pgalloc.h

是关于linux2.5.1的完全源码

/*
 *  linux/include/asm-arm/proc-armv/pgalloc.h
 *
 *  Copyright (C) 2001-2002 Russell King
 *
 * Page table allocation/freeing primitives for 32-bit ARM processors.
 */
#include "pgtable.h"

/*
 * Allocate one PTE table.
 *
 * This actually allocates two hardware PTE tables, but we wrap this up
 * into one table thus:
 *
 *  +------------+
 *  |  h/w pt 0  |
 *  +------------+
 *  |  h/w pt 1  |
 *  +------------+
 *  | Linux pt 0 |
 *  +------------+
 *  | Linux pt 1 |
 *  +------------+
 */
static inline pte_t *
pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
{
	int count = 0;
	pte_t *pte;

	do {
		pte = (pte_t *)__get_free_page(GFP_KERNEL);
		if (!pte) {
			current->state = TASK_UNINTERRUPTIBLE;
			schedule_timeout(HZ);
		}
	} while (!pte && (count++ < 10));

	if (pte) {
		clear_page(pte);
		clean_dcache_area(pte, sizeof(pte_t) * PTRS_PER_PTE);
		pte += PTRS_PER_PTE;
	}

	return pte;
}

static inline struct page *
pte_alloc_one(struct mm_struct *mm, unsigned long addr)
{
	struct page *pte;
	int count = 0;

	do {
		pte = alloc_pages(GFP_KERNEL, 0);
		if (!pte) {
			current->state = TASK_UNINTERRUPTIBLE;
			schedule_timeout(HZ);
		}
	} while (!pte && (count++ < 10));

	if (pte) {
		void *page = page_address(pte);
		clear_page(page);
		clean_dcache_area(page, sizeof(pte_t) * PTRS_PER_PTE);
	}

	return pte;
}

/*
 * Free one PTE table.
 */
static inline void pte_free_kernel(pte_t *pte)
{
	if (pte) {
		pte -= PTRS_PER_PTE;
		free_page((unsigned long)pte);
	}
}

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

/*
 * Populate the pmdp entry with a pointer to the pte.  This pmd is part
 * of the mm address space.
 *
 * Ensure that we always set both PMD entries.
 */
static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
{
	unsigned long pte_ptr = (unsigned long)ptep;
	pmd_t pmd;

	BUG_ON(mm != &init_mm);

	/*
	 * The pmd must be loaded with the physical
	 * address of the PTE table
	 */
	pte_ptr -= PTRS_PER_PTE * sizeof(void *);
	pmd_val(pmd) = __pa(pte_ptr) | _PAGE_KERNEL_TABLE;
	set_pmd(pmdp, pmd);
	pmd_val(pmd) += 256 * sizeof(pte_t);
	set_pmd(pmdp + 1, pmd);
}

static inline void
pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *ptep)
{
	pmd_t pmd;

	BUG_ON(mm == &init_mm);

	pmd_val(pmd) = __pa(page_address(ptep)) | _PAGE_USER_TABLE;
	set_pmd(pmdp, pmd);
	pmd_val(pmd) += 256 * sizeof(pte_t);
	set_pmd(pmdp + 1, pmd);
}