linux-kernel - [PATCH 15/29] csky: Fixup update_mmu

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Date:   Thu, 21 Jan 2021 14:53:35 +0800
From:   guoren@...nel.org
To:     guoren@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-csky@...r.kernel.org,
        Guo Ren <guoren@...ux.alibaba.com>
Subject: [PATCH 15/29] csky: Fixup update_mmu_cache called with user io mapping

From: Guo Ren <guoren@...ux.alibaba.com>

The function update_mmu_cache could be called by user-io mapping.
There is no space of struct page in mem_map for the pte. Just
ignore the user-io mmaping in update_mmu_cache.

Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
---
 arch/csky/abiv2/cacheflush.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/csky/abiv2/cacheflush.c b/arch/csky/abiv2/cacheflush.c
index 790f1ebfba44..39c51399dd81 100644
--- a/arch/csky/abiv2/cacheflush.c
+++ b/arch/csky/abiv2/cacheflush.c
@@ -12,6 +12,9 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 	unsigned long addr;
 	struct page *page;
 
+	if (!pfn_valid(pte_pfn(*pte)))
+		return;
+
 	page = pfn_to_page(pte_pfn(*pte));
 	if (page == ZERO_PAGE(0))
 		return;
-- 
2.17.1