[tip:x86/pti] nospec: Include <asm/barrier.h> dependency

[tip-bot for Dan Williams]

Commit-ID:  eb6174f6d1be16b19cfa43dac296bfed003ce1a6
Gitweb:     https://git.kernel.org/tip/eb6174f6d1be16b19cfa43dac296bfed003ce1a6
Author:     Dan Williams <dan.j.williams@xxxxxxxxx>
AuthorDate: Fri, 16 Feb 2018 13:20:54 -0800
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sat, 17 Feb 2018 08:40:59 +0100

nospec: Include <asm/barrier.h> dependency

The nospec.h header expects the per-architecture header file
<asm/barrier.h> to optionally define array_index_mask_nospec(). Include
that dependency to prevent inadvertent fallback to the default
array_index_mask_nospec() implementation.

The default implementation may not provide a full mitigation
on architectures that perform data value speculation.

Reported-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/151881605404.17395.1341935530792574707.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/linux/nospec.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/nospec.h b/include/linux/nospec.h
index 172a19d..e791ebc 100644
--- a/include/linux/nospec.h
+++ b/include/linux/nospec.h
@@ -5,6 +5,7 @@
 
 #ifndef _LINUX_NOSPEC_H
 #define _LINUX_NOSPEC_H
+#include <asm/barrier.h>
 
 /**
  * array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise