xref: /openbmc/linux/mm/init-mm.c (revision 6008105b4f4e470da0e9159a3a74ca7ff6e869ba)
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/ioasid.h>
14  #include <asm/mmu.h>
15  
16  #ifndef INIT_MM_CONTEXT
17  #define INIT_MM_CONTEXT(name)
18  #endif
19  
20  /*
21   * For dynamically allocated mm_structs, there is a dynamically sized cpumask
22   * at the end of the structure, the size of which depends on the maximum CPU
23   * number the system can see. That way we allocate only as much memory for
24   * mm_cpumask() as needed for the hundreds, or thousands of processes that
25   * a system typically runs.
26   *
27   * Since there is only one init_mm in the entire system, keep it simple
28   * and size this cpu_bitmask to NR_CPUS.
29   */
30  struct mm_struct init_mm = {
31  	.mm_mt		= MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, init_mm.mmap_lock),
32  	.pgd		= swapper_pg_dir,
33  	.mm_users	= ATOMIC_INIT(2),
34  	.mm_count	= ATOMIC_INIT(1),
35  	.write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq),
36  	MMAP_LOCK_INITIALIZER(init_mm)
37  	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
38  	.arg_lock	=  __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
39  	.mmlist		= LIST_HEAD_INIT(init_mm.mmlist),
40  	.user_ns	= &init_user_ns,
41  	.cpu_bitmap	= CPU_BITS_NONE,
42  #ifdef CONFIG_IOMMU_SVA
43  	.pasid		= INVALID_IOASID,
44  #endif
45  	INIT_MM_CONTEXT(init_mm)
46  };
47  
48  void setup_initial_init_mm(void *start_code, void *end_code,
49  			   void *end_data, void *brk)
50  {
51  	init_mm.start_code = (unsigned long)start_code;
52  	init_mm.end_code = (unsigned long)end_code;
53  	init_mm.end_data = (unsigned long)end_data;
54  	init_mm.brk = (unsigned long)brk;
55  }
56