[PATCH] Auto size the per cpu area.

[linux-2.6/kmemtrace.git] / kernel / module.c

/*
   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/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/elf.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/stop_machine.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/mutex.h>
#include <linux/unwind.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
#include <asm/cacheflush.h>
#include <linux/license.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))

/* Protects module list */
static DEFINE_SPINLOCK(modlist_lock);

/* List of modules, protected by module_mutex AND modlist_lock */
static DEFINE_MUTEX(module_mutex);
static LIST_HEAD(modules);

static BLOCKING_NOTIFIER_HEAD(module_notify_list);

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() */
static inline int strong_try_module_get(struct module *mod)
{
        if (mod && mod->state == MODULE_STATE_COMING)
                return 0;
        return try_module_get(mod);
}

/* A thread that wants to hold a reference to a module only while it
 * is running can call ths 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;
}

/* 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 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 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[];
extern const unsigned long __start___kcrctab_unused[];
extern const unsigned long __start___kcrctab_unused_gpl[];

#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
#else
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
#endif

/* 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 void printk_unused_warning(const char *name)
{
        printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
                "however this module is using it.\n", 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");
}

/* Find a symbol, return value, crc and module which owns it */
static unsigned long __find_symbol(const char *name,
                                   struct module **owner,
                                   const unsigned long **crc,
                                   int gplok)
{
        struct module *mod;
        const struct kernel_symbol *ks;

        /* Core kernel first. */ 
        *owner = NULL;
        ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
        if (ks) {
                *crc = symversion(__start___kcrctab, (ks - __start___ksymtab));
                return ks->value;
        }
        if (gplok) {
                ks = lookup_symbol(name, __start___ksymtab_gpl,
                                         __stop___ksymtab_gpl);
                if (ks) {
                        *crc = symversion(__start___kcrctab_gpl,
                                          (ks - __start___ksymtab_gpl));
                        return ks->value;
                }
        }
        ks = lookup_symbol(name, __start___ksymtab_gpl_future,
                                 __stop___ksymtab_gpl_future);
        if (ks) {
                if (!gplok) {
                        printk(KERN_WARNING "Symbol %s is being used "
                               "by a non-GPL module, which will not "
                               "be allowed in the future\n", name);
                        printk(KERN_WARNING "Please see the file "
                               "Documentation/feature-removal-schedule.txt "
                               "in the kernel source tree for more "
                               "details.\n");
                }
                *crc = symversion(__start___kcrctab_gpl_future,
                                  (ks - __start___ksymtab_gpl_future));
                return ks->value;
        }

        ks = lookup_symbol(name, __start___ksymtab_unused,
                                 __stop___ksymtab_unused);
        if (ks) {
                printk_unused_warning(name);
                *crc = symversion(__start___kcrctab_unused,
                                  (ks - __start___ksymtab_unused));
                return ks->value;
        }

        if (gplok)
                ks = lookup_symbol(name, __start___ksymtab_unused_gpl,
                                 __stop___ksymtab_unused_gpl);
        if (ks) {
                printk_unused_warning(name);
                *crc = symversion(__start___kcrctab_unused_gpl,
                                  (ks - __start___ksymtab_unused_gpl));
                return ks->value;
        }

        /* Now try modules. */ 
        list_for_each_entry(mod, &modules, list) {
                *owner = mod;
                ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
                if (ks) {
                        *crc = symversion(mod->crcs, (ks - mod->syms));
                        return ks->value;
                }

                if (gplok) {
                        ks = lookup_symbol(name, mod->gpl_syms,
                                           mod->gpl_syms + mod->num_gpl_syms);
                        if (ks) {
                                *crc = symversion(mod->gpl_crcs,
                                                  (ks - mod->gpl_syms));
                                return ks->value;
                        }
                }
                ks = lookup_symbol(name, mod->unused_syms, mod->unused_syms + mod->num_unused_syms);
                if (ks) {
                        printk_unused_warning(name);
                        *crc = symversion(mod->unused_crcs, (ks - mod->unused_syms));
                        return ks->value;
                }

                if (gplok) {
                        ks = lookup_symbol(name, mod->unused_gpl_syms,
                                           mod->unused_gpl_syms + mod->num_unused_gpl_syms);
                        if (ks) {
                                printk_unused_warning(name);
                                *crc = symversion(mod->unused_gpl_crcs,
                                                  (ks - mod->unused_gpl_syms));
                                return ks->value;
                        }
                }
                ks = lookup_symbol(name, mod->gpl_future_syms,
                                   (mod->gpl_future_syms +
                                    mod->num_gpl_future_syms));
                if (ks) {
                        if (!gplok) {
                                printk(KERN_WARNING "Symbol %s is being used "
                                       "by a non-GPL module, which will not "
                                       "be allowed in the future\n", name);
                                printk(KERN_WARNING "Please see the file "
                                       "Documentation/feature-removal-schedule.txt "
                                       "in the kernel source tree for more "
                                       "details.\n");
                        }
                        *crc = symversion(mod->gpl_future_crcs,
                                          (ks - mod->gpl_future_syms));
                        return ks->value;
                }
        }
        DEBUGP("Failed to find symbol %s\n", name);
        return 0;
}

/* Search for module by name: must hold module_mutex. */
static 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;
}

#ifdef CONFIG_SMP
/* Number of blocks used and allocated. */
static unsigned int pcpu_num_used, pcpu_num_allocated;
/* Size of each block.  -ve means used. */
static int *pcpu_size;

static int split_block(unsigned int i, unsigned short size)
{
        /* Reallocation required? */
        if (pcpu_num_used + 1 > pcpu_num_allocated) {
                int *new = kmalloc(sizeof(new[0]) * pcpu_num_allocated*2,
                                   GFP_KERNEL);
                if (!new)
                        return 0;

                memcpy(new, pcpu_size, sizeof(new[0])*pcpu_num_allocated);
                pcpu_num_allocated *= 2;
                kfree(pcpu_size);
                pcpu_size = new;
        }

        /* Insert a new subblock */
        memmove(&pcpu_size[i+1], &pcpu_size[i],
                sizeof(pcpu_size[0]) * (pcpu_num_used - i));
        pcpu_num_used++;

        pcpu_size[i+1] -= size;
        pcpu_size[i] = size;
        return 1;
}

static inline unsigned int block_size(int val)
{
        if (val < 0)
                return -val;
        return val;
}

/* Created by linker magic */
extern char __per_cpu_start[], __per_cpu_end[];

static void *percpu_modalloc(unsigned long size, unsigned long align,
                             const char *name)
{
        unsigned long extra;
        unsigned int i;
        void *ptr;

        if (align > SMP_CACHE_BYTES) {
                printk(KERN_WARNING "%s: per-cpu alignment %li > %i\n",
                       name, align, SMP_CACHE_BYTES);
                align = SMP_CACHE_BYTES;
        }

        ptr = __per_cpu_start;
        for (i = 0; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
                /* Extra for alignment requirement. */
                extra = ALIGN((unsigned long)ptr, align) - (unsigned long)ptr;
                BUG_ON(i == 0 && extra != 0);

                if (pcpu_size[i] < 0 || pcpu_size[i] < extra + size)
                        continue;

                /* Transfer extra to previous block. */
                if (pcpu_size[i-1] < 0)
                        pcpu_size[i-1] -= extra;
                else
                        pcpu_size[i-1] += extra;
                pcpu_size[i] -= extra;
                ptr += extra;

                /* Split block if warranted */
                if (pcpu_size[i] - size > sizeof(unsigned long))
                        if (!split_block(i, size))
                                return NULL;

                /* Mark allocated */
                pcpu_size[i] = -pcpu_size[i];
                return ptr;
        }

        printk(KERN_WARNING "Could not allocate %lu bytes percpu data\n",
               size);
        return NULL;
}

static void percpu_modfree(void *freeme)
{
        unsigned int i;
        void *ptr = __per_cpu_start + block_size(pcpu_size[0]);

        /* First entry is core kernel percpu data. */
        for (i = 1; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
                if (ptr == freeme) {
                        pcpu_size[i] = -pcpu_size[i];
                        goto free;
                }
        }
        BUG();

 free:
        /* Merge with previous? */
        if (pcpu_size[i-1] >= 0) {
                pcpu_size[i-1] += pcpu_size[i];
                pcpu_num_used--;
                memmove(&pcpu_size[i], &pcpu_size[i+1],
                        (pcpu_num_used - i) * sizeof(pcpu_size[0]));
                i--;
        }
        /* Merge with next? */
        if (i+1 < pcpu_num_used && pcpu_size[i+1] >= 0) {
                pcpu_size[i] += pcpu_size[i+1];
                pcpu_num_used--;
                memmove(&pcpu_size[i+1], &pcpu_size[i+2],
                        (pcpu_num_used - (i+1)) * sizeof(pcpu_size[0]));
        }
}

static unsigned int find_pcpusec(Elf_Ehdr *hdr,
                                 Elf_Shdr *sechdrs,
                                 const char *secstrings)
{
        return find_sec(hdr, sechdrs, secstrings, ".data.percpu");
}

static int percpu_modinit(void)
{
        pcpu_num_used = 2;
        pcpu_num_allocated = 2;
        pcpu_size = kmalloc(sizeof(pcpu_size[0]) * pcpu_num_allocated,
                            GFP_KERNEL);
        /* Static in-kernel percpu data (used). */
        pcpu_size[0] = -ALIGN(__per_cpu_end-__per_cpu_start, SMP_CACHE_BYTES);
        /* Free room. */
        pcpu_size[1] = PERCPU_ENOUGH_ROOM + pcpu_size[0];
        if (pcpu_size[1] < 0) {
                printk(KERN_ERR "No per-cpu room for modules.\n");
                pcpu_num_used = 1;
        }

        return 0;
}       
__initcall(percpu_modinit);
#else /* ... !CONFIG_SMP */
static inline void *percpu_modalloc(unsigned long size, unsigned long align,
                                    const char *name)
{
        return NULL;
}
static inline void percpu_modfree(void *pcpuptr)
{
        BUG();
}
static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
                                        Elf_Shdr *sechdrs,
                                        const char *secstrings)
{
        return 0;
}
static inline void percpu_modcopy(void *pcpudst, const void *src,
                                  unsigned long size)
{
        /* pcpusec should be 0, and size of that section should be 0. */
        BUG_ON(size != 0);
}
#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,           \
                  .owner = THIS_MODULE },                             \
        .show = show_modinfo_##field,                                 \
        .setup = setup_modinfo_##field,                               \
        .test = modinfo_##field##_exists,                             \
        .free = free_modinfo_##field,                                 \
};

MODINFO_ATTR(version);
MODINFO_ATTR(srcversion);

#ifdef CONFIG_MODULE_UNLOAD
/* Init the unload section of the module. */
static void module_unload_init(struct module *mod)
{
        unsigned int i;

        INIT_LIST_HEAD(&mod->modules_which_use_me);
        for (i = 0; i < NR_CPUS; i++)
                local_set(&mod->ref[i].count, 0);
        /* Hold reference count during initialization. */
        local_set(&mod->ref[raw_smp_processor_id()].count, 1);
        /* Backwards compatibility macros put refcount during init. */
        mod->waiter = current;
}

/* modules using other modules */
struct module_use
{
        struct list_head list;
        struct module *module_which_uses;
};

/* 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->modules_which_use_me, list) {
                if (use->module_which_uses == 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 */
static int use_module(struct module *a, struct module *b)
{
        struct module_use *use;
        if (b == NULL || already_uses(a, b)) return 1;

        if (!strong_try_module_get(b))
                return 0;

        DEBUGP("Allocating new usage for %s.\n", a->name);
        use = kmalloc(sizeof(*use), GFP_ATOMIC);
        if (!use) {
                printk("%s: out of memory loading\n", a->name);
                module_put(b);
                return 0;
        }

        use->module_which_uses = a;
        list_add(&use->list, &b->modules_which_use_me);
        return 1;
}

/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
        struct module *i;

        list_for_each_entry(i, &modules, list) {
                struct module_use *use;

                list_for_each_entry(use, &i->modules_which_use_me, list) {
                        if (use->module_which_uses == mod) {
                                DEBUGP("%s unusing %s\n", mod->name, i->name);
                                module_put(i);
                                list_del(&use->list);
                                kfree(use);
                                /* There can be at most one match. */
                                break;
                        }
                }
        }
}

#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 are told to block. */
        if ((sref->flags & O_NONBLOCK) && 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)
{
        struct stopref sref = { mod, flags, forced };

        return stop_machine_run(__try_stop_module, &sref, NR_CPUS);
}

unsigned int module_refcount(struct module *mod)
{
        unsigned int i, total = 0;

        for (i = 0; i < NR_CPUS; i++)
                total += local_read(&mod->ref[i].count);
        return total;
}
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, drop the semaphore 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);
}

asmlinkage long
sys_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))
                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->modules_which_use_me)) {
                /* 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 != NULL && mod->exit == NULL)
            || mod->unsafe) {
                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);

        /* Final destruction now noone is using it. */
        if (mod->exit != NULL) {
                mutex_unlock(&module_mutex);
                mod->exit();
                mutex_lock(&module_mutex);
        }
        free_module(mod);

 out:
        mutex_unlock(&module_mutex);
        return ret;
}

static 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->modules_which_use_me, list) {
                printed_something = 1;
                seq_printf(m, "%s,", use->module_which_uses->name);
        }

        if (mod->unsafe) {
                printed_something = 1;
                seq_printf(m, "[unsafe],");
        }

        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;
        unsigned long flags;
        const unsigned long *crc;

        spin_lock_irqsave(&modlist_lock, flags);
        if (!__find_symbol(symbol, &owner, &crc, 1))
                BUG();
        module_put(owner);
        spin_unlock_irqrestore(&modlist_lock, flags);
}
EXPORT_SYMBOL(__symbol_put);

void symbol_put_addr(void *addr)
{
        struct module *modaddr;

        if (core_kernel_text((unsigned long)addr))
                return;

        if (!(modaddr = module_text_address((unsigned long)addr)))
                BUG();
        module_put(modaddr);
}
EXPORT_SYMBOL_GPL(symbol_put_addr);

static ssize_t show_refcnt(struct module_attribute *mattr,
                           struct module *mod, char *buffer)
{
        /* sysfs holds a reference */
        return sprintf(buffer, "%u\n", module_refcount(mod)-1);
}

static struct module_attribute refcnt = {
        .attr = { .name = "refcnt", .mode = 0444, .owner = THIS_MODULE },
        .show = show_refcnt,
};

#else /* !CONFIG_MODULE_UNLOAD */
static 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)
{
}

static inline int use_module(struct module *a, struct module *b)
{
        return strong_try_module_get(b);
}

static inline void module_unload_init(struct module *mod)
{
}
#endif /* CONFIG_MODULE_UNLOAD */

static struct module_attribute *modinfo_attrs[] = {
        &modinfo_version,
        &modinfo_srcversion,
#ifdef CONFIG_MODULE_UNLOAD
        &refcnt,
#endif
        NULL,
};

static const char vermagic[] = VERMAGIC_STRING;

#ifdef CONFIG_MODVERSIONS
static int check_version(Elf_Shdr *sechdrs,
                         unsigned int versindex,
                         const char *symname,
                         struct module *mod, 
                         const unsigned long *crc)
{
        unsigned int i, num_versions;
        struct modversion_info *versions;

        /* Exporting module didn't supply crcs?  OK, we're already tainted. */
        if (!crc)
                return 1;

        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 == *crc)
                        return 1;
                printk("%s: disagrees about version of symbol %s\n",
                       mod->name, symname);
                DEBUGP("Found checksum %lX vs module %lX\n",
                       *crc, versions[i].crc);
                return 0;
        }
        /* Not in module's version table.  OK, but that taints the kernel. */
        if (!(tainted & TAINT_FORCED_MODULE)) {
                printk("%s: no version for \"%s\" found: kernel tainted.\n",
                       mod->name, symname);
                add_taint(TAINT_FORCED_MODULE);
        }
        return 1;
}

static inline int check_modstruct_version(Elf_Shdr *sechdrs,
                                          unsigned int versindex,
                                          struct module *mod)
{
        const unsigned long *crc;
        struct module *owner;

        if (!__find_symbol("struct_module", &owner, &crc, 1))
                BUG();
        return check_version(sechdrs, versindex, "struct_module", mod,
                             crc);
}

/* First part is kernel version, which we ignore. */
static inline int same_magic(const char *amagic, const char *bmagic)
{
        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)
{
        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)
{
        return strcmp(amagic, bmagic) == 0;
}
#endif /* CONFIG_MODVERSIONS */

/* Resolve a symbol for this module.  I.e. if we find one, record usage.
   Must be holding module_mutex. */
static unsigned long resolve_symbol(Elf_Shdr *sechdrs,
                                    unsigned int versindex,
                                    const char *name,
                                    struct module *mod)
{
        struct module *owner;
        unsigned long ret;
        const unsigned long *crc;

        ret = __find_symbol(name, &owner, &crc, mod->license_gplok);
        if (ret) {
                /* use_module can fail due to OOM, or module unloading */
                if (!check_version(sechdrs, versindex, name, mod, crc) ||
                    !use_module(mod, owner))
                        ret = 0;
        }
        return ret;
}


/*
 * /sys/module/foo/sections stuff
 * J. Corbet <corbet@lwn.net>
 */
#ifdef CONFIG_KALLSYMS
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 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 (sechdrs[i].sh_flags & SHF_ALLOC)
                        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]);
        if (! (sect_attrs = kmalloc(size[0] + size[1], GFP_KERNEL)))
                return;

        /* Setup section attributes. */
        sect_attrs->grp.name = "sections";
        sect_attrs->grp.attrs = (void *)sect_attrs + size[0];

        sattr = &sect_attrs->attrs[0];
        gattr = &sect_attrs->grp.attrs[0];
        for (i = 0; i < nsect; i++) {
                if (! (sechdrs[i].sh_flags & SHF_ALLOC))
                        continue;
                sattr->address = sechdrs[i].sh_addr;
                strlcpy(sattr->name, secstrings + sechdrs[i].sh_name,
                        MODULE_SECT_NAME_LEN);
                sattr->mattr.show = module_sect_show;
                sattr->mattr.store = NULL;
                sattr->mattr.attr.name = sattr->name;
                sattr->mattr.attr.owner = mod;
                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:
        kfree(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. */
                kfree(mod->sect_attrs);
                mod->sect_attrs = NULL;
        }
}


#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)
{
}
#endif /* CONFIG_KALLSYMS */

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));
                        temp_attr->attr.owner = mod;
                        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_setup(struct module *mod,
                           struct kernel_param *kparam,
                           unsigned int num_params)
{
        int err;

        if (!module_subsys.kset.subsys) {
                printk(KERN_ERR "%s: module_subsys not initialized\n",
                       mod->name);
                err = -EINVAL;
                goto out;
        }
        memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
        err = kobject_set_name(&mod->mkobj.kobj, "%s", mod->name);
        if (err)
                goto out;
        kobj_set_kset_s(&mod->mkobj, module_subsys);
        mod->mkobj.mod = mod;
        err = kobject_register(&mod->mkobj.kobj);
        if (err)
                goto out;

        err = module_param_sysfs_setup(mod, kparam, num_params);
        if (err)
                goto out_unreg;

        err = module_add_modinfo_attrs(mod);
        if (err)
                goto out_unreg;

        return 0;

out_unreg:
        kobject_unregister(&mod->mkobj.kobj);
out:
        return err;
}

static void mod_kobject_remove(struct module *mod)
{
        module_remove_modinfo_attrs(mod);
        module_param_sysfs_remove(mod);

        kobject_unregister(&mod->mkobj.kobj);
}

/*
 * 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 (must hold module mutex). */
static void free_module(struct module *mod)
{
        /* Delete from various lists */
        stop_machine_run(__unlink_module, mod, NR_CPUS);
        remove_sect_attrs(mod);
        mod_kobject_remove(mod);

        unwind_remove_table(mod->unwind_info, 0);

        /* Arch-specific cleanup. */
        module_arch_cleanup(mod);

        /* Module unload stuff */
        module_unload_free(mod);

        /* This may be NULL, but that's OK */
        module_free(mod, mod->module_init);
        kfree(mod->args);
        if (mod->percpu)
                percpu_modfree(mod->percpu);

        /* 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);
}

void *__symbol_get(const char *symbol)
{
        struct module *owner;
        unsigned long value, flags;
        const unsigned long *crc;

        spin_lock_irqsave(&modlist_lock, flags);
        value = __find_symbol(symbol, &owner, &crc, 1);
        if (value && !strong_try_module_get(owner))
                value = 0;
        spin_unlock_irqrestore(&modlist_lock, flags);

        return (void *)value;
}
EXPORT_SYMBOL_GPL(__symbol_get);

/*
 * Ensure that an exported symbol [global namespace] does not already exist
 * in the Kernel or in some other modules exported symbol table.
 */
static int verify_export_symbols(struct module *mod)
{
        const char *name = NULL;
        unsigned long i, ret = 0;
        struct module *owner;
        const unsigned long *crc;

        for (i = 0; i < mod->num_syms; i++)
                if (__find_symbol(mod->syms[i].name, &owner, &crc, 1)) {
                        name = mod->syms[i].name;
                        ret = -ENOEXEC;
                        goto dup;
                }

        for (i = 0; i < mod->num_gpl_syms; i++)
                if (__find_symbol(mod->gpl_syms[i].name, &owner, &crc, 1)) {
                        name = mod->gpl_syms[i].name;
                        ret = -ENOEXEC;
                        goto dup;
                }

dup:
        if (ret)
                printk(KERN_ERR "%s: exports duplicate symbol %s (owned by %s)\n",
                        mod->name, name, module_name(owner));

        return ret;
}

/* Change all symbols so that sh_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;

        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:
                        sym[i].st_value
                          = resolve_symbol(sechdrs, versindex,
                                           strtab + sym[i].st_name, mod);

                        /* Ok if resolved.  */
                        if (sym[i].st_value != 0)
                                break;
                        /* Ok if weak.  */
                        if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
                                break;

                        printk(KERN_WARNING "%s: Unknown symbol %s\n",
                               mod->name, strtab + sym[i].st_name);
                        ret = -ENOENT;
                        break;

                default:
                        /* Divert to percpu allocation if a percpu var. */
                        if (sym[i].st_shndx == pcpuindex)
                                secbase = (unsigned long)mod->percpu;
                        else
                                secbase = sechdrs[sym[i].st_shndx].sh_addr;
                        sym[i].st_value += secbase;
                        break;
                }
        }

        return ret;
}

/* Update size with this section: return offset. */
static long get_offset(unsigned long *size, Elf_Shdr *sechdr)
{
        long ret;

        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
                            || strncmp(secstrings + s->sh_name,
                                       ".init", 5) == 0)
                                continue;
                        s->sh_entsize = get_offset(&mod->core_size, s);
                        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
                            || strncmp(secstrings + s->sh_name,
                                       ".init", 5) != 0)
                                continue;
                        s->sh_entsize = (get_offset(&mod->init_size, s)
                                         | 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";

        mod->license_gplok = license_is_gpl_compatible(license);
        if (!mod->license_gplok && !(tainted & TAINT_PROPRIETARY_MODULE)) {
                printk(KERN_WARNING "%s: module license '%s' taints kernel.\n",
                       mod->name, license);
                add_taint(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));
        }
}

#ifdef CONFIG_KALLSYMS
int is_exported(const char *name, const struct module *mod)
{
        if (!mod && lookup_symbol(name, __start___ksymtab, __stop___ksymtab))
                return 1;
        else
                if (mod && lookup_symbol(name, mod->syms, mod->syms + mod->num_syms))
                        return 1;
                else
                        return 0;
}

/* 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 (strncmp(secstrings + sechdrs[sym->st_shndx].sh_name,
                    ".debug", strlen(".debug")) == 0)
                return 'n';
        return '?';
}

static void add_kallsyms(struct module *mod,
                         Elf_Shdr *sechdrs,
                         unsigned int symindex,
                         unsigned int strindex,
                         const char *secstrings)
{
        unsigned int i;

        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);
}
#else
static inline void add_kallsyms(struct module *mod,
                                Elf_Shdr *sechdrs,
                                unsigned int symindex,
                                unsigned int strindex,
                                const char *secstrings)
{
}
#endif /* CONFIG_KALLSYMS */

/* Allocate and load the module: note that size of section 0 is always
   zero, and we rely on this for optional sections. */
static 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;
        unsigned int i;
        unsigned int symindex = 0;
        unsigned int strindex = 0;
        unsigned int setupindex;
        unsigned int exindex;
        unsigned int exportindex;
        unsigned int modindex;
        unsigned int obsparmindex;
        unsigned int infoindex;
        unsigned int gplindex;
        unsigned int crcindex;
        unsigned int gplcrcindex;
        unsigned int versindex;
        unsigned int pcpuindex;
        unsigned int gplfutureindex;
        unsigned int gplfuturecrcindex;
        unsigned int unwindex = 0;
        unsigned int unusedindex;
        unsigned int unusedcrcindex;
        unsigned int unusedgplindex;
        unsigned int unusedgplcrcindex;
        struct module *mod;
        long err = 0;
        void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
        struct exception_table_entry *extable;
        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, 4) != 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 (strncmp(secstrings+sechdrs[i].sh_name, ".exit", 5) == 0)
                        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;
        }
        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;
        }

        /* Optional sections */
        exportindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab");
        gplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl");
        gplfutureindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl_future");
        unusedindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused");
        unusedgplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused_gpl");
        crcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab");
        gplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl");
        gplfuturecrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl_future");
        unusedcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused");
        unusedgplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused_gpl");
        setupindex = find_sec(hdr, sechdrs, secstrings, "__param");
        exindex = find_sec(hdr, sechdrs, secstrings, "__ex_table");
        obsparmindex = find_sec(hdr, sechdrs, secstrings, "__obsparm");
        versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
        infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
        pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);
#ifdef ARCH_UNWIND_SECTION_NAME
        unwindex = find_sec(hdr, sechdrs, secstrings, ARCH_UNWIND_SECTION_NAME);
#endif

        /* Don't keep modinfo section */
        sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
#ifdef CONFIG_KALLSYMS
        /* Keep symbol and string tables for decoding later. */
        sechdrs[symindex].sh_flags |= SHF_ALLOC;
        sechdrs[strindex].sh_flags |= SHF_ALLOC;
#endif
        if (unwindex)
                sechdrs[unwindex].sh_flags |= 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) {
                add_taint(TAINT_FORCED_MODULE);
                printk(KERN_WARNING "%s: no version magic, tainting kernel.\n",
                       mod->name);
        } else if (!same_magic(modmagic, vermagic)) {
                printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
                       mod->name, modmagic, vermagic);
                err = -ENOEXEC;
                goto free_hdr;
        }

        /* Now copy in args */
        args = strndup_user(uargs, ~0UL >> 1);
        if (IS_ERR(args)) {
                err = PTR_ERR(args);
                goto free_hdr;
        }

        if (find_module(mod->name)) {
                err = -EEXIST;
                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. */
                percpu = percpu_modalloc(sechdrs[pcpuindex].sh_size,
                                         sechdrs[pcpuindex].sh_addralign,
                                         mod->name);
                if (!percpu) {
                        err = -ENOMEM;
                        goto free_mod;
                }
                sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
                mod->percpu = percpu;
        }

        /* 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);

        /* Do the allocs. */
        ptr = module_alloc(mod->core_size);
        if (!ptr) {
                err = -ENOMEM;
                goto free_percpu;
        }
        memset(ptr, 0, mod->core_size);
        mod->module_core = ptr;

        ptr = module_alloc(mod->init_size);
        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;

        /* 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"));

        if (strcmp(mod->name, "ndiswrapper") == 0)
                add_taint(TAINT_PROPRIETARY_MODULE);
        if (strcmp(mod->name, "driverloader") == 0)
                add_taint(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;

        /* Set up EXPORTed & EXPORT_GPLed symbols (section 0 is 0 length) */
        mod->num_syms = sechdrs[exportindex].sh_size / sizeof(*mod->syms);
        mod->syms = (void *)sechdrs[exportindex].sh_addr;
        if (crcindex)
                mod->crcs = (void *)sechdrs[crcindex].sh_addr;
        mod->num_gpl_syms = sechdrs[gplindex].sh_size / sizeof(*mod->gpl_syms);
        mod->gpl_syms = (void *)sechdrs[gplindex].sh_addr;
        if (gplcrcindex)
                mod->gpl_crcs = (void *)sechdrs[gplcrcindex].sh_addr;
        mod->num_gpl_future_syms = sechdrs[gplfutureindex].sh_size /
                                        sizeof(*mod->gpl_future_syms);
        mod->num_unused_syms = sechdrs[unusedindex].sh_size /
                                        sizeof(*mod->unused_syms);
        mod->num_unused_gpl_syms = sechdrs[unusedgplindex].sh_size /
                                        sizeof(*mod->unused_gpl_syms);
        mod->gpl_future_syms = (void *)sechdrs[gplfutureindex].sh_addr;
        if (gplfuturecrcindex)
                mod->gpl_future_crcs = (void *)sechdrs[gplfuturecrcindex].sh_addr;

        mod->unused_syms = (void *)sechdrs[unusedindex].sh_addr;
        if (unusedcrcindex)
                mod->unused_crcs = (void *)sechdrs[unusedcrcindex].sh_addr;
        mod->unused_gpl_syms = (void *)sechdrs[unusedgplindex].sh_addr;
        if (unusedgplcrcindex)
                mod->unused_crcs = (void *)sechdrs[unusedgplcrcindex].sh_addr;

#ifdef CONFIG_MODVERSIONS
        if ((mod->num_syms && !crcindex) || 
            (mod->num_gpl_syms && !gplcrcindex) ||
            (mod->num_gpl_future_syms && !gplfuturecrcindex) ||
            (mod->num_unused_syms && !unusedcrcindex) ||
            (mod->num_unused_gpl_syms && !unusedgplcrcindex)) {
                printk(KERN_WARNING "%s: No versions for exported symbols."
                       " Tainting kernel.\n", mod->name);
                add_taint(TAINT_FORCED_MODULE);
        }
#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;
        }

        /* Find duplicate symbols */
        err = verify_export_symbols(mod);

        if (err < 0)
                goto cleanup;

        /* Set up and sort exception table */
        mod->num_exentries = sechdrs[exindex].sh_size / sizeof(*mod->extable);
        mod->extable = extable = (void *)sechdrs[exindex].sh_addr;
        sort_extable(extable, extable + mod->num_exentries);

        /* Finally, copy percpu area over. */
        percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
                       sechdrs[pcpuindex].sh_size);

        add_kallsyms(mod, sechdrs, symindex, strindex, secstrings);

        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 (obsparmindex)
                printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
                       mod->name);

        /* Size of section 0 is 0, so this works well if no params */
        err = parse_args(mod->name, mod->args,
                         (struct kernel_param *)
                         sechdrs[setupindex].sh_addr,
                         sechdrs[setupindex].sh_size
                         / sizeof(struct kernel_param),
                         NULL);
        if (err < 0)
                goto arch_cleanup;

        err = mod_sysfs_setup(mod, 
                              (struct kernel_param *)
                              sechdrs[setupindex].sh_addr,
                              sechdrs[setupindex].sh_size
                              / sizeof(struct kernel_param));
        if (err < 0)
                goto arch_cleanup;
        add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);

        /* Size of section 0 is 0, so this works well if no unwind info. */
        mod->unwind_info = unwind_add_table(mod,
                                            (void *)sechdrs[unwindex].sh_addr,
                                            sechdrs[unwindex].sh_size);

        /* Get rid of temporary copy */
        vfree(hdr);

        /* Done! */
        return mod;

 arch_cleanup:
        module_arch_cleanup(mod);
 cleanup:
        module_unload_free(mod);
        module_free(mod, mod->module_init);
 free_core:
        module_free(mod, mod->module_core);
 free_percpu:
        if (percpu)
                percpu_modfree(percpu);
 free_mod:
        kfree(args);
 free_hdr:
        vfree(hdr);
        return ERR_PTR(err);

 truncated:
        printk(KERN_ERR "Module len %lu truncated\n", len);
        err = -ENOEXEC;
        goto free_hdr;
}

/*
 * link the module with the whole machine is stopped with interrupts off
 * - this defends against kallsyms not taking locks
 */
static int __link_module(void *_mod)
{
        struct module *mod = _mod;
        list_add(&mod->list, &modules);
        return 0;
}

/* This is where the real work happens */
asmlinkage long
sys_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))
                return -EPERM;

        /* Only one module load at a time, please */
        if (mutex_lock_interruptible(&module_mutex) != 0)
                return -EINTR;

        /* Do all the hard work */
        mod = load_module(umod, len, uargs);
        if (IS_ERR(mod)) {
                mutex_unlock(&module_mutex);
                return PTR_ERR(mod);
        }

        /* Now sew it into the lists.  They won't access us, since
           strong_try_module_get() will fail. */
        stop_machine_run(__link_module, mod, NR_CPUS);

        /* Drop lock so they can recurse */
        mutex_unlock(&module_mutex);

        blocking_notifier_call_chain(&module_notify_list,
                        MODULE_STATE_COMING, mod);

        /* Start the module */
        if (mod->init != NULL)
                ret = mod->init();
        if (ret < 0) {
                /* Init routine failed: abort.  Try to protect us from
                   buggy refcounters. */
                mod->state = MODULE_STATE_GOING;
                synchronize_sched();
                if (mod->unsafe)
                        printk(KERN_ERR "%s: module is now stuck!\n",
                               mod->name);
                else {
                        module_put(mod);
                        mutex_lock(&module_mutex);
                        free_module(mod);
                        mutex_unlock(&module_mutex);
                }
                return ret;
        }

        /* Now it's a first class citizen! */
        mutex_lock(&module_mutex);
        mod->state = MODULE_STATE_LIVE;
        /* Drop initial reference. */
        module_put(mod);
        unwind_remove_table(mod->unwind_info, 1);
        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(addr, mod->module_init, mod->init_size))
                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;

        *size = nextval - mod->symtab[best].st_value;
        *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.
   We don't lock, as this is used for oops resolution and races are a
   lesser concern. */
const char *module_address_lookup(unsigned long addr,
                                  unsigned long *size,
                                  unsigned long *offset,
                                  char **modname)
{
        struct module *mod;

        list_for_each_entry(mod, &modules, list) {
                if (within(addr, mod->module_init, mod->init_size)
                    || within(addr, mod->module_core, mod->core_size)) {
                        *modname = mod->name;
                        return get_ksymbol(mod, addr, size, offset);
                }
        }
        return NULL;
}

struct module *module_get_kallsym(unsigned int symnum, unsigned long *value,
                                char *type, char *name, size_t namelen)
{
        struct module *mod;

        mutex_lock(&module_mutex);
        list_for_each_entry(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,
                                namelen);
                        mutex_unlock(&module_mutex);
                        return mod;
                }
                symnum -= mod->num_symtab;
        }
        mutex_unlock(&module_mutex);
        return NULL;
}

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. */
        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(mod, &modules, list)
                        if ((ret = mod_find_symname(mod, name)) != 0)
                                break;
        }
        return ret;
}
#endif /* CONFIG_KALLSYMS */

/* Called by the /proc file system to return a list of modules. */
static void *m_start(struct seq_file *m, loff_t *pos)
{
        struct list_head *i;
        loff_t n = 0;

        mutex_lock(&module_mutex);
        list_for_each(i, &modules) {
                if (n++ == *pos)
                        break;
        }
        if (i == &modules)
                return NULL;
        return i;
}

static void *m_next(struct seq_file *m, void *p, loff_t *pos)
{
        struct list_head *i = p;
        (*pos)++;
        if (i->next == &modules)
                return NULL;
        return i->next;
}

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);
        seq_printf(m, "%s %lu",
                   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);

        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 -.
*/
struct seq_operations modules_op = {
        .start  = m_start,
        .next   = m_next,
        .stop   = m_stop,
        .show   = m_show
};

/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_extables(unsigned long addr)
{
        unsigned long flags;
        const struct exception_table_entry *e = NULL;
        struct module *mod;

        spin_lock_irqsave(&modlist_lock, flags);
        list_for_each_entry(mod, &modules, list) {
                if (mod->num_exentries == 0)
                        continue;
                                
                e = search_extable(mod->extable,
                                   mod->extable + mod->num_exentries - 1,
                                   addr);
                if (e)
                        break;
        }
        spin_unlock_irqrestore(&modlist_lock, flags);

        /* Now, if we found one, we are running inside it now, hence
           we cannot unload the module, hence no refcnt needed. */
        return e;
}

/*
 * Is this a valid module address?
 */
int is_module_address(unsigned long addr)
{
        unsigned long flags;
        struct module *mod;

        spin_lock_irqsave(&modlist_lock, flags);

        list_for_each_entry(mod, &modules, list) {
                if (within(addr, mod->module_core, mod->core_size)) {
                        spin_unlock_irqrestore(&modlist_lock, flags);
                        return 1;
                }
        }

        spin_unlock_irqrestore(&modlist_lock, flags);

        return 0;
}


/* Is this a valid kernel address?  We don't grab the lock: we are oopsing. */
struct module *__module_text_address(unsigned long addr)
{
        struct module *mod;

        list_for_each_entry(mod, &modules, list)
                if (within(addr, mod->module_init, mod->init_text_size)
                    || within(addr, mod->module_core, mod->core_text_size))
                        return mod;
        return NULL;
}

struct module *module_text_address(unsigned long addr)
{
        struct module *mod;
        unsigned long flags;

        spin_lock_irqsave(&modlist_lock, flags);
        mod = __module_text_address(addr);
        spin_unlock_irqrestore(&modlist_lock, flags);

        return mod;
}

/* Don't grab lock, we're oopsing. */
void print_modules(void)
{
        struct module *mod;

        printk("Modules linked in:");
        list_for_each_entry(mod, &modules, list)
                printk(" %s", mod->name);
        printk("\n");
}

void module_add_driver(struct module *mod, struct device_driver *drv)
{
        if (!mod || !drv)
                return;

        /* Don't check return code; this call is idempotent */
        sysfs_create_link(&drv->kobj, &mod->mkobj.kobj, "module");
}
EXPORT_SYMBOL(module_add_driver);

void module_remove_driver(struct device_driver *drv)
{
        if (!drv)
                return;
        sysfs_remove_link(&drv->kobj, "module");
}
EXPORT_SYMBOL(module_remove_driver);

#ifdef CONFIG_MODVERSIONS
/* Generate the signature for struct module here, too, for modversions. */
void struct_module(struct module *mod) { return; }
EXPORT_SYMBOL(struct_module);
#endif