linux-kernel - [PATCH V2 5/8] arm64/mm: Check PXD_TYPE_TABLE in [p4d|pgd]

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Message-Id: <20250221044227.1145393-6-anshuman.khandual@arm.com>
Date: Fri, 21 Feb 2025 10:12:24 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: arm-kernel@...ts.infradead.org
Cc: Anshuman Khandual <anshuman.khandual@....com>,
	Marc Zyngier <maz@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	James Morse <james.morse@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Ard Biesheuvel <ardb@...nel.org>,
	Ryan Roberts <ryan.roberts@....com>,
	Mark Rutland <mark.rutland@....com>,
	kvmarm@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH V2 5/8] arm64/mm: Check PXD_TYPE_TABLE in [p4d|pgd]_bad()

Check page table entries against PXD_TYPE_TABLE on PXD_TYPE_MASK mask bits
in [p4d|pgd]_bad() while determining a table entry instead of just checking
only for PXD_TABLE_BIT.

Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Ard Biesheuvel <ardb@...nel.org>
Cc: Ryan Roberts <ryan.roberts@....com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
 arch/arm64/include/asm/pgtable.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 4485ecdffd8a..0c1691979c14 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -918,7 +918,9 @@ static inline bool mm_pud_folded(const struct mm_struct *mm)
 	pr_err("%s:%d: bad pud %016llx.\n", __FILE__, __LINE__, pud_val(e))
 
 #define p4d_none(p4d)		(pgtable_l4_enabled() && !p4d_val(p4d))
-#define p4d_bad(p4d)		(pgtable_l4_enabled() && !(p4d_val(p4d) & P4D_TABLE_BIT))
+#define p4d_bad(p4d)		(pgtable_l4_enabled() && \
+				((p4d_val(p4d) & P4D_TYPE_MASK) != \
+				 P4D_TYPE_TABLE))
 #define p4d_present(p4d)	(!p4d_none(p4d))
 
 static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
@@ -1045,7 +1047,9 @@ static inline bool mm_p4d_folded(const struct mm_struct *mm)
 	pr_err("%s:%d: bad p4d %016llx.\n", __FILE__, __LINE__, p4d_val(e))
 
 #define pgd_none(pgd)		(pgtable_l5_enabled() && !pgd_val(pgd))
-#define pgd_bad(pgd)		(pgtable_l5_enabled() && !(pgd_val(pgd) & PGD_TABLE_BIT))
+#define pgd_bad(pgd)		(pgtable_l5_enabled() && \
+				((pgd_val(pgd) & PGD_TYPE_MASK) != \
+				 PGD_TYPE_TABLE))
 #define pgd_present(pgd)	(!pgd_none(pgd))
 
 static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
-- 
2.25.1