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 
23 #define PGDIR_ORDER	0
24 
25 /*
26  * This is handled very differently on MicroBlaze since out page tables
27  * are all 0's and I want to be able to use these zero'd pages elsewhere
28  * as well - it gives us quite a speedup.
29  * -- Cort
30  */
31 extern struct pgtable_cache_struct {
32 	unsigned long *pgd_cache;
33 	unsigned long *pte_cache;
34 	unsigned long pgtable_cache_sz;
35 } quicklists;
36 
37 #define pgd_quicklist		(quicklists.pgd_cache)
38 #define pmd_quicklist		((unsigned long *)0)
39 #define pte_quicklist		(quicklists.pte_cache)
40 #define pgtable_cache_size	(quicklists.pgtable_cache_sz)
41 
42 extern unsigned long *zero_cache; /* head linked list of pre-zero'd pages */
43 extern atomic_t zero_sz; /* # currently pre-zero'd pages */
44 extern atomic_t zeropage_hits; /* # zero'd pages request that we've done */
45 extern atomic_t zeropage_calls; /* # zero'd pages request that've been made */
46 extern atomic_t zerototal; /* # pages zero'd over time */
47 
48 #define zero_quicklist		(zero_cache)
49 #define zero_cache_sz	 	(zero_sz)
50 #define zero_cache_calls	(zeropage_calls)
51 #define zero_cache_hits		(zeropage_hits)
52 #define zero_cache_total	(zerototal)
53 
54 /*
55  * return a pre-zero'd page from the list,
56  * return NULL if none available -- Cort
57  */
58 extern unsigned long get_zero_page_fast(void);
59 
60 extern void __bad_pte(pmd_t *pmd);
61 
62 extern inline pgd_t *get_pgd_slow(void)
63 {
64 	pgd_t *ret;
65 
66 	ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGDIR_ORDER);
67 	if (ret != NULL)
68 		clear_page(ret);
69 	return ret;
70 }
71 
72 extern inline pgd_t *get_pgd_fast(void)
73 {
74 	unsigned long *ret;
75 
76 	ret = pgd_quicklist;
77 	if (ret != NULL) {
78 		pgd_quicklist = (unsigned long *)(*ret);
79 		ret[0] = 0;
80 		pgtable_cache_size--;
81 	} else
82 		ret = (unsigned long *)get_pgd_slow();
83 	return (pgd_t *)ret;
84 }
85 
86 extern inline void free_pgd_fast(pgd_t *pgd)
87 {
88 	*(unsigned long **)pgd = pgd_quicklist;
89 	pgd_quicklist = (unsigned long *) pgd;
90 	pgtable_cache_size++;
91 }
92 
93 extern inline void free_pgd_slow(pgd_t *pgd)
94 {
95 	free_page((unsigned long)pgd);
96 }
97 
98 #define pgd_free(mm, pgd)        free_pgd_fast(pgd)
99 #define pgd_alloc(mm)		get_pgd_fast()
100 
101 #define pmd_pgtable(pmd)	pmd_page(pmd)
102 
103 /*
104  * We don't have any real pmd's, and this code never triggers because
105  * the pgd will always be present..
106  */
107 #define pmd_alloc_one_fast(mm, address)	({ BUG(); ((pmd_t *)1); })
108 #define pmd_alloc_one(mm, address)	({ BUG(); ((pmd_t *)2); })
109 
110 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
111 		unsigned long address)
112 {
113 	pte_t *pte;
114 	extern int mem_init_done;
115 	extern void *early_get_page(void);
116 	if (mem_init_done) {
117 		pte = (pte_t *)__get_free_page(GFP_KERNEL |
118 					__GFP_REPEAT | __GFP_ZERO);
119 	} else {
120 		pte = (pte_t *)early_get_page();
121 		if (pte)
122 			clear_page(pte);
123 	}
124 	return pte;
125 }
126 
127 static inline struct page *pte_alloc_one(struct mm_struct *mm,
128 		unsigned long address)
129 {
130 	struct page *ptepage;
131 
132 #ifdef CONFIG_HIGHPTE
133 	int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
134 #else
135 	int flags = GFP_KERNEL | __GFP_REPEAT;
136 #endif
137 
138 	ptepage = alloc_pages(flags, 0);
139 	if (ptepage)
140 		clear_highpage(ptepage);
141 	return ptepage;
142 }
143 
144 static inline pte_t *pte_alloc_one_fast(struct mm_struct *mm,
145 		unsigned long address)
146 {
147 	unsigned long *ret;
148 
149 	ret = pte_quicklist;
150 	if (ret != NULL) {
151 		pte_quicklist = (unsigned long *)(*ret);
152 		ret[0] = 0;
153 		pgtable_cache_size--;
154 	}
155 	return (pte_t *)ret;
156 }
157 
158 extern inline void pte_free_fast(pte_t *pte)
159 {
160 	*(unsigned long **)pte = pte_quicklist;
161 	pte_quicklist = (unsigned long *) pte;
162 	pgtable_cache_size++;
163 }
164 
165 extern inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
166 {
167 	free_page((unsigned long)pte);
168 }
169 
170 extern inline void pte_free_slow(struct page *ptepage)
171 {
172 	__free_page(ptepage);
173 }
174 
175 extern inline void pte_free(struct mm_struct *mm, struct page *ptepage)
176 {
177 	__free_page(ptepage);
178 }
179 
180 #define __pte_free_tlb(tlb, pte, addr)	pte_free((tlb)->mm, (pte))
181 
182 #define pmd_populate(mm, pmd, pte)	(pmd_val(*(pmd)) = page_address(pte))
183 
184 #define pmd_populate_kernel(mm, pmd, pte) \
185 		(pmd_val(*(pmd)) = (unsigned long) (pte))
186 
187 /*
188  * We don't have any real pmd's, and this code never triggers because
189  * the pgd will always be present..
190  */
191 #define pmd_alloc_one(mm, address)	({ BUG(); ((pmd_t *)2); })
192 #define pmd_free(mm, x)			do { } while (0)
193 #define __pmd_free_tlb(tlb, x, addr)	pmd_free((tlb)->mm, x)
194 #define pgd_populate(mm, pmd, pte)	BUG()
195 
196 extern int do_check_pgt_cache(int, int);
197 
198 #endif /* CONFIG_MMU */
199 
200 #define check_pgt_cache()		do { } while (0)
201 
202 #endif /* _ASM_MICROBLAZE_PGALLOC_H */
203