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/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_rb          = RB_ROOT,
  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 }