From: Dan Williams <dan.j.williams@intel.com>
Date: Wed, 7 Feb 2018 02:22:40 +0000 (-0800)
Subject: x86/speculation: Fix up array_index_nospec_mask() asm constraint
X-Git-Tag: v4.19~1574^2~8
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=be3233fbfcb8f5acb6e3bcd0895c3ef9e100d470;p=platform%2Fkernel%2Flinux-rpi.git

x86/speculation: Fix up array_index_nospec_mask() asm constraint

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>
---

diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 30d4061..e1259f0 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -40,7 +40,7 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
 
 	asm ("cmp %1,%2; sbb %0,%0;"
 			:"=r" (mask)
-			:"r"(size),"r" (index)
+			:"g"(size),"r" (index)
 			:"cc");
 	return mask;
 }