1/*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * vineetg: June 2011
9 *  -"/proc/meminfo | grep PageTables" kept on increasing
10 *   Recently added pgtable dtor was not getting called.
11 *
12 * vineetg: May 2011
13 *  -Variable pg-sz means that Page Tables could be variable sized themselves
14 *    So calculate it based on addr traversal split [pgd-bits:pte-bits:xxx]
15 *  -Page Table size capped to max 1 to save memory - hence verified.
16 *  -Since these deal with constants, gcc compile-time optimizes them.
17 *
18 * vineetg: Nov 2010
19 *  -Added pgtable ctor/dtor used for pgtable mem accounting
20 *
21 * vineetg: April 2010
22 *  -Switched pgtable_t from being struct page * to unsigned long
23 *      =Needed so that Page Table allocator (pte_alloc_one) is not forced to
24 *       to deal with struct page. Thay way in future we can make it allocate
25 *       multiple PG Tbls in one Page Frame
26 *      =sweet side effect is avoiding calls to ugly page_address( ) from the
27 *       pg-tlb allocator sub-sys (pte_alloc_one, ptr_free, pmd_populate
28 *
29 *  Amit Bhor, Sameer Dhavale: Codito Technologies 2004
30 */
31
32#ifndef _ASM_ARC_PGALLOC_H
33#define _ASM_ARC_PGALLOC_H
34
35#include <linux/mm.h>
36#include <linux/log2.h>
37
38static inline void
39pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
40{
41	pmd_set(pmd, pte);
42}
43
44static inline void
45pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep)
46{
47	pmd_set(pmd, (pte_t *) ptep);
48}
49
50static inline int __get_order_pgd(void)
51{
52	return get_order(PTRS_PER_PGD * 4);
53}
54
55static inline pgd_t *pgd_alloc(struct mm_struct *mm)
56{
57	int num, num2;
58	pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd());
59
60	if (ret) {
61		num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE;
62		memzero(ret, num * sizeof(pgd_t));
63
64		num2 = VMALLOC_SIZE / PGDIR_SIZE;
65		memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t));
66
67		memzero(ret + num + num2,
68			       (PTRS_PER_PGD - num - num2) * sizeof(pgd_t));
69
70	}
71	return ret;
72}
73
74static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
75{
76	free_pages((unsigned long)pgd, __get_order_pgd());
77}
78
79
80/*
81 * With software-only page-tables, addr-split for traversal is tweakable and
82 * that directly governs how big tables would be at each level.
83 * Further, the MMU page size is configurable.
84 * Thus we need to programatically assert the size constraint
85 * All of this is const math, allowing gcc to do constant folding/propagation.
86 */
87
88static inline int __get_order_pte(void)
89{
90	return get_order(PTRS_PER_PTE * 4);
91}
92
93static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
94					unsigned long address)
95{
96	pte_t *pte;
97
98	pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO,
99					 __get_order_pte());
100
101	return pte;
102}
103
104static inline pgtable_t
105pte_alloc_one(struct mm_struct *mm, unsigned long address)
106{
107	pgtable_t pte_pg;
108	struct page *page;
109
110	pte_pg = __get_free_pages(GFP_KERNEL | __GFP_REPEAT, __get_order_pte());
111	if (!pte_pg)
112		return 0;
113	memzero((void *)pte_pg, PTRS_PER_PTE * 4);
114	page = virt_to_page(pte_pg);
115	if (!pgtable_page_ctor(page)) {
116		__free_page(page);
117		return 0;
118	}
119
120	return pte_pg;
121}
122
123static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
124{
125	free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */
126}
127
128static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
129{
130	pgtable_page_dtor(virt_to_page(ptep));
131	free_pages(ptep, __get_order_pte());
132}
133
134#define __pte_free_tlb(tlb, pte, addr)  pte_free((tlb)->mm, pte)
135
136#define check_pgt_cache()   do { } while (0)
137#define pmd_pgtable(pmd) pmd_page_vaddr(pmd)
138
139#endif /* _ASM_ARC_PGALLOC_H */
140