arm64/mm: Unify CONT_PTE_SHIFT

CONT_PTE_SHIFT actually depends on CONFIG_ARM64_CONT_SHIFT. It's
reasonable to reflect the dependency:

   * This renames CONFIG_ARM64_CONT_SHIFT to CONFIG_ARM64_CONT_PTE_SHIFT,
     so that we can introduce CONFIG_ARM64_CONT_PMD_SHIFT later.

   * CONT_{SHIFT, SIZE, MASK}, defined in page-def.h are removed as they
     are not used by anyone.

   * CONT_PTE_SHIFT is determined by CONFIG_ARM64_CONT_PTE_SHIFT.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200910095936.20307-2-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/Kconfig

@@ -211,7 +211,7 @@ config ARM64_PAGE_SHIFT
 	default 14 if ARM64_16K_PAGES
 	default 12
 
-config ARM64_CONT_SHIFT
+config ARM64_CONT_PTE_SHIFT
 	int
 	default 5 if ARM64_64K_PAGES
 	default 7 if ARM64_16K_PAGES

arch/arm64/include/asm/page-def.h

@@ -11,13 +11,8 @@
 #include <linux/const.h>
 
 /* PAGE_SHIFT determines the page size */
-/* CONT_SHIFT determines the number of pages which can be tracked together  */
 #define PAGE_SHIFT		CONFIG_ARM64_PAGE_SHIFT
-#define CONT_SHIFT		CONFIG_ARM64_CONT_SHIFT
 #define PAGE_SIZE		(_AC(1, UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-#define CONT_SIZE		(_AC(1, UL) << (CONT_SHIFT + PAGE_SHIFT))
-#define CONT_MASK		(~(CONT_SIZE-1))
-
 #endif /* __ASM_PAGE_DEF_H */

arch/arm64/include/asm/pgtable-hwdef.h

@@ -81,14 +81,12 @@
 /*
  * Contiguous page definitions.
  */
+#define CONT_PTE_SHIFT		(CONFIG_ARM64_CONT_PTE_SHIFT + PAGE_SHIFT)
 #ifdef CONFIG_ARM64_64K_PAGES
-#define CONT_PTE_SHIFT		(5 + PAGE_SHIFT)
 #define CONT_PMD_SHIFT		(5 + PMD_SHIFT)
 #elif defined(CONFIG_ARM64_16K_PAGES)
-#define CONT_PTE_SHIFT		(7 + PAGE_SHIFT)
 #define CONT_PMD_SHIFT		(5 + PMD_SHIFT)
 #else
-#define CONT_PTE_SHIFT		(4 + PAGE_SHIFT)
 #define CONT_PMD_SHIFT		(4 + PMD_SHIFT)
 #endif