42_KFS/src/memory/memory.c
2024-11-19 16:57:19 +01:00

109 lines
3.4 KiB
C

#include "memory.h"
#include "debug.h"
#include "kprintf.h"
#include "string.h"
#include "utils.h"
#include <stdint.h>
uint32_t *page_directory = &boot_page_directory;
uint32_t page_table_default[1024] __attribute__((aligned(PAGE_SIZE)));
uint32_t multiboot_page_table[1024] __attribute__((aligned(PAGE_SIZE)));
uint32_t frame_zones_page_table[1024] __attribute__((aligned(PAGE_SIZE)));
uint32_t mem_size;
multiboot_memory_map_t *mmap_addr;
multiboot_uint32_t mmap_length;
struct frame_zone *head;
static void init_multiboot(multiboot_info_t *mbd, uint32_t magic)
{
if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
kpanic("invalid magic number! (git good skill issue)");
init_page_table(multiboot_page_table, 0);
page_directory[1023] =
((uint32_t)multiboot_page_table - HEAP_END) | 0x03;
const size_t mbd_size = CEIL(
(uint32_t)mbd % PAGE_SIZE + sizeof(multiboot_info_t), PAGE_SIZE);
// Index multiboot_info_t struct
for (uint32_t i = 0; i < mbd_size; i++)
multiboot_page_table[i] =
(((uint32_t)mbd + PAGE_SIZE * i) & PAGE_MASK) | INIT_FLAGS;
multiboot_info_t *mbd_virt =
(multiboot_info_t *)(GET_PAGE_ADDR(1023, 0) +
(uint32_t)mbd % PAGE_SIZE);
// Index mbd->mmap_addr pointers
for (uint32_t i = 0; i < mbd_virt->mmap_length; i++)
multiboot_page_table[i + mbd_size] =
((mbd_virt->mmap_addr + i * PAGE_SIZE) & PAGE_MASK) |
INIT_FLAGS;
mmap_addr = (multiboot_memory_map_t *)(GET_PAGE_ADDR(1023, mbd_size) +
(uint32_t)mbd_virt->mmap_addr %
PAGE_SIZE);
mmap_length = mbd_virt->mmap_length / sizeof(multiboot_memory_map_t);
}
static void add_frame_node(multiboot_memory_map_t *mmmt)
{
static uint32_t index;
void *zone = (void *)mmmt->addr;
init_page_table(frame_zones_page_table, 0);
page_directory[1022] =
((uint32_t)frame_zones_page_table - HEAP_END) | 0x03;
frame_zones_page_table[index] =
((uint32_t)zone & PAGE_MASK) | INIT_FLAGS;
struct frame_zone *current =
(struct frame_zone *)GET_PAGE_ADDR(1022, index++);
memset(current, 0, sizeof(struct frame_zone));
current->addr = (void *)mmmt->addr;
current->frame_table = (uint32_t *)current + sizeof(struct frame_zone);
const size_t frame_table_size =
CEIL(current->size - sizeof(struct frame_zone), PAGE_SIZE * 32);
for (uint32_t i = index; index - i < CEIL(frame_table_size, PAGE_SIZE);
index++)
frame_zones_page_table[index] =
((uint32_t)zone + PAGE_SIZE & PAGE_MASK) | INIT_FLAGS;
// glhf reading this bozo
current->len = mmmt->len;
current->size = (mmmt->len - (sizeof(struct frame_zone) +
(mmmt->len / PAGE_SIZE) / 32));
current->remaining_frames = current->size / PAGE_SIZE;
current->first_free_frame = 0;
current->next = NULL;
if (!head) {
head = current;
return;
}
struct frame_zone *it = head;
while (it->next)
it = it->next;
it->next = current;
}
static void init_frame_zones(void)
{
for (uint32_t i = 0; i < mmap_length; i++) {
multiboot_memory_map_t *mmmt =
(multiboot_memory_map_t *)mmap_addr + i;
if (mmmt->type == MULTIBOOT_MEMORY_AVAILABLE)
add_frame_node(mmmt);
}
}
void init_memory(multiboot_info_t *mbd, uint32_t magic)
{
assert(page_directory);
for (uint16_t i = 0; i < 0x300; i++)
page_directory[i] = 0x02;
init_page_table(page_table_default, 0);
page_directory[0] = ((uint32_t)page_table_default - HEAP_END) | 0x03;
init_multiboot(mbd, magic);
init_frame_zones();
}