1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
#include "kernel.h"
#include "mem.h"
#include <stdint.h>
#include "multiboot.h"
#define PMMNGR_BLOCKS_PER_BYTE 8
#define PMMNGR_BLOCK_SIZE 4096
#define PMMNGR_MAX_BLOCKS 1048576 // 4096*1048576 = 2^32 bytes (maxium addressable memory ~4GB)
#define PMMNGR_MAP_SIZE PMMNGR_MAX_BLOCKS/PMMNGR_BLOCKS_PER_BYTE/4
// defined in linker.ld and asm_start.s
extern uint32_t kernel_start[];
extern uint32_t kernel_end[];
extern uint32_t stack_top[];
extern uint32_t stack_bottom[];
//memory map bit array. Each bit represents a 4KB memory block,
//so uint32_t represents 8*4 blocks
static uint32_t _mmngr_memory_map[PMMNGR_MAP_SIZE]; //128KiB
//track number of free blocks
static uint32_t mem_free_blocks; //number of free blocks
static char *memmap_type_to_string[]=
{
"Usable",
"Reserved",
"ACPI reclaimable",
"ACPI NVS",
"Bad Memory"
};
// bit funcs!
static void mmap_set(int bit)
{
_mmngr_memory_map[bit / 32] |= (1 << (bit % 32));
}
static void mmap_unset(int bit)
{
_mmngr_memory_map[bit / 32] &= ~ (1 << (bit % 32));
}
static int mmap_test(int bit)
{
return _mmngr_memory_map[bit / 32] & (1 << (bit % 32));
}
//
// By default, Set all of memory is in use
static void pmmngr_init ()
{
mem_free_blocks=0;
for(int i=0;i<PMMNGR_MAP_SIZE;i++)
{
_mmngr_memory_map[i]=0xffffffff;
}
}
//find the first free bit
static int mmap_first_free ()
{
for (int i=0; i<PMMNGR_MAP_SIZE; i++)
if (_mmngr_memory_map[i] != 0xffffffff)
for (int j=0; j<32; j++)
{
if(!mmap_test(32*i+j))return 32*i+j;
}
return -1;
}
// work with regions
static void pmmngr_init_region (uint32_t base, uint32_t size)
{
uint32_t align = base / PMMNGR_BLOCK_SIZE;
uint32_t end_align = (base+size-1) / PMMNGR_BLOCK_SIZE;
uint32_t blocks = end_align-align+1;
for (; blocks>0; blocks--)
{
// if(mmap_test(align))kpanic("already initialized");
mmap_unset (align++);
mem_free_blocks++;
}
}
static void pmmngr_deinit_region (uint32_t base, uint32_t size)
{
uint32_t align = base / PMMNGR_BLOCK_SIZE;
uint32_t end_align = (base+size-1) / PMMNGR_BLOCK_SIZE;
uint32_t blocks = end_align-align+1;
if(size%PMMNGR_BLOCK_SIZE)blocks++;
for (; blocks>0; blocks--)
{
// if(mmap_test(align))kpanic("already de-initialized");
mmap_set (align++);
mem_free_blocks--;
}
}
void* mem_alloc_block ()
{
int frame = mmap_first_free ();
if (frame == -1)
{
kpanic("OUT OF MEMORY (alloc_block)");
return 0; //out of memory
}
mmap_set (frame);
mem_free_blocks--;
uint32_t addr = frame * PMMNGR_BLOCK_SIZE;
//klog("alloc block (%d) 0x%08X)",frame,addr);
return (void*)addr;
}
void mem_free_block (void* p)
{
uint32_t addr = (uint32_t)(uint32_t*)p;
int frame = addr / PMMNGR_BLOCK_SIZE;
if(mmap_test(frame))
{
mmap_unset (frame);
mem_free_blocks++;
}
else
{
//klog("free block (%d) 0x%08X)",frame,addr);
kpanic("trying to free, free physical mem!");
}
//klog("free block (%d) 0x%08X)",frame,addr);
}
uint32_t mem_get_free_blocks_count()
{
return mem_free_blocks;
}
/** initialize physical memory manager */
uint32_t mem_init(multiboot_information *info)
{
klog("markers in kernel binary:");
klog("kernel loaded at: 0x%08X- 0x%08X",kernel_start,kernel_end);
klog("initial stack at: 0x%08X- 0x%08X",stack_top,stack_bottom);
fixme("check if kernel/ramimage size/pos does not exceed first 32mb (better vmem dynamically) limits!");
fixme("communicate pages to vmmem to identity map in kernel!");
if(info->flags&&1<<6)
{
klog("Memory map of length %d provided by bootloader",info->mmap_length);
}
else kpanic("Unable to continue without memory map, sorry!");
pmmngr_init (); //mark all memory as used
uint64_t memmap=info->mmap_addr;
uint64_t length=info->mmap_length;
uint32_t total_mem=0;
// iterate : print memory map, calc blocks, deinit
for(uint32_t mmap_addr=memmap;mmap_addr<memmap+length;)
{
multiboot_mmap *mmap=(multiboot_mmap *)mmap_addr;
uint64_t mem_start=mmap->base_addr;
uint64_t mem_end=mmap->base_addr+mmap->length;
klog("%08X - %08X (%d bytes)/ type: %s, (size: %d)",
(uint32_t)mem_start, (uint32_t)mem_end, (uint32_t)(mem_end-mem_start), memmap_type_to_string[mmap->type-1], mmap->size);
uint32_t mem=mmap->length;
//reclaimable OR usable
if(mmap->type==1||mmap->type==3)
{
total_mem+=mem;
pmmngr_init_region(mmap->base_addr,mmap->length);
}
//next
mmap_addr+=mmap->size+4;
}
// deinit first page (coz address=0 reserved for failure)
pmmngr_deinit_region(0,4096);
// deinit modules memory
if(info->flags&&1<<3)
{
multiboot_mod *mod=(multiboot_mod *)info->mods_addr;
for(int i=0;i<info->mods_count;i++)
{
klog("mod 0x%08X-0x%08X : %s",
mod->mod_start,mod->mod_end, mod->string);
pmmngr_deinit_region(mod->mod_start,((uint32_t)mod->mod_end-(uint32_t)mod->mod_start));
mod++;
}
}
// deinitialize kernel simply with this:
pmmngr_deinit_region(kernel_start,((uint32_t)kernel_end-(uint32_t)kernel_start)+1);
// or better via ELF symbols: (TODO!)
if(info->flags&&1<<5)
{
fixme("parse ELF sections of our kernel.");
}
else kpanic("Can not find ELF symbols.");
klog("Free 4K blocks: %d",mem_free_blocks);
klog("Usable ~%d / %d MB ",mem_free_blocks*4096/1024/1024,total_mem/1024/1024);
return 0;
}
|
