mm/init-mm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/mm_types.h>
   3 #include <linux/rbtree.h>
   4 #include <linux/maple_tree.h>
   5 #include <linux/rwsem.h>
   6 #include <linux/spinlock.h>
   7 #include <linux/list.h>
   8 #include <linux/cpumask.h>
   9 #include <linux/mman.h>
  10 #include <linux/pgtable.h>
  11
  12 #include <linux/atomic.h>
  13 #include <linux/user_namespace.h>
  14 #include <linux/ioasid.h>
  15 #include <asm/mmu.h>
  16
  17 #ifndef INIT_MM_CONTEXT
  18 #define INIT_MM_CONTEXT(name)
  19 #endif
  20
  21 /*
  22  * For dynamically allocated mm_structs, there is a dynamically sized cpumask
  23  * at the end of the structure, the size of which depends on the maximum CPU
  24  * number the system can see. That way we allocate only as much memory for
  25  * mm_cpumask() as needed for the hundreds, or thousands of processes that
  26  * a system typically runs.
  27  *
  28  * Since there is only one init_mm in the entire system, keep it simple
  29  * and size this cpu_bitmask to NR_CPUS.
  30  */
  31 struct mm_struct init_mm = {
  32         .mm_rb          = RB_ROOT,
  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         .user_ns        = &init_user_ns,
  43         .cpu_bitmap     = CPU_BITS_NONE,
  44 #ifdef CONFIG_IOMMU_SVA
  45         .pasid          = INVALID_IOASID,
  46 #endif
  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 }