From:   Huacai Chen <chenhc@lemote.com>
To:     Ralf Baechle <ralf@linux-mips.org>
Cc:     James Hogan <james.hogan@mips.com>,
        "Steven J . Hill" <Steven.Hill@cavium.com>,
        linux-mips@linux-mips.org, Fuxin Zhang <zhangfx@lemote.com>,
        Zhangjin Wu <wuzhangjin@gmail.com>,
        Huacai Chen <chenhc@lemote.com>,
        "# 3 . 8+" <stable@vger.kernel.org>
Subject: [PATCH V5 3/8] MIPS: Ensure pmd_present() returns false after pmd_mknotpresent()
Date:   Thu, 15 Nov 2018 15:53:54 +0800
Message-Id: <1542268439-4146-4-git-send-email-chenhc@lemote.com>
In-Reply-To: <1542268439-4146-1-git-send-email-chenhc@lemote.com>
References: <1542268439-4146-1-git-send-email-chenhc@lemote.com>
Original-Recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
Errors-to: linux-mips-bounce@linux-mips.org
Precedence: bulk

This patch is borrowed from ARM64 to ensure pmd_present() returns false
after pmd_mknotpresent(). This is needed for THP.

Cc: <stable@vger.kernel.org> # 3.8+
References: 5bb1cc0ff9a6 ("arm64: Ensure pmd_present() returns false after pmd_mknotpresent()")
Reviewed-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
---
 arch/mips/include/asm/pgtable-64.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index 0036ea0..93a9dce 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -265,6 +265,11 @@ static inline int pmd_bad(pmd_t pmd)
 
 static inline int pmd_present(pmd_t pmd)
 {
+#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
+	if (unlikely(pmd_val(pmd) & _PAGE_HUGE))
+		return pmd_val(pmd) & _PAGE_PRESENT;
+#endif
+
 	return pmd_val(pmd) != (unsigned long) invalid_pte_table;
 }
 
-- 
2.7.0