linux-kernel - [PATCH 11/18] ARC: mm: move MMU specific bits out of entry code

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Date:   Tue, 10 Aug 2021 17:42:51 -0700
From:   Vineet Gupta <vgupta@...nel.org>
To:     linux-snps-arc@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Anshuman Khandual <anshuman.khandual@....com>,
        Mike Rapoport <rppt@...nel.org>,
        Vineet Gupta <vgupta@...nel.org>
Subject: [PATCH 11/18] ARC: mm: move MMU specific bits out of entry code

Signed-off-by: Vineet Gupta <vgupta@...nel.org>
---
 arch/arc/kernel/entry.S | 6 ------
 arch/arc/mm/tlb.c       | 3 +++
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index 2cb8dfe866b6..684efd094520 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -101,12 +101,6 @@ 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/mm/tlb.c b/arch/arc/mm/tlb.c
index b68d5798327b..34f16e0b41e6 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -813,5 +813,8 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
 		}
 	}
 
+	/* Re-enable MMU as hardware may have auto-disabled it upon exception */
+	write_aux_reg(ARC_REG_PID, read_aux_reg(ARC_REG_PID) | MMU_ENABLE);
+
 	local_irq_restore(flags);
 }
-- 
2.25.1