Files
bsb2/kernel/memory/pageframealloc.cc
2026-01-11 21:29:41 +01:00

107 lines
3.0 KiB
C++

#include "../memory/pageframealloc.h"
#include "../boot/multiboot/data.h"
#include "pageframe.h"
#include "../debug/output.h"
#include "../memory/config.h"
#include "../arch/lapic.h"
#include "../arch/apic.h"
uint8_t PageFrameAllocator::bitmap[4294967296 / 4096 / 8];
void mark_unavailable(uintptr_t start, uintptr_t end){
DBG << "start: " << hex << start << " end: " << end << endl;
for(uint64_t i = start; i < end; i += 4096){
uint64_t pg = i/4096;
PageFrameAllocator::bitmap[pg/8] &= ~(1 << pg%8);
}
}
void PageFrameAllocator::init(){
Multiboot::Memory* memory_map_entry = Multiboot::getMemoryMap();
dout << "kernel start: " << ___KERNEL_START___;
dout << " kernel end: " << ___KERNEL_END___ << endl;
while(memory_map_entry != 0){
void* start = memory_map_entry->getStartAddress();
void* end = memory_map_entry->getEndAddress();
bool available = memory_map_entry->isAvailable();
//TODO priotity for conflicting regions
for(uint64_t i = (uint64_t)start; i < (uint64_t)end; i += 4096){
uint64_t pg = i/4096;
if(available)
bitmap[pg/8] |= 1 << pg%8;
else
bitmap[pg/8] &= ~(1 << pg%8);
}
memory_map_entry = memory_map_entry->getNext();
}
DBG << "kernel image ";
mark_unavailable((uintptr_t)&___KERNEL_START___, (uintptr_t)&___KERNEL_END___);
DBG << "ISA adresses ";
mark_unavailable(0x00F00000, 0x00FFFFFF);
DBG << "LAPIC ";
mark_unavailable(0xfee00000, 0xfee003f0);
DBG << "IO APIC ";
mark_unavailable(APIC::getIOAPICAddress(), APIC::getIOAPICAddress()+0x10);
stats();
}
void PageFrameAllocator::stats(){
Multiboot::Memory* memory_map_entry = Multiboot::getMemoryMap();
while(memory_map_entry != 0){
void* start = memory_map_entry->getStartAddress();
void* end = memory_map_entry->getEndAddress();
bool available = memory_map_entry->isAvailable();
DBG << "Memory: " << hex << start << " to " << end << " is available: " << available << "." << endl;
memory_map_entry = memory_map_entry->getNext();
}
uint64_t pages_available = 0;
for(uint64_t i=0; i<sizeof(bitmap)*8;i++)
{
if(bitmap[i/8] & (1<<i%8))
pages_available++;
}
for(uint64_t i=0; i < 0x2000000/4096/8; i++){
if(i%64 == 0){
DBG << endl << hex << i * 8 * 4096 << " " << flush;
int x,y;
dout.getPos(x,y);
for(uint8_t i=x; i<10; i++){
DBG<<" ";
}
}
if(bitmap[i] == 0xff)
DBG << '#';
else if(bitmap[i] == 0x00)
DBG << '.';
else
DBG << '/';
}
DBG << "\npages available: " << dec << pages_available << endl;
}
PageFrame* PageFrameAllocator::alloc(bool kernel){
(void) kernel;
return 0;
}
void PageFrameAllocator::free(PageFrame* frame){
(void) frame;
}
void PageFrameAllocator::free(uintptr_t addr){
(void) addr;
}