LXR linux/mm/init-mm.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/mm_types.h>
   3#include <linux/rbtree.h>
   4#include <linux/rwsem.h>
   5#include <linux/spinlock.h>
   6#include <linux/list.h>
   7#include <linux/cpumask.h>
   8
   9#include <linux/atomic.h>
  10#include <linux/user_namespace.h>
  11#include <asm/pgtable.h>
  12#include <asm/mmu.h>
  13
  14#ifndef INIT_MM_CONTEXT
  15#define INIT_MM_CONTEXT(name)
  16#endif
  17
  18/*
  19 * For dynamically allocated mm_structs, there is a dynamically sized cpumask
  20 * at the end of the structure, the size of which depends on the maximum CPU
  21 * number the system can see. That way we allocate only as much memory for
  22 * mm_cpumask() as needed for the hundreds, or thousands of processes that
  23 * a system typically runs.
  24 *
  25 * Since there is only one init_mm in the entire system, keep it simple
  26 * and size this cpu_bitmask to NR_CPUS.
  27 */
  28struct mm_struct init_mm = {
  29        .mm_rb          = RB_ROOT,
  30        .pgd            = swapper_pg_dir,
  31        .mm_users       = ATOMIC_INIT(2),
  32        .mm_count       = ATOMIC_INIT(1),
  33        .mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
  34        .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
  35        .arg_lock       =  __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
  36        .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
  37        .user_ns        = &init_user_ns,
  38        .cpu_bitmap     = { [BITS_TO_LONGS(NR_CPUS)] = 0},
  39        INIT_MM_CONTEXT(init_mm)
  40};
  41