Patch "x86/speculation: Fix up array_index_nospec_mask() asm constraint" has been added to the 4.9-stable tree

Patch "x86/speculation: Fix up array_index_nospec_mask() asm constraint" has been added to the 4.9-stable tree

[gregkh]

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

    x86/speculation: Fix up array_index_nospec_mask() asm constraint

to the 4.9-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:
     x86-speculation-fix-up-array_index_nospec_mask-asm-constraint.patch
and it can be found in the queue-4.9 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 be3233fbfcb8f5acb6e3bcd0895c3ef9e100d470 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Tue, 6 Feb 2018 18:22:40 -0800
Subject: x86/speculation: Fix up array_index_nospec_mask() asm constraint

From: Dan Williams <dan.j.williams@intel.com>

commit be3233fbfcb8f5acb6e3bcd0895c3ef9e100d470 upstream.

Allow the compiler to handle @size as an immediate value or memory
directly rather than allocating a register.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/151797010204.1289.1510000292250184993.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/include/asm/barrier.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -39,7 +39,7 @@ static inline unsigned long array_index_
 
 	asm ("cmp %1,%2; sbb %0,%0;"
 			:"=r" (mask)
-			:"r"(size),"r" (index)
+			:"g"(size),"r" (index)
 			:"cc");
 	return mask;
 }


Patches currently in stable-queue which might be from dan.j.williams@intel.com are

queue-4.9/nospec-move-array_index_nospec-parameter-checking-into-separate-macro.patch
queue-4.9/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch
queue-4.9/x86-speculation-add-asm-msr-index.h-dependency.patch
queue-4.9/x86-speculation-update-speculation-control-microcode-blacklist.patch
queue-4.9/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch
queue-4.9/x86-speculation-fix-up-array_index_nospec_mask-asm-constraint.patch
queue-4.9/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch
queue-4.9/x86-speculation-clean-up-various-spectre-related-details.patch
queue-4.9/x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch