From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751712AbdFEKO5 (ORCPT ); Mon, 5 Jun 2017 06:14:57 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:35900 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751589AbdFEKOx (ORCPT ); Mon, 5 Jun 2017 06:14:53 -0400 From: Hoeun Ryu To: Russell King Cc: Hoeun Ryu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCHv2] arm: LPAE: kexec: clear TTBCR.T1SZ explicitly when PHYS_OFFSET > PAGE_OFFSET Date: Mon, 5 Jun 2017 19:06:26 +0900 Message-Id: <1496657199-29589-1-git-send-email-hoeun.ryu@gmail.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Clearing TTBCR.T1SZ explicitly when kernel runs on a configuration of PHYS_OFFSET > PAGE_OFFSET. Reading TTBCR in early boot stage might returns the value of the previous kernel's configuration, especially in case of kexec. For example, if normal kernel (first kernel) had run on a configuration of PHYS_OFFSET <= PAGE_OFFSET and crash kernel (second kernel) is running on a configuration PHYS_OFFSET > PAGE_OFFSET, which can happen because it depends on the reserved area for crash kernel, reading TTBCR and using the value without clearing TTBCR.T1SZ might risky because the value doesn't have a reset value for TTBCR.T1SZ. Signed-off-by: Hoeun Ryu --- arch/arm/mm/proc-v7-3level.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S index 5e5720e..81404b8 100644 --- a/arch/arm/mm/proc-v7-3level.S +++ b/arch/arm/mm/proc-v7-3level.S @@ -140,6 +140,7 @@ ENDPROC(cpu_v7_set_pte_ext) * otherwise booting secondary CPUs would end up using TTBR1 for the * identity mapping set up in TTBR0. */ + bichi \tmp, \tmp, #(7 << 16) @ clear TTBCR.T1SZ orrls \tmp, \tmp, #TTBR1_SIZE @ TTBCR.T1SZ mcr p15, 0, \tmp, c2, c0, 2 @ TTBCR mov \tmp, \ttbr1, lsr #20 -- 2.7.4