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#include <lib/lib.h>
#include <memory/alloc.h>
#include <memory/paging.h>
#include <stdint.h>
#include <system.h>
int paging_enabled = 0;
u32 root_dir[1024][1024] __attribute__((aligned(4096)));
struct page_directory *paging_directory; // Current
struct page_directory *paging_kernel_directory = (struct page_directory *)root_dir;
void paging_init(struct page_directory *dir, int user)
{
for (u32 i = 0; i < 1024; i++) {
for (u32 j = 0; j < 1024; j++) {
paging_directory->tables[i]->pages[j] =
((j * 0x1000) + (i * PAGE_SIZE)) | PT_RW | (user ? PT_USER : 0);
}
}
for (u32 i = 0; i < 1024; i++) {
paging_directory->tables[i] = ((u32)paging_directory->tables[i]) | PD_RW |
PD_PRESENT | (user ? PD_USER : 0);
}
}
struct page_directory *paging_make_directory(int user)
{
struct page_directory *dir = (struct page_directory *)malloc(sizeof(struct page_directory));
paging_init(dir, user);
return dir;
}
extern u32 end;
void paging_install(u32 multiboot_address)
{
// Kernel paging
paging_switch_directory(paging_directory);
paging_init(paging_directory, 0);
if (!memory_init(multiboot_address))
paging_set_present(0, memory_get_all() >> 3); // /4
paging_set_used(0, ((u32)end >> 12) + 1); // /4096
log("Enabling");
paging_enable();
log("Installed paging");
}
void paging_disable()
{
u32 cr0;
asm("mov %%cr0, %0" : "=r"(cr0));
cr0 &= 0x7fffffff;
asm("mov %0, %%cr0" ::"r"(cr0));
paging_enabled = 0;
}
void paging_enable()
{
asm("mov %0, %%cr3" ::"r"(paging_directory));
u32 cr0;
asm("mov %%cr0, %0" : "=r"(cr0));
cr0 |= 0x80000000;
asm("mov %0, %%cr0" ::"r"(cr0));
paging_enabled = 1;
}
void paging_switch_directory(struct page_directory *dir)
{
paging_directory = dir;
asm("mov %0, %%cr3" ::"r"(paging_directory));
}
void invlpg(u32 addr)
{
asm("invlpg (%0)" ::"r"(addr) : "memory");
}
void paging_map(u32 phy, u32 virt, u16 flags)
{
u32 pdi = virt >> 22;
u32 pti = virt >> 12 & 0x03FF;
paging_directory->tables[pdi]->pages[pti] = phy | flags;
invlpg(virt);
}
u32 paging_get_phys(u32 virt)
{
u32 pdi = virt >> 22;
u32 pti = (virt >> 12) & 0x03FF;
return paging_directory->tables[pdi]->pages[pti] & 0xFFFFF000;
}
u16 paging_get_flags(u32 virt)
{
u32 pdi = virt >> 22;
u32 pti = (virt >> 12) & 0x03FF;
return paging_directory->tables[pdi]->pages[pti] & 0xFFF;
}
void paging_set_flag_up(u32 virt, u32 count, u32 flag)
{
u32 page_n = virt / 0x1000;
for (u32 i = page_n; i < page_n + count; i++) {
paging_directory->tables[i / 1024]->pages[i % 1024] |= flag;
invlpg(i * 0x1000);
}
}
void paging_set_flag_down(u32 virt, u32 count, u32 flag)
{
u32 page_n = virt / 0x1000;
for (u32 i = page_n; i < page_n + count; i++) {
paging_directory->tables[i / 1024]->pages[i % 1024] &= ~flag;
invlpg(i * 0x1000);
}
}
void paging_set_present(u32 virt, u32 count)
{
paging_set_flag_up(virt, count, PT_PRESENT);
}
void paging_set_absent(u32 virt, u32 count)
{
paging_set_flag_down(virt, count, PT_PRESENT);
}
void paging_set_used(u32 virt, u32 count)
{
paging_set_flag_up(virt, count, PT_USED);
}
void paging_set_free(u32 virt, u32 count)
{
paging_set_flag_down(virt, count, PT_USED);
}
void paging_set_user(u32 virt, u32 count)
{
u32 page_n = virt / 0x1000;
for (u32 i = page_n; i < page_n + count; i += 1024) {
paging_directory->tables[i] = ((u32)paging_directory->tables[i]) | PD_USER;
}
paging_set_flag_up(virt, count, PT_USER);
}
u32 paging_find_pages(u32 count)
{
u32 continuous = 0;
u32 start_dir = 0;
u32 start_page = 0;
for (u32 i = 0; i < 1024; i++) {
for (u32 j = 0; j < 1024; j++) {
if (!(paging_directory->tables[i]->pages[j] & PT_PRESENT) ||
(paging_directory->tables[i]->pages[j] & PT_USED)) {
continuous = 0;
start_dir = i;
start_page = j + 1;
} else {
if (++continuous == count)
return (start_dir * 0x400000) + (start_page * 0x1000);
}
}
}
panic("Out of memory!");
return 0;
}
u32 paging_alloc_pages(u32 count)
{
u32 ptr = paging_find_pages(count);
paging_set_used(ptr, count);
paging_set_user(ptr, count);
return ptr;
}
u32 paging_get_used_pages()
{
u32 n = 0;
for (u32 i = 0; i < 1024; i++) {
for (u32 j = 0; j < 1024; j++) {
u8 flags = paging_directory->tables[i]->pages[j] & PT_USED;
if (flags == 1)
n++;
}
}
return n;
}
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