xref: /linux/mm/init-mm.c (revision aece2094e34e602f37403dda028f464bb41da50c)
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 
20 const 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  */
32 struct 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 	INIT_MM_CONTEXT(init_mm)
48 };
49 
50 void setup_initial_init_mm(void *start_code, void *end_code,
51 			   void *end_data, void *brk)
52 {
53 	init_mm.start_code = (unsigned long)start_code;
54 	init_mm.end_code = (unsigned long)end_code;
55 	init_mm.end_data = (unsigned long)end_data;
56 	init_mm.brk = (unsigned long)brk;
57 }
58