arm64/mm: define ptdesc_t

Define ptdesc_t type which describes the basic page table descriptor
layout on arm64 platform. Subsequently all level specific pxxval_t
descriptors are derived from ptdesc_t thus establishing a common original
format, which can also be appropriate for page table entries, masks and
protection values etc which are used at all page table levels.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Anshuman Khandual <[e-mail]>
Suggested-by: Ryan Roberts <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Ard Biesheuvel <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Gerald Schaefer <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Nicholas Piggin <[e-mail]>
Cc: Palmer Dabbelt <[e-mail]>
Cc: Paul Walmsley <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

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

···
 
 #include <asm/types.h>
 
-typedef u64 pteval_t;
-typedef u64 pmdval_t;
-typedef u64 pudval_t;
-typedef u64 p4dval_t;
-typedef u64 pgdval_t;
+/*
+ * Page Table Descriptor
+ *
+ * Generic page table descriptor format from which
+ * all level specific descriptors can be derived.
+ */
+typedef u64 ptdesc_t;
+
+typedef ptdesc_t pteval_t;
+typedef ptdesc_t pmdval_t;
+typedef ptdesc_t pudval_t;
+typedef ptdesc_t p4dval_t;
+typedef ptdesc_t pgdval_t;
 
 /*
  * These are used to make use of C type-checking..
···
 #define pgd_val(x)	((x).pgd)
 #define __pgd(x)	((pgd_t) { (x) } )
 
-typedef struct { pteval_t pgprot; } pgprot_t;
+typedef struct { ptdesc_t pgprot; } pgprot_t;
 #define pgprot_val(x)	((x).pgprot)
 #define __pgprot(x)	((pgprot_t) { (x) } )
 

arch/arm64/include/asm/ptdump.h

···
 };
 
 struct ptdump_prot_bits {
-	u64		mask;
-	u64		val;
+	ptdesc_t	mask;
+	ptdesc_t	val;
 	const char	*set;
 	const char	*clear;
 };
···
 	const struct ptdump_prot_bits *bits;
 	char name[4];
 	int num;
-	u64 mask;
+	ptdesc_t mask;
 };
 
 /*
···
 	const struct mm_struct *mm;
 	unsigned long start_address;
 	int level;
-	u64 current_prot;
+	ptdesc_t current_prot;
 	bool check_wx;
 	unsigned long wx_pages;
 	unsigned long uxn_pages;

arch/arm64/kernel/efi.c

···
  * executable, everything else can be mapped with the XN bits
  * set. Also take the new (optional) RO/XP bits into account.
  */
-static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
+static __init ptdesc_t create_mapping_protection(efi_memory_desc_t *md)
 {
 	u64 attr = md->attribute;
 	u32 type = md->type;
···
 
 int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
 {
-	pteval_t prot_val = create_mapping_protection(md);
+	ptdesc_t prot_val = create_mapping_protection(md);
 	bool page_mappings_only = (md->type == EFI_RUNTIME_SERVICES_CODE ||
 				   md->type == EFI_RUNTIME_SERVICES_DATA);
 

arch/arm64/kernel/pi/map_kernel.c

···
 static void __init remap_idmap_for_lpa2(void)
 {
 	/* clear the bits that change meaning once LPA2 is turned on */
-	pteval_t mask = PTE_SHARED;
+	ptdesc_t mask = PTE_SHARED;
 
 	/*
 	 * We have to clear bits [9:8] in all block or page descriptors in the

arch/arm64/kernel/pi/map_range.c

···
 		      int level, pte_t *tbl, bool may_use_cont, u64 va_offset)
 {
 	u64 cmask = (level == 3) ? CONT_PTE_SIZE - 1 : U64_MAX;
-	pteval_t protval = pgprot_val(prot) & ~PTE_TYPE_MASK;
+	ptdesc_t protval = pgprot_val(prot) & ~PTE_TYPE_MASK;
 	int lshift = (3 - level) * PTDESC_TABLE_SHIFT;
 	u64 lmask = (PAGE_SIZE << lshift) - 1;
 
···
 	}
 }
 
-asmlinkage u64 __init create_init_idmap(pgd_t *pg_dir, pteval_t clrmask)
+asmlinkage u64 __init create_init_idmap(pgd_t *pg_dir, ptdesc_t clrmask)
 {
 	u64 ptep = (u64)pg_dir + PAGE_SIZE;
 	pgprot_t text_prot = PAGE_KERNEL_ROX;

arch/arm64/kernel/pi/pi.h

···
 
 asmlinkage void early_map_kernel(u64 boot_status, void *fdt);
 
-asmlinkage u64 create_init_idmap(pgd_t *pgd, pteval_t clrmask);
+asmlinkage u64 create_init_idmap(pgd_t *pgd, ptdesc_t clrmask);

arch/arm64/mm/mmap.c

···
 
 pgprot_t vm_get_page_prot(unsigned long vm_flags)
 {
-	pteval_t prot;
+	ptdesc_t prot;
 
 	/* Short circuit GCS to avoid bloating the table. */
 	if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) {

arch/arm64/mm/ptdump.c

···
 	struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
 	struct ptdump_pg_level *pg_level = st->pg_level;
 	static const char units[] = "KMGTPE";
-	u64 prot = 0;
+	ptdesc_t prot = 0;
 
 	/* check if the current level has been folded dynamically */
 	if (st->mm && ((level == 1 && mm_p4d_folded(st->mm)) ||