118 lines
2.6 KiB
C
118 lines
2.6 KiB
C
#include <grub/multiboot.h>
|
|
#include "../halt.h"
|
|
#include <stdint.h>
|
|
#include <stdlib.h>
|
|
#include <klog.h>
|
|
|
|
static char bmap[131072];
|
|
|
|
static char get_bmap_bit(int index) {
|
|
int byte=index/8;
|
|
int bit=index%8;
|
|
char entry=bmap[byte];
|
|
return (entry&(1<<bit))>0;
|
|
}
|
|
|
|
static void set_bmap_bit(int index) {
|
|
int byte=index/8;
|
|
int bit=index%8;
|
|
bmap[byte]=bmap[byte]|(1<<bit);
|
|
}
|
|
|
|
static void clear_bmap_bit(int index) {
|
|
int byte=index/8;
|
|
int bit=index%8;
|
|
bmap[byte]=bmap[byte]&(~(1<<bit));
|
|
}
|
|
|
|
void pmem_init(multiboot_info_t* mbd) {
|
|
if (!mbd->flags&&MULTIBOOT_INFO_MEM_MAP) {
|
|
klog("PANIC","No memory map supplied by bootloader!");
|
|
halt();
|
|
}
|
|
for (int i=0;i<131072;i++) {
|
|
bmap[i]=0xFF;
|
|
}
|
|
uint32_t mmap_length=mbd->mmap_length;
|
|
struct multiboot_mmap_entry* mmap_addr=(struct multiboot_mmap_entry*)(mbd->mmap_addr+0xC0000000);
|
|
struct multiboot_mmap_entry* mmap_entry=mmap_addr;
|
|
uint32_t size;
|
|
for (int i=0;(uint32_t)mmap_entry<((uint32_t)mmap_addr+mmap_length);mmap_entry=(struct multiboot_mmap_entry*)((uint32_t)mmap_entry+size+4)) {
|
|
size=mmap_entry->size;
|
|
uint32_t start=mmap_entry->addr;
|
|
uint32_t end=start+mmap_entry->len-1;
|
|
uint32_t type=mmap_entry->type;
|
|
if (type!=1 || start<0x100000) {
|
|
continue;
|
|
}
|
|
if (start&0xFFF) {
|
|
start+=0x1000;
|
|
}
|
|
start=start>>12;
|
|
end=end>>12;
|
|
for (uint32_t i=start;i<end;i++) {
|
|
clear_bmap_bit(i);
|
|
}
|
|
i++;
|
|
}
|
|
for (uint32_t i=0;i<2048;i++) {
|
|
set_bmap_bit(i);
|
|
}
|
|
}
|
|
|
|
void* pmem_alloc(int num_pages) {
|
|
uint32_t bmap_index;
|
|
uint32_t remaining_blks;
|
|
for(uint32_t i=0;i<131072;i++) {
|
|
if (bmap[i]!=0xFF) {
|
|
char got_0=0;
|
|
remaining_blks=num_pages;
|
|
uint32_t old_j;
|
|
for (uint32_t j=i*8;;j++) {
|
|
char bit=get_bmap_bit(j);
|
|
if (got_0) {
|
|
if (bit) {
|
|
if (remaining_blks==0) {
|
|
bmap_index=old_j;
|
|
break;
|
|
} else {
|
|
i+=j/8;
|
|
i--;
|
|
break;
|
|
}
|
|
} else {
|
|
remaining_blks--;
|
|
}
|
|
} else {
|
|
if (!bit) {
|
|
got_0=1;
|
|
old_j=j;
|
|
remaining_blks--;
|
|
}
|
|
}
|
|
if (remaining_blks==0) {
|
|
bmap_index=old_j;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (remaining_blks==0) {
|
|
break;
|
|
}
|
|
}
|
|
if (remaining_blks!=0) {
|
|
return NULL;
|
|
}
|
|
for (int i=0;i<num_pages;i++) {
|
|
set_bmap_bit(bmap_index+i);
|
|
}
|
|
void* addr=(void*)(bmap_index<<12);
|
|
return addr;
|
|
}
|
|
|
|
void pmem_free(int start_page,int num_pages) {
|
|
for (int i=start_page;i<num_pages;i++) {
|
|
set_bmap_bit(i);
|
|
}
|
|
}
|