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asm-generic: introduce <asm-generic/pgtable-nop4d.h>

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Like with pgtable-nopud.h for 4-level paging, this new header is base
for converting an architectures to properly folded p4d_t level.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2017-03-09 17:24:06 +03:00 • committed by Linus Torvalds
parent 9849a5697d
commit 048456dcf2
3 changed files with 89 additions and 24 deletions
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56
include/asm-generic/pgtable-nop4d.h Normal file
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#ifndef _PGTABLE_NOP4D_H
#define _PGTABLE_NOP4D_H
#ifndef __ASSEMBLY__
#define __PAGETABLE_P4D_FOLDED
typedef struct { pgd_t pgd; } p4d_t;
#define P4D_SHIFT PGDIR_SHIFT
#define PTRS_PER_P4D 1
#define P4D_SIZE (1UL << P4D_SHIFT)
#define P4D_MASK (~(P4D_SIZE-1))
/*
* The "pgd_xxx()" functions here are trivial for a folded two-level
* setup: the p4d is never bad, and a p4d always exists (as it's folded
* into the pgd entry)
*/
static inline int pgd_none(pgd_t pgd) { return 0; }
static inline int pgd_bad(pgd_t pgd) { return 0; }
static inline int pgd_present(pgd_t pgd) { return 1; }
static inline void pgd_clear(pgd_t *pgd) { }
#define p4d_ERROR(p4d) (pgd_ERROR((p4d).pgd))
#define pgd_populate(mm, pgd, p4d) do { } while (0)
/*
* (p4ds are folded into pgds so this doesn't get actually called,
* but the define is needed for a generic inline function.)
*/
#define set_pgd(pgdptr, pgdval) set_p4d((p4d_t *)(pgdptr), (p4d_t) { pgdval })
static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
{
return (p4d_t *)pgd;
}
#define p4d_val(x) (pgd_val((x).pgd))
#define __p4d(x) ((p4d_t) { __pgd(x) })
#define pgd_page(pgd) (p4d_page((p4d_t){ pgd }))
#define pgd_page_vaddr(pgd) (p4d_page_vaddr((p4d_t){ pgd }))
/*
* allocating and freeing a p4d is trivial: the 1-entry p4d is
* inside the pgd, so has no extra memory associated with it.
*/
#define p4d_alloc_one(mm, address) NULL
#define p4d_free(mm, x) do { } while (0)
#define __p4d_free_tlb(tlb, x, a) do { } while (0)
#undef p4d_addr_end
#define p4d_addr_end(addr, end) (end)
#endif /* __ASSEMBLY__ */
#endif /* _PGTABLE_NOP4D_H */