1 /*
2  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
3  * Copyright (C) 2008-2009 PetaLogix
4  * Copyright (C) 2006 Atmark Techno, Inc.
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License. See the file "COPYING" in the main directory of this archive
8  * for more details.
9  */
10 
11 #ifndef _ASM_MICROBLAZE_PGALLOC_H
12 #define _ASM_MICROBLAZE_PGALLOC_H
13 
14 #ifdef CONFIG_MMU
15 
16 #include <linux/kernel.h>	/* For min/max macros */
17 #include <linux/highmem.h>
18 #include <asm/setup.h>
19 #include <asm/io.h>
20 #include <asm/page.h>
21 #include <asm/cache.h>
22 #include <asm/pgtable.h>
23 
24 #define PGDIR_ORDER	0
25 
26 /*
27  * This is handled very differently on MicroBlaze since out page tables
28  * are all 0's and I want to be able to use these zero'd pages elsewhere
29  * as well - it gives us quite a speedup.
30  * -- Cort
31  */
32 extern struct pgtable_cache_struct {
33 	unsigned long *pgd_cache;
34 	unsigned long *pte_cache;
35 	unsigned long pgtable_cache_sz;
36 } quicklists;
37 
38 #define pgd_quicklist		(quicklists.pgd_cache)
39 #define pmd_quicklist		((unsigned long *)0)
40 #define pte_quicklist		(quicklists.pte_cache)
41 #define pgtable_cache_size	(quicklists.pgtable_cache_sz)
42 
43 extern unsigned long *zero_cache; /* head linked list of pre-zero'd pages */
44 extern atomic_t zero_sz; /* # currently pre-zero'd pages */
45 extern atomic_t zeropage_hits; /* # zero'd pages request that we've done */
46 extern atomic_t zeropage_calls; /* # zero'd pages request that've been made */
47 extern atomic_t zerototal; /* # pages zero'd over time */
48 
49 #define zero_quicklist		(zero_cache)
50 #define zero_cache_sz	 	(zero_sz)
51 #define zero_cache_calls	(zeropage_calls)
52 #define zero_cache_hits		(zeropage_hits)
53 #define zero_cache_total	(zerototal)
54 
55 /*
56  * return a pre-zero'd page from the list,
57  * return NULL if none available -- Cort
58  */
59 extern unsigned long get_zero_page_fast(void);
60 
61 extern void __bad_pte(pmd_t *pmd);
62 
63 static inline pgd_t *get_pgd_slow(void)
64 {
65 	pgd_t *ret;
66 
67 	ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGDIR_ORDER);
68 	if (ret != NULL)
69 		clear_page(ret);
70 	return ret;
71 }
72 
73 static inline pgd_t *get_pgd_fast(void)
74 {
75 	unsigned long *ret;
76 
77 	ret = pgd_quicklist;
78 	if (ret != NULL) {
79 		pgd_quicklist = (unsigned long *)(*ret);
80 		ret[0] = 0;
81 		pgtable_cache_size--;
82 	} else
83 		ret = (unsigned long *)get_pgd_slow();
84 	return (pgd_t *)ret;
85 }
86 
87 static inline void free_pgd_fast(pgd_t *pgd)
88 {
89 	*(unsigned long **)pgd = pgd_quicklist;
90 	pgd_quicklist = (unsigned long *) pgd;
91 	pgtable_cache_size++;
92 }
93 
94 static inline void free_pgd_slow(pgd_t *pgd)
95 {
96 	free_page((unsigned long)pgd);
97 }
98 
99 #define pgd_free(mm, pgd)        free_pgd_fast(pgd)
100 #define pgd_alloc(mm)		get_pgd_fast()
101 
102 #define pmd_pgtable(pmd)	pmd_page(pmd)
103 
104 /*
105  * We don't have any real pmd's, and this code never triggers because
106  * the pgd will always be present..
107  */
108 #define pmd_alloc_one_fast(mm, address)	({ BUG(); ((pmd_t *)1); })
109 #define pmd_alloc_one(mm, address)	({ BUG(); ((pmd_t *)2); })
110 
111 extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr);
112 
113 static inline struct page *pte_alloc_one(struct mm_struct *mm,
114 		unsigned long address)
115 {
116 	struct page *ptepage;
117 
118 #ifdef CONFIG_HIGHPTE
119 	int flags = GFP_KERNEL | __GFP_HIGHMEM;
120 #else
121 	int flags = GFP_KERNEL;
122 #endif
123 
124 	ptepage = alloc_pages(flags, 0);
125 	if (!ptepage)
126 		return NULL;
127 	clear_highpage(ptepage);
128 	if (!pgtable_page_ctor(ptepage)) {
129 		__free_page(ptepage);
130 		return NULL;
131 	}
132 	return ptepage;
133 }
134 
135 static inline pte_t *pte_alloc_one_fast(struct mm_struct *mm,
136 		unsigned long address)
137 {
138 	unsigned long *ret;
139 
140 	ret = pte_quicklist;
141 	if (ret != NULL) {
142 		pte_quicklist = (unsigned long *)(*ret);
143 		ret[0] = 0;
144 		pgtable_cache_size--;
145 	}
146 	return (pte_t *)ret;
147 }
148 
149 static inline void pte_free_fast(pte_t *pte)
150 {
151 	*(unsigned long **)pte = pte_quicklist;
152 	pte_quicklist = (unsigned long *) pte;
153 	pgtable_cache_size++;
154 }
155 
156 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
157 {
158 	free_page((unsigned long)pte);
159 }
160 
161 static inline void pte_free_slow(struct page *ptepage)
162 {
163 	__free_page(ptepage);
164 }
165 
166 static inline void pte_free(struct mm_struct *mm, struct page *ptepage)
167 {
168 	pgtable_page_dtor(ptepage);
169 	__free_page(ptepage);
170 }
171 
172 #define __pte_free_tlb(tlb, pte, addr)	pte_free((tlb)->mm, (pte))
173 
174 #define pmd_populate(mm, pmd, pte) \
175 			(pmd_val(*(pmd)) = (unsigned long)page_address(pte))
176 
177 #define pmd_populate_kernel(mm, pmd, pte) \
178 		(pmd_val(*(pmd)) = (unsigned long) (pte))
179 
180 /*
181  * We don't have any real pmd's, and this code never triggers because
182  * the pgd will always be present..
183  */
184 #define pmd_alloc_one(mm, address)	({ BUG(); ((pmd_t *)2); })
185 #define pmd_free(mm, x)			do { } while (0)
186 #define __pmd_free_tlb(tlb, x, addr)	pmd_free((tlb)->mm, x)
187 #define pgd_populate(mm, pmd, pte)	BUG()
188 
189 extern int do_check_pgt_cache(int, int);
190 
191 #endif /* CONFIG_MMU */
192 
193 #define check_pgt_cache()		do { } while (0)
194 
195 #endif /* _ASM_MICROBLAZE_PGALLOC_H */
196