From 30ec842660bd0d056d4a7028ac5bd4a82b113d4f Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 9 Mar 2017 17:24:04 +0300 Subject: [PATCH] asm-generic: introduce __ARCH_USE_5LEVEL_HACK We are going to introduce to provide abstraction for properly (in opposite to 5level-fixup.h hack) folded p4d level. The new header will be included from pgtable-nopud.h. If an architecture uses , we cannot use 5level-fixup.h directly to quickly convert the architecture to 5-level paging as it would conflict with pgtable-nop4d.h. With this patch an architecture can define __ARCH_USE_5LEVEL_HACK before inclusion to use 5level-fixup.h. Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds --- include/asm-generic/pgtable-nop4d-hack.h | 62 ++++++++++++++++++++++++ include/asm-generic/pgtable-nopud.h | 5 ++ 2 files changed, 67 insertions(+) create mode 100644 include/asm-generic/pgtable-nop4d-hack.h diff --git a/include/asm-generic/pgtable-nop4d-hack.h b/include/asm-generic/pgtable-nop4d-hack.h new file mode 100644 index 000000000000..752fb7511750 --- /dev/null +++ b/include/asm-generic/pgtable-nop4d-hack.h @@ -0,0 +1,62 @@ +#ifndef _PGTABLE_NOP4D_HACK_H +#define _PGTABLE_NOP4D_HACK_H + +#ifndef __ASSEMBLY__ +#include + +#define __PAGETABLE_PUD_FOLDED + +/* + * Having the pud type consist of a pgd gets the size right, and allows + * us to conceptually access the pgd entry that this pud is folded into + * without casting. + */ +typedef struct { pgd_t pgd; } pud_t; + +#define PUD_SHIFT PGDIR_SHIFT +#define PTRS_PER_PUD 1 +#define PUD_SIZE (1UL << PUD_SHIFT) +#define PUD_MASK (~(PUD_SIZE-1)) + +/* + * The "pgd_xxx()" functions here are trivial for a folded two-level + * setup: the pud is never bad, and a pud 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 pud_ERROR(pud) (pgd_ERROR((pud).pgd)) + +#define pgd_populate(mm, pgd, pud) do { } while (0) +/* + * (puds 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_pud((pud_t *)(pgdptr), (pud_t) { pgdval }) + +static inline pud_t *pud_offset(pgd_t *pgd, unsigned long address) +{ + return (pud_t *)pgd; +} + +#define pud_val(x) (pgd_val((x).pgd)) +#define __pud(x) ((pud_t) { __pgd(x) }) + +#define pgd_page(pgd) (pud_page((pud_t){ pgd })) +#define pgd_page_vaddr(pgd) (pud_page_vaddr((pud_t){ pgd })) + +/* + * allocating and freeing a pud is trivial: the 1-entry pud is + * inside the pgd, so has no extra memory associated with it. + */ +#define pud_alloc_one(mm, address) NULL +#define pud_free(mm, x) do { } while (0) +#define __pud_free_tlb(tlb, x, a) do { } while (0) + +#undef pud_addr_end +#define pud_addr_end(addr, end) (end) + +#endif /* __ASSEMBLY__ */ +#endif /* _PGTABLE_NOP4D_HACK_H */ diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h index 810431d8351b..5e49430a30a4 100644 --- a/include/asm-generic/pgtable-nopud.h +++ b/include/asm-generic/pgtable-nopud.h @@ -3,6 +3,10 @@ #ifndef __ASSEMBLY__ +#ifdef __ARCH_USE_5LEVEL_HACK +#include +#else + #define __PAGETABLE_PUD_FOLDED /* @@ -58,4 +62,5 @@ static inline pud_t * pud_offset(pgd_t * pgd, unsigned long address) #define pud_addr_end(addr, end) (end) #endif /* __ASSEMBLY__ */ +#endif /* !__ARCH_USE_5LEVEL_HACK */ #endif /* _PGTABLE_NOPUD_H */ -- 2.20.1