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