4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Woodhouse <d...@amazon.co.uk>


(cherry picked from commit 66f793099a636862a71c59d4a6ba91387b155e0c)

There's no point in building init code with retpolines, since it runs before
any potentially hostile userspace does. And before the retpoline is actually
ALTERNATIVEd into place, for much of it.

Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: karah...@amazon.de
Cc: pet...@infradead.org
Cc: b...@alien8.de
Link: 
https://lkml.kernel.org/r/1517484441-1420-2-git-send-email-d...@amazon.co.uk
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 include/linux/init.h |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -4,6 +4,13 @@
 #include <linux/compiler.h>
 #include <linux/types.h>
 
+/* Built-in __init functions needn't be compiled with retpoline */
+#if defined(RETPOLINE) && !defined(MODULE)
+#define __noretpoline __attribute__((indirect_branch("keep")))
+#else
+#define __noretpoline
+#endif
+
 /* These macros are used to mark some functions or 
  * initialized data (doesn't apply to uninitialized data)
  * as `initialization' functions. The kernel can take this
@@ -39,7 +46,7 @@
 
 /* These are for everybody (although not all archs will actually
    discard it in modules) */
-#define __init         __section(.init.text) __cold notrace __latent_entropy
+#define __init         __section(.init.text) __cold notrace __latent_entropy 
__noretpoline
 #define __initdata     __section(.init.data)
 #define __initconst    __section(.init.rodata)
 #define __exitdata     __section(.exit.data)


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