include/asm-x86/pgalloc.h

#ifndef _ASM_X86_PGALLOC_H
#define _ASM_X86_PGALLOC_H

#include <linux/threads.h>
#include <linux/mm.h>		/* for struct page */
#include <linux/pagemap.h>

#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#define paravirt_alloc_pt(mm, pfn) do { } while (0)
#define paravirt_alloc_pd(mm, pfn) do { } while (0)
#define paravirt_alloc_pd_clone(pfn, clonepfn, start, count) do { } while (0)
#define paravirt_release_pt(pfn) do { } while (0)
#define paravirt_release_pd(pfn) do { } while (0)
#endif

/*
 * Allocate and free page tables.
 */
extern pgd_t *pgd_alloc(struct mm_struct *);
extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);

extern pte_t *pte_alloc_one_kernel(struct mm_struct *, unsigned long);
extern pgtable_t pte_alloc_one(struct mm_struct *, unsigned long);

/* Should really implement gc for free page table pages. This could be
   done with a reference count in struct page. */

static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
	BUG_ON((unsigned long)pte & (PAGE_SIZE-1));
	free_page((unsigned long)pte);
}

static inline void pte_free(struct mm_struct *mm, struct page *pte)
{
	__free_page(pte);
}

extern void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte);

static inline void pmd_populate_kernel(struct mm_struct *mm,
				       pmd_t *pmd, pte_t *pte)
{
	paravirt_alloc_pt(mm, __pa(pte) >> PAGE_SHIFT);
	set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
}

static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
				struct page *pte)
{
	unsigned long pfn = page_to_pfn(pte);

	paravirt_alloc_pt(mm, pfn);
	set_pmd(pmd, __pmd(((pteval_t)pfn << PAGE_SHIFT) | _PAGE_TABLE));
}

#define pmd_pgtable(pmd) pmd_page(pmd)

#if PAGETABLE_LEVELS > 2
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
{
	return (pmd_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
}

static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
	BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
	free_page((unsigned long)pmd);
}

extern void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd);
#endif	/* PAGETABLE_LEVELS > 2 */

#ifdef CONFIG_X86_32
# include "pgalloc_32.h"
#else
# include "pgalloc_64.h"
#endif

#endif	/* _ASM_X86_PGALLOC_H */