Mercurial > lcfOS
annotate cos/kernel/mm.c @ 34:8012221dd740
Fixes for uninitialized data. This causes problems on real machines
author | windel |
---|---|
date | Mon, 16 Jan 2012 13:46:06 +0100 |
parents | 3a6a9b929db0 |
children | 5c20bd53cccd |
rev | line source |
---|---|
28 | 1 /* Memory manager functions, |
2 * | |
3 * Uses a bitmap to keep track of 4k pages that are in use. | |
4 * | |
5 * */ | |
26 | 6 |
7 #include "kernel.h" | |
8 | |
29 | 9 static uint64_t *frames = 0; |
10 static uint64_t nframes = 0; | |
26 | 11 |
29 | 12 memmap_t* kernel_map = 0; // kernel memory mapping |
13 memmap_t* current_map = 0; // The currently active memory mapping | |
14 | |
15 static void set_frame(uint64_t frame) | |
26 | 16 { |
17 uint64_t idx = frame / 64; | |
18 uint64_t off = frame % 64; | |
19 frames[idx] |= (0x1 << off); | |
20 } | |
21 | |
29 | 22 static void clear_frame(uint64_t frame) |
26 | 23 { |
24 uint64_t idx = frame / 64; | |
25 uint64_t off = frame % 64; | |
26 frames[idx] &= ~(0x1 << off); | |
27 } | |
28 | |
29 uint64_t test_frame(uint64_t frame) | |
30 { | |
31 uint64_t idx = frame / 64; | |
32 uint64_t off = frame % 64; | |
33 return (frames[idx] & (0x1 << off)); | |
34 } | |
35 | |
29 | 36 static uint64_t first_frame() |
26 | 37 { |
38 uint64_t i, j; | |
28 | 39 for (i = 0; i < nframes / 64; i++) |
26 | 40 { |
41 if (frames[i] != 0xFFFFFFFFFFFFFFFF) | |
42 { | |
43 for (j = 0; j < 64; j++) | |
44 { | |
45 uint64_t dut = 0x1 << j; | |
46 if ((frames[i] & dut) != dut) | |
47 { | |
48 return i*64+j; | |
49 } | |
50 } | |
51 } | |
52 } | |
29 | 53 |
54 // No frame found: | |
55 return (uint64_t) -1; | |
26 | 56 } |
57 | |
58 // Memory manager functions: | |
28 | 59 void init_memory(uint64_t total_mem_size) |
60 { | |
32
3a6a9b929db0
Added initial ramdisk and some virtual file system functions
windel
parents:
30
diff
changeset
|
61 // Only here placement malloc is used! |
3a6a9b929db0
Added initial ramdisk and some virtual file system functions
windel
parents:
30
diff
changeset
|
62 // |
29 | 63 // Allocate and clear bits to remember which 4kb-frames are in use: |
64 nframes = (total_mem_size / 0x1000); | |
65 frames = (uint64_t*)kmalloc_int( (nframes / 64) * sizeof(uint64_t) ); | |
66 memset(frames, 0, (nframes / 64) * sizeof(uint64_t)); | |
67 | |
68 // Create kernel map: | |
69 kernel_map = (memmap_t*)kmalloc_aligned_int(sizeof(memmap_t)); | |
70 memset(kernel_map, 0, sizeof(memmap_t)); | |
71 | |
72 // Identity map lower memory and mark as used by the kernel. | |
73 // Mark as used by the kernel: | |
74 uint64_t i; | |
75 i = 0; | |
76 while ( i <= placement_address) | |
77 { | |
78 page_t *page; | |
79 | |
80 page = get_page(i, kernel_map); // Get page for address | |
81 page->address = i >> 12; // Set the address of this page. | |
82 page->present = 1; | |
83 page->rw = 1; | |
84 page->us = 1; // Make all things accessable for users for now. | |
30 | 85 //page->pwt = 1; // Is this bit required? |
29 | 86 |
87 set_frame(i / 0x1000); | |
88 | |
89 i += 0x1000; // Increase a 4 k frame | |
90 } | |
91 | |
92 // Set the created mapping as active: | |
30 | 93 switch_mapping(kernel_map); |
94 | |
29 | 95 // TODO: set the use of placement malloc to invalid after here. |
28 | 96 } |
97 | |
29 | 98 void alloc_frame(page_t *page) |
26 | 99 { |
29 | 100 if (page->address != 0) |
101 { | |
102 return; | |
103 } | |
26 | 104 uint64_t idx = first_frame(); |
105 if (idx == (uint64_t) -1) | |
106 { | |
107 panic("No more memory!"); | |
108 } | |
109 set_frame(idx); | |
29 | 110 |
111 page->present = 1; | |
112 page->rw = 1; | |
113 page->us = 0; | |
114 page->address = idx; // set address in frame number, the byte address is 0x1000 times this value. | |
26 | 115 } |
116 | |
28 | 117 void free_frame(page_t *page) |
118 { | |
29 | 119 clear_frame(page->address / 0x1000); |
120 page->address = 0; | |
121 page->present = 0; | |
122 } | |
123 | |
124 void switch_mapping(memmap_t* mapping) | |
125 { | |
126 current_map = mapping; | |
127 | |
128 asm volatile("mov %0, %%cr3" :: "r"(&mapping->table)); | |
129 | |
130 // Enable paging (and flush cache): | |
131 uint64_t cr0; | |
132 asm volatile("mov %%cr0, %0": "=r"(cr0)); | |
133 cr0 |= 0x80000000; | |
134 asm volatile("mov %0, %%cr0":: "r"(cr0)); | |
28 | 135 } |
26 | 136 |
29 | 137 /* Get a page for a virtual address, and create other tables if required */ |
138 page_t* get_page(uint64_t address, memmap_t *mapping) | |
139 { | |
140 // Retrieve the correct PDP (page dir pointer table): | |
141 uint64_t pml4index = (address >> 39) & 0x1FF; | |
142 PDPT_t *pdpt = 0; | |
143 if (mapping->table[pml4index].present == 1) | |
144 { | |
145 pdpt = (PDPT_t*)((uint64_t)mapping->table[pml4index].address << 12); | |
146 } | |
147 else | |
148 { | |
149 // Create new table: | |
150 pdpt = (PDPT_t*)kmalloc_aligned_int(sizeof(PDPT_t)); | |
151 memset(pdpt, 0, sizeof(PDPT_t)); | |
152 | |
153 // TODO: get function like virt2phys or something here | |
154 uint64_t address = (uint64_t)pdpt; // get the physical address | |
155 mapping->table[pml4index].address = address >> 12; // shift right | |
156 mapping->table[pml4index].rw = 1; | |
157 mapping->table[pml4index].us = 1; | |
158 mapping->table[pml4index].present = 1; | |
159 } | |
160 | |
161 uint64_t pdptindex = (address >> 30) & 0x1FF; | |
162 // Retrieve the correct page directory: | |
163 PD_t *pd = 0; | |
164 if (pdpt->table[pdptindex].present == 1) | |
165 { | |
166 pd = (PD_t*)((uint64_t)pdpt->table[pdptindex].address << 12); | |
167 } | |
168 else | |
169 { | |
170 // Create a new table: | |
171 pd = (PD_t*)kmalloc_aligned_int(sizeof(PD_t)); | |
172 memset(pd, 0, sizeof(PD_t)); | |
173 | |
174 // Enter table into PDPT: | |
175 // TODO: make virt2phys function: | |
176 uint64_t address = (uint64_t)pd; | |
177 pdpt->table[pdptindex].address = address >> 12; | |
178 pdpt->table[pdptindex].rw = 1; | |
179 pdpt->table[pdptindex].us = 1; | |
180 pdpt->table[pdptindex].present = 1; | |
181 } | |
182 | |
183 // Retrieve the correct page table: | |
184 uint64_t pdindex = (address >> 21) & 0x1FF; | |
185 PT_t *pt = 0; | |
186 if (pd->table[pdindex].present == 1) | |
187 { | |
188 pt = (PT_t*)((uint64_t)pd->table[pdindex].address << 12); | |
189 } | |
190 else | |
191 { | |
192 // Create table: | |
193 pt = (PT_t*)kmalloc_aligned_int(sizeof(PD_t)); | |
194 memset(pt, 0, sizeof(PT_t)); | |
195 | |
196 // Enter PT into PD: | |
197 uint64_t address = (uint64_t)pt; | |
198 pd->table[pdindex].address = address >> 12; | |
199 pd->table[pdindex].rw = 1; | |
200 pd->table[pdindex].us = 1; | |
201 pd->table[pdindex].present = 1; | |
202 } | |
203 | |
204 // Finally get the page from the directory: | |
205 // TODO: convert from physical address to virtual address: | |
206 uint64_t ptindex = (address >> 12) & 0x1FF; | |
207 return &pt->table[ptindex]; | |
208 } | |
209 |