linux-kernel - [tip:x86/pti] x86/speculation: Fix up array_index_nospec

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Date:   Wed, 14 Feb 2018 16:27:34 -0800
From:   tip-bot for Dan Williams <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, peterz@...radead.org, torvalds@...ux-foundation.org,
        dan.j.williams@...el.com, tglx@...utronix.de, mingo@...nel.org,
        luto@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip:x86/pti] x86/speculation: Fix up array_index_nospec_mask() asm
 constraint

Commit-ID:  be3233fbfcb8f5acb6e3bcd0895c3ef9e100d470
Gitweb:     https://git.kernel.org/tip/be3233fbfcb8f5acb6e3bcd0895c3ef9e100d470
Author:     Dan Williams <dan.j.williams@...el.com>
AuthorDate: Tue, 6 Feb 2018 18:22:40 -0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 15 Feb 2018 01:15:50 +0100

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@...ux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/151797010204.1289.1510000292250184993.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/barrier.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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;
 }