modules: sysctl to block module loading

[safe/jmp/linux-2.6] / 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/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 <linux/license.h>
#include <asm/sections.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
#include <linux/async.h>
#include <linux/percpu.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))

/* List of modules, protected by module_mutex or preempt_disable
 * (delete uses stop_machine/add uses RCU list operations). */
static DEFINE_MUTEX(module_mutex);
static LIST_HEAD(modules);

/* 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_text_address */
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 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

struct symsearch {
        const struct kernel_symbol *start, *stop;
        const unsigned long *crcs;
        enum {
                NOT_GPL_ONLY,
                GPL_ONLY,
                WILL_BE_GPL_ONLY,
        } licence;
        bool unused;
};

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. */
static 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;
}

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

        /* Output */
        struct module *owner;
        const unsigned long *crc;
        unsigned long value;
};

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->value = syms->start[symnum].value;
        return true;
}

/* Find a symbol, return value, (optional) crc and (optional) module
 * which owns it */
static unsigned long 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.value;
        }

        DEBUGP("Failed to find symbol %s\n", name);
        return -ENOENT;
}

/* 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

#ifdef CONFIG_HAVE_DYNAMIC_PER_CPU_AREA

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

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

        ptr = __alloc_reserved_percpu(size, align);
        if (!ptr)
                printk(KERN_WARNING
                       "Could not allocate %lu bytes percpu data\n", size);
        return ptr;
}

static void percpu_modfree(void *freeme)
{
        free_percpu(freeme);
}

#else /* ... !CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */

/* 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;

                new = krealloc(pcpu_size, sizeof(new[0])*pcpu_num_allocated*2,
                               GFP_KERNEL);
                if (!new)
                        return 0;

                pcpu_num_allocated *= 2;
                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;
}

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

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

        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 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] = -(__per_cpu_end-__per_cpu_start);
        /* 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);

#endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */

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(void *pcpudest, const void *from, unsigned long size)
{
        int cpu;

        for_each_possible_cpu(cpu)
                memcpy(pcpudest + per_cpu_offset(cpu), from, size);
}

#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 },         \
        .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
/* Init the unload section of the module. */
static void module_unload_init(struct module *mod)
{
        int cpu;

        INIT_LIST_HEAD(&mod->modules_which_use_me);
        for_each_possible_cpu(cpu)
                local_set(__module_ref_addr(mod, cpu), 0);
        /* Hold reference count during initialization. */
        local_set(__module_ref_addr(mod, raw_smp_processor_id()), 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;
        int no_warn, err;

        if (b == NULL || already_uses(a, b)) return 1;

        /* If we're interrupted or time out, we fail. */
        if (wait_event_interruptible_timeout(
                    module_wq, (err = strong_try_module_get(b)) != -EBUSY,
                    30 * HZ) <= 0) {
                printk("%s: gave up waiting for init of module %s.\n",
                       a->name, b->name);
                return 0;
        }

        /* If strong_try_module_get() returned a different error, we fail. */
        if (err)
                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);
        no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
        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);
                                sysfs_remove_link(i->holders_dir, mod->name);
                                /* 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'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 total = 0;
        int cpu;

        for_each_possible_cpu(cpu)
                total += local_read(__module_ref_addr(mod, cpu));
        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, 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);
}

/* Block module loading/unloading? */
int modules_disabled = 0;

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';

        /* Create stop_machine threads since free_module relies on
         * a non-failing stop_machine call. */
        ret = stop_machine_create();
        if (ret)
                return ret;

        if (mutex_lock_interruptible(&module_mutex) != 0) {
                ret = -EINTR;
                goto out_stop;
        }

        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 && !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();
        mutex_lock(&module_mutex);
        /* 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);

 out:
        mutex_unlock(&module_mutex);
out_stop:
        stop_machine_destroy();
        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->modules_which_use_me, list) {
                printed_something = 1;
                seq_printf(m, "%s,", use->module_which_uses->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 (IS_ERR_VALUE(find_symbol(symbol, &owner, NULL, true, false)))
                BUG();
        module_put(owner);
        preempt_enable();
}
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)
{
        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) {
                unsigned int cpu = get_cpu();
                local_dec(__module_ref_addr(module, cpu));
                /* Maybe they're waiting for us to drop reference? */
                if (unlikely(!module_is_live(module)))
                        wake_up_process(module->waiter);
                put_cpu();
        }
}
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)
{
}

static inline int use_module(struct module *a, struct module *b)
{
        return strong_try_module_get(b) == 0;
}

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 *symname)
{
#ifdef CONFIG_MODULE_FORCE_LOAD
        if (!test_taint(TAINT_FORCED_MODULE))
                printk("%s: no version for \"%s\" found: kernel tainted.\n",
                       mod->name, symname);
        add_taint_module(mod, TAINT_FORCED_MODULE);
        return 0;
#else
        return -ENOEXEC;
#endif
}

#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;

        /* 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 == *crc)
                        return 1;
                DEBUGP("Found checksum %lX vs module %lX\n",
                       *crc, 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;

        if (IS_ERR_VALUE(find_symbol("struct_module", NULL, &crc, true, false)))
                BUG();
        return check_version(sechdrs, versindex, "struct_module", mod, crc);
}

/* 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)
{
        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.
   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->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
        if (!IS_ERR_VALUE(ret)) {
                /* use_module can fail due to OOM,
                   or module initialization or unloading */
                if (!check_version(sechdrs, versindex, name, mod, crc) ||
                    !use_module(mod, owner))
                        ret = -EINVAL;
        }
        return ret;
}

/*
 * /sys/module/foo/sections stuff
 * J. Corbet <corbet@lwn.net>
 */
#if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS)
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 (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]);
        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 (! (sechdrs[i].sh_flags & SHF_ALLOC))
                        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++;
                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 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;

        /* Count notes sections and allocate structures.  */
        notes = 0;
        for (i = 0; i < nsect; i++)
                if ((sechdrs[i].sh_flags & SHF_ALLOC) &&
                    (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 (!(sechdrs[i].sh_flags & SHF_ALLOC))
                        continue;
                if (sechdrs[i].sh_type == SHT_NOTE) {
                        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
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));
                        error = sysfs_create_file(&mod->mkobj.kobj,&temp_attr->attr);
                        ++temp_attr;
                }
        }
        return error;
}

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);
}

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;
}

int mod_sysfs_setup(struct module *mod,
                           struct kernel_param *kparam,
                           unsigned int num_params)
{
        int err;

        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;

        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);
        return err;
}

static void mod_sysfs_fini(struct module *mod)
{
        kobject_put(&mod->mkobj.kobj);
}

#else /* CONFIG_SYSFS */

static void mod_sysfs_fini(struct module *mod)
{
}

#endif /* CONFIG_SYSFS */

static void mod_kobject_remove(struct module *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 (must hold module_mutex). */
static void free_module(struct module *mod)
{
        /* Delete from various lists */
        stop_machine(__unlink_module, mod, NULL);
        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);

        /* release any pointers to mcount in this module */
        ftrace_release(mod->module_core, mod->core_size);

        /* This may be NULL, but that's OK */
        module_free(mod, mod->module_init);
        kfree(mod->args);
        if (mod->percpu)
                percpu_modfree(mod->percpu);
#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
        if (mod->refptr)
                percpu_modfree(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);
}

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

        preempt_disable();
        value = find_symbol(symbol, &owner, NULL, true, true);
        if (IS_ERR_VALUE(value))
                value = 0;
        else if (strong_try_module_get(owner))
                value = 0;
        preempt_enable();

        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 module's exported symbol table.
 */
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 (!IS_ERR_VALUE(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;

        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 (!IS_ERR_VALUE(sym[i].st_value))
                                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;
}

/* 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
                            || strncmp(secstrings + s->sh_name,
                                       ".init", 5) == 0)
                                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
                            || strncmp(secstrings + s->sh_name,
                                       ".init", 5) != 0)
                                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));
        }
}

#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 (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 */

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) {
                /* 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;
        }
        return ret;
}

/* 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;
        unsigned int num_kp, num_mcount;
        struct kernel_param *kp;
        struct module *mod;
        long err = 0;
        void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
        unsigned long *mseg;
        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);

        /* Create stop_machine threads since the error path relies on
         * a non-failing stop_machine call. */
        err = stop_machine_create();
        if (err)
                goto free_hdr;

        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 (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;
        }
        /* 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;
#ifdef CONFIG_KALLSYMS
        /* Keep symbol and string tables for decoding later. */
        sechdrs[symindex].sh_flags |= SHF_ALLOC;
        sechdrs[strindex].sh_flags |= SHF_ALLOC;
#endif

        /* 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, "magic");
                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;
        }

        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_update_bounds(mod->core_size);
        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);
        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;

#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
        mod->refptr = percpu_modalloc(sizeof(local_t), __alignof__(local_t),
                                      mod->name);
        if (!mod->refptr) {
                err = -ENOMEM;
                goto free_init;
        }
#endif
        /* Now we've moved module, initialize linked lists, etc. */
        module_unload_init(mod);

        /* add kobject, so we can reference it. */
        err = mod_sysfs_init(mod);
        if (err)
                goto free_unload;

        /* 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. */
        kp = section_objs(hdr, sechdrs, secstrings, "__param", sizeof(*kp),
                          &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_MARKERS
        mod->markers = section_objs(hdr, sechdrs, secstrings, "__markers",
                                    sizeof(*mod->markers), &mod->num_markers);
#endif
#ifdef CONFIG_TRACEPOINTS
        mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
                                        "__tracepoints",
                                        sizeof(*mod->tracepoints),
                                        &mod->num_tracepoints);
#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
                ) {
                printk(KERN_WARNING "%s: No versions for exported symbols.\n", mod->name);
                err = try_to_force_load(mod, "nocrc");
                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;
        }

        /* Find duplicate symbols */
        err = verify_export_symbols(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->percpu, (void *)sechdrs[pcpuindex].sh_addr,
                       sechdrs[pcpuindex].sh_size);

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

        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);
        }

        /* sechdrs[0].sh_size is always zero */
        mseg = section_objs(hdr, sechdrs, secstrings, "__mcount_loc",
                            sizeof(*mseg), &num_mcount);
        ftrace_init_module(mod, mseg, mseg + num_mcount);

        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.
         */
        list_add_rcu(&mod->list, &modules);

        err = parse_args(mod->name, mod->args, kp, num_kp, NULL);
        if (err < 0)
                goto unlink;

        err = mod_sysfs_setup(mod, kp, 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);

        stop_machine_destroy();
        /* Done! */
        return mod;

 unlink:
        stop_machine(__unlink_module, mod, NULL);
        module_arch_cleanup(mod);
 cleanup:
        kobject_del(&mod->mkobj.kobj);
        kobject_put(&mod->mkobj.kobj);
        ftrace_release(mod->module_core, mod->core_size);
 free_unload:
        module_unload_free(mod);
 free_init:
#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
        percpu_modfree(mod->refptr);
#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:
        if (percpu)
                percpu_modfree(percpu);
 free_mod:
        kfree(args);
 free_hdr:
        vfree(hdr);
        stop_machine_destroy();
        return ERR_PTR(err);

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

/* 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;

        /* 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);
        }

        /* 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 = 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);
                mutex_lock(&module_mutex);
                free_module(mod);
                mutex_unlock(&module_mutex);
                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"
                       KERN_WARNING "%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);

        mutex_lock(&module_mutex);
        /* Drop initial reference. */
        module_put(mod);
        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;
}
#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 this a valid module address?
 */
int is_module_address(unsigned long addr)
{
        struct module *mod;

        preempt_disable();

        list_for_each_entry_rcu(mod, &modules, list) {
                if (within_module_core(addr, mod)) {
                        preempt_enable();
                        return 1;
                }
        }

        preempt_enable();

        return 0;
}


/* Is this a valid kernel address? */
__notrace_funcgraph struct module *__module_text_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(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;

        preempt_disable();
        mod = __module_text_address(addr);
        preempt_enable();

        return mod;
}

/* Don't grab lock, we're oopsing. */
void print_modules(void)
{
        struct module *mod;
        char buf[8];

        printk("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 struct module here, too, for modversions. */
void struct_module(struct module *mod) { return; }
EXPORT_SYMBOL(struct_module);
#endif

#ifdef CONFIG_MARKERS
void module_update_markers(void)
{
        struct module *mod;

        mutex_lock(&module_mutex);
        list_for_each_entry(mod, &modules, list)
                if (!mod->taints)
                        marker_update_probe_range(mod->markers,
                                mod->markers + mod->num_markers);
        mutex_unlock(&module_mutex);
}
#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