v4.19.13 snapshot.
diff --git a/arch/x86/include/asm/sparsemem.h b/arch/x86/include/asm/sparsemem.h
new file mode 100644
index 0000000..1992187
--- /dev/null
+++ b/arch/x86/include/asm/sparsemem.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SPARSEMEM_H
+#define _ASM_X86_SPARSEMEM_H
+
+#ifdef CONFIG_SPARSEMEM
+/*
+ * generic non-linear memory support:
+ *
+ * 1) we will not split memory into more chunks than will fit into the flags
+ * field of the struct page
+ *
+ * SECTION_SIZE_BITS 2^n: size of each section
+ * MAX_PHYSADDR_BITS 2^n: max size of physical address space
+ * MAX_PHYSMEM_BITS 2^n: how much memory we can have in that space
+ *
+ */
+
+#ifdef CONFIG_X86_32
+# ifdef CONFIG_X86_PAE
+# define SECTION_SIZE_BITS 29
+# define MAX_PHYSADDR_BITS 36
+# define MAX_PHYSMEM_BITS 36
+# else
+# define SECTION_SIZE_BITS 26
+# define MAX_PHYSADDR_BITS 32
+# define MAX_PHYSMEM_BITS 32
+# endif
+#else /* CONFIG_X86_32 */
+# define SECTION_SIZE_BITS 27 /* matt - 128 is convenient right now */
+# define MAX_PHYSADDR_BITS (pgtable_l5_enabled() ? 52 : 44)
+# define MAX_PHYSMEM_BITS (pgtable_l5_enabled() ? 52 : 46)
+#endif
+
+#endif /* CONFIG_SPARSEMEM */
+#endif /* _ASM_X86_SPARSEMEM_H */