1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _PGTABLE_NOP4D_H
3 #define _PGTABLE_NOP4D_H
4 
5 #ifndef __ASSEMBLY__
6 
7 #define __PAGETABLE_P4D_FOLDED 1
8 
9 typedef struct { pgd_t pgd; } p4d_t;
10 
11 #define P4D_SHIFT		PGDIR_SHIFT
12 #define MAX_PTRS_PER_P4D	1
13 #define PTRS_PER_P4D		1
14 #define P4D_SIZE		(1UL << P4D_SHIFT)
15 #define P4D_MASK		(~(P4D_SIZE-1))
16 
17 /*
18  * The "pgd_xxx()" functions here are trivial for a folded two-level
19  * setup: the p4d is never bad, and a p4d always exists (as it's folded
20  * into the pgd entry)
21  */
pgd_none(pgd_t pgd)22 static inline int pgd_none(pgd_t pgd)		{ return 0; }
pgd_bad(pgd_t pgd)23 static inline int pgd_bad(pgd_t pgd)		{ return 0; }
pgd_present(pgd_t pgd)24 static inline int pgd_present(pgd_t pgd)	{ return 1; }
pgd_clear(pgd_t * pgd)25 static inline void pgd_clear(pgd_t *pgd)	{ }
26 #define p4d_ERROR(p4d)				(pgd_ERROR((p4d).pgd))
27 
28 #define pgd_populate(mm, pgd, p4d)		do { } while (0)
29 /*
30  * (p4ds are folded into pgds so this doesn't get actually called,
31  * but the define is needed for a generic inline function.)
32  */
33 #define set_pgd(pgdptr, pgdval)	set_p4d((p4d_t *)(pgdptr), (p4d_t) { pgdval })
34 
p4d_offset(pgd_t * pgd,unsigned long address)35 static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
36 {
37 	return (p4d_t *)pgd;
38 }
39 
40 #define p4d_val(x)				(pgd_val((x).pgd))
41 #define __p4d(x)				((p4d_t) { __pgd(x) })
42 
43 #define pgd_page(pgd)				(p4d_page((p4d_t){ pgd }))
44 #define pgd_page_vaddr(pgd)			(p4d_page_vaddr((p4d_t){ pgd }))
45 
46 /*
47  * allocating and freeing a p4d is trivial: the 1-entry p4d is
48  * inside the pgd, so has no extra memory associated with it.
49  */
50 #define p4d_alloc_one(mm, address)		NULL
51 #define p4d_free(mm, x)				do { } while (0)
52 #define __p4d_free_tlb(tlb, x, a)		do { } while (0)
53 
54 #undef  p4d_addr_end
55 #define p4d_addr_end(addr, end)			(end)
56 
57 #endif /* __ASSEMBLY__ */
58 #endif /* _PGTABLE_NOP4D_H */
59