linux-kernel - [PATCH V2 6/8] arm64/mm: Check PUD_TYPE_TABLE in pud

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Message-Id: <20250221044227.1145393-7-anshuman.khandual@arm.com>
Date: Fri, 21 Feb 2025 10:12:25 +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 6/8] arm64/mm: Check PUD_TYPE_TABLE in pud_bad()

From: Ryan Roberts <ryan.roberts@....com>

pud_bad() is currently defined in terms of pud_table(). Although for some
configs, pud_table() is hard-coded to true i.e. when using 64K base pages
or when page table levels are less than 3.

pud_bad() is intended to check that the pud is configured correctly. Hence
let's open-code the same check that the full version of pud_table() uses
into pud_bad(). Then it always performs the check regardless of the config.

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: Ryan Roberts <ryan.roberts@....com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
 arch/arm64/include/asm/pgtable.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 0c1691979c14..d16f514bde0f 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -827,7 +827,8 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 	pr_err("%s:%d: bad pmd %016llx.\n", __FILE__, __LINE__, pmd_val(e))
 
 #define pud_none(pud)		(!pud_val(pud))
-#define pud_bad(pud)		(!pud_table(pud))
+#define pud_bad(pud)		((pud_val(pud) & PUD_TYPE_MASK) != \
+				 PUD_TYPE_TABLE)
 #define pud_present(pud)	pte_present(pud_pte(pud))
 #ifndef __PAGETABLE_PMD_FOLDED
 #define pud_leaf(pud)		(pud_present(pud) && !pud_table(pud))
-- 
2.25.1