[PATCH 3.2 100/104] nospec: Include <asm/barrier.h> dependency

[Ben Hutchings]

3.2.101-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Dan Williams <dan.j.williams@xxxxxxxxx>

commit eb6174f6d1be16b19cfa43dac296bfed003ce1a6 upstream.

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>
[bwh: Backported to 3.2: include <asm/system.h> instead]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 include/linux/nospec.h | 1 +
 1 file changed, 1 insertion(+)

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