From d3ea79527757ba65b3ee08e10c59a3c84f34e4bf Mon Sep 17 00:00:00 2001
From: Steve Capper <steve.capper@arm.com>
Date: Tue, 22 Aug 2017 11:42:41 +0100
Subject: [PATCH] arm64: hugetlb: set_huge_pte_at Add WARN_ON on !pte_present
This patch adds a WARN_ON to set_huge_pte_at as the accessor assumes
that entries to be written down are all present. (There are separate
accessors to clear huge ptes).
We will need to handle the !pte_present case where memory offlining
is used on hugetlb pages. swap and migration entries will be supplied
to set_huge_pte_at in this case.
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
arch/arm64/mm/hugetlbpage.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 656e0ece2289..7b61e4833432 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -67,6 +67,12 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
unsigned long pfn;
pgprot_t hugeprot;
+ /*
+ * Code needs to be expanded to handle huge swap and migration
+ * entries. Needed for HUGETLB and MEMORY_FAILURE.
+ */
+ WARN_ON(!pte_present(pte));
+
if (!pte_cont(pte)) {
set_pte_at(mm, addr, ptep, pte);
return;
--
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