From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755074AbbHEWEi (ORCPT ); Wed, 5 Aug 2015 18:04:38 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38642 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932173AbbHEVu1 (ORCPT ); Wed, 5 Aug 2015 17:50:27 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Martin Schwidefsky , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 067/107] s390/sclp: clear upper register halves in _sclp_print_early Date: Wed, 5 Aug 2015 14:48:59 -0700 Message-Id: <1438811379-384-68-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438811379-384-1-git-send-email-kamal@canonical.com> References: <1438811379-384-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky commit f9c87a6f46d508eae0d9ae640be98d50f237f827 upstream. If the kernel is compiled with gcc 5.1 and the XZ compression option the decompress_kernel function calls _sclp_print_early in 64-bit mode while the content of the upper register half of %r6 is non-zero. This causes a specification exception on the servc instruction in _sclp_servc. The _sclp_print_early function saves and restores the upper registers halves but it fails to clear them for the 31-bit code of the mini sclp driver. Signed-off-by: Martin Schwidefsky Signed-off-by: Kamal Mostafa --- arch/s390/kernel/sclp.S | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/s390/kernel/sclp.S b/arch/s390/kernel/sclp.S index a41f2c9..a0c4e76 100644 --- a/arch/s390/kernel/sclp.S +++ b/arch/s390/kernel/sclp.S @@ -277,6 +277,8 @@ ENTRY(_sclp_print_early) jno .Lesa2 ahi %r15,-80 stmh %r6,%r15,96(%r15) # store upper register halves + basr %r13,0 + lmh %r0,%r15,.Lzeroes-.(%r13) # clear upper register halves .Lesa2: #endif lr %r10,%r2 # save string pointer @@ -300,6 +302,8 @@ ENTRY(_sclp_print_early) #endif lm %r6,%r15,120(%r15) # restore registers br %r14 +.Lzeroes: + .fill 64,4,0 .LwritedataS4: .long 0x00760005 # SCLP command for write data -- 1.9.1