1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _PGTABLE_NOP4D_HACK_H
 3#define _PGTABLE_NOP4D_HACK_H
 4
 5#ifndef __ASSEMBLY__
 6#include <asm-generic/5level-fixup.h>
 7
 8#define __PAGETABLE_PUD_FOLDED 1
 9
10/*
11 * Having the pud type consist of a pgd gets the size right, and allows
12 * us to conceptually access the pgd entry that this pud is folded into
13 * without casting.
14 */
15typedef struct { pgd_t pgd; } pud_t;
16
17#define PUD_SHIFT	PGDIR_SHIFT
18#define PTRS_PER_PUD	1
19#define PUD_SIZE	(1UL << PUD_SHIFT)
20#define PUD_MASK	(~(PUD_SIZE-1))
21
22/*
23 * The "pgd_xxx()" functions here are trivial for a folded two-level
24 * setup: the pud is never bad, and a pud always exists (as it's folded
25 * into the pgd entry)
26 */
27static inline int pgd_none(pgd_t pgd)		{ return 0; }
28static inline int pgd_bad(pgd_t pgd)		{ return 0; }
29static inline int pgd_present(pgd_t pgd)	{ return 1; }
30static inline void pgd_clear(pgd_t *pgd)	{ }
31#define pud_ERROR(pud)				(pgd_ERROR((pud).pgd))
32
33#define pgd_populate(mm, pgd, pud)		do { } while (0)
34#define pgd_populate_safe(mm, pgd, pud)		do { } while (0)
35/*
36 * (puds are folded into pgds so this doesn't get actually called,
37 * but the define is needed for a generic inline function.)
38 */
39#define set_pgd(pgdptr, pgdval)	set_pud((pud_t *)(pgdptr), (pud_t) { pgdval })
40
41static inline pud_t *pud_offset(pgd_t *pgd, unsigned long address)
42{
43	return (pud_t *)pgd;
44}
45
46#define pud_val(x)				(pgd_val((x).pgd))
47#define __pud(x)				((pud_t) { __pgd(x) })
48
49#define pgd_page(pgd)				(pud_page((pud_t){ pgd }))
50#define pgd_page_vaddr(pgd)			(pud_page_vaddr((pud_t){ pgd }))
51
52/*
53 * allocating and freeing a pud is trivial: the 1-entry pud is
54 * inside the pgd, so has no extra memory associated with it.
55 */
56#define pud_alloc_one(mm, address)		NULL
57#define pud_free(mm, x)				do { } while (0)
58#define __pud_free_tlb(tlb, x, a)		do { } while (0)
59
60#undef  pud_addr_end
61#define pud_addr_end(addr, end)			(end)
62
63#endif /* __ASSEMBLY__ */
64#endif /* _PGTABLE_NOP4D_HACK_H */