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linux-next/include/asm-generic/pgtable-nop4d.h
Daniel Axtens c0f8aa4fa8 mm: define default MAX_PTRS_PER_* in include/pgtable.h
Commit c65e774fb3 ("x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable")
made PTRS_PER_P4D variable on x86 and introduced MAX_PTRS_PER_P4D as a
constant for cases which need a compile-time constant (e.g.  fixed-size
arrays).

powerpc likewise has boot-time selectable MMU features which can cause
other mm "constants" to vary.  For KASAN, we have some static
PTE/PMD/PUD/P4D arrays so we need compile-time maximums for all these
constants.  Extend the MAX_PTRS_PER_ idiom, and place default definitions
in include/pgtable.h.  These define MAX_PTRS_PER_x to be PTRS_PER_x unless
an architecture has defined MAX_PTRS_PER_x in its arch headers.

Clean up pgtable-nop4d.h and s390's MAX_PTRS_PER_P4D definitions while
we're at it: both can just pick up the default now.

Link: https://lkml.kernel.org/r/20210624034050.511391-4-dja@axtens.net
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29 10:53:53 -07:00

59 lines
1.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _PGTABLE_NOP4D_H
#define _PGTABLE_NOP4D_H
#ifndef __ASSEMBLY__
#define __PAGETABLE_P4D_FOLDED 1
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)
#define pgd_populate_safe(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 */