xref: /linux/mm/init-mm.c (revision c1a2f7f0c06454387c2cd7b93ff1491c715a8c69)
1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0
2bb1f17b0SAlexey Dobriyan #include <linux/mm_types.h>
3bb1f17b0SAlexey Dobriyan #include <linux/rbtree.h>
4bb1f17b0SAlexey Dobriyan #include <linux/rwsem.h>
5bb1f17b0SAlexey Dobriyan #include <linux/spinlock.h>
6bb1f17b0SAlexey Dobriyan #include <linux/list.h>
7bb1f17b0SAlexey Dobriyan #include <linux/cpumask.h>
8bb1f17b0SAlexey Dobriyan 
960063497SArun Sharma #include <linux/atomic.h>
10bfedb589SEric W. Biederman #include <linux/user_namespace.h>
11bb1f17b0SAlexey Dobriyan #include <asm/pgtable.h>
12a1b200e2SHeiko Carstens #include <asm/mmu.h>
13a1b200e2SHeiko Carstens 
14a1b200e2SHeiko Carstens #ifndef INIT_MM_CONTEXT
15a1b200e2SHeiko Carstens #define INIT_MM_CONTEXT(name)
16a1b200e2SHeiko Carstens #endif
17bb1f17b0SAlexey Dobriyan 
18*c1a2f7f0SRik van Riel /*
19*c1a2f7f0SRik van Riel  * For dynamically allocated mm_structs, there is a dynamically sized cpumask
20*c1a2f7f0SRik van Riel  * at the end of the structure, the size of which depends on the maximum CPU
21*c1a2f7f0SRik van Riel  * number the system can see. That way we allocate only as much memory for
22*c1a2f7f0SRik van Riel  * mm_cpumask() as needed for the hundreds, or thousands of processes that
23*c1a2f7f0SRik van Riel  * a system typically runs.
24*c1a2f7f0SRik van Riel  *
25*c1a2f7f0SRik van Riel  * Since there is only one init_mm in the entire system, keep it simple
26*c1a2f7f0SRik van Riel  * and size this cpu_bitmask to NR_CPUS.
27*c1a2f7f0SRik van Riel  */
28bb1f17b0SAlexey Dobriyan struct mm_struct init_mm = {
29bb1f17b0SAlexey Dobriyan 	.mm_rb		= RB_ROOT,
30bb1f17b0SAlexey Dobriyan 	.pgd		= swapper_pg_dir,
31bb1f17b0SAlexey Dobriyan 	.mm_users	= ATOMIC_INIT(2),
32bb1f17b0SAlexey Dobriyan 	.mm_count	= ATOMIC_INIT(1),
33bb1f17b0SAlexey Dobriyan 	.mmap_sem	= __RWSEM_INITIALIZER(init_mm.mmap_sem),
34bb1f17b0SAlexey Dobriyan 	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
3588aa7cc6SYang Shi 	.arg_lock	=  __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
36bb1f17b0SAlexey Dobriyan 	.mmlist		= LIST_HEAD_INIT(init_mm.mmlist),
37bfedb589SEric W. Biederman 	.user_ns	= &init_user_ns,
38*c1a2f7f0SRik van Riel 	.cpu_bitmap	= { [BITS_TO_LONGS(NR_CPUS)] = 0},
39a1b200e2SHeiko Carstens 	INIT_MM_CONTEXT(init_mm)
40bb1f17b0SAlexey Dobriyan };
41