LXR linux/include/asm-generic/pgtable-nop4d-hack.h

   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 */
  65