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
9typedef struct { pgd_t pgd; } p4d_t;
10
11#define P4D_SHIFT PGDIR_SHIFT
12#define PTRS_PER_P4D 1
13#define P4D_SIZE (1UL << P4D_SHIFT)
14#define P4D_MASK (~(P4D_SIZE-1))
15
16/*
17 * The "pgd_xxx()" functions here are trivial for a folded two-level
18 * setup: the p4d is never bad, and a p4d always exists (as it's folded
19 * into the pgd entry)
20 */
21static inline int pgd_none(pgd_t pgd) { return 0; }
22static inline int pgd_bad(pgd_t pgd) { return 0; }
23static inline int pgd_present(pgd_t pgd) { return 1; }
24static inline void pgd_clear(pgd_t *pgd) { }
25#define p4d_ERROR(p4d) (pgd_ERROR((p4d).pgd))
26
27#define pgd_populate(mm, pgd, p4d) do { } while (0)
28#define pgd_populate_safe(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
35static 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) ((unsigned long)(p4d_pgtable((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

source code of linux/include/asm-generic/pgtable-nop4d.h