1// SPDX-License-Identifier: GPL-2.0
2#include <linux/mm_types.h>
3#include <linux/maple_tree.h>
4#include <linux/rwsem.h>
5#include <linux/spinlock.h>
6#include <linux/list.h>
7#include <linux/cpumask.h>
8#include <linux/mman.h>
9#include <linux/pgtable.h>
10
11#include <linux/atomic.h>
12#include <linux/user_namespace.h>
13#include <linux/iommu.h>
14#include <asm/mmu.h>
15
16#ifndef INIT_MM_CONTEXT
17#define INIT_MM_CONTEXT(name)
18#endif
19
20const struct vm_operations_struct vma_dummy_vm_ops;
21
22/*
23 * For dynamically allocated mm_structs, there is a dynamically sized cpumask
24 * at the end of the structure, the size of which depends on the maximum CPU
25 * number the system can see. That way we allocate only as much memory for
26 * mm_cpumask() as needed for the hundreds, or thousands of processes that
27 * a system typically runs.
28 *
29 * Since there is only one init_mm in the entire system, keep it simple
30 * and size this cpu_bitmask to NR_CPUS.
31 */
32struct mm_struct init_mm = {
33 .mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, init_mm.mmap_lock),
34 .pgd = swapper_pg_dir,
35 .mm_users = ATOMIC_INIT(2),
36 .mm_count = ATOMIC_INIT(1),
37 .write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq),
38 MMAP_LOCK_INITIALIZER(init_mm)
39 .page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
40 .arg_lock = __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
41 .mmlist = LIST_HEAD_INIT(init_mm.mmlist),
42#ifdef CONFIG_PER_VMA_LOCK
43 .mm_lock_seq = 0,
44#endif
45 .user_ns = &init_user_ns,
46 .cpu_bitmap = CPU_BITS_NONE,
47#ifdef CONFIG_IOMMU_SVA
48 .pasid = IOMMU_PASID_INVALID,
49#endif
50 INIT_MM_CONTEXT(init_mm)
51};
52
53void setup_initial_init_mm(void *start_code, void *end_code,
54 void *end_data, void *brk)
55{
56 init_mm.start_code = (unsigned long)start_code;
57 init_mm.end_code = (unsigned long)end_code;
58 init_mm.end_data = (unsigned long)end_data;
59 init_mm.brk = (unsigned long)brk;
60}
61

source code of linux/mm/init-mm.c