpu *mod_percpu(struct module *mod)
626
{
627 628
	return mod->percpu;
}
629

Rusty Russell's avatar
Rusty Russell committed
630
static int percpu_modalloc(struct module *mod, struct load_info *info)
631
{
Rusty Russell's avatar
Rusty Russell committed
632 633 634 635 636 637
	Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
	unsigned long align = pcpusec->sh_addralign;

	if (!pcpusec->sh_size)
		return 0;

638
	if (align > PAGE_SIZE) {
639 640
		pr_warn("%s: per-cpu alignment %li > %li\n",
			mod->name, align, PAGE_SIZE);
641 642 643
		align = PAGE_SIZE;
	}

Rusty Russell's avatar
Rusty Russell committed
644
	mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
645
	if (!mod->percpu) {
646 647
		pr_warn("%s: Could not allocate %lu bytes percpu data\n",
			mod->name, (unsigned long)pcpusec->sh_size);
648 649
		return -ENOMEM;
	}
Rusty Russell's avatar
Rusty Russell committed
650
	mod->percpu_size = pcpusec->sh_size;
651
	return 0;
652 653
}

654
static void percpu_modfree(struct module *mod)
655
{
656
	free_percpu(mod->percpu);
657 658
}

659
static unsigned int find_pcpusec(struct load_info *info)
660
{
661
	return find_sec(info, ".data..percpu");
662 663
}

664 665
static void percpu_modcopy(struct module *mod,
			   const void *from, unsigned long size)
666 667 668 669
{
	int cpu;

	for_each_possible_cpu(cpu)
670
		memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
671 672
}

673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689
/**
 * 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) {
690 691
		if (mod->state == MODULE_STATE_UNFORMED)
			continue;
692 693 694 695 696 697 698 699 700 701 702 703 704 705 706
		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;
707 708
}

Linus Torvalds's avatar
Linus Torvalds committed
709
#else /* ... !CONFIG_SMP */
710

711
static inline void __percpu *mod_percpu(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
712 713 714
{
	return NULL;
}
Rusty Russell's avatar
Rusty Russell committed
715
static int percpu_modalloc(struct module *mod, struct load_info *info)
716
{
Rusty Russell's avatar
Rusty Russell committed
717 718 719 720
	/* 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;
721 722
}
static inline void percpu_modfree(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
723 724
{
}
725
static unsigned int find_pcpusec(struct load_info *info)
Linus Torvalds's avatar
Linus Torvalds committed
726 727 728
{
	return 0;
}
729 730
static inline void percpu_modcopy(struct module *mod,
				  const void *from, unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
731 732 733 734
{
	/* pcpusec should be 0, and size of that section should be 0. */
	BUG_ON(size != 0);
}
735 736 737 738
bool is_module_percpu_address(unsigned long addr)
{
	return false;
}
739

Linus Torvalds's avatar
Linus Torvalds committed
740 741
#endif /* CONFIG_SMP */

742 743 744 745 746 747
#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,   \
748
			struct module_kobject *mk, char *buffer)      \
749
{                                                                     \
750
	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
751 752 753 754 755 756 757
}                                                                     \
static int modinfo_##field##_exists(struct module *mod)               \
{                                                                     \
	return mod->field != NULL;                                    \
}                                                                     \
static void free_modinfo_##field(struct module *mod)                  \
{                                                                     \
758 759
	kfree(mod->field);                                            \
	mod->field = NULL;                                            \
760 761
}                                                                     \
static struct module_attribute modinfo_##field = {                    \
762
	.attr = { .name = __stringify(field), .mode = 0444 },         \
763 764 765 766 767 768 769 770 771
	.show = show_modinfo_##field,                                 \
	.setup = setup_modinfo_##field,                               \
	.test = modinfo_##field##_exists,                             \
	.free = free_modinfo_##field,                                 \
};

MODINFO_ATTR(version);
MODINFO_ATTR(srcversion);

772 773
static char last_unloaded_module[MODULE_NAME_LEN+1];

774
#ifdef CONFIG_MODULE_UNLOAD
775 776 777

EXPORT_TRACEPOINT_SYMBOL(module_get);

778 779 780
/* MODULE_REF_BASE is the base reference count by kmodule loader. */
#define MODULE_REF_BASE	1

Linus Torvalds's avatar
Linus Torvalds committed
781
/* Init the unload section of the module. */
782
static int module_unload_init(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
783
{
784 785 786 787 788
	/*
	 * Initialize reference counter to MODULE_REF_BASE.
	 * refcnt == 0 means module is going.
	 */
	atomic_set(&mod->refcnt, MODULE_REF_BASE);
789

790 791
	INIT_LIST_HEAD(&mod->source_list);
	INIT_LIST_HEAD(&mod->target_list);
792

Linus Torvalds's avatar
Linus Torvalds committed
793
	/* Hold reference count during initialization. */
794
	atomic_inc(&mod->refcnt);
795 796

	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
797 798 799 800 801 802 803
}

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

804 805
	list_for_each_entry(use, &b->source_list, source_list) {
		if (use->source == a) {
806
			pr_debug("%s uses %s!\n", a->name, b->name);
Linus Torvalds's avatar
Linus Torvalds committed
807 808 809
			return 1;
		}
	}
810
	pr_debug("%s does not use %s!\n", a->name, b->name);
Linus Torvalds's avatar
Linus Torvalds committed
811 812 813
	return 0;
}

814 815 816 817 818 819 820 821 822 823 824
/*
 * 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;

825
	pr_debug("Allocating new usage for %s.\n", a->name);
826 827
	use = kmalloc(sizeof(*use), GFP_ATOMIC);
	if (!use) {
828
		pr_warn("%s: out of memory loading\n", a->name);
829 830 831 832 833 834 835 836 837 838
		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;
}

839
/* Module a uses b: caller needs module_mutex() */
840
int ref_module(struct module *a, struct module *b)
Linus Torvalds's avatar
Linus Torvalds committed
841
{
842
	int err;
Kay Sievers's avatar
Kay Sievers committed
843

844
	if (b == NULL || already_uses(a, b))
845 846
		return 0;

847 848
	/* If module isn't available, we fail. */
	err = strong_try_module_get(b);
849
	if (err)
850
		return err;
Linus Torvalds's avatar
Linus Torvalds committed
851

852 853
	err = add_module_usage(a, b);
	if (err) {
Linus Torvalds's avatar
Linus Torvalds committed
854
		module_put(b);
855
		return err;
Linus Torvalds's avatar
Linus Torvalds committed
856
	}
857
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
858
}
859
EXPORT_SYMBOL_GPL(ref_module);
Linus Torvalds's avatar
Linus Torvalds committed
860 861 862 863

/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
864
	struct module_use *use, *tmp;
Linus Torvalds's avatar
Linus Torvalds committed
865

866
	mutex_lock(&module_mutex);
867 868
	list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
		struct module *i = use->target;
869
		pr_debug("%s unusing %s\n", mod->name, i->name);
870 871 872 873
		module_put(i);
		list_del(&use->source_list);
		list_del(&use->target_list);
		kfree(use);
Linus Torvalds's avatar
Linus Torvalds committed
874
	}
875
	mutex_unlock(&module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
876 877 878
}

#ifdef CONFIG_MODULE_FORCE_UNLOAD
879
static inline int try_force_unload(unsigned int flags)
Linus Torvalds's avatar
Linus Torvalds committed
880 881 882
{
	int ret = (flags & O_TRUNC);
	if (ret)
883
		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
Linus Torvalds's avatar
Linus Torvalds committed
884 885 886
	return ret;
}
#else
887
static inline int try_force_unload(unsigned int flags)
Linus Torvalds's avatar
Linus Torvalds committed
888 889 890 891 892
{
	return 0;
}
#endif /* CONFIG_MODULE_FORCE_UNLOAD */

893 894
/* 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
895
{
896
	int ret;
Linus Torvalds's avatar
Linus Torvalds committed
897

898 899 900 901 902 903
	/* 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
904

905 906
	return ret;
}
Linus Torvalds's avatar
Linus Torvalds committed
907

908 909
static int try_stop_module(struct module *mod, int flags, int *forced)
{
910
	/* If it's not unused, quit unless we're forcing. */
911 912 913
	if (try_release_module_ref(mod) != 0) {
		*forced = try_force_unload(flags);
		if (!(*forced))
Linus Torvalds's avatar
Linus Torvalds committed
914 915 916 917
			return -EWOULDBLOCK;
	}

	/* Mark it as dying. */
918
	mod->state = MODULE_STATE_GOING;
Linus Torvalds's avatar
Linus Torvalds committed
919

920
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
921 922
}

923 924 925 926 927 928 929 930 931 932
/**
 * 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
933
{
934
	return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
Linus Torvalds's avatar
Linus Torvalds committed
935 936 937 938 939 940
}
EXPORT_SYMBOL(module_refcount);

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

941 942
SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
		unsigned int, flags)
Linus Torvalds's avatar
Linus Torvalds committed
943 944
{
	struct module *mod;
945
	char name[MODULE_NAME_LEN];
Linus Torvalds's avatar
Linus Torvalds committed
946 947
	int ret, forced = 0;

948
	if (!capable(CAP_SYS_MODULE) || modules_disabled)
949 950 951 952 953 954
		return -EPERM;

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

955 956
	if (mutex_lock_interruptible(&module_mutex) != 0)
		return -EINTR;
Linus Torvalds's avatar
Linus Torvalds committed
957 958 959 960 961 962 963

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

964
	if (!list_empty(&mod->source_list)) {
Linus Torvalds's avatar
Linus Torvalds committed
965 966 967 968 969 970 971
		/* 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) {
972
		/* FIXME: if (force), slam module count damn the torpedoes */
973
		pr_debug("%s already dying\n", mod->name);
Linus Torvalds's avatar
Linus Torvalds committed
974 975 976 977 978
		ret = -EBUSY;
		goto out;
	}

	/* If it has an init func, it must have an exit func to unload */
979
	if (mod->init && !mod->exit) {
980
		forced = try_force_unload(flags);
Linus Torvalds's avatar
Linus Torvalds committed
981 982 983 984 985 986 987 988 989 990 991 992
		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;

993
	mutex_unlock(&module_mutex);
Lucas De Marchi's avatar
Lucas De Marchi committed
994
	/* Final destruction now no one is using it. */
995
	if (mod->exit != NULL)
Linus Torvalds's avatar
Linus Torvalds committed
996
		mod->exit();
997 998
	blocking_notifier_call_chain(&module_notify_list,
				     MODULE_STATE_GOING, mod);
999
	async_synchronize_full();
1000

1001
	/* Store the name of the last unloaded module for diagnostic purposes */
1002
	strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
Linus Torvalds's avatar
Linus Torvalds committed
1003

1004 1005 1006
	free_module(mod);
	return 0;
out:
1007
	mutex_unlock(&module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1008 1009 1010
	return ret;
}

1011
static inline void print_unload_info(struct seq_file *m, struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
1012 1013 1014 1015
{
	struct module_use *use;
	int printed_something = 0;

1016
	seq_printf(m, " %i ", module_refcount(mod));
Linus Torvalds's avatar
Linus Torvalds committed
1017

1018 1019 1020 1021
	/*
	 * Always include a trailing , so userspace can differentiate
	 * between this and the old multi-field proc format.
	 */
1022
	list_for_each_entry(use, &mod->source_list, source_list) {
Linus Torvalds's avatar
Linus Torvalds committed
1023
		printed_something = 1;
1024
		seq_printf(m, "%s,", use->source->name);
Linus Torvalds's avatar
Linus Torvalds committed
1025 1026 1027 1028
	}

	if (mod->init != NULL && mod->exit == NULL) {
		printed_something = 1;
1029
		seq_puts(m, "[permanent],");
Linus Torvalds's avatar
Linus Torvalds committed
1030 1031 1032
	}

	if (!printed_something)
1033
		seq_puts(m, "-");
Linus Torvalds's avatar
Linus Torvalds committed
1034 1035 1036 1037 1038 1039
}

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

Rusty Russell's avatar
Rusty Russell committed
1040
	preempt_disable();
1041
	if (!find_symbol(symbol, &owner, NULL, true, false))
Linus Torvalds's avatar
Linus Torvalds committed
1042 1043
		BUG();
	module_put(owner);
Rusty Russell's avatar
Rusty Russell committed
1044
	preempt_enable();
Linus Torvalds's avatar
Linus Torvalds committed
1045 1046 1047
}
EXPORT_SYMBOL(__symbol_put);

1048
/* Note this assumes addr is a function, which it currently always is. */
Linus Torvalds's avatar
Linus Torvalds committed
1049 1050
void symbol_put_addr(void *addr)
{
1051
	struct module *modaddr;
1052
	unsigned long a = (unsigned long)dereference_function_descriptor(addr);
Linus Torvalds's avatar
Linus Torvalds committed
1053

1054
	if (core_kernel_text(a))
1055
		return;
Linus Torvalds's avatar
Linus Torvalds committed
1056

1057 1058
	/* module_text_address is safe here: we're supposed to have reference
	 * to module from symbol_get, so it can't go away. */
1059
	modaddr = __module_text_address(a);
1060
	BUG_ON(!modaddr);
1061
	module_put(modaddr);
Linus Torvalds's avatar
Linus Torvalds committed
1062 1063 1064 1065
}
EXPORT_SYMBOL_GPL(symbol_put_addr);

static ssize_t show_refcnt(struct module_attribute *mattr,
1066
			   struct module_kobject *mk, char *buffer)
Linus Torvalds's avatar
Linus Torvalds committed
1067
{
1068
	return sprintf(buffer, "%i\n", module_refcount(mk->mod));
Linus Torvalds's avatar
Linus Torvalds committed
1069 1070
}

1071 1072
static struct module_attribute modinfo_refcnt =
	__ATTR(refcnt, 0444, show_refcnt, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
1073

1074 1075 1076 1077
void __module_get(struct module *module)
{
	if (module) {
		preempt_disable();
1078
		atomic_inc(&module->refcnt);
1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090
		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();
1091 1092 1093
		/* Note: here, we can fail to get a reference */
		if (likely(module_is_live(module) &&
			   atomic_inc_not_zero(&module->refcnt) != 0))
1094
			trace_module_get(module, _RET_IP_);
1095
		else
1096 1097 1098 1099 1100 1101 1102 1103
			ret = false;

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

Al Viro's avatar
Al Viro committed
1104 1105
void module_put(struct module *module)
{
1106 1107
	int ret;

Al Viro's avatar
Al Viro committed
1108
	if (module) {
1109
		preempt_disable();
1110 1111
		ret = atomic_dec_if_positive(&module->refcnt);
		WARN_ON(ret < 0);	/* Failed to put refcount */
1112
		trace_module_put(module, _RET_IP_);
1113
		preempt_enable();
Al Viro's avatar
Al Viro committed
1114 1115 1116 1117
	}
}
EXPORT_SYMBOL(module_put);

Linus Torvalds's avatar
Linus Torvalds committed
1118
#else /* !CONFIG_MODULE_UNLOAD */
1119
static inline void print_unload_info(struct seq_file *m, struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
1120 1121
{
	/* We don't know the usage count, or what modules are using. */
1122
	seq_puts(m, " - -");
Linus Torvalds's avatar
Linus Torvalds committed
1123 1124 1125 1126 1127 1128
}

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

1129
int ref_module(struct module *a, struct module *b)
Linus Torvalds's avatar
Linus Torvalds committed
1130
{
1131
	return strong_try_module_get(b);
Linus Torvalds's avatar
Linus Torvalds committed
1132
}
1133
EXPORT_SYMBOL_GPL(ref_module);
Linus Torvalds's avatar
Linus Torvalds committed
1134

1135
static inline int module_unload_init(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
1136
{
1137
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
1138 1139 1140
}
#endif /* CONFIG_MODULE_UNLOAD */

1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152
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';
1153
	if (mod->taints & (1 << TAINT_UNSIGNED_MODULE))
1154
		buf[l++] = 'E';
1155 1156
	/*
	 * TAINT_FORCED_RMMOD: could be added.
1157
	 * TAINT_CPU_OUT_OF_SPEC, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
1158 1159 1160 1161 1162
	 * apply to modules.
	 */
	return l;
}

1163
static ssize_t show_initstate(struct module_attribute *mattr,
1164
			      struct module_kobject *mk, char *buffer)
1165 1166 1167
{
	const char *state = "unknown";

1168
	switch (mk->mod->state) {
1169 1170 1171 1172 1173 1174 1175 1176 1177
	case MODULE_STATE_LIVE:
		state = "live";
		break;
	case MODULE_STATE_COMING:
		state = "coming";
		break;
	case MODULE_STATE_GOING:
		state = "going";
		break;
1178 1179
	default:
		BUG();
1180 1181 1182 1183
	}
	return sprintf(buffer, "%s\n", state);
}

1184 1185
static struct module_attribute modinfo_initstate =
	__ATTR(initstate, 0444, show_initstate, NULL);