source: trunk/minix/kernel/system/do_vm.c@ 15

Last change on this file since 15 was 9, checked in by Mattia Monga, 14 years ago

Minix 3.1.2a
File size: 5.1 KB
Line 
1/* The system call implemented in this file:
2 * m_type: SYS_VM_MAP
3 *
4 * The parameters for this system call are:
5 * m4_l1: Process that requests map (VM_MAP_ENDPT)
6 * m4_l2: Map (TRUE) or unmap (FALSE) (VM_MAP_MAPUNMAP)
7 * m4_l3: Base address (VM_MAP_BASE)
8 * m4_l4: Size (VM_MAP_SIZE)
9 * m4_l5: Memory address (VM_MAP_ADDR)
10 */
11#include "../system.h"
12
13#include <sys/vm.h>
14
15PRIVATE int vm_needs_init= 1;
16PRIVATE u32_t vm_cr3;
17
18FORWARD _PROTOTYPE( void vm_init, (void) );
19FORWARD _PROTOTYPE( void phys_put32, (phys_bytes addr, u32_t value) );
20FORWARD _PROTOTYPE( u32_t phys_get32, (phys_bytes addr) );
21FORWARD _PROTOTYPE( void vm_set_cr3, (u32_t value) );
22FORWARD _PROTOTYPE( void set_cr3, (void) );
23FORWARD _PROTOTYPE( void vm_enable_paging, (void) );
24FORWARD _PROTOTYPE( void map_range, (u32_t base, u32_t size,
25 u32_t offset) );
26
27/*===========================================================================*
28 * do_vm_map *
29 *===========================================================================*/
30PUBLIC int do_vm_map(m_ptr)
31message *m_ptr; /* pointer to request message */
32{
33 int proc_nr, do_map;
34 phys_bytes base, size, offset, p_phys;
35 struct proc *pp;
36
37 /* do_serial_debug= 1; */
38
39 if (vm_needs_init)
40 {
41 vm_needs_init= 0;
42 vm_init();
43 }
44
45 if (m_ptr->VM_MAP_ENDPT == SELF) {
46 proc_nr = who_p;
47 } else {
48 if(!isokendpt(m_ptr->VM_MAP_ENDPT, &proc_nr))
49 return EINVAL;
50 }
51
52 do_map= m_ptr->VM_MAP_MAPUNMAP;
53 base= m_ptr->VM_MAP_BASE;
54 size= m_ptr->VM_MAP_SIZE;
55 offset= m_ptr->VM_MAP_ADDR;
56
57 pp= proc_addr(proc_nr);
58 p_phys= umap_local(pp, D, base, size);
59 if (p_phys == 0)
60 return EFAULT;
61
62 if (do_map)
63 {
64 pp->p_misc_flags |= MF_VM;
65
66 map_range(p_phys, size, offset);
67 }
68 else
69 {
70 map_range(p_phys, size, p_phys);
71 }
72 vm_set_cr3(vm_cr3);
73
74 return OK;
75}
76
77/*===========================================================================*
78 * vm_map_default *
79 *===========================================================================*/
80PUBLIC void vm_map_default(pp)
81struct proc *pp;
82{
83 phys_bytes base_clicks, size_clicks;
84
85 if (vm_needs_init)
86 panic("vm_map_default: VM not initialized?", NO_NUM);
87 pp->p_misc_flags &= ~MF_VM;
88 base_clicks= pp->p_memmap[D].mem_phys;
89 size_clicks= pp->p_memmap[S].mem_phys+pp->p_memmap[S].mem_len -
90 base_clicks;
91 map_range(base_clicks << CLICK_SHIFT, size_clicks << CLICK_SHIFT,
92 base_clicks << CLICK_SHIFT);
93 vm_set_cr3(vm_cr3);
94}
95
96PRIVATE void vm_init(void)
97{
98 int o;
99 phys_bytes p, pt_size;
100 phys_bytes vm_dir_base, vm_pt_base, phys_mem;
101 u32_t entry;
102 unsigned pages;
103
104 if (!vm_size)
105 panic("vm_init: no space for page tables", NO_NUM);
106
107 /* Align page directory */
108 o= (vm_base % PAGE_SIZE);
109 if (o != 0)
110 o= PAGE_SIZE-o;
111 vm_dir_base= vm_base+o;
112
113 /* Page tables start after the page directory */
114 vm_pt_base= vm_dir_base+PAGE_SIZE;
115
116 pt_size= (vm_base+vm_size)-vm_pt_base;
117 pt_size -= (pt_size % PAGE_SIZE);
118
119 /* Compute the number of pages based on vm_mem_high */
120 pages= (vm_mem_high-1)/PAGE_SIZE + 1;
121
122 if (pages * I386_VM_PT_ENT_SIZE > pt_size)
123 panic("vm_init: page table too small", NO_NUM);
124
125 for (p= 0; p*I386_VM_PT_ENT_SIZE < pt_size; p++)
126 {
127 phys_mem= p*PAGE_SIZE;
128 entry= phys_mem | I386_VM_USER | I386_VM_WRITE |
129 I386_VM_PRESENT;
130 if (phys_mem >= vm_mem_high)
131 entry= 0;
132 phys_put32(vm_pt_base + p*I386_VM_PT_ENT_SIZE, entry);
133 }
134
135 for (p= 0; p < I386_VM_DIR_ENTRIES; p++)
136 {
137 phys_mem= vm_pt_base + p*PAGE_SIZE;
138 entry= phys_mem | I386_VM_USER | I386_VM_WRITE |
139 I386_VM_PRESENT;
140 if (phys_mem >= vm_pt_base + pt_size)
141 entry= 0;
142 phys_put32(vm_dir_base + p*I386_VM_PT_ENT_SIZE, entry);
143 }
144 vm_set_cr3(vm_dir_base);
145 level0(vm_enable_paging);
146}
147
148PRIVATE void phys_put32(addr, value)
149phys_bytes addr;
150u32_t value;
151{
152 phys_copy(vir2phys((vir_bytes)&value), addr, sizeof(value));
153}
154
155PRIVATE u32_t phys_get32(addr)
156phys_bytes addr;
157{
158 u32_t value;
159
160 phys_copy(addr, vir2phys((vir_bytes)&value), sizeof(value));
161
162 return value;
163}
164
165PRIVATE void vm_set_cr3(value)
166u32_t value;
167{
168 vm_cr3= value;
169 level0(set_cr3);
170}
171
172PRIVATE void set_cr3()
173{
174 write_cr3(vm_cr3);
175}
176
177PRIVATE void vm_enable_paging(void)
178{
179 u32_t cr0;
180
181 cr0= read_cr0();
182 write_cr0(cr0 | I386_CR0_PG);
183}
184
185PRIVATE void map_range(base, size, offset)
186u32_t base;
187u32_t size;
188u32_t offset;
189{
190 u32_t curr_pt, curr_pt_addr, entry;
191 int dir_ent, pt_ent;
192
193 if (base % PAGE_SIZE != 0)
194 panic("map_range: bad base", base);
195 if (size % PAGE_SIZE != 0)
196 panic("map_range: bad size", size);
197 if (offset % PAGE_SIZE != 0)
198 panic("map_range: bad offset", offset);
199
200 curr_pt= -1;
201 curr_pt_addr= 0;
202 while (size != 0)
203 {
204 dir_ent= (base >> I386_VM_DIR_ENT_SHIFT);
205 pt_ent= (base >> I386_VM_PT_ENT_SHIFT) & I386_VM_PT_ENT_MASK;
206 if (dir_ent != curr_pt)
207 {
208 /* Get address of page table */
209 curr_pt= dir_ent;
210 curr_pt_addr= phys_get32(vm_cr3 +
211 dir_ent * I386_VM_PT_ENT_SIZE);
212 curr_pt_addr &= I386_VM_ADDR_MASK;
213 }
214 entry= offset | I386_VM_USER | I386_VM_WRITE |
215 I386_VM_PRESENT;
216#if 0 /* Do we need this for memory mapped I/O? */
217 entry |= I386_VM_PCD | I386_VM_PWT;
218#endif
219 phys_put32(curr_pt_addr + pt_ent * I386_VM_PT_ENT_SIZE, entry);
220 offset += PAGE_SIZE;
221 base += PAGE_SIZE;
222 size -= PAGE_SIZE;
223 }
224}
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