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 #include <linux/mman.h>
9 #include <linux/pgtable.h>
10 
11 #include <linux/atomic.h>
12 #include <linux/user_namespace.h>
13 #include <asm/mmu.h>
14 
15 #ifndef INIT_MM_CONTEXT
16 #define INIT_MM_CONTEXT(name)
17 #endif
18 
19 /*
20  * For dynamically allocated mm_structs, there is a dynamically sized cpumask
21  * at the end of the structure, the size of which depends on the maximum CPU
22  * number the system can see. That way we allocate only as much memory for
23  * mm_cpumask() as needed for the hundreds, or thousands of processes that
24  * a system typically runs.
25  *
26  * Since there is only one init_mm in the entire system, keep it simple
27  * and size this cpu_bitmask to NR_CPUS.
28  */
29 struct mm_struct init_mm = {
30 	.mm_rb		= RB_ROOT,
31 	.pgd		= swapper_pg_dir,
32 	.mm_users	= ATOMIC_INIT(2),
33 	.mm_count	= ATOMIC_INIT(1),
34 	.write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq),
35 	MMAP_LOCK_INITIALIZER(init_mm)
36 	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
37 	.arg_lock	=  __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
38 	.mmlist		= LIST_HEAD_INIT(init_mm.mmlist),
39 	.user_ns	= &init_user_ns,
40 	.cpu_bitmap	= CPU_BITS_NONE,
41 	INIT_MM_CONTEXT(init_mm)
42 };
43 
setup_initial_init_mm(void * start_code,void * end_code,void * end_data,void * brk)44 void setup_initial_init_mm(void *start_code, void *end_code,
45 			   void *end_data, void *brk)
46 {
47 	init_mm.start_code = (unsigned long)start_code;
48 	init_mm.end_code = (unsigned long)end_code;
49 	init_mm.end_data = (unsigned long)end_data;
50 	init_mm.brk = (unsigned long)brk;
51 }
52