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c65e774fb3
For boot-time switching between 4- and 5-level paging we need to be able to fold p4d page table level at runtime. It requires variable PGDIR_SHIFT and PTRS_PER_P4D. The change doesn't affect the kernel image size much: text data bss dec hex filename 8628091 4734304 1368064 14730459 e0c4db vmlinux.before 8628393 4734340 1368064 14730797 e0c62d vmlinux.after Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180214111656.88514-7-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _PGTABLE_NOP4D_H
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#define _PGTABLE_NOP4D_H
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#ifndef __ASSEMBLY__
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#define __PAGETABLE_P4D_FOLDED
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typedef struct { pgd_t pgd; } p4d_t;
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#define P4D_SHIFT PGDIR_SHIFT
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#define MAX_PTRS_PER_P4D 1
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#define PTRS_PER_P4D 1
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#define P4D_SIZE (1UL << P4D_SHIFT)
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#define P4D_MASK (~(P4D_SIZE-1))
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/*
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* The "pgd_xxx()" functions here are trivial for a folded two-level
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* setup: the p4d is never bad, and a p4d always exists (as it's folded
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* into the pgd entry)
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*/
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static inline int pgd_none(pgd_t pgd) { return 0; }
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static inline int pgd_bad(pgd_t pgd) { return 0; }
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static inline int pgd_present(pgd_t pgd) { return 1; }
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static inline void pgd_clear(pgd_t *pgd) { }
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#define p4d_ERROR(p4d) (pgd_ERROR((p4d).pgd))
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#define pgd_populate(mm, pgd, p4d) do { } while (0)
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/*
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* (p4ds are folded into pgds so this doesn't get actually called,
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* but the define is needed for a generic inline function.)
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*/
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#define set_pgd(pgdptr, pgdval) set_p4d((p4d_t *)(pgdptr), (p4d_t) { pgdval })
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static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
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{
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return (p4d_t *)pgd;
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}
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#define p4d_val(x) (pgd_val((x).pgd))
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#define __p4d(x) ((p4d_t) { __pgd(x) })
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#define pgd_page(pgd) (p4d_page((p4d_t){ pgd }))
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#define pgd_page_vaddr(pgd) (p4d_page_vaddr((p4d_t){ pgd }))
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/*
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* allocating and freeing a p4d is trivial: the 1-entry p4d is
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* inside the pgd, so has no extra memory associated with it.
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*/
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#define p4d_alloc_one(mm, address) NULL
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#define p4d_free(mm, x) do { } while (0)
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#define __p4d_free_tlb(tlb, x, a) do { } while (0)
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#undef p4d_addr_end
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#define p4d_addr_end(addr, end) (end)
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#endif /* __ASSEMBLY__ */
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#endif /* _PGTABLE_NOP4D_H */
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