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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
	Will Deacon <will@kernel.org>, Mark Brown <broonie@kernel.org>,
	kernel-team@android.com
Subject: [PATCH] arm64: pgtable: Clear the GP bit for non-executable kernel pages
Date: Mon, 15 Jun 2020 16:46:42 +0100	[thread overview]
Message-ID: <20200615154642.3579-1-will@kernel.org> (raw)

Commit cca98e9f8b5e ("mm: enforce that vmap can't map pages executable")
introduced 'pgprot_nx(prot)' for arm64 but colliding silently with the
BTI support during the merge window, which endeavours to clear the GP
bit for non-executable kernel mappings in set_memory_nx().

For consistency between the two APIs, clear the GP bit in pgprot_nx().

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/include/asm/pgtable.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 6dbd267ab931..758e2d1577d0 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -416,7 +416,7 @@ static inline pmd_t pmd_mkdevmap(pmd_t pmd)
 	__pgprot((pgprot_val(prot) & ~(mask)) | (bits))
 
 #define pgprot_nx(prot) \
-	__pgprot_modify(prot, 0, PTE_PXN)
+	__pgprot_modify(prot, PTE_MAYBE_GP, PTE_PXN)
 
 /*
  * Mark the prot value as uncacheable and unbufferable.
-- 
2.27.0.290.gba653c62da-goog


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             reply	other threads:[~2020-06-15 15:47 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15 15:46 Will Deacon [this message]
2020-06-15 16:19 ` [PATCH] arm64: pgtable: Clear the GP bit for non-executable kernel pages Mark Brown
2020-06-16  8:45 ` Mark Rutland

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