[PATCH v1 3/7] tools: Partial import of prefetch.h

[Yuzhuo Jing <yuzhuo@google.com>]

Import only prefetch and prefetchw but not page and range related
methods.

Signed-off-by: Yuzhuo Jing <yuzhuo@google.com>
---
 tools/include/linux/prefetch.h | 41 ++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 tools/include/linux/prefetch.h

diff --git a/tools/include/linux/prefetch.h b/tools/include/linux/prefetch.h
new file mode 100644
index 000000000000..1ed8678f4824
--- /dev/null
+++ b/tools/include/linux/prefetch.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Generic cache management functions. Everything is arch-specific,  
+ *  but this header exists to make sure the defines/functions can be
+ *  used in a generic way.
+ *
+ *  2000-11-13  Arjan van de Ven   <arjan@fenrus.demon.nl>
+ *
+ */
+
+#ifndef _LINUX_PREFETCH_H
+#define _LINUX_PREFETCH_H
+
+/*
+	prefetch(x) attempts to pre-emptively get the memory pointed to
+	by address "x" into the CPU L1 cache. 
+	prefetch(x) should not cause any kind of exception, prefetch(0) is
+	specifically ok.
+
+	prefetch() should be defined by the architecture, if not, the 
+	#define below provides a no-op define.	
+	
+	There are 2 prefetch() macros:
+	
+	prefetch(x)  	- prefetches the cacheline at "x" for read
+	prefetchw(x)	- prefetches the cacheline at "x" for write
+	
+	there is also PREFETCH_STRIDE which is the architecure-preferred 
+	"lookahead" size for prefetching streamed operations.
+	
+*/
+
+#ifndef ARCH_HAS_PREFETCH
+#define prefetch(x) __builtin_prefetch(x)
+#endif
+
+#ifndef ARCH_HAS_PREFETCHW
+#define prefetchw(x) __builtin_prefetch(x,1)
+#endif
+
+#endif
-- 
2.50.1.487.gc89ff58d15-goog