1 files changed, 42 insertions, 0 deletions
diff --git a/mm/init-mm.c b/mm/init-mm.c
new file mode 100644
index 000000000..153162669
--- /dev/null
+++ b/mm/init-mm.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/mm_types.h>
+#include <linux/rbtree.h>
+#include <linux/rwsem.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/cpumask.h>
+#include <linux/mman.h>
+#include <linux/pgtable.h>
+
+#include <linux/atomic.h>
+#include <linux/user_namespace.h>
+#include <asm/mmu.h>
+
+#ifndef INIT_MM_CONTEXT
+#define INIT_MM_CONTEXT(name)
+#endif
+
+/*
+ * For dynamically allocated mm_structs, there is a dynamically sized cpumask
+ * at the end of the structure, the size of which depends on the maximum CPU
+ * number the system can see. That way we allocate only as much memory for
+ * mm_cpumask() as needed for the hundreds, or thousands of processes that
+ * a system typically runs.
+ *
+ * Since there is only one init_mm in the entire system, keep it simple
+ * and size this cpu_bitmask to NR_CPUS.
+ */
+struct mm_struct init_mm = {
+	.mm_rb		= RB_ROOT,
+	.pgd		= swapper_pg_dir,
+	.mm_users	= ATOMIC_INIT(2),
+	.mm_count	= ATOMIC_INIT(1),
+	.write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq),
+	MMAP_LOCK_INITIALIZER(init_mm)
+	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
+	.arg_lock	=  __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
+	.mmlist		= LIST_HEAD_INIT(init_mm.mmlist),
+	.user_ns	= &init_user_ns,
+	.cpu_bitmap	= CPU_BITS_NONE,
+	INIT_MM_CONTEXT(init_mm)
+};