This source file includes following definitions.
- set_pgdir
- free_area_pages
- alloc_area_pages
- do_area
- vfree
- vmalloc
- vread
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7 #include <asm/system.h>
8 #include <linux/config.h>
9
10 #include <linux/signal.h>
11 #include <linux/sched.h>
12 #include <linux/head.h>
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/types.h>
16 #include <linux/malloc.h>
17 #include <asm/segment.h>
18
19 struct vm_struct {
20 unsigned long flags;
21 void * addr;
22 unsigned long size;
23 struct vm_struct * next;
24 };
25
26 static struct vm_struct * vmlist = NULL;
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28
29
30
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32
33
34
35 #define VMALLOC_OFFSET (8*1024*1024)
36
37 static inline void set_pgdir(unsigned long dindex, unsigned long value)
38 {
39 struct task_struct * p;
40
41 p = &init_task;
42 do {
43 ((unsigned long *) p->tss.cr3)[dindex] = value;
44 p = p->next_task;
45 } while (p != &init_task);
46 }
47
48 static int free_area_pages(unsigned long dindex, unsigned long index, unsigned long nr)
49 {
50 unsigned long page, *pte;
51
52 if (!(PAGE_PRESENT & (page = swapper_pg_dir[dindex])))
53 return 0;
54 page &= PAGE_MASK;
55 pte = index + (unsigned long *) page;
56 for ( ; nr > 0 ; nr--, pte++) {
57 unsigned long pg = *pte;
58 *pte = 0;
59 if (!(pg & PAGE_PRESENT))
60 continue;
61 free_page(pg);
62 }
63 pte = (unsigned long *) page;
64 for (nr = 0 ; nr < 1024 ; nr++, pte++)
65 if (*pte)
66 return 0;
67 set_pgdir(dindex,0);
68 mem_map[MAP_NR(page)] &= ~MAP_PAGE_RESERVED;
69 free_page(page);
70 return 0;
71 }
72
73 static int alloc_area_pages(unsigned long dindex, unsigned long index, unsigned long nr)
74 {
75 unsigned long page, *pte;
76
77 page = swapper_pg_dir[dindex];
78 if (!page) {
79 page = get_free_page(GFP_KERNEL);
80 if (!page)
81 return -ENOMEM;
82 if (swapper_pg_dir[dindex]) {
83 free_page(page);
84 page = swapper_pg_dir[dindex];
85 } else {
86 mem_map[MAP_NR(page)] |= MAP_PAGE_RESERVED;
87 set_pgdir(dindex, page | PAGE_SHARED);
88 }
89 }
90 page &= PAGE_MASK;
91 pte = index + (unsigned long *) page;
92 *pte = PAGE_SHARED;
93 for ( ; nr > 0 ; nr--, pte++) {
94 unsigned long pg = get_free_page(GFP_KERNEL);
95
96 if (!pg)
97 return -ENOMEM;
98 *pte = pg | PAGE_SHARED;
99 }
100 return 0;
101 }
102
103 static int do_area(void * addr, unsigned long size,
104 int (*area_fn)(unsigned long,unsigned long,unsigned long))
105 {
106 unsigned long nr, dindex, index;
107
108 nr = size >> PAGE_SHIFT;
109 dindex = (TASK_SIZE + (unsigned long) addr) >> 22;
110 index = (((unsigned long) addr) >> PAGE_SHIFT) & (PTRS_PER_PAGE-1);
111 while (nr > 0) {
112 unsigned long i = PTRS_PER_PAGE - index;
113
114 if (i > nr)
115 i = nr;
116 if (area_fn(dindex, index, i))
117 return -1;
118 nr -= i;
119 index = 0;
120 dindex++;
121 }
122 return 0;
123 }
124
125 void vfree(void * addr)
126 {
127 struct vm_struct **p, *tmp;
128
129 if (!addr)
130 return;
131 if ((PAGE_SIZE-1) & (unsigned long) addr) {
132 printk("Trying to vfree() bad address (%p)\n", addr);
133 return;
134 }
135 for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
136 if (tmp->addr == addr) {
137 *p = tmp->next;
138 do_area(tmp->addr, tmp->size, free_area_pages);
139 kfree(tmp);
140 return;
141 }
142 }
143 printk("Trying to vfree() nonexistent vm area (%p)\n", addr);
144 }
145
146 void * vmalloc(unsigned long size)
147 {
148 void * addr;
149 struct vm_struct **p, *tmp, *area;
150
151 size = PAGE_ALIGN(size);
152 if (!size || size > high_memory)
153 return NULL;
154 area = (struct vm_struct *) kmalloc(sizeof(*area), GFP_KERNEL);
155 if (!area)
156 return NULL;
157 addr = (void *) ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1));
158 area->size = size + PAGE_SIZE;
159 area->next = NULL;
160 for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {
161 if (size + (unsigned long) addr < (unsigned long) tmp->addr)
162 break;
163 addr = (void *) (tmp->size + (unsigned long) tmp->addr);
164 }
165 area->addr = addr;
166 area->next = *p;
167 *p = area;
168 if (do_area(addr, size, alloc_area_pages)) {
169 vfree(addr);
170 return NULL;
171 }
172 return addr;
173 }
174
175 int vread(char *buf, char *addr, int count)
176 {
177 struct vm_struct **p, *tmp;
178 char *vaddr, *buf_start = buf;
179 int n;
180
181 for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {
182 vaddr = (char *) tmp->addr;
183 while (addr < vaddr) {
184 if (count == 0)
185 goto finished;
186 put_fs_byte('\0', buf++), addr++, count--;
187 }
188 n = tmp->size - PAGE_SIZE;
189 if (addr > vaddr)
190 n -= addr - vaddr;
191 while (--n >= 0) {
192 if (count == 0)
193 goto finished;
194 put_fs_byte(*addr++, buf++), count--;
195 }
196 }
197 finished:
198 return buf - buf_start;
199 }