From 0b89ede629637c03b9a728fb08bfe6ed51de9be7 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Thu, 31 Aug 2017 12:30:54 +0200
Subject: [PATCH] s390/mm: fork vs. 5 level page tabel
The mm->context.asce field of a new process is not set up correctly
in case of a fork with a 5 level page table.
Add the missing case to init_new_context().
Fixes: 1aea9b3f9210 ("s390/mm: implement 5 level pages tables")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/include/asm/mmu_context.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 4541ac44b35f0..24bc41622a983 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -44,6 +44,11 @@ static inline int init_new_context(struct task_struct *tsk,
mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS | _ASCE_TYPE_REGION3;
break;
+ case -PAGE_SIZE:
+ /* forked 5-level task, set new asce with new_mm->pgd */
+ mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+ _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
+ break;
case 1UL << 53:
/* forked 4-level task, set new asce with new mm->pgd */
mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
--
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