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kernel_optimize_test/kernel/module.c
Rusty Russell 9bea7f2395 module: fix bne2 "gave up waiting for init of module libcrc32c" 
Problem: it's hard to avoid an init routine stumbling over a
request_module these days.  And it's not clear it's always a bad idea:
for example, a module like kvm with dynamic dependencies on kvm-intel
or kvm-amd would be neater if it could simply request_module the right
one.

In this particular case, it's libcrc32c:

	libcrc32c_mod_init
	 crypto_alloc_shash
	  crypto_alloc_tfm
	   crypto_find_alg
	    crypto_alg_mod_lookup
	     crypto_larval_lookup
	      request_module

If another module is waiting inside resolve_symbol() for libcrc32c to
finish initializing (ie. bne2 depends on libcrc32c) then it does so
holding the module lock, and our request_module() can't make progress
until that is released.

Waiting inside resolve_symbol() without the lock isn't all that hard:
we just need to pass the -EBUSY up the call chain so we can sleep
where we don't hold the lock.  Error reporting is a bit trickier: we
need to copy the name of the unfinished module before releasing the
lock.

Other notes:
1) This also fixes a theoretical issue where a weak dependency would allow
   symbol version mismatches to be ignored.
2) We rename use_module to ref_module to make life easier for the only
   external user (the out-of-tree ksplice patches).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tim Abbot <tabbott@ksplice.com>
Tested-by: Brandon Philips <bphilips@suse.de>
2010-06-05 11:17:37 +09:30

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/*
Copyright (C) 2002 Richard Henderson
Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
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
*/
#include <linux/module.h>
#include <linux/moduleloader.h>
#include <linux/ftrace_event.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <linux/rcupdate.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/vermagic.h>
#include <linux/notifier.h>
#include <linux/sched.h>
#include <linux/stop_machine.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/rculist.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <linux/license.h>
#include <asm/sections.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
#include <linux/async.h>
#include <linux/percpu.h>
#include <linux/kmemleak.h>
#define CREATE_TRACE_POINTS
#include <trace/events/module.h>
#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt , a...)
#endif
#ifndef ARCH_SHF_SMALL
#define ARCH_SHF_SMALL 0
#endif
/* If this is set, the section belongs in the init part of the module */
#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
/*
* Mutex protects:
* 1) List of modules (also safely readable with preempt_disable),
* 2) module_use links,
* 3) module_addr_min/module_addr_max.
* (delete uses stop_machine/add uses RCU list operations). */
DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);
#ifdef CONFIG_KGDB_KDB
struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
#endif /* CONFIG_KGDB_KDB */
/* Block module loading/unloading? */
int modules_disabled = 0;
/* Waiting for a module to finish initializing? */
static DECLARE_WAIT_QUEUE_HEAD(module_wq);
static BLOCKING_NOTIFIER_HEAD(module_notify_list);
/* Bounds of module allocation, for speeding __module_address.
* Protected by module_mutex. */
static unsigned long module_addr_min = -1UL, module_addr_max = 0;
int register_module_notifier(struct notifier_block * nb)
{
return blocking_notifier_chain_register(&module_notify_list, nb);
}
EXPORT_SYMBOL(register_module_notifier);
int unregister_module_notifier(struct notifier_block * nb)
{
return blocking_notifier_chain_unregister(&module_notify_list, nb);
}
EXPORT_SYMBOL(unregister_module_notifier);
/* We require a truly strong try_module_get(): 0 means failure due to
ongoing or failed initialization etc. */
static inline int strong_try_module_get(struct module *mod)
{
if (mod && mod->state == MODULE_STATE_COMING)
return -EBUSY;
if (try_module_get(mod))
return 0;
else
return -ENOENT;
}
static inline void add_taint_module(struct module *mod, unsigned flag)
{
add_taint(flag);
mod->taints |= (1U << flag);
}
/*
* 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.
*/
void __module_put_and_exit(struct module *mod, long code)
{
module_put(mod);
do_exit(code);
}
EXPORT_SYMBOL(__module_put_and_exit);
/* Find a module section: 0 means not found. */
static unsigned int find_sec(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
const char *secstrings,
const char *name)
{
unsigned int i;
for (i = 1; i < hdr->e_shnum; i++)
/* Alloc bit cleared means "ignore it." */
if ((sechdrs[i].sh_flags & SHF_ALLOC)
&& strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
return i;
return 0;
}
/* Find a module section, or NULL. */
static void *section_addr(Elf_Ehdr *hdr, Elf_Shdr *shdrs,
const char *secstrings, const char *name)
{
/* Section 0 has sh_addr 0. */
return (void *)shdrs[find_sec(hdr, shdrs, secstrings, name)].sh_addr;
}
/* Find a module section, or NULL. Fill in number of "objects" in section. */
static void *section_objs(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
const char *secstrings,
const char *name,
size_t object_size,
unsigned int *num)
{
unsigned int sec = find_sec(hdr, sechdrs, secstrings, name);
/* Section 0 has sh_addr 0 and sh_size 0. */
*num = sechdrs[sec].sh_size / object_size;
return (void *)sechdrs[sec].sh_addr;
}
/* 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[];
extern const struct kernel_symbol __start___ksymtab_gpl_future[];
extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
extern const unsigned long __start___kcrctab[];
extern const unsigned long __start___kcrctab_gpl[];
extern const unsigned long __start___kcrctab_gpl_future[];
#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[];
extern const unsigned long __start___kcrctab_unused[];
extern const unsigned long __start___kcrctab_unused_gpl[];
#endif
#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
#else
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
#endif
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,
unsigned int symnum, void *data),
void *data)
{
unsigned int i, j;
for (j = 0; j < arrsize; j++) {
for (i = 0; i < arr[j].stop - arr[j].start; i++)
if (fn(&arr[j], owner, i, data))
return true;
}
return false;
}
/* Returns true as soon as fn returns true, otherwise false. */
bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner,
unsigned int symnum, void *data), void *data)
{
struct module *mod;
const struct symsearch arr[] = {
{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
NOT_GPL_ONLY, false },
{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
__start___kcrctab_gpl,
GPL_ONLY, false },
{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
__start___kcrctab_gpl_future,
WILL_BE_GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
{ __start___ksymtab_unused, __stop___ksymtab_unused,
__start___kcrctab_unused,
NOT_GPL_ONLY, true },
{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
__start___kcrctab_unused_gpl,
GPL_ONLY, true },
#endif
};
if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
return true;
list_for_each_entry_rcu(mod, &modules, list) {
struct symsearch arr[] = {
{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
NOT_GPL_ONLY, false },
{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
mod->gpl_crcs,
GPL_ONLY, false },
{ mod->gpl_future_syms,
mod->gpl_future_syms + mod->num_gpl_future_syms,
mod->gpl_future_crcs,
WILL_BE_GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
{ mod->unused_syms,
mod->unused_syms + mod->num_unused_syms,
mod->unused_crcs,
NOT_GPL_ONLY, true },
{ mod->unused_gpl_syms,
mod->unused_gpl_syms + mod->num_unused_gpl_syms,
mod->unused_gpl_crcs,
GPL_ONLY, true },
#endif
};
if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
return true;
}
return false;
}
EXPORT_SYMBOL_GPL(each_symbol);
struct find_symbol_arg {
/* Input */
const char *name;
bool gplok;
bool warn;
/* Output */
struct module *owner;
const unsigned long *crc;
const struct kernel_symbol *sym;
};
static bool find_symbol_in_section(const struct symsearch *syms,
struct module *owner,
unsigned int symnum, void *data)
{
struct find_symbol_arg *fsa = data;
if (strcmp(syms->start[symnum].name, fsa->name) != 0)
return false;
if (!fsa->gplok) {
if (syms->licence == GPL_ONLY)
return false;
if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
printk(KERN_WARNING "Symbol %s is being used "
"by a non-GPL module, which will not "
"be allowed in the future\n", fsa->name);
printk(KERN_WARNING "Please see the file "
"Documentation/feature-removal-schedule.txt "
"in the kernel source tree for more details.\n");
}
}
#ifdef CONFIG_UNUSED_SYMBOLS
if (syms->unused && fsa->warn) {
printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
"however this module is using it.\n", fsa->name);
printk(KERN_WARNING
"This symbol will go away in the future.\n");
printk(KERN_WARNING
"Please evalute if this is the right api to use and if "
"it really is, submit a report the linux kernel "
"mailinglist together with submitting your code for "
"inclusion.\n");
}
#endif
fsa->owner = owner;
fsa->crc = symversion(syms->crcs, symnum);
fsa->sym = &syms->start[symnum];
return true;
}
/* Find a symbol and return it, along with, (optional) crc and
* (optional) module which owns it. Needs preempt disabled or module_mutex. */
const struct kernel_symbol *find_symbol(const char *name,
struct module **owner,
const unsigned long **crc,
bool gplok,
bool warn)
{
struct find_symbol_arg fsa;
fsa.name = name;
fsa.gplok = gplok;
fsa.warn = warn;
if (each_symbol(find_symbol_in_section, &fsa)) {
if (owner)
*owner = fsa.owner;
if (crc)
*crc = fsa.crc;
return fsa.sym;
}
DEBUGP("Failed to find symbol %s\n", name);
return NULL;
}
EXPORT_SYMBOL_GPL(find_symbol);
/* Search for module by name: must hold module_mutex. */
struct module *find_module(const char *name)
{
struct module *mod;
list_for_each_entry(mod, &modules, list) {
if (strcmp(mod->name, name) == 0)
return mod;
}
return NULL;
}
EXPORT_SYMBOL_GPL(find_module);
#ifdef CONFIG_SMP
static inline void __percpu *mod_percpu(struct module *mod)
{
return mod->percpu;
}
static int percpu_modalloc(struct module *mod,
unsigned long size, unsigned long align)
{
if (align > PAGE_SIZE) {
printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
mod->name, align, PAGE_SIZE);
align = PAGE_SIZE;
}
mod->percpu = __alloc_reserved_percpu(size, align);
if (!mod->percpu) {
printk(KERN_WARNING
"Could not allocate %lu bytes percpu data\n", size);
return -ENOMEM;
}
mod->percpu_size = size;
return 0;
}
static void percpu_modfree(struct module *mod)
{
free_percpu(mod->percpu);
}
static unsigned int find_pcpusec(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
const char *secstrings)
{
return find_sec(hdr, sechdrs, secstrings, ".data..percpu");
}
static void percpu_modcopy(struct module *mod,
const void *from, unsigned long size)
{
int cpu;
for_each_possible_cpu(cpu)
memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
}
/**
* 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) {
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;
}
#else /* ... !CONFIG_SMP */
static inline void __percpu *mod_percpu(struct module *mod)
{
return NULL;
}
static inline int percpu_modalloc(struct module *mod,
unsigned long size, unsigned long align)
{
return -ENOMEM;
}
static inline void percpu_modfree(struct module *mod)
{
}
static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
const char *secstrings)
{
return 0;
}
static inline void percpu_modcopy(struct module *mod,
const void *from, unsigned long size)
{
/* pcpusec should be 0, and size of that section should be 0. */
BUG_ON(size != 0);
}
bool is_module_percpu_address(unsigned long addr)
{
return false;
}
#endif /* CONFIG_SMP */
#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, \
struct module *mod, char *buffer) \
{ \
return sprintf(buffer, "%s\n", mod->field); \
} \
static int modinfo_##field##_exists(struct module *mod) \
{ \
return mod->field != NULL; \
} \
static void free_modinfo_##field(struct module *mod) \
{ \
kfree(mod->field); \
mod->field = NULL; \
} \
static struct module_attribute modinfo_##field = { \
.attr = { .name = __stringify(field), .mode = 0444 }, \
.show = show_modinfo_##field, \
.setup = setup_modinfo_##field, \
.test = modinfo_##field##_exists, \
.free = free_modinfo_##field, \
};
MODINFO_ATTR(version);
MODINFO_ATTR(srcversion);
static char last_unloaded_module[MODULE_NAME_LEN+1];
#ifdef CONFIG_MODULE_UNLOAD
EXPORT_TRACEPOINT_SYMBOL(module_get);
/* Init the unload section of the module. */
static void module_unload_init(struct module *mod)
{
int cpu;
INIT_LIST_HEAD(&mod->source_list);
INIT_LIST_HEAD(&mod->target_list);
for_each_possible_cpu(cpu) {
per_cpu_ptr(mod->refptr, cpu)->incs = 0;
per_cpu_ptr(mod->refptr, cpu)->decs = 0;
}
/* Hold reference count during initialization. */
__this_cpu_write(mod->refptr->incs, 1);
/* Backwards compatibility macros put refcount during init. */
mod->waiter = current;
}
/* Does a already use b? */
static int already_uses(struct module *a, struct module *b)
{
struct module_use *use;
list_for_each_entry(use, &b->source_list, source_list) {
if (use->source == a) {
DEBUGP("%s uses %s!\n", a->name, b->name);
return 1;
}
}
DEBUGP("%s does not use %s!\n", a->name, b->name);
return 0;
}
/*
* 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;
DEBUGP("Allocating new usage for %s.\n", a->name);
use = kmalloc(sizeof(*use), GFP_ATOMIC);
if (!use) {
printk(KERN_WARNING "%s: out of memory loading\n", a->name);
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;
}
/* Module a uses b: caller needs module_mutex() */
int ref_module(struct module *a, struct module *b)
{
int err;
if (b == NULL || already_uses(a, b))
return 0;
/* If module isn't available, we fail. */
err = strong_try_module_get(b);
if (err)
return err;
err = add_module_usage(a, b);
if (err) {
module_put(b);
return err;
}
return 0;
}
EXPORT_SYMBOL_GPL(ref_module);
/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
struct module_use *use, *tmp;
mutex_lock(&module_mutex);
list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
struct module *i = use->target;
DEBUGP("%s unusing %s\n", mod->name, i->name);
module_put(i);
list_del(&use->source_list);
list_del(&use->target_list);
kfree(use);
}
mutex_unlock(&module_mutex);
}
#ifdef CONFIG_MODULE_FORCE_UNLOAD
static inline int try_force_unload(unsigned int flags)
{
int ret = (flags & O_TRUNC);
if (ret)
add_taint(TAINT_FORCED_RMMOD);
return ret;
}
#else
static inline int try_force_unload(unsigned int flags)
{
return 0;
}
#endif /* CONFIG_MODULE_FORCE_UNLOAD */
struct stopref
{
struct module *mod;
int flags;
int *forced;
};
/* Whole machine is stopped with interrupts off when this runs. */
static int __try_stop_module(void *_sref)
{
struct stopref *sref = _sref;
/* If it's not unused, quit unless we're forcing. */
if (module_refcount(sref->mod) != 0) {
if (!(*sref->forced = try_force_unload(sref->flags)))
return -EWOULDBLOCK;
}
/* Mark it as dying. */
sref->mod->state = MODULE_STATE_GOING;
return 0;
}
static int try_stop_module(struct module *mod, int flags, int *forced)
{
if (flags & O_NONBLOCK) {
struct stopref sref = { mod, flags, forced };
return stop_machine(__try_stop_module, &sref, NULL);
} else {
/* We don't need to stop the machine for this. */
mod->state = MODULE_STATE_GOING;
synchronize_sched();
return 0;
}
}
unsigned int module_refcount(struct module *mod)
{
unsigned int incs = 0, decs = 0;
int cpu;
for_each_possible_cpu(cpu)
decs += per_cpu_ptr(mod->refptr, cpu)->decs;
/*
* ensure the incs are added up after the decs.
* module_put ensures incs are visible before decs with smp_wmb.
*
* This 2-count scheme avoids the situation where the refcount
* for CPU0 is read, then CPU0 increments the module refcount,
* then CPU1 drops that refcount, then the refcount for CPU1 is
* read. We would record a decrement but not its corresponding
* increment so we would see a low count (disaster).
*
* Rare situation? But module_refcount can be preempted, and we
* might be tallying up 4096+ CPUs. So it is not impossible.
*/
smp_rmb();
for_each_possible_cpu(cpu)
incs += per_cpu_ptr(mod->refptr, cpu)->incs;
return incs - decs;
}
EXPORT_SYMBOL(module_refcount);
/* This exists whether we can unload or not */
static void free_module(struct module *mod);
static void wait_for_zero_refcount(struct module *mod)
{
/* Since we might sleep for some time, release the mutex first */
mutex_unlock(&module_mutex);
for (;;) {
DEBUGP("Looking at refcount...\n");
set_current_state(TASK_UNINTERRUPTIBLE);
if (module_refcount(mod) == 0)
break;
schedule();
}
current->state = TASK_RUNNING;
mutex_lock(&module_mutex);
}
SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
unsigned int, flags)
{
struct module *mod;
char name[MODULE_NAME_LEN];
int ret, forced = 0;
if (!capable(CAP_SYS_MODULE) || modules_disabled)
return -EPERM;
if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
return -EFAULT;
name[MODULE_NAME_LEN-1] = '\0';
if (mutex_lock_interruptible(&module_mutex) != 0)
return -EINTR;
mod = find_module(name);
if (!mod) {
ret = -ENOENT;
goto out;
}
if (!list_empty(&mod->source_list)) {
/* 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) {
/* FIXME: if (force), slam module count and wake up
waiter --RR */
DEBUGP("%s already dying\n", mod->name);
ret = -EBUSY;
goto out;
}
/* If it has an init func, it must have an exit func to unload */
if (mod->init && !mod->exit) {
forced = try_force_unload(flags);
if (!forced) {
/* This module can't be removed */
ret = -EBUSY;
goto out;
}
}
/* Set this up before setting mod->state */
mod->waiter = current;
/* Stop the machine so refcounts can't move and disable module. */
ret = try_stop_module(mod, flags, &forced);
if (ret != 0)
goto out;
/* Never wait if forced. */
if (!forced && module_refcount(mod) != 0)
wait_for_zero_refcount(mod);
mutex_unlock(&module_mutex);
/* Final destruction now noone is using it. */
if (mod->exit != NULL)
mod->exit();
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
async_synchronize_full();
/* Store the name of the last unloaded module for diagnostic purposes */
strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
ddebug_remove_module(mod->name);
free_module(mod);
return 0;
out:
mutex_unlock(&module_mutex);
return ret;
}
static inline void print_unload_info(struct seq_file *m, struct module *mod)
{
struct module_use *use;
int printed_something = 0;
seq_printf(m, " %u ", module_refcount(mod));
/* Always include a trailing , so userspace can differentiate
between this and the old multi-field proc format. */
list_for_each_entry(use, &mod->source_list, source_list) {
printed_something = 1;
seq_printf(m, "%s,", use->source->name);
}
if (mod->init != NULL && mod->exit == NULL) {
printed_something = 1;
seq_printf(m, "[permanent],");
}
if (!printed_something)
seq_printf(m, "-");
}
void __symbol_put(const char *symbol)
{
struct module *owner;
preempt_disable();
if (!find_symbol(symbol, &owner, NULL, true, false))
BUG();
module_put(owner);
preempt_enable();
}
EXPORT_SYMBOL(__symbol_put);
/* Note this assumes addr is a function, which it currently always is. */
void symbol_put_addr(void *addr)
{
struct module *modaddr;
unsigned long a = (unsigned long)dereference_function_descriptor(addr);
if (core_kernel_text(a))
return;
/* module_text_address is safe here: we're supposed to have reference
* to module from symbol_get, so it can't go away. */
modaddr = __module_text_address(a);
BUG_ON(!modaddr);
module_put(modaddr);
}
EXPORT_SYMBOL_GPL(symbol_put_addr);
static ssize_t show_refcnt(struct module_attribute *mattr,
struct module *mod, char *buffer)
{
return sprintf(buffer, "%u\n", module_refcount(mod));
}
static struct module_attribute refcnt = {
.attr = { .name = "refcnt", .mode = 0444 },
.show = show_refcnt,
};
void module_put(struct module *module)
{
if (module) {
preempt_disable();
smp_wmb(); /* see comment in module_refcount */
__this_cpu_inc(module->refptr->decs);
trace_module_put(module, _RET_IP_);
/* Maybe they're waiting for us to drop reference? */
if (unlikely(!module_is_live(module)))
wake_up_process(module->waiter);
preempt_enable();
}
}
EXPORT_SYMBOL(module_put);
#else /* !CONFIG_MODULE_UNLOAD */
static inline void print_unload_info(struct seq_file *m, struct module *mod)
{
/* We don't know the usage count, or what modules are using. */
seq_printf(m, " - -");
}
static inline void module_unload_free(struct module *mod)
{
}
int ref_module(struct module *a, struct module *b)
{
return strong_try_module_get(b);
}
EXPORT_SYMBOL_GPL(ref_module);
static inline void module_unload_init(struct module *mod)
{
}
#endif /* CONFIG_MODULE_UNLOAD */
static ssize_t show_initstate(struct module_attribute *mattr,
struct module *mod, char *buffer)
{
const char *state = "unknown";
switch (mod->state) {
case MODULE_STATE_LIVE:
state = "live";
break;
case MODULE_STATE_COMING:
state = "coming";
break;
case MODULE_STATE_GOING:
state = "going";
break;
}
return sprintf(buffer, "%s\n", state);
}
static struct module_attribute initstate = {
.attr = { .name = "initstate", .mode = 0444 },
.show = show_initstate,
};
static struct module_attribute *modinfo_attrs[] = {
&modinfo_version,
&modinfo_srcversion,
&initstate,
#ifdef CONFIG_MODULE_UNLOAD
&refcnt,
#endif
NULL,
};
static const char vermagic[] = VERMAGIC_STRING;
static int try_to_force_load(struct module *mod, const char *reason)
{
#ifdef CONFIG_MODULE_FORCE_LOAD
if (!test_taint(TAINT_FORCED_MODULE))
printk(KERN_WARNING "%s: %s: kernel tainted.\n",
mod->name, reason);
add_taint_module(mod, TAINT_FORCED_MODULE);
return 0;
#else
return -ENOEXEC;
#endif
}
#ifdef CONFIG_MODVERSIONS
/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
static unsigned long maybe_relocated(unsigned long crc,
const struct module *crc_owner)
{
#ifdef ARCH_RELOCATES_KCRCTAB
if (crc_owner == NULL)
return crc - (unsigned long)reloc_start;
#endif
return crc;
}
static int check_version(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *symname,
struct module *mod,
const unsigned long *crc,
const struct module *crc_owner)
{
unsigned int i, num_versions;
struct modversion_info *versions;
/* Exporting module didn't supply crcs? OK, we're already tainted. */
if (!crc)
return 1;
/* No versions at all? modprobe --force does this. */
if (versindex == 0)
return try_to_force_load(mod, symname) == 0;
versions = (void *) sechdrs[versindex].sh_addr;
num_versions = sechdrs[versindex].sh_size
/ sizeof(struct modversion_info);
for (i = 0; i < num_versions; i++) {
if (strcmp(versions[i].name, symname) != 0)
continue;
if (versions[i].crc == maybe_relocated(*crc, crc_owner))
return 1;
DEBUGP("Found checksum %lX vs module %lX\n",
maybe_relocated(*crc, crc_owner), versions[i].crc);
goto bad_version;
}
printk(KERN_WARNING "%s: no symbol version for %s\n",
mod->name, symname);
return 0;
bad_version:
printk("%s: disagrees about version of symbol %s\n",
mod->name, symname);
return 0;
}
static inline int check_modstruct_version(Elf_Shdr *sechdrs,
unsigned int versindex,
struct module *mod)
{
const unsigned long *crc;
/* Since this should be found in kernel (which can't be removed),
* no locking is necessary. */
if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
&crc, true, false))
BUG();
return check_version(sechdrs, versindex, "module_layout", mod, crc,
NULL);
}
/* First part is kernel version, which we ignore if module has crcs. */
static inline int same_magic(const char *amagic, const char *bmagic,
bool has_crcs)
{
if (has_crcs) {
amagic += strcspn(amagic, " ");
bmagic += strcspn(bmagic, " ");
}
return strcmp(amagic, bmagic) == 0;
}
#else
static inline int check_version(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *symname,
struct module *mod,
const unsigned long *crc,
const struct module *crc_owner)
{
return 1;
}
static inline int check_modstruct_version(Elf_Shdr *sechdrs,
unsigned int versindex,
struct module *mod)
{
return 1;
}
static inline int same_magic(const char *amagic, const char *bmagic,
bool has_crcs)
{
return strcmp(amagic, bmagic) == 0;
}
#endif /* CONFIG_MODVERSIONS */
/* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *name,
struct module *mod,
char ownername[])
{
struct module *owner;
const struct kernel_symbol *sym;
const unsigned long *crc;
int err;
mutex_lock(&module_mutex);
sym = find_symbol(name, &owner, &crc,
!(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
if (!sym)
goto unlock;
if (!check_version(sechdrs, versindex, name, mod, crc, owner)) {
sym = ERR_PTR(-EINVAL);
goto getname;
}
err = ref_module(mod, owner);
if (err) {
sym = ERR_PTR(err);
goto getname;
}
getname:
/* We must make copy under the lock if we failed to get ref. */
strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
unlock:
mutex_unlock(&module_mutex);
return sym;
}
static const struct kernel_symbol *resolve_symbol_wait(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *name,
struct module *mod)
{
const struct kernel_symbol *ksym;
char ownername[MODULE_NAME_LEN];
if (wait_event_interruptible_timeout(module_wq,
!IS_ERR(ksym = resolve_symbol(sechdrs, versindex, name,
mod, ownername)) ||
PTR_ERR(ksym) != -EBUSY,
30 * HZ) <= 0) {
printk(KERN_WARNING "%s: gave up waiting for init of module %s.\n",
mod->name, ownername);
}
return ksym;
}
/*
* /sys/module/foo/sections stuff
* J. Corbet <corbet@lwn.net>
*/
#if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS)
static inline bool sect_empty(const Elf_Shdr *sect)
{
return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
}
struct module_sect_attr
{
struct module_attribute mattr;
char *name;
unsigned long address;
};
struct module_sect_attrs
{
struct attribute_group grp;
unsigned int nsections;
struct module_sect_attr attrs[0];
};
static ssize_t module_sect_show(struct module_attribute *mattr,
struct module *mod, char *buf)
{
struct module_sect_attr *sattr =
container_of(mattr, struct module_sect_attr, mattr);
return sprintf(buf, "0x%lx\n", sattr->address);
}
static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
{
unsigned int section;
for (section = 0; section < sect_attrs->nsections; section++)
kfree(sect_attrs->attrs[section].name);
kfree(sect_attrs);
}
static void add_sect_attrs(struct module *mod, unsigned int nsect,
char *secstrings, Elf_Shdr *sechdrs)
{
unsigned int nloaded = 0, i, size[2];
struct module_sect_attrs *sect_attrs;
struct module_sect_attr *sattr;
struct attribute **gattr;
/* Count loaded sections and allocate structures */
for (i = 0; i < nsect; i++)
if (!sect_empty(&sechdrs[i]))
nloaded++;
size[0] = ALIGN(sizeof(*sect_attrs)
+ nloaded * sizeof(sect_attrs->attrs[0]),
sizeof(sect_attrs->grp.attrs[0]));
size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]);
sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
if (sect_attrs == NULL)
return;
/* Setup section attributes. */
sect_attrs->grp.name = "sections";
sect_attrs->grp.attrs = (void *)sect_attrs + size[0];
sect_attrs->nsections = 0;
sattr = &sect_attrs->attrs[0];
gattr = &sect_attrs->grp.attrs[0];
for (i = 0; i < nsect; i++) {
if (sect_empty(&sechdrs[i]))
continue;
sattr->address = sechdrs[i].sh_addr;
sattr->name = kstrdup(secstrings + sechdrs[i].sh_name,
GFP_KERNEL);
if (sattr->name == NULL)
goto out;
sect_attrs->nsections++;
sysfs_attr_init(&sattr->mattr.attr);
sattr->mattr.show = module_sect_show;
sattr->mattr.store = NULL;
sattr->mattr.attr.name = sattr->name;
sattr->mattr.attr.mode = S_IRUGO;
*(gattr++) = &(sattr++)->mattr.attr;
}
*gattr = NULL;
if (sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp))
goto out;
mod->sect_attrs = sect_attrs;
return;
out:
free_sect_attrs(sect_attrs);
}
static void remove_sect_attrs(struct module *mod)
{
if (mod->sect_attrs) {
sysfs_remove_group(&mod->mkobj.kobj,
&mod->sect_attrs->grp);
/* We are positive that no one is using any sect attrs
* at this point. Deallocate immediately. */
free_sect_attrs(mod->sect_attrs);
mod->sect_attrs = NULL;
}
}
/*
* /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
*/
struct module_notes_attrs {
struct kobject *dir;
unsigned int notes;
struct bin_attribute attrs[0];
};
static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t count)
{
/*
* The caller checked the pos and count against our size.
*/
memcpy(buf, bin_attr->private + pos, count);
return count;
}
static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
unsigned int i)
{
if (notes_attrs->dir) {
while (i-- > 0)
sysfs_remove_bin_file(notes_attrs->dir,
&notes_attrs->attrs[i]);
kobject_put(notes_attrs->dir);
}
kfree(notes_attrs);
}
static void add_notes_attrs(struct module *mod, unsigned int nsect,
char *secstrings, Elf_Shdr *sechdrs)
{
unsigned int notes, loaded, i;
struct module_notes_attrs *notes_attrs;
struct bin_attribute *nattr;
/* failed to create section attributes, so can't create notes */
if (!mod->sect_attrs)
return;
/* Count notes sections and allocate structures. */
notes = 0;
for (i = 0; i < nsect; i++)
if (!sect_empty(&sechdrs[i]) &&
(sechdrs[i].sh_type == SHT_NOTE))
++notes;
if (notes == 0)
return;
notes_attrs = kzalloc(sizeof(*notes_attrs)
+ notes * sizeof(notes_attrs->attrs[0]),
GFP_KERNEL);
if (notes_attrs == NULL)
return;
notes_attrs->notes = notes;
nattr = &notes_attrs->attrs[0];
for (loaded = i = 0; i < nsect; ++i) {
if (sect_empty(&sechdrs[i]))
continue;
if (sechdrs[i].sh_type == SHT_NOTE) {
sysfs_bin_attr_init(nattr);
nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
nattr->attr.mode = S_IRUGO;
nattr->size = sechdrs[i].sh_size;
nattr->private = (void *) sechdrs[i].sh_addr;
nattr->read = module_notes_read;
++nattr;
}
++loaded;
}
notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
if (!notes_attrs->dir)
goto out;
for (i = 0; i < notes; ++i)
if (sysfs_create_bin_file(notes_attrs->dir,
&notes_attrs->attrs[i]))
goto out;
mod->notes_attrs = notes_attrs;
return;
out:
free_notes_attrs(notes_attrs, i);
}
static void remove_notes_attrs(struct module *mod)
{
if (mod->notes_attrs)
free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
}
#else
static inline void add_sect_attrs(struct module *mod, unsigned int nsect,
char *sectstrings, Elf_Shdr *sechdrs)
{
}
static inline void remove_sect_attrs(struct module *mod)
{
}
static inline void add_notes_attrs(struct module *mod, unsigned int nsect,
char *sectstrings, Elf_Shdr *sechdrs)
{
}
static inline void remove_notes_attrs(struct module *mod)
{
}
#endif
#ifdef CONFIG_SYSFS
static void add_usage_links(struct module *mod)
{
#ifdef CONFIG_MODULE_UNLOAD
struct module_use *use;
int nowarn;
mutex_lock(&module_mutex);
list_for_each_entry(use, &mod->target_list, target_list) {
nowarn = sysfs_create_link(use->target->holders_dir,
&mod->mkobj.kobj, mod->name);
}
mutex_unlock(&module_mutex);
#endif
}
static void del_usage_links(struct module *mod)
{
#ifdef CONFIG_MODULE_UNLOAD
struct module_use *use;
mutex_lock(&module_mutex);
list_for_each_entry(use, &mod->target_list, target_list)
sysfs_remove_link(use->target->holders_dir, mod->name);
mutex_unlock(&module_mutex);
#endif
}
static int module_add_modinfo_attrs(struct module *mod)
{
struct module_attribute *attr;
struct module_attribute *temp_attr;
int error = 0;
int i;
mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
(ARRAY_SIZE(modinfo_attrs) + 1)),
GFP_KERNEL);
if (!mod->modinfo_attrs)
return -ENOMEM;
temp_attr = mod->modinfo_attrs;
for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
if (!attr->test ||
(attr->test && attr->test(mod))) {
memcpy(temp_attr, attr, sizeof(*temp_attr));
sysfs_attr_init(&temp_attr->attr);
error = sysfs_create_file(&mod->mkobj.kobj,&temp_attr->attr);
++temp_attr;
}
}
return error;
}
static void module_remove_modinfo_attrs(struct module *mod)
{
struct module_attribute *attr;
int i;
for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
/* pick a field to test for end of list */
if (!attr->attr.name)
break;
sysfs_remove_file(&mod->mkobj.kobj,&attr->attr);
if (attr->free)
attr->free(mod);
}
kfree(mod->modinfo_attrs);
}
static int mod_sysfs_init(struct module *mod)
{
int err;
struct kobject *kobj;
if (!module_sysfs_initialized) {
printk(KERN_ERR "%s: module sysfs not initialized\n",
mod->name);
err = -EINVAL;
goto out;
}
kobj = kset_find_obj(module_kset, mod->name);
if (kobj) {
printk(KERN_ERR "%s: module is already loaded\n", mod->name);
kobject_put(kobj);
err = -EINVAL;
goto out;
}
mod->mkobj.mod = mod;
memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
mod->mkobj.kobj.kset = module_kset;
err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
"%s", mod->name);
if (err)
kobject_put(&mod->mkobj.kobj);
/* delay uevent until full sysfs population */
out:
return err;
}
static int mod_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params)
{
int err;
err = mod_sysfs_init(mod);
if (err)
goto out;
mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
if (!mod->holders_dir) {
err = -ENOMEM;
goto out_unreg;
}
err = module_param_sysfs_setup(mod, kparam, num_params);
if (err)
goto out_unreg_holders;
err = module_add_modinfo_attrs(mod);
if (err)
goto out_unreg_param;
add_usage_links(mod);
kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
return 0;
out_unreg_param:
module_param_sysfs_remove(mod);
out_unreg_holders:
kobject_put(mod->holders_dir);
out_unreg:
kobject_put(&mod->mkobj.kobj);
out:
return err;
}
static void mod_sysfs_fini(struct module *mod)
{
kobject_put(&mod->mkobj.kobj);
}
#else /* CONFIG_SYSFS */
static inline int mod_sysfs_init(struct module *mod)
{
return 0;
}
static inline int mod_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params)
{
return 0;
}
static inline int module_add_modinfo_attrs(struct module *mod)
{
return 0;
}
static inline void module_remove_modinfo_attrs(struct module *mod)
{
}
static void mod_sysfs_fini(struct module *mod)
{
}
static void del_usage_links(struct module *mod)
{
}
#endif /* CONFIG_SYSFS */
static void mod_kobject_remove(struct module *mod)
{
del_usage_links(mod);
module_remove_modinfo_attrs(mod);
module_param_sysfs_remove(mod);
kobject_put(mod->mkobj.drivers_dir);
kobject_put(mod->holders_dir);
mod_sysfs_fini(mod);
}
/*
* unlink the module with the whole machine is stopped with interrupts off
* - this defends against kallsyms not taking locks
*/
static int __unlink_module(void *_mod)
{
struct module *mod = _mod;
list_del(&mod->list);
return 0;
}
/* Free a module, remove from lists, etc. */
static void free_module(struct module *mod)
{
trace_module_free(mod);
/* Delete from various lists */
mutex_lock(&module_mutex);
stop_machine(__unlink_module, mod, NULL);
mutex_unlock(&module_mutex);
remove_notes_attrs(mod);
remove_sect_attrs(mod);
mod_kobject_remove(mod);
/* Arch-specific cleanup. */
module_arch_cleanup(mod);
/* Module unload stuff */
module_unload_free(mod);
/* Free any allocated parameters. */
destroy_params(mod->kp, mod->num_kp);
/* This may be NULL, but that's OK */
module_free(mod, mod->module_init);
kfree(mod->args);
percpu_modfree(mod);
#if defined(CONFIG_MODULE_UNLOAD)
if (mod->refptr)
free_percpu(mod->refptr);
#endif
/* Free lock-classes: */
lockdep_free_key_range(mod->module_core, mod->core_size);
/* Finally, free the core (containing the module structure) */
module_free(mod, mod->module_core);
#ifdef CONFIG_MPU
update_protections(current->mm);
#endif
}
void *__symbol_get(const char *symbol)
{
struct module *owner;
const struct kernel_symbol *sym;
preempt_disable();
sym = find_symbol(symbol, &owner, NULL, true, true);
if (sym && strong_try_module_get(owner))
sym = NULL;
preempt_enable();
return sym ? (void *)sym->value : NULL;
}
EXPORT_SYMBOL_GPL(__symbol_get);
/*
* Ensure that an exported symbol [global namespace] does not already exist
* in the kernel or in some other module's exported symbol table.
*
* You must hold the module_mutex.
*/
static int verify_export_symbols(struct module *mod)
{
unsigned int i;
struct module *owner;
const struct kernel_symbol *s;
struct {
const struct kernel_symbol *sym;
unsigned int num;
} arr[] = {
{ mod->syms, mod->num_syms },
{ mod->gpl_syms, mod->num_gpl_syms },
{ mod->gpl_future_syms, mod->num_gpl_future_syms },
#ifdef CONFIG_UNUSED_SYMBOLS
{ mod->unused_syms, mod->num_unused_syms },
{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
#endif
};
for (i = 0; i < ARRAY_SIZE(arr); i++) {
for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
if (find_symbol(s->name, &owner, NULL, true, false)) {
printk(KERN_ERR
"%s: exports duplicate symbol %s"
" (owned by %s)\n",
mod->name, s->name, module_name(owner));
return -ENOEXEC;
}
}
}
return 0;
}
/* Change all symbols so that st_value encodes the pointer directly. */
static int simplify_symbols(Elf_Shdr *sechdrs,
unsigned int symindex,
const char *strtab,
unsigned int versindex,
unsigned int pcpuindex,
struct module *mod)
{
Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
unsigned long secbase;
unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
int ret = 0;
const struct kernel_symbol *ksym;
for (i = 1; i < n; i++) {
switch (sym[i].st_shndx) {
case SHN_COMMON:
/* We compiled with -fno-common. These are not
supposed to happen. */
DEBUGP("Common symbol: %s\n", strtab + sym[i].st_name);
printk("%s: please compile with -fno-common\n",
mod->name);
ret = -ENOEXEC;
break;
case SHN_ABS:
/* Don't need to do anything */
DEBUGP("Absolute symbol: 0x%08lx\n",
(long)sym[i].st_value);
break;
case SHN_UNDEF:
ksym = resolve_symbol_wait(sechdrs, versindex,
strtab + sym[i].st_name,
mod);
/* Ok if resolved. */
if (ksym && !IS_ERR(ksym)) {
sym[i].st_value = ksym->value;
break;
}
/* Ok if weak. */
if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
break;
printk(KERN_WARNING "%s: Unknown symbol %s (err %li)\n",
mod->name, strtab + sym[i].st_name,
PTR_ERR(ksym));
ret = PTR_ERR(ksym) ?: -ENOENT;
break;
default:
/* Divert to percpu allocation if a percpu var. */
if (sym[i].st_shndx == pcpuindex)
secbase = (unsigned long)mod_percpu(mod);
else
secbase = sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase;
break;
}
}
return ret;
}
/* Additional bytes needed by arch in front of individual sections */
unsigned int __weak arch_mod_section_prepend(struct module *mod,
unsigned int section)
{
/* default implementation just returns zero */
return 0;
}
/* Update size with this section: return offset. */
static long get_offset(struct module *mod, unsigned int *size,
Elf_Shdr *sechdr, unsigned int section)
{
long ret;
*size += arch_mod_section_prepend(mod, section);
ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
*size = ret + sechdr->sh_size;
return ret;
}
/* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
might -- code, read-only data, read-write data, small data. Tally
sizes, and place the offsets into sh_entsize fields: high bit means it
belongs in init. */
static void layout_sections(struct module *mod,
const Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
const char *secstrings)
{
static unsigned long const masks[][2] = {
/* NOTE: all executable code must be the first section
* in this array; otherwise modify the text_size
* finder in the two loops below */
{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
{ SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
{ ARCH_SHF_SMALL | SHF_ALLOC, 0 }
};
unsigned int m, i;
for (i = 0; i < hdr->e_shnum; i++)
sechdrs[i].sh_entsize = ~0UL;
DEBUGP("Core section allocation order:\n");
for (m = 0; m < ARRAY_SIZE(masks); ++m) {
for (i = 0; i < hdr->e_shnum; ++i) {
Elf_Shdr *s = &sechdrs[i];
if ((s->sh_flags & masks[m][0]) != masks[m][0]
|| (s->sh_flags & masks[m][1])
|| s->sh_entsize != ~0UL
|| strstarts(secstrings + s->sh_name, ".init"))
continue;
s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
DEBUGP("\t%s\n", secstrings + s->sh_name);
}
if (m == 0)
mod->core_text_size = mod->core_size;
}
DEBUGP("Init section allocation order:\n");
for (m = 0; m < ARRAY_SIZE(masks); ++m) {
for (i = 0; i < hdr->e_shnum; ++i) {
Elf_Shdr *s = &sechdrs[i];
if ((s->sh_flags & masks[m][0]) != masks[m][0]
|| (s->sh_flags & masks[m][1])
|| s->sh_entsize != ~0UL
|| !strstarts(secstrings + s->sh_name, ".init"))
continue;
s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
| INIT_OFFSET_MASK);
DEBUGP("\t%s\n", secstrings + s->sh_name);
}
if (m == 0)
mod->init_text_size = mod->init_size;
}
}
static void set_license(struct module *mod, const char *license)
{
if (!license)
license = "unspecified";
if (!license_is_gpl_compatible(license)) {
if (!test_taint(TAINT_PROPRIETARY_MODULE))
printk(KERN_WARNING "%s: module license '%s' taints "
"kernel.\n", mod->name, license);
add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
}
}
/* Parse tag=value strings from .modinfo section */
static char *next_string(char *string, unsigned long *secsize)
{
/* Skip non-zero chars */
while (string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
/* Skip any zero padding. */
while (!string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
return string;
}
static char *get_modinfo(Elf_Shdr *sechdrs,
unsigned int info,
const char *tag)
{
char *p;
unsigned int taglen = strlen(tag);
unsigned long size = sechdrs[info].sh_size;
for (p = (char *)sechdrs[info].sh_addr; p; p = next_string(p, &size)) {
if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
return p + taglen + 1;
}
return NULL;
}
static void setup_modinfo(struct module *mod, Elf_Shdr *sechdrs,
unsigned int infoindex)
{
struct module_attribute *attr;
int i;
for (i = 0; (attr = modinfo_attrs[i]); i++) {
if (attr->setup)
attr->setup(mod,
get_modinfo(sechdrs,
infoindex,
attr->attr.name));
}
}
static void free_modinfo(struct module *mod)
{
struct module_attribute *attr;
int i;
for (i = 0; (attr = modinfo_attrs[i]); i++) {
if (attr->free)
attr->free(mod);
}
}
#ifdef CONFIG_KALLSYMS
/* lookup symbol in given range of kernel_symbols */
static const struct kernel_symbol *lookup_symbol(const char *name,
const struct kernel_symbol *start,
const struct kernel_symbol *stop)
{
const struct kernel_symbol *ks = start;
for (; ks < stop; ks++)
if (strcmp(ks->name, name) == 0)
return ks;
return NULL;
}
static int is_exported(const char *name, unsigned long value,
const struct module *mod)
{
const struct kernel_symbol *ks;
if (!mod)
ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
else
ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
return ks != NULL && ks->value == value;
}
/* As per nm */
static char elf_type(const Elf_Sym *sym,
Elf_Shdr *sechdrs,
const char *secstrings,
struct module *mod)
{
if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
return 'v';
else
return 'w';
}
if (sym->st_shndx == SHN_UNDEF)
return 'U';
if (sym->st_shndx == SHN_ABS)
return 'a';
if (sym->st_shndx >= SHN_LORESERVE)
return '?';
if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
return 't';
if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
&& sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
return 'r';
else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
return 'g';
else
return 'd';
}
if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
return 's';
else
return 'b';
}
if (strstarts(secstrings + sechdrs[sym->st_shndx].sh_name, ".debug"))
return 'n';
return '?';
}
static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
unsigned int shnum)
{
const Elf_Shdr *sec;
if (src->st_shndx == SHN_UNDEF
|| src->st_shndx >= shnum
|| !src->st_name)
return false;
sec = sechdrs + src->st_shndx;
if (!(sec->sh_flags & SHF_ALLOC)
#ifndef CONFIG_KALLSYMS_ALL
|| !(sec->sh_flags & SHF_EXECINSTR)
#endif
|| (sec->sh_entsize & INIT_OFFSET_MASK))
return false;
return true;
}
static unsigned long layout_symtab(struct module *mod,
Elf_Shdr *sechdrs,
unsigned int symindex,
unsigned int strindex,
const Elf_Ehdr *hdr,
const char *secstrings,
unsigned long *pstroffs,
unsigned long *strmap)
{
unsigned long symoffs;
Elf_Shdr *symsect = sechdrs + symindex;
Elf_Shdr *strsect = sechdrs + strindex;
const Elf_Sym *src;
const char *strtab;
unsigned int i, nsrc, ndst;
/* Put symbol section at end of init part of module. */
symsect->sh_flags |= SHF_ALLOC;
symsect->sh_entsize = get_offset(mod, &mod->init_size, symsect,
symindex) | INIT_OFFSET_MASK;
DEBUGP("\t%s\n", secstrings + symsect->sh_name);
src = (void *)hdr + symsect->sh_offset;
nsrc = symsect->sh_size / sizeof(*src);
strtab = (void *)hdr + strsect->sh_offset;
for (ndst = i = 1; i < nsrc; ++i, ++src)
if (is_core_symbol(src, sechdrs, hdr->e_shnum)) {
unsigned int j = src->st_name;
while(!__test_and_set_bit(j, strmap) && strtab[j])
++j;
++ndst;
}
/* Append room for core symbols at end of core part. */
symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
mod->core_size = symoffs + ndst * sizeof(Elf_Sym);
/* Put string table section at end of init part of module. */
strsect->sh_flags |= SHF_ALLOC;
strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
strindex) | INIT_OFFSET_MASK;
DEBUGP("\t%s\n", secstrings + strsect->sh_name);
/* Append room for core symbols' strings at end of core part. */
*pstroffs = mod->core_size;
__set_bit(0, strmap);
mod->core_size += bitmap_weight(strmap, strsect->sh_size);
return symoffs;
}
static void add_kallsyms(struct module *mod,
Elf_Shdr *sechdrs,
unsigned int shnum,
unsigned int symindex,
unsigned int strindex,
unsigned long symoffs,
unsigned long stroffs,
const char *secstrings,
unsigned long *strmap)
{
unsigned int i, ndst;
const Elf_Sym *src;
Elf_Sym *dst;
char *s;
mod->symtab = (void *)sechdrs[symindex].sh_addr;
mod->num_symtab = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
mod->strtab = (void *)sechdrs[strindex].sh_addr;
/* Set types up while we still have access to sections. */
for (i = 0; i < mod->num_symtab; i++)
mod->symtab[i].st_info
= elf_type(&mod->symtab[i], sechdrs, secstrings, mod);
mod->core_symtab = dst = mod->module_core + symoffs;
src = mod->symtab;
*dst = *src;
for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) {
if (!is_core_symbol(src, sechdrs, shnum))
continue;
dst[ndst] = *src;
dst[ndst].st_name = bitmap_weight(strmap, dst[ndst].st_name);
++ndst;
}
mod->core_num_syms = ndst;
mod->core_strtab = s = mod->module_core + stroffs;
for (*s = 0, i = 1; i < sechdrs[strindex].sh_size; ++i)
if (test_bit(i, strmap))
*++s = mod->strtab[i];
}
#else
static inline unsigned long layout_symtab(struct module *mod,
Elf_Shdr *sechdrs,
unsigned int symindex,
unsigned int strindex,
const Elf_Ehdr *hdr,
const char *secstrings,
unsigned long *pstroffs,
unsigned long *strmap)
{
return 0;
}
static inline void add_kallsyms(struct module *mod,
Elf_Shdr *sechdrs,
unsigned int shnum,
unsigned int symindex,
unsigned int strindex,
unsigned long symoffs,
unsigned long stroffs,
const char *secstrings,
const unsigned long *strmap)
{
}
#endif /* CONFIG_KALLSYMS */
static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
{
#ifdef CONFIG_DYNAMIC_DEBUG
if (ddebug_add_module(debug, num, debug->modname))
printk(KERN_ERR "dynamic debug error adding module: %s\n",
debug->modname);
#endif
}
static void *module_alloc_update_bounds(unsigned long size)
{
void *ret = module_alloc(size);
if (ret) {
mutex_lock(&module_mutex);
/* Update module bounds. */
if ((unsigned long)ret < module_addr_min)
module_addr_min = (unsigned long)ret;
if ((unsigned long)ret + size > module_addr_max)
module_addr_max = (unsigned long)ret + size;
mutex_unlock(&module_mutex);
}
return ret;
}
#ifdef CONFIG_DEBUG_KMEMLEAK
static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
Elf_Shdr *sechdrs, char *secstrings)
{
unsigned int i;
/* only scan the sections containing data */
kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
for (i = 1; i < hdr->e_shnum; i++) {
if (!(sechdrs[i].sh_flags & SHF_ALLOC))
continue;
if (strncmp(secstrings + sechdrs[i].sh_name, ".data", 5) != 0
&& strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) != 0)
continue;
kmemleak_scan_area((void *)sechdrs[i].sh_addr,
sechdrs[i].sh_size, GFP_KERNEL);
}
}
#else
static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
Elf_Shdr *sechdrs, char *secstrings)
{
}
#endif
/* Allocate and load the module: note that size of section 0 is always
zero, and we rely on this for optional sections. */
static noinline struct module *load_module(void __user *umod,
unsigned long len,
const char __user *uargs)
{
Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
char *secstrings, *args, *modmagic, *strtab = NULL;
char *staging;
unsigned int i;
unsigned int symindex = 0;
unsigned int strindex = 0;
unsigned int modindex, versindex, infoindex, pcpuindex;
struct module *mod;
long err = 0;
void *ptr = NULL; /* Stops spurious gcc warning */
unsigned long symoffs, stroffs, *strmap;
void __percpu *percpu;
mm_segment_t old_fs;
DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
umod, len, uargs);
if (len < sizeof(*hdr))
return ERR_PTR(-ENOEXEC);
/* Suck in entire file: we'll want most of it. */
/* vmalloc barfs on "unusual" numbers. Check here */
if (len > 64 * 1024 * 1024 || (hdr = vmalloc(len)) == NULL)
return ERR_PTR(-ENOMEM);
if (copy_from_user(hdr, umod, len) != 0) {
err = -EFAULT;
goto free_hdr;
}
/* Sanity checks against insmoding binaries or wrong arch,
weird elf version */
if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
|| hdr->e_type != ET_REL
|| !elf_check_arch(hdr)
|| hdr->e_shentsize != sizeof(*sechdrs)) {
err = -ENOEXEC;
goto free_hdr;
}
if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr))
goto truncated;
/* Convenience variables */
sechdrs = (void *)hdr + hdr->e_shoff;
secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
sechdrs[0].sh_addr = 0;
for (i = 1; i < hdr->e_shnum; i++) {
if (sechdrs[i].sh_type != SHT_NOBITS
&& len < sechdrs[i].sh_offset + sechdrs[i].sh_size)
goto truncated;
/* Mark all sections sh_addr with their address in the
temporary image. */
sechdrs[i].sh_addr = (size_t)hdr + sechdrs[i].sh_offset;
/* Internal symbols and strings. */
if (sechdrs[i].sh_type == SHT_SYMTAB) {
symindex = i;
strindex = sechdrs[i].sh_link;
strtab = (char *)hdr + sechdrs[strindex].sh_offset;
}
#ifndef CONFIG_MODULE_UNLOAD
/* Don't load .exit sections */
if (strstarts(secstrings+sechdrs[i].sh_name, ".exit"))
sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
#endif
}
modindex = find_sec(hdr, sechdrs, secstrings,
".gnu.linkonce.this_module");
if (!modindex) {
printk(KERN_WARNING "No module found in object\n");
err = -ENOEXEC;
goto free_hdr;
}
/* This is temporary: point mod into copy of data. */
mod = (void *)sechdrs[modindex].sh_addr;
if (symindex == 0) {
printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
mod->name);
err = -ENOEXEC;
goto free_hdr;
}
versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);
/* Don't keep modinfo and version sections. */
sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
/* Check module struct version now, before we try to use module. */
if (!check_modstruct_version(sechdrs, versindex, mod)) {
err = -ENOEXEC;
goto free_hdr;
}
modmagic = get_modinfo(sechdrs, infoindex, "vermagic");
/* This is allowed: modprobe --force will invalidate it. */
if (!modmagic) {
err = try_to_force_load(mod, "bad vermagic");
if (err)
goto free_hdr;
} else if (!same_magic(modmagic, vermagic, versindex)) {
printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
mod->name, modmagic, vermagic);
err = -ENOEXEC;
goto free_hdr;
}
staging = get_modinfo(sechdrs, infoindex, "staging");
if (staging) {
add_taint_module(mod, TAINT_CRAP);
printk(KERN_WARNING "%s: module is from the staging directory,"
" the quality is unknown, you have been warned.\n",
mod->name);
}
/* Now copy in args */
args = strndup_user(uargs, ~0UL >> 1);
if (IS_ERR(args)) {
err = PTR_ERR(args);
goto free_hdr;
}
strmap = kzalloc(BITS_TO_LONGS(sechdrs[strindex].sh_size)
* sizeof(long), GFP_KERNEL);
if (!strmap) {
err = -ENOMEM;
goto free_mod;
}
mod->state = MODULE_STATE_COMING;
/* Allow arches to frob section contents and sizes. */
err = module_frob_arch_sections(hdr, sechdrs, secstrings, mod);
if (err < 0)
goto free_mod;
if (pcpuindex) {
/* We have a special allocation for this section. */
err = percpu_modalloc(mod, sechdrs[pcpuindex].sh_size,
sechdrs[pcpuindex].sh_addralign);
if (err)
goto free_mod;
sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
}
/* Keep this around for failure path. */
percpu = mod_percpu(mod);
/* Determine total sizes, and put offsets in sh_entsize. For now
this is done generically; there doesn't appear to be any
special cases for the architectures. */
layout_sections(mod, hdr, sechdrs, secstrings);
symoffs = layout_symtab(mod, sechdrs, symindex, strindex, hdr,
secstrings, &stroffs, strmap);
/* Do the allocs. */
ptr = module_alloc_update_bounds(mod->core_size);
/*
* The pointer to this block is stored in the module structure
* which is inside the block. Just mark it as not being a
* leak.
*/
kmemleak_not_leak(ptr);
if (!ptr) {
err = -ENOMEM;
goto free_percpu;
}
memset(ptr, 0, mod->core_size);
mod->module_core = ptr;
ptr = module_alloc_update_bounds(mod->init_size);
/*
* The pointer to this block is stored in the module structure
* which is inside the block. This block doesn't need to be
* scanned as it contains data and code that will be freed
* after the module is initialized.
*/
kmemleak_ignore(ptr);
if (!ptr && mod->init_size) {
err = -ENOMEM;
goto free_core;
}
memset(ptr, 0, mod->init_size);
mod->module_init = ptr;
/* Transfer each section which specifies SHF_ALLOC */
DEBUGP("final section addresses:\n");
for (i = 0; i < hdr->e_shnum; i++) {
void *dest;
if (!(sechdrs[i].sh_flags & SHF_ALLOC))
continue;
if (sechdrs[i].sh_entsize & INIT_OFFSET_MASK)
dest = mod->module_init
+ (sechdrs[i].sh_entsize & ~INIT_OFFSET_MASK);
else
dest = mod->module_core + sechdrs[i].sh_entsize;
if (sechdrs[i].sh_type != SHT_NOBITS)
memcpy(dest, (void *)sechdrs[i].sh_addr,
sechdrs[i].sh_size);
/* Update sh_addr to point to copy in image. */
sechdrs[i].sh_addr = (unsigned long)dest;
DEBUGP("\t0x%lx %s\n", sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name);
}
/* Module has been moved. */
mod = (void *)sechdrs[modindex].sh_addr;
kmemleak_load_module(mod, hdr, sechdrs, secstrings);
#if defined(CONFIG_MODULE_UNLOAD)
mod->refptr = alloc_percpu(struct module_ref);
if (!mod->refptr) {
err = -ENOMEM;
goto free_init;
}
#endif
/* Now we've moved module, initialize linked lists, etc. */
module_unload_init(mod);
/* Set up license info based on the info section */
set_license(mod, get_modinfo(sechdrs, infoindex, "license"));
/*
* ndiswrapper is under GPL by itself, but loads proprietary modules.
* Don't use add_taint_module(), as it would prevent ndiswrapper from
* using GPL-only symbols it needs.
*/
if (strcmp(mod->name, "ndiswrapper") == 0)
add_taint(TAINT_PROPRIETARY_MODULE);
/* driverloader was caught wrongly pretending to be under GPL */
if (strcmp(mod->name, "driverloader") == 0)
add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
/* Set up MODINFO_ATTR fields */
setup_modinfo(mod, sechdrs, infoindex);
/* Fix up syms, so that st_value is a pointer to location. */
err = simplify_symbols(sechdrs, symindex, strtab, versindex, pcpuindex,
mod);
if (err < 0)
goto cleanup;
/* Now we've got everything in the final locations, we can
* find optional sections. */
mod->kp = section_objs(hdr, sechdrs, secstrings, "__param",
sizeof(*mod->kp), &mod->num_kp);
mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",
sizeof(*mod->syms), &mod->num_syms);
mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");
mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",
sizeof(*mod->gpl_syms),
&mod->num_gpl_syms);
mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");
mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,
"__ksymtab_gpl_future",
sizeof(*mod->gpl_future_syms),
&mod->num_gpl_future_syms);
mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,
"__kcrctab_gpl_future");
#ifdef CONFIG_UNUSED_SYMBOLS
mod->unused_syms = section_objs(hdr, sechdrs, secstrings,
"__ksymtab_unused",
sizeof(*mod->unused_syms),
&mod->num_unused_syms);
mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,
"__kcrctab_unused");
mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,
"__ksymtab_unused_gpl",
sizeof(*mod->unused_gpl_syms),
&mod->num_unused_gpl_syms);
mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,
"__kcrctab_unused_gpl");
#endif
#ifdef CONFIG_CONSTRUCTORS
mod->ctors = section_objs(hdr, sechdrs, secstrings, ".ctors",
sizeof(*mod->ctors), &mod->num_ctors);
#endif
#ifdef CONFIG_TRACEPOINTS
mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
"__tracepoints",
sizeof(*mod->tracepoints),
&mod->num_tracepoints);
#endif
#ifdef CONFIG_EVENT_TRACING
mod->trace_events = section_objs(hdr, sechdrs, secstrings,
"_ftrace_events",
sizeof(*mod->trace_events),
&mod->num_trace_events);
/*
* This section contains pointers to allocated objects in the trace
* code and not scanning it leads to false positives.
*/
kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
mod->num_trace_events, GFP_KERNEL);
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
/* sechdrs[0].sh_size is always zero */
mod->ftrace_callsites = section_objs(hdr, sechdrs, secstrings,
"__mcount_loc",
sizeof(*mod->ftrace_callsites),
&mod->num_ftrace_callsites);
#endif
#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !mod->crcs)
|| (mod->num_gpl_syms && !mod->gpl_crcs)
|| (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
#ifdef CONFIG_UNUSED_SYMBOLS
|| (mod->num_unused_syms && !mod->unused_crcs)
|| (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
#endif
) {
err = try_to_force_load(mod,
"no versions for exported symbols");
if (err)
goto cleanup;
}
#endif
/* Now do relocations. */
for (i = 1; i < hdr->e_shnum; i++) {
const char *strtab = (char *)sechdrs[strindex].sh_addr;
unsigned int info = sechdrs[i].sh_info;
/* Not a valid relocation section? */
if (info >= hdr->e_shnum)
continue;
/* Don't bother with non-allocated sections */
if (!(sechdrs[info].sh_flags & SHF_ALLOC))
continue;
if (sechdrs[i].sh_type == SHT_REL)
err = apply_relocate(sechdrs, strtab, symindex, i,mod);
else if (sechdrs[i].sh_type == SHT_RELA)
err = apply_relocate_add(sechdrs, strtab, symindex, i,
mod);
if (err < 0)
goto cleanup;
}
/* Set up and sort exception table */
mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);
sort_extable(mod->extable, mod->extable + mod->num_exentries);
/* Finally, copy percpu area over. */
percpu_modcopy(mod, (void *)sechdrs[pcpuindex].sh_addr,
sechdrs[pcpuindex].sh_size);
add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex,
symoffs, stroffs, secstrings, strmap);
kfree(strmap);
strmap = NULL;
if (!mod->taints) {
struct _ddebug *debug;
unsigned int num_debug;
debug = section_objs(hdr, sechdrs, secstrings, "__verbose",
sizeof(*debug), &num_debug);
if (debug)
dynamic_debug_setup(debug, num_debug);
}
err = module_finalize(hdr, sechdrs, mod);
if (err < 0)
goto cleanup;
/* flush the icache in correct context */
old_fs = get_fs();
set_fs(KERNEL_DS);
/*
* Flush the instruction cache, since we've played with text.
* Do it before processing of module parameters, so the module
* can provide parameter accessor functions of its own.
*/
if (mod->module_init)
flush_icache_range((unsigned long)mod->module_init,
(unsigned long)mod->module_init
+ mod->init_size);
flush_icache_range((unsigned long)mod->module_core,
(unsigned long)mod->module_core + mod->core_size);
set_fs(old_fs);
mod->args = args;
if (section_addr(hdr, sechdrs, secstrings, "__obsparm"))
printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
mod->name);
/* Now sew it into the lists so we can get lockdep and oops
* info during argument parsing. Noone should access us, since
* strong_try_module_get() will fail.
* lockdep/oops can run asynchronous, so use the RCU list insertion
* function to insert in a way safe to concurrent readers.
* The mutex protects against concurrent writers.
*/
mutex_lock(&module_mutex);
if (find_module(mod->name)) {
err = -EEXIST;
goto unlock;
}
/* Find duplicate symbols */
err = verify_export_symbols(mod);
if (err < 0)
goto unlock;
list_add_rcu(&mod->list, &modules);
mutex_unlock(&module_mutex);
err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp, NULL);
if (err < 0)
goto unlink;
err = mod_sysfs_setup(mod, mod->kp, mod->num_kp);
if (err < 0)
goto unlink;
add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
/* Get rid of temporary copy */
vfree(hdr);
trace_module_load(mod);
/* Done! */
return mod;
unlink:
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
unlock:
mutex_unlock(&module_mutex);
synchronize_sched();
module_arch_cleanup(mod);
cleanup:
free_modinfo(mod);
module_unload_free(mod);
#if defined(CONFIG_MODULE_UNLOAD)
free_percpu(mod->refptr);
free_init:
#endif
module_free(mod, mod->module_init);
free_core:
module_free(mod, mod->module_core);
/* mod will be freed with core. Don't access it beyond this line! */
free_percpu:
free_percpu(percpu);
free_mod:
kfree(args);
kfree(strmap);
free_hdr:
vfree(hdr);
return ERR_PTR(err);
truncated:
printk(KERN_ERR "Module len %lu truncated\n", len);
err = -ENOEXEC;
goto free_hdr;
}
/* Call module constructors. */
static void do_mod_ctors(struct module *mod)
{
#ifdef CONFIG_CONSTRUCTORS
unsigned long i;
for (i = 0; i < mod->num_ctors; i++)
mod->ctors[i]();
#endif
}
/* This is where the real work happens */
SYSCALL_DEFINE3(init_module, void __user *, umod,
unsigned long, len, const char __user *, uargs)
{
struct module *mod;
int ret = 0;
/* Must have permission */
if (!capable(CAP_SYS_MODULE) || modules_disabled)
return -EPERM;
/* Do all the hard work */
mod = load_module(umod, len, uargs);
if (IS_ERR(mod))
return PTR_ERR(mod);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_COMING, mod);
do_mod_ctors(mod);
/* Start the module */
if (mod->init != NULL)
ret = do_one_initcall(mod->init);
if (ret < 0) {
/* Init routine failed: abort. Try to protect us from
buggy refcounters. */
mod->state = MODULE_STATE_GOING;
synchronize_sched();
module_put(mod);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
free_module(mod);
wake_up(&module_wq);
return ret;
}
if (ret > 0) {
printk(KERN_WARNING
"%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n"
"%s: loading module anyway...\n",
__func__, mod->name, ret,
__func__);
dump_stack();
}
/* Now it's a first class citizen! Wake up anyone waiting for it. */
mod->state = MODULE_STATE_LIVE;
wake_up(&module_wq);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_LIVE, mod);
/* We need to finish all async code before the module init sequence is done */
async_synchronize_full();
mutex_lock(&module_mutex);
/* Drop initial reference. */
module_put(mod);
trim_init_extable(mod);
#ifdef CONFIG_KALLSYMS
mod->num_symtab = mod->core_num_syms;
mod->symtab = mod->core_symtab;
mod->strtab = mod->core_strtab;
#endif
module_free(mod, mod->module_init);
mod->module_init = NULL;
mod->init_size = 0;
mod->init_text_size = 0;
mutex_unlock(&module_mutex);
return 0;
}
static inline int within(unsigned long addr, void *start, unsigned long size)
{
return ((void *)addr >= start && (void *)addr < start + size);
}
#ifdef CONFIG_KALLSYMS
/*
* This ignores the intensely annoying "mapping symbols" found
* in ARM ELF files: $a, $t and $d.
*/
static inline int is_arm_mapping_symbol(const char *str)
{
return str[0] == '$' && strchr("atd", str[1])
&& (str[2] == '\0' || str[2] == '.');
}
static const char *get_ksymbol(struct module *mod,
unsigned long addr,
unsigned long *size,
unsigned long *offset)
{
unsigned int i, best = 0;
unsigned long nextval;
/* At worse, next value is at end of module */
if (within_module_init(addr, mod))
nextval = (unsigned long)mod->module_init+mod->init_text_size;
else
nextval = (unsigned long)mod->module_core+mod->core_text_size;
/* Scan for closest preceeding symbol, and next symbol. (ELF
starts real symbols at 1). */
for (i = 1; i < mod->num_symtab; i++) {
if (mod->symtab[i].st_shndx == SHN_UNDEF)
continue;
/* We ignore unnamed symbols: they're uninformative
* and inserted at a whim. */
if (mod->symtab[i].st_value <= addr
&& mod->symtab[i].st_value > mod->symtab[best].st_value
&& *(mod->strtab + mod->symtab[i].st_name) != '\0'
&& !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
best = i;
if (mod->symtab[i].st_value > addr
&& mod->symtab[i].st_value < nextval
&& *(mod->strtab + mod->symtab[i].st_name) != '\0'
&& !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
nextval = mod->symtab[i].st_value;
}
if (!best)
return NULL;
if (size)
*size = nextval - mod->symtab[best].st_value;
if (offset)
*offset = addr - mod->symtab[best].st_value;
return mod->strtab + mod->symtab[best].st_name;
}
/* For kallsyms to ask for address resolution. NULL means not found. Careful
* not to lock to avoid deadlock on oopses, simply disable preemption. */
const char *module_address_lookup(unsigned long addr,
unsigned long *size,
unsigned long *offset,
char **modname,
char *namebuf)
{
struct module *mod;
const char *ret = NULL;
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
if (modname)
*modname = mod->name;
ret = get_ksymbol(mod, addr, size, offset);
break;
}
}
/* Make a copy in here where it's safe */
if (ret) {
strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
ret = namebuf;
}
preempt_enable();
return ret;
}
int lookup_module_symbol_name(unsigned long addr, char *symname)
{
struct module *mod;
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
const char *sym;
sym = get_ksymbol(mod, addr, NULL, NULL);
if (!sym)
goto out;
strlcpy(symname, sym, KSYM_NAME_LEN);
preempt_enable();
return 0;
}
}
out:
preempt_enable();
return -ERANGE;
}
int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
unsigned long *offset, char *modname, char *name)
{
struct module *mod;
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
if (within_module_init(addr, mod) ||
within_module_core(addr, mod)) {
const char *sym;
sym = get_ksymbol(mod, addr, size, offset);
if (!sym)
goto out;
if (modname)
strlcpy(modname, mod->name, MODULE_NAME_LEN);
if (name)
strlcpy(name, sym, KSYM_NAME_LEN);
preempt_enable();
return 0;
}
}
out:
preempt_enable();
return -ERANGE;
}
int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
char *name, char *module_name, int *exported)
{
struct module *mod;
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
if (symnum < mod->num_symtab) {
*value = mod->symtab[symnum].st_value;
*type = mod->symtab[symnum].st_info;
strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
KSYM_NAME_LEN);
strlcpy(module_name, mod->name, MODULE_NAME_LEN);
*exported = is_exported(name, *value, mod);
preempt_enable();
return 0;
}
symnum -= mod->num_symtab;
}
preempt_enable();
return -ERANGE;
}
static unsigned long mod_find_symname(struct module *mod, const char *name)
{
unsigned int i;
for (i = 0; i < mod->num_symtab; i++)
if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
mod->symtab[i].st_info != 'U')
return mod->symtab[i].st_value;
return 0;
}
/* Look for this name: can be of form module:name. */
unsigned long module_kallsyms_lookup_name(const char *name)
{
struct module *mod;
char *colon;
unsigned long ret = 0;
/* Don't lock: we're in enough trouble already. */
preempt_disable();
if ((colon = strchr(name, ':')) != NULL) {
*colon = '\0';
if ((mod = find_module(name)) != NULL)
ret = mod_find_symname(mod, colon+1);
*colon = ':';
} else {
list_for_each_entry_rcu(mod, &modules, list)
if ((ret = mod_find_symname(mod, name)) != 0)
break;
}
preempt_enable();
return ret;
}
int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
struct module *, unsigned long),
void *data)
{
struct module *mod;
unsigned int i;
int ret;
list_for_each_entry(mod, &modules, list) {
for (i = 0; i < mod->num_symtab; i++) {
ret = fn(data, mod->strtab + mod->symtab[i].st_name,
mod, mod->symtab[i].st_value);
if (ret != 0)
return ret;
}
}
return 0;
}
#endif /* CONFIG_KALLSYMS */
static char *module_flags(struct module *mod, char *buf)
{
int bx = 0;
if (mod->taints ||
mod->state == MODULE_STATE_GOING ||
mod->state == MODULE_STATE_COMING) {
buf[bx++] = '(';
if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
buf[bx++] = 'P';
if (mod->taints & (1 << TAINT_FORCED_MODULE))
buf[bx++] = 'F';
if (mod->taints & (1 << TAINT_CRAP))
buf[bx++] = 'C';
/*
* TAINT_FORCED_RMMOD: could be added.
* TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
* apply to modules.
*/
/* Show a - for module-is-being-unloaded */
if (mod->state == MODULE_STATE_GOING)
buf[bx++] = '-';
/* Show a + for module-is-being-loaded */
if (mod->state == MODULE_STATE_COMING)
buf[bx++] = '+';
buf[bx++] = ')';
}
buf[bx] = '\0';
return buf;
}
#ifdef CONFIG_PROC_FS
/* Called by the /proc file system to return a list of modules. */
static void *m_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&module_mutex);
return seq_list_start(&modules, *pos);
}
static void *m_next(struct seq_file *m, void *p, loff_t *pos)
{
return seq_list_next(p, &modules, pos);
}
static void m_stop(struct seq_file *m, void *p)
{
mutex_unlock(&module_mutex);
}
static int m_show(struct seq_file *m, void *p)
{
struct module *mod = list_entry(p, struct module, list);
char buf[8];
seq_printf(m, "%s %u",
mod->name, mod->init_size + mod->core_size);
print_unload_info(m, mod);
/* Informative for users. */
seq_printf(m, " %s",
mod->state == MODULE_STATE_GOING ? "Unloading":
mod->state == MODULE_STATE_COMING ? "Loading":
"Live");
/* Used by oprofile and other similar tools. */
seq_printf(m, " 0x%p", mod->module_core);
/* Taints info */
if (mod->taints)
seq_printf(m, " %s", module_flags(mod, buf));
seq_printf(m, "\n");
return 0;
}
/* Format: modulename size refcount deps address
Where refcount is a number or -, and deps is a comma-separated list
of depends or -.
*/
static const struct seq_operations modules_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = m_show
};
static int modules_open(struct inode *inode, struct file *file)
{
return seq_open(file, &modules_op);
}
static const struct file_operations proc_modules_operations = {
.open = modules_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init proc_modules_init(void)
{
proc_create("modules", 0, NULL, &proc_modules_operations);
return 0;
}
module_init(proc_modules_init);
#endif
/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_extables(unsigned long addr)
{
const struct exception_table_entry *e = NULL;
struct module *mod;
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
if (mod->num_exentries == 0)
continue;
e = search_extable(mod->extable,
mod->extable + mod->num_exentries - 1,
addr);
if (e)
break;
}
preempt_enable();
/* Now, if we found one, we are running inside it now, hence
we cannot unload the module, hence no refcnt needed. */
return e;
}
/*
* is_module_address - is this address inside a module?
* @addr: the address to check.
*
* See is_module_text_address() if you simply want to see if the address
* is code (not data).
*/
bool is_module_address(unsigned long addr)
{
bool ret;
preempt_disable();
ret = __module_address(addr) != NULL;
preempt_enable();
return ret;
}
/*
* __module_address - get the module which contains an address.
* @addr: the address.
*
* Must be called with preempt disabled or module mutex held so that
* module doesn't get freed during this.
*/
struct module *__module_address(unsigned long addr)
{
struct module *mod;
if (addr < module_addr_min || addr > module_addr_max)
return NULL;
list_for_each_entry_rcu(mod, &modules, list)
if (within_module_core(addr, mod)
|| within_module_init(addr, mod))
return mod;
return NULL;
}
EXPORT_SYMBOL_GPL(__module_address);
/*
* is_module_text_address - is this address inside module code?
* @addr: the address to check.
*
* See is_module_address() if you simply want to see if the address is
* anywhere in a module. See kernel_text_address() for testing if an
* address corresponds to kernel or module code.
*/
bool is_module_text_address(unsigned long addr)
{
bool ret;
preempt_disable();
ret = __module_text_address(addr) != NULL;
preempt_enable();
return ret;
}
/*
* __module_text_address - get the module whose code contains an address.
* @addr: the address.
*
* Must be called with preempt disabled or module mutex held so that
* module doesn't get freed during this.
*/
struct module *__module_text_address(unsigned long addr)
{
struct module *mod = __module_address(addr);
if (mod) {
/* Make sure it's within the text section. */
if (!within(addr, mod->module_init, mod->init_text_size)
&& !within(addr, mod->module_core, mod->core_text_size))
mod = NULL;
}
return mod;
}
EXPORT_SYMBOL_GPL(__module_text_address);
/* Don't grab lock, we're oopsing. */
void print_modules(void)
{
struct module *mod;
char buf[8];
printk(KERN_DEFAULT "Modules linked in:");
/* Most callers should already have preempt disabled, but make sure */
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list)
printk(" %s%s", mod->name, module_flags(mod, buf));
preempt_enable();
if (last_unloaded_module[0])
printk(" [last unloaded: %s]", last_unloaded_module);
printk("\n");
}
#ifdef CONFIG_MODVERSIONS
/* Generate the signature for all relevant module structures here.
* If these change, we don't want to try to parse the module. */
void module_layout(struct module *mod,
struct modversion_info *ver,
struct kernel_param *kp,
struct kernel_symbol *ks,
struct tracepoint *tp)
{
}
EXPORT_SYMBOL(module_layout);
#endif
#ifdef CONFIG_TRACEPOINTS
void module_update_tracepoints(void)
{
struct module *mod;
mutex_lock(&module_mutex);
list_for_each_entry(mod, &modules, list)
if (!mod->taints)
tracepoint_update_probe_range(mod->tracepoints,
mod->tracepoints + mod->num_tracepoints);
mutex_unlock(&module_mutex);
}
/*
* Returns 0 if current not found.
* Returns 1 if current found.
*/
int module_get_iter_tracepoints(struct tracepoint_iter *iter)
{
struct module *iter_mod;
int found = 0;
mutex_lock(&module_mutex);
list_for_each_entry(iter_mod, &modules, list) {
if (!iter_mod->taints) {
/*
* Sorted module list
*/
if (iter_mod < iter->module)
continue;
else if (iter_mod > iter->module)
iter->tracepoint = NULL;
found = tracepoint_get_iter_range(&iter->tracepoint,
iter_mod->tracepoints,
iter_mod->tracepoints
+ iter_mod->num_tracepoints);
if (found) {
iter->module = iter_mod;
break;
}
}
}
mutex_unlock(&module_mutex);
return found;
}
#endif
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