arm64/mm: Remove [PUD|PMD]_TABLE_BIT from [pud|pmd]_bad()

Semantics wise, [pud|pmd]_bad() have always implied that a given [PUD|PMD]
entry does not have a pointer to the next level page table. This had been
made clear in the commit a1c76574 ("arm64: mm: use *_sect to check for
section maps"). Hence explicitly check for a table entry rather than just
testing a single bit. This basically redefines [pud|pmd]_bad() in terms of
[pud|pmd]_table() making the semantics clear.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/1620644871-26280-1-git-send-email-anshuman.khandual@arm.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/include/asm/pgtable.h

@@ -511,13 +511,12 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 
 #define pmd_none(pmd)		(!pmd_val(pmd))
 
-#define pmd_bad(pmd)		(!(pmd_val(pmd) & PMD_TABLE_BIT))
-
 #define pmd_table(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
 				 PMD_TYPE_TABLE)
 #define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
 				 PMD_TYPE_SECT)
 #define pmd_leaf(pmd)		pmd_sect(pmd)
+#define pmd_bad(pmd)		(!pmd_table(pmd))
 
 #define pmd_leaf_size(pmd)	(pmd_cont(pmd) ? CONT_PMD_SIZE : PMD_SIZE)
 #define pte_leaf_size(pte)	(pte_cont(pte) ? CONT_PTE_SIZE : PAGE_SIZE)
@@ -604,7 +603,7 @@ 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_val(pud) & PUD_TABLE_BIT))
+#define pud_bad(pud)		(!pud_table(pud))
 #define pud_present(pud)	pte_present(pud_pte(pud))
 #define pud_leaf(pud)		pud_sect(pud)
 #define pud_valid(pud)		pte_valid(pud_pte(pud))