Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752331AbdIASGV (ORCPT ); Fri, 1 Sep 2017 14:06:21 -0400 Received: from smtprelay.synopsys.com ([198.182.47.9]:38653 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752265AbdIASGU (ORCPT ); Fri, 1 Sep 2017 14:06:20 -0400 From: Vineet Gupta To: CC: , , Vineet Gupta Subject: [PATCH] ARC: Machine Check Exception: enable MMU in single place Date: Fri, 1 Sep 2017 11:06:02 -0700 Message-ID: <1504289162-25977-1-git-send-email-vgupta@synopsys.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.12.196.101] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2079 Lines: 65 Machine check Exception is handled in distinc ways depending on cause - Duplicate TLB Entry (relevent mostly for ARC700) - everything else Currently we re-enable MMU seperately for each of these cases, which can be consolidated by dign this before we fork off the handling in low level handler. Signed-off-by: Vineet Gupta --- arch/arc/kernel/entry.S | 6 ++++++ arch/arc/kernel/traps.c | 6 ------ arch/arc/mm/tlb.c | 3 --- 3 files changed, 6 insertions(+), 9 deletions(-) diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 1eea99beecc3..85d9ea4a0acc 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -92,6 +92,12 @@ ENTRY(EV_MachineCheck) lr r0, [efa] mov r1, sp + ; hardware auto-disables MMU, re-enable it to allow kernel vaddr + ; access for say stack unwinding of modules for crash dumps + lr r3, [ARC_REG_PID] + or r3, r3, MMU_ENABLE + sr r3, [ARC_REG_PID] + lsr r3, r2, 8 bmsk r3, r3, 7 brne r3, ECR_C_MCHK_DUP_TLB, 1f diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c index b636dfe8ee9e..b03daa7a9a2b 100644 --- a/arch/arc/kernel/traps.c +++ b/arch/arc/kernel/traps.c @@ -105,12 +105,6 @@ int do_misaligned_access(unsigned long address, struct pt_regs *regs, */ void do_machine_check_fault(unsigned long address, struct pt_regs *regs) { - /* - * Hardware auto-disables MMU upon this exception hence re-enabled - * for ksym lookup in modules to work (in kernel vaddr space) - */ - write_aux_reg(ARC_REG_PID, MMU_ENABLE | read_aux_reg(ARC_REG_PID)); - die("Unhandled Machine Check Exception", regs, address); } diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c index edc59a0a9c9b..8ceefbf72fb0 100644 --- a/arch/arc/mm/tlb.c +++ b/arch/arc/mm/tlb.c @@ -908,9 +908,6 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address, local_irq_save(flags); - /* re-enable the MMU */ - write_aux_reg(ARC_REG_PID, MMU_ENABLE | read_aux_reg(ARC_REG_PID)); - /* loop thru all sets of TLB */ for (set = 0; set < mmu->sets; set++) { -- 2.7.4