v4.19.13 snapshot.
diff --git a/include/linux/cache.h b/include/linux/cache.h
new file mode 100644
index 0000000..750621e
--- /dev/null
+++ b/include/linux/cache.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_CACHE_H
+#define __LINUX_CACHE_H
+
+#include <uapi/linux/kernel.h>
+#include <asm/cache.h>
+
+#ifndef L1_CACHE_ALIGN
+#define L1_CACHE_ALIGN(x) __ALIGN_KERNEL(x, L1_CACHE_BYTES)
+#endif
+
+#ifndef SMP_CACHE_BYTES
+#define SMP_CACHE_BYTES L1_CACHE_BYTES
+#endif
+
+/*
+ * __read_mostly is used to keep rarely changing variables out of frequently
+ * updated cachelines. If an architecture doesn't support it, ignore the
+ * hint.
+ */
+#ifndef __read_mostly
+#define __read_mostly
+#endif
+
+/*
+ * __ro_after_init is used to mark things that are read-only after init (i.e.
+ * after mark_rodata_ro() has been called). These are effectively read-only,
+ * but may get written to during init, so can't live in .rodata (via "const").
+ */
+#ifndef __ro_after_init
+#define __ro_after_init __attribute__((__section__(".data..ro_after_init")))
+#endif
+
+#ifndef ____cacheline_aligned
+#define ____cacheline_aligned __attribute__((__aligned__(SMP_CACHE_BYTES)))
+#endif
+
+#ifndef ____cacheline_aligned_in_smp
+#ifdef CONFIG_SMP
+#define ____cacheline_aligned_in_smp ____cacheline_aligned
+#else
+#define ____cacheline_aligned_in_smp
+#endif /* CONFIG_SMP */
+#endif
+
+#ifndef __cacheline_aligned
+#define __cacheline_aligned \
+ __attribute__((__aligned__(SMP_CACHE_BYTES), \
+ __section__(".data..cacheline_aligned")))
+#endif /* __cacheline_aligned */
+
+#ifndef __cacheline_aligned_in_smp
+#ifdef CONFIG_SMP
+#define __cacheline_aligned_in_smp __cacheline_aligned
+#else
+#define __cacheline_aligned_in_smp
+#endif /* CONFIG_SMP */
+#endif
+
+/*
+ * The maximum alignment needed for some critical structures
+ * These could be inter-node cacheline sizes/L3 cacheline
+ * size etc. Define this in asm/cache.h for your arch
+ */
+#ifndef INTERNODE_CACHE_SHIFT
+#define INTERNODE_CACHE_SHIFT L1_CACHE_SHIFT
+#endif
+
+#if !defined(____cacheline_internodealigned_in_smp)
+#if defined(CONFIG_SMP)
+#define ____cacheline_internodealigned_in_smp \
+ __attribute__((__aligned__(1 << (INTERNODE_CACHE_SHIFT))))
+#else
+#define ____cacheline_internodealigned_in_smp
+#endif
+#endif
+
+#ifndef CONFIG_ARCH_HAS_CACHE_LINE_SIZE
+#define cache_line_size() L1_CACHE_BYTES
+#endif
+
+#endif /* __LINUX_CACHE_H */