mm/arm: use macros to define pmd/pud helpers

It's already confusing that ARM 2-level v.s.  3-level defines SECT bit
differently on pmd/puds.  Always use a macro which is much clearer.

Link: https://lkml.kernel.org/r/20240318200404.448346-7-peterx@redhat.comSigned-off-by: Peter Xu <peterx@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Mark Salter <msalter@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm/include/asm/pgtable-2level.h

@@ -213,8 +213,8 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
 
 #define pmd_pfn(pmd)		(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
 
-#define pmd_leaf(pmd)		(pmd_val(pmd) & 2)
-#define pmd_bad(pmd)		(pmd_val(pmd) & 2)
+#define pmd_leaf(pmd)		(pmd_val(pmd) & PMD_TYPE_SECT)
+#define pmd_bad(pmd)		pmd_leaf(pmd)
 #define pmd_present(pmd)	(pmd_val(pmd))
 
 #define copy_pmd(pmdpd,pmdps)		\

arch/arm/include/asm/pgtable-3level-hwdef.h

@@ -14,6 +14,7 @@
  * + Level 1/2 descriptor
  *   - common
  */
+#define PUD_TABLE_BIT		(_AT(pmdval_t, 1) << 1)
 #define PMD_TYPE_MASK		(_AT(pmdval_t, 3) << 0)
 #define PMD_TYPE_FAULT		(_AT(pmdval_t, 0) << 0)
 #define PMD_TYPE_TABLE		(_AT(pmdval_t, 3) << 0)

arch/arm/include/asm/pgtable-3level.h

@@ -112,7 +112,7 @@
 #ifndef __ASSEMBLY__
 
 #define pud_none(pud)		(!pud_val(pud))
-#define pud_bad(pud)		(!(pud_val(pud) & 2))
+#define pud_bad(pud)		(!(pud_val(pud) & PUD_TABLE_BIT))
 #define pud_present(pud)	(pud_val(pud))
 #define pmd_table(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
 						 PMD_TYPE_TABLE)
@@ -137,7 +137,7 @@ static inline pmd_t *pud_pgtable(pud_t pud)
 	return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
 }
 
-#define pmd_bad(pmd)		(!(pmd_val(pmd) & 2))
+#define pmd_bad(pmd)		(!(pmd_val(pmd) & PMD_TABLE_BIT))
 
 #define copy_pmd(pmdpd,pmdps)		\
 	do {				\