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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/ftrace_event.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <linux/rcupdate.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/vermagic.h>
#include <linux/notifier.h>
#include <linux/sched.h>
#include <linux/stop_machine.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/rculist.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#include <linux/license.h>
#include <asm/sections.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
#include <linux/async.h>
#include <linux/percpu.h>
#include <linux/kmemleak.h>

#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). */
DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);

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

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

static BLOCKING_NOTIFIER_HEAD(module_notify_list);

/* Bounds of module allocation, for speeding __module_address */
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

static bool each_symbol_in_section(const struct symsearch *arr,
                           unsigned int arrsize,
                           struct module *owner,
                           bool (*fn)(const struct symsearch *syms,
                                    struct module *owner,
                                    unsigned int symnum, void *data),
                           void *data)
{
      unsigned int i, j;

      for (j = 0; j < arrsize; j++) {
            for (i = 0; i < arr[j].stop - arr[j].start; i++)
                  if (fn(&arr[j], owner, i, data))
                        return true;
      }

      return false;
}

/* Returns true as soon as fn returns true, otherwise false. */
bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner,
                      unsigned int symnum, void *data), void *data)
{
      struct module *mod;
      const struct symsearch arr[] = {
            { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
              NOT_GPL_ONLY, false },
            { __start___ksymtab_gpl, __stop___ksymtab_gpl,
              __start___kcrctab_gpl,
              GPL_ONLY, false },
            { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
              __start___kcrctab_gpl_future,
              WILL_BE_GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
            { __start___ksymtab_unused, __stop___ksymtab_unused,
              __start___kcrctab_unused,
              NOT_GPL_ONLY, true },
            { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
              __start___kcrctab_unused_gpl,
              GPL_ONLY, true },
#endif
      };

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

      list_for_each_entry_rcu(mod, &modules, list) {
            struct symsearch arr[] = {
                  { mod->syms, mod->syms + mod->num_syms, mod->crcs,
                    NOT_GPL_ONLY, false },
                  { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
                    mod->gpl_crcs,
                    GPL_ONLY, false },
                  { mod->gpl_future_syms,
                    mod->gpl_future_syms + mod->num_gpl_future_syms,
                    mod->gpl_future_crcs,
                    WILL_BE_GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
                  { mod->unused_syms,
                    mod->unused_syms + mod->num_unused_syms,
                    mod->unused_crcs,
                    NOT_GPL_ONLY, true },
                  { mod->unused_gpl_syms,
                    mod->unused_gpl_syms + mod->num_unused_gpl_syms,
                    mod->unused_gpl_crcs,
                    GPL_ONLY, true },
#endif
            };

            if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
                  return true;
      }
      return false;
}
EXPORT_SYMBOL_GPL(each_symbol);

00271 struct find_symbol_arg {
      /* Input */
      const char *name;
      bool gplok;
      bool warn;

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

static bool find_symbol_in_section(const struct symsearch *syms,
                           struct module *owner,
                           unsigned int symnum, void *data)
{
      struct find_symbol_arg *fsa = data;

      if (strcmp(syms->start[symnum].name, fsa->name) != 0)
            return false;

      if (!fsa->gplok) {
            if (syms->licence == GPL_ONLY)
                  return false;
            if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
                  printk(KERN_WARNING "Symbol %s is being used "
                         "by a non-GPL module, which will not "
                         "be allowed in the future\n", fsa->name);
                  printk(KERN_WARNING "Please see the file "
                         "Documentation/feature-removal-schedule.txt "
                         "in the kernel source tree for more details.\n");
            }
      }

#ifdef CONFIG_UNUSED_SYMBOLS
      if (syms->unused && fsa->warn) {
            printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
                   "however this module is using it.\n", fsa->name);
            printk(KERN_WARNING
                   "This symbol will go away in the future.\n");
            printk(KERN_WARNING
                   "Please evalute if this is the right api to use and if "
                   "it really is, submit a report the linux kernel "
                   "mailinglist together with submitting your code for "
                   "inclusion.\n");
      }
#endif

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

/* Find a symbol and return it, along with, (optional) crc and
 * (optional) module which owns it */
const struct kernel_symbol *find_symbol(const char *name,
                              struct module **owner,
                              const unsigned long **crc,
                              bool gplok,
                              bool warn)
{
      struct find_symbol_arg fsa;

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

      if (each_symbol(find_symbol_in_section, &fsa)) {
            if (owner)
                  *owner = fsa.owner;
            if (crc)
                  *crc = fsa.crc;
            return fsa.sym;
      }

      DEBUGP("Failed to find symbol %s\n", name);
      return NULL;
}
EXPORT_SYMBOL_GPL(find_symbol);

/* Search for module by name: must hold module_mutex. */
struct module *find_module(const char *name)
{
      struct module *mod;

      list_for_each_entry(mod, &modules, list) {
            if (strcmp(mod->name, name) == 0)
                  return mod;
      }
      return NULL;
}
EXPORT_SYMBOL_GPL(find_module);

#ifdef CONFIG_SMP

#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;
      int cpu;

      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;

            /* add the per-cpu scanning areas */
            for_each_possible_cpu(cpu)
                  kmemleak_alloc(ptr + per_cpu_offset(cpu), size, 0,
                               GFP_KERNEL);

            /* 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]);
      int cpu;

      /* 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:
      /* remove the per-cpu scanning areas */
      for_each_possible_cpu(cpu)
            kmemleak_free(freeme + per_cpu_offset(cpu));

      /* 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 */
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;
}
EXPORT_SYMBOL_GPL(use_module);

/* 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);
}

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 (!find_symbol(symbol, &owner, NULL, true, false))
            BUG();
      module_put(owner);
      preempt_enable();
}
EXPORT_SYMBOL(__symbol_put);

/* Note this assumes addr is a function, which it currently always is. */
void symbol_put_addr(void *addr)
{
      struct module *modaddr;
      unsigned long a = (unsigned long)dereference_function_descriptor(addr);

      if (core_kernel_text(a))
            return;

      /* module_text_address is safe here: we're supposed to have reference
       * to module from symbol_get, so it can't go away. */
      modaddr = __module_text_address(a);
      BUG_ON(!modaddr);
      module_put(modaddr);
}
EXPORT_SYMBOL_GPL(symbol_put_addr);

static ssize_t show_refcnt(struct module_attribute *mattr,
                     struct module *mod, char *buffer)
{
      return sprintf(buffer, "%u\n", module_refcount(mod));
}

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

void module_put(struct module *module)
{
      if (module) {
            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)
{
}

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

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

static ssize_t show_initstate(struct module_attribute *mattr,
                     struct module *mod, char *buffer)
{
      const char *state = "unknown";

      switch (mod->state) {
      case MODULE_STATE_LIVE:
            state = "live";
            break;
      case MODULE_STATE_COMING:
            state = "coming";
            break;
      case MODULE_STATE_GOING:
            state = "going";
            break;
      }
      return sprintf(buffer, "%s\n", state);
}

static struct module_attribute initstate = {
      .attr = { .name = "initstate", .mode = 0444 },
      .show = show_initstate,
};

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

static const char vermagic[] = VERMAGIC_STRING;

static int try_to_force_load(struct module *mod, const char *reason)
{
#ifdef CONFIG_MODULE_FORCE_LOAD
      if (!test_taint(TAINT_FORCED_MODULE))
            printk(KERN_WARNING "%s: %s: kernel tainted.\n",
                   mod->name, reason);
      add_taint_module(mod, TAINT_FORCED_MODULE);
      return 0;
#else
      return -ENOEXEC;
#endif
}

#ifdef CONFIG_MODVERSIONS
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 (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
                   &crc, true, false))
            BUG();
      return check_version(sechdrs, versindex, "module_layout", 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 const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
                                      unsigned int versindex,
                                      const char *name,
                                      struct module *mod)
{
      struct module *owner;
      const struct kernel_symbol *sym;
      const unsigned long *crc;

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

/*
 * /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;

      /* failed to create section attributes, so can't create notes */
      if (!mod->sect_attrs)
            return;

      /* Count notes sections and allocate structures.  */
      notes = 0;
      for (i = 0; i < nsect; i++)
            if ((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);

      /* Free any allocated parameters. */
      destroy_params(mod->kp, mod->num_kp);

      /* This may be NULL, but that's OK */
      module_free(mod, mod->module_init);
      kfree(mod->args);
      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;
      const struct kernel_symbol *sym;

      preempt_disable();
      sym = find_symbol(symbol, &owner, NULL, true, true);
      if (sym && strong_try_module_get(owner))
            sym = NULL;
      preempt_enable();

      return sym ? (void *)sym->value : NULL;
}
EXPORT_SYMBOL_GPL(__symbol_get);

/*
 * Ensure that an exported symbol [global namespace] does not already exist
 * in the kernel or in some other module's exported symbol table.
 */
static int verify_export_symbols(struct module *mod)
{
      unsigned int i;
      struct module *owner;
      const struct kernel_symbol *s;
      struct {
            const struct kernel_symbol *sym;
            unsigned int num;
      } arr[] = {
            { mod->syms, mod->num_syms },
            { mod->gpl_syms, mod->num_gpl_syms },
            { mod->gpl_future_syms, mod->num_gpl_future_syms },
#ifdef CONFIG_UNUSED_SYMBOLS
            { mod->unused_syms, mod->num_unused_syms },
            { mod->unused_gpl_syms, mod->num_unused_gpl_syms },
#endif
      };

      for (i = 0; i < ARRAY_SIZE(arr); i++) {
            for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
                  if (find_symbol(s->name, &owner, NULL, true, false)) {
                        printk(KERN_ERR
                               "%s: exports duplicate symbol %s"
                               " (owned by %s)\n",
                               mod->name, s->name, module_name(owner));
                        return -ENOEXEC;
                  }
            }
      }
      return 0;
}

/* Change all symbols so that st_value encodes the pointer directly. */
static int simplify_symbols(Elf_Shdr *sechdrs,
                      unsigned int symindex,
                      const char *strtab,
                      unsigned int versindex,
                      unsigned int pcpuindex,
                      struct module *mod)
{
      Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
      unsigned long secbase;
      unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
      int ret = 0;
      const struct kernel_symbol *ksym;

      for (i = 1; i < n; i++) {
            switch (sym[i].st_shndx) {
            case SHN_COMMON:
                  /* We compiled with -fno-common.  These are not
                     supposed to happen.  */
                  DEBUGP("Common symbol: %s\n", strtab + sym[i].st_name);
                  printk("%s: please compile with -fno-common\n",
                         mod->name);
                  ret = -ENOEXEC;
                  break;

            case SHN_ABS:
                  /* Don't need to do anything */
                  DEBUGP("Absolute symbol: 0x%08lx\n",
                         (long)sym[i].st_value);
                  break;

            case SHN_UNDEF:
                  ksym = resolve_symbol(sechdrs, versindex,
                                    strtab + sym[i].st_name, mod);
                  /* Ok if resolved.  */
                  if (ksym) {
                        sym[i].st_value = ksym->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
                      || strstarts(secstrings + s->sh_name, ".init"))
                        continue;
                  s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
                  DEBUGP("\t%s\n", secstrings + s->sh_name);
            }
            if (m == 0)
                  mod->core_text_size = mod->core_size;
      }

      DEBUGP("Init section allocation order:\n");
      for (m = 0; m < ARRAY_SIZE(masks); ++m) {
            for (i = 0; i < hdr->e_shnum; ++i) {
                  Elf_Shdr *s = &sechdrs[i];

                  if ((s->sh_flags & masks[m][0]) != masks[m][0]
                      || (s->sh_flags & masks[m][1])
                      || s->sh_entsize != ~0UL
                      || !strstarts(secstrings + s->sh_name, ".init"))
                        continue;
                  s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
                               | INIT_OFFSET_MASK);
                  DEBUGP("\t%s\n", secstrings + s->sh_name);
            }
            if (m == 0)
                  mod->init_text_size = mod->init_size;
      }
}

static void set_license(struct module *mod, const char *license)
{
      if (!license)
            license = "unspecified";

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

/* Parse tag=value strings from .modinfo section */
static char *next_string(char *string, unsigned long *secsize)
{
      /* Skip non-zero chars */
      while (string[0]) {
            string++;
            if ((*secsize)-- <= 1)
                  return NULL;
      }

      /* Skip any zero padding. */
      while (!string[0]) {
            string++;
            if ((*secsize)-- <= 1)
                  return NULL;
      }
      return string;
}

static char *get_modinfo(Elf_Shdr *sechdrs,
                   unsigned int info,
                   const char *tag)
{
      char *p;
      unsigned int taglen = strlen(tag);
      unsigned long size = sechdrs[info].sh_size;

      for (p = (char *)sechdrs[info].sh_addr; p; p = next_string(p, &size)) {
            if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
                  return p + taglen + 1;
      }
      return NULL;
}

static void setup_modinfo(struct module *mod, Elf_Shdr *sechdrs,
                    unsigned int infoindex)
{
      struct module_attribute *attr;
      int i;

      for (i = 0; (attr = modinfo_attrs[i]); i++) {
            if (attr->setup)
                  attr->setup(mod,
                            get_modinfo(sechdrs,
                                    infoindex,
                                    attr->attr.name));
      }
}

#ifdef CONFIG_KALLSYMS

/* lookup symbol in given range of kernel_symbols */
static const struct kernel_symbol *lookup_symbol(const char *name,
      const struct kernel_symbol *start,
      const struct kernel_symbol *stop)
{
      const struct kernel_symbol *ks = start;
      for (; ks < stop; ks++)
            if (strcmp(ks->name, name) == 0)
                  return ks;
      return NULL;
}

static int is_exported(const char *name, unsigned long value,
                   const struct module *mod)
{
      const struct kernel_symbol *ks;
      if (!mod)
            ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
      else
            ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
      return ks != NULL && ks->value == value;
}

/* As per nm */
static char elf_type(const Elf_Sym *sym,
                 Elf_Shdr *sechdrs,
                 const char *secstrings,
                 struct module *mod)
{
      if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
            if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
                  return 'v';
            else
                  return 'w';
      }
      if (sym->st_shndx == SHN_UNDEF)
            return 'U';
      if (sym->st_shndx == SHN_ABS)
            return 'a';
      if (sym->st_shndx >= SHN_LORESERVE)
            return '?';
      if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
            return 't';
      if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
          && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
            if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
                  return 'r';
            else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
                  return 'g';
            else
                  return 'd';
      }
      if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
            if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
                  return 's';
            else
                  return 'b';
      }
      if (strstarts(secstrings + sechdrs[sym->st_shndx].sh_name, ".debug"))
            return 'n';
      return '?';
}

static 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;
}

#ifdef CONFIG_DEBUG_KMEMLEAK
static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
                         Elf_Shdr *sechdrs, char *secstrings)
{
      unsigned int i;

      /* only scan the sections containing data */
      kmemleak_scan_area(mod->module_core, (unsigned long)mod -
                     (unsigned long)mod->module_core,
                     sizeof(struct module), GFP_KERNEL);

      for (i = 1; i < hdr->e_shnum; i++) {
            if (!(sechdrs[i].sh_flags & SHF_ALLOC))
                  continue;
            if (strncmp(secstrings + sechdrs[i].sh_name, ".data", 5) != 0
                && strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) != 0)
                  continue;

            kmemleak_scan_area(mod->module_core, sechdrs[i].sh_addr -
                           (unsigned long)mod->module_core,
                           sechdrs[i].sh_size, GFP_KERNEL);
      }
}
#else
static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
                              Elf_Shdr *sechdrs, char *secstrings)
{
}
#endif

/* Allocate and load the module: note that size of section 0 is always
   zero, and we rely on this for optional sections. */
static noinline struct module *load_module(void __user *umod,
                          unsigned long len,
                          const char __user *uargs)
{
      Elf_Ehdr *hdr;
      Elf_Shdr *sechdrs;
      char *secstrings, *args, *modmagic, *strtab = NULL;
      char *staging;
      unsigned int i;
      unsigned int symindex = 0;
      unsigned int strindex = 0;
      unsigned int modindex, versindex, infoindex, pcpuindex;
      struct module *mod;
      long err = 0;
      void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
      mm_segment_t old_fs;

      DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
             umod, len, uargs);
      if (len < sizeof(*hdr))
            return ERR_PTR(-ENOEXEC);

      /* Suck in entire file: we'll want most of it. */
      /* vmalloc barfs on "unusual" numbers.  Check here */
      if (len > 64 * 1024 * 1024 || (hdr = vmalloc(len)) == NULL)
            return ERR_PTR(-ENOMEM);

      if (copy_from_user(hdr, umod, len) != 0) {
            err = -EFAULT;
            goto free_hdr;
      }

      /* Sanity checks against insmoding binaries or wrong arch,
           weird elf version */
      if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
          || hdr->e_type != ET_REL
          || !elf_check_arch(hdr)
          || hdr->e_shentsize != sizeof(*sechdrs)) {
            err = -ENOEXEC;
            goto free_hdr;
      }

      if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr))
            goto truncated;

      /* Convenience variables */
      sechdrs = (void *)hdr + hdr->e_shoff;
      secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
      sechdrs[0].sh_addr = 0;

      for (i = 1; i < hdr->e_shnum; i++) {
            if (sechdrs[i].sh_type != SHT_NOBITS
                && len < sechdrs[i].sh_offset + sechdrs[i].sh_size)
                  goto truncated;

            /* Mark all sections sh_addr with their address in the
               temporary image. */
            sechdrs[i].sh_addr = (size_t)hdr + sechdrs[i].sh_offset;

            /* Internal symbols and strings. */
            if (sechdrs[i].sh_type == SHT_SYMTAB) {
                  symindex = i;
                  strindex = sechdrs[i].sh_link;
                  strtab = (char *)hdr + sechdrs[strindex].sh_offset;
            }
#ifndef CONFIG_MODULE_UNLOAD
            /* Don't load .exit sections */
            if (strstarts(secstrings+sechdrs[i].sh_name, ".exit"))
                  sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
#endif
      }

      modindex = find_sec(hdr, sechdrs, secstrings,
                      ".gnu.linkonce.this_module");
      if (!modindex) {
            printk(KERN_WARNING "No module found in object\n");
            err = -ENOEXEC;
            goto free_hdr;
      }
      /* This is temporary: point mod into copy of data. */
      mod = (void *)sechdrs[modindex].sh_addr;

      if (symindex == 0) {
            printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
                   mod->name);
            err = -ENOEXEC;
            goto free_hdr;
      }

      versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
      infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
      pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);

      /* Don't keep modinfo and version sections. */
      sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
      sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
#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, "bad vermagic");
            if (err)
                  goto free_hdr;
      } else if (!same_magic(modmagic, vermagic, versindex)) {
            printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
                   mod->name, modmagic, vermagic);
            err = -ENOEXEC;
            goto free_hdr;
      }

      staging = get_modinfo(sechdrs, infoindex, "staging");
      if (staging) {
            add_taint_module(mod, TAINT_CRAP);
            printk(KERN_WARNING "%s: module is from the staging directory,"
                   " the quality is unknown, you have been warned.\n",
                   mod->name);
      }

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

      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);
      /*
       * The pointer to this block is stored in the module structure
       * which is inside the block. Just mark it as not being a
       * leak.
       */
      kmemleak_not_leak(ptr);
      if (!ptr) {
            err = -ENOMEM;
            goto free_percpu;
      }
      memset(ptr, 0, mod->core_size);
      mod->module_core = ptr;

      ptr = module_alloc_update_bounds(mod->init_size);
      /*
       * The pointer to this block is stored in the module structure
       * which is inside the block. This block doesn't need to be
       * scanned as it contains data and code that will be freed
       * after the module is initialized.
       */
      kmemleak_ignore(ptr);
      if (!ptr && mod->init_size) {
            err = -ENOMEM;
            goto free_core;
      }
      memset(ptr, 0, mod->init_size);
      mod->module_init = ptr;

      /* Transfer each section which specifies SHF_ALLOC */
      DEBUGP("final section addresses:\n");
      for (i = 0; i < hdr->e_shnum; i++) {
            void *dest;

            if (!(sechdrs[i].sh_flags & SHF_ALLOC))
                  continue;

            if (sechdrs[i].sh_entsize & INIT_OFFSET_MASK)
                  dest = mod->module_init
                        + (sechdrs[i].sh_entsize & ~INIT_OFFSET_MASK);
            else
                  dest = mod->module_core + sechdrs[i].sh_entsize;

            if (sechdrs[i].sh_type != SHT_NOBITS)
                  memcpy(dest, (void *)sechdrs[i].sh_addr,
                         sechdrs[i].sh_size);
            /* Update sh_addr to point to copy in image. */
            sechdrs[i].sh_addr = (unsigned long)dest;
            DEBUGP("\t0x%lx %s\n", sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name);
      }
      /* Module has been moved. */
      mod = (void *)sechdrs[modindex].sh_addr;
      kmemleak_load_module(mod, hdr, sechdrs, secstrings);

#if defined(CONFIG_MODULE_UNLOAD) && 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. */
      mod->kp = section_objs(hdr, sechdrs, secstrings, "__param",
                         sizeof(*mod->kp), &mod->num_kp);
      mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",
                         sizeof(*mod->syms), &mod->num_syms);
      mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");
      mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",
                             sizeof(*mod->gpl_syms),
                             &mod->num_gpl_syms);
      mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");
      mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,
                                  "__ksymtab_gpl_future",
                                  sizeof(*mod->gpl_future_syms),
                                  &mod->num_gpl_future_syms);
      mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,
                                  "__kcrctab_gpl_future");

#ifdef CONFIG_UNUSED_SYMBOLS
      mod->unused_syms = section_objs(hdr, sechdrs, secstrings,
                              "__ksymtab_unused",
                              sizeof(*mod->unused_syms),
                              &mod->num_unused_syms);
      mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,
                              "__kcrctab_unused");
      mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,
                                  "__ksymtab_unused_gpl",
                                  sizeof(*mod->unused_gpl_syms),
                                  &mod->num_unused_gpl_syms);
      mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,
                                  "__kcrctab_unused_gpl");
#endif
#ifdef CONFIG_CONSTRUCTORS
      mod->ctors = section_objs(hdr, sechdrs, secstrings, ".ctors",
                          sizeof(*mod->ctors), &mod->num_ctors);
#endif

#ifdef CONFIG_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_EVENT_TRACING
      mod->trace_events = section_objs(hdr, sechdrs, secstrings,
                               "_ftrace_events",
                               sizeof(*mod->trace_events),
                               &mod->num_trace_events);
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
      /* sechdrs[0].sh_size is always zero */
      mod->ftrace_callsites = section_objs(hdr, sechdrs, secstrings,
                                   "__mcount_loc",
                                   sizeof(*mod->ftrace_callsites),
                                   &mod->num_ftrace_callsites);
#endif
#ifdef CONFIG_MODVERSIONS
      if ((mod->num_syms && !mod->crcs)
          || (mod->num_gpl_syms && !mod->gpl_crcs)
          || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
#ifdef CONFIG_UNUSED_SYMBOLS
          || (mod->num_unused_syms && !mod->unused_crcs)
          || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
#endif
            ) {
            err = try_to_force_load(mod,
                              "no versions for exported symbols");
            if (err)
                  goto cleanup;
      }
#endif

      /* Now do relocations. */
      for (i = 1; i < hdr->e_shnum; i++) {
            const char *strtab = (char *)sechdrs[strindex].sh_addr;
            unsigned int info = sechdrs[i].sh_info;

            /* Not a valid relocation section? */
            if (info >= hdr->e_shnum)
                  continue;

            /* Don't bother with non-allocated sections */
            if (!(sechdrs[info].sh_flags & SHF_ALLOC))
                  continue;

            if (sechdrs[i].sh_type == SHT_REL)
                  err = apply_relocate(sechdrs, strtab, symindex, i,mod);
            else if (sechdrs[i].sh_type == SHT_RELA)
                  err = apply_relocate_add(sechdrs, strtab, symindex, i,
                                     mod);
            if (err < 0)
                  goto cleanup;
      }

        /* 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);
      }

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

      err = mod_sysfs_setup(mod, mod->kp, mod->num_kp);
      if (err < 0)
            goto unlink;
      add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
      add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);

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

      /* Done! */
      return mod;

 unlink:
      /* Unlink carefully: kallsyms could be walking list. */
      list_del_rcu(&mod->list);
      synchronize_sched();
      module_arch_cleanup(mod);
 cleanup:
      kobject_del(&mod->mkobj.kobj);
      kobject_put(&mod->mkobj.kobj);
 free_unload:
      module_unload_free(mod);
#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
 free_init:
      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);
      return ERR_PTR(err);

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

/* Call module constructors. */
static void do_mod_ctors(struct module *mod)
{
#ifdef CONFIG_CONSTRUCTORS
      unsigned long i;

      for (i = 0; i < mod->num_ctors; i++)
            mod->ctors[i]();
#endif
}

/* This is where the real work happens */
SYSCALL_DEFINE3(init_module, void __user *, umod,
            unsigned long, len, const char __user *, uargs)
{
      struct module *mod;
      int ret = 0;

      /* Must have permission */
      if (!capable(CAP_SYS_MODULE) || modules_disabled)
            return -EPERM;

      /* 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);

      do_mod_ctors(mod);
      /* Start the module */
      if (mod->init != NULL)
            ret = do_one_initcall(mod->init);
      if (ret < 0) {
            /* Init routine failed: abort.  Try to protect us from
                   buggy refcounters. */
            mod->state = MODULE_STATE_GOING;
            synchronize_sched();
            module_put(mod);
            blocking_notifier_call_chain(&module_notify_list,
                                   MODULE_STATE_GOING, mod);
            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"
"%s: loading module anyway...\n",
                   __func__, mod->name, ret,
                   __func__);
            dump_stack();
      }

      /* Now it's a first class citizen!  Wake up anyone waiting for it. */
      mod->state = MODULE_STATE_LIVE;
      wake_up(&module_wq);
      blocking_notifier_call_chain(&module_notify_list,
                             MODULE_STATE_LIVE, mod);

      /* We need to finish all async code before the module init sequence is done */
      async_synchronize_full();

      mutex_lock(&module_mutex);
      /* Drop initial reference. */
      module_put(mod);
      trim_init_extable(mod);
      module_free(mod, mod->module_init);
      mod->module_init = NULL;
      mod->init_size = 0;
      mod->init_text_size = 0;
      mutex_unlock(&module_mutex);

      return 0;
}

static inline int within(unsigned long addr, void *start, unsigned long size)
{
      return ((void *)addr >= start && (void *)addr < start + size);
}

#ifdef CONFIG_KALLSYMS
/*
 * This ignores the intensely annoying "mapping symbols" found
 * in ARM ELF files: $a, $t and $d.
 */
static inline int is_arm_mapping_symbol(const char *str)
{
      return str[0] == '$' && strchr("atd", str[1])
             && (str[2] == '\0' || str[2] == '.');
}

static const char *get_ksymbol(struct module *mod,
                         unsigned long addr,
                         unsigned long *size,
                         unsigned long *offset)
{
      unsigned int i, best = 0;
      unsigned long nextval;

      /* At worse, next value is at end of module */
      if (within_module_init(addr, mod))
            nextval = (unsigned long)mod->module_init+mod->init_text_size;
      else
            nextval = (unsigned long)mod->module_core+mod->core_text_size;

      /* Scan for closest preceeding symbol, and next symbol. (ELF
         starts real symbols at 1). */
      for (i = 1; i < mod->num_symtab; i++) {
            if (mod->symtab[i].st_shndx == SHN_UNDEF)
                  continue;

            /* We ignore unnamed symbols: they're uninformative
             * and inserted at a whim. */
            if (mod->symtab[i].st_value <= addr
                && mod->symtab[i].st_value > mod->symtab[best].st_value
                && *(mod->strtab + mod->symtab[i].st_name) != '\0'
                && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
                  best = i;
            if (mod->symtab[i].st_value > addr
                && mod->symtab[i].st_value < nextval
                && *(mod->strtab + mod->symtab[i].st_name) != '\0'
                && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
                  nextval = mod->symtab[i].st_value;
      }

      if (!best)
            return NULL;

      if (size)
            *size = nextval - mod->symtab[best].st_value;
      if (offset)
            *offset = addr - mod->symtab[best].st_value;
      return mod->strtab + mod->symtab[best].st_name;
}

/* For kallsyms to ask for address resolution.  NULL means not found.  Careful
 * not to lock to avoid deadlock on oopses, simply disable preemption. */
const char *module_address_lookup(unsigned long addr,
                      unsigned long *size,
                      unsigned long *offset,
                      char **modname,
                      char *namebuf)
{
      struct module *mod;
      const char *ret = NULL;

      preempt_disable();
      list_for_each_entry_rcu(mod, &modules, list) {
            if (within_module_init(addr, mod) ||
                within_module_core(addr, mod)) {
                  if (modname)
                        *modname = mod->name;
                  ret = get_ksymbol(mod, addr, size, offset);
                  break;
            }
      }
      /* Make a copy in here where it's safe */
      if (ret) {
            strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
            ret = namebuf;
      }
      preempt_enable();
      return ret;
}

int lookup_module_symbol_name(unsigned long addr, char *symname)
{
      struct module *mod;

      preempt_disable();
      list_for_each_entry_rcu(mod, &modules, list) {
            if (within_module_init(addr, mod) ||
                within_module_core(addr, mod)) {
                  const char *sym;

                  sym = get_ksymbol(mod, addr, NULL, NULL);
                  if (!sym)
                        goto out;
                  strlcpy(symname, sym, KSYM_NAME_LEN);
                  preempt_enable();
                  return 0;
            }
      }
out:
      preempt_enable();
      return -ERANGE;
}

int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
                  unsigned long *offset, char *modname, char *name)
{
      struct module *mod;

      preempt_disable();
      list_for_each_entry_rcu(mod, &modules, list) {
            if (within_module_init(addr, mod) ||
                within_module_core(addr, mod)) {
                  const char *sym;

                  sym = get_ksymbol(mod, addr, size, offset);
                  if (!sym)
                        goto out;
                  if (modname)
                        strlcpy(modname, mod->name, MODULE_NAME_LEN);
                  if (name)
                        strlcpy(name, sym, KSYM_NAME_LEN);
                  preempt_enable();
                  return 0;
            }
      }
out:
      preempt_enable();
      return -ERANGE;
}

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

      preempt_disable();
      list_for_each_entry_rcu(mod, &modules, list) {
            if (symnum < mod->num_symtab) {
                  *value = mod->symtab[symnum].st_value;
                  *type = mod->symtab[symnum].st_info;
                  strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
                        KSYM_NAME_LEN);
                  strlcpy(module_name, mod->name, MODULE_NAME_LEN);
                  *exported = is_exported(name, *value, mod);
                  preempt_enable();
                  return 0;
            }
            symnum -= mod->num_symtab;
      }
      preempt_enable();
      return -ERANGE;
}

static unsigned long mod_find_symname(struct module *mod, const char *name)
{
      unsigned int i;

      for (i = 0; i < mod->num_symtab; i++)
            if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
                mod->symtab[i].st_info != 'U')
                  return mod->symtab[i].st_value;
      return 0;
}

/* Look for this name: can be of form module:name. */
unsigned long module_kallsyms_lookup_name(const char *name)
{
      struct module *mod;
      char *colon;
      unsigned long ret = 0;

      /* Don't lock: we're in enough trouble already. */
      preempt_disable();
      if ((colon = strchr(name, ':')) != NULL) {
            *colon = '\0';
            if ((mod = find_module(name)) != NULL)
                  ret = mod_find_symname(mod, colon+1);
            *colon = ':';
      } else {
            list_for_each_entry_rcu(mod, &modules, list)
                  if ((ret = mod_find_symname(mod, name)) != 0)
                        break;
      }
      preempt_enable();
      return ret;
}

int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
                                   struct module *, unsigned long),
                           void *data)
{
      struct module *mod;
      unsigned int i;
      int ret;

      list_for_each_entry(mod, &modules, list) {
            for (i = 0; i < mod->num_symtab; i++) {
                  ret = fn(data, mod->strtab + mod->symtab[i].st_name,
                         mod, mod->symtab[i].st_value);
                  if (ret != 0)
                        return ret;
            }
      }
      return 0;
}
#endif /* CONFIG_KALLSYMS */

static char *module_flags(struct module *mod, char *buf)
{
      int bx = 0;

      if (mod->taints ||
          mod->state == MODULE_STATE_GOING ||
          mod->state == MODULE_STATE_COMING) {
            buf[bx++] = '(';
            if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
                  buf[bx++] = 'P';
            if (mod->taints & (1 << TAINT_FORCED_MODULE))
                  buf[bx++] = 'F';
            if (mod->taints & (1 << TAINT_CRAP))
                  buf[bx++] = 'C';
            /*
             * TAINT_FORCED_RMMOD: could be added.
             * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
             * apply to modules.
             */

            /* Show a - for module-is-being-unloaded */
            if (mod->state == MODULE_STATE_GOING)
                  buf[bx++] = '-';
            /* Show a + for module-is-being-loaded */
            if (mod->state == MODULE_STATE_COMING)
                  buf[bx++] = '+';
            buf[bx++] = ')';
      }
      buf[bx] = '\0';

      return buf;
}

#ifdef CONFIG_PROC_FS
/* Called by the /proc file system to return a list of modules. */
static void *m_start(struct seq_file *m, loff_t *pos)
{
      mutex_lock(&module_mutex);
      return seq_list_start(&modules, *pos);
}

static void *m_next(struct seq_file *m, void *p, loff_t *pos)
{
      return seq_list_next(p, &modules, pos);
}

static void m_stop(struct seq_file *m, void *p)
{
      mutex_unlock(&module_mutex);
}

static int m_show(struct seq_file *m, void *p)
{
      struct module *mod = list_entry(p, struct module, list);
      char buf[8];

      seq_printf(m, "%s %u",
               mod->name, mod->init_size + mod->core_size);
      print_unload_info(m, mod);

      /* Informative for users. */
      seq_printf(m, " %s",
               mod->state == MODULE_STATE_GOING ? "Unloading":
               mod->state == MODULE_STATE_COMING ? "Loading":
               "Live");
      /* Used by oprofile and other similar tools. */
      seq_printf(m, " 0x%p", mod->module_core);

      /* Taints info */
      if (mod->taints)
            seq_printf(m, " %s", module_flags(mod, buf));

      seq_printf(m, "\n");
      return 0;
}

/* Format: modulename size refcount deps address

   Where refcount is a number or -, and deps is a comma-separated list
   of depends or -.
*/
static const struct seq_operations modules_op = {
      .start      = m_start,
      .next = m_next,
      .stop = m_stop,
      .show = m_show
};

static int modules_open(struct inode *inode, struct file *file)
{
      return seq_open(file, &modules_op);
}

static const struct file_operations proc_modules_operations = {
      .open       = modules_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = seq_release,
};

static int __init proc_modules_init(void)
{
      proc_create("modules", 0, NULL, &proc_modules_operations);
      return 0;
}
module_init(proc_modules_init);
#endif

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

      preempt_disable();
      list_for_each_entry_rcu(mod, &modules, list) {
            if (mod->num_exentries == 0)
                  continue;

            e = search_extable(mod->extable,
                           mod->extable + mod->num_exentries - 1,
                           addr);
            if (e)
                  break;
      }
      preempt_enable();

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

/*
 * is_module_address - is this address inside a module?
 * @addr: the address to check.
 *
 * See is_module_text_address() if you simply want to see if the address
 * is code (not data).
 */
bool is_module_address(unsigned long addr)
{
      bool ret;

      preempt_disable();
      ret = __module_address(addr) != NULL;
      preempt_enable();

      return ret;
}

/*
 * __module_address - get the module which contains an address.
 * @addr: the address.
 *
 * Must be called with preempt disabled or module mutex held so that
 * module doesn't get freed during this.
 */
struct module *__module_address(unsigned long addr)
{
      struct module *mod;

      if (addr < module_addr_min || addr > module_addr_max)
            return NULL;

      list_for_each_entry_rcu(mod, &modules, list)
            if (within_module_core(addr, mod)
                || within_module_init(addr, mod))
                  return mod;
      return NULL;
}
EXPORT_SYMBOL_GPL(__module_address);

/*
 * is_module_text_address - is this address inside module code?
 * @addr: the address to check.
 *
 * See is_module_address() if you simply want to see if the address is
 * anywhere in a module.  See kernel_text_address() for testing if an
 * address corresponds to kernel or module code.
 */
bool is_module_text_address(unsigned long addr)
{
      bool ret;

      preempt_disable();
      ret = __module_text_address(addr) != NULL;
      preempt_enable();

      return ret;
}

/*
 * __module_text_address - get the module whose code contains an address.
 * @addr: the address.
 *
 * Must be called with preempt disabled or module mutex held so that
 * module doesn't get freed during this.
 */
struct module *__module_text_address(unsigned long addr)
{
      struct module *mod = __module_address(addr);
      if (mod) {
            /* Make sure it's within the text section. */
            if (!within(addr, mod->module_init, mod->init_text_size)
                && !within(addr, mod->module_core, mod->core_text_size))
                  mod = NULL;
      }
      return mod;
}
EXPORT_SYMBOL_GPL(__module_text_address);

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

      printk(KERN_DEFAULT "Modules linked in:");
      /* Most callers should already have preempt disabled, but make sure */
      preempt_disable();
      list_for_each_entry_rcu(mod, &modules, list)
            printk(" %s%s", mod->name, module_flags(mod, buf));
      preempt_enable();
      if (last_unloaded_module[0])
            printk(" [last unloaded: %s]", last_unloaded_module);
      printk("\n");
}

#ifdef CONFIG_MODVERSIONS
/* Generate the signature for all relevant module structures here.
 * If these change, we don't want to try to parse the module. */
void module_layout(struct module *mod,
               struct modversion_info *ver,
               struct kernel_param *kp,
               struct kernel_symbol *ks,
               struct marker *marker,
               struct tracepoint *tp)
{
}
EXPORT_SYMBOL(module_layout);
#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

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