From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out5-smtp.messagingengine.com ([66.111.4.29]:55292 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716AbcEHM6V (ORCPT ); Sun, 8 May 2016 08:58:21 -0400 Received: from compute2.internal (compute2.nyi.internal [10.202.2.42]) by mailout.nyi.internal (Postfix) with ESMTP id 22264205A5 for ; Sun, 8 May 2016 08:58:20 -0400 (EDT) Subject: FAILED: patch "[PATCH] powerpc: Fix bad inline asm constraint in create_zero_mask()" failed to apply to 3.14-stable tree To: anton@samba.org, mpe@ellerman.id.au Cc: From: Date: Sun, 08 May 2016 14:58:17 +0200 Message-ID: <14627122979956@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 3.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From b4c112114aab9aff5ed4568ca5e662bb02cdfe74 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Sat, 30 Apr 2016 08:29:27 +1000 Subject: [PATCH] powerpc: Fix bad inline asm constraint in create_zero_mask() In create_zero_mask() we have: addi %1,%2,-1 andc %1,%1,%2 popcntd %0,%1 using the "r" constraint for %2. r0 is a valid register in the "r" set, but addi X,r0,X turns it into an li: li r7,-1 andc r7,r7,r0 popcntd r4,r7 Fix this by using the "b" constraint, for which r0 is not a valid register. This was found with a kernel build using gcc trunk, narrowed down to when -frename-registers was enabled at -O2. It is just luck however that we aren't seeing this on older toolchains. Thanks to Segher for working with me to find this issue. Cc: stable@vger.kernel.org Fixes: d0cebfa650a0 ("powerpc: word-at-a-time optimization for 64-bit Little Endian") Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman diff --git a/arch/powerpc/include/asm/word-at-a-time.h b/arch/powerpc/include/asm/word-at-a-time.h index e4396a7d0f7c..4afe66aa1400 100644 --- a/arch/powerpc/include/asm/word-at-a-time.h +++ b/arch/powerpc/include/asm/word-at-a-time.h @@ -82,7 +82,7 @@ static inline unsigned long create_zero_mask(unsigned long bits) "andc %1,%1,%2\n\t" "popcntd %0,%1" : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask) - : "r" (bits)); + : "b" (bits)); return leading_zero_bits; }