linux-kernel - [PATCH] arm64: KVM: marking pages as XN in Stage-2 does not care about CTR

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Date:   Mon, 12 Oct 2020 09:08:52 +0800
From:   l00484210 <limingwang@...wei.com>
To:     <catalin.marinas@....com>, <will@...nel.org>, <broonie@...nel.org>,
        <maz@...nel.org>, <suzuki.poulose@....com>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <fanhenglong@...wei.com>,
        <wanghaibin.wang@...wei.com>, <tangnianyao@...wei.com>,
        <jiangyifei@...wei.com>, <dengkai1@...wei.com>,
        <zhang.zhanghailiang@...wei.com>,
        <victor.zhangxiaofeng@...wei.com>,
        "MingWang Li" <limingwang@...wei.com>
Subject: [PATCH] arm64: KVM: marking pages as XN in Stage-2 does not care about CTR_EL0.DIC

From: MingWang Li <limingwang@...wei.com>

When testing the ARMv8.2-TTS2UXN feature, setting bits of XN is unavailable.
Because the control bit CTR_EL0.DIC is set by default on system.

But when CTR_EL0.DIC is set, software does not need to flush icache actively,
instead of clearing XN bits.The patch, the commit id of which
is 6ae4b6e0578886eb36cedbf99f04031d93f9e315, has implemented the function
of CTR_EL0.DIC.

Signed-off-by: MingWang Li <limingwang@...wei.com>
Signed-off-by: Henglong Fan <fanhenglong@...wei.com>
---
 arch/arm64/include/asm/pgtable-prot.h | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 4d867c6446c4..5feb94882bf7 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -79,17 +79,7 @@ extern bool arm64_use_ng_mappings;
 		__val;							\
 	 })
 
-#define PAGE_S2_XN							\
-	({								\
-		u64 __val;						\
-		if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC))		\
-			__val = 0;					\
-		else							\
-			__val = PTE_S2_XN;				\
-		__val;							\
-	})
-
-#define PAGE_S2			__pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PAGE_S2_XN)
+#define PAGE_S2			__pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PTE_S2_XN)
 #define PAGE_S2_DEVICE		__pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN)
 
 #define PAGE_NONE		__pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
-- 
2.19.1