/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* vineetg: June 2011
* -"/proc/meminfo | grep PageTables" kept on increasing
* Recently added pgtable dtor was not getting called.
*
* vineetg: May 2011
* -Variable pg-sz means that Page Tables could be variable sized themselves
* So calculate it based on addr traversal split [pgd-bits:pte-bits:xxx]
* -Page Table size capped to max 1 to save memory - hence verified.
* -Since these deal with constants, gcc compile-time optimizes them.
*
* vineetg: Nov 2010
* -Added pgtable ctor/dtor used for pgtable mem accounting
*
* vineetg: April 2010
* -Switched pgtable_t from being struct page * to unsigned long
* =Needed so that Page Table allocator (pte_alloc_one) is not forced to
* to deal with struct page. Thay way in future we can make it allocate
* multiple PG Tbls in one Page Frame
* =sweet side effect is avoiding calls to ugly page_address( ) from the
* pg-tlb allocator sub-sys (pte_alloc_one, ptr_free, pmd_populate
*
* Amit Bhor, Sameer Dhavale: Codito Technologies 2004
*/

#ifndef _ASM_ARC_PGALLOC_H
#define _ASM_ARC_PGALLOC_H

#include <linux/mm.h>
#include <linux/log2.h>

static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
{
pmd_set(pmd, pte);
}

static inline void
pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep)
{
pmd_set(pmd, (pte_t *) ptep);
}

static inline int __get_order_pgd(void)
{
return get_order(PTRS_PER_PGD * 4);
}

static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
int num, num2;
pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd());

if (ret) {
num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE;
memzero(ret, num * sizeof(pgd_t));

num2 = VMALLOC_SIZE / PGDIR_SIZE;
memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t));

memzero(ret + num + num2,
(PTRS_PER_PGD - num - num2) * sizeof(pgd_t));

}
return ret;
}

static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
free_pages((unsigned long)pgd, __get_order_pgd());
}


/*
* With software-only page-tables, addr-split for traversal is tweakable and
* that directly governs how big tables would be at each level.
* Further, the MMU page size is configurable.
* Thus we need to programatically assert the size constraint
* All of this is const math, allowing gcc to do constant folding/propagation.
*/

static inline int __get_order_pte(void)
{
return get_order(PTRS_PER_PTE * 4);
}

static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
pte_t *pte;

pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO,
__get_order_pte());

return pte;
}

static inline pgtable_t
pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
pgtable_t pte_pg;
struct page *page;

pte_pg = __get_free_pages(GFP_KERNEL | __GFP_REPEAT, __get_order_pte());
if (!pte_pg)
return 0;
memzero((void *)pte_pg, PTRS_PER_PTE * 4);
page = virt_to_page(pte_pg);
if (!pgtable_page_ctor(page)) {
__free_page(page);
return 0;
}

return pte_pg;
}

static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */
}

static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
{
pgtable_page_dtor(virt_to_page(ptep));
free_pages(ptep, __get_order_pte());
}

#define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte)

#define check_pgt_cache() do { } while (0)
#define pmd_pgtable(pmd) pmd_page_vaddr(pmd)

#endif /* _ASM_ARC_PGALLOC_H */