Patch "compiler-intel: fix wrong compiler barrier() macro" has been added to the 4.1-stable tree

Patch "compiler-intel: fix wrong compiler barrier() macro" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    compiler-intel: fix wrong compiler barrier() macro

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     compiler-intel-fix-wrong-compiler-barrier-macro.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b86a50c3b5414eafdbee7f34af4a201a4a7817c2 Mon Sep 17 00:00:00 2001
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 25 Jun 2015 15:01:05 -0700
Subject: compiler-intel: fix wrong compiler barrier() macro

From: Daniel Borkmann <daniel@iogearbox.net>

commit b86a50c3b5414eafdbee7f34af4a201a4a7817c2 upstream.

Cleanup commit 73679e508201 ("compiler-intel.h: Remove duplicate
definition") removed the double definition of __memory_barrier()
intrinsics.

However, in doing so, it also removed the preceding #undef barrier by
accident, meaning, the actual barrier() macro from compiler-gcc.h with
inline asm is still in place as __GNUC__ is provided.

Subsequently, barrier() can never be defined as __memory_barrier() from
compiler.h since it already has a definition in place and if we trust
the comment in compiler-intel.h, ecc doesn't support gcc specific asm
statements.

I don't have an ecc at hand (unsure if that's still used in the field?)
and only found this by accident during code review, a revert of that
cleanup would be simplest option.

Fixes: 73679e508201 ("compiler-intel.h: Remove duplicate definition")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Cc: Pranith Kumar <bobby.prani@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: mancha security <mancha1@zoho.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/linux/compiler-intel.h |    2 ++
 1 file changed, 2 insertions(+)

--- a/include/linux/compiler-intel.h
+++ b/include/linux/compiler-intel.h
@@ -13,10 +13,12 @@
 /* Intel ECC compiler doesn't support gcc specific asm stmts.
  * It uses intrinsics to do the equivalent things.
  */
+#undef barrier
 #undef barrier_data
 #undef RELOC_HIDE
 #undef OPTIMIZER_HIDE_VAR
 
+#define barrier() __memory_barrier()
 #define barrier_data(ptr) barrier()
 
 #define RELOC_HIDE(ptr, off)					\


Patches currently in stable-queue which might be from daniel@iogearbox.net are

queue-4.1/compiler-intel-fix-wrong-compiler-barrier-macro.patch