arm64/mm: Check PUD_TYPE_TABLE in pud_bad()

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: Will Deacon <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Ryan Roberts <[email protected]>
Signed-off-by: Anshuman Khandual <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

Author: Ryan Roberts

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))