pgalloc.h

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/* $Id: pgalloc.h,v 1.3 2000/02/23 00:41:38 ralf Exp $
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994 - 2000 by Ralf Baechle at alii
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 */
#ifndef _ASM_PGALLOC_H
#define _ASM_PGALLOC_H

#include <linux/config.h>

/* TLB flushing:
 *
 *  - flush_tlb_all() flushes all processes TLB entries
 *  - flush_tlb_mm(mm) flushes the specified mm context TLB entries
 *  - flush_tlb_page(mm, vmaddr) flushes a single page
 *  - flush_tlb_range(mm, start, end) flushes a range of pages
 */
extern void flush_tlb_all(void);
extern void flush_tlb_mm(struct mm_struct *mm);
extern void flush_tlb_range(struct mm_struct *mm, unsigned long start,
			       unsigned long end);
extern void flush_tlb_page(struct vm_area_struct *vma, unsigned long page);

extern inline void flush_tlb_pgtables(struct mm_struct *mm,
                                      unsigned long start, unsigned long end)
{
	/* Nothing to do on MIPS.  */
}


/*
 * Allocate and free page tables. The xxx_kernel() versions are
 * used to allocate a kernel page table - this turns on ASN bits
 * if any.
 */

#define pgd_quicklist (current_cpu_data.pgd_quick)
#define pmd_quicklist ((unsigned long *)0)
#define pte_quicklist (current_cpu_data.pte_quick)
#define pgtable_cache_size (current_cpu_data.pgtable_cache_sz)

extern __inline__ pgd_t *get_pgd_slow(void)
{
	pgd_t *ret = (pgd_t *)__get_free_page(GFP_KERNEL), *init;

	if (ret) {
		init = pgd_offset(&init_mm, 0);
		pgd_init((unsigned long)ret);
		memcpy (ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
			(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
	}
	return ret;
}

extern __inline__ pgd_t *get_pgd_fast(void)
{
	unsigned long *ret;

	if((ret = pgd_quicklist) != NULL) {
		pgd_quicklist = (unsigned long *)(*ret);
		ret[0] = ret[1];
		pgtable_cache_size--;
	} else
		ret = (unsigned long *)get_pgd_slow();
	return (pgd_t *)ret;
}

extern __inline__ void free_pgd_fast(pgd_t *pgd)
{
	*(unsigned long *)pgd = (unsigned long) pgd_quicklist;
	pgd_quicklist = (unsigned long *) pgd;
	pgtable_cache_size++;
}

extern __inline__ void free_pgd_slow(pgd_t *pgd)
{
	free_page((unsigned long)pgd);
}

extern pte_t *get_pte_slow(pmd_t *pmd, unsigned long address_preadjusted);
extern pte_t *get_pte_kernel_slow(pmd_t *pmd, unsigned long address_preadjusted);

extern __inline__ pte_t *get_pte_fast(void)
{
	unsigned long *ret;

	if((ret = (unsigned long *)pte_quicklist) != NULL) {
		pte_quicklist = (unsigned long *)(*ret);
		ret[0] = ret[1];
		pgtable_cache_size--;
	}
	return (pte_t *)ret;
}

extern __inline__ void free_pte_fast(pte_t *pte)
{
	*(unsigned long *)pte = (unsigned long) pte_quicklist;
	pte_quicklist = (unsigned long *) pte;
	pgtable_cache_size++;
}

extern __inline__ void free_pte_slow(pte_t *pte)
{
	free_page((unsigned long)pte);
}

/* We don't use pmd cache, so these are dummy routines */
extern __inline__ pmd_t *get_pmd_fast(void)
{
	return (pmd_t *)0;
}

extern __inline__ void free_pmd_fast(pmd_t *pmd)
{
}

extern __inline__ void free_pmd_slow(pmd_t *pmd)
{
}

extern void __bad_pte(pmd_t *pmd);
extern void __bad_pte_kernel(pmd_t *pmd);

#define pte_free_kernel(pte)    free_pte_fast(pte)
#define pte_free(pte)           free_pte_fast(pte)
#define pgd_free(pgd)           free_pgd_fast(pgd)
#define pgd_alloc()             get_pgd_fast()

extern inline pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)
{
	address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);

	if (pmd_none(*pmd)) {
		pte_t *page = get_pte_fast();
		if (page) {
			pmd_val(*pmd) = (unsigned long)page;
			return page + address;
		}
		return get_pte_kernel_slow(pmd, address);
	}
	if (pmd_bad(*pmd)) {
		__bad_pte_kernel(pmd);
		return NULL;
	}
	return (pte_t *) pmd_page(*pmd) + address;
}

extern inline pte_t * pte_alloc(pmd_t * pmd, unsigned long address)
{
	address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);

	if (pmd_none(*pmd)) {
		pte_t *page = get_pte_fast();
		if (page) {
			pmd_val(*pmd) = (unsigned long)page;
			return page + address;
		}
		return get_pte_slow(pmd, address);
	}
	if (pmd_bad(*pmd)) {
		__bad_pte(pmd);
		return NULL;
	}
	return (pte_t *) pmd_page(*pmd) + address;
}

/*
 * allocating and freeing a pmd is trivial: the 1-entry pmd is
 * inside the pgd, so has no extra memory associated with it.
 */
extern inline void pmd_free(pmd_t * pmd)
{
}

extern inline pmd_t * pmd_alloc(pgd_t * pgd, unsigned long address)
{
	return (pmd_t *) pgd;
}

#define pmd_free_kernel		pmd_free
#define pmd_alloc_kernel	pmd_alloc

extern int do_check_pgt_cache(int, int);

extern inline void set_pgdir(unsigned long address, pgd_t entry)
{
	struct task_struct * p;
	pgd_t *pgd;
#ifdef CONFIG_SMP
	int i;
#endif	

	read_lock(&tasklist_lock);
	for_each_task(p) {
		if (!p->mm)
			continue;
		*pgd_offset(p->mm,address) = entry;
	}
	read_unlock(&tasklist_lock);
#ifndef CONFIG_SMP
	for (pgd = (pgd_t *)pgd_quicklist; pgd; pgd = (pgd_t *)*(unsigned long *)pgd)
		pgd[address >> PGDIR_SHIFT] = entry;
#else
	/* To pgd_alloc/pgd_free, one holds master kernel lock and so does our
	   callee, so we can modify pgd caches of other CPUs as well. -jj */
	for (i = 0; i < NR_CPUS; i++)
		for (pgd = (pgd_t *)cpu_data[i].pgd_quick; pgd; pgd = (pgd_t *)*(unsigned long *)pgd)
			pgd[address >> PGDIR_SHIFT] = entry;
#endif
}

#endif /* _ASM_PGALLOC_H */