xref: /openbmc/linux/mm/init-mm.c (revision 78289b4a)
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  	MMAP_LOCK_INITIALIZER(init_mm)
35  	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
36  	.arg_lock	=  __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
37  	.mmlist		= LIST_HEAD_INIT(init_mm.mmlist),
38  	.user_ns	= &init_user_ns,
39  	.cpu_bitmap	= CPU_BITS_NONE,
40  	INIT_MM_CONTEXT(init_mm)
41  };
42