From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752537AbeFERD0 (ORCPT ); Tue, 5 Jun 2018 13:03:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:60264 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752481AbeFERDW (ORCPT ); Tue, 5 Jun 2018 13:03:22 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Neuling , Michael Ellerman Subject: [PATCH 4.4 02/37] powerpc/64s: Clear PCR on boot Date: Tue, 5 Jun 2018 19:01:07 +0200 Message-Id: <20180605170109.044539086@linuxfoundation.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180605170108.884872354@linuxfoundation.org> References: <20180605170108.884872354@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Neuling commit faf37c44a105f3608115785f17cbbf3500f8bc71 upstream. Clear the PCR (Processor Compatibility Register) on boot to ensure we are not running in a compatibility mode. We've seen this cause problems when a crash (and kdump) occurs while running compat mode guests. The kdump kernel then runs with the PCR set and causes problems. The symptom in the kdump kernel (also seen in petitboot after fast-reboot) is early userspace programs taking sigills on newer instructions (seen in libc). Signed-off-by: Michael Neuling Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/cpu_setup_power.S | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/powerpc/kernel/cpu_setup_power.S +++ b/arch/powerpc/kernel/cpu_setup_power.S @@ -27,6 +27,7 @@ _GLOBAL(__setup_cpu_power7) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR bl __init_LPCR bl __init_tlb_power7 @@ -40,6 +41,7 @@ _GLOBAL(__restore_cpu_power7) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR bl __init_LPCR bl __init_tlb_power7 @@ -55,6 +57,7 @@ _GLOBAL(__setup_cpu_power8) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR ori r3, r3, LPCR_PECEDH bl __init_LPCR @@ -74,6 +77,7 @@ _GLOBAL(__restore_cpu_power8) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR ori r3, r3, LPCR_PECEDH bl __init_LPCR