From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42978 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750883AbcEHNBI (ORCPT ); Sun, 8 May 2016 09:01:08 -0400 Subject: Patch "powerpc: Fix bad inline asm constraint in create_zero_mask()" has been added to the 4.4-stable tree To: anton@samba.org, gregkh@linuxfoundation.org, mpe@ellerman.id.au Cc: , From: Date: Sun, 08 May 2016 15:00:55 +0200 Message-ID: <14627124554084@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: This is a note to let you know that I've just added the patch titled powerpc: Fix bad inline asm constraint in create_zero_mask() to the 4.4-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: powerpc-fix-bad-inline-asm-constraint-in-create_zero_mask.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From b4c112114aab9aff5ed4568ca5e662bb02cdfe74 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Sat, 30 Apr 2016 08:29:27 +1000 Subject: powerpc: Fix bad inline asm constraint in create_zero_mask() From: Anton Blanchard commit b4c112114aab9aff5ed4568ca5e662bb02cdfe74 upstream. 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. Fixes: d0cebfa650a0 ("powerpc: word-at-a-time optimization for 64-bit Little Endian") Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/include/asm/word-at-a-time.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- 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_ "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; } Patches currently in stable-queue which might be from anton@samba.org are queue-4.4/powerpc-fix-bad-inline-asm-constraint-in-create_zero_mask.patch